Curable Particulate Silicone Composition for Low Thermal Expansion
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Solution Overview
Problem
Current curable silicone compositions for overmold molding lack sufficient hardness and toughness at high temperatures, with average linear expansion coefficients exceeding 15 ppm/°C, and existing technologies struggle to achieve both low expansion coefficients and mechanical strength in semiconductor applications.
Innovation Solution
A curable particulate silicone composition comprising hot-melt silicone fine particles with hydrosilylation or radical reactive groups, combined with an inorganic filler treated with a silicone-based surface agent, providing a cured product with an average linear expansion coefficient of not greater than 15 ppm/°C and enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional curable silicone compositions are used for overmold molding, then handling workability is improved, but the average linear expansion coefficient exceeds 15 ppm/°C and mechanical strength is insufficient at high temperatures
Solution Approach 1:
The patent uses a composite material system consisting of organopolysiloxane base polymer, inorganic filler (such as silica), and specific curing agents. This composite approach allows simultaneous achievement of low linear expansion coefficient (≤15 ppm/°C) and good handling workability by combining materials with complementary properties.
Solution Approach 2:
The patent optimizes specific parameters including the ratio of crosslinking agents, particle size distribution of inorganic fillers (0.1-10 μm), and chemical composition of the polysiloxane. By carefully controlling these parameters, the composition achieves both low thermal expansion and adequate mechanical properties for semiconductor applications.
2Ease of operation
If conventional curable silicone compositions are used for overmold molding, then handling workability is improved, but hardness and toughness are insufficient at high temperatures up to 250°C
Solution Approach 1:
The patent incorporates inorganic fillers (silica, alumina, or titania) with specific particle sizes (0.1-10 μm) into the silicone composition. This composite structure provides reinforcement that maintains hardness and toughness at high temperatures up to 250°C while preserving the handling workability of the uncured material.
Solution Approach 2:
The patent creates local reinforcement by distributing inorganic filler particles throughout the silicone matrix. The filler particles provide localized strength and thermal stability, while the silicone matrix maintains overall flexibility and handling properties. This local quality enhancement allows the material to exhibit different properties at different scales.
3Reliability
If liquid or pasty curable silicone compositions with low linear expansion coefficient are used, then average linear expansion coefficient is improved, but mechanical strength is insufficient causing warp or breakage
Solution Approach 1:
The patent creates a composite system where inorganic filler particles (0.1-10 μm) are dispersed in the liquid or pasty silicone composition. This composite structure provides the mechanical strength needed to prevent warping and breakage while maintaining the low linear expansion coefficient characteristic of silicone materials.
Solution Approach 2:
The inorganic filler acts as an intermediary that transfers and distributes mechanical stresses throughout the material. This intermediary structure prevents stress concentration that would lead to warping or breakage, while the silicone matrix continues to provide low thermal expansion properties.
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 excellent handling workability and curing characteristics, resulting in a cured product with improved hardness and toughness from room temperature to 250°C, suitable for semiconductor devices and power semiconductor applications.
Implementation Method 1
an inorganic filler (fine particles); and wherein component (B) is treated with a silicone-based surface treatment agent
Implementation Method 2
curable particulate silicone composition which provides a cured product having a very low average linear expansion coefficient
Data Source
AI summary
A curable particulate silicone composition is disclosed. The composition comprises: (A) hot-melt silicone fine particles having a specific reactive functional group; (B) an inorganic filler; and (C) a curing agent. The content of component (B) is in the range of from 87 to 95 vol. % of the total composition. The curable particulate silicone composition provides a cured product having an average linear expansion coefficient of not greater than 15 ppm/° C. in a range of from 25° C. to 200° C. The curable particulate silicone composition provides a cured product having a very low average linear expansion coefficient over a wide temperature range when cured and is particularly suitable for overmold molding and the like.