JP2009075502A - Method of manufacturing color filter substrate and method of manufacturing electro-optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a color filter having excellent color reproducibility by forming a uniform film thickness resist by performing exposure of a substrate from upper and lower sides. <P>SOLUTION: The method has processes S2, S4 and S6 in which the color resist of a plurality of colors is formed on the substrate for the respective colors, and processes S3, S5 and S7 in which a patterning is performed by exposing the color resist of the respective colors, wherein the patterning process by exposing includes processes S11 and S12 in which the substrate is irradiated with exposure light from both the upper and lower sides for the color resist of at least one color among the plurality of colors. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a color filter substrate having a color filter layer made of a color resist and a method for manufacturing an electro-optical device.

  An electro-optical device, for example, a liquid crystal device using liquid crystal as an electro-optical material, is widely used as a display device in place of a cathode ray tube (CRT) in a display unit of various information processing devices, a liquid crystal television, and the like.

  Such a liquid crystal device includes, for example, a pixel electrode arranged in a matrix, an element substrate provided with a switching element such as a TFT (Thin Film Transistor) electrically connected to the pixel electrode, It is composed of a counter substrate on which a counter electrode facing the pixel electrode is formed, and a liquid crystal as an electro-optical material filled between the two substrates.

  The TFT is turned on by a scanning signal (gate signal) supplied via the scanning line (gate line). An image signal having a voltage corresponding to the gradation is applied to the pixel electrode through the data line (source line) in a state where the scanning signal is applied to make the switching element conductive. Then, charges corresponding to the voltage of the image signal are accumulated in the pixel electrode and the counter electrode. After the charge accumulation, even if the scanning signal is removed and the TFT is turned off, the charge accumulation state in each electrode is maintained by the capacitance of the liquid crystal layer, the accumulation capacitance, and the like.

  In this way, when each switching element is driven and the amount of charge to be stored is controlled according to the gradation, the alignment state of the liquid crystal changes for each pixel, the light transmittance changes, and the brightness changes for each pixel. be able to. In this way, gradation display is possible.

  By the way, in a liquid crystal device, a color filter may be formed between a counter substrate and a counter electrode in order to enable color display. A protective film layer is formed on the color filter, and a counter electrode and an alignment film are formed on the protective film layer. The color filter is colored red (R), green (G), and blue (B) corresponding to each pixel, and performs color display with each pixel as a red pixel, a green pixel, and a blue pixel.

Patent Document 1 discloses a technique for improving the characteristics of a planarizing film after forming a color resist pattern.
JP-A-8-304619

  Conventionally, as a color filter, there is one that employs a negative type color resist (negative resist). A color filter is obtained by exposing and patterning a negative resist of R, G, B so as to have a predetermined color arrangement.

  However, depending on the wavelength of the exposure light, the characteristics of the negative resist, etc., a uniform profile may not be obtained during exposure. For example, in the case of a B negative resist, the exposure profile is inversely tapered, and the thickness of the film (residual film thickness) remaining after exposure differs between the center and the peripheral portion of the B color negative resist. There is a difference.

  The chromaticity characteristics of the color filter depend on the film thickness of the negative resist. Therefore, when a color filter made of a negative resist having a non-uniform film thickness is used, there is a problem that chromaticity is shifted and color reproducibility is poor.

  The present invention has been made in view of such problems, and by performing exposure from both the front surface and the back surface of the substrate, it is possible to make the resist film thickness uniform, and high color without color unevenness. It is an object of the present invention to provide a method for manufacturing a color filter substrate and a method for manufacturing an electro-optical device that can achieve reproducibility.

  The method for manufacturing a color filter substrate according to the present invention includes a step of forming a color resist of a plurality of colors on a substrate for each color, and a step of exposing and patterning the color resist for each color. The patterning step includes irradiating exposure light from both above and below the substrate for the color resist of at least one of the plurality of colors.

  According to such a configuration, a color resist is formed on the substrate and exposed to a predetermined pattern. By repeating the formation and exposure of the color resist for each color, a color filter substrate having a desired color arrangement is obtained. At least one of the color resists of each color is irradiated with exposure light from both above and below the substrate. As a result, the exposure profile can be made uniform, the remaining resist film thickness by exposure can be made uniform, the filter characteristics can be made uniform, and a color filter substrate having excellent color reproducibility without color unevenness can be obtained. Can do.

