TWI825195B - Resin composition and method for manufacturing substrate with microlens pattern - Google Patents

Abstract

An object of the present invention is to provide a resin composition based on a dot pattern composed of rectangular dots and grid-like intervals and a method for manufacturing a substrate having a microlens pattern using the resin composition. Type heating is used to form a dot pattern when heat flows in a dot pattern to form a microlens pattern, and it is possible to form a dot pattern that can flow heat well even at low temperatures. The solution of the present invention relates to a resin composition for forming a dot pattern when a dot pattern consisting of rectangular dots and grid-like intervals is heated to cause heat flow in the dot pattern to form a microlens pattern. , the glass transition temperature Tg measured under specific conditions of the resin film formed using the resin composition is 70°C or lower.

Description

Resin composition and method for manufacturing substrate with microlens pattern

The present invention provides a resin composition and a method for manufacturing a microlens pattern using the resin composition.

Currently, solid-state imaging elements are installed in widely used digital cameras, camera-equipped mobile phones, and the like. Typical solid-state imaging elements include a CCD (charge coupled device) image sensor or a CMOS (complementary metal-oxide semiconductor) image sensor. In these image sensors, fine lenses (hereinafter referred to as microlenses) are provided for the purpose of improving sensitivity. In the manufacturing of image sensors, in addition to microlenses, other parts such as color filters are also formed if necessary.

In recent years, the miniaturization of solid-state imaging elements and the increase in the number of imaging pixels have been progressed, and various research and development have been carried out in order to improve the light collection efficiency. For example, Patent Document 1 proposes to apply a photoresist film on the planarization layer formed on the upper side of the light receiving portion of the solid-state imaging element, expose the photoresist film through a photomask, and then develop the exposed photoresist film to develop the photoresist film. A method of patterning photoresist films into lens shapes. In the method described in Patent Document 1, the photoresist film is exposed using a mask formed with a light-transmitting portion composed of a medium having a light refraction system with a step portion on the surface. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2003-98649

[Problem to be solved by the invention]

On the other hand, after the precursor pattern of the microlens pattern made of the resin composition is formed, the microlens pattern can also be formed by heat-treating the precursor pattern to cause heat flow. In the method described in Patent Document 1, a photomask with a precisely designed shape must be used. Such masks are expensive and difficult to manufacture. However, if the heat flow method is used, there is no need to use the photomask described in Patent Document 1.

Regarding the above-mentioned manufacturing method of microlens patterns by thermal flow, it is required to achieve good formation even if the heating temperature is lowered from the viewpoint of the heat resistance of the material used for the solid-state imaging element or the reduction of the manufacturing energy of the microlens pattern. Heat-flowing patterned resin composition.

The present invention was accomplished in view of the above problems, and aims to provide a resin composition that combines rectangular dots and grid-shaped dots and a method for manufacturing a substrate having a microlens pattern using the resin composition. When the dot pattern formed by the spacing is heated to cause heat flow in the dot pattern to form a microlens pattern, it is used to form a dot pattern and can form a dot pattern that can flow heat well even at low temperatures. [Means to solve the problem]

The inventors of the present invention discovered that when a dot pattern consisting of rectangular dots and grid-like intervals is heated to cause heat flow in the dot pattern to form a microlens pattern, the resin composition used to form the dot pattern By setting the glass transition temperature Tg measured under specific conditions of a resin film formed using this resin composition to 70° C. or lower, the above problems can be solved, and the present invention has finally been completed. More specifically, the present invention provides the following.

A first aspect of the present invention is a resin composition, which is a microlens pattern formed by heating a dot pattern including rectangular dots and grid-like spaces to cause heat flow in the dot pattern. In the pattern forming method, the resin composition used to form the aforementioned dot pattern, The resin composition contains resin (A), The glass transition temperature Tg of the resin film formed using the resin composition measured according to the method including the following steps (1) to (4) is 70°C or less; (1) The step of spin-coating the resin composition on the substrate to form a coating film, (2) The step of heating the coating film at 100°C for 90 seconds to form a resin film, (3) The steps of collecting a sample for measuring the glass transition point from the obtained resin film, using the obtained sample, performing a differential scanning calorimeter (DSC) measurement to obtain a reversing heat flow curve, and (4) The step of determining the value of the glass transition temperature Tg by reading the minimum value in the differential curve derived by first differentiating the obtained reverse heat flow curve with temperature as the glass transition temperature Tg.

A second aspect of the present invention is a method for manufacturing a substrate with a microlens pattern, which includes: The step of forming a dot pattern including rectangular dots and grid-like intervals on a substrate using the resin composition of the first aspect, and The heat flow step of causing heat flow by heating the dot pattern. [Effects of the invention]

According to the present invention, it is possible to provide a resin composition based on a dot pattern composed of rectangular dots and grid-like intervals and a method for manufacturing a substrate having a microlens pattern using the resin composition. Type heating is used to form a dot pattern when heat flows in a dot pattern to form a microlens pattern, and it is possible to form a dot pattern that can flow heat well even at low temperatures.

