JP2003195072A - Optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a patterned optical waveguide which has an excellent anti- heat cycle characteristics and optical characteristics and is composed of a lower clad layer, a core portion, and an upper clad layer, either one of layers of which is formed with a hardened material containing siloxane. <P>SOLUTION: The patterned optical waveguide is composed of a lower clad layer, a core portion, and an upper clad layer, and either one of them is formed with a silica-based compound. The optical waveguide is characterized by the fact that the linear expansion coefficient of the core portion β is 150 ppm/K or smaller and the difference in linear expansion coefficient Δβ of the core clad portion and the clad layers is 50 ppm/K or smaller. <P>COPYRIGHT: (C)2003,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a lower cladding layer,
The present invention relates to a patterned optical waveguide comprising a core portion and an upper cladding layer, any one of which is formed from a cured product containing siloxane. More specifically, the heat cycle resistance and optical characteristics are characterized in that the linear expansion coefficient β of the core portion is 150 ppm or less, and the difference Δβ between the linear expansion coefficient of the core portion and the cladding layer is 50 ppm or less. It relates to a good optical waveguide.

[0002]

2. Description of the Related Art In the era of multimedia, optical waveguides have attracted attention as optical transmission media due to demands for large-capacity and high-speed information processing in optical communication systems and computers. Optical waveguides used for such purposes are:
In addition to good optical characteristics such as transmission loss, its performance is stable for a long time without affecting the external environment.
It is desired that the optical waveguide having a fine and complicated shape be manufactured with a low energy, a short time, and a small number of steps without causing environmental pollution. A typical example of such an optical waveguide is a silica-based waveguide, which is generally manufactured by the following steps. A lower cladding layer made of a glass film is formed on a silicon substrate by a technique such as a flame deposition method (FHD) or a CVD method. An inorganic thin film having a different refractive index from the lower clad layer is formed on the lower clad layer, and the thin film is patterned by using a reactive ion etching (RIE) to form a core portion. Further, an upper clad layer is formed by a flame deposition method. However, such a method of manufacturing a silica-based waveguide is said to have good optical characteristics and durability, but requires special equipment for the manufacture, and requires a large number of complicated steps and manufacturing time. It took a long time and the yield was low. To solve these problems, several techniques using a curable composition have been proposed in recent years for the purpose of shortening the manufacturing time of the optical waveguide, reducing the number of steps, and improving the yield. For example, as a technique using a photosensitive optical waveguide material, for example, in JP-A-10-254140, a photocurable composition comprising a condensate of a hydrolyzable silane, a photoacid generator, a dehydrating agent, In 2000-180643, a photosensitive composition comprising an epoxy group-containing silane compound, an organic oligomer, and a polymerization initiator; in JP-A-2001-288364, a condensate of a hydrolyzable silane, a photoacid generator, and a basic acid diffusion A radiation curable composition comprising a control agent is disclosed. These techniques disclose that the use of a photosensitive composition enhances the productivity of an optical waveguide and enables high-precision pattern formation.However, heat cycle resistance, which is an index of durability in a practical environment, is disclosed. An optical waveguide satisfying the characteristics and optical characteristics is not disclosed.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical waveguide having excellent heat cycle resistance and optical characteristics.

[0004]

As a result of intensive studies aimed at solving the above-mentioned problems of the prior art, the inventors have come to invent the optical waveguide shown in the present invention. That is, the present invention is a patterned optical waveguide comprising a lower cladding layer, a core portion, and an upper cladding layer, any one of which is formed from a silica-based compound. It is an object of the present invention to provide an optical waveguide characterized in that β is 150 ppm / K or less and a difference Δβ in linear expansion coefficient between the core portion and the cladding layer is 50 ppm / K or less. Hereinafter, each component and embodiment of the present invention will be specifically described with reference to the drawings as appropriate. The present invention comprises a lower cladding layer, a core portion, and an upper cladding layer.
In a patterned optical waveguide in which the layer is formed from a silica-based compound, the linear expansion coefficient β of the core portion is 150 ppm / K or less, and the difference Δ in the linear expansion coefficient between the core portion and the cladding layer Δ
An optical waveguide characterized in that β is 50 ppm / K or less.

[0005] In the present invention, the coefficient of linear expansion (hereinafter abbreviated as β)
-20 at atmospheric pressure by thermomechanical analysis (TMA)
Determined in the range of ° C to 80 ° C and defined as a value expressed in ppm / K. Β of the core portion in the optical waveguide of the present invention is 15
0 ppm / K or less, preferably 100 ppm / K or less.
When β in the core portion exceeds 150 ppm / K, heat cycle resistance decreases. Further, the difference Δβ between the coefficient of linear expansion of the core portion and the cladding layer is desirably 50 ppm / K or less, preferably 20 ppm / K or less, and more preferably 10 ppm / K or less. Δβ is 5
If it exceeds 0 ppm / K, the heat cycle resistance similarly decreases. Further, the lower clad layer and the upper clad layer may be the same or different curable materials, and may be manufactured by different processes, for example, heat curing, light curing, and the like.

In the present invention, in order to further improve the heat cycle resistance, the coefficient of linear expansion of the substrate is preferably 100 ppm / K or less, more preferably 50 ppm / K. By configuring the optical waveguide in this way, it is possible to reduce the deterioration of the optical characteristics with respect to the temperature change. As is clear from the examples and comparative examples of the present invention, the difference between the coefficient of linear expansion of the cured product forming the optical waveguide and the coefficient of linear expansion of each component shows good heat cycle resistance at a specific value or less. Suggests that the strain due to thermal expansion inside the optical waveguide is related to the optical characteristics, the present invention focuses on the specific linear expansion coefficient, and the difference in linear expansion coefficient, various optical waveguides The invention was completed based on the findings found as a result of the formation. Assuming that the refractive index of each of these layers is n1 (lower cladding layer), n2 (core portion), and n3 (upper cladding layer), respectively, from the optical requirement of the optical waveguide, n2> (N1 or n3). By doing so, the optical signal can be efficiently guided into the optical waveguide.

The type of the base material used in the optical waveguide of the present invention has a linear expansion coefficient in the range of -20.degree.
It is selected from materials having a ppm / K or less, preferably 50 ppm or less. Examples of such materials include silicon, metals such as titanium, silicon carbide, boron carbide, metal carbides such as titanium carbide, silicon nitride,
At least two kinds of metal nitrides such as boron nitride, oxides of one kind of metal such as alumina, fused quartz, zirconia, mullite, cordulite, soda-lime glass, borosilicate glass, Pyrex (registered trademark), etc. Inorganic substrates such as glass containing metals, polyimides, polyarylates, melamine resins, epoxy resins, crosslinked polyacrylates, crosslinked polymethacrylates, polyolefins, etc., having a glass transition temperature of 200 ° C or higher, thermoplastic or crosslinked You can choose from organic polymers. These substrates may be used alone or in a multilayer structure.

[0008] Among these, preferred substrates are as follows:
Examples of the inorganic substrate include silicon, fused quartz, alumina, pyrex, and borosilicate glass, and examples of the organic substrate include a thermoplastic or crosslinked organic polymer having a glass transition temperature of 200 ° C. or higher, such as polyimide, epoxy resin, and polyolefin. Can be.

An advantage of using a curable material for forming an optical waveguide is that the formed optical waveguide has high thermal and chemical durability, for example, and a thermoplastic resin is used as easily imagined. In this case, the reliability is low because the optical waveguide is easily deformed in a high temperature environment. In addition, it has a disadvantage of low durability against chemicals such as organic solvents. Examples of the curing mode used for forming the optical waveguide of the present invention include thermal curing and light curing. Since the thermosetting has a feature that the process is simple, it can be used for forming the lower or upper clad layer. On the other hand, light curing is preferred for forming the core portion because of the advantage that patterning is easy. Since photocuring can be achieved at low temperature and in a short time, it is also possible to use photocuring to form the lower or upper cladding layer. Reliability is a problem when using a thermoplastic resin by using a curable material in any form,
It has the feature that durability against chemicals is improved.

The silica compound forming the optical waveguide of the present invention is at least one compound selected from the group consisting of a hydrolyzable silane compound represented by the following general formula (1), a hydrolyzate thereof and a condensate thereof. (Hereinafter referred to as "siloxane (A)" or "component (A)"). RmSi (X) _4-m (1) (R is a non-hydrolyzable organic group having 1 to 12 carbon atoms, X is a hydrolyzable group, and m is 0 to 3) In the general formula (1), R is ¹ is a non-hydrolyzable cyclic, branched or straight-chain alkyl group having 1 to 12 carbon atoms, an aryl group, or an aralkyl group, and some or all of the hydrogen atoms on the substituent are deuterium; May be substituted with fluorine or chlorine, m
Is 0-3. One of these hydrolyzable silane compounds
Selected from more than species.

