Power Semiconductor Module Silicone Gel Potting Leakage Current
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Solution Overview
Problem
Existing power semiconductor modules face challenges with high leakage current due to charge accumulation and reduced withstand voltage, particularly with the use of guard rings and potting materials, which require complex operations, high costs, and susceptibility to cracking and ion concentration issues.
Innovation Solution
A power semiconductor module incorporating a silicone gel potting material with a conductivity-imparting agent containing silicon atoms and anionic groups, which reduces insulation resistance at boundaries and maintains long-term electric field relaxation without a two-layer structure, thereby minimizing leakage current and preventing cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guard ring is provided around semiconductor elements to relax electric field and suppress charge accumulation, then withstand voltage is improved, but leakage current inside the semiconductor element increases
Solution Approach 1:
A gel material is introduced as an intermediary substance between the semiconductor element and the potting material. This gel material has intermediate electrical properties that prevent charge accumulation on the semiconductor element surface while avoiding excessive leakage current, thus resolving the contradiction between withstand voltage and leakage current
Solution Approach 2:
The patent uses a composite structure combining gel material with potting material. The gel material layer is formulated with specific composition (including silicone resin and fillers) to create a composite system that simultaneously achieves electric field relaxation and leakage current suppression
2Reliability
If epoxy resin is used as potting material with semiconductive particles, then electric field can be relaxed, but ceramic substrate suffers from cracking due to curing shrinkage
Solution Approach 1:
The patent changes the chemical composition parameters of the potting material from epoxy resin to a silicone-based resin system. This fundamental material parameter change eliminates the curing shrinkage issue while maintaining the electric field relaxation function through carefully selected filler particles
Solution Approach 2:
The patent develops a composite material system using silicone resin combined with specific inorganic fillers (such as alumina or silica particles). This composite approach provides both the mechanical flexibility needed to prevent substrate cracking and the electrical properties needed for electric field relaxation
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 effectively reduces leakage current and maintains high withstand voltage by uniformly distributing the conductivity-imparting agent, preventing charge accumulation and substrate cracking, while ensuring reliable long-term electric field relaxation.
Implementation Method 1
a conductivity-imparting agent that is added to the silicone gel and contains a silicon atom and anionic group
Implementation Method 2
a guard ring is provided around the semiconductor elements to relax an electric field generated in this portion as well as suppress charge accumulation on the surface of the semiconductor elements
Data Source
AI summary
Provided is a power semiconductor module including: a metal base plate; an insulating substrate arranged on the metal base plate and provided with an electrode; a semiconductor element arranged on the insulating substrate; a case arranged on the metal base plate so as to surround the insulating substrate and the semiconductor element; and a potting material filled into a space defined by the metal base plate and the case so as to encapsulate the insulating substrate and the semiconductor element. The potting material includes: a silicone gel; and a conductivity-imparting agent that is added to the gel and contains a silicon atom and an ionic group.