JP2006036898A - Photocurable composition and optical waveguide using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical waveguide not causing release from a substrate such as a silicon wafer even when used for a long period under heat and cold cycle in which a high temperature state and a low temperature state are repeated and under high-moisture conditions and its forming material. <P>SOLUTION: The photocurable composition comprises (A) a hydrolyzable silane compound represented by general formula: (R<SP>1</SP>)<SB>p</SB>(R<SP>2</SP>)<SB>q</SB>Si(X)<SB>4-p-q</SB>[wherein R<SP>1</SP>s are unhydrolyzable same or different 1-12C organic groups each containing a fluorine atom; R<SP>2</SP>s are unhydrolyzable same or different 1-12C organic group each containing no fluorine atom; Xs are same or different hydrolyzable groups; p is 1 or 2 and q is 0 or 1] or its hydrolyzate or its condensate and (B) a siloxane-based basket-shaped compound having solubility to organic solvents. The composition is used as a forming material for a lower cladding layer 12, etc., of an optical waveguide 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photocurable composition that can be cured by ultraviolet rays or the like, and an optical waveguide formed by using the composition to form at least a portion including an interface with a substrate.

  In the multimedia era, transmission systems that use light as a transmission medium have become public communication networks, LANs (local area networks), and FAs (factory automation) in response to demands for large capacity and high speed information processing in optical communication systems and computers. ), Interconnects between computers, home wiring, etc. The optical waveguide used in these transmission systems is a basic in optical devices, photoelectric integrated circuits (OEICs), optical integrated circuits (optical ICs), etc. for realizing large-capacity information transmission such as movies and moving images and optical computers, for example. It is a component. Optical waveguides have been intensively studied due to the large amount of demand. On the other hand, particularly high performance and low cost products are required.

Conventionally known quartz optical waveguides and polymer optical waveguides are known as such optical waveguides.
Among them, the silica-based optical waveguide has excellent transmission characteristics as compared with the polymer-based optical waveguide, but the vitrification process (at 1200 ° C. or higher) or the etching process performed following the deposition of oxide fine particles. Therefore, strict production conditions for a long time are required for production.
On the other hand, a polymer-based optical waveguide can be easily formed into a thin film by a spin coating method, a dip coating method, or the like, and can be manufactured at a low temperature process by reactive ion etching (RIE) or photolithography. In particular, an optical waveguide using photolithography can be formed more easily in a short time and at a lower cost than a quartz optical waveguide. However, the polymer-based optical waveguide has a problem that transmission characteristics deteriorate when used for a long time under high temperature and high humidity.

Therefore, various proposals have been made in order to improve the performance of the polymer-based optical waveguide.
For example, (A) at least one compound selected from the group consisting of a hydrolyzable silane compound represented by a specific general formula, its hydrolyzate and its condensate, and (B) an organic onium having absorption at a wavelength of 365 nm A radiation curable composition for forming an optical waveguide containing a salt has been proposed (Patent Document 1). An optical waveguide made of this composition maintains good optical properties even when used for a long time under high temperature and high humidity.
JP 2003-185860 A

As described above, when a composition having a specific component composition is used, an optical waveguide that maintains good optical characteristics even when used for a long time under high temperature and high humidity can be formed.
However, the polymer-based optical waveguide also has a problem that when it is used for a long time in an atmosphere (cooling cycle) having a large temperature change, the polymer-based optical waveguide easily peels off from a base material such as a silicon wafer or a glass substrate.
Accordingly, the present invention provides an optical waveguide that does not peel off from a base material such as a silicon wafer and a material for forming the optical waveguide even when used for a long time under a high-temperature and low-temperature cycle where high and low temperatures repeatedly appear. This is the issue.

  As a result of intensive studies to solve the above problems, the present inventors have found that a hydrolyzable silane compound represented by a specific general formula, a hydrolyzate or condensate thereof, and a siloxane that is soluble in an organic solvent The present invention has been completed by finding that an optical waveguide that does not peel off from a substrate can be formed even under severe conditions such as a cooling and heating cycle by using a photocurable composition containing a system cage compound.

That is, the present invention provides the following [1] to [6].
[1]
(A) General formula (1): (R ¹ ) _p (R ² ) _q Si (X) _4-pq (1)
[Wherein, R ¹ represents a nonhydrolyzable identical or different organic group having 1 to 12 carbon atoms containing a fluorine atom, and R ² has 1 to 12 carbon atoms not containing a fluorine atom. Represents a non-hydrolyzable organic group, and X represents the same or different hydrolyzable groups. P is 1 or 2, and q is 0 or 1. ]
And at least one selected from the group consisting of hydrolyzable silane compounds, hydrolysates thereof, and condensates thereof, and (B) a siloxane cage compound having solubility in an organic solvent. A photocurable composition.
[2]
The photocurable composition according to the above [1], wherein the component (B) is a compound having a reactive group.
[3]
The photocurable composition according to the above [2], wherein the reactive group is an oxetanyl group or an epoxy group.
[4]
The photocurable composition according to any one of the above [1] to [3], wherein the compounding amount of the component (B) is 1 to 60 parts by mass per 100 parts by mass in total with the component (A).
[5]
The photocurable composition according to any one of [1] to [4] above, which contains a photoacid generator.
[6]
An optical waveguide formed on a base material, comprising: a core portion that is an optical transmission line; and a clad layer formed around the core portion, and at least the base material of the clad layer An optical waveguide characterized in that a portion including the boundary surface is made of the photocurable composition according to any one of the above [1] to [5].

  According to the photocurable composition of the present invention, an optical waveguide that does not peel off from a base material such as a silicon wafer even when used for a long period of time under a high temperature and low temperature cycle and a high temperature and low temperature cycle. Can be formed.

The component which comprises the photocurable composition of this invention is demonstrated.
[Component (A): Hydrolyzate of silane compound, etc.]
Component (A) used in the present invention has the general formula (1):
(R ¹ ) _p (R ² ) _q Si (X) _4-pq (1)
[Wherein, R ¹ represents a nonhydrolyzable identical or different organic group having 1 to 12 carbon atoms containing a fluorine atom, and R ² has 1 to 12 carbon atoms not containing a fluorine atom. Represents a non-hydrolyzable organic group, and X represents the same or different hydrolyzable groups. P is 1 or 2, and q is 0 or 1. ]
Is a hydrolyzable silane compound (hereinafter also referred to as “hydrolyzable silane compound (1)”), a hydrolyzate thereof, or a condensate thereof.

