JP2010128421A - Electrooptical device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device, such as a liquid crystal device, which is enhanced in quality of image display while a layout of a layered structure is made efficient. <P>SOLUTION: The electrooptical device has, on a substrate (10), a plurality of pixel electrodes, a thin-film transistor (30), a first conduction portion (71) formed on a lower-layer side of the pixel electrodes, constituting at least a part of wiring, an electrode, and an electronic element for performing an electrooptical operation in a pixel region, and having an opening region or notched (5a) by pixel, and a second conduction portion (8) arranged in the opening region or notched region, and relaying and connecting the pixel electrode and a drain region to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electro-optical device such as a liquid crystal device in which a thin film transistor is arranged for each pixel as a switching element on an element substrate, a manufacturing method thereof, and an electronic apparatus such as a liquid crystal projector including the electro-optical device. About.

  In this type of electro-optical device, a pixel electrode, a scanning line for selectively driving the pixel electrode, a data line, and a TFT (Thin Film Transistor) as a pixel switching element are provided on a substrate. Thus, the active matrix driving is possible. Here, in the active matrix driving, the operation of the TFT is controlled by supplying a scanning signal to the scanning line, and an image signal is supplied to the data line at a timing when the TFT is turned on. Display is realized. In such an electro-optical device, a storage capacitor may be provided between the TFT and the pixel electrode in order to increase the contrast of the display image. For example, Patent Document 1 discloses a technique for ensuring an aperture ratio (that is, transmittance) by configuring a storage capacitor from a pair of transparent electrodes that are opposed to each other with a capacitor insulating film interposed therebetween.

Japanese Patent Laid-Open No. 6-148684

  However, according to the background art described above, when the pixel electrode and the drain region are arranged in separate layers, it is necessary to form a deep contact hole for electrically connecting the pixel electrode and the drain region. . When the contact hole is formed deeply, defects and the like are generated in the contact hole forming process, and the conductivity of the contact hole is lowered. In addition, it is extremely difficult to form a deep contact hole only in a narrow region, and it is not suitable for miniaturization. In particular, if there is a defect or the like in a contact hole connecting between the pixel electrode and the drain region to which the image signal potential is applied, noise and noise are mixed in the image signal, and the quality of the display image is deteriorated. .

  The present invention has been made in view of the above-described problems, for example, and an electro-optical device in which a laminated structure is efficiently laid out and capable of displaying a high-quality image, and an electronic device including such an electro-optical device. It is an object to provide a device.

  In order to solve the above problems, the electro-optical device of the present invention is provided on a substrate with a plurality of pixel electrodes, a thin film transistor provided for each of the plurality of pixel electrodes, and a lower layer side than the pixel electrode, The pixel region in which the pixel electrodes are arranged constitutes at least a part of wiring, electrodes, and electronic elements for performing an electro-optical operation, and an opening region or a notch region for each pixel when viewed in plan on the substrate And a second conductive layer for relay connection between the pixel electrode and the drain region of the thin film transistor. A conductive portion.

  In the electro-optical device according to the present invention, for example, an electro-optical material such as liquid crystal is sandwiched between a pair of substrates, and an electro-optical operation such as image display is performed by controlling the alignment state of the liquid crystal.

  On the substrate, for example, wirings such as scanning lines and data lines, and electronic elements such as pixel switching TFTs are stacked as necessary while being insulated from each other through an insulating film, thereby driving the pixel electrodes. The circuit for this is comprised, and the image electrode is arrange | positioned at the upper layer side. During the operation of the electro-optical device, for example, the switching operation of the pixel switching TFT electrically connected to the pixel electrode is controlled through the scanning line, and an image signal is supplied through the data line. A voltage corresponding to the image signal is applied to the pixel electrode via the. As a result, it is possible to display an image in a pixel region or a pixel array region (or also referred to as an “image display region”) in which a plurality of pixel electrodes are arranged.

