Liquid crystal display device

Abstract

To provide a manufacturing method for a transistor having a stable electric characteristic, having less signal delay due to wiring resistance, and including an oxide semiconductor film, a semiconductor device including the transistor, and a display device with high performance.SOLUTION: A manufacturing method for a source electrode 110 and a drain electrode 112 in contact with an oxide semiconductor film in a transistor 150 includes: forming first metal films 110a, 112a and second metal films 110b, 112b; performing a first photolithography step on the second metal films; removing a part of the second metal films by first etching; forming third metal films 110c, 112c on the first metal film and the second metal film; performing a second photolithography step on the third metal films; and removing a part of the first metal films and the third metal films by second etching. In the second etching, the first metal films and the third metal films are removed more on the outside than an end part of the second metal films removed by the first etching.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device. This document relates to equipment and electronic devices. [Background technology]

[0002] A transistor (thin film transistor) is made using a semiconductor thin film formed on a substrate with an insulating surface. The technology of constructing thin-film transistors (also called thin-film transistors (TFTs)) is attracting attention. It is widely used in electronic devices such as integrated circuits (ICs) and image display devices (display devices). Silicon-based semiconductor materials are widely known as semiconductor thin films that can be used in transistors. As another material for this, oxide semiconductors have been attracting attention.

[0003] For example, the oxide semiconductor may be a Zn-O-based oxide or an In-Ga-Zn-O-based oxide. There are disclosed techniques for fabricating transistors using the above (see Patent Documents 1 and 2). ).

[0004] In addition, in display devices using transistors (such as liquid crystal panels and organic EL panels), As screen sizes become larger, the number of active elements such as transistors has increased. In the case of a display device using an active element, the voltage applied to the element is This can lead to poor display quality, such as uneven display and poor gradation, due to differences in the position of the wiring. There was a problem.

[0005] In addition, the display device's screen resolution is high definition (HD, 1366 x 768), There is a trend towards high definition image quality (FHD, 1920 x 1080) and high resolution. 3840 x 2048 or 4096 x 2180, so-called 4K digital cinema display The development of display devices is also being rushed.

[0006] As the resolution of the display device screen improves, the driving frequency used in the driving circuit of the display device also increases. Therefore, it is desirable to use low-resistance materials that have little signal delay for wiring or signal lines. It is being done.

[0007] Conventionally, aluminum film has been widely used as a material for wiring or signal lines. However, research and development into using copper films to further reduce resistance is being actively carried out. Therefore, the copper film has poor adhesion to the undercoat film, and the copper element in the copper film is It has the disadvantage that it easily diffuses into the layer and deteriorates the transistor characteristics. In order to improve adhesion with the silicon nitride film and prevent diffusion of copper elements, the silicon nitride film is A transistor is manufactured using a copper alloy layer formed on the copper alloy layer and a pure copper layer formed on the copper alloy layer. A technique for producing the above has been disclosed (see Patent Document 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2007-123861 A [Patent Document 2] JP 2007-96055 A [Patent Document 3] JP 2010-230965 A Summary of the Invention [Problem to be solved by the invention]

[0009] In Patent Document 1, a silicon-based semiconductor is used as a semiconductor thin film applicable to a transistor. Therefore, a transistor using an oxide semiconductor film for a channel formation region is However, there are problems with the optimal fabrication method and structure for applying the technology to the sintered material. there were.

[0010] In view of the above problem, in one embodiment of the present invention, a semiconductor device including an oxide semiconductor film is A transistor that has stable electrical characteristics and has little signal delay caused by wiring resistance. Another object of the present invention is to provide a method for manufacturing a semiconductor device having the transistor. Another object of the present invention is to provide a high-performance display device having the transistor. One of the objectives is to provide. [Means for solving the problem]

[0011] A bottom-gate transistor in which an oxide semiconductor film is used for a channel formation region is provided. In a method for manufacturing a semiconductor device, a source electrode and a drain electrode are provided in contact with an oxide semiconductor film. The source electrode and the drain electrode are formed of the first to third metal films. The metal film 2 is made of a material containing copper.

[0012] As a method for forming a source electrode and a drain electrode in contact with an oxide semiconductor film, and forming a second metal film, performing a first photolithography process on the second metal film, A part of the second metal film is removed by a first etching. A third metal film is formed on the first metal film, and a second photolithography process is performed on the third metal film. Then, a part of the first metal film and a part of the third metal film are removed by a second etching. The second etching is performed on the outer side of the end of the second metal film removed by the first etching. The first metal film and the third metal film are removed on the other side. The second metal film is covered by a first metal film and a third metal film (more preferably, Therefore, the material containing copper used in the second metal film does not diffuse into the oxide semiconductor film. This can be suppressed. More specifically, it is as follows.

[0013] One aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of forming a gate electrode and forming a gate insulating film on the gate electrode. forming an oxide semiconductor film in contact with the gate insulating film and overlapping with the gate electrode; and forming a source electrode and a drain electrode on the oxide semiconductor film. In the method for fabricating a semiconductor device, the source electrode and the drain electrode are formed by a first metal film and a second metal film. forming a metal film; performing a first photolithography process on the second metal film; a step of removing a part of the metal film by a first etching; forming a third metal film on the first metal film; and performing a second photolithography process on the third metal film. and removing a portion of the first metal film and the third metal film by a second etching. The second etching is performed to remove the second metal film from the edge of the second metal film removed by the first etching. The method for manufacturing a semiconductor device includes removing the first metal film and the third metal film on the outer side.

[0014] In the above manufacturing method, a first insulating film is further formed on the source electrode and the drain electrode. forming a second insulating film on the first insulating film; forming an insulating film on the first insulating film; forming an aluminum film on the second insulating film; introducing oxygen onto the aluminum film to form an aluminum oxide film; and forming a planarizing insulating film on the aluminum film.

[0015] In the above-mentioned manufacturing methods, the first metal film and the third metal film are made of tungsten, A metal film containing one or more elements selected from the group consisting of tantalum, titanium, and molybdenum, and The first metal film may be a metal nitride film, and the second metal film may contain copper.

[0016] In the above-mentioned manufacturing methods, the first etching is performed by using a wet etching method. The second etching may be performed by a dry etching method.

[0017] Another aspect of the present invention is a gate electrode and a gate insulating film formed on the gate electrode. an oxide semiconductor film formed in contact with the gate insulating film and overlapping with the gate electrode; and a source electrode and a drain electrode formed on the nitride semiconductor film. The rain electrode is composed of a first metal film, a second metal film, and a third metal film, and the second metal film The present invention relates to a semiconductor device formed in an area inside the end of a first metal film and a third metal film. do.

[0018] Another aspect of the present invention is a gate electrode and a gate insulating film formed on the gate electrode. an oxide semiconductor film formed in contact with the gate insulating film and overlapping with the gate electrode; A source electrode and a drain electrode formed on the nitride semiconductor film, and the source electrode is electrically connected to the and a signal line formed by the first metal film, the second metal film, and the third metal film. The second metal film is formed in an area inside the ends of the first metal film and the third metal film. The source electrode and the drain electrode are made of a semiconductor material including a first metal film and a third metal film. It is a device.

[0019] In the above-mentioned configuration, a first insulator of an oxygen excess type is further provided on the source electrode and the drain electrode. an insulating film, a second insulating film formed on the first insulating film, and an oxide film formed on the second insulating film. The aluminum oxide film is formed on the aluminum film. This is also fine.

[0020] In each of the above configurations, the first metal film and the third metal film are made of tungsten, tantalum, or the like. A metal film containing one or more elements selected from the group consisting of aluminum, titanium, and molybdenum, or a metal The second metal film is preferably a nitride film, and preferably contains copper.

[0021] In each of the above structures, the gate electrode is made of tungsten, tantalum, titanium, molybdenum, etc. The alloy may contain one or more elements selected from the group consisting of nickel, zinc, zinc alloy, nickel ...

[0022] Further, a display device and an electronic device having the above-mentioned semiconductor device are also included in the scope of the present invention. . Effect of the Invention

[0023] In a semiconductor device using an oxide semiconductor film, stable electrical characteristics and wiring resistance are achieved. In addition, a method for manufacturing a transistor in which signal delay caused by the above-mentioned phenomenon is reduced can be provided. A semiconductor device including the transistor can be provided. It is possible to provide a high-performance display device having the above-mentioned features. [Brief description of the drawings]

[0024] [Figure 1] 1A and 1B are a plan view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Diagram 2] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Diagram 3] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 4] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Diagram 5] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 6] 1A and 1B are a plan view and a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 7] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 8] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 9] FIG. 1 is a plan view illustrating one embodiment of a display device. [Figure 10] FIG. 1 is a cross-sectional view showing one embodiment of a display device. [Figure 11] FIG. 1 is a cross-sectional view showing one embodiment of a display device. [Figure 12] 1A to 1C are diagrams illustrating examples of electronic devices including a semiconductor device. [Figure 13] 1A and 1B are diagrams illustrating an example of a tablet terminal including a semiconductor device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, embodiments of the present invention disclosed in this specification will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and any deviation from the spirit and scope of the present invention is not permitted. It will be easily understood by those skilled in the art that the form and details of the present invention may be modified in various ways. Therefore, the present invention should not be construed as being limited to the description of the following embodiments. .

[0026] In addition, the position, size, range, etc. of each component shown in the drawings are not necessarily shown in order to facilitate understanding. The actual position, size, range, etc. may not be shown. The present invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0027] In this specification, ordinal numbers such as "first," "second," and "third" refer to the number of components. It should be noted that this is added to avoid confusion and is not intended to limit the number.

[0028] In this specification, the terms "above" and "below" refer to the positional relationship of components "directly above" or "below." For example, the term "gate electrode on a gate insulating film" does not necessarily mean "directly under" the gate insulating film. If the expression "gate electrode" is used, it excludes those that include other components between the gate insulating film and the gate electrode. do not.

[0029] In addition, the terms "electrode" and "wiring" used in this specification and the like refer to these components functionally. This is not intended to be limiting. For example, an "electrode" may be used as a part of a "wire." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably to refer to the plural "electrodes" and "wirings." This also includes cases where the wiring is formed integrally.

[0030] In addition, the functions of "source" and "drain" may differ when using transistors with different polarities. In some cases, such as when the direction of the current changes during circuit operation, the two may be interchanged. Therefore, in this specification and the like, the terms "source" and "drain" are used interchangeably. It is assumed that this is possible.

[0031] In this specification, "electrically connected" means "something that has some kind of electrical effect" This includes cases where the device is connected via a "device having some electrical function." "of" is not subject to any particular restrictions as long as it enables the transmission and reception of electrical signals between connected objects. For example, "something that has an electrical effect" includes electrodes, wiring, and transistors. These devices have various functions such as switching elements, resistor elements, inductors, capacitors, etc. This includes elements such as:

[0032] In this specification, patterning refers to using a photolithography process. However, the patterning is not limited to the photolithography process. A process other than the above process can also be used. Also, a mask formed by a photolithography process can be used. shall be removed after the etching process.

[0033] (Embodiment 1) In this embodiment mode, one embodiment of a semiconductor device and a manufacturing method thereof will be described with reference to FIGS. In this embodiment, a transistor using an oxide semiconductor film will be described as an example of a semiconductor device. A transistor is shown.

[0034] <Configuration Example 1 of Semiconductor Device> 1 shows a configuration example of a transistor 150. FIG. 1A is a plan view of the transistor 150. FIG. 1(B) is a cross-sectional view taken along line X1-Y1 of FIG. 1(A), and FIG. 1(C) is a cross-sectional view taken along line X1-Y1 of FIG. 1A is a cross-sectional view taken along the line V1-W1 in FIG. 1A. In order to avoid this, some of the components of the transistor 150 (such as the gate insulating film 106) is omitted in the figure.

[0035] The transistor 150 shown in FIG. 1 includes a gate electrode 104 formed on a substrate 102 and a gate A gate insulating film 106 is formed on the gate electrode 104. The oxide semiconductor film 108 is formed at a position overlapping the electrode 104, and the oxide semiconductor film 10 8, and a source electrode 110 and a drain electrode 112 formed on the semiconductor substrate 100.

[0036] The gate electrode 104 is made up of a first gate electrode 104a and a second gate electrode 104b. The first gate electrode 104a is made of tungsten, tantalum, titanium, and molybdenum. It is preferable that the second gate electrode 104b contains copper. For example, In this embodiment, a tungsten film is used as the first gate electrode 104a, and A copper film is used as the gate electrode 104b of the second gate electrode 104. By doing so, it is possible to obtain a gate electrode 104 with low resistance. By providing the second gate electrode 104a, the substrate 102 and the copper film used as the second gate electrode 104b and / or the copper in the copper film used as the second gate electrode 104b. The diffusion of elements can be suppressed.

