JP2008201983A - PsiCOLOR FILTER POLISHING SLURRY COMPOSITION - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter polishing slurry composition which maintains the stability of color filter materials, enhances the reliability of color filters and ensures good production capacity and yield. <P>SOLUTION: The color filter polishing slurry composition comprises a polishing agent, a buffer solution and additives. The polishing agent is selected from among the group consisting of carbon compounds, diamond and their mixture. The buffer solution is used to adjust the pH value. The additives are used to stabilize the slurry composition and to improve the polishing effect. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing slurry (slurry slurry), and more particularly to a polishing liquid (slurry) composition for polishing a color filter.

  With the great progress of computer performance and the advanced development of internet multimedia technology, the transmission of image data has been already converted from analog to digital transmission to adapt to the modern lifestyle. In addition, the volume of video or image devices is becoming lighter and thinner day by day. Although conventional cathode ray tubes (CRTs) still have advantages, due to the internal electronic space structure, there is a problem that the display volume is huge and occupies space, and radiation damages the eyes during display. Therefore, flat panel displays, such as liquid crystal displays (LCDs), organic light emitting displays (OLEDs), or plasma display panels (Plasma Display Panels = PDPs), which are adapted to the development of photoelectric technology and semiconductor manufacturing technology, are already available. It has become the mainstream of display products.

  Currently, liquid crystal displays are all developed in the direction of full color, large size, and high resolution, and the liquid crystal display must be equipped with a color filter (Color Filter = CF) to give the liquid crystal display a color image function. . The color filter not only affects the color characteristics of the display panel, but also affects the performance of the panel, such as contrast, brightness, and surface reflection.

  The liquid crystal display can display a color image mainly depending on the color filter, and a three-color pigment photoresist of red, green and blue is applied on the color filter. The backlight source forms a grayscale light source through the control of the liquid crystal and the driving IC, and this light source further forms red, green and blue light through the color filter, and finally mixes in the human eyeball A color image is formed. Color filters are the main components of thin-film transistor (TFT) panels, and from the viewpoint of material costs, color filters are components with the largest panel cost ratio, including backlight modules and drive ICs. Higher than.

  FIG. 1 is a structural explanatory view showing a known color filter. As shown in FIG. 1, the basic structure of the color filter is a glass substrate (Glass Substrate) 100, a black matrix (Black Matrix) 102, color layers (Color Layer) 104a to 104c, and a protective layer (Over Coat). 106 and indium tin oxide (ITO) transparent conductive film 108. Currently, the thickness of the glass substrate 100 has already been reduced to 0.63 mm or 0.55 mm, reducing the weight of the large LCD module. The black matrix 102 mainly partitions the three colors of the color layers 104a to 104c and is a key point for improving the color contrast. The black matrix 102 is generally required to have low reflection, and the less the reflection, the better, and the better the color expression. The black matrix 102 has two types of materials, chromium and resin.

  There are more than 10 types of color filter manufacturing methods, and commonly used techniques include pigment dispersion method, dyeing method, printing method, and electrodeposition method. Among them, the pigment dispersion method has high reliability and high analysis degree. Widely adopted because it has good characteristics such as high temperature resistance.

  The basic composition of the photoresist ink (also called color photoresist) used to produce a color filter by the pigment dispersion method is not only a simple substance such as a pigment, a dispersant, an additive, a bonding resin, a reactive diluent, It contains substances such as photopolymerization initiators and solvents. Photoresist ink, which is a coloring material for the three primary colors of red, green, and blue, is generally a negative photo-resist for alkaline development. Currently, the main production method of color filters is the pigment dispersion method, and the materials used are mainly pigment compounds, and the structure of the pigment includes diazo, phthalocyanine organic pigments (phthalocyanine organic pigments). pigments) and various mixed polycyclic systems, using different mixtures taking into account different properties, product functions and processes.

