Modified Epoxy Resin for Semiconductor Packaging
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Solution Overview
Problem
Semiconductor packaging materials face challenges with asymmetrical thermal expansion leading to bending issues, thin package molding defects, and reliability concerns due to high reflow temperatures in lead-free soldering processes, particularly in BGA, BOC, and MCP designs, requiring materials with flame retardance, bending resistance, and moldability without halogen or phosphorus-based additives.
Innovation Solution
An epoxy resin composition comprising a modified epoxy resin from glycidyl etherification of a novolac type phenolic compound with a biphenyl derivative, combined with a polyfunctional curing agent and inorganic fillers like fused silica, which provides high flame retardance, bending resistance, and moldability in thin packages, while being compatible with advanced reflow processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional packaging materials are used in BGA-type packages, then the package structure is simple, but the package bends due to asymmetrical coefficient of linear thermal expansion
Solution Approach 1:
The patent modifies the chemical composition parameters of the epoxy resin by incorporating specific phenolic compounds with controlled molecular structures (represented by formulas with variable n values from 1 to 6). This chemical parameter change adjusts the coefficient of linear thermal expansion to achieve better thermal-mechanical stability and reduce package bending while maintaining structural integrity
Solution Approach 2:
The patent creates a composite epoxy resin system by combining epoxy resin with specific phenolic compounds and curing agents. This composite material approach integrates multiple components with complementary properties to simultaneously achieve flame retardance, bending resistance, and moldability in thin packages
2Length of stationary object
If the thickness of packaging materials is decreased to roughly one hundred microns, then the package design is more advanced, but molding defects such as voids and incomplete molding occur frequently
Solution Approach 1:
The patent adjusts the rheological and viscosity parameters of the epoxy resin composition by selecting specific phenolic compounds with appropriate molecular weights and structures. These parameter changes enable the resin to maintain optimal flow characteristics during molding of thin packages (around 100 microns thick), ensuring complete filling and void-free molding while preserving the advanced thin-package design
Solution Approach 2:
The patent enhances the local quality of the epoxy resin by incorporating phenolic compounds with specific structural features that improve wetting and adhesion properties. This localized quality enhancement ensures uniform distribution and complete penetration through the thin package structure, preventing molding defects in critical thin regions
3Reliability
If lead-free soldering processes with higher melting point materials are used, then environmental compliance is improved, but reflow temperatures increase which degrades package reliability
Solution Approach 1:
The patent converts the harmful effect of high reflow temperatures into a beneficial opportunity by selecting phenolic compounds and curing agents that form thermally stable crosslinked networks. The high temperature exposure during lead-free soldering actually enhances the curing and crosslinking density of the epoxy resin, improving package reliability and thermal stability while maintaining environmental compliance
Solution Approach 2:
The patent modifies the thermal stability parameters of the packaging material by incorporating phenolic compounds with high thermal resistance and stable aromatic structures. These parameter changes raise the glass transition temperature and thermal decomposition point of the epoxy resin, enabling it to withstand higher reflow temperatures associated with lead-free soldering processes without degrading package reliability
4Object-affected harmful factors
If halogen-type or phosphorus-type flame retardants are used, then flame retardance is improved, but environmental and health concerns increase
Solution Approach 1:
The patent extracts and eliminates halogen-type and phosphorus-type flame retardants from the packaging material composition. Instead, it incorporates phenolic compounds that provide inherent flame retardant properties through their aromatic structures and char-forming capabilities during combustion, thereby removing harmful substances while maintaining effective flame retardance
Solution Approach 2:
The patent enables the epoxy resin system to provide its own flame retardant protection through the inherent properties of phenolic compounds. These compounds promote char formation and heat dissipation during combustion without requiring external flame retardant additives, making the material self-protecting against fire while avoiding environmental and health hazards associated with conventional flame retardants
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 epoxy resin composition effectively enhances the reliability of semiconductor packages by providing superior flame retardance, bending resistance, and moldability, ensuring the integrity and performance of semiconductor devices under various thermal and environmental conditions without using halogen or phosphorus-based flame retardants.
Implementation Method 1
the epoxy resin is a modified epoxy resin prepared by glycidyl etherification of a mixture of a novolac type phenolic compound having a biphenyl derivative in the molecule
Implementation Method 2
they tend to bend due to an asymmetrical coefficient of linear thermal expansion
Implementation Method 3
the curing agent is a mixture of the novolac type phenolic compound having a biphenyl derivative in the molecule and a polyfunctional curing agent
Data Source
AI summary
An epoxy resin composition, and a method of making the same, includes an epoxy resin and a curing agent, the epoxy resin composition also includes inorganic fillers, curing accelerators, and modified silicone oils. The epoxy resin is a modified epoxy resin prepared by glycidyl etherification of a mixture of a novolac type phenolic compound having a biphenyl derivative in the molecule and a 4,4′-dihydroxy biphenyl compound, and the curing agent is a mixture of a polyaromatic curing agent and a polyfunctional curing agent.