JP2007279378A - Manufacturing method of color filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a color filter, with which cracks will be not generated, even when a transparent conductive film, formed on a color filter layer having a complicated structure, is affected by thermal stress or by a next process. <P>SOLUTION: The manufacturing method of the color filter includes steps for film-forming a black matrix and colored layers of a plurality of colors on a transparent substrate to form the color filter layer; applying pressure to the surface of the color filter layer to make compressive stress generated at only a surface layer part of the color filter layer; and forming the transparent conductive film on the color filter layer by a sputtering method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a color filter, and more particularly to a method for manufacturing a color filter in which a transparent conductive film formed on the surface is not damaged.

  In general, a color filter is configured by sequentially forming a black matrix and an RGB colored layer on a transparent substrate, and a transparent conductive film is formed on the color filter. As the transparent conductive film, an ITO film (mixture of indium oxide and tin oxide) formed by a sputtering method is usually used.

  Regarding the film formation of the transparent conductive film, a method of forming the transparent conductive film at room temperature and then crystallizing it by annealing, a method of forming the film at a temperature higher than the crystallization temperature, about 100 ° C. There is a method of obtaining desired characteristics by annealing after heating at a low temperature before crystallization. Recently, in order to reduce damage to the color filter layer, a method of forming at room temperature or low temperature heating is common.

  Recently, liquid crystal panels suitable for various applications and needs such as reflective liquid crystal panels, transflective liquid crystal panels, and wide viewing angle liquid crystal panels have been developed. In the color filter layer, in addition to the RGB colored layer, a complex color filter, such as a white layer or a four to six color filter using a complementary color, or a color filter having a light scattering film formed on the colored layer, etc. A variety of varieties are emerging. In addition, the black matrix has a narrower line width to improve the aperture ratio and make it brighter.

  With respect to the color filter having such a configuration, photolithography technology has been improved, and it has become possible to meet the required needs. However, since these different coloring materials are overlapped and the narrow width of the rack matrix is reduced, it is difficult to control the overlapping portion of the pattern. In some cases, three different resins may overlap, and in such a case, it is very difficult to control the overlapping portion.

  The formation of the transparent conductive film on the color filter layer having such a complicated configuration needs to be performed after performing a smoothing process such as polishing, but even in such a case, the colored layer and the black matrix layer as the base are It behaves complicatedly, such as changes in shape due to thermal stress. Therefore, simply controlling the stress of the transparent conductive film does not alleviate the overall thermal stress, but causes cracks in the transparent conductive film due to thermal stress and subsequent processes.

  Such a problem is usually solved by adjusting the internal stress of the transparent conductive film because the base is a resin, but this method alone has a limit.

  In addition, there are some that do not require smoothing processing, and among the three-dimensional changes, the conventional methods cannot follow the heat treatment and the process conditions of the next process.

  On the other hand, in order to prevent cracks in the thin film formed on the substrate, it has been proposed to increase the packing density of the thin film and leave compressive stress in the thin film (see, for example, Patent Document 1).

However, the thin film in this case is a dielectric multilayer film made of an inorganic material, and increasing the packing density to leave compressive stress cannot be applied to a color filter layer made of an organic resin.
Japanese Patent Application No. 2005-266069

  The present invention is made under the circumstances as described above, and manufacture of a color filter in which cracks do not occur even if the transparent conductive film formed on the color filter layer having a complicated structure is affected by thermal stress or the next process. It aims to provide a method.

  In order to solve the above problems, the present invention forms a black matrix and a colored layer of a plurality of colors on a transparent substrate, and forms a color filter layer, applying pressure to the surface of the color filter layer, There is provided a method for producing a color filter, comprising: a step of generating a compressive stress in a surface layer portion of the color filter layer; and a step of forming a transparent conductive film on the color filter layer by a sputtering method.

  In such a method for producing a color filter, it is desirable to apply pressure to the surface of the color filter layer by causing fine particles to project on the surface of the color filter layer by the pressure of fluid. In particular, the fine particle projection by the pressure of the fluid onto the surface of the color filter layer can be performed by ejecting the fine particles and the fluid from the two-fluid shower. Moreover, the fine particle can be projected by the pressure of the fluid onto the surface of the color filter layer by ejecting a mixture of the fine particle and the liquid from the two-fluid shower.

