JP2007041186A - Electrooptical device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device in which a shape desired to be heat-deformed and a shape not desired to be heat-deformed can be individually heat-deformed when individually forming required shapes at different positions on a resin film by common exposure, development, and baking. <P>SOLUTION: The liquid crystal device includes: a liquid crystal layer 12; a photopolymer film 22a with glass translation temperature G1; and a photopolymer film 22b which is formed on the photopolymer film 22a and whose glass translation temperature G2 is lower than the glass translation temperature G1. By applying exposure treatment and baking treatment, required shapes are formed accurately on the photopolymer film 22a and the photopolymer film 22b respectively. Required shapes are, for example, an irregular pattern for scattering reflection light, a contact hole 25, a recessed part 27 for adjusting the thickness of the liquid crystal layer 12. The irregular pattern on the polymer film 22b is planarized to a comparatively great extent to reduce planarization of the contact hole 25 in the polymer film 22a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electro-optical device such as a liquid crystal device, an EL (Electro Luminescence) device, a plasma display device, or the like. The present invention also relates to a manufacturing method for manufacturing the electro-optical device.

  In general, an electro-optical device such as a liquid crystal device has a substrate, and various resin films are provided on the substrate. Various shapes are formed inside the liquid crystal device by these various resin films. For example, when a liquid crystal device is considered as an electro-optical device, when a reflective display is performed by the liquid crystal device, in order to prevent specular reflection from occurring in the light reflecting film, the surface of the resin film below the light reflecting film is formed. An uneven pattern may be provided as a necessary shape.

  Further, in order to electrically connect the conductive film disposed on the upper surface of the interlayer insulating film and the other conductive film disposed on the lower surface of the interlayer insulating film, a through hole is provided at an appropriate position of the interlayer insulating film. Contact holes may be provided as necessary shapes.

  Further, when a liquid crystal device is considered as an electro-optical device, the liquid crystal device generally has a pair of substrates and a liquid crystal layer as a layer of an electro-optical material disposed between the substrates. In a dot matrix type liquid crystal device, a plurality of sub-pixels, which are the minimum unit of display, are arranged in a matrix on a plane to form a display area, and images such as characters, numbers, figures, etc. are formed in the display area. Is formed. In a so-called transflective liquid crystal device, two areas of a reflective display area and a transmissive display area are provided in a sub-pixel which is a minimum unit of display.

  The reflective display area is an area formed by providing a light reflecting film in a partial area in the sub-pixel. In the case of performing reflective display, external light such as sunlight and room light is reflected inside the liquid crystal device by the light reflection film, and display is performed using the reflected light. In addition, the transmissive display area is an area formed by allowing light transmission in a partial area in the sub-pixel without providing a light reflection film. In the case of performing transmissive display, light supplied from an illumination device such as a backlight is transmitted through the transmissive display region, and display is performed using the transmitted light.

  In a liquid crystal device in which a reflective display region and a transmissive display region are provided in a subpixel, the thickness of the liquid crystal layer corresponding to the reflective display region may be different from the thickness of the liquid crystal layer corresponding to the transmissive display region. Specifically, the thickness of the liquid crystal layer corresponding to the reflective display region may be made thinner than the thickness of the liquid crystal layer corresponding to the transmissive display region. More specifically, the thickness of the liquid crystal layer corresponding to the reflective display region may be set to ½ of the thickness of the liquid crystal layer corresponding to the transmissive display region.

  As described above, the thickness of the liquid crystal layer is made different between the reflective display region and the transmissive display region in the reflective display in which light passes through the liquid crystal layer twice in the reflective display region and in the transmissive display region. This is to obtain a clear display by making the retardation (Δn · d) of the liquid crystal layer uniform in the case of a transmissive display in which light passes only once through the liquid crystal layer.

  In the transflective liquid crystal device as described above, the liquid crystal device having a structure in which the thickness of the liquid crystal layer is different between the reflective display and the transmissive display is thick in the reflective display region and thin in the transmissive display region. By providing a resin film on a substrate, the thickness of the liquid crystal layer is often varied. In the case of this configuration, a concave portion is provided in a portion corresponding to the transmissive display region of the resin film.

  2. Description of the Related Art Conventionally, an electro-optical device is known that forms a contact hole as a necessary shape at an appropriate position of a resin film (see, for example, Patent Document 1). In the liquid crystal device disclosed in FIG. 4 of Patent Document 1, a contact hole, which is a through hole, is formed over two layers of a planarizing layer and a quarter-wave plate layer.

Japanese Patent Laid-Open No. 11-160507 (5th page, FIG. 4)

  In the liquid crystal device disclosed in Patent Document 1, a uniaxially oriented polymer liquid crystal film is used as a quarter-wave plate layer, and covers a two-layer structure of the liquid crystal film and a planarizing film that is a resin film. Although a contact hole is formed, such a two-layer structure is not a structure for forming any shape other than the contact hole around the contact hole, but the contact hole itself is a single shape. Is formed. Further, since the polymer liquid crystal film is not a resin film, it is considered that the resin film forming the contact hole is single.

  By the way, in the resin film used in the liquid crystal device, as shown in FIG. 10A, a through hole 102 that is a through hole is provided as a necessary shape at an appropriate position of the resin film 101 and the surface of the resin film 101 is provided. There is a structure in which the concavo-convex pattern 103 is provided as another necessary shape. For example, the through hole 102 is used for conducting a conductive film provided on the upper layer of the resin film 101 and a conductive film provided on the lower layer of the resin film 101. The concave / convex pattern 103 is used to give the concave / convex pattern to any film (for example, a light reflecting film) provided on the upper layer of the resin film 101.

  When a plurality of different shapes are provided on the resin film 101 as shown in FIG. 10A, in the conventional liquid crystal device, the resin film 101 is formed of a single photosensitive resin material. In this case, it is difficult to form both the uneven pattern 103 and the contact hole 102 in a desired shape. For example, considering the case where the resin film 101 is formed of a material that easily heats up, that is, a material that flows easily at a high temperature, that is, a material that is easily flattened at a high temperature, the necessary shape shown in FIG. After that, when a baking process is performed, as shown in FIG. 10B, the uneven pattern 103 is appropriately thermally sagged, that is, flattened to obtain a desired shape, but the contact hole 102 has a degree of heat sagging, that is, The degree of flattening is too large, and the contact hole 102 has an excessively large diameter at the upper end, but the lower end of the contact hole 102 is too large and the contact area becomes too small to obtain a desired contact property. appear.

  Conversely, considering the case where the resin film 101 is formed of a material that is difficult to heat, that is, a material that does not flow easily even at a high temperature, that is, a material that is difficult to flatten even at a high temperature, the shape shown in FIG. After that, when a baking process is performed, as shown in FIG. 10C, the contact hole 102 is appropriately heated, that is, flattened to obtain a desired shape and a desired contact property. The degree of thermal sag, that is, the degree of flattening is too small, and a situation where the state becomes too sharp occurs. In this case, when a light reflecting film is formed on the uneven pattern 103 and the same uneven pattern is given to the light reflecting film, the scattering characteristics of the light reflected by the light reflecting film become too wide, and the observer For this reason, the display becomes too dark.

  The present invention has been made in view of the above-mentioned problems, and when a necessary shape is individually provided at different positions of a resin film by common exposure, development, and baking, a shape to be thermally deformed and It is an object of the present invention to provide an electro-optical device and a method for manufacturing the same that can individually thermally deform a shape that is not desired to be thermally deformed.

  An electro-optical device according to the present invention includes a substrate, a layer of an electro-optical material, a first photosensitive resin film having a predetermined glass transition temperature disposed on the substrate, and the first photosensitive resin film. And a second photosensitive resin film having a glass transition temperature lower than the predetermined glass transition temperature formed on the first photosensitive resin film and the second photosensitive resin by exposure, development, and baking. Each of the resin films is provided in a predetermined shape.

