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. and electronic equipment. [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, oxide semiconductors have been attracting attention.

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

[0004] In addition, in display devices using transistors (for example, liquid crystal panels, organic EL panels), As screen sizes become larger, the use of transistors and other In the case of a display device using an active element, the voltage applied to the element is This can lead to a decrease in display quality, such as uneven display and poor gradation. There was a problem.

[0005] Furthermore, the display device screen resolution is high definition (HD, 1366 x 768), There is a trend towards high definition (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 minimize signal delay for wiring or signal lines. It is being done.

[0007] 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, copper films have poor adhesion to the underlayer, and the copper element in the copper film is a semiconductor material of transistors. It has the drawback that it easily diffuses into the underlying film, deteriorating the transistor characteristics. and to prevent the diffusion of copper elements, a silicon nitride film and 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] Japanese Patent Application Laid-Open No. 2007-123861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-230965 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 the channel formation region is To apply it to a laser, there are problems such as the manufacturing method not being optimal or the structure not being optimal. 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 with stable electrical characteristics and 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 purposes is to provide the following. [Means for solving the problem]

[0011] A bottom-gate transistor using an oxide semiconductor film in 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 first to third metal films. The metal film 2 is made of a material containing copper elements.

[0012] As a method for forming a source electrode and a drain electrode in contact with an oxide semiconductor film, and a second metal film is formed, and a first photolithography process is performed 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 the third metal film is removed by a second etching. The second etching is performed on the outer side of the edge 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 with 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 prevent the occurrence of such a problem. More details are 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. and forming an oxide semiconductor film in contact with the gate insulating film and at a position 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 first etching; forming a third metal film on the first metal film; and performing a second photolithography process on the third metal film. and then removing a portion of the first metal film and the third metal film by 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. a step of forming a second insulating film on the first insulating film; a step of introducing oxygen into 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 each of the above manufacturing methods, the first metal film and the third metal film are made of tungsten, a metal film containing one or more elements selected from tantalum, titanium, and molybdenum; The first metal film may be a metal nitride film, and the second metal film may contain copper.

[0016] In each of the above manufacturing methods, the first etching is performed by wet etching. The second etching may be performed by dry etching.

[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 oxide 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 is 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; The source electrode and the drain electrode are 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 end portions 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, an oxygen-excess first insulating layer 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 film and the planarization insulating film formed on the aluminum oxide film are included. That's fine.

[0020] In each of the above structures, 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; 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, or the like. Preferably, the alloy contains one or more elements selected from the group consisting of nickel, ...

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

[0023] In a semiconductor device using an oxide semiconductor film, stable electrical characteristics and wiring resistance are achieved. It is also possible to provide a method for manufacturing a transistor in which signal delay due to the A semiconductor device including the transistor can be provided. It is possible to provide a high-performance display device having such a structure. [Brief explanation 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. [Figure 2] 1A to 1C are cross-sectional views illustrating an example of a manufacturing process of a semiconductor device. [Figure 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. [Figure 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 illustrating one embodiment of a display device. [Figure 11] FIG. 1 is a cross-sectional view illustrating one embodiment of a display device. [Figure 12] 1A to 1C illustrate examples of electronic devices including semiconductor devices. [Figure 13] 1A and 1B are diagrams illustrating an example of a tablet terminal including a semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the 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 readily understood by those skilled in the art that various modifications can be made to the form and details of the present invention. Therefore, the present invention should not be construed as being limited to the following description of the embodiments. .

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

[0027] In this specification, ordinal numbers such as "first," "second," and "third" refer to the order 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" are used to indicate whether the positional relationship of a component is "directly above" or "below." For example, the term "gate electrode on the gate insulating film" does not necessarily mean "directly under" the gate insulating film. If the expression "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 a limitation. For example, an "electrode" may be used as part of a "wiring." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably with "electrodes" and "wiring." This also includes cases where the wiring is formed integrally.

[0030] Also, the functions of "source" and "drain" can be changed by using transistors with different polarities. Or, when the direction of the current changes during circuit operation, the positions may be swapped. 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 "of" is not subject to any particular restrictions as long as it allows the transmission and reception of electrical signals between connected objects. For example, "things that have some kind of electrical action" include electrodes, wiring, and transistors. It has various functions such as switching elements, resistors, inductors, capacitors, etc. This includes elements such as:

[0032] In this specification, patterning refers to the use of a photolithography process. However, the patterning is not limited to the photolithography process, and may be performed by any method. A process other than the above process can also be used. is to be removed after the etching process.

[0033] (Embodiment 1) In this embodiment mode, one mode of a semiconductor device and a manufacturing method of the semiconductor device 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> 1A and 1B show an example of the structure of a transistor 150. FIG. 1A is a plan view of the transistor 150. 1(B) is a cross-sectional view taken along the line X1-Y1 of FIG. 1(A), and FIG. 1(C) is a cross-sectional view taken along the line X1-Y1 of FIG. 1(A) is a cross-sectional view taken along the line V1-W1 in FIG. 1(A). In order to avoid this, some of the components of the transistor 150 (for example, the gate insulating film 106, etc.) is omitted in the illustration.

[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, and 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 same.

[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. The second gate electrode 104b preferably contains copper. For example, In this embodiment, a tungsten film is used as the first gate electrode 104a, and a 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 low-resistance gate electrode 104. By providing the gate electrode 104a, the substrate 102 and the copper film used as the second gate electrode 104b and / or to improve the adhesion of 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 106b. 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, or the like is used. The second gate insulating film 106b can be formed on the oxide semiconductor film 108, which will be formed later. It is sufficient if the film has a function of supplying oxygen to the substrate. 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 108 is formed later. 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 formed by 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 end portions thereof. .

[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 made of tungsten, tantalum, titanium, or molybdenum. It is preferable to use a metal film containing one or more elements selected from the above, or a metal nitride film. The second metal film 110b and the second metal film 112b preferably contain copper. .