  Further, the step of irradiating exposure light from both above and below the substrate includes a step of performing exposure using a photomask on one of the upper and lower sides of the substrate and exposing the entire surface of the substrate on the other side. Features.

  According to such a configuration, the exposure light from the other is performed on the entire surface of the substrate, so that the process can be easily managed.

  Further, the step of exposing the entire surface of the substrate is performed with an exposure amount smaller than an exposure threshold at which a residual film thickness larger than 0 is generated by the exposure.

  According to such a configuration, in the region where the exposure from one side of the substrate is not performed, the remaining film is not generated only by the exposure from the other side of the substrate, and a reliable pattern formation is possible.

  The step of exposing the entire surface of the substrate is performed on a blue color resist.

  According to such a configuration, by irradiating exposure light from both above and below the substrate, an inversely tapered exposure profile in the case of exposing a blue color resist can be made uniform, and color unevenness is caused. A color filter substrate having excellent color reproducibility can be obtained.

  In addition, a step of forming a light shielding film on the substrate is provided before the step of forming the color resist for each color.

  In the step of forming the color resist and the step of exposing and patterning the color resist for each color, a green color resist of a plurality of colors is first exposed and patterned.

  According to such a configuration, the film thickness can be easily managed in the patterning performed first, and the film thickness of the green resist can be easily made uniform. Thereby, a color filter substrate with more excellent color reproducibility can be obtained.

  An electro-optical device manufacturing method according to the present invention is an electro-optical device manufacturing method configured by interposing an electro-optical material between a first substrate and a second substrate arranged to face each other. Forming a color resist for each color on the substrate for each color; and exposing and patterning the color resist for each color, wherein the exposing and patterning includes: The color resist of at least one color includes a step of irradiating exposure light from both above and below the first substrate.

  According to such a configuration, the color resist is formed on the first substrate constituting the electro-optical device, and exposed to a predetermined pattern. By repeating the formation and exposure of the color resist for each color, a color filter substrate having a desired color arrangement is obtained. At least one of the color resists of each color is irradiated with exposure light from both above and below the first substrate. As a result, the exposure profile can be made uniform, the remaining resist film thickness by exposure can be made uniform, the filter characteristics can be made uniform, and a color filter substrate having excellent color reproducibility without color unevenness can be obtained. Can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing a method for manufacturing a color filter substrate according to an embodiment of the present invention, and FIG. 2 is a flowchart showing a specific procedure of an exposure / patterning step in FIG. FIG. 3 is a plan view showing a liquid crystal device configured using the color filter substrate manufactured by the method for manufacturing the color filter substrate of FIG. 1 as a counter substrate. FIG. 4 is a cross-sectional view of the liquid crystal device after the assembly process in which the element substrate and the counter substrate are bonded to each other and the liquid crystal is sealed is cut along the line HH ′ in FIG.

  First, a liquid crystal device configured using a color filter substrate will be described with reference to FIGS. As shown in FIGS. 3 and 4, the element substrate 10 and the counter substrate 20 that is a color filter substrate are disposed to face each other, and a liquid crystal 50 is sealed between the element substrate 10 and the counter substrate 20. On the element substrate 10, pixel electrodes and the like constituting pixels are arranged in a matrix.

  In the pixel area, a plurality of scanning lines (not shown) and a plurality of data lines are wired so as to intersect with each other, and pixel electrodes 9a are arranged in a matrix in an area partitioned by the scanning lines and the data lines. A TFT (not shown) is provided corresponding to each intersection of the scanning line and the data line, and the pixel electrode 9a is electrically connected to the TFT.

  The TFT is turned on by the ON signal of the scanning line, whereby the image signal supplied to the data line is supplied to the pixel electrode 9a. A voltage between the pixel electrode 9 a and the counter electrode 21 provided on the counter substrate 20 is applied to the liquid crystal 50.

  On the other hand, the counter substrate 20 is provided with a first light-shielding film 23 in a region facing the data line, scanning line, and TFT formation region of the TFT array substrate, that is, in a non-display region of each pixel. The first light shielding film 23 prevents incident light from the counter substrate 20 side from entering the TFT channel region, source region, and drain region.

  A color filter layer 24 is provided on the first light shielding film 23. An overcoat layer 25 is provided on the color filter layer 24. The overcoat layer 25 is a layer formed of acrylic resin, epoxy resin, or the like. The overcoat layer 25 flattens the unevenness due to the color filter layer 24 and the first light shielding film 23, and prevents the organic material from seeping out from the color filter layer 25 and the first light shielding film 23 to deteriorate the liquid crystal 50. Have a role.

