JP2010072219A - Substrate for electro-optical device and electro-optical device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the light-shielding performance of an electro-optical device as well as to increase the aperture ratio, and further, to suppress a channel current in a non-operating period. <P>SOLUTION: The substrate for an electro-optical device is equipped with: a transistor (30) having a semiconductor layer (1a) that includes a first junction region (1c) formed between a source-drain region (1e) close to a pixel electrode and electrically connected to a pixel electrode (9a) and a channel region (1a'), and a second junction region (1b) formed between a source-drain region (1d) close to a data line and electrically connected to a data line (6a) and the channel region, and a gate electrode (31) disposed overlapping the channel region in a plan view on the substrate (10); and a conductive light-shielding film (710) disposed in a layer different from the gate electrode via a first insulating film (41) but formed as at least partially overlapping the first junction region in a plan view on the substrate, and electrically connected to the gate electrode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electro-optical device substrate used in an electro-optical device such as a liquid crystal device, an electro-optical device including the electro-optical device substrate, and a liquid crystal projector including the electro-optical device. The present invention relates to the technical field of electronic equipment.

  A liquid crystal device, which is an example of this type of electro-optical device, includes, for example, an LDD (Thin Film Transistor) between a channel region and a source / drain region of a thin film transistor (TFT) for the purpose of reducing off current. A junction region such as a Lightly Doped Drain region is formed.

  Such a liquid crystal device is often used not only as a direct-view display but also as a light modulation means (that is, a light valve) of, for example, a projection display device. In particular, in the case of a projection display device, since strong light from a light source is incident on a light valve, a light leakage current is generated in the junction area when light is irradiated on the TFT junction area in the light valve. There is a problem that. For such problems, a light shielding film as a light shielding means for shielding incident light is provided on the light valve on the junction region.

  On the other hand, in this type of electro-optical device, for the purpose of improving image quality, the electro-optical device can have high definition and a high aperture ratio. However, by providing the light shielding film for preventing the light leakage current as described above, the opening area is substantially narrowed, and the image quality may be deteriorated.

  As a technique for simultaneously improving the light shielding performance and the aperture ratio of the electro-optical device, for example, a so-called GOLD (Gate Overlapped Lightly Drained Drain) in which a gate electrode is formed so as to overlap with a source / drain region of a TFT. A TFT having a structure has been proposed. Alternatively, an electro-optical device including an upper capacitance electrode as a conductive light-shielding film, which is disposed on the upper layer side of the TFT and includes a first portion that covers the data line side LDD region and a second portion that covers the pixel electrode side LDD region. Substrates have been proposed (see Patent Document 1). Alternatively, a scanning line formed on the upper layer side of the TFT through the interlayer insulating film and having a main line portion at least partially overlapping the low concentration drain region of the TFT and an extension portion overlapping the high concentration drain region of the TFT An electro-optical device substrate is proposed (see Patent Document 2). Alternatively, there has been proposed an electro-optical device substrate in which a longitudinal groove is formed along a semiconductor layer of a TFT and a part of a gate electrode is provided in the formed groove (see Patent Document 3).

JP 2008-26719 A JP 2008-26774 A JP 2008-77030 A

  However, the TFT having the GOLD structure has a technical problem that the drain current may increase during non-operation. In the techniques described in Patent Documents 1 and 3, incident light incident obliquely reaches a semiconductor layer (particularly the pixel electrode side LDD portion) constituting the TFT, and a light leakage current is generated in the TFT. There is a technical problem that there is a possibility. Further, in the technique described in Patent Document 2, a contact hole for connecting the gate electrode and the scanning line must be formed in the pixel, which may hinder high aperture ratio. There is.

  The present invention has been made in view of the above-described problems, for example, and is a substrate for an electro-optical device and an electro-optical device that can improve the light shielding performance, increase the aperture ratio, and further suppress the channel current during non-operation. It is an object to provide an apparatus and an electronic device.

  In order to solve the above problems, an electro-optical device substrate of the present invention includes a substrate, a plurality of data lines and a plurality of scanning lines intersecting with each other on the substrate, the plurality of data lines and the plurality of scanning lines. A pixel electrode formed in each of a plurality of pixels that constitute a display region on the substrate, and a pixel electrode side source / drain region electrically connected to the pixel electrode; A first junction region formed between the channel region, a data line side source / drain region electrically connected to the data line, and a second junction region formed between the channel region. A semiconductor layer and a transistor having a gate electrode arranged so as to overlap the channel region in plan view on the substrate, the gate electrode, and the first insulating film are arranged in different layers. Cage, wherein as viewed in plan on the substrate, wherein with being formed so as to overlap at least partially in a first junction region, and a said gate electrode and electrically connected to the conductive light shielding film.

  According to the substrate for an electro-optical device of the present invention, for example, an image signal is controlled from a data line to a pixel electrode, so that an image display by a so-called active matrix method is possible. The image signal is supplied from the data line to the pixel electrode through the transistor at a predetermined timing when a transistor electrically connected between the data line and the pixel electrode is turned on or off. The pixel electrode is a transparent electrode made of a transparent conductive material such as ITO (Indium Tin Oxide), for example, and is matrixed in an area to be a display area on the substrate corresponding to the intersection of a plurality of data lines and a plurality of scanning lines. A plurality are provided.