  The first conductive portion is formed on a lower layer side than the pixel electrode, and constitutes at least a part of a wiring, an electrode, and an electronic element for performing an electro-optical operation in a pixel region in which the pixel electrode is arranged. For example, the first conductive portion is formed as one electrode of a pair of capacitor electrodes constituting an additional capacitor electrically connected to the data line. Further, the first conductive portion has an opening region or a cutout region for each pixel when viewed in plan on the substrate. For example, the first conductive portion is formed in a solid shape over the entire pixel region, and an opening region is formed so that a certain region is opened for each pixel (that is, a hole is formed for each pixel). May be. The first conductive portion is formed as a plurality of island-shaped conductive portions arranged for each pixel, and each of the island-shaped conductive portions extends from a part of the end portion to the inside of the conductive portion. You may have the notch area | region in which the opening area | region was partially formed toward the direction. Thus, by providing an opening region or a notch region in the first conductive portion, each of the pixel electrodes arranged for each pixel is placed on the lower layer side of the first conductive portion via the opening region or the notch region. It can be electrically connected to the formed element or wiring.

  Particularly in the present invention, the pixel electrode and the drain region of the thin film transistor are electrically connected by forming a second conductive portion described below in the opening region or the cutout region. In other words, by forming the second conductive portion in the opening region or notch, the first conductive portion formed on the lower layer side of the pixel electrode and the pixel electrode are electrically insulated from each other, and the pixel electrode outputs from the drain region. The image signal potential thus obtained can be supplied. Accordingly, the pixel electrode can be driven on / off while using the first conductive portion provided on the lower layer side of the pixel electrode as a wiring, an electrode, and an electronic element for performing an electro-optical operation. An electro-optical device having a typical wiring layout can be realized.

  In addition, it is possible to effectively improve the wiring layout on the substrate by relay-connecting the pixel electrode and the drain region with the second conductive portion in this way. If the pixel electrode and the drain region are directly connected without forming a relay layer such as the second conductive portion, the pixel electrode and the drain region may be connected with each other in order to prevent light from being applied to the drain region of the semiconductor layer. The contact hole to be connected needs to be formed in a region where the display term is not transmitted in the image display region (hereinafter, referred to as a non-transmissive region as appropriate). Furthermore, in this case, it is necessary to devise the shape so that a part of the pixel electrode extends to the non-transmissive region so that the pixel electrode can be connected to the contact hole. That is, if the second conductive portion is not provided, the wiring layout on the substrate is thus significantly limited. On the other hand, when the second conductive portion is formed as in the present invention, a contact hole for connecting the second conductive portion and the drain region may be provided in the non-transmissive region, and between the second conductive portion and the pixel electrode. The contact hole for forming the light source may be disposed in a non-transmissive region, or may be disposed in a region (hereinafter, appropriately referred to as a transmissive region) through which display light is transmitted in the image display region. In particular, when the contact hole is disposed in the transmissive region, it is not necessary to devise the shape of the pixel electrode as described above. Accordingly, by forming a contact hole for connecting the drain region and the second conductive portion in the non-transmissive region, the second conductive portion and the pixel electrode can be connected while maintaining the light shielding property of the semiconductor layer. This greatly expands the range in which contact holes can be placed, and the wiring design layout is greatly improved.

  When a contact hole for connecting the second conductive portion and the pixel electrode is formed in the transmissive region, a transparent conductive material such as ITO is used to prevent a decrease in transmittance in the image display region. Preferably it is formed.

  In addition, by connecting the pixel electrode and the drain region via the second conductive portion, even if a thick interlayer insulating film is formed between the pixel electrode and the drain region, the contact having good conductivity is provided. It can be connected using a hole. In other words, if the pixel electrode and the drain region are directly connected through a deeply formed contact hole, defects or the like are generated in the manufacturing process inside the contact hole that should have good conductivity. However, it is technically difficult to form such a deep contact hole. In that respect, as in the present invention, by providing a second conductive portion for relay connection, a two-stage contact hole is connected between the pixel electrode and the drain region (that is, between the pixel electrode and the second conductive portion). And a contact hole connecting between the second conductive portion and the drain region). Therefore, since the pixel electrode and the drain region can be electrically connected using a contact hole having a relatively shallow depth, an error or an error is caused by noise mixed in the image signal potential applied to the pixel electrode. This can be prevented and the quality of the display image can be improved.

