KR20080036351A - Photosensitive resin composition and color filter using the same - Google Patents

Abstract

A photosensitive resin composition is provided to be suitable for the production of ultramicro pixels, to prevent the occurrence of residues, and to produce a color filter for 10 million pixel image sensors. A photosensitive resin composition includes (a) 0.5-20wt% of an acrylic resin containing a carboxyl group and an organic group derived from a pigment, (b) 0.5-20wt% of an acrylic photopolymerizable monomer, (c) 0.1-10wt% of a photopolymerization initiator, and (d) the balance of a solvent. The acrylic resin has a structure represented by the following formula 1, wherein A is a repeating unit of an ethylenically unsaturated monomer that does not contain a carboxyl group, X is O or NH, and PIG is an organic group derived from a pigment.

Description

Photosensitive resin composition and color filter using the same {PHOTOSENSITIVE RESIN COMPOSITION AND COLOR FILTER USING THE SAME}

1 is a schematic diagram of a CMOS image sensor.

Figure 2 is a photograph of the residue of the pixel produced using the composition according to the invention.

Figure 3 is a photograph of the residue of the pixel prepared with a conventional pigment dispersion.

4 is a 1 × 1 μm resolution photograph of a pixel made using the composition according to the invention.

5 is a 1 × 1 μm resolution photograph of a pixel made with a conventional pigment dispersion.

The present invention relates to a photosensitive resin composition, and more particularly, to a photosensitive resin composition and a color using the same, which enables the formation of an ultrafine square pattern required by a high-pixel image sensor by introducing a pigment into the resin in advance. It is about a filter.

An image sensor is made up of millions of photoelectric conversion elements that convert light into an electrical signal depending on the amount of light it receives. These image sensors are used in digital input devices to enable the recording of pre-digital images as digital images, and the demand is growing exponentially for various security devices and digital porters in line with the rapid development of the times. There is a situation.

The image sensor consists of a pixel array, ie a plurality of pixels arranged in a two-dimensional matrix, each pixel comprising light sensing means and transmission and signal output devices. Depending on the transmission and signal output devices, the image sensor is divided into two types: a charge coupled device (CCD) image sensor and a complementary metal oxide semiconductor (hereinafter, referred to as a CMOS) type image sensor.

Referring to the role of the color filter in the image sensor with reference to the schematic diagram of the CMOS image sensor of Figure 1, in order to separate the light from the outside into each R, G, B to transmit to the photodiode corresponding to each pixel It is used.

Until now, research and development on the photosensitive resin composition of the alkaline aqueous solution developing type for the liquid crystal display device color filter has been actively progressed, but research on the photosensitive resin composition for the image sensor color filter has not been actively conducted as in the present patent.

In particular, as part of improving the quality of digital cameras, the size of one side of the pixel has recently decreased from 5 to 3 µm to less than 1 µm.

Patent for image sensor color filter device and process (KR 2002-039125, JP pyeong-10-066094, KR 1998-056215, JP pyeong 7-235655, KR2003-056596, JP-2005-278213, KT2003-002899, JP pyeong 11-354763), but a number of patents for the image sensor color filter composition desired in the present patent, there are Korean Patent Publication 2006-0052171, Japanese Patent Publication 2004-341121 and Japanese Patent Publication No. 7-172032. Among them, Korean Patent Laid-Open Publication No. 2006-0052171 and Japanese Patent Laid-Open Publication No. 2004-341121 are characterized in that a dye is used to manufacture a high-density pixel. However, this method is a method of using a dye instead of a pigment as a pigment, there is a problem in the long-term reliability because one of the characteristics of the dye is light resistance, heat resistance and the like. Although these patents use dyes that ensure heat and light resistance, the methods used in these patents are not reliable because they are data obtained from 1 hour up to 20 hours. Japanese Patent Laid-Open No. 7-172032 suggests the use of a black matrix to prevent color shifting and dislocation between R, G, and B pixels, but this method also requires an additional process for manufacturing the black matrix. In addition, it is practically impossible to manufacture the black matrix in detail, and there is a disadvantage in that the opening ratio becomes small according to the introduction of the black matrix.

