JP2010117402A - Electro-optical device, electronic apparatus, and method of manufacturing electro-optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To display a high quality image by improving a covering rate of an alignment layer in an electro-optical device such as a liquid crystal device. <P>SOLUTION: The electro-optical device includes: a substrate (10); an insulating film (210) formed on the substrate and provided with an engraved part (215) having steep sidewalls (215a, 215b) at a predetermined angle with respect to the substrate face; a plurality of pixel electrodes (9a) formed in an overlay side of the insulating film and having an inclined end, disposed as at least partially overlapping the sidewalls in a plan view on the substrate; and an alignment layer (16) formed on the plurality of pixel electrodes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  As an electro-optical device of this type, for example, an electro-optical material such as liquid crystal is disposed opposite to the pixel electrode through an alignment film, and an image is displayed by controlling the electro-optical material by applying a voltage to the pixel electrode. There is something to do. In such an electro-optical device, the alignment ratio of the alignment film to the pixel electrode (in other words, adhesion) may be deteriorated, resulting in an alignment failure of the electro-optical material. For this reason, for example, Patent Document 1 proposes a technique of tapering the pixel electrode by ion implantation and wet etching.

JP 2003-222894 A

  However, in the technique described above, since the pixel electrodes are patterned by wet etching, for example, the gaps between the pixel electrodes are made fine by increasing the aperture ratio in the pixels (that is, increasing the ratio of openings through which light passes). It is extremely difficult to cope with the process. In other words, the above-described technique has a technical problem that there is a risk of inconvenience in realizing downsizing and high definition of the apparatus.

  The present invention has been made in view of, for example, the above-described problems. An electro-optical device and an electronic apparatus that can display a high-quality image by improving the coverage of the alignment film, and a method for manufacturing the electro-optical device It is an issue to provide.

  In order to solve the above problems, an electro-optical device according to an aspect of the invention is provided with a substrate and an insulating portion formed on the substrate and provided with a dug lower portion having a side wall standing at a predetermined angle with respect to the surface of the substrate. A plurality of pixel electrodes formed on an upper layer side of the film and the insulating film and having end portions inclined by being provided so as to at least partially overlap the side wall when viewed in plan on the substrate And an alignment film formed on the plurality of pixel electrodes.

  According to the electro-optical device of the present invention, during the operation, an image signal is supplied to the plurality of pixel electrodes formed on the substrate, so that the electro-optical material arranged to face each other through the alignment film is controlled. . As a result, an image is displayed in a pixel region in which a plurality of pixel electrodes are arranged. More specifically, for example, in the pixel region, in addition to the above-described pixel electrode, a transistor for controlling supply of an image signal to the pixel electrode is provided, and the scanning signal is supplied from the scanning line to the transistor. In addition, the supply of the image signal from the data line to the pixel electrode is controlled. Thereby, image display by a so-called active matrix method is performed.

  An insulating film that insulates the pixel electrode from other conductive layers is formed on the lower layer side of the pixel electrode. The insulating film is provided with a digging portion having a side wall that stands up at a predetermined angle with respect to the surface of the substrate. That is, a groove-shaped or hole-shaped recess is provided on the insulating film. Here, the “predetermined angle” typically refers to an angle close to 90 degrees, but in a broad sense, the side wall is not parallel to the substrate surface. Therefore, the present invention includes a case where the sidewall is formed obliquely (for example, 45 degrees) with respect to the substrate surface. The digging lower portion is provided, for example, by performing a patterning process by etching on an insulating film flattened after film formation.

  Since the insulating film is provided with the digging lower portion, a step due to the side wall of the digging lower portion is generated in the layer formed on the upper layer side of the insulating film. In the present invention, in particular, the plurality of pixel electrodes formed on the upper layer side of the insulating film are formed so that their end portions at least partially overlap the side walls of the insulating film. In other words, the dug portion is provided at a position where the side wall overlaps the end portion of each pixel electrode. Thereby, the edge part of a some pixel electrode will be in the state inclined under the influence of the level | step difference resulting from the side wall of the dug lower part in an insulating film. That is, the pixel electrode is tapered.

  More specifically, the plurality of pixel electrodes, for example, after forming a film made of ITO or the like on a layer in which a step due to the side wall of the digging portion in the insulating film is formed, a portion inclined by the step, It is formed by patterning by dry etching or the like so as to be an end portion of each pixel electrode (that is, by removing a portion that becomes a gap between the pixel electrodes).

