KR20070020423A - Photosensitive composition for forming optical waveguide and optical waveguide - Google Patents

Abstract

The present invention provides a photosensitive composition for forming an optical waveguide that can stably exhibit low transmission loss, high heat resistance, and high adhesion to a substrate such as a silicon wafer over a long period of time. The photosensitive composition of this invention contains 5-50 mass% of adamantyl group containing (meth) acrylates, 40-94.99 mass% of other photopolymerizable compounds, and 0.01-10 mass% of photoinitiators. The composition of the present invention is used as both or one of the cladding layers 3, 4 and the core 5 constituting the optical waveguide 1.

Adamantyl group-containing (meth) acrylate, photopolymerization initiator, optical waveguide, photosensitive composition

Description

Photosensitive composition and optical waveguide for optical waveguide formation {PHOTOSENSITIVE COMPOSITION FOR FORMING OPTICAL WAVEGUIDE AND OPTICAL WAVEGUIDE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition for forming an optical waveguide for producing an optical circuit used in an optical communication field or an optical information processing field, and an optical waveguide manufactured using the composition.

In the age of multimedia, due to the demand for high-capacity and high-speed information processing in optical communication systems and computers, a transmission system using light as a transmission medium is used between public communication networks, LANs (local area networks), FA (factory automation), and computers. It is used for communication networks and home wiring.

Among the components constituting such a transmission system, an optical waveguide is a basic element in an optical device, an optical integrated circuit (OEIC), an optical integrated circuit (IC), or the like for realizing large-capacity information transmission such as a movie or moving picture, an optical computer, or the like. Component. In addition, since there is a large demand for optical waveguides, they have been intensively studied, and in particular, high performance and low cost products are required.

As the material of the optical waveguide, various organic polymers are known in addition to multicomponent glass such as quartz glass and soda lime glass.

For example, the core portion is formed of quartz and at least one of the upper cladding layer and the lower cladding layer is formed of an organic polymer such as polymethyl methacrylate, polystyrene, polyimide, polytrifluoroisopropyl methacrylate, or the like. An optical waveguide is proposed (see Japanese Patent Laid-Open No. Hei 10-300955).

<Start of invention>

Since the photosensitive resin composition containing the mixture of the (meth) acrylate monomer used as a material of an optical waveguide is hardened by ultraviolet irradiation of about several minutes, the improvement of productive efficiency and cost reduction can be implement | achieved.

However, conventionally known (meth) acrylate resin compositions have problems such as high transfer loss, insufficient heat resistance, low transfer loss due to moisture absorption, or peeling from the substrate due to curing shrinkage. many.

Moreover, although the photosensitive resin composition containing the fluorine-substituted (meth) acrylate monomers, such as polytrifluoroisopropyl methacrylate, is excellent in the point of a transmission loss, adhesiveness with a base material falls, and a waveguide layer is removed from a base material. There is a problem of peeling.

Accordingly, an object of the present invention is to provide a photosensitive composition for forming an optical waveguide, which can stably exhibit long transmission loss, high heat resistance, and high adhesion to a substrate such as a silicon wafer over a long period of time under adverse conditions.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, when the optical waveguide is formed using the photosensitive composition containing a specific (meth) acrylate and a photoinitiator, it discovered that the outstanding physical property mentioned above is obtained, and this invention Was completed.

That is, the photosensitive composition for optical waveguide formation of this invention is characterized by including an adamantyl group containing (meth) acrylate and a photoinitiator.

As a preferable aspect of this composition, 5-50 mass% of adamantyl-group-containing (meth) acrylate represented by General formula (1) or (2), 40-94.99 mass% of other photopolymerizable compounds, and 0.01-10 mass% of photoinitiators It may include what is included.

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) — or —CH ₂ CH (OH) CH ₂ —, n is an integer from 0 to 10 Is displayed.)

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) — or —CH ₂ CH (OH) CH ₂ —, R ³ is a hydrogen atom, a methyl group Or an ethyl group, n represents an integer of 0 to 10.)

The cured product of the optical waveguide-forming photosensitive composition of the present invention preferably has a glass transition temperature (Tg) of 80 ° C or higher.

The optical waveguide of the present invention is an optical waveguide including a lower cladding layer, a core portion formed in a portion of an area on the lower cladding layer, and an upper cladding layer formed on the upper cladding layer to cover the core portion, wherein the lower cladding layer At least one selected from the core portion and the upper cladding layer includes a cured product of the photosensitive composition described above.