R ¹ in the general formula (1) is a non-hydrolyzable identical or different organic group having 1 to 12 carbon atoms containing a fluorine atom. In the present specification, the term “non-hydrolyzable” means that it is a property that exists stably as it is under the condition that the hydrolyzable group represented by X is hydrolyzed. Examples of the non-hydrolyzable organic group include a fluorinated alkyl group, a fluorinated aryl group, or a halogen atom such as a deuterium, a chlorine atom, a bromine atom, or an iodine atom in which some or all of these hydrogen atoms are present. An organic group substituted by, and the like.

Such a fluorinated alkyl group has a composition formula: C _{m + n} H _2m F _{2n + 1} [m is an integer of 0 to 5, n is an integer of 1 to 12, and m + n is an integer of 1 to 12. is there. From the viewpoint of further improving the physical properties such as patterning property and crack resistance of the cured product formed from the composition of the present invention, and reducing waveguide loss. General formula: CF ₃ (CF ₂ ) _n-1 (CH ₂ ) _m [m and n are as defined above] A fluorinated alkyl group represented by Examples of the fluorinated alkyl group include a trifluoromethyl group, a trifluoropropyl group, a heptadecafluorodecyl group, a tridecafluorooctyl group, and a nonafluorohexyl group. Among these, a heptadecafluorodecyl group, a tridecafluorooctyl group, a nonafluorohexyl group and the like having a high fluorine content and a long alkyl chain are preferable. Examples of the fluorinated aryl group include a pentafluorophenyl group. In these fluorinated alkyl groups and fluorinated aryl groups, some or all of the hydrogen atoms may be substituted with deuterium, halogen atoms such as chlorine, bromine, and iodine atoms.

R ² in the general formula (1) is a non-hydrolyzable organic group having 1 to 12 carbon atoms that does not contain a fluorine atom. Examples of such non-hydrolyzable organic groups include alkyl groups, aryl groups, aralkyl groups, organic groups containing heteroatoms, organic groups containing polymerizable groups, or some or all of these hydrogen atoms. Examples thereof include organic groups substituted with deuterium, halogen atoms such as chlorine atom, bromine atom and iodine atom. These organic groups may be linear, branched or cyclic.
Here, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, and an octyl group.

Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, a biphenyl group, a deuterated phenyl group, and a halogenated phenyl group.
Examples of the aralkyl group include a benzyl group and a phenylethyl group.
The organic group containing a hetero atom is preferably a non-basic group, and examples thereof include an organic group containing an ether bond, an organic group containing an ester bond, and an organic group containing a sulfide bond.
The organic group containing a polymerizable group is preferably an organic group containing a cationic polymerizable group in the molecule, and examples thereof include an organic group containing a vinyl ether group, an epoxy group, an oxetanyl group, and the like. By introducing the polymerizable group, cationic polymerization can be caused to cure the curable composition more effectively.

X in the general formula (1) is the same or different hydrolyzable group. In the present specification, the hydrolyzable group is hydrolyzed by heating for 1 to 10 hours within a temperature range of 0 to 150 ° C. under atmospheric pressure and in the presence of a hydrolysis catalyst described later and water. A group capable of forming a silanol group or a group capable of forming a siloxane condensate.
Examples of the hydrolyzable group represented by X include an alkoxy group having 1 to 12 carbon atoms, a halogen atom, an amino group, and an acyloxy group.

Here, as a C1-C12 alkoxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a benzyloxy group etc. are mentioned, for example. These alkoxy groups may have a substituent. Examples of the alkoxy group having a substituent include a phenoxy benzyloxy group, a methoxyethoxy group, an acetoxyethoxy group, a 2- (meth) acryloxyethoxy group, a 3- (meth) acryloxypropoxy group, and a 4- (meth) acryloxy group. (Meth) acryloxy group-containing alkoxy groups such as butoxy groups; glycidoxy groups, epoxy groups-containing alkoxy groups such as 2- (3,4-epoxycyclohexyl) ethoxy groups; oxetanyl groups such as methyl oxetanyl methoxy groups and ethyl oxetanyl methoxy groups An alkoxy group; an alkoxy group containing a 6-membered ring ether group such as an oxacyclohexyloxy group and the like can be mentioned.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. However, when the hydrolyzable silane compound (1) having a hydrolyzable group containing a halogen atom is used, hydrolyzable silane is used as necessary from the viewpoint of enhancing the storage stability of the resulting photocurable composition. It is preferable to remove the hydrogen halide produced by hydrolysis of the compound (1) by an operation such as neutralization or distillation.
Examples of the acyloxy group include an acetoxy group.

In the general formula (1), p is 1 or 2, but is preferably 1. Q is 0 or 1, but is preferably 0.
Examples of the hydrolyzable silane compound (1) used in the present invention include trifluoromethyltrimethoxysilane, trifluoromethyltriethoxysilane, 3,3,3-trifluoropropyltrichlorosilane, and methyl-3,3,3. -Trifluoropropyldichlorosilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropylmethyldichlorosilane, 3,3 , 4,4,5,5,6,6,6-nonafluorohexyltrichlorosilane, 3,3,4,4,5,5,6,6,6-nonafluorohexylmethyldichlorosilane, 4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyltrichloro Run, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyltrimethoxysilane, 3,3,4, 4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyltriethoxysilane, 3,3,4,4,5,5,6 6,7,7,8,8,9,9,10,10,10-heptadecafluorodecylmethyldichlorosilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, (pentafluorophenyl) propyltrimethoxysilane , (Pentafluorophenyl) propyltrichlorosilane and the like.
Among these, 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyltriethoxysilane, 3,3, 4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecyltrimethoxysilane, 3,3,4,4,5,5 6,6,7,7,8,8,9,9,10,10,10-nonafluorohexyltrichlorosilane and the like are preferable.

