Semiconductor External Electrode Thermal Expansion Fixation
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Solution Overview
Problem
High-voltage semiconductor power modules face issues with secure fixation of external electrodes due to heat-induced expansion of the resin case, leading to instability in the collector external electrode.
Innovation Solution
The semiconductor device incorporates a main current external electrode with a press-fitted fixing portion and a claw fixing portion, featuring projections that pass through holes in the resin case and include a bendable claw portion for multi-point secure fixation, enhancing stability and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the collector external electrode is fixed by press fitting into the resin case, then the manufacturing cost is reduced, but the fixation becomes loose due to heat-induced expansion of the resin case
Solution Approach 1:
The external electrode is divided into multiple fixation portions (press-fitted fixation portions and claw fixation portions) distributed along its length. This segmentation allows different fixation mechanisms to work together, with the claw portions providing additional anchoring points that prevent loosening due to thermal expansion while maintaining the simple press-fitting manufacturing process
Solution Approach 2:
The fixation mechanism transitions from a single-dimensional press-fitting approach to a multi-dimensional solution by adding claw portions that extend radially outward from the electrode. These claws engage with the resin case in a different spatial dimension, creating a three-dimensional fixation system that resists thermal expansion forces more effectively
2Reliability
If the resin case expands due to heat generation during assembly, then the fixation of the collector external electrode is loosened, but adding complex fixation structures increases manufacturing cost
Solution Approach 1:
The invention merges the press-fitting fixation method with a claw-type fixation structure into a single integrated external electrode design. The external electrode itself forms both the press-fitted portions and the claw portions, combining two fixation mechanisms without adding separate components, thus maintaining manufacturing simplicity while achieving secure fixation
Solution Approach 2:
The external electrode structure is designed to be self-fixing through its own geometry. The claw portions are formed as integral parts of the electrode that automatically engage with the resin case during press-fitting, eliminating the need for additional fixation components or complex assembly processes while providing robust thermal expansion compensation
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 solution provides a secure and stable fixation of the collector external electrode, maintaining isolation and insulation distances even at high voltages, ensuring reliable operation of high-voltage power modules.
Implementation Method 1
The claw portion (4) is bendable and extends along a surface of the resin case (2) in which the through hole is defined
Implementation Method 2
the case may expand due to heat generation during the assembly so the fixation of the collector external may be loosened
Data Source
AI summary
A semiconductor device includes a main current external electrode for connecting a high-voltage main current electrode of a power semiconductor element to the outside, and a resin case into which the main current external electrode is press fitted. The main current external electrode has a press-fitted fixing portion and a claw fixing portion for fixation to the resin case. The claw fixing portion includes a projection passing through a through hole defined in the resin case, and having a bendable claw portion at its tip end.