Semiconductor equipment

Abstract

To provide a semiconductor device with minimal variation in characteristics. [Solution] A first insulator, a transistor on the first insulator, and a second on the transistor An insulator, a third insulator on the second insulator, a fourth insulator on the third insulator, and an opening The region has a second insulator and a third insulator on the second insulator, and the third The third insulator has an opening that reaches the second insulator, and the third insulator has a fourth insulator on the insulator. The fourth insulator is in contact with the upper surface of the second insulator within the opening.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a transistor, a semiconductor device, and electronic equipment. One aspect of the present invention relates to a method for manufacturing a semiconductor device. Another aspect of the present invention relates to a semiconductor wafer , and regarding modules.

[0002] In this specification, a semiconductor device refers to a device that can function by utilizing semiconductor properties. This refers to semiconductor devices in general, including semiconductor elements such as transistors, semiconductor circuits, computing devices, and memory devices. A device is one form of a semiconductor device. Display devices (liquid crystal display devices, light-emitting display devices, etc.), projection Devices, lighting devices, electro-optical devices, energy storage devices, memory devices, semiconductor circuits, imaging devices, electronic equipment Some devices, such as those mentioned above, can be said to possess semiconductor devices.

[0003] Furthermore, one aspect of the present invention is not limited to the above-mentioned technical field. One aspect of the present invention relates to a product, method, or method of manufacture. Another aspect of the present invention is , process, machine, manufacture, or composition of matter This concerns (—). [Background technology]

[0004] In recent years, the development of semiconductor devices has progressed, and LSIs, CPUs, and memory are mainly used. A CPU is a semiconductor integrated circuit (at least transistors) made by processing semiconductor wafers and forming them into chips. It is an assembly of semiconductor elements having a gista (and memory) and electrodes that serve as connection terminals. .

[0005] Semiconductor circuits (IC chips) such as LSIs, CPUs, and memory are mounted on circuit boards, such as printers. It is mounted on a circuit board and used as one of the components in various electronic devices.

[0006] Furthermore, a transistor is constructed using a semiconductor thin film formed on a substrate having an insulating surface. The technology is attracting attention. This transistor is used in integrated circuits (ICs) and image display devices (simply display). It is widely applied to electronic devices (also referred to as devices). Applicable to transistors. Silicon-based semiconductor materials are widely known as capable semiconductor thin films, but other materials include Oxide semiconductors are attracting attention.

[0007] Furthermore, transistors using oxide semiconductors have extremely low leakage current in the non-conductive state. It is known to be small. For example, the leakage current of a transistor using an oxide semiconductor is Low-power CPUs and other devices that take advantage of this characteristic have been disclosed (see Patent Document 1). ). Also, for example, the characteristic of low leakage current in transistors using oxide semiconductors. Applications of this technology include the disclosure of memory devices that can retain memory contents over long periods of time. (See Patent Document 2.)

[0008] Furthermore, in recent years, with the miniaturization and weight reduction of electronic devices, the need for even higher density integrated circuits has increased. Demand is increasing. Furthermore, there is a need for improved productivity in semiconductor devices, including integrated circuits. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2012-257187 [Patent Document 2] Japanese Patent Publication No. 2011-151383 [Overview of the project] [Problems that the invention aims to solve]

[0010] One aspect of the present invention provides a semiconductor device with less variation in transistor characteristics. One of the challenges is to provide a reliable semiconductor device. Alternatively, one aspect of the present invention is to provide a reliable semiconductor device. This is one of the challenges. Alternatively, one aspect of the present invention provides a semiconductor device having good electrical characteristics. One of the objectives is to provide a semiconductor with a high on-current. Alternatively, one aspect of the present invention is a semiconductor with a high on-current. One of the objectives of the present invention is to provide an apparatus for miniaturization or high concentration. One of the objectives is to provide a semiconductor device that can be integrated. Alternatively, one aspect of the present invention is One of the challenges is to provide low-power semiconductor devices.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. One approach does not require that all of these issues be resolved. The title will become clear from the description in the specification, drawings, claims, etc. It is possible to extract other issues from the descriptions in the drawings, claims, etc. [Means for solving the problem]

[0012] One aspect of the present invention comprises a first insulator, a transistor on the first insulator, and a transistor The second insulator above, the third insulator on the second insulator, and the fourth insulator on the third insulator The structure has an opening region, and the opening region comprises a second insulator and a third insulator on the second insulator. And a fourth insulator on the third insulator, and an opening in the third insulator that reaches the second insulator, A semiconductor device having a fourth insulator that is in contact with the upper surface of the second insulator inside the opening. ru.

[0013] Furthermore, one aspect of the present invention includes a first insulator, a transistor on the first insulator, and a transistor A second insulator on the zistor, a third insulator on the second insulator, and a fourth insulator on the third insulator The device comprises an insulator and an opening region, the opening region being connected to a second insulator and a third insulator on the second insulator. A rim, a fourth insulator on the third insulator, and an opening in the third insulator that reaches the second insulator The transistor has a fourth insulator that is in contact with the upper surface of the second insulator inside the opening, and It comprises a first insulator, a fifth insulator on the first insulator, an oxide on the fifth insulator, and an oxide. The first conductor and the second conductor are located on the first conductor and on the second conductor. 6 insulators and 7 conductors located on an oxide and positioned between the first and second conductors The insulator has a third conductor on the seventh insulator, and the sixth insulator has a second insulator It is a semiconductor device that makes contact with [something].

[0014] Furthermore, in the above configuration, it is preferable that the fourth insulator is further in contact with the first insulator.

[0015] Furthermore, in the above, the seventh insulator is the eighth insulator and the ninth insulator on the eighth insulator The insulator has a body and a third conductor, the eighth insulator is in contact with the second insulator, and the ninth insulator is in contact with the third conductor. Contact is preferable.

[0016] Furthermore, in the above, the first insulator and the third insulator are silicon and nitrogen. It is preferable to include it.

[0017] Furthermore, in the above, the second insulator and the sixth insulator are AlO x (x is greater than 0) It is preferable that the number is any number.

[0018] Furthermore, in the above, the fifth insulator and the ninth insulator preferably contain hafnium. stomach.

[0019] Furthermore, in the above, the oxide is selected from In, Ga, or Zn. Alternatively, it is preferable that the oxide semiconductor contains multiple such elements.

[0020] Furthermore, in one aspect of the present invention, a first insulator is formed, and an oxide film is formed on the first insulator. A first heat treatment is performed to sequentially deposit a first conductive film and a first insulating film on the oxide film. The first insulator, oxide film, first conductive film, and first insulating film are processed into island shapes to form the first insulating film On the edge body, an oxide, a conductive layer, and an insulating layer are formed, and the first insulator, oxide, conductive layer, A second insulator is formed on the insulating layer, and a third insulator is formed on the second insulator. A first opening reaching the oxide is formed in the electrolytic layer, the insulating layer, the second insulator, and the third insulator. In the formation of the first opening, a first conductor and a second conductor are formed from the conductive layer. Then, a fourth insulator and a fifth insulator are formed from the insulating layer, and a second heat treatment is performed. A second insulating film is formed on the third insulator and on the first opening, and a first microwave treatment is performed. Perform the following steps: deposit a third insulating film on the second insulating film, perform a second microwave treatment, and then perform the third insulating film. A second conductive film is formed on the edge film, and the second insulating film, the third insulating film, and the second conductive film are then formed. Perform CMP treatment until the top surface of the third insulator is exposed, then proceed to the sixth insulator and the seventh insulator. , and form a third conductor, a third insulator, a sixth insulator, a seventh insulator, and the An eighth insulator is formed on the third conductor, and a second opening reaches the third insulator on the eighth insulator. A mouth is formed, and a third heat treatment is performed, and the temperature of the first heat treatment is lower than the temperature of the third heat treatment. This is a highly efficient method for manufacturing semiconductor devices.

[0021] Furthermore, in the above, the first insulating film, the second insulator, and the eighth insulator are aluminum oxide. It is preferable to form a film of aluminum.

[0022] Furthermore, in the above, the first microwave processing and the second microwave processing are less Both processes are carried out in an oxygen atmosphere and at a temperature range of 100°C to 750°C. preferable.

[0023] Furthermore, in the above, the first microwave processing and the second microwave processing are 300 It is preferable that the process be carried out in a temperature range of 500°C or higher.

[0024] Furthermore, in the above, the first microwave processing and the second microwave processing are 300 It is preferable that the procedure be carried out in a pressure range of Pa to 700 Pa.

[0025] Furthermore, in the above, the first heat treatment is performed under a nitrogen atmosphere at a temperature of 250°C to 650°C. The process is carried out within the range below, continuously, under an oxygen atmosphere, at a temperature between 250°C and 650°C. It is preferable that it be broken.

[0026] Furthermore, in the above, the second heat treatment is performed in an oxygen atmosphere at a temperature of 350°C to 400°C. The process is carried out within the range below, continuously, under a nitrogen atmosphere, at a temperature between 350°C and 400°C. It is preferable that it be broken.

[0027] Furthermore, in the above, the third heat treatment is performed under a nitrogen atmosphere at a temperature of 350°C to 400°C. It is preferable that the following be carried out within the scope below. [Effects of the Invention]

[0028] According to one aspect of the present invention, a semiconductor device with less variation in transistor characteristics is provided. This is possible. Alternatively, according to one aspect of the present invention, a reliable semiconductor device can be provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device having good electrical characteristics is provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device with a large on-current is provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor that can be miniaturized or highly integrated can be produced. An apparatus can be provided. Or, according to one aspect of the present invention, a low-power semiconductor device can be provided. We can provide this.

[0029] Furthermore, the description of these effects does not preclude the existence of other effects. One embodiment does not need to have all of these effects. Other effects are described in the specification. This will become clear from the description in the drawings, claims, etc., and the specification, drawings, claims From descriptions such as these, it is possible to extract other effects. [Brief explanation of the drawing]

[0030] [Figure 1] Figure 1 is a top view of a semiconductor device according to one embodiment of the present invention. [Figure 2] Figure 2A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 2B and 2C are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 3] Figure 3A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 3B to 3D are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 4] Figure 4 is a cross-sectional view of a semiconductor device according to one aspect of the present invention. [Figure 5]Figure 5A is a diagram illustrating the classification of IGZO crystal structures. Figure 5B is a diagram illustrating the XRD spectrum of a CAAC-IGZO film. Figure 5C is a diagram illustrating the micro-electron diffraction pattern of a CAAC-IGZO film. [Figure 6] Figure 6A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 6B to 6D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 7] Figure 7A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 7B to 7D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 8] Figure 8A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 8B to 8D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 9] Figure 9A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 9B to 9D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 10] Figure 10A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 10B to 10D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 11] Figure 11A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 11B to 11D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 12] Figure 12A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 12B to 12D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 13] Figure 13A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 13B to 13D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 14] Figure 14A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 14B to 14D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 15] Figure 15A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 15B to 15D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 16] Figure 16A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 16B to 16D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 17] Figure 17A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 17B to 17D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 18] Figure 18A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 18B to 18D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 19] Figure 19A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 19B to 19D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 20] Figure 20A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 20B to 20D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 21] Figure 21A is a top view showing a method for manufacturing a semiconductor device according to one aspect of the present invention. Figures 21B to 21D are cross-sectional views showing a method for manufacturing a semiconductor device according to one aspect of the present invention. [Figure 22] Figure 22 is a top view illustrating a microwave processing apparatus according to one aspect of the present invention. [Figure 23] Figure 23 is a cross-sectional view illustrating a microwave processing apparatus according to one aspect of the present invention. [Figure 24] Figure 24 is a cross-sectional view illustrating a microwave processing apparatus according to one aspect of the present invention. [Figure 25] Figure 25A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 25B to 25D are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 26] Figure 26A is a top view of a semiconductor device according to one embodiment of the present invention. Figure 26B is a cross-sectional view of a semiconductor device according to one embodiment of the present invention. [Figure 27] Figure 27A is a top view of a semiconductor device according to one embodiment of the present invention. Figure 27B is a cross-sectional view of a semiconductor device according to one embodiment of the present invention. [Figure 28] Figure 28A is a top view of a semiconductor device according to one embodiment of the present invention. Figure 28B is a cross-sectional view of a semiconductor device according to one embodiment of the present invention. [Figure 29] Figures 29A and 29B are cross-sectional views of a semiconductor device according to one aspect of the present invention. [Figure 30] Figure 30 is a cross-sectional view showing the configuration of a storage device according to one aspect of the present invention. [Figure 31] Figure 31 is a cross-sectional view showing the configuration of a storage device according to one aspect of the present invention. [Figure 32] Figures 32A and 32B are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 33] Figures 33A and 33B are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 34] Figure 34 is a cross-sectional view of a semiconductor device according to one aspect of the present invention. [Figure 35] Figure 35 is a cross-sectional view of a semiconductor device according to one aspect of the present invention. [Figure 36] Figures 36A and 36B are block diagrams showing an example of the configuration of a storage device according to one aspect of the present invention. [Figure 37] Figures 37A to 37H are circuit diagrams showing an example of the configuration of a storage device according to one aspect of the present invention. [Figure 38] Figure 38 is a diagram showing various types of storage devices in a hierarchical structure. [Figure 39] Figures 39A and 39B are schematic diagrams of a semiconductor device according to one aspect of the present invention. [Figure 40] Figures 40A and 40B illustrate an example of an electronic component according to one aspect of the present invention. [Figure 41]Figures 41A to 41E are schematic diagrams of a storage device according to one aspect of the present invention. [Figure 42] Figures 42A to 42H show an electronic device according to one aspect of the present invention. [Figure 43] Figures 43A to 43C show the electrical characteristics of an embodiment according to one aspect of the present invention. [Figure 44] Figures 44A to 44C show the electrical characteristics of an embodiment according to one aspect of the present invention. [Figure 45] Figures 45A to 45H show the temperature dependence of the electrical characteristics of an embodiment according to one aspect of the present invention. [Figure 46] Figures 46A to 46C show the electrical characteristics of an embodiment according to one aspect of the present invention. [Figure 47] Figures 47A to 47C show the electrical characteristics of an embodiment according to one aspect of the present invention. [Figure 48] Figures 48A to 48H show the Vbg dependence of the electrical characteristics of an embodiment according to one aspect of the present invention. [Modes for carrying out the invention]

[0031] The embodiments will be described below with reference to the drawings. However, many embodiments are described. It can be implemented in different ways, without deviating from its purpose and scope. It will be readily apparent to those skilled in the art that the form and details can be varied in various ways. Therefore, the present invention shall not be construed as being limited to the contents described in the following embodiments.

[0032] Furthermore, in the drawings, the size, layer thickness, or area may be exaggerated for clarity. This may be the case. Therefore, it is not necessarily limited to that scale. Note that the drawing is an ideal This is a schematic example and is not limited to the shapes or values ​​shown in the diagram. For example, In the actual manufacturing process, processes such as etching can cause layers and resist masks to be altered as intended. Although there may be some reduction in volume, this may not be reflected in the diagram for the sake of easier understanding. In drawings, the same reference numeral is used for identical parts or parts having similar functions across different drawings. It is used in common, and explanations of its repetition may be omitted. Also, in cases where similar functions are referred to... In some cases, the hatch patterns are the same, and no specific designation is assigned.

[0033] Furthermore, the invention is made easier to understand, especially in top views (also called "plan views") and perspective views. Therefore, the description of some components may be omitted. Also, some hidden lines and other markings may be omitted. The word "included" may be omitted in some cases.

[0034] Furthermore, the ordinal numbers used in this specification, etc., as "1st," "2nd," etc., are used for convenience only. It does not indicate the order of processes or stacking order. Therefore, for example, "the first" should be written as "the second". This can be explained by appropriately replacing it with "of" or "the third of," etc. The ordinal numbers described herein do not correspond to the ordinal numbers used to specify one aspect of the present invention. There are cases where this is the case.

[0035] Furthermore, in this specification, phrases indicating placement such as "above" and "below" refer to the relative positions of the components. The positional relationships are used for convenience in explaining them by referring to the diagram. Also, the positions of the components are shown. The relationships change as appropriate depending on the direction in which each component is described. Therefore, in the specification... The terms explained are not limited to those used in the text; they can be appropriately rephrased depending on the context.

[0036] For example, in this specification, it is explicitly stated that X and Y are connected. In this case, X and Y are electrically connected, and X and Y are functionally connected. The cases disclosed in this specification, etc., include cases where X and Y are directly connected. Therefore, it is limited to predetermined connection relationships, for example, connection relationships shown in a diagram or text. Furthermore, connections other than those shown in the diagram or text are also disclosed in the diagram or text. Let X and Y be the objects (e.g., devices, elements, circuits, wiring, electrodes, terminals). (Conductive film, layer, etc.)

[0037] Furthermore, in this specification, the term "transistor" includes a gate, a drain, and a source. It is an element having at least three terminals. And, drain (drain terminal, drain Between the drain region (or drain electrode) and the source (source terminal, source region, or source electrode) It has a region where channels are formed (hereinafter also called the channel-forming region), This design allows current to flow between the source and drain through a flannel-formed region. In this specification, the channel-forming region refers to the region through which electric current primarily flows.

[0038] Furthermore, the source and drain functions may differ when using transistors with different polarities, or when the circuit The direction of the current may change during operation, which can cause the current to switch positions. In detailed documents, the terms "source" and "drain" may be used interchangeably. ru.

[0039] Note that channel length refers to, for example, the length of the semiconductor (or transistor) in a top view of a transistor. When the inverter is ON, the part of the semiconductor through which current flows and the gate electrode overlap each other. In the region or channel-forming region, the source (source region or source electrode) and This refers to the distance between the drain (drain region or drain electrode) and the other element. In a zista, the channel length is not necessarily the same across all regions. That is, one The channel length of the transistor may not be fixed to a single value. Therefore, this specification So, the channel length is any one value, maximum value, minimum value, or This will be the average value.

[0040] Channel width refers to, for example, the top view of a transistor, the semiconductor (or transistor) The region where the gate electrode and the part of the semiconductor through which current flows when the gate electrode is ON overlap each other. Channels in a region or channel-forming region, perpendicular to the channel length direction. This refers to the length of the formation region. Note that in a single transistor, the channel width encompasses the entire region. They do not necessarily take the same value. In other words, the channel width of a single transistor is a single value. It may not be fixed. Therefore, in this specification, the channel width is defined as the channel formation region. This is one of the values, the maximum value, the minimum value, or the average value.

[0041] In this specification, depending on the transistor structure, channel formation may actually occur. The channel width in the region (hereinafter also referred to as the "effective channel width") and the transition The channel width shown in the top view of the stylus (hereinafter also referred to as the "apparent channel width") is as follows. ) and may differ. For example, when the gate electrode covers the side of the semiconductor, the effective ch When the channel width becomes larger than the apparent channel width, and its effect can no longer be ignored. For example, in a transistor that is very small and whose gate electrode covers the side of the semiconductor, the semiconductor In some cases, the proportion of channel-forming regions formed on the sides may increase. In such cases, the apparent The effective channel width will be larger than the channel width shown above.

[0042] In such cases, it can be difficult to estimate the effective channel width through actual measurements. For example, in order to estimate the effective channel width from the design value, the shape of the semiconductor is known. A certain assumption is necessary. Therefore, if the shape of the semiconductor is not precisely known, the effective It is difficult to accurately measure channel width.

[0043] In this specification, when simply referred to as "channel width," it refers to the apparent channel width. There is. Or, in this specification, when simply referred to as channel width, it means effective channel It can refer to width. Note that it can also refer to channel length, channel width, effective channel width, or apparent width. Channel width and other parameters can be determined by analyzing cross-sectional TEM images, etc. can.

[0044] Furthermore, semiconductor impurities refer to components other than the main components that make up the semiconductor, for example, concentrated Elements with a concentration of less than 0.1 atomic percent are considered impurities. The presence of impurities can, for example, lead to... In some cases, this can lead to an increase in the defect level density of semiconductors or a decrease in crystallinity. If the semiconductor is an oxide semiconductor, impurities that change the properties of the semiconductor include, for example, Group 1 elements, Group 2 elements, Group 13 elements, Group 14 elements, Group 15 elements, oxide semiconductors Other components besides the main component include transition metals, such as hydrogen, lithium, sodium, silicon, These include boron, phosphorus, carbon, and nitrogen. Note that water can also function as an impurity. For example, the inclusion of impurities can cause oxygen vacancies (V) in oxide semiconductors. O :oxygen va In some cases, cancy (also known as cancy) may form.

[0045] In this specification, silicon oxidnitride is defined as having a composition that contains more oxygen than nitrogen. It has a high content of [something]. Also, silicon nitride oxide, in terms of its composition, has more oxygen than [something]. It has a high nitrogen content. Similarly, aluminum oxide nitride has the following composition: It has a higher oxygen content than nitrogen. Also, aluminum nitride oxide has a higher oxygen content. It has a higher nitrogen content than oxygen content. Similarly, hafnium oxide-nitride is Its composition has a higher oxygen content than nitrogen. Also, hafnium nitride oxide. This refers to a substance whose composition contains more nitrogen than oxygen.

[0046] Furthermore, in this specification, the term "insulator" shall be replaced with "insulating film" or "insulating layer." It is possible to replace the term "conductor" with "conductive film" or "conductive layer." This is possible. Also, the term "semiconductor" can be replaced with "semiconductor film" or "semiconductor layer." can.

[0047] Furthermore, in this specification, "parallel" means that two straight lines have an angle of -10 degrees or more and 10 degrees or less. This refers to a state where objects are arranged in degrees. Therefore, it also includes cases where the angle is between -5 degrees and 5 degrees. Furthermore, "approximately parallel" means that two straight lines are positioned at an angle of -30 degrees or more and 30 degrees or less. It refers to a state or condition. Also, "perpendicular" means that two straight lines are positioned at an angle of 80 degrees or more and 100 degrees or less. This refers to a state in which the temperature is between 85 and 95 degrees. Therefore, it also includes cases between 85 and 95 degrees. "Perpendicular" refers to a state where two straight lines are positioned at an angle between 60 degrees and 120 degrees.

[0048] In this specification, metal oxide refers to metal in a broad sense. It is an oxide. Metal oxides are oxide insulators and oxide conductors (including transparent oxide conductors). . ), oxide semiconductor (also called Oxide Semiconductor or simply OS) They are classified into categories such as . ) For example, when a metal oxide is used in the semiconductor layer of a transistor, The metal oxide in question is sometimes referred to as an oxide semiconductor. Therefore, it is sometimes described as an OS transistor. In such cases, it can be rephrased as a transistor having a metal oxide or oxide semiconductor. It is possible.

[0049] Furthermore, in this specification, normally off means not applying a potential to the gate, or When the gate is given a ground potential, the amount of drape flowing through the transistor per 1 μm of channel width is The current is 1 × 10 at room temperature. -20 A or less, 1 × 10 at 85℃ -18 Below A , or 1 × 10 at 125℃ -16 This means being less than or equal to A.

[0050] (Embodiment 1) In this embodiment, Figures 1 to 24 illustrate a semiconductor device 500 according to one aspect of the present invention. An example and its manufacturing method will be described.

[0051] Figure 1 is a top view of the semiconductor device 500. The semiconductor device 500 has multiple transistors. It has a 200, multiple opening regions 400, and a sealing portion 265. Also, as shown in Figure 1 , a sealing portion 26 surrounding multiple transistors 200 and multiple aperture regions 400 5 is positioned. Note that the number of transistors 200 in the semiconductor device 500 is shown in Figure 1. The number is not limited to those shown. In other words, the number of transistors per unit area of ​​semiconductor device 500. The number of 200, that is, the arrangement density of transistor 200, is as shown in Figure 1. The number of aperture regions 400 may be greater or less than the arrangement density. The arrangement density of transistors 200 should be adjusted as appropriate. Preferably, semiconductor The higher the density of transistors 200 placed in the device 500, the larger the aperture region 40 Reduce the number of zeros. For example, the aperture region 400 is inversely proportional to the arrangement density of the transistors 200. You may arrange the number shown as an example. Alternatively, the total area of ​​the opening region 400 (above one opening region 400) The sum of the surface area and the number of aperture regions 400 is when the arrangement density of transistors 200 is small. The larger the size, the smaller the size, and the higher the arrangement density of transistors 200, the more desirable it is. stomach.

[0052] Figure 2A is an enlarged view of the region 291 enclosed by the dashed line in Figure 1. Also, Figure 2B is Figure 2A shows a cross-sectional view of the area indicated by the dashed line A1-A2, and the channel of transistor 200. Figure 2C is a cross-sectional view in the direction of the flannel, and also a cross-sectional view of the sealing portion 265. Furthermore, Figure 2C is a cross-sectional view of Figure 2A. This is a cross-sectional view of the area indicated by the dashed line in 3-A4, a cross-sectional view of the opening region 400, and the sealing portion. This is also a cross-sectional view of the 265.

[0053] As shown in Figure 2A, in the A1-A2 direction, the transistor 200 It is positioned along a length L1 from the end of the 200 to the end of the sealing portion 265, and perpendicular to A1-A2. In terms of direction, the length L2 from the end of the transistor 200 to the end of the sealing portion 265 is distributed It is positioned. Also, the opening region 400 has a length L3 in the direction perpendicular to A1-A2. They are arranged at intervals. Here, length L3 is in the direction perpendicular to A1-A2, adjacent to This is the distance between the upper parts of the opening region 400. Also, the shape of the opening region 400 when viewed from above is The shape is not limited to the rectangle shown in Figure 2A. For example, the shape of the opening region 400 in a top view is correct. This includes square, elliptical, circular, rhombus, or combinations thereof. Also, length L1 The length L2 is 0.10 μm or more and 2.0 μm or less, preferably 0.15 μm or more. The diameter should be 5 μm or less. Also, the length L3 should be between 1.5 μm and 6.0 μm. Typically... The thickness is set to 1.5 μm.

[0054] As shown in Figures 2B and 2C, the semiconductor device 500 is an insulator 21 on a substrate (not shown). 2, an insulator 214 on the insulator 212, and multiple transistors 200 on the insulator 214. , insulator 280 on transistor 200, insulator 282 on insulator 280, and insulator 2 The sealing portion 2 where the insulator 283 on 82 and a part of the upper surface of the insulator 212 are in contact with the insulator 283 It has 65 and an opening region 400 in which a part of the insulator 282 is open. In 00, the insulator 280 may have a recess, and the depth of the recess of the insulator 280 is The maximum film thickness of the insulator 280 in the semiconductor device 500 shall be between 1 / 4 and 1 / 2.

[0055] Furthermore, by performing a heat treatment after the formation of the opening region 400 in the manufacturing process of the semiconductor device 500, The oxygen contained in the insulator 280, and the hydrogen bonded to that oxygen, are transferred through the opening region 400. It can be released to the outside. Furthermore, hydrogen that combines with oxygen is released as water. Therefore This reduces the amount of unwanted oxygen and hydrogen contained in the insulator 280.

[0056] <Example of semiconductor device configuration> Using Figures 3A to 3D, a semiconductor having a transistor 200 and an aperture region 400 is shown. An example of the device configuration is described below. Figures 3A to 3D show the transistor 200 and the aperture region. Figure 3A shows a top view and a cross-sectional view of a semiconductor device having 400. This is a top view. Figures 3B to 3D are cross-sectional views of the semiconductor device. Here, Figure 3 B is a cross-sectional view of the area shown by the dashed line A1-A2 in Figure 3A, and is of transistor 200. This is also a cross-sectional view in the direction of the channel length. Furthermore, Figure 3C is shown in Figure 3A by the dashed line A3-A4. This is a cross-sectional view of the area, and also a cross-sectional view of transistor 200 in the channel width direction. Figure 3D is a cross-sectional view of the area shown by the dashed line A5-A6 in Figure 3A, and the opening region 400 This is also a cross-sectional view. Note that in the top view of Figure 3A, some elements have been omitted for clarity. ru.

[0057] A semiconductor device according to one aspect of the present invention comprises an insulator 212 on a substrate (not shown) and an insulator 212 The insulator 214 above, the transistor 200 on the insulator 214, and the transistor 200 above Insulator 280, and insulator 282 on insulator 280 (insulator 282a, and insulator 282 b) an insulator 283 on the insulator 282, an insulator 286 on the insulator 283, and a sealing portion 2 It has an insulator 274 on 65. In addition, the insulator 283 is on the side of the insulator 282, insulating Side of body 280, side of transistor 200, side of insulator 214, and insulator 212 It is in contact with a part of the upper surface. Insulator 212, insulator 214, insulator 280, insulator 282, The edge material 283, insulator 286, and insulator 274 function as interlayer films. Conductor 240 (conductor 240a, and has a conductor 240b). Note that the side surface of the conductor 240 which functions as a plug is in contact And an insulator 241 (insulator 241a and insulator 241b) is provided. On body 286 and on conductor 240, there are wires that are electrically connected to conductor 240 and serve as wiring. Conductive elements 246 (conductors 246a and 246b) are provided.

[0058] In contact with the inner wall of the opening of insulator 280, insulator 282, insulator 283, and insulator 286 An insulator 241a is provided, and the first conductor 240a is in contact with the side surface of the insulator 241a. An electric element is provided, and further inside, a second conductive element, conductive element 240a, is provided. In contact with the inner wall of the opening of insulator 280, insulator 282, insulator 283, and insulator 286 An insulator 241b is provided, and the first conductive material of the conductor 240b is in contact with the side surface of the insulator 241b. A body is provided, and further inside, a second conductive material, conductive material 240b, is provided. Here, The height of the top surface of the conductor 240 and the height of the top surface of the insulator 286 in the region overlapping with the conductor 246. And can be done to the same extent. In addition, in transistor 200, the first conductor of conductor 240 The present invention shows a configuration in which the second conductor of the conductor 240 is laminated, but the present invention relates to this It is not limited to this. For example, the conductor 240 can be used as a single layer or a laminated structure of three or more layers. The structure may be configured to include ordinal numbers. If the structure has a layered structure, ordinal numbers may be assigned to distinguish it from the structure in the order of formation. It may happen.

