Semiconductor device and method for manufacturing semiconductor device

Abstract

Provided is a semiconductor device having good reliability. A semiconductor device includes an oxide semiconductor, a first conductor and a second conductor separated from each other on the oxide semiconductor, and a first insulator disposed on the first conductor and the second conductor and having an opening overlapping a region between the first conductor and the second conductor. A second insulator disposed in the opening of the first insulator; a third conductor disposed on the second insulator in the opening of the first insulator; a third insulator in contact with the top surface of the third conductor, the upper end portion of the second insulator, and the top surface of the first insulator; and a fourth insulator in contact with the top surface of the third insulator. The third insulator and the fourth insulator are metal oxides, and the third insulator has a higher carbon concentration than the fourth insulator.

Description

Technical Field

[0001] One aspect of the present invention relates to a semiconductor device, a memory device, and an electronic device using an oxide semiconductor. Another aspect of the present invention relates to a method for manufacturing the aforementioned semiconductor device.

[0002] Note that one aspect of the present invention is not limited to the technical fields described above. Examples of technical fields encompassing one aspect of the present invention include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), and driving or manufacturing methods for the aforementioned devices.

[0003] Note that in this specification, etc., a semiconductor device refers to any device capable of operating by utilizing the characteristics of semiconductors. Besides semiconductor elements such as transistors, semiconductor circuits, arithmetic processing devices, and storage devices are also types of semiconductor devices. Sometimes it can be said that display devices (liquid crystal displays, light-emitting displays, etc.), projection devices, lighting devices, electro-optical devices, energy storage devices, storage devices, semiconductor circuits, imaging devices, electronic devices, etc., include semiconductor devices. Background Technology

[0004] In recent years, semiconductor devices have been developed, with LSI (Large Scale Integration), CPU (Central Processing Unit), and memory being the main components used in semiconductor devices. A CPU is an assembly of semiconductor integrated circuits (including at least transistors and memory) formed by processing semiconductor wafers to create chips, and semiconductor elements having electrodes formed as connection terminals.

[0005] Semiconductor circuits (IC chips) such as LSI, CPU, and memory are mounted on circuit boards, such as printed circuit boards, and are used as components of various electronic devices.

[0006] Furthermore, the technique of constructing transistors using semiconductor thin films formed on substrates with insulating surfaces has attracted considerable attention. These transistors are widely used in electronic devices such as integrated circuits (ICs) and image display devices (simply referred to as display devices). Silicon-based semiconductor materials are widely known as semiconductor thin films that can be used in transistors. Among other materials, oxide semiconductors have also garnered attention.

[0007] Furthermore, it is known that the leakage current of transistors using oxide semiconductors is extremely small in the non-conducting state. For example, Patent Document 1 discloses a low-power CPU that utilizes the characteristic of low leakage current of transistors using oxide semiconductors. Additionally, for example, Patent Document 2 discloses a storage device that utilizes the characteristic of low leakage current of transistors using oxide semiconductors to achieve long-term retention of stored content.

[0008] In addition, Patent Document 3 discloses a transistor with a microstructure in which an active electrode layer and a drain electrode layer are disposed in contact with the top surface of an oxide semiconductor. [Preliminary Technology Documents] [Patent Literature]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2012-257187 [Patent Document 2] Japanese Patent Application Publication No. 2011-151383 [Patent Document 3] International Patent Application Publication No. 2016-125052 Summary of the Invention The technical problem that the invention aims to solve

[0010] One objective of this invention is to provide a semiconductor device with high reliability. Another objective is to provide a semiconductor device with good electrical characteristics. Another objective is to provide a semiconductor device with small non-uniformity in the electrical characteristics of its transistors. Another objective is to provide a semiconductor device that can be miniaturized or highly integrated. Another objective is to provide a semiconductor device with high operating speed. Another objective is to provide a semiconductor device with low power consumption. Another objective is to provide a novel semiconductor device. Another objective is to provide a method for manufacturing a semiconductor device with high productivity. Another objective is to provide a novel method for manufacturing a semiconductor device. Another objective is to provide a novel display device.

[0011] Note that the description of these objectives does not preclude the existence of other objectives. One aspect of the invention does not necessarily require achieving all of the above objectives. Objectives other than those described above can be extracted from the description, drawings, and claims. means of solving technical problems

[0012] One aspect of the present invention is a semiconductor device comprising an oxide semiconductor, a first conductor and a second conductor disposed on the oxide semiconductor and separated from each other, a first insulator disposed on the first conductor and the second conductor and having an opening overlapping a region between the first conductor and the second conductor, a second insulator disposed within the opening of the first insulator and in contact with the top surface of the oxide semiconductor, a side surface of the first conductor, a side surface of the second conductor, and a side surface of the first insulator, and a third conductor disposed within the opening of the first insulator on the second insulator and having a region overlapping the second insulator and the oxide semiconductor. The insulator comprises: a third insulator that contacts the top surface of the third conductor, the upper end of the second insulator, and the top surface of the first insulator; a fourth insulator that contacts the top surface of the third insulator; a fifth insulator that contacts the top surface of the fourth insulator; a fourth conductor disposed in the opening formed in the first, third, fourth, and fifth insulators and reaching the first conductor; and a fifth conductor disposed in the opening formed in the first, third, fourth, and fifth insulators and reaching the second conductor. The third and fourth insulators are both metal oxides, and the carbon concentration of the third insulator is higher than that of the fourth insulator.

[0013] In the above structure, the third insulator and the fourth insulator preferably both contain aluminum oxide.

[0014] Furthermore, in the above structure, the third insulator preferably has a carbon concentration of 1×10⁻⁶. 19 atoms / cm 3 Above and 1×10 21 atoms / cm 3 The following areas.

[0015] Furthermore, in the above structure, the fourth insulator preferably has a carbon concentration of 4.46 × 10⁻⁶. 17 atoms / cm 3 Above and 1×10 19 atoms / cm 3 The following areas.

[0016] In addition, in the above structure, the fifth insulator preferably comprises silicon nitride.

[0017] Another aspect of the present invention is a method for manufacturing a semiconductor device, comprising the steps of: forming a transistor including an oxide semiconductor, a first conductor and a second conductor separated from each other on the oxide semiconductor, a first insulator disposed on the first conductor and the second conductor and having an opening overlapping a region between the first conductor and the second conductor, a second insulator disposed within the opening of the first insulator and contacting the top surface of the oxide semiconductor, a side surface of the first conductor, a side surface of the second conductor, and a side surface of the first insulator, and a third conductor disposed within the opening of the first insulator on the second insulator and having a region overlapping the second insulator with the oxide semiconductor; and for use with the third... A third insulator is deposited in contact with the top surface of the conductor, the upper end of the second insulator, and the top surface of the first insulator; a fourth insulator is deposited in contact with the top surface of the third insulator; a fifth insulator is deposited in contact with the top surface of the fourth insulator; openings leading to the first conductor and the second conductor are formed in the first, third, fourth, and fifth insulators; the first insulator is heat-treated; a fourth conductor is formed in the opening leading to the first conductor and a fifth conductor is formed in the opening leading to the second conductor; in the deposition of the third insulator, alumina is deposited using a thermal ALD method; and in the deposition of the fourth insulator, alumina is deposited using a sputtering method in an oxygen-containing atmosphere. Furthermore, in the above structure, the heat treatment is preferably carried out in an atmosphere containing nitrogen gas at a temperature of 350°C or higher and 450°C or lower.

[0019] Furthermore, in the above structure, it is preferable to deposit silicon nitride using a sputtering method in the deposition of the fifth insulator. Invention Effects

[0020] According to one aspect of the present invention, a semiconductor device with high reliability can be provided. Furthermore, according to one aspect of the present invention, a semiconductor device with good electrical characteristics can be provided. Furthermore, according to one aspect of the present invention, a semiconductor device with small non-uniformity in the electrical characteristics of transistors can be provided. Furthermore, according to one aspect of the present invention, a semiconductor device capable of miniaturization or high integration can be provided. Furthermore, according to one aspect of the present invention, a semiconductor device with high operating speed can be provided. Furthermore, according to one aspect of the present invention, a semiconductor device with low power consumption can be provided. Furthermore, according to one aspect of the present invention, a novel semiconductor device can be provided. Furthermore, according to one aspect of the present invention, a method for manufacturing a semiconductor device with high productivity can be provided. Furthermore, according to one aspect of the present invention, a novel method for manufacturing a semiconductor device can be provided. Furthermore, according to one aspect of the present invention, a novel display device can be provided.

[0021] Note that the description of these effects does not preclude the existence of other effects. One aspect of the invention does not necessarily require all of the aforementioned effects. Furthermore, effects other than those described above can be extracted from the description, drawings, and claims. Brief description of the attached figures

[0022] Figure 1A This is a plan view showing an example of a semiconductor device. Figures 1B to 1D This is a cross-sectional view showing an example of a semiconductor device. Figure 2A and Figure 2B This is a cross-sectional view showing an example of a semiconductor device. Figure 3A and Figure 3B This is a cross-sectional view showing an example of a semiconductor device. Figure 4A and Figure 4B This is a cross-sectional view showing an example of a semiconductor device. Figure 5A This is a plan view showing an example of a semiconductor device. Figures 5B to 5D This is a cross-sectional view showing an example of a semiconductor device. Figure 6A This is a plan view showing an example of a semiconductor device. Figures 6B to 6D This is a cross-sectional view showing an example of a semiconductor device. Figure 7A and Figure 7B This is a cross-sectional view showing an example of a semiconductor device. Figure 8A and Figure 8B This is a cross-sectional view showing an example of a semiconductor device. Figure 9A and Figure 9B This is a cross-sectional view showing an example of a semiconductor device. Figures 10A to 10E This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figures 11A to 11C This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figures 12A1 to 12D2 This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figures 13A to 13C This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figures 14A to 14C This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figures 15A to 15C This is a cross-sectional view illustrating an example of a method for manufacturing a semiconductor device. Figure 16A and Figure 16B This is an example of the structure of a display device. Figure 17 This is an example of the structure of a display device. Figure 18 This is an example of the structure of a display device. Figure 19 This is an example of the structure of a display device. Figures 20A to 20C This is an example of the structure of a display device. Figure 21A and Figure 21B This is an example of the structure of a display device. Figure 22A and Figure 22B This is a diagram illustrating an example of the structure of a display device. Figures 23A to 23D This is a diagram illustrating an example of the structure of a display device. Figures 24A to 24D This is a diagram illustrating an example of the structure of a display device. Figure 25 This is a diagram illustrating an example of the structure of a display device. Figures 26A to 26D This is an example of the structure of an electronic device. Figures 27A to 27F This is an example of the structure of an electronic device. Figures 28A to 28G This is an example of the structure of an electronic device. Figures 29A to 29C This is a cross-sectional STEM image according to an embodiment. Figure 30 This is a cross-sectional STEM image according to an embodiment. Figure 31A and Figure 31B This is a diagram illustrating the electrical characteristics according to an embodiment. Figure 32 This is a graph showing the results of a reliability evaluation according to an embodiment. Figure 33A and Figure 33B This is a graph showing the results of a reliability evaluation according to an embodiment. Figure 34 This is a graph showing the results of the SIMS analysis according to an embodiment. Figure 35A and Figure 35B This is a cross-sectional schematic diagram according to an embodiment. Figure 36A and Figure 36B This is a cross-sectional STEM image according to an embodiment. Figure 37A and Figure 37B This is a cross-sectional STEM image according to an embodiment. Figure 38A and Figure 38B This is a diagram illustrating the electrical characteristics according to an embodiment. Figures 39A to 39H This is a diagram illustrating the electrical characteristics according to an embodiment. Figure 40A and Figure 40B This is a diagram illustrating the electrical characteristics according to an embodiment. Figure 41A and Figure 41B This is a diagram illustrating the electrical characteristics according to an embodiment. Figure 42A and Figure 42B This is a diagram illustrating the electrical characteristics according to an embodiment. Figure 43 This is a graph showing the results of a reliability evaluation according to an embodiment. Methods of implementing the invention

[0023] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments shown below.

[0024] Note that in the structure of the invention described below, the same symbols are used in different figures to represent the same parts or parts with the same function, and repeated descriptions are omitted. Furthermore, when representing parts with the same function, the same shading lines are sometimes used without additional symbols.

[0025] Furthermore, for ease of understanding, the positions, sizes, and extents of the constituent elements shown in the accompanying drawings may not represent their actual positions, sizes, and extents. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and extents disclosed in the accompanying drawings.

[0026] Note that, for convenience, ordinal numbers such as "first" and "second" are used in this specification, etc., but these do not limit the number of constituent elements or the order of the constituent elements (e.g., process sequence or stacking sequence). Furthermore, the ordinal numbers used for constituent elements in one part of this specification may sometimes differ from those used for the same constituent element in other parts of this specification or in the claims.

[0027] Furthermore, depending on the circumstances, the "film" and "layer" can be interchanged. For example, a "conductive layer" can be replaced with a "conductive film." Additionally, an "insulating film" can be replaced with an "insulating layer." Furthermore, depending on the circumstances, a "conductor" can be replaced with a "conductive layer" or a "conductive film." Furthermore, depending on the circumstances, an "insulator" can be replaced with an "insulating layer" or an "insulating film."

[0028] Openings include, for example, grooves and slits. Furthermore, the area where an opening is formed is sometimes referred to as an opening portion.

[0029] Furthermore, the accompanying drawings used in this specification and the like show the case where the sidewall of the insulator in the opening of the insulator is perpendicular or substantially perpendicular to the substrate surface or the surface to which it is formed, but the sidewall may also be tapered.

[0030] Note that in this specification, a conical shape refers to a shape in which at least a portion of the side surface of a constituent element is inclined relative to the substrate surface or the surface to be formed. For example, it is preferable to have a region where the angle (hereinafter sometimes referred to as the cone angle) formed by the inclined side surface and the substrate surface or the surface to be formed is less than 90°. Note that the side surface of the constituent element and the substrate surface do not necessarily have to be completely flat; they may also be approximately planar with slight curvature or approximately planar with slight irregularities.

[0031] (Implementation Method 1) In this embodiment, Figures 1 to 15 are used to illustrate a semiconductor device including an oxide semiconductor and a method for manufacturing the semiconductor device.

[0032] <Examples of semiconductor device structures> Use Figures 1 through 4 to illustrate examples of the structure of a semiconductor device. Figures 1A to 1D These are plan and cross-sectional views of a semiconductor device (transistor 200). Figure 1A This is a plan view of the semiconductor device. Additionally, Figures 1B to 1D This is a cross-sectional view of the semiconductor device. Here, Figure 1B It is along Figure 1A The cross-sectional view of the section marked with dotted lines A1-A2 is also a cross-sectional view along the channel length of transistor 200. Furthermore, Figure 1C It is along Figure 1A The cross-sectional view of the section marked with dotted lines A3-A4 is also a cross-sectional view of the channel width direction of transistor 200. Additionally, Figure 1D It is along Figure 1A The cross-sectional view of the section marked with dotted lines A5-A6 is also a cross-sectional view of the channel width direction of transistor 200. Note that in Figure 1A In the plan view, for clarity, some constituent elements have been omitted. Additionally, Figure 2A and Figure 2BThis is a cross-sectional view of transistor 200 and its surrounding wiring, which is related to... Figure 1B A cross-sectional view along the channel length of the same transistor 200. Additionally, Figures 3A to 4B This is an enlarged cross-sectional view of the transistor 200 along its channel length.

[0033] Transistor 200 includes a conductor 205 disposed in an insulator 216, an insulator 216 and an insulator 221 on the conductor 205, an insulator 222 on the insulator 221, an insulator 224 on the insulator 222, an oxide 230 on the insulator 224, conductors 242a and 242b on the oxide 230, an insulator 271a on the conductor 242a, an insulator 271b on the conductor 242b, an insulator 250 on the oxide 230 and a conductor 260 on the insulator 250.

[0034] Oxide 230 has a region serving as the channel formation region of transistor 200. Furthermore, conductor 260 has a region serving as the first gate electrode (also referred to as the upper gate electrode, top gate electrode) of transistor 200. Insulator 250 has a region serving as the first gate insulator of transistor 200. Furthermore, conductor 205 has a region serving as the second gate electrode (also referred to as the lower gate electrode, bottom gate electrode) of transistor 200. Insulators 224, 222, and 221 each have a region serving as the second gate insulator of transistor 200. Conductor 242a has a region serving as one of the source and drain electrodes of transistor 200. Conductor 242b has a region serving as the other of the source and drain electrodes of transistor 200.

[0035] An insulator 275 is provided on insulators 271a and 271b, and an insulator 280 is provided on insulator 275. An insulator 250 and a conductor 260 are disposed inside openings provided in insulators 280 and 275. Furthermore, an insulator 282a is provided in contact with the top surface of insulator 280, the upper end of insulator 250, and the top surface of conductor 260. Furthermore, an insulator 282b is provided in contact with the top surface of insulator 282a. Note that insulators 282a and 282b are sometimes collectively referred to as insulator 282. Furthermore, an insulator 283 is provided on insulator 282b. Furthermore, an insulator 214 is provided below insulator 216 and conductor 205. Additionally, a 212 is provided below insulator 214. Insulators 212, 214, 280, 282, 283 and 285 are used as interlayer membranes.

[0036] An opening is formed in insulators 285, 283, 282, 280, 275, and 271a to reach conductor 242a. Conductor 240a and insulator 241a are disposed within this opening. Insulator 241a is disposed in contact with the sidewall of this opening, and conductor 240a is disposed inside insulator 241a. Furthermore, an opening is formed in insulators 285, 283, 282, 280, 275, and 271b to reach conductor 242b. Conductor 240b and insulator 241b are disposed within this opening. Insulator 241b is disposed in contact with the sidewall of this opening, and conductor 240b is disposed inside insulator 241b. Conductors 240a and 240b are used as through holes to connect wiring or other components disposed on transistor 200 to the source or drain of transistor 200.

[0037] In addition, such as Figure 2A As shown, a conductor 218 used for wiring can also be provided in the same layer as conductor 205. A conductor 217 used as a through hole can also be provided in contact with the bottom surface of conductor 218. A conductor 240c used as a through hole can also be provided in contact with the top surface of conductor 218. Similar to conductors 240a and 240b, conductor 240c is provided inside the opening formed in insulators 285, 283, 282, 280, 275, 222, and 221. Insulator 241c can also be provided in contact with the sidewall of the opening, and conductor 240c can be provided inside insulator 241c.

[0038] Furthermore, it is preferable to use a metal oxide (hereinafter also referred to as an oxide semiconductor) for oxide 230.

[0039] like Figure 3A As shown, oxide 230 may include oxide 230a on insulator 224 and oxide 230b on oxide 230a. When oxide 230a is included below oxide 230b, the diffusion of impurities from the structure formed below oxide 230a to oxide 230b can be suppressed. This can improve the crystallinity of oxide 230b.

[0040] exist Figure 3A The diagram shows an example of oxide 230 having a two-layer structure of oxide 230a and oxide 230b, but it is not limited to this. Oxide 230 may have a single-layer structure or a stacked structure of three or more layers.

[0041] The oxide 230 contains a channel forming region for the transistor 200, as well as a source region and a drain region disposed in a manner that clamps the channel forming region. At least a portion of the channel forming region overlaps with the conductor 260. The source region overlaps with the conductor 242a, and the drain region overlaps with the conductor 242b. Note that the source region and drain region can also be interchanged.

[0042] Because it has fewer oxygen vacancies or lower impurity concentrations compared to the source and drain regions, the channel formation region is a high-resistivity region with low carrier concentration. Therefore, the channel formation region can be considered an i-type (intrinsic) or essentially i-type region. Furthermore, due to the abundance of oxygen vacancies or the high concentration of impurities such as hydrogen, nitrogen, and metal elements, the source and drain regions are low-resistance regions with high carrier concentration. In other words, the source and drain regions are n-type regions (low-resistance regions) with higher carrier concentration compared to the channel formation region.

[0044] The preferred carrier concentration in the channel formation region is 1×10⁻⁶. 18 cm -3 Below, less than 1×10 17 cm -3 Less than 1×10 16 cm -3 Less than 1×10 15 cm -3 Less than 1×10 14 cm -3 Less than 1×10 13 cm -3 Less than 1×10 12 cm -3 Less than 1×10 11 cm -3 Or less than 1×10 10 cm -3 Note that there is no specific limit to the lower limit of carrier concentration in the channel formation region; for example, it can be 1 × 10⁻⁶. -9 cm -3 .

[0045] When the aim is to reduce the carrier concentration of oxide 230, the impurity concentration in oxide 230 can be reduced to decrease the defect state density. In this specification and the like, a state with low impurity concentration and low defect state density is referred to as high-purity intrinsic or substantially high-purity intrinsic. Furthermore, oxide semiconductors (or metal oxides) with low carrier concentration are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors (or metal oxides).

[0046] Therefore, in order to stabilize the electrical characteristics of the transistor 200, it is effective to reduce the impurity concentration in the channel formation region of the oxide 230. To further reduce the impurity concentration in the channel formation region of the oxide 230, it is preferable to also reduce the impurity concentration in the nearby film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon. Note that impurities in the oxide 230 refer, for example, to elements other than the main components constituting the oxide 230. For example, elements with a concentration less than 0.1 atomic percent can be considered impurities.

[0047] In addition, the channel formation region, source region and drain region can be formed not only in oxide 230b but also in oxide 230a.

[0048] In oxide 230, it is sometimes difficult to clearly observe the boundaries between regions. The concentrations of metallic elements and impurity elements such as hydrogen and nitrogen detected in each region do not need to vary in stages according to each region; they can vary continuously within each region. That is, the closer to the channel formation region, the lower the concentration of metallic elements and impurity elements such as hydrogen and nitrogen can be.

[0049] In oxide 230, the bandgap of the oxide semiconductor is preferably 2 eV or more, more preferably 2.5 eV or more. By using a metal oxide with a wider bandgap, the off-state current of the transistor can be reduced. A transistor that thus includes a metal oxide in the channel formation region is called an OS transistor. OS transistors have low off-state currents, so the power consumption of semiconductor devices can be significantly reduced. In addition, OS transistors have high frequency characteristics, so semiconductor devices can operate at high speeds.

[0050] Oxide 230 preferably comprises a metal oxide (oxide semiconductor). Examples of metal oxides suitable for use in oxide 230 include indium oxide, gallium oxide, and zinc oxide. The metal oxide preferably comprises at least indium (In) or zinc (Zn). The metal oxide preferably comprises two or three elements selected from indium, element M, and zinc. Furthermore, element M is a metallic or metalloid element with a high bond energy with oxygen, for example, a metallic or metalloid element with a higher bond energy with oxygen than indium. Specifically, examples of element M include aluminum, gallium, tin, yttrium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zirconium, molybdenum, hafnium, tantalum, tungsten, lanthanum, cerium, neodymium, magnesium, calcium, strontium, barium, boron, silicon, germanium, and antimony. The element M included in the metal oxide is preferably any one or more of the above elements, more preferably one or more selected from aluminum, gallium, tin, and yttrium, and even more preferably gallium. In addition, in this specification and the like, metallic elements and metalloid elements are sometimes collectively referred to as "metallic elements", and the "metallic elements" described in this specification and the like sometimes include metalloid elements.

[0051] Oxide 230 can be, for example, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium gallium oxide (In-Ga oxide), indium gallium aluminum oxide (In-Ga-Al oxide), indium gallium tin oxide (In-Ga-Sn oxide), gallium zinc oxide (Ga-Zn oxide, also denoted as GZO), aluminum zinc oxide (Al-Zn oxide, also denoted as AZO), indium aluminum zinc oxide (In-Al-Zn oxide, also denoted as IAZO), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium zinc oxide (In-Ga-Zn oxide, also denoted as IGZO), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide, also denoted as IGZTO), indium gallium aluminum zinc oxide (In-Ga-Al-Zn oxide, also denoted as IGAZO or IAGZO), etc. Alternatively, silicon-containing indium tin oxide, gallium tin oxide (Ga-Sn oxide), aluminum tin oxide (Al-Sn oxide), etc., can be used.

[0052] At this point, the field-effect mobility of the transistor can be improved by increasing the ratio of indium atoms contained in the metal oxide relative to the sum of the number of atoms of all metal elements.

[0053] In addition, metal oxides can replace indium or contain one or more metal elements with high period numbers besides indium. The greater the orbital overlap of the metal elements, the greater the carrier conduction in the metal oxide. Therefore, by including metal elements with high period numbers, the field-effect mobility of transistors can sometimes be improved. Examples of metal elements with high period numbers include those belonging to the 5th period and those belonging to the 6th period. Specifically, examples of such metal elements include: yttrium, zirconium, silver, cadmium, tin, antimony, barium, lead, bismuth, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium. Furthermore, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium are called light rare earth elements.

[0054] In addition, metal oxides can also contain one or more non-metallic elements. When metal oxides contain non-metallic elements, the field-effect mobility of transistors can sometimes be improved. Examples of non-metallic elements include carbon, nitrogen, phosphorus, sulfur, selenium, fluorine, chlorine, bromine, and hydrogen.

[0055] Furthermore, by increasing the ratio of zinc atoms in the metal oxide to the total number of atoms of all metal elements, the crystallinity of the metal oxide is improved, thereby suppressing the diffusion of impurities in the metal oxide. Consequently, variations in the electrical characteristics of the transistor are suppressed, thus improving reliability.

[0056] Furthermore, by increasing the atomic ratio of element M, which is relative to the total number of atoms of all metal elements contained in the metal oxide, the formation of oxygen vacancies in the metal oxide can be suppressed. Therefore, the generation of charge carriers arising from oxygen vacancies is suppressed, thereby enabling transistors with low off-state currents. Additionally, variations in the electrical characteristics of the transistor are suppressed, thereby improving reliability.

[0057] As described above, the electrical characteristics and reliability of the transistor vary depending on the composition of the metal oxide used for oxide 230. Therefore, by varying the composition of the metal oxide to correspond to the required electrical characteristics and reliability of the transistor, a semiconductor device with both excellent electrical characteristics and high reliability can be realized.

[0058] Oxide 230 preferably has a stacked structure of multiple oxide layers with different chemical compositions. For example, the atomic ratio of element M relative to the main metal element in the metal oxide of oxide 230a is preferably greater than that in the metal oxide of oxide 230b. Furthermore, the atomic ratio of element M relative to In in the metal oxide of oxide 230a is preferably greater than that in the metal oxide of oxide 230b. By employing this structure, the diffusion of impurities and oxygen from the structure formed beneath oxide 230a to oxide 230b can be suppressed.

[0059] Furthermore, preferably, the ratio of the number of In atoms relative to element M in the metal oxide used for oxide 230b is greater than the ratio of the number of In atoms relative to element M in the metal oxide used for oxide 230a. By employing this structure, transistor 200 can achieve large on-state current and high frequency characteristics.

[0060] Furthermore, oxides 230a and 230b contain common elements as their main components besides oxygen, which can reduce the defect state density at the interface between oxides 230a and 230b. This reduces the impact of interface scattering on carrier conduction, thus enabling the transistor 200 to achieve a large on-state current and high frequency characteristics.

[0061] Specifically, oxide 230a can be a metal oxide with an In:M:Zn ratio of 1:3:2 or similar, an In:M:Zn ratio of 1:3:4 or similar, or an In:M:Zn ratio of 1:1:0.5 or similar. Furthermore, oxide 230b can be a metal oxide with an In:M:Zn ratio of 1:1:1 or similar, an In:M:Zn ratio of 1:1:1.2 or similar, an In:M:Zn ratio of 1:1:2 or similar, or an In:M:Zn ratio of 4:2:3 or similar. Note that "similar" includes a range of ±30% of the desired atomic ratio. Additionally, gallium is preferably used as element M.

[0062] Furthermore, oxides 230a and 230b may not contain element M. For example, the metal oxide used as oxide 230b may be an In-Zn oxide. Specifically, oxide 230b may have an In:Zn ratio of 1:1 or similar, or an In:Zn ratio of 4:1 or similar. Alternatively, indium oxide may be used as oxide 230b. Furthermore, the aforementioned oxide 230b may also contain trace amounts of element M. For example, specifically, oxide 230b may have an In:Sn:Zn ratio of 4:0.1:1 or similar.

[0063] Furthermore, when oxide 230 has a monolayer structure, any of the metal oxides described above that can be used for oxide 230a or oxide 230b can be used. Moreover, the composition of the metal oxides that can be used for oxides 230a and 230b is not limited thereto. For example, the composition of the metal oxide that can be used for oxide 230a can also be applied to oxide 230b. Similarly, the composition of the metal oxide that can be used for oxide 230b can also be applied to oxide 230a.

[0064] Furthermore, when depositing metal oxides using sputtering, the aforementioned atomic ratio is not limited to the atomic ratio of the deposited metal oxide, but can also be the atomic ratio of the sputtering target used for depositing the metal oxide.

[0065] For the analysis of the composition of the metal oxide used in oxide 230, methods such as energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectrometry (XPS), inductively coupled plasma mass spectrometry (ICP-MS), or inductively coupled plasma atomic emission spectrometry (ICP-AES) can be used. Alternatively, multiple methods can be combined. Note that the actual content of elements with low concentrations may differ from the analytically obtained content due to the limitations of analytical precision. For example, when the content of element M is low, the analytically obtained content of element M may sometimes be lower than the actual content.

[0066] Oxide 230 (especially oxide 230b) preferably has crystallinity. In particular, CAAC-OS (c-axis aligned crystalline oxide semiconductor) is preferably used as oxide 230.

[0067] CAAC-OS possesses a highly crystalline, dense structure and is a metal oxide with few impurities and defects (e.g., oxygen vacancies). In particular, by heat-treating CAAC-OS after its formation at a temperature at which polymorphism is not achieved (e.g., above 400°C and below 600°C), an even more crystalline, dense structure can be formed. Thus, by further increasing the density of CAAC-OS, the diffusion of impurities or oxygen within it can be further reduced.