  The transistor is provided in a non-opening region that separates open regions of the plurality of pixels from each other. Here, the “opening region” according to the present invention is a region in a pixel through which light is substantially transmitted, for example, a region in which a pixel electrode is formed, and a liquid crystal or the like according to a change in transmittance. This is a region in which the gradation of the emitted light transmitted through the electro-optic material can be changed. In other words, the “open area” means that light condensed on the pixel does not transmit light or is blocked by a light-shielding body such as a wiring, a light-shielding film, and various elements having a light transmittance smaller than that of the transparent electrode. It means the area without. The “non-opening region” according to the present invention means a region where light contributing to display is not transmitted, for example, a region in which light-shielding bodies such as non-transparent wiring, light-shielding film, and various elements are arranged in the pixel. Means.

  The transistor includes a semiconductor layer having a channel region, a pixel electrode side source / drain region and a data line side source / drain region, and a gate electrode. The pixel electrode side source / drain regions are electrically connected to the pixel electrode. The data line side source / drain regions are electrically connected to the data lines.

  A first junction region is formed between the channel region of the semiconductor layer and the pixel electrode side source / drain region. That is, the first junction region is a region formed at the junction between the channel region and the pixel electrode side source / drain region. On the other hand, a second junction region is formed between the channel region and the data line side source / drain region. That is, the second junction region is a region formed at the junction between the channel region and the data line side source / drain region.

  Specifically, for example, the first and second junction regions mean PN junction regions when the transistors are formed as PNP transistors or NPN transistors (that is, N-channel transistors or P-channel transistors). Alternatively, it means an LDD region (that is, an impurity region formed by implanting impurities into a semiconductor layer by ion implantation such as an ion plantation method) when the transistor has an LDD structure.

  For example, the gate electrode is disposed on the upper layer side of the semiconductor layer via the gate insulating film. The gate insulating film is typically laminated on the entire surface of the substrate so as to cover the semiconductor layer.

  For example, the conductive light-shielding film containing titanium nitride (TiN), tungsten silicide (WSi), or the like has a gate electrode and a layer different from each other via the first insulating film (typically, a first layer than the gate electrode). It is arranged on the upper layer side through an insulating film. The conductive light shielding film is formed so as to at least partially overlap the first junction region when viewed in plan on the substrate, and is electrically connected to the gate electrode.

  According to the research of the present inventor, it has been found that the light leakage current is more likely to be generated in the transistor when the light is applied to the first junction region than when the light is applied to the second junction region. Yes. Therefore, as described above, by forming the conductive light shielding film so as to at least partially overlap the first junction region, it is possible to improve the light shielding performance for the first junction region where light leakage current is relatively likely to occur. it can. As a result, the light leakage current flowing through the transistor can be effectively reduced.

  In the present invention, in particular, the conductive light shielding film and the gate electrode are electrically connected to each other. Specifically, for example, the conductive light shielding film and the gate electrode are electrically connected to each other through a contact hole provided in the first insulating film. For this reason, a portion of the conductive light shielding film provided in the contact hole provided in the first insulating film functions as a wall-shaped light shielding body, and is incident obliquely from the second bonding region side. Incident light that reaches one junction region can be shielded.

  In addition, by forming a conductive light-shielding film so as to intensively shield the first junction region where light leakage current is relatively likely to occur, it is possible to prevent the aperture ratio from being lowered more than necessary. That is, a high aperture ratio can be achieved. Furthermore, since the distance in the stacking direction between the portion of the conductive light-shielding film that overlaps the first junction region and the first junction region is relatively large, channel current during non-operation can be suppressed.

  As a result, according to the electro-optical device substrate of the present invention, it is possible to improve the light shielding performance, increase the aperture ratio, and further suppress the channel current during non-operation.

  In one aspect of the substrate for an electro-optical device according to the aspect of the invention, the gate electrode has a protruding portion that protrudes along the semiconductor layer while being spaced apart from the semiconductor layer from a side of a portion overlapping the channel region.

  According to this aspect, the gate electrode is separated from the semiconductor layer from the side of the portion that overlaps the channel region of the semiconductor layer, typically in plan view on the substrate or in three dimensions. It has the protrusion part which protrudes along the semiconductor layer as it is, ie, along the longitudinal direction of a semiconductor layer.

  Here, “sides overlapping the channel region” may mean both sides, that is, a pair of protrusions may protrude on both sides of the semiconductor layer extending in the longitudinal direction. Alternatively, “sides overlapping the channel region” may mean one side. In addition, “side over the channel region” means that there is a distance from the channel region in a direction intersecting with the longitudinal direction of the semiconductor layer, and the protruding portion protrudes with a distance from the semiconductor layer at the base side. Means.