In the present specification, the hydrolyzate of the hydrolyzable silane compound (1) is a hydrolysis in which part or all of the hydrolyzable groups of the hydrolyzable silane compound (1) are changed to silanol groups by the hydrolysis reaction. By reaction mixture is meant. The condensate of the hydrolyzate of the hydrolyzable silane compound (1) means a siloxane condensate obtained by a condensation reaction between silanol groups in the hydrolysis reaction mixture or between a silanol group and a hydrolyzable group. To do.
The weight average molecular weight of the hydrolyzable silane compound (1) hydrolyzate condensate is a value in terms of polystyrene determined by gel permeation chromatography (GPC), preferably 500 to 50,000, more preferably 1. , 10,000 to 10,000. When the value is less than 500, the durability of the cured product made of the composition of the present invention may be lowered. When this value exceeds 50,000, the preservability of the composition of the present invention may be lowered.

  The method for preparing the component (A) is not particularly limited as long as the content of silanol groups in the composition is not too large or too small, but from the viewpoint of controlling the content of silanol groups within the preferred range described below, For example, water is added to a solution obtained by mixing the hydrolyzable silane compound (1), a catalyst, and a solvent at a temperature not higher than the boiling point of each component in the solution in an air atmosphere under atmospheric pressure and stirring. After dropping, it is preferable to follow the method of heating and stirring at 0 ° C. to 150 ° C. for 1 to 24 hours. During the heating and stirring, it is also preferable to concentrate the reaction solution by distillation or replace the solvent as necessary.

  Here, as a catalyst used for preparation of a component (A), if a hydrolysis reaction and a condensation reaction are accelerated | stimulated, there will be no restriction | limiting in particular, For example, catalysts, such as an acid or a base, are mentioned. Examples of the acid include monovalent or polyvalent organic acids such as formic acid, acetic acid and oxalic acid; inorganic acids such as hydrochloric acid, phosphoric acid and sulfuric acid; inorganic salts such as Ti, Zr, Al and B, alkoxides and carboxylates And Lewis acid. Examples of the base include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide and lithium hydroxide; inorganic bases such as ammonia; amines such as trimethylamine, triethylamine, monoethanolamine and diethanolamine Is mentioned. These catalysts may be used alone or in combination of two or more. Although the usage-amount of a catalyst changes also with the kind of catalyst to be used, it is preferable that it is 0.001-5 mass parts normally with respect to 100 mass parts of hydrolysable silane compounds (1), 0.002- It is more preferably 1 part by mass.

The solvent used for the preparation of component (A) is usually an organic solvent having a boiling point under atmospheric pressure in the range of 50 to 200 ° C. and capable of uniformly dissolving each component. Preferred examples include ethers; esters; ketones; hydrocarbons such as aliphatic hydrocarbons and aromatic hydrocarbons; alcohols such as monohydric alcohols and polyhydric alcohols; heteroatom compounds such as nitrogen-containing compounds and sulfur-containing compounds. It is done. These solvents may be used alone or in combination of two or more.
It is preferable that it is 1-1000 mass parts with respect to 100 mass parts of hydrolysable silane compounds (1), and, as for the usage-amount of a solvent, it is more preferable that it is 10-100 mass parts.

  The photocurable composition of the present invention is a hydrolyzable silane compound other than the hydrolyzable silane compound (1), its hydrolyzate, in order to adjust the refractive index, curability, viscosity, etc. of the cured product. And one or more selected from the group consisting of condensates thereof. In this case, a mixture of the hydrolyzable silane compound (1) and a hydrolyzable silane compound other than the hydrolyzable silane compound (1) is subjected to the hydrolysis reaction and the condensation reaction, and both hydrolyzable silane compounds are obtained. A siloxane condensate formed from may be prepared.

  Examples of hydrolyzable silane compounds other than the hydrolyzable silane compound (1) include tetrachlorosilane, tetraaminosilane, tetraacetoxysilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetraphenoxysilane, and tetrabenzyloxysilane. Silane compounds having four hydrolyzable groups such as trimethoxysilane and triethoxysilane; methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriisopropoxy It has three hydrolyzable groups such as silane, ethyltributoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and deuterated methyltrimethoxysilane. Silane compounds having two hydrolyzable groups such as dimethyldichlorosilane, dimethyldiaminosilane, dimethyldiacetoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and dibutyldimethoxysilane .

The content of silanol groups (Si—OH) in the number of bonding groups on all silicon atoms in the component (A) is preferably 10 to 50%, more preferably 20 to 40%. If the silanol group content is outside this range, patterning of the desired shape cannot be obtained during alkali development, or the waveguide loss value may increase when an optical waveguide is formed. Absent.
The silanol group content can be quantified by ²⁹ Si-NMR or the like. For example, each composition is dissolved in deuterated chloroform which is an NMR measurement solvent, and a plurality of silane components having different substituents and bonding groups appearing from −120 ppm to −60 ppm in ²⁹ Si-NMR (based on dimethylsiloxane) The peaks are separated by curve fitting, the mol% of each component is calculated from the area ratio of the peaks, and the number of silanol groups in each component obtained is multiplied to contain silanol groups in the total number of bonding groups on all silicon atoms. The rate (%) is calculated.

［一般式（２）又は（３）中、Ｒ³はフッ素原子を含有する炭素数が１〜１２である非加水分解性の有機基を示し、Ｒ⁴はフッ素原子を含んでいてもよい炭素数が１〜１２である非加水分解性の有機基を示す。なお、Ｒ³とＲ⁴は同一の基であってもよい。］
Ｒ³が示す、フッ素原子を含有する炭素数が１〜１２である非加水分解性の有機基としては、一般式：ＣＦ₃（ＣＦ₂）_n-1（ＣＨ₂）_m ［ｍ及びｎは前記定義のとおりである。］で表される基であるのが好ましい。 Component (A) is a group consisting of structures represented by the following general formulas (2) and (3) from the viewpoint of further improving the physical properties of the cured product, such as patterning properties, crack resistance, and waveguide loss. It is preferable to have at least one or more.

[In General Formula (2) or (3), R ³ represents a non-hydrolyzable organic group having 1 to 12 carbon atoms containing a fluorine atom, and R ⁴ is carbon that may contain a fluorine atom. The nonhydrolyzable organic group whose number is 1-12 is shown. R ³ and R ⁴ may be the same group. ]
The non-hydrolyzable organic group having 1 to 12 carbon atoms containing a fluorine atom represented by R ³ is represented by the general formula: CF ₃ (CF ₂ ) _n-1 (CH ₂ ) _m [m and n are As defined above. ] Is preferable.