[0068] Furthermore, distinct grain boundaries are not readily observed in CAAC-OS, thus reducing the likelihood of decreased electron mobility due to grain boundaries. Consequently, metal oxides containing CAAC-OS exhibit stable physical properties. Therefore, metal oxides containing CAAC-OS demonstrate high heat resistance and reliability.

[0069] Furthermore, by using a crystalline oxide such as CAAC-OS as oxide 230, oxygen extraction from the source or drain electrode can be suppressed. Therefore, even with heat treatment, oxygen extraction from oxide 230 can be reduced, making the transistor 200 stable even at high temperatures (so-called thermal budget) during the manufacturing process.

[0070] In transistors using oxide semiconductors, the presence of impurities and oxygen vacancies in the channel region of the oxide semiconductor can easily alter electrical characteristics, sometimes reducing reliability. Furthermore, hydrogen near the oxygen vacancy forms a defect where hydrogen enters the oxygen vacancy (sometimes referred to below as V). O H) may generate electrons that become charge carriers. Therefore, when oxygen vacancies are included in the channel formation region of an oxide semiconductor, the transistor will have always-on characteristics (the characteristic that current flows through the transistor even when no voltage is applied to the gate electrode). Therefore, in the channel formation region of an oxide semiconductor, it is preferable to minimize impurities, oxygen vacancies, and V O H. In other words, preferably, the carrier concentration in the channel formation region of the oxide semiconductor is reduced and is i-typed (intrinsicized) or substantially i-typed.

[0071] In contrast, by performing heat treatment with an insulator containing oxygen that is removed by heating (hereinafter, sometimes referred to as excess oxygen) near the oxide semiconductor, oxygen can be supplied to the oxide semiconductor from the insulator, thereby reducing oxygen vacancies and V. O H. Note that supplying excessive oxygen to the source or drain regions may cause a decrease in the on-state current or field-effect mobility of the transistor 200. Furthermore, if the amount of oxygen supplied to the source or drain regions is uneven within the substrate surface, the characteristics of the semiconductor device, including the transistor, will become uneven. Additionally, excessive oxygen supplied from the insulator to the oxide semiconductor can sometimes negatively impact the electrical characteristics and reliability of the transistor. Moreover, there is the concern that oxygen diffuses into the gate, source, and drain electrodes, causing oxidation and a decrease in conductivity.

[0072] Preferably, an insulator with hydrogen-barrier properties is first formed near transistor 200 to reduce the channel formation region of oxide 230 and its vicinity. O H.

[0073] At least one of insulators 212, 214, 221, 222, 275, 282a, 282b, and 283 is preferably used as a hydrogen-barrier insulator. Furthermore, at least one of insulators 212, 214, 221, 222, 275, 282a, 282b, and 283 is preferably used as an impurity-barrier insulator. Additionally, at least one of insulators 212, 214, 221, 222, 275, 282a, 282b, and 283 is preferably used as an oxygen-barrier insulator. Note that it is not necessary to provide all of insulators 212, 214, 221, 222, 275, 282a, 282b, and 283. As long as it provides sufficient barrier properties against hydrogen, impurities, oxygen, etc., it can be formed by appropriately selecting from insulators 212, 214, 221, 222, 275, 282a, 282b, and 283. For example, it is also possible to form a structure where insulator 216 and conductor 205 are in contact with the top surface of insulator 212 without insulator 214.

[0074] Note that in this specification, etc., "barrier insulator" refers to an insulator that has barrier properties. In this specification, "barrier property" means the property that the corresponding substance does not easily diffuse (also referred to as the property that the corresponding substance is not easily permeable, the property that the corresponding substance has low permeability, or the function of inhibiting the diffusion of the corresponding substance). Alternatively, it refers to the function of trapping or fixing the corresponding substance within the insulator (also called gettering). Furthermore, hydrogen, referred to as the corresponding substance, includes, for example, hydrogen atoms, hydrogen molecules, water molecules, and OH groups. - At least one of the following: substances bonded to hydrogen. Furthermore, unless otherwise specified, impurities referred to as corresponding substances refer to impurities in the channel-forming region or semiconductor layer, such as at least one of hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N₂O, NO, NO₂, etc.), copper atoms, etc. Additionally, oxygen referred to as corresponding substances refers to at least one of oxygen atoms, oxygen molecules, etc.

[0075] Silicon nitride or silicon oxynitride is preferred as an insulator that inhibits hydrogen diffusion. Other materials that may be used include, for example, aluminum oxide, magnesium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium (hafnium aluminate), oxides containing hafnium and zirconium (hafnium zirconium oxide), gallium oxide, and indium gallium zinc oxide.

[0076] Insulators 212, 221, 275, and 283 are preferably insulators that have the function of suppressing hydrogen diffusion. For example, silicon nitride with higher hydrogen barrier properties can be used for insulators 212, 221, 275, and 283.

[0077] As insulators capable of trapping or fixing hydrogen, metal oxides such as hafnium oxides, aluminum oxides, aluminum and hafnium oxides (hafnium aluminate), or magnesium oxide are preferred. Insulators capable of trapping or fixing hydrogen preferably have an amorphous structure. The aforementioned amorphous metal oxides sometimes possess the property that oxygen atoms have dangling bonds, which trap or fix hydrogen. That is, it can be said that amorphous metal oxides have a high ability to trap or fix hydrogen. By adding silicon to the aforementioned metal oxides, polymorphism can be suppressed, making amorphization easier to achieve. Therefore, metal oxides with added silicon (e.g., hafnium silicate, aluminum silicate, etc.) are preferred.

[0078] Insulators 214, 222, 282a, and 282b are preferably insulators that have the function of trapping or fixing hydrogen. For example, aluminum oxide can be used as insulator 214, insulator 282a, and insulator 282b. For example, hafnium oxide, which is a high-k material, is preferably used as insulator 222, which is used as the second gate insulator.

[0079] In addition, inorganic insulators, which are insulators that have the function of inhibiting hydrogen diffusion and insulators that have the function of capturing or fixing hydrogen, also have oxygen barrier properties.

[0080] like Figure 3A As shown, it is preferable to provide an insulator 212 with the function of suppressing hydrogen diffusion and an insulator 214 with the function of trapping or fixing hydrogen below the transistor 200. By providing the insulator 212 below the transistor 200, hydrogen diffusion from the lower layer of the transistor 200 can be suppressed. Furthermore, by providing the insulator 214 on the insulator 212, hydrogen contained in the insulator 216, etc., can be trapped or fixed by the insulator 214. As a result, the hydrogen concentration in and around the oxide 230 can be reduced.

[0081] In addition, such as Figure 3A As shown, it is preferable to provide an insulator 221 with the function of suppressing hydrogen diffusion and an insulator 222 with the function of trapping or fixing hydrogen below the transistor 200. By providing the insulator 221 below the transistor 200, hydrogen diffusion from the lower layer of the transistor 200 can be suppressed. Furthermore, by providing the insulator 222 on the insulator 221, hydrogen contained in the insulator 224, etc., can be trapped or fixed by the insulator 222. As a result, the hydrogen concentration in and around the oxide 230 can be reduced.

[0082] In addition, such as Figure 3A As shown, the insulator 275 is preferably provided in a manner that covers the oxide 230, conductor 242a, conductor 242b, etc. By providing the insulator 275 in this way, the diffusion of hydrogen from the insulator 280 to the oxide 230, conductor 242a, conductor 242b, etc. can be suppressed.

[0083] In addition, such as Figure 3A As shown, preferably, an insulator 282 with the function of trapping or fixing hydrogen and an insulator 283 with the function of suppressing hydrogen diffusion are provided on the transistor 200. By providing the insulator 283 on the transistor 200, hydrogen diffusion from the upper layer of the transistor 200 can be suppressed. Furthermore, by providing the insulator 282 below the insulator 283, hydrogen contained in the insulator 280, etc., can be trapped or fixed by the insulator 282. As a result, the hydrogen concentration in and around the oxide 230 can be reduced.

[0084] Thus, by employing a structure in which hydrogen barrier insulators surround the top and bottom of transistor 200, hydrogen diffusion into the oxide semiconductor can be reduced, thereby reducing Vc in the channel formation region. O H. This improves the electrical characteristics and reliability of transistor 200.

[0085] Furthermore, it is preferable that the insulator 280 contains oxygen that has been removed by heating. By supplying this oxygen to the oxide 230 through the insulator 250 using a heat treatment, oxygen vacancies in the channel forming region can be reduced.

[0086] In this embodiment, oxygen can be added to the insulator 280 by sputtering deposition of the insulator 282b in an atmosphere containing oxygen gas. Since the insulator 282b is deposited while the insulator 282a is already formed, and oxygen is added through the insulator 282a, the amount of oxygen added to the insulator 280 can be controlled. When the thickness of the insulator 282a is large, the oxygen addition is easily hindered, resulting in a decrease in the amount of oxygen injected into the insulator 280. When the thickness of the insulator 282a is small, the oxygen addition is less easily hindered, resulting in an increase in the amount of oxygen injected into the insulator 280. For example, by setting the thickness of the insulator 282a to 1 nm or more and 20 nm or less, preferably 3 nm or more and 10 nm or less, an appropriate amount of oxygen can be supplied to the insulator 280.

[0087] Furthermore, to prevent the addition of oxygen to the insulator 280 during the deposition of the insulator 282a, the insulator 282a is preferably deposited using atomic layer deposition (ALD). To reduce the thickness of the insulator 282a as described above, ALD deposition is preferred. ALD methods include thermal ALD, which uses only thermal energy to react the precursors and reactants, and plasma-enhanced ALD, which uses reactants excited by plasma.

[0088] The precursors used in the ALD method sometimes contain carbon and other impurities. Therefore, films formed using the ALD method sometimes contain more carbon and other impurities compared to films formed using other deposition methods. Consequently, the carbon concentration in insulator 282a is sometimes higher than that insulator 282b. Furthermore, impurity quantification can be performed using secondary ion mass spectrometry (SIMS), X-ray photoelectron spectroscopy (XPS), or Auger electron spectroscopy (AES).

[0089] For example, when both insulator 282a and insulator 282b contain alumina, the carbon concentration of insulator 282a is sometimes higher than that of insulator 282b. In this case, the carbon concentration of insulator 282a in SIMS analysis is sometimes 1 × 10⁻⁶. 18 atoms / cm 3 Above and 1×10 21 atoms / cm 3 Below, and having 1×10 19 atoms / cm 3 Above and 1×10 21 atoms / cm 3 The following region. Furthermore, the carbon concentration of insulator 282b in SIMS analysis is sometimes above the detection limit and 1×10⁻⁶. 20 atoms / cm 3 Below, and has 4.46×10 17 atoms / cm 3 Above and 1×10 19 atoms / cm 3 The following areas.

[0090] As described above, by heating the insulator 280, which contains oxygen released through heating, an appropriate amount of oxygen can be supplied to the oxide 230 via the insulator 250. During this heating process, since oxygen-barrier insulators 282 and 283 are formed on the insulator 280, excessive diffusion of oxygen contained in the insulator 280 from the insulator 280 is prevented. Furthermore, since an oxygen-barrier insulator 275 is formed between the insulator 280 and the oxide 230, conductors 242a and 242b, excessive diffusion of oxygen contained in the insulator 280 from the insulator 280 is also prevented. Moreover, by performing this heating process with openings formed in a portion of the insulators 280, 282, and 283, a portion of the oxygen contained in the insulator 280 can diffuse outwards, thereby adjusting the amount of oxygen supplied from the insulator 280 to the oxide 230. Here, the insulator 250 preferably has a structure that allows oxygen to diffuse from the insulator 280 to the oxide 230 and suppresses the oxidation of the conductors 242a, 242b and 260.

[0092] like Figure 1B and Figure 1C As shown, insulator 250 is disposed within an opening formed in insulator 280 and insulator 275. Within this opening, insulator 250 is formed in contact with the top surface of insulator 222, the side surface of insulator 224, the side surface and top surface of oxide 230b, the side surface of conductor 242a, the side surface of conductor 242b, the side surface of insulator 271a, the side surface of insulator 271b, the side surface of insulator 275, and the side surface of insulator 280.

[0093] Here, as Figure 3A As shown, the insulator 250 preferably has a stacked structure of an insulator 250a in contact with the oxide 230, an insulator 250b on the insulator 250a, and an insulator 250c on the insulator 250b.

[0094] Insulator 250b is preferably made of silicon oxide or silicon oxynitride, which have high dielectric withstand voltage. Furthermore, to improve dielectric withstand voltage, the thickness of insulator 250b can be greater than the thickness of insulators 250a and 250d. By using the aforementioned oxide insulator, oxygen can be diffused into insulator 250b through high-temperature heat treatment. Therefore, by performing heat treatment, oxygen contained in insulator 280 can be supplied to oxide 230 via insulator 250b. Note that in this specification, "oxynitride" refers to a material in which the oxygen content is greater than the nitrogen content, while "oxygen oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, "silicon oxynitride" refers to a material in which the oxygen content is greater than the nitrogen content, while "silicon oxynitride" refers to a material in which the nitrogen content is greater than the oxygen content.

[0095] Furthermore, in order to suppress the oxidation of conductors 242a, 242b, and 260, it is preferable to provide an oxygen barrier insulator near each of conductors 242a, 242b, and 260. For example, it is preferable to provide an oxygen barrier insulator as insulator 250a and insulator 250c. Insulator 250a preferably has oxygen-barrier properties. Insulator 250a is preferably at least less permeable to oxygen than insulator 250b. Insulator 250a has regions that contact the sides of conductor 242a and the sides of conductor 242b. When insulator 250a has oxygen-barrier properties, oxidation of the sides of conductors 242a and 242b, resulting in the formation of an oxide film on those sides, can be suppressed. Therefore, a decrease in the on-state current or field-effect mobility of transistor 200 can be suppressed. Furthermore, by employing this structure, the amount of oxygen absorbed by conductors 242a and 242b in insulator 250b can be reduced. Therefore, an appropriate amount of oxygen can be supplied from insulator 250b to oxide 230, thereby reducing oxygen vacancies in the channel formation region of oxide 230.

[0097] Furthermore, by providing insulator 250a between insulator 280 and insulator 250b, and between insulator 250b and oxide 230, excessive oxygen supply from insulator 280 to oxide 230 can be suppressed, and an appropriate amount of oxygen can be supplied to oxide 230. Therefore, the oxygen content in and around the channel formation region of oxide 230 can be controlled to an appropriate level, thus preventing excessive normally-off operation of transistor 200 and improving reliability. In addition, excessive oxidation of the source and drain regions can be suppressed, preventing a decrease in the on-state current or field-effect mobility of transistor 200.

[0098] Therefore, the thickness of the insulator 250a is preferably such that it does not excessively impede the diffusion of oxygen from the insulator 280 to the insulator 250b and from the insulator 250b to the oxide 230. For example, the thickness of the insulator 250a is preferably 0.1 nm or more and 5.0 nm or less, more preferably 0.5 nm or more and 5.0 nm or less, further preferably 0.5 nm or more and less than 3.0 nm, and even more preferably 0.5 nm or more and 2.0 nm or less.

[0099] As described above, it is preferable to appropriately diffuse oxygen from insulator 280 to insulator 250b and from insulator 250b to oxide 230, while suppressing oxygen diffusion from insulator 250b to conductors 242a and 242b as much as possible. Here, in the semiconductor device according to this embodiment, the contact area between insulator 250a and conductor 242a and the contact area between insulator 250a and conductor 242b are much smaller than the contact area between insulator 250a and oxide 230. That is, it can be inferred that the amount of oxygen diffusing from insulator 250b through insulator 250a to conductors 242a and 242b is less than the amount of oxygen diffusing from insulator 250b through insulator 250a to oxide 230. Therefore, by controlling the amount of oxygen contained in the insulator 280 to supply an appropriate amount of oxygen from the insulator 280 to the insulator 250b and the oxide 230, the oxidation of the conductors 242a and 242b can be reduced.

[0100] The insulator 250a in contact with the channel-forming region in oxide 230 preferably has the function of trapping or fixing hydrogen. This reduces the hydrogen concentration in the channel-forming region of oxide 230. Therefore, the Vg in the channel-forming region can be reduced. O H causes the channel to form an i-shaped region or essentially an i-shaped region.

[0101] Furthermore, the insulator 250a is preferably made of a high-k material. An example of a high-k material is an oxide containing one or both of aluminum and hafnium. When a high-k material is used as the insulator 250a, the gate potential applied during transistor operation can be reduced while maintaining the physical thickness of the gate insulator. Additionally, the equivalent oxide thickness (EOT) of the insulator used as the gate insulator can be reduced.

[0102] Therefore, as the insulator 250a, an oxide containing one or both of aluminum and hafnium is preferred, and an oxide having an amorphous structure and containing one or both of aluminum and hafnium is more preferred. Since alumina can be easily deposited into an amorphous film using the ALD method, alumina having an amorphous structure is further preferred. In this embodiment, an alumina film is used as the insulator 250a. Alumina has the function of trapping or fixing hydrogen and has oxygen-blocking properties, so it can be suitably used as the insulator 250a.

[0103] The insulator 250c preferably also has oxygen-barrier properties. The insulator 250c is disposed between the channel formation region of the oxide 230 and the conductor 260, and between the insulator 280 and the conductor 260. By employing this structure, the diffusion of oxygen from the channel formation region of the oxide 230 to the conductor 260, thus preventing the formation of oxygen vacancies in the channel formation region of the oxide 230, can be suppressed. Furthermore, the diffusion of oxygen from the oxide 230 and the insulator 280 to the conductor 260, thus preventing oxidation of the conductor 260, can be suppressed. The insulator 250c is preferably at least less permeable to oxygen than the insulator 250b. In addition, the insulator 250c preferably has the function of suppressing hydrogen diffusion. Thus, impurities such as hydrogen contained in the conductor 260 can be prevented from diffusing into the oxide 230. For example, a silicon nitride film is preferably used as the insulator 250c.

[0104] In addition, such as Figure 3B As shown, a structure in which insulator 250d is provided on insulator 250b can also be adopted. In this case, an insulator that can also be used as insulator 250a can be provided as insulator 250d. For example, hafnium oxide can be used as insulator 250d. Here, by providing insulator 250d between insulator 250c and insulator 250b, hydrogen contained in insulator 250b and the like can be captured and fixed more effectively.

[0105] By adopting the above structure, the channel formation region can be i-type or substantially i-type, and the source and drain regions can be n-type, providing a semiconductor device with excellent electrical characteristics. By adopting the above structure, even when the semiconductor device is miniaturized or highly integrated, it can still possess excellent electrical characteristics. Furthermore, miniaturizing the transistor 200 can improve frequency characteristics. Specifically, the cutoff frequency can be increased.

[0106] Insulators 250a to 250d are used as part of the first gate insulator. Insulators 250a to 250d are disposed together with conductor 260 in an opening formed in insulator 280. To achieve miniaturization of transistor 200, the thickness of insulators 250a, 250c, and 250d is preferably small. The thickness of insulators 250a, 250c, and 250d is preferably 0.1 nm or more and 20 nm or less, more preferably 0.1 nm or more and 10 nm or less, further preferably 0.5 nm or more and 5.0 nm or less, even more preferably 1.0 nm or more and less than 5.0 nm, and even more preferably 1.0 nm or more and 3.0 nm or less. Furthermore, at least a portion of insulators 250a, 250c, and 250d may include regions with the thicknesses described above.

[0107] In order to reduce the thickness of insulators 250a to 250d as described above, it is preferable to perform deposition using the ALD method. Furthermore, in order to form insulators 250a to 250d with high coverage within the openings of insulators 280, etc., it is preferable to deposit insulators 250a to 250d using the ALD method.

[0108] Note that while the insulator 250 is described above as having a three-layer structure of insulators 250a to 250c or a four-layer structure of insulators 250a to 250d, the present invention is not limited thereto. The insulator 250 may have a structure including at least one of insulators 250a to 250d. By having the insulator 250 comprised of one, two, or three layers of insulators 250a to 250d, the manufacturing process of semiconductor devices can be simplified, thereby improving productivity.

[0109] In transistor 200, conductor 205 is arranged to overlap with oxide 230 and conductor 260. Conductive materials described in "Conductors" can be used as conductor 205. Here, conductor 205 is preferably provided in a manner that embeds it in an opening formed in insulator 216. Furthermore, as... Figure 1A and Figure 1C As shown, the conductor 205 preferably extends in the channel width direction. By employing this structure, the conductor 205 is used as wiring when multiple transistors are arranged.

[0110] like Figure 3A As shown, conductor 205 preferably includes conductor 205a and conductor 205b. Conductor 205a is disposed in contact with the bottom surface and sidewall of the opening. Conductor 205b is disposed in a recess of conductor 205a formed along the opening. Here, the height of the top surface of conductor 205 is the same as or approximately the same as the height of the top surface of insulator 216.

[0111] Here, the conductor 205a preferably comprises a conductive material that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms. Alternatively, it is preferable to include a conductive material that has the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.).

[0112] By using a conductive material that reduces hydrogen diffusion as conductor 205a, impurities such as hydrogen contained in conductor 205b can be prevented from diffusing to oxide 230 through insulator 216, etc. Furthermore, by using a conductive material that inhibits oxygen diffusion as conductor 205a, oxidation of conductor 205b and subsequent decrease in conductivity can be prevented. Examples of conductive materials that inhibit oxygen diffusion include titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, and ruthenium oxide. Conductor 205a can have a single-layer structure or a multilayer structure of the aforementioned conductive materials. For example, conductor 205a preferably contains titanium nitride.

[0113] Furthermore, the conductor 205b preferably uses a conductive material whose main component is tungsten, copper, or aluminum. For example, the conductor 205b preferably contains tungsten. Conductor 205 can be used as a second gate electrode. In this case, the threshold voltage (Vth) of transistor 200 can be controlled by independently changing the potential applied to conductor 205 without linking it to the potential applied to conductor 260. In particular, by applying a negative potential to conductor 205, the Vth of transistor 200 can be further increased, thereby reducing the off-state current. Thus, compared to not applying a negative potential to conductor 205, applying a negative potential to conductor 205 can reduce the drain current when the potential applied to conductor 260 is 0V.

[0115] Furthermore, the resistivity of the conductor 205 is designed taking into account the potential applied to the conductor 205 as described above, and the thickness of the conductor 205 is set according to this resistivity. Additionally, the thickness of the insulator 216 is approximately the same as that of the conductor 205. Here, it is preferable to reduce the thickness of both the conductor 205 and the insulator 216 within the design limits of the conductor 205. By reducing the thickness of the insulator 216, the absolute amount of impurities such as hydrogen contained in the insulator 216 can be reduced, thus suppressing the diffusion of these impurities into the oxide 230.

[0116] Note that in Figure 3A The diagram shows a stacked structure of conductors 205a and 205b, but the invention is not limited thereto; conductor 205 can have a single-layer structure or a stacked structure of three or more layers. For example, as shown... Figure 4AAs shown, a three-layer structure including conductor 205a, conductor 205b, and conductor 205c can also be used. Here, conductor 205c is disposed below conductor 205a and formed along the opening of insulator 216. Conductor 205c is preferably made of tantalum or tantalum nitride, for example. By adopting this structure, the diffusion of impurities such as hydrogen and metallic impurities such as copper contained in the lower layer of transistor 200 to conductor 205 can be suppressed.

[0117] In addition, for example, such as Figure 4B As shown, a four-layer structure including conductor 205a, conductor 205b, conductor 205c, and conductor 205d can also be used. Here, conductor 205d is disposed on conductor 205b and contacts the top surface of conductor 205b and a portion of the side surface of conductor 205a. Conductor 205c can be made of a conductive material suitable for conductor 205a. By forming conductor 205d, even if the top surface of conductor 205b is lower than the uppermost part of conductor 205a, the recess formed by conductors 205a and 205b can be filled. Furthermore, even if a recess is formed in the center of the top surface of conductor 205b, that recess can be filled. Therefore, the flatness of the top surface of conductor 205 can be improved.

[0118] Furthermore, similar to conductor 205, conductor 218 is preferably disposed in a manner that is embedded in the opening formed in insulator 216. Here, conductor 217 is disposed in such a manner that it contacts the bottom surface of conductor 218. Conductor 217 is disposed in a manner that is embedded in insulator 212 and insulator 214. Furthermore, as Figure 2B As shown, the top of the conductor 217 can also be formed in a way that protrudes from the top surface of the insulator 214. In this case, the top of the conductor 217 is embedded in a part of the conductor 218.

[0119] The conductor 218 is preferably formed in parallel with the conductor 205, in which case the conductor 218 has the same layer structure as the conductor 205. For example, as Figure 4A As shown, when conductor 205 includes conductor 205a, conductor 205b, and conductor 205c, conductor 218 includes conductor 218a, conductor 218b, and conductor 218c. Similar to conductor 205c, tantalum or tantalum nitride is preferably used as conductor 218c. By employing this structure, even if impurities such as hydrogen and metallic impurities such as copper contained in the lower layer of transistor 200 diffuse through conductor 217, these impurities can be blocked by conductor 218c.

[0120] In addition, such as Figure 4AAs shown, the conductor 217 can also have a laminated structure. In this case, the conductor 217 includes a conductor 217a disposed along the sidewall of the opening of the insulator 212 and the insulator 214, and a conductor 217b inside the conductor 217a. The conductor 217a can be made of a conductive material that can be used for the conductor 205a. Furthermore, the conductor 217b can be made of a conductive material that can be used for the conductor 205b.

[0121] Insulators 224, 221 and 222 are used as the second gate insulator.

[0122] The insulator 224 in contact with the oxide 230 preferably comprises, for example, silicon oxide or silicon oxynitride. This allows oxygen to be supplied from the insulator 224 to the oxide 230, reducing oxygen vacancies. Furthermore, the insulator 224 may also have a multilayer structure with two or more layers. In this case, it is not limited to a multilayer structure made of the same material; a multilayer structure made of different materials can also be used.

[0123] Furthermore, the insulator 224 is preferably processed into an island shape in the same way as the oxide 230. Thus, when multiple transistors 200 are provided, each transistor 200 includes an insulator 224 of approximately the same size. Therefore, the amount of oxygen supplied from the insulator 224 to the oxide 230 in each transistor 200 is approximately equal. This suppresses non-uniformity in the electrical characteristics of the transistors 200 within the substrate surface.

[0124] Note that insulator 224 does not necessarily have to be machined into an island shape. For example, as Figures 5A to 5D As shown, the insulator 224 can also be partially formed into an open shape instead of being an island. Here, Figures 5A to 5D Corresponding to Figures 1A to 1D Apart from the difference in shape of insulator 224, it is similar to Figures 1A to 1D same.

[0125] exist Figures 5A to 5D In the insulator 224 shown, the thickness of the region that does not overlap with the oxide 230 is smaller than the thickness of the region that overlaps with the oxide 230. Furthermore, openings are formed in the region that does not overlap with the oxide 230 but overlaps with the insulator 250. When multiple transistors are disposed on the same substrate, by forming the insulator 224 in this way, the oxide 230 of each transistor is formed on the same insulator 224. This reduces the non-uniformity of the oxygen content in the oxide 230 supplied from the insulator 224 to each transistor. Therefore, the non-uniformity of the electrical characteristics of each transistor can be reduced.

[0126] Note that in Figures 5A to 5D In the insulator 224 shown, an opening is formed in the region that does not overlap with the oxide 230 but overlaps with the insulator 250, but this opening may not be provided.

[0127] Conductive materials described in the "Conductors" manual can be used as conductors 242a, 242b, and 260. In particular, conductive materials that are not easily oxidized or that have the function of inhibiting oxygen diffusion are preferably used as conductors 242a, 242b, and 260. Examples of such conductive materials include nitrogen-containing conductive materials and oxygen-containing conductive materials. This helps to suppress the decrease in conductivity of conductors 242a, 242b, and 260. When conductive materials containing metals and nitrogen are used as conductors 242a, 242b, and 260, conductors 242a, 242b, and 260 are conductors that contain at least metals and nitrogen.

[0128] Metal nitrides are preferably used as conductors 242a and 242b. For example, nitrides containing tantalum, titanium, molybdenum, tungsten, tantalum and aluminum, or titanium and aluminum are preferred. For instance, tantalum nitride can be used as conductors 242a and 242b. Furthermore, ruthenium, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel can also be used. These materials are preferred because they are conductive materials that are not easily oxidized or maintain conductivity even after absorbing oxygen.

[0129] Note that sometimes hydrogen contained in oxide 230, etc., diffuses into conductor 242a or conductor 242b. In particular, when a tantalum-containing nitride is used as conductor 242a and conductor 242b, sometimes hydrogen contained in oxide 230, etc., readily diffuses into conductor 242a or conductor 242b, and sometimes this diffused hydrogen bonds with the nitrogen contained in conductor 242a or conductor 242b. That is, sometimes hydrogen contained in oxide 230, etc., is absorbed by conductor 242a or conductor 242b.

[0130] Furthermore, conductors 242a and 242b may also have a stacked structure. In this case, the aforementioned conductive material can be used as the lower layer of conductors 242a and 242b, while a conductive material with higher conductivity can be used as the upper layer. For example, tantalum nitride can be used as the lower layer, and tungsten can be used as the upper layer.

[0131] Insulators 271a and 271b are inorganic insulators used as etch stop layers to protect conductors 242a and 242b during the processing of conductors 242a and 242b. Furthermore, since they are in contact with conductors 242a and 242b, insulators 271a and 271b are preferably made of inorganic insulators that do not easily oxidize conductors 242a and 242b. Therefore, as... Figure 3A As shown, preferably, insulator 271a has a stacked structure of insulator 271a1 and insulator 271a2 on insulator 271a1, and insulator 271b has a stacked structure of insulator 271b1 and insulator 271b2 on insulator 271b1. Here, insulator 271a1 and insulator 271b1 preferably use nitride insulators suitable for insulator 250c to prevent oxidation of conductors 242a and conductor 242b. Furthermore, for use as an etch stop layer, insulator 271a2 and insulator 271b2 preferably use oxide insulators suitable for insulator 250b.

