Silver-Gold Bonding Layer for Heat-Resistant Semiconductor Modules
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Solution Overview
Problem
Power semiconductor modules using solder as a bonding material face challenges with heat resistance as operating temperature increases, leading to potential oxidation, embrittlement, and reliability issues due to voids in the bonding layer.
Innovation Solution
A bonding layer comprising silver nanoparticles with a gold region between them is used, which is formed by applying a silver nano paste and heat-treating it, allowing gold atoms to diffuse and cover the voids, reducing reactivity and enhancing bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solder is used as a bonding material, then the bonding process is simple and cost-effective, but the heat resistance deteriorates at high operating temperatures leading to oxidation and embrittlement
Solution Approach 1:
The patent changes the material composition parameters by incorporating gold atoms into the silver nano paste bonding material. This compositional modification enables the bonding layer to maintain low electrical resistance and high reliability at elevated temperatures up to 150°C, resolving the heat resistance issue while preserving the simplicity of the bonding process.
Solution Approach 2:
The patent creates a composite bonding material by combining silver nanoparticles with gold atoms. This composite structure leverages the high electrical conductivity of silver while incorporating gold's superior heat resistance and oxidation resistance, thereby achieving both electrical performance and thermal stability in a single bonding layer.
2Reliability
If silver nano paste is used to improve heat resistance, then the melting point increases, but voids form during bonding leading to oxidation and embrittlement
Solution Approach 1:
The patent uses gold atoms as an intermediary substance that fills the voids formed during the silver nano paste bonding process. These gold atoms act as a mediating element that prevents direct exposure of the silver particles to oxygen, thereby preventing oxidation and embrittlement while maintaining the heat resistance benefits of the silver-based bonding material.
Solution Approach 2:
The patent applies preliminary anti-action by having gold atoms pre-positioned to fill voids before oxidation can occur. This preventive measure counteracts the harmful effect of void formation by eliminating the pathways through which oxygen would penetrate and cause oxidation, thereby protecting the bonding layer's integrity at high temperatures.
3Device complexity
If voids are present in the bonding layer, then the bonding structure is simpler, but electrical resistance increases and reliability decreases
Solution Approach 1:
The patent applies the taking out principle by extracting or removing the harmful voids from the bonding layer structure through the incorporation of gold atoms. The gold atoms occupy the void spaces, effectively eliminating them and creating a more continuous, reliable bonding pathway that maintains low electrical resistance while preserving the overall simplicity of the bonding layer design.
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 improves the reliability of power semiconductor modules by preventing oxidation, reducing electromigration, and maintaining low electrical resistance, thus enhancing the module's performance and longevity.
Implementation Method 1
gold atoms to diffuse and cover the voids
Implementation Method 2
by evaporating the solvent by heating
Data Source
AI summary
A semiconductor device according to an embodiment includes a semiconductor layer, a metal layer, and a bonding layer provided between the semiconductor layer and the metal layer, the bonding layer including a plurality of silver particles, and the bonding layer including a region containing gold existing between the plurality of silver particles.