  The color filter manufacturing process of the pigment dispersion method includes a black matrix process, an RGB process, and a post process. First, in the black matrix process, a chromium oxide / chromium low-reflection two-layer film is formed by sputtering on an alkali-free boron glass substrate coated with a nitrogen oxide silicon protective film and used as a substrate. This low-reflection two-layer film is called a metal black layer. Next, a positive photoresist is formed on the light shielding metal layer by a spin coating method. Further, the black matrix photomask pattern is irradiated with ultraviolet rays and exposed to develop the photoresist, and then the light shielding metal layer is etched to form a black matrix pattern.

  The RGB process is performed after the black matrix pattern is formed. The so-called RGB process is a process of forming R, G, and B three-color patterns in the openings. First, a red (R) color photoresist is applied by spin coating, exposed through an R pattern photomask, and irradiated with UV light having a wavelength of less than 248 nm, and an unexposed portion is removed using an alkaline developer. By doing so, an R pattern for the first color is formed, and post baking is performed at 200 ° C. or higher to provide chemical resistance to the pattern. Next, the green (G) color photoresist or the blue (B) color photoresist is replaced, and the same process as that for forming the R pattern is repeated to form the G pattern and the B pattern. Each pattern is partitioned by a black matrix, and this function increases the contrast during display and prevents the generation of miscellaneous color light. Finally, a post process is performed to form an ITO transparent electrode layer that is a corresponding electrode of the TFT array substrate, thereby completing the production of the color filter.

  In order to obtain optical characteristics such as matching reflectance and spectral transmittance of the color filter surface and to obtain a good visual effect, the color filter after completing the RGB process must be flattened on the surface (generally, Then, the ITO transparent electrode layer is laminated. As shown in FIG. 2, after the step of forming the R, G, B three color patterns, each pattern is partitioned by the black matrix BM. Based on different standard requirements, the height after polishing, that is, the position of R1, R2, B1, B2, G1, G2 must be less than 5000 mm. The positions of the valley bottoms R, G, B must be controlled so that the descent amount after polishing (referred to as RGB loss) is 500 mm or less.

  However, when the color filter is flattened by the chemical mechanical polishing method, the compound contained in the used slurry (slurry slurry) may change the chemical properties of the pigment in the color filter during the polishing process. There is room for.

  Accordingly, an object of the present invention is to reduce the possibility of generating an interaction with a color filter material, for example, a resin / dye and a dispersant, when the polishing liquid is composed in the polishing process. An object of the present invention is to provide a color filter polishing liquid composition having a high production capacity and a high yield by improving the reliability of the produced color filter by maintaining the stability.

  When flattening the color filter in the chemical mechanical polishing method, the mechanical cutting action is further advanced and this invention uses abrasive particles that are harder than ordinary oxides to improve the cutting force and improve the chemical action. It is achieved to reduce the influence of.

  The color filter polishing composition provided by the present invention comprises at least an abrasive, a buffer solution, and an additive. The abrasive is selected from a carbon compound, diamond, a nitrogen compound, or a mixture thereof.

  The carbon compound in the polishing composition is selected from the group consisting of silicon carbide, boron carbide, vanadium carbide, titanium carbide, tungsten carbide, zirconium carbide, or a mixture thereof.

  The nitrogen compound in the polishing composition is selected from the group consisting of aluminum nitride, boron nitride, carbon nitride, titanium nitride, tantalum nitride, or a mixture thereof.

  The primary particle size distribution of the abrasive particles in the polishing composition is less than 1.0 micrometer and the main particle size is 10 nanometers to 1 micrometer, preferably 30 to 800 nanometers. The content of the abrasive in the chemical polishing composition is 0.5 to 45 weight percent, preferably 2 to 25 weight percent.

  The buffer solution is used to adjust the pH value and is a solution that buffers the pH value. The buffer solution is selected from the group consisting of inorganic acids, organic acids, bases and mixtures or salts thereof, and the content in the color filter polishing composition is 0.01 to 0.05 weight percent. The choice of the buffer solution depends on the abrasive material.If an inorganic acid is selected, it can be sulfuric acid, hydrochloric acid, nitric acid, etc., and the organic acid can be glycine, formic acid, acetic acid, propionic acid, malic acid, It can be selected from the group consisting of citric acid / succinic acid and mixtures thereof. In addition, the selected salts can further include organic or inorganic salts of sodium, potassium, calcium, and iron. The base can be sodium hydroxide or potassium hydroxide.