[0132] Here, insulator 271a1 contacts the top surface of conductor 242a and a portion of insulator 275, and insulator 271b1 contacts the top surface of conductor 242b and a portion of insulator 275. Additionally, insulator 271a2 contacts the top surface of insulator 271a1 and the bottom surface of insulator 275, and insulator 271b2 contacts the top surface of insulator 271b1 and the bottom surface of insulator 275. For example, silicon nitride can be used as insulator 271a1 and insulator 271b1, and silicon oxide can be used as insulator 271a2 and insulator 271b2.

[0133] The insulators that will become insulators 271a and 271b are used as masks for conductors that will become conductors 242a and 242b, therefore, as Figure 1D The conductors 242a and 242b shown do not have a curved surface between their side and top surfaces. Therefore, the ends where the side and top surfaces of conductors 242a and 242b intersect have sharp edges. When the ends where the side and top surfaces of conductors 242a and 242b intersect have sharp edges, the cross-sectional area of ​​conductors 242a and 242b is increased compared to the case where the ends have curved surfaces. Furthermore, by using nitride insulators that are not prone to metal oxidation as insulators 271a1 and 271b1, excessive oxidation of conductors 242a and 242b can be prevented. As a result, the resistance of conductors 242a and 242b is reduced, thus increasing the transistor's on-state current.

[0134] like Figure 1B and Figure 1C As shown, the conductor 260 is disposed in the openings formed in the insulators 280 and 275. The conductor 260 is disposed in the openings such that it covers the top surface of the insulator 222, the side surface of the insulator 224, and the side and top surfaces of the oxide 230b, separated by the insulator 250. Furthermore, the top surface of the conductor 260 is disposed at the same or substantially the same height as the upper end of the insulator 250 and the top surface of the insulator 280.

[0135] In the opening provided with conductor 260 and insulator 250, the sidewall of the opening can be perpendicular or substantially perpendicular to the top surface of insulator 222, or it can have a conical shape. By having a conical sidewall, the coverage of insulator 250 and the like provided in the opening of insulator 280 can be improved, thereby reducing defects such as voids.

[0136] Conductor 260 is used as the first gate electrode of transistor 200. Here, as... Figure 1A and Figure 1C As shown, the conductor 260 preferably extends in the channel width direction. By employing this structure, the conductor 260 is used as wiring when multiple transistors are arranged.

[0137] When the above structure is adopted, such as Figure 1C As shown, when viewed in cross-section along the channel width direction of transistor 200, a curved surface may also be present between the side surface and the top surface of oxide 230. That is, the ends of the side surface and the ends of the top surface may also be curved (hereinafter also referred to as circular).

[0138] The radius of curvature of the aforementioned curved surface is preferably greater than 0 nm and less than the thickness of the oxide 230 in the region overlapping with conductors 242a and 242b, or less than half the length of the region without the aforementioned curved surface. Specifically, the radius of curvature of the aforementioned curved surface is greater than 0 nm and less than 20 nm, preferably more than 1 nm and less than 15 nm, and more preferably more than 2 nm and less than 10 nm. By adopting the above shape, the coverage of the insulator 250 and conductor 260 on the oxide 230 can be improved. In this specification, the transistor structure in which at least the electric field of the first gate electrode forms a region surrounding the channel is referred to as a surrounded channel (S-channel) structure. Furthermore, the S-channel structure disclosed in this specification differs from Fin-type and planar structures. On the other hand, the S-channel structure disclosed in this specification can be considered a type of Fin-type structure. Additionally, in this specification, a Fin-type structure refers to a structure in which the gate electrode is arranged with at least two or more surfaces surrounding the channel (specifically, two, three, or four surfaces, etc.). By employing Fin-type and S-channel structures, tolerance to short-channel effects can be improved; in other words, transistors less prone to short-channel effects can be realized.

[0140] By employing the aforementioned S-channel structure in transistor 200, a region can be electrically formed around the channel. Since the S-channel structure is a structure that electrically forms a region around the channel, it can be said that this structure is essentially the same as a GAA (Gate All Around) structure or a LGAA (Lateral Gate All Around) structure. By giving transistor 200 an S-channel, GAA, or LGAA structure, the channel formation region formed at or near the interface between oxide 230 and the gate insulator can be considered as the entire bulk of oxide 230. Therefore, the current density flowing through the transistor can be increased, and thus an increase in the transistor's on-state current or field-effect mobility can be expected.

[0141] This embodiment employs an island-shaped structure for the insulator 224. Therefore, as... Figure 1C As shown, at least a portion of the bottom surface of the conductor 260 can be disposed below the bottom surface of the oxide 230. Therefore, the conductor 260 can be disposed opposite to the top and side surfaces of the oxide 230, allowing the electric field of the conductor 260 to act on the top and side surfaces of the oxide 230. Thus, by employing an island-shaped structure for the insulator 224, the transistor 200 can have an S-channel structure.

[0142] Note that, as Figure 1C The transistor 200 shown illustrates an S-channel structure, but the semiconductor device of one embodiment of the present invention is not limited thereto. For example, as a transistor structure that can be used in one embodiment of the present invention, one or more selected from planar structures, Fin structures, and GAA structures may also be employed.

[0143] like Figure 3A As shown, the conductor 260 preferably has a two-layer structure. Here, the conductor 260 preferably includes a conductor 260a and a conductor 260b disposed on the conductor 260a. For example, it is preferable that the conductor 260a is disposed in a manner that surrounds the bottom and side surfaces of the conductor 260b. In this case, as the conductor 260a, it is preferable to use a conductive material that is not easily oxidized or a conductive material that has the function of inhibiting oxygen diffusion.

[0144] The conductor 260a preferably uses a conductive material that has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules, and copper atoms. Furthermore, it is preferable to use a conductive material that has the function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.).

[0145] Furthermore, when the conductor 260a has the function of suppressing oxygen diffusion, it can prevent the oxygen contained in the insulator 280, etc., from oxidizing the conductor 260b and causing a decrease in conductivity. As a conductive material with the function of suppressing oxygen diffusion, titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, ruthenium oxide, etc. are preferred, for example.

[0146] Furthermore, the conductor 260b is preferably a conductor with high conductivity. For example, the conductor 260b can be a conductive material with tungsten, copper, or aluminum as the main component. In addition, the conductor 260b can have a laminated structure, for example, it can have a laminated structure of titanium or titanium nitride with the aforementioned conductive material.

[0147] Furthermore, in transistor 200, conductor 260 is formed in a self-aligned manner by filling the openings formed in insulator 280, etc. By forming conductor 260 in this way, conductor 260 can be arranged to overlap with the region between conductor 242a and conductor 242b without alignment.

[0148] The dielectric constants of insulators 216, 280, and 285 are preferably lower than those of insulator 222. By using materials with low dielectric constants for the interlayer films, parasitic capacitances generated between wirings can be reduced.

[0149] For example, insulators 216, 280, and 285 preferably comprise one or more of silicon oxide, silicon oxynitride, fluorine-added silicon oxide, carbon-added silicon oxide, carbon and nitrogen-added silicon oxide, and porous silicon oxide.

[0150] In particular, silicon oxide and silicon oxynitride are preferred due to their thermal stability. Especially, materials such as silicon oxide, silicon oxynitride, and porous silicon oxide are preferred because they readily form regions containing oxygen that has been released upon heating.

[0151] In addition, the top surfaces of insulators 216 and 280 can also be flattened.

[0152] The concentration of impurities such as water and hydrogen in the insulator 280 is preferably reduced. For example, silicon oxides such as silicon oxynitride are preferably used as the insulator 280.

[0153] Conductive materials described in "Conductors" can be used as conductors 240a, 240b, and 240c. Conductive materials with tungsten, copper, or aluminum as the main component are preferably used for conductors 240a, 240b, and 240c. Furthermore, conductors 240a and 240b may also have a laminated structure.

[0154] For example, such as Figure 3AAs shown, conductors 240a and 240b may also have a two-layer stacked structure. Conductor 240a includes conductor 240a1 formed along the opening and conductor 240a2 formed inside conductor 240a1. Furthermore, conductor 240b includes conductor 240b1 formed along the opening and conductor 240b2 formed inside conductor 240b1.

[0155] Similar to conductor 205a, conductors 240a1 and 240b1 preferably use conductive materials that suppress the permeation of impurities such as water and hydrogen. For example, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, and ruthenium oxide are preferred. Alternatively, a single layer or a stack of conductive materials that suppress the permeation of impurities such as water and hydrogen can be used. By providing conductors 240a1 and 240b1, impurities such as water and hydrogen can be prevented from mixing into oxide 230 through conductors 240a2 and 240b2. Furthermore, conductors 240a2 and 240b2 can use the aforementioned conductive materials applicable to conductors 240a, 240b, and 240c. Additionally, conductor 240c, like conductors 240a and 240b, can also have a stacked structure.

[0156] In addition, such as Figure 2A As shown, the top surfaces of conductors 240a, 240b, and 240c can be formed in a manner that aligns with or substantially aligns with the top surface of insulator 285. Furthermore, as... Figure 2B As shown, the lower portion of conductor 240a is sometimes formed by embedding it in conductor 242a. Similarly, the lower portion of conductor 240b is sometimes formed by embedding it in conductor 242b. Similarly, the lower portion of conductor 240c is sometimes formed by embedding it in conductor 218.

[0157] As insulators 241a, 241b, and 241c, barrier insulators suitable for insulators 275 and the like can be used. For example, silicon nitride can be used as insulators 241a, 241b, and 241c. Insulators 241a, 241b, and 241c are arranged in contact with insulators 285, 283, 282, 275, 271a, 271b, 222, and 221. This prevents impurities such as water and hydrogen contained in insulators 280 from being mixed into oxide 230 through conductors 240a, 240b, and 240c. In particular, silicon nitride has high hydrogen barrier properties, so it is preferred. Furthermore, it prevents oxygen contained in insulator 280 from being absorbed by conductors 240a, 240b, and 240c.

[0158] Furthermore, insulators 241a and 241b may also have a laminated structure. In this case, an oxygen-barrier insulator and a hydrogen-barrier insulator are preferably used in combination as the first insulator that contacts the sidewall of the opening of the insulator 280, etc., and the second insulator inside it.

[0159] <Example of Variation 1> exist Figure 1B In some cases, the insulator 250 contacts the side of the insulator 280 in the opening provided in the insulator 280; however, the present invention is not limited to this structure. For example, an insulator may also be provided between the insulator 250 and the insulator 280 in this opening.

[0160] Reference Figures 6A to 7B This section explains variations of the semiconductor device described in "Structural Examples of Semiconductor Devices". Figures 6A to 6D These are plan and cross-sectional views of a semiconductor device including transistor 200, respectively corresponding to... Figures 6A to 6D The plan view and cross-sectional view are shown. Additionally, Figure 7A and Figure 7B This is a magnified cross-sectional view of the channel length of transistor 200, corresponding to... Figure 3A Part of and Figure 3B The enlarged cross-section shown.

[0161] Figures 6A to 6D The transistor 200 shown is Figures 1A to 1D The transistor 200 shown is a modified example. Specifically, Figures 6A to 6D The transistor 200 shown includes an insulator 255, which is in contrast to Figures 1A to 1D The transistor 200 shown is mainly different. The following mainly describes the parts that differ from the description in the above <Example of Semiconductor Device Structure>, while repeating parts are referred to in the above description, and sometimes omitted.

[0162] Furthermore, in Figure 6, both conductors 242a and 242b have a two-layer structure. Conductor 242a has a stacked structure of conductor 242a1 and conductor 242a2 on conductor 242a1. Conductor 242b has a stacked structure of conductor 242b1 and conductor 242b2 on conductor 242b1. Conductors 242a1 and 242b1 correspond to the lower layer of conductors 242a and 242b, and conductors 242a2 and 242b2 correspond to the upper layer of conductors 242a and 242b.

[0163] like Figure 6B and Figure 6CAs shown, the insulator 255 is disposed inside the opening formed in the insulator 280, and contacts the side surface of the insulator 280, the side surface of the conductor 242a2, the side surface of the conductor 24262, the top surface of the conductor 242a1, the top surface of the conductor 242b1, and the top surface of the insulator 222 in the opening. In other words, the insulator 255 can be described as being formed as a sidewall in contact with the sidewall of the opening formed in the insulator 280. Here, the sidewall of the opening corresponds, for example, to the side surface of the insulator 280, etc., in the opening.

[0164] In addition, insulator 250 is in side contact with insulator 255. The insulator 255 preferably has oxygen-barrier properties. When the insulator 255 has oxygen-barrier properties, the oxidation of the sides of the conductors 242a and 242b, resulting in the formation of an oxide film on those sides, can be suppressed. Therefore, the decrease in the on-state current or the decrease in the field-effect mobility of the transistor 200 can be suppressed.

[0166] The opening in the insulator 280 overlaps with the area between conductors 242a2 and 242b2. In a top view, the side of the insulator 280 in the opening is aligned with the side of each conductor 242a2 and conductor 242b2. Furthermore, portions of conductors 242a1 and 242b1 are formed to protrude inwards from the opening. In other words, in conductor 242a1, the portion on its top surface where the insulator 255 is formed protrudes towards conductor 260 from conductor 242a2. Similarly, in conductor 242b1, the portion on its top surface where the insulator 255 is formed protrudes towards conductor 260 from conductor 242b2.

[0167] Here, a portion of the top surface of conductor 242a1 contacts conductor 242a2, and a portion of the top surface of conductor 242b1 contacts conductor 242b2. Therefore, the insulator 255 contacts the remaining portion of the top surface of conductor 242a1, the remaining portion of the top surface of conductor 242b1, the side surface of conductor 242a2, and the side surface of conductor 242b2 on the inner side of the opening. Additionally, the insulator 250 contacts the top surface of oxide 230, the side surface of conductor 242a1, the side surface of conductor 242b1, and the side surface of insulator 255.

[0168] The insulator 255 is formed into a sidewall shape by anisotropic etching to contact the sidewall of the opening provided in the insulator 280. The insulator 255 is formed to contact the sidewalls of the conductor 242a2 and the sidewalls of the conductor 242b2, and has the function of protecting the conductor 242a2 and the conductor 242b2.

[0169] Furthermore, when divided into conductor 242a1 and conductor 242b1, insulator 255 is used as a mask. Therefore, as Figure 7A As shown, when the transistor 200 is viewed in cross section, the side end of the insulator 255 is aligned with the side end of the conductor 242a1 and the side end of the conductor 242b1. After separating the conductors 242a1 and 242b1 and before depositing the insulator 250, it is preferable to perform heat treatment in an oxygen-containing atmosphere. At this time, since the insulator 255 is formed in contact with the sides of the conductors 242a2 and 242b2, excessive oxidation of the conductors 242a2 and 242b2 can be prevented. When microwave treatment is performed after separating the conductors 242a1 and 242b1, the formation of an oxide film on the sides of the conductors 242a1 and 242b2 can also be suppressed.

[0171] The insulators 255 and 250 and the conductor 260 are arranged to reflect the shape of the opening in the insulator 280. Therefore, the insulator 255 is arranged to cover the sidewall of the opening, the insulator 250 is arranged to cover the bottom of the opening and the insulator 255, and the conductor 260 is arranged to be embedded in the recess of the insulator 250.

[0172] Note that, similar to the above <Structure Example of a Semiconductor Device>, the insulator 250 can also have a stacked structure. For example, as shown... Figure 7A As shown, insulator 250 can also have a three-layer structure consisting of insulator 250a, insulator 250b, and insulator 250c. Furthermore, for example, as... Figure 7B As shown, insulator 250 can also have a four-layer structure consisting of insulator 250a, insulator 250b, insulator 250c and insulator 250d.

[0173] Furthermore, the thickness of the insulator 255 is preferably 0.5 nm or more and 20 nm or less, more preferably 0.5 nm or more and 10 nm or less, and even more preferably 0.5 nm or more and 3 nm or less. When the insulator 255 has the above-mentioned thickness, excessive oxidation of the conductors 242a2 and 242b2 can be suppressed. Note that the insulator 255 only needs to have a region with the above-mentioned thickness in at least a portion of it. In addition, since the insulator 255 is provided in contact with the sidewall of the opening formed in the insulator 280, it is preferable to use a deposition method such as ALD with high coverage. When the thickness of the insulator 255 is too large, the deposition time of the insulator 255 using the ALD method is long, resulting in a decrease in productivity. Therefore, it is preferable to set the thickness of the insulator 255 approximately within the above-mentioned range. Furthermore, the thickness of the insulator 255 is preferably such that it does not excessively block the diffusion of excess oxygen from the insulator 280 to the insulator 250b and from the insulator 250b to the oxide 230.

[0174] like Figure 7A As shown, when viewed in cross-section along the channel length of transistor 200, the distance L2 between conductors 242a1 and 242b1 is smaller than the distance L1 between conductors 242a2 and 242b2. Specifically, the difference between distance L1 and distance L2 is equal to twice the thickness of insulator 255. In other words, distance L1 is equal to distance L2 plus twice the thickness of insulator 255. Here, the thickness of insulator 255 refers to the width of at least a portion of insulator 255 in the A1-A2 direction. By adopting this structure, the distance between the source and drain can be further shortened, and the channel length can be correspondingly reduced. Therefore, the frequency characteristics of transistor 200 can be improved. Thus, by miniaturizing the semiconductor device, a semiconductor device with improved operating speed can be provided.

[0175] Alternatively, the insulator 255 may have a stacked structure with two or more layers. In this case, at least one layer is preferably an inorganic insulator that is not easily oxidized, as described above. For example, the first insulator of the insulator 255 may be an inorganic insulator that is not easily oxidized, and the second insulator on the first insulator of the insulator 255 may be an insulator suitable for the insulator 250b (e.g., silicon oxide). The dielectric constant of the second insulator of the insulator 255 is preferably lower than that of the first insulator of the insulator 255. In this way, by adopting a two-layer structure to increase the thickness of the insulator 255, the distance between the conductor 260 and the conductor 242a or the conductor 242b can be increased, thereby reducing parasitic capacitance.

[0176] <Example 2 of the variation> Figures 8A to 9B Show Figure 2BThe semiconductor device shown has wiring and capacitors formed on its upper and lower layers.

[0177] Reference Figures 8A to 9B This section explains variations of the semiconductor device described in "Structural Examples of Semiconductor Devices". Figures 8A to 9B It is a cross-sectional view of a semiconductor device including transistor 200, and has corresponding Figure 2B Part of the semiconductor device shown. Figure 8A The cross-section corresponding to the channel length direction of transistor 200. Figure 8B The cross-section corresponding to the channel width direction of transistor 200. Figure 9A yes Figure 8A An enlarged view of capacitor 400 is shown. Figure 9B yes Figure 8A An enlarged view of the conductor 462 shown.

[0178] Figure 8A and Figure 8B The transistor 200 shown and the structure around it correspond to Figure 1A Transistor 200 is shown in Figure ID. The following mainly describes the parts that differ from the description in the above <Example of Semiconductor Device Structure>, while repeating parts are referred to in the above description, and sometimes the description is omitted.

[0179] like Figure 8A As shown, an insulator 213 serving as an interlayer film is formed beneath the insulator 212 under transistor 200. The insulator 213 is formed to cover the conductor 219 used for wiring. The insulator 213 can be formed using the same material as the insulator 280. A conductor 217 is formed inside an opening formed in the insulators 214, 212, and 213. This opening reaches the top surface of the conductor 219, and the conductor 217 contacts the top surface of the conductor 219. Therefore, the conductor 219 and the conductor 218 are electrically connected through the conductor 217, which serves as a through-hole. The conductor 217 can be formed using the same material as conductors 240a to 240c.

[0180] In addition, such as Figure 8A and Figure 8B As shown, insulators 450, 488, and 487, serving as interlayer films, are formed on insulator 285 on transistor 200. Insulator 450 can be formed using the same material as insulator 280. Insulator 487 is formed to cover conductors 412, 413, and 414 used for wiring, as well as capacitor 400. Capacitor 400 includes conductor 410, insulator 430 covering conductor 410, and conductor 420 on insulator 430.

[0181] Here, conductor 410 is formed in contact with the top surface of conductor 240a, conductor 413 is formed in contact with the top surface of conductor 240b, conductor 412 is formed in contact with the top surface of conductor 240c, and conductor 414 is formed in contact with the top surface of conductor 240d. That is, conductor 410 is electrically connected to conductor 242a, conductor 413 is electrically connected to conductor 242b, conductor 412 is electrically connected to conductor 218, and conductor 414 is electrically connected to conductor 260. Furthermore, conductor 240d is formed inside an opening formed in insulators 285, 283, and 282. This opening reaches the top surface of conductor 260, and conductor 240d is in contact with the top surface of conductor 260. Additionally, insulator 241d is formed to cover the side surface of this opening. Conductor 240d and conductors 240a to 240c can be formed in the same process and use the same materials. Insulator 241d and insulators 241a to 241c can be formed in the same process and use the same materials.

[0182] An insulator 470, serving as an interlayer film, is formed on insulator 450. Insulator 470 is formed to cover conductor 462, which serves as a wiring element. Insulator 470 can be formed using the same material as insulator 280. Conductor 462 is formed to contact the top surfaces of conductors 440a and 440b. Conductors 440a and 440b are formed inside openings formed in insulators 450, 488, and 487. The opening where conductor 440a is formed reaches the top surface of conductor 420, and conductor 440a contacts the top surface of conductor 420. Additionally, an insulator 441a is formed to cover the side surface of the opening where conductor 440a is formed. The opening where conductor 440b is formed reaches the top surface of conductor 412, and conductor 440b contacts the top surface of conductor 412. Furthermore, an insulator 441b is formed to cover the side of the opening where the conductor 440b is formed. Conductors 440a and 440b can be formed in the same process as conductors 240a to 240d using the same materials. Insulators 441a and 441b can be formed in the same process as insulators 241a to 241d using the same materials. Furthermore, since conductors 440a and 440b are located in the layer above the insulator 283, insulators 441a and 441b may not be necessary if impurities such as hydrogen diffusing into the layers of conductors 240a to 240d can be sufficiently reduced.

[0183] The capacitor 400 includes a conductor 410 serving as a first electrode, a conductor 420 serving as a second electrode, and an insulator 430 serving as a dielectric. In other words, the capacitor 400 constitutes a MIM (Metal-Insulator-Metal) capacitor. Conductors 410 and 420 can be made of conductive materials suitable for conductor 260. For example, tungsten can be used for conductors 410 and 420. Here, by using a structure where conductor 420 covers conductor 410, the side of conductor 410 can be used as capacitor 400. This increases the electrostatic capacitance of capacitor 400. Furthermore, conductors 412, 413, and 414 can be formed simultaneously with conductor 410.

[0185] In Figure 8, conductors 410, 412, 413, 414, and 420 have a single-layer structure, but are not limited to this structure and may also have a stacked structure of two or more layers. For example, a stacked structure of a barrier conductor and a highly conductive conductor can be used. For example, a stacked structure of titanium nitride and tungsten on titanium nitride can be used.

[0186] The insulator 430 included in the capacitor 400 is preferably made of a material with a high relative permittivity (high-k). Examples of high-k materials include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxynitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxynitrides containing silicon and hafnium, or nitrides containing silicon and hafnium. By using such a high-k material, the thickness of the insulator 430 can be set to a level that suppresses leakage current, and the electrostatic capacitance of the capacitor 400 can be sufficiently ensured. Furthermore, since the insulator 430 is formed to cover the conductor 410, it is preferable to deposit it using a deposition method with high coverage, such as ALD or CVD.

[0187] Furthermore, the insulator 430 may also have a laminated structure. Preferably, a laminated structure is used, consisting of a material with a high relative permittivity (high-k) and a material with a dielectric strength greater than that of the material with the high relative permittivity (high-k). Materials with high dielectric strength (materials with low relative permittivity) include silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, fluorine-added silicon oxide, carbon-added silicon oxide, and silicon oxide with both carbon and nitrogen added. Figure 9A As shown, when the insulator 430 has a stacked structure of insulator 430a and insulator 430b on insulator 430a, insulator 430a can be made of alumina, a material with a high relative permittivity (high-k), and insulator 430b can be made of silicon oxide, which has a high dielectric strength. Furthermore, for example, as insulator 430, an insulator consisting of zirconium oxide, aluminum oxide, and zirconium oxide stacked sequentially can be used. Alternatively, for example, an insulator stacked sequentially in the order of zirconium oxide, aluminum oxide, zirconium oxide, and aluminum oxide can be used. Furthermore, for example, an insulator stacked sequentially in the order of hafnium zirconium oxide, aluminum oxide, hafnium zirconium oxide, and aluminum oxide can be used. By using an insulator with high dielectric strength, such as aluminum oxide, the dielectric strength is increased, thereby suppressing electrostatic discharge damage to the capacitor 400.

[0189] Alternatively, insulator 430 can also be made of a material that may possess ferroelectric properties. Examples of materials that may possess ferroelectric properties include hafnium oxide, zirconium oxide, and HfZrO. X (X is a real number greater than 0) and other metal oxides. Furthermore, materials that may exhibit ferroelectric properties include hafnium oxide with the addition of element J1 (here, element J1 is selected from one or more of zirconium, silicon, aluminum, gadolinium, yttrium, lanthanum, strontium, etc.). Here, the ratio of the number of hafnium atoms to the number of element J1 atoms can be appropriately set; for example, the ratio can be set to 1:1 or close to 1. Furthermore, materials that may exhibit ferroelectric properties include zirconium oxide with the addition of element J2 (here, element J2 is selected from one or more of hafnium, silicon, aluminum, gadolinium, yttrium, lanthanum, strontium, etc.). Furthermore, the ratio of the number of zirconium atoms to the number of element J2 atoms can be appropriately set; for example, the ratio can be set to 1:1 or close to 1. Additionally, lead titanate (PbTiO2) can also be used as a material that may exhibit ferroelectric properties. X Piezoelectric ceramics with perovskite structure include barium strontium titanate (BST), strontium titanate, lead zirconate titanate (PZT), strontium bismuth tantalate (SBT), bismuth ferrite (BFO), and barium titanate.

[0190] Furthermore, metal nitrides containing elements M1, M2, and nitrogen can be cited as materials that may exhibit ferroelectric properties. Here, element M1 is selected from one or more of aluminum, gallium, indium, etc. Furthermore, element M2 is selected from one or more of boron, scandium, yttrium, lanthanum, cerium, neodymium, europium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, etc. Furthermore, the ratio of the number of atoms of element M1 to the number of atoms of element M2 can be appropriately set. Additionally, metal oxides containing elements M1 and nitrogen sometimes exhibit ferroelectric properties even without element M2. Furthermore, materials that may exhibit ferroelectric properties include those to which element M3 is added. Note that element M3 is selected from one or more of magnesium, calcium, strontium, zinc, cadmium, etc. Here, the ratio of the number of atoms of element M1, the number of atoms of element M2, and the number of atoms of element M3 can be appropriately set.

[0191] In addition, perovskite-type oxynitrides such as SrTaO2N and BaTaO2N, and κ-type alumina such as GaFeO3 can be cited as materials that may have ferroelectric properties.

[0192] Note that while examples of metal oxides and metal nitrides are shown in the above description, the invention is not limited to these. For example, metal oxynitrides with nitrogen added to the aforementioned metal oxides or metal oxynitrides with oxygen added to the aforementioned metal nitrides may also be used.

[0193] Furthermore, as materials that may exhibit ferroelectricity, for example, a mixture or compound composed of multiple materials selected from the above-mentioned materials can be used. Alternatively, the insulator 430 may have a layered structure composed of multiple materials selected from the above-mentioned materials. Note that the crystal structure (characteristics) of the materials listed above may vary not only depending on the deposition conditions but also depending on various processes, etc. Therefore, in this specification, materials exhibiting ferroelectricity are referred not only to ferroelectric materials but also to materials that may exhibit ferroelectricity.

[0194] Note that in the semiconductor device shown in FIG8, the capacitor 400 is planar in shape, but the semiconductor device shown in this embodiment is not limited to this. For example, the capacitor 400 may also be cylindrical in shape.

[0195] An insulator 487 is provided to cover the capacitor 400, and an insulator 488 is provided to cover the insulator 487. As the insulator 487, an insulator with the function of trapping or fixing hydrogen is preferably used. For example, aluminum oxide can be used as the insulator 487. As the insulator 488, an insulator with the function of inhibiting hydrogen diffusion is preferably used. For example, silicon nitride, which has higher hydrogen barrier properties, can be used as the insulator 488.

[0196] Furthermore, such as Figure 9A As shown, the insulator 487 preferably has a stacked structure of insulator 487a and insulator 487b on insulator 487a. Preferably, insulator 487a is deposited using an ALD method, and insulator 487b is deposited using a sputtering method. For example, alumina deposited using a thermal ALD method can be used as insulator 487a, and alumina deposited using a sputtering method can be used as insulator 487b. By depositing insulator 487b using a sputtering method while insulator 487a is already deposited, capacitor 400 and the like can be protected from ion collisions generated by the sputtering deposition of insulator 487b. Furthermore, by using an ALD method with high step coverage to deposit insulator 487a, insulator 487a can be deposited without forming pinholes or breaks at the steps of capacitor 400 and the like.

[0197] Furthermore, such as Figure 9AAs shown, the insulator 488 preferably has a stacked structure of insulator 488a and insulator 488b on insulator 488a. Preferably, insulator 488a is deposited using a sputtering method, and insulator 488b is deposited using an ALD method. For example, silicon oxide deposited using a sputtering method can be used as insulator 488a, and silicon oxide deposited using a PEALD method can be used as insulator 488b. Even if pinholes or breaks are formed in the insulator 488a near a step in the capacitor 400, hydrogen barrier properties can be maintained when the insulator 488a is covered from above by the insulator 488b deposited using an ALD method with high step coverage.

