Liquid crystal display device

Abstract

The present invention provides a method for fabricating a transistor in a semiconductor device using an oxide semiconductor film that has stable electrical characteristics and low signal delay due to wiring resistance, a semiconductor device having the transistor, and a high-performance display device having the transistor. [Solution] In a semiconductor device, a method for manufacturing source electrodes and drain electrodes in contact with an oxide semiconductor film 108 involves forming first metal films 110a, 112a and second metal films 110b, 112b, performing a first photolithography step on the second metal film to remove a portion of the second metal film by first etching, forming third metal films 110c, 112c on the first and second metal films, performing a second photolithography step on the third metal film to remove portions of the first and third metal films by second etching. Furthermore, the second etching removes the first and third metal films outside the edge of the second metal film removed by the first etching.

Description

[Technical Field]

[0001] This invention relates to semiconductor devices and methods for manufacturing semiconductor devices. It also relates to display devices having said semiconductor devices. Regarding installation and electronic equipment. [Background technology]

[0002] A transistor (thin film transistor) is formed using a semiconductor thin film on a substrate having an insulating surface. The technology for constructing transistors (also called TFTs) is attracting attention. These transistors are integrated circuits. It is widely applied in electronic devices such as integrated circuits (ICs) and image display devices (display devices). Although silicon-based semiconductor materials are widely known as semiconductor thin films applicable to inverters, Oxide semiconductors are attracting attention as another material.

[0003] For example, as an oxide semiconductor, Zn-O-based oxide or In-Ga-Zn-O-based oxide A technique for fabricating transistors using this method has been disclosed (see Patent Documents 1 and 2). ).

[0004] Furthermore, in display devices using transistors (e.g., liquid crystal panels, organic EL panels) The screen size is tending to get larger. Along with the increase in screen size, transistors and other components are becoming more complex. In the case of a display device using active elements, the voltage applied to the element is due to the wiring resistance. The position of the wiring can vary, resulting in a decrease in display quality, such as uneven display or poor gradation. That was the problem.

[0005] Furthermore, the screen resolution of the display device is high-definition (HD, 1366×768), High-definition picture quality (FHD, 1920×1080) and the trend towards higher resolution are increasing. The development of display devices for so-called 4K digital cinema, such as 3840×2048 or 4096×2180, is also being rushed. The development of display devices for so-called 4K digital cinema, such as 3840×2048 or 4096×2180, is also being rushed.

[0006] As the resolution of the screen of the display device improves, the drive frequency used in the drive circuit and the like of the display device also tends to increase, and for wiring or signal lines, etc., the application of a low-resistance material with less signal delay is desired. As the resolution of the screen of the display device improves, the drive frequency used in the drive circuit and the like of the display device also tends to increase, and for wiring or signal lines, etc., the application of a low-resistance material with less signal delay is desired. As the resolution of the screen of the display device improves, the drive frequency used in the drive circuit and the like of the display device also tends to increase, and for wiring or signal lines, etc., the application of a low-resistance material with less signal delay is desired.

[0007] Conventionally, an aluminum film has been widely used as a material for wiring or signal lines. However, research and development using a copper film is actively underway for further reduction of resistance. However, the copper film has drawbacks such as weak adhesion to the underlying film and the copper element in the copper film being likely to diffuse into the semiconductor layer of the transistor and deteriorate the transistor characteristics. Therefore, in order to improve the adhesion to the underlying film and prevent the diffusion of copper elements, a silicon nitride film, a copper alloy layer formed on the silicon nitride film, and a pure copper layer formed on the copper alloy layer are used to fabricate a transistor. (See Patent Document 3). However, research and development using a copper film is actively underway for further reduction of resistance. However, the copper film has drawbacks such as weak adhesion to the underlying film and the copper element in the copper film being likely to diffuse into the semiconductor layer of the transistor and deteriorate the transistor characteristics. Therefore, in order to improve the adhesion to the underlying film and prevent the diffusion of copper elements, a silicon nitride film, a copper alloy layer formed on the silicon nitride film, and a pure copper layer formed on the copper alloy layer are used to fabricate a transistor. (See Patent Document 3). However, research and development using a copper film is actively underway for further reduction of resistance. However, the copper film has drawbacks such as weak adhesion to the underlying film and the copper element in the copper film being likely to diffuse into the semiconductor layer of the transistor and deteriorate the transistor characteristics. Therefore, in order to improve the adhesion to the underlying film and prevent the diffusion of copper elements, a silicon nitride film, a copper alloy layer formed on the silicon nitride film, and a pure copper layer formed on the copper alloy layer are used to fabricate a transistor. (See Patent Document 3). However, research and development using a copper film is actively underway for further reduction of resistance. However, the copper film has drawbacks such as weak adhesion to the underlying film and the copper element in the copper film being likely to diffuse into the semiconductor layer of the transistor and deteriorate the transistor characteristics. Therefore, in order to improve the adhesion to the underlying film and prevent the diffusion of copper elements, a silicon nitride film, a copper alloy layer formed on the silicon nitride film, and a pure copper layer formed on the copper alloy layer are used to fabricate a transistor. (See Patent Document 3). However, research and development using a copper film is actively underway for further reduction of resistance. However, the copper film has drawbacks such as weak adhesion to the underlying film and the copper element in the copper film being likely to diffuse into the semiconductor layer of the transistor and deteriorate the transistor characteristics. Therefore, in order to improve the adhesion to the underlying film and prevent the diffusion of copper elements, a silicon nitride film, a copper alloy layer formed on the silicon nitride film, and a pure copper layer formed on the copper alloy layer are used to fabricate a transistor. (See Patent Document 3). However, research and development using a copper film is actively underway for further reduction of resistance. However, the copper film has drawbacks such as weak adhesion to the underlying film and the copper element in the copper film being likely to diffuse into the semiconductor layer of the transistor and deteriorate the transistor characteristics. Therefore, in order to improve the adhesion to the underlying film and prevent the diffusion of copper elements, a silicon nitride film, a copper alloy layer formed on the silicon nitride film, and a pure copper layer formed on the copper alloy layer are used to fabricate a transistor. (See Patent Document 3).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] In Patent Document 1, a silicon-based semiconductor is used as a semiconductor thin film applicable to a transistor. The material is a prerequisite. Therefore, a transient using an oxide semiconductor film as the channel formation region. There are issues with applying it to the standard, such as the manufacturing method not being optimal or the structure not being optimal. there were.

[0010] In view of these problems, in one aspect of the present invention, a semiconductor device using an oxide semiconductor film... Furthermore, transistors possess stable electrical characteristics and low signal delay due to wiring resistance. One of the objectives is to provide a method for manufacturing a transistor. One of the objectives is to provide a device. Also, a high-performance display device having the transistor. One of the objectives is to provide it. [Means for solving the problem]

[0011] A transistor with a bottom gate structure that uses an oxide semiconductor film as the channel formation region. In a method for fabricating a semiconductor device, source electrodes and drain electrodes are brought into contact with an oxide semiconductor film. The source electrode and drain electrode are composed of first to third metal films, and the The metal film in step 2 uses a material containing copper.

[0012] As a method for fabricating source and drain electrodes that come into contact with an oxide semiconductor film, a first metal film A second metal film is formed, and the first photolithography process is performed on the second metal film. A portion of the second metal film is removed by the first etching. Then, the first metal film and the second A third metal film is formed on the metal film, and a second photolithography process is performed on the third metal film. The process is carried out to remove a portion of the first metal film and the third metal film by the second etching. Furthermore, the second etching is performed on the edges of the second metal film that were removed by the first etching. On the side, the first metal film and the third metal film are removed. By using this manufacturing method, the The metal film 2 is covered by the first metal film and the third metal film (more preferably, Because it is enclosed, the copper-containing material used for the second metal film diffuses into the oxide semiconductor film. This can suppress the following. More details are as follows:

[0013] One aspect of the present invention is a step of forming a gate electrode and forming a gate insulating film on the gate electrode. The process involves forming an oxide semiconductor film at a position that is in contact with the gate insulating film and overlaps with the gate electrode. The process includes a step of forming a source electrode and a drain electrode on an oxide semiconductor film. In a method for manufacturing a conductive device, the source electrode and the drain electrode are made of a first metal film and a second metal The process involves forming a metal film and performing a first photolithography process on the second metal film. A step of removing a portion of the metal film by first etching, and the first metal film and the second metal film The process involves forming a third metal film on top of the third metal film, and performing a second photolithography process on the third metal film. The process involves removing a portion of the first metal film and the third metal film by second etching. The second etching includes etching the edges of the second metal film that were removed by the first etching. This is a method for manufacturing a semiconductor device in which the first metal film and the third metal film are removed from the outside.

[0014] In the above manufacturing method, a first insulating film is formed on the source electrode and the drain electrode. The process involves forming an insulating film, introducing oxygen onto the first insulating film, and forming a second insulating film onto the first insulating film. A step of forming an insulating film, a step of forming an aluminum film on the second insulating film, and aluminum A process of introducing oxygen onto a nium film to form an aluminum oxide film, and aluminum oxide The configuration may also include a step of forming a planar insulating film on a nium film.

[0015] Furthermore, in each of the above manufacturing methods, the first metal film and the third metal film are made of tungsten, A metal film containing one or more elements selected from tantalum, titanium, and molybdenum, The first layer is preferably a metal nitride film. The second metal film may also contain copper.

[0016] Furthermore, in each of the above manufacturing methods, the first etching is performed using the wet etching method. For the second etching step, a dry etching method is recommended.

[0017] Another aspect of the present invention includes a gate electrode and a gate insulating film formed on the gate electrode. And, an oxide semiconductor film formed in a position that is in contact with the gate insulating film and superimposed on the gate electrode, and acid It has a source electrode and a drain electrode formed on a semiconductor film, and the source electrode and drain The rain electrode consists of a first metal film, a second metal film, and a third metal film, and the second metal film This is a semiconductor device formed in the region inside the edges of the first and third metal films. ru.

[0018] Another aspect of the present invention includes a gate electrode and a gate insulating film formed on the gate electrode. And, an oxide semiconductor film formed in a position that is in contact with the gate insulating film and superimposed on the gate electrode, and acid Source electrode and drain electrode formed on a semiconductor film, and the source electrode is electrically connected It has a signal line, and the signal line has a first metal film, a second metal film, and a third metal film. Therefore, the second metal film is formed in the region inward from the edges of the first and third metal films. The source electrode and drain electrode are semiconductors consisting of a first metal film and a third metal film. It is a device.

[0019] In the above configuration, further, an oxygen-excess type first insulator is placed on the source electrode and the drain electrode. A border film, a second insulating film formed on the first insulating film, and an oxide film formed on the second insulating film. The structure includes an aluminum film and a planar insulating film formed on the aluminum oxide film. That's fine.

[0020] Furthermore, in each of the above configurations, the first metal film and the third metal film are tungsten, tantalum A metal film containing one or more elements selected from tungsten, titanium, and molybdenum, or a metal The first film should be a nitride film. The second metal film should also contain copper.

[0021] Furthermore, in each of the above configurations, the gate electrode is made of tungsten, tantalum, titanium, molybdenum, It may contain one or more elements selected from den and copper.

[0022] Furthermore, display devices and electronic devices having the above-mentioned semiconductor devices are also included in the scope of the present invention. . [Effects of the Invention]

[0023] In a semiconductor device using an oxide semiconductor film, the following are desired: stable electrical characteristics and wiring resistance This provides a method for fabricating transistors with minimal signal delay caused by [the aforementioned factor]. A semiconductor device having the transistor can be provided. It is possible to provide a high-performance display device. [Brief explanation of the drawing]

[0024] [Figure 1] A plan view and a cross-sectional view showing one embodiment of a semiconductor device. [Figure 2] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 3] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 4] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 5] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 6] A plan view and a cross-sectional view showing one embodiment of a semiconductor device. [Figure 7] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 8] A cross-sectional view showing an example of the manufacturing process for a semiconductor device. [Figure 9] A plan view showing one embodiment of a display device. [Figure 10] A cross-sectional view showing one embodiment of a display device. [Figure 11] A cross-sectional view showing one embodiment of a display device. [Figure 12] A diagram showing an example of electronic equipment, including a semiconductor device. [Figure 13] A diagram showing an example of a tablet device including a semiconductor device. [Modes for carrying out the invention]

[0025] The embodiments of the invention disclosed herein will be described in detail below with reference to the drawings. However, the present invention is not limited to the following description and does not deviate from the spirit and scope of the present invention. It is easily understood by those skilled in the art that its form and details can be changed in various ways. Therefore, the present invention shall not be construed as being limited to the embodiments described below. .

[0026] For the sake of ease of understanding, the position, size, and scope of each component shown in the drawings, etc., are as follows: The actual location, size, and range may not be represented. Therefore, the disclosed invention may not reflect the actual location, size, or range. It is not necessarily limited to the location, size, or scope disclosed in drawings, etc.

[0027] In this specification, ordinal numbers such as "1st," "2nd," and "3rd" refer to the constituent elements. This note is added to avoid confusion and does not imply a numerical limitation.

[0028] In this specification, the terms "above" and "below" refer to the relative positions of the constituent elements, not just "directly above". This does not necessarily mean "directly below". For example, "gate electric field on gate insulating film" If the expression is "pole," then excludes those that include other components between the gate insulating film and the gate electrode. do not.

[0029] Furthermore, in this specification, the terms "electrode" and "wiring" refer to these components functionally. It is not limited to this. For example, "electrode" can be used as part of "wiring". And the reverse is also true. Furthermore, the terms "electrode" and "wiring" can refer to multiple "electrodes" and This includes cases where the wiring is formed as an integrated unit.

[0030] Furthermore, the "source" and "drain" functions are used when employing transistors with different polarities. For example, the direction of the current may change during circuit operation. Therefore, in this specification, the terms "source" and "drain" may be used interchangeably. It is assumed that this is possible.

[0031] Furthermore, in this specification, "electrically connected" means "having some kind of electrical effect." This includes cases where the connection is made via ". Here, "has some electrical effect The term "of" is not particularly limited as long as it enables the exchange of electrical signals between connected objects. For example, "things that have some kind of electrical effect" include electrodes and wiring, as well as transistors. Switching elements such as resistors, inductors, capacitors, and other various functional elements are available. This includes elements such as [specific components].

[0032] In this specification, patterning refers to the process using photolithography. However, patterning is not limited to the photolithography process, but also to photolithography Other processes can also be used. Additionally, masks formed in the photolithography process can be used. These will be removed after etching.

[0033] (Embodiment 1) In this embodiment, one form of a semiconductor device and a method for manufacturing a semiconductor device is shown in Figures 1 to 5. This will be explained using the following. In this embodiment, an oxide semiconductor film is used as an example of a semiconductor device. This indicates a lunge.

[0034] <Example of semiconductor device configuration 1> Figure 1 shows an example of the configuration of transistor 150. Figure 1(A) is a planar view of transistor 150. Figure 1(B) is a cross-sectional view of Figure 1(A) along X1-Y1, and Figure 1(C) is This is a cross-sectional view of V1-W1 in Figure 1(A). Note that Figure 1(A) is complicated. To avoid this, some of the components of transistor 150 (e.g., gate insulating film 106) The diagram omits some details.

