JP4518089B2 - Photosensitive resin composition for optical waveguide, dry film, optical waveguide and method for producing the same - Google Patents

Description

  The present invention relates to a photosensitive resin composition for an optical waveguide, a dry film having a layer made of the photosensitive resin composition, an optical waveguide manufactured using the dry film, and a method for manufacturing the optical waveguide.

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) On the lower clad layer, an inorganic thin film having a higher refractive index is formed, 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 taking a long manufacturing time.

In order to solve such a problem, a method of forming a core portion and a cladding layer using a photosensitive resin composition has been proposed.
For example, after laminating a dry film resist (also referred to as a dry film) composed of a base film and a photosensitive resin layer on a substrate, the dry film is irradiated with a predetermined amount of light to sensitize it. A predetermined portion of the photosensitive resin layer is radiation-cured, and then an unexposed portion of the photosensitive resin layer is removed using a developer such as an aqueous solution of sodium carbonate to produce an optical waveguide including a core layer and a cladding layer. A method is known (Patent Document 1).
According to this method, it is possible to obtain an advantage 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.
On the other hand, radiation curing for optical waveguide formation containing (A) a specific polymer having a carboxyl group, (B) a compound having two or more polymerizable reactive groups in the molecule, and (C) a radiation polymerization initiator. A dry film has been proposed (Patent Document 2).
According to this dry film, optical waveguide photolithography can be performed by development using a dilute alkaline aqueous solution that is superior to organic solvents in terms of environmental safety. Further, according to this dry film, an optical waveguide having high shape accuracy, excellent solvent resistance, and excellent transmission characteristics in a normal atmosphere (room temperature and low humidity) can be produced. .
JP 2000-180643 A JP 2003-195080 A

According to the knowledge found by the present inventors, an optical waveguide formed using a radiation-curable dry film for forming an optical waveguide containing the components (A) to (C) of the above-mentioned document uses a dilute alkaline aqueous solution as a developer. However, there is a problem that the transmission characteristics are deteriorated under high temperature and high humidity, although the shape accuracy is high and the transmission characteristics are excellent in a normal atmosphere (room temperature and low humidity).
The present invention is for an optical waveguide that can be developed with a dilute alkaline aqueous solution at the time of forming a core portion, has high shape accuracy, and can form an optical waveguide having excellent transmission characteristics even under high temperature and high humidity. It aims at providing the dry film which has the layer which consists of a photosensitive resin composition and this photosensitive resin composition.

（式中、Ｒ^１、Ｒ^３及びＲ^４は各々独立して水素原子またはメチル基であり、Ｒ^２はラジカル重合性反応基を含む有機基であり、Ｘ及びＺは各々独立して単結合または２価の有機基であり、Ｙは重合性を有しない有機基を示す。）
（Ｂ）分子内に１個以上のエチレン性不飽和基を有し、分子量が１，０００未満である化合物、及び
（Ｃ）光ラジカル重合開始剤
を含有し、前記（Ｂ）の化合物の配合量が、前記（Ａ）の重合体１００質量部に対して、２０〜１５０質量部であることを特徴とする光導波路用感光性樹脂組成物。 As a result of intensive studies to solve the above problems, the present inventor can develop with a dilute alkaline aqueous solution by using a photosensitive resin composition having a specific component composition, and has high shape accuracy. In addition, the inventors have found that an optical waveguide having excellent transmission characteristics can be formed even under high temperature and high humidity, and completed the present invention.
That is, the present invention provides the following [1] to [8].
[1] (A) The structure represented by the following general formulas (1) to (3) is included, and the proportion of the structure represented by the following general formula (1) is 5 to 40 mol%. 2) a polymer in which the proportion of the structure represented by 30 to 90 mol% and the proportion of the structure represented by the following general formula (3) is 5 to 30 mol%;

(Wherein R ¹ , R ³ and R ⁴ are each independently a hydrogen atom or a methyl group, R ² is an organic group containing a radically polymerizable reactive group, and X and Z are each independently a single bond) Or, it is a divalent organic group, and Y represents an organic group having no polymerizability.)
(B) a compound having one or more ethylenically unsaturated groups in the molecule and having a molecular weight of less than 1,000, and (C) a radical photopolymerization initiator, and blending the compound (B) The amount is 20-150 mass parts with respect to 100 mass parts of polymers of said (A), The photosensitive resin composition for optical waveguides characterized by the above-mentioned.

（式中、Ｒ^１及びＲ^５は各々独立して水素原子またはメチル基であり、Ｘ及びＺは各々独立して、単結合または２価の有機基を示す。）
［３］（Ｄ）分子内に１個以上のエチレン性不飽和基を有し、かつ、ゲルパーミエーションクロマトグラフィーで測定したポリスチレン換算の数平均分子量が１，０００〜１００，０００である、前記（Ａ）の重合体以外の化合物を含有する前記［１］又は［２］に記載の光導波路用感光性樹脂組成物。
［４］（Ｅ）有機溶剤を含有する前記［１］〜［３］のいずれかに記載の光導波路用感光性樹脂組成物。
［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であって、下部クラッド層、コア部分、及び上部クラッド層のうち少なくとも１つが、前記［１］〜［３］のいずれかに記載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。
［６］前記［１］〜［４］のいずれかに記載の感光性樹脂組成物からなる層を有することを特徴とする光導波路用ドライフィルム。
［７］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、コア部分及び上部クラッド層の少なくとも一つが、前記［６］に記載のドライフィルムの感光性樹脂組成物層の硬化物からなり、かつ、前記コア部分の屈折率が前記下部クラッド層と前記上部クラッド層のいずれの屈折率よりも０．１％以上大きいことを特徴とする光導波路。
［８］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［６］に記載のドライフィルムの感光性樹脂組成物層を光照射して硬化させる工程を含むことを特徴とする光導波路の製造方法。 [2] The photosensitive resin composition for an optical waveguide according to [1], wherein the general formula (1) has a structure represented by the following general formula (4).

(In the formula, R ¹ and R ⁵ each independently represent a hydrogen atom or a methyl group, and X and Z each independently represent a single bond or a divalent organic group.)
[3] (D) having one or more ethylenically unsaturated groups in the molecule and having a polystyrene-equivalent number average molecular weight of 1,000 to 100,000 as measured by gel permeation chromatography, The photosensitive resin composition for an optical waveguide according to the above [1] or [2], which contains a compound other than the polymer (A).
[4] The photosensitive resin composition for optical waveguides according to any one of [1] to [3], which contains an organic solvent (E).
[5] 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 the above-described [1] to [3] An optical waveguide comprising a cured product of the photosensitive resin composition according to any one of the above.
[6] A dry film for an optical waveguide, comprising a layer made of the photosensitive resin composition according to any one of [1] to [4].
[7] 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 the dry film according to [6]. An optical waveguide comprising a cured product of a photosensitive resin composition layer, wherein the refractive index of the core portion is at least 0.1% greater than the refractive index of either the lower cladding layer or the upper cladding layer .
[8] A method of manufacturing an optical waveguide including a lower cladding layer, a core portion, and an upper cladding layer, the step of forming a lower cladding layer, the step of forming a core portion, and the formation of an upper cladding layer And at least one of these steps includes a step of irradiating and curing the photosensitive resin composition layer of the dry film according to the above [6]. Method.