[0037] The gate insulating film 106 is made up of a first gate insulating film 106a and a second gate insulating film 10 The first gate insulating film 106a is made up of the second gate electrode 104b. It is sufficient that the silicon nitride film has a function of suppressing the diffusion of copper elements in the copper film used as the silicon nitride film. , a silicon nitride oxide film, an aluminum oxide film, an aluminum nitride oxide film, etc. The second gate insulating film 106b is formed on the oxide semiconductor film 108. The film may be a silicon oxide film, a silicon oxynitride film, etc., as long as it has a function of supplying oxygen to the For example, in this embodiment, the first gate insulating film 106a and A silicon nitride film is used as the second gate insulating film 106b, and a silicon oxynitride film is used as the second gate insulating film 106c. By forming the gate insulating film 106 with such a laminated structure, the gate electrode 104 and The copper film is formed by the oxidation of the oxide semiconductor film 108. Oxygen can be supplied.

[0038] The source electrode 110 includes a first metal film 110a, a second metal film 110b, and a third metal film 110c. The drain electrode 112 is made of a first metal film 112a and a second metal film 110c. The second metal film 112b and the third metal film 112c are also included. The film 110b and the second metal film 112b are the first metal film 110a and the first metal film 112a. , the third metal film 110c, and the third metal film 112c are formed in regions inside the ends of the third metal film 110c and the third metal film 112c. .

[0039] In addition, the first metal film 110a, the first metal film 112a, the third metal film 110c, and The third metal film 112c is selected from the group consisting of tungsten, tantalum, titanium, and molybdenum. It is preferable to use a metal film or a metal nitride film containing one or more elements selected from the above. It is preferable that the second metal film 110b and the second metal film 112b contain copper. .

[0040] For example, in this embodiment, the first metal film 110a and the first metal film 112a A tungsten film is used as the second metal film 110b and a second metal film 112b are used as the second metal film 110c. A copper film is used, and a tantalum nitride film is used as the third metal film 110c and the third metal film 112c. The second metal film 110b and the second metal film 112b are used. a and the first metal film 112a, and a third metal film 110c and a third metal film 11 Covered by 2c.

[0041] That is, the copper film used as the second metal film 110b and the second metal film 112b has a lower surface. The first metal film 110a and the tungsten film used as the first metal film 112a The upper surface and the side surface are covered with the third metal film 110c and the third metal film 112c. The first metal film 110a and the first metal film 112a are covered with a tantalum oxide film. The third metal film 110c and the third metal film 112c suppress the diffusion of copper elements in the copper film. It functions as a barrier metal.

[0042] By using the source electrode 110 and the drain electrode 112 having such a configuration, a low resistance A source electrode 110 and a drain electrode 112 may be provided. and suppressing the diffusion of copper elements from the copper film used in the drain electrode 112 to the outside. It is possible.

[0043] The source electrode 110 and the drain electrode 112 can be formed, for example, by using an oxide semiconductor A first metal film and a second metal film are formed on the film 108, and a first photolithography film is formed on the second metal film. A lithography process is performed, a part of the second metal film is removed by the first etching, and the second metal Then, the first metal film 110b and the second metal film 112b are formed. On the metal film (the second metal film 110b and the second metal film 112b), a metal film is formed so as to cover the second metal film. Then, a second photolithography process is performed on the third metal film. Then, a part of the first metal film and the third metal film is removed by a second etching, and the first metal film is The metal film 110a, the first metal film 112a, the third metal film 110c, and the third metal film 112 By using such a manufacturing method, the copper film used as the second metal film is oxidized. Since the oxide semiconductor film 108 is not directly contacted with the oxide semiconductor film 108, the back This makes it possible to suppress the diffusion of impurities (especially copper elements) that may get mixed into the panel.

[0044] In addition, a first insulating layer of an oxygen-excess type is formed on the source electrode 110 and the drain electrode 112. a first insulating film 114a, a second insulating film 114b formed on the first insulating film 114a, and a second insulating film An aluminum oxide film 116 formed on the insulating film 114b, and The planarization insulating film 118 may be formed on the insulating film 114.

[0045] The details of the other components will be described later with reference to the transistor 150 shown in FIG. The manufacturing method will be described with reference to FIGS.

[0046] <Method 1 for manufacturing semiconductor device> First, a first gate electrode 104a and a second gate electrode 104b are formed on a substrate 102. A gate electrode 104 including the gate electrode 104 is formed (see FIG. 2(A)).

[0047] There is no significant limitation on the substrate that can be used for the substrate 102, but at least the substrate that can be used for the subsequent heat treatment is For example, barium borosilicate Various types of glass used in the electronics industry, such as glass substrates made of glass or aluminoborosilicate glass A glass substrate with a thermal expansion coefficient of 25×10 -7 / ℃ More than 50 x 10 -7 / ℃ or less (preferably 30×10 -7 / ℃ or more 40×10 -7 / ℃ ≦650℃~750℃(preferably 700℃~740℃) It is preferable to use a substrate that is

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

[0049] A semiconductor device may be manufactured using a flexible substrate as the substrate 102. In order to manufacture a semiconductor device having the above structure, a transistor including an oxide semiconductor film 108 is formed on a flexible substrate. The transistor 150 may be directly manufactured, or the transistor including the oxide semiconductor film 108 may be manufactured on another manufacturing substrate. Alternatively, the resistor 150 may be fabricated and then peeled off and transferred to a flexible substrate. A transistor 15 including a formation substrate and an oxide semiconductor film for peeling and transferring to a flexible substrate. It is advisable to provide a release layer between the film and the substrate.

[0050] In addition, a base insulating film may be provided on the substrate 102. The base insulating film may be formed of a plasma CV Silicon oxide, silicon oxynitride, aluminum oxide, etc. are formed by the D method or sputtering method. oxide insulating film such as aluminum oxide nitride, hafnium oxide, gallium oxide, nitride Nitride insulators such as silicon, silicon oxynitride, aluminum nitride, and aluminum oxynitride The membrane may be formed of a material selected from the group consisting of a lamina, a membrane, a coating, a membrane, and a mixture of these materials.

[0051] Alternatively, the substrate 102 may be subjected to a heat treatment. For example, the heat treatment may be performed using a high-temperature gas. 650℃ by GRTA (Gas Rapid Thermal Anneal) equipment The heat treatment is performed for 1 to 5 minutes. An inert gas that does not react with the workpiece during heat treatment, such as a rare gas such as benzene or nitrogen. Alternatively, heat treatment may be performed in an electric furnace at 500°C for 30 minutes to 1 hour. .

[0052] The gate electrode 104 is made of a material selected from the group consisting of tungsten, tantalum, titanium, molybdenum, and copper. The insulating layer 10 can be formed using a material containing one or more selected elements. The second gate electrode 104b is formed by sputtering to a thickness of 100 nm or more and 400 nm or more. A copper film having a thickness of 0 nm or less is formed. In addition, the copper element in the copper film is formed as a lower layer of the second gate electrode 104b. A first gate electrode 104a is formed, which functions as a barrier metal for suppressing element diffusion. In this embodiment, the first gate electrode 104a is formed by sputtering a film. A tantalum nitride film having a thickness of 20 nm to 100 nm is formed.

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

[0054] Next, a first gate insulating film 106a and a second gate insulating film 106b are formed on the substrate 102 and the gate electrode 104. The gate insulating film 106 including the gate insulating film 106b is formed (see FIG. 2B).

[0055] The first gate insulating film 106a is formed by plasma CVD or sputtering. The thickness of the film to be formed is 10 nm to 100 nm, more preferably 20 nm to 50 nm. It is preferable to use the following nitride insulating film. For example, silicon nitride film, silicon oxynitride film, The first gate insulating film 1 in contact with the substrate 102 and the gate electrode 104 is a By using a nitride insulating film as 06a, the insulating film 106a is formed on the substrate 102 or the gate electrode 104. This has the effect of suppressing the diffusion of impurities. When a metal material containing copper is used for the first gate electrode 104b, the first gate insulating film 106a Accordingly, diffusion of the copper element into the oxide semiconductor film 108 can be suppressed.

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

[0057] The second gate insulating film 106b is formed by plasma CVD or sputtering. The thickness of the film to be formed is 100 nm or more and 350 nm or less, and more preferably 100 nm or more and 200 nm or less. It is preferable to use an oxide insulating film having a thickness of 100 μm or less. For example, a silicon oxide film or a gallium oxide film is used. Examples of the film include an aluminum oxide film, a silicon oxynitride film, and an aluminum oxynitride film. do.

[0058] The second gate insulating film 106b is made of hafnium oxide, yttrium oxide, or the like. , hafnium silicate (HfSi x O y (x>0, y>0)), nitrogen doped Huff HfSiO x N y (x>0, y>0)), hafnium aluminate ( HfAl x O y (x>0, y>0)) and using high-k materials such as lanthanum oxide. This can reduce the gate leakage current.

[0059] In this embodiment, the second gate insulating film 106b is formed by a plasma CVD method. A 200 nm silicon oxynitride film is formed. The plasma CVD method is different from the sputtering method. In comparison, the deposition time can be reduced. The film thickness variation on the surface is smaller than that of the coating method, and there is no possibility of particles being mixed in. Hard.

[0060] Note that the second gate insulating film 106b is an insulating film in contact with the oxide semiconductor film 108. Therefore, it is preferable to use an insulating film that contains oxygen, and impurities such as water and hydrogen should be avoided as much as possible. However, in the plasma CVD method, as compared with the sputtering method, Therefore, it is difficult to reduce the hydrogen concentration in the film. The insulating film 106b is subjected to a heat treatment (dehydration) for the purpose of reducing, and more preferably removing, hydrogen atoms. Hydrogenation or dehydrogenation treatment may be performed.

[0061] The temperature of the heat treatment is 250°C or higher and 650°C or lower, preferably 450°C or higher and 600°C or lower. For example, the substrate is introduced into an electric furnace, which is one type of heat treatment device. The gate insulating film 106 is then subjected to a heat treatment at 650° C. for 1 hour in a vacuum (reduced pressure) atmosphere. Carry out the analysis.

[0062] The heat treatment device is not limited to an electric furnace, and may be a heat treatment device that uses heat conduction or heat from a heating element such as a resistance heating element. A device that heats the workpiece by radiation may be used. For example, a GRTA (Gas Reactor Transformer) apid Thermal Anneal) equipment, LRTA (Lamp Rapid T RTA (Rapid Thermal Anneal) equipment, etc. al) equipment can be used. The LRTA equipment can be a halogen lamp, a metal halide lamp, lamp, xenon arc lamp, carbon arc lamp, high pressure sodium lamp, high pressure mercury lamp This is a device that heats the workpiece by radiating light (electromagnetic waves) emitted from a lamp or other light source. The GRTA device is a device that performs heat treatment using high-temperature gas. An inert gas that does not react with the workpiece during heat treatment, such as a rare gas such as argon or nitrogen. When a GRTA device is used as the heat treatment device, Since the time is short, the substrate may be heated in an inert gas at a high temperature of 650°C to 700°C. stomach.

[0063] The heat treatment is carried out in a nitrogen, oxygen or ultra-dry air (water content less than 20 ppm, preferably less than 1 ppm). m or less, more preferably 10 ppb or less of air), or rare gases (argon, helium The above-mentioned atmospheres of nitrogen, oxygen, ultra-dry air, rare gas, etc. may be used. It is preferable that the gas does not contain water, hydrogen, etc. The purity of the nitrogen or rare gas should be 6N (99.9999%) or more, preferably 7N (99.99 999%) or more (i.e., impurity concentration is 1 ppm or less, preferably 0.1 ppm or less). It is preferable.

[0064] The heat treatment can dehydrate or dehydrogenate the gate insulating film 106. A gate insulating film that is free of impurities such as hydrogen or water that can cause transistor characteristic fluctuations. 106 can be formed.

[0065] The heat treatment for dehydration or dehydrogenation may be carried out multiple times or in combination with other heat treatments. You can sleep.

[0066] Next, an oxide semiconductor film is formed on the gate insulating film 106 at a position where the oxide semiconductor film is in contact with the gate insulating film 106 and overlaps with the gate electrode 104. 108 is formed (see FIG. 2(C)).

[0067] The oxide semiconductor film 108 may have a single-layer structure or a stacked-layer structure. The oxide semiconductor film 108 may have an amorphous structure or may be crystalline. In the case where the oxide semiconductor film 108 is to be formed as the second insulating film, heat treatment is performed on the oxide semiconductor film 108 in a later manufacturing process. The amorphous oxide semiconductor film may be crystallized. The temperature of the heat treatment is 250° C. or more and 700° C. or less, preferably 400° C. or more, and more preferably The heat treatment is preferably performed at 500°C or higher, more preferably at 550°C or higher. It is also possible to combine this step with other heat treatments.

[0068] The oxide semiconductor film 108 is formed by a sputtering method, an MBE (Molecular Beam Induction) method, or the like. Beam Epitaxy, Plasma CVD, Pulsed Laser Deposition, ALD (A A method such as atomic layer deposition (ALD) method can be used as appropriate.

[0069] When the oxide semiconductor film 108 is formed, hydrogen contained in the oxide semiconductor film 108 is reduced as much as possible. It is preferable to reduce the hydrogen concentration. For example, sputtering can be used to reduce the hydrogen concentration. When a film is formed by the sputtering method, the atmospheric gas supplied to the processing chamber of the sputtering device is The rare gas is a high-purity gas from which impurities such as hydrogen, water, hydroxyl groups, and hydrides have been removed (typically For the gas, argon, oxygen, and a mixture of a rare gas and oxygen are appropriately used.