  Furthermore, the protruding portion may protrude from both sides or one side of the semiconductor layer only on the side toward the pixel electrode side source / drain region, or on both sides of the semiconductor layer only on the side toward the data line side source / drain region. You may protrude from one side. Alternatively, the protruding portion may protrude to the side facing the pixel electrode side source / drain region and the data line side source / drain region. That is, up to four protrusions may protrude from the four sides of one semiconductor layer.

  In the present invention, the distance in the direction intersecting with the longitudinal direction of the semiconductor layer between the protrusion and the channel region when viewed in plan on the substrate is caused by the protrusion in at least one of the first and second junction regions. In addition, the generation of the leak current is suppressed, and the incident light that obliquely enters and reaches at least one of the first and second junction regions is blocked.

  According to the research of the present inventor, when the distance between the protrusion and the channel region in the longitudinal direction of the semiconductor layer is shortened in plan view on the substrate, the protrusion having the same potential as the gate electrode is At least one of the first and second junction regions functions as an electrode that applies the same potential as the gate voltage to a greater or lesser extent. That is, an unexpected change in carrier density occurs in at least one of the first and second junction regions. For this reason, in a transistor that is originally supposed to have a channel formed by applying a gate voltage to the channel region, there is a possibility that an operation failure represented by, for example, the occurrence of a leakage current or a change in an on / off threshold value may occur. There is. On the other hand, it has been found that increasing the distance between the protrusion and the channel region reduces the effect of blocking light incident obliquely and reaching at least one of the first and second junction regions.

  However, in the present invention, since the distance between the protrusion and the channel region is set as described above, it is possible to suppress the occurrence of malfunction of the transistor and improve the light shielding performance.

  In this aspect, the gate electrode is disposed on the upper layer side of the semiconductor layer via a gate insulating film, and the projecting portion is a second insulating layer provided on the lower layer side of the gate insulating film and the semiconductor layer. It may include a groove formed in the film or a portion embedded in the through hole.

  If comprised in this way, the light-shielding performance with respect to the incident light which injects diagonally and reaches | attains at least one of the 1st and 2nd junction area | region can be improved more.

  Of the gate electrode, a portion embedded in a groove or a through-hole (for example, a through hole) is a wall-shaped light-shielding along at least one of the first and second junction regions in the semiconductor layer as viewed three-dimensionally. Formed as a body. Therefore, the light shielding performance of light incident obliquely on the semiconductor layer can be enhanced by the groove or the portion embedded in the through-hole as the wall-shaped light shielding element disposed in the vicinity of the semiconductor layer.

  In this aspect, at least a part of the plurality of scanning lines is disposed on a lower layer side of the semiconductor layer via the second insulating film, and the gate electrode is formed on at least a part of the plurality of scanning lines. It may be electrically connected.

  With this configuration, at least 4 of the first junction portion is formed by the gate electrode and the portion of the gate electrode formed in the second insulating film, for example, the portion provided in the through hole, the scanning line, and the conductive light shielding film. Can be covered without gaps, and the light shielding performance can be further improved.

  In another aspect of the electro-optical device substrate of the present invention, the conductive light-shielding film is disposed on an upper layer side of the gate electrode with the first insulating film interposed therebetween, and is formed on the first insulating film. A portion embedded in the groove or the through hole is included.

  According to this aspect, the portion of the conductive light-shielding film embedded in the groove or the through-hole has a wall-like shape along the direction intersecting at least the direction in which the channel region in the semiconductor layer extends, as viewed three-dimensionally. It is formed as a light shield. Accordingly, it is possible to improve the light shielding performance of light incident obliquely on the semiconductor layer.

  Note that a portion of the conductive light shielding film embedded in the groove or the through hole may be further formed along the direction in which the channel region extends. That is, when viewed in plan on the substrate, a portion of the conductive light shielding film embedded in the groove or the through hole may be formed in an “L-shape” or a “U-shape”.

  In another aspect of the electro-optical device substrate of the present invention, the first relay is disposed in the same layer as the conductive light shielding film and is electrically connected to the pixel electrode side source / drain region and the pixel electrode. The electrode further includes a second relay electrode disposed in the same layer as the conductive light shielding film and electrically connected to the data line side source / drain region and the data line.

  According to this aspect, the first relay electrode is disposed in the same layer as the conductive light shielding film, and is electrically connected to the pixel electrode side source / drain region and the pixel electrode. On the other hand, the second relay electrode is disposed in the same layer as the conductive light shielding film, and is electrically connected to the data line side source / drain region and the data line.

  By providing the relay electrode, for example, the electrical resistance between the data line and the data line side source / drain region can be reduced, or disconnection can be prevented, which is very advantageous in practice.

  In another aspect of the electro-optical device substrate of the present invention, the first bonding region and the second bonding region are LDD regions.

  According to this aspect, the transistor has an LDD structure. Therefore, when the transistor is not in operation, the off-current flowing through the pixel electrode side source / drain region and the data line side source / drain region can be reduced, and the electric field relaxation at the drain end during the saturation operation of the transistor can be reduced. It is possible to suppress a decrease in on-state current due to an increase in threshold due to a carrier phenomenon (an issue on reliability related to transistor characteristic deterioration).

