Power Semiconductor Module Bonding Layer for Uniform Stress Cooling
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Solution Overview
Problem
Existing power semiconductor modules with double side cooling packages face challenges in ensuring uniform stress distribution during assembly, leading to potential damage and increased scrap rates. Additionally, thermal conductive silicone grease used in heat dissipation can dry and fall off over time, reducing heat dissipation capability.
Innovation Solution
A solid-state thermal conductive layer with metal bonding wires is formed between the heat sink and the power semiconductor package, providing a fastening function that ensures uniform stress distribution and is less likely to fall off. This layer is created through heating and pressing, forming molecular bonding forces between the heat sink, thermal conductive layer, and power semiconductor package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal conductive silicone grease is used between heat sink and power semiconductor package, then heat dissipation capability is improved, but the grease dries and falls off over time reducing reliability
Solution Approach 1:
The patent changes the physical state of the thermal conductive material from liquid (silicone grease) to solid state. The solid-state thermal conductive layer maintains its shape and bonding properties over time, eliminating the drying and falling off issues associated with liquid grease while preserving heat dissipation capability.
Solution Approach 2:
The patent uses a composite structure consisting of a substrate and a thermal conductive layer with metal bonding wires. This composite material combines the heat conduction properties of thermal conductive materials with the mechanical strength and stability of metal bonding wires, creating a reliable long-term solution.
2Temperature
If mechanical structure is used to press heat sinks, then heat dissipation capability is improved, but uniform stress distribution cannot be ensured causing damage during assembly
Solution Approach 1:
The patent replaces the mechanical pressing structure (screws and bolts) with a solid-state thermal conductive layer that inherently provides uniform stress distribution through its material properties and bonding mechanism. This substitution eliminates the stress concentration issues caused by discrete mechanical fasteners.
Solution Approach 2:
The solid-state thermal conductive layer provides homogeneous stress distribution across the entire contact surface between the heat sink and power semiconductor package. The uniform material composition and continuous bonding structure ensure even stress distribution, preventing localized damage during assembly.
3Temperature
If thermal conductive silicone grease is used, then heat dissipation capability is improved, but the grease falls off after a period of time
Solution Approach 1:
The patent changes the physical state from liquid grease to solid material, fundamentally improving the service life. The solid-state thermal conductive layer maintains its integrity and bonding strength throughout the operational lifetime, eliminating the degradation and falling off problems of liquid grease.
Solution Approach 2:
The metal bonding wires are pre-formed and integrated into the solid-state thermal conductive layer during manufacturing, creating strong bonds before the product enters service. This preliminary bonding action ensures long-term stability and prevents material loss during the operational lifetime.
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 ensures uniform stress distribution across the power semiconductor module, reducing the risk of damage during assembly. It also allows for integrated processing and helium inspection of the module before assembly, reducing scrap rates and improving automation and processing speed in motor driver assembly.
Implementation Method 1
a thermal conductive layer (30) located between the heat sink (10) and the power semiconductor package (20)... the thermal conductive layer (30) transfers heat generated by the power semiconductor package (20) to the heat sink (10)
Implementation Method 2
binding force having molecular bonding force is formed between the heat sink and the thermal conductive layer and between the power semiconductor package and the thermal conductive layer
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
This application provides a power semiconductor module, a motor driver, a powertrain, a vehicle, and a method for manufacturing a power semiconductor module. A thermal conductive layer is disposed between a heat sink and a power semiconductor package, where the thermal conductive layer is a thermal conductive material having metal bonding wires on a surface, or is a solid-state thermal conductive layer formed by curable silicone grease, so that both the power semiconductor package and the heat sink are combined with the thermal conductive layer to form the power semiconductor module, thereby reducing a risk of damage caused by stress generated by the power semiconductor module in a process of assembling the entire motor driver. This implements helium inspection of the power semiconductor module in advance, improves a qualification rate of secondary processing of the entire motor driver, and avoids a risk of scrapping the entire motor driver due to air leakage of the heat sink during a helium test of the entire motor driver.