  A surfactant is included in the additive of the polishing composition, and the surfactant is used to correct the interfacial potential of the polishing composition, and the degree to which the particles are dispersed and suspended under a specific pH value. Used to enhance and stabilize the polishing composition. The surfactant can be selected from one of polycarboxylic acids, ammonium salts of polycarboxylic acids, alkaline salts, aliphatic polymers or mixtures thereof. The content of the surfactant in the color filter polishing composition is 0.3 to 1.0 weight percent. The molecular weight of the aliphatic polymer is 1000 to 5000 daltons.

  Depending on the abrasive, the additive of the polishing composition can be selected from N-methylpyrrolidone, butyrolactone, methacrylamine, N-vinylpyrrolidone, or a composition mixed at a constant ratio thereof, or It can be selected from N, N'-methylenebisacrylamine, polyethylene glycol, dimethacrylate, methoxypolyethylene glycol monomethacrylate, or a composition mixed by a certain ratio thereof, and improves the polishing rate and the polishing quality.

<Action>
The polishing liquid composition of the present invention is applied to a color filter, and particularly for a color filter, its polishing rate is superior to that of a conventional polishing liquid.

  In addition, since the color filter polishing composition of the present invention adds a special abrasive, it can reduce the occurrence of chemical reaction with the photoresist material during the polishing process, and the color filter is excessively polished. Thus, unnecessary erosion problems can be avoided. In this way, the pattern reliability of the color filter can be improved, and an optical element that is precise, accurate in dimensions, excellent in optical properties, and high in reliability can be manufactured.

  As can be seen from the experimental results described below, the color filter polishing composition of the present invention can reduce the occurrence of chemical reaction with the photoresist material during the polishing process due to the characteristics of the abrasive and the components. Since it is possible to avoid an unexpected influence on the resist material, the service life of the thin film transistor liquid crystal display (TFT LCD) panel can be extended. At the same time, the color filter can be over-polished to avoid unnecessary erosion problems. It is possible to manufacture an optical element that is precise and has precise dimensions, excellent optical characteristics, and high reliability.

  The color filter polishing liquid composition of the present invention is capable of maintaining the stability and activity of the polishing liquid over a long period of time, has a high reliability of the produced color filter pattern, and has excellent production capacity and yield. Yes.

The best mode for carrying out the present invention will be described below with reference to the drawings.
The color filter polishing composition of the present invention refers to a chemical auxiliary agent that assists in polishing a color filter. Such a color filter polishing liquid composition can be used alone as a polishing liquid in the color filter polishing step, and can also be used in combination with other color filter polishing liquids.

  The color filter polishing composition of this invention contains at least one type or one or more types of abrasives, and the abrasives are selected from carbon compounds, diamonds, nitrogen compounds, or mixtures thereof. If the abrasive is a carbon compound, it is selected from the group consisting of silicon carbide, boron carbide, vanadium carbide, tungsten carbide, zirconium carbide or mixtures thereof. The abrasive can be selected from diamond. If the aforementioned abrasive is a nitrogen compound, it is selected from the group consisting of boron nitride, carbon nitride, aluminum nitride, titanium nitride, tantalum nitride, or a mixture thereof. The particle diameter is 50 nanometers to 5 micrometers, and the abrasive of the present invention has a concentration in the color filter polishing composition of 0.5 to 45 weight percent, preferably 2 to 25 weight percent abrasive. including.

  In producing a color filter, since the demand for the purity of the abrasive is strict, it is desirable that the abrasive is of high purity. The so-called “high purity” refers to the total miscellaneous content of the source (for example, raw material) The purpose is to reduce the potential contamination of the polishing liquid to the color filter and avoid affecting its performance and service life. is there.

  The abrasive is preferably made into an aqueous dispersion using an aqueous medium (for example, deionized water) in combination. Such an aqueous dispersion of an abrasive can be produced using known techniques. For example, the abrasive is slowly added to a suitable medium and known to this mixture. Dispersion is completed by high-speed shearing. Then, by adjusting the pH value of the dispersion liquid, the dispersed polishing liquid is provided with good stability.