[0059] [Transistor 200] As shown in Figures 3A to 3C, the transistor 200 is located on the insulator 214. 6 and a conductor 205 ( arranged to be embedded in the insulator 214 or insulator 216) Conductors 205a, 205b, and 205c), and on the insulator 216, Insulator 222 on conductor 205, insulator 224 on insulator 222, and on insulator 224 Oxide 230a, oxide 230b on oxide 230a, and oxide on oxide 230b 243 (oxide 243a and oxide 243b), and conductor 242 on oxide 243a a, an insulator 271a on the conductor 242a, and a conductor 242b on the oxide 243b, Insulator 271b on the electrode 242b, insulator 250a on the oxide 230b, and insulator 25 The insulator 250b on 0a and the part located on the insulator 250b that overlaps with a portion of the oxide 230b Conductor 260 (conductor 260a and conductor 260b), insulator 224, oxide 23 0 (Oxide 230a and oxide 230b), oxide 243, conductor 242 (conductor 2 42a, and conductor 242b), insulator 271 (insulator 271a, and insulator 271 b) comprises an insulator 272 positioned to cover it. Here, as shown in Figures 3B to 3D As such, the insulator 272 has a region that is in contact with a part of the upper surface of the insulator 222. The upper surface of the electric body 260 is positioned to substantially coincide with the upper surface of the insulator 250 and the upper surface of the insulator 280. In addition, the insulator 282 is connected to the conductor 260, the insulator 250, and the insulator 280. It contacts the top surface of each.

[0060] In the following, oxides 230a and 230b will be collectively referred to as oxide 230. There are cases where insulator 250a and insulator 250b are collectively referred to as insulator 250. There are also cases where insulators 271a and 271b are collectively referred to as insulator 271. ru.

[0061] The insulators 280 and 272 are provided with openings that reach the oxide 230b. An insulator 250 and a conductor 260 are placed within the opening. In the channel length direction of TA200, insulator 271a, conductor 242a and oxide 24 3a, insulator 271b, conductor 242b and oxide 243b, and conductor 260 , and an insulator 250 is provided. The insulator 250 is in contact with the side surface of the conductor 260. It has a region and a region that is in contact with the bottom surface of the conductor 260.

[0062] Oxide 230 consists of oxide 230a placed on the insulator 224 and oxide 230a Preferably, the oxide 230b is placed on top, and the oxide is placed below the oxide 230b. Having 230a, the oxide 2 This can suppress the diffusion of impurities into 30b.

[0063] In transistor 200, oxide 230 is oxide 230a and oxide 23 Although the present invention shows a configuration in which two layers of 0b are stacked, the present invention is not limited to this. For example, the configuration may consist of a single layer of oxide 230b or a laminated structure of three or more layers. Furthermore, oxide 230a and oxide 230b may each have a layered structure.

[0064] Conductor 260 functions as the first gate (also called the top gate) electrode, and conductor 205 functions as the second gate (also called the back gate) electrode. It is also an insulator. 250 functions as the first gate insulator, and insulators 222 and 224 are the It functions as a gate insulator for 2. Also, the conductor 242a is one of the source or drain components. It functions as one of the two, and conductor 242b functions as the other of either the source or the drain. At least a portion of the region of the oxide 230 that overlaps with the conductor 260 is designated as a channel-forming region. It functions.

[0065] Here, Figure 4 shows an enlarged view of the vicinity of the channel formation region in Figure 3B. As shown in Figure 4... Furthermore, the oxide 230b forms region 23, which functions as a channel formation region of transistor 200. It is provided so as to sandwich region 0bc and region 230bc, and serves as either a source region or a drain region. It has functional regions 230ba and 230bb. Region 230bc is less In other words, region 230bc is superimposed on conductor 24 It is located in the region between 2a and the conductor 242b. Region 230ba is located between the conductor 242a It is provided superimposed on the conductor 242b, and region 230bb is provided superimposed on the conductor 242b. ru.

[0066] Region 230bc, which functions as a channel-forming region, is part of region 230ba and region 230 Because it has less oxygen deficiency or lower impurity concentration than bb, it has a lower carrier concentration and high resistance It is an anti-region. Also, region 230ba functions as a source region or drain region. The region 230bb has a high oxygen deficiency, or high concentrations of impurities such as hydrogen, nitrogen, and metallic elements. This region has a high degree of resistance, resulting in increased carrier concentration and lower resistance. That is, region 23. Regions 0ba and 230bb have higher carrier concentrations and lower resistance compared to region 230bc. It is a challenging area.

[0067] Here, the carrier concentration of the region 230bc that functions as the channel formation region is 1×10 18 cm -3 It is preferably below, and more preferably less than 1×10 17 cm -3 Even more preferably, it is less than 1×10 and even more preferably less than 1×10 16 cm -3 and even more preferably less than 1×10 13 cm -3 and even more preferably less than 1×10 12 cm -3 and even more preferably less than 1×10 Note that there is no particular limitation on the lower limit value of the carrier concentration of the region 230bc that functions as the channel formation region. For example, it can be 1×10 cm -9 cm -3

[0068] In addition, a region may be formed between the region 230bc and the region 230ba or the region 230bb, where the carrier concentration is equal to or lower than the carrier concentration of the regions 230ba and 230bb, and equal to or higher than the carrier concentration of the region 230bc. That is, the said region functions as the junction region between the region 230bc and the region 230ba or the region 230bb. The hydrogen concentration in the said junction region may be equal to or lower than the hydrogen concentration of the regions 230ba and 230bb, and equal to or higher than the hydrogen concentration of the region 230bc. Also, the oxygen deficiency in the said junction region may be equal to or less than the oxygen deficiency of the regions 230ba and 230bb, and equal to or more than the oxygen deficiency of the region 230bc.

[0069] ​​​​​​​​​In Figure 4, regions 230ba, 230bb, and 230bc are oxide 2. An example of formation in 30b is shown, but the present invention is not limited thereto. For example, each of the above regions may be formed not only on oxide 230b but also on oxide 230a. .

[0070] Furthermore, in oxide 230, it can sometimes be difficult to clearly detect the boundaries of each region. The concentrations of metallic elements, as well as impurity elements such as hydrogen and nitrogen, detected within each region are Furthermore, the changes may not be limited to gradual changes within each domain, but may also be continuous within each domain. The closer the region is to the channel formation region, the more likely it is to contain metallic elements, as well as hydrogen and nitrogen. It is sufficient if the concentration of impurity elements decreases.

[0071] Transistor 200 is made of oxide 230 (oxide 230a, and A metal oxide (hereinafter also called an oxide semiconductor) that functions as a semiconductor (230b) is added to the oxide. It is preferable to use .

[0072] Furthermore, metal oxides that function as semiconductors have a band gap of 2 eV or more, preferably It is preferable to use gold with a band gap of 2.5 eV or higher. By using a specific oxide, the off-current of the transistor can be reduced.

[0073] For example, In-M-Zn, which has indium, element M, and zinc as oxide 230. Oxides (elements M include aluminum, gallium, yttrium, tin, copper, vanadium, and beryllium) Rium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, ra Tantalum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium It is preferable to use one or more metal oxides selected from among others. For 230, In-Ga oxide, In-Zn oxide, or indium oxide may be used. .

[0074] Here, the atomic ratio of In to element M in the metal oxide used for oxide 230b However, the atomic ratio of In to element M in the metal oxide used in oxide 230a is larger It is preferable.

[0075] In this way, by placing oxide 230a below oxide 230b, oxide 230a Spread of impurities and oxygen to oxide 230b from structures formed below It can suppress dispersion.

[0076] Furthermore, oxides 230a and 230b have a common element other than oxygen (main component By (using this method), the defect level density at the interface between oxide 230a and oxide 230b is reduced. This can be done. The defect level density at the interface between oxide 230a and oxide 230b can be reduced. Because this can be achieved, the influence of interfacial scattering on carrier conduction is small, resulting in a high on-current. You can obtain this.

[0077] The oxide 230b is preferably crystalline. In particular, as the oxide 230b, C AAC-OS(c-axis aligned crystalline oxide It is preferable to use a semiconductor.

[0078] CAAC-OS has a highly crystalline, dense structure, and is free from impurities and defects (for example, It is a metal oxide with few oxygen deficiencies, etc. In particular, after the formation of the metal oxide, By heat-treating at a temperature that does not cause polycrystallization (for example, between 400°C and 600°C), This allows CAAC-OS to have a more crystalline and dense structure. By increasing the density of CAAC-OS, impurities or oxygen in the CAAC-OS can be removed. This can further reduce the spread of the virus.

[0079] On the other hand, CAAC-OS is difficult to identify clear grain boundaries, so it is difficult to identify grain boundaries. It can be said that a decrease in electron mobility due to CAAC-OS is less likely to occur. Metal oxides have stable physical properties. Therefore, metal oxides containing CAAC-OS are It is heat-resistant and highly reliable.

[0080] In transistors using oxide semiconductors, the region in the oxide semiconductor where the channel is formed... The presence of impurities and oxygen deficiencies can easily lead to variations in electrical properties and reduced reliability. Yes. Also, hydrogen near the oxygen vacancy can fill the oxygen vacancy, creating a defect (hereinafter referred to as V). O Let's call it H. In some cases, it forms an oxide, which can generate electrons that act as carriers. If an oxygen vacancy is present in the region where a channel is formed in a semiconductor, the transistor will not function properly. Mullion characteristics (a channel exists even when no voltage is applied to the gate electrode, and the transistor...) This makes it easy for current to flow. Therefore, channels are formed in oxide semiconductors. In the region, impurities, oxygen deficiencies, and V O H should preferably be reduced as much as possible. In other words, in the region where channels are formed in an oxide semiconductor, the carrier concentration is reduced. Therefore, it is preferable that it be type i (true) or substantially type i.

[0081] In contrast, near the oxide semiconductor, oxygen that is desorbed by heating (hereinafter referred to as excess oxygen) In some cases, an insulator containing ( ) is provided and heat treatment is performed, which can cause oxide semiconductors to be released from the insulator. It supplies oxygen to the body, prevents oxygen deficiency, and V O H can be reduced. However, the source region When an excess amount of oxygen is supplied to the region or drain region, the on current of transistor 200 This may cause a decrease in the source region, or a decrease in field-effect mobility. Furthermore, the source region Alternatively, the oxygen supplied to the drain region varies within the substrate surface, resulting in a transistor. This will result in variations in the characteristics of semiconductor devices.

[0082] Therefore, in the oxide semiconductor, the region 230bc that functions as a channel-forming region is The carrier concentration is reduced, and it is preferable that it is type i or substantially type i, but the source region Regions 230ba and 230bb, which function as a carrier or drain region, A high concentration and n-type are preferable. In other words, oxygen in the 230bc region of the oxide semiconductor. Missing, and V O Reduce H, and add an excess amount of oxygen to regions 230ba and 230bb. It is preferable to prevent the supply of [the substance].

[0083] Therefore, in this embodiment, conductor 242a and conductor 242b are placed on oxide 230b. With the setup in place, microwave treatment was performed in an oxygen-containing atmosphere, resulting in an oxygen deficiency in region 230bc. , and V O The aim is to reduce H. Here, microwave processing refers to using microwaves, for example. This refers to processing using a device equipped with a power supply that generates high-density plasma.

[0084] By performing microwave processing in an oxygen-containing atmosphere, microwaves or high frequencies such as RF are produced. By using this method, oxygen gas can be converted into plasma, and this oxygen plasma can be applied. It is also possible to irradiate the region 230bc with high-frequency waves such as microwaves or RF. Due to the effects of Zuma, microwaves, etc., the V region 230bc O By splitting H, hydrogen H is in region 2 Removed from 30bc, oxygen deficiency V O It can be supplemented with oxygen. In other words, region 230 In bc, "V O H → H + V O The following reaction occurs, and the hydrogen concentration in region 230bc changes It can be reduced. Therefore, the oxygen deficiency in region 230bc, and V O Reduce H, This can reduce the carrier concentration.

[0085] Furthermore, when performing microwave processing in an oxygen-containing atmosphere, high frequencies such as microwaves or RF are used. The effects of waves, oxygen plasma, etc., are shielded by conductors 242a and 242b, and the region It does not reach 230 ba and the 230 bb region. Furthermore, the effect of oxygen plasma is on oxides. Insulators 271a and 271 are provided covering 230b and the conductor 242. b and the insulator 280 can reduce this. This reduces the microwave processing At that time, in regions 230ba and 230bb, V O H reduction, and excess oxygen supply Since no supply is generated, a decrease in carrier concentration can be prevented.

[0086] In particular, after forming the insulating film that will become the insulator 250b, microwave treatment is performed in an oxygen-containing atmosphere. The above effects are significant. Further, after forming the insulating film that becomes the insulator 250a, microwave treatment is performed in an atmosphere containing oxygen, and after forming the insulating film that becomes the insulator 250b, microwave treatment is preferably performed in an atmosphere containing oxygen. By performing microwave treatment in an atmosphere containing oxygen through the insulator 250a or the insulator 250b in this way, oxygen can be efficiently injected into the region 230bc. Also, the oxygen injected into the region 230bc exists in various forms such as oxygen atoms, oxygen molecules, and oxygen radicals (atoms, molecules, or ions having unpaired electrons). Note that the oxygen injected into the region 230bc may be any one or more of the above forms, and is particularly preferably an oxygen radical. Also, since the film quality of the insulator 250a and the insulator 250b can be improved, the reliability of the transistor 200 is improved. After forming the insulating film that becomes the insulator 250a, microwave treatment is performed in an atmosphere containing oxygen, and after forming the insulating film that becomes the insulator 250b, microwave treatment is performed in an atmosphere containing oxygen. It is preferable. Thus, by performing microwave treatment in an atmosphere containing oxygen through the insulator 250a or the insulator 250b, oxygen can be efficiently injected into the region 230bc. Also, the oxygen injected into the region 230bc exists in various forms such as oxygen atoms, oxygen molecules, and oxygen radicals (atoms, molecules, or ions having unpaired electrons). Note that the oxygen injected into the region 230bc may be any one or more of the above forms, and is particularly preferably an oxygen radical. Also, since the film quality of the insulator 250a and the insulator 250b can be improved, the reliability of the transistor 200 is improved. After forming the insulating film that becomes the insulator 250a, microwave treatment is performed in an atmosphere containing oxygen, and after forming the insulating film that becomes the insulator 250b, microwave treatment is performed in an atmosphere containing oxygen. It is preferable. Thus, by performing microwave treatment in an atmosphere containing oxygen through the insulator 250a or the insulator 250b, oxygen can be efficiently injected into the region 230bc. Also, the oxygen injected into the region 230bc exists in various forms such as oxygen atoms, oxygen molecules, and oxygen radicals (atoms, molecules, or ions having unpaired electrons). Note that the oxygen injected into the region 230bc may be any one or more of the above forms, and is particularly preferably an oxygen radical. Also, since the film quality of the insulator 250a and the insulator 250b can be improved, the reliability of the transistor 200 is improved. After forming the insulating film that becomes the insulator 250a, microwave treatment is performed in an atmosphere containing oxygen, and after forming the insulating film that becomes the insulator 250b, microwave treatment is performed in an atmosphere containing oxygen.

[0087] In this way, oxygen deficiency and VH can be selectively removed in the region 230bc of the oxide semiconductor, and the region 230bc can be made into an i-type or substantially i-type. Further, excessive oxygen supply to the regions 230ba and 230bb that function as the source region or the drain region can be suppressed, and the n-type can be maintained. Thereby, the variation in the electrical characteristics of the transistor 200 can be suppressed, and the variation in the electrical characteristics of the transistor 200 within the substrate surface can be suppressed. O H is After forming the insulating film that becomes the insulator 250a, microwave treatment is performed in an atmosphere containing oxygen, and after forming the insulating film that becomes the insulator 250b, microwave treatment is performed in an atmosphere containing oxygen. It is preferable. Thus, by performing microwave treatment in an atmosphere containing oxygen through the insulator 250a or the insulator 250b, oxygen can be efficiently injected into the region 230bc. Also, the oxygen injected into the region 230bc exists in various forms such as oxygen atoms, oxygen molecules, and oxygen radicals (atoms, molecules, or ions having unpaired electrons). Note that the oxygen injected into the region 230bc may be any one or more of the above forms, and is particularly preferably an oxygen radical. Also, since the film quality of the insulator 250a and the insulator 250b can be improved, the reliability of the transistor 200 is improved. In this way, oxygen deficiency and VH can be selectively removed in the region 230bc of the oxide semiconductor, and the region 230bc can be made into an i-type or substantially i-type. Further, excessive oxygen supply to the regions 230ba and 230bb that function as the source region or the drain region can be suppressed, and the n-type can be maintained. Thereby, the variation in the electrical characteristics of the transistor 200 can be suppressed, and the variation in the electrical characteristics of the transistor 200 within the substrate surface can be suppressed.

[0088] By adopting the above configuration, a semiconductor device with little variation in transistor characteristics can be provided. Also, a semiconductor device with good reliability can be provided. Also, a semiconductor device having good electrical characteristics can be provided. After forming the insulating film that becomes the insulator 250a, microwave treatment is performed in an atmosphere containing oxygen, and after forming the insulating film that becomes the insulator 250b, microwave treatment is performed in an atmosphere containing oxygen. It is preferable. Thus, by performing microwave treatment in an atmosphere containing oxygen through the insulator 250a or the insulator 250b, oxygen can be efficiently injected into the region 230bc.

[0089] In addition, in Figure 3 and other figures, the side surface of the opening into which the conductor 260 is embedded is made of oxide 230b. Including the grooves, the shape is roughly perpendicular to the surface on which oxide 230b is formed, but in this embodiment The form is not limited to this. For example, the bottom of the opening has a gently curved surface, U The shape may be U-shaped. Also, for example, the side surface of the opening may be the surface to which oxide 230b is formed. It may be inclined in relation to [something].

[0090] Furthermore, as shown in Figure 3C, in a cross-sectional view of transistor 200 in the channel width direction, A curved surface may be present between the side surface of oxide 230b and the top surface of oxide 230b. The edges of the side surface and the edges of the top surface may be curved (hereinafter also referred to as rounded). .

[0091] The radius of curvature on the above curved surface is greater than 0 nm, and the oxide 2 in the region overlapping with conductor 242. A thickness smaller than 30b, or smaller than half the length of the region that does not have the curved surface. This is preferable. Specifically, the radius of curvature of the curved surface is greater than 0 nm and less than or equal to 20 nm. Preferably, the wavelength is 1 nm to 15 nm, and more preferably 2 nm to 10 nm. By adopting this shape, the oxide 230b of the insulator 250 and conductor 260 is formed. This can improve the coverage.

[0092] It is preferable that the oxide 230 has a laminated structure of multiple oxide layers with different chemical compositions. Specifically, in the metal oxide used in oxide 230a, the main component is the metal element. The atomic ratio of element M is the main component of the metal oxide used in oxide 230b. It is preferable that the atomic ratio of element M to the group elements is greater. Also, in oxide 230a In the metal oxide used, the atomic ratio of element M to In is used in oxide 230b. It is preferable that the atomic ratio of element M to In in the metal oxide is greater than that of In. In the metal oxide used in oxide 230b, the atomic ratio of In to element M is, The ratio of the number of atoms of In to element M in the metal oxide used in 230a is greater than the atomic ratio of In in the element M. preferable.

[0093] Furthermore, oxide 230b is preferably a crystalline oxide such as CAAC-OS. It seems that crystalline oxides such as CAAC-OS contain impurities and defects (such as oxygen deficiencies). It has a dense structure with low crystalline structure and low crystalline properties. Therefore, the source electrode or drain This makes it possible to suppress the extraction of oxygen from oxide 230b by the electrode. Furthermore, even when heat treatment is performed, the extraction of oxygen from oxide 230b can be reduced, The Rangista 200 is designed to withstand high temperatures (so-called thermal budget) during the manufacturing process. It is fixed.

[0094] Here, at the junction of oxide 230a and oxide 230b, the lower end of the conduction band is gently curved. It changes. In other words, the lower end of the conduction band at the junction of oxide 230a and oxide 230b is It can also be said that it changes continuously or joins continuously. In order to do this, acid Lowering the defect level density of the mixed layer formed at the interface between the oxide 230a and the oxide 230b good.

[0095] Specifically, oxide 230a and oxide 230b share a common element as their main component, in addition to oxygen. By having this, a mixed layer with a low density of defect levels can be formed. For example, for oxide 2 when 30b is an In-M-Zn oxide, as oxide 230a, an In-M-Zn oxide, an M-Zn oxide, an oxide of element M, an In-Zn oxide, an indium oxide, etc. can also be used. That's fine.

[0096] Specifically, as oxide 230a, a metal oxide with a composition of In:M:Zn = 1:3:4 [atomic ratio] or around that, or In:M:Zn = 1:1:0.5 [atomic ratio] or around that can be used. Also, as oxide 230b, a metal oxide with a composition of In:M:Zn = 1:1:1 [atomic ratio] or around that, or In:M:Zn = 4:2:3 [atomic ratio] or around that, or In:M:Zn = 5:1:3 [atomic ratio] or around that can be used. Note that the "around the composition" includes a range of ±30% of the desired atomic ratio. Also, as element M, it is preferable to use gallium. atomic ratio] or around that, or In:M:Zn = 5:1:3 [atomic ratio] or around that can be used. Note that the "around the composition" includes a range of ±30% of the desired atomic ratio. Also, as element M, it is preferable to use gallium. ratio. Also, as element M, it is preferable to use gallium.

[0097] When forming a film of the metal oxide by sputtering, the above atomic ratio is not limited to the atomic ratio of the formed metal oxide, and can also be the atomic ratio of the sputtering target used for forming the metal oxide. When forming a film of the metal oxide by sputtering, the above atomic ratio is not limited to the atomic ratio of the formed metal oxide, and can also be the atomic ratio of the sputtering target used for forming the metal oxide. That's fine.

[0098] By configuring oxide 230a and oxide 230b as described above, the density of defect levels at the interface between oxide 230a and oxide 230b can be lowered. Therefore, the influence on carrier conduction due to interface scattering is reduced, and transistor 200 can obtain a large on-current and high frequency characteristics. high frequency characteristics. That's fine.

[0099] Insulator 212, insulator 214, insulator 271, insulator 272, insulator 282, and insulating At least one of the edge members 283 is protected from impurities such as water and hydrogen entering from the substrate side or from the transition As a barrier insulating film that suppresses diffusion from above to transistor 200, It is preferable that this is possible. Therefore, insulator 212, insulator 214, insulator 271, insulation At least one of body 272, insulator 282, and insulator 283 contains hydrogen atoms, hydrogen molecules, Water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), copper atoms, etc. Using an insulating material that has the function of suppressing the diffusion of impurities (i.e., the above impurities do not easily permeate it) It is preferable to use oxygen (for example, at least one such as an oxygen atom or oxygen molecule). It is preferable to use an insulating material that has a function to suppress diffusion (i.e., one that is less permeable to the above-mentioned oxygen). It's nice.

[0100] In this specification, a barrier insulating film refers to an insulating film that has barrier properties. In this specification, barrier properties refer to the function of suppressing the diffusion of the corresponding substance (low permeability). (Also known as) capturing and fixing the corresponding substance (also known as gettering) (u) To be a function.

[0101] Insulator 212, insulator 214, insulator 271, insulator 272, insulator 282, and insulating The edge element 283 has the function of suppressing the diffusion of impurities such as water and hydrogen, as well as oxygen. It is preferable to use an insulator, such as aluminum oxide, magnesium oxide, or magnesium oxide. Phenium, gallium oxide, indium gallium zinc oxide, silicon nitride, or nitride acid Silicone can be used. For example, as insulator 212 and insulator 283. Therefore, it is preferable to use silicon nitride or the like, which has higher hydrogen barrier properties. Also, for example , as insulators 214, 271, 272, and 282, capture hydrogen. And using aluminum oxide or magnesium oxide, which have a high ability to fix hydrogen. It is preferable that this is done so that impurities such as water and hydrogen do not enter the insulator 212 and the insulator 2 Through 14, diffusion from the substrate side to the transistor 200 side can be suppressed. Alternatively, an interlayer insulating film in which impurities such as water and hydrogen are located outside the insulator 283. Therefore, diffusion towards transistor 200 can be suppressed. Alternatively, insulator 2 Oxygen contained in 24, etc., diffuses to the substrate side via insulators 212 and 214. This can be suppressed. Alternatively, oxygen contained in insulator 280, etc., insulator 2 This can suppress diffusion upwards from transistor 200 via components such as 82. In this way, transistor 200 suppresses the diffusion of impurities such as water and hydrogen, as well as oxygen. Functional insulators 212, 214, 271, 272, and 282 It is preferable to have a structure in which the elements are surrounded by an insulator 283.

[0102] Here, insulator 212, insulator 214, insulator 271, insulator 272, insulator 282, Furthermore, it is preferable to use an oxide having an amorphous structure as the insulator 283. For example, AlO x (x is any number greater than 0), or MgO y (y is any value greater than 0) It is preferable to use metal oxides such as (number). Gold having such an amorphous structure In genus oxides, oxygen atoms have dangling bonds, and in these dangling bonds... It may have the property of capturing or fixing hydrogen. Such amorphous structures A metal oxide is used as a component of transistor 200, or transistor 200 By placing it around the transistor 200, the hydrogen contained in transistor 200, or transistor 200 It can capture or fix hydrogen present in its surroundings. In particular, the transistor 200 It is preferable to capture or fix hydrogen contained in the channel-forming region. Amorphous structure A metal oxide having is used as a component of transistor 200, or transistor By placing it around 200, the transistor 200 has good characteristics and is highly reliable. It is possible to manufacture semiconductor devices.

[0103] Also, insulator 212, insulator 214, insulator 271, insulator 272, insulator 282, The insulator 283 is preferably amorphous, but may have a polycrystalline structure in some areas. A region may be formed. Also, insulator 212, insulator 214, insulator 271, insulator 272, insulator 282, and insulator 283 consist of an amorphous structure layer and a polycrystalline structure It may also be a multilayer structure in which layers are stacked. For example, multiple layers are stacked on top of an amorphous structure. A laminated structure in which layers of a crystalline structure are formed is also acceptable.

[0104] Furthermore, the insulator 272 may have a laminated structure. For example, the insulator 272 may be made of aluminum oxide A laminated structure of aluminum and silicon nitride formed on the aluminum oxide may also be used. By using a layered structure like this, a single layer of aluminum oxide or a single layer of silicon nitride is possible. This is preferable because it can further enhance barrier properties.

[0105] Insulator 212, Insulator 214, Insulator 216, Insulator 271, Insulator 272, Insulator 2 The deposition of films 80, insulator 282, insulator 283, and insulator 286 is, for example, by sputtering. It can be done using the sputtering method. The sputtering method does not require the use of hydrogen as the deposition gas. Insulator 212, Insulator 214, Insulator 216, Insulator 271, Insulator 272, Insulator 2 The hydrogen concentration of insulators 282, 283, and 286 can be reduced. It is possible. Furthermore, the film deposition method is not limited to sputtering; chemical vapor deposition (C) is also an option. VD (Chemical Vapor Deposition) method, molecular beam epitaxy (MBE: Molecular Beam Epitaxy) method, pulsed laser deposition (P LD:Pulsed Laser Deposition) method, atomic layer deposition (ALD:A Methods such as tomic layer deposition may be used as appropriate.

[0106] Furthermore, it is preferable to lower the resistivity of insulators 212 and 283. For example, the resistivity of insulator 212 and insulator 283 is approximately 1 × 10⁻⁶. 13 Ωcm By doing so, in the process of using plasma in the semiconductor device manufacturing process, the insulator 212, and And the insulator 283 is connected to the conductor 205, conductor 242, conductor 260, or conductor 246 Charge-up can sometimes be mitigated. Insulator 212 and Insulator 283 The resistivity is preferably 1 × 10⁻⁶ 10 Ωcm or more, 1 × 10 15 The density should be less than or equal to Ωcm.

[0107] Furthermore, insulators 216, 274, 280, and 286 are insulator 2 A dielectric constant lower than 14 is preferable. By using a material with a low dielectric constant as the interlayer film, wiring The parasitic capacitance that occurs between them can be reduced. For example, insulator 216, insulator 274, Silicon oxide, silicon oxide-nitride, and fluorine are added as the edge body 280 and the insulator 286. Silicon oxide, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen Alternatively, a suitable material such as silicon oxide with voids can be used.

[0108] The conductor 205 is positioned to overlap with the oxide 230 and the conductor 260. Therefore, it is preferable that the conductor 205 be embedded in an opening formed in the insulator 216. stomach.

[0109] The conductor 205 comprises conductor 205a, conductor 205b, and conductor 205c. The conductor 205a is provided in contact with the bottom surface and side wall of the opening. The conductor 205b is It is provided so as to be embedded in a recess formed in the conductor 205a. Here, the conductor 20 The upper surface of 5b is lower than the upper surface of the conductor 205a and the upper surface of the insulator 216. Conductor 2 05c is provided in contact with the upper surface of the conductor 205b and the side surface of the conductor 205a. Here, the height of the upper surface of the conductor 205c is the height of the upper surface of the conductor 205a and the insulator 216 It is approximately the same height as the top surface of conductor 205a and conductor 2. It will be configured to be enclosed within the 05c.

[0110] Here, conductors 205a and 205c are hydrogen atoms, hydrogen molecules, water molecules, and nitrogen atoms. Expansion of impurities such as atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), and copper atoms. It is preferable to use a conductive material that has the function of suppressing dispersion. Alternatively, oxygen (for example, Using a conductive material that has the function of suppressing the diffusion of at least one of the following: oxygen atoms, oxygen molecules, etc. It is preferable that they be present.

