JP2005228888A - Curing composition for solid-state imaging device, and the solid-state imaging device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curing composition for a solid-state imaging device which obtains a curing film at a high refractive index and superior light resistance, and to provide the curing film for the solid-state imaging device having superior antireflection properties. <P>SOLUTION: The curing composition contains (1) titanium oxide particles of 100 parts by weight coated with oxide of one or more metal elements, selected from among a group consisting of silicon, aluminium, titanium, zirconium, tin, antimony and zinc; (2) a curing compound of 1 to 150 parts by weight; and (3) a curing catalyst of 0.1 to 100 parts by weight. The solid-state imaging device 10 has a laminate, containing the curing film formed by curing this curing composition under a microlens, and can effectively be used for a use field of an optical system mechanism of a camera and the like, by using various microlens arrays. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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. More specifically, the present invention relates to a curable composition for a solid-state imaging device having a refractive index of 1.60 or more and a cured film excellent in light resistance and a cured film for a solid-state imaging device excellent in antireflection using the same. .

FIG. 1 is a sectional view of a conventional solid-state imaging device. As shown in FIG. 1, a light receiving unit 2 and a transfer unit 3, a silicon oxide film 4, a polysilicon electrode 5, a tungsten silicide 6, a BPSG film 7, and a light shielding metal 8 are sequentially provided on an N-type semiconductor substrate 1. A planarizing film 9 is provided on the top with an acrylic resin or the like. A microlens 10 is formed on the planarizing film 9.
Patent Document 1 describes that the planarizing film 9 is formed of a polyimide resin having a refractive index larger than that of the microlens 10. 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 below the microlens and having a higher refractive index has been demanded.

  On the other hand, as a metal oxide particle, a high refractive index material using zirconium oxide and having a refractive index of about 1.7 and improved storage stability is 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.
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.

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

The present invention provides a curable composition for a solid-state imaging device having a high refractive index and a cured film excellent in light resistance, and a cured film for a solid-state imaging device having excellent antireflection properties using the same. With the goal.
As a result of intensive studies by the inventors of the present invention, (1) 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 (Hereinafter referred to as “coated titanium oxide particles”), (2) a curable compound, and (3) a curing catalyst mixed in an addition amount within a predetermined range, or ( 4) It has been found that the above-mentioned problems can be solved by using, as a high refractive index material, a curable composition in which a hydroxyl group-containing compound is mixed in an addition amount within a predetermined range.

The solid-state imaging device of the present invention is composed of a combination of a microlens and a laminate including a cured film of the curable composition of the present invention below the microlens. The laminated body below the microlens can function as a light collection efficiency improving layer, a flattening layer, or the like.
According to the first aspect of the present invention, (1) 100 parts by weight of coated titanium oxide particles, (2) 1 to 300 parts by weight of a curable compound, and (3) 0.1 to 30 parts by weight of a curing catalyst. A curable composition for a solid-state imaging device is provided. This curable composition preferably contains 1 to 150 parts by weight of (4) a hydroxyl group-containing compound.

(1) By using the coated titanium oxide particles, the refractive index of the cured film can be adjusted to 1.60 or more with a relatively small amount of addition. This coated titanium oxide particle has the advantage of high transparency (low coloration).
Moreover, by configuring the curable composition in this way, a cured film (high refractive index film) having a refractive index of 1.60 or more and excellent light resistance can be obtained.

  In the curable composition of the present invention, (2) the curable compound is a melamine compound, (3) the curing catalyst is an aromatic sulfonic acid or an aromatic sulfonate, and (4) the hydroxyl group-containing compound is polyvinyl. A butyral resin is preferred.

(2) 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.
In addition, (4) using a polyvinyl butyral resin as the hydroxyl group-containing compound facilitates uniform dispersion of the coated titanium oxide particles when preparing the curable composition. Moreover, the mechanical characteristics of the obtained high refractive index film can be improved.