  As described above, according to the present invention, the electrical connection between the pixel electrode and the drain region is achieved by arranging the second conductive portion as a relay wiring in the opening region or the cutout region provided in the first conductive portion. This can be realized with an efficient wiring layout, and the degree of freedom of the wiring layout can be greatly increased. Further, by arranging the second conductive portion for performing the relay connection, the depth of the contact hole necessary for the electrical connection between the pixel electrode and the drain region can be reduced, so that noise to the image signal is reduced. Therefore, it is possible to realize an electro-optical device capable of suppressing the mixing of the image and displaying a good image.

  In one aspect of the present invention, the second conductive portion includes a portion made of the same film as the first conductive portion.

  The “same film” in this embodiment means films formed on the same occasion in the manufacturing process of the electro-optical device, and are the same type of film. That is, the second conductive part is a film formed on the same occasion as the first conductive part in the manufacturing process. Note that “consisting of the same film” according to the present invention does not mean that it is continuous as a single film, but basically is a part of the same film that is separated from each other. That is enough. For example, the first conductive part is one of a pair of capacitive electrodes forming a storage capacitor, and the second conductive part is a relay wiring between the pixel electrode and the drain region that are electrically insulated from the first conductive part. In addition, they may be separated from each other. Furthermore, the first conductive portion and the second conductive portion do not necessarily have a film-like structure. For example, the second conductive portion is integrated with a contact hole connecting the pixel electrode and the drain region in a three-dimensional manner. It may have a typical structure.

  Thus, by forming the first conductive portion and the second conductive portion in a specific process in the manufacturing process, not only can the manufacturing cost be reduced, but also the wiring layout can be simplified or improved in efficiency. it can.

  In another aspect of the electro-optical device of the present invention, the electro-optical device further includes a drain relay portion for relay connection between the second conductive portion and the drain region.

  According to this aspect, between the pixel electrode and the drain region, the two types of relay portions and the relay wiring, that is, the drain relay portion and the second conductive portion in the present invention are formed. That is, the drain relay portion is formed so as to electrically connect the drain region and the second conductive portion. In this manner, by adding the drain relay portion between the second conductive portion and the drain region, the depth of the contact hole necessary for connecting the pixel electrode and the drain region can be further reduced. As a result, a high-quality contact hole with fewer defects and good conductivity can be formed, so that noise and deterioration are less likely to occur in the image signal potential supplied to the pixel electrode. Therefore, it is possible to realize an electro-optical device capable of displaying a good image.

  In the above aspect including the drain relay portion, the second conductive portion and the drain relay portion are interposed via the first contact hole filled with the same transparent conductive material as that constituting the second conductive portion. Are electrically connected.

  In this aspect, by forming the second conductive portion and the drain relay portion with a transparent conductive material, it can be arranged in the transmission region. That is, by forming the transparent material in this way, the transmittance is not lowered even if the transparent light is arranged in the transmission region. As a result, the degree of freedom of wiring layout in the laminated structure formed on the substrate can be further improved.

  Furthermore, the drain relay portion and the drain region may be electrically connected via a second contact hole disposed in a non-transmissive region of the pixel region as viewed in plan on the substrate.

  The semiconductor layer of the thin film transistor including the drain region is disposed in the non-transmissive region because a light leakage current is generated when light is irradiated to cause a malfunction. In this aspect, the contact hole that electrically connects the drain region and the drain region is disposed in a non-transmissive region where light does not enter from the outside of the substrate. By disposing the contact hole in the non-transmissive region in this manner, it is possible to prevent light from entering the semiconductor layer, thereby suppressing generation of light leakage current and stabilizing the operation of the thin film transistor.

  In another aspect of the electro-optical device of the present invention, the pixel electrode and the first conductive portion are disposed to face each other via a capacitor insulating film, thereby forming a storage capacitor.

