Power Module Clip-Heatsink Structure for CTE Stress Buffering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor device packages in power modules face challenges such as mismatches in coefficients of thermal expansion (CTE) between different materials, difficulty in assembly, and insufficient thermal dissipation.
Innovation Solution
The semiconductor device package includes a leadframe and a direct bonded metal (DBM) substrate connected to the leadframe. A stress buffer layer is disposed on a clip electrically connected to two semiconductor dies, and a heatsink is positioned on the stress buffer layer. A mold material encapsulates the components, providing thermal and electrical isolation while minimizing CTE mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple different materials are bonded together within the power module package, then functional requirements are met, but mismatches in coefficients of thermal expansion (CTE) occur between materials
Solution Approach 1:
A stress buffer layer is introduced as an intermediary component between the heatsink and the semiconductor dies. This stress buffer layer acts as a mediator that decouples the thermal expansion differences between the heatsink and the semiconductor components, absorbing stress and preventing damage while allowing both materials to maintain their functional properties.
Solution Approach 2:
The stress buffer layer is constructed as a composite structure comprising multiple layers with different material properties. This composite design allows the buffer layer to have intermediate CTE characteristics between the heatsink and semiconductor dies, or to provide mechanical compliance that accommodates CTE mismatches through its layered structure.
2Ease of manufacture
If conventional assembly methods are used for power modules, then manufacturing is simple, but assembly difficulty increases and thermal dissipation is insufficient
Solution Approach 1:
The stress buffer layer is pre-positioned on the heatsink before the semiconductor dies are mounted. This preliminary action prepares the assembly in advance, creating a stress-absorbing interface that simplifies subsequent assembly steps and prevents damage during the bonding process, thereby reducing overall assembly difficulty.
3Device complexity
If conventional heatsink configurations are used, then structure is simple, but thermal dissipation is insufficient
Solution Approach 1:
The stress buffer layer is applied locally at the critical interface between the heatsink and semiconductor dies, where thermal and mechanical stresses are most concentrated. This localized intervention provides stress relief and improves thermal contact at the most critical location without requiring complex modifications to the entire heatsink structure.
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
This configuration enhances electrical, mechanical, and thermal reliability by minimizing CTE mismatches and providing efficient thermal dissipation, while also simplifying the assembly process and reducing soldering requirements.
Implementation Method 1
such semiconductor device packages may suffer from mismatches in coefficients of thermal expansion (CTE) between two or more different types of materials bonded to one another within the packages
Implementation Method 2
a heatsink is disposed on the clip with the stress buffer layer disposed therebetween
Implementation Method 3
providing efficient thermal dissipation
Implementation Method 4
A mold material encapsulates the first semiconductor die, the second semiconductor die, the clip, and the stress buffer layer
Implementation Method 5
providing thermal and electrical isolation
Data Source
AI summary
Described implementations provide wireless, surface mounting of at least two semiconductor die on die attach pads (DAPs) of the semiconductor package, where the at least two semiconductor die are electrically connected by a clip. A stress buffer layer may be provided on the clip, and a heatsink may be provided on the stress buffer layer. The heatsink may be secured with an external mold material.