[0111] Conductive material having the function of reducing hydrogen diffusion in conductor 205a and conductor 205c By using this material, impurities such as hydrogen contained in the conductor 205b are removed from the insulator 224, etc. This prevents diffusion into oxide 230. Also, conductor 205a and By using a conductive material that has the function of suppressing oxygen diffusion in the conductor 205c, This can suppress the oxidation of the conductor 205b, which reduces its conductivity. Examples of conductive materials that have a suppressive function include titanium, titanium nitride, tantalum, and nitrogen. It is preferable to use tantalum oxide, ruthenium oxide, etc. The conductive material 205a can be a single layer or a multilayer of the above conductive material. For example, a conductor For 205a, titanium nitride can be used.

[0112] Furthermore, the conductor 205b is a conductive material mainly composed of tungsten, copper, or aluminum. It is preferable to use a material with properties. For example, tungsten can be used for the conductor 205b. stomach.

[0113] Conductor 205 may function as a second gate electrode. In that case, conductor 20 The potential applied to 5 is changed independently of the potential applied to the conductor 260, without being linked to it. This allows us to control the threshold voltage (Vth) of transistor 200. In particular, By applying a negative potential to the conductor 205, the Vth of transistor 200 can be increased. Therefore, it becomes possible to reduce the off-current. Thus, a negative potential is applied to the conductor 205. When applied, the voltage applied to the conductor 260 is greater than when not applied. The inductive current can be reduced.

[0114] Furthermore, the electrical resistivity of the conductor 205 is set considering the potential applied to the conductor 205. The thickness of the conductor 205 is measured and set to match the electrical resistivity. Also, the insulator 21 The film thickness of 6 will be approximately the same as that of conductor 205. Here, within the limits allowed by the design of conductor 205 It is preferable to reduce the film thickness of the conductor 205 and the insulator 216. By making it thinner, the absolute amount of impurities such as hydrogen contained in the insulator 216 is reduced. This allows for the reduction of the diffusion of the impurity into the oxide 230.

[0115] Furthermore, as shown in Figure 3A, the conductor 205 is made of the conductor 242a of oxide 230 and conductor It is preferable to provide a larger area than the area that does not overlap with the electric body 242b. In particular, as shown in Figure 3C. As such, the conductor 205 is at the channel width direction edges of oxide 230a and oxide 230b It is preferable that the region outside the part is also stretched. In other words, the oxide 230 On the outer side of the channel width direction, the conductor 205 and the conductor 260 are insulated. It is preferable that they are superimposed via a body. With this configuration, the first gate electrode and The electric field of conductor 260, which functions as a second gate electrode, and the electric field of conductor 205, which functions as a second gate electrode. The field allows the channel-forming region of oxide 230 to be electrically surrounded. In this model, the channel formation region is formed by the electric fields of the first gate and the second gate. The structure of transistors that are surrounded by air is called a surrounded channel (Sc This is called a hannel structure.

[0116] In this specification, etc., an S-channel transistor refers to a pair of gates. The electric fields of one and the other electrodes electrically surround the channel formation region. This represents the structure of the sta. Furthermore, the S-channel structure disclosed in this specification is a Fin-type structure. It differs from conventional and planar structures. By adopting an S-channel structure, short channels A transistor that is less susceptible to the Nell effect, or in other words, a transistor that is less prone to short-channel effects. It is possible.

[0117] Furthermore, as shown in Figure 3C, the conductor 205 is extended to function as wiring. However, this is not limited to the case where a conductor that functions as wiring is placed beneath the conductor 205. It is also possible to configure it in such a way. Furthermore, the conductor 205 is not necessarily provided one per transistor. There is no need to do so. For example, you can configure it so that the conductor 205 is shared by multiple transistors. stomach.

[0118] In transistor 200, the conductor 205 consists of conductor 205a, conductor 205b, The present invention is not limited to the above, but also to the configuration in which conductive material 205c is laminated. No. For example, the conductor 205 is provided as a single layer, two layers, or a laminated structure of four or more layers. It is also acceptable to use this configuration.

[0119] Insulators 222 and 224 function as gate insulators.

[0120] The insulator 222 suppresses the diffusion of hydrogen (for example, at least one such as a hydrogen atom or hydrogen molecule). It is preferable that it has a function to control oxygen. Also, the insulator 222 is oxygen (for example, oxygen atoms, It is preferable that the function suppresses the diffusion of at least one of the following: oxygen molecules. For example, Insulator 222 suppresses the diffusion of hydrogen and / or oxygen more effectively than insulator 224. It is preferable that it has a function.

[0121] The insulator 222 is made of either or both aluminum and hafnium, which are insulating materials. It is preferable to use an insulator containing an oxide. Suitable insulators include aluminum oxide and hafni oxide. Using oxides containing um, aluminum, and hafnium (hafnium aluminate), etc. It is preferable that such a material is used to form the insulator 222. 2 is the release of oxygen from the oxide 230 to the substrate side, and oxidation from the periphery of the transistor 200. It functions as a layer that suppresses the diffusion of impurities such as hydrogen into material 230. Therefore, insulator 222 By providing this feature, the diffusion of impurities such as hydrogen into the inside of transistor 200 is suppressed. This can suppress the formation of oxygen vacancies in the oxide 230. Also, the conductor 205 is an absolute This suppresses the reaction between the surrounding material 224 and the oxygen present in the oxide 230.

[0122] Alternatively, the above insulator may contain, for example, aluminum oxide, bismuth oxide, or germanium oxide. Niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, oxide Zirconium may be added. Alternatively, these insulators may be nitrided. Also, Insulator 222 is made of silicon oxide, silicon oxide nitride, or silicon nitride. They may be used in stacked form.

[0123] Furthermore, the insulator 222 may be, for example, aluminum oxide, hafnium oxide, tantalum oxide, Zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrT) (Io3), (Ba,Sr)TiO3 (BST), and other so-called high-k materials are included in the aqueous solution. The edge material may be used in a single layer or in a stacked configuration. As transistors become smaller and more integrated... Thinning the gate insulator can sometimes lead to problems such as leakage current. By using a high-k material as an insulator that functions as a body, the physical film thickness is maintained while... This makes it possible to reduce the gate potential during transistor operation.

[0124] The insulator 224 in contact with the oxide 230 is, for example, silicon oxide, silicon oxide nitride, etc. Use it as appropriate.

[0125] Furthermore, during the manufacturing process of transistor 200, the surface of oxide 230 is exposed. Therefore, heat treatment is preferable. This heat treatment is, for example, performed at a temperature of 100°C to 600°C. More preferably, the heating should be carried out at a temperature between 350°C and 550°C. The heat treatment is performed using nitrogen gas. Alternatively, an inert gas atmosphere, or an oxidizing gas at 10 ppm or more, 1% or more, The procedure should be carried out in an atmosphere containing 10% or more of the substance. For example, heat treatment is preferably carried out in an oxygen atmosphere. This supplies oxygen to oxide 230, thus eliminating oxygen deficiency V O This can help reduce it. Alternatively, the heat treatment may be carried out under reduced pressure. Or, the heat treatment may be carried out using nitrogen gas or an inert gas. After heat treatment in a gaseous atmosphere, an oxidizing gas is added at 10 ppm to replenish the desorbed oxygen. The above may be carried out in an atmosphere containing 1% or more, or 10% or more. Alternatively, an oxidizing gas may be used. After heat treatment in an atmosphere containing 0 ppm or more, 1% or more, or 10% or more, continuous nitrogen treatment Heat treatment may be carried out in an atmosphere of a primary gas or inert gas.

[0126] Furthermore, by performing an oxygenation treatment on oxide 230, the oxygen deficiencies in oxide 230 are supplied. It is repaired by the oxygen that is used, in other words, "V O This promotes the reaction "+O → null". Furthermore, the oxygen supplied reacts with the hydrogen remaining in oxide 230. This allows the hydrogen to be removed as H2O (dehydrated). This eliminates oxidation. The hydrogen remaining in substance 230 recombines with the oxygen vacancy and V O Suppresses the formation of H It is possible.

[0127] The insulators 222 and 224 may have a laminated structure of two or more layers. In that case, it is not limited to laminated structures made of the same material, but also applies to laminated structures made of different materials. Good. Also, the insulator 224 may be superimposed with the oxide 230a to form island-like structures. In total, the insulator 272 is in contact with the side surface of the insulator 224 and the top surface of the insulator 222. .

[0128] Oxide 243a and oxide 243b are provided on oxide 230b. 43a and oxide 243b are provided separated by the conductor 260.

[0129] Oxide 243 (oxide 243a and oxide 243b) is a material that suppresses oxygen permeation. It is preferable that it has the ability. Conductor 242 that functions as a source electrode and drain electrode and acid By placing an oxide 243, which has the function of suppressing oxygen permeation, between the oxide 230b and the oxide 230b, This is preferable because it reduces the electrical resistance between the conductor 242 and the oxide 230b. This configuration improves the electrical characteristics and reliability of transistor 200. The properties can be improved. Furthermore, the electrical resistance between the conductor 242 and the oxide 230b is sufficiently high. If the amount can be reduced, a configuration without oxide 243 may be used.

[0130] As oxide 243, a metal oxide containing element M may be used. In particular, element M is A Luminium, gallium, yttrium, or tin may be used. Oxide 243 is an oxide. It is preferable that the concentration of element M is higher than that of substance 230b. Also, as oxide 243, Gallium may be used. Alternatively, metal acids such as In-M-Zn oxide may be used as oxide 243. A compound may also be used. Specifically, in the metal oxide used in oxide 243, with respect to In The atomic ratio of element M in oxide 230b is the element relative to In in the metal oxide used in oxide 230b. It is preferable that the atomic ratio is greater than that of element M. Also, the film thickness of oxide 243 is 0.5 nm or less. Preferably, the upper part is 5 nm or less, more preferably 1 nm to 3 nm, and even more preferably 1 nm. The wavelength is between m and 2 nm. Furthermore, it is preferable that oxide 243 is crystalline. If 43 is crystalline, the release of oxygen from the oxide 230 can be effectively suppressed. For example, if oxide 243 has a crystalline structure such as hexagonal, then the acid in oxide 230 In some cases, it may be possible to suppress the release of primary substances.

[0131] The conductor 242a is provided in contact with the upper surface of the oxide 243a, and the conductor 242b is an oxide It is preferable that the conductors 242a and 242 are provided in contact with the upper surface of 243b. b functions as either the source electrode or the drain electrode of transistor 200, respectively.

[0132] Examples of conductors 242 (conductors 242a and 242b) include tantalum. Nitrides containing titanium, nitrides containing molybdenum, nitrides containing tungsten Materials, nitrides containing tantalum and aluminum, nitrides containing titanium and aluminum It is preferable to use such materials. In one embodiment of the present invention, a nitride containing tantalum is particularly Preferred. Also, for example, ruthenium oxide, ruthenium nitride, strontium and ruthenium Oxides containing lanthanum, oxides containing lanthanum and nickel, etc., may also be used. These materials Because it is a conductive material that is resistant to oxidation, or a material that maintains its conductivity even when it absorbs oxygen. ,preferable.

[0133] Furthermore, hydrogen contained in oxide 230b, etc., in conductor 242a or conductor 242b Diffusion may occur. In particular, conductors 242a and 242b contain nitrogen containing tantalum. By using the ion, the hydrogen contained in oxide 230b, etc., becomes conductor 242a or conductive It readily diffuses into body 242b, and the diffused hydrogen is present in either conductor 242a or conductor 242b. It can combine with nitrogen. In other words, hydrogen contained in oxides such as 230b is a conductor. It may be absorbed by 242a or conductor 242b.

[0134] Furthermore, a curved surface is not formed between the side surface of the conductor 242 and the top surface of the conductor 242. This is preferable. By using a conductor 242 in which the curved surface is not formed, the cross section in the channel width direction The cross-sectional area of ​​the conductor 242 on the surface can be increased. This allows the conductor 24 Since the resistance of 2 is reduced, the on-current of transistor 200 can be increased.

[0135] The insulator 271a is provided in contact with the upper surface of the conductor 242a, and the insulator 271b is It is provided in contact with the upper surface of the conductor 242b. Also, the upper surface of the insulator 271a is an insulator. It is preferable that the side surface of the insulator 271a is in contact with the insulator 250, while the side surface of the insulator 272 is in contact with the insulator 250. The upper surface of the edge 271b is in contact with the insulator 272, and the side surface of the insulator 271b is in contact with the insulator 250. It is preferable that the insulator 271 functions as at least a barrier insulating film against oxygen. It is preferable that the insulator 271 has the function of suppressing the diffusion of oxygen. This is preferable. For example, the insulator 271 has a function that suppresses oxygen diffusion more than the insulator 280. It is preferable to have the following. As the insulator 271, for example, silicon such as silicon nitride. A nitride containing [the specified element] can be used. In addition, the insulator 271 has the function of capturing impurities such as hydrogen. It is preferable that the insulator 271 has an amorphous structure. If an insulator such as a metal oxide, for example, aluminum oxide or magnesium oxide is used... Good. In particular, as the insulator 271, aluminum oxide having an amorphous structure, or By using amorphous aluminum oxide, hydrogen can be captured or solidified more effectively. This is preferable because it may be possible to attach it. This results in a reliable train with good characteristics. ZISTA 200 and semiconductor devices can be manufactured.

[0136] Insulator 272 consists of insulator 224, oxide 230a, oxide 230b, oxide 243, and conductive It is provided so as to cover the electric body 242 and the insulator 271. Hydrogen is used as the insulator 272. It is preferable that it has the function of capturing and fixing hydrogen. In that case, as the insulator 272 This refers to metal oxides having an amorphous structure, such as aluminum oxide or magnesium oxide. It is preferable that the material contains an insulator such as cium.

[0137] By providing the insulators 271 and 272 described above, a barrier property against oxygen is achieved. The conductor 242 can be wrapped in an insulator having the following properties: In other words, the insulator 224 and This prevents the oxygen contained in the insulator 280 from diffusing into the conductor 242. Therefore, the oxygen contained in insulators 224 and 280 directly affects the conductor 242. This can suppress the increase in resistivity and reduction in on-current that can occur due to oxidation.

[0138] Insulator 250 functions as a gate insulator. Insulator 250 is on top of oxide 230b It is preferable to arrange them in contact with the surface. The insulator 250 is silicon oxide, silicon oxide and nitride. silicon nitride oxide, silicon nitride, silicon oxide with added fluorine, carbon-added acid Silicon oxide, silicon oxide with added carbon and nitrogen, porous silicon oxide, etc. It can be used. In particular, silicon oxide and silicon oxide-nitride are stable to heat. Therefore, it is preferable.

[0139] Insulator 250, like insulator 224, has a concentration of impurities such as water and hydrogen in it. It is preferable that the amount is reduced. The film thickness of the insulator 250 is 1 nm or more and 20 nm or less. It is preferable to do so.

[0140] Furthermore, as shown in Figures 3B and 3C, when the insulator 250 has a two-layer laminated structure, The lower insulator 250a is formed using an insulator that is easily permeable to oxygen, and the upper insulator 25 It is preferable to form 0b using an insulator that has the function of suppressing oxygen diffusion. By using such a configuration, the oxygen contained in the insulator 250a diffuses into the conductor 260. This can suppress the decrease in the amount of oxygen supplied to oxide 230. This is possible. In addition, it suppresses the oxidation of the conductor 260 by oxygen contained in the insulator 250a. This is possible. For example, the insulator 250a can be used in place of the insulator 250 described above. The insulator 250b is made of either aluminum or hafnium. It is preferable to use an insulator containing an oxide of aluminum oxide. Oxides containing nium, aluminum, and hafnium (hafnium aluminate), etc. It is preferable to use it. Also, the film thickness of the insulator 250b should be 0.5 nm or more and 3.0 nm or less. Preferably, the wavelength is between 1.0 nm and 1.5 nm.

[0141] Furthermore, when silicon oxide or silicon oxide nitride is used as the lower layer of the insulator 250, The upper layer of body 250 may be made of an insulating material, which is a high-k material with a high dielectric constant. The gate insulator has a laminated structure of insulator 250a and insulator 250b, which helps to protect against heat. This allows for a stable and highly dielectric laminated structure. Therefore, the gate insulator This makes it possible to reduce the gate potential applied during transistor operation while maintaining the physical film thickness. Furthermore, it is possible to thin the equivalent oxide film thickness (EOT) of the insulator that functions as a gate insulator. This is the result.

[0142] Furthermore, a metal oxide may be provided between the insulator 250 and the conductor 260. The material preferably suppresses the diffusion of oxygen from the insulator 250 to the conductor 260. By providing a metal oxide that suppresses diffusion, the diffusion of oxygen from the insulator 250 to the conductor 260 is reduced. Dispersion is suppressed. In other words, the decrease in the amount of oxygen supplied to oxide 230 can be suppressed. Furthermore, the oxidation of the conductor 260 by oxygen in the insulator 250 can be suppressed.

[0143] Furthermore, even if the above metal oxide is configured to function as part of the first gate electrode, Good. For example, a metal oxide that can be used as oxide 230 is the same as the above metal oxide. It can be used in this way. In that case, the conductive material 260a is deposited by sputtering. Therefore, the electrical resistance of the above metal oxide can be reduced to make it a conductor. This is called OC( This can be called an Oxide Conductor electrode.

[0144] Having the above metal oxide, the influence of the electric field from the conductor 260 is not weakened. The on-current of the transistor 200 can be improved. Also, the insulator 250 and the above metal The physical thickness of the group oxide maintains the distance between the conductor 260 and the oxide 230. This makes it possible to suppress the leakage current between the conductor 260 and the oxide 230. Also, By providing a laminated structure of the insulator 250 and the metal oxide, the conductor 260 and the oxide The physical distance between object 230 and the conductor 260, and the electric field strength from the conductor 260 to the oxide 230. This can be easily adjusted as needed.

[0145] Conductor 260 functions as the first gate electrode of transistor 200. Conductor 26 0 comprises a conductor 260a and a conductor 260b disposed on top of the conductor 260a. Preferably, the conductor 260a encloses the bottom and sides of the conductor 260b. It is preferable to arrange them in this manner. Also, as shown in Figures 3B and 3C, the conductor 260 The upper surface of the conductive material is approximately the same as the upper surface of the insulator 250. Note that in Figures 3B and 3C, the conductive material is shown. Body 260 is shown as a two-layer structure of conductor 260a and conductor 260b, but it is a single-layer structure However, a laminated structure of three or more layers is also acceptable.

[0146] Conductor 260a contains hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules. It is preferable to use a conductive material that has the function of suppressing the diffusion of impurities such as copper atoms. Alternatively, a device that inhibits the diffusion of oxygen (for example, at least one such as an oxygen atom or oxygen molecule). It is preferable to use a conductive material that has conductivity.

[0147] Furthermore, because the conductor 260a has the function of suppressing oxygen diffusion, the insulator 250 The oxygen contained in the material suppresses the oxidation of the conductor 260b, which reduces its conductivity. Yes, it is possible. Examples of conductive materials that have the function of suppressing oxygen diffusion include titanium and nitride. Titanium, tantalum, tantalum nitride, ruthenium, ruthenium oxide, etc. are preferred. It's nice.

[0148] Furthermore, since the conductor 260 also functions as wiring, a highly conductive material should be used. This is preferable. For example, the conductor 260b is mainly composed of tungsten, copper, or aluminum. A conductive material can be used. Furthermore, the conductor 260b may also be in a laminated structure. For example, a laminated structure of titanium or titanium nitride and the above-mentioned conductive material may be used.

[0149] Furthermore, in transistor 200, the conductor 260 is formed on an insulator 280 or the like. The conductor 260 is formed in a self-aligning manner to fill the opening. Therefore, the conductor 260 is positioned in the region between the conductor 242a and the conductor 242b. It can be positioned reliably without any problems.

[0150] Furthermore, as shown in Figure 3C, in the channel width direction of transistor 200, the insulator 2 When the bottom surface of 22 is used as a reference, the conductor 260 and the oxide 230b overlap. The height of the bottom surface of the region that does not undergo this process is preferably lower than the height of the bottom surface of oxide 230b. The conductor 260, which functions as a electrode, transmits oxide 230b via an insulator 250, etc. By configuring the channel formation region to cover the sides and top surface, the electric field of the conductor 260 is oxidized. This makes it easier to apply the effect to the entire channel formation region of component 230b. Therefore, transistor 200 The on-current can be increased and the frequency characteristics can be improved. Based on the bottom surface of the insulator 222 When considered as a standard, the oxides 230a and 230b and the conductor 260 do not overlap. The difference between the height of the bottom surface of the conductor 260 and the height of the bottom surface of the oxide 230b in region i is, 0 nm to 100 nm, preferably 3 nm to 50 nm, more preferably 5 The range should be between 20 nm and 20 nm.

[0151] [Aperture area 400] The opening region 400 is formed by opening the insulator 282 during the semiconductor device manufacturing process. At this time, a recess may be formed in the insulator 280. After the opening region 400 is formed, By performing heat treatment, the oxygen contained in the insulator 280 and the hydrogen bonded with that oxygen are removed. It can be released to the outside through the opening region 400. Furthermore, hydrogen combined with oxygen can be released into water. It is then released. Therefore, it reduces unwanted oxygen and hydrogen contained in the insulator 280. It is possible. Also, the insulator 283 on the insulator 282 is within the opening region 400 of the insulator 280 It is provided so as to be in contact with the opening region 400, and on the insulator 283, there is an insulator 274 It is embedded. The depth of the recess in the insulator 280 is the depth of the insulator 280 in the semiconductor device. The thickness should be between 1 / 4 and 1 / 2 of the maximum film thickness.

[0152] The insulator 280 is provided on the insulator 272, and the insulator 250 and the conductor 260 are provided. An opening is formed in the area that is to be cut. Also, the upper surface of the insulator 280 is flattened. That's good too.

[0153] The insulator 280, which functions as an interlayer film, preferably has a low dielectric constant. By using the material as an interlayer film, parasitic capacitance between wiring can be reduced. Insulator 28 It is preferable that 0 be provided using a material similar to that of the insulator 216, for example. In particular, oxide Silicon oxide and silicon nitride are preferred because they are thermally stable. In particular, silicon oxide Materials such as silicon oxidnitride and silicon oxide with voids release oxygen upon heating. This is preferable because it allows for the easy formation of a region containing [the specified element].

[0154] The insulator 280 has reduced concentrations of impurities such as water and hydrogen. Preferred. For example, the insulator 280 is silicon such as silicon oxide or silicon oxide nitride. Any suitable oxides can be used.

[0155] The insulator 282 suppresses the diffusion of impurities such as water and hydrogen from above into the insulator 280. It is preferable that it functions as a barrier insulating film and has the function of capturing impurities such as hydrogen. It is preferable to do so. Furthermore, the insulator 282 is a barrier insulating film that suppresses oxygen permeation. It is preferable that it functions. The insulator 282 is a metal oxide having an amorphous structure. For example, an insulator such as aluminum oxide can be used. Insulator 212 and Insulator 283 Within the region sandwiched between them, it has the function of capturing impurities such as hydrogen in contact with the insulator 280. By providing the insulator 282, impurities such as hydrogen contained in the insulator 280 are captured. This allows the amount of hydrogen within that region to be kept constant. In particular, as an insulator 282 aluminum oxide having an amorphous structure, or aluminum oxide having an amorphous structure Using nium is preferable because it can sometimes capture or fix hydrogen more effectively. This results in a transistor 200 with good characteristics and high reliability, and semiconductor equipment A structure can be created.

[0156] The insulator 283 suppresses the diffusion of impurities such as water and hydrogen from above into the insulator 280. It functions as a barrier insulating film. Insulator 283 is placed on top of insulator 282. The edge material 283 is silicon nitride or silicon nitride oxide, or other silicon-containing nitride It is preferable to use a material. For example, an insulator 283 that is deposited by sputtering. Silicon nitride can be used. By depositing insulator 283 using the sputtering method, density It is possible to form a silicon nitride film with high rigidity and resistance to the formation of porosity, etc. As 283, on top of silicon nitride film deposited by sputtering, further ALD method The deposited silicon nitride films may be stacked. With such a structure, sputtering Even if defects such as voids occur in silicon nitride deposited by the AL method, the coating remains good. The voids are filled with silicon nitride film deposited by method D, thereby improving sealing performance. This is preferable because it allows for this.

[0157] The insulator 286 is provided on the insulator 283 and on the insulator 274.

[0158] Conductors 240a and 240b are primarily composed of tungsten, copper, or aluminum. It is preferable to use conductive materials as components. Also, conductor 240a and conductor 24 0b may be a layered structure.

[0159] Furthermore, when the conductor 240 is made into a laminated structure, the insulator 286, insulator 283, insulator 28 2. The conductors in contact with insulators 280, 272, and 271 contain water, hydrogen, etc. It is preferable to use a conductive material that has the function of suppressing the permeation of any impurities. For example, Using tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, ruthenium oxide, etc. It is preferable to have a conductive material that has the function of suppressing the permeation of impurities such as water and hydrogen. The material may be used in a single layer or a multilayer structure. Also, water and hydrogen contained in the layer above the insulator 283. These impurities are introduced into the oxide 230 through the conductors 240a and 240b. This can be suppressed.

[0160] Examples of insulators 241a and 241b include silicon nitride and aluminum oxide. Insulators such as um and silicon nitride can be used. Insulator 241a and Insulator 24 1b consists of insulators 286, 283, 282, 280, and 272. Since it is provided in contact with the insulator 271, it contains water, hydrogen and other insulators such as the insulator 280. This prevents the pure substance from mixing with the oxide 230 through the conductors 240a and 240b. This is possible. In particular, silicon nitride is preferred because it has high blocking properties for hydrogen. Yes. Also, the oxygen contained in the insulator 280 is absorbed by the conductors 240a and 240b. This can prevent it from happening.

[0161] Furthermore, the upper surfaces of the conductor 240a and the upper surfaces of the conductor 240b function as wiring. Conductors 246 (conductors 246a and conductors 246b) may be arranged. 46 uses a conductive material whose main component is tungsten, copper, or aluminum. This is preferable. The conductor may also be in a laminated structure, for example, titanium or titanium nitride. The tan and the conductive material may be laminated. The conductor is provided on the insulator. It may be formed to be embedded in the opening.

[0162] <Component materials for semiconductor devices> The following describes the constituent materials that can be used in semiconductor devices.

[0163] <<Substrate>> Examples of substrates for forming the transistor 200 include an insulating substrate, a semiconductor substrate, and A conductive substrate can be used. Examples of insulating substrates include glass substrates, quartz substrates, and Fire substrate, stabilized zirconia substrate (such as yttria-stabilized zirconia substrate), resin substrate There are plates and the like. Also, semiconductor substrates are made of materials such as silicon and germanium. Semiconductor substrates, or silicon carbide, silicon germanium, gallium arsenide, phosphate Examples include compound semiconductor substrates composed of zinc, zinc oxide, and gallium oxide. Furthermore, as mentioned above... A semiconductor substrate having an insulating region inside the semiconductor substrate, for example, SOI (Silicon Examples include on-insulator substrates. Conductive substrates include graphite substrates and metal substrates. These include alloy substrates, conductive resin substrates, etc. Alternatively, substrates containing metal nitrides, metal acids There are substrates containing monoxides, etc. Furthermore, there are substrates on which a conductor or semiconductor is provided on an insulating substrate. A substrate, a semiconductor substrate provided with a conductor or insulator, a conductive substrate provided with a semiconductor or insulator There are substrates with edges provided. Alternatively, substrates on which elements are provided can be used. This may also be done. The elements provided on the substrate may include capacitive elements, resistive elements, switching elements, and light-emitting elements. These include children, memory elements, etc.

[0164] <<Insulator>> Insulators include insulating oxides, nitrides, oxidized nitrides, nitride oxides, and metal oxides. Examples include metal oxides, metal nitrides, and metal nitride oxides.

[0165] For example, as transistors become smaller and more integrated, the gate insulator can be made thinner. This can lead to problems such as leakage current. By using high-k materials, the physical film thickness is maintained while lowering the voltage during transistor operation. This becomes possible. On the other hand, for the insulator that functions as an interlayer film, a material with a low dielectric constant is used. This reduces parasitic capacitance between wires. Therefore, it is possible to reduce the parasitic capacitance that occurs between wires. Then, you should select the materials.

[0166] Furthermore, insulators with high dielectric constants include gallium oxide, hafnium oxide, and zirconium oxide. Oxides containing aluminum, aluminum, and hafnium, aluminum and hafnium Oxidized nitrides, silicon and hafnium oxides, silicon and hafnium Examples include oxide nitrides containing um, or nitrides containing silicon and hafnium.

[0167] Furthermore, as insulators with low dielectric constant, silicon oxide, silicon oxide nitride, and fluorine are used. Silicon oxide with added carbon, silicon oxide with added carbon and nitrogen Examples include silicon oxide with voids, or resins.

[0168] Furthermore, transistors using metal oxides suppress the permeation of impurities such as hydrogen and oxygen. By surrounding it with an insulator that has the function of stabilizing the electrical characteristics of the transistor. This is possible. As an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen, For example, boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, Phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum An insulator containing fluorine, neodymium, hafnium, or tantalum is used in a single layer or in a multilayer structure. That's all that's needed. Specifically, an insulating material that has the function of suppressing the permeation of impurities such as hydrogen and oxygen. As a body, aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, acid Yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, acid Metal oxides such as tantalum oxide, aluminum nitride, silicon nitride, silicon nitride, etc. Metal nitrides can be used.

