Semiconductor Devices

Abstract

Semiconductor having a capacitor element with a high aperture ratio and capable of increasing charge capacity To provide a semiconductor device that achieves a narrow frame. A transistor on a substrate and a gate electrode of the transistor formed on the same surface a first conductive film formed on the same surface as a pair of electrodes of the transistor; and a second conductive film formed on the same surface as a pair of electrodes of the transistor. a first light-transmitting conductive film electrically connected to the first conductive film and the second conductive film; the second conductive film overlaps with the first conductive film with a gate insulating film of the transistor interposed therebetween. It shall be set up as follows.

Description

[Technical Field]

[0001] The present invention relates to an article, a method, or a manufacturing method. The invention relates to the 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 manufacturing method thereof. [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. It is made of silicon semiconductor such as silicon or polycrystalline silicon. Transistors using semiconductors are also used in integrated circuits (ICs).

[0003] In recent years, metal oxides that exhibit semiconductor properties have been used in transistors instead of silicon semiconductors. In this specification, metal oxides that exhibit semiconductor properties are referred to as oxides. We will 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 fabricated and used as a switching element for a pixel of a display device. Techniques have been disclosed (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-123861 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-96055 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 layer is formed of a conductive film having a light-shielding property.

[0007] In addition, in a liquid crystal display device, the larger the capacitance value of the capacitance element, the more the capacitance value of the capacitance element increases. In this case, 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 must be 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 decreases, and the display quality of the image deteriorates. Such a problem is particularly noticeable in high-resolution liquid crystal display devices.

[0009] Furthermore, there is 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 capacitor that has a high aperture ratio and can increase the charge capacity. Another object of the present invention is to provide a semiconductor device or the like having a quantum element. 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. It is possible to extract other issues from the drawings, claims, etc. [Means for solving the problem]

[0012] One aspect of the present invention is to provide a transistor on a substrate and a gate electrode of the transistor on the same surface. a first conductive film 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 the transistor. The semiconductor device is characterized by overlapping.

[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; and a third light-transmitting layer connected to the transistor and having a recess formed in the opening. and a conductive film.

[0014] The transistor has a gate electrode formed on a substrate and a gate electrode in contact with the gate electrode. 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 may contain In, Ga, or Zn. Includes. [Effects of the Invention]

[0017] According to one embodiment of the present invention, a capacitor element having a high aperture ratio and capable of increasing charge capacity can be provided. Furthermore, according to one embodiment of the present invention, a semiconductor device having a display defect can be manufactured. According to one embodiment of the present invention, a semiconductor device having a narrow frame can be manufactured. Therefore, a semiconductor device that has achieved high efficiency can be manufactured. [Brief explanation of the drawings]

[0018] [Figure 1] 1A and 1B are a block diagram and a circuit diagram illustrating one embodiment of a semiconductor device. [Figure 2] 1A and 1B are top views illustrating one embodiment of a semiconductor device. [Figure 3] 1A and 1B are cross-sectional views 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. [Figure 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] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 10] 1A and 1B are cross-sectional views 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] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 14] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 15] 1A and 1B are cross-sectional views 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] 1A and 1B are cross-sectional views illustrating one embodiment of a transistor. [Figure 19] 1A and 1B are cross-sectional views illustrating one embodiment of a transistor. [Figure 20] 1A and 1B are cross-sectional views illustrating one embodiment of a transistor. [Figure 21] 1A and 1B are cross-sectional views illustrating one embodiment of a transistor. [Figure 22] 1A and 1B are cross-sectional views illustrating one embodiment of a transistor. [Figure 23] 1A and 1B are diagrams showing ultrafine electron diffraction patterns of oxide semiconductors; [Figure 24] 1A to 1C illustrate electronic devices using a semiconductor device which is one embodiment of the present invention. [Figure 25] 1A to 1C illustrate electronic devices using a semiconductor device which is one embodiment of the present invention. [Figure 26] FIG. 10 is a cross-sectional view of a liquid crystal display device of a comparative example. [Figure 27] FIG. 10 is a layout diagram of the periphery of an opening in a liquid crystal display device of a comparative example. [Figure 28]FIG. 10 is a layout diagram of a liquid crystal display device of a comparative example. [Figure 29] FIG. 2 is a diagram illustrating an overall configuration of a gate driver circuit. [Figure 30] FIG. 2 is a diagram illustrating a shift register unit. [Figure 31] FIG. 2 is a diagram illustrating a shift register unit that is a dummy stage. [Figure 32] FIG. 1 is a diagram illustrating a demultiplexer. [Figure 33] FIG. 1 is a diagram illustrating a demultiplexer. [Figure 34] FIG. [Figure 35] FIG. 10 is a diagram illustrating another shift register unit. [Figure 36] FIG. 10 is a diagram illustrating a shift register unit that is another dummy stage. [Figure 37] FIG. 10 is a diagram illustrating another buffer. [Figure 38] FIG. [Figure 39] 10 is a timing chart of a shift register unit. [Figure 40] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 41] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 42] 1A and 1B are cross-sectional views illustrating one embodiment of a semiconductor device. [Figure 43] FIG. 3 is a layout diagram of a drive circuit section. [Figure 44] FIG. 3 is a layout diagram of a drive circuit section. [Figure 45] FIG. 1 is a diagram illustrating a cross-sectional TEM image of a liquid crystal display device. [Figure 46] 1A and 1B are diagrams illustrating characteristics of a transistor. [Figure 47] 1A and 1B are diagrams illustrating characteristics of a transistor. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the following description, and the embodiments and methods thereof may be modified without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications may be made to the design 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 embodiments and examples described below, the same parts or parts having similar functions In the case of parts, the same symbols or the same hatch patterns are used in common among different drawings, and the repetition The explanation of repetition will be omitted.

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

[0021] In addition, terms such as first, second, and third used in this specification are used interchangeably to avoid confusion of components. It is not intended to limit the number of items. The terms "second" or "third" can be used interchangeably to explain the present invention.

[0022] The functions of the "source" and "drain" are also different when the direction of the current changes 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 refers to the potential difference between two points, and potential refers to the electrostatic field at a certain point. This refers to the electrostatic energy (electrical potential energy) of a unit charge in a particle. However, in general, the potential difference between the 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, the term "potential" may be read as "voltage." , voltage may be read as potential.

[0024] In this specification, when an etching step is performed after a photolithography step, 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 The m scanning lines are arranged parallel or approximately parallel to each other and the potentials of which 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 has n signal lines 109 whose potentials are controlled by the matrix. The pixel array has a plurality of pixels 301 arranged in a square shape. The capacitor 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 signal line driver circuit 104 and the signal line driver circuit 106 may be collectively referred to as a driver circuit portion.

[0027] Each scanning line 107 is connected 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 of the rows. is m pixels 301 arranged in m rows and n columns, and m pixels 301 arranged in any one of the columns. 1. Both m and n are integers equal to or greater than 1. is n pixels 301 arranged in any row among the pixels 301 arranged in m rows and n columns. 1. The capacitance lines 115 are arranged parallel to the signal lines 109. In the case where the pixels 301 are arranged in m rows and n columns, one of the pixels 301 is arranged in m rows and n columns. The pixel array 301 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 is also included.

[0030] The potential of one of the pair of electrodes of the liquid crystal element 132 is set appropriately according to the specifications of the pixel 301. The orientation 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 included in each pixel 301. In addition, one of the pair of electrodes of the liquid crystal element 132 for each pixel 301 in each row may be applied. Alternatively, in the case of IPS mode or FFS mode, different potentials may be applied to the liquid crystal elements. One of the pair of electrodes of the terminal 132 can be connected to the capacitance line CL.

[0031] For example, the liquid crystal display device including the liquid crystal element 132 can be driven in 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 also be driven by ECB (Electron Beam Controlled) driving. 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 various liquid crystal elements and their driving methods 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 following. The liquid crystal that exhibits the blue phase has a response speed of 1 msec or less. 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, the source electrode and the drain electrode of the transistor 131_1 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 doing so, the write control circuit 100 has a function of controlling the writing of data signals.

[0034] One of the pair of electrodes of the capacitor 133_1 is connected to a wiring to which a potential is supplied (hereinafter, referred to as 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 set appropriately 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 IPS mode or FFS mode, one of the pair of electrodes of the capacitor 133_1 is a liquid crystal display. It is also possible to electrically connect it 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. 1B, the scanning line driver circuit 104 The pixels 301 in each row are selected sequentially by the transistor 131_1, and the data signal is outputted by turning on the transistor 131_1. 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 for each 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 type liquid crystal display device, reflective type liquid crystal display device, direct view type liquid crystal display device, projection type An example of a liquid crystal element is a device that modulates light by the optical modulation effect of liquid crystal. There is an element that controls the transparency or non-transparency. The element is composed of a pair of electrodes and a liquid crystal layer. The optical modulation effect of the liquid crystal is due to the electric field applied to the liquid crystal (horizontal electric field , 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 Discotic liquid crystal, thermotropic liquid crystal, lyotropic liquid crystal, low molecular weight liquid crystal, polymer liquid Crystal, polymer dispersed liquid crystal (PDLC), ferroelectric liquid crystal, antiferroelectric liquid crystal, main chain liquid crystal, side chain Examples include molecular liquid crystals and banana-shaped liquid crystals.