[0035] The transistor 150 shown in Figure 1 has a gate electrode 104 formed on the substrate 102, and A gate insulating film 106 formed on the gate electrode 104, and a gate insulating film 106 in contact with the gate insulating film 106, An oxide semiconductor film 108 formed in a position overlapping with electrode 104, and an oxide semiconductor film 10 It is configured to include a source electrode 110 and a drain electrode 112 formed on 8.

[0036] Furthermore, the gate electrode 104 is connected to the first gate electrode 104a and the second gate electrode 104b. It is composed of the following. The first gate electrode 104a is made of tungsten, tantalum, titanium, Using a metal film or metal nitride film containing one or more elements selected from molybdenum It is preferable that the second gate electrode 104b contains copper. For example, In this embodiment, a tungsten film is used as the first gate electrode 104a, A copper film is used as the gate electrode 104b of 2. The gate electrode 104 has such a layered structure and This makes it possible to have a low-resistance gate electrode 104. Note that the first gate electrode 1 By providing 04a, the substrate 102 and the copper film used as the second gate electrode 104b are Copper in the copper film used to improve adhesion and / or as a second gate electrode 104b It can suppress the diffusion of elements.

[0037] Furthermore, the gate insulating film 106 consists of a first gate insulating film 106a and a second gate insulating film 10 It is composed of 6b. The first gate insulating film 106a is the second gate electrode 104b It is sufficient that the silicon nitride film has the function of suppressing the diffusion of copper elements in the copper film used as such. Using silicon nitride film, aluminum oxide film, aluminum nitride film, etc. This can be achieved. In addition, the second gate insulating film 106b is formed later on the oxide semiconductor film 108 It is sufficient if it has the function of supplying oxygen, such as silicon oxide film, silicon oxide nitride film, etc. It can be used. For example, in this embodiment, the first gate insulating film 106a and Then, using a silicon nitride film, a silicon oxide nitride film is used as the second gate insulating film 106b. This is used. By using such a layered structure for the gate insulating film 106, the gate electrode 104 and This suppresses the diffusion of copper elements in the copper film used, and also in the oxide semiconductor film 108 that is formed later. It can supply oxygen.

[0038] Furthermore, the source electrode 110 has a first metal film 110a, a second metal film 110b, and a third The drain electrode 112 is composed of a metal film 110c and a first metal film 112a and It is composed of two metal films 112b and a third metal film 112c. Film 110b and the second metal film 112b are the first metal film 110a and the first metal film 112a , formed in the region inside the edges of the third metal film 110c and the third metal film 112c .

[0039] Furthermore, the first metal film 110a, the first metal film 112a, the third metal film 110c, and As for the metal film 112c of 3, among tungsten, tantalum, titanium, and molybdenum... It is preferable to use a metal film or metal nitride film containing one or more elements selected from the above. The second metal film 110b and the second metal film 112b preferably contain copper. .

[0040] For example, in this embodiment, the first metal film 110a and the first metal film 112a and For the first, a tungsten film is used, and for the second metal film 110b and the second metal film 112b, A copper film is used, and the third metal film 110c and the third metal film 112c are tantalum nitride films. It is used. In addition, the second metal film 110b and the second metal film 112b are used with respect to the first metal film 110 a and the third metal film 110c and the third metal film 11 are formed on the first metal film 112a. It is covered by 2c.

[0041] In other words, the copper films used as the second metal film 110b and the second metal film 112b are on the bottom surface The tungsten films used as the first metal film 110a and the first metal film 112a Covered, the top and sides are used as third metal films 110c and 112c. It is covered with a tantalum oxide film. First metal film 110a and first metal film 112a, Furthermore, the third metal film 110c and the third metal film 112c suppress the diffusion of copper elements in the copper film. It has the function of a barrier metal.

[0042] By using a source electrode 110 and drain electrode 112 with this configuration, low resistance is achieved. It can be a source electrode 110 and a drain electrode 112, and the source electrode 110, Furthermore, it suppresses the diffusion of copper elements from the copper film used in the drain electrode 112 to the outside. It is possible.

[0043] For example, a method for forming the source electrode 110 and the drain electrode 112 is to use an oxide semiconductor. A first metal film and a second metal film are formed on film 108, and the first photolithography is applied to the second metal film. A etching process is performed, and a portion of the second metal film is removed by the first etching, and the second gold The metal film 110b and the second metal film 112b are formed. Then the first metal film and the second metal film The second metal film is covered on the group film (the second metal film 110b and the second metal film 112b). A third metal film is formed on it. Then, a second photolithography process is performed on the third metal film. The first metal film and a portion of the third metal film are removed by the second etching, and the first gold Metal film 110a, first metal film 112a, third metal film 110c, and third metal film 112 c is formed. By using this manufacturing method, the copper film used as the second metal film is acid Since there is no direct contact with the oxide semiconductor film 108, backcharging of the oxide semiconductor film 108 This can suppress the diffusion of impurities (especially copper elements) that may be mixed into the flannel portion.

[0044] Furthermore, an oxygen-rich first insulating layer is placed on the source electrode 110 and the drain electrode 112. A film 114a, a second insulating film 114b formed on the first insulating film 114a, and a second insulating film Aluminum oxide film 116 formed on edge film 114b, and aluminum oxide film 116 The configuration may also include a planar insulating film 118 formed thereon.

[0045] For details on other components, see the transistor 150 shown in Figure 1, which will be described later. The manufacturing method will be explained using Figures 2 to 5.

[0046] <Method 1 for fabricating semiconductor devices> First, the substrate 102 includes a first gate electrode 104a and a second gate electrode 104b. A gate electrode 104 is formed (see Figure 2(A)).

[0047] There are no major restrictions on the substrate that can be used for substrate 102, but at the very least, the subsequent heat treatment It is necessary to have sufficient heat resistance to withstand the stresses. For example, barium borosilicate Various types of glass substrates used in the electronics industry, such as glass and aluminoborosilicate glass. A lath substrate can be used. The substrate should have a thermal expansion coefficient of 25 × 10⁻⁶. -7 / ℃ 50 x 10 -7 / ℃ or less (preferably 30 × 10 -7 / ℃ or higher 40×10 -7 / ℃ The following conditions apply, and the strain point is between 650°C and 750°C (preferably between 700°C and 740°C). It is preferable to use a substrate that is as follows:

[0048] Also, the 5th generation (1000mm x 1200mm or 1300mm x 1500mm), 6th generation (1500mm x 1800mm), 7th generation (1870mm x 2200mm), 8th generation (2200mm x 2500mm), 9th generation (2400mm x 2800mm), When using large glass substrates such as the 10th generation (2880mm x 3130mm), semiconductors Shrinkage of the substrate caused by heat treatment during the manufacturing process of the device makes fine processing difficult. This can happen. Therefore, when using a large glass substrate as described above, shrinkage may occur. It is preferable to use materials with less carbon. For example, as a substrate, preferably 450°C, Preferably, the amount of shrinkage after heat treatment at a temperature of 500°C for 1 hour is 20 ppm or less. A large glass substrate with a concentration of 10 ppm or less, and more preferably 5 ppm or less, is used. Yes.

[0049] Alternatively, a flexible substrate may be used as the substrate 102 to fabricate the semiconductor device. To fabricate a semiconductor device, a transient containing an oxide semiconductor film 108 is laid on a flexible substrate. The substrate 150 may be fabricated directly, or a transistor containing the oxide semiconductor film 108 may be fabricated on another substrate. Zista 150 may be fabricated, then peeled off and transferred to a flexible substrate. Transistor 15 containing the fabricated substrate and oxide semiconductor film for peeling and transferring onto a flexible substrate. It is preferable to provide a release layer between 0 and 0.

[0050] Alternatively, an underlayer insulating film may be provided on the substrate 102. The underlayer insulating film may be a plasma CV film. By method D or sputtering, silicon oxide, silicon oxide nitride, aluminum oxide Oxide insulating films such as aluminum oxide nitride, hafnium oxide, and gallium oxide, nitride silicon, silicon nitride oxide, aluminum nitride, aluminum nitride oxide, and other nitride materials It can be formed using a border film or a mixture of these materials.

[0051] The substrate 102 may also be subjected to heat treatment. For example, heat treatment may be performed using a high-temperature gas. Using a GRTA (Gas Rapid Thermal Anneal) device, at 650°C Then, heat treatment should be performed for 1 to 5 minutes. Note that the high-temperature gas in GRTA is Argo Noble gases such as nitrates, or inert gases such as nitrogen, that do not react with the material being treated by heat treatment. This is used. Alternatively, heat treatment may be performed in an electric furnace at 500°C for 30 minutes to 1 hour. .

[0052] The gate electrode 104 is made from tungsten, tantalum, titanium, molybdenum, and copper, selected from among these materials. It can be formed using a material containing one or more selected elements. In this embodiment, As the second gate electrode 104b, a sputtering method was used to create a film thickness of 100 nm or more. A copper film of 0 nm or less is formed. Also, the copper element in the copper film is formed as the lower layer of the second gate electrode 104b. A first gate electrode 104a is formed, which functions as a barrier metal to suppress the diffusion of elemental particles. In this embodiment, the first electrode 104a is formed using a sputtering method to create a film. A tantalum nitride film with a thickness of 20 nm to 100 nm is formed.

[0053] In this embodiment, the first gate electrode 104a and the second gate electrode 1 The stacked structure of 04b will be described, but it is not limited to this configuration. For example, the second gate A third gate electrode may be provided on electrode 104b. The same material as that used for the first gate electrode 104a can be used.

[0054] Next, a first gate insulating film 106a and a second gate insulating film 104 are applied to the substrate 102 and the gate electrode 104. A gate insulating film 106 containing the gate insulating film 106b is formed (see Figure 2(B)).

[0055] The first gate insulating film 106a is coated by plasma CVD or sputtering, etc. Form a film thickness of 10 nm to 100 nm, more preferably 20 nm to 50 nm. It is preferable to use the following nitride insulating films. For example, silicon nitride film, silicon oxide film Examples include a film. The first gate insulating film 1 is in contact with the substrate 102 and the gate electrode 104. As 06a, by using a nitride insulating film, from the substrate 102 or gate electrode 104 It has the effect of suppressing the diffusion of impurities. In particular, gate electrode 104 (more specifically the second gate When a metal material containing copper is used for the gate electrode 104b, the first gate insulating film 106a This makes it possible to suppress the diffusion of copper elements into the oxide semiconductor film 108.

[0056] In this embodiment, the first gate insulating film 106a is formed using the plasma CVD method. A silicon nitride film with a thickness of 50 nm is used. As a deposition gas for the silicon nitride film, for example... For example, a mixed gas of silane (SiH4) and nitrogen, or silane, nitrogen and ammonia (NH4). 3) The mixed gas, etc., can be used.

[0057] The second gate insulating film 106b is formed by a plasma CVD method, a sputtering method, or the like to form an oxide insulating film having a film thickness of 100 nm or more and 350 nm or less, more preferably 100 nm or more and 200 n m or less. For example, a silicon oxide film, a gallium oxide film, an aluminum oxide film, a silicon oxynitride film, an aluminum oxynitride film, and the like can be mentioned .

[0058] In addition, as the material of the second gate insulating film 106b, hafnium oxide, yttrium oxide , hafnium silicate (HfSi x O y (x>0, y>0)), hafnium silicate with nitrogen added (HfSiO N x (x>0, y>0)), hafnium aluminate ( y HfAl O x (x>0, y>0)), high-k materials such as lanthanum oxide, etc. can be used to reduce the gate leakage current. y

[0059] In this embodiment, a silicon oxynitride film with a film thickness of 200 nm is formed as the second gate insulating film 106b by a plasma CVD method. The plasma CVD method can reduce the film formation time compared with the sputtering method. In addition, the plasma CVD method has less variation in film thickness in the plane where the film is formed than the sputtering method, and it is also less likely to cause contamination by particles.

[0060] Note that the second gate insulating film 106b is an insulating film that contacts the oxide semiconductor film 108, so it is preferably an insulating film containing oxygen, and it is preferably free from impurities such as water and hydrogen as much as possible. However, in the plasma CVD method, compared with the sputtering method Therefore, it is difficult to reduce the hydrogen concentration in the film. A heat treatment (dehydration) is performed on the edge film 106b for the purpose of reducing, and more preferably removing, hydrogen atoms. (Chemicalization or dehydrogenation treatment) may be performed.

[0061] The heat treatment temperature is 250°C to 650°C, preferably 450°C to 600°C. Alternatively, the temperature should be below the substrate's strain point. For example, when introducing a substrate into an electric furnace, which is one of the heat treatment devices. The gate insulating film 106 was then heated at 650°C for 1 hour under a vacuum (reduced pressure) atmosphere. To carry out the right thing.

[0062] Furthermore, heat treatment equipment is not limited to electric furnaces; it also includes heat conduction or heat from heat-generating elements such as resistance heating elements. A device that heats the object to be processed by radiation may also be used. For example, GRTA(Gas R apid Thermal Anneal) equipment, LRTA (Lamp Rapid T RTA (Rapid Thermal Annealing) devices such as hermal annealing equipment al) equipment can be used. LRTA equipment uses halogen lamps, metal halide lamps. Lamps, xenon arc lamps, carbon arc lamps, high-pressure sodium lamps, high-pressure mercury lamps This is a device that heats an object to be processed by radiating light (electromagnetic waves) from a lamp or similar light source. The GRTA apparatus is a device that performs heat treatment using high-temperature gas. The high-temperature gas is a Inert gases such as argon or nitrogen, which do not react with the material being treated during heat treatment. A gas is used. Furthermore, when using a GRTA device as the heat treatment device, during the process... Because the interval is short, heating the substrate in an inert gas heated to a high temperature of 650°C to 700°C is also possible. stomach.

[0063] The heat treatment involves nitrogen, oxygen, and ultra-dry air (with a water content of 20 ppm or less, preferably 1 ppm). Air (m or less, more preferably 10 ppb or less), or noble gas (argon, helium) It is fine to carry it out in an atmosphere such as the above, but the atmosphere of nitrogen, oxygen, ultra-dry air, or noble gas, etc. It is preferable that the gas does not contain water, hydrogen, etc. Also, nitrogen and acid are introduced into the heat treatment device. The purity of the element or noble gas is 6N (99.9999%) or higher, preferably 7N (99.99%). The impurity concentration should be 999% or higher (i.e., 1 ppm or less, preferably 0.1 ppm or less). It is preferable.

[0064] Heat treatment can be used to dehydrate or dehydrogenate the gate insulating film 106, A gate insulating film free of impurities such as hydrogen or water that cause variations in the characteristics of the inverter. 106 can be formed.

[0065] Furthermore, the heat treatment for dehydration or dehydrogenation may be carried out multiple times, and may be combined with other heat treatments. You may sleep.

[0066] Next, an oxide semiconductor film is placed in contact with the gate insulating film 106 and superimposed on the gate electrode 104. Forms 108 (see Figure 2(C)).

[0067] The oxide semiconductor film 108 may have a single-layer structure or a multi-layer structure. The oxide semiconductor film 108 may be amorphous or crystalline. If a structure is to be formed, the oxide semiconductor film 108 will be heat-treated in a later manufacturing process. A crystalline oxide semiconductor film may be obtained by crystallizing an amorphous oxide semiconductor film. The heat treatment temperature is 250°C to 700°C, preferably 400°C or higher, more preferably The temperature should be 500°C or higher, more preferably 550°C or higher. Note that this heat treatment is performed during the manufacturing process. It can also be used in conjunction with other heat treatments at that stage.