By using the photosensitive resin composition of the present invention, an optical waveguide capable of stably exhibiting long transmission loss, high heat resistance, and high adhesion to a substrate such as a silicon wafer over a long period of time under adverse conditions can be produced.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the optical waveguide containing the cladding layer which consists of the photosensitive composition of this invention.

Best Mode for Carrying Out the Invention

The photosensitive composition for waveguide formation of this invention contains (A) adamantyl group containing (meth) acrylate, (B) the other photopolymerizable compound mix | blended as needed, and (C) photoinitiator. Hereinafter, each component is demonstrated in detail.

[(A) adamantyl group-containing (meth) acrylate]

The (A) adamantyl group-containing (meth) acrylate used in the present invention may be a (meth) acrylate containing an adamantyl group in a molecule, and the kind is not particularly limited.

As an example of adamantyl group containing (meth) acrylate, the compound represented by General formula (1) or general formula (2) is mentioned, for example.

<Formula 1>

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) — or —CH ₂ CH (OH) CH ₂ —, n is an integer from 0 to 10 Is displayed.)

<Formula 2>

(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) — or —CH ₂ CH (OH) CH ₂ —, R ³ is a hydrogen atom, a methyl group Or an ethyl group, n represents an integer of 0 to 10.)

In the formulas (1) and (2), in the case of n = 0, the adamantyl group-containing (meth) acrylate is an ester of an alcohol having an adamantyl group and (meth) acrylic acid. Here, examples of the alcohol having an adamantyl group include 1-adamantanol, 2-adamantanol, 2-methyl-2-adamantanol, and 2-ethyl-2-adamantanol.

In the formulas (1) and (2), the value of n is preferably 0 to 5, more preferably 0 to 3. If the value is within the preferable numerical range, good transmission loss can be maintained even after long term storage under moist heat.

In the present invention, by blending the adamantyl group-containing (meth) acrylate, long-term reliability in addition to improving the heat resistance of the photosensitive composition (increase in glass transition temperature), adhesion to substrates such as silicon wafers (decrease in curing shrinkage) Improvement (long term maintenance of low transmission loss under adverse conditions such as low temperature, high temperature, high humidity, and temperature fluctuations) can be achieved.

The blending ratio of (A) adamantyl group-containing (meth) acrylate in the photosensitive composition of the present invention is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, particularly preferably 15 to 30% by mass. to be. When the said mixing | blending ratio is less than 5 mass%, a problem may arise that a loss may increase after moist heat storage, a big hardening shrinkage may arise, and peeling may generate | occur | produce according to a use condition. When the said compounding ratio exceeds 50 mass%, problems, such as becoming difficult to obtain a desired refractive index, may arise.

[(B) Other Photopolymerizable Compounds]

As (B) another photopolymerizable compound which can be used by this invention, (meth) acrylates other than a component (A), a vinyl group containing compound, etc. are mentioned.

In addition, component (B) may contain one or more unsaturated groups in a molecule, and all monomers, reactive oligomers, and reactive polymers (macro polymers) may be used.

As an example of the (meth) acrylate which has one (meth) acryloyl group in a molecule | numerator, the macromonomer whose number average molecular weights are 3,000-10,000, and another (meth) acrylate are mentioned.

Among these, polymethyl methacrylate (methacryloyl group containing PMMA) containing a methacryloyl group, polystyrene containing a methacryloyl group, etc. are mentioned as an example of a macromonomer.

Examples of other (meth) acrylates are phenoxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meth) acrylate, 3-phenoxy-2-hydroxy Propyl (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, 4-phenylphenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, p-cumyl Phenolethyleneoxy modified (meth) acrylate, 2-bromophenoxyethyl (meth) acrylate, 4-bromophenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylic Phenoxy group-containing (meth) acrylates, such as 2,6-dibromophenoxyethyl (meth) acrylate and 2,4,6-tribromophenoxyethyl (meth) acrylate, and isobornyl (Meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentanyl (meth) Acrylate, dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, acryloylmorpholine, 2-hydroxyethyl (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, iso Propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) Acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (Meth) acrylate, isode (Meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofur Furyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxyethylene glycol (Meth) acrylate, ethoxyethyl (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, diacetone (meth) acrylamide, isobutoxymethyl (meth) Acrylamide, N, N-dimethyl (meth) acrylamide, t-octyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, etc. are mentioned.