［一般式（４）又は（５）中、Ｒ⁵はフェニル基又はフッ素化フェニル基を示し、Ｒ⁶はフッ素原子を含んでいてもよい炭素数が１〜１２である非加水分解性の有機基を示す。なお、Ｒ⁵とＲ⁶は同一の基であってもよい。］ Moreover, a component (A) is at least 1 type in the group which consists of a structure represented by following General formula (4) and (5) from a viewpoint of improving further physical properties, such as patternability of the hardened | cured material, and heat resistance. It is preferable to have the above.

[In General Formula (4) or (5), R ⁵ represents a phenyl group or a fluorinated phenyl group, and R ⁶ represents a non-hydrolyzable organic group having 1 to 12 carbon atoms which may contain a fluorine atom. Indicates a group. R ⁵ and R ⁶ may be the same group. ]

As a hydrolysable silane compound used in order to have the structure represented by these general formula (4) or general formula (5), it is other than a hydrolysable silane compound (1) or a hydrolysable silane compound (1). Among these hydrolyzable silane compounds, compounds having a phenyl group or a fluorinated phenyl group can be mentioned, and among these, phenyltrimethoxysilane, phenyltriethoxysilane, pentafluorophenyltrimethoxysilane and the like are particularly preferable.
Furthermore, the component (A) further improves the physical properties such as patterning property, crack resistance, heat resistance and waveguide loss of the cured product, and further from the viewpoint of controlling the refractive index, the above general formula (2) and It is preferable to have at least one or more of the group consisting of the structure represented by (3) and at least one or more of the group consisting of the structures represented by the general formulas (4) and (5).

[Component (B): Siloxane-based cage compound]
The component (B) used in the present invention is a siloxane cage compound that is soluble in an organic solvent. Component (B) is blended so that an optical waveguide produced using the composition of the present invention does not peel from a substrate such as a silicon wafer even under conditions of a thermal cycle and high humidity.
Here, “having solubility in an organic solvent” means being soluble in at least one of various organic solvents such as isopropyl alcohol, tetrahydrofuran, toluene, cellosolve acetate, and methyl isobutyl ketone. When component (B) is soluble in an organic solvent, a liquid-applicable photocurable composition can be prepared together with component (A) and the like.
“Siloxane-based” means that the main chain is formed by a siloxane bond (Si—O bond).
“Cage-like” means that the structure of the Si—O—Si skeleton is cage-like. In the present invention, by using a compound having a cage-like chemical structure, a base material under a cold cycle and high humidity as compared with the case of using a compound having another structure (for example, a random structure, a ladder structure, etc.) Excellent peeling resistance can be exhibited.

Component (B) includes (a) a structural unit (M unit) in which a silicon atom is bonded to one oxygen atom and three organic groups, and (b) a silicon atom bonded to two oxygen atoms and two organic groups. A structural unit (D unit), (c) a structural unit (T unit) in which a silicon atom is bonded to three oxygen atoms and one organic group, and (d) a silicon atom is bonded to four oxygen atoms. One or more structural units selected from the structural units (Q units) can be included.
In the present invention, an oligomer containing many D unit repeats or an oligomer containing many T unit repeats is preferably used. A substance mainly composed of repeating T units is called silsesquioxane.
The number of silicon atoms in the component (B) compound is preferably 6-12, more preferably 8-12.

The component (B) preferably has a reactive group. The reactive group reacts with the silanol group of the component (A) to generate a soft segment, thereby improving the effect of the present invention (peeling resistance under a thermal cycle).
Examples of the reactive group include a photocationically polymerizable reactive group such as an oxetanyl group and an epoxy group. Among these, an oxetanyl group and an epoxy group are preferable because they are excellent in curability in air and excellent in heat resistance, adhesiveness, chemical resistance, and the like. Epoxy groups include glycidyl groups and alicyclic epoxy groups.
These reactive groups may be bonded to the silicon atoms forming the main skeleton of component (B) via a chemical structure such as an alkylene group or an ether structure.
An example of an organic group containing an oxetanyl group as a terminal group is represented by the following formula. The ethyl group in the formula may be a hydrogen atom or another alkyl group having 1 to 6 carbon atoms. Further, the propylene group in the formula may be another alkylene group having 1 to 6 carbon atoms.

［式中のＲは、各々独立して、オキセタニル基を末端基として含む有機基、エポキシ基を末端基として含む有機基、水素原子、アルキル基、シクロアルキル基、アルケニル基、アラルキル基、アリール基、ケイ素原子含有基等からなる群より選ばれる基である。ただし、Ｒを構成する炭素原子の数は、好ましくは１〜２０である。また、Ｒを構成するケイ素原子の数は、好ましくは１〜１０である。］ An example of the component (B) is represented by the following formula.

[In the formula, each R is independently an organic group containing an oxetanyl group as a terminal group, an organic group containing an epoxy group as a terminal group, a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group. And a group selected from the group consisting of silicon atom-containing groups. However, the number of carbon atoms constituting R is preferably 1-20. The number of silicon atoms constituting R is preferably 1-10. ]

This example has a cubic Si-O-Si skeleton in which two sets of four silicon atoms arranged in a square are opposed to each other with a predetermined distance, but as another example, it is arranged in a pentagon. Two sets of five silicon atoms that are opposed to each other with a predetermined distance and having a Si—O—Si skeleton containing 10 silicon atoms, and six silicon atoms arranged in a hexagonal shape Examples thereof include two sets having a Si—O—Si skeleton containing 12 silicon atoms, which are opposed to each other at a predetermined distance.
In addition, as component (B), what does not contain the location where the bond of a silicon atom and an oxygen atom was cut | disconnected at all (completely condensed cage compound), and what contains the location where the bond of a silicon atom and an oxygen atom was cut | disconnected Any of (partially cleaved cage compound) may be used, but it is preferable to use a fully condensed cage compound.

  The amount of component (B) is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and particularly preferably 5 to 45 parts by mass per 100 parts by mass in total with component (A). When the blending amount is less than 1 part by mass, the optical waveguide made of the composition of the present invention may be peeled off from the substrate under the thermal cycle condition. When the blending amount exceeds 60% by mass, the cured film may become brittle.

