Semiconductor equipment

Abstract

To provide a semiconductor device with minimal variation in transistor characteristics. [Solution] An oxide semiconductor film, and a source electrode and a drain electrode on the oxide semiconductor film, An interlayer insulating film is arranged to cover the oxide semiconductor film, the source electrode, and the drain electrode, A first gate insulating film on an oxide semiconductor film, and a second gate insulating film on the first gate insulating film. It has a gate electrode on a second gate insulating film, and the interlayer insulating film is the source electrode and the drain An opening is formed superimposed in the region between the electrodes, and the first gate insulating film, the second gate The gate insulating film and the gate electrode are placed within the opening of the interlayer insulating film, and the first gate insulating film It has oxygen and aluminum, and the first gate insulating film is more than the second gate insulating film. It has regions where the film thickness is thin.

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, semiconductor device development has progressed, with LSIs, CPUs, and memory being the main components used. Yes. A CPU is a semiconductor integrated circuit (at least a transistor) that is separated from a semiconductor wafer. It is an assembly of semiconductor elements having a memory and a terminal, and having electrodes that serve as connection terminals.

[0005] Semiconductor circuits (IC chips) such as LSIs, CPUs, and memory are mounted on circuit boards, for example. It is mounted on a printed 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. The transistor is used in integrated circuits (ICs) or image display devices (simply It is widely applied in electronic devices such as display devices (also written as display devices). Suitable for transistors. Silicon-based semiconductor materials are widely known as usable semiconductor thin films, but other materials Oxide semiconductors are attracting attention as a result.

[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 Initiative] [Problems that the invention aims to solve]

[0010] One aspect of the present invention provides a semiconductor device with less variation in transistor characteristics. 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 reliable semiconductor device. Alternatively, one aspect of the present invention provides a reliable semiconductor device. One of the objectives of this invention is to provide a semiconductor with a large on-current. Alternatively, one aspect of the present invention is a semiconductor with a large on-current. One of the objectives is to provide a device. Alternatively, one aspect of the present invention relates to the field effect mobility One of the objectives is to provide a semiconductor device with a large frequency. Alternatively, one aspect of the present invention is to provide a semiconductor device with a large frequency. One of the objectives is to provide a semiconductor device with good wavenumber characteristics. Or, one aspect of the present invention. One of the challenges is to provide semiconductor devices that can be miniaturized or highly integrated. Alternatively, one aspect of the present invention aims to provide a low-power semiconductor device. Alternatively, one aspect of the present invention aims to provide a method for manufacturing the above-mentioned semiconductor device. ru.

[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 relates to an oxide semiconductor film, and a source electrode and drain on the oxide semiconductor film. An interlayer insulating film is arranged to cover the electrode, the oxide semiconductor film, the source electrode, and the drain electrode. Edge film, first gate insulating film on oxide semiconductor film, second gate insulating film on first gate insulating film The device comprises a gate insulating film and a gate electrode on a second gate insulating film, wherein the interlayer insulating film is the source electrode. An opening is formed superimposed in the region between the drain electrode and the first gate insulating film, the second The two gate insulating films and the gate electrode are located within the opening of the interlayer insulating film, and the first gate The gate insulating film has oxygen and aluminum, and the first gate insulating film is the second gate insulating film. This is a semiconductor device having a region where the film thickness is thinner than the edge film.

[0013] Furthermore, in the above, the first gate insulating film is the upper surface and side surface of the oxide semiconductor film, It is preferable that the side of the source electrode, the side of the drain electrode, and the side of the interlayer insulating film are in contact. stomach.

[0014] Furthermore, in the above, the second gate insulating film has oxygen and silicon. preferable.

[0015] Furthermore, in the above, a third gate insulating film is placed between the second gate insulating film and the gate electrode. Preferably, the third gate insulating film contains nitrogen and silicon.

[0016] Furthermore, in the above, a fourth gate between the second gate insulating film and the third gate insulating film It is preferable that the insulating film is present, and the fourth gate insulating film comprises oxygen and hafnium. stomach.

[0017] Furthermore, in the above, the interlayer insulating film, the first gate insulating film, the second gate insulating film, and the third The gate insulating film and the gate electrode have an insulating film, the insulating film being an interlayer insulating film, the first gate The gate insulating film, the second gate insulating film, the third gate insulating film, and each of the gate electrodes The insulating film, which is in contact with at least a portion of the upper surface, preferably contains oxygen and aluminum. It seems so.

[0018] Furthermore, in the above, the thickness of the first gate insulating film is 0.5 nm or more and 3.0 nm or less. It is preferable that it has a region.

[0019] Furthermore, in the above, the oxide semiconductor film is selected from In, Ga, or Zn. It is preferable to have one or more of these.

[0020] Another aspect of the present invention is a first step of forming an oxide semiconductor film, and an oxide semiconductor A second step involves forming a conductive film on the film, and a third step involves processing the oxide semiconductor film and the conductive film into island-like structures. Step 3, and a fourth step of forming an interlayer insulating film on the oxide semiconductor film and the conductive film, and layer A fifth step involves processing the interlayer insulating film and the conductive film to form an opening that reaches the oxide semiconductor film. To cover the opening, an aluminum oxide film is formed by the ALD method as the first gate insulating film. A sixth step involves forming a film, and then microwave processing the oxide semiconductor film via the first gate insulating film. The seventh step involves creating a region on the first gate insulating film that is thicker than the first gate insulating film. A method for manufacturing a semiconductor device, comprising: an eighth step of forming a second gate insulating film having That is the case.

[0021] Another aspect of the present invention is a first step of forming an oxide semiconductor film, and an oxide semiconductor A second step involves forming a conductive film on the film, and a third step involves processing the oxide semiconductor film and the conductive film into island-like structures. Step 3, and a fourth step of forming an interlayer insulating film on the oxide semiconductor film and the conductive film, and layer A fifth step involves processing the interlayer insulating film and the conductive film to form an opening that reaches the oxide semiconductor film. To cover the opening, an aluminum oxide film is formed by the ALD method as the first gate insulating film. A sixth step involves forming a film, and on top of the first gate insulating film, a region with a film thickness greater than the first gate insulating film is formed. A seventh step involves forming a second gate insulating film having a region, and through the first gate insulating film, A method for manufacturing a semiconductor device, comprising an eighth step of performing microwave processing on an oxide semiconductor film. That is the case.

[0022] Furthermore, in the above, the first gate insulating film is the upper surface and side surface of the oxide semiconductor film, It is preferable that the conductive film is in contact with the side surface of the interlayer insulating film.

[0023] Furthermore, in the above, the second gate insulating film is silicon oxide or silicon oxide nitride. It is preferable to have one or both of the following selected from among them.

[0024] Furthermore, in the above, the thickness of the first gate insulating film is 0.5 nm or more and 3.0 nm or less. It is preferable that it has a region.

[0025] Furthermore, in the above, the oxide semiconductor film is selected from In, Ga, or Zn. The film is deposited by a sputtering method using a target with one or more offsets. , is preferable. [Effects of the Invention]

[0026] 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 semiconductor device having good electrical 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 with a large on-current is provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device with high field-effect mobility can be made It can be provided. Alternatively, according to one aspect of the present invention, a semiconductor device with good frequency characteristics can be provided. This can provide the following: Alternatively, according to one aspect of the present invention, miniaturization or high integration is possible. A semiconductor device can be provided. Alternatively, according to one aspect of the present invention, a low-power semiconductor device can be provided. A conductive device can be provided. Alternatively, according to one aspect of the present invention, the semiconductor device can be manufactured. We can provide a manufacturing method.

[0027] 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]

[0028] [Figure 1] Figure 1A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 1B to 1D are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 2] Figures 2A and 2B are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 3] Figure 3A illustrates the classification of IGZO crystal structures. Figure 3B illustrates the XRD spectrum of a CAAC-IGZO film. Figure 3C illustrates the micro-electron diffraction pattern of a CAAC-IGZO film. [Figure 4] Figure 4A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 4B to 4D are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 5]Figure 5A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 5B to 5D are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 6] Figure 6A is a top view of a semiconductor device according to one embodiment of the present invention. Figures 6B to 6D are cross-sectional views of a semiconductor device according to one embodiment 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 19 is a top view illustrating a microwave processing apparatus according to one aspect of the present invention. [Figure 20] Figure 20 is a cross-sectional view illustrating a microwave apparatus according to one aspect of the present invention. [Figure 21] Figure 21 is a cross-sectional view illustrating a microwave processing apparatus according to one aspect of the present invention. [Figure 22] Figure 22 is a cross-sectional view illustrating a microwave processing apparatus according to one aspect of the present invention. [Figure 23] Figure 23A is a plan view of a semiconductor device according to one embodiment of the present invention. Figures 23B and 23C are cross-sectional views of a semiconductor device according to one embodiment of the present invention. [Figure 24] Figure 24 is a cross-sectional view showing the configuration of a storage device according to one aspect of the present invention. [Figure 25] Figure 25 is a cross-sectional view showing the configuration of a storage device according to one aspect of the present invention. [Figure 26] Figure 26 is a cross-sectional view of a semiconductor device according to one aspect of the present invention. [Figure 27] Figures 27A and 27B are cross-sectional views of a semiconductor device according to one aspect of the present invention. [Figure 28] Figure 28 is a cross-sectional view of a semiconductor device according to one aspect of the present invention. [Figure 29] Figure 29A is a block diagram showing an example of the configuration of a storage device according to one aspect of the present invention. Figure 29B is a perspective view showing an example of the configuration of a storage device according to one aspect of the present invention. [Figure 30] Figures 30A to 30H are circuit diagrams showing an example of the configuration of a storage device according to one aspect of the present invention. [Figure 31] Figures 31A and 31B are schematic diagrams of a semiconductor device according to one aspect of the present invention. [Figure 32] Figures 32A and 32B illustrate an example of an electronic component. [Figure 33] Figures 33A to 33E are schematic diagrams of a storage device according to one embodiment of the present invention. [Figure 34] Figures 34A to 34H show an electronic device according to one aspect of the present invention. [Figure 35] Figures 35A and 35B are graphs showing the measurement results of the sample according to this embodiment. [Figure 36] Figure 36 is a graph showing the measurement results of the sample according to this embodiment. [Figure 37] Figures 37A and 37B are cross-sectional STEM images of the sample according to this embodiment. [Figure 38] Figures 38A and 38B are cross-sectional STEM images of the sample according to this embodiment. [Figure 39] Figures 39A and 39B are cross-sectional STEM images of the sample according to this embodiment. [Figure 40] Figures 40A and 40B are graphs showing the results of reliability tests of the samples according to this embodiment. [Figure 41] Figures 41A to 41C are top views of the sample according to this embodiment. Figure 41D is a diagram illustrating the measurement position according to this embodiment. [Figure 42] Figures 42A and 42B are graphs showing the electrical characteristics of the sample according to this embodiment. [Figure 43] Figures 43A and 43B are graphs showing the electrical characteristics of the sample according to this embodiment. [Figure 44]Figures 44A and 44B are graphs showing the electrical characteristics of the sample according to this embodiment. [Figure 45] Figures 45A and 45B are graphs showing the electrical characteristics of the sample according to this embodiment. [Figure 46] Figures 46A and 46B are graphs showing the electrical characteristics of the sample according to this embodiment. [Figure 47] Figures 47A and 47B are graphs showing the electrical characteristics of the sample according to this embodiment. [Modes for carrying out the invention]

[0029] 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.

[0030] 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, layers or resist masks are removed through processes such as etching. While some figures may decrease without being shown in the diagram, this is sometimes omitted to facilitate understanding. Furthermore, in drawings, the same reference numeral is used for identical parts or parts having similar functions, but different numerals are used for different parts. It is used in common across different surfaces, and explanations of its repetition may be omitted. Also, similar functions may be indicated. In such cases, the hatch pattern may be the same, and no specific designation may be assigned.

[0031] Furthermore, the understanding of the invention is particularly important in top views (also called "plan views") or perspective views. For ease of understanding, descriptions of some components may be omitted. Also, some hidden lines, etc. The description may be omitted in some cases.

[0032] 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.

[0033] 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.

[0034] 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.)

[0035] 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.

[0036] Furthermore, the source and drain functions may differ when using transistors with different polarities, or The direction of the current may change during circuit operation, for example. Therefore, In this specification, the terms source and drain may be used interchangeably. There is.

[0037] 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.

[0038] 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.

[0039] 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. The effective channel width will be larger than the channel width shown above.

[0040] 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. An assumption is necessary. Therefore, if the shape of the semiconductor is not precisely known, the effective It is difficult to accurately measure channel width.

[0041] 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.

[0042] 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, the defect level density of a semiconductor may increase, or its crystallinity may decrease. Yes, there are. When the semiconductor is an oxide semiconductor, examples of impurities that alter the properties of the semiconductor include: For example, Group 1 elements, Group 2 elements, Group 13 elements, Group 14 elements, Group 15 elements, oxides, etc. Other components besides the main component of conductors include transition metals, such as hydrogen, lithium, sodium, and silicon. These include ions, boron, phosphorus, carbon, and nitrogen. Note that water can also function as an impurity. Furthermore, for example, the inclusion of impurities can cause oxygen vacancies (V) in oxide semiconductors. O :oxygen A vacancy (also called a vacancy) may form.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] (Embodiment 1) In this embodiment, Figures 1A to 23C illustrate a transistor according to one aspect of the present invention. An example of a semiconductor device having 200 and a method for manufacturing the same will be described.

[0049] <Example of semiconductor device configuration> The configuration of a semiconductor device having transistor 200 will be explained using Figure 1. Figure 1D is a top view and a cross-sectional view of a semiconductor device having transistor 200. Figure 1A Figure 1B to Figure 1D are cross-sections of the semiconductor device. This is a diagram. Here, Figure 1B is a cross-sectional view of the area shown by the dashed line A1-A2 in Figure 1A. This is also a cross-sectional view of transistor 200 in the channel length direction. Furthermore, Figure 1C is a cross-sectional view of Figure 1A. This is a cross-sectional view of the area indicated by the dashed line in 3-A4, showing the channel width direction of transistor 200. It is also a cross-sectional view. Figure 1D is a cross-sectional view of the area indicated by the dashed line A5-A6 in Figure 1A. Yes, it exists. Note that some elements have been omitted in the top view of Figure 1A for clarity.

[0050] 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, insulator 282 on insulator 280, insulator 283 on insulator 282, Insulator 274 on insulator 283, and insulator 28 on insulator 283 and insulator 274 It has 5, insulator 212, insulator 214, insulator 280, insulator 282, insulator 2 83, insulator 285, and insulator 274 function as interlayer films. Also, transistor Conductor 240 (conductor 240a, and conductor 240a) is electrically connected to 200 and functions as a plug. It has a conductor 240b). Furthermore, the side surface of the conductor 240, which functions as a plug, is in contact with an insulating material. Edge members 241 (insulators 241a and 241b) are provided. In addition, insulator 28 On 5 and on the conductor 240, there are connections to the conductor 240 that function as wiring. Conductors 246 (conductors 246a and conductors 246b) are provided. In addition, an insulator 2 83 is a part of the top surface of insulator 214, a side of insulator 216, a side of insulator 222, and an insulator It is in contact with the side surface of 280, and with the side and top surface of the insulator 282.

[0051] In contact with the inner wall of the opening of insulator 280, insulator 282, insulator 283, and insulator 285 An insulator 241a is provided, and a conductor 240a is provided in contact with the side surface of the insulator 241a. In addition, the openings of insulators 280, 282, 283, and 285 An insulator 241b is provided in contact with the inner wall of the insulator 241b, and a conductor 240 is provided in contact with the side surface of the insulator 241b. b is provided. The insulator 241 is provided so that the first insulator is in contact with the inner wall of the opening. Furthermore, a second insulator is provided on the inside. The first conductor is provided in contact with the side surface of the insulator 241, and the second conductor is further inside. The structure is designed to be such that the height of the upper surface of the conductor 240 and the weight of the conductor 246 are considered. The height of the upper surface of the insulator 285 in that region can be made to be approximately the same.

[0052] In addition, in transistor 200, the first insulator and the second insulator of insulator 241 The present invention illustrates a configuration in which two insulators are stacked, but is not limited thereto. For example, the insulator 241 may be provided as a single layer or as a laminated structure of three or more layers. In addition, in transistor 200, the first conductor and the conductor 240 Although a configuration in which a second conductive material is stacked is shown, the present invention is not limited thereto. For example, even if the conductor 240 is provided as a single layer or as a laminated structure of three or more layers Good. When a structure has a layered structure, ordinal numbers may be assigned to distinguish it based on the order of formation.

[0053] [Transistor 200] As shown in Figures 1A to 1D, 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 and 205b), on the insulator 216, and on the conductor 205 Insulator 222, insulator 224 on insulator 222, oxide 230a on insulator 224 , oxide 230b on oxide 230a, conductor 242a on oxide 230b, conductor Insulator 271a on 242a, conductor 242b on oxide 230b, and conductor 242b The upper insulator 271b, the insulator 252 on the oxide 230b, and the insulator 2 on the insulator 252 50, an insulator 254 on the insulator 250, and an oxide 230b located on the insulator 254 The conductor 260 (conductor 260a and conductor 260b) overlaps with a portion of the insulator 222 Insulator 224, oxide 230a, oxide 230b, conductor 242a, conductor 242b, It comprises an insulator 271a and an insulator 275 disposed on the insulator 271b. As shown in Figures 1B and 1C, the insulator 252 is on the upper surface of the insulator 222, and the insulator 2 24 side surfaces, oxide 230a side surface, oxide 230b side surface and top surface, conductor 242 Side, side of insulator 271, side of insulator 275, side of insulator 280, and insulator 2 It is in contact with the lower surface of 50. Also, the upper surface of the conductor 260 is the uppermost part of the insulator 254, and the insulator 25 The top of 0, the top of insulator 252, and the top surface of insulator 280 are roughly at the same height. They are arranged in the following order. Also, the insulator 282 is connected to the conductor 260, insulator 252, insulator 250, It is in contact with at least a portion of the upper surface of the insulator 254 and the insulator 280.