All of the above-mentioned methods use a pigment as an R, G, B main dye in addition to the composition, and there is a disadvantage in that the resolution of the pixel has a fundamental problem. That is, it is difficult to manufacture high resolution pixels due to the use of pigments.

In order to solve the above problems, the present invention, instead of using the pigment as a pigment in the preparation of the photosensitive resin composition, by introducing the pigment in advance through the chemical reaction with the resin, it is required in the 10 million pixel image sensor It is an object of the present invention to easily form an ultrafine square pattern.

Another object of the present invention is to increase the process margin in the fabrication process by providing a residue of the non-exposed part, which is a frequent problem when using a pigment dispersion, it is possible to provide an image sensor color filter with an increased yield. To ensure that

The photosensitive resin composition of the present invention for achieving the above object includes an acrylic resin containing an organic group derived from a carboxyl group and a pigment.

The photosensitive resin composition may further comprise (1) 0.5 to 20.0 wt% of an organic group-containing acrylic binder resin derived from a carboxyl group and a pigment; (2) 0.5 to 20.0 wt% of an acrylic photopolymerizable monomer; (3) 0.1 to 10.0 wt% of a photopolymerization initiator; And a solvent as the residual amount.

Still another object of the present invention relates to a color filter for an image sensor in which a pattern is formed by applying, prebaking, exposing, developing and postbaking the photosensitive resin composition of the present invention.

Hereinafter, with reference to the accompanying drawings of the present invention will be described in more detail.

Organic group-containing acrylic resins (hereinafter referred to as 'component (1)') derived from carboxyl groups and pigments used in the present invention are ethylenically unsaturated monomers having one or more carboxyl groups, other ethylenically unsaturated monomers copolymerizable therewith, and carboxyl groups And a repeating unit of a monomer including an organic group derived from a pigment, and may be represented by the following Chemical Formula 1.

The copolymer in which the pigment is introduced is the core of the present invention.

(a) prepared by reaction of an acrylic resin containing a carboxyl group with a pigment (PIG) in the presence of a phase transfer catalyst,

(b) Pigments may be prepared by copolymerization of introduced methacrylic acid with other ethylenically unsaturated monomers.

The molecular weight (Mw) of the said component (1) is 10,000-70,000, More preferably, it is 20,000-50,000.

It is preferable that the usage-amount of the said component (1) is 0.5-20 weight% with respect to the whole composition. If the content of component (1) is less than 0.5% by weight, a problem occurs in which the developer is not developed in the alkaline developer, while in excess of 20% by weight, there is a disadvantage in that the surface roughness is increased due to the lack of crosslinkability.

In particular, the component (1) is the factor which has the greatest influence on the resolution of the pixel in the present invention, and the result is that the resolution of the pixel is clearly changed by acid value and molecular weight.

Examples of the carboxyl group-containing ethylenically unsaturated monomer include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, and the like. The component (1) used in the present invention is a repeating unit of at least one of these monomers. It includes. The repeating unit molar ratio of the carboxyl group-containing ethylenically unsaturated monomer is in the range of 10 to 40 mol%, preferably 20 to 30 mol%.

Moreover, as another ethylenically unsaturated monomer copolymerizable with the said carboxyl group-containing ethylenically unsaturated monomer, For example, styrene, (alpha) -methyl styrene, vinyltoluene, vinyl benzyl methyl ether, methyl acrylate, methyl methacrylate, ethyl acryl Latex, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-hydroxy ethyl acrylate, 2-hydroxy ethyl methacrylate, 2-hydroxy butyl acrylate, 2-hydroxy butyl methacrylate, Unsaturated carboxylic acid esters such as benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, phenyl acrylate and phenyl methacrylate; Unsaturated carboxylic acid amino alkyl esters such as 2-amino ethyl acrylate, 2-amino ethyl methacrylate, 2-dimethyl amino ethyl acrylate and 2-dimethyl amino ethyl methacrylate; Carboxylic acid vinyl esters such as vinyl acetate and vinyl benzoate; Unsaturated carboxylic acid glycidyl esters such as glycidyl acrylate and glycidyl methacrylate; Vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; Unsaturated amides, such as acryl amide and methacryl amide, are mentioned, One or more of these can be selected and used.