  The curable composition preferably further contains 100 to 10,000 parts by weight of an organic solvent.

According to the 2nd aspect of this invention, the cured film for solid-state image sensors with a refractive index of 1.60 or more formed by hardening said curable composition is provided.
Since this cured film has a high refractive index, it is possible to increase the light collection efficiency of the solid-state imaging device and improve the sensitivity.

  According to the third aspect of the present invention, after applying the curable composition for a solid-state imaging device by a spin coating method to form a coating film of the composition, the coating film is irradiated with heat or radiation. There is provided a method for producing the above-mentioned cured film, which comprises a step of curing.

According to the 4th aspect of this invention, the solid-state image sensor which has a base material layer, said hardened | cured film (high refractive index film | membrane), and a micro lens in this order is provided.
By including such a high refractive index film, the light collected by the microlens can be efficiently guided to the light receiving element.

  According to the curable composition of the present invention, a cured film having a high refractive index and excellent light resistance can be obtained.

  An embodiment (first embodiment) relating to the curable composition for a solid-state imaging device of the present invention and an embodiment (second embodiment) relating to the cured film for the solid-state imaging device will be specifically described.

[First Embodiment]
The curable composition of the present invention contains (1) 100 parts by weight of coated titanium oxide particles, (2) 1 to 300 parts by weight of a curable compound, and (3) 0.1 to 30 parts by weight of a curing catalyst. .

(1) Coated titanium oxide particles Coated titanium 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. is there. Here, the method of coating the titanium oxide particles is not particularly limited. For example, “Titanium oxide physical properties and applied technology” (manufactured by Kiyono Manabu) Gihodo Publishing p. 28-31 (1991), a method in which titanium oxide particles are coated with a metal hydroxide by treatment in an aqueous solution of a predetermined metal salt and then fired. In this case, most of the metal hydroxide becomes a metal oxide by firing. Therefore, in the present invention, the coated titanium oxide particles is a concept including an aspect in which the metal hydroxide remains in the metal oxide forming the coated portion.

  The coating is not necessarily limited to an embodiment in which the entire surface of the titanium oxide particles is covered with the metal oxide, and may be dense or porous. The coated titanium oxide particles are not limited to particles having a coating layer that is clearly separated from the titanium oxide particles, and the metal oxide or metal hydroxide is mainly present near the outer shell of the particles. In addition, particles that do not form a layer in which the coating layer and the titanium oxide particles are clearly separated are also included.

The coating can be performed with two or more metal element oxides among the above metal element oxides. In this case, the coating with each metal oxide may form a coating layer, or two or more metal element oxides may be co-precipitated to form one coating layer.
When the metal oxide contains zirconium oxide (zirconia), a high refractive index can be obtained with a small amount of added particles, and thus a cured film having a high refractive index can be obtained without impairing the transparency of the cured film. Is preferable.

The number average particle diameter of the coated titanium oxide particles (the 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 coated titanium oxide particles. In addition, the coated titanium oxide particles 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 0.01 to 0.08 μm, and further preferably 0.02 to 0.05 μm.
By using such coated titanium oxide particles, the photocatalytic activity of titanium oxide can be suppressed, and decomposition of the cured product can be suppressed. As a result, a cured film having a high refractive index and excellent light resistance can be obtained.

(2) Curable compound Examples of the curable compound include one kind of melamine compound, urea compound, guanamine compound, phenol compound, epoxy compound, isocyanate compound, polybasic acid, or a combination of two or more kinds.
Of these, a melamine compound having two or more methylol groups and / or alkoxylated methyl groups in the molecule is most preferred from the viewpoint of relatively excellent storage stability and curing at a relatively low temperature. 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.

  The addition amount of the curable compound is 1 to 300 parts by weight, preferably 10 to 250 parts by weight, with respect to 100 parts by weight of the coated titanium oxide particles. When the addition amount is less than 1 part by weight, the mechanical strength of the coating film decreases. On the other hand, when the addition amount exceeds 300 parts by weight, the storage stability of the curable composition is lowered.