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

[0041] That is, the copper films used as the second metal films 110b and 112b have a lower surface. By using the tungsten film as the first metal film 110a and 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 chloride 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 The source electrode 110 and the drain electrode 112 may be 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 by, for example, 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 first etching, and the second metal Then, the first metal film 110b and the second metal film 112b are formed. On the metal film (second metal film 110b and 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 formed by the oxidation. Since the oxide semiconductor film 108 is not in direct contact with the oxide semiconductor film 108, the back This can suppress the diffusion of impurities (especially copper elements) that may get mixed into the panel.

[0044] In addition, an oxygen-excess first insulating layer is formed on the source electrode 110 and the drain electrode 112. a second insulating film 114b formed on the first insulating film 114a; The aluminum oxide film 116 formed on the insulating film 114b and the aluminum oxide film 116 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 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 / ℃ Over 50 x 10 -7 / °C or less (preferably 30 × 10 -7 / ℃ or more 40×10 -7 / ℃ The strain point is 650°C or higher and 750°C or lower (preferably 700°C or higher and 740°C or lower). It is preferable to use a substrate that is (hereinafter referred to as "substrate")

[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), Shrinkage of the substrate caused by heat treatment during the device manufacturing process 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. That's fine.

[0049] Alternatively, 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 formed, or a transistor including the oxide semiconductor film 108 may be formed on another substrate. The resistor 150 may be fabricated and then peeled off and transferred to a flexible substrate. The transistor 15 including the formation substrate and the oxide semiconductor film is peeled off and transferred to a flexible substrate. It is advisable to provide a peeling layer between the

[0050] Furthermore, an underlying insulating film may be provided on the substrate 102. The underlying insulating film may be formed by plasma CV Silicon oxide, silicon oxynitride, aluminum oxide, etc. are deposited by the D method or sputtering method. oxide insulating films such as aluminum, aluminum oxide nitride, hafnium oxide, and gallium oxide; Nitride insulators such as silicon, silicon oxynitride, aluminum nitride, and aluminum oxynitride The membrane may be formed of a membrane, a membrane, or a mixture of these materials.

[0051] Alternatively, the substrate 102 may be subjected to heat treatment. For example, the heat treatment may be performed using high-temperature gas. 650℃ using a GRTA (Gas Rapid Thermal Anneal) device The heat treatment is carried out for 1 to 5 minutes. Inert gases that do not react with the material to be treated by heat treatment, such as rare gases such as fluorine 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 film 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. A copper film 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 104b are The stacked structure of the second gate electrode 04b will be described below, but is not limited to this configuration. A third gate electrode may be further provided on the electrode 104b. 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 films. For example, silicon nitride film, silicon oxynitride film, The first gate insulating film 104 is in contact with the substrate 102 and the gate electrode 104. By using a nitride insulating film as 06a, the insulating film 106a can be formed from 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 This can suppress diffusion of copper elements into the oxide semiconductor film 108.

[0056] In this embodiment, the first gate insulating film 106a is formed by using a plasma CVD method. The silicon nitride film is formed using a 50 nm thick silicon nitride film. For example, a mixture of silane (SiH4) and nitrogen, or a mixture of silane, nitrogen, and ammonia (NH 3) A mixed gas or the like 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, more preferably 100 nm or more and 200 nm or less. It is preferable to use an oxide insulating film having a thickness of 1 μm or less. For example, a silicon oxide film or a gallium oxide film Examples include a silicon oxide film, 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 or yttrium oxide. , 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 high-k materials such as lanthanum oxide are used. This reduces the gate leakage current.

[0059] In this embodiment, the second gate insulating film 106b is formed by plasma CVD to a thickness of 1000 nm. A 200 nm silicon oxynitride film is formed. The plasma CVD method is different from the sputtering method. In comparison, the plasma CVD method can shorten the film formation time. The film thickness variation within the surface is smaller than that of the coating method, and there is no particle contamination. Difficult.

[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 containing oxygen, and to avoid impurities such as water and hydrogen as much as possible. However, in the plasma CVD method, compared with the sputtering method, Therefore, it is difficult to reduce the hydrogen concentration in the film. The insulating film 106b is subjected to a heat treatment (dehydration) for the purpose of reducing, more preferably removing, hydrogen atoms. Hydrogenation or dehydrogenation treatment may be carried out.

[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 a type of heat treatment device. Then, the gate insulating film 106 is subjected to a heat treatment at 650° C. for 1 hour in a vacuum (reduced pressure) atmosphere. Carry out the process.

[0062] The heat treatment device is not limited to an electric furnace, and may be a heat treatment device using heat conduction or heat from a heat source such as a resistance heating element. A device that heats the object to be treated by radiation may be used. For example, a GRTA (Gas Reactor Tank Apparatus) apid Thermal Anneal) equipment, LRTA (Lamp Rapid T RTA (Rapid Thermal Anneal) equipment, etc. The LRTA device can be used with halogen lamps, metal halide lamps, etc. lamp, xenon arc lamp, carbon arc lamp, high-pressure sodium lamp, high-pressure mercury lamp It is a device that heats the object to be treated by radiating light (electromagnetic waves) emitted from a lamp or other lamp. The GRTA device is a device that performs heat treatment using high-temperature gas. An inert gas that does not react with the material to be treated by 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 to 700°C. stomach.

[0063] The heat treatment is carried out in a nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably 1 ppm). m or less, more preferably 10 ppb or less of air), or rare gases (argon, helium However, it is preferable to carry out the treatment under an atmosphere of nitrogen, oxygen, ultra-dry air, or a rare gas. It is preferable that the gas does not contain water, hydrogen, etc. The purity of the element or rare gas is 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, Gate insulating film that has been freed of impurities such as hydrogen and water that cause fluctuations in transistor characteristics 106 can be formed.

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

[0066] Next, an oxide semiconductor film is formed in a position that 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 either 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 has the above-described structure, heat treatment is performed on the oxide semiconductor film 108 in a later manufacturing step. The amorphous oxide semiconductor film may be crystallized by the above-mentioned method. The temperature of the heat treatment is 250°C or higher and 700°C or lower, preferably 400°C or higher, and more preferably The temperature is preferably 500°C or higher, and more preferably 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 Epitaxy) method, or the like. Beam Epitaxy, Plasma CVD, Pulsed Laser Deposition, ALD (A Atomic Layer Deposition (ALD) method or the like 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 method, the atmospheric gas supplied into the processing chamber of the sputtering device is As a result, high-purity rare gases (typically rare gases) from which impurities such as hydrogen, water, hydroxyl groups, or hydrides have been removed are used. For the gas, argon, oxygen, and a mixed gas of a rare gas and oxygen are used as appropriate.

