JP2024001786A - Resin sheet with backing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sheet with a backing that can form an optical waveguide which has more superior core moldability and is suppressed in optical transmission loss.

SOLUTION: The present invention relates to a resin sheet with a backing which has a backing and a resin composition layer provided on the backing, wherein the resin composition layer is formed of a resin composition including (A) epoxy resin, (B) photopolymerizable resin containing a carboxyl group, and (C) a photoinitiator, and satisfies at least one of conditions (1) and (2). Here, the backing has a haze of 10% or less measured in accordance with JIS K6714, condition (1), and a contact surface of the backing for the resin composition layer has a mathematical mean roughness (Ra) of 50 nm or less, condition (2).

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a support-attached resin sheet having a resin composition layer containing a photopolymerizable resin.

Technological advances in 5G communications, autonomous driving, IoT, artificial intelligence, big data, etc. are increasing the demand for ultra-high-speed and large-capacity communications. Semiconductor packages, which form the basis of this technology, have traditionally supported high-speed communications by passing high-frequency current through them. However, in recent years, problems such as noise generation, communication loss, and heat generation due to high-speed communication have become apparent. In order to solve these problems, efforts have been made in recent years to implement optical circuits on electrical wiring boards to realize energy saving, low delay, and high-speed communication (Patent Documents 1 and 2).

Research on the introduction of silicon photonics is particularly active in data centers where high-speed transmission is required. Silicon photonics is highly compatible with conventional LSI manufacturing processes. Therefore, by utilizing silicon photonics, it is expected that it will be possible to form nanometer-sized thin wire waveguides at low cost based on the technology cultivated in electronic circuit integration technology.

For example, according to silicon photonics, it is expected that optical integrated circuits will be formed on chips using thin wire waveguides. When manufacturing an opto-electric hybrid board equipped with this chip, a fine optical waveguide is installed on the opto-electric hybrid board in order to extract the signal light from the thin waveguide inside the chip to the outside of the chip and connect it to the wiring between the chips. It is required to provide. However, the finer the optical waveguide is, the easier it is to dissolve in a developer, but on the other hand, the problem is that the surface of the optical waveguide's core becomes more uneven, increasing transmission loss. . Therefore, there is a need for a resin sheet with a support that can form an optical waveguide with suppressed optical transmission loss while having high fine wiring formability associated with better core formability.

JP2019-211540A Patent No. 5771978

An object of the present invention is to provide a resin sheet with a support that has better core forming properties and allows formation of an optical waveguide with suppressed optical transmission loss.

As a result of intensive studies by the present inventors, the haze of the support is 10% or less, or the arithmetic mean roughness (Ra) of the contact surface with the resin composition layer of the support is 50 nm or less. The present inventors have discovered that by using a resin sheet with a support, it is possible to form an optical waveguide that has superior core forming properties and suppresses optical transmission loss, and has completed the present invention.

That is, the present invention includes the following contents.
[1] A resin sheet with a support, comprising a support and a resin composition layer provided on the support,
The resin composition layer is a resin composition layer formed of a resin composition containing (A) an epoxy resin, (B) a photopolymerizable resin containing a carboxyl group, and (C) a photopolymerization initiator,
A resin sheet with a support for forming a core of an optical waveguide, which satisfies at least one of conditions (1) and (2).
Condition (1): The haze of the support measured according to JIS K6714 is 10% or less.
Condition (2): The arithmetic mean roughness (Ra) of the contact surface of the support with the resin composition layer is 50 nm or less.
[2] The resin sheet with a support according to [1] above, which satisfies condition (1).
[3] The resin sheet with a support according to the above [1], which satisfies both conditions (1) and (2).
[4] The resin sheet with a support according to [1] above, wherein the support is a polyethylene terephthalate film.
[5] The resin sheet with a support according to the above [1], wherein the thickness of the support is in the range of 10 μm to 50 μm.
[6] The resin sheet with a support according to [1] above, wherein the resin composition layer has a thickness in the range of 3 μm to 30 μm.
[7] The resin sheet with a support according to [1] above, wherein component (A) contains an epoxy resin having a naphthol aralkyl skeleton.
[8] The resin sheet with a support according to [1] above, wherein component (B) contains a photopolymerizable resin containing an ethylenically unsaturated group and a carboxyl group.
[9] The resin sheet with a support according to the above [1], wherein the component (B) contains a photopolymerizable resin having a naphthol aralkyl skeleton.
[10] The resin sheet with a support according to [1] above, wherein the component (B) contains a carboxylic acid-modified epoxy (meth)acrylate resin.
[11] The resin sheet with a support according to [1] above, wherein the weight average molecular weight (Mw) of component (B) is 18,000 or less.
[12] The resin sheet with a support according to [1] above, wherein the molecular weight of component (C) is 400 or more.
[13] The above, wherein component (C) contains at least one photopolymerization initiator selected from an α-aminoketone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, and an oxime ester photopolymerization initiator. The resin sheet with a support according to [1].
[14] The above [wherein the mass ratio of component (A) to component (B) in the resin composition forming the resin composition layer (component (A)/component (B)) is from 0.1 to 3. 1], the resin sheet with a support.
[15] [1] above, wherein the mass ratio of component (B) to component (C) in the resin composition forming the resin composition layer (component (B)/component (C)) is from 1 to 50. A resin sheet with a support described in .
[16] The resin sheet with a support according to [1] above, wherein the resin composition forming the resin composition layer further contains (D) a reactive diluent.
[17] The resin sheet with a support according to [16] above, wherein component (D) contains a bifunctional or higher-functional (meth)acrylate compound that does not contain a carboxyl group.
[18] The resin sheet with a support according to [16] above, wherein the molecular weight of component (D) is 1,000 or less.
[19] (III) The resin composition layer is formed by laminating the support-attached resin sheet according to any one of [1] to [18] above on the lower cladding layer so that the resin composition layer is in contact with the lower cladding layer. forming on the lower cladding layer;
(IV) a step of placing a mask on the support and subjecting a part of the resin composition layer to light exposure through the mask and the support;
(V) removing the mask and support;
(VI) forming a resin composition pattern by subjecting the resin composition layer to a development process;
(VII) curing the resin composition pattern to form a core on the lower cladding layer;
A method for manufacturing an optical waveguide, including in this order.

The support-attached resin sheet of the present invention has superior core forming properties and can form an optical waveguide with suppressed optical transmission loss.

FIG. 1 is a perspective view schematically showing an optical waveguide in one embodiment. FIG. 2 is a schematic cross-sectional view for explaining step (I) in an embodiment of a method for manufacturing an optical waveguide. FIG. 3 is a schematic cross-sectional view for explaining step (II) in an embodiment of a method for manufacturing an optical waveguide. FIG. 4 is a schematic cross-sectional view for explaining step (III) in an embodiment of a method for manufacturing an optical waveguide. FIG. 5 is a schematic cross-sectional view for explaining step (IV) in an embodiment of a method for manufacturing an optical waveguide. FIG. 6 is a schematic cross-sectional view for explaining step (VI) in an embodiment of a method for manufacturing an optical waveguide. FIG. 7 is a schematic cross-sectional view for explaining step (VII) in an embodiment of a method for manufacturing an optical waveguide. FIG. 8 is a schematic cross-sectional view for explaining step (VIII) in an embodiment of a method for manufacturing an optical waveguide. FIG. 9 is a schematic cross-sectional view for explaining step (IX) in an embodiment of a method for manufacturing an optical waveguide.

Hereinafter, the present invention will be explained in detail based on its preferred embodiments. However, the present invention is not limited to the following embodiments and examples, and may be implemented with arbitrary changes within the scope of the claims of the present invention and equivalents thereof.

<Resin sheet with support>
The resin sheet with a support of the present invention is a resin sheet with a support, which has a support and a resin composition layer provided on the support,
The resin composition layer is a resin composition layer formed of a resin composition containing (A) an epoxy resin, (B) a photopolymerizable resin containing a carboxyl group, and (C) a photopolymerization initiator,
At least one of conditions (1) and (2) is satisfied.
Condition (1): The haze of the support measured according to JIS K6714 is 10% or less.
Condition (2): The arithmetic mean roughness (Ra) of the contact surface of the support with the resin composition layer is 50 nm or less.

The support-attached resin sheet of the present invention is used to form the core of an optical waveguide in the production of an optical waveguide.

The support-attached resin sheet of the present invention has superior core forming properties and can form an optical waveguide with suppressed optical transmission loss.

In condition (1), the haze of the support measured according to JIS K6714 is 10% or less, and from the viewpoint of achieving better core forming properties, it is preferably 9% or less, more preferably 8%. The content is more preferably 7% or less, particularly preferably 6% or less. The lower limit of the haze of the support is not particularly limited, but may be, for example, 0.1%.

In condition (2), the arithmetic mean roughness (Ra) of the contact surface with the resin composition layer of the support is 50 nm or less, and from the viewpoint of achieving better core forming properties, it is preferably 40 nm or less, more preferably 40 nm or less. The thickness is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 15 nm or less.

The resin sheet with a support of the present invention preferably satisfies condition (1), and particularly preferably satisfies both conditions (1) and (2).

It is preferable that the resin sheet with a support of the present invention further satisfies condition (3) from the viewpoint of achieving better core forming properties.
Condition (3): The total light transmittance measured according to JIS K 7361-1 is 70% or more, preferably 80% or more, more preferably 85% or more, and still more preferably 87% or more.

Examples of the support include polyethylene terephthalate film, polyethylene naphthalate film, polypropylene film, polyethylene film, polyvinyl alcohol film, triacetyl acetate film, etc., and polyethylene terephthalate film is particularly preferred.

Examples of commercially available supports include polyethylene terephthalate films such as "Lumirror FB-40" and "QS63" manufactured by Toray Industries, Inc., and "S-25", "S-38" and "PET-12" manufactured by Unitika. These include, but are not limited to. In order to facilitate the removal of the resin composition layer, the surface of these supports is preferably coated with a release agent such as a silicone coating agent.

The thickness of the support is preferably in the range of 5 μm to 100 μm, more preferably in the range of 10 μm to 50 μm. By setting the thickness to 5 μm or more, it is possible to suppress the support from tearing when peeling the support before development, and by setting the thickness to 100 μm or less, it is possible to prevent the support from being torn when exposing from above the support. Resolution can be improved.

Also, a support with low fisheye is preferred. Here, fish eyes refer to foreign matter, undissolved matter, oxidized deterioration products, etc. of the material being incorporated into the film when the film is manufactured by heat-melting, kneading, extrusion, biaxial stretching, casting, etc. It is something that

Furthermore, the resin composition layer may be protected with a protective film. By protecting the resin composition layer side of the resin sheet with a support with a protective film, it is possible to prevent dust and the like from adhering to the surface of the resin composition layer and from scratching it. As the protective film, a film made of the same material as the support described above can be used. The thickness of the protective film is not particularly limited, but is preferably in the range of 1 μm to 40 μm, more preferably in the range of 5 μm to 30 μm, even more preferably in the range of 10 μm to 30 μm. By setting the thickness to 1 μm or more, the handling properties of the protective film can be improved, and by setting the thickness to 40 μm or less, the cost tends to be improved. In addition, the protective film is preferably one in which the adhesive force between the resin composition layer and the protective film is smaller than the adhesive force between the resin composition layer and the support.

A resin sheet with a support can be made by, for example, applying the resin composition described below as it is or dissolving it in an organic solvent to form a varnish onto a support, and then removing the organic solvent by heating or blowing hot air. It can be manufactured by drying to form a resin composition layer. Specifically, first, bubbles in the resin composition are completely removed using a vacuum defoaming method, etc., then the resin composition is applied onto a support, the solvent is removed using a hot air oven or a far infrared oven, and then dried. A resin sheet with a support can be manufactured by laminating a protective film on the obtained resin composition layer, if necessary.

Specific drying conditions vary depending on the curability of the resin composition and the amount of organic solvent in the resin composition, but for resin compositions containing 30% by mass to 60% by mass of organic solvent, drying conditions are 80°C to 120°C. It is preferable that the content of the organic solvent (H) be within the suitable range of the organic solvent (H) described below. Those skilled in the art can appropriately set suitable drying conditions through simple experiments.

The thickness of the resin composition layer is preferably in the range of 1 μm to 500 μm, from the viewpoint of improving handleability and suppressing deterioration of sensitivity and resolution inside the resin composition layer, and 1 μm to 100 μm. The range is more preferably 1 μm to 50 μm, even more preferably 1 μm to 40 μm, and particularly preferably 1 μm to 30 μm.

Examples of coating methods for the resin composition include gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die coating, lip coating, comma coating, blade coating, and roll coating. Examples include a knife coat method, a curtain coat method, a chamber gravure coat method, a slot orifice method, a spray coat method, and a dip coat method.

The resin composition may be applied on the support in several parts, one time, or a combination of different methods. Among these, the die coating method is preferred because it has excellent uniform coating properties. Furthermore, in order to avoid contamination with foreign matter, it is preferable to carry out the coating process in an environment where foreign matter is less likely to occur, such as in a clean room.

