Sintered Silver Bonding for Dissimilar Semiconductor Materials
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Solution Overview
Problem
Semiconductor device packages incorporating ceramic, organic, and metallic materials face failures due to differing material properties, such as coefficient of thermal expansion, leading to issues like warping and cracking, especially during high-temperature processing.
Innovation Solution
The use of nano-scale silver particles applied under pressure at low temperatures (around 250°C) to form a solid silver interface between these materials, reducing the effects of thermal expansion mismatches and enhancing bonding, thermal, and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature processing is used to bond ceramic, organic, and metallic materials, then bonding strength is improved, but material failures occur due to thermal expansion mismatches causing warping and cracking
Solution Approach 1:
The patent changes the bonding temperature parameter from conventional high temperatures to low temperatures (around 250°C). This parameter change allows bonding of ceramic, organic, and metallic materials without causing thermal expansion mismatches that lead to warping and cracking, thereby maintaining bonding strength while improving package reliability
Solution Approach 2:
The patent introduces sintered silver as an intermediary bonding material between the ceramic, organic, and metallic materials. The sintered silver acts as a compliant layer that accommodates thermal expansion differences, enabling reliable bonding of dissimilar materials at low temperatures without direct high-temperature contact between the materials
2Strength
If conventional bonding materials are used to join dissimilar materials, then bonding is achieved, but thermal and electrical conductivity are reduced
Solution Approach 1:
The patent changes the material composition parameter by using sintered silver instead of conventional bonding materials. Sintered silver provides both bonding capability and high thermal and electrical conductivity, eliminating the trade-off between bonding strength and conductivity that exists with conventional bonding materials
Solution Approach 2:
The patent uses sintered silver, which is a composite structure of silver particles bonded together, as the bonding material. This composite material provides both the mechanical bonding function and the high thermal/electrical conductivity required, unlike conventional bonding materials that sacrifice conductivity for bonding capability
3Reliability
If expensive materials like laminates or alloys are used, then material compatibility is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses sintered silver as an intermediary that enables compatibility between dissimilar materials (ceramic, organic, metallic) without requiring expensive laminates or alloys. The sintered silver provides a compliant interface that accommodates thermal expansion differences, achieving material compatibility at lower cost
Solution Approach 2:
The patent replaces expensive materials like laminates or alloys with a more economical sintered silver bonding layer. The sintered silver provides the necessary compatibility and bonding functions at lower material cost, making the overall package more cost-effective while maintaining reliability
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
This approach allows for the creation of high-temperature and high-performance semiconductor packages that are more reliable, cost-effective, and thermally conductive, using less expensive materials like solid copper instead of laminates or alloys, while avoiding material failures and improving electrical conductivity.
Implementation Method 1
The silver is applied in the form of fine particles (e.g., nano particle silver) under pressure and a low temperature (e.g., sintering at 250° C.)
Implementation Method 2
the effect of differing material properties between ceramic, organic, and metallic components, such as coefficient of thermal expansion, is reduced due to low temperature of bonding and the ductility of the silver
Implementation Method 3
provides a path for thermal conduction away from semiconductor devices housed within the package
Implementation Method 4
provides a path for thermal conduction away from semiconductor devices housed within the package and also provides a path for electrical conduction across the package
Data Source
AI summary
A semiconductor device package that incorporates a combination of ceramic, organic, and metallic materials that are coupled using silver is provided. The silver is applied in the form of fine particles under pressure and a low temperature. After application, the silver forms a solid that has a typical melting point of silver, and therefore the finished package can withstand temperatures significantly higher than the manufacturing temperature. Further, since the silver is an interfacial material between the various combined materials, the effect of differing material properties between ceramic, organic, and metallic components, such as coefficient of thermal expansion, is reduced due to low temperature of bonding and the ductility of the silver.