(3) Curing catalyst Any curing catalyst can be used as long as it accelerates the reaction of the curable compound. More specifically, aliphatic sulfonic acid, aliphatic sulfonate, aliphatic carboxylic acid, aliphatic carboxylate, aromatic sulfonic acid, aromatic sulfonate, aromatic carboxylic acid, aromatic carboxylate, One kind alone or a combination of two or more kinds such as metal salts and phosphoric acid esters may be mentioned.
Of these, aromatic sulfonic acids are most preferable because the curing rate of curable compounds such as methylated melamine compounds can be further improved.

  The addition amount of the curing catalyst is 0.1 to 30 parts by weight, preferably 0.5 to 30 parts by weight, and more preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the coated titanium oxide particles. When the addition amount is less than 0.1 parts by weight, the effect of adding the curing catalyst is not exhibited. On the other hand, when the addition amount exceeds 30 parts by weight, the storage stability of the curable composition is lowered.

(4) Hydroxyl-containing compound It is desirable to add a hydroxyl-containing compound to the curable composition of the present invention. As the hydroxyl group-containing compound, any polymer having a hydroxyl group in the molecule can be preferably used. More specifically, a single type of polyvinyl acetal resin (polyvinyl butyral resin, polyvinyl formal resin), polyvinyl alcohol resin, polyacrylic resin, polyphenolic resin, phenoxy resin, or a combination of two or more types can be given.
Of these, polyvinyl butyral resins (including modified polyvinyl butyral resins) are most preferred because of excellent mechanical properties and relatively easy uniform dispersion of the coated titanium oxide particles. Among polyvinyl butyral resins, those having an average degree of polymerization of 1,000 or less, a polyvinyl alcohol unit in one molecule of 18% by weight or more, and a glass transition point of 70 ° C. or more. More preferred.

The amount of the hydroxyl group-containing compound added is preferably 1 to 150 parts by weight with respect to 100 parts by weight of the coated titanium oxide particles. If it is 1 part by weight or more, the mechanical properties are improved. On the other hand, if the addition amount is 150 parts by weight or less, a relatively sufficient amount of coated titanium oxide particles can be secured, and sufficient refractive index characteristics of the cured film after curing can be obtained.
The amount of the hydroxyl group-containing compound added is more preferably 1 to 50 parts by weight, still more preferably 1 to 30 parts by weight.

(5) Organic solvent It is preferable to add an organic solvent in the curable composition. By adding an organic solvent, a thin cured film can be formed uniformly. Examples of such an organic solvent include one kind alone or a combination of two or more kinds such as methyl isobutyl ketone, methyl ethyl ketone, methanol, ethanol, t-butanol, isopropanol, ethyl lactate, propylene glycol monomethyl ether, and n-butanol. The suitable solvent varies depending on the application method of the curable composition. When using a dip method or a casting method, one or a combination of two or more of methyl isobutyl ketone, methyl ethyl ketone, methanol, ethanol, t-butanol, isopropanol and the like is preferable. On the other hand, when the spin coating method is used, ethyl lactate, propylene glycol monomethyl ether, and n-butanol are preferable because they give good coatability.

The addition amount of the organic solvent is not particularly limited, but is preferably 100 to 10,000 parts by weight with respect to 100 parts by weight of the coated titanium oxide particles. 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 20,000 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 300 to 10,000 parts by weight, and further preferably 500 to 5,000 parts by weight.

(6) Additives In the curable composition, radical photopolymerization initiator, radical polymerizable monomer, photosensitizer, photoacid generator, polymerization prohibition, as long as the object and effect of the present invention are not impaired. Additives, polymerization initiators, leveling agents, wettability improvers, surfactants, plasticizers, UV absorbers, antioxidants, antistatic agents, silane coupling agents, inorganic fillers, pigments, dyes, etc. Can further be contained.

