Semiconductor device

Abstract

To provide a semiconductor device having a high aperture ratio and including a capacitor with an increased charge capacitance, and provide a semiconductor device with a narrower frame.SOLUTION: A semiconductor device includes: a transistor on a substrate; a first conductive film formed on a surface on which a gate electrode of the transistor is provided; a second conductive film formed on a surface on which a pair of electrodes of the transistor is provided; and a first light-transmitting conductive film electrically connected to the first conductive film and the second conductive film. The second conductive film is provided to overlap the first conductive film via a gate insulating film of the transistor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an article, a method, or a manufacturing method. The present invention relates to a method, manufacture, or composition of matter. The present invention relates to, for example, a semiconductor device, a display device, a light-emitting device, a power storage device, and a driving method thereof. In particular, the present invention relates to a semiconductor device having an oxide semiconductor, The present invention relates to a semiconductor device, a display device, or a light-emitting device. The present invention relates to a semiconductor device having a stator and a method for manufacturing the same. [Background technology]

[0002] It is used in many flat panel displays, such as liquid crystal displays and light-emitting displays. The transistors used are made of amorphous silicon and single crystal silicon formed on a glass substrate. The silicon semiconductor is made of silicon semiconductor such as polycrystalline silicon or polysilicon. Transistors using semiconductors are also used in integrated circuits (ICs).

[0003] In recent years, metal oxides that exhibit semiconducting properties have been used in transistors instead of silicon semiconductors. In this specification, the term "oxide" refers to a metal oxide that exhibits semiconductor properties. Let us call it a semiconductor.

[0004] For example, a transistor using zinc oxide or an In-Ga-Zn oxide as an oxide semiconductor may be used. A transistor is manufactured and used as a switching element for pixels of a display device. Techniques have been disclosed (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [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]

[0006] The capacitance element has a pair of electrodes and a dielectric film between them. The other electrode is a gate electrode, a source electrode, a drain electrode, or the like that constitutes a transistor. In many cases, the light-shielding conductive film is used.

[0007] In addition, in a liquid crystal display device, the larger the capacitance value of the capacitance element, the more In the liquid crystal display device, the period during which the alignment of the liquid crystal molecules in the liquid crystal element can be kept constant can be extended. When displaying a still image, the fact that the period can be extended is a This reduces the number of times, which is expected to reduce power consumption.

[0008] In order to increase the charge capacity of the capacitance element, the area occupied by the capacitance element is increased. However, there is a way to increase the area where the pair of electrodes overlap. In a display device, a light-shielding conductive film is used to increase the area where a pair of electrodes overlap. If the area of ​​the conductive film is increased, the aperture ratio of the pixel is reduced, and the display quality of the image is degraded. Such a problem is particularly noticeable in a high-resolution liquid crystal display device.

[0009] There is also a demand for reducing the area of ​​the display device other than the display region (narrowing the frame).

[0010] In view of the above, one embodiment of the present invention provides a capacitance-reducing film having a high aperture ratio and capable of increasing a charge capacity. Another object of the present invention is to provide a semiconductor device or the like having a quantum dot. Another object of the present invention is to provide a semiconductor device in which display defects are reduced. It is an object of the present invention to provide a semiconductor device that achieves the above.

[0011] The description of these problems does not preclude the existence of other problems. It is not necessary for one embodiment to solve all of these problems. The subject matter will be self-evident from the description, drawings, claims, etc. Other issues can be extracted from the drawings, claims, etc. [Means for solving the problem]

[0012] One aspect of the present invention is a transistor on a substrate and a gate electrode of the transistor on the same surface. A first conductive film is formed on the same surface as the pair of electrodes of the transistor. a first conductive film electrically connected to the first conductive film and the second conductive film; and a second conductive film, the second conductive film being connected to the first conductive film via a gate insulating film of a transistor. The semiconductor device is characterized by being overlapped.

[0013] In the above structure, the second light-transmitting conductive film over the substrate and the transistor are an oxide insulating film having an opening over the second light-transmitting conductive film; a nitride insulating film on the insulating film and in contact with the second light-transmitting conductive film in the opening; a third light-transmitting layer connected to the transistor and having a recess in the opening; and a conductive film.

[0014] A transistor is made up of a gate electrode formed on a substrate and a gate An insulating film, an oxide semiconductor film in contact with the gate insulating film, and a pair of conductive films in contact with the oxide semiconductor film. The second light-transmitting conductive film is in contact with the gate insulating film.

[0015] In addition, the oxide semiconductor film is formed on the same surface as the second light-transmitting conductive film.

[0016] The second light-transmitting conductive film and the oxide semiconductor film are formed of In, Ga, or Zn. Includes. Effect of the Invention

[0017] According to one embodiment of the present invention, a capacitance element having a high aperture ratio and capable of increasing a charge capacity is provided. In addition, according to one embodiment of the present invention, a semiconductor device having a display defect can be manufactured. In addition, according to one embodiment of the present invention, a semiconductor device having a narrow frame can be manufactured. It is possible to manufacture a semiconductor device that achieves high-speed operation. [Brief description of the drawings]

[0018] [Figure 1] 1A and 1B are a block diagram and a circuit diagram illustrating one embodiment of a semiconductor device. [Diagram 2] FIG. 1 is a top view illustrating one embodiment of a semiconductor device. [Diagram 3] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 4] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Diagram 5] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 6] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 7]1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 8] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 9] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 10] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 11] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 12] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 13] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 14] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 15] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Figure 16] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 17] 1A to 1C are cross-sectional views illustrating one embodiment of a method for manufacturing a semiconductor device. [Figure 18] 1 is a cross-sectional view illustrating one embodiment of a transistor. [Figure 19] 1 is a cross-sectional view illustrating one embodiment of a transistor. [Figure 20] 1 is a cross-sectional view illustrating one embodiment of a transistor. [Figure 21] 1 is a cross-sectional view illustrating one embodiment of a transistor. [Figure 22] 1 is a cross-sectional view illustrating one embodiment of a transistor. [Figure 23] 1 shows ultramicroelectron beam diffraction patterns of oxide semiconductors. [Figure 24] 1A to 1C are diagrams illustrating electronic devices using a semiconductor device which is one embodiment of the present invention. [Diagram 25] 1A to 1C are diagrams illustrating electronic devices using a semiconductor device which is one embodiment of the present invention. [Figure 26] FIG. 4 is a cross-sectional view of a liquid crystal display device according to a comparative example. [Figure 27] FIG. 11 is a layout diagram of the periphery of an opening in a liquid crystal display device of a comparative example. [Figure 28]FIG. 13 is a layout diagram of a liquid crystal display device according to a comparative example. [Figure 29] FIG. 2 is a diagram illustrating an overall configuration of a gate driver circuit. [Diagram 30] FIG. 2 is a diagram for explaining a shift register unit. [Diagram 31] FIG. 2 is a diagram for explaining a shift register unit which is a dummy stage. [Diagram 32] FIG. 1 is a diagram for explaining a demultiplexer. [Diagram 33] FIG. 1 is a diagram for explaining a demultiplexer. [Diagram 34] FIG. [Diagram 35] FIG. 13 is a diagram for explaining another shift register unit. [Diagram 36] FIG. 13 is a diagram for explaining a shift register unit which is another dummy stage. [Figure 37] FIG. 13 is a diagram for explaining another buffer. [Figure 38] FIG. [Figure 39] 4 is a timing chart of a shift register unit. [Diagram 40] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Diagram 41] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Diagram 42] 1 is a cross-sectional view illustrating one embodiment of a semiconductor device. [Diagram 43] FIG. 4 is a layout diagram of a drive circuit section. [Diagram 44] FIG. 4 is a layout diagram of a drive circuit section. [Diagram 45] 1A to 1C are diagrams illustrating cross-sectional TEM images of a liquid crystal display device. [Diagram 46] 1A to 1C are diagrams illustrating characteristics of a transistor. [Figure 47] 1A to 1C are diagrams illustrating characteristics of a transistor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description, and the embodiments and aspects of the present invention may be modified without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that various modifications may be made to the embodiments and details of the present invention. However, the present invention should not be construed as being limited to the description of the following embodiments and examples. In the following embodiments and examples, the same parts or parts having similar functions are In the case of parts, the same reference numerals or the same hatch patterns are used in common among different drawings, and the repetition The explanation of the repetition will be omitted.

[0020] In each figure described in this specification, the size, thickness, or area of ​​each component is indicated by the following formula: The figures may be exaggerated for clarity and are not necessarily limited to scale. stomach.

[0021] In addition, the terms "first," "second," "third," etc., used in this specification are used interchangeably to avoid confusion of components. The number is added for convenience and is not intended to be a numerical limit. The terms can be replaced with "second" or "third" as appropriate for explanation.

[0022] The function of the "source" and "drain" is to change the direction of the current during circuit operation. For this reason, in this specification, the terms "sauce" and "dressing" are used interchangeably. The terms "in" and "in" can be used interchangeably.

[0023] Voltage is the potential difference between two points, and potential is the electrostatic field at a certain point. This refers to the electrostatic energy (electrical potential energy) possessed by a unit charge in a particle. Generally, the potential difference between a potential at a certain point and a reference potential (for example, ground potential) This is simply called potential or voltage, and potential and voltage are often used synonymously. Therefore, in this specification, unless otherwise specified, potential may be read as voltage. In this specification, voltage may be read as potential.

[0024] In this specification, when an etching process is performed after a photolithography process, The mask formed in the photolithography process is removed.

[0025] (Embodiment 1) In this embodiment, a semiconductor device according to one embodiment of the present invention and a manufacturing method thereof will be described with reference to drawings. Please refer to the following for explanation.

[0026] FIG. 1A shows a liquid crystal display device as an example of a semiconductor device. The display device includes a pixel portion 101, a scanning line driver circuit 104, and a signal line driver circuit 106, each of which is m lines arranged in parallel or approximately in parallel and whose potentials are controlled by the scanning line driving circuit 104 The scanning lines 107 are arranged parallel or approximately parallel to each other, and are driven by a signal line driving circuit 106. The pixel section 101 further includes a matrix. The pixel array has a plurality of pixels 301 arranged in a square shape. The capacitance lines 115 are arranged in rows or approximately parallel to each other. 9, they may be arranged parallel or approximately parallel to each other. The semiconductor memory device 04 and the signal line driver circuit 106 may be collectively referred to as a driver circuit portion.

[0027] Each scanning line 107 corresponds to one of the pixels 301 arranged in m rows and n columns in the pixel section 101. The signal lines 109 are electrically connected to the n pixels 301 arranged in any one row. is m pixels 301 arranged in m rows and n columns, and m pixels 301 arranged in any one of the columns. 1. m and n are both integers of 1 or more. is n pixels 301 arranged in any one of the rows among the pixels 301 arranged in m rows and n columns. 1. Capacitor lines 115 are arranged parallel to each other along the signal line 109. In the case where the pixels 301 are arranged in m rows and n columns, any one of the pixels 301 may be arranged in a matrix of m rows and n columns. The pixel array 302 is electrically connected to m pixels 301 arranged in a column.

[0028] FIG. 1B shows a circuit that can be used for the pixel 301 of the liquid crystal display device shown in FIG. The configuration is shown.

[0029] The pixel 301 shown in FIG. 1B includes a liquid crystal element 132, a transistor 131_1, and a capacitor. The element 133_1 and the element 133_2 are also included.

[0030] The potential of one of the pair of electrodes of the liquid crystal element 132 is appropriately set according to the specifications of the pixel 301. The alignment state of the liquid crystal element 132 is set by the written data. A common potential (common potential) is applied to one of a pair of electrodes of the liquid crystal element 132 in each pixel 301. In addition, one of the pair of electrodes of the liquid crystal element 132 for each row of pixels 301 may be applied. Alternatively, in the case of IPS or FFS mode, the liquid crystal element may be provided with different potentials. It is also possible to connect one of the pair of electrodes of the terminal 132 to the capacitance line CL.

[0031] For example, the liquid crystal display device including the liquid crystal element 132 can be driven in a TN mode, ST mode, or the like. N mode, VA mode, ASM (Axially Symmetric Aligned Micro-cell mode, OCB (Optically Compensated) d Birefringence mode, FLC (Ferroelectric Li quid Crystal) mode, AFLC(AntiFerroelectric) mode Liquid Crystal mode, MVA mode, PVA (Patterned Vertical Alignment) mode, IPS mode, FFS mode, or Even if you use TBA (Transverse Bend Alignment) mode, In addition to the above-mentioned driving method, the liquid crystal display device can be driven by ECB (Electron Beam Controlled) driving method. ctrically Controlled Birefringence) mode, P DLC (Polymer Dispersed Liquid Crystal) mode , PNLC (Polymer Network Liquid Crystal) mode However, the present invention is not limited to these, and the liquid crystal element and its driving method may be used. A variety of formulas can be used.

[0032] Also, a liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent. The liquid crystal element may be configured by the liquid crystal that exhibits the blue phase. Since it is short and optically isotropic, alignment treatment is not required and viewing angle dependency is small.

[0033] In the pixel 301 in the mth row and the nth column, One of the electrodes is electrically connected to the signal line DL_n, and the other is a pair of electrodes of the liquid crystal element 132. The gate electrode of the transistor 131_1 is electrically connected to the other of the scan lines G L_m. The transistor 131_1 is in an on state or an off state. By this, the write control circuit 100 has a function of controlling the writing of data of the data signal.

[0034] One of a pair of electrodes of the capacitor 133_1 is connected to a wiring to which a potential is supplied (hereinafter, a capacitor line CL ) and the other is electrically connected to the other of the pair of electrodes of the liquid crystal element 132. The value of the potential of the capacitance line CL is appropriately set according to the specifications of the pixel 301. The child 133_1 has a function as a storage capacity for storing written data. In the case of the IPS mode or the FFS mode, one of the pair of electrodes of the capacitance element 133_1 is a liquid crystal display. It is also possible for the light emitting diode 132 to be electrically connected to one of the pair of electrodes of the crystal element 132 .

[0035] For example, in a liquid crystal display device having the pixel 301 shown in FIG. The pixels 301 in each row are selected in sequence, the transistors 131_1 are turned on, and a data signal is output. Write the data of the number.

[0036] The pixel 301 to which the data has been written is turned off by turning off the transistor 131_1. By repeating this process row by row, an image can be displayed.

[0037] In this specification and the like, an example of a liquid crystal display device using a liquid crystal element is a transmission type liquid crystal display device. Crystal display device, transflective liquid crystal display device, reflective liquid crystal display device, direct view liquid crystal display device, projection type An example of a liquid crystal element is a device that uses the optical modulation effect of liquid crystal to convert light into light. There is an element that controls the transmission or non-transmission. The element is composed of a pair of electrodes and a liquid crystal layer. The optical modulation of the liquid crystal is achieved by the electric field applied to the liquid crystal (the electric field in the lateral direction). , including a vertical electric field or a diagonal electric field). Examples of liquid crystal elements include nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal, and dye liquid crystal. Discotic liquid crystal, thermotropic liquid crystal, lyotropic liquid crystal, low molecular weight liquid crystal, polymer liquid Polymer-dispersed liquid crystal (PDLC), Ferroelectric liquid crystal, Antiferroelectric liquid crystal, Main-chain liquid crystal, Side-chain high- Examples of such liquid crystals include molecular liquid crystals and banana-shaped liquid crystals.

[0038] In addition, instead of a liquid crystal display device, a display element, a display device, a light-emitting device, etc. may be used as an example of a semiconductor device. In addition, a display element, a display device having a display element, a light emitting device, etc. can be used. A light emitting device, which is a device having a light emitting element, can be used in various forms, or The display element, the display device, the light-emitting element, or the light-emitting device may include various elements. Examples include LEDs (white LEDs, red LEDs, green LEDs, blue LEDs, etc.), transistors, (transistors that emit light according to electric current), electron-emitting devices, liquid crystal devices, electronic ink, Electrophoretic element, Grating light valve (GLV), Plasma display (PDP) , MEMS (Micro-Electro-Mechanical Systems), Digital Micromirror Device (DMD), DMS (Digital Micro Shutter), IMOD (Interface Modulation Device) Fairing modulation elements, piezoelectric ceramic displays, carbon nanotubes Tubes, etc., change in contrast, brightness, reflectance, transmittance, etc. due to electromagnetic effects. One example of a display device using electron-emitting devices is a filter. Field Emission Display (FED) or Single Ended Emission Display (SED) D:Surface-conduction Electron-emitter Di Examples of display devices using electronic ink or electrophoretic elements include Examples include electronic paper.

[0039] Next, a specific example of a liquid crystal display device using liquid crystal elements in the pixels 301 will be described. Here, a top view of the pixel 301 shown in FIG. 1(B) is shown in FIG. 2. The counter electrode and the liquid crystal element are omitted.

[0040] In FIG. 2, the conductive film 304c functioning as the scanning line is oriented in a direction substantially perpendicular to the signal line ( The conductive film 310d, which functions as a signal line, is provided so as to extend in the center (left and right direction). The capacitor extends in a direction substantially perpendicular to the line (vertical direction in the figure). The conductive film 310f is provided so as to extend in a direction parallel to the signal lines. The conductive film 304c is electrically connected to the scanning line driver circuit 104 (see FIG. 1A). The conductive film 310d functions as a signal line, and the conductive film 310f functions as a capacitance line. is electrically connected to a signal line driver circuit 106 (see FIG. 1A).

[0041] The transistor 103 is provided in a region where the scanning line and the signal line intersect. The gate electrode 304c functions as a conductive film, and the gate insulating film 304b functions as a gate electrode. First, an oxide semiconductor film 308b in which a channel region is formed on a gate insulating film; The conductive film 310d and the conductive film 310e function as a source electrode and a drain electrode. Note that the conductive film 304c also functions as a scan line and overlaps with the oxide semiconductor film 308b. The overlapping region functions as a gate electrode of the transistor 103. 3, and a region overlapping with the oxide semiconductor film 308b of the transistor 103 In FIG. 2, the scanning line functions as a source electrode or a drain electrode of the In terms of shape, the end portion is located outside the end portion of the oxide semiconductor film 308b. The lines function as a light-shielding film that blocks light from a light source such as a backlight. The oxide semiconductor film 308b included in the transistor is not irradiated with light, and the electrical characteristics of the transistor are not changed. This can suppress movement.

[0042] In addition, the conductive film 310e has a light-transmitting property that functions as a pixel electrode in the opening 362c. The conductive film 316b is electrically connected to the conductive film 316b.

[0043] The capacitor 105 includes a light-transmitting conductive film 308c formed over a gate insulating film and a pixel A light-transmitting conductive film 316b serving as a base electrode and a That is, the capacitance element 105 is made of a transparent dielectric film formed of a nitride insulating film. The capacitor 105 has a conductive film that functions as a capacitor line in the opening 362. It is connected to the conductive film 310f.

[0044] Here, the light-transmitting conductive film 316b is preferably rectangular as shown in FIG. However, one embodiment of the present invention is not limited thereto. The film 316b is provided in a liquid crystal display device of FFS mode, IPS mode, MVA mode, etc. It is possible to make the pixel electrode have a structure having slits or a comb-like shape, like the pixel electrode to be used.

[0045] In this way, since the capacitor 105 has a light-transmitting property, the capacitor 105 is large and can be placed in the pixel 301. Therefore, the aperture ratio can be increased, typically by 55%. or more, preferably 60% or more, and the charge capacity is increased. For example, in a high-resolution liquid crystal display device, the pixel surface This reduces the capacitance and the area of ​​the capacitance element. In this embodiment, however, the amount of charge stored in the capacitor is small. Since the capacitor 105 has a light-transmitting property, the capacitor is provided in each pixel. In the conventional liquid crystal display, the aperture ratio can be increased while obtaining a sufficient charge capacity. It is suitable for use in high-resolution liquid crystal display devices having a resolution of 200 ppi or more, and even 300 ppi or more. There can be.

[0046] In addition, the pixel 301 shown in FIG. 2 has a side that is parallel to the conductive film 304c that functions as a scan line. In comparison, the side parallel to the conductive film 310d functioning as a signal line is shorter, and The conductive film 310f functioning as a line is parallel to the conductive film 310d functioning as a signal line. As a result, the area of ​​the conductive film 310f in the pixel 301 is reduced. This allows the aperture ratio to be increased. Since the conductive film 310f is in direct contact with the light-transmitting conductive film 308c without using a connection electrode, Furthermore, the aperture ratio can be increased.

[0047] In addition, according to one embodiment of the present invention, the aperture ratio can be increased even in a high-resolution liquid crystal display device. This allows efficient use of light from a light source such as a backlight, and thus makes it possible to improve the liquid crystal display device The power consumption can be reduced.

[0048] Next, a cross-sectional view taken along dashed line CD in FIG. 2 is shown in FIG. 3. In FIG. 3, A driver circuit section including a scanning line driver circuit 104 and a signal line driver circuit 106 (top view omitted) A cross-sectional view of the semiconductor device is shown in FIG. A liquid crystal display device will now be described.

[0049] The liquid crystal display device shown in this embodiment has a liquid crystal display device between a pair of substrates (a substrate 302 and a substrate 342). The element 322 is sandwiched.

[0050] The liquid crystal element 322 is connected to a light-transmitting conductive film 316b above the substrate 302 to control the alignment. The liquid crystal layer 320 and the conductive film 352 are connected to the alignment film 318. The light-transmitting conductive film 316b is connected to one of the electrodes of the liquid crystal element 322. The conductive film 350 serves as the other electrode of the liquid crystal element 322 .

[0051] Thus, a liquid crystal display device is a device that has liquid crystal elements. The liquid crystal display device includes a driving circuit for driving a plurality of pixels. A control circuit, a power supply circuit, a signal generating circuit, a backlight module, etc., are arranged in It is also called a liquid crystal module.

[0052] In the driver circuit portion, a conductive film 304a functions as a gate electrode, and a gate insulating film The insulating film 305 and the insulating film 306 functioning as a channel region are formed in the oxide semiconductor film 30. 8a, the conductive film 310a and the conductive film 310b functioning as a source electrode and a drain electrode, The oxide semiconductor film 308a is provided over a gate insulating film. In addition, insulating films 312 and 314 are provided on the conductive films 310a and 310b. It is provided as a protective film.

[0053] In the pixel portion, a conductive film 304c functions as a gate electrode, and a gate insulating film The insulating film 305 and the insulating film 306 are formed on the gate insulating film. a conductive film 310 serving as a source electrode and a drain electrode; d and the conductive film 310e form the transistor 103. The oxide semiconductor film 308b is The insulating film 310 is formed on the gate insulating film. 12. An insulating film 314 is provided as a protective film.