  In order to solve the above-described problems, an electro-optical device of the present invention includes the above-described substrate for an electro-optical device of the present invention.

  According to the electro-optical device of the present invention, since the above-described substrate for the electro-optical device of the present invention (including various aspects thereof) is provided, the light shielding performance is improved and the aperture ratio is increased. The channel current at the time can be suppressed.

  In order to solve the above problems, an electronic apparatus of the present invention comprises the above-described electro-optical device of the present invention.

  According to the electronic apparatus of the present invention, since the electro-optical device of the present invention described above is provided, a projection display device, a television set, a mobile phone, an electronic notebook, a portable audio player, which can display a high-quality image, Various electronic devices such as a word processor, a digital camera, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of an electro-optical device substrate, an electro-optical device, and an electronic apparatus according to the present invention will be described with reference to the drawings. In this embodiment, as an example of an electro-optical device, a TFT active matrix driving type liquid crystal device with a built-in driving circuit is used.

  First, the overall configuration of the liquid crystal device according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the TFT array substrate as viewed from the side of the counter substrate together with the components formed thereon, and FIG. 2 is a cross-sectional view taken along the line HH ′ of FIG.

  1 and 2, in the liquid crystal device according to the present embodiment, a TFT array substrate 10 and a counter substrate 20 are arranged to face each other. The TFT array substrate 10 is made of a transparent substrate such as a quartz substrate, a glass substrate, or a silicon substrate, and the counter substrate 20 is made of a transparent substrate such as a quartz substrate or a glass substrate, for example. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 have an image display region 10 a corresponding to the region where the plurality of pixels 100 c are provided. They are bonded to each other by a sealing material 52 provided in a surrounding sealing region.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or an ultraviolet / heat combination type curable resin for bonding the two substrates, and is applied to the TFT array substrate 10 in the manufacturing process, and then irradiated with ultraviolet rays. And cured by heating or the like. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (ie, gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed. Note that the gap material may be arranged in the image display region 10a or a peripheral region located around the image display region 10a in addition to or instead of the material mixed in the seal material 52.

  In FIG. 1, a light-shielding frame light-shielding film 53 that defines the frame area of the image display region 10a is provided on the counter substrate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The sampling circuit 7 is provided so as to be covered with the frame light shielding film 53 on the inner side of the seal region along the one side. The scanning line driving circuit 104 is provided so as to be covered with the frame light-shielding film 53 inside the seal region along two sides adjacent to the one side.

  On the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are arranged in regions facing the four corner portions of the counter substrate 20. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20. Further, a lead wiring 90 for electrically connecting the external circuit connection terminal 102 to the data line driving circuit 101, the scanning line driving circuit 104, the vertical conduction terminal 106, and the like is formed.

  In FIG. 2, on the TFT array substrate 10, a laminated structure in which pixel switching TFTs as drive elements, wiring lines such as scanning lines and data lines are formed is formed. Although the detailed structure of this laminated structure is not shown in FIG. 2, pixel electrodes 9a made of a transparent material such as ITO are formed in an island shape in a predetermined pattern for each pixel on the laminated structure. Has been.

  The pixel electrode 9a is formed in the image display region 10a on the TFT array substrate 10 so as to face a counter electrode 21 described later. On the surface of the TFT array substrate 10 facing the liquid crystal layer 50, that is, on the pixel electrode 9a, an alignment film 16 is formed so as to cover the pixel electrode 9a. The portion from the TFT array substrate 10 to the pixel electrode 9a constitutes one example of the “substrate for electro-optical device” according to the present invention.

  A light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. For example, the light shielding film 23 is formed in a lattice shape when viewed in plan on the facing surface of the facing substrate 20. In the counter substrate 20, a non-opening area is defined by the light shielding film 23, and an area partitioned by the light shielding film 23 is an opening area that transmits light emitted from, for example, a projector lamp or a direct viewing backlight. The light shielding film 23 may be formed in a stripe shape, and the non-opening region may be defined by the light shielding film 23 and various components such as data lines provided on the TFT array substrate 10 side.

  On the light shielding film 23, a counter electrode 21 made of a transparent material such as ITO is formed so as to face the plurality of pixel electrodes 9a. In order to perform color display in the image display region 10a on the light shielding film 23, a color filter (not shown in FIG. 2) may be formed in a region including a part of the opening region and the non-opening region. An alignment film 22 is formed on the counter electrode 21 on the counter surface of the counter substrate 20.

In addition to the data line driving circuit 101, the scanning line driving circuit 104, the sampling circuit 7, etc., a plurality of data lines 6a are provided on the TFT array substrate 10 shown in FIGS.
In addition, a precharge circuit for supplying a precharge signal of a predetermined voltage level in advance of the image signal, an inspection circuit for inspecting the quality, defects, etc. of the liquid crystal device during manufacture or at the time of shipment may be formed. .