[0169] Furthermore, the insulator that functions as a gate insulator has regions containing oxygen that is released by heating. It is preferable that the insulator has a region containing oxygen that is desorbed by heating. By creating a structure in which silicon oxide or silicon oxide nitride is in contact with oxide 230, This can compensate for the oxygen deficiency present in 230.

[0170] <<Conductive material>> Examples of conductive materials include aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, and crystalline silver. Tun, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium Zium, zirconium, beryllium, indium, ruthenium, iridium, strontium A metallic element selected from um, lanthanum, etc., or an alloy containing the aforementioned metallic elements. It is preferable to use an alloy or the like that which combines the above-mentioned metal elements. For example, tantalum nitride Titanium nitride, tungsten, nitrides containing titanium and aluminum, tantalum and aluminum Nitrides containing ruthenium, ruthenium oxide, ruthenium nitride, strontium and ruthenium It is preferable to use oxides containing lanthanum and nickel. Tantalum, titanium nitride, titanium and aluminum nitrides, tantalum and aluminum Includes nitrides, ruthenium oxide, ruthenium nitride, strontium and ruthenium oxides Oxides containing lanthanum and nickel are conductive materials that are resistant to oxidation, or that absorb oxygen. It is preferable because it is a material that maintains conductivity even when subjected to certain conditions. Furthermore, it does not contain impurity elements such as phosphorus. Highly electrically conductive semiconductors such as polycrystalline silicon and nickel silicides. Silicide may also be used.

[0171] Furthermore, multiple conductive layers formed from the above materials may be stacked and used. For example, as described above. A laminated structure may be formed by combining a material containing a metallic element with a conductive material containing oxygen. Furthermore, a laminate combining the aforementioned metal element-containing material and a nitrogen-containing conductive material is also used. It may also be used as a structure. Furthermore, a material containing the aforementioned metal element, a conductive material containing oxygen, and nitrogen A laminated structure combining conductive materials containing elements may also be used.

[0172] Furthermore, when an oxide is used in the channel formation region of a transistor, the gate electrode and A conductor that functions as such includes a material containing the aforementioned metal element and a conductive material containing oxygen. It is preferable to use a combined laminated structure. In this case, an oxygen-containing conductive material is used. It is preferable to place it on the channel formation region side. A conductive material containing oxygen should be placed on the channel formation region side. This makes it easier for oxygen released from the conductive material to be supplied to the channel-forming region.

[0173] In particular, as a conductor that functions as a gate electrode, it is included in the metal oxide in which the channel is formed. It is preferable to use a conductive material containing metallic elements and oxygen. Conductive materials containing group elements and nitrogen may be used. For example, titanium nitride, tantalum nitride Conductive materials containing nitrogen, such as indium tin oxide and tungsten oxide, may also be used. Indium oxide containing tungsten, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide containing titanium dioxide, indium tin oxide containing titanium dioxide, indium zinc oxide Indium tin oxide with added silicon may also be used. Moogarium zinc oxide may also be used. Using such a material allows for channel formation. In some cases, hydrogen contained in the metal oxide can be captured. Alternatively, the outer atmosphere In some cases, it may be possible to capture hydrogen that has been introduced from surrounding materials.

[0174] <<Metal Oxides>> As oxide 230, a metal oxide (oxide semiconductor) that functions as a semiconductor is used. This is preferable. Below, metal oxides applicable to the oxide 230 according to the present invention will be described. do.

[0175] The metal oxide preferably contains at least indium or zinc. In particular, indium Preferably, it contains aluminum and zinc. In addition, aluminum and gallium It is preferable that it contains yttrium, tin, etc. Also, boron, titanium, iron, nitrile Germanium, Zirconium, Molybdenum, Lanthanum, Cerium, Neodymium, Ha One of the following materials is selected from tungsten, tantalum, magnesium, cobalt, etc. It may include multiple species.

[0176] Here, the metal oxide is In-M-Zn oxide, which has indium, element M, and zinc. Let's consider the case where it is a substance. Note that element M is aluminum, gallium, yttrium, and Let M be tin. Other elements that can be used for element M include boron, titanium, iron, and nickel. Germanium, Zirconium, Molybdenum, Lanthanum, Cerium, Neodymium, Hafnium Examples include um, tantalum, tungsten, magnesium, and cobalt. However, element M and Furthermore, it is sometimes acceptable to combine multiple of the aforementioned elements.

[0177] In this specification, metal oxides containing nitrogen are also referred to as metal oxides (metal oxides). They are sometimes collectively referred to as ide. Also, metal oxides containing nitrogen are called metal oxide nitrides (m It may also be called etal oxynitride.

[0178] <Classification of crystal structures> First, we will explain the classification of crystal structures in oxide semiconductors using Figure 5A. Figure 5A shows an oxide semiconductor, typically IGZO (containing metal acids such as In, Ga, and Zn). This is a diagram illustrating the classification of the crystal structures of ionized compounds.

[0179] As shown in Figure 5A, oxide semiconductors can be broadly classified into "Amorphous" It is divided into "Crystalline (crystalline)" and "Crystal (crystal)". They are classified as such. Also, among "Amorphous," there are completely amorp It includes hous. Also, within "Crystalline" there is CAAC(c-ax is-aligned crystalline), nc(nanocrystalli ne), and CAC (cloud-aligned composite) are included. excluding single crystal and poly crystal l). Note that the classification of "Crystalline" includes single crystal, Polycrystalline and completely amorphous materials are excluded. Furthermore, within "Crystal," there are single crystals and poly crystals. It contains crystal.

[0180] The structures within the thick border shown in Figure 5A are "Amorphous" and "Cry It is an intermediate state between "stal (crystal)" and a new boundary region (New crystal This structure belongs to the line phase. In other words, this structure is energetically in It is completely different from the stable "Amorphous" or "Crystal" forms. This can be rephrased as a structure.

[0181] The crystal structure of the film or substrate can be determined by X-ray diffraction (XRD). It can be evaluated using the ion spectrum. Here, "Crystalline GIXD (Grazing-Incidence) of CAAC-IGZO film, which is classified as " The XRD spectrum obtained by the XRD measurement is shown in Figure 5B. Note that the GIXD method is used for thin films. This method is also called the Seemann-Bohlin method. Hereafter, the GIXD measurement shown in Figure 5B will be used. The resulting XRD spectrum will simply be referred to as the XRD spectrum. Note that the CAA shown in Figure 5B The composition of the C-IGZO film is approximately In:Ga:Zn = 4:2:3 [atomic ratio]. The thickness of the CAAC-IGZO film shown in Figure 5B is 500 nm.

[0182] As shown in Figure 5B, the XRD spectrum of the CAAC-IGZO film clearly shows crystallinity. The peak shown is detected. Specifically, in the XRD spectrum of the CAAC-IGZO film, A peak indicating c-axis orientation is detected near 2θ = 31°. Furthermore, as shown in Figure 5B, The peak near 2θ=31° is located at the angle where the peak intensity was detected. It is asymmetrical.

[0183] Furthermore, the crystal structure of the film or substrate is determined by nano-beam diffraction (NBED). Diffraction patterns observed by electron diffraction (extremely small) It can be evaluated by (also called electron diffraction pattern). The folding pattern is shown in Figure 5C. Figure 5C shows an NBED with an electron beam incident parallel to the substrate. This is the diffraction pattern observed by the CAAC-IGZO film shown in Figure 5C. The composition is approximately In:Ga:Zn=4:2:3 [atomic ratio]. Furthermore, micro-electron diffraction... Next, electron diffraction is performed with a probe diameter of 1 nm.

[0184] As shown in Figure 5C, the diffraction pattern of the CAAC-IGZO film shows multiple c-axis orientations. Spots of this nature are observed.

[0185] <<Oxide semiconductor structure>> Note that oxide semiconductors may be classified differently from those shown in Figure 5A when considering their crystal structure. Yes, there are. For example, oxide semiconductors include single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. It can be divided into two parts. Examples of non-single-crystal oxide semiconductors include the aforementioned CAAC-OS. And there is nc-OS. In addition, non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors and pseudo-non-crystalline oxide semiconductors. crystalline oxide semiconductor (a-like OS: amorphous-like oxide) This includes semiconductors, amorphous oxide semiconductors, and so on.

[0186] Here, we will provide details on the CAAC-OS, nc-OS, and a-like OS mentioned above. Then, I will give an explanation.

[0187] [CAAC-OS] CAAC-OS has multiple crystalline regions, and the c-axis of these crystalline regions is oriented in a specific direction. It is an oriented oxide semiconductor. The specific direction refers to the thickness direction of the CAAC-OS film. , in the direction normal to the surface on which the CAAC-OS film is formed, or in the direction normal to the surface of the CAAC-OS film Yes, there is. Furthermore, a crystalline region is a region in which the atomic arrangement has periodicity. Note that the atomic arrangement is categorized If considered as a child arrangement, a crystalline region is also a region with a aligned lattice arrangement. Furthermore, CAAC- OS has a region in which multiple crystal regions are connected in the ab-plane direction, and this region is strained It may have strain. Note that strain refers to the lattice arrangement in a region where multiple crystal regions are connected. The orientation of the grid arrangement changes between a region with aligned grids and another region with aligned grids. This refers to the location. In other words, CAAC-OS is c-axis oriented and has a clear orientation in the ab-plane direction. It is an oxide semiconductor that does not exist.

[0188] Each of the above multiple crystalline regions is composed of one or more minute crystals (with a maximum diameter of 10 It is composed of crystals smaller than nm. Furthermore, the maximum diameter of the crystalline region is less than 10 nm. If this occurs, the size of the crystalline region may be around several tens of nanometers.

[0189] Also, In-M-Zn oxide (element M is aluminum, gallium, yttrium, sulfite) In one or more types selected from materials such as titanium, CAAC-OS is an indicator. A layer containing um (In) and oxygen (hereinafter referred to as the In layer), and an element M, zinc (Zn), and acid A layered crystalline structure (also called a layered structure) is formed by stacking layers containing an element (hereinafter referred to as (M,Zn) layer). It tends to have (u). Furthermore, indium and element M are mutually substitutable. Therefore The (M,Zn) layer may contain indium. Also, the In layer contains element M. This may occur. Furthermore, the In layer may also contain Zn. This layered structure is, for example, In high-resolution TEM images, it is observed as a grid pattern.

[0190] For example, when structural analysis of a CAAC-OS film is performed using an XRD device, the θ / 2θ scale is obtained. Out-of-plane XRD measurements using the CANR showed two peaks indicating c-axis orientation. It is detected at θ=31° or nearby. Note that the position of the peak indicating c-axis orientation (value of 2θ) ) may vary depending on the type and composition of the metal elements that make up CAAC-OS.

[0191] Furthermore, for example, in the electron diffraction pattern of a CAAC-OS film, multiple bright spots (spots) (T) is observed. Note that one spot and another spot are separated by the incident electron beam that has passed through the sample. With the spot (also called the direct spot) as the center of symmetry, observations are made at point-symmetric positions. It can be done.

[0192] When the crystal region is observed from the specific direction described above, the lattice arrangement within that crystal region is a hexagonal lattice. While this is the basic principle, the unit cell is not necessarily a regular hexagon and may be a non-regular hexagon. Also, The above distortion may have a grid arrangement such as a pentagon or heptagon. -In OS, clear grain boundaries were confirmed even near the strain. This is not possible. In other words, the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This indicates that CAAC-OS has a dense arrangement of oxygen atoms in the ab-plane direction. This is because, for example, the substitution of metal atoms changes the bond distance between atoms. This is thought to be because it allows for distortion to be tolerated.

[0193] Furthermore, a crystal structure in which clear grain boundaries can be observed is known as a polycrystalline structure. It is called al(al). The grain boundaries become recombination centers, trapping carriers and forming transistors. This is likely to cause a decrease in on-current and a decrease in field-effect mobility. CAAC-OS, which lacks visible grain boundaries, has a crystal structure suitable for the semiconductor layer of transistors. It is one of the crystalline oxides that possesses Zn. Furthermore, CAAC-OS requires the presence of Zn. A configuration in which In-Zn oxide and In-Ga-Zn oxide are made of In acid It is preferable because it can suppress the generation of grain boundaries more effectively than oxidized materials.

[0194] CAAC-OS is an oxide semiconductor with high crystallinity and no clearly defined grain boundaries. Therefore, CAAC-OS is less prone to a decrease in electron mobility caused by grain boundaries. Furthermore, the crystallinity of oxide semiconductors can decrease due to impurities and the formation of defects. Because of this, CAAC-OS is an oxide semiconductor with few impurities and defects (such as oxygen vacancies) It can also be said that oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. C-OS is stable even at high temperatures (so-called thermal budget) during the manufacturing process. Therefore, using CAAC-OS in OS transistors expands the degree of freedom in the manufacturing process. It becomes possible to increase the risk.

[0195] [nc-OS] nc-OS is used in minute regions (for example, regions between 1 nm and 10 nm, especially regions larger than 1 nm). It has periodicity in the atomic arrangement in the region of 3 nm or less. In other words, nc-OS is micro It has small crystals. The size of these minute crystals is, for example, between 1 nm and 10 nm. In particular, because they are between 1 nm and 3 nm in size, these minute crystals are also called nanocrystals. Furthermore, nc-OS shows no regularity in crystal orientation between different nanocrystals. Therefore, the entire film... No orientation is observed. Therefore, nc-OS is a-like depending on the analytical method. It can sometimes be indistinguishable from OS or amorphous oxide semiconductors. For example, compared to nc-OS films When performing structural analysis using an XRD device, out-of-pl using θ / 2θ scans is obtained. In ane XRD measurements, no peak indicating crystallinity was detected. Furthermore, for nc-OS films... Furthermore, electron beam blasts using electron beams with probe diameters larger than those of nanocrystals (e.g., 50 nm or more) When diffraction (also called limited-field electron diffraction) is performed, a diffraction pattern similar to a halo pattern is obtained. Observed. On the other hand, compared to the nc-OS film, the size is close to or smaller than that of nanocrystals. Electron diffraction (nanobeam) using electron beams with probe diameters (e.g., 1 nm to 30 nm). Also called electron diffraction, when this is performed, a ring-shaped region centered on the direct spot appears. In some cases, electron diffraction patterns with multiple spots observed may be obtained.

[0196] [a-like OS] a-like OS is an oxide having a structure between nc-OS and amorphous oxide semiconductors. It is a semiconductor. an a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS. Also, it has a-like properties. OS has a higher hydrogen concentration in the membrane compared to nc-OS and CAAC-OS.

[0197] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS is a material composition. Regarding achievement.

[0198] [CAC-OS] CAC-OS refers to, for example, metal oxides in which the elements constituting the metal oxide are between 0.5 nm and 10 nm. Below, preferably, a structure of material that is unevenly distributed with a size of 1 nm to 3 nm or near that size. It is formed. Furthermore, in the following, in metal oxides, one or more metal elements are unevenly distributed. The region containing the metal element is 0.5 nm to 10 nm, preferably 1 nm to 3 nm. A mixture of particles smaller than or near a m in size is also called a mosaic or patchy appearance. .

[0199] Furthermore, CAC-OS is a material that separates into a first region and a second region. This results in a zigzag-like structure, where the first region is distributed within the film (hereinafter also referred to as a cloud-like structure). ) In other words, CAC-OS is a mixture of the first region and the second region. It is a composite metal oxide having the following composition.

[0200] Here, I for the metal elements constituting CAC-OS in In-Ga-Zn oxide The atomic ratios of n, Ga, and Zn are given as [In], [Ga], and [Zn] respectively. To be expressed. For example, in CAC-OS in In-Ga-Zn oxide, the first region This is the region where [In] is greater than the [In] in the composition of the CAC-OS film. The second region is the region where [Ga] is greater than the [Ga] in the composition of the CAC-OS film. That is. Or, for example, in the first region, [In] is greater than [In] in the second region. It is also a region where the [Ga] is large, and the [Ga] is smaller than the [Ga] in the second region. Furthermore, in the second region, [Ga] is greater than [Ga] in the first region, and [I n] is a region where n is smaller than [In] in the first region.

[0201] Specifically, the first region mentioned above mainly consists of indium oxide, indium zinc oxide, etc. This is a region of minutes. Furthermore, the second region mentioned above is gallium oxide, gallium zinc oxide, etc. This is the region in which In is the main component. In other words, the first region described above can be said to be the region in which In is the main component. It can be replaced. Furthermore, the second region described above can be rephrased as the region with Ga as the main component. It is possible.

[0202] Note that a clear boundary may not be observed between the first region and the second region described above. .

[0203] For example, in CAC-OS in In-Ga-Zn oxide, the energy-dispersive X-ray segment Optical method (EDX:Energy Dispersive X-ray spectrosc) EDX mapping obtained using opy revealed the region with In as its main component (the first region) It has a structure in which a region (the second region) and a region mainly composed of Ga are unevenly distributed and mixed. This can be confirmed.

[0204] When CAC-OS is used in a transistor, the conductivity is due to the first region and the second region The insulating properties due to the region work complementarily to enable the switching function (On The function to turn off CAC-OS can be added to it. In other words, CAC-OS and The material has both conductive and insulating properties in parts, and the entire material Then it has the function of a semiconductor. By separating the conductive function and the insulating function, This allows for the maximum enhancement of both functions. Therefore, CAC-OS is used in transistors. This results in a high on-current (I on ), high field-effect mobility (μ), and good switching This enables smooth operation.

[0205] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention Oxide semiconductors include amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, and C It may have two or more of the following: AC-OS, nc-OS, and CAAC-OS.

[0206] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0207] By using the above oxide semiconductor in a transistor, a transistor with high field-effect mobility is obtained. This can be achieved. Furthermore, highly reliable transistors can be realized.

[0208] A low-carrier-concentration oxide semiconductor is used in the channel formation region of the transistor. This is preferable. For example, the carrier concentration in the channel formation region of the oxide semiconductor is 1 × 10⁻⁶. 17 c m -3 The following is preferably 1 × 10 15 cm -3 More preferably 1 × 10 13 cm -3 More preferably 1 × 10 11 cm -3 More preferably 1 × 10 10 c m -3 It is less than 1 × 10 -9 cm -3 That concludes the explanation. Note that the carriers in oxide semiconductor films... When lowering the concentration, the impurity concentration in the oxide semiconductor film is reduced, and the defect level density is lowered. It is sufficient to lower the value. In this specification, etc., a low impurity concentration and a low defect level density are used. This is referred to as high-purity intrinsic or substantially high-purity intrinsic. Furthermore, oxide semiconductors with low carrier concentrations are... These are sometimes referred to as high-purity intrinsic or substantially high-purity intrinsic oxide semiconductors.

[0209] Furthermore, oxide semiconductor films that are high-purity intrinsic or substantially high-purity intrinsic have a low defect level density. Therefore, the trap level density may also be low.

[0210] Furthermore, the time required for charges trapped in the trap levels of an oxide semiconductor to disappear is also important. It can behave for a long time, almost like a fixed charge. Therefore, the trap level density is high. Transistors in which a channel formation region is formed in an oxide semiconductor have unstable electrical properties. There are cases where this occurs.

[0211] Therefore, in order to stabilize the electrical characteristics of a transistor, the impurity concentration in the oxide semiconductor is Reducing it is effective. Furthermore, in order to reduce the impurity concentration in oxide semiconductors, It is also preferable to reduce the concentration of impurities in the adjacent membrane. Examples of impurities include hydrogen, nitrogen, and Examples include potassium metals, alkaline earth metals, iron, nickel, and silicon.

[0212] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0213] In oxide semiconductors, if silicon or carbon, which are among the Group 14 elements, are present, oxidation occurs. Defect levels are formed in material semiconductors. Therefore, in the channel formation region of oxide semiconductors... The concentrations of silicon and carbon, for example, the insulator, and the channel formation region of the oxide semiconductor. The concentrations of silicon and carbon at the interface and near the interface (by secondary ion mass spectrometry (SIMS)). Concentration obtained by econdary ion mass spectrometry ) to 2 × 10 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0214] Furthermore, if alkali metals or alkaline earth metals are present in the oxide semiconductor, defect levels are formed. This can result in the generation of carriers. Therefore, alkali metals or alkaline earth metals may be present. Transistors using oxide semiconductors tend to exhibit normally-on characteristics. Therefore, alkali metals or a in the channel formation region of oxide semiconductors obtained by SIMS The concentration of rutile earth metals is 1 × 10⁻⁶ 18 atoms / cm 3 The following is preferably 2 × 10 1 6 atoms / cm 3 Do the following:

[0215] Furthermore, in oxide semiconductors, when nitrogen is present, electrons, which are carriers, are generated. As the nitrogen concentration increases, it becomes easier to convert to n-type semiconductors. As a result, oxide semiconductors containing nitrogen become semiconductors. The transistor used tends to exhibit normally-on characteristics. Alternatively, oxide semiconductors Furthermore, when nitrogen is present, trap levels may be formed. As a result, transistor The electrical properties of the oxide semiconductor obtained by SIMS may become unstable. The nitrogen concentration in the channel formation region is 5 × 10 19 atoms / cm 3 The following, preferably 5 x 10 19 atoms / cm 3 Less than 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0216] Furthermore, the hydrogen contained in oxide semiconductors reacts with the oxygen bonded to the metal atoms to form water. Therefore, an oxygen deficiency may form. When hydrogen enters this oxygen deficiency, the carrier electrons In some cases, a child may be produced. Also, some of the hydrogen combines with the metal atom and oxygen, resulting in a crystal. It can generate electrons that act as carriers. Therefore, an oxide semiconductor containing hydrogen is used. Transistors that have been modified tend to exhibit normally-on characteristics. For this reason, the channels of oxide semiconductors It is preferable that the amount of hydrogen in the hydrogen-forming region be reduced as much as possible. Specifically, In the channel formation region of an oxide semiconductor, the hydrogen concentration obtained by SIMS is 1 × 1 0 20 atoms / cm 3 Less than 5 × 10 19 atoms / cm 3 Less than, Preferably 1 × 10 19 atoms / cm 3 Less than 5 × 10 18 ato ms / cm 3 Less than 1 × 10 18 atoms / cm 3 Make it less than.

[0217] Using an oxide semiconductor with sufficiently reduced impurities in the channel formation region of a transistor. This allows for the provision of stable electrical characteristics.

[0218] <<Other Semiconductor Materials>> The semiconductor materials that can be used for oxide 230 are not limited to the metal oxides mentioned above. As monster 230, semiconductor materials with a band gap (not zero-gap semiconductors) Conductive materials may be used. For example, semiconductors of elemental silicon, gallium arsenide, etc. Which compound semiconductors, layered materials that function as semiconductors (also known as atomic layer materials, two-dimensional materials, etc.) It is preferable to use materials such as (u) as semiconductor materials. In particular, layered materials that function as semiconductors It is preferable to use this as a semiconductor material.

[0219] Here, in this specification, etc., "layered material" is a general term for a group of materials having a layered crystalline structure. Yes, it exists. Layered crystal structures are formed by layers created by covalent or ionic bonds, such as van der Wa. It is a structure in which layers are attached via weaker bonds than covalent or ionic bonds, such as the Ruhls force. Layered materials have high electrical conductivity within a single layer, meaning they have high two-dimensional electrical conductivity. A material that functions as a semiconductor and has high two-dimensional electrical conductivity is used in the channel formation region. This makes it possible to provide transistors with a large on-current.

[0220] Examples of layered materials include graphene, silicene, and chalcogenides. It is a compound containing chalcogens. Furthermore, chalcogens are a general term for elements belonging to Group 16. It contains oxygen, sulfur, selenium, tellurium, polonium, and livermorium. Examples of chalcogenides include transition metal chalcogenides and group 13 chalcogenides. .

[0221] For example, a transition metal chalcogenide that functions as a semiconductor can be used as oxide 230. Preferably, a transition metal chalcogenide applicable as oxide 230 is specified. These include molybdenum sulfide (typically MoS2) and molybdenum selenide (typically MoS2) e2), molybdenum tellurium (typically MoTe2), tungsten sulfide (typically W S2), tungsten selenide (typically WSe2), tungsten tellurium (typically (WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically (HfSe2), zirconium sulfide (typically ZrS2), zirconium selenide (alternative) Examples include ZrSe2).

[0222] <Method for fabricating semiconductor devices> Next, Figure 6 shows a method for manufacturing a semiconductor device, which is one embodiment of the present invention, as shown in Figures 3A to 3D. This will be explained using Figures A through 21D.

[0223] In Figures 6A to 21D, A in each figure indicates a top view. Also, B in each figure indicates A in each figure. This is a cross-sectional view corresponding to the area indicated by the dashed line A1-A2 shown, and is of transistor 200. This is also a cross-sectional view in the direction of the channel length. Furthermore, C in each figure corresponds to the dashed line A3-A4 in A of each figure. This is a cross-sectional view corresponding to the part indicated, and is also a cross-sectional view of transistor 200 in the channel width direction. Yes. Also, in each figure, D is a cross-sectional view of the area indicated by the dashed line A5-A6 in A of each figure. This is also a cross-sectional view of the opening area 400. Note that in the top view A of each figure, for clarity of the figure, The "part" element has been omitted.

[0224] In the following, insulating materials for forming an insulator and conductive materials for forming a conductor are used. Materials, or oxide materials for forming oxides, are produced by sputtering, CVD, MBE, etc. The film can be deposited using appropriate methods such as the PLD method and ALD method.

[0225] Furthermore, the sputtering method uses a high-frequency power supply for sputtering, which is called RF sputtering. Ring method, DC sputtering method using a DC power supply, and pulsed application of electricity to the electrodes There is a pulsed DC sputtering method that changes the pressure. RF sputtering is mainly used for insulating films. It is used when depositing thin films, and DC sputtering is mainly used when depositing metallic conductive films. It can be used. Also, pulsed DC sputtering is mainly used for oxides, nitrides, carbides, etc. It is used when depositing compounds into films using the reactive sputtering method.

[0226] Furthermore, the CVD method is a type of plasma CVD (PECVD) that utilizes plasma. Enhanced CVD (Enhanced CVD), Thermal CVD (TCVD: Thermal CCVD) which utilizes heat. It can be classified into methods such as the VD method and the photoCVD method which utilizes light. Depending on the source gas used, the process can be metal CVD (MCVD) or organometallic CVD. It can be divided into (MOCVD: Metal Organic CVD) methods.

[0227] Plasma CVD can produce high-quality films at relatively low temperatures. Thermal CVD, on the other hand, is a method that can produce high-quality films at low temperatures. A film deposition method that does not use Zuma, thus minimizing plasma damage to the workpiece. For example, wiring, electrodes, and elements (transistors, capacitive elements, etc.) included in semiconductor devices. ) and others can be charged up by receiving an electric charge from the plasma. In cases where the accumulated charge destroys the wiring, electrodes, and elements contained in the semiconductor device. On the other hand, in the case of thermal CVD methods that do not use plasma, such plasma damage occurs. Therefore, the yield of semiconductor devices can be increased. Also, in the thermal CVD method, Because plasma damage does not occur within the film, a film with fewer defects can be obtained.

[0228] Furthermore, in the ALD method, the reaction between the precursor and reactant is carried out using only thermal energy. Thermal ALD (Thermal Altode Discharge) method, using plasma-excited reactants. Methods such as EALD (Plasma Enhanced Alopecia) can be used.

[0229] Furthermore, the ALD method utilizes the self-regulating properties of atoms to deposit atoms layer by layer. This allows for the deposition of extremely thin films, enabling film deposition on structures with high aspect ratios, and pinholes. It enables film formation with fewer defects such as blemishes, enables film formation with excellent coverage, and enables film formation at low temperatures. What are the effects? In the PEALD method, by using plasma, film deposition at lower temperatures is possible. This can be beneficial in some cases. Furthermore, the precursor used in the ALD method contains impurities such as carbon. Some contain [this]. Therefore, films formed by the ALD method are different from films formed by other film formation methods. Compared to a standard film, it may contain more impurities such as carbon. Note that the quantitative determination of impurities is done using X. X-ray Photoelectron Spectros (XPS) This can be done using `copy`.

[0230] CVD and ALD are film deposition methods in which particles emitted from a target or other source are deposited. Unlike other methods, this is a film-forming method in which a film is formed by a reaction on the surface of the object being treated. This film-forming method is less affected by the shape of the workpiece and has good step-level coverage. Furthermore, the ALD method has excellent step coverage and excellent thickness uniformity, thus aspect ratio This method is suitable for coating the surface of high-aperture openings, etc. However, the ALD method is relatively suitable for film formation. Because of its slow rate, it should be used in combination with other film deposition methods that have a faster deposition rate, such as CVD. In some cases, this may be preferable.

[0231] The CVD and ALD methods control the composition of the resulting film by adjusting the flow rate ratio of the source gases. This is possible. For example, in the CVD method and ALD method, the flow rate ratio of the raw material gas can be adjusted as needed. A film with the following composition can be formed. Furthermore, for example, in the CVD method and ALD method, film formation can be performed. By changing the flow rate ratio of the raw material gas while simultaneously depositing a film with a continuously changing composition. This is possible. When forming a film while changing the flow rate ratio of the raw material gas, multiple deposition chambers can be used. Compared to the method of film deposition using a conveyor belt, it eliminates the time required for transport and pressure adjustment, thus reducing the time required for film deposition. The interval can be shortened. Therefore, the productivity of semiconductor devices can be increased. There is.

[0232] First, a substrate (not shown) is prepared, and an insulator 212 is deposited on the substrate (Figure 6A). (See Figure 6D.) The insulator 212 is preferably deposited using the sputtering method. It is possible to use a sputtering method that does not require the use of hydrogen as the film-forming gas, insulator 21 The hydrogen concentration in 2 can be reduced. However, the deposition of the insulator 212 is done by sputtering. This method is not limited to the GRAV method; CVD, MBE, PLD, ALD, etc., may be used as appropriate. That's fine.