[0068] The deposition methods for oxide semiconductor film 108 include sputtering and MBE (Molecular Beam). Beam Epitaxy, plasma CVD, pulsed laser deposition, ALD (A Methods such as tomic layer deposition can be used as appropriate.

[0069] When forming the oxide semiconductor film 108, the hydrogen contained in the oxide semiconductor film 108 should be minimized as much as possible. It is preferable to reduce the concentration. To reduce the hydrogen concentration, for example, sputtering can be used. When performing film deposition using this method, the atmospheric gas supplied to the processing chamber of the sputtering apparatus and Then, high-purity noble gas (typical) is obtained from which impurities such as hydrogen, water, hydroxyl groups, or hydrides have been removed. Argon, oxygen, and mixed gases of noble gases and oxygen are used as appropriate.

[0070] Furthermore, while removing residual moisture in the processing chamber, the sputtering gas from which hydrogen and water have been removed is then processed. By introducing this and performing film deposition, the hydrogen concentration of the deposited oxide semiconductor film 108 can be reduced. This can be done. To remove residual moisture in the processing chamber, an adsorption type vacuum pump, for example, It is preferable to use a lyopump, ion pump, or titanium sublimation pump. Alternatively, a turbomolecular pump with a cold trap may be added. (Cryopon) P is, for example, a hydrogen molecule, a compound containing a hydrogen atom such as water (H2O) (more preferably carbon Because of the high exhaust capacity of compounds (including those containing atoms), a treatment room was evacuated using a cryopump. This method can reduce the concentration of impurities in the oxide semiconductor film 108 that has been formed.

[0071] In this embodiment, the oxide semiconductor film 108 is made up of a material with an atomic ratio of In:Ga:Zn. A metal oxide target with an atomic ratio of 1:1:1, or a metal oxide with an atomic ratio of In:Ga=2:1. A material target is used, and the film is deposited by sputtering. However, the oxide semiconductor film 108 The targets that can be used are not limited to these target materials and compositions. No. Also, the oxide semiconductor film 108 is subjected to a noble gas (typically argon) atmosphere. Formed by sputtering in an oxygen atmosphere or a mixed atmosphere of a noble gas and oxygen. It is possible. Also, the targets that can be used for the oxide semiconductor film 108 are simple Crystalline targets such as crystalline or polycrystalline materials are preferred. As a result, the formed thin film also has crystalline properties, and in particular, the c-axis of the formed thin film is It tends to form crystals that are oriented in a certain direction.

[0072] Furthermore, immediately after deposition, the oxide semiconductor film 108 has an excess of oxygen in its composition compared to its stoichiometric composition. It is preferable to bring it to a saturated state. For example, when using the sputtering method to make an oxide semiconductor film 1 When forming a film of O8, it is preferable to form the film under conditions where oxygen makes up a large proportion of the deposition gas. In particular, it is preferable to perform film formation in an oxygen atmosphere (100% oxygen gas). For example, oxide semiconductors As the conductive film 108, an In-Ga-Zn oxide (IGZO) was used, and the oxygen of the film deposition gas When forming a film under conditions where the proportion of oxygen is high (especially in an atmosphere of 100% oxygen gas), the film formation temperature will be 30 Even at temperatures above 0°C, the release of Zn from the film is suppressed.

[0073] Furthermore, the oxide semiconductor film 108 is made of gold with the aforementioned atomic ratio of In:Ga:Zn=1:1:1. When formed using an oxide target, the composition of the target and the thin layer formed on the substrate are important. The film composition may differ. For example, a metal oxide with In:Ga:Zn = 1:1:1. When using a target, although it depends on the film deposition conditions, the oxide semiconductor film 108 is a thin film. The composition may be such that the atomic ratio is In:Ga:Zn = 1:1:0.6~0.8. In the deposition of the oxide semiconductor film 108, Zn sublimes, or In, Ga, Zn This is thought to be because the sputtering rates of each component are different.

[0074] Therefore, when you want to form a thin film with a desired composition, you should first target a metal oxide The composition of the original material needs to be adjusted. For example, the composition of the oxide semiconductor film 108, which is a thin film, needs to be adjusted. When the atom ratio is In:Ga:Zn=1:1:1, the metal oxide target The composition should be set to an atomic ratio of In:Ga:Zn = 1:1:1.5. That is, a metallic acid The Zn content of the ionized target should be increased beforehand. However, the composition of the target is as follows: The values ​​are not limited to those mentioned above and can be adjusted as appropriate depending on the film formation conditions and the composition of the thin film formed. It is possible. Also, by increasing the Zn content of the metal oxide target, the thin This is preferable because it improves the crystallinity of the film.

[0075] Furthermore, when depositing the oxide semiconductor film 108 by sputtering, the metal acid used for film deposition The relative density of the monoxide target is 90% or more and 100% or less, preferably 95% or more, more preferably The density should be 99.9% or higher. By using a metal oxide target with a high relative density... This allows the deposited oxide semiconductor film 108 to be made into a dense film.

[0076] Furthermore, forming the oxide semiconductor film 108 while the substrate 102 is held at a high temperature is also possible. This is effective in reducing the concentration of impurities that may be contained in the ionized semiconductor film 108. The heating temperature should be between 150°C and 450°C, preferably 170°C or lower. The temperature should be kept below 350°C. Also, heating the substrate at a high temperature during film formation can help to reduce crystalline acidity. A crystalline semiconductor film 108 can be formed.

[0077] The oxide semiconductor used in the oxide semiconductor film 108 is at least indium (In) Alternatively, it is preferable to include zinc (Zn). In particular, it is preferable to include both In and Zn. Furthermore, to reduce variations in the electrical characteristics of transistors using the oxide semiconductor, It is preferable to have gallium (Ga) in addition to those as a stabilizer. It is preferable to have tin (Sn) as a stabilizer. It is preferable to have hafnium (Hf). Also, aluminum is preferred as a stabilizer. It is preferable to have aluminum (Al). Also, zirconium (Zr) as a stabilizer. It is preferable that it has

[0078] Other stabilizers include lanthanides such as lanthanum (La) and cerium. (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europieu Eu, Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Ho Lumium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), It may contain one or more types of lutetium (Lu).

[0079] For example, oxide semiconductors include indium oxide, tin oxide, zinc oxide, and in-Zn-based acids. compounds, Sn-Zn oxides, Al-Zn oxides, Zn-Mg oxides, Sn-Mg acids In-Mg oxides, In-Ga oxides, In-Ga-Zn oxides (IGZO (Also written as), In-Al-Zn oxide, In-Sn-Zn oxide, Sn-Ga- Zn oxides, Al-Ga-Zn oxides, Sn-Al-Zn oxides, In-Hf-Z n-based oxides, In-La-Zn oxides, In-Ce-Zn oxides, In-Pr-Zn oxides In-Nd-Zn oxides, In-Sm-Zn oxides, In-Eu-Zn oxides Oxides, In-Gd-Zn oxides, In-Tb-Zn oxides, In-Dy-Zn acids In-Ho-Zn oxides, In-Er-Zn oxides, In-Tm-Zn oxides Materials, In-Yb-Zn oxides, In-Lu-Zn ​​oxides, In-Sn-Ga-Zn oxides Oxides, In-Hf-Ga-Zn oxides, In-Al-Ga-Zn oxides, In-S n-Al-Zn oxides, In-Sn-Hf-Zn oxides, In-Hf-Al-Zn Oxides can be used.

[0080] For example, in-Ga-Zn oxides are those whose main components are In, Ga, and Zn. It means an oxide containing In, and the ratio of In, Ga, and Zn is not specified. Also, In and Other metal elements besides Ga and Zn may be present.

[0081] In addition, as an oxide semiconductor, InMO3(ZnO) m (m>0, and m is not an integer) Materials represented by ) may also be used. Note that M is selected from Ga, Fe, Mn, and Co. It represents one or more metallic elements. Also, as an oxide semiconductor, In2SnO 5(ZnO) n Materials expressed as (n>0 and n is an integer) may also be used.

[0082] For example, In:Ga:Zn=1:1:1 (=1 / 3:1 / 3:1 / 3), In:Ga: Zn=2:2:1 (=2 / 5:2 / 5:1 / 5), or In:Ga:Zn=3:1: In-Ga-Zn oxides with an atomic ratio of 2 (=1 / 2:1 / 6:1 / 3) and their compositions The surrounding oxides can be used. Alternatively, In:Sn:Zn = 1:1:1 (= 1 / 3 :1 / 3:1 / 3), In:Sn:Zn = 2:1:3 (=1 / 3:1 / 6:1 / 2) In:Sn:Zn = 2:1:5 (= 1 / 4:1 / 8:5 / 8) is the atomic ratio of In-S It is preferable to use n-Zn oxides or oxides with a similar composition.

[0083] However, this is not limited to these, and includes the required semiconductor characteristics (mobility, threshold, variability, etc.). Depending on the situation, you should use one with an appropriate composition. Also, in order to obtain the required semiconductor properties, Carrier concentration, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. It is preferable to make it appropriate.

[0084] For example, high mobility can be obtained relatively easily with In-Sn-Zn oxides. However, However, even with In-Ga-Zn oxides, mobility can be increased by lowering the bulk defect density. It can be raised.

[0085] For example, if the atomic ratio of In, Ga, and Zn is In:Ga:Zn = a:b:c(a+b The composition of an oxide with +c=1 is such that the atomic ratio is In:Ga:Zn=A:B:C(A+B+ The composition of the oxide C=1) is in the vicinity of (aA) 2 +(bB) 2 +(cC) 2 ≤r 2 This means satisfying the following condition. For example, r can be set to 0.05. The same applies to other oxides.

[0086] Furthermore, the oxide semiconductor film 108 is CAAC-OS(C Axis Aligned C A rystalline oxide semiconductor film is preferred. It's nice.

[0087] CAAC-OS films are neither perfectly single crystals nor perfectly amorphous. The film is an oxide semiconductor layer with a crystalline-amorphous multiphase structure, having a crystalline portion within an amorphous phase. The crystalline portion is often small enough to fit within a cube with sides less than 100 nm long. Transmission electron microscope (TEM) Observation using an microscope (scope) shows the boundary between the amorphous and crystalline parts of the CAAC-OS film. The boundaries are not clear. Also, TEM revealed grain boundaries in the CAAC-OS film. (Also known as Lee) cannot be confirmed. Therefore, the CAAC-OS film does not exhibit electron transfer due to grain boundaries. The decrease in mobility is suppressed.

[0088] The crystalline portion contained in the CAAC-OS film has a c-axis that is the normal vector to the surface on which the CAAC-OS film is formed. Aligned in a direction parallel to the normal vector of the tor or surface, and viewed from a direction perpendicular to the ab plane, three It has a horn-shaped or hexagonal atomic arrangement, and when viewed from a direction perpendicular to the c-axis, the metal atoms are layered or The metal atoms and oxygen atoms are arranged in layers. Furthermore, the a-axis is defined between different crystalline regions. The orientation of the b-axis may also be different. In this specification, when simply referred to as vertical, The range of 85° to 95° is also included. Furthermore, when simply describing something as parallel, - This includes the range of 5° to 5°.

[0089] Furthermore, the distribution of crystalline regions in the CAAC-OS film does not need to be uniform. For example, CA In the formation process of an AC-OS film, when crystal growth is performed from the surface side of the oxide semiconductor film, The proportion of crystalline material may be higher near the surface compared to near the formation surface. Also, C By adding impurities to the AAC-OS film, the crystalline region in the impurity-added area becomes non-crystalline. It can also crystallize.

[0090] The c-axis of the crystalline portion contained in the CAAC-OS film is the normal vector to the surface on which the CAAC-OS film is formed. Because it aligns in a direction parallel to the normal vector of the tor or surface, the shape of the CAAC-OS film (covering shape) Depending on the cross-sectional shape of the surface (or the shape of the surface itself), they may face in different directions. The direction of the c-axis of the crystalline portion is the normal vector of the surface to which the CAAC-OS film was formed. The direction is parallel to the normal vector of the torso or surface. The crystalline part is formed by deposition. Alternatively, it is formed by performing crystallization treatments such as heat treatment after film formation.

[0091] Transistors using CAAC-OS film exhibit changes in electrical properties due to irradiation with visible or ultraviolet light. The dynamics are small. Therefore, this transistor is highly reliable.

[0092] When a CAAC-OS film is applied as the oxide semiconductor film 108, the CAAC-OS film There are three ways to obtain it. The first is to set the film deposition temperature to between 100°C and 450°C. More preferably, the oxide semiconductor layer is formed at a temperature of 150°C to 400°C, and the surface This method involves roughly aligning the c axis vertically. The second method involves depositing an oxide semiconductor layer with a thin film thickness. Subsequently, a heat treatment is performed at a temperature between 200°C and 700°C to orient the c axis approximately perpendicular to the surface. Yes. The third method involves forming a thin film as the first layer, followed by heat treatment at a temperature between 200°C and 700°C. This method involves performing a process, depositing a second layer, and orienting the film approximately perpendicular to the surface along the c axis.

[0093] Furthermore, the oxide semiconductor film 108 may be an oxide semiconductor film having crystalline properties other than the CAAC-OS film. When depositing a conductive film (single crystal or microcrystal), the deposition temperature is not particularly limited.

[0094] Furthermore, the oxide semiconductor film 108 has an energy gap of 2.8 eV to 3.2 eV. Furthermore, it is larger compared to the energy gap of silicon, which is 1.1 eV. The true carrier density of 10⁸ is 10 -9 cm -3 Therefore, the intrinsic carrier density of silicon is 10 11 cm -3 It is extremely small in comparison.

[0095] The majority carriers (electrons) of the oxide semiconductor film 108 flow from the transistor source. Furthermore, it is possible to completely deplete the channel formation region, so the transient It is possible to make the off-current of the transistor extremely small. A transistor using oxide semiconductor film 108 The off-current of the inverter is 10 yA / μm or less at room temperature, and also at 85°C to 95°C. The value is less than 1 zA / μm, which is extremely small.

[0096] Furthermore, the oxide semiconductor film 108 may have a structure in which multiple oxide semiconductor layers are stacked. For example, the oxide semiconductor film 108 is constructed by stacking a first oxide semiconductor layer and a second oxide semiconductor layer. Then, using metal oxides of different compositions in the first oxide semiconductor layer and the second oxide semiconductor layer... This may also be done. For example, a ternary metal oxide may be used for the first oxide semiconductor layer, and the second oxide semiconductor A binary metal oxide may be used for the conductive layer. Alternatively, the first oxide semiconductor layer and the second oxide The semiconductor layer may also be made of oxides of ternary metals.

[0097] Furthermore, the constituent elements of the first oxide semiconductor layer and the second oxide semiconductor layer are the same, and the combination of the two The composition may be different. For example, the atomic ratio of the first oxide semiconductor layer may be In:Ga:Zn = The ratio is set to 1:1:1, and the atomic ratio of the second oxide semiconductor layer is set to In:Ga:Zn=3:1:2. Alternatively, the atomic ratio of the first oxide semiconductor layer may be set to In:Ga:Zn = 1:3:2. Alternatively, the atomic ratio of the second oxide semiconductor layer may be set to In:Ga:Zn = 2:1:3.

