Display device

Abstract

To provide a display device including a pixel part and a protection circuit outside the pixel part, in which the function of the protection circuit can be enhanced to stabilize the operation.SOLUTION: A protection circuit includes first to fourth transistors. A gate and a first terminal of the first transistor 740a are electrically connected to a second wire 650, and a second terminal of the first transistor is electrically connected to a first wire 651. A gate and a second terminal of the second transistor 740c are electrically connected to the first wire 651 and a first terminal of the second transistor is electrically connected to the second wire. A gate and a second terminal of the third transistor 740d are electrically connected to the first wire and a first terminal of the third transistor is electrically connected to the second wire. A gate and a first terminal of the fourth transistor 740b are electrically connected to the second wire and a second terminal of the fourth transistor is electrically connected to the first wire.SELECTED DRAWING: Figure 28

Description

[Technical field]

[0001] The present invention relates to a display device using an oxide semiconductor. [Background technology]

[0002] As typified by liquid crystal display devices, thin film transistors formed on flat plates such as glass substrates They are made of amorphous silicon and polycrystalline silicon. Thin-film transistors using GaN have low field-effect mobility, but they are suitable for enlarging the area of ​​glass substrates. On the other hand, thin film transistors using polycrystalline silicon have a field effect mobility of Although it is expensive, it requires a crystallization process such as laser annealing, which is necessary for enlarging the area of ​​glass substrates. It has the characteristic that it is not necessarily suitable for all applications.

[0003] In response to this, thin-film transistors are being fabricated using oxide semiconductors, and they are being used in electronic devices and optical devices. For example, zinc oxide (ZnO) is used as an oxide semiconductor film. In addition, thin-film transistors are fabricated using In-Ga-Zn-O oxide semiconductors, and image display is realized. The technology used for the switching element of the device is disclosed in Patent Document 1 and Patent Document 2. . [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-123861 A [Patent Document 2] JP 2007-96055 A Summary of the Invention [Problem to be solved by the invention]

[0005] Thin film transistors that use oxide semiconductors for the channel formation region use amorphous silicon. The operating speed is faster than that of thin-film transistors that use polycrystalline silicon. The manufacturing process is simpler than that of the conventional semiconductor laser. By doing so, it is possible to produce thin-film transistors with high field-effect mobility even at low temperatures below 300°C. It is possible to create a

[0006] In order to take advantage of the characteristics of display devices using oxide semiconductors, which have excellent operating characteristics and can be manufactured at low temperatures, In addition, a display device using an oxide semiconductor requires a protection circuit or the like having a suitable structure. It is important to ensure security.

[0007] An object of one embodiment of the present invention is to provide a structure suitable for a protection circuit.

[0008] One embodiment of the present invention is a semiconductor device including an oxide semiconductor, an insulating film, and a conductive film stacked thereon, and used for various applications. An object of the present invention is to improve the function of a protection circuit and stabilize the operation of a display device. [Means for solving the problem]

[0009] One embodiment of the present invention is a semiconductor memory device in which a protection circuit is formed using a nonlinear element including an oxide semiconductor. This nonlinear element is made up of oxide semiconductors with different oxygen contents. It has been made.

[0010] In one exemplary embodiment of the present invention, scanning lines and signal lines are provided crossing each other on a substrate having an insulating surface. The pixel electrodes are arranged in a matrix, and the pixel region is made of an oxide semiconductor. The pixel portion is a display device having a nonlinear element formed in a first oxide semiconductor layer. The thin film transistor in the pixel portion has a scanning line forming region. a gate electrode connected to the line; a first wiring layer connected to the signal line and in contact with the first oxide semiconductor layer; A second wiring layer is connected to the pixel electrode and in contact with the first oxide semiconductor layer. A nonlinear element is provided between the signal input terminal and the pixel section. The present invention relates to a gate electrode, a gate insulating layer covering the gate electrode, and a gate insulating layer. A pair of first wiring layers and a second oxide semiconductor layer are laminated on each other, and the first wiring layers and the second oxide semiconductor layer are laminated on each other. and a second wiring layer, and a gate insulating layer overlapping at least the gate electrode, and the first wiring layer and the second wiring layer. The first oxide semiconductor layer is in contact with the side surface of the conductive layer in the wiring layer and the side surface and the top surface of the second oxide semiconductor layer. The gate electrode of the nonlinear element is connected to a scanning line or a signal line, The first wiring layer or the second wiring layer of the nonlinear element is such that the potential of the gate electrode is The third wiring layer connects the gate electrodes to the gate electrodes so that a voltage is applied to the layer.

[0011] In one exemplary embodiment of the present invention, scanning lines and signal lines are provided crossing each other on a substrate having an insulating surface. The pixel electrode is arranged in a matrix, and a protection circuit is provided in the outer region of the pixel electrode. The pixel portion is a thin film in which a channel formation region is formed in a first oxide semiconductor layer. The thin film transistor in the pixel portion has a gate electrode connected to a scanning line. a first wiring layer connected to the signal line and in contact with the first oxide semiconductor layer; A second wiring layer is provided in contact with the nitride semiconductor layer. and a protection circuit connecting the signal line and the common line. The protection circuit includes a gate electrode, a gate insulating layer covering the gate electrode, and a gate insulating film. a pair of a gate electrode and a conductive layer and a second oxide semiconductor layer are stacked on the gate electrode and the conductive layer and the second oxide semiconductor layer are stacked on the gate electrode and the second oxide semiconductor layer. The first wiring layer and the second wiring layer, and a gate insulating layer overlapping at least the gate electrode and the first wiring layer. A side surface portion of the conductive layer in the line layer and the second wiring layer, and a side surface portion and a top surface portion of the second oxide semiconductor layer The nonlinear element has a first oxide semiconductor layer in contact with the first oxide semiconductor layer. The port electrode and the first wiring layer or the second wiring layer are connected by a third wiring layer.

[0012] Here, the oxygen concentration of the first oxide semiconductor layer is higher than the oxygen concentration of the second oxide semiconductor layer. That is, the first oxide semiconductor layer is an oxygen-excess type, and the second oxide semiconductor layer is an oxygen-excess type. The electrical conductivity of the first oxide semiconductor layer is lower than that of the second oxide semiconductor layer. The first oxide semiconductor layer has an amorphous structure, and the second oxide semiconductor layer has a non-crystalline structure. The crystalline structure may contain nanocrystals.

[0013] The ordinal numbers such as 1st and 2nd are used for convenience and do not indicate the order of steps or stacking. In addition, the specific names used in this specification are not intended to identify the invention. This does not indicate the

[0014] In this specification, a semiconductor device formed using an oxide semiconductor film containing In, Ga, and Zn The semiconductor film is also referred to as an "IGZO semiconductor film" and the semiconductor layer is also referred to as an "IGZO semiconductor layer." Effect of the Invention

[0015] According to one embodiment of the present invention, a protection circuit is formed using a nonlinear element using an oxide semiconductor. As a result, it is possible to obtain a display device having a structure suitable for a protection circuit. In a connection structure between a first oxide semiconductor layer and a wiring layer, a second oxide semiconductor layer has a higher electrical conductivity than a first oxide semiconductor layer. By providing a region where the second oxide semiconductor layer has a high conductivity, the This allows for stable operation, improving the function of the protection circuit and stabilizing operation. It is possible to plan this. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram illustrating a positional relationship between a signal input terminal, a scanning line, a signal line, a protection circuit including a nonlinear element, and a pixel portion, which configure a display device. [Diagram 2] FIG. 13 illustrates an example of a protection circuit. [Diagram 3] FIG. 13 illustrates an example of a protection circuit. [Figure 4] FIG. 4 is a plan view showing an example of a protection circuit. [Diagram 5] FIG. 1 is a cross-sectional view showing an example of a protection circuit. [Figure 6] 1A to 1C are cross-sectional views illustrating a manufacturing process of a protection circuit. [Figure 7] 1A to 1C are cross-sectional views illustrating a manufacturing process of a protection circuit. [Figure 8] 1A to 1C are cross-sectional views illustrating a manufacturing process of a protection circuit. [Figure 9] 1A to 1C are cross-sectional views illustrating a manufacturing process of a protection circuit. [Figure 10] FIG. [Figure 11] FIG. 1 is a block diagram illustrating a semiconductor device. [Figure 12] FIG. 2 illustrates a configuration of a signal line driver circuit. [Figure 13] 4 is a timing chart illustrating the operation of the signal line driver circuit. [Figure 14] 4 is a timing chart illustrating the operation of the signal line driver circuit. [Figure 15] FIG. 2 is a diagram illustrating a configuration of a shift register. [Figure 16]15 is a diagram for explaining a connection configuration of the flip-flop shown in FIG. 14. [Figure 17] 1A and 1B are a top view and a cross-sectional view illustrating a semiconductor device of an embodiment. [Figure 18] 1 is a cross-sectional view illustrating a semiconductor device according to an embodiment; [Figure 19] 1 is a diagram illustrating a pixel equivalent circuit of a semiconductor device according to an embodiment; [Figure 20] 1A to 1C illustrate a semiconductor device according to an embodiment; [Figure 21] 1A and 1B are a top view and a cross-sectional view illustrating a semiconductor device of an embodiment. [Figure 22] 1A and 1B are diagrams illustrating examples of usage of electronic paper. [Diagram 23] FIG. 1 is an external view showing an example of an electronic book. [Figure 24] FIG. 1 is an external view showing an example of a television device and a digital photo frame. [Diagram 25] FIG. 1 is an external view showing an example of a gaming machine. [Figure 26] FIG. 1 is an external view showing an example of a mobile phone. [Figure 27] FIG. 4 is a plan view showing an example of a protection circuit. [Figure 28] FIG. 4 is a plan view showing an example of a protection circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] An embodiment of the present invention will be described below with reference to the drawings. The invention is not limited to the following description, and the form may be changed without departing from the spirit and scope of the invention. It will be readily understood by those skilled in the art that various modifications may be made to the mode and details of the present invention. The present invention should not be construed as being limited to the description of the embodiments shown below. In the configuration of the present invention, the same reference numerals are used in common between different drawings to indicate the same parts.

[0018] (Embodiment 1) This embodiment is one aspect of a display device in which a pixel section and a protection circuit including a nonlinear element are formed in the periphery of the pixel section. The following description will be given with reference to the drawings.

[0019] FIG. 1 shows a display device that includes a signal input terminal, a scanning line, a signal line, and a protection circuit including a nonlinear element. 1 is a diagram for explaining the positional relationship between the scanning lines 13 and the pixel portion on a substrate 10 having an insulating surface. The signal lines 14 cross each other to form a pixel section 17 .

[0020] The pixel section 17 is configured with a plurality of pixels 18 arranged in a matrix. A pixel transistor 19, a storage capacitor 20, and a pixel electrode 21 connected to the line 13 and the signal line 14 are It is composed of including.

[0021] In the pixel configuration illustrated here, one electrode of the storage capacitor 20 is connected to the pixel transistor 19 The pixel electrode 21 is connected to the capacitance line 22, and the other electrode is connected to the capacitance line 23. While driving display elements (liquid crystal elements, light-emitting elements, contrast media (electronic ink), etc.) The other electrodes of these display elements are connected to a common terminal 23.

[0022] The protection circuit is disposed between the pixel section 17 and the scanning line input terminal 11 and the signal line input terminal 12. In this embodiment, a plurality of protection circuits are provided to protect the scanning lines 13, the signal lines 14 and the capacitive bus lines. 27 is applied with a surge voltage due to static electricity or the like, and the pixel transistor 19 and the like are not destroyed. Therefore, when a surge voltage is applied to the protection circuit, It is configured to dissipate charge to line 29 or common wiring 28 .

[0023] In this embodiment, a protection circuit 24 is provided on the scanning line 13 side, a protection circuit 25 is provided on the signal line 14 side, and a capacitance bus line 2 7 side. However, the configuration of the protection circuit is not limited to this. do not have.

[0024] FIG. 2 shows an example of a protection circuit. This protection circuit is made up of non-transitory It is composed of a linear element 30 and a nonlinear element 31. The element 31 is composed of a two-terminal element such as a diode or a three-terminal element such as a transistor. For example, the nonlinear element can be formed in the same process as the pixel transistor of the pixel section. For example, a diode can be formed by connecting the gate terminal and drain terminal of a nonlinear element. can have similar characteristics.

[0025] The first terminal (gate) and the third terminal (drain) of the nonlinear element 30 are connected to the scan line 13. The second terminal (source) is connected to the common wiring 29. The first terminal of the nonlinear element 31 The gate and drain terminals are connected to a common wiring 29, and the source terminal is connected to a That is, the protection circuit shown in FIG. The transistors are connected to the scanning line 13 and the common line 2 with their rectification directions opposite to each other. In other words, between the scanning line 13 and the common wiring 29, A transistor that faces the common wiring 29 from the scanning line 13 and a transistor that faces the common wiring 29 from the scanning line The configuration is such that the transistors leading to 13 are connected.

[0026] The protection circuit shown in FIG. 2 is a protection circuit for preventing the scanning line 13 from being charged positively or negatively with respect to the common line 29 due to static electricity or the like. For example, if the scanning line 13 is positively charged, a current flows in the direction that cancels the charge. When the positive charge is released, a current flows in the direction to release the positive charge to the common wiring 29. Electrostatic breakdown or threshold voltage shift of pixel transistor 19 connected to the energized scan line 13 In addition, the electric charge of the scanning line 13 intersecting the insulating layer can be prevented. It is possible to prevent dielectric breakdown of the insulating film between other wirings.

[0027] 2 shows a nonlinear element 30 having a first terminal (gate) connected to the scanning line 13 and a common wiring 2 A nonlinear element 31 having a first terminal (gate) connected to 9, i.e., two elements having opposite rectification directions. A pair of nonlinear elements is used, and the second terminal (source) and the third terminal (drain) of each are connected in common. The line 29 and the scanning line 13 are connected in parallel. A linear element may be added to improve the operational stability of the protection circuit. For example, FIG. and the common wiring 29. The protection circuit shown in FIG. 1 is composed of a common wiring, a nonlinear element, and a nonlinear element. Two nonlinear elements (30b, 31b) whose first terminals (gates) are connected to the line 29, and a scanning line The first terminal (gate) of each of the two nonlinear elements (30a, 31a) is connected to the first terminal (gate) of the nonlinear element 13. A linear element is used. In other words, two nonlinear elements are used so that the rectification directions are opposite to each other. A pair of these is connected between the common wiring 29 and the scanning line 13. Between the scanning line 13 and the common wiring 29, there are two rectifying lines whose rectifying direction is from the scanning line 13 to the common wiring 29. and two transistors whose rectification direction is from the common line 29 to the scanning line 13. In this way, the common wiring 29 and the scanning line 13 are connected by four nonlinear elements. By connecting the common wiring 29 to the scanning line 13, not only when a surge voltage is applied to the common wiring 29, Even if the surface is charged by air or other factors, the charge will flow directly into the scanning line 13. In FIG. 28, four nonlinear elements 740a, 740b, An embodiment in which the elements 40c and 740d are arranged on a substrate is shown together with an equivalent circuit diagram. In FIG. 8, 650 indicates a scanning line and 651 indicates a common line.

