JP2006039348A - Method for manufacturing substrate for electro-optical device, and method for manufacturing electro-optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a substrate for an electro-optical device and a method for manufacturing an electro-optical device which do not cause misalignment between exposure masks even when performing multiple exposure.
In a manufacturing process of an electro-optical device substrate of a liquid crystal device 100, a photosensitive resin 138 coated on a large substrate 400 is sequentially exposed with four exposure masks 210, 20, 230, and 240, and a cumulative exposure amount is obtained. Is made different for each region, thereby forming a base layer having a plurality of types of convex portions having different height dimensions. At that time, alignment marks 129 are formed in advance on the large substrate 400, and the exposure masks 210, 20, 230, and 240 are positioned.
[Selection] Figure 7

Description

  The present invention relates to a method for manufacturing a substrate for an electro-optical device and a method for manufacturing an electro-optical device.

  In a transflective electro-optical device capable of displaying an image in the reflection mode or a total reflection electro-optical device, an electro-optical device substrate having a light reflecting portion is used. Here, if the reflective surface is a flat surface, the background will be reflected on the screen. Therefore, an underlayer having irregularities is formed on the lower layer side of the reflective layer with a photosensitive material, and the reflective layer is formed on the surface thereof. Has been proposed (see, for example, Patent Document 1).

In the method disclosed in Patent Document 1, as shown in FIG. 12 (a), a positive type photosensitive resin 510 is applied on a substrate 500 and then applied as shown in FIG. 12 (b). The photosensitive resin 510 is exposed through the exposure mask 520. Of the exposure mask 520, the light-transmitting portions 530 arranged at random are for forming an uneven surface of the base layer 540a. When the photosensitive resin 510 is exposed with such an exposure mask 520 and then subjected to development processing, as shown in FIG. 12C, a base layer 540a having an uneven surface is formed. Next, as shown in FIG. 12D, after applying positive type photosensitive resin again, the mounting area around the panel display area is exposed, and then subjected to development processing, whereby a base layer 540b having an uneven surface is formed. Is formed. Therefore, when the reflective layer 560 made of aluminum or the like is formed on the surface of the base layer 540b, the unevenness of the base layers 540a and 540b is reflected on the surface, and the reflective layer 560 having a large number of convex portions having the same height dimension is formed. can do. Here, if the convex portions formed on the surface of the reflective layer 560 are regular, interference fringes are generated. Therefore, in Patent Document 1, the convex portions are randomly arranged in the plane direction.
JP 2003-75987 A

  However, even if the convex portions are randomly arranged in the plane direction as in the technique described in Patent Document 1, the arrangement pattern is limited, and thus the generation of interference fringes cannot be completely prevented. There is a point.

  Here, the inventor proposes to completely prevent the occurrence of interference fringes by forming a plurality of types of convex portions having different height dimensions and increasing the degree of freedom in designing the convex portions.

  If it is going to comprise such a convex part by the conventional technique, after developing multiple exposure to a photosensitive resin with a plurality of exposure masks which have mutually different exposure patterns to make the cumulative exposure amount for the photosensitive resin different for each region, development Then, after forming a base layer having a convex portion having a height corresponding to the difference in accumulated exposure amount, a reflective layer is formed on the surface of the base layer. However, the conventional technique has a problem that desired unevenness cannot be formed due to the positional deviation between the exposure masks.

  In view of the above problems, an object of the present invention is to provide a method for manufacturing a substrate for an electro-optical device and a method for manufacturing an electro-optical device that do not cause misalignment between exposure masks even when multiple exposure is performed. It is in.

  In order to solve the above problems, in the present invention, an alignment mark forming step for forming an alignment mark on a substrate, a coating step for applying a photosensitive material on the substrate, and a plurality of exposure masks having different exposure patterns. The multiple exposure step of sequentially exposing the photosensitive material, the developing step of developing the photosensitive material to form a base layer having convex portions having different heights, and forming a reflective layer on the base layer A reflecting layer forming step, and in the multiple exposure step, a positioning step of positioning each of the exposure masks based on the alignment mark is performed before at least the second and subsequent exposures.

  In the present invention, the alignment mark forming step is performed before the multiple exposure step, and in the multiple exposure step, the exposure mask is positioned based on the alignment mark before at least the second and subsequent exposures. Therefore, even if multiple exposure is performed, misalignment between exposure masks can be prevented, so that highly accurate exposure can be performed. Therefore, since a plurality of types of convex portions having different height dimensions can be formed at predetermined positions on the underlayer, light scattering irregularities can be formed at predetermined positions on the reflective layer surface. Therefore, with respect to the arrangement pattern of the light scattering unevenness, a parameter called a height dimension can be added in addition to the position in the plane direction, so that the generation of interference fringes can be completely prevented. In addition, it is preferable to perform positioning based on the alignment mark before all exposures in the multiple exposure process. However, if the positioning based on the alignment mark is performed at least before each subsequent exposure, the exposure masks used in the multiple exposure process Can be effectively prevented. In addition, it is possible to perform alignment with the exposure apparatus using the reference side of the substrate without using the alignment mark, but in this case, the alignment accuracy is significantly lower than when the alignment mark is used. There is a problem of end.