  In the above configuration, the `` predetermined shape '' is not limited to a specific shape, but a concavo-convex pattern for forming scattered light provided on the surface of the resin film, a contact hole provided in the resin film, In a transflective liquid crystal device, a recess (including an opening penetrating the resin film) provided in the resin film to form a transmissive display region can be considered.

  According to the electro-optical device of the present invention having the above-described configuration, one resin film is formed by at least two layers of the first photosensitive resin film as the lower layer and the second photosensitive resin film as the upper layer, and Since the glass transition temperature of the second photosensitive resin film as the upper layer is set lower than the glass transition temperature of the first photosensitive resin film as the lower layer, the upper layer of the resin film is easily subject to heat sagging (ie, heat Therefore, it is possible to obtain a thermal deformation characteristic that the lower layer of the resin film is less likely to be heated (that is, less likely to be flattened by heat). Therefore, when a necessary shape is individually provided at different positions of the resin film by common exposure, development, and baking, the shape that is desired to be thermally deformed and the shape that is not desired to be thermally deformed can be individually thermally deformed. . For example, a shape that is largely thermally deformed by firing is obtained on the surface of the resin film, and at the same time, a shape that is not greatly thermally deformed even if fired is obtained below the resin film.

  Next, an electro-optical device according to the present invention includes an uneven pattern provided on the surface of the second photosensitive resin film, a second conductive film disposed on the surface of the second photosensitive resin film, A first conductive film disposed between the first photosensitive resin film and the substrate; and provided through the first photosensitive resin film and the second photosensitive resin film; and A contact hole for conducting the second conductive film may be provided. In this case, the predetermined shape provided by the exposure process and the baking process is the contact hole with respect to the first photosensitive resin film, and the uneven pattern with respect to the second photosensitive resin film. be able to. According to this configuration, the concavo-convex pattern on the contact hole can be shaped with an appropriate curvature flattened by heat, while the contact hole is in a sharp standing state that is not flattened by heat. It can be.

  The electro-optical device according to the present invention having a contact hole in the resin film may further include a switching element provided on the substrate. In this case, the first conductive film is the electric film. The electrode may be an electrode for applying a voltage to the optical material layer, and the second conductive film may be an electrode of the switching element. According to this configuration, it is desirable that the contact hole for conducting the switching element and the electrode is accurately formed in a desired upright shape inside the resin film, and the surface of the resin film is preferably flattened by heat. A shape (for example, an uneven pattern for creating scattered light) can be accurately formed.

  Next, in the electro-optical device according to the aspect of the invention, a reflective display region that performs display using reflected light and a transmissive display region that performs display using transmitted light are provided, and the second photosensitive resin film A concave-convex pattern is provided on the surface, and at least an insulating film that makes a layer thickness of the electro-optical material layer in the reflective display region smaller than a layer thickness of the electro-optical material layer in the transmissive display region is at least the first photosensitive film. The first photosensitive resin film is provided with a recess corresponding to the transmissive display area, and the predetermined shape formed by the exposure process and the baking process is the first photosensitive resin film. The photosensitive resin film is preferably the recess, and the second photosensitive resin film is preferably the uneven pattern.

  According to this structure, it is desirable that the resin film forming the transmissive display region is formed in an upright state without flattening the wall of the recess, and the surface of the resin film is desirably flattened by heat. (For example, an uneven pattern for creating scattered light) can be formed accurately.

  Next, it is desirable that the electro-optical device according to the present invention has a light reflecting film on the concavo-convex pattern provided on the surface of the second photosensitive resin film. According to this configuration, an appropriate uneven pattern can be imparted to the light reflecting film by the uneven pattern formed with an appropriate curvature, and thus desired scattering characteristics and directivity characteristics can be obtained with respect to the reflected light.

  Next, in the electro-optical device according to the invention, it is desirable that the film thickness of the second photosensitive resin film is smaller than the film thickness of the first photosensitive resin film. In the present invention, the second photosensitive resin film is a material having a low glass transition temperature (that is, a material that is easily melted), and the first photosensitive resin film is a material having a high glass transition temperature (that is, a material that is difficult to melt). Therefore, it is considered that the second photosensitive resin film as the upper layer easily flows into the first photosensitive resin film as the lower layer. However, if the thickness of the second photosensitive resin film is made smaller than the thickness of the first photosensitive resin film, the second photosensitive resin material flows in a large amount toward the first photosensitive resin material. Can be prevented.

  Next, the method for manufacturing an electro-optical device according to the present invention includes (1) a step of forming a first photosensitive resin material layer having a predetermined glass transition temperature on a substrate, and (2) the predetermined glass transition. Forming a second photosensitive resin material layer having a glass transition temperature lower than the temperature on the first photosensitive resin material layer; and (3) the first photosensitive resin material layer and the first photosensitive resin material layer. 2 exposing the layer of photosensitive resin material, (4) developing the exposed layer of the first photosensitive resin material and the layer of the second photosensitive resin material, and (5) by developing And a step of firing the first photosensitive resin film obtained from the first photosensitive resin material layer and the second photosensitive resin film obtained from the second photosensitive resin material layer by development. And

  According to the electro-optical device manufacturing method according to the present invention having the above-described configuration, one resin film is formed by at least two layers of the first photosensitive resin film as the lower layer and the second photosensitive resin film as the upper layer. Furthermore, since the glass transition temperature of the second photosensitive resin film that is the upper layer is set lower than the glass transition temperature of the first photosensitive resin film that is the lower layer, the upper layer of the resin film is easily subject to heat sagging (that is, It is possible to obtain a thermal deformation characteristic in one resin film that is easy to be flattened by heat, and that the lower layer of the resin film is difficult to sag (that is, difficult to flatten by heat). For this reason, it becomes possible to form a plurality of different shapes on the resin film in a desired shape with respect to any shape by one baking treatment. For example, a shape that is largely thermally deformed by firing is obtained on the surface of the resin film, and at the same time, a shape that is not greatly thermally deformed even if fired is obtained below the resin film.

  Next, in the electro-optical device manufacturing method according to the present invention, in the step of exposing the first photosensitive resin material layer and the second photosensitive resin material layer, the second photosensitive resin material layer It is desirable to form an exposure image having an uneven pattern on the surface. According to this configuration, the shape (for example, the contact hole) provided between the first photosensitive resin film and the second photosensitive resin film is accurately formed without being flattened, and then the second photosensitive resin film is formed. An uneven pattern (that is, a shape that becomes a desired shape by being appropriately flattened) can be accurately formed in a desired shape on the surface.

  Next, in the method for manufacturing the electro-optical device according to the invention, it is preferable that the baking step is performed at a temperature higher than a glass transition temperature of the second photosensitive resin material. If it carries out like this, the layer of 2nd photosensitive resin material can be planarized moderately, and a desired shape can be obtained.

  Next, the manufacturing method of the electro-optical device according to the present invention includes (1) a second conductive film disposed on the second photosensitive resin film, and (2) the first photosensitive resin film and the substrate. A first conductive film disposed between the first conductive resin film and (3) the first conductive resin film and the second photosensitive resin film, and the first conductive film and the second conductive film, And (4) in the step of exposing the first photosensitive resin material layer and the second photosensitive resin material layer, in the manufacturing method of manufacturing an electro-optical device having a contact hole for conducting the contact hole, It is desirable to form an exposure image of

  According to this configuration, the contact hole is accurately formed in the resin film in a solid upright state, and the upper part of the resin film or the surface thereof should be greatly flattened by heat (for example, , An uneven pattern) can be formed.

  Next, the method for manufacturing an electro-optical device according to the present invention includes a reflective display region that performs display using reflected light, a transmissive display region that performs display using transmitted light, and the second photosensitive region within the reflective region. An uneven pattern provided on the surface of the photosensitive resin film, and the electro-optical material in the transmissive display area provided between the first photosensitive resin film and the second photosensitive resin film in the transmissive display area. In the manufacturing method of manufacturing an electro-optical device having a recess for increasing the thickness of the layer, the step of exposing the layer of the first photosensitive resin material and the layer of the second photosensitive resin material includes: It is desirable that an exposure image be formed across the first photosensitive resin film and the second photosensitive resin film.

