Metallic Foam Clip Structure for Semiconductor Stress Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor assemblies face delamination due to internal stresses caused by differing coefficients of thermal expansion among components, leading to potential failure, especially in temperature fluctuating environments.
Innovation Solution
A clip for semiconductor devices is formed from metallic foam, which absorbs stress and improves adhesion with an isolator, reducing delamination risks, and is secured using tin metallic layers with high melting temperatures to prevent joint melting and ensure reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid copper clips are used, then electrical conductivity is maintained, but the clip cannot absorb thermal expansion stresses leading to delamination
Solution Approach 1:
The clip is formed from metallic foam with a porous structure that allows it to absorb and dissipate thermal expansion stresses through deformation of the foam matrix, preventing stress concentration that would cause delamination while maintaining structural integrity
Solution Approach 2:
The invention uses metallic foam as a composite material that combines the conductivity of metal with the stress-absorbing characteristics of foam structure, creating a material that simultaneously provides electrical conductivity and stress absorption capability
2Reliability
If the clip is made more flexible to absorb stress, then delamination is reduced, but electrical conductivity decreases
Solution Approach 1:
The invention optimizes parameters including pore size (10-100μm), porosity (30-80%), and cell structure of the metallic foam to achieve the optimal balance between flexibility for stress absorption and electrical conductivity for functional performance
3Reliability
If the isolator is applied to cover the clip, then protection is provided, but adhesion is insufficient causing separation
Solution Approach 1:
The porous structure of the metallic foam allows the isolator material to penetrate and adhere to the internal surface area of the foam, creating mechanical interlocking that significantly enhances adhesion strength without requiring additional complex manufacturing steps
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 metallic foam clip effectively reduces internal stresses and enhances adhesion, minimizing delamination and increasing the reliability of semiconductor devices by optimizing conductivity and flexibility, while the high-melting tin joints prevent short circuits and current leakage.
Implementation Method 1
Since at least part of the clip is formed from a metallic foam, the clip is able to better absorb the stresses that it is subject to in use
Implementation Method 2
The clip being formed of a foam improves adhesion between the clip and the isolator because the isolator enters the holes defined by the foam, which provides a greater contact area between the isolator and the clip
Implementation Method 3
providing a first metallic layer to the semi-conductor die and providing a second metallic layer to the lead portion; heating the clip, the first metallic layer, and the second metallic layer such that the first metallic layer and the second metallic layer melt
Data Source
Figure 1
Figure 2
Figure 3
AI summary
There is disclosed a clip for a semi-conductor device. At least part of the clip is formed from a metallic foam.