  Next, an electrical configuration of the pixel portion of the liquid crystal device according to the present embodiment will be described with reference to FIG. FIG. 3 is an equivalent circuit diagram of various elements, wirings, and the like in a plurality of pixels formed in a matrix forming the image display area of the liquid crystal device according to this embodiment.

  In FIG. 3, a pixel electrode 9 a and a TFT 30 as an example of a “transistor” according to the present invention are formed in each of a plurality of pixels formed in a matrix that forms the image display region 10 a. The TFT 30 is electrically connected to the pixel electrode 9a, and performs switching control of the pixel electrode 9a during operation of the liquid crystal device. The data line 6a to which the image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. Good.

  The scanning line 11 is electrically connected to the gate of the TFT 30, and the liquid crystal device applies scanning signals G1, G2,..., Gm to the scanning line 11 in a pulse-sequential manner in this order at a predetermined timing. It is configured as follows. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,..., Sn supplied from the data line 6a is obtained by closing the TFT 30 as a switching element for a certain period. It is written at a predetermined timing. Image signals S 1, S 2,..., Sn written in a liquid crystal as an example of an electro-optical material via the pixel electrode 9 a are held for a certain period with the counter electrode formed on the counter substrate.

  The liquid crystal constituting the liquid crystal layer 50 (see FIG. 2) modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The transmittance for light is increased, and light having a contrast corresponding to an image signal is emitted from the liquid crystal device as a whole.

  In order to prevent the image signal held here from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode 21 (see FIG. 2). The storage capacitor 70 is a capacitive element that functions as a storage capacitor that temporarily holds the potential of each pixel electrode 9a in response to supply of an image signal. One electrode of the storage capacitor 70 is connected to the drain of the TFT 30 in parallel with the pixel electrode 9a, and the other electrode is connected to the capacitor line 300 with a fixed potential so as to have a constant potential. According to the storage capacitor 70, the potential holding characteristic in the pixel electrode 9a is improved, and display characteristics such as contrast improvement and flicker reduction can be improved. As will be described later, the storage capacitor 70 also functions as a built-in light shielding film that blocks light incident on the TFT 30.

  Next, the shape of the gate electrode of the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 4 is a plan view showing the planar shape of the gate electrode of the liquid crystal device according to this embodiment. 5 is a cross-sectional view taken along the line AA ′ of FIG. 4, and FIG. 6 is a cross-sectional view taken along the line BB ′ of FIG.

  4 to 6, the scale of each layer / member is different for each layer / member so that each layer / member can be recognized on the drawing. In FIGS. 4 to 6, for convenience of explanation, the components on the upper layer side of the conductive light shielding film 710 are not shown.

  In FIG. 4, the scanning line 11 extends along the X direction, and the data line 6 a (not shown here) extends along the Y direction so as to intersect the scanning line 11. A pixel switching TFT 30 is provided at each of the locations where the scanning line 11 and the data line 6a intersect each other.

  The scanning line 11, the data line 6 a, the conductive light shielding film 710, and the TFT 30 are viewed in plan on the TFT array substrate 10, and each pixel has an opening area (that is, each pixel) corresponding to the pixel electrode 9 a (not shown). In FIG. 2, the light is actually disposed in a non-opening region surrounding a region where light that actually contributes to display is transmitted or reflected. That is, the scanning line 11, the data line 6a, the conductive light shielding film 710, and the TFT 30 are arranged in a non-opening region so as not to hinder display.

  4 and 6, the TFT 20 includes the semiconductor layer 1 a and the gate electrode 31.

  The semiconductor layer 1a is made of, for example, polysilicon, and has a channel region 1a ′ having a channel length along the Y direction, a data line side LDD region 1b, a pixel electrode side LDD region 1c, a data line side source / drain region 1d, and a pixel. It consists of an electrode side source / drain region 1e. That is, the TFT 30 has an LDD structure. Here, the “pixel electrode side LDD region 1c” and the “data line side LDD region 1b” according to the present embodiment are examples of the “first junction region” and the “second junction region” according to the present invention, respectively. .

  The data line side source / drain region 1d and the pixel electrode side source / drain region 1e are formed substantially in mirror symmetry along the Y direction with respect to the channel region 1a '. The data line side LDD region 1b is formed between the channel region 1a 'and the data line side source / drain region 1d. The pixel electrode side LDD region 1c is formed between the channel region 1a 'and the pixel electrode side source / drain region 1e. The data line side LDD region 1b, the pixel electrode side LDD region 1c, the data line side source / drain region 1d, and the pixel electrode side source / drain region 1e are formed by implanting impurities into the semiconductor layer 1a by, for example, ion implantation. This is an impurity region.

  The data line side LDD region 1b and the pixel electrode side LDD region 1c are formed as low concentration impurity regions with less impurities than the data line side source / drain region 1d and the pixel electrode side source / drain region 1e, respectively. According to such an impurity region, when the TFT 30 is not operating, it is possible to reduce the off current flowing in the source region and the drain region, and to suppress the decrease in the on current flowing when the TFT 30 is operating. The TFT 30 preferably has an LDD structure. However, the TFT 30 may have an offset structure in which no impurity is implanted into the data line side LDD region 1b and the pixel electrode side LDD region 1c. A self-aligned type in which the data line side source / drain region 1d and the pixel electrode side source / drain region 1e are formed by implanting at a high concentration may be used.