[0233] In this embodiment, the insulator 212 is used as the silicon target in an atmosphere containing nitrogen gas. Using this method, silicon nitride is deposited by pulsed DC sputtering. By using the ring method, particle generation due to arcing on the target surface is suppressed. This allows for a more uniform film thickness distribution. Furthermore, by using a pulsed voltage... By doing so, the rise and fall times of the discharge can be made steeper than with high-frequency voltage. This allows for more efficient power supply to the electrodes, improving the sputtering rate and film quality. It is possible.

[0234] By using an insulator that is resistant to the permeability of impurities such as water and hydrogen, such as silicon nitride, This can suppress the diffusion of impurities such as water and hydrogen contained in the layer below the insulator 212. Furthermore, as the insulator 212, an insulator that is impermeable to copper, such as silicon nitride, may be used. Therefore, a diffusive metal such as copper is used in the conductor layer below the insulator 212 (not shown). Even if present, it is possible to suppress the upward diffusion of the metal through the insulator 212.

[0235] Next, an insulator 214 is deposited on the insulator 212 (see Figures 6A to 6D). Insulator The deposition of film 214 is preferably carried out using the sputtering method. Hydrogen is used as the deposition gas. By using the sputtering method, which is not strictly necessary, the hydrogen concentration in the insulator 214 can be reduced. This is possible. However, the deposition of the insulator 214 is not limited to the sputtering method. CVD, MBE, PLD, ALD, etc. may be used as appropriate.

[0236] In this embodiment, the insulator 214 is an aluminum target in an atmosphere containing oxygen gas. Using a tweezers, aluminum oxide is deposited using the pulsed DC sputtering method. By using the sputtering method, the film thickness distribution can be made more uniform, and the sputtering rate and film The quality can be improved. Here, RF (Radio Frequency) power is applied to the substrate. A force may be applied. Depending on the magnitude of the RF power applied to the substrate, the layer below the insulator 214 may be affected. The amount of oxygen injected can be controlled. The RF power is 0 W / cm². 2 Larger , 1.86 W / cm² 2 The following applies: In other words, the RF power during the formation of the insulator 214 Therefore, the amount of oxygen injected can be varied to suit the characteristics of the transistor. It is possible to inject an amount of oxygen suitable for improving the reliability of the inverter. Also, the RF frequency is... A frequency of 10 MHz or higher is preferable. A typical example is 13.56 MHz. (High RF frequency) This reduces the damage inflicted on the circuit board.

[0237] As an insulator 214, it has an amorphous structure with high functionality for capturing and fixing hydrogen. It is preferable to use a metal oxide having such properties, for example, aluminum oxide. This provides an insulating Hydrogen contained in the surrounding material 216, etc., is captured or fixed, and the hydrogen diffuses into the oxide 230. This can prevent this. In particular, as the insulator 214, aluminum oxide having an amorphous structure is used. By using aluminum or amorphous aluminum oxide, water can be filtered more effectively. It is preferable because it can capture or fix the element. This gives it good properties and reliability. Highly reliable transistors 200 and semiconductor devices can be fabricated.

[0238] Next, an insulator 216 is deposited on the insulator 214 (see Figures 6A to 6D). Insulator The deposition of film 216 is preferably carried out using the sputtering method. Hydrogen is used as the deposition gas. By using the sputtering method, which is not strictly necessary, the hydrogen concentration in the insulator 216 can be reduced. This is possible. However, the deposition of the insulator 216 is not limited to the sputtering method. CVD, MBE, PLD, ALD, etc. may be used as appropriate.

[0239] In this embodiment, the insulator 216 is used as the silicon target in an atmosphere containing oxygen gas. Using this method, silicon oxide is deposited by pulsed DC sputtering. By using the ring method, the film thickness distribution can be made more uniform, improving the sputtering rate and film quality. It is possible.

[0240] Insulators 212, 214, and 216 are continuously used without exposure to the atmosphere. It is preferable to deposit the film in this manner. For example, a multi-chamber type film deposition apparatus may be used. This reduces the amount of hydrogen in the film of insulators 212, 214, and 216. This process allows for the formation of a film, and furthermore, reduces the incorporation of hydrogen into the film between each film formation step. .

[0241] Next, an opening is formed in the insulator 216 that reaches the insulator 214 (see Figures 6A to 6D). An opening includes, for example, grooves and slits. It also refers to the area in which an opening is formed. In some cases, this may create an opening. The opening may be formed using wet etching, but dry Using etching is preferable for microfabrication. Also, the insulator 214 is the same as the insulator 21 Select an insulator that functions as an etching stopper film when etching 6 to form grooves. It is preferable to do so. For example, silicon oxide or nitrided silicon oxide may be used for the insulator 216 that forms the groove. When silicon is used, the insulator 214 is silicon nitride, aluminum oxide, hafni oxide It's best to use "um".

[0242] As a dry etching apparatus, a capacitively coupled plasma (CCP) system with parallel plate electrodes is used. (Capacitively Coupled Plasma) Etching apparatus is used. Capacitively coupled plasma etching apparatus having parallel plate electrodes can be used. Alternatively, a high-frequency voltage may be applied to one electrode of the type electrode. Or, one of the parallel plate type electrodes. Alternatively, a configuration in which multiple different high-frequency voltages are applied to the electrodes may be used. Or a parallel plate type electrode Alternatively, a configuration in which the same high-frequency voltage is applied to each of them is also possible. Alternatively, a configuration in which high-frequency voltages of different frequencies are applied may be used. Or, a high-density plasma source may be used. A dry etching apparatus can be used. Dry etching with a high-density plasma source. The device is, for example, an inductively coupled plasma (ICP) device. Etching equipment such as an ed Plasma etching device can be used.

[0243] After the opening is formed, a conductive film 205A is deposited (see Figures 6A to 6D). Conductive film 20 5A preferably contains a conductor that has the function of suppressing oxygen permeation. For example, nitride Tantalum, tungsten nitride, titanium nitride, etc. can be used. Alternatively, oxygen permeability A conductor having a function to suppress overheating, and tantalum, tungsten, titanium, molybdenum, and It can be a multilayer film of aluminum, copper, and molybdenum tungsten alloy. Conductive film 2 The 05A film is deposited using sputtering, CVD, MBE, PLD, ALD, etc. It can be done by doing so.

[0244] In this embodiment, titanium nitride is deposited as the conductive film 205A. By using a material in the lower layer of the conductor 205b, the conductor 20 is made possible by the insulator 216, etc. This can suppress the oxidation of 5b. Furthermore, the diffusion of copper and other materials as the conductor 205b can be suppressed. Even when using a metal that is prone to diffusing, it is possible to prevent the metal from diffusing out of the conductor 205a. Cut.

[0245] Next, the conductive film 205B is deposited (see Figures 6A to 6D). These are tantalum, tungsten, titanium, molybdenum, aluminum, copper, and molybdenum tan. Gusten alloys and the like can be used. The conductive film can be formed by plating, sputtering, etc. This can be carried out using methods such as CVD, MBE, PLD, and ALD. In terms of form, tungsten is deposited as the conductive film 205B.

[0246] Next, a CMP treatment is performed to remove a portion of conductive film 205A and conductive film 205B. , the insulator 216 is exposed (see Figures 7A to 7D). As a result, conductive material is present only at the opening. Body 205a and conductor 205b remain. Note that the insulator 21 Part of 6 may be removed.

[0247] Next, etching is performed to remove the upper part of the conductor 205b (see Figures 8A to 8D). . ) As a result, the upper surface of the conductor 205b is connected to the upper surface of the conductor 205a and the insulator 216 It will be lower than the top surface. For etching the conductor 205b, dry etching or wet etching is used. While etching can be used, dry etching is preferable for microfabrication. .

[0248] Next, a conductive film 205C is applied to the insulator 216, the conductor 205a, and the conductor 205b. A film is formed (see Figures 9A to 9D). Conductive film 205C is formed in the same way as conductive film 205A. It is desirable to include a conductor that has the function of suppressing oxygen permeation.

[0249] In this embodiment, titanium nitride is deposited as the conductive film 205C. By using the material on top of the conductor 205b, the conductor 20 is made possible by the insulator 222, etc. This can suppress the oxidation of 5b. Furthermore, the diffusion of copper and other materials as the conductor 205b can be suppressed. Even when using a metal that is prone to diffusing, it is possible to prevent the metal from diffusing out of the conductor 205c. Cut.

[0250] Next, CMP treatment is performed to remove a portion of the conductive film 205C and expose the insulator 216. (See Figures 10A to 10D.) As a result, the conductive material 205a is present only in the opening. Body 205b and conductor 205c remain. As a result, the top surface of the conductor 20 5 can be formed. Furthermore, the conductor 205b can form conductor 205a and conductor 2 The structure is enclosed in 05c. Therefore, impurities such as hydrogen are not conductive from the conductive material 205b. To prevent diffusion outside of body 205a and conductor 205c, and to prevent diffusion outside of conductor 205a and conductor This prevents oxygen from entering from outside the conductive material 205c and oxidizing the conductive material 205b. Note that this CMP treatment may remove a portion of the insulator 216.

[0251] Next, an insulator 222 is formed on the insulator 216 and the conductor 205 (Figures 11A to 11A). See Figure 11D.) As insulator 222, one or both aluminum and hafnium. It is preferable to form an insulator containing one of the oxides. Note that one of aluminum and hafnium Alternatively, as an insulator containing both oxides, aluminum oxide, hafnium oxide, aluminum It is preferable to use oxides containing um and hafnium (such as hafnium aluminate). Insulators containing oxides of aluminum and / or hafnium are suitable for oxygen, It has barrier properties against hydrogen and water. The insulator 222 has barrier properties against hydrogen and water. By having properties, hydrogen contained in the structure provided around transistor 200, The diffusion of priming fluid into the inside of the transistor 200 through the insulator 222 is suppressed. This can suppress the formation of oxygen vacancies in oxide 230.

[0252] The insulator 222 was deposited using sputtering, CVD, MBE, PLD, and ALD methods. This can be done using methods such as the above. In this embodiment, the ALD method is used for the insulator 222. Then, a hafnium oxide film is deposited.

[0253] Next, it is preferable to perform a heat treatment. The heat treatment is preferably performed at a temperature of 250°C to 650°C. It is preferable to carry it out at a temperature of 300°C to 500°C, and more preferably at 320°C to 450°C. The heat treatment is performed in an atmosphere of nitrogen gas or an inert gas, or with an oxidizing gas for 10 minutes. The procedure should be carried out in an atmosphere containing ppm or more, 1% or more, or 10% or more. For example, nitrogen gas and oxygen. When performing heat treatment in a gas mixture atmosphere, it is sufficient to use about 20% oxygen gas. The heat treatment may be carried out under reduced pressure. Alternatively, the heat treatment may be carried out under nitrogen gas or an inert gas. After heat treatment in an atmosphere, an oxidizing gas of 10 ppm or more is added to replenish the desorbed oxygen. Heat treatment may be carried out in an atmosphere containing % or more, or 10% or more.

[0254] Furthermore, it is preferable that the gas used in the above heat treatment is highly purified. For example, The amount of moisture contained in the gas used in the heat treatment described above is 1 ppb or less, preferably 0.1 ppb or less. More preferably, the level should be 0.05 ppb or less. Heat treatment using highly purified gas. By performing this process, it is possible to prevent moisture and other substances from being absorbed into the insulator 222, etc., as much as possible. can.

[0255] In this embodiment, as a heat treatment, after the film formation of the insulator 222, nitrogen gas and oxygen gas are used. The process is carried out at a temperature of 400°C for 1 hour with a flow rate ratio of 4:1. This heat treatment will result in It is possible to remove impurities such as water and hydrogen contained in the insulator 222. When an oxide containing hafnium is used as body 222, the heat treatment results in an insulator In some cases, a portion of 222 may crystallize. Also, heat treatment is performed after the deposition of the insulator 224. It can also be done at the right time.

[0256] Next, an insulating film 224 is deposited on the insulating film 222 (see Figures 11A to 11D). The edge material 224 is deposited using sputtering, CVD, MBE, PLD, ALD, etc. This can be done using the sputtering method. In this embodiment, the insulator 224 is made of sputtering material. A silicon oxide film is deposited using this method. Sputtering does not require the use of hydrogen as the deposition gas. By using this method, the hydrogen concentration in the insulator 224 can be reduced. The insulator 224 is Since it comes into contact with oxide 230a in a later process, the hydrogen concentration is reduced in this way. It is suitable.

[0257] Next, oxide film 230A and oxide film 230B are deposited sequentially on the insulator 224 (Figure 11A). (See Figure 11D.) Note that oxide films 230A and 230B are exposed to the atmospheric environment. It is preferable to deposit the film continuously without opening it to the atmosphere. By depositing the film without opening it to the atmosphere, the oxide film 230 A, and to prevent impurities or moisture from the atmospheric environment from adhering to the oxide film 230B. This allows the vicinity of the interface between oxide film 230A and oxide film 230B to be kept clean.

[0258] The oxide films 230A and 230B were deposited by sputtering, CVD, and MBE. This can be done using methods such as the PLD method and the ALD method.

[0259] For example, oxide film 230A and oxide film 230B are deposited by sputtering. In this case, oxygen or a mixture of oxygen and a noble gas is used as the sputtering gas. By increasing the proportion of oxygen in the puttering gas, excess oxygen in the formed oxide film... This can increase the amount. Also, when the above oxide film is deposited by sputtering: The above-mentioned In-M-Zn oxide targets can be used.

[0260] In particular, during the deposition of oxide film 230A, some of the oxygen contained in the sputtering gas acts as an insulator. It may be supplied to 224. Therefore, the oxygen contained in the sputtering gas The percentage should be 70% or more, preferably 80% or more, and more preferably 100%.

[0261] Furthermore, when forming oxide film 230B by sputtering, the sputtering gas contains The proportion of oxygen is greater than 30% and less than or equal to 100%, preferably between 70% and 100%. When a film is formed using this method, an oxygen-rich oxide semiconductor is created. The transistors used in the channel formation region offer relatively high reliability. However, this generation One aspect of the invention is not limited to this. When the oxide film 230B is formed by sputtering, The proportion of oxygen in the sputtering gas should be 1% or more and 30% or less, preferably 5% or more. When the film is deposited with an oxygen content of 0% or less, an oxygen-deficient oxide semiconductor is formed. Transistors using a monocrystalline semiconductor in the channel formation region can achieve relatively high field-effect mobility. Furthermore, by performing film deposition while heating the substrate, the crystallinity of the oxide film can be improved. It can be done.

[0262] In this embodiment, the oxide film 230A is formed by sputtering, using the In:Ga: The film is deposited using an oxide target with a Zn = 1:3:4 [atomic ratio]. Also, oxide film 23 As 0B, by sputtering, In:Ga:Zn=4:2:4.1 [atomic ratio] The film is deposited using the oxide target of ]. Note that each oxide film is formed under different deposition conditions and atomic ratios. By selecting appropriately, the desired properties for oxide 230a and oxide 230b can be determined. It is good to form it.

[0263] Next, an oxide film 243A is deposited on the oxide film 230B (see Figures 11A to 11D). The 243A oxide film was deposited using sputtering, CVD, MBE, PLD, and ALD methods. This can be done using methods such as the following. The oxide film 243A has an atomic ratio of Ga to In, which is acid It is preferable that the atomic ratio of Ga to In in the film 230B is greater than that of In. This is an oxide film 243A, produced by sputtering, with an In:Ga:Zn ratio of 1:3:4. The film is deposited using an oxide target with an atomic ratio of [number of atoms].

[0264] Note that the insulator 222, insulator 224, oxide film 230A, oxide film 230B, and oxide film It is preferable to deposit 243A by sputtering without exposing it to the atmosphere. For example, a multi-chamber type film deposition apparatus can be used. This allows for the deposition of insulator 222, The edge body 224, oxide film 230A, oxide film 230B, and oxide film 243A, the hydrogen in the film It reduces the amount of hydrogen present during film formation, and further reduces the amount of hydrogen mixed into the film between each film formation step. can.

[0265] Next, it is preferable to perform a heat treatment. The heat treatment is performed on oxide film 230A and oxide film 230B. The process should be carried out within a temperature range in which the oxide film 243A does not undergo polycrystallization, which is between 250°C and 650°C. The following steps should preferably be performed at a temperature of 400°C to 600°C. Note that the heat treatment is performed using nitrogen gas. Alternatively, an inert gas atmosphere, or an oxidizing gas at 10 ppm or more, 1% or more, The process should be carried out in an atmosphere containing 10% or more of the substance. For example, heat treatment should be performed in a mixed atmosphere of nitrogen and oxygen gas. In this case, the oxygen gas concentration should be around 20%. Also, the heat treatment can be performed under reduced pressure. Alternatively, the heat treatment may involve heating in a nitrogen or inert gas atmosphere followed by desorption. An atmosphere containing oxidizing gas at a concentration of 10 ppm or more, 1% or more, or 10% or more to replenish the oxygen. Heat treatment may be performed in an open atmosphere.

[0266] Furthermore, it is preferable that the gas used in the above heat treatment is highly purified. For example, The amount of moisture contained in the gas used in the heat treatment described above is 1 ppb or less, preferably 0.1 ppb or less. More preferably, the level should be 0.05 ppb or less. Heat treatment using highly purified gas. By performing this process, moisture, etc., is removed from oxide film 230A, oxide film 230B, and oxide film 243A. This can prevent it from being absorbed as much as possible.

[0267] In this embodiment, the heat treatment is performed at a temperature of 400°C for 1 hour in a nitrogen atmosphere. After this, the process is carried out continuously in an oxygen atmosphere at a temperature of 400°C for 1 hour. According to the principle, water, hydrogen, etc. in oxide film 230A, oxide film 230B, and oxide film 243A This allows for the removal of impurities, etc. Furthermore, this heat treatment results in the oxide film 230B This improves the crystallinity and creates a denser, more compact structure. The diffusion of oxygen or impurities within the film 230B can be reduced.

[0268] Next, a conductive film 242A is deposited on the oxide film 243A (see Figures 11A to 11D). The conductive film 242A was deposited using sputtering, CVD, MBE, PLD, and ALD methods. This can be done using methods such as the following. For example, the conductive film 242A can be produced using the sputtering method. Then, a tantalum nitride film should be formed. Note that a heat treatment should be performed before forming the conductive film 242A. This may be done under reduced pressure, without exposure to air, and continuously to form a conductive film 2 42A may be formed as a film. By performing such a treatment, the surface of the oxide film 243A It removes moisture and hydrogen adsorbed on it, and further, oxide film 230A, oxide film 230B, Furthermore, the water concentration and hydrogen concentration in the oxide film 243A can be reduced. The temperature is preferably between 100°C and 400°C. In this embodiment, the heat treatment temperature is set to 2 Let's set the temperature to 0°C.

[0269] Next, an insulating film 271A is deposited on the conductive film 242A (see Figures 11A to 11D). The insulating film 271A is deposited by sputtering, CVD, MBE, PLD, or A This can be done using methods such as the LD method. The insulating film 271A has a function to suppress oxygen permeation. It is preferable to use an insulating film having sputtering. For example, as insulating film 271A, sputtering Depending on the method, aluminum oxide or silicon nitride can be deposited as a thin film.

[0270] In this embodiment, as the insulating film 271A, an aluminium is used in an atmosphere containing oxygen gas. Using a GET, aluminum oxide is deposited by pulsed DC sputtering. The RF power applied to the board is 0.62 W / cm². 2 The following applies: Preferably, 0 W / cm²2 That's all. 0.31 W / cm² 2 The following applies: By reducing the RF power, the amount injected into the conductive film 242A is reduced. This suppresses the amount of oxygen released and prevents oxidation of the conductive film 242A.

[0271] Furthermore, the conductive film 242A and the insulating film 271A are not exposed to the atmosphere, and sputtering is performed. It is preferable to deposit the film using the densification method. For example, if a multi-chamber type film deposition apparatus is used... Good. This reduces the amount of hydrogen in the conductive film 242A and the insulating film 271A during film formation. Furthermore, it is possible to reduce the incorporation of hydrogen into the film between each film formation process. When a hard mask is provided on the insulating film 271A, the film that will become the hard mask will also be exposed to the atmosphere. The film should be deposited continuously without exposure.

[0272] Next, using lithography, oxide film 230A, oxide film 230B, and oxide film 243A were obtained. The conductive film 242A and insulating film 271A are processed into island shapes, and oxide 230a and oxide 2 Forming 30b, an oxide layer 243B, a conductive layer 242B, and an insulating layer 271B (Figure 12) See A to Figure 12D. Furthermore, this process can be performed using dry etching or wet etching methods. It can be used. Dry etching is suitable for microfabrication. Also, Oxide film 230A, oxide film 230B, oxide film 243A, conductive film 242A, and insulating layer 27 The processing of 1B may be carried out under different conditions. Also, in this process, the insulator 224 is superimposed with oxide 230a and processed into an island-like structure.

[0273] In lithography, the resist is first exposed through a mask. Next, exposure... The selected area is removed or left intact using a developer to form a resist mask. Next, By etching through the resist mask, conductors, semiconductors, or insulators can be etched. These can be processed into desired shapes. For example, KrF excimer laser light, ArF excimer laser light Using sima laser light, EUV (Extreme Ultraviolet) light, etc., A resist mask can be formed by exposing the dyst. Also, the relationship between the substrate and the projection lens An immersion technique may be used, in which a liquid (e.g., water) is filled in between and then exposed. Alternatively, the aforementioned light Alternatively, electron beams or ion beams may be used. When using this method, a mask is not required. Note that a resist mask is used in processes such as ashing. After performing dry etching, wet etching, and dry etching Perform wet etching, or dry etching after wet etching. It can be removed by performing the necessary procedures.

[0274] Furthermore, a hard mask made of an insulator or conductor may be used beneath the resist mask. When using a hard mask, an insulating film or conductive film that will serve as the hard mask material will be placed on the conductive film 242A. By forming a hard mask, then forming a resist mask on top of it, and etching the hard mask material... A hard mask of the desired shape can be formed. Etching of conductive film 242A, etc. You can either remove the resist mask before proceeding, or you can proceed with the resist mask still in place. Good. In the latter case, the resist mask may disappear during etching. Conductive film 242 After etching A, the hard mask may be removed by etching. If the mask material does not affect subsequent processes, or can be used in subsequent processes, then it is not necessarily hard. There is no need to remove the mask. In this embodiment, the insulating layer 271B is used as a hard mask. It is used. When the insulating layer 271B is a hard mask, the film thickness of the insulating layer 271B is adjusted as appropriate. It is preferable to arrange the film in a way that suppresses the disappearance of the insulating layer 271B during etching of the conductive film 242A, etc. It's nice.

[0275] Here, the insulating layer 271B functions as a mask for the conductive layer 242B, as shown in Figure 12B. As shown in Figure 12C, the conductive layer 242B does not have a curved surface between its side and top surfaces. As a result, the conductors 242a and 242b shown in Figure 3B have ends where the side surface and the top surface intersect. The end where the side and top surfaces of the conductor 242 meet becomes angular, and the end becomes Compared to the case where it has a curved surface, the cross-sectional area of ​​the conductor 242 becomes larger. As a result, the conductor 2 Since the resistance of 42 is reduced, the on-current of transistor 200 can be increased. .

[0276] Also, insulator 224, oxide 230a, oxide 230b, oxide layer 243B, conductive layer 2 42B and the insulating layer 271B are formed such that at least a portion of them overlap with the conductor 205. Also, insulator 224, oxide 230a, oxide 230b, oxide layer 243B, conductive layer The sides of 242B and the insulating layer 271B are substantially perpendicular to the top surface of the insulator 222. Preferably, an insulator 224, oxide 230a, oxide 230b, oxide layer 243B, The sides of the conductive layer 242B and the insulating layer 271B are approximately perpendicular to the upper surface of the insulator 222. This makes it possible to reduce the area and increase the density when providing multiple transistors 200. Alternatively, insulator 224, oxide 230a, oxide 230b, oxide layer 243B, conductive The angle between the side surfaces of layer 242B and insulating layer 271B and the top surface of insulator 222 is 90 degrees. A configuration with a lower angle is also possible. In that case, the insulator 224, oxide 230a, oxide Sides of 230b, oxide layer 243B, conductive layer 242B, and insulating layer 271B, and the insulator The angle between the top surface of 222 and the surface is preferably 60 degrees or more and less than 70 degrees. In subsequent processes, the coating properties of the insulator 272 and other materials are improved, reducing defects such as porosity. It is possible.

[0277] Furthermore, the by-products generated in the etching process are insulator 224, oxide 230a, and acid Layers are present on the sides of the oxide layer 230b, oxide layer 243B, conductive layer 242B, and insulating layer 271B. In some cases, the layered by-product may be formed as insulator 224, oxide 23 0a, oxide 230b, oxide 243, conductor 242, and insulator 271 and insulator 27 This will be formed between steps 2. With the layered by-product formed, the process will proceed. When transistor 200 is fabricated, its reliability may deteriorate. Therefore, it is preferable to remove the layered by-product.

[0278] Next, insulator 222, insulator 224, oxide 230a, oxide 230b, oxide layer 24 An insulator 272 is formed on 3B, the conductive layer 242B, and the insulating layer 271B (Figure 13). (See A to Figure 13D.) The insulator 272 was deposited by sputtering, CVD, and MBE. This can be done using methods such as the PLD method and the ALD method. In this embodiment, the insulator 27 2. Using an aluminum target in an atmosphere containing oxygen gas, pulse DC spall Aluminum oxide is deposited using the Tarling method. The RF power applied to the substrate is 0.62W. / cm 2 The following applies: Preferably, 0 W / cm² 2 More than 0.31W / cm 2 The following applies: R By reducing the F power, the amount of oxygen injected into the insulator 224 can be suppressed. Furthermore, the insulator 272 is in close contact with a portion of the upper surface of the insulator 222.

[0279] Furthermore, the insulator 272 may have a laminated structure. For example, by sputtering, Aluminum oxide is deposited as a film, and then nitride is applied to the aluminum oxide by sputtering. A film of ricon may be formed. By making the insulator 272 such a multilayer structure, water, hydrogen, This may improve the ability to suppress the diffusion of certain impurities and oxygen.

[0280] In this way, oxide 230a, oxide 230b, oxide layer 243B, and conductive layer 242B is an insulator 272 and an insulating layer 271B, which have the function of suppressing oxygen diffusion. It can be covered with this. This allows for subsequent processes to remove oxide 230a, oxide 230b, and acid This reduces the diffusion of oxygen into the ionized layer 243B and the conductive layer 242B.

[0281] Next, an insulating film that will become an insulator 280 is formed on the insulator 272. This can be done using methods such as sputtering, CVD, MBE, PLD, and ALD. Yes, it is possible. For example, a silicon oxide film can be formed as the insulating film using the sputtering method. The insulating film, which will become the insulator 280, is deposited by sputtering in an oxygen-containing atmosphere. By doing so, an insulator 280 containing excess oxygen can be formed. Also, water is used as the film-forming gas. By using a sputtering method that does not require the use of a particle, the hydrogen concentration in the insulator 280 can be reduced. It can be reduced. Furthermore, a heat treatment may be performed before the deposition of the insulating film. Heat treatment This process may be carried out under reduced pressure, and the insulating film may be deposited continuously without exposure to the atmosphere. By performing such a process, moisture and water adsorbed on the surface of the insulator 272 can be removed. The element is removed, and further oxide 230a, oxide 230b, oxide layer 243B, and insulator The water and hydrogen concentrations in 224 can be reduced. The heat treatment described above The following heat treatment conditions can be used.

[0282] Next, the insulating film that will become the insulator 280 is subjected to CMP treatment, and the insulator 280 has a flat top surface. Forms (see Figures 13A to 13D). Furthermore, on the insulator 280, for example, spats A silicon nitride film is formed by the taring method, and the silicon nitride is deposited until it reaches the insulator 280. CMP processing may also be performed.

[0283] Next, a portion of the insulator 280, a portion of the insulator 272, a portion of the insulating layer 271B, and the conductive layer 24 Part of 2B and part of the oxide layer 243B are processed to create an opening that reaches the oxide 230b. The opening is formed. It is preferable that the opening be formed so as to overlap with the conductor 205. Through the formation of insulator 271a, insulator 271b, conductor 242a, conductor 242b, Oxide 243a and oxide 243b are formed (see Figures 14A to 14D).

[0284] When forming the above-mentioned opening, the upper part of oxide 230b may be removed. By removing a portion of 0b, grooves are formed in the oxide 230b. Therefore, the groove may be formed in the above-mentioned opening formation step, or the opening formation step and They may be formed using different processes.

[0285] Also, a portion of the insulator 280, a portion of the insulator 272, a portion of the insulating layer 271B, and the conductive layer 24 Processing of part of 2B and part of the oxide layer 243B is done by dry etching or weld Dry etching can be used. Dry etching is suitable for microfabrication. Furthermore, the processing may be carried out under different conditions. For example, insulator 2 A portion of 80 was processed by dry etching, and a portion of the insulator 272 and the insulating layer 271B were processed. A portion of the conductive layer 242B and the oxide layer 243 are processed by a wet etching method. A portion of B may be processed by dry etching. Also, a portion of the conductive layer 242B and oxidation The processing of part of material layer 243B may be carried out under different conditions.

[0286] Here, the side surface of oxide 230a, the top and side surfaces of oxide 230b, and the side of conductor 242. Impurities may adhere to surfaces, such as the sides of the insulator 280, or diffuse into the interior of these surfaces. This may occur. A process to remove such impurities may be performed. Also, the above dryer Damage areas may be formed on the oxide 230b surface during chipping. The impurities may be removed. These impurities include insulator 280, insulator 272, and insulating layer 271B. A portion of the components contained in the conductive layer 242B, and the apparatus used to form the above-mentioned opening. Components contained in the materials used, and components contained in the gas or liquid used for etching. Examples of impurities include those caused by certain components. Examples of such impurities include hafnium and aluminum. Examples include nium, silicon, tantalum, fluorine, and chlorine.