  In the present invention, in the alignment mark forming step, it is preferable to form a wiring pattern on the substrate simultaneously with forming the alignment mark.

  In the present invention, in the alignment mark forming step, the alignment mark is formed on the substrate using a material that develops or changes color when exposed, and the alignment mark is exposed during the first exposure in the multiple exposure step. The alignment mark may be colored or discolored. If comprised in this way, since it positions based on the position of the exposure mask in the case of the 1st exposure, the position shift of the exposure masks used in a multiple exposure process can be prevented reliably.

  In the present invention, in the multiple exposure step, for example, exposure is performed so that a partial region of the photosensitive material is removed in the developing step, and in the reflective layer forming step, the region corresponding to the removed portion is exposed. A region where no reflective layer is provided is formed.

  In the present invention, it is preferable that the plurality of exposure masks include masks having different external sizes. If comprised in this way, it can expose with the exposure mask of the size corresponding to the part to expose on a board | substrate.

  In the present invention, the plurality of exposure masks include a step exposure mask for step exposure of the substrate and a batch exposure mask for batch exposure of the substrate. In the multiple exposure step, The step of performing step exposure using the step exposure mask and the step of performing batch exposure using the batch exposure mask may be performed.

  In the present invention, the alignment mark forming step for forming an alignment mark on one of the pair of substrates sandwiching the electro-optical material, and the coating step for applying a photosensitive material on the one substrate are different exposure patterns. A multiple exposure step of sequentially exposing the photosensitive material with a plurality of exposure masks, a developing step of developing the photosensitive material to form a base layer having convex portions having different heights, and the base layer A reflective layer forming step for forming a reflective layer thereon, and in the multiple exposure step, a positioning step of positioning each of the exposure masks based on the alignment mark at least before each second and subsequent exposures It is characterized by performing.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings shown below, the dimensions and ratios of the components are appropriately different from the actual ones in order to make the components large enough to be recognized on the drawings.

[Configuration of liquid crystal device]
FIG. 1 is a cross-sectional view of a liquid crystal device (electro-optical device) according to this embodiment, and FIG. 2 is an exploded perspective view showing a schematic configuration of the liquid crystal device. 3A and 3B are each a plan view of one dot of an electro-optical device substrate used in the liquid crystal device according to the present embodiment, and an explanatory diagram schematically showing a cross section taken along the line BB ′. It is. 1 corresponds to a cross section taken along line AA ′ in FIG.

  As shown in FIGS. 1 and 2, the liquid crystal device 100 of this embodiment includes a liquid crystal 180 that holds a liquid crystal 180 (not shown in FIG. 2) as an electro-optical material between a first substrate 110 and a second substrate 120. The panel 102 and the backlight unit 104 disposed on the second substrate 120 side of the liquid crystal panel 102 are provided. In the following description, for the sake of convenience, the first substrate 110 side with respect to the liquid crystal 180 is referred to as “observation side” in the sense that the observer viewing the display image by the liquid crystal device 100 is positioned as shown in FIG. ”And the second substrate 120 side from the liquid crystal 180 is referred to as“ back side ”.

  The backlight unit 104 includes, for example, a light guide plate 106 made of a molded product of a light transmissive resin, and a light source 105 such as an LED or a cold cathode tube. The light source 105 is a light guide plate that is a plate-like member. Light is irradiated to the side end face of 106. A diffusion plate (not shown) that uniformly diffuses light from the light guide plate 106 with respect to the liquid crystal panel 102 is disposed on the surface of the light guide plate 106 that faces the liquid crystal panel 102. Further, on the opposite surface, a reflection plate (not shown) for reflecting the light to be emitted from the light guide plate 106 to the back side is arranged on the liquid crystal panel 102 side, and the light incident from the side end surface is arranged. The light is uniformly emitted toward the second substrate 120 of the liquid crystal panel 102.

  The first substrate 110 of the liquid crystal panel 102 is a plate-like member made of a light transmissive material such as glass. A phase difference plate 111 (not shown in FIG. 2) for improving contrast and a polarizing plate 112 (not shown in FIG. 2) for polarizing incident light are provided on the observation side surface of the first substrate 110. The layers are stacked in this order from the first substrate 110 side. On the surface of the first substrate 110 on the liquid crystal 180 side (back side), light transmissive pixel electrodes 114 made of an ITO (Indium Tin Oxide) film or the like are arranged in a matrix. A plurality of scanning lines 116 extending in one direction (Y direction shown in FIG. 2) are formed in the gaps between the pixel electrodes 114, and the scanning lines 116 adjacent to the pixel electrodes 114 and the pixel electrodes 14 are formed. Are connected via a TFD (Thin Film Diode) element 115 which is a two-terminal switching element having non-linear current-voltage characteristics. As shown in FIG. 1, the surface of the first substrate 110 on which the pixel electrodes 114, the scanning lines 116, and the TFD elements 115 are formed is covered with an alignment film 118 (not shown in FIG. 2). The alignment film 118 is an organic thin film such as polyimide, and is subjected to a rubbing process for defining the alignment state of the liquid crystal 180 when no voltage is applied.