Specifically, examples of the alkyl group include methyl, ethyl, propyl, butyl, octyl, dodecyl,
And their deuterium substitutes, phenyl, biphenyl and naphthyl as aryl groups, and deuterium, fluorine, chloride and aralkyl groups thereof as tolyl, xylyl,
Mesityl, and deuterium, fluorine and chloride thereof. Preferred alkyl groups are methyl group, 3,3,3-
Trifluoropropyl and trideuteriomethyl, preferred aryl groups include phenyl, pentafluorophenyl and pentadeuteriophenyl, and preferred aralkyl groups include trifluoromethylphenyl and bis (trifluoromethyl) phenyl.

Examples of the hydrolyzable group X include a hydrogen atom, an alkoxy group having 1 to 12 carbon atoms, a halogen atom, an amino group, and an alkyl carboxylate group. The alkoxy group includes an alkoxy group corresponding to the alkyl group represented by R, and a halogen atom is fluorine, chlorine, an amino group is amino, dimethylamino, diethylamino, an alkylcarboxylate is acetoxy, propiolate, and a preferable X is an alkoxy group. And more preferably methoxy and ethoxy.

Specific examples of the silane compound represented by the general formula (1) include tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetra (2-methacryloxyethoxy) silane, and tetra (2-acryloxyethoxy). ) Silane, tetrachlorosilane, tetraacetoxysilane, tetraaminosilane, methyltrimethoxysilane, methyltrichlorosilane, methyldichlorosilane,
Methyldimethoxysilane, methyltriacetoxysilane, trideuteriomethyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane,
3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane, benzyltrimethoxysilane, phenyltrimethoxysilane, phenylsilane, phenyltriacetoxysilane, phenyltriaminosilane, phenyltrimethoxysilane Chlorosilane, phenyltriethoxysilane, pentafluorophenyltrimethoxysilane, pentafluorophenyltrichlorosilane, pentadeuteriophenyltrimethoxysilane, pentadeuteriophenyltriacetoxysilane, pentadeuteriophenyltrichlorosilane, pentadeuteriophenyltriethoxysilane Silane, xylyltrimethoxysilane, trifluoromethylphenyltothimethoxysilane, biphenyltrimethoxysilane, biphenyl Trichlorosilane, bis (tri Zhu Theriault methyl) dimethoxysilane, dimethyl dimethoxysilane, dimethyl dichlorosilane, diphenyl dimethoxysilane, diphenyl dichlorosilane, trimethylchlorosilane, mention may be made of trimethyl methoxy silane, triethylsilane, triethylchlorosilane the like. Preferred specific examples include tetramethoxysilane, tetraethoxysilane, tetraacetoxysilane,
Examples include methyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, phenyltrimethoxysilane, and dimethyldimethoxysilane.

When the hydrolyzable group is an alkoxy group, the conditions for hydrolyzing or condensing the hydrolyzable silane compound used as a raw material for producing siloxane can be carried out without adding a solvent in the hydrolysis and condensation steps. can do.

On the other hand, when the hydrolyzable group is a raw material that does not produce by-products serving as diluting solvents such as halogen groups and produces an acid serving as an autocatalyst, an organic solvent described later is added in advance. It is desirable to carry out hydrolysis and condensation reactions after dilution. In that case, the generated acid remains after the reaction,
From the viewpoint of impairing the stability of the curable composition, for example, it is preferable to obtain a stable curable composition by adding steps such as neutralization with a basic substance, washing with water, and addition of an ion exchange resin. . The hydrolysis and condensation steps of a silane compound when the hydrolyzable group is an alkoxy group will be described below as an example. That is, it is performed by the following steps 1) to 4).

1) A hydrolyzable silane compound is contained in a container. 2) Next, a predetermined amount of water and a catalyst are added dropwise with stirring. This step is a step of initiating hydrolysis of the hydrolyzable silane, and is performed at the same temperature as in step 1) under a dry atmosphere. When the amount of water to be added is P mol and the number of mols of the total hydrolyzable groups in the hydrolyzable silane compound is Q, P / Q
If the ratio is too small, the yield and molecular weight of the hydrolysis and condensate decrease, resulting in a decrease in the durability of the formed optical waveguide.
On the other hand, when the P / Q ratio is too large, the storage stability is reduced because the molecular weight exceeds the appropriate range. For this reason, the reaction is usually performed in the range of 0.1 <P / Q <7, preferably in the range of 0.3 <P / Q <4. As the water to be added, ion-exchanged water and distilled water are usually used. Further, a catalyst may be added for the purpose of accelerating the reaction, and the amount of the catalyst added is 0.0001 to 10 parts by weight, preferably 0.001 to 1 part by weight, per 100 parts by weight of the hydrolyzable silane.
Parts by weight. The method of adding the catalyst is not particularly limited, but it is preferably added as an aqueous solution. Catalysts include formic acid, acetic acid, oxalic acid, lactic acid, malonic acid, citric acid, tartaric acid, malic acid, succinic acid, fumaric acid, phthalic acid, pyromellitic acid,
Monovalent, divalent, trivalent organic acids such as p-toluenesulfonic acid, methanesulfonic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, hydrochloric acid, phosphoric acid, nitric acid, hydrofluoric acid, bromic acid, chloric acid, Inorganic acids such as chloric acid, alkali metals and alkaline earth hydroxides and quaternary alkyl ammonium hydroxides and carbonates in the periodic table, alkalis such as primary to tertiary amines, ammonium chloride, tetramethyl Ammonium chloride, tetrabutylammonium bromide, acidic salts such as tetrabutylammonium sulfonate, sodium hypochlorite, basic salts,
Metal alkoxides other than silicon such as tin, zirconium, titanium, aluminum and boron, and their chelate complexes, and the like. Among them, organic catalysts such as organic acids, inorganic acids, metal alkoxides, chelate compounds of metal alkoxides and the like can be mentioned. Preferably, organic acids are particularly preferred.

3) Then, the mixture is heated and stirred at a predetermined temperature for a predetermined time. This step is a step of performing hydrolysis and condensation of the hydrolyzable silane, and the reaction temperature is performed at a temperature equal to or lower than the boiling point of the silane compound, water, and the alcohol by-produced by the hydrolysis, and is usually 0 ° C to 150 ° C, preferably. Is performed in a dry atmosphere at 20 ° C to 100 ° C. The reaction time is usually 1 hour to 12 hours. 4) Dilute by adding a predetermined solvent. In this step, dilution or replacement with a predetermined solvent is performed, but replacement with a diluting solvent suitable for forming an optical waveguide is preferably performed at this stage. Preferred diluting solvents include ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, cyclohexanone, acetylacetone, and diacetone alcohol; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol diethyl ether; and carbonization such as toluene and xylene. Hydrogen, methanol, ethanol, butanol, octanol, alcohols such as furfuryl alcohol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylene glycol monoethyl ether,
One or two ether-based alcohol solvents such as diethylene glycol monoethyl ether, propylene glycol monomethyl ether and propylene glycol monoethyl ether, and ester solvents such as ethyl acetate, butyl acetate, amyl acetate, octyl acetate, ethyl lactate and butyl lactate. Selected in combination of more than one species. Preferred solvents are ketone, alcohol, ether-containing alcohol and ester solvents, more preferably methyl isobutyl ketone, cyclohexanone, diacetone alcohol, butyl alcohol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethyl lactate. Butyl lactate.

These diluting solvents are used in an amount of 10 to 1000 parts by weight, preferably 40 to 250 parts by weight, based on 100 parts by weight of the component (A). The method of solvent replacement is not particularly limited, and examples thereof include a method of performing distillation replacement under normal pressure and a method of performing distillation under reduced pressure.

The molecular weight of the siloxane is preferably in the range of 500 to 50,000, and more preferably 1,000 to 10,000 in terms of polystyrene equivalent weight average molecular weight determined by gel permeation chromatography (hereinafter abbreviated as GPC). If the weight average molecular weight is less than 500, the durability of the optical waveguide is reduced,
On the other hand, if it exceeds 50,000, the storage stability decreases, which is not preferable.

When a cured product of the siloxane (A) for forming the optical waveguide is formed, the cured product can be formed by heat or light irradiation, and at this time, a curing catalyst may be added. To such a curing catalyst, either a compound that promotes curing by heating, a compound that promotes curing by light irradiation, or both can be added.