The resin composition layer is a resin composition layer formed of a resin composition containing (A) an epoxy resin, (B) a photopolymerizable resin containing a carboxyl group, and (C) a photopolymerization initiator. The resin composition forming the resin composition layer further contains an arbitrary component in addition to (A) an epoxy resin, (B) a photopolymerizable resin containing a carboxyl group, and (C) a photopolymerization initiator. You can stay there. Examples of the optional components include (D) a reactive diluent, (E) a photosensitizer, (F) an inorganic filler, (G) other additives, and (H) an organic solvent. Each component contained in the resin composition will be explained in detail below.

<(A) Epoxy resin>
The resin composition forming the resin composition layer contains (A) an epoxy resin. (A) Epoxy resin is a curable resin having an epoxy group.

(A) Epoxy resins include, for example, bixylenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, and trisphenol type epoxy resin. Epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin , cresol novolac type epoxy resin, phenol aralkyl type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, Examples include cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenolphthalimidine type epoxy resin, etc. . (A) Epoxy resins may be used alone or in combination of two or more.

The resin composition forming the resin composition layer preferably contains, as the epoxy resin (A), an epoxy resin having two or more epoxy groups in one molecule. (A) With respect to 100% by mass of epoxy resin, the proportion of epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, particularly preferably 70% by mass. % or more.

(A) Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resin") and epoxy resins that are solid at a temperature of 20°C (hereinafter referred to as "solid epoxy resins"). There is.) There is. The resin composition forming the resin composition layer may contain only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin. Although it may contain both, it is particularly preferable that it contains only a solid epoxy resin or both a liquid epoxy resin and a solid epoxy resin.

As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferable.

Liquid epoxy resins include glycyol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, and phenol novolac type epoxy resin. Preferred are resins, alicyclic epoxy resins having an ester skeleton, cyclohexanedimethanol type epoxy resins, cycloaliphatic glycidyl ethers, and epoxy resins having a butadiene structure.

Specific examples of liquid epoxy resins include "EX-992L" manufactured by Nagase ChemteX, "YX7400" manufactured by Mitsubishi Chemical, and "HP4032", "HP4032D", and "HP4032SS" manufactured by DIC (naphthalene type epoxy resin). ); “828US”, “jER828EL”, “828EL”, “825”, “Epicote 828EL” manufactured by Mitsubishi Chemical; “850” (bisphenol A type epoxy resin) manufactured by DIC; “jER807” manufactured by Mitsubishi Chemical ", "1750" (bisphenol F type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630", "630LSD", "604" (glycidylamine type epoxy ADEKA's "ED-523T" (glycylol type epoxy resin); ADEKA's "EP-3950L", "EP-3980S" (glycidylamine type epoxy resin); ADEKA's "EP-4088S" ” (dicyclopentadiene type epoxy resin); “ZX1059” manufactured by Nippon Steel Chemical & Materials (mixture product of bisphenol A type epoxy resin and bisphenol F type epoxy resin); “EX-721” manufactured by Nagase ChemteX ( Glycidyl ester type epoxy resin); “EX-991L” manufactured by Nagase ChemteX (epoxy resin containing an alkyleneoxy skeleton and butadiene skeleton); “Celoxide 2021P” manufactured by Daicel (alicyclic epoxy resin having an ester skeleton); "PB-3600" manufactured by Daicel; "JP-100" and "JP-200" manufactured by Nippon Soda (epoxy resin with a butadiene structure); "ZX1658" and "ZX1658GS" manufactured by Nippon Steel Chemical & Materials. (Liquid 1,4-glycidylcyclohexane type epoxy resin); "EG-280" manufactured by Osaka Gas Chemicals (epoxy resin containing fluorene structure); "EX-201" manufactured by Nagase ChemteX (cycloaliphatic glycidyl ether), etc. can be mentioned.

As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable.

Solid epoxy resins include bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, naphthol novolac type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, Naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, bisphenol AF type epoxy resin, phenol aralkyl type epoxy resin, tetraphenylethane type epoxy resin, phenolphthalyl Midine type epoxy resins are preferred.

Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin) manufactured by DIC; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin) manufactured by DIC; “N-690” (cresol novolak type epoxy resin) manufactured by DIC; “N-695” (cresol novolac type epoxy resin) manufactured by DIC; “HP-7200”, “HP-7200HH”, “HP” manufactured by DIC -7200H", "HP-7200L" (dicyclopentadiene type epoxy resin); "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S" manufactured by DIC ", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" manufactured by Nippon Kayaku Co., Ltd. (trisphenol type epoxy resin); "NC7000L" manufactured by Nippon Kayaku Co., Ltd. (naphthol novolac type epoxy resin); “NC3000H”, “NC3000”, “NC3000L”, “NC3000FH”, “NC3100” manufactured by Nippon Kayaku Co., Ltd. (biphenyl type epoxy resin); “ESN475V” and “ESN4100V” manufactured by Nippon Steel Chemical & Materials Co., Ltd. (naphthalene type) epoxy resin); “ESN485” (naphthol type epoxy resin) manufactured by Nippon Steel Chemical &Materials; “ESN375” (dihydroxynaphthalene type epoxy resin) manufactured by Nippon Steel Chemical &Materials; “YX4000H” manufactured by Mitsubishi Chemical; "YX4000", "YX4000HK", "YL7890" (bixylenol type epoxy resin); Mitsubishi Chemical's "YL6121" (biphenyl type epoxy resin); Mitsubishi Chemical's "YX8800" (anthracene type epoxy resin); Mitsubishi “YX7700” manufactured by Chemical Co., Ltd. (phenol aralkyl type epoxy resin); “PG-100” and “CG-500” manufactured by Osaka Gas Chemical Company; “YL7760” manufactured by Mitsubishi Chemical Company (bisphenol AF type epoxy resin); Mitsubishi "YL7800" (fluorene type epoxy resin) manufactured by Chemical Company; "jER1010" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Company; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical Company; Nippon Kayaku Examples include "WHR991S" (phenolphthalimidine type epoxy resin) manufactured by Co., Ltd. These may be used alone or in combination of two or more.

(A) In one embodiment, the epoxy resin preferably includes an epoxy resin having a skeleton selected from a naphthalene skeleton and a biphenyl skeleton, more preferably an epoxy resin having a naphthalene skeleton, and an epoxy resin having a naphthol aralkyl skeleton. Particular preference is given to containing a resin.

(A) The epoxy equivalent of the epoxy resin is preferably 50 g/eq. ～5,000g/eq. , more preferably 60g/eq. ~2,000g/eq. , more preferably 70g/eq. ～1,000g/eq. , even more preferably 80 g/eq. ～500g/eq. It is. Epoxy equivalent is the mass of resin per equivalent of epoxy group. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin (A) is preferably 100 to 5,000, more preferably 250 to 3,000, even more preferably 400 to 1,500. The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by gel permeation chromatography (GPC).

The content of the epoxy resin (A) in the resin composition forming the resin composition layer is preferably from the viewpoint of further improving mechanical strength and insulation reliability when the nonvolatile components of the resin composition are 100% by mass. is 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, particularly preferably 20% by mass or more. From the viewpoint of improving alkali developability, the upper limit is preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, particularly preferably 30% by mass or less. be.

<(B) Photopolymerizable resin containing carboxyl group>
The resin composition forming the resin composition layer contains (B) a photopolymerizable resin containing a carboxyl group. (B) A resin composition containing a photopolymerizable resin containing a carboxyl group can exhibit solubility in an alkaline developer (for example, a 1% by mass aqueous sodium carbonate solution). (B) The number of carboxyl groups per molecule of the photopolymerizable resin containing carboxyl groups may be one, or two or more.

(B) It is preferable that the photopolymerizable resin containing a carboxyl group contains a photopolymerizable resin containing an ethylenically unsaturated group and a carboxyl group. The ethylenically unsaturated group is a photopolymerizable functional group that has a carbon-carbon double bond, and includes, for example, a vinyl group, an allyl group, a propargyl group, a butenyl group, an ethynyl group, a phenylethynyl group, a maleimide group, and a nadiimide group. group, acryloyl group, methacryloyl group, etc., and from the viewpoint of reactivity in photoradical polymerization, acryloyl group and methacryloyl group are preferable. (B) The number of ethylenically unsaturated groups per molecule of the photopolymerizable resin containing a carboxyl group may be one or two or more. In addition, when (B) the photopolymerizable resin containing a carboxyl group contains two or more ethylenically unsaturated groups per molecule, those ethylenically unsaturated groups may be the same or different. Good too.

(B) The photopolymerizable resin containing a carboxyl group is preferably a resin that has both an ethylenically unsaturated group and a carboxyl group, and enables photoradical polymerization and alkaline development.

(B) In one embodiment, the photopolymerizable resin containing a carboxyl group preferably includes a photopolymerizable resin having a skeleton selected from a naphthalene skeleton and a biphenyl skeleton, and includes a photopolymerizable resin having a naphthalene skeleton. It is more preferable that the photopolymerizable resin has a naphthol aralkyl skeleton.

(B) It is particularly preferable that the photopolymerizable resin containing a carboxyl group has the same skeleton as the (A) epoxy resin in one embodiment.

(B) The photopolymerizable resin containing a carboxyl group preferably contains a resin selected from carboxylic acid-modified epoxy (meth)acrylate resin and carboxylic acid-containing (meth)acrylic (meth)acrylate resin, and carboxylic acid-modified More preferably, it contains an epoxy (meth)acrylate resin.

A carboxylic acid-modified epoxy (meth)acrylate resin can be manufactured using an epoxy (meth)acrylate resin. Epoxy (meth)acrylate resin can be produced, for example, by reacting an epoxy resin with acrylic acid or methacrylic acid.

The epoxy resin for producing epoxy (meth)acrylate resin is not particularly limited as long as it is a compound having an epoxy group in the molecule, and examples include bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F Bisphenol-type epoxy resins such as hydrogenated bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and modified bisphenol F-type epoxy resins modified to trifunctional or higher functionality by reacting bisphenol F-type epoxy resins with epichlorohydrin. Biphenol type epoxy resins such as biphenol type epoxy resins and tetramethylbiphenol type; Novolac type epoxy resins such as phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A type novolac type epoxy resins, alkylphenol novolac type epoxy resins; Bisphenol Fluorine-containing epoxy resins such as AF type epoxy resins and perfluoroalkyl type epoxy resins; naphthalene type epoxy resins, dihydroxynaphthalene type epoxy resins, polyhydroxybinaphthalene type epoxy resins, naphthol type epoxy resins, naphthol aralkyl type epoxy resins, binaphthol type epoxy resin, naphthylene ether type epoxy resin naphthol novolac type epoxy resin, naphthalene type epoxy resin obtained by the condensation reaction of polyhydroxynaphthalene and aldehydes, etc. Epoxy resins having a naphthalene skeleton (epoxy resin containing naphthalene skeleton); Xylenol type epoxy resin; dicyclopentadiene type epoxy resin; trisphenol type epoxy resin; tert-butyl-catechol type epoxy resin; epoxy resin containing a condensed ring skeleton such as anthracene type epoxy resin; glycidylamine type epoxy resin; glycidyl ester type epoxy resin; biphenyl type epoxy resin; linear aliphatic epoxy resin; epoxy resin with butadiene structure; alicyclic epoxy resin; heterocyclic epoxy resin; spiro ring-containing epoxy resin; cyclohexanedimethanol type epoxy resin; trimethylol type epoxy resin; tetraphenylethane type epoxy resin; glycidyl group-containing acrylic resin such as polyglycidyl (meth)acrylate, copolymer of glycidyl methacrylate and acrylic ester; fluorene type epoxy resin; halogenated epoxy resin, etc. .

The epoxy resin for producing the epoxy (meth)acrylate resin is preferably an epoxy resin containing an aromatic skeleton from the viewpoint of lowering the average linear thermal expansion coefficient. Here, the aromatic skeleton is a concept that also includes polycyclic aromatics and aromatic heterocycles. Among these, any one of cresol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, and naphthol aralkyl type epoxy resin is preferable.

A carboxylic acid-modified epoxy (meth)acrylate resin can be produced, for example, by reacting an epoxy (meth)acrylate resin with a polyhydric carboxylic acid anhydride.

Examples of polycarboxylic anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetra Examples include carboxylic dianhydrides, and any one of these may be used alone or two or more may be used in combination. Among these, succinic anhydride and tetrahydrophthalic anhydride are preferred, and tetrahydrophthalic anhydride is more preferred.

In one embodiment, the carboxylic acid-modified epoxy (meth)acrylate resin preferably includes a carboxylic acid-modified epoxy (meth)acrylate resin having a skeleton selected from a naphthalene skeleton and a biphenyl skeleton. It is more preferable that a (meth)acrylate resin is included, and it is particularly preferable that a carboxylic acid-modified epoxy (meth)acrylate resin having a naphthol aralkyl skeleton is included.

The carboxylic acid-modified epoxy (meth)acrylate resin can be synthesized by a known method, but a commercially available product may also be used. Specific examples of commercially available products include "CCR-1373H" (acid-modified epoxy acrylate containing a cresol novolak skeleton), "ZCR-8001H" (acid-modified epoxy acrylate containing a biphenyl skeleton), and "ZCR-1569H" manufactured by Nippon Kayaku Co., Ltd. (biphenyl skeleton-containing acid-modified epoxy acrylate), “CCR-1171H” (cresol novolac skeleton-containing acid-modified epoxy acrylate), “ZCR-1797H” (biphenyl skeleton-containing acid-modified epoxy acrylate), “ZAR-” manufactured by Nippon Kayaku Co., Ltd. 2000” (acid-modified epoxy acrylate resin containing bisphenol A skeleton), “ZFR-1491H”, “ZFR-1533H” (acid-modified epoxy acrylate resin containing bisphenol F skeleton), “PR-300CP” manufactured by Showa Denko (cresol novolac) acid-modified epoxy acrylate resin), "CCR-1179" manufactured by Nippon Kayaku Co., Ltd. (epoxy acrylate resin containing a cresol novolac skeleton), and the like. These may be used alone or in combination of two or more.