  Particularly in the present invention, since the end portion of the pixel electrode is tapered, the coverage of the alignment film formed on the pixel electrode can be improved. That is, it is possible to prevent an unnecessary gap from being generated between the pixel electrode and the alignment film or a step from being generated on the surface of the alignment film. By improving the coverage of the alignment film, the alignment regulating force for the electro-optical material by the alignment film is strengthened. Therefore, alignment failure of the electro-optic material can be prevented. Accordingly, it is possible to effectively prevent a deterioration in image quality due to poor alignment.

  The pixel electrode is preferably tapered at all ends (that is, all around the pixel electrode), but the effects described above can be obtained accordingly by being partially tapered. Therefore, the dug portion in the insulating film may not be provided so as to overlap all the end portions of the pixel electrode.

  In addition, a conductive layer is typically not formed between the pixel electrode and the insulating film. In this way, it is possible to prevent the conductive layer from being uneven due to the level difference caused by the side wall of the lower portion of the insulating film. Therefore, it is possible to avoid risks such as disconnection in the conductive layer and to prevent unnecessary complication of the laminated structure. Further, since the number of layers existing between the pixel electrode and the insulating film can be reduced, the end portion of the pixel electrode can be more reliably inclined by the step caused by the side wall of the lower portion of the insulating film. That is, it is possible to prevent the step from being relaxed by the presence of the conductive layer between the pixel electrode and the lower portion of the digging, and the end of the pixel electrode from being inclined. Therefore, the coverage of the alignment film with respect to the pixel electrode can be improved more reliably.

  Note that another insulating film may be formed between the pixel electrode and the insulating film. However, in order to incline the edge of the pixel electrode, two or more other insulating films are not included. Is desirable. However, by forming another insulating film between the pixel electrode and the insulating film, the inclination at the end of the pixel electrode can be intentionally made gentle. In the case where another insulating film is formed between the pixel electrode and the insulating film, the inclination at the end of the pixel electrode can be adjusted by providing a digging portion in the other insulating film.

  As described above, according to the electro-optical device of the present invention, the coverage of the alignment film with respect to the pixel electrode can be improved by providing the digging portion in the insulating film formed on the lower layer side of the pixel electrode. Therefore, it is possible to display a high quality image.

  In one aspect of the electro-optical device of the present invention, the plurality of pixel electrodes are formed directly on the insulating film.

  According to this aspect, since the pixel electrode is formed immediately above the insulating film (that is, no other layer is formed between the pixel electrode and the insulating film), the step due to the side wall of the digging portion in the insulating film The end of the pixel electrode can be inclined more reliably. That is, it is possible to prevent the step from being relaxed by the presence of another layer between the pixel electrode and the lower portion of the digging, and the end of the pixel electrode from being inclined. Therefore, the coverage of the alignment film with respect to the pixel electrode can be improved more reliably.

  In another aspect of the electro-optical device of the present invention, end portions of the plurality of pixel electrodes are formed so as to have a convex curved surface on the upper layer side.

  According to this aspect, the insulating film is provided with the digging lower portion, so that the end portion of the pixel electrode has a convex curved surface on the upper layer side. That is, the end portion of the pixel electrode is formed as a curved surface that is rounded and swollen.

  By forming the pixel electrode so as to have a convex curved surface on the upper layer side, it is possible to reduce tight irregularities on the surface of the pixel electrode. That is, the surface of the pixel electrode can be made smoother. Therefore, the coverage of the alignment film with respect to the pixel electrode can be effectively increased.

  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 electro-optical device according to the present invention described above is provided, a projection display device, a television, a mobile phone, an electronic notebook, and a word processor capable of performing high-quality 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. Further, as the electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  In order to solve the above problems, an electro-optical device manufacturing method of the present invention forms an insulating film on a substrate by forming an insulating film provided with a dug lower portion having a side wall standing at a predetermined angle with respect to the surface of the substrate. And forming a plurality of pixel electrodes having inclined edges by being provided so as to at least partially overlap the side wall when viewed in plan on the substrate, on the upper layer side of the insulating film A pixel electrode forming step, and an alignment film forming step of forming an alignment film on the plurality of pixel electrodes.

  According to the method for manufacturing an electro-optical device of the present invention, in the process of forming various conductive layers and interlayer insulating films on the substrate, the digging lower portion having a side wall standing at a predetermined angle with respect to the surface of the substrate is provided. An insulating film is formed. Subsequently, on the upper layer side of the insulating film, a plurality of pixel electrodes having inclined end portions are formed by being provided so as to at least partially overlap the side wall of the dug portion when viewed in plan on the substrate. . At this time, the end portions of the plurality of pixel electrodes are inclined under the influence of the step caused by the side wall of the lower portion of the insulating film. That is, the pixel electrode is tapered. An alignment film for controlling the alignment direction of the electro-optic material is formed on the pixel electrode.