[0054] In the following, oxides 230a and 230b will be collectively referred to as oxide 230. There are cases where conductors 242a and conductors 242b are collectively referred to as conductor 242. There are also cases where insulators 271a and 271b are collectively referred to as insulator 271. ru.

[0055] The insulators 280 and 275 are provided with openings that reach the oxide 230b. An insulator 252, an insulator 250, an insulator 254, and a conductor 260 are arranged within the opening. It is also done. In addition, in the channel length direction of transistor 200, the insulator 271a, A conductor 260 is placed between the conductor 242a, the insulator 271b, and the conductor 242b. Insulators 252, 250, and 254 are provided. Insulator 254 is It has a region that contacts the side surface of the conductor 260 and a region that contacts the bottom surface of the conductor 260.

[0056] 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.

[0057] 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.

[0058] Conductor 260 functions as the first gate (also called the top gate) electrode, and conductor 205 functions as a second gate (also called a back gate) electrode. It is also an insulator. Insulators 252, 250 and 254 function as the first gate insulator, and insulator 222 and insulator 224 function as a second gate insulator. The body is sometimes called the gate insulating layer or gate insulating film. Also, the conductor 242a is It functions as either a source or a drain, and the conductor 242b is either a source or a drain. It functions as the other. Also, at least one of the regions of the oxide 230 that overlaps with the conductor 260. This region functions as a channel-forming region.

[0059] Here, Figure 2A shows an enlarged view of the vicinity of the channel formation region in Figure 1B. Oxide 230 When oxygen is supplied to b, a channel-shaped region is formed between the conductor 242a and the conductor 242b. A region is formed. Therefore, as shown in Figure 2A, oxide 230b is formed in transistor 2 The region 230bc that functions as a channel formation region, and so as to sandwich the region 230bc are provided with a region 230ba and a region 23 0bb that function as a source region or a drain region. At least a part of the region 230bc overlaps with the conductor 260 . In other words, the region 230bc is provided in the region between the conductor 242a and the conductor 242b . The region 230ba is provided so as to overlap with the conductor 242a, and the region 230 bb is provided so as to overlap with the conductor 242b.

[0060] The region 230bc that functions as a channel formation region has less oxygen deficiency or lower impurity concentration than the region 230ba and the region 230 bb, and thus is a high-resistance region with a low carrier concentration. Therefore, the region 230bc can be of i-type (intrinsic) or substantially i-type .

[0061] In addition, the region 230ba and the region 230 that function as a source region or a drain region bb have a large amount of oxygen deficiency and a high impurity concentration such as hydrogen, nitrogen, or a metal element. As a result, the carrier concentration in the region 230ba and the region 230bb increases and the resistance decreases . That is, the region 230ba and the region 230bb are n-type regions with a high carrier concentration and low resistance compared to the region 230bc .

[0062] Here, the carrier concentration of the region 230bc that functions as a channel formation region is preferably 1×10 18 cm -3 or less, more preferably 1×10 17 cm -3 or less, and most preferably 1×10 cm 16 or less. -3It is even more preferable that it be less than 1 × 10 13 cm -3 It is even more preferable that it be less than 1 × 10 12 cm -3 It is even preferable to be less than Furthermore, regarding the lower limit of the carrier concentration in region 230bc, which functions as a channel-forming region... There are no particular limitations, but for example, 1 x 10 -9 cm -3 It can be done this way.

[0063] Furthermore, between region 230bc and region 230ba or region 230bb, the carrier concentration However, the carrier concentrations in regions 230ba and 230bb are equivalent to or lower than those in regions 230bb. A region is formed with a carrier concentration equivalent to or higher than that of region 230bc. This is also acceptable. In other words, the region is region 230bc and region 230ba or region 230bb It functions as a junction region. This junction region has hydrogen concentrations in region 230ba and region 2 Equivalent to or lower than a hydrogen concentration of 30 bb, equivalent to a hydrogen concentration in the 230 bc region. Or it may be higher. Also, the junction region has an oxygen deficiency in region 230. Oxygen deficiency equivalent to or less than that in regions ba and 230bb, and in region 230bc This can be equivalent to, or even worse than, the oxygen deficiency in the body.

[0064] In Figure 2A, regions 230ba, 230bb, and 230bc are oxides. An example of formation on 230b is shown, but the present invention is not limited thereto. For example, even if each of the above regions is formed not only with oxide 230b but also with oxide 230a, stomach.

[0065] 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.

[0066] Transistor 200 includes an 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 .

[0067] 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.

[0068] 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. .

[0069] 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.

[0070] In this way, by placing oxide 230a below oxide 230b, oxide 230a The amount of impurities and excess amounts of oxide 230b from structures formed below This can suppress the diffusion of oxygen.

[0071] 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. This can be obtained.

[0072] 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.

[0073] CAAC-OS has a highly crystalline, dense structure, and is free from impurities and defects (for example) Oxygen deficiency (V O It is a metal oxide with few (etc.). In particular, after the formation of the metal oxide, gold Heat treatment at a temperature that does not cause polycrystalline formation of the group oxides (for example, between 400°C and 600°C). This allows CAAC-OS to have a more crystalline and dense structure. In this way, the density of CAAC-OS is increased, thereby reducing the impurities in the CAAC-OS. Alternatively, it can further reduce oxygen diffusion.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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].

[0078] 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.

[0079] 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 dividing H, hydrogen (H) Removed from region 230bc, oxygen deficiency (V O ) can be replenished with oxygen. In other words, In region 230bc, "V O H → H + V O The following reaction occurs, and water in region 230bc The elemental concentration can be reduced. Therefore, the oxygen deficiency in region 230bc, and V O H This can reduce the carrier concentration.

[0080] 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. Insulator 271 and insulator 230b, which are provided covering the conductor 242 This can be reduced by 80. This allows for reduction in region 230 during microwave processing. In ba and region 230bb, V O This reduces H and prevents the supply of excessive oxygen. This prevents a decrease in carrier concentration.

[0081] Furthermore, after the deposition of the insulating film that will become the insulator 252, or after the deposition of the insulating film that will become the insulator 250 It is preferable to perform microwave treatment in an oxygen-containing atmosphere. 2. Alternatively, by performing microwave treatment in an oxygen-containing atmosphere via an insulator 250, Oxygen can be efficiently injected into region 230bc. Also, the insulator 252 is conductor 2 By positioning it so as to be in contact with the side of 42 and the surface of region 230bc, region 230b This suppresses the injection of more oxygen than necessary into c, thereby suppressing oxidation of the side surface of the conductor 242. Furthermore, oxidation of the sides of the conductor 242 is suppressed when forming the insulating film that becomes the insulator 250. It is possible.

[0082] Furthermore, the oxygen injected into region 230bc consists of oxygen atoms, oxygen molecules, and oxygen radicals (O Radicals, also known as atoms or molecules with unpaired electrons, or ions, can take various forms. Yes. The oxygen injected into region 230bc is one or more of the above forms. It is sufficient if it is an oxygen radical, and is particularly preferable. Also, insulator 252 and insulation Since the film quality of body 250 can be improved, the reliability of transistor 200 is improved. .

[0083] 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 the n-type. This suppresses variations in the electrical characteristics of transistor 200, preventing variations in the electrical characteristics of transistor 200 within the substrate surface. This can be suppressed.

[0084] By adopting the above configuration, we can provide a semiconductor device with less variation in transistor characteristics. It can provide a reliable semiconductor device. This makes it possible to provide a semiconductor device with good electrical characteristics.

[0085] Also, as shown in FIG. 1C, in a cross-sectional view in the channel width direction of the transistor 200, a curved surface may be provided between the side surface and the upper surface of the oxide 230b. That is, the end of the side surface and the end of the upper surface may be curved (hereinafter, also referred to as round). .

[0086] The radius of curvature of the curved surface is greater than 0 nm and smaller than the film thickness of the oxide 230b in the region overlapping with the conductor 242, or smaller than half of the length of the region without the curved surface. This is preferable. Specifically, the radius of curvature of the curved surface is greater than 0 nm and 20 nm or less. Preferably, it is 1 nm or more and 15 nm or less, and more preferably 2 nm or more and 10 nm or less. By adopting such a shape, the covering properties of the insulator 252, the insulator 250, the insulator 254, and the conductor 260 on the oxide 230b can be enhanced. . The oxide 230 preferably has a laminated structure of a plurality of oxide layers with different chemical compositions.

[0087] Specifically, in the metal oxide used for the oxide 230a, the atomic ratio of the element M to the metal element which is the main component is preferably larger than the atomic ratio of the element M to the metal element which is the main component in the metal oxide used for the oxide 230b. Also, in the metal oxide used for the oxide 230a, the atomic ratio of the element M to In is preferably larger than the atomic ratio of the element M to In in the metal oxide used for the oxide 230b. Further, in the metal oxide used for the oxide 230b, the atomic ratio of In to the element M is preferably larger than the atomic ratio of In to the element M in the metal oxide used for the oxide 230a. . In the metal oxide used for the oxide 230a, the atomic ratio of the element M to the metal element which is the main component is preferably larger than the atomic ratio of the element M to the metal element which is the main component in the metal oxide used for the oxide 230b. Also, in the metal oxide used for the oxide 230a, the atomic ratio of the element M to In is preferably larger than the atomic ratio of the element M to In in the metal oxide used for the oxide 230b. Further, in the metal oxide used for the oxide 230b, the atomic ratio of In to the element M is preferably larger than the atomic ratio of In to the element M in the metal oxide used for the oxide 230a. In the metal oxide used for the oxide 230b, the atomic ratio of In to the element M is preferably larger than the atomic ratio of In to the element M in the metal oxide used for the oxide 230a. This is preferable.

[0088] Furthermore, oxide 230b is preferably a crystalline oxide such as CAAC-OS. It is difficult. Crystalline oxides such as CAAC-OS contain impurities and defects (oxygen deficiencies). It has a dense structure with few particles and high crystallinity. Therefore, the source electrode or drain This makes it possible to suppress the abstraction of oxygen from oxide 230b by the in electrode. Furthermore, even when heat treatment is performed, the extraction of oxygen from oxide 230b can be reduced. Transistor 200 is designed to withstand high temperatures (so-called thermal budget) during the manufacturing process. It is stable.

[0089] 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.

[0090] 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 defect level density can be formed. For example, oxide 2 If 30b is In-M-Zn oxide, then oxide 230a is In-M-Zn oxide, Even when using M-Zn oxide, oxide of element M, In-Zn oxide, indium oxide, etc. good.

[0091] Specifically, for oxide 230a, In:M:Zn = 1:3:4 [atomic ratio] or This refers to the composition in its vicinity, or In:M:Zn=1:1:0.5 [atomic ratio] or its vicinity. A metal oxide with a similar composition can be used. Also, as oxide 230b, In:M:Zn = A composition of 1:1:1 [atomic ratio] or close to it, or In:M:Zn=4:2:3 [ A metal oxide with an atomic ratio of [amount] or a composition close to it should be used. Note that "composition close to" means , including a range of ±30% of the desired atomic ratio. Also, gallium is used as element M. It is preferable.

[0092] Furthermore, when depositing metal oxides by sputtering, the above atomic ratio is used for the deposition of the film. Not limited to the atomic ratio of the metal oxides, the sputtering target used for depositing metal oxide films The atomic ratio of the set may also be acceptable.

[0093] Furthermore, as shown in Figure 1C and other figures, aluminum oxide is in contact with the top and side surfaces of oxide 230. By providing an insulator 252 formed of nium, the oxide 230 and the insulator 2 In some cases, indium contained in oxide 230 may be unevenly distributed at and near the interface of 52. As a result, the vicinity of the surface of oxide 230 has an atomic ratio close to that of indium oxide, or I The atomic ratio is close to that of n-Zn oxide. In this way, oxide 230, especially oxide 230b As the atomic ratio of indium near the surface increases, the field effect transfer of transistor 200 It can improve mobility.

[0094] By configuring oxide 230a and oxide 230b as described above, oxide 230a and acid The defect level density at the interface with compound 230b can be reduced. Therefore, the interface dispersion The influence of disturbances on carrier conduction is reduced, and transistor 200 has a large on current. Higher frequency characteristics can be obtained.

[0095] Insulators 212, Insulators 214, Insulator 271, Insulator 275, Insulator 282, Insulator 2 At least one of 83 and Insulator 285 suppresses the diffusion of impurities such as water and hydrogen from the substrate side or from above the transistor 200 into the transistor 200 and preferably functions as a barrier insulating film. Therefore, at least one of Insulators 212, Insulators 214, Insulator 271, Insulator 275, Insulator 282, Insulator 283, and Insulator 285 preferably uses an insulating material having a function of suppressing the diffusion of impurity atoms such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (such as N2O, NO, NO2, etc.), and copper atoms (it is difficult for the above impurities to permeate). Or, it is preferable to use an insulating material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.) (it is difficult for the above oxygen to permeate). Note that in this specification, a barrier insulating film refers to an insulating film having barrier properties. In this specification, barrier properties refer to a function of suppressing the diffusion of the corresponding substance (also referred to as low permeability). Or, it refers to a function of capturing and fixing the corresponding substance (also referred to as gettering). As Insulators 212, Insulators 214, Insulator 271, Insulator 275, Insulator 282, Insulator 283, and Insulator 285, it is preferable to use an insulator having a function of suppressing the diffusion of impurities such as water and hydrogen and oxygen. For example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride can be used. For example, Insulators 212, Insulators 2

[0096]

[0097] Insulators 212, Insulators 214, Insulator 271, Insulator 275, Insulator 282, Insulator 2 83, and Insulator 285 preferably use an insulator having a function of suppressing the diffusion of impurities such as water, hydrogen, and oxygen. For example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride can be used. For example, Insulators 212, Insulators 2 ​​​​​​​​​​​​For material 75 and the insulator 283, silicon nitride or similar material with higher hydrogen barrier properties is used. It is preferable. Also, for example, insulator 214, insulator 271, insulator 282, and As the edge material 285, aluminum oxide, which has high hydrogen capture and hydrogen fixation capabilities, It is preferable to use magnesium oxide or the like. This removes impurities such as water and hydrogen. The insulators 212 and 214 diffuse from the substrate side to the transistor 200 side. This can suppress the formation of impurities such as water and hydrogen outside the insulator 285. This suppresses diffusion from the interlayer insulating film and other materials arranged in the transistor 200 to the transistor 200 side. This can be done. Alternatively, oxygen contained in insulator 224, etc., insulator 212, and insulator Diffusion to the substrate side via 214 can be suppressed. Alternatively, the insulator 280 can be used. The oxygen contained in it diffuses upward from the transistor 200 via the insulator 282, etc. This can suppress the generation of impurities such as water and hydrogen. , and insulators 212, 214, and 271 which have the function of suppressing the diffusion of oxygen The structure is surrounded by insulators 275, 282, 283, and 285. It is preferable to do so.

[0098] Next, insulator 212, insulator 214, insulator 271, insulator 275, insulator 282, By using oxides having an amorphous structure as insulators 283 and 285, This is preferable. For example, AlO x (x is any number greater than 0), or MgO y (y is 0) It is preferable to use metal oxides such as (any number greater than) In metal oxides having a structure, oxygen atoms have dangling bonds, and the dangling Ring bonds may have the property of capturing or fixing hydrogen. Such amorphous materials A metal oxide having a sphagnum structure is used as a component of the transistor 200, or By placing it around the transistor 200, hydrogen contained in the transistor 200, or the transistor Transistor 200 can capture or fix hydrogen present around it. It is preferable to capture or fix hydrogen contained in the channel-forming region of STA200. A metal oxide having a morphous structure is used as a component of transistor 200, By placing it around transistor 200, it provides good characteristics and reliable transistor Sta200 and semiconductor devices can be manufactured.

[0099] Also, insulators 212, 214, 271, 275, 282, The edge body 283 and the insulator 285 are preferably amorphous, but in part A region with a polycrystalline structure may be formed. Also, insulator 212, insulator 214, insulator Insulators 271, 275, 282, 283, and 285 are amorphous It may also be a multilayer structure in which layers of a crystalline structure and layers of a polycrystalline structure are stacked. For example, A layered structure in which a polycrystalline layer is formed on top of a morphous layer is also acceptable.

[0100] Insulator 212, Insulator 214, Insulator 271, Insulator 275, Insulator 282, Insulator 2 The deposition of film 83 and the insulator 285 can be carried out, for example, by sputtering. The puttering method does not require the use of hydrogen-containing molecules in the film-forming gas, so insulating materials 212, Edge 214, insulator 271, insulator 275, insulator 282, insulator 283, and insulator The hydrogen concentration can be reduced by 285. Note that the film deposition method is not limited to sputtering. It is not something that is grown by chemical vapor deposition (CVD). Molecular beam epitaxy (MBE) method Taxy method, Pulsed Laser Deposition (PLD) ion) method, Atomic Layer Deposition (ALD) Laws and other relevant laws may be used as appropriate.

[0101] Furthermore, it is preferable to lower the resistivity of insulators 212, 275, and 283. There are cases where this is difficult. For example, the resistivity of insulators 212, 275, and 283. Approximately 1 × 10 13 By setting it to Ωcm, processing using plasma, etc. in semiconductor device manufacturing processes. In this, insulator 212, insulator 275, and insulator 283 are conductor 205, conductor A field in which the charge up of conductor 242, conductor 260, or conductor 246 can be mitigated. There is a match. The resistivity of insulators 212, 275, and 283 is preferably, 1 x 10 10 Ωcm or more, 1 × 10 15 The density should be less than or equal to Ωcm.

[0102] Furthermore, insulators 216, 274, 280, and 285 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 285. Silicon oxide with added carbon, silicon oxide with added carbon and nitrogen Cone, porous silicon oxide, or other suitable materials can be used as appropriate.

[0103] 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. Furthermore, a portion of the conductor 205 may be embedded in the insulator 214.