[0070] In addition, the sputtering gas from which hydrogen and water have been removed is used while removing the residual moisture in the processing chamber. By introducing hydrogen into the oxide semiconductor film 108, the hydrogen concentration in the oxide semiconductor film 108 can be reduced. In order to remove the residual moisture in the processing chamber, an adsorption type vacuum pump, e.g. It is preferable to use a lion pump, an ion pump, or a titanium sublimation pump. Alternatively, a turbo molecular pump with a cold trap may be used. The group is, for example, a hydrogen molecule, water (H2O), or other compounds containing hydrogen atoms (more preferably carbon The pumping capacity of the cryopump is high, so the processing chamber is evacuated using the cryopump. Therefore, the concentration of impurities in the oxide semiconductor film 108 formed by the above method can be reduced.

[0071] In this embodiment, the oxide semiconductor film 108 is made of a compound semiconductor having an atomic ratio of In:Ga:Zn. Metal oxide target with an atomic ratio of In:Ga=1:1:1, or a metal oxide target with an atomic ratio of In:Ga=2:1 The oxide semiconductor film 108 is formed by a sputtering method using an oxide semiconductor target. The targets that can be used are limited to these target materials and compositions. The oxide semiconductor film 108 is heated under a rare gas (typically, argon) atmosphere. Formed by sputtering in an oxygen atmosphere or a mixture of rare gas and oxygen. In addition, a target that can be used for the oxide semiconductor film 108 is A target having crystallinity such as a crystal or polycrystal is preferred. As a result, the thin film formed also has crystallinity, and in particular, the c-axis The crystals tend to be oriented in the direction.

[0072] In addition, the oxide semiconductor film 108 has a higher oxygen content than the stoichiometric composition immediately after deposition. For example, the oxide semiconductor film 1 is formed by sputtering. When forming a film of 08, it is preferable to form the film under conditions in which the proportion of oxygen in the film forming gas is high. It is particularly preferable to form the film in an oxygen atmosphere (100% oxygen gas). The conductive film 108 is made of In-Ga-Zn oxide (IGZO), and the oxygen in the film-forming gas is When the film is formed under conditions where the proportion of oxygen is high (especially in an atmosphere of 100% oxygen gas), the film formation temperature is increased to 30 Even at temperatures above 0° C., the release of Zn from the film is suppressed.

[0073] The oxide semiconductor film 108 is made of the above-mentioned gold alloy having an atomic ratio of In:Ga:Zn=1:1:1. When a metal oxide target is used, the composition of the target and the thickness of the thin film formed on the substrate are important factors. The composition of the film may be different. For example, metal oxide with In:Ga:Zn=1:1:1 When a target is used, the oxide semiconductor film 108 is a thin film, although this depends on the film formation conditions. The composition may be In:Ga:Zn=1:1:0.6-0.8 in terms of atomic ratio. During the formation of the oxide semiconductor film 108, Zn is sublimated, or In, Ga, Zn This is thought to be because the sputtering rates of each component are different.

[0074] Therefore, when it is desired to form a thin film of a desired composition, a metal oxide target is first prepared. For example, the composition of the oxide semiconductor film 108, which is a thin film, needs to be adjusted. When the molecular ratio is In:Ga:Zn=1:1:1, the metal oxide target The composition should be In:Ga:Zn=1:1:1.5 in atomic ratio. However, the composition of the target should be: The values ​​are not limited to the above values, and can be appropriately adjusted depending on the film formation conditions and the composition of the thin film to be formed. In addition, by increasing the Zn content of the metal oxide target, the obtained thin This is preferable because it improves the crystallinity of the film.

[0075] In addition, when the oxide semiconductor film 108 is formed by a sputtering method, The relative density of the oxide target is 90% or more and 100% or less, preferably 95% or more, and more preferably The relative density is preferably 99.9% or more. By using a metal oxide target with a high relative density, Thus, the oxide semiconductor film 108 can be formed as a dense film.

[0076] In addition, the oxide semiconductor film 108 can be formed while the substrate 102 is kept at a high temperature. This is effective in reducing the concentration of impurities that may be contained in the oxide semiconductor film 108. The heating temperature may be 150°C or higher and 450°C or lower, and preferably 170°C or higher. The upper limit is 350° C. or less. In addition, by heating the substrate at a high temperature during film formation, the crystalline oxide A compound semiconductor film 108 can be formed.

[0077] The oxide semiconductor used for the oxide semiconductor film 108 is at least indium (In). Alternatively, it is preferable that the alloy contains zinc (Zn). In particular, it is preferable that the alloy contains both In and Zn. In addition, a transistor using the oxide semiconductor can be formed by a semiconductor laser. It is preferable to have gallium (Ga) in addition to the above as a stabilizer. It is preferable to have tin (Sn) as a stabilizer. It is preferable to use hafnium (Hf) as a stabilizer. It is preferable that the alloy contains aluminum (Al) as a stabilizer. It is preferred that the compound has the formula:

[0078] Other stabilizers include the lanthanides lanthanum (La) and cerium. (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium Eu, Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Luminium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), It may contain one or more of lutetium (Lu).

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

[0080] In addition, for example, In-Ga-Zn oxide is a material containing In, Ga, and Zn as main components. The ratio of In, Ga, and Zn does not matter. Metal elements other than Ga and Zn may be included.

[0081] In addition, as an oxide semiconductor, InMO3(ZnO) m (m>0 and m is not an integer In addition, M is selected from Ga, Fe, Mn, and Co. The metal element or elements are also shown. In2SnO 5(ZnO) n A material expressed as (n>0, and n is an integer) may be used.

[0082] For example, In:Ga:Zn=1:1:1 (=1 / 3:1 / 3:1 / 3), In:Ga: Zn=2:2:1 (=2 / 5:2 / 5:1 / 5), or In:Ga:Zn=3:1: In-Ga-Zn oxide with an atomic ratio of 2 (=1 / 2:1 / 6:1 / 3) and its close composition Alternatively, the oxide of In:Sn:Zn=1:1:1 (=1 / 3) can be used. :1 / 3:1 / 3), In:Sn:Zn=2:1:3(=1 / 3:1 / 6:1 / 2) In-S with an atomic ratio of In:Sn:Zn=2:1:5 (=1 / 4:1 / 8:5 / 8) It is advisable to use n-Zn oxide or an oxide having a composition close to that.

[0083] However, it is not limited to these, and the required semiconductor characteristics (mobility, threshold, variation, etc.) In order to obtain the required semiconductor characteristics, Carrier concentration, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. It is preferable to make the following appropriate.

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

[0085] For example, the atomic ratio of In, Ga, and Zn is In:Ga:Zn=a:b:c(a+b +c=1), the atomic ratio of the oxide is In:Ga:Zn=A:B:C (A+B+ C=1) is close to the oxide composition when a, b, and c are (aA) 2 +(bB) 2 +(cC) 2 ≦r 2 It means that the following is satisfied. For example, r can be set to 0.05. The same is true for other oxides.

[0086] The oxide semiconductor film 108 is a CAAC-OS (C Axis Aligned C The preferred film is a crystalline oxide semiconductor (Crystalline Oxide Semiconductor) film. It is.

[0087] The CAAC-OS film is neither completely single crystalline nor completely amorphous. The film is an oxide semiconductor layer having a crystalline-amorphous mixed phase structure in which a crystalline portion is included in an amorphous phase. The crystal part is often small enough to fit inside a cube with one side less than 100 nm. , Transmission Electron Microscopy (TEM) In the observation image by a microscope, the boundary between the amorphous part and the crystalline part in the CAAC-OS film was In addition, grain boundaries were not clearly observed in the CAAC-OS film by TEM. Therefore, the CAAC-OS film does not show any electron transfer due to grain boundaries. The decrease in mobility is suppressed.

[0088] The crystal parts in the CAAC-OS film have c-axes that are normal vectors to the surface on which the CAAC-OS film is formed. The three are aligned parallel to the normal vector of the torus or surface and perpendicular to the ab plane. It has a square or hexagonal atomic arrangement, and the metal atoms are arranged in layers or in a layered fashion when viewed perpendicular to the c-axis. In the crystal structure, metal atoms and oxygen atoms are arranged in layers. The direction of the a and b axes may be different. In this specification, when it is simply described as being vertical, The range of 85° to 95° is also included. The range of 5° or more and 5° or less is also included.

[0089] In the CAAC-OS film, the distribution of the crystal parts may not be uniform. In the process of forming the AC-OS film, when crystal growth is performed from the surface side of the oxide semiconductor film, The proportion of crystalline parts may be higher near the surface than near the formation surface. By adding impurities to the AAC-OS film, the crystal part becomes non-crystalline in the impurity-added region. It may also crystallize.

[0090] The c-axis of the crystal part in the CAAC-OS film is the normal vector of the surface on which the CAAC-OS film is formed. The shape of the CAAC-OS film (the shape of the film) is Depending on the cross-sectional shape of the mating surface or the cross-sectional shape of the surface, they may face in different directions. The direction of the c-axis of the crystal part is the normal vector of the surface on which the CAAC-OS film is formed. The direction of the crystal is parallel to the normal vector of the crystal or the surface. Alternatively, it is formed by carrying out a crystallization treatment such as a heat treatment after the film formation.

[0091] The electrical characteristics of transistors using CAAC-OS films change when irradiated with visible or ultraviolet light. Therefore, the transistor has high reliability.

[0092] In the case where a CAAC-OS film is used as the oxide semiconductor film 108, the CAAC-OS film There are three ways to achieve this. The first is to set the film formation temperature at 100°C or higher and 450°C or lower. and more preferably, the oxide semiconductor layer is formed at a temperature of 150° C. or higher and 400° C. or lower. The second method is to form a thin oxide semiconductor layer with a c-axis orientation that is roughly vertical. Then, heat treatment is performed at 200°C to 700°C to orient the c-axis approximately perpendicular to the surface. The third method is to form a thin film as the first layer, and then heat treat it at a temperature between 200℃ and 700℃. This method involves first treating the surface and then depositing a second layer, and then aligning the c-axis approximately perpendicular to the surface.

[0093] Note that as the oxide semiconductor film 108, an oxide semiconductor film having crystallinity other than a CAAC-OS film may be used. When a conductor film (single crystal or microcrystalline) is formed, the film formation temperature is not particularly limited.

[0094] The oxide semiconductor film 108 has an energy gap of 2.8 eV to 3.2 eV. The energy gap of the oxide semiconductor film is 1.1 eV, which is larger than that of silicon. The intrinsic carrier density of 108 is 10 -9 cm -3 and the intrinsic carrier density of silicon is 10 11 cm -3 is extremely small compared to

[0095] The majority carriers (electrons) in the oxide semiconductor film 108 flow from the source of the transistor. In addition, the channel formation region can be completely depleted, so the transistor The off-state current of the transistor using the oxide semiconductor film 108 can be made extremely small. The off-state current of the transistor is 10yA / μm or less at room temperature, and at 85℃ to 95℃ , which is extremely small, less than 1zA / μm.

[0096] The oxide semiconductor film 108 may have a structure in which a plurality of oxide semiconductor layers are stacked. For example, the oxide semiconductor film 108 may be a stack of a first oxide semiconductor layer and a second oxide semiconductor layer. The first oxide semiconductor layer and the second oxide semiconductor layer are formed of metal oxides having different compositions. For example, a ternary metal oxide may be used for the first oxide semiconductor layer, and a second oxide semiconductor may be used for the second oxide semiconductor layer. The conductor layer may be made of a binary metal oxide. Both of the semiconductor layers may be oxides of ternary metals.

[0097] In addition, the first oxide semiconductor layer and the second oxide semiconductor layer are made to contain the same elements. For example, the atomic ratio of the first oxide semiconductor layer may be set to In:Ga:Zn= The atomic ratio of the second oxide semiconductor layer is In:Ga:Zn=3:1:2. The atomic ratio of the first oxide semiconductor layer may be In:Ga:Zn=1:3:2. The atomic ratio of the second oxide semiconductor layer may be In:Ga:Zn=2:1:3.

[0098] At this time, the first oxide semiconductor layer or the second oxide semiconductor layer closer to the gate electrode ( The In and Ga contents of the oxide semiconductor layer on the channel side are preferably In>Ga. The In and Ga contents of the oxide semiconductor layer on the side farther from the gate electrode (back channel side) are set to In. In oxide semiconductors, the s orbitals of heavy metals mainly contribute to carrier conduction. Increasing the In content tends to increase the overlap of s orbitals. Therefore, oxides with a composition of In>Ga have a higher thermal conductivity than oxides with a composition of In≦Ga. In addition, the formation energy of oxygen vacancies in Ga is larger than that in In, and the formation of oxygen vacancies in Ga is smaller than that in In. Therefore, oxides with a composition of In≦Ga are less likely to cause loss than oxides with a composition of In>Ga. Therefore, the oxide layer with a composition of In>Ga on the channel side is A semiconductor layer with a composition of In≦Ga is applied to the back channel side. By doing so, it is possible to further increase the mobility and reliability of the transistor.

