JP2009047967A - Electro-optical device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce production of a light leakage current in a TFT within a pixel in an electro-optical device of a liquid crystal device etc. <P>SOLUTION: The electro-optical device includes a substrate (10), a data line (6a) arranged on the substrate, a scanning line (11) arranged on an upper layer side of the data line and intersects with the data line, a pixel electrode (9a) arranged on the upper layer side of the scanning line and is arranged in correspondence to the intersection of the data line and the scanning line, a capacitive electrode (71) arranged so as to face the pixel electrode via a capacitive dielectric film (75) in a lower layer side of the pixel electrode, and a semiconductor layer (1a) arranged on the upper layer side of the data line and on the lower layer side of the scanning line, and has a data line side source drain region (1d) and a pixel electrode side source drain region (1e), and a channel region disposed to face a gate electrode (3a) composed of a part of the scanning line or connected to the scanning line via a dielectric film (41). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  A liquid crystal device, which is an example of this type of electro-optical device, includes, for example, a thin film transistor (TFT) and the like, and in addition to this, various wirings and electrodes such as thin data lines and scanning lines are laminated. Has been configured.

  By adopting the laminated structure as described above, the liquid crystal device can display a high-definition image while being small. For example, Patent Document 1 discloses a technique for realizing a liquid crystal device with a laminated structure including eight conductive layers.

JP 2001-281684 A

  However, in the liquid crystal device having the laminated structure as described above, the configuration of the device becomes complicated due to an increase in the number of layers, leading to an increase in the complexity of the manufacturing process, an increase in the manufacturing period, and an increase in cost. There is a technical problem.

  The present invention has been made in view of, for example, the above-described problems. For example, the present invention is an electro-optical device such as a liquid crystal device driven by an active matrix method, which is configured with relatively few layers and has high definition. It is an object of the present invention to provide an electro-optical device that enables display and an electronic apparatus including the electro-optical device.

  In order to solve the above problems, the electro-optical device of the present invention is provided with a substrate, a data line provided on the substrate, a scanning line provided on an upper layer side of the data line, and intersecting the data line, A pixel electrode provided on an upper layer side of the scanning line, provided for each pixel defined corresponding to an intersection of the data line and the scanning line, and on a lower layer side of the pixel electrode; A capacitor electrode provided so as to be opposed to each other with a capacitor insulating film, and a data line side source provided on the upper layer side of the data line and on the lower layer side of the scanning line and electrically connected to the data line A drain region, a pixel electrode side source / drain region electrically connected to the pixel electrode, and a gate electrode formed of a part of the scanning line or electrically connected to the scanning line through a gate insulating film Cha arranged to And a semiconductor layer having a Le region.

  According to the electro-optical device of the invention, the data line is provided on the substrate so as to extend, and the scanning line is provided on the upper layer side of the data line so as to extend across the data line. It has been. That is, the data line and the scanning line are provided so as to cross each other.

  A pixel electrode is provided on the upper layer side of the scanning line. The pixel electrode is a transparent electrode made of a transparent conductive material such as ITO (Indium Tin Oxide), for example, and a plurality of pixel electrodes are provided in a matrix form in a region to be a display region on the substrate corresponding to the intersection of the data line and the scanning line. It is done. Further, a capacitor electrode is provided on the lower layer side of the pixel electrode so as to face the pixel electrode through a capacitor insulating film. The capacitor electrode may be connected to the capacitor line, or a part of the capacitor line may be the capacitor electrode. The capacitor electrode is connected to a power supply or wiring having a predetermined potential via a capacitor line.

  In addition, a semiconductor layer is provided on the upper layer side of the data line and on the lower layer side of the scanning line, the data line side source / drain region electrically connected to the data line, and the pixel electrode electrically connected to the pixel electrode A side source / drain region and a channel region disposed so as to face a gate electrode formed of a part of the scanning line or connected to the scanning line through a gate insulating film. In addition to the semiconductor layer, a thin film transistor is constructed on the lower layer side of the capacitor electrode on the substrate from the gate electrode and the gate insulating film. Here, the semiconductor layer may further have an LDD region, and may be constructed as an LDD type thin film transistor. Alternatively, a double-gate thin film transistor in which two gate electrodes are sandwiched from above and below or two gate electrodes exist in two channel regions connected in series may be constructed. Furthermore, there may be three or more gate electrodes.