[0198] Thus, by providing insulator 488 on capacitor 400, the diffusion of hydrogen from the upper layer of capacitor 400 can be suppressed. Furthermore, by providing insulator 487 below insulator 488, hydrogen contained in capacitor 400, insulator 285, etc., can be captured or fixed by insulator 487.

[0199] exist Figure 8A In this structure, conductor 462 has a single-layer structure, but is not limited to this structure and can also have a stacked structure of two or more layers. For example, a structure can be made by sandwiching a highly conductive metal material between a highly heat-resistant metal material. As a highly conductive metal material, aluminum, copper, etc. can be used. In addition, as a highly heat-resistant metal material, molybdenum, titanium, tungsten, and their nitrides can be used.

[0200] For example, such as Figure 9B As shown, conductor 462 can also have a five-layer structure in which conductors 462a, 462b, 462c, 462d, and 462e are stacked sequentially. For example, aluminum with high conductivity can be used as conductor 462c, titanium with high heat resistance can be used as conductors 462a and 462d, and titanium nitride with high heat resistance can be used as conductors 462b and 462e. By adopting this structure, even when using aluminum with low heat resistance, defects such as hillocks, whiskers, or migration can be suppressed. Therefore, conductor 462 can be used as a highly conductive wiring. Furthermore, Figure 8A The conductor 219 shown can also have the same structure as the conductor 462.

[0201] Note that the wiring and circuit element connection structure of the semiconductor device shown in this embodiment are not limited to... Figure 8A The structure shown. For example, in Figure 8AIn this configuration, conductors 219, 218, 412, and 462, used for wiring in each layer, are connected via conductors 217, 240c, and 440b, which serve as through-holes. However, this configuration is not limited to this; any circuit can be formed by selecting wiring and through-holes from the above structure. Furthermore, in... Figure 8A In this embodiment, a wiring layer is provided under the transistor 200 and on the capacitor 400. However, the present invention is not limited to this, and two or more wiring layers can be provided under the transistor 200 and on the capacitor 400. As described above, in this embodiment, transistors, circuit elements, and wiring in each layer can be connected to each other through vias to form a circuit of arbitrary structure. For example, pixel circuits of a display device can be formed.

[0202] Materials Constituting Semiconductor Devices The following describes the materials that can be used to construct semiconductor devices. Note that the layers constituting a semiconductor device can have either a single-layer structure or a multilayer structure.

[0203] Substrate Substrates for forming transistors can be, for example, insulating substrates, semiconductor substrates, or conductive substrates. Examples of insulating substrates include glass substrates, quartz substrates, sapphire substrates, stabilized zirconia substrates (yttrium-stabilized zirconia substrates, etc.), and resin substrates. Examples of semiconductor substrates include semiconductor substrates made of silicon or germanium, and compound semiconductor substrates made of silicon carbide, silicon-germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide. Furthermore, semiconductor substrates having insulating regions within the aforementioned semiconductor substrates can also be used, such as SOI (Silicon On Insulator) substrates. Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, and conductive resin substrates. Additionally, examples of substrates include substrates containing metal nitrides, substrates containing metal oxides, insulating substrates with conductors or semiconductors, semiconductor substrates with conductors or insulators, and conductive substrates with semiconductors or insulators. Alternatively, substrates on which one or more elements are disposed can also be used. Examples of components disposed on a substrate include capacitors, resistors, switching elements, light-emitting elements, and storage elements.

[0204] Insulators Examples of insulating materials include oxides, nitrides, oxynitrides, nitrogen oxides, metal oxides, metal oxynitrides, and metal nitrogen oxides.

[0205] For example, when miniaturizing and highly integrating transistors, problems such as leakage current sometimes occur due to the thinning of the gate insulator. By using a high-k material as the insulator used as the gate insulator, low voltage can be achieved during transistor operation while maintaining the physical thickness. On the other hand, by using a material with a relatively low permittivity as the insulator used as the interlayer film, parasitic capacitance generated between wirings can be reduced. Therefore, it is preferable to select materials based on the function of the insulator.

[0206] Examples of insulators with relatively high permittivity include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxynitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxynitrides containing silicon and hafnium, or nitrides containing silicon and hafnium.

[0207] Examples of insulators with relatively low permittivity include silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, porous silicon oxide, and resins.

[0208] Furthermore, by surrounding a transistor using a metal oxide with an insulator that suppresses the permeation of impurities such as hydrogen and oxygen, the electrical characteristics of the transistor can be stabilized. Examples of insulators that suppress the permeation of impurities such as hydrogen and oxygen include single layers or stacks of one or more of boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, and tantalum. Specifically, examples of insulators that suppress the permeation of impurities such as hydrogen and oxygen include metal oxides such as aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, and tantalum oxide, as well as metal nitrides such as aluminum nitride, silicon oxynitride, and silicon nitride.

[0209] Furthermore, the insulator used as the gate insulator is preferably an insulator having a region containing oxygen that has been removed by heating. For example, when a structure of silicon oxide or silicon oxynitride contact oxide 230 with a region containing oxygen that has been removed by heating is used, the oxygen vacancies contained in oxide 230 can be filled.

[0210] Conductors As a conductor, it is preferable to use a metallic element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, cobalt, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum, an alloy containing the above-mentioned metallic elements, or an alloy combining the above-mentioned metallic elements. Examples of conductors include tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel. Furthermore, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferred because they are conductive materials that are not easily oxidized or maintain conductivity even after absorbing oxygen. Alternatively, semiconductors with high conductivity, such as polycrystalline silicon containing impurity elements like phosphorus, or silicides such as nickel silicides can be used.

[0211] When using a conductor with a multilayer structure, for example, a multilayer structure combining a material containing the aforementioned metal element and a conductive material containing oxygen, a multilayer structure combining a material containing the aforementioned metal element and a conductive material containing nitrogen, or a multilayer structure combining a material containing the aforementioned metal element, a conductive material containing oxygen, and a conductive material containing nitrogen may also be used.

[0212] Furthermore, when using oxides in the channel formation region of a transistor, a stacked structure combining a material containing the aforementioned metallic elements and an oxygen-containing conductive material is preferably used as the conductor serving as the gate electrode. In this case, it is preferable to provide the oxygen-containing conductive material on one side of the channel formation region. By providing the oxygen-containing conductive material on one side of the channel formation region, oxygen detached from this conductive material can be easily supplied to the channel formation region.

[0213] In particular, as the conductor used as the gate electrode, a conductive material containing a metal element and oxygen contained in the metal oxide forming the channel is preferably used. Alternatively, a conductive material containing the aforementioned metal element and nitrogen can also be used. For example, nitrogen-containing conductive materials such as titanium nitride and tantalum nitride can be used. Furthermore, one or more of the following can be used: indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, and indium tin oxide with added silicon. Additionally, indium gallium zinc oxide containing nitrogen can also be used. By using the above materials, hydrogen contained in the metal oxide forming the channel can sometimes be trapped. Alternatively, hydrogen mixed in from external insulators or the like can sometimes be trapped.

[0214] Metal Oxides As oxide 230, a metal oxide (oxide semiconductor) used as a semiconductor is preferably used. Hereinafter, a metal oxide that can be used as oxide 230 according to one aspect of the present invention will be described.

[0215] The metal oxide preferably contains at least indium or zinc. Indium and zinc are particularly preferred. In addition, it preferably contains aluminum, gallium, yttrium, tin, antimony, etc. Furthermore, it may contain one or more elements selected from boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt.

[0216] Consider the case where the metal oxide is an In-M-Zn oxide containing indium, element M, and zinc. Note that element M can be aluminum, gallium, yttrium, tin, or antimony. Other elements that can be used with element M include boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, and cobalt. Note that multiple of the above elements can sometimes be combined as element M. In particular, element M is preferably selected from one or more of gallium, aluminum, yttrium, and tin.

[0217] Furthermore, in this specification and other materials, nitrogen-containing metal oxides are sometimes referred to as metal oxides. Additionally, nitrogen-containing metal oxides may also be referred to as metal oxynitrides.

[0218] The following is an example of an In-Ga-Zn oxide as a metal oxide.

[0219] Examples of crystalline structures for oxide semiconductors include amorphous (including completely amorphous), CAAC (c-axis-aligned crystalline), nc (nanocrystalline), CAC (cloud-aligned composite), single crystal, and polycrystalline.

[0220] Furthermore, when considering the structure of oxide semiconductors, their classification sometimes differs from that described above. For example, oxide semiconductors can be classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include, for instance, CAAC-OS and nc-OS, as mentioned above. In addition, non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, a-like OS (amorphous-like oxide semiconductor), and amorphous oxide semiconductors, among others.

[0221] Here, we will explain the details of CAAC-OS, nc-OS, and a-like OS.

[0222] [CAAC-OS] CAAC-OS is an oxide semiconductor comprising multiple crystalline regions whose c-axis is oriented in a specific direction. This specific direction refers to the thickness direction of the CAAC-OS film, the normal direction of the formed surface of the CAAC-OS film, or the normal direction of the surface of the CAAC-OS film. Furthermore, a crystalline region is a region exhibiting a periodic atomic arrangement. Note that when atomic arrangement is considered as lattice arrangement, a crystalline region is also a region with a consistent lattice arrangement. Moreover, CAAC-OS has a region where multiple crystalline regions are connected in the ab-plane direction, and sometimes this region exhibits distortion. Distortion refers to the portion of the lattice arrangement direction that changes between regions with consistent lattice arrangement and other regions with consistent lattice arrangement in the region where multiple crystalline regions are connected. In other words, CAAC-OS refers to an oxide semiconductor with c-axis orientation but no obvious orientation in the ab-plane direction.

[0223] Furthermore, each of the aforementioned crystalline regions consists of one or more microcrystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region consists of a single microcrystal, the maximum diameter of that region is less than 10 nm. Conversely, when a crystalline region consists of multiple microcrystals, the maximum diameter of that region can sometimes be around tens of nm.

[0224] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, it can be said that in CAAC-OS, the reduction in electron mobility due to grain boundaries is less likely to occur. Furthermore, the crystallinity of oxide semiconductors can sometimes decrease due to the incorporation of impurities or the formation of defects; therefore, CAAC-OS can be considered an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Consequently, oxide semiconductors containing CAAC-OS exhibit stable physical properties. Thus, oxide semiconductors containing CAAC-OS possess high heat resistance and high reliability. Moreover, CAAC-OS is also stable against high temperatures (so-called thermal accumulation) during manufacturing processes. Therefore, by using CAAC-OS in OS transistors, the degrees of freedom in manufacturing processes can be increased.

[0225] [nc-OS] In nc-OS, the atomic arrangement in tiny regions (e.g., regions larger than 1 nm and smaller than 10 nm, particularly regions larger than 1 nm and smaller than 3 nm) exhibits periodicity. In other words, nc-OS possesses tiny crystallinity. Furthermore, for example, these tiny crystallinity sizes are between 1 nm and 10 nm, particularly between 1 nm and 3 nm; these tiny crystallinity sizes are referred to as nanocrystals. Moreover, no regularity in crystallization orientation is observed between different nanocrystals in nc-OS. Therefore, no orientation is observed in the overall film. Thus, sometimes nc-OS is indistinguishable from a-like OS or amorphous oxide semiconductors in certain analytical methods.

[0226] [a-like OS] a-like OS is an oxide semiconductor with a structure intermediate between nc-OS and amorphous oxide semiconductors. a-like OS contains voids or low-density regions. That is, a-like OS has lower crystallinity than nc-OS and CAAC-OS. Furthermore, the hydrogen concentration in a-like OS films is higher than that in nc-OS and CAAC-OS films.

[0227] Next, the details of CAC-OS will be explained. Furthermore, CAC-OS is related to material composition.

[0228] [CAC-OS] CAC-OS, for example, refers to a composition in which elements are unevenly distributed within a metal oxide, wherein the size of the material containing the unevenly distributed elements is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or approximately. Note that below, the state in which one or more metal elements are unevenly distributed within a metal oxide and the regions containing those metal elements are mixed is also referred to as mosaic or patch-like, where the size of the region is 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 3 nm or approximately.

[0229] Furthermore, CAC-OS refers to a structure in which the material is divided into a first region and a second region, forming a mosaic-like structure, with the first region distributed throughout the film (hereinafter also referred to as cloud-like). In other words, CAC-OS refers to a composite metal oxide having a structure that combines the first and second regions.

[0230] Furthermore, CAC-OS in In-Ga-Zn oxides refers to a structure in which regions dominated by In (first region) and regions dominated by Ga (second region) exist irregularly in a mosaic pattern within a material composition containing In, Ga, Zn, and O. Therefore, it can be inferred that CAC-OS has a structure with uneven distribution of metallic elements.

[0231] CAC-OS can be formed, for example, by sputtering without heating the substrate. When forming CAC-OS by sputtering, one or more gases selected from inert gases (typically argon), oxygen gases, and nitrogen gases can be used as the deposition gas. Furthermore, the lower the oxygen gas flow rate in the total flow rate of the deposition gases during deposition, the better. For example, the oxygen gas flow rate in the total flow rate of the deposition gases during deposition is set to 0% or more and less than 30%, preferably 0% or more and less than 10%.

[0232] Here, the first region has higher conductivity than the second region. That is, when charge carriers flow through the first region, it exhibits the conductivity of a metal oxide. Therefore, when the first region is distributed in a cloud-like manner within the metal oxide, a high field-effect mobility (μ) can be achieved.

[0233] On the other hand, the second region has higher insulation properties than the first region. That is, when the second region is distributed in a metal oxide, leakage current can be suppressed.

[0234] Therefore, when CAC-OS is used in a transistor, the complementary effect of conductivity arising from the first region and insulation arising from the second region enables CAC-OS to possess switching functionality (the function of controlling on / off). In other words, a portion of the CAC-OS material exhibits conductivity while another portion exhibits insulation, resulting in a semiconductor function within the material as a whole. By separating the conductive and insulating functions, each function can be maximized. Therefore, by using CAC-OS in a transistor, a large on-state current (If) can be achieved. on It has high field-effect mobility (μ) and good switching performance.

[0235] Furthermore, transistors using CAC-OS exhibit high reliability. Therefore, CAC-OS is best suited for various semiconductor devices, such as display devices.

[0236] Oxide semiconductors possess various structures and properties. In one embodiment of the present invention, the oxide semiconductor may also include two or more of the following: amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, CAC-OS, nc-OS, and CAAC-OS. Other Semiconductor Materials As the semiconductor layer of a transistor, a semiconductor material with a band gap (a semiconductor material that is not a zero-bandgap semiconductor) can also be used. For example, a single-element semiconductor such as silicon or a compound semiconductor such as gallium arsenide can also be used.

[0238] Furthermore, transition metal chalcogenides, which are typically used as semiconductors, are preferably used as the semiconductor layer of a transistor. Examples of transition metal chalcogenides suitable for use as semiconductor layers in transistors include molybdenum sulfide (typically MoS2), molybdenum selenide (typically MoSe2), molybdenum telluride (typically MoTe2), tungsten sulfide (typically WS2), tungsten selenide (typically WSe2), tungsten telluride (typically WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically HfSe2), zirconium sulfide (typically ZrS2), and zirconium selenide (typically ZrSe2). By using the aforementioned transition metal chalcogenides as the semiconductor layer of a transistor, a semiconductor device with a large on-state current can be provided.

[0239] <Examples of Semiconductor Device Manufacturing Methods> Reference Figures 10A to 15C An example of a method for manufacturing a semiconductor device according to one aspect of the present invention will be described. Here, the manufacturing process will be described. Figure 2B The case of the semiconductor device shown will be used as an example for explanation.

[0240] Figures 10A to 11C , Figures 13A to 15C It corresponds to Figure 2B The cross-sectional view is also a cross-sectional view along the channel length of transistor 200. Additionally, Figures 12A1 to 12D1 It corresponds to Figure 1B A partial cross-sectional view, also a cross-sectional view along the channel length of transistor 200. Additionally, Figures 12A2 to 12D2 It corresponds to Figure 1C A partial cross-sectional view, which is also a cross-sectional view of the channel width direction of transistor 200.

[0241] The insulating materials used to form insulators, the conductive materials used to form conductors, or the semiconductor materials used to form semiconductors can be deposited using methods such as sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), and ALD. Examples of sputtering methods include RF sputtering, which uses a high-frequency power supply, DC sputtering, which uses a DC power supply, and pulsed DC sputtering, which changes the voltage applied to the electrodes in a pulsed manner. RF sputtering is mainly used when depositing insulating films, while DC sputtering is mainly used when depositing conductive metal films. Furthermore, pulsed DC sputtering is mainly used when depositing compounds such as oxides, nitrides, and carbides using reactive sputtering.

[0243] Note that CVD methods can be categorized into plasma-enhanced CVD (PECVD), thermal CVD (TCVD), and photo CVD. Furthermore, they can be classified based on the source gas used, such as metal CVD (MCVD) and metal-organic CVD (MOCVD).

[0244] By utilizing plasma CVD, high-quality films can be obtained at relatively low temperatures. Furthermore, because it does not use plasma, thermal CVD is a deposition method that reduces plasma damage to the workpiece. For example, wiring, electrodes, and components (transistors, capacitors, etc.) in semiconductor devices sometimes accumulate charge due to receiving charge from plasma. This accumulated charge can sometimes damage these wiring, electrodes, and components. On the other hand, thermal CVD, which does not use plasma, avoids this plasma damage, thus improving the yield of semiconductor devices. Moreover, since thermal CVD does not generate plasma damage during deposition, films with fewer defects can be obtained.

[0245] As an ALD method, one can use thermal ALD, which uses only thermal energy to react the precursors and reactants, or PEALD, which uses reactants excited by plasma.

[0246] CVD and ALD methods differ from sputtering methods that deposit particles released from a target or similar material. Therefore, CVD and ALD are deposition methods that are less affected by the shape of the workpiece and offer high step coverage. In particular, ALD exhibits high step coverage and thickness uniformity, making it suitable for covering surfaces with high aspect ratios and openings. However, ALD has a relatively slow deposition rate, so it is sometimes preferred to combine it with other deposition methods, such as CVD, which has a faster deposition rate.

[0247] Furthermore, when using CVD, films of arbitrary composition can be deposited by adjusting the source gas flow rate ratio. For example, when using CVD, films with continuously varying compositions can be deposited by changing the source gas flow rate ratio simultaneously with deposition. When deposition is performed while changing the source gas flow rate ratio, the deposition time can be shortened compared to deposition using multiple deposition chambers because the time required for transfer or pressure adjustment is eliminated. Therefore, this can sometimes improve the productivity of semiconductor devices.

[0248] When using the ALD method, membranes of arbitrary composition can be deposited by simultaneously introducing multiple different precursors. Alternatively, by controlling the number of cycles for each precursor while introducing multiple different precursors, membranes of arbitrary composition can be deposited.

[0249] First, a substrate (not shown) is prepared, an insulator 212 is deposited on the substrate, and an insulator 214 (see reference) is deposited on the insulator 212. Figure 10A Insulators 212 and 214 can use the aforementioned insulating materials. For example, insulators 212 and 214 can be deposited using sputtering, CVD, MBE, PLD, or ALD methods. Since sputtering does not require the use of hydrogen-containing molecules as the deposition gas, the hydrogen concentration in insulators 212 and 214 can be reduced, which is preferred.

[0250] In this embodiment, silicon nitride is deposited as insulator 212 using sputtering, and aluminum oxide is deposited as insulator 214 using sputtering. Thus, by using silicon nitride, which has the function of suppressing hydrogen diffusion, as insulator 212, hydrogen diffusion from the lower layer of transistor 200 can be suppressed. Furthermore, by using aluminum oxide, which has the function of trapping or fixing hydrogen, as insulator 214, hydrogen contained in insulator 216 and the like can be trapped or fixed by insulator 214. This reduces the hydrogen concentration in and around oxide 230.

[0251] Furthermore, it is preferable to perform a heat treatment before depositing the insulator 212 to reduce the adsorption of water and hydrogen onto the substrate (including circuit elements and interlayer films formed on the substrate). In this embodiment, the heat treatment temperature is set to 400°C.

[0252] Next, insulator 216A is deposited on insulator 214 (refer to...). Figure 10A The insulator 216A can use the insulating material described above that can be used for insulator 216. Insulator 216A is preferably deposited using a sputtering method. By using a sputtering method, which does not require the use of hydrogen-containing molecules in the deposition gas, the hydrogen concentration in insulator 216A can be reduced. Note that the deposition method for insulator 216A is not limited to sputtering; for example, CVD, MBE, PLD, or ALD methods can also be appropriately used. In this embodiment, silicon oxide is deposited using a sputtering method as insulator 216A.

[0253] Insulators 212, 214, and 216A are preferably deposited continuously without exposure to the atmosphere. For example, a multi-chamber deposition apparatus can be used. This reduces the amount of hydrogen in the film during deposition of insulators 212, 214, and 216A, and also reduces hydrogen ingress into the film between deposition steps.

[0254] Next, openings are formed in insulators 212, 214, and 216A. Wet etching can be used to form the openings, but dry etching is preferred for microfabrication.

[0255] After the opening is formed, a conductive film that will become conductor 217 is deposited, and CMP treatment is performed until the insulator 216A is exposed to remove a portion of the conductive film that will become conductor 217 (see reference). Figure 10A Thus, a conductor 217 embedded in insulators 212 and 214 can be formed. The conductive film that will become the conductor 217 can be deposited using methods such as sputtering, CVD, MBE, PLD, and ALD. For example, a titanium nitride film and a tungsten film can be deposited using CVD. Therefore, the conductor 217 can have a stacked structure of a titanium nitride conductor 217a and a tungsten conductor 217b.

[0256] Next, an insulating film identical to that of insulator 216A is deposited on conductor 217 and insulator 216A to form insulator 216 covering the protrusions of conductor 217 (see reference). Figure 10B ).

[0257] Next, an opening is formed in insulator 216 leading to insulator 214 (see reference). Figure 10C Openings are formed in the regions where conductor 205 will be formed and where conductor 218 will be formed. The upper part of conductor 217 protrudes from the opening into which conductor 218 is embedded. Wet etching can be used when forming the openings, but dry etching is preferred for microfabrication. As insulator 214, it is preferably selected from the same insulator that serves as an etch stop film when etching insulator 216. For example, when silicon oxide or silicon oxynitride is used as insulator 216, silicon nitride, aluminum oxide, or hafnium oxide is preferably used as insulator 214.

[0258] After the opening is formed, a conductive film that will become conductors 205 and 218 is deposited, and CMP treatment is performed until the insulator 216 is exposed to remove a portion of the conductive film that will become conductors 205 and 218 (see reference). Figure 10D Thus, conductors 205 and 218 can be formed embedded in insulator 216. Conductor 218 is formed in such a way as to cover the protrusion of conductor 217.

[0259] Here, the conductive films that will become conductors 205 and 218 can be deposited using the aforementioned conductive materials via sputtering, CVD, MBE, PLD, ALD, or similar methods. For example, tantalum nitride, titanium nitride, and tungsten films can be deposited using CVD. Thus, as... Figure 4A As shown, conductor 205 may have a stacked structure of conductor 205c made of tantalum nitride, conductor 205a made of titanium nitride, and conductor 205b made of tungsten. Furthermore, conductor 218 may have a stacked structure of conductor 218c made of tantalum nitride, conductor 218a made of titanium nitride, and conductor 218b made of tungsten.

[0260] Note that in the above process, the upper part of the conductor 217 is embedded in the conductor 218, but the present invention is not limited thereto. For example, the conductor 217 can be formed such that its top surface is aligned with the top surface of the insulator 214, and... Figure 2A Similarly, the bottom surface of the conductor 218 can be made to have a flat shape.

[0261] Next, insulator 221 is deposited on insulator 216, conductor 205 and conductor 217 (see reference). Figure 10E ).

[0262] The insulator 221 can be any insulator that blocks oxygen, hydrogen, and water as described above. The insulator 221 can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD. In this embodiment, silicon nitride is deposited using the PEALD method as the insulator 221.

[0263] Next, insulator 222 is deposited on insulator 221 (see reference). Figure 10E ).

[0264] The insulator 222 is preferably deposited with an oxide containing one or both of aluminum and hafnium. For example, aluminum oxide, hafnium oxide, and oxides containing aluminum and hafnium (hafnium aluminate) are preferred as the insulator. Alternatively, hafnium zirconium oxide is preferred. The insulator containing one or both of aluminum and hafnium provides a barrier against oxygen, hydrogen, and water. When the insulator 222 provides a barrier against hydrogen and water, the diffusion of hydrogen and water contained in the surrounding structure of the transistor through the insulator 222 to the inside of the transistor can be suppressed, thereby suppressing the generation of oxygen vacancies in the oxide 230.

[0265] The insulator 222 can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD. In this embodiment, hafnium oxide is deposited as the insulator 222 using thermal ALD.

[0266] In this embodiment, silicon nitride is deposited as insulator 221 using the PEALD method, and hafnium oxide is deposited as insulator 222 using the thermal ALD method. Thus, by using silicon nitride, which has the function of suppressing hydrogen diffusion, as insulator 221, hydrogen diffusion from the lower layer of transistor 200 can be suppressed. Furthermore, by using hafnium oxide, which has the function of trapping or fixing hydrogen, as insulator 222, hydrogen in insulator 224 and the like can be trapped or fixed by insulator 222. This reduces the hydrogen concentration in and around oxide 230. Next, an insulating film 224f is deposited on the insulator 222 (refer to...). Figure 10EAs the insulating film 224f, an insulator corresponding to the above-described insulator 224 can be used.

[0268] The insulating film 224f can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD. In this embodiment, silicon oxide is deposited as the insulating film 224f using sputtering. By using a sputtering method that does not require the use of hydrogen-containing molecules as a deposition gas, the hydrogen concentration in the insulating film 224f can be reduced. Since the insulating film 224f comes into contact with the oxide 230 in a subsequent process, it is preferable to reduce the hydrogen concentration as described above.

[0269] Next, an oxide film 230f is deposited on the insulating film 224f (refer to...). Figure 10E As oxide film 230f, the metal oxide material that can be used in oxide 230 described above can be used. In addition, when oxide 230 has a stacked structure of oxide 230a and oxide 230b, a stacked film of metal oxide corresponding to oxide 230a and metal oxide corresponding to oxide 230b can be deposited.

[0270] The oxide film 230f can be deposited, for example, using sputtering, CVD, MBE, PLD, or ALD methods. In this embodiment, the oxide film 230f is deposited using sputtering. By using sputtering, which does not require the use of hydrogen-containing molecules as the deposition gas, the hydrogen concentration in the oxide film 230f can be reduced. Note that when a multilayer film is used as the oxide film 230f, it is preferable to continuously deposit it using sputtering in a manner that does not expose the film to the atmospheric environment. Furthermore, the insulating film 224f and the oxide film 230f are also preferably continuously deposited using sputtering. By depositing the film in a manner that does not expose the film to the atmosphere, the interface or vicinity of the multilayer film can be kept clean.

[0271] For example, when depositing an oxide film 230f using sputtering, oxygen or a mixture of oxygen and rare gases is used as the sputtering gas. By increasing the oxygen content in the sputtering gas, excess oxygen in the deposited oxide film can be increased. Furthermore, when depositing the aforementioned oxide film using sputtering, In-M-Zn oxide targets, etc., can be used.

[0272] In particular, during the deposition of the oxide film 230f, a portion of the oxygen contained in the sputtering gas is sometimes supplied to the insulating film 224f. Therefore, the oxygen content of the sputtering gas is preferably 70% or more, more preferably 80% or more, and even more preferably 100%.

[0273] When forming the oxide film 230f using sputtering, an oxygen-excess oxide semiconductor can be formed by deposition under conditions where the oxygen content in the sputtering gas is more than 30% and less than 100%, preferably more than 70% and less than 100%. Transistors using the oxygen-excess oxide semiconductor in the channel formation region can achieve relatively high reliability. Note that the invention is not limited to this. When forming the oxide film 230f using sputtering, an oxygen-deficient oxide semiconductor is formed when deposition is performed with the oxygen content in the sputtering gas set to more than 1% and less than 30%, preferably more than 5% and less than 20%. Transistors using the oxygen-deficient oxide semiconductor in the channel formation region can have higher field-effect mobility. Furthermore, by performing deposition while heating the substrate, the crystallinity of the oxide film can be improved.

[0274] In this embodiment, oxide film 230a is deposited using an oxide target with an In:Ga:Zn ratio of 1:3:2 or 1:3:4 using sputtering. Alternatively, oxide film 230b is deposited using an oxide target with an In:Ga:Zn ratio of 1:1:1, 1:1:1.2, 4:2:4.1, or 1:1:2 using sputtering. The deposition conditions and atomic ratios of the oxide films can be appropriately selected based on the desired characteristics of oxide 230 (oxide 230a and oxide 230b).

[0275] Next, a heat treatment is preferably performed. The heat treatment is preferably performed within a temperature range in which the oxide film 230f is not polycrystalline. The temperature of the heat treatment is preferably 100°C or higher and 650°C or lower, more preferably 250°C or higher and 600°C or lower, and even more preferably 350°C or higher and 550°C or lower.

[0276] The heat treatment is carried out in a nitrogen or inert gas atmosphere, or in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas. For example, when heat treatment is carried out in a mixed atmosphere of nitrogen and oxygen gas, the oxygen gas ratio is preferably set to about 20%. The heat treatment can also be carried out under reduced pressure. Alternatively, the heat treatment can be carried out in a nitrogen or inert gas atmosphere, and then, in order to replenish the removed oxygen, heat treatment can be carried out in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas.

[0277] Furthermore, the gas used in the above-described heat treatment is preferably of high purity. For example, the water content in the gas used in the above-described heat treatment is preferably 1 ppb or less, more preferably 0.1 ppb or less, and even more preferably 0.05 ppb or less. By using a high-purity gas for heat treatment, the absorption of moisture and the like by the oxide film 230f can be prevented as much as possible. In addition, the high-purity gas can also be used for both the heat treatment before and after this process.