(B) The acid value of the photopolymerizable resin containing a carboxyl group is preferably 0.1 mgKOH/g or more, more preferably 0.5 mgKOH/g or more, from the viewpoint of improving the alkali developability of the resin composition. , more preferably 1 mgKOH/g or more, 10 mgKOH/g or more, even more preferably 20 mgKOH/g or more, 30 mgKOH/g or more, particularly preferably 40 mgKOH/g or more, 50 mgKOH/g or more. (B) From the viewpoint of improving insulation reliability, the upper limit of the acid value of the photopolymerizable resin containing a carboxyl group is preferably 200 mgKOH/g or less, more preferably 150 mgKOH/g or less, and even more preferably 120 mgKOH/g. It is particularly preferably 100 mgKOH/g or less.

(B) The weight average molecular weight of the photopolymerizable resin containing a carboxyl group is preferably 20,000 or less, more preferably 18,000 or less, still more preferably 15,000 or less. (B) The lower limit of the weight average molecular weight of the photopolymerizable resin containing a carboxyl group is preferably 1,000 or more, more preferably 1,500 or more. The weight average molecular weight is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

The content of the photopolymerizable resin containing carboxyl groups (B) in the resin composition forming the resin composition layer is determined from the viewpoint of improving alkali developability when the nonvolatile components of the resin composition are 100% by mass. Therefore, it is preferably 1% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and particularly preferably 30% by mass or more. From the viewpoint of improving heat resistance, the upper limit thereof is preferably 80% by mass or less, more preferably 70% by mass or less, still more preferably 60% by mass or less, particularly preferably 50% by mass or less. .

The mass ratio of (A) epoxy resin to (B) carboxyl group-containing photopolymerizable resin in the resin composition forming the resin composition layer ((A) component/(B) component) is 0.03 or more. It is preferably 0.1 or more, more preferably 0.3 or more. The upper limit is preferably 10 or less, more preferably 3 or less, and even more preferably 1 or less.

<(C) Photopolymerization initiator>
The resin composition forming the resin composition layer contains (C) a photopolymerization initiator.

(C) Photopolymerization initiators include, for example, α-aminoketone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, oxime ester photopolymerization initiators, α-hydroxyketone photopolymerization initiators, and benzoin-based photopolymerization initiators. Examples include photopolymerization initiators, benzyl ketal photopolymerization initiators, and the like. (C) The photopolymerization initiator may include at least one photopolymerization initiator selected from α-aminoketone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, and oxime ester photopolymerization initiators. Preferably, it is particularly preferable that an α-aminoketone photopolymerization initiator is included. (C) Photopolymerization initiators may be used alone or in combination of two or more.

Examples of the α-aminoketone photopolymerization initiator include 2-methyl-1-phenyl-2-morpholinopropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane- 1-one, 2-methyl-1-(4-hexylphenyl)-2-morpholinopropan-1-one, 2-ethyl-2-(dimethylamino)-1-(4-morpholinophenyl)butane-1- 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one, 2-(dimethylamino)-2-(4-methylphenylmethyl)-1-(4- Examples include morpholinophenyl)butan-1-one (Omnirad 379EG), polyethylene glycol di(β-4-[4-(2-dimethylamino-2-benzyl)butanoylphenyl]piperazine)propionate (Omnipol 910), etc. It will be done. The photopolymerization initiators may be used alone or in combination of two or more.

Examples of acylphosphine oxide photopolymerization initiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, polyoxyethylene glycerin ether tris[phenyl (2,4,6-trimethylbenzoyl)phosphinate] (Polymeric TPO-L) (Omnipol TP) and the like.

Examples of oxime ester photopolymerization initiators include 2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]octan-1-one (OXE01), [1-[9-ethyl-6-( Examples include 2-methylbenzoyl)carbazol-3-yl]ethylideneamino]acetate (OXE02).

Examples of the α-hydroxyketone photopolymerization initiator include 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-[4-(2-hydroxyethoxy)phenyl]-2 -hydroxy-2-methylpropanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, and the like.

Examples of the benzoin-based photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether. Examples of the benzyl ketal photopolymerization initiator include 2,2-dimethoxy-2-phenylacetophenone.

Examples of the benzyl ketal photopolymerization initiator include 2,2-dimethoxy-2-phenylacetophenone and 2,2-diethoxy-2-phenylacetophenone.

(C) The photopolymerization initiator preferably contains a structure selected from a polybutylene glycol structure, a polypropylene glycol structure, and a polyethylene glycol structure, and particularly preferably contains a polyethylene glycol structure.

The molecular weight of the photopolymerization initiator (C) is preferably 200 or more, more preferably 400 or more, even more preferably 600 or more, particularly preferably 800 or more. The upper limit of the molecular weight of the photopolymerization initiator (C) is not particularly limited, but is preferably 4,000 or less, more preferably 2,000 or less.

(C) The photopolymerization initiator is preferably a compound having a maximum absorption wavelength in a wavelength range of 200 nm to 450 nm, more preferably a compound having a maximum absorption wavelength in a wavelength range of 250 nm to 400 nm, and has a maximum absorption wavelength in a wavelength range of 275 nm to 375 nm. Particularly preferred are compounds having absorption wavelengths.

(C) The photopolymerization initiator contains an α-aminoketone photopolymerization initiator preferably at least 10% by mass, more preferably at least 30% by mass, when the photopolymerization initiator (C) is 100% by mass. Preferably it contains 50% by mass or more.

The content of the photopolymerization initiator (C) in the resin composition forming the resin composition layer is preferably 0.1% by mass or more, and more preferably Preferably it is 0.5% by mass or more, more preferably 1% by mass or more. The upper limit thereof is preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 15% by mass or less, particularly preferably 10% by mass or less.

The mass ratio of the (B) carboxyl group-containing photopolymerizable resin to the (C) photopolymerization initiator in the resin composition forming the resin composition layer (component (B)/component (C)) is 0. It is preferably 3 or more, more preferably 1 or more, and even more preferably 3 or more. The upper limit is preferably 200 or less, more preferably 50 or less, and even more preferably 15 or less.

<(D) Reactive diluent>
The resin composition forming the resin composition layer may contain (D) a reactive diluent as an optional component. (D) Reactive diluent is a component that does not correspond to (B) photopolymerizable resin containing a carboxyl group. (D) The reactive diluent does not contain carboxyl groups.

(D) The reactive diluent preferably contains a compound having an ethylenically unsaturated group. (D) The reactive diluent preferably contains a compound having two or more ethylenically unsaturated groups in one molecule. Examples of the ethylenically unsaturated group include an acryloyl group (-CO-CH=CH ₂ ) and a methacryloyl group (-CO-C(CH ₃ )=CH ₂ ). (D) The reactive diluent may be used alone or in combination of two or more.

(D) The reactive diluent includes, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1, Difunctional (meth)acrylate compounds such as 6-hexanediol di(meth)acrylate and 1,9-nonanediol di(meth)acrylate; trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, Trifunctional (meth)acrylate compounds such as glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate; pentaerythritol tetra(meth)acrylate , ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane hexa Examples include (meth)acrylate compounds such as tetrafunctional or higher functional (meth)acrylate compounds such as (meth)acrylate.

(D) The reactive diluent preferably contains a bifunctional or higher functional (meth)acrylate compound that does not contain a carboxyl group, more preferably a trifunctional or higher functional (meth)acrylate compound that does not contain a carboxyl group, It is particularly preferable to include a tetrafunctional or higher functional (meth)acrylate compound that does not contain a carboxyl group.

(D) The molecular weight of the reactive diluent is preferably 1,000 or less, more preferably 800 or less. (D) The lower limit of the molecular weight of the reactive diluent is not particularly limited, but may be, for example, 150 or more.

The content of the reactive diluent (D) in the resin composition forming the resin composition layer is preferably from the viewpoint of further improving photocurability when the nonvolatile component of the resin composition is 100% by mass. The content is 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, particularly preferably 20% by mass or more. The upper limit thereof is preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 40% by mass or less, particularly preferably 30% by mass or less.

The mass ratio of the (B) carboxyl group-containing photopolymerizable resin to the (D) reactive diluent in the resin composition forming the resin composition layer (component (B)/component (D)) is 0. It is preferably 1 or more, more preferably 0.3 or more, and even more preferably 1 or more. The upper limit is preferably 30 or less, more preferably 10 or less, and even more preferably 3 or less.

<(E) Photosensitizer>
The resin composition forming the resin composition layer may contain (E) a photosensitizer as an optional component. (E) By containing a photosensitizer, photocurability can be improved.

(E) Examples of the photosensitizer include thioxanthones and benzophenones.

Specific examples of thioxanthone include 2-isopropylthioxanthone, 1-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone (DETX-S), 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, and polythioxanthone. Examples include butylene glycol bis(9-oxo-9H-thioxanthenyloxy)acetate (Omnipol TX).

Specific examples of benzophenones include 4,4'-bis(diethylamino)benzophenone (EAB) and 4,4'-bis(dimethylamino)benzophenone.

(E) In one embodiment, the photosensitizer preferably contains a structure selected from a polybutylene glycol structure, a polypropylene glycol structure, and a polyethylene glycol structure, and particularly preferably contains a polybutylene glycol structure.

(E) The molecular weight of the photosensitizer is preferably 200 or more. (E) The upper limit of the molecular weight of the photosensitizer is not particularly limited, but is preferably 4,000 or less, more preferably 2,000 or less.

(E) The photosensitizer is preferably a compound having a maximum absorption wavelength in a wavelength range of 200 nm to 450 nm, more preferably a compound having a maximum absorption wavelength in a wavelength range of 300 nm to 400 nm, and has a maximum absorption wavelength in a wavelength range of 325 nm to 375 nm. Particularly preferred are compounds having absorption wavelengths.

(E) The lowest excited triplet energy level of the photosensitizer is higher than the excited triplet energy level of (C) the photopolymerization initiator from the viewpoint of efficiently propagating energy to the photopolymerization initiator. Preferably high. (E) The lowest excited triplet energy level of the photosensitizer is preferably 0.1 kcal/mol to 20 kcal/mol higher than the excited triplet energy level of (C) the photopolymerization initiator, more preferably 0. .1 kcal/mol to 15 kcal/mol higher, particularly preferably 0.1 kcal/mol to 10 kcal/mol higher.

The content of the photosensitizer (E) in the resin composition forming the resin composition layer is preferably 5% by mass or less, more preferably It is 3% by mass or less, more preferably 2% by mass or less, particularly preferably 1% by mass or less. The lower limit is, for example, 0% by mass or more, 0.001% by mass or more, and from the viewpoint of further improving photocurability, preferably 0.01% by mass or more, more preferably 0.05% by mass or more. It is.

<(F) Inorganic filler>
The resin composition forming the resin composition layer may contain (F) an inorganic filler as an optional component. (F) The inorganic filler is contained in the resin composition in the form of particles.

(F) An inorganic compound is used as the material for the inorganic filler. (F) Materials for the inorganic filler include, for example, silica, alumina, aluminosilicate, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, Boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate , titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Further, as the silica, spherical silica is preferable. (F) The inorganic filler may be used alone or in combination of two or more in any ratio.

(F) Commercially available inorganic fillers include, for example, "UFP-30" manufactured by Denka Kagaku Kogyo Co., Ltd.; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumikin Materials; "SC2500SQ", "SO-C4", "SO-C2", "SO-C1", "SC2300-SVJ", "SC2050-SXF", "YC100C", "YA050C", "YA050C-MJE", "YA010C" ", "Y50SZ-AM1"; Denka's "UFP-30"; Tokuyama's "Silfill NSS-3N", "Silfill NSS-4N", "Silfill NSS-5N"; Denka's "DAW-" 03'', ``FB-105FD'', etc.

(F) The average particle size of the inorganic filler is not particularly limited, but is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 1 μm or less, even more preferably 0.5 μm or less, particularly preferably It is 0.1 μm or less. The lower limit of the average particle size of the inorganic filler (F) is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.02 μm or more, and still more preferably 0.03 μm or more. (F) The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, it can be measured by creating the particle size distribution of the inorganic filler on a volume basis using a laser diffraction scattering type particle size distribution measuring device, and using the median diameter as the average particle size. The measurement sample can be obtained by weighing 100 mg of the inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them using ultrasonic waves for 10 minutes. The measurement sample was measured using a laser diffraction particle size distribution measuring device using a light source wavelength of blue and red, and the volume-based particle size distribution of the inorganic filler was measured using a flow cell method. The average particle size was calculated as the median diameter. Examples of the laser diffraction particle size distribution measuring device include "LA-960" manufactured by Horiba, Ltd.

