Liquid crystal display device

Abstract

To provide a liquid crystal display device using an oxide semiconductor, including a protection circuit which has improved functions, operates stably, and has a reduced occupancy area.SOLUTION: The protection circuit comprises: a gate insulation film 102 covering a gate electrode 111; a first oxide semiconductor layer 113 overlapping the gate electrode on the gate insulation film; a channel protection layer 116 covering a region overlapping a channel formation region of the first oxide semiconductor layer; and a nonlinear element 170a which has ends overlapping the gate electrode on the first oxide semiconductor layer, and a first wiring layer 117a and a second wiring layer 117b on which conductive layers 115a, 115b and second oxide semiconductor layers 114a, 114b are stacked. The gate electrode of the nonlinear element is connected to a scan line 13 or a signal line. The first wiring layer or the second wiring layer of the nonlinear element for applying potential of the gate electrode is directly connected to the gate electrode. Thus, the operation is stabilized due to reduction in connection resistance and the occupancy area by the connection part is reduced.SELECTED DRAWING: Figure 5

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 crystalline 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. A thin film transistor is fabricated using an oxide semiconductor containing indium, gallium, and zinc. The technology for manufacturing the semiconductor device and using it as a switching element for an image display device is described in Patent Documents 1 and 2. It has been disclosed. [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, even if the process temperature is low, such as from room temperature to 300°C or less, the field effect migration It is therefore possible to fabricate thin film transistors with high uniformity.

[0006] By utilizing the characteristics of display devices that use oxide semiconductors, which have excellent operating characteristics and can be manufactured at low temperatures, we have achieved high reliability. In order to guarantee this, a protection circuit with an appropriate configuration is required. In order to achieve miniaturization, it is necessary to reduce the area occupied by the protection circuit.

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

[0008] The present invention relates to a display device for various applications that is manufactured by laminating an insulating film and a conductive film in addition to an oxide semiconductor. In this device, the function of the protection circuit is improved to stabilize the operation and reduce the area occupied by the protection circuit. One of the objectives of the organization is to [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. At least one of the first wiring layer and the second wiring layer of the nonlinear element is formed. The gate electrode is directly connected to the wiring formed in the same process as the gate wiring layer. .

[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. a gate insulating layer covering the gate electrode and the gate electrode; a first oxide semiconductor layer overlapping a gate electrode; and a channel formation region of the first oxide semiconductor layer. a channel protection layer covering an area overlapping the gate electrode; and The conductive layer and the second oxide semiconductor layer are laminated such that the ends of the conductive layer and the second oxide semiconductor layer overlap and are in contact with the first oxide semiconductor layer. The first wiring layer and the second wiring layer are electrically conductive. The gate electrode of the nonlinear element is in contact with the first oxide semiconductor layer through the second oxide semiconductor layer. The first wiring layer or the second wiring layer of the nonlinear element is connected to the scan line or the signal line, and the potential of the gate electrode It is directly connected to the gate electrode or the wiring layer formed in the same layer as the gate electrode so that It has been done.

[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; The second wiring layer is in contact with the oxide semiconductor layer. A protection circuit that connects the wiring and a protection circuit that connects the signal line and the common wiring are provided. The protection circuit includes a gate electrode and a gate insulating layer covering the gate electrode. a first oxide semiconductor layer overlapping the gate electrode on the first oxide semiconductor layer; a channel protection layer covering a region overlapping with the channel formation region; a conductive layer and a second oxide semiconductor layer, the conductive layer and the second oxide semiconductor layer being overlapped with the gate electrode and in contact with the first oxide semiconductor layer; The nonlinear element has a first wiring layer and a second wiring layer in which a body layer is laminated. The conductive layers of the first and second wiring layers of the nonlinear element of the protection circuit are made of a second oxide semiconductor. The gate electrode is in contact with the first oxide semiconductor layer through a gate electrode layer. The wiring is directly connected to the first wiring layer or the second wiring layer.

[0012] 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 Effect of the Invention

[0013] 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, the second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a region where the second oxide semiconductor layer has a high thermal conductivity, stable operation can be achieved. This makes it possible to improve the functionality of the protection circuit and stabilize operation.

[0014] Also, a contact hole reaching the first wiring layer or the second wiring layer and a gate electrode or A contact hole is provided that reaches the wiring formed in the same layer as the first electrode, and the first wiring is formed in a different wiring layer. A method for connecting a first wiring layer or a second wiring layer to a gate electrode or a wiring formed in the same layer as the gate electrode However, when this method is used, two interfaces and two contact holes are required for one connection. is formed.

[0015] The nonlinear element constituting the protection circuit according to one embodiment of the present invention is a conductive layer of the first wiring layer or the second wiring layer. Since the gate electrode is directly connected to the gate electrode or the wiring formed in the same layer as the gate electrode, The interface and the contact hole formed in the connection are only one each. Since there is only one interface, the contact resistance can be reduced compared to the method of connecting via a separate wiring layer. As a result, the protection circuit using the nonlinear element operates stably. Since only one contact hole is required, the connection is easier than the method of connecting via a separate wiring layer. As a result, the area occupied by the protection circuit is reduced, The display device can be made smaller. [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 is a diagram showing an example of a protection circuit. [Diagram 3] FIG. 13 is a diagram showing 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] FIG. 4 is a plan view showing an example of a protection circuit. [Figure 9] FIG. 4 is a plan view showing an example 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 one embodiment of the present invention. [Figure 18] FIG. 1 is a cross-sectional view illustrating a semiconductor device of one embodiment of the present invention. [Figure 19] FIG. 2 illustrates a pixel equivalent circuit of a semiconductor device of one embodiment of the present invention. [Figure 20] 1A to 1C illustrate a semiconductor device of one embodiment of the present invention. [Figure 21] 1A and 1B are a top view and a cross-sectional view illustrating a semiconductor device of one embodiment of the present invention. [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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention will be described below with reference to the drawings. The present invention is not limited to the above, and various forms and details may be used without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that the present invention can be modified in various ways. The present invention is not limited to the description of the embodiments. In the drawings, the same reference numerals are used to refer to the same parts.

[0018] (Embodiment 1) In this embodiment, a display device is provided in which a pixel section and a protection circuit including a nonlinear element are formed in the periphery of the pixel section. One embodiment of the present invention will be described 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 capacitors. A surge voltage is applied to the bus line 27 due to static electricity or the like, and the pixel transistors 19 and other components are destroyed. Therefore, when a surge voltage is applied to the protection circuit, It is configured to release electric charge to the common wiring 29 or the common wiring 28 .

[0023] In this embodiment, the protection circuits 24, 25, and 26 are provided in the display device. However, the configuration of the protection circuit is not limited to this.

[0024] FIG. 2 shows an example of a protection circuit. This protection circuit is connected in parallel between the scanning line 13 and the common line 29. The nonlinear element 30 is configured by a nonlinear element 31 arranged in the nonlinear element 30. The nonlinear element 31 is a two-terminal element such as a diode or a three-terminal element such as a transistor. For example, it can be formed in the same process as the pixel transistors in the pixel area. For example, by connecting the gate terminal and the drain terminal, the device has the same characteristics as a diode. It is possible to have.