[0099] In addition, when the oxide semiconductor film 108 is stacked, the first oxide semiconductor layer and the second oxide semiconductor layer The conductor layer may be made of oxide semiconductors with different crystallinity. A semiconductor having a crystallinity, a polycrystalline oxide semiconductor, an amorphous oxide semiconductor, or an oxide semiconductor having a crystallinity (e.g. For example, a structure in which CAAC-OS is appropriately combined may be used. At least one of the first oxide semiconductor layer and the second oxide semiconductor layer is made of an amorphous oxide semiconductor. This reduces the internal and external stress of the oxide semiconductor, reducing the variation in transistor characteristics. This reduces the amount of oxide that can be deposited on the surface of the transistor, which makes it possible to further improve the reliability of the transistor. Semiconductors are prone to absorbing impurities such as hydrogen, which act as donors, and are prone to oxygen vacancies. Therefore, the oxide semiconductor layer on the channel side is easily converted to n-type. It is preferable to use an oxide semiconductor (eg, CAAC-OS).

[0100] In addition, the combination of the composition and the crystallinity in the case where the oxide semiconductor film 108 is stacked is For example, in order from the gate insulating film 106 side, the number of atoms in the vicinity of In:Ga:Zn=1:1:1 The amorphous oxide semiconductor layer has an atomic ratio of In:Ga:Zn=3:1:2. Layered structure with a Zn-based semiconductor layer, or crystallinity with an atomic ratio of In:Ga:Zn=1:1:1 An oxide semiconductor layer and a crystalline oxide semiconductor having an atomic ratio of In:Ga:Zn=3:1:2 or so. Another example of a layered structure is In:Ga:Zn=3 A crystalline oxide semiconductor layer having an atomic ratio of about In:Ga:Zn=1:1:1 and a crystalline oxide semiconductor layer having an atomic ratio of about In:Ga:Zn=1:1:1. A stacked structure with a crystalline oxide semiconductor layer may be used. An amorphous oxide semiconductor layer having an atomic ratio of about In:Ga:Zn=1:1:1 and In:Ga: A stacked structure with an amorphous oxide semiconductor layer having an atomic ratio of about Zn=3:1:2, or In:Ga and an amorphous oxide semiconductor layer having an atomic ratio of about In:Ga:Zn=1: A stacked structure with an amorphous oxide semiconductor layer having an atomic ratio of approximately 1:1 may also be used.

[0101] In addition, before the oxide semiconductor film 108 is formed, a planarization treatment is performed on the surface on which the oxide semiconductor film 108 is to be formed. The planarization process may be, but is not limited to, a polishing process (e.g., chemical polishing). Chemical Mechanical Polishing (CMP) A vacuum etching process, a dry etching process, and a plasma process can be used.

[0102] The plasma treatment may be, for example, a reverse plasma treatment in which argon gas is introduced to generate plasma. Reverse sputtering is a process in which R is applied to the substrate side in an argon atmosphere. This is a method of modifying the surface by applying voltage using an F power source to generate plasma near the substrate. In place of argon, nitrogen, helium, oxygen, etc. may be used. When the above-mentioned process is performed, powdery substances (particles, etc.) attached to the deposition surface of the oxide semiconductor film 108 are removed. It is possible to remove the

[0103] As flattening processes, polishing, dry etching, and plasma treatment can be performed multiple times. In addition, when the steps are combined, the order of the steps is not particularly limited. There are no limitations and may be appropriately set depending on the unevenness of the surface on which the oxide semiconductor film 108 is to be formed. .

[0104] In addition, after the oxide semiconductor film 108 is formed, excess water contained in the oxide semiconductor film 108 is Heat treatment to reduce or remove (dehydrate or dehydrogenate) hydrogen (including water and hydroxyl groups) The heat treatment conditions are the same as those for the second gate insulating film 106b. The heat treatment can be carried out under the same conditions as those for the heat treatment carried out in the above-mentioned step.

[0105] By this heat treatment, impurities that impart n-type conductivity, The hydrogen can be reduced, more preferably removed. When an insulating film containing oxygen is used as the second gate insulating film 106b, the second gate insulating film 106b is heated by this heat treatment. The oxygen contained in the oxide semiconductor film 108 is supplied to the oxide semiconductor film 108. Alternatively, oxygen that is simultaneously desorbed during the dehydrogenation process is supplied from the second gate insulating film 106b. By this, oxygen vacancies in the oxide semiconductor film 108 can be filled.

[0106] After the oxide semiconductor film 108 is heated by the heat treatment, the heating temperature is maintained or the heating temperature is changed. While slowly cooling from the temperature, high purity oxygen gas, high purity dinitrogen monoxide gas, or ultra pure oxygen gas are added to the same furnace. Dry air (measured using a CRDS (Cavity Ring Down Laser Spectroscopy) type dew point meter) When the moisture content is measured, it should be 20 ppm or less (-55°C in terms of dew point), preferably 1 ppm or less. , more preferably air of 10 ppb or less) may be introduced. Oxygen gas or nitrous oxide It is preferable that the oxygen gas does not contain water, hydrogen, etc. The purity of the nitrogen gas or dinitrogen monoxide gas is 6N or more, preferably 7N or more (i.e., oxygen gas). Or the impurity concentration in the nitrous oxide gas is 1 ppm or less, preferably 0.1 ppm or less. It is preferable that the action of oxygen gas or nitrous oxide gas is used to dehydrate or decompose the The oxide semiconductor film 10 was reduced during the impurity removal process by hydrogenation. By supplying oxygen, which is a main component material of the oxide semiconductor film 108, the oxide semiconductor film 108 is heated. It can be purified and made into type i (true).

[0107] The heat treatment for dehydration or dehydrogenation is the same as other heat treatments in the fabrication process of the transistor 150. This may also be used in conjunction with the above.

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

[0109] The first metal film 109a is made of tungsten, tantalum, titanium, or molybdenum. It is preferable that the metal film contains one or more elements selected from the above, or a metal nitride film. In the embodiment, the first metal film 109a is formed by using a sputtering method. A tungsten film having a thickness of 50 nm is used.

[0110] The first metal film 109a may have a laminated structure. For example, the first metal film 109a The first layer is selected from tungsten, tantalum, titanium, and molybdenum. The metal film contains one or more elements, and the second layer of the first metal film 109a is made of tungsten nitride. One or more elements selected from the group consisting of tantalum nitride, titanium nitride, and molybdenum nitride are added to the and a laminated structure of a metal nitride film containing the metal nitride.

[0111] The first metal film 109a is in contact with the oxide semiconductor film 108. A material that does not extract oxygen from the oxide semiconductor film 108 to become n-type, or a material that diffuses into the oxide semiconductor film 108 to become n-type The first metal film 109a is made of a material that does not cause the metal to be broken. A material that suppresses the diffusion of copper elements from the copper film to the oxide semiconductor film 108 (so-called barrier metal material) It is preferable to use the following:

[0112] The second metal film 109b is preferably a film containing copper. Alternatively, a copper alloy containing a few weight percent of aluminum, gold, silver, zinc, tin, nickel, or the like may be used. In this embodiment, the second metal film 109b is formed by using a sputtering method. A copper film having a thickness of 200 nm is used.

[0113] Next, a resist is applied onto the second metal film 109b, and a first patterning is performed. A mask 141 is formed (see FIG. 2(E)).

[0114] The resist mask 141 is formed by applying a photosensitive resin, exposing the photosensitive resin to light, and The photosensitive resin can be either positive or negative. Alternatively, the resist mask 141 may be formed by an ink-jet method. If the resist mask 141 is formed by the inkjet method, a photomask is not used. This reduces manufacturing costs.

[0115] Next, a part of the second metal film 109b is removed by a first etching process, and the second metal film 1 Then, a first metal film 10b and a second metal film 112b are formed (see FIG. 3(A)).

[0116] The second metal film 109b is preferably removed by wet etching. The chemical used in the wet etching method is the same as that used to etch the second metal film 109b. Any chemical solution that can remove the first metal film 109a and does not cause the first metal film 109a to disappear may be used. For example, A tungsten film is used as the first metal film 109a, and a copper film is used as the second metal film 109b. In this case, the chemical solution is a mixture of water, hydrogen peroxide, and carboxylic acid, or water, phosphoric acid, and nitric acid. A mixture of sulfuric acid and potassium sulfate can be used.

[0117] In addition, the wet etching time is adjusted to perform isotropic etching, and the resist mask is removed. The second metal film 110b and the side surface of the second metal film 112b are disposed on the inner side of the side surface of the ridge 141. It may also be in a recessed shape.

[0118] Next, the resist mask 141 is removed (see FIG. 3B).

[0119] The resist mask 141 can be removed by a wet method using a stripping solution or a plasma method. Use dry removal methods such as plasma processing, or a combination of these methods. It is possible.

[0120] Next, on the first metal film 109a, the second metal film 110b, and the second metal film 112b, Then, a third metal film 109c is formed (see FIG. 3(C)).

[0121] The third metal film 109c is formed by the same method and material as the first metal film 109a. In this embodiment, the third metal film 109c can be formed as follows. A tantalum nitride film having a thickness of 100 nm formed by sputtering is used.

[0122] Next, a resist is applied onto the third metal film 109c, and a second patterning is performed. A mask 142 is formed (see FIG. 3(D)).

[0123] The resist mask 142 is formed using the same material and method as the resist mask 141. It is possible.

[0124] Next, the first metal film 109a and a part of the third metal film 109c are subjected to a second etching. The first metal film 110a, the first metal film 112a, the third metal film 110c, and Then, a third metal film 112c is formed (see FIG. 4(A)).

[0125] The second etching is performed to remove the second metal film 110b removed by the first etching. , and on the outside of the end of the second metal film 112b, the first metal film 109a and the third metal film Remove 109c.

[0126] The first metal film 109a and the third metal film 109c are removed by dry etching. The gas used in the dry etching method is, for example, A tungsten film is used as the first metal film 109a, and a tungsten nitride film is used as the third metal film 109c. When using a quartz film, a mixture of SF6 and O2, or a mixture of SF6 and BCl3, etc. It can be used.

[0127] In addition, when the first metal film 109a and the third metal film 109c are etched, oxide The etching conditions are optimized so that the semiconductor film 108 is etched without being divided. However, it is desirable that only the first metal film 109a and the third metal film 109c are It is possible to obtain a condition in which the oxide semiconductor film 108 is not etched at all. It is difficult to etch the first metal film 109a and the third metal film 109c, because the oxide semiconductor The conductive film 108 is partially etched to form an oxide semiconductor film 108 having a groove (a recess). This can sometimes happen.

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

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

[0130] The method for removing the resist mask 142 is the same as the method for removing the resist mask 141. This can be done in a similar manner.

[0131] After the source electrode 110 and the drain electrode 112 are formed, the oxide semiconductor film 108 ( More specifically, it is preferable to clean the back channel side of the oxide semiconductor film 108. The cleaning may be performed, for example, by oxygen plasma treatment or by cleaning with dilute hydrofluoric acid. By carrying out such cleaning, the source electrode 110 and the drain Components of the etching gas used in forming the inner electrode 112 or residues of the resist mask 142 and the like can be removed from the oxide semiconductor film 108, It can be made into

[0132] After the source electrode 110 and the drain electrode 112 are formed, a heat treatment may be performed. The temperature of the heat treatment is 250° C. or higher and 650° C. or lower, preferably 450° C. or higher and 600° C. or lower. , or below the distortion point of the substrate.

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

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

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

[0136] The first insulating film 114a is preferably an oxygen-excess oxide insulating film. By using a nitrogen-rich oxide insulating film, oxygen can be suitably supplied to the oxide semiconductor film 108. This can be done.

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

[0138] Oxygen 145 includes at least oxygen radicals, ozone, oxygen atoms, and oxygen ions (atoms). The ions include either the ions themselves, or cluster ions.

[0139] The introduction of oxygen 145 into the first insulating film 114a can be performed by, for example, ion implantation or ion doping. using the plasma immersion ion implantation method, plasma treatment, etc. It should be noted that a gas cluster ion beam may be used as the ion implantation method. The oxygen 145 may be introduced to the entire surface of the first insulating film 114a at once. For example, a linear ion beam may be used. When a linear ion beam is used, the substrate Alternatively, the ion beam is moved (scanned) relatively to the first insulating film 114a. Oxygen 145 can be introduced to the surface.

[0140] As the supply gas of oxygen 145, a gas containing O may be used, for example, O2 gas. , N2O gas, CO2 gas, CO gas, NO2 gas, etc. can be used. The supply gas may contain a rare gas (eg, Ar).

[0141] Also, for example, when oxygen is introduced by ion implantation, the dose of oxygen 145 is 1×1 0 13 ions / cm 2 5×10 or more 16 ions / cm 2 It is preferable that the acid The oxygen content in the first insulating film 114a after the oxygen introduction process is determined by the chemical It is preferable to have the oxygen implantation depth exceed the stoichiometric composition. It is sufficient to control it appropriately.

[0142] The first insulating film 114a is an oxide insulating film (for example, a silicon oxide film or a nitride oxide film). When a silicon oxide film is used, oxygen is one of the main components of the oxide insulating film. For this reason, the oxygen concentration in the oxide insulating film is measured by SIMS (Secondary Ion Measuring It is difficult to estimate accurately using methods such as mass spectrometry. In other words, it is difficult to determine whether oxygen has been intentionally added to the oxide insulating film. In addition, excess oxygen contained in the first insulating film 114a may be converted into an oxide semiconductor in a later step. The same is true when it is supplied to the conductive film 108.