[0098] At this time, of the first oxide semiconductor layer and the second oxide semiconductor layer, the side closer to the terminal electrode ( It is preferable to set the content of In and Ga in the oxide semiconductor layer (channel side) to In > Ga. The In and Ga content of the oxide semiconductor layer on the side furthest from the electrode (back channel side) is determined by the In It is best to set ≤Ga. In oxide semiconductors, the s orbitals of heavy metals mainly contribute to carrier conduction. In this case, increasing the In content tends to increase the overlap of the s orbitals. Therefore, oxides with a composition of In > Ga have a higher composition than oxides with a composition of In ≤ Ga. It possesses mobility. Furthermore, Ga has a greater energy for forming oxygen vacancies compared to In, resulting in oxygen depletion. Because loss is less likely to occur, oxides with a composition of In≦Ga are different from oxides with a composition of In>Ga. It possesses comparatively stable properties. Therefore, the oxidation on the channel side results in an In > Ga composition. A monocrystalline semiconductor layer is applied, and an oxide semiconductor layer with a composition of In≦Ga is applied to the back channel side. This makes it possible to further improve the mobility and reliability of the transistors.

[0099] Furthermore, when the oxide semiconductor film 108 is stacked, the first oxide semiconductor layer and the second oxide semiconductor layer The conductive layer may also be made of an oxide semiconductor with a different crystalline structure. That is, a single-crystal oxide semiconductor Body, polycrystalline oxide semiconductor, amorphous oxide semiconductor, or crystalline oxide semiconductor (e.g.) For example, a configuration in which CAAC-OS is appropriately combined may be used. Also, the first oxide semiconductor An amorphous oxide semiconductor is applied to at least one of the body layer and the second oxide semiconductor layer. This relieves internal and external stresses in the oxide semiconductor, reducing variations in transistor characteristics. This reduces the transistor's reliability, which in turn reduces its performance. Ion semiconductors readily absorb donor impurities such as hydrogen, and are also prone to oxygen deficiencies. Therefore, it is easily converted to n-type. For this reason, the oxide semiconductor layer on the channel side has crystalline properties. It is preferable to use an oxide semiconductor (for example, CAAC-OS).

[0100] Furthermore, the combination of composition and crystallinity when the oxide semiconductor film 108 is stacked is as follows: For example, starting from the gate insulating film 106 side, the number of atoms in the vicinity of In:Ga:Zn=1:1:1 A amorphous oxide semiconductor layer with an atomic ratio of In:Ga:Zn = 3:1:2 and a crystalline acid Stacked structure with a crystalline semiconductor layer, or crystallinity with an atomic ratio of In:Ga:Zn = 1:1:1. An oxide semiconductor layer and a crystalline oxide semiconductor with an atomic ratio of In:Ga:Zn = 3:1:2. One example is a layered structure with multiple layers. Another example of a layered configuration is In:Ga:Zn=3 A crystalline oxide semiconductor layer with an atomic ratio of approximately 1:2 and an In:Ga:Zn=1:1:1 neighborhood. It may also be a laminated structure with a crystalline oxide semiconductor layer. Other laminated configurations include: An amorphous oxide semiconductor layer with an atomic ratio of In:Ga:Zn = 1:1:1 and In:Ga: A stacked structure with an amorphous oxide semiconductor layer having an atomic ratio of Zn = 3:1:2, or In:Ga Amorphous oxide semiconductor layer with an atomic ratio of approximately Zn=3:1:2 and In:Ga:Zn=1: A stacked structure with amorphous oxide semiconductor layers having an atomic ratio close to 1:1 is also possible.

[0101] Furthermore, before the deposition of the oxide semiconductor film 108, a planarization treatment is performed on the surface of the oxide semiconductor film 108 to be deposited. A planarization treatment may be performed. The planarization treatment is not particularly limited, but polishing treatment (for example, chemical Chemical Mechanical Polishing (CMP) Methods such as dry etching and plasma treatment can be used.

[0102] Plasma processing is, for example, a reverse plasma treatment that generates plasma by introducing argon gas. Sputtering can be performed. Reverse sputtering is performed in an argon atmosphere with a rounded edge on the substrate side. This refers to a method of modifying the surface of a substrate by applying a voltage using an F power supply to form plasma near the substrate. Note that nitrogen, helium, oxygen, etc. may be used instead of argon. Reverse sputtering When this is done, powdery substances (particles, etc.) adhering to the film-forming surface of the oxide semiconductor film 108 are removed. It can remove (also known as mit).

[0103] Even if polishing, dry etching, and plasma treatment are performed multiple times as planarization treatments, Often, these can be combined. Also, when combining them, the order of the steps is not particularly important. It is not limited to this setting and should be set appropriately according to the unevenness of the surface to which the oxide semiconductor film 108 is deposited. .

[0104] Furthermore, after the oxide semiconductor film 108 is formed, excess water contained in the oxide semiconductor film 108 Heat treatment to reduce or remove elements (including water and hydroxyl groups) (dehydration or dehydrogenation) It is preferable to do so. Regarding the heat treatment conditions, compared to the second gate insulating film 106b mentioned above, This can be carried out under the same conditions as the heat treatment performed by [the other method].

[0105] This heat treatment imparts n-type conductivity to the oxide semiconductor film 108. Hydrogen can be reduced, and more preferably removed. Also, the second gate insulating film 106b When an insulating film containing oxygen is used, this heat treatment results in the second gate insulating film 106b The oxygen contained in is supplied to the oxide semiconductor film 108. Dehydration of the oxide semiconductor film 108. Alternatively, oxygen that is simultaneously removed by dehydrogenation treatment is supplied from the second gate insulating film 106b. By doing so, it is possible to fill the oxygen vacancies in the oxide semiconductor film 108.

[0106] Furthermore, after heating the oxide semiconductor film 108 by heat treatment, the heating temperature is maintained, or the heating temperature is maintained. While slowly cooling from the temperature, high-purity oxygen gas, high-purity nitrous oxide gas, or ultra-high-purity oxygen gas is added to the same furnace. Dry air (measured using a CRDS (cavity ring-down laser spectroscopy) dew point meter) When set, the moisture content is 20 ppm or less (equivalent to a dew point of -55°C), preferably 1 ppm or less. More preferably, air with a concentration of 10 ppb or less may be introduced. Oxygen gas or dinitrate monoxide may also be introduced. It is preferable that the base gas does not contain water, hydrogen, etc. Alternatively, the acid introduced into the heat treatment apparatus may be... The purity of the elemental gas or nitrous oxide gas is 6N or higher, preferably 7N or higher (i.e., oxygen gas) (or the impurity concentration in the nitrous oxide gas is 1 ppm or less, preferably 0.1 ppm or less.) It is preferable to do so. Dehydration or dehydration by the action of oxygen gas or nitrous oxide gas. The oxide semiconductor film 10, which was simultaneously reduced by the impurity removal process through hydrogenation treatment. By supplying oxygen, which is the main component material of 8, the oxide semiconductor film 108 is increased It can be purified and converted to type i (true) purity.

[0107] Heat treatment for dehydration or dehydrogenation is another heat treatment in the manufacturing process of transistor 150. It can also be used for both purposes.

[0108] Next, source electrode and drain are placed on the gate insulating film 106 and oxide semiconductor film 108. A first metal film 109a that serves as an electrode (including wiring formed in the same layer), and a second A metal film 109b is formed (see Figure 2(D)).

[0109] The first metal film 109a is tungsten, tantalum, titanium, and molybdenum. Preferably, it is a metal film or metal nitride film containing one or more elements selected from among them. In this embodiment, the first metal film 109a is formed using a sputtering method. A tungsten film with a thickness of 50 nm is used.

[0110] Furthermore, the first metal film 109a may be in a laminated structure. For example, the first metal film 109a The first layer is selected from tungsten, tantalum, titanium, and molybdenum. Use a metal film containing one or more elements. As the second layer of the first metal film 109a, a laminated structure of a metal nitride film containing one or more elements selected from tungsten nitride, tantalum nitride, titanium nitride, and molybdenum nitride can be mentioned. Since the first metal film 109a is in contact with the oxide semiconductor film 108, a material that does not extract oxygen from the oxide semiconductor film 108 to cause n-type conversion, or a material that does not diffuse into the oxide semiconductor film 108 to cause n-type conversion is used. Also, the first metal film 109a is preferably made of a material (so-called barrier metal material) that suppresses the diffusion of copper elements from the copper film used for the second metal film 109b into the oxide semiconductor film 108. As the second metal film 109b, it is preferable that the film contains copper elements. Note that copper alloys obtained by adding several weight % of aluminum, gold, silver, zinc, tin, nickel, etc. to copper may also be used.

[0111] In this embodiment, a copper film with a thickness of 200 nm formed by sputtering is used as the second metal film 109b. Next, a resist is applied on the second metal film 109b, and the first patterning is performed to form a resist mask 141 (see Fig. 2(E)). The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced.

[0112] The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. In this embodiment, a copper film with a thickness of 200 nm formed by sputtering is used as the second metal film 109b. In this embodiment, a copper film with a thickness of 200 nm formed by sputtering is used as the second metal film 109b.

[0113] Next, a resist is applied on the second metal film 109b, and the first patterning is performed to form a resist mask 141 (see Fig. 2(E)). The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced.

[0114] The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask 141 by an inkjet method does not require the use of a photomask, so the manufacturing cost can be reduced. The resist mask 141 can be formed by applying a photosensitive resin and then exposing and developing the photosensitive resin. Note that the photosensitive resin may be either a positive-type or negative-type resin. Also, the resist mask 141 may be formed by an inkjet method. Forming the resist mask​

[0115] Next, a portion of the second metal film 109b is removed by the first etching, and the second metal film 1 Forms 10b and a second metal film 112b (see Figure 3(A)).

[0116] As a method for removing the second metal film 109b, a wet etching method is preferable. Furthermore, the chemical used in the wet etching method is the etching solution for the second metal film 109b. Any chemical solution that can be used and does not cause the first metal film 109a to disappear is acceptable, for example, the first A tungsten film is used as the first metal film 109a, and a copper film is used as the second metal film 109b. If used, the chemical solution should be a mixture of water, hydrogen peroxide, and carboxylic acid, or water, phosphoric acid, and nitric acid. A mixture of sulfuric acid and potassium sulfate can be used.

[0117] Furthermore, by adjusting the wet etching time and performing isotropic etching, the resist mass is formed. The sides of the second metal film 110b and the second metal film 112b are located inside the side of the 141. A recessed shape is also acceptable.

[0118] Next, remove the resist mask 141 (see Figure 3(B)).

[0119] The method for removing the resist mask 141 is a wet removal method using a stripping solution, or a p Dry removal methods such as lazma treatment, or removal methods combining these methods, are used. It is possible.

[0120] Next, on the first metal film 109a, the second metal film 110b, and the second metal film 112b This forms a third metal film 109c (see Figure 3(C)).

[0121] As the third metal film 109c, the same method and materials as those for the first metal film 109a can be used. In this embodiment, as the third metal film 109c, a tantalum nitride film with a thickness of 100 nm formed by a sputtering method is used.

[0122] Next, a resist is applied onto the third metal film 109c, and second patterning is performed to form a resist mask 142 (see Fig. 3(D)). The resist mask 142 can be formed by the same materials and method as those for the resist mask 141.

[0123]

[0124] Next, a part of the first metal film 109a and the third metal film 109c is removed by second etching to form the first metal film 110a, the first metal film 112a, the third metal film 110c, and the third metal film 112c (see Fig. 4(A)).

[0125]

[0126] Second etching removes the first metal film 109a and the third metal film 109c outside the ends of the second metal film 110b and the second metal film 112b removed by the first etching.

[0127] When a tungsten film is used as the first metal film 109a and a tantalum nitride film is used as the third metal film 109c, a mixed gas of SF6 and O2, or a mixed gas of SF6 and BCl3, etc. can be used as the gas for the dry etching method. <00009�7><00�0978> Furthermore, during etching of the first metal film 109a and the third metal film 109c, The etching conditions are optimized so that the semiconductor film 108 is not etched and fragmented. It is desirable that the first metal film 109a and the third metal film 109c are used. To etch the oxide semiconductor film 108 without etching it at all is to obtain the condition that It is difficult, and oxide semiconductors are difficult to etch during the etching of the first metal film 109a and the third metal film 109c. The conductive film 108 is an oxide semiconductor film 108 which is partially etched and has grooves (recesses) It can happen.

[0128] Next, the resist mask 142 is removed, and the first metal film 110a and the second metal film 110b are removed. A source electrode 110 consisting of a first metal film 112a and a third metal film 110c, and a source electrode 110 consisting of a first metal film 112a and a second metal film 112a and a third metal film 110c. A drain electrode 112 is formed, consisting of a metal film 112b and a third metal film 112c. (See Figure 4(B)).

[0129] By using this method for forming the source electrode 110 and drain electrode 112, oxidation The material semiconductor film 108 (more specifically, the back channel side) is connected to the second metal film 110b, and Since it does not come into contact with the copper film used for the second metal film 112b, the oxide semiconductor film 108 It can suppress copper elements that may adhere or diffuse.

[0130] Furthermore, the method for removing the resist mask 142 is the same as the method for removing the resist mask 141. This can be done using a similar method.

[0131] Furthermore, after the formation of the source electrode 110 and the drain electrode 112, the oxide semiconductor film 108( More specifically, it is preferable to clean the back channel side. For cleaning, for example, oxygen plasma treatment or cleaning treatment using dilute hydrofluoric acid. These are effective. By performing such cleaning, the source electrode 110 and the drain Etching gas components used during the formation of the in electrode 112, or residue from the resist mask 142 These can be removed from the oxide semiconductor film 108, resulting in a higher purity oxide semiconductor film 108. It can be transformed.

[0132] Furthermore, heat treatment may be performed after the formation of the source electrode 110 and the drain electrode 112. The temperature of the heat treatment is 250°C to 650°C, preferably 450°C to 600°C. or below the circuit board's strain point.

[0133] Through the above steps, the transistor 150 shown in this embodiment is formed.

[0134] Next, on transistor 150, more specifically oxide semiconductor film 108, source electrode 110 , and a first insulating film 114a is formed on the drain electrode 112. Then the first insulating film Oxygen 145 is introduced into 114a and the oxide semiconductor film 108 (see Figure 4(C)).

[0135] The first insulating film 114a is formed by plasma CVD and sputtering. It can produce silicon oxide films, gallium oxide films, aluminum oxide films, and silicon nitride oxide films. A film, or an oxide insulating film such as an aluminum oxide nitride film, can be used. The thickness of film 114a is preferably 50 nm or more and 100 nm or less.

[0136] Furthermore, it is preferable that the first insulating film 114a be an oxygen-rich oxide insulating film. By using an oxygen-excess type oxide insulating film, oxygen can be suitably supplied to the oxide semiconductor film 108. It is possible.