[0104] Conductor 205 has conductor 205a and conductor 205b. Conductor 205a is , provided in contact with the bottom surface and side wall of the opening. Conductor 205b is provided in contact with conductor 205a It is provided so as to be embedded in the formed recess. Here, the height of the upper surface of the conductor 205b This roughly coincides with the height of the top surface of the conductor 205a and the height of the top surface of the insulator 216.

[0105] Here, the conductor 205a consists of hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and oxidation. It has the function of suppressing the diffusion of impurities such as nitrogen molecules (N2O, NO, NO2, etc.) and copper atoms. It is preferable to use a conductive material. Alternatively, oxygen (for example, oxygen atoms, oxygen molecules) It is preferable to use a conductive material that has the function of suppressing the diffusion of at least one of the following.

[0106] By using a conductive material that has the function of reducing hydrogen diffusion in the conductor 205a, Impurities such as hydrogen contained in the conductor 205b are transferred to the oxide 23 via the insulator 224, etc. It can prevent diffusion to 0. In addition, the conductor 205a has a mechanism that suppresses the diffusion of oxygen. By using a conductive material with certain properties, the conductor 205b oxidizes and its conductivity decreases. This can be suppressed. Conductive materials that have the function of suppressing oxygen diffusion include: For example, titanium, titanium nitride, tantalum, tantalum nitride, ruthenium, ruthenium oxide It is preferable to use such materials. Therefore, as the conductor 205a, the above conductive material is used as a single It can be in layers or stacked. For example, titanium nitride can be used for the conductor 205a.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] Furthermore, as shown in Figure 1A, 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 1C 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.

[0111] 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.

[0112] Furthermore, as shown in Figure 1C, 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.

[0113] In transistor 200, the conductor 205 consists of conductor 205a and conductor 20 Although the present invention describes a configuration in which 5b is stacked, it is not limited to this. For example, Alternatively, the conductor 205 may be provided as a single layer or as a laminated structure of three or more layers.

[0114] Insulators 222 and 224 function as gate insulators.

[0115] 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.

[0116] 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 from the peripheral area of ​​the transistor 200. It functions as a layer that suppresses the diffusion of impurities such as hydrogen into the oxide 230. Therefore, insulator 2 By providing 22, the diffusion of impurities such as hydrogen into the inside of transistor 200 is suppressed. This can control and suppress the generation of oxygen vacancies in the oxide 230. Also, the conductor 205 This suppresses the reaction of the insulator 224 and oxide 230 with oxygen. ru.

[0117] 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.

[0118] Furthermore, the insulator 222 may be, for example, aluminum oxide, hafnium oxide, tantalum oxide, Insulators containing so-called high-k materials such as zirconium oxide are used in single-layer or multi-layer configurations. It may be. As transistors become smaller and more integrated, the gate insulator will become thinner. Furthermore, problems such as leakage current may occur. By using high-k material, the gate during transistor operation can be maintained while preserving the physical film thickness. This makes it possible to reduce the potential. Also, lead zirconate titanate (PZT) is used as the insulator 222. , such as strontium titanate (SrTiO3), (Ba,Sr)TiO3 (BST), etc. In some cases, materials with a high dielectric constant can be used.

[0119] The insulator 224 in contact with the oxide 230 is, for example, silicon oxide, silicon oxide nitride, etc. Use it as appropriate.

[0120] 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. 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 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 ) Furthermore, the heat treatment may be carried out under reduced pressure. Alternatively, the heat treatment may be carried out under nitrogen gas or After heat treatment in an active gas atmosphere, an oxidizing gas is added at 10 pJ to replenish the desorbed oxygen. The procedure may be carried out in an atmosphere containing 1% or more of the substance, or 10% or more of the substance. Alternatively, an oxidizing gas may be used. After heat treatment in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more, then continuously The heat treatment may be carried out in a nitrogen gas or inert gas atmosphere.

[0121] 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.

[0122] 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 275 is in contact with the side surface of the insulator 224 and the top surface of the insulator 222. .

[0123] Conductors 242a and 242b are provided in contact with the upper surface of oxide 230b. Conductors 242a and 242b are the source electrodes of transistor 200, respectively. It functions as a drain electrode.

[0124] 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.

[0125] 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 has 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.

[0126] 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 making the conductor 242 in which the curved surface is not formed, as shown in Figure 1D This allows for an increase in the cross-sectional area of ​​the conductor 242 in the channel width direction. This increases the conductivity of conductor 242 and increases the on-current of transistor 200. It is possible.

[0127] 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. The insulator 271 is at least against oxygen It is preferable that the insulator 271 functions as a barrier insulating film. Therefore, the insulator 271 is oxygen It is preferable that the insulator has a function to suppress diffusion. For example, the insulator 271 is better than the insulator 280. It is preferable that the insulator 271 also has the function of suppressing oxygen diffusion. Alternatively, a silicon-containing nitride such as silicon nitride may be used. Also, the insulator 271 is water It is preferable that it has the function of capturing impurities such as elements. In that case, as the insulator 271 This refers to metal oxides having an amorphous structure, such as aluminum oxide or magnesium oxide. An insulator such as sium can be used. In particular, as insulator 271, an amorphous structure is used. By using aluminum oxide or amorphous aluminum oxide, This is preferable because it can effectively capture or fix hydrogen. This allows for the fabrication of a highly reliable transistor 200 and a semiconductor device. .

[0128] Insulator 275 consists of insulator 224, oxide 230a, oxide 230b, conductor 242, and It is provided so as to cover the insulator 271. The insulator 275 is used to capture hydrogen and hydrogen It is preferable that the insulator 275 has the function of fixing. In that case, the insulator 275 is silicon nitride. or an amorphous metal oxide, for example, aluminum oxide or oxide It is preferable to include an insulator such as magnesium. Also, for example, as insulator 275, A laminated film of aluminum oxide and silicon nitride on the aluminum oxide may also be used.

[0129] By providing the insulators 271 and 275 described above, a barrier property against oxygen is achieved. The conductor 242 can be wrapped in an insulator having the following properties: 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.

[0130] Insulator 252 functions as part of the gate insulator. Insulator 252 is oxygen-based It is preferable to use a barrier insulating film. As the insulator 252, the insulator 28 described above is preferable. Any insulator that can be used in 2 is acceptable. As insulator 252, aluminum and An insulator containing an oxide of one or both of hafnium may be used. , aluminum oxide, hafnium oxide, aluminum and hafnium oxide ( Hafnium aluminate), oxides containing hafnium and silicon (hafnium silicate) (T) etc. can be used. In this embodiment, as the insulator 252, aluminum oxide Aluminum is used. In this case, the insulator 252 has at least oxygen and aluminum. It becomes an insulator. In addition, the insulator 252 may have a laminated structure, for example, hafnium oxide. This allows for a layered structure of aluminum oxide on the hafnium oxide.

[0131] As shown in Figure 1C, the insulator 252 has the top and side surfaces of oxide 230b and oxide 23 It is provided in contact with the side surface of 0a, the side surface of the insulator 224, and the upper surface of the insulator 222. and the region of oxide 230a, oxide 230b, and insulator 224 that overlaps with the conductor 260 In the cross-section in the channel width direction, it is covered with an insulator 252. This allows for heat treatment When such processes are performed, oxygen is removed from oxides 230a and 230b, and oxygen is removed from them. It can be blocked by the insulator 252 which has barrier properties. Therefore, oxide 23 Oxygen deficiency in 0a and oxide 230b (V O This can reduce the formation of ). This results in an oxygen deficiency (V) being formed in region 230bc. O ), and V O Reduce H This allows for improved electrical characteristics and reliability of transistor 200. It is possible.

[0132] Conversely, even if the insulator 280 and insulator 250 contain an excessive amount of oxygen... The objective is to suppress the excessive supply of oxygen to oxides 230a and 230b. Therefore, regions 230ba and 230bb can pass through region 230bc. Excessive oxidation causes a decrease in the on-current of transistor 200 or a decrease in field-effect mobility. It can suppress rubbing.

[0133] Also, as shown in Figure 1B, the insulator 252 is composed of the conductor 242, the insulator 271, and the insulator 2 75 and the insulator 280 are provided in contact with each of their sides. Therefore, the conductor 242 This reduces oxidation of the side surface and the formation of an oxide film on that side surface. This prevents a decrease in the on-current of transistor 200 or a decrease in the field-effect mobility. It can be controlled.

[0134] Furthermore, the insulator 252 is in harmony with the insulators 254, 250, and 260. It is necessary to provide it in an opening formed in the insulator 280 or the like. Miniaturization of transistor 200 In achieving this, it is preferable that the film thickness of the insulator 252 be thin. 0.1 nm to 5.0 nm, preferably 0.5 nm to 3.0 nm, more preferably The wavelength shall be between 1.0 nm and 3.0 nm. In this case, the insulator 252 shall be at least partially In this case, it is sufficient to have a region with the above-mentioned film thickness. Also, the film thickness of the insulator 252 is It is preferable that the thickness of the edge 250 is thinner than the thickness of the edge 250. In this case, the insulator 252 is at least partially In this case, it is sufficient to have a region where the film thickness is thinner than that of the insulator 250.

[0135] To deposit the insulator 252 with a thin film thickness as described above, the ALD method should be used. This is preferable. The ALD method carries out the reaction of the precursor and reactant using only thermal energy. Thermal ALD (Advanced Laser Deposition) method, PE using plasma-excited reactant Examples include the ALD (Plasma Enhanced ALD) method. In the PEALD method, Using plasma allows for film deposition at lower temperatures, which can be advantageous in some cases.

[0136] The ALD method utilizes the self-regulating properties of atoms to deposit atoms layer by layer. Because it can deposit extremely thin films, it can deposit films on structures with high aspect ratios, and eliminates pinholes, etc. It enables film formation with fewer defects, film formation with excellent coverage, and film formation at low temperatures, among other benefits. There is an effect. Therefore, the insulator 252 is covered with the side surface of the opening formed in the insulator 280, etc. It allows for good film formation with the thin film thickness described above.

[0137] Furthermore, some precursors used in the ALD method contain carbon, etc. Therefore, ALD Films formed by this method contain fewer impurities such as carbon compared to films formed by other film formation methods. It may contain a large amount of [unclear]. Note that the quantitative determination of impurities is performed by secondary ion mass spectrometry (SIMS:Se Condary ion mass spectrometry, or X-ray photoelectron spectrometry Optical method (XPS:X-ray Photoelectron Spectroscopy) This can be done using [a specific method / tool].

[0138] Insulator 250 functions as part of the gate insulator. Insulator 250 is connected to insulator 252 It is preferable to place it in contact with the upper surface. The insulator 250 is silicon oxide, silicon oxidnitride Cone, silicon nitride oxide, silicon nitride, fluorine-added silicon oxide, carbon-added Silicon oxide, silicon oxide with added carbon and nitrogen, and silicon oxide with voids. These can be used. In particular, silicon oxide and silicon oxide nitride are stable to heat. Therefore, it is preferable. In this case, the insulator 250 has at least oxygen and silicon. It becomes an insulator.

[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 have a wavelength of 0.5 nm or more and 15.0 nm or less. In this case, The insulator 250 only needs to have a region with the above-described film thickness in at least a portion of it. .

[0140] Figures 1A to 1D show a configuration in which the insulator 250 is a single layer, but the present invention This is not limited to this, and a laminated structure of two or more layers is also possible. For example, as shown in Figure 2B, The body 250 has a two-layer laminated structure consisting of an insulator 250a and an insulator 250b on top of the insulator 250a. You may do so.

[0141] As shown in Figure 2B, when the insulator 250 has a two-layer laminated structure, the lower insulator 250 a is formed using an insulator that is permeable to oxygen, and the upper insulator 250b is for the diffusion of oxygen. It is preferable to form it using an insulator that has the function of suppressing [something]. This suppresses the diffusion of oxygen contained in the insulator 250a into the conductor 260. Yes, it is possible. In other words, it is possible to suppress the decrease in the amount of oxygen supplied to oxide 230. Also, This can suppress the oxidation of the conductor 260 by oxygen contained in the insulator 250a. The insulator 250a is provided using a material that can be used for the insulator 250 described above. Insulator 250b is an insulating material containing an oxide of either or both aluminum and hafnium. It is good to use a body. As the insulator, aluminum oxide, hafnium oxide, aluminum Oxides containing hafnium and hafnium (hafnium aluminate), hafnium and silica An oxide containing ions (hafnium silicate), etc., can be used. Hafnium oxide is used as the insulator 250b. In this case, the amount of insulator 250b is small. At most, it becomes an insulator containing oxygen and hafnium. Also, the film thickness of insulator 250b is 0.5 nm or more, 5.0 nm or less, preferably 1.0 nm or more, 5.0 nm or less, more preferably The minimum size is 1.0 nm or more and 3.0 nm or less. In this case, the amount of insulator 250b is small. At the very least, it is sufficient if a portion of the film thickness is as described above.

[0142] Furthermore, when silicon oxide or silicon oxide-nitride is used for the insulator 250a, Body 250b may be an insulating material, which is a high-k material with a high dielectric constant. The insulator has a laminated structure of insulator 250a and insulator 250b, making it safe against heat. A laminated structure with constant dielectric constant and high relative permittivity can be achieved. Therefore, the physical properties of the gate insulator This makes it possible to reduce the gate potential applied during transistor operation while maintaining the film thickness. Furthermore, it becomes possible to thin the equivalent oxide film thickness (EOT) of the insulator that functions as a gate insulator. Therefore, the dielectric strength of the insulator 250 can be increased.

[0143] Insulator 254 functions as part of the gate insulator. Insulator 254 is used for hydrogen It is preferable to use a barrier insulating film. This allows the hydrogen contained in the conductor 260 to be absorbed. This prevents impurities such as these from diffusing into the insulator 250 and oxide 230b. As for the insulator 254, any insulator that can be used for the insulator 283 described above may be used. For example, silicon nitride deposited by the PEALD method can be used as the insulator 254. In this case, the insulator 254 is an insulator having at least nitrogen and silicon.

[0144] Furthermore, the insulator 254 may also have barrier properties against oxygen. This can suppress the diffusion of oxygen contained in the edge material 250 into the conductor 260.

[0145] Furthermore, the insulator 254 is in harmony with the insulators 252, 250, and 260. It is necessary to provide it in an opening formed in the insulator 280 or the like. Miniaturization of transistor 200 In achieving this, it is preferable that the film thickness of the insulator 254 be thin. 0.1 nm to 5.0 nm, preferably 0.5 nm to 3.0 nm, more preferably The wavelength shall be between 1.0 nm and 3.0 nm. In this case, the insulator 254 shall be at least partially In this case, it is sufficient to have a region with the above-mentioned film thickness. Also, the film thickness of the insulator 254 is It is preferable that the thickness of the edge 250 is thinner than the thickness of the edge 250. In this case, the insulator 254 is at least partially In this case, it is sufficient to have a region where the film thickness is thinner than that of the insulator 250.

[0146] 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 1B and 1C, the conductor 260 The upper surface of the conductor is roughly the same as the upper surface of the insulator 250. Note that in Figures 1B and 1C, Although the conductive body 260 is shown as a two-layer structure of conductive material 260a and conductive material 260b, a single-layer structure is also shown. It can be a simple structure, or a laminated structure of three or more layers.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] Furthermore, as shown in Figure 1C, in the channel width direction of transistor 200, 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.

[0152] The insulator 280 is provided on the insulator 275, 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 occurring 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] It is preferable that the concentration of impurities such as water and hydrogen in the insulator 280 is reduced. The insulator 280 contains silicon oxides such as silicon oxide and silicon oxide nitride as appropriate. Use it.

[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. In this case, the insulator 282 is The insulator contains at least oxygen and aluminum. Insulator 212 and Insulator 28 Within the region enclosed by 3, it has the function of capturing impurities such as hydrogen while in contact with the insulator 280. Furthermore, by providing an 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, the insulator 282 and By using aluminum oxide with an amorphous structure, hydrogen can be more effectively extracted. It is preferable because it can be captured or fixed. This gives it good properties and reliability. High-performance transistors 200 and semiconductor devices can be fabricated.

[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 can be increased. A silicon nitride film with high properties can be formed. Also, as the insulator 283, sputtering On top of the silicon nitride film deposited by the poring method, further film deposition is performed using the PEALD method or the CVD method. The silicon nitride may be laminated.

[0157] 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.

[0158] Furthermore, when the conductor 240 is made into a laminated structure, the insulator 285, insulator 283, insulator 28 2. A first conductor located near insulators 280, 275, and 271. For this purpose, it is preferable to use a conductive material that has the function of suppressing the permeation of impurities such as water and hydrogen. For example, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium oxide It is preferable to use materials such as nium. Furthermore, it should have a function to suppress the permeation of impurities such as water and hydrogen. The conductive material having may be used in a single layer or a laminate. Also, the layer above the insulator 283 Impurities such as water and hydrogen contained in the material can form oxides through conductors 240a and 240b. This can prevent contamination of 230.

[0159] Insulators 241a and 241b can be used as insulator 275, etc. A barrier insulating film can be used. For example, as insulator 241a and insulator 241b, Insulators such as silicon nitride, aluminum oxide, and silicon nitride oxide can be used. Body 241a and insulator 241b are insulators 283, 282, and 271 Since it is installed in contact with the conductor, impurities such as water and hydrogen contained in the insulator 280, etc. This can suppress the mixing of 240a and 240b into the oxide 230. In particular, silicon nitride is preferred because it has high blocking properties for hydrogen. This prevents oxygen contained in the edge 280 from being absorbed by the conductors 240a and 240b. It is possible.

[0160] When the insulators 241a and 241b are arranged in a laminated structure as shown in Figure 1B, The first insulator in contact with the inner wall of the opening such as the edge body 280, and the second insulator inside it, are oxygen It is preferable to use a combination of a barrier insulating film against hydrogen and a barrier insulating film against hydrogen. stomach.