  The second substrate 120 is a plate-like member made of a light transmissive material such as glass, and on the back side thereof, similarly to the first substrate 110, a retardation plate 121 (not shown in FIG. 2), and a polarizing plate 122 (not shown in FIG. 2) are stacked in this order from the second substrate 120. On the other hand, on the surface of the second substrate 120 on the liquid crystal 180 side (observation side), the underlayer 130, the reflective layer 140, the three color filters 150R, 150G, and 150B, the data line 152, and the alignment film 154 (in FIG. 2). (Not shown) are stacked in this order from the second substrate 120. Among these layers, the alignment film 154 is an organic thin film such as polyimide, like the alignment film 118, and has been subjected to a rubbing process for defining the alignment state of the liquid crystal 180 when no voltage is applied. .

  As will be described later, the underlayer 130 is formed by exposing and developing a photosensitive material, and its side end face 130a is flat. The base layer 130 is formed with an opening 135 from which the resin is completely removed near the center of the dot 160, and on the observation side (surface), a smooth uneven surface 130 b (hereinafter referred to as “uneven surface”). have.

  The reflective layer 140 is made of a light-reflective material such as aluminum or silver, for example, as shown in FIGS. 3A and 3B. The surface of the reflection layer 140 is a scattering reflection surface reflecting the uneven surface shape of the underlayer 130. Here, the reflective layer 140 includes a light transmission portion 142 from which a portion corresponding to the opening 135 of the base layer 130 is removed. Therefore, in this embodiment, the reflective layer 140 is configured as a transflective layer.

  For convenience of description, in the following description, a functional substrate including the second substrate 120, the base layer 130, and the reflective layer 140 is referred to as an “electro-optical device substrate 124”.

  The color filters 150 </ b> R, 150 </ b> G, and 150 </ b> B are resin layers provided corresponding to the dots 160. Each color filter is colored in one of red (R), green (G), and blue (B) with a pigment or the like, and selectively transmits light having a wavelength corresponding to the color. Note that “R”, “G”, and “B” in FIG. 2 indicate which color filter 150R, 150G, and 150B each dot 160 is disposed on.

  Here, a light shielding layer 151 is formed in the boundary region between the color filters 150R, 150G, and 150B. The light shielding layer 151 is, for example, a black resin material in which carbon black is dispersed, a metal material such as chromium (Cr), or the like. It is formed by. The light shielding layer 151 is not limited to be formed of a specific material. For example, the colored layers of the color filters 150R, 150G, and 150B constituting the colored layer are overlapped, that is, stacked in two colors or three colors. Can also be formed.

  Each of the plurality of data lines 152 is a strip-shaped electrode formed of a light transmissive conductive material such as ITO. As shown in FIG. 2, the data line 152 is formed on the surface of the color filters 150R, 150G, and 150B, extends in the direction (X direction in FIG. 2) intersecting the scanning line 116 described above, It is located on one substrate 110 so as to face a plurality of pixel electrodes 114 forming a column. As shown in FIG. 1, the data line 152 is located on the side end surface of the electro-optical device substrate 124 so as to straddle the side end surface, and on the second substrate 120, the data line 152 is located on the observation side surface. To do.

  As shown in FIG. 1, the first substrate 110 and the second substrate 120 having the above-described configuration are bonded together via the sealing material 170, and in a region surrounded by both the substrates and the sealing material 170, for example, TN A liquid crystal 180 such as a (Twisted Nematic) type is sealed. Under such a configuration, the liquid crystal 180 sandwiched between the first substrate 110 and the second substrate 120 is applied with a voltage between the pixel electrode 114 and the data line 152 opposed to the pixel electrode 114, thereby aligning the alignment direction thereof. Changes. As shown in FIG. 2, the minimum units 160 of the region where the alignment direction of the liquid crystal 180 changes according to the applied voltage are arranged in a matrix, and each of them functions as a sub-pixel (dot). When external light is incident on the liquid crystal panel 102 from the observation side, the external light is transmitted through the liquid crystal 180, then is scattered and reflected by the electro-optical device substrate 124, is transmitted through the liquid crystal 180 again, and is directed toward the observation side. The emitted image is displayed in the reflection mode. On the other hand, the light from the backlight unit 104 incident from the back side of the liquid crystal panel 102 passes through the opening 135 and the light transmission unit 142 and enters the liquid crystal 180 layer, and then is emitted to the observation side and is transmitted in the transmission mode. An image is displayed.