  The color filter polishing composition of this invention contains at least one buffer solution. This buffer solution is used to adjust the pH value of the color filter polishing composition. This buffer solution is selected from the group consisting of inorganic acids, organic acids, bases and mixtures or salts thereof. The selection of the buffer solution depends on the abrasive material. Examples of the inorganic acid include sulfuric acid, hydrochloric acid, and nitric acid. The organic acid can be selected from the group consisting of glycine, formic acid, acetic acid, malic acid, citric acid, succinic acid and mixtures thereof. Moreover, organic salts, inorganic salts, or mixtures thereof, such as potassium nitrate, potassium iodide, and potassium carbonate, can be added to the organic acid. The buffer solution further contains sodium, calcium, and iron ions. The base can be sodium hydroxide, potassium hydroxide, or the like.

  The content of the buffer solution in the color filter polishing composition is, for example, 0.01 to 0.05 weight percent. In addition, the color filter polishing liquid composition is preferably adjusted to a pH value of 2 to 10 using a buffer solution, and more preferably to a pH value of 5 to 9.

  In addition to the above-described compositions disclosed by the present invention, other polishing liquid additives may be used in combination with the color filter polishing liquid composition of the present invention.

  The color filter polishing liquid composition of the present invention contains at least one additive, which is used for the polishing liquid to stabilize the particle size growth of the abrasive under acidic conditions. , To stabilize the surface charge of the abrasive particles and maintain the long-term stability of the polishing liquid under acidic conditions.

  The surfactant can be selected from one of polycarboxylic acid, ammonium salt of polycarboxylic acid, aliphatic polymer or a mixture thereof. The surfactant is 0.3 to 1.0 weight percent in the color filter polishing composition. The molecular weight of the aliphatic polymer is, for example, 1000 to 5000 daltons.

  The additive is selected from N-methyl-pyrolidone, butyrolactone, methcrylaminde, N-vinyl pyrolidone and a composition mixed at a certain ratio. Or, methacrylamine, N, N'-methylenebisacrylamine (N, N'-methylene bisacrylamine), polyethylene glycol (diethylene glycol), dimethacrylate, methoxy polyethylene glycol monomethacrylate (methoxy polyethylene glycol monomethacrylate) ) And a composition mixed at a constant ratio.

  In the color filter polishing method of the present invention, the color filter can be polished by a relative motion between the color filter and the polishing pad after the polishing composition is supplied onto the surface of the color filter mounted on the polishing table. . In the polishing process, a polishing liquid is continuously supplied by a pump between the surface of the polishing pad and the surface to be polished of the substrate. After the polishing is completed, the object to be polished is washed.

  The color filter polishing liquid composition of the present invention adds a special polishing component, and this polishing component generates a chemical reaction with the photoresist material of the color filter unit in the polishing process, affecting the optical characteristics of the color filter. In addition, since the color filter can be prevented from being excessively polished, it does not cause unnecessary erosion problems. In this way, it is possible to improve the reliability of the color filter, and to manufacture an optical element that is precise, accurate in dimensions, excellent in optical characteristics, and highly reliable.

  Hereinafter, the present invention will be described with reference to experimental examples 1 to 9, but the present invention is not limited to the following experimental examples. Table 1 shows the polishing liquid compositions of Experimental Examples 1 to 9. After the polishing liquid compositions of Experimental Example 1 to Experimental Example 9 were prepared, the already prepared color filter samples were polished. The results of Experimental Example 1 to Experimental Example 9 are shown in Table 2.