[0161] For example, as the first insulator, aluminum oxide film formed by the ALD method is used, and the second As an insulator, silicon nitride deposited by the PEALD method can be used. This suppresses the oxidation of the conductor 240, and furthermore, prevents hydrogen from being mixed into the conductor 240. This can be reduced.

[0162] 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 have a laminated structure, for example, titanium or nitride. The titanium and the conductive material may be laminated. The conductor is provided on the insulator. It may be formed to be embedded in the opening.

[0163] <Component materials for semiconductor devices> The following describes the constituent materials that can be used in semiconductor devices.

[0164] <<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. It is also possible to provide elements on the substrate such as capacitive elements, resistive elements, switching elements, and light-emitting elements. These include children, memory elements, etc.

[0165] <<Insulator>> Insulators include insulating oxides, nitrides, oxidized nitrides, nitride oxides, and metal oxides. Examples include metal oxides, metal nitrides, and metal nitride oxides.

[0166] 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.

[0167] 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.

[0168] Furthermore, examples of insulators with low dielectric constant include silicon oxide, silicon oxide nitride, and silicon nitride oxide. Silicon oxide, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, Silicon oxide with added carbon and nitrogen, porous silicon oxide, or resins, etc. be.

[0169] 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.

[0170] 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.

[0171] <<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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] <<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.

[0176] 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.

[0177] 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.

[0178] In this specification, metal oxides containing nitrogen are also referred to as metal oxides (metal oxides). They are sometimes collectively referred to as metal oxynitrides (metal oxides). Also, metal oxides containing nitrogen are sometimes called metal oxynitrides (metal oxides). It may also be called tal oxynitride.

[0179] <Classification of crystal structures> First, we will explain the classification of crystal structures in oxide semiconductors using Figure 3A. Figure 3A 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.

[0180] As shown in Figure 3A, 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.

[0181] The structures within the thick frame shown in Figure 3A 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 Unlike stable "Amorphous" and "Crystal," these are completely different. This can be rephrased as having different structures.

[0182] 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 3B. 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 3B will be used. The resulting XRD spectrum will simply be referred to as the XRD spectrum. Note that the CAA shown in Figure 3B 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 3B is 500 nm.

[0183] In Figure 3B, the horizontal axis is 2θ [deg.] and the vertical axis is intensity [a .u.] As shown in Figure 3B, the XRD spectrum of the CAAC-IGZO film is A peak indicating clear crystallinity is detected. Specifically, the XRD of the CAAC-IGZO film... In the vector, a peak indicating c-axis orientation is detected near 2θ = 31°. (See Figure 3B) As shown, the peak near 2θ=31° is located on the left and right sides of the axis where the peak intensity was detected. It is symmetrical.

[0184] 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 3C. Figure 3C 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 3C. 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.

[0185] As shown in Figure 3C, the diffraction pattern of the CAAC-IGZO film shows multiple c-axis orientations. Spots of this nature are observed.

[0186] <<Oxide semiconductor structure>> Note that oxide semiconductors may be classified differently from those shown in Figure 3A 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.

[0187] Here, we will provide details on the CAAC-OS, nc-OS, and a-like OS mentioned above. Then, I will give an explanation.

[0188] [CAAC-OS] CAAC-OS has multiple crystalline regions, and these multiple crystalline regions have their c-axis 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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.

[0193] 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 it is not the case, and the substitution of metal atoms changes the bond distance between atoms, etc. Therefore, it is thought that this is because distortion can be tolerated.

[0194] 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 must contain Zn. A configuration such as the above is preferred. For example, 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.

[0195] 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 decreases due to the inclusion of impurities or the generation of defects. Because this can sometimes occur, CAAC-OS is an oxide with fewer impurities and defects (such as oxygen deficiencies). It can also be called a semiconductor. Therefore, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. CAAC-OS can withstand high temperatures (so-called thermal budget) in the manufacturing process. It is stable. Therefore, when using CAAC-OS in OS transistors, the manufacturing process is stable. This will broaden the scope of possibilities.

[0196] [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 may be indistinguishable from OS or amorphous oxide semiconductors. For example, in an nc-OS film... In contrast, when structural analysis is performed using an XRD device, out-of- In plane XRD measurements, no peaks indicating crystallinity were detected. Furthermore, the nc-OS film... In contrast, electron beams with probe diameters larger than those of nanocrystals (e.g., 50 nm or more) are used. When linear diffraction (also called limited-field electron diffraction) is performed, diffraction patterns such as halo patterns are observed. On the other hand, for the nc-OS film, the size is close to or smaller than that of the nanocrystals. Electron diffraction (nanobi) is a method that uses electron beams with a probe diameter (e.g., 1 nm to 30 nm). Also called electron diffraction. When this is performed, a ring-shaped region is formed around the direct spot. In some cases, an electron diffraction pattern may be obtained in which multiple spots are observed within the same area.

[0197] [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.

[0198] <<Oxide Semiconductor Composition>> Next, we will explain the details of CAC-OS mentioned above. Note that CAC-OS is a material composition. Regarding achievement.

[0199] [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. .

[0200] 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.

[0201] 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.

[0202] 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.

[0203] Note that a clear boundary may not be observed between the first region and the second region described above. .

[0204] 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.

[0205] 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.

[0206] 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.

[0207] <Transistors containing oxide semiconductors> Next, we will explain the case where the above oxide semiconductor is used in a transistor.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] Furthermore, the time required for charges trapped in the trap levels of an oxide semiconductor to disappear is also important. It can persist for a long time, behaving 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.

[0212] 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.

[0213] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0214] In oxide semiconductors, if silicon or carbon, which are among the Group 14 elements, Defect levels are formed in oxide semiconductors. Therefore, channel formation regions in oxide semiconductors The concentration of silicon or carbon in the region and the vicinity of the interface between the region and the channel formation region of the oxide semiconductor. The concentration of silicon or carbon (concentration obtained by secondary ion mass spectrometry (SIMS)) , 2 × 10 18 atoms / cm 3 The following is preferably 2 × 10 17 atoms / cm 3 The following applies:

[0215] 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:

[0216] 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 Less than, preferably 5 x 10 18 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 More preferably 5 × 10 17 atoms / cm 3 Do the following:

[0217] 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.

[0218] 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.

[0219] <<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.

[0220] 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 crystalline structures are formed by layers created by covalent or ionic bonds. They are stacked via weaker bonds than covalent and ionic bonds, such as Ruars forces. It is a structure. Layered materials have high electrical conductivity within a unit layer, that is, two-dimensional electrical conductivity. It has high properties. It functions as a semiconductor and is a material with high two-dimensional electrical conductivity in the channel formation region. By using this, it is possible to provide a transistor with a large on-current.

[0221] 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. .

[0222] 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).

[0223] <Method for fabricating semiconductor devices> Next, Figure 7 shows a method for manufacturing a semiconductor device, which is one embodiment of the present invention, as shown in Figures 1A to 1D. This will be explained using Figures A through 18D.

[0224] In each figure, A represents the top view. Also, B represents the dashed line A1-A2 shown 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 length direction. Yes. Also, C in each figure is a cross-sectional view corresponding to the area shown by the dashed line A3-A4 in A of each figure. This is also a cross-sectional view of transistor 200 in the channel width direction. In addition, D in each figure is Figure A shows a cross-sectional view of the area indicated by the dashed line A5-A6. Note that in the top view of A in each figure... Some elements have been omitted for clarity in the diagram.

[0225] In the following, insulating materials for forming an insulator and conductive materials for forming a conductor are used. Materials, or semiconductor materials for forming semiconductors, are produced by sputtering, CVD, MBE, etc. The film can be deposited using appropriate methods such as the PLD method and ALD method.

[0226] 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.

[0227] Furthermore, the CVD method includes plasma CVD (PECVD), which utilizes plasma, and heat-based CVD. Thermal CVD (TCVD) and photo-CVD (Photo-CVD) are methods that utilize light. It can be classified into methods such as CVD. Furthermore, depending on the raw material gas used, it can be classified into metal CVD (MCVD). :Metal CVD) method, metal organic CVD (MOCVD) method It can be divided into CVD (Chemical Vapor Deposition) methods.

[0228] 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.

[0229] 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 the EALD method can be used.

[0230] CVD and ALD methods involve sputtering, where particles emitted from a target or other source are deposited. This method differs from the smearing method. Therefore, it is less affected by the shape of the workpiece and provides good step coverage. This is a film deposition method that has excellent step coverage and excellent thickness uniformity. Because it has this feature, it is suitable for covering the surface of an opening with a high aspect ratio. Furthermore, because the ALD method has a relatively slow film deposition rate, other film deposition methods such as CVD, which have a faster deposition rate, are less suitable. In some cases, it is preferable to use it in combination with the law.

[0231] Furthermore, with the CVD method, films of any composition can be formed by adjusting the flow rate ratio of the raw material gas. It is possible. For example, in the CVD method, by changing the flow rate ratio of the raw material gas while depositing the film, This allows for the formation of films with continuously changing compositions. By changing the flow rate ratio of the raw material gas... When forming a film, compared to forming a film using multiple deposition chambers, the time required for transport and pressure adjustment is significantly reduced. Because no processing time is required, the time required for film deposition can be shortened. Therefore, semiconductor In some cases, it may be possible to increase the productivity of the equipment.

[0232] Furthermore, the ALD method involves simultaneously introducing multiple different types of precursors, or introducing multiple different precursors. By controlling the number of cycles for each precursor, films of any desired composition can be deposited using several types of precursors. It is possible.

[0233] First, a substrate (not shown) is prepared, and an insulator 212 is deposited on the substrate (Figure 7A). (See Figure 7D.) 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-containing molecules in the film deposition gas. The hydrogen concentration in the insulator 212 can be reduced. However, the film formation of the insulator 212 is This is not limited to the puttering method, but also includes CVD, MBE, PLD, ALD, etc. You may use it as appropriate.

[0234] 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.

[0235] 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 conductive 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.

[0236] Next, an insulator 214 is deposited on the insulator 212 (see Figures 7A to 7D). Insulator The deposition of 214 is preferably carried out using the sputtering method. The deposition gas contains hydrogen. By using a sputtering method that does not require molecules, the hydrogen concentration in insulator 214 can be increased. This can be reduced. However, the deposition of the insulator 214 is limited to the sputtering method. Instead, methods such as CVD, MBE, PLD, and ALD may be used as appropriate.

[0237] 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 That's all for now. 1. 86W / cm 2 The following applies: In other words, the RF power during the formation of the insulator 214 causes the traction The amount of oxygen injected can be varied to suit the characteristics of the transistor. It can inject an amount of oxygen suitable for improving the reliability of the device. Also, the RF frequency is 10M A frequency of Hz or higher is preferable. A typical example is 13.56 MHz. The higher the RF frequency, the better the base This can reduce the damage inflicted on the board.

[0238] 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.

[0239] Next, an insulator 216 is deposited on the insulator 214. The insulator 216 is deposited by sputtering. It is preferable to use a spar method. Spam does not require the use of hydrogen-containing molecules in the film formation gas. The tarring method can be used to reduce the hydrogen concentration in the insulator 216. However, Furthermore, the deposition of the insulator 216 is not limited to the sputtering method, but can also be done by CVD, MB, etc. Methods such as the E method, PLD method, and ALD method may be used as appropriate.

[0240] 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.

[0241] 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. .

[0242] Next, an opening is formed in the insulator 216 that reaches the insulator 214. The opening is, for example, a groove. This also includes slits, etc. Furthermore, the term "opening" can also refer to the region where an opening is formed. Yes. The opening can be formed using wet etching, but dry etching is preferable. This is preferable for microfabrication. Also, the insulator 214 is made by etching the insulator 216 to create grooves. It is preferable to select an insulator that functions as an etching stopper film during formation. For example, if silicon oxide or silicon oxide-nitride is used for the insulator 216 that forms the groove. For the insulator 214, silicon nitride, aluminum oxide, or hafnium oxide may be used.

[0243] 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.

[0244] After the opening is formed, a conductive film is deposited to form the conductive material 205a. The film preferably contains a conductor that has the function of suppressing oxygen permeation. For example, nitride Tal, tungsten nitride, titanium nitride, etc. can be used. Alternatively, oxygen permeability Conductors that have a function to suppress [something], and tantalum, tungsten, titanium, molybdenum, aluminum It can be a multilayer film of aluminum, copper, and molybdenum tungsten alloy. Conductor 20 The conductive film (5a) is deposited using sputtering, CVD, MBE, PLD, or ALD. This can be done using laws and other means.

[0245] In this embodiment, titanium nitride is deposited as a conductive film that will become the conductor 205a. By using metal nitride as the lower layer of the conductor 205b, the insulator 216 and the like This can suppress the oxidation of the conductor 205b. Also, as the conductor 205b Even when using easily diffusive metals such as copper, the diffusion of the metal from the conductor 205a to the outside is not possible. It can be prevented.

[0246] Next, a conductive film that will become the conductor 205b is formed. The conductive film that will become the conductor 205b is Tantalum, tungsten, titanium, molybdenum, aluminum, copper, molybdenum tungsten Stainless steel alloys and the like can be used. The conductive film can be formed by plating or sputtering. This can be done using methods such as CVD, MBE, PLD, and ALD. In this configuration, tungsten is deposited as a conductive film that will become the conductor 205b.

[0247] Next, by performing CMP treatment, a conductive film that becomes conductor 205a and conductor 205b are formed. A portion of the conductive film is removed, exposing the insulator 216 (see Figures 7A to 7D). As a result, conductive material 205a and conductive material 205b remain only in the opening. The P treatment may remove a portion of the insulator 216.

[0248] Next, an insulator 222 is formed on the insulator 216 and the conductor 205 (Figures 8A to 8A). See 8D.) As insulator 222, one or both of aluminum and hafnium It is preferable to form an insulating film containing an oxide. Furthermore, one of aluminum and hafnium may be used. The insulators containing oxides of both materials include aluminum oxide, hafnium oxide, and aluminum. It is preferable to use an oxide containing hafnium (hafnium aluminate), etc. Insulators containing oxides of either or both aluminum and hafnium are suitable for use with oxygen and hydrogen. , and has barrier properties against water. The insulator 222 has barrier properties against hydrogen and water. By having this, hydrogen contained in the structure provided around transistor 200, The diffusion of water into the transistor 200 through the insulator 222 is suppressed, and oxidation This can suppress the formation of oxygen deficiencies in substance 230.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] In this embodiment, as a heat treatment, after the film formation of the insulator 222, nitrogen gas and oxygen gas are used. The treatment is performed at a temperature of 400°C for 1 hour with a flow rate ratio of 4 slm: 1 slm. This method allows for the removal of impurities such as water and hydrogen contained in the insulator 222. Furthermore, when using an oxide containing hafnium as the insulator 222, the heat treatment will In some cases, a portion of the insulator 222 may crystallize. Also, the heat treatment of the insulator 224 This can also be done at other times, such as after film deposition.

[0253] Next, an insulating film 224A is deposited on the insulator 222 (see Figures 8A to 8D). Film 224A is deposited using methods such as sputtering, CVD, MBE, PLD, and ALD. This can be done using sputtering. In this embodiment, the insulating film 224A is sputtered. A silicon oxide film is deposited using this method. It is not necessary to use hydrogen-containing molecules as the deposition gas. By using the puttering method, the hydrogen concentration in the insulating film 224A can be reduced. Since the insulating film 224A comes into contact with the oxide 230a in a later process, the hydrogen concentration is reduced in this way. It is preferable that this be done.

[0254] Next, oxide films 230A and 230B are sequentially deposited on the insulating film 224A (Figure 8A). (See Figure 8D.) 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 230A 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.

[0255] 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. Oxide film 230A and oxide film 2 For 30B film deposition, the ALD method is used to deposit grooves and openings with a large aspect ratio. Even if a film of uniform thickness is formed, it is preferable. Furthermore, the PEALD method is used. This allows for the formation of oxide films 230A and 230B at lower temperatures compared to the thermal ALD method. This is preferable because it allows for this. In this embodiment, oxide film 230A and oxide film 230B The film deposition is performed using the sputtering method.

[0256] 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.

[0257] 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%.

[0258] 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 present invention is not limited thereto. 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.

[0259] 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] Oxide targets of ], In:Ga:Zn=1:1:1 [atomic ratio] oxide targets Alternatively, using an oxide target with an atomic ratio of In:Ga:Zn = 1:1:0.5 The film is formed. Note that each oxide film can be formed by appropriately selecting the film formation conditions and atomic ratio. It is preferable to form 30a and oxide 230b according to the desired properties.

[0260] Furthermore, the insulating film 224A, oxide film 230A, and oxide film 230B are not exposed to the atmosphere. However, it is preferable to deposit the film by sputtering. For example, a multi-chamber system A film deposition apparatus can be used. This will produce an insulating film 224A, an oxide film 230A, and an oxide film Regarding 230B, it is possible to reduce the incorporation of hydrogen into the film between each film deposition process. .

[0261] Next, it is preferable to perform a heat treatment. The heat treatment is performed on oxide film 230A and oxide film 2 The process should be carried out within a temperature range in which 30B does not undergo polycrystallization, preferably between 250°C and 650°C. The heat treatment should be carried out at a temperature between 400°C and 600°C. Note that the heat treatment should be performed using nitrogen gas or an inert gas. A smoky atmosphere, or an atmosphere containing oxidizing gases at a concentration of 10 ppm or more, 1% or more, or 10% or more. It is carried out in an atmosphere. For example, when performing heat treatment in a mixed atmosphere of nitrogen gas and oxygen gas, the oxygen gas It should be set to about 20%. Also, the heat treatment may be carried out under reduced pressure. Alternatively, the heat treatment The process involves heating in a nitrogen or inert gas atmosphere, followed by replenishing the desorbed oxygen. Heat treatment is performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas. You may go.

[0262] 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 and other substances are incorporated into oxide film 230A and oxide film 230B, etc. This can prevent it as much as possible.