[0038] Furthermore, 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 which is a device having a display element, a light emitting device, etc. can be used. Light emitting devices, which are devices having optical elements and light emitting elements, can be used in various forms, or It can have various elements. Examples of a display element, a display device, a light-emitting element, or a light-emitting device LEDs (white LED, red LED, green LED, blue LED, etc.), transistors, transistors (transistors that emit light according to the 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 Modulation) Fairness modulation element, piezoelectric ceramic display, carbon nanotube Tubes, etc., change contrast, brightness, reflectivity, transmittance, etc. due to electromagnetic effects. An example of a display device using electron-emitting devices is a filter. Field Emission Display (FED) or Single 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 that 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 drawing). 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 the 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 103 includes a conductive film 304c that functions as a gate electrode, a gate insulating film (not shown in FIG. 2), and a gate insulating film 304b. First, an oxide semiconductor film 308b in which a channel region is formed on the gate insulating film; Conductive films 310d and 310e functioning as source and drain electrodes 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 the gate electrode of the transistor 103. , which also functions as a signal line, and a region overlapping with the oxide semiconductor film 308b of the transistor 103 In addition, in FIG. 2, the scanning lines are 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] 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 electrode. A light-transmitting conductive film 316b serving as a base electrode and a light-transmitting conductive film 316b provided over the transistor 103 That is, the capacitance element 105 is made up 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 such as an FFS mode, an IPS mode, or an MVA mode. Like the pixel electrodes to be used, the electrode may have a structure having slits or a comb-like shape.

[0045] In this way, since the capacitor 105 has light-transmitting properties, the capacitor 105 is large and can be placed in the pixel 301. Therefore, the aperture ratio can be increased, typically 55%. or more, preferably 60% or more, and the liquid crystal having increased charge capacity For example, in a high-resolution liquid crystal display device, the pixel surface Therefore, it is suitable for high resolution liquid crystal display devices. In this case, the amount of charge stored in the capacitor element is reduced. Since the capacitor 105 has a light-transmitting property, by providing the capacitor in the pixel, In this case, the aperture ratio can be increased while obtaining sufficient charge capacity. It is suitable for use in high-resolution liquid crystal display devices with a resolution of 200 ppi or more, and even 300 ppi or more. You can be there.

[0046] 2, the pixel 301 has a side parallel to the conductive film 304c that functions as a scanning line. In comparison, the side parallel to the conductive film 310d that functions 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 for an increase in aperture ratio. 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] Furthermore, 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 light sources such as backlights, and The power consumption can be reduced.

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

[0049] The liquid crystal display device described 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 and a conductive film 316b that controls alignment. The liquid crystal layer 320 and the conductive film 35 are formed by the alignment film 318 and the alignment film 352. 0. Note that 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 a liquid crystal element. The 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., arranged in It is also called an LCD 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 the 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 connected to the gate insulating film, and the channel region is formed on the insulating film. the oxide semiconductor film 308b, the conductive film 310 serving as a source electrode and a drain electrode, and The conductive film 310e forms the transistor 103. The oxide semiconductor film 308b is The insulating film 310d is formed on the gate insulating film 310e. 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 in the insulating film 314.

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

[0056] In the driver circuit section, the conductive film 304a and the conductive film 304c are formed at the same time. 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 as the light-transmitting conductive film 316b is a conductive film formed at the same time as the light-transmitting conductive film 316b. The connection is made with 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 openings provided in the insulating film 305 and the insulating film 306. The conductive film 316a having optical transparency is formed by the insulating film 312, the insulating film 314, the insulating film 305, and the The connection is made through an opening provided in the insulating film 306. 314 is a nitride insulating film.

[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 formed by being 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] The components of the display device shown in FIG. 3 will now be described.

[0060] Conductive films 304a, 304b, and 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 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 an SOI substrate, etc., and a semiconductor element is provided on such a substrate. The substrate 302 may be a glass substrate. In this case, 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 separation layer may be provided between the substrate 302 and the transistor. After completing a part or all of the element part on it, it is separated from the substrate 302 and mounted on another substrate. In this case, the transistor can be mounted on a substrate with poor heat resistance or a flexible substrate. It can also be reproduced on boards.

[0063] The conductive films 304a, 304b, and 304c may be made of aluminum, chromium, a metal element selected from copper, tantalum, titanium, molybdenum, and tungsten, or The metal element is formed by using an alloy containing the above metal elements or an alloy combining the above metal elements. In addition, it is possible to use a material selected from one or more of manganese and zirconium. A metal element may be used. It may have a single layer structure or a laminated structure of two or more layers. For example, aluminum containing silicon single-layer structure of the film, two-layer structure with titanium film laminated on aluminum film, titanium on titanium nitride film Two-layer structure with a tungsten film laminated on a titanium nitride film, two-layer structure with a tungsten film laminated on a titanium nitride film, Two-layer structure in which a tungsten film is laminated on a titanium film or a tungsten nitride film, 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 is also used in combination with titanium, tantalum, tungsten, molybdenum, and chromium. A film of an element selected from chromium, neodymium, and scandium, or an alloy film combining multiple elements; Alternatively, a nitride film may be used.

[0064] The conductive films 304a, 304b, and 304c are formed of indium tin oxide, 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 silicon oxide-added indium tin oxide In addition, a combination of the above-mentioned transparent conductive material and the above-mentioned metal element can be used. It can 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 In-based oxynitride semiconductor films, In-based oxynitride semiconductor films, metal nitride films (InN, ZnN, etc.), etc. These films have a work function of 5 eV or more, preferably 5.5 eV or more, and are Since the electron affinity is larger than that of oxide semiconductors, transistors using oxide semiconductors The threshold voltage of the transistor can be shifted to the positive side, resulting in a switching For example, when an In-Ga-Zn oxynitride semiconductor film is used, At least, the nitrogen concentration is higher than that of the oxide semiconductor film 308a and the oxide semiconductor film 308b. An In-Ga-Zn 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 substrate 301. The gate insulating film of the transistor and the gate insulating film of the transistor of the pixel portion 101 Possess the ability.

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

[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 stacked 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 it overlaps with the gate electrode and functions as a channel region of the transistor in the driver 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. 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 Preferably, the thickness is 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 and the conductive film 308b having light-transmitting properties are calculated by adding the above atomic ratios as an error. 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 c are formed on the gate insulating film (here, on the insulating film 306), but the impurity concentration is Specifically, the oxide semiconductor film 308 is different from the oxide semiconductor film 308a and the oxide semiconductor film 308b in that it has a higher transparency. The impurity concentration of the conductive film 308c having 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 or more, preferably 1 × 10 20 atoms / c m 3 More preferably, 5 × 10 20 atoms / cm 3 That's all. 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 doubled, 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 308b. 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 more than 1x10 -1 Less than double It is preferable that the concentration is 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, a Group 14 element is 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) to 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 Alkaline gold When metals and alkaline earth metals bond with an oxide semiconductor, they may generate carriers. The off-state current of the transistor may increase. a. Reducing the concentration of alkali metal or alkaline earth metal in the oxide semiconductor film 308b It is preferable that:

[0080] When nitrogen is contained in the oxide semiconductor film 308a and the oxide semiconductor film 308b, This generates electrons as carriers, increases the carrier density, and makes it easier to become n-type. Transistors using oxide semiconductors, which are widely used in semiconductors, tend to be normally on. Therefore, 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 formed 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 Carrier density is 1×10 17 pieces / cm 3 Less than 1 × 10 15 pieces / cm 3 Below, More preferably, 1×10 13 pieces / cm 3 Less than 1×10, more preferably 11 pieces / cm 3 Below The lower oxide semiconductor film is used.

[0082] However, the semiconductor characteristics and electrical characteristics (field effect) of the required transistors are not limited to these. It is sufficient to use an appropriate composition depending on the required properties (e.g., the 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, interatomic distance of 08b It is preferable to make the material have appropriate properties such as thickness, density, etc.

[0083] The oxide semiconductor films 308a and 308b are formed between 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. 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 fabricated. 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 oxide semiconductors, which are essentially highly pure intrinsic, 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 known as normally-on). In addition, it is possible that 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 device 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 off-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 little fluctuation in electrical characteristics and may be a highly reliable transistor. Note that it takes a long time for the charges trapped in the trap states of the oxide semiconductor film to disappear. The trap level density is A transistor in which a channel region is formed in an oxide semiconductor film with high thermal conductivity has unstable electrical characteristics. Impurities may include hydrogen, nitrogen, alkali metals, or alkaline earth metals. etc.

[0085] On the other hand, the light-transmitting conductive film 308c is formed of a nitride film 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 the 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 this case, hydrogen is bonded to oxygen in the oxide semiconductor film to generate electrons as carriers. As a result, the oxide semiconductor film has high conductivity and functions as a conductor. The oxide semiconductor film 308a and the oxide semiconductor film 308 The oxide semiconductor film 308a is made of the same material as the oxide semiconductor film b and has a high hydrogen concentration. The metal oxide having a higher conductivity than 308b is 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 have a non-single crystal structure, for example. The non-single crystal structure may be, for example, a CAAC structure, which will be described later. -OS(C Axis Aligned Crystalline Oxide Sem These include polycrystalline structures, microcrystalline structures (described below), or amorphous structures. 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. 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, such as a region of a single crystal structure, and a region of a single crystal structure. , amorphous structure region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single The mixed film may have two or more regions of any of the crystalline structure regions. , amorphous structure region, microcrystalline structure region, polycrystalline structure region, CAAC-OS region, single 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, and the conductive film 30 having light-transmitting properties may be In some cases, it is possible that 8c is not in contact with the insulating film 314.

[0089] Furthermore, 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 using 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] The liquid crystal display device described in this embodiment includes a capacitor and an oxide semiconductor film formed on the oxide semiconductor film of the transistor. A light-transmitting conductive film that functions as a pixel electrode is formed. It is used as the other electrode of the capacitor element. 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 using a light-transmitting conductive film. As a result, the area occupied by the capacitor 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 zinc. elemental metals consisting of zinc, molybdenum, silver, tantalum, or tungsten; or The alloy containing this as the main component is used as a single layer structure or a laminated structure. A single layer structure of aluminum film containing titanium, a two layer structure of titanium film laminated on aluminum film, Two-layer structure with titanium film laminated on stainless steel film, and copper-magnesium-aluminum alloy film Two-layer structure with copper film laminated, titanium film or titanium nitride film and An aluminum film or copper film is laminated on the silicon film, and then a titanium film or nitride film is laminated on top of that. Three-layer structure forming 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 There are three-layer structures in which a molybdenum film or a molybdenum nitride film is formed on the surface. 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, the frame Since the edges can be reduced, the area occupied by the driving circuit section 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 308b are Conductive film 308c, and conductive film 310a, conductive film 310b, conductive film 310c, and conductive film 310d An insulating film 312 and an insulating film 314 are formed on the conductive film 310e. is a material capable of improving interface characteristics with the oxide semiconductor film, similar to the insulating film 306. 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 stacking 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 has a composition containing more oxygen than nitrogen. A silicon nitride oxide film is a film that contains more nitrogen than oxygen. Refers to...