  In the present invention, as described above, the electro-optical device is configured by the five conductive layers (that is, the data line, the semiconductor layer, the scanning line, the capacitor electrode, and the pixel electrode in order from the lower layer side). Note that an insulating film such as the above-described capacitive insulating film or gate insulating film is provided between the conductive layers. In addition to the conductive layer and the insulating film described above, other wirings, electrodes, or the like may be provided.

  With the configuration as described above, the electro-optical device according to the present invention can control the supply of an image signal from, for example, a data line to a pixel electrode during its operation, and can display an image by a so-called active matrix method. The image signal is transmitted from the data line at a predetermined timing by turning on and off a thin film transistor made of a semiconductor layer electrically connected between the data line and the pixel electrode in accordance with the scanning signal supplied from the scanning line. It is supplied to the pixel electrode through the thin film transistor. That is, the thin film transistor performs switching control of the pixel electrode. Further, by providing the capacitor electrode, the voltage applied to the pixel electrode is prevented from being attenuated, and a high contrast display or the like is realized.

  As described above, according to the electro-optical device according to the present invention, a high-definition image can be displayed by a limited number of conductive layers. Therefore, it is possible to prevent an increase in the complexity of the manufacturing process such as formation of deep contact holes, an increase in manufacturing period, an increase in cost, and the like due to an increase in the conductive layer.

  In one aspect of the electro-optical device of the present invention, the data line functions as a light-shielding film that shields light incident from the substrate side.

  According to this aspect, light incident from the substrate side is blocked by the data line provided on the substrate. Note that as the light-shielding film, a high melting point metal such as titanium or tungsten that can withstand high-temperature treatment of the semiconductor layer and has excellent conductivity is preferably used. Alternatively, in the case where low temperature treatment is sufficient for the semiconductor layer, not only the refractory metal but also aluminum or the like excellent in conductivity may be used.

  If the light incident from the substrate side is not shielded, the incident light may cause a light leakage current in the semiconductor layer, which may cause display defects.

  However, in the present invention, in particular, since the data line functions as a light shielding film, it is possible to suppress the occurrence of the above-described light leakage current without providing a separate light shielding film. That is, light shielding can be realized without complicating the apparatus configuration. Therefore, it is possible to prevent an increase in manufacturing period and cost.

  In another aspect of the electro-optical device according to the aspect of the invention, the back surface light-shielding film is further provided in the same layer as the data line so as to cover the channel region when viewed in plan on the substrate.

  According to this aspect, the channel region in the semiconductor layer is covered with the back surface light-shielding film as viewed in plan on the substrate. Here, the “back surface” means the lower surface of the semiconductor layer on the substrate, that is, the back surface, and the “back surface light shielding film” means a film that shields the back surface from the back surface side. In other words, the back surface light shielding film is a film in which the stacking position on the substrate is on the lower layer side than the semiconductor layer. Further, the back light shielding film is provided in the same layer as the data line. Here, the “same layer” means a layer formed by the same film forming process, and the thickness of the layer, the position where the layer is arranged, and the like may be different from each other. Further, the data line and the back light shielding film may not be connected to each other (that is, the back light shielding film may have an island shape). Alternatively, the back light shielding film may further provide a function as a redundant wiring of the scanning line. That is, the back surface light shielding film may be provided so as to extend at least partially along the scanning line.

  By further providing the back surface light shielding film, it is possible to more reliably shield light incident on the channel region from the substrate side. The channel region is theoretically likely to generate a light leakage current. In particular, when a strong light source light is incident from the front side of the substrate as in projector applications, the reflected light from the back side of the substrate becomes strong, or after passing through another light valve in a multi-plate projector, penetrates the composite optical system. For example, when the light incident from the back side of the substrate is strong, the light shielding by the back reflecting film is extremely effective. Therefore, by blocking light incident on the channel region, generation of light leakage current can be more effectively suppressed.

  Furthermore, the back surface light-shielding film is formed by the same film forming process as the gate line. Therefore, it is possible to realize light shielding as described above without increasing the number of conductive layers constituting the device. Accordingly, it is possible to prevent the layered structure on the substrate and the complicated sophistication of the manufacturing process, the lengthening of the manufacturing period, the increase in cost, and the like.

