JP2006063288A - Photosensitive resin composition, optical waveguide and method for producing the same waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition capable of forming an optical waveguide having little waveguide loss even when transmitting light in a visible light area. <P>SOLUTION: The photosensitive resin composition comprises (A) a copolymer having a structure represented by general formula (1) [wherein R<SP>1</SP>, R<SP>2</SP>and R<SP>3</SP>are each independently a hydrogen atom or 1-12C alkyl group; X is a group having a carboxyl group; Y is a group having a polymerizable reactive group; Z is an organic group other than X and Y; l, n and m are each a recurring unit number excluding 0], (B) a compound having two or more polymerizable reactive groups in the molecule and (C) a photopolymerization initiator and the resin composition has 0.01-0.3 mass% component C content. The photosensitive resin composition is used as a raw material for core part 20 and clad layers 12 and 22 constituting the optical waveguide 24. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photosensitive resin composition for an optical waveguide, and more particularly to a photosensitive resin composition for forming an optical waveguide having excellent transmission characteristics for light in the visible light region.

In the multimedia era, optical waveguides are attracting attention as optical transmission media because of the demand for large capacity and high speed information processing in optical communication systems and computers. A quartz optical waveguide, which is a typical example of a conventional optical waveguide, is generally manufactured by the following steps (1) to (3).
(1) A lower cladding layer made of a glass film is formed on a silicon substrate by a technique such as flame deposition (FHD) or CVD.
(2) An inorganic thin film having a higher refractive index is formed on the lower cladding layer, and the thin film is patterned by reactive ion etching (RIE) to form a core portion.
(3) Further, an upper clad layer is formed by a flame deposition method.
However, such a method for manufacturing a silica-based optical waveguide has problems such as requiring a special manufacturing apparatus and a long manufacturing time.
In order to solve these problems, a predetermined amount of light is irradiated to a predetermined portion of the silicone composition containing a photopolymerizable component to cure the portion, and then the unexposed portion is developed. Thus, a method of manufacturing an optical waveguide by forming a core portion or the like has been proposed (Patent Document 1).
This method is advantageous in that the optical waveguide can be manufactured in a short time and at a low cost as compared with the conventional method for manufacturing a silica-based optical waveguide. However, this method has limitations such as the need to use a special silicone-based oligomer.
On the other hand, (A) a vinyl polymer having a carboxyl group, a polymerizable group and other organic groups, (B) a compound having two or more polymerizable reactive groups in the molecule, and (C) a radiation polymerization initiator , A radiation curable composition for forming an optical waveguide has been proposed (Patent Document 2). According to this composition, an optical waveguide having high shape accuracy and excellent transmission characteristics can be produced.
As a specific example of this composition, an example containing 1.0% by mass of a polymerization initiator is disclosed. In this case, a low waveguide loss of 0.3 to 0.4 dB / cm is obtained for light having a wavelength of 850 nm.
JP2000-180643 JP2003-195079

According to the knowledge found by the present inventors, the optical waveguide formed using the radiation curable composition for forming an optical waveguide containing the above-mentioned components (A) to (C) is in the visible light region (for example, wavelength 405 nm). When light is transmitted, the waveguide loss tends to be larger than when light in the near-infrared region (for example, wavelength 850 nm) is transmitted.
Therefore, an object of the present invention is to provide a photosensitive resin composition capable of forming an optical waveguide with little waveguide loss even when transmitting light in the visible light region.

［式中、Ｒ^１、Ｒ^２、Ｒ^３は各々独立して水素原子または炭素数１〜１２のアルキル基、Ｘはカルボキシル基を有する基、Ｙは重合性反応基を有する基、ＺはＸおよびＹ以外の有機基であり、ｌ、ｎ、ｍは各々、０ではない繰り返し単位数を示す。］
（Ｂ）分子中に２個以上の重合性反応基を有する化合物、および
（Ｃ）光重合開始剤
を含有し、かつ、前記成分（Ｃ）の含有率が０．０１〜０．３質量％であることを特徴とする感光性樹脂組成物。
［２］
（Ｄ）有機溶剤を含有する前記［１］の感光性樹脂組成物。
［３］
前記成分（Ｂ）の重合性反応基が、エチレン性不飽和基または環状エーテルである前記［１］又は［２］の感光性樹脂組成物。
［４］
下部クラッド層と、コア部分と、上部クラッド層とを含む光導波路であって、前記下部クラッド層、コア部分および上部クラッド層の少なくとも一つが、前記［１］〜［３］のいずれかの感光性樹脂組成物の硬化物からなることを特徴とする光導波路。
［５］
下部クラッド層と、コア部分と、上部クラッド層とを含む光導波路の製造方法であって、下部クラッド層を形成する工程と、コア部分を形成する工程と、上部クラッド層を形成する工程とを含み、かつ、これらの少なくとも一つの工程が、前記［１］〜［３］のいずれかの感光性樹脂組成物を光照射して硬化させる光硬化工程であることを特徴とする光導波路の製造方法。
［６］
前記光硬化工程が、波長２５４ｎｍにおける照度０．１〜３０ｍＷ／ｃｍ^２の光を照射することにより行なわれる前記［５］の光導波路の製造方法。 As a result of intensive studies to solve the above problems, the present inventor has found that, in the above-described conventional radiation-curable composition for forming an optical waveguide, if the blending amount of the polymerization initiator is limited within a predetermined range, visible light can be obtained. Even when transmitting light in a region, the waveguide loss can be kept low, and when an optical waveguide is manufactured using the composition thus prepared, the illuminance at a wavelength of 254 nm is zero. The present invention was completed by finding out that it is appropriate to photocure the composition using 1 to 30 mW / cm ² of light.
That is, the present invention provides the following [1] to “6”.
[1]
(A) a copolymer having a structure represented by the following general formula (1):

[Wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, X is a group having a carboxyl group, Y is a group having a polymerizable reactive group, and Z is X And an organic group other than Y, and each of l, n, and m represents a number of repeating units other than 0. ]
(B) a compound having two or more polymerizable reactive groups in the molecule, and (C) a photopolymerization initiator, and the content of the component (C) is 0.01 to 0.3% by mass The photosensitive resin composition characterized by the above-mentioned.
[2]
(D) The photosensitive resin composition of the above [1] containing an organic solvent.
[3]
The photosensitive resin composition according to [1] or [2], wherein the polymerizable reactive group of the component (B) is an ethylenically unsaturated group or a cyclic ether.
[4]
An optical waveguide including a lower clad layer, a core portion, and an upper clad layer, wherein at least one of the lower clad layer, the core portion, and the upper clad layer is the photosensitive material according to any one of [1] to [3]. An optical waveguide comprising a cured product of a conductive resin composition.
[5]
A method of manufacturing an optical waveguide including a lower clad layer, a core portion, and an upper clad layer, comprising: forming a lower clad layer; forming a core portion; and forming an upper clad layer In addition, at least one of these steps is a photocuring step of irradiating and curing the photosensitive resin composition of any one of [1] to [3], and manufacturing an optical waveguide, Method.
[6]
The method for producing an optical waveguide according to [5], wherein the photocuring step is performed by irradiating light having an illuminance of 0.1 to 30 mW / cm ^{2 at} a wavelength of 254 nm.

An optical waveguide formed by forming at least one of a core portion and a clad layer (particularly, a core portion) using the photosensitive resin composition of the present invention is a waveguide even when transmitting light in the visible light region. There is little loss.
Specific applications of the photosensitive resin composition of the present invention include materials for optical device components (for example, the head of a laser printer) used when transmitting image information by light, and short wavelength lasers (for example, a wavelength of 405 nm). For example, a material of a DVD recording device component (for example, an optical pickup) capable of high-density writing. If light in the visible light region is transmitted in these applications, it is possible to achieve high speed transmission of video information and the like while ensuring transparency.

［式中、Ｒ^１、Ｒ^２、Ｒ^３は各々独立して水素原子または炭素数１〜１２のアルキル基、Ｘはカルボキシル基を有する基、Ｙは重合性反応基を有する基、ＺはＸおよびＹ以外の有機基であり、ｌ、ｎ、ｍは各々、０ではない繰り返し単位数を示す。］
成分（Ａ）の数平均分子量は、好ましくは２，０００〜１００，０００、より好ましくは５，０００〜７０，０００、特に好ましくは１０，０００〜５０，０００である。該値が２，０００未満では、塗布性が悪く、所望の膜厚が得られず、該値が１００，０００を超えると、粘度が高くなり、材料の取り扱いが難しくなる。 The components (A) to (C) and other optional components constituting the photosensitive resin composition of the present invention will be described in detail below.
[Component (A)]
The component (A) used in the present invention is a copolymer having a structure represented by the following general formula (1).

Wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, X is a group having a carboxyl group, Y is a group having a polymerizable reactive group, and Z is X And an organic group other than Y, and each of l, n, and m represents a number of repeating units other than 0. ]
The number average molecular weight of the component (A) is preferably 2,000 to 100,000, more preferably 5,000 to 70,000, particularly preferably 10,000 to 50,000. If the value is less than 2,000, the coating property is poor and a desired film thickness cannot be obtained. If the value exceeds 100,000, the viscosity becomes high and the handling of the material becomes difficult.

Component (A) can be obtained by either of the following two methods (1) and (2). The compound (c) is a radical polymerizable compound other than the compounds (a) and (b).
(1) (a) a radical polymerizable compound having a carboxyl group, (b) a radical polymerizable compound having a polymerizable reactive group (for example, a cyclic ether such as an epoxy group or an oxetanyl group), and (c) other radical polymerization. A radical copolymerization of a functional compound in a solvent.
(2) (a) A radical polymerizable compound having a carboxyl group, and (c) another radical polymerizable compound is radically copolymerized in a solvent to obtain a polymer, and then (d) a reactive functional group ( For example, a method of adding a radically polymerizable compound having an epoxy group) to a part of the carboxyl group of the side chain of the polymer.

The compounds (a) to (d) used in the above methods (1) and (2) will be described.
Examples of the compound (a) (radical polymerizable compound having a carboxyl group) include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid. Acid; Methacrylic acid derivatives having a carboxyl group and an ester bond such as 2-succinoloylethyl methacrylate, 2-malenoloylethyl methacrylate, 2-hexahydrophthaloylethyl methacrylate, and the like.
Among these, acrylic acid, methacrylic acid, and 2-hexahydrophthaloylethyl methacrylate are preferable, and acrylic acid and methacrylic acid are particularly preferable.
A compound (a) is used individually by 1 type or in combination of 2 or more types.
The content of the compound (a) in the component (A) is preferably 5 to 50% by mass, more preferably 10 to 40% by mass. When the content is less than 5% by mass, the composition of the present invention is not easily dissolved when subjected to an alkali development treatment after being cured by light irradiation. For example, it was used as a core portion of an optical waveguide. In this case, the core shape as designed cannot be obtained, and sufficient transmission characteristics cannot be obtained. When the content exceeds 50% by mass, the shape as designed cannot be obtained.

