JP2008115219A - Curable composition for solid state-imaging element and solid state-imaging element by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable composition for a solid state-imaging element, excellent in applicability and curability and obtaining a cured film having a high refractive index and excellent in light transmission, and also a cured film for the solid state-imaging element having a high refractive index by using the same. <P>SOLUTION: This curable composition for the solid state-imaging element contains (A) particles consisting of ≥1 oxide of metal element selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc as a main component and surface-treated by an alkoxysilane compound having a group reacting with the following component (B), (B) a compound expressed by formula (b-1) or (b-2), (C) a compound producing an acid by heating and (D) an organic solvent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a curable composition for a solid-state imaging device and a cured film for a solid-state imaging device using the same.

Patent Document 1 describes that a planarizing film is formed of a polyimide resin having a refractive index larger than that of a microlens. However, since the refractive index of the polyimide resin is not sufficiently large in this solid-state image sensor, the light collection efficiency of the solid-state image sensor on the light receiving portion is not sufficient, and the curing temperature is high, so there is a problem in terms of work accuracy. there were.
Therefore, a layer under the microlens and having a higher refractive index has been demanded.

  On the other hand, a high refractive index material having a refractive index of about 1.7 and improved storage stability using zirconium oxide as metal oxide particles has been disclosed (for example, see Patent Document 2).

It has been suggested that titanium oxide particles, which are metal oxide particles having a high refractive index, are used for the high refractive index material in order to further increase the refractive index.
However, since titanium oxide particles generally have a photocatalytic activity, a film containing such metal oxide particles has a drawback in that its light resistance decreases. The applicant of the present application has invented a technology for coating titanium oxide particles with an oxide of a specific metal element, suppressing the photocatalytic activity of titanium oxide, and improving light resistance (Patent Document 3).
As described above, a high refractive index film having antireflection properties is known, but has a problem that the refractive index is not sufficiently high or light resistance is not sufficient. In addition, a simpler material for a high refractive index film that can be used in a solid-state imaging device has been desired.

Japanese Patent Laid-Open No. 5-134111 JP 2000-186216 A JP 2005-228888 A

  The present invention relates to a curable composition for a solid-state imaging device that is excellent in coating property and curability, has a high refractive index, and is excellent in light transmittance, and a solid-state imaging device having a high refractive index using the same. An object is to provide a cured film.

  As a result of intensive studies, the present inventors have found that a curable composition containing high-refractive-index metal oxide particles, a melamine compound, a curing catalyst, and an organic solvent that are surface-treated with an alkoxysilane compound having a group capable of reacting with a melamine compound Was used as a curable composition for a solid-state imaging device, and the present invention was completed.

（式（ｂ−１）及び（ｂ−２）中、Ｒ^１、Ｒ^３、Ｒ^５は炭素数１〜４のアルキレン基又はアルキリデン基を示し、Ｒ^２、Ｒ^４、Ｒ^６は水素又は炭素数１〜４のアルキル基を示す。）
（Ｃ）加熱により酸を発生する化合物
（Ｄ）有機溶剤
を含有する固体撮像素子用硬化性組成物。
２．前記成分（Ｂ）と反応可能な基を有するアルコキシシラン化合物が、チオール基、水酸基、エポキシ基、アミノ基及びイソシアネート基からなる群から選択される１以上の基を有するトリアルコキシシラン化合物である上記１に記載の固体撮像素子用硬化性組成物。
３．前記成分（Ｂ）がアルコキシメチル化メラミン化合物である上記１又は２に記載の固体撮像素子用硬化性組成物。
４．前記成分（Ｃ）が脂肪族スルホン酸塩、脂肪族カルボン酸塩、芳香族スルホン酸塩、芳香族カルボン酸塩、金属塩及びリン酸エステルからなる群から選択される一種以上の化合物である上記１〜３のいずれかに記載の固体撮像素子用硬化性組成物。
５．前記（Ｄ）有機溶剤が、プロピレングリコールモノメチルエーテル及びシクロヘキサノンからなる群から選択される一以上の溶剤を含むものである上記１〜４のいずれかに記載の固体撮像素子用硬化性組成物。
６．上記１〜５のいずれかに記載の固体撮像素子用硬化性組成物を硬化させてなる屈折率が１．６０以上の固体撮像素子用硬化膜。
７．上記１〜６のいずれかに記載の固体撮像素子用硬化性組成物をスピンコート法により塗布して該組成物の塗布膜を形成した後に、加熱又は放射線を照射して該塗布膜を硬化せしめる工程を有する上記６に記載の固体撮像素子用硬化膜の製造方法。
８．受光部、上記７に記載の硬化膜、マイクロレンズを、この順に含む固体撮像素子。 According to the present invention, the following curable composition for a solid-state imaging device, a cured film comprising the same, a method for producing the cured film, and a solid-state imaging device are provided.
1. The following components (A) to (D):
(A) by an alkoxysilane compound having as a main component an oxide of one or more metal elements selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc, and having a group capable of reacting with the following component (B) Surface-treated particles (B) A compound having a structure represented by the following general formula (b-1) or (b-2)