  In the aspect further including the back surface light-shielding film described above, the back surface light-shielding film is provided at least partially facing the channel region via another gate insulating film provided on the lower layer side of the semiconductor layer. The gate electrode may function as another gate electrode that sandwiches the channel region from above and below.

  If comprised in this way, a back surface light shielding film functions as another gate electrode which clamps a channel area | region from the upper and lower sides with a gate electrode. In other words, the transistor in this embodiment has two gate electrodes (a so-called double gate structure). The back surface light-shielding film is provided at least partially opposite to the channel region via another gate insulating film provided on the lower layer side of the semiconductor layer.

  According to the above-described configuration, the channel can be formed on both the upper side (that is, the scanning line side) and the lower side (that is, the back surface light shielding film side) of the channel region. As a result, the current flowing through the channel region when the transistor is turned on (that is, the on-state current) can be increased as compared with the case where the channel is formed only on the upper side of the channel region of the semiconductor layer. Therefore, it is possible to display a high quality image.

  Alternatively, in an aspect further including a back surface light-shielding film, the back surface light-shielding film may be configured to function at least partially as the gate electrode facing the channel region from the lower layer side through the gate insulating film. .

  If comprised in this way, the back surface light shielding film is at least partially opposed to the channel region from the lower layer side through the insulating film, and functions as a gate electrode. The back surface light-shielding film is connected to, for example, a scanning line through a contact hole or the like, and can be turned on and off by applying a gate voltage.

  As described above, if the back light-shielding film functions as a gate electrode, the scanning line does not need to function as a gate electrode. Therefore, for example, only the gate electrode made of the back surface light shielding film may be provided as the gate electrode. That is, a transistor configuration in which the gate electrode exists only on the lower layer side of the channel region may be used. Therefore, the degree of freedom in configuring the transistor is increased, which is extremely advantageous in design.

  In the aspect in which the back surface light shielding film described above functions as a gate electrode, the gate electrode may be connected to the scanning line through a contact hole provided on the side of the semiconductor layer.

  According to this structure, the contact hole is provided on the side of the semiconductor layer, and the gate electrode is connected to the scanning line through the contact hole. That is, the scanning line and the back light shielding film are electrically connected to each other. Thereby, the back surface light-shielding film reliably functions as a gate electrode. Therefore, it is possible to reliably obtain the effect of increasing the degree of freedom in configuring the above-described transistor.

  In another aspect of the electro-optical device according to the aspect of the invention, the scanning line includes the gate electrode that locally approaches the channel region as the part, and a portion adjacent to the gate electrode is formed by the gate insulating film. Also, it is laminated on the semiconductor layer through a thick interlayer insulating film.

  According to this aspect, the gate electrode provided as a part of the scanning line is disposed so as to locally approach the channel region. The portion adjacent to the gate electrode is stacked on the semiconductor layer through an interlayer insulating film that is thicker than the gate insulating film. That is, the portion adjacent to the gate electrode is arranged away from the semiconductor layer as compared to the gate electrode.

  If the distance between the portion adjacent to the gate electrode and the semiconductor layer is the same as the distance between the gate electrode and the semiconductor layer, the application of the electric field from this adjacent portion is equivalent to the application of the electric field from the gate electrode. As a result, the gate electrode does not function normally.

  However, in this embodiment, in particular, as described above, the portion adjacent to the gate electrode is stacked on the semiconductor layer via the interlayer insulating film that is thicker than the gate insulating film. Therefore, the portion adjacent to the gate electrode is arranged to be separated by the difference in thickness between the gate insulating film and the interlayer insulating film. Therefore, the gate electrode functions normally and can function reliably as a part of the transistor.

  In another aspect of the electro-optical device according to the aspect of the invention, the capacitor electrode functions as a shield layer that prevents coupling between the pixel electrode and a lower layer side of the capacitor electrode.