  According to this aspect, by using the first conductive portion and the pixel electrode as they are as a pair of capacitor electrodes, a storage capacitor can be additionally formed without complicating the stacked structure formed on the substrate. For example, a storage capacitor connected to a pixel electrode to which an image signal is supplied can be formed by supplying a fixed potential to the first conductive portion formed on the lower layer side of the pixel electrode from a power supply line or the like. As a result, for example, the holding capacitance is added to the wiring capacitance of the wiring to which the image signal is applied, or the capacitance caused by the overlap with other wiring, so that the potential that the original image signal should have varies. That is, it is possible to suppress the push-down of the image signal potential written to the pixel electrode. As a result, it is possible to reduce or prevent the occurrence of display unevenness along, for example, the data line due to the push-down of the image signal potential written to the pixel electrode.

  Note that the capacitance value of the storage capacitor may be increased or decreased by appropriately adjusting the thickness of the dielectric film formed between the first conductive portion and the pixel electrode and the area of the opposing capacitor electrode.

  In addition, since it is not necessary to additionally form a conductive layer for the capacitor electrode in order to form the storage capacitor, the stacked structure does not have to be complicated. As a result, the manufacturing cost of the electro-optical device can be reduced and the overall size of the electro-optical device can be reduced, and a high-definition electro-optical device can be realized.

  In another aspect of the electro-optical device of the present invention, the pixel electrode, the first conductive portion, and the second conductive portion are all made of ITO (Indium Tin Oxide).

  According to this aspect, the pixel electrode, the first conductive portion, and the second conductive portion are all made of ITO. Since ITO is a transparent conductive material, it is used for the pixel electrode arranged for each pixel and the first conductive portion and the second conductive portion formed on the lower layer side of the pixel electrode. Good signal transmission can be realized without reducing the rate. In this manner, by forming the pixel electrode, the first conductive portion, and the second conductive portion from ITO, an electro-optical device having high transmittance and capable of displaying a high-quality image can be realized.

  In addition, since ITO has a relatively large resistance value compared to a metal material such as aluminum, the first conductive portion and the second conductive portion formed of ITO are formed as elements that do not require high-speed operation. It is preferable. Therefore, for example, it may be formed as a capacitor electrode to which a fixed potential as described above is applied.

  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 it includes the electro-optical device of the present invention described above, a projection display device, a television, a mobile phone, an electronic notebook, a word processor, capable of performing high-quality image display, Various electronic devices such as 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. In addition, as an electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper, an electron emission device (Field Emission Display and Conduction Electron-Emitter Display), and a display device using these electrophoretic device and electron emission device Is also possible.

  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.

<1. Liquid crystal device>
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 when the TFT array substrate 10 is viewed from the counter substrate 20 side together with each component formed thereon, and FIG. 2 is a plan view of FIG. It is HH 'sectional drawing.

  1 and 2, the liquid crystal device according to the present embodiment includes a TFT array substrate 10 and a counter substrate 20 that are arranged to face each other. The TFT array substrate 10 is, for example, a transparent substrate such as a quartz substrate or a glass substrate, or a silicon substrate. The counter substrate 20 is also a 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 sealed around the image display region 10a where the electro-optical operation is performed. They are bonded to each other by a sealing material 52 provided in the region.

  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.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area 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, 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 on the TFT array substrate 10.

  In the peripheral region on the TFT array substrate 10, a data line driving circuit 101 and a plurality of external circuit connection terminals 102 are provided along one side of the TFT array substrate 10 on the outer peripheral side of 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. A 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 is formed in which wirings such as TFTs for pixel switching, scanning lines, and data lines are formed. In the image display area 10a, pixel electrodes 9 are provided in a matrix form on the upper layer of wiring such as pixel switching TFTs, scanning lines, and data lines. The pixel electrode 9 is formed as a transparent electrode made of an ITO film. An alignment film 16 is formed on the pixel electrode 9.

  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. On the light shielding film 23 (below the light shielding film 23 in FIG. 2), the counter electrode 21 made of an ITO film is formed, for example, in a solid shape so as to face the plurality of pixel electrodes 9, and further on the counter electrode 21 (FIG. 2, below the counter electrode 21), an alignment film 22 is formed.

  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 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, the electrical configuration of the image display area 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 switching TFT 30 as an example of the “thin film transistor” according to the present invention is formed in each of a plurality of pixels formed in a matrix form constituting the image display region 10 a. . The TFT 30 is electrically connected to the pixel electrode 9, and performs switching control of the pixel electrode 9 when the liquid crystal device according to the present embodiment operates. The data line 6 to which the image signal is supplied is electrically connected to the source region of the TFT 30. Image signals S1, S2,..., Sn to be written to the data lines 6 may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6. Good.