[0096] Furthermore, it is preferable that the insulating film 312a has a small number of defects. Therefore, the spin density of the signal appearing at g=2.001, which is due to the dangling bond of silicon, Degrees are 3 x 10 17 spins / cm 3 This is because the insulating film 312 If the defect density in a is high, oxygen will bond to the defects, and the insulating film 312a This is because the oxygen permeability decreases.

[0097] In addition, the insulating film 312a, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting film 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 defects in the conductive film 308c is 1×1 0 17 spins / cm 3 It is preferably below the lower limit of detection.

[0098] In the insulating film 312a, all of the oxygen that has entered the insulating film 312a from the outside is absorbed by the insulating film 312a. Some oxygen does not move to the outside of 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 to move 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 to the oxide semiconductor film 312b through the insulating film 312a. 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 308c. This can be done.

[0100] An insulating film 312b is formed so as to be in contact with the insulating film 312a. The oxide insulating film is formed using an oxide insulating film containing more oxygen than the oxygen required for the stoichiometric composition. An oxide insulating film containing more oxygen than that satisfying 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 DS analysis, the amount of oxygen desorbed, converted to oxygen atoms, was 1.0 x 10 18 atoms / cm 3 or more, preferably 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] Furthermore, it is preferable that the insulating film 312b has a small number of defects. Therefore, the spin density of the signal appearing at g=2.001, which is due to the dangling bond of silicon, Degrees are 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. Therefore, the defect density may be higher than that of the insulating film 312a.

[0103] The insulating film 314 is made of a blocker such as oxygen, hydrogen, water, alkali metal, alkaline earth metal, etc. By providing a nitride insulating film having a blocking 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 nitride oxide, aluminum nitride, Examples include aluminum oxide nitride.

[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 nitride, hafnium oxide, and hafnium oxide 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. That's fine.

[0105] In addition, a light-transmitting conductive film 316a and a light-transmitting conductive film 311b are formed over the insulating film 314. The light-transmitting conductive film 316a has an opening 364a (FIG. 6(C)). ) 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 formed on the insulating film 316a and functions as a pixel electrode of the pixel. 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 conductive film 304b and the conductive film 310c are connected by the conductive film 316a having the following structure: 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 films 316a and 316b are made 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 transparency such as indium zinc oxide and silicon oxide-doped indium tin 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 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 to reduce disclination by increasing the pretilt angle of the liquid crystal material. It is possible to do this.

[0109] Also, a colored film (hereinafter referred to as a colored 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, and for example, a liquid crystal display may be used. In some cases, such as when the display device is monochrome, the colored film 346 may not be provided.

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

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

[0112] An insulating film 348 is formed on the colored film 346. The insulating film 348 is formed by a planarizing method. The function of the colored film 346 is to prevent impurities contained therein from diffusing into 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 conductive film has a function as the other of the pair of electrodes of the liquid crystal element. 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 layer 350 .

[0114] In addition, the light-transmitting conductive film 316a, the light-transmitting conductive film 316b, 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 moisture and the like from entering from the inside, it is preferable that the insulating layer is in contact with an inorganic material.

[0115] In addition, the light-transmitting conductive film 316a, the light-transmitting conductive film 316b, and the conductive film 350 A spacer may be provided between the liquid crystal layer 320 and the substrate 300 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 shown in the liquid crystal display device shown in FIG. 4 to 7. Here, 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 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 etching the area not covered by the mask. (See Figure 4(A)).

[0119] The conductive films 304a, 304b, and 304c are typically formed by evaporation. 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 formed successively in a vacuum, impurities are easily removed. This is preferable because it prevents 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 The thin film can be formed by using ablation method or the like.

[0124] Next, the oxide semiconductor film 307 is processed into desired regions, whereby island-shaped oxide semiconductor films 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 the following method. A mask is formed on the region by a second patterning, and the region not covered by the mask is The formation can be achieved by etching. Examples of etching include dry etching and 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 308b are highly purified. The temperature of the heat treatment is typically 250 The temperature is set to 650°C or higher, 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 warpage and shrinkage of the substrate even in large area substrates. This improves yield.

[0126] The heat treatment can be performed using an electric furnace, an RTA device, or the like. Therefore, the heat treatment can be performed 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 the 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 1 ppm or less, preferably 10 ppb or less), or rare gases (argon, helium The above-mentioned nitrogen, oxygen, ultra-dry air, or rare gas may be added to the atmosphere of water. It is preferable that the material does not contain nitrogen, water, etc. Furthermore, 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 from the oxide semiconductor film, 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 semiconductor film 308b were 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. , a conductive film 310c, a conductive film 310d, and a 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 desired areas. 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 section can be reduced. In addition, the conductive film 316a having light-transmitting properties and the conductive film 310c can be formed 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 film 308b are The conductive film 308d, the conductive film 310a, the conductive film 310b, the conductive film 310c, and the conductive film 310d , an insulating film in which insulating films 311a and 311b are stacked 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 being exposed to the atmosphere. After the insulating film 311a is formed, the flow rate of the source gas is preferably adjusted without exposing the insulating film 311a to the atmosphere. The insulating film 311b is continuously formed by adjusting one or more of the pressure, the high frequency power, and the substrate temperature. By doing so, 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 transferred to the oxide semiconductor film 308a. 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 dioxide film placed in a vacuum-evacuated processing chamber of a plasma CVD apparatus. The substrate is maintained at 180°C or higher and 400°C or lower, preferably 200°C or higher and 370°C or lower, and processed. The 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 set to 100 Pa or more and 250 Pa or less, and high frequency power is applied to an 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 silicon-containing deposition gases include silane, disilane, and thiazol-2-ylsilane. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, Examples include nitrogen dioxide.

[0136] By using the above conditions, an oxide insulating film that transmits oxygen is formed as the insulating film 311a. Furthermore, 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 is placed in a vacuum-evacuated processing chamber of a plasma CVD apparatus. The substrate is kept at 280°C or higher and 400°C or lower, and raw material 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 processing 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 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 resistant 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 this case, 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, fluctuations in 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 this case, the oxide semiconductor film 308a and the oxide semiconductor film 308b are formed at a temperature higher than 220° C. 8b, part of oxygen contained in the oxide semiconductor film 308d is released, and oxygen vacancies are easily formed. In addition, 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 that reduce the amount of oxygen desorption, the amount of oxide desorption can be easily reduced. Reduce oxygen vacancies in the semiconductor film 308a, the oxide semiconductor film 308b, and the oxide semiconductor film 308d 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 311a are formed as follows. 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 the amount of silicon-containing deposition gas by 100 times or more, The hydrogen content in the insulating film 311a can be reduced. The amount of hydrogen mixed into the conductor 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 dioxide film placed in a vacuum-evacuated processing chamber of a plasma CVD apparatus. 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 at 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 or less, more preferably 0.25 W / cm 2 Over 0 .35W / cm 2 Silicon oxide film or oxynitride film is formed by supplying the following high frequency power. A silicon dioxide 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 silicon-containing deposition gases include silane, disilane, and thiazol-2-ylsilane. Examples of oxidizing gases include oxygen, ozone, nitrous oxide, Examples include nitrogen dioxide.

[0146] The insulating film 311b is formed under the conditions of high frequency irradiation at the above power density in a processing chamber under the above pressure. Supplying power increases the efficiency of decomposition of the source gas in the plasma, increasing the number of oxygen radicals. However, as the oxidation of the source gas progresses, the oxygen content in the insulating film 311b becomes lower than the stoichiometric composition. However, if the substrate temperature is the temperature at which the insulating film 311b is formed, Because the bond between silicon and oxygen is weak, some of the oxygen is released when heated. Oxidation that contains more oxygen than 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 formed on the oxide semiconductor film 308a. 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 films 308b and 308d The insulating film 311b can be formed using high frequency power with a power density.

[0147] In the film formation conditions for the insulating film 311b, the deposition property containing 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. Specifically, ESR measurements reveal that g=2.001 originates from silicon dangling bonds. The spin density of the signal appearing 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 is As a result, the reliability of the transistor can be improved. It can improve sexuality.

[0148] Next, a heat treatment is carried out. 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, 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℃, warping and shrinkage of the substrate can be prevented even in large area substrates. It is possible to reduce the amount of lead, thereby improving yield.

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

[0150] The heat treatment is carried out in a 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.) 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 semiconductor film 308c can be formed. The amount of oxygen vacancies contained 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 absorbed by the insulating film 311a and the insulating film 311b. When an insulating film 313 having a locking function is formed later and subjected to heat treatment, 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 film 308b. The oxide semiconductor film 308a is transferred to the oxide semiconductor film 308b and the oxide semiconductor film 308d. However, defects are generated 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 transistors and suppresses fluctuations in threshold voltage. It is possible.

[0153] 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 the element deficiency, the heat treatment does not have 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, and the conductive film are etched. The oxide semiconductor film 308d is damaged, and the oxide semiconductor film 308a and the oxide semiconductor film 3 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 the conductive film 304c, which function as gate electrodes However, the insulating film 311b contains more oxygen than satisfies the stoichiometric composition. By using an oxide insulating film containing a large amount of oxygen, the back channel side can be As a result, oxygen vacancies occurring in the oxide semiconductor film 308a and the oxide semiconductor film 308b can be repaired. Since defects contained in the compound semiconductor film 308b can be reduced, the reliability of the transistor can be improved. can be improved.