  According to this aspect, since the capacitor electrode is provided on the lower layer side than the pixel electrode, the coupling between the pixel electrode and the lower layer side of the capacitor electrode (that is, the electrical or electromagnetic coupling such as the capacitive coupling) is performed. It functions as a shield layer for preventing (ring), that is, a conductive layer for electromagnetic shielding. The “lower layer side of the capacitor electrode” is, for example, the above-described data line, scanning line, semiconductor layer, and the like. Moreover, when another conductive layer exists, those layers may be sufficient.

  By preventing the coupling, it is possible to reduce the possibility of potential fluctuation or the like in the pixel electrode. Therefore, it is possible to display a higher quality image.

  In another aspect of the electro-optical device according to the aspect of the invention, the electro-optical device further includes a counter substrate that is disposed to face the pixel electrode side of the substrate and sandwiches an electro-optical material between the substrate and the substrate. Features.

  According to this aspect, the counter substrate is disposed on the side of the substrate where the pixel electrode is formed, and the electro-optical material is sandwiched between the substrate and the counter substrate. The electro-optic material can be controlled by applying a voltage from the pixel electrode. Therefore, for example, by applying a vertical electric field or a horizontal electric field between the pair of substrates, it is possible to display an image by allowing light to enter while controlling the electro-optical material.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

  According to the electronic apparatus of the present invention, since the above-described electro-optical device according to the present invention is provided, it is possible to perform high-quality display while preventing an increase in the manufacturing period and an increase in cost. Various electronic devices such as a projection display device, a television, a cellular phone, an electronic notebook, a word processor, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a video phone, a POS terminal, and a touch panel can be realized. Further, as the electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper 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 the present invention will be described with reference to the drawings. In the following embodiments, a driving circuit built-in type TFT active matrix driving type liquid crystal device, which is an example of the electro-optical device of the present invention, is taken as an example.

<First Embodiment>
A liquid crystal device according to a first embodiment of the present invention will be described with reference to FIGS.

  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 schematic plan view showing a configuration of a liquid crystal device as viewed from the counter substrate side together with each component formed on the TFT array substrate, and FIG. 2 is a schematic diagram of HH ′ of FIG. It is sectional drawing.

  1 and 2, the liquid crystal device is composed of a TFT array substrate 10 and a counter substrate 20 which are arranged to face each other. The TFT array substrate 10 is a transparent substrate such as a quartz substrate, a glass substrate, or a silicon substrate. The counter substrate 20 is also a transparent substrate made of the same material as the TFT array substrate 10, 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 are provided in a seal material provided in a seal region around the image display region 10a. 52 are bonded to each other.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. Further, for example, in the sealing material 52, a gap material 56 such as a glass fiber or a glass bead for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed. The liquid crystal device according to this embodiment is small and suitable for performing enlarged display for a light valve of a projector.

  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 seal 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.

  On the TFT array substrate 10, a data line driving circuit 101, a sampling circuit 7, a scanning line driving circuit 104, and an external circuit connection terminal 102 are formed in the peripheral area located around the image display area 10 a.

  In the peripheral region on the TFT array substrate 10, the data line driving circuit 101 and the external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 on the outer peripheral side from the seal region. Further, a region located on the inner side of the seal region in the peripheral region on the TFT array substrate 10 is covered with the frame light shielding film 53 along one side of the image display region 10 a along one side of the TFT array substrate 10. Thus, the sampling circuit 7 is arranged.

  The scanning line driving circuit 104 is provided along two sides adjacent to one side of the TFT array substrate 10 so as to be covered with the frame light shielding film 53. Further, in order to electrically connect the two scanning line driving circuits 104 provided on both sides of the image display region 10a in this way, the TFT array substrate 10 is covered with the frame light shielding film 53 along the remaining side. A plurality of wirings 105 are provided.

  In the peripheral region on the TFT array substrate 10, vertical conduction terminals 106 are disposed in regions facing the four corners of the counter substrate 20, and vertical conduction is provided between the TFT array substrate 10 and the counter substrate 20. A material is provided corresponding to the vertical conduction terminal 106 and electrically connected to the terminal 106.

  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. In the image display area 10a, pixel electrodes 9a are provided in a matrix on the upper layer of wiring such as pixel switching TFTs, scanning lines, and data lines. An alignment film 16 is formed on the pixel electrode 9a. In the present embodiment, the pixel switching element may be composed of various transistors in addition to the TFT.