[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. 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 turbomolecular pump with a cold trap may be used. The group is, for example, a compound containing a hydrogen atom, such as a hydrogen molecule or water (H2O) (more preferably a carbon Because of its high pumping capacity, the processing chamber is evacuated using a 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 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 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 mixed atmosphere 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 of the arrow.

[0072] In addition, the oxide semiconductor film 108 has a higher oxygen content than the stoichiometric composition immediately after deposition. It is preferable that the oxide semiconductor film 1 is saturated. When forming a film of O8, it is preferable to form the film under conditions where 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 film formation is performed 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 formed 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 film composition may differ. 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 it depends on the film formation conditions. The composition may be In:Ga:Zn=1:1:0.6-0.8 in 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 prepared in advance. For example, the composition of the oxide semiconductor film 108, which is a thin film, needs to be adjusted. When the atomic ratio is In:Ga:Zn=1:1:1, the metal oxide target The composition may 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 adjusted appropriately 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 metal oxide The relative density of the oxide target is 90% or more and 100% or less, preferably 95% or more, and more preferably Preferably, it is 99.9% or more. By using a metal oxide target with a high relative density, As a result, the formed oxide semiconductor film 108 can be 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 temperature should be 350°C or less. In addition, by heating the substrate at a high temperature during film formation, the crystalline acid 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 semiconductor device for reducing variations in electrical characteristics of a transistor including the oxide semiconductor is also disclosed. It is preferable to have gallium (Ga) as a stabilizer in addition to the above. It is preferable to use tin (Sn) as a stabilizer. It is preferable to have hafnium (Hf) as a stabilizer. It is preferable to use zirconium (Zr) as a stabilizer. It is preferred that the compound has the following structure:

[0078] Other stabilizers include lanthanides such as lanthanum (La) and cerium. (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium Eu, Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), aluminium (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-based oxides, In-La-Zn-based oxides, In-Ce-Zn-based oxides, In-Pr-Zn oxides, In-Nd-Zn oxides, In-Sm-Zn oxides, In-Eu-Zn oxides Oxides, In-Gd-Zn oxides, In-Tb-Zn oxides, In-Dy-Zn oxides 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 Oxides, In-Hf-Ga-Zn oxides, In-Al-Ga-Zn oxides, In-S n-Al-Zn oxide, In-Sn-Hf-Zn oxide, In-Hf-Al-Zn An oxide can be used.

[0080] Here, for example, In-Ga-Zn oxide refers to an oxide containing In, Ga, and Zn as its main components. The ratio of In, Ga, and Zn is not important. 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 ) may be used, where M is selected from Ga, Fe, Mn and Co. In addition, the oxide semiconductor is 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 oxides with an atomic ratio of 2 (= 1 / 2:1 / 6:1 / 3) and their compositions Alternatively, In:Sn:Zn=1:1:1 (=1 / 3) :1 / 3:1 / 3), In:Sn:Zn=2:1:3(=1 / 3:1 / 6:1 / 2) In-Sn with an atomic ratio of In:Sn:Zn=2:1:5 (=1 / 4:1 / 8:5 / 8) It is preferable to use n-Zn oxides or oxides with compositions 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 properties, a material with an appropriate composition can be used. Carrier concentration, impurity concentration, defect density, atomic ratio of metal elements to oxygen, interatomic distance, density, etc. It is preferable to make it appropriate.

[0084] For example, high mobility can be obtained relatively easily with In-Sn-Zn oxides. However, even in In-Ga-Zn oxides, the mobility can be improved by reducing 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, 0.05 can be used as r. The same is true for other oxides.

[0086] The oxide semiconductor film 108 is a CAAC-OS (C Axis Aligned C It is preferable that the film is a crystalline oxide semiconductor film. It's nice.

[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 Microscope (TEM) In the observation image using a microscope, the boundary between the amorphous and crystalline parts in the CAAC-OS film is clearly visible. Furthermore, the grain boundaries in the CAAC-OS film were not clearly observed by TEM. Therefore, the CAAC-OS film is not affected by electron transfer due to grain boundaries. The decrease in mobility is suppressed.

[0088] The crystal part included in the CAAC-OS film has a c-axis that is normal to the surface on which the CAAC-OS film is formed. The three planes are aligned parallel to the normal vector of the wall or surface and perpendicular to the ab plane. It has a square or hexagonal atomic arrangement, and the metal atoms are layered or arranged in a direction perpendicular to the c-axis. In the crystal structure, metal atoms and oxygen atoms are arranged in layers. The orientation of the b-axis may be different. 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 crystals are grown from the surface side of the oxide semiconductor film, The proportion of crystalline parts near the surface may be higher than that near the formation surface. By adding impurities to the AAC-OS film, the crystalline part becomes non-crystalline in the impurity-doped region. It may also crystallize.

[0090] The c-axis of the crystalline 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 surface or the cross-sectional shape of the surface, they may face in different directions. The c-axis direction of the crystalline 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 a transistor using a CAAC-OS film change when irradiated with visible or ultraviolet light. Therefore, the transistor has high reliability.

[0092] When 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 between 100°C and 450°C. 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 approximately vertical. After that, 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°C and 700°C. This method involves first forming a second layer and then aligning the c-axis approximately perpendicular to the surface.

[0093] Note that the oxide semiconductor film 108 may be formed using an oxide semiconductor having crystallinity other than a CAAC-OS film. 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 10 yA / μm or less at room temperature, and , which is extremely small, less than 1zA / μm.