[Form of carrying out the invention] ≪Resin composition≫

The resin composition is used to form a dot pattern by heating a dot pattern consisting of rectangular dots and grid-like intervals to cause heat flow in the dot pattern to form a microlens pattern. type. Here, the microlens pattern is a pattern formed by two or more microlenses respectively arranged at designated positions.

The resin composition contains resin (A). Furthermore, the glass transition temperature Tg of the resin film formed using the resin composition measured according to the method including the following steps (1) to (4) is 70°C or less. The Tg value is more preferably 68°C or lower, particularly preferably 66°C or lower. (1) The step of spin-coating the resin composition on the substrate to form a coating film, (2) The step of heating the coating film at 100°C for 90 seconds to form a resin film, (3) The steps of collecting a sample for measuring the glass transition point from the obtained resin film, using the obtained sample, performing a differential scanning calorimeter (DSC) measurement to obtain a reversing heat flow curve, and (4) The step of determining the value of the glass transition temperature Tg by reading the minimum value in the differential curve derived by first differentiating the obtained reverse heat flow curve with temperature as the glass transition temperature Tg. Moreover, the lower limit of Tg is preferably 40°C or higher, more preferably 50°C or higher, and particularly preferably 55°C or higher.

Since the resin composition has the above-mentioned thermal properties, good heat flow at low temperatures can be achieved in the dot pattern formed using the resin composition.

The Tg measured by the above method can be adjusted, for example, by appropriately changing the chemical structure of the structural units constituting the resin (A). In addition, when the resin (A) contains two or more types of plural structural units, the Tg measured by the above method can be adjusted by changing the ratio of the structural units. In addition, when the resin composition contains a photosensitive agent (B) as described later, the Tg measured by the above method can be adjusted by changing the type or content of the photosensitive agent (B) contained in the resin composition.

The method of forming the dot pattern is not particularly limited. For example, the dot pattern can be formed by a printing method such as inkjet printing. Dot patterns can also be formed by patterning lithography that involves exposure and development.

As the resin composition, a photosensitive resin composition capable of forming a dot pattern by a photolithography method is preferred because it is easy to form a fine and well-shaped dot pattern.

Regarding the dot pattern formed using the resin composition, the width of the intervals is preferably 0.2 μm or more and 2.0 μm or less, more preferably 0.25 μm or more and 1.0 μm or less. Furthermore, when the width of the space is W and the height of the dot is H, the aspect ratio represented by H/W is preferably 1.0 or more and 10.0 or less, more preferably 2.0 or more and 8.0 or less. The height H of the dots is not particularly limited, but is typically preferably from 0.25 μm to 4.0 μm, more preferably from 0.5 μm to 2.0 μm. Also, the dot pattern is formed on the substrate. Each dot constituting the dot pattern usually has a rectangular parallelepiped shape, a cubic shape, or a shape similar to these shapes, and the size of the dot in the same direction as the thickness direction of the substrate is regarded as the height H of the dot.

Furthermore, the shape of the rectangular surface whose points are in the same direction as or approximately the same direction as the surface direction of the substrate is a square, a rectangle, or a shape similar to these shapes. Regarding a rectangular surface whose points are in the same direction as or substantially the same direction as the surface direction of the substrate, the length of each of the four sides is preferably 0.5 μm or more and 5 μm or less, more preferably 1 μm or more and 4 μm or less.

Regarding the dot pattern formed using the resin composition, if the width and aspect ratio of the intervals are within the above ranges, it is easy to obtain a microlens pattern of a desired shape after heat flow.

In addition, the temperature of the heat flow of the dot pattern formed using the resin composition is preferably not less than (Tg+5)°C and not more than 130°C, more preferably not less than (Tg+5)°C and not more than 100°C. Due to the temperature within this range, when the dot pattern heat flow formed by the resin composition is used, excessive heat flow of the dot pattern can be suppressed while the dot pattern can be easily heat-flowed to a desired degree.

As a preferable resin composition, a photosensitive resin composition containing an alkali-soluble resin (A1) as a resin (A) and a photosensitive agent (B) is mentioned. Necessary or optional components contained in the preferred photosensitive resin composition will be described below.

<Alkali-soluble resin (A1)> The alkali-soluble resin (A1) is not particularly limited as long as it is a resin having an alkali-soluble group such as a carboxyl group or a phenolic hydroxyl group and is soluble in an alkaline solution. For example, examples of the alkali-soluble resin (A1) include phenol resins, acrylic resins, copolymers of styrene and acrylic acid, polymers or copolymers of hydroxystyrene, polyvinylphenol, and polyα-methylvinyl Phenol etc.

The alkali-soluble resin (A1) is preferably a (meth)acrylic resin containing a structural unit represented by the following formula (a1), (In the formula (a1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a single bond or an alkylene group having 1 to 5 carbon atoms, R ³ represents an alkyl group having 1 to 5 carbon atoms, and a represents an integer from 1 to 5, b represents an integer from 0 to 4, a+b is 5 or less, and b is 2 or more, the plural R ³ may be the same or different from each other).