  In the present invention, in particular, it is possible to improve the coverage of the alignment film formed on the pixel electrode in which the end portion of the pixel electrode is tapered. That is, it is possible to prevent an unnecessary gap from being generated between the pixel electrode and the alignment film or a step from being generated on the surface of the alignment film. By improving the coverage of the alignment film, the alignment regulating force for the electro-optical material by the alignment film is strengthened. Therefore, alignment failure of the electro-optic material can be prevented. Accordingly, it is possible to effectively prevent a deterioration in image quality due to poor alignment.

  Incidentally, when the tapered pixel electrode is formed, a patterning process by, for example, dry etching is performed. Here, assuming that the pixel electrode is patterned by wet etching, it becomes extremely difficult to cope with the miniaturization of the gap between the pixel electrodes due to, for example, a high aperture ratio in the pixel.

  However, in the present invention, since the pixel electrodes can be formed by dry etching as described above, it is easy to cope with the miniaturization of the gaps between the pixel electrodes. Therefore, it is extremely advantageous in realizing downsizing and high definition of the apparatus. However, when the gap between the pixel electrodes is relatively large, the pixel electrodes may be formed by wet etching. Alternatively, the pixel electrode may be formed by other methods.

  As described above, according to the method of manufacturing the electro-optical device of the present invention, the coverage of the alignment film with respect to the pixel electrode is improved by providing the dug lower portion in the insulating film formed on the lower layer side of the pixel electrode. Can do. Therefore, it is possible to manufacture an electro-optical device that can display a high-quality image.

  In another aspect of the method of manufacturing the electro-optical device according to the aspect of the invention, the insulating film forming step includes a film forming step of forming the insulating film, and patterning so as to partially dig up the formed insulating film. This includes a digging step of providing the digging lower portion.

  According to this aspect, the insulating film is first formed in the film forming process and then patterned so as to be partially dug in the digging process. As a result, the insulating film is provided with a digging portion having a side wall that stands up at a predetermined angle with respect to the surface of the substrate. It should be noted that a process for planarizing the surface of the insulating film is typically performed between the film forming process and the digging process.

  As described above, if the insulating film is formed by the film forming process and the digging process, the digging lower part can be provided relatively easily and reliably. Therefore, it is possible to reliably improve the coverage of the alignment film with respect to the pixel electrode while preventing the manufacturing process from becoming highly complicated.

  In the aspect in which the insulating film forming process includes a film forming process and a digging process, the digging process may be configured to include dry etching.

  In this case, since the digging process includes dry etching, etching can be performed with higher accuracy than when patterning is performed by wet etching, for example, and it is easy to provide a digging lower portion having a desired shape side wall. Become. In particular, when the layout space is narrow due to downsizing of the device, the above-described effects are remarkably exhibited. In addition to dry etching, another patterning method may be used to provide the digging lower portion. If a plurality of patterning methods are used, the side walls can be formed more suitably while taking advantage of the dry etching described above.

  Alternatively, in an aspect in which the insulating film forming step includes a film forming step and a digging step, the digging step may include wet etching.

  In this case, since the digging process includes wet etching, a stopper film for preventing excessive etching is not required as compared with the case where patterning is performed by dry etching, for example, so that the apparatus configuration can be prevented from becoming complicated. It is also effective when the side wall is desired to be relatively gentle.

  In addition to wet etching, the sidewall may be formed using dry etching or other patterning methods. If a plurality of patterning methods are used, it is possible to form the sidewalls more suitably while taking advantage of the wet etching described above.

  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.

<Electro-optical device>
The electro-optical device according to this embodiment will be described with reference to FIGS. In the following embodiments, a drive circuit built-in TFT (Thin Film Transistor) active matrix drive type liquid crystal device, which is an example of the electro-optical device of the present invention, is taken as an example.

<First Embodiment>
First, the overall configuration of the electro-optical device according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view showing the overall configuration of the electro-optical device according to this embodiment, and FIG. 2 is a cross-sectional view taken along the line HH ′ of FIG.