[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 The protection circuit shown in FIG. The scanning line 13 and the common wiring 29 are connected in the opposite directions to each other. In other words, between the scanning line 13 and the common wiring 29, the rectification direction is from the scanning line 13 to the common wiring 29. The transistors facing the wiring 29 and the transistors whose rectification direction is from the common wiring 29 to the scanning line 13 This is a configuration in which a resistor is 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 layer between the insulating layer and 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 the first terminal 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. In another configuration, a nonlinear element is added in parallel to form a protection circuit. For example, FIG. 3 shows a cross-sectional view of a scanning line 13 and a common line 29. The nonlinear elements 30a and 30b, and the nonlinear elements 31a and 31b This protection circuit is configured by connecting a first terminal (gate) to a common wiring 29. The first terminal (gate) of the two nonlinear elements (30b, 31b) is connected to the scanning line 13. A total of four nonlinear elements are used: two connected nonlinear elements (30a, 31a). In other words, a set of two nonlinear elements connected so that the rectification directions are opposite to each other is connected to a common wiring. 29 and the scanning line 13. In other words, Between them, there are two transistors whose rectification direction is from the scanning line 13 to the common wiring 29, and This is a configuration in which two transistors are connected from the common wiring 29 toward the scanning line 13. In this way, the common wiring 29 and the scanning line 13 are connected with four nonlinear elements, so that the scanning line 13 Not only when a surge voltage is applied, but also when the common wiring 29 is charged with static electricity, etc. However, this can prevent the electric charge from flowing directly into the scanning line 13. FIG. 9 shows an example of the arrangement of four nonlinear elements on a substrate together with an equivalent circuit diagram. The equivalent circuit diagram shown in FIG. 9(B) is equivalent to FIG. 3, and the circuit diagram shown in FIG. 9(B) is equivalent to FIG. Each nonlinear element corresponds to the nonlinear element shown in FIG. 40a corresponds to the nonlinear element 30b, and the nonlinear element 740b corresponds to the nonlinear element 31b. Nonlinear element 740c corresponds to nonlinear element 30a, and nonlinear element 740d corresponds to nonlinear element 31. 9 corresponds to the scanning line 13, and the common wiring 650 corresponds to the common wiring 651. This corresponds to the wiring 29. Therefore, the four nonlinear elements shown in FIG. One embodiment of the protection circuit formed in this manner is also one embodiment of the protection circuit shown in FIG.

[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. 8(A) shows an equivalent circuit diagram, and FIG. 8(B) shows an equivalent circuit diagram. , 730b, and 730a are connected as switching elements. By connecting in series, it is possible to distribute the instantaneous load applied to the nonlinear elements that make up the protection circuit. do.

[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. An example of the configuration of the protection circuit will be described with reference to FIG.

[0031] The nonlinear element 170a and the nonlinear element 170b are gate electrodes formed in the same layer as the scanning line 13. The gate electrode 111 and the gate electrode 16 are provided on the gate electrode 111 and the gate electrode 16. A gate insulating film 102 is formed on the first oxide semiconductor layer 101. A region overlapping with the channel formation region of the first oxide semiconductor layer 113 is formed. A channel protection layer 116 is formed, and the channel protection layer 116 and the first oxide semiconductor layer 113 The first wiring layer 117a and the second wiring layer 117b are disposed opposite each other on the gate electrode 111 with The nonlinear element 170a and the nonlinear element 170b are provided in the main portion. All of them have the same configuration.

[0032] In one embodiment of the present invention, the gate insulating film 102 is provided with a contact hole 128 through which the gate The scanning line 13 formed in the same layer as the gate electrode 111 and the third terminal (drain) of the nonlinear element 170a By directly connecting the conductor, not only is it possible to suppress the formation of an interface that accompanies the connection, The formation of contact holes required for connection can be reduced to one.

[0033] The first oxide semiconductor layer 113 is disposed under the first wiring layer 117a and the second wiring layer 117b facing each other. The gate electrode 111 is covered with a gate insulating film. The oxide semiconductor layer 113 is provided with a channel protection layer 116 which covers the region overlapping with the channel formation region. the lower surface of the gate insulating film 102 overlapping the gate electrode 111 and the second oxide semiconductor The first layer 114a and the second layer 114b are in contact with each other. The line layer 117a is a layer including the second oxide semiconductor layer 114a and the conductive layer 115a from the first oxide semiconductor layer 113 side. Similarly, the second wiring layer 117b is made of the first oxide semiconductor. The second oxide semiconductor layer 114b and the conductive layer 115b are laminated from the conductive layer 113 side. is.

[0034] The second oxide semiconductor layers (114a and 114b) are formed by stacking the first oxide semiconductor layer 113 and the conductive layer (1 115a and 115b), and the first oxide semiconductor layer 113 and the first oxide The second oxide semiconductor layer (114a and 114b) has a higher electrical conductivity than the oxide semiconductor layer 113. ) is in contact with each other, forming a junction between oxide semiconductor layers having different physical properties. By providing the nonlinear element 170a and the nonlinear element 170b with In other words, thermal stability is increased, and stable operation is possible. This improves the function of the protection circuit and stabilizes operation. This can improve the characteristics of the nonlinear elements 170a and 170b.

[0035] In this specification, the oxide semiconductor used for the first oxide semiconductor layer is InMO 3 (ZnO) m (m >0), and a nonlinear element and a thin film using the thin film as a semiconductor layer. A thin film transistor is fabricated. M is selected from Ga, Fe, Ni, Mn, and Co. It represents one or more metal elements. For example, M can be Ga, or The above metal elements other than Ga may be included, such as Ga and Ni or Ga and Fe. In the above oxide semiconductor, in addition to the metal element contained as M, Fe, Some of these contain Ni or other transition metal elements, or oxides of these transition metals. In the literature, this thin film is also referred to as an In-Ga-Zn-O non-single crystal film.

[0036] Inductively coupled plasma mass spectrometry (ICP-MS) Representative measurement examples using ED Plasma Mass Spectrometry are shown below. 1. Indium oxide (In 2 O 3 ) and gallium oxide (Ga 2 O 3 ) and zinc oxide (Z nO) composition ratio is 1:1:1 (=In 2 O 3 :Ga 2 O 3 ZnO) as the target ( In:Ga:Zn=1:1:0.5) was used, and the argon gas flow rate was set to 40 s The oxide semiconductor film obtained under condition 1 with ccm is InGa 0.95 Zinc0.41 O 3. 33 In addition, the argon gas flow rate in the sputtering method was 10 sccm and the oxygen flow rate was 5 sccm. The oxide semiconductor film obtained under condition 2 is InGa 0.94 Zinc 0.40 O 3.31 in be.

[0037] [Table 1]

[0038] The measurement method was Rutherford backscattering spectrometry (RBS). The results are shown in the figure. Shown in 2.

[0039] [Table 2]

[0040] The sample under condition 1 was measured by RBS analysis. As a result, the oxide semiconductor film was InGa 0.93 Zinc 0 .44 O 3.49 In addition, the RBS analysis of the sample under condition 2 showed that the oxide semiconductor The membrane is InGa 0.92 Zinc 0.45 O 3.86 It is.