[0096] Alternatively, 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 formed by stacking a first oxide semiconductor layer and a second oxide semiconductor layer. The first oxide semiconductor layer and the second oxide semiconductor layer are made of metal oxides having different compositions. For example, a ternary metal oxide may be used for the first oxide semiconductor layer, and a ternary metal oxide may be used for the second oxide semiconductor layer. The conductor layer may be made of a binary metal oxide. The semiconductor layers may both 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 constituent elements, and the combination of the two is 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=1:1:1, and 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 and the second oxide semiconductor layer that is closer to the gate electrode ( The content ratio of In to Ga in the oxide semiconductor layer on the channel side is 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 conductivity than oxides with a composition of In≦Ga. In addition, the formation energy of oxygen vacancies in Ga is higher than that in In, and the formation energy of oxygen vacancies in Ga is higher than that in In. Since the loss is less likely to occur, oxides with a composition of In≦Ga are different from oxides with a composition of In>Ga. Therefore, the oxide layer with a composition of In > Ga on the channel side has more stable characteristics. A compound semiconductor layer is applied, and an oxide semiconductor layer with a composition of In≦Ga is applied to the back channel side. By doing so, it is possible to further improve 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, a polycrystalline oxide semiconductor, an amorphous oxide semiconductor, or a crystalline oxide semiconductor (e.g. For example, a structure in which CAAC-OS is appropriately combined may be used. An amorphous oxide semiconductor is applied to at least one of the first oxide semiconductor layer and the second oxide semiconductor layer. This reduces the internal and external stresses of the oxide semiconductor, reducing the variations in transistor characteristics. This reduces the amount of oxide film, 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 oxygen vacancies occur easily. Therefore, the oxide semiconductor layer on the channel side is easily converted to n-type. An oxide semiconductor (for example, CAAC-OS) is preferably used.

[0100] In addition, the combination of the composition and the crystallinity when the oxide semiconductor film 108 is stacked is as follows: 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 nitride semiconductor layer, or crystallinity with an atomic ratio of In:Ga:Zn=1:1:1 An oxide semiconductor layer and a crystalline oxide semiconductor with an atomic ratio of In:Ga:Zn=3:1:2 or so Another example is a laminated structure with In:Ga:Zn=3 A crystalline oxide semiconductor layer with an atomic ratio of In:Ga:Zn=1:1:1 or so The crystalline oxide semiconductor layer may have a stacked structure with the crystalline oxide semiconductor layer. An amorphous oxide semiconductor layer having an atomic ratio of In:Ga:Zn=1:1:1 or so, 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 an amorphous oxide semiconductor layer having an atomic ratio of about In:Ga:Zn=3:1:2; 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 treatment is not particularly limited, but may be a polishing treatment (for example, a chemical polishing treatment). Chemical Mechanical Polishing (CMP) A dry etching process, a plasma process, and a CVD process can be used.

[0102] As the plasma treatment, for example, a reverse plasma treatment is used, in which argon gas is introduced to generate plasma. Reverse sputtering is a process in which R is applied to the substrate side under an argon atmosphere. A method of modifying the surface by applying voltage using an F power supply to generate plasma near the substrate. In place of argon, nitrogen, helium, oxygen, etc. may be used. When this 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 on the thickness, and it may be set appropriately depending on the unevenness of the surface on which the oxide semiconductor film 108 is to be formed. .

[0104] After the oxide semiconductor film 108 is formed, excess water contained in the oxide semiconductor film 108 is removed. Heat treatment to reduce or remove (dehydrate or dehydrogenate) oxygen (including water and hydroxyl groups) The conditions for the heat treatment 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 step.

[0105] By this heat treatment, the oxide semiconductor film 108 is converted into an n-type conductive impurity, 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 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 doing so, 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 While slowly cooling from the temperature, high purity oxygen gas, high purity dinitrogen monoxide gas, or ultra pure oxygen gas is added to the same furnace. Dry air (measured using a CRDS (cavity ring-down laser spectroscopy) type dew point meter) When measured, the moisture content is 20 ppm or less (-55°C in terms of dew point), preferably 1 ppm or less , more preferably 10 ppb or less of air) may be introduced. It is preferable that the oxygen gas does not contain water, hydrogen, etc. The purity of nitrogen gas or nitrous oxide 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 the main component material of the oxide semiconductor film 8, the oxide semiconductor film 108 is highly It can be purified and made into type i (intrinsic).

[0107] The heat treatment for dehydration or dehydrogenation is the same as other heat treatments in the fabrication process of the transistor 150. It may also serve as the following.

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

[0109] The first metal film 109a may be 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 sputtering. A tungsten film with a thickness of 50 nm is used.

[0110] The first metal film 109a may have a laminated structure. 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 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 make it n-type, or a material that diffuses into the oxide semiconductor film 108 to make it 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 into the oxide semiconductor film 108 (so-called barrier metal material) It is preferable to use

[0112] The second metal film 109b is preferably a film containing copper. Copper alloys containing a few weight percent of aluminum, gold, silver, zinc, tin, nickel, etc. may also be used. In this embodiment, the second metal film 109b is formed by sputtering. 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, 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, and the second metal film 1 Then, a second 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 solution 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. 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 located inside the side surface of the block 141. It may also be a recessed shape.

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

[0119] The resist mask 141 can be removed by a wet method using a remover, or by a polishing method. Dry removal methods such as plasma treatment or a combination of these methods are used. It is possible.

[0120] Next, on the first metal film 109a, the second metal film 110b, and the second metal film 112b, 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 second 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 outside 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 can be 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 mixed gas of SF6 and O2 or a mixed gas of SF6 and BCl3, etc. It can be used.