[0263] In this embodiment, the flow rate ratio of nitrogen gas to oxygen gas is set to 4 slm:1 sl as the heat treatment. The process is carried out at a temperature of 400°C for 1 hour, as m. Therefore, impurities such as carbon, water, and hydrogen in oxide films 230A and 230B are reduced. This allows for the reduction of impurities in the film, thereby improving the crystal structure of oxide film 230B. This improves the properties and allows for a denser, more compact structure. This results in the oxide film 2 The crystalline regions in 30A and oxide film 230B are increased, and oxide film 230A and oxide film 23 In 0B, in-plane variation of the crystal region can be reduced. Therefore, the transient This can reduce in-plane variations in the electrical characteristics of the Ta200.

[0264] Next, a conductive film 242A is deposited on the oxide film 230B (see Figures 8A to 8D). The deposition of Electrode 242A can be performed using sputtering, CVD, MBE, PLD, ALD, etc. This can be done using the following method. For example, the conductive film 242A can be produced using the sputtering method. A tantalum nitride film can be deposited. Note that even if heat treatment is performed before depositing the conductive film 242A, Good. The heat treatment is carried out under reduced pressure and without exposure to the atmosphere, continuously applying the conductive film 242 A may be formed into a film. By performing such a process, adsorption occurs on the surface of the oxide film 230B. It removes the water and hydrogen present, and further removes the water from oxide film 230A and oxide film 230B. The concentration and hydrogen concentration can be reduced. The heat treatment temperature is 100°C or higher. A temperature of 0°C or lower is preferred. In this embodiment, the heat treatment temperature is set to 200°C.

[0265] Next, an insulating film 271A is deposited on the conductive film 242A (see Figures 8A to 8D). The edge film 271A is deposited using sputtering, CVD, MBE, PLD, or ALD. This can be done using methods such as the law. The insulating film 271A has the function of suppressing oxygen permeation. It is preferable to use an insulating film. For example, as insulating film 271A, the sputtering method Therefore, a film of aluminum oxide or silicon nitride should be deposited.

[0266] Furthermore, the conductive film 242A and the insulating film 271A are sputtered without being exposed to the atmosphere. It is preferable to deposit the film using the ring method. For example, a multi-chamber type film deposition apparatus can be used. This is sufficient. This reduces the hydrogen content in the conductive film 242A and the insulating film 271A. This method allows for the formation of a film and further reduces the incorporation of hydrogen into the film between each film formation step. Furthermore, when a hard mask is provided on the insulating film 271A, the film that will become the hard mask is also exposed to the atmosphere. The film can be deposited continuously without exposure to the light.

[0267] Next, using lithography, the insulating film 224A, oxide film 230A, and oxide film 230B were obtained. The conductive film 242A and insulating film 271A are processed into island shapes to form an insulator 224 and an oxide 23 0a, oxide 230b, conductive layer 242B, and insulating layer 271B are formed (Figure 9A to See Figure 9D. Here, insulator 224, oxide 230a, oxide 230b, conductive layer 24 2B and the insulating layer 271B are formed such that at least a portion of them overlap with the conductor 205. The above processing can be performed using either a dry etching method or a wet etching method. The Lye etching method is suitable for microfabrication. Also, insulating film 224A, oxide film 2 30A, oxide film 230B, conductive film 242A, and insulating film 271A each have different characteristics. You may process it in this way.

[0268] 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, an electron beam or ion beam may be used. When using a beam, a mask is not required. Note that the resist mask is used for ashing. Dry etching, wet etching, dry etching After processing, wet etching is performed, or dry etching is performed after wet etching. It can be removed by performing a ching treatment.

[0269] Furthermore, a hard mask made of an insulator or conductor may be used under the resist mask. i. When using a hard mask, an insulating film that will serve as the hard mask material is placed on the conductive film 242A or This involves forming a conductive film, then forming a resist mask on top of it, and finally etching the hard mask material. This allows for the formation of a hard mask of the desired shape. (The conductive film 242A and other materials...) Ching can be done after removing the resist mask, or with the resist mask still in place. It is permissible to proceed. In the latter case, the resist mask may disappear during etching. Conductive The hard mask may be removed by etching after etching of film 242A, etc. If the hard mask material does not affect subsequent processes, or can be used in subsequent processes, it is not necessary to There is no need to remove the hard mask. In this embodiment, the insulating layer 271B is a hard mask. It is being used as a substitute for "ku".

[0270] Here, the insulating layer 271B functions as a mask for the conductive layer 242B, so Figures 9B to Figure As shown in 9D, the conductive layer 242B does not have a curved surface between the side and top surfaces. This allows, The conductors 242a and 242b shown in Figures 1B and 1D have their side and top surfaces intersecting. The ends become angular. The ends where the side and top surfaces of the conductor 242 meet become angular, Compared to the case where the part has a curved surface, the cross-sectional area of ​​the conductor 242 is larger. As a result, the conductivity Since the resistance of body 242 is reduced, the on-current of transistor 200 can be increased. Cut.

[0271] Furthermore, as shown in Figures 9B to 9D, insulator 224, oxide 230a, oxide 230 b. The cross-sections of the conductive layer 242B and the insulating layer 271B may be tapered. In this specification, a tapered shape means that at least a portion of the side surface of the structure is on the substrate surface. This refers to a shape that is angled relative to a surface. For example, the angled side and the substrate surface are It is preferable that the angle between the two surfaces (hereinafter sometimes referred to as the taper angle) is less than 90°. Edge body 224, oxide 230a, oxide 230b, conductive layer 242B, and insulating layer 271B For example, the taper angle should be between 60° and 90°. By making the surface tapered, the coating properties of the insulator 275 and other materials in subsequent processes are improved. This improves performance and reduces defects such as porosity.

[0272] However, the above is not limited to the insulator 224, oxide 230a, oxide 230b, conductive layer 2 The sides of 42B and the insulating layer 271B are arranged to be approximately perpendicular to the upper surface of the insulator 222. It may be configured as follows. By using this configuration, when providing multiple transistors 200 This makes it possible to reduce the area and increase the density.

[0273] Furthermore, the by-products generated in the etching process are insulator 224, oxide 230a, and acid When formed in layers on the sides of the ion 230b, conductive layer 242B, and insulating layer 271B Yes. In this case, the layered by-products are insulator 224, oxide 230a, oxide 230 b, the conductive layer 242B and the insulating layer 271B are formed between the insulator 275. Therefore, the layered by-product formed in contact with the upper surface of the insulator 222 can be removed. This is preferable.

[0274] Next, insulator 224, oxide 230a, oxide 230b, conductive layer 242B, and insulation A film of insulator 275 is formed over layer 271B (see Figures 10A to 10D). The insulator 275 is preferably in close contact with the upper surface of the insulator 222 and the side surface of the insulator 224. The insulator 275 is deposited using sputtering, CVD, MBE, PLD, and AL. This can be done using methods such as Method D. The insulator 275 has the function of suppressing oxygen permeation. It is preferable to use an insulating film. For example, as the insulator 275, a sputtering method is used. Then, an aluminum oxide film is formed, and silicon nitride is formed on top of it using the PEALD method. This is sufficient. By making the insulator 275 into such a layered structure, impurities such as water and hydrogen can be filtered out. Furthermore, the function of suppressing oxygen diffusion may be improved.

[0275] In this way, oxide 230a, oxide 230b, and conductive layer 242B are made of oxygen It can be covered with an insulator 275 and an insulating layer 271B, which have the function of suppressing diffusion. This allows the insulator 224, oxide 230a, oxide 230b, and in subsequent processes, This reduces the direct diffusion of oxygen from the insulator 280 to the conductive layer 242B. .

[0276] Next, an insulating film, which will become an insulating film 280, is formed on the insulating film 275. This can be done using methods such as sputtering, CVD, MBE, PLD, and ALD. Yes, it is possible. For example, if silicon oxide is deposited 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. In addition, hydrogen can be used as the film-forming gas. By using a sputtering method that does not require the use of molecules containing hydrogen, the hydrogen in insulator 280 can be removed. The concentration can be reduced. Furthermore, heat treatment may be performed before the deposition of the insulating film. Even if the heat treatment is performed under reduced pressure and the insulating film is deposited continuously without exposure to the atmosphere, Good. By performing this process, moisture adsorbed on the surface of the insulator 275 can be removed. and remove hydrogen, and further remove oxide 230a, oxide 230b, and insulator 224 The moisture and hydrogen concentrations can be reduced. The heat treatment described above Reasonable conditions can be used.

[0277] Next, the insulating film that will become the insulator 280 is subjected to CMP treatment, and the insulator 280 has a flat top surface. Form (see Figures 10A to 10D). 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.

[0278] Next, a portion of the insulator 280, a portion of the insulator 275, a portion of the insulating layer 271B, and the conductive layer 24 A portion of 2B is processed to form an opening that reaches oxide 230b. This opening is connected to conductor 2 It is preferable to form it so as to overlap with 05. By forming the opening, the insulator 271a , forming an insulator 271b, a conductor 242a, and a conductor 242b (Figures 11A to 11A) See 11D.

[0279] Here, as shown in Figures 11B and 11C, insulator 280, insulator 275, insulator The sides of 271 and the conductor 242 may be tapered. Also, the insulator 28 The taper angle of 0 may be larger than the taper angle of conductor 242. Also, see Figure 11. Although not shown in Figures A to 11C, when forming the above-mentioned opening, the upper part of oxide 230b It may be removed.

[0280] Furthermore, a portion of the insulator 280, a portion of the insulator 275, a portion of the insulating layer 271B, and conductive Part of layer 242B is processed using either a dry etching method or a wet etching method. It is possible. Dry etching is suitable for microfabrication. These may be carried out under different conditions. For example, a portion of the insulator 280 may be dry-etched. The process involves wet etching a portion of the insulator 275 and a portion of the insulating layer 271B. The material may be processed by a conventional method, and a portion of the conductive layer 242B may be processed by a dry etching method.

[0281] Here, the side surface of oxide 230a, the top and side surfaces of oxide 230b, and the side of conductor 242. Adhesion of impurities to surfaces, the sides of the insulator 280, etc., or diffusion of such impurities into these surfaces. This may occur. A process to remove such impurities may be performed. Also, the above-mentioned In some cases, etching can create damaged areas on the oxide 230b surface. The region may be removed. The impurities include insulator 280, insulator 275, and insulating layer 27 A portion of 1B and components contained in the conductive layer 242B, used when forming the above-mentioned opening Components contained in the materials used in the device, and components contained in the gases or liquids used for etching. Examples of impurities include those caused by certain components. For example, hafnium, a Examples include aluminum, silicon, tantalum, fluorine, and chlorine.

[0282] 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.

[0283] 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.

[0284] 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.

[0285] In the etching process described above, in order to remove impurities and other substances attached to the surface of oxide 230b, washing A cleaning process is performed. The cleaning method is wet cleaning (wet etching) using a cleaning solution, etc. It can also be called processing. Examples include plasma treatment using plasma, and cleaning by heat treatment. Yes, and the above cleaning methods may be combined as appropriate. Note that the above grooves may be cleaned by this cleaning process. The section may become more in-depth.

[0286] 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.

[0287] In this specification, etc., an aqueous solution obtained by diluting hydrofluoric acid with pure water is referred to as diluted hydrofluoric acid. Furthermore, an aqueous solution obtained by diluting ammonia water with pure water is sometimes called diluted ammonia water. The concentration and temperature of the aqueous solution depend on the impurities to be removed and the configuration of the semiconductor device being cleaned. Therefore, it should be adjusted as appropriate. The ammonia concentration of the diluted ammonia solution should be between 0.01% and 5%. The following is preferable: 0.1% to 0.5%. Also, the dilution of hydrofluoric acid The hydrogen dioxide concentration is 0.01 ppm to 100 ppm, preferably 0.1 ppm to 100 ppm. It should be less than ppm.

[0288] For ultrasonic cleaning, frequencies of 200 kHz or higher are preferred, and frequencies of 900 kHz or higher are used. It is preferable to have this. Using this frequency reduces damage to oxides such as 230b. This can be reduced.

[0289] 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.

[0290] In this embodiment, as the above cleaning process, wet cleaning is performed using diluted ammonia water. By performing this cleaning treatment, the oxides 230a and 230b adhering to the surface will be removed. This can remove impurities that have diffused into the interior. Furthermore, it improves the crystallinity of oxide 230b. It is possible to do so.

[0291] Heat treatment may be performed after the etching or cleaning described above. 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 Missing (V) O This can reduce oxides. Furthermore, by performing this heat treatment, The crystallinity of 230b can be improved. Furthermore, the heat treatment may be performed under reduced pressure. Alternatively, the material can be heated in an oxygen atmosphere, followed by continuous heating in a nitrogen atmosphere without exposure to the atmosphere. You may proceed with the processing.

[0292] Next, the insulating film 252A is deposited (see Figures 12A to 12D). The insulating film 252A is, Deposition of films using methods such as sputtering, CVD, MBE, PLD, and ALD. This can be achieved. The insulating film 252A is preferably deposited using the ALD method. As mentioned above, The edge film 252A is preferably formed with a thin film thickness, so that variations in film thickness are minimized. It is necessary to do this. In contrast, the ALD method involves a precursor and a reactant (e.g., oxidation This is a film deposition method in which a substance (such as a chemical agent) is introduced alternately, and the number of times this cycle is repeated determines the film thickness. Because the thickness can be adjusted, precise film thickness control is possible. Also, see Figure 12B and Figure As shown in 12C, the insulating film 252A is located at the bottom surface of the opening formed in the insulator 280, etc. The sides need to be coated with a film that provides good coverage. In particular, the top and sides of the oxide 230, and the conductive It is preferable that a film is formed on the sides of the body 242 with good coverage. The bottom surface and sides of the opening. In this configuration, layers of atoms can be deposited one by one, so the insulating film 252A can be opened at the opening. It can form a film with good coverage.

[0293] Furthermore, when insulating film 252A is deposited by the ALD method, ozone (O3) and acid are used as oxidizing agents. Hydrogen (O2), water (H2O), etc. can be used. Ozone (O3) does not contain hydrogen. By using oxygen (O2) or other oxidizing agents, the amount of hydrogen diffusing into oxide 230b is reduced. It is possible.

[0294] In this embodiment, aluminum oxide is used as the insulating film 252A and deposited by thermal ALD method. do.

[0295] Next, it is preferable to perform microwave processing in an oxygen-containing atmosphere (Figures 12A to 12A). (See D). Here, microwave processing refers to, for example, generating a high-density plasma using microwaves. This refers to processing using a device that has a power supply. Also, in this specification, etc., A microwave refers to an electromagnetic wave with a frequency between 300 MHz and 300 GHz. do.

[0296] As shown in Figures 12B to 12D, the dotted lines represent microwaves, RF and other high-frequency waves, oxygen plasma, etc. Or it represents oxygen radicals, etc. Microwave processing is, for example, high-density processing using microwaves. It is preferable to use a microwave processing device that has a power supply for generating a rasma. The frequency of the microwave processing device is 300 MHz or more and 300 GHz or less, preferably 2. A range of 4GHz to 2.5GHz is appropriate; for example, 2.45GHz would be suitable. (High-density plasma) By using this method, high-density oxygen radicals can be generated. Furthermore, microwave processing The power supply for applying microwaves to the laboratory equipment should preferably be between 1000W and 10000W. The power should be between 2000W and 5000W. Also, the microwave processing device should be on the substrate side. It may have a power supply for applying RF. Also, by applying RF to the substrate side, high-density plastic The oxygen ions generated by Zuma can be efficiently introduced into oxide 230b.

[0297] Furthermore, the above microwave treatment is preferably carried out under reduced pressure, with a pressure of 10 Pa or more. The processing temperature should be 000 Pa or less, preferably 300 Pa to 700 Pa. The temperature should be 750°C or lower, preferably 500°C or lower, for example, around 400°C. After oxygen plasma treatment, heat treatment may be performed continuously without exposure to the outside air. For example, heat treatment at 100°C to 750°C, preferably 300°C to 500°C. That's all you need to do.

[0298] Furthermore, for example, the above microwave processing can be carried out using oxygen gas and argon gas. Here, the oxygen flow rate ratio (O2 / (O2+Ar)) should be greater than 0% and less than or equal to 100%. That is fine. Preferably, the oxygen flow rate ratio (O2 / (O2+Ar)) should be greater than 0% and 50%. The following is recommended. More preferably, the oxygen flow rate ratio (O2 / (O2+Ar)) should be 10% or less. The above should be 40% or less. More preferably, the oxygen flow rate ratio (O2 / (O2+Ar)) The concentration should be between 10% and 30%. In this way, microwaves are used in an oxygen-containing atmosphere. By performing this process, the carrier concentration in region 230bc can be reduced. Also, In microwave processing, by preventing an excessive amount of oxygen from being introduced into the chamber... This prevents an excessive decrease in carrier concentration in regions 230ba and 230bb. can.

[0299] As shown in Figures 12B to 12D, microwave processing is performed in an oxygen-containing atmosphere. Using microwaves or high-frequency waves such as RF, oxygen gas is turned into plasma, and the oxygen plasma It is possible to apply the agent to the region between the conductors 242a and 242b of oxide 230b. It is possible to irradiate region 230bc with microwaves or high-frequency waves such as RF at this time. Yes, it is possible. In other words, in the region 230bc shown in Figure 2A, microwaves or high-frequency waves such as RF are applied. It is possible to apply oxygen plasma, etc. Through the action of plasma, microwaves, etc., V in region 230bc O By cleaving H, hydrogen H can be removed from region 230bc. In other words, in region 230bc, "V O H → H + V O The reaction " occurred in area 23 V included in 0bc O H can be reduced. Therefore, oxygen deficiency in region 230bc , and V O This can reduce H and lower the carrier concentration. Also, region 230b In the oxygen vacancy formed in c, oxygen radicals generated by the oxygen plasma, or insulator 2 By supplying oxygen contained in 50, the oxygen deficiency in region 230bc is further reduced. This can reduce the carrier concentration.