  As shown in FIGS. 5 and 6, the gate electrode 31 is disposed on the upper layer side of the semiconductor layer 1a and is made of, for example, conductive polysilicon. As shown in FIG. 4, the gate electrode 31 has a main body extending in the X direction and a protrusion extending along the Y direction so as to overlap with a region of the channel region 1 a ′ of the TFT 30 where the main body does not overlap. Part 31a. The gate electrode 31 and the semiconductor layer 1a are insulated by an insulating film 2 (see FIGS. 5 and 6) as an example of the “gate insulating film” according to the present invention.

  In FIG. 4, in this embodiment, the gate electrode 31 has an extending portion 31a extending along both sides of the pixel electrode side LDD region 1c as an example of the “projecting portion” according to the present invention. Yes. In other words, the gate electrode 31 has a state of overlapping the channel region 1a ′ and partially surrounding the pixel electrode side LDD region 1c from both sides (ie, so-called inverted U shape). As shown in FIG. 5, a groove 810 is formed in the insulating film 2 and the base insulating film 12. The gate electrode 31 has an in-groove portion 31 b in which a part of the gate electrode 31 is formed in the groove 810.

  Here, the “underlying insulating film 12” according to the present embodiment is an example of the “second insulating film” according to the present invention. In addition to the function of insulating the TFT 30 from the scanning line 11, the base insulating film 12 is formed on the entire surface of the TFT array substrate 10, thereby causing roughness during polishing of the surface of the TFT array substrate 10 and dirt remaining after cleaning. For example, the pixel switching TFT 30 has a function of preventing deterioration of characteristics.

  The groove 810 is dug through the insulating film 2 and the base insulating film 12 until reaching the scanning line 11, and the in-groove portion 31b and the scanning line 11 are electrically connected to each other. In other words, the groove 810 is formed as a contact hole for electrically connecting the gate electrode 31 and the scanning line 11 to each other by the in-groove portion 31b.

  As shown in FIGS. 5 and 6, the scanning line 11 is arranged on the lower layer side of the semiconductor layer 1a via the base insulating film 12, and for example, tungsten (W), titanium (Ti), titanium nitride ( It is made of a light-shielding conductive material such as a refractory metal material such as TiN). The scanning line 11 has a main line portion 11x patterned in a stripe shape along the X direction when viewed in plan on the TFT array substrate 10, and an extension extending from the main line portion 11x along the Y direction. Part 11y.

  As shown in FIGS. 5 and 6, the conductive light-shielding film 710 is higher than the TFT 30 on the TFT array substrate 10 via the interlayer insulating film 41 as an example of the “first insulating film” according to the present invention. And is made of a light-shielding conductive material having a relatively high OD (Optical Density) value such as titanium nitride (TiN) or tungsten silicide (WSi). A groove 820 is formed in the interlayer insulating film 41, and the conductive light shielding film 710 has an in-groove portion 710 a in which a part of the conductive light shielding film 710 is formed in the groove 820.

  The trench 820 is dug through the interlayer insulating film 41 and the insulating film 2 until reaching the gate electrode 31, and the in-groove portion 710a and the gate electrode 31 are electrically connected to each other. In other words, the groove 820 is formed as a contact hole for electrically connecting the conductive light-shielding film 710 and the gate electrode 31 to each other by the in-groove portion 710a.

  Note that the film thickness of the interlayer insulating film 41 is preferably 300 nm (nanometers) to 400 nm. According to the research of the present inventor, when the thickness of the interlayer insulating film 41 is increased (that is, the distance in the stacking direction between the semiconductor layer 1a and the conductive light-shielding film 710 is increased), the pixel electrode side LDD region 1c is increased. Thus, the effect of blocking incident light incident obliquely is reduced. On the other hand, it has been found that when the film thickness of the interlayer insulating film 41 is reduced, the channel current during non-operation increases. However, in the present invention, since the film thickness of the interlayer insulating film 41 is set as described above, the light shielding performance can be improved and the channel current during non-operation can be suppressed.

  As shown in FIG. 4, the conductive light shielding film 710 is disposed so as to at least partially overlap the pixel electrode side LDD region 1 c when viewed in plan on the TFT array substrate 10. Therefore, incident light that enters the pixel electrode side LDD region 1c from the upper layer side can be shielded by the conductive light shielding film 710. Therefore, generation of light leakage current in the pixel electrode side LDD region 1c can be reduced.

  Further, as described above, the gate electrode 31 has an in-groove portion 31 b extending in the groove 810, and the conductive light-shielding film 710 has an in-groove portion 710 a extending in the groove 820. ing. Specifically, as shown in FIG. 5, the groove inner portion 31 b is formed along the inner wall portion of the groove 810 on the semiconductor layer 1 a side, the outer wall portion facing the inner wall portion, and the bottom portion of the groove 810. Has been. The in-groove portion 710 a is formed along the inner wall portion of the groove 820 on the semiconductor layer 1 a side, the outer wall portion facing the inner wall portion, and the bottom portion of the groove 820.