[0028] As an example of a protection circuit using an odd number of nonlinear elements, the layout of nonlinear elements on a board is shown below. FIG. 27(A) shows an equivalent circuit, and FIG. 27(B) shows an equivalent circuit. The nonlinear element 730b and the nonlinear element 730a are connected as switching elements. By connecting nonlinear elements in series in this way, the nonlinear elements that make up the protection circuit In FIG. 27, 650 is the scanning line, 651 is the common line, show.

[0029] FIG. 2 shows an example of a protection circuit provided on the side of the scanning line 13, but a protection circuit of a similar configuration can be provided on the side of the signal line 14. It can also be applied to the side.

[0030] FIG. 4A is a plan view showing an example of a protection circuit, and FIG. 4B shows its equivalent circuit diagram. FIG. 5 shows a cross-sectional view corresponding to the line Q1-Q2 shown in FIG. 4(A). Next, an example of the configuration of the protection circuit will be described with reference to FIG. 4 and FIG.

[0031] The nonlinear element 30a and the nonlinear element 30b have gate electrodes formed in the same layer as the scanning line 13. On the gate electrode 15 and the gate electrode 16, a gate An insulating layer 37 is formed. On the gate insulating layer 37, a gate electrode 15 is provided so as to face the gate electrode 15. A first wiring layer 38 and a second wiring layer 39 are provided on the nonlinear element 30a. Linear element 30b has the same main construction.

[0032] The first oxide semiconductor layer 36 covers the area between the first wiring layer 38 and the second wiring layer 39 which face each other. That is, the first oxide semiconductor layer 36 overlaps with the gate electrode 15, The side portions of the conductive layer 41 in the gate insulating layer 37, the first wiring layer 38, and the second wiring layer 39 and the first The first oxide semiconductor layer 40 is provided so as to be in contact with the side and top surfaces of the second oxide semiconductor layer 40. The wiring layer 38 and the second wiring layer 39 are formed by connecting the conductive layer 41 and the second oxide semiconductor layer 42 from the gate insulating layer 37 side. The gate insulating layer 37 is made of silicon oxide or It is formed from oxides such as aluminum.

[0033] The first oxide semiconductor layer 36 has a higher oxygen concentration than the second oxide semiconductor layer 40. In other words, the first oxide semiconductor layer 36 is an oxygen-excess type, and the second oxide semiconductor layer The reference numeral 40 denotes an oxygen-deficient type. By increasing the oxygen concentration in the first oxide semiconductor layer 36, a donor-type deficiency is formed. This has the effect of reducing the number of defects and improving the carrier lifetime and mobility. On the other hand, the second oxide semiconductor layer 40 has an oxygen concentration lower than that of the first oxide semiconductor layer 36. By lowering the thickness of the source and drain regions, the carrier concentration can be increased. It can be used to

[0034] In terms of the structure of the oxide semiconductor, the first oxide semiconductor layer 36 has an amorphous structure, and the second oxide semiconductor layer The conductor layer 40 may contain nanocrystals in its amorphous structure. The oxide semiconductor layer 36 has a characteristic of being lower in electrical conductivity than the second oxide semiconductor layer 40. Therefore, in the nonlinear element 30a and the nonlinear element 30b of the present embodiment, the first wiring layer The second oxide semiconductor layer 40 used as a component of the second wiring layer 38 and the second wiring layer 39 is The MOSFETs function similarly to the source and drain regions of a transistor.

[0035] The first oxide semiconductor layer 36 and the second oxide semiconductor layer 40 are typically made of oxide semiconductors such as The semiconductor layer is made of zinc oxide (ZnO) or an oxide semiconductor material containing In, Ga, and Zn. can be.

[0036] The first oxide semiconductor layer 36 is provided in contact with the gate insulating layer 37. The layer 36 is in contact with a second oxide semiconductor layer 40 having a higher electrical conductivity than the first oxide semiconductor layer 36. The junction structure between oxide semiconductor layers with different physical properties as described above is used as the nonlinear element 3. By providing the first wiring layer 38 and the second wiring layer 39 in the nonlinear element 30a and the nonlinear element 30b, This allows for more stable operation than a Schottky junction formed with only a metal layer. In other words, compared to the case of only metal wiring, the thermal stability is increased, and stable operation is achieved. This makes it possible to improve the functionality of the protection circuit and stabilize operation. In addition, the junction leakage is reduced, improving the characteristics of the nonlinear elements 30a and 30b. It is possible.

[0037] The first wiring layer 38 and the second wiring layer 39 are configured as follows: A second oxide semiconductor layer 40 is provided on the first oxide semiconductor layer, and a top surface of the second oxide semiconductor layer 40 and the first oxide semiconductor layer 41 are By adopting a structure in which the conductor layers 36 are in contact with each other, the area of ​​the junction is increased, and the current of the nonlinear element 30a Therefore, when the nonlinear element 30a is used in a protection circuit, Even if a surge voltage is applied to a signal line, the charged electric charge flows more quickly to the common wiring. It is possible.

[0038] An interlayer insulating layer 42 is provided on the first oxide semiconductor layer 36. The interlayer insulating layer 42 is made of an oxide The insulating layer is formed of an oxide such as silicon oxide or aluminum oxide. Silicon nitride, aluminum nitride, silicon oxynitride or aluminum oxynitride on aluminum nitride By laminating aluminum, the function as a protective film can be improved.

[0039] In any case, by making the interlayer insulating layer 42 in contact with the first oxide semiconductor layer 36 an oxide, In this case, oxygen is prevented from being extracted from the first oxide semiconductor layer 36, and the first oxide semiconductor layer 36 is prevented from changing into an oxygen-deficient type. In addition, the first oxide semiconductor layer 36 does not directly contact the insulating layer made of nitride. By adopting such a structure, hydrogen in the nitride is diffused to form hydroxyl groups in the first oxide semiconductor layer 36. Therefore, it is possible to prevent the generation of defects caused by the above-mentioned problems.

[0040] A contact hole 43 is provided in the interlayer insulating layer 42, and the gate electrode 15 is formed in the same layer. The formed scanning line 13 is connected to the third terminal (drain) of the nonlinear element 30a. The connection is made by a third wiring layer 44 made of the same material as the pixel electrodes of the pixel section. The wiring layer 44 is made of indium tin oxide (ITO), It is made of materials that form transparent electrodes, such as zinc oxide (ZnO) and tin oxide (SnO2). As a result, the third wiring layer 44 has a higher resistance than wiring made of a metal material. By including wiring with such resistance components in the protection circuit, excessive current will flow. This can prevent the nonlinear element 30a from being destroyed.

[0041] Although an example of a protection circuit provided for the scanning line 13 is shown in FIG. 4 and FIG. 5, a similar protection circuit may be used. The line can be applied to a signal line, a capacitive bus line, etc.

[0042] In this manner, according to the present embodiment, a protection circuit is provided using a nonlinear element using an oxide semiconductor. By doing so, it is possible to obtain a display device having a structure suitable for a protection circuit. The nonlinear element using oxide semiconductors can improve the function of the protection circuit and stabilize its operation. Cut.

[0043] (Embodiment 2) This embodiment mode relates to one aspect of a manufacturing process of the protection circuit shown in FIG. This will be described with reference to Figures 6 and 7. Figures 6 and 7 are taken along the line Q1-Q2 in Figure 4(A). 4A-4C show corresponding cross-sectional views.

[0044] In FIG. 6A, a substrate 100 having light transmission properties is made of commercially available barium borosilicate. Glass substrates such as glass, aluminoborosilicate glass, and aluminosilicate glass are used. For example, barium oxide (BaO) can be used in place of boric acid (B2O3). It is preferable to use a glass substrate containing a large amount of oxide semiconductor (O) and having a distortion point of 730° C. or higher. This is because the glass substrate does not warp even when the layer is heat-treated at a high temperature of around 700°C. .

[0045] Next, a conductive layer is formed on the entire surface of the substrate 100, and then a first photolithography process is performed. A resist mask is formed, and unnecessary parts are removed by etching to form wiring and electrodes (gates). At this time, at least a gate wiring including a gate electrode 101, a capacitance wiring, and a terminal are formed. The gate electrode 101 is etched so that the end portion thereof is tapered. The scanning lines 108 are formed in the same layer as the gate electrodes 101 .

[0046] The gate wiring including the gate electrode 101, the capacitance wiring, and the terminals of the terminal portion are made of aluminum (Al). It is preferable to form the capacitor from a low-resistance conductive material such as aluminum (Al) or copper (Cu), but aluminum alone is not heat-resistant. Since it has problems such as poor electrical conductivity and susceptibility to corrosion, it is formed in combination with heat-resistant conductive materials. Heat-resistant conductive materials include titanium (Ti), tantalum (Ta), and tungsten (W ), molybdenum (Mo), chromium (Cr), or Nd (neodymium), or An alloy film containing the above-mentioned elements as components, an alloy film containing a combination of the above-mentioned elements, or The cross-sectional view at this stage is shown in Figure 6(A).

[0047] Next, a gate insulating layer 102 is formed on the entire surface of the gate electrode 101. The film 2 is formed to a thickness of 50 to 250 nm by using a sputtering method or the like.

[0048] For example, a silicon oxide film is used as the gate insulating layer 102 by sputtering, and the thickness is 100 nm. Of course, the gate insulating layer 102 is not limited to such a silicon oxide film. Silicon oxide nitride film, silicon nitride film, aluminum oxide film, tantalum oxide film, etc. It may be formed as a single layer or a laminate structure made of these materials using other insulating films such as SiO2. good.

[0049] Next, a conductive film made of a metal material is formed on the gate insulating layer 102 by sputtering or vacuum deposition. The conductive film is made of an element selected from Al, Cr, Ta, Ti, Mo, and W, or or an alloy film containing the above elements or a combination of the above elements. Here, a Ti film is used as the conductive film, and an aluminum (Al) film is layered on top of the Ti film. The conductive film is a three-layer structure, with a Ti film formed on top of the first. Alternatively, a titanium film may be laminated on the aluminum film. Alternatively, the insulating film may have a single layer structure of an aluminum film containing titanium or a single layer structure of a titanium film.

[0050] Next, a second oxide semiconductor film is formed on the gate insulating layer 102 by a sputtering method. , indium oxide (In2O3), gallium oxide (Ga2O3), and zinc oxide (ZnO A target with a composition ratio of 1:1:1 (=In2O3:Ga2O3:ZnO) was used. The pressure in the deposition chamber was 0.4 Pa, the power was 500 W, the deposition temperature was room temperature, and the gas was argon. A gas flow rate of 40 sccm is introduced to perform sputtering deposition. As a result, a second oxide semiconductor film A semiconductor film containing In, Ga, Zn and oxygen is formed. The composition ratio is 1:1. Although the target with In2O3:Ga2O3:ZnO was intentionally used, Regardless of the reason, the oxide semiconductor film often contains crystal grains with sizes of 1 nm to 10 nm immediately after deposition. The target component ratio, deposition pressure (0.1 Pa to 2.0 Pa), and power ( 250W~3000W: 8 inch diameter), temperature (room temperature~100℃), etc. of reactive sputtering By adjusting the deposition conditions appropriately, the presence or absence of crystal grains, the density of the crystal flow, and the diameter size can be adjusted to within 1 nm. The thickness of the second oxide semiconductor film can be adjusted in the range of 5 nm to 20 nm. nm. Of course, if the film contains crystal grains, the size of the crystal grains contained in the film exceeds the film thickness. In this embodiment, the thickness of the second oxide semiconductor film is 5 nm.

[0051] The gate insulating layer, the conductive film, and the second oxide semiconductor film are introduced into the chamber by a sputtering method. By appropriately switching the gas and the target to be installed, the gate insulating layer, conductive film, When the first oxide semiconductor film and the second oxide semiconductor film are successively formed without exposure to air, the inclusion of impurities is prevented. In addition, when continuous film formation is performed without exposure to the atmosphere, a multi-chamber method is used. It is preferable to use a production apparatus of the formula:

[0052] Next, a second photolithography step is performed to form a resist mask and a second oxide semiconductor is deposited. The conductive film is etched. In this example, a wet etch was performed using ITO07N (Kanto Chemical Co., Ltd.). By etching, unnecessary portions are removed to form second oxide semiconductor layers 111a and 111b. The etching here is not limited to wet etching, but may be dry etching. It's fine.

[0053] Next, etching is performed using the resist mask used in the etching process of the second oxide semiconductor film. The unnecessary portion of the conductive film on the gate insulating layer is removed by etching to form the source electrode layer 105a and the drain electrode layer 105b. The etching method used here is wet etching or Dry etching is used for this purpose. Here, a mixture of SiCl4, Cl2, and BCl3 is used in reaction. The conductive film, which is a laminate of Ti film, Al film and Ti film, is etched by dry etching using reactive gas. The source electrode layer 105a and the drain electrode layer 105b are formed by etching. The cross-sectional view after removing the mask is shown in FIG.

[0054] Next, plasma treatment is performed. Here, oxygen gas and argon gas are introduced into the deposition chamber to form a plasma. The exposed gate insulating layer is then sputtered with oxygen radicals or oxygen. In this way, dust adhering to the surface is removed, and the surface of the gate insulating layer is exposed to oxygen. The surface of the gate insulating layer is modified to an oxygen-excess region by performing oxygen radical treatment. This allows for a heat treatment (200℃~600℃) to be performed in the subsequent process to improve reliability. In this case, it is effective in providing an oxygen source for modifying the interface between the first oxide semiconductor layer and the oxide semiconductor layer. A cross-sectional view at this stage is shown in FIG.

[0055] Depending on the conditions of the plasma treatment, the exposed source electrode layer 105a and the drain electrode layer 105b may be An oxide film (not shown) is formed on the side of the electrode layer 105b. The electrode layer 105a and the drain electrode layer 105b are in direct contact with the channel formation region. This is not a problem. Rather, the formation of this oxide film The electrode layer 105a and the drain electrode layer 105b are connected to the source region made of the second oxide semiconductor layer. The source region is electrically connected to the channel forming region via the drain region. A source region and a drain region made of a second oxide semiconductor layer are formed on the source electrode layer and the drain electrode layer. Since the plasma treatment is performed after the formation of the region, the source electrode layer and the drain electrode layer are exposed. Only the ends where the source electrode layer and the drain electrode are connected are oxidized. The other areas are not oxidized. The electrode layer can be kept at a low resistance. Since the contact area between the drain region and the first semiconductor layer is large, the source region or drain region is A good electrical connection can be achieved with the conductor layer.

[0056] Next, a first oxide semiconductor film is formed without exposing the plasma-treated substrate to the air. The first oxide semiconductor film is formed without exposing the plasma-treated substrate to the atmosphere. This can prevent problems caused by dust or moisture adhering to the interface between the gate insulating layer and the semiconductor film. In this study, an oxide semiconductor target containing In, Ga, and Zn with a diameter of 8 inches (composition ratio and In2O3:Ga2O3:ZnO=1:1:1) was used to form a layer between the substrate and the target. Distance from the sample was 170 mm, pressure was 0.4 Pa, DC power was 0.5 kW, and the sample was placed in an oxygen atmosphere. By using a pulsed direct current (DC) power supply, dust can be reduced and the film thickness distribution can be made uniform. The thickness of the first oxide semiconductor film is set to 5 nm to 200 nm. In this embodiment, the first oxide semiconductor film has a thickness of 100 nm.