  According to this configuration, the transmissive display region can be accurately defined by the wall of the concave portion of the resin film that is in a steep standing state without being flattened, and on top of the resin film or on the surface thereof. Can form a shape (for example, a concavo-convex pattern) that is better flattened by heat.

  Next, in the electro-optical device manufacturing method according to the present invention, it is desirable that the thickness of the second photosensitive resin material layer is thinner than the thickness of the first photosensitive resin material layer. In the present invention, the second photosensitive resin film is a material having a low glass transition temperature (that is, a material that is easily melted), and the first photosensitive resin film is a material having a high glass transition temperature (that is, a material that is difficult to melt). Therefore, it is considered that the second photosensitive resin film as the upper layer easily flows into the first photosensitive resin film as the lower layer. However, if the thickness of the second photosensitive resin film is made thinner than the thickness of the first photosensitive resin film, the second photosensitive resin material flows in a large amount toward the first photosensitive resin material. Can be prevented.

(Embodiment of electro-optical device)
Hereinafter, an electro-optical device according to the present invention will be described by taking a liquid crystal device as an embodiment thereof as an example. Of course, the present invention is not limited to this embodiment. In the following description, various structures will be exemplified using drawings, but the structures shown in these drawings may be shown with different dimensions from the actual structures in order to show the characteristic parts in an easy-to-understand manner. There is. In the present embodiment, the present invention is applied to an active matrix type liquid crystal device using a TFT (Thin Film Transistor) element which is a three-terminal switching element as a switching element.

  FIG. 1 shows a side structure of an embodiment of a liquid crystal device according to the present invention. 2A and 2B are enlarged views showing one pixel portion in the liquid crystal device of FIG. 1, in which FIG. 2A is a plan view, and FIG. 2B is a short view of subpixels according to the Z1-Z1 line of FIG. The cross-sectional structure of the hand side is shown. FIG. 3 shows a cross-sectional structure on the longitudinal side of the sub-pixel according to the Z2-Z2 line in FIG. 2A, that is, a portion indicated by an arrow Z3 in FIG.

  In FIG. 1, a liquid crystal device 1 as an electro-optical device includes a liquid crystal panel 2 that is an electro-optical panel, and a lighting device 3 attached to the liquid crystal panel 2. Regarding the liquid crystal device 1, the side on which the arrow A is drawn is the observation side, and the illumination device 3 is disposed on the opposite side to the observation side with respect to the liquid crystal panel 2 and functions as a backlight.

  The liquid crystal panel 2 includes a pair of substrates 7 and 8 that are bonded to each other by a rectangular or square and annular sealing material 6 when viewed from the direction of arrow A. The substrate 7 is an element substrate on which switching elements are formed. The substrate 8 is a color filter substrate on which a color filter is formed. The sealing material 6 forms a gap, so-called cell gap G, between the element substrate 7 and the color filter substrate 8. The sealing material 6 has a liquid crystal injection port (not shown) in a part thereof, and liquid crystal as an electro-optical material is injected between the element substrate 7 and the color filter substrate 8 through the liquid crystal injection port. The injected liquid crystal forms a liquid crystal layer 12 within the cell gap G. The liquid crystal injection port is sealed with resin after the liquid crystal injection is completed. As a method for injecting liquid crystal, a method of supplying liquid crystal droplets in a region surrounded by a continuous annular sealing material 6 having no liquid crystal injection port can be adopted in addition to the method of performing through the liquid crystal injection port as described above.

  The distance between the cell gaps G, and hence the thickness of the liquid crystal layer 12 is maintained constant by a plurality of spacers (not shown) provided in the cell gap G. The spacer can be formed by placing a plurality of spherical resin members randomly (that is, disorderly) on the surface of the element substrate 7 or the color filter substrate 8. The spacer can also be formed in a columnar shape at a predetermined position by photolithography.

  The illumination device 3 includes an LED (Light Emitting Diode) 13 as a light source and a light guide body 14. As the light source, in addition to a point light source such as an LED, a linear light source such as a cold cathode tube can be used. The light guide 14 is formed by, for example, a molding process using a light-transmitting resin as a material, the side facing the LED 13 is the light incident surface 14a, and the surface facing the liquid crystal panel 2 is the light emitting surface 14b. is there. A light reflecting layer 16 is provided on the back surface of the light guide body 14 as viewed from the observation side indicated by the arrow A, if necessary. Moreover, the light-diffusion layer 17 is provided in the light-projection surface 14b of the light guide 14 as needed.

  The element substrate 7 includes a first light-transmitting substrate 7a. The first translucent substrate 7a is formed of, for example, translucent glass or translucent plastic. A polarizing plate 18a is attached to the outer surface of the first translucent substrate 7a, for example, by sticking. If necessary, an optical element other than the polarizing plate 18a, for example, a retardation plate can be additionally provided. On the other hand, on the inner surface of the first translucent substrate 7a, source electrode lines 19 extend in the column direction Y (that is, the left-right direction on the paper surface) as shown in FIG. 3 which is an enlarged view of the portion indicated by the arrow Z3. ing. The gate electrode line 21 extends in the row direction X (that is, the direction perpendicular to the paper surface). A TFT (Thin Film Transistor) element 31, which is an active element that functions as a switching element, is connected to the source electrode line 19 and the gate electrode line 21.

  An interlayer insulating film 22 as a resin film covering them is formed on the TFD element 31, the source electrode line 19 and the gate electrode line 21, a light reflecting film 23 is formed thereon, and a pixel electrode is formed thereon. 24 is formed, and an alignment film 26a is formed thereon. This alignment film 26a is subjected to an alignment process, for example, a rubbing process, and thereby the initial alignment of liquid crystal molecules in the vicinity of the element substrate 7 is determined.

  The interlayer insulating film 22 has a laminated structure in which a second photosensitive resin film 22b is laminated on a first photosensitive resin film 22a. Each of the resin films 22a and 22b is formed by patterning, for example, a resin having translucency, photosensitivity, and insulation, such as an acrylic resin or a polyimide resin, by photolithography. The second photosensitive resin film 22b is formed of a material whose glass transition temperature is lower than the glass transition temperature of the first photosensitive resin film 22a. In other words, the second photosensitive resin film 22b is formed of a material that is more likely to be heated than the first photosensitive resin film 22a, that is, a material that flows easily at a high temperature, that is, a material that is easily flattened at a high temperature. Specifically, when the firing temperature of these resin films is 220 ° C., a resin material having a glass transition temperature of 250 ° C. is used as the first photosensitive resin film 22a, and a glass transition is used as the second photosensitive resin film. A resin material having a temperature of 210 ° C. is used. That is, the first photosensitive resin film 22a is formed of a material having a glass transition temperature higher than the baking temperature, and the second photosensitive resin 22b is formed of a material having a glass transition temperature lower than the baking temperature.

  The light reflecting film 23 is formed by patterning a light reflecting material such as Al (aluminum) or an Al alloy by a photoetching process. The pixel electrode 24 is formed by patterning a metal oxide such as ITO (Indium Tin Oxide) with a photo-etching process. The alignment film 26a is formed, for example, by applying polyimide or the like.

  A plurality of light reflecting films 23 and pixel electrodes 24 are formed in a dot matrix as viewed from the direction of arrow A on the element substrate 7 of FIG. The light reflection film 23 and the pixel electrode 24 are provided at positions where the source electrode lines 19 and the gate electrode lines 21 intersect with each other, and are connected to individual TFT elements 31.

  In FIG. 3, a contact hole 25 that is a through hole serving as an opening for electrically connecting the light reflecting film 23 and the TFT element 31 is formed in the interlayer insulating film 22. The contact hole 25 is formed at a position that does not overlap with the element body portion of the TFT element 31 in a plan view, that is, in a plan view, and a position that overlaps with the light reflection film 23.