[0278] In this embodiment, as a heat treatment, the process is performed for 1 hour at a nitrogen to oxygen gas flow ratio of 4:1 and a temperature of 450°C. This oxygen-containing heat treatment reduces impurities such as carbon, water, and hydrogen in the oxide film 230f. By reducing impurities in the film, the crystallinity of the oxide film 230f is improved, resulting in a denser structure. Therefore, the crystalline region in the oxide film 230f can be increased, and the in-plane inhomogeneity of the crystalline region in the oxide film 230f can be reduced. Consequently, the in-plane inhomogeneity of the transistor's electrical characteristics can be reduced.

[0279] Furthermore, by performing a heat treatment, oxygen can be supplied to the oxide film 230f, thereby reducing oxygen vacancies in the oxide film 230f. This improves the reliability of the transistor 200.

[0280] Furthermore, through heat treatment, hydrogen in insulator 216, insulating film 224f, and oxide film 230f moves to insulator 222 and is absorbed by insulator 222. In other words, hydrogen in insulator 216, insulating film 224f, and oxide film 230f diffuses to insulator 222. Therefore, although the hydrogen concentration in insulator 222 increases, the hydrogen concentration in insulator 216, insulating film 224f, and oxide film 230f decreases. Here, when insulator 221 is provided in contact with the bottom surface of insulator 222, impurities such as moisture or hydrogen can be prevented from entering from below insulator 221 due to the heat treatment.

[0281] In particular, the insulating film 224f (the rear insulator 224) is used as the second gate insulator of the transistor 200, and the oxide film 230f (the rear oxide 230) is used as the channel formation region of the transistor 200. The transistor 200 formed using the insulating film 224f and the oxide film 230f with reduced hydrogen concentration has excellent reliability and is therefore preferred.

[0282] Next, a conductive film 242f is deposited on the oxide film 230f (refer to...). Figure 10EThe conductive film 242f can be any conductive material corresponding to the conductors 242a and 242b described above. After depositing the oxide film 230f, the conductive film 242f is deposited on and in contact with the oxide film 230f without an etching process, thereby protecting the top surface of the oxide film 230f. As a result, the diffusion of impurities into the oxide 230 constituting the transistor can be reduced, thus improving the electrical characteristics and reliability of the semiconductor device.

[0283] The conductive film 242f can be deposited using sputtering, CVD, MBE, PLD or ALD methods.

[0284] In this embodiment, tantalum nitride is deposited as a conductive film 242f using a sputtering method. Alternatively, a heat treatment can be performed before depositing the conductive film 242f. This heat treatment can be performed under reduced pressure, wherein the conductive film 242f is continuously deposited without exposure to the atmosphere. By performing this treatment, moisture and hydrogen adsorbed on the surface of the oxide 230 can be removed, and the moisture and hydrogen concentrations in the oxide 230 can be reduced. The heat treatment temperature is preferably 100°C or higher and 400°C or lower.

[0285] Next, an insulating film 271f is deposited on the conductive film 242f (refer to...). Figure 10E The insulating film 271f can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD. Preferably, the insulating film 271f is an insulating film that inhibits oxygen permeation. For example, the insulating film 271f can be a stack of a silicon nitride film and a silicon oxide film deposited on the silicon nitride film using sputtering. By adopting this structure, the insulator 271a (insulator 271b) can have a stacked structure of an insulator 271a1 (insulator 271b1) made of silicon nitride and an insulator 271a2 (insulator 271b2) made of silicon oxide.

[0286] Here, when a multilayer film is used as the insulating film 271f, deposition is performed continuously without exposure to the atmospheric environment. By performing deposition without exposure to the atmosphere, the interface or vicinity of the multilayer film of the insulating film 271f can be kept clean. Furthermore, it is more preferable to continuously deposit the conductive film 242f onto the insulating film 271f without exposure to the atmosphere.

[0287] Alternatively, a heat treatment can be performed before depositing the insulating film 271f. This heat treatment can also be performed under reduced pressure, wherein the insulating film 271f is continuously deposited without exposure to the atmosphere. By performing this treatment, moisture and hydrogen adsorbed on the surface of the conductive film 242f can be removed, and the moisture and hydrogen concentrations in the conductive film 242f can be reduced. The heat treatment temperature is preferably 100°C or higher and 400°C or lower.

[0288] Next, using photolithography, the insulating film 224f, oxide film 230f, conductive film 242f, and insulating film 271f are processed into islands to form insulator 224, oxide 230, conductor 242A, and insulator 271A (see reference). Figure 11A ).

[0289] The above processing can be performed using either dry etching or wet etching. Dry etching is suitable for microfabrication. Furthermore, the processing of the insulating film 224f, oxide film 230f, conductive film 242f, and insulating film 271f can also be performed under different conditions.

[0290] Here, it is preferable to process insulator 224, oxide 230, conductor 242A, and insulator 271A into an island shape in one step. In this case, the side end of conductor 242A is preferably aligned or substantially aligned with the side end of oxide 230. Furthermore, the side end of insulator 224 is preferably aligned or substantially aligned with the side end of oxide 230. Additionally, the side end of insulator 271A is preferably aligned or substantially aligned with the side end of conductor 242A. By adopting the above structure, the number of steps in the semiconductor device according to one aspect of the present invention can be reduced. Thus, a method for manufacturing a semiconductor device with high productivity can be provided.

[0291] Furthermore, insulator 224, oxide 230, conductor 242A, and insulator 271A are formed such that at least a portion of them overlap with conductor 205. Additionally, in regions where they do not overlap with insulator 224, oxide 230, conductor 242A, and insulator 271A, insulator 222 is exposed. However, this is not a limitation; a structure in which insulator 224 remains on insulator 222 in regions not overlapping with oxide 230 may also be used. In this case, as... Figures 5A to 5D Like transistor 200, insulator 224 is partially formed in an open shape rather than in an island shape.

[0292] like Figure 11A As shown, the sides of insulator 224, oxide 230, conductor 242A, and insulator 271A can also have a conical shape. The cone angle of the sides of insulator 224, oxide 230, conductor 242A, and insulator 271A can, for example, be 60° or more and less than 90°. Thus, when the sides have a conical shape, the coverage of insulator 275, etc., is improved in subsequent processes, and defects such as voids can be reduced.

[0293] Alternatively, the sides of insulator 224, oxide 230, conductor 242A, and insulator 271A can be perpendicular or substantially perpendicular to the top surface of insulator 222. This structure allows for smaller area and higher density when multiple transistors are arranged.

[0294] Note that in lithography, the photoresist is first exposed through a mask. Then, a developer is used to remove or leave the exposed areas, forming a photoresist mask. Next, etching is performed through this photoresist mask to process conductors, semiconductors, or insulators into the desired shape. For example, a KrF stimulated excimer laser, an ArF stimulated excimer laser, or EUV (Extreme Ultraviolet) light can be used to expose the photoresist mask to form it. Alternatively, immersion lithography can be used, where exposure is performed with the substrate and projection lens filled with a liquid (e.g., water). Electron beams or ion beams can also be used instead of the aforementioned light. Furthermore, when using electron beams or ion beams, sometimes a mask is not required. Unwanted resist masks after processing can be removed by dry etching (sometimes referred to as oxygen plasma treatment) or wet etching, or wet etching followed by dry etching or dry etching followed by wet etching.

[0296] Furthermore, a hard mask made of an insulator or conductor can also be used under a photoresist mask. When using a hard mask, an insulating film or conductive film that serves as the hard mask material can be formed on the insulating film 271f, and a photoresist mask can be formed on it. Then, the hard mask material can be etched to form a hard mask of the desired shape. For example, tungsten can also be used as the hard mask material. The etching of the insulating film 271f, etc., can be performed either after removing the photoresist mask or without removing the photoresist mask. In the latter case, the photoresist mask may sometimes disappear during etching. The hard mask can also be removed by etching after etching the oxide film 230f, etc. On the other hand, if the hard mask material does not affect subsequent processes or can be used in subsequent processes, it is not necessarily necessary to remove the hard mask.

[0297] Alternatively, SOC (Spin On Carbon) films and SOG (Spin On Glass) films can be deposited between the workpiece and the resist mask. Using SOC and SOG films as masks improves the adhesion between the workpiece and the resist mask, thereby enhancing the durability of the mask pattern. For example, lithography can be performed by sequentially depositing SOC, SOG, and the resist mask on the workpiece.

[0298] As the etching gas for dry etching, halogen-containing etching gases can be used; specifically, etching gases containing one or more of fluorine, chlorine, and bromine can be used. Examples of etching gases include one or more mixtures of C4F6, C5F6, C4F8, CF4, SF6, CHF3, CH2F2, C12, BCl3, SiCl4, and BBr3. Additionally, oxygen, carbon dioxide, nitrogen, helium, argon, hydrogen, or hydrocarbon gases can be appropriately added to the above etching gases. Furthermore, depending on the material being dry-etched, gases containing hydrocarbons or hydrogen but not halogens can also be used as etching gases. Hydrocarbons used as etching gases include methane (CH4), ethane (C2H6), propane (C3H8), and butane (C4H4H6). 10 One or more of the following: ethylene (C2H4), propylene (C3H6), acetylene (C2H2), and propyne (C3H4). Etching conditions can be appropriately set according to the object being etched.

[0299] Additionally, as a dry etching apparatus, a capacitively coupled plasma (CCP) etching apparatus including parallel planar electrodes can be used. This CCP etching apparatus can also employ a structure where a high-frequency voltage is applied to one of the parallel planar electrodes. Alternatively, it can employ a structure where a high-frequency voltage of the same frequency is applied to each of the parallel planar electrodes. Furthermore, it can employ a structure where multiple different high-frequency voltages are applied to the parallel planar electrodes. This type of CCP etching apparatus is called a dual-frequency capacitively coupled plasma (DF-CCP) etching apparatus. The DF-CCP etching apparatus can also employ a structure where a high-frequency voltage of different frequencies is applied to each of the parallel planar electrodes. Alternatively, it can employ a structure where multiple different high-frequency voltages are applied to one of the parallel planar electrodes. Alternatively, a dry etching apparatus with a high-density plasma source can be used. For example, an inductively coupled plasma (ICP) etching apparatus can be used as a dry etching apparatus with a high-density plasma source. The etching apparatus can be appropriately configured according to the object to be etched. Note that in the aforementioned dry etching apparatus, reactive ion etching can be performed by generating a self-biased potential by applying a high-frequency voltage to an electrode on one side of the substrate. In reactive ion etching, etching is performed by accelerating ions in the plasma to collide with the workpiece, thus enabling highly anisotropic etching processes.

[0300] Furthermore, in the aforementioned etching process, the insulator 271A can also be used as an etch stop layer to protect the conductor 242A. For example, when a hard metal mask is formed on the insulator 271A in the aforementioned etching process, it is sometimes difficult to obtain an etch selectivity ratio with the conductor 242A when the hard mask is removed. However, by forming the insulator 271A on the conductor 242A, the insulator 271A can be used as an etch stop layer to protect the conductor 242A during the etching process after removing the hard mask. This prevents the formation of a curved surface between the side and top surfaces of the conductor 242A, thus... Figure 1D The conductors 242a and 242b formed laterally have sharp edges at the intersection of their side and top surfaces. When the intersection of the side and top surfaces of conductor 242A has sharp edges, the cross-sectional area of ​​conductor 242A increases compared to the case where the end has a curved surface. Furthermore, by using a nitride insulator, which is less prone to metal oxidation, as the insulator 271A, excessive oxidation of conductor 242A can be prevented. As a result, the resistance of conductors 242a and 242b decreases, thus increasing the transistor's on-state current.

[0301] Furthermore, by processing insulator 224 into an island shape, insulator 275 can be provided in a manner that contacts the side surface of insulator 224 and the top surface of insulator 222 in the later described process. That is, insulator 275 can separate insulator 224 from insulator 280. With this structure, excessive impurities such as oxygen and hydrogen can be prevented from mixing into oxide 230 from insulator 280 through insulator 224.

[0302] Next, insulator 275 is deposited in a manner that covers insulator 224, oxide 230, conductor 242A and insulator 271A, and insulator 280 is deposited on insulator 275 (see reference). Figure 11B The above-mentioned insulating materials can be used as insulators 275 and 280.

[0303] Here, insulator 275 is preferably in contact with the top surface of insulator 222.

[0304] As the insulator 280, it is preferable to form an insulating film that will become the insulator 280 by CMP treatment of the insulating film, thereby forming an insulator with a flat top surface. Alternatively, silicon nitride can be deposited on the insulator 280, for example, by sputtering, and CMP treatment can be performed on the silicon nitride until it reaches the insulator 280.

[0305] Insulators 275 and 280 can each be deposited, for example, by sputtering, CVD, MBE, PLD or ALD.

[0306] The insulator 275 is preferably an insulator that inhibits oxygen permeation. For example, silicon nitride is preferably deposited using the PEALD method as the insulator 275. Alternatively, aluminum oxide can be deposited using sputtering and silicon nitride can be deposited on it using the PEALD method. When the insulator 275 has the above-described structure, the function of inhibiting the diffusion of impurities such as water and hydrogen, as well as oxygen, can be improved.

[0307] Thus, the oxide 230 and the conductor 242A can be covered by an insulator 275 that has the function of inhibiting oxygen diffusion. As a result, oxygen can be prevented from diffusing directly from the insulator 280 and the like into the oxide 230 and the conductor 242A in subsequent processes.

[0308] Furthermore, silicon oxide is preferably deposited using sputtering as the insulator 280. By depositing the insulating film that will become the insulator 280 using sputtering under an oxygen-containing atmosphere, an insulator 280 containing excess oxygen can be formed. By using a sputtering method that does not require the use of hydrogen-containing molecules as the deposition gas, the hydrogen concentration in the insulator 280 can be reduced. In addition, a heat treatment can be performed before depositing the insulating film. This heat treatment can also be performed under reduced pressure, wherein the insulating film is continuously deposited without exposure to the atmosphere. By performing this treatment, moisture and hydrogen adsorbed on the surface of the insulator 275 can be removed. The heat treatment can be performed under the conditions described above.

[0309] Next, photolithography is used to process conductor 242A, insulator 271A, insulator 275, and insulator 280 to form openings reaching oxide 230 and insulator 222 (see reference). Figure 11C Here, conductor 242A2 is divided to form conductor 242a and conductor 242b, and insulator 271A is divided to form insulator 271a and insulator 271b. The openings formed in insulator 280 and insulator 275 overlap with oxide 230 and conductor 205.

[0310] Lithography can appropriately utilize the methods described above. To fabricate a fine opening in the insulator 280, lithography using short-wavelength light such as EUV light or electron beams is preferred. For example, lithography can be used... Figures 12A1 to 12D2 The method shown forms an opening in the insulator 280 to form conductors 242a and 242b.

[0311] First, a coating film 277 is deposited on the insulator 280, and a coating film 278 is deposited (see reference). Figure 12A1 and Figure 12A2Coating films 277 and 278 can also improve the adhesion between the resist mask and the insulator 280 (described later). The deposition of coating films 277 and 278 can be performed, for example, by spin coating. Non-photosensitive organic resins can be used as coating films 277 and 278.

[0312] Here, the coating film 278 is used as a mask in the etching process of the coating film 277. Therefore, under the etching conditions of the coating film 277, the etching rate of the coating film 278 is preferably lower than the etching rate of the coating film 277. For example, the coating film 277 can be set as a carbon-containing film, and the coating film 278 can be set as a silicon and carbon-containing film. In this embodiment, an SOC (Spin On Carbon) film is deposited as the coating film 277, and an SOG (Spin On Glass) film is deposited as the coating film 278.

[0313] Note that coating films 277 and 278 contain organic solvents such as alcohols during coating, but the organic matter may be reduced or removed in subsequent processes or when the semiconductor device is completed. Furthermore, the coating film can be provided as needed; a single-layer coating film may be provided, or no coating film may be provided if the resist mask described later is sufficient.

[0314] Next, a resist mask 279 with openings is formed on the coated film 278 using photolithography (see reference). Figure 12A1 and Figure 12A2 The photoresist mask 279 can be formed, for example, by exposing the photoresist to KrF stimulated excimer laser, ArF stimulated excimer laser, EUV (Extreme Ultraviolet) light. Alternatively, immersion technology can be used, where exposure is performed with the substrate and projection lens filled with a liquid (e.g., water). Furthermore, electron beams or ion beams can be used instead of the aforementioned light. Note that when using electron beams or ion beams, a photomask may sometimes be omitted.

[0315] The following is based on Figures 12B1 to 12D2 In this process, dry etching is preferably used to process the workpiece. Dry etching allows for anisotropic etching, making it suitable for creating openings with high aspect ratios. When performing anisotropic etching, reactive ion etching is preferred, for example. Note that the dry etching conditions and apparatus can be found above. Note that according to... Figures 12B1 to 12D2 The process is preferably carried out continuously without exposure to the atmosphere. For example, a multi-chamber etching apparatus can be used to carry out the process continuously without exposure to the atmosphere.

[0316] First, the coating film 278 is processed using a resist mask 279 to form a coating film 278 with openings. For example, when an SOG film is used for the coating film 278, an DF-CCP etching apparatus can be used and CF4 can be used as the etching gas for etching.

[0317] Next, using the coating film 278 as a mask, the coating film 277 is processed to form a coating film 277 with openings (see reference). Figure 12B1 and Figure 12B2 For example, when using an SOG film as coating film 277, a DF-CCP etching apparatus can be used, and H2 and N2 can be used as etching gases for etching. Here, since an SOG film is used as coating film 278, it is possible to prevent the coating film 278 from disappearing during the etching process of coating film 277.

[0318] Furthermore, it is preferable to remove the resist mask 279 simultaneously during the processing of the coating film 277. Since a SOC film is used as the coating film 277, the resist mask 279 can be easily removed. In addition, if the resist mask 279 remains after the coating film 277 is formed, it is preferable to remove the resist mask 279.

[0319] Next, the coating film 277 is used as a mask to process the insulator 280 to form an insulator 280 with openings. For example, when a silicon oxide film is used for the insulator 280, an DF-CCP etching apparatus can be used and C4F8, C4F6, O2 and Ar can be used as etching gases for etching.

[0320] Furthermore, the coating film 277 is used as a mask to process the insulators 275 and 271A to form insulators 275, 271a, and 271b with openings (see reference). Figure 12C1 and Figure 12C2 For example, when using silicon oxide and silicon nitride films for insulators 275 and 271A, a DF-CCP etching apparatus can be used, and CH2F2, O2, and Ar can be used as etching gases for etching. In this case, conductor 242A and insulator 222 can be used as etching stop layers. Furthermore, it is preferable to remove the coating film 278 simultaneously with the processing of insulators 275 and 271A.

[0321] Preferably, the coating film 277 is removed by a dry etching process, such as ashing with oxygen plasma, after the insulators 271a and 271b are formed. However, it is not limited to this, and the coating film 277 may also be removed after the conductors 242a and 242b are formed.

[0322] Next, the insulator 280 is preferably used as a mask to remove the surface oxide film of the conductor 242A. For example, when using a tantalum nitride film for the conductor 242A, an ICP etching apparatus can be used and BCl3 and Cl2 can be used as etching gases for etching.

[0323] Furthermore, the insulator 280 is used as a mask to process the conductor 242A to form conductors 242a and 242b (see reference). Figure 12D1 and Figure 12D2 For example, when using a tantalum nitride film for conductor 242A, an ICP etching apparatus can be used, and Cl2 and Ar can be used as etching gases for etching. In this case, oxide 230 and insulator 222 can be used as etching stop layers. At this time, as... Figure 12D2 As shown, when viewed in cross-section along the channel width direction of transistor 200, there is sometimes a curved surface between the side surface and the top surface of oxide 230. That is, sometimes the ends of the side surface and the ends of the top surface are rounded.

[0324] Sometimes, a recess is formed in the portion of oxide 230 exposed from conductors 242a and 242b. In other words, the height of the region between conductors 242a and 242b on the top surface of oxide 230 is sometimes smaller than the region overlapping with conductors 242a and 242b.

[0325] Through the above steps, openings can be formed in insulators 275 and 280, and insulators 271a, 271b, conductors 242a and 242b can be formed.

[0326] After the conductor 242A is processed, an ashing treatment using oxygen plasma can be performed. This oxygen plasma treatment removes impurities that diffused into the oxide 230 and the like during the etching process described above. Examples of such impurities include those originating from components in the workpiece subjected to the etching process and those originating from components in the gases used in the etching process. Examples include chlorine, fluorine, tantalum, silicon, and hafnium. By removing impurities adhering to the oxide 230 in this way, the electrical characteristics and reliability of the transistor can be improved.

[0327] Furthermore, the processing of the conductor 242A and the oxygen plasma treatment can be performed continuously without exposure to the atmosphere. For example, this can be achieved using a multi-chamber etching apparatus without exposure to the atmosphere.

[0328] To remove impurities and other contaminants that adhere to the surface of oxide 230 during the etching process described above, a washing process is preferable. Washing methods include wet washing (also known as wet etching) using a washing solution, plasma treatment using plasma, and washing using heat treatment; combinations of these methods may also be appropriate. Note that this washing process may sometimes deepen the aforementioned tank area.

[0329] Wet washing can also be performed using an aqueous solution prepared by diluting one or more of oxalic acid, phosphoric acid, and hydrofluoric acid with carbonated water or pure water. Alternatively, wet washing can be performed using an aqueous solution prepared by diluting ammonia with carbonated water or pure water. Furthermore, wet washing can also be performed using pure water or carbonated water. Alternatively, ultrasonic washing can be performed using the aforementioned aqueous solutions, pure water, or carbonated water. Furthermore, the above washing methods can be appropriately combined.

[0330] Note that in this specification, the aqueous solution of hydrofluoric acid diluted with pure water is sometimes referred to as dilute hydrofluoric acid, and the aqueous solution of ammonia diluted with pure water is sometimes referred to as dilute ammonia. Furthermore, the concentration, temperature, etc., of this aqueous solution are appropriately adjusted according to the impurities to be removed and the structure of the semiconductor device being cleaned. The ammonia concentration of the dilute ammonia is preferably set to 0.01% or more and 5% or less, more preferably 0.1% or more and 0.5% or less. Furthermore, the hydrogen fluoride concentration of the dilute hydrofluoric acid is preferably set to 0.01 ppm or more and 100 ppm or less, more preferably 0.1 ppm or more and 10 ppm or less.

[0331] Furthermore, for ultrasonic cleaning, a frequency of 200 kHz or higher is preferred, and a frequency of 900 kHz or higher is even more preferred. By using this frequency, damage to oxides 230 and the like can be reduced.

[0332] Furthermore, the above washing process can be performed multiple times, or the washing solution can be changed for each washing process. For example, the first washing process can be performed using dilute hydrofluoric acid or dilute ammonia, and the second washing process can be performed using pure water or carbonated water.

[0333] In this embodiment, a wet wash is performed using carbonated water as the washing process described above. This washing process removes impurities adhering to the surface of the oxide 230 or diffused into its interior. Furthermore, it also removes the surface layer of the oxide 230 that was damaged during the etching process described above.

[0334] The heat treatment is preferably performed after the etching or washing described above. The temperature of the heat treatment is 100°C or higher and 650°C or lower, preferably 250°C or higher and 600°C or lower, more preferably 300°C or higher and 550°C or lower, and even more preferably 350°C or higher and 400°C or lower. The heat treatment is performed in an atmosphere containing nitrogen, an inert gas, or an oxidizing gas containing 10 ppm or higher, 1% or higher, or 10% or higher. For example, it is preferable to perform the heat treatment in an oxygen-containing atmosphere, preferably at a nitrogen to oxygen gas flow ratio of 4:1 and at a temperature of 350°C for 1 hour. This supplies oxygen to the oxide 230, thereby reducing oxygen vacancies. Furthermore, the crystallinity of the oxide 230 can be improved by performing the above heat treatment. Moreover, when residual hydrogen in the oxide 230 reacts with the supplied oxygen, the hydrogen can be removed in the form of H2O (dehydration). This suppresses the recombination of residual hydrogen and oxygen vacancies in the oxide 230 to form V. O H. This improves the electrical characteristics of the transistor with oxide 230, thereby increasing its reliability. Furthermore, it suppresses the inhomogeneity of electrical characteristics among multiple transistors formed on the same substrate. The above-described heat treatment can also be performed under reduced pressure. Alternatively, the heat treatment can be performed in an oxygen atmosphere, followed by continuous heat treatment in a nitrogen atmosphere without exposure to the atmosphere.

[0335] When heat treatment is performed while the conductors 242a and 242b are in contact with the oxide 230, the sheet resistance of the regions of oxide 230 overlapping with conductor 242a and oxide 230 overlapping with conductor 242b sometimes decreases. Additionally, the carrier concentration sometimes increases. Therefore, it is possible to self-align and reduce the resistance of the regions of oxide 230 overlapping with conductor 242a and oxide 230 overlapping with conductor 242b.

[0336] Next, an insulating film 250f, which will become the insulator 250, is deposited in a manner that covers the openings formed in the insulator 280, etc. (see reference). Figure 13A Here, insulating film 250f is deposited along the openings of insulator 280 and insulator 275. Insulating film 250f is in contact with insulator 280, conductor 242a, conductor 242b, insulator 222, insulator 224 and oxide 230.

[0337] The insulating film 250f can be deposited using sputtering, CVD, MBE, PLD, or ALD methods. For example, the insulating film 250f is preferably deposited using the ALD method. The insulating film 250f is preferably formed thin, and thickness non-uniformity needs to be minimized. For this purpose, the ALD method is a deposition method that alternately introduces precursors and reactants (e.g., oxidants). Since the film thickness can be adjusted according to the number of cycles, the thickness can be precisely controlled. Furthermore, the insulating film 250f needs to be deposited with high coverage on the bottom and sides of the opening. By using the ALD method, atomic layers can be deposited on the bottom and sides of the opening, thus forming the insulating film 250f with high coverage within the opening.

[0338] Furthermore, when depositing the insulating film 250f using the ALD method, ozone (O3), oxygen (O2), water (H2O), etc., can be used as oxidants. By using ozone (O3), oxygen (O2), etc., which do not contain hydrogen, as oxidants, the amount of hydrogen diffusing into the oxide 230 can be reduced. like Figure 3B As shown, the insulator 250 can have a multilayer structure. The following describes the insulator 250 and... Figure 3B Similarly, a deposition method for insulating film 250f when having a four-layer structure of insulator 250a, insulator 250b, insulator 250c and insulator 250d.

[0340] First, a film that will become insulator 250a is deposited to cover the openings formed in insulator 280, etc., and then a film that will become insulator 250b is deposited on the film that will become insulator 250a. In this embodiment, aluminum oxide is deposited as the film that will become insulator 250a using the thermal ALD method, and silicon oxide is deposited as the film that will become insulator 250b using the PEALD method.

[0341] Next, microwave processing is preferably performed in an oxygen-containing atmosphere. Here, microwave processing refers, for example, to processing using a device that includes a power source for generating high-density plasma using microwaves. Furthermore, in this specification, microwaves refer to electromagnetic waves with a frequency of 300 MHz or higher and 300 GHz or lower.

[0342] Microwave processing preferably utilizes a microwave processing apparatus, for example, that includes a power supply for generating high-density plasma using microwaves. Here, the frequency of the microwave processing apparatus is preferably set to 300 MHz or more and 300 GHz or less, more preferably 2.4 GHz or more and 2.5 GHz or less, for example, 2.45 GHz. By using high-density plasma, a high density of oxygen free radicals can be generated. Furthermore, the power of the power supply for applying microwaves to the microwave processing apparatus is preferably 1000 W or more and 10000 W or less, more preferably 2000 W or more and 5000 W or less. Additionally, the microwave processing apparatus may also include a power supply that applies RF to one side of the substrate. Furthermore, by applying RF to one side of the substrate, oxygen ions generated by the high-density plasma can be efficiently introduced into the oxide 230.

[0343] Furthermore, the aforementioned microwave treatment is preferably performed under reduced pressure, preferably between 10 Pa and 1000 Pa, more preferably between 300 Pa and 700 Pa. The treatment temperature is preferably below 750°C, more preferably below 500°C, for example, around 250°C. Alternatively, heating treatment can be performed continuously after oxygen plasma treatment without exposure to external air. The heating temperature is preferably between 100°C and 750°C, more preferably between 300°C and 500°C.

[0344] Alternatively, for example, the microwave treatment described above can be performed using oxygen gas and argon gas. Here, the oxygen flow ratio (O2 / (O2+Ar)) is greater than 0% and less than 100%. Preferably, the oxygen flow ratio (O2 / (O2+Ar)) is greater than 0% and less than 50%. More preferably, the oxygen flow ratio (O2 / (O2+Ar)) is more than 10% and less than 40%. Even more preferably, the oxygen flow ratio (O2 / (O2+Ar)) is more than 10% and less than 30%. In this way, by performing microwave treatment in an oxygen-containing atmosphere, the carrier concentration in the region of oxide 230 exposed from the opening can be reduced. In addition, by preventing excessive oxygen from being introduced into the treatment chamber during microwave treatment, an excessive decrease in the carrier concentration in oxide 230 can be prevented.

[0345] By performing microwave treatment in an oxygen-containing atmosphere, oxygen gas can be plasmaized using microwaves or high frequencies such as RF, and this oxygen plasma can then act on the region between conductors 242a and 242b of oxide 230. Through the action of plasma, microwaves, etc., the V in this region can be... O H separates into oxygen vacancies and hydrogen, and hydrogen is removed from this region. Here, in the use of Figure 3BWhen using the structure shown, as the membrane that will serve as insulator 250a, it is preferable to use an insulating membrane (e.g., alumina, etc.) that has the function of trapping or fixing hydrogen. By adopting the above structure, the membrane that will serve as insulator 250a can trap or fix the hydrogen generated by microwave processing. In this way, the V contained in the channel forming region can be reduced. O H. This can reduce oxygen vacancies and V in the channel formation region. O H reduces carrier concentration. Furthermore, by supplying oxygen free radicals generated in the aforementioned oxygen plasma to the oxygen vacancies formed in the channel formation region, the oxygen vacancies in the channel formation region can be further reduced, thereby reducing carrier concentration.