[0057] The first oxide semiconductor film is formed under different film formation conditions from the second oxide semiconductor film. The second oxide semiconductor film has a different composition from the first oxide semiconductor film. For example, the second oxide semiconductor film has a higher oxygen concentration than the first oxide semiconductor film. For example, the second oxide semiconductor film is formed under the following conditions: The ratio of the oxygen gas flow rate to the argon gas flow rate is more important in the deposition conditions of the first oxide semiconductor film. Specifically, the second oxide semiconductor film is formed under the conditions of: Gas (argon, helium, etc.) atmosphere (or oxygen gas 10% or less, argon gas The first oxide semiconductor film is formed under an oxygen atmosphere (or an oxygen gas flow). The first oxide semiconductor film is made of a mixed gas having a flow rate of more than argon gas. By increasing the thickness of the oxide semiconductor film, the conductivity of the oxide semiconductor film can be made lower than that of the second oxide semiconductor film. By including a large amount of oxygen in the first oxide semiconductor film, it is possible to reduce the off-state current. This makes it possible to obtain thin-film transistors with a high on / off ratio.

[0058] The first oxide semiconductor film was formed in the same chamber as the previous reverse sputtering. If the film can be formed without exposing it to the atmosphere, it is acceptable to use a chalcedony that has been reverse sputtered before. The film may be formed in a chamber different from that of the member.

[0059] Next, it is preferable to carry out a heat treatment at 200°C to 600°C, typically 300°C to 500°C. Here, the sample is placed in a furnace and heat-treated at 350°C for 1 hour in a nitrogen atmosphere. This heat treatment rearranges the IGZO semiconductor film at the atomic level. The heat treatment (including photo-annealing) here is important because it releases the distortion that inhibits the movement. Note that there is no particular limitation on the timing of performing the heat treatment as long as it is performed after the formation of the first oxide semiconductor film. Alternatively, the step may be performed after forming the pixel electrodes.

[0060] Next, a third photolithography process is performed to form a resist mask and perform etching. The unnecessary portions are removed to form the first oxide semiconductor layer 103. The first oxide semiconductor layer 103 was formed by wet etching using a fluorine-based fluorine-based compound (manufactured by Kanto Chemical Co., Ltd.). Note that the first oxide semiconductor film and the second oxide semiconductor film are dissolved in the same etchant. Therefore, a part of the second oxide semiconductor film is removed by etching in this step. The second oxide semiconductor film (IGZO semiconductor film) covered with the first oxide semiconductor film and the mask is The second oxide semiconductor film that is protected but exposed is etched to form the source region 104a. The drain region 104b is formed. The etching method is not limited to wet etching, and dry etching may be used. The above steps are performed to remove the oxide semiconductor layer 103 from the nonlinear insulating film 101, which serves as a channel formation region. The element 30a is thus fabricated. A cross-sectional view at this stage is shown in FIG.

[0061] Next, a protective insulating film 107 is formed to cover the nonlinear element 30a. Silicon nitride film, silicon oxide film, silicon oxynitride film, and oxide film obtained by a deposition method, etc. For example, an aluminum oxide film, a tantalum oxide film, or the like can be used.

[0062] Next, a fourth photolithography process is performed to form a resist mask, and a protective insulating film 1 07 is etched to form a contact hole 125 reaching the drain electrode layer 105b. Furthermore, the gate insulating layer 102 is etched using the same resist mask to form a gate electrode. It is preferable to form a contact hole 126 that reaches the electrode, since this reduces the number of photomasks. The resist mask is removed, and the cross-sectional view at this stage is shown in FIG.

[0063] Next, the third wiring layer 128 is formed. If a transparent conductive film is used, the third wiring layer and the pixel electrodes can be formed. The transparent conductive film can be made of indium oxide (In2O3) or indium oxide. ITO is a tin oxide alloy (In2O3-SnO2, abbreviated as ITO) that is formed by sputtering or vacuum evaporation. The etching process for such materials is carried out using a hydrochloric acid based solution. However, since ITO etching is particularly prone to leaving residues, it is necessary to improve the etching processability. For this purpose, an indium oxide-zinc oxide alloy (In2O3-ZnO) may be used. The transparent conductive film is etched as shown above to form the third wiring layer 128.

[0064] Next, a fifth photolithography step is performed to form a resist mask and perform etching. Unnecessary portions of the transparent conductive film are then removed to form pixel electrodes in pixel portions (not shown).

[0065] In addition, in this fifth photolithography process, a gate insulator is formed in a capacitor portion (not shown). The insulating layer 102 and the protective insulating film 107 serve as dielectrics, and a storage capacitor is formed between the capacitance wiring and the pixel electrode. Complete.

[0066] In the fifth photolithography process, the terminal portion is covered with a resist mask. The transparent conductive film formed on the terminals is left. The transparent conductive film is used as an electrode or are wiring, connection terminal electrodes that function as input terminals of source wiring, etc.

[0067] In this embodiment, the third wiring layer 128 made of a transparent conductive film is connected to the nonlinear element 30. The drain electrode layer 105b of a is connected to the scanning line 108 via contact holes 125 and 126. and connect.

[0068] The resist mask is then removed. The cross-sectional view at this stage is shown in Figure 7(C).

[0069] In this way, five photolithography steps were performed using five photomasks to produce multiple In this embodiment, the nonlinear element 30a is connected to the nonlinear element 30b. According to this embodiment, a protection circuit for a nonlinear element can be completed. In addition, multiple TFTs can be fabricated in the same way, so a bottom-gate n-channel The pixel section having the TFT and the protection circuit can be fabricated simultaneously. According to the process shown in this embodiment, an active matrix having a protection diode can be manufactured. It is possible to prepare a substrate for a display device of a type.

[0070] (Embodiment 3) In this embodiment, the protection circuit shown in FIG. 4(A) in the first embodiment is The nonlinear elements are formed using different structures. That is, the source and drain regions The present embodiment is an example of a nonlinear element in which a source electrode layer and a drain electrode layer are provided above and below the source electrode layer and the drain electrode layer. A thin film transistor having a different structure and its manufacturing process will be described with reference to FIGS. 8 and 9. He explains.

[0071] Since this embodiment is only partially different from the first embodiment, the same parts as those in FIGS. The same reference numerals are used for the same steps, and the description of the same steps will be omitted below.

[0072] First, as in the second embodiment, a conductive layer is formed on the substrate 100, and then a first photolithography is performed. A roughening process is performed, a resist mask is formed, and unnecessary parts are removed by etching. Forming wiring and electrodes (gate wiring including the gate electrode 101, capacitance wiring, and first terminal) The cross-sectional view at this stage is shown in Figure 8(A).

[0073] Next, in the same manner as in the second embodiment, a gate insulating layer 102 is formed on the entire surface of the gate electrode 101. The gate insulating layer 102 is formed by sputtering or the like, and has a thickness of 50 to 250 nm. For example, a silicon oxide film is used as the gate insulating layer 102 by sputtering, and a thickness of 110 nm is Form the thickness.

[0074] Next, a third oxide semiconductor film is formed on the gate insulating layer 102 by a sputtering method. Indium oxide (In2O3), gallium oxide (Ga2O3), and zinc oxide (ZnO) A target with a composition ratio of 1:1:1 (=In2O3:Ga2O3:ZnO) was used. The deposition conditions were: pressure 0.4 Pa, power 500 W, deposition temperature room temperature, and Ar. Sputtering is performed with a gas flow rate of 40 sccm. The composition ratio is 1:1:1 (=In2 Although a target of O3:Ga2O3:ZnO was intentionally used, the deposition Immediately after the process, an IGZO semiconductor film containing crystal grains with sizes of 1 nm to 10 nm may be formed. The target component ratio, deposition pressure (0.1 Pa to 2.0 Pa), and power (250 W to 3000W: 8 inch φ), temperature (room temperature to 100℃), reactive sputtering deposition conditions, etc. By adjusting appropriately, the presence or absence of crystal grains, the density of crystal grains, and the diameter size can be adjusted to 1nm to 10nm. The thickness of the third oxide semiconductor film is set to 5 nm to 20 nm. Of course, if the film contains crystal grains, the size of the crystal grains will exceed the film thickness. In this embodiment, the thickness of the IGZO semiconductor film as the third oxide semiconductor film is 5 Let nm.

[0075] Next, a conductive film made of a metal material is formed on the third oxide semiconductor film by sputtering or vacuum deposition. The conductive film is made of an element selected from Al, Cr, Ta, Ti, Mo, and W, or or an alloy film containing the above elements or a combination of the above elements. Here, the conductive film has a single layer structure of an aluminum film containing silicon. The conductive film may have a laminated structure, and a titanium film may be laminated on an aluminum film. A Ti film is used as a conductive film, and an aluminum (Al) film is laminated on top of the Ti film. A three-layer structure may be formed by forming a Ti film on top of that.

[0076] Next, a second oxide semiconductor film is formed on the conductive film by a sputtering method. The second oxide semiconductor film can be formed under the same film formation conditions as those for the third oxide semiconductor film. The second oxide semiconductor film, which was formed under the same conditions as the first oxide semiconductor film, had a size of 1 nm to 10 nm immediately after formation. The thickness of the second oxide semiconductor film is In this embodiment, the thickness of the second oxide semiconductor film is set to 5 nm. do.

[0077] The gate insulating layer, the third oxide semiconductor film, the conductive film, and the second oxide semiconductor film are formed by a sputtering method. By appropriately switching the gas introduced into the chamber and the target installed, The gate insulating layer, the third oxide semiconductor film, the conductive film, and the second oxide semiconductor film are not exposed to the air. Continuous film formation without exposure to air prevents impurities from being mixed in. When continuous film formation is performed without exposure to the atmosphere, the multi-chamber method It is preferable to use a manufacturing apparatus of the above type.

[0078] Next, a second photolithography process is performed, and a resist mask is formed on the second oxide semiconductor film. and then etching is performed to form a third oxide semiconductor film, a conductive film, and a second oxide semiconductor film. The necessary portions are removed to form the first source region 106a, the first drain region 106b, and the source The electrode layer 105a, the drain electrode layer 105b, and the second oxide semiconductor layers 111a and 111b are The etching method used in this process may be wet etching or dry etching. Here, the film is made by wet etching using ITO07N (manufactured by Kanto Chemical Co., Ltd.). After forming the second oxide semiconductor layers 111a and 111b, SiCl4, Cl2, and BCl3 The aluminum film containing silicon was dry-etched using a mixture of these gases as the reactive gas. The conductive film is etched to form the source electrode layer 105a and the drain electrode layer 105b. After that, using the same resist mask, a wafer using ITO07N (Kanto Chemical Co., Ltd.) was A first source region 106a and a first drain region 106b are formed by hot etching. A cross-sectional view after removing the resist mask is shown in FIG.

[0079] Although not shown, in the capacitance section, the IGZO semiconductor film overlapping the capacitance wiring is removed. In addition, the third oxide semiconductor layer remains in the terminal portion.

[0080] Next, plasma treatment is performed. Here, oxygen gas and argon gas are introduced into the deposition chamber to form a plasma. The exposed gate insulating layer is then sputtered with oxygen radicals or oxygen. In this way, dust adhering to the surface is removed, and the surface of the gate insulating layer is exposed to oxygen. The surface of the gate insulating layer is modified to an oxygen-excess region by performing plasma treatment. The next step is to heat treat the chip (200℃~600℃) to improve the reliability of the chip. This is effective in providing an oxygen source for modifying the interface of the first oxide semiconductor layer. The cross-sectional view at the floor level is shown in Figure 8(C).

[0081] In addition, a first source region 106 is formed under the source electrode layer 105a and the drain electrode layer 105b. a and the first drain region 106b are provided, so that the first source region 106a and The plasma damage to the first drain region 106b is reduced. The second oxide semiconductor layers 111a and 111b are formed on the electrode layer 105a and the drain electrode layer 105b. Since the source electrode layer 105a and the drain electrode layer 105b are provided, the Therefore, an increase in the wiring resistance can be suppressed.

[0082] Depending on the conditions of the plasma treatment, the exposed source electrode layer 105a and the drain electrode layer 105b may be An oxide film (not shown) is formed on the side of the electrode layer 105b. The electrode layer 105a and the drain electrode layer 105b are not in direct contact with the channel formation region. On the contrary, the presence of this oxide film causes the source electrode layer 105a and The drain electrode layer 105b is electrically connected to the channel forming region via the source region or the drain region. The structure is electrically connected.

[0083] Next, a first oxide semiconductor film is formed without exposing the plasma-treated substrate to the air. The first oxide semiconductor film is formed without exposing the plasma-treated substrate to the atmosphere. This can prevent problems caused by dust or moisture adhering to the interface between the gate insulating layer and the semiconductor film. In this study, an oxide semiconductor target containing In, Ga, and Zn with a diameter of 8 inches (composition ratio and In2O3:Ga2O3:ZnO=1:1:1) was used to form a layer between the substrate and the target. Distance from the sample was 170 mm, pressure was 0.4 Pa, DC power was 0.5 kW, and the sample was placed in an oxygen atmosphere. By using a pulsed direct current (DC) power supply, dust can be reduced and the film thickness distribution can be made uniform. The thickness of the first oxide semiconductor film is set to 5 nm to 200 nm. In this embodiment, the first oxide semiconductor film has a thickness of 100 nm.

[0084] The first oxide semiconductor film is formed under different film formation conditions from the second and third oxide semiconductor films. The second and third oxide semiconductor films have different compositions. For example, the second and third oxide semiconductor films The first oxide semiconductor film contains more oxygen than the second oxide semiconductor film. The ratio of oxygen gas in the deposition atmosphere for the third oxide semiconductor film is higher than that in the deposition atmosphere for the first oxide semiconductor film. The film atmosphere has a high ratio of oxygen gas.

[0085] Specifically, the second and third oxide semiconductor films are formed under the conditions of a rare gas (argon or helium) (or oxygen gas 10% or less, argon gas 90% or more) atmosphere, and The deposition conditions for the compound semiconductor film are oxygen atmosphere (or oxygen gas flow rate is equal to or higher than argon gas flow rate). and the ratio is 1:1 or more.

[0086] By including a large amount of oxygen in the IGZO semiconductor film as the first oxide semiconductor film, The conductivity can be made lower than that of the IGZO semiconductor film as the second and third oxide semiconductor films. In addition, by incorporating a large amount of oxygen into the IGZO semiconductor film as the first oxide semiconductor film, As a result, a thin-film transistor with a high on-off ratio can be fabricated. You can get a transistor.

[0087] The first oxide semiconductor film was formed in the same chamber as the previous reverse sputtering. If the film can be formed without exposing it to the atmosphere, it is acceptable to use a chalcedony that has been reverse sputtered before. The film may be formed in a chamber different from that of the member.

[0088] Next, it is preferable to carry out a heat treatment at 200°C to 600°C, typically 300°C to 500°C. Here, the sample is placed in a furnace and heat-treated at 350°C for 1 hour in a nitrogen atmosphere. This heat treatment rearranges the IGZO semiconductor film at the atomic level. The heat treatment (including photo-annealing) here is important because it releases the distortion that inhibits the movement. Note that there is no particular limitation on the timing of performing the heat treatment as long as it is performed after the formation of the first oxide semiconductor film. Alternatively, the step may be performed after forming the pixel electrodes.