(In formulas (b-1) and (b-2), R ¹ , R ³ and R ⁵ represent an alkylene group or alkylidene group having 1 to 4 carbon atoms, and R ² , R ⁴ and R ⁶ represent hydrogen or carbon. Represents an alkyl group of formulas 1 to 4.)
(C) The curable composition for solid-state image sensors containing the compound (D) organic solvent which generate | occur | produces an acid by heating.
2. The alkoxysilane compound having a group capable of reacting with the component (B) is a trialkoxysilane compound having one or more groups selected from the group consisting of a thiol group, a hydroxyl group, an epoxy group, an amino group, and an isocyanate group 1. The curable composition for a solid-state imaging device according to 1.
3. 3. The curable composition for a solid-state imaging device according to 1 or 2 above, wherein the component (B) is an alkoxymethylated melamine compound.
4). The component (C) is one or more compounds selected from the group consisting of aliphatic sulfonates, aliphatic carboxylates, aromatic sulfonates, aromatic carboxylates, metal salts, and phosphate esters. The curable composition for solid-state image sensors according to any one of 1 to 3.
5. 5. The curable composition for a solid-state imaging device as described in any one of 1 to 4 above, wherein the (D) organic solvent contains one or more solvents selected from the group consisting of propylene glycol monomethyl ether and cyclohexanone.
6). A cured film for a solid-state imaging device having a refractive index of 1.60 or more obtained by curing the curable composition for a solid-state imaging device according to any one of 1 to 5 above.
7). After applying the curable composition for a solid-state imaging device according to any one of the above 1 to 6 by a spin coat method to form a coating film of the composition, the coating film is cured by heating or irradiation. The manufacturing method of the cured film for solid-state image sensors of said 6 which has a process.
8). A solid-state imaging device including the light receiving unit, the cured film described in 7 above, and a microlens in this order.

According to the curable composition of the present invention, a cured film having excellent coatability and curability, a high refractive index, and excellent light transmittance can be obtained.
According to the present invention, a solid-state imaging device with high light collection efficiency and high sensitivity can be obtained.

  Embodiment (first embodiment) relating to curable composition for solid-state imaging device of the present invention (hereinafter referred to as curable composition of the present invention) and cured film for solid-state imaging device (hereinafter referred to as the cured film of the present invention) ) (Second embodiment) will be specifically described.

[First Embodiment]
The curable composition of the present invention comprises (A) an oxide of one or more metal elements selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc as a main component, and reacts with the following component (B). Particles surface-treated with an alkoxysilane compound having a possible group, and (B) a compound having the structure represented by the general formula (b-1) or (b-2) (hereinafter referred to as a component (B) compound) And (C) a compound that generates an acid by heating, and (D) an organic solvent.

(A) an alkoxysilane compound having as a main component an oxide of one or more metal elements selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc, and having a group capable of reacting with the compound of component (B) Particles surface-treated with (hereinafter referred to as reactive particles (A))
The reactive particle (A) used in the present invention has a function of increasing the refractive index of a cured film obtained by curing the curable composition of the present invention, and further a group capable of reacting with the compound of the component (B). By being surface-treated with the alkoxysilane compound having the above, compatibility with other components is improved, and coating properties, curability and the like can be improved while maintaining a high refractive index.