According to the photosensitive resin composition of the present invention, when forming the pattern of the optical waveguide, it is possible to develop using a dilute alkaline aqueous solution, and in terms of environmental safety compared to the case of using an organic solvent. Are better.
Moreover, according to the photosensitive resin composition of the present invention, an optical waveguide with high shape accuracy can be formed.
Further, according to the photosensitive resin composition of the present invention, an increase in waveguide loss can be suppressed even under high temperature and high humidity, and an optical waveguide capable of maintaining excellent transmission characteristics can be obtained.
Furthermore, according to the dry film which has the layer which consists of the photosensitive resin composition of this invention, the optical waveguide which has the above-mentioned outstanding characteristic can be formed easily and in a short time with a simple manufacturing process.

（式中、Ｒ^１、Ｒ^３及びＲ^４は各々独立して水素原子またはメチル基であり、Ｒ^２はラジカル重合性反応基を含む有機基であり、Ｘ及びＺは各々独立して単結合または２価の有機基であり、Ｙは重合性を有しない有機基を示す。） The components (A) to (E) and other optional components constituting the photosensitive resin composition for an optical waveguide of the present invention will be described in detail below.
[(A) component]
(A) component used by this invention is a polymer (for example, random copolymer) containing the structure represented by following General formula (1)-(3).

(Wherein R ¹ , R ³ and R ⁴ are each independently a hydrogen atom or a methyl group, R ² is an organic group containing a radically polymerizable reactive group, and X and Z are each independently a single bond) Or, it is a divalent organic group, and Y represents an organic group having no polymerizability.)

（式中、Ｒ^１及びＸは、前記の一般式（１）におけるＲ^１、Ｘと同じであり、Ｒ^５は水素原子又はメチル基であり、Ｚは単結合または２価の有機基である。）
ここで、一般式（４）中のＸ（２価の有機基）の例としては、下記一般式（５）で表される構造や、フェニレン基等が挙げられる。

（式中、Ｒ^６はメチレンまたは炭素数２〜８のアルキレン基である。）
一般式（４）中のＺ（２価の有機基）の例としては、−（ＣＨ_２）_ｎ−Ｏ−（式中、ｎは１〜８の整数である。）等が挙げられる。 Preferable examples of the structure represented by the general formula (1) include a structure represented by the following general formula (4).

(Wherein, R ¹ and X are the same as R ^1, X in the general formula (1), R ⁵ is a hydrogen atom or a methyl group, Z is a single bond or a divalent organic group .)
Here, examples of X (divalent organic group) in the general formula (4) include a structure represented by the following general formula (5) and a phenylene group.

(In the formula, R ⁶ is methylene or an alkylene group having 2 to 8 carbon atoms.)
Examples of Z (divalent organic group) in the general formula (4) include — (CH ₂ ) _n —O— (wherein n is an integer of 1 to 8).

（式中、Ｒ^７は炭素数１〜２０の直鎖状、分岐状または環状の炭素鎖を有する基である。） Examples of Y in the general formula (2) include a structure represented by the following general formula (6), a phenyl group, a cyclic amide group, a pyridyl group, and the like.

(In the formula, R ⁷ is a group having a linear, branched or cyclic carbon chain having 1 to 20 carbon atoms.)

Examples of Z in formula (3) include a single bond, —R ¹ —O—C (═O) —R ² — (wherein R ¹ and R ² are each independently methylene, or An alkylene group having 2 to 4 carbon atoms).
(A) The ratio of the structure represented by General formula (1) in a component (polymer) is 5-40 mol%, Preferably it is 10-35 mol%.
When the proportion is less than 5 mol%, the composition tends to be insufficiently cured. When this content rate exceeds 40 mol%, it may become difficult to adjust the refractive index of the hardened | cured material of a composition.
(A) The ratio of the structure represented by General formula (2) in a component (polymer) is 30-90 mol%, Preferably it is 40-82 mol%.
When the proportion is less than 30 mol%, it may be difficult to adjust the refractive index of the cured product of the composition. When the proportion exceeds 90 mol%, the composition tends to be insufficiently cured.
(A) The ratio of the structure represented by General formula (3) in a component (polymer) is 5-30 mol%, Preferably it is 8-25 mol%.
If the proportion is less than 5 mol%, it becomes difficult to dissolve when the composition is photocured and subjected to an alkali development treatment, so when the core portion of the optical waveguide is formed, the core shape as designed cannot be obtained, It is difficult to obtain sufficient transmission characteristics. When the proportion exceeds 30 mol%, it is difficult to obtain a product having a shape as designed.

The polystyrene-equivalent weight average molecular weight of the component (A) is preferably 5,000 to 100,000, more preferably 8,000 to 70,000, and particularly preferably 10,000 to 50,000. When the value is less than 5,000, the composition has a low viscosity, and a desired film thickness cannot be obtained. When the value exceeds 100,000, the composition has a high viscosity, and the coating is applied. There are drawbacks such as worsening of properties.
Examples of the method for producing the component (A) include: (a) a radical polymerizable compound having a hydroxyl group; (c) a component (radical polymerizable compound corresponding to the general formula (2)); and (d) a carboxyl group. The radically polymerizable compound (radical polymerizable compound corresponding to the general formula (3)) is radically polymerized in a solvent, and then (b) (meth) acryloyloxy is added to the side chain hydroxyl group of the component (a). The method of adding the isocyanate which has group is mentioned.
The compounds (a) to (d) used in this method will be described.

The compound (a) (radical polymerizable compound having a hydroxyl group) reacts with a hydroxyl group in the compound (a) and an isocyanate group (—N═C═O) in the compound (b) to form a urethane bond (— NH-COO-) and a compound having a side chain moiety that includes a (from b) (meth) acryloyloxy group (the general formula (4) corresponding to ^{"-O-CO-CR 5 = CH} 2 " in) Used to introduce the structural unit into component (A).
Examples of the compound (a) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxymethyl (meth) acrylate, and 4-hydroxycyclohexyl (meth). An acrylate etc. are mentioned.
A compound (a) is used individually by 1 type or in combination of 2 or more types.

  Examples of the compound (b) (isocyanate having a (meth) acryloyloxy group) include 2-methacryloxyethyl isocyanate, N-methacryloyl isocyanate, methacryloxymethyl isocyanate, 2-acryloxyethyl isocyanate, N-acryloyl isocyanate, acryl Examples include loxymethyl isocyanate.

