Photocurable Resin Composition for Printed Wiring Boards
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Solution Overview
Problem
Photocurable resin compositions used for printed wiring boards face challenges in achieving a balance between heat resistance and brittleness, with existing solutions compromising on sensitivity, alkali developability, and reliability in terms of water resistance and electrical insulating properties.
Innovation Solution
A photocurable resin composition incorporating a carboxyl group-containing resin, a photopolymerization initiator, a vinyl group-containing elastomer, and a styryl group-containing compound, along with a mercapto compound, to enhance sensitivity, alkali developability, and resistance to non-electrolysis gold plating, while maintaining flexibility and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the crosslinking density is increased by using polyfunctional epoxy resin or (meth)acrylate, then heat resistance and dimension stability are improved, but the cured product becomes brittle
Solution Approach 1:
The patent uses a composite resin system combining carboxyl group-containing epoxy (meth)acrylate with vinyl group-containing elastomer and styryl group-containing compound. This composite approach allows the cured product to achieve both heat resistance from the epoxy component and flexibility from the elastomer component, resolving the contradiction between heat resistance and brittleness.
Solution Approach 2:
The patent introduces specific functional groups (vinyl groups in elastomer, styryl groups) that can undergo crosslinking reactions to control the crosslinking density and network structure. By adjusting the composition ratios and curing conditions, the patent optimizes the balance between heat resistance and flexibility.
2Measurement precision
If a polymer compound with radical polymerizable vinyl group in side chain is used to achieve high-speed curing and improved sensitivity, then sensitivity is improved, but compatibility with alkali developability deteriorates
Solution Approach 1:
The patent introduces carboxyl groups at specific locations in the resin molecule (from carboxyl group-containing epoxy (meth)acrylate) that provide alkali developability, while other parts of the molecule (vinyl groups in elastomer) provide sensitivity. This local differentiation allows both properties to coexist without mutual interference.
Solution Approach 2:
The styryl group-containing compound acts as an intermediary that facilitates crosslinking and enhances sensitivity while being compatible with the alkali developability provided by the carboxyl group-containing epoxy (meth)acrylate.
3Strength
If a mixture of bisphenol type and Novolac type carboxyl group-containing epoxy (meth)acrylate is used to improve flexibility, then brittleness is reduced, but dimension stability and water resistance cannot be obtained at sufficient level
Solution Approach 1:
The patent creates a composite system combining carboxyl group-containing epoxy (meth)acrylate with vinyl group-containing elastomer and styryl group-containing compound. This multi-component composite approach allows simultaneous achievement of flexibility (from elastomer), dimension stability (from crosslinked network), and water resistance (from hydrophobic groups) that cannot be obtained with simple binary mixtures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves high sensitivity and alkali developability, producing a cured product with improved resistance to heat, water, and electrical insulating properties, maintaining flexibility and crack resistance without compromising migration resistance.
Implementation Method 1
a photocurable resin composition includes a solvent development type and an alkali development type... a photocurable resin composition can be used for microfabrication by applying the principles of photography (photolithography)
Data Source
AI summary
Provided is a photocurable resin composition, which has sensitivity equal to or greater than existing compositions, has alkali development properties, and which produces a cured product that does not become brittle with changes in temperature, and which also has excellent reliability in terms of water resistance, electrical insulating properties, PCT resistance, and the like. The photocurable resin composition comprises a carboxyl group-containing resin, a photopolymerization initiator, a vinyl group-containing elastomer, and a styryl group-containing compound.