Component (1) consisting of such carboxyl group-containing ethylenically unsaturated monomers and other ethylenically unsaturated monomers copolymerizable therewith is specifically, methacrylic acid / methyl methacrylate copolymer, methacrylic acid / benzyl methacrylate copolymer , Methacrylic acid / benzyl methacrylate / styrene copolymer, methacrylic acid / benzyl methacrylate / 2-hydroxy ethyl methacrylate copolymer, methacrylic acid / benzyl methacrylate / styrene / 2-hydroxy It includes the repeating unit of the unsaturated monomer in which the pigment was couple | bonded with ethyl methacrylate copolymer etc.

In addition, the pigment that can be used in the present invention should include a functional group such as a hydroxyl group or an amine group in the molecule and are shown below.

The repeating unit molar ratio of the monomer containing the pigment is in the range of 3 to 20 mol%, preferably 5 to 15 mol% with respect to the copolymer.

The acrylic photopolymerizable monomer (hereinafter referred to as 'component (2)') used in the present invention is a monomer generally used in the photosensitive resin composition, for example, ethylene glycol diacrylate, triethylene glycol diacrylate, 1 , 4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, dipentaerythritol diacrylate, dipentaeryte Lithitol triacrylate, dipentaerythritol pentaacrylate, pentaerythritol hexaacrylate, bisphenol A diacrylate, trimethylolpropane triacrylate, novolac epoxy acrylate, ethylene glycol dimethacrylate, diethylene glycol Dimethacrylate, triethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1, 4- butanediol dimethacrylate, 1, 6- hexanediol dimethacrylate, etc. are mentioned.

It is preferable that the usage-amount of the said component (2) is 0.5-20 weight% with respect to the whole composition. If the content of component (2) is less than 0.5% by weight, there is a problem that the edges of the pattern are not formed cleanly, whereas if the content of component (2) exceeds 20% by weight, there is a disadvantage that the developer is not developed in the alkaline developer.

The photoinitiator (hereinafter referred to as 'component (3)') used in the present invention is a photoinitiator generally used in the photosensitive resin composition, for example, a triazine compound, an acetophenone compound, a benzophenone compound, a tee At least one selected from the group consisting of an oxaanthone compound, a benzoin compound and the like is used.

It is preferable that the usage-amount of the said component (3) is 0.1-10 weight% with respect to the whole composition. If the content of component (3) is less than 0.1% by weight, photopolymerization does not sufficiently occur during exposure in the pattern forming process, whereas if it exceeds 10% by weight, the unreacted initiator remaining after photopolymerization may lower the transmittance.

Specific examples of the triazine-based compound used as the photopolymerization initiator include 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (3 ', 4'-dimethoxy styryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (4'-methoxy naphthyl) -4,6-bis (trichloromethyl ) -s-triazine, 2- (p-methoxy phenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-tril) -4,6-bis (trichloromethyl ) -s-triazine, 2-piphenyl-4,6-bis (trichloromethyl) -s-triazine, bis (trichlorobetayl) -6-styryl-s-triazine, 2- (naphtho 1-yl) -4,6-bis (trichloro methyl) -s-triazine, 2- (4-methoxy naphtho 1-yl) -4,6-bis (trichloro methyl) -s-triazine , 2-4-trichloro methyl (piperonyl) -6-triazine, 2-4-trichloro methyl (4'-methoxy styryl) -6-triazine and the like.