The compound (c) (compound corresponding to the structure of the general formula (2)) 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: dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, 8-((meth) acryloyloxy) tricyclo [5.2.1.0 ^2,6 ] decane, etc. Of (meth) acrylic acid and cyclic hydrocarbon compound: phenyl (meth) acrylate, benzyl (meth) acrylate, o-phenylphenol glycidyl ether (meth) acrylate, 4- (1-methyl-1-phenylethyl) ) Phenoxyethyl acrylate (notation: p (Meth) allylic acid aryl esters such as cumylphenoxyethylene glycol acrylate); tribromophenol ethoxy (meth) acrylate, 2,2,2-trifluoromethyl (meth) acrylate, 2,2,3,3-tetra Halogenated (meth) acrylic esters such as fluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate; styrene, α-methylstyrene, m- Aromatic vinyls such as methylstyrene, p-methylstyrene, vinyltoluene and p-methoxystyrene; conjugated diolefins such as 1,3-butadiene, isoprene and 1,4-dimethylbutadiene; acrylonitrile, methacrylonitrile, etc. Nitrile group-containing weight Sexual compounds; acrylamide, amide bond-containing polymerizable compounds such as methacrylamide, fatty acid vinyl such as vinyl acetate and the like.
Among them, dicyclopentanyl (meth) acrylate, methyl (meth) acrylate, n-butyl (meth) acrylate, 8-((meth) acryloyloxy) tricyclo [5.2.1.0 ^2,6 ] decane, 4 -(1-Methyl-1-phenylethyl) phenoxyethyl acrylate (another notation: p-cumylphenoxyethylene glycol 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.

Examples of the compound (d) (radical polymerizable compound having a carboxyl group) include monocarboxylic acids such as acrylic acid and methacrylic acid; 2-succinoloylethyl methacrylate, 2-malenoylethyl methacrylate, 2-hexahydrophthalo A methacrylic acid derivative having a carboxyl group and an ester bond such as ylethyl methacrylate can be used.
Among these, acrylic acid, methacrylic acid, and 2-hexahydrophthaloylethyl methacrylate are preferable, and acrylic acid and methacrylic acid are more preferable.
These compounds can be used alone or in combination of two or more.
In addition, the compounding ratio of the compounds (a) to (d) is such that each structure represented by the general formula (1), the general formula (2), and the general formula (3) constituting the component (A) has the above-described ratio ( Mol%).

In the process of producing the component (A), various additives such as a thermal polymerization inhibitor, a storage stabilizer, and a curing catalyst can be added during the addition reaction of the compound (b).
The thermal polymerization inhibitor is blended in order to suppress a polymerization reaction due to heat. Examples of 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.
Examples of the storage stabilizer include 2,6-di-t-butyl-p-cresol, benzoquinone, p-toluquinone, p-xyloquinone, phenyl-α-naphthylamine and the like.
Examples of the curing catalyst include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioleate, dibutyltin diacetate, tetramethoxytitanium, tetraethoxytitanium and the like.
The total compounding amount of these various additives is usually 10 parts by mass or less, preferably 5 parts by mass or less with respect to 100 parts by mass of the total amount of the compounds (a) to (d).

In the production of component (A), an isocyanate adduct of compound (a) (a compound corresponding to the structure of general formula (1)), compound (c) (a compound corresponding to the structure of general formula (2)), Examples of the solvent that can be used for radical polymerization with the compound (d) (compound corresponding to the structure of the general formula (3)) include alcohols such as methanol, ethanol, ethylene glycol, diethylene glycol, and propylene glycol; tetrahydrofuran, dioxane, and the like. Cyclic ethers; 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 Alkyl ethers of polyhydric alcohols such as ter, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether; ethylene glycol ethyl ether acetate, diethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol Alkyl ether acetates of polyhydric alcohols such as monomethyl ether acetate; aromatic hydrocarbons such as toluene and xylene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol Ketones such as ethyl acetate, butyl acetate, ethyl lactate, -Ethyl hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxypropion Examples include esters such as methyl acid, ethyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and methyl 3-ethoxypropionate.
Of these, cyclic ethers, polyhydric alcohol alkyl ethers, polyhydric alcohol alkyl ether acetates, ketones, and esters are preferred.
On the other hand, when a solvent having a hydroxyl group in the molecule is used as the solvent used in the addition reaction of the compound (b) at the formation of the structure of the general formula (1) in the production of the component (A), the compound (b) Is not preferable because it reacts with the solvent. Therefore, the solvent used for the addition reaction of the compound (b) is preferably one having no hydroxyl group. Examples of the solvent having no hydroxyl group include those having no hydroxyl group among the solvents used for the radical polymerization.

  Moreover, a normal radical polymerization initiator can be used as a catalyst for radical polymerization used for manufacture of (A) component. Examples of radical polymerization initiators include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2, Azo compounds such as 4-dimethylvaleronitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, t-butylperoxypivalate, 1,1′-bis (t-butylperoxy) cyclohexane; and hydrogen peroxide Can be mentioned. When a peroxide is used as the radical polymerization initiator, a redox initiator may be used in combination with a reducing agent.

  When using the photosensitive resin composition of this invention as the photosensitive resin composition layer of a dry film, the glass transition temperature of (A) component needs to be 20-150 degreeC. At this time, the glass transition temperature is normally defined using a differential scanning calorimeter (DSC). When the glass transition temperature of component (A) is less than 20 ° C., it becomes difficult to form a photosensitive resin composition layer on the base film, or stickiness occurs, and transfer (lamination) occurs. Cause inconvenience. On the other hand, if the temperature exceeds 150 ° C., the photosensitive resin composition layer may become hard or brittle, and transfer may not be possible.

[Component (B)]
Component (B) is a compound having one or more ethylenically unsaturated groups in the molecule and a molecular weight of less than 1,000.
Here, examples of the ethylenically unsaturated group include a (meth) acryloyl group and a vinyl group.
Preferable examples of the component (B) having one ethylenically unsaturated group in the molecule include (meth) acrylates having one (meth) acryloyl group in the molecule.
Moreover, as a preferable example of (B) component which has a 2 or more ethylenically unsaturated group in a molecule | numerator, the compound which has a 2 or more (meth) acryloyl group and / or a vinyl group in a molecule | numerator is mentioned. In this case, all of the ethylenically unsaturated groups in the molecule may be any one of acryloyl group, methacryloyl group, and vinyl group, or acryloyl group and methacryloyl group, acryloyl group and vinyl group, and methacryloyl group. And a combination of any two of vinyl group, or a combination of three types of acryloyl group, methacryloyl group and vinyl group.
Particularly preferred examples of the component (B) having two or more ethylenically unsaturated groups in the molecule include compounds having two or more (meth) acryloyl groups in the molecule.
Component (B) has a molecular weight of less than 1,000. Moreover, it is preferable that the boiling point in 0.1 MPa of (B) component is 130 degreeC or more.