When the (meth)acrylic resin contains the structural unit represented by the above formula (a1), it is easy to obtain good patterning properties when forming a dot pattern using the photosensitive resin composition.

In the above formula (a1), when R ² is an alkylene group having 1 to 5 carbon atoms, the alkylene group may be linear or branched. Specific examples of the alkylene group of R ² include methylene, ethane-1,2-diyl, ethane-1,1-diyl, propane-1,3-diyl, and propane-1 ,2-diyl, propane-1,1-diyl, propane-2,2-diyl, butane-1,4-diyl, butane-1,3-diyl, butane-1,2 -Diyl, butane-1,1-diyl, butane-2,3-diyl, butane-2,2-diyl, pentane-1,5-diyl, pentane-1,4 -Diyl, pentane-1,3-diyl, pentane-1,2-diyl, pentane-1,1-diyl, pentane-2,4-diyl, pentane-2,3 -diyl, pentane-2,2-diyl and pentane-3,3-diyl.

As R ² described above, it is easy to obtain or synthesize a compound that can provide the structural unit represented by formula (a1), or it is easy to form a dot pattern that can flow at low temperature well using a resin composition. From a certain point of view, single bond, methylene and ethane-1,2-diyl are preferred, single bond and methylene are more preferred, and single bond is particularly preferred.

In the above formula (a1), R ³ is an alkylene group having 1 to 5 carbon atoms. The alkylene group of R ³ may be linear or branched. Specific examples of the alkylene group of R ³ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, second-butyl, third-butyl, n-pentyl, Isopentyl, neopentyl, second pentyl, third pentyl and pentan-3-yl.

In the formula (a1), a, the number of hydroxyl groups on the benzene ring, is an integer from 1 to 5. As a, 1 or 2 is preferable, and 1 is more preferable from the viewpoint of easy acquisition or synthesis of a compound that can provide a structural unit represented by formula (a1).

In the formula (a1), at least one of the one or more hydroxyl groups is bonded to the benzene ring, preferably bonded to the para position with respect to the position to which the group represented by -CO-OR ² - is bonded. .

As the structural unit represented by the formula (a1), for example, a structural unit represented by the following formula (a1-1) or the following formula (a1-2) is preferred. In formula (a1-1) and formula (a1-2), R ¹ is a hydrogen atom or a methyl group.

In the (meth)acrylic resin containing the structural unit represented by formula (a1), the content of the structural unit represented by formula (a1) is preferably 20 mass% or more and 80 mass% or less, more preferably 20 mass% More than 70 mass %, particularly preferably 20 mass % or more and 60 mass % or less, particularly preferably 20 mass % or more and 50 mass % or less. In the (meth)acrylic resin containing the structural unit represented by the formula (a1), the lower limit of the content of the structural unit represented by the formula (a1) is also preferably 25 mass% or more or 30 mass% or more. In the (meth)acrylic resin containing the structural unit represented by the formula (a1), if the content of the structural unit represented by the formula (a1) is within the above range, it is easy to use the photosensitive resin composition to form spots. Good patterning properties between patterns and good low-temperature thermal fluidity of dot patterns.

The (meth)acrylic resin containing the structural unit represented by the above formula (a1) preferably further contains 1 or more carbon atoms derived from (meth)acrylic acid together with the structural unit represented by the above formula (a1). The structural unit of alkyl esters below 10. In this case, a photosensitive resin composition can be used, and it is particularly easy to form a dot pattern with excellent low-temperature thermal fluidity.

The alkyl ester of (meth)acrylic acid having 1 to 10 carbon atoms is preferably an alkyl ester of (meth)acrylic acid having 2 to 6 carbon atoms, more preferably the alkyl ester of (meth)acrylic acid having 2 to 6 carbon atoms. Alkyl esters from 3 to 5. The alkyl group constituting the alkyl ester may be linear or branched, and is preferably linear.

Preferable specific examples of the alkyl ester of (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. Ester, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, (meth)acrylate ) n-heptyl acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate and n-decyl (meth)acrylate. Among these, preferred are ethyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, and n-pentyl (meth)acrylate. ester and n-hexyl (meth)acrylate.

In the (meth)acrylic resin containing the structural unit represented by formula (a1), the content of the structural unit of the alkyl ester having 1 to 10 carbon atoms derived from (meth)acrylic acid is preferably 10 mass % or more. 80 mass% or less, more preferably 15 mass% or more and 80 mass% or less, particularly preferably 20 mass% or more and 80 mass% or less.

The (meth)acrylic resin containing the structural unit represented by formula (a1) may also contain the structural unit represented by formula (a1) and (meth)acrylic acid-derived Other structural units other than the structural units of alkyl esters having 1 to 10 carbon atoms. Examples of the monomer that provides the other structural unit include (meth)acrylates that do not have an epoxy group other than alkyl esters of (meth)acrylic acid having 1 to 10 carbon atoms, and those that have an epoxy group. Unsaturated compounds, (meth)acrylamides, allyl compounds, vinyl ethers, vinyl esters, styrenes, etc. These compounds can be used individually or in combination of 2 or more types.