  Alternatively, the fine particles can be projected by the pressure of the fluid onto the surface of the color filter layer by ejecting the fine particles and the liquid separately.

  It is desirable to use fine particles having a particle size of 0.05 μm to 10 μm. Examples of such fine particles include alumina, zirconia, silicon oxide, silicon nitride, silicon carbide, magnesium oxide, titanium oxide, zinc oxide, indium oxide, tin oxide, acrylic resin, phenol resin, epoxy resin, polyimide resin, polyurethane resin, Mention may be made of those selected from the group consisting of melamine resins and mixtures of two or more thereof.

  The fine particles may be accelerated together with a liquid having a pressure of 0.05 MPa to 5 MPa and projected onto the surface layer portion of the color filter layer.

  The present invention also provides a color filter produced by the above method for producing a color filter.

  According to the present invention, a transparent conductive film is formed on the color filter layer by sputtering after applying pressure to the surface of the color filter layer and generating a compressive stress on the surface layer portion of the color filter layer. The conductive film is not cracked by thermal stress caused by the structure and material of the underlying color filter layer and by subsequent processes.

  Hereinafter, the best mode of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view illustrating a manufacturing process of a color filter according to an embodiment of the present invention.

   As shown in FIG. 1A, first, a black matrix 2 for improving contrast is provided on a transparent substrate 1.

  As the transparent substrate 1, a known transparent substrate material such as a glass substrate, a quartz substrate, or a plastic substrate can be used.

  The black matrix 2 can be formed using a known method. For example, a method of forming a thin film of metal or metal oxide on a substrate by a method such as sputtering, patterning it by a technique such as etching, and a coloring agent such as a pigment or a dye in the photosensitive resin composition Can be formed as a photosensitive resin composition layer on a substrate and formed by a photolithography method, and a method in which a black pigment and a thermosetting resin are dissolved in a solvent and printed.

Next, as shown in FIG. 1B, red (R), green (G), and blue (B) colored pixel patterns 3 (R), 3 (3) are formed in the openings of the black matrix 2 by photolithography. G) A color filter layer 3 made of 3 (B) is formed. Formation of a pixel pattern by photolithography is performed by forming a predetermined colored resin composition layer on the transparent substrate 1 on which the black matrix 2 is formed, exposing it, and removing unexposed portions that become unnecessary portions. .

  Examples of the method for providing the colored resin composition layer include known methods such as a bar coater, an applicator, a wire bar, a spin coater, a roll coater, a slit coater, a curtain coater, a die coater, and a comma coater. As an exposure method, for example, a proximity method using a photomask in which a light-shielding part is formed by ultraviolet light using an ultrahigh pressure mercury lamp or a semiconductor laser as a light source, or mirror projection using an optical system using convex and concave mirrors. And a divided exposure method in which a projection lens is provided and the irradiation surface is divided. As the developer, an organic solvent system or an alkaline aqueous solution system is generally used, but an inorganic alkali system is preferable from the viewpoint of ensuring environmental safety.

As the colorant of the colored resin composition, conventionally known pigments, dyes and the like can be used. The thermosetting resin used in the colored resin composition is appropriately selected from known color filter substrate materials in relation to the colorant.

  Next, pressure is applied to the surface of the color filter layer 3 formed as described above to generate a compressive stress in the surface layer portion. That is, when pressure is applied to the surface of the color filter layer, a force is generated to spread in the horizontal direction on the surface layer portion. This force shows a compressive stress with respect to the inside of the color filter layer 3 or the substrate. This compressive stress is about 0.1 MPa to 10 MPa, and greatly depends on the configuration and material of the resin. Therefore, it is difficult to specifically limit the numerical value of the compressive stress, and it is necessary to select an optimum value according to the resin material constituting the color filter layer 3 and the black matrix 2.

  As a method of applying pressure to the surface of the color filter layer 3, a method of using a fluid, particularly a water flow, is preferable because fine adjustment is easier than a blast treatment using an air flow or the like. In addition, when accelerating the fine particles, the air flow generates an air resistance with the surroundings and is difficult to control. However, in the method using the water flow, since the kinetic energy is large, the air resistance can be ignored.

  Further, by using a water flow, there is an advantage that contamination by dust can be prevented, the effect of cleaning the substrate surface can be obtained, and the circulation of fine particles can be performed.