Specific examples of compounds which accelerate curing by heating as curing catalysts include, for example, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, oxalic acid, acetic acid, malonic acid, succinic acid, phthalic acid, and the like. Organic acids such as methanesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, ammonia, triethylamine, tributylamine, trioctylamine, pyridine, quinoline, amines such as diazabicycloundecane, sodium hydroxide, potassium hydroxide, Alkali metal hydroxides such as lithium hydroxide and cesium hydroxide, sodium acetate, sodium oxalate, sodium methanesulfonate,
Sodium paratoluenesulfonate, salts of organic acids and basic substances such as ammonium paratoluenesulfonate, quaternary ammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, Metal alkoxides such as tetrabutoxy tin, tetraisopropoxy titanium, tetrabutoxy titanium, tetrabutoxy zirconium, diisopropoxy zinc, tributoxy aluminum, and chelate compounds such as these metal alkoxides and acetylacetone, ethyl acetoacetate, ethylenediamine and the like. And organic metal compounds such as dibutyltin dilaurate and butyltin triisopropoxide.

These curing catalysts can be used by adding 0.001 to 10 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight of the siloxane (A). Compounds that promote curing by light irradiation as curing catalysts include compounds that generate active radical species by photolysis, compounds that generate basic substances by photolysis, and compounds that generate acidic substances by photolysis. Can be. Among these, a compound that generates an acidic substance by photolysis is more preferably used as a curing catalyst for forming a cured product having good optical properties.

Compounds that generate active radical species by photolysis are compounds known in the chemical industry as photoradical initiators. Specific examples of the photoradical initiator include, for example, acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1.
-One, carbazole, xanthone, 4-chlorobenzophenone, 4,4'-diaminobenzophenone, 1,1
-Dimethoxydeoxybenzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthones, 2-methyl-1- [4- (methylthio) phenyl]
-2-morpholino-propan-2-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, triphenylamine, 2,
4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl)-
2,4,4-tri-methylpentylphosphine oxide, benzyldimethylketal, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone,
Fluorene, benzaldehyde, benzoin ethyl ether, benzoin propyl ether, benzophenone,
Michler's ketone, 3-methylacetophenone, 3,
Examples include 3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone (BTTB) and a combination of BTTB with xanthene, thioxanthene, coumarin, ketocoumarin and other dye sensitizers. Of these, benzyldimethyl ketal, 1
-Hydroxycyclohexyl phenyl ketone, 2,4
6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethylamino-1- (4-
Morpholinophenyl) -butan-1-one and the like are particularly preferred.

The above-mentioned photo-radical initiators can be used alone or in combination of two or more kinds. %, Preferably 0.1 to 8% by weight. Compounds that generate a basic substance by photolysis are known as photobase generators in the chemical industry, and specific examples include, for example, benzylcarbamate compounds, benzoincarbamate compounds, O-carbamoylhydroxyamines, O- Carbamoyl oxime, aromatic sulfonamides, N- (2-allylethenyl) amides,
Aryl azides, N-arylformamides, and N-
Substituted-4- (orthonitrophenyl) dihydropyridines can be mentioned. Specific examples include 4- (orthonitrophenyl) dihydropyridine, orthonitrobenzylcarbamate, 1,2,3,4-tetrahydronaphthalene-1-ylidene, and the like.

The amount of the compound capable of generating a basic substance by photolysis is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the siloxane (A).
More preferably, it is 0.1 to 1 part. If the amount is less than 0.01 part by weight, the photocurability becomes insufficient, and if the amount exceeds 10 parts by weight, the optical characteristics as an optical waveguide deteriorate. Compounds that generate acidic substances by photolysis are known in the chemical industry as photoacid generators. As the type of the photoacid generator as the component (B), an onium salt having a structure represented by the general formula (2) (a first group of compounds) or a structure represented by the general formula (3) Sulfonic acid derivatives (the second group of compounds) can be mentioned. Particularly effective compounds are the aromatic onium salts.

For example, Japanese Patent Application Laid-Open No. 50-151996,
Aromatic halonium salts described in JP-A-50-158680, JP-A-50-151997, JP-A-52-30899, JP-A-56-55420, JP-A-55-125105 VI described in Japanese Patent Publication
Group A aromatic onium salts, VA group aromatic onium salts described in JP-A-50-158699 and the like;
No. 8428, JP-A-56-149402, oxosulfoxonium salts described in JP-A-57-192429, aromatic diazonium salts described in JP-A-49-17040, U.S. Pat. Fourth, 139,
Thiolylium salts described in JP-A-655-655 are preferred. Further, an iron / allene complex, an aluminum complex / photolytic silicon compound-based initiator and the like can also be mentioned. During ^{_{[R 4 a R 5 b R}} 6 c R 7 dW] + m [MZ m + n] ^over m (2) [Formula (2), cation is an onium ion,
W is S, Se, Te, P, As, Sb, Bi, O, I, Br, Cl or a ^{-N≡N,, R 4, R 5} , R 6, R 7 are the same or different organic groups A, b, c, and d are each an integer of 0 to 3, and (a + b + c + d) is equal to the valence of W. Also, M
Is a metal or metalloid constituting the central atom of the halide complex [MZ _{m + n} ], for example, B, P, As, Sb,
Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn, Co
It is. Z is, for example, a halogen atom or an aryl group such as F, Cl, or Br, m is the net charge of the halide complex ion, and n is the valence of M.] Q _S — [S (SO) ₂ -R ⁸ ] _t (3) [In the general formula (3), Q represents a monovalent or divalent organic group, R ⁸
Is a monovalent organic group having 1 to 12 carbon atoms, the suffix s is 0 or 1, and the suffix t is 1 or 2. First, the onium salt which is the first group of compounds is acid-activated by receiving light. A compound that can release a substance. Specific examples of [MZ m + _n] in the general formula (2) where, tetrafluoroborate (BF ₄ ^over), hexafluorophosphate (PF ₆ ^{chromatography),} hexafluoroantimonate (Sb ₆ ^{chromatography),} hexafluoro Arsenate (AsF ₆
^{Chromatography),} among such onium salts, (B) component and then hexachloroantimonate (SbCl ₆ ^{chromatography),} tetraphenylborate (BPh ₄ ^over), tetrakis (trifluoromethylphenyl) borate [B (CF3-Ph) ₄ ^{chromatography,} and the like pentakis (pentafluorophenyl) borate (B (C6 F5) ₄ ^over).

The anion used in the general formula (2)
[MZ_{m + n}] Instead of the general formula (MZ_nOH ^ー)
Anions can also be used. In addition,
ON (ClO _Four-), Trifluoromethanesulfonate ion
(CF_ThreeSO_Three ^ー), Fluorosulfonic acid (FSO)_Three ^ー), Torr
Ensulfonate ion, trinitrobenzene sulfo
Acid ion, trinitrotoluenesulfonic acid ion,
Use of onium salts with other anions such as
You can also.

Next, the second group of compounds will be described.
Examples of the sulfonic acid derivative represented by the general formula (3) include disulfonic acids, disulfonyldiazomethanes, disulfonylmethanes, sulfonylbenzoylmethanes, imidosulfonates, benzoin sulfonates, 1- Oxy-2-hydroxy-3-propyl alcohol, sulfonates, pyrogallol trisulfonates, and benzyl sulfonates. Further, among the sulfonic acid derivatives represented by the general formula (3), imide sulfonates are more preferable, and trifluoromethane sulfonate derivatives are more preferable.

Commercially available compounds which can be suitably used as a photoacid generator include UVI-6950 and UVI-697.
0, UVI-6974, UVI-6990 (all manufactured by Union Carbide), Adeka Optomer SP-15
0, SP-151, SP-170, SP-171, SP
-172 (manufactured by Asahi Denka Kogyo KK), Irgaccu
re 261 (all manufactured by Ciba Specialty Chemicals Co., Ltd.), CI-2481, CI-2624, C
I-2639, CI-2064 (Nippon Soda Co., Ltd.
Manufactured), CD-1010, CD-1011, CD-101
2, KI85 (all manufactured by Sartomer), DS-10
0, DS-101, DAM-101, DAM-10
2. DAM-105, DAM-201, DSM-30
1, DTS-103, NAI-100, NAI-10
1, NAI-105, NAI-106, PAI-101,
SI-100, SI-101, SI-105, SI-1
06, PI-105, NDI-105, BENZOIN TOSYLAT
E, MBZ-101, MBZ-301, PYR-10
0, PYR-200, DNB-101, NB-101, N
B-201, NDS-103, NAT-103, NAT-
105, NDS-103, NDS-105, NDS-
155, NDS-165, CMS-105, TPS-
102, TPS-103, TPS-105, MDS-1
03, MDS-105, MDS-205, MDS-30
5, DTS-103, MPI-103, BBI-10
1, BBI-102, BBI-103, BBI-105,
BBI-106, BBI-109, BBI-201, D
PI-105, DPI-109, DPI-201, MPI
-103, MPI-105, MPI-106, MPI-
109 (all manufactured by Midori Kagaku Co., Ltd.), PCI-061
T, PCI-062T, PCI-020T, PCI-0
22T (all manufactured by Nippon Kayaku Co., Ltd.), IBPF and IBCF (all manufactured by Sanwa Chemical Co., Ltd.). Of these, more preferred photoacid generators include those having a wavelength of 20
An onium salt photoacid generator, which is a first group of compounds having an absorption maximum of 0 nm or more at 360 nm or less, may be mentioned.