[0089] Next, a third photolithography process is performed to form a resist mask and perform etching. The unnecessary portions are removed to form the first oxide semiconductor layer 103. (manufactured by Kanto Chemical Co., Ltd.) to remove unnecessary portions of the first oxide semiconductor film. The first oxide semiconductor layer 103 is formed by removing the first oxide semiconductor film and the second oxide semiconductor film. The oxide semiconductor film and the third oxide semiconductor film are dissolved in the same etchant. By etching, part of the second oxide semiconductor film and part of the third oxide semiconductor film are removed. The remaining second oxide semiconductor film, which is covered with the resist mask and the first oxide semiconductor film, is The third oxide semiconductor film is a first source region 104a and a second drain region 104b. The side surface covered with the first oxide semiconductor film is protected, but as shown in FIG. The other side of the nitride semiconductor film is exposed and is slightly etched to define the shape of the end face. The etching of the first oxide semiconductor layer 103 is not limited to wet etching. Through the above steps, the first oxide semiconductor layer 103 is The cross-sectional view at this stage is shown in FIG. show.

[0090] Next, a protective insulating film 107 is formed to cover the nonlinear element 30a. Since this is the same as state 2, only a brief explanation will be given here.

[0091] After forming the protective insulating film 107, a fourth photolithography process is performed to form a resist mask. Then, the protective insulating film 107 is etched to form contact holes 125 and 126. A cross-sectional view after removing the resist mask is shown in FIG.

[0092] Next, after forming a transparent conductive film, a fifth photolithography process is performed to form a resist pattern. The unnecessary portion of the transparent conductive film is removed by etching to form a mask (not shown). A pixel electrode is formed.

[0093] In this embodiment, the third wiring layer 128 made of a transparent conductive film is connected to the nonlinear element 30. The drain electrode layer 105b of a is connected to the scanning line 108 via contact holes 125 and 126. The cross section at this stage is shown in Figure 9(C).

[0094] In this way, five photolithography steps were performed using five photomasks to produce multiple In this embodiment, the nonlinear element 30a is connected to the nonlinear element 30b. According to this embodiment, a protection circuit for a nonlinear element can be completed. In addition, multiple TFTs can be fabricated in the same way, so a bottom-gate n-channel The pixel section having the TFT and the protection circuit can be fabricated simultaneously. In other words, by following the process shown in this embodiment, the occurrence of defects in the protection circuit due to peeling of the thin film can be reduced. It is now possible to manufacture a substrate for an active matrix display device equipped with a protective diode. can.

[0095] In addition, the source region 106a and the drain region 106b are formed of the gate insulating layer 102 and the third oxide semiconductor layer. The adhesion of the gate insulating film 106b is good, and the thin film is unlikely to peel off. Compared with the case where a metal wiring such as aluminum is directly formed in contact with the layer 102, the source electrode Since the adhesion between the drain electrode layer 105a and the drain electrode layer 105b is improved, the peeling of the thin film is prevented. This can prevent malfunction of the protection circuit.

[0096] (Embodiment 4) In this embodiment, as a display device to which one embodiment of the present invention is applied, a protection circuit and a pixel portion are disposed. 2 shows an example of electronic paper having TFTs on the same substrate.

[0097] FIG. 10 shows an active matrix type electronic display device as an example of a display device to which one embodiment of the present invention is applied. The thin film transistor 581 used in the display device is the same as that in the embodiment 2. The thin film transistor 581 can be fabricated in the same manner as the nonlinear element shown in FIG. A gate insulating layer, a source region and a drain region made of an oxygen-deficient IGZO semiconductor film, A source electrode layer and a drain electrode layer in contact with the source region and the drain region, A thin-film transistor with high electrical properties having an oxygen-rich IGZO semiconductor layer in contact with the drain region It's Jista.

[0098] The electronic paper in Figure 10 is an example of a display device that uses the twisting ball display method. The spherical display method is an electrode layer that uses spherical particles painted in black and white as display elements. A potential difference is applied between the first electrode layer and the second electrode layer. This is a method of displaying information by controlling the orientation of spherical particles caused by the generation of light.

[0099] The thin film transistor 581 is a thin film transistor having a bottom gate structure, and the source electrode layer The drain electrode layer is in contact with the first electrode layer 587 through an opening formed in the insulating layer 585. A black area 590 is provided between the first electrode layer 587 and the second electrode layer 588. a and white region 590b, and a liquid provided around black region 590a and white region 590b. A spherical particle 589 is provided having a filled cavity 594, the spherical particle The periphery of 589 is filled with a filler 595 such as resin (see FIG. 10). In this figure, 580 is a substrate, 583 is an interlayer insulating layer, 584 is a protective film, and 596 is a substrate.

[0100] Also, instead of the twist ball, an electrophoretic element can be used. and a 10μm to 20μm diameter nanoparticle that contains positively charged white nanoparticles and negatively charged black nanoparticles. Microcapsules with a diameter of about 0 μm are used. When an electric field is applied to the microcapsules by the first and second electrode layers, the microcapsules emit white light. White particles and black particles move in opposite directions, allowing the display to be white or black. A display element that applies this principle is an electrophoretic display element, commonly known as electronic paper. Electrophoretic display elements have a higher reflectivity than liquid crystal display elements, so auxiliary lights are not required. It also consumes little power and the display can be seen even in dimly lit places. Even if power is not supplied to the display, the image that was displayed can be retained. Therefore, for example, a semiconductor device with a display function (simply a display) can be connected to a radio wave source that serves as a power supply source. Even if the display device (also called a display device or a semiconductor device equipped with a display device) is placed away from the It is then possible to store the image.

[0101] According to this embodiment, a protection circuit is configured with a nonlinear element using an oxide semiconductor. As a result, it is possible to obtain a display device having a structure suitable for a protection circuit. In a connection structure between an oxide semiconductor layer and a wiring layer, the second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a region that is in contact with the second oxide semiconductor layer, compared to the case where only metal wiring is provided, This allows for stable operation, improving the functionality of the protection circuit and stabilizing operation. In this way, according to the present embodiment, a highly reliable electronic device can be used as a display device. In addition, by using the same structure as in embodiment 3, Reliable protection circuitry made of nonlinear elements that are less susceptible to defects caused by peeling of thin films It is possible to manufacture a display device with high optical performance.

[0102] This embodiment can be implemented in appropriate combination with the configuration described in the first embodiment. be.

[0103] (Embodiment 5) In this embodiment, in a display device which is an example of a semiconductor device of one embodiment of the present invention, At least a protection circuit, a part of a driving circuit, and a thin film transistor to be arranged in a pixel portion are arranged on the board. An example of the preparation will be described below.

[0104] The thin film transistor disposed in the pixel portion has a shape similar to that of the nonlinear element shown in the second or third embodiment. In addition, since the thin film transistor formed is an n-channel TFT, the driving circuit Of these, a part of the driver circuit that can be configured with n-channel TFTs is a thin-film transistor in the pixel area. It is formed on the same substrate as the resistor.

[0105] A block diagram of an active matrix liquid crystal display device which is an example of a semiconductor device of one embodiment of the present invention. An example of the circuit diagram is shown in FIG. 11A. The display device shown in FIG. A pixel portion 5301 having a plurality of pixels each having a display element, and a scanning line driver circuit 5302 for selecting each pixel. 302 and a signal line driver circuit 5303 for controlling the input of a video signal to a selected pixel. Yes.

[0106] The pixel portion 5301 includes a signal line driver circuit 5303 and a plurality of signal lines arranged in a column direction. The signal line driver circuit 5303 is connected to the signal line driver circuit 5303 by lines S1 to Sm (not shown). A plurality of scanning lines G1 to Gn (not shown) are arranged extending from 5302 in the row direction. The scanning line driver circuit 5302 is connected to the signal lines S1 to Sm and the scanning lines G1 to Gn. The image sensor has a plurality of pixels (not shown) arranged in a matrix. Signal line Sj (any one of signal lines S1 to Sm), scanning line Gi (any one of scanning lines G1 to Gn) Either one of them is connected.

[0107] Also, a thin film transistor can be formed in the same manner as the nonlinear element shown in the second or third embodiment. is an n-channel TFT, and the signal line driver circuit is composed of n-channel TFTs. This will be explained using FIG.

[0108] The signal line driver circuit shown in FIG. 02_M, a first wiring 5611, a second wiring 5612, a third wiring 5613 and a wiring 56 Each of the switch groups 5602_1 to 5602_M includes A first thin film transistor 5603a, a second thin film transistor 5603b, and a third thin film transistor It has a transistor 5603c.

[0109] The driver IC 5601 is connected to a first wiring 5611, a second wiring 5612, and a third wiring 5613. and are connected to the wirings 5621_1 to 5621_M. 5602_M are a first wiring 5611, a second wiring 5612, a third wiring 561 3 and wiring 5621_1 to 5621_5 corresponding to the switch groups 5602_1 to 5602_M, respectively. Each of the wirings 5621_1 to 5621_M is connected to the first A thin film transistor 5603a, a second thin film transistor 5603b, and a third thin film transistor For example, the wiring 5621 in the Jth column is connected to three signal lines via a resistor 5603c. _J (any one of the wirings 5621_1 to 5621_M) is a switch group 5602 The first thin film transistor 5603a, the second thin film transistor 5603b, and and the third thin film transistor 5603c, the signal line Sj-1, the signal line Sj, the signal line S j+1 is connected to

[0110] The first wiring 5611, the second wiring 5612, and the third wiring 5613 are each connected to a signal line. The number is entered.

[0111] It is preferable that the driver IC 5601 is formed on a single crystal substrate. The switch group 5602_1 to 5602_M is formed on the same substrate as the pixel section. Therefore, the driver IC 5601 and the switch group 5602_1 to 5602_ It is recommended to connect to M via an FPC or similar.

[0112] Next, the operation of the signal line driver circuit shown in FIG. 12 will be described with reference to the timing chart of FIG. The timing chart of FIG. 13 is explained with reference to the timing chart when the i-th scanning line Gi is selected. Further, during the selection period of the i-th scanning line Gi, is divided into a first sub-selection period T1, a second sub-selection period T2, and a third sub-selection period T3. Furthermore, when a scanning line of another row is selected, the signal line driver circuit of FIG. In this case, the same operation as in FIG. 13 is performed.

[0113] In the timing chart of FIG. 13, the wiring 5621_J in the Jth column is connected to the first thin-film transistor. a second thin film transistor 5603b, and a third thin film transistor 560 When connected to signal line Sj-1, signal line Sj, and signal line Sj+1 via 3c It shows.

[0114] In the timing chart of FIG. 13, the timing when the i-th scanning line Gi is selected, The on / off timing 5703a of the first thin film transistor 5603a, The on / off timing 5703b of the third thin film transistor 56 The on / off timing of 03c is input to 5703c and the wiring 5621_J of the Jth row. 5 shows signal 5721_J.

[0115] The wirings 5621_1 to 5621_M are connected to the first sub-selection period T1 and the second sub-selection period T2. In the first sub-selection period T2 and the third sub-selection period T3, different video signals are input. For example, the video signal input to the wiring 5621_J in the first sub-selection period T1 is The signal is input to the signal line Sj-1 and is input to the wiring 5621_J in the second sub-selection period T2. The video signal to be output is input to the signal line Sj, and the line 5621 is connected to the line Sj during the third sub-selection period T3. The video signal input to the first sub-selection period is input to the signal line Sj+1. In the period T1, the second sub-selection period T2, and the third sub-selection period T3, the wiring 5621_ The video signals input to J are Data_j-1, Data_j, and Data_j+ Let's say it's 1.

[0116] As shown in FIG. 13, in the first sub-selection period T1, the first thin film transistor 5603 a is turned on, and the second thin film transistor 5603b and the third thin film transistor 5603c At this time, Data_j-1 input to the wiring 5621_J is turned off. The signal is input to the signal line Sj-1 via the transistor 5603a. Second sub-selection period T2 In this case, the second thin film transistor 5603b is turned on, and the first thin film transistor 5603a is turned on. and the third thin film transistor 5603c are turned off. At this time, the input The Data_j to be output is input to the signal line Sj via the second thin film transistor 5603b. In the third sub-selection period T3, the third thin film transistor 5603c is turned on, and the first The first thin film transistor 5603a and the second thin film transistor 5603b are turned off. At this time, Data_j+1 input to the wiring 5621_J is input to the third thin film transistor 56 03c and input to the signal line Sj+1.

[0117] From the above, the signal line driver circuit in FIG. 12 divides one gate selection period into three. During one gate selection period, a video signal is input from one wiring 5621 to three signal lines. Therefore, the signal line driver circuit of FIG. The number of connections between the substrate on which the pixel area is formed and the substrate on which the pixel area is formed is reduced to about one-third of the number of signal lines. By reducing the number of connections to about one third, the signal line driver circuit of FIG. This can improve productivity and yield.

[0118] As shown in FIG. 12, one gate selection period is divided into multiple sub-selection periods, and multiple sub-selection periods are During each selection period, a video signal is input from one line to each of multiple signal lines. As long as this can be achieved, the arrangement, number, driving method, etc. of the thin film transistors are not limited.

[0119] For example, three or more signal lines are connected to one wiring during each of three or more sub-selection periods. When a video signal is input to each of them, a thin film transistor and a thin film transistor are controlled. However, it is necessary to divide one gate selection period into four or more sub-selection periods. Therefore, one gate selection period is divided into two or It is preferably divided into three sub-selection periods.

[0120] As another example, as shown in the timing chart of FIG. 14, one selection period is precharged. The first sub-selection period Tp, the first sub-selection period T1, the second sub-selection period T2, and the third sub-selection period T 3. Furthermore, in the timing chart of FIG. 14, the scanning line Gi of the i-th row is selected. the timing at which the first thin film transistor 5603a is turned on and off; 03a, the on / off timing 5803b of the second thin film transistor 5603b, The on / off timing 5803c of the thin film transistor 5603c and the wiring 5 14, the signal 5821_J input to the pre-channel 621_J is shown. During the transition period Tp, the first thin film transistor 5603a and the second thin film transistor 56 At this time, the wiring 5621_J and the third thin film transistor 5603b are turned on. The precharge voltage Vp input to the first thin film transistor 5603a and the second thin film transistor and the third thin film transistor 5603c are connected to the signal line S j-1, signal line Sj, and signal line Sj+1. The first thin film transistor 5603a is turned on, and the second thin film transistor 5603b and the third thin film transistor At this time, the thin film transistor 5603c is turned off. ata_j-1 is input to the signal line Sj-1 via the first thin film transistor 5603a. In the second sub-selection period T2, the second thin film transistor 5603b is turned on, and the first The first thin film transistor 5603a and the third thin film transistor 5603c are turned off. At this time, Data_j input to the wiring 5621_J is input to the second thin film transistor 5603 In the third sub-selection period T3, the third thin-film transistor The first thin film transistor 5603a and the second thin film transistor 5603c are turned on. At this time, Data_j+1 input to the wiring 5621_J is , and is input to the signal line Sj+1 via the third thin film transistor 5603c.

[0121] From the above, the signal line driver circuit of FIG. 12 to which the timing chart of FIG. 14 is applied By providing a precharge period before the selection period, the signal line can be precharged. Therefore, the video signal can be written to the pixel at high speed. 13 are shown with the same reference numerals, and the same parts or parts having similar functions are shown. A detailed description of the relevant parts will be omitted.