[0300] On the other hand, in regions 230ba and 230bb shown in Figure 2A, there is a conductor 242a and A conductor 242b is provided. Here, the conductor 242 is in an oxygen-containing atmosphere. When performing microwave processing, it preferably functions as a shielding film against the action of high-frequency waves such as microwaves and RF, and oxygen plasma. For this reason, the conductor 242 preferably has a function of shielding electromagnetic waves of 300 MHz or more and 30 GHz or less, for example, 2.4 GHz or more and 2.5 GHz or less.

[0301] As shown in FIGS. 12B to 12D, since the conductor 242a and the conductor 242b shield the action of microwaves or high-frequency waves such as RF and oxygen plasma, these actions do not reach the regions 230ba and 230bb. As a result, by microwave processing, in the regions 230ba and 230bb, the reduction of VH and the supply of an excessive amount of oxygen do not occur, so that a decrease in carrier concentration can be prevented. O

[0302] In addition, an insulator 252 having barrier properties against oxygen is provided in contact with the side surfaces of the conductor 242a and the conductor 242b. Thereby, by microwave processing, formation of an oxide film on the side surfaces of the conductor 2 42a and the conductor 242b can be suppressed.

[0303] As described above, oxygen deficiency and VH can be selectively removed in the region 230bc of the oxide semiconductor, and the region 230bc can be made i-type or substantially i-type. Further, excessive O H oxygen is suppressed from being supplied to the regions 230ba and 230bb that function as the source region or the drain region, and n-type conversion can be maintained. Thereby, fluctuations in the electrical characteristics of the transistor 200 can be suppressed, and variations in the electrical characteristics of the transistor 200 within the substrate surface can be suppressed. ​​​​​​​​​​

[0304] Furthermore, in microwave processing, the electromagnetic interaction between microwaves and molecules in oxide 230b Depending on the application, thermal energy may be directly transferred to oxide 230b. Ghee may heat oxide 230b. Such heat treatment is performed using microwaves. This is sometimes called annealing. Microwave treatment is performed in an oxygen-containing atmosphere, which means that oxygen In some cases, an effect equivalent to annealing can be obtained. Also, in the case where oxide 230b contains hydrogen... In combination, this thermal energy is transferred to the hydrogen in oxide 230b, and the activated hydrogen is It is thought that it may be released from oxide 230b.

[0305] Next, the insulating film 250A is deposited (see Figures 13A to 13D). Deposition of insulating film 250A A heat treatment may be performed beforehand, and this heat treatment should be carried out under reduced pressure and without exposure to the atmosphere. The insulating film 250A may be deposited continuously. Furthermore, the heat treatment may be carried out in an oxygen-containing atmosphere. It is preferable to carry this out. By performing such a process, the surface of the insulating film 252A and The water and hydrogen adsorbed on it are removed, and further oxides 230a and 230b are removed. The moisture and hydrogen concentrations inside can be reduced. The heat treatment temperature is 100°C or higher. A temperature of 400°C or lower is preferable.

[0306] Insulating film 250A is produced by sputtering, CVD, PECVD, MBE, and PLD methods. Furthermore, the film can be formed using methods such as ALD. In addition, insulating film 250A has a low hydrogen atom content. It is preferable to form the film using a film deposition method that uses reduced or removed gas. This provides insulation. The hydrogen concentration of film 250A can be reduced. The insulating film 250A is a thin film in a later process. Since the insulator 250 faces the oxide 230b via the thick insulator 252, It is preferable that the hydrogen concentration is reduced.

[0307] In this embodiment, silicon oxide nitride is used as the insulating film 250A by the PECVD method. To form a membrane.

[0308] Furthermore, when the insulator 250 is made into a two-layer laminated structure as shown in Figure 2B, the composition of the insulating film 250A After the film is formed, an insulating film that will become an insulator 250b should be deposited. The film is deposited using methods such as sputtering, CVD, MBE, PLD, and ALD. This is possible. The insulating film that becomes the insulator 250b has the function of suppressing the diffusion of oxygen. It is preferable to form it using an edge material. With this configuration, the insulator 250a This suppresses the diffusion of the contained oxygen into the conductor 260. In other words, oxide 2 This can suppress the decrease in the amount of oxygen supplied to 30. Also, the insulator 250a contains The oxidation of the conductor 260 by oxygen can be suppressed. The insulating film that becomes the insulator 250b is It can be provided using the same material as the insulator 222. For example, the insulator 250b can be provided. Hafnium oxide can be used as the insulating film by thermal ALD (Automated Laser Development).

[0309] Microwave treatment may be performed after the deposition of the insulating film 250A (see Figures 13A to 13D). ). The microwave processing conditions described above are those used after the deposition of the insulating film 252A. It may be used. Also, the microwave treatment performed after deposition of insulating film 252A is omitted. Microwave treatment may be performed after the deposition of 250A. Also, as described above, insulator 250b When an insulating film is provided, microwave treatment may be performed after film formation. The principle may also be to use the microwave processing conditions performed after the deposition of the insulating film 252A as described above. Without performing the microwave treatment that is carried out after the deposition of insulating film 252A or insulating film 250A, the insulator Microwave treatment may be performed after the deposition of the insulating film, which will have a hardness of 250b.

[0310] Furthermore, after the deposition of insulating film 252A and insulating film 250A, and the insulating film that becomes the insulator 250b, After film formation, heating treatment can be performed while maintaining a reduced pressure state after each microwave treatment. i. By performing this process, in insulating film 252A, insulating film 250A, insulator 250 To efficiently remove hydrogen from the insulating film b, oxide 230b, and oxide 230a. It is possible. Also, some of the hydrogen is conductor 242 (conductor 242a, and conductor 2 42b) Gettering may occur. Alternatively, a reduced pressure state may be maintained after microwave processing. The step of heating may be repeated multiple times in this state. By doing so, in the insulating film 252A, in the insulating film 250A, and in the insulating film that becomes the insulator 250b, This allows for more efficient removal of hydrogen from oxide 230b and oxide 230a. Furthermore, the heat treatment temperature is preferably 300°C to 500°C. The microwave treatment, i.e., microwave annealing, may also serve as the heat treatment. If oxide 230b, etc., is sufficiently heated by wave annealing, the heat treatment may be omitted. That's good too.

[0311] Furthermore, microwave processing is performed to produce insulating film 252A, insulating film 250A, and insulator 250 By modifying the film quality of the insulating film b, the diffusion of hydrogen, water, impurities, etc. can be suppressed. Therefore, post-processing such as forming a conductive film that will become the conductor 260, or post-processing such as heat treatment is possible. By principle, hydrogen, water, impurities, etc., pass through the insulator 252 to oxide 230b and oxide 23 This can suppress diffusion to areas such as 0a.

[0312] Next, the insulating film 254A is deposited (see Figures 14A to 14D). The film is deposited using methods such as sputtering, CVD, MBE, PLD, and ALD. This is possible. Insulating film 254A is deposited using the ALD method, similar to insulating film 252A. Preferably, by forming the film using the ALD method, the insulating film 254A can be covered with a thin film thickness. It can form films well. In this embodiment, silicon nitride is used as the insulating film 254A. The film is deposited using the EALD method.

[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. In terms of form, titanium nitride is deposited as a conductive film that will become the conductor 260a using the ALD method. Tungsten is deposited as a conductive film, which will become conductor 260b, using the CVD method.

[0314] Next, the insulating film 252A, insulating film 250A, insulating film 254A, conductive film are subjected to CMP processing. The conductive film that becomes body 260a and the conductive film that becomes conductor 260b are exposed by the insulator 280. By polishing to this extent, insulator 252, insulator 250, insulator 254, and conductor Forms 260 (conductor 260a and conductor 260b) (see Figures 15A to 15D). (Illuminate.) As a result, the insulator 252 is positioned to cover the opening that reaches the oxide 230b. Furthermore, the conductor 260, via the insulator 252 and the insulator 250, provides the opening. It is positioned to be embedded.

[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 252, on the insulator 250, on the conductor 260, and on the insulator 280, An insulator 282 is formed (see Figures 15A to 15D). The film deposition of the insulator 282 is performed by spa This can be done using methods such as tarring, CVD, MBE, PLD, and ALD. The insulator 282 is preferably deposited using the sputtering method. By using a sputtering method that does not require the use of molecules containing elemental particles, the water in insulator 282 can be removed. The elementary concentration can be reduced.

[0317] In this embodiment, the insulator 282 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 It is possible to improve quality.

[0318] Furthermore, the insulator 282 is deposited in an oxygen-containing atmosphere using the sputtering method. Then, oxygen can be added to the insulator 280 while the film is being formed. This allows the insulator 2 Excess oxygen can be added to 80. At this time, while heating the substrate, the insulator 28 It is preferable to form a film of 2.

[0319] Next, an etching mask is formed on the insulator 282 by lithography, and the insulation Part of body 282, part of insulator 280, part of insulator 275, part of insulator 222, and A portion of the insulator 216 is processed until the upper surface of the insulator 214 is exposed (Figures 16A to 16A). (See 16D.) This process may be performed using wet etching, but dry etching is also possible. Using this method 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 3 The heat treatment should be carried out at a temperature between 50°C and 600°C. Furthermore, this heat treatment should be performed after the formation of the 230B 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, one of the oxygen added to the insulator 280 The substance diffuses into the oxide 230 via the insulator 250, etc.

[0321] Furthermore, by performing this heat treatment, the insulator 282, insulator 280, insulator 275, insulation The insulating material is insulated from the side surface of the insulating material 280 formed by processing the body 222 and the insulating material 216. The oxygen contained in body 280, and the hydrogen bonded with that oxygen, can be released to the outside. Furthermore, hydrogen that combines with oxygen is released as water. Therefore, the hydrogen contained in insulator 280 This can reduce unwanted oxygen and hydrogen.

[0322] Furthermore, in the region where the oxide 230 overlaps with the conductor 260, the upper surface of the oxide 230 and An insulator 252 is provided in contact with the side surface. The insulator 252 provides a barrier against oxygen. Because it has this property, it is possible to reduce the diffusion of excess oxygen into the oxide 230. Therefore, to prevent an excess amount of oxygen from being supplied to region 230bc and its vicinity, This allows for the supply of elements. As a result, the side surface of the conductor 242 becomes acidic due to excess oxygen. While suppressing the transformation, an oxygen deficiency is formed in region 230bc, and V O Low H This can be reduced. Therefore, the electrical characteristics of transistor 200 are improved, and its reliability is enhanced. It can be made to happen.

[0323] On the other hand, when transistors 200 are densely integrated, one transistor 200 In some cases, the volume of the insulator 280 relative to the above may become excessively small. In this case, the above heat treatment As a result, the amount of oxygen that diffuses into oxide 230 becomes significantly smaller. There is not enough oxygen present. When oxide 230 is heated while in contact with an oxide insulator (for example, insulator 250), There is a risk that oxygen constituting oxide 230 may be desorbed. However, as shown in this embodiment... In transistor 200, in the region where oxide 230 overlaps with the conductor 260, oxide 2 An insulator 252 is provided in contact with the top and side surfaces of 30. The insulator 252 is oxygen-resistant. Because it has barrier properties, the desorption of oxygen from oxide 230 is also prevented in the above heat treatment. This can be reduced. This reduces the oxygen deficiency and V formed in region 230bc. O H can be reduced. Therefore, the electrical characteristics of transistor 200 are improved, and reliability is enhanced. It can improve sexual performance.

[0324] As described above, in the semiconductor device according to this embodiment, oxygen from the insulator 280 Whether the supply is high or low, the transistor has good electrical characteristics and good reliability. A transistor can be formed. Therefore, the electrical characteristics of transistor 200 within the substrate surface are This allows us to provide a semiconductor device that suppresses variations.

[0325] Next, an insulator 283 is formed on the insulator 282 (see Figures 17A to 17D). The insulator 283 is deposited by sputtering, CVD, MBE, PLD, or AL This can be done using methods such as Method D. 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-containing molecules in the film deposition gas. By using this, the hydrogen concentration in the insulator 283 can be reduced. This may be in multiple layers. For example, silicon nitride can be deposited using a sputtering method, A silicon nitride film may be deposited on the silicon nitride using the ALD method. By encasing the transistor 200 in insulators 283 and 214, moisture from the outside is prevented from entering. , and it can prevent hydrogen from entering.

[0326] Next, an insulator 274 is formed on the insulator 283. The insulator 274 is deposited by sputtering. This can be done using methods such as the ring method, CVD method, MBE method, PLD method, or ALD method. In this embodiment, silicon oxide is deposited as the insulator 274 by the CVD method. .

[0327] 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 17A to 17D). During the P treatment, a portion of the upper surface of the insulator 283 may be removed.

[0328] Next, an insulator 285 is formed on the insulator 274 and on the insulator 283 (Figure 18A). (See Figure 18D.) The insulator 285 was deposited by sputtering, CVD, or MBE. This can be done using methods such as PLD or ALD. The deposition of the insulator 285 is performed using... It is preferable to use the puttering method. By using a good sputtering method, the hydrogen concentration in the insulator 285 can be reduced. ru.

[0329] In this embodiment, silicon oxide is formed as the insulator 285 by sputtering. To form a membrane.

[0330] Next, insulator 271, insulator 275, insulator 280, insulator 282, insulator 283, An opening is formed in the insulator 285 that reaches the conductor 242 (see Figures 18A and 18B). The opening can be formed using lithography. Note that in Figure 18A, The shape of the opening is circular when viewed from above, but is not limited to this. For example, the opening, when viewed from above, is approximately circular in shape such as an ellipse, polygonal in shape such as a square, or square. The shape may have rounded corners, even if it is a polygon.

[0331] Next, an insulating film to become the insulator 241 is formed, and the insulating film is anisotropically etched to form an insulator. Form 241. (See Figure 18B.) 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 it. For example, aluminum oxide is deposited using the ALD method, and on there It is preferable to deposit silicon nitride using the PEALD method. Silicon nitride is hydrogen It is preferable because it has high blocking properties.

[0332] 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. In addition, the conductor 240a and conductor 240b contain the same material as the insulator 280. This prevents the diffusion of impurities such as water and hydrogen.

[0333] 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 a laminate of materials such as tungsten, molybdenum, and copper. Conductor 240a The deposition of the conductive film that will become the conductor 240b is carried out by sputtering, CVD, MBE, This can be done using methods such as the PLD method or the ALD method.

[0334] 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 285. 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 Figures 18A to 18D.) Furthermore, the CMP treatment on the upper surface of the insulator 285 Some parts may be removed.

[0335] 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.

[0336] 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. At this time, the conductors 246a and 246b and the insulator 285 do not overlap. A portion of the insulator 285 in the region may be removed.

[0337] Based on the above, a semiconductor device having the transistor 200 shown in Figures 1A to 1D is fabricated. This is possible. As shown in Figures 7A to 18D, the semiconductor device shown in this embodiment can be manufactured. By using this manufacturing method, transistor 200 can be produced.

[0338] <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.

[0339] First, Figure 1 shows the configuration of a manufacturing equipment that minimizes the inclusion of impurities during the manufacturing of semiconductor devices and other equipment. This will be explained using Figures 9 through 22.

[0340] Figure 19 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

[0341] 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, and It connects to bar 2706b, chamber 2706c, and chamber 2706d.

[0342] 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 Transport robot 2763b is installed in transport room 2704. Transport robot 2763a The transport robot 2763b can transport the substrates within the manufacturing apparatus 2700. ru.

[0343] 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 -5Below Pa, more preferably 1×10 -5 Pa or less. Also the partial pressure of gas molecules ( atoms) with a mass-to-charge ratio (m / z) of 18 in the transfer chamber 2704 and each chamber is, for example, 3×10 -5 Pa or less, preferably 1×10 -5 Pa or less, more preferably 3×10 -6 Pa or less. Further, the partial pressure of gas molecules (atoms) with m / z of 28 in the transfer chamber 2704 and each chamber is, for example, 3×10 -5 Pa or less, preferably 1×10 -5 Pa or less, more preferably 3×10 -6 Pa or less. Also, the partial pressure of gas molecules (atoms) with m / z of 44 in the transfer chamber 2704 and each chamber is, for example, 3×10 Pa or less, preferably 1×10 -5 Pa or less, more preferably 3×1 -5 0 0 -6 Pa or less.

[0344] The total pressure and partial pressure in the transfer chamber 2704 and each chamber can be measured using a mass spectrometer. For example, the quadrupole mass spectrometer (also referred to as Q-mas s) Qulee CGM-051 manufactured by ULVAC, Inc. may be used.

[0345] Also, the transfer chamber 2704 and each chamber are preferably configured to have little external leakage or internal leakage. For example, the leak rate of the transfer chamber 2704 and each chamber is 3×10 Pa·m -6 / s or less, preferably 1×10 3 Pa·m -6 / s or less. 3 Also, for example, the leak rate of gas molecules (atoms) with m / z of 18 is 1×10 Pa·m -7 -7 a·m 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.

[0346] 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 a tiny hole or a faulty seal. Internal leaks are caused by leaks from partitions such as valves within a vacuum system or by the release of gas from internal components. This is caused by [something]. In order to keep the leak rate below the above-mentioned value, external leaks and internal leaks are [something]. We need to take measures from both sides.

[0347] 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.

[0348] 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.

[0349] Alternatively, the components of the aforementioned manufacturing apparatus 2700 may be made of iron fluoride, aluminum oxide, chromium oxide, etc. Any covering will do.

[0350] 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.

[0351] 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.

[0352] 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.

[0353] Next, the cross-sectional model of chambers 2706b and 2706c is shown in Figure 20. I will explain using a diagram.

[0354] 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.

[0355] 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.

[0356] 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.

[0357] 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.

[0358] 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.

[0359] 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363] 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 16 includes, for example, RF (Radio Frequency) with frequencies such as 13.56MHz and 27.12MHz. A high frequency power supply can be used. By applying a bias to the circuit board, Ions in density plasma 2810 can efficiently reach deep into openings such as films on substrate 2811. It can be achieved.