[Second Embodiment]
The second embodiment of the present invention is a solid imaging element cured film (hereinafter referred to as “high refractive index film”) having a refractive index of 1.60 or more obtained by curing a curable composition for a solid imaging element. In the configuration of the solid-state imaging device, the high refractive index film is installed on the base material layer and between the microlens, and in addition to the high refractive index film, for example, a collection is provided between the base material layer and the microlens. In general, other layers such as a light efficiency improving layer and a planarizing film are provided, and 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, the other high refractive index film 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 for a solid-state imaging device of the present invention is formed by coating the curable composition described above. 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 for a solid-state imaging device 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 50-180 degreeC for 2-120 minutes, More preferably, it heats at 80-150 degreeC for 5-60 minutes.
The degree of curing of the curable composition for a solid-state imaging device of the present invention is 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. Alternatively, the gelation rate can be quantitatively confirmed by measuring using a Soxhlet extractor.
The curable composition for a solid-state imaging device 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
[Preparation of Coated Titanium Oxide Particle Dispersion-1]
Silica-coated titanium oxide fine powder 3.5 parts by weight, Denka Butyral # 2000-L (manufactured by Denki Kagaku Kogyo Co., Ltd., polyvinyl butyral resin, average polymerization degree: about 300, polyvinyl alcohol unit in one molecule: 21 weights %, Glass transition point (Tg): 71 ° C., PVB # 2000L 0.6 parts by weight, methyl isobutyl ketone (MIBK) 12 parts by weight, t-butanol 8 parts by weight, and dispersed for 10 hours with glass beads. Then, the glass beads were removed to obtain 24 parts by weight of silica-coated titanium oxide particle dispersion-1. The obtained coated titanium oxide particle dispersion-1 was weighed on an aluminum dish and dried on a hot plate at 120 ° C. for 1 hour to obtain a total solid content concentration of 17% by weight. Further, this silica-coated titanium oxide particle dispersion-1 was weighed in a magnetic crucible, pre-dried on a hot plate at 80 ° C. for 30 minutes, and then baked in a muffle furnace at 750 ° C. for 1 hour. When the inorganic content in the total solid content was determined from the amount of inorganic residue and the total solid content concentration, it was 85% by weight.

Production Example 2
[Preparation of coated titanium oxide particle dispersion-2]
Silica-coated titanium oxide fine powder 3.5 parts by weight, ethylene oxide-propylene oxide copolymer (average degree of polymerization: about 20) 0.6 parts by weight, MIBK 12 parts by weight, t-butanol 8 parts by weight, glass The beads were dispersed for 10 hours, and the glass beads were removed to obtain 24 parts by weight of coated titanium oxide particle dispersion-2. When the total solid content concentration and the inorganic content in the total solid content of the coated titanium oxide particle dispersion-2 were measured in the same manner as in Production Example 1, they were 17% by weight and 85% by weight, respectively.

Production Example 3
[Preparation of coated titanium oxide particle dispersion-3]
Zirconia and alumina-coated titanium oxide fine powder 3.5 parts by weight, ethylene oxide-propylene oxide copolymer (average degree of polymerization: about 20) 0.6 parts by weight, propylene glycol monomethyl ether 20 parts by weight, glass beads For 10 hours to remove the glass beads to obtain 24 parts by weight of coated titanium oxide particle dispersion-3. When the total solid content concentration and the inorganic content in the total solid content of this coated titanium oxide particle dispersion-3 were measured in the same manner as in Production Example 1, they were 17% by weight and 85% by weight, respectively.

Comparative production example 1
[Preparation of rutile-type titanium oxide particle dispersion]
A rutile-type titanium oxide particle dispersion was prepared in the same manner as in Production Example 2 except that rutile-type titanium oxide fine powder was used instead of silica-coated titanium oxide fine powder. When the total solid content concentration and the inorganic content in the total solid content of the rutile-type titanium oxide particle dispersion were measured in the same manner as in Production Example 1, they were 17% by weight and 85% by weight, respectively.