[0143] By the way, oxygen has 17 O and 18 There are isotopes such as O, and these Their abundance ratios are known to be approximately 0.038% and 0.2% of all oxygen atoms, respectively. That is, in the insulating film in contact with the oxide semiconductor film (in this embodiment, the first insulating film 114a) or the concentrations of these isotopes in the oxide semiconductor film can be measured using methods such as SIMS. Therefore, by measuring these concentrations, the oxide To estimate the oxygen concentration in an insulating film in contact with a semiconductor film or in an oxide semiconductor film more accurately. Therefore, by measuring the concentrations of these, it is possible to determine whether the oxide semiconductor film is in contact with the oxide semiconductor film. Alternatively, it may be possible to determine whether or not oxygen has been added to the insulating film.

[0144] In this manner, the introduction of oxygen 145 forms an oxygen-excess first insulating film 114a. By using the oxygen-excess first insulating film 114a, the heat treatment in the transistor manufacturing process can be performed without causing any problem. Oxygen can be supplied to the oxide semiconductor film 108 by solid-phase diffusion caused by the above-mentioned phenomenon. In addition, the introduction of oxygen 145 causes the oxide semiconductor Oxygen may be introduced into the film 108 .

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

[0146] The second insulating film 114b is formed by a plasma CVD method or a sputtering method. Silicon oxide film, gallium oxide film, aluminum oxide film, silicon nitride film, A silicon oxynitride film, an aluminum oxynitride film, or a silicon nitride oxide film is used. The thickness of the second insulating film 114b is preferably set to 50 nm or more and 500 nm or less. It is.

[0147] In this embodiment, the second insulating film 114b is a 370 nm thick film formed by plasma CVD. The second insulating film 114b is formed under the following conditions: The gas flow ratio of SiH4 to N2O was set to 30sccm:4000sccm, and the pressure The pressure was set to 200 Pa, the RF power supply power (power output) to 150 W, and the substrate temperature to 220°C ± 15℃ would be fine.

[0148] When the first insulating film 114a and the second insulating film 114b are made of the same material, In some cases, the interface between the first insulating film 114a and the second insulating film 114b is not clearly defined. Therefore, in this embodiment, the first insulating film 114a and the second insulating film 114b The interface with the substrate is indicated by a dashed line.

[0149] The second insulating film 114b is preferably free of water, hydrogen, etc., as is the first insulating film 114a. It is preferable that the impurities are not contained. The second insulating film 114b is subjected to a heat treatment (dehydration or dehydration) for the purpose of removing hydrogen atoms. The metal is then subjected to a metallurgical treatment.

[0150] The temperature of the heat treatment is, for example, 250° C. or higher and 600° C. or lower, preferably 300° C. or higher and 600° C. or lower. C. or less. In this embodiment, the heat treatment is performed at 350.degree. C. for 1 hour.

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

[0152] The aluminum film 115 can be formed by a sputtering method, a vapor deposition method, a CVD method, or the like. It is preferable that the thickness of the aluminum film 115 is set to 3 nm or more and 10 nm or less. In this embodiment, a 5 nm-thick aluminum film is formed by sputtering. A film is formed.

[0153] The aluminum film 115 formed on the second insulating film 114b is to be treated by oxygen introduction later. This process results in an aluminum oxide film, which functions as a barrier film for transistors. The aluminum oxide film is a film that prevents impurities such as hydrogen and water from entering the transistor, and The membrane has a high blocking effect (blocking effect) that prevents both water and oxygen from passing through it. It has a nature.

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

[0155] Oxygen 147 can be introduced in the same manner as oxygen 145.

[0156] Furthermore, the introduction of oxygen 147 causes the second insulating film 114b to be in contact with the aluminum film 115. Oxygen may be introduced into a part of the film. This allows the second insulating film 114b to have the same structure as the above. This compensates for the oxygen that may be desorbed by heat treatment and increases the amount of oxygen in the alloy compared to the stoichiometric composition. It is possible to form a region containing an excess of such an acid exceeding the stoichiometric composition. The region containing oxygen may be present in a part of the second insulating film 114b. The depth may be appropriately controlled by the implantation conditions.

[0157] In addition, the aluminum oxide film 116 also has a region containing oxygen exceeding the stoichiometric composition. However, the aluminum oxide film 116 formed by the oxygen introduction process is It does not need to contain stoichiometric oxygen and may have some electrical conductivity. For example, the composition is AlO x In the case of an aluminum oxide film represented by the formula: x is 1 to 3.5. In addition, when the aluminum oxide film 116 has conductivity, Resistivity ρ, 10 10 Ω m or more 10 19 Ω·m or less, preferably 10 10 Ω m or more 1 0 18 Ω·m or less, preferably 10 11 Ω m or more 10 15 Ω·m or less It is preferable that the aluminum oxide film 116 has a resistivity in the above range. This makes it possible to prevent electrostatic damage to the capacitor 150.

[0158] The aluminum oxide film 116 is formed by oxidizing the aluminum film 115. The aluminum film 115 is oxidized to form an aluminum oxide film 116. By forming an aluminum oxide film, the thickness of the film is reduced compared to the case of forming an aluminum oxide film by sputtering. This can improve productivity.

[0159] After the oxygen 147 is introduced into the aluminum film 115, a heat treatment may be performed. The oxygen contained in the first insulating film 114a or the second insulating film 114b is removed by the heat treatment. The oxygen may be supplied to the oxide semiconductor film 108 to fill oxygen vacancies in the oxide semiconductor film 108. The temperature of the heat treatment is, for example, 250° C. or higher and 600° C. or lower, preferably 300° C. or higher and 600° C. or lower. In this embodiment, heat treatment is performed at 300° C. for 1 hour.

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

[0161] The planarization insulating film 118 may be any film that can planarize the irregularities of the transistor 150. For example, polyimide resin, acrylic resin, polyimide amide resin, benzocyclobutene It is possible to use organic materials having heat resistance such as polyamide resins, epoxy resins, etc. In addition to the above organic materials, low-k materials and siloxane resins are also available. In addition, it is possible to laminate multiple insulating films made of these materials. In this embodiment, the planarization insulating film 118 may be formed of a A 1.5 μm acrylic resin is used.

[0162] As described above, the transistor 150 described in this embodiment has a channel formation region formed of an oxide A semiconductor film is used, and copper, a low-resistance material, is used for the gate electrode, source electrode, and drain electrode. In addition, the backchannel of the oxide semiconductor film is formed when the source electrode and the drain electrode are formed. Since the panel side does not come into contact with the copper film, there is no risk of adhesion or diffusion to the oxide semiconductor film. In addition, the gate electrode, the source electrode, and the drain electrode can be formed by the copper element. Each of them uses a copper film and has a barrier metal that can suppress the diffusion of copper elements. Therefore, it is a transistor with stable electrical characteristics and little signal delay caused by wiring resistance. The data can be provided.

[0163] The configurations, methods, etc. described in this embodiment may be different from the configurations, methods, etc. described in other embodiments. They can be used in appropriate combination.

[0164] (Embodiment 2) In this embodiment mode, a modification of the semiconductor device shown in Embodiment 1 and a semiconductor device A manufacturing method of the semiconductor device, which is different from the manufacturing method of the semiconductor device described above, will be described with reference to FIGS. Note that the same reference numerals as those shown in Figs. 1 to 5 are used and the explanations thereof will be repeated. is omitted.

[0165] <Configuration Example 2 of Semiconductor Device> FIG. 6 shows a configuration example of a transistor 250 and a signal line region 260. 6B is a plan view of the transistor 250 and the signal line region 260. In order to avoid complication, FIG. The transistor 250 and some of the components of the signal line region 260 (for example, the gate insulating film 2 06, the second metal film 210b, etc.) are omitted in the illustration.

[0166] The semiconductor device shown in FIG. 6 includes a gate electrode 204 formed on a substrate 102 and a gate A gate insulating film 206 is formed on the gate electrode 204. The gate insulating film 206 is in contact with the gate electrode 204. The oxide semiconductor film 108 is formed in a position overlapping with the oxide semiconductor film 104. The source electrode 210 and the drain electrode 212 are electrically connected to each other. The signal line 232 includes a first metal film 210a, a second metal film The second metal film 210b is a first metal film, and the third metal film 210c is a second metal film. The source electrode 21 is formed in an area inside the ends of the first metal film 210a and the second metal film 210c. The drain electrode 212 is made of a first metal film 210a, a first metal film 212a, a third metal film 212b, and a The second metal film 210c and the third metal film 212c.

[0167] The gate electrode 204 is made up of a first gate electrode 204a and a second gate electrode 204b. The first gate electrode 204a is made of tungsten, tantalum, titanium, and molybdenum. It is preferable that the second gate electrode 204b contains copper. For example, In this embodiment, a tungsten film is used as the first gate electrode 204a, and A copper film is used as the gate electrode 204b of the second gate electrode 204. By doing so, it is possible to obtain a gate electrode 204 with low resistance. By providing the second gate electrode 204a, the substrate 102 and the copper film used as the second gate electrode 204b and / or the copper in the copper film used as the second gate electrode 204b. The diffusion of elements can be suppressed.

[0168] The gate insulating film 206 is made up of a first gate insulating film 206a and a second gate insulating film 20 The first gate insulating film 206a is made up of the second gate electrode 204b. It is sufficient that the silicon nitride film has a function of suppressing the diffusion of copper elements in the copper film used as the silicon nitride film. , a silicon nitride oxide film, an aluminum oxide film, an aluminum nitride oxide film, etc. The second gate insulating film 206b is formed on the oxide semiconductor film 108 to be formed later. The film may be a silicon oxide film, a silicon oxynitride film, etc., as long as it has a function of supplying oxygen to the For example, in this embodiment, the first gate insulating film 206a and A silicon nitride film is used as the second gate insulating film 206b, and a silicon oxynitride film is used as the second gate insulating film 206c. By forming the gate insulating film 206 with such a laminated structure, the gate electrode 204 and The copper film is formed by the oxidation of the oxide semiconductor film 108. Oxygen can be supplied.

[0169] In addition, the first metal film 210a, the first metal film 212a, the third metal film 210c, and The third metal film 212c is selected from the group consisting of tungsten, tantalum, titanium, and molybdenum. It is preferable to use a metal film containing one or more elements selected from the above, or a metal nitride film.

[0170] For example, in this embodiment, the first metal film 210a and the first metal film 212a A tungsten film is used as the third metal film 210c and the third metal film 212c. A tantalum nitride film is used.

[0171] In addition, the second metal film 210b preferably contains copper. For this purpose, a copper film is used as the second metal film 210b.

[0172] In this manner, the source electrode 210 and the drain electrode 212 used in the transistor 250 The structure of the signal line 232 is different from that of the source electrode 210 and the drain electrode 212. By electrically connecting the signal line 232 having a structure using a film, the signal delay caused by the wiring resistance is reduced. In addition, the source electrode 210 and the drain electrode 220 used in the transistor 250 can be suppressed. By using no material containing copper for the rain electrode 212, the oxide semiconductor film 10 This is effective in disposing the copper element, which may diffuse into the electrode 8, at a separate location. The signal line 232, the source electrode 210, and the drain electrode 212 are formed in the same semiconductor manufacturing process. Since the semiconductor device can be manufactured in a short time, there is an excellent effect of reducing manufacturing costs.

[0173] Next, referring to FIG. 7 and FIG. 8, the transistor 250 and the signal line region 260 shown in FIG. A method for producing the above will be described.

[0174] <Method 2 for manufacturing semiconductor device> First, a gate electrode 204, a gate insulating film 206, and an oxide semiconductor film 102 are formed on a substrate 102. The gate electrode 204, the gate insulating film 206, and the oxide semiconductor film 108 are formed. Regarding step 08, the steps shown in FIGS. 2A to 2D in Embodiment 1 can be referred to. After that, a gate insulating film 206 and an oxide semiconductor film 108 are formed on the gate insulating film 206 and the oxide semiconductor film 108. , a first metal film 209a which becomes a source electrode, a drain electrode, and a signal line, and a second A metal film 209b is formed (see FIG. 7(A)).

[0175] The first metal film 209a is made of tungsten, tantalum, titanium, or molybdenum. It is preferable that the metal film contains one or more elements selected from the above, or a metal nitride film. In the embodiment, the first metal film 209a is formed by using a sputtering method. A tungsten film having a thickness of 50 nm is used.

[0176] The first metal film 209a may have a laminated structure. For example, the first metal film 209a The first layer is selected from tungsten, tantalum, titanium, and molybdenum. The second layer of the first metal film 209a is a metal film containing one or more elements, and the second layer is tungsten nitride. One or more elements selected from the group consisting of tantalum nitride, titanium nitride, and molybdenum nitride are added to the and a laminated structure of a metal nitride film containing the metal nitride.