Examples of the compound (b) (radical polymerizable compound having a polymerizable reactive group) include glycidyl (meth) acrylate, α-ethylglycidyl (meth) acrylate, α-n-propylglycidyl (meth) acrylate, α-n. -Butyl glycidyl (meth) acrylate, 2-methyl glycidyl (meth) acrylate, 2-ethyl glycidyl (meth) acrylate, 2-propyl glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4- (Meth) acrylic acid esters having an epoxy group such as epoxy heptyl (meth) acrylate, α-ethyl-6,7-epoxyheptyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate; Ethyl-2-oxetanyl) methyl (meth) a Relate, (2-methyl-2-oxetanyl) methyl (meth) acrylate, 2- (2-ethyl-2-oxetanyl) ethyl (meth) acrylate, 2- (2-methyl-2-oxetanyl) ethyl (meth) acrylate , (Meth) acrylic acid esters having an oxetanyl group such as 3- (2-ethyl-2-oxetanyl) propyl (meth) acrylate and 3- (2-methyl-2-oxetanyl) propyl (meth) acrylate; Vinyl benzyl glycidyl ether, m-vinyl benzyl glycidyl ether, p-vinyl benzyl glycidyl ether, α-methyl-o-vinyl benzyl glycidyl ether, α-methyl-m-vinyl benzyl glycidyl ether, α-methyl-p-vinyl benzyl glycidyl Ether, 2,3-diglycidyl Oxymethylstyrene, 2,4-diglycidyloxymethylstyrene, 2,5-diglycidyloxymethylstyrene, 2,6-diglycidyloxymethylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3, Styrene having an epoxy group such as 5-triglycidyloxymethylstyrene, 2,3,6-triglycidyloxymethylstyrene, 3,4,5-triglycidyloxymethylstyrene, 2,4,6-triglycidyloxymethylstyrene And the like.
Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, p-vinylbenzyl glycidyl ether and the like are preferably used.
A compound (b) is used individually by 1 type or in combination of 2 or more types.
The content rate of the compound (b) in a component (A) becomes like this. Preferably it is 5-50 mass%, More preferably, it is 10-40 mass%. When the content is less than 5% by mass, crosslinking is insufficient and heat resistance and the like are reduced. When the content exceeds 50% by mass, the shrinkage rate at the time of curing increases, and when a cured film is produced on the substrate, the cured film may be peeled off from the substrate due to shrinkage stress.

The compound (c) (other radically polymerizable compound) is mainly used for appropriately controlling the mechanical properties and refractive index of the component (A).
Examples of the compound (c) include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, and t-butyl (meth) acrylate. (Meth) acrylic acid alkyl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate and other (meth) acrylic acid aryl esters; dicarboxylic acid diesters such as diethyl maleate, diethyl fumarate and diethyl itaconate Aromatic resins such as styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-methoxystyrene; conjugated dimers such as 1,3-butadiene, isoprene, 1,4-dimethylbutadiene; Olefin; Acry Nitrile group-containing polymerizable compounds such as nitrile and methacrylonitrile; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; and fatty acid vinyls such as vinyl acetate It is done.
Of these, methyl (meth) acrylate, n-butyl (meth) acrylate, styrene, α-methylstyrene and the like are preferably used.
A compound (c) is used individually by 1 type or in combination of 2 or more types.
The content rate of the compound (c) in a component (A) becomes like this. Preferably it is 5-80 mass%, More preferably, it is 20-70 mass%. When the content is less than 5% by mass, it is difficult to adjust the refractive index. When this content rate exceeds 80 mass%, the solubility to a developing solution will fall and bridge | crosslinking of a cured film will become inadequate.

Examples of the compound (d) (radical polymerizable compound having a reactive functional group) include glycidyl (meth) acrylate, α-ethylglycidyl (meth) acrylate, α-n-propylglycidyl (meth) acrylate, α-n. -Butyl glycidyl (meth) acrylate, 2-methyl glycidyl (meth) acrylate, 2-ethyl glycidyl (meth) acrylate, 2-propyl glycidyl (meth) acrylate, 3,4-epoxybutyl (meth) acrylate, 3,4- (Meth) acrylic acid esters having an epoxy group such as epoxyheptyl (meth) acrylate, α-ethyl-6,7-epoxyheptyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate; o-vinyl Benzyl glycidyl ether, m-vinyl Glycidyl ether, p-vinylbenzyl glycidyl ether, α-methyl-o-vinylbenzyl glycidyl ether, α-methyl-m-vinylbenzyl glycidyl ether, α-methyl-p-vinylbenzyl glycidyl ether, 2,3-di Glycidyloxymethylstyrene, 2,4-diglycidyloxymethylstyrene, 2,5-diglycidyloxymethylstyrene, 2,6-diglycidyloxymethylstyrene, 2,3,4-triglycidyloxymethylstyrene, 2,3 , 5-triglycidyloxymethylstyrene, 2,3,6-triglycidyloxymethylstyrene, 3,4,5-triglycidyloxymethylstyrene, 2,4,6-triglycidyloxymethylstyrene, etc. Examples include styrenes .
Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, p-vinylbenzyl glycidyl ether and the like are preferably used.
A compound (d) is used individually by 1 type or in combination of 2 or more types.
The content rate of the compound (d) in a component (A) becomes like this. Preferably it is 5-50 mass%, More preferably, it is 10-40 mass%. When the content is less than 5% by mass, crosslinking is insufficient and heat resistance and the like are reduced. When the content exceeds 50% by mass, the shrinkage rate at the time of curing increases, and when a cured film is produced on the substrate, the cured film may be peeled off from the substrate due to shrinkage stress.

Examples of the polymerization solvent used for radical copolymerization in the methods (1) and (2) include alcohols such as methanol, ethanol, ethylene glycol, diethylene glycol and propylene glycol; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol monomethyl ether , Ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. Alkyl ethers of alcohols; alkyl ether acetates of polyhydric alcohols such as ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone, methyl isobutyl Ketones such as ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol; ethyl acetate, butyl acetate, ethyl lactate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate Ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methyl Methyl Kishipuropion acid, 3-methoxy ethyl propionate, ethyl 3-ethoxypropionate, esters such as methyl 3-ethoxypropionate and the like.
Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones, and esters are preferred.

In addition, as a polymerization catalyst used for radical copolymerization, a normal radical polymerization initiator can be used, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis- (2,4-dimethylvalero). Nitrile), 2,2′-azobis- (4-methoxy-2′-dimethylvaleronitrile) and the like; benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis- (t- Mention may be made of organic peroxides such as butylperoxy) cyclohexane and hydrogen peroxide. When a peroxide is used as the radical polymerization initiator, a redox initiator may be used in combination with a reducing agent.
As the solvent used for the addition reaction in the method (2), the same solvent as the polymerization solvent used for radical copolymerization can be used. When performing the addition reaction, a thermal polymerization inhibitor can be added to suppress the polymerization reaction due to heat.
Examples of such thermal polymerization inhibitors include pyrogallol, benzoquinone, hydroquinone, methylene blue, tert-butylcatechol, monobenzyl ether, methoxyphenol, amylquinone, amyloxyhydroquinone, n-butylphenol, phenol, hydroquinone monopropyl ether and the like. Can do.
The amount of the thermal polymerization inhibitor used is preferably 5 parts by mass or less with respect to 100 parts by mass of the component (A).