  1 and 2, in the electro-optical device according to the present embodiment, a TFT array substrate 10 and a counter substrate 20 are disposed to face each other. The TFT array substrate 10 is an example of the “substrate” in the present invention, and is, for example, a transparent substrate such as a quartz substrate or a glass substrate, a silicon substrate, or the like. The counter substrate 20 is a transparent substrate such as a quartz substrate or a glass substrate. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20. 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. The TFT array substrate 10 and the counter substrate 20 are bonded to each other by a sealing material 52 provided in a sealing region located around the image display region 10a provided with a plurality of pixel electrodes.

  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. In the sealing material 52, a gap material such as glass fiber or glass bead is dispersed for setting the distance between the TFT array substrate 10 and the counter substrate 20 (that is, the inter-substrate gap) to a predetermined value. Note that the gap material may be arranged in the image display region 10a or a peripheral region located around the image display region 10a in addition to or instead of the material mixed in the seal material 52.

  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. A part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10 a in this way, a plurality of the pixel lines are covered along the remaining side of the TFT array substrate 10 and covered with the frame light shielding film 53. Wiring 105 is provided.

  In regions facing the four corners of the counter substrate 20 on the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are disposed. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

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

  The pixel electrode 9 a is formed in the image display area 10 a on the TFT array substrate 10 so as to face the counter electrode 21. On the surface of the TFT array substrate 10 facing the liquid crystal layer 50, that is, on the pixel electrode 9a, an alignment film 16 is formed so as to cover the pixel electrode 9a. The configuration unique to the pixel electrode 9a according to this embodiment will be described in detail later.

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

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

  In addition to the above-described drive circuits such as the data line drive circuit 101 and the scanning line drive circuit 104, the image signal on the image signal line is sampled on the TFT array substrate 10 shown in FIGS. Sampling circuit that supplies lines, precharge circuit that supplies pre-charge signals of a predetermined voltage level to multiple data lines in advance of image signals, inspection of quality, defects, etc. of the electro-optical device during production or shipment An inspection circuit or the like may be formed.

  Next, an electrical configuration of the pixel portion of the electro-optical 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 electro-optical device according to this embodiment.

  In FIG. 3, a pixel electrode 9a and a TFT 30 are formed in each of a plurality of pixels formed in a matrix that forms the image display region 10a. The TFT 30 is electrically connected to the pixel electrode 9a, and performs switching control of the pixel electrode 9a during the operation of the electro-optical device according to the present embodiment. 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 to be 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. May be.

  The scanning line 3a is electrically connected to the gate of the TFT 30, and the electro-optical device according to the present embodiment pulse-scans the scanning signals G1, G2,. Gm is applied in this order in a line sequential manner. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,... Supplied from the data line 6a is closed by closing the switch of the TFT 30 serving as a switching element for a certain period. Sn is written at a predetermined timing. A predetermined level of image signals S1, S2,..., Sn written in the liquid crystal as an example of the electro-optical material via the pixel electrode 9a is held for a certain period with the counter electrode formed on the counter substrate. The

  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. For example, in the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel. In the normally black mode, the transmittance is applied in units of each pixel. As a result, the transmittance for incident light is increased, and light having a contrast corresponding to an image signal is emitted from the electro-optical device as a whole.

  In order to prevent the image signal held here from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode 21 (see FIG. 2). The storage capacitor 70 is a capacitive element that functions as a storage capacitor that temporarily holds the potential of each pixel electrode 9a in response to supply of an image signal. One electrode of the storage capacitor 70 is electrically connected to the drain of the TFT 30 in parallel with the pixel electrode 9a, and the other electrode is electrically connected to the capacitor line 300 having a fixed potential so as to have a constant potential. ing. 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.

  Next, a specific configuration of the pixel portion that realizes the above-described operation will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a specific configuration of the pixel portion in the electro-optical device according to this 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. In FIG. 4, for convenience of explanation, illustration of a portion located above the pixel electrode 9a is omitted.

  In FIG. 4, on the lower TFT array substrate 10, a lower light-shielding film 11a made of, for example, tungsten (W), titanium (Ti), titanium nitride (TiN), or the like is formed. The lower light-shielding film 11a is, for example, light that travels to the TFT 30 among return light, such as back-surface reflection on the TFT array substrate 10 or light that is emitted from another liquid crystal device by a multi-plate projector or the like and penetrates the composite optical system. Shield from light.

  On the lower light shielding film 11a, a base insulating film 12 made of, for example, a silicon oxide film is formed. The underlying insulating film 12 is formed on the entire surface of the TFT array substrate 10, thereby preventing a change in characteristics of the pixel switching TFT 30 due to roughness during polishing of the surface of the TFT array substrate 10 or dirt remaining after cleaning. Have.