[0177] The first metal film 209a is in contact with the oxide semiconductor film 108. A material that does not extract oxygen from the oxide semiconductor film 108 to become n-type, or a material that diffuses into the oxide semiconductor film 108 to become n-type The first metal film 209a is made of a material that does not cause the metal to be broken. It is preferable to use a material that suppresses diffusion of copper elements from the copper film to the oxide semiconductor film 108 .

[0178] The second metal film 209b is preferably a film containing copper. Alternatively, a copper alloy containing a few weight percent of aluminum, gold, silver, zinc, tin, nickel, or the like may be used. In this embodiment, the second metal film 209b is formed by using a sputtering method. A copper film having a thickness of 200 nm is used.

[0179] Next, a resist is applied onto the second metal film 209b, and a first patterning is performed. A mask 241 is formed (see FIG. 7(B)).

[0180] The resist mask 241 is made of the same material as the resist mask 141 shown in the first embodiment. and methods.

[0181] Next, a part of the second metal film 209b is removed by a first etching process, and the second metal film 2 10b is formed (see FIG. 7(C)).

[0182] The second metal film 209b is preferably removed by wet etching. The chemical used in the wet etching method is the same as that used to etch the second metal film 209b. Any chemical solution that can remove the first metal film 209a and does not cause the first metal film 209a to disappear may be used. For example, A tungsten film is used as the first metal film 209a, and a copper film is used as the second metal film 209b. In this case, the chemical solution is a mixture of water, hydrogen peroxide, and carboxylic acid, or water, phosphoric acid, and nitric acid. A mixture of sulfuric acid and potassium sulfate can be used.

[0183] In addition, the wet etching time is adjusted to perform isotropic etching, and the resist mask is removed. Alternatively, the side surface of the second metal film 210b may be recessed inward from the side surface of the groove 241. .

[0184] In this manner, during the first etching, the second metal film 2 09b is left, and the second metal film 209 is left in the region where the oxide semiconductor film 108 is formed. Remove b.

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

[0186] The resist mask 241 can be removed by the same method as that described in the first embodiment. This can be done in the same manner as in the removal method of the first embodiment.

[0187] The third metal film 209c is formed by the same method and material as the first metal film 209a. In this embodiment, the third metal film 209c can be formed as follows. A tantalum nitride film having a thickness of 100 nm formed by sputtering is used.

[0188] Next, a resist is applied onto the third metal film 209c, and a second patterning is performed. A mask 242 is formed (see FIG. 8(A)).

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

[0190] Next, the first metal film 209a and a part of the third metal film 209c are subjected to a second etching. The first metal film 210a, the first metal film 212a, the third metal film 210c, and Then, a third metal film 212c is formed (see FIG. 8(B)).

[0191] The second etching is performed to remove the second metal film 210b removed by the first etching. The first metal film 209a and the third metal film 209c are removed from the outside of the end portion.

[0192] The first metal film 209a and the third metal film 209c are removed by dry etching. The gas used in the dry etching method is, for example, A tungsten film is used as the first metal film 209a, and a tungsten nitride film is used as the third metal film 209c. When using a quartz film, a mixture of SF6 and O2, or a mixture of SF6 and BCl3, etc. It can be used.

[0193] In addition, when the first metal film 209a and the third metal film 209c are etched, oxide The etching conditions are optimized so that the semiconductor film 108 is etched without being divided. However, it is desirable that only the first metal film 209a and the third metal film 209c are It is possible to obtain a condition in which the oxide semiconductor film 108 is not etched at all. It is difficult to etch the first metal film 209a and the third metal film 209c, because the oxide semiconductor The conductive film 108 is partially etched to form an oxide semiconductor film 108 having a groove (a recess). This can sometimes happen.

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

[0195] In this way, the signal line 232 using the copper film as the second metal film 210b and the second metal film The source electrode 210 and the drain electrode 212 without 210b are fabricated in the same process. It is possible.

[0196] The resist mask 242 can be removed by the same method as that for removing the resist mask 241. This can be done by the technique.

[0197] After the signal line 232, the source electrode 210, and the drain electrode 212 are formed, an oxide semiconductor It is preferable to clean the conductive film 108 (more specifically, the back channel side). The conductive film 108 can be cleaned by, for example, oxygen plasma treatment or dilute hydrofluoric acid treatment. By carrying out such cleaning, the source electrode 2 10, and the etching gas components used in forming the drain electrode 212, or the resist matrix. Residues of the mask 242 and the like can be removed from the oxide semiconductor film 108. 08 can be made more highly purified.

[0198] After the signal line 232, the source electrode 210, and the drain electrode 212 are formed, a heat treatment is performed. The temperature of the heat treatment is 250° C. or higher and 650° C. or lower, preferably 450° C. or higher. The upper limit is 600°C or less, or less than the distortion point of the substrate.

[0199] Through the above steps, the transistor 250 and the signal line region 260 described in this embodiment are formed. is formed.

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

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

[0202] In this manner, the configuration of the source electrode 210 and the drain electrode 212 of the transistor 250 The configuration of the signal line 232 in the signal line region 260 is different. A signal line 232 using a copper film is electrically connected to the signal line 212, thereby reducing the signal caused by the wiring resistance. In addition, the source electrode 210 used in the transistor 250 can be In addition, the drain electrode 212 is not formed using a material containing copper, so that the oxide semiconductor This is effective in separating copper elements that may diffuse into the film 108 . In addition, the signal line 232, the source electrode 210, and the drain electrode 212 are formed in the same semiconductor manufacturing process. It can be produced in one process, which has the excellent effect of reducing manufacturing costs. do.

[0203] The configurations, methods, etc. described in this embodiment may be different from the configurations, methods, etc. described in other embodiments. They can be used in appropriate combination.

[0204] (Embodiment 3) A display device using the transistors or signal lines illustrated in the first and second embodiments In addition, a display device having the above-mentioned function can be manufactured by forming a part of a driver circuit including a transistor. Alternatively, the entire display can be formed on the same substrate as the pixel section to form a system-on-panel. An example of the display device will be described with reference to FIG.

[0205] In FIG. 9, a pixel section 302 and a source driver circuit are provided on a first substrate 300. A sealant 312 is provided so as to surround the gate driver circuit section 304 and the gate driver circuit section 306. In addition, a pixel section 302, a source driver circuit section 304, and a gate driver circuit section The second substrate 301 is provided on the path portion 306. The driver circuit section 304 and the gate driver circuit section 306 are attached to the first substrate 300 by a sealant. 312 and the second substrate 301, and is sealed together with the display element.

[0206] In FIG. 9, the area surrounded by the seal material 312 on the first substrate 300 A pixel section 302, a source driver circuit section 304, and a gate driver The circuit section 306 is electrically connected to an FPC terminal section 308 (FPC: Flexible Printed Circuit). The FPC terminal portion 308 is provided with an FP C316 is connected to the pixel section 302, the source driver circuit section 304, and the gate driver Various signals and potentials are provided to the circuit section 306 through an FPC 316 .

[0207] In FIG. 9, a pixel section 302, a source driver circuit section 304, a gate driver circuit section A signal line 310 is connected to the path portion 306 and the FPC terminal portion 308. Various signals and potentials supplied from the signal line 316 are transmitted to the pixel portion 302, The source driver circuit section 304, the gate driver circuit section 306, and the FPC terminal section 308 Given.

[0208] In addition, in FIG. 9, the source driver circuit section 304 and the gate driver circuit section 30 6 is formed on the same first substrate 300 as the pixel section 302. For example, only the gate driver circuit unit 306 is formed on the first substrate 300. Alternatively, only the source driver circuit section 304 may be formed on the first substrate 300. In this case, a separate source driver circuit or a substrate on which a gate driver circuit, etc. are formed is used. A substrate (for example, a driving circuit board formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is placed on a first substrate. It may also be configured to be mounted on a board 300.

[0209] The method of connecting the separately formed drive circuit board is not particularly limited, and may be any method such as COG (Chip On Glass) method, wire bonding method, or TAB (Tap The Automated Bonding (E-BA) method can be used.

[0210] The display device includes a panel in which a display element is sealed, and a controller for the panel. This includes modules in which ICs, etc., including lasers, are mounted.

[0211] In this specification, the term "display device" refers to an image display device, a display device, or Refers to light sources (including lighting devices). Also refers to connectors, such as FPC or TAB tape. or a module with a TCP (Tape Carrier Package) attached Modules with printed wiring boards on the ends of TAB tape or TCP, or display elements Also displays all modules with drive circuit boards or ICs directly mounted using the COG method. This is included in the device.

[0212] A pixel section 302, a source driver circuit section 304, The gate driver circuit section 306 has a plurality of transistors, and The transistors described in the above embodiment and the transistors described in the second embodiment can be used. The case where the transistor described in Embodiment 2 is used will be described.

[0213] In addition, examples of the display element provided in the display device include a liquid crystal element (also called a liquid crystal display element), A light emitting element (also called a light emitting display element) can be used. A light emitting element can be a light emitting element that emits a current or a voltage. This category includes elements whose brightness is controlled by the Fluorescent (EL) displays, organic electroluminescence (OLED), etc. Electronic inks, etc. A display medium in which the contrast changes due to electrical effects can also be used.

[0214] One mode of a display element provided in a display device will be described with reference to FIGS. 10 and 11. The display device shown in FIG. 10 and FIG. 11 corresponds to a cross-sectional view taken along the dashed line QR in FIG. do.

[0215] The display device shown in FIG. 10 has a first substrate 300 and an FPC terminal section 308 provided thereon. A terminal electrode made up of a first metal film 360a, a second metal film 360b, and a third metal film 360c. The terminal electrode 360 ​​is connected to a terminal of the FPC 316 and an anisotropic conductive film 38. 0.

[0216] The terminal electrode 360 ​​is connected to the source electrodes of the transistors 350 and 352, It is formed in the same process as the drain electrode and the signal line 310 .

[0217] A pixel section 302 and a source driver circuit section 304 are provided on the first substrate 300. 10 and 11, the pixel portion 302 includes a A transistor 350 and a transistor 352 included in the source driver circuit section 304 Illustrated here.

[0218] In this embodiment, the transistor 350 included in the pixel portion 302 and the source The transistors 352 included in the driver circuit section 304 are configured to be the same size. However, the present invention is not limited to this. The size (L / W) or the number of transistors used is changed as appropriate. 10 and 11, the gate driver circuit section 306 is Although not shown, the connection destination or the connection method is different, but the source driver circuit unit 304 The same configuration can be used.

[0219] Also, in FIG. 10 and FIG. 11, a transistor 350 and a transistor 352, The signal line 310 is the same as the transistor 250 and the signal line 23 shown in the second embodiment. 2.

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

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

[0222] In this manner, the transistor 350 and the transistor 352 do not use a copper film. The source electrode and the drain electrode are configured in a single structure, and the signal line 310 and the terminal electrode The transistor 350 and the transistor 360 are made of a copper film. 352, the signal line 310, and the terminal electrode 360 ​​are used, It is possible to provide a display device having low resistance electrodes or wirings with the desired characteristics.

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

[0224] In this embodiment, a silicon oxynitride film is used as the insulating film 364, and the protective insulating film 3 An aluminum oxide film is used as the insulating film 364 and the protective insulating film 36. The film 6 can be formed by sputtering or plasma CVD.

[0225] The silicon oxynitride film provided as the insulating film 364 is provided in contact with the oxide semiconductor film. Thus, oxygen can be supplied to the oxide semiconductor film.

[0226] The aluminum oxide film provided as the protective insulating film 366 is a film that can absorb impurities such as hydrogen and water, and The membrane has a high blocking effect that does not allow both oxygen and oxygen to pass through. The aluminum film is free of impurities such as hydrogen and water that can cause fluctuations during and after the manufacturing process. The contamination of the oxide semiconductor film with foreign substances and the oxidation of oxygen, which is the main component of the oxide semiconductor film, It functions as a protective film to prevent emission from the compound semiconductor film.

[0227] The planarization insulating film 368 may be made of a polyimide resin, an acrylic resin, or a polyimide. Heat resistance of amide resin, benzocyclobutene resin, polyamide resin, epoxy resin, etc. In addition, the insulating film formed of these materials can be used in combination. The planarization insulating film 368 may be formed by stacking several layers.

[0228] In addition, in the display device shown in this embodiment, the transistor formed in the source driver circuit portion 304 A planarization insulating film 368 is provided on the transistor 352, and an oxide film is formed on the planarization insulating film 368. The conductive film 370a is provided at a position overlapping the channel formation region of the semiconductor film. However, the present invention is not limited to this configuration, and the conductive film 370a may not be provided. By providing the conductive film 370a at a position overlapping with the channel formation region of the oxide semiconductor film, In this way, the change in the threshold voltage of the transistor 352 before and after the BT test can be reduced. The conductive film 370a may have the same potential as the gate electrode of the transistor 352. Alternatively, the gate electrode may be different from the gate electrode, and may function as a second gate electrode. The potential of the film 370a may be GND, 0V, or may be in a floating state.

[0229] The conductive film 370a shields the external electric field, that is, the external electric field is prevented from reaching the inside (transistor). The function of preventing the circuit part including resistor 352 from being affected (especially the electrostatic shield against static electricity) The shielding function of the conductive film 370a prevents the device from being affected by external electric fields such as static electricity. This can prevent the electrical characteristics of the transistor 352 from fluctuating. The conductive film 370a may be provided over a wide area so as to overlap the transistor 352. This is expected to further improve electrostatic shielding performance.