[0122] The configuration of the scanning line driver circuit will be described. The scanning line driver circuit includes a shift register, a buffer, and a In some cases, a level shifter may be included. In the circuit, a clock signal (CLK) and a start pulse signal (SP ) is input, the selection signal is generated. The generated selection signal is buffered The signal is buffered and amplified in the 10-bit signal line and then fed to the corresponding scan line. The gate electrodes of the transistors are connected. Since they must all be turned on at the same time, the buffer must be capable of passing a large current. Used.

[0123] One form of a shift register used as a part of a scanning line driving circuit is shown in FIG. 15 and FIG. 16. He explains.

[0124] The circuit configuration of the shift register is shown in Figure 15. The shift register shown in Figure 15 has multiple free The first flip-flop is composed of flip-flops 5701_1 to 5701_n. The first clock signal, the second clock signal, the start pulse signal, and the reset signal are input. It works like this.

[0125] The connection relationship of the shift register in Fig. 15 will be described. The shift register in Fig. 15 has i-stage The first flip-flop 5701_i (flip-flops 5701_1 to 5701_n In either one of them, the first wiring 5501 shown in FIG. 16 is connected to the seventh wiring 5717_i-1. 16 is connected to the seventh wiring 5717_i+1. 16 is connected to the seventh wiring 5717_i, The sixth wiring 5506 is connected to the fifth wiring 5715 .

[0126] In addition, the fourth wiring 5504 shown in FIG. 16 corresponds to the second wiring in the odd-numbered flip-flops. 5712, and in the even-numbered flip-flops, it is connected to the third wiring 5713. The fifth wiring 5505 shown in FIG.

[0127] However, the first wiring 5501 shown in FIG. 16 of the first-stage flip-flop 5701_1 is 16 of the n-th flip-flop 5701_n. The second wiring 5502 is connected to the sixth wiring 5716 .

[0128] The first wiring 5711, the second wiring 5712, the third wiring 5713, and the sixth wiring 57 16 can be called the first signal line, the second signal line, the third signal line, and the fourth signal line, respectively. Furthermore, the fourth wiring 5714 and the fifth wiring 5715 are respectively connected to the first power supply line and the third power supply line. This may also be called the power line 2.

[0129] Next, the details of the flip-flop shown in FIG. 15 are shown in FIG. The flip-flop includes a first thin film transistor 5571, a second thin film transistor 5572, A third thin film transistor 5573, a fourth thin film transistor 5574, a fifth thin film transistor a sixth thin film transistor 5575, a seventh thin film transistor 5576, and and an eighth thin film transistor 5578. A second thin film transistor 5572, a third thin film transistor 5573, a fourth thin film transistor a fifth thin film transistor 5574, a fifth thin film transistor 5575, a sixth thin film transistor 5576, The seventh thin film transistor 5577 and the eighth thin film transistor 5578 are n-channel A transistor in which the gate-source voltage (Vgs) exceeds the threshold voltage (Vth). When this occurs, the device is in a conductive state.

[0130] Next, the connection configuration of the flip-flop shown in FIG. 16 will be described below.

[0131] A first electrode (either a source electrode or a drain electrode) of the first thin film transistor 5571 is connected to a fourth wiring 5504, and a second electrode (source) of the first thin film transistor 5571 is connected to The other of the source electrode and the drain electrode is connected to a third wiring 5503 .

[0132] A first electrode of the second thin film transistor 5572 is connected to the sixth wiring 5506. A second electrode of the thin film transistor 5572 is connected to a third wiring 5503 .

[0133] A first electrode of the third thin film transistor 5573 is connected to a fifth wiring 5505. The second electrode of the thin film transistor 5573 is the gate electrode of the second thin film transistor 5572. , and the gate electrode of the third thin film transistor 5573 is connected to the fifth wiring 5505. will be done.

[0134] A first electrode of the fourth thin film transistor 5574 is connected to a sixth wiring 5506. The second electrode of the thin film transistor 5574 is the gate electrode of the second thin film transistor 5572. , and the gate electrode of the fourth thin film transistor 5574 is connected to the first thin film transistor 5 It is connected to the gate electrode of 571.

[0135] A first electrode of the fifth thin film transistor 5575 is connected to a fifth wiring 5505. The second electrode of the thin film transistor 5575 is the gate electrode of the first thin film transistor 5571. , and the gate electrode of the fifth thin film transistor 5575 is connected to the first wiring 5501. will be done.

[0136] A first electrode of the sixth thin film transistor 5576 is connected to the sixth wiring 5506. The second electrode of the thin film transistor 5576 is the gate electrode of the first thin film transistor 5571. , and the gate electrode of the sixth thin film transistor 5576 is connected to the second thin film transistor 5 It is connected to the gate electrode of 572.

[0137] A first electrode of the seventh thin film transistor 5577 is connected to the sixth wiring 5506. The second electrode of the thin film transistor 5577 is the gate electrode of the first thin film transistor 5571. , and the gate electrode of the seventh thin film transistor 5577 is connected to the second wiring 5502. A first electrode of the eighth thin film transistor 5578 is connected to the sixth wiring 5506. The second electrode of the eighth thin film transistor 5578 is connected to the gate of the second thin film transistor 5572. The gate electrode of the eighth thin film transistor 5578 is connected to the first wiring 550. Connected to 1.

[0138] The gate electrode of the first thin film transistor 5571 and the gate electrode of the fourth thin film transistor 5574 the gate electrode of the fifth thin film transistor 5575, the second electrode of the sixth thin film transistor The connection point of the second electrode of the seventh thin film transistor 5576 and the second electrode of the seventh thin film transistor 5577 is Further, the gate electrode of the second thin film transistor 5572, the gate electrode of the third thin film transistor 5543, a second electrode of the fourth thin film transistor 5573; a second electrode of the fourth thin film transistor 5574; The gate electrode of the sixth thin film transistor 5576 and the gate electrode of the eighth thin film transistor 5578 The connection point of the two electrodes is designated as node 5544.

[0139] The first wiring 5501, the second wiring 5502, the third wiring 5503 and the fourth wiring 5504 are 504 may be called the first signal line, the second signal line, the third signal line, and the fourth signal line, respectively. Furthermore, the fifth wiring 5505 is a first power supply line, and the sixth wiring 5506 is a second power supply line. It may also be called.

[0140] In addition, the signal line driver circuit and the scanning line driver circuit may be formed in combination with the nonlinear element shown in the second or third embodiment. It is also possible to fabricate the device using only n-channel TFTs, which can be formed in a similar manner. An n-channel TF that can be formed in the same manner as the nonlinear element shown in the second or third embodiment. Since T has a high transistor mobility, it is possible to increase the driving frequency of the driving circuit. In addition, the n-channel MOSFET can be formed in the same manner as the nonlinear element shown in the second or third embodiment. The panel-type TFT is made of a silicon-based oxide semiconductor layer that contains indium, gallium, and zinc. The parasitic capacitance is reduced by the source or drain region, so the frequency characteristics (called f characteristics) For example, the nonlinear element shown in the second or third embodiment can be formed in the same manner. The scanning line driver circuit using n-channel TFTs can operate at high speed. It is also possible to increase the frame frequency or insert a black screen. It is possible to do this.

[0141] Furthermore, the channel width of the transistor of the scanning line driving circuit is increased, and multiple scanning lines By arranging the drive circuit, it is possible to achieve even higher frame frequencies. When multiple scanning line driving circuits are arranged, a scanning line driving circuit for driving the even-numbered scanning lines is provided. The circuit is placed on one side, and the scanning line driving circuit for driving the odd-numbered scanning lines is placed on the opposite side. By placing the pixel clock in the pixel clockwise direction, it is possible to realize a high frame frequency.

[0142] In addition, an active matrix light-emitting display device, which is an example of a semiconductor device to which one embodiment of the present invention is applied, In manufacturing a display device, a plurality of thin film transistors are arranged in at least one pixel. It is preferable that a plurality of scanning line driving circuits are arranged. An example of a block diagram is shown in FIG.

[0143] The light-emitting display device shown in FIG. 11B has a plurality of pixels each having a display element over a substrate 5400. A pixel portion 5401 for selecting each pixel, a first scanning line driver circuit 5402 for selecting each pixel, and a second scanning line driver circuit 5403 for selecting each pixel. A driver circuit 5404 and a signal line driver circuit 5405 for controlling the input of a video signal to a selected pixel 403.

[0144] In the case where a video signal input to a pixel of the light-emitting display device shown in FIG. 11(B) is in a digital format, When a pixel is turned on, the transistor is switched on and off to make it either emitting light or not. Therefore, gray scale display can be performed using area gray scale or time gray scale. The stacked gray scale method divides one pixel into multiple sub-pixels, and each sub-pixel is independently driven based on a video signal. The time gray scale method is a driving method that displays gray scales by changing the time when the pixel emits light. This is a driving method that displays gradations by controlling the period during which the liquid crystal display is turned on.

[0145] Light-emitting elements have a higher response speed than liquid crystal elements, so they are more suitable for time gray scale modulation than liquid crystal elements. Specifically, when displaying using the time gray scale method, one frame period is divided into multiple subframes. Then, the light emitting element of the pixel is divided into sub-frame periods according to the video signal. By dividing the period into multiple subframes, The total length of time that pixels actually emit light during one frame is controlled by the video signal. It is possible to control the brightness and display gradation.

[0146] In the light-emitting display device shown in FIG. 11B, a switching TFT and a When two TFTs are arranged, the first TFT, which is the gate wiring of the switching TFT, The signal input to the scanning line is generated by the first scanning line driver circuit 5402, and the current control TFT A signal input to the second scanning line, which is a gate wiring, is generated by a second scanning line driver circuit 5404. In this example, the signal input to the first scanning line and the signal input to the second scanning line are The signals for the scanning lines may be generated by a single scanning line driving circuit. The operation of the switching element is controlled by the number of transistors that the switching element has. A plurality of first scan lines may be provided for each pixel. All the signals input to the multiple first scanning lines may be generated by one scanning line driver circuit. , may be generated by a plurality of scanning line driving circuits.

[0147] In addition, in the light-emitting display device, the driver circuit may be configured with n-channel TFTs. A part of the driver circuit can be formed on the same substrate as the thin film transistor of the pixel portion. In addition, the signal line driver circuit and the scanning line driver circuit may be used together with the nonlinear element shown in the second or third embodiment. It is also possible to fabricate only n-channel TFTs, which can be formed in a similar manner.

[0148] The above-mentioned driving circuit is not limited to liquid crystal display devices and light-emitting display devices, but may also be used in devices with switching elements and It may also be used in electronic paper, where electrically connected elements are used to drive electronic ink. Electronic paper is also called an electrophoretic display (electrophoretic display) and has the same properties as paper. The advantages are ease of reading, lower power consumption compared to other display devices, and the possibility of making them thin and lightweight. It has points.

[0149] Electrophoretic displays can take a variety of forms, but the first particle has a positive charge. A microcapsule containing a negatively charged second particle and a negatively charged second particle is immersed in a solvent or solute. By applying an electric field to the microcapsules, The particles in the capsule are moved in opposite directions to each other, and only the color of the particles that have gathered on one side is displayed. In addition, the first particles or the second particles contain a dye, and in the absence of an electric field, The first particles and the second particles are different in color (colorless). (including

[0150] Thus, electrophoretic displays operate in such a way that materials with high dielectric constants migrate to areas of high electric field. This is a display that utilizes the so-called dielectrophoretic effect. The display device does not require a polarizing plate or an opposing substrate, which reduces the thickness and weight by half.

[0151] The microcapsules dispersed in a solvent are called electronic ink. The electronic ink can be printed on surfaces such as glass, plastic, fabric, and paper. A color display is also possible by using a color filter or particles having a pigment.

[0152] In addition, the above microphone is appropriately placed on the active matrix substrate so as to be sandwiched between two electrodes. By arranging multiple microcapsules, an active matrix display device is completed. Display can be achieved by applying an electric field to the cell. Active matrices obtained with thin-film transistors can be formed in a similar manner along with linear elements. A trix substrate can be used.

[0153] The first particles and the second particles in the microcapsules are made of a conductive material, an insulating material, Semiconductor materials, magnetic materials, liquid crystal materials, ferroelectric materials, electroluminescent materials, A material selected from the group consisting of magnetochromic material, magnetophoretic material, and a composite material thereof. Just use it.

[0154] According to this embodiment, a protection circuit is configured with a nonlinear element using an oxide semiconductor. As a result, it is possible to obtain a display device having a structure suitable for a protection circuit. In a connection structure between an oxide semiconductor layer and a wiring layer, the second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a region that is in contact with the second oxide semiconductor layer, compared to the case where only metal wiring is provided, This allows for stable operation, improving the functionality of the protection circuit and stabilizing operation. In this manner, according to the present embodiment, a highly reliable display device can be manufactured. In addition, by using the same configuration as in the third embodiment, the problem of peeling of the thin film can be prevented. A highly reliable display device equipped with a protection circuit made of nonlinear elements that are less prone to defects. It can be made.

[0155] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0156] (Embodiment 6) A thin film transistor is fabricated together with the nonlinear element according to one embodiment of the present invention, and the thin film transistor is imaged. A semiconductor device (also called a display device) having a display function is manufactured by using the semiconductor device in the element section and further in the driver circuit. In addition, the nonlinear element according to one embodiment of the present invention and a thin film transistor can be used as a driver circuit. It is used in part or in the whole of the device, and is integrated on the same substrate as the pixel section to form a system-on-panel. It is possible.

[0157] The display device includes a display element. The display element may be a liquid crystal element (also called a liquid crystal display element), a light-emitting A light-emitting element (also called a light-emitting display element) can be used. A light-emitting element is a light-emitting element that emits light by applying a current or a voltage. This category includes elements whose brightness is controlled by a specific factor, such as inorganic EL (Electroluminescent) devices. Also, electronic inks and other electronic devices A display medium in which the contrast changes due to thermal effects can also be used.

[0158] The display device includes a panel in which a display element is sealed, and a controller for the panel. and a module in which an IC or the like including the above-mentioned is mounted. Regarding the element substrate, which corresponds to one form before the display element is completed in the process of manufacturing a display device The element substrate includes a means for supplying a current to each of the plurality of pixels. Specifically, the substrate may be in a state where only pixel electrodes of the display element are formed, or the substrate may be in a state where only pixel electrodes of the display element are formed. After the conductive film that will become the electrode is formed, but before etching is performed to form the pixel electrode. It's fine to have one, and any form is acceptable.

[0159] In this specification, the term "display device" refers to an image display device, a display device, or an optical Also refers to connectors, such as FPC (Flexible Printed Circuit). inted circuit) or TAB (Tape Automated Bon ding tape or TCP (Tape Carrier Package) is used. Modules with printed wiring boards attached to the ends of TAB tape or TCP or the display element is mounted with an IC (integrated circuit) by the COG (Chip On Glass) method. The display device also includes all modules in which a display circuit (or other circuit) is directly mounted.

[0160] In this embodiment, the appearance of a liquid crystal display panel, which is one mode of a display device according to one embodiment of the present invention, will be described. The cross section will be described with reference to FIG. 17. FIG. 17 shows a nonlinear element and a method for forming a nonlinear element. Thin film transistors 4010 and 4011 with high electrical characteristics and liquid crystal elements 4013 that can be fabricated The first substrate 4001 and the second substrate 4006 are sealed with a sealant 4005. 17(A1) and (A2) are cross-sectional views of the panel. This corresponds to a surface view.