  Examples of (meth) acrylates having one (meth) acryloyl group in the molecule include dimethylaminoethyl (meth) acrylate, acryloylmorpholine, dimethylacrylamide, diethylacrylamide, diisopropylacrylamide, diacetoneacrylamide, isobutoxy Methyl (meth) acrylamide, N-vinylpyrrolidone, N-vinylcaprolactam, isobornyl (meth) acrylate, dicyclopentenyl acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 3-hydroxy- 1-adamantyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate Rate, cyclohexyl (meth) acrylate, isoamyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, tricyclo Decanyl (meth) acrylate, 2-acryloylcyclohexyl succinic acid, tetrahydrofurfuryl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, butoxyethyl (meth) acrylate, alkyl alcohol (1-8 carbon atoms) ) (Meth) acrylate of an alcohol which is an adduct of ethylene oxide, (meth) acrylate of an alcohol which is an adduct of an ethylene oxide of phenol, p-cumylphenol (Meth) acrylate of alcohol which is an adduct of ethylene oxide, (meth) acrylate of alcohol which is an adduct of ethylene oxide of nonylphenol, o-phenylphenol glycidyl ether (meth) acrylate, 2-hydroxyethyl (meth) acrylate , 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-phenoxyethyl (Meth) acrylate, ethyl carbitol (meth) acrylate, 2-ethylhexyl (meth) acrylate, 3-hydroxycyclohexyl acrylate, tribromophenol ethoxy (meth) a Chlorate, 2,2,2-trifluoromethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (meth) acrylate, perfluorooctylethyl Examples include (meth) acrylate.

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 (meth) acrylate of diol as additive, epoxy (meth) acrylate obtained by adding (meth) acrylate to diglycidyl ether of bisphenol A, diacrylate of polyoxyalkylenated bisphenol A, 9,9-bis [4 -(2-acryloyloxyethoxy) phenyl] fluorene and the like.
Examples of (meth) acrylates 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.
Moreover, polyether acrylic oligomer, polyester acrylic oligomer, or polyepoxy acrylic oligomer having polyether or polyester in the main chain can also be used.

As these commercial products, Iupimer UV SA1002, SA2007 (above, manufactured by Mitsubishi Chemical Corporation), Biscote # 150, # 155, # 160, # 190, # 192, # 195, # 230, # 215, # 260, # 260 295, # 300, # 335HP, # 360, # 400, # 540, # 700, 3F, 3FM, 4F, 8F, 8FM, 2-MTA, 2-ETA, V-MTG, 3PA, GPT, HEA, HPA, 4-HBA, AIB, IOAA, LA, STA (manufactured by Osaka Organic Chemical Industry Co., Ltd.), light ester M, E, NB, IB, EH, ID, L, L-7, TD, L-8, S , 130MA, 041MA, CH, THF, BZ, PO, IB-X, HO, HOP, HOA, HOP-A, HOB, DM, DE, HO-MS, EG, 2EG, 1.4BG, 1.6HX, 1.9ND, 1.10DC, TMP, G-101P, G-201P, BP-2EM, BP-4EM, BP-6EM, MTG, BO, BC, 3EG, 4EG, 9EG, 14EG, NP, FM-108, G-201P, light acrylate IO-A, HOB-A, TMP-3EO-A, FA-108, IAA, LA, SA, BO-A, EC-A, MTG-A, 130A, DPM-A, PO-A, P-200A, NP-4EA, NP-8EA, THF-A, IB-XA, HOA, HOP-A, M-600A, HOA-MS, 3EG-A, 4EG- A, 9EG-A, 14EG-A, NP-A, MPD-A, 1.6HX-A, BEPG-A, 1.9ND-A, MOD-A, DCP-A, BP-4EA, BP-4PA, BP-10EA, MP-A, TMP-6EO-3A, PE-3A, PE-4A, DPE-6A, BA-104, BA-134 (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 (above, 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.), NK ester # 401P, K ester A-BPEF, NK ester A-CMP-1E (above, Shin-Nakamura Chemical Co., Ltd.), New Frontier BR-31 (above, Daiichi Kogyo Seiyaku Co., Ltd.), Lipoxy VR-77, VR-60, VR -90 (above, Showa Polymer Co., Ltd.), Ebecryl 81, 83, 600, 629, 645, 745, 754, 767, 701, 755, 705, 770, 800, 805, 810, 830, 450, 1830, 1870 ( As described above, Daicel UCB), beam sets 575, 551B, 502H, 102 (above, Arakawa Chemical Co., Ltd.), adamantate HA, HM (above, Idemitsu Kosan Co., Ltd.) and the like can be mentioned.
(B) A component is used individually by 1 type or in combination of 2 or more types.
(B) The compounding quantity of a component is 20-150 mass parts with respect to 100 mass parts of (A) component. When the amount is less than 5 parts by mass, the accuracy of the shape of the target waveguide may be inferior when forming an optical waveguide. 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 photo radical polymerization initiator capable of generating an active species (radical species) capable of polymerizing an ethylenically unsaturated group by light irradiation.
Here, light means ionizing radiation such as infrared rays, visible rays, ultraviolet rays, and X-rays, electron beams, α rays, β rays, and γ rays.
Examples of the photo radical polymerization initiator 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 Xanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, And bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide.
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, Darocur 1116, 1173 (and above, Ciba Specialty Chemicals). Co., Ltd.), Lucirin TPO, TPO-L (above, manufactured by BASF), Ubekrill P36 (manufactured by UCB), and the like.
A radical photopolymerization initiator is used individually by 1 type or in combination of 2 or more types.

The content rate of (C) component in the photosensitive resin composition of this invention becomes like this. Preferably it is 0.1-10 mass%, More preferably, it is 0.5-5 mass%. When the content is less than 0.1% by mass, curing does not proceed sufficiently, and a problem may occur in the transmission characteristics of the optical waveguide. On the other hand, when the content exceeds 10% by mass, the radical photopolymerization initiator may adversely affect long-term transmission characteristics.
In this invention, a photosensitizer can be mix | blended with the above-mentioned radical photopolymerization initiator. 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.

(D) component can be used for the photosensitive resin composition of this invention. The component (D) has two or more ethylenically unsaturated groups in the molecule, and has a polystyrene-reduced number average molecular weight of 1,000 to 100,000 as measured by gel permeation chromatography. ) A compound other than the component.
Here, examples of the ethylenically unsaturated group include a (meth) acryloyl group and a vinyl group.
(D) As a component, both terminal (meth) acryl modified polyethylene glycol, both terminal (meth) acryl modified polypropylene glycol, etc. are mentioned, for example. At this time, the (meth) acryl groups at both ends may be directly bonded to the polyalkylene chain, or may be bonded via another organic group. Moreover, organic groups other than polyalkylene may be included in the middle of the polyalkylene chain.
As a method for producing such a compound,
Production method 1: A method of esterifying polyalkylene glycol such as polyethylene glycol or polypropylene glycol and (meth) acrylic acid by dehydration condensation,
Production method 2: A method of reacting a polyol compound and a polyisocyanate compound and then reacting a hydroxyl group-containing (meth) acrylate,
Production method 3: A method in which a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate are reacted, and then a polyol compound is reacted,
Production Method 4: A method of reacting a polyisocyanate compound and a hydroxyl group-containing (meth) acrylate, then reacting a polyol compound, and finally reacting a hydroxyl group-containing (meth) acrylate again,
Etc.
The number average molecular weight in terms of polystyrene measured by gel permeation chromatography of component (D) is 1,000 to 100,000.
The content rate of (D) component in the photosensitive resin composition of this invention becomes like this. Preferably it is 0-30 mass%, More preferably, it is 0-25 mass%. If the content exceeds 30% by mass, the transmission characteristics may deteriorate under high temperature and high humidity.