Comparative production example 2
[Preparation of anatase-type titanium oxide particle dispersion]
An anatase-type titanium oxide particle dispersion was prepared in the same manner as in Comparative Production Example 1 except that anatase-type titanium oxide fine powder was used instead of the rutile-type titanium oxide fine powder. When the total solid content concentration and the inorganic content in the total solid content of this anatase-type titanium oxide particle dispersion were measured in the same manner as in Production Example 1, they were 17% by weight and 85% by weight, respectively.

  Hereinafter, preparation examples of the curable composition (high refractive index curable composition) of the present invention are shown in Examples 1 to 11 and Comparative Examples 1 to 4.

Example 1
In the container, silica-coated titanium oxide particle dispersion-1 prepared in Production Example 1: 24 parts by weight (3.5 parts by weight as silica-coated titanium oxide particles, 0.6 parts by weight as PVB # 2000L), Cymel 303 ( Curable compound, methylated methylmelamine, manufactured by Mitsui Cytec Co., Ltd .: 0.7 parts by weight, catalyst 4050 (cat 4050) (curing catalyst, aromatic sulfonic acid compound, solid content concentration 32% by weight, Mitsui Cytec Co., Ltd. )): 0.16 parts by weight, MIBK: 45 parts by weight, and t-butanol: 30 parts by weight, respectively, to obtain a curable composition of a uniform solution. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 2
In the container, silica-coated titanium oxide particle dispersion prepared in Production Example-2: 10 parts by weight (1.5 parts by weight as silica-coated titanium oxide particles), PVB # 2000L: 1.6 parts by weight, Cymel 303: 1.6 parts by weight, cat 4050 (solid content concentration 32% by weight): 0.32 parts by weight, MIBK: 52 parts by weight, and t-butanol: 35 parts by weight were added to obtain a curable composition of a uniform solution. . When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 3
A uniform solution curable composition was obtained in the same manner as in Example 2 except that PVB # 2000L was not added and the amount of Cymel 303 added was 3.2 parts by weight. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 4
In the container, silica-coated titanium oxide particle dispersion prepared in Production Example-2: 24 parts by weight (3.5 parts by weight as silica-coated titanium oxide particles), PVB # 2000L: 0.35 parts by weight, Cymel 303: 0.35 parts by weight, cat 4050 (solid content concentration 32% by weight): 0.16 parts by weight, MIBK: 45 parts by weight and t-butanol: 30 parts by weight were added to obtain a curable composition of a uniform solution. . When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 5
A curable composition of a uniform solution was obtained in the same manner as in Example 4 except that PVB # 2000L was not added and the amount of Cymel 303 added was 0.7 parts by weight. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 6
In the container, the silica-coated titanium oxide particle dispersion prepared in Production Example-2: 36 parts by weight (5.2 parts by weight as silica-coated titanium oxide particles), PVB # 2000L: 0.1 parts by weight, Cymel 303: 0.1 parts by weight, cat 4050 (solid content concentration 32% by weight): 0.032 parts by weight, MIBK: 39 parts by weight, and t-butanol: 26 parts by weight were added to obtain a curable composition having a uniform solution. . When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 7
A curable composition of a uniform solution was obtained in the same manner as in Example 6 except that PVB # 2000L was not added and the amount of Cymel 303 added was 0.2 parts by weight. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 8
In the container, coated titanium oxide particle dispersion prepared in Production Example 3: 40 parts by weight (5.7 parts by weight as titanium oxide coated with zirconia and alumina, and 0.99 parts by weight as ethylene oxide-propylene oxide) Cymel 303: 1.15 parts by weight, cat 4050 (solid content concentration: 32% by weight): 0.26 parts by weight, and 59 parts by weight of ethyl lactate were added to obtain a curable composition of a uniform solution. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 8% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 9
A curable composition was obtained in the same manner as in Example 8 except that 59 parts by weight of propylene glycol monomethyl ether was used instead of ethyl lactate as a diluent solvent. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 8% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 10
In the container, zirconia and alumina-coated titanium oxide particle dispersion prepared in Production Example 3: 40 parts by weight (5.7 parts by weight as zirconia and alumina-coated titanium oxide, 0 as ethylene oxide-propylene oxide) 99 parts by weight), Cymel 303: 1.15 parts by weight, cat 4050 (solid content concentration 32% by weight): 0.26 parts by weight, and 59 parts by weight of propylene glycol monomethyl ether acetate, respectively, and a curable composition of a uniform solution. I got a thing. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 8% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Example 11
A curable composition was obtained in the same manner as in Example 10 except that 59 parts by weight of methyl isobutyl ketone was used in place of propylene glycol monomethyl ether acetate as a diluent solvent. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 8% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Comparative Example 1
A curable composition of a uniform solution was obtained in the same manner as in Example 4 except that the rutile-type titanium oxide particle dispersion prepared in Comparative Production Example 1 was used. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Comparative Example 2
A uniform solution curable composition was obtained in the same manner as in Comparative Example 1 except that PVB # 2000L was not added and the amount of Cymel 303 added was 0.7 parts by weight. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Comparative Example 3
A uniform solution curable composition was obtained in the same manner as in Example 4 except that the anatase-type titanium oxide particle dispersion prepared in Comparative Production Example 2 was used. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