  On the other hand, a light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. The light shielding film 23 is formed of, for example, a light shielding metal film or the like, and is patterned, for example, in a lattice shape in the image display region 10a on the counter substrate 20. A counter electrode 21 made of a transparent material such as ITO is formed on the light shielding film 23 (below the light shielding film 23 in FIG. 2) so as to face the plurality of pixel electrodes 9a. An alignment film 22 is formed on the upper side (below the counter electrode 21 in FIG. 2).

  The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films. A liquid crystal storage capacitor is formed between the pixel electrode 9 a and the counter electrode 21 by applying a voltage to each of the liquid crystal devices during driving.

  Although not shown here, on the TFT array substrate 10, in addition to the data line driving circuit 101 and the scanning line driving circuit 104, a plurality of data lines are precharged at a predetermined voltage level prior to the image signal. A precharge circuit to be supplied, 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, each of a plurality of pixels formed in a matrix forming the image display region 10 a has a TFT 30 constructed including the pixel electrode 9 a and the “semiconductor layer” and “gate electrode” according to the present invention. Is formed. 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 according to this embodiment applies the scanning signals G1, G2,..., Gm to the scanning line 11 in this order at a predetermined timing. It is configured to apply line-sequentially. 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 electrically in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode 21 (see FIG. 2). ing. 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. 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. A specific configuration of the storage capacitor 70 will be described in detail later.

  Next, a specific configuration of the pixel portion in the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 4 is a plan view of the pixel portion of the liquid crystal device according to the first embodiment. FIG. 5 is a cross-sectional view taken along the line A-A ′ of FIG. 4. In FIGS. 4 and 5, the scale of each layer / member is different for each layer / member to have a size that can be recognized on the drawing. 4 and 5, for convenience of explanation, illustration of a portion located above the pixel electrode 9a is omitted. In FIG. 4, some wirings and electrodes such as the scanning lines 11 are transparently illustrated.

  In FIG. 4, a plurality of pixel electrodes 9a are provided in a matrix on the TFT array substrate 10 (see FIG. 2), and are transparent electrodes made of a transparent conductive material such as ITO, for example. Data lines 6a and scanning lines 11 are provided along the vertical and horizontal boundaries of the pixel electrode 9a. In other words, the scanning line 11 extends along the X direction, and the data line 6 a extends along the Y direction so as to intersect the scanning line 11. On the lower layer side of the scanning line 11, a pixel switching TFT 30 is provided for each pixel electrode 9a.

  The scanning line 11, the data line 6 a, and the TFT 30 transmit light that actually contributes to display in each pixel corresponding to the pixel electrode 9 a when viewed in plan on the TFT array substrate 10 (that is, in each pixel). Or a non-opening region surrounding the region to be reflected). That is, the scanning lines 11, the data lines 6a, and the TFTs 30 are arranged not in the opening area of each pixel but in the non-opening area so as not to hinder display.

  During the operation of the liquid crystal device according to the present embodiment, the supply of the image signal from the data line 6a to the pixel electrode 9a is controlled, and the so-called active matrix image display is possible. The image signal is data at a predetermined timing when the TFT 30 which is a switching element electrically connected between the data line 6a and the pixel electrode 9a is turned on / off according to the scanning signal supplied from the scanning line 11. The pixel electrode 9a is supplied from the line 6a through the TFT 30.

  4 and 5, the TFT 30 includes the semiconductor layer 1 a and the gate electrode 3 a formed as a part of the scanning line 11.

  The semiconductor layer 1a is made of, for example, polysilicon, and includes a channel region 1a ′, 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 electrode side source provided along the X direction. It consists of a drain region 1e. That is, the TFT 30 has an LDD structure. The data line side source / drain region 1 d is electrically connected to the data line 6 a through a contact hole 81. The pixel electrode side source / drain region 1 e is electrically connected to the pixel electrode 9 a through a contact hole 83.

  Thus, since the contact hole 81 penetrates only one layer of the interlayer insulating film (that is, the base insulating film 12), the depth thereof can be relatively light, and the opening can be easily performed by etching or the like. is there. Also, since the aspect ratio of the hole is small, it is easy to make a good contact even at the bottom. Similarly, since the contact hole 83 penetrates only the two-layer interlayer insulating film (that is, the first interlayer insulating film 41 and the second interlayer insulating film 42), the opening is easy and the bottom is also good. Easy to contact.