[0364] 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.

[0365] Next, the cross-sectional model of chambers 2706a and 2706d is shown in Figure 21. I will explain using a diagram.

[0366] 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.

[0367] 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.

[0368] 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.

[0369] 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.

[0370] 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.

[0371] 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.

[0372] 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.

[0373] 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.

[0374] The microwave processing apparatus that can be used in this embodiment is not limited to the above. Figure 22 shows The microwave processing apparatus 2900 shown can be used. Quartz tube 2901, exhaust port 2819, gas supply source 2801, valve 2802, high-frequency generator Instrument 2803, waveguide 2804, gas pipe 2806, vacuum pump 2817, and valve 28 It has 18. In addition, the microwave processing apparatus 2900 has multiple substrates inside the quartz tube 2901. A substrate holder 2 that holds 2811 (2811_1 to 2811_n, where n is an integer of 2 or greater). It has 902. In addition, the microwave processing apparatus 2900 has heating on the outside of the quartz tube 2901. It may have means 2903.

[0375] The microwaves generated by the high-frequency generator 2803 are transmitted through the waveguide 2804 to the quartz tube 2 The light is directed onto the substrate located inside 901. The vacuum pump 2817 is directed via valve 2818. It is connected to the exhaust port 2819, and the pressure inside the quartz tube 2901 can be adjusted. Furthermore, the gas supply source 2801 is connected to the gas pipe 2806 via the valve 2802. Furthermore, the desired gas can be introduced into the quartz tube 2901. This allows the substrate 2811 inside the quartz tube 2901 to be heated to a desired temperature. The heating means 2903 may heat the gas supplied from the gas supply source 2801. The microwave processing device 2900 heats and microwaves the substrate 2811. The processes can be performed simultaneously. In addition, after heating the substrate 2811, microwave processing is performed. This can be done. In addition, after microwave treatment of the substrate 2811, heat treatment can be performed. It is possible to do so.

[0376] Substrates 2811_1 to 2811_n all form a semiconductor device or a memory device. It may be a processing board, or some of the boards may be dummy boards. For example, board 2811_ 1, and board 2811_n are used as dummy boards, and boards 2811_2 to boards 2811_n -1 may be used as the processing substrate. Also, substrates 2811_1, 2811_2, and 281 1_n-1 and substrate 2811_n are used as dummy substrates, and substrates 2811_3 to substrate 28 11_n-2 may be used as the processing substrate. By using a dummy substrate, microwave processing, Alternatively, during the heat treatment process, multiple processing substrates can be treated uniformly, reducing variations between processing substrates. This is preferable for the following reasons. For example, the process closest to the high-frequency generator 2803 and waveguide 2804. By placing a dummy substrate on the main substrate, the processing substrate is prevented from being directly exposed to microwaves. It is preferable because it can be controlled.

[0377] 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.

[0378] <Modified examples of semiconductor devices> In the following, an example of a semiconductor device according to one aspect of the present invention will be shown using Figures 4A to 6D. I will explain.

[0379] In each figure, A represents a top view of the semiconductor device. Also, B in each figure represents the A1-A2 shown in A of each figure. This is a cross-sectional view corresponding to the area indicated by the dashed line. Also, C in each figure corresponds to A3-A in each figure. This is a cross-sectional view corresponding to the area indicated by the dashed line in 4. Also, D in each figure corresponds to A5- in A in each figure. This is a cross-sectional view corresponding to the area indicated by the dashed line in A6. In the top view A of each figure, the diagram is clarified. Some elements have been omitted for this reason.

[0380] Furthermore, in the semiconductor devices shown in Figures A through D, the semiconductor devices shown in <Example of Semiconductor Device Configuration> are... Structures that have the same function as the structures constituting the conductor device shall be denoted by the same reference numeral. In this regard, the constituent materials of semiconductor devices are described in detail in <Examples of Semiconductor Device Configurations>. You can use the fee.

[0381] <Example 1 of a semiconductor device> The semiconductor devices shown in Figures 4A to 4D are modified examples of the semiconductor devices shown in Figures 1A to 1D. The semiconductor device shown in Figures 4A to 4D is the same as the semiconductor device shown in Figures 1A to 1D. The difference is that the insulator 282 is not provided. Therefore, the semicircular shape shown in Figures 4A to 4D In the conductive device, the insulator 283 is located on the upper surface of the conductor 260, the upper surface of the insulator 280, and the insulator 25 It is in contact with the top of 4, the top of the insulator 250, and the top of the insulator 252.

[0382] For example, by microwave treatment as shown in Figure 12 or Figure 13, the oxide 230 is sufficiently If oxygen can be supplied, an insulator 282 is provided to add oxygen to the insulator 280. Even without it, region 230bc can be effectively made i-shaped. In such a case, see Figure 4A. Alternatively, as shown in Figure 4D, by omitting the insulator 282, the semiconductor device can be manufactured. By simplifying the process, productivity can be improved.

[0383] <Modified example of a semiconductor device 2> The semiconductor devices shown in Figures 5A to 5D are modified examples of the semiconductor devices shown in Figures 1A to 1D. The semiconductor devices shown in Figures 5A to 5D are the same as the semiconductor devices shown in Figures 1A to 1D. The difference is that oxide 243 (oxide 243a, oxide 243b) is provided. Oxide 243a is provided between oxide 230b and conductor 242a, and oxide 243b is It is placed between oxide 230b and conductor 242b. Here, oxide 243a is oxidized It is preferable that it is in contact with the upper surface of material 230b and the lower surface of the conductor 242a. Also, oxide 243b is preferably in contact with the upper surface of the oxide 230b and the lower surface of the conductor 242b. stomach.

[0384] The oxide 243 preferably has the function of suppressing oxygen permeation. This suppresses oxygen permeation between the conductor 242, which functions as a drain electrode, and the oxide 230b. By arranging oxide 243 which has the function of conductor 242 and oxide 230b, This is preferable because the electrical resistance between them is reduced. It may be possible to improve the electrical properties, field-effect mobility, and reliability of 00.

[0385] Furthermore, a metal oxide containing element M may be used as oxide 243. In particular, element M Aluminum, gallium, yttrium, or tin may be used. Also, oxide 2 For oxide 243, it is preferable that the concentration of element M is higher than that of oxide 230b. Gallium oxide may be used as the oxide. In addition, In-M-Zn oxide may be used as oxide 243. Metal oxides of materials may be used. Specifically, the metal oxide used in oxide 243 Therefore, the atomic ratio of element M to In is, in the metal oxide used in oxide 230b, It is preferable that the atomic ratio of element M to n is greater than the atomic ratio of n. Also, the film thickness of oxide 243 is Preferably 0.5 nm to 5 nm, more preferably 1 nm to 3 nm, and even more preferably The size is preferably between 1 nm and 2 nm. Furthermore, oxide 243 is preferably crystalline. i. When oxide 243 is crystalline, the release of oxygen in oxide 230 is suitably suppressed. It is possible. For example, if oxide 243 has a crystalline structure such as hexagonal, then oxide In some cases, it may be possible to suppress the release of oxygen from 230.

[0386] <Modified example of semiconductor device 3> The semiconductor devices shown in Figures 6A to 6D are modified examples of the semiconductor devices shown in Figures 1A to 1D. The semiconductor device shown in Figures 6A to 6D is the same as the semiconductor device shown in Figures 1A to 1D. The difference lies in the structure in which the insulator 283 is in contact with a part of the upper surface of the insulator 212. Therefore, transistor 200 is sealed with insulator 283 and insulator 212. It is placed within the region. With the above configuration, hydrogen contained outside the sealed region will This can prevent contamination within the sealed area. Also, as shown in Figures 6A to 6D In the transistor 200 shown, the insulators 212 and 283 are provided as single layers. The present invention is not limited to the configuration shown. For example, insulator 21 2. The insulator 283 may each be provided as a laminated structure of two or more layers. .

[0387] <Examples of semiconductor device applications> Below, an example of a semiconductor device according to one aspect of the present invention will be described using Figure 23. .

[0388] Figure 23A shows a top view of the semiconductor device 500. The x-axis in Figure 23A represents transistor 2 The y-axis is taken parallel to the channel length direction, and the x-axis is taken perpendicular to the x-axis. Also, Figure 2 3B is a cross-sectional view corresponding to the area shown by the dashed line A1-A2 in Figure 23A, and tra This is also a cross-sectional view of the channel length direction of the radiator 200. Figure 23C is shown in Figure 23A as A3- This is a cross-sectional view corresponding to the area indicated by the dashed line on A4, showing the opening region 400 and its vicinity. This is also a top view. Note that in the top view of Figure 23A, some elements have been omitted for clarity. ru.

[0389] Furthermore, in the semiconductor device shown in Figures 23A to 23C, the <Example of Semiconductor Device Configuration> is shown Structures having the same function as the structures constituting the semiconductor device described above will be denoted by the same reference numeral. Regarding the components of semiconductor devices, the materials used are explained in detail in the section <Examples of Semiconductor Device Configurations>. The materials used can be used.

[0390] The semiconductor device 500 shown in Figures 23A to 23C is the same as the semiconductor device shown in Figures 1A to 1D. This is a modified version of the arrangement. The semiconductor device 500 shown in Figures 23A to 23C has an insulator 282 and The point where an opening region 400 is formed in the insulator 280 is the semiconductor shown in Figures 1A to 1D. It differs from the device. Also, a sealing portion 265 is formed so as to surround multiple transistors 200. This differs from the semiconductor device shown in Figures 1A to 1D.

[0391] The semiconductor device 500 has multiple transistors 200 arranged in a matrix, and It has multiple aperture regions 400. It also functions as the gate electrode of transistor 200. Multiple conductors 260 are provided, extending in the y-axis direction. The opening region 400 is It is formed in a region that does not overlap with the oxide 230 and the conductor 260. Also, multiple Surrounding the lunger 200, multiple conductors 260, and multiple aperture regions 400 A sealing portion 265 is formed. Note that the transistor 200, conductor 260, and opening The number, arrangement, and size of region 400 are not limited to the structure shown in Figure 23, and semiconductor You should set it appropriately according to the design of the body device 500.

[0392] As shown in Figures 23B and 23C, the sealing portion 265 is connected to a plurality of transistors 200, Remove insulators 216, 222, 275, 280, and 282. It is provided in a way that surrounds it. In other words, the insulator 283 surrounds the insulator 216 and the insulator 22 2. It is provided so as to cover the insulators 275, 280, and 282. Furthermore, in the sealing portion 265, the insulator 283 is in contact with the upper surface of the insulator 214. In 265, an insulator 274 is provided between insulator 283 and insulator 285. The top surface of 274 is approximately the same height as the top surface of the insulator 283. For this purpose, an insulator similar to insulator 280 can be used.

[0393] By using this structure, multiple transistors 200 are connected to insulator 283 and insulator 2 It can be wrapped with insulator 283 and insulator 214. , and one or more of the insulators 212 function as a barrier insulating film against hydrogen. This is preferable. This allows hydrogen contained outside the area of ​​the sealing portion 265 to enter the area of ​​the sealing portion 265. This can prevent contamination inside the container.

[0394] As shown in Figure 23C, the insulator 282 has an opening in the opening region 400. Furthermore, in the opening region 400, the insulator 280 overlaps the opening of the insulator 282, and the groove portion It may have the following: The depth of the groove in the insulator 280 is such that the upper surface of the insulator 275 is exposed at most. It is sufficient to do so, for example, to reduce the thickness to about 1 / 4 to 1 / 2 of the maximum film thickness of insulator 280. That's all you need to do.

[0395] Furthermore, as shown in Figure 23C, the insulator 283 is inside the opening region 400, and the insulator 28 It is in contact with the side surface of 2, the side surface of the insulator 280, and the upper surface of the insulator 280. Also, the opening region 4 Within 00, a portion of the insulator 274 is formed to fill the recess formed in the insulator 283. This may occur. At this time, the upper surface of the insulator 274 formed within the opening region 400 and the insulating The height of the top surface of the edge 283 may be approximately the same.

[0396] Such an opening region 400 is formed, and the insulator 280 is exposed through the opening in the insulator 282. In this state, by performing a heat treatment, oxygen is supplied to the oxide 230 while the insulator 2 A portion of the oxygen contained in 80 can be diffused outward from the opening region 400. Furthermore, channel formation occurs in the oxide semiconductor from the insulator 280 containing oxygen that is desorbed by heating. A region that functions as a region, and its vicinity, should be supplied with sufficient oxygen, and an excess amount of oxygen It is possible to prevent the supply from being cut off.

[0397] At this time, the hydrogen contained in the insulator 280 combines with oxygen and, through the opening region 400 It can be released to the outside. Hydrogen combined with oxygen is released as water. Therefore, The hydrogen contained in the insulator 280 is reduced, and the hydrogen contained in the insulator 280 is converted into oxide 230. This can reduce the risk of contamination.

[0398] Furthermore, in Figure 23A, the shape of the opening region 400 in a top view is approximately rectangular. However, the present invention is not limited thereto. For example, in a top view of the opening region 400 The shape may be a rectangle, ellipse, circle, rhombus, or a combination of these shapes. Furthermore, the area of ​​the aperture region 400 and the spacing between the semiconductor components including the transistor 200 are determined by the semiconductor equipment. It can be set appropriately according to the design of the installation. For example, if the density of transistor 200 is small In the pit area, the area of ​​the opening region 400 is increased, or the spacing between the opening regions 400 is narrowed. This is sufficient. Also, for example, in regions where the density of transistors 200 is high, the aperture region 40 This can be achieved by reducing the area of ​​0, or by widening the spacing between the opening regions 400.

[0399] According to one aspect of the present invention, a novel transistor can be provided. Or, the present invention In one embodiment, a semiconductor device with less variation in transistor characteristics can be provided. Alternatively, according to one aspect of the present invention, to provide a semiconductor device having good electrical characteristics. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device with good reliability can be provided. It is possible. Alternatively, according to one aspect of the present invention, it is possible to provide a semiconductor device with a large on-current. Yes, it is possible. Alternatively, according to one aspect of the present invention, a semiconductor device with high field-effect mobility is provided. This is possible. Alternatively, according to one aspect of the present invention, a semiconductor device with good frequency characteristics 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.

[0400] The configurations, methods, etc., described above in this embodiment are described in part in this specification. This can be implemented in appropriate combination with other embodiments and examples described herein.

[0401] (Embodiment 2) In this embodiment, one form of a semiconductor device will be described with reference to Figures 24 to 28.

[0402] [Storage device 1] An example of a semiconductor device (memory device) according to one aspect of the present invention is shown in Figure 24. 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.

[0403] 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.

[0404] In the semiconductor device shown in Figure 24, 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.

[0405] Furthermore, the memory device shown in Figure 24, when arranged in a matrix, allows the memory cell array to function as a matrix. It can be configured.

[0406] <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 p-channel or n-channel. Any type is acceptable.

[0407] Here, the transistor 300 shown in Figure 24 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 conductor 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.

[0408] Note that the transistor 300 shown in Figure 24 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.

[0409] <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 283 shown in the diagram.

[0410] Furthermore, for example, the conductor 112 provided on the conductor 240 and the conductor 110 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. The electric body 112 corresponds to the conductor 246 shown in the previous embodiment, and for details, see the The description in Electrical Unit 246 can be taken into consideration.

[0411] In Figure 24, 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.

[0412] 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.

[0413] 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.

[0414] 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.

[0415] 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.

[0416] <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.

[0417] 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.

[0418] 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.

[0419] A wiring layer may be provided on the insulator 326 and the conductor 330. For example, as shown in Figure 24. 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.

[0420] 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.

[0421] 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.

[0422] 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.

[0423] 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.

[0424] 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.

[0425] 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.

[0426] 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.

[0427] 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.

[0428] 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 An insulator containing zym, hafnium, or tantalum may be used in a single layer or in a multilayer configuration. 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. .

[0429] 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.

[0430] 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 are both electrically conductive. For example, it is preferable to use tungsten. Alternatively, aluminum or copper, etc. It is preferable to form it with a low-resistance conductive material. By using a low-resistance conductive material, wiring resistance It can be lowered.

[0431] <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.

[0432] For example, in Figure 24, 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.

[0433] 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.

[0434] 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.

[0435] 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.

[0436] 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.

[0437] <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.

[0438] Here, for example, as shown in Figure 24, the region where the insulator 283 and the insulator 214 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, insulators 282, 280, 275, 222, and 216 An opening is provided.

[0439] In other words, insulator 282, insulator 280, insulator 275, insulator 222, and insulator 2 In the opening provided in 16, the insulator 214 and the insulator 283 are in contact.

[0440] Also, for example, insulator 282, insulator 280, insulator 275, insulator 222, insulator 2 16 and the insulator 214 may have openings. With this configuration, the insulator 282, insulator 280, insulator 275, insulator 222, insulator 216, and insulator 21 At the opening provided in 4, the insulator 212 and the insulator 283 are in contact. At this time, the insulator 212 and the insulator 283 may be formed using the same material and method. Insulator 212, And by providing the insulator 283 with the same material and in the same method, adhesion can be improved. For example, silicon nitride is preferable.

[0441] 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.

[0442] 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.

[0443] In the memory device shown in Figure 24, 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 25. The shape of the capacitive element 100 may be cylindrical. Note that the memory device shown in Figure 25 is an absolute The configuration below the edge 150 is the same as that of the semiconductor device shown in Figure 24.

[0444] The capacitive element 100 shown in Figure 25 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.

[0445] 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.

[0446] 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.

[0447] 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.

[0448] The conductor 115 is positioned in contact with the openings formed in the insulator 142 and the insulator 150. It is preferable that the upper surface of the conductor 115 substantially coincides with 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. 15 is preferably formed using the ALD method or CVD method, for example, a conductive material. Any conductive material suitable for 205 should be used.

[0449] 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.

[0450] 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.

[0451] 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 45 is made thicker, 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.

