Semiconductor Device Thermal Buffer for Noise and Stress
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Solution Overview
Problem
Semiconductor devices with arm series circuits face issues with stray capacitance, leading to conduction noise and radiation noise due to common-mode currents, which existing solutions have not adequately addressed.
Innovation Solution
Incorporating conductive thermal buffer members with specific linear expansion coefficients between switching devices and terminals in semiconductor devices, increasing the distance between output terminals and ground, thereby reducing stray capacitance and common-mode currents, and managing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the output terminal is directly connected to external components without an insulating substrate to reduce stray capacitance, then conduction noise and radiation noise are suppressed, but thermal stress management becomes difficult due to direct thermal contact between switching devices and terminals
Solution Approach 1:
A thermal buffer member is introduced as an intermediary component between the switching device and the terminal. This buffer member has a linear expansion coefficient that is higher than the switching device but lower than the terminal, creating a gradient that gradually transitions thermal expansion characteristics. This intermediary structure maintains the direct electrical connection needed for low stray capacitance while providing thermal management through controlled expansion differences, thus resolving the contradiction between noise suppression and thermal stress management.
Solution Approach 2:
The invention utilizes differential thermal expansion properties by selecting materials with specific linear expansion coefficients for the thermal buffer member. The buffer member's expansion coefficient is deliberately chosen to be between that of the switching device and the terminal, allowing it to absorb thermal stress during temperature cycles. This approach directly addresses the thermal stress issue while preserving the direct connection structure needed for reducing conduction and radiation noise.
2Temperature
If thermal buffer members with intermediate linear expansion coefficients are introduced between switching devices and terminals, then thermal stress is managed, but device complexity increases
Solution Approach 1:
The thermal buffer member is designed to serve multiple functions simultaneously: it provides thermal stress management through differential expansion, maintains electrical connectivity between components, and contributes to mechanical bonding of the module structure. By consolidating these functions into a single component rather than adding separate elements, the invention manages thermal stress without proportionally increasing structural complexity.
Solution Approach 2:
The thermal buffer member is constructed from composite materials or material combinations that achieve the desired intermediate linear expansion coefficient. This allows the single component to exhibit graded thermal properties, effectively bridging the expansion difference between the switching device and terminal while maintaining structural integrity and electrical conductivity, thereby managing thermal stress without significantly complicating the device architecture.
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 effectively suppresses conduction and radiation noise by reducing stray capacitance and alleviating thermal stress, enhancing the reliability of semiconductor devices.
Implementation Method 1
The first thermal buffer member has a linear expansion coefficient greater than a linear expansion coefficient of the first switching device and smaller than a linear expansion coefficient of the positive-electrode terminal or the output terminal
Data Source
AI summary
A semiconductor device includes at least one arm series circuit, a conductive first thermal buffer member, and a conductive second thermal buffer member. The arm series circuit includes an upper arm, a lower arm, a positive-electrode terminal, a negative-electrode terminal, and an output terminal. The first thermal buffer member has a linear expansion coefficient greater than a linear expansion coefficient of the first switching device and smaller than a linear expansion coefficient of one of the positive-electrode terminal and the output terminal. The second thermal buffer member has a linear expansion coefficient greater than a linear expansion coefficient of the second switching device and smaller than a linear expansion coefficient of one of the negative-electrode terminal and the output terminal.