[0155] Note that the 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 by forming a fourth pattern in a desired region. A mask is formed by etching, and the area not covered by the mask is etched. The region overlapping with 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, an 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 containing impurities from the outside, such as oxygen, hydrogen, water, alkali metals, It is preferable to use a material that prevents alkaline earth metals and the like from diffusing into the oxide semiconductor film. and preferably contains hydrogen, and typically contains nitrogen, such as nitride. The insulating film 313 can 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 bonds with oxygen, generating electrons as carriers. The oxide semiconductor film 308d has high conductivity and becomes a 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. Preferably, the substrate temperature is 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 0.5°C or less. Oxygen is released from the oxide semiconductor used as the semiconductor film 308a and the oxide semiconductor film 308b. , the phenomenon of an increase in carrier concentration may occur, so this phenomenon does not occur The temperature.

[0162] Next, the insulating films 313, 312, 306, and 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 by a fifth patterning in a desired region. The mask is formed by etching the area not covered by the mask. This can be achieved (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, The method is not limited to this, and may be a wet etching method or a combination of a dry etching method and a wet etching method. A forming method combining 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 can be This can improve the coverage of the film 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 can be 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, thereby forming a light-transmitting conductive film. A light-transmitting conductive film 316a and a light-transmitting conductive film 316b are formed. The formation of the conductive film 316a and the conductive film 316b having light-transmitting properties is performed by the sixth patterning in a desired region. The mask is formed by etching the area not covered by the mask. This can be done (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 In other words, 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 introduced into the oxide semiconductor film 308d. silicon, boron, phosphorus, tin, antimony, rare gas elements, alkali metals, alkaline earth metals, etc. The conductivity of the oxide semiconductor film 308d may be increased by adding As a method of adding hydrogen, boron, phosphorus, tin, antimony, rare gas elements, etc. to 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 portion. 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. 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 and the alignment film 352.

[0173] First, a substrate 342 is prepared. The substrate 342 is made of the same material as 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 can be formed using various materials by a printing method, an ink-jet method, They are formed at desired positions by etching 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 acrylic resin, epoxy resin, or polyimide. By forming the insulating film 348, for example, the colored film 34 6 can be prevented from diffusing impurities into the liquid crystal layer 320. However, the insulating film 348 is not necessarily provided, and a structure without the insulating film 348 may be used. Good too.

[0177] Next, a conductive film 350 is formed over the insulating film 348 (see FIG. 8C). For example, 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 On the formed conductive film 350, an alignment film 318 and an alignment film 352 are formed. The alignment film 318 and 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. As a method, a dispenser method (dropping method) or a method in which the substrate 302 and the substrate 342 are bonded together and then Therefore, 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] It should be noted that various films such as metal films, semiconductor films, and inorganic insulating films disclosed in the embodiments are sputtering films. It can be formed by a deposition method or a plasma CVD method, but other methods, such as thermal CVD, are also possible. It may be formed by a chemical vapor deposition (Chemical Vapor Deposition) method. As an example of CVD, MOCVD (Metal Organic Chemical Vapor Deposition) por Deposition) method and ALD (Atomic Layer Deposition) You can also use the tion method.

[0182] The thermal CVD method is a film formation method that does not use plasma, so defects can occur due to plasma damage. This has the advantage that no further processing is required.

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

[0184] In addition, in the ALD method, the pressure inside the chamber is atmospheric or reduced, 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 this 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 An inert gas (argon, nitrogen, etc.) 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, Alternatively, instead of introducing an inert gas, the first source gas may be discharged by vacuum evacuation. 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 order until the desired thickness is achieved. By doing so, a thin film with excellent step coverage can be formed. The thickness can be precisely adjusted by changing the number of times the sequence is repeated. It is suitable for fabricating miniaturized 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. 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 of zinc is Zn(CH3)2. Triethylgallium (chemical formula Ga(C2H5)3) is used instead of trimethylgallium. Dimethyl zinc can also be replaced by diethyl zinc (chemical formula Zn(C2H5)2). It can also be done as follows.

[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 tetrachlorodibenzofuran (TDMAH) and the oxidizing agent is Two types of gases are used: tetrakisdimethylamidohafnium (Tetrakisdimethylamidohafnium) and ozone (O3). The chemical formula is Hf[N(CH3)2]4. Other material liquids include tetrakis(ethoxylated (ethylmethylamido) hafnium.

[0187] For example, when forming an aluminum oxide film using an ALD film forming device, 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 film forming device that uses ALD, Chlorodisilane is adsorbed onto the surface to be coated, removing the chlorine contained in the adsorbed material, 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 sequentially introducing BH gas and BH gas. The tungsten film is formed by simultaneously introducing B2H6 gas and H2 gas. 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 also be formed. 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, which does not contain H. In(CH3)3 gas Alternatively, In(C2H5)3 gas may be used instead of Ga(CH3)3 gas. Ga(C2H5)3 gas may be used instead of In(CH3)3 gas. Alternatively, n(C2H5)3 gas 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 section, and CD is a cross-sectional view of the pixel section.

[0193] In FIG. 3, the light-transmitting conductive film 316a is formed on the conductive film 304b in the opening 364a. 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] 9. In addition, in the region 370 surrounded by the broken line in FIG. 9, an insulating film 304b is formed on 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) 10c) is composed of a conductive film (here, a conductive film 316a having light-transmitting properties) This structure can also be applied to the terminals of semiconductor devices, and the contact resistance can be reduced in the same way. 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, as in FIG. 3, AB is a cross-sectional view of the drive circuit section, and CD is a cross-sectional view of the pixel section. is.

[0196] FIG. 10 shows the insulating film 314, the insulating film 312, the insulating film 306, and the insulating film 305 collectively etched. This differs from the cross-sectional view shown in FIG. 3 in that an opening is formed by chipping.

[0197] Here, the manufacturing method of the liquid crystal display device shown in FIG. 10 will be described with reference to FIGS. 4 and 5, 11 and 12. 12 will be used to explain.

[0198] As in the first embodiment, after the steps of FIGS. 4 to 5C, as shown in FIG. 3, 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 semiconductor film 308b are respectively The oxide semiconductor film 308b, the oxide semiconductor film 308d, the conductive film 310a, the conductive film 310b, and the conductive The conductive film 310c, the conductive film 310d, and the 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 pattern. 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 films 313, 312, 306, and 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 by a fifth patterning in a desired region. 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, thereby forming a light-transmitting conductive film. A light-transmitting conductive film 316a and a light-transmitting conductive film 316b are formed. The formation of the conductive film 316a and the conductive film 316b having light-transmitting properties is performed by the sixth patterning in a desired region. The mask is formed by etching the area not covered by the mask. This can be done (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 In other words, 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, just like FIG. 3. Figure.

[0207] FIG. 13 differs from the cross-sectional view shown in FIG. 3 in that a planarizing film 317 is provided below 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. and a region through which the backlight of the liquid crystal display device passes, i.e., a light-transmitting conductive film 3 The recessed portion provided in 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 conductive film 316b provided on 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 recesses is determined by 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 the function of a color filter. In the case where the pixel count is 1, for example, red pixels, blue pixels, and green pixels are set. A colored planarizing 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, preferably to the thickness of the insulating film 312 or more and 1000 nm or less. By making the thickness of the film 317 equal to or greater than that of the insulating film 312, the light-transmitting conductive film 316b The recesses can be filled with a planarizing film 317, and the 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 light-transmitting conductive film 316b which functions as a pixel electrode. The voltage becomes large and the power consumption becomes high. Therefore, the thickness of the planarization film 317 is set to 1500 nm or less is preferred.

[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 the 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 can be formed with a flat surface without being affected by the unevenness of the region where the film is to be formed. The planarization film 317 can be formed by spin coating, dip coating, slit coating, etc. When the method is used, after applying the composition, a mask is formed by patterning the desired area. The area not covered by the mask is then etched to form a planarization film 317 can be formed.

[0213] The liquid crystal display device shown in this modification has a light-transmitting conductive film 316 which functions as a pixel electrode. Since the planarizing film 317 is provided on the conductive film 316b, the planarizing 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 substrate 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] <Variation 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, as in FIG. 3, AB is a cross-sectional view of the drive circuit section, and CD is a cross-sectional view of the pixel section. Figure.

[0215] FIG. 14 shows the difference from FIG. 3 in that the thickness of the alignment film 318 is increased to reduce the unevenness of the pixel portion. This is different 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 in the conductive film 316b having light transmission property, which is generated 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 part of the recess 360 may be 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 can be in contact with the insulating film 305. In this case, there is no need to provide the opening 362 as shown in FIG. 16a, and it is possible to reduce the step on the surface of the light-transmitting conductive film 316b. Therefore, it is possible to reduce the alignment disorder of the liquid crystal material contained in the liquid crystal layer 320. Therefore, 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 Embodiment 1 will be described with reference to FIGS. 15 to 17. 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. Here, the first embodiment is used, but the present 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 protective 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, The transistor 102 is formed by forming the oxide semiconductor film 308a and the conductive film 310a. 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 on the conductive film 310a, the conductive film 310b, and the conductive film 310c as a protective film. It is established as:

[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 connected to the gate insulating film, and the channel region is formed on the insulating film. the oxide semiconductor film 308b, the conductive film 310 serving as a source electrode and a drain electrode, and 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. 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. The conductive film 310e is connected to the conductive film 310e in the opening.

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

[0225] In the driver circuit section, the conductive film 304a and the conductive film 304c are formed at the same time. 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 as the light-transmitting conductive film 316b is a conductive film formed at the same time as the light-transmitting conductive film 316b. The connection is made with 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. Furthermore, the insulating film 312 is formed with a larger amount of oxygen 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. The amount of oxygen vacancies in the oxide semiconductor film 308a and the oxide semiconductor film 308b can be reduced.