  In the method using a water flow, it is preferable to spray a dispersion in which fine particles and water are mixed and directly hit the surface of the color filter layer. According to this method, there are advantages that fine particle dispersibility, fine particle concentration, and the like can be finely adjusted and that fine particles can be circulated.

  A two-fluid shower can be used as a means for injecting such a mixture of fine particles and water dispersed.

  Alternatively, fine particles and water can be separately projected on the surface of the color filter layer 3. This method is particularly effective when used for an object that is relatively unfavorable for contamination and that is intended for relatively light processing on the surface layer.

  It is preferable that the diameter of the fine particles used is smaller than the pixel size of the color filter because the surface can be treated evenly. However, if it is too small, the effect of the treatment cannot be obtained. Therefore, the diameter of the fine particles is desirably in the range of 0.05 μm to 10 μm. A particularly preferable range is 0.1 μm to 3 μm. According to the fine particles having such a particle size, it is possible to perform the processing evenly between the inter-color portions and the overlapping portions of the colored layers, and the processing conditions for the surface layer portion are in a range that is easier to control.

  The material of fine particles is alumina, zirconia, silicon oxide, silicon nitride, silicon carbide, magnesium oxide, titanium oxide, zinc oxide, indium oxide, tin oxide, acrylic resin, phenol resin, epoxy resin, polyimide resin, polyurethane resin, melamine resin , And a group consisting of a mixture of two or more of these.

  In particular, oxide particles such as alumina and zirconium oxide are preferable because they can be processed without contaminating the surface layer portion. Moreover, resin particles, such as a phenol resin and an acrylic resin, may be sufficient. The resin-based material has a lighter pressure on the surface layer portion, and is therefore more effective for processing that requires fine adjustment.

  When oxide particles such as alumina are used, finer adjustments such as water pressure and flow rate are required. If the water pressure is too strong, the colored layer will be damaged, so great care must be taken, but resin particles have a wider margin.

  The material of the resin is not particularly limited, but an acrylic or phenolic material that is relatively available is preferable because it is inexpensive, has a uniform particle size, and is stable in quality.

  The water pressure is preferably in the range of 0.05 MPa to 5 MPa because stress is generated only in the surface layer portion of the color filter layer. This pressure range is within the pressure control range of a general two-fluid shower, which is preferable for making manufacturing equipment inexpensive. The pressure can be processed only on the surface layer by restricting the flow rate and controlling the pressure. It becomes.

  As shown in FIG. 1C, the transparent conductive film 4 is formed on the color filter layer 3 whose surface has been treated as described above, for example, by sputtering. The film thickness and material of the transparent conductive film 4 may be the same as those of the transparent conductive film used for a color filter for a liquid crystal display panel.

  In the transparent conductive film 4 formed in this way, compressive stress is generated in the surface layer portion of the underlying color filter layer 3, so that thermal stress due to the structure and material of the color filter layer 3 and subsequent processes However, cracks do not occur.

  Hereinafter, the present invention will be described more specifically by showing examples of the present invention.

Example 1
After forming a resin black matrix on a glass substrate, a color filter layer was formed by laminating three colored resins of R, G, and B using a photolithography technique. The overlap amount of the formed three colored resin layers and the black matrix layer was 3 μm, and the average step between the colored resin layer and the black matrix layer was 0.8 μm.

  Thereafter, a white colored resin layer was further formed to form a four-color filter layer.

  Next, using a two-fluid shower nozzle, a solution obtained by mixing pure water and phenol resin fine particles was sprayed onto the surface of the four-color filter layer. Thereby, compressive stress was generated on the surface of the four-color filter layer. The sprayed solution was obtained by dispersing phenol resin particles having an average particle diameter of 2 μm in 10% by weight pure water. The injected water pressure was 0.1 MPa.

  The solution was sprayed while passing the substrate under a slit type two-fluid nozzle. The conveyance speed of the substrate was 1.5 m / min.

  Although the compressive stress is generated in the color filter layer by the injection of such a solution, the compressive stress is generated only in the surface layer portion of the color filter layer, and the value thereof is less than 0.1 MPa. By such treatment, the development residue present in the color filter layer and the glass substrate portion on the outer periphery thereof could be removed.