(1) Particles mainly composed of an oxide of one or more metal elements selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc (hereinafter referred to as metal oxide particles)
The metal oxide particles constituting the reactive particles (A) are particles made of an oxide of one or more metal elements selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc.
The refractive index of the metal oxide particles is usually in the range of 2.7 to 1.8, preferably in the range of 2.7 to 1.9, and preferably in the range of 2.7 to 2.0. Is more preferable. From the viewpoint of high refractive index and stability, the metal oxide particles are preferably oxide particles of zirconium.
When the metal oxide particles are titanium oxide, particles coated with an oxide of one or more metal elements selected from the group consisting of silicon, aluminum, titanium, zirconium, tin, antimony and zinc are used. You can also.
The number average particle diameter of the metal oxide particles (primary particle diameter in the case of aggregation) is preferably 0.1 μm or less. When the number average particle diameter exceeds 0.1 μm, it may be difficult to uniformly disperse the reactive particles (A). In addition, the reactive particles (A) are likely to settle and lack storage stability. Furthermore, the transparency of the obtained cured film may decrease, or turbidity (Haze value) may increase. The number average particle diameter is more preferably 0.005 to 0.08 μm, and further preferably 0.01 to 0.05 μm.

(2) An alkoxysilane compound having a group capable of reacting with the component (B) compound (hereinafter referred to as a reactive silane compound)
The reactive silane compound used in the present invention is a compound having an alkoxysilyl group and a group capable of reacting with the compound of component (B), and forms a bond with the metal oxide particle by the alkoxysilyl group. It can combine with the composition of the component (B) mentioned later.

(I) Group capable of reacting with compound of component (B) Examples of the group capable of reacting with compound of component (B) include hydroxyl group, mercapto group, epoxy group, amino group and isocyanate group. Of these, a hydroxyl group, a mercapto group, and an epoxy group are preferable. The group capable of reacting with the component (B) compound is preferably selected as appropriate in combination with the component (B) compound which is a curable compound.

(Ii) Alkoxysilyl group As the alkoxysilyl group, an alkoxy group having 1 to 3 carbon atoms may be mentioned, and an alkoxy group having 3 to 1 carbon atoms is preferable.

(Iii) Specific examples of reactive silane compounds Examples of reactive silane compounds include, for example, 3-mercaptopropyltrimethoxysilane (Z6062, manufactured by Toray Dow Corning Silicone), 3-mercaptopropyltriethoxysilane (Z6911). Toray Dow Corning Silicone), 3-glycidoxypropyltrimethoxysilane (Z6040, manufactured by Toray Dow Corning Silicone), 3-glycidoxypropyltriethoxysilane (Z6041, Toray Dow Corning Silicone), 3-glycidoxypropylmethyldimethoxysilane (Z6044, manufactured by Toray Dow Corning Silicone), 3-glycidoxypropylmethyldiethoxysilane (Z6042, manufactured by Toray Dow Corning Silicone), 2- (3,4-epoxy Chlorohexyl) ethyltrimethoxysilane (Z6043, manufactured by Toray Dow Corning Silicone), 3-aminopropyltrimethoxysilane (Z6011, manufactured by Toray Dow Corning Silicone), 3-isocyanatopropyltriethoxysilane, and the like. .

(3) Surface treatment of metal oxide particles with reactive silane compound The method of treating the metal oxide particle surface with a reactive silane compound is not particularly limited, but the reactive silane compound and particles are mixed, heated and stirred. It can be manufactured by processing. Note that the reaction is preferably performed in the presence of water in order to efficiently bond the alkoxysilyl group of the reactive silane compound and the particles.
The reaction amount of the reactive silane compound with respect to the particles is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, with the total of the particles and the reactive silane compound being 100% by weight. When it is less than 0.001% by weight. The dispersibility of the particles in the composition is not sufficient, and the applicability and curability of the resulting cured product may not be sufficient.

Hereinafter, the surface treatment method of the metal oxide particles with the reactive silane compound will be described in more detail.
The amount of water consumed by hydrolysis of the alkoxysilyl group during the surface treatment may be an amount by which at least one alkoxy group on silicon in one molecule is hydrolyzed. Preferably, the amount of water added or present during hydrolysis is at least one third of the number of moles of all alkoxy groups on the silicon, more preferably one half of the number of moles of all alkoxy groups. It is less than 3 times. The product obtained by mixing the reactive silane compound and the particles under the condition where moisture is completely absent is a product in which the reactive silane compound is physically adsorbed on the particle surface.

  At the time of surface treatment, after subjecting the reactive silane compound to a separate hydrolysis operation, this is mixed with powder particles or solvent dispersion sol of the particles, followed by heating and stirring operation; hydrolysis of the reactive silane compound Can be selected in the presence of particles; or a method in which particles are surface-treated in the presence of other components such as a polymerization initiator. In this, the method of performing a hydrolysis of a reactive silane compound in presence of particle | grains is preferable. During the surface treatment, the temperature is preferably 0 ° C. or higher and 150 ° C. or lower, more preferably 20 ° C. or higher and 100 ° C. or lower. The processing time is usually in the range of 5 minutes to 24 hours.