[Component (B)]
Component (B) is a compound having two or more polymerizable reactive groups in the molecule.
Component (B) is a compound that undergoes thermal polymerization and / or photopolymerization, and examples thereof include compounds (1) and (2) shown below.
(1) Compound having two or more ethylenically unsaturated groups in the molecule Examples of the ethylenically unsaturated group include a (meth) acryloyl group and a vinyl group.
Examples of (meth) acrylates having two (meth) acryloyl groups in the molecule include ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4 -Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, bis (hydroxymethyl) ) Tricyclodecane di (meth) acrylate, di (meth) acrylate of diol which is an adduct of bisphenol A ethylene oxide or propylene oxide, hydrogenated bisphenol A ethylene oxide or propylene oxide Di diols are adducts (meth) acrylate, diglycidyl ether (meth) epoxy obtained by adding acrylate (meth) acrylate of bisphenol A, diacrylate of polyoxyalkylenated bisphenol A and the like.
Examples of (meth) acrylate having 3 or more (meth) acryloyl groups in the molecule include compounds in which 3 mol or more of (meth) acrylic acid is ester-bonded to a polyhydric alcohol having 3 or more hydroxyl groups, for example, Trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane trioxyethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate Etc.
In addition, a polyether acrylic oligomer, a polyester acrylic oligomer, a polyurethane acrylic oligomer, or a polyepoxy acrylic oligomer having a polyether, polyester, or polyurethane skeleton in the main chain can also be used.

As these commercial products, Iupimer UV SA1002, SA2007 (above, manufactured by Mitsubishi Chemical Corporation), Biscote # 195, # 230, # 215, # 260, # 295, # 300, # 335HP, # 360, # 400, # 540, # 700, 3PA, GPT (manufactured by Osaka Organic Chemical Industry Co., Ltd.), light acrylate 4EG-A, 9EG-A, NP-A, DCP-A, BP-4EA, BP-4PA, PE-3A, PE -4A, DPE-6A (above, manufactured by Kyoeisha Chemical Co., Ltd.), KAYARAD
MANDA, HX-220, HX-620, R-551, R-712, R-604, R-684, PET-30, GPO-303, TMPTA, DPHA, D-310, D-330, DPCA-20, -30, -60, -120 (Nippon Kayaku Co., Ltd.), Aronix M208, M210, M215, M220, M240, M305, M309, M310, M315, M325, M400, M1200, M6100, M6200, M6250, M7100 M8030, M8060, M8100, M8530, M8560, M9050 (above, manufactured by Toagosei Co., Ltd.), Lipoxy VR-77, VR-60, VR-90 (above, manufactured by Showa Polymer Co., Ltd.), Ebecryl 81, 83, 600, 629 , 645, 745, 754, 767, 701, 755, 70 , 770,800,805,810,830,450,1830,1870 (manufactured by Daicel UCB Co.), Beamset 575,551B, 502H, 102 (Arakawa Chemical Industries, Ltd.).

(2) Compound having two or more cyclic ethers in the molecule As the compound, among oxirane compounds, oxetane compounds, oxolane compounds, etc., compounds having two or more cyclic ethers in the molecule can be used. .
Examples of such oxirane compounds include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy. ) Cyclohexane-meta-dioxane, bis (3,4-epoxycyclohexylmethyl) adipate, vinyl cyclohexylene oxide, 4-vinyl epoxycyclohexane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy -6-methylcyclohexyl-3 ', 4'-epoxy-6'-methylcyclohexanecarboxylate, methylenebis (3,4-epoxycyclohexane), dicyclopentadiene diepoxide, di (3,4-epoxycyclohexyl) of ethylene glycol Methyl) ether, ethylenebis (3,4-epoxycyclohexanecarboxylate), epoxidized tetrabenzyl alcohol, lactone-modified 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, lactone-modified epoxidized tetrahydrobenzyl Alcohol, cyclohexene oxide, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol AD diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether , Epoxy novolac resin, 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 ethers of polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin; diglycidyl aliphatic long-chain dibasic acids Esters; monoglycidyl ethers of higher aliphatic alcohols; phenol, cresol, butylphenol or addition of alkylene oxides to these Monoglycidyl ethers of a polyether alcohol to be; glycidyl esters of higher fatty acids; epoxidized soybean oil, butyl epoxy stearate, epoxy stearic octyl, and the like epoxidized linseed oil.

Oxetane compounds include 3,7-bis (3-oxetanyl) -5-oxa-nonane, 3,3 ′-(1,3- (2-methylenyl) propanediylbis (oxymethylene)) bis- (3- Ethyl oxetane), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1,2-bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [ (3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, dicyclopentenyl bis (3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis ( 3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-oxe) Tanylmethyl) ether, tricyclodecanediyldimethylene (3-ethyl-3-oxetanylmethyl) ether, trimethylolpropane tris (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis (3-ethyl-3- Oxetanylmethoxy) butane, 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, pentaerythritol tris (3-ethyl-3-oxetanylmethyl) ether, pentaerythritol tetrakis (3-ethyl-3-oxetanylmethyl) An ether etc. can be mentioned.
These compounds can be used individually by 1 type or in combination of 2 or more types.