[0054] In addition, a light-transmitting conductive film 316b functioning as a pixel electrode is formed between the insulating film 312 and the insulating film 316b. The insulating film 314 is connected to the conductive film 310e through an opening provided therein.

[0055] In addition, a light-transmitting conductive film 308c functioning as one electrode and a dielectric film The insulating film 314 serving as the other electrode and the light-transmitting conductive film 316b serving as the other electrode form a capacitor. The light-transmitting conductive film 308c is provided over the gate insulating film. .

[0056] In the driving circuit section, a conductive film formed simultaneously with the conductive film 304a and the conductive film 304c is The conductive film 304b is the same as the conductive film 310a, the conductive film 310b, the conductive film 310d, and the conductive film 310e. The conductive film 310c formed at the same time is a conductive film 316b having light-transmitting properties. The connection is made through a light-transmitting conductive film 316a.

[0057] The conductive film 304b and the light-transmitting conductive film 316a are formed by the insulating film 306, the insulating film 312, The connection is made through an opening provided in the insulating film 305 and the insulating film 306. The conductive film 316a having a light-transmitting property is a conductive film having a light-transmitting property. The connection is made through an opening provided in the insulating film 306. A nitride insulating film is used as 314 .

[0058] In this embodiment, the light-transmitting conductive film 30 which is one electrode of the capacitor 105 In order to increase the conductivity of 8c, an opening is provided in the insulating film 312. The conductive film 308c having a light-transmitting property is in contact with the insulating film 314 formed of a nitride insulating film. The reason for the increased conductivity will be explained in detail later.

[0059] Here, the components of the display device shown in FIG. 3 will be described below.

[0060] A conductive film 304a, a conductive film 304b, and a conductive film 304c are formed on the substrate 302. The conductive film 304a functions as a gate electrode of a transistor in the driver circuit portion. The conductive film 304c is formed in the pixel portion 101 and serves as a gate electrode of a transistor in the pixel portion. The conductive film 304b is formed in the scanning line driver circuit 104 and functions as a conductive film 3 Connect to 10c.

[0061] There is no particular restriction on the material of the substrate 302, but it should be strong enough to withstand the subsequent heat treatment. For example, glass substrates, ceramic substrates, quartz substrates, and sa A fire substrate or the like may be used as the substrate 302. Also, silicon, silicon carbide, etc. Single crystal semiconductor substrates, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, It is also possible to use SOI substrates, etc., and semiconductor elements are provided on these substrates. The substrate 302 may be a glass substrate. Combined, 6th generation (1500mm x 1850mm), 7th generation (1870mm x 2200mm ), 8th generation (2200mm x 2400mm), 9th generation (2400mm x 2800mm ), 10th generation (2950mm x 3400mm) and other large area substrates, A liquid crystal display device can be manufactured.

[0062] In addition, a flexible substrate is used as the substrate 302, and a transistor is formed directly on the flexible substrate. Alternatively, a release layer may be provided between the substrate 302 and the transistor. After completing a part or the whole of the element part on it, it is separated from the substrate 302 and attached to another substrate. In this case, the transistors can be mounted on substrates with poor heat resistance or flexible substrates. It can also be printed on other circuit boards.

[0063] The conductive film 304a, the conductive film 304b, and the conductive film 304c may be made of aluminum, chromium, A metal element selected from copper, tantalum, titanium, molybdenum, and tungsten, or The alloy is formed by using an alloy containing the above-mentioned metal elements as components or an alloy combining the above-mentioned metal elements. In addition, one or more of manganese and zirconium may be selected. A metal element may be used. It may be a single layer structure or a laminated structure of two or more layers. For example, aluminum containing silicon A single-layer structure of the film, a two-layer structure of a titanium film laminated on an aluminum film, a titanium nitride film laminated on a titanium nitride film A two-layer structure in which a tungsten film is laminated on a titanium nitride film, a two-layer structure in which a tungsten film is laminated on a titanium nitride film, A two-layer structure in which a tungsten film is laminated on a tungsten film or a tungsten nitride film, a titanium film and A three-layer structure is formed in which an aluminum film is laminated on the titanium film, and a titanium film is further formed on the aluminum film. In addition, aluminum, titanium, tantalum, tungsten, molybdenum, chromium, etc. A film of an element selected from the group consisting of chromium, neodymium, and scandium, or an alloy film made by combining multiple elements; Alternatively, a nitride film may be used.

[0064] The conductive films 304a, 304b, and 304c are made of indium tin oxide, an oxide Indium oxide containing tungsten oxide, Indium zinc oxide containing tungsten oxide , indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium Conductive materials with light transmission properties, such as indium zinc oxide and indium tin oxide doped with silicon oxide In addition, a combination of the above-mentioned conductive material having light-transmitting properties and the above-mentioned metal element may be used. It may also be a layered structure.

[0065] In addition, the conductive film 304a, the conductive film 304b, and the conductive film 304c are used as a part of the gate insulating film. Between the insulating film 305 that functions, an In-Ga-Zn-based oxynitride semiconductor film, an In-Sn-based oxynitride semiconductor film, and Nitride semiconductor film, In-Ga-based oxynitride semiconductor film, In-Zn-based oxynitride semiconductor film, Sn The semiconductor films are made of In-based oxynitride semiconductor films, In-based oxynitride semiconductor films, and metal nitride films (InN, ZnN, etc.). These films have a work function of 5 eV or more, preferably 5.5 eV or more, and are Since the electron affinity of the oxide semiconductor is larger than that of the oxide semiconductor, The threshold voltage of the transistor can be shifted to the positive side, and the switching characteristic of the transistor can be changed to the normally-off characteristic. For example, when an In-Ga-Zn-based oxynitride semiconductor film is used, Specifically, the nitrogen concentration in the oxide semiconductor film 308a is higher than that in the oxide semiconductor film 308b. An In-Ga-Zn-based oxynitride semiconductor film with a concentration of 7 atomic % or more is used.

[0066] An insulating film 3 is formed on the substrate 302 and the conductive films 304a, 304c, and 304b. The insulating film 305 and the insulating film 306 are formed on the driving circuit section. The function as a gate insulating film of the transistor and a gate insulating film of the transistor of the pixel portion 101 Possesses the ability.

[0067] The insulating film 305 may be, for example, silicon nitride, silicon oxynitride, aluminum nitride, It is preferable to form the insulating film using a nitride such as aluminum oxide nitride.

[0068] The insulating film 306 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, Silicon nitride, aluminum oxide, hafnium oxide, gallium oxide or Ga-Zn-based gold The insulating film 306 may be formed as a single layer or a laminated layer. , hafnium silicate (HfSi x O y ), nitrogen-doped hafnium silicate, Hafnium Aluminate (HfAl x O y ), nitrogen-doped hafnium aluminate By using high-k materials such as hafnium oxide and yttrium oxide, This can reduce the gate leakage of the capacitor.

[0069] The total thickness of the insulating film 305 and the insulating film 306 is preferably 5 nm or more and 400 nm or less. Preferably, the thickness is 10 nm or more and 300 nm or less, and more preferably, 50 nm or more and 250 nm or less. It is good.

[0070] An oxide semiconductor film 308 a, an oxide semiconductor film 308 b, and a light-transmitting The oxide semiconductor film 308a overlaps with the conductive film 304a. It is formed at a position where the gate electrode 14 is folded and functions as a channel region of the transistor of the driving circuit section. The oxide semiconductor film 308b is formed in a position overlapping with the conductive film 304c. The light-transmitting conductive film 308c functions as a channel region of the capacitor 1. It functions as one of the electrodes of 05.

[0071] The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308 c is typically an In-Ga oxide film, an In-Zn oxide film, or an In-M-Zn oxide film (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf).

[0072] Note that the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film When 308c is an In-M-Zn oxide film, the sum of In and M is 100 atomic %, the atomic ratio of In and M is preferably 25 atomic % or more. M is less than 75 atomic %, and more preferably In is 34 atomic % or more. is less than 66 atomic%.

[0073] The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308 c is an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more. In this way, by using an oxide semiconductor with a wide energy gap, The off-state current of the transistor can be reduced.

[0074] The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308 The thickness of c is 3 nm or more and 200 nm or less, preferably 3 nm or more and 100 nm or less, and more preferably The thickness is preferably 3 nm or more and 50 nm or less.

[0075] The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308 c) In-Ga-Zn with an atomic ratio of In:Ga:Zn=1:1:1 or 3:1:2 An oxide can be used. The atomic ratios of the conductive film 308c having a light-transmitting property are calculated by subtracting the above atomic ratios from the atomic ratios of the conductive film 308c having a light-transmitting property. This includes a fluctuation of plus or minus 20%.

[0076] The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308 Both of the gate insulating film and the gate insulating film 306 are formed on the gate insulating film. Specifically, the oxide semiconductor film 308 is different from the oxide semiconductor film 308a and the oxide semiconductor film 308b in that the The impurity concentration of the conductive film 308c having the optical properties is high. The hydrogen concentration in the compound semiconductor film 308b is 5×10 19 atoms / cm 3 Less than, good Preferably 5 x 10 18 atoms / cm 3 Less than 1 x 10 18 atoms / c m 3Less than or equal to 5×10 17 atoms / cm 3 Below, more preferably 1× 10 16 atoms / cm 3 The hydrogen contained in the light-transmitting conductive film 308c is as follows: The concentration is 8 x 10 19 atoms / cm 3 More than 1×10 20 atoms / c m 3 More preferably, 5×10 20 atoms / cm 3 That is all. In addition, Compared with the conductive film 308a and the oxide semiconductor film 308b, the conductive film 308c has a light-transmitting property. The hydrogen concentration is twice as high, preferably 10 times or more.

[0077] The light-transmitting conductive film 308c is formed by the oxide semiconductor film 308a and the oxide semiconductor film 3 The resistivity of the light-transmitting conductive film 308c is lower than that of the oxide semiconductor film 308b. 08a, the resistivity of the oxide semiconductor film 308b is 1×10 -8 1×10 times more -1 Less than double It is preferable to use a concentration of 1×10 -3 Ωcm or more 1×10 4 Less than Ωcm, even better Preferably, the resistivity is 1×10 -3 Ωcm or more 1×10 -1 It is preferable that the resistivity is less than Ωcm.

[0078] In the oxide semiconductor films 308a and 308b, When silicon or carbon is contained in the oxide semiconductor film 308a and the oxide semiconductor film 308b, As a result, oxygen vacancies increase and the oxide semiconductor film 308a becomes n-type. The concentration of silicon and carbon in the semiconductor film 308b (obtained by secondary ion mass spectrometry) Concentration) is 2 x 10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0079] In addition, in the oxide semiconductor film 308a and the oxide semiconductor film 308b, the secondary ion mass distribution The concentration of alkali metals or alkaline earth metals obtained by the precipitation method is 1×10 18 ato ms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 Below: Alkaline gold When metals and alkaline earth metals are bonded to an oxide semiconductor, they may generate carriers. The off-state current of the transistor may be increased. a) Reducing the concentration of alkali metal or alkaline earth metal in the oxide semiconductor film 308b is preferred.

[0080] In addition, when the oxide semiconductor film 308a and the oxide semiconductor film 308b contain nitrogen, This generates electrons that are carriers, increases the carrier density, and makes it easier to become n-type. Transistors using oxide semiconductors, which are widely used in semiconductor manufacturing, tend to be normally-on. In addition, it is preferable that nitrogen be reduced as much as possible in the oxide semiconductor film. For example, the nitrogen concentration obtained by secondary ion mass spectrometry is 5×10 18 atoms / cm 3 It is preferable to do the following:

[0081] The oxide semiconductor films 308a and 308b are made of oxide semiconductor films having low carrier density. For example, the oxide semiconductor film 308a and the oxide semiconductor film 308b are made of a tantalum oxide semiconductor material. Carrier density is 1×10 17 pieces / cm 3 Less than or equal to 1×10 15 pieces / cm 3 Below, More preferably, 1×10 13 pieces / cm 3 Less than or equal to 1×10 11 pieces / cm 3 Below The lower oxide semiconductor film is used.

[0082] In addition, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use a material with an appropriate composition according to the required properties (e.g., the resultant mobility, threshold voltage, etc.). In order to obtain semiconductor characteristics of the transistor, the oxide semiconductor film 308a and the oxide semiconductor film 3 Carrier density, impurity concentration, defect density, atomic ratio of metal elements to oxygen, and interatomic distance of 08b It is preferable to make the material suitable in terms of the material properties, density, etc.

[0083] The oxide semiconductor film 308a and the oxide semiconductor film 308b are formed by the insulating film 306 and the insulating film 312. The oxide semiconductor film is in contact with a film formed of a material capable of improving interface characteristics with the oxide semiconductor film, such as Therefore, the oxide semiconductor films 308a and 308b function as semiconductors. In addition, the transistor including the oxide semiconductor film 308a and the oxide semiconductor film 308b has excellent electrical conductivity. It has temperamental properties.

[0084] Note that the oxide semiconductor films 308a and 308b have low impurity concentrations. By using an oxide semiconductor film with a low density of defect states, a transistor with excellent electrical characteristics can be manufactured. Here, the impurity concentration is low and the defect level density is low ( High purity intrinsic or substantially high purity intrinsic. In the case of an oxide semiconductor, which is substantially a high-purity intrinsic oxide semiconductor, there are few carrier generation sources, and therefore the carrier density is low. Therefore, a channel region can be formed in the oxide semiconductor film. The transistors that are formed have electrical characteristics in which the threshold voltage is negative (also called normally-on). In addition, the product may be highly purified or substantially highly purified. Since the oxide semiconductor film has a low density of defect states, the density of trap states may also be low. In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a significantly low off-state current. Very small, with a channel width of 1×10 6 Even if the element has a channel length L of 10 μm, When the voltage between the source and drain electrodes (drain voltage) is in the range of 1V to 10V, The current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1×10 -13 Below A Therefore, a channel region is formed in the oxide semiconductor film. Such a transistor may have small fluctuations in electrical characteristics and become a highly reliable transistor. Note that it takes a long time for charges trapped in the trap states of the oxide semiconductor film to disappear. The distance between the charges is long and they can behave as if they were fixed charges. Therefore, the trap level density A transistor in which a channel region is formed in an oxide semiconductor film with high thermal conductivity has unstable electrical characteristics. Impurities include hydrogen, nitrogen, alkali metals, and alkaline earth metals. etc.

[0085] On the other hand, the light-transmitting conductive film 308c is formed of nitrogen in the opening 362 (see FIG. 6A). The insulating film 314 is in contact with the insulating film 314 formed of a nitride insulating film. For example, a material that prevents water, alkali metals, alkaline earth metals, etc. from diffusing into an oxide semiconductor film. The insulating film 314 is a film formed of a material containing hydrogen. The oxide semiconductor film 308b is formed at the same time as the conductive film 308a. In the oxide semiconductor film, hydrogen is bonded to oxygen to generate electrons that serve as carriers. As a result, the oxide semiconductor film has high electrical conductivity and functions as a conductor. Here, the oxide semiconductor film 308a and the oxide semiconductor film 308 The oxide semiconductor film 308a and the oxide semiconductor film 308b are mainly composed of the same material as that of the oxide semiconductor film 308a and the oxide semiconductor film 308b. The metal oxide having a higher electrical conductivity than 308b is then used as a light-transmitting conductive film. It's called 308c.

[0086] In addition, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308c may be, for example, a non-single crystal structure. The non-single crystal structure may be, for example, a CAAC -OS(C Axis Aligned Crystalline Oxide Sem The term "crystalline structure" includes a polycrystalline structure, a microcrystalline structure (described below), or an amorphous structure. In the non-single crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states. Note that the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting The conductive film 308c having the same crystallinity.

[0087] Note that the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308c is an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, and CAAC-OS The mixed film may be a film having two or more types of regions of a single crystal structure, a region of a single crystal structure, or a region of a single crystal structure. , amorphous structure region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single crystal structure region, The mixed film may have two or more regions of any of the crystal structure regions. , amorphous structure region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single crystal structure region, There are cases where the crystal structure has a laminated structure of two or more types of regions.

[0088] However, one aspect of the embodiment of the present invention is not limited to this. In some cases, it is possible that 8c is not in contact with the insulating film 314.

[0089] In addition, one aspect of the embodiment of the present invention is not limited to this. In some cases, the oxide semiconductor film c may be different from the oxide semiconductor film 308a or the oxide semiconductor film 308b. In that case, the light-transmitting conductive film 308c may be formed by a process including an oxide film. The semiconductor film 308a and the oxide semiconductor film 308b may be made of different materials. The light-transmitting conductive film 308c is made of indium tin oxide (hereinafter, referred to as ITO). The insulating film may be formed using indium zinc oxide or the like.

[0090] In the liquid crystal display device described in this embodiment, a capacitor is formed in addition to an oxide semiconductor film of a transistor. A light-transmitting conductive film that functions as a pixel electrode is formed. The other electrode of the capacitor element is used. Since the step of forming a conductive film is not required, the manufacturing steps of the liquid crystal display device can be reduced. The element has a light-transmitting property because the pair of electrodes is formed of a light-transmitting conductive film. As a result, the area occupied by the capacitive element can be increased while increasing the aperture ratio of the pixel.

[0091] Conductive film 310a, conductive film 310b, conductive film 310c, conductive film 310d, conductive film 310e Conductive materials include aluminum, titanium, chromium, nickel, copper, yttrium, and di The elemental metals zinc, molybdenum, silver, tantalum, or tungsten; or The alloy containing this as the main component is used as a single layer structure or a multilayer structure. A single-layer structure of an aluminum film containing titanium, a two-layer structure of an aluminum film on a titanium film, A two-layer structure in which a titanium film is laminated on a stainless steel film, and a copper-magnesium-aluminum alloy film is laminated on A two-layer structure in which a copper film is laminated, a titanium film or titanium nitride film, and the titanium film or titanium nitride film are laminated. An aluminum film or copper film is laminated on the silicon film, and a titanium film or nitride film is further laminated on top of that. A three-layer structure that forms a titanium film, a molybdenum film or a molybdenum nitride film, and the molybdenum An aluminum film or a copper film is laminated on the film or the molybdenum nitride film, and then an aluminum film or a copper film is laminated on the film or the molybdenum nitride film. There are three-layer structures in which a molybdenum film or a molybdenum nitride film is formed on the indium oxide film. Transparent conductive materials including aluminum, tin oxide, or zinc oxide may also be used.

[0092] In addition, by forming the conductive film 310c so as to overlap with the conductive film 304b, Since the border can be reduced, the area occupied by the driving circuit unit can be reduced. This makes it possible to narrow the frame of the display device.

[0093] The insulating film 306, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film Conductive film 308c, conductive film 310a, conductive film 310b, conductive film 310c, conductive film 310d An insulating film 312 and an insulating film 314 are formed on the conductive film 310e. Like the insulating film 306, the insulating film 306 is made of a material capable of improving interface characteristics with the oxide semiconductor film. It is preferable to use an oxide insulating film, and the insulating film can be formed using an oxide insulating film. The film 312 is formed by laminating an insulating film 312a and an insulating film 312b.

[0094] The insulating film 312a is an oxide insulating film that transmits oxygen. When forming the insulating film 312b to be formed on the oxide semiconductor film 308a, the oxide semiconductor film 3 The conductive film 308b and the light-transmitting conductive film 308c also function as a film for reducing damage to the conductive film 308b and the light-transmitting conductive film 308c.

[0095] The insulating film 312a has a thickness of 5 nm to 150 nm, preferably 5 nm to 500 nm. Silicon oxide, silicon oxynitride, etc. having a thickness of 0 nm or less can be used. Among them, the silicon oxynitride film is a film having a composition in which the oxygen content is higher than the nitrogen content. A silicon nitride oxide film is a film that contains more nitrogen than oxygen. Refers to...

[0096] In addition, it is preferable that the insulating film 312a has a small amount of defects. Therefore, the spin density of the signal at g=2.001 originating from the silicon dangling bond is Degree is 3 x 10 17 spins / cm 3 This is because the insulating film 312 If the density of defects in a is high, oxygen will bind to the defects, and the insulating film 312a will This is because the oxygen permeability rate decreases.

[0097] In addition, the insulating film 312a, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting It is preferable that the number of defects at the interface with the conductive film 308c having the property is small. The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting The spin density of the signal appearing at g=1.93 due to the defect in the conductive film 308c is 1×1 0 17 spins / cm 3 It is preferably below the lower detection limit.

[0098] In the insulating film 312a, all of the oxygen that entered the insulating film 312a from the outside is Some oxygen does not move outside the insulating film 312a and remains in the insulating film 312a. As oxygen enters the insulating film 312a, oxygen contained in the insulating film 312a moves out of the insulating film 312a. This may cause oxygen transfer in the insulating film 312a.

[0099] When an oxide insulating film that transmits oxygen is formed as the insulating film 312a, Oxygen desorbed from the insulating film 312b is transported through the insulating film 312a to the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308c. This can be done.

[0100] An insulating film 312b is formed in contact with the insulating film 312a. The oxide insulating film is formed using an oxide insulating film containing more oxygen than the oxygen that satisfies the stoichiometric composition. The oxide insulating film containing more oxygen than the stoichiometric composition loses some of the oxygen by heating. The oxide insulating film containing more oxygen than the stoichiometric composition has a T In the DS analysis, the amount of oxygen desorbed was 1.0 x 10 18 atoms / cm 3 More than 3.0×10 20atoms / cm 3 The oxide insulating film is .

[0101] The insulating film 312b has a thickness of 30 nm to 500 nm, preferably 50 nm or more. A silicon oxide film, a silicon oxynitride film, or the like having a thickness of 400 nm or less can be used.

[0102] In addition, it is preferable that the insulating film 312b has a small amount of defects. Therefore, the spin density of the signal at g=2.001 originating from the silicon dangling bond is Degree is 1.5 x 10 18 spins / cm 3 Less than or even 1×10 18 spins / cm 3 The insulating film 312b is preferably an oxide film or less than the insulating film 312a. The semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308c are separated from each other. Since the insulating film 312 is made of a thin film, the insulating film 312 may have a higher defect density than the insulating film 312a.