When powdered metal oxide particles are used during the surface treatment, an organic solvent may be added for the purpose of smoothly and uniformly carrying out the reaction with the reactive silane compound. Examples of such organic solvents include alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, butyl acetate, ethyl lactate, and γ-butyrolactone. Esters such as ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; aromatic hydrocarbons such as benzene, toluene and xylene; amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone it can. Of these, methanol, isopropanol, butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene and xylene are preferred.
The amount of these solvents added is not particularly limited as long as it meets the purpose of carrying out the reaction smoothly and uniformly.

  When a solvent-dispersed sol is used as the particles, it can be produced by mixing at least a solvent-dispersed sol and a reactive silane compound. Here, an organic solvent which is uniformly compatible with water may be added for the purpose of ensuring the uniformity at the initial stage of the reaction and allowing the reaction to proceed smoothly.

In addition, an acid, a salt or a base may be added as a catalyst to promote the reaction during the surface treatment.
Examples of the acid include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; organic acids such as methanesulfonic acid, toluenesulfonic acid, phthalic acid, malonic acid, formic acid, acetic acid, and succinic acid; methacrylic acid, acrylic acid, and itacone An unsaturated organic acid such as an acid, as a salt, for example, an ammonium salt such as tetramethylammonium hydrochloride or tetrabutylammonium hydrochloride, and as a base, for example, aqueous ammonia, diethylamine, triethylamine, dibutylamine, Primary, secondary or tertiary aliphatic amines such as cyclohexylamine, aromatic amines such as pyridine, quaternary ammonium hydroxides such as sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, tetrabutylammonium hydroxide Etc. can be mentioned.
Among these, preferred examples of the acid include organic acids and unsaturated organic acids, and the base includes tertiary amine or quaternary ammonium hydroxide. The amount of these acids, salts or bases added is preferably 0.001 to 1.0 part by weight, more preferably 0.01 to 0.1 part by weight, based on 100 parts by weight of the reactive silane compound. Part.

In order to accelerate the reaction, it is also preferable to add a dehydrating agent.
As the dehydrating agent, inorganic compounds such as zeolite, anhydrous silica, and anhydrous alumina, and organic compounds such as methyl orthoformate, ethyl orthoformate, tetraethoxymethane, and tetrabutoxymethane can be used. Of these, organic compounds are preferable, and orthoesters such as methyl orthoformate and ethyl orthoformate are more preferable.
The amount of the reactive silane compound bonded to the particles is usually a thermogravimetric weight from 110 ° C. to 800 ° C. in air as a constant value of weight loss% when the dry powder is completely burned in air. It can be obtained by analysis.

The compounding amount of the component (A) in the curable composition of the present invention is usually 60 to 95% by weight, preferably 65 to 95% when the total solid content excluding the organic solvent (D) is 100% by weight. % By weight, more preferably 70 to 90% by weight. If the blending amount of component (A) is less than 60% by weight, the refractive index may be less than 1.6, and if it exceeds 95% by weight, applicability, transparency and curability may be reduced. .
In addition, the compounding quantity of a component (A) means solid content, and when a component (A) is used with the form of a dispersion liquid, the quantity of a dispersion medium is not included in the compounding quantity.

(B) Compound having structure represented by formula (b-1) or (b-2) In the composition of the present invention, the curable compound is represented by the following formula (b-1) or (b-2). A compound having a structure is used.

In formulas (b-1) and (b-2), R ¹ , R ³ and R ⁵ represent an alkylene group or alkylidene group having 1 to 4 carbon atoms, preferably a methylene group. R ² , R ⁴ and R ⁶ represent hydrogen or an alkyl group having 1 to 4 carbon atoms, preferably a methyl group.

Examples of the compound having the structure represented by the formula (b-1) or (b-2) include melamine compounds, urea compounds, benzoguanamine compounds, glycoluril compounds, and the like, and melamine compounds are preferable. By using a melamine compound as the curable compound, the storage stability of the curable composition can be improved. Further, it can be cured for a short time at a relatively low temperature, for example, 200 ° C. or less.
Melamine compounds are generally known as compounds having a skeleton in which a nitrogen atom is bonded to a triazine ring, and specific examples include melamine, alkylated melamine, methylol melamine, and alkoxylated methyl melamine. However, those having one or both of a methylol group and an alkoxylated methyl group in one molecule in total are preferably 2 or more. Specifically, methylolated melamine obtained by reacting melamine and formaldehyde under basic conditions, alkoxylated methylmelamine, or a derivative thereof is preferable, and particularly, the composition of the present invention has good storage stability. Alkoxylated methyl melamine is preferable in that it can be obtained and good reactivity can be obtained. There are no particular restrictions on the methylolated melamine and the alkoxylated methylmelamine used as the crosslinkable compound. Various resinous materials can be used.