(F) The specific surface area of the inorganic filler is not particularly limited, but is preferably 1 m ² /g or more, more preferably 10 m ² /g or more, even more preferably 20 m ² /g or more, particularly preferably 40 m 2 /g. ² /g or more. The upper limit of the specific surface area of the inorganic filler (F) is not particularly limited, but is preferably 160 m ² /g or less, more preferably 130 m ² /g or less, even more preferably 100 m ² /g or less. The specific surface area of the inorganic filler is determined by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountec) according to the BET method, and calculating the specific surface area using the BET multipoint method. You can get it by doing that.

(F) The inorganic filler is preferably surface-treated with an appropriate surface treatment agent. The surface treatment can improve the moisture resistance and dispersibility of the inorganic filler (F). Examples of surface treatment agents include vinyl silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 3-glycidoxypropylmethyldimethoxysilane. , 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane and other epoxy-based silane coupling agents; styryl-based such as p-styryltrimethoxysilane Silane coupling agent; methacrylic silane coupling agent such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane; Acrylic silane coupling agents such as 3-acryloxypropyltrimethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane , 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N - Amino-based silane coupling agents such as phenyl-8-aminooctyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane; tris-(trimethoxysilylpropyl)isocyanurate, etc. Isocyanurate-based silane coupling agents; ureido-based silane coupling agents such as 3-ureidopropyltrialkoxysilane; mercapto-based silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, etc. ; Isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane; and silane coupling agents such as acid anhydride-based silane coupling agents such as 3-trimethoxysilylpropylsuccinic anhydride. Furthermore, the surface treatment agents may be used alone or in combination of two or more in any ratio.

(F) The inorganic filler preferably includes an inorganic filler surface-treated with a surface treatment agent selected from a vinyl-based silane coupling agent and an amino-based silane coupling agent; It is particularly preferable to include a surface-treated inorganic filler.

Commercially available surface treatment agents include, for example, "KBM-1003", "KBE-1003" (vinyl silane coupling agent); "KBM-303", "KBM-402", and "KBE-1003" manufactured by Shin-Etsu Chemical Co., Ltd. KBM-403", "KBE-402", "KBE-403" (epoxy silane coupling agent); "KBM-1403" (styryl silane coupling agent); "KBM-502", "KBM-503" , "KBE-502", "KBE-503" (methacrylic silane coupling agent); "KBM-5103" (acrylic silane coupling agent); "KBM-602", "KBM-603", "KBM-" 903'', ``KBE-903'', ``KBE-9103P'', ``KBM-573'', ``KBM5783'', ``KBM-575'' (amino-based silane coupling agent); ``KBM-9659'' (isocyanurate-based silane coupling agent); ring agent); "KBE-585" (ureide-based silane coupling agent); "KBM-802", "KBM-803" (mercapto-based silane coupling agent); "KBE-9007N" (isocyanate-based silane coupling agent); ); "X-12-967C" (acid anhydride silane coupling agent); "KBM-13", "KBM-22", "KBM-103", "KBE-13", "KBE-22", "KBE-103", "KBM-3033", "KBE-3033", "KBM-3063", "KBE-3063", "KBE-3083", "KBM-3103C", "KBM-3066", "KBM -7103'' (alkylalkoxysilane compound).

The degree of surface treatment with the surface treatment agent is preferably within a predetermined range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100% by mass of the inorganic filler is preferably surface-treated with a surface treatment agent of 0.2% by mass to 5% by mass, and preferably 0.2% by mass to 3% by mass. It is more preferable that the surface is treated in an amount of 0.3% by mass to 2% by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and 0.2 mg/m ² from the viewpoint of improving the dispersibility of the inorganic filler. The above is more preferable. On the other hand, from the viewpoint of preventing an increase in the melt viscosity of the resin composition or the melt viscosity in sheet form, the amount is preferably 1.0 mg/m ² or less, more preferably 0.8 mg/m ² or less, and 0.5 mg/m ² The following are more preferred.

(F) The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (for example, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler whose surface has been treated with a surface treatment agent, and the mixture is subjected to ultrasonic cleaning at 25° C. for 5 minutes. After removing the supernatant liquid and drying the solid content, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by Horiba, Ltd., etc. can be used.

The content of the inorganic filler (F) in the resin composition forming the resin composition layer is preferably, for example, from the viewpoint of further improving developability when the nonvolatile component in the resin composition is 100% by mass. is 70% by mass or less, more preferably 50% by mass or less, even more preferably 30% by mass or less. The lower limit is, for example, 0% by mass or more, 0.1% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and even more preferably It is 5% by mass or more, particularly preferably 10% by mass or more.

<(G) Other additives>
The resin composition forming the resin composition layer may further contain arbitrary additives. Examples of such additives include thermosetting resins other than epoxy resins such as epoxy acrylate resins, urethane acrylate resins, urethane resins, cyanate resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, and silicone resins. Resin; Thermoplastic resin such as phenoxy resin, polyvinyl acetal resin, polyolefin resin, polysulfone resin; Organic filler such as rubber particles; Organometallic compound such as organic copper compound, organic zinc compound, organic cobalt compound; Hydroquinone, catechol, pyrogallol , polymerization inhibitors such as phenothiazine; leveling agents such as silicone leveling agents and acrylic polymer leveling agents; thickeners such as bentone and montmorillonite; silicone antifoaming agents, acrylic antifoaming agents, fluorine antifoaming agents, Antifoaming agents such as vinyl resin defoaming agents; UV absorbers such as benzotriazole UV absorbers; adhesion improvers such as urea silane; triazole adhesion agents, tetrazole adhesion agents, triazine adhesion agents Adhesion imparting agents such as color imparting agents; Antioxidants such as hindered phenolic antioxidants; Fluorescent brighteners such as stilbene derivatives; Surfactants such as fluorine surfactants and silicone surfactants; Phosphorus Flame retardants such as phosphoric acid ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus, nitrogen-based flame retardants (e.g. melamine sulfate), halogen-based flame retardants, inorganic flame retardants (e.g. antimony trioxide), etc. Dispersants such as phosphate ester dispersants, polyoxyalkylene dispersants, acetylene dispersants, silicone dispersants, anionic dispersants, cationic dispersants; Borate stabilizers, titanate stabilizers, aluminum Examples of stabilizers include nate stabilizers, zirconate stabilizers, isocyanate stabilizers, carboxylic acid stabilizers, and carboxylic anhydride stabilizers. (G) Other additives may be used alone or in combination of two or more in any ratio. (G) The content of other additives can be determined as appropriate by those skilled in the art.

<(H) Organic solvent>
The resin composition forming the resin composition layer may further contain (H) an organic solvent as an optional component. By including component (H), the viscosity of the varnish can be adjusted. (H) Organic solvents include, for example, ketones such as methyl ethyl ketone (MEK) and cyclohexanone, aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene, methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, and propylene. Glycol ethers such as glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, triethylene glycol monoethyl ether, esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, ethyl diglycol acetate, etc. , aliphatic hydrocarbons such as octane and decane, petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. These may be used alone or in combination of two or more. The content when using an organic solvent can be adjusted as appropriate from the viewpoint of coating properties of the resin composition.

(H) The content of the organic solvent is not particularly limited, but when all components in the resin composition are 100% by mass, it is preferably 5% by mass or less, more preferably 3% by mass or less, and It is preferably 2% by mass or less, particularly preferably 1% by mass or less.

<Method for manufacturing resin composition>
The resin composition forming the resin composition layer is prepared by mixing each component appropriately and, if necessary, using a kneading means such as a three-roll mill, a ball mill, a bead mill, a sand mill, or a super mixer, a planetary mixer, or a high-speed rotation mixer. It can be produced by kneading or stirring using a stirring means such as.

<Features of resin sheet with support>
The resin sheet with a support of the present invention is characterized in that it has superior core forming properties and can form an optical waveguide with suppressed optical transmission loss.

Since the resin sheet with a support of the present invention has better core forming properties, in one embodiment, when the resin sheet with a support of the present invention is exposed from the support side, the core that can be formed is It may have a feature that the minimum thin line formation width is smaller. Therefore, in one embodiment, the minimum fine line formation width when evaluated as in Test Example 1 below is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less, particularly preferably 5 μm or less.

Since the resin sheet with a support of the present invention has better core forming properties, in one embodiment, when the resin sheet with a support of the present invention is exposed from the support side, the core formed It may have the feature that resist defects can be suppressed to a small extent. Therefore, in one embodiment, the number of resist defects per 1 mm ² when evaluating resist defects in the core as in Test Example 2 below may be preferably less than 5.

The resin sheet with a support of the present invention may have a feature that it is possible to form an optical waveguide with suppressed optical transmission loss. Therefore, in one embodiment, the optical transmission loss when tested as in Test Example 3 below is preferably less than 2.0 dB/cm, more preferably less than 1.0 dB/cm, particularly preferably 0.5 dB/cm. It can be less than

In the resin composition layer of the resin sheet with a support of the present invention, the non-exposed areas that are not irradiated with light can usually be removed with a developer, and are particularly well removed with sodium carbonate as an alkaline developer. can be done. Therefore, the resin sheet with a support of the present invention can be particularly suitably used for developing with sodium carbonate.

<Optical waveguide>
The support-attached resin sheet of the present invention can be used to form the core of an optical waveguide in the production of an optical waveguide. The core of the optical waveguide has a structure capable of transmitting light and is covered with a cladding layer. Hereinafter, embodiments of the optical waveguide will be described using the drawings.

FIG. 1 is a perspective view schematically showing an optical waveguide 10 of one embodiment. As shown in FIG. 1, the optical waveguide 10 includes a core 100 and a cladding layer 200. The core 100 may be a cured product of the resin composition layer of the support-attached resin sheet of the present invention. Further, the cladding layer 200 may be a cured product of a cladding composition. As the cladding composition, a resin composition that can yield a cured product having a lower refractive index than the cured product of the resin composition layer of the resin sheet with a support of the present invention can be used. As the cladding composition, a photocurable resin composition or a thermosetting resin composition may be used.

Core 100 is provided within cladding layer 200 . Core 100 is covered with cladding layer 200. Usually, the entire circumferential surface of the core 100 is covered with a cladding layer 200. The core 100 and the cladding layer 200 are in direct contact with each other without any other layer in between, and an interface 100I may be formed between the core 100 and the cladding layer 200. Light (not shown) is transmitted within the core 100 from one end (incidence side end) 100A of the core 100 to the other end (output side end) 100B.

The wavelength of light that can be transmitted by the optical waveguide 10 can be selected from various values. By way of example, preferred wavelength ranges for transmitted light may be 840 nm to 860 nm (eg, 850 nm), 1300 nm to 1320 nm (eg, 1310 nm), 1540 nm to 1560 nm (eg, 1550 nm), and the like. Among these, the wavelength range of the light transmitted through the optical transmission line 10 is preferably 1300 nm to 1320 nm.

The optical waveguide 10 may be a single mode optical waveguide or a multimode optical waveguide, but is preferably a single mode optical waveguide. Above all, it is preferable that the optical waveguide 10 is a single mode optical waveguide for light in the above-mentioned preferred wavelength range. For example, the optical waveguide 10 is preferably a single mode optical waveguide for light of 1310 nm.

It is desirable that the width L of the core 100 is appropriately set within a range that allows light transmission. Specifically, the range of the width L of the core 100 is preferably 0.5 μm or more, more preferably 1 μm or more, particularly preferably 2 μm or more, and preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. However, it may be 10 μm or less or 5 μm or less. The width L of the core 100 corresponds to the line width (line) of the core 100 when viewed from the thickness direction.

It is desirable that the spacing S between the cores 100 is appropriately set within a range that allows light transmission. The specific range of the spacing S between the cores 100 is preferably 50 μm or more, more preferably 70 μm or more, particularly preferably 100 μm or more, and preferably 1000 μm or less, more preferably 500 μm or less, particularly preferably 300 μm or less. The interval S between the cores 100 corresponds to the interval (space) between the cores when viewed from the thickness direction.

It is desirable that the thickness T of the core 100 is appropriately set within a range that allows light transmission. The specific range of the thickness T of the core 100 is preferably 0.5 μm or more, more preferably 1 μm or more, particularly preferably 2 μm or more, and preferably 50 μm or less, more preferably 30 μm or less, particularly preferably 20 μm or less. Yes, it may be 10 μm or less.

The thickness of the cladding layer 200 is greater than the thickness of the core 100. The specific thickness of the cladding layer 200 is preferably 5 μm or more, more preferably 7 μm or more, particularly preferably 10 μm or more, and preferably 40 μm or less, more preferably 30 μm or less, particularly preferably 20 μm or less.

The optical waveguide 10 may include any elements other than the core 100 and the cladding layer 200, if necessary. For example, the optical waveguide 10 may include a base material 300. In an optical waveguide 10 including a base material 300, a cladding layer 200 is usually provided on the base material 300, and a core 100 is provided within the cladding layer 200.