[0127] When etching the first metal film 109a and the third metal film 109c, 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 It is possible to obtain a condition in which the oxide semiconductor film 108 is etched without being etched at all. It is difficult to etch the first metal film 109a and the third metal film 109c. The conductive film 108 is partially etched to form an oxide semiconductor film 108 having a groove (depression). 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 removed. and a source electrode 110 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 compound semiconductor film 108 (more specifically, the back channel side) is connected to the 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 resist mask 142 can be removed by the same method as that 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 by, for example, oxygen plasma treatment or dilute hydrofluoric acid treatment. By carrying out such cleaning, the source electrode 110 and the drain Etching gas components 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, and the oxide semiconductor film 108 can be made more pure. 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 strain 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 plasma CVD or sputtering. It can be silicon oxide film, gallium oxide film, aluminum oxide film, silicon oxynitride film An oxide insulating film such as an aluminum oxide nitride film or 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 oxygen-excess 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 formed by a plasma CVD method. The silicon oxynitride film is formed. The film formation conditions for the first insulating film 114a are, for example, SiH4 The gas flow ratio of SiH4 and N2O was set to 20sccm:3000sccm, and the pressure The pressure was set to 200 Pa, the RF power supply power (power output) was set to 100 W, and the substrate temperature was set 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, just 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, the daughter ions, or the 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 is possible to use a gas cluster ion beam 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 (for example, 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 5x10 or more 16 ions / cm 2 Preferably, the acid The oxygen content in the first insulating film 114a after the oxygen introduction process is determined by the chemical composition of the first insulating film 114a. It is preferable that the oxygen concentration is greater than the stoichiometric composition. The oxygen injection depth varies depending on the injection conditions. It should be controlled 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. Therefore, the oxygen concentration in the oxide insulating film is measured by SIMS (Secondary Ion Microscopy). It is difficult to accurately estimate the amount of 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 applies to the case where the gas 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 by methods such as SIMS. Therefore, by measuring these concentrations, the oxide It is possible to more accurately estimate the oxygen concentration in an insulating film in contact with a semiconductor film or in an oxide semiconductor film. Therefore, by measuring the concentrations of these, it is possible to determine the amount of the oxide semiconductor film that is in contact with the oxide semiconductor film. Alternatively, it may be determined whether or not oxygen has been added to the insulating film.

[0144] In this way, the introduction of oxygen 145 forms an oxygen-excess first insulating film 114a. By using the oxygen-excess first insulating film 114a, the thermal treatment in the manufacturing process of the transistor can be performed. Oxygen can be supplied to the oxide semiconductor film 108 by solid-phase diffusion due to the oxidation process. Furthermore, the introduction of oxygen 145 allows the oxide semiconductor Oxygen may be introduced into the film 108 .

[0145] Next, a 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 plasma CVD or sputtering. 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 50 nm or more and 500 nm or less. It's nice.

[0147] In this embodiment, the second insulating film 114b is formed by plasma CVD using a 370 nm thick film. The second insulating film 114b is formed under the conditions of, for example, SiH 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°C is sufficient.

[0148] When the first insulating film 114a and the second insulating film 114b are made of the same material, Therefore, the interface between the first insulating film 114a and the second insulating film 114b may not be clearly visible. Therefore, in this embodiment, the first insulating film 114a and the second insulating film 114b The interface between the two is shown by a dashed line.

[0149] The second insulating film 114b is preferably free from water, hydrogen, etc., as is the first insulating film 114a. Therefore, in this embodiment, after the film formation, The second insulating film 114b is subjected to a heat treatment (dehydration or dehydration) for the purpose of removing hydrogen atoms. The process is then carried out.

[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. In this embodiment, the heat treatment is performed at 350° 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 sputtering, vapor deposition, CVD, or the like. It is preferable that the thickness of the aluminum film 115 is 3 nm or more and 10 nm or less. In this embodiment, a 5 nm thick aluminum film is formed by sputtering. Form a film.

[0153] The aluminum film 115 formed on the second insulating film 114b is to be subjected to oxygen introduction treatment later. The aluminum oxide film is formed by the treatment and 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. The membrane has a high blocking effect (blocking effect) that prevents both water and oxygen from passing through. It has a certain 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 formed through the aluminum film 115. Oxygen may be introduced into a part of the film. This compensates for oxygen that may be desorbed by heat treatment and also increases the oxygen content 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 can 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 can be formed as follows: It does not need to contain oxygen in accordance with the stoichiometric composition 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 or more and 3.5 or less. In addition, if the aluminum oxide film 116 is conductive, Resistivity ρ is 10 10 Ω m or more 10 19 Ω·m or less, preferably 10 10 Ω m or more 1 0 18 Ω·m or less, 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 This can improve productivity.

[0159] After the oxygen 147 is introduced into the aluminum film 115, a heat treatment may be performed. The heat treatment removes oxygen contained in the first insulating film 114a or the second insulating film 114b. 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 planarization 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 unevenness 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 resins, polyamide resins, and epoxy resins. In addition to the above organic materials, low-k materials and siloxane resins can also be used. It is possible to use a laminate of 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, when forming the source electrode and the drain electrode, the back layer of the oxide semiconductor film is 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 suppressed. 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. Data can be provided.

[0163] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0164] (Embodiment 2) In this embodiment mode, a modification of the semiconductor device shown in Embodiment 1 and a semiconductor device shown in Embodiment 1 will be described. A manufacturing method different from the manufacturing method of the semiconductor device described above will be described with reference to FIGS. 6 to 8. 1 to 5, the same reference numerals 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. 6(B) 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 electrode A gate insulating film 206 is formed on the gate electrode 204, and 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 has a first metal film 210a, a second metal film The second metal film 210b is made of the first metal film 210c. The source electrode 21 is formed in an area inside the end of the third metal film 210a and the end of the third metal film 210c. The drain electrode 212 is made of a first metal film 210a, a second metal film 212a, and a third metal film 210b. The second metal film 210c and the third metal film 212c.

[0167] The gate electrode 204 is divided into 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 also 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 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 low-resistance gate electrode 204. By providing the gate electrode 204a, the substrate 102 and the copper film used as the second gate electrode 204b and / or to improve the adhesion of 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 206b. 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, or the like is used. The second gate insulating film 206b can be formed on the oxide semiconductor film 108 to be formed later. It is sufficient if the film has a function of supplying oxygen to the substrate. 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 108 is formed later. 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. In this case, a copper film is used as the second metal film 210b.

[0172] In this way, 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, signal delay caused by wiring resistance can be reduced. In addition, the source electrode 210 and the drain electrode 212 used in the transistor 250 can be suppressed. By using a material containing no copper element for the rain electrode 212, the oxide semiconductor film 10 This is effective in that the copper element, which may diffuse into the electrode 8, can be placed 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, it has an excellent effect of reducing manufacturing costs.