Specific examples of the acetophenone-based compound include 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylproriophenone, pt-butyltrichloroaceto Phenone, pt-butyldichloroacetophenone, benzophenone, 4-chloroacetophenone, 4,4'-dimethylaminobenzophenone, 4,4'-dichlorobenzophenone, 3,3'-dimethyl-2-methoxybenzophenone , 2,2'-dichloro-4-phenoxycetophenone, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino -1- (4-morpholinophenyl) -butan-1-one and the like.

Examples of the benzophenone compounds include benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-phenyl benzophenone, hydroxy benzophenone, acrylated benzophenone, 4,4'-bis (dimethyl amino) benzophenone, and 4,4 '. -Bis (diethyl amino) benzophenone and the like.

Examples of the thioxanthone compounds include thioxanthone, 2-chloro thioxanthone, 2-methyl thioxanthone, isopropyl thioxanthone, 2,4-diethyl thioxanthone, and 2,4-diisopropyl. Thioxanthone, 2-chloro thioxanthone and the like.

The benzoin-based compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyldimethyl ketal and the like.

In addition, a carbazole compound, a diketone compound, a sulfonium borate compound, a diazo compound, a biimidazole compound, and the like can also be used.

Among the triazine compounds, the use of triazine compounds in the photopolymerization initiator is the most suitable for the purpose of the present invention. Among the triazine compounds, the compound having the maximum light absorption wavelength (λmax) in the range of 340 to 380 nm has the greatest influence on the performance of the pixel pattern. The present invention has been completed.

Triazine type photoinitiator more preferable for the objective of this invention is a compound which has the following structure.

o Triazine photopolymerization initiator

Solvents usable in the present invention include ethylene glycol acetate, ethyl cellosolve, propylene glycol methyl ether acetate, ethyl lactate, polyethylene glycol, cyclohexanone, propylene glycol methyl ether, and the like. It can be used or it can mix and use 2 or more types.

In addition, in the present invention, malonic acid, 3-amino-1,2-propanediol, or fluorine-based in order to prevent stains or spots upon coating or to prevent the formation of residue due to leveling control and undevelopment, as necessary. It may further include an additive such as a surfactant.

The preferred content of the additive is 0.1 to 1% by weight.

The method of forming the pattern of the image sensor color filter using the photosensitive resin composition is generally the same as the following process.

Application step

The photosensitive resin composition is apply | coated to the thickness of 0.5-1 micrometer on the wafer for image sensor color filters using a suitable method, such as spin coating and slit coating.

Exposure step

After the coating, light is irradiated to form a pattern necessary for the image sensor color filter. As a light source used for irradiation, I-line light of 365 nm is used.

Developing stage

When the coating layer irradiated with the light is treated with an alkaline developer, an unilluminated portion of the coating layer is dissolved and a pattern necessary for an image color filter is formed.

Repeat

By repeatedly performing the above series of processes according to the required number of R, G, and B colors, an image sensor color filter having a desired pattern can be obtained.

Additional steps

Apart from the above steps, crack resistance, solvent resistance and the like can be further improved by heating the image pattern obtained by development again or curing by active ray irradiation or the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example 1

(1) 12 g of organic group-containing acrylic resin derived from carboxyl group and pigment

    (A) / (B) / (C) = 68/25/7 (mol%), molecular weight (Mw) = 25,000

    (A): benzyl methacrylate

    (B): methacrylic acid

    (C): methacrylate substituted with R-254 pigment

(2) acrylic photopolymerizable monomer

     Dipentaerythritol hexaacrylate (DPHA) 4.1g

(3) photopolymerization initiator

     TPP (made by Ciba Specialty) 0.2g

(4) solvent

     45 g of propylene glycol monomethyl ether acetate

     36.4 g of ethyl ethoxy propionate

(5) additive

     0.1 g of F-475 (fluorine-based surfactant)

Using the above components, a photosensitive resin composition was prepared as follows:

 (1) After dissolving a photoinitiator in a solvent, it stirred at room temperature for 2 hours.