The amount of the photoacid generator is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of the siloxane (A). If the amount is less than 0.01 part by weight, the photocurability becomes insufficient, and 10
If the amount exceeds the weight part, the optical characteristics of the optical waveguide will deteriorate.

In the present invention, when a pattern is formed by photo-curing using siloxane (A) as a photo-acid generator as a curing catalyst, diffusion of an acidic active substance generated from the photo-acid generator into the coating is controlled. An acid diffusion controller (hereinafter, also referred to as “component (C)”) may be added for the purpose of suppressing the curing reaction in the non-irradiated region. However, in order to distinguish it from the photoacid generator by definition, the acid diffusion controller of the component (C) is a compound having no acid generating function. By adding such an acid diffusion controlling agent, the photocurable composition can be effectively cured, and the pattern accuracy can be improved.

In the present invention, the acid diffusion controller is preferably a nitrogen-containing organic compound whose basicity is not changed by exposure or heat treatment during the formation step. Examples of such a nitrogen-containing organic compound include a compound represented by the following general formula (4) (hereinafter, referred to as “nitrogen-containing compound (I)”). NR ⁹ R ¹⁰ R ¹¹ (4) [In the general formula (4), R 9, R 10 and R 11 are independent of each other and are a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or Represents a substituted or unsubstituted aralkyl group. Examples of another nitrogen-containing organic compound include a diamino compound having two nitrogen atoms in the same molecule (hereinafter, referred to as “nitrogen-containing compound (II)”) and a diamino polymer having three or more nitrogen atoms. (Hereinafter, referred to as "nitrogen-containing compound (III)"), or an amide group-containing compound, a urea compound, a nitrogen-containing heterocyclic compound, and the like. Here, as the nitrogen-containing compound (I), monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; di-n-butylamine, di-n -Pentylamine,
Di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n
Dialkylamines such as -decylamine; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine , Tri-n-nonylamine, trialkylamines such as tri-n-decylamine; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline,
Aromatic amines such as 4-nitroaniline, diphenylamine, triphenylamine, and 1-naphthylamine; and alkanolamines such as ethanolamine, diethanolamine, and triethanolamine. Examples of the nitrogen-containing compound (II) include, for example, ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, N, N, N ′, N′-tetrakis (2) -Hydroxyethyl) ethylenediamine, N, N, N ',
N'-tetrakis (2-hydroxypropyl) ethylenediamine, 4,4'-diaminodiphenylmethane, 4,
4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2'-bis (4-aminophenyl) propane,
2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3
-Hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) propane,
Examples thereof include 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene and 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene. Examples of the nitrogen-containing compound (III) include, for example, polymers of polyethyleneimine, polyallylamine, and dimethylaminoethylacrylamide.

Examples of the amide group-containing compound include, for example, formamide, N-methylformamide, N, N-
Examples thereof include dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone. Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tributylthiourea. Can be mentioned. Examples of the nitrogen-containing heterocyclic compound include imidazoles such as imidazole, benzimidazole, 2-methylimidazole, 4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, and 4-methyl-2-phenylimidazole; Pyridine, 2-methylpyridine,
4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N-methyl-4-phenylpyridine, nicotine, nicotinic acid, nicotinamide, quinoline, 8-oxyquinoline, Pyridines such as acridine; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine,
Examples thereof include piperidine, morpholine, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, and 1,4-diazabicyclo [2.2.2] octane.

Of these nitrogen-containing organic compounds, nitrogen-containing compounds (I) and nitrogen-containing heterocyclic compounds are preferred. Further, among the nitrogen-containing compounds (I), trialkylamines are particularly preferable, and among the nitrogen-containing heterocyclic compounds, pyridines are particularly preferable. The acid diffusion controller can be used alone or as a mixture of two or more. The amount of the acid diffusion controller is preferably in the range of 0.001 to 15 parts by weight based on 100 parts by weight of the siloxane as the component (A). The reason is that if the amount of the acid diffusion controller is less than 0.001 part by weight, depending on the process conditions,
This is because the pattern shape and dimensional reproducibility of the optical waveguide may decrease. On the other hand, if the amount of the acid diffusion controller exceeds 15 parts by weight, the photocurability of the component (A) may decrease. Because there is. Therefore, it is more preferable that the amount of the acid diffusion controller added is in the range of 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, based on 100 parts by weight of the siloxane as the component (A). It is more preferable to set the value within the range.

In the present invention, a surface tension reducing agent (D) (hereinafter sometimes referred to as “component (D)”) may be further added to the siloxane (A). The component (D), a surface tension reducing agent, improves the coating performance resulting from surface tension incompatibility, such as repelling, unevenness, and undulation of the coating film in the step of coating the curable composition when forming the cured product of the present invention. Selected from compounds having the function of reducing the surface tension with a small amount of addition. Such surface tension reducing agents can be selected from commercially available surfactants, leveling agents, defoamers, defoamers, foam stabilizers, and paint additives. The surface tension reducing agent is basically a compound containing both a polar group and a hydrophobic group. Structurally, silicone-based, organic-based, and fluorine-based products are commercially available, and these are classified into anionic, nonionic, cationic, and amphoteric, respectively, depending on the ionicity of the polar group. The surface tension reducing agent can be selected from the compounds described above.Since the compatibility with aminopolysiloxane, which is a main constituent of the present invention, is high and the effect can be obtained in a very small amount, the silicone-based or surface-lowering agent can be used. Fluorine surface tension reducing agents are preferred. The silicone-based surface tension reducing agent is selected from polyether-modified silicones, polyester silicones, alkyl-modified silicones, acrylic silicones, and the like. A surface tension reducing agent is selected. In addition, the fluorine type is selected from fluoroalkyl silicones, fluoroalkyl carboxylic acids, fluoroalkyl alcohols, fluoroalkyl ethers, and fluoroalkyl quaternary ammonium salts. These may be used alone or in combination of two or more.

The amount of the surface tension reducing agent to be added is 0.1 to 0.0001 parts, preferably 100 parts by weight of the siloxane (A).
0.1 to 0.001 part. Also, the solid content after drying in the composition
For 100 parts by weight, 1 to 0.001 part, preferably 1 to 0.01
Department. When the addition amount of the surface tension reducing agent is less than 0.0001, the homogeneity and the smoothness of the optical waveguide of the present invention may be reduced. On the other hand, when it exceeds 0.1, the durability of the optical waveguide is reduced. The surface tension reducing agent may be added at any stage during the production of the composition for forming the cured product of the present invention, but (A)
It is preferably added after the production of the component polysiloxane. The method of addition is not limited as long as the surface tension reducing agent is uniformly dissolved in the composition. However, the method of adding the compound after dilution with an organic solvent in advance is preferable because the time until uniformization can be shortened. As an example of a commercially available product, a silicone-based product manufactured by Dow Corning Toray Silicone Co., Ltd.
0, DC3PA, SH7PA, DC11PA, SH21PA, SH28PA, SH29PA, S
H30PA, ST80PA, ST83PA, ST86PA, ST90PA, ST94PA, ST9
6PA, ST97PA, ST101PA, ST102PA, ST103PA, ST105PA, S
T110PA, SH550, SH710, etc., as well as SH200, FS1265, SH203, SD559 which have been commercialized as silicone defoamers
1, SH7PA, commercialized as silicone for cosmetics
SH3746, SH3771C, SH3772C, SH3773C, SH3775C, SH374
8, SH3749, and the like. In addition, BYK-300, BYK-301, BYK-335, and BYK-3, which are commercialized as silicone-based surface conditioners manufactured by BYK Japan KK
02, BYK-331, BYK-306, BYK-330, BYK-341, BYK-344, B
YK-307, BYK-332, BYK-333, BYK-310, BYK-077, BYK-315, which have been commercialized as silicone-based leveling agents
BYK-370, BYK-325, BYK-322, BYK-323, etc.BYK-370, B commercialized as reactive silicone surface conditioners
BYK-UV3500, BYK-UV3510, which have been commercialized as UV curable surface conditioners such as YK-371, BYK-373, and BYK-375
BYK-UV3530, and BYK-051 and BYK-0, which are commercialized as non-silicone defoamers for solvent-based and solvent-free paints
52, BYK-053, BYK-055, BYK-057, and the like. An example of a product that has been commercialized as a fluorine-based paint additive is Floren manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.
AC-300, Floren AC-900, Floren AO-3, Floren AKS, Flonon SB-110N, Flonon SB-210, Flonon SB-510, Flonon SB-551, EF-3 manufactured by Shin-Akita Chemical Co., Ltd.
05, EF-306A, etc.