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

[0174] <Method 2 for manufacturing semiconductor device> First, a gate electrode 204, a gate insulating film 206, and an oxide semiconductor film 101 are formed on a substrate 102. 108 is formed. Note that the gate electrode 204, the gate insulating film 206, and the oxide semiconductor film 108 are 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 a gate insulating film 108 are formed on the oxide semiconductor film 108. , a first metal film 209a which will be a source electrode, a drain electrode, and a signal line, and a second metal film 209b which will be a second metal film 209c which will be a source electrode, a drain electrode, and a signal line. A metal film 209b is formed (see FIG. 7(A)).

[0175] The first metal film 209a is made of tungsten, tantalum, titanium, and 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 sputtering. A tungsten film with a thickness of 50 nm is used.

[0176] The first metal film 209a may have a laminated structure. 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 209a is made of tungsten nitride. one or more elements selected from the group consisting of tantalum nitride, titanium nitride, and molybdenum nitride 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 make it n-type, or a material that diffuses into the oxide semiconductor film 108 to make it n-type The first metal film 209a is made of a material that does not cause the metal to be broken. It is desirable 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. Copper alloys containing a few weight percent of aluminum, gold, silver, zinc, tin, nickel, etc. may also be used. In this embodiment, the second metal film 209b is formed by sputtering. 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 described in Embodiment 1. and methods.

[0181] Next, a part of the second metal film 209b is removed by a first etching, 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 solution 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. 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 way, 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 metal film 0b (see FIG. 7(D)).

[0186] The resist mask 241 can be removed by the same method as that of the resist mask 141 shown in Embodiment 1. This can be done by the same method as in the removal method of the first.

[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 second 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 can be 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 mixed gas of SF6 and O2 or a mixed gas of SF6 and BCl3, etc. It can be used.

[0193] In addition, when etching the first metal film 209a and the third metal film 209c, 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 It is possible to obtain a condition in which the oxide semiconductor film 108 is etched without being etched at all. It is difficult to etch the first metal film 209a and the third metal film 209c. The conductive film 108 is partially etched to form an oxide semiconductor film 108 having a groove (depression). 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 the resist mask 241. This can be done by the following method.

[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 component 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 even more pure.

[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 below the strain 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, a first insulating film 114a and a 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 oxide insulating film 118 can be formed by referring to the steps described in Embodiment 1. Cut.

[0202] In this way, the configuration of the source electrode 210 and the drain electrode 212 of the transistor 250 The signal line 232 in the signal line region 260 has a different configuration. By electrically connecting a signal line 232 using a copper film to the signal line 212, the signal due to the wiring resistance can be reduced. In addition, the source electrode 210 used in the transistor 250 can be Furthermore, by using a material containing copper for the drain electrode 212, the oxide semiconductor This is effective in that copper elements that may diffuse into the film 108 can be located at a distance. 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] As described above, the configurations, methods, etc. shown in this embodiment may be different from the configurations, methods, etc. shown in other embodiments. They can be used in appropriate combinations.

[0204] (Embodiment 3) The transistors or signal lines illustrated in Embodiments 1 and 2 may be used to In addition, a display device having the above-described 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 portion 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. The pixel section 302, the source driver circuit section 304, and the gate driver circuit section 305 are connected to the pixel section 302. The second substrate 301 is provided on the path portion 306. The gate driver circuit section 304 and the gate driver circuit section 306 are attached to the first substrate 300 by a sealing material. 312 and the second substrate 301, and is sealed together with the display element.

[0206] In addition, in FIG. 9, the area surrounded by the seal material 312 on the first substrate 300 The pixel section 302, the source driver circuit section 304, and the gate driver circuit section 305 are arranged in a region different from the pixel section 302. An FPC terminal portion 308 (FPC: Flexible Printed Circuit) electrically connected to the circuit portion 306 The FPC terminal section 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 applied to the circuit section 306 are supplied by an FPC 316 .

[0207] 9, a pixel section 302, a source driver circuit section 304, a gate driver circuit section 306, a A signal line 310 is connected to each of the path portion 306 and the FPC terminal portion 308. The various signals and potentials supplied by 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] 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 portion 302. For example, only the gate driver circuit section 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. is formed is used. A substrate (for example, a drive 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 of the following: (Chip On Glass) method, wire bonding method, or TAB (Tap e Automated Bonding methods 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 attached to 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 shall be 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 Embodiment 2 can be applied to the semiconductor device. The case where the transistor exemplified in Embodiment 2 is applied will be described.

[0213] Further, examples of display elements provided in the display device include liquid crystal elements (also called liquid crystal display elements), Light-emitting elements (also called light-emitting display elements) can be used. This category includes elements whose brightness is controlled by the Fluorescent (EL) and organic light-emitting diodes (OLEDs). Electronic inks and other A display medium whose contrast changes by electrical action 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 FIGS. 10 and 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 portion 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 the terminal of the FPC 316 and the anisotropic conductive film 38 0.

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

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

[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 can be changed as needed. 10 and 11, the gate driver circuit section 306 can Although not shown, the connection destination or connection method is different, but the source driver circuit unit 304 The same configuration can be used.

[0219] Also, in FIGS. 10 and 11, transistors 350 and 352, The signal line 310 is connected to the transistor 250 and the signal line 23 shown in the previous 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 up of a first metal film, a second metal film, and a third metal film. The metal film is one or more 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 way, the transistor 350 and the transistor 352 do not use a copper film. The source electrode and the drain electrode are configured in a structure in which 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, a stable electric 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 a protective insulating film 3 An aluminum oxide film is used as the insulating film 364 and the protective insulating film 36. The layer 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. As a result, oxygen can be supplied to the oxide semiconductor film.

[0226] The aluminum oxide film provided as the protective insulating film 366 is resistant to impurities such as hydrogen and water, and It has a high blocking effect that prevents both oxygen and oxygen from passing through the membrane. The aluminum film contains impurities such as hydrogen and water, which are factors that cause fluctuations during and after the manufacturing process. The contamination of the oxide semiconductor film with oxygen, which is the main component of the oxide semiconductor film, It functions as a protective film that prevents 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-resistant resins such as amide resins, benzocyclobutene resins, polyamide resins, and epoxy resins In addition, an 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 transistors 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. A conductive film 370a is provided at a position overlapping with a channel forming region of the compound 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 in a position overlapping with the channel formation region of the oxide semiconductor film, This makes it possible to reduce the amount of change in the threshold voltage of the transistor 352 before and after the BT test. The conductive film 370a may have the same potential as the gate electrode of the transistor 352. However, it may be different 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, prevents the external electric field from reaching the inside (transistor). (especially the function of preventing static electricity from affecting the circuit part including resistor 352) 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 with 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 top, and 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, and various display elements can be used. can be used.