[0161] A pixel portion 4002 and a scanning line driver circuit 4004 are provided on a first substrate 4001. In this manner, a sealant 4005 is provided. A second substrate 4006 is provided on the path 4004. The line driver circuit 4004 is a sealing material 4 between a first substrate 4001 and a second substrate 4006. The first substrate 4001 is sealed together with the liquid crystal layer 4008 by a sealing material 4005. In an area different from the area surrounded by the insulating material 4005, a single A signal line driver circuit 4003 formed of a crystalline semiconductor film or a polycrystalline semiconductor film is mounted. .

[0162] The method of connecting the separately formed drive circuit is not particularly limited, and may be a COG method, A wire bonding method, a TAB method, or the like can be used. FIG. 17A shows an example of mounting a signal line driver circuit 4003 by the COG method. This is an example in which a signal line driver circuit 4003 is mounted by the TAB method.

[0163] A pixel portion 4002 and a scanning line driver circuit 4004 are provided on a first substrate 4001. In FIG. 17B, the thin film transistor included in the pixel portion 4002 A transistor 4010 and a thin film transistor 4011 included in the scanning line driver circuit 4004 Insulating layers 4020 and 4021 are formed on the thin film transistors 4010 and 4011. 1 is provided.

[0164] The thin film transistors 4010 and 4011 have a plasma-treated gate insulating layer and an oxygen-deficient A source region and a drain region made of an IGZO semiconductor film, and a source electrode layer and a drain electrode layer in contact with the source region and the drain region; A thin film transistor having an excess IGZO semiconductor layer and high electrical characteristics, The nonlinear element shown in FIG. 2 can be fabricated in the same manner. The transistors 4010 and 4011 are n-channel thin film transistors.

[0165] In addition, a pixel electrode layer 4030 of the liquid crystal element 4013 is connected to the thin film transistor 4010. The counter electrode layer 4031 of the liquid crystal element 4013 is electrically connected to the second substrate 40. 06. A pixel electrode layer 4030, a counter electrode layer 4031, and a liquid crystal layer 4008 are formed on the liquid crystal layer 4006. The overlapping portion corresponds to a liquid crystal element 4013. The electrode layer 4031 is provided with insulating layers 4032 and 4033 which function as alignment films. A liquid crystal layer 4008 is sandwiched between insulating layers 4032 and 4033 .

[0166] The first substrate 4001 and the second substrate 4006 may be made of glass or metal (typically, stainless steel). Stainless steel, ceramics, and plastics can be used. , FRP (Fiberglass-Reinforced Plastics) board, PV F (polyvinyl fluoride) film, polyester film or acrylic resin film Alternatively, you can use aluminum foil with a PVF film or polyester film. A sheet having a structure sandwiched between films can also be used.

[0167] Also, 4035 is a columnar spacer obtained by selectively etching the insulating film. In order to control the distance (cell gap) between the pixel electrode layer 4030 and the counter electrode layer 4031 A spherical spacer may also be used.

[0168] Alternatively, 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. When the temperature of cholesteric liquid crystal is increased, the phase immediately transitions from the cholesteric phase to the isotropic phase. The blue phase appears only in a narrow temperature range, so it is necessary to improve the temperature range. In order to achieve this, the liquid crystal layer 4008 is formed using a liquid crystal composition in which 5% by weight or more of a chiral agent is mixed. The liquid crystal composition containing the liquid crystal exhibiting the blue phase and the chiral agent has a response speed of 10 μs It is short (~100μs), does not require alignment treatment due to optical isotropy, and has low viewing angle dependency. Sai.

[0169] Note that this embodiment is an example of a transmissive liquid crystal display device, but one embodiment of the present invention is a reflective liquid crystal display device. The present invention can be applied to both liquid crystal display devices and semi-transmissive liquid crystal display devices.

[0170] In the liquid crystal display device of the present embodiment, a polarizing plate is provided on the outer side (the viewing side) of the substrate, and In this example, the color layer and the electrode layer used for the display element are provided in that order, but the polarizing plate is provided on the inner side of the substrate. In addition, the laminated structure of the polarizing plate and the colored layer is not limited to that of the present embodiment. The color layer may be appropriately selected depending on the material and manufacturing process conditions of the color layer. A light-shielding film that functions as a light-shielding film may be provided.

[0171] In this embodiment, in order to reduce the surface unevenness of the thin film transistor, In order to improve the reliability of the transistor, the nonlinear element shown in the second embodiment and the nonlinear element similar to the nonlinear element The thin film transistor can be formed by the above method. The protective film is covered with an insulating layer 4021 and an insulating layer 4022. It is a dense structure that prevents the intrusion of contaminating impurities such as floating organic matter, metals, and water vapor. The protective film is preferably a silicon oxide film, a silicon nitride film, or a silicon oxynitride film formed by sputtering. film, silicon nitride oxide film, aluminum oxide film, aluminum nitride film, aluminum oxynitride film The insulating film may be formed of a single layer or a stack of an aluminum nitride oxide film. Although an example of forming the protective film by sputtering is shown, the method is not particularly limited and may be formed by various methods. .

[0172] Here, an insulating layer 4020 having a laminated structure is formed as a protective film. A silicon oxide film is formed by sputtering as the first layer of the 0. Silicon oxide film as a protective film By using the above, it is possible to prevent hillocks in the aluminum film used as the source electrode layer and the drain electrode layer. It is effective in stopping.

[0173] In addition, a silicon nitride film is formed as a second layer of the insulating layer 4020 by sputtering. When a silicon nitride film is used as the film, mobile ions such as sodium ions penetrate into the semiconductor region, It is possible to suppress changes in the electrical characteristics of the TFT.

[0174] After forming the protective film, the IGZO semiconductor layer is annealed (300°C to 400°C). It is also possible.

[0175] In addition, an insulating layer 4021 is formed as a planarization insulating film. Heat-resistant organic compounds such as amide, acrylic, benzocyclobutene, polyamide, and epoxy. In addition to the above organic materials, low-k materials can be used. , siloxane resin, PSG (phosphorus glass), BPSG (borophosphorus glass), etc. are used. Siloxane-based resins can have hydrogen, fluorine, alkyl groups, or alkyl groups as substituents. In addition, the insulating material formed from these materials may have at least one of the following groups: The insulating layer 4021 may be formed by laminating a plurality of insulating films.

[0176] Siloxane-based resin is a type of Si-OS formed using siloxane-based materials as starting materials. Siloxane-based resins contain hydrogen, fluorine, alkyl, and aryl groups as substituents. The alkyl group may have at least one of a cyclic group, a cyclic group, or an aromatic hydrocarbon.

[0177] The method for forming the insulating layer 4021 is not particularly limited, and may be a sputtering method, an SOG method, or the like, depending on the material. , spin coating, dip coating, spray coating, droplet ejection method (inkjet method, screen printing, offset printing, etc.), doctor knife, roll coater, curtain coater, knife When the insulating layer 4021 is formed using a material liquid, The IGZO semiconductor layer can be annealed (at 300°C to 400°C) at the same time as the annealing process. The firing process of the insulating layer 4021 and the annealing process of the IGZO semiconductor layer are combined to efficiently It becomes possible to manufacture a semiconductor device.

[0178] The pixel electrode layer 4030 and the counter electrode layer 4031 are made of indium oxide containing tungsten oxide. , indium zinc oxide with tungsten oxide, indium oxide with titanium oxide, Indium tin oxide containing titanium oxide, indium tin oxide (hereinafter referred to as ITO), Translucent materials such as indium zinc oxide and indium tin oxide doped with silicon oxide A conductive material may be used.

[0179] The pixel electrode layer 4030 and the counter electrode layer 4031 are made of a conductive polymer. The conductive composition may be used to form the conductive film. The pixel electrode thus fabricated has a sheet resistance of 10,000 Ω / □ or less and a light transmittance of 550 nm. It is preferable that the resistance of the conductive polymer contained in the conductive composition is 70% or more. It is preferable that the electrical conductivity be 0.1 Ω·cm or less.

[0180] As the conductive polymer, a so-called π-electron conjugated conductive polymer can be used. For example, polyaniline or its derivatives, polypyrrole or its derivatives, polythiophene or or a derivative thereof, or a copolymer of two or more of these.

[0181] In addition, a signal line driver circuit 4003 and a scanning line driver circuit 4004 are formed separately, and a pixel portion 400 Various signals and potentials applied to 2 are supplied from FPC4018.

[0182] In this embodiment, the connection terminal electrode 4015 is connected to the pixel electrode layer 40 of the liquid crystal element 4013. The terminal electrode 4016 is formed from the same conductive film as the thin film transistors 4010 and 30. The source electrode layer and the drain electrode layer 11 are formed of the same conductive film.

[0183] The connection terminal electrode 4015 is connected to a terminal of the FPC 4018 via an anisotropic conductive film 4019. The electrodes are electrically connected to each other.

[0184] In FIG. 17, a signal line driver circuit 4003 is formed separately and mounted on a first substrate 4001. However, the present embodiment is not limited to this configuration. Alternatively, a part of the signal line driver circuit or a part of the scanning line driver circuit may be formed separately and mounted. Alternatively, the circuit board may be formed separately and mounted.

[0185] FIG. 18 shows a semiconductor device using a TFT substrate 2600 manufactured according to one embodiment of the present invention. 1 shows an example of a liquid crystal display module.

[0186] FIG. 18 shows an example of a liquid crystal display module, in which a TFT substrate 2600 and an opposing substrate 2601 are connected. The substrate 2602 is fixed to the substrate 2601 by a bonding material 2602, and a pixel portion 2603 including a TFT and the like and a liquid crystal layer are disposed between the substrate 2601 and the substrate 2602. A display element 2604 and a colored layer 2605 are provided to form a display area. is necessary for color display, and in the case of the RGB method, it corresponds to each color of red, green, and blue. A colored layer is provided corresponding to each pixel. On the outside, a polarizing plate 2606, a polarizing plate 2607, and a diffusion plate 2613 are arranged. It is composed of a cathode ray tube 2610 and a reflector 2611, and a circuit board 2612 is a flexible wiring board. A wiring board 2609 is connected to the wiring circuit section 2608 of the TFT board 2600, and the controller The LCD has external circuits such as a filter circuit and a power supply circuit. The layers may be laminated with a retardation plate interposed therebetween.

[0187] The LCD module is available in TN (Twisted Nematic) mode, IPS (In-plane Switching) mode, n-Plane-Switching mode, FFS (Fringe Field Switching) switching mode, MVA (Multi-domain Vertical A alignment) mode, PVA(Patterned Vertical Alignment) mode nment), ASM(Axially Symmetric aligned Mic) ro-cell) mode, OCB(Optical Compensated Bire) fringence mode, FLC (Ferroelectric Liquid C rystal) mode, AFLC (AntiFerroelectric Liquid Crystal) can be used.

[0188] According to this embodiment, a protection circuit is configured with a nonlinear element using an oxide semiconductor. As a result, it is possible to obtain a display device having a structure suitable for a protection circuit. In a connection structure between an oxide semiconductor layer and a wiring layer, the second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a region that is in contact with the second oxide semiconductor layer, compared to the case where only metal wiring is provided, This allows for stable operation, improving the functionality of the protection circuit and stabilizing operation. In this way, according to the present embodiment, a liquid crystal display device having high reliability as a display device can be obtained. A display panel can be manufactured by using the same structure as in the embodiment 3. This signal processing device is equipped with a protection circuit made of nonlinear elements that are less susceptible to defects caused by peeling of thin films. A highly reliable liquid crystal display panel can be manufactured.

[0189] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0190] (Embodiment 7) In this embodiment, an example of a light-emitting display device will be described as a display device according to one embodiment of the present invention. As the display element, a light-emitting element using electroluminescence is used as an example. The light-emitting element that utilizes electroluminescence uses an organic compound as the light-emitting material. Generally, the former are organic EL elements and the latter are inorganic compounds. These are called EL elements.

[0191] In an organic EL element, electrons and holes are released from a pair of electrodes by applying a voltage to the light-emitting element. are injected into layers containing light-emitting organic compounds, causing a current to flow. The rears (electrons and holes) recombine to form an excited state in the light-emitting organic compound. When the excited state returns to the ground state, light is emitted. Such a light-emitting element is called a current-excitation type light-emitting element.

[0192] Inorganic EL elements are divided into dispersion-type inorganic EL elements and thin-film-type inorganic EL elements according to their element structure. Dispersion-type inorganic EL elements have a light-emitting layer in which particles of a light-emitting material are dispersed in a binder. The emission mechanism is a donor-acceptor reaction that utilizes the donor and acceptor levels. Thin-film inorganic EL elements are made by sandwiching a light-emitting layer between dielectric layers. The structure is sandwiched between electrodes, and the light emission mechanism utilizes the inner shell electron transition of metal ions. In this example, the light-emitting element is an organic EL element. do.

[0193] FIG. 19 shows an example of a semiconductor device to which digital time gray scale driving is applied. FIG. 1 shows an example of a possible pixel configuration.

[0194] The configuration of a pixel to which digital time gray scale driving can be applied and the operation of the pixel will be described. The nonlinear element shown in the second or third embodiment is formed by using an IGZO semiconductor layer. Here is an example where two n-channel transistors are used in the channel forming region in one pixel. .

[0195] The pixel 6400 includes a switching transistor 6401, a driving transistor 6402, The switching transistor 64 has a light emitting element 6404 and a capacitor element 6403. 01 has a gate connected to a scanning line 6406 and a first electrode (one of the source and drain electrodes) The first electrode (the other of the source electrode and the drain electrode) is connected to a signal line 6405, and the second electrode (the other of the source electrode and the drain electrode) is connected to a drive The driving transistor 6402 is connected to the gate of the driving transistor 6402. The gate is connected to a power supply line 6407 via a capacitor element 6403, and the first electrode is connected to a power supply line 640 7, and the second electrode is connected to the first electrode (pixel electrode) of the light emitting element 6404. The second electrode of the light emitting element 6404 corresponds to a common electrode 6408 .

[0196] A low power supply potential is set to the second electrode (common electrode 6408) of the light emitting element 6404. Note that the low power supply potential is a low power supply potential with respect to the high power supply potential set to the power supply line 6407. Potential < High power supply potential. For example, GND, 0V, etc. are set as low power supply potential. The potential difference between the high power supply potential and the low power supply potential is applied to the light emitting element 6404. In order to make the light emitting element 6404 emit light by passing a current through the light emitting element 6404, a high power supply potential and the low power supply potential is set to be equal to or higher than the forward threshold voltage of the light emitting element 6404. Each potential is set.

[0197] The capacitor 6403 is omitted by substituting the gate capacitance of the driving transistor 6402. It is also possible to set the gate capacitance of the driving transistor 6402 as follows: A capacitance may be formed between the gate electrode and the second electrode.

[0198] In the case of a voltage input voltage driving method, the gate of the driving transistor 6402 is The driving transistor 6402 is in two states, either fully on or fully off. A video signal is inputted, that is, the driving transistor 6402 is operated in a linear region. In order to operate the driving transistor 6402 in a linear region, the voltage of the power supply line 6407 must be higher than that of the driving transistor 6402. A high voltage is applied to the gate of the driving transistor 6402. A voltage equal to or higher than (power supply line voltage + Vth of the driving transistor 6402) is applied.