Examples of surfactants that have been commercialized include, for example, Emal 0 and Emal AD-25R manufactured by Kao Corporation,
Emar TD, Emar E-27C, Emar NC-35, Rheodor MS-50, Rheodor SP-L10, Rheodor AO-10, Rheodor TW-L120, Rheodor TW-O120, Rheodor super
TW-S120, Leodor 430, Neoperex F-25, Neoperex No25, Emanon 1112, Emanon 4110EMANO-
NN3299, Emazol L-10H, Emazol P-120, Emazol O-120, etc., manufactured by Kao Atlas Co., Ltd., Emulgen 105, Emulgen 108, Emulgen 147, Emulgen 210, Emulgen 320P, Emulgen 404, Emulgen 430, Emulgen
903, Emulgen 906, Emulgen 920, Emulgen 950,
Emulgen 705, Emulgen PP-150, Emulgen PP-23
0, Emulgen PP-250, Emulgen PP-290, Amit 10
5, Amyt 308, Amyt 320, Cotamine 24P, Cotamine D-86P, Amphitol 24B, Amphitol 86B and the like. Among these surfactants, nonionic surfactants are particularly preferable.

In addition, it can be further added to the siloxane (A) containing the following components as long as the effects of the present invention are not impaired. The photosensitizer is selected from condensed aromatic compounds having an absorption at a wavelength of 300 nm or more for the purpose of increasing the sensitivity to light when forming a cured product containing a polysiloxane by photocuring in the present invention and increasing the efficiency of the curing. Is added. The condensed aromatic compound used as the photosensitizer may have a hetero atom, for example, oxygen, sulfur, nitrogen, phosphorus, halogen (fluorine, chlorine, bromine, iodine) and the like.

Absorbance at a wavelength of 300 nm or more has an optical path length of 1 cm.
The concentration can be defined by the molar extinction coefficient measured in mol / liter, the molar extinction coefficient of the condensed aromatic compound is preferably 1000 or more, more preferably 10,000 or more to further improve the radiation curability of the composition be able to. The addition amount of the condensed aromatic compound is 0.0001 to 1 part by weight, preferably 100 parts by weight of the siloxane of the component (A),
0.001 to 0.1 part. Specific examples of the condensed aromatic compound having an absorption at a wavelength of 300 nm or more include anthracene, cyanoanthracene, bromoanthracene, chloranthracene, 2-ethyl-9,10-dimethoxyanthracene, 9
Anthracene derivatives such as -hydroxymethylanthracene, anthraquinone, 2-hydroxymethylanthiquinone, ethylanthraquinone, anthraquinone derivatives, thioxanthone, chlorothioxanthone, diethylthioxanthone, isopropylthioxanthone, 3-
(Diethylthioxanthonyloxy) -2-hydroxyxitrimethylammonium, thioxanthone derivatives such as thioxanthone, benzophenone, methyl orthobenzoylbenzoate, [4- (methylphenylthio) phenyl] phenylmethane, 4,4′-bisdiethylaminobenzophenone Benzophenone derivatives such as, 4-benzoylbiphenyl and 1,4-dibenzoylbenzene; naphthalene derivatives such as benzyl, naphthalene and benzoylnaphthalene; 10-butyl-2-chloroacridone;
Acridone derivatives such as acridone, perylene derivatives,
6-methylcoumarin, diethylamino-4-methylcoumarin, 7-hydroxy-4-methylcoumarin, coumarin,
Coumarin derivatives such as dimethylaminobenzoate, isoamyl dimethylaminobenzoate and the like, aminobenzoic acid ester derivatives such as acridine, 1,7-diacridylheptane, acridine derivatives such as 9-hydroxy-4-methyxiacridine, N -Octyl-luvis (α-
And carbazole derivatives such as morphonyldimethylacetyl) carbazole, ethylcarbazole, and methylcarbazole. Among these, preferred compounds are anthracene, thioxanthone derivatives and benzophenone derivatives.

The crosslinking compound is selected from crosslinking compounds other than the crosslinking organic compound component (A), and examples of such crosslinking compounds include the following. As a first example, when a hydrolyzable silane compound or a condensate thereof that is polymerized with an acidic active substance other than (A) and cross-linked is exemplified, for example, glycidyloxypropyltrimethoxy is commercially available as a silane coupling agent. Epoxy-substituted alkoxysilanes such as silane, glycidyloxypropyltriethoxysilane, glycidyloxypropylmethyldimethoxysilane, glycidyloxypropyldimethylmethoxysilane, 2-trimethoxysilylethylcyclohexene oxide, and 2-triethoxysilylethylcyclohexene oxide Acryl-substituted alkoxysilanes such as methacryloxypropyltrimethoxysilane and acryloxytrimethoxysilane, mercaptopropyltrimethoxysilane and mercaptopropylmethyldimethoxysilane Examples include amino-substituted alkoxysilanes such as capto-substituted alkoxysilanes, aminopropyltriethoxysilane, and N-aminoethylaminopropyltrimethoxysilane, and one or more compounds selected from the group consisting of hydrolysis and condensation products thereof. be able to. As a second example, epoxy compounds containing one or more epoxy groups in the molecule, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, bromine Bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy novolak resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl -3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,
5-spiro-3,4-epoxy) cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, bis (3,4
-Epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-
3 ′, 4′-epoxy-6′-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadienediepoxide,
Di (3,4-epoxycyclohexylmethyl) ether of ethylene glycol, ethylenebis (3,4-epoxycyclohexanecarboxylate), dioctyl epoxyhexahydrophthalate, di-2-ethylhexyl epoxyhexahydrophthalate, 1,4- Butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether,
Polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers; polyglycidyl of polyether polyol obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin Ethers; diglycidyl esters of aliphatic long-chain dibasic acids; monoglycidyl ethers of aliphatic higher alcohols; monoglycidyl ethers of phenol, cresol, butylphenol or polyether alcohols obtained by adding alkylene oxide thereto; Glycidyl esters of higher fatty acids; epoxidized soybean oil; butyl epoxystearate; octyl epoxystearate; epoxidized linseed oil; It can be exemplified butadiene.

As a third example, examples of oxetane compounds containing one or more oxentane groups in the molecule include, for example, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane, 3-ethyl-3-phenoxy Oxetanes such as methyloxetane and bis (3-ethyl-3-methyloxy) butane can be mentioned. As a fourth example, examples of the vinyl ether compound containing one or more vinyl ether groups in a molecule include vinyl ethers such as ethylene glycol divinyl ether, triethylene glycol divinyl ether, and trimethylolpropane trivinyl ether. As a fifth example, a vinyl polymer containing one or more groups selected from the group consisting of one or more epoxy, oxetane, vinyl ether group and hydrolyzable silyl group in the molecule can be mentioned. These groups may be contained in the molecule in an amount of 0.1 to 50% by weight, preferably 1 to 30% by weight. The copolymerization of these functional groups can be carried out by radically copolymerizing (meth) acrylic esters containing these functional groups with a vinyl monomer as a main constituent, or by vinylic acid containing a carboxylic acid, epoxy group or hydroxy group. It is produced by a method of being introduced into a system polymer by a polymer reaction.

For example, in the production of a hydrolyzable silyl group-containing vinyl polymer, a carboxylic acid-containing vinyl polymer and glycidyloxypropyl trimethoxy are added to the method of radically copolymerizing methacryloxypropyltrimethoxysilane. It is produced by a method of reacting a silane, a method of reacting a hydroxy-containing vinyl polymer with trimethoxysilylpropyl isocyanate, a method of reacting an epoxy group-containing vinyl polymer with aminopropyltriethoxysilane, and the like. The weight average molecular weight by GPC of the vinyl polymer containing these crosslinkable groups is 500 to 100,000,
Preferably, 1000 to 50,000, more preferably 3000 to 100
00. Examples of the vinyl monomer serving as a main component of the vinyl polymer include styrene, α-methylstyrene, and other aromatic unsaturated ethylene-containing compounds, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, Alkyl (meth) acrylates such as phenyl (meth) acrylate, methyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, butyl (meth) acrylate, biphenyl (meth) acrylate, and hydroxyethyl (meth) acrylate , Hydroxypropyl (meth)
Acrylates, hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylate, acrylic acid, (meth) acrylic acids such as methacrylic acid,
N-vinylpyrrolidone, N-vinylcaprolactam, etc.
Examples thereof include unsaturated amides such as N-vinyllactams, (meth) acryloylmorpholine, and N, N-dimethyl (meth) acrylamide. The production of the vinyl polymer is carried out by a known method in which a mixed solution of a diazo-based thermal radical polymerization initiator such as bisazovaleronitrile, a vinyl monomer, and an organic solvent is heated and stirred for 1 to 10 hours in a range of 50 ° C to 150 ° C. Manufactured. The addition of the crosslinkable organic compound is usually performed by a method of mixing with the component (A). When the siloxane of the component (A) is produced, a mixture of the hydrolyzable silane and the crosslinkable organic compound is hydrolyzed and blended. It is also possible.