[0137] In this embodiment, the first insulating film 114a is a 30 nm film produced by plasma CVD. A silicon oxide nitride film is formed. The film formation conditions for the first insulating film 114a are, for example, SiH4 The gas flow rate ratio of SiH4:N2O is set to SiH4:N2O = 20 sccm:3000 sccm, and the pressure The current is set to 200 Pa, the RF power supply (power output) to 100 W, and the substrate temperature to 350°C ± 1 A temperature of 5°C is sufficient. The first insulating film 114a is an insulating film in contact with the oxide semiconductor film 108. Since it is a film, it should contain as few impurities as possible, such as water and hydrogen, similar to the gate insulating film 106. It is preferable.

[0138] Oxygen-145 consists of at least oxygen radicals, ozone, oxygen atoms, and oxygen ions (min It contains either a minor ion or a cluster ion.

[0139] The introduction of oxygen 145 into the first insulating film 114a can be done, for example, by ion implantation, ion doping Using methods such as the ion implantation method, plasma immersion ion implantation method, and plasma treatment. This is possible. Furthermore, a gas cluster ion beam may be used as the ion implantation method. Furthermore, the introduction of oxygen 145 may treat the entire surface of the first insulating film 114a at once, for example. For example, a linear ion beam may be used. When using a linear ion beam, the substrate Alternatively, by relatively moving (scanning) the ion beam, the entire first insulating film 114a can be scanned. Oxygen 145 can be introduced to the surface.

[0140] Any gas containing oxygen (O) can be used as the supply gas for oxygen-145, for example, O2 gas. N2O gas, CO2 gas, CO gas, NO2 gas, etc. can be used. The supply gas may contain a noble gas (e.g., Ar).

[0141] Furthermore, for example, when introducing oxygen using ion implantation, the dose of oxygen 145 is 1 × 1 0 13 ions / cm 2 The above 5 x 10 16 ions / cm 2 The following is preferable: The oxygen content in the first insulating film 114a after the element introduction treatment is determined by the chemical composition of the first insulating film 114a. It is preferable to exceed the stoichiometric composition. The oxygen injection depth depends on the injection conditions. It can be controlled as needed.

[0142] Furthermore, the first insulating film 114a may be an oxide insulating film (for example, a silicon oxide film or a nitrogen oxide film). When using a silicon oxide film, oxygen is one of the main component materials in the oxide insulating film. Yes. Therefore, the oxygen concentration in the oxide insulating film is measured using SIMS (Secondary Ion It is difficult to estimate accurately using methods such as mass spectrometry. Therefore, it is difficult to determine whether or not oxygen was intentionally added to the oxide insulating film. It can be said that this is the case. Also, excess oxygen contained in the first insulating film 114a can lead to the formation of oxide semi-oxides in later processes. The same applies when supplied to the conductive film 108.

[0143] By the way, oxygen contains 17 O or 18 Isotopes such as 0 exist, and these in nature It is known that their relative abundances are approximately 0.038% and 0.2% of the total oxygen atoms, respectively. In other words, in the insulating film in contact with the oxide semiconductor film (in this embodiment, the first insulating film) 114a) The concentrations of these isotopes in oxide semiconductor films can be determined by methods such as SIMS. Since it can be estimated by this, by measuring these concentrations, oxides To more accurately estimate the oxygen concentration in an insulating film in contact with a semiconductor film, or in an oxide semiconductor film. This may be possible. Therefore, by measuring these concentrations, it is possible to determine the concentration of the oxide semiconductor film in contact with it. It is also possible to determine whether or not oxygen has been added to the insulating film.

[0144] Thus, the introduction of oxygen 145 forms an oxygen-rich first insulating film 114a. By using an oxygen-rich first insulating film 114a, the thermal treatment during the transistor fabrication process is improved. Due to solid-phase diffusion caused by the principle, it is possible to supply oxygen to the oxide semiconductor film 108. Furthermore, by introducing oxygen 145, the oxide semiconductor is separated via the first insulating film 114a. Oxygen may be introduced into membrane 108.

[0145] Next, a second insulating film 114b is formed on the first insulating film 114a (see Figure 4(D)). .

[0146] The second insulating film 114b is formed by plasma CVD and sputtering. It is possible to produce silicon oxide films, gallium oxide films, aluminum oxide films, silicon nitride films, Using a silicon oxide nitride film, an aluminum oxide nitride film, or a silicon nitride film This is possible. The thickness of the second insulating film 114b is preferably 50 nm or more and 500 nm or less. It's nice.

[0147] In this embodiment, the second insulating film 114b is processed by plasma CVD at 370 nm A silicon oxide nitride film is formed. The deposition conditions for the second insulating film 114b are, for example, SiH The gas flow rate ratio of 4 and N2O is set to SiH4:N2O = 30 sccm:4000 sccm, and the pressure The force is set to 200 Pa, the RF power supply power (power output) to 150 W, and the substrate temperature to 220°C ± 15℃ would be appropriate.

[0148] Furthermore, when the first insulating film 114a and the second insulating film 114b are formed from the same type of material... The interface between the first insulating film 114a and the second insulating film 114b may not be clearly defined. Therefore, in this embodiment, the first insulating film 114a and the second insulating film 114b The interface is shown by a dashed line.

[0149] Furthermore, the second insulating film 114b, like the first insulating film 114a, contains as much water, hydrogen, etc. as possible. It is preferable that the film does not contain impurities. Therefore, in this embodiment, after film formation, The second insulating film 114b is subjected to a heat treatment (dehydration or dehydration) for the purpose of removing hydrogen atoms. Perform a basic processing step.

[0150] The heat treatment temperature is, for example, 250°C to 600°C, preferably 300°C to 600°C. The temperature can be below ℃. In this embodiment, heat treatment is performed at 350℃ for 1 hour.

[0151] Next, an aluminum film 115 is formed on the second insulating film 114b (see Figure 5(A)). .

[0152] The aluminum film 115 is formed by sputtering, vapor deposition, CVD, etc. This is preferable. Furthermore, the thickness of the aluminum film 115 should be between 3 nm and 10 nm. This is preferable. In this embodiment, a sputtering method is used to create an aluminum film with a thickness of 5 nm. It forms a film.

[0153] Furthermore, the aluminum film 115 formed on the second insulating film 114b is later subjected to oxygen introduction treatment. Through processing, it becomes an aluminum oxide film, which then serves as a barrier film for transistors. It is a film that can do this. The aluminum oxide film prevents impurities such as hydrogen and water from entering the transistor, and The membrane has a high barrier effect (blocking effect) that prevents both oxygen and nitrile from passing through, i.e., barrier It has the characteristic of being a.

[0154] Next, oxygen 147 is introduced into the aluminum film 115. The um film 115 becomes the aluminum oxide film 116 (see Figure 5(B)).

[0155] Oxygen 147 can be introduced using the same method as oxygen 145.

[0156] Furthermore, the introduction of oxygen 147 allows the second insulating film 114b to form via the aluminum film 115. Oxygen may be introduced into a portion of the film. This allows the second insulating film 114b to be the same as the previous film. This method replenishes oxygen that may be lost during heat treatment, and also improves oxygen content compared to stoichiometric composition. It is possible to form regions containing an excess of [the substance]. Furthermore, acids exceeding such stoichiometric compositions can form. The region containing the element only needs to be present in a part of the second insulating film 114b. The depth can be controlled as appropriate depending on the injection conditions.

[0157] Furthermore, in the aluminum oxide film 116, there is a region containing oxygen exceeding the stoichiometric composition. It may be formed. However, the aluminum oxide film 116 formed by the oxygen introduction treatment is It is not necessary to contain oxygen in a stoichiometric composition, and it may have some conductivity. For example, if the composition is Al2O x In the case of an aluminum oxide film represented by [formula], x is between 1 and 3.5. It is preferable to have it as shown below. Also, if the aluminum oxide film 116 is conductive, The resistivity ρ is 10 10 Ω m or more 10 19 Ω·m or less, preferably 10 10 Ω m or more 1 0 18 Ω·m or less, more preferably 10 11 Ω m or more 10 15 It should be less than or equal to Ω·m Preferably, the aluminum oxide film 116 has a resistivity within the above range, so the transient This makes it possible to prevent electrostatic discharge damage to the Ta150.

[0158] Furthermore, the aluminum oxide film 116 oxidizes the aluminum film 115. This is the film that is formed. By oxidation of the aluminum film 115, an aluminum oxide film 116 is formed. By forming this, compared to the case where an aluminum oxide film is deposited by sputtering, This can improve productivity.

[0159] Furthermore, after introducing oxygen 147 into the aluminum film 115, heat treatment may be performed. Heat treatment removes oxygen contained in the first insulating film 114a or the second insulating film 114b. It may also be supplied to the oxide semiconductor film 108 to replenish the oxygen vacancies in the oxide semiconductor film 108. The heat treatment temperature is, for example, 250°C to 600°C, preferably 300°C to 600°C. The following can be done. In this embodiment, heat treatment is performed at 300°C for 1 hour.

[0160] Next, a planarizing insulating film 118 is formed on the aluminum oxide film 116 (see Figure 5(C)). ).

[0161] The planarizing insulating film 118 only needs to be able to flatten the irregularities of the transistor 150, for example For example, polyimide resins, acrylic resins, polyimidoamide resins, benzocyclobutene Using heat-resistant organic materials such as polyamide resins and epoxy resins is possible. Yes, it is possible. In addition to the organic materials mentioned above, low dielectric constant materials (low-k materials) and siloxane-based resins can also be used. Oils and the like can be used. Furthermore, multiple insulating films formed from these materials can be stacked. The planar insulating film 118 may be formed by the same method. In this embodiment, the planar insulating film 118 is formed as Therefore, a 1.5 μm acrylic resin is used.

[0162] As described above, the transistor 150 shown in this embodiment has an oxide in the channel formation region. A semiconductor film is used, and copper, a low-resistance material, is used for the gate electrode, source electrode, and drain electrode. Furthermore, backcharging of the oxide semiconductor film occurs during the formation of the source electrode and drain electrode. Since the flannel side does not come into contact with the copper film, there is no risk of it adhering to or diffusing onto the oxide semiconductor film. It is possible to suppress certain copper elements. Also, the gate electrode, source electrode, and drain electrode. Each of these uses a copper film and has a barrier metal that can suppress the diffusion of copper elements. Therefore, it has stable electrical characteristics and low signal delay due to wiring resistance. We can provide the service.

[0163] The configurations and methods described in this embodiment are similar to those described in other embodiments. They can be used in combination as appropriate.

[0164] (Embodiment 2) In this embodiment, a modified example of the semiconductor device shown in Embodiment 1, and the same as shown in Embodiment 1 A different method for fabricating the semiconductor device described above will be explained using Figures 6 to 8. Note that the same symbols are used for the same symbols shown in Figures 1 to 5, and their repetition is explained below. (This part is omitted.)

[0165] <Example of semiconductor device configuration 2> Figure 6 shows an example configuration of transistor 250 and signal line region 260. Figure 6(A) shows Figure 6(B) is a plan view of the transistor 250 and the signal line area 260, and Figure 6(B) is a plan view of Figure 6(A). This is a cross-sectional view along X2-Y2. Note that in Figure 6(A), to avoid complexity, Transistor 250 and some of the components of the signal line region 260 (for example, gate insulating film 2 06, the second metal film 210b, etc., are omitted from the illustration.

[0166] The semiconductor device shown in Figure 6 has a gate electrode 204 formed on a substrate 102, and a gate electrode A gate insulating film 206 formed on 204, and a gate electrode 2 in contact with the gate insulating film 206 An oxide semiconductor film 108 formed in a position overlapping with 04, and a shape formed on the oxide semiconductor film 108 The formed source electrode 210 and drain electrode 212 are electrically connected to the source electrode 210. It has a signal line 232, and the signal line 232 has a first metal film 210a and a second metal film It consists of a 210b and a third metal film 210c, the second metal film 210b being the first metal film Formed in the region inside the edges of 210a and the third metal film 210c, source electrode 21 The 0 and drain electrode 212 are made of a first metal film 210a, a first metal film 212a, and a third metal It is composed of a metal film 210c and the third metal film 212c.

[0167] Furthermore, the gate electrode 204 is connected to the first gate electrode 204a and the second gate electrode 204b. It is composed of the following. The first gate electrode 204a is made of tungsten, tantalum, titanium, Using a metal film or metal nitride film containing one or more elements selected from molybdenum It is preferable that the second gate electrode 204b contains copper. For example, In this embodiment, a tungsten film is used as the first gate electrode 204a, A copper film is used as the gate electrode 204b of 2. A gate electrode 204 with such a layered structure and This makes it possible to have a low-resistance gate electrode 204. Note that the first gate electrode 2 By providing 04a, the substrate 102 and the copper film used as the second gate electrode 204b are Copper in the copper film used to improve adhesion and / or as a second gate electrode 204b It can suppress the diffusion of elements.

[0168] Furthermore, the gate insulating film 206 consists of a first gate insulating film 206a and a second gate insulating film 20 It is composed of 6b. The first gate insulating film 206a is the second gate electrode 204b It is sufficient that the silicon nitride film has the function of suppressing the diffusion of copper elements in the copper film used as such. Using silicon nitride film, aluminum oxide film, aluminum nitride film, etc. This can be achieved. In addition, the second gate insulating film 206b is formed later by the oxide semiconductor film 108 It is sufficient if it has the function of supplying oxygen, such as silicon oxide film, silicon oxide nitride film, etc. It can be used. For example, in this embodiment, the first gate insulating film 206a and Then, using a silicon nitride film, a silicon oxide nitride film is used as the second gate insulating film 206b. This is used. By using such a layered structure for the gate insulating film 206, the gate electrode 204 and This suppresses the diffusion of copper elements in the copper film used, and also in the oxide semiconductor film 108 that is formed later. It can supply oxygen.

[0169] Furthermore, the first metal film 210a, the first metal film 212a, the third metal film 210c, and As for the metal film 212c of 3, among tungsten, tantalum, titanium, and molybdenum... It is preferable to use a metal film or metal nitride film containing one or more elements selected from the above.

[0170] For example, in this embodiment, the first metal film 210a and the first metal film 212a and For example, using a tungsten film, the third metal film 210c and the third metal film 212c are used. This uses a tantalum nitride film.

[0171] Furthermore, the second metal film 210b preferably contains copper. Therefore, a copper film is used as the second metal film 210b.

[0172] Thus, the source electrode 210 and drain electrode 212 used in the transistor 250 The configuration and the configuration of the signal line 232 are different. The source electrode 210 and the drain electrode 212 are made of copper. By electrically connecting the signal line 232, which uses a film structure, signal delay caused by wiring resistance is reduced. This can suppress the following. Also, the source electrode 210 and the do used in the transistor 250 By not using a material containing copper elements in the rain electrode 212, the oxide semiconductor film 10 It is effective because it allows copper elements that might diffuse into area 8 to be placed at a distance. The signal line 232, source electrode 210, and drain electrode 212 are used in the same semiconductor manufacturing process. Because it can be manufactured using this method, it offers excellent benefits such as reducing manufacturing costs.

[0173] Next, using Figures 7 and 8, we will examine the transistor 250 and signal line region 260 shown in Figure 6. We will explain how to manufacture it.

[0174] <Method for fabricating semiconductor devices 2> First, a gate electrode 204, a gate insulating film 206, and an oxide semiconductor film 1 are placed on the substrate 102. Form 08. Note that gate electrode 204, gate insulating film 206, and oxide semiconductor film 1 Regarding 08, by referring to the steps shown in Figures 2(A) to 2(D) of Embodiment 1, , can be formed. Subsequently, on the gate insulating film 206 and the oxide semiconductor film 108 , source electrode and drain electrode, and a first metal film 209a that serves as a signal line, and a second A metal film 209b is formed (see Figure 7(A)).