  Thereafter, the substrate provided with the color filter layer was washed, fine particles and residues were removed and dried, and then a transparent conductive film was formed on the color filter layer by a sputtering method. The transparent conductive film was an ITO (mixed oxide of indium oxide and tin oxide) film having a thickness of 150 nm, and the film could be formed without heating.

  After forming the transparent conductive film, annealing treatment was performed to complete a color filter having predetermined characteristics.

  The stress of the ITO film at this time was a compressive stress of 50 MPa when formed on a Si substrate and measured. The ITO film formed on the color filter layer did not cause cracks even after the subsequent photospacer formation step.

Example 2
After forming a resin black matrix on a glass substrate, a color filter layer was formed by laminating three colored resins of R, G, and B using a photolithography technique. The overlap amount of the formed three colored resin layers and the black matrix layer was 3 μm, and the average step between the colored resin layer and the black matrix layer was 0.8 μm.

  Next, using a two-fluid shower nozzle, a solution in which pure water and acrylic resin fine particles were mixed was sprayed onto the surface of the color filter layer. Thereby, compressive stress was generated on the surface of the color filter layer. The sprayed solution was obtained by dispersing acrylic resin particles having an average particle diameter of 0.7 μm in 10% by weight pure water. The injected water pressure was 0.1 MPa.

  The solution was sprayed while passing the substrate under a slit type two-fluid nozzle. The conveyance speed of the substrate was 1.5 m / min.

  Although the compressive stress is generated in the color filter layer by the injection of such a solution, the compressive stress is generated only in the surface layer portion of the color filter layer, and the value thereof is less than 0.1 MPa. By such treatment, the development residue present in the color filter layer and the glass substrate portion on the outer periphery thereof could be removed.

  Thereafter, the substrate provided with the color filter layer was washed, fine particles and residues were removed and dried, and then a transparent conductive film was formed on the color filter layer by a sputtering method. The transparent conductive film was an ITO (mixed oxide of indium oxide and tin oxide) film having a thickness of 150 nm, and the film could be formed without heating.

  After forming the transparent conductive film, annealing treatment was performed to complete a color filter having predetermined characteristics.

  The stress of the ITO film at this time was a tensile stress of 10 MPa when formed on a Si substrate and measured. The ITO film formed on the color filter layer did not cause cracks even after the subsequent photospacer formation step.

Sectional drawing which shows the manufacturing process of the color filter which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Black matrix, 3 ... Color filter layer, 4 ... Transparent electrically conductive film.

Claims (9)

Forming a color filter layer by forming a black matrix and a colored layer of a plurality of colors on a transparent substrate;
Applying pressure to the surface of the color filter layer to generate a compressive stress in a surface layer portion of the color filter layer, and forming a transparent conductive film on the color filter layer by a sputtering method. A method for producing a color filter.   2. The method for producing a color filter according to claim 1, wherein the pressure is applied to the surface of the color filter layer by causing fine particles to project on the surface of the color filter layer by the pressure of a fluid.   The method for producing a color filter according to claim 2, wherein the fine particles are projected onto the surface of the color filter layer by ejecting the fine particles and the fluid from a two-fluid shower.   4. The color filter according to claim 3, wherein the projection of the fine particles due to the pressure of the fluid on the surface of the color filter layer is performed by ejecting a mixture of the fine particles and a liquid from the two-fluid shower. Production method.   The method for manufacturing a color filter according to claim 2, wherein the fine particles are projected onto the surface of the color filter layer by ejecting the fine particles and the liquid separately.   The method for producing a color filter according to claim 1, wherein the fine particles have a particle size of 0.05 μm to 10 μm.   The fine particles are alumina, zirconia, silicon oxide, silicon nitride, silicon carbide, magnesium oxide, titanium oxide, zinc oxide, indium oxide, tin oxide, acrylic resin, phenol resin, epoxy resin, polyimide resin, polyurethane resin, melamine resin, And a method for producing a color filter according to any one of claims 1 to 6, wherein the color filter is selected from the group consisting of a mixture of two or more thereof.   The color according to any one of claims 1 to 4, 6, and 7, wherein the fine particles are accelerated together with a liquid having a pressure of 0.05 MPa to 5 MPa and projected onto a surface layer portion of the color filter layer. The manufacturing method of the filter.   The color filter produced by the manufacturing method of the color filter in any one of Claims 1-8.

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