[0232] The display device shown in FIG. 10 is an example of a liquid crystal display device that uses 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 that function as alignment layers. An insulating film 410 and an insulating film 412 are provided. The counter electrode 404 is provided 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 provided to control the film thickness (cell gap) of the liquid crystal layer 406. A spherical spacer may also be used.

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

[0235] In addition, when the in-plane switching method is adopted, a 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, and when the temperature of cholesteric liquid crystal is increased, the cholesteric The blue phase appears just before the transition from the black phase to the isotropic phase. Therefore, 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. The orientation treatment is unnecessary because the liquid crystal display has a short rotational angle and is optically isotropic, and the viewing angle dependency is small. Since there is no need to provide an alignment film, rubbing treatment is also unnecessary. This can prevent electrostatic damage caused by the electrostatic discharge, and can prevent defects and damage to the liquid crystal display device during the manufacturing process. This makes it possible to improve the productivity of liquid crystal display devices. The electrical characteristics of transistors using a nitride semiconductor film are affected by static electricity. Therefore, the transistor using an oxide semiconductor film may be used. It is more effective to use a blue phase liquid crystal material in a liquid crystal display device having a resistor.

[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 ​​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 The capacitance is set to be able to hold charge for a predetermined period, taking into consideration factors such as the current flowing through the capacitor. The size can 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 electrode is suppressed, A storage capacitor having a capacitance of 1 / 3 or less, preferably 1 / 5 or less, of the capacitance 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 when 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 therefore can be driven at high speed. For example, by using such a transistor capable of high-speed driving 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 can be formed on a single substrate, such as a silicon wafer, as a separate driving circuit. Therefore, it is not necessary to use a semiconductor device formed by a semiconductor device, and the number of parts of the semiconductor device can be reduced. In addition, by using a transistor that can be driven at high speed in the pixel portion, High quality images can be provided.

[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 wires containing copper. There is little signal delay or the like that can be 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 Crystal id Crystal) mode, AFLC (AntiFerroelectric Li You can use modes such as quid Crystal.

[0242] In addition, normally black type liquid crystal display devices, for example, those employing vertical alignment (VA) mode The liquid crystal display device may be a transmission type. For example, MVA (Multi-Domain Vertical Alignment) mode, PVA (Patterned Vertical Alignment) mode It can also be applied to VA type liquid crystal display devices. A type of LCD is a type of LCD that controls the arrangement of liquid crystal molecules in the LCD panel. In VA type LCD devices, the liquid crystal molecules are aligned with the panel surface when no voltage is applied. It is a method of vertical orientation. Also, pixels are divided into several regions (subpixels). The molecules are 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. Circular polarization by the substrate may be used. Also, a backlight, a sidelight, etc. may be used as a 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 (R is red, G is green, and B is blue). For example, RGBW (W is white) ), or RGB plus one or more colors such as yellow, cyan, magenta, etc. 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 also be applied to monochrome display devices. It is also possible to do so.

[0245] In addition, a light-emitting device using electroluminescence is used as a display element included in the display device. The light-emitting element using 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, when a voltage is applied to the light-emitting element, electrons and positive electrodes are released from a pair of electrodes. The holes are then injected into a layer containing a light-emitting organic compound, allowing a current to flow. The recombination of carriers (electrons and holes) causes light-emitting organic compounds to form excited states. The excited state is formed, and light is emitted when the excited state returns to the ground state. Such a light-emitting element is called a current-excited 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 are made of a light-emitting layer in which particles of light-emitting material are dispersed in a binder. The emission mechanism is a donor- The thin-film inorganic EL element is an acceptor recombination type luminescence element. The luminescent layer is sandwiched between dielectric layers. The structure is sandwiched between electrodes, and the light emission mechanism is the inner-shell electron transition of the metal ion. 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 the 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 to the substrate. Top emission, bottom emission, and both the substrate side and the opposite side of the substrate. There are light emitting elements with a double-sided emission structure that emits light from both sides, and light emitting elements 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 laminating a conductive film 370b, an electroluminescent layer 452, and an upper electrode 454. However, it is not limited to the configuration shown in the figure. In addition, the configuration of the light emitting element 450 can be changed as appropriate.

[0250] The partition wall 456 is formed using an organic insulating material or an inorganic insulating material. 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 to the planarization insulating film 368 and the conductive film 370b. and irradiating a desired area with light to form an opening in a part of the conductive film 370b. The sidewall of the opening can be formed as an inclined surface having a continuous curvature.

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

[0252] The upper electrode 454 is provided to prevent oxygen, hydrogen, water, carbon dioxide, etc. from entering the light emitting element 450. A protective film may be formed on the partition wall 456. The protective film may be a silicon nitride film, a nitride film, or the like. 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 this way, a protective film (paste) with high airtightness and low outgassing is used to prevent exposure to the outside air. Packaging (enclosure) with a covering material (such as a laminated film or UV-curable resin film) It is preferable that

[0253] Filler 458 can be an inert gas such as nitrogen or argon, or an 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 (λ / 4 plate, λ / 2 plate), color filters, and other optical films are provided as needed. Alternatively, an anti-reflection film may be provided on the polarizing plate or the circular polarizing plate. Anti-glare treatment can be applied to further diffuse reflected light and reduce glare.

[0255] 10 and 11, the first substrate 300 and the second substrate 301 are In addition to a glass substrate, a flexible substrate can also be used. For example, a transparent plastic substrate can be used. As for plastic, FRP (Fibre Plastic) 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. A port can also be used.

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

[0257] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiment modes. It is Noh.