Examples of (meth)acrylates that do not have an epoxy group include chloroethyl (meth)acrylate, 2,2-dimethylhydroxypropyl (meth)acrylate, and 2-(meth)acrylate. Hydroxyethyl ester, trimethylolpropane mono(meth)acrylate, (meth)acrylic benzoate and (meth)acrylic acid furfuryl ester, etc.

Examples of the unsaturated compound having an epoxy group include epoxypropyl (meth)acrylate, 2-methylepoxypropyl (meth)acrylate, and 3,4-epoxybutyl (meth)acrylate. Ester, 6,7-epoxyheptyl (meth)acrylate, and other epoxyalkyl (meth)acrylates: α-ethyl glycidyl acrylate, α-n-propyl glycidyl acrylate , α-n-butyl glycidyl acrylate, α-ethyl acrylate 6,7-epoxyheptyl, α-alkyl acrylic acid epoxy alkyl esters, etc. As the unsaturated compound having an epoxy group, a (meth)acrylate having an alicyclic group containing an epoxy group is also preferred.

Examples of (meth)acrylamides include (meth)acrylamide, N-alkylacrylamide, N-aryl(meth)acrylamide, and N,N-dialkyl(meth)acrylamide. acrylamide, N,N-aryl(meth)acrylamide, N-methyl-N-phenyl(meth)acrylamide, N-hydroxyethyl-N-methyl(methyl ) acrylamide, etc.

Examples of the allyl compound include allyl acetate, allyl caproate, allyl octanoate, allyl laurate, allyl palmate, allyl stearate, and allyl benzoate. , allyl esters such as allyl acetyl acetate, allyl lactate, etc.; allyloxyethanol, etc.

Examples of vinyl ethers include hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, and ethoxyethyl vinyl ether. , Chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethylbutyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether , alkyl groups such as dimethylaminoethylvinyl ether, diethylaminoethylvinylether, butylaminoethylvinylether, benzylvinylether, tetrahydrofurfurylvinylether, etc. Vinyl ether; vinyl phenyl ether, vinyl tolyl ether, vinyl chlorophenyl ether, vinyl-2,4-dichlorophenyl ether, vinyl naphthyl ether, vinyl anthracenyl ether, etc. Aryl ethers, etc.

Examples of the vinyl esters include vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl hexanoate, vinyl chloroacetate, and dimethyl acetate. Vinyl chloroacetate, vinyl methoxy acetate, vinyl butoxy acetate, vinyl phenyl acetate, vinyl acetate, vinyl lactate, vinyl-β-phenyl butyrate, vinyl benzoate, Vinyl salicylate, vinyl chlorobenzoate, vinyl tetrachlorobenzoate, vinyl naphthoate, etc.

Examples of styrenes include styrene; methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, butylstyrene, Hexylstyrene, cyclohexylstyrene, decylstyrene, benzylstyrene, chloromethylstyrene, trifluoromethylstyrene, ethoxymethylstyrene, acetyloxymethylstyrene, etc. Alkyl styrene; methoxystyrene, 4-methoxy-3-methylstyrene, dimethoxystyrene and other alkoxystyrenes; chlorostyrene, dichlorostyrene, trichlorobenzene Ethylene, tetrachlorostyrene, pentachlorostyrene, bromostyrene, dibromostyrene, iodostyrene, fluorostyrene, trifluorostyrene, 2-bromo-4-trifluoromethylstyrene, 4-fluoro -3-Trifluoromethylstyrene and other halogenated styrenes.

In the (meth)acrylic resin containing the structural unit represented by formula (a1), the amount of other structural units, based on the mass of the (meth)acrylic resin, is not limited to a range that does not hinder the purpose of the present invention. It may be limited to the remaining amount after deducting the mass of the structural unit represented by formula (a1) and the mass of the structural unit derived from the alkyl ester having 1 to 10 carbon atoms derived from (meth)acrylic acid.

The content of the (meth)acrylic resin containing the structural unit represented by the above formula (a1) in the alkali-soluble resin (A1) is preferably 70 mass% or more, more preferably 80 mass% or more, and particularly preferably 90 mass% % or above, the best is 100 mass%.

The molecular weight of the alkali-soluble resin (A1) is not particularly limited, but is preferably 1,000 or more and 20,000 or less, more preferably 1,000 or more and 20,000 or less, expressed as a mass average molecular weight (Mw: a value measured in terms of styrene by gel permeation chromatography (GPC)). The best value is more than 1,500 and less than 15,000, and the best value is more than 2,000 but less than 10,000.

＜Photosensitizer (B)＞ The photosensitive agent (B) improves the solubility of the photosensitive resin composition in an alkali developing solution by exposure. The photosensitizer (B) is preferably a quinonediazide group-containing compound.