[0103] The insulating film 314 is made of a blocker such as oxygen, hydrogen, water, an alkali metal, or an alkaline earth metal. By providing the nitride insulating film having a masking effect, the oxide semiconductor film 308a and the oxide semiconductor The diffusion of oxygen from the conductive film 308b and the light-transmitting conductive film 308c to the outside can be prevented. The nitride insulating film can be made of silicon nitride, silicon oxynitride, aluminum nitride, Aluminum oxide nitride, etc.

[0104] In addition, the material has a blocking effect against oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. An oxide insulating film having a blocking effect against oxygen, hydrogen, water, etc. is provided over the nitride insulating film. As the oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like, an oxide insulating film may be used. Aluminum, aluminum oxide nitride, gallium oxide, gallium oxide nitride, yttrium oxide Examples include yttrium oxide, yttrium nitride, hafnium oxide, and hafnium nitride. In order to control the charge capacity of the element, oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. A nitride insulating film or an oxide insulating film is appropriately provided on the nitride insulating film having a blocking effect. This is also fine.

[0105] In addition, a light-transmitting conductive film 316a and a light-transmitting conductive film 31 The light-transmitting conductive film 316a has an opening 364a (FIG. 6(C)). 3B) is electrically connected to the conductive film 304b and the conductive film 310c. The conductive film 304b functions as a connection electrode that connects the conductive film 310c to the conductive film 304b. The conductive film 316b is electrically connected to the conductive film 310e in the opening 364b (see FIG. 6C). The conductive film 316b having a light-transmitting property is It can function as one of a pair of electrodes of a capacitor.

[0106] In order to form a connection structure in which the conductive film 304b and the conductive film 310c are in direct contact with each other, Before forming the conductive film 310c, a pattern is formed in order to form openings in the insulating films 305 and 306. However, as shown in Figure 3, the mask is transparent. The conductive film 316a having the following structure connects the conductive film 304b and the conductive film 310c. There is no need to form a connection portion where the conductive film 304b and the conductive film 310c are in direct contact with each other. In other words, the number of steps in the manufacture of a liquid crystal display device can be reduced. is possible.

[0107] The light-transmitting conductive film 316a and the light-transmitting conductive film 316b are formed of tungsten oxide. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, titanium oxide Indium oxide containing titanium, indium tin oxide containing titanium oxide, ITO, indium Conductive materials with light-transmitting properties such as indium zinc oxide and indium tin oxide doped with silicon oxide Materials can be used.

[0108] The alignment film 318 may be made of an organic resin such as polyimide. The film thickness should be 40 nm or more and 100 nm or less, and more preferably 50 nm or more and 90 nm or less. By setting the film thickness in this range, the pretilt angle of the liquid crystal material can be increased. It is possible. By increasing the pretilt angle of the liquid crystal material, disclination can be reduced. It is possible to do so.

[0109] In addition, a film having color (hereinafter, referred to as a color film 346) is formed on the substrate 342. The colored film 346 functions as a color filter. An adjacent light-shielding film 344 is formed on the substrate 342. The light-shielding film 344 is a black matrix. The colored film 346 does not necessarily have to be provided. For example, a liquid crystal display may be used. In some cases, such as when the display device is black and white, the color film 346 may not be provided.

[0110] The colored film 346 may be any colored film that transmits light in a specific wavelength range. For example, A red (R) color filter that transmits light in the red wavelength range, and a green (G) color filter that transmits light in the green wavelength range. A green (G) color filter transmits light in the blue wavelength range, and a blue (B) color filter transmits light in the blue wavelength range. A filter or the like can be used.

[0111] The light-shielding film 344 may be made of a metal or other material as long as it has a function of blocking light in a specific wavelength range. Alternatively, an organic insulating film containing a black pigment or the like can be used.

[0112] In addition, an insulating film 348 is formed on the colored film 346. The insulating film 348 is planarized. The function of the colored film 346 is to prevent impurities contained therein from diffusing toward the liquid crystal element. It has the function of controlling

[0113] In addition, a conductive film 350 is formed on the insulating film 348. The conductive film 350 is The liquid crystal element has a function as the other of the pair of electrodes. An alignment film 318 is formed over the conductive film 316a and the light-transmitting conductive film 316b. An alignment film 352 is formed on the liquid crystal display 350 .

[0114] In addition, the conductive film 316a having a light-transmitting property, the conductive film 316b having a light-transmitting property, and the conductive film 350 A liquid crystal layer 320 is formed between the liquid crystal layer 320 and the sealing material (not shown). The space between the substrate 302 and the substrate 342 is sealed using a sealing material. In order to prevent the intrusion of moisture or the like from the inside, it is preferable that the insulating layer is in contact with an inorganic material.

[0115] In addition, the conductive film 316a having a light-transmitting property, the conductive film 316b having a light-transmitting property, and the conductive film 350 A spacer may be provided between the liquid crystal layer 320 and the substrate 310 to maintain the thickness of the liquid crystal layer 320 (also called the cell gap). stomach.

[0116] Regarding a method for manufacturing an element portion provided on a substrate 302 in the liquid crystal display device shown in FIG. 4 to 7. In this embodiment, the element portion provided on the substrate 302 is In this case, it refers to the region sandwiched between the substrate 302 and the alignment film 318.

[0117] First, prepare a substrate 302. Here, a glass substrate is used as the substrate 302.

[0118] Next, a conductive film is formed on the substrate 302, and the conductive film is processed into a desired region. The conductive film 304a, the conductive film 304b, and the conductive film 304c are formed. The formation of the film 304b and the conductive film 304c is carried out by forming a mask by the first patterning in a desired region. The mask can be formed by forming a mask and then etching the areas not covered by the mask. (See Figure 4(A)).

[0119] The conductive films 304a, 304b, and 304c are typically formed by deposition. The film can be formed by a deposition method, a CVD method, a sputtering method, a spin coating method, or the like.

[0120] Next, an insulating film is formed on the substrate 302 and the conductive films 304a, 304b, and 304c. A film 305 is formed, and an insulating film 306 is formed over the insulating film 305 (see FIG. 4A).

[0121] The insulating film 305 and the insulating film 306 are formed by a sputtering method, a CVD method, or the like. When the insulating film 305 and the insulating film 306 are successively formed in a vacuum, impurities are easily removed. This is preferable because it suppresses the inclusion of

[0122] Next, an oxide semiconductor film 307 is formed over the insulating film 306 (see FIG. 4B).

[0123] The oxide semiconductor film 307 can be formed by a sputtering method, a coating method, a pulsed laser deposition method, a laser deposition method, or the like. The thin film can be formed by using a method such as ablation.

[0124] Next, the oxide semiconductor film 307 is processed into desired regions, so that an island-shaped oxide semiconductor film The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d are formed. The semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d are formed by a desired method. A mask is formed on the region by a second patterning, and the region not covered by the mask is The etching can be performed by dry etching, Wet etching, or a combination of both can be used (Figure 4 (See (C)).

[0125] After that, heat treatment is performed to form the oxide semiconductor film 308a and the oxide semiconductor film 308b. Hydrogen, water, and the like contained in the oxide semiconductor film 308d are released, and the oxide semiconductor film 308a is Hydrogen and water contained in the oxide semiconductor films 308b and 308d may be reduced. As a result, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308c are highly purified. The heat treatment temperature is typically 250 The temperature is set to 650° C. or higher, and preferably 300° C. or higher and 500° C. or lower. The temperature is typically 300° C. or higher and 400° C. or lower, preferably 320° C. or higher and 370° C. or lower. By doing so, it is possible to reduce warping and shrinkage of the substrate even in the case of a large substrate. This improves the yield.

[0126] The heat treatment can be performed using an electric furnace, an RTA device, or the like. This allows heat treatment at a temperature above the distortion point of the substrate for a short period of time. It is possible to shorten the heat treatment time and reduce the warping of the substrate during heat treatment. This is particularly preferable for large area substrates.

[0127] The heat treatment is carried out in an atmosphere of nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably air at less than 1 ppm, preferably less than 10 ppb), or rare gases (argon, helium The above-mentioned nitrogen, oxygen, ultra-dry air, or rare gas may be added to the water atmosphere. It is preferable that the material does not contain hydrogen, water, etc. Also, after heat treatment in a nitrogen or rare gas atmosphere, Alternatively, the oxide semiconductor film may be heated in an oxygen or ultra-dry air atmosphere. Hydrogen, water, and the like can be released and oxygen can be supplied to the oxide semiconductor film. As a result, the amount of oxygen vacancies in the oxide semiconductor film can be reduced.

[0128] Next, the insulating film 306, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide A conductive film 309 is formed over the semiconductor film 308d (see FIG. 5A).

[0129] The conductive film 309 can be formed by, for example, a sputtering method.

[0130] Next, the conductive film 309 is processed into a desired region to form a conductive film 310a, a conductive film 310b, and a conductive film 310c. , the conductive film 310c, the conductive film 310d, and the conductive film 310e are formed. , the conductive film 310b, the conductive film 310c, the conductive film 310d, and the conductive film 310e are formed in a desired region. A mask is formed by a third patterning, and the area not covered by the mask is etched. It can be formed by etching (see FIG. 5(B)).

[0131] Note that by forming the conductive film 310c so as to overlap with the conductive film 304b, The conductive film 304b and the conductive film 310c are electrically connected to each other through a light-transmitting conductive film 316a. Therefore, the area occupied by the driver circuit can be reduced. In addition, the conductive film 316a having a light-transmitting property and the conductive film 310c having a light-transmitting property are in contact with each other. By increasing the area, the contact resistance can be reduced.

[0132] Next, the insulating film 306, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor The conductive film 308d, the conductive film 310a, the conductive film 310b, the conductive film 310c, and the conductive film 310d 3, an insulating film 311a and an insulating film 311b are laminated so as to cover the conductive film 310e. 311 is formed (see FIG. 5(C)).

[0133] After the insulating film 311a is formed, the insulating film 311b is successively formed without exposing it to the air. After the insulating film 311a is formed, the flow rate of the source gas is preferably set to 1000 μm without exposing the insulating film 311a to the atmosphere. At least one of the pressure, the high frequency power, and the substrate temperature is adjusted to continuously form the insulating film 311b. By this, the concentration of impurities originating from atmospheric components at the interface between the insulating film 311a and the insulating film 311b is In addition, oxygen contained in the insulating film 311b can be reduced by The oxide semiconductor film 308b and the oxide semiconductor film 308d can be moved to the oxide semiconductor film 308c. The amount of oxygen vacancies in the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d can be reduced.

[0134] The insulating film 311a is made of a silicon oxide film placed in a processing chamber of a plasma CVD apparatus that has been evacuated to a vacuum. The substrate is kept at a temperature of 180° C. or higher and 400° C. or lower, preferably 200° C. or higher and 370° C. or lower, and processed. A raw material gas is introduced into the chamber to set the pressure in the processing chamber at 20 Pa or more and 250 Pa or less, more preferably Preferably, the pressure is 100 Pa or more and 250 Pa or less, and high frequency power is applied to the electrode provided in the processing chamber. Depending on the conditions of supply, a silicon oxide film or a silicon oxynitride film can be formed. .

[0135] As the source gas for the insulating film 311a, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of deposition gases containing silicon include silane, disilane, and trisilane. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, Nitrogen dioxide, etc.

[0136] By using the above conditions, an oxide insulating film that transmits oxygen is formed as the insulating film 311a. In addition, by providing the insulating film 311a, the insulating film 311b to be formed later can be formed. In the formation process, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film It is possible to reduce damage to 308d.

[0137] The insulating film 311a was placed in a processing chamber of a plasma CVD apparatus that was evacuated to a vacuum. The substrate is kept at 280°C or higher and 400°C or lower, and a source gas is introduced into the processing chamber. The pressure is set to 100 Pa or more and 250 Pa or less, and high frequency power is applied to the electrode installed in the treatment chamber. Depending on the conditions of supply, the insulating film 311a may be a silicon oxide film or a silicon oxynitride film. can be formed.

[0138] Under the above film formation conditions, the substrate temperature is set to the film formation temperature of the insulating film 311a, whereby silicon As a result, the insulating film 311a is dense and oxygen-permeable. It is a hard oxide insulating film, typically with a resistance to 0.5% by weight of hydrofluoric acid at 25°C. The etching rate of the silicon oxide film is 10 nm / min or less, preferably 8 nm / min or less. Alternatively, a silicon oxynitride film can be formed.

[0139] In addition, in this process, the insulating film 311a is formed while being heated. In the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d, It is possible to desorb hydrogen, water, etc. contained in the catalyst.

[0140] In addition, since heating is performed in the step of forming the insulating film 311a, the oxide semiconductor film 308a In addition, the heating time in the exposed state of the oxide semiconductor film 308b and the oxide semiconductor film 308d is short. Therefore, the amount of oxygen released from the oxide semiconductor film due to heat treatment can be reduced. In this case, the amount of oxygen vacancies in the oxide semiconductor film can be reduced.

[0141] Furthermore, by setting the pressure in the processing chamber to 100 Pa or more and 250 Pa or less, the insulating film 311 The water content in a is reduced, which reduces the variation in the electrical characteristics of transistors. At the same time, the fluctuation of the threshold voltage can be suppressed.

[0142] In addition, by setting the pressure in the processing chamber to 100 Pa or more and 250 Pa or less, the insulating film 311a During the film formation, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 30 Damage to the oxide semiconductor film 308a and the oxide semiconductor film 8d can be reduced. The amount of oxygen vacancies in the oxide semiconductor film 308b and the oxide semiconductor film 308d can be reduced. In particular, the deposition temperature of the insulating film 311a or the insulating film 311b to be formed later is increased. In the case where the temperature is higher than 220° C., the oxide semiconductor film 308 a and the oxide semiconductor film 30 8b, part of oxygen contained in the oxide semiconductor film 308d is released, and oxygen vacancies are easily formed. In order to improve the reliability of the transistor, the amount of defects in the insulating film 311b to be formed later is reduced. By using film formation conditions for reducing the amount of oxygen desorption, the amount of oxide desorption is easily reduced. The oxygen vacancies in the semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d are reduced. However, it may be difficult to maintain the pressure in the processing chamber at 100 Pa or more and 250 Pa or less. The oxide semiconductor film 308a and the oxide semiconductor film 3 311b. Even with a small amount of oxygen desorption, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor It is possible to reduce oxygen vacancies in the film 308d.

[0143] In addition, by increasing the amount of oxidizing gas to 100 times or more the amount of deposition gas containing silicon, It is possible to reduce the amount of hydrogen contained in the insulating film 311a. The amount of hydrogen mixed in the conductive film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d is Therefore, the negative shift of the threshold voltage of the transistor can be suppressed. .

[0144] The insulating film 311b is made of a silicon oxide film placed in a processing chamber of a plasma CVD apparatus that has been evacuated to a vacuum. The substrate is maintained at 180° C. or higher and 280° C. or lower, more preferably 200° C. or higher and 240° C. or lower. A raw material gas is introduced into the processing chamber to set the pressure in the processing chamber to 100 Pa or more and 250 Pa or less. More preferably, the pressure should be between 100 Pa and 200 Pa, and the pressure should be 0. 17W / cm 2 More than 0.5W / cm 2 Less than or equal to 0.25 W / cm 2 More than 0 .35W / cm 2 Silicon oxide or oxynitride is formed by supplying the following high frequency power. A silicon oxide film is formed.

[0145] As the source gas for the insulating film 311b, a deposition gas containing silicon and an oxidizing gas are used. Representative examples of deposition gases containing silicon include silane, disilane, and trisilane. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, Nitrogen dioxide, etc.

[0146] The insulating film 311b is formed under the following conditions: Supplying electric power increases the efficiency of decomposing the source gas in the plasma, and oxygen radicals increase. However, as the oxidation of the source gas progresses, the oxygen content in the insulating film 311b becomes smaller than the stoichiometric composition. However, when the substrate temperature is the deposition temperature of the insulating film 311b, Because the bond between silicon and oxygen is weak, some of the oxygen is released when heated. Oxidation that contains more oxygen than satisfies the stoichiometric composition and in which some of the oxygen is released by heating In addition, the oxide semiconductor film 308a and the oxide semiconductor film 30 8b, an insulating film 311a is provided on the oxide semiconductor film 308d. In the step of forming 311b, the insulating film 311a is The oxide semiconductor film 308b serves as a protective film for the oxide semiconductor film 308d. a. High performance while reducing damage to the oxide semiconductor film 308b and the oxide semiconductor film 308d The insulating film 311b can be formed by using high frequency power with a power density.

[0147] In addition, in the film formation conditions of the insulating film 311b, the deposition property including silicon in the oxidizing gas is By increasing the flow rate of the gas, it is possible to reduce the number of defects in the insulating film 311b. Generally speaking, the ESR measurement shows that the g value is 2.001, which is due to the dangling bond of silicon. The spin density of the signal that appears in 17 spins / cm 3 Less than 3 x 10 17 spins / cm 3 Less than or equal to 1.5×10 17 spins / cm 3 Below As a result, the reliability of the transistor can be improved. It can improve sexuality.

[0148] Next, a heat treatment is performed. The temperature of the heat treatment is typically 150° C. or higher but not higher than the substrate distortion point. Preferably, the temperature is 200° C. or higher and 450° C. or lower, and more preferably, the temperature is 300° C. or higher and 450° C. or lower. The temperature of the heat treatment is typically 300° C. or higher and 400° C. or lower, preferably By keeping the temperature between 320℃ and 370℃, there is no warping or shrinkage even in large area substrates. It is possible to reduce the amount of the defects, thereby improving the yield.

[0149] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, heat treatment can be performed at a temperature above the distortion point of the substrate for a short period of time. The processing time can be reduced.

[0150] Heat treatment is carried out in a vacuum of nitrogen, oxygen, or ultra-dry air (water content of 20 ppm or less, preferably 1 ppm). pm or less, preferably 10 ppb or less air), or rare gases (argon, helium, etc.) In addition, the above-mentioned nitrogen, oxygen, ultra-dry air, or rare gas may be mixed with hydrogen, water, or the like. It is preferable that the above is not included.

[0151] By this heat treatment, part of oxygen contained in the insulating film 311b is oxidized to the oxide semiconductor film 308a , and the oxide semiconductor film 308 b and the oxide semiconductor film 308 d are transferred to the oxide semiconductor film 308 a) reducing oxygen vacancies in the oxide semiconductor films 308b and 308d; As a result, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide The amount of oxygen vacancies in the semiconductor film 308d can be further reduced.

[0152] In addition, when the insulating film 311a and the insulating film 311b contain water, hydrogen, etc., the water, hydrogen, etc. are removed by filtration. An insulating film 313 having a locking function is formed later, and a heat treatment is performed to form the insulating film 31. Water, hydrogen, and the like contained in the insulating film 311b are absorbed in the oxide semiconductor film 308a and the oxide semiconductor The oxide semiconductor film 308a is transferred to the oxide semiconductor film 308b and the oxide semiconductor film 308d. However, the heating causes defects in the oxide semiconductor film 308b and the oxide semiconductor film 308d. This makes it possible to remove water, hydrogen, and the like contained in the insulating films 311a and 311b. This reduces the variation in the electrical characteristics of the transistors and suppresses the fluctuation in the threshold voltage. It is possible.

[0153] In addition, by forming the insulating film 311b on the insulating film 311a while heating, an oxide semiconductor Oxygen is transferred to the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d. The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d Since it is possible to reduce elemental defects, the heat treatment does not need to be performed.

[0154] In addition, the conductive film 310a, the conductive film 310b, the conductive film 310d, and the conductive film 310e are formed. At this time, the oxide semiconductor film 308a, the oxide semiconductor film 308b, The oxide semiconductor film 308d is damaged, and the oxide semiconductor film 308a and the oxide semiconductor film 3 In the back channel of the oxide semiconductor film 308a and the oxide semiconductor film 308b, (The surface opposite to the surface facing the conductive film 304a and conductive film 304c, which function as gate electrodes) However, oxygen vacancies occur on the side of the insulating film 311b. By using an oxide insulating film containing a large amount of oxygen, the back channel side is As a result, oxygen vacancies occurring in the oxide semiconductor film 308a and the oxide Since the defects contained in the semiconductor film 308b can be reduced, the reliability of the transistor can be improved. can be improved.

[0155] Note that this heat treatment may be performed after the opening 362, which will be formed later, is formed.

[0156] Next, the insulating film 311 is processed into a desired region to form an insulating film 312 and an opening 362. The insulating film 311 and the opening 362 are formed in a desired region by forming a fourth pattern. A mask is formed by etching, and the area not covered by the mask is etched. The conductive film 304b can be formed by the above steps (see FIG. 6A). This part of the insulating film 311 is also etched.

[0157] Note that the opening 362 is formed so that the surface of the oxide semiconductor film 308d is exposed. The opening 362 can be formed by, for example, dry etching. However, the method for forming the opening 362 is not limited to this, and may be a wet etching method, Alternatively, a combination of dry etching and wet etching may be used. .

[0158] Next, the insulating film 313 is formed over the insulating film 306, the insulating film 312, and the oxide semiconductor film 308d. (See FIG. 6(B)).

[0159] The insulating film 313 is made of a material that is free of impurities from the outside, such as oxygen, hydrogen, water, alkali metals, It is preferable to use a material that prevents an alkaline earth metal or the like from diffusing into the oxide semiconductor film. , and preferably contains hydrogen, typically an inorganic insulating material containing nitrogen, such as a nitride The insulating film 313 may be formed by using, for example, a CVD method. It is possible.

[0160] The insulating film 313 is resistant to external impurities such as water, alkali metals, alkaline earth metals, etc. The film is formed of a material that prevents diffusion of hydrogen into the oxide semiconductor film and further contains hydrogen. Therefore, when hydrogen in the insulating film 313 diffuses into the oxide semiconductor film 308d, the oxide semiconductor In the film 308d, hydrogen combines with oxygen to generate electrons, which are carriers. The oxide semiconductor film 308d has high conductivity and becomes the light-transmitting conductive film 308c.

[0161] In addition, the silicon nitride film is preferably formed at a high temperature in order to enhance blocking properties. The substrate temperature is preferably 100° C. or higher and 400° C. or lower, more preferably 300° C. or higher and 400° C. or lower. It is preferable to form the film by heating at a temperature of 0.1 ° C. or less. Oxygen is released from the oxide semiconductor used for the semiconductor film 308a and the oxide semiconductor film 308b. In some cases, the carrier concentration may increase. The temperature.