[0041] The crystal structure of the In-Ga-Zn-O non-single crystal film is amorphous, as determined by X-ray diffraction (XRD). This was observed in the analysis of the measured samples. The In-Ga-Zn-O non-single crystal film was formed by sputtering and then heat-treated for 200 The treatment is carried out at ℃ to 500℃, typically 300 to 400℃, for 10 to 100 minutes. The electrical characteristics of the transistor are also such that the on-off ratio is 10 at a gate voltage of ±20V. 9 Above is the transfer Movement is 10cm 2 It is possible to create / V·S or higher.

[0042] The second oxide semiconductor layers (114a and 114b) have a higher Therefore, the nonlinear element 170a and the nonlinear element 170b illustrated in this embodiment have a high electrical conductivity. In the nonlinear element 170b, the second oxide semiconductor layers (114a and 114b) are The source and drain regions of a transistor function similarly. The second oxide semiconductor layer regions (114a and 114b) have n-type conductivity, The activation energy (ΔE) is 0.01 eV or more and 0.1 eV or less, and n + Also called the area The second oxide semiconductor layer is a non-single-crystal oxide semiconductor containing In, Ga, Zn, and O. If it is a layer, the nanocrystals may be contained within a non-single crystalline structure.

[0043] A channel protection layer 116 is formed in a region overlapping with a channel formation region of the first oxide semiconductor layer 113. Therefore, a region on the opposite side to the surface of the first oxide semiconductor layer that is in contact with the gate insulating film, The first wiring layer 117a and the second wiring layer 117 b can be formed.

[0044] The channel protection layer 116 is formed of an oxide such as silicon oxide or aluminum oxide. In addition, silicon nitride, aluminum nitride, or oxide can be deposited on silicon oxide or aluminum oxide. By stacking silicon nitride or aluminum oxynitride, the function as a protective film is improved. It is possible.

[0045] In any case, the channel protection layer 116 in contact with the first oxide semiconductor layer 113 is made of an oxide. As a result, oxygen is extracted from the first oxide semiconductor layer 113, and the first oxide semiconductor layer 113 changes to an oxygen-deficient type. In addition, the first oxide semiconductor layer 113 can be prevented from being directly connected to the insulating layer made of nitride. By adopting a structure in which the nitride is not in direct contact with the first oxide semiconductor layer 113, hydrogen in the nitride is diffused and the first oxide semiconductor layer 113 This can prevent the generation of defects caused by hydroxyl groups and the like.

[0046] In this manner, according to the present embodiment, a display having a protection circuit made of an oxide semiconductor is provided. The second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a region where the conductive layer and the first oxide semiconductor layer are bonded via the dielectric layer, stable operation is achieved. This makes it possible to improve the functionality of the protection circuit and stabilize operation. Also, the gate electrode can be contacted through a contact hole 128 provided in the gate insulating film 102. The scanning line 13 formed in the same layer as 111 and the third terminal (drain) of the nonlinear element 170a By directly connecting the two, it is possible to suppress the formation of an interface due to the connection to one, and also to This reduces the number of contact holes required for the protection circuit to one. This not only stabilizes the operation of the display, but also reduces the area occupied by the protection circuit. In particular, the number of nonlinear elements constituting the protection circuit has increased to three or four. The larger the thickness, the greater the effect of suppressing the formation of interfaces and contact holes associated with connection. In addition, by providing the channel protection layer 116, the back channel is not damaged. Therefore, the first wiring layer 117a and the second wiring layer 117b can be formed easily.

[0047] 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.

[0048] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0049] (Embodiment 2) In this embodiment mode, the manufacturing process of the protection circuit shown in FIG. The embodiment will be described with reference to Fig. 6 to Fig. 7. Fig. 6 to Fig. 7 are cut along the line Q1-Q2 in Fig. 4(A). 1 shows a cross-sectional view corresponding to

[0050] 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, the ratio of boric acid (B 2 O 3 ) than barium oxide (Ba 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. .

[0051] Next, the gate wiring including the gate electrode 111 and the scanning line 13, the capacitance wiring and the end of the terminal portion A conductive film that will become a substrate is formed on the entire surface of the substrate 100. The conductive film is made of aluminum (Al) or copper (C). It is desirable to form the electrode from a low-resistance conductive material such as aluminum, but aluminum alone has poor heat resistance. In addition, since there are problems such as being susceptible to corrosion, they are formed in combination with heat-resistant conductive materials. The conductive materials include titanium (Ti), tantalum (Ta), tungsten (W), molybdenum (Mo), and Mo, Cr, Nd, Sc or an alloy containing the above elements, or a nitride containing the above elements. Formed with things.

[0052] The conductive film that becomes the gate electrode 111 is formed to a thickness of 50 nm to 300 nm. By setting the thickness of the conductive film that will become the wiring layer including the electrode 111 to 300 nm or less, In addition, the semiconductor film and the wiring layer including the gate electrode 111 can be prevented from being broken. By making the thickness of the conductive film 150 nm or more, it is possible to reduce the resistance of the gate electrode. This allows for a large area.

[0053] In this embodiment, a film mainly made of aluminum and a titanium film are formed as a conductive film on the entire surface of the substrate 100. The above are laminated and formed into a film by a sputtering method.

[0054] Next, a resist mask formed using the first photomask in this embodiment is used. The unnecessary parts of the conductive film formed on the substrate are removed by etching to form wiring and electrodes (gates). At this time, at least the gate wiring including the gate electrode 111, the capacitance wiring, and the terminal are formed. The gate electrode 111 is also etched so that the end portion thereof is tapered. A cross-sectional view of the above is shown in FIG.

[0055] Next, the gate insulating film 102 is formed. is a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon nitride oxide film, an aluminum oxide film, Magnesium oxide film, aluminum nitride film, yttrium oxide film, hafnium oxide film, acid An example of this is a tantalum oxide film.

[0056] Here, the silicon oxynitride film is a film whose composition contains more oxygen than nitrogen. The concentration range is 55 to 65 atomic percent for oxygen, 1 to 20 atomic percent for nitrogen, and 25 to 40 atomic percent for silicon. 35 atomic % and hydrogen in the range of 0.1 to 10 atomic %. Silicon oxynitride A bare film is a film whose composition contains more nitrogen than oxygen, and the concentration range is Oxygen is 15-30 atomic %, nitrogen is 20-35 atomic %, Si is 25-35 atomic %, and hydrogen is This refers to a content in the range of 15 to 25 atomic %.

[0057] The gate insulating film may be a single layer, or may be formed by laminating two or three insulating films. For example, the gate insulating film in contact with the substrate may be formed using a silicon nitride film or a silicon oxynitride film. This increases the adhesion between the substrate and the gate insulating film, and when a glass substrate is used, It is possible to prevent impurities from the gate electrode from diffusing into the oxide semiconductor layer. This can prevent the wiring layer including the electrode 111 from being oxidized. In other words, this can prevent the film from peeling off. Furthermore, the electrical characteristics of the thin film transistor to be formed later can be improved.

[0058] The thickness of the gate insulating film 102 is set to 50 to 250 nm. If the thickness is 1 nm or more, it is possible to cover the irregularities of the wiring layer including the gate electrode 111, which is preferable. In this embodiment, the gate insulating film 102 is formed by plasma CVD or sputtering. A silicon oxide film having a thickness of 0 nm is formed.