The photosensitive resin composition of the present invention preferably further contains an organic solvent as the component (E). 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, the organic solvent used when preparing (A) component can be used.
Preferable examples of the organic solvent include alcohols, ethers, esters, and ketones. Preferred organic solvent compound names include at least selected from the group consisting of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, diethylene glycol dimethyl ether, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, toluene, xylene, and methanol. One solvent is mentioned.
The content of the component (E) (organic solvent) in the photosensitive resin composition of the present invention is preferably 5 to 80% by mass, more preferably 10 to 60% by mass, and particularly preferably 15 to 55% by mass. .
When the content is less than 5% by mass, it may be difficult to adjust the viscosity of the photosensitive resin composition. If the amount exceeds 80% by mass, it may be difficult to form an optical waveguide having a sufficient thickness.

In the resin composition of the present invention, if necessary, in addition to the above components (A) to (E), for example, one polymerizable group in the molecule, as long as the characteristics of the resin composition of the present invention are not impaired. A compound having a reactive group or a polymer resin (for example, epoxy resin, acrylic resin, polyamide resin, polyamideimide resin, polyurethane resin, polybutadiene resin, polychloroprene resin, polyether resin, polyester resin, styrene-butadiene block copolymer) Petroleum resin, xylene resin, ketone resin, cellulose resin, fluoropolymer, silicone polymer) and the like.
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, examples of the antioxidant include Irganox 1010, 1035, 1076, 1222 (manufactured by Ciba Specialty Chemicals Co., Ltd.), Antigene P, 3C, FR, and Sumilizer (manufactured by Sumitomo Chemical Co., Ltd.). 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.). Examples of the light stabilizer include Tinuvin 292, 144, 622LD (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 and SZ6030 (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).
The photosensitive resin composition of the present invention can be obtained by mixing and stirring the above components according to a conventional method.

Next, the dry film for optical waveguides of the present invention will be described in detail.
The dry film for optical waveguides of the present invention has the above-mentioned uncured photosensitive resin composition layer (not liquid; for example, dried product).
In the present specification, the term “dry film” is defined as having at least an uncured photosensitive resin composition layer and a base film for supporting the layer.
The dry film of the present invention comprises (a) a laminate of a base film and an uncured photosensitive resin composition layer for the lower cladding layer, (b) a base film, and a lower cladding layer (of the photosensitive resin composition). A layered body of a cured body) and an uncured photosensitive resin composition layer for the core portion, and (c) a layered body of a base film and an uncured photosensitive resin composition layer for the core portion. , (D) a laminate of a base film and an uncured photosensitive resin composition layer for the upper clad layer, (e) the laminate of any one of (a) to (d), Each form of a laminate formed by laminating a cover film on the photosensitive resin composition layer is included.
Here, the cover film is a member for protecting the uncured photosensitive resin composition, and is peeled off when the dry film is used. A cover film is a member arbitrarily provided as needed. Therefore, the dry film can comprise an uncured photosensitive resin composition layer as an exposed surface as in the above-described forms (a) to (d).
In this specification, the base film for supporting the uncured photosensitive resin composition layer for the lower cladding layer is referred to as a “base film for the lower layer”, and the uncured photosensitive resin for the upper cladding layer. The base film for supporting the composition layer is referred to as “upper layer base film”, and the base film for supporting the uncured photosensitive resin composition layer for the core portion is referred to as “core base film”. Called.

As a method for forming a photosensitive composition layer on a base film, a photosensitive resin composition is formed by spin coating, dipping, spraying, bar coating, roll coating, curtain coating, gravure printing, silk, Examples thereof include a method in which a solvent is scattered using a dryer or the like after coating on a base film using a method such as a screen method or an ink jet method. The temperature condition for scattering the organic solvent is preferably 30 to 150 ° C, more preferably 50 to 140 ° C.
The amount of the organic solvent remaining after drying is preferably 20 parts by mass or less based on 100 parts by mass of the photosensitive resin composition after the organic solvent is dispersed. Moreover, the thickness of the photosensitive resin composition layer is usually 1 to 200 μm.
Examples of the base film include a polyethylene terephthalate film. Although the thickness of a base film is not specifically limited, For example, it is 10-200 micrometers.
Examples of the cover film include a polyethylene film, a polypropylene film, and a polyethylene terephthalate film. Although the thickness of a cover film is not specifically limited, For example, it is 5-100 micrometers.

Hereinafter, an example of the dry film manufactured using the photosensitive resin composition of the present invention, an optical waveguide, and an optical waveguide manufacturing method 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 film 1 is a film including a structure of an optical waveguide (consisting of a lower clad layer, a core portion and an upper clad layer), and is formed on the upper surface of the lower layer base film 2 and the lower layer base film 2. The formed lower clad layer 3, the core portion 4 having a specific width formed on the upper surface of the lower clad layer 3, and the upper clad layer formed by being laminated on the core portion 4 and the lower clad layer 3 5 and an upper layer base film 6 laminated on the upper surface of the upper clad layer 5. The core portion 4 is embedded in the lower cladding layer 3 and the upper cladding layer 5. FIG. 1 shows a part of the optical waveguide film 1.
The thicknesses of the lower cladding layer 3, the core portion 4, and the upper cladding layer 5 in the optical waveguide are not particularly limited. For example, the thickness of the lower cladding layer 3 is 1 to 200 μm, and the thickness of the core portion 4 is 3 to 3. The thickness is determined to be 200 μm and the thickness of the upper cladding layer 5 is 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 4 needs to be higher than any of the refractive indexes of the lower cladding layer 3 and the upper cladding layer 5. For example, for light having a wavelength of 400 to 1,600 nm, the refractive index of the core portion 4 is 1.420 to 1.650, and the refractive indexes of the lower cladding layer 3 and the upper cladding layer 5 are 1.400 to 1.648. In addition, it is preferable that the refractive index of the core portion 4 is at least 0.1% larger than the refractive indexes of the two cladding layers 3 and 5.
In the present invention, at least one of the lower clad layer 3, the core portion 4 and the upper clad layer 5 is a cured product obtained by light irradiation of the photosensitive resin composition having the specific component composition.
In a preferred embodiment of the present invention, the lower clad layer 3, the core portion 4 and the upper clad layer 5 are all cured products obtained by light irradiation of the photosensitive resin composition having the specific component composition. It is.
In the present invention, at least one of the lower clad layer 3, the core portion 4, and the upper clad layer 5 is formed using a dry film having the uncured photosensitive resin composition layer (for example, dried product). It is preferable.
In addition, the photosensitive resin composition prepared in order to form each part of the lower clad layer 3, the core part 4, and the upper clad layer 5 is, for convenience, a lower layer composition, a core composition, and an upper layer composition, respectively. It is called a thing. Moreover, the dry film which has the photosensitive resin composition layer formed from the composition for lower layers, the composition for cores, and the composition for upper layers, respectively, the dry film for lower layers, the dry film for cores, and the dry film for upper layers Called.