[0162] Next, the insulating film 313, the insulating film 312, the insulating film 306, and the insulating film 305 are applied to desired regions. By this process, an insulating film 314, and openings 364a and 364b are formed. The insulating film 314, the openings 364a, and the openings 364b are formed in a desired region by a fifth patterning. The mask is formed by etching the area not covered by the mask. (See FIG. 6(C)).

[0163] The opening 364a is formed so that the surfaces of the conductive film 304a and the conductive film 310c are exposed. The opening 364b is formed so as to expose the conductive film 310e.

[0164] The openings 364a and 364b can be formed by, for example, dry etching. However, as a method for forming the openings 364a and 364b, However, the method is not limited thereto, and may be a wet etching method or a combination of a dry etching method and a wet etching method. A forming method combining this with etching methods may also be used.

[0165] By providing the opening 364a in this manner, the opening 364a and the insulating film to be formed later are This can improve the coverage of the films on the insulating film 305, the insulating film 306, and the conductive film 310c.

[0166] Next, a light-transmitting layer is formed on the insulating film 314 so as to cover the openings 364a and 364b. A conductive film 315 is formed (see FIG. 7A).

[0167] The light-transmitting conductive film 315 is formed by, for example, a sputtering method. This can be done.

[0168] Next, the light-transmitting conductive film 315 is processed into a desired region to form a light-transmitting conductive film. A conductive film 316a having a light-transmitting property and a conductive film 316b having a light-transmitting property are formed. The formation of the conductive film 316a and the conductive film 316b having light transmitting properties is performed in a desired region by the sixth patterning. The mask is formed by etching the area not covered by the mask. (See FIG. 7(B)).

[0169] Through the above steps, a pixel portion having a transistor and a driver circuit portion are formed on the substrate 302. In the manufacturing process shown in this embodiment, the first to sixth patterned This means that transistors and capacitors can be formed simultaneously using six masks. do.

[0170] Note that in this embodiment, hydrogen contained in the insulating film 314 is diffused into the oxide semiconductor film 308d. The oxide semiconductor film 308d was dispersed to increase the conductivity. The oxide semiconductor film 308b is covered with a mask, and impurities, typically water, are added to the oxide semiconductor film 308d. Boron, phosphorus, tin, antimony, rare gas elements, alkali metals, alkaline earth metals, etc. The oxide semiconductor film 308d may be doped to increase the conductivity. The method of adding hydrogen, boron, phosphorus, tin, antimony, rare gas elements, etc. to iodine is On the other hand, the oxide semiconductor film 308d is doped with an alkali metal As a method for adding an alkaline earth metal or the like, a solution containing the impurity is added to the oxide semiconductor film 3 There is a way to expose it to 08d.

[0171] In this embodiment, only the opening 364a has a stepped shape in part, but this is not limiting. When the insulating film 311 is processed, the insulating film 311 in the region where the opening 364b is to be formed is also In the formation of the opening after the formation of the insulating film 313, the opening has a stepped shape in part. A portion 364b may be formed.

[0172] Next, the element portion provided on the substrate 342 provided opposite the substrate 302 will be described below. Here, the element portion provided on the substrate 342 is a substrate 342. and the alignment film 352.

[0173] First, a substrate 342 is prepared. The substrate 342 is made of the same material as that of the substrate 302. Next, a light-shielding film 344 and a colored film 346 are formed on the substrate 342 (FIG. 8(A) )reference).

[0174] The light-shielding film 344 and the colored film 346 are formed of various materials by a printing method, an ink-jet method, They are formed at desired positions by an etching method using photolithography technology.

[0175] Next, an insulating film 348 is formed on the light-shielding film 344 and the colored film 346 (see FIG. 8(B)). ).

[0176] The insulating film 348 is made of an organic insulating material such as an acrylic resin, an epoxy resin, or a polyimide. By forming the insulating film 348, for example, the colored film 34 It is possible to prevent impurities contained in the liquid crystal layer 6 from diffusing to the liquid crystal layer 320 side. However, the insulating film 348 is not necessarily required, and a structure in which the insulating film 348 is not formed may be used. Good too.

[0177] Next, a conductive film 350 is formed over the insulating film 348 (see FIG. 8C). For this purpose, the materials shown for the light-transmitting conductive film 315 can be used.

[0178] Through the above steps, the structure formed on the substrate 342 can be formed.

[0179] Next, the insulating film 31 formed on the substrate 302 and the substrate 342, more specifically, on the substrate 302, 4. A light-transmitting conductive film 316a, a light-transmitting conductive film 316b, and a substrate 342 An alignment film 318 and an alignment film 352 are formed on the formed conductive film 350. The alignment film 352 can be formed by using a rubbing method, a photoalignment method, or the like. Then, the liquid crystal layer 320 is formed between the substrate 302 and the substrate 342. The method may be a dispenser method (dropping method), or a method in which the substrate 302 and the substrate 342 are bonded together. Alternatively, a liquid crystal injection method can be used in which liquid crystal is injected using capillary action.

[0180] Through the above steps, the liquid crystal display device shown in FIG. 3 can be manufactured.

[0181] In addition, various films such as metal films, semiconductor films, and inorganic insulating films disclosed in the embodiments are sputtered. The thin film can be formed by a deposition method or a plasma CVD method, but other methods, such as thermal CVD, are also possible. The film may be formed by a chemical vapor deposition (Chemical Vapor Deposition) method. As an example of the CVD method, MOCVD (Metal Organic Chemical Vapor Deposition) por Deposition method and ALD (Atomic Layer Deposition) method. tion) method may also be used.

[0182] Thermal CVD is a film formation method that does not use plasma, so defects can occur due to plasma damage. This has the advantage that no additional steps are required.

[0183] In the thermal CVD method, the source gas and the oxidizing agent are fed into the chamber at the same time, and the chamber is heated to atmospheric pressure. Alternatively, a film is formed by reacting the reactants near or on the substrate under reduced pressure and depositing the reactants on the substrate. You may go.

[0184] In addition, in the ALD method, the pressure inside the chamber is set at atmospheric pressure or reduced pressure, and the source gas for the reaction is The gases may be introduced into the chamber in sequence, and the film may be formed by repeating the gas introduction sequence. For example, by switching each switching valve (also called high-speed valve), two or more types of The above source gases are supplied to the chamber in order, and the first source gas is supplied to the chamber in order to prevent the mixture of the source gases. An inert gas (such as argon or nitrogen) is introduced simultaneously with or after the raw material gas. The second source gas is introduced. When an inert gas is introduced at the same time, the inert gas is It acts as a carrier gas, and even if an inert gas is introduced at the same time as the second source gas is introduced, In addition, the first source gas is discharged by evacuation instead of introducing an inert gas. After that, a second source gas may be introduced. The first source gas is adsorbed on the surface of the substrate to form a first layer. The first layer is deposited on the second layer by reacting with the second source gas introduced later. This process is repeated several times while controlling the gas introduction sequence until the desired thickness is reached. By doing so, a thin film with excellent step coverage can be formed. The thickness of the thin film is determined by the gas introduction. The thickness can be precisely adjusted by changing the number of times the sequence is repeated. This is suitable for producing miniature FETs.

[0185] Thermal CVD methods such as MOCVD and ALD are disclosed in the embodiments described above. It is possible to form various films such as metal films, semiconductor films, and inorganic insulating films. For example, In- When forming a Ga-Zn-O film, trimethylindium, trimethylgallium, and The chemical formula for trimethylindium is In(CH3)3. The chemical formula for trimethylgallium is Ga(CH3)3. The chemical formula for zinc is Zn(CH3)2. Instead of trimethylgallium, triethylgallium (chemical formula Ga(C2H5)3) is used. Alternatively, diethylzinc (chemical formula Zn(C2H5)2) can be used instead of dimethylzinc. It is also possible.

[0186] For example, when forming a hafnium oxide film using a film forming apparatus that uses ALD, the solvent and a liquid containing a hafnium precursor compound (hafnium alkoxide solution, typically tetra The raw material gas is vaporized with tetramethyl tert-butyl amide hafnium (TDMAH) as an oxidizing agent. Two types of gases are used: tetrakisdimethylamidohafnium (TDA) and ozone (O3). The chemical formula is Hf[N(CH3)2]4. Other material liquids include tetrakis(ethoxycarbonyl) (ethylmethylamido) hafnium.

[0187] For example, when forming an aluminum oxide film using an ALD deposition system, A liquid containing a catalyst and an aluminum precursor compound (e.g., trimethylaluminum (TMA)) is added. Two types of gases are used: vaporized source gas and H2O as an oxidizing agent. The chemical formula for aluminum is Al(CH3)3. Other liquid materials include Tris( Dimethylamido)aluminum, triisobutylaluminum, aluminum tris(2 ,2,6,6-tetramethyl-3,5-heptanedionate).

[0188] For example, when forming a silicon oxide film using a deposition system that uses ALD, Chlorodisilane is adsorbed onto the surface to be coated, the chlorine contained in the adsorbed matter is removed, and the oxidizing gas (O 2. Nitrous oxide (NO) radicals are supplied to react with the adsorbed material.

[0189] For example, when forming a tungsten film using an ALD deposition system, WF6 The initial tungsten film was formed by repeatedly introducing B2H6 gas and WF 6 gas and H2 gas are introduced simultaneously to form a tungsten film. Alternatively, SiH4 gas may be used.

[0190] For example, an oxide semiconductor film, such as In-Ga-Zn- When forming an O film, In(CH3)3 gas and O3 gas are introduced in sequence. Then, Ga(CH3)3 gas and O3 gas are introduced simultaneously to form a GaO layer. Then, Zn(CH3)2 gas and O3 gas are introduced simultaneously to form a ZnO layer. The order of these layers is not limited to this example. A mixed compound layer such as an aO layer, an In-Zn-O layer, or a Ga-Zn-O layer may be formed. In addition, instead of O3 gas, H2O gas obtained by bubbling with an inert gas such as Ar was used. However, it is preferable to use O3 gas that does not contain H. In(CH3)3 gas is also used. Alternatively, In(C2H5)3 gas may be used. Ga(C2H5)3 gas may be used instead of In(CH3)3 gas. Alternatively, n(C2H5)3 gas may be used, or Zn(CH3)2 gas may be used.

[0191] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do.

[0192] <Variation 1> A modification of the opening 364a in the first embodiment will be described with reference to FIG. 3, AB is a cross-sectional view of the drive circuit portion, and CD is a cross-sectional view of the pixel portion.

[0193] In FIG. 3, in the opening 364a, the light-transmitting conductive film 316a is formed on the conductive film 304b. 9, only the light-transmitting conductive film 316a is provided in the opening 364c. is in contact not only with the conductive film 304b but also with the substrate 302. By increasing the contact area between the light-transmitting conductive film 316a and the conductive film 304b, Resistance can be reduced.

[0194] In addition, in the region 370 surrounded by the broken line in FIG. 9, an insulating film 304b is provided covering one end of the conductive film 304b. The conductive film 310c, the conductive film 304b and the conductive film 310c on the insulating film (here, the gate insulating film) are 10c) is electrically connected to the conductive film (here, the conductive film 316a having light-transmitting properties). The structure described above can also be applied to the terminals of semiconductor devices, and the contact resistance can be reduced in a similar manner. can be done.

[0195] <Variation 2> Another modification of the opening 364a in the first embodiment will be described with reference to FIG. In FIG. 10, AB is a cross-sectional view of the driving circuit portion, and CD is a cross-sectional view of the pixel portion, similar to FIG. It is.

[0196] FIG. 10 shows a process for etching the insulating film 314, the insulating film 312, the insulating film 306, and the insulating film 305 all at once. This is different from the cross-sectional view shown in FIG. 3 in that an opening is formed by dividing the opening.

[0197] Here, a method for manufacturing the liquid crystal display device shown in FIG. 10 will be described with reference to FIGS. This will be explained using 12.

[0198] As in the first embodiment, the steps of FIG. 4 to FIG. 5(C) are carried out to obtain a semiconductor device as shown in FIG. 11(A). A conductive film 304a, a conductive film 304b, and a conductive film 304c functioning as gate electrodes are formed on a substrate 302. 304c, the insulating film 305 and the insulating film 306 which function as gate insulating films, and an oxide semiconductor film 308a, an oxide semiconductor film 308b, an oxide semiconductor film 308d, a conductive film 310a, and a conductive film 310b, a conductive film 310c, a conductive film 310d, a conductive film 310e, and an insulating film 311 are formed. In this process, first to third patterning are performed, The conductive film 304a, the conductive film 304b, the conductive film 304c, the oxide semiconductor film 308a, and the oxide The oxide semiconductor film 308b, the oxide semiconductor film 308d, the conductive film 310a, the conductive film 310b, A conductive film 310c, a conductive film 310d, and a conductive film 310e are formed.

[0199] Next, the insulating film 311 is processed into a desired region to form an insulating film 312 and an opening 362. The insulating film 311 and the opening 362 are formed in a desired region by forming a fourth patterning. The mask is formed by etching the area not covered by the mask. This can be achieved (see FIG. 11(B)).

[0200] Next, the insulating film 313 is formed over the insulating film 312 and the oxide semiconductor film 308d (FIG. 11 (See (C)).

[0201] Next, the insulating film 313, the insulating film 312, the insulating film 306, and the insulating film 305 are applied to desired regions. By this process, an insulating film 314, and openings 364a and 364b are formed. The insulating film 314, the openings 364a, and the openings 364b are formed in a desired region by a fifth patterning. The mask is formed by etching the area not covered by the mask. This can be achieved (see FIG. 12(A)).

[0202] By providing the opening 364a in this manner, the opening 364a and the insulating film 3 05, the coverage of the film on the insulating film 306 and the conductive film 310c can be improved.

[0203] Next, a light-transmitting layer is formed on the insulating film 314 so as to cover the openings 364a and 364b. A conductive film 315 is formed (see FIG. 12B).

[0204] Next, the light-transmitting conductive film 315 is processed into a desired region to form a light-transmitting conductive film. A conductive film 316a having a light-transmitting property and a conductive film 316b having a light-transmitting property are formed. The formation of the conductive film 316a and the conductive film 316b having light transmitting properties is performed in a desired region by the sixth patterning. The mask is formed by etching the area not covered by the mask. (See FIG. 12(C)).

[0205] Through the above steps, a pixel portion having a transistor and a driver circuit portion are formed on the substrate 302. In the manufacturing process shown in this embodiment, the first to sixth patterned This means that transistors and capacitors can be formed simultaneously using six masks. do.

[0206] <Variation 3> Here, a modification of the liquid crystal display device shown in the first embodiment will be described with reference to FIG. In FIG. 13, AB is a cross-sectional view of the drive circuit section, and CD is a cross-sectional view of the pixel section, similar to FIG. FIG.

[0207] FIG. 13 is different from the cross-sectional view shown in FIG. 3 in that a planarizing film 317 is provided under an alignment film 318. .

[0208] The planarization film 317 is a light-transmitting conductive film 316 that functions as at least a pixel electrode. The organic resin film is filled in the recesses of the conductive film 316b having light transmitting properties. The conductive film 3 has a light-transmitting property, that is, a region through which the backlight of the liquid crystal display device passes. The recess provided at the opening of 08c is filled with a planarizing film 317, so that the area where the alignment film is to be formed is That is, the unevenness of the light-transmitting conductive film 316b can be reduced. It is possible to reduce the unevenness of the alignment film 318. The depth of the recess is determined based on the thickness of the insulating film 312. is equivalent to.

[0209] The planarization film 317 is preferably light-transmitting. For example, the planarization film 317 may be a color filter or a black matrix. For example, the planarization film 317 may have a function of a color filter. In the case where the pixel count is 1, for example, red pixels, blue pixels, and green pixels, A colored flattening film 317 may be formed.

[0210] The planarization film 317 is made of an organic resin such as acrylic resin, polyimide, or epoxy resin. The thickness of the planarization film 317 is preferably equal to or greater than the thickness of the insulating film 312. The thickness is set to 1500 nm or less, and preferably to 1000 nm or less than the thickness of the insulating film 312. By making the thickness of the film 317 equal to or greater than the thickness of the insulating film 312, the light-transmitting conductive film 316b The recesses in the region can be filled with a planarizing film 317, and an alignment film 318 is formed in the region. If the thickness of the planarizing film 317 is large, the unevenness of the liquid crystal layer 320 can be reduced. When controlling the orientation, a voltage is applied to the conductive film 316b having a light transmitting property and functioning as a pixel electrode. The voltage becomes large and the power consumption becomes high, so the thickness of the flattening film 317 is set to 1500. nm or less is preferable.

[0211] By forming the planarization film 317 using an organic resin, it is possible to form a film that functions at least as a pixel electrode. The recesses of the light-transmitting conductive film 316b can be filled with the planarizing film 317. It is possible to reduce uneven alignment of the liquid crystal molecules that make up the liquid crystal layer 320.

[0212] The planarization film 317 can be formed by a method such as spin coating, dip coating, slit coating, or ink coating. The planarization film 317 is formed by using a wet method such as an ink jet method or a printing method. Therefore, the planarization film 317 having a flat surface can be formed without being affected by the unevenness of the region where the film is to be formed. The planarization film 317 can be formed by a method such as spin coating, dip coating, or slit coating. In the case of using the method, after applying the composition, a mask by the seventh patterning is applied to the desired area. The area not covered by the mask is then etched to form a planarizing film 317. can be formed.

[0213] In the liquid crystal display device according to this modification, a light-transmitting conductive film 316 which functions as a pixel electrode is Since the planarization film 317 is provided on the conductive film 316b, the planarization film 317 is formed in the recess of the conductive film 316b having light transmitting properties. 17 is filled, and further, the step on the surface of the planarization film 317 is small. The surface irregularities of the alignment film 318 provided on the alignment layer 317 are reduced, reducing the alignment irregularities of the liquid crystal. As a result, display defects in the liquid crystal display device can be reduced.

[0214] <Modification 4> Here, a modification of the liquid crystal display device shown in the first embodiment will be described with reference to FIG. In FIG. 14, AB is a cross-sectional view of the drive circuit section, and CD is a cross-sectional view of the pixel section, similar to FIG. FIG.

[0215] FIG. 14 shows the difference between the thickness of the alignment film 318 and the unevenness of the pixel portion shown in FIG. This differs from the cross-sectional view.

[0216] In this embodiment, the alignment film 318 on the light-transmitting conductive film 316b in the pixel portion is an insulating film. The recess 360 of the conductive film 316b having light transmission, which is caused by the insulating film 312, is completely filled. However, the present invention is not limited to this. The alignment film 318 may be formed gently and the recess 360 may be partially filled. The configuration may be such that:

[0217] <Variation 5> A modified example of a liquid crystal display device using a liquid crystal element in the pixel 301 will be described. In the liquid crystal display devices shown in FIGS. 10, 13, and 14, the light-transmitting conductive film 308c is in contact with the insulating film 314, but may be in contact with the insulating film 305. In this case, since there is no need to provide the opening 362 as shown in FIG. 16a, and the step on the surface of the light-transmitting conductive film 316b can be reduced. Therefore, it is possible to reduce the alignment disorder of the liquid crystal material contained in the liquid crystal layer 320. Thus, a liquid crystal display device with high contrast can be manufactured.

[0218] In order to obtain such a structure, in FIG. 4B, the oxide semiconductor film 307 is formed. Before this, the insulating film 306 may be selectively etched to expose a part of the insulating film 305. stomach.

[0219] <Variation 6> Here, a modification of the liquid crystal display device shown in the first embodiment will be described with reference to FIGS. In FIG. 15, AB shows a cross-sectional view of the driving circuit section, and CD shows a cross-sectional view of the pixel section. In addition, the first embodiment will be used here, but this modification will be used for each modification as appropriate. can be applied.

[0220] The liquid crystal display device shown in FIG. 15 has a channel The difference is that a protection transistor is used.

[0221] In the driver circuit portion, a conductive film 304a functions as a gate electrode, and a gate insulating film The insulating film 305 and the insulating film 306 functioning as a channel region are formed in the oxide semiconductor film 30. 8a, the conductive film 310a and the conductive film 310b functioning as a source electrode and a drain electrode, After the oxide semiconductor film 308a is formed, the conductive film 310a is Before the conductive film 310b is formed, an insulating film 312 that functions as a channel protective film is provided. Moreover, an insulating film 314 is provided as a protective film on the conductive film 310a, the conductive film 310b, and the conductive film 310c. It is established as such.

[0222] In the pixel portion, a conductive film 304c functions as a gate electrode, and a gate insulating film The insulating film 305 and the insulating film 306 are formed on the gate insulating film. a conductive film 310 serving as a source electrode and a drain electrode; d. The conductive film 310e constitutes the transistor 103. Formation of the oxide semiconductor film 308b After the formation of the conductive film 310d and the conductive film 310e, an insulating film that functions as a channel protective film is formed. A film 312 is provided on the conductive film 310d and the conductive film 310e. An insulating film 314 is provided on the conductive film 310d and the conductive film 310e. It is provided as a protective film.

[0223] In addition, a light-transmitting conductive film 316b functioning as a pixel electrode is provided on the insulating film 314. In the opening, the conductive film 310e is connected.

[0224] In addition, a light-transmitting conductive film 308c functioning as one electrode and a dielectric film The insulating film 314 serving as the other electrode and the light-transmitting conductive film 316b serving as the other electrode form a capacitor. The element 105 is formed.

[0225] In the driving circuit section, a conductive film formed simultaneously with the conductive film 304a and the conductive film 304c is The conductive film 304b is the same as the conductive film 310a, the conductive film 310b, the conductive film 310d, and the conductive film 310e. The conductive film 310c formed at the same time is a conductive film 316b having light-transmitting properties. The connection is made through a light-transmitting conductive film 316a.

[0226] In this modification, the conductive film 310a, the conductive film 310b, the conductive film 310d, and the conductive film 31 When etching the insulating film 308e, the oxide semiconductor film 308a and the oxide semiconductor film 308b are 12, the conductive film 310a, the conductive film 310b, the conductive film 310d, and the conductive film 3 The oxide semiconductor film 308a and the oxide semiconductor film 308e are formed by etching. b is not damaged. Furthermore, the insulating film 312 is more oxidized than the oxygen that satisfies the stoichiometric composition. The insulating film 312 is formed of an oxide insulating film containing a large amount of oxygen. A part of the oxide semiconductor film is transferred to the oxide semiconductor film 308a and the oxide semiconductor film 308b. By using the oxide semiconductor film 308a, the amount of oxygen vacancies in the oxide semiconductor film 308b can be reduced.