Comparative Example 4
A uniform curable composition of a solution was obtained in the same manner as in Comparative Example 3 except that PVB # 2000L was not added and the amount of Cymel 303 added was 0.7 parts by weight. When the total solid content concentration in the curable composition was measured in the same manner as in Production Example 1, it was 5% by weight. Moreover, the viscosity (25 degreeC) of this curable composition was 2 mPa * s.

  Tables 1 and 2 show the compositions, total solids concentrations and viscosities of the curable compositions of Examples 1 to 11 and Comparative Examples 1 to 4, respectively.

  Hereinafter, the manufacture example of the cured film (high refractive index cured film) of this invention is shown in Examples 12-22 and Comparative Examples 5-8.

Examples 12-22
[Evaluation of cured film]
(1) Preparation of cured film for evaluation (1-1) Cured film for evaluation of refractive index The cured film for evaluation of refractive index is obtained by a method suitable for the organic solvent used in each curable composition. It was prepared by coating.
That is, about the curable composition of Examples 12-18, after drying the curable composition prepared in each Example shown in Table 1 on a silicon wafer using a wire bar coater (# 3). (Refer to the “bar coating” method in Tables 3 and 4), and then heated in an oven at 120 ° C. for 10 minutes for high refraction. A rate cured film was obtained.
About the curable composition of Examples 19-22, it apply | coated using the spin coater (Mikasa Co., Ltd. product 1H-360S type | mold). The spin coater was rotated at 300 rpm for 5 seconds and then at 2000 rpm for 20 seconds. A silicon wafer was spin-coated so that the thickness after drying was about 0.1 μm (referred to as “spin coating” in Table 3), and then using an oven at 120 ° C. for 10 minutes. Heated to obtain a high refractive index cured film.
The refractive index of the obtained high refractive index cured film was measured under the following condition (2-1). The results are shown in Table 3.
(1-2) Cured film for evaluation of turbidity, light resistance and applicability The cured film for evaluation of turbidity, light resistance and applicability is curable by a method suitable for the organic solvent used in each curable composition. The composition was applied and prepared.
That is, for the curable compositions of Examples 12 to 18, the curable compositions prepared in each Example shown in Table 1 were dried using a wire bar coater (# 3), and the thickness after drying was about 0. .1 μm, coated on an easy-adhesion treated or untreated surface of a single-sided easy-adhesive polyethylene terephthalate (PET) film A4100 (manufactured by Toyobo Co., Ltd., film thickness 188 μm), in an oven at 120 ° C. The film was dried for 10 minutes to obtain a high refractive index cured film.
About the curable composition of Examples 19-22, it carried out similarly to (1-1), and obtained the high refractive index cured film.
The turbidity, light resistance, and coatability of the obtained high refractive index cured film were evaluated according to the following criteria (2-2) to (2-4). The results are shown in Table 3.