[0346] The oxygen injected into the channel formation region can be in various forms, including oxygen atoms, oxygen molecules, oxygen ions, and oxygen free radicals (also known as O free radicals, which are atoms, molecules, or ions containing unpaired electrons). The oxygen injected into the channel formation region can be any one or more of the above forms, with oxygen free radicals being particularly preferred. Furthermore, since the film quality of the insulator 250 can be improved, the reliability of the transistor is enhanced.

[0347] On the other hand, the oxide 230 has a region that overlaps with either conductor 242a or conductor 242b. This region can be used as a source region or a drain region. Here, conductor 242a and conductor 242b are preferably used as shielding films to protect against the effects of microwaves, RF, or oxygen plasma during microwave processing in an oxygen-containing atmosphere. Thus, conductor 242a and conductor 242b preferably have the function of shielding electromagnetic waves of 300 MHz or higher and 300 GHz or lower, for example, 2.4 GHz or higher and 2.5 GHz or lower.

[0348] Conductors 242a and 242b shield against the effects of high-frequency microwaves or RF, oxygen plasma, etc., and therefore do not act on the region of oxide 230 that overlaps with either conductor 242a or conductor 242b. Thus, Vo does not occur in the source and drain regions by microwave processing. O The decrease in H and the excessive supply of oxygen can prevent the decrease in carrier concentration.

[0349] As described above, oxygen vacancies and V can be selectively removed in the channel formation region of an oxide semiconductor. O H makes the channel formation region i-type or substantially i-type. Furthermore, it can suppress the supply of excessive oxygen to the regions used as source or drain regions, maintaining the conductivity (low resistance region state) before microwave processing. Thus, it can suppress variations in the electrical characteristics of the transistor and suppress non-uniformity of the transistor's electrical characteristics within the substrate surface.

[0350] Furthermore, by modifying the film quality of the films that will become insulator 250a and insulator 250b through microwave treatment, the diffusion of hydrogen, water, impurities, etc., can be suppressed. This suppresses the diffusion of hydrogen, water, impurities, etc., through insulator 250 to oxide 230 and the like, which occurs after subsequent processes such as deposition of the conductive film that will become conductor 260 or after heat treatment. Thus, by improving the film quality of insulator 250, the reliability of the transistor can be improved.

[0351] Next, a film that will become insulator 250d is deposited on the film that will become insulator 250b. In this embodiment, hafnium oxide is deposited using the thermal ALD method as the film that will become insulator 250d. Alternatively, microwave treatment may be performed again after depositing the film that will become insulator 250d.

[0352] Next, a film that will become insulator 250c is deposited on the film that will become insulator 250d. In this embodiment, silicon nitride is deposited using the PEALD method as the film that will become insulator 250c. In this way, an insulating film 250f comprising films that will become insulator 250a to films that will become insulator 250d can be formed.

[0353] Note that the above structure shows an example of microwave treatment performed after the deposition of the film that will become insulator 250b and after the deposition of the film that will become insulator 250d, but the present invention is not limited thereto. Microwave treatment may also be performed after the deposition of the film that will become insulator 250c. Alternatively, microwave treatment may be performed before the deposition of the film that will become insulator 250a. Furthermore, microwave treatment may be performed three or more times.

[0354] Alternatively, heating treatment can be performed while maintaining a reduced pressure after microwave treatment. This treatment efficiently removes hydrogen from the oxide 230 in the insulating film. Furthermore, the step of performing heating treatment while maintaining a reduced pressure after microwave treatment can be repeated. Repeated heating treatment further efficiently removes hydrogen from the oxide 230 in the insulating film. Note that the heating treatment temperature is preferably 300°C or higher and 500°C or lower.

[0355] Next, a conductive film 260f (refer to) will be deposited to become the conductor 260. Figure 13B The conductive film 260f can be deposited using the aforementioned conductive materials via sputtering, CVD, MBE, PLD, electroplating, or ALD methods. For example, it can be deposited by stacking titanium nitride and tungsten films using CVD. Figure 3A As shown, the conductor 260 may have a stacked structure of a conductor 260a made of titanium nitride and a conductor 260b made of tungsten.

[0356] Next, the insulating film 250f and conductive film 260f are polished using CMP until the insulator 280 is exposed. That is, a portion of the insulating film 250f and conductive film 260f exposed from the opening is removed. Thus, the insulator 250 and conductor 260 (conductor 260a and conductor 260b) are formed in the opening overlapping with the conductor 205 (see reference). Figure 13C ).

[0357] Thus, the insulator 250 is disposed in contact with the conductors 242a, 242b, oxide 230, insulator 224, and insulator 222 within the aforementioned opening. Furthermore, the conductor 260 is disposed such that it is embedded in the aforementioned opening with the insulator 250 in between. This forms the transistor 200.

[0358] Next, insulator 282a is deposited on insulator 250, conductor 260 and insulator 280 (see reference). Figure 14A The insulator 282a is preferably deposited using the ALD method. In this embodiment, alumina is preferably deposited using the thermal ALD method as the insulator 282a. Here, the thickness of the insulator 282a is preferably 1 nm or more and 20 nm or less, more preferably 3 nm or more and 10 nm or less.

[0359] By using the ALD method to deposit insulator 282a, insulator 282a can be deposited without causing excessive damage to the surface to be formed. Therefore, excessive damage to the upper end of insulator 250 and the top surface of conductor 260 can be prevented, thereby improving the electrical characteristics and reliability of transistor 200.

[0360] Furthermore, by using the ALD method to deposit insulator 282a, insulator 282a can be deposited without adding oxygen to insulator 280. This prevents the addition of excessive oxygen to insulator 280. Therefore, the electrical characteristics and reliability of transistor 200 can be improved.

[0361] Next, insulator 282b is formed on insulator 282a (see reference). Figure 14B Insulator 282b is preferably deposited using a sputtering method. By utilizing a sputtering method that does not require the use of hydrogen-containing molecules as the deposition gas, the hydrogen concentration in insulator 282 can be reduced.

[0362] Here, by depositing insulator 282b in an oxygen-containing atmosphere using sputtering, oxygen can be added to insulator 280 simultaneously with the deposition. This allows insulator 280 to contain excess oxygen. Preferably, insulator 282b is deposited while the substrate is heated. Since insulator 282b is deposited on insulator 282a and oxygen is added through insulator 282a, the amount of oxygen injected into insulator 280 can be controlled. When the thickness of insulator 282a is large, the aforementioned oxygen addition is easily hindered, resulting in a decrease in the amount of oxygen injected into insulator 280. When the thickness of insulator 282a is small, the aforementioned oxygen addition is not easily hindered, resulting in an increase in the amount of oxygen injected into insulator 280. For example, by setting the thickness of insulator 282a within the aforementioned range, a sufficient amount of oxygen can be supplied to oxide 230, and excessive oxygen supply to oxide 230 can be prevented. This improves the electrical characteristics and reliability of transistor 200. In addition, when depositing the insulator 282b, oxygen can be added not only to the insulator 280 but also to the upper end of the insulator 250.

[0363] Furthermore, by depositing insulator 282b on insulator 282a, the upper end of insulator 250 and the top surface of conductor 260 can be protected from the impact of ion collisions generated by the sputtering deposition of insulator 282b.

[0364] In this embodiment, alumina is deposited as insulator 282b using sputtering. Alumina is deposited using an aluminum target in an atmosphere containing oxygen gas. The amount of oxygen injected into insulator 280 can be controlled according to the magnitude of the bias power applied to the substrate by sputtering. For example, the lower the bias power, the less oxygen is injected into insulator 280, and the oxygen content is easily saturated even if the thickness of insulator 282b is small. Conversely, the higher the bias power, the more oxygen is injected into insulator 280. By reducing the RF power, the amount of oxygen injected into insulator 280 can be suppressed. Note that when applying substrate bias using an RF power supply, the RF frequency is preferably 10 MHz or higher. Typically, it is 13.56 MHz. The higher the RF frequency, the less damage to the substrate can be caused.

[0365] Furthermore, a heat treatment can be performed before depositing the insulator 282b. This heat treatment can also be performed under reduced pressure, wherein the insulator 282b is deposited continuously without exposure to the atmosphere. By performing this treatment, moisture and hydrogen adsorbed on the surface of the insulator 280 can be captured or fixed by the insulator 282a, and the moisture and hydrogen concentrations in the insulator 280 are reduced. The temperature of the heat treatment is preferably 100°C or higher and 400°C or lower. In this embodiment, the temperature of the heat treatment is set to 250°C.

[0366] Next, insulator 283 is formed on insulator 282 (see reference). Figure 14C The insulator 283 can be deposited, for example, using sputtering, CVD, MBE, PLD, or ALD methods. Sputtering is preferred for depositing the insulator 283. By using sputtering, which does not require hydrogen-containing molecules to be used in the deposition gas, the hydrogen concentration in the insulator 283 can be reduced. In this embodiment, silicon nitride is deposited as the insulator 283 using sputtering. In this embodiment, silicon nitride is deposited as insulator 283 using sputtering, and aluminum oxide is deposited as insulator 282 using thermal ALD and sputtering. Thus, by using silicon nitride, which has the function of suppressing hydrogen diffusion, as insulator 283, hydrogen diffusion from the upper layer of transistor 200 can be suppressed. Furthermore, by using aluminum oxide, which has the function of trapping or fixing hydrogen, as insulator 282, hydrogen contained in insulator 280 and the like can be trapped or fixed by insulator 282. This reduces the hydrogen concentration in and around oxide 230.

[0368] Next, insulator 285 is formed on insulator 283 (see reference). Figure 14C The insulator 285 can be deposited, for example, using sputtering, CVD, MBE, PLD, or ALD methods. Sputtering is preferred for depositing the insulator 285. By using sputtering, which does not require hydrogen-containing molecules to be used in the deposition gas, the hydrogen concentration in the insulator 285 can be reduced. In this embodiment, silicon oxide is deposited as the insulator 285 using sputtering.

[0369] Here, it is preferable to continuously deposit insulators 282b, 283, and 285 using a sputtering method without exposing them to the atmospheric environment. By depositing in a manner that does not expose them to the atmosphere, impurities or moisture from the atmospheric environment can be prevented from adhering to insulators 282b, 283, and 285, thus keeping the interface or vicinity of insulators 282b and 283, as well as the interface or vicinity of insulators 283 and 285, clean.

[0370] Next, openings leading to conductor 242a are formed in insulators 271a, 275, 280, 282, 283, and 285, and openings leading to conductor 242b are formed in insulators 271b, 275, 280, 282, 283, and 285 (see reference). Figure 15AFurthermore, openings reaching the conductor 218 are formed in insulators 221, 222, 275, 280, 282, 283, and 285. These openings can be formed using lithography. When forming these openings, dry etching is preferably used on the workpiece. Dry etching allows for anisotropic etching, making it suitable for forming openings with high aspect ratios. When performing anisotropic etching, reactive ion etching is preferred, for example. The conditions and apparatus for dry etching can be found in previous descriptions. Additionally, the shape of the opening, when viewed from above, can be a circle, an ellipse, or a polygon, or a polygon with rounded corners.

[0371] Next, after forming the opening described above, a heat treatment is performed. The heat treatment temperature can be 100°C or higher and 600°C or lower, preferably 250°C or higher and 550°C or lower, more preferably 350°C or higher and 450°C or lower. The heat treatment is preferably performed in a nitrogen or inert gas atmosphere. Furthermore, since this heat treatment is performed with the conductors 242a and 242b exposed, it is preferable to perform it in an atmosphere that does not contain oxidizing gases or oxygen gases. For example, it is preferable to perform the heat treatment at 400°C for 1 hour in a nitrogen atmosphere. The above heat treatment can also be performed under reduced pressure. Through the above heat treatment, oxygen contained in the insulator 280 can be supplied to the oxide 230 through the insulator 250. As a result, oxygen vacancies in the channel formation region of the oxide 230 can be reduced.

[0372] Here, since the side of the insulator 280 is exposed in the aforementioned opening, the oxygen contained in the insulator 280 can be diffused outward by the aforementioned heat treatment, thereby controlling the amount of oxygen contained in the insulator 280. On the other hand, because the insulator 280 is provided with insulators 282 and 283, which have oxygen-blocking properties, oxygen does not diffuse outward from the top surface of the insulator 280. Thus, excessive oxygen can be prevented from diffusing outward from the insulator 280 and forming oxygen vacancies in the insulator 280. Furthermore, the oxide 230, conductor 242a, and conductor 242b are covered by the insulator 275. Thus, excessive oxygen can be prevented from directly diffusing from the insulator 280 to the oxide 230, conductor 242a, and conductor 242b during the aforementioned heat treatment.

[0373] As described above, during the deposition of insulator 282b, the amount of oxygen added to insulator 280 can be controlled by adding oxygen through insulator 282a. Furthermore, when oxygen diffuses outward from the side of insulator 280 using the aforementioned heat treatment, the amount of oxygen in insulator 280 can be more appropriate. Thus, by supplying oxygen to oxide 230 from insulator 280 with adjusted oxygen content, an appropriate amount of oxygen can be supplied to oxide 230. This reduces oxygen vacancies in oxide 230 and prevents excessive oxygen supply to oxide 230. Therefore, the electrical characteristics and reliability of transistor 200 can be improved. Moreover, the process of exposing the side of insulator 280 can also serve as the process of forming openings for embedding conductors 240a to 240c, thus simplifying the manufacturing process of the semiconductor device.

[0374] Furthermore, through the aforementioned heat treatment, hydrogen contained in insulators 280, 250, and oxide 230 moves to insulator 282 and is captured by it. In other words, hydrogen in insulators 280, 250, and oxide 230 diffuses into insulator 282. Therefore, although the hydrogen concentration in insulator 282 increases, the hydrogen concentrations in insulators 280, 250, and oxide 230 all decrease. Moreover, when insulator 283 is provided in contact with the top surface of insulator 282, impurities such as moisture or hydrogen can be prevented from entering from above insulator 283 during the heat treatment. Additionally, through the heat treatment, hydrogen contained in insulators 216, 224, and oxide 230 moves to insulator 222 and is captured by it. In other words, hydrogen in insulators 216, 224, and oxide 230 diffuses into insulator 222. Therefore, although the hydrogen concentration in insulator 222 increases, the hydrogen concentrations in insulators 216, 224, and oxide 230 all decrease. Here, when insulator 221 is provided in contact with the bottom surface of insulator 222, impurities such as moisture or hydrogen can be prevented from entering from below insulator 221 due to the heat treatment.

[0375] Next, an insulating film 241f, which will become the insulator 241, is deposited along the shape of the aforementioned opening (see reference). Figure 15B The insulating film 241f can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD. Since the insulating film 241f is deposited in an opening with a high aspect ratio, ALD deposition is preferred. As the insulating film 241f, an insulating film with oxygen-suppressing properties is preferred. For example, silicon nitride is preferably deposited using the PEALD method. Silicon nitride has high hydrogen barrier properties and is therefore preferred.

[0376] Next, anisotropic etching is performed on the insulating film 241f to form insulators 241a, 241b, and 241c (see reference). Figure 15C Here, insulator 241a is formed to cover the sidewall of the opening on conductor 242a, insulator 241b is formed to cover the sidewall of the opening on conductor 242b, and insulator 241c is formed to cover the sidewall of the opening on conductor 218. Anisotropic etching of the insulating film 241f can be performed using dry etching or similar methods. For example, reactive ion etching is preferred. By providing insulators 241a, 241b, and 241c on the sidewalls of the openings, oxygen permeation from the outside can be suppressed, and oxidation of the subsequently formed conductors 240a, 240b, and 240c can be prevented. Furthermore, impurities such as water and hydrogen contained in insulator 280 can be prevented from diffusing into conductors 240a, 240b, and 240c. Note that sometimes, due to this anisotropic etching, recesses are formed on a portion of the top surface of conductors 242a, 242b, and 218.

[0377] Next, conductive films that will become conductors 240a, 240b, and 240c are deposited. These conductive films preferably have a multilayer structure comprising conductors that suppress the permeation of impurities such as water and hydrogen. For example, a multilayer of tantalum nitride, titanium nitride, etc., with tungsten, molybdenum, copper, etc., can be used. The conductive films that will become conductors 240 can be deposited using methods such as sputtering, CVD, MBE, PLD, or ALD.

[0378] Next, a portion of the conductive film that will become conductors 240a, 240b, and 240c is removed by CMP processing, exposing the top surface of the insulator 285. As a result, the conductive film remains only at the opening, thereby forming conductors 240a, 240b, and 240c with flat top surfaces (see reference). Figure 2B Note that sometimes a portion of the top surface of insulator 285 is removed due to this CMP process.

[0379] Furthermore, it is preferable to perform the heat treatment after forming the conductors 240a, 240b, and 240c. This heat treatment can be performed according to... Figure 15A The heating process is performed under the same conditions. By performing this heating process, the amount of oxygen supplied to oxide 230 can be adjusted. As a result, the electrical characteristics and reliability of transistor 200 can be improved.

[0380] Through the above processes, it is possible to manufacture Figure 2B The semiconductor device shown.

[0381] The semiconductor device according to this embodiment includes an OS transistor. In this embodiment, by controlling the oxygen supplied to the oxide semiconductor layer of the OS transistor, a semiconductor device with good electrical characteristics, a semiconductor device with small non-uniformity of transistor electrical characteristics, a semiconductor device with large on-state current, and a semiconductor device with high reliability can be realized.

[0382] This embodiment can be appropriately combined with other embodiments and examples. Furthermore, in this specification, where multiple structural examples are shown in one embodiment, these structural examples can be appropriately combined.

[0383] (Implementation Method 2) In this embodiment, an example of the structure of a display device using a transistor according to one aspect of the present invention will be described.

[0384] The transistor of one aspect of the present invention can be formed into an extremely miniaturized form, so a display device using the transistor of one aspect of the present invention can be an extremely high-definition display device. For example, the display device of one aspect of the present invention can be used in the display section of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, and in the display section of VR devices such as head-mounted displays and AR devices such as glasses-type devices (HMDs).

[0385] [Display Module] Figure 16A A perspective view of display module 580 is shown. Display module 580 includes display device 500A and FPC 590. Note that the display panel included in display module 580 is not limited to display device 500A, but may also be display device 500B or display device 500C, which will be described later.

[0386] The display module 580 includes a substrate 591 and a substrate 592. The display module 580 includes a display section 581. The display section 581 is an area for displaying images.

[0387] Figure 16B A perspective view of one side of the structure of substrate 591 is shown. A circuit section 582, a pixel circuit section 583 on the circuit section 582, and a pixel section 584 on the pixel circuit section 583 are stacked on the substrate 591. Furthermore, a terminal section 585 for connecting to the FPC 590 is provided on a portion of the substrate 591 that does not overlap with the pixel section 584. The terminal section 585 is electrically connected to the circuit section 582 via a wiring section 586 composed of multiple wirings.

[0388] The pixel unit 584 includes a plurality of pixels 584a arranged periodically. Figure 16BThe right side shows an enlarged view of pixel 584a. Pixel 584a includes a light-emitting element 110R that emits red light, a light-emitting element 110G that emits green light, and a light-emitting element 110B that emits blue light.

[0389] The pixel circuit section 583 includes a plurality of pixel circuits 583a arranged periodically. One pixel circuit 583a controls the emission of light from the three light-emitting elements included in one pixel 584a. One pixel circuit 583a may include three circuits controlling the emission of light from one light-emitting element. For example, the pixel circuit 583a may have a structure with at least one selection transistor, one current control transistor (driving transistor), and a capacitor for each light-emitting element. In this case, the gate of the selection transistor is input with a gate signal, and the source is input with a source signal. Thus, an active matrix display panel can be realized.

[0390] The circuit section 582 includes circuitry for driving each pixel circuit 583a of the pixel circuit section 583. For example, it preferably includes one or both of a gate line driving circuit and a source line driving circuit. Furthermore, it may include at least one of an arithmetic circuit, a storage circuit, and a power supply circuit. Additionally, transistors disposed in the circuit section 582 may also constitute part of the pixel circuit 583a. That is, the pixel circuit 583a may be constituted by transistors included in the pixel circuit section 583 and transistors included in the circuit section 582.

[0391] The FPC590 is used for wiring to supply video signals and power potentials to the circuit section 582 from the outside. Additionally, ICs can be mounted on the FPC590.

[0392] The display module 580 can have a structure in which one or both of the pixel circuit section 583 and circuit section 582 are stacked on the lower side of the pixel section 584, so that the display section 581 can have an extremely high aperture ratio (effective display area ratio). For example, the aperture ratio of the display section 581 can be 40% or more and less than 100%, preferably 50% or more and less than 95%, more preferably 60% or more and less than 95%. In addition, the pixels 584a can be arranged in an extremely high density, thereby enabling the display section 581 to have extremely high resolution. For example, the display section 581 preferably has pixels 584a arranged in a resolution of 2000ppi or more, more preferably 3000ppi or more, further preferably 5000ppi or more, and even more preferably 6000ppi or more and less than 20000ppi or less or less than 30000ppi.

[0393] This display module 580 boasts extremely high resolution, making it suitable for use in VR devices such as head-mounted displays or AR devices such as glasses. For example, because the display module 580 features a highly detailed display section 581, even when the display section is magnified through a lens, the user cannot see any pixels, thus achieving a highly immersive display. Furthermore, the display module 580 can also be applied to electronic devices with relatively small display sections. For example, it is suitable for use in the display sections of wearable electronic devices such as watches.

[0394] [Display Device 500A] Figure 17 The display device 500A shown includes a substrate 201, a light-emitting element 110R, a light-emitting element 110G, a light-emitting element 110B, a capacitor 140, and a transistor 520.

[0395] Substrate 201 is equivalent to Figure 16A Substrate 591 in the middle.

[0396] Transistor 520 is a transistor that uses oxide semiconductor in the semiconductor layer forming the channel. Transistor 520 includes oxide 230, conductor 205, insulator 222, insulator 224, conductor 242a, conductor 242b, insulator 250, and conductor 260. Furthermore, insulators 212, 216, 222, 280, 282, 283, and 285 are sequentially formed on substrate 201 as interlayer films. Additionally, conductors 240 and 241 are formed inside openings formed in insulators 280, 282, 283, and 285.

[0397] As transistor 520, various transistors shown in Embodiment 1 can be used. Although in Figure 17 The transistor 520 is simplified, but it can still be used. Figure 3A The transistor 200 and its surrounding structure as described above. For example, such as... Figure 3A As shown, insulators that block impurities such as hydrogen can be provided on the upper and lower layers of the transistor. This prevents hydrogen contained in and near the substrate and the light-emitting element from diffusing into the transistor 520. Furthermore, by providing the insulator 241 to cover the side surface of the conductor 240, hydrogen contained in and near the light-emitting element can be prevented from diffusing through the conductor 240 to the insulator 280. Thus, a display device with high reliability can be provided. The conductor 240 and the insulator 241 correspond to the conductors 240a to 240d and the insulators 241a to 241d described in Embodiment 1, respectively.

[0398] In addition, a capacitor 140 is disposed on the insulator 285. The capacitor 140 includes a conductive layer 141, a conductive layer 145, and an insulating layer 143 located therebetween. The conductive layer 141 serves as one electrode of the capacitor 140, the conductive layer 145 serves as the other electrode of the capacitor 140, and the insulating layer 143 serves as the dielectric of the capacitor 140.

[0399] A conductive layer 141 is disposed on an insulator 285 and embedded in an insulating layer 154. The conductive layer 141 is electrically connected to a conductor 242a of a transistor 520 via a conductor 240. An insulating layer 143 is disposed covering the conductive layer 141. A conductive layer 145 is disposed in the region where it overlaps with the conductive layer 141, separated by the insulating layer 143.

[0400] Capacitor 140 corresponds to Figure 8A The capacitor 400 is shown in the figure. Although in Figure 17 The capacitor 140 is simplified, but it can also be used. Figure 8A The capacitor 400 and its surrounding structure as described above. For example, such as... Figure 8A As shown, an insulator that blocks impurities such as hydrogen can be provided in a manner that covers the capacitor. This prevents hydrogen contained in and near the light-emitting element from diffusing into the underlying transistor 520. Therefore, a display device with high reliability can be provided.

[0401] In addition, such as Figure 8A As shown, a wiring layer may also be provided on the capacitor 140. Furthermore, the connection relationships of circuit elements, wiring, vias, etc., in the display device according to this embodiment are not limited to... Figure 17 The connection relationships are shown. The connection relationships of circuit components, wiring, vias, etc., can be appropriately set according to the pixel circuit of the display device. The capacitor 140 is provided with an insulating layer 155a, an insulating layer 155b is provided on the insulating layer 155a, and an insulating layer 155c is provided on the insulating layer 155b.

[0403] Inorganic insulating films can be appropriately used for insulating layers 155a, 155b, and 155c. For example, it is preferable to use silicon oxide films as insulating layers 155a and 155c, and silicon nitride films as insulating layer 155b. Thus, insulating layer 155b can be used as an etching protective film. Although an example is shown in this embodiment where a portion of insulating layer 155c is etched to form a recess, it is also possible not to provide a recess in insulating layer 155c.

[0404] Light-emitting elements 110R, 110G and 110B are disposed on the insulating layer 155c.

[0405] Light-emitting element 110R includes a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. Light-emitting element 110G includes a pixel electrode 111G, an organic layer 112G, a common layer 114, and a common electrode 113. Light-emitting element 110B includes a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The common layer 114 and the common electrode 113 are jointly disposed in light-emitting elements 110R, 110G, and 110B.

[0406] The organic layer 112R included in the light-emitting element 110R contains a light-emitting organic compound that emits at least red light. The organic layer 112G included in the light-emitting element 110G contains a light-emitting organic compound that emits at least green light. The organic layer 112B included in the light-emitting element 110B contains a light-emitting organic compound that emits at least blue light. Organic layers 112R, 112G, and 112B may each be referred to as EL layers, and each includes at least a layer (light-emitting layer) containing a light-emitting organic compound.

[0407] The display device 500A forms light-emitting devices separately for each light-emitting color, resulting in minimal chromaticity variation between low-brightness and high-brightness light emission. Furthermore, the organic layers 112R, 112G, and 112B are separated from each other, thus suppressing crosstalk between adjacent sub-pixels even when using a high-definition display panel. Therefore, a high-definition display panel with high display quality can be achieved. An insulating layer 125, a resin layer 126, and a layer 128 are provided in the area between adjacent light-emitting elements.

[0409] The pixel electrodes 111R, 111G, and 111B of the light-emitting element are electrically connected to the conductor 242a of the transistor 520 via a plug 156 embedded in insulating layers 155a, 155b, and 155c, a conductive layer 141 embedded in insulating layer 154, and a conductor 240. The height of the top surface of insulating layer 155c is the same as or approximately the same as the height of the top surface of plug 156. Various conductive materials can be used as the plug.

[0410] In addition, a protective layer 121 is provided on the light-emitting elements 110R, 110G and 110B. A substrate 170 is attached to the protective layer 121 by an adhesive layer 171.

[0411] No insulating layer covering the top surface of the pixel electrode 111 is provided between two adjacent pixel electrodes 111. Therefore, the spacing between adjacent light-emitting elements can be very small. Thus, a high-definition or high-resolution display device can be realized.

[0412] [Display Device 500B] The following describes display devices whose structures differ from those described above. Note that parts identical to those described above are referred to in the above description, and sometimes the description is omitted.

[0413] Figure 18 The display device 500B shown has a structure in which transistor 520A on substrate 201 and transistor 520B on transistor 520A are stacked. Here, transistors 520A and 520B have the same structure as transistor 520. In other words, the display device 500B has a structure in which transistor 520A and transistor 520B are stacked on substrate 201. Figure 17 The display device 500A shown has a structure in which an additional layer including transistor 520 is added between the layer including transistor 520 and the substrate 201.

[0414] Similar to display device 500A, various transistors shown in Embodiment 1 can be used as transistors 520A and 520B. For example, in the layer including transistor 520A and the layer including transistor 520B, such as Figure 3A As shown, insulators that block impurities such as hydrogen can be provided on the upper and lower layers of the transistor. This prevents hydrogen contained in and near the substrate and the light-emitting element from diffusing into transistors 520A and 520B. Furthermore, by providing insulator 241 to cover the sides of conductor 240, hydrogen contained in and near the light-emitting element can be prevented from diffusing through conductor 240 to insulator 280. Thus, a display device with high reliability can be provided.

[0415] In addition, although Figure 18 Simplified, but as Figure 8A As shown with conductors 412, 240c, 218, and 217, transistors 520A and 520B can be electrically connected by connecting wiring to vias. Furthermore, the connection relationships of circuit elements, wiring, vias, etc., in the display device according to this embodiment are not limited to... Figure 18 The connection relationships are shown. The connection relationships of circuit components, wiring, vias, etc., can be appropriately set according to the pixel circuit of the display device.

[0416] [Display Device 500C] Figure 19 The display device 500C shown has a structure in which transistors 310 with channels formed in a semiconductor substrate and transistors 520B on transistors 310 are stacked. Here, transistor 520B has the same structure as transistor 520. In other words, the display device 500C has a structure in which... Figure 18 The display device 500B shown has a structure in which a layer including transistor 310 is provided instead of a layer including transistor 520A.

[0417] Transistor 310 is a transistor having a channel formation region in substrate 311. Substrate 311 can be, for example, a semiconductor substrate such as a single-crystal silicon substrate. Transistor 310 includes a portion of substrate 311, a conductor 316, a low-resistance region 314, an insulator 315, and an insulator 317. Conductor 316 serves as the gate electrode. Insulator 315 is located between substrate 311 and conductor 316 and serves as the gate insulating layer. Low-resistance region 314 is a region in substrate 311 doped with impurities and serves as one of the source and drain electrodes. Insulator 317 covers the sides of conductor 316.