[Configuration of Electro-Optical Device Substrate 124]
As shown in FIGS. 3A and 3B, the electro-optical device substrate 124 is obtained by laminating a base layer 130 and a reflective layer 140 in this order on the surface of the second substrate 120. The surface (reflecting portion) is a scattering reflection surface reflecting the uneven surface shape of the underlayer 130. Here, the plurality of convex portions of the base layer 130 include a plurality of types of convex portions 131, 132, and 133 having different height dimensions. That is, in many convex portions of the base layer 130, the convex portion 132 is higher than the convex portion 131, and the convex portion 133 is higher than the convex portion 132. Accordingly, in the electro-optical device substrate 124, the convex portions 131, 132, and 133 are randomly arranged in the planar direction, and the convex portions 131, 132, and 133 having different heights are formed. When configured, generation of interference fringes due to reflection on the surface of the reflective layer 140 can be completely prevented.

[Method for Manufacturing Electro-Optical Device Substrate 124]
FIG. 4 is a process diagram showing a method of manufacturing the electro-optical device substrate used in the liquid crystal device shown in FIG. 5A and 5B are explanatory views of a large substrate (second substrate) used for manufacturing the substrate for the electro-optical device used in the liquid crystal device shown in FIG. 1, and an explanatory view of an exposure mask. 6, 7, and 8 are process cross-sectional views illustrating a method of manufacturing the electro-optical device substrate used in the liquid crystal device illustrated in FIG. 1.

  In manufacturing the electro-optical device substrate 124 of this embodiment, as shown in FIG. 4, an alignment mark forming process P1, a coating process P2, a drying process P3, a pre-baking process P4, a multiple exposure process P5, a developing process P6, and a baking process. P7 and the reflective layer forming step P8 are performed in this order, and in the alignment mark forming step P1, an alignment mark 129 is formed on the substrate as shown in FIG. Here, the substrate shown in FIG. 5 is a large-sized substrate 400 having a size that allows a large number of electro-optical device substrates 124 to be taken, and the alignment mark 129 is a region outside the region 410 cut out as the electro-optical device substrate 124. It is formed at a position close to each corner of 410. Note that the formation position of the alignment mark 129 is not limited to a position close to each corner of the region 410, and may be any position on the large substrate 400 as long as it can be used for positioning an exposure mask described later.

  In the present embodiment, the multiple exposure process P5 includes a plurality of exposure masks having different exposure patterns as shown in FIG. 5B, and in this embodiment, four exposure masks 210, 220, 230, and 240. The photosensitive resin is sequentially exposed to make the cumulative exposure amount for the photosensitive resin different for each region. Here, each of the four exposure masks 210, 220, 230, and 240 is a step exposure mask that performs step exposure of the large substrate 400. In the multiple exposure process P3, these exposure masks 210, 220, and 230 are used. The multiple exposure is performed on the photosensitive material by repeating the step exposure. The exposure masks 210, 220, 230, and 240 have alignment marks 219, 229, 239 for aligning with the alignment mark 129 of the large substrate 400 when the exposure masks 210, 220, 230, and 240 are arranged in predetermined regions of the large substrate 400. 249 is formed.

  Hereinafter, a method for manufacturing the electro-optical device substrate 124 according to this embodiment will be described more specifically. First, as shown in FIG. 6A, a thin film 128 such as chromium or aluminum is formed on the observation side of the second substrate 120, and then a resist mask 127 is formed on the surface of the thin film 128. Then, the thin film 128 is patterned to form alignment marks 129 on the large substrate 400 (second substrate 120) as shown in FIG. 6B (FIG. 4: process P1 / alignment mark forming step).

  Next, as shown in FIG. 6C, a positive type photosensitive resin 138, which is a kind of photosensitive material, is applied to the large substrate 400 by, for example, a spin coating method (FIG. 4: process P2 / application process). ). As the photosensitive resin 138, for example, an acrylic resin can be used.

  Next, the photosensitive resin 138 applied to the second substrate 120 is dried in a reduced pressure environment (FIG. 4: process P3), and the dried photosensitive resin 138 is pre-baked in the range of 85 ° C. to 105 ° C. (FIG. 4). : Process P4).

  Next, as shown in FIGS. 7A to 7D, the photosensitive resin 138 is subjected to multiple exposure using the exposure masks 210, 220, 230, and 240 described with reference to FIG. 4: Process P5 / Multiple exposure step). Here, the exposure masks 210, 220, 230, and 240 are formed by forming a light-shielding layer such as chrome on a light-transmitting substrate such as glass, and in this embodiment, using the light-shielding layer and the like, Alignment marks 219, 229, 239, and 249 are formed on the exposure masks 210, 220, 230, and 240.