[0227] A method for manufacturing an element portion provided on a substrate 302 shown in the liquid crystal display device shown in FIG. This will be explained using FIGS. 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 gate insulating films. the oxide semiconductor film 305, the insulating film 306, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and 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, in the same manner as in the first embodiment, the insulating film 311a and the insulating film 311b are laminated. 11 is formed (see FIG. 16(A)).

[0230] Thereafter, similarly to 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 308. 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, so that 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 covered with the oxide semiconductor film 308a and the oxide semiconductor film 308b is 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)). (See reference). The conductive film 310a, the conductive film 310b, the conductive film 310c, the conductive film 310d, the conductive 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 film 310b are formed on the insulating film 305. 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, as in the second modification, the insulating film 313 is processed into a desired region, forming 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 the desired area. The mask can be formed by etching the area not covered by the mask (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 A light-transmitting conductive film is formed on the substrate 14. Next, the light-transmitting conductive film is formed in a desired region. By processing, a light-transmitting conductive film 316a and a light-transmitting conductive film 316b are formed. The light-transmitting conductive films 316a and 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 modification, 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 is formed between the insulating film 314. 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 having a light-transmitting property are used to form the capacitor 105. The electrode pair can be used as a pair of electrodes.

[0239] Furthermore, an organic insulating layer such as an acrylic resin, an epoxy resin, or a polyimide is applied to the insulating layer 312. An organic insulating film such as an acrylic resin film has high flatness and therefore has light-transmitting properties. Therefore, the step on the surface of the conductive film 316a can be reduced. 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. 42(A), 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 may be 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. The 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 same material as that of the insulating film 314 can be used.

[0241] (Embodiment 2) In this embodiment, modifications that 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, Aluminum nitride, aluminum oxynitride, etc. are used as the material for the base insulating film. 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, diffusion 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, The laminated structure of the insulating film that functions 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 this 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 O4c, typically hydrogen, nitrogen, alkali metals, or alkaline earth metals and the like 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 an oxygen-containing material having a stoichiometric composition, similar to the insulating film 312b. When the insulating film 306 and the oxide semiconductor film 307 are formed using an oxide insulating film containing as much oxygen as possible, This is more preferable because it is possible to further reduce the defect state density at the 308b interface. It's nice.

[0248] As shown in FIG. 18(A), the insulating film 305 is a nitride insulating film 305 with few defects. a and a nitride insulating film 305b having high hydrogen blocking properties are formed in this order from the conductive film 304c side. The insulating film 305 may be a nitride insulating film with 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 Therefore, hydrogen from the oxide insulating film 305a can be prevented from moving to the oxide semiconductor film 308b. Cut.

[0249] An example of a method for manufacturing the nitride insulating film 305a and the nitride insulating film 305b shown in FIG. 18(A) is as follows. 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 mixed gas of silane and nitrogen, and a layer with a low hydrogen concentration is formed. The silicon nitride film is a nitride insulating film 305b that is strong against hydrogen and can block hydrogen. This method of formation results in a film with few defects and good hydrogen blocking properties. The gate insulating film can be formed by stacking nitride insulating films having the above structure.

[0250] Alternatively, as shown in FIG. 18B, the insulating film 305 has a high blocking property for impurities. The nitride insulating film 305c, the nitride insulating film 305a with few defects, and the hydrogen-blocking The nitride insulating film 305b and the conductive film 304c are stacked in this order from the conductive film 304c side. The insulating film 305 is a nitride insulating film 305c having a high impurity blocking property. By providing the conductive film 304c, impurities, typically hydrogen, nitrogen, alkali metal, 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 the 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 changed to a mixture of silane and nitrogen, and the 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, it is possible to obtain a nitride insulating film having few defects and having an impurity blocking property. The insulating film 305 can be formed by laminating insulating films.

[0252] <Modification 3, Pair of Electrodes> In the liquid crystal display device described 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 be described. Here, the transistor 103 will be used for description.

[0253] The conductive films 310d and 310e provided in the transistor 103 described in Embodiment 1 as 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 The conductive material reacts with the oxide semiconductor film 308b, forming a region with many oxygen vacancies. In addition, a conductive material for forming the conductive films 310d and 310e on the oxide semiconductor film 308b is used. As a result, as shown in Figure 19, the oxide In the semiconductor film 308b, a low resistance film 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] The conductive film 310d and the conductive film 310e are formed by using the conductive material that easily reacts with oxygen and nitride. As a laminated structure with conductive materials that do not react easily 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 manufacturing method of 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 films 308a and 308b. The atmosphere may be oxygen, ozone, nitrous oxide, nitrogen dioxide, or the like. In the plasma treatment, the plasma generated without applying a bias to the substrate 302 side It is preferable to expose the oxide semiconductor films 308a and 308b to the light. , which does not damage the oxide semiconductor films 308a and 308b and does not supply oxygen. The oxide semiconductor film 308a and the oxide semiconductor film 308b can be supplied with the oxide semiconductor film 308a. The amount of oxygen vacancies can be reduced. a) Impurities remaining on the surface of the oxide semiconductor film 308b, such as halogens such as fluorine and chlorine, It is possible to remove such substances.

[0256] <Modification 5: Oxide Semiconductor Film> In the transistors 102 and 103 described in Embodiment 1, In this example, the oxide semiconductor film is used as the transistor 103. I will explain.

[0257] The transistor shown in FIG. 20 has a structure in which 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 36a and the insulating film 312a.

[0259] The oxide film 336b is composed of one or more of the 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 configured 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 an In-Ga oxide, an In-Zn oxide, an In-Mn oxide, or an In-GaAs 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 energy of 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 is smaller than that of the oxide semiconductor film 336a. The difference from the electron affinity is 0.05 eV or more, 0.07 eV or more, 0.1 eV or more, or 0 0.15eV or more and 2eV or less, 1eV or less, 0.5eV or less, or 0.4eV or less is.

[0261] The oxide film 336b contains In, which increases carrier mobility (electron mobility). This is preferable.

[0262] The oxide film 336b is 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 a strong bond with oxygen, so it can be easily bonded to 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 atomic %, 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 more. 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 In the case of Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf, the oxide semiconductor film 3 Compared with 36a, M (Al, Ti, Ga, Y, Zr, La) contained in the oxide film 336b , Ce, Nd, or Hf) is present in a large atomic ratio. The amount of the atoms contained in 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 In the case of Al, Ti, Ga, Y, Zr, La, Ce, Nd or Hf, oxide film 336b In:M:Zn=x1:y1:z1 [atomic ratio], and the oxide semiconductor film 336a is In:M :Zn=x2:y2:z2 [atomic ratio], y1 / x1 is larger than y2 / x2 Preferably, y1 / x1 is 1.5 times or more greater 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, the transistor using the oxide semiconductor film 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 of 2 or more and 8 or less), 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 is The error in each case is a variation of ±20% from the atomic ratio above. In the conductive film 336a, when the ratio of Zn is equal to or greater than Ga, CAAC-OS is easily formed. Very desirable.

[0267] The oxide film 336b is formed as an oxide semiconductor film when forming the insulating film 312b to be 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 Crystal) 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 of the following structures: a crystalline structure region, a polycrystalline structure region, a CAAC-OS region, and a single crystalline structure region. The mixed film may have, for example, an amorphous structure region, a microcrystalline structure region, or the like. two or more of the following: a region of a polycrystalline structure, a region of a CAAC-OS structure, and 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 trap states are formed due to defects, the trap states and the oxide semiconductor film 336a As a result, electrons flowing through the oxide semiconductor film 336a are transported to the trap states. This makes it possible to increase the on-state current of the transistor and also to In addition, when an electron is captured in the 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 can be reduced.

[0272] In addition, the oxide film 336b can block impurities from the outside. The amount of impurities that migrate from the oxide semiconductor film 336a to the oxide semiconductor film 336a can be reduced. For these reasons, the oxide semiconductor film 336a is less likely to have oxygen vacancies. It is possible to reduce the impurity concentration and oxygen vacancy in the silicon substrate.

[0273] Note that the oxide semiconductor film 336a and the oxide film 336b are not simply stacked. <Continuous junction (here, specifically, a structure in which the energy of the bottom of the conduction band changes continuously between each film) ) is formed at the interface of each film. The layer structure is such that there are no impurities that would form defect levels like the center. Impurities are mixed 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 being exposed to the atmosphere. Each chamber in the sputtering device 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 pumping (5×10 -7 Pa~1×10 -4 It is preferable to Alternatively, a turbomolecular pump and a cold trap can be combined to separate the chamber from the exhaust system. It is preferable to prevent the backflow of gases, especially gases containing carbon or hydrogen, into the bar. 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 formed between the insulating film 306 and the oxide semiconductor film 336a. In this case, the insulating film 306 and the oxide semiconductor film 36b 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 will be used for explanation.

[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 multilayer 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 has an oxide film 336b formed on the oxide semiconductor film 336a. The insulating film 312a functions as a channel region. An oxide film 336b is formed so as to contact the insulating film 312a. That is, 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 semiconductor film 336a is in contact with the oxide semiconductor film 336b, the semiconductor film 336a is in contact with the oxide semiconductor film 336b. 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 films 310d and 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 generated by the inclusion of constituent elements of the oxide semiconductor 312a and the insulating film 312b are This can prevent the oxide film 336a from being formed near the interface between the oxide film 336b. The transistor shown in the modification achieves both an improvement in on-state 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, A plurality of gate electrodes can be provided that 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, insulating films 305 and 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. and conductive films 310d and 310e 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 312e, an insulating film 312a and an insulating film 312b are stacked. 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 with the oxide semiconductor film 308b interposed therebetween. 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. This is preferable because it makes it possible to reduce the number of steps.