  The TFT element 31 used in this embodiment is an amorphous silicon TFT, and this TFT element 31 is a semiconductor formed by a gate electrode 32, a gate insulating layer 33, a-Si (amorphous silicon), etc. in FIG. It has a layer 34, a source electrode 35, and a drain electrode 36. The drain electrode 36 has one end connected to the semiconductor layer 34 and the other end connected to the light reflecting film 23 and the pixel electrode 24 through the contact hole 25. The source electrode 35 is formed as a part of the source electrode line 19 extending in the direction perpendicular to the paper surface (column direction Y) in FIG. Further, the gate electrode 32 extends from the gate electrode line 21 extending in the direction perpendicular to the source electrode line 19, that is, the left-right direction (row direction X) in FIG.

  In this embodiment, by providing the interlayer insulating film 22 under the pixel electrode 24, the layer of the pixel electrode 24 and the layer of the TFT element 31 are separated into different layers. This structure makes it possible to effectively use the surface of the element substrate 7 as compared with the structure in which the pixel electrode 24 and the TFT element 31 are formed in the same layer. For example, the area of the pixel electrode 24, that is, the pixel area can be increased, and therefore, a clear display can be performed in the liquid crystal device 1.

  In FIG. 1, the color filter substrate 8 facing the element substrate 7 includes a second light-transmitting substrate 8 a that is rectangular or square when viewed from the direction of arrow A. The second translucent substrate 8a is made of, for example, translucent glass, translucent plastic, or the like. A polarizing plate 18b is attached to the outer surface of the second translucent substrate 8a by, for example, sticking. If necessary, an optical element other than the polarizing plate 18b, for example, a retardation plate may be additionally provided.

  As shown in FIG. 3, a colored film 41 is formed on the inner surface of the second light transmissive substrate 8 a, a light shielding film 42 is formed around the colored film 41, and an overcoat is formed on the colored film 41 and the light shielding film 42. A layer 43 is formed, a common electrode 44 is formed thereon, and an alignment film 26b is formed thereon. The alignment film 26b is formed, for example, by applying polyimide or the like.

  Each colored film 41 is formed in a rectangular or square dot shape when viewed from the direction of arrow A. A plurality of the colored films 41 are arranged in a matrix in the row direction X (perpendicular to the paper surface in FIG. 3) and the column direction Y (left-right direction in FIG. 3) when viewed from the direction of arrow A. The light shielding film 42 is formed in a lattice shape surrounding the colored films 41. That is, the light shielding film 42 is formed in a state in which the one extending in the row direction X as shown in FIG. 3 and the one extending in the column direction Y as shown in FIG.

  In FIG. 3, each of the colored films 41 is set to an optical characteristic that allows one of B (blue), G (green), and R (red) to pass therethrough. They are arranged in a predetermined arrangement as viewed from the direction, for example, a stripe arrangement. The stripe arrangement is an arrangement in which the same colors B, G, and R are arranged in the column direction Y, and B, G, and R are arranged alternately in the row direction X.

  The arrangement of the colored film 41 can be any arrangement other than the stripe arrangement, for example, a mosaic arrangement, a delta arrangement, or the like. Further, the optical characteristics of the colored film 41 are not limited to the three primary colors B, G, and R, but may be a characteristic that allows the three primary colors C (cyan), M (magenta), and Y (yellow) to pass. In the present embodiment, the light shielding film 42 is formed by overlapping any two of the three primary colors B, G, and R. However, the light shielding film 42 can be formed by overlapping three colors of B, G, and R, or can be formed by patterning a predetermined material by photolithography. As the predetermined material in this case, for example, a light-shielding material such as Cr (chromium) can be considered. Note that in this specification, a light shielding film formed by overlapping colored films of a plurality of colors may be referred to as an overlapping light shielding film.

  The overcoat layer 43 formed on the colored film 41 and the light shielding film 42 planarizes the surfaces of the colored film 41 and the light shielding film 42, and the common electrode 44 is formed of the overcoat layer 43 thus planarized. Formed on top. The common electrode 44 is formed by patterning a metal oxide such as ITO, for example, by a photoetching process. The alignment film 26b formed on the common electrode 44 is subjected to an alignment process, for example, a rubbing process, whereby the initial alignment of liquid crystal molecules in the vicinity of the color filter substrate 8 is determined.

  In FIG. 1, the common electrode 44 is provided on the entire surface of the color filter substrate 8. On the other hand, the plurality of pixel electrodes 24 provided on the element substrate 7 are arranged in a matrix in the row direction X and the column direction Y as seen in a plan view from the arrow A direction. These pixel electrodes 24 and the common electrode 44 provided on the color filter substrate 8 overlap each other in a dot shape when seen in a plan view from the arrow A direction. Thus, the overlapping region forms a sub-pixel D which is the minimum unit for display. Then, a plurality of sub-pixels D are arranged in a matrix in the row direction X and the column direction Y, thereby forming a rectangular or square display region V as viewed from the direction of the arrow A, and characters, Images such as numbers and figures are displayed.

  In the case of performing color display using the colored film 41 composed of the three colors B, G, and R as in the present embodiment, 3 corresponding to the three colored films 41 corresponding to the three colors B, G, and R. One subpixel D forms one pixel. On the other hand, when performing monochromatic display in black and white or any two colors, one pixel is formed by one sub-pixel D. As shown in FIG. 2A, which is a plan view showing one pixel portion, the sub-pixel D is formed in a rectangular shape.

  In FIG. 3, which is a cross-sectional view taken along line Z2-Z2 in FIG. 2A, the light reflecting film 23 is formed by, for example, a photo etching process. The light reflecting film 23 is provided in a partial region R of the sub-pixel D, and is not provided in the remaining region T. The region R is a part of the rectangular region in the sub-pixel D as shown in FIG. 2A, and the region T is the remaining rectangular region in the sub-pixel D.

  In each of the sub-pixels D, a region where the light reflecting film 23 exists is a reflective display region R, and a region T where the light reflecting film 23 does not exist is a transmissive display region. In FIG. 3, the external light L0 incident from the observation side indicated by the arrow A is reflected by the reflective display region R. On the other hand, the light L1 in FIG. 3 emitted from the light guide 14 of the illumination device 3 in FIG.

  Convex patterns are formed on the surface of the interlayer insulating film 22, specifically the surface of the second photosensitive resin film 22 b corresponding to the reflective display region R in each sub-pixel D. Is formed. This concavo-convex pattern is a random (that is, disordered) pattern as viewed from the direction of arrow A. The light reflecting film 23 is formed on the interlayer insulating film 22 on which such a concavo-convex pattern is formed, and itself has the same concavo-convex pattern. By forming the uneven pattern on the light reflection film 23 in this way, the light L0 reflected by the light reflection film 23 is not specular reflection but light with appropriate scattered light and appropriate directivity. it can.

  The interlayer insulating film 22 is provided in the reflective display region R and is not provided in the transmissive display region T. For this reason, the layer thickness t0 of the liquid crystal layer 12 in the reflective display region R is thinner than the layer thickness t1 of the liquid crystal layer 12 in the transmissive display region T. Desirably, t0 = t1 / 2. Such adjustment of the layer thickness of the liquid crystal layer 12 is performed in the case of the reflective display in which the light L0 passes through the liquid crystal layer 12 twice in the reflective display region R and the light L1 in the reflective display region T 1 in the liquid crystal layer 12. This is performed in order to obtain a clear display by making the retardation (Δnd) of the liquid crystal layer 12 uniform in the case of transmissive display that passes only once. However, “Δn” indicates the refractive index anisotropy, and “d” indicates the liquid crystal layer thickness.

  Next, in FIG. 1, the first translucent substrate 7 a constituting the element substrate 7 has an overhanging portion 46 that projects to the outside of the color filter substrate 8. A wiring 47 is formed on the surface of the overhanging portion 46 by a photo etching process or the like. A plurality of wires 47 are formed as viewed from the direction of arrow A, and the plurality of wires 47 are arranged in parallel to each other at equal intervals in the direction perpendicular to the paper surface. Further, a plurality of external connection terminals 48 are formed at the side edges of the overhanging portion 46 so as to be arranged in parallel at equal intervals in the direction perpendicular to the paper surface. For example, an FPC (Flexible Printed Circuit) substrate (not shown) is connected to the side edge of the overhanging portion 46 provided with these external connection terminals 48.