As an example of the (meth) acrylate which has two (meth) acryloyl groups in a molecule | numerator, bisphenol containing di (meth) acrylate, alkyldiol diacrylate, and other (meth) acrylate are mentioned.

Among these, examples of the bisphenol-containing di (meth) acrylate include ethylene oxide added bisphenol A di (meth) acrylate, ethylene oxide added tetrabromobisphenol A type di (meth) acrylate, and propylene oxide added bisphenol A. Bisphenol A type epoxy di obtained by epoxy ring-opening reaction of type | mold di (meth) acrylate, a propylene oxide addition tetrabromobisphenol A type di (meth) acrylate, bisphenol A diglycidyl ether, and (meth) acrylic acid ( Tetrabromobisphenol A type epoxy di (meth) acrylate obtained by the epoxy ring-opening reaction of meth) acrylate, tetrabromobisphenol A diglycidyl ether, and (meth) acrylic acid, and a bisphenol F diglycidyl ether ( Bisphenol F type epoxy di (meth) acrylate obtained by the epoxy ring-opening reaction with methacrylic acid, tetrabromo bisphenol F The tetrabromobisphenol F type epoxy di (meth) acrylate etc. which are obtained by the epoxy ring-opening reaction of diglycidyl ether and (meth) acrylic acid are mentioned.

Examples of the alkyldiol diacrylate include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and the like.

Examples of other (meth) acrylates include polyalkylene glycol diacrylates such as ethylene glycol di (meth) acrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate, and neopentyl glycol di (meth) acrylate. And tricyclodecane dimethanol diacrylate.

Examples of the (meth) acrylate having three or more (meth) acryloyl groups in the molecule include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and trimethylolpropane trioxyethyl (meth) acryl Elate, tris (2-acryloyl oxyethyl) isocyanurate, pentaerythritol polyacrylate, etc. are mentioned.

Examples of the vinyl group-containing compound include N-vinylpyrrolidone, N-vinylcaprolactam, vinylimidazole, vinylpyridine and the like.

It is preferable that component (B) contains (meth) acrylate which has two or more (meth) acryloyl groups in a molecule as one part or all in the point of heat resistance improvement of hardened | cured material.

A component (B) may be used individually by 1 type of compounds, and may use 2 or more types of compounds together. The kind and compounding quantity of the compound of component (B) can be suitably determined in consideration of the refractive index made into the objective after the photosensitive composition of this invention hardens.

The blending ratio of the (B) other photopolymerizable compound in the photosensitive composition of the present invention is preferably 40 to 94.99 mass%, more preferably 53 to 89.9 mass%, particularly preferably 65 to 84.5 mass%. If the blending ratio is less than 40% by mass, problems such as difficulty in obtaining a desired refractive index may occur. When the said compounding ratio exceeds 94.99 mass%, it becomes difficult to satisfy all the characteristics calculated | required by optical waveguides, such as long-term reliability, heat resistance (glass transition temperature; Tg), and adhesiveness between waveguides / substrate.

[(C) Photoinitiator]

As a photoinitiator used by this invention, the compound (photoradical polymerization initiator) which generate | occur | produces an active radical species by irradiating active energy rays, such as an ultraviolet-ray, is used preferably.

Examples of photoinitiators include acetophenone, acetophenonebenzyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,2 -Dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxy Benzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propylether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane -1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, thioxanthone, diethyl thioxanthone, 2-isopropyl thioxanthone, 2-chloro thioxanthone, 2- Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphineoxide, bis- (2,6-dimethoxybenzoyl )-2,4,4-trimethylpentylphosphine oxide and the like There.

Moreover, when superposition | polymerization by heating etc. is used, not using photoinitiator other than photoinitiator, since heating for a long time is required until it fully hardens, it is not preferable in production. Moreover, when using a silicon wafer as a board | substrate, when returning to room temperature after thermosetting, there exists a possibility that peeling of an optical waveguide may be caused from the heat shrinkage difference between a base material and an optical waveguide.