[0258] (Fourth embodiment) The semiconductor device disclosed in this specification can be applied to various electronic devices (including gaming 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, mobile phones (also called telephone devices), portable game consoles, personal digital assistants (PDAs), mobile terminals (smartphones) (including smartphones, tablet PCs, etc.), sound reproduction equipment, 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 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, stable electricity can be obtained. A notebook-type personal computer with low signal delay due to wiring resistance. It can be used as a data.

[0260] FIG. 12B shows a personal digital assistant (PDA), and a main body 3021 includes a display unit 3023 and , an external interface 3025, an operation button 3024, etc. are provided. The semiconductor device shown in any of the above embodiments has a stylus 3022 as an accessory. By applying the device to the display unit 3023, it is possible to obtain more stable electrical characteristics and reduce wiring resistance. This makes it possible to provide a personal digital assistant (PDA) with little 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 It consists of two housings, housing 2701 and housing 2703. 03 is integrated with a shaft portion 2711, and performs opening and closing operations around the shaft portion 2711. This configuration allows the device to operate like a paper book. .

[0262] The housing 2701 incorporates a display unit 2705, and the housing 2703 incorporates a display unit 2707. 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 minimizes signal delays caused by wiring resistance. A semi-transmissive or reflective liquid crystal display device is used as the display unit 2705. In this case, it is expected that the device will be used in relatively bright conditions, so a solar cell will be installed and the device will be The battery may be configured to generate power 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. The operation keys 2723 can be used to turn pages. A keyboard and a pointing device may be provided on one side. On the back or side 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 also be configured so that

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

[0265] FIG. 12(D) shows a mobile phone, which is composed of two housings, a housing 2800 and a housing 2801. The housing 2801 contains a display panel 2802, a speaker 2803, a microphone, Phone 2804, pointing device 2806, camera lens 2807, 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, etc. The semiconductor device described in any 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. This makes it possible to create a mobile phone with little signal delay.

[0266] The display panel 2802 is equipped with a touch panel, and the image displayed in FIG. The multiple operation keys 2805 are shown by dotted lines. A boost circuit is also implemented to boost the input voltage to the voltage required for 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 lens 2802, allowing video calls. The speaker 2803 and microphone 2804 are not limited to voice calls, but can also be used for video calls. 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 overlapped 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 functions, TV reception functions, 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 of the above embodiments is configured by a display portion ( By applying it to A) 3057 and display (B) 3055, it has stable electrical characteristics. Furthermore, the digital video camera can be one with little signal delay caused by wiring resistance.

[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. The display portion 9603 displays images. In addition, the housing 9601 is supported by a stand 9605. The semiconductor device described in any of the above embodiments is configured as follows: By applying this technology, it has stable electrical characteristics and reduces signal delay caused by wiring resistance. The television device may be a non-audio-visual device.

[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 operation device. A display unit may be provided to display information output from the device.

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

[0274] FIG. 13 shows an example of a tablet terminal, and FIGS. 13(A) to 13(C) show: FIG. 13(D) shows a tablet terminal 5000, and FIG. 13(E) 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. 13(D) shows a front view of the tablet terminal 6000. .

[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 connection terminal 5012. It is composed of a connector 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, 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 housing 5001 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 sound 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, a second housing 6002, and a Housing 6003, hinge portion 6005, first display portion 6007, second display portion 6009, 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 unit The first display unit 6007 and the second display unit 6009 are incorporated in the second housing 6003. The second display unit 6009 uses the first display unit 6007 as a display panel, for example. The second display unit 6009 is a touch panel. Check the icon 6017, and then select the icon 6019 displayed on the second display unit 6009. displays a keyboard 6021 (actually, a keyboard image displayed on the second display unit 6009). It is possible to select an image, input characters, etc. using the first 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. That's 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 The first display unit 6007 is incorporated in the housing 6001, and the second display unit 6008 is incorporated in the housing 6003. By combining the first display unit 6007 and the second display unit 6009, This is preferable because it can protect the surface of the 009 (for example, a plastic substrate, etc.).

[0281] The first housing 6001 and the second housing 6003 can be separated by a hinge part 6005. It is also possible to use a configuration that allows the driver to change the vehicle (so-called convertible type). 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 because it broadens the range of use.

[0282] Also, a first camera 6013 and a second camera 6015 are used to capture 3D images. You can also do this.

[0283] The tablet terminal 5000 and the tablet terminal 6000 transmit information wirelessly. For example, the desired information can be received by connecting to the Internet or the like wirelessly. It is also possible to purchase and download the information.

[0284] Furthermore, the tablet terminal 5000 and the tablet terminal 6000 can display various information (static information, Functions for displaying still images, videos, text images, etc., calendars, dates, or 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 functions such as controlling processing by various software (programs). It also features a light sensor that can optimize the display brightness according to the amount of external light, and a A detection device such as a sensor for detecting tilt, such as a color sensor or acceleration sensor, may be built in.

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

[0286] This embodiment mode can be implemented by being appropriately combined with the configurations described in other embodiment modes. It is Noh. [Explanation of symbols]

[0287] 102 Circuit Board 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 Planarization 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 boards 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 transistors 360 terminal electrode 360a First metal film 360b Second metal film 360c Third Metal Film 364 Insulating Film 366 Protective insulating film 368 Planarization 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 elements 452 Electroluminescent layer 454 Upper electrode 456 Bulkhead 458 Filling material 2700 e-books 2701 Housing 2703 Housing 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 tablet devices 6001 Case 6003 Housing 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 Housing 9603 Display section 9605 Stand

Claims

1. A liquid crystal display device having a transistor in a pixel portion, a first conductive layer that functions 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 disposed above the first insulating layer and including a channel formation region of the transistor; a second conductive layer having a region disposed above the oxide semiconductor layer and functioning as a source electrode; a third conductive layer having a region disposed 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 that functions 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 disposed above the first insulating layer and including a channel formation region of the transistor; a second conductive layer having a region disposed above the oxide semiconductor layer and functioning as a source electrode; a third conductive layer having a region disposed above the oxide semiconductor layer and functioning as a drain electrode; the first insulating layer includes a first film containing nitrogen and silicon, and a second film having a region disposed above the first film and containing oxygen and silicon; 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 claim 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