[0059] Next, a resist mask formed using the second photomask in this embodiment mode is used. The gate insulating film 102 is etched to form a contact hole 128 reaching the scanning line 13. Form.

[0060] Next, a plasma treatment is performed on the gate insulating film 102 before the first oxide semiconductor film is formed. In this experiment, oxygen gas and argon gas were introduced to generate plasma and reverse sputtering was performed. The gate insulating layer is exposed to oxygen radicals or oxygen. Remove any debris that may be present.

[0061] The plasma treatment of the gate insulating film 102, the first oxide semiconductor film, and the channel protection layer The insulating film is formed by sputtering, by appropriately adjusting the gas introduced into the chamber or the target placed therein. By switching the temperature, continuous film formation can be achieved without exposure to the atmosphere. By forming the films continuously without exposing them to the air, it is possible to prevent the inclusion of impurities. In the case of continuous film formation, it is preferable to use a multi-chamber manufacturing apparatus.

[0062] In particular, the plasma treatment of the gate insulating film 102 in contact with the first oxide semiconductor film and the It is desirable to perform the deposition of the solid film continuously without exposing it to the air. The laminated interface is free from contamination by atmospheric components such as water vapor, impurities floating in the air, and dust. Since the nonlinear elements and the thin film transistors can be formed, the variations in the characteristics can be reduced.

[0063] In this specification, continuous film formation refers to a process in which a first process is performed by sputtering, followed by a second process by sputtering. During the series of processes up to the second processing step, the atmosphere in which the substrate is placed is air or the like. Always keep the equipment in a vacuum or inert gas atmosphere (nitrogen or rare earth) without contact with contaminated atmosphere. By performing continuous deposition, the surface is cleaned and Film formation can be performed while preventing moisture from adhering to the processing substrate. Plasma processing such as tantalum processing is also included in the continuous film formation.

[0064] Next, the first oxide semiconductor is formed on the plasma-treated gate insulating film 102 without exposing it to the atmosphere. The first oxide film is formed without exposing the plasma-treated gate insulating film 102 to the atmosphere. By forming the semiconductor film, dust is removed from the interface between the gate insulating film 102 and the first oxide semiconductor film. In addition, the first oxide semiconductor film is formed by The same chamber as that used for reverse sputtering may be used, or the chamber may be used without exposure to the atmosphere. If it is possible to form a film, it should be formed in a chamber different from the one used for the previous reverse sputtering. This is also fine.

[0065] Here, an oxide semiconductor target containing In, Ga, and Zn with a diameter of 8 inches (composition ratio) was used. As, In 2 O 3 :Ga 2 O 3 ZnO=1:1:1) was used to separate the substrate and the target. Distance between the two is 170 mm, pressure is 0.4 Pa, DC power is 0.5 kW, argon or The film is formed in an oxygen atmosphere. If a pulsed direct current (DC) power supply is used, dust can be reduced. The thickness of the first oxide semiconductor film is preferably 5 nm to 200 nm. In this embodiment, the first oxide semiconductor film has a thickness of 100 nm.

[0066] The first oxide semiconductor film has a lower electrical conductivity than the second oxide semiconductor film. For example, the second oxide semiconductor film is formed under different conditions from the conditions for forming the first oxide semiconductor film. The ratio of the oxygen gas flow rate to the argon gas flow rate in the deposition conditions of the first oxide semiconductor film is more important than the ratio of the oxygen gas flow rate to the argon gas flow rate. Specifically, the second oxide semiconductor film is formed under the following conditions: In a rare gas (argon, helium, etc.) atmosphere (or oxygen gas 10% or less, argon The first oxide semiconductor film is formed under an oxygen atmosphere (or oxygen gas 90%). The flow rate is equal to or greater than that of argon gas.

[0067] The first oxide semiconductor film is formed in an oxygen-rich atmosphere. The conductivity of the first oxide semiconductor can be made lower than that of the first oxide semiconductor in an atmosphere containing a large amount of oxygen. By forming a thin film, the off-current can be reduced, and the on-off ratio can be reduced. High-performance thin film transistors can be obtained.

[0068] Next, an insulating film to be a channel protection layer is formed on the first oxide semiconductor film. The first oxide semiconductor film is then deposited on the second oxide semiconductor film. The back channel, which is the area opposite to the surface that comes into contact with the air, is filled with atmospheric components such as water vapor and airborne particles. This allows the formation of a lamination interface that is free from contamination by floating impurity elements and dust, The variation in element characteristics can be reduced.

[0069] In this example, a silicon oxide (artificial quartz) target and a target for an oxide semiconductor film were prepared. Using a multi-chamber sputtering device, the first oxide semiconductor formed in the previous process was A silicon oxide film is formed as a channel protection layer without exposing the body film to the atmosphere.

[0070] Next, a resist mask formed using the third photomask in this embodiment is used. A silicon oxide film formed on the first oxide semiconductor film is selectively etched to form a channel protection film. A layer 116 is formed. A cross-sectional view at this stage is shown in FIG.

[0071] Next, a second oxide semiconductor film is formed on the channel protection layer 116 and the first oxide semiconductor film by sputtering. Here, an oxide semiconductor ternary layer containing In, Ga, and Zn with a diameter of 8 inches is formed. Get (composition ratio: In 2 O 3 :Ga 2 O 3 ZnO=1:1:1) was used as a substrate. The distance between the target and the sample was 170 mm, the pressure was 0.4 Pa, and the DC power supply was 0.5 kW. The deposition temperature is set to room temperature, and argon gas is introduced at a flow rate of 40 sccm to perform sputter deposition. As a result, a semiconductor containing In, Ga, Zn, and oxygen as components is formed as the second oxide semiconductor film. A film is formed. 2 O 3 :Ga 2 O 3 : The target is intended to be ZnO = 1:1:1 Even though it is widely used, the oxide film contains crystal grains of 1 nm to 10 nm in size immediately after deposition. Semiconductor films are often formed. The target composition ratio and film formation pressure (0.1 Pa to 2 .0Pa), power (250W~3000W: 8 inch diameter), temperature (room temperature~100℃), By appropriately adjusting the film formation conditions of reactive sputtering, the presence or absence of crystal grains, the density of crystal grains, and the direction of crystal grains can be controlled. It can be said that the diameter size can be adjusted in the range of 1 nm to 10 nm. The thickness is 5 nm to 20 nm. Of course, if the film contains crystal grains, the thickness of the crystal grains In this embodiment, the thickness of the second oxide semiconductor film is , 5 nm.

[0072] Next, a fourth photolithography step is performed to form a resist mask and a first oxide semiconductor The conductive film and the second oxide semiconductor film are etched. Here, ITO07N (Kanto Chemical Co., Ltd.) The unnecessary portions are removed by wet etching using a material other than SiO 2 , to form the first oxide semiconductor layer 11. 3 and the second oxide semiconductor layer 114. Note that the etching here is performed by wet etching. The method is not limited to etching, and dry etching may be used. As shown in C).