Each component composition of the lower layer composition, the core composition, and the upper layer composition requires the optical waveguide to have a refractive index relationship between the lower cladding layer 3, the core portion 4, and the upper cladding layer 5. It is determined to satisfy the conditions. Specifically, two or three types of photosensitive resin compositions having an appropriate difference in refractive index are prepared, and among these, a photosensitive resin composition that gives a cured film having the highest refractive index is prepared. The composition for the core is used, and another photosensitive resin composition is used as the composition for the lower layer and the composition for the upper layer.
The lower layer composition and the upper layer composition are preferably the same photosensitive resin composition in terms of economy and production control.
At least one of the composition for the lower layer, the composition for the core, and the composition for the upper layer is preferably applied on the base film by the method described above and used as a dry film. That is, in the present invention, (a) a method in which only the core portion is formed using a dry film, and a lower cladding layer and an upper cladding layer are formed using a liquid photosensitive resin composition, (b) a lower cladding layer and A method of forming a core portion using a dry film and forming an upper clad layer using a liquid photosensitive resin composition; and (c) forming a lower clad layer, a core portion, and an upper clad layer using a dry film. A method, (d) a method in which the lower clad layer and the upper clad layer are formed using a dry film, and a core portion is formed using a liquid photosensitive resin composition can be employed.
FIG. 2 shows the method (d).

[2. Manufacturing method of optical waveguide]
In FIG. 2, the manufacturing method of the optical waveguide film 1 of the present invention includes a step of forming the lower cladding layer 3 ((a) to (c) in FIG. 2) and a step of forming the core portion 4 (in FIG. 2). (D) to (f)) and the step of forming the upper cladding layer 5 ((g) to (j) in FIG. 2).
(1) Formation process of lower clad layer This is a process of forming the lower clad layer 3 on the upper surface of the base film 2. Specifically, first, a liquid photosensitive resin composition for a lower layer is applied to the upper surface of the base film 2 by spin coating, dipping, spraying, bar coating, roll coating, curtain coating, and gravure printing. The dry film 11 having an uncured lower layer photosensitive resin composition layer (photosensitive layer) 10 is obtained by applying using any method such as a silk screen method or an ink jet method, followed by drying or prebaking (FIG. 2 (a), (b)).
Next, the photosensitive layer 10 of the dry film 11 is irradiated with light and cured to form the lower cladding layer 3 ((c) in FIG. 2). After the light irradiation, it is preferable to further post-bake the lower cladding layer 3 as necessary.
The photosensitive layer 10 of the dry film 11 may be pre-baked at a temperature of 50 to 200 ° C. for the purpose of removing the remaining solvent, if necessary.
The amount of light irradiation when forming the lower cladding layer is not particularly limited, but light with a wavelength of 200 to 450 nm and an illuminance of 1 to 500 mW / cm ² is applied with an irradiation amount of 10 to 5,000 mJ / cm 2. It is preferable to perform exposure by irradiating so as to be ² .
Visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, and γ rays can be used as the type of light to be irradiated, and ultraviolet rays are particularly preferable. As the light irradiation device, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, an excimer lamp, or the like is preferably used. In the step of forming the lower clad layer, it is preferable to irradiate the entire surface of the photosensitive layer 10 with light and harden the whole.
Further, after the exposure, it is preferable to perform a heat treatment (post-bake) so that the entire surface of the lower cladding layer 3 is sufficiently cured. The heating conditions vary depending on the composition of the photosensitive resin composition, the type of additive, and the like. Usually, the heating temperature is 30 to 300 ° C., preferably 50 to 200 ° C., and the heating time is 5 minutes to 72 hours. It is.
The light irradiation amount, type, and light 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 portion forming step The core photosensitive resin composition 13 is applied to the upper surface of the lower clad 3 and dried or prebaked, so that an uncured layer (photosensitive layer) 13 of the core photosensitive resin composition is formed. Is formed ((d) of FIG. 2). The method of application is the same as that of the above-described photosensitive resin composition for the lower layer. Since the obtained laminate has the base film 2 and the uncured photosensitive layer 13, it is a dry film 14.
The photosensitive layer 13 may be formed using a core dry film. In this case, a dry film for the core is used in which a base film, an uncured layer (photosensitive layer) 13 of the core photosensitive resin composition, and a cover film for protecting the photosensitive layer 13 are laminated. . In order to form the photosensitive layer 13 on the upper surface of the lower cladding 3, first, the cover film is peeled off to obtain a laminate of the base film and the photosensitive layer 13, and this laminate is then placed on the photosensitive layer 13 side. May be transferred (laminated) to the upper surface of the lower cladding layer 3, and then the base film may be peeled from the photosensitive layer 13.
After the formation of the photosensitive layer 13, the upper surface of the photosensitive layer 13 is irradiated with light 16 according to a predetermined pattern, for example, through a photomask 15 having a predetermined line pattern ((e) in FIG. 2). Thereby, in the photosensitive layer 13, only the part irradiated with light hardens | cures, and other parts remain uncured. Thereafter, the uncured portion is removed by development processing, whereby the core portion 4 made of a patterned cured film can be formed on the upper surface of the lower cladding layer 3 ((f) in FIG. 2).

As described above, the method of irradiating light according to a predetermined pattern is not limited to a method using a photomask including a light transmitting portion and a non-transmitting portion, and examples thereof include the following methods a to c.
a. A method using electro-optical means for forming a mask image composed of a light transmitting region and a light non-transmitting region according to 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 laser light or convergent light obtained by a condensing optical system such as a lens or a mirror while scanning.