  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 X 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, the off-current flowing between the source region and the drain region can be reduced, and a decrease in the on-current flowing when the TFT 30 is operating can be suppressed. The TFT 30 preferably has an LDD structure. However, the TFT 30 may have an offset structure in which no impurity implantation is performed in the data line side LDD region 1b and the pixel electrode side LDD region 1c. A self-alignment type in which the data line side source / drain region and the pixel electrode side source / drain region are formed by implanting the concentration may be used.

  In FIG. 5, the gate electrode 3a is formed as a part of the scanning line 11, and is formed of, for example, conductive polysilicon. The scanning line 11 is formed so as to extend along the X direction. A portion of the scanning line 11 that overlaps the channel region 1a 'functions as the gate electrode 3a. As shown in the drawing, the gate electrode 3a is provided so as to be locally close to the channel region 1a '. Further, the gate electrode 3 a and the channel region 1 a ′ are insulated by the first interlayer insulating film 41.

  4 and 5, a back light shielding film 6b is provided in the same layer as the data line 6a (that is, lower layer side than the TFT 30 on the TFT array substrate 10 via the base insulating film 12). The back light shielding film 6b is formed by the same film forming process as the data line 6a. For example, Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), Pd (palladium). It is made of a light-shielding material such as a simple metal, an alloy, a metal silicide, a polysilicide, or a laminate of these containing at least one of refractory metals such as.

  The back surface light-shielding film 6b shields light incident from the TFT array substrate 10 side (that is, arrows P2 and P3 in the figure) and prevents light from entering the channel region 1a ′ of the TFT 30 and its periphery. To prevent. Further, light that cannot be covered by the back surface light shielding film 6b (that is, the arrow P1 in the figure) is shielded by the data line 6a. In addition, as long as the position, shape, etc. of the back surface light-shielding film 6b are formed by the same film forming process as that of the data line 6a, various modes can be taken. Further, if the light shielding can be performed by the data line 6a, the back surface light shielding film 6b may not be provided.

  As described above, by providing the back surface light-shielding film 6b, it is possible to prevent light leakage current from occurring in the channel region 1a '. Therefore, the contrast ratio can be improved and high-quality image display can be performed. In this embodiment, as described above, the back light shielding film 6b is provided in the same layer as the data line 6a, thereby preventing the apparatus from becoming complicated.

  In FIG. 5, the base insulating film 12 is formed on the entire surface of the TFT array substrate 10 in addition to the function of interlayer insulating the TFT 30 from the back surface light-shielding film 6b. It has a function of preventing deterioration of the characteristics of the pixel switching TFT 30 due to dirt remaining after cleaning.

  In FIG. 5, a capacitive electrode 71 is provided on the upper layer side of the scanning line 11 on the TFT array substrate 10 via the second interlayer insulating film 42. The capacitor electrode 71 is provided so as to cover both the opening region and the non-opening region except for the portion where the contact hole 83 connecting the pixel electrode 9a and the pixel electrode side source / drain region 1e is provided. The capacitor electrode 71 is disposed so as to face the pixel electrode 9 a with the capacitor insulating film 75 therebetween, and forms a storage capacitor 70.

  The capacitive electrode 71 is a fixed potential side capacitive electrode that is electrically connected to a constant potential source through a capacitive line, for example, and maintained at a fixed potential. The capacitor electrode 71 is formed of a non-transparent metal film containing a metal or alloy such as Al (aluminum) or Ag (silver), for example, and also functions as an upper light shielding film (built-in light shielding film) that shields the TFT 30. . The capacitor electrode 71 includes, for example, a single metal, an alloy, a metal silicide, a polysilicide, or a laminate of these including at least one of refractory metals such as Ti, Cr, W, Ta, Mo, and Pd. You may be comprised from. By comprising in this way, the function as a built-in light shielding film can be improved.

  The capacitor insulating film 75 is, for example, a single layer structure or a multilayer structure formed of a silicon oxide (SiO 2) film such as an HTO (High Temperature Oxide) film, an LTO (Low Temperature Oxide) film, or a silicon nitride (SiN) film. have.