Examples of the quinonediazide group-containing compound include a complete esterified product or a partially esterified product of a phenol compound and a naphthoquinonediazide sulfonic acid compound. Examples of the phenol compound include polyhydroxydiphenylketone compounds such as 2,3,4-trihydroxydiphenylketone and 2,3,4,4'-tetrahydroxydiphenylketone; tris(4 -Hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,3,5-trimethylphenyl)-2-hydroxy Phenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-4-hydroxyphenylmethane, bis(4-hydroxy-3,5-dimethylphenyl)-3-hydroxyphenyl Methane, bis(4-hydroxy-3,5-dimethylphenyl)-2-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-4-hydroxyphenylmethane, Bis(4-hydroxy-2,5-dimethylphenyl)-3-hydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-2-hydroxyphenylmethane, bis( 4-hydroxy-3,5-dimethylphenyl)-3,4-dihydroxyphenylmethane, bis(4-hydroxy-2,5-dimethylphenyl)-3,4-dihydroxyphenyl Methane, bis(4-hydroxy-2,5-dimethylphenyl)-2,4-dihydroxyphenylmethane, bis(4-hydroxyphenyl)-3-methoxy-4-hydroxyphenylmethane , bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-4-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3-hydroxybenzene methylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-2-hydroxyphenylmethane, bis(5-cyclohexyl-4-hydroxy-2-methylphenyl)-3, Triphenol-type compounds such as 4-dihydroxyphenylmethane; 2,4-bis(3,5-dimethyl-4-hydroxybenzyl)-5-hydroxyphenol, 2,6-bis(2,5- Linear 3-core phenol compounds such as dimethyl-4-hydroxybenzyl)-4-methylphenol; 1,1-bis[3-(2-hydroxy-5-methylbenzyl)-4-hydroxy- 5-cyclohexylphenyl]isopropane, bis[2,5-dimethyl-3-(4-hydroxy-5-methylbenzyl)-4-hydroxyphenyl]methane, bis[2,5-di Methyl-3-(4-hydroxybenzyl)-4-hydroxyphenyl]methane, bis[3-(3,5-dimethyl-4-hydroxybenzyl)-4-hydroxy-5-methylbenzene methyl]methane, bis[3-(3,5-dimethyl-4-hydroxybenzyl)-4-hydroxy-5-ethylphenyl]methane, bis[3-(3,5-diethyl- 4-hydroxybenzyl)-4-hydroxy-5-methylphenyl]methane, bis[3-(3,5-diethyl-4-hydroxybenzyl)-4-hydroxy-5-ethylphenyl ]methane, bis[2-hydroxy-3-(3,5-dimethyl-4-hydroxybenzyl)-5-methylphenyl]methane, bis[2-hydroxy-3-(2-hydroxy-5 -Methylbenzyl)-5-methylphenyl]methane, bis[4-hydroxy-3-(2-hydroxy-5-methylbenzyl)-5-methylphenyl]methane, bis[2, 5-Dimethyl-3-(2-hydroxy-5-methylbenzyl)-4-hydroxyphenyl]methane and other linear 4-core phenolic compounds; 2,4-bis[2-hydroxy-3-( 4-hydroxybenzyl)-5-methylbenzyl]-6-cyclohexylphenol, 2,4-bis[4-hydroxy-3-(4-hydroxybenzyl)-5-methylbenzyl]-6 - Linear type 5 of cyclohexylphenol, 2,6-bis[2,5-dimethyl-3-(2-hydroxy-5-methylbenzyl)-4-hydroxybenzyl]-4-methylphenol, etc. Linear polyphenol compounds such as core phenol compounds; bis(2,3,4-trihydroxyphenyl)methane, bis(2,4-dihydroxyphenyl)methane, 2,3,4-trihydroxyphenyl- 4'-Hydroxyphenylmethane, 2-(2,3,4-trihydroxyphenyl)-2-(2',3',4'-trihydroxyphenyl)propane, 2-(2,4-di Hydroxyphenyl)-2-(2',4'-dihydroxyphenyl)propane, 2-(4-hydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(3-fluoro- 4-hydroxyphenyl)-2-(3'-fluoro-4'-hydroxyphenyl)propane, 2-(2,4-dihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2 -(2,3,4-trihydroxyphenyl)-2-(4'-hydroxyphenyl)propane, 2-(2,3,4-trihydroxyphenyl)-2-(4'-hydroxy-3 Bisphenol compounds such as ',5'-dimethylphenyl)propane; 1-[1-(4-hydroxyphenyl)isopropyl]-4-[1,1-bis(4-hydroxyphenyl) )ethyl]benzene, 1-[1-(3-methyl-4-hydroxyphenyl)isopropyl]-4-[1,1-bis(3-methyl-4-hydroxyphenyl)ethyl Multinuclear branched compounds such as benzene; condensed phenol compounds such as 1,1-bis(4-hydroxyphenyl)cyclohexane, etc. These can be used 1 type or in combination of 2 or more types.

Examples of the naphthoquinonediazide sulfonic acid compound include naphthoquinone-1,2-diazide-5-sulfonyl chloride or naphthoquinone-1,2-diazide-4-sulfonyl chloride. Chlorine etc.