As these commercially available products, Epolite 40E, 100E, 70P, 1500NP, 100MF, 4000, 3002 (manufactured by Kyoeisha Chemical Co., Ltd.), Celoxide 2021, 2081, GT301, GT401, Epolide CDM, PB3600, Epofriend A1005, A1010, A1020 (above, manufactured by Daicel Chemical Industries), Denacol 611, 612, 512, 521, 411, 421, 313, 321 (above, manufactured by Nagase Kasei Co., Ltd.) and the like.
In addition, the component (B) may be a compound having at least one reactive group of an ethylenically unsaturated group and a cyclic ether in the molecule. Examples of such a compound include glycidyl (meth) acrylate, vinylcyclohexene oxide, 4-vinylepoxycyclohexane, 3,4-epoxycyclohexylmethyl (meth) acrylate, and the like.
As the component (B), any one of a compound having two or more ethylenically unsaturated groups in the molecule and a compound having two or more cyclic ethers in the molecule may be used alone, or These may be used in combination.
As the component (B), it is particularly preferable to use a compound having two or more ethylenically unsaturated groups in the molecule.
The compounding amount of the component (B) is preferably 30 to 150 parts by mass, more preferably 50 to 130 parts by mass with respect to 100 parts by mass of the component (A). When the amount is less than 30 parts by mass, the accuracy of the shape of the target waveguide may be inferior when an optical waveguide is formed. When the amount exceeds 150 parts by mass, the phase with the component (A) may be reduced. The solubility may deteriorate, and film roughness may occur on the surface of the cured product.

[Component (C)]
Component (C) is a photopolymerization initiator that can generate an active species capable of polymerizing component (B) by light.
Here, light means, for example, infrared rays, visible rays, ultraviolet rays, and ionizing radiation such as X-rays, electron beams, α rays, β rays, and γ rays.
Component (C) can be broadly classified into those that decompose by light irradiation to generate radicals (photo radical polymerization initiator) and those that generate cations (photo cationic polymerization initiator).
Examples of photo radical polymerization initiators include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole. 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl)- 2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Sandone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, Examples thereof include bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide.
Among them, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one have little light absorption in the visible region, and the obtained optical waveguide has a transmission property (low transmission loss) in the visible region. ), It is preferably used.
Examples of commercially available radical photopolymerization initiators include Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI 11850, CG 24-61, Darocurl 116, 1173 (above, Ciba Specialty Chemicals) Product), Lucirin TPO, TPO-L (above, manufactured by BASF), Ubekrill P36 (manufactured by UCB), and the like.

Examples of the cationic photopolymerization initiator include onium salts having a structure represented by the following general formula (2). This onium salt is a compound that releases a Lewis acid by receiving light.
_{^{[R 4 a R 5 b R}} 6 c R 7 d W] + m [MX n + m] -m (2)
[Wherein the cation is an onium ion, W is S, Se, Te, P, As, Sb, Bi, O, I, Br, Cl or N≡N, and R ⁴ , R ⁵ , R ⁶ and R ⁷ is the same or different organic group, 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 [MX _{n + m} ], for example, B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V , Cr, Mn, Co and the like. X is a halogen atom such as F, Cl, Br, etc., m is the net charge of the halide complex ion, and n is the valence of M. ]
Examples of onium ions in the general formula (2) include diphenyliodonium, 4-methoxydiphenyliodonium, bis (4-methylphenyl) iodonium, bis (4-tert-butylphenyl) iodonium, bis (dodecylphenyl) iodonium, tri Phenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, bis [4- (diphenylsulfonio) -phenyl] sulfide, bis [4- (di (4- (2-hydroxyethyl) phenyl) sulfonio) -phenyl] sulfide , Η ⁵ -2,4- (cyclopentadenyl) [1,2,3,4,5,6-η]-(methylethyl) -benzene] -iron (1+) and the like.
Examples of the anion (MX _{n + m} ) in the general formula (2) include tetrafluoroborate (BF ₄ ⁻ ), hexafluorophosphate (PF ₆ ⁻ ), hexafluoroantimonate (SbF ₆ ⁻ ), hexafluoroarsenate ( AsF ₆ ⁻ ), hexachloroantimonate (SbCl ₆ ⁻ ) and the like.

As another onium salt that can be used as a photocationic polymerization initiator, in the general formula (2), instead of [MX _{n + m} ], the general formula (3):
[MX _n (OH) ⁻ ] (3)
(In the formula, M, X and n are as defined in the general formula (2).)
Anion, perchlorate ion (ClO ₄ ⁻ ), trifluoromethanesulfonate ion (CF ₃ SO ₃ ⁻ ), fluorosulfonate ion (FSO ₃ ⁻ ), toluenesulfonate ion, trinitrobenzenesulfonate ion And onium salts having other anions such as trinitrotoluenesulfonate ion.
Examples of commercially available cationic photopolymerization initiators include UVI-6950, UVI-6970, UVI-6974, UVI-6990 (above Union Carbide), Adekaoptomer SP-150, SP-151, SP-170, SP-171 (above, manufactured by Asahi Denka Kogyo Co., Ltd.), Irgacure
261 (above, manufactured by Ciba Geigy), CI-2481, CI-2624, CI-2639, CI-2064 (above, manufactured by Nippon Soda Co., Ltd.), CD-1010, CD-1011, CD-1012 (above, manufactured by Sartomer) ), DTS-102, DTS-103, NAT-103, NDS-103, TPS-102, TPS-103, MDS-103, MPI-103, BBI-101, BBI-102, BBI-103 (above, Midori Chemical) Degacure)
K126 (manufactured by Degussa) and the like can be mentioned.
A photoinitiator is used individually by 1 type or in combination of 2 or more types.

The content of the component (C) in the photosensitive resin composition of the present invention (the total amount including the later-described component (D) and other optional components) is 0.01 to 0.3% by mass, preferably 0.00. It is 03-0.2 mass%, More preferably, it is 0.05-0.2 mass%, Most preferably, it is 0.1-0.2 mass%. When the proportion is less than 0.01% by mass, curing does not proceed sufficiently, and it is difficult to obtain good shape accuracy and transmission characteristics when manufacturing an optical waveguide. When the ratio exceeds 0.3% by mass, when transmitting light in the visible light region such as blue laser (405 nm), transmission loss of the optical waveguide due to light absorption by the polymerization initiator may occur, or long-term May adversely affect transmission characteristics.
In this invention, it is preferable to mix | blend a photosensitizer with the above-mentioned photoinitiator. If a photosensitizer is used in combination, energy rays such as light can be absorbed more effectively.
Photosensitizers include, for example, thioxanthone, diethylthioxanthone and thioxanthone derivatives; anthraquinone, bromoanthraquinone and anthraquinone derivatives; anthracene, bromoanthracene and anthracene derivatives; perylene and perylene derivatives; xanthone, thioxanthone and thioxanthone derivatives; And ketocoumarin. What is necessary is just to select the kind of photosensitizer according to the kind of photoinitiator.