  As described above, by forming the storage capacitor 70, the potential holding characteristic of the pixel electrode 9a is improved, and it is possible to improve display characteristics such as improvement of contrast and reduction of flicker. In this embodiment, in particular, since the storage capacitor 70 is formed by the pixel electrode 9a and the capacitor electrode 71, for example, compared with the case where the storage capacitor is formed by providing an upper electrode and a lower electrode in addition to the pixel electrode 9a. Thus, the device configuration can be simplified.

  The configuration of the pixel portion described above is common to each pixel portion as shown in FIG. Such pixel portions are periodically formed in the image display area 10a (see FIG. 1).

  With the configuration as described above, the liquid crystal device according to the present embodiment can display a high-quality image during its operation. Further, since it can be constituted by a relatively small number of conductive layers, it is possible to prevent the laminated structure of various wirings and electrodes from becoming complicated. Therefore, it is possible to prevent an increase in manufacturing period and cost.

Second Embodiment
Next, a liquid crystal device according to a second embodiment will be described with reference to FIGS. FIG. 6 is a plan view of the pixel portion of the liquid crystal device according to the second embodiment, and FIG. 7 is a sectional view taken along line BB ′ of FIG. FIG. 8 is a sectional view showing a modification of the liquid crystal device according to the second embodiment. The second embodiment is different from the first embodiment described above in that the back surface light-shielding film 6b functions as a gate electrode, and the other configurations are substantially the same. Therefore, in the second embodiment, the configuration of the back surface light shielding film 6b will be described in detail, and description of other configurations will be omitted as appropriate. 6 to 8, the same reference numerals are assigned to the same components as those of the first embodiment.

  In FIG. 6, in the liquid crystal device according to the second embodiment, a contact hole 115 is provided on the side of the semiconductor layer 1a, and the scanning line 11 and the back light shielding film 6b are electrically connected.

  As shown in FIG. 7, the base insulating film 12 has a thin film thickness between the channel region 1a 'and the back light shielding film 6b. In other words, the back light shielding film 6b is provided at a position closer to the semiconductor layer 1a than the data line 6a. In this case, for example, the second base insulating film 13 or the like is provided below the back surface light shielding film 6b, and the height is adjusted.

  With this configuration, the back light shielding film 6b functions as a gate electrode. Therefore, in the channel region 1a ', the two gate electrodes of the gate electrode 3a in the scanning line 11 and the gate electrode by the back surface light shielding film 6b are disposed to face each other. That is, the TFT 30 in this embodiment has a so-called double gate structure.

  When the TFT 30 has a double gate structure, a channel can be formed on both the upper layer side and the lower layer side of the channel region 1a '. As a result, as compared with the case where the channel is formed only on the upper layer side of the channel region 1a ′ as in the first embodiment described above, the current flowing in the channel region when the TFT 30 is turned on (that is, the on-state) Current) can be increased. Therefore, it is possible to display a higher quality image. When the back surface light-shielding film 6b functions as a gate electrode in this way, as shown in the figure, the back surface light-shielding film 6b should not be applied to the data line side LDD region 1b and the pixel electrode side LDD region 1c. desirable.

  In the second embodiment, since the back light shielding film 6b is closer to the channel region 1a ′ than in the first embodiment, it is possible to more effectively shield light incident on the channel region 1a ′. . In addition, the presence of the conductive material embedded in the contact hole 115 can improve the light shielding performance on the sides of the semiconductor layer 1a (upper and lower sides in FIG. 6). From this point of view, the contact hole 115 is preferably filled with a plug made of a light-shielding conductive material such as titanium.

  In FIG. 8, when the back surface light-shielding film 6b functions as a gate electrode as described above, the gate electrode 3a in the scanning line 11 may not be provided. That is, only the gate electrode by the back surface light shielding film 6b may be provided. In such a configuration, the effect of the double gate structure described above cannot be obtained, but the TFT can be reliably controlled by the gate electrode formed by the back surface light-shielding film 6b.

  As described above, according to the liquid crystal device according to the second embodiment, in addition to the effect in the first embodiment described above, the effect of displaying a higher quality image or increasing the degree of freedom of the configuration of the TFT 30 is achieved. It is possible to obtain.

