JP2010014774A - Aqueous dispersion for polishing and polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous dispersion for polishing a color filter, polishing uneven part generated on a color filter in a color filter manufacturing process while attaining high polishing speed and high flattening characteristic, and to provide a color filter polishing method using the aqueous dispersion for polishing a color filter. <P>SOLUTION: This aqueous dispersion for polishing a color filter includes: (A) inorganic particles having a mean primary particle diameter of 10-100 nm and a means secondary particle diameter of 30-300 nm, and (B) water soluble polymer having a molecular weight of 5,000-5,000,000. Further it may include (C) organic particles. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to flattening of color filters used in flat panel displays, color image pickup tube elements, color sensors, and the like, and more particularly to an aqueous dispersion for polishing and a polishing method useful for flattening color filters.

  In recent years, the use of flat panel displays such as liquid crystal displays, plasma displays, and organic EL displays as display devices such as personal computers, televisions, and mobile phones has spread. Many flat panel displays perform color display, and a liquid crystal display or an organic EL display generally uses a color filter to perform color display. The color filter is formed by forming a pattern of RGB three primary colors on a glass or plastic substrate, and color display can be performed by passing light from a backlight. Color filters are also used for color imaging tube elements, color sensors, and the like.

A color filter encloses a liquid crystal together with a glass substrate through a spacer and is combined with a polarizing plate or a backlight module to form a liquid crystal display. When manufacturing such a liquid crystal display, if there are minute foreign objects or protrusions on the color filter, the spacer cannot make the gap (cell gap) between the color filter and the glass substrate uniform, and an appropriate voltage must be applied. It becomes difficult to control the orientation of the liquid crystal by application. For this reason, methods such as removal by a laser or removal by a polishing film have been performed on foreign matters and protrusions on the color filter (see, for example, Patent Documents 1 to 3). The color filter is manufactured using a photoresist method in which a pigment is dispersed, a printing method, or the like. In any of the methods, if the surface of the color filter is not smooth, the color reproducibility, contrast, brightness, and other performances are degraded. Therefore, a method of flattening the color filter using a suspension of alumina or the like has been proposed (patent) Reference 4).
However, in all cases, the surface smoothness of the color filter is not sufficient to obtain high-quality color reproducibility, contrast, luminance, and the like, and furthermore, sufficient polishing speed and surface smoothness cannot be achieved at the same time.
JP-A-8-25205 JP-A-9-57634 JP 2001-62696 A Japanese Patent Laid-Open No. 7-151911

  The present invention relates to a color filter polishing aqueous dispersion capable of polishing unevenness generated on a color filter in a color filter manufacturing process while achieving both a high polishing rate and a high flattening characteristic, and the color filter polishing aqueous system. It is an object of the present invention to provide a color filter polishing method using a dispersion.

  The present inventors have a color comprising (A) inorganic particles having an average primary particle diameter of 10 to 100 nm and an average secondary particle diameter of 30 to 300 nm, and (B) a water-soluble polymer having a molecular weight of 5,000 to 5,000,000. It has been found that the above problems can be solved by using an aqueous dispersion for filter polishing.

  According to the color filter polishing aqueous dispersion, unevenness generated on the color filter in the color filter manufacturing process can be polished while achieving both a high polishing rate and a high leveling property.

The color filter polishing aqueous dispersion according to the present invention includes (A) inorganic particles having an average primary particle diameter of 10 to 100 nm and an average secondary particle diameter of 30 to 300 nm, and (B) a molecular weight of 5,000 to 5,000,000. And a water-soluble polymer.
The color filter polishing aqueous dispersion according to the present invention may further contain (C) organic particles.
In the color filter polishing aqueous dispersion according to the present invention, the component (A) may be silica.
In the aqueous dispersion for polishing color filters according to the present invention, the average secondary particle size of the component (C) can be smaller than the average average secondary particle size of the component (A).
Hereinafter, preferred embodiments of the present invention will be described in detail.