Inorganic Fine Particles For the purpose of increasing the strength of the optical waveguide of the present invention, inorganic fine particles can be added. The element constituting the inorganic fine particles is not particularly limited, but is preferably an oxide or a nitride. Examples of the oxide include silicon oxide, aluminum oxide, boron oxide, titanium oxide, zirconium oxide, zinc oxide, cerium oxide, and nitride. Examples of the material include silicon nitride and boron nitride. The average particle diameter of these inorganic fine particles is 1 to 100
A material having a particle diameter of less than 1 nm is not stably present, while a particle diameter of more than 100 nm deteriorates the smoothness of the optical waveguide, thereby deteriorating the optical characteristics. The amount of addition can be 1 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the aminopolysiloxane (A). If the amount is less than 1 part by weight, the effect of improving the strength is low, while if it exceeds 200 parts by weight, the strength is undesirably reduced. Although the inorganic fine particles are obtained as a powder or a solvent-dispersed colloidal liquid, a solvent-dispersed colloidal liquid is more preferable because of its good dispersibility in the composition. In addition, in order not to impair optical transmission loss due to light scattering in the optical waveguide,
The refractive index difference between the inorganic fine particles and the siloxane of the component (A) is 0.03.
Or less, more preferably 0.003 or less. Examples of colloidal silica among the examples of commercially available inorganic fine particles include Nissan Chemical Industries, Ltd.Snowtex O, Snowtex N, methanol silica sol,
Examples include IPA-ST, MEK-ST, NBA-ST, DMAC-ST, and the like.

Metal alkoxides can be added for the purpose of controlling the refractive index of the optical waveguide of the present invention. Illustrative of such metal alkoxides are Ge, Sn, B, Al, Ga, I
n, Sb, Ti, Zr, and the alkoxy group has 1 carbon atom
1 to 12 linear, branched or cyclic alkoxy groups. To show specific examples, tetramethoxygermanium,
Tetraethoxygermanium, tetrabutoxygermanium, methyltriethoxygermanium, phenyltrimethoxygermanium, tetrabutoxytin, tetrabutoxytin, methyltributoxytin, trimethoxyborane, triethoxyborane, tributoxyborane, tributoxyaluminum, tris (ethyl Acetoacetonato) aluminum, dibutoxy (acetylacetonato)
Aluminum, triisopropoxygallium, tributoxygallium, triisopropoxyindium, tributoxyindium, triisopropoxyantimony, tributoxyantimony, tetraisopropoxytitanium,
Tetrabutoxy titanium, diacetylacetonate (dibutoxy) titanium, tetrakis (ethyl acetoacetonate)
Titanium, tetraisopropoxyzirconium, tetrabutoxyzirconium, tetrakis (ethylacetoacetonato) zirconium and the like can be mentioned. The amount of the metal alkoxide to be added is 50 to 0.01 parts based on 100 parts by weight of the siloxane as the component (A), and is added after or before the production of the siloxane as the component (A). When it is added before the production, it is preferable that it is mixed with the hydrolyzable silane compound at the time of producing the siloxane and then hydrolyzed and co-condensed.

This is an embodiment when an optical waveguide is formed, and the production of an optical waveguide by photo-curing will be described as an example. 1. Preparation of a photocurable composition for forming an optical waveguide A lower clad layer constituting an optical waveguide, a composition for forming an optical waveguide for forming a core portion and an upper clad layer, that is, a lower layer composition, a core composition and The composition for the upper layer can be prepared by mixing and stirring the above-mentioned siloxane, curing catalyst and the like according to a conventional method. Further, as the prepared lower layer composition, core composition and upper layer composition, respectively, the relationship between the refractive indices of each part finally obtained, so as to satisfy the conditions required for the optical waveguide, It is preferable to use different photocurable compositions for forming an optical waveguide.

Accordingly, by appropriately selecting the type of the hydrolyzable silane compound, which is the raw material of the siloxane as the component (A), a photocurable composition for forming an optical waveguide, which can provide cured films having different refractive indices, can be obtained. can do. Then, using two or three kinds of light-curable compositions for forming an optical waveguide such that the difference in the refractive index becomes an appropriate size, the light-curable composition for forming an optical waveguide that gives a cured film having the highest refractive index is used. It is preferable to use another composition as the composition for the core and the composition for the lower layer and the composition for the upper layer.

However, the composition for the lower layer and the composition for the upper layer may be the same composition for forming an optical waveguide. Usually, the same composition is economically advantageous, This is more preferable because it also becomes easy. Further, when preparing each composition for forming an optical waveguide, its viscosity is set to 1 to 1
The value is preferably in the range of 000 cps (25 ° C.), more preferably in the range of 5 to 8,000 cps (25 ° C.), and more preferably 10 to 5,000 cps.
(25 ° C.) is more preferable.
The reason for this is that if the viscosity of each optical waveguide forming composition falls outside these ranges, it may be difficult to handle or to form a uniform coating film. In addition, the viscosity of the composition for forming an optical waveguide can be appropriately adjusted depending on the amount of the reactive diluent or the organic solvent.

2. An optical waveguide having a cross section of the structure shown in FIG. 1 is formed through the steps shown in FIG. That is, the lower cladding layer 1
3. The core portion 15 and the upper clad layer 17 (not shown) are formed by applying a composition for forming an optical waveguide for forming the layers and then thermally or light-curing the composition. Is preferred. In the following formation examples, the lower cladding layer, the core portion, and the upper cladding layer are each a composition for forming an optical waveguide, which is a composition for forming an optical waveguide from which a cured product having a different refractive index after curing is obtained. , And an upper layer composition.

Preparation of Substrate First, as shown in FIG. 2A, a substrate 12 having a flat surface is prepared. Although the type of the substrate 12 is not particularly limited, for example, a silicon substrate, a glass substrate, or the like can be used. Step of Forming Lower Cladding Layer This is a step of forming a lower cladding layer 13 on the surface of the prepared substrate 12. Specifically, as shown in FIG. 2B, a lower layer composition is applied to the surface of the substrate 12 and dried or pre-baked to form a lower layer thin film. And
The lower cladding layer 13 can be formed by curing the lower layer thin film by heating or irradiating light. The heating temperature used for forming the core portion and the cladding layer is not particularly limited, but is usually in the range of 50 ° C to 300 ° C for 1 minute to 6 hours.
Implemented in time. The light is not particularly limited, but light in the ultraviolet to visible region of 200 to 450 nm, preferably light containing ultraviolet light with a wavelength of 365 nm is used. 200 ~
Illuminance at 450nm is 1~1000mW / cm ^2, irradiation amount 0.01~5000m
Exposure is performed by irradiation at J / cm ² , preferably 0.1 to 1000 mJ / cm ² .

Here, as the type of light to be irradiated, visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, γ-ray and the like can be used. Wavelengths containing ultraviolet radiation, preferably from 200 to 400 nm, particularly preferably 365 nm, are preferred. And as the irradiation device, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a lamp light source that simultaneously irradiates a large area such as an excimer lamp, a pulse, a laser light source of continuous light emission, and a light source of either of them Convergent light can be used using a mirror, a lens, and an optical fiber. When an optical waveguide is formed using convergent light, exposure can be performed to the shape of the optical waveguide by moving the convergent light or the irradiation target. Among these light sources, a light source having a high ultraviolet intensity of 365 nm is preferable. For example, a high-pressure mercury lamp is preferable as a lamp light source, and an argon laser is preferable as a laser light source. In the step of forming the lower cladding layer 13, it is preferable to irradiate the entire surface of the thin film with light and to cure the whole.

Here, the lower layer composition is applied by a spin coating method, a dipping method, a spray method, a bar coating method, a roll coating method, a curtain coating method, a gravure printing method, a silk screen method, an ink jet method or the like. Can be used. Among them, it is more preferable to adopt the spin coating method, since a lower layer thin film having a particularly uniform thickness can be obtained.

Further, in order to appropriately adjust the rheological properties of the composition for the lower layer to the coating method, additives other than the surface tension reducing agent may be added as necessary. Further, the lower layer thin film composed of the lower layer composition is preferably pre-baked at 50 to 200 ° C. after application.
In addition, the coating method in the formation process of the lower clad layer,
The improvement of the rheological properties and the like also applies to the step of forming the core portion and the step of forming the upper clad layer described later.