[Photoacid generator]
The photocurable composition of the present invention can contain a photoacid generator.
When the composition containing the photoacid generator is irradiated with radiation, the photoacid generator is decomposed to release an acidic active substance that photocures the composition.
Here, examples of the radiation include visible light, ultraviolet rays, infrared rays, X-rays, electron beams, α rays, and γ rays. However, it is preferable to use ultraviolet rays from the viewpoint of having a constant energy level, a high curing rate, and a relatively inexpensive and compact irradiation apparatus.

Examples of the photoacid generator include an onium salt having a structure represented by the following general formula (6), a sulfonic acid derivative having a structure represented by the following general formula (7), and the like.
_{^{[R 7 a R 8 b R}} 9 c R 10 d W] + m [MZ m + n] -m (6)
[In General Formula (6), the cation is an onium ion, W is S, Se, Te, P, As, Sb, Bi, O, I, Br, Cl, or —N≡N, and R ⁷ , R ⁸ , R ⁹ and R ¹⁰ 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. 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, and Co. Z is, for example, a halogen atom or an aryl group such as F, Cl, Br, etc., m is the net charge of the halide complex ion, and n is the valence of M. ]

Q _s- [S (= O) ₂ -R ¹¹ ] _t (7)
[In the general formula (7), Q is a monovalent or divalent organic group, R ¹¹ is a monovalent organic group having 1 to 12 carbon atoms, the subscript s is 0 or 1, and the subscript t is 1 or 2. is there. ]

(1) Onium salt Specific examples of the anion [MZ _{m + n} ] in the general formula (6) include tetrafluoroborate (BF ₄ ⁻ ), hexafluorophosphate (PF ₆ ⁻ ), hexafluoroantimonate (SbF ₆ ⁻ ), Examples include hexafluoroarsenate (AsF ₆ ⁻ ), hexachloroantimonate (SbCl ₆ ⁻ ), tetraphenyl borate, tetrakis (trifluoromethylphenyl) borate, tetrakis (pentafluoromethylphenyl) borate and the like.
Further, instead of the anion _{[MZ m + n]} in the general formula (6), the general formula ^- it is also preferable to use the anion represented by _[MZ n OH]. Furthermore, perchlorate ion (ClO ₄ ⁻ ), trifluoromethane sulfonate ion (CF ₃ SO ₄ ⁻ ), fluorosulfonate ion (FSO ₄ ⁻ ), toluene sulfonate ion, trinitrobenzene sulfonate anion, trinitrotoluene sulfonate Onium salts having other anions such as anions can also be used.

［一般式（８）中、Ｒ^１２およびＲ^１３は、それぞれ独立して水素原子又はアルキル基、Ｒ^１４は水酸基または−ＯＲ^１５（但し、Ｒ^１５は１価の有機基である。）を示し、ａは４〜７の整数、ｂは１〜７の整数である。ナフタレン環への各置換基の結合位置は特に限定されない。］
［Ｒ^１６−Ｐｈ^１−Ｉ^＋−Ｐｈ^２−Ｒ^１７］［Ｙ⁻］ （９）
［一般式（９）中、Ｒ^１６およびＲ^１７は、それぞれ１価の有機基であり、同一でも異なっていてもよく、Ｒ^１６およびＲ^１７の少なくとも一方は、炭素数が４以上のアルキル基を有しており、Ｐｈ^１およびＰｈ^２はそれぞれ芳香族基であり、同一でも異なっていてもよく、Ｙ⁻は１価の陰イオンであり、周期律表３族、５族のフッ化物陰イオンもしくは、ＣｌＯ_４ ⁻、ＣＦ_３ＳＯ_３ ⁻から選ばれる陰イオンである。］ The onium salt is preferably an aromatic onium salt, particularly preferably a triarylsulfonium salt, a compound represented by the following general formula (8), a diaryl iodonium salt represented by the following general formula (9) or a triaryl iodonium. It is salt.

[In General Formula (8), R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group, R ¹⁴ represents a hydroxyl group or —OR ¹⁵ (where R ¹⁵ is a monovalent organic group). , A is an integer of 4-7, b is an integer of 1-7. The bonding position of each substituent to the naphthalene ring is not particularly limited. ]
^{[R 16 -Ph 1 -I + -Ph} 2 -R 17] [Y -] (9)
[In General Formula (9), R ¹⁶ and R ¹⁷ are each a monovalent organic group and may be the same or different, and at least one of R ¹⁶ and R ¹⁷ is an alkyl group having 4 or more carbon atoms. And Ph ¹ and Ph ² are each an aromatic group, which may be the same or different, Y ⁻ is a monovalent anion, and is a group 3 or group 5 fluoride anion in the periodic table. An ion or an anion selected from ClO ₄ ⁻ and CF ₃ SO ₃ ^— . ]

Examples of the compound represented by the general formula (8) include 4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-butoxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 1- (4,7- And dihydroxy) -naphthyltetrahydrothiophenium trifluoromethanesulfonate, 1- (4,7-di-t-butoxy) -naphthyltetrahydrothiophenium trifluoromethanesulfonate, and the like.
Further, as the diaryl iodonium salt, specifically, (4-n-decyloxyphenyl) phenyl iodonium hexafluoroantimonate, [4- (2-hydroxy-n-tetradecyloxy) phenyl] phenyl iodonium hexafluoroantimonate [4- (2-hydroxy-n-tetradecyloxy) phenyl] phenyliodonium trifluorosulfonate, [4- (2-hydroxy-n-tetradecyloxy) phenyl] phenyliodonium hexafluorophosphate, [4- (2 -Hydroxy-n-tetradecyloxy) phenyl] phenyliodonium tetrakis (pentafluorophenyl) borate, bis (4-t-butylphenyl) iodonium hexafluoroantimonate, bis (4-t-butylphenyl) Iodonium hexafluorophosphate, bis (4-t-butylphenyl) iodonium trifluorosulfonate, bis (4-t-butylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) Examples thereof include one or a combination of two or more of iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium hexafluorophosphate, bis (dodecylphenyl) iodonium trifluoromethylsulfonate, and the like.

(2) Sulphonic acid derivatives The sulfonic acid derivatives represented by the general formula (7) include disulfones, disulfonyldiazomethanes, disulfonylmethanes, sulfonylbenzoylmethanes, imide sulfonates, benzoin sulfonates, 1-oxy Examples include sulfonates of 2-hydroxy-3-propyl alcohol, pyrogallol trisulfonates, benzyl sulfonates, and the like.
Among these, imide sulfonates are preferable, and trifluoromethyl sulfonate derivatives are more preferable.