[0287] In particular, impurities such as aluminum or silicon are CAAC-O230b oxide. It inhibits S formation. Therefore, it inhibits CAAC-OS formation of aluminum or silicon. It is preferable that harmful impurity elements are reduced or removed. For example, oxide 230 b, and its vicinity, should have a concentration of aluminum atoms of 5.0 atomic percent or less. Preferably, 2.0 atomic% or less, more preferably 1.5 atomic% or less, and 1.0 atomic% or less. More preferably, and even more preferably less than 0.3 atomic percent.

[0288] Furthermore, impurities such as aluminum or silicon can inhibit the formation of CAAC-OS. , pseudo-amorphous oxide semiconductor (a-like OS: amorphous-like ox The region of the metal oxide that has become an ide semiconductor is considered a non-CAAC region. It may be called that. In the non-CAAC region, the density of the crystal structure is reduced, so V O H It forms in large quantities, making it easier for transistors to become normally-on. Therefore, oxide 230 It is preferable that the non-CAAC region of b is reduced or eliminated.

[0289] In contrast, it is preferable that oxide 230b has a layered CAAC structure. It is preferable that the CAAC structure extends to the lower end of the drain of oxide 230b. In transistor 200, the conductor 242a or conductor 242b, and its vicinity. This functions as a drain. In other words, near the lower end of the conductor 242a (conductor 242b) Preferably, oxide 230b has a CAAC structure. In this way, drain pressure Even at the drain end, which significantly affects the CA, the damaged area of ​​oxide 230b is removed, Having an AC structure further suppresses fluctuations in the electrical characteristics of transistor 200. Yes, it is possible. Furthermore, it can improve the reliability of transistor 200.

[0290] To remove the above-mentioned impurities, a cleaning process is performed. The cleaning method involves using a cleaning solution, etc. These include wet cleaning using a squeegee, plasma treatment using plasma, and cleaning by heat treatment. The above cleaning methods may be combined as appropriate. Note that this cleaning process may deepen the grooves. This can happen.

[0291] For wet cleaning, use ammonia water, oxalic acid, phosphoric acid, hydrofluoric acid, etc., with carbonated water. Alternatively, the cleaning process may be carried out using an aqueous solution diluted with pure water, pure water, carbonated water, etc. Ultrasonic cleaning may be performed using these aqueous solutions, pure water, or carbonated water. Alternatively, These cleaning methods may be combined as appropriate.

[0292] In this specification, etc., an aqueous solution obtained by diluting commercially available hydrofluoric acid with pure water is referred to as diluted hydrofluoric acid. It is called an acid, and a solution obtained by diluting commercially available ammonia water with pure water is sometimes called diluted ammonia water. Yes. Furthermore, the concentration and temperature of the aqueous solution depend on the impurities to be removed and the semiconductor device being cleaned. The composition should be adjusted as appropriate. The ammonia concentration of the diluted ammonia solution should be 0.0 The concentration should be between 1% and 5%, preferably between 0.1% and 0.5%. The hydrogen fluoride concentration of the hydrochloric acid is 0.01 ppm to 100 ppm, preferably 0.1 ppm. It should be between 10 ppm and above.

[0293] For ultrasonic cleaning, a frequency of 200 kHz or higher, preferably 900 kHz or higher, is used. It is preferable to have this. By using this frequency, damage to oxides such as 230b is reduced. It can be reduced.

[0294] Furthermore, the above cleaning process may be performed multiple times, and the cleaning solution may be changed each time the cleaning process is performed. Example For example, the first cleaning treatment involves using diluted hydrofluoric acid or diluted ammonia water. In addition, a second washing treatment using pure water or carbonated water may be performed.

[0295] In this embodiment, as the above cleaning process, wet cleaning is performed using diluted hydrofluoric acid. Next, wet cleaning is performed using purified water or carbonated water. Removes impurities such as oxide 230a and oxide 230b that are attached to the surface or diffused into the interior. This can be done. Furthermore, the crystallinity of oxide 230b can be increased.

[0296] Heat treatment may be performed after the etching or cleaning described above. The heat treatment is 100 The heating process should be carried out at a temperature between 450°C and 450°C, preferably between 350°C and 400°C. The procedure involves an atmosphere of nitrogen gas or an inert gas, or an oxidizing gas at a concentration of 10 ppm or more, or 1%. The procedure should be carried out in an atmosphere containing the above amount, or 10% or more. For example, heat treatment should be performed in an oxygen atmosphere. This is preferable. This supplies oxygen to oxide 230a and oxide 230b, and oxygen V missing O This can reduce oxide 23. The crystallinity of 0b can be improved. Furthermore, the heat treatment may be performed under reduced pressure. Alternatively, the material may be heat-treated in an oxygen atmosphere, followed by continuous heat-treatment in a nitrogen atmosphere without exposure to the atmosphere. You may do so.

[0297] Next, an insulating film 250A, which will become the insulator 250a, is deposited (see Figures 15A to 15D). A heat treatment may be performed before the deposition of the insulating film 250A, and this heat treatment may be performed under reduced pressure. The insulating film 250A may be deposited continuously without exposure to air. This process is preferably carried out in an oxygen-containing atmosphere. By performing such a treatment, oxidation The moisture and hydrogen adsorbed on the surface of material 230b are removed, and further oxide 230a, Furthermore, the water and hydrogen concentrations in oxide 230b can be reduced. Heat treatment The temperature is preferably between 100°C and 400°C.

[0298] Insulating film 250A can be produced using methods such as sputtering, CVD, MBE, PLD, and ALD. It can be formed using [a specific method]. In addition, the insulating film 250A has reduced or removed hydrogen atoms. It is preferable to deposit the film using a film deposition method that utilizes a gas. This allows the water in the insulating film 250A to be deposited. The elemental concentration can be reduced. The insulating film 250A comes into contact with the oxide 230b in a later process. Since it becomes an insulator 250, it is preferable that the hydrogen concentration is reduced in this way.

[0299] Furthermore, it is preferable to deposit the insulating film 250A using the ALD method. The thickness of the insulator 250, which functions as a gate insulating film of the inverter 200, is extremely thin (e.g. For example, a range of 5nm to 30nm, and it is necessary to minimize the variation. In contrast, the ALD method alternately introduces a precursor and a reactant (oxidizing agent). This is a film deposition method, and the film thickness can be adjusted by repeating this cycle. Therefore, precise film thickness adjustment is possible. Thus, miniaturized transistor 200 is required. This enables the achievement of gate insulating film accuracy. Also, as shown in Figures 15B and 15C. As shown, the insulating film 250A is located on the bottom and side surfaces of the opening formed by the insulator 280, etc. Therefore, it is necessary to form a film with good coverage. On the bottom and side surfaces of the opening, the atomic layer is one Since it can be deposited layer by layer, the insulating film 250A can be applied to the opening with good coverage. It can be used to form a thin film.

[0300] Furthermore, for example, when depositing an insulating film 250A using the PECVD method, hydrogen-containing The membrane gas is decomposed in the plasma, generating a large amount of hydrogen radicals. Reduction of hydrogen radicals. The reaction removes oxygen from oxide 230b and V O When H is formed, oxide 2 The hydrogen concentration in 30b increases. However, the insulating film 250A is deposited using the ALD method. This suppresses the generation of hydrogen radicals both when introducing the precursor and when introducing the reactant. Therefore, by forming an insulating film 250A using the ALD method, the oxide can be formed. This prevents the hydrogen concentration in 230b from becoming too high.

[0301] If the above-mentioned impurities are not removed before the deposition of insulating film 250A, oxide 230a, acid The impurity remains between the ion 230b, conductor 242, insulator 280, etc. and the insulator 250a. It may exist.

[0302] Next, microwave treatment may be performed in an oxygen-containing atmosphere (see Figures 15A to 15D). ). Here, the dotted lines shown in Figures 15B to 15D represent microwaves, RF and other high-frequency waves, oxygen waves, etc. This refers to a rasma, or oxygen radical, etc. Microwave processing is, for example, using microwaves. It is preferable to use a microwave processing apparatus having a power source for generating high-density plasma. . Further, the microwave processing apparatus may have a power source for applying RF to the substrate side. High-density pla By using a zma, high-density oxygen radicals can be generated. Also, by applying RF to the substrate side, oxygen ions generated by high-density plasma can be efficiently introduced into the oxide 230b. Further, the above microwave processing is preferably performed under reduced pressure, and the pressure may be 60 Pa or more, preferably 133 Pa or more, more preferably 200 Pa or more, and further preferably 400 Pa or more and 700 Pa or less. Also, the acid When the oxygen flow ratio (O2 / O2+Ar) is 50% or less, preferably 10% or more and 30% or less, it is good. Also, the processing temperature may be 750 °C or less, preferably 500 °C or less, for example, about 400 °C. Further, after performing the oxygen plasma treatment, heat treatment may be continuously performed without exposing to the outside air.

[0303] As shown in FIGS. 15B to 15D, by performing microwave processing in an atmosphere containing oxygen, oxygen gas is plasmaized using microwaves or high-frequency waves such as RF, and the oxygen plasma ma is allowed to act on the region between the conductor 242a and the conductor 242b of the oxide 230b. At this time, it is also possible to irradiate the region 230bc with microwaves or high-frequency waves such as RF. That is, microwaves, high-frequency waves such as RF, oxygen plasma, etc. can be made to act on the region 230bc shown in FIG. 4. By the action of plasma, microwaves, etc., the V H in the region 230bc is segmented, and hydrogen H can be removed from the region 230bc. O That is, in the region 230bc, "V H→H+V O H → H + VO The reaction " occurred in area 230 The hydrogen concentration in bc can be reduced. Therefore, the oxygen deficiency in region 230bc, and V O This can reduce H and lower the carrier concentration. Furthermore, it forms in region 230bc. In the oxygen vacancies created, oxygen radicals generated by the oxygen plasma, or contained in the insulator 250, are added. By supplying oxygen, the oxygen deficiency in region 230bc is further reduced, and the carrier The concentration can be reduced.

[0304] On the other hand, in regions 230ba and 230bb shown in Figure 4, there are conductors 242a and A conductor 242b is provided. As shown in Figures 15B to 15D, the conductor 242a And conductor 242b is affected by microwaves, or high-frequency waves such as RF, oxygen plasma, etc. Because it is shielded, these effects do not extend to regions 230ba and 230bb. As a result, microwave processing is performed in regions 230ba and 230bb, V O H This prevents a decrease in carrier concentration because it does not result in a reduction or an oversupply of oxygen. Cut.

[0305] In this way, oxygen vacancies are selectively created in the oxide semiconductor region 230bc, and V O H By removing it, region 230bc can be made type i or substantially type i. Furthermore, Excessive flow in areas 230ba and 230bb, which function as drain areas or drain areas. This suppresses the supply of oxygen and maintains n-type formation. This suppresses fluctuations in the electrical characteristics of transistor 200, preventing variations in the electrical characteristics of transistor 200 within the substrate surface. It can suppress the growth.

[0306] Therefore, it is possible to provide a semiconductor device with less variation in transistor characteristics. Furthermore, it is possible to provide semiconductor devices with good reliability. In addition, it has good electrical characteristics. We can provide semiconductor devices.

[0307] Next, an insulating film 250B, which will become the insulator 250b, is deposited (see Figures 16A to 16D). The 250B insulating film is deposited using sputtering, CVD, MBE, PLD, and ALD. The film can be formed using methods such as [method name]. The insulating film 250B has a function that suppresses the diffusion of oxygen. It is preferable to form it using an insulator. With this configuration, the insulator 2 This can suppress the diffusion of oxygen contained in 50a into the conductor 260. In other words, This can suppress the decrease in the amount of oxygen supplied to the oxide 230. Also, the insulator 250a The oxidation of the conductor 260 by the contained oxygen can be suppressed. For example, insulating film 250 A is provided using a material that can be used for the insulator 250 described above, and the insulating film 250B is It can be provided using the same material as the insulator 222.

[0308] Specifically, the insulating film 250B is made of hafnium, aluminum, gallium, and yttrium. Umium, Zirconium, Tungsten, Titanium, Tantalum, Nickel, Germanium, Magnesium Metal oxides or oxides containing one or more metals selected from nesium, etc. Any metal oxide that can be used as 230 can be used. In particular, aluminum It is preferable to use an insulator containing an oxide of one or both of hafnium.

[0309] In this embodiment, silicon oxide nitride is used as the insulating film 250A by CVD, and insulation Hafnium oxide is deposited as film 250B using the thermal ALD method.

[0310] Microwave treatment may be performed after the deposition of the insulating film 250B. This microwave treatment is performed before The microwave treatment conditions described above, which are performed after the deposition of the insulating film 250A, may also be used. The microwave treatment performed after deposition of 50A is omitted, and the microwave treatment is performed after deposition of insulating film 250B. You may proceed with the processing.

[0311] Furthermore, after the deposition of insulating film 250A and after the deposition of insulating film 250B, the microwaves After processing, heat treatment may be performed while maintaining a reduced pressure state. In insulating film 250A, insulating film 250B, oxide 230b, and oxide 230a It can efficiently remove hydrogen. Also, some of the hydrogen is absorbed by conductor 242 (conductor 2 It may be gettered by 42a and conductor 242b), or by microwave. Even if the step of performing heat treatment while maintaining a reduced pressure state after processing is repeated multiple times Good. By repeatedly performing the heat treatment, the insulating film 250A, the oxide 230b, and the acid Hydrogen in compound 230a can be removed even more efficiently. The heat treatment temperature is as follows: It is preferable to use a temperature between 300°C and 500°C.

[0312] Furthermore, microwave treatment is performed to modify the film quality of insulating film 250A and insulating film 250B. This suppresses the diffusion of hydrogen, water, impurities, etc. Therefore, the conductor 260 and Through subsequent processes such as deposition of a conductive film or post-treatment such as heat treatment, the insulator 250 is used This suppresses the diffusion of hydrogen, water, impurities, etc., into oxide 230b, oxide 230a, etc. It is possible.

[0313] Next, a conductive film to become conductor 260a and a conductive film to become conductor 260b are deposited in sequence. The deposition of the conductive film that will become the conductive body 260a and the conductive film that will become the conductive body 260b is performed by sputtering. This can be carried out using methods such as CVD, MBE, PLD, and ALD. Morphologically, a conductive film that will become the conductor 260a is formed using the ALD method, and then the CVD method is used A conductive film that will become the conductor 260b is formed.

[0314] Next, CMP treatment is performed to create insulating film 250A, insulating film 250B, and conductive material 260a. Polish the conductive film and the conductive film that will become the conductor 260b until the insulator 280 is exposed. Therefore, insulator 250a, insulator 250b, and conductor 260 (conductor 260a, This forms an insulator (see Figures 17A to 17D). 250 is the inner wall (side wall, and) of the groove of oxide 230b, which reaches the opening and the inner wall (side wall, and It is positioned to cover the bottom surface. In addition, the conductor 260 is connected to the insulator 250, It is positioned to fill the opening and the groove mentioned above.

[0315] Next, a heat treatment may be performed under the same conditions as the heat treatment described above. In this embodiment, nitrogen The process is carried out at a temperature of 400°C for 1 hour in a plain atmosphere. This heat treatment causes the insulator 250 Furthermore, the moisture and hydrogen concentrations in the insulator 280 can be reduced. After heat treatment, the insulator 282 may be deposited continuously without exposure to the atmosphere.

[0316] Next, on the insulator 250, on the conductor 260, and on the insulator 280, insulator 282a Insulator 282b is formed continuously (see Figures 18A to 18D). Insulator 282 a and the film formation of the insulator 282b can be performed using a sputtering method, a CVD method, an MBE method, a PLD method , an ALD method, etc. The film formation of the insulator 282a and the insulator 282b is preferably performed using a sputtering method. Even if hydrogen is not used as the film formation gas , by using a sputtering method that does not require hydrogen, the hydrogen concentration in the insulator 282a and the insulator 282b [[ID=⑨]]can be reduced.

[0317] In the present embodiment, as the insulator 282a and the insulator 282b, aluminum oxide is formed by a pulsed DC sputtering method using an aluminum target in an atmosphere containing oxygen gas . By using the pulsed DC sputtering method, the film thickness distribution can be made more uniform , and the sputtering rate and film quality can be improved. Also, the RF power applied to the substrate is 1.86 W / cm or less. Preferably, it is 0 W / cm 2 or more and 0.31 W / cm 2 or less 2 . By reducing the RF power, the amount of oxygen injected into the insulator 280 can be suppressed . In the present embodiment, the insulator 282a is formed with the RF power applied to the substrate being 0 W / cm 2 , and the insulator 282b is formed with the RF power applied to the substrate being 0.31 W / cm 2 . <000282x)

[0318] Next, a part of the insulator 282a and a part of the insulator 282b are processed to form an opening region 400 (see Fig. 19D). In the opening region 400, the insulator 280 may have a concave portion . The processing of a part of the insulator 282a, a part of the insulator 282b, and a part of the insulator 280 may use wet etching, but dry etching is more suitable for fine processing This is preferable for processing. Also, the depth of the recess in the insulator 280 is favorable for the insulator 28 in the semiconductor device. The maximum film thickness should be between 1 / 4 and 1 / 2 of the maximum film thickness of 0.

[0319] Next, insulators 282a, 282b, 280, 272, and 222 , a portion of insulator 216 and a portion of insulator 214 reach the upper surface of insulator 212 The process is carried out using wet etching (see Figures 20A to 20C). While this method is also acceptable, dry etching is preferable for microfabrication.

[0320] Next, a heat treatment may be performed. The heat treatment should be performed at a temperature of 250°C to 650°C, preferably 4 The heat treatment should be carried out at a temperature between 00°C and 600°C. Furthermore, this heat treatment should be performed after the formation of the 243A oxide film. It is preferable that the temperature is lower than the heat treatment temperature. The heat treatment is performed using nitrogen gas or an inert gas. The process is carried out in a gas atmosphere. By performing this heat treatment, insulator 282a, insulator 282b, Processing of insulators 280, 272, 222, 216, and 214 As a result, oxygen contained in the insulator 280 and the side surface of the insulator 280 formed by this process Hydrogen combined with oxygen can be released to the outside. In addition, the insulator 280 contains Oxygen and hydrogen bound to that oxygen are released to the outside through the opening region 400. Yes, it is possible. Furthermore, hydrogen that combines with oxygen is released as water. Therefore, it is contained in insulator 280. This reduces unwanted oxygen and hydrogen. Furthermore, the heat treatment is performed in the opening region 40 This is done after the formation of 0, and further, insulators 280, 272, 222, and 216, This may also be done after processing the insulator 214.

[0321] Next, an insulator 283 is formed on the insulator 282b (see Figures 21A to 21D). It is preferable that the insulator 283 is in contact with the insulator 280 in the opening region 400. The film deposition of body 283 was performed by sputtering, CVD, MBE, PLD, or ALD. This can be done using methods such as the above. The insulator 283 is deposited using the sputtering method. It is preferable to use a sputtering method that does not require the use of hydrogen as the film deposition gas. The hydrogen concentration in the insulator 283 can be reduced. Also, the insulator 283 is multilayered. Alternatively, a silicon nitride film may be deposited using a sputtering method, and the silicon nitride On top of that, silicon nitride may be deposited using the ALD method. A highly barrier insulator 283 By encasing the transistor 200 in the insulator 212, moisture and hydrogen are prevented from entering from the outside. This can prevent intrusion.

[0322] Next, an insulator 274 is formed on the insulator 283 (see Figures 21B to 21D). The insulator 274 is deposited by sputtering, CVD, MBE, PLD, or AL This can be done using methods such as Method D. In this embodiment, the insulator 274 is subjected to CVD. A silicon oxide film is formed by this method.

[0323] Next, the insulator 274 is polished by CMP until the insulator 283 is exposed. This flattens the upper surface of the insulator 274 (see Figures 21B to 21D). The P treatment may remove a portion of the upper surface of the insulator 283. As a result, the opening region 400 is filled with a portion of the insulator 274 on the insulator 283. It will be done.

[0324] Next, an insulator 286 is formed on the insulator 274 and on the insulator 283 (Figure 21A). (See Figure 21D.) The insulator 286 was deposited by sputtering, CVD, or MBE. This can be done using methods such as the PLD method or the ALD method. In this embodiment, the insulator As 286, silicon oxide is deposited using the sputtering method.

[0325] Next, insulator 271, insulator 272, insulator 280, insulator 282, insulator 283, An opening is formed in the insulator 286 that reaches the conductor 242 (see Figures 21A and 21B). The opening can be formed using lithography. Note that in Figure 21A, The shape of the opening is circular when viewed from above, but it is not limited to this. For example... If the opening is, in a top view, roughly circular in shape such as an ellipse, polygonal in shape such as a quadrilateral, or quadrilateral The polygon may have rounded corners.

[0326] Next, an insulating film to become an insulator 241 is formed, and the insulating film is anisotropically etched to form an insulator. Form 241. (See Figure 21B.) The insulating film that will become the insulator 241 is deposited by sputtering. This can be done using methods such as the ring method, CVD method, MBE method, PLD method, or ALD method. The insulating film that will become the insulator 241 is an insulating film that has the function of suppressing oxygen permeation. It is preferable to have this. For example, it is preferable to deposit aluminum oxide using the ALD method. It is preferable to deposit silicon nitride using the PEALD method. Silicon is preferred because it has high blocking properties for hydrogen.

[0327] Furthermore, as an anisotropic etching of the insulating film that becomes the insulator 241, for example, dry etching Methods such as the G method can be used. By providing an insulator 241 on the side wall of the opening, oxygen from the outside can be blocked. This suppresses the transmission of the current and prevents oxidation of the conductors 240a and 240b that are to be formed next. This can be done. Also, impurities such as water and hydrogen can be removed from conductors 240a and 240b. It can prevent it from spreading to the outside.

[0328] Next, conductive films that will become conductor 240a and conductor 240b are formed. Conductive 240a The conductive film that forms the conductor 240b has the function of suppressing the permeation of impurities such as water and hydrogen. It is desirable to have a laminated structure that includes a conductive material. For example, tantalum nitride, titanium nitride, etc. It can be laminated with tungsten, molybdenum, copper, etc. Conductor 240 and The deposition of the conductive film can be done by sputtering, CVD, MBE, PLD, or ALD. This can be done using methods such as [mention specific methods].

[0329] Next, by performing CMP treatment, the conductive films that become conductor 240a and conductor 240b are formed. A portion is removed, exposing the upper surface of the insulator 274. As a result, the conductive film remains only in the opening. By providing this, it is possible to form conductors 240a and 240b with flat upper surfaces. (See Figure 21B.) Note that a portion of the upper surface of the insulator 286 is removed by the CMP treatment. There are cases where this can happen.

[0330] Next, a conductive film that will become conductor 246 is formed. The formation of the conductive film that will become conductor 246 is performed by This can be done using methods such as puttering, CVD, MBE, PLD, or ALD. can.

[0331] Next, a conductive film to become conductor 246 is processed by lithography, resulting in conductor 240a. The conductor 246a that is in contact with the upper surface of the conductor 240b, and the conductor 246b that is in contact with the upper surface of the conductor 240b Formed. Although not shown in the diagram, at this time, the conductor 246a and conductor 246b and the insulator 28 A portion of the insulator 286 in the region that does not overlap with 6 may be removed.

[0332] Based on the above, a semiconductor device having the transistor 200 shown in Figures 3A to 3D is fabricated. This is possible. As shown in Figures 6A to 21D, the semiconductor device shown in this embodiment can be manufactured. By using this manufacturing method, transistor 200 can be produced.

[0333] <Microwave Processing Equipment> The following describes a microwave processing apparatus that can be used in the above-mentioned semiconductor device fabrication method. I will explain.

[0334] First, Figure 2 shows the configuration of a manufacturing equipment that minimizes the inclusion of impurities during the manufacturing of semiconductor devices and other equipment. 2. This will be explained using Figures 23 and 24.

[0335] Figure 22 schematically shows a top view of the single-wafer multi-chamber manufacturing apparatus 2700. The manufacturing apparatus 2700 includes a cassette port 2761 for housing the substrate and a substrate alignment An alignment port 2762 for performing an atmospheric substrate supply chamber 2701 and an atmospheric substrate From the board supply room 2701, the substrate is transported to the atmospheric substrate transport room 2702, and the substrate is brought in. Furthermore, a load lock chamber that switches the pressure inside the room from atmospheric pressure to reduced pressure, or from reduced pressure to atmospheric pressure. 2703a, and the removal of the substrate, and the room pressure from reduced pressure to atmospheric pressure, or from atmospheric pressure Unload lock chamber 2703b for switching to reduced pressure, and transport chamber 2 for transporting substrates in vacuum. 704, chamber 2706a, chamber 2706b, chamber 2706c It has a chamber 2706d and

[0336] Furthermore, the atmospheric substrate transport chamber 2702 is connected to the load lock chamber 2703a and the unload lock chamber. It is connected to the loading lock chamber 2703b, and the load lock chamber 2703a and the unload lock chamber 270 3b is connected to transport chamber 2704, and transport chamber 2704 is connected to chamber 2706a, It connects to bar 2706b, chamber 2706c, and chamber 2706d.

[0337] Furthermore, gate valves GV are provided at the connection points of each chamber, and the atmospheric substrate supply chamber 270 Except for chamber 1 and the atmospheric substrate transport chamber 2702, each chamber can be independently maintained in a vacuum state. Furthermore, a transport robot 2763a is provided in the atmospheric substrate transport chamber 2702, and transport A transport robot 2763b is installed in the transport room 2704. The transport robot 2763b can transport the substrates within the manufacturing apparatus 2700. ru.

[0338] The back pressure (total pressure) in the transport chamber 2704 and each chamber is, for example, 1 × 10⁻⁶ -4 Pa or less Preferably 3 × 10 -5 Pa or less, more preferably 1 × 10⁻⁶ -5 It should be Pa or less. Furthermore, the mass-to-charge ratio (m / z) of the transport chamber 2704 and each chamber is 18 for gas molecules. The partial pressure of an atom is, for example, 3 × 10⁻¹⁰ -5 Pa or less, preferably 1 × 10⁻⁶ -5 Pa and below, More preferably 3 × 10 -6 The Pa level should be less than or equal to the Pa level. Also, the transport chamber 2704 and each chamber. The partial pressure of a gas molecule (atom) with a m / z of 28 is, for example, 3 × 10⁻¹⁰ -5 Pa or below preferred Or 1 x 10 -5 Pa or less, more preferably 3 × 10 -6 It shall be less than Pa. The partial pressure of gas molecules (atoms) in supply chamber 2704 and each chamber with a m / z of 44 is, for example, ba, 3 x 10 -5 Pa or less, preferably 1 × 10⁻⁶ -5 Pa or less, more preferably 3 × 1 0 -6 It should be Pa or less.

[0339] The total pressure and partial pressure in the transport chamber 2704 and each chamber were measured using a mass spectrometer. It can be measured. For example, with a quadrupole mass spectrometer (Q-mas) manufactured by ULVAC, Inc. Also called s.) You can use Qulee CGM-051.

[0340] Furthermore, the transport chamber 2704 and each chamber are constructed to minimize external or internal leaks. It is desirable to make it a set. For example, the leak rate of the transport chamber 2704 and each chamber is , 3 x 10 -6 Pa·m 3 / s or less, preferably 1 × 10 -6 Pa·m 3 Set to / s or less. Also, for example, the leak rate of a gas molecule (atom) with m / z 18 is 1 × 10⁻⁶. -7 P a·m 3 / s or less, preferably 3 × 10 -8 Pa·m 3 It should be less than or equal to / s. Also, for example, The leak rate of a gas molecule (atom) with m / z 28 is 1 × 10⁻⁶ -5 Pa·m 3 / s or less Preferably 1 × 10 -6 Pa·m 3 It should be less than or equal to / s. Also, for example, if m / z is 44 The leak rate of gas molecules (atoms) is 3 × 10 -6 Pa·m 3 / s or less, preferably 1× 10 -6 Pa·m 3 Set to / s or less.

[0341] Regarding the leak rate, the total pressure and partial pressure were measured using the aforementioned mass spectrometer. Then we can derive it. The leak rate depends on external leaks and internal leaks. The problem is the inflow of gas from outside the vacuum system due to tiny holes or sealing defects. Leaks are caused by leaks from valves or other partitions within the vacuum system, or by released gases from internal components. To keep the leak rate below the above-mentioned values, both external and internal leaks are addressed. Therefore, countermeasures need to be taken.

[0342] For example, the opening and closing parts of the conveying chamber 2704 and each chamber are sealed with metal gaskets. It is good to do so. Metal gaskets are made of iron fluoride, aluminum oxide, or chromium oxide. It is preferable to use a metal gasket that is coated. Metal gaskets have better adhesion than O-rings. External leakage can be reduced. Also, by using iron fluoride, aluminum oxide, chromium oxide, etc. By using a metal passivation coating, impurities released from the metal gasket are contained. This suppresses the release of gases and reduces internal leakage.

[0343] Furthermore, as a component of the manufacturing apparatus 2700, aluminum with low emission gas containing impurities is used. It uses nium, chromium, titanium, zirconium, nickel, or vanadium. Also, the previous A metal with low emission gases containing the aforementioned impurities is coated onto an alloy containing iron, chromium, nickel, etc. It may also be used in reverse. Alloys containing iron, chromium, and nickel are rigid and heat resistant. Furthermore, it is suitable for processing. Here, in order to reduce the surface area, the surface irregularities of the material are polished. By reducing these factors, the amount of emitted gas can be reduced.