  The TFT 30 includes a semiconductor layer 1a, a gate insulating film 2, and a gate electrode 3b.

  The semiconductor layer 1a includes, 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 / drain region 1e. . That is, the TFT 30 has an LDD structure. The TFT 30 may have an offset structure in which no impurity is implanted into the data line side LDD region 1b and the pixel electrode side LDD region 1c. Alternatively, the TFT 30 may be implanted with a high concentration of impurities using the gate electrode as a mask. A self-aligned type in which the region and the pixel electrode side source / drain region are formed may be used.

  The gate electrode 3b is made of, for example, conductive polysilicon and is electrically connected to the scanning line 3a (see FIG. 3). The gate electrode 3b is disposed above the semiconductor layer 1a via an insulating film 202 made of a silicon oxide film or the like. Further, the portion of the semiconductor layer 1a facing the channel region 1a 'is disposed via the gate insulating film 2.

  A storage capacitor 70 is provided on the upper layer side of the TFT 30 on the TFT array substrate 10 via the first interlayer insulating film 41. The storage capacitor 70 is formed by disposing the lower capacitor electrode 71 and the upper capacitor electrode 300 to face each other with the dielectric film 75 interposed therebetween.

  The upper capacitor electrode is formed as a part of the capacitor line 300. Although not shown in the figure, the capacitor line 300 extends from the image display region 10a in which the pixel electrode 9a is disposed to the periphery thereof and is electrically connected to a constant potential source. Thus, the upper capacitor electrode 300 is maintained at a fixed potential and can function as a fixed potential side capacitor electrode. The upper capacitor electrode 300 is formed of a non-transparent metal film containing a metal or alloy such as Al (aluminum) or Ag (silver), for example, and functions as an upper light-shielding film (built-in light-shielding film) that shields the TFT 30. To do. The upper capacitor electrode 300 is made of, for example, a refractory metal such as Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), Pd (palladium), or the like. You may be comprised from the alloy, metal silicide, polysilicide, etc. which contain at least one.

  The lower capacitor electrode 71 is a pixel potential side capacitor electrode electrically connected to the pixel electrode side source / drain region 1e of the TFT 30 and the pixel electrode 9a. More specifically, the lower capacitor electrode 71 is electrically connected to the pixel electrode side source / drain region 1e through the contact hole 83, and is also electrically connected to a relay layer (not shown). The lower capacitor electrode 71 is made of, for example, conductive polysilicon, or a non-transparent metal film containing a metal or an alloy such as Al (aluminum).

  The dielectric film 75 has a single layer structure or a multilayer structure composed of a silicon oxide film such as an HTO (High Temperature Oxide) film, an LTO (Low Temperature Oxide) film, or a silicon nitride film.

  A data line 6 a is provided on the upper layer side of the storage capacitor 70 on the TFT array substrate 10 via the second interlayer insulating film 42. The data line 6a is electrically connected to the data line side source / drain region 1d of the semiconductor layer 1a through a contact hole 81 penetrating the insulating film 202, the first interlayer insulating film 41, the dielectric film 75, and the second interlayer insulating film. Connected.

  A pixel electrode 9a is formed above the data line 6a via the third interlayer insulating film 43 and the fourth interlayer insulating film 210. The pixel electrode 9a is electrically connected to the pixel electrode side source / drain region 1e of the semiconductor layer 1a via a relay layer (not shown), the lower capacitor electrode 71, the contact hole 83, and the like. In the present embodiment, in particular, since the fourth interlayer insulating film 210 is provided with a dug portion, the pixel electrode 9a is tapered. That is, the fourth interlayer insulating film 210 is an example of the “insulating film” in the present invention.

  Next, detailed configurations of the fourth interlayer insulating film 210 and the pixel electrode 9a described above will be described with reference to FIGS. FIG. 5 is an enlarged cross-sectional view showing the configuration of the fourth interlayer insulating film and the pixel electrode according to the first embodiment, and FIG. 6 shows the configuration of the fourth interlayer insulating film and the pixel electrode according to the comparative example. It is an expanded sectional view.

  In FIG. 5, the fourth interlayer insulating film 210 is provided with a dug lower portion 215 having side walls 215a and 215b that overlap with the end portion of the pixel electrode 9a when viewed in plan on the TFT array substrate 10. The dug portion 215 is formed by subjecting the fourth interlayer insulating film 210 to a patterning process such as dry etching. By providing the digging portion 215 in the fourth interlayer insulating film 210, the pixel electrode 9a in the upper layer of the fourth interlayer insulating film 210 is formed so that the end portion is inclined along the side walls 215a and 215b. That is, the end portion is formed so as to fall into the dug portion 215. Thereby, the pixel electrode 9a is tapered.

