Curable Resin Composition Foaming Prevention
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Solution Overview
Problem
Conventional encapsulant materials for power semiconductor elements, such as epoxy and silicone resin compositions, face challenges in achieving sufficient heat resistance and preventing foaming during curing, which limits their application in high-temperature environments like those required for SiC and GaN semiconductor devices.
Innovation Solution
A curable resin composition comprising a polysiloxane compound with specific functional groups and silica with a pH of 6.1 or lower, used in a ratio of 70 to 97 mass %, which suppresses foaming and provides high heat resistance, suitable for forming encapsulants in various shapes and sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If condensation type polysiloxane compounds are used for curing, then heat resistance is improved, but foaming occurs due to gas generation
Solution Approach 1:
The patent converts the harmful gas byproducts of condensation curing into beneficial effects by adding silica particles that act as gas traps and nucleation sites. The silica absorbs and immobilizes the gas molecules, preventing foaming while maintaining the heat-resistant properties of the condensation-cured polysiloxane network.
Solution Approach 2:
Silica serves as an intermediary substance between the polysiloxane matrix and the gas byproducts. It mediates the interaction by providing surfaces for gas adsorption and creating a physical barrier that prevents gas coalescence into foam bubbles, thus resolving the contradiction between using condensation curing for heat resistance and avoiding foaming.
2Strength
If epoxy resin compositions are used, then mechanical strength is maintained, but heat resistance deteriorates at temperatures above 150°C
Solution Approach 1:
The patent creates a composite material system combining polysiloxane (for heat resistance) with silica fillers (for structural support and foaming suppression). This composite approach allows the material to achieve both high-temperature stability and maintained mechanical strength, overcoming the limitations of pure epoxy resin which deteriorates above 150°C.
3Temperature
If silicone resin compositions are used, then heat resistance is improved, but cross-linkage thermal stability is poor
Solution Approach 1:
The patent changes the chemical parameters of the silicone resin system by selecting specific polysiloxane compounds with controlled functional groups and adjusting the silica content and particle size distribution. These parameter changes optimize both the heat resistance and the thermal stability of cross-linkages, creating a more stable cured product network.
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 curable resin composition effectively prevents foaming during curing and achieves high heat resistance, making it suitable for encapsulating power semiconductor elements, especially those requiring high-temperature performance like SiC and GaN devices.
Implementation Method 1
component (B): silica whose extract water has a pH of 6.1 or lower at 25° C.
Implementation Method 2
a method using so-called condensation and, more specifically, at least one of dehydration condensation between silanol groups, dealcoholization condensation between a silanol group and an alkoxysilyl group and dehydrocondensation of a silanol group and a hydrosilyl group
Data Source
AI summary
According to one aspect of the present invention, there is provided a curable resin composition including at least: a polysiloxane compound having, in a molecule thereof, at least two functional groups selected from the group consisting of silanol groups and alkoxysilyl groups as a component (A-1); and silica whose extract water has a pH of 6.1 or lower at 25° C. as a component (B), wherein the amount of the component (B) relative to the total amount of the components (A-1) and (B) is in a range of 70 to 97 mass %. This curable resin composition is able to, even when formed into various shapes and sizes, prevent foaming during curing and thus is suitable as an encapsulant material for a semiconductor element.