<(A) Inorganic particles>
Examples of inorganic particles (A) having an average primary particle diameter of 10 to 100 nm and an average secondary particle diameter of 30 to 300 nm used in the present invention include silica, alumina, ceria, talc, aluminum hydroxide, magnesium hydroxide, and carbonic acid. One or more selected from calcium can be used. Preferably, fumed silica synthesized by the fumed method in which silicon chloride or the like reacts with oxygen and hydrogen in the gas phase, silica synthesized by hydrolytic condensation from metal alkoxide, and impurities removed by purification Colloidal silica synthesized by an inorganic colloid method or the like can be used. In particular, colloidal silica synthesized by an inorganic colloid method in which impurities are removed by purification is preferred.

  The average primary particle size of the component (A) used in the present invention is preferably 10 to 100 nm, more preferably 12 to 90 nm, and most preferably 15 to 80 nm. When the average primary particle size is in the above range, a polishing aqueous dispersion having a high polishing rate and excellent flatness can be produced. When the average primary particle size is smaller than the above range, an aqueous dispersion having a sufficiently high polishing rate may not be obtained. On the other hand, when the average primary particle diameter is larger than the above range, the flatness may be deteriorated. In addition, the average primary particle diameter defined by this invention is the value which averaged the diameter of 100 primary particles by direct observation with a transmission electron microscope.

  The average secondary particle size of the component (A) used in the present invention is preferably 30 to 300 nm, more preferably 30 to 250 nm, and most preferably 40 to 200 nm. When the average secondary particle diameter is in the above range, a stable polishing aqueous dispersion in which particles do not settle or separate can be produced. When the average secondary particle diameter is smaller than the above range, an aqueous dispersion having a sufficiently high polishing rate may not be obtained. On the other hand, when the average secondary particle diameter is larger than the above range, the particles may be settled and separated, which is not preferable. The average secondary particle size defined in the present invention is a value measured by a light scattering diffraction method or a dynamic light scattering method.

  The addition amount of the component (A) used in the present invention relative to the total amount of the polishing aqueous dispersion is preferably 0.1 to 10.0%, more preferably 0.5 to 8.0%, still more preferably 1. 0 to 5.0%. If the amount added is less than 0.1%, a sufficient polishing rate cannot be obtained, and if it exceeds 10.0%, the cost increases and the practicality decreases, which is not preferable.

<(B) Water-soluble polymer>
Examples of the water-soluble polymer (B) having a molecular weight of 5,000 to 5,000,000 used in the present invention include polyacrylic acid (PAA) and a salt thereof, polymethacrylic acid and a salt thereof, a copolymer of acrylic acid and methacrylic acid, and Examples thereof include sulfonic acid-containing polymers such as salts thereof, polymaleic acid and salts thereof, polyvinyl alcohol, polyvinyl pyrrolidone (PVP), polyacrylamide, and polyisoprene sulfonic acid, and salts thereof, and hydroxyl group-containing polymers such as hydroxyethyl acrylate and polyvinyl alcohol. be able to. These water-soluble polymers have a weight average molecular weight (Mw) in terms of polyethylene glycol of more than 5,000 and not more than 5,000,000, preferably more than 6,000 and not more than 4,000,000, as measured by aqueous GPC (gel permeation chromatography). More preferably, it is 8000 to 2.5 million. When the weight average molecular weight is in the above range, polishing friction can be reduced and the polished surface can be smoothed. If the weight average molecular weight is smaller than the above lower limit, the polishing friction is increased and the smoothness of the polished surface is deteriorated. In addition, if the weight average molecular weight is too large, the stability of the aqueous dispersion is deteriorated, and the viscosity of the aqueous dispersion is excessively increased, which causes a load on the polishing liquid supply device. There is.