  The scanning line 11 is electrically connected to the gate of the TFT 30, and the liquid crystal device according to the present embodiment applies the scanning signals G1, G2,..., Gm to the scanning line 11 in a pulsed manner at a predetermined timing. It is configured to apply in a line sequential order. The pixel electrode 9 is electrically connected to the drain of the TFT 30, and the image signal S1, S2,..., Sn supplied from the data line 6 is obtained by closing the switch of the TFT 30 serving as a switching element for a certain period. It is written at a predetermined timing. A predetermined level of image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9 is constant between the counter electrode 21 (see FIG. 2) formed on the counter substrate 20 (see FIG. 2). Hold for a period.

  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 9 and the counter electrode 21 (see FIG. 2). ing.

  Next, in the liquid crystal device according to the present embodiment, a specific stacked structure in the image display region 10a will be described in detail.

  FIG. 4 is a schematic diagram transparently showing the positional relationship between electrodes and wirings arranged for performing an electro-optical operation in the image display region 10a of the liquid crystal device according to the present embodiment. In FIG. 4, in order to make each layer and each member recognizable on the drawing, the scale is different for each layer and each member.

  On the TFT array substrate 10, scanning lines 11 and data lines 6 are arranged along the X direction and the Y direction, respectively. The TFTs 30 (that is, the semiconductor layers 30 a and A gate electrode 30b) is formed. The scanning line 11 is made of a light-shielding conductive material, for example, W (tungsten), Ti (titanium), TiN (titanium nitride) or the like, and is wider than the semiconductor layer a so as to include the semiconductor layer 30a of the TFT 30. Is formed. Here, as will be described later, since the scanning line 11 is arranged on the lower layer side than the semiconductor layer 30 a, the TFT array substrate 10 is formed by forming the scanning line 11 wider than the semiconductor layer 30 a of the TFT 30 in this way. The channel region 30b of the TFT 30 can be almost or completely shielded from the return light, such as the back-surface reflection of light and the light emitted from other liquid crystal devices by a multi-plate projector or the like and penetrating the composite optical system. As a result, the light leakage current in the TFT 30 is reduced during the operation of the liquid crystal device, the contrast ratio can be improved, and high-quality image display can be performed.

  The TFT 30 includes a semiconductor layer 30a and a gate electrode 30b. The semiconductor layer 30a is formed including a source region 30a1, a channel region 30a2, and a drain region 30a3. Here, an LDD (Lightly Doped Drain) region may be formed at the interface between the channel region 30a2 and the source region 30a1 or between the channel region 30a2 and the drain region 30a3.

  The gate electrode 30b is formed through a gate insulating film in a region overlapping the channel region of the semiconductor layer 30a when viewed in plan on the TFT array substrate 10. Although not shown in FIG. 4, the gate electrode 30b is electrically connected to the scanning line 11 arranged on the lower layer side via the contact hole 34, and the TFT 30 is formed by applying a scanning signal. ON / OFF control.

  The source region 30 a 1 of the TFT 30 is electrically connected to the data line 6 formed on the upper layer side through the contact hole 31. On the other hand, the drain region 30a3 is electrically connected to the pixel electrode 9 via the first drain relay wiring (omitted in FIG. 4) and the second drain relay wiring (omitted in FIG. 4) formed in the contact holes 32 and 33. It is connected. As will be described later, in particular, since the contact hole 33 and the second drain relay wiring are formed of ITO, which is a transparent conductive material, they are arranged in the transmissive region of the pixel display region 10a.

  The pixel electrode 9 is formed in an island shape for each pixel. In the present embodiment, each pixel is divided into a matrix by the data lines 6 and the scanning lines 11. Then, as indicated by the dotted line 9 a in FIG. 4, the pixel electrode 9 is part of the data line 6 and the scanning line 11 when the end of the pixel electrode 9 is viewed on the TFT array substrate 10 in each pixel. Are arranged so as to overlap each other.