  On the upper surface of the pixel electrode 9a, an alignment film 16 subjected to a predetermined alignment process such as a rubbing process is formed. Particularly in this embodiment, since the pixel electrode 9a is tapered, the coverage of the alignment film 16 can be effectively increased. That is, since the alignment film 16 can be formed along a relatively gentle slope in the pixel electrode 9a, it is possible to prevent the alignment film 16 from being deteriorated.

  In FIG. 6, if the fourth interlayer insulating film 210 is not provided with the digging portion 215, the end portion of the pixel electrode 9a is not tapered as shown in the drawing. When the alignment film 16 is provided on such a pixel electrode 9a, the end portion of the pixel electrode 9a has a relatively sharp shape. Such a gap occurs. Then, the alignment regulation force with respect to the liquid crystal molecules in the liquid crystal layer 50 (see FIG. 2) by the alignment film 16 is weakened, which may cause alignment failure. For example, the poor alignment causes a reduction in the quality of the image displayed in the image display area 10a (see FIG. 1).

  On the other hand, in the electro-optical device according to this embodiment shown in FIG. 5, as described above, since the lower interlayer 215 is provided in the fourth interlayer insulating film 210, the coverage of the alignment film 16 is increased. Can do. Therefore, alignment failure of liquid crystal molecules in the liquid crystal layer 50 can be prevented. Such an effect is remarkably exhibited when the distance between the pixel electrodes 9a becomes narrow due to downsizing and high definition of the device.

  As described above, according to the electro-optical device according to the first embodiment, since the coverage of the alignment film 16 with respect to the pixel electrode 9a can be improved, a high-quality image can be displayed.

<Second Embodiment>
Next, an electro-optical device according to a second embodiment will be described with reference to FIG. FIG. 7 is an enlarged sectional view showing the configuration of the fourth interlayer insulating film and the pixel electrode according to the second embodiment. The second embodiment differs from the first embodiment described above in that it includes a fifth interlayer insulating film, and the other configurations are generally the same. Therefore, in the second embodiment, portions different from the first embodiment will be described in detail, and descriptions of other overlapping portions will be omitted as appropriate.

  In FIG. 7, in the electro-optical device according to the second embodiment, a fifth interlayer insulating film 210 is formed between the fourth interlayer insulating film 210 and the pixel electrode 9a. In this case, the fifth interlayer insulating film 220 on the fourth interlayer insulating film 210 is formed to have an inclined surface due to the step of the dug portion 215. Therefore, the pixel electrode 9 a on the fifth interlayer insulating film 220 is also in a state where the end is inclined along the inclined surface of the fifth interlayer insulating film 220. That is, even when another insulating film is formed between the fourth interlayer insulating film 210 and the pixel electrode 9a, the pixel electrode 9a can be tapered. Therefore, the coverage of the alignment film 16 can be increased.

  It is possible to form a plurality of other insulating films between the fourth interlayer insulating film 210 and the pixel electrode 9a. However, as the number of other insulating films increases, the inclination angle of the end portion of the pixel electrode 9a is increased. Becomes smaller. Therefore, it is desirable that the number of other insulating films provided between the fourth interlayer insulating film 210 and the pixel electrode 9a should not form two or more insulating films. However, for example, when it is desired to make the inclination of the pixel electrode gentle, the inclination of the pixel electrode 9a can be adjusted by forming another insulating film between the fourth interlayer insulating film 210 and the pixel electrode 9a. .

  It is also possible to provide a digging portion in another insulating film provided between the fourth interlayer insulating film 210 and the pixel electrode 9a. In this case, the inclination of the pixel electrode 9a can be adjusted by the digging portion 215 in the fourth interlayer insulating film 210 and the digging portion in the other insulating film.

  As described above, according to the electro-optical device according to the second embodiment, since the coverage of the alignment film 16 with respect to the pixel electrode 9a can be improved as in the first embodiment described above, a high-quality image is obtained. Can be displayed.

<Method of manufacturing electro-optical device>
Next, a method for manufacturing the electro-optical device according to this embodiment will be described with reference to FIGS. 8 to 11 are process cross-sectional views sequentially showing the method of manufacturing the electro-optical device according to this embodiment. In the following, a case where the electro-optical device shown in FIG. 5 is manufactured will be described as an example. For convenience of explanation, explanation of the manufacturing process on the lower layer side from the fourth interlayer insulating film is omitted.