The thin film that has been pattern-exposed and selectively cured in this manner according to a predetermined pattern can be developed using the difference in solubility between the cured portion and the uncured portion. Therefore, after pattern exposure, while removing an uncured part and leaving a cured part, a core part can be formed as a result.
As the developer, an ordinary organic solvent used in the development process can be used. However, the photosensitive resin composition of the present invention can be developed with a dilute alkaline aqueous solution that is superior in terms of environmental safety. It is preferable to use a dilute alkaline aqueous solution. Examples of alkali compounds for preparing dilute aqueous alkali solutions include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propyl. Amine, triethylamine, methyldiethylamine, N-methylpyrrolidone, dimethylethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, choline, pyrrole, piperidine, 1,8-diazabicyclo [5.4.0]- Examples include 7-undecene and 1,5-diazabicyclo [4.3.0] -5-nonane.
Among these, tetramethylammonium hydroxide (TMAH), potassium hydroxide and the like are preferably used in the present invention.
The concentration of the alkali compound in the aqueous alkali solution varies depending on the type of the alkali compound used, but in the case of an organic alkali, it is preferably 0.05 to 10% by mass, more preferably 0.1 to 7% by mass. . For example, when tetramethylammonium hydroxide (TMAH) is used, the concentration is preferably 0.5 to 2.5% by mass.
In addition, 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 such a dilute alkaline aqueous solution and use it as a developer.

The developing time is usually 30 to 600 seconds, and a known method such as a liquid piling method, a dipping method, or a shower developing method can be adopted as the developing method. Thereafter, washing with running water is performed for 30 to 90 seconds, for example, and the moisture on the surface is removed by air drying with compressed air, compressed nitrogen, or the like, thereby forming a patterned cured body. Next, the sufficiently hardened core portion 4 can be formed by post-baking for 5 to 600 minutes at a temperature of 30 to 400 ° C. by a heating device such as a hot plate or an oven.
The post-baking conditions for forming the core portion 4 are 3 to 400 ° C. and 5 to 600 minutes.

(5) Formation of upper clad layer In order to form an upper clad layer, first, an upper layer base film 6, an uncured layer (photosensitive layer 18) of the upper layer photosensitive resin composition, and a cover film (not shown). ) Are laminated, and then the cover film is peeled off from the dry film, and then a laminate (dry film) composed of the upper layer base film 6 and the photosensitive layer 18 is formed on the photosensitive layer 18. In a state of being directed downward, transfer (lamination) is performed on the lower clad layer 3 and the core portion 4 ((g) and (h) in FIG. 2). After the transfer, the upper layer base film 6 may be peeled off.
Here, as a transfer method of the dry film, a method of transferring while applying appropriate heat and pressure using a pressure bonding method such as a normal pressure hot roll pressure bonding method, a vacuum heat roll pressure bonding method, or a vacuum heat press pressure bonding method can be given. It is done.
Next, the upper cladding layer 5 is formed by irradiating the photosensitive layer 18 with light 19, and the optical waveguide film 1 can be completed. The upper cladding layer 5 can be post-baked as necessary.
The upper clad layer 5 can also be formed in the same manner as the method for forming the lower clad layer 3 using a liquid photosensitive resin composition.

  The optical waveguide of the present invention can be formed directly on a base material such as a silicon substrate, not in the form of an optical waveguide film. In this case, first, a dry film formed by laminating the base film, the uncured layer (photosensitive layer) of the lower layer photosensitive resin composition, and the cover film is prepared, and then the cover film is peeled off from the dry film. Next, the laminate composed of the base film for the lower layer and the photosensitive layer is transferred (laminated) onto a base material such as a silicon substrate with the photosensitive layer facing downward. After the transfer, the base film is peeled off to form a laminate in which the photosensitive layer is laminated on the substrate. Next, the photosensitive layer of this laminate is irradiated with light to form a lower cladding layer. Thereafter, the core portion and the upper clad layer may be formed in the same manner as in the case of the optical waveguide film described above.

[Example]
Hereinafter, the present invention will be specifically described by way of examples.
[1. Preparation of photosensitive resin composition]
[Composition 1]
After replacing the flask equipped with a dry ice / methanol reflux with nitrogen, charge 3 g of 2,2′-azobisisobutyronitrile as a polymerization initiator and 100 g of methyl isobutyl ketone as an organic solvent until the polymerization initiator is dissolved. Stir. Subsequently, 20 g of 2-hydroxyethyl methacrylate, 25 g of styrene, 35 g of butyl acrylate, 10 g of 8- (methacryloyloxy) tricyclo [5.2.1.0 ^2,6 ] decane, and 10 g of methacrylic acid were added slowly. Stirring was started. Thereafter, the temperature of the solution was raised to 80 ° C., polymerization was carried out at this temperature for 6 hours, and after cooling to room temperature, 23.7 g of methacryloyloxyethyl isocyanate equivalent to 2-hydroxyethyl methacrylate and dilauric acid were added to the resulting solution. Di-n-butyltin (0.13 g) and 2,6-di-t-butyl-p-cresol (0.05 g) were added, the temperature of the solution was raised to 60 ° C., and polymerization was performed at this temperature for 6 hours. A polymer solution having a methacryloyl group was obtained. 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 a copolymer (component (A)). Table 1 shows the blending ratio (mol%) of each component after polymerization.
On the other hand, in a reaction vessel equipped with a stirrer, 13.6 parts by mass of isophorone diisocyanate, 81.7 parts by mass of polypropylene glycol having a number average molecular weight of 2,000, 2,6-di-t-butyl-p-cresol 0.01 A mass part was charged and cooled to 5 to 10 ° C. While stirring, 0.05 parts by mass of di-n-butyltin dilaurate was added and the mixture was stirred for 2 hours while adjusting the temperature to be kept at 30 ° C. or lower, and then the temperature was raised to 50 ° C. and further stirred for 2 hours. . Subsequently, 4.7 parts by mass of 2-hydroxyethyl acrylate (100 parts by mass in total) was added dropwise, and after the completion of the addition, the reaction was performed at 50 to 70 ° C. for 1 hour. The reaction was terminated when the residual isocyanate was 0.1% by mass or less to obtain Compound D-1 (component (D)).
The component (A) and the components (B) to (E) shown in Table 1 were uniformly mixed at the blending ratio shown in Table 1 to obtain a composition 1 that is a photosensitive resin composition.
[Compositions 2-8]
(A) Other than having changed the kind and compounding ratio (mol%) of each component which comprise a component, and the kind and compounding ratio (mass%) of (A)-(E) component as shown in Table 1. In the same manner as Composition 1, Compositions 2 to 8 were obtained.

[2. Evaluation of photosensitive resin composition]
Compositions 1 to 6 and 8 used as the photosensitive resin composition for the core were evaluated as follows. The results are shown in Table 2.
(1) Developability of core part A photosensitive resin composition for a core (compositions 1 to 6, 8) is applied onto a Si wafer and dried to form a photosensitive layer having a thickness of 50 μm, which is made of a photosensitive resin composition. A test body having the following characteristics was prepared. This specimen was immersed in a 1% tetramethylammonium hydroxide (TMAH) aqueous solution for 5 minutes and then rinsed with distilled water for 1 minute.
As a result, the photosensitive layer (corresponding to the uncured portion that was not irradiated with light in the development process) was removed by dissolution, and “○” indicates that development was possible. The uncured portion was not removed by dissolution, and development was impossible. The case was evaluated as “x”.
(2) Photocurability of core part After coating and drying a photosensitive resin composition (compositions 1 to 6, 8) for a core on a Si wafer, 1,500 mJ / cm with a high-pressure mercury lamp lamp. When the photosensitive resin composition was cured when irradiated with ultraviolet rays at an exposure amount of ² , the evaluation was evaluated as “◯”, and the case where it was not cured was evaluated as “x”.