  That is, the in-groove portions 31b and 710a are formed as wall-shaped light shielding bodies along the pixel electrode side LDD region 1c in the semiconductor layer 1a when viewed three-dimensionally. In addition, as shown in FIG. 6, the in-groove portion 710 a is also formed as a wall-shaped light shielding body along the direction in which the scanning line 11 extends (that is, the Y direction in FIG. 4).

  Therefore, incident light incident on the pixel electrode side LDD region 1c obliquely (that is, incident light having a component along the X direction or the Y direction in FIG. 4) can be blocked by the in-groove portions 31b and 710a. . In other words, the in-groove portions 31b and 710a formed as wall-shaped light shields arranged in the vicinity of the pixel electrode side LDD region 1c provide a light shielding performance against incident light incident obliquely on the pixel electrode side LDD region 1c. Can be strengthened. As a result, flicker and pixel unevenness in image display can be reduced.

  The grooves 810 and 820 are provided only on one side of the pixel electrode side LDD region 1c (that is, the left side or the right side in FIG. 5), and the in-groove portions 31b and 710a are formed only on one side of the pixel electrode side LDD region 1c. May be. Also in this case, it is possible to appropriately enhance the light shielding performance with respect to incident light incident obliquely on the pixel electrode side LDD region 1c. However, from the viewpoint of enhancing the light shielding performance, it is desirable to form the in-groove portions 31b and 710a on both sides of the pixel electrode side LDD region 1c as in the present embodiment.

  4, the scanning line 11 includes a channel region 1a ′ of the TFT 30, a data line side LDD region 1b and a pixel electrode side LDD region 1c, a data line side source / drain region 1d, and a pixel electrode side source / drain region. It is formed so as to include a region facing 1e. Therefore, the channel region 1a of the TFT 30 with respect to the return light, such as light reflected from the back surface of the TFT array substrate 10 by the scanning line 11 or light emitted from another liquid crystal device by a multi-plate projector or the like and penetrating the composite optical system. ′ Can be shielded almost or completely. That is, the scanning line 11 can function as a wiring for supplying a scanning signal, and can also function as a light shielding film of the TFT 30 for return light. Therefore, during the operation of the liquid crystal device, the light leakage current in the TFT 30 is reduced, the contrast ratio can be improved, and high-quality image display is possible.

  As shown in FIG. 5, the conductive light shielding film 710, the gate electrode 31, and the scanning line 11 are formed so as to surround the pixel electrode side LDD region 1c. For this reason, the conductive light shielding film 710, the gate electrode 31, and the scanning line 11 can block most of the incident light toward the pixel electrode side LDD region 1c.

  Here, the inventor of the present application concludes that a light leakage current is more likely to occur in the pixel electrode side LDD region 1c than in the data line side LDD region 1b during the operation of the TFT 30. That is, it is concluded that light leakage current in the TFT 30 is more likely to occur when the pixel electrode side LDD region 1c is irradiated with light than when the data line side LDD region 1b is irradiated during operation of the TFT 30. ing. Therefore, as described above, by forming the gate electrode 31 and the conductive light shielding film 710, the light shielding performance for the pixel electrode side LDD region 1c where the light leakage current is relatively likely to be generated can be improved, and the light leakage flowing through the TFT 30 can be improved. Current can be effectively reduced.

  In addition, the necessary minimum light shielding is applied to the data line side LDD region 1b in which light leakage current is less likely to occur as compared with the pixel electrode side LDD region 1c, thereby preventing an unnecessary reduction in the aperture ratio. be able to. Here, the “aperture ratio” means the ratio of the opening area in the pixel size including the opening area and the non-opening area. The larger the aperture ratio, the better the display performance of the liquid crystal device.

  As shown in FIG. 6, in the same layer as the conductive light shielding film 710, the data line side source / drain region 1d, the relay electrode 720 electrically connected via the contact hole 81, and the pixel electrode side A source / drain region 1 e and a relay electrode 730 that is electrically connected via a contact hole 83 are formed. Here, the “relay electrode 720” and the “relay electrode 730” according to the present embodiment are examples of the “second relay electrode” and the “first relay electrode” according to the present invention, respectively.

  By providing such relay electrodes 720 and 730, the electrical resistance between the semiconductor layer 1a and the data line 6a, the pixel electrode 9a, etc. disposed on the upper layer side of the relay electrodes 720 and 730 is reduced. Or disconnection can be prevented.

(Modification)
Next, a modification of the liquid crystal device according to the present embodiment will be described with reference to FIG. FIG. 7 is a plan view showing the planar shape of the gate electrode of the liquid crystal device according to the modification of the present embodiment having the same meaning as FIG.