  Next, the laminated structure in the cross section taken along the line AA ′ of FIG. 4 will be described with reference to FIG. On the TFT array substrate 10, the scanning line 11 described above is formed wider than the semiconductor layer 30a of the TFT 30 formed on the upper layer side. The scanning line 11 is covered with a base insulating film 12, and the surface thereof is flattened. The underlying insulating film 12 also has a function of preventing changes in the characteristics of the TFT 30 for pixel switching due to roughness during the surface polishing of the TFT array substrate 10 and dirt remaining after cleaning.

  The TFT 30 includes a semiconductor layer 30a (that is, a source region 30a1, a channel region 30a2, and a drain region 30a3) and a gate electrode 30b. In particular, the gate electrode 30b is made of, for example, conductive polysilicon, and is electrically connected to the scanning line 11 through a contact hole (not shown in FIG. 5) opened in the gate insulating film 13.

  The data line 6 to which the image signal is supplied is electrically connected to the source region 30a1 through the contact hole 31 opened in the gate insulating film 13 and the first interlayer insulating film 14. On the other hand, the drain region 30a3 is electrically connected to the pixel electrode 9 formed on the upper layer side. More specifically, the drain region 30 a 3 is opened in the first drain relay wiring 7 formed in the contact hole 32 opened in the gate insulating film 13 and the first interlayer insulating film 14 and the second interlayer insulating film 15. The pixel electrode 9 is electrically connected via the second drain relay wiring 8 formed in the contact hole 33.

  A capacitor electrode 71 is formed on the lower layer side of the pixel electrode 9 with a capacitor insulating film 72 interposed therebetween. That is, the storage capacitor 70 is formed by sandwiching the capacitor insulating film 72 between the pixel electrode 9 and the capacitor electrode 71. By thus providing the storage capacitor 70 integrally with the pixel electrode 9, it is possible to hold the voltage of the pixel electrode 9 for a time that is, for example, three orders of magnitude longer than the time during which the image signal is actually applied. It becomes. As a result, the liquid crystal device having a high contrast ratio can be realized as a result of improving the holding characteristics of the liquid crystal element.

  In the present embodiment, the pixel electrode 9, the capacitor electrode 71, and the second drain relay wiring 8 are all made of ITO. Since ITO is a transparent conductive material, it is used for the pixel electrode 9 disposed in the opening region of the image display region 10a and the capacitor electrode 71 formed on the lower layer side of the pixel electrode, so that the transmittance of the liquid crystal device can be obtained. The image signal can be transmitted satisfactorily without lowering the image quality, and high-quality image display can be realized. Further, by forming the capacitor electrode 71 and the second drain relay wiring 8 with the same material as the pixel electrode 9, the manufacturing process of the liquid crystal device can be simplified, and conductive materials having different ionization tendencies are in contact with each other. By doing so, it is also possible to prevent the occurrence of electrolytic corrosion that occurs during manufacturing.

  In addition, since the second drain relay wiring 8 including the contact hole 33 is formed of ITO, which is a transparent conductive material, the contact hole 33 transmits light in the pixel region as shown in FIG. It can be provided in the transmission region. Thus, even if the contact hole 33 is arranged in the transmissive region, the transmittance of the liquid crystal device is not lowered because it is formed of a transparent conductive material. Therefore, the degree of freedom of the wiring layout in the stacked structure can be significantly improved as compared with the case where the contact hole is formed in the non-transmissive region with a non-transparent conductive material in order not to reduce the transmittance of the liquid crystal device. .

  On the other hand, the semiconductor layer 30a including the drain region 30a3 is disposed in the non-transmissive region because light leakage current is generated when light is irradiated to cause malfunction. If the contact hole 32 is disposed in the transmissive region, the drain region 30a3 directly connected to the contact hole 32 is also exposed to the transmissive region, and a light leakage current is generated. It is arranged in a non-transmission area where light does not enter (that is, it overlaps the scanning line 11 in plan view).

  The capacitor electrode 71 and the second drain relay wiring 8 in the present embodiment are made of the same film. That is, the capacitor electrode 71 and the second drain relay wiring 8 are the same type of film formed on the same occasion in the manufacturing process of the liquid crystal device according to the present embodiment. By forming the capacitor electrode 71 and the second drain relay wiring 8 from the same film in this way, both can be formed together in a specific process in the manufacturing process, so that the manufacturing cost can be further reduced and the wiring can be reduced. It can also contribute to the simplification or efficiency of the layout.

