Naphthalene Epoxy Resin for Semiconductor Encapsulation
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Solution Overview
Problem
Current epoxy resin compositions for semiconductor encapsulation face challenges with warpage, delamination, and moisture absorption issues during lead-free soldering, particularly in high-density packages like BGA and QFN, due to increased crosslink density and viscosity, which compromise flow and crack resistance.
Innovation Solution
An epoxy resin composition combining a naphthalene ring-containing epoxy resin with a phenolic resin and an inorganic filler, optimized to achieve a balance of flowability, low coefficient of linear expansion, high glass transition temperature, minimal moisture absorption, and improved crack resistance, by controlling the weight percentage of naphthalene rings and epoxy equivalent in the resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If crosslink density of resin is increased to elevate glass transition temperature, then heat resistance is improved, but moisture absorption increases and delamination occurs at interfaces
Solution Approach 1:
The patent changes the chemical composition parameters of the epoxy resin by incorporating naphthalene ring structures (specifically 1,1-bis(2,7-diglycidyloxy-1-naphthyl)alkane) to achieve high glass transition temperature while maintaining low moisture absorption and good adhesion properties
Solution Approach 2:
The patent creates a composite epoxy resin system combining naphthalene ring-containing epoxy resin with specific curing agents and inorganic fillers to achieve multiple properties simultaneously: high Tg, low moisture absorption, and good interface adhesion
2Reliability
If more inorganic filler is loaded to provide low water absorption and low coefficient of expansion, then moisture resistance is improved, but viscosity increases and flow during molding is compromised
Solution Approach 1:
The patent optimizes the particle size distribution and composition of inorganic fillers (such as silica) to maintain low viscosity while achieving low moisture absorption and low coefficient of thermal expansion in the cured resin
Solution Approach 2:
The patent applies surface treatment to inorganic filler particles to improve their dispersion and compatibility with the epoxy resin matrix, reducing viscosity increase while maintaining moisture resistance
3Strength
If resin modulus at high temperature is increased to improve reflow resistance, then soldering resistance is improved, but crack resistance upon lead-free soldering deteriorates
Solution Approach 1:
The patent modifies the resin's viscoelastic properties by incorporating naphthalene ring-containing epoxy resin that maintains appropriate modulus at high temperature while preserving crack resistance through its molecular structure
Data Source
AI summary
An epoxy resin composition comprising(A) at least one epoxy resin comprising (a) a naphthalene ring-containing epoxy resin having at least one substituted or unsubstituted naphthalene ring in a molecule and having an epoxy equivalent of 175 to 210,(B) a phenolic resin having at least one substituted or unsubstituted naphthalene ring in a molecule, and(C) an inorganic filler,the substituted or unsubstituted naphthalene ring of the epoxy resin (a) being contained in an amount of 45 to 60% by weight in the total amount of the epoxy resin (A) is best suited for semiconductor encapsulation because it has good flow, a low coefficient of linear expansion, a high Tg, minimal moisture absorption, and crack resistance upon lead-free soldering.