  In the multiple exposure process P5, as shown in FIG. 7A, the stepper exposure apparatus first aligns the large substrate 400 and the first exposure mask 210 using the alignment marks 129 and 219 (positioning process). ), Exposing the photosensitive resin 138 (first exposure). Then, the entire photosensitive resin 138 formed on the large substrate 400 is step-exposed with the first exposure mask 210. Here, the first exposure mask 210 is provided with an exposure pattern including a light shielding portion 211 only in a region corresponding to the convex portion 133 described with reference to FIG. Therefore, the photosensitive resin 138 is exposed in a region corresponding to the exposure pattern of the first exposure mask 210, and in FIG. 7A, the cumulative exposure amount of the photosensitive resin 138 is indicated by a dotted line.

  Next, in the same stepper exposure apparatus, as shown in FIG. 7B, after aligning the large substrate 400 and the second exposure mask 220 using the alignment marks 129 and 229 (positioning step), the photosensitive property is obtained. Resin 138 is exposed (second exposure). Then, the entire photosensitive resin 138 formed on the large substrate 400 is step-exposed with the second exposure mask 220. Here, the second exposure mask 220 includes an exposure pattern including a light shielding portion 221 only in a region corresponding to the convex portions 132 and 133 described with reference to FIG. Therefore, the photosensitive resin 138 is exposed in a region corresponding to the exposure pattern of the second exposure mask 220, and in FIG. 7B, the cumulative exposure amount of the photosensitive resin 138 is indicated by a dotted line.

  Next, in the same stepper exposure apparatus, as shown in FIG. 7C, after aligning the large substrate 400 and the third exposure mask 230 using the alignment marks 129 and 239 (positioning step), the photosensitive property is obtained. Resin 138 is exposed (third exposure). Then, step exposure is performed on the entire photosensitive resin 138 formed on the large substrate 400 with the third exposure mask 230. Here, the third exposure mask 230 includes an exposure pattern including the light shielding portion 231 only in the region corresponding to the convex portions 131, 132, and 133 described with reference to FIG. Therefore, the photosensitive resin 138 is exposed in the area corresponding to the exposure pattern of the third exposure mask 230, and in FIG. 7C, the cumulative exposure amount of the photosensitive resin 138 is indicated by a dotted line.

  Next, in the same stepper exposure apparatus, as shown in FIG. 7D, the large substrate 400 and the fourth exposure mask 240 are aligned using the alignment marks 129 and 249 (positioning step), and then the photosensitivity. Resin 138 is exposed (fourth exposure). Then, step exposure is performed on the entire photosensitive resin 138 formed on the large substrate 400 with the fourth exposure mask 240. Here, the fourth exposure mask 240 has an exposure pattern for forming a portion where the photosensitive resin 138 is completely removed at the stage where the next development process is completed. That is, the fourth exposure mask 240 has an exposure pattern including a light shielding portion 241 in the entire area other than the area corresponding to the opening 135 described with reference to FIG. Therefore, the photosensitive resin 138 is exposed in a region corresponding to the exposure pattern of the fourth exposure mask 240, and the accumulated exposure amount of the photosensitive resin 138 is indicated by a dotted line in FIG.

  Next, the photosensitive resin 138 is developed with a predetermined developer (FIG. 4: process P6 / development step). As a result, as shown in FIG. 8A, the photosensitive resin 138 is removed according to the exposure amount, and becomes a base layer 130 on which convex portions 131, 132, and 133 having different heights are formed. In addition, an opening 135 from which the photosensitive resin 138 is completely removed is formed in the base layer 130. Next, the photosensitive resin 138 is baked (FIG. 4: process P7).

  Next, as shown in FIG. 8B, after forming a metal layer 145 such as aluminum or an aluminum alloy to be the reflective layer 140 with a substantially constant thickness so as to cover the base layer 130 by, for example, sputtering, A resist mask 260 is formed on the surface of the metal layer 145, and the metal film 145 is etched in this state. As a result, a portion of the metal layer 145 that is not covered with the resist mask 260 in the metal layer 125 is removed, and as described with reference to FIGS. 3A and 3B, the light transmission portion 142 is provided. A reflective layer 140 is formed (FIG. 4: process P8).