  Although the compounding quantity of a photo-acid generator is not restrict | limited in particular, Preferably it is 0.01-10 mass parts with respect to a total of 100 mass parts of a component (A) and a component (B), More preferably, it is 0. .1 to 5 parts by mass. If the blending amount is less than 0.01 parts by mass, the photocurability tends to decrease and a sufficient curing rate tends not to be obtained. If the blending amount exceeds 10 parts by mass, the optical properties of the cured product comprising the composition of the present invention may be adversely affected.

[Acid diffusion control agent]
The photocurable composition of the present invention can contain an acid diffusion controller.
An acid diffusion control agent is defined as a compound having an action of controlling the diffusion of an acidic active substance generated from a photoacid generator by light irradiation in a coating and suppressing a curing reaction in a non-irradiated region. However, in order to distinguish from a photoacid generator by definition, an acid diffusion controller is a compound that does not have an acid generating function.
By adding such an acid diffusion controller, the photocurable composition can be effectively cured and the pattern accuracy can be improved.

As the type of the acid diffusion controller, a nitrogen-containing organic compound whose basicity does not change by exposure or heat treatment during the formation process is preferable.
Examples of such nitrogen-containing organic compounds include compounds represented by the following general formula (10).
NR ¹⁸ R ¹⁹ R ²⁰ (10)
[In General Formula (10), R ¹⁸ , R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group. To express. ]

Other nitrogen-containing organic compounds include diamino compounds having two nitrogen atoms in the same molecule, diamino polymers having three or more nitrogen atoms, amide group-containing compounds, urea compounds, nitrogen-containing heterocycles. A compound etc. can be mentioned.
Specific examples of the nitrogen-containing organic compound include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; di-n-butylamine, di-n -Dialkylamines such as pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine; triethylamine, tri-n-propylamine , Tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, etc. Amines; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, - methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, aromatic amines such as 1-naphthylamine; can be mentioned ethanolamine, diethanolamine, alkanolamines such as triethanolamine and the like.
In addition, an acid diffusion control agent can also be used individually by 1 type, or can also be used in mixture of 2 or more types.

The compounding amount of the acid diffusion controller is preferably 0.001 to 15 parts by mass, more preferably 0.005 to 5 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B).
When the blending amount is less than 0.001 part by mass, the pattern shape and dimensional reproducibility of the optical waveguide may be lowered depending on the process conditions. When this compounding quantity exceeds 15 mass parts, the photocurability of a curable composition may fall.

[Basic compounds]
The curable composition of the present invention can contain a basic compound.
As the basic compound, a compound (base generator) that releases a basic active substance capable of curing the curable composition of the present invention in response to an external stimulus such as radiation or heat is used. preferable.
Examples of such basic compounds include photobase generators and thermal base generators. Among these, a photobase generator is preferable from the viewpoint of storage stability.
Examples of photobase generators include 2-nitrobenzyl N-cyclohexyl carbamate (commercial product name: NBC-101, manufactured by Midori Chemical Co., Ltd.), triphenylsulfonium hydroxide (commercial product name: TPS-OH, Midori Chemical Co., Ltd.) Company), anisoin N-cyclohexyl carbamate (commercial product name: ANC-101, manufactured by Midori Chemical Co., Ltd.), nifedipine (manufactured by Tokyo Chemical Industry Co., Ltd.), and the like.
Examples of the thermal base generator include Nt-butoxycarbonyl-2-phenylbenzimidazole, Nt-butoxycarbonyldicyclohexylamine and the like.
Although the compounding quantity of a basic compound is not restrict | limited in particular, Preferably it is 5 mass parts or less with respect to a total of 100 mass parts of a component (A) and a component (B). When the blending amount exceeds 5 parts by mass, cracks are likely to occur in the cured film due to rapid curing, which is not preferable.

[solvent]
The photocurable composition of the present invention can improve storage stability by blending a solvent, can impart an appropriate viscosity, and has a uniform film thickness (for example, The lower cladding layer of the optical waveguide can be formed.
Such a solvent can dissolve both the component (A) and the component (B). What is necessary is just to determine the kind of solvent suitably according to the kind of component (B). Examples of the solvent include isopropyl alcohol, tetrahydrofuran, toluene, cellosolve acetate, methyl isobutyl ketone and the like as described in the description of the component (B).
The blending amount of the solvent is preferably 1 to 300 parts by mass, more preferably 2 to 200 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B). When the blending amount is within this range, the storage stability of the composition can be improved, an appropriate viscosity can be imparted, and a cured film having a uniform film thickness can be formed.

Furthermore, the composition of the present invention includes, for example, a thermal acid generator, a reactive diluent, a radical generator (photopolymerization initiator), a photosensitizer, a metal, as long as the objects and effects of the present invention are not impaired. Alkoxide, inorganic fine particles, dehydrating agent, leveling agent, polymerization inhibitor, polymerization initiation aid, wettability improver, surfactant, plasticizer, ultraviolet absorber, antioxidant, antistatic agent, silane coupling agent, high It is also preferable to add a molecular additive or the like.
In order to prepare the photocurable composition of the present invention, the components described above may be mixed and stirred according to a conventional method.
The viscosity of the composition of the present invention is preferably 5 to 5000 mPa · s, more preferably 10 to 1000 mPa · s at 25 ° C. When the viscosity exceeds 5000 mPa · s, it may be difficult to form a coating film having a uniform thickness, which is not preferable. The viscosity of the photocurable composition of the present invention can be appropriately adjusted by changing the blending amount of the solvent.