  The melamine compound is most preferably a melamine compound having two or more methylol groups and alkoxylated methyl groups in the molecule. Among these melamine compounds, methylated melamines such as hexamethyletherified methylolmelamine compounds, hexabutyletherified methylolmelamine compounds, methylbutyl mixed etherified methylolmelamine compounds, methyletherified methylolmelamine compounds, butyletherified methylolmelamine compounds, etc. Compounds are more preferred.

  Examples of the compound having the structure represented by the general formula (b-1) or (b-2) include Cymel 300, 301, 303, 350, 370, 771, 325, 327, 703, 712, 272, 202. 207, 212, 253, 254, 506, 508, 1123, 1123-10, 1128, 1170, 1172, 1141, 1125-80, My Coat 102, 105, 106, 130 (all manufactured by Mitsui Cytec), etc. It is done.

  The compounding amount of the component (B) in the curable composition of the present invention is usually 1 to 40% by weight, preferably 3 to 30% when the total solid content excluding the organic solvent (D) is 100% by weight. % By weight, more preferably 5 to 20% by weight. Curing property will fall remarkably that the compounding quantity of a component (B) is less than 1 weight%. If it exceeds 40% by weight, the refractive index may be less than 1.60.

(C) Compound that generates acid by heating The compound that generates acid by heating component (C) is a curing catalyst, and is suitably used as long as it promotes the reaction of the component component (B). be able to. More specifically, aliphatic sulfonic acid, aliphatic sulfonate, aliphatic carboxylic acid, aliphatic carboxylate, aromatic sulfonic acid, aromatic sulfonate, aromatic carboxylic acid, aromatic carboxylate, Examples thereof include metal salts and phosphate esters. Of these, aliphatic sulfonates, aliphatic carboxylates, aromatic sulfonates, aromatic carboxylates, metal salts, phosphate esters, and the like are preferable. These compounds can be used singly or in combination of two or more.
Among these, aromatic sulfonates are most preferable because the curing rate of curable compounds such as methylated melamine compounds can be further improved.

  The compounding amount of the component (C) in the curable composition of the present invention is usually 0.01 to 20% by weight, preferably 0 when the total solid content excluding the organic solvent (D) is 100% by weight. 0.05 to 15% by weight, more preferably 0.1 to 10% by weight. When the compounding amount of the component (C) is less than 0.01% by weight, the effect of adding the curing catalyst is not exhibited. When it exceeds 10% by weight, the storage stability of the curable composition is lowered.

(D) Organic solvent An organic solvent is mix | blended in order to form the cured film of a thin film uniformly. Examples of the organic solvent include methyl isobutyl ketone, methyl ethyl ketone, methyl amyl ketone, cyclohexanone, methanol, ethanol, t-butanol, isopropanol, ethyl lactate, propylene glycol monomethyl ether, n-butanol, propylene glycol monomethyl ether acetate, etc. A combination of more than one species can be mentioned. A suitable solvent varies depending on the coating method of the curable composition, but when the spin coating method is used, cyclohexanone and propylene glycol monomethyl ether are preferable because they give good coating properties. In addition, an organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

Although the compounding quantity of an organic solvent (D) is not restrict | limited in particular, It is preferable to set it as 130-10,000 weight part in total with respect to 100 weight part of total amounts of solid content. When the addition amount is less than 100 parts by weight, it may be difficult to adjust the viscosity of the curable composition. On the other hand, when the addition amount exceeds 10,000 parts by weight, the storage stability of the curable composition may be reduced, and the viscosity may be excessively reduced, which may make handling difficult.
The addition amount of the organic solvent is more preferably 200 to 5,000 parts by weight, and further preferably 300 to 1,000 parts by weight.

(E) Additive The curable composition of the present invention includes a radical photopolymerization initiator, a radical polymerizable monomer, a photosensitizer, and a photoacid generator within a range that does not impair the purpose and effect of the present invention. , Polymerization inhibitor, polymerization initiator, leveling agent, wettability improver, surfactant, plasticizer, UV absorber, antioxidant, antistatic agent, silane coupling agent, inorganic filler, pigment, dye, etc. The additive may be further contained. The leveling agent is preferably a fluorine-based one that improves the applicability of the curable composition.