  In this manner, the scattering / reflection type electro-optical device substrate 124 is manufactured in the state of the large substrate 400. Thereafter, as shown in FIG. 1, a thin film made of, for example, chromium is formed on the reflecting surface side (observation side) of the second substrate 120 by, for example, sputtering, and then patterned to form a lattice-shaped light shielding layer 151. To do. The light shielding layer 151 is not limited to be formed of a specific material. For example, the colored layers of the color filters 150R, 150G, and 150B constituting the colored layer are stacked in two colors or three colors, that is, stacked. Can also be formed. Next, each of the red, green, and blue color filters 150R, 150G, and 150B is formed in a matrix on the reflective layer 140 of the second substrate 120. As a method for forming these color filters 150R, 150G, and 150B, for example, the color filters 150R, 150G, and 150B can be formed using a photosensitive resin colored with a pigment. Next, a thin film made of ITO or the like is formed so as to cover the color filters 150R, 150G, and 150B and the light shielding layer 151, and the data line 152 is formed by patterning the thin film. After that, an alignment film 154 is formed, and a rubbing process is performed on the surface of the alignment film 154. The second substrate 120 (large substrate 400) having undergone such a process and the large substrate for the first substrate on which the pixel electrode 114, the scanning line 116, the TFD element 115, and the alignment film 118 are formed are aligned with each other. 118 and 154 are bonded to each other through the sealant 170, cut to a predetermined size, and the liquid crystal 180 is injected into a space surrounded by the sealant 170 between the substrates. The space into which the liquid crystal 180 is injected is sealed with an unillustrated). As a result, a single-size liquid crystal panel 102 is completed.

(Main effects of this form)
As described above, since the large-sized substrate 400 is not formed with any thin film such as wiring at the stage before the formation of the photosensitive resin 138, the exposure masks 210, 220, 230, and 240 in the multiple exposure process P5. In the present invention, the alignment mark 129 is formed on the large substrate 400 in the alignment mark formation step P1 before performing the coating step P2 and the multiple exposure step P5. For this reason, in the multiple exposure process P5, the exposure masks 210, 220, 230, and 240 can be positioned based on the alignment marks 129 on the large substrate 129. Therefore, even if multiple exposure is performed, the exposure masks 210, 220, 230, and 240 are not misaligned with each other, so that highly accurate exposure can be performed. Accordingly, since a plurality of types of convex portions 131, 132, and 133 having different height dimensions can be formed at predetermined positions on the underlayer 130, light scattering irregularities can be formed at predetermined positions on the reflective layer 140 surface. For this reason, in the arrangement pattern of the unevenness for light scattering, in addition to the position in the plane direction, a parameter called a height dimension can be added, so that the generation of interference fringes can be completely prevented. In this embodiment, the positioning process of the exposure masks 210, 220, 230, and 240 based on the alignment mark 129 is performed before all the exposures in the multiple exposure process. If positioning based on this is performed, it is possible to effectively prevent displacement between exposure masks used in the multiple exposure process.

[Another Manufacturing Method of Electro-Optical Device Substrate 124]
FIG. 9 is a process cross-sectional view showing another method for manufacturing a liquid crystal device to which the present invention is applied. In this embodiment, in the alignment mark forming process, a material that develops or changes color by being exposed is used to form a substrate on the substrate. An alignment mark is formed, and in the multiple exposure process, the alignment mark is exposed at the time of the first exposure to develop or change the color of the alignment mark.

  When such a method is adopted, first, as shown in FIG. 9A, after the alignment mark 250 is formed on the large substrate 400 (second substrate 120) by a method such as printing or transfer (alignment). Mark forming step), a positive type photosensitive resin 138 which is a kind of photosensitive material is applied to the large substrate 400 by, for example, a spin coating method (application step). Here, the alignment mark 250 is made of a material containing a photochromic compound, a monomer having a photopolymerizable unsaturated bond in the molecule, a photopolymerization initiator, a photoacid generator, etc. It is a material that causes

  Next, after drying and pre-baking the photosensitive resin 138, for example, the photosensitive resin 138 is exposed using the exposure mask 240 used in the process described with reference to FIG. 7D (first exposure). . At that time, the exposure mask 240 may be positioned by the alignment mark 259 and the translucent portion 243 (positioning step). Here, the exposure mask 240 has an exposure pattern for forming a portion where the photosensitive resin 138 is completely removed at the stage where the next development process is completed. That is, the fourth exposure mask 240 includes an exposure pattern including a light shielding portion 241 in a region other than the region corresponding to the opening 135 described with reference to FIG.

  Further, the exposure mask 240 is provided with a light transmitting portion 243 for partially exposing the alignment mark 250. Therefore, during the first exposure, a part of the alignment mark 250 is exposed and discolored or colored, and as a result, a substantial alignment mark 259 is formed at such a discolored or colored portion.

  Therefore, at the time of the second exposure, as shown in FIG. 9B, after aligning the large substrate 400 and the exposure mask 210 using the alignment marks 219 and 259 (positioning step), the photosensitive resin is used. 138 is exposed (second exposure). Here, the exposure mask 210 includes an exposure pattern including a light shielding portion 211 only in a region corresponding to the convex portion 133 described with reference to FIG.

  Next, as shown in FIG. 9C, after aligning the large substrate 400 and the second exposure mask 220 using alignment marks 229 and 159 (positioning step), the photosensitive resin 138 is exposed ( Third exposure). Here, the exposure mask 220 includes an exposure pattern including a light shielding portion 221 only in a region corresponding to the convex portions 132 and 133 described with reference to FIG.