The compounding ratio of (C) photoinitiator in the photosensitive composition of this invention becomes like this. Preferably it is 0.01-10 mass%, More preferably, it is 0.1-7 mass%, Especially preferably, it is 0.5-5 mass%. When the said compounding ratio is less than 0.01 mass%, problems, such as a fall of patterning property and a fall of a hardening rate, may arise. When the said compounding ratio exceeds 10 mass%, problems, such as a fall of patterning property and a fall of a transmission characteristic, may arise.

The photosensitive composition of the present invention includes a solvent, a photosensitizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a silane coupling agent, a drawing improver, a thermal polymerization inhibitor, a leveling agent, a surfactant, a colorant, a storage stabilizer, a plasticizer, Lubricants, fillers, anti-aging agents, wettability modifiers, mold release agents and the like can be further blended as necessary.

The photosensitive composition of this invention can be manufactured by mixing each said component by a conventional method.

The viscosity of the photosensitive composition of the present invention is usually 100 to 20,000 cp / 25 ° C, preferably 200 to 10,000 cp / 25 ° C, more preferably 300 to 5,000 cp / 25 ° C. When the said viscosity is too high, application | coating nonuniformity and relief may arise when apply | coating a photosensitive composition to a base material. On the contrary, even if viscosity is too low, the target film thickness may be difficult to be obtained. The said viscosity can be adjusted by determining suitably the kind and compounding quantity of a monomer and a solvent.

The cured product of the photosensitive composition of the present invention obtained by curing by light irradiation such as ultraviolet rays, preferably has the following physical properties.

When using as a material the cured product of the photosensitive composition of the optical waveguide core portion of the present invention, preferably not less than the refractive index n _D ²⁵ is 1.54, more preferably not less than 1.55. If the refractive index is less than 1.54, good transmission characteristics (low transmission loss) may not be obtained.

The case where the cured product of the photosensitive composition of the present invention to provide a cladding layer material for an optical waveguide, that is its refractive index n _D ²⁵ of not less than 0.01 less than the refractive index n _D ²⁵ of the core portion is preferred, and more preferably 0.03 or more is smaller. If the value is 0.01 or more, smaller transmission loss can be obtained.

Further, "a refractive index n _D ^25" refers to the refractive index of the time sikyeoteul pass the light of 589 nm emission lines of Na in 25 ℃.

Glass transition temperature (Tg) of the hardened | cured material of the photosensitive composition of this invention becomes like this. Preferably it is 80 degreeC or more, More preferably, it is 100 degreeC or more, Especially preferably, it is 110 degreeC or more. When the said temperature is less than 80 degreeC, the heat resistance of an optical waveguide may become inadequate.

In addition, "glass transition temperature" means the temperature which the loss tangent at the vibration frequency of 10 Hz in a resonant dynamic viscoelasticity measuring device shows a maximum value.

It is preferable that it is 10% or less, and, as for the cure shrinkage rate of the hardened | cured material of the photosensitive composition of this invention, it is more preferable that it is 8% or less. When the said cure shrinkage rate exceeds 10%, adhesiveness with respect to base materials, such as a silicon wafer, falls, and peeling from a base material tends to arise depending on a use condition.

The photosensitive composition of this invention can be used as a material of both or one of the core part and cladding layer which comprise an optical waveguide. The photosensitive composition of the present invention is preferably used at least as a lower cladding layer material in view of having excellent adhesion to a substrate.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically an example of the optical waveguide containing the cladding layer which consists of the photosensitive composition of this invention.

In Fig. 1, the optical waveguide 1 includes a substrate 2 such as a silicon wafer, a lower cladding layer 3, an upper cladding layer 4, a core portion 5 protected by these cladding layers 3, 4; ). Among these, the lower cladding layer 3 and the upper cladding layer 4 are formed using the photosensitive composition of this invention.

An example of the method of manufacturing the optical waveguide 1 is as follows.

First, the photosensitive composition of this invention is apply | coated to the surface of the base material 2 by spin coating, and it irradiates and hardens | cures an ultraviolet-ray, and the lower cladding layer 3 is formed. Further, a photosensitive composition other than the core portion is coated on the lower cladding layer 3, and ultraviolet rays are irradiated through a photomask having a predetermined line pattern from the upper side. Since only the part to which ultraviolet-ray was irradiated by this hardens | cures, the non-hardened part other than that is removed with a developing solution, and the core part 5 is obtained.

Subsequently, the optical waveguide 1 is completed by applying the photosensitive composition of the present invention to the upper surfaces of the lower cladding layer 3 and the core portion 5, irradiating and curing ultraviolet rays to form the upper cladding layer 4.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated based on an Example.