[0230] In addition, in the display device described in this embodiment, the transistor 350 formed in the pixel portion 302 A planarization insulating film 368 is provided on the upper surface of the insulating film 368. A source electrode or a drain electrode is formed on the planarization insulating film 368. The conductive film 370b is connected to the pixel electrode. The portion 302 functions as a pixel electrode.

[0231] The transistor 350 provided in the pixel portion 302 is electrically connected to a display element. The display element is not particularly limited as long as it can display an image. can be used.

[0232] The display device shown in FIG. 10 is an example of a liquid crystal display device using liquid crystal elements as display elements. In FIG. 10, a liquid crystal element 402, which is a display element, includes a conductive film 370b, a counter electrode 404, and a liquid crystal layer 406. The liquid crystal layer 406 is sandwiched between insulating layers functioning as alignment layers. An insulating film 410 and an insulating film 412 are provided. The counter electrode 404 is disposed on the second substrate 301 side. The conductive film 370b and the counter electrode 404 are laminated with a liquid crystal layer 406 interposed therebetween. It has become.

[0233] The spacers 435 are columnar spacers obtained by selectively etching an insulating film. It is a sensor that is provided to control the thickness (cell gap) of the liquid crystal layer 406. A spherical spacer may be used.

[0234] When liquid crystal elements are used as display elements, thermotropic liquid crystal, low molecular weight liquid crystal, high molecular weight liquid crystal, etc. Liquid crystal, polymer dispersed liquid crystal, ferroelectric liquid crystal, antiferroelectric liquid crystal, etc. can be used. These liquid crystal materials can exhibit cholesteric, smectic, cubic, and chromatic phases depending on the conditions. It shows an isotropic phase, an isotropic phase, etc.

[0235] In addition, when the in-plane switching method is adopted, liquid crystal that exhibits a blue phase without using an alignment film may be used. The blue phase is one of the liquid crystal phases. When the temperature of a cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the black phase to the isotropic phase. In order to improve the temperature range, a liquid crystal composition containing a chiral agent of several weight percent or more is used. The liquid crystal composition containing the liquid crystal exhibiting the blue phase and the chiral agent is used in the liquid crystal layer. Since the orientation angle is short and the liquid crystal display is optically isotropic, no alignment treatment is required, and the viewing angle dependency is small. Since there is no need to provide an alignment film, rubbing is also unnecessary. This can prevent electrostatic damage caused by electrostatic discharge, and can prevent defects and damage to liquid crystal display devices during the manufacturing process. This makes it possible to improve the productivity of the liquid crystal display device. The electrical characteristics of transistors using a nitride semiconductor film are affected by static electricity. Therefore, the transistor using the oxide semiconductor film may be significantly changed and deviate from the design range. It is more effective to use a blue phase liquid crystal material in a liquid crystal display device having a transistor.

[0236] The specific resistance of the liquid crystal material is 1×10 9 Ω cm or more, preferably 1×10 1 1 Ω cm or more, and more preferably 1×10 12 Ω·cm or more. The specific resistance values ​​specified in the specification are those measured at 20°C.

[0237] The size of the storage capacitor provided in the liquid crystal display device is determined by the capacitance of the transistor arranged in the pixel portion. The capacitance is set so that the charge can be held for a predetermined period of time, taking into account the current flow and other factors. The size may be set in consideration of the off-state current of the transistor. By using a transistor including an oxide semiconductor film in which the formation of a gate insulating film is suppressed, A storage capacitor having a capacity of 1 / 3 or less, preferably 1 / 5 or less, of the capacity of the liquid crystal. It is sufficient to set

[0238] The oxide semiconductor film used in this embodiment is highly purified and in which formation of oxygen vacancies is suppressed. The transistor can reduce the current value in the off state (off-state current value). This allows the retention time of electrical signals such as image signals to be extended, and writing is possible while the power is on. The interval can also be set longer, so the frequency of refresh operations can be reduced. This has the effect of reducing power consumption.

[0239] In addition, the oxide semiconductor film used in this embodiment is highly purified and in which formation of oxygen vacancies is suppressed. A transistor having such a structure can achieve a relatively high field effect mobility and can therefore be driven at high speed. For example, by using such a transistor capable of high speed operation in a liquid crystal display device, The switching transistor in the pixel section and the driver transistor used in the drive circuit section are the same. In other words, it is possible to form the driver circuit on a single substrate, such as a silicon wafer. Since it is not necessary to use a semiconductor device formed by a method for manufacturing a semiconductor device, the number of components of the semiconductor device can be reduced. In addition, by using a transistor capable of high speed operation in the pixel portion, It is possible to provide high quality images.

[0240] In addition, the switching transistors in the pixel section and the driver transistors used in the driver circuit section The signal lines connected to the resistors are made of copper-containing wires. There is little signal delay or the like caused by this, making it possible to use it in display devices with large screens.

[0241] There are two types of LCD displays: TN (Twisted Nematic) mode, IPS (In- Plane-Switching mode, FFS (Fringe Field Switching) mode tching) mode, ASM(Axially Symmetric aligned) Micro-cell) mode, OCB(Optical Compensated) Birefringence mode, FLC (Ferroelectric Liquid id Crystal) mode, AFLC (AntiFerroelectric Li quid Crystal mode etc. can be used.

[0242] In addition, normally black type liquid crystal display devices, for example, those using a vertical alignment (VA) mode The liquid crystal display device may be a transmission type liquid crystal display device. There are several types of vertical alignment modes, including: For example, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode The present invention can also be applied to VA type liquid crystal display devices. A type of liquid crystal display device is a type of device that controls the arrangement of liquid crystal molecules in a liquid crystal display panel. In VA type LCD devices, the liquid crystal molecules are aligned relative to the panel surface when no voltage is applied. It is a method of dividing a pixel into several regions (subpixels). The molecule is divided into two parts, each of which is designed to tilt in a different direction. A method called multidomain design can be used.

[0243] In addition, in display devices, black matrices (light-shielding layers), polarizing members, phase difference members, reflectors, Optical members (optical substrates) such as anti-reflection members are provided as appropriate. For example, a polarizing substrate and a retardation Circular polarization by the substrate may be used. Also, backlight, sidelight, etc. may be used as the light source. It may be used.

[0244] In addition, the display method in the pixel section uses the progressive method, interlace method, etc. In addition, the color elements controlled by pixels when displaying colors are RGB (RGB=RGB). The color is not limited to the three colors RGBW (W stands for white). ), or RGB plus one or more colors such as yellow, cyan, or magenta. The size of the display area may be different for each dot of the color element. The present invention is not limited to color display devices, but may be applied to monochrome display devices. It is also possible.

[0245] In addition, a light-emitting device using electroluminescence is used as a display element included in the display device. The light-emitting element that utilizes electroluminescence can be applied to a light-emitting material They are classified according to whether the material is an organic compound or an inorganic compound. The latter is called an inorganic EL element.

[0246] In an organic EL element, electrons and positive electrodes are released from a pair of electrodes by applying a voltage to the light-emitting element. The holes are then injected into a layer containing a light-emitting organic compound, and a current is passed through them. The recombination of carriers (electrons and holes) causes light-emitting organic compounds to form excited states. When the excited state returns to the ground state, light is emitted. Such a light-emitting element is called a current-excitation type light-emitting element.

[0247] Inorganic EL elements are classified into dispersion type inorganic EL elements and thin film type inorganic EL elements depending on the element structure. Dispersion-type inorganic EL elements have a light-emitting layer in which particles of light-emitting material are dispersed in a binder. The emission mechanism is a donor-based ion exchange reaction that utilizes the donor and acceptor levels. This is an acceptor recombination type emission. Thin-film inorganic EL elements sandwich the light-emitting layer between dielectric layers. The structure is sandwiched between electrodes, and the light emission mechanism is the inner shell electron transition of metal ions. This is a localized light emission that utilizes organic EL elements. do.

[0248] In order to extract light emitted from the light emitting element, at least one of a pair of electrodes needs to be light-transmitting. Then, a transistor and a light emitting element are formed on the substrate, and light is emitted from the surface opposite the substrate. Top emission, bottom emission, and both the substrate side and the opposite side of the substrate. There are light emitting devices with a double-sided emission structure that emits light from both sides, and light emitting devices with any emission structure can be used. It is possible.

[0249] FIG. 11 shows an example of a display device using light-emitting elements as display elements. The transistor 450 is electrically connected to the transistor 350 provided in the pixel portion 302. The light emitting element 450 is configured by stacking a conductive film 370b, an electroluminescent layer 452, and an upper electrode 454. The structure is not limited to the configuration shown in FIG. Additionally, the configuration of the light emitting element 450 can be changed as appropriate.

[0250] The partition 456 is formed using an organic insulating material or an inorganic insulating material. For example, the partition wall is preferably made of a photosensitive resin material. When forming the conductive film 456, a photosensitive resin material is applied onto the planarization insulating film 368 and the conductive film 370b. Then, a desired area is irradiated with light to form an opening in a portion of the conductive film 370b. The side wall of the opening can be formed to be an inclined surface having a continuous curvature.

[0251] The electroluminescent layer 452 may be composed of a single layer or may be composed of a plurality of layers stacked together. It doesn't matter whether it is done or not.

[0252] In order to prevent oxygen, hydrogen, water, carbon dioxide, etc. from entering the light emitting element 450, the upper electrode 454 A protective film may be formed on the partition wall 456. The protective film may be a silicon nitride film, a nitride A silicon oxide film or the like can be formed. The space sealed by the seal material 312 is sealed with a filler 458. In order to prevent exposure to the outside air, a protective film (pasting film) with high airtightness and low outgassing is used. Packaging (enclosure) with a cover material (such as a laminated film or ultraviolet curing resin film) It is preferable that

[0253] Filling material 458 can be inert gas such as nitrogen or argon, or ultraviolet curing resin. Alternatively, thermosetting resins can be used, such as PVC (polyvinyl chloride) and acrylic resins. , polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral ) or EVA (ethylene vinyl acetate) can be used. For example, filler 45 Nitrogen can be used as 8.

[0254] If necessary, a polarizing plate or a circular polarizing plate (including an elliptical polarizing plate) may be attached to the light-emitting surface of the light-emitting element. ), retardation plates (lambda / 4 plates, lambda / 2 plates), color filters, and other optical films are appropriately installed. In addition, the polarizing plate or the circular polarizing plate may be provided with an anti-reflection film. Anti-glare treatment can be applied to further diffuse reflected light and reduce glare.

[0255] In addition, in FIG. 10 and FIG. 11, the first substrate 300 and the second substrate 301 are In addition to the glass substrate, a flexible substrate can also be used. For example, a transparent plastic substrate can be used. As for plastic, FRP (Fibre Plastics) can be used. Ass-Reinforced Plastics) plate, PVF (Polyvinyl Fluoride) A film, a polyester film or an acrylic resin film can be used. In addition, aluminum foil is sandwiched between PVF film or polyester film. Ports can also be used.

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

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

[0258] (Embodiment 4) The semiconductor device disclosed in this specification can be applied to various electronic devices (including game machines). The electronic device can be, for example, a television device (television or television (also called digital receivers), computer monitors, electronic paper, digital cameras, Digital video cameras and other cameras, digital photo frames, mobile phones (mobile phones, (also called telephone device), portable game machine, personal digital assistant (PDA), mobile terminal (smartphone (including mobile phones, tablet PCs, etc.), audio playback devices, large game machines such as pachinko machines, etc. Examples of electronic devices including the semiconductor device described in the above embodiments are shown in FIGS. This will be explained with reference to FIG.

[0259] FIG. 12A shows a notebook personal computer, which includes a main body 3001 and a housing 30 The embodiment is composed of a display unit 3002, a display unit 3003, a keyboard 3004, etc. By applying the semiconductor device shown in any one of the above embodiments to the display portion 3003, a stable electric A notebook type personal computer with low signal delay caused by wiring resistance. It can be used as a data.

[0260] FIG. 12B shows a portable digital assistant (PDA), and a main body 3021 includes a display unit 3023 and An external interface 3025 and an operation button 3024 are also provided. The semiconductor device shown in any of the above embodiments has a stylus 3022 as an accessory for the semiconductor device. By applying the device to the display unit 3023, it is possible to obtain more stable electrical characteristics and reduce wiring resistance. It is possible to provide a personal digital assistant (PDA) with less signal delay due to resistance.

[0261] FIG. 12C shows an example of an electronic book. For example, an electronic book 2700 has a housing 2 The device is made up of two housings, housing 2701 and housing 2703. 03 is integrated with an axis portion 2711, and performs opening and closing operations around the axis portion 2711. This configuration makes it possible to operate like a paper book. .