[0227] A method for manufacturing an element portion provided on a substrate 302 in a liquid crystal display device shown in FIG. This will be explained using Figures 4, 16, and 17.

[0228] As in the first embodiment, a gate electrode is formed on the substrate 302 through the process shown in FIG. The conductive film 304a, the conductive film 304b, and the conductive film 304c function as a gate insulating film. The oxide semiconductor film 305, the insulating film 306, the oxide semiconductor film 308a, the oxide semiconductor film 308b, In this process, the first patterning and the second patterning are performed. The conductive film 304a, the conductive film 304b, the conductive film 304c, and the oxide film 304b are patterned. The oxide semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d are formed. .

[0229] Next, similarly to the first embodiment, the insulating film 311a and the insulating film 311b are laminated. 11 is formed (see FIG. 16(A)).

[0230] Thereafter, in the same manner as in the first embodiment, a heat treatment is performed to remove some of the oxygen contained in the insulating film 311. The oxide semiconductor film 308a and the oxide semiconductor film 308b are transferred to the oxide semiconductor film 30 8a, the amount of oxygen vacancies in the oxide semiconductor film 308b can be reduced.

[0231] Next, the insulating film 311 is processed into desired regions to form the oxide semiconductor film 308a and the oxide An insulating film 312 is formed over the semiconductor film 308b (see FIG. 16B). When the insulating film 306 is made of the same material as the insulating film 312, a part of the insulating film 306 may be etched. The region that is etched and covered with the oxide semiconductor film 308a and the oxide semiconductor film 308b The insulating film 306 and the insulating film 312 are formed by forming a third pattern in a desired region. forming a mask by etching and then etching the areas not covered by the mask; It can be formed by:

[0232] Next, the insulating film 305, the insulating film 306, the oxide semiconductor film 308a, and the oxide semiconductor film 308 After forming a conductive film on the conductive film 3b, the conductive film 310a and the conductive film 3b are formed by the same process as in the first embodiment. 10b, a conductive film 310c, a conductive film 310d, and a conductive film 310e are formed (see FIG. 16(C)). In addition, the conductive film 310a, the conductive film 310b, the conductive film 310c, the conductive film 310d, The film 310e is formed by forming a mask by a fourth patterning in a desired region. It can be formed by etching the areas not covered by the mask.

[0233] Next, the insulating film 305, the insulating film 312, the oxide semiconductor film 308d, the conductive film 310a, and the conductive An insulating film 313 is formed on the film 310b, the conductive film 310c, the conductive film 310d, and the conductive film 310e. (See FIG. 17(A)).

[0234] Next, in the same manner as in the second modification, the insulating film 313 is processed into a desired region to form an insulating film 314. , and openings 384a and 384b are formed. The opening 384a and the opening 384b are formed by forming a mask by the fifth patterning in a desired area. The regions not covered by the mask can be etched (FIG. 17). (See (B)).

[0235] By providing the opening 384a in this manner, the conductive film 304b, the insulating film 305, and the conductive film 3 The coverage of the film on 10c can be improved.

[0236] Next, in the same manner as in the first embodiment, the insulating film 3 is formed so as to cover the openings 384a and 384b. A light-transmitting conductive film is formed on the substrate 14. Next, the light-transmitting conductive film is By processing, a light-transmitting conductive film 316a and a light-transmitting conductive film 316b are formed. Note that the light-transmitting conductive film 316a and the light-transmitting conductive film 316b are formed as follows: A mask is formed in a desired region by a sixth patterning, and the part not covered by the mask is removed. It can be formed by etching the area (see FIG. 17(C)).

[0237] Through the above steps, a pixel portion having a transistor and a driver circuit portion are formed on the substrate 302. In the manufacturing process shown in this embodiment, the first to sixth patterned This means that transistors and capacitors can be formed simultaneously using six masks. do.

[0238] <Variation 7> In this embodiment and the modified example, a pair of electrodes constituting the capacitor element 105 is made of a light-transmitting material. The conductive film 308c having a light-transmitting property and the conductive film 316b having a light-transmitting property are used. As shown in FIGS. 40 and 41, a light-transmitting insulating film 312 and a light-transmitting insulating film 314 are provided between the insulating film 312 and the insulating film 314. A conductive film 325 having a light-transmitting property is formed over the insulating film 314, and a light-transmitting conductive film 316d is formed over the insulating film 314. The conductive film 325 having a light-transmitting property and the conductive film 316d are used to form the capacitor 105. The electrodes can be used as a pair.

[0239] Furthermore, on the insulating film 312, an organic insulating film such as an acrylic resin, an epoxy resin, or a polyimide is applied. Since an organic insulating film made of an acrylic resin or the like has high flatness, it is possible to provide a light-transmitting film. It is possible to reduce the step on the surface of the conductive film 316a. It is possible to reduce the alignment disorder of the liquid crystal material that is generated by the liquid crystal display. A device can be fabricated.

[0240] As shown in FIG. 42A, the conductive film 304b and the conductive film 310c are in contact with each other, and the insulating film 3 A planarizing film 317 is formed on the insulating film 314, and openings are formed in the planarizing film 317, the insulating film 314, and the insulating film 312. and forming a light-transmitting conductive film 326 that is in contact with the conductive film 310c through the opening. In addition, an insulating film 324 is formed over the planarizing film 317 and the light-transmitting conductive film 326. Furthermore, as shown in FIG. 42(B), a flattening film 317 is formed on the insulating film 314. A light-transmitting conductive film 325 is formed on the planarizing film 317. An insulating film 324 is formed over a conductive film 325 having a light-transmitting property. A conductive film 316d is formed, and the light-transmitting conductive film 325 and the light-transmitting conductive film 316 d may be used as a pair of electrodes forming the capacitor 105. The insulating film 314 may be made of a material similar to that of the insulating film 314 .

[0241] (Embodiment 2) In this embodiment, modified examples which can be applied to the transistor described in Embodiment 1 will be described. Reveal.

[0242] <Modification 1, Regarding the Undercoat Insulating Film> In the transistors 102 and 103 described in Embodiment 1, A base insulating film is formed between the substrate 302 and the conductive film 304a, the conductive film 304b, and the conductive film 304c. The base insulating film can be made of silicon oxide, silicon oxynitride, or nitride. Silicon oxide, silicon nitride, gallium oxide, hafnium oxide, yttrium oxide, Examples of materials for the base insulating film include aluminum nitride and aluminum oxynitride. Silicon, gallium oxide, hafnium oxide, yttrium oxide, aluminum oxide, etc. By this, impurities, typically alkali metals, water, hydrogen, etc., are removed from the substrate 302. Therefore, the diffusion of the oxygen into the oxide semiconductor film 308a and the oxide semiconductor film 308b can be suppressed.

[0243] The base insulating film can be formed by a sputtering method, a CVD method, or the like.

[0244] <Modification 2: Gate insulating film> In the transistors 102 and 103 described in Embodiment 1, In this case, the laminated structure of the insulating film functioning as the gate insulating film can be modified. The transistor 103 will be used for explanation.

[0245] As shown in FIG. 18A, the gate insulating film is made up of an insulating film 305 and an insulating film 306. The layers are stacked in order starting from the conductive film 304c that functions as an electrode.

[0246] By providing the insulating film 305 made of a nitride insulating film on the conductive film 304c side, the conductive film 3 Impurities from 04c, typically hydrogen, nitrogen, alkali metals, or alkaline earth metals etc. can be prevented from moving to the oxide semiconductor film 308b.

[0247] In addition, the insulating film 306 formed of an oxide insulating film is provided on the oxide semiconductor film 308b side. As a result, the density of defect states at the interface between the insulating film 306 and the oxide semiconductor film 308b can be reduced. As a result, a transistor with little deterioration in electrical characteristics can be obtained. Note that the insulating film 306 is formed of a material having a stoichiometric composition containing oxygen, similar to the insulating film 312b. When the oxide insulating film containing as much oxygen as possible is used, the insulating film 306 and the oxide semiconductor film This is more preferable because it is possible to further reduce the defect state density at the 308b interface. It is nice.

[0248] As shown in FIG. 18A, the insulating film 305 is a nitride insulating film 305 having few defects. a and a nitride insulating film 305b having high hydrogen blocking properties are arranged in this order from the conductive film 304c side. The insulating film 305 may be a nitride insulating film having few defects. By providing the film 305a, the dielectric strength of the gate insulating film can be improved. By providing the nitride insulating film 305b having a high hydrogen blocking property, the conductive film 304c and the nitride insulating film 305b can be prevented from being damaged. Therefore, hydrogen can be prevented from moving from the oxide semiconductor film 305a to the oxide semiconductor film 308b. Cut.

[0249] An example of a method for producing the nitride insulating film 305a and the nitride insulating film 305b shown in FIG. First, a mixture of silane, nitrogen, and ammonia was used as the source gas. A silicon nitride film with few defects is formed as a nitride insulating film 305a by the plasma CVD method. Next, the source gas is switched to a mixture of silane and nitrogen, and the hydrogen concentration is reduced. The silicon nitride film is a nitride insulating film 305b that is not easily oxidized and can block hydrogen. This method of formation results in a film with few defects and excellent hydrogen blocking properties. In the present invention, a gate insulating film having a nitride insulating film and a gate insulating film having the nitride insulating film are stacked.

[0250] Alternatively, as shown in FIG. 18B, the insulating film 305 has a high impurity blocking property. The nitride insulating film 305c, the nitride insulating film 305a having few defects, and the hydrogen blocking property The nitride insulating film 305b and the conductive film 304c are laminated in this order. The insulating film 305 is a nitride insulating film 305c having high impurity blocking properties. By providing the conductive film 304c, impurities, typically hydrogen, nitrogen, alkali metals, etc., can be prevented from being generated. Alternatively, the alkaline earth metal or the like can be prevented from moving to the oxide semiconductor film 308b. do.

[0251] The nitride insulating film 305a, the nitride insulating film 305b, and the nitride insulating film 30 shown in FIG. An example of the method for producing 5c ​​is shown below. First, a mixed gas of silane, nitrogen, and ammonia is Nitriding with high impurity blocking properties was achieved by the plasma CVD method using nitrogen as the raw material gas. The silicon film is formed as a nitride insulating film 305c. Next, the flow rate of ammonia is increased. By this, a silicon nitride film with few defects is formed as the nitride insulating film 305a. The source gas is switched to a mixture of silane and nitrogen, and hydrogen concentration is low and hydrogen is not blown. A silicon nitride film capable of rocking is formed as the nitride insulating film 305b. By using such a formation method, a nitride insulating film having few defects and a blocking property against impurities can be obtained. An insulating film 305 can be formed by laminating an insulating film.

[0252] <Modification 3: Pair of Electrodes> In the liquid crystal display device shown in Embodiment 1, the conductive film 310a, the conductive film 310b, the conductive film Materials that can be used for the conductive film 310c, the conductive film 310d, and the conductive film 310e will now be described. Here, the transistor 103 is used for description.

[0253] The conductive films 310d and 310e provided in the transistor 103 described in Embodiment 1 As the metal, tungsten, titanium, aluminum, copper, molybdenum, chromium, or tantalum It is preferable to use a conductive material that easily reacts with oxygen, such as a simple metal or an alloy. The oxygen contained in the oxide semiconductor film 308b and the oxygen contained in the conductive films 310d and 310e A reaction with the conductive material occurs, and a region with many oxygen vacancies is formed in the oxide semiconductor film 308b. In addition, a conductive material for forming the conductive film 310d and the conductive film 310e is provided on the oxide semiconductor film 308b. As a result, as shown in Figure 19, the oxide In the semiconductor film 308b, a low resistance layer is formed in the vicinity of the region in contact with the conductive film 310d and the conductive film 310e. The low resistance region 334a and the low resistance region 334b ​​are formed. 34b is in contact with the conductive film 310d and the conductive film 310e, and is also in contact with the insulating film 306 and the conductive film 310 The low resistance region 334a and the low resistance region 334b ​​are formed between the conductive film 310d and the conductive film 310e. Since the oxide semiconductor film 308b has high electrical conductivity, the contact resistance between the oxide semiconductor film 308b and the conductive film 310d and the conductive film 310e is low. It is possible to reduce the resistance and increase the on-state current of the transistor. .

[0254] In addition, the conductive film 310d and the conductive film 310e are formed by using the conductive material that easily reacts with oxygen and a nitride. As a laminated structure with conductive materials that do not easily react with oxygen, such as titanium, tantalum nitride, and ruthenium By forming such a layered structure, the conductive film 310d, the conductive film 310e, and the oxide semiconductor At the interface with the conductive film 308b, the conductive films 310d and 310e can be prevented from being oxidized. It is possible to prevent the conductive films 310d and 310e from becoming high in resistance.

[0255] <Modification 4: Oxide Semiconductor Film> In the method for manufacturing the transistors 102 and 103 described in Embodiment 1, After forming the conductive film 310a, the conductive film 310b, the conductive film 310d, and the conductive film 310e, an oxide The semiconductor film 308a and the oxide semiconductor film 308b are exposed to plasma generated in an oxygen atmosphere. Oxygen can be supplied to the oxide semiconductor film 308a and the oxide semiconductor film 308b. The atmosphere may be oxygen, ozone, nitrous oxide, nitrogen dioxide, or the like. In the plasma processing, the plasma generated without applying a bias to the substrate 302 side It is preferable to expose the oxide semiconductor film 308a and the oxide semiconductor film 308b to the infrared ray. , the oxide semiconductor film 308a and the oxide semiconductor film 308b are not damaged and oxygen is not supplied to them. The oxide semiconductor film 308a and the oxide semiconductor film 308b can be supplied with the oxide semiconductor film 308a. In addition, the amount of oxygen vacancies in the oxide semiconductor film 308 can be reduced by the etching treatment. a) Impurities remaining on the surface of the oxide semiconductor film 308b, for example, halogens such as fluorine and chlorine, It is possible to remove such substances.

[0256] <Modification 5: Regarding Oxide Semiconductor Film> In the transistors 102 and 103 described in Embodiment 1, In this embodiment, the oxide semiconductor film is formed to have a stacked structure. He explains.

[0257] In the transistor illustrated in FIG. 20, the insulating film 306, the conductive film 310d, and the conductive film 310e are A multilayer film 336 including an oxide semiconductor film is formed on the insulating film 332 .

[0258] The multilayer film 336 includes an oxide semiconductor film 336a and an oxide film 336b. The film 336 has a two-layer structure. A part of the oxide semiconductor film 336a serves as a channel region. In addition, an insulating film 312a is formed so as to contact the multilayer film 336, and the insulating film 312a functions as an insulating film. An oxide film 336b is formed in contact with the oxide semiconductor film 312a. An oxide film 336b is provided between the insulating film 312a and the insulating film 336a.

[0259] The oxide film 336b is composed of one or more elements constituting the oxide semiconductor film 336a. The oxide film 336b is an oxide film containing one of the elements constituting the oxide semiconductor film 336a. Since the oxide semiconductor film 336a and the oxide film 336b are formed as described above, Therefore, the movement of carriers is not hindered at the interface. This increases the field effect mobility of the transistor.

[0260] The oxide film 336b is typically made of In-Ga oxide, In-Zn oxide, In-Mn oxide, or In-Zn-Zn oxide. Zn oxide (M is Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf), In addition, the energy of the bottom of the conduction band is closer to the vacuum level than that of the oxide semiconductor film 336a. The energy of the bottom of the conduction band of the oxide film 336b and the conduction band of the oxide semiconductor film 336a are The difference in energy from the lower end of the band is 0.05 eV or more, 0.07 eV or more, or 0.1 eV or more , or 0.15 eV or more and 2 eV or less, 1 eV or less, 0.5 eV or less, or 0. That is, the electron affinity of the oxide film 336b and the electron affinity of the oxide semiconductor film 336a are The difference from the electron affinity is 0.05 eV or more, 0.07 eV or more, 0.1 eV or more, or 0 .15eV or more and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less It is.

[0261] The oxide film 336b contains In, and thus the carrier mobility (electron mobility) is increased. This is preferable.

[0262] The oxide film 336b is made of Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf. By having a higher atomic ratio of In than In, the following effects may be obtained. (1) Oxide (2) Enlarging the energy gap of the oxide film 336b. (3) To block impurities from the outside. (4) Compared to the oxide semiconductor film 336a (5) Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf is a metal element with strong bonding strength with oxygen, so it is easily mixed with Al, Ti, Ga, Y, Zr, La, By having Ce, Nd or Hf in a higher atomic ratio than In, oxygen vacancies are less likely to occur. do.

[0263] When the oxide film 336b is an In-M-Zn oxide film, the sum of In and M is 100a When expressed as .tomic%, the atomic ratio of In and M is preferably 50 atom %. % or less, M is 50 atomic % or more, and more preferably, In is 25 atomic % or less. c% or less, and M is 75 atomic% or more.

[0264] The oxide semiconductor film 336a and the oxide film 336b are made of In-M-Zn oxide (M is an In-Zn oxide). In the case of Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf, the oxide semiconductor film 3 Compared with 36a, the M (Al, Ti, Ga, Y, Zr, La , Ce, Nd, or Hf) is in a large atomic ratio. At least 1.5 times, preferably at least 2 times, more preferably at least 2 times, more preferably at least 1.5 ...2 times, more preferably at least 2 times, more preferably at least 2 times, more preferably at least 2 times, more preferably This is an atomic ratio that is more than three times higher.

[0265] The oxide semiconductor film 336a and the oxide film 336b are made of In-M-Zn oxide (M is an In-Zn oxide). Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf), oxide film 336b The oxide semiconductor film 336a is In:M If Zn=x2:y2:z2 [atomic ratio], then y1 / x1 is greater than y2 / x2. Preferably, y1 / x1 is 1.5 times or more larger than y2 / x2. More preferably, y1 / x1 is more than twice as large as y2 / x2, and more preferably, y1 / x1 is more than y2 / x In this case, when y1 is equal to or larger than x1 in the oxide semiconductor film, This is preferable because stable electrical characteristics can be imparted to a transistor including the oxide semiconductor film. However, when y1 is three times or more of x1, Therefore, y1 is preferably less than three times x1.

[0266] For example, the oxide semiconductor film 336a may have a composition of In:Ga:Zn=1:1:1 or 3:1: In-Ga-Zn oxide having an atomic ratio of 1:2 can be used. In:Ga:Zn=1:3:n (n is an integer between 2 and 8), 1:6:m (m is 2 or an integer of 1:9:6 or less), or In-Ga-Zn oxide with an atomic ratio of 1:9:6 Note that the atomic ratio of the oxide semiconductor film 336a to the oxide film 336b can be The above atomic ratios are subject to a margin of error of ±20%. In the conductive film 336a, when the ratio of Zn is equal to or higher than Ga, CAAC-OS is easily formed. Very preferable.

[0267] The oxide film 336b is an oxide semiconductor film when the insulating film 312b is formed later. It also functions as a membrane to mitigate damage to 336a.

[0268] The thickness of the oxide film 336b is 3 nm to 100 nm, preferably 3 nm to 50 nm. m or less.

[0269] Similarly to the oxide semiconductor film 336a, the oxide film 336b has a non-single crystal structure, for example. The non-single crystal structure may be, for example, a CAAC-OS (C Axis Aligned Array) structure, which will be described later. ed Crystalline Oxide Semiconductor), polycrystalline structure The structure includes a microcrystalline structure, which will be described later, or an amorphous structure.

[0270] Note that the oxide semiconductor film 336a and the oxide film 336b form an amorphous region and a microcrystalline region. It has two or more types of crystal structure region, polycrystalline structure region, CAAC-OS region, and single crystal structure region. The mixed film may have an amorphous structure region, a microcrystalline structure region, or the like. A region of a polycrystalline structure, a region of a CAAC-OS, or a region of a single crystal structure. It may have a laminated structure of the upper region.

[0271] Here, the oxide film 336b is provided between the oxide semiconductor film 336a and the insulating film 312a. Therefore, impurities and Even if a trap state is formed due to a defect, the trap state and the oxide semiconductor film 336a As a result, electrons flowing through the oxide semiconductor film 336a are transported to the trap state. This makes it possible to increase the on-state current of the transistor and also to reduce the electric field In addition, when an electron is captured in a trap level, the electron This results in a negative fixed charge. As a result, the threshold voltage of the transistor fluctuates. However, because there is a gap between the oxide semiconductor film 336a and the trap states, Therefore, it is possible to reduce the capture of electrons in the trap level, and the fluctuation of the threshold voltage is reduced. can be reduced.

[0272] In addition, the oxide film 336b can block impurities from the outside. In addition, the amount of impurities that moves from the oxide semiconductor film 336a to the oxide semiconductor film 336a can be reduced. For these reasons, the oxide semiconductor film 336a is not easily formed with oxygen vacancies. It is possible to reduce the impurity concentration and the amount of oxygen vacancies in the silicon substrate.

[0273] Note that the oxide semiconductor film 336a and the oxide film 336b are not simply stacked. Continuous junctions (here, specifically, structures in which the energy at the bottom of the conduction band changes continuously between each film) In other words, trap centers and recombination centers are formed at the interfaces of each film. The layer structure is designed so that there are no impurities that would form defect levels like the center. Impurities are present between the stacked oxide semiconductor film 336a and the stacked oxide film 336b. When this happens, the continuity of the energy band is lost, and carriers are trapped or recombined at the interface. They combine and disappear.

[0274] To form continuous junctions, a multi-chamber deposition system equipped with a load lock chamber is required. Each film is laminated in succession using a sputtering device without exposing it to the air. Each chamber in the sputtering apparatus is required for the oxide semiconductor film. In order to remove impurities such as water as much as possible, an adsorption type vacuum pump such as a cryopump is used. High vacuum pump (5×10 -7 Pa~1×10 -4 It is preferable to use a temperature of up to about 10 Pa. Alternatively, a turbo molecular pump and cold trap can be combined to separate the chamber from the exhaust system. It is preferable to prevent the backflow of gases into the bar, especially gases containing carbon or hydrogen. stomach.

[0275] In FIG. 20, the multilayer film 336 is made up of an oxide semiconductor film 336a and an oxide film 336b. However, an oxide film 3 is further provided between the insulating film 306 and the oxide semiconductor film 336a. In this case, the insulating film 306 and the oxide semiconductor film 307 may be provided as a three-layer structure. The thickness of the oxide film provided between the conductive films 336a is preferably smaller than that of the oxide semiconductor film 336a. The thickness of the oxide film is preferably 1 nm or more and 5 nm or less, more preferably 1 nm or more and 3 nm or less. This makes it possible to reduce the amount of variation in the threshold voltage of the transistor.