[0284] The transistor 103 in this modification has a conductive film 308b facing the oxide semiconductor film 308a. 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 can be controlled. It can be controlled.

[0285] In addition, the structures and methods shown in this embodiment may be used in conjunction with structures shown in other embodiments and examples. and methods can be used in appropriate combination.

[0286] (Embodiment 3) In this embodiment, a transistor included in the semiconductor device described in the above embodiment is In the figure, the oxide semiconductor film 308a, the oxide semiconductor film 308b, and the light-transmitting conductive film 3 08c and one embodiment applicable to the multilayer film 336. Although the description will be given using an oxide 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 include semiconductor films, CAAC-OS films, etc.

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

[0290] The microcrystalline oxide semiconductor film is made up of, for example, microcrystals (nanocrystals) with a size of 1 nm or more and less than 10 nm. Therefore, a microcrystalline oxide semiconductor film has a higher crystallinity than an amorphous oxide semiconductor film. The atomic arrangement is highly regular. Therefore, the microcrystalline oxide semiconductor film has a higher atomic regularity than the amorphous oxide semiconductor film. It has the advantage of having a lower defect level density than silicon.

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

[0292] The CAAC-OS film was observed under a transmission electron microscope (TEM). When observed under a tron ​​microscope, clear boundaries between the crystalline parts are 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 observed, it can be confirmed that metal atoms are arranged in layers in the crystalline part. Each layer of the CAAC-OS film is formed on a surface (also called a surface to be formed) or on a concave surface of the upper surface. The shape reflects the 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 approximately perpendicular to the sample surface (plane T EM observation reveals that metal atoms are arranged in triangular or hexagonal shapes in the crystalline region. 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 this is the case.

[0296] X-ray diffraction (XRD) of the CAAC-OS film When structural analysis is performed using this device, for example, CAAC-OS with InGaZnO4 crystals can be seen. In the out-of-plane analysis of the film, the diffraction angle (2θ) peaks 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 the direction is roughly vertical.

[0297] On the other hand, the in-p X-rays incident on the CAAC-OS film are perpendicular to the c-axis. In the Lane analysis, a peak may appear around 2θ of 56°. The crystal structure of InGaZnO4 is composed of a single crystal of InGaZnO4. 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 2θ. Even when the φ is fixed at around 56° and scanned, no clear peak appears.

[0298] From the above, it can be concluded 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 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 treatment such as a heat treatment. As described above, the c-axis of the crystal is aligned with the surface on which the CAAC-OS film is to be formed. Therefore, 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 normal vector of the face or top surface.

[0300] Furthermore, the crystallinity of the CAAC-OS film may not 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 to be formed. When impurities are added to the AC-OS film, the crystallinity of the region where the impurities are added changes, and the Regions of differing crystallinity may be formed.

[0301] In addition, the out-of-plane structure of the CAAC-OS film with InGaZnO4 crystals In the analysis by the NMR method, in addition to the peak at 2θ near 31°, a peak also appeared at 2θ near 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in part of the CAAC-OS film. The CAAC-OS film contains crystals that do not have crystalline structure. It is preferable that the peak is exhibited at 2θ of about 36° and that the peak is not exhibited at 2θ of about 36°.

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

[0303] In addition, in the case of CAAC-OS films, 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 resulting 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-forming 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-forming 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-forming 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-forming surface when CAAC-OS is formed or the normal vector of the surface. 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 to form an oxide semiconductor film with a film-forming temperature of 100°C or higher and 450°C or lower so that the c-axis of the crystal part included in the oxide semiconductor film forms a crystal part aligned in a direction parallel to the normal vector of the film-forming surface or the surface normal vector. [[ID=​The second method is to form a thin oxide semiconductor film and then heat it at a temperature of 200°C to 700°C. By the heat treatment, the c-axis of the crystal part included in the oxide semiconductor film is aligned with the normal vector of the surface where the oxide semiconductor film is formed. This is a method for forming crystals aligned in a direction parallel to the normal vector of the crystal or surface.

[0310] The third method is to deposit a thin oxide semiconductor film as a first layer, and then heat the film at 200°C or higher for 700°C. By performing heat treatment at 0.5°C or less and then forming a second oxide semiconductor film, The c-axis of the crystal part included in the conductive film is the normal vector of the surface on which it is formed or the normal vector of the surface. This is a method for forming crystals aligned in parallel directions.

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

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

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

[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 impurity concentration (hydrogen, water, carbon dioxide, nitrogen, etc.) present in the film formation chamber can be In addition, the impurity concentration in the deposition gas can be reduced. Film formation at -80°C or lower, preferably -100°C or lower, and more preferably -120°C or lower Gas is used.

[0315] In addition, by increasing the heating temperature of the surface to be film-formed (for example, the substrate heating temperature) during film formation, Specifically, the temperature of the surface on which the film is to be formed is 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 deposited on the surface, migration occurs on the surface. The sputtering particles adhere to the surface on which the film is to be formed, although this differs depending on the type of oxide. , the diameter (circle equivalent 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 approximately 10 nm or less. 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. This can suppress the formation of amorphous phases.

[0317] In addition, the sputtering target is sputtered using oxygen or argon cations. By doing so, if the flat sputtering particle is a hexagonal column, the hexagonal surface Positive charges can be applied to the corners of the hexagonal surface. 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 the flat sputtered particle to have a positive charge, a direct current ( It is preferable to use a DC power supply. However, it is also possible to use a radio frequency (RF) power supply or an alternating current (AC) power supply. However, the RF power supply is not suitable for sputtering equipment capable of depositing films on large-area substrates. In addition, DC power is preferable to AC power for the following reasons: It is possible.

[0319] When an AC power supply is used, adjacent targets alternately switch between cathode and anode potentials. If the flat sputtering particles are positively charged, they will repel each other. However, when using an AC power source, there is a momentary There is a time when no electric field is applied to the sputtering particle, and the charge on the plate-shaped sputtering particle The structure of the sputtered particles may be destroyed. 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 can be reduced. The oxygen ratio in the film forming gas is 30% by volume or more, preferably 100% by volume or more. Expressed as volume %.

[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. After that, it is heat-treated at a temperature between 1000℃ and 1500℃ to form polycrystalline In-G The target is a α-Zn compound. The pressure treatment is performed while cooling (or cooling naturally). The reaction may be carried out from the start or while heating. 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 type of powder and the mixture The ol number ratio may be changed as appropriate depending on the sputtering target to be produced.

[0323] By using the 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. may have.

[0325] In polycrystalline oxide semiconductors, for example, crystal grains can be confirmed in TEM observation images. Crystal grains contained in a polycrystalline oxide semiconductor can be seen in, for example, a TEM image. , 2nm to 300nm, 3nm to 100nm, or 5nm to 50nm In addition, polycrystalline oxide semiconductors often have a grain size of 100 μm or less in size, as seen in TEM images. In some cases, the boundaries between the amorphous portion and the crystal grains, and the boundaries between the crystal grains, can be confirmed. In polycrystalline oxide semiconductors, for example, grain boundaries can sometimes be confirmed in TEM observation images.

[0326] The polycrystalline oxide semiconductor has, for example, a plurality of crystal grains, and the crystal grains have a directional orientation. In addition, the polycrystalline oxide semiconductor may be analyzed by, for example, an XRD device. 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 indicating the orientation is at a peak near 31°, or In some cases, multiple peaks indicating several orientations appear. For example, spots may be observed in the electron diffraction pattern.

[0327] Polycrystalline oxide semiconductors have high crystallinity and therefore may have 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 the grain boundaries. In addition, the grain boundaries of polycrystalline oxide semiconductors become defect states. Since the polycrystalline oxide semiconductor can be a carrier generation source and a trap state, The transistor using CAAC-OS for the channel region is In all cases, the electrical characteristics may fluctuate significantly, resulting in a transistor with low reliability.

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

[0329] <Microcrystalline oxide semiconductor> In the microcrystalline oxide semiconductor, for example, crystal parts can be clearly seen in the observation image by TEM. The crystal part contained in the microcrystalline oxide semiconductor may have a size of, for example, 1 nm or more. They are often less than 100 nm in size, or between 1 nm and 10 nm in size. 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 Oxide Semiconductor). nc-OS is also called TE In the observation image by M, the boundary between the crystalline parts may not be clearly visible. For example, nc-OS does not have clear grain boundaries in TEM images, so impurities In addition, since nc-OS does not have clear grain boundaries, defects are unlikely to occur. The level density is not high. In addition, the nc-OS does not have a clear grain boundary, 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 or more and 10 nm or less). In addition, the nc-OS may have periodic atomic arrangements, for example, between crystalline parts. There is no regularity between the atoms, so there is no periodicity in the atomic arrangement macroscopically, or there is no 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, peaks indicating orientation may not be detected. The electron beam has a beam diameter larger than the target (for example, 20 nm or more, or 50 nm or more). In the electron diffraction pattern used, a halo pattern may be observed. The OS is, for example, 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 diameter or less, spots were observed. In addition, the electron 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 nc-OS. Here, 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 case, 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 Figure 23(B). A circular area of ​​high brightness is observed, and multiple spots are observed within the area. You can see that this is possible.

[0332] nc-OS has periodic atomic arrangement in microscopic regions, which makes it 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 derived by the constant photocurrent measurement method (CPM) is preferably less than 1 / cm. Kuha 5 x 10 -1 / cm, more preferably less than 5 × 10 -2 / cm or less.

[0333] Therefore, the carrier density of nc-OS may be higher than that of CAAC-OS. Oxide semiconductors with high carrier density can have high electron mobility. A transistor using an -OS for the channel region can have high field-effect mobility. In addition, the nc-OS has a higher defect density than the CAAC-OS, which increases the trap density. Therefore, the transistor using nc-OS for the channel region 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 large 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 in an oxygen-containing atmosphere at a temperature of from room temperature to 75°C, preferably from room temperature to 50°C. 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 contains microcrystalline regions. This can be done.