(2) Evaluation method (2-1) Refractive index About each obtained cured film, the refractive index (nD25) in wavelength 589nm in 25 degreeC was measured using the ellipsometer.

(2-2) Turbidity Turbidity (Haze value) of the obtained cured film was measured using a Haze meter and evaluated according to the following criteria.
○: Haze value is 2% or less.
Δ: Haze value is 3% or less.
X: Haze value is 5% or more.

(2-3) Light resistance The obtained cured film was irradiated with ultraviolet rays for 150 hours using a QUV accelerated weathering tester (manufactured by Q-Panel), and the appearance was visually observed. It was evaluated with.
○: In the light resistance test, there is no whitening of the coating film, and no peeling occurs when rubbed with a nail. X: In the light resistance test, whitening of the coating film is observed or it is easily peeled off when rubbed with a nail.

(2-4) Applicability The applicability was evaluated according to the following criteria based on the appearance of the cured film.
○: The appearance of the cured film is transparent and there is almost no color unevenness.
X: The appearance of the cured film is opaque or has uneven color.

  In place of the zirconia and alumina-coated titanium oxide fine powder (coated titanium oxide particle dispersion-3) used in Example 19, the silica-coated titanium oxide fine powder (coated titanium oxide particle dispersion- 2) was used to produce a curable composition, and a cured film was produced using the curable composition in the same manner as in Example 19. Example using titanium oxide fine powder coated with zirconia and alumina In No. 19, the refractive index of the cured film was 1.89, whereas it was 1.85 when silica-coated titanium oxide fine powder was used.

Comparative Examples 5-8
A cured film was obtained in the same manner as in Example 12 except that each of the high refractive index curable compositions prepared in Comparative Examples 1 to 4 was used. The evaluation results are shown in Table 4.

  A solid-state imaging device including a cured film obtained by using the curable composition of the present invention can be usefully used for an optical system mechanism such as a camera using various microlens arrays.

A sectional view of a conventional solid-state imaging device is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Light-receiving part 3 Transfer part 4 Silicon oxide film 5 Polysilicon electrode 6 Tungsten silicide 7 BPSG film 8 Light shielding metal 9 Flattening film 10 Microlens

Claims (8)

(1) 100 parts by weight of 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;
(2) 1 to 300 parts by weight of a curable compound,
(3) A curable composition for a solid-state imaging device, comprising 0.1 to 30 parts by weight of a curing catalyst.   Furthermore, the curable composition for solid-state image sensors of Claim 1 containing 1-150 weight part of hydroxyl-containing compounds.   The curable composition for a solid-state imaging device according to claim 1, wherein the curable compound is a melamine compound.   The curable composition for a solid-state imaging device according to any one of claims 1 to 3, further comprising 100 to 10,000 parts by weight of an organic solvent.   The curable composition for a solid-state imaging device according to claim 4, wherein the organic solvent contains one or more solvents selected from the group consisting of ethyl lactate, propylene glycol monomethyl ether, and n-butanol.   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 image sensors as described in any one of Claims 1-5 by a spin coat method, and forming the coating film of this composition, this coating film is irradiated with a heating or a radiation. The manufacturing method of the cured film for solid-state image sensors of Claim 6 which has the process of hardening | curing.   The solid-state image sensor which contains a base material layer, the cured film of Claim 6, and a micro lens in this order.

Images