  Since ITO has a relatively large resistance value compared to a metal material such as aluminum, there is a risk that the propagation of an electric signal may be delayed when used in an element that requires high-speed operation. In the case where the capacitor electrode 71 is not required to operate at high speed as in the embodiment, there is no such fear.

  Although not shown in FIG. 5, an alignment film that regulates the alignment state of the liquid crystal 50 is laminated on the pixel electrode 9.

  Next, with reference to FIG. 6, the structure of the capacitor electrode 71 and the second drain relay wiring 8 formed on the TFT array substrate 10 will be described in detail.

  FIG. 6 is a schematic diagram showing the arrangement of the capacitor electrode 71 and the second drain relay wiring 8 on the TFT array substrate 10 together with the data lines 6 and the scanning lines 11. In FIG. 6, for convenience of explanation, the data line 6 and the scanning line 11 formed on the lower layer side of the capacitor electrode 71 and the second drain relay wiring 8 are transparently shown, and each layer and each member are recognized on the drawing. In order to make the size as large as possible, the scale is different for each layer and each member.

  The data line 6 and the scanning line 11 extend in the Y direction and the X direction, respectively. Each pixel is divided by a data line 6 and a scanning line 11. The capacitor electrode 71 as the “first conductive portion” of the present invention is formed on the lower layer side than the pixel electrode 9 (not shown in FIG. 6), and has an opening region 5a for each pixel. A second drain relay wiring 8 that electrically connects the pixel electrode 9 and the drain region 30a3 is formed integrally with the contact hole 33 inside the opening region 5a. That is, by forming the relay wiring in the opening region 5a provided for each pixel in this way, the pixel electrode 9 can be electrically connected to the drain region 30a3 of the TFT 30 formed on the lower layer side of the capacitor electrode 71. Has been. Accordingly, by providing the second drain relay wiring 8 in the opening region 5a, the drain electrode 30a3 outputs to the pixel electrode 9 without being electrically short-circuited to the capacitor electrode 71 formed on the lower layer side of the pixel electrode 9. An image signal potential can be supplied. As a result, since the pixel electrode 9 can be driven on / off while providing the capacitor electrode 71 on the lower layer side of the pixel electrode 9, a liquid crystal device having an extremely efficient wiring layout can be realized.

  In this embodiment, since the capacitor electrode 71 and the second drain relay wiring 8 are formed on the lower layer side of the pixel electrode 9, a transparent conductive material is used so as not to cause a decrease in the transmittance of the liquid crystal device. It is made of ITO.

  Here, as shown in FIG. 5, in the present embodiment, the pixel electrode 9 and the drain region 30a are electrically connected via two relay lines (that is, the first drain relay line 7 and the second drain relay line 8). Connected. If an attempt is made to directly connect the pixel electrode 9 and the drain region 30a3, the thickness of the insulating film (that is, the gate insulating film 13, the first interlayer insulating film 14, and the second interlayer insulating film) existing between the two layers is large. Therefore, it is difficult to make a good electrical connection. In other words, since the pixel electrode 9 and the drain region 30a3 are formed in separate layers, when a direct connection is made through a deep contact hole, the manufacturing process of the contact hole that should originally have good conductivity is performed. In this case, defects or the like occur, and the conductivity of the contact hole decreases. In this regard, as in the present embodiment, by providing two relay wirings (that is, the first drain relay wiring 7 and the second drain relay wiring 8), contact holes having a shallow depth (that is, contact holes 32 and 33). The electrical connection between the pixel electrode 9 and the drain region 30a3 can be formed in a good state.

  As described above, according to the present embodiment, the opening region 5a is provided in the capacitor electrode 71, and the relay wiring is formed in the opening region 5a, thereby efficiently connecting the pixel electrode 9 and the drain region 30a3. This can be realized with a typical wiring layout, and at the same time, the degree of freedom of wiring layout can be greatly improved. At the same time, by using a plurality of relay lines, the depth of the contact hole necessary for electrical connection between the pixel electrode 9 and the drain region 30a is reduced, and a contact hole having good conductivity is formed. Can do. As a result, it is possible to realize a liquid crystal device that can perform good image display with little loss of image signal potential and defects.