As the base material 300, a hard substrate such as a glass substrate, a metal substrate, a ceramic substrate, a wafer, a circuit board, etc. may be used. Examples of wafers include silicon wafers, gallium arsenide (GaAs) wafers, indium phosphide (InP) wafers, gallium phosphide (GaP) wafers, gallium nitride (GaN) wafers, gallium telluride (GaTe) wafers, and zinc selenium (ZnSe). A semiconductor wafer such as a wafer or a silicon carbide (SiC) wafer may be used, or a pseudo wafer may be used. As the pseudo wafer, for example, a plate-shaped member including a mold resin and an electronic component embedded in the mold resin can be used. Examples of the circuit board include a glass epoxy board, a metal board, a polyester board, a polyimide board, a BT resin board, a thermosetting polyphenylene ether board, and the like. Note that the circuit board herein refers to a board on which a patterned conductor layer (circuit) is formed on one or both sides of the board as described above. Further, as the substrate 300, a film made of a plastic material such as polyethylene terephthalate, polyimide, polyester, etc. may be used. Furthermore, a flexible circuit board may be employed as the substrate 300.

Further, the optical waveguide 10 may include a protective layer (not shown) that protects the core 100 and the cladding layer 200 as an optional element. The protective layer may be provided, for example, to cover the surface of the cladding layer 200 opposite to the base material 300.

The optical waveguide 10 can have small transmission loss, as described above. Further, since the optical waveguide 10 can be formed using a resin composition having excellent core forming properties, it is possible to form fine core wiring, and it is possible to form the optical waveguide 10 with a small line width L as described above. .

The optical waveguide 10 can be manufactured using the resin sheet with a support of the present invention. For example, the optical waveguide 10 is
(I) forming a first cladding composition layer formed of a cladding composition on a base material;
(II) a step of curing the first cladding composition layer to form a lower cladding layer on the base material;
(III) laminating the resin sheet with a support of the present invention on the lower cladding layer so that the resin composition layer is in contact with the lower cladding layer to form the resin composition layer on the lower cladding layer;
(IV) a step of placing a mask on the support and subjecting a part of the resin composition layer to light exposure through the mask and the support;
(V) removing the mask and support;
(VI) forming a resin composition pattern by subjecting the resin composition layer to a development process;
(VII) curing the resin composition pattern to form a core on the lower cladding layer;
(VIII) forming a second cladding composition layer made of a cladding composition on the lower cladding layer so as to cover the core;
(IX) curing the second cladding composition layer to form an upper cladding layer on the lower cladding layer so as to cover the core;
It can be manufactured by a method including in this order.

FIG. 2 is a schematic cross-sectional view for explaining step (I) in an embodiment of a method for manufacturing an optical waveguide. As shown in FIG. 2, in one embodiment, the method for manufacturing an optical waveguide includes (I) forming a first cladding composition layer 210 made of a cladding composition on a base material 300.

There is no particular restriction on the method of forming the first cladding composition layer 210. For example, the first cladding composition layer 210 may be formed by applying a cladding composition onto the base material 300. From the viewpoint of smooth application, a varnish-like cladding composition may be prepared and the varnish-like cladding composition may be applied.

Application methods include, for example, gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die coating, lip coating, comma coating, blade coating, roll coating, and knife coating. method, curtain coating method, chamber gravure coating method, slot orifice method, spin coating method, slit coating method, spray coating method, dip coating method, hot melt coating method, bar coating method, applicator method, air knife coating method, curtain flow coating methods, offset printing method, brush coating method, screen printing method, etc.

The cladding composition may be applied once or divided into multiple times. Further, different coating methods may be combined. In order to avoid contamination with foreign matter, it is preferable that the coating be carried out in an environment where little foreign matter is generated, such as a clean room.

After applying the cladding composition, the first cladding composition layer 210 may be dried, if necessary. Drying can be performed using a drying device such as a hot air oven or a far-infrared oven. The drying conditions are preferably set appropriately depending on the composition of the cladding composition. To give a specific example, the drying temperature is preferably 50°C or higher, more preferably 70°C or higher, particularly preferably 80°C or higher, and preferably 150°C or lower, more preferably 130°C or lower, particularly preferably 120°C. It is as follows. Further, the drying time is preferably 30 seconds or more, more preferably 60 seconds or more, particularly preferably 120 seconds or more, and preferably 60 minutes or less, more preferably 20 minutes or less, particularly preferably 5 minutes or less.

The first cladding composition layer 210 may be formed using, for example, a cladding resin sheet including a support and a cladding composition layer formed of a cladding composition provided on the support. good. For example, by laminating the cladding composition layer of the cladding resin sheet onto the base material 300, the first cladding composition layer 210 can be formed on the base material 300. Lamination is performed by pressing the cladding composition layer of the cladding resin sheet onto the base material 300 while heating. This lamination is preferably performed under reduced pressure by a vacuum lamination method. Furthermore, before lamination, a preheating process may be performed to heat the cladding resin sheet and the base material, if necessary.

The laminating conditions are, for example, a compression temperature (laminate temperature) of 70°C to 140°C, a compression pressure of 1kgf/cm ² to 11kgf/cm ² (9.8×10 ⁴ N/m ² to 107.9×10 ⁴ N/ m ² ) and the pressure bonding time is 5 seconds to 300 seconds. Furthermore, lamination is preferably performed under reduced pressure with an air pressure of 20 mmHg (26.7 hPa) or less. Lamination may be performed in a batch manner or in a continuous manner using rolls.

The vacuum lamination method can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum applicator manufactured by Nikko Materials, a vacuum pressurized laminator manufactured by Meiki Seisakusho, a roll dry coater manufactured by Hitachi Industries, and a vacuum laminator manufactured by Hitachi AIC. be able to.

When the first cladding composition layer 210 is formed using a cladding resin sheet provided with a support, the support of the cladding resin sheet is usually peeled off at an appropriate time before step (III).

In one embodiment, the method for manufacturing an optical waveguide includes, after step (I), a step (II) of curing the first cladding composition layer 210 to form a lower cladding layer 220 on the base material 300. In this step (II), for example, the first cladding composition layer 210 may be cured by heat treatment. The conditions for heat treatment may be selected depending on the type and amount of the resin component in the cladding composition, preferably in the range of 150°C to 250°C for 20 minutes to 180 minutes, more preferably in the range of 160°C to 230°C. may range from 30 minutes to 120 minutes. The heat treatment is preferably performed in an inert atmosphere such as a nitrogen atmosphere.

Further, the first cladding composition layer 210 may be cured by exposure treatment. In one example, the specific exposure amount range is preferably 10 mJ/cm ² or more, more preferably 50 mJ/cm ² or more, particularly preferably 200 mJ/cm ² or more, and preferably 10,000 mJ/cm ² or less, It is more preferably 8,000 mJ/cm ² or less, still more preferably 4,000 mJ/cm ² or less, particularly preferably 1,000 mJ/cm ² or less. Alternatively, the first cladding composition layer 210 may be cured by combining exposure treatment and heat treatment.

FIG. 3 is a schematic cross-sectional view for explaining step (II) in an embodiment of a method for manufacturing an optical waveguide. By curing the first cladding composition layer 210 in step (II), a lower cladding layer 220 is formed on the base material 300, as shown in FIG. The lower cladding layer 220 forms a part of the cladding layer 200.

FIG. 4 is a schematic cross-sectional view for explaining step (III) in an embodiment of a method for manufacturing an optical waveguide. In one embodiment, the method for manufacturing an optical waveguide includes, after step (II), as shown in FIG. The method includes a step of laminating the lower cladding layer 220 to form the resin composition layer 110 on the lower cladding layer 220 .

Formation of the resin composition layer 110 is performed using the resin sheet with a support of the present invention. By bringing the resin composition layer of the support-attached resin sheet of the present invention into contact with the lower cladding layer 220 and laminating it, the resin composition layer 110 can be formed on the lower cladding layer 220. For laminating the resin sheet with a support of the present invention, the same conditions as for laminating the resin sheet for cladding can be used.

FIG. 5 is a schematic cross-sectional view for explaining step (IV) in an embodiment of a method for manufacturing an optical waveguide. In one embodiment of the method for manufacturing an optical waveguide, as shown in FIG. 5, after step (III), (IV) a mask 400 is placed on the support 120 and the resin composition is The method includes a step of subjecting a portion of the material layer 110 to exposure treatment.

In step (IV), a latent image is formed on the resin composition layer 110 by subjecting a portion of the resin composition layer 110 to an exposure treatment. In the exposure treatment in step (IV), a mask 400 having a light-transmitting part 410 and a light-blocking part 420 is placed on the support 120, and then light P is applied to the resin composition layer 110 through the mask 400 and the support 120. This is done by irradiating the The light P passes through the light-transmitting section 410 and enters the exposed section 111, but cannot pass through the light-blocking section 420 and therefore cannot enter the non-exposed section 112. The resin composition layer 110 can be provided with an exposed portion 111 and a non-exposed portion 112 corresponding to the transparent hardened portion 410 and the light shielded portion 420.

The transparent portion 410 of the mask 400 is formed to have a planar shape corresponding to the pattern of the core of the optical waveguide. The light shielding portion 420 of the mask 400 is formed to have a planar shape corresponding to the core-free portion of the optical waveguide. Unless otherwise specified, "planar shape" refers to the shape viewed from the thickness direction. The light-transmitting portion 410 formed in a planar shape corresponding to the core is sometimes referred to as a "mask pattern" hereinafter.

As the light P used in the exposure treatment in step (IV), it is preferable to use an appropriate actinic ray depending on the composition of the resin composition. The wavelength of the actinic light is usually 190 nm to 1000 nm, preferably 240 nm to 550 nm, but light of other wavelengths may be used. Specific examples of the active light source include ultraviolet rays, visible light, electron beams, X-rays, etc., and ultraviolet rays are particularly preferred. The exposure amount of the light P is preferably set so that a desired core can be formed after curing in step (VIII). In one example, the specific exposure amount range in step (VI) is preferably 10 mJ/cm ² or more, more preferably 50 mJ/cm ² or more, particularly preferably 200 mJ/cm ² or more, and preferably 10, 000 mJ/cm ² or less, more preferably 8,000 mJ/cm ² or less, still more preferably 4,000 mJ/cm ² or less, particularly preferably 1,000 mJ/cm ² or less.

In one embodiment, the method for manufacturing an optical waveguide includes a step (V) of removing the mask 400 and the support body 120 after the step (IV).

In one embodiment, the method for manufacturing an optical waveguide may include the step of (X) preheating the resin composition layer 110 after step (IV) or step (V) and before step (VI). Through step (X), the solubility of the exposed portion 111 in the developer can be further reduced. Heating in step (X) may be performed using a hot plate or an oven. The heating temperature may be, for example, 40°C or higher and 110°C or lower. Further, the heating time may be, for example, 30 seconds or more and 60 minutes or less.

FIG. 6 is a schematic cross-sectional view for explaining step (VI) in an embodiment of a method for manufacturing an optical waveguide. In one embodiment, the method for manufacturing an optical waveguide includes, after step (V), a step (VI) of performing a development treatment on the resin composition layer 110 to form a resin composition pattern 110'. According to the development process, the latent image formed in step (IV) can be developed. Since the resin composition layer 110 functions as a negative photosensitive resin composition, as shown in FIG. The non-exposed portion 112 (see FIG. 5) of the resin composition layer 110 is removed while remaining as the object pattern 110'. The exposed portion 111 of the resin composition layer 110 remaining after development becomes a resin composition pattern 110' having the same planar shape as the mask pattern of the transparent portion 410 (see FIG. 5) of the mask 400 used in step (IV).

The development method is carried out using a wet development method in which the resin composition layer 110 and a developer are brought into contact. As the developer, an alkaline aqueous solution can be used. As the alkaline aqueous solution, an inorganic base aqueous solution or an organic base aqueous solution can be used.

Examples of the inorganic base aqueous solution include alkali metal hydroxide aqueous solutions such as lithium hydroxide aqueous solution, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution; alkali metal carbonate aqueous solution such as sodium carbonate aqueous solution; sodium hydrogen carbonate aqueous solution, etc. Examples include aqueous alkali metal hydrogen carbonate solutions; aqueous alkali metal phosphate solutions such as sodium phosphate aqueous solutions and potassium phosphate aqueous solutions; alkali metal pyrophosphate aqueous solutions such as sodium pyrophosphate aqueous solutions and potassium pyrophosphate aqueous solutions. Examples of the organic base aqueous solution include a tetraalkylammonium hydroxide aqueous solution. Among these, alkali metal carbonate aqueous solutions are preferred, and sodium carbonate aqueous solutions are more preferred. One type of alkaline aqueous solution may be used alone, or a mixture of two or more types may be used.

If necessary, additives such as a surfactant and an antifoaming agent may be mixed into the developer in order to improve the development effect.

The development time is preferably 10 seconds to 5 minutes. The temperature of the developer during development is not particularly limited, but is preferably 20°C or higher, preferably 50°C or lower, and more preferably 40°C or lower.

Examples of the development method include a paddle method, a spray method, a dipping method, a brushing method, a lapping method, and an ultrasonic method. Among these, the spray method is suitable for improving resolution. When a spray method is employed, the spray pressure is preferably 0.05 MPa to 0.3 MPa.

After the development using the developer, the resin composition layer 110 may be further rinsed. Preferably, rinsing is performed using a solvent different from the developer. For example, the same type of solvent or water as contained in the resin composition may be used for rinsing. The rinsing time is preferably 5 seconds to 1 minute.

After development using a developer, a desmear process may be performed to remove unexposed areas that cannot be completely removed by development. Desmearing may be performed according to various methods used in the manufacture of printed wiring boards and known to those skilled in the art.