  The plurality of wirings 47 are formed so as to extend in the column direction Y toward a region surrounded by the sealing material 6. Some of these wirings 47 are directly connected to the source electrode line 19 (see FIG. 3) on the element substrate 7 and function as data lines. Further, another part of the plurality of wirings 47 is formed so as to extend in the Y direction along the side of the element substrate 7 in the region surrounded by the sealing material 6, and further bent and extends in the row direction X. It is formed as follows. These wirings 47 are directly connected to the gate electrode line 21 (see FIG. 3) on the element substrate 7 and function as scanning lines.

  A driving IC 52 is mounted on the surface of the overhanging portion 46 in FIG. 1 by COG (Chip On Glass) technology using an ACF (Anisotropic Conductive Film) 51. The driving IC 52 transmits a data signal to the source electrode line 19 and transmits a scanning signal to the gate electrode line 21. The driving IC 52 may be formed by one IC chip, or may be formed by a plurality of IC chips as necessary. When the driving IC 52 is composed of a plurality of IC chips, these IC chips are mounted side by side in the direction perpendicular to the paper surface of FIG.

  According to the liquid crystal device 1 configured as described above, in FIG. 1, when the liquid crystal device 1 is placed in a bright outdoor room or a bright indoor room, a reflective display is performed using external light such as sunlight or indoor light. Done. On the other hand, when the liquid crystal device 1 is placed outside or in a dark room, a transmissive display is performed using the lighting device 3 as a backlight.

  In the case of performing the reflective display, the external light L0 that has entered the liquid crystal panel 2 through the color filter substrate 8 from the direction of the arrow A on the observation side in FIG. Then, the light is reflected by the light reflection film 23 in the reflective display region R and supplied to the liquid crystal layer 12 again. On the other hand, when the transmissive display is performed, the light source 13 of the illumination device 3 in FIG. The light is emitted from the surface 14b as planar light. The emitted light is supplied to the liquid crystal layer 12 through a region where the light reflection film 23 does not exist in the transmissive display region T as indicated by a symbol L1 in FIG.

  While light is supplied to the liquid crystal layer 12 as described above, a predetermined distance specified by the scanning signal and the data signal is provided between the pixel electrode 24 on the element substrate 7 side and the common electrode 44 on the color filter substrate 8 side. Thus, the orientation of the liquid crystal molecules in the liquid crystal layer 12 is controlled for each sub-pixel D. As a result, the light supplied to the liquid crystal layer 12 is modulated for each sub-pixel D. When this modulated light passes through the polarizing plate 18b (see FIG. 1) on the color filter substrate 8 side, the passage is allowed or blocked for each sub-pixel D according to the polarization characteristics of the polarizing plate 18b. Images such as letters, numbers, figures and the like are displayed on the surface of the color filter substrate 8 and are visually recognized from the direction of the arrow A.

  Next, in FIG. 2B and FIG. 3, the interlayer insulating film 22 has a laminated structure in which the second photosensitive resin film 22b is laminated on the first photosensitive resin film 22a. A random uneven pattern is formed on the surface of the second photosensitive resin film 22a by photolithography. A contact hole 25 is formed in common for both the first photosensitive resin film 22a and the second photosensitive resin film 22b. In addition, a recess 27 for increasing the thickness t1 of the liquid crystal layer 12 in the transmissive display region T is formed in common with both the first photosensitive resin film 22a and the second photosensitive resin film 22b. The concave portion 27 also includes an opening having no interlayer insulating film 22.

  According to the present embodiment, the interlayer insulating film 22 that is one resin film is formed by two layers of a first photosensitive resin film 22a that is a lower layer and a second photosensitive resin film 22b that is an upper layer, Further, since the glass transition temperature of the second photosensitive resin film 22b as the upper layer is set lower than the glass transition temperature of the first photosensitive resin film 22a as the lower layer, the upper layer of the resin film 22 is easily subject to heat sagging. It is possible to obtain thermal deformation characteristics (that is, it is easy to flatten by heat) and the lower layer of the resin film 22 is difficult to be heated (that is, difficult to flatten by heat). Therefore, it is possible to form a plurality of shapes in the resin film 22 in a desired shape with respect to any shape by a single baking process. For example, on the surface of the resin film 22, a shape having an appropriate curvature, that is, a concavo-convex pattern is obtained by being appropriately thermally deformed by baking. At the same time, the shape of the contact hole 31 and the concave portion 27 for adjusting the thickness of the liquid crystal layer can be obtained in a firm standing state, even when baked at the lower portion of the resin film 22, for example.

  Next, the film thickness H2 of the second photosensitive resin film 22b is desirably thinner than the film thickness H1 of the first photosensitive resin film 22a. The second photosensitive resin film 22b is a material having a low glass transition temperature (that is, a material that is easily melted), and the first photosensitive resin film 2a is a material having a high glass transition temperature (that is, a material that is difficult to melt). It is considered that the second photosensitive resin film 33b as the upper layer easily flows into the first photosensitive resin film 22a as the lower layer. However, if the film thickness H2 of the second photosensitive resin film 22b is smaller than the film thickness H1 of the first photosensitive resin film 22a as in the present embodiment, the material of the second photosensitive resin film 22b is the same. It is possible to prevent a large amount of fluid from flowing toward the material of the first photosensitive resin film 22a.

(First Embodiment of Method for Manufacturing Electro-Optical Device)
Next, the method for manufacturing the electro-optical device according to the present invention will be described by taking as an example the case of manufacturing the liquid crystal device shown in FIGS. FIG. 4 shows an embodiment of a method for manufacturing an electro-optical device according to the present invention. Steps from Step P1 to Step P6 in FIG. 4 are steps for forming the element substrate 7 in FIG. Further, the process from process P11 to process P16 is a process of forming the color filter substrate 8 of FIG. In addition, the process from the process P21 to the process P27 is a process in which the substrates are bonded to form a liquid crystal display device as a product.

  In the present embodiment, the element substrate 7 and the color filter substrate 8 shown in FIG. 1 are not formed one by one, but the element substrate 7 is an element having an area large enough to form a plurality of element substrates 7. A plurality of elements of the element substrate 7 are simultaneously formed on the side mother translucent substrate. As for the color filter substrate 8, a plurality of elements of the color filter substrate 8 are simultaneously formed on a color filter-side mother translucent substrate having an area large enough to form a plurality of color filter substrates 8. And The element-side mother translucent substrate and the color filter-side mother translucent substrate are formed of, for example, translucent glass or translucent plastic.

  First, in step P1 of FIG. 4, the TFT elements 31 of FIGS. 2A, 2B and 3 which are switching elements are formed on the surface of the element-side mother translucent substrate by using a photoetching process or the like. In other words, the laminated structure shown in FIG. 2B is formed. At the same time, the source electrode line 19 and the gate electrode line 21 of FIG. 3 are formed in a predetermined pattern.

  Next, in step P2, the interlayer insulating film 22 of FIG. 3 as a resin film is formed on the substrate 7a as a laminated structure of the first photosensitive resin film 22a and the second photosensitive resin film 22b. At this time, the following various shapes are formed in the interlayer insulating film 22. That is, a concavo-convex pattern is formed on the surface of the interlayer insulating film 22, a contact hole 25 which is an opening or a through hole is further formed therein, and a concave portion 27 for adjusting the liquid crystal layer thickness is further formed. Details of this step will be described later.

  Next, in step P3, the light reflecting film 23 of FIG. 3 is formed into a predetermined dot shape by photoetching using Al or an Al alloy as a material. The light reflecting film 23 is formed on a part of the sub-pixel D, and the light reflecting film 23 is not formed on the remaining part. A region where the light reflecting film 23 is formed becomes a reflective display region R, and a region where the light reflecting film 23 is not formed becomes a transmissive display region T.