  The amount of the component (B) used in the present invention is 0.01 to 5% as a concentration in the polishing aqueous dispersion. More preferably, it is 0.05-3%, More preferably, it is 0.05-2%. When the addition amount of the component (B) is within the above range, the viscosity of the polishing aqueous dispersion is 1.5 to 100 mPa · s, preferably 1.5 to 50 mPa · s, more preferably 1.5 to 20 mPa · s. s can be adjusted, and better flatness can be obtained. When the added amount of the component (B) is smaller than the above range, it is difficult to make the viscosity of the polishing aqueous dispersion 1.5 mPa · s or more, and the sufficient polishing rate and surface smoothness tend to be lowered. There is not preferable. Further, when the amount of the component (B) exceeds the above range, the viscosity of the polishing aqueous dispersion may exceed 100 Pa · s, and the stability of the polishing aqueous dispersion may be reduced. This is not preferable because the flow of liquid tends to be poor and unevenness in the substrate tends to occur.

<(C) Organic particles>
(C) Organic particles having a particle size smaller than the average secondary particle size of the component (A) include polyvinyl chloride, polystyrene and styrene copolymers, polyacetal, saturated polyester, polyamide, polycarbonate, polyethylene, polypropylene, poly Preferably, polyolefins such as -1-butene and poly-4-methyl-1-pentene, and olefin copolymers, (meth) acrylic resins such as phenoxy resin and polymethyl methacrylate, and acrylic copolymers are used. Can do.
The average secondary particle size of the component (C) used in the present invention is preferably smaller than the average secondary particle size of the component (A), and the average secondary particle size of the component (A) is 50 to 95. % Is more preferable. When the average secondary particle size of the component (C) is larger than the average secondary particle size of the component (A), the polishing rate is lowered, which is not preferable. The average secondary particle diameter of the component (C) can be measured by a light scattering diffraction method or a dynamic light scattering method.

<Other additives>
Organic-inorganic composite particles can also be added to the present invention. The organic-inorganic composite particles are not particularly limited in type and configuration as long as the organic particles and the inorganic particles are integrally formed to such an extent that they are not easily separated during polishing. For example, polycondensation of alkoxysilane, aluminum alkoxide, titanium alkoxide, etc. in the presence of polymer particles such as polystyrene and polymethyl methacrylate, and polycondensation of polysiloxane, polyaluminoxane, polytitanoxane, etc. on at least the surface of the polymer particles The composite particle in which the thing was formed is mentioned. The formed polycondensate may be directly bonded to the functional group of the polymer particles, or may be bonded via a silane coupling agent or the like. Further, silica particles, alumina particles, or the like can be used instead of alkoxysilane or the like. These may be held in entanglement with polysiloxane or the like, or may be chemically bonded to the polymer particles by a functional group such as a hydroxyl group which they have. Furthermore, as the organic-inorganic composite particles, composite particles in which organic particles and inorganic particles having different signs of zeta potential are combined by an electrostatic force in an aqueous dispersion containing these particles may be used. The organic-inorganic composite particles having a particle size smaller than the average secondary particle size of the (A) inorganic abrasive are preferably used. More preferably, inorganic abrasive grains having an average secondary particle diameter of 80% or less can be used. When this average secondary particle diameter is larger than (A) inorganic abrasive grains, the polishing rate is lowered, which is not preferable. This average secondary particle diameter can be measured by a light scattering diffraction method or a dynamic light scattering method.

The zeta potential of organic particles is often negative over the entire pH range or a wide pH range excluding a low pH range. In many cases, the organic particles have a negative zeta potential more reliably when they have a carboxyl group, a sulfonic acid group, or the like. When the organic particle has an amino group or the like, it may have a positive zeta potential in a specific pH range.
On the other hand, the zeta potential of inorganic particles is highly pH-dependent and has an isoelectric point at which the zeta potential is 0, and the sign of the zeta potential is reversed before and after the pH depending on the pH.
Therefore, by mixing specific organic particles and inorganic particles in a pH range in which the zeta potential has an opposite sign, the organic particles and the inorganic particles are combined by electrostatic force to form a composite particle. be able to. In addition, even if the zeta potential has the same sign at the pH at the time of mixing, the pH is changed thereafter, and the zeta potential of one particle, especially the inorganic particle, is reversed, thereby integrating the organic particles and the inorganic particles. It can also be converted.
In this way, the composite particles integrated by electrostatic force are polycondensed with alkoxysilane, aluminum alkoxide, titanium alkoxide, etc. in the presence of the composite particles, so that at least the surface thereof has polysiloxane, polyaluminoxane, polytitanoxane. A polycondensate such as the above may be further formed.