[0418] In addition, a component separation layer 318 is provided between two adjacent transistors 310 in a manner embedded in the substrate 311.

[0419] Similar to the display device 500A, various transistors shown in Embodiment 1 can be used as transistor 520B. For example, in the layer including transistor 520B, such as Figure 3A As shown, insulators that block impurities such as hydrogen can be provided on the upper and lower layers of the transistor. This prevents hydrogen contained in and near the light-emitting element from diffusing into the transistor 520B. Furthermore, it prevents hydrogen contained in and near the transistor 310 from diffusing into the transistor 520B. Moreover, by providing insulator 241 to cover the sides of conductor 240, it prevents hydrogen contained in and near the light-emitting element from diffusing through conductor 240 to insulator 280. Thus, a display device with high reliability can be provided.

[0420] In addition, although Figure 19 Simplified, but as Figure 8A As shown with conductors 412, 240c, 218, and 217, transistor 520B can be electrically connected to transistor 310 by connecting wiring to vias. Here, as Figure 4A As shown, by providing a conductor 218c containing tantalum nitride as conductor 218, impurities such as hydrogen and copper can be prevented from diffusing to transistor 520B through the wiring and vias connected to transistor 310. This provides a display device with high reliability. Furthermore, the connection relationships of circuit elements, wiring, vias, etc., in the display device according to this embodiment are not limited to... Figure 18 The connection relationships are shown. The connection relationships of circuit components, wiring, vias, etc., can be appropriately set according to the pixel circuit of the display device.

[0421] At least a portion of this embodiment can be implemented in combination with other embodiments or examples described in this specification.

[0422] (Implementation Method 3) In this embodiment, an example of the structure of a display device that can be used in a display device manufactured using a transistor according to one aspect of the present invention will be described. The display device shown below can be used in the pixel unit 584, etc., of Embodiment 2 described above. One aspect of the present invention is a display device including light-emitting elements (also called light-emitting devices). The display device includes two or more pixels that emit different colors. Each pixel includes a light-emitting element. Each light-emitting element includes a pair of electrodes and an EL layer therebetween. The light-emitting elements are preferably organic EL elements (organic electroluminescent elements). Two or more light-emitting elements emitting different colors each include an EL layer comprising different materials. For example, a full-color display device can be realized by including three light-emitting elements that respectively emit red (R), green (G), or blue (B) light.

[0424] When manufacturing a display device comprising multiple light-emitting elements with different emitting colors, it is necessary to form at least one layer containing light-emitting material (light-emitting layer) into island shapes. Here, it is known to form island-shaped organic films using a shadow mask, such as a metal mask, by vapor deposition when forming part or all of the EL layer. However, this method suffers from various influences, such as the precision of the metal mask, misalignment between the metal mask and the substrate, metal mask deflection, and enlargement of the deposited film outline due to vapor scattering, resulting in deviations between the shape and position of the island-shaped organic film and the designed shape and position, making it difficult to achieve high resolution and high aperture ratio in the display device. Furthermore, during vapor deposition, the thickness at the ends sometimes decreases due to blurred layer outlines. That is, the thickness of the island-shaped light-emitting layer sometimes varies depending on its position. Moreover, when manufacturing large and high-resolution or high-definition display devices, there are concerns about decreased manufacturing yield due to low dimensional accuracy of the metal mask and deformation caused by heat. Therefore, measures have been taken to simulate increased resolution (also known as pixel density) by employing special pixel arrangements such as Pentile arrays.

[0425] Note that in this specification, etc., "island-like" refers to the state in which two or more layers made of the same material are physically separated in the same process. For example, an island-like light-emitting layer refers to a light-emitting layer that is physically separated from its adjacent light-emitting layers.

[0426] In one aspect of the present invention, the EL layer is processed into a fine pattern using photolithography instead of a shadow mask such as an FMM (Fine Metal Mask). Therefore, a display device with high resolution and high aperture ratio, which is currently difficult to achieve, can be realized. Furthermore, since the EL layer can be manufactured separately, a display device with very vivid and high contrast can be realized. Alternatively, for example, both a metal mask and photolithography can be used to process the EL layer into a fine pattern.

[0427] Furthermore, part or all of the EL layer can be physically separated. This suppresses leakage current between light-emitting elements via a layer shared by adjacent light-emitting elements (also known as a common layer). Therefore, unintended light emission due to crosstalk can be suppressed, enabling display devices with very high contrast. In particular, display devices with high current efficiency at low brightness can be achieved.

[0428] One aspect of the present invention can also realize a display device that combines a white light-emitting element and a color filter. In this case, light-emitting elements with the same structure can be used as individual light-emitting elements in pixels (sub-pixels) that emit light of different colors, and all layers in each light-emitting element can be used as a common layer. Furthermore, some or all of each EL layer can be cut using photolithography. As a result, a display device with high contrast can be realized by suppressing leakage current through the common layer. In particular, in a device having a series structure of multiple light-emitting layers stacked with a highly conductive intermediate layer, leakage current through the intermediate layer can be effectively prevented, thus realizing a display device that combines high brightness, high definition, and high contrast.

[0429] When processing the EL layer using photolithography, degradation can sometimes occur due to partial exposure of the light-emitting layer. Therefore, it is preferable to provide an insulating layer that at least covers the sides of the island-shaped light-emitting layer. This insulating layer may also cover a portion of the top surface of the island-shaped EL layer. This insulating layer is preferably made of a material that blocks water and oxygen. For example, an inorganic insulating film that does not readily allow water or oxygen to diffuse can be used. This suppresses degradation of the EL layer, resulting in a highly reliable display device.

[0430] Furthermore, there is a region (recess) between two adjacent light-emitting elements where the EL layer of each light-emitting element is not disposed. When a common electrode or a common electrode and a common layer are formed to cover this recess, the common electrode sometimes breaks off due to a step at the end of the EL layer (also called a break), resulting in the common electrode on the EL layer being insulated. Therefore, it is preferable to use a structure that fills the localized step between two adjacent light-emitting elements with a resin layer serving as a planarization film (also called LFP: Local Filling Planarization). This resin layer serves as a planarization film. This suppresses the breakage of the common layer or common electrode, resulting in a highly reliable display device.

[0431] Hereinafter, a more specific structural example of a display device according to one aspect of the present invention will be described with reference to the accompanying drawings.

[0432] [Structure Example 1] Figure 20AThis diagram illustrates a top view of a display device 100 according to one embodiment of the present invention. The display device 100 includes, on a substrate 101, a plurality of red-emitting elements 110R, a plurality of green-emitting elements 110G, and a plurality of blue-emitting elements 110B. Figure 20A To facilitate the differentiation of each light-emitting element, the symbols “R”, “G”, and “B” are attached to the light-emitting area of ​​each element.

[0433] The light-emitting elements 110R, 110G and 110B are all arranged in a matrix. Figure 20A This illustrates a so-called stripe arrangement where light-emitting elements of the same color are arranged in one direction. Note that the arrangement of light-emitting elements is not limited to this; other arrangements such as S-stripes, Delta, Bayer, and zigzag can also be used, as well as Pentile and Diamond arrangements.

[0434] As light-emitting elements 110R, 110G, and 110B, OLEDs (Organic Light Emitting Diodes) or QLEDs (Quantum-dot Light Emitting Diodes) are preferably used, for example. Examples of light-emitting materials included in the EL element include fluorescent materials, phosphorescent materials, and materials exhibiting thermally activated delayed fluorescence (TADF) materials. In addition to organic compounds, inorganic compounds (quantum dot materials, etc.) can also be used as light-emitting materials in the EL element.

[0435] also, Figure 20A A connection electrode 111C is shown that is electrically connected to the common electrode 113. The connection electrode 111C is supplied with a potential (e.g., anode potential or cathode potential) for supplying the common electrode 113. The connection electrode 111C is disposed outside the display area where the light-emitting elements 110R, etc., are arranged.

[0436] The connecting electrode 111C can be disposed along the outer periphery of the display area. For example, it can be disposed along one edge of the outer periphery of the display area, or it can be disposed along two or more edges of the outer periphery of the display area. That is, when the top surface of the display area is rectangular, the top surface shape of the connecting electrode 111C can be strip-shaped (rectangular), L-shaped, "gate"-shaped (square bracket-shaped), or square, etc.

[0437] Figure 20B , Figure 20C They correspond to Figure 20A A cross-sectional diagram of the dashed lines A1-A2 and A3-A4 in the diagram. Figure 20B A cross-sectional schematic diagram of light-emitting elements 110R, 110G, and 110B is shown. Figure 20C A cross-sectional schematic diagram of the connection portion 130 connecting the connecting electrode 111C and the common electrode 113 is shown.

[0438] Light-emitting element 110R includes a pixel electrode 111R, an organic layer 112R, a common layer 114, and a common electrode 113. Light-emitting element 110G includes a pixel electrode 111G, an organic layer 112G, a common layer 114, and a common electrode 113. Light-emitting element 110B includes a pixel electrode 111B, an organic layer 112B, a common layer 114, and a common electrode 113. The common layer 114 and the common electrode 113 are jointly disposed in light-emitting elements 110R, 110G, and 110B.

[0439] The organic layer 112R included in the light-emitting element 110R contains a light-emitting organic compound that emits at least red light. The organic layer 112G included in the light-emitting element 110G contains a light-emitting organic compound that emits at least green light. The organic layer 112B included in the light-emitting element 110B contains a light-emitting organic compound that emits at least blue light. Organic layers 112R, 112G, and 112B may each be referred to as EL layers, and each includes at least a layer (light-emitting layer) containing a light-emitting organic compound.

[0440] Hereinafter, when describing the common elements among light-emitting elements 110R, 110G, and 110B, they will sometimes be referred to as light-emitting element 110. Similarly, when describing the common elements among components such as organic layers 112R, 112G, and 112B, which are distinguished by letters, symbols with omitted letters will sometimes be used.

[0441] The organic layer 112 and the common layer 114 may each independently include one or more of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. For example, the organic layer 112 has a stacked structure of a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer stacked from the pixel electrode 111 side, and the common layer 114 includes an electron injection layer.

[0442] Pixel electrodes 111R, 111G, and 111B are all disposed in each light-emitting element. Furthermore, a common electrode 113 and a common layer 114 are provided as a single layer shared by all light-emitting elements. One of the pixel electrodes and the common electrode 113 uses a conductive film that is transparent to visible light, while the other uses a reflective conductive film. By making each pixel electrode transparent and the common electrode 113 reflective, a bottom-emitting type (bottom-emitting structure) display device can be realized; conversely, by making each pixel electrode reflective and the common electrode 113 transparent, a top-emitting type (top-emitting structure) display device can be realized. Furthermore, by making both the pixel electrode and the common electrode 113 transparent, a double-sided emitting type (double-sided emitting structure) display device can also be realized.

[0443] A protective layer 121 is provided on the common electrode 113 in such a way as to cover the light-emitting element 110. The protective layer 121 has the function of preventing impurities such as water from diffusing from above to each light-emitting element.

[0444] The end of the pixel electrode 111 preferably has a tapered shape. When the end of the pixel electrode 111 has a tapered shape, the organic layer 112 disposed along the end of the pixel electrode 111 can also have a tapered shape. By making the end of the pixel electrode 111 tapered, the coverage of the organic layer 112 disposed across the end of the pixel electrode 111 can be improved. Furthermore, by making the side of the pixel electrode 111 tapered, foreign matter (e.g., dust or particles) from the manufacturing process can be easily removed by washing or other processes, which is therefore preferred.

[0445] The organic layer 112 is processed into an island shape using photolithography. Therefore, the organic layer 112 has a shape at its ends where the angle between the top surface and the side surface is close to 90°. On the other hand, the thickness of organic films formed using FMM and the like tends to decrease as they approach the ends. For example, the top surface is formed in a slope shape in the range of 1 μm to 10 μm from the ends, making it difficult to distinguish between the top surface and the side surface.

[0446] An insulating layer 125, a resin layer 126, and a layer 128 are disposed between two adjacent light-emitting elements.

[0447] Between two adjacent light-emitting elements, the sides of each organic layer 112 are separated by a resin layer 126. The resin layer 126 is located between the two adjacent light-emitting elements and is disposed in such a way that it fills the ends of each organic layer 112 and the area between the two organic layers 112. The top surface of the resin layer 126 has a smooth convex shape, and a common layer 114 and a common electrode 113 are disposed to cover the top surface of the resin layer 126.

[0448] The resin layer 126 serves as a planarization film to fill the step between two adjacent light-emitting elements. By providing the resin layer 126, insulation of the common electrode on the organic layer 112 can be prevented due to the phenomenon of the common electrode 113 being interrupted by the step at the end of the organic layer 112 (also known as a break). The resin layer 126 can also be referred to as an LFP (Local Filling Planarization) layer.

[0449] As resin layer 126, an insulating layer containing organic materials can be suitable. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimide amide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, and precursors of the above resins can be used as resin layer 126. Furthermore, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can also be used as resin layer 126.

[0450] Furthermore, a photosensitive resin can be used as the resin layer 126. A photoresist can also be used as the photosensitive resin. The photosensitive resin can be either a positive or negative material.

[0451] The resin layer 126 may also contain a material that absorbs visible light. For example, the resin layer 126 itself may be composed of a material that absorbs visible light, and the resin layer 126 may also contain a pigment that absorbs visible light. As the resin layer 126, for example, a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light; or a resin that contains carbon black as a pigment and is used as a black matrix; etc.

[0452] The insulating layer 125 contacts the side surface of the organic layer 112. Furthermore, the insulating layer 125 covers the upper end of the organic layer 112. Additionally, a portion of the insulating layer 125 contacts the top surface of the substrate 101.

[0453] An insulating layer 125 is located between the resin layer 126 and the organic layer 112 and serves as a protective film to prevent the resin layer 126 from contacting the organic layer 112. When the organic layer 112 comes into contact with the resin layer 126, the organic layer 112 may be dissolved due to organic solvents or the like used in forming the resin layer 126. Therefore, by providing an insulating layer 125 between the organic layer 112 and the resin layer 126, the sides of the organic layer 112 can be protected.

[0454] The insulating layer 125 can be an insulating layer containing inorganic materials. Inorganic insulating films such as oxide insulating films, nitride insulating films, oxynitride insulating films, and oxynitride insulating films can be used as the insulating layer 125. The insulating layer 125 can be a single-layer structure or a multilayer structure. Examples of oxide insulating films include silicon oxide films, aluminum oxide films, magnesium oxide films, indium gallium zinc oxide films, gallium oxide films, germanium oxide films, yttrium oxide films, zirconium oxide films, lanthanum oxide films, neodymium oxide films, hafnium oxide films, and tantalum oxide films. Examples of nitride insulating films include silicon nitride films and aluminum nitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films. Examples of oxynitride insulating films include silicon oxynitride films and aluminum oxynitride films. In particular, by using inorganic insulating films such as alumina films, hafnium oxide films, and silicon oxide films formed by the ALD method to form insulating layer 125, an insulating layer 125 with fewer pinholes and excellent protection of the EL layer can be formed.

[0455] In this specification, etc., "oxynitride" refers to a material in which the oxygen content is greater than the nitrogen content in its composition, while "nitrogen oxide" refers to a material in which the nitrogen content is greater than the oxygen content in its composition. For example, when described as "silicon oxynitride", it refers to a material in which the oxygen content is greater than the nitrogen content in its composition, while when described as "silicon oxynitride", it refers to a material in which the nitrogen content is greater than the oxygen content in its composition.

[0456] The insulating layer 125 can be formed using sputtering, CVD, PLD, ALD, or other methods. The insulating layer 125 is preferably formed using the ALD method, which has high coverage.

[0457] Alternatively, a reflective film (e.g., a metal film selected from one or more of silver, palladium, copper, titanium, and aluminum) can be provided between the insulating layer 125 and the resin layer 126 to reflect the light emitted by the light-emitting layer. This can further improve the light extraction efficiency.

[0458] Layer 128 is a residual portion of a protective layer (also called a mask layer or sacrificial layer) used to protect the organic layer 112 during etching. Layer 128 can use a material that can also be used for the aforementioned insulating layer 125. In particular, it is preferable that both layer 128 and insulating layer 125 are made of the same material, thereby allowing the use of the same processing equipment, etc.

[0459] In particular, inorganic insulating films such as alumina films, hafnium oxide films, and silicon oxide films formed by the ALD method have fewer pinholes, thus providing excellent protection for the EL layer. Therefore, they are suitable for use in insulating layers 125 and 128.

[0460] The protective layer 121 may, for example, have a single-layer structure or a multilayer structure comprising at least an inorganic insulating film. Examples of inorganic insulating films include oxide films or nitride films such as silicon oxide films, silicon oxynitride films, silicon oxynitride films, silicon nitride films, aluminum oxide films, aluminum oxynitride films, and hafnium oxide films. Alternatively, semiconductor or conductive materials such as indium gallium oxide, indium zinc oxide, indium tin oxide, and indium gallium zinc oxide may be used as the protective layer 121.

[0461] The protective layer 121 can also be a laminate of an inorganic insulating film and an organic insulating film. For example, it is preferable to sandwich an organic insulating film between a pair of inorganic insulating films. Furthermore, the organic insulating film is preferably used as a planarization film. Therefore, the top surface of the organic insulating film can be flattened, thus improving the coverage of the inorganic insulating film thereon, thereby improving the barrier properties. In addition, the flattened top surface of the protective layer 121 is preferred because it reduces the influence of the uneven shape of the underlying structure when structures (e.g., color filters, electrodes of touch sensors, or lens arrays, etc.) are placed above the protective layer 121.

[0462] Figure 20C A connection portion 130 is shown, which electrically connects the connecting electrode 111C to the common electrode 113. In the connection portion 130, an opening is provided in the insulating layer 125 and the resin layer 126 on the connecting electrode 111C. The connecting electrode 111C is electrically connected to the common electrode 113 through this opening.

[0463] Notice, Figure 20C The diagram shows a connection portion 130 where the connecting electrode 111C and the common electrode 113 are electrically connected. However, the common electrode 113 can also be disposed on the connecting electrode 111C with a common layer 114 in between. In particular, when a carrier injection layer is used as the common layer 114, the resistivity of the material used for the common layer 114 is sufficiently low and its thickness is also small, so in many cases, it is not a problem for the common layer 114 to be located in the connection portion 130. Therefore, the common electrode 113 and the common layer 114 can be formed using the same masking mask, thus reducing manufacturing costs.

[0464] [Structure Example 2] The following describes a display device whose structure differs from that of Structural Example 1 described above. Note that parts that are the same as those in Structural Example 1 are sometimes omitted from the description with reference to Structural Example 1.

[0465] Figure 21A is a cross-sectional schematic diagram of display device 100a. The main differences between display device 100a and display device 100 are: the structure of the light-emitting element; and the fact that the former includes a coloring layer.

[0466] Display device 100a includes a light-emitting element 110W that emits white light. The light-emitting element 110W includes a pixel electrode 111, an organic layer 112W, a common layer 114, and a common electrode 113. The organic layer 112W emits white light. For example, the organic layer 112W may contain two or more light-emitting materials whose emitted colors are complementary. For example, the organic layer 112W may contain a light-emitting organic compound that emits red light, a light-emitting organic compound that emits green light, and a light-emitting organic compound that emits blue light. Furthermore, it may also contain a light-emitting organic compound that emits blue light and a light-emitting organic compound that emits yellow light.

[0467] Between two adjacent light-emitting elements 110W, each organic layer 112W is separated. This suppresses leakage current flowing through the organic layer 112W between adjacent light-emitting elements 110W, and thus suppresses crosstalk caused by this leakage current. Therefore, a display device with high contrast and color reproduction can be achieved.

[0468] An insulating layer 122 serving as a planarization film is provided on the protective layer 121, and a coloring layer 116R, a coloring layer 116G, and a coloring layer 116B are provided on the insulating layer 122.

[0469] As the insulating layer 122, an organic resin film or an inorganic insulating film with a planarized top surface can be used. Since the insulating layer 122 is the surface on which the coloring layers 116R, 116G, and 116B are formed, a planar top surface of the insulating layer 122 can ensure uniform thickness of the coloring layers 116R, etc., thereby improving color purity. Note that when the thickness of the coloring layers 116R, etc., is uneven, the light absorption varies depending on the region within the coloring layer 116R, which may lead to a decrease in color purity.

[0470] [Structure Example 3] Figure 21B This is a cross-sectional schematic diagram of the display device 100b.

[0471] Light-emitting element 110R includes a pixel electrode 111, a conductive layer 115R, an organic layer 112W, and a common electrode 113. Light-emitting element 110G includes a pixel electrode 111, a conductive layer 115G, an organic layer 112W, and a common electrode 113. Light-emitting element 110B includes a pixel electrode 111, a conductive layer 115B, an organic layer 112W, and a common electrode 113. Conductive layers 115R, 115G, and 115B are all transparent and used as optical adjustment layers.

[0472] By using a film that reflects visible light as the pixel electrode 111 and a film that is both reflective and transmissive to visible light as the common electrode 113, a microcavity resonator (microcavity) structure can be realized. At this point, by adjusting the thicknesses of the conductive layers 115R, 115G, and 115B in a manner that achieves the most suitable optical path length, even using an organic layer 112 that emits white light, enhanced light can be obtained by extracting light of different wavelengths from the light-emitting elements 110R, 110G, and 110B respectively.

[0473] Furthermore, by setting color layers 116R, 116G, and 116B on the optical paths of light-emitting elements 110R, 110G, and 110B respectively, light with high color purity can be extracted.

[0474] In addition, an insulating layer 123 is provided covering the ends of the pixel electrode 111 and the conductive layer 115. The ends of the insulating layer 123 preferably have a tapered shape. By providing the insulating layer 123, the coverage of the organic layer 112W, the common electrode 113, and the protective layer 121 formed thereon can be improved.

[0475] The organic layer 112W and the common electrode 113 are respectively disposed as a continuous film in each light-emitting element. By adopting this structure, the manufacturing process of the display device can be greatly simplified, so it is preferred.

[0476] Here, the end of the pixel electrode 111 preferably has an almost vertical shape. This allows for the formation of a steeply sloping portion on the surface of the insulating layer 123, while a thin portion can be formed on a part of the organic layer 112W covering that portion, or a portion of the organic layer 112W can be separated. This allows for the suppression of leakage current between adjacent light-emitting elements generated through the organic layer 112W without processing the organic layer 112W using photolithography or similar methods.

[0477] The above illustrates an example of the structure of a display device.

[0478] At least a portion of this embodiment can be implemented in combination with other embodiments or examples described in this specification.

[0479] (Implementation Method 4) In this embodiment, an example of the structure of a pixel circuit of a display device that can be used in one aspect of the present invention is described. Figure 22A and Figure 22B An example of the structure of pixel circuit 51 and light-emitting device 61 connected to pixel circuit 51 are shown. Figure 22A It is a diagram showing the connections of the various components. Figure 22BThis is a schematic diagram illustrating the vertical relationship between layer 62, which includes driving circuitry; layer 83, which includes multiple transistors in pixel circuitry; and layer 81, which includes light-emitting devices. For example, in... Figure 19 In the display device 500C shown, layer 62 corresponds to the layer including transistor 310, layer 83 corresponds to the layer including transistor 520B and capacitor 140, and layer 81 corresponds to the layer including light-emitting elements 110R, 110G and 110B.

[0481] exist Figure 22A and Figure 22B The pixel circuit 51 shown as an example includes transistors 52A, 52B, 52C, and capacitor 53. Transistors 52A, 52B, and 52C can be constructed using OS transistors. Each OS transistor of transistors 52A, 52B, and 52C preferably includes a back gate electrode, in which case it can have a structure that supplies the same signal to the back gate electrode as the gate electrode or a structure that supplies a different signal to the back gate electrode than the gate electrode.

[0482] Transistor 52B includes a gate electrode electrically connected to transistor 52A, a first electrode electrically connected to light-emitting device 61, and a second electrode electrically connected to wiring ANO. Wiring ANO is a wiring used to supply potential, which is used to provide current to light-emitting device 61. Transistor 52B has the function of controlling the amount of current flowing through light-emitting device 61. That is, transistor 52B has the function of controlling the amount of light emitted by light-emitting device 61. Therefore, transistor 52B can be called a "driving transistor".

[0483] Transistor 52A includes a first electrode electrically connected to the gate electrode of transistor 52B, a second electrode electrically connected to wiring SL which is used as a source line, and a gate electrode having the function of controlling an on state or a non-on state according to the potential of wiring GL1 which is used as a gate line.

[0484] Transistor 52C includes a first electrode electrically connected to wiring V0, a ​​second electrode electrically connected to light-emitting device 61, and a gate electrode that functions to control an on or off state based on the potential of wiring GL2, which serves as a gate line. Wiring V0 is used to supply a reference potential and is used to output the current flowing through pixel circuit 51 to driving circuit 65 or functional circuits formed in layer 62.

[0485] The capacitor 53 includes a conductive film electrically connected to the gate electrode of the transistor 52B and a conductive film electrically connected to the second electrode of the transistor 52C.

[0486] The light-emitting device 61 includes an anode electrically connected to the first electrode of the transistor 52B and a cathode electrically connected to the wiring VCOM. The wiring VCOM is a wiring used to supply a potential that is used to provide current to the light-emitting device 61.

[0487] Therefore, the intensity of light emitted by the light-emitting device 61 can be controlled based on the image signal supplied to the gate electrode of transistor 52B. Furthermore, the non-uniformity of the gate-source voltage of transistor 52B can be suppressed based on the reference potential of the wiring V0 supplied through transistor 52C.

[0488] Furthermore, a current value that can be used to set pixel parameters can be output from wiring V0. More specifically, wiring V0 can be used as a monitoring line to output the current flowing through transistor 52B or the current flowing through light-emitting device 61 to the outside. The current output to wiring V0 is converted into a voltage by a source follower circuit or the like and output to the outside. Alternatively, it can be converted into a digital signal by an A / D converter or the like and output to functional circuits formed in layer 62.

[0489] In one embodiment of the present invention, the light-emitting device refers to a self-emissive display element such as an organic EL element (also known as an OLED (Organic Light Emitting Diode)). Alternatively, the light-emitting device electrically connected to the pixel circuit can be a self-emissive light-emitting device such as an LED (Light Emitting Diode), a micro LED, a QLED (Quantum-dot Light Emitting Diode), or a semiconductor laser.

[0490] exist Figure 22B In the illustrated structure, the wiring connecting the pixel circuit 51 and the driving circuit 65 can be shortened, thus reducing the wiring resistance. Therefore, data writing can be performed at high speed, allowing the display device to be driven at high speed. Consequently, even with an increase in the number of pixel circuits 51 in the display device, a sufficient frame period can be ensured, increasing the pixel density of the display device. Furthermore, by increasing the pixel density of the display device, the clarity of the image displayed on the display device can be improved. For example, the pixel density of the display device can be 1000 ppi or more, 5000 ppi or more, or 7000 ppi or more. Therefore, the display device according to this embodiment can be, for example, an AR or VR display device, and can be appropriately used in electronic devices such as HMDs where the display unit is close to the user.

[0491] Notice, Figure 22A and Figure 22BAn example of a pixel circuit 51 comprising three transistors is shown, but the invention is not limited to this. The following describes examples of pixel circuit structures and driving methods that can be used in pixel circuit 51.

[0492] Figure 23A The pixel circuit 51A shown includes transistor 52A, transistor 52B, and capacitor 53. Additionally, Figure 23A A light-emitting device 61 connected to pixel circuit 51A is shown. Additionally, pixel circuit 51A is electrically connected to wiring SL, wiring GL, wiring ANO, and wiring VCOM. Pixel circuit 51A has... Figure 22A The pixel circuit 51 shown has transistor 52C removed and wiring GL1 and wiring GL2 replaced with wiring GL.

[0493] In transistor 52A, the gate is electrically connected to wiring GL, one of the source and drain is electrically connected to wiring SL, and the other is electrically connected to the gate of transistor 52B and one electrode of capacitor 53. In transistor 52B, one of the source and drain is electrically connected to wiring ANO, and the other is electrically connected to the anode of light-emitting device 61. The other electrode of capacitor 53 is electrically connected to the anode of light-emitting device 61. The cathode of light-emitting device 61 is electrically connected to wiring VCOM.

[0494] Figure 23B The pixel circuit 51B shown is a structure in which a transistor 52C is added to the pixel circuit 51A. Furthermore, the pixel circuit 51B is electrically connected to wiring V0.

[0495] Figure 23C The pixel circuit 51C shown is an example where transistors 52A and 52B of the aforementioned pixel circuit 51A are a pair of transistors with their gates electrically connected to each other. Furthermore, Figure 23D The pixel circuit 51D shown is an example of using this transistor in the pixel circuit 51B. Therefore, the current that the transistor can carry can be increased. Note that all transistors shown here use a pair of gates electrically connected, but this is not a limitation. Alternatively, transistors including a pair of gates, each electrically connected to a different wiring, can also be used. For example, by using a transistor where one gate is electrically connected to the source, reliability can be improved.

[0496] Figure 24A The pixel circuit 51E shown has a structure that adds a transistor 52D to the pixel circuit 51B described above. Furthermore, the pixel circuit 51E is electrically connected to wirings GL1, GL2, and GL3, which are used as gate lines. Note that in this embodiment and the like, wirings GL1, GL2, and GL3 are sometimes collectively referred to as wiring GL. Therefore, wiring GL is not limited to one, and sometimes there are multiple wirings.

[0497] In transistor 52D, the gate is electrically connected to wiring GL3, and one of the source and drain is electrically connected to the gate of transistor 52B, while the other is electrically connected to wiring V0. Additionally, the gate of transistor 52A is electrically connected to wiring GL1, and the gate of transistor 52C is electrically connected to wiring GL2.