  A counter electrode (common electrode) 21 is formed over the entire surface of the substrate 20 on the overcoat layer 25. An alignment film 22 made of a polyimide-based polymer resin is laminated on the counter electrode 21 and rubbed in a predetermined direction.

  The counter substrate 20 is provided with a light shielding film 42 as a frame for partitioning the display area. The light shielding film 42 is formed of, for example, the same or different light shielding material as the light shielding film 23.

  A sealing material 41 that encloses liquid crystal in a region outside the light shielding film 42 is formed between the element substrate 10 and the counter substrate 20. The sealing material 41 is disposed so as to substantially match the contour shape of the counter substrate 20, and fixes the element substrate 10 and the counter substrate 20 to each other. The sealing material 41 is missing in a part of one side of the element substrate 10, and a liquid crystal injection port 78 for injecting the liquid crystal 50 is formed in the gap between the bonded element substrate 10 and the counter substrate 20. The After the liquid crystal is injected from the liquid crystal injection port 78, the liquid crystal injection port 78 is sealed with a sealing material 79. Thus, the liquid crystal 50 is sealed between the element substrate 10 and the counter substrate 20.

  A data line driving circuit 61 and a mounting terminal 62 are provided along one side of the element substrate 10 in a region outside the sealing material 41 of the element substrate 10, and scanning lines are provided along two sides adjacent to the one side. A drive circuit 63 is provided. On the remaining side of the element substrate 10, a plurality of wirings 64 are provided for connecting between the scanning line driving circuits 63 provided on both sides of the screen display area. In addition, a conductive material 65 for electrically connecting the element substrate 10 and the counter substrate 20 is provided in at least one corner of the counter substrate 20.

  The color filter layer 24 is configured by exposing and patterning a color resist. For example, a negative type is adopted as the color resist. The color resist is a resin, pigment, and photosensitizer dissolved therein. In a negative type color resist, by exposure, the photosensitive agent reacts to harden the exposed resin and pigment. The color filter layer 24 having a predetermined color arrangement can be formed by sequentially exposing and patterning the color resists of the respective colors in accordance with the R, G, and B color arrangements.

  Next, a method for manufacturing the color filter substrate shown in FIG. 1 will be described. The counter substrate 20 in FIGS. 3 and 4 is manufactured by the method for manufacturing the color filter substrate in FIG.

  In step S <b> 1, a first light shielding film 23 that also functions as a black matrix (BM) is formed on the substrate 20. Next, in step S <b> 2, a green (G) negative resist (G resist) is formed on the entire surface of the first light shielding film 23 and the substrate 20. Next, in step S3, exposure and patterning are performed.

  Similarly, in steps S4 and S5, a red (R) negative resist (R resist) is formed on the entire surface of the first light shielding film 23 and the substrate 20, and exposure and patterning are performed.

  Similarly, in steps S6 and S7, a blue (B) negative resist (B resist) is formed on the entire surface of the first light shielding film 23 and the substrate 20, and exposure and patterning are performed.

  Thus, the color filter layer 24 is configured by patterning the G resist, the R resist, and the B resist according to a predetermined color arrangement. The G filter part composed of the G resist, the R filter part composed of the R resist, and the B filter part composed of the B resist are arranged according to a predetermined color arrangement and transmit green light, red light or green light, respectively. To do.

  Note that the G filter portion constituting the color filter layer 24 has higher sensitivity than the other color filter portions. Therefore, a color filter having more excellent color reproducibility can be obtained by making the G resist film thickness uniform. A color filter using a negative resist can form a desired color array by sequentially exposing and patterning resists of respective colors. Since the resists of the respective colors are sequentially patterned, it is difficult to manage the film thickness due to the step difference caused by the already formed resist in the patterning for the second and subsequent colors. Therefore, a color filter having excellent color reproducibility can be configured by first forming a G resist that has the greatest influence on color reproducibility and is easy to manage the film thickness.

  In the present embodiment, at least one of the color resists is patterned by performing not only exposure from above the substrate 20 but also exposure from below the substrate 20, thereby making the film thickness uniform. We are trying to make it. In particular, for the B resist, since the exposure profile is inversely tapered, it is better to perform exposure from both.

  FIG. 5 is an explanatory diagram for explaining the exposure and patterning of the B resist in the present embodiment. FIG. 6 is an explanatory diagram for explaining exposure when exposure from below the substrate is not performed.