  8, in the method of manufacturing the electro-optical device according to the present embodiment, first, a fourth interlayer insulating film 210 is formed on the third interlayer insulating film 43 (see FIG. 4), and for example, CMP (Chemical Mechanical Polishing) or the like. The planarization process is performed by this polishing technique.

  In FIG. 9, the formed fourth interlayer insulating film 210 is subjected to a patterning process by dry etching, whereby a digging lower portion 215 having side walls 215a and 215b is provided. That is, the fourth interlayer insulating film 210 is partially dug to provide the dug lower portion 215. The depth and width of the dug portion 215 are determined based on, for example, the thickness and interval of the pixel electrodes 9a. In the patterning process described above, wet etching may be used in addition to dry etching.

  In FIG. 10, an ITO film 9b for forming the pixel electrode 9a (see FIG. 4) is formed on the fourth interlayer insulating film 210 provided with the digging portion 215. The ITO film 9b is formed so as to cover the entire fourth interlayer insulating film 210. At this time, the ITO film 9b is formed so as to be locally recessed along the side walls 215a and 215b in the digging portion 215.

  In FIG. 11, the formed ITO film 9 b is subjected to a patterning process such as dry etching on a portion provided in the dug lower part 215. That is, unnecessary portions in the ITO film 9b are removed and formed as a plurality of pixel electrodes 9a. In other words, the dug lower part 215 is provided so as to divide each pixel, and by removing the ITO film 9b provided in the dug lower part 215, a plurality of pixel electrodes 9a are formed. Here, in particular, since the pixel electrode 9b is provided so that the end thereof is along the side walls 215a and 215b in the dug portion 215, the pixel electrode 9a is in a tapered state.

  Returning to FIG. 5, an alignment film 16 made of an organic film such as a polyimide film and subjected to a predetermined alignment process such as a rubbing process is formed on the pixel electrode 9a. In the present embodiment, the pixel electrode 9a is tapered, so that the coverage of the alignment film 16 can be effectively increased. That is, since the alignment film 16 can be formed along a relatively gentle slope in the pixel electrode 9a, it is possible to prevent the alignment film 16 from being deteriorated. Therefore, the alignment defect of the liquid crystal molecules in the liquid crystal layer 50 (see FIG. 2) can be effectively prevented. Therefore, it is possible to manufacture an electro-optical device that can display a high-quality image.

  When the electro-optical device as shown in FIG. 7 is manufactured, the fifth interlayer insulating film 220 is formed after the fourth interlayer insulating film 210 is provided with the digging portion. Then, the ITO film 9b is formed on the fifth interlayer insulating film 220, and the pixel electrode 9a is formed. In this case, since the fifth interlayer insulating film 220 is formed along the digging portion 215, the pixel electrode 9a formed on the upper layer of the fifth interlayer insulating film 220 is tapered. Note that a patterning process such as etching may be performed on a portion of the fifth interlayer insulating film 220 that overlaps with the dug lower portion 215. That is, the fourth lower interlayer insulating film 210 and the fifth lower interlayer insulating film 220 may be configured such that the dug portions 215 overlap with each other.

  Next, a modification of the electro-optical device manufacturing method according to the present embodiment will be described with reference to FIGS. FIG. 12 is a process cross-sectional view illustrating a modified example of the method of manufacturing the electro-optical device according to the embodiment. FIGS. 13 and 14 are diagrams illustrating the electric device manufactured by the method of manufacturing the electro-optical device shown in FIG. It is sectional drawing which shows the structure of an optical apparatus.

  In FIG. 12, the deposited fourth interlayer insulating film 210 shown in FIG. 9 is subjected to patterning processing by wet etching, so that a dug lower portion 215 having relatively gentle side walls 215a and 215b is provided. Also good. That is, the side walls 215a and 215b in the dug portion 215 do not have to have an angle close to a right angle with respect to the substrate surface as shown in FIG.

  In FIG. 13, even when the dug portion 215 is provided by wet etching, the pixel electrode 9 a can be tapered by manufacturing in the same manner as in the above-described embodiment. In this case, the edge angle of the pixel electrode 9a is gentler than that of the pixel electrode 9a shown in FIG. 11 and the like, but the coverage of the alignment film 16 can be improved in the same manner. Further, as shown in FIG. 14, even when the fifth interlayer insulating film 220 is provided, the coverage of the alignment film 16 can be improved.