Hereinafter, an example of an optical waveguide formed using the photocurable composition of the present invention will be described with reference to the drawings as appropriate. FIG. 1 is a cross-sectional view schematically showing an example of the optical waveguide of the present invention, and FIG. 2 is a flowchart showing an example of the method for manufacturing the optical waveguide of the present invention.
[1. Structure of optical waveguide]
In FIG. 1, an optical waveguide 24 includes a substrate 10, a lower cladding layer 12 formed on the upper surface of the substrate 10, a core portion 20 having a specific width formed on the upper surface of the lower cladding layer 12, The upper clad layer 22 is formed by being laminated on the core portion 20 and the lower clad layer 12. The core portion 20 is embedded in the lower cladding layer 12 and the upper cladding layer 22 that form the outer shape of the optical waveguide 24.
The thicknesses of the lower cladding layer, the core portion, and the upper cladding layer are not particularly limited. For example, the thickness of the lower cladding layer is 1 to 200 μm, the thickness of the core portion is 3 to 200 μm, and the thickness of the upper cladding layer. Is determined to be 1 to 200 μm. Although the width | variety of a core part is not specifically limited, For example, it is 1-200 micrometers.
The refractive index of the core portion needs to be larger than any of the refractive indexes of the lower cladding layer and the upper cladding layer. For example, for light with a wavelength of 400 to 1,600 nm, the refractive index of the core portion is 1.420 to 1.650, the refractive indexes of the lower cladding layer and the upper cladding layer are 1.400 to 1.648, and The refractive index of the core portion is preferably at least 0.1% greater than the refractive index of any of the two cladding layers.

[2. Manufacturing method of optical waveguide]
The method for manufacturing the optical waveguide 24 includes a step of forming the lower clad layer 12, a step of forming the core portion 20, and a step of forming the upper clad layer 22. Of these three steps, at least the step of forming the lower cladding layer is a step of forming a cured product by irradiating the photocurable composition of the present invention with light.
In addition, the composition for forming each part of the lower clad layer 12, the core part 20, and the upper clad layer 22 constituting the optical waveguide is respectively a lower layer composition, a core composition, and an upper layer composition for convenience. Called.

(1) Preparation of material The component composition of each of the lower layer composition, the core composition and the upper layer composition is such that the refractive index relationship between the lower cladding layer 12, the core portion 20 and the upper cladding layer 22 is optical. It is determined so as to satisfy the conditions required for the waveguide. Specifically, two or three kinds of photocurable compositions having a difference in refractive index of an appropriate size are prepared, and among these, a photocurable composition that gives a cured film having the highest refractive index is used as a core. And other photocurable compositions are used as the lower layer composition and the upper layer composition. The lower layer composition and the upper layer composition are preferably the same photocurable composition (the composition of the present invention) in terms of economy and production management. Moreover, the composition of the present invention (however, a refractive index higher than that of the lower layer composition and the upper layer composition) can be used for the core composition.

(2) Preparation of Substrate As shown in FIG. 2A, a substrate 10 having a flat surface is prepared as a base material for forming an optical waveguide. The type of the substrate 10 is not particularly limited, and for example, a silicon wafer or a glass substrate can be used.
(3) Formation process of lower clad layer In this process, the lower clad layer 12 is formed on the surface of the substrate 10. Specifically, as shown in FIG. 2B, the lower layer composition (the composition of the present invention) is applied to the surface of the substrate 10, and dried or prebaked to form the lower layer thin film. The lower layer thin film is irradiated with light and cured to form a lower cladding layer 12 that is a cured body. In the step of forming the lower clad layer 12, it is preferable to irradiate the entire surface of the thin film with light and harden the whole.
Here, as a coating method of the composition for the lower layer, any of spin coating method, dipping method, spray method, bar coating method, roll coating method, curtain coating method, gravure printing method, silk screen method, ink jet method, etc. The method can be used. Among these, since a thin film for a lower layer having a uniform thickness can be obtained, it is preferable to employ a spin coating method.
The coating method in the lower clad layer forming step is the same in the core portion forming step and the upper clad layer forming step, which will be described later.

The light for forming the lower clad layer is not particularly limited, but light in the ultraviolet to visible region of 200 to 450 nm, preferably light including ultraviolet light having a wavelength of 365 nm is usually used. Irradiation at wavelengths 200~450nm, the illuminance is 1~1000mW / cm ^2, irradiation amount 0.01~5000mJ / cm ^2, is preferably carried out such that the 0.1~1000mJ / cm ² exposure .

  Visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays and the like can be used as the type of light to be irradiated, but from the industrial versatility of the light source, preferably 200 to 400 nm, particularly A wavelength including ultraviolet rays of 365 nm is preferable. As an irradiation device, for example, from a lamp light source that simultaneously irradiates a wide area such as a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, an excimer lamp, and a laser light source such as a pulse, continuous light emission, or both, What produces a converging light using a mirror, a lens, and an optical fiber can be used.

It is preferable to further perform heat treatment (post-bake) so that the entire coating film is sufficiently cured after exposure. Although this heating condition changes with component composition etc. of a photocurable composition, it is 30-400 degreeC normally, Preferably it is 50-300 degreeC, for example, what is necessary is just to set it as the heating time for 5 minutes-72 hours.
The light irradiation amount, type, and light (ultraviolet) irradiation device in the lower clad layer forming step are the same in the core portion forming step and the upper clad layer forming step, which will be described later.

(4) Core Part Formation Step Next, as shown in FIG. 2 (c), the core composition is applied onto the lower cladding layer 12 and dried (and prebaked) to form the core thin film 14. Form. Thereafter, as shown in FIG. 2D, the upper surface of the core thin film 14 is irradiated (exposed) with light 16 through a photomask 18 having a predetermined line pattern, for example, according to a predetermined pattern. Do. As a result, only the portion irradiated with light in the core thin film 14 is cured, so that other uncured portions are developed and removed, as shown in FIG. On the lower clad layer 12, the core portion 20 made of a patterned cured film can be formed.
The details of the development processing in this step are as follows.
The development process is carried out in accordance with a predetermined pattern, and for the thin film selectively cured, using the difference in solubility between the cured portion and the uncured portion, only the uncured portion is developed using a developer. The removal is performed. That is, after pattern exposure, the uncured portion is removed and the cured portion is left, resulting in the formation of the core portion.