In addition, other compounds containing quinonediazide groups can also be used, such as o-benzoquinonediazide, o-naphthoquinonediazide, o-anthraquinonediazide or o-naphthoquinonediazide sulfonate esters, etc. These nuclear substituted derivatives, and o-quinonediazide sulfonyl chloride and compounds with hydroxyl or amine groups such as phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol , Catechol, gallic acid, gallic acid monomethyl ether, gallic acid-1,3-dimethyl ether, gallic acid, esterified or etherified gallic acid, phenol, Reaction products of p-aminodiphenylamine, etc. These systems can be used individually or in combination of two or more types.

These quinonediazide-containing compounds can be prepared, for example, by mixing the above-mentioned phenol compound with naphthoquinone-1,2-diazide-5-sulfonate chloride or naphthoquinone-1,2-diazide. It is manufactured by condensing 4-sulfonyl chloride in an appropriate solvent such as dimethane in the presence of a base such as triethanolamine, alkali metal carbonate, alkali metal bicarbonate, etc., and causing complete or partial esterification. .

Relative to the mass of the resin (A), the usage amount of the photosensitive agent (B) is preferably 50 mass% or less, more preferably 40 mass% or less, and particularly preferably 30 mass% or less. The lower limit of the usage amount of the photosensitive agent (B) is, for example, 10% by mass or more, preferably 15% by mass or more, and more preferably 20% by mass or less based on the mass of the resin (A). By using the photosensitive agent (B) in an amount within such a range, the above-mentioned resin composition having an appropriate Tg value can be easily prepared. As a result, it is easy to achieve both good patterning characteristics when forming a dot pattern using the photosensitive resin composition and good low-temperature thermal fluidity of the dot pattern.

(other ingredients) The photosensitive resin composition containing the alkali-soluble resin (A1) and the photosensitive agent (B) as the resin (A) may contain other components other than the alkali-soluble resin (A1) and the photosensitive agent (B) if necessary. Examples of other components include organic solvents and thermal crosslinking agents. When the photosensitive resin composition contains a thermal crosslinking agent, the heat resistance of the formed microlens can be improved, and excessive heat flow of the dot pattern can be easily suppressed.

The thermal cross-linking agent is not particularly limited, and for example, the same ones as well-known cross-linking agents can be appropriately selected and used. For example, melamine resin, urea resin, guanamine resin, acetylene urea-formaldehyde resin, succinamide-formaldehyde resin, ethylene urea-formaldehyde resin, etc. can be used. In particular, alkoxymethylated amine resins such as alkoxymethylated melamine resin and alkoxymethylated urea resin can be suitably used. Among them, suitable specific examples of the thermal crosslinking agent include methoxymethylated melamine resin, propoxymethylated melamine resin, butoxymethylated melamine resin, and methoxymethylated urea. Resin, ethoxymethylated urea resin, propoxymethylated urea resin and butoxymethylated urea resin, etc.

The resin composition is prepared by uniformly mixing the above-described components.

≪Method for manufacturing substrate with microlens pattern≫ Using the resin composition described above, a substrate having a microlens pattern is produced. Specifically, the manufacturing method of a substrate with a microlens pattern includes: The step of using the aforementioned resin composition to form a dot pattern including rectangular dots and grid-like intervals on a substrate, and The heat flow step of causing heat flow by heating the dot pattern.

In addition, when the shape and size of the dot pattern is defined as the width of the space in the dot pattern as W and the height of the dot as H, the preferred range of the aspect ratio H/W is determined by the resin composition. Things mentioned above.

The substrate is not particularly limited as long as it has been conventionally used as a substrate for forming microlens patterns. An example of a suitable substrate is a substrate in which a solid-state imaging element, a first planarizing film, a color filter, and a second planarizing film are formed on a silicon substrate. On this substrate, a first planarizing film having a flat surface is formed to cover the solid-state imaging elements scattered at designated positions on the silicon substrate. A color filter is formed on the first planarizing film at a position above the position of each solid-state imaging element. Then, a second planarizing film having a flat surface is formed to cover the color filter. In addition, in the substrate, the direction from the silicon substrate toward the second planarizing film side is regarded as upward, and the direction from the second planarizing film toward the silicon substrate side is regarded as downward.

Hereinafter, a method of forming a microlens pattern on a substrate will be described with reference to FIG. 1 .

＜Steps to form dot pattern＞ As shown in FIG. 1(b), in order to form a microlens pattern on the substrate 10, first, the dot pattern 12 is formed on the substrate 10 using the above-mentioned resin composition. The method of forming the dot pattern 12 is not particularly limited. For example, as mentioned above, the dot pattern 12 can be formed by a printing method such as inkjet printing. The dot pattern 12 can also be formed by a patterning photolithography method including exposure and development.

The detailed recipe of the lithography method is appropriately selected according to the types of components contained in the resin composition or the composition of the resin composition.