[0175] The first metal film 209a is tungsten, tantalum, titanium, and molybdenum. Preferably, it is a metal film or metal nitride film containing one or more elements selected from among them. In this embodiment, the first metal film 209a is formed using a sputtering method. A tungsten film with a thickness of 50 nm is used.

[0176] Furthermore, the first metal film 209a may be in a laminated structure. For example, the first metal film 209a The first layer is selected from tungsten, tantalum, titanium, and molybdenum. A metal film containing one or more elements, and as the second layer of the first metal film 209a, tungsten nitride One or more elements selected from tantal nitride, titanium nitride, and molybdenum nitride Examples include a layered structure containing metal nitride films.

[0177] The first metal film 209a is in contact with the oxide semiconductor film 108, therefore the oxide semiconductor film 108 A material that does not undergo n-type conversion by extracting oxygen from it, or a material that diffuses into the oxide semiconductor film 108 and undergoes n-type conversion. A material that does not allow this is used. Also, the first metal film 209a is used for the second metal film 209b. It is desirable to use a material that suppresses the diffusion of copper elements from the copper film to the oxide semiconductor film 108.

[0178] The second metal film 209b is preferably a film containing the element copper. Copper alloys containing several weight percent of elements such as nium, gold, silver, zinc, tin, and nickel may also be used. In this embodiment, the second metal film 209b is formed using the sputtering method. A copper film with a thickness of 200 nm is used.

[0179] Next, a resist is applied to the second metal film 209b, and the first patterning is performed, and the resist is applied. Form the stomach mask 241 (see Figure 7(B)).

[0180] The resist mask 241 is made of the same material as the resist mask 141 shown in Embodiment 1. It can be formed by the and methods.

[0181] Next, a portion of the second metal film 209b is removed by the first etching, and the second metal film 2 Forms 10b (see Figure 7(C)).

[0182] As a method for removing the second metal film 209b, a wet etching method is preferable. Furthermore, the chemical solution used in the wet etching method is the etching solution for the second metal film 209b. Any chemical solution that can be used that does not cause the first metal film 209a to disappear is acceptable, for example, the first A tungsten film is used as the first metal film 209a, and a copper film is used as the second metal film 209b. If used, the chemical solution should be a mixture of water, hydrogen peroxide, and carboxylic acid, or water, phosphoric acid, and nitric acid. A mixture of sulfuric acid and potassium sulfate can be used.

[0183] Furthermore, by adjusting the wet etching time and performing isotropic etching, the resist mass is formed. The side surface of the second metal film 210b may be set back inward from the side surface of the ku 241. .

[0184] Thus, during the first etching, in the signal line region 260, the second metal film 2 In the region where 09b remains and the oxide semiconductor film 108 is formed, a second metal film 209 Remove b.

[0185] Next, the resist mask 241 is removed, and the first metal film 209a and the second metal film 21 A third metal film 209c is formed on 0b (see Figure 7(D)).

[0186] As a method for removing the resist mask 241, the resist mask 141 shown in Embodiment 1 This can be done using a method similar to the removal method for [previous method].

[0187] The third metal film 209c is prepared using the same method and materials as the first metal film 209a. It can be formed. In this embodiment, the third metal film 209c is A tantalum nitride film with a thickness of 100 nm, formed using the sputtering method, is used.

[0188] Next, a resist is applied to the third metal film 209c, and the second patterning is performed, and the resist is applied. Form the stomach mask 242 (see Figure 8(A)).

[0189] The resist mask 242 is formed using the same materials and methods as the resist mask 241. It is possible.

[0190] Next, portions of the first metal film 209a and the third metal film 209c are subjected to the second etching process. Further removal of the first metal film 210a, the first metal film 212a, the third metal film 210c, and Then a third metal film 212c is formed (see Figure 8(B)).

[0191] Furthermore, the second etching is performed on the second metal film 210b that was removed by the first etching. The first metal film 209a and the third metal film 209c are removed outside the end of the film.

[0192] As a method for removing the first metal film 209a and the third metal film 209c, dry etching is used. The etching method is preferable. Examples of gases used in the dry etching method include the first A tungsten film is used as the metal film 209a, and a tungsten nitride film is used as the third metal film 209c. When using a talus membrane, a mixed gas of SF6 and O2, or a mixed gas of SF6 and BCl3, etc. It can be used.

[0193] Furthermore, during etching of the first metal film 209a and the third metal film 209c, The etching conditions are optimized so that the semiconductor film 108 is not etched and fragmented. It is desirable that the first metal film 209a and the third metal film 209c are used. To etch the oxide semiconductor film 108 without etching it at all is to obtain the condition that It is difficult, and oxide semiconductors are difficult to etch during the etching of the first metal film 209a and the third metal film 209c. The conductive film 108 is an oxide semiconductor film 108 which is partially etched and has grooves (recesses) It can happen.

[0194] Next, the resist mask 242 is removed, and the first metal film 210a and the third metal film 21 A source electrode 210 made of 0c, a first metal film 212a, and a third metal film 212c A drain electrode 212 is formed. In addition, in the signal line region 260, the first gold Signal line 232 consisting of a metal film 210a, a second metal film 210b, and a third metal film 210c A structure is formed (see Figure 8(C)).

[0195] Thus, the signal line 232 uses a copper film as the second metal film 210b, and the second metal film Source electrode 210 and drain electrode 212 without using 210b are manufactured in the same process. It is possible.

[0196] The method for removing resist mask 242 is the same as the method for removing resist mask 241. This can be done using the appropriate method.

[0197] Furthermore, after the formation of the signal line 232, source electrode 210, and drain electrode 212, the oxide semiconductor It is preferable to clean the conductive film 108 (more specifically, the back channel side). For cleaning the conductive film 108, for example, oxygen plasma treatment or dilute hydrofluoric acid treatment may be used. Cleaning treatments such as this are effective. By performing such cleaning, the source electrode 2 10, and the etching gas components used when forming the drain electrode 212, or resist The residue of sucrose 242 can be removed from the oxide semiconductor film 108, and the oxide semiconductor film 1 It is possible to make 08 even more pure.

[0198] Furthermore, after the formation of the signal line 232, source electrode 210, and drain electrode 212, heat treatment is performed. It may be performed. The temperature of the heat treatment should be 250°C or higher and 650°C or lower, preferably 450°C or lower. The temperature should be 600°C or lower, or below the strain point of the substrate.

[0199] Through the above process, the transistor 250 and signal line region 260 shown in this embodiment A formation is created.

[0200] Next, the transistor 250 and the signal line region 260 are covered with a first insulating film 114a and a second An insulating film 114b, an aluminum oxide film 116, and a planar insulating film 118 are formed (Figure 8). (See (D)).

[0201] First insulating film 114a, second insulating film 114b, aluminum oxide film 116, and flat The insulating film 118 can be formed by referring to the process shown in Embodiment 1. Cut.

[0202] Thus, the configuration of the source electrode 210 and drain electrode 212 of the transistor 250 and The configuration of the signal line 232 in the signal line region 260 is different. Source electrode 210 and drain electrode By electrically connecting the signal line 232, which uses a copper film, to 212, the signal caused by wiring resistance is reduced. It is possible to suppress the number delay, etc. Also, the source electrode 210 used in transistor 250 Furthermore, by not using a material containing copper elements for the drain electrode 212, the oxide semiconductor This method is effective because it allows copper elements that might diffuse into film 108 to be positioned at a distance. Furthermore, the signal line 232, source electrode 210, and drain electrode 212 are also used in the semiconductor manufacturing process. Because it can be manufactured in a single process, it offers excellent benefits such as reducing manufacturing costs. ru.

[0203] The configurations and methods described in this embodiment are similar to those described in other embodiments. They can be used in combination as appropriate.

[0204] (Embodiment 3) A display using the transistor or signal line exemplified in Embodiment 1 and Embodiment 2 A display device with the ability to do so can be manufactured. Also, a part of the drive circuit including a transistor can be manufactured. Alternatively, the entire system can be integrally formed on the same substrate as the pixel section to form a system-on-panel. Yes, it is possible. An example of a display device will be explained using Figure 9.

[0205] In Figure 9, the pixel section 302 provided on the first substrate 300 and the source driver circuit A sealing material 312 is provided so as to surround section 304 and the gate driver circuit section 306. It is also composed of a pixel section 302, a source driver circuit section 304, and a gate driver circuit. A second substrate 301 is provided on the path section 306. Therefore, the pixel section 302 and the sourced The driver circuit section 304 and the gate driver circuit section 306 are connected to the first substrate 300 and a sealing material The display element is sealed together with 312 and the second substrate 301.

[0206] Furthermore, in Figure 9, the area surrounded by the sealing material 312 on the first substrate 300 In a region different from the area, there is a pixel unit 302, a source driver circuit unit 304, and a gate driver. FPC terminal section 308 (FPC: Flexible) is electrically connected to circuit section 306. A printed circuit is provided, and the FPC terminal section 308 has an FP C316 is connected to the pixel unit 302, source driver circuit unit 304, and gate driver. The various signals and potentials supplied to the circuit section 306 are provided by the FPC 316.

[0207] Furthermore, in Figure 9, the pixel section 302, the source driver circuit section 304, and the gate driver circuit are shown. Signal lines 310 are connected to the path section 306 and the FPC terminal section 308, respectively. The various signals and potentials supplied by 316 are transmitted to the pixel unit 302 via the signal line 310. Source driver circuit section 304, gate driver circuit section 306, and FPC terminal section 308 It is given.

[0208] Furthermore, in Figure 9, the source driver circuit section 304 and the gate driver circuit section 30 The example shown has 6 formed on the same first substrate 300 as the pixel portion 302, but in this configuration... Not limited to this. For example, only the gate driver circuit section 306 may be formed on the first substrate 300. Alternatively, the source driver circuit section 304 may be formed on the first substrate 300. In this case, a separate source driver circuit or gate driver circuit is formed on the base. A plate (for example, a drive circuit substrate formed from a single-crystal semiconductor film or a polycrystalline semiconductor film) is placed on a first base This configuration, implemented on board 300, is also a good option.

[0209] Furthermore, the method of connecting the separately formed drive circuit board is not particularly limited, COG (Chip On Glass) method, wire bonding method, or TAB (Tap Methods such as automated bonding can be used.

[0210] Furthermore, the display device includes a panel in which the display elements are sealed, and a control on the panel This includes modules that have ICs, etc., mounted on them, including those containing R.

[0211] In this specification, the term "display device" refers to an image display device, a display device, or This refers to light sources (including lighting devices). It also includes connectors, such as FPC or TAB tapes. Alternatively, a module with a TCP (Tape Carrier Package) attached. A module or display element with a printed circuit board attached to the end of a TAB tape or TCP. This also displays all modules where the drive circuit board or IC is directly mounted using the COG method. It shall be included in the device.

[0212] Furthermore, the pixel section 302 and source driver circuit section 304 are provided on the first substrate 300. The gate driver circuit section 306 has multiple transistors, and the embodiment 1 and The transistor exemplified in Embodiment 2 can also be applied. Next, we will explain the case where the transistor exemplified in Embodiment 2 is applied.

[0213] Furthermore, the display elements provided in the display device include liquid crystal elements (also called liquid crystal display elements) and A light-emitting element (also called a light-emitting display element) can be used. The light-emitting element can be powered by current or voltage This category includes elements whose brightness is controlled by [a specific mechanism], specifically inorganic EL (Elec). This includes luminescence, organic EL, etc. Also, electronic ink, etc. Display media in which the contrast changes due to electrical effects can also be applied.

[0214] One form of a display element provided in a display device will be explained using Figures 10 and 11. The display devices shown in Figures 10 and 11 correspond to the cross-sectional view in the dashed line QR shown in Figure 9. do.

[0215] The display device shown in Figure 10 has an FPC terminal section 308 provided on the first substrate 300, Terminal electric field consisting of a first metal film 360a, a second metal film 360b, and a third metal film 360c It has poles 360, and the terminal electrodes 360 are anisotropic conductive film 38 of the terminals of the FPC 316. It is electrically connected via 0.

[0216] The terminal electrode 360 ​​is the source electrode of transistor 350 and transistor 352, and It is formed using the same process as the drain electrode and the same process as the signal line 310.

[0217] Furthermore, the pixel section 302 and source driver circuit section 304 are provided on the first substrate 300. It has multiple transistors, and in Figures 10 and 11, it is included in the pixel section 302. Transistor 350 and transistor 352 included in source driver circuit section 304 This is an example.

[0218] In this embodiment, the transistor 350 included in the pixel section 302 and the saw The transistor 352 included in the driver circuit section 304 is configured to be of the same size. However, it is not limited to this. The transistors used can be adjusted as needed, by changing their size (L / W) or the number of transistors used. This is possible. Also, in Figures 10 and 11, the gate driver circuit section 306 is Although not shown in the diagram, the source driver circuit section 304 differs in connection destination or connection method, etc. A similar configuration can be adopted.

[0219] Furthermore, in Figures 10 and 11, transistor 350 and transistor 352, Furthermore, signal line 310 is connected to the transistor 250 and signal line 23 shown in the previous embodiment 2. It can be configured similarly to option 2.

[0220] That is, in transistors 350 and 352, the first metal film and It has a source electrode and a drain electrode made of a third metal film, and in the signal line 310, It has wiring consisting of a first metal film, a second metal film, and a third metal film. The metal film is selected from tungsten, tantalum, titanium, and molybdenum. The first metal film is a metal film or metal nitride film containing the above elements, and the second metal film is a material containing the element copper. It is formed by [this].

[0221] Furthermore, the terminal electrode 360 ​​has the same configuration as the signal line 310, and the first metal film and It is composed of a second metal film and a third metal film.

[0222] Thus, in transistors 350 and 352, copper film is not used. The source electrode and drain electrode are configured in a certain way, along with the signal line 310 and terminal electrode. In transistor 360, it is made of a copper film. Transistor 350, and transistor By using 352, as well as the signal line 310 and the terminal electrode 360, a stable electrical A display device can be provided that has electrodes or wiring with specific characteristics and low resistance.

[0223] Furthermore, in Figures 10 and 11, on transistors 350 and 352 An insulating film 364, a protective insulating film 366, and a planarizing insulating film 368 are provided.

[0224] In this embodiment, a silicon oxide nitride film is used as the insulating film 364, and the protective insulating film 3 For 66, an aluminum oxide film is used. Note that insulating film 364 and protective insulating film 36 6 can be formed by sputtering or plasma CVD.

[0225] The silicon oxidnitride film provided as the insulating film 364 is provided in contact with the oxide semiconductor film. This allows oxygen to be supplied to the oxide semiconductor film.

[0226] The aluminum oxide film provided as the protective insulating film 366 is protected from impurities such as hydrogen and water, and It has a high barrier effect (blocking effect) that prevents both oxygen and oxidative stress from passing through the membrane. Aluminum films are susceptible to fluctuations in quality during and after the manufacturing process, such as the presence of hydrogen and water. The impurity of substances into oxide semiconductor films, and the acidity of oxygen, which is a major component material constituting oxide semiconductor films. It functions as a protective film that prevents emission from the ion semiconductor film.