[One. Preparation of Photosensitive Composition]

Each component of Table 1 was put in the flask, and it stirred until it turned into a transparent liquid, maintaining liquid temperature at 60 degreeC, and obtained the liquid photosensitive composition ("Composition 1"-"Composition 5" in Table 1).

[2. Evaluation of photosensitive composition]

The physical properties of the obtained photosensitive composition were evaluated as follows.

(a) refractive index

The refractive index at the time of passing the light of Na89 589 nm at 25 degreeC using the Abbe refractometer was measured.

(b) glass transition temperature

After using the applicator to apply the photosensitive composition to the glass substrate to a thickness of 120 ㎛ to form a composition layer, by using a conveyor UV irradiation device in a nitrogen atmosphere by irradiation of 1.0 J / cm ² to the composition layer A cured film was obtained. Subsequently, the temperature dependence of the loss tangent of this cured film was measured, using the resonance type | mold dynamic viscoelasticity measuring apparatus, providing the vibration of a vibration frequency of 10 Hz. The temperature which shows the maximum value of the obtained loss tangent was called glass transition temperature.

(c) curing shrinkage

The liquid density (D1) of the photosensitive composition at 23 degreeC was measured using the specific gravity bottle. Subsequently, the above "2. A glass film having a thickness of 120 µm was formed by the same method as "the glass transition temperature", and it was left to stand in 23 degreeC and 50% of the constant temperature and humidity cabinet for 24 hours. Then, it cut out to the size of 40 mm <^2> , and measured the weight (W1) of the test piece and the weight (W2) in distilled water at 25 degreeC, and the following formula:

Film Density = [W1 / (W1-W2)] × 0.9971

The film density (D2) was calculated from the. The following formula using D1, D2:

Curing shrinkage ratio = [1- (D1 / D2)] × 100

The curing shrinkage ratio was calculated from the results.

(d) peeling resistance

Using the applicator, the photosensitive composition was apply | coated so that it might become a 50 micrometer coating film on the surface-treated quartz substrate. Subsequently, ultraviolet rays were irradiated with an irradiation dose of 500 mJ / cm ² using a conveyor UV irradiation apparatus equipped with a metal halide lamp having a maximum illuminance of 250 mW / cm ² to cure the coating film of the photosensitive composition. In accordance with JIS K5600-5-6, adhesive evaluation was performed by the checkerboard eye peeling test with a cellophane tape. With respect to the checkerboard eye 100, "(circle)" which remained without peeling more than 80 was evaluated as "(circle)", "(triangle | delta)" which left without peeling more than 50 or more and "less than 50" evaluated as "x".

ADA: adamantyl group-containing acrylate (ADA manufactured by Osaka Yuki Kagaku Kogyo Co., Ltd.)

ADMA: adamantyl group-containing methacrylate (Osaka Yuki Chemical Co., Ltd. ADMA)

AA-6: PMMA containing methacryloyl group (Toago Kosei Co., Ltd. make: Macroma AA-6, number average molecular weight 6,000)

V779: tetrabromobisphenol A type epoxy dimethacrylate (made by Nippon Ubikasa: V779)

ACMO: acryloyl morpholine (Gojin company make: ACMO)

NDDA: 1,9-nonanediol diacrylate (made by Daiichi Kogyo Seiyaku Co., Ltd .: LC9A)

TCDDA: tricyclodecane dimethanol diacrylate (Mitsubishi Chemical Corporation make: SA1002)

Ibxma: isobornyl methacrylate (Osaka Yuki Chemical Co., Ltd. make: ib-x)

BR-31: tetrabromophenoxyethyl acrylate (the Dai-ichi Kogyo Seiyaku make: BR-31)

Irg. 184: Cyclohexyl acetophenone (made by Ciba Specialty Chemicals: Irgacure 184)

[3. Manufacture of optical waveguide]

After applying the photosensitive composition for cladding layer shown in Table 2 to the surface of the board | substrate (thickness: 0.5 nm) which consists of a silicon wafer, the ultraviolet-ray of wavelength 365nm and illumination intensity 35mW / cm <^2> is used as a mask aligner 30 Irradiation for a second to cure to form a lower cladding layer (thickness: 40 ㎛).