  The polishing aqueous dispersion of the present invention may further contain other components such as a surfactant, a pH adjusting agent, and various additives such as a foam suppressor and an antifoaming agent that reduce foaming of the slurry. As the surfactant used in the present invention, any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant can be used.

  Examples of the anionic surfactant include fatty acid soaps, carboxylates such as alkyl ether carboxylates, sulfonates such as alkylbenzene sulfonates, alkyl naphthalene sulfonates, α-olefin sulfonates, and higher alcohol sulfates. Examples thereof include ester salts, sulfuric acid ester salts such as alkyl ether sulfates, and phosphoric acid ester salts such as alkyl phosphoric acid esters. Examples of the cationic surfactant include aliphatic amine salts and aliphatic ammonium salts. Examples of the nonionic surfactant include ether types such as polyoxyethylene alkyl ether, ether ester types such as glycerol ester polyoxyethylene ether, ester types such as polyethylene glycol fatty acid ester, glycerol ester, and sorbitan ester, Examples include acetylene glycol, ethylene oxide adduct of acetylene glycol, and acetylene alcohol. Also included are silicone surfactants, polyvinyl alcohol, cyclodextrin, polyvinyl methyl ether, and hydroxyethyl cellulose. These surfactants can be used singly or in combination of two or more.

  The content of the surfactant used in the present invention is preferably from 0.005 to 2.0% by weight, more preferably from 0.01 to 1% by weight, particularly preferably 0.02%, based on the total amount of the polishing aqueous dispersion. -0.5 wt% is preferred. If the content of the surfactant is less than 0.005% by weight, the flatness may deteriorate or the polishing performance in the substrate surface may vary. In addition, when the surfactant content is added in excess of 1.0% by weight, the flatness improving effect on the content is reduced, and the aqueous dispersion is liable to foam, so that the handleability is deteriorated. Absent.

  As the pH adjusting agent used in the present invention, an organic acid or an inorganic acid can be used as the acidic substance. Organic acids include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, isoprenesulfonic acid, gluconic acid, lactic acid, citric acid, tartaric acid, malic acid, glycolic acid, malonic acid, formic acid, oxalic acid, succinic acid, fumaric acid, maleic Examples thereof include acid and phthalic acid. As the inorganic acid, nitric acid, sulfuric acid, phosphoric acid and the like can be used. These acids may use only 1 type and can also use 2 or more types together.

Examples of the alkali added to adjust the pH include ethylenediamine, ethanolamine and tetramethylammonium hydroxide as the organic base, and sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide as the inorganic base. Alkali metal hydroxides, ammonia, and the like can be used.
By adjusting the pH of the aqueous dispersion, it is possible to increase the polishing rate, which also affects the dispersibility and stability of the abrasive grains. Therefore, the pH is appropriately adjusted within the range where the abrasive grains can exist stably. It is preferable to set.

<Method for adjusting polishing aqueous dispersion>
In the present invention, (A) inorganic abrasive grains, (B) water-soluble polymer, and other additives as needed are added to and mixed with pure water as needed to prepare a polishing aqueous dispersion, which is then polished as it is. However, it may be prepared as a concentrated product with a reduced amount of pure water and diluted before use to obtain the composition of the present invention. In addition, in order to maintain the stability at the time of storage, it is prepared as two liquids, that is, a dispersion containing at least the component (A) and pure water and a solution or dispersion containing at least the component (B) and pure water. The two liquids can be mixed before use, or the two liquids can be mixed and then diluted with pure water to obtain the composition of the present invention. In this case, after preparing a color filter polishing aqueous dispersion by mixing a plurality of liquids, this may be supplied to a chemical mechanical polishing apparatus, or a plurality of liquids may be supplied individually to a chemical mechanical polishing apparatus. A color filter polishing aqueous dispersion may be formed on the polishing pad.