  The curable composition of the present invention is particularly useful as a material for forming a high refractive index layer of a solid-state imaging device, but can also be used as a material for an in-layer lens.

[Second Embodiment]
The second embodiment of the present invention is a cured film for a solid-state imaging device (hereinafter referred to as a high refractive index film) having a refractive index of 1.60 or more obtained by curing the curable composition of the present invention. The high refractive index film is installed between the base material layer and the microlens during the configuration of the solid-state imaging device. In addition to the high refractive index film, other layers such as a light collection efficiency improving layer and a flattening film are usually installed between the base material layer and the microlens.
A schematic diagram showing one embodiment of a solid-state imaging device having a cured film of the present invention is shown in FIG. The solid-state imaging device 1 includes a substrate 10, a light receiving unit 12, a high refractive index layer 14, a planarization layer 16, and a microlens (surface lens) 18.
FIG. 2 is a schematic view showing an embodiment of a solid-state imaging device having an intralayer lens made of the curable composition of the present invention. The solid-state imaging device 1 includes a substrate 10, a light receiving unit 12, a low refractive index layer 13, an intralayer lens 15, a planarization layer 16, and a microlens (surface lens) 18.
Since the light incident on the microlens (surface lens) 18 is refracted more strongly by the high refractive index layer 14 or the intralayer lens 15, the light collection efficiency can be increased.
In addition, the solid-state image sensor of this invention is not limited to FIG.1 and FIG.2.

The second embodiment will be specifically described below.
(1) High Refractive Index Material The curable composition used in the second embodiment is the same as the content of the first embodiment, and a specific description thereof is omitted here.

(2) Refractive index of cured film The refractive index of the cured film (high refractive index film) obtained by curing the curable composition of the present invention (the refractive index of Na-D line, measurement temperature 25 ° C.) is 1.60. That's it. When the refractive index is less than 1.60, the light collection efficiency to the light-receiving unit of the solid-state imaging device is lowered. The refractive index is more preferably 1.60 to 2.20, and still more preferably 1.65 to 2.20. If the refractive index exceeds 2.20, the types of materials that can be used may be excessively limited.
Further, when a plurality of high refractive index films are provided, at least one of them may have a refractive index within the above-described range. Therefore, other high refractive index films may have a refractive index of less than 1.60.

(3) Film thickness of cured film Next, the thickness of the high refractive index film will be described. The thickness of the high refractive index film is not particularly limited, but is preferably 50 to 30,000 nm, for example. If the thickness of the high refractive index film is less than 50 nm, the light collection efficiency on the solid-state imaging device light receiving part may not be sufficiently improved. On the other hand, if the thickness exceeds 30,000 nm, the amount of light transmitted through the high refractive index film may decrease, and the sensitivity of the solid-state imaging device may decrease. The thickness of the high refractive index film is more preferably from 100 to 10,000 nm, further preferably from 500 to 5,000 nm.

(4) Manufacturing method of cured film The cured film of this invention is formed by coating the said curable composition of this invention. Examples of such a coating method include a dipping method, a spray method, a die coating method, a slit coating method, a bar coating method, a roll coating method, a spin coating method, a curtain coating method, a gravure printing method, a silk screen method, and an ink jet method. Although the method can be used, the spin coating method is excellent in that a uniform cured film can be easily obtained.

Further, the means for curing the curable composition of the present invention is not particularly limited, but for example, it is preferably heat-cured after coating. In that case, it is preferable to heat at 30-200 degreeC for 1-180 minutes. By heating under these conditions, a cured film for a solid-state imaging device can be obtained without damaging the base material layer and the formed cured film. Preferably, it heats at 50-200 degreeC for 2-120 minutes, More preferably, it heats at 80-200 degreeC for 3 to 60 minutes.
The degree of curing of the curable composition of the present invention can be determined by, for example, infrared spectroscopic analysis of the amount of methylol group or alkoxylated methyl group of the melamine compound when a melamine compound is used as the curable compound (B). Alternatively, the gelation rate can be quantitatively confirmed by measuring using a Soxhlet extractor.
The curable composition of the present invention can be cured by irradiation with radiation, or can be cured by combining heat curing and radiation curing. In this case, the radiation refers to infrared rays, visible rays, ultraviolet rays, X-rays, electron beams, α rays, β rays, γ rays, and the like.