[0199] In addition, when analog gray scale driving is performed instead of digital time gray scale driving, the input of the signal is different. By doing so, the same pixel configuration as in FIG. 19 can be used.

[0200] In the case of performing analog gradation driving, a light emitting element 6404 is connected to the gate of a driving transistor 6402. A voltage equal to or higher than the forward voltage of the light emitting element 6401 and the Vth of the driving transistor 6402 is applied. The forward voltage in 04 refers to the voltage required to achieve the desired brightness, and should be at least 100% forward voltage. In addition, the video transistor 6402 is designed to operate in the saturation region. By inputting an optical signal, a current can be passed through the light emitting element 6404. In order to operate the transistor 6402 in the saturation region, the potential of the power supply line 6407 is The gate potential of the light emitting element 6402 is set higher than that of the gate of the transistor 6403. Analog gradation drive can be performed by passing a current corresponding to a video signal through 6404.

[0201] Note that the pixel configuration shown in FIG. 19 is not limited to this. For example, A switch, a resistive element, a capacitive element, a transistor, a logic circuit, or the like may be added.

[0202] Next, the configuration of the light-emitting element will be described with reference to FIG. The cross-sectional structure of a pixel will be described using the example of the type shown in Figures 20(A), (B), and (C). The driving TFTs 7001, 7011, and 7021 used in the semiconductor device are the same as those in the second embodiment. A thin film transistor that can be formed in a similar manner to the nonlinear element shown in FIG. The gate insulating layer is made of an oxygen-deficient IGZO semiconductor film, and the source and drain regions are made of an oxygen-deficient IGZO semiconductor film. a source electrode layer and a drain electrode layer in contact with the source region and the drain region; A thin film transistor with high electrical properties having an oxygen-rich IGZO semiconductor layer in contact with the drain and gate regions is It is a transistor.

[0203] The light emitting element only needs to have at least one of the anode and cathode transparent in order to extract light. Then, a thin film transistor and a light emitting element are formed on the substrate, and light is taken from the surface opposite to the substrate. What is the difference between top emission, which emits light from the surface facing the substrate, and bottom emission, which emits light from the surface facing the substrate and the substrate? There is a light-emitting element having a dual emission structure in which light is emitted from the opposite surface. The composition can be applied to any light emitting device with any emission structure.

[0204] A light emitting element having a top emission structure will be described with reference to FIG.

[0205] In FIG. 20A, a driving TFT 7001 is an n-type TFT, and light emitted from a light-emitting element 7002 is A cross-sectional view of a pixel in the case where the light passes through to the anode 7005 side (the side opposite to the substrate) is shown in FIG. In this example, the cathode 7003 of the light emitting element 7002 is electrically connected to the driving TFT 7001. A light-emitting layer 7004 and an anode 7005 are laminated in this order on the cathode 7003. 3) Various materials can be used as long as they have a small work function and are conductive films that reflect light. For example, Ca, Al, CaF, MgAg, AlLi, etc. are preferable. And the light-emitting layer The 7004 may be constructed of a single layer or multiple layers may be laminated. In the case where the cathode 7003 is composed of a plurality of layers, an electron injection layer, an electron The transport layer, the light-emitting layer, the hole transport layer, and the hole injection layer are laminated in this order. The anode 7005 is formed using a light-transmitting conductive material. , for example, indium oxide containing tungsten oxide, indium oxide containing tungsten oxide Zinc oxide, indium oxide with titanium oxide, indium tin oxide with titanium oxide Indium tin oxide (hereinafter referred to as ITO), indium zinc oxide, and silicon oxide A light-transmitting conductive film such as an indium tin oxide film containing doped indium tin may be used.

[0206] The region where the light-emitting layer 7004 is sandwiched between the cathode 7003 and the anode 7005 constitutes the light-emitting element 7002. In the case of the pixel shown in FIG. 20(A), the light emitted from the light emitting element 7002 is The light is emitted toward the anode 7005 as indicated by the mark.

[0207] Next, a light emitting element having a bottom emission structure will be described with reference to FIG. 011 is an n-type, and light emitted from the light-emitting element 7012 is emitted to the cathode 7013 side (substrate side). FIG. 20B shows a cross-sectional view of a pixel when the driving TFT 7011 and the A cathode 7013 of a light-emitting element 7012 is formed on the connected conductive film 7017 having light-transmitting properties. A light-emitting layer 7014 and an anode 7015 are laminated in this order on the cathode 7013. In the case where the anode 7015 is transparent, a light reflecting or blocking layer is provided so as to cover the anode. A shielding film 7016 for preventing the cathode from being damaged may be formed. The cathode 7013 is the same as that in FIG. Similarly, various conductive materials with small work functions can be used. The film thickness is set to a level that allows light to pass through (preferably, about 5 nm to 30 nm). For example, An aluminum film having a thickness of 0 nm can be used as the cathode 7013. The light-emitting layer 7014 may be composed of a single layer as in FIG. 20(A), or may be composed of multiple layers. The anode 7015 does not need to transmit light. However, as in FIG. 20(A), it can be formed using a conductive material having light transmitting properties. The shielding film 7016 can be made of, for example, a metal that reflects light. The material is not limited to a film, and for example, a resin to which a black pigment is added may be used.

[0208] The region where the light-emitting layer 7014 is sandwiched between the cathode 7013 and the anode 7015 is the light-emitting element 7012. In the case of the pixel shown in FIG. 20B, the light emitted from the light-emitting element 7012 corresponds to The light is emitted toward the cathode 7013 as shown by the arrow.

[0209] Next, a light emitting element having a dual emission structure will be described with reference to FIG. In this example, a conductive film 7027 having a light-transmitting property and electrically connected to the driving TFT 7021 is formed on the substrate 7022. A cathode 7023 of the light-emitting element 7022 is formed, and a light-emitting layer 7024 is formed on the cathode 7023. The anode 7025 is laminated in order. The cathode 7023 is, as in the case of FIG. Various conductive materials with small thermal coefficients can be used. However, the thickness of the material should be For example, the cathode 7023 is made of Al having a thickness of 20 nm. The light-emitting layer 7024 can be formed of a single layer, as in FIG. The anode 70 may be configured as a single layer or as a laminate of multiple layers. 25 is formed using a conductive material having a light transmitting property, similar to FIG. It is possible.

[0210] The overlapping portion of the cathode 7023, the light-emitting layer 7024, and the anode 7025 constitutes the light-emitting element 70. In the case of the pixel shown in FIG. 20C, the light emitted from the light emitting element 7022 is is emitted toward both the anode 7025 side and the cathode 7023 side as indicated by the arrows.

[0211] Although the organic EL element has been described as the light-emitting element here, inorganic EL elements can also be used as the light-emitting element. It is also possible to provide an L element.

[0212] In this embodiment, a thin film transistor (driving TFT) that controls driving of a light emitting element is Although an example in which the light-emitting element is electrically connected has been shown, the current between the driving TFT and the light-emitting element is A control TFT may be connected.

[0213] Note that the semiconductor device described in this embodiment mode is not limited to the configuration shown in FIG. Various modifications based on the technical concept of the present invention are possible.

[0214] Next, a light-emitting display panel (also called a light-emitting panel) which is one embodiment of a semiconductor device of one embodiment of the present invention will be described. The appearance and cross section of the present invention will be described with reference to FIG. A thin film transistor having high electrical properties can be fabricated on the first substrate in a similar manner together with the nonlinear element of the embodiment. A panel in which a transistor and a light-emitting element are sealed with a sealant between a first substrate and a second substrate. 21(B) is a top view of the device, and FIG. 21(B) is a cross-sectional view taken along line HI in FIG. 21(A).

[0215] A pixel portion 4502, a signal line driver circuit 4503a, and a signal line driver circuit 4504 are provided on a first substrate 4501. A sealant 4505 is formed to surround the gate driver circuits 4504a and 4504b. In addition, a pixel portion 4502, signal line driver circuits 4503a and 4503b, and A second substrate 4506 is provided on the scanning line driver circuits 4504a and 4504b. The pixel portion 4502, the signal line driver circuits 4503a and 4503b, and the scanning line driver circuit 45 4504a and 4504b are a first substrate 4501, a sealant 4505, and a second substrate 4506. The filling material 4507 is sealed with the sealing material 4507. Highly sealed protective film with little outgassing (lamination film, UV curable resin film) It is preferable to package (enclose) the package in a material such as a film or a cover material.

[0216] In addition, a pixel portion 4502, a signal line driver circuit 4503a, The scanning line driver circuits 4503a and 4504b each have a plurality of thin film transistors. In FIG. 21B, a thin film transistor 4510 included in a pixel portion 4502 and A thin film transistor 4509 included in a signal line driver circuit 4503a is illustrated.

[0217] The thin film transistors 4509 and 4510 have a plasma-treated gate insulating layer and an oxygen-deficient The source region and the drain region are made of an IGZO semiconductor film. a source electrode layer and a drain electrode layer in contact with the source region and the drain region; A thin film transistor having high electrical characteristics and an IGZO semiconductor layer with excess silicon, The nonlinear element shown in the embodiment 2 can be fabricated in the same manner. Transistors 4509 and 4510 are n-channel thin film transistors.

[0218] In addition, 4511 corresponds to a light-emitting element, and a first electrode which is a pixel electrode of the light-emitting element 4511 is The layer 4517 is electrically connected to the source electrode layer or the drain electrode layer of the thin film transistor 4510. The light-emitting element 4511 is configured as a first electrode layer 4517, an electroluminescent layer The first electrode layer 4512 and the second electrode layer 4513 are stacked in a stacked structure. The light emitting element 4511 is not rotated in accordance with the direction of the light to be extracted from the light emitting element 4511. The configuration can be changed as appropriate.

[0219] The partition 4520 is formed using an organic resin film, an inorganic insulating film, or an organic polysiloxane. In particular, a photosensitive material is used to form an opening on the first electrode layer 4517, and the sidewall of the opening It is preferable that the inclined surface is formed so as to have a continuous curvature.

[0220] The electroluminescent layer 4512 may be composed of a single layer or a plurality of layers may be laminated. It doesn't matter whether it is done or not.

[0221] In order to prevent oxygen, hydrogen, moisture, carbon dioxide, and the like from entering the light-emitting element 4511, the second electrode layer A protective film may be formed on the partition wall 4513 and the partition wall 4520. The protective film may be a silicon nitride film, A silicon oxynitride film, DLC film, etc. can be formed.

[0222] In addition, signal line driver circuits 4503a and 4503b, scanning line driver circuits 4504a and 4504b Various signals and potentials applied to the pixel portion 4502 are It is supplied by b.

[0223] In this embodiment, the connection terminal electrode 4515 is connected to the first electrode layer 4 of the light emitting element 4511. The terminal electrode 4516 is formed from the same conductive film as the thin film transistors 4509 and 517. The source electrode layer and the drain electrode layer 510 are formed from the same conductive film.

[0224] The connection terminal electrode 4515 is connected to the terminal of the FPC 4518a via the anisotropic conductive film 4519. The electrodes are electrically connected to each other.

[0225] The second substrate 4506 located in the direction in which light is extracted from the light emitting element 4511 must be transparent. In this case, a glass plate, a plastic plate, a polyester film or A light-transmitting material such as an acrylic film is used.

[0226] In addition, filler 4507 can be inert gas such as nitrogen or argon, or ultraviolet-curing resin. It can be made of oil or thermosetting resin, and can be made of PVC (polyvinyl chloride), acrylic, Polyimide, epoxy resin, silicone resin, PVB (polyvinyl butyral) or EV A (ethylene vinyl acetate) can be used. In this embodiment, nitrogen is used as the filler. Use element.

[0227] If necessary, a polarizing plate or a circular polarizing plate (including an elliptical polarizing plate) may be provided on the light-emitting surface of the light-emitting element. Optical films such as retardation plates (λ / 4 plates, λ / 2 plates) and color filters may be provided as appropriate. In addition, the polarizing plate or the circular polarizing plate may be provided with an anti-reflection film. Anti-glare treatment can be applied to diffuse reflected light and reduce glare.

[0228] The signal line driver circuits 4503a and 4503b and the scanning line driver circuits 4504a and 4504b are A driving circuit formed of a single crystal semiconductor film or a polycrystalline semiconductor film on a separately prepared substrate is Also, only the signal line driver circuit, or a part of the signal line driver circuit, or the scanning line driver circuit may be mounted. Only the path or only a part of the path may be separately formed and mounted. In this embodiment, the structure shown in FIG. Not limited.

[0229] According to this embodiment, a protection circuit is configured with a nonlinear element using an oxide semiconductor. As a result, it is possible to obtain a display device having a structure suitable for a protection circuit. In a connection structure between an oxide semiconductor layer and a wiring layer, the second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a region that is in contact with the second oxide semiconductor layer, compared to the case where only metal wiring is provided, This allows for stable operation, improving the functionality of the protection circuit and stabilizing operation. In this way, according to the present embodiment, it is possible to provide a highly reliable light emitting device as a display device. A display device (display panel) can be manufactured. A protection circuit made of nonlinear elements that is less susceptible to failures caused by peeling of thin films. It is possible to manufacture a highly reliable light-emitting display device (display panel) incorporating the above.

[0230] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0231] (Embodiment 8) The display device of one embodiment of the present invention can be used as electronic paper. It can be used in any electronic device that displays information. For example, electronic paper can be used for electronic books, posters, and on trains and other vehicles. It can be used for in-car advertising, display on various cards such as credit cards, etc. An example of a child device is shown in FIG. 22 and FIG.

[0232] FIG. 22(A) shows a poster 2631 made of electronic paper. In the case of printed matter, the advertisements are exchanged manually. By using electronic paper, the display of advertisements can be changed in a short time. The poster is designed to transmit and receive information wirelessly. It is also possible to use the following.

[0233] FIG. 22(B) shows an advertisement 2632 on a train or other vehicle. In the case of paper prints, the advertisements are exchanged manually. By using electronic paper, it is possible to change the display of advertisements in a short time without requiring a lot of manpower. In addition, stable images can be obtained without display distortion. The configuration may be such that information can be transmitted and received.

[0234] FIG. 23 also shows an example of an electronic book 2700. For example, the electronic book 2700 is The device is made up of two housings, a housing 2701 and a housing 2703. The body 2703 is integrated with a shaft portion 2711, and the opening and closing movement is performed around the shaft portion 2711. This configuration allows the device to operate like a paper book. It becomes.

[0235] A display unit 2705 is incorporated in the housing 2701, and a display unit 2707 is incorporated in the housing 2703. The display unit 2705 and the display unit 2707 are configured to display a continuous screen. Alternatively, a different screen may be displayed. For example, a text is displayed on the right display (display 2705 in FIG. 23) and An image can be displayed on the display unit 2707 in FIG.

[0236] FIG. 23 shows an example in which the housing 2701 is provided with an operation unit. 701, a power supply 2721, operation keys 2723, a speaker 2725, etc. The operation keys 2723 can be used to turn pages. The configuration may include a touch panel, a touch screen, a pointing device, etc. On the side, there are external connection terminals (earphone terminal, USB terminal, or AC adapter and USB A configuration including a terminal that can be connected to various cables such as a cable, a recording medium insertion section, etc. Furthermore, the electronic book 2700 may be configured to have a function as an electronic dictionary. This is also fine.