  The color filter polishing aqueous dispersion can be used for chemical mechanical polishing by removing coarse abrasive grains by filtration if necessary. Preferably, those filtered using a PP (polypropylene) depth type filter having a pore diameter of 10 μm or less are suitably used. Preferably, a filter having a pore size of 5 μm or less can be used.

  The polishing apparatus used in the present invention is not particularly limited, but the color filter is pressed while rotating and, if necessary, swung while supplying the polishing aqueous dispersion to the rotating polishing pad. An apparatus capable of polishing the surface of the substrate can be suitably used.

  Although it does not specifically limit as a polishing pad used for this invention, The polishing pad made from a nonwoven fabric or foamed resin can be used conveniently. Grooves and dot patterns can be formed in a predetermined shape on the surface of the polishing pad as needed for the purpose of improving the supply and discharge properties of the slurry. Further, a polishing pad having a multilayer structure in which a harder or softer layer than the polishing surface is bonded to the back surface (opposite side of the polishing surface) of the polishing pad may be used. The shape of the polishing pad is not particularly limited, and can be appropriately selected according to the polishing apparatus, such as a disk shape, a belt shape, and a roller shape. Further, it is preferable that the surface state during polishing is stable, and the polishing performance can be stabilized by performing surface treatment so-called dressing with a brush or a diamond dresser as necessary.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.
<Creation of evaluation color filter>
After forming a black matrix on a 4-inch glass substrate, a red pigment dispersion resist manufactured by JSR Corporation, Opstar CR series (RED759) was applied using a spin coater, and then pre-baked at 70 ° C. for 3 minutes to form a film. A film having a thickness of 2.5 μm was formed. Then, after cooling to room temperature the substrate, using a high pressure mercury lamp (illuminance 250 W / ^{m 2),} it was exposed with an exposure amount of 200 J / ^{m 2} via a predetermined photomask. After that, using developer CD150CR manufactured by JSR Co., Ltd. as a developer, shower developing at 23 ° C. and developer discharge pressure of 0.3 MPa for 1 minute, washing with ultrapure water, and further post-baking at 200 ° C. for 30 minutes. A color filter having a red color pattern was formed on the substrate. Then, in the same manner as the red pattern, a color dispersion filter (GREEN783, BLUE778) containing a green pigment and a blue pigment is used to form a green and blue pattern and an RGB color pattern (FIG. 1). Got. The surface level difference between the R, G, and B pixels measured using P-10 manufactured by KLA Tencor was about 0.5 μm.

<Preparation of aqueous dispersion containing colloidal silica (A1)>
A flask was charged with 12 parts by weight of ammonia water having a concentration of 25% by weight, 18 parts by weight of ion exchange water, and 170 parts by weight of ethanol, and the temperature was raised to 40 ° C. while stirring at a rotation speed of 180 rpm. After a mixed solution of 25 parts by weight of tetramethoxysilane and 15 parts by weight of ethanol was added dropwise for 30 minutes, stirring was continued for 2 hours while maintaining the temperature at 40 ° C., and then cooled to room temperature. Thereby, an alcohol dispersion of colloidal silica particles was obtained. Subsequently, using a rotary evaporator, the operation of removing alcohol while adding ion-exchanged water was repeated several times while maintaining the temperature of the obtained dispersion at 80 ° C. By this operation, an aqueous dispersion containing 20% by weight of colloidal silica (A1) was prepared.
The average primary particle diameter of 100 particles measured by TEM observation of the colloidal silica particles (A1) contained in this aqueous dispersion is 35 nm, and the average measured by a dynamic light scattering method (LB-550 manufactured by Horiba, Ltd.). The secondary particle size was 80 nm.