  The coverage of the alignment film 16 varies depending on various conditions such as the material and thickness of the alignment film 16 and the pixel electrode 9a. Therefore, if the patterning method of the dug lower part 215 is changed according to these conditions, the coverage of the alignment film 16 can be improved more effectively. That is, by changing the patterning method, the taper angle at the end of the pixel electrode 9a can be adjusted, so that the coverage of the alignment film 16 can be effectively improved.

  As described above, according to the method for manufacturing an electro-optical device according to this embodiment, it is possible to preferably manufacture an electro-optical device that can display a high-quality image.

<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. 15 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. 15, a projector 1100 includes a lamp unit 1102 made up 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. 15, 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 embodiments, 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 and a method for manufacturing the electro-optical device are also included in the technical scope of the present invention.

1 is a plan view showing an overall configuration of an electro-optical device according to a first embodiment. It is the HH 'sectional view taken on the line of FIG. FIG. 3 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 electro-optical device according to the first embodiment. FIG. 3 is a cross-sectional view illustrating a specific configuration of a pixel unit in the electro-optical device according to the first embodiment. It is an expanded sectional view showing the composition of the 4th interlayer insulation film and pixel electrode concerning a 1st embodiment. It is an expanded sectional view showing the composition of the 4th interlayer insulation film and pixel electrode concerning a comparative example. It is an expanded sectional view showing the composition of the 4th interlayer insulation film and pixel electrode concerning a 2nd embodiment. FIG. 6 is a process cross-sectional view (part 1) illustrating the method of manufacturing the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 2) illustrating the method of manufacturing the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 3) illustrating the method of manufacturing the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view (part 4) illustrating the method of manufacturing the electro-optical device according to the embodiment in order. FIG. 10 is a process cross-sectional view illustrating a modified example of the method for manufacturing the electro-optical device according to the embodiment. FIG. 13 is a cross-sectional view (part 1) illustrating the configuration of the electro-optical device manufactured by the method of manufacturing the electro-optical device illustrated in FIG. 12. FIG. 13 is a cross-sectional view (part 2) illustrating the configuration of the electro-optical device manufactured by the method of manufacturing the electro-optical device illustrated in FIG. 12. 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, 3a ... Scan line, 3b ... Gate electrode, 6a ... Data line, 9a ... Pixel electrode, 9b ... ITO film | membrane, 10 ... TFT array substrate, 10a ... Image display area, 11a ... Lower side light shielding film, 16 ... Alignment film, 20 ... Counter substrate, 30 ... TFT, 41 ... First interlayer insulation film, 42 ... Second interlayer insulation film, 43 ... Third interlayer insulation film, 50 ... Liquid crystal layer, 70 ... Storage capacitor, 101 ... Data Line drive circuit 102 ... External circuit connection terminal 104 ... Scanning line drive circuit 210 ... Fourth interlayer insulating film 215 ... Lower digging portion 215a, 215b ... Side wall 220 ... Fifth interlayer insulating film

Claims (8)

A substrate,
An insulating film provided on the substrate and provided with a digging lower portion having a side wall that stands up at a predetermined angle with respect to the surface of the substrate;
A plurality of pixel electrodes formed on an upper layer side of the insulating film, and having end portions inclined by being provided so as to at least partially overlap the side wall when viewed in plan on the substrate;
An electro-optical device comprising: an alignment film formed on the plurality of pixel electrodes.   The electro-optical device according to claim 1, wherein the plurality of pixel electrodes are formed immediately above the insulating film.   The electro-optical device according to claim 1, wherein end portions of the plurality of pixel electrodes are formed to have a convex curved surface on an upper layer side.   An electronic apparatus comprising the electro-optical device according to claim 1. On the board
An insulating film forming step of forming an insulating film provided with a dug lower portion having sidewalls that are cut at a predetermined angle with respect to the surface of the substrate;
A pixel electrode forming step of forming a plurality of pixel electrodes having end portions inclined by being provided on the upper layer side of the insulating film so as to at least partially overlap the side wall when viewed in plan on the substrate When,
And an alignment film forming step of forming an alignment film on the plurality of pixel electrodes. The insulating film forming step includes
A film forming step of forming the insulating film;
The method of manufacturing an electro-optical device according to claim 5, further comprising: a digging step of providing the digging lower portion by patterning the deposited insulating film so as to partially dig.   The method of manufacturing an electro-optical device according to claim 6, wherein the digging step includes dry etching.   The method of manufacturing an electro-optical device according to claim 6, wherein the digging step includes wet etching.

Images