[0276] <Modification 6: Oxide Semiconductor Film> In the fifth modification, the structure of the multilayer film including the oxide semiconductor film can be modified as appropriate. Here, the transistor 103 is used for description.

[0277] As shown in FIG. 21, the insulating film 306 and the insulating film 312a are provided with an oxide semiconductor film between them. A multi-layer film 336 is formed.

[0278] The multilayer film 336 is formed between the insulating film 306 and the conductive film 310d and the conductive film 310e. The oxide semiconductor film 336a, the conductive film 310d, and the conductive film 31 The oxide semiconductor film 336a is formed on the oxide semiconductor film 336b. The insulating film 312a functions as a channel region. An oxide film 336b is formed so as to contact the insulating film 312a. The oxide film 336b is provided between the oxide semiconductor film 336a and the insulating film 312a. There are.

[0279] In the transistor 103 shown in this modification, the conductive films 310d and 310e are oxide semiconductors. Since the transistor is in contact with the semiconductor film 336a, the oxide semiconductor The contact resistance between the conductive film 336a and the conductive films 310d and 310e is low, and the on-current is improved. It is a transistor.

[0280] In the transistor 103 shown in this modification, the conductive film 310d and the conductive film 310e are oxidized. Since the oxide semiconductor film 336a is in contact with the conductive film 310d, The oxide film 336b can be made thicker without increasing the contact resistance with the conductive film 310e. In this way, plasma damage during the formation of the insulating film 312b or the insulating film The trap levels caused by the inclusion of the constituent elements of the oxide semiconductor 312a and the insulating film 312b are It is possible to suppress the formation of the oxide film 336a and the oxide film 336b in the vicinity of the interface. The transistor shown in the modified example achieves both an improvement in on-current and a reduction in the amount of variation in threshold voltage. It is possible.

[0281] <Modification 7: Transistor structure> In the transistors 102 and 103 described in Embodiment 1, In this embodiment, a plurality of gate electrodes can be provided, which face each other with an oxide semiconductor film interposed therebetween. The transistor 103 will be used for explanation.

[0282] The transistor 103 shown in FIG. 22 includes a conductive film 304c provided over a substrate 302. In addition, the insulating film 305 and the insulating film 306 formed on the substrate 302 and the conductive film 304c are The oxide semiconductor film 3 overlaps with the conductive film 304c with the insulating films 305 and 306 interposed therebetween. 3, a conductive film 310d and a conductive film 310e are in contact with the oxide semiconductor film 308b. In addition, the insulating film 306, the oxide semiconductor film 308b, the conductive film 310d, and the conductive film 310 On the insulating film 312, an insulating film 312a and an insulating film 312b are laminated. The oxide semiconductor film 30 is formed with the insulating film 312 and the insulating film 314 interposed therebetween. A light-transmitting conductive film 316c overlaps with 8b.

[0283] The conductive film 304c and the light-transmitting conductive film 316c are formed through the oxide semiconductor film 308b. Note that the conductive film 304c and the light-transmitting conductive film 316c face each other. The light-transmitting conductive film 316c functions as a light-transmitting conductive film 316b. This is preferable because it makes it possible to reduce the number of steps.

[0284] The transistor 103 in this modification has a conductive layer facing the oxide semiconductor layer 308b therebetween. The conductive film 304c and the light-transmitting conductive film 316c are By applying different potentials to the conductive film 316c, the threshold voltage of the transistor 103 is Can be controlled.

[0285] In addition, the configuration and method described in this embodiment may be applied to configurations and methods described in other embodiments and examples. and the like.

[0286] (Embodiment 3) In this embodiment, a transistor included in the semiconductor device described in the above embodiment is In the above, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 3 An embodiment applicable to the multilayer film 336 will be described. Although the description will be given using a semiconductor film as an example, the oxide film included in the multilayer film may have a similar structure. This can be done.

[0287] The structure of the oxide semiconductor film will be described below.

[0288] Oxide semiconductor films are roughly classified into single-crystal oxide semiconductor films and non-single-crystal oxide semiconductor films. The non-single-crystal oxide semiconductor film includes an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, a polycrystalline oxide semiconductor film, and a polycrystalline oxide semiconductor film. These films include compound semiconductor films and CAAC-OS films.

[0289] The amorphous oxide semiconductor film has irregular atomic arrangement and does not contain crystalline components. The oxide semiconductor film does not have any crystal parts even in a microscopic region, and the entire film has a completely amorphous structure. A typical example is an oxide semiconductor film.

[0290] The microcrystalline oxide semiconductor film is, for example, a microcrystal (nanocrystal) having a size of 1 nm or more and less than 10 nm. Therefore, the microcrystalline oxide semiconductor film has a higher crystallinity than the amorphous oxide semiconductor film. The atomic arrangement is highly regular. Therefore, the microcrystalline oxide semiconductor film has a higher atomic order than the amorphous oxide semiconductor film. It has the advantage of having a lower density of defect states than silicon.

[0291] The CAAC-OS film is one of the oxide semiconductor films that has multiple crystal parts. The crystal part is small enough to fit inside a cube with one side less than 100 nm. The crystal parts contained in the OS film are cubes with one side less than 10 nm, 5 nm, or 3 nm. The CAAC-OS film has a smaller size than the microcrystalline oxide semiconductor film. The defect density is low. The CAAC-OS film is described in detail below. cormorant.

[0292] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed using a quartz crystal microscope, clear boundaries between the crystals were observed. It is not possible to confirm the grain boundary. It can be said that the AAC-OS film is less susceptible to the decrease in electron mobility caused by grain boundaries.

[0293] The CAAC-OS film was observed by TEM from a direction roughly parallel to the sample surface (cross-sectional TEM observation). When the metal atoms are observed, it can be confirmed that they are arranged in layers in the crystal part. Each layer of the CAAC-OS film is formed on a surface on which the film is to be formed (also called a surface on which the film is to be formed) or on a concave surface on the upper surface. The shape reflects a convexity, and is aligned parallel to the surface on which the CAAC-OS film is formed or the upper surface.

[0294] On the other hand, the CAAC-OS film was observed by TEM from a direction roughly perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystals. However, no regularity was observed in the arrangement of metal atoms between different crystal regions. do not have.

[0295] Cross-sectional and planar TEM observations revealed that the crystals in the CAAC-OS film had an orientation. It can be seen that...

[0296] X-ray diffraction (XRD) of CAAC-OS film When the structure was analyzed using the device, for example, CAAC-OS with InGaZnO4 crystals was In the out-of-plane analysis of the film, the diffraction angle (2θ) peaked at around 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis faces the surface on which the film is formed or the upper surface. It can be seen that it is oriented in a roughly vertical direction.

[0297] On the other hand, in-p X-rays are incident on the CAAC-OS film from a direction approximately perpendicular to the c-axis. In the lane method, a peak may appear at 2θ around 56°. is attributed to the (110) plane of the InGaZnO4 crystal. In the case of a nitride semiconductor film, 2θ is fixed at around 56°, and the normal vector of the sample surface is the axis (φ axis). When the sample is rotated and analyzed (φ scan), a crystal plane equivalent to the (110) plane is detected. In contrast, in the case of the CAAC-OS film, six peaks are observed, which are assigned to Even when φ is fixed at around 56° and scanned, no clear peak appears.

[0298] From the above, it is considered that the orientation of the a-axis and b-axis is uniform between different crystal regions in the CAAC-OS film. Although it is irregular, it has a c-axis orientation, and the c-axis is parallel to the normal vector of the surface on which it is formed or the upper surface. Therefore, the layered structure confirmed by the cross-sectional TEM observation mentioned above is consistent with the Each layer of arranged metal atoms is in a plane parallel to the ab plane of the crystal.

[0299] The crystalline part is formed when the CAAC-OS film is formed or after a crystallization process such as a heat treatment. As described above, the c-axis of the crystal is aligned to the surface on which the CAAC-OS film is to be formed. For example, in the CAAC-OS film, When the shape is changed by etching, the c-axis of the crystal is aligned with the CAAC-OS film. It may not be parallel to the face or top surface normal vector.

[0300] In addition, the crystallinity in the CAAC-OS film does not have to be uniform. When the crystalline part of the film is formed by crystal growth from the vicinity of the top surface of the CAAC-OS film, The area near the surface may have a higher crystallinity than the area near the surface on which it is formed. When impurities are added to the AC-OS film, the crystallinity of the region to which the impurities are added changes, resulting in a partial In some cases, regions of differing crystallinity may be formed.

[0301] In addition, the out-of-plane crystal structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ of around 36° may be due to the c-axis orientation in some parts of the CAAC-OS film. The CAAC-OS film contains crystals that do not have the 2θ value of about 31°. It is preferable that the spectrum shows a peak at 2θ of about 36° and does not show a peak at 2θ of about 36°.

[0302] The electrical characteristics of transistors using CAAC-OS films change when irradiated with visible or ultraviolet light. Therefore, the transistor has high reliability.

[0303] In addition, in the case of CAAC-OS films, spots (bright spots) are observed in the electron diffraction pattern. In particular, electron beams with a beam diameter of 10 nm or less, or 5 nm or less, are used. The obtained electron beam diffraction pattern is called a microelectron beam diffraction pattern.

[0304] FIG. 23(A) is an example of a nanoelectron diffraction pattern of a sample having a CAAC-OS film. . Here, the sample is cut in a direction perpendicular to the film formation surface of the CAAC-OS film and thinned to a thickness of about 40 n m. Also, here, an electron beam with a beam diameter of 1 nmφ is incident from a direction perpendicular to the cut surface of the sample . From FIG. 23(A), it can be seen that spots are observed in the nanoelectron diffraction pattern of the CAAC-OS film.

[0305] Note that the oxide semiconductor film may be, for example, a laminated film having two or more of an amorphous oxide semiconductor film, a microcrystalline oxide semiconductor film, and a C AAC-OS film.

[0306] <Method for Producing CAAC-OS> The c-axis of the crystal part included in CAAC-OS aligns in a direction parallel to the normal vector of the film formation surface of CAAC-OS or the normal vector of the surface. Therefore, depending on the shape of CAAC-OS (the cross-sectional shape of the film formation surface or the cross-sectional shape of the surface), they may face different directions. Note that the direction of the c-axis of the crystal part is parallel to the normal vector of the film formation surface or the surface when CAAC-OS is formed. The crystal part is formed by film formation or by performing a crystallization treatment such as heat treatment after film formation.

[0307] Three methods can be cited as the method for forming CAAC-OS.

[0308] The first method is a method of forming a crystal part in which the c-axis of the crystal part included in the oxide semiconductor film aligns in a direction parallel to the normal vector of the film formation surface or the surface by forming an oxide semiconductor film with a film formation temperature of 100°C or higher and 450°C or lower. of the normal vector.

[0309] The second method is to form an oxide semiconductor film to a small thickness, and then heat the film at a temperature of 200° C. to 700° C. By performing heat treatment, the c-axis of a crystal part included in the oxide semiconductor film is aligned along the normal vector of the formation surface. This is a method for forming crystals that are aligned in a direction parallel to the normal vector of the crystal or surface.

[0310] The third method is to form a thin oxide semiconductor film as a first layer, and then heat the film at 200° C. or higher for 700 Heat treatment at 0.4 °C or less is performed, and then a second oxide semiconductor film is formed. The c-axis of the crystal part contained in the conductive film is aligned with the normal vector of the surface on which it is formed or the normal vector of the surface. This is a method for forming crystal parts that are aligned in parallel directions.

[0311] Here, a method for forming a CAAC-OS using the first method will be described.

[0312] <Target and target preparation method> In addition, the CAAC-OS can be used as a sputtering target for a polycrystalline oxide semiconductor. The sputtering target is used to deposit a thin film. When the ions collide, the crystalline regions in the sputtering target cleave from the ab plane. The sputtered particles are either flat or pellet-shaped with a surface parallel to the ab plane. In this case, the plate-like or pellet-like sputtered particles may become crystalline. By reaching the deposition surface while maintaining this state, a CAAC-OS film can be deposited. .

[0313] In addition, in order to form a CAAC-OS film, the following conditions are preferably applied.

[0314] By reducing the amount of impurities mixed in during film formation, it is possible to prevent the crystal state from being destroyed by impurities. For example, the concentration of impurities (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be In addition, the impurity concentration in the deposition gas may be reduced. Film formation at -80°C or lower, preferably -100°C or lower, more preferably -120°C or lower Gas is used.

[0315] In addition, by increasing the heating temperature (for example, the substrate heating temperature) of the surface to be film-formed during film formation, Specifically, the temperature of the surface on which the film is to be formed increases, and then the sputtered particles begin to migrate. The temperature is set to 100° C. or higher and 740° C. or lower, preferably 200° C. or higher and 500° C. or lower. By increasing the temperature of the surface during deposition, the plate-shaped sputtering particles reach the surface. When the sputtering particles are mixed with the surface, migration occurs on the surface to be coated, and the flat surface of the sputtering particles The sputtering particles adhere to the surface on which the film is to be formed, although this varies depending on the type of oxide. , the diameter (equivalent circle diameter) of the plane parallel to the ab plane is 1 nm or more and 30 nm or less, or 1 nm or more The diameter of the plate-shaped sputtered particles is about 10 nm or less. The hexagonal faces of the plate-shaped sputtered particles are in the ab plane. In this case, the direction perpendicular to the hexagonal surface is the c-axis direction. It is in the direction.

[0316] In addition, the sputtering target is sputtered using oxygen cations. Therefore, the plasma damage during film formation can be reduced. When it hits the surface of the ring target, the crystallinity of the sputtering target decreases. It is possible to suppress the crystallization or amorphization.

[0317] In addition, the sputtering target is sputtered using oxygen or argon cations. By ringing, when a flat sputtering particle has a hexagonal column shape, the hexagonal surface is The corners of the hexagonal faces can be positively charged. As a result, the positive charges in each sputtering particle repel each other, maintaining the flat shape. It can be held.

[0318] In order for the corners of the surface of a flat sputtered particle to have a positive charge, a direct current ( It is preferable to use a DC power supply. Note that a radio frequency (RF) power supply or an alternating current (AC) power supply may also be used. However, the RF power source is a sputtering device capable of depositing a film on a large-area substrate. In addition, DC power is preferable to AC power for the following reasons: It is possible.

[0319] When an AC power source is used, adjacent targets alternate between cathode and anode potentials. When flat sputtering particles are positively charged, they repel each other. However, when using an AC power source, the plate shape can be maintained. Since there is a period of time when no electric field is applied to the plate-shaped sputtering particle, the charge on the plate-shaped sputtering particle The structure of the sputtered particles may be destroyed due to the loss of the AC current. It has been found that using a DC power supply is preferable to using a DC power supply.

[0320] In addition, by increasing the oxygen ratio in the deposition gas and optimizing the power, plasma damage during deposition is reduced. The oxygen ratio in the deposition gas is preferably 30% by volume or more, and more preferably 100% by volume or more. Expressed as volume percent.

[0321] As an example of a sputtering target, an In-Ga-Zn-O compound target is used. The details are shown below.

[0322] InO X powder, GaO Y Powder, and ZnO Z The powders are mixed in a specified number of moles and pressurized. Then, it is heated at a temperature between 1000℃ and 1500℃ to produce polycrystalline In-G The target is a Zn-based compound. The pressure treatment is performed while cooling (or cooling naturally). The reaction may be performed while heating or while heating. In addition, X, Y and Z are any positive numbers. Here, the predetermined molar ratio is, for example, InO X powder, GaO Y Powder and ZnO Z powder However, 2:2:1, 8:4:3, 3:1:1, 1:1:1, 4:2:3, 3:1:2, 1: The ratio is 3:2, 1:6:4, or 1:9:6. The powder type and the mixture ratio are The ol ratio may be appropriately changed depending on the sputtering target to be produced.

[0323] By using a sputtering target in the above manner, the thickness is uniform and In this way, an oxide semiconductor film with uniform crystal orientation can be formed.

[0324] <Polycrystalline oxide semiconductor> The polycrystalline oxide semiconductor includes a plurality of crystal grains. The following may be present:

[0325] In the case of polycrystalline oxide semiconductors, for example, crystal grains can be confirmed in TEM images. Crystal grains contained in a polycrystalline oxide semiconductor may be, for example, , 2nm to 300nm, 3nm to 100nm, or 5nm to 50nm In addition, polycrystalline oxide semiconductors are often observed with a grain size of 100 nm or less in a TEM image. In some cases, the boundaries between the amorphous parts and the crystal grains, and the boundaries between the crystal grains, can be confirmed. In the case of a polycrystalline oxide semiconductor, for example, grain boundaries may be observed in a TEM image.

[0326] The polycrystalline oxide semiconductor has, for example, a plurality of crystal grains, and the crystal grains have different orientations. In addition, the polycrystalline oxide semiconductor may be analyzed by, for example, an XRD apparatus. When performing out-of-plane analysis, single or multiple peaks may appear. For example, in the case of a polycrystalline IGZO film, the 2θ value, which indicates the orientation, peaks at around 31°, or In some cases, multiple peaks indicating several different orientations appear. For example, spots may be observed in the electron diffraction pattern.

[0327] A polycrystalline oxide semiconductor has high crystallinity and therefore high electron mobility. Therefore, a transistor using a polycrystalline oxide semiconductor for a channel region has a high current. However, in polycrystalline oxide semiconductors, impurities may segregate at grain boundaries. In addition, the grain boundaries of a polycrystalline oxide semiconductor become defect states. Since the channel region of a polycrystalline oxide semiconductor may be a carrier generation source or a trap state, The transistor using CAAC-OS for the channel region is In all cases, the electrical characteristics may vary significantly, resulting in a transistor with low reliability.

[0328] The polycrystalline oxide semiconductor is formed by a heat treatment at a high temperature or a laser light treatment. can be done.

[0329] <Microcrystalline oxide semiconductor> In the microcrystalline oxide semiconductor, for example, crystals can be clearly seen in the TEM observation image. The crystal parts contained in the microcrystalline oxide semiconductor may have a size of, for example, 1 nm or more. The size is often less than 100 nm, or between 1 nm and 10 nm. For example, microcrystals with a size of 1 nm or more and 10 nm or less are called nanocrystals (nc). The oxide semiconductor with nanocrystals is called nc-OS (nanocrystalline In addition, nc-OS is called TE In the observation image by M, the boundary between the crystal parts may not be clearly visible. For example, nc-OS does not have clear grain boundaries in TEM images, so impurities are In addition, since nc-OS does not have clear grain boundaries, for example, defects are unlikely to occur. The level density is unlikely to be high. In addition, the nc-OS does not have clear grain boundaries, for example. Therefore, the decrease in electron mobility is small.

[0330] For example, the nc-OS can be used in a microscopic area (e.g., an area of ​​1 nm to 10 nm). In some cases, the atomic arrangement has periodicity. For example, nc-OS has a crystalline part and a crystalline part. Since there is no regularity between the atoms, the atomic arrangement does not show periodicity macroscopically, or the long-range Therefore, depending on the analytical method, for example, In some cases, it may be difficult to distinguish nc-OS from amorphous oxide semiconductors. The analysis was performed by the out-of-plane method using X-rays with a beam diameter larger than the crystal part. In some cases, the peak indicating the orientation may not be detected. The electron beam has a beam diameter larger than the target (for example, 20 nmφ or more, or 50 nmφ or more). In the electron diffraction pattern used, a halo pattern may be observed. For example, the OS has a beam diameter that is the same as or smaller than the crystal part (for example, 10 nmφ or less, In the ultrafine electron diffraction pattern using an electron beam of 5 nm or less, spots were observed. In addition, the electron micro diffraction pattern of nc-OS may show a circular pattern. In addition, the electron diffraction pattern of nc-OS shows bright areas. For example, multiple spots may be observed within the region.

[0331] FIG. 23(B) shows an example of an electron microbeam diffraction pattern of a sample having an nc-OS. In this example, the sample was cut in a direction perpendicular to the surface on which the nc-OS was formed, and the thickness was about 40 nm. In this experiment, an electron beam with a beam diameter of 1 nm was applied to the cut surface of the sample. The electron diffraction pattern of nc-OS is shown in Fig. 23(B). A circular area of ​​high brightness is observed, and multiple spots are observed within the area. It can be seen that this is possible.

[0332] nc-OS has periodic atomic arrangement in small regions, so it is amorphous. The defect density is lower than that of oxide semiconductors. However, the nc-OS has a crystalline structure. Since there is no regularity between the nuclei, the density of defect states is higher than that of CAAC-OS. The absorption coefficient, as determined by the constant photocurrent measurement method (CPM), is preferably less than 1 / cm. 5×10 -1 / cm, more preferably less than 5×10 -2 / cm or less.

[0333] Therefore, the carrier density of the nc-OS may be higher than that of the CAAC-OS. Oxide semiconductors with high carrier density can have high electron mobility. A transistor using an -OS for a channel region can have high field-effect mobility. In addition, the nc-OS has a higher defect density than the CAAC-OS, which leads to the trap state. Therefore, the potential density of the transistor using nc-OS for the channel region can be increased. The electrical characteristics of the transistors using CAAC-OS in the channel region are significantly different from those of the transistors using CAAC-OS in the channel region. This can result in a transistor that is too slow and unreliable.

[0334] <Method for manufacturing microcrystalline oxide semiconductor film> Next, a method for forming a microcrystalline oxide semiconductor film will be described below. The film is heated to a temperature of from room temperature to 75° C., preferably from room temperature to 50° C., in an atmosphere containing oxygen. The film is formed by sputtering under an oxygen-containing atmosphere. As a result, oxygen vacancies in the microcrystalline oxide semiconductor film are reduced, and the film includes a microcrystalline region. This can be done.

[0335] By reducing oxygen vacancies in a microcrystalline oxide semiconductor film, the film has stable physical properties. In particular, when a semiconductor device is manufactured by using a microcrystalline oxide semiconductor film, The oxygen vacancies in the microcrystalline oxide semiconductor film act as donors, and carriers are introduced into the microcrystalline oxide semiconductor film. This generates electrons that are the cause of fluctuations in the electrical characteristics of the semiconductor device. By manufacturing a semiconductor device using a microcrystalline oxide semiconductor film in which defects are reduced, Therefore, a high-performance semiconductor device can be obtained.