[3. Formation of optical waveguide]
[Example 1]
(A) Preparation of dry film for core After applying composition 1 (see Table 1) to a base film made of polyethylene terephthalate (PET) having a thickness of 50 μm (product number: A4100) with a 75 μm applicator Baked in an oven at 80 ° C. for 10 minutes to prepare a dry film for the core. It was 50 micrometers when the thickness of the composition layer (photosensitive layer) on a base film was measured with the surface profiler.
(B) Preparation of Clad Dry Film After applying composition 7 (see Table 1) to a 50 μm thick polyethylene terephthalate (PET) base film (Toyobo Co., Ltd., product number: A4100) with a 50 μm applicator Then, baking was performed in an oven at 80 ° C. for 10 minutes to prepare a clad dry film (upper layer dry film, lower layer dry film). It was 30 micrometers when the thickness of the composition layer (photosensitive layer) on a base film was measured with the surface profiler.
(C) Production of optical waveguide film The photosensitive layer of the clad dry film was irradiated with UV light having a wavelength of 365 nm and an illuminance of 10 mW / cm ² for 100 seconds to be cured to obtain a film comprising a lower clad layer and a base film. .
The core dry film was transferred onto the upper surface of the lower clad layer of the film so that the photosensitive layer of the core dry film was on the lower side. Next, ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² were irradiated for 100 seconds through a photomask having a line pattern, thereby partially curing the photosensitive layer. Next, this photosensitive layer was immersed in a developer composed of a dilute alkaline aqueous solution (1 mass% tetramethylammonium hydroxide (TMAH) aqueous solution) to dissolve the unexposed portion. Thereafter, it was washed away with distilled water and post-baked at 150 ° C. for 1 hour to form a core portion having a line pattern.
Next, a clad dry film similar to that used for forming the lower clad layer on the upper surface of the core portion and the lower clad layer was laminated and transferred at 80 ° C. using an atmospheric pressure hot roll pressure bonding method. . Then, the upper clad layer was formed by irradiating ultraviolet rays having a wavelength of 365 nm and an illuminance of 10 mW / cm ² for 100 seconds. In this way, an optical waveguide film was obtained.
[Examples 2-3, Comparative Examples 1-4]
An optical waveguide film was produced in the same manner as in Example 1 except that the type of the photosensitive resin composition for the core was changed as shown in Table 2.

[4. Evaluation of optical waveguide film]
Optical waveguide films (Examples 1 to 3, Comparative Examples 1 to 4) were evaluated as follows.
(1) Moisture and heat resistance When the optical waveguide film provided with the lower clad layer, the core portion and the upper clad layer is allowed to stand for 200 hours in an environment at a temperature of 80 ° C. and a humidity of 85%, and then the optical waveguide film does not change. Was marked with “◯”, and “X” when a change such as whitening occurred.
(2) Waveguide loss With respect to the optical waveguide after the moisture and heat resistance test, light having a wavelength of 850 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. A case where the waveguide loss was 0.5 dB / cm or less was rated as “◯”, and a case where the waveguide loss exceeded 0.5 dB / cm was rated as “x”.
The results are shown in Table 2.

From Table 1, it can be seen that Compositions 1, 2, and 8, which are the photosensitive resin compositions of the present invention, can be developed with a dilute aqueous alkali solution and are sufficiently cured by light. Moreover, from Table 2, the optical waveguide films (Examples 1 to 3) using the compositions 1, 2 and 8 as the core photosensitive resin composition have good wet heat resistance and after the wet heat resistance test. It can be seen that the transmission characteristics in are also good.
On the other hand, the composition 3 not belonging to the present invention cannot be developed with a dilute alkaline aqueous solution. The composition 5 is inferior in photocurability. Compositions 4 and 6 have good developability and photocurability, but when the optical waveguide is formed using the composition as a photosensitive resin composition for a core, after the test of moisture and heat resistance and moisture and heat resistance It can be seen that either or both of the transmission characteristics in FIG.

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 1 Optical waveguide film 2 Base film for lower layers 3 Lower clad layer 4 Core part 5 Upper clad layer 6 Base film for upper layers 10 Photosensitive resin composition for lower layers 11 Dry film for lower layers 12 Ultraviolet rays 13 Photosensitive resin composition for cores 14 Dry Film 15 Photomask 16 Ultraviolet 17 Upper layer dry film 18 Uncured photosensitive resin composition layer for upper layer 19 Ultraviolet

Claims (8)

(A) Including the structure represented by the following general formulas (1) to (3), and the proportion of the structure represented by the following general formula (1) is 5 to 40 mol%, the following general formula (2) A polymer having a structure ratio of 30 to 90 mol% and a structure ratio of 5 to 30 mol% represented by the following general formula (3);

(Wherein R ¹ , R ³ and R ⁴ are each independently a hydrogen atom or a methyl group, R ² is an organic group containing a radically polymerizable reactive group, and X and Z are each independently a single bond) Or, it is a divalent organic group, and Y represents an organic group having no polymerizability.)
(B) a compound having one or more ethylenically unsaturated groups in the molecule and having a molecular weight of less than 1,000, and (C) a radical photopolymerization initiator, and blending the compound (B) The amount is 20-150 mass parts with respect to 100 mass parts of polymers of said (A), The photosensitive resin composition for optical waveguides characterized by the above-mentioned. The photosensitive resin composition for an optical waveguide according to claim 1, wherein the general formula (1) has a structure represented by the following general formula (4).

(In the formula, R ¹ and R ⁵ each independently represent a hydrogen atom or a methyl group, and X and Z each independently represent a single bond or a divalent organic group.)   (D) The above-mentioned (A), which has two or more ethylenically unsaturated groups in the molecule and has a polystyrene-equivalent number average molecular weight measured by gel permeation chromatography of 1,000 to 100,000. The photosensitive resin composition for optical waveguides of Claim 1 or 2 containing compounds other than the polymer of these.   (E) The photosensitive resin composition for optical waveguides of any one of Claims 1-3 containing the organic solvent.   5. 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 the photosensitive resin composition.   A dry film for an optical waveguide, comprising a layer made of the photosensitive resin composition according to claim 1.   The photosensitive resin composition for a dry film according to claim 6, wherein the optical waveguide includes a lower clad layer, a core portion, and an upper clad layer, and at least one of the lower clad layer, the core portion, and the upper clad layer. An optical waveguide comprising a cured product of a physical layer, wherein the refractive index of the core portion is at least 0.1% greater than the refractive index of either the lower cladding layer or the upper cladding layer.   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 And a method for producing an optical waveguide, wherein the at least one step includes a step of irradiating and curing the photosensitive resin composition layer of the dry film according to claim 6.

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