For example, when using a positive photosensitive resin composition including an alkali-soluble resin (A1) and a photosensitive agent (B), which is a preferred resin composition, first, as shown in FIG. 1(a) , the substrate 10 is coated with The resin composition forms the coating film 11. The coating method is not particularly limited, and for example, a known method using a roll coater or a spin coater can be used.

When the coating film 11 contains a volatile component such as a solvent, the volatile component can be removed from the coating film 11 if necessary. As a method of removing volatile components, a method of placing the coating film 11 in a reduced pressure environment or a method of heating the coating film 11 is preferred. However, the coating film 11 is also easy to thermally fluidize at low temperatures, so the dot pattern system has excellent low-temperature thermal fluidity. Therefore, when removing volatile components from the coating film 11, if necessary, place it in a reduced pressure environment. It is preferable to heat the coating film 11 for a short time at a temperature (Tg + 50° C. or lower). 120 seconds or less, preferably 90 seconds or less.

Next, after the coating film 11 is exposed through a mask of a specified shape, the exposed coating film 11 is developed to form a dot pattern 12 as shown in FIG. 1(b) .

Exposure is performed by irradiating active energy rays such as ultraviolet rays and excimer laser light, for example. The amount of energy rays to be irradiated varies depending on the composition of the photosensitive resin composition, but for example, it is preferably about 30 mJ/cm ² or more and 2000 mJ/cm ² or less.

As the developing solution, for example, an organic alkali aqueous solution such as tetramethylammonium hydroxide (TMAH) aqueous solution or an inorganic alkali aqueous solution such as sodium hydroxide, potassium hydroxide, sodium metasilicate, and sodium phosphate can be used.

For the dot pattern 12 formed as above, bleaching by full exposure can be performed. By this bleaching, the transparency of the dot pattern 12 increases. By performing bleaching, a photoreaction of the photosensitive agent (B) contained in the resin composition, such as a quinonediazide group-containing compound, occurs, and the transparency of the dot pattern 12 increases. As a bleaching method, specifically, it is preferable to irradiate ultraviolet rays with a wavelength in the range of 300 nm to 450 nm. Even if bleaching is not performed, if the transparency of the dot pattern 12 is good, bleaching may be omitted if necessary.

＜Hot flow step＞ By heating the optionally bleached dot pattern 12, the dot pattern 12 can be thermally flowed. By this heat flow, the microlens pattern 13 is formed on the substrate 10 .

The temperature of heat flow is preferably (Tg+5)°C or more and not more than 130°C, more preferably (Tg+5)°C or more and not more than 100°C. When the dot pattern 12 formed of the resin composition is heat-flowed at a temperature within this range, excessive heat flow of the dot pattern 12 can be suppressed while making it easy to heat-flow the dot pattern 12 to a desired degree. .

Through the method described above, the dot pattern can be made to have good heat flow even at low temperatures, thereby forming a good microlens pattern. [Example]

Hereinafter, an Example is given and this invention is demonstrated in more detail. The present invention is not limited by these examples.

[Examples 1 to 4, Comparative Example 1 and Comparative Example 2] In Examples 1 to 4, the following explains how to uniformly mix the resin (A), the photosensitive agent (B), and the solvent to prepare a photosensitive resin composition.

<Resin (A)> In each of the Examples and Comparative Examples, 100 parts by mass of a copolymer containing units represented by the following formulas A-1, A-2, and A-3 at the mass ratio shown in Table 1 below was used. Resin(A). The mass average molecular weight (Mw) of the copolymer used in each example and comparative example is 8,000.

<Photosensitive agent (B)> In each of the Examples and Comparative Examples, as the photosensitive agent (B), the hydrogen atom in the hydroxyl group of the compound represented by the following formula in the amount described in Table 1 was converted to 1,2- Substituent substituted by naphthoquinone diazide-5 sulfonyl group. The substitution rate of hydrogen atoms in the hydroxyl groups of the photosensitive agent with 1,2-naphthoquinonediazide-5-sulfonyl groups is 98.7 mol%.

Each Example was obtained by dissolving 100 parts by mass of the resin (A) and the amount of the photosensitizer (B) described in the following Table 1 in propylene glycol monomethyl ether acetate so that the solid content concentration became 24% by mass. and the resin compositions of each comparative example. For the obtained resin composition, Tg was measured using a differential scanning calorimeter according to the aforementioned method. Table 1 describes the measurement results of Tg. The low-temperature thermal fluidity of the obtained resin composition was evaluated according to the following method. Table 1 describes the evaluation results.

＜Evaluation of low-temperature thermal fluidity＞ The resin compositions of each example and each comparative example were coated on the silicon substrate by a spin coater, and then baked at 90° C. for 90 seconds to form a coating film with a film thickness of 1.8 μm. After position-selective exposure was applied to the formed coating film, a tetramethylammonium hydroxide (TMAH) aqueous solution with a concentration of 2.38 mass % was developed for 60 seconds to form a dot pattern. The shape of the surface of the dots constituting the formed dot pattern that is parallel to the surface direction of the substrate is a square of 4 μm × 4 μm. In addition, the width of the space between dots is 0.5 μm. After the formed dot pattern is heat-flowed under the conditions described in Table 1, the surface of the substrate is observed by electron microscopy to obtain an electron microscopy image. From the obtained electron microscope image, the low-temperature thermal fluidity was evaluated based on the following criteria.