[0336] In the microcrystalline oxide semiconductor film, oxygen vacancies occur when the oxygen partial pressure in the film formation atmosphere is increased. More specifically, the oxygen partial pressure in the film formation atmosphere is preferably reduced to 33%. It is preferable that the amount is equal to or more than that.

[0337] Note that a target used in forming the microcrystalline oxide semiconductor film by a sputtering method is The CAAC-OS can use the same target and its preparation method as those of the CAAC-OS.

[0338] In addition, nc-OS can be formed even if it contains a relatively large amount of impurities. It is easier to form than CAAC-OS and can be used preferably for some applications. For example, nc-OS can be formed by a deposition method such as sputtering using an AC power source. The sputtering method using an AC power source is capable of depositing a film on a large substrate with high uniformity. Therefore, it is possible to develop a semiconductor device having a transistor with nc-OS in the channel region. The device can be produced productively.

[0339] <Amorphous oxide semiconductor> For example, an amorphous oxide semiconductor has a disordered atomic arrangement and does not have a crystal part. An amorphous oxide semiconductor has an amorphous state like quartz, for example, and has regular atomic arrangement. Not seen.

[0340] In the amorphous oxide semiconductor, for example, crystal parts can be confirmed in the observation image by TEM. There may not be.

[0341] Amorphous oxide semiconductors are analyzed by the out-of-plane method using an XRD device. In addition, when the amorphous oxide semiconductor is used, the peak indicating the orientation may not be detected. For example, a halo pattern may be observed in the electron diffraction pattern. For example, no spots can be observed in the ultrafine electron diffraction pattern of a halo semiconductor. -patterns may be observed.

[0342] Amorphous oxide semiconductors are formed by, for example, containing a high concentration of impurities such as hydrogen. Therefore, the amorphous oxide semiconductor may be formed by, for example, It is an oxide semiconductor containing

[0343] When an oxide semiconductor contains a high concentration of impurities, defects such as oxygen vacancies occur in the oxide semiconductor. Therefore, an amorphous oxide semiconductor with a high impurity concentration has a high density of defect states. In addition, amorphous oxide semiconductors have low crystallinity, so The defect level density is higher than that of

[0344] Therefore, the amorphous oxide semiconductor has a higher carrier density than the nc-OS. Therefore, a transistor using an amorphous oxide semiconductor for a channel region has a Therefore, normally-on electrical characteristics are required. In some cases, an amorphous oxide semiconductor can be suitably used for a transistor in which defects are formed. Since the density of states is high, the density of trap states may also be high. Transistors using conductors for the channel region use CAAC-OS or nc-OS for the channel region. Compared to transistors used in the field, these transistors have large fluctuations in electrical characteristics and are less reliable. However, amorphous oxide semiconductors contain a relatively large amount of impurities due to the deposition method. Since the film can be formed by the above method, the film can be easily formed and is preferably used depending on the application. For example, spin coating, sol-gel, dipping, spraying, etc. method, screen printing method, contact printing method, inkjet printing method, roll coating method Alternatively, the amorphous oxide semiconductor may be formed by a film forming method such as a mist CVD method. A semiconductor device having a transistor in which an amorphous oxide semiconductor is used for a channel region has a high productivity. It can be made taller.

[0345] In addition, for example, the density of an oxide semiconductor is high when the number of defects is small. For example, when the crystallinity is high, the density is high. For example, the density of single-crystal oxide semiconductors is high when the impurity concentration is low. In addition, the CAAC-OS has a higher density than a microcrystalline oxide semiconductor. In addition, for example, a polycrystalline oxide semiconductor may have a higher density than a microcrystalline oxide semiconductor. In addition, for example, a microcrystalline oxide semiconductor may have a higher density than an amorphous oxide semiconductor. It may be denser than the body.

[0346] (Embodiment 4) In this embodiment mode, a driver circuit portion of the display device shown in the above embodiment mode will be described.

[0347] One aspect of the present embodiment is a shift register unit and an electric The present invention has a demultiplexer circuit for connecting multiple signals to each other, and n signal lines (n is a natural number of 4 or more). The shift register unit is electrically connected to one or more of the n signal lines, and is demultiplexed. The plexer circuit is electrically connected to at least one (n-3) of the n signal lines. The driving circuit is characterized by the above.

[0348] In another aspect of this embodiment, a shift register having m shift registers (m is a natural number equal to or greater than 3) is provided. a unit, and m demultiplexers electrically connected to each of the m shift register units; A multiplexer circuit and n signal lines (n is a natural number of 4 or more), and m shift registers are arranged in the same order. Each of the star units is electrically connected to one or more of the n signal lines and has m dema Each multiplexer circuit is electrically connected to one or more (n-3) or less of the n signal lines. , and one of the m shift register units is connected to one of the m shift register units. One of the outputs of the demultiplexer circuit electrically connected to the previous-stage shift register unit is input, and one of the m shift register units is The output of the demultiplexer circuit is electrically connected to the shift register unit at the rear stage. The driving circuit is characterized in that one

[0349] In addition, another aspect of this embodiment is a shift register unit and a demultiplexer circuit. The shift register unit has a signal line and n signal lines (n is a natural number of 4 or more). a first transistor to a sixth transistor; and a second transistor. The transistor has a source and a drain, one of which is electrically connected to a high power supply potential line, and The other input is connected to one of the source and drain of the second transistor and the demultiplexer circuit. a gate electrically connected to the set signal line; and a second transistor The other of the source and drain is electrically connected to a low power supply potential line, and the gate is The lexer circuit, one of the source and drain of the fourth transistor, the source of the fifth transistor and one of the source and drain of the sixth transistor. The third transistor has one of a source and a drain electrically connected to the high power supply line. the other of the source and drain of the fourth transistor is connected to the other of the source and drain of the fourth transistor a gate electrically connected to one of the n signal lines; and a fourth transistor The gate of the fifth transistor is electrically connected to another one of the n signal lines. The other of the source and drain is electrically connected to a low power supply potential line, and the gate is electrically connected to a set signal line. The sixth transistor has the other of the source and the drain electrically connected to the high power supply potential line. the gate is electrically connected to a reset signal line, and the demultiplexer circuit is There are a number of buffers (a is a natural number between 1 and (n-3) inclusive), and each of the a buffers This is the other of the source and drain of the first transistor and the gate of the second transistor. Each of the a buffers is electrically connected to one of the n signal lines. a driving circuit electrically connected to the first buffer, each of the first buffer having an output terminal; It is a circuit.

[0350] A specific configuration will be described with reference to the drawings. FIG. 29 shows an example of a drive circuit for a display device. The gate driver circuit 600 includes a plurality of shift registers. A shift register unit (SR) 601, a dummy stage shift register unit (SR_D) 6 02, a demultiplexer circuit (DM P (also called DEMUX) 603, which is electrically connected to the shift register unit 602 A demultiplexer circuit (DMP (also called DEMUX)) 604, a start pulse SP, It has signal lines that transmit clock signals (CLK1 to CLK8).

[0351] Shift register unit 601 (here, the first stage shift register unit is used) The set signal LIN (here, the start pulse) is The inputs are the signal SP, the reset signal RIN, and the clock signals (CLK6 and CLK7 in this example). An example of a specific circuit configuration is shown in FIG. The set 601 includes a first transistor 611 to a sixth transistor 616 .

[0352] One of the source and drain of the first transistor 611 is connected to the high power supply potential line VDD. The other of the source and drain of the first transistor 611 is connected to the second transistor 6 12 and the input terminal FN1 of the demultiplexer circuit 603. The gate of the first transistor 611 is connected to a set signal LIN. The other of the source and drain of the transistor 612 is connected to the low power supply potential line VSS. The gate of the second transistor 612 is connected to the input terminal FN2 of the demultiplexer circuit 603, One of the source and drain of the fourth transistor 614 and the source of the fifth transistor 615 and one of the source and drain of the sixth transistor 616. One of the source and drain of the third transistor 613 is connected to the high power supply line VDD The other of the source and drain of the third transistor 613 is connected to the fourth transistor the other of the source and drain of the third transistor 614, The gate of the fourth transistor 614 is connected to the clock signal CLK7. The other of the source and drain of the fifth transistor 615 is , the gate of the fifth transistor 615 is connected to the low power supply line VSS, and the gate of the fifth transistor 616 is connected to the set signal L The other of the source and drain of the sixth transistor 616 is connected to a high power supply voltage The gate of the sixth transistor 616 is connected to the potential line VDD. The gate of the sixth transistor 616 is connected to the reset signal RIN. The other of the source and drain of the first transistor 611 and the second transistor The part where one of the source and drain of the transistor 612 is electrically connected is designated as a node FN1. Also, the gate of the second transistor 612, the source of the fourth transistor 614 and one of the source and drain of the fifth transistor 615 and one of the source and drain of the sixth transistor The part where one of the source and drain of the transistor 616 is electrically connected is called a node FN2. It is called.

[0353] In addition, the shift register unit 601 in the 8a+1th stage (where a is 0 or a natural number) has a clock. The clock signals CLK6 and CLK7 are input, and the clock signal CLK6 is generated in the 8a+2nd stage (where a is 0 or a natural number). The clock signals CLK3 and CLK4 are input to the soft register unit 601. The shift register unit 601 in the +3rd stage (where a is 0 or a natural number) receives a clock signal C LK1 and CLK8 are input, and the 8a+4th stage (a is 0 or a natural number) shift register The unit 601 receives the clock signals CLK5 and CLK6, and the 8a+5th stage (a The shift register unit 601 (where CLK2 is 0 or a natural number) receives clock signals CLK2 and C LK3 is input, and the 8a+6th stage (a is 0 or a natural number) shift register unit 60 Clock signals CLK7 and CLK8 are input to 1, and 8a+7th stage (a is 0 or The shift register units 601 (each of which is a natural number) are input with clock signals CLK4 and CLK5. In the 8(a+1)th stage (where a is 0 or a natural number) shift register unit 601, Clock signals CLK1 and CLK2 are input.

[0354] The shift register unit 602, which is a dummy stage, receives a set signal as shown in FIG. The LIN signal and clock signals (here, CLK3 and CLK4) are input. An example of the circuit configuration is shown in FIG. The circuit includes a transistor 611 to a fifth transistor 615 .

[0355] One of the source and drain of the first transistor 611 is connected to the high power supply potential line VDD. The other of the source and drain of the first transistor 611 is connected to the second transistor 6 12 and the input terminal FN1 of the demultiplexer circuit 604. The gate of the first transistor 611 is connected to a set signal LIN. The other of the source and drain of the transistor 612 is connected to the low power supply potential line VSS. The gate of the second transistor 612 is connected to the input terminal FN2 of the demultiplexer circuit 604, One of the source and drain of the fourth transistor 614 and the fifth transistor 615 The source and drain of the third transistor 613 are connected to one of the source and drain. One of the terminals is connected to a high power supply line VDD, and the other terminal is connected to the source and drain of the third transistor 613. The other of the drains is connected to the other of the source and drain of the fourth transistor 614. The gate of the third transistor 613 receives the clock signal CLK4. The clock signal CLK3 is input to the gate of the fifth transistor 614. The other of the source and drain of the fifth transistor is connected to the low power supply potential line VSS. The gate of the first transistor 611 receives a set signal LIN. The other of the source and drain and one of the source and drain of the second transistor 612 The electrically connected portion is called a node FN1. one of the source and drain of the fourth transistor 614 and the fifth transistor 6 The portion where one of the source and drain of 15 is electrically connected is called a node FN2.

[0356] The demultiplexer circuit 603 and the demultiplexer circuit 604 are shown in FIG. As shown in FIG. 33(A), a clock signal, a shift register unit 601 and a shift register The output signal from the input unit 602 (the signal input to the input terminal FN1 and the input terminal FN2) A specific example of the circuit configuration is shown in FIG. 33B. Demultiplexer circuit 603 and demultiplexer circuit 604 has a buffer (BUF) 605.

[0357] An example of a specific circuit configuration of the buffer 605 is shown in FIG. One of the source and drain of the clock signal CLK (clock signal CLK1 to CLK 8) is input, and the other of the source and drain of the seventh transistor 617 is connected to one of the source and drain of the eighth transistor 618 and the output terminal, The gate of the seventh transistor 617 is connected to the node FN1. The other of the source and drain of the eighth transistor is connected to the low power supply potential line VSS. The gate of the transistor 618 is connected to a node FN2.

[0358] In addition, the shift register unit is shifted as shown in FIG. 35(A) and FIG. 35(B). In addition to the resistor unit 601, a transistor 621, a transistor 622, a transistor Alternatively, the shift register unit 601a may include a capacitor 623 and a capacitor 624. The gate of the transistor 623 receives a reset signal RES.

[0359] Similarly, the shift register unit, which is a dummy stage, is shown in FIG. 36(A) and FIG. 36(B). As shown, in addition to the shift register unit 602, transistors 621 and 6 22. A shift register unit 602a having a transistor 623 and a capacitor 624 The gate of the transistor 623 may receive a reset signal RES. do.

[0360] To initialize the shift register unit, input the reset signal RES pulse. The transistor 623 is turned on, and the potential of the node FN2 is set to the potential of the high potential power supply line VDD. In addition, the second transistor 612 and the transistor 6 By turning on 21, the potential of the node FN1 becomes the potential of the low-potential power line VSS, The shift register unit can be initialized. The reset signal RES initializes all shift registers. The signal is input to the soft register unit via a common signal line.

[0361] In addition, the buffer 605 may be further connected to a transistor as shown in FIG. 37(A) and FIG. 37(B). 625 and a buffer 605a including a capacitor 619 may be substituted.

[0362] The capacitive element functions as a storage capacitor that stores electric charges.

[0363] Note that each transistor in this embodiment is formed using the oxide semiconductor In particular, the gate of a transistor and the The above embodiment is to be taken into consideration when one of the source and drain is electrically connected. This makes it possible to further reduce the frame area of ​​the display device.

[0364] In the first stage shift register unit 601, clock signals CLK1 to CLK5 are The demultiplexer circuit 603 outputs the output signal OUT Outputs OUT1 to OUT5.

[0365] In addition, by fixing node FN2 at a high potential during the period when the gate selection output is not being output, The second transistor 612 and the eighth transistor 618 are always on to keep the output at a low voltage. However, the cutoff current (gate voltage When the drain current (which flows when the input voltage is 0 V) ​​is large, the charge on node FN2 is Since the charge leaks through the resistor 615, it is necessary to periodically replenish the charge. The third transistor 613 and the fourth transistor 614 are driven by clock signals CLK6 and CLK7. The transistor 614 is made conductive, and the charge of the node FN2 is supplied from the high power supply potential line VDD. In addition, during the gate selection output period of the first-stage shift register unit 601 (when the node FN1 The period during which the potential is high starts from the rising edge (set) of the start pulse SP, which will be explained later. The clock signal CLK7 is reset (rising) and two clock signals are used. Therefore, the timing of the gate selection output period and the periodic charge compensation are not overlapped. do.

[0366] In addition, in the first stage shift register unit 601, where is the clock signal CLK8? The timing of this clock signal is also important, as it is necessary to periodically replenish the charge. This is designed to prevent this from happening.

[0367] Similarly, in the second stage shift register unit 601, clock signals CLK1 and CL K2, CLK6 to CLK8 are input to a demultiplexer circuit 603, and demultiplexed. The output circuit 603 outputs the output signals OUT1 to OUT5. LK4 has the function of periodically replenishing the charge. In the data unit 601, the clock signal CLK5 is not input anywhere.

[0368] The same applies to the third and subsequent shift register units 601. In one unit, five clock signals are input to a demultiplexer circuit 603, which demultiplexes the The multiplexer circuit 603 outputs five output signals. The other two clock signals are: It functions to periodically replenish the charge and is input to the shift register unit 601. Additionally, the other clock signal is not input anywhere.

[0369] The same is true for the shift register unit 602, which is a dummy stage, and the clock signal CL K1 and CLK2 are input to a demultiplexer circuit 604, and 4 outputs output signals DUMOUT1 and DUMOUT2. Clock signals CLK3 and CLK4 has a function of periodically replenishing the charge.

[0370] In addition, in the present embodiment, the number of clock signals is eight, but this is not limited to eight. The number of signals must be at least four. For example, if the number of clock signals is n, then Since there are three clock signals that do not contribute to the output signal, the number of output signals is n-3.

[0371] In other words, for each stage of the shift register unit, n signal lines are required to transmit the clock signal. By connecting them, n-3 output signals can be output. The larger n is, the more the output The ratio of signal lines that transmit clock signals that are not supplied to the shift register unit is reduced. Compared to the conventional configuration where one output signal is output per stage, This reduces the area occupied by the gate driver circuit 600, making it possible to reduce the width of the gate driver circuit 600. .

[0372] Here, the narrowing of the frame of the gate driver circuit 600 will be briefly described. FIG. 38(B) is a block diagram of a conventional gate driver circuit, and FIG. 38(C) is a block diagram of the gate driver circuit of the present embodiment. FIG. 2 is a block diagram of a driver circuit.

[0373] The conventional gate driver circuit shown in FIG. 38(A) has a shift register unit SR1 stage. A signal line CLK_LINE that transmits four clock signals is connected to one buffer B. One signal is output by the UF. On the other hand, the gate driver of this embodiment shown in FIG. The driver circuit is a signal driver that transmits eight clock signals per stage of the shift register unit SR. The signal line CLK_LINE is connected to five buffers BUF, which output five signals.

[0374] The gate driver circuit of the present embodiment has a shift register, which is different from the conventional gate driver circuit. The horizontal layout width can be reduced by one row of star units. The vertical layout width is The gate driver circuit cost increases by the amount of the buffer BUF (here, 5 times the conventional amount). Therefore, the horizontal layout width per stage of the shift register unit is reduced. This makes it possible to achieve a narrower frame. The number of signal lines CLK_LINE will increase compared to the conventional method. The load capacitance of each INE line is reduced. Therefore, the signal line CLK_LINE is made thinner. Therefore, even if the load resistance is increased (because the time constant = load capacitance x load resistance), the delay time does not change. Therefore, to keep the time constant the same, the layout width is reduced by narrowing the signal line width. Therefore, even if the signal line CLK_LINE increases, the gate driver The width of the driver circuit can be narrowed.

[0375] Next, the operation of the gate driver circuit 600 will be described with reference to the timing chart shown in FIG. Here, a set signal LIN, a reset signal RIN, and a clock signal The high potential of CLK1 to CLK8 is the same as the potential of the high power supply potential line VDD, and the low potential is It is assumed that the potential is the same as that of the low power supply line VSS.

[0376] In the driving method of the gate driver circuit 600 shown in FIG. 39, first, a start pulse SP is This causes the first transistor 611 and the fifth transistor 615 to be in a conductive state. In addition, since the reset signal RIN (output signal OUT7) is at a low potential, the sixth transistor The resistor 616 is non-conductive. Also, the clock signals CLK1 to CLK6 are at a low potential. Since the clock signals CLK7 and CLK8 are at a high potential, the fourth transistor 614 and The seventh transistor 617 is in a non-conductive state, and the third transistor 613 is in a conductive state.

[0377] At this time, the potential of the node FN1 is changed from the potential of the high potential power supply line VDD to the potential of the first transistor 6 The potential of node FN2 is the value obtained by subtracting the threshold voltage of 11 (VDD-Vth(611)). The seventh transistor 617 is turned on, and the eighth transistor Since the resistor 618 is non-conductive, the output signals OUT1 to OUT5 are equal to the clock signal It becomes the same low potential as CLK1 to CLK5.

[0378] Next, the clock signal CLK7 goes low, and the third transistor 613 is non-conductive. The other of the source and drain of the third transistor 613 and the fourth transistor A high potential is maintained at a node to which one of the source and drain of the transistor 614 is electrically connected. do.

[0379] Next, the clock signal CLK1 goes from low to high, and the The potential of the node FN1 rises by a voltage equivalent to the amplitude of the clock signal CLK1. As a result, the seventh transistor 617 is turned on, and the output signal OUT1 is at a high potential (clock The bootstrap is performed by outputting the potential of the clock signal CCLK1. The same thing happens when the clock signal after LK2 goes from low to high. The signal CLK8 goes to a low potential, but the first-stage shift register unit 601 does not receive the clock signal. The signal CLK8 is not used, so there is no change. Next, the clock signal CLK2 goes high. Then, the output signal OUT2 goes high. After that, the clock signal CLK1 goes low. The output signal OUT3 and the output signal OUT4 are output at a low potential. The same is true for UT4. Also, the clock signal CLK5 goes high, and the output signal OUT5 goes high. When the voltage becomes high, the set signal LIN of the second-stage shift register unit 601 becomes high. become.

[0380] In the first-stage shift register unit 601, when the clock signal CLK6 goes high, , the fourth transistor 614 is turned on. Next, the clock signal CLK5 goes low, The output signal OUT5 is at a low potential.

[0381] In addition, in the second-stage shift register unit 601, the set signal LIN (output signal OU T5) becomes a high potential, and the first transistor 611 and the fifth transistor 615 are turned on. In addition, since the reset signal RIN (output signal OUT12) is at a low potential, The transistor 616 of the sixth input is turned off. Since CLK6 to CLK8 are at a low potential and clock signals CLK4 and CLK5 are at a high potential, , the fourth transistor 614 and the seventh transistor 617 are in a non-conducting state, Transistor 613 becomes conductive.

[0382] At this time, the potential of the node FN1 is changed from the potential of the high potential power supply line VDD to the potential of the first transistor 6 The potential of node FN2 is the value obtained by subtracting the threshold voltage of 11 (VDD-Vth(611)). The seventh transistor 617 is turned on, and the eighth transistor Since the resistor 618 is non-conductive, the output signals OUT6 to OUT10 are equal to the clock signal The potential becomes the same low as that of the signals CLK1, CLK2, CLK6 to CLK8.

[0383] Next, the clock signal CLK4 goes low, and the third transistor 613 is turned off. The other of the source and drain of the third transistor 613 and the fourth transistor A high potential is maintained at a node to which one of the source and drain of the transistor 614 is electrically connected. can be.

[0384] Next, the clock signal CLK6 goes from low to high, and the The potential of the node FN1 rises by a voltage equivalent to the amplitude of the clock signal CLK6. As a result, the seventh transistor 617 is turned on, and the output signal OUT6 is at a high potential (clock Next, the clock signal CLK5 goes to low potential, but The second stage shift register unit 601 does not use the clock signal CLK5. Then, the clock signal CLK7 goes to a high potential, and the output signal OUT7 goes to a high potential. A potential is output.