[0073] Next, a conductive film made of a metal material is formed on the second oxide semiconductor layer 114 and the gate insulating film 102. The conductive film 105 is formed by sputtering or vacuum deposition. The material of the conductive film 105 is Al, Cr, , Ta, Ti, Mo, W, or an alloy containing the above elements, or Examples of the thin film include an alloy film made by combining the above-mentioned elements.

[0074] In addition, if heat treatment at 200℃ to 600℃ is performed during the process, the material must be heat resistant to withstand this heat treatment. It is preferable to give the conductive film a conductive material with Al. Aluminum alone has poor heat resistance and is prone to corrosion. Due to problems, it is formed by combining with heat-resistant conductive material. Heat resistance combined with Al Conductive materials include titanium (Ti), tantalum (Ta), tungsten (W), and molybdenum (Mo). Mo (Mo), Chromium (Cr), Nd (Neodymium), Sc (Scandium) An element, an alloy containing the above elements, or a nitride containing the above elements It is formed by.

[0075] Here, as the conductive film 105, a Ti film and an aluminum containing Nd (Al-Nd) film are laminated, and further, a three-layer structure in which a Ti film is formed on the laminated films is formed. Also, the conductive film 105 may have a two-layer structure, and a titanium film may be laminated on an aluminum film. Further, the conductive film 105 may have a single-layer structure of an aluminum film containing silicon or a single-layer structure of a titanium film. A cross-sectional view at this stage is shown in FIG. 7(A).

[0076] Note that since the contact hole 128 is formed in the gate insulating film 102, the conductive film 105 that becomes the source electrode layer and the drain electrode layer during film formation is connected to the scanning line 13 through the contact hole 128.

[0077] Next, a fifth photolithography process is performed to form the resist mask 131, and unnecessary portions of the conductive film 105 are removed by etching to form the conductive layers 115a and 115b (see FIG. 7(B)). As the etching method at this time, wet etching or dry etching is used. Here, a mixed gas of SiCl and Cl 4 and BCl 2 is used as the reaction gas 3 and the conductive film in which the Al-Nd film and the Ti film are laminated is etched by dry etching to form the conductive layers 115a and 115b. A cross-sectional view at this stage is shown in FIG. 7(B).

[0078] Next, it is preferable to perform heat treatment at 200°C to 600°C, typically 300°C to 500°C. Here, it is placed in a furnace and heat-treated at 350°C for 1 hour in a nitrogen atmosphere or an air atmosphere. This heat treatment causes rearrangement at the atomic level in the In-Ga-Zn-O non-single crystal film. This heat treatment releases the distortion that inhibits carrier movement, The timing of the heat treatment is important because the oxide semiconductor There are no particular limitations on the method as long as it is performed after the film is formed, and it may be performed, for example, after the pixel electrode is formed. Thus, the nonlinear element 170a having the first oxide semiconductor layer 113 as a channel formation region can be fabricated. .

[0079] Next, an interlayer insulating film 107 is formed to cover the nonlinear element 170a. Silicon nitride film, silicon oxide film, silicon oxynitride film obtained by sputtering method, etc. Aluminum oxide film, tantalum oxide film, etc. can be used. The lithography process uses five photomasks to create a multi-nonlinear element. A protection circuit (having two nonlinear elements 170a and 170b in this embodiment) The cross-sectional view at this stage is shown in Figure 7(C).

[0080] Following the formation of the protection circuit, the display pixel is formed integrally with the nonlinear element in the same process. A pixel electrode is formed on the thin film transistor in the pixel portion. First, a sixth resist mask (not shown) is used to form a second resist mask (not shown). The contact hole that reaches the drain electrode layer of the thin film transistor in the pixel part that is not It is formed on the velum 107.

[0081] Next, the resist mask is removed, and then a transparent conductive film is formed. Indium oxide (In 2 O 3) and indium tin oxide alloy (In 2 O 3 - SnO 2 The ITO film is formed by sputtering or vacuum deposition. Etching of such materials is done with a hydrochloric acid based solution. However, etching of ITO in particular Residues are easily generated, so indium oxide zinc oxide alloy is used to improve etching processability. Gold 2 O 3 -ZnO) may also be used.

[0082] Next, a seventh photolithography step is performed to form a resist mask and perform etching. The unnecessary part of the transparent conductive film is removed to form the pixel electrode. The insulating film 102 and the interlayer insulating film 107 are dielectrics, and the capacitance wiring and the pixel electrode form a storage capacitance. In addition, a transparent conductive film is left on the terminal area to form electrodes or wiring for connection with the FPC. Furthermore, a terminal electrode for connection that functions as an input terminal of the source wiring is formed.

[0083] In this way, pixel voltages are applied to the plurality of thin film transistors that are integrally formed in the same process as the nonlinear element. When the electrode is formed, the pixel part having the n-channel TFT and the protection circuit are simultaneously fabricated. The second oxide semiconductor layer has a higher electrical conductivity than the first oxide semiconductor layer. By providing a junction area, it is possible to achieve stable operation. The function of the gate insulating film 102 can be improved to stabilize the operation. Through the tact hole 128, the scanning line 13 formed in the same layer as the gate electrode 111 and the non- By directly connecting the third terminal (drain) of the linear element 170a, the shape of the interface due to the connection Not only can the formation of the contact holes for connection be suppressed to one, but also the formation of the contact holes for connection can be suppressed to one. As a result, not only can the function of the protection circuit be improved and operation can be stabilized, but also the protection The area occupied by the protection circuit can be reduced, and the display device can be made smaller. By following the steps shown in the embodiment, the function of the protection circuit can be improved and the operation can be stabilized. In addition, it is also used for active matrix display devices equipped with protection circuits that occupy a small area. In addition, by providing a channel protection layer 116, damage to the back channel can be prevented. The first wiring layer 117a and the second wiring layer 117b can be formed without giving a gap.

[0084] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0085] (Embodiment 3) In this embodiment, a display device to which one embodiment of the present invention is applied has a protection circuit and a display device having a protection circuit and a display device formed on the same substrate. 1 shows an example of electronic paper having thin film transistors arranged in pixel portions.

[0086] 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 semiconductor device is The nonlinear element shown in Fig. 2 can be fabricated in the same manner as the nonlinear element shown in Fig. 3. The semiconductor is an oxide semiconductor containing In, Ga, and Zn. The thin-film transistor has excellent electrical properties and is made of a thin film of ZnO.

[0087] The electronic paper in Figure 10 is an example of a display device that uses the twisting ball display method. The spherical display method uses black and white spherical particles as the display element and an electrode layer. 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.

[0088] A thin film transistor 581 formed on a substrate 580 includes a gate insulating layer 583 and an insulating layer 58 5, an opening is formed in the insulating layer 585. The source or drain electrode layer is electrically connected to the first electrode layer 587 through an insulating film 584. A black area is formed between the first electrode layer 587 and the second electrode layer 588 formed on the substrate 596. 590a and white area 590b, and a cavity 594 filled with liquid therearound. The spherical particles 589 are surrounded by a filler 595 such as a resin. It is filled (see Figure 10).

[0089] 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.

