Epoxy Underfill Composition for High-Temperature Fillet Crack Resistance
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Solution Overview
Problem
The existing liquid epoxy resin sealing materials for semiconductor devices suffer from fillet cracks when exposed to high temperature aerobic conditions, leading to a loss of function and insufficient thermal cycle resistance.
Innovation Solution
Incorporating a hindered phenolic antioxidant with a specific structure into the liquid epoxy resin sealing material, comprising a liquid epoxy resin, an amine curing agent, and an inorganic filler, to suppress fillet cracks caused by aerobic thermal degradation, while maintaining excellent storage stability and thermal cycle resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid epoxy resin sealing material is used to seal the gap between the semiconductor element and the substrate, then the thermal cycle resistance is improved, but fillet cracks occur under high temperature aerobic conditions
Solution Approach 1:
A hindered phenolic antioxidant is introduced as an intermediary substance into the epoxy resin sealing material. This antioxidant mediates between the epoxy resin matrix and the harmful aerobic thermal degradation, preventing fillet cracks by scavenging free radicals generated during high temperature storage. The antioxidant acts as a protective intermediary that sacrifices itself to prevent degradation of the structural components.
Solution Approach 2:
The chemical composition parameters of the sealing material are changed by adding specific antioxidants (e.g., Irgafos 168, Irganox 1010, Irganox 1035, Irganox 1076) at controlled concentrations (0.01-5 wt%). This parameter change modifies the material's resistance to aerobic thermal degradation, enabling it to maintain structural integrity under high temperature storage conditions while preserving its sealing function.
2Reliability
If inorganic filler is added to improve moisture resistance and thermal cycle resistance, then the thermal expansion coefficient difference is controlled, but the material becomes more susceptible to aerobic thermal degradation
Solution Approach 1:
The sealing material is designed as a composite system combining epoxy resin, inorganic filler (e.g., silica, alumina), and hindered phenolic antioxidant. This composite structure leverages the advantages of each component: the inorganic filler provides thermal stability and controlled thermal expansion, while the antioxidant component specifically addresses aerobic thermal degradation. The synergistic combination resolves the contradiction by protecting the composite material as a whole.
Solution Approach 2:
The antioxidant is distributed throughout the sealing material matrix to provide localized protection against aerobic thermal degradation. This local quality enhancement ensures that even in regions with high inorganic filler content (which may create stress concentration points), the antioxidant is present to prevent crack initiation and propagation under thermal stress.
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 effectively suppresses fillet cracks under high temperature aerobic conditions and ensures good storage stability at room temperature, with a reduced number of cracks and improved pot life, making it suitable for use as an underfill material in semiconductor devices.
Implementation Method 1
a hindered phenolic antioxidant having a free radical scavenging action
Implementation Method 2
the underfill material is injected into the gap between the two by capillary action
Implementation Method 3
By heat-curing the underfill material after injection of the underfill material, it is possible to reinforce a connection between the two
Data Source
AI summary
Provided are a liquid epoxy resin sealing material capable of suppressing occurrence of fillet cracks generated when an underfill cured product is left under high temperature aerobic conditions, and a semiconductor device using the liquid epoxy resin sealing material. More specifically, provided are the liquid epoxy resin sealing material containing (A) a liquid epoxy resin, (B) an amine curing agent, (C) an inorganic filler and (D) an antioxidant agent represented by the following formula, wherein 0.5 to 10 parts by mass of (D) the antioxidant agent is contained based on a total of 100 parts by mass of (A) the epoxy resin and (B) the amine curing agent, and the semiconductor device using the liquid epoxy resin sealing material.