In one embodiment, the method for manufacturing an optical waveguide includes, after step (VI), a step (VII) of curing the resin composition pattern 110' to form the core 100 on the lower cladding layer 220. In this step (VII), for example, the resin composition pattern 110' may be cured by heat treatment. The conditions for heat treatment may be selected depending on the type and amount of the resin component in the cladding composition, preferably in the range of 150°C to 250°C for 20 minutes to 180 minutes, more preferably in the range of 160°C to 230°C. may range from 30 minutes to 120 minutes. The heat treatment is preferably performed in an inert atmosphere such as a nitrogen atmosphere.

FIG. 7 is a schematic cross-sectional view for explaining step (VII) in an embodiment of a method for manufacturing an optical waveguide. By curing the resin composition pattern 110' in step (VII), the core 100 is formed on the lower cladding layer 220, as shown in FIG.

In one embodiment, the method for manufacturing an optical waveguide includes, after step (VII), (VIII) forming a second cladding composition layer 230 formed of a cladding composition so as to cover the core 100 on the lower cladding layer 220; It includes a step of forming.

FIG. 8 is a schematic cross-sectional view for explaining step (VIII) in an embodiment of a method for manufacturing an optical waveguide. The second cladding composition layer 230 is formed on the lower cladding layer 220 so as to cover the entire peripheral surface of the core 100 that is not in contact with the lower cladding layer 220.

There is no particular restriction on the method of forming the second cladding composition layer 230. For example, the second cladding composition layer 230 may be formed by applying a cladding composition onto the lower cladding layer 220 so as to cover the core 100. The application of the cladding composition for forming the second cladding composition layer 230 can be performed in the same manner as the application of the cladding composition for forming the first cladding composition layer 210. Further, after applying the cladding composition, the second cladding composition layer 230 may be dried, if necessary. The second cladding composition layer 230 may be dried using the same method and conditions as the first cladding composition layer 210.

The second cladding composition layer 230 may be formed using, for example, a cladding resin sheet. To give a specific example, the second cladding composition layer 230 can be formed on the core 100 by laminating the cladding composition layer of the cladding resin sheet onto the core 100 (and the lower cladding layer 220). The lamination of the resin sheet for cladding to form the second composition layer 230 for cladding can be performed in the same manner as the lamination of the resin sheet for cladding to form the first composition layer 210 for cladding. When the second cladding composition layer 230 is formed using a cladding resin sheet including a support, the support may be peeled off at an arbitrary step.

In one embodiment, the method for manufacturing an optical waveguide includes, after step (VIII), (IX) curing the second cladding composition layer 230 to form an upper cladding layer 240 on the lower cladding layer 220 so as to cover the core 100. It includes a step of forming. Curing of the second cladding composition layer 230 in this step (IX) can be performed in the same manner as the curing of the first cladding composition layer 210.

FIG. 9 is a schematic cross-sectional view for explaining step (IX) in an embodiment of a method for manufacturing an optical waveguide. By curing the second cladding composition layer 230 in step (IX), an upper cladding layer 240 is formed on the lower cladding layer 220 so as to cover the core 100, as shown in FIG. The upper cladding layer 240 forms a part of the cladding layer 200, and the cladding layer 200 is formed from the upper cladding layer 240 and the lower cladding layer 220.

The first cladding composition layer 210 and the second cladding composition layer 230 described above are not particularly limited as long as they exhibit the function of an optical waveguide, but are preferably (A) epoxy resin, This is a composition layer formed of a cladding composition containing (B) a photopolymerizable resin containing a carboxyl group, (C) a photopolymerization initiator, and (F) an inorganic filler. It is preferable that the first cladding composition layer 210 and the second cladding composition layer 230 are composition layers made of the same composition.

The content of the epoxy resin (A) in the cladding composition forming the first cladding composition layer 210 and the second cladding composition layer 230 is based on the nonvolatile components of the cladding composition being 100% by mass. , preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more. The upper limit thereof is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less.

The content of the (B) carboxyl group-containing photopolymerizable resin in the cladding composition forming the first cladding composition layer 210 and the second cladding composition layer 230 is the nonvolatile component of the cladding composition. When 100% by mass, it is preferably 1% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more. The upper limit thereof is preferably 80% by mass or less, more preferably 60% by mass or less, further preferably 50% by mass or less, particularly preferably 40% by mass or less.

The content of the photopolymerization initiator (C) in the cladding composition forming the first cladding composition layer 210 and the second cladding composition layer 230 is such that the nonvolatile components of the cladding composition are 100% by mass. If so, it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably 1% by mass or more. The upper limit thereof is preferably 25% by mass or less, more preferably 20% by mass or less, further preferably 15% by mass or less, particularly preferably 10% by mass or less.

The content of the inorganic filler (F) in the cladding composition forming the first cladding composition layer 210 and the second cladding composition layer 230 is such that the nonvolatile components in the cladding composition are 100% by mass. If so, it is, for example, preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, particularly preferably 60% by mass or less. The lower limit is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, particularly preferably 40% by mass or more.

The cladding composition forming the first cladding composition layer 210 and the second cladding composition layer 230 includes (A) an epoxy resin, (B) a photopolymerizable resin containing a carboxyl group, and (C) a photopolymerizable resin. In addition to the initiator and (F) the inorganic filler, it may further contain arbitrary components. Examples of the optional components include (D) a reactive diluent, (E) a photosensitizer, (G) other additives, and (H) an organic solvent.

The content of the reactive diluent (D) in the cladding composition forming the first cladding composition layer 210 and the second cladding composition layer 230 is such that the nonvolatile components of the cladding composition are 100% by mass. In this case, from the viewpoint of further improving photocurability, the content is preferably 1% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. The upper limit thereof is preferably 60% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, particularly preferably 20% by mass or less.

The optical waveguide 10 includes a cladding layer 200 consisting of a lower cladding layer 220 and an upper cladding layer 240, and a core 100 provided within the cladding layer 200. The method for manufacturing the optical waveguide 10 may further include any steps in combination with the steps described above.

The method for manufacturing the optical waveguide 10 may include, for example, a step of forming a protective layer. Further, the method for manufacturing the optical waveguide 10 may include, for example, a step of dicing the manufactured optical waveguide 10.

The method for manufacturing the optical waveguide 10 may include repeating the steps described above. For example, steps (I) to (XI) may be repeated to manufacture an optical waveguide having a multilayer structure in which cores and cladding layers are alternately provided on the base material 300 in the thickness direction.

<Optoelectric hybrid board>
The opto-electrical hybrid board includes the optical waveguide described above. The opto-electric hybrid board includes an optical waveguide and an electric circuit board. The electric circuit board can include an electronic component and wiring connected to the electronic component. Examples of electronic components include passive components such as capacitors, inductors, and resistors; active components such as semiconductor chips; and the like. The optical waveguide and the wiring of the electric circuit board can be connected via a photoelectric conversion element. The photoelectric conversion element may include a combination of a light emitting element (for example, a surface-emitting light emitting diode) capable of converting electricity into light, and a light receiving element (for example, a photodiode) capable of converting light into electricity. Further, the opto-electric hybrid board may include an optical element such as a mirror for optical path adjustment.

An example of a preferable opto-electrical hybrid board is one that includes a chip in which an optical integrated circuit is formed on a silicon wafer. This chip is expected to be put into practical use using silicon photonics at an early stage, and is expected to be mounted in semiconductor packages, for example. An opto-electrical hybrid board including this chip includes, for example, an electric circuit board, a chip mounted on the electric circuit board, and an optical waveguide. Optical waveguides can be used to connect wiring on an electric circuit board to a chip, or to connect multiple chips.

In general, chips manufactured using silicon photonics often use light with wavelengths of 1310 nm and 1550 nm, with 1310 nm being the mainstream. “Wavepath Fabrication and Low Loss”, 28th Electronics Packaging Society Spring Conference, 2014). The optical waveguide is preferably capable of transmitting light with wavelengths of 1310 nm and 1550 nm or close thereto, for example, preferably capable of transmitting light with wavelengths of 1300 nm to 1320 nm. According to the optical waveguide according to the embodiments described above, it is possible to transmit light of these wavelengths.

Generally, between single mode and multimode, single mode can achieve faster transmission. From the viewpoint of high-speed transmission, a single-mode optical waveguide is preferable as an optical waveguide applied to an opto-electrical hybrid circuit. In a single mode optical waveguide, the core width is preferably small. For example, it is preferable to form a core having a width of 10 μm or less, or 5 μm or less. Further, an optical waveguide having a core with such a small width is preferable from the viewpoint of increasing the degree of freedom in designing the package when the optical waveguide is applied to a semiconductor package. According to the optical waveguide according to the embodiment described above, it is possible to reduce the width of the core as described above.

On the other hand, when connecting a plurality of opto-electric hybrid boards, those boards may be connected via optical fibers. For example, a plurality of opto-electrical hybrid boards may be installed in a rack, and the opto-electrical hybrid boards may be connected to each other with optical fibers. Multi-mode optical fibers are the mainstream for connecting substrates in this way. Therefore, from the viewpoint of enabling connection with the optical fiber, a multimode optical waveguide may be employed as the optical waveguide provided on the opto-electrical hybrid board.

From the viewpoint of increasing versatility, it is desirable that the optical waveguide be applicable to both single mode and multimode. Furthermore, it is desirable to reduce the minimum width of the core of these optical waveguides to increase the degree of freedom in the line width of the core. According to the optical waveguide according to the embodiment described above, the resin composition has excellent core forming properties and can achieve high fine wiring forming ability, so that the minimum width of the core can be made small. Further, according to the optical waveguide according to the embodiment described above, both a single mode and a multimode optical waveguide can be obtained. The optical waveguide according to the embodiment described above can be applied to a wide range of applications. The optical waveguide according to the embodiment described above is suitable for application to an opto-electrical hybrid board because it is applicable to such a wide range and can suppress optical transmission loss.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass," respectively, unless otherwise specified. The temperature condition when there is no particular specification of temperature is room temperature (23° C.), and the pressure condition when there is no particular specification of pressure is atmospheric pressure (1 atm). The weight average molecular weight is a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography.

<Synthesis Example 1: Carboxylic acid-modified epoxy acrylate resin having a naphthol aralkyl skeleton>
325 parts of an epoxy resin having a naphthol aralkyl skeleton ("ESN-475V" manufactured by Nippon Steel Chemical & Materials, epoxy equivalent: 325) was placed in a flask equipped with a gas introduction tube, a stirring device, a cooling tube and a thermometer, and the carbitol 340 parts of acetate was added and dissolved by heating, and 0.46 part of hydroquinone and 1 part of triphenylphosphine were added. This mixture was heated to 95-105°C, 72 parts of acrylic acid was gradually added dropwise, and the mixture was allowed to react for 16 hours. The reaction product was cooled to 80 to 90°C, 80 parts of tetrahydrophthalic anhydride was added, reacted for 8 hours, and cooled. The amount of solvent was adjusted to obtain a resin solution (non-volatile content: 70%) with a solid acid value of 60 mgKOH/g. The weight average molecular weight was 1000.

<Synthesis Example 2: Carboxylic acid-modified epoxy acrylate resin having a methylene dinaphthol skeleton>
162 parts of 1,1'-bis(2,7-diglycidyloxynaphthyl)methane ("EXA-4700" manufactured by Dainippon Ink Chemical Industries, Ltd., epoxy equivalent: 162) was added to a gas inlet pipe, a stirring device, a cooling pipe and a temperature 340 parts of carbitol acetate was added to the flask, and 340 parts of carbitol acetate was added thereto and dissolved by heating, and 0.46 part of hydroquinone and 1 part of triphenylphosphine were added thereto. This mixture was heated to 95-105°C, 72 parts of acrylic acid was gradually added dropwise, and the mixture was allowed to react for 16 hours. The reaction product was cooled to 80 to 90°C, 80 parts of tetrahydrophthalic anhydride was added, reacted for 8 hours, and cooled. In this way, a resin solution (70% non-volatile content) with a solid acid value of 90 mgKOH/g was obtained. The weight average molecular weight was 2,500.

<Example 1: Production of resin sheet 1 with support>
25 parts of the carboxylic acid-modified epoxy acrylate resin obtained in Synthesis Example 1 (containing a naphthol aralkyl skeleton, non-volatile content 70%), naphthol aralkyl type epoxy resin ("ESN-475V" manufactured by Nippon Steel Chemical & Materials Co., Ltd., epoxy equivalent: 330 g) /eq.) 10 parts, α-aminoketone photopolymerization initiator (IGM “Omnipol 910”, polyethylene glycol di(β-4-[4-(2-dimethylamino-2-benzyl)butanoylphenyl]pyrin) 1.3 parts of perazine propionate), 10 parts of a reactive diluent (DPHA manufactured by Nippon Kayaku Co., Ltd., dipentaerythritol hexaacrylate), and 10 parts of methyl ethyl ketone were mixed, and a varnish-like resin was prepared using a high-speed rotating mixer. A composition was prepared.