After apply | coating the photosensitive composition for core parts shown in Table 2 on this lower cladding layer using a spin coater, the ultraviolet-ray of wavelength 365nm and illumination intensity 35mW / cm <^2> 10 was irradiated through the photomask which has an optical waveguide pattern of width 50micrometer. It was exposed by irradiation for a second time. The substrate after exposure was immersed in acetone to dissolve the unexposed portion. Then, it heated at 100 degreeC for 10 minutes, and formed the core part (thickness: 50 micrometers).

In addition, after applying the same photosensitive composition as the lower cladding layer using a spin coater on the upper surface of the lower cladding layer and the core portion, and irradiated with ultraviolet light having a wavelength of 365 nm, roughness 35 mW / cm ² for 30 seconds to harden the upper cladding layer ( Thickness based on the upper surface of the core portion: 40 μm).

In this way, an optical waveguide including the core portion and the cladding layer was completed.

[4. Evaluation of optical waveguide]

The obtained optical waveguide was evaluated as follows.

(a) waveguide loss

After cutting the cross section of the optical waveguide into cleavage, 850 nm of light was inserted through the multimode fiber (50 µm diameter), and the waveguide loss was measured by the cutback method. The cutback was carried out by measuring 5 points with a waveguide of 5 cm in length and 1 cm engraving. The obtained light intensity was plotted against the waveguide length, and the loss value was calculated from the inclination thereof. It was evaluated as "(circle)" that the obtained loss value was 0.5 dB / cm or less, and "x" larger than it.

(b) temperature characteristics

The following (a)-(c) were evaluated.

(A) Changes in optical properties at low temperatures

A waveguide having a waveguide length of 20 mm was prepared, the insertion loss of the initial value was measured, and after leaving at -40 ° C for 500 hours, the insertion loss was measured again, and the amount of change in insertion loss before and after the low temperature treatment was measured. . It was evaluated as "(circle)" that the change amount of insertion loss after low temperature treatment exceeded 1.0 dB with respect to an initial value as "x" and 1.0 dB or less.

(B) change in optical properties under high temperature and high humidity

After measuring the insertion loss of an initial value similarly to the above, after leaving for 1,000 hours in the atmosphere of high temperature, high humidity (temperature: 85 degreeC, relative humidity: 85%), insertion loss is measured again and before and after a high temperature, high humidity process. The amount of change in insertion loss was measured. It was evaluated as "(circle)" that the change amount of insertion loss exceeding 1.0 dB with respect to an initial value as "(circle)" and 1.0 dB or less.

(C) changes in optical properties under heating cycles;

After measuring the insertion loss of an initial value as mentioned above, after 500 cycles of heat cycles which were left to stand at -40 degreeC for 30 minutes, and then left at 85 degreeC for 30 minutes, the insertion loss was measured again, and the insertion loss before and after a heating cycle process was carried out. The amount of change in the loss was measured. It was evaluated as "(circle)" that the change amount of insertion loss exceeding 1.0 dB with respect to an initial value as "(circle)" and 1.0 dB or less.

The results are shown in Table 2.

Claims (4)

An adamantyl group containing (meth) acrylate and a photoinitiator, The photosensitive composition for optical waveguide formation characterized by the above-mentioned. Light containing 5 to 50 mass% of adamantyl group-containing (meth) acrylates represented by the formula (1) or (2), 40 to 94.99 mass% of other photopolymerizable compounds, and 0.01 to 10 mass% of photopolymerization initiators. Photosensitive composition for waveguide formation. <Formula 1>

(Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) — or —CH ₂ CH (OH) CH ₂ —, and n is 0 To an integer of 10.) <Formula 2> (Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents —CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) — or —CH ₂ CH (OH) CH ₂ —, and R ³ represents Hydrogen atom, methyl group or ethyl group, n represents an integer of 0 to 10.) The photosensitive composition for optical waveguide formation of Claim 1 or 2 whose glass transition temperature (Tg) of the hardened | cured material of the said composition is 80 degreeC or more. An optical waveguide comprising a lower cladding layer, a core portion formed in a portion of an area on the lower cladding layer, and an upper cladding layer formed on the lower cladding layer to cover the core portion, wherein the lower cladding layer, the core portion, and the At least one or more selected from the upper cladding layer comprises a cured product of the photosensitive composition according to any one of claims 1 to 3, wherein the optical waveguide.

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