<Electronic equipment>
Next, the case where the liquid crystal device which is the above-described electro-optical device is applied to various electronic devices will be described. FIG. 9 is a plan view showing a configuration example of the projector. Hereinafter, a projector using the liquid crystal device as a light valve will be described.

  As shown in FIG. 9, 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 are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Therefore, 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 image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R and 1110B.

  In addition, since light corresponding to each primary color of 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. 9, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic device Examples include a notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel. Needless to say, the present invention can be applied to these various electronic devices.

  In addition to the liquid crystal devices described in the above embodiments, the present invention includes a reflective liquid crystal device (LCOS), a plasma display (PDP), a field emission display (FED, SED), an organic EL display, and a digital micromirror device. (DMD), electrophoresis apparatus and the like are also applicable.

  The present invention is not limited to the above-described embodiment, 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. In addition, an electronic apparatus including the electro-optical device is also included in the technical scope of the present invention.

1 is a schematic plan view illustrating a configuration of a liquid crystal device according to a first embodiment. It is the HH 'sectional view taken on the line of FIG. FIG. 2 is an equivalent circuit diagram of various elements, wirings, and the like in a plurality of pixels formed in a matrix that forms an image display region of the liquid crystal device according to the first embodiment. It is a top view of the pixel part of the liquid crystal device concerning a 1st embodiment. FIG. 5 is a cross-sectional view taken along line A-A ′ of FIG. 4. It is a top view of the pixel part of the liquid crystal device concerning a 2nd embodiment. FIG. 7 is a sectional view taken along line B-B ′ of FIG. 6. It is sectional drawing which shows the modification of the liquid crystal device which concerns on 2nd 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, 3a ... Gate electrode, 6a ... data line, 9a ... pixel electrode, 10 ... TFT array substrate, 10a ... image display area, 11 ... scanning line, 12 ... base insulating film, 30 ... TFT, 71 ... capacitive electrode, 75 ... capacitive insulating film

Claims (10)

A substrate,
A data line provided on the substrate;
A scanning line provided on an upper layer side of the data line and intersecting the data line;
A pixel electrode provided on an upper layer side of the scanning line and provided for each pixel defined corresponding to an intersection of the data line and the scanning line;
A capacitor electrode provided on the lower layer side of the pixel electrode so as to face the pixel electrode through a capacitor insulating film;
A data line side source / drain region electrically connected to the data line and a pixel electrode side source electrically connected to the pixel electrode, which is provided on an upper layer side of the data line and on a lower layer side of the scanning line. And a semiconductor layer having a drain region and a channel region disposed so as to be opposed to a gate electrode formed of a part of the scanning line or electrically connected to the scanning line through a gate insulating film. Electro-optical device characterized.   The electro-optical device according to claim 1, wherein the data line functions as a light-shielding film that shields light incident from the substrate side.   3. The electro-optical device according to claim 1, further comprising a back-surface light-shielding film provided in the same layer as the data line so as to cover the channel region when viewed in plan on the substrate.   The back surface light-shielding film is provided at least partially opposite to the channel region via another gate insulating film provided on the lower layer side of the semiconductor layer, and the channel region is formed from above and below together with the gate electrode. 4. The electro-optical device according to claim 3, wherein the electro-optical device functions as another gate electrode to be sandwiched.   4. The electro-optical device according to claim 3, wherein the back-side light shielding film functions at least partially as the gate electrode facing the channel region from the lower layer side through the gate insulating film.   The electro-optical device according to claim 5, wherein the gate electrode is connected to the scanning line through a contact hole provided on a side of the semiconductor layer. The scanning line is
The gate electrode locally accessing the channel region as the part;
5. The portion adjacent to the gate electrode is stacked on the semiconductor layer via an interlayer insulating film that is thicker than the gate insulating film. 6. Electro-optic device.   The electro-optical device according to claim 1, wherein the capacitor electrode functions as a shield layer that prevents coupling between the pixel electrode and a lower layer side of the capacitor electrode.   9. The semiconductor device according to claim 1, further comprising a counter substrate that is disposed to face the pixel electrode side of the substrate and sandwiches an electro-optic material between the substrate and the substrate. The electro-optical device according to Item.   An electronic apparatus comprising the electro-optical device according to claim 1.

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