Semiconductor Module Cooling Chamber with Zigzag Fins
Solution Overview
Problem
Semiconductor modules used in power conversion apparatuses for hybrid or electric automobiles face thermal stress issues due to differing linear expansion coefficients between the cooling chamber and the layered substrate, leading to cracking and breaking during heat cycle testing.
Innovation Solution
A semiconductor module design featuring a layered substrate with a circuit board, insulating board, and metal board, where a cooling chamber with zigzag fins is bonded to the metal board using solder, forming a coolant flow path that reduces thermal stress by minimizing flexing and enhancing heat release efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling chamber is bonded to a layered substrate, then heat dissipation is improved, but thermal stress causes cracking and breaking due to differing linear expansion coefficients
Solution Approach 1:
The cooling chamber is divided into multiple segments along the coolant flow direction, with each segment containing zigzag fins. This segmentation allows each segment to independently accommodate thermal expansion, reducing stress concentration and preventing cracking in the solder joints while maintaining effective heat dissipation across the entire structure.
Solution Approach 2:
The linear expansion coefficient of the cooling chamber is made substantially equal to that of the layered substrate by selecting appropriate materials and design parameters. This parameter matching minimizes thermal stress during temperature cycles, preventing solder joint failure while preserving the heat dissipation function.
2Temperature
If zigzag fins are added to the cooling chamber, then heat release efficiency is enhanced, but device complexity increases
Solution Approach 1:
Zigzag fins with curved surfaces are employed instead of straight fins. The curved geometry increases the heat exchange surface area and improves coolant flow characteristics, enhancing heat release efficiency.同时, the zigzag pattern can be integrated into the cooling chamber manufacturing process, managing the complexity through standardized design.
3Manufacturing precision
If the cooling chamber is made rigid for structural stability, then manufacturing precision is improved, but thermal stress from expansion mismatch increases
Solution Approach 1:
Dividing the cooling chamber into multiple rigid segments allows each segment to maintain manufacturing precision and structural stability individually, while the segmented structure as a whole can accommodate thermal expansion through the compliance of inter-segment joints and the zigzag fin geometry, reducing overall thermal stress.
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 design effectively reduces cracking and improves reliability by managing thermal stress and enhancing heat dissipation, thereby extending the low cycle fatigue lifetime of the solder layer.
Implementation Method 1
a flow path through which a coolant passes is formed by the first board portion, the second board portion, and the plurality of zigzag fins
Implementation Method 2
the cooling chamber cooling a layered substrate on which the power semiconductor element is mounted has a linear expansion coefficient that differs from that of the layered substrate by several times
Implementation Method 3
When heat cycle testing is performed on such a semiconductor module, thermal stress occurs in the solder layer bonding this layered substrate and the cooling chamber, causing cracking and/or breaking
Data Source
AI summary
To bond a layered substrate and a cooling chamber having different linear expansion coefficients while preventing cracking and breaking, provided is a semiconductor module including a layered substrate formed by layering a circuit board, an insulating board, and a metal board; a semiconductor chip mounted on the circuit board; and a cooling chamber bonded to the metal board by solder. The cooling chamber includes a first board portion bonded to the metal board; a second board portion facing the first board portion; and a plurality of zigzag fins arranged between the first board portion and the second board portion. The plurality of zigzag fins are joined to the first board portion and the second board portion, and a flow path through which a coolant passes is formed by the first board portion, the second board portion, and the plurality of zigzag fins.