  As shown in FIGS. 5A and 6A, a reticle 71 having a photomask 72 formed on a portion other than the B filter portion is disposed above the substrate 20 on which the B resist 70 is formed, and is directed downward. As indicated by the arrow, the B resist 70 is irradiated with exposure light having a predetermined wavelength from above the substrate via the reticle 71.

  As shown in FIG. 6A, when exposure is performed only from above the substrate, the exposure profile becomes a reverse taper shape. As a result, a difference in film thickness is caused between the center and the peripheral portion of the remaining resist as shown in FIG.

  Therefore, in the present embodiment, not only the exposure from the upper side of the substrate in step S11 of FIG. The entire surface of 20 is irradiated with exposure light (step S12).

  FIG. 7 is a graph showing the relationship between the exposure amount and the remaining film thickness, with the exposure amount on the horizontal axis and the remaining film thickness on the vertical axis. Now, let the exposure amount at which the remaining film thickness with respect to the exposure amount be greater than 0 be the exposure threshold Eth. As shown in FIG. 7, when the exposure amount exceeds the exposure threshold Eth, a remaining film thickness occurs. When the exposure amount exceeds a predetermined value, the change in the remaining film thickness becomes small.

  In the present embodiment, exposure control is performed so that the exposure amount obtained by combining the exposure amount from above the substrate and the exposure amount from below the substrate does not exceed the exposure threshold Eth for the other color resist regions. It has become.

  FIG. 8 is an explanatory diagram for explaining the remaining film thickness by this control. A hatched portion rising to the right in FIG. 8 indicates a region affected by exposure (upward exposure) from above the substrate. This exposure profile is reversely tapered as shown in FIG. 8, and the resist 70 is not sufficiently exposed on the substrate surface side.

  On the other hand, the diagonally downward slanted line portion in FIG. 8 indicates an exposure region of exposure (lower exposure) from below the substrate. In the example of FIG. 8, downward exposure is performed on the entire substrate. The exposure amount of the lower exposure is smaller than the exposure threshold Eth. Therefore, the remaining film thickness of the resist is 0 in a portion other than the pattern range where the resist is left by the exposure, that is, a portion irradiated only with the lower exposure light.

  On the other hand, in the pattern range, upper exposure light and lower exposure light are irradiated. The upper exposure light has an inversely tapered exposure profile, and the lower exposure light has an exposure profile opposite to the exposure profile. Therefore, by appropriately setting the exposure amount of the upper exposure light and the exposure amount of the lower exposure light, the exposure amount can be made larger than the exposure threshold Eth for the region where the upper and lower exposures are performed, and the exposure profile. Can be made uniform. In this way, a B resist having a uniform film thickness can be formed as shown in FIG.

  Next, an acrylic resin, an epoxy resin, or the like is applied so as to cover the color filter layer 23 to form an overcoat layer 25. Next, the counter electrode 21 is formed on the surface of the overcoat layer 25 using ITO, and an alignment film 22 such as polyimide is formed and a rubbing process is performed.

  Thus, in this embodiment, at least one color resist among the color resists is exposed not only from above the substrate but also from below the substrate. Thereby, the exposure profile can be made uniform, and the residual film thickness of the resist can be made uniform. Since the resist film thickness can be made uniform, the characteristics of the color filter can be improved, and good color reproducibility without color unevenness can be obtained. Further, since the exposure amount from the lower side of the substrate is set to be smaller than the exposure threshold Eth, the other color filter portions are not adversely affected by the exposure from the lower side. In addition, exposure from below may be performed on the entire surface of the substrate, and process management is easy.

  In the above embodiment, the exposure amount from the lower side of the substrate is made smaller than the exposure threshold Eth to avoid the influence on other color filter units. Alternatively, a reticle may be used so that only the necessary portions are exposed. In this case, it is not necessary to limit the exposure amount from below the substrate.

  In addition, in FIG. 2, the example in which the exposure from the upper side of the substrate is first performed and then the exposure from the lower side of the substrate is described. In addition, exposure from above and below the substrate may be performed simultaneously.

  The present embodiment can also be applied to an overlapping BM that constitutes a black matrix by overlapping R, G, and B filter portions. In the overlapping BM, patterning is performed so as to leave the R, G, B resist in the black matrix portion when the R, G, B resist is exposed. Accordingly, a color filter layer corresponding to a predetermined color arrangement can be formed, and a portion where the R, G, and B resists are overlapped can function as a black matrix. In this overlapping BM, considering that the film thickness of the B filter portion has a large influence on black, exposure and patterning of the B resist are performed in the process of the first color, which is the easiest to manage the film thickness.