  Next, in process P4, the pixel electrode 24 of FIG. 3 is formed into a predetermined dot shape by photoetching using ITO as a material. At this time, the pixel electrode 24 is formed directly on the light reflecting film 23 so as to cover the light reflecting film 23. A sub-pixel D is defined based on a region where the pixel electrode 24 is formed. Note that the pixel electrode 24 and the light reflecting film 23 can also be formed of a single layer of a metal material having both conductivity and light reflectivity, for example, Al or an Al alloy. When the pixel electrode 24 is formed on the light reflecting film 23, the pixel electrode 24 is also disposed inside the contact hole 25 and connected to the drain electrode 36 of the switching element 31.

  Next, in step P5, the alignment film 26a of FIG. 4 is formed by printing, for example, polyimide. Next, in step P6, the alignment film 26a is rubbed. As described above, a plurality of elements of the element substrate 7 are formed on the element-side mother translucent substrate to form a large-area element-side mother substrate.

  Next, in the process P11 of FIG. 4, the colored film 41 of FIG. 3 is formed on the surface of the color filter side mother translucent substrate, and at the same time, the colored film 41 of each color is overlaid, thereby forming a light shielding member, that is, a black mask ( BM) 42. The light shielding member 42 is formed, for example, in a lattice pattern that fills the periphery of each display dot region D. The colored film 41 is formed in order for each color of B, G, and R. For example, a coloring material formed by dispersing pigments and dyes of respective colors in a photosensitive resin is formed in a predetermined arrangement by photolithography. Next, in process P12, the overcoat layer 43 in FIG. 4 is formed by photolithography using a photosensitive resin such as an acrylic resin or a polyimide resin as a material.

  Next, in step P13, the common electrode 44 in FIG. 3 is formed by photoetching using ITO as a material, and in step P14, the alignment film 26b in FIG. 3 is formed. Further, in step P15, rubbing processing as alignment processing is performed. I do. Thereafter, in step P16, the sealing material 6 of FIG. 1 is formed into a rectangular or square ring by printing, for example, an epoxy resin. Thus, a plurality of elements of the color filter substrate 8 are formed on the color filter side mother translucent substrate to form a large area color filter side mother substrate.

  Thereafter, in step P21 of FIG. 4, the element side mother substrate and the color filter side mother substrate are bonded together. As a result, a large-area panel structure having a structure in which the element-side mother substrate and the color filter-side mother substrate are bonded to each other with the sealant 6 in FIG.

  Next, the sealing material 6 included in the large-area panel structure formed as described above is cured by thermal curing or ultraviolet curing in Step P22, and both mother substrates are bonded to each other to bond the large substrates. Form. Next, in step P23, the panel structure is subjected to primary cutting, that is, primary break, and a medium-area panel structure including a plurality of liquid crystal panels 2 in FIG. A plurality of strip-shaped panel structures are formed. The liquid crystal injection opening provided in the sealing material 6 is exposed to the outside when the strip-shaped panel structure is formed by the primary break.

  Next, in step P24 of FIG. 4, liquid crystal is injected into each liquid crystal panel portion through the liquid crystal injection opening of the sealing material 6, and after the injection is completed, the liquid crystal injection opening is sealed with resin. . Next, in step P25, a second cutting, that is, a secondary break is performed, and the individual liquid crystal panels 2 shown in FIG. 1 are cut out from the strip-shaped panel structure.

  Next, in step P26 of FIG. 4, the driving IC 52 is mounted on the surface of the substrate overhanging portion 46 of FIG. 1, and the polarizing plates 18a and 18b of FIG. Further, in step P27, the illumination device 3 of FIG. Thereby, the liquid crystal display device 1 is completed.

(Insulating film formation process)
Hereinafter, the insulating film forming step of step P2 in FIG. 4 will be described in detail with reference to FIGS. FIG. 6A shows a state in which the TFT element 31, the source electrode line 19 and the gate electrode line 21 are formed on the substrate 7a in the element formation step P1 of FIG.

  When the insulating film forming step starts, first, the substrate 7a in FIG. 6A is cleaned with a predetermined cleaning liquid in step P31 in FIG. Next, in step P32 of FIG. 5, as shown in FIG. 6B, the first light-transmitting substrate 7a is covered with the TFT element 31, the source electrode line 19 and the gate electrode line 21 so as to cover the first electrode. A material 22a ′ of the photosensitive resin film 22a, for example, a photosensitive resin which is a positive resist is applied to a uniform thickness by spin coating. Next, a material 22b 'of the first photosensitive resin film 22b, for example, a photosensitive resin which is a positive resist, is applied on the first photosensitive resin material 22a' to a uniform thickness by spin coating.

  The film thickness H2 of the second photosensitive resin material 22b 'is made thinner than the film thickness H1 of the first photosensitive resin material 22a'. The glass transition temperature of the second photosensitive resin material 22b 'is selected to be lower than the glass transition temperature of the first photosensitive resin material 22a'. For example, if the temperature of the baking process performed in a later step is 220 ° C., the first photosensitive resin material 22a ′ is selected with a glass transition temperature of 250 ° C., and the second photosensitive resin material 22b ′ is A glass transition temperature of 210 ° C. is selected.

  Next, in Step P33, for example, pre-baking is performed at 90 ° C. for 120 seconds to remove the solvent in the photosensitive resin materials 22a ′ and 22b ′. Next, exposure processing is performed in process P34. Specifically, as shown in FIG. 6C, the element substrate 7a (having a large area before cutting) is placed at a predetermined position of an exposure apparatus, for example, a batch exposure apparatus, and further, a halftone mask, A halftone multi-tone exposure mask 56A is placed at a predetermined position facing the element substrate 7a. The halftone mask 56A is a halftone mask having four regions having different light transmittances, and more specifically, a halftone having a complete light transmission region A0, a partial light transmission region A1, and a complete light shielding region A2. It is a mask.

In the present embodiment, the exposure amount is varied according to the pattern formed on the interlayer insulating film 22. In particular,
(1) The complete light shielding region A2 is aligned with the portion of the concavo-convex pattern where the convex portion is to be formed,
(2) The partial light transmission region A1 is aligned with the portion of the concave / convex pattern where the concave portion is to be formed
(3) The complete light transmission region A0 is aligned with the portion where the contact hole 25 is to be formed. Similar to the contact hole 25, the complete light transmission region A0 is also aligned with the peripheral portion of the interlayer insulating film material 22 'corresponding to one liquid crystal panel.

The light transmittance of the complete light-shielding region A2 corresponding to the convex portion is T2, the light transmittance of the partial light-transmissive region A1 corresponding to the concave portion is T1, and the light transmittance of the complete light-transmissive region A0 corresponding to the contact hole is T0. In this embodiment,
T2 <T1 <T0
Set to. Also,
T2 = 0%, T0 = 100%
Set to. In some cases, it is not necessarily limited to T2 = 0% and T0 = 100%.

In this way, changing the light transmittance can be realized, for example, by providing materials having different light transmittances for each region. For example, the complete light transmission region A0 can be realized by placing no light shielding material on the mask substrate. The partial light transmission region A1 can be realized by placing a material that attenuates and transmits light, for example, molybdenum silicide (MoSi or MoSi ₂ ) on the mask substrate. How many light transmittances are set can be determined by the film thickness of the film placed on the mask substrate. The complete light-shielding region A2 can be realized by placing a material that does not transmit light completely, for example, laminated chrome having a two-layer structure of Cr and CrO _x (chromium oxide) on the mask substrate.

  When the photosensitive resin 22 ′, and hence the first photosensitive resin material 22a ′ and the second photosensitive resin material 22b ′, are irradiated with a certain amount of exposure light L2 through the halftone mask 56A having the above configuration, an exposure image indicated by a chain line is shown. The upper part is solubilized. Specifically, since the exposure amount is small in the portion exposed at the light transmittance T2 = 0% (region A2), an exposure image corresponding to the convex portion of the concavo-convex pattern is formed. Moreover, since the exposure amount is relatively small in the portion exposed at the intermediate light transmittance T1 (region A1), an exposure image corresponding to the concave portion of the concave-convex pattern is formed.