◎The four sides of the dots constituting the dot pattern are deformed into arc shapes that highlight the spacing direction, and the spacing between the dots can be clearly recognized visually.

○Although the heat flow in the dot pattern can be seen, it is difficult to visually identify the intervals between the dots.

×The four sides of the dots constituting the dot pattern are all straight lines, and no heat flow can be seen.

As can be seen from Table 1, when a resin composition is used that has a Tg of 70°C or less for a resin film formed using a resin composition measured by a specified method, even at a low temperature of about (Tg+30)°C, The dot pattern formed by the resin composition has good thermal flow.

On the other hand, it can be seen from the comparative examples that when a resin composition having a Tg value exceeding 70°C is used, the dot pattern formed using the resin composition is almost not heated at a low temperature of about (Tg+30)°C. flow.

10:Substrate

11:Coating film

12: Point pattern

13:Microlens pattern

[Fig. 1] is a diagram schematically showing a method of manufacturing a substrate having a microlens pattern.

10:Substrate

11:Coating film

12: Point pattern

13:Microlens pattern

Claims (10)

A resin composition used in a method for forming a microlens pattern by heating a dot pattern consisting of rectangular dots and grid-like spaces to cause heat flow in the dot pattern. The resin composition forming the dot pattern, the resin composition includes an alkali-soluble resin (A1) as the resin (A) and a photosensitive agent (B), the alkali-soluble resin (A1) contains the following formula (a1) The structural unit shown, and the (meth)acrylic resin of the structural unit derived from the alkyl ester of (meth)acrylic acid having 2 to 6 carbon atoms,

(In the formula (a1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a single bond or an alkylene group having 1 to 5 carbon atoms, R ³ represents an alkyl group having 1 to 5 carbon atoms, and a represents An integer from 1 to 5, b represents an integer from 0 to 4, a+b is 5 or less, and b is 2 or more, the plural R ³ may be the same or different from each other), the above comes from (meth)acrylic acid The ratio of the mass of the structural unit of the alkyl ester having 2 to 6 carbon atoms to the mass of the (meth)acrylic resin is 30 mass % or more and 80 mass % or less, and the resin film is formed using the above resin composition. The glass transition temperature Tg measured according to the method including the following steps (1) to (4) is 70°C or less; (1) the step of spin-coating the above-mentioned resin composition on the substrate to form a coating film , (2) heating the aforementioned coating film at 100°C for 90 seconds to form a resin film, (3) collecting a sample for glass transition point measurement from the obtained aforementioned resin film, and performing differential scanning calorimetry using the obtained aforementioned sample. Measurement of the reverse heat flow curve (DSC), the steps to obtain the reversing heat flow curve, and (4) taking the minimum value in the differential curve derived from the first differentiation of the aforementioned reversing heat flow curve with temperature as the glass The transition temperature Tg is read to determine the value of the aforementioned glass transition temperature Tg. The resin composition of claim 1, wherein the content of the photosensitive agent (B) in the resin composition is 50 mass% or less relative to the mass of the resin (A). The resin composition of claim 1, wherein the mass ratio of the structural unit represented by the formula (a1) to the mass of the (meth)acrylic resin is 20 mass% or more and 80 mass% or less. Such as the resin composition according to any one of claims 1 to 3, which When the width of the space is 0.2 μm or more and 2.0 μm or less, and the width of the space is W, and the height of the dot is H, the aspect ratio represented by H/W is 1.0 or more and 10.0 or less. The resin composition according to any one of claims 1 to 3, wherein the temperature of the thermal flow is (the aforementioned Tg+5)°C or more and not more than 130°C. The resin composition of claim 5, wherein the temperature of the thermal flow is (the aforementioned Tg+5)°C or more and not more than 100°C. A method of manufacturing a substrate with a microlens pattern, which includes: using the resin composition according to any one of claims 1 to 6, forming a dot pattern including rectangular dots and grid-like intervals on the substrate and a heat flow step of causing heat flow by heating the dot pattern. For example, in claim 7, the method for manufacturing a substrate with a microlens pattern, wherein the width of the space is 0.2 μm or more and 2.0 μm or less, assuming the width of the space is W and the height of the dot being H, H/ The aspect ratio represented by W is 1.0 or more and 10.0 or less, and the resin composition according to claim 4 is used to form the dot pattern. As claimed in claim 7, the method for manufacturing a substrate with a microlens pattern, wherein the temperature of the heat flow is above the above-mentioned (Tg+5)°C and below 130°C, The resin composition according to claim 5 is used to form the aforementioned dot pattern. The method for manufacturing a substrate with a microlens pattern according to claim 7, wherein the temperature of the heat flow is above (Tg+5)°C and below 100°C, and the resin composition according to claim 6 is used to perform the dot patterning. form.

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