A mold release agent (“AL-5” manufactured by Lintec Corporation) was uniformly applied with a die coater to a thickness of 1 μm on a polyethylene terephthalate film (“S-25” manufactured by Unitika, thickness 25 μm) and supported. Prepared as a body. The haze of the support prepared according to JIS K6714 was measured and found to be 6%. The arithmetic mean roughness (Ra) of the side of the support to which the varnish-like resin composition was applied was measured using a non-contact interference microscope (manufactured by WYKO Bruker AXS) and found to be 10 nm. The total light transmittance of the support was measured in accordance with JIS K 7361-1 and was found to be 87%.

A varnish-like resin composition was uniformly applied to the surface of the prepared support coated with the mold release agent using a die coater so that the thickness of the resin composition layer after drying was 10 μm, and heated from 80°C to 110°C. ℃ (maximum temperature 110° C.) for 6 minutes to form a resin composition layer. Next, a cover film (biaxially oriented polypropylene film, "MA-411" manufactured by Oji F-Tex Co., Ltd.) is placed on the surface of the resin composition layer, and laminated at 80°C, thereby forming the support/resin composition layer/ A resin sheet with a support having a three-layer structure of a cover film was manufactured.

<Example 2: Production of resin sheet 2 with support>
Instead of 25 parts of the carboxylic acid-modified epoxy acrylate resin (containing a naphthol aralkyl skeleton, nonvolatile content 70%) obtained in Synthesis Example 1, the carboxylic acid-modified epoxy acrylate resin (containing a methylene dinaphthol skeleton, containing a methylene dinaphthol skeleton) obtained in Synthesis Example 2 was used. A resin sheet with a support was produced in the same manner as in Example 1, except that 25 parts (non-volatile content: 70%) were used.

<Example 3: Production of resin sheet 3 with support>
Instead of 25 parts of the carboxylic acid-modified epoxy acrylate resin (containing naphthol aralkyl skeleton, nonvolatile content 70%) obtained in Synthesis Example 1, a carboxylic acid-modified epoxy acrylate resin ("CCR-1373H" manufactured by Nippon Kayaku Co., Ltd., cresol novolak) was used. A resin sheet with a support was produced in the same manner as in Example 1, except that 25 parts of the resin sheet (containing skeleton, acid value 99 mgKOH/g, non-volatile fraction 60%, solvent PGMEA, molecular weight 2800) were used.

<Example 4: Production of resin sheet 4 with support>
Instead of 25 parts of the carboxylic acid-modified epoxy acrylate resin (containing a naphthol aralkyl skeleton, nonvolatile content 70%) obtained in Synthesis Example 1, a carboxylic acid-modified epoxy acrylate resin ("CCR-1171H" manufactured by Nippon Kayaku Co., Ltd., cresol novolak) was used. A resin sheet with a support was produced in the same manner as in Example 1, except that 25 parts (skeleton-containing, acid value 99 mgKOH/g, non-volatile fraction 60%, solvent PGMEA, molecular weight 7500) was used.

<Example 5: Production of resin sheet 5 with support>
Instead of 25 parts of the carboxylic acid-modified epoxy acrylate resin (containing a naphthol aralkyl skeleton, non-volatile content: 70%) obtained in Synthesis Example 1, a carboxylic acid-modified epoxy acrylate resin ("ZCR-8001H" manufactured by Nippon Kayaku Co., Ltd., biphenyl skeleton) was used. A resin sheet with a support was produced in the same manner as in Example 1, except that 25 parts (containing, acid value 109 mgKOH/g, non-volatile fraction 60%, solvent PGMEA, molecular weight 3700) were used.

<Example 6: Production of resin sheet 6 with support>
Furthermore, an α-aminoketone photopolymerization initiator (“Omnirad 379EG” manufactured by IGM, 2-(dimethylamino)-2-(4-methylphenylmethyl)-1-(4-morpholinophenyl)butan-1-one, molecular weight A resin sheet with a support was produced in the same manner as in Example 1 except that 0.3 part of 380.5) was used.

<Example 7: Production of resin sheet 7 with support>
Furthermore, an oxime ester photopolymerization initiator (“Irgacure OXE-02” manufactured by BASF, [1-[9-ethyl-6-(2-methylbenzoyl)carbazol-3-yl]ethylideneamino]acetate, molecular weight 412.5 ) A resin sheet with a support was produced in the same manner as in Example 1, except that 0.01 part of the resin was used.

<Example 8: Production of resin sheet 8 with support>
Furthermore, 2.6 parts of an acylphosphine oxide photopolymerization initiator ("Omnipol TP" manufactured by IGM, polyoxyethylene glycerin ether tris [phenyl (2,4,6-trimethylbenzoyl) phosphinate], molecular weight 900 or more) was used. Except for this, a resin sheet with a support was produced in the same manner as in Example 1.

<Example 9: Production of resin sheet 9 with support>
The same procedure as in Example 1 was carried out, except that 0.1 part of thioxanthone ("Omnipol TX" manufactured by IGM, polybutylene glycol bis (9-oxo-9H-thioxanthenyloxy) acetate, molecular weight 790) was further used. , a resin sheet with a support was manufactured.

<Example 10: Production of resin sheet 10 with support>
A resin sheet with a support was prepared in the same manner as in Example 1, except that 0.3 part of benzophenones ("EAB" manufactured by Tokyo Kasei Kogyo Co., Ltd., 4,4'-bis(diethylamino)benzophenone, molecular weight 343) was used. was manufactured.

<Example 11: Production of resin sheet 11 with support>
Furthermore, 10 parts of spherical silica (“Y50SZ-AM1” manufactured by Admatex, specific surface area 60 m ² /g, average particle size 0.05 μm, solid content 50%) surface-treated with an amino-based silane coupling agent was used. Except for this, a resin sheet with a support was produced in the same manner as in Example 1.

<Example 12: Production of resin sheet 12 with support>
A polyethylene terephthalate film (“PET-12” manufactured by Unitika, thickness 12 μm) was used as a support instead of a support made of polyethylene terephthalate film (“S-25” manufactured by Unitika, thickness 25 μm) coated with a release agent. Except for this, a resin sheet with a support was produced in the same manner as in Example 1. As in Example 1, the haze of the support was measured to be 3%, the arithmetic mean roughness (Ra) was measured to be 30 nm, and the total light transmittance was measured to be 88%.

<Example 13: Production of resin sheet 13 with support>
A polyethylene terephthalate film ("S-38" manufactured by Unitika Co., Ltd., thickness 38 μm) was used as a support instead of a polyethylene terephthalate film ("S-25" manufactured by Unitika Co., Ltd., thickness 25 μm) coated with a release agent. Except for this, a resin sheet with a support was produced in the same manner as in Example 1. As in Example 1, the haze of the support was measured to be 3%, the arithmetic mean roughness (Ra) was measured to be 35 nm, and the total light transmittance was measured to be 88%.

<Example 14: Production of resin sheet 14 with support>
Polyethylene terephthalate film ("Lumirror FB-40" manufactured by Toray Industries, Ltd., thickness 16 μm) was used as a support instead of a support made of polyethylene terephthalate film ("S-25" manufactured by Unitika, thickness 25 μm) coated with a release agent. A resin sheet with a support was produced in the same manner as in Example 1 except for the following. As in Example 1, the haze of the support was measured to be 1%, the arithmetic mean roughness (Ra) was measured to be 8 nm, and the total light transmittance was measured to be 89%.

<Example 15: Production of resin sheet 15 with support>
Except that a polyethylene terephthalate film ("QS63" manufactured by Toray Industries, Inc., thickness 25 μm) was used as a support instead of a polyethylene terephthalate film ("S-25" manufactured by Unitika, thickness 25 μm) coated with a release agent. A resin sheet with a support was produced in the same manner as in Example 1. In the same manner as in Example 1, the haze of the support was measured to be 0.5%, the arithmetic mean roughness (Ra) was measured to be 7 nm, and the total light transmittance was measured to be 90%.

<Comparative Example 1: Production of resin sheet 16 with support>
Instead of a polyethylene terephthalate film (“S-25” manufactured by Unitika Co., Ltd., thickness 25 μm) coated with a release agent, a filler kneaded polyethylene terephthalate film (“PTH-25” manufactured by Unitika Co., Ltd., thickness 25 μm) is supported. A resin sheet with a support was produced in the same manner as in Example 1 except that it was used as a support. As in Example 1, the haze of the support was measured to be 25%, the arithmetic mean roughness (Ra) was measured to be 260 nm, and the total light transmittance was measured to be 85%.

<Comparative Example 2: Production of resin sheet 17 with support>
Instead of a support made of polyethylene terephthalate film (“S-25” manufactured by Unitika, thickness 25 μm) coated with a release agent, a sandblasted polyethylene terephthalate film (“T60” manufactured by Toray Industries, Ltd., thickness 25 μm) was used as a support. A resin sheet with a support was manufactured in the same manner as in Example 1 except that the resin sheet was used. As in Example 1, the haze of the support was measured to be 70%, the arithmetic mean roughness (Ra) was measured to be 300 nm, and the total light transmittance was measured to be 86%.

<Comparative Example 3: Production of resin sheet 18 with support>
Instead of a polyethylene terephthalate film (“S-25” manufactured by Unitika Co., Ltd., thickness 25 μm) coated with a release agent, a roughened polyethylene terephthalate film (“S-25” manufactured by Unitika Co., Ltd., thickness 25 μm) was used. A resin sheet with a support was produced in the same manner as in Example 1 except that it was used as a support. As in Example 1, the haze of the support was measured to be 60%, the arithmetic mean roughness (Ra) was measured to be 560 nm, and the total light transmittance was measured to be 87%.

<Production example 1: Production of resin sheet for cladding>
25 parts of carboxylic acid-modified epoxy acrylate resin obtained in Synthesis Example 1 (containing bisnaphtholmethane skeleton, non-volatile content 70%), naphthol aralkyl type epoxy resin ("ESN-475V" manufactured by Nippon Steel Chemical & Materials Co., Ltd.), epoxy equivalent 330g/eq.) 10 parts, α-aminoketone photopolymerization initiator (IGM “Omnipol 910”, polyethylene glycol di(β-4-[4-(2-dimethylamino-2-benzyl)butanoylphenyl]) 1.3 parts of reactive diluent (DPHA manufactured by Nippon Kayaku Co., Ltd., dipentaerythritol hexaacrylate), spherical silica surface-treated with an amino-based silane coupling agent (Admatex A composition for varnish-like cladding was prepared by mixing 30 parts of "180nmSX-C1" (specific surface area: 20 m ² /g, average particle size: 0.2 μm, solid content: 100%) and 10 parts of methyl ethyl ketone using a high-speed rotating mixer. I prepared something.

A mold release agent (“AL-5” manufactured by Lintec Corporation) was uniformly applied with a die coater to a thickness of 1 μm on a polyethylene terephthalate film (“S-25” manufactured by Unitika, thickness 25 μm) and supported. Prepared as a body.

A varnish-like cladding composition was uniformly applied to the surface coated with the mold release agent of the prepared support using a die coater so that the thickness of the resin composition layer after drying was 10 μm, and heated from 80°C. It was dried at 110° C. (maximum temperature 110° C.) for 6 minutes to form a cladding composition layer. Next, a cover film (biaxially oriented polypropylene film, "MA-411" manufactured by Oji F-Tex Co., Ltd.) is placed on the surface of the resin composition layer, and laminated at 80°C, thereby forming the support/resin composition layer/ A resin sheet for cladding with a three-layer structure of cover film was manufactured.

<Test Example 1: Evaluation of minimum fine line formation width of core>
A substrate was prepared by roughening the copper layer of a glass epoxy substrate (copper-clad laminate) with a copper layer having a thickness of 18 μm using a surface treatment agent containing an organic acid (CZ8100, manufactured by MEC Corporation). . The cladding resin sheet provided with the 10 μm thick cladding composition layer produced in Production Example 1 was laminated onto the prepared substrate at 80°C so that the cladding composition layer was in contact with the substrate, and the first cladding resin sheet was laminated onto the prepared substrate at 80°C. A composition layer was formed. Thereafter, using a projection exposure apparatus (Ushio Inc. "UFX-2240"), ultraviolet light was exposed at an exposure energy such that the number of remaining glossy steps of the 41-step tablet was 8 steps. A quartz glass mask without an exposure pattern was used. After standing at room temperature for 30 minutes, the support was peeled off. Spray development was performed on the entire surface of the first cladding composition layer using a 1% by mass aqueous sodium carbonate solution at 30°C as a developer for 1 minute at a spray pressure of 0.2 MPa. After spray development, a lower cladding layer was formed on the copper-clad laminate by irradiating with ultraviolet rays at 2 J/cm ² and further performing a heat treatment at 170° C. for 1 hour in a nitrogen atmosphere.

The cover films were peeled off from the support-attached resin sheets 1 to 14 having resin composition layers with a thickness of 10 μm produced in Examples and Comparative Examples. The resin sheet with a support is placed on the lower cladding layer so that the resin composition layer of the resin sheet with a support and the lower cladding layer are in contact with each other, and then the resin sheet with a support is placed on the lower cladding layer, and the resin sheet is laminated using a vacuum laminator (“VP160” manufactured by Nikko Materials). They were laminated to form a resin composition layer on the lower cladding layer. The lamination conditions were as follows: evacuation time: 30 seconds, compression temperature: 100° C., compression pressure: 0.7 MPa, and pressurization time: 30 seconds. Thereby, a laminate including a copper-clad laminate, a lower cladding layer, and a resin sheet in this order was obtained.