First, you must measure and record the peak / bottom height of the three RGB colors, re-measure after polishing to demonstrate the effect of the polishing liquid, and control the RGB loss to 500mm or less. Under this assumption, the removal rate of the polishing liquid must be examined. The experimental conditions of this experiment are as follows:
Polisher down pressure = 0.03 psi or 0.08 psi
Rotation speed of polishing table = 20rpm
Polishing time = 20sec
Polishing fluid flow rate = 60ml / min
Then, the polishing rate is calculated by dividing the difference in thin film thickness before and after polishing by the polishing time. Among them, the thin film thickness is obtained using KLA Tencor P15 profiler. Δh _R , Δh _G , and Δh _B represent average polishing removal amounts of the R, G, and B color photoresists, respectively. Next, Experimental Example 1 to Experimental Example 9 and test results will be described.

<Experimental Examples 1-3>
As shown in Table 1 and Table 2: In Experimental Examples 1 to 3, 0.5 wt% diamond (particle size: about 50 nm) was used as an abrasive, and polishing liquids (pH values 5.0, 7.0, 9.0, respectively) were prepared. Although the average removal amount of △ h _R / △ h _G / △ h _{B for} 20 seconds under a down force of 0.05 psi is low, Experimental Examples 1 and 3 are necessary for color filter manufacturing process production Can satisfy anything. FIG. 3 shows a scanning electron microscope (SEM) photograph of diamond abrasive particles (0.50 μm). 4A and 4B are explanatory views showing a color filter SEM photograph after polishing, which is a color filter polishing liquid composition using diamond polishing particles (50 nm) as polishing particles. As shown in FIGS. 4A and 4B, the polished color filter has no scratches on the surface, and has extremely good flatness and extremely low surface roughness.

<Experimental example 4>
As shown in Table 1 and Table 2: In Experimental Example 4, a 5 wt% diamond (particle size of about 50 nm) was used as an abrasive and a polishing liquid (pH = 7.0) was prepared, and a down force of 0.08 psi (down force) ), The average Δh _R / Δh _G / Δh _B polishing removal amount for 20 seconds is a better result than that of Experimental Example 2.

<Experimental example 5>
As shown in Tables 1 and 2: Experimental Example 5 uses 10 wt% diamond (particle size of about 100 nm) as an abrasive, and the production and shape of this diamond abrasive is different from Experimental Examples 1-4. A polishing solution (pH = 4.3) was prepared, and under a down force of 0.05 psi, 20 seconds average △ h _R / △ h _G / △ h _B polishing removal amount was produced in the color filter manufacturing process You can meet what you need. Compared with Experimental Example 1, the result is even better.

<Experimental Examples 6-8>
As shown in Table 1 and Table 2: In Experimental Examples 6 to 8, 20 wt% silicon carbide (particle size: about 0.65 μm) was used as an abrasive, and polishing liquids (pH values 5.0, 7.0, 9.0, respectively) were prepared. Under a down force of 0.05 psi, the average Δh _R / Δh _G / Δh _B polishing removal for 20 seconds can meet what is needed for color filter manufacturing process production. FIG. 5 shows an SEM photograph of silicon carbide abrasive particles (0.65 μm). The shape of the abrasive particles is a sharp polygon and has a very good cutting force. FIG. 6 shows an optical microscope (OM) photograph of the color filter after polishing, and is a color filter polishing liquid composition using silicon carbide (0.65 μm) as polishing particles. As shown in FIG. 6, the polished color filter is free from scratches on the surface, and has extremely good flatness.

<Experimental Example 9>
As shown in Tables 1 and 2: Experimental Example 9 is an abrasive of 10 wt% cubic boron nitride (CBN = Cubic Boron Nitride particle size: about 0.65 μm), and the shape of the abrasive particles is a sharp polygon. And has a very good cutting force. Prepare polishing liquid (pH value = 5.0), and under average down pressure of 0.03psi, 20 seconds average △ h _R / △ h _G / △ h _B polishing removal amount is color filter manufacturing process It can satisfy what is necessary for production.

  As described above, the present invention has been disclosed in the best mode. However, the present invention is not intended to limit the present invention and is within the scope of the technical idea of the present invention so that those skilled in the art can easily understand. Since appropriate changes and modifications can be naturally made, the scope of protection of the patent right must be determined on the basis of the scope of claims and an area equivalent thereto.