<Preparation of aqueous dispersion containing colloidal silica (A2)>
A flask was charged with 24 parts by weight of ammonia water having a concentration of 25% by weight, 6 parts by weight of ion exchange water, and 170 parts by weight of ethanol, and the temperature was raised to 40 ° C. while stirring at a rotation speed of 180 rpm. After a mixed solution of 25 parts by weight of tetramethoxysilane and 15 parts by weight of ethanol was added dropwise for 30 minutes, stirring was continued for 2 hours while maintaining the temperature at 40 ° C., and then cooled to room temperature. Thereby, an alcohol dispersion of colloidal silica particles was obtained. Subsequently, using a rotary evaporator, the operation of removing alcohol while adding ion-exchanged water was repeated several times while maintaining the temperature of the obtained dispersion at 80 ° C. By this operation, an aqueous dispersion containing 20% by weight of colloidal silica (A2) was prepared.
The average primary particle diameter of 100 particles measured by TEM observation of the colloidal silica particles (A2) contained in this aqueous dispersion is 78 nm, and the average measured by a dynamic light scattering method (LB-550 manufactured by Horiba, Ltd.). The secondary particle size was 190 nm.

<Preparation of water dispersion containing organic abrasive grains (C1)>
95 parts of methyl methacrylate, 5 parts of methoxypolyethylene glycol methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “NK ester M-90G”, # 400), azo polymerization initiator (manufactured by Wako Pure Chemical Industries, Ltd., (Product name “V50”) 2 parts, 4 parts ammonium dodecylbenzenesulfonate and 400 parts ion-exchanged water were put into a 2 liter flask, heated to 70 ° C. with stirring in a nitrogen gas atmosphere, and 6 hours Polymerized. As a result, an aqueous dispersion containing 20% by weight of polymethyl methacrylate-based particles (D1) having a polyethylene glycol chain and an average particle diameter of 70 nm was obtained.

<Preparation of aqueous dispersion containing organic-inorganic composite abrasive grains (D1)>
The polymethylmethacrylate particles obtained in (3) were diluted with pure water so as to be 10% by weight to obtain an aqueous dispersion. 100 parts of the obtained aqueous dispersion was put into a 2 liter flask, 1 part of methyltrimethoxysilane was added, and the mixture was stirred at 40 ° C. for 2 hours. Thereafter, the pH was adjusted to 2 with nitric acid to obtain an organic abrasive water dispersion (a). Further, the pH of an aqueous dispersion containing 10% by weight of colloidal silica (manufactured by Nissan Chemical Co., Ltd., “Snowtex”) was adjusted to 8 with potassium hydroxide to obtain colloidal silica (b). The zeta potential of the polymethyl methacrylate-based particles contained in the organic abrasive water dispersion (a) was +17 mV, and the zeta potential of the silica particles contained in the colloidal silica (b) was −40 mV.
Thereafter, 50 parts of aqueous dispersion (b) is gradually added to 100 parts of (a) over 2 hours, mixed, stirred for 2 hours, and water dispersion containing particles having silica particles attached to polymethyl methacrylate particles. Got the body. Next, 2 parts of vinyltriethoxysilane is added to the aqueous dispersion and stirred for 1 hour, then 1 part of tetraethoxysilane is added, the temperature is raised to 60 ° C., and stirring is continued for 3 hours, followed by cooling. As a result, an aqueous dispersion containing composite particles was obtained. The average particle size of the composite particles was 120 nm, and an aqueous dispersion containing organic-inorganic composite abrasive grains (D1) having silica particles attached to 80% of the surface of the polymethyl methacrylate-based particles was obtained.

