Semiconductor Power Module Resin Structure for Stress Relief
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Solution Overview
Problem
Conventional semiconductor power packages face challenges in achieving mechanical stability and reliable functionality due to conflicting requirements for encapsulation materials, leading to issues like mechanical and thermo-mechanical stress, bowing, and damage from adhesion of different resin materials.
Innovation Solution
The semiconductor power module employs a resin body composed of multiple resin elements with different materials, separated by recesses or grooves to form stress relief structures, using methods like cutting, milling, laser cutting, or etching, and filled/coated with elastic materials to reduce stress and improve mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single resin material is used for encapsulation, then the manufacturing process is simple, but mechanical stability and reliability deteriorate due to conflicting requirements for different regions
Solution Approach 1:
The encapsulation resin is divided into multiple resin elements (first resin element and second resin element) with different materials, each optimized for specific regions. The first resin element contacts the semiconductor chip while the second resin element contacts the heatsink, allowing each material to be tailored for its specific functional requirements rather than using a single compromise material throughout.
Solution Approach 2:
Different resin materials are assigned to different spatial locations within the encapsulation. The first resin element uses a material optimized for chip interface properties while the second resin element uses a material optimized for heatsink interface properties, ensuring local optimization of mechanical and thermal properties for each region's specific requirements.
2Reliability
If different resin materials are used for different regions, then mechanical stability and reliability improve, but mechanical and thermo-mechanical stress increases due to adhesion between different resin materials
Solution Approach 1:
The adhesive interface between the first and second resin elements is completely removed by introducing a recess that extends from the outer surface to the inner surface of the encapsulation. This eliminates the problematic adhesion zone where thermo-mechanical stress would concentrate, allowing the different resin materials to be joined without direct contact and associated stress.
Solution Approach 2:
The recess structure acts as an intermediary zone between the first and second resin elements. By providing a physical separation and elimination of the adhesive interface, the recess mediates the transition between different resin materials without allowing direct adhesion, thereby preventing stress concentration at the material boundary.
3Reliability
If different resin materials are used for encapsulation, then module reliability in high voltage applications improves, but device complexity increases due to multiple resin elements and recess structures
Solution Approach 1:
The encapsulation is segmented into distinct resin elements separated by a recess, creating a modular structure where each element can be independently optimized and manufactured. This segmentation allows for simplified processing of each resin element while maintaining overall system reliability through their coordinated arrangement.
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 design enhances module life and reliability, particularly in high voltage applications, by reducing mechanical and thermo-mechanical stress, preventing damage, and improving thermal cycling performance.
Implementation Method 1
The specifically introduced one or more recesses form stress relief structures between several parts of different resin materials of a resin sealed semiconductor power package
Implementation Method 2
The recess in form of a groove is mechanically formed by means of at least one of cutting, sawing or milling, or thermally formed by means of laser cutting
Data Source
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AI summary
A semiconductor power module (10) for a semiconductor device comprises a leadframe or substrate (4) and a resin body that is coupled to the leadframe or substrate (4). The resin body includes at least a first resin element (1) and a second resin element (2), wherein a resin material of the first resin element (1) is different from a resin material of the second resin element (2). The resin elements (1, 2) are configured such that they are separated in part at least with respect to surface areas facing each other by means of a recess (5, 6).