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to the description of these examples.

Production Example 1: Production of Zirconia Particle Sol (Aa) 300 parts of spherical zirconia fine powder (manufactured by Sumitomo Osaka Cement Co., Ltd., number average primary particle size 0.01 μm) is added to 700 parts of methyl ethyl ketone (MEK), and glass beads The dispersion was carried out for 168 hours, and the crow beads were removed to obtain 950 parts of methyl ethyl ketone zirconia sol (Aa). 2 g of the dispersed sol was weighed on an aluminum dish, dried on a hot plate at 120 ° C. for 1 hour, and weighed to determine the solid content, which was 30%. Moreover, as a result of observation of this solid matter by an electron microscope, the minor axis average particle diameter was 15 nm, the major axis average particle diameter was 20 nm, and the aspect ratio was 1.3.

Production Example 2: Production of Reactive Zirconia Particle Sol (A-1) 1.0 part of mercaptopropyltrimethoxysilane (manufactured by Toray Dow Corning Co., Ltd.), methyl ethyl ketone zirconia sol (Aa) prepared in Production Example 1 ( By mixing 309 parts of zirconia concentration 30%) and 0.1 parts of ion-exchanged water at 60 ° C. for 4 hours, 1.0 part of orthoformate methyl ester was added, and further heated and stirred at the same temperature for 1 hour. Reactive particles (dispersion (A-1)) were obtained. 2 g of this dispersion (A-1) was weighed on an aluminum dish, then dried on a hot plate at 120 ° C. for 1 hour and weighed to determine the solid content, which was 30%.

Production Example 3: Production of Reactive Zirconia Particle Sol (A-2) 1.3 parts of glycidoxypropyltrimethoxysilane (manufactured by Toray Dow Corning Co., Ltd.), methyl ethyl ketone zirconia sol (Aa) prepared in Production Example 1 ) (Zirconia concentration 30%) 309 parts and ion-exchanged water 0.1 parts mixed solution at 60 ° C. for 4 hours, then added 1.0 parts of orthoformate methyl ester, and further heated and stirred at the same temperature for 1 hour As a result, reactive particles (dispersion (A-2)) were obtained. 2 g of this dispersion (A-2) was weighed on an aluminum dish, dried on a hot plate at 120 ° C. for 1 hour and weighed to determine the solid content, which was 30%.

Example 1
In a container shielded from ultraviolet rays, 300.0 parts of reactive zirconia particle sol (A-1) prepared in Production Example 2 (90.0 parts of reactive zirconia particles), methylated melamine (product name: Cymel 300, Japan) 15.0 parts of Cytec Co., Ltd.) was added, and the mixture was stirred at 30 ° C. for 2 hours to obtain a uniform solution. This solution was concentrated under reduced pressure, and 155.9 parts of volatile matter was distilled off. Then, 12.5 parts of catalyst 4050 (aromatic sulfonic acid amine salt, manufactured by Nippon Cytec Co., Ltd.), Megafac F-445 (large 1 part of Nippon Ink Chemical Co., Ltd.), 2.4 parts of methyl ethyl ketone and 99.4 parts of cyclohexanone were added and stirred at 30 ° C. for 2 hours to obtain a composition. The solid content of this composition was measured and found to be 42%.

Examples 2-7 and Comparative Examples 1-3
Each composition was obtained in the same manner as in Example 1 except that the composition was changed as shown in Table 1.

[Evaluation of cured film]
(1) Preparation of cured film for evaluation (1-1) Cured film for evaluation of coatability, curability, and refractive index The film was coated on a silicon wafer using a spin coater. The spin coater was rotated at 300 rpm for 5 seconds and then at 2000 rpm for 40 seconds. Thereafter, using a hot plate, heating at 200 ° C. for 10 minutes was performed to obtain a cured coating film.

(1-2) Cured film for evaluation of light transmittance It was applied onto a glass wafer using a spin coater. The spin coater was rotated at 300 rpm for 5 seconds and then at 2000 rpm for 40 seconds. Thereafter, using a hot plate, heating at 200 ° C. for 10 minutes was performed to obtain a cured coating film.

(2) Evaluation method (2-1) Coating property The appearance of the coating film coated on the silicon wafer was visually confirmed and evaluated according to the following criteria. The obtained results are shown in Table 1.
○: The coating film is uniform and there is no color unevenness.
X: Color unevenness occurs in the coating surface.