<Preparation of water-soluble polymer (B1) aqueous solution>
A 500 mL flask equipped with a reflux condenser was charged with 60 g of degassed N-vinyl-2-pyrrolidone and 240 g of distilled water. This was heated to 60 ° C. with stirring in a nitrogen stream, and 0.3 g of a 10 wt% aqueous sodium sulfite solution and 0.3 g of a 10 wt% aqueous t-butyl hydroperoxide solution were added. After stirring at 60 ° C. for 3 hours, 1.8 g of a 10 wt% aqueous sodium sulfite solution and 1.2 g of a 10 wt% aqueous t-butyl hydroperoxide solution were added, and stirring was further continued for 3 hours. A 20% by weight aqueous solution of polyvinylpyrrolidone (B1) was obtained.
In addition, about the polyvinylpyrrolidone (B1) prepared here, polyethylene glycol measured by water-based gel permeation chromatography using 0.1 mol / L NaCl aqueous solution / acetonitrile = 80/20 (vol / vol) as an eluent. The converted weight average molecular weight (Mw) was 1,000,000. In addition, the K value obtained by the Fikenscher method was 95.

<Preparation of water-soluble polymer (B2) aqueous solution>
A 1000 mL flask equipped with a reflux condenser was charged with 350 g of distilled water and 150 g of a 3 wt% ammonium persulfate aqueous solution, and the temperature was raised to 80 ° C. while stirring in a nitrogen atmosphere. Next, 60 g of acrylic acid monomer was added dropwise in 60 minutes. After completion of dropping of polyacrylic acid, 40 g of a 3% by weight aqueous ammonium persulfate solution was added, and stirring was further continued at 80 ° C. for 2 hours. The reaction mixture was diluted with distilled water to obtain a 5% by weight aqueous solution of polyacrylic acid (B2).
The weight average molecular weight (Mw) in terms of polyethylene glycol measured by aqueous GPC of the obtained polyacrylic acid was 1,200,000.

<Adjustment of aqueous dispersion for polishing color filter>
A predetermined amount of an aqueous dispersion containing colloidal silica particles (A1) prepared in (1) is charged into a polyethylene bottle with a predetermined amount of 1 liter of pure water so that each component has the content shown in Table 1. Added. After stirring and mixing, (B1) polyvinylpyrrolidone prepared in (5) was added so as to have the content shown in Table 1, and sufficiently stirred. Then, it filtered with the filter of 5 micrometers of hole diameters, and obtained the aqueous dispersion for grinding | polishing of Examples 1 and 2.

  Pure water was put into a polyethylene bottle having a predetermined volume of 1 liter so that each component had a content shown in Table 1, and a predetermined amount of colloidal silica particles (A1) prepared in (1) was added. After stirring and mixing, a predetermined amount of (B2) polyacrylic acid was added and mixed sufficiently with stirring so as to achieve the contents shown in Table 1. Then, it filtered with the filter of 5 micrometers of hole diameters, and obtained the aqueous dispersion for grinding | polishing of Example 3.

  Colloidal silica particles (A1) prepared in (1) and (3) were prepared by putting pure water into a polyethylene bottle having a predetermined volume of 1 liter so that each component had the contents shown in Table 1. A predetermined amount of organic particles (C1) was added. After sufficiently stirring and mixing, a predetermined amount of (B1) polyvinyl pyrrolidone or (B2) polyacrylic acid was added and mixed sufficiently with stirring so as to achieve the contents shown in Table 1. Then, it filtered with the filter of 5 micrometers of hole diameters, and obtained the aqueous dispersion for grinding | polishing of Examples 4-6.

  A predetermined amount of an aqueous dispersion containing colloidal silica particles (A2) prepared in (2) is charged in a predetermined amount of 1 liter of polyethylene bottle so that each component has the content shown in Table 1. After the addition and stirring and mixing, a predetermined amount of (B2) polyacrylic acid was added and sufficiently stirred and mixed. Then, it filtered with the filter of the hole diameter of 5 micrometers, and obtained the aqueous dispersion for grinding | polishing of Example 7.