[0090] The protection circuit mounted on the electronic paper produced by the above process is a contact for connection. The area occupied by the oxide semiconductor layer is reduced by reducing the number of holes, and the electrical conductivity is higher than that of the first oxide semiconductor layer. A second oxide semiconductor layer having a high efficiency is provided between the first oxide semiconductor layer and the wiring layer. Therefore, the power supply of the present embodiment equipped with such a protection circuit has a high resistance and a stable operation. The child paper is highly reliable.

[0091] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0092] (Embodiment 4) In this embodiment, in a display device according to one embodiment of the present invention, at least An example of manufacturing a protection circuit, a part of a driver circuit, and a thin film transistor arranged in a pixel area The following will explain this with reference to FIGS. 11 to 16.

[0093] The thin film transistor disposed in the pixel portion on the same substrate as the protection circuit is the nonlinear transistor shown in the embodiment 2. The thin film transistor formed is an n-channel TFT. Therefore, some of the driving circuits that can be configured with n-channel TFTs are displayed. It is formed on the same substrate as the thin film transistor of the elemental portion.

[0094] FIG. 11 is a block diagram showing an example of an active matrix type liquid crystal display device according to one embodiment of the present invention. The display device shown in FIG. 11A has a pixel structure including a display element on a substrate 5300. A pixel portion 5301 having a plurality of pixels, a scanning line driver circuit 5302 for selecting each pixel, and a signal line driver circuit 5303 for controlling input of a video signal to the pixel.

[0095] 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.

[0096] In addition, a thin film transistor that can be formed in the same manner as the nonlinear element shown in the second embodiment is FIG. 1 shows a signal line driver circuit configured with an n-channel TFT. This will be explained using 12.

[0097] 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.

[0098] 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

[0099] The first wiring 5611, the second wiring 5612, and the third wiring 5613 are each connected to a signal line. The number is entered.

[0100] 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.

[0101] 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. shows a timing chart in the case. Further, the selection period of the scanning line Gi in the i-th row is divided into a first sub-selection period T1, a second sub-selection period T2, and a third sub-selection period T3. Further, the signal line driving circuit in FIG. 12 operates in the same manner as in FIG. 13 even when scanning lines of other rows are selected.

[0102] Note that the timing chart in FIG. 13 shows the case where the wiring 5621_J in the J-th column is connected to the signal lines Sj-1, Sj, and Sj+1 via the first thin film transistor 5603a, the second thin film transistor 5603b, and the third thin film transistor 5603c.

[0103] Note that the timing chart in FIG. 13 shows the timing when the scanning line Gi in the i-th row is selected, the on / off timing 5703a of the first thin film transistor 5603a, the on / off timing 5703b of the second thin film transistor 5603b, the on / off timing 5703c of the third thin film transistor 5603c, and the signal 5721_J input to the wiring 5621_J in the J-th column.

[0104] Note that different video signals are input to the wirings 5621_1 to 5621_M during the first sub-selection period T1, the second sub-selection period T2, and the third sub-selection period T3, respectively. For example, the video signal input to the wiring 5621_J during the first sub-selection period T1 is input to the signal line Sj-1, the video signal input to the wiring 5621_J during the second sub-selection period T2 is input to the signal line Sj, and the video signal input to the wiring 5621_J during the third sub-selection period T3 is input to the signal line Sj+1. Further, during the first sub-selection period ​​​​​​​​​​​​​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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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 selection period before the sub selection period, the signal lines can be precharged. This allows high-speed writing of video signals to the pixels. In this embodiment, the same reference numerals are used for the same parts as those in FIG. 13, and the same parts or similar functions are shown. A detailed description of the portion having the symbol will be omitted.

[0111] 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.

[0112] 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.

[0113] The circuit configuration of the shift register is shown in Figure 15. The shift register shown in Figure 15 is a flip-flop. It is composed of multiple flip-flops 5701_1 to 5701_n. A first clock signal, a second clock signal, a start pulse signal, and a reset signal are input. It works as it is.

[0114] 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 .

[0115] 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.

[0116] 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 .

[0117] 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.

[0118] 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.

[0119] Next, the connection configuration of the flip-flop shown in FIG. 16 will be described below.

[0120] 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 .

[0121] 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 .

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] In addition, the signal line driver circuit and the scanning line driver circuit may be formed in the same manner as the nonlinear element shown in the second embodiment. It is also possible to fabricate the device using only n-channel TFTs that can be formed by the above method. The n-channel TFT, which can be formed in a similar manner to the nonlinear element shown in Form 2, is a transistor. Since the mobility of the star is large, it is possible to increase the driving frequency of the driving circuit. For example, In addition to the nonlinear element shown in the second embodiment, an n-channel TFT that can be formed in the same manner is used. The scanning line driver circuit can be operated at high speed, so the frame frequency can be increased. It is also possible to insert a black screen.

[0130] 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 multiple If signals are output to the same scanning line by the scanning line driving circuit, it is advantageous for making the display device larger. do.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] In the light-emitting display device shown in FIG. 11B, two switching TFTs are provided for one pixel. When the first scanning line, which is the gate wiring of one of the switching TFTs, is used as the first scanning line, The signal to be outputted is generated by the first scanning line driver circuit 5402 and is applied to the gate of the other switching TFT. A signal input to the second scanning line, which is a 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 Both of these may be generated by a single scanning line driving circuit. The number of switching TFTs in a pixel determines the operation of the switching element. A plurality of scanning lines may be used for each pixel. The signals input to the scanning line driver circuit may all be generated by one scanning line driver circuit, or may be generated by a plurality of scanning line drivers. It may be generated by an automatic circuit.

[0136] 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 similarly configured together with the nonlinear element shown in the second embodiment. It is also possible to fabricate the device using only n-channel TFTs that can be formed by the method described above.

[0137] 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.

[0138] 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. 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

[0139] 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. Electrophoretic displays do not require polarizing plates or opposing substrates, which are necessary for display devices, and are half the thickness and weight. Reduce.

[0140] 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.

[0141] 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. If an electric field is applied to the cell, a display can be performed. For example, the nonlinear element shown in the second embodiment The active matrix obtained by thin film transistors can be formed in a similar manner with the A substrate can be used.

[0142] 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.

[0143] The protective circuit mounted on the display device manufactured by the above process is a contact for connection. The holes are reduced, reducing the area occupied, and the electrical conductivity is higher than that of the first oxide semiconductor layer. A highly functional second oxide semiconductor layer is provided between the first oxide semiconductor layer and the wiring layer. Therefore, the display device of this embodiment equipped with such a protection circuit is stable in operation. The installation is highly reliable.

[0144] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0145] (Embodiment 5) In one embodiment of the present invention, a thin film transistor is fabricated together with the nonlinear element, and the thin film transistor A semiconductor device having a display function (also called a display device) is formed by using a transistor in a pixel portion and further in a driver circuit. In one embodiment of the present invention, a nonlinear element and a thin film transistor can be fabricated. The driver circuit is formed integrally on the same substrate as the pixel section, and the system An on-panel can be formed.

[0146] 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 applied.

[0147] 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.

[0148] 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.