[0227] Furthermore, the planarizing insulating film 368 may be a polyimide resin, an acrylic resin, or a polyimide resin. Heat-resistant resins such as amide resins, benzocyclobutene resins, polyamide resins, and epoxy resins. Organic materials having properties can be used. Furthermore, insulating films formed from these materials can be combined. A planar insulating film 368 may be formed by stacking several layers.

[0228] Furthermore, the display device shown in this embodiment has a trace formed in the source driver circuit section 304. A planarizing insulating film 368 is provided on the radiator 352, and an oxide film is applied to the planarizing insulating film 368. The conductive film 370a is provided in a position superimposed on the channel formation region of the semiconductor film. Yes, it exists. However, it is not limited to this configuration, and a configuration without the conductive film 370a is also possible. By placing the film 370a in a position that overlaps with the channel formation region of the oxide semiconductor film, This reduces the change in the threshold voltage of transistor 352 before and after the BT test. Also, the conductive film 370a may have the same potential as the gate electrode of transistor 352. Furthermore, they can be different, and can also function as a second gate electrode. The potential of film 370a may be GND, 0V, or in a floating state.

[0229] Furthermore, the conductive film 370a shields the external electric field, that is, the external electric field does not penetrate the internal (transistor) Functions to prevent the circuit section (including ZISTA 352) from being affected (especially electrostatic shielding against static electricity) It also has the function of shielding the conductive film 370a, which protects against the influence of external electric fields such as static electricity. This prevents fluctuations in the electrical characteristics of transistor 352. The film 370a may be provided over a wide area so as to overlap with the transistor 352. Further improvements in electrostatic shielding capabilities are expected.

[0230] Furthermore, the display device shown in this embodiment has a transistor 350 formed in the pixel section 302 A planarizing insulating film 368 is provided on top, and a source electrode or a dot is placed on the planarizing insulating film 368. The configuration includes a conductive film 370b that connects to the rain electrode. The conductive film 370b is a pixel In section 302, it functions as a pixel electrode.

[0231] The transistor 350 provided in the pixel section 302 is electrically connected to the display element and displays The panel is constructed using various display elements, as long as they can perform a display. You can use it.

[0232] The display device shown in Figure 10 is an example of a liquid crystal display device that uses liquid crystal elements as display elements. In Figure 10, the liquid crystal element 402, which is a display element, has a conductive film 370b, a counter electrode 404, and includes a liquid crystal layer 406. Furthermore, an insulating film that functions as an alignment film is provided to sandwich the liquid crystal layer 406. An edge film 410 and an insulating film 412 are provided. The counter electrode 404 is on the second substrate 301 side. The conductive film 370b and the counter electrode 404 are stacked via a liquid crystal layer 406. It is.

[0233] Furthermore, the spacer 435 is a columnar space obtained by selectively etching the insulating film. It is a control element and is provided to control the film thickness (cell gap) of the liquid crystal layer 406. Oh, you can also use spherical spacers.

[0234] When using liquid crystal elements as display elements, thermotropic liquid crystals, low molecular weight liquid crystals, and polymer liquid crystals are used. Liquid crystals, polymer-dispersed liquid crystals, ferroelectric liquid crystals, antiferroelectric liquid crystals, etc. can be used. These liquid crystal materials, depending on the conditions, can be classified into cholesteric phase, smectic phase, cubic phase, and It exhibits iralnematic phase, isotropic phase, etc.

[0235] Furthermore, when employing a transverse electric field method, it is also possible to use a liquid crystal that exhibits a blue phase without using an alignment layer. The blue phase is one of the liquid crystal phases, and as the temperature of cholesteric liquid crystal is increased, the cholesteric phase This phase appears just before the transition from the blue phase to the isotropic phase. The blue phase only appears within a narrow temperature range. To improve the temperature range, a liquid crystal assembly containing several weight percent or more of chiral agent was mixed in. The resulting material is used in the liquid crystal layer. The liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent provides a fast response. Because the angle is short and optically isotropic, orientation processing is unnecessary, and the field of view dependence is small. Since an orientation film does not need to be applied, rubbing treatment is also unnecessary, and therefore the rubbing treatment does not affect the material. This prevents electrostatic discharge damage that can occur, and reduces defects and damage to liquid crystal displays during the manufacturing process. This can be mitigated. Therefore, it becomes possible to improve the productivity of liquid crystal display devices. Transistors using semiconductor films are affected by static electricity, which affects the electrical characteristics of the transistor. The voltage may fluctuate significantly and deviate from the design range. Therefore, transistors using oxide semiconductor films may be used. Using a blue-phase liquid crystal material in a liquid crystal display device with a zista is more effective.

[0236] Furthermore, the resistivity of the liquid crystal material is 1 × 10⁻⁶ 9 The value is Ω·cm or greater, preferably 1 × 10⁻⁶. 1 1 It is Ω·cm or greater, and more preferably 1 × 10⁻⁶ 12 It is greater than Ω·cm. The resistivity values ​​in the detailed specifications shall be those measured at 20°C.

[0237] The size of the retention capacitance provided in a liquid crystal display device depends on the number of transistors arranged in the pixel area. The charging capacity is set to hold the charge for a predetermined period, taking into account the current and other factors. The size should be set considering the transistor's off-current, etc. High purity and oxygen-deficient By using a transistor having an oxide semiconductor film whose formation is suppressed, A holding capacity having a capacity of 1 / 3 or less, preferably 1 / 5 or less, of the liquid crystal capacity. Providing that would be sufficient.

[0238] The oxide semiconductor film used in this embodiment has been purified to suppress the formation of oxygen vacancies. Transistors can have a low current value in the off state (off current value). This allows for longer retention times of electrical signals such as image signals, and writing is possible when the power is on. The interval can also be set to be long. Therefore, the frequency of refresh operations can be reduced. This has the effect of reducing power consumption.

[0239] Furthermore, the highly purified oxide semiconductor film used in this embodiment, which suppresses the formation of oxygen vacancies, The transistors possessing this feature can achieve relatively high field-effect mobility, enabling high-speed operation. For example, by using such high-speed drive transistors in a liquid crystal display device, The switching transistors in the pixel section and the driver transistors used in the drive circuit section are the same. It can be formed on a single substrate. That is, a separate drive circuit is used on a silicon wafer or the like. Since it is not necessary to use pre-formed semiconductor devices, the number of components in the semiconductor device can be reduced. This is possible. Furthermore, by using transistors capable of high-speed driving in the pixel section, We can provide high-quality images.

[0240] Furthermore, the switching transistors in the pixel section and the driver transistors used in the drive circuit section. The signal lines connected to the zista use wiring containing copper elements. Therefore, the wiring resistance is This results in less signal delay and other interference, making it suitable for use in large-screen display devices.

[0241] LCD displays include TN (Twisted Nematic) mode and IPS (In- Plane-Switching) mode, FFS (Fringe Field Switching) tching) mode, ASM(Axially Symmetric aligned) Micro-cell) mode, OCB(Optical Compensated) Birefringence mode, FLC (Ferroelectric Liqu id Crystal) mode, AFLC (AntiFerroelectric Li) You can use modes such as Quid Crystal.

[0242] Furthermore, normally black liquid crystal display devices, such as those employing vertical alignment (VA) mode, are also available. It may also be used as a transmissive liquid crystal display device. Several vertical orientation modes are possible, For example, MVA (Multi-Domain Vertical Alignment) Mode, PVA (Patterned Vertical Alignment) mode These can be used. It can also be applied to VA-type liquid crystal display devices. A type A liquid crystal display device is a type of method that controls the arrangement of liquid crystal molecules in a liquid crystal display panel. In VA-type liquid crystal display devices, when no voltage is applied, liquid crystal molecules are present on the panel surface. This method is oriented vertically. Furthermore, pixels are divided into several subpixel regions. This involves dividing the molecule into parts and devising a method to tilt each part in a different direction, known as multi-domainization or multi- A method called multi-domain design can be used.

[0243] Furthermore, in a display device, a black matrix (light-shielding layer), a polarizing member, a phase difference member, and a reverse Optical components (optical substrates) such as anti-radiation members shall be provided as appropriate. For example, polarizing substrates and phase difference Circular polarization using a substrate may also be used. Furthermore, backlights, sidelights, etc., may be used as light sources. You may use it.

[0244] Furthermore, the display method used in the pixel area may be a progressive or interlaced method. It is possible to do so. Also, the color elements controlled by pixels when displaying color include RGB(R It is not limited to the three colors (where G represents red, G represents green, and B represents blue). For example, RGBW (where W represents white). ), or RGB with one or more additional colors such as yellow, cyan, and magenta. The size of the display area may differ for each dot of the color element. However, the disclosed This is not limited to color display devices, but also applies to monochrome display devices. It is also possible to do so.

[0245] Furthermore, the display element included in the display device utilizes light emission that employs electroluminescence. Elements can be applied. Light-emitting devices that utilize electroluminescence are light-emitting materials They are distinguished by whether the substance is an organic compound or an inorganic compound; generally, the former is organic EL elements, and the latter are called inorganic EL elements.

[0246] Organic EL elements emit electrons and positive voltages from a pair of electrodes when a voltage is applied to the light-emitting element. Each pore is injected into a layer containing a luminescent organic compound, and an electric current flows through it. The recombination of carriers (electrons and holes) causes the luminescent organic compound to form an excited state. It then emits light when the excited state returns to the ground state. From this mechanism, These light-emitting elements are called current-excited light-emitting elements.

[0247] Inorganic EL elements are classified into dispersed inorganic EL elements and thin-film inorganic EL elements depending on their element configuration. It is classified as follows: Dispersed inorganic EL elements have a light-emitting layer in which particles of light-emitting material are dispersed in a binder. It possesses a donor-acceptor level, and the luminescence mechanism utilizes donor-acceptor levels. This is acceptor-recombination type light emission. Thin-film inorganic EL elements sandwich the light-emitting layer between dielectric layers. Furthermore, it has a structure where it is sandwiched between electrodes, and the light emission mechanism involves the inner-shell electron transition of metal ions. The localized light emission method used is localized light emission. For this explanation, an organic EL element is used as the light-emitting element. do.

[0248] A light-emitting element only needs to have at least one of its pair of electrodes that is translucent in order to extract light. Then, transistors and light-emitting elements are formed on the substrate, and light is emitted from the side opposite to the substrate. This includes top-side emission, bottom-side emission which extracts light from the substrate side, and both the substrate side and the opposite side of the substrate. There are light-emitting elements with a double-sided emission structure that extract light from both sides, and any light-emitting element with an emission structure is applicable. It is possible.

[0249] Figure 11 shows an example of a display device using a light-emitting element as a display element. The sub-element 450 is electrically connected to the transistor 350 provided in the pixel section 302. The light-emitting element 450 is constructed by laminating a conductive film 370b, an electroluminescent layer 452, and an upper electrode 454. The structure is not limited to the configuration shown. The direction of light extracted from the light-emitting element 450 may vary. Additionally, the configuration of the light-emitting element 450 can be changed as appropriate.

[0250] The partition wall 456 is formed using an organic insulating material or an inorganic insulating material. In particular, partition wall 456 It is preferable to use a photosensitive resin material. For example, using the photosensitive resin material, partition wall When forming 456, a photosensitive resin material is placed on the planar insulating film 368 and the conductive film 370b. By applying the material and irradiating the desired area with light, an opening is formed on a portion of the conductive film 370b. The side walls of the opening can be formed to be inclined surfaces with a continuous curvature.

[0251] Even if the electroluminescent layer 452 consists of a single layer, it is configured to be stacked with multiple layers. It's fine either way.

[0252] To prevent oxygen, hydrogen, water, carbon dioxide, etc. from entering the light-emitting element 450, the upper electrode 454 , and a protective film may be formed on the partition wall 456. The protective film may be a silicon nitride film, a silicon nitride film A silicon oxide film and the like can be formed. Also, the first substrate 300 and the second substrate 301 And the space sealed by the sealing material 312 is provided with a filler material 458 and is sealed. Therefore, a protective film that is highly airtight and has minimal degassing is used to prevent exposure to the outside air. Packaging (enclosing) with adhesive film, UV-curing resin film, etc. or cover material. It is preferable to do so.

[0253] As for the filler 458, in addition to inert gases such as nitrogen and argon, UV-curing resin is also used. Alternatively, thermosetting resins can be used, such as PVC (polyvinyl chloride) and acrylic resins. Polyimide resins, epoxy resins, silicone resins, PVB (polyvinyl butyral resins) ) or EVA (ethylene vinyl acetate) can be used. For example, filler 45 For 8, nitrogen should be used.

[0254] Additionally, if necessary, a polarizing plate or circular polarizing plate (including elliptical polarizing plates) may be placed on the emission surface of the light-emitting element. ), phase difference plates (λ / 4 plate, λ / 2 plate), color filters, and other optical films are appropriately provided. Alternatively, an anti-reflective coating may be provided on the polarizing plate or circular polarizing plate. For example, on the surface irregularities. An anti-glare treatment can be applied to further diffuse reflected light and reduce glare.

[0255] In Figures 10 and 11, the first substrate 300 and the second substrate 301 are as follows: In addition to glass substrates, flexible substrates can also be used, such as translucent plastics. A plastic substrate such as a vinyl substrate can be used. As for plastics, FRP (Fiber Reinforced Plastic) can be used. Ass-Reinforced Plastics) board, PVF (Polyvinyl Fiber) (D) Film, polyester film, or acrylic resin film can be used. Also, a structure in which aluminum foil is sandwiched between PVF film or polyester film. You can also use the 'te' symbol.

[0256] As described above, the transistor or signal line shown in Embodiment 1 and Embodiment 2 By applying this technology, it is possible to provide a display device with various functions.

[0257] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. It is Noh.

[0258] (Embodiment 4) The semiconductor devices disclosed herein are applicable to a variety of electronic devices (including gaming machines). This can be done. As for electronic devices, for example, television equipment (television, or television) (Also called a receiver), computer monitors, e-paper, digital cameras, etc. Cameras such as digital video cameras, digital photo frames, mobile phones (mobile phones, mobile phones) (Also called a telephone device), portable game console, personal digital assistant (PDA), mobile terminal (smartphone) This includes phones, tablet PCs, etc., sound playback devices, and large game machines such as pachinko machines. Examples of electronic devices including semiconductor devices described in the above embodiment are shown in Figure 12. This will be explained using Figure 13.

[0259] Figure 12(A) shows a notebook-type personal computer, consisting of a main unit 3001 and a casing 30 It consists of 02, a display unit 3003, a keyboard 3004, etc. (Image of the above implementation) By applying the semiconductor device shown in any of the states to the display unit 3003, a stable electrical signal is obtained. A notebook-type personal computer that possesses certain characteristics and has low signal delay due to wiring resistance. It can be written as "ta".

[0260] Figure 12(B) shows a personal digital assistant (PDA), and the main unit 3021 has a display unit 3023 and An external interface 3025 and operation buttons 3024 are provided. A stylus 3022 is provided as an accessory for use. The semiconductor shown in any of the above embodiments. By applying the device to the display unit 3023, more stable electrical characteristics and wiring resistance are achieved. This allows for the creation of a personal digital assistant (PDA) with minimal signal delay caused by interference.