  Further, since the portion exposed at the light transmittance T0 = 100% (region A0) has a large exposure amount, an exposure image penetrating the film of the photosensitive resin 22 'is formed. As a result, an exposure image corresponding to the concavo-convex pattern is formed on the surface of the photosensitive resin 22 ′, and an exposure image corresponding to the contact hole 25 is formed inside the photosensitive resin 22 ′. An exposure image corresponding to the concave portion 27 for adjusting the thickness of the liquid crystal layer is formed inside, and a portion above the exposure image is solubilized.

  Next, development processing is performed in step P35 of FIG. Specifically, the substrate 7a in FIG. 6C is immersed in a developer for a predetermined time. Then, the solubilized portion of the photosensitive resin 22 ′ in FIG. 6C is removed, and as shown in FIG. 6D, a necessary region on the surface has a concavo-convex pattern, and an inner necessary region. An interlayer insulating film 22 having a contact hole 25 and a recess 27 for adjusting the liquid crystal layer thickness is formed.

  The photosensitive resin material 22 ′, which is the material of the interlayer insulating film 22, tends to pass a lot of yellow light derived from unreacted photosensitive groups due to its properties. In step P36 of FIG. 5, a process for completing the reaction by irradiating the interlayer insulating film 22 of FIG. 6D with an appropriate amount of ultraviolet rays, so-called bleach exposure is performed. Thereby, the yellowing of the interlayer insulating film 22 is suppressed and the transmittance is improved. Next, in the process P37 of FIG. 5, the substrate 7a and the interlayer insulating film 22 of FIG. Set to. The process P2 of FIG. 4 is completed by the above, and then the processes after the light reflection film process P3 described above are executed.

  In the present embodiment, the second photosensitive resin film 22b on which the concavo-convex pattern is formed is formed of a material having a low glass transition temperature. Therefore, when the baking process is performed in the baking step P37 of FIG. Therefore, the uneven pattern is deformed so as to have an appropriate curvature, and finally has a shape capable of exhibiting preferable scattering characteristics and directivity characteristics. On the other hand, the first photosensitive resin film 22a in which the contact holes 25 and the recesses 27 are formed is made of a material having a high glass transition temperature. In comparison, the degree of flattening is small, and therefore, the standing state can be maintained without the contour becoming gentle. In this way, different shapes can be accurately formed in different portions of one interlayer insulating film 22 by performing only one exposure, development, and baking processes for one interlayer insulating film 22. Can do.

(Second Embodiment of Manufacturing Method of Electro-Optical Device)
Next, another embodiment of the electro-optical device manufacturing method according to the present invention will be described. The overall steps of the manufacturing method of this embodiment are the same as those of the manufacturing method according to the first embodiment shown in FIG. FIG. 7 shows the manufacturing method by a process diagram. In the previous embodiment shown in FIG. 5, in the exposure step P34, the three-tone halftone mask 56A shown in FIG. 6C is used, so that an uneven pattern or contact is formed on the interlayer insulating film 22 shown in FIG. The holes 25 and the recesses 27 were formed by one exposure process and one development process. On the other hand, in this embodiment shown in FIG. 7, an interlayer insulating film is formed by two exposure processes and a subsequent development process without using a halftone mask. Hereinafter, a method using the double exposure will be described with reference to an example in which the interlayer insulating film 22 shown in FIG. 3 is formed. In the following description, the present embodiment will be described with a focus on differences from the previous embodiment, and description of common configurations will be omitted.

  When the insulating film forming step starts, first, in step P41 of FIG. 7, the substrate 7a of FIG. 8A, that is, the substrate 7a on which the TFT element 31, the source electrode line 19, and the gate electrode line 21 are formed is washed with a predetermined cleaning liquid. Wash with. Next, in step P42 of FIG. 7, as shown in FIG. 8B, the first light-transmitting substrate 7a is covered with the TFT element 31, the source electrode line 19, and the gate electrode line 21 so as to cover the first light-transmitting substrate 7a. A material 22a ′ of the photosensitive resin film 22a, for example, a photosensitive resin which is a positive resist is applied to a uniform thickness by spin coating. Next, a material 22b 'of the first photosensitive resin film 22b, for example, a photosensitive resin which is a positive resist, is applied on the first photosensitive resin material 22a' to a uniform thickness by spin coating.

  The film thickness H2 of the second photosensitive resin material 22b 'is made thinner than the film thickness H1 of the first photosensitive resin material 22a'. The glass transition temperature of the second photosensitive resin material 22b 'is selected to be lower than the glass transition temperature of the first photosensitive resin material 22a'. For example, if the temperature of the baking process performed in a later step is 220 ° C., the first photosensitive resin material 22a ′ is selected with a glass transition temperature of 250 ° C., and the second photosensitive resin material 22b ′ is A glass transition temperature of 210 ° C. is selected. Next, in step P43, for example, pre-baking is performed at 90 ° C. for 120 seconds to remove the solvent in the photosensitive resin 22 ′.

  Next, primary exposure processing is performed in process P44. This primary exposure process is a process for forming an exposure image of a concavo-convex pattern on the surface of the photosensitive resin 22 'in a region corresponding to the reflective display region R (see FIG. 4). Specifically, as shown in FIG. 8C, the element substrate 7a (having a large area before cutting) is placed at a predetermined position of an exposure apparatus, for example, a stepper, and the exposure mask 56B is further attached to the element substrate 7a. It is installed at a predetermined position facing the. The exposure mask 56B is a two-tone exposure mask having two regions, a complete light transmission region and a complete light shielding region.

  In the primary exposure process P44, the photosensitive resin 22 'is exposed with the exposure light L4 through the exposure mask 56B. By this exposure, the resin portion above the exposure image indicated by the broken line (that is, the exposure image of the concavo-convex pattern) is solubilized.

  Next, a secondary exposure process is performed in step P45 of FIG. The secondary exposure process is a process for forming a peripheral portion of the contact hole 25 and the interlayer insulating film 22 corresponding to one liquid crystal panel. Specifically, as shown in FIG. 9D, the element substrate 7a is set at a predetermined position of an exposure apparatus, for example, a batch exposure machine, and the exposure mask 56C is set at a predetermined position facing the element substrate 7a. The exposure mask 56C is a two-tone exposure mask having two regions, a complete light transmission region and a complete light shielding region.

  In the secondary exposure step P45, the photosensitive resin 22 'is exposed with the exposure light L5 through the exposure mask 56C. This exposure solubilizes the inside of the contact hole 25 and the concave portion 27 for adjusting the thickness of the liquid crystal layer indicated by broken lines. Further, an exposure image corresponding to the peripheral part of one interlayer liquid crystal panel of the interlayer insulating film 22 (see FIG. 2) is formed.

  Next, development processing is performed in step P46 of FIG. Specifically, the substrate 7a in FIG. 9D is immersed in a developer for a predetermined time. Then, the solubilized portion of the photosensitive resin 22 ′ in FIG. 8C and FIG. 9D is removed, and as shown in FIG. Then, an interlayer insulating film 22 having a contact hole 25 and a concave portion 27 for adjusting the thickness of the liquid crystal layer in a necessary region inside and having a peripheral region removed as shown in FIG. 2 is formed.

  Next, in step P47 of FIG. 8, so-called bleach exposure is performed by irradiating the interlayer insulating film 22 of FIG. 9E with an appropriate amount of ultraviolet rays to remove yellowing of the interlayer insulating film 22. Then, in step P48 of FIG. 7, the substrate 7a and the interlayer insulating film 22 of FIG. 9E are baked, for example, at 220 ° C. for 40 to 50 minutes to stabilize the shape and properties of the interlayer insulating film 22. Set to state. The process P2 of FIG. 4 is completed by the above, and then the processes after the light reflection film process P3 described above are executed.