[0149] In this embodiment, the appearance and cross section of a liquid crystal display panel according to one embodiment of the present invention will be described. The following description will be given with reference to FIG. 17. FIG. 17(A1) and (A2) show the first substrate 4 as well as the nonlinear element. The electrical conductivity of the semiconductor layer is determined by the oxide semiconductor layer containing In, Ga, and Zn formed on the substrate. The thin film transistors 4010 and 4011 having high characteristics and the liquid crystal element 4013 are disposed on the second substrate. 17(a) is a top view of the panel sealed with a sealant 4005 between the panel 4006 and the panel 4007. 17B) corresponds to a cross-sectional view taken along line MN in FIG. 17(A1)(A2).

[0150] 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 made up of a first substrate 4001, a sealant 4005, and a second substrate 4006. The liquid crystal layer 4008 is sealed together with the first substrate 4001. In a region different from the region surrounded by the material 4005, a single crystal is formed on a separately prepared substrate. A signal line driver circuit 4003 formed of a semiconductor film or a polycrystalline semiconductor film is mounted.

[0151] 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.

[0152] 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.

[0153] The thin film transistors 4010 and 4011 are made of an oxide semiconductor containing In, Ga, and Zn. This corresponds to a thin-film transistor with high electrical characteristics used in the conductor layer, and is a nonlinear element shown in the second embodiment. A thin film transistor that can be formed in a similar manner together with the semiconductor device can be applied. In this embodiment, the thin film transistors 4010 and 4011 are n-channel thin film transistors. do.

[0154] 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 .

[0155] 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, polyester film Alternatively, acrylic resin film can be used. Aluminum foil can also be used as a PVF film. A sheet having a structure sandwiched between films or polyester films can also be used.

[0156] 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.

[0157] 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, a liquid crystal composition containing 5% by weight or more of a chiral agent is used for the liquid crystal layer 4008. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a response speed of 10 μs to It is short at 100μs, has optical isotropy so no alignment treatment is required, and has small viewing angle dependency. stomach.

[0158] 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.

[0159] 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.

[0160] 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 are used. A thin-film transistor that can be formed in a similar manner is formed by forming an insulating layer that functions as a protective film or a planarizing insulating film. The protective film is covered with insulating layers (insulating layer 4020 and insulating layer 4021). It is designed to prevent the intrusion of contaminating impurities such as organic matter, metals, and water vapor suspended in the air. A dense film is preferable. The protective film is a silicon oxide film, a silicon nitride film, a silicon oxynitride film, etc., which are formed by sputtering. Silicon film, silicon oxynitride film, aluminum oxide film, aluminum nitride film, aluminum oxynitride film The insulating film 11 may be formed of a single layer or a multilayer of an aluminum oxide film or an aluminum nitride film. Here, an example of forming the protective film by sputtering will be shown, but there is no particular limitation and the film may be formed by various methods. good.

[0161] 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.

[0162] In addition, an insulating layer is formed as the second layer of the protective film. A silicon nitride film is formed by sputtering. Mobile ions such as thorium penetrate into the semiconductor region and change the electrical properties of the TFT. can be suppressed.

[0163] After forming the protective film, the oxide semiconductor layer was annealed (at 300°C to 400°C). This is also fine.

[0164] 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.

[0165] 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.

[0166] 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, In the step of annealing the oxide semiconductor layer, annealing (at 300° C. to 400° C.) may be performed at the same time. The insulating layer 4021 is baked in the same process as the oxide semiconductor layer is annealed, so that the semiconductor layer is efficiently baked. It is now possible to create a body device.

[0167] 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.

[0168] 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.

[0169] 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.

[0170] A signal line driver circuit 4003 and a scanning line driver circuit 4004 or a pixel section 4 Various signals and potentials are applied to 002 via FPC4018.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] The protection circuit mounted on the LCD panel manufactured by the above process is a contact for connection. The number of holes is reduced, reducing the area occupied, and the electrical conductivity is higher than that of the first oxide semiconductor layer. The second oxide semiconductor layer, which has a high resistance, is provided between the first oxide semiconductor layer and the wiring layer. Therefore, the liquid crystal display of the present embodiment having such a protection circuit has a high resistance and a stable operation. The panels are highly reliable.

[0178] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0179] (Embodiment 6) In one embodiment of the present invention, a thin film transistor is fabricated together with the nonlinear element, and the thin film transistor A semiconductor device having a display function (also called a display device) is formed by using a transistor in a pixel portion and further in a driver circuit. (u) can be produced.

[0180] 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 here. The light-emitting element that utilizes electroluminescence is an organic compound that is used as a light-emitting material. Generally, the former are organic EL elements and the latter are inorganic compounds. These are called electroluminescent devices.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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 embodiment can be formed by a similar method to that of the oxide semiconductor layer. An example in which two n-channel transistors are used in the filter formation region in one pixel is shown.

[0185] 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 .

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] 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.

[0192] 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 used in the semiconductor device, TFTs 7001, 7011, and 7021, are A thin film transistor that can be formed in a similar manner to the nonlinear element shown in the second embodiment, A thin-film transistor with excellent electrical characteristics using an oxide semiconductor containing n, gallium, and zinc for the semiconductor layer. It is Sta.

[0193] 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. Top emission, bottom emission, and side emission. There is a light-emitting element having a dual emission structure in which light is emitted from the side of the substrate. The present invention can be applied to any light emitting element with any emission structure.

[0194] A light emitting element having a top emission structure will be described with reference to FIG.

[0195] In FIG. 20A, a TFT 7001 which is a driving TFT is an n-type TFT, and a light emitting element 7002 emits light. FIG. 20(A) shows a cross-sectional view of a pixel when the light incident on the pixel exits the anode 7005 side. A cathode 7003 of a light emitting element 7002 and a TFT 7001 which is a driving TFT are electrically connected. A light-emitting layer 7004 and an anode 7005 are laminated in this order on a cathode 7003. 7003 uses various materials as long as they have a small work function and are conductive films that reflect light. For example, Ca, Al, MgAg, AlLi, etc. are preferable. 004 may be composed of a single layer or may be composed of multiple layers stacked together. In the case where the cathode 7003 is composed of a plurality of layers, an electron injection layer, an electron transport layer, and a The light-transmitting layer, the light-emitting layer, the hole-transporting layer, and the hole-injecting 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 zinc containing tungsten oxide Lead 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 are added. Alternatively, a light-transmitting conductive film such as doped indium tin oxide may be used.

[0196] 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.

[0197] Next, a light emitting element having a bottom emission structure will be described with reference to FIG. When 011 is an n-type light emitting element and light emitted from the light emitting element 7012 is emitted to the cathode 7013 side, FIG. 20B shows a cross-sectional view of a pixel. A cathode 7013 of a light-emitting element 7012 is formed on a light-transmitting conductive film 7017. A light-emitting layer 7014 and an anode 7015 are laminated in this order on the cathode 7013. When the anode 15 has a light-transmitting property, a shielding layer for reflecting or blocking light is provided so as to cover the anode. The cathode 7013 may have a film 7016 formed thereon, as in the case of FIG. Various conductive materials with small thermal coefficients can be used. However, the thickness of the material should be The thickness is set to a level that allows light to pass through (preferably, about 5 nm to 30 nm). For example, a 20 nm film An aluminum film having a thickness of 700 nm can be used as the cathode 7013. 014 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, but as shown in FIG. As in the case of 20(A), the insulating film 20 can be formed using a conductive material having light-transmitting properties. The shielding film 7016 may be made of, for example, a metal that reflects light, but is not limited to a metal film. For example, a resin containing a black pigment may be used.

