Glass-Ceramic Package for High-Temperature Hermetic Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor packaging technologies fail to provide hermetically sealed packages capable of withstanding high assembly and operating temperatures, especially for high-temperature semiconductors like silicon carbide, gallium arsenide, and diamond, due to the limitations of thermoplastic epoxy encapsulants and thermal mismatch between components.
Innovation Solution
A non-cavity, molded glass/ceramic package with a thermal coefficient of expansion less than 5.0×10−6 and a glass transition temperature greater than 450°C is developed, using metal brazes for connections and a glass ceramic compound that chemically bonds with components to create a hermetic seal, allowing the package to operate between 300-400°C and withstand extreme temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic epoxy encapsulants are used to seal packages, then manufacturing cost is reduced and ease of manufacture is improved, but the package cannot withstand high operating temperatures above 200°C and cannot provide hermetic sealing
Solution Approach 1:
The patent changes the material parameters by replacing thermoplastic epoxy with a glass-ceramic compound that has a glass transition temperature greater than 450°C and specific coefficient of thermal expansion properties, enabling the package to withstand high operating temperatures while maintaining hermetic sealing
Solution Approach 2:
The patent uses a composite glass-ceramic compound that combines the benefits of glass (hermetic sealing, high temperature resistance) and ceramic (thermal stability, low CTE), creating a material that simultaneously provides hermetic sealing and high temperature capability
2Reliability
If glass ceramic compound is used for hermetic sealing at high temperatures, then temperature resistance and hermetic sealing are improved, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical assembly processes with a chemical bonding approach where the glass-ceramic compound chemically bonds to metal surfaces during a single heating cycle, simplifying the manufacturing process while achieving hermetic sealing
3Ease of manufacture
If aluminum wire bonding is used for electrical interconnections, then ease of manufacture is improved, but the wire melts into the die at high assembly and operating temperatures
Solution Approach 1:
The patent changes the material parameter by replacing aluminum wire with tungsten wire, which has a melting point of 3422°C compared to aluminum's 660°C, enabling the electrical interconnections to withstand the high assembly and operating temperatures required for glass-ceramic sealing
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 provides a robust, cost-effective, and thermally matched semiconductor package that maintains a hermetic seal and operates effectively across a wide temperature range, from -192°C to 400°C, suitable for high-temperature semiconductors, while avoiding the limitations of traditional epoxy encapsulants and thermal expansion issues.
Implementation Method 1
The glass ceramic compound chemically bonds to the die, die pad, connector and a portion of all leads extending from the die pad to provide a hermetic seal
Implementation Method 2
thermally match the coefficients of thermal expansion for the sealing material, bonding materials, die and other components
Implementation Method 3
A semiconductor die is bonded to the die pad with a metal braze, a connector adapted to provide electrical interconnections between the die and the semiconductor die is bonded to the die and die pad with metal brazes
Data Source
AI summary
A high temperature, non-cavity package for non-axial electronics is designed using a glass ceramic compound with that is capable of being assembled and operating continuously at temperatures greater that 300-400° C. Metal brazes, such as silver, silver colloid or copper, are used to connect the semiconductor die, lead frame and connectors. The components are also thermally matched such that the packages can be assembled and operating continuously at high temperatures and withstand extreme temperature variations without the bonds failing or the package cracking due to a thermal mismatch.