After the exposure, it is preferable to further perform a heat treatment (hereinafter, referred to as “post bake”) so that the entire surface of the coating film is sufficiently cured. The heating conditions vary depending on the composition of the composition for forming an optical waveguide, the types of additives, and the like, but are usually 30 to 400 ° C., preferably 50 to 300 ° C.
C., for example, for 5 minutes to 72 hours. The irradiation amount, type, irradiation device, and the like of the light in the lower clad layer forming step are the same as those in the core part forming step and the upper clad layer forming step described later.

Next, as shown in FIG. 2C, a core composition is applied onto the lower clad layer 13 and dried or further prebaked to form a core thin film 14. Then, FIG.
As shown in (d), with respect to the upper surface of the core thin film 14,
It is preferable to irradiate the light 16 according to a predetermined pattern, for example, via a photomask 19 having a predetermined line pattern. As a result, only the light-irradiated portions are cured, and the remaining uncured portions are removed by development, as shown in FIG. The core portion 15 made of a film can be formed. Irradiation of the light 16 to the core thin film 14 for forming the core portion 15 is performed according to a photomask 19 having a predetermined pattern, and then the unexposed portion is developed with a developing solution. Unnecessary portions are removed, thereby forming the core portion 15. The method of irradiating light in accordance with the predetermined pattern as described above is not limited to a method using a photomask including a light transmitting portion and a non-transmitting portion,
For example, the following methods a to c can be mentioned. a. A method using a means for electro-optically forming a mask image composed of a light transmitting area and a non-transmitting area according to a predetermined pattern using the same principle as that of a liquid crystal display device. b. Using a light guide member made by bundling many optical fibers,
A method of irradiating light via an optical fiber corresponding to a predetermined pattern on the light guide member. c. A method of irradiating a composition while scanning with laser light or convergent light obtained by a converging optical system such as a lens or a mirror.

After the exposure, it is preferable to perform a heat treatment (hereinafter, referred to as “PEB”) to accelerate the curing of the exposed portion. The heating conditions vary depending on the composition of the composition for forming an optical waveguide, the types of additives, and the like, but are usually 30 to 200 ° C, preferably 50 to 150 ° C. On the other hand, before exposure, the coating of the optical waveguide forming composition can be left in a room temperature condition for only 1 to 10 hours to make the core portion semicircular in shape. Therefore,
When it is desired to obtain a semicircular core portion, it is preferable to leave the core portion at room temperature for several hours before exposure. In this manner, the thin film that has been subjected to pattern exposure according to a predetermined pattern and selectively cured can be subjected to development processing by utilizing the difference in solubility between the cured part and the uncured part. Therefore, after the pattern exposure, by removing the uncured portion and leaving the cured portion, the core portion can be formed as a result.

Here, the developing solution includes sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, Methyl diethylamine, ethanolamine, N-methylethanolamine,
N, N-dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, choline, pyrrole, piperidine,
Basic substances such as 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonane and water, methanol, ethanol, propyl alcohol, butanol, A solution diluted with a solvent such as octanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, N-methylpyrrolidone, formamide, N, N-dimethylformamide, N, N-dimethylacetamide can be used. The concentration of the basic substance in the developer is usually 0.05 to 25% by weight, preferably 0.1 to 25% by weight.
It is preferable to set the value in the range of 3.0% by weight.

The developing time is usually from 30 to 600 seconds, and a known developing method such as a puddle method, a dipping method or a shower developing method can be employed. When an organic solvent is used as the developing solution, air drying is performed. When an alkaline aqueous solution is used, running water washing is performed, for example, for 30 to 90 seconds, and air drying is performed using compressed air or compressed nitrogen. By removing the water, a patterned film is formed.

Next, in order to further cure the patterning portion, post-baking is performed by a heating device such as a hot plate or an oven at a temperature of, for example, 30 to 400 ° C. for 5 to 600 minutes to form a cured core portion. Will be. In addition, it is preferable to use an aminopolysiloxane having a higher amino group content than the lower layer composition and the upper layer composition for the core composition. With such a configuration, while the pattern accuracy of the core portion can be further improved, the composition for the lower layer and the composition for the upper layer,
Excellent storage stability can be obtained, and curing can be sufficiently performed with a relatively small amount of light irradiation.

Formation of Upper Cladding Layer Next, the lower cladding layer 13 on which the core portion 15 is formed
An upper layer composition is applied to the surface of the substrate and dried or prebaked to form an upper layer thin film. The upper cladding layer 17 can be formed as shown in FIG. 1 by irradiating the upper thin film with light to cure it. The upper cladding layer obtained by light irradiation is preferably subjected to the above-described post-baking, if necessary. By post-baking, an upper clad layer having excellent hardness and heat resistance can be obtained.

[0060]

EXAMPLES In the following examples, a silicon wafer was used as a base material. The procedure for forming the optical waveguide was performed according to the procedure described above. In this embodiment, the same composition was used for the lower cladding layer and the upper cladding layer. In Example-1 of Table 1, the clad layer was formed by thermosetting. In other examples and comparative examples, the clad layer was cured by light curing. The core portion formed a linear optical waveguide pattern by exposure using a mask. The thickness of the lower cladding layer is 15 μm, the thickness of the core portion is 10 μm, the width is 10 μm, the length is 6 cm, the space between the cores is 20 μm,
The thickness of the upper clad layer was set to 15 μm. The composition of the single mode optical waveguide was designed such that the refractive index of the core portion was 1.003 times higher than the refractive index of the cladding layer.

Evaluation [Evaluation of optical transmission loss and heat cycle resistance] Lower cladding layer 15 μm on silicon wafer, core part thickness 1
0 μm, core part width 10 μm, upper cladding layer 15 μm
The optical waveguide on which the cured layer of m was formed was stored in a constant temperature bath capable of performing a program operation, and a cycle of -20 ° C. for 3 hours → heating 1 hour → 80 ° C. 3 hours → cooling 1 hour was subjected to 100 cycle tests. After the test was completed, the transmission loss at a wavelength of 1.55 μm of the optical waveguide was obtained by the cutback method, and the transmission loss was evaluated by subtracting the connection loss therefrom. Initial transmission loss / (d
B / cm) and the transmission loss / (dB / cm)
Those that were not more than / (dB / cm) were judged as ○, and those that exceeded 0.2 / (dB / cm) were judged as ×.

[Production of Polysiloxane Solution 1 (PS1)] In a container equipped with a stirrer, phenyltrimethoxysilane (76.9 g, 0.39 mol) and methyltrimethoxysilane (101.7 g, 0.75 mol) were added. Mole) and ion-exchanged water (45.9 g,
2.55 mol) and oxalic acid (0.1 g, 1.1 × 10
3 mol), and heated and stirred at 60 ° C. for 6 hours to hydrolyze phenyltrimethoxysilane and methyltrimethoxysilane. Next, propylene glycol monomethyl ether was added into the container, and then methanol produced as a by-product of hydrolysis was removed using an evaporator. Then, a propylene glycol monomethyl ether solution containing polysiloxane whose solid content was finally adjusted to 55% by weight was obtained. This is designated as “polysiloxane solution 1 (PS1)”.

[Production of Polysiloxane Solution 2 (PS2)] In a vessel equipped with a stirrer, phenyltrimethoxysilane (103.65 g, 0.52 mol) and methyltrimethoxysilane (136.99 g, 1.00 Mol) and dimethyldimethoxysilane (24.32 g, 0.20 mol)
Ion-exchanged water (90.0 g, 5.0 mol) having an electric conductivity of 8 × 10 −5 S · cm −1, and oxalic acid (0.15
g, 1.66 × 103 mol) at 60 ° C.
By heating and stirring under the condition of 6 hours, phenyltrimethoxysilane, methyltrimethoxysilane and dimethyldimethoxysilane were hydrolyzed. Then
After propylene glycol monomethyl ether was added into the vessel, methanol produced as a by-product of hydrolysis was removed using an evaporator. And finally the solid content is 5
A propylene glycol monomethyl ether solution containing polysiloxane adjusted to 5% by weight was obtained. This is designated as “polysiloxane solution 2 (PS2)”.