  An aqueous dispersion containing colloidal silica particles (A2) prepared in (2), in which pure water is introduced into a polyethylene bottle having a predetermined volume of 1 liter so that each component has the content shown in Table 1, and (4 (D1) The organic-inorganic composite particles prepared in (1) were added in a predetermined amount and mixed with stirring. Further, (B2) a predetermined amount of polyacrylic acid was added and sufficiently stirred and mixed. Then, it filtered with the filter of 5 micrometers of hole diameters, and obtained the aqueous dispersion for grinding | polishing of Example 8.

  A predetermined amount of the aqueous dispersion containing the fumed silica particles (A1) prepared in (1) is put into a polyethylene bottle having a capacity of 1 liter, and the compounds shown in Table 1 are contained in respective amounts. And stirred well. Then, it filtered with the filter of the hole diameter of 5 micrometers, and obtained the aqueous dispersion for grinding | polishing of the comparative example 1.

  Using the aqueous dispersion containing the fumed silica particles (A1) prepared in (1) and (3) and the aqueous dispersion containing the organic abrasive grains (A3), the method described in Table 1 was used in the same manner as in Example 1. The polishing aqueous dispersions of Comparative Examples 2 and 3 having the composition were obtained.

<Evaluation of physical properties of polishing aqueous dispersion>
The viscosities of the polishing aqueous dispersions of Examples 1 to 8 and Comparative Examples 1 to 3 were measured using a BL type viscometer. Moreover, solid content was measured using the microwave type solid content measuring machine, respectively. The results are shown in Table 1.

<Color filter polishing>
The color filters for evaluation were polished under the following conditions using the polishing aqueous dispersions of Examples 1 to 8 and Comparative Examples 1 to 3.
Polishing device: Lapmaster LM15
Polishing pad: Politex (Nitta Haas)
Carrier load: 150 hPa
Surface plate rotation speed: 60pm
Polishing time: 5 min
Abrasive supply amount: 100 ml / min

<Surface roughness evaluation>
The surface roughness of the color filters polished with the polishing aqueous dispersions of Examples 1 to 8 and Comparative Examples 1 to 3 was evaluated using an atomic force microscope manufactured by Digital Instruments. The results are shown in Table 1.

<Evaluation of flatness>
The surface steps between the R, G and B pixels of the color filters polished with the polishing aqueous dispersions of Examples 1 to 8 and Comparative Examples 1 to 3 were measured using P-10 manufactured by KLA Tencor. evaluated. Table 1 shows the maximum value of the surface level difference between the pixels as the flatness evaluation result.

<Evaluation of scratch>
The surface of the color filter polished with the polishing aqueous dispersions of Examples 1 to 8 and Comparative Examples 1 to 3 was observed in an area of 100 μm × 100 μm in the dark field using an optical microscope, and the number of scratches was measured. . The results are shown in Table 1.

  From Table 1, it can be seen that the color filter polished using the polishing aqueous dispersion of the present invention has a small surface roughness, excellent flatness, and few scratches. By polishing the color filter using the polishing aqueous dispersion of the present invention, a highly flat color filter excellent in display performance such as color reproducibility, contrast, and luminance can be obtained.

Claims (5)

(A) inorganic particles having an average primary particle diameter of 10 to 100 nm and an average secondary particle diameter of 30 to 300 nm;
(B) A color filter polishing aqueous dispersion comprising a water-soluble polymer having a molecular weight of 5,000 to 5,000,000.   The color filter polishing aqueous dispersion according to claim 1, further comprising (C) organic particles.   The aqueous dispersion for color filter polishing according to claim 1, wherein the component (A) is silica.   The aqueous dispersion for color filter polishing according to any one of claims 2 to 3, wherein the average secondary particle size of the component (C) is smaller than the average secondary particle size of the component (A).   A color filter polishing method using the color filter polishing aqueous dispersion according to any one of claims 1 to 4.