 (2) Organic group-containing acrylic resin derived from carboxyl group and pigment, photopolymerizable

    The monomer was added and stirred at room temperature for 2 hours.

 (3) The surfactant was added and stirred at room temperature for 1 hour.

 (4) Three times of filtration was performed to remove impurities.

The composition prepared by the method described above was coated on a 6-inch wafer using a Mikasachan (1H-DX2) spin coater, and then exposed to light for 180 seconds at 100 ° C., with a reticle engraved with patterns of various sizes. After 250ms exposure with Nikon i-line stepper (NSR i10C), the development was performed for 120 seconds with 2.38% TMAH solution at room temperature. The developed substrate was washed and then dried for 300 seconds on a high temperature plate at 200 ° C. to observe the resolution of the pattern formed by the optical microscope. The cross section of the pattern was measured by scanning electron microscopy (SEM) and the coating thickness was measured by KMAC (ST4000-DLX) equipment, the results are shown in Table 1.

Examples 2-8

The experiment was carried out in the same manner as in Example 1, except that the acrylic resin in which the acid value, molecular weight, and copolymer constituents were different, and the constituents and the evaluation results are shown in Table 1.

Example 9

Experiment was carried out in the same manner as in Example 1, except that (C): B-80 pigment was substituted with methacrylate in the structural unit of the acrylic resin containing an organic group derived from a carboxyl group and a pigment. And the evaluation results are shown in Table 1.

Example 10

Experiment was carried out in the same manner as in Example 1, except that (C): O-16 pigment-substituted methacrylate was used in the structural unit of the acrylic resin containing an organic group derived from a carboxyl group and a pigment. And the evaluation results are shown in Table 1.

Comparative example

Instead of using acrylic resins containing organic groups derived from carboxyl groups and pigments

 (1) 6 g of copolymer resin (benzyl methacrylate / methacrylic acid)

    (A) / (B) = 75/25 (mol%), molecular weight (Mw) = 22,000

    (A): benzyl methacrylate

    (B): methacrylic acid

 (6) 6 g of a pigment dispersion of R-254

Except for using the same as in Example 1.

Experimental results of Examples 1 to 10 and Comparative Examples will be described with reference to FIGS. 2 to 5.

2 to 5 are photographs that can compare the occurrence of the residue of the pixel, Figure 2 is prepared using the photosensitive resin composition according to the present invention, Figure 3 is prepared using a conventional pigment dispersion. Comparing FIG. 2 with FIG. 3, it can be seen that the residue is badly generated in the non-exposed part of FIG. 3.

4 and 5 are photographs in which the resolution of 1 × 1 μm pixels can be compared, and FIG. 4 is a photosensitive resin composition according to the present invention, and FIG. 5 is a conventional pigment dispersion. In contrast to the rectangular shape, it can be seen that FIG. 5 has a very irregular shape.

Acrylic resins containing organic groups derived from carboxyl groups and pigments Pixel (□) Composition (composition ratio, mol%) Molecular Weight Acid profile Residue Resolution (μm, minimum identifiable pixel) A B C D E Example 1 68 25 7 - - 25000 100 ○ ○ 0.6 × 0.6 Example 2 68 25 7 - - 10000 100 ○ ○ 0.6 × 0.6 Example 3 68 25 7 - - 60000 100 ○ △ 0.6 × 0.6 Example 4 75 18 7 - - 25000 60 ○ △ 0.6 × 0.6 Example 5 63 30 7 - - 25000 130 △ ○ 0.6 × 0.6 Example 6 48 25 7 Styrene (20) - 25000 100 ○ ○ 0.8 × 0.8 Example 7 33 25 7 Styrene (20) 2-Hydroxy ethylacrylate (15) 25000 100 ○ ○ 0.8 × 0.8 Example 8 68 25 7 - - 25000 100 △ ○ 0.6 × 0.6 Example 9 68 25 7 - - 25000 100 △ ○ 1.0 × 1.0 Example 10 68 25 7 - - 25000 100 △ ○ 1.0 × 1.0 Comparative example 75 25 - - - 25000 100 △ × 1.2 × 1.2