As the developer used for the development processing, an organic solvent, or sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, Triethylamine, methyldiethylamine, N-methylpyrrolidone, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, 1,8-diazabicyclo [5.4.0] -7- An alkaline aqueous solution composed of alkalis such as undecene and 1,5-diazabicyclo [4.3.0] -5-nonane can be used.
In addition, when using aqueous alkali solution as a developing solution, the density | concentration is 0.05-25 mass% normally, Preferably it is 0.1-3.0 mass%. Moreover, it is also preferable to add an appropriate amount of a water-soluble organic solvent such as methanol or ethanol, a surfactant or the like to the alkaline aqueous solution and use it as a developer.
The development time is usually 30 to 600 seconds. As a developing method, a known method such as a liquid piling method, a dipping method, or a shower developing method can be employed.
When an organic solvent is used as the developer, it is directly air-dried. When an alkaline aqueous solution is used as the developer, it is washed with running water, for example, for 30 to 90 seconds, and then air-dried with compressed air or compressed nitrogen. By doing so, the organic solvent or moisture is removed, and a patterned thin film is formed.
After the formation of the patterned thin film (patterning portion), in order to further cure the patterning portion, a post-baking process is performed using a heating device such as a hot plate or an oven at a temperature of 30 to 400 ° C. for 5 to 600 minutes, for example. In this case, the core portion 20 that is a cured body is formed.

In this step, the method of irradiating light according to a predetermined pattern is not limited to the method using the photomask 18 composed of a light transmitting portion and a non-transmitting portion, and for example, any of the methods a to c shown below May be adopted.
a. A method using electro-optical means for forming a mask image composed of a light transmitting region and a light non-transmitting region in accordance with a predetermined pattern using the same principle as that of a liquid crystal display device.
b. A method of irradiating light through an optical fiber corresponding to a predetermined pattern in the light guide member using a light guide member formed by bundling a large number of optical fibers.
c. A method of irradiating a photosensitive resin composition while scanning a laser beam or convergent light obtained by a condensing optical system such as a lens or a mirror.

(5) Formation process of upper clad layer The upper layer composition is applied to the surfaces of the core portion 20 and the lower clad layer 12, and dried or prebaked to form an upper layer thin film. When the upper thin film is cured by irradiation with light, an upper cladding layer 22 is formed as shown in FIG. The upper clad layer 22 is preferably post-baked in the same manner as in the above-described lower clad layer forming step, if necessary. If post-baking is performed, the upper clad layer 22 having large hardness and excellent heat resistance can be obtained.

Hereinafter, the present invention will be specifically described by way of examples.
[Example 1]
In a flask equipped with a stirrer and a reflux tube, phenyltrimethoxysilane (30.79 g), 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10 , 10,10-heptadecafluorodecyltriethoxysilane (22.64 g), tetraethoxysilane (4.62 g), 1-methoxy-2-propanol (29.93 g) and oxalic acid (0.04 g) are added. After stirring, the resulting solution was heated to 60 ° C. Then, distilled water (11.98 g) was added dropwise, and after completion of the addition, the mixture was stirred at 120 ° C. for 6 hours to produce a siloxane oligomer.
Subsequently, a siloxane cage compound having an oxetanyl group (silsesquioxane derivative having T units and D units as main constituent units; trade name: “OX-SQ SI-20”, manufactured by Toagosei Co., Ltd.) It is added in an amount of 10 parts by mass in a total of 100 parts by mass with the oligomer (solid content), and 1- (4,7-di-t-butoxy) -naphthyltetrahydrothiophenium trifluoro as a photoacid generator. Add 0.32 g of romethanesulfonate, 0.03 g of tri-n-octylamine as an acid diffusion control agent, and cellosolve acetate in such an amount that the final solid content concentration in the composition is 65% by mass. A photocurable composition was obtained.
Next, the obtained photocurable composition was applied onto the surface of a silicon substrate with a spin coater, dried at 120 ° C. for 10 minutes, and then exposed to ultraviolet light having a wavelength of 365 nm and an illuminance of 6 mW / cm ² by an exposure machine (Photo Canon). (Aligner) for 3 minutes. Furthermore, the cured film was produced by heating at 200 degreeC for 1 hour.
[Examples 2 to 5, Comparative Example 1]
A curable composition and a cured film were obtained in the same manner as in Example 1 except that the addition amount of the siloxane-based cage compound was changed to that shown in Table 1.

[Evaluation of physical properties]
The physical property of the cured film which consists of the obtained photocurable composition was evaluated as follows.
(1) Thermal shock test A cured film on a silicon substrate was prepared as 100 chips for each of the various compositions (Examples 1 to 5, Comparative Example 1), and the temperature was 85 ° C. and the relative humidity was 85%. After being allowed to stand for 2000 hours under the above conditions, it was left for 24 hours at a temperature of 25 ° C. and a relative humidity of 50%, and it was visually confirmed whether or not peeling occurred from the silicon substrate. Of 100 samples, 0 to 10 were peeled off, “◎”, 11-20 were peeled from “◯”, 21-30 were peeled from “ [Delta] ", a case where peeling occurred on 31 sheets or more was marked as" x ".
The results are shown in Table 1.

It is sectional drawing which shows an example of the optical waveguide of this invention typically. It is a flowchart which shows an example of the manufacturing method of the optical waveguide of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Substrate 12 Lower clad layer 14 Core thin film 16 Light 18 Photomask 20 Core portion 22 Upper clad layer 24 Optical waveguide

Claims (6)

(A) General formula (1):
(R ¹ ) _p (R ² ) _q Si (X) _4-pq (1)
[Wherein, R ¹ represents a nonhydrolyzable identical or different organic group having 1 to 12 carbon atoms containing a fluorine atom, and R ² has 1 to 12 carbon atoms not containing a fluorine atom. Represents a non-hydrolyzable organic group, and X represents the same or different hydrolyzable groups. P is 1 or 2, and q is 0 or 1. ]
And at least one selected from the group consisting of a hydrolyzable silane compound represented by: a hydrolyzate thereof, and a condensate thereof;
(B) A photocurable composition comprising a siloxane cage compound having solubility in an organic solvent.   The photocurable composition according to claim 1, wherein the component (B) is a compound having a reactive group.   The photocurable composition according to claim 2, wherein the reactive group is an oxetanyl group or an epoxy group.   The photocurable composition according to any one of claims 1 to 3, wherein the amount of the component (B) is 1 to 60 parts by mass per 100 parts by mass in total with the component (A).   The photocurable composition of any one of Claims 1-4 containing a photo-acid generator. An optical waveguide formed on a base material, comprising: a core portion that is an optical transmission line; and a clad layer formed around the core portion, and at least the base material of the clad layer An optical waveguide characterized in that a portion including the boundary surface is made of the photocurable composition according to any one of claims 1 to 5.

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