[0335] A microcrystalline oxide semiconductor film has stable physical properties by reducing oxygen vacancies. In particular, when a semiconductor device is manufactured using a microcrystalline oxide semiconductor film, The oxygen vacancies in the microcrystalline oxide semiconductor film act as donors, and carriers are released 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 with reduced defects, it is possible to improve reliability. Therefore, a high-quality semiconductor device can be obtained.

[0336] In a microcrystalline oxide semiconductor film, oxygen vacancies occur when the oxygen partial pressure in the film-forming atmosphere is increased. More specifically, the oxygen partial pressure in the film formation atmosphere is preferably 33%. It is preferable that the above is set.

[0337] Note that a target used for forming the microcrystalline oxide semiconductor film by a sputtering method The same target and manufacturing method as those for CAAC-OS can be used.

[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 in some applications. For example, nc-OS can be formed by a film formation method such as sputtering using an AC power source. The sputtering method using an AC power supply is suitable for forming a film on a large substrate with high uniformity. Therefore, it is possible to develop a semiconductor device having a transistor using nc-OS for the channel region. The device can be manufactured with high productivity.

[0339] <Amorphous oxide semiconductor> An amorphous oxide semiconductor has, for example, a disordered atomic arrangement and does not have a crystalline portion. Amorphous oxide semiconductors have an amorphous state like quartz, and have regular atomic arrangement. Can't see it.

[0340] In the amorphous oxide semiconductor, for example, crystalline 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 peak indicating the orientation is not detected, the amorphous oxide semiconductor may not be For example, a halo pattern may be observed in the electron diffraction pattern. For example, in the case of a compound semiconductor, no spots can be observed in the ultrafine electron diffraction pattern. -patterns may be observed.

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

[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 they are difficult to fabricate as CAAC-OS or nc-OS. 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 may Therefore, normally-on electrical characteristics are required. Amorphous oxide semiconductors can be suitably used for transistors that use amorphous oxide semiconductors. The density of trap states may also be high due to the high density of states. Transistors using conductors in the channel region have been developed using CAAC-OS and nc-OS. Compared to transistors used in the semiconductor industry, these transistors have large fluctuations in electrical characteristics and are less reliable. However, amorphous oxide semiconductors contain a relatively large amount of impurities when formed by a film formation method. Since it can be formed by the method, it is easy to form and is preferably used depending on the application. For example, spin coating, sol-gel, dipping, spraying method, screen printing method, contact printing method, inkjet printing method, roll coating method Alternatively, the amorphous oxide semiconductor may be formed by a film formation method such as mist CVD. A semiconductor device having a transistor using an amorphous oxide semiconductor for a channel region has high productivity. It can be made taller.

[0345] Note that, for example, the density of an oxide semiconductor increases when the number of defects is small. For example, when the crystallinity is high, the density is high. For example, a single-crystal oxide semiconductor, such as CAAC-OS In addition, for example, the CAAC-OS has a higher density than a microcrystalline oxide semiconductor. In addition, for example, polycrystalline oxide semiconductors may have a higher density than microcrystalline oxide semiconductors. 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] (Fourth embodiment) 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 this embodiment is a shift register unit and an electric and n signal lines (n is a natural number equal to or greater than 4). The shift register unit is electrically connected to one or more of the n signal lines, and The plexer circuit is electrically connected to one or more (n-3) or less of the n signal lines. The driving circuit is characterized by the above.

[0348] Another aspect of this embodiment is a circuit including m (m is a natural number equal to or greater than 3) shift registers. 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 equal to or greater than 4) are provided, and m shift registers are provided. Each of the signal 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 electrically connected to the subsequent shift register unit The driving circuit is characterized in that one is input.

[0349] In addition, another aspect of this embodiment is a shift register unit and a demultiplexer circuit. and n signal lines (n is a natural number equal to or greater than 4). a first transistor to a sixth transistor; The transistor has one of its source and drain electrically connected to a high power supply potential line, and the other of its source and drain The other input is connected to one of the source and drain of the second transistor and the demultiplexer circuit. a second transistor having a gate electrically connected to the set signal line and a gate electrically connected to the set signal line; 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 drain 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 potential 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. and a gate is 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 the 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 its source and drain electrically connected to a 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. and each of the a buffers is electrically connected to one of the n different signal lines. a plurality of buffers electrically connected to each other, each of the buffers 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) electrically connected to each shift register unit 601 P (also called DEMUX) 603, and the shift register unit 602 are electrically connected 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 the first transistor 612, and a set signal LIN is input to the gate of the second transistor 612. 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 potential line VDD. The other of the source and drain of the third transistor 613 is connected to the fourth transistor The gate of the third transistor 613 is connected to 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 , connected to the low power supply line VSS, and the gate of the fifth transistor 615 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, and the reset signal RIN is input to the gate of the sixth transistor 616. 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 referred to 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 616 The part where one of the source and drain of the transistor 616 is electrically connected is referred to as a node FN2. It is called.

[0353] In addition, the shift register unit 601 in the 8a+1th stage (a is 0 or a natural number) has a clock Clock signals CLK6 and CLK7 are input, and the clock signal CLK6 is output from the 8a+2nd stage (a is 0 or a natural number). The soft register unit 601 receives the clock signals CLK3 and CLK4. 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+5 stage (a is 0 or a natural number) is input to the shift register unit 601, which receives the 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 clock signals CLK4 and CLK5 are input to the shift register unit 601 (a natural number). The 8(a+1)th stage (a is 0 or a natural number) shift register unit 601 has the following: 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 signal LIN and clock signals (here, CLK3 and CLK4) are input. An example of the circuit configuration is shown in FIG. 31(B). The shift register unit 602 is 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 the first transistor 612, and a set signal LIN is input to the gate of the second transistor 612. 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 the high power supply potential 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 clock signal CLK4 is input to the gate of the third transistor 613. 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 of the second transistor 612 is The electrically connected portion is called a node FN1. 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 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) An example of a specific circuit configuration is shown in FIG. 32(B). 33(B) shows the demultiplexer circuit 603 and the demultiplexer circuit 604. has a buffer (BUF) 605.

[0357] An example of a specific circuit configuration of the buffer 605 is shown in FIG. 34. One of the source and drain of the clock signal CLK (clock signals 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 capacitor 618 is connected to a node FN2.

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

[0360] When initializing the shift register unit, input the reset signal RES pulse, The transistor 623 is turned on, and the potential of the node FN2 is equal to the potential of the high-potential power supply line VDD. In addition, the potential of the node FN2 changes the voltage of 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 supply 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 configured as a transistor as shown in FIGS. 37(A) and 37(B). The buffer 605a may be replaced with a buffer 605b provided with a capacitor 625 and a capacitor 619.

[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 gate of another transistor The previous embodiment is 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 signal is input to a demultiplexer circuit 603, which outputs an output signal OUT OUT1 to OUT5 are output.

[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, keeping the output at a low voltage. However, the cutoff current (gate voltage When the drain current (flowing when the voltage is 0V) is large, the charge on node FN2 flows into the fifth transistor. Since the charge leaks through the capacitor 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. Note that 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) until the rising edge of the clock signal CLK7. Therefore, the timing of the gate selection output period and the periodic charge replenishment must not overlap. do.

[0366] In addition, in the first stage shift register unit 601, where is the clock signal CLK8? This clock signal also has a timing that is important for the periodic charge compensation. 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 clock signal CLK3 and the clock signal CLK4 are supplied to the output circuit 603. 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 the first stage of the unit, five clock signals are input to a demultiplexer circuit 603, which demultiplexes the five clock signals. The diplexer circuit 603 outputs five output signals, and the other two clock signals are: It functions to periodically replenish the charge and is input to the shift register unit 601. Furthermore, 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 CLK1 and CLK2 are input to demultiplexer circuit 604, and demultiplexer circuit 60 4 outputs the output signals DUMOUT1 and DUMOUT2. The clock signals CLK3 and CLK4 has the function of periodically replenishing the charge.

[0370] In addition, in this 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 used to transmit the clock signal. By connecting them, n-3 output signals can be output, and the larger n is, the more closely it is affected by the output. The ratio of signal lines transmitting 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, The area occupied by the gate driver circuit 600 is reduced, allowing the width of the gate driver circuit 600 to be narrowed. .

[0372] Here, a brief description will be given of the narrowing of the frame of the gate driver circuit 600. 38(A) is a block diagram of a conventional gate driver circuit, and FIG. 38(B) is a block diagram of the gate driver circuit of this embodiment. FIG. 1 is a block diagram of a driver circuit.

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

[0374] The gate driver circuit of this embodiment has a shift register, which is different from the conventional gate driver circuit. The horizontal layout width can be reduced per stage of the star unit. The vertical layout width is The amount of increase in the buffer BUF (here, five times the previous amount) increases, but the cost of the gate driver circuit Therefore, the horizontal layout width per stage of the shift register unit can be reduced. This makes it possible to achieve a narrower frame. The number of signal lines CLK_LINE will increase compared to the past, but The load capacitance per 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 width of the signal line is narrowed to reduce the layout width. Therefore, even if the number of signal lines 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, the set signal LIN, the reset signal RIN, and the 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 potential line VSS.

[0376] In the driving method of the gate driver circuit 600 shown in FIG. 39, first, a start pulse SP is The potential becomes high, and the first transistor 611 and the fifth transistor 615 are turned on. Also, 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 VDD-Vth(611). The potential of the low potential power supply line VSS is reached, the seventh transistor 617 is in a conducting state, 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 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. 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 potential of the clock signal CLK1 is output. 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 receives the clock signal The signal of clock signal CLK8 is not used, so there is no change. Next, clock signal CLK2 is at a high potential. Then, the output signal OUT2 goes high. The output signal OUT1 is set to a low potential. The same applies to UT4. Also, the clock signal CLK5 goes high, and the output signal OUT5 goes high. When the potential becomes high, the set signal LIN of the second-stage shift register unit 601 becomes high. becomes.