<Modification>
In the above embodiment, the capacitor electrode 71 is formed on the TFT array substrate 10 in a substantially solid shape (that is, on a solid surface). However, when the capacitance value of the storage capacitor 70 is sufficient, etc., the capacitor electrode 71 is formed in an island shape for each pixel as shown in FIG. 7, and a plurality of capacitor electrodes 71 are dropped to a predetermined potential. It may be configured to be connected to a line. In this case, the respective capacitor electrodes 71 arranged for each pixel are held at a predetermined potential by being electrically connected to each other by, for example, wirings (not shown in FIG. 7) separately provided on the lower layer side. Yes. In this case, if a cutout portion is provided in the capacitor electrode 71 in the region facing the second drain relay wiring 8 instead of the opening region 5a, the vertical conduction through the second drain relay wiring 8 is as described above. This can be realized in the same manner as in the above embodiment.

<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. 8 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. 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 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. 8, 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 spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change, In addition, an electronic apparatus including the electro-optical device is 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 this embodiment. It is HH 'sectional drawing of FIG. It is a circuit diagram which shows the electrical structure of the liquid crystal device which concerns on this embodiment. It is a schematic diagram which shows transparently the positional relationship of wiring etc. in the image display area 10a of the liquid crystal device which concerns on this embodiment. It is AA 'sectional drawing of FIG. It is the schematic diagram which showed transparently the positional relationship of the capacitive electrode and 2nd drain relay wiring on the board | substrate of the liquid crystal device which concerns on this embodiment with a peripheral wiring. It is the schematic diagram which showed transparently the positional relationship of the capacitive electrode and 2nd drain relay wiring on the board | substrate of the liquid crystal device which concerns on a modification with peripheral wiring. It is an example of an electronic apparatus to which the electro-optical device of the present embodiment is applied.

Explanation of symbols

  5a Open area, 6 Data line, 7 First drain relay wiring, 8 Second drain relay wiring, 9 Pixel electrode, 10 TFT array substrate, 10a Image display area, 11 Scan line, 12 Base insulating film, 30 TFT, 30a Semiconductor Layer, 30a1 source region, 30a2 channel region, 30a3 drain region, 30b gate electrode, 50 liquid crystal, 70 storage capacitor, 71 capacitor electrode, 72 capacitor insulating film

Claims (8)

On the board
A plurality of pixel electrodes;
A thin film transistor provided for each of the plurality of pixel electrodes;
It is arranged on the lower layer side of the pixel electrode, and constitutes at least a part of a wiring, an electrode, and an electronic element for performing an electro-optical operation in a pixel region in which the pixel electrode is arranged, and is planar on the substrate. A first conductive portion having an opening region or a notch region for each pixel as viewed in FIG.
A second conductive portion that is disposed in the opening region or the cutout region when viewed in plan on the substrate, and for relay connection between the pixel electrode and the drain region of the thin film transistor. An electro-optical device.   The electro-optical device according to claim 1, wherein the second conductive portion includes a portion made of the same film as the first conductive portion.   The electro-optical device according to claim 1, further comprising a drain relay portion for relay connection between the second conductive portion and the drain region.   The second conductive part and the drain relay part are electrically connected via a first contact hole filled with the same transparent conductive material that constitutes the second conductive part. The electro-optical device according to claim 3.   The drain relay portion and the drain region are electrically connected through a second contact hole disposed in a non-transmissive region of the pixel region as viewed in plan on the substrate. The electro-optical device according to claim 3.   6. The electro-optical device according to claim 1, wherein the pixel electrode and the first conductive portion are disposed to face each other with a capacitive insulating film therebetween, thereby forming a storage capacitor.   7. The electro-optical device according to claim 1, wherein each of the pixel electrode, the first conductive portion, and the second conductive portion is made of ITO (Indium Tin Oxide).   An electronic apparatus comprising the electro-optical device according to claim 1.

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