[0237] The electronic book 2700 may be configured to transmit and receive information wirelessly. The desired book data can be purchased and downloaded from the electronic book server. is also possible.

[0238] As in this embodiment, the function of a nonlinear element using an oxide semiconductor is improved and the operation is stabilized. By mounting a display device having a protection circuit on an electronic device, the electronic device can be made more reliable. In addition, by using the same configuration as in the third embodiment, the peeling of the thin film can be prevented. Highly reliable display device equipped with a protection circuit made of nonlinear elements that are less susceptible to defects caused by It is possible to manufacture electronic devices equipped with the above.

[0239] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0240] (Embodiment 9) A semiconductor device according to one embodiment of the present invention can be applied to various electronic devices (including game machines). The electronic device can be, for example, a television device (television or television (also called digital receivers), computer monitors, digital cameras, digital video cameras, etc. digital photo frames, mobile phones (also called mobile phones or mobile phone devices), These include large game machines such as small game machines, portable information terminals, audio playback devices, and pachinko machines. can be.

[0241] FIG. 24A shows an example of a television device 9600. The display unit 9603 is incorporated in the housing 9601. In addition, the stand 9605 supports the housing 9601. This shows a configuration in which the above is supported.

[0242] The television device 9600 can be operated using an operation switch on the housing 9601 or a separate remote control. This can be done by the remote control operation device 9610. The channel and volume can be controlled by the 9609, and the display 9603 shows In addition, the remote control unit 9610 can control the video. A display portion 9607 for displaying information output from 9610 may be provided.

[0243] The television device 9600 includes a receiver and a modem. It can receive more general television broadcasts, and can also be connected to a modem via wired or wireless connection. By connecting to a network, communication can be one-way (sender to receiver) or two-way. It is also possible to communicate information (between a sender and a receiver, or between receivers).

[0244] FIG. 24B shows an example of a digital photo frame 9700. The photo frame 9700 includes a display unit 9703 built into a housing 9701. The unit 9703 is capable of displaying various images, for example images captured by a digital camera. By displaying the image data, it can function like a normal photo frame.

[0245] The Digital Photo Frame 9700 is equipped with an operation unit, external connection terminals (USB terminal, US A terminal that can be connected to various cables such as B cable, etc., and a recording medium insertion section, etc. These components may be installed on the same surface as the display unit, but they may be installed on the side or back. It is preferable to have a digital photo frame with a built-in memory card because it improves the design. A memory that stores image data taken with a digital camera is inserted into the body insertion section. The captured image data can be displayed on the display portion 9703 .

[0246] The digital photo frame 9700 may also be configured to transmit and receive information wirelessly. It is also possible to wirelessly import and display desired image data.

[0247] FIG. 25(A) shows a portable gaming machine, which is composed of two housings, a housing 9881 and a housing 9891. The housing 9881 is connected to a connector 9893 so as to be openable and closable. A display unit 9883 is incorporated in the housing 9891. The portable gaming machine shown in FIG. 25(A) also includes a speaker unit 9884 and a recording medium insertion unit 988. 6, LED lamp 9890, input means (operation keys 9885, connection terminals 9887, sensors 9 888 (force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, Chemicals, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration 9889) equipped with a microphone, etc. Of course, the configuration of the portable gaming machine is not limited to the above, and at least the present invention It is sufficient that the semiconductor device according to the present invention is included, and other auxiliary equipment is appropriately provided. The portable game machine shown in FIG. 25(A) can be configured as a game machine having a game data recorded on a recording medium. The function of reading out programs or data and displaying them on the display unit, as well as wireless communication with other portable gaming machines, The portable gaming machine shown in FIG. 25(A) has a function of communicating with the user and sharing information. The functions are not limited to these, and the device may have a variety of functions.

[0248] FIG. 25(B) shows an example of a slot machine 9900, which is a large-scale gaming machine. The machine 9900 has a display unit 9903 built into a housing 9901. The Machine 9900 also includes other operating means such as a start lever and stop switch, coin The slot machine 9900 is equipped with a slot slot, a speaker, etc. However, the present invention is not limited to the above, and may be implemented in any configuration including at least a semiconductor device according to one embodiment of the present invention. In addition, other auxiliary equipment may be provided as appropriate.

[0249] FIG. 26 shows an example of a mobile phone 1000. The mobile phone 1000 has a housing 100 In addition to the display unit 1002 incorporated in the device 1, the device 1002 also includes an operation button 1003, an external connection port 1004, It is equipped with a speaker 1005, a microphone 1006, etc.

[0250] The mobile phone 1000 shown in FIG. 26 allows users to input information by touching the display unit 1002 with a finger or the like. In addition, operations such as making a phone call or typing an e-mail can be performed by the display unit 100. This can be done by touching 2 with a finger or other object.

[0251] The screen of the display unit 1002 has three main modes. The first is a display mode that is mainly used for displaying images. The first mode is a display mode, the second is an input mode for inputting information such as characters, and the third mode is a display mode. This is a display + input mode that combines the display mode and the input mode.

[0252] For example, when making a call or composing an e-mail, the display unit 1002 is used for inputting characters. The main character input mode is to input characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display unit 1002. I wish.

[0253] In addition, a sensor for detecting tilt, such as a gyro or an acceleration sensor, is installed inside the mobile phone 1000. By providing a detection device having the above configuration, the orientation of the mobile phone 1000 (portrait or landscape) can be determined and the display The screen display of the display unit 1002 can be automatically switched.

[0254] The screen mode can be changed by touching the display unit 1002 or by operating the housing 1001. This is done by operating the button 1003. Also, depending on the type of image displayed on the display unit 1002, For example, the image signal to be displayed on the display unit is a moving image. If it is data, the mode is switched to display mode, and if it is text data, the mode is switched to input mode.

[0255] In the input mode, the optical sensor of the display unit 1002 detects a signal and displays If there is no input by touch operation of the part 1002 for a certain period of time, the screen mode is changed to the input mode. Alternatively, the display mode may be switched from the normal mode to the display mode.

[0256] The display unit 1002 can also function as an image sensor. By touching the palm or fingers to the sensor 02, the palm print, fingerprint, etc. can be captured and identity authentication can be performed. In addition, the display unit may be equipped with a backlight that emits near-infrared light or a sensor that emits near-infrared light. By using a scanning light source, it is also possible to image finger veins, palm veins, etc.

[0257] As in this embodiment, the function of a nonlinear element using an oxide semiconductor is improved and the operation is stabilized. By mounting a display device having a protection circuit on an electronic device, the electronic device can be made more reliable. In addition, by using the same configuration as in the third embodiment, the peeling of the thin film can be prevented. Highly reliable display device equipped with a protection circuit made of nonlinear elements that are less susceptible to defects caused by It is possible to manufacture electronic devices equipped with the above.

[0258] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is. [Explanation of symbols]

[0259] 10 Substrate 11 Scan line input terminal 12 Signal line input terminal 13 Scan Lines 14 Signal Line 15 Gate electrode 16 Gate electrode 17 Pixel section 18 pixels 19 Pixel transistor 20 Holding capacity section 21 Pixel electrode 22 Capacitor Line 23 Common terminal 24 Protection circuit 25 Protection circuit 26 Protection circuit 27 Capacitive bus line 28 Common Wiring 29 Common Wiring 30 Nonlinear elements 30a Nonlinear element 30b Nonlinear elements 31 Nonlinear elements 31a Nonlinear elements 31b Nonlinear elements 36 Oxide semiconductor layer 37 Gate insulation layer 38 wiring layer 39 Wiring layer 40 Oxide semiconductor layer 41 Conductive layer 42 Interlayer insulation layer 43 Contact Hole 44 Wiring layer 100 Substrates 101 Gate electrode 102 Gate insulating layer 103 Oxide semiconductor layer 104a Source Area 104b Drain region 105a Source electrode layer 105b Drain electrode layer 106a Source Area 106b Drain region 107 Protective insulating film 108 scan lines 111a Oxide semiconductor layer 125 Contact Hole 126 Contact Hole 128 wiring layer 580 Substrate 581 Thin Film Transistor 583 Interlayer insulating film 584 Insulating Layer 585 Insulation Layer 587 Electrode layer 588 Electrode layer 589 Spherical particles 590a black area 590b White area 594 Cavity 595 Filling material 596 Board 650 scan lines 651 Common Wiring 730a Nonlinear element 730b Nonlinear elements 730c Nonlinear element 740a Nonlinear element 740b Nonlinear element 740c Nonlinear element 740d Nonlinear element 1000 Mobile Phones 1001 Case 1002 Display section 1003 Operation button 1004 External connection port 1005 Speaker 1006 Mike 2600 TFT substrate 2601 Opposing substrate 2602 Sealing material 2603 Pixel section 2604 Display element 2605 Colored layer 2606 Polarizing plate 2607 Polarizing plate 2608 Wiring circuit section 2609 Flexible wiring board 2610 cold cathode tube 2611 Reflector 2612 Circuit Board 2613 Diffuser 2631 Poster 2632 In-car advertising 2700 e-books 2701 Case 2703 Case 2705 ​​Display section 2707 Display section 2711 Shaft 2721 Power supply 2723 Operation key 2725 Speaker 4001 Board 4002 Pixel section 4003 Signal line driver circuit 4004 Scanning line driver circuit 4005 Sealing material 4006 Substrate 4008 Liquid crystal layer 4010 Thin film transistor 4011 Thin film transistor 4013 Liquid crystal element 4015 Connection terminal electrode 4016 Terminal electrode 4018 FPC 4019 Anisotropic conductive film 4020 Insulation layer 4021 Insulation layer 4030 Pixel electrode layer 4031 Counter electrode layer 4032 Insulation layer 4033 Insulation layer 4035 Spacer 4501 Board 4502 Pixel section 4503a Signal line driver circuit 4503b Signal line driver circuit 4504a Scanning line driver circuit 4503b Signal line driver circuit 4505 Sealing material 4506 Board 4507 Filling material 4509 Thin-film transistor 4510 Thin-film transistor 4511 Light emitting element 4512 Electroluminescent layer 4513 Electrode layer 4515 Connection terminal electrode 4516 Terminal electrode 4517 Electrode layer 4518a FPC 4518b FPC 4519 Anisotropic conductive film 4520 Bulkhead 5300 Board 5301 Pixel unit 5302 Scanning line driver circuit 5303 Signal line driver circuit 5400 Board 5401 Pixel unit 5402 Scanning line driver circuit 5403 Signal line driver circuit 5404 Scanning line driver circuit 5501 Wiring 5502 Wiring 5503 Wiring 5504 Wiring 5505 Wiring 5506 Wiring 5543 nodes 5544 nodes 5571 Thin-film transistor 5572 Thin Film Transistor 5573 Thin Film Transistor 5574 Thin Film Transistor 5575 Thin Film Transistor 5576 Thin Film Transistor 5577 Thin Film Transistor 5578 Thin Film Transistor 5601 Driver IC 5602 Switches 5603a Thin Film Transistor 5603b Thin Film Transistor 5603c Thin Film Transistor 5611 Wiring 5612 Wiring 5613 Wiring 5621 Wiring 5701 Flip-flop 5703a Timing 5703b Timing 5703c Timing 5711 Wiring 5712 Wiring 5713 Wiring 5714 Wiring 5715 Wiring 5716 Wiring 5717 Wiring 5721 Signal 5803a Timing 5803b Timing 5803c Timing 5821 Signal 6400 pixels 6401 Switching transistor 6402 Driving transistor 6403 Capacitor 6404 Light emitting element 6405 Signal Line 6406 scan lines 6407 Power line 6408 Common electrode 7001 Driving TFT 7002 Light emitting element 7003 Cathode 7004 Light-emitting layer 7005 Anode 7011 Driving TFT 7012 Light emitting element 7013 Cathode 7014 Light-emitting layer 7015 Anode 7016 Shielding membrane 7017 Conductive film 7021 Driving TFT 7022 Light emitting element 7023 Cathode 7024 Light-emitting layer 7025 Anode 7027 Conductive film 9600 Television Equipment 9601 Case 9603 Display section 9605 Stand 9607 Display section 9609 Operation key 9610 Remote control device 9700 Digital Photo Frame 9701 Case 9703 Display section 9881 Case 9882 Display section 9883 Display section 9884 Speaker section 9885 Operation key 9886 Recording medium insertion section 9887 Connection terminal 9888 Sensor 9889 Microphone 9890 LED Lamp 9891 Case 9893 Connection section 9900 Slot Machine 9901 Case 9903 Display section

Claims

1. A pixel unit and a protection circuit on the outside of the pixel unit, The protection circuit is a display device having a first transistor and a second transistor, a first conductive layer having a region functioning as one of a source electrode and a drain electrode of the first transistor has a region functioning as the other of a source electrode and a drain electrode of the second transistor; a second conductive layer having a region functioning as the other of a source electrode or a drain electrode of the first transistor, the second conductive layer having a region functioning as one of a source electrode or a drain electrode of the second transistor, a third conductive layer having a region functioning as a gate electrode of the first transistor; a fourth conductive layer having a region that functions as a gate electrode of the second transistor; the first conductive layer is electrically connected to the third conductive layer through a first contact opening; the second conductive layer is electrically connected to the fourth conductive layer through a second contact opening; the first conductive layer has a region intersecting with the fourth conductive layer in a plan view, In a plan view, the first conductive layer does not have a region that intersects with the second conductive layer, In a plan view, the first conductive layer does not have a region that intersects with the third conductive layer, In a plan view, the first conductive layer has a region extending in a first direction, In a plan view, the fourth conductive layer has a region extending in a second direction intersecting the first direction, a channel formation region of the first transistor has a portion located between the first contact opening and a channel formation region of the second transistor in the first direction in a plan view; A display device, in the first direction when viewed in a plan view, wherein a channel formation region of the second transistor has a portion located between a region where the fourth conductive layer extends in the second direction and a channel formation region of the first transistor.

2. A pixel unit and a protection circuit on the outside of the pixel unit, The protection circuit is a display device having a first transistor and a second transistor, a first conductive layer having a region functioning as one of a source electrode and a drain electrode of the first transistor has a region functioning as the other of a source electrode and a drain electrode of the second transistor; a second conductive layer having a region functioning as the other of a source electrode or a drain electrode of the first transistor, the second conductive layer having a region functioning as one of a source electrode or a drain electrode of the second transistor, a third conductive layer having a region functioning as a gate electrode of the first transistor; a fourth conductive layer having a region that functions as a gate electrode of the second transistor; the first conductive layer is electrically connected to the third conductive layer through a first contact opening; the second conductive layer is electrically connected to the fourth conductive layer through a second contact opening; the first conductive layer has a region intersecting with the fourth conductive layer in a plan view, In a plan view, the first conductive layer does not have a region that intersects with the second conductive layer, In a plan view, the first conductive layer does not have a region that intersects with the third conductive layer, In a plan view, the first conductive layer has a region extending in a first direction, In a plan view, the fourth conductive layer has a region extending in a second direction intersecting the first direction, a channel formation region of the first transistor has a portion located between the first contact opening and a channel formation region of the second transistor in the first direction in a plan view; a channel formation region of the second transistor has a portion located between a region where the fourth conductive layer extends in the second direction and a channel formation region of the first transistor in the first direction in a plan view; a channel formation region of the first transistor includes a first oxide semiconductor; A display device, wherein a channel formation region of the first transistor includes a second oxide semiconductor.

Images