[0344] Alternatively, the components of the aforementioned manufacturing apparatus 2700 may be made of iron fluoride, aluminum oxide, chromium oxide, etc. Any covering will do.

[0345] The components of the manufacturing apparatus 2700 are preferably made of metal as much as possible, such as quartz. When installing viewing windows or similar devices, the surface should be treated with iron fluoride to suppress the release of gases. It is best to coat it thinly with aluminum oxide, chromium oxide, or similar materials.

[0346] The adsorbed material present in the transport chamber 2704 and each chamber is adsorbed to the inner walls, etc. This does not affect the pressure in the transport chamber 2704 and each chamber, however, the pressure in the transport chamber 2704 and each chamber This causes gas release when exhausting the chamber. Therefore, the leak rate and exhaust speed are related. Although there is no direct connection, a pump with high exhaust capacity is used to transport chamber 2704 and each chamber. It is important to remove as much of the adsorbed material as possible and to evacuate the system beforehand. To promote the desorption of adsorbed material, the transport chamber 2704 and each chamber may be baked. Baking can increase the desorption rate of adsorbed substances by about 10 times. The process should be carried out at a temperature between 100°C and 450°C. At this time, an inert gas is introduced into the transport chamber 2704. Furthermore, when adsorbed substances are removed while being introduced into each chamber, they are difficult to remove by exhaust alone. The desorption rate of water and other substances can be further increased. By heating it to a temperature similar to that of King, the desorption rate of adsorbed substances can be further increased. It is preferable to use a noble gas as the inert gas in this case.

[0347] Alternatively, by introducing an inert gas such as a heated noble gas or oxygen into the transport chamber 27 The pressure in 04 and each chamber is increased, and after a certain period of time, the transfer chamber 2704 and each It is preferable to perform a process to exhaust the chamber. By introducing heated gas into the conveying chamber 2704 And adsorbed material can be removed from each chamber, transport chamber 2704 and each chamber This process can reduce impurities present in the bar. Note that this process should be repeated between 2 and 30 times. It is more effective to repeat the procedure, preferably between 5 and 15 times. Specifically, warm An inert gas whose temperature is between 40°C and 400°C, preferably between 50°C and 200°C. By introducing oxygen, etc., the pressure inside the transport chamber 2704 and each chamber can be raised to 0.1 Pa or less. Above 10 kPa or less, preferably 1 Pa or more and 1 kPa or less, more preferably 5 Pa or more and 1 The pressure should be 00 Pa or less, and the period for maintaining the pressure should be 1 minute or more and 300 minutes or less, preferably 5 minutes or more and 120 minutes or less. It should be less than a minute. After that, transport chamber 2704 and each chamber should be kept for 5 minutes to 300 minutes. Preferably, exhaust the system for a period of 10 minutes to 120 minutes.

[0348] Next, the cross-sectional model of chambers 2706b and 2706c is shown in Figure 23. I will explain using a diagram.

[0349] Chambers 2706b and 2706c are, for example, used to apply microwaves to the workpiece. This is a chamber capable of performing processing. Note that chamber 2706b and chamber The only difference between this and the 2706c is the atmosphere used during microwave processing. Other configurations Since these points are common to all, they will be explained together below.

[0350] Chambers 2706b and 2706c are connected to slot antenna board 2808. It has a dielectric plate 2809, a substrate holder 2812, and an exhaust port 2819. Outside chambers 2706b and 2706c, etc., there is a gas supply source 2801 and Valve 2802, high-frequency generator 2803, waveguide 2804, and mode converter 2805 And gas tube 2806, waveguide 2807, matching box 2815, and high-frequency power supply. A 2816, a vacuum pump 2817, and a valve 2818 are provided.

[0351] The high-frequency generator 2803 is connected to the mode converter 2805 via the waveguide 2804. The mode converter 2805 is connected to the slot antenna plate 2808 via the waveguide 2807. It continues. The slot antenna plate 2808 is positioned in contact with the dielectric plate 2809. Furthermore, the gas supply source 2801 is connected to the mode converter 2805 via the valve 2802. And the gas passes through the mode converter 2805, waveguide 2807 and dielectric plate 2809. Gas is supplied to chambers 2706b and 2706c via tube 2806. Furthermore, the vacuum pump 2817 is connected to the valve 2818 and exhaust port 2819. It has the function of exhausting gases, etc., from chamber 2706b and chamber 2706c. Furthermore, the high-frequency power supply 2816 is connected to the board holder 2812 via the matching box 2815. Connecting.

[0352] The substrate holder 2812 has the function of holding the substrate 2811. For example, substrate 2811 It has the function of electrostatically or mechanically chucking. Also, high-frequency power supply 2816 or It functions as an electrode to which power is supplied. It also has a heating mechanism 2813 inside. It has a function to heat the substrate 2811.

[0353] Vacuum pump 2817 can be used in various ways, such as dry pumps and mechanical booster pumps. Ion pumps, titanium sublimation pumps, cryopumps, or turbomolecular pumps These can be used. In addition, a cryotrap can be used in addition to the vacuum pump 2817. It is acceptable. Using a cryopump and cryotrap allows for efficient water exhaust. This is particularly preferable.

[0354] Furthermore, the heating mechanism 2813 may be a heating mechanism that uses, for example, a resistance heating element. Alternatively, by heat conduction or thermal radiation from a medium such as a heated gas, It may also be used as a heating mechanism. For example, GRTA (Gas Rapid Thermature) (Lamp Annealing) or LRTA (Lamp Rapid Thermal A RTA (Rapid Thermal Annealing) such as annealing This can be used. GRTA performs heat treatment using high-temperature gas. An inert gas is used.

[0355] Furthermore, the gas supply source 2801 is connected to the purifier via a mass flow controller. It is acceptable to use a gas with a dew point of -80°C or lower, preferably -100°C or lower. It is preferable to use oxygen gas, nitrogen gas, and noble gases (such as argon gas). Use it.

[0356] Examples of dielectric plates 2809 include silicon oxide (quartz) and aluminum oxide (aluminum oxide). Mina or yttrium oxide (yttria) can be used. Also, dielectric plate 28 Another protective layer may be formed on the surface of 09. The protective layer may be magnesium oxide. Zium, titanium dioxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, Dielectric plate: Silicon oxide, aluminum oxide, or yttrium oxide can be used. 2809 will be exposed to the particularly high-density region of the high-density plasma 2810, which will be described later. Therefore, damage can be mitigated by providing a protective layer. As a result, particles during processing This can suppress increases in the number of cases, etc.

[0357] The high-frequency generator 2803 can handle frequencies such as 0.3 GHz to 3.0 GHz, and 0.7 GHz. Generates microwaves between z and 1.1 GHz, or between 2.2 GHz and 2.8 GHz. It has the function of causing the microwaves generated by the high-frequency generator 2803 to be transmitted to the waveguide 2804. This is transmitted to the mode converter 2805 via [a certain method]. In the mode converter 2805, the TE mode is [a certain method]. The transmitted microwaves are converted to TEM mode. Then, the microwaves are transmitted through waveguide 280. It is transmitted to the slot antenna board 2808 via 7. The slot antenna board 2808 has multiple A slot hole is provided, and microwaves pass through the slot hole and the dielectric plate 2809. Then, an electric field is generated below the dielectric plate 2809, and the high-density plasma 2810 It can be generated. The high-density plasma 2810 is supplied from the gas supply source 2801. Depending on the type of gas, ions and radicals exist. For example, oxygen radicals exist. ru.

[0358] At this time, the substrate 2811 is exposed to ions and radicals generated in the high-density plasma 2810. This allows for modification of films on substrate 2811. Furthermore, the high-frequency power supply 2816 It may be preferable to apply a bias to the substrate 2811 side using the high-frequency power supply 28 For example, using an RF power supply with frequencies such as 13.56MHz or 27.12MHz. This is all that's needed. By applying a bias to the substrate side, the ions in the high-density plasma 2810 are used as the base This allows the material to efficiently reach deep into openings such as those in membranes on plate 2811.

[0359] For example, in chamber 2706b or chamber 2706c, gas supply source 2801 or By introducing oxygen, oxygen radical treatment using high-density plasma 2810 can be performed. can.

[0360] Next, the cross-sectional model of chambers 2706a and 2706d is shown in Figure 24. I will explain using a diagram.

[0361] Chambers 2706a and 2706d are, for example, used to expose the workpiece to electromagnetic waves. This is a chamber capable of firing. Note that chamber 2706a and chamber 2 The only difference between the 706d and this model is the type of electromagnetic wave they use. Other components are the same. Since there is a lot of information, the following explanation will be summarized.

[0362] Chambers 2706a and 2706d are one or more lamps 2820 It also includes a substrate holder 2825, a gas inlet 2823, and an exhaust port 2830. Outside of chambers 2706a and 2706d, etc., there is a gas supply source 2821 Valve 2822, vacuum pump 2828, and valve 2829 are provided.

[0363] The gas supply source 2821 is connected to the gas inlet 2823 via a valve 2822. The vacuum pump 2828 is connected to the exhaust port 2830 via valve 2829. 2820 is positioned opposite the board holder 2825. The board holder 2825 is It has the function of holding the substrate 2824. The substrate holder 2825 also has a heating mechanism inside. It has a component 2826 and a function to heat the substrate 2824.

[0364] Lamp 2820, for example, has a function that emits electromagnetic waves such as visible light or ultraviolet light. Any light source with the necessary properties can be used. For example, wavelengths between 10 nm and 2500 nm, and between 500 nm. It emits electromagnetic waves with a peak above 2000 nm or below, or between 40 nm and 340 nm. A light source with the necessary functionality should be used.

[0365] For example, lamp 2820 could be a halogen lamp, a metal halide lamp, or a xenon lamp. Arc lamps, carbon arc lamps, high-pressure sodium lamps, or high-pressure mercury lamps, etc. You can use this light source.

[0366] For example, some or all of the electromagnetic waves emitted from lamp 2820 are transmitted to substrate 2824 By being absorbed, the film on the substrate 2824 can be modified. For example, the birth of defects It is possible to create or reduce impurities, or remove them. Note that while heating the substrate 2824 This process allows for efficient generation or reduction of defects, or removal of impurities.

[0367] Alternatively, for example, electromagnetic waves emitted from lamp 2820 may affect the substrate holder 2825 The circuit board 2824 may be heated by adding heat to the inside of the circuit board holder 2825. It is not necessary to have a thermal mechanism 2826.

[0368] For vacuum pump 2828, refer to the description for vacuum pump 2817. Also, heating machine Structure 2826 refers to the description of the heating mechanism 2813. Also, gas supply source 2821 See the description for gas source 2801.

[0369] By using the above manufacturing equipment, it is possible to suppress the contamination of the workpiece with impurities while modifying the film. This will become possible.

[0370] <Modified examples of semiconductor devices> In the following, using Figures 25A to 28B, an example of a semiconductor device according to one aspect of the present invention will be shown. I will explain about that.

[0371] Each Figure A shows a top view of a semiconductor device. Each Figure B shows a point A1-A2 shown in Figure A. This is a cross-sectional view corresponding to the area indicated by the dashed line. Also, each Figure C is a single dotted line from A3-A4 to the corresponding Figure A. This is a cross-sectional view corresponding to the area indicated by the line. Also, each Figure D is a cross-sectional view of the area indicated by the dashed line A5-A6 in each Figure A. This is a cross-sectional view corresponding to the part indicated by the arrow. In each top view of Figure A, some parts are shown for clarity. It omits the essentials.

[0372] Furthermore, in the semiconductor devices shown in Figures A to D, the semiconductors shown in <Example of Semiconductor Device Configuration> are... Structures that have the same function as the structures constituting the body device shall be denoted with the same reference numeral. However, the constituent materials of semiconductor devices are described in detail in <Examples of Semiconductor Device Configurations>. You can use it.

[0373] <Example 1 of a semiconductor device> The semiconductor devices shown in Figures 25A to 25D are variations of the semiconductor devices shown in Figures 3A to 3D. This is an example. The semiconductor device shown in Figures 25A to 25D is the same as the semiconductor device shown in Figures 3A to 3D. The body device differs in that it contains oxide 230c and oxide 230d.

[0374] In the semiconductor device shown in Figures 25A to 25D, further, oxide 23 on oxide 230b It comprises oxide 230c and oxide 230d on oxide 230c. Oxide 230c and oxide 230d is provided within the openings formed in the insulators 280 and 272. Furthermore, oxide 230c is on the side surface of oxide 243a, on the side surface of oxide 243b, and conductor 242a The sides of the conductor 242b, the sides of the insulator 271a, the sides of the insulator 271b, and It is in contact with the sides of the insulator 272. Also, the upper surface of oxide 230c and oxide 23 The upper surface of 0d is in contact with the insulator 282.

[0375] By placing oxide 230d on top of oxide 230c, above oxide 230d Diffusion of impurities from the structure formed therein into oxide 230b or oxide 230c This can be suppressed. Also, by placing oxide 230d on top of oxide 230c Therefore, upward diffusion of oxygen from oxide 230b or oxide 230c can be suppressed. .

[0376] Furthermore, in a cross-sectional view of the transistor in the channel length direction, grooves are provided in the oxide 230b. It is preferable to embed oxide 230c in the groove. At this time, oxide 230c is It is positioned to cover the inner wall (side wall and bottom surface) of the groove. Also, oxide 230c The film thickness is preferably about the same as the depth of the groove. When forming an opening for embedding the conductor 260, the oxide 2 at the bottom of the opening Even if a damaged area is formed on the surface of 30b, the damaged area can be removed. This makes it possible to suppress electrical defects in transistor 200 caused by the damaged area. .

[0377] Here, the atomic ratio of In to element M in the metal oxide used for oxide 230c However, in the metal oxide used in oxide 230a or oxide 230d, with respect to element M It is preferable that the atomic ratio is greater than that of In.

[0378] Furthermore, if oxide 230c is the primary carrier pathway, Therefore, the atomic ratio of indium to the main component metal element in oxide 230b is, It is preferable that the atomic ratio of indium to the main metal element is greater than that of the main metal element. In oxide 230c, the atomic ratio of In to element M is the same as in oxide 230b, It is preferable that the atomic ratio of In to element M is greater than that of gold with a high indium content. By using a specific oxide in the channel formation region, the on-current of the transistor can be increased. Yes, it is possible. Therefore, in oxide 230c, the relationship between indium and the main metal element is The atomic ratio is the ratio of indium atoms to the main metal element in oxide 230b. By making the ratio greater than the numerical ratio, oxide 230c can be made the primary carrier pathway. Furthermore, the lower end of the conduction band of oxide 230c is the conduction band of oxide 230a and oxide 230b. It is preferable that the lower edge of the band is further away from the vacuum level. In other words, the electric field of oxide 230c The electron affinity is preferably greater than the electron affinity of oxides 230a and 230b. i. In this case, the main carrier pathway is oxide 230c.

[0379] Specifically, as oxide 230c, In:M:Zn = 4:2:3 [atomic ratio] or This refers to compositions in the vicinity of that, In:M:Zn=5:1:3 [atomic ratio] or compositions in the vicinity of that, Alternatively, metal oxides with a composition of In:M:Zn = 10:1:3 [atomic ratio] or close to that. Using indium oxide or similar materials is recommended.

[0380] Furthermore, it is preferable to use CAAC-OS as oxide 230c, and oxide 230 The c-axis of the crystal of c is oriented in a direction approximately perpendicular to the surface or top surface of the oxide 230c. It is preferable that CAAC-OS has the property of easily moving oxygen in the direction perpendicular to the c-axis. It has such properties. Therefore, it efficiently supplies the oxygen contained in oxide 230c to oxide 230b. It is possible.

[0381] Furthermore, oxide 230d is a metal element that makes up the metal oxide used in oxide 230c. Preferably, it contains at least one of the metal elements, and more preferably, it contains all of them. For example, as oxide 230c, In-M-Zn oxide, In-Zn oxide, or In Using zinc oxide, as oxide 230d, In-M-Zn oxide, M-Zn oxide, Alternatively, an oxide of element M may be used. This will produce oxide 230c and oxide 230d. The defect level density at the interface can be reduced.

[0382] Furthermore, the lower end of the conduction band of oxide 230d is closer to the vacuum level than the lower end of the conduction band of oxide 230c. It is preferable that the electron affinity of oxide 230d is equal to the electron affinity of oxide 230c. It is preferable that it is smaller than the affinity of the offspring. In this case, oxide 230d is also oxide 230a It is preferable to use a metal oxide that can be used for oxide 230b. The primary carrier pathway is oxide 230c.

[0383] Specifically, as oxide 230c, In:M:Zn = 4:2:3 [atomic ratio] or This refers to compositions in the vicinity of that, In:M:Zn=5:1:3 [atomic ratio] or compositions in the vicinity of that, Alternatively, metal oxides with a composition of In:M:Zn = 10:1:3 [atomic ratio] or close to that. Alternatively, indium oxide can be used. Also, as oxide 230d, In:M: Zn = 1:3:4 [atomic ratio] or a composition close to that, M:Zn = 2:1 [atomic ratio] Or a composition in the vicinity of that, or M:Zn=2:5 [atomic ratio] or a composition in the vicinity of that. A metal oxide or an oxide of element M may be used. Note that the nearby composition refers to the desired composition. It includes a range of ±30% of the atomic ratio. Furthermore, it is preferable to use gallium as element M. stomach.

[0384] Furthermore, oxide 230d is a metal that suppresses oxygen diffusion or permeation more effectively than oxide 230c. It is preferable that it be an oxide. Oxide 230d is placed between the insulator 250 and oxide 230c. By providing this, oxygen can be efficiently supplied to oxide 230b via oxide 230c. It is possible.

[0385] Furthermore, in the metal oxide used in oxide 230d, the I250 is the main component of the metal element. The atomic ratio of n is determined based on the main metal element in the metal oxide used in oxide 230c. By making the atomic ratio of In smaller than that of In, the diffusion of In towards the insulator 250 is suppressed. This can be done. For example, in oxide 230d, the atomic ratio of In to element M is The ratio should be smaller than the atomic ratio of In to element M in oxide 230c. Body 250 functions as a gate insulator, so if In gets mixed into insulator 250, This results in a transistor characteristic defect. Therefore, between the oxide 230c and the insulator 250 By providing oxide 230d, it becomes possible to provide a highly reliable semiconductor device.

[0386] Note that oxide 230c may be provided for each transistor 200. The oxide 230c of transistor 200 and the adjacent transistor 200 It is not necessary for the oxide 230c to come into contact with the transistor 200. And, the oxide 230c of the transistor 200 adjacent to the transistor 200, They may be separated. In other words, oxide 230c is connected to transistor 200 and the transistor It is also possible to configure it so that it is not placed between transistor 200 and an adjacent transistor 200.

[0387] In a semiconductor device in which multiple transistors 200 are arranged in the channel width direction, With this configuration, oxide 230c is provided independently for each transistor 200. Therefore, transistor 200 and transistor 2 adjacent to transistor 200. This suppresses the formation of parasitic transistors between 00 and 00, and prevents the formation of the above-mentioned leakage path. Therefore, it is possible to have good electrical properties and miniaturize or highly integrate it. We can provide a suitable semiconductor device.

[0388] <Modified example of a semiconductor device 2> Below, using Figures 26A and 26B, we will show an example of a semiconductor device according to one aspect of the present invention. I will explain this.

[0389] Figure 26A shows a top view of the semiconductor device. Figure 26B shows the A3-A4 shown in Figure 26A. This is a cross-sectional view corresponding to the area indicated by the dashed line in Figure 26A. Note that the dashed line A1-A2 is shown in Figure 26A. The cross-sectional view corresponding to the indicated part can be found by referring to transistor 200 shown in Figure 3B. Note that some elements have been omitted in the top view of Figure 26A for clarity.

[0390] Furthermore, in the semiconductor device shown in Figures 3A to 3D, the configuration shown in <Example of semiconductor device configuration> is as follows. Structures that have the same function as structures constituting a semiconductor device are denoted by the same reference numeral. However, the constituent materials of semiconductor devices are explained in detail in <Examples of Semiconductor Device Configurations>. Materials can be used.

[0391] The semiconductor device shown in Figures 26A and 26B is the same as the semiconductor device shown in Figures 3A to 3D. This is a modified example. In the semiconductor device shown in Figures 26A and 26B, transistor 200 It has n oxide 230 (oxide 230_1 to oxide 230_n: n is a natural number) The configuration differs from that of the semiconductor device shown in Figures 3A to 3D. Also, each oxide 230_1 to oxide Each of the objects 230_n has a channel-forming region.

[0392] The semiconductor device shown in Figures 26A and 26B has multiple channel formation regions on the top and side surfaces. A conductor 260 is provided via an insulator 250. Also, a conductor 246 (conductor 246a and conductor 246b) are stretched in the A3-A4 direction, and conductor 240 Through this, it is electrically connected to oxides 230_1 to 230_n.

[0393] In other words, in the semiconductor device shown in Figures 26A and 26B, transistor 200 is A single gate electrode has multiple channel formation regions. Figures 26A and 26B show The transistor 200 shown has multiple channel formation regions, thereby obtaining a large on-current. It is possible to do so. In addition, each channel-forming region is a structure covered with a gate electrode, Because it has an s-channel structure, each channel formation region is large A large on-current can be obtained. Alternatively, in the channel width direction of transistor 200 And, with the bottom surface of the insulator 222 as the reference, the conductor 260 and oxide 2 The height of the bottom surface of the region that does not overlap with 30b is the height between the top surface of the oxide 230b and the insulator 250. Because it is lower than the interface height, a large on-current can be obtained in each channel formation region. It is possible.

[0394] Furthermore, other configurations may be determined by referring to the semiconductor device configurations shown in Figures 3A to 3D. can.

[0395] <Modified example of semiconductor device 3> Below, using Figures 27A and 27B, we will show an example of a semiconductor device that is one embodiment of the present invention. I will explain this.

[0396] Figure 27A shows a top view of the semiconductor device. Figure 27B shows the A3-A4 shown in Figure 27A. This is a cross-sectional view corresponding to the area indicated by the dashed line in Figure 27A. Note that the dashed line A1-A2 is shown in Figure 27A. The cross-sectional view corresponding to the indicated part can be found by referring to transistor 200 shown in Figure 3B. Note that some elements have been omitted in the top view of Figure 27A for clarity.

[0397] In addition, in the semiconductor device shown in Figures 27A and 27B, <Example of semiconductor device configuration> Structures having the same function as the semiconductor device shown will be denoted by the same reference numeral. In this section as well, the constituent materials of semiconductor devices are explained in detail in <Examples of Semiconductor Device Configurations>. The materials specified can be used.

[0398] The semiconductor device shown in Figures 27A and 27B is the same as the semiconductor device shown in Figures 26A and 26B. This is a modified example of the apparatus. In the semiconductor device shown in Figures 27A and 27B, a transistor 200 represents n oxides 230 (oxide 230_1 to oxide 230_n: n is a natural number). It has. In addition, each oxide 230_1 to oxide 230_n has a channel-forming region. It has a region.

[0399] The semiconductor device shown in Figures 27A and 27B has multiple channel formation regions on the top and side surfaces. A conductor 260 is provided via an insulator 250. Also, a conductor 246 (conductor 246a and conductor 246b) are stretched in the A3-A4 direction, and conductor 240 Through this, it is electrically connected to oxides 230_1 to 230_n.

[0400] The semiconductor device shown in Figures 27A and 27B has multiple channel formation regions. Transistor 200 has transistors 200D on both sides. Adjacent to the placed oxide 230_1, a transient having at least oxide 230_D Place the 200D. Similarly, place the oxide 230_ at the end of the transistor 200. The transistor 200D is placed adjacent to n.

[0401] In other words, the semiconductor device shown in Figures 27A and 27B has multiple transistors 200 A configuration in which transistors 200D are provided at one end or both ends in the direction in which the channel formation regions are parallel. The semiconductor device differs from those shown in Figures 26A and 26B in that it has the following characteristics:

[0402] Here, transistor 200D has gate wiring, source wiring, or drain wiring. It is not necessary to electrically connect to one or all of them. In other words, transistor 200D In some cases, transistors are installed in a non-functional state. Therefore, The ZISTA200D is sometimes referred to as a dummy transistor (sacrificial transistor).

[0403] Also, the shortest distance between oxide 230_D and oxide 230_1, and the distance between oxide 230_1 and oxide The shortest distance to substance 230_2 is preferably approximately equal. Similarly, oxide 230_ The shortest distance between D and oxide 230_n, and the shortest distance between oxide 230_n-1 and oxide 230_n. For short distances, it is preferable that they be approximately equal. Note that if n is 1, one of the oxides 2 The shortest distance between 30_D and oxide 230_1, and the other distance between oxide 230_D and oxide 230_ The shortest distance to 1 is preferably approximately equal.

[0404] Furthermore, the shortest distance between conductor 242a and conductor 242b in oxide 230_D is the acid The shortest distance between conductor 242a and conductor 242b in compound 230_1 is approximately equal to It may be or even larger. Similarly, conductor 24 in oxide 230_D The shortest distance between 2a and conductor 242b is the distance between conductor 242a and conductor in oxide 230_n. The shortest distance to body 242b may be approximately equal to, or greater than, this distance.

[0405] When multiple oxides 230 are formed in parallel, the oxides 230 located at the ends are affected during processing. This makes it more prone to variations in shape. Also, some of the insulator 280 and the oxide 230 The layered structure on the channel-forming region is removed to create an opening, exposing a portion of the upper surface of the oxide 230. In the process, the edge shape of the area to be removed (also called the opening), or the relationship between the oxide 230 and the opening Due to variations in factors such as the distance from the edges, there is variation in the area of ​​the exposed upper surface of oxide 230. This may occur.

[0406] Therefore, as shown in Figures 27A and 27B, by providing transistor 200D, If a shape defect occurs in the oxide 230_D of transistor 200D, or if the oxide Even if a shape defect occurs in the opening on 230_D, the region sandwiched between transistors 200D The shape of the oxide 230 formed thereon is homogeneous.

[0407] Therefore, by placing transistor 200D adjacent to transistor 200, multiple When a transistor 200 is provided, the variation in characteristics among multiple transistors 200 It can reduce the amount of noise.

[0408] Furthermore, if multiple oxides 230 are provided at equal intervals in a certain area, the wiring layout will be changed. This makes circuit design easier.

[0409] Furthermore, in the semiconductor device shown in Figures 27A and 27B, transistor 200 is Each gate electrode has multiple channel-forming regions, as shown in Figures 27A and 27B. Transistor 200 obtains a large on-current by having multiple channel formation regions. This is possible. In addition, each channel-forming region is a structure covered with a gate electrode, that is, Because it has an s-channel structure, each channel formation region is large A suitable on-current can be obtained. Alternatively, in the channel width direction of transistor 200 , with the bottom surface of the insulator 222 as the reference, the conductor 260 and the oxide 23 The height of the bottom surface of the region that does not overlap with 0b is the boundary between the top surface of oxide 230b and insulator 250. Because it is lower than the surface height, a large on-current can be obtained in each channel formation region. It is possible.

[0410] Furthermore, other configurations may be determined by referring to the semiconductor device configurations shown in Figures 3A to 3D. can.

[0411] <Modification 4 of semiconductor device> Below, using Figures 28A and 28B, we will show an example of a semiconductor device according to one aspect of the present invention. I will explain this.

[0412] Figure 28A shows a top view of the semiconductor device. Figure 28B shows the section A3-A4 shown in Figure 28A. This is a cross-sectional view corresponding to the area indicated by the dashed line in Figure 28A. Note that the dashed line A1-A2 is shown in Figure 28A. The cross-sectional view corresponding to the indicated part can be found by referring to transistor 200 shown in Figure 3B. Note that some elements have been omitted in the top view of Figure 28A for clarity.

[0413] In addition, in the semiconductor device shown in Figures 28A and 28B, the <Example of Semiconductor Device Configuration> is Structures having the same function as the semiconductor device shown will be denoted by the same reference numeral. In this section as well, the constituent materials of semiconductor devices are explained in detail in <Examples of Semiconductor Device Configurations>. The materials specified can be used.

[0414] The semiconductor device described in this section is the semiconductor device shown in Figures 27A and 27B. This is a modified example. Transistor 200 has an oxide 230 having n channel formation regions. Note that the n channel-forming regions are channel-forming region 235_1 to channel-forming region 2 The semiconductor shown in Figures 27A and 27B has 35_n (where n is a natural number). It differs from the device. Also, multiple channel formation regions have an insulator 250 on their upper and side surfaces. A conductor 260 is provided.

[0415] Furthermore, the conductor 242 (conductor 242a and conductor 242b) extends in the A3-A4 direction. It is stretched, and through the conductor 240 (conductor 240a and conductor 240b), the conductor It is electrically connected to 246 (conductors 246a and 246b).

[0416] Here, Figures 28A and 28B show the case where n=2 for the sake of simplicity. Therefore, transistor 200 has two channel formation regions (channel formation region 235_1 The oxide 230 has a channel-forming region 235_2).

[0417] In oxide 230, the source region and the drain region are made of conductor 242a, or conductor It is electrically connected to the electric body 242b. Therefore, for example, conductor 242a and conductor 24 By electrically connecting 6a and at least one conductor 240a, multiple In the channel formation region (channel formation region 235_1 to channel formation region 235_n), Pressure can be applied.

[0418] In other words, for a transistor 200 having n channel formation regions 235, it is not necessarily It is not necessary to provide n conductors 240. A transistor having n channel-forming regions 235 With respect to the zista, the number of conductors 240 is 1 or more, preferably 1 or more and less than n. It seems so.

[0419] Furthermore, as transistors become smaller, the conductor that functions as wiring to the transistor is electrically... The size of the plug that connects via gas also needs to be miniaturized. The reduced contact area between the body and the conductive material that functions as wiring increases the wiring resistance. There is a tendency.