[0198] 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.

[0199] 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.

[0200] 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.

[0201] 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.

[0202] 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.

[0203] 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.

[0204] Next, the appearance and cross section of a light-emitting display panel (also referred to as a light-emitting panel) according to one embodiment of the present invention will be described. FIG. 21A shows a nonlinear element according to one embodiment of the present invention. A thin-film transistor with excellent electrical properties is fabricated using an oxide semiconductor containing In, Ga, and Zn in the semiconductor layer. The upper surface of the panel is formed by sealing the transistor and the light emitting element with a sealing material between the second substrate and the panel. 21(B) corresponds to a cross-sectional view taken along line HI in FIG. 21(A).

[0205] 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.

[0206] A pixel portion 4502, a signal line driver circuit 4503a, and a fourth 503b and the scanning line driver circuits 4504a 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 signal 45, a thin film transistor 4509 included in a line driver circuit 4503a is illustrated.

[0207] The thin film transistors 4509 and 4510 are made of an oxide semiconductor containing In, Ga, and Zn. This corresponds to a thin-film transistor with high electrical characteristics used in the conductor layer, and is a nonlinear element shown in the second embodiment. A thin film transistor that can be formed in a similar manner together with the semiconductor device can be applied. In this embodiment, the thin film transistors 4509 and 4510 are n-channel thin film transistors. do.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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.

[0214] 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.

[0215] The second substrate located in the direction in which light is extracted from the light emitting element 4511 must be transparent. In that case, use a glass plate, a plastic plate, a polyester film or an acrylic plate. A light-transmitting material such as a film is used.

[0216] 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. The substance was used.

[0217] 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.

[0218] 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.

[0219] The protection circuit mounted on the light-emitting display device (display panel) manufactured by the above process is The contact holes for the first oxide semiconductor layer are reduced to reduce the occupied area. A second oxide semiconductor layer having a higher electrical conductivity than the first oxide semiconductor layer is provided between the first oxide semiconductor layer and the wiring layer. This protection circuit is highly functional and stable in operation. The light emitting display device (display panel) according to the embodiment has high reliability.

[0220] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0221] (Embodiment 7) 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] The protection circuit mounted on the display device of the present embodiment reduces the number of contact holes for connection. The area occupied by the second oxide semiconductor layer is reduced by 100% compared to the first oxide semiconductor layer. The oxide semiconductor layer is placed between the first oxide semiconductor layer and the wiring layer, providing high functionality and stable operation. The display device of this embodiment, which is equipped with such a protection circuit, has high reliability.

[0229] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is.

[0230] (Embodiment 8) 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.

[0231] 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.

[0232] 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.

[0233] 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).

[0234] 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.

[0235] 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 .

[0236] 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.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] 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.

[0241] 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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.

[0246] 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.

[0247] The protection circuit mounted on the electronic device of this embodiment reduces the number of contact holes for connection. The area occupied by the second oxide semiconductor layer is reduced by 100% compared to the first oxide semiconductor layer. The oxide semiconductor layer is placed between the first oxide semiconductor layer and the wiring layer, providing high functionality and stable operation. The electronic device of this embodiment incorporating such a protection circuit has high reliability.

[0248] This embodiment mode can be implemented in appropriate combination with the configurations described in other embodiments. It is. [Explanation of symbols]

[0249] 10 Substrate 11 Scan line input terminal 12 Signal line input terminal 13 Scan Lines 14 Signal Line 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 100 Substrates 102 Gate insulating film 105 Conductive film 107 Interlayer insulating film 111 Gate electrode 113 Oxide semiconductor layer 114 Oxide semiconductor layer 114a Oxide semiconductor layer 114b Oxide semiconductor layer 115a conductive layer 115b Conductive layer 116 Channel Protection Layer 117a wiring layer 117b Wiring layer 128 Contact Hole 131 Resist mask 170a Nonlinear element 170b Nonlinear element 580 Substrate 581 Thin film transistor 583 Gate insulating layer 584 Insulating layer 585 Insulating layer 587 Electrode layer 588 Electrode layer 589 Spherical particle 590a Black region 590b White region 594 Cavity 595 Filling material 596 Substrate 650 Common wiring 651 Scanning line 730a Nonlinear element 730b Nonlinear element 730c Nonlinear element 740a Nonlinear element 740b Nonlinear element 740c Nonlinear element 740d Nonlinear element 1000 Mobile phone 1001 Housing 1002 Display unit 1003 Operation button 1004 External connection port 1005 Speaker 1006 Microphone 2600 TFT substrate 2601 Opposite substrate 2602 Sealing material 2603 Pixel section 2604 Display element 2605 Coloring 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-vehicle advertisement 2700 E-book 2701 Case 2703 Case 2705 ​​Display section 2707 Display section 2711 Shaft 2721 Power supply 2723 Operation key 2725 Speaker 4001 Substrate 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 4501 Board 4502 Pixel section 4503a Signal line driver circuit 4504a Scanning 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 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 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 Input means (operation keys) 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 liquid crystal display device having a liquid crystal element, a first conductive layer in contact with a top surface of the substrate; a second conductive layer in contact with the upper surface of the substrate; a first insulating layer over the first conductive layer and over the second conductive layer; a first oxide semiconductor layer above the first insulating layer; a second oxide semiconductor layer above the first insulating layer; a third conductive layer above the first oxide semiconductor layer and above the second oxide semiconductor layer; a fourth conductive layer above the first oxide semiconductor layer and above the second oxide semiconductor layer, the first conductive layer has a region that becomes a gate electrode of a first transistor; the second conductive layer has a region that becomes a gate electrode of a second transistor; the first oxide semiconductor layer has a channel formation region of the first transistor, the second oxide semiconductor layer has a channel formation region of the second transistor, the third conductive layer has a region that becomes one of a source electrode and a drain electrode of the first transistor, the third conductive layer has a region that becomes one of a source electrode and a drain electrode of the second transistor, the third conductive layer is directly connected to the first conductive layer; the fourth conductive layer has a region that becomes the other of the source electrode and the drain electrode of the first transistor, the fourth conductive layer has a region that becomes the other of the source electrode and the drain electrode of the second transistor, the fourth conductive layer is directly connected to the second conductive layer; In a plan view, the fourth conductive layer has a third region arranged along a first direction, the first transistor and the second transistor are arranged on the same side with respect to the third region of the fourth conductive layer in a plan view; In a plan view, the first conductive layer has a first region that intersects with the third region of the fourth conductive layer, and a second region that is arranged along the first direction in which the fourth conductive layer extends, the first conductive layer is directly connected to the third conductive layer in the second region; a third oxide semiconductor layer is provided above the first oxide semiconductor layer and in contact with the third conductive layer; a fourth oxide semiconductor layer above the second oxide semiconductor layer and in contact with the third conductive layer;

2. In claim 1, The first oxide semiconductor layer, the second oxide semiconductor layer, the third oxide semiconductor layer, and the fourth oxide semiconductor layer each contain In, Ga, and Zn.

Images