  In the present embodiment, since the second photosensitive resin film 22b on which the concavo-convex pattern is formed is formed of a material having a low glass transition temperature, when the baking process is performed in the baking step P48 of FIG. Therefore, the uneven pattern is deformed so as to have an appropriate curvature, and finally has a shape capable of exhibiting preferable scattering characteristics and directivity characteristics. On the other hand, the first photosensitive resin film 22a in which the contact holes 25 and the recesses 27 are formed is made of a material having a high glass transition temperature. In comparison, the degree of flattening is small, and therefore, the standing state can be maintained without the contour becoming gentle. In this way, only one cycle of exposure, development, and baking is performed on one interlayer insulating film 22, that is, only two exposures, one development, and one baking are performed. Thus, different shapes can be accurately formed in different portions of one interlayer insulating film 22, respectively.

(Other Embodiments of Electro-Optical Device Manufacturing Method)
In the above embodiment, the liquid crystal device 1 shown in FIGS. 1 to 3 is manufactured. However, the present invention can also be applied when manufacturing other liquid crystal devices.

  In the embodiment described above, a positive photosensitive resin is used as the resin film. Instead, a negative photosensitive resin (that is, a part that receives light is solidified) is used instead. Can be used. The present invention can also be used when manufacturing an electro-optical device other than a liquid crystal device.

1 is a cross-sectional view of a liquid crystal device which is an embodiment of an electro-optical device according to the invention. 1 shows one pixel portion of the liquid crystal device of FIG. 1, (a) is a plan view, and (b) is a cross-sectional view on the short side of the pixel according to the Z1-Z1 line of (a). It is sectional drawing which shows the longitudinal cross section of a pixel according to the Z2-Z2 line | wire of Fig.2 (a). FIG. 6 is a process flow diagram illustrating an embodiment of a method for manufacturing an electro-optical device according to the invention. FIG. 5 is a process flow diagram showing main processes in the process flow diagram of FIG. 4. FIG. 6 is a structural transition diagram of a resin film corresponding to the process flow diagram of FIG. 5. FIG. 10 is a process flow diagram illustrating another embodiment of a method for manufacturing an electro-optical device according to the invention. FIG. 8 is a structural transition diagram of a resin film corresponding to the process flow diagram of FIG. 7. FIG. 9 is a structural transition diagram subsequent to FIG. 8. It is a figure for demonstrating the manufacturing method of the conventional electro-optical apparatus.

Explanation of symbols

1. 1. liquid crystal device (electro-optical device), 2. Liquid crystal panel 5. lighting device; Sealing material,
7). Element substrate, 7a. 7. a first translucent substrate; Color filter substrate,
8a. Second translucent substrate, 12. Liquid crystal layer, 13. LED, 14. Light guide,
18a, 18b. Polarizing plate, 19. 21. Source electrode line Gate electrode wire,
22. Interlayer insulating film (resin film), 22a. A first photosensitive resin film;
22b. Second photosensitive resin film, 23. Light reflection film, 24. Pixel electrodes,
25. Contact holes, 26a, 26b. Alignment film, 27. Recess for adjusting liquid crystal layer thickness,
31. TFT element, 32. Gate electrode, 33. Gate insulating layer, 34. Semiconductor layer,
35. Source electrode, 41. Colored film, 42. Light shielding film, 43. Overcoat layer,
44. Common electrode, 46. Overhang, 52. Driving IC,
56A, 56B, 56C. Exposure mask; Sub-pixels, G. Cell gap,
L0. External light, L1. Transmitted light, L2, L4, L5. Exposure light, R.I. Reflective display area,
T.A. Transparent display area, H1, H2. Film thickness; Indicated Area

Claims (12)

A substrate,
A layer of electro-optic material;
A first photosensitive resin film having a predetermined glass transition temperature disposed on the substrate;
A second photosensitive resin film having a glass transition temperature lower than the predetermined glass transition temperature formed on the first photosensitive resin film,
An electro-optical device, wherein each of the first photosensitive resin film and the second photosensitive resin film is provided in a predetermined shape by exposure processing and baking processing. The electro-optical device according to claim 1.
A concavo-convex pattern provided on the surface of the second photosensitive resin film;
A second conductive film disposed on the surface of the second photosensitive resin film;
A first conductive film disposed between the first photosensitive resin film and the substrate;
A contact hole provided through the first photosensitive resin film and the second photosensitive resin film and electrically connecting the first conductive film and the second conductive film;
The predetermined shape provided by the exposure process and the baking process is the contact hole with respect to the first photosensitive resin film, and the uneven pattern with respect to the second photosensitive resin film. apparatus. The electro-optical device according to claim 2.
A switching element provided on the substrate;
The electro-optical device, wherein the first conductive film is an electrode of the switching element, and the second conductive film is an electrode for applying a voltage to the electro-optical material layer. The electro-optical device according to claim 1.
A reflective display area for displaying using reflected light;
A transmissive display area for performing display using transmitted light, and
An uneven pattern is provided on the surface of the second photosensitive resin film,
An insulating film that makes the layer thickness of the electro-optical material layer in the reflective display region thinner than the layer thickness of the electro-optical material layer in the transmissive display region is constituted by at least the first photosensitive resin film; The first photosensitive resin film is provided with a recess corresponding to the transmissive display region, and the predetermined shape formed by the exposure process and the baking process is the recess for the first photosensitive resin film. The electro-optical device is characterized in that the second photosensitive resin film is the uneven pattern.   5. The electro-optical device according to claim 2, wherein a light reflecting film is provided on an uneven pattern provided on a surface of the second photosensitive resin film. Optical device.   6. The electro-optical device according to claim 1, wherein the film thickness of the second photosensitive resin film is smaller than the film thickness of the first photosensitive resin film. Optical device. Forming a layer of a first photosensitive resin material having a predetermined glass transition temperature on a substrate;
Forming a layer of a second photosensitive resin material having a glass transition temperature lower than the predetermined glass transition temperature on the layer of the first photosensitive resin material;
Exposing the layer of the first photosensitive resin material and the layer of the second photosensitive resin material;
Developing the exposed layer of the first photosensitive resin material and the layer of the second photosensitive resin material;
Baking the first photosensitive resin film obtained from the first photosensitive resin material layer by development and the second photosensitive resin film obtained from the second photosensitive resin material layer by development;
A method for manufacturing an electro-optical device. The method of manufacturing an electro-optical device according to claim 7.
In the step of exposing the layer of the first photosensitive resin material and the layer of the second photosensitive resin material, an exposure image of an uneven pattern is formed on the surface of the layer of the second photosensitive resin material. Manufacturing method of electro-optical device.   9. The method of manufacturing an electro-optical device according to claim 7, wherein the baking is performed at a temperature higher than a glass transition temperature of the second photosensitive resin material. Manufacturing method. A method for manufacturing an electro-optical device according to any one of claims 7 to 9,
A second conductive film disposed on the second photosensitive resin film;
A first conductive film disposed between the first photosensitive resin film and the substrate;
Manufacturing for manufacturing an electro-optical device having a contact hole provided through the first photosensitive resin film and the second photosensitive resin film and electrically connecting the first conductive film and the second conductive film In the method
An electro-optical device manufacturing method, wherein an exposure image of the contact hole is formed in the step of exposing the layer of the first photosensitive resin material and the layer of the second photosensitive resin material. A method for manufacturing an electro-optical device according to any one of claims 7 to 10,
A reflective display area for displaying using reflected light;
A transmissive display area for performing display using transmitted light;
A concavo-convex pattern provided on the surface of the second photosensitive resin film in the reflective region;
A recess that is provided across the first photosensitive resin film and the second photosensitive resin film in the transmissive display region and increases a layer thickness of the electro-optic material layer in the transmissive display region;
In a manufacturing method of manufacturing an electro-optical device having:
In the step of exposing the layer of the first photosensitive resin material and the layer of the second photosensitive resin material, an exposure image of the concave portion is formed across the first photosensitive resin film and the second photosensitive resin film. A method for manufacturing an electro-optical device. 12. The method of manufacturing an electro-optical device according to claim 7, wherein a thickness of the second photosensitive resin material layer is smaller than a thickness of the first photosensitive resin material layer. A method of manufacturing an electro-optical device.

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