[0262] A display unit 2705 is incorporated in the housing 2701, and a display unit 2707 is incorporated in the housing 2703. The display unit 2705 and the display unit 2707 are configured to display a continuous screen. Alternatively, a different screen may be displayed. For example, a text is displayed on the right display unit (display unit 2705 in FIG. 12C) and In the above embodiment, an image can be displayed on the display unit (display unit 2707 in FIG. 12C). The semiconductor device shown in any one of the above embodiments is applied to the display portion 2705 and the display portion 2707. This allows for stable electrical characteristics and reduces signal delays caused by wiring resistance. A semi-transmissive or reflective liquid crystal display device is used as the display unit 2705. In the case of a solar panel, it is expected that it will be used in relatively bright conditions, so a solar panel will be installed and the solar panel will be used to The battery may be configured to generate electricity by using the power source and charge the battery. The use of lithium ion batteries has the advantage of enabling miniaturization.

[0263] FIG. 12C shows an example in which an operating unit and the like are provided in the housing 2701. For example, In the housing 2701, a power supply 2721, operation keys 2723, a speaker 2725, etc. are arranged. The operation keys 2723 can be used to turn pages. A keyboard, a pointing device, etc. may be provided on one side. On the back and sides of the device, there are external connection terminals (earphone terminal, USB terminal, etc.), a recording medium insertion port, etc. Furthermore, the electronic book 2700 may have a function as an electronic dictionary. It may be configured such that

[0264] The electronic book 2700 may be configured to transmit and receive information wirelessly. The desired book data can be purchased and downloaded from the electronic book server. It is also possible.

[0265] FIG. 12D shows a mobile phone, which is composed of two housings, a housing 2800 and a housing 2801. The housing 2801 includes a display panel 2802, a speaker 2803, a microphone, and the like. 2804, a pointing device 2806, a camera lens 2807, an external connection terminal The housing 2800 also includes a solar cell for charging the mobile phone. The device is equipped with a cell 2810, an external memory slot 2811, and the like. The semiconductor device described in any one of the above embodiments is incorporated in the display panel 801. By applying this to the 2802, it has stable electrical characteristics and reduces the signal loss caused by wiring resistance. It is possible to provide a mobile phone with little signal delay.

[0266] The display panel 2802 is equipped with a touch panel, and in FIG. The multiple operation keys 2805 are indicated by dotted lines. It also includes a boost circuit to boost the input voltage to the voltage required by each circuit.

[0267] The display direction of the display panel 2802 changes appropriately depending on the usage mode. The camera lens 2807 is located on the same surface as the camera 2802, so video calls are possible. The speaker 2803 and the microphone 2804 are not limited to voice calls, but can also be used for video calls. , recording, playback, etc. are possible. Furthermore, the housing 2800 and the housing 2801 can be slid apart, As shown in Figure 12(D), the device can be folded from the unfolded state to the folded state, making it easy to carry. Suitable miniaturization is possible.

[0268] The external connection terminal 2808 can be connected to various cables such as AC adapters and USB cables. It is possible to charge the battery and to communicate data with a personal computer, etc. By inserting a recording medium into the external memory slot 2811, it is possible to store and transfer a larger amount of data. Cut.

[0269] In addition to the above functions, it also has infrared communication function, TV reception function, etc. Good too.

[0270] FIG. 12(E) shows a digital video camera, which includes a main body 3051 and a display unit (A) 3057. , eyepiece 3053, operation switch 3054, display unit (B) 3055, battery 3056 The semiconductor device described in any one of the above embodiments is configured as a display portion ( By applying it to the display part (B) 3055, it has stable electrical characteristics. Furthermore, a digital video camera with little signal delay caused by wiring resistance can be obtained.

[0271] FIG. 12(F) shows an example of a television device. The television device 9600 is A display portion 9603 is incorporated in the housing 9601. In addition, in this example, the housing 9601 is supported by a stand 9605. The semiconductor device described in any of the above embodiments is configured as a display portion 9603. By applying this to the MOSFET, it has stable electrical characteristics and reduces signal delays caused by wiring resistance. The television device may be a television device without a built-in microphone.

[0272] The television device 9600 can be operated using an operation switch provided on the housing 9601 or a separate remote control. This can be done by a remote control device. A display unit for displaying information output from the input unit may be provided.

[0273] The television device 9600 includes a receiver, a modem, and the like. This allows reception of general television broadcasts, and can also be used for wired or wireless reception via a modem. By connecting to a network, communication can be one-way (sender to receiver) or two-way It is also possible to communicate information in both directions (between sender and receiver, or between receivers). .

[0274] FIG. 13 shows an example of a tablet terminal. FIG. 13(A) to FIG. 13(C) show: FIG. 13(A) shows a tablet terminal 5000, and FIG. 13(B) shows a tablet terminal 6000. There are.

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

[0276] The tablet terminal 5000 includes a housing 5001, a display unit 5003, a power button 5005, A front camera 5007, a rear camera 5009, a first external connection terminal 5011, and a second external It is composed of a portion connection terminal 5013 and the like.

[0277] The display unit 5003 is incorporated in the housing 5001 and can also be used as a touch panel. For example, an icon 5015 or the like can be displayed on the display unit 5003 to In addition, the housing 5001 is equipped with a A front camera 5007 is built into the face side, allowing the user to take pictures. In addition, a rear camera 5009 is built into the rear side of the housing 5001, The camera can capture an image on the opposite side. The camera also has a first external connection terminal 5 011 and a second external connection terminal 5013. For example, the first external connection terminal 5 011 outputs audio to earphones or the like, and the second external connection terminal 5013 outputs data. It is possible to move around etc.

[0278] Next, a tablet terminal 6000 shown in FIG. 13(D) includes a first housing 6001 and a second housing 6002. A housing 6003, a hinge portion 6005, a first display portion 6007, a second display portion 6009, and a power supply It is composed of a button 6011, a first camera 6013, a second camera 6015, etc. .

[0279] The first display unit 6007 is incorporated in the first housing 6001, and the second display The first display unit 6007 and the second display unit 6009 are incorporated in the second housing 6003. The second display unit 6009 uses, for example, the first display unit 6007 as a display panel, The second display unit 6009 is a touch panel. The icon 6017 is checked, and the icon 6019 is displayed on the second display unit 6009. displays a keyboard 6021 (actually, a keyboard image displayed on the second display unit 6009). The first display unit can be used to select an image or input text. The display unit 6007 is a touch panel, and the second display unit 6009 is a display panel. Both the first display unit 6007 and the second display unit 6009 are configured as touch panels. This is also fine.

[0280] The first housing 6001 and the second housing 6003 are connected by a hinge portion 6005. The first housing 6001 and the second housing 6003 can be opened and closed. By adopting such a configuration, when carrying the tablet terminal 6000, the first housing A first display unit 6007 incorporated in a housing 6001 and a second display unit 6003 incorporated in a housing 6004 are shown. By combining the first display unit 6007 and the second display unit 6009, This is preferable because it can protect the surface of the substrate (eg, a plastic substrate, etc.).

[0281] In addition, the first housing 6001 and the second housing 6003 can be separated by a hinge portion 6005. It is also possible to use a structure that allows the use of a convertible type. For example, the first housing 6001 is used in a vertical position and the second housing 6003 is used in a horizontal position. As described above, this is preferable since it broadens the range of use.

[0282] In addition, a first camera 6013 and a second camera 6015 are used to capture 3D images. It is also possible.

[0283] In addition, the tablet terminal 5000 and the tablet terminal 6000 transmit information wirelessly. For example, the desired information may be received by connecting to the Internet or the like wirelessly. It is also possible to configure the information to be purchased and downloaded.

[0284] In addition, the tablet terminal 5000 and the tablet terminal 6000 can store various information (status, Functions for displaying still images, videos, text images, etc.; displaying calendars, dates, times, etc. A function to display information on the display unit, and a touch input function to operate or edit the information displayed on the display unit by touch input. It can have the function of controlling processing by various software (programs), etc. In addition, the display can be equipped with a light sensor that can optimize the brightness of the display according to the amount of external light, A detection device such as a sensor for detecting tilt, such as an accelerometer or the like, may be built in.

[0285] The semiconductor device described in the above embodiment is used in a display portion 5003 of a tablet terminal 5000. First display unit 6007 and / or second display unit 6009 of tablet terminal 6000 By applying this to the MOSFET, it has stable electrical characteristics and reduces signal delays caused by wiring resistance. The device may be a tablet type device that does not have a touch panel.

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

[0287] 102 Substrate 104 Gate electrode 104a first gate electrode 104b Second gate electrode 106 Gate insulating film 106a first gate insulating film 106b Second gate insulating film 108 Oxide semiconductor film 109a First metal film 109b Second metal film 109c Third metal film 110 Source electrode 110a first metal film 110b Second metal film 110c Third metal film 112 Drain electrode 112a First metal film 112b Second metal film 112c Third metal film 114a first insulating film 114b Second insulating film 115 Aluminum Film 116 Aluminum oxide film 118 Planarizing insulating film 141 Resist mask 142 Resist Mask 145 Oxygen 147 Oxygen 150 Transistors 204 Gate electrode 204a First gate electrode 204b Second gate electrode 206 Gate insulating film 206a First gate insulating film 206b Second gate insulating film 209a First metal film 209b Second metal film 209c Third metal film 210 Source electrode 210a First metal film 210b Second metal film 210c Third metal film 212 Drain electrode 212a First metal film 212c Third metal film 232 Signal Line 241 Resist Mask 242 Resist Mask 250 Transistors 260 Signal Line Area 300 Substrates 301 Substrate 302 Pixel section 304 Source driver circuit section 306 Gate driver circuit section 308 FPC terminal section 310 Signal Line 312 Sealing material 316 FPC 350 Transistors 352 Transistor 360 terminal electrode 360a First metal film 360b Second metal film 360c Third Metal Film 364 Insulating Film 366 Protective insulating film 368 Planarizing Insulating Film 370a Conductive film 370b Conductive film 380 Anisotropic Conductive Film 402 Liquid crystal element 404 Counter Electrode 406 Liquid crystal layer 410 Insulating film 412 Insulating film 435 Spacer 450 Light emitting element 452 Electroluminescent layer 454 Upper electrode 456 Bulkhead 458 Filling material 2700 e-books 2701 Case 2703 Case 2705 ​​Display section 2707 Display section 2711 Shaft 2721 Power supply 2723 Operation key 2725 Speaker 2800 Chassis 2801 Case 2802 Display Panel 2803 Speaker 2804 Microphone 2805 Operation key 2806 Pointing Device 2807 Camera lenses 2808 External connection terminal 2810 Solar Cell 2811 External memory slot 3001 Main unit 3002 Case 3003 Display section 3004 Keyboard 3021 Main unit 3022 Stylus 3023 Display section 3024 Operation button 3025 External Interface 3051 Main unit 3053 Eyepiece 3054 Operation switch 3056 Battery 5000 tablet devices 5001 Case 5003 Display section 5005 Power button 5007 Front Camera 5009 Rear Camera 5011 External connection terminal 5013 External connection terminal 5015 Icon 6000 Tablets 6001 Case 6003 Case 6005 Hinge part 6007 Display section 6009 Display section 6011 Power button 6013 Camera 6015 Camera 6017 Text Icon 6019 Icon 6021 Keyboard 9600 Television Equipment 9601 Case 9603 Display section 9605 Stand

Claims

1. A liquid crystal display device having a transistor in a pixel portion, a first conductive layer having a function as a gate electrode of the transistor; a first insulating layer having a region disposed above the first conductive layer; an oxide semiconductor layer having a region located above the first insulating layer and having a channel formation region of the transistor; a second conductive layer having a region located above the oxide semiconductor layer and functioning as a source electrode; a third conductive layer having a region located above the oxide semiconductor layer and functioning as a drain electrode; each of the second conductive layer and the third conductive layer includes a first metal film, a second metal film having a region in contact with an upper surface of the first metal film, and a third metal film having a region in contact with an upper surface and a side surface of the second metal film; the first metal film includes any one of tungsten, tantalum, titanium, and molybdenum; the second metal film includes copper; the first metal film has a region in contact with an upper surface and a side surface of the oxide semiconductor layer, the third metal film does not have a region in contact with the oxide semiconductor layer, the third metal film has a region in contact with an upper surface of the first metal film; LCD display device.

2. A liquid crystal display device having a transistor in a pixel portion, a first conductive layer having a function as a gate electrode of the transistor; a first insulating layer having a region disposed above the first conductive layer; an oxide semiconductor layer having a region located above the first insulating layer and having a channel formation region of the transistor; a second conductive layer having a region located above the oxide semiconductor layer and functioning as a source electrode; a third conductive layer having a region located above the oxide semiconductor layer and functioning as a drain electrode; the first insulating layer includes a first film including nitrogen and silicon, and a second film including oxygen and silicon, the second film having a region disposed above the first film; each of the second conductive layer and the third conductive layer includes a first metal film, a second metal film having a region in contact with an upper surface of the first metal film, and a third metal film having a region in contact with an upper surface and a side surface of the second metal film; the first metal film includes any one of tungsten, tantalum, titanium, and molybdenum; the second metal film includes copper; the first metal film has a region in contact with an upper surface and a side surface of the oxide semiconductor layer, the third metal film does not have a region in contact with the oxide semiconductor layer, the third metal film has a region in contact with an upper surface of the first metal film; LCD display device.

3. In claim 1 or 2, The oxide semiconductor layer includes a first oxide semiconductor layer and a second oxide semiconductor layer having a region disposed above the first oxide semiconductor layer. LCD display device.

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

Images