[0385] At this time, in the first-stage shift register unit 601, a reset signal RIN (output signal The sixth transistor 616 is turned on, and the node FN2 The potential of the node FN2 becomes the potential of the high potential power supply line VDD. By turning on the transistor 612, the potential of the node FN1 becomes equal to that of the low potential power line VSS. The potential is reset.

[0386] In addition, in the second-stage shift register unit 601, the first-stage shift register unit It operates in the same manner as unit 601.

[0387] In other words, the set signal LIN of the m-th stage (m is a natural number) shift register unit 601 is , the output signal OUT5(m-1) of the (m-1)th shift register unit 601 is input. The reset signal RIN of the mth shift register unit 601 is The output signal OUT5(m+2) of the register unit 601 is input. The set signal LIN becomes a start pulse SP.

[0388] In addition, the shift register unit 602, which is a dummy stage, and the shift register unit 601 The shift register unit 602 is the same as the shift register unit 602. A reset signal RIN can be input to the final stage of unit 601.

[0389] In this embodiment, the overlap of the pulses of the clock signal and the next clock signal is called a pulse. Although it is set to 1 / 3 of the width, this is not limited to this. If it is less than 1 / 2 of the pulse width, how will it overlap? Also, the falling edge of a clock signal pulse and the rising edge of the next clock signal pulse may be The rising edge of the clock signal may be simultaneous with the falling edge of the next clock signal. When the rising edges of the pulses of the first stage shift register unit 6 The gate selection output period of 01 is from the rising edge (set) of the start pulse SP to the clock Since the period is until the rising edge (reset) of clock signal CLK6, it is used for periodic charge compensation. Only one clock signal is required.

[0390] Note that the structure described in this embodiment mode may be appropriately combined with structures described in other embodiments. It can be used.

[0391] (Embodiment 5) The semiconductor device according to one embodiment of the present invention includes a sensor ( For example, touch sensors that use capacitive, resistive, surface elastic, infrared, or optical technologies This is applied to radiological image detection devices capable of acquiring radiological images for medical use. In addition, the semiconductor device according to one embodiment of the present invention can be used in a variety of electronic devices (including gaming machines). The electronic device can be applied to a television device (including a television, Television receivers, computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, and personal digital assistants , audio playback devices, gaming machines (pachinko machines, slot machines, etc.), and game cabinets. An example of these electronic devices is shown in FIG.

[0392] FIG. 24A shows a table 9000 having a display section. A display unit 9003 is built into the housing 9001, and an image is displayed on the display unit 9003. It is possible to support the housing 9001 with four legs 9002. The housing 9001 also includes a power cord 9005 for supplying power.

[0393] The semiconductor device described in any of the above embodiments can be used for the display portion 9003. Therefore, the display quality of the display portion 9003 can be improved.

[0394] The display unit 9003 has a touch input function. By touching the display button 9004 displayed on the screen with a finger or the like, the screen can be operated or information can be input. It also allows communication with and control of other home appliances, It may also be used as a control device to control other home appliances by operating the screen. If a semiconductor device having a touch sensor function is used, the display portion 9003 can have a touch input function. It is possible.

[0395] In addition, the screen of the display unit 9003 can be fixed to the floor by a hinge provided in the housing 9001. It can also be placed vertically and used as a television set. A large-screen television set will take up a lot of free space, but it can be placed on a table. If the display unit is built into the device, the space in the room can be used more effectively.

[0396] FIG. 24B shows a television device 9100. A display unit 9103 is incorporated in a housing 9101, and an image is displayed on the display unit 9103. In this example, the housing 9101 is supported by a stand 9105. The configuration shown is as follows.

[0397] The television device 9100 can be operated using an operation switch provided on the housing 9101 or a separate remote control. This can be done by using a remote control operation device 9110. The channel and volume can be controlled by the 9109, and the display 9103 shows The remote control device 9110 can control the video. A display unit 9107 for displaying information output from the device 9110 may be provided.

[0398] A television device 9100 shown in FIG. 24(B) includes a receiver, a modem, and the like. The television device 9100 can receive general television broadcasts using a receiver. Furthermore, by connecting to a wired or wireless communication network via a modem, Either directional (from sender to receiver) or bidirectional (between sender and receiver, or between receivers, etc.) ) information communication is also possible.

[0399] The semiconductor device described in any of the above embodiments is used for the display portion 9103 and the display portion 9107. Therefore, the display quality of the television device can be improved. do.

[0400] FIG. 24C shows a computer 9200, which includes a main body 9201, a housing 9202, a display unit 9 203, keyboard 9204, external connection port 9205, pointing device 920 6, etc.

[0401] The semiconductor device described in any of the above embodiments can be used for the display portion 9203. Therefore, the display quality of the computer 9200 can be improved.

[0402] FIG. 25(A) and FIG. 25(B) show a tablet-type terminal that can be folded in two. 9631a, the tablet terminal is in an open state. 9631b, a display mode changeover switch 9034, a power switch 9035, a power saving mode It has a mode changeover switch 9036, a fastener 9033, and an operation switch 9038.

[0403] The semiconductor device described in any of the above embodiments includes a display portion 9631a and a display portion 9631b. Therefore, it is possible to improve the display quality of tablet devices. Cut.

[0404] A part of the display unit 9631a can be used as a touch panel area 9632a. By touching the operation keys 9638 displayed on the display unit 96, data can be input. In 31a, as an example, half of the area has a display function only, and the other half The display unit 96 has a touch panel function, but is not limited to this. The entire area of ​​the display unit 931a may have a touch panel function. The entire surface of 631a is made to display keyboard buttons to serve as a touch panel, and the display section 9631b is made to display It can be used as a display screen.

[0405] In addition, in the display unit 9631b, as in the display unit 9631a, The part of the touch panel can be the area 9632b of the touch panel. Touch the area where the mode display switch button 9639 is displayed with your finger or a stylus. A keyboard button can be displayed on the display portion 9631b.

[0406] In addition, the touch panel area 9632a and the touch panel area 9632b are simultaneously You can also use touch input.

[0407] A display mode changeover switch 9034 is used to change the display orientation, such as portrait or landscape. You can switch between black and white and color display. The switch 9036 is a switch that turns on and off when the tablet terminal is in use and is detected by a light sensor built into the tablet terminal. The brightness of the display can be optimized according to the amount of light. In addition to sensors, other detection devices such as gyros, acceleration sensors, etc. that detect tilt may be incorporated.

[0408] FIG. 25A shows an example in which the display area of ​​the display portion 9631b is the same as that of the display portion 9631a. However, there is no particular limitation, and one size may be different from the other size. The quality of the display may also be different. For example, one display panel may provide a higher resolution display than the other. It may also be used as a rule.

[0409] FIG. 25(B) shows the tablet terminal in a closed state. The tablet terminal includes a housing 9630 and a solar cell 9 25B, the charge / discharge control circuit 96 As an example of the 34, a configuration having a battery 9635 and a DC-DC converter 9636 is described below. This is shown.

[0410] In addition, since the tablet device can be folded in half, the case 9630 can be folded when not in use. Therefore, the display portions 9631a and 9631b can be protected. This makes it possible to provide a tablet device that is highly durable and reliable even when used for a long period of time.

[0411] In addition, the tablet terminals shown in Figs. 25(A) and 25(B) can be used in various Functions that display information (still images, videos, text images, etc.), calendars, dates or times A function to display the information on the display, and a function to operate the information displayed on the display by touch input or editing. It has touch input function, function to control processing by various software (programs), etc. It is possible.

[0412] The solar cell 9633 attached to the surface of the tablet device supplies power to the touch panel. The solar cell 9633 can supply the light to a display unit, a video signal processor, or the like. The battery 9635 can be efficiently charged by providing a light-emitting diode (LED) on one or both sides of the housing 9630. The battery 9635 may be a lithium ion battery. The use of the above has the advantage of enabling miniaturization.

[0413] The configuration and operation of the charge / discharge control circuit 9634 shown in FIG. A block diagram is shown in FIG. 25(C) and will be explained. FIG. 25(C) shows a solar cell 9633, a battery 9 635, DC-DC converter 9636, converter 9637, switches SW1 to SW3 , a display unit 9631, a battery 9635, a DC-DC converter 963 6. The converter 9637 and the switches SW1 to SW3 are configured to perform the charge / discharge control shown in FIG. 25(B). This corresponds to the circuit 9634 .

[0414] First, an example of operation when power is generated by the solar cell 9633 due to external light will be described. The power generated by the solar cell is converted to a voltage to charge the Battery 9635. The CDC converter 9636 steps up or steps down the voltage. When power is supplied from the solar cell 9633, switch SW1 is turned on and the converter The voltage is increased or decreased by a voltage converter 9637 to a voltage required for the display unit 9631. When no display is to be made on the display unit 9631, the switch SW1 is turned off and the switch SW2 is turned on. It is sufficient to configure it so that the power is turned on and the battery 9635 is charged.

[0415] The solar cell 9633 is shown as an example of a power generating means, but is not limited thereto. , and other power generation methods such as piezoelectric elements and thermoelectric conversion elements (Peltier elements) For example, the battery 9635 may be charged. A non-contact power transmission module that transmits and receives power and charges, or a combination of other charging methods This may also be configured.

[0416] Note that the structure described in this embodiment mode may be appropriately combined with structures described in other embodiments. It can be used. EXAMPLES

[0417] In this embodiment, a liquid crystal display device was manufactured using the semiconductor device of the first embodiment. The frame area of ​​the liquid crystal display device is evaluated.

[0418] As a comparative example, a liquid crystal display in which the conductive film 310c of the driving circuit portion does not overlap with the conductive film 304b is used. The liquid crystal display device shown in FIG. 26 includes a driving circuit portion including a conductive film 304b and a conductive The conductive film 310c is connected to the light-transmitting conductive film 316a. The conductive film 316a is formed through the opening 3 provided in the insulating film 305, the insulating film 306, and the insulating film 312. 67a, connecting at opening 367b.

[0419] FIG. 27 shows a layout diagram of the periphery of the opening. FIG. 27(A) shows a liquid crystal display device of a comparative example. FIG. 27(B) is a layout diagram of the periphery of the opening, in which the semiconductor device of the first embodiment is used. FIG. 2 is a layout diagram of the periphery of an opening of a liquid crystal display device.

[0420] The layout width around the opening of the liquid crystal display device of the comparative example was 21 μm. The layout width around the opening of the liquid crystal display device using the semiconductor device of the first embodiment is 15 μm. As a result, the conductive film 304b and the conductive film 310c were connected to the light-transmitting conductive film 31 When connecting at 6a, one opening (here, opening 364a) is used as in the first embodiment. The conductive film 304b, the conductive film 310c, and the light-transmitting conductive film 316a are connected only by the This allows the layout width to be reduced by 6 μm per opening, making it possible to narrow the frame of LCD displays. It is possible to achieve this.

[0421] Next, the two openings in the comparative example are changed to one opening in the first embodiment. The reduction rate of the frame area was calculated.

[0422] 28 is a layout diagram of a liquid crystal display device of a comparative example. The layout width of the drive circuit section is The total area was 1,850 μm. The total area including the protective circuit, signal lines, and sealing area was 2,646 μm. there were.

[0423] Furthermore, in the driving circuit section, the two openings as in the comparative example are opened as in the first embodiment. The areas where the mouth can be changed to one are surrounded by dashed lines in the figure.

[0424] In this embodiment, a total of nine locations can be changed to one opening, and the entire drive circuit section It can be reduced by 54μm (6μm x 9 places). Therefore, by doing as above The frame can be reduced by 2.04% (54μm÷2646μm×100%), and the LCD This enabled the display device to have a narrower frame. EXAMPLES

[0425] A liquid crystal display device was manufactured using the semiconductor device of the first embodiment. FIG. 45(A) shows a cross-sectional TEM image of the periphery of the opening of the liquid crystal display device using the semiconductor device of the first embodiment. FIG. 45(B) shows a cross-sectional TEM image of the periphery of the opening of the liquid crystal display device.

[0426] As shown in FIG. 45(A), the liquid crystal display device of the comparative example had voids in the insulating film. 5(B) is a gate electrode overlapping a source electrode or a drain electrode as in the first embodiment. By forming the insulating film in this manner, a light-transmitting conductive film is not formed on the insulating film. No voids are generated, and it has been confirmed that the coating properties of the film can be improved. Done. EXAMPLES

[0427] In this embodiment, a liquid crystal display device was manufactured using the driver circuit of the fourth embodiment. The frame area of ​​the liquid crystal display device is evaluated.

[0428] First, a liquid crystal display device was fabricated using the driving circuit of the fourth embodiment with the configuration shown in FIG. As a comparative example, one output per stage of the shift register unit as shown in FIG. A liquid crystal display device was fabricated using the configuration of FIG. 26 for a conventional driving circuit that outputs a signal. .

[0429] FIG. 43 shows a layout diagram of the drive circuit unit. FIG. 43(A) shows the layout of the drive circuit unit of the comparative example. FIG. 43(B) shows the layout of this embodiment, and the layout width is 1700 μm. FIG. 1 is a layout diagram of the driving circuit section, and the layout width is 1150 μm. By adopting the drive circuit of mode 4, the frame has been reduced by 32.24% (1700μm) compared to the conventional method. m-1150μm)÷1700μm×100%), the narrowing of the LCD We were able to frame it.

[0430] Similarly, the channel protection type transistor shown in the sixth modification of the first embodiment is added to the driving circuit of the fourth embodiment. A liquid crystal display device was manufactured using the transistor. As a comparative example, The conventional drive circuit outputs one output signal per shift register unit. A liquid crystal display device was manufactured using a channel protective transistor.

[0431] FIG. 44 shows a layout diagram of a drive circuit section different from the above. FIG. 44 is a layout diagram of the driving circuit part of the example, and the layout width is 1700 μm. (B) is a layout diagram of the driving circuit part of this embodiment, and the layout width is 1250 μm. By adopting the drive circuit of the fourth embodiment, the frame was reduced by 26.4 mm compared to the conventional method. It can be reduced by 7% ((1700μm-1250μm)÷1700μm×100%) This enabled the frame of the liquid crystal display device to be narrowed. EXAMPLES

[0432] In this embodiment, CA, an In-Ga-Zn oxide that can be used for liquid crystal displays, The characteristics of a transistor including an AC-OS film are evaluated.

[0433] The measurement was performed using a gate driver buffer with a channel length of 50 μm and a channel width of 100 μm. A transistor with a channel etch structure of 4 μm was used.

[0434] Next, the configuration of the transistor will be described.

[0435] The transistor has a gate electrode on a glass substrate and a gate electrode on the glass substrate and the gate electrode. an insulating film, an oxide semiconductor film on the gate insulating film, a source electrode in contact with the oxide semiconductor film, and A drain electrode, an oxide semiconductor film, a first insulating film on the source electrode and the drain electrode, a second insulating film on the oxide semiconductor film, The insulating film is connected to the source electrode or the drain electrode through an opening provided in the first insulating film and the second insulating film. and a pixel electrode electrically connected to the drain electrode.

[0436] The gate electrode is made of a 35 nm thick titanium film and a 200 nm thick copper film laminated thereon. The gate insulating film is a 50 nm thick silicon oxynitride film on a 400 nm thick silicon nitride film. The oxide semiconductor film is a 35-nm-thick In:Ga:Zn=1:1:1 The source and drain electrodes are In-Ga-Zn oxide films with a thickness of 5 A 400 nm thick aluminum film on a 0 nm thick tungsten film, The first insulating film is a 50 nm thick silicon oxynitride film. A silicon oxynitride film with a thickness of 400 nm is laminated on the silicon film. The pixel electrode is a silicon nitride film with a thickness of 110 nm. The indium tin oxide film is an indium tin oxide film having a thickness of 100 nm and a thickness of 100 nm.

[0437] The characteristics of the fabricated transistor are shown in Figure 46. The vertical axis in the figure represents the drain current ID [A]. The horizontal axis represents the gate voltage VG [V]. It was found that the above characteristics were obtained.

[0438] In addition, a transistor with a channel etch structure with a channel length of 50 μm and a channel width of 6 μm was A photodiode was fabricated and held at 60°C for 1 hour in a dark state with a gate potential of 30 V. Figure 47(A) shows the state of the transistor after the +BT test. The vertical axis in the figure represents the threshold voltage variation ΔVth [V], and the horizontal axis represents the test time. It is understood from Fig. 47(A) that the amount of change in the threshold voltage is small.

[0439] In addition, in the above transistor, the gate potential is set to 30 V in a dark state. A test in which the device is held at 60°C for 1 hour (+BT test) and a test in which the gate potential is - The test (-BT test) was repeated alternately at 30V and 60℃ for 1 hour. The results are shown in FIG. 47(B). The vertical axis in the figure represents the threshold voltage Vth [V], and the horizontal axis represents the The conditions are shown in Fig. 47(B). It can be seen that there is almost no fluctuation in the characteristics. [Explanation of symbols]

[0440] 101 Pixel section 102 Transistor 103 Transistor 104 Scanning line driving circuit 105 Capacitive element 106 Signal line driver circuit 107 Scan Lines 109 Signal Line 115 Capacitive Line 131_1 Transistor 132 Liquid crystal element 133_1 Capacitive element 301 pixels 302 Substrate 304a Conductive film 304b Conductive film 304c conductive film 305 Insulating film 305a Nitride insulating film 305b Nitride insulating film 305c Nitride insulating film 306 Insulating film 307 Oxide Semiconductor Film 308a Oxide semiconductor film 308b Oxide semiconductor film 308c conductive film 308d Oxide semiconductor film 309 Conductive Film 310a Conductive film 310b Conductive film 310c conductive film 310d conductive film 310e conductive film 310f conductive film 311 Insulating film 311a Insulating film 311b Insulating film 312 Insulating film 312a Insulating film 312b Insulating film 313 Insulating film 314 Insulating film 315 Conductive Film 316a Conductive film 316b Conductive film 316c Conductive film 316d Conductive film 317 Planarization film 318 Orientation Film 320 Liquid crystal layer 322 Liquid crystal element 324 Insulating Film 325 Conductive Film 326 Conductive Film 334a Low resistance area 334b Low resistance region 336 Multilayer film 336a Oxide semiconductor film 336b Oxide film 342 Substrate 344 Light-shielding film 346 Colored film 348 Insulating Film 350 Conductive Film 352 Orientation Film 360 Recess 362 Opening 362c opening 364a opening 364b opening 364c opening 367a opening 367b opening 370 areas 384a opening 384b opening 600 Gate driver circuit 601 Shift Register Unit 601a Shift Register Unit 602 Shift Register Unit 602a Shift Register Unit 603 Demultiplexer Circuit 604 Demultiplexer Circuit 605 Buffer 605a Buffer 611 Transistor 612 Transistor 613 Transistor 614 Transistor 615 Transistor 616 Transistor 617 Transistor 618 Transistor 619 Capacitive element 621 Transistor 622 Transistor 623 Transistor 624 Capacitive element 625 Transistor 9000 Table 9001 Case 9002 Legs 9003 Display section 9004 Display button 9005 Power Cord 9033 Fastener 9034 Switch 9035 Power Switch 9036 Switch 9038 Operation switch 9100 Television equipment 9101 Case 9103 Display section 9105 Stand 9107 Display section 9109 Operation key 9110 Remote control device 9200 Computer 9201 Main unit 9202 Case 9203 Display section 9204 Keyboard 9205 External connection port 9206 Pointing Device 9630 Case 9631 Display section 9631a Display section 9631b Display section 9632a area 9632b area 9633 Solar Cells 9634 Charge / discharge control circuit 9635 Battery 9636 DC-DC Converter 9637 Converter 9638 Operation key 9639 Button

Claims

1. A substrate; a first conductive film having a region in contact with an upper surface of the substrate; a second conductive film having a region in contact with the upper surface of the substrate; a first insulating film having a region located above the first conductive film and a region located above the second conductive film; a semiconductor film having a region located above the first insulating film; a third conductive film having a region in contact with an upper surface of the semiconductor film; a fourth conductive film having a region located above the first insulating film; a second insulating film having a region in contact with an upper surface of the third conductive film and a region in contact with an upper surface of the fourth conductive film; a fifth conductive film having a region located above the second insulating film; the first conductive film has a region that functions as a gate electrode; the first insulating film has a region that functions as a gate insulating film; the semiconductor film has a channel formation region; the third conductive film has a region functioning as one of a source electrode and a drain electrode, the fifth conductive film has a region in contact with an upper surface of the second conductive film; the fifth conductive film has a first region in contact with the first insulating film in a region overlapping with the second conductive film, the fifth conductive film has a second region in contact with the second insulating film in a region overlapping with the second conductive film; the first region is adjacent to the second region, the fifth conductive film has a region in contact with a side surface of the fourth conductive film in a region overlapping the second conductive film, The fifth conductive film has a region in contact with an upper surface of the fourth conductive film.

2. A substrate; a first conductive film having a region in contact with an upper surface of the substrate; a second conductive film having a region in contact with the upper surface of the substrate; a first insulating film having a region located above the first conductive film and a region located above the second conductive film; a semiconductor film having a region located above the first insulating film; a third conductive film having a region in contact with an upper surface of the semiconductor film; a fourth conductive film having a region located above the first insulating film; a second insulating film having a region in contact with an upper surface of the third conductive film and a region in contact with an upper surface of the fourth conductive film; a fifth conductive film having a region located above the second insulating film; the first conductive film has a region that functions as a gate electrode; the first insulating film has a region that functions as a gate insulating film; the semiconductor film has a channel formation region; the third conductive film has a region functioning as one of a source electrode and a drain electrode, the fourth conductive film has a region overlapping the second conductive film with the first insulating film interposed therebetween; the fifth conductive film has a region in contact with an upper surface of the second conductive film; the fifth conductive film has a first region in contact with the first insulating film in a region overlapping with the second conductive film, the fifth conductive film has a second region in contact with the second insulating film in a region overlapping with the second conductive film; the first region is adjacent to the second region, the fifth conductive film has a region in contact with a side surface of the fourth conductive film in a region overlapping the second conductive film, The fifth conductive film has a region in contact with an upper surface of the fourth conductive film.

3. In claim 1 or 2, the first insulating film contains nitrogen and silicon; The second insulating film comprises nitrogen and silicon.

4. In any one of claims 1 to 3, The first conductive film, the second conductive film, and the fifth conductive film contain indium, tin, and oxygen.

Images