Dual Potting Material Semiconductor Power Module
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Solution Overview
Problem
High-power semiconductor packages face insulation failure due to rapid degradation of potting materials at elevated temperatures, leading to weight loss, reduced elongation, and increased hardness, which compromises electrical insulation and increases the risk of crack formation.
Innovation Solution
A semiconductor power module design featuring a dual potting material system, where a high-temperature stable, thermally conductive first potting material is applied selectively to hotspots and a more conventional, creepable second potting material is used elsewhere, ensuring effective heat dissipation and insulation across varying temperature zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single potting material is used to cover the semiconductor die and electrical connectors, then the manufacturing process is simple, but the potting material degrades rapidly at high temperatures (200°C and above) leading to weight loss, reduced elongation, increased hardness, and electrical insulation failure
Solution Approach 1:
The patent divides the potting material into two distinct segments: a first potting material applied to hotspots (semiconductor die and electrical connectors) that can withstand high temperatures, and a second potting material applied to cooler areas that provides good creepability and filling. This segmentation allows each material to be optimized for its specific thermal environment, resolving the contradiction between manufacturing simplicity and insulation reliability at high temperatures.
Solution Approach 2:
The patent applies different material properties to different locations based on thermal requirements. The first potting material with high temperature stability is applied locally to hotspot areas (die and connectors), while the second material with better creepability is applied to cooler surrounding areas. This local differentiation resolves the contradiction by ensuring insulation integrity where it's most needed while maintaining overall package performance.
2Reliability
If a high-temperature stable potting material is used, then insulation integrity is maintained at elevated temperatures, but the material may have reduced creepability and increased hardness
Solution Approach 1:
The patent segments the potting material application into two zones: hotspot areas requiring high temperature stability and cooler areas requiring good creepability. By applying the first potting material only to the semiconductor die and electrical connectors (hotspots) and the second material to the remaining housing space, the patent achieves both insulation integrity at high temperatures and adequate creepability in cooler regions without compromising either property.
Solution Approach 2:
The patent implements local quality by matching material properties to local thermal conditions. The first potting material is selected for high temperature stability to maintain insulation where needed most, while the second material provides superior creepability in areas where thermal stress is lower. This localized optimization resolves the contradiction between maintaining insulation integrity and preserving creepability.
3Ease of operation
If conventional potting materials (silicone gel, epoxy resin, acrylate) are used, then good creepability and filling properties are achieved, but the materials degrade at temperatures above 125-175°C with weight loss, oxidation, and crack formation
Solution Approach 1:
The patent segments the protective coating into two functional layers: a first potting material layer applied to critical high-temperature components (die and connectors) that provides thermal stability and prevents degradation, and a second conventional potting material layer applied to cooler areas that provides excellent creepability and void-free filling. This segmentation allows the use of conventional materials in appropriate zones without compromising operational lifespan at high temperatures.
Solution Approach 2:
The patent applies local quality by selecting potting materials based on local thermal exposure. Conventional materials with good creepability are applied locally to areas with lower thermal stress, while high-temperature stable materials are applied to components experiencing the highest temperatures. This resolves the contradiction by ensuring both long operational lifespan in hot zones and excellent creepability in cooler zones.
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 dual potting material system significantly reduces weight loss and elongation reduction, maintaining insulation integrity and extending the module's operational lifespan up to 300°C with minimal weight loss and thermal aging effects.
Implementation Method 1
a first potting material covering at least selective portions of the semiconductor transistor die and the electrical connector
Implementation Method 2
The dual potting material system significantly reduces weight loss and elongation reduction, maintaining insulation integrity and extending the module's operational lifespan up to 300°C with minimal weight loss and thermal aging effects
Data Source
AI summary
A semiconductor power module comprises an insulating interposer comprising an insulative layer disposed between a lower metal layer, a first upper metal layer and a second upper metal layer, a semiconductor transistor die disposed on the first upper metal layer, an electrical connector connecting the semiconductor transistor die with the second upper metal layer, a housing enclosing the insulating interposer and the semiconductor transistor die, a first potting material covering at least selective portions of the semiconductor transistor die and the electrical connector; and a second potting material applied onto the first potting material, wherein the first and second potting materials are different from each other.