Power Module Encapsulation Resin for Low Viscosity and Crack Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing encapsulating materials for power semiconductor elements face issues with high viscosity, sedimentation of inorganic fillers, and increased likelihood of cracks due to thermal expansion, which compromise the reliability and performance of the encapsulating resin.
Innovation Solution
A liquid resin composition comprising an alicyclic epoxy resin, acid anhydride, curing accelerator, inorganic filler, and sedimentation preventing agent, with specific ratios and additives to maintain low viscosity and prevent filler sedimentation, resulting in a cured product with excellent heat resistance and crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If inorganic filler is added to reduce linear expansion coefficient, then heat resistance is improved, but viscosity increases and workability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the epoxy resin system by selecting specific epoxy resins with appropriate viscosity and reactivity, and adjusting the curing agent ratio, to achieve low viscosity (75 Pa·s or less) while maintaining heat resistance through the inorganic filler content (65-85% by mass of total solid content)
Solution Approach 2:
The patent creates a composite material system combining epoxy resin, acid anhydride curing agent, and inorganic filler in specific proportions, where the organic resin matrix provides workability and the inorganic filler provides heat resistance, achieving both requirements simultaneously
2Temperature
If inorganic filler is added to reduce linear expansion coefficient, then heat resistance is improved, but filler settles during curing and causes cracks
Solution Approach 1:
The patent introduces a sedimentation preventing agent as an intermediary substance that acts between the inorganic filler and the epoxy resin matrix, preventing filler particles from settling during storage and curing by providing steric or electrostatic repulsion, thereby maintaining uniform distribution and preventing cracks
Solution Approach 2:
The patent optimizes the particle size distribution and surface treatment of the inorganic filler to change its physical parameters, reducing its tendency to settle while maintaining the desired linear expansion coefficient and heat resistance properties
3Stability of the object's composition
If inorganic filler content is increased to reduce linear expansion, then thermal stability is improved, but viscosity increases and casting workability deteriorates
Solution Approach 1:
The patent carefully controls the viscosity parameter of the liquid resin composition by selecting epoxy resins with appropriate molecular weight and structure, and by optimizing the total solid content and inorganic filler content ratio, achieving viscosity of 75 Pa·s or less while maintaining low linear expansion coefficient through sufficient inorganic filler content (65-85% by mass)
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 ensures excellent workability during casting, reduces filler sedimentation, and provides a cured product with superior mechanical, electrical, and thermal properties, enhancing the reliability of power devices.
Implementation Method 1
the liquid resin composition containing: (A) an epoxy resin; (B) an acid anhydride; (C) a curing accelerator; (D) an inorganic filler; and (E) a sedimentation preventing agent
Implementation Method 2
a sedimentation preventing agent... reduces sedimentation of the inorganic filler during storage
Data Source
AI summary
Provided is a liquid resin composition used for encapsulating, by a casting method, a power module which includes a substrate for a power module, over which a circuit layer is formed, and a power semiconductor element mounted over the circuit layer of the substrate for a power module, the liquid resin composition containing (A) an epoxy resin, (B) an acid anhydride, (C) a curing accelerator, (D) an inorganic filler, and (E) a sedimentation preventing agent, in which the epoxy resin (A) includes an alicyclic epoxy resin, and a viscosity of the liquid resin composition at 25° C. is 75 Pa·s or less.