  As shown in FIG. 7, in the present modification, scanning lines 11a and 11b extending along the X direction are provided. The gate electrode 31 is formed as a part of the scanning line 11a. The scanning line 11a is disposed on the upper layer side of the semiconductor layer 1a via the insulating film 2 (see FIG. 5). On the other hand, the scanning line 11b is disposed on the lower layer side of the semiconductor layer 1a via the base insulating film 12 (see FIG. 5).

<Electronic equipment>
Next, a case where the above-described liquid crystal device is applied to a projector which is an example of an electronic device will be described with reference to FIG. The liquid crystal device described above is used as a light valve of a projector. FIG. 8 is a plan view showing a configuration example of the projector.

  As shown in FIG. 8, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G have the same configuration as that of the above-described liquid crystal device, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit, respectively. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display images by the liquid crystal panels 1110R and 1110B need to be horizontally reversed with respect to the display images by the liquid crystal panel 1110G.

  Since light corresponding to the primary colors R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition to the electronic device described with reference to FIG. 8, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook , Calculators, word processors, workstations, videophones, POS terminals, devices with touch panels, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. For electro-optical devices with such changes A substrate, an electro-optical device, and an electronic apparatus are also included in the technical scope of the present invention.

It is a top view which shows the whole structure of the liquid crystal device which concerns on embodiment of this invention. It is the HH 'sectional view taken on the line of FIG. FIG. 4 is an equivalent circuit diagram of a plurality of pixel units of the liquid crystal device according to the embodiment of the present invention. It is a top view which shows the planar shape of the gate electrode of the liquid crystal device which concerns on this embodiment. FIG. 5 is a cross-sectional view taken along line AA ′ in FIG. 4. FIG. 5 is a sectional view taken along line BB ′ in FIG. 4. It is a top view which shows the planar shape of the gate electrode of the liquid crystal device which concerns on the modification of this embodiment. It is a top view which shows the structure of the projector which is an example of the electronic device to which the electro-optical apparatus is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a ... Semiconductor layer, 1a '... Channel region, 1b ... Data line side LDD region, 1c ... Pixel electrode side LDD region, 1d ... Data line side source / drain region, 1e ... Pixel electrode side source / drain region, 2 ... Insulation Film 11, 11 a, 11 b Scan line 6 a Data line 9 a Pixel electrode 10 TFT array substrate 10 a Image display area 12 Base insulating film 20 Counter substrate 21 Counter electrode 23 DESCRIPTION OF SYMBOLS ... Light shielding film, 31 ... Gate electrode, 31b, 710a ... In-groove part, 41 ... Interlayer insulating film, 50 ... Liquid crystal layer, 52 ... Sealing material, 53 ... Frame light shielding film, 70 ... Storage capacity, 101 ... Data line drive circuit , 102 ... External circuit connection terminals, 104 ... Scanning line drive circuit, 300 ... Capacitance line, 710 ... Conductive light shielding film, 810, 820 ... Groove

Claims (9)

A substrate,
A plurality of data lines and a plurality of scanning lines intersecting each other on the substrate;
A pixel electrode defined in correspondence with the intersection of the plurality of data lines and the plurality of scanning lines and formed on each of a plurality of pixels constituting a display region on the substrate;
A first junction region formed between a pixel electrode side source / drain region electrically connected to the pixel electrode and a channel region; and a data line side source / drain region electrically connected to the data line. And a semiconductor layer having a second junction region formed between the channel region and a transistor having a gate electrode disposed so as to overlap the channel region in plan view on the substrate;
The gate electrode and the first insulating film are disposed in different layers, and are formed so as to at least partially overlap the first junction region when viewed in plan on the substrate, An electro-optical device substrate comprising: a conductive light-shielding film electrically connected to the gate electrode.   2. The electro-optical device according to claim 1, wherein the gate electrode has a protruding portion that protrudes along the semiconductor layer while being spaced apart from the semiconductor layer from a side of a portion overlapping the channel region. Substrate. The gate electrode is disposed on the upper layer side of the semiconductor layer via a gate insulating film,
The said protrusion part contains the part embedded in the groove | channel or through-hole formed in the 2nd insulating film provided in the lower layer side of the said gate insulating film and the said semiconductor layer. Electro-optical device substrate. At least some of the plurality of scanning lines are disposed on a lower layer side of the semiconductor layer via the second insulating film,
The electro-optical device substrate according to claim 3, wherein the gate electrode is electrically connected to at least a part of the plurality of scanning lines.   The conductive light-shielding film is disposed on an upper layer side of the gate electrode with the first insulating film interposed therebetween, and includes a portion embedded in a groove or a through-hole formed in the first insulating film. The substrate for an electro-optical device according to claim 1, wherein the substrate is an electro-optical device. A first relay electrode that is disposed in the same layer as the conductive light shielding film and is electrically connected to the pixel electrode side source / drain regions and the pixel electrode;
The second relay electrode disposed in the same layer as the conductive light shielding film and electrically connected to the data line side source / drain region and the data line. The substrate for an electro-optical device according to claim 5.   The electro-optical device substrate according to claim 1, wherein the first bonding region and the second bonding region are LDD regions.   An electro-optical device comprising the electro-optical device substrate according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 8.

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