  Next, as shown in FIG. 9D, after aligning the large substrate 400 and the exposure mask 230 using the alignment marks 239 and 159 (positioning step), the photosensitive resin 138 is exposed (fourth time). exposure). Here, the exposure mask 230 includes an exposure pattern including a light shielding portion 231 only in regions corresponding to the convex portions 131, 132, and 133 described with reference to FIG.

  Therefore, when the photosensitive resin 138 is developed (development process), as shown in FIG. 8A, the photosensitive resin 138 is removed according to the exposure amount, and the convex portions 131, 132, and 133 having different heights are formed. The formed underlayer 130 is formed. In addition, an opening 135 from which the photosensitive resin 138 is completely removed is formed in the base layer 130.

  Next, as shown in FIG. 8B, after forming a metal layer 145 such as aluminum or an aluminum alloy to be the reflective layer 140 with a substantially constant thickness so as to cover the base layer 130 by, for example, sputtering, A resist mask 260 is formed on the surface of the metal layer 145, and the metal film 145 is etched in this state. As a result, a portion of the metal layer 145 that is not covered with the resist mask 260 in the metal layer 125 is removed, and as described with reference to FIGS. 3A and 3B, the light transmission portion 142 is provided. A reflective layer 140 is formed. Since the subsequent steps are the same as those in the above embodiment, the description thereof is omitted.

  If comprised in this way, since subsequent positioning will be performed on the basis of the position of the exposure mask 240 in the case of the 1st exposure, the position shift of the exposure masks 210, 220, 230, 240 used in a multiple exposure process is ensured. Can be prevented.

[Other embodiments]
Note that the manufacture of the electro-optical device substrate 124 or the like may involve batch exposure of the large substrate 400 in addition to the stepper exposure of the large substrate 400. Even in such a case, as shown in FIG. 10A, the alignment mark 129 is formed outside the region 410 cut out as the electro-optical device substrate 124, while as shown in FIG. 10B. Alignment marks 219, 229, 239, and 249 are formed on any of the exposure masks 210, 220, 230, and 240 that collectively expose the large substrate 400. In the multiple exposure step P5, multiple exposure is performed on the photosensitive resin 138 by repeating batch exposure using a batch exposure mask (exposure masks 210, 220, 230, and 240) or by performing exposure using each exposure method. . Conventionally, such batch exposure has tended to have low positioning accuracy of the exposure masks 210, 220, 230, and 240 compared with step exposure. However, according to the present invention, high-accuracy exposure is possible even in batch exposure. It can be carried out. In this case, the alignment mark 129 may be formed at any position on the large substrate 400 as long as it can be used for positioning the exposure mask.

  Further, in the multiple exposure step P5, the exposure mask for step exposure shown in FIG. 5B and the exposure mask for batch exposure may be used in combination. In this case, multiple exposure of the photosensitive resin 1358 is performed by repeating step exposure using the step exposure mask and batch exposure using the batch exposure mask.

  Further, as the plurality of exposure masks 210, 220, 230, and 240, masks having different outer sizes may be used. With this configuration, exposure is performed with an exposure mask having a size corresponding to a portion to be exposed on the substrate. It can be carried out.

  In the above embodiment, the base layer 130 is formed using the positive photosensitive resin 138. However, the present invention is applied to the case where the base layer 130 is formed using the negative photosensitive resin 138. May be.

  In the above embodiment, the electro-optical device substrate 124 used in the transflective liquid crystal device 100 has been described. However, in the case of the electro-optical device substrate 124 used in the total reflection liquid crystal device 100, the opening 135 is provided. In addition, it is not necessary to form the light transmission part 142. The present invention may be applied to such a case.

  In addition, in the above embodiments, the electro-optical device including a liquid crystal panel using a TFD element as an active element has been described as an example. However, the electro-optical apparatus including a liquid crystal panel using a TFT as an active element, etc. The present invention may be applied to.

  In such a TFT active matrix type liquid crystal device, a wiring is formed on the lower layer side of the underlayer 130 for forming irregularities. Therefore, in the alignment mark forming step, wiring and other patterns may be formed on the substrate simultaneously with forming the alignment mark. Also in the TFD active matrix type liquid crystal device, when the base layer 130 for forming irregularities is formed toward the first substrate 110 (element substrate), wiring may be formed before the base layer 130 is formed. . Therefore, in the alignment mark formation step, wiring and other patterns may be formed on the substrate with copper, aluminum or the like simultaneously with forming the alignment mark.

  In the above embodiment, the present invention is applied to the exposure process of the photosensitive resin 138. However, the present invention is not limited to the exposure process to the photosensitive resin 138, and is not limited to the light irradiation (exposure) such as annealing to the substrate or a thin film formed on the substrate. The present invention may be applied.