It is structure explanatory drawing which shows a well-known color filter. It is structure explanatory drawing which shows a well-known color filter. It is explanatory drawing which shows the scanning electron microscope (SEM) photograph of a diamond abrasive particle (0.50 micrometer). It is explanatory drawing which shows the SEM photograph of the color filter after grinding | polishing, and uses the color filter polishing liquid composition which uses a diamond (50 nm) as an abrasive particle. It is explanatory drawing which shows the SEM photograph of the color filter after grinding | polishing, and uses the color filter polishing liquid composition which uses a diamond (50 nm) as an abrasive particle. It is explanatory drawing which shows the SEM photograph of a silicon carbide abrasive particle (0.65 micrometer). It is explanatory drawing which shows the optical (OM) photograph of the color filter after grinding | polishing, and uses the color filter polishing liquid composition which uses silicon carbide (0.65 micrometer) as an abrasive particle.

Explanation of symbols

100 Glass Substrate
102, BM Black Matrix
104a-104c Color Layer (Color Layer)
106 Protective layer (Over Coat)
108 Transparent conductive layer R, R1, R2, B, B1, B2, G, G1, G2 Position

Claims (18)

Color filter polishing liquid (slurry) composition comprising:
An abrasive, wherein the abrasive is selected from the group consisting of carbon compounds, diamonds, nitrogen compounds or mixtures thereof;
a buffer solution used to adjust the pH value;
A color filter polishing liquid composition comprising: an additive for correcting the polishing liquid (slurry) composition to an interface potential having a specific pH value.  The color filter polishing composition according to claim 1, wherein the carbon compound is selected from the group consisting of silicon carbide, boron carbide, vanadium carbide, titanium carbide, tungsten carbide, zirconium carbide, or a mixture thereof.  The color filter polishing composition according to claim 1, wherein the nitrogen compound is selected from the group consisting of aluminum nitride, boron nitride, carbon nitride, titanium nitride, tantalum nitride, or a mixture thereof.  The color filter polishing composition according to claim 1, wherein the abrasive contains 10 nanometers to 1 micrometer as a primary particle size in the chemical polishing composition.  The color filter polishing composition according to claim 1, wherein the abrasive contains 50 nanometers to 800 nanometers as a primary particle size in the chemical polishing composition.  The color filter polishing composition according to claim 1, wherein the abrasive contains 0.5 to 45 weight percent in the chemical polishing composition.  The color filter polishing composition according to claim 1, wherein the polishing material contains 2 to 25 weight percent in the chemical polishing composition.  The color filter polishing composition according to claim 1, wherein the pH value of the color filter polishing composition is 2 to 10.  The color filter polishing composition according to claim 1, wherein the pH value of the color filter polishing composition is 5-9.  The color filter polishing composition according to claim 1, wherein the buffer solution is selected from the group consisting of inorganic acids, organic acids, bases and mixtures or salts thereof.  The color filter polishing composition according to claim 10, wherein the inorganic acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid and mixtures thereof.  The color filter polishing composition according to claim 10, wherein the organic acid is selected from the group consisting of glycine, formic acid, acetic acid, propionic acid, malic acid, citric acid, succinic acid and mixtures thereof.  The color filter polishing composition according to claim 10, wherein the salt contains an organic or inorganic salt of sodium, potassium, calcium, or iron.  The color filter polishing composition according to claim 1, wherein the additive contains a surfactant.  The color filter polishing composition according to claim 14, wherein the content of the surfactant is 0.3 to 1.0 weight percent.  The color filter polishing liquid composition according to claim 1, wherein the surfactant can be selected from one of polycarboxylic acids, ammonium salts of polycarboxylic acids, alkaline salts, aliphatic polymers or mixtures thereof. object.  The color filter polishing liquid composition according to claim 16, wherein the aliphatic polymer has a molecular weight of 1000 to 5000 Daltons.  The additive is N-methylpyrrolidone, butyrolactone, methacrylamine, N-vinylpyrrolidone, N, N'-methylenebisacrylamine, polyethylene glycol, dimethacrylate, methoxypolyethylene glycol monomethacrylate, or a mixture thereof. The color filter polishing composition according to claim 1, which is selected from one kind.