[0498] By simultaneously turning on transistors 52C and 52D, the source and gate of transistor 52B become at the same potential, thus allowing transistor 52B to be in a non-conducting state. This forcibly blocks the current flowing through the light-emitting device 61. This pixel circuit is preferred when using a display method that alternately sets the display period and the light-off period.

[0499] Figure 24B The pixel circuit 51F shown is an example of pixel circuit 51E with capacitor 53A added. Capacitor 53A is used as a holding capacitor.

[0500] Figure 24C The pixel circuit 51G shown is Figure 24D The pixel circuits 51H shown are examples of pixel circuits 51E and 51F described above, using transistors including a pair of gates. Transistors 52A, 52C, and 52D are transistors whose gates are electrically connected to each other, and transistor 52B is a transistor whose gate is electrically connected to its source.

[0501] Figure 25 The pixel circuit 51J shown includes transistors 56A to 56G and capacitors 57A to 57C. It can be considered that transistors 56A, 56B, 56C, and capacitor 57A of the pixel circuit 51J correspond to... Figure 22A The pixel circuit 51 shown includes transistors 52A, 52B, 56C, and capacitor 53. Note that... Figure 25 Examples are shown where the gates and back gates of transistors 56A, 56C, 56D, 56E, 56F, and 56G are electrically connected. However, it is also possible to supply any potential to the back gate without electrically connecting the gates and back gates. Furthermore, the potential supplied to the back gate is not limited to a fixed potential. The potential supplied to the back gates of the transistors constituting pixel circuit 51J can be different or the same for each transistor. Moreover, it is not necessary to provide a back gate in all transistors constituting pixel circuit 51J. Pixel circuit 51J may also include transistors with back gates and transistors without back gates.

[0502] In transistor 56A, the gate is electrically connected to wiring GL1, the first electrode is electrically connected to wiring SL, and the second electrode is electrically connected to the gate of transistor 56B. In transistor 56B, the first electrode is electrically connected to wiring ANO, and the second electrode is electrically connected to the first electrode of transistor 56F. In transistor 56C, the gate is electrically connected to wiring GL1, the first electrode is electrically connected to the second electrode of transistor 56B, and the second electrode is electrically connected to wiring V0. In transistor 56D, the gate is electrically connected to wiring GL2, the first electrode is electrically connected to the gate of transistor 56B, and the second electrode is electrically connected to the second electrode of transistor 56B. In transistor 56E, the gate is electrically connected to wiring GL2, the first electrode is electrically connected to wiring V1, and the second electrode is electrically connected to the back gate of transistor 56B. In transistor 56F, the gate is electrically connected to the first electrode of transistor 56G, and the second electrode is electrically connected to the anode of the light-emitting device 61. In transistor 56G, the gate is electrically connected to wiring GL1, and the second electrode is electrically connected to wiring GL2. Capacitor 57A is formed between the gate and the second electrode of transistor 56B. Capacitor 57B is formed between the back gate and the second electrode of transistor 56B. Capacitor 57C is formed between the gate and the second electrode of transistor 56F. The cathode of light-emitting device 61 is electrically connected to wiring VCOM. Wiring V1 is a wiring that supplies potential to the back gate of transistor 56B. The charge corresponding to image data held in capacitors 57A and 57B has a significant impact on display quality, so the influence of external noise is preferably minimal. By increasing the capacitance of capacitors 57A and 57B, the influence of external noise can be reduced, thereby enabling a display device with high display quality. Furthermore, capacitor 57A preferably holds the charge corresponding to image data for a period longer than one frame period. Similarly, capacitor 57B preferably holds the charge corresponding to image data for a period longer than one frame period, more preferably for more than one second, further preferably for more than one minute, and even more preferably for more than one hour. Therefore, the capacitance of capacitor 57B can also be greater than the capacitance of capacitor 57A. On the other hand, capacitor 57C only needs to maintain a voltage sufficient to fully turn on transistor 56F, so the capacitance of capacitor 57C can also be smaller than that of capacitors 57A and 57B.

[0504] Furthermore, by using an OS transistor in the pixel circuit 51J, the charge corresponding to the image data in capacitors 57A and 57B can be maintained for an extended period. For example, when displaying a static image that does not require rewriting on a per-frame basis, the image can continue to be displayed even if the operation of the nearby drive circuit is stopped. The aforementioned driving method of stopping the operation of the nearby drive circuit when displaying a static image is also known as "idle stop driving." By performing idle stop driving, the power consumption of the display device can be reduced.

[0505] Alternatively, multi-channel transistors can be used in the pixel circuit described above. A multi-channel transistor includes multiple electrically connected gates and has multiple regions between the source and drain where a semiconductor layer overlaps with the gates. In other words, a multi-channel transistor includes multiple electrically connected gates and has multiple channel forming regions between the source and drain. Furthermore, a transistor can be considered a multi-channel transistor if multiple single-gate transistors are connected in series and their gates are connected.

[0506] For example, when driving transistors or the like operate in the saturation region, the channel length of the transistor is sometimes made longer in order to improve the electrical characteristics in the saturation region. Multi-gate transistors can also be used as transistors with long channel lengths. At least a portion of this embodiment can be implemented in combination with other embodiments or examples described in this specification.

[0508] (Implementation Method 5) In this embodiment, using Figures 26A to 28G An electronic device according to one aspect of the present invention will be described.

[0509] The electronic device of this embodiment includes a display panel (display device) using a transistor according to one aspect of the present invention in its display section. The display device according to one aspect of the present invention easily achieves high definition and high resolution, and furthermore, can achieve high display quality. Therefore, it can be used in the display section of various electronic devices.

[0510] As electronic devices, in addition to large-screen electronic devices such as television sets, desktop or laptop personal computers, monitors for computers, digital signage, and large game machines such as pinball machines, other examples include digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, and sound reproduction devices.

[0511] In particular, because the display panel of one aspect of the present invention can improve clarity, it can be suitably used in electronic devices that include a relatively small display section. Examples of such electronic devices include watch-type and bracelet-type information terminal devices (wearable devices), wearable devices that can be worn on the head, VR devices such as head-mounted displays, AR devices such as glasses, and MR devices.

[0512] The display panel of one embodiment of the present invention preferably has extremely high resolutions such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), 8K (7680×4320 pixels), etc. In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (clarity) of the display panel of one embodiment of the present invention is preferably 100 ppi or higher, preferably 300 ppi or higher, more preferably 500 ppi or higher, further preferably 1000 ppi or higher, even more preferably 2000 ppi or higher, even more preferably 3000 ppi or higher, still more preferably 5000 ppi or higher, and even more preferably 7000 ppi or higher. By using the aforementioned display panel with one or both of high resolution and high definition, the sense of realism and depth can be further enhanced. Furthermore, there are no particular limitations on the screen ratio (aspect ratio) of the display panel according to one aspect of the present invention. For example, the display panel can accommodate various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0513] The electronic device in this embodiment may also include a sensor (which has the function of sensing, detecting, and measuring factors such as force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation).

[0514] The electronic device of this embodiment can have various functions. For example, it can have the following functions: displaying various information (static images, dynamic images, text images, etc.) on the display unit; touch panel function; displaying calendar, date, or time, etc.; executing various software (programs); wireless communication function; reading programs or data stored in the storage medium; etc.

[0515] use Figures 26A to 26D This section describes an example of a wearable device that can be worn on the head. These wearable devices have the capability to display either AR (Augmented Reality) content or VR (Virtual Reality) content. Furthermore, these wearable devices may also have the capability to display SR (Simultaneous Reality) or MR (Mortal Reality) content in addition to AR and VR. When an electronic device has the capability to display content of at least one of AR, VR, SR, and MR, the user's sense of immersion can be enhanced.

[0516] Figure 26A The electronic device 700A shown and Figure 26BThe electronic devices 700B shown include a pair of display panels 751, a pair of frames 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical components 753, a frame 757, and a pair of nose pads 758.

[0517] The display panel 751 can be an embodiment of the display panel of the present invention. Therefore, an electronic device capable of displaying with extremely high clarity can be realized.

[0518] Both electronic devices 700A and 700B can project images displayed on the display panel 751 onto the display area 756 in the optical component 753. Because the optical component 753 is transparent, the user can see the image displayed on the display area by superimposing it with the image seen through the optical component 753. Therefore, both electronic devices 700A and 700B are capable of AR display.

[0519] Both electronic devices 700A and 700B can be equipped with cameras capable of capturing images of the front as imaging units. Furthermore, by incorporating accelerometers such as gyroscopes into both electronic devices 700A and 700B, the orientation of the user's head can be detected, and an image corresponding to that orientation can be displayed on the display area 756.

[0520] The communications section includes a wireless communication device through which image signals can be supplied. Furthermore, in addition to or in addition to the wireless communication device, a connector capable of connecting cables supplying image signals and power potential may also be included.

[0521] In addition, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly or via wired means, or both.

[0522] The frame 721 may also be equipped with a touch sensor module. The touch sensor module has the function of detecting whether the outer surface of the frame 721 is touched. Through the touch sensor module, various processes can be performed by detecting user tap or swipe operations. For example, a tap operation can perform processing such as temporarily pausing or replaying a moving image, and a swipe operation can perform processing such as fast forward or rewind. Furthermore, by providing a touch sensor module in each of the two frames 721, the operating range can be expanded. Various touch sensors can be used as touch sensor modules. For example, capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, and optical sensors can be employed. In particular, capacitive or optical sensors are preferred for use in touch sensor modules.

[0524] When using optical touch sensors, photoelectric conversion devices (also known as photoelectric conversion elements) can be used as light-receiving devices (also known as light-receiving elements). One or both of inorganic semiconductors and organic semiconductors can be used in the active layer of the photoelectric conversion device.

[0525] Figure 26C The electronic device 800A shown is Figure 26D The electronic devices 800B shown include a pair of display units 820, a frame 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0526] The display unit 820 can utilize a display panel according to one aspect of the present invention. Therefore, an electronic device capable of displaying extremely high clarity can be realized. This allows the user to experience a highly immersive experience.

[0527] The display unit 820 is located inside the housing 821 in a position visible through the lens 832. Furthermore, by displaying different images on each of the pair of display units 820, three-dimensional display utilizing parallax can be achieved.

[0528] Both electronic devices 800A and 800B can be referred to as VR-oriented electronic devices. Users who have installed electronic devices 800A or 800B can see the image displayed on the display unit 820 through the lens 832.

[0529] Electronic devices 800A and 800B preferably have a mechanism in which the left and right positions of the lens 832 and the display unit 820 can be adjusted so that the lens 832 and the display unit 820 are in the most suitable position according to the position of the user's eyes. Furthermore, it is preferable to have a mechanism in which the focus is adjusted by changing the distance between the lens 832 and the display unit 820.

[0530] The user can use the mounting unit 823 to attach electronic device 800A or electronic device 800B to their head. Figure 26C Examples of mounting parts 823 are shown, such as those with a temple (also called a temple wire) similar to those of eyeglasses, but they are not limited to this. As long as the user can attach it, the mounting part 823 can have, for example, a helmet-shaped or strap-shaped shape.

[0531] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras can be set to support various viewing angles such as telephoto and wide-angle.

[0532] Note that the example shown here includes an imaging unit 825, which can be a ranging sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object. In other words, the imaging unit 825 is one type of detection unit. For example, an image sensor or a distance image sensor such as LiDAR (Light Detection and Ranging) can be used as the detection unit. By using images acquired by a camera and images acquired by a distance image sensor, more information can be obtained, enabling more precise attitude control.

[0533] The electronic device 800A may also include a vibration mechanism used as a bone conduction headphone. For example, the structure including this vibration mechanism can be adopted as one or more of the display unit 820, the frame 821, and the mounting unit 823. Thus, there is no need to separately install audio equipment such as headphones, earphones, or speakers; one can enjoy images and sound simply by installing the electronic device 800A.

[0534] Electronic devices 800A and 800B may also include input terminals. Cables supplying image signals from image output devices and the like, as well as power for charging batteries installed within the electronic devices, can be connected to the input terminals.

[0535] An electronic device according to one aspect of the present invention may also have the function of wirelessly communicating with the headset 750. The headset 750 includes a communication unit (not shown) and has wireless communication functionality. The headset 750 can receive information (e.g., voice data) from the electronic device via the wireless communication function. For example, Figure 26A The illustrated electronic device 700A has the function of transmitting information to the headset 750 via wireless communication. Furthermore, for example... Figure 26C The electronic device 800A shown has the function of sending information to the headset 750 via wireless communication.

[0536] In addition, electronic devices may also include an earphone unit. Figure 26B The illustrated electronic device 700B includes an earphone unit 727. For example, a structure in which the earphone unit 727 and the control unit are connected by a wire can be adopted. A portion of the wiring connecting the earphone unit 727 and the control unit can also be configured inside the housing 721 or the mounting portion 723.

[0537] same, Figure 26DThe illustrated electronic device 800B includes an earphone unit 827. For example, a structure can be adopted in which the earphone unit 827 and the control unit 824 are connected by a wire. A portion of the wiring connecting the earphone unit 827 and the control unit 824 can also be disposed inside the housing 821 or the mounting portion 823. Furthermore, the earphone unit 827 and the mounting portion 823 can also include magnets. Thus, the earphone unit 827 can be magnetically secured to the mounting portion 823, making storage easy, which is preferable.

[0538] Electronic devices may also include an audio output terminal capable of connecting to headphones or headsets. Furthermore, electronic devices may include one or both of an audio input terminal and an audio input mechanism. As an audio input mechanism, a microphone or similar recording device can be used. By incorporating an audio input mechanism into the electronic device, it can be made to function as a so-called headset.

[0539] Thus, as an embodiment of the present invention, both eyeglass type (electronic device 700A and electronic device 700B, etc.) and goggle type (electronic device 800A and electronic device 800B, etc.) are preferred electronic devices.

[0540] Figure 27A The electronic device 6500 shown is a portable information terminal device that can be used as a smartphone.

[0541] Electronic device 6500 includes a frame 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and a control device 6509. The display unit 6502 has a touch panel function. The control device 6509 includes, for example, one or more selected from a CPU, a GPU, and a storage device. A semiconductor device according to one aspect of the present invention can be used in the display unit 6502, the control device 6509, etc. By using a semiconductor device according to one aspect of the present invention in the control device 6509, power consumption can be reduced, and therefore it is preferred.

[0542] The display unit 6502 may use a display panel according to one aspect of the present invention.

[0543] Figure 27B It is a cross-sectional schematic diagram of one end of the microphone 6506, including the frame 6501.

[0544] A light-transmitting protective component 6510 is provided on one side of the display surface of the frame 6501. The space surrounded by the frame 6501 and the protective component 6510 contains a display panel 6511, an optical component 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc.

[0545] The display panel 6511, optical component 6512, and touch sensor panel 6513 are fixed to the protective component 6510 using an adhesive layer (not shown).

[0546] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and this folded portion is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals disposed on a printed circuit board 6517.

[0547] The display panel 6511 can be a flexible display according to one aspect of the present invention. This allows for the realization of an extremely lightweight electronic device. Furthermore, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while minimizing the thickness of the electronic device. Additionally, by folding a portion of the display panel 6511 to provide a connection to the FPC 6515 on the back of the pixel portion, a narrow-bezel electronic device can be realized. Figure 27C An example of a television device is shown. In the television device 7100, a display unit 7000 is assembled in a frame 7101. Here is shown the structure in which the frame 7101 is supported by a bracket 7103.

[0549] It can be operated using the operating switches provided in the housing 7101 and the separately provided remote control 7111. Figure 27C The operation of the television device 7100 shown is illustrated. Alternatively, a touch sensor may be provided in the display unit 7000, allowing operation of the television device 7100 by touching the display unit 7000 with a finger or the like. Furthermore, a display unit for displaying data output from the remote control 7111 may be provided in the remote control 7111. Channel and volume adjustments can be made using the operation keys or touch panel provided in the remote control 7111, and the images displayed on the display unit 7000 can also be manipulated.

[0550] Furthermore, the television device 7100 includes a receiver and a modem. It can receive general television broadcasts using the receiver. Moreover, it can connect to a wired or wireless communication network via the modem to conduct one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0551] Figure 27DAn example of a notebook computer is shown. The notebook computer 7200 includes a chassis 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, a control device 7216, etc. A display unit 7000 is assembled in the chassis 7211. The control device 7216 includes, for example, one or more selected from a CPU, a GPU, and a storage device. A semiconductor device according to one aspect of the present invention can be used in the display unit 7000, the control device 7216, etc. By using a semiconductor device according to one aspect of the present invention in the control device 7216, power consumption can be reduced, and therefore it is preferred.

[0552] Figure 27E and Figure 27F Here is an example of digital signage.

[0553] Figure 27E The digital sign 7300 shown includes a frame 7301, a display unit 7000, and a speaker 7303. It may also include LEDs, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc. Figure 27F A digital sign 7400 is shown mounted on a cylindrical column 7401. The digital sign 7400 includes a display section 7000 disposed along the curved surface of the column 7401.

[0555] The larger the display unit (7000), the more information it can provide at once. A larger display unit (7000) is also more likely to attract attention, which can improve the effectiveness of advertising.

[0556] By using a touch panel in the display unit 7000, not only can static or dynamic images be displayed on the display unit 7000, but users can also operate it intuitively, making it preferable. Furthermore, when used to provide information such as route information or traffic information, intuitive operation enhances ease of use.

[0557] like Figure 27E and Figure 27F As shown, digital signage 7300 or digital signage 7400 preferably connects wirelessly with information terminal devices 7311 or 7411, such as smartphones carried by the user. For example, advertising information displayed on display unit 7000 can be displayed on the screen of information terminal device 7311 or information terminal device 7411. Furthermore, the display on display unit 7000 can be switched by operating information terminal device 7311 or information terminal device 7411.

[0558] Furthermore, the game can be executed on the digital signage 7300 or 7400 using the screen of information terminal device 7311 or 7411 as the operating unit (controller). Thus, multiple users can participate in the game simultaneously and enjoy the experience.

[0559] exist Figures 27C to 27F In this embodiment, the display panel of one aspect of the present invention can be used in the display unit 7000.

[0560] Figures 28A to 28G The electronic device shown includes a frame 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), a connection terminal 9006, a sensor 9007 (which has the function of sensing, detecting, and measuring the following factors: force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, tilt, vibration, odor, or infrared radiation), a microphone 9008, etc.

[0561] Figures 28A to 28G The electronic device shown has various functions. For example, it may have the following functions: displaying various information (still images, moving images, and text images, etc.) on a display unit; a touch panel function; displaying a calendar, date, or time, etc.; controlling processing using various software (programs); wireless communication function; reading and processing programs or data stored in a storage medium; etc. Note that the functions of the electronic device are not limited to the above functions, but can have various functions. The electronic device may include multiple display units. In addition, a camera or the like may be installed in the electronic device to give it the following functions: capturing still or moving images and storing the captured images in a storage medium (external storage medium or storage medium built into the camera); displaying the captured images on a display unit; etc.

[0562] The following is a detailed explanation. Figures 28A to 28G The electronic device shown.

[0563] Figure 28A This is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 can be used, for example, as a smartphone. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, etc., may also be included in the portable information terminal 9101. Furthermore, as a portable information terminal 9101, text or image information can be displayed on multiple surfaces. Figure 28AThe image shows an example displaying three icons 9050. Furthermore, information 9051, shown as a dashed rectangle, can be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of received emails, SNS messages, or phone calls; the subject of the email or SNS message; the sender's name; the date; the time; remaining battery level; and radio wave strength. Alternatively, icons 9050 can be displayed in the same location where information 9051 is displayed.

[0564] Figure 28B This is a perspective view showing a portable information terminal 9102. The portable information terminal 9102 has the function of displaying information on three or more surfaces of the display unit 9001. Here, examples are shown where information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9102 is placed in a jacket pocket, the user can check the information 9053 displayed in a position seen from above the portable information terminal 9102. For example, the user can check this display without taking the portable information terminal 9102 out of their pocket, thereby determining whether to answer a phone call.

[0565] Figure 28C This is a perspective view of a tablet terminal 9103. The tablet terminal 9103 can, for example, execute various application software such as mobile phone, email, and article reading and editing, music playback, network communication, and computer games. The tablet terminal 9103 includes a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the frame 9000; operation keys 9005 serving as operating buttons on the left side of the frame 9000; and a connection terminal 9006 on the bottom surface.

[0566] Figure 28D This is a perspective view showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smartwatch (registered trademark). Furthermore, the display surface of the display unit 9001 is curved, allowing display along its curved surface. Additionally, the portable information terminal 9200 can perform hands-free calls, for example, by communicating with a headset capable of wireless communication. Furthermore, by utilizing the connection terminal 9006, the portable information terminal 9200 can transmit data or charge with other information terminals. Charging can also be performed wirelessly.

[0567] Figures 28E to 28G This is a perspective view showing the foldable portable information terminal 9201. Furthermore, Figure 28E This is a 3D view of the portable information terminal 9201 in its unfolded state. Figure 28G It is a 3D image of the folded state. Figure 28F From Figure 28E status and Figure 28G The portable information terminal 9201 is a three-dimensional representation of the state transitioning between different states. In its folded state, it is highly portable, while in its unfolded state, it offers excellent browsing capabilities due to its large, seamlessly integrated display area. The display unit 9001 included in the portable information terminal 9201 is supported by three frames 9000 connected by hinges 9055. The display unit 9001 can be bent, for example, within a radius of curvature of 0.1 mm or more and 150 mm or less. At least a portion of this embodiment can be implemented in combination with other embodiments and examples described in this specification. [Example 1]

[0569] In this embodiment, the manufacturing process includes... Figures 1A to 1D The semiconductor device 200 shown (hereinafter referred to as sample 1A) is analyzed, and the results of cross-sectional STEM image observation, electrical characteristic evaluation, and reliability evaluation are presented. In this embodiment, the semiconductor device 200 is used based on... Figures 10A to 15C Sample 1A was manufactured using the method described herein.

[0570] First, the structure of sample 1A will be described. For example... Figures 1A to 1DAs shown, sample 1A includes an insulator 212 disposed on a substrate (not shown), an insulator 214 on the insulator 212, an insulator 216 on the insulator 214, and conductors 205 (conductors 205a and 205b) disposed in the insulator 216. Furthermore, it includes an insulator 221 on the insulator 216 and conductor 205, an insulator 222 on the insulator 221, and an insulator 224 on the insulator 222. Additionally, it includes an oxide 230 (oxide 230a and oxide 230b) on the insulator 224, conductors 242a and 242b on the oxide 230, an insulator 271a (insulators 271a1 and 271a2) on the conductor 242a, and an insulator 271b (insulators 271b1 and 271b2) on the conductor 242b. Furthermore, the structure includes an insulator 250 (insulator 250a, insulator 250b, insulator 250c, and insulator 250d) on oxide 230, and a conductor 260 (conductor 260a and conductor 260b) on the insulator 250. Additionally, an insulator 275 is included on insulator 271a and insulator 271b, and an insulator 280 is included on insulator 275. The insulator 250 and conductor 260 are embedded within openings in insulator 280 and insulator 275. Furthermore, an insulator 282 (insulator 282a and insulator 282b) is included on insulator 280 and conductor 260, an insulator 283 is included on insulator 282, and an insulator 285 is included on insulator 283. Furthermore, insulators 285, 283, 282, 280, 275, 271a, and 271b have openings leading to conductor 242a and conductor 242b. Conductor 240a (conductor 240a1 and conductor 240a2) and insulator 241a are embedded inside the openings leading to conductor 242a, and conductor 240b (conductor 240b1 and conductor 240b2) and insulator 241b are embedded inside the openings leading to conductor 242b.

[0571] Insulator 212 is a silicon nitride film with a thickness of 60 nm deposited by sputtering. Insulator 214 is an aluminum oxide film with a thickness of 40 nm deposited by sputtering. In addition, insulator 216 is a silicon oxide film deposited by sputtering.

[0572] Conductor 205 is a stacked film of conductors 205a and 205b. Conductor 205a is a titanium nitride film deposited using CVD. Conductor 205b is a tungsten film deposited using CVD.

[0573] Insulator 221 is a silicon nitride film with a thickness of 5 nm deposited using the PEALD method. Insulator 222 is a hafnium oxide film with a thickness of 15 nm deposited using the thermal ALD method. Insulator 224 is a silicon oxide film with a thickness of 20 nm deposited using the sputtering method.

[0574] Oxide 230 is a stacked film of oxides 230a and 230b. As oxide 230a, an In-Ga-Zn oxide with a thickness of 10 nm was deposited by sputtering. Note that in the deposition of oxide 230a, a target with an In:Ga:Zn ratio of 1:3:2 (atomic number ratio) was used. The deposition conditions for oxide 230a were as follows: oxygen gas at 90 sccm and argon gas at 10 sccm were used as deposition gases; the deposition pressure was 0.5 Pa; the deposition power was set to 2000 W using an RF power supply; and the substrate temperature was 250 °C.

[0575] As oxide 230b, an In-Ga-Zn oxide with a thickness of 15 nm was deposited by sputtering. Note that in the deposition of oxide 230b, a target with an In:Ga:Zn ratio of 1:1:1.2 [atomic number ratio] was used. The deposition conditions for oxide 230b were as follows: oxygen gas at 90 sccm and argon gas at 10 sccm as deposition gases, a deposition pressure of 0.5 Pa; a deposition power of 2000 W using an RF power supply; and a substrate temperature of 250 °C.

[0576] Furthermore, after depositing the oxide 230b film, a heat treatment is performed. As this heat treatment, an atmospheric pressure heat treatment is performed at 400°C for 1 hour in a mixed atmosphere with a N2 gas flow rate of 4 slm and an O2 gas flow rate of 1 slm.

[0577] Conductors 242a and 242b are tantalum nitride films with a thickness of 20 nm deposited by sputtering. The deposition conditions for conductors 242a and 242b are as follows: tantalum is used as the target material; nitrogen gas at 19 sccm and argon gas at 58 sccm are used as deposition gases; the deposition pressure is 0.5 Pa; the deposition power is set to 1000 W using a DC power supply; and the substrate temperature is room temperature.

[0578] Insulator 271a is a stacked film of insulators 271a1 and 271a2, and insulator 271b is a stacked film of insulators 271b1 and 271b2. Insulators 271a1 and 271b1 are silicon nitride films with a thickness of 5 nm deposited by sputtering. Insulators 271a2 and 271b2 are silicon oxide films with a thickness of 10 nm deposited by sputtering.

[0579] Insulator 275 is a ...

Claims

1. A semiconductor device comprising: an oxide semiconductor; a first conductor and a second conductor over the oxide semiconductor and apart from each other; a first insulator provided over the first conductor and the second conductor and having an opening overlapping with a region between the first conductor and the second conductor; a second insulator provided in the opening of the first insulator and in contact with a top surface of the oxide semiconductor, side surfaces of the first conductor and the second conductor, and a side surface of the first insulator; a third conductor provided over the second insulator in the opening of the first insulator and having a region overlapping with the oxide semiconductor with the second insulator interposed therebetween; a third insulator in contact with a top surface of the third conductor, an upper end portion of the second insulator, and a top surface of the first insulator; a fourth insulator in contact with a top surface of the third insulator; a fifth insulator in contact with a top surface of the fourth insulator; a fourth conductor provided in an opening formed in the first insulator, the third insulator, the fourth insulator, and the fifth insulator and reaching the opening of the first conductor; and a fifth conductor provided in an opening formed in the first insulator, the third insulator, the fourth insulator, and the fifth insulator and reaching the opening of the second conductor, wherein the third insulator and the fourth insulator are each a metal oxide, and a carbon concentration of the third insulator is higher than that of the fourth insulator.

2. The semiconductor device according to claim 1, wherein the third insulator and the fourth insulator each include aluminum oxide.

5. The semiconductor device according to any one of claims 1 to 4, wherein the fifth insulator includes silicon nitride.

3. The semiconductor device according to claim 2, wherein the third insulator has a carbon concentration of 1 x 1018 atoms / cm3 or more and 1 x 1020 atoms / cm3 or less. 19 atoms / cm3 or more and 1 x 1020 atoms / cm3 or less. 21 atoms / cm 3 The following regions.

4. The semiconductor device according to claim 3, wherein the fourth insulator has a carbon concentration of 4.46 × 10⁻⁶. 17 atoms / cm 3 Above and 1×10 19 atoms / cm 3 The following areas.

6. A method for manufacturing a semiconductor device, comprising the steps of: forming a transistor including an oxide semiconductor, a first conductor and a second conductor over the oxide semiconductor and apart from each other, a first insulator provided over the first conductor and the second conductor and having an opening overlapping with a region between the first conductor and the second conductor, a second insulator provided in the opening of the first insulator and in contact with a top surface of the oxide semiconductor, side surfaces of the first conductor and the second conductor, and a side surface of the first insulator, and a third conductor provided over the second insulator in the opening of the first insulator and having a region overlapping with the oxide semiconductor with the second insulator interposed therebetween; depositing a third insulator so as to be in contact with a top surface of the third conductor, an upper end portion of the second insulator, and a top surface of the first insulator; depositing a fourth insulator so as to be in contact with a top surface of the third insulator; depositing a fifth insulator so as to be in contact with a top surface of the fourth insulator; forming an opening reaching the first conductor and an opening reaching the second conductor in the first insulator, the third insulator, the fourth insulator, and the fifth insulator; subjecting the first insulator to a heat treatment; ​ a fourth conductor is formed in the opening reaching the first conductor and a fifth conductor is formed in the opening reaching the second conductor; in the deposition of the third insulator, aluminum oxide is deposited by a thermal ALD method; and in the deposition of the fourth insulator, aluminum oxide is deposited by a sputtering method in an oxygen-containing atmosphere.

7. The method for manufacturing a semiconductor device according to claim 6, wherein the heat treatment is performed at 350 °C or higher and 450 °C or lower in an atmosphere containing a nitrogen gas.

8. The method for manufacturing a semiconductor device according to claim 7, wherein in the deposition of the fifth insulator, silicon nitride is deposited by a sputtering method.

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