Power Semiconductor Module Bonding Layer for Uniform Assembly Stress
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Solution Overview
Problem
The existing power semiconductor modules with double side cooling packages face challenges in ensuring uniform stress distribution during assembly, leading to potential damage and reduced heat dissipation due to the use of mechanical structures and thermal conductive interface materials that can dry out or fall off, resulting in increased scrap rates and assembly difficulties.
Innovation Solution
A solid-state thermal conductive layer with metal bonding wires or curable silicone grease is formed between the heat sink and the power semiconductor package, providing a uniform stress distribution and a strong bonding force that prevents the thermal conductive layer from falling off, allowing for integrated processing and helium inspection before motor driver assembly, thus reducing scrap rates and improving assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If mechanical structures (screws and bolts) are used to press and connect heat sinks, then the heat dissipation capability is improved through double side cooling, but uniform stress distribution cannot be ensured leading to potential damage during assembly
Solution Approach 1:
The patent replaces the mechanical pressing structure (screws and bolts) with a solid-state thermal conductive layer that provides both thermal conduction and mechanical bonding functions. This substitution eliminates the stress concentration issues caused by mechanical fasteners while maintaining effective heat dissipation through the thermal conductive layer that bonds the power semiconductor package to the heat sinks.
Solution Approach 2:
The patent employs a composite thermal conductive layer comprising a base material (such as silicone grease, phase change material, or adhesive) combined with metal bonding wires or particles. This composite structure provides both thermal conduction pathways and mechanical bonding strength, distributing stress uniformly across the bonding interface while maintaining efficient heat transfer from the power semiconductor package to the heat sinks.
2Temperature
If thermal conductive silicone grease is used as interface material, then heat transfer is improved, but the material dries and falls off after use reducing heat dissipation capability
Solution Approach 1:
The patent creates a composite thermal conductive layer by combining thermal conductive silicone grease or phase change material with metal bonding wires or particles. The metal components provide long-term structural stability and prevent the organic thermal conductive material from drying out or detaching, while maintaining thermal conduction pathways. This composite structure ensures both effective heat transfer and durable service life.
Solution Approach 2:
The patent applies different materials with complementary properties in specific locations within the thermal conductive layer. The base material (silicone grease or phase change material) provides initial thermal conduction and filling capability, while the embedded metal bonding wires or particles provide long-term structural integrity and prevent material degradation. This local differentiation of material functions resolves the issue of material drying and detachment over time.
3Productivity
If power semiconductor module assembly is performed before motor driver assembly, then stress damage risk increases, but integrated processing and helium inspection can be performed earlier to reduce scrap rates
Solution Approach 1:
The patent enables preliminary assembly of the power semiconductor module with heat sinks using the solid-state thermal conductive layer before motor driver assembly. The innovative thermal conductive layer provides sufficient bonding strength to maintain module integrity during early assembly stages, allowing helium inspection and integrated processing to be performed earlier in the manufacturing process, thereby improving productivity without compromising 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
The solution ensures uniform stress distribution, reduces the risk of damage during assembly, improves heat dissipation capabilities, and enhances the automation and yield of the motor driver assembly process by preventing water leakage issues during testing.
Implementation Method 1
a thermal conductive layer. The thermal conductive layer is located between the heat sink and the power semiconductor package, and the thermal conductive layer is a thermal conductive material having metal bonding wires on a surface or a solid-state thermal conductive layer formed by curable silicone grease
Implementation Method 2
both the power semiconductor package and the heat sink are combined with the thermal conductive layer to form the power semiconductor module
Implementation Method 3
a solid-state thermal conductive layer formed by curable silicone grease
Data Source
AI summary
A power semiconductor module, a motor driver 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.