The evaluation of the profile among the evaluation items in Table 1 was observed by observing the pattern cross section by SEM with respect to the pixel pattern formed by the 250 ms exposure dose, and indicating that the profile was a good rectangular profile O, △ slightly rounded shape, completely round or irregular. The shape was evaluated by X.

In addition, the item about the residue is evaluated by observing the pattern cross section by SEM with respect to the pixel pattern formed by the 250 ms exposure amount, and evaluating the case where there is no residue at all in the unexposed part, △ when there exists a little, and the case where it is seen clearly. It is.

It can be seen that Example 1 and Example 2 are the best in terms of profile, residue, and resolution, and the comparative example using the conventional pigment dispersion can be seen that all surfaces, in particular, residue and resolution are poor.

As described above, the photosensitive resin composition of the present invention and the color filter using the same are used after the pigment is introduced in advance through a chemical reaction with a binder resin, thereby easily forming an ultra-fine square pattern required for a 10 million pixel image sensor. In addition, since the residue of the non-exposed part does not occur during development, it can be effectively used to manufacture a color filter for a high resolution image sensor.

Claims (11)

The photosensitive resin composition WHEREIN: The resin is an acrylic resin containing the organic group derived from a carboxy group and a pigment, The photosensitive resin composition characterized by the above-mentioned. The photosensitive resin composition of claim 1, wherein the acrylic resin containing a pigment and a carboxyl group has a structure represented by the following Chemical Formula 1.

(A is a repeating unit of an ethylenically unsaturated monomer containing no carboxyl group,  X: O or NH, PIG is an organic group derived from the pigment.) The method of claim 1, wherein the composition (1) 0.5 to 20% by weight of an acrylic resin containing an organic group derived from a carboxyl group and a pigment; (2) 0.5 to 20% by weight of an acrylic photopolymerizable monomer; (3) 0.1 to 10 wt% of a photopolymerization initiator;     And a solvent as a residual amount. The photosensitive resin composition according to claim 1, wherein the acrylic resin containing an organic group derived from the carboxyl group and the pigment has a molecular weight (M.W.) of 10,000 to 70,000. The photosensitive resin composition according to claim 1, wherein the acrylic resin containing the organic group derived from the carboxyl group and the pigment has a repeat unit molar ratio of 10 to 40 mol% of the carboxyl group-containing ethylenically unsaturated monomer. The photosensitive resin composition according to claim 1, wherein the acrylic resin containing the organic group derived from the carboxyl group and the pigment has a molar ratio of 3 to 20 mol% of the repeating unit molar ratio of the monomer including the pigment. The method of claim 1, wherein the pigment (PIG) comprises a hydroxyl group or an amine group, Red 254, Red 177, Yellow 139, Yellow 150, Yellow 185, Yellow 214, Blue 80, Blue 60, Orange 16, and Orange 36 The photosensitive resin composition, characterized in that any one selected from the group consisting of. The photosensitive resin composition of Claim 2 using a triazine type compound as said photoinitiator. The photosensitive resin composition according to claim 8, wherein the triazine-based compound uses a compound having a maximum light absorption wavelength (λ max) in the range of 340 to 380 nm. The photosensitive resin composition of claim 1, wherein the composition further comprises 0.1 to 1% by weight of any one or more of malonic acid, 3-amino-1,2-propanediol, and a fluorine-based surfactant as an additive. The color filter for an image sensor manufactured by forming a pattern through the process of apply | coating, prebaking, exposing, developing, and postbaking the photosensitive resin composition of any one of Claims 1-10.

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