  In each of the above-described embodiments, the example using the negative type resist has been described. However, it is obvious that the present invention can be similarly applied to the case where the positive type resist is used.

  In the above embodiment, the example in which the color filter substrate is used as the counter substrate has been described. However, the element substrate may be a color filter substrate.

  The color filter substrate of the present invention is not limited to a passive matrix type liquid crystal display panel, but an active matrix type liquid crystal panel (for example, a liquid crystal display panel including a TFT (thin film transistor) or a TFD (thin film diode) as a switching element). It is possible to apply to the same. Further, the present invention can be similarly applied to an on-the-chip color filter (OCCF) in which a color filter is formed on an element substrate. In addition to liquid crystal display panels, electroluminescence devices, organic electroluminescence devices, plasma display devices, electrophoretic display devices, devices using electron emission (such as Field Emission Display and Surface-Conduction Electron-Emitter Display), DLP ( The present invention can be similarly applied to various electro-optical devices such as Digital Light Processing (aka DMD: Digital Micromirror Device). The present invention is also applicable to a display device for forming an element on a semiconductor substrate, for example, LCOS (Liquid Crystal On Silicon). In LCOS, a single crystal silicon substrate is used as an element substrate, and a transistor is formed on a single crystal silicon substrate as a switching element used for a pixel or a peripheral circuit. In addition, a reflective pixel electrode is used for the pixel, and each element of the pixel is formed under the pixel electrode.

The flowchart which shows the manufacturing method of the color filter board | substrate which concerns on one embodiment of this invention. The flowchart which shows the specific procedure of the exposure and patterning process in FIG. The top view which shows the liquid crystal device comprised using the color filter substrate manufactured by the manufacturing method of the color filter substrate of FIG. 1 as a counter substrate. FIG. 4 is a cross-sectional view of the liquid crystal device after the assembly process in which the element substrate and the counter substrate are bonded to each other and the liquid crystal is sealed is cut along the line HH ′ in FIG. 3. Explanatory drawing for demonstrating exposure and patterning of B resist in this Embodiment. Explanatory drawing for demonstrating the exposure in case the exposure from the lower part of a board | substrate is not performed. The graph which shows the relationship between an exposure amount and a residual film thickness, taking exposure amount on a horizontal axis and taking a residual film thickness on a vertical axis | shaft. Explanatory drawing for demonstrating the residual film thickness by the exposure control of this Embodiment.

Explanation of symbols

    S1, BM formation step, S2, S4, S6 ... Resist formation step, S3, S5, S7 ... Exposure / patterning step, S11 ... Upper exposure, S12 ... Lower exposure.

Claims (7)

Forming a plurality of color resists for each color on the substrate;
And exposing and patterning the color resist for each color,
The step of exposing and patterning includes a step of irradiating exposure light from both above and below the substrate for a color resist of at least one of the plurality of colors. Manufacturing method.   The step of irradiating the exposure light from both above and below the substrate includes a step of performing exposure using a photomask on one of the upper and lower sides of the substrate and exposing the entire surface of the substrate on the other side. The method for producing a color filter substrate according to claim 1.   3. The method of manufacturing a color filter substrate according to claim 2, wherein the step of exposing the entire surface of the substrate is performed with an exposure amount smaller than an exposure threshold at which a residual film thickness greater than 0 is generated by exposure.   The method for manufacturing a color filter substrate according to claim 3, wherein the step of exposing the entire surface of the substrate is performed on a blue color resist.   5. The color filter substrate according to claim 1, further comprising a step of forming a light-shielding film on the substrate before the step of forming the color resist for each color. Method.   The green color resist of a plurality of colors is first exposed and patterned in the step of forming the color resist and the step of exposing and patterning the color resist for each color. A method for manufacturing a color filter substrate. A method for manufacturing an electro-optical device configured by interposing an electro-optical material between a first substrate and a second substrate arranged to face each other,
Forming a plurality of color resists for each color on the first substrate;
And exposing and patterning the color resist for each color,
The exposure and patterning step includes a step of irradiating exposure light from both above and below the first substrate for the color resist of at least one of the plurality of colors. A method for manufacturing an electro-optical device.

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