The resin composition layer was exposed to ultraviolet light using a projection exposure device (Ushio Inc. "UFX-2240") at an exposure energy that resulted in a 41-step tablet with a remaining gloss level of 8 steps. For exposure, a mask pattern was used to draw straight lines with L/S (line/space) of 10 μm/10 μm, 9 μm/9 μm, 8 μm/8 μm, 7 μm/7 μm, 6 μm/6 μm, 5 μm/5 μm, 4 μm/4 μm, and 3 μm/3 μm. This was done using a quartz glass mask. After exposure, the support was peeled off after being allowed to stand at room temperature for 30 minutes. Spray development was carried out over the entire surface of the resin composition layer using a 1% by mass aqueous sodium carbonate solution at 30°C as a developer at a spray pressure of 0.2 MPa for 1 minute. After spray development, the copper clad laminate, the lower cladding layer and the core (cured product of the resin composition pattern) were prepared by irradiating ultraviolet rays at 2 J/cm ² and further heating at 170°C for 1 hour in a nitrogen atmosphere. A sample was obtained.

The obtained sample was observed with a scanning electron microscope (SEM) (magnification: 2000 times), and the minimum thin line formation width (the width of the smallest core among the cores that could be formed) was measured.

<Test Example 2: Evaluation of core resist defects>
The core of the sample obtained in Test Example 1 was observed using a scanning electron microscope (SEM), and the number of resist defects per 1 mm ² of the sample was evaluated based on the following evaluation criteria.
“〇”: Less than 5 resist defects “×”: 5 or more resist defects

<Test Example 3: Measurement of optical transmission loss>
The cover film was peeled from the cladding resin sheet prepared in Production Example 1 and provided with a 10 μm thick cladding composition layer. A resin sheet was placed on a 4-inch silicon wafer so that the cladding composition layer and the silicon wafer were in contact with each other, and laminated using a vacuum laminator ("VP160" manufactured by Nikko Materials). The lamination conditions were as follows: evacuation time: 30 seconds, compression temperature: 100° C., compression pressure: 0.7 MPa, and pressurization time: 30 seconds. Thereafter, the support was peeled off to obtain an intermediate laminate I including a silicon wafer and a first cladding composition layer.

The first cladding composition layer of the obtained intermediate laminate I was exposed using a projection exposure device (Ushio Inc. "UFX-2240") so that the number of remaining gloss steps of the 41 step tablet was 8 steps. Ultraviolet exposure was performed with energy. After exposure, ultraviolet rays were irradiated at 2 J/cm ² . Intermediate laminate I was placed in a clean oven, the temperature was raised from room temperature to 170°C, and after reaching 170°C, heat treatment was performed for 60 minutes in a nitrogen atmosphere to harden the first cladding composition layer. . A lower cladding layer was formed by curing the first cladding composition layer, yielding an intermediate laminate II comprising a silicon wafer and a lower cladding layer.

The cover films were peeled off from the support-attached resin sheets 1 to 14 having resin composition layers with a thickness of 10 μm produced in Examples and Comparative Examples. A resin sheet with a support is placed on the surface of the lower cladding layer of the intermediate laminate II so that the resin composition layer and the lower cladding layer are in contact with each other, and a vacuum laminator ("VP160" manufactured by Nikko Materials) is used. Laminated. The lamination conditions were as follows: evacuation time: 30 seconds, compression temperature: 100° C., compression pressure: 0.7 MPa, and pressurization time: 30 seconds. An intermediate laminate III comprising a silicon wafer, a lower cladding layer, and a resin composition layer in this order was obtained.

The resin composition layer of the intermediate laminate III was exposed to ultraviolet light using a projection exposure device (Ushio Inc. "UFX-2240") at an exposure energy that resulted in a gloss remaining step number of 8 steps on a 41 step tablet. Ta. For exposure, a mask pattern that can draw multiple straight lines with a length of 1 cm at an L/S (line/space) of 5 μm/100 μm, and a mask pattern that can draw multiple straight lines with a length of 2 cm at an L/S (line/space) of 5 μm/100 μm are used. A quartz glass mask having a mask pattern capable of drawing and a mask pattern capable of drawing a plurality of straight lines with a length of 3 cm at L/S (line/space) of 5 μm/100 μm was used. In the L/S of this quartz glass mask, the line corresponds to the width of the core, and the space corresponds to the interval between the cores. After exposure, the support was peeled off after being allowed to stand at room temperature for 30 minutes. Spray development was performed on the entire surface of the resin composition layer using a 1% by mass aqueous sodium carbonate solution at 30° C. as a developer at a spray pressure of 0.2 MPa for 1 minute to form a resin composition pattern. After spray development, ultraviolet irradiation was performed at 2 J/cm ² . Thereafter, the intermediate laminate III was placed in a clean oven, the temperature was raised from room temperature to 170°C, and after reaching 170°C, a heat treatment was performed for 60 minutes in a nitrogen atmosphere to harden the resin composition pattern.

A core was formed by curing the resin composition pattern, yielding an intermediate laminate IV comprising a silicon wafer, a lower cladding layer, and a core in this order.

The cover film was peeled from the cladding resin sheet prepared in Production Example 1 and provided with a 10 μm thick cladding composition layer. A cladding resin sheet was placed on the core of the intermediate laminate IV so that the cladding composition layer and the core were in contact with each other, and laminated using a vacuum laminator ("VP160" manufactured by Nikko Materials). The lamination conditions were as follows: evacuation time: 30 seconds, compression temperature: 100° C., compression pressure: 0.7 MPa, and pressurization time: 30 seconds. Thereafter, the support was peeled off to obtain an intermediate laminate V comprising a silicon wafer, a lower cladding layer, a core, and a second cladding composition layer in this order.

The composition layer for the second cladding of the intermediate laminate V is exposed to ultraviolet rays using a projection exposure device (Ushio Inc. "UFX-2240") with exposure energy such that the number of remaining gloss steps of the 41 step tablet is 8 steps. Exposure was performed. After exposure, ultraviolet rays were irradiated at 2 J/cm ² . The intermediate laminate V was placed in a clean oven, the temperature was raised from room temperature to 170°C, and after reaching 170°C, a heat treatment was performed for 60 minutes in a nitrogen atmosphere to harden the second cladding composition layer. . An upper cladding layer was formed by curing the second cladding composition layer, and a sample laminate including a silicon wafer, a lower cladding layer, a core, and an upper cladding layer was obtained.

In the obtained sample laminate, the combination of the lower cladding layer and the upper cladding layer constitutes the cladding layer. An optical waveguide was obtained that included a cladding layer and a core located in the cladding layer. In addition, in this sample stack, the cores have linear patterns with lengths of 1 cm, 2 cm, and 3 cm corresponding to the mask pattern that the quartz glass mask had, and the cores included in these patterns The width (line width) and interval (space) of the mask pattern matched the width (line width) and interval (space) of the mask pattern.

From the obtained sample laminate, the core and the surrounding cladding layer were cut out at the portion where the core was formed, to obtain a test substrate provided with an optical transmission path.

The obtained test board was placed on a vibration isolation table covered with a blackout curtain. A condensing module (numerical aperture 0.18) is connected to one end (incidence end) of the optical waveguide of the test board, and a light source (1310 nm light source, THORLABS Co., Ltd.) is connected to the condensing module via an optical fiber (input fiber). ``LPSC-1310-FC'') was connected. In addition, another light condensing module (numerical aperture 0.18) was connected to the other end (output end) of the optical waveguide of the test board, and a light receiver was connected to the light condensing module via an optical fiber (output fiber). (Optical power meter "N7742" manufactured by Keysight) was connected. Through the above operations, the light emitted from the light source passes through the optical fiber (input fiber), light collection module, optical waveguide, light collection module, and optical fiber (output fiber) in this order, and then enters the light receiver. I got the system. Hereinafter, this optical system may be referred to as a sample optical system. The light source was turned on and the intensity of the light that entered the light receiver was measured by the light receiver to measure the loss in the sample optical system.

The loss of the optical waveguide included in the test board was determined by subtracting the loss of the calibration optical system from the loss of the sample optical system.

The loss of the optical waveguide was measured for each of an optical waveguide with a length of 1 cm, an optical waveguide with a length of 2 cm, and an optical waveguide with a length of 3 cm. The measurement results were then plotted on a coordinate system with the length of the optical waveguide as the horizontal axis and the loss of the optical waveguide as the vertical axis, to obtain the loci of three points representing the measurement results. An approximate straight line at these three points was calculated using the least squares method, and the optical transmission loss (dB/cm) per unit distance of the optical waveguide was determined as the slope of the approximate straight line, and evaluated based on the following evaluation criteria.

"◎": Optical transmission loss less than 0.5 dB/cm "○": Optical transmission loss 0.5 dB/cm or more and less than 1.0 dB/cm "△": Optical transmission loss 1.0 dB/cm or more and 2.0 dB/cm Less than “×”: Optical transmission loss 2.0 dB/cm or more

The light receiver was removed, and an infrared camera (InGaAs camera with a 100x objective lens) was set in its place. The light source was turned on and the light emitted from the end of the optical fiber (output fiber) was photographed with an infrared camera. When only one perfectly circular edge of light was observed, it was determined to be single mode "S". Moreover, when a plurality of edges were observed, it was determined that the mode was multimode "M".

Table 1 below summarizes the amounts of raw materials used to produce the resin sheets with supports of Examples and Comparative Examples, the measurement results of the supports, and the evaluation results of Test Examples.

From the results shown in Table 1 above, the haze of the support is 10% or less, or the arithmetic mean roughness (Ra) of the contact surface with the resin composition layer of the support is 50 nm or less. It can be seen that by using a resin sheet with a support, it is possible to form an optical waveguide that has better core forming properties and suppresses optical transmission loss.

10 Optical waveguide 100 Core 110 Resin composition layer 110' Resin composition pattern 111 Exposed area 112 Non-exposed area 120 Support body 200 Clad layer 210 Composition layer for first clad 220 Lower clad layer 230 Composition layer for second clad 240 Upper cladding layer 300 Base material 400 Mask 410 Transparent part 420 Light shielding part

Claims (19)

A resin sheet with a support, comprising a support and a resin composition layer provided on the support,
The resin composition layer is a resin composition layer formed of a resin composition containing (A) an epoxy resin, (B) a photopolymerizable resin containing a carboxyl group, and (C) a photopolymerization initiator,
A resin sheet with a support for forming a core of an optical waveguide, which satisfies at least one of conditions (1) and (2).
Condition (1): The haze of the support measured according to JIS K6714 is 10% or less.
Condition (2): The arithmetic mean roughness (Ra) of the contact surface of the support with the resin composition layer is 50 nm or less. The resin sheet with a support according to claim 1, which satisfies condition (1). The resin sheet with a support according to claim 1, which satisfies both conditions (1) and (2). The resin sheet with a support according to claim 1, wherein the support is a polyethylene terephthalate film. The resin sheet with a support according to claim 1, wherein the thickness of the support is in the range of 10 μm to 50 μm. The resin sheet with a support according to claim 1, wherein the resin composition layer has a thickness in the range of 3 μm to 30 μm. The resin sheet with a support according to claim 1, wherein component (A) contains an epoxy resin having a naphthol aralkyl skeleton. The resin sheet with a support according to claim 1, wherein the component (B) contains a photopolymerizable resin containing an ethylenically unsaturated group and a carboxyl group. The resin sheet with a support according to claim 1, wherein the component (B) contains a photopolymerizable resin having a naphthol aralkyl skeleton. The resin sheet with a support according to claim 1, wherein the component (B) contains a carboxylic acid-modified epoxy (meth)acrylate resin. The resin sheet with a support according to claim 1, wherein the weight average molecular weight (Mw) of component (B) is 18,000 or less. The resin sheet with a support according to claim 1, wherein the molecular weight of component (C) is 400 or more. Component (C) comprises at least one photopolymerization initiator selected from an α-aminoketone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, and an oxime ester photopolymerization initiator. A resin sheet with a support as described. According to claim 1, the mass ratio of component (A) to component (B) in the resin composition forming the resin composition layer (component (A)/component (B)) is 0.1 to 3. Resin sheet with support. The support according to claim 1, wherein the mass ratio of component (B) to component (C) in the resin composition forming the resin composition layer (component (B)/component (C)) is 1 to 50. Resin sheet with body. The resin sheet with a support according to claim 1, wherein the resin composition forming the resin composition layer further contains (D) a reactive diluent. 17. The resin sheet with a support according to claim 16, wherein component (D) contains a difunctional or higher-functional (meth)acrylate compound that does not contain a carboxyl group. The resin sheet with a support according to claim 16, wherein the molecular weight of component (D) is 1,000 or less. (III) The resin sheet with a support according to any one of claims 1 to 18 is laminated on the lower cladding layer so that the resin composition layer is in contact with the lower cladding layer, and the resin composition layer is placed on the lower cladding layer. a step of forming the
(IV) a step of placing a mask on the support and subjecting a part of the resin composition layer to light exposure through the mask and the support;
(V) removing the mask and support;
(VI) forming a resin composition pattern by subjecting the resin composition layer to a development process;
(VII) curing the resin composition pattern to form a core on the lower cladding layer;
A method for manufacturing an optical waveguide, including in this order.

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