[0261] Figure 12(C) shows an example of an e-book. For example, the e-book 2700 has a casing 2 It consists of two enclosures, 701 and enclosure 2703. Enclosure 2701 and enclosure 27 03 is integrated with the shaft portion 2711, and the shaft portion 2711 is used as the axis for opening and closing operations. This configuration makes it possible to perform actions similar to those of a paper book. .

[0262] The display unit 2705 is incorporated into the housing 2701, and the display unit 2707 is incorporated into the housing 2703. It is included. Display units 2705 and 2707 are configured to display a continuation screen. Alternatively, a configuration that displays different screens is also acceptable. For example, text is displayed on the right-hand display unit (display unit 2705 in Figure 12(C)), and on the left-hand side... An image can be displayed on the display unit (display unit 2707 in Figure 12(C)). The semiconductor device shown in any of the above forms is to be applied to the display unit 2705 and the display unit 2707. This results in ebooks with stable electrical characteristics and minimal signal delay due to wiring resistance. This is possible. A semi-transmissive or reflective liquid crystal display device can be used as the display unit 2705. In this case, since it is expected to be used in relatively bright conditions, a solar panel will be installed, and the solar panel will It may be possible to generate electricity and charge it with a battery. The battery may be: Using lithium-ion batteries offers advantages such as miniaturization.

[0263] Furthermore, Figure 12(C) shows an example in which the housing 2701 is equipped with an operating section, etc. For example In the enclosure 2701, the power supply 2721, operation keys 2723, speaker 2725, etc. It is equipped with this feature. Pages can be turned using operation key 2723. Note that the display unit of the casing is the same as the display unit. The configuration may also include a keyboard and pointing device on one side. On the back or sides, there are external connection terminals (earphone terminal, USB terminal, etc.) and a recording medium insertion slot. It may also be configured to include such features. Furthermore, the eBook 2700 has the functionality of an electronic dictionary. It can also be a structured arrangement.

[0264] Furthermore, the e-book 2700 may be configured to transmit and receive information wirelessly. The system will be configured to purchase and download desired book data from an e-book server. It is also possible.

[0265] Figure 12(D) shows a mobile phone, which consists of two housings, housing 2800 and housing 2801. The enclosure 2801 contains a display panel 2802, a speaker 2803, and a microphone. Phone 2804, pointing device 2806, camera lens 2807, external connection terminal It is equipped with components such as the sub-component 2808. In addition, the housing 2800 has a solar cell for charging mobile phones. It features a 2810 cell, an external memory slot 2811, and other components. The antenna is located on the chassis. It is built into the 801. The semiconductor device shown in any of the above embodiments is a display panel. By applying it to RU2802, it has stable electrical characteristics and reliability due to wiring resistance This allows for mobile phones with minimal signal delay.

[0266] Furthermore, the display panel 2802 is equipped with a touch panel, and Figure 12(D) shows video display. The multiple operation keys 2805 are shown with dotted lines. Note that the solar cell 2810 A boost circuit is also implemented to increase the applied voltage to the voltage required for each circuit.

[0267] The display panel 2802 changes its orientation as appropriate depending on the usage mode. Since the camera lens 2807 is mounted on the same plane as the 2802, video calls are possible. Yes. Speaker 2803 and microphone 2804 are not limited to voice calls, but also to video calls. It can record, play back, and more. Furthermore, the casings 2800 and 2801 slide apart. As shown in Figure 12(D), it can be changed from an unfolded state to an overlapping state, and can be used on a mobile phone. Suitable miniaturization is possible.

[0268] External connection terminal 2808 can be connected to various cables such as AC adapters and USB cables. It is capable of charging and data communication with personal computers, etc. By inserting a recording medium into the memory slot 2811, it is possible to store and move larger amounts of data. Cut.

[0269] Furthermore, in addition to the above functions, it is equipped with infrared communication functions, television reception functions, etc. That's good too.

[0270] Figure 12(E) shows a digital video camera, consisting of a main unit 3051 and a display unit (A) 3057. Eyepiece 3053, operation switch 3054, display unit (B) 3055, battery 3056 It is composed of the above. The semiconductor device shown in any of the above embodiments is the display unit ( By applying A)3057 and the display unit (B)3055, stable electrical characteristics are obtained. Furthermore, it is possible to create a digital video camera with minimal signal delay caused by wiring resistance.

[0271] Figure 12(F) shows an example of a television system. The television system 9600 is The display unit 9603 is incorporated into the housing 9601. The display unit 9603 displays images. It is possible to demonstrate this. Furthermore, here, the stand 9605 supports the housing 9601. The configuration shown is as follows. The semiconductor device shown in any of the above embodiments is the display unit 9603. By applying this, it has stable electrical characteristics and reduces signal delay caused by wiring resistance. It can be a television system without a television.

[0272] The television unit 9600 is operated using the control switches on the housing 9601, as well as a separate unit. This can be done using the remote control unit. Alternatively, the remote control unit can be connected to the remote control unit. The system may also be configured to include a display unit that shows the output information.

[0273] The television system 9600 will consist of a receiver, modem, and other components. This allows for the reception of regular television broadcasts, and furthermore, wired or wireless connections are available via the modem. By connecting to a communication network, one-way (sender to receiver) or two-way communication is possible. It is also possible to perform two-way information communication (between a sender and receiver, or between receivers, etc.). .

[0274] Figure 13 shows an example of a tablet device, and Figures 13(A) to 13(C) are: Figure 13(D) shows tablet device 5000, and Figure 13(D) shows tablet device 6000. Yes, they are.

[0275] In the tablet terminal 5000 shown in Figures 13(A) to 13(C), Figure 13(A Figure 13(B) shows a front view, Figure 13(B) shows a side view, and Figure 13(C) shows a rear view. Furthermore, the tablet terminal 6000 shown in Figure 13(D) is shown in a front view. .

[0276] The tablet terminal 5000 consists of a housing 5001, a display unit 5003, a power button 5005, Front camera 5007, rear camera 5009, first external connection terminal 5011, and second external It is composed of parts such as connection terminals 5013.

[0277] Furthermore, the display unit 5003 is integrated into the housing 5001 and can also be used as a touch panel. It is possible to do so. For example, by displaying an icon 5015 on the display unit 5003, It can perform tasks such as log management and schedule management. In addition, the enclosure 5001 has a correct The front camera 5007 is integrated into the front side, allowing it to capture video from the user's perspective. Furthermore, the housing 5001 has a rear camera 5009 built into the back side, and the user and It is possible to capture images from the opposite side. Additionally, the housing 5001 has a first external connection terminal 5 It is equipped with a first external connection terminal 5, and a second external connection terminal 5013, for example, the first external connection terminal 5 Audio is output to earphones, etc. via 011, and data is output via the second external connection terminal 5013. It can be moved, etc.

[0278] Next, the tablet terminal 6000 shown in Figure 13(D) consists of a first housing 6001 and a second Housing 6003, hinge 6005, first display unit 6007, second display unit 6009, power supply It consists of a button 6011, a first camera 6013, a second camera 6015, etc. .

[0279] Furthermore, the first display unit 6007 is incorporated into the first housing 6001, and the second display The unit 6009 is incorporated into the second housing 6003. The first display unit 6007, and The second display unit 6009 uses, for example, the first display unit 6007 as a display panel, and The display unit 6009 of unit 2 is a touch panel. The text displayed on the first display unit 6007 After confirming icon 6017, icon 6019 was displayed on the second display unit 6009, This refers to keyboard 6021 (actually the keyboard image displayed on the second display unit 6009) It can be used to select images or input text, etc. Of course, the first display unit One configuration involves 6007 being a touch panel and the second display unit 6009 being a display panel, Both the first display unit 6007 and the second display unit 6009 are configured as touch panels. That's fine.

[0280] Furthermore, the first housing 6001 and the second housing 6003 are connected by a hinge portion 6005. The first housing 6001 and the second housing 6003 can be opened and closed. By adopting such a configuration, when carrying the tablet terminal 6000, the first housing The first display unit 6007 incorporated into 6001 and the second housing 6003 incorporated into By combining the 2nd display unit 6009 and the 2nd display unit 6, the first display unit 6007 and the 2nd display unit 6 It is preferable because it can protect the surface of 009 (for example, a plastic substrate).

[0281] Furthermore, the first housing 6001 and the second housing 6003 can be separated by the hinge portion 6005. It can also be configured to allow for conversion (a so-called convertible type). By adopting such a configuration, for example, The first enclosure 6001 is used in a vertical orientation, and the second enclosure 6003 is used in a horizontal orientation. As such, it is suitable because it expands the range of applications.

[0282] Furthermore, 3D images are captured using the first camera 6013 and the second camera 6015. It is also possible to do so.

[0283] Furthermore, the tablet terminals 5000 and 6000 transmit information wirelessly. It may also be configured to receive signals. For example, it may connect to the internet wirelessly and receive the desired signal. It is also possible to configure the system so that users purchase and download the information.

[0284] Furthermore, the tablet terminals 5000 and 6000 can display various information (static Features to display still images, videos, text images, etc., calendar, date or time, etc. A function to display information on the display unit, and a touch input function to perform touch input operations or edit the information displayed on the display unit. It can have functions to control processing using various software (programs), etc. It can do that. In addition, it can use a light sensor that can optimize the display brightness according to the amount of ambient light, and Detection devices such as color sensors and acceleration sensors that detect tilt may be incorporated.

[0285] The semiconductor device shown in the above embodiment is used as the display unit 5003 of the tablet terminal 5000. The first display unit 6007 and / or the second display unit 6009 of the bullet-type terminal 6000 By applying this, it has stable electrical characteristics and reduces signal delay caused by wiring resistance. It can be a tablet device without a physical tablet.

[0286] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. It is Noh. [Explanation of Symbols]

[0287] 102 circuit boards 104 Guard gate 104a First gate electrode 104b Second gate electrode 106 Gate insulating film 106a First gate insulating film 106b Second gate insulating film 10⁸ Oxide semiconductor film 109a First metal film 109b Second metal film 10⁹c Third metal film 110 Source Electrode 110a First metal film 110b Second metal film 110c Third metal film 112 Drain electrode 112a First metal film 112b Second metal film 112c Third metal film 114a First insulating film 114b Second insulating film 115 Aluminum film 116 Aluminum oxide film 118 Planarizing Insulating Film 141 Resist Mask 142 Resist Mask 145 Oxygen 147 Oxygen 150 transistors 204 Shuttle gate 204a First gate electrode 204b Second gate electrode 206 Gate Insulator 206a First gate insulating film 206b Second gate insulating film 209a First metal film 209b Second metal film 209c Third metal film 210 Source Electrodes 210a First metal film 210b Second metal film 210c Third metal film 212 Drain electrode 212a First metal film 212c Third metal film 232 signal line 241 Resist Mask 242 Resist Mask 250 transistors 260 signal line area 300 circuit boards 301 circuit board 302 pixel section 304 Source Driver Circuit 306 Gate Driver Circuit Section 308 FPC terminal section 310 signal line 312 Sealant 316 FPC 350 transistors 352 transistors 360 terminal electrode 360a First metal film 360b Second metal film 360c Third Metal Film 364 Insulating Film 366 Protective insulating film 368 Planarizing insulating film 370a conductive film 370b Conductive film 380 Anisotropic conductive film 402 liquid crystal elements 404 Opposite electrode 406 Liquid Crystal Layer 410 Insulating film 412 Insulating film 435 Spacer 450 light-emitting elements 452 Electroluminescent layer 454 Upper electrode 456 Bulkhead 458 Filling material 2700 eBooks 2701 enclosure 2703 Casing 2705 ​​Display section 2707 Display section 2711 Shaft 2721 Power supply 2723 Operation Keys 2725 Speakers 2800 cabinets 2801 enclosure 2802 Display Panel 2803 Speaker 2804 Microphone 2805 Operation Keys 2806 Pointing device 2807 Camera Lens 2808 External connection terminal 2810 solar cells 2811 External memory slot 3001 Main Unit 3002 enclosure 3003 Display section 3004 Keyboard 3021 Main Unit 3022 Stylus 3023 Display section 3024 Operation Buttons 3025 External Interface 3051 Main Unit 3053 Eyepiece 3054 Operation switch 3056 Battery 5000 tablet devices 5001 enclosure 5003 Display section 5005 Power button 5007 Front Camera 5009 Rear Camera 5011 External connection terminal 5013 External connection terminal 5015 Icons 6000 tablet devices 6001 enclosure 6003 enclosure 6005 Hinge section 6007 Display section 6009 Display section 6011 Power button 6013 Camera 6015 Camera 6017 Text Icon 6019 Icons 6021 Keyboard 9600 Television equipment 9601 enclosure 9603 Display section 9605 Stand

Claims

1. A liquid crystal display device having transistors in the pixel portion, A first conductive film having the function of a photoelectrode of the transistor, A first insulating film having a region positioned above the first conductive film, An oxide semiconductor film having a region positioned above the first insulating film and having a channel formation region for the transistor, A second conductive film having a region positioned above the oxide semiconductor film and functioning as either a source electrode or a drain electrode, A third conductive film having a region positioned above the oxide semiconductor film and functioning as either a source electrode or a drain electrode, A second insulating film having a region positioned above the second conductive film, a region positioned above the third conductive film, and a region in contact with the upper surface of the oxide semiconductor film, Each of the second and third conductive films comprises a first metal film, a second metal film having a region in contact with the upper surface of the first metal film, and a third metal film having regions in contact with the upper and side surfaces of the second metal film. The first metal film comprises one of tungsten, tantalum, titanium, and molybdenum. The second metal film contains copper, The first metal film has a region that is in contact with the upper surface of the oxide semiconductor film, The third metal film does not have a region in contact with the oxide semiconductor film. The third metal film has a region that is in contact with the upper surface of the first metal film. LCD display device.

2. A liquid crystal display device having transistors in the pixel portion, A first conductive film having the function of a photoelectrode of the transistor, A first insulating film having a region positioned above the first conductive film, An oxide semiconductor film having a region positioned above the first insulating film and having a channel formation region for the transistor, A second conductive film having a region positioned above the oxide semiconductor film and functioning as either a source electrode or a drain electrode, A third conductive film having a region positioned above the oxide semiconductor film and functioning as either a source electrode or a drain electrode, A second insulating film having a region positioned above the second conductive film, a region positioned above the third conductive film, and a region in contact with the upper surface of the oxide semiconductor film, The first insulating film comprises a first film containing nitrogen and silicon, and a second film having a region positioned above the first film and containing oxygen and silicon. Each of the second and third conductive films comprises a first metal film, a second metal film having a region in contact with the upper surface of the first metal film, and a third metal film having regions in contact with the upper and side surfaces of the second metal film. The first metal film comprises one of tungsten, tantalum, titanium, and molybdenum. The second metal film contains copper, The first metal film has a region that is in contact with the upper surface of the oxide semiconductor film, The third metal film does not have a region in contact with the oxide semiconductor film. The third metal film has a region that is in contact with the upper surface of the first metal film. LCD display device.

3. In claim 1 or claim 2, The oxide semiconductor film comprises a first oxide semiconductor film and a second oxide semiconductor film having a region located above the first oxide semiconductor film. LCD display device.

4. In any one of claims 1 to 3, The third metal film has the function of suppressing the diffusion of copper elements from the second metal film. LCD display device.

Images