The photosensitive resin composition of the present invention preferably further contains an organic solvent as component (D). By blending an organic solvent, the storage stability of the photosensitive resin composition can be improved, and an appropriate viscosity can be imparted to form an optical waveguide having a uniform thickness.
The type of the organic solvent can be appropriately selected within a range that does not impair the object and effect of the present invention, but has a boiling point in the range of 50 to 200 ° C. under atmospheric pressure, and each constituent component Those that dissolve uniformly are preferred. Specifically, an organic solvent used when preparing the component (A) can be used.
Preferable examples of the organic solvent include alcohols, ethers, esters, and ketones. Preferable compound names of the organic solvent include at least one solvent selected from the group consisting of propylene glycol monomethyl ether, ethyl lactate, diethylene glycol dimethyl ether, methyl isobutyl ketone, methyl amyl ketone, toluene, xylene, and methanol.
The compounding amount of the organic solvent is preferably 10 to 500 parts by mass with respect to 100 parts by mass of the total amount of the components (A) to (C). When the amount is less than 10 parts by mass, it may be difficult to adjust the viscosity of the photosensitive resin composition. When the amount exceeds 500 parts by mass, it may be difficult to form an optical waveguide having a sufficient thickness.

In the resin composition of the present invention, in addition to the above components (A) to (D), for example, one polymerizable reaction in the molecule, as long as the characteristics of the resin composition of the present invention are not impaired. Group-containing compounds and polymer resins (for example, epoxy resins, acrylic resins, polyamide resins, polyamideimide resins, polyurethane resins, polybutadiene resins, polychloroprene resins, polyether resins, polyester resins, styrene-butadiene block copolymers, Petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine polymer, silicone polymer) and the like can be blended.
Furthermore, various additives as necessary, for example, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, coating surface improvers, thermal polymerization inhibitors, leveling agents, surfactants, colorants, Storage stabilizers, plasticizers, lubricants, fillers, inorganic particles, anti-aging agents, wettability improvers, antistatic agents and the like can be blended.
Here, as the antioxidant, for example, Irganox 1010, 1035, 1076, 1222 (above, manufactured by Ciba Specialty Chemicals), Antigene
Examples thereof include P, 3C, FR, and a smizer (manufactured by Sumitomo Chemical Industries). Examples of ultraviolet absorbers include Tinuvin P, 234, 320, 326, 327, 328, 329, 213 (and above, manufactured by Ciba Specialty Chemicals), Seesorb 102, 103, 110, 501, 202, 712, and 704 (and above). , Manufactured by Sipro Kasei Co., Ltd.). As a light stabilizer, for example, Tinuvin
292, 144, 622LD (above, manufactured by Ciba Specialty Chemicals), Sanol LS770 (manufactured by Sankyo Co., Ltd.), Sumisorb TM-061 (manufactured by Sumitomo Chemical Co., Ltd.), and the like. Examples of the silane coupling agent include γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like, and commercially available products such as SH6062, 6030 (above, Toray Dow Corning Silicone Co., Ltd.), KBE903, 603, 403 (manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of the coating surface improver include silicone additives such as dimethylsiloxane polyether, and commercially available products include DC-57, DC-190 (manufactured by Dow Corning), SH-28PA, SH-29PA, SH. -30PA, SH-190 (above, manufactured by Toray Dow Corning Silicone), KF351, KF352, KF353, KF354 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), L-700, L-7002, L-7500, FK- 024-90 (manufactured by Nihon Unicar).
In order to prepare the photosensitive resin composition of the present invention, the above components may be mixed and stirred according to a conventional method.

Hereinafter, an example of an optical waveguide formed using the photosensitive resin 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 of the present invention 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. Among these three steps, at least one step is a step of forming a cured product by irradiating the above-described photosensitive resin composition with light.
In addition, the photosensitive resin 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, for convenience, a lower layer composition, a core composition, and an upper layer. This is called a composition.
(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 types of photosensitive resin compositions are prepared so that the difference in refractive index is an appropriate magnitude, and among these, the photosensitive resin composition that gives the cured film with the highest refractive index is the core. Other photosensitive resin 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 photosensitive resin composition in terms of economy and production control.
The viscosity of the photosensitive resin composition is preferably 1 to 10,000 mPa · s (25 ° C.), more preferably 5 to 8,000 mPa · s (25 ° C.), particularly preferably 10 to 5,000 mPa · s (25 ° C). When the viscosity is outside this range, it may be difficult to handle the photosensitive resin composition or it may be difficult to form a uniform coating film. In addition, a viscosity can be suitably adjusted by changing compounding quantities, such as an organic solvent.

(2) Preparation of Substrate As shown in FIG. 2A, a substrate 10 having a flat surface is prepared. The type of the substrate 10 is not particularly limited. For example, a silicon substrate 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, a lower layer composition is applied to the surface of the substrate 10 and dried or prebaked to form a 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.
In addition, in order to make the rheological properties of the lower layer composition suitable for the coating method, the lower layer composition requires various leveling agents, thixotropic agents, fillers, organic solvents, surfactants, etc. It is preferable to mix according to this.
Moreover, it is preferable to pre-bake the thin film for lower layers which consists of a composition for lower layers at the temperature of 50-200 degreeC for the purpose of removing an organic solvent etc. after application | coating.
The coating method in the lower clad layer forming step, improvement of rheological characteristics, and the like are the same in the core step forming step and the upper clad layer forming step, which will be described later.

Visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, γ-rays, and the like can be used as the type of light irradiated when forming the lower cladding layer, but particularly ultraviolet light (wavelength: 170 to 300 nm). Is preferred. As the light irradiation device, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, an excimer lamp, an excimer laser, or the like is preferably used.
The amount of light irradiation at the time of forming the lower cladding layer is not particularly limited, but particularly in the present invention, sufficient curing can be achieved even with a small amount of photopolymerization initiator, and the resin composition In order not to cause decomposition or unnecessary crosslinking in the product, light with an illuminance of 0.1 to 30 mW / cm ² , preferably 0.5 to 30 mW / cm ² at a wavelength of 254 nm or 248 nm, is preferably 10 to 5,000 mJ / cm ^2. It is preferable to perform exposure by irradiating so as to be ² . Here, the illuminance at a wavelength of 254 nm indicates a value measured with an illuminometer that combines UIT-150 and UVD-C254 (both manufactured by USHIO INC.).
Moreover, it is preferable to further heat-treat (post-bake) so that the whole coating film may fully harden | cure after exposure. Although this heating condition changes with component compositions of the photosensitive resin composition, etc., it is usually 30 to 400 ° C., preferably 50 to 300 ° C., for example, a heating time of 5 minutes to 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 forming step The amount of light irradiation when forming the core part is not particularly limited, but in the present invention, sufficient curing can be achieved even with a small amount of photopolymerization initiator. Irradiated with light of illuminance of 0.1 to 30 mW / cm ² at a wavelength of 254 nm so as to be 10 to 5,000 mJ / cm ² so as to be realized and not cause decomposition or unnecessary crosslinking in the resin composition. It is preferable to perform exposure.
On the lower clad layer 12, as shown in FIG. 2C, the core composition is applied and dried (and prebaked) to form the core thin film 14. 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, using a heating device such as a hot plate or an oven, for example, at a temperature of 30 to 200 ° C., preferably 50 to 150 ° C. If the post-baking process is performed for 5 to 600 minutes, the core part 20 which is a hardening 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) Forming process of upper clad layer The amount of light irradiation when the upper clad layer is formed is not particularly limited, but a small amount of photopolymerization initiator is sufficient in the present invention. In order to achieve curing and prevent decomposition and unnecessary crosslinking in the resin composition, light having an illuminance of 0.1 to 30 mW / cm ² at a wavelength of 254 nm is set to 10 to 5,000 mJ / cm ^2. It is preferable to irradiate and expose.
An 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.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples, and various embodiments can be modified within the scope of the claims.
[1. Preparation of materials]
The following materials were prepared as components (A) to (C).
(1) Component (A)
Preparation Example 1
After the flask equipped with a dry ice / methanol reflux was purged with nitrogen, 1.3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 53.8 g of ethyl lactate as an organic solvent were charged. Stir until dissolved. Next, 6.7 g of methacrylic acid, 15.7 g of dicyclopentanyl methacrylate, 9.0 g of styrene, and 13.5 g of n-butyl acrylate were charged, and stirring was started gently. Thereafter, the temperature of the solution was raised to 80 ° C., and polymerization was carried out at this temperature for 5 hours. Thereafter, 10.6 g of 3,4-epoxycyclohexylmethyl acrylate, 0.7 g of tetrabutylammonium bromide, and 0.1 g of p-methoxyphenol were added to the obtained solution, and the mixture was stirred at 80 ° C. for 8 hours, whereby a polymer was obtained. An epoxy group was added to a part of the carboxyl group therein to obtain a solution containing a polymer (reaction product) having an acrylic group in the side chain. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After performing this re-dissolution-coagulation operation three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer A-1.

Preparation Example 2
After substituting a flask equipped with a dry ice / methanol reflux with nitrogen, 0.4 g of 2,2′-azobisdimethylvaleronitrile as a polymerization initiator and 59.8 g of ethyl lactate as an organic solvent were dissolved, and the polymerization initiator was dissolved. Stir until Next, 8.0 g of methacrylic acid, 10.0 g of dicyclopentanyl methacrylate, 13.9 g of methyl methacrylate, and 8.0 g of n-butyl acrylate were charged, and stirring was started gently. Thereafter, the temperature of the solution was raised to 70 ° C., and polymerization was carried out at this temperature for 5 hours. Thereafter, 31.9 g of 3,4-epoxycyclohexylmethyl acrylate, 2.2 g of tetrabutylammonium bromide, and 0.1 g of p-methoxyphenol were added to the resulting solution, and the mixture was stirred at 80 ° C. for 8 hours, so that An epoxy group was added to a part of the carboxyl group to obtain a solution containing a polymer (reaction product) having an acrylic group in the side chain. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After this re-dissolution / coagulation operation was performed three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer A-2.

Preparation Example 3
After replacing the flask equipped with a dry ice / methanol reflux with nitrogen, 1.3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 53.8 g of diethylene glycol dimethyl ether as an organic solvent were added. Stir until dissolved. Next, 6.7 g of methacrylic acid, 15.7 g of glycidyl methacrylate, 9.0 g of styrene, and 13.5 g of n-butyl acrylate were charged, and stirring was started gently. Thereafter, the temperature of the solution was raised to 80 ° C., and polymerization was carried out at this temperature for 5 hours. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After this re-dissolution-coagulation operation was performed three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer A-3.

Preparation Example 4
After the flask equipped with a dry ice / methanol reflux was purged with nitrogen, 1.3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 53.8 g of ethyl lactate as an organic solvent were charged. Stir until dissolved. Next, 6.7 g of methacrylic acid, 15.7 g of (2-ethyl-2-oxetanyl) methyl acrylate, 9.0 g of styrene, and 13.5 g of n-butyl acrylate were added, and stirring was started gently. Thereafter, the temperature of the solution was raised to 80 ° C., and polymerization was carried out at this temperature for 5 hours. Thereafter, the reaction product was dropped into a large amount of hexane to solidify the reaction product. Further, it was redissolved in tetrahydrofuran having the same mass as the coagulated product and coagulated again with a large amount of hexane. After this re-dissolution / coagulation operation was carried out three times in total, the obtained coagulated product was vacuum-dried at 40 ° C. for 48 hours to obtain the desired copolymer A-4.

