Reactive Filler Adhesive for Semiconductor Wire Bonding
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Solution Overview
Problem
Existing adhesive compositions for semiconductor devices face challenges in uniformly mixing fillers, leading to aggregation and reduced adhesive layer thickness and adhesiveness, especially during simultaneous curing processes, which can result in inaccurate wire bonding and decreased packaging reliability due to partial curing and increased stress from high mounting temperatures.
Innovation Solution
An adhesive composition comprising an acrylic polymer, a heat curable resin with unsaturated hydrocarbon groups, and a filler with reactive double bonds, such as silica, which allows for uniform filler dispersion and maintains adhesive layer hardness before curing, enabling stable wire bonding and enhanced adhesiveness between semiconductor chips and circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a relatively large amount of filler is blended in the adhesive agent to make it harder before curing, then the adhesive layer hardness before curing is improved, but the filler dispersibility deteriorates leading to aggregation and reduced adhesive layer thickness accuracy
Solution Approach 1:
The invention changes the chemical parameters of the filler by introducing reactive double bonds on the filler surface. This chemical modification allows the filler to react with the curable component during curing, preventing aggregation and improving dispersibility while maintaining the desired hardness and thickness accuracy of the adhesive layer.
Solution Approach 2:
The invention creates a composite material system where the filler with reactive double bonds is integrated into the curable component matrix. This composite structure ensures uniform distribution of filler particles throughout the adhesive layer, preventing aggregation and maintaining both hardness and thickness precision.
2Productivity
If simultaneous curing of the adhesive layer is applied after all chips are stacked, then the production efficiency is improved by omitting intermediate curing steps, but the wire bonding accuracy deteriorates due to chip vibration and displacement
Solution Approach 1:
The invention performs preliminary hardening of the adhesive layer before wire bonding by utilizing the reactivity of the double bonds. This preliminary action provides sufficient mechanical stability during wire bonding while allowing the curing process to be completed simultaneously after stacking, thus maintaining both precision and productivity.
Solution Approach 2:
The invention changes the physical state of the adhesive layer through controlled chemical reactions of the double bonds with the curable component. This parameter change enables the adhesive to provide appropriate hardness at different stages: softer during stacking for ease of operation, and harder during wire bonding for stability, resolving the contradiction between productivity and precision.
3Productivity
If the adhesive layer is not cured or only semi-cured during wire bonding, then the simultaneous curing method can be applied to improve productivity, but the chip stability deteriorates causing vibration and displacement
Solution Approach 1:
The invention applies preliminary hardening action through the chemical reactivity of the double bonds on the filler surface. This preliminary action occurs before wire bonding, providing sufficient chip stability to prevent vibration and displacement, while the complete curing process is finalized simultaneously after stacking to maintain high productivity.
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 solution ensures stable wire bonding and improved packaging reliability by maintaining adhesive layer hardness and adhesiveness, even under high temperature conditions, thereby enhancing the production efficiency and reliability of semiconductor devices in multistacked packages.
Implementation Method 1
a filler (C) having reactive double bond on a surface
Implementation Method 2
a heat curable resin (B) having unsaturated hydrocarbon group
Data Source
AI summary
An adhesive composition includes an acrylic polymer (A), a heat curable resin (B) having unsaturated hydrocarbon group, and a filler (C) having reactive double bond on a surface.