[Production of Polysiloxane Solution 3 (PS3)] (a) Acrylic polymer solution 1 In a vessel equipped with a stirrer, methyl methacrylate (450
g, 4.50 mol), methacryloxypropyltrimethoxysilane (50 g, 0.20 mol), propylene glycol monomethyl ether (600 g), and 2,2′-azobis- (2.4-dimethylvaleronitrile) ( (35 g, 0.14 mol), and then the system is purged with nitrogen. Thereafter, the temperature in the reaction vessel is set at 70 ° C., and the mixture is stirred for 6 hours. Finally, the solid content concentration was adjusted to 45% by weight to obtain a propylene glycol monomethyl ether solution containing an acrylic polymer. This is designated as “acryl polymer solution 1”. (b) Polysiloxane solution 3 Acrylic polymer solution (133.3) was placed in a container equipped with a stirrer.
3g), methyltrimethoxysilane (231.36 g,
1.70 mol), phenyltrimethoxysilane (19
3.48 g, 0.97 mol), having an electric conductivity of 8 × 10
-5 Scm-1 ion-exchanged water (108.48 g, 6.0
Mol) and oxalic acid (0.30 g, 3.32 × 1
After that, phenyltrimethoxysilane, methyltrimethoxysilane, and the acrylic polymer solution were hydrolyzed by heating and stirring at 60 ° C. for 6 hours. Next, propylene glycol monomethyl ether was added into the container, and then methanol produced as a by-product of hydrolysis was removed using an evaporator. And finally, a propylene glycol monomethyl ether solution containing polysiloxane whose solid content was adjusted to 45% by weight was obtained. This is called "polysiloxane solution 3"
(PS3). "

[Production of Acrylic Polymer Solution 2] In a vessel equipped with a stirrer, methyl methacrylate (325 g,
3.25 mol), styrene (25 g, 0.24 mol),
Methacrylic acid (75 g, 0.85 mol), acrylate containing cyclohexene oxide (Cyclomer A200, manufactured by Daicel Chemical Industries, Ltd., 75 g, 0.38 mol), propylene glycol monomethyl ether (600 g), and 2,2′-azobis After containing-(2.4-dimethylvaleronitrile) (35 g, 0.14 mol), the system is purged with nitrogen. Thereafter, the temperature in the reaction vessel is set at 70 ° C., and the mixture is stirred for 6 hours. Finally the solid content concentration is 45% by weight
To obtain a propylene glycol monomethyl ether solution containing an acrylic polymer. This is designated as “acrylic polymer solution 2”.

[Preparation of Curable Composition A for Forming Optical Waveguide for Forming Core] A photoacid generator (Midori Chemical Co., Ltd.) 1 part by weight of TPS-105), 0.005 part by weight of trioctylamine as an acid diffusion controller, and a surface tension reducing agent (SH28PA manufactured by Dow Corning Toray Co., Ltd.)
01 parts by weight were added, mixed uniformly, and filtered with a 0.5 μm filter to obtain a curable composition A for forming an optical waveguide for forming a core portion. The linear expansion coefficient of the cured film formed by irradiating Composition A with light with a high-pressure mercury lamp at a light intensity of 50 mJ / cm ² was 90 ppm / K.

[Preparation of Curable Composition B for Forming Optical Waveguide for Forming Cladding] 100 parts by weight of the above-mentioned polysiloxane solution 2 (PS2) in solid content and 1 part of dibutyltin dilaurate as a curing catalyst were added, and the mixture was uniformly mixed. Mix and add 0.5
By filtering through a μm filter, a curable composition B for forming an optical waveguide for forming a clad layer was obtained. Composition B 2
The linear expansion coefficient of the cured film formed by heating at 00 ° C. for 1 hour is 9
It was 5 ppm / K.

[Preparation of Curable Composition C for Forming Optical Waveguide for Forming Cladding] A photoacid generator (Midori Chemical Co., Ltd.) was added to 100 parts by weight of the above-mentioned polysiloxane solution 2 (PS2) in terms of solid content. 2 parts by weight of TPS-105, photosensitizer (9-
(Hydroxymethylanthracene) 0.7 parts by weight, surface tension reducing agent (SH28PA manufactured by Dow Corning Toray Co., Ltd.)
0.01 part by weight was added, mixed uniformly, and filtered with a 0.5 μm filter to obtain a curable composition C for forming an optical waveguide for forming a clad layer. The linear expansion coefficient of the cured film formed by irradiating Composition A with light at a light intensity of 50 mJ / cm ² using a high-pressure mercury lamp was 95 ppm / K.

[Preparation of Curable Composition D for Forming Optical Waveguide for Forming Clad] A photoacid generator (Midori Chemical Co., Ltd.) was added to 100 parts by weight of the above-mentioned polysiloxane solution 3 (PS3) in terms of solid content. TPS-105) 1 part by weight, photosensitizer (9-
(Hydroxymethylanthracene) 0.2 parts by weight, surface tension reducing agent (SH28PA manufactured by Dow Corning Toray Co., Ltd.)
0.01 part by weight was added, mixed uniformly, and filtered with a 0.5 μm filter to obtain a curable composition D for forming an optical waveguide for forming a clad layer. The linear expansion coefficient of the cured film formed by irradiating Composition A with light with a high-pressure mercury lamp at a light intensity of 50 mJ / cm ² was 110 ppm / K.

[Cured composition E for forming an optical waveguide for forming a core]
Preparation] 1 part by weight of a photoacid generator (TPS-105, manufactured by Midori Kagaku Co., Ltd.) and 100 parts by weight of the above-mentioned acrylic polymer solution 2 in terms of solid content, and 0.1 part of an acid diffusion controller (trioctylamine). 05 parts by weight, photosensitizer (9-hydroxymethylanthracene) 0.2 parts by weight, surface tension reducing agent (SH28PA manufactured by Dow Corning Toray) 0.01
A weight part was added, mixed uniformly, and filtered with a 0.5 μm filter to obtain a curable composition E for forming an optical waveguide for forming a core portion. Composition E was irradiated with a high pressure mercury lamp with a light intensity of 5
The linear expansion coefficient of the cured film formed by light irradiation at 0 mJ / cm ² is 14
It was 0 ppm / K. [Preparation of Curable Composition F for Forming Optical Waveguide for Forming Cladding] Solid content of acrylic polymer solution 1 described above was calculated as 10
0 parts by weight of photoacid generator (Midori Chemical Co., Ltd.)
1 part by weight of TPS-105), 0.2 part by weight of a photosensitizer (9-hydroxymethylanthracene), and 0.01 part by weight of a surface tension reducing agent (SH28PA manufactured by Dow Corning Toray Co., Ltd.) were added. Then, the mixture was filtered through a 0.5 μm filter to obtain a curable composition F for forming an optical waveguide for forming a core portion. Composition F was irradiated with a high-pressure mercury lamp at a light intensity of 50 mJ / c.
linear expansion coefficient of the cured film formed by light irradiation in m ² is 200 ppm /
It was K.

[Evaluation Results of Optical Waveguide] Table 1 shows the results of evaluating optical waveguides formed using the compositions prepared in the examples and comparative examples based on the above-described test method.
From Table 1, the coefficient of linear expansion of the core is 150 ppm / K or less,
An optical waveguide having a difference in linear expansion coefficient between the core portion and the cladding layer of 50 ppm / K or less has good heat cycle resistance, whereas the core portion has a linear expansion coefficient of 150 ppm as shown in the comparative example.
An optical waveguide exceeding ppm / K and having a difference in linear expansion coefficient between the core portion and the cladding layer exceeding 50 ppm / K showed a low heat cycle resistance. From this, it became clear that an optical waveguide excellent in heat cycle resistance can be manufactured by controlling the linear expansion coefficients of the core portion and the cladding layer shown in the present invention.

[0072]

[Table 1] * UV; high-pressure mercury lamp under the atmosphere, curing in light intensity 50 mJ / cm ²

[0073]

According to the present invention, an optical waveguide having excellent heat cycle durability and optical characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an optical waveguide of the present invention.

FIGS. 2A to 2E are partial process diagrams of a method for manufacturing an optical waveguide.

[Explanation of symbols]

12 Substrate 13 Lower cladding layer 14 Core thin film 15 core part 16 rays 17 Upper cladding layer 19 Photomask

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Tomohiro Utaka             Jay 11-2-24 Tsukiji, Chuo-ku, Tokyo             SRL Co., Ltd. F term (reference) 2H047 KA03 PA02 PA21 PA24 PA28                       QA05

Claims (3)

[Claims] 1. A patterned optical waveguide comprising a lower cladding layer, a core portion, and an upper cladding layer, any one of which is formed from a silica-based compound,
An optical waveguide, wherein a linear expansion coefficient β of a core portion is 150 ppm / K or less, and a difference Δβ between linear expansion coefficients of the core portion and the cladding layer is 50 ppm / K or less. 2. The optical waveguide according to claim 1, wherein the optical waveguide is formed on a base material having a linear expansion coefficient β of 100 ppm or less. 3. The method according to claim 1, wherein the silica-based compound is a cured product of at least one compound selected from the group consisting of a hydrolyzable silane compound represented by the following general formula (1), a hydrolyzate thereof and a condensate thereof. The optical waveguide according to claim 1, wherein: RmSi (X) _4-m (1) (R is a non-hydrolyzable organic group having 1 to 12 carbon atoms, X is a hydrolyzable group, and m is 0 to 3)