(2) Component (B)
Multifunctional acrylate (M8100, manufactured by Toagosei Co., Ltd.)
Trimethylolpropane triacrylate polyfunctional oxirane compound (trade name “Epolide GT301”, manufactured by Daicel Chemical Industries)
(3) Component (C)
Photoradical polymerization initiator (trade name “Irgcure 184”, manufactured by Ciba Specialty Chemicals)
Photocationic polymerization initiator (trade name “SP170”, manufactured by Asahi Denka Co., Ltd.)
(4) Component (D)
Ethyl lactate Diethylene glycol dimethyl ether [2. Preparation of photosensitive resin composition]
The above-described component (A) (copolymers A-1 to A-4) and components (B) to (D) were uniformly mixed at the blending ratio shown in Table 1, and the photosensitive resin composition J- 1 to J-9 were obtained.

[3. Formation of optical waveguide]
(1) Example 1
(A) Formation of lower clad layer The photosensitive resin composition J-4 was applied on the surface of a silicon substrate with a spin coater, and prebaked using a hot plate at 100 ° C for 10 minutes. Next, the coating film made of the photosensitive resin composition J-4 was irradiated with ultraviolet rays having an illuminance of 1 mW / cm ² at a wavelength of 254 nm for 1,000 seconds (irradiation amount: 1,000 mJ / cm ² ), and photocured. It was. The cured film was post-baked at 150 ° C. for 1 hour to form a lower cladding layer having a thickness of 50 μm.
(B) Formation of core part Next, the photosensitive resin composition J-1 was apply | coated with the spin coater on the lower clad layer, and it prebaked on 100 degreeC and the conditions for 10 minutes using the hotplate. Thereafter, ultraviolet light having an illuminance of 1 mW / cm ^{2 at} a wavelength of 254 nm is applied to the coating film of the photosensitive resin composition J-1 with a thickness of 50 μm through a photomask having a line pattern of 50 μm for 1,000 seconds. The coating film was photocured by irradiation (irradiation amount: 1,000 mJ / cm ² ). Next, the substrate having the photocured coating film was immersed in a developer composed of a 1.0% tetramethylammonium hydroxide aqueous solution (TMAH) to dissolve the unexposed portion of the coating film. Thereafter, post-baking was performed at 150 ° C. for 1 hour to form a core portion having a line pattern having a width of 50 μm.
(C) Formation of upper clad layer Next, the photosensitive resin composition J-4 was applied to the upper surface of the lower clad layer having the core portion with a spin coater, and prebaked at 100 ° C. for 10 minutes using a hot plate. did. Thereafter, the coating film made of the photosensitive resin composition J-4 was irradiated with ultraviolet rays having an illuminance of 1 mW / cm ² at a wavelength of 254 nm for 1,000 seconds to form an upper cladding layer having a thickness of 50 μm.
(2) Examples 2-3 and Comparative Examples 1-3
An optical waveguide was formed in the same manner as in Example 1 except that the photosensitive resin composition shown in Table 2 was used.

[4. Evaluation of optical waveguide]
Optical waveguides (Examples 1 to 3 and Comparative Examples 1 to 3) were evaluated as follows.
(1) Accuracy of shape of optical waveguide The case where the height and width of the core actually formed have dimensions of 50 ± 5 μm with respect to the designed core shape (height 50 μm × line width 50 μm). “○” and “x” in other cases.
(2) Waveguide loss of optical waveguide With respect to the optical waveguide, light having a wavelength of 405 nm was incident from one end. Then, by measuring the amount of light emitted from the other end, the waveguide loss per unit length was determined by the cutback method.
As a result, the case where the waveguide loss was less than 1.0 dB / cm was “◯”, and the case where the waveguide loss was 1.0 dB / cm or more was “x”.
The results are shown in Table 2.

  From Table 2, the optical waveguide (Examples 1 to 3) formed at least partly using the photosensitive resin composition of the present invention is a waveguide even for light in the visible light region (wavelength 405 nm). It can be seen that the loss is small and the shape accuracy is high. On the other hand, optical waveguides (Comparative Examples 1 to 3) consisting only of a photosensitive resin composition not belonging to the present invention have a large waveguide loss and inferior transmission characteristics with respect to light in the visible light region (wavelength 405 nm). I understand.

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 Thin film for core 16 Irradiation light 18 Photomask 20 Core portion 22 Upper clad layer 24 Optical waveguide

Claims (6)

(A) a copolymer having a structure represented by the following general formula (1):

[Wherein R ¹ , R ² and R ³ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, X is a group having a carboxyl group, Y is a group having a polymerizable reactive group, and Z is X And an organic group other than Y, and each of l, n, and m represents a number of repeating units other than 0. ]
(B) a compound having two or more polymerizable reactive groups in the molecule, and (C) a photopolymerization initiator, and the content of the component (C) is 0.01 to 0.3% by mass The photosensitive resin composition characterized by the above-mentioned.   (D) The photosensitive resin composition of Claim 1 containing an organic solvent.   The photosensitive resin composition according to claim 1 or 2, wherein the polymerizable reactive group of the component (B) is an ethylenically unsaturated group or a cyclic ether.   4. An optical waveguide including a lower cladding layer, a core portion, and an upper cladding layer, wherein at least one of the lower cladding layer, the core portion, and the upper cladding layer is according to claim 1. An optical waveguide comprising a cured product of a photosensitive resin composition.   An optical waveguide manufacturing method including a lower clad layer, a core portion, and an upper clad layer, comprising: a step of forming a lower clad layer; a step of forming a core portion; and a step of forming an upper clad layer And at least one of these steps is a photocuring step of irradiating and curing the photosensitive resin composition according to any one of claims 1 to 3 in an optical waveguide, Production method. The method for producing an optical waveguide according to claim 5, wherein the photocuring step is performed by irradiating light having an illuminance of 0.1 to 30 mW / cm ^{2 at} a wavelength of 254 nm.

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