[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 high potential, and the first transistor 611 and the fifth transistor 615 are turned on. Also, since the reset signal RIN (output signal OUT12) is at a low potential, The transistor 616 of the clock signal CLK1, CLK2, and 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, and the third transistor Resistor 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 VDD-Vth(611). The potential of the low potential power supply line VSS is reached, the seventh transistor 617 is in a conducting state, and the eighth transistor Since the resistor 618 is non-conductive, the output signals OUT6 to OUT10 are The potential is 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, The second stage shift register unit 601 does not use the clock signal CLK5. Next, 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, the reset signal RIN (output signal The signal OUT7 goes high, turning on the sixth transistor 616 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, the second-stage shift register unit 601 also has the same structure as the first-stage shift register unit. It is driven in the same manner as unit 601.

[0387] That is, 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 the start pulse SP.

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

[0389] In this embodiment, the overlap of the pulses of a clock signal and the next clock signal is called a pulse. Although it is set to 1 / 3 of the width, it is not limited to this, and if it is 1 / 2 or less of the pulse width, how it overlaps Also, the falling edge of a clock signal pulse and the rising edge of the next clock signal pulse may be The falling edge of the clock signal pulse and the rising edge of the next clock signal may be the same. When the rising edges of the pulses are the same, 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 it 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) A semiconductor device according to one embodiment of the present invention includes a sensor ( For example, touch screens using capacitive, resistive, surface elastic, infrared, and optical methods are available. This applies to radiological image detection devices capable of acquiring radiological images for medical purposes. Furthermore, 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, (also called television receivers), computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, 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. 24(A) shows a table 9000 having a display section. A display unit 9003 is built into the housing 9001, and images are displayed on the display unit 9003. It is possible to support the housing 9001 with four legs 9002. The housing 9001 also has 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 other home appliances or allows control of them. 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 tilted relative to the floor by a hinge provided in the housing 9001. It can also be placed vertically and used as a television set. When a large screen television is installed, the free space becomes narrow, but the table If the display unit is built into the device, the space in the room can be used more effectively.

[0396] FIG. 24(B) shows a television device 9100. Television device 9100 The display unit 9103 is incorporated in the housing 9101, and the display unit 9103 displays images. In this example, the housing 9101 is supported by a stand 9105. The figure shows the configuration.

[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 the remote control operation device 9110. The channel and volume can be controlled by the -9109, and the information displayed on the display 9103 In addition, the remote control unit 9110 can be used to 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, It can be 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 9203, and a display section 9204. 203, keyboard 9204, external connection port 9205, pointing device 920 6 and more.

[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] Figures 25(A) and 25(B) show a foldable tablet terminal. ) is in an open state, and the tablet terminal includes a housing 9630, a display unit 9631a, a display part 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 portion 9631a can be used as a touch panel area 9632a. By touching the operation keys 9638, data can be input. In 31a, for example, half of the area has a display function only, and the other half Although the display area 96 has a touch panel function, the display area 96 is not limited to this configuration. The entire area of ​​the display unit 9 may have a touch panel function. The entire surface of 631a is displayed as a keyboard button to serve as a touch panel, and the display part 9631b is displayed. It can be used as a display screen.

[0405] In addition, in the display unit 9631b, as in the display unit 9631a, The area can be used as a touch panel area 9632b. Touch the area where the display switch button 9639 is displayed with your finger or a stylus. This allows keyboard buttons to 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 an external switch that is detected by a light sensor built into the tablet terminal. The display brightness can be optimized according to the amount of light. In addition to sensors, other detection devices such as gyros and acceleration sensors that detect tilt are also available. may be incorporated.

[0408] FIG. 25A shows an example in which the display areas of the display portions 9631b and 9631a are the same. However, there is no particular limitation, and one size may be different from the other size. The display quality may also differ. For example, one display panel may be able to display a higher resolution image than the other. It may also be used as a rule.

[0409] FIG. 25(B) shows the tablet terminal in a closed state, and the tablet terminal includes a housing 9630 and a solar cell 9631. 25B, the charge / discharge control circuit 96 As an example of 34, a configuration having a battery 9635 and a DC-DC converter 9636 is shown. This shows that.

[0410] In addition, since the tablet device can be folded in half, when not in use, the case 9630 is closed. 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 for long-term use.

[0411] In addition, the tablet terminals shown in Figures 25(A) and 25(B) can be used in various Functions that display information (still images, videos, text images, etc.), calendars, dates, or times The function to display the information on the display, and the function to touch input or edit the information displayed on the display. 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 terminal supplies power to the touch panel. The solar cell 9633 can be supplied to a display unit, a video signal processor, or the like. , which can be provided on one or both sides of the housing 9630, and can efficiently charge the battery 9635. 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. 25(B) are shown in FIG. A block diagram is shown in Fig. 25(C) and will be explained. 635, DC-DC converter 9636, converter 9637, switches SW1 to SW3 , the display unit 9631, the battery 9635, the 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 using external light will be described. The power generated by the solar cell is converted into 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 the 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 can be configured to be turned on and charge the battery 9635.

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

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

[0417] In this example, a liquid crystal display device was manufactured using the semiconductor device of Embodiment Mode 1. 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 section does not overlap with the conductive film 304b is used. The liquid crystal display device shown in FIG. 26 includes a driver circuit portion including a conductive film 304b and a conductive film 304c. The conductive film 310c is connected to the light-transmitting conductive film 316a. The conductive film 316a is formed in the opening 3 provided in the insulating film 305, the insulating film 306, and the insulating film 312. 67a, and connects at opening 367b.

[0419] 27A and 27B show layout diagrams of the periphery of the opening. FIG. 27(B) is a layout diagram of the periphery of the opening, and 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. 10 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 conductive film 304b. This allows the layout width to be reduced by 6 μm per opening, enabling the narrowing of the frame of LCD displays. This can be achieved.

[0421] Next, the two openings in the comparative example are changed to one opening as 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 1850 μm. The total area including the protective circuit, signal lines, and sealing area was 2646 μm. there were.

[0423] Furthermore, in the drive circuit section, two openings as in the comparative example are replaced with openings 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 54 μm (6 μm x 9 places). The frame can be reduced by 2.04% (54μm ÷ 2646μm × 100%), This enabled the display device to have a narrower frame. [Example]

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

[0426] As can be seen from FIG. 45(A), the liquid crystal display device of the comparative example had voids in the insulating film. 5(B) is a structure in which the gate electrode is overlapped with the source electrode or the 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 film coverage can be improved. Done. [Example]

[0427] In this example, 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 drive 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. 38(A) A liquid crystal display device was fabricated using the configuration of Figure 26 in a conventional driving circuit that outputs a signal. .

[0429] 43A and 43B show layout diagrams of the drive circuit section. FIG. 43A shows the layout of the drive circuit section of the comparative example. The layout width is 1700 μm. The layout width is 1150 μm. By adopting the state 4 driving circuit, the frame has been reduced by 32.24% (1700μ) compared to the conventional method. m-1150μm) ÷ 1700μm × 100%), and the narrow We were able to frame it.

[0430] Similarly, the channel protection type transistor shown in Modification 6 of Embodiment 1 is added to the driver circuit of Embodiment 4. A liquid crystal display device was fabricated using the transistor. As a comparative example, a liquid crystal display device as shown in FIG. 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 previous one. The layout width is 1700 μm. (B) is a layout diagram of the drive 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 It can be reduced by 7% ((1700μm-1250μm) ÷ 1700μm × 100%) This enabled the frame of the liquid crystal display device to be narrowed. [Example]

[0432] In this example, CA, an In-Ga-Zn oxide that can be used in a liquid crystal display device, The characteristics of the transistor including the 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 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 the 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, a 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 on which a 200 nm thick copper film is laminated. 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 400nm thick aluminum film on 0nm 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 made of a silicon nitride film with a thickness of 100 nm. The film is an indium tin oxide film.

[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 excellent 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 The gate potential was set to 30 V in the dark at 60°C for 1 hour. Figure 47(A) shows the transistor after the +BT test. The vertical axis in the figure represents the variation of the threshold voltage ΔVth [V], and the horizontal axis represents the test time. It is understood from Figure 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. The test was conducted at 60°C for 1 hour (+BT test) and the gate potential was - The test (-BT test) was repeated alternately with a test in which the voltage was 30V and the temperature was 60°C for 1 hour. The results are shown in Figure 47(B). The vertical axis in the figure represents the threshold voltage Vth [V], and the horizontal axis represents the It can be seen from Figure 47(B) 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 Capacitance Line 131_1 Transistor 132 Liquid crystal element 133_1 Capacitor 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 Alignment 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 PCB 344 Light-shielding film 346 Colored film 348 Insulating Film 350 Conductive Film 352 Alignment 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 Capacitor 621 Transistor 622 Transistor 623 Transistor 624 Capacitor 625 Transistor 9000 tables 9001 Case 9002 Legs 9003 Display section 9004 Display button 9005 Power Cord 9033 Fasteners 9034 Switch 9035 Power Switch 9036 Switch 9038 Operation switch 9100 Television equipment 9101 Housing 9103 Display section 9105 Stand 9107 Display section 9109 Operation key 9110 Remote control device 9200 Computer 9201 Main Unit 9202 Housing 9203 Display section 9204 keyboard 9205 External connection port 9206 Pointing Device 9630 chassis 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 the 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 semiconductor film, 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 function as a gate electrode, the first insulating film functions as a gate insulating film, the semiconductor film has a channel formation region, the third conductive film functions 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 with 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 the 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 semiconductor film, 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 function as a gate electrode, the first insulating film functions as a gate insulating film, the semiconductor film has a channel formation region, the third conductive film functions 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 with 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 claim 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.

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