[0420] In the semiconductor device described in this section, a transistor having n channel formation regions To provide a number of plugs less than n for 200, conductor 2 functions as a plug. Each of the 40 sizes is, for example, the conductive material 24 shown in the semiconductor device in Figures 27A and 27B. Since it is possible to make it greater than 0, power consumption can be reduced.

[0421] Furthermore, the semiconductor device shown in Figures 28A and 28B has multiple channel formation regions. Transistor 200 has transistors 200D on both sides. Adjacent to oxide 230_1 arranged in the section, there is a section having at least oxide 230_D. Place transistor 200D. Similarly, place oxide 2 at the end of transistor 200. Place transistor 200D adjacent to 30_2.

[0422] Therefore, the semiconductor device shown in Figures 28A and 28B has multiple channel formation regions on its upper surface. A conductor 260 is provided on the side surface via an insulator 250. Also, a conductor 246 a, and conductor 246b are stretched in the A3-A4 direction, and the oxide 230_2 and electrical Connect to the target.

[0423] Furthermore, the semiconductor device shown in Figures 28A and 28B has multiple channel formation regions. Transistor 200 has transistors 200D on both sides. Adjacent to the channel-forming region 235_1 located in the section, at least oxide 230_D The transistor 200D is positioned. Similarly, it is positioned at the end of transistor 200. A transistor 200D is placed adjacent to the channel formation region 235_n.

[0424] In other words, one end of the direction in which the multiple channel formation regions of transistor 200 are arranged in parallel, or A 200D transistor is placed at both ends.

[0425] Here, transistor 200D has gate wiring, source wiring, or drain wiring. It is not necessary to electrically connect to one or all of them. In other words, transistor 200D In some cases, transistors are installed in a non-functional state. Therefore, The ZISTA200D is sometimes referred to as a dummy transistor (sacrificial transistor).

[0426] Also, the shortest distance between oxide 230_D and oxide 230_1, and the distance between oxide 230_1 and oxide The shortest distance to substance 230_2 is preferably approximately equal. Similarly, oxide 230_ The shortest distance between D and oxide 230_n, and the shortest distance between oxide 230_n-1 and oxide 230_n. For short distances, it is preferable that they be approximately equal. Note that if n is 1, one of the oxides 2 The shortest distance between 30_D and oxide 230_1, and the other distance between oxide 230_D and oxide 230_ The shortest distance to 1 is preferably approximately equal.

[0427] Furthermore, the shortest distance between conductor 242a and conductor 242b in oxide 230_D is the acid The shortest distance between conductor 242a and conductor 242b in compound 230_1 is approximately equal to It may be or even larger. Similarly, conductor 24 in oxide 230_D The shortest distance between 2a and conductor 242b is the distance between conductor 242a and conductor in oxide 230_n. The shortest distance to body 242b may be approximately equal to, or greater than, this distance.

[0428] Furthermore, the shortest distance between conductor 242a and conductor 242b in oxide 230_D, and the acid The difference between the shortest distance between conductor 242a and conductor 242b in oxide 230_1 is, Conductors 242a and 242b in 230_1 (channel formation region 235_1) The shortest distance and the conductor 242 in oxide 230_2 (channel formation region 235_2) The difference between a and the shortest distance between them may be greater than the difference between a and the conductor 242b.

[0429] When multiple channel formation regions 235 are formed in parallel, channel formation located at the end Region 235 is prone to shape variations due to processing. Also, a part of the insulator 280, The stacked structure on the channel-forming region of oxide 230 is removed and an opening is provided, and the oxide 230 In the process of exposing a portion of the upper surface, the shape of the end of the area to be removed (also called an opening), or Due to variations in the distance between the oxide 230 and the edge of the opening, the exposure of the oxide 230 is affected. There may be variations in the surface area of ​​the top surface.

[0430] Therefore, as shown in Figures 28A and 28B, by providing transistor 200D If a shape defect occurs in the oxide 230_D of transistor 200D, or oxidation Even if a shape defect occurs in the opening on object 230_D, the area sandwiched between transistors 200D The shape of the oxide 230 formed in the region becomes homogeneous.

[0431] Therefore, by placing transistor 200D adjacent to transistor 200, multiple When a number of transistors 200 are provided, the characteristics of the multiple transistors 200 vary. This can reduce sticking.

[0432] Furthermore, in the semiconductor device shown in Figures 28A and 28B, transistor 200 is Each gate electrode has multiple channel-forming regions, as shown in Figures 28A and 28B. Transistor 200 obtains a large on-current by having multiple channel formation regions. This is possible. In addition, each channel-forming region is a structure covered with a gate electrode, that is, Because it has an s-channel structure, each channel formation region is large A suitable on-current can be obtained. Alternatively, in the channel width direction of transistor 200 , with the bottom surface of the insulator 222 as the reference, the conductor 260 and the oxide 23 The height of the bottom surface of the region that does not overlap with 0b is the boundary between the top surface of oxide 230b and insulator 250. Because it is lower than the surface height, a large on-current can be obtained in each channel formation region. It is possible.

[0433] Furthermore, other configurations may be determined by referring to the semiconductor device configurations shown in Figures 3A to 3D. can.

[0434] <Examples of semiconductor device applications> In the following sections, using Figures 29A and 29B, we will explain the above <Example of Semiconductor Device Configuration> and the above A transistor 2 according to one aspect of the present invention, which differs from the one shown in <Modification of Semiconductor Device>. An example of a semiconductor device having 00 and an aperture region 400 will be described. See Figure 29. In the semiconductor device shown in A and Figure 29B, the semiconductor device shown in <Example of semiconductor device configuration> Structures having the same function as the structures that constitute the configuration (see Figures 3A to 3D) are denoted by the same reference numeral. In this section, the constituent materials of transistor 200 are as follows: The materials described in detail in <Configuration Examples> and <Modified Examples of Semiconductor Devices> can be used.

[0435] Figures 29A and 29B show multiple transistors 200_1 to transistor 200_ The configuration in which n is enclosed and sealed by insulators 283 and 212 is shown. Note: Figure 2 In 9A and Figure 29B, transistors 200_1 to 200_n are, They appear to be aligned along the channel length, but this is not the only arrangement. Transition The transistors 200_1 through 200_n may be arranged in the channel width direction, They may be arranged in a matrix. Alternatively, they may be arranged without any regularity, depending on the design. It's fine if you do that.

[0436] As shown in Figure 29A, an aperture region 400 is placed between adjacent transistors 200. By performing a heat treatment after forming the aperture region 400 in the semiconductor device manufacturing process, the insulator The oxygen contained in 280, and the hydrogen bonded to that oxygen, are released to the outside through the opening region 400. It can be released into the atmosphere. Furthermore, hydrogen that combines with oxygen is released as water. Therefore, Unwanted oxygen and hydrogen contained in the edge material 280 can be reduced. Outside transistors 200_1 to 200_n, the insulator 283 and the insulating material are connected. A portion where the edge 212 makes contact (hereinafter sometimes referred to as the sealing portion 265) is formed. The sealing portion 265 surrounds a plurality of transistors 200_1 to 200_n. It is formed in this way. By using this structure, multiple transistors 200_1 to The transistor 200_n can be enclosed by the insulator 283 and the insulator 212. Therefore, it can be sealed. Multiple transistor groups, each enclosed by a stopper 265, will be provided on the substrate.

[0437] Also, a dicing line (scribe line, division line, or A cutting line may be provided. The above substrate is divided at the dicing line. Because it is disconnected, the group of transistors surrounded by the sealing portion 265 is extracted as a single chip. It will become that.

[0438] Furthermore, in Figure 29A, multiple transistors 200_1 to 200_n are connected. An example of surrounding with two sealing portions 265 has been shown, but it is not limited to this. Figure 29B shows As shown, multiple transistors 200_1 to 200_n are connected to multiple sealing parts It may also be configured to enclose it. In Figure 29B, multiple transistors 200_1 or to The structure is such that the 200_n is surrounded by the sealing portion 265a, and further surrounded by the outer sealing portion 265b. Yes, they are.

[0439] In this way, multiple transistors 200_1 to transistor 200_ are enclosed in multiple sealing portions. By creating a configuration that surrounds n, the area where insulator 283 and insulator 212 are in contact increases, so The adhesion between the edge body 283 and the insulator 212 can be further improved. This makes it more reliable. In fact, multiple transistors 200_1 through 200_n can be sealed. .

[0440] In this case, even if a dicing line is provided overlapping the sealing portion 265a or the sealing portion 265b Alternatively, a dicing line may be provided between the sealing portion 265a and the sealing portion 265b.

[0441] According to one aspect of the present invention, a semiconductor device with less variation in transistor characteristics is provided. This is possible. Alternatively, according to one aspect of the present invention, a reliable semiconductor device can be provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device having good electrical characteristics is provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device with a large on-current is provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor that can be miniaturized or highly integrated can be produced. An apparatus can be provided. Or, according to one aspect of the present invention, a low-power semiconductor device can be provided. We can provide this.

[0442] The configurations and methods described in this embodiment are not representative of other configurations, methods, etc. This can be used in appropriate combination with the configurations and methods shown in the embodiments and examples. It is possible.

[0443] (Embodiment 2) In this embodiment, one form of a semiconductor device will be described with reference to Figures 30 to 35.

[0444] [Storage device 1] Figure 30 shows an example of a semiconductor device (memory device) according to one aspect of the present invention. In this semiconductor device, transistor 200 is located above transistor 300, and a capacitive element 100 is located above transistors 300 and 200. As transistor 200, the transistor 200 described in the previous embodiment is used. It is possible.

[0445] Transistor 200 is a transistor in which a channel is formed in a semiconductor layer having an oxide semiconductor. It is a transistor. Transistor 200 is used in memory devices because it has a low off-current. This makes it possible to retain memory content for a long period of time. In other words, refresh Because it does not require any operation, or because the refresh operation is performed very infrequently, the memory Power consumption can be significantly reduced.

[0446] In the semiconductor device shown in Figure 30, the wiring 1001 is connected to the source and electrical source of transistor 300. The wiring 1002 is electrically connected to the drain of transistor 300. Furthermore, wiring 1003 is electrically connected to either the source or the drain of transistor 200. The wiring 1004 is then electrically connected to the first gate of transistor 200, and the wiring 1 006 is electrically connected to the second gate of transistor 200. And, The gate of transistor 300, and the other of the source and drain of transistor 200, The wiring 1005 is electrically connected to one of the electrodes of the capacitance element 100, and the wiring 1005 is connected to the electrode of the capacitance element 100. It is electrically connected to the other side.

[0447] Furthermore, the memory device shown in Figure 30 is arranged in a matrix, thereby creating a memory cell array. It can be configured.

[0448] <Transistor 300> The transistor 300 is provided on the substrate 311 and has a conductor 316 that functions as a gate. , an insulator 315 that functions as a gate insulator, and a semiconductor region 31 which is part of the substrate 311 3, and a low-resistance region 314a that functions as a source region or drain region, and low It has a resistive region 314b. Transistor 300 is either a p-channel or n-channel type. Any type is acceptable.

[0449] Here, the transistor 300 shown in Figure 30 is in the semiconductor region 313 where the channel is formed. A portion of the substrate 311 has a convex shape. In addition, the side and top surfaces of the semiconductor region 313 are made of an insulating material. The conductive material 316 is provided so as to cover the edge 315. Materials that adjust the work function may be used. Such a transistor 300 is on a semiconductor substrate. It is also called a FIN-type transistor because it utilizes a protruding part. Furthermore, it may have an insulator that functions as a mask for forming the protrusion. This example shows a case where a protrusion is formed by processing a part of a semiconductor substrate, but when processing an SOI substrate... A semiconductor film having a convex shape may be formed.

[0450] Note that the transistor 300 shown in Figure 30 is just one example, and its structure is not limited to that example. A suitable transistor should be used depending on the configuration and driving method.

[0451] <Capacitive element 100> The capacitive element 100 is located above the transistor 200. The capacitive element 100 is the first A conductor 110 that functions as an electrode, a conductor 120 that functions as a second electrode, and It has an insulator 130 that functions as a dielectric. Here, the insulator 130 is in the form described above. It is preferable to use an insulator that can be used as the insulator 286 shown in the diagram.

[0452] Furthermore, for example, the conductor 112 and the conductor 110 provided on the conductor 246 are formed simultaneously. This is possible. Furthermore, the conductor 112 is connected to the capacitive element 100, the transistor 200, and It functions as a plug or wire that electrically connects to transistor 300.

[0453] In Figure 30, the conductors 112 and 110 are shown as having a single-layer structure, but this configuration is not limited to this. It is not specified, and may be a laminated structure of two or more layers. For example, a conductor with barrier properties and a highly conductive material A conductor with barrier properties and a conductor with high conductivity are bonded to each other. A highly conductive material may be formed.

[0454] Furthermore, the insulator 130 may be, for example, silicon oxide, silicon oxide nitride, or silicon oxide nitride. Silicon nitride, aluminum oxide, aluminum oxide nitride, aluminum oxide nitride, nitrile Aluminum oxide, hafnium oxide, hafnium oxide nitride, hafnium oxide nitride, hafnium nitride It can be made using materials such as nium, and can be constructed in layers or as a single layer.

[0455] For example, the insulator 130 may contain a material with high dielectric strength, such as silicon oxynitride, and a high dielectric strength material. It is preferable to use a laminated structure with a high-k material. With this configuration, the capacity element Child 100 has a high dielectric constant (high-k) insulator, which ensures sufficient capacitance. By having an insulator with high dielectric strength, the dielectric strength is improved, and the electrostatic discharge of the capacitive element 100 is reduced. It can suppress damage.

[0456] Furthermore, as an insulator of high-dielectric constant (high-k) materials (materials with a high relative permittivity), Having gallium, hafnium oxide, zirconium oxide, aluminum and hafnium Oxides, aluminum and hafnium-containing oxides and nitrides, silicon and hafnium Oxides having silicon and hafnium, or silicon and ha Examples include nitrides containing humium.

[0457] On the other hand, materials with high dielectric strength (materials with low dielectric constant) include silicon oxide and nitrogen oxide. Silicon oxide, silicon nitride, silicon nitride, silicon oxide with added fluorine, carbon Silicon oxide with added carbon and nitrogen, silicon oxide with voids It may be made of concrete or resin.

[0458] <Wiring layer> Between each structure, there is a wiring layer containing interlayer membranes, wiring, and plugs. This is also possible. Furthermore, multiple wiring layers can be provided depending on the design. Here, the plug In the case of a conductor that functions as wiring, where multiple structures are grouped together and assigned the same code, There is a possibility of this occurring. Furthermore, in this specification, etc., the wiring and the plug that electrically connects to the wiring are integrated. It may also be an object. That is, when a part of the conductor functions as wiring, and the conductor Some parts may function as plugs.

[0459] For example, on transistor 300, there are insulators 320, 322, and an insulator as interlayer films. The edge body 324 and the insulator 326 are arranged in order in stacked layers. Also, the insulator 320, Insulators 322, 324, and 326 contain capacitive elements 100 or transients Conductors 328 and 330, etc., which are electrically connected to the sta 200, are embedded within. Furthermore, conductors 328 and 330 function as plugs or wiring.

[0460] Furthermore, the insulator, which functions as an interlayer film, acts as a planarizing film that covers the uneven shape beneath it. It may function. For example, the upper surface of the insulator 322 may be chemically and mechanically polished to improve flatness. The surface may be flattened by a flattening treatment such as the CMP method.

[0461] A wiring layer may be provided on the insulator 326 and the conductor 330. For example, as shown in Figure 30. Insulators 350, 352, and 354 are arranged in a stacked manner. Furthermore, a conductor 356 is formed on insulators 350, 352, and 354. Conductor 356 functions as a plug or wiring.

[0462] Similarly, insulators 210, 212, 214, and 216 are conductive Body 218 and the conductor (conductor 205) that constitutes the transistor 200 are embedded. It is present. Furthermore, the conductor 218 is electrically connected to the capacitive element 100 or the transistor 300. It functions as a connecting plug or wiring. Furthermore, the conductor 120 and the insulator An insulator 150 is provided above 130.

[0463] Here, similar to the insulator 241 shown in the above embodiment, a conductor 2 that functions as a plug An insulator 217 is provided in contact with the side surface of 18. The insulator 217 is in contact with the insulator 210, insulator 212, insulator 214, and insulator 216 are provided in contact with the inner wall of the opening formed therein. In other words, insulator 217 is connected to conductor 218, insulator 210, insulator 212, insulator It is provided between 214 and the insulator 216. Note that the conductor 205 is conductor 2 Since it can be formed in parallel with 18, the insulator 217 is in contact with the side surface of the conductor 205. It may also be formed.

[0464] Examples of insulators 217 include silicon nitride, aluminum oxide, or silicon nitride oxide. An insulator such as Ricon can be used. Insulator 217 is an insulator, insulator 210, insulator 212, Since it is provided in contact with the edge 214 and the insulator 222, the insulator 210 or the insulator 2 Impurities such as water or hydrogen from 16 etc. are mixed into the oxide 230 through the conductor 218. This can suppress hydrogen formation. In particular, silicon nitride has high blocking properties for hydrogen. Therefore, it is suitable. Also, the oxygen contained in the insulator 210 or insulator 216 is conductor 218 This can prevent it from being absorbed.

[0465] The insulator 217 can be formed in the same manner as the insulator 241. For example, PEA A silicon nitride film is deposited using the LD method, and the conductive material 356 is reached using anisotropic etching. You just need to form an opening.

[0466] Insulators that can be used as interlayer films include insulating oxides, nitrides, and acids. Examples include nitrides, nitride oxides, metal oxides, metal oxide nitrides, and metal nitride oxides.

[0467] For example, by using a material with a low dielectric constant for the insulator that functions as an interlayer film, wiring The parasitic capacitance that occurs between them can be reduced. Therefore, depending on the function of the insulator, the material You should choose this option.

[0468] For example, insulators 150, 210, 352, and 354 have a ratio It is preferable to have an insulator with a low dielectric constant. For example, the insulator may have fluorine added. Silicon oxide, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, It is preferable to have a porous silicon oxide or resin, or the insulator This involves adding silicon oxide, silicon oxide nitride, silicon oxide nitride, silicon nitride, and fluorine. Silicon oxide, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen It is preferable to have a laminated structure of silicon oxide having pores or cavities and a resin. Because silicon and silicon oxide-nitride are thermally stable, they can be combined with resins. This allows for a thermally stable laminated structure with a low dielectric constant. Examples of resins include: Polyester, polyolefin, polyamide (nylon, aramid, etc.), polyimide, Materials include polycarbonate or acrylic.

[0469] Furthermore, transistors using oxide semiconductors suppress the permeation of impurities such as hydrogen and oxygen. By surrounding the transistor with an insulator that has a controlling function, the electrical characteristics of the transistor are stabilized. Therefore, hydrogen, etc. can be present in insulators 214, 212, and 350, etc. An insulator that has the function of suppressing the permeation of impurities and oxygen should be used.

[0470] Examples of insulators that have the function of suppressing the permeation of impurities such as hydrogen and oxygen include, Boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, salt Element, argon, gallium, germanium, yttrium, zirconium, lanthanum, neo Insulators containing zym, hafnium, or tantalum may be used in single or multilayer configurations. Specifically, as an insulator that has the function of suppressing the permeation of impurities such as hydrogen and oxygen, Aluminum oxide, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide Umium, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, or tan oxide Metal oxides such as tar, silicon nitride, or silicon nitride can be used. .

[0471] Conductors that can be used in wiring and plugs include aluminum, chromium, copper, and silver. Gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanilla Dium, niobium, manganese, magnesium, zirconium, beryllium, indium, Materials containing one or more metallic elements selected from thenium and others can be used. Semiconductors with high electrical conductivity, such as polycrystalline silicon containing impurity elements like nitrates, Silicides such as nickel silicide may also be used.

[0472] For example, conductor 328, conductor 330, conductor 356, conductor 218, and conductor 1 12, etc., are metal materials, alloy materials, metal nitride materials, or formed from the above materials. Conductive materials such as metal oxide materials can be used in a single layer or in a laminated form. Heat resistance and It is preferable to use high-melting-point materials such as tungsten or molybdenum that can achieve both conductivity and electrical conductivity. Tungsten is preferable. Alternatively, a low-resistance conductive material such as aluminum or copper may be used. It is preferable to form it with a material. By using a low-resistance conductive material, the wiring resistance can be reduced. It is possible.

[0473] <Wiring or plugs in layers containing oxide semiconductors> Furthermore, when an oxide semiconductor is used for transistor 200, excess near the oxide semiconductor An insulator having an oxygen region may be provided. In that case, the insulator having the excess oxygen region A barrier-type insulator is provided between the insulator having the excess oxygen region and the conductor. It is preferable to provide one.

[0474] For example, in Figure 30, insulators 224 and 280 having excess oxygen, and conductor 2 It is preferable to provide an insulator 241 between 40 and 40. Insulator 241, insulator 222, insulator 2 82, and the insulator 283 are provided in contact with each other, so that the insulator 224 and the transient The STA200 can be constructed to be sealed with a barrier-type insulator.

[0475] In other words, by providing the insulator 241, the excess insulation of the insulators 224 and 280 is eliminated. This can suppress the absorption of oxygen by the conductor 240. Also, the insulator 241 By having this, the impurity hydrogen diffuses to the transistor 200 via the conductor 240. This can suppress the action.

[0476] Furthermore, the insulator 241 is designed to suppress the diffusion of impurities such as water or hydrogen, and oxygen. It is preferable to use an insulating material that has the function of [doing something]. For example, silicon nitride, silicon nitride oxide, It is preferable to use aluminum oxide or hafnium oxide. In particular, silica nitride N is preferred because it has high blocking properties for hydrogen. In addition, other options include, for example, magnesium oxide. Nesium, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, acid Metal oxides such as lanthanum oxide, neodymium oxide, or tantalum oxide can be used. ru.

[0477] Furthermore, as shown in the above embodiment, the transistor 200 is an insulator 212, an insulator The configuration may be sealed with insulators 282 and 283. By configuring it in this way, hydrogen contained in insulator 274, insulator 150, etc. enters insulator 280, etc. If it is mixed in, it can be reduced.

[0478] Here, the insulator 283 and insulator 282 have a conductor 240, insulator 214, and The conductor 218 penetrates the insulator 212, but as described above, the insulator 241 is connected to the conductor 2 It is provided in contact with 40, and the insulator 217 is provided in contact with the conductor 218. And, via conductors 240 and 218, insulators 212, 214, and 2 82 and the amount of hydrogen mixed inside the insulator 283 can be reduced. And, insulator 212, insulator 214, insulator 282, insulator 283, insulator 241, and The transistor 200 is sealed with insulator 217, and impurities such as hydrogen contained in insulator 274, etc. This can reduce the amount of contamination from the outside.

[0479] <Dicing line> In the following, by dividing a large-area substrate into semiconductor elements, multiple semiconductor devices are created. Dicing lines (scribe lines, division lines) are provided when extracting chips. This explains the cutting line (which may also be called the cutting line). For example, the method of division is... First, grooves (dicing lines) are formed in the substrate to divide the semiconductor elements, In some cases, the semiconductor device may be cut during grinding, resulting in its division into multiple semiconductor devices.

[0480] Here, for example, as shown in Figure 30, the region where the insulator 283 and the insulator 212 are in contact. It is preferable to design it so that it overlaps with the dicing line. In other words, multiple transistors Near the region that will become the dicing line, which is provided on the outer edge of the memory cell having 200 And, insulator 282, insulator 280, insulator 272, insulator 224, insulator 222, insulator Openings are provided in 216 and the insulator 214.

[0481] In other words, insulator 282, insulator 280, insulator 272, insulator 224, insulator 222, In the openings provided in the insulator 216 and the insulator 214, the insulator 212 and the insulator 28 3 is in contact with each other. For example, at this time, the insulator 212 and the insulator 283 are made of the same material and by the same method. They may be formed using the same material and method. Insulator 212 and insulator 283 may be formed using the same material and method. By providing this, adhesion can be improved. For example, silicon nitride is preferred. It seems so.

[0482] With this structure, insulators 212, 214, 282, and 283 , can enclose transistor 200. Insulator 212, insulator 214, insulator 2 82, and at least one of the insulators 283, have the function of suppressing the diffusion of oxygen, hydrogen, and water. Because it has, for each circuit region where the semiconductor element shown in this embodiment is formed, the substrate By dividing the substrate, even if it is processed into multiple chips, hydrogen or This prevents impurities such as water from contaminating the transistor 200 and diffusing into it.

[0483] Furthermore, this structure allows excess oxygen from the insulators 280 and 224 to diffuse to the outside. This can be prevented. Therefore, excess oxygen in insulator 280 and insulator 224 The acid is efficiently supplied to the oxide that forms the channel in transistor 200. This reduces oxygen vacancies in the oxide that form the channel in transistor 200. This allows the channel in transistor 200 to be formed in the oxide. This allows for the creation of an oxide semiconductor with a low defect level density and stable properties. In other words, This suppresses fluctuations in the electrical characteristics of transistor 200 and improves its reliability. ru.

[0484] In the memory device shown in Figure 30, the shape of the capacitive element 100 is planar, but in this actual The storage devices shown in the form of the implementation are not limited to these. For example, as shown in Figure 31. The shape of the capacitive element 100 may be cylindrical. Note that the memory device shown in Figure 31 is an absolute The configuration below the edge 150 is the same as that of the semiconductor device shown in Figure 30.

[0485] The capacitive element 100 shown in Figure 31 has an insulator 150 on top of the insulator 130 and on top of the insulator 150 The insulator 142 and the guides placed in the openings formed in the insulator 150 and the insulator 142 The electric body 115, the insulator 145 on the conductor 115 and the insulator 142, and on the insulator 145 It comprises a conductor 125 and an insulator 152 on the conductor 125 and the insulator 145. Then, the conductor 115 and the insulator 142 are placed in the openings formed in the insulator 150 and the insulator 14 5, and at least a portion of the conductor 125 are arranged.

[0486] The conductor 115 functions as the lower electrode of the capacitive element 100, and the conductor 125 functions as the lower electrode of the capacitive element 10 The insulator 145 functions as the upper electrode of 0 and as the dielectric of the capacitive element 100. The capacitive element 100 has openings in the insulators 150 and 142, not only on the bottom surface, On the side, the upper electrode and the lower electrode are arranged facing each other with a dielectric in between, The capacitance per unit area can be increased. Therefore, increasing the depth of the opening will increase the capacitance per unit area. This allows the capacitance of the capacitive element 100 to be increased. By increasing the capacitance per unit area, it is possible to miniaturize or highly integrate semiconductor devices. This can be used to advance it.

[0487] Insulator 152 may be any insulator that can be used for insulator 280. The edge 142 functions as an etching stopper when forming an opening in the insulator 150. Preferably, any insulator that can be used for the insulator 214 may be used.

[0488] The shape of the openings formed in the insulators 150 and 142, when viewed from above, is rectangular. It may be a polygon other than a quadrilateral, or a polygon with curved corners. It may be a shape, or it may be a circular shape including an ellipse. Here, in a top view, the opening It is preferable to have a large overlapping area between the port and transistor 200. This reduces the occupied area of ​​the semiconductor device having the capacitive element 100 and the transistor 200. It is possible.

[0489] The conductor 115 is positioned in contact with the openings formed in the insulator 142 and the insulator 150. The upper surface of the conductor 115 is preferably substantially the same as the upper surface of the insulator 142. The lower surface of the conductor 115 is in contact with the conductor 110 through an opening in the insulator 130. 5 is preferably formed using the ALD method or CVD method, for example, conductor 2 Any conductive material suitable for 05 should be used.

[0490] The insulator 145 is positioned to cover the conductor 115 and the insulator 142. For example, It is preferable to deposit the insulator 145 using the ALD method or CVD method. 45 is, for example, silicon oxide, silicon oxide nitride, silicon oxide nitride, silicon nitride, Zirconium oxide, aluminum oxide, aluminum oxide nitride, aluminum oxide nitride, Aluminum nitride, hafnium oxide, hafnium oxide nitride, hafnium oxide nitride, hafnium nitride A material such as humic acid can be used, and it can be provided in a laminated or single layer. For example, insulator 1 As shown in 45, the layers are stacked in the order of zirconium oxide, aluminum oxide, and zirconium oxide. An insulating film can be used.

[0491] Furthermore, the insulator 145 may be a material with high dielectric strength, such as silicon oxynitride, or a high dielectric strength material. It is preferable to use a high-k material. Alternatively, a material with high dielectric strength and high A laminated structure of high-k dielectric materials may also be used.

[0492] Furthermore, as an insulator of high-dielectric constant (high-k) materials (materials with a high relative permittivity), Having gallium, hafnium oxide, zirconium oxide, aluminum and hafnium Oxides, aluminum and hafnium-containing oxides and nitrides, silicon and hafnium Oxides having silicon and hafnium, oxidized nitrides having silicon and hafnium Examples include nitrides containing um. By using such high-k materials, an insulator 1 Even if the thickness of 45 is increased, sufficient capacitance of the capacitive element 100 can be secured. Insulator 145 By increasing the thickness, the leakage current between the conductor 115 and the conductor 125 is suppressed. It is possible.

[0493] On the other hand, materials with high dielectric strength include silicon oxide, silicon oxide nitride, and silicon oxide nitride. Silicon oxide, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, Examples include silico...

Claims

[Claim 1] A first insulator and The transistor on the first insulator, The second insulator on the transistor, The third insulator on the second insulator, The fourth insulator on the third insulator, Having an opening region, The aforementioned opening region is The above-mentioned second insulator, The third insulator on the second insulator, The fourth insulator on the third insulator, The third insulator has an opening that reaches the second insulator, The fourth insulator is a semiconductor device that is in contact with the upper surface of the second insulator inside the opening.

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