[0452] On the other hand, materials with high dielectric strength include silicon oxide, silicon oxide nitride, and silicon nitride oxide. Silicon oxide, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, Examples include silicon oxide with added carbon and nitrogen, silicon oxide with voids, and resins. For example, silicon nitride (SiN) deposited using the PEALD method x ), using the PEALD method Silicon oxide (SiO2) film formed by this process x ), silicon nitride (S) deposited using the PEALD method iN x An insulating film can be used, which is stacked in the order of ). Alternatively, zirconium oxide, An insulating film, consisting of silicon oxide and zirconium oxide layered in that order, was deposited using the ALD method. It can be used. By using such an insulator with high dielectric strength, the dielectric strength This improves performance and suppresses electrostatic discharge damage to the capacitive element 100.

[0453] The conductor 125 is positioned to fill the openings formed in the insulators 142 and 150. It is placed. Also, the conductor 125 is connected to the wiring 10 via the conductor 140 and the conductor 153. It is electrically connected to 05. Conductor 125 is formed using methods such as ALD or CVD. It is preferable to form a film, for example, by using a conductor that can be used for the conductor 205. stomach.

[0454] Furthermore, the conductor 153 is provided on the insulator 154 and is covered by the insulator 156. The conductor 153 can be any conductor that can be used for the conductor 112, and the insulator 156 can be any insulator that can be used for insulator 152. Here, conductor 1 53 is in contact with the upper surface of the conductor 140, and the capacitive element 100, the transistor 200, or It functions as a terminal for transistor 300.

[0455] [Storage device 2] An example of a semiconductor device (memory device) according to one aspect of the present invention is shown in Figure 26.

[0456] <Example of memory device configuration> Figure 26 is a cross-sectional view of a semiconductor device having a memory device 290. In addition to the transistor 200 shown in Figures 1A to 1D, the Mori device 290 also includes a capacitive device It has a chair 292. Figure 26 corresponds to a cross-sectional view of transistor 200 in the channel length direction. ru.

[0457] The capacitive device 292 comprises a conductor 242b and an insulator 27 provided on the conductor 242b. 1b and in contact with the upper surface of the insulator 271b, the side surface of the insulator 271b, and the side surface of the conductor 242b It has an insulator 275 and a conductor 294 on the insulator 275. The quantity device 292 has a MIM (Metal-Insulator-Metal) capacitance configuration. It is accomplished. Furthermore, one of the pair of electrodes that the capacitive device 292 has, namely the conductor 24 2b can also serve as the source electrode of the transistor. Furthermore, the capacitive device 292 The dielectric layer is a protective layer provided on the transistor, i.e., an insulator 271, and an insulating layer. It can also serve as the edge 275. Therefore, in the manufacturing process of the capacitive device 292 Because it can also be used for part of the transistor manufacturing process, it is a highly productive semiconductor device. This can be done. Also, one of the pair of electrodes that the capacitive device 292 has, i.e., the lead Since the electrode 242b also serves as the source electrode of the transistor, the transistor and the capacitive electrode This makes it possible to reduce the area where the vise is placed.

[0458] For example, the conductor 294 may be made from a material that can be used for the conductor 242. That's all you need to do.

[0459] <Examples of memory devices> Below, using Figures 27A, 27B, and 28, we will explain the configuration of the memory device mentioned above. A transistor 200 and a capacitance 200 according to one aspect of the present invention, which differ from those shown in the example. An example of a semiconductor device having a vice 292 will be described. (See Figures 27A, 27B, etc.) In the semiconductor device shown in Figure 28, the above embodiment and the <Memory device configuration example> Structures having the same function as the semiconductor device shown (see Figure 26) are indicated by the same notation. The numbers are added. Note that in this section, transistor 200 and capacitive device 292 The constituent materials will be described in detail in the previous embodiment and in <Example of Memory Device Configuration>. The materials used can be used. Also, in Figures 27A, 27B, and 28, etc., As a memory device, the memory device shown in Figure 26 is used, but it is not limited to this. isn't it.

[0460] <<Differential Example of Memory Device 1>> In the following, transistors 200a, 200b, and capacitance according to one aspect of the present invention are described. An example of a semiconductor device 600 having device 292a and capacitive device 292b is described below. This will be explained using Figure 27A.

[0461] Figure 27A shows transistor 200a, transistor 200b, and capacitive device 292a. and a cross-sectional view in the channel length direction of the semiconductor device 600 having a capacitive device 292b. Here, the capacitive device 292a comprises a conductor 242a and an insulator 27 on the conductor 242a. 1a, the upper surface of the insulator 271a, the side surface of the insulator 271a, and the side surface of the conductor 242a It has a contacting insulator 275 and a conductor 294a on the insulator 275. Also, capacitive device Chair 292b consists of a conductor 242b, an insulator 271b on the conductor 242b, and an insulator 27 Insulator 275 in contact with the upper surface of 1b, the side surface of insulator 271b, and the side surface of conductor 242b It has a conductor 294b on an insulator 275.

[0462] As shown in Figure 27A, the semiconductor device 600 is symmetrical along the dashed line A3-A4. It has a symmetrical configuration. Either the source electrode or the drain electrode of transistor 200a And, one of the source or drain electrodes of transistor 200b is connected to the conductor 242c It has a dual-purpose configuration. Furthermore, an insulator 271c is provided on the conductor 242c. Furthermore, there is a conductor 246 that functions as wiring, transistor 200a, and transistor 2 The conductor 240, which also functions as a plug, is configured to connect to 00b. As described above, the connection between the two transistors, two capacitive devices, and the wiring and plug is as follows: By using this configuration, it is possible to provide a semiconductor device that enables miniaturization or high integration.

[0463] Transistor 200a, transistor 200b, capacitive device 292a, and capacitive device The configuration and effects of each part of Vice 292b are shown in Figure 26, which shows the configuration of the semiconductor device. Examples can be consulted.

[0464] <<Modified Memory Device 2>> In the above, transistor 200a and transistor 20 are used as examples of semiconductor device configurations. Although capacitive devices 292a and 292b were mentioned, as shown in this embodiment... The semiconductor device is not limited to this. For example, as shown in Figure 27B, a semiconductor device 600 and a semiconductor device having the same configuration as semiconductor device 600 are connected via a capacitive unit. A configuration in which transistors 200a and 200b are used is also acceptable. In this specification, transistors 200a and 200b are used. A semiconductor device having capacitive device 292a and capacitive device 292b is referred to as a cell. Transistor 200a, transistor 200b, capacitive device 292a and capacitive device The configuration of Vice 292b is as described above: transistor 200a, transistor 200b The description relating to capacitive devices 292a and 292b can be taken into consideration. .

[0465] Figure 27B shows transistor 200a, transistor 200b, and capacitive device 292a. and a semiconductor device 600 having a capacitive device 292b, and a semiconductor device 600 having a similar configuration This is a cross-sectional view in which cells having a certain component are connected via a capacity section.

[0466] As shown in Figure 27B, one electrode of the capacitive device 292b of the semiconductor device 600 The conductor 294b, which functions as a semiconductor device 6, has a configuration similar to that of semiconductor device 600. 01 has a configuration that also serves as one of the electrodes of the capacitive device. Also, although not shown in the diagram , Conductor 2 which functions as one electrode of the capacitive device 292a of semiconductor device 600 94a is adjacent to the semiconductor device 600 on the left side, i.e., in Figure 27B, in the A1 direction. It also serves as one of the electrodes of the capacitive device of the body. Furthermore, on the right side of semiconductor device 601, Furthermore, in Figure 27B, the cells in the A2 direction have a similar configuration. An array (also called a memory device layer) can be constructed. By using this configuration, the spacing between adjacent cells can be reduced, thus improving the performance of the cell array. The shadow area can be reduced, enabling high integration. Also, as shown in Figure 27B, cell allergens By arranging the components of (i) in a matrix, a matrix-like cell array is formed. It is possible.

[0467] As described above, in the configuration shown in this embodiment, transistor 200a, transistor 20 By forming capacitive device 292a and capacitive device 292b, the cell This reduces the area and enables miniaturization or high integration of semiconductor devices having cell arrays. ru.

[0468] Furthermore, the above cell array may be configured not only as a planar array but also as a stacked array. Figure 28 shows a cell array A cross-sectional view of a configuration in which n layers of I610 are stacked is shown. As shown in Figure 28, multiple cell arrays ( By stacking cell arrays 610_1 to 610_n, the cell array Cells can be clustered and arranged without increasing the occupied area. In other words, 3D cell arrangement Rays can be constructed.

[0469] The configurations, methods, etc., described above in this embodiment are described in part in this specification. This can be implemented in appropriate combination with other embodiments and examples described herein.

[0470] (Embodiment 3) In this embodiment, the present invention is described using Figures 29A, 29B, and 30A to 30H. A transistor using an oxide as a semiconductor (hereinafter referred to as an OS transistor) according to one aspect thereof. In some cases, ), and storage devices to which capacitive elements are applied (hereinafter referred to as OS memory devices) This may be the case.) The OS memory device has at least a capacitive element and a capacitive element This is a memory device having an OS transistor that controls the charging and discharging of the device. Because the current is extremely small, the OS memory device has excellent retention characteristics and is a non-volatile memory. It can be made to function.

[0471] <Example of a storage device configuration> Figure 29A shows an example of the configuration of the OS memory device. The storage device 1400 is connected to peripheral circuit 141 1, and a memory cell array 1470. Peripheral circuit 1411 is a row circuit 1420, It has a column circuit 1430, an output circuit 1440, and a control logic circuit 1460. .

[0472] The column circuit 1430 includes, for example, a column decoder, a pre-charge circuit, a sense amplifier, and a programming circuit. It has circuits, etc. The precharge circuit has the function of precharging the wiring. The amplifier has the function of amplifying the data signal read from the memory cell. The lines are wiring connected to memory cells in the memory cell array 1470, and more details The details will be explained later. The amplified data signal is sent via the output circuit 1440 to the data signal RDA. The TA is output to the outside of the storage device 1400. Also, the row circuit 1420 is, for example, row It has a decoder, a word line driver circuit, etc., and can select the row to access.

[0473] The storage device 1400 receives a low power supply voltage (VSS) from an external source as the power supply voltage, and peripheral circuits 14 The high power supply voltage (VDD) for 11 and the high power supply voltage (VIL) for the memory cell array 1470 are It is supplied. In addition, the storage device 1400 contains control signals (CE, WE, RE) and address signals. The address signal ADDR and the data signal WDATA are input from an external source. The address signal ADDR is the line The data signal WDATA is input to the decoder and column decoder, and then input to the writing circuit. ru.

[0474] The control logic circuit 1460 receives externally input control signals (CE, WE, R Process E) to generate control signals for the row decoder and column decoder. The control signal CE is a chip The write enable signal is the control signal R E is the read enable signal. The signal processed by the control logic circuit 1460 The signal is not limited to this; other control signals can be input as needed.

[0475] The memory cell array 1470 consists of multiple memory cells MC arranged in a matrix, and multiple It has the wiring. Note that the wiring connecting the memory cell array 1470 and the row circuit 1420 The number of lines is determined by the configuration of the memory cell MC, the number of memory cell MCs in a single row, and other factors. Also, the number of wires connecting the memory cell array 1470 and the column circuit 1430 is noted. This is determined by factors such as the configuration of the recell MC and the number of memory cell MCs in each row.

[0476] In Figure 29A, the peripheral circuit 1411 and the memory cell array 1470 are on the same plane. Although examples of how to form it have been shown, this embodiment is not limited to this. For example, As shown in Figure 29B, the memory cell array 1470 is superimposed on a portion of the peripheral circuit 1411. It may be provided in such a way. For example, so as to overlap below the memory cell array 1470, A configuration that includes a sense amplifier is also possible.

[0477] Figures 30A to 30H show examples of memory cell configurations applicable to the above-mentioned memory cell MC. I will explain.

[0478] [DOSRAM] Figures 30A to 30C show examples of circuit configurations for DRAM memory cells. And, DRAM using a 1OS transistor 1 capacitance element type memory cell is called DOSRAM. (Dynamic Oxide Semiconductor Random Acce. It is sometimes called ss Memory. As shown in Figure 30A, memory cell 1471 is a tra It has a transistor M1 and a capacitive element CA. Note that the transistor M1 has a gate (top It has a front gate (sometimes called a back gate) and a back gate.

[0479] The first terminal of transistor M1 is connected to the first terminal of capacitive element CA, and transistor M The second terminal of 1 is connected to wiring BIL, and the gate of transistor M1 is connected to wiring WOL. Next, the back gate of transistor M1 is connected to wiring BGL. Capacitive element C The second terminal of A is connected to wiring LL.

[0480] Wiring BIL functions as a bit line, and wiring WOL functions as a word line. LL functions as wiring for applying a predetermined potential to the second terminal of the capacitive element CA. During data writing and reading, wiring LL is at a low level potential, even at ground potential. This is also acceptable. Wiring BGL is for applying potential to the back gate of transistor M1. It functions as wiring. By applying an arbitrary potential to wiring BGL, transistor M The threshold voltage of 1 can be increased or decreased.

[0481] Here, the memory cell 1471 shown in Figure 30A corresponds to the storage device shown in Figure 26. In other words, transistor M1 becomes transistor 200, and capacitive element CA becomes capacitive device 29 It corresponds to 2.

[0482] Furthermore, the memory cell MC is not limited to memory cell 1471, and the circuit configuration can be changed. This is possible. For example, a memory cell MC can be a memory cell 1472 as shown in Figure 30B. The back gate of transistor M1 is connected to the WOL wiring instead of the BGL wiring. It is also possible to do so. For example, the memory cell MC is a memory cell 1473 as shown in Figure 30C. Uni, a single-gate transistor, that is, a transistor without a back gate. It may also be a memory cell composed of M1.

[0483] When the semiconductor device shown in the above embodiment is used as a memory cell 1471, etc., a transistor Transistor 200 is used as M1, and capacitive element 100 is used as capacitive element CA. This can be done. By using an OS transistor as transistor M1, the transistor The leakage current of the M1 can be made very small. In other words, the written data can be transmitted via Because it can be retained for a long time by the M1 converter, the frequency of memory cell refresh is reduced. The frequency can be reduced. Alternatively, the refresh operation of the memory cells can be made unnecessary. This is possible. Also, because the leakage current is very small, memory cell 1471, memory cell 14 72. Multilevel data or analog data can be stored in memory cell 1473. Cut.

[0484] Furthermore, in DOSRAM, as described above, overlaps below the memory cell array 1470 As shown, by using a configuration that includes a sense amplifier, the bit line can be shortened. This reduces the bit line capacitance and thus the memory cell retention capacity.

[0485] [NOSRAM] Figures 30D to 30G show the rotation of a gain cell type memory cell with two transistors and one capacitance element. An example of a circuit configuration is shown. As shown in Figure 30D, the memory cell 1474 is connected to transistor M2 and It has a transistor M3 and a capacitive element CB. Note that transistor M2 is the top gate ( It is sometimes simply called a gate, and has a back gate. In this specification, etc., A memory device having a gain cell type memory cell using an OS transistor in the transistor M2. , NOSRAM(Nonvolatile Oxide Semiconductor It is sometimes referred to as RAM.

[0486] The first terminal of transistor M2 is connected to the first terminal of the capacitive element CB, and transistor M The second terminal of 2 is connected to the wiring WBL, and the gate of transistor M2 is connected to the wiring WOL. Next, the back gate of transistor M2 is connected to wiring BGL. Capacitive element C The second terminal of B is connected to wiring CAL. The first terminal of transistor M3 is connected to wiring R. The second terminal of transistor M3 is connected to BL, and the wiring SL is connected to transistor M The gate of 3 is connected to the first terminal of the capacitive element CB.

[0487] Wiring WBL functions as the write bit line, and wiring RBL functions as the read bit line. The wiring WOL functions as a word line. The wiring CAL is the second of the capacitive element CB. It functions as wiring for applying a predetermined potential to the terminal. When writing data, and When reading the data, it is preferable to apply a high-level potential to the wiring CAL. Furthermore, during data retention, it is preferable to apply a low-level potential to the wiring CAL. The wiring BGL is used to apply potential to the back gate of transistor M2. It is possible. By applying an arbitrary potential to the wiring BGL, the threshold voltage of transistor M2 can be controlled. The voltage can be increased or decreased.

[0488] Here, the memory cell 1474 shown in Figure 30D is connected to the storage device shown in Figures 24 and 25. They are compatible. In other words, transistor M2 corresponds to transistor 200, and the capacitive element CB corresponds to the capacitance. Element 100, transistor M3 to transistor 300, wiring WBL to wiring 1003 Wiring WOL to wire 1004, wiring BGL to wire 1006, wiring CAL to wire 100 In section 5, wiring RBL corresponds to wiring 1002, and wiring SL corresponds to wiring 1001.

[0489] Furthermore, the memory cell MC is not limited to memory cell 1474, and the circuit configuration can be changed as appropriate. This is possible. For example, the memory cell MC is like the memory cell 1475 shown in Figure 30E. In this configuration, the back gate of transistor M2 is connected to the WOL wiring instead of the BGL wiring. It may also be made into a memory cell MC...

Claims

[Claim 1] Oxide semiconductor film and The source electrode and drain electrode on the oxide semiconductor film, An interlayer insulating film is arranged to cover the oxide semiconductor film, the source electrode, and the drain electrode, The first gate insulating film on the oxide semiconductor film, The second gate insulating film on the first gate insulating film, The gate electrode on the second gate insulating film and the gate electrode are provided, The interlayer insulating film is superimposed in the region between the source electrode and the drain electrode, and an opening is formed therein. The first gate insulating film, the second gate insulating film, and the gate electrode are arranged within the opening of the interlayer insulating film. The first gate insulating film comprises oxygen and aluminum. The first gate insulating film has a region where the film thickness is thinner than that of the second gate insulating film. The first gate insulating film is in contact with the top and side surfaces of the oxide semiconductor film, the side surfaces of the source electrode, the side surfaces of the drain electrode, and the side surfaces of the interlayer insulating film. Semiconductor equipment.

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