[Example of mounting on electronic devices]
A liquid crystal device 100 to which the present invention is applied can be used as a display portion of a mobile phone 300 shown in FIG. Here, the mobile phone 300 includes an earpiece 320 and a mouthpiece 330 in addition to the plurality of operation buttons 310. In addition to the mobile phone 300, the liquid crystal device 100 is mounted on an electronic device such as a mobile computer, a digital camera, a movie camera, an in-vehicle device, an audio device, and a projector.

It is sectional drawing of the liquid crystal device to which this invention is applied. It is a disassembled perspective view which shows schematic structure of the liquid crystal device shown in FIG. (A), (b) is the top view for 1 dot of the board | substrate for electro-optical apparatuses used for the liquid crystal device based on this embodiment, respectively, and explanatory drawing which shows typically the BB 'line cross section. . FIG. 4 is a process diagram illustrating a method for manufacturing an electro-optical device substrate used in the liquid crystal device illustrated in FIG. 1. (A), (b) is explanatory drawing of the large sized board | substrate used for manufacture of the board | substrate for electro-optical devices used for the liquid crystal device shown in FIG. 1, respectively, and explanatory drawing of an exposure mask. FIG. 5 is a process cross-sectional view illustrating a method for manufacturing the electro-optical device substrate used in the liquid crystal device illustrated in FIG. 1. FIG. 5 is a process cross-sectional view illustrating a method for manufacturing the electro-optical device substrate used in the liquid crystal device illustrated in FIG. 1. FIG. 5 is a process cross-sectional view illustrating a method for manufacturing the electro-optical device substrate used in the liquid crystal device illustrated in FIG. 1. It is process sectional drawing which shows another manufacturing method of the board | substrate for electro-optical apparatuses to which this invention is applied. (A), (b) is explanatory drawing of another large sized substrate used for manufacture of the board | substrate for electro-optical devices used for the liquid crystal device shown in FIG. 1, respectively, and explanatory drawing of another exposure mask. It is explanatory drawing of the electronic device provided with the liquid crystal device to which this invention is applied. It is process sectional drawing which shows the manufacturing method of the conventional board | substrate for electro-optical devices.

Explanation of symbols

100 Liquid crystal device (electro-optical device), 110 First substrate, 120 Second substrate, 124 Electro-optical device substrate, 129, 250, 259 Substrate side alignment mark, 130 Underlayer, 131, 132, 133 Convex portion, 135 Opening, 138 Positive type photosensitive resin (photosensitive material), 140 Reflective layer, 142 Translucent part, 180 Liquid crystal (electro-optical material), 210, 220, 230, 240 Exposure mask, 219, 229, 239, 249 Exposure Mask alignment mark

Claims (7)

An alignment mark forming step for forming an alignment mark on the substrate;
An application step of applying a photosensitive material on the substrate;
A multiple exposure step of sequentially exposing the photosensitive material with a plurality of exposure masks having different exposure patterns;
A development step of developing the photosensitive material to form a base layer having convex portions having different heights;
A reflective layer forming step of forming a reflective layer on the underlayer,
The method of manufacturing a substrate for an electro-optical device according to claim 1, wherein a positioning step of positioning each of the exposure masks based on the alignment mark is performed at least before the second and subsequent exposures in the multiple exposure step.   2. The method for manufacturing a substrate for an electro-optical device according to claim 1, wherein in the alignment mark forming step, a wiring pattern is formed on the substrate simultaneously with the formation of the alignment mark. In claim 1, in the alignment mark forming step, the alignment mark is formed on the substrate using a material that develops or changes color when exposed.
In the multiple exposure step, the alignment mark is exposed at the time of initial exposure, and the alignment mark is colored or discolored. In any one of Claim 1 thru | or 3, in the said multiple exposure process, it exposes so that the one part area | region of the said photosensitive material may be removed in the said image development process,
In the reflective layer forming step, a region where no reflective layer is provided is formed in a region corresponding to the removed portion.   5. The method for manufacturing a substrate for an electro-optical device according to claim 1, wherein the plurality of exposure masks include masks having different outer sizes. 6. The exposure mask according to claim 1, wherein the plurality of exposure masks include a step exposure mask for step exposure of the substrate and a batch exposure mask for batch exposure of the substrate. ,
In the multiple exposure step, a step of performing step exposure using the step exposure mask and a step of performing batch exposure using the batch exposure mask are performed. . An alignment mark forming step of forming an alignment mark on one of the pair of substrates sandwiching the electro-optic material;
An application step of applying a photosensitive material on the one substrate;
A multiple exposure step of sequentially exposing the photosensitive material with a plurality of exposure masks having different exposure patterns;
A development step of developing the photosensitive material to form a base layer having convex portions having different heights;
A reflective layer forming step of forming a reflective layer on the underlayer,
In the multiple exposure step, a positioning step of positioning each of the exposure masks based on the alignment mark is performed at least before each second and subsequent exposures.

Images