(2-2) Curability The appearance after rubbing methyl ethyl ketone (MEK) on the coated and cured coating on the silicon wafer was visually confirmed and evaluated according to the following criteria. The obtained results are shown in Table 1.
○: No change is seen before and after MEK rubbing Δ: Scratches are seen after MEK rubbing ×: Peeling is seen after MEK rubbing

(2-3) Refractive index The refractive index in the wavelength of 589 nm was measured for the cured film formed on the silicon wafer by the spectral reflectance method. The obtained results are shown in Table 1.

(2-4) Light transmittance The total light transmittance of the cured film formed on the glass wafer was measured with a color haze meter and evaluated according to the following criteria. The total light transmittance was measured based on a glass wafer.
○: Total light transmittance is 95% or more Δ: Total light transmittance is 90% or more and less than 95% ×: Total light transmittance is less than 90%

The trade names described in Table 1 mean the following.
Zirconia particles (Aa): Production Example 1
Reactive zirconia particles (A-1): Production Example 2
Reactive zirconia particles (A-2): Production Example 3
Cymel 300: Methoxylated methylmelamine, manufactured by Nippon Cytec Co., Ltd. cat4050: Aromatic sulfonic acid amine salt, manufactured by Nippon Cytec Co., Ltd. F445: Fluorine-based leveling agent, MegaFuck F-445, Dainippon Ink & Chemicals, Inc. Manufactured MEK: Methyl ethyl ketone PGMEA: Propylene glycol monomethyl ether

  From the results of Table 1, by using zirconia particles surface-treated with an alkoxysilane compound having a group capable of reacting with a melamine compound, the refractive index is as high as 1.74 and the light transmittance is excellent. It turns out that applicability | paintability and sclerosis | hardenability are also favorable.

The curable composition of the present invention is useful as a material for forming a high refractive index layer in a solid-state imaging device.
A solid-state imaging device including a cured film obtained by using the curable composition of the present invention is particularly useful for an optical system mechanism such as a camera using various microlens arrays.

It is a schematic diagram which shows one Embodiment of the solid-state image sensor of this invention. It is a schematic diagram which shows another embodiment of the solid-state image sensor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid-state image sensor 10 Board | substrate 12 Light-receiving part 13 Low-refractive-index layer 14 High-refractive-index layer 15 In-layer lens 16 Planarizing layer 18 Micro lens (surface lens)

Claims (8)

The following components (A) to (D):
(A) by an alkoxysilane compound having as a main component an oxide of one or more metal elements selected from the group consisting of aluminum, titanium, zirconium, tin, antimony and zinc, and having a group capable of reacting with the following component (B) Surface-treated particles (B) A compound having a structure represented by the following general formula (b-1) or (b-2)

(In formulas (b-1) and (b-2), R ¹ , R ³ and R ⁵ represent an alkylene group or alkylidene group having 1 to 4 carbon atoms, and R ² , R ⁴ and R ⁶ represent hydrogen or carbon. Represents an alkyl group of formulas 1 to 4.)
(C) The curable composition for solid-state image sensors containing the compound (D) organic solvent which generate | occur | produces an acid by heating.   The alkoxysilane compound having a group capable of reacting with the component (B) is a trialkoxysilane compound having one or more groups selected from the group consisting of thiol groups, hydroxyl groups, epoxy groups, amino groups and isocyanate groups. Item 2. A curable composition for a solid-state imaging device according to Item 1.   The curable composition for a solid-state imaging device according to claim 1, wherein the component (B) is an alkoxymethylated melamine compound.   The component (C) is one or more compounds selected from the group consisting of aliphatic sulfonates, aliphatic carboxylates, aromatic sulfonates, aromatic carboxylates, metal salts and phosphate esters. Item 4. The curable composition for a solid-state imaging device according to any one of Items 1 to 3.   The curable composition for a solid-state imaging device according to any one of claims 1 to 4, wherein the organic solvent (D) contains one or more solvents selected from the group consisting of propylene glycol monomethyl ether and cyclohexanone.   A cured film for a solid-state imaging device having a refractive index of 1.60 or more obtained by curing the curable composition for a solid-state imaging device according to any one of claims 1 to 5.   After applying the curable composition for solid-state imaging devices according to any one of claims 1 to 6 by a spin coating method to form a coating film of the composition, the coating film is irradiated with heat or radiation. The manufacturing method of the cured film for solid-state image sensors of Claim 6 which has the process of hardening | curing. A solid-state imaging device including a light receiving portion, the cured film according to claim 7, and a microlens in this order.

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