Power Semiconductor Module Aging Detection via Potting Capacitance

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Solution Overview

Problem

Existing methods for assessing the operating state of power semiconductor modules are complex, costly, and not feasible in real-world environments, especially due to the challenges of thermal stress and foreign substance diffusion affecting the encapsulant, which complicates the detection of aging and potential failures.

Innovation Solution

A method and system that measure the electrical properties of a capacitive arrangement within the module, utilizing the potting compound as a dielectric, to detect changes indicative of aging and potential failures, allowing for non-destructive, reliable assessment of the module's condition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If imaging techniques such as X-rays, ultrasound microscopy, and thermography are used to detect aging phenomena, then measurement precision is improved, but device complexity and cost increase significantly

Engineering Contradiction:

Improvedetection capabilityVSAvoidcomplexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a capacitive arrangement as an intermediary sensing element that indirectly detects aging of the power semiconductor module through changes in the potting compound's electrical properties. This mediator converts complex aging phenomena (thermal stress, foreign substance diffusion, bond wire degradation) into simple capacitance measurements, avoiding the need for complex imaging equipment while maintaining detection capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces complex mechanical/imaging detection systems (X-ray, ultrasound, thermography) with an electrical measurement system based on capacitance sensing. This substitution simplifies the detection mechanism by using electrical fields instead of mechanical or optical fields, reducing device complexity while preserving measurement precision for aging detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If accelerated aging tests and microsection analysis are performed to verify module aging, then reliability assessment is improved, but loss of time and productivity decrease

Engineering Contradiction:

Improveservice life predictionVSAvoidtesting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary monitoring by continuously or periodically measuring capacitance changes during module operation or storage. This allows early detection of aging trends before failure occurs, eliminating the need for time-consuming post-test microsection analysis while maintaining reliable service life prediction through trend analysis of capacitance data

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent enables the power semiconductor module to self-diagnose its aging state through the capacitive arrangement that is already integrated into its structure. The module's own potting compound and capacitive elements serve as the sensing mechanism, eliminating the need for external complex testing equipment and reducing testing time while maintaining reliability assessment accuracy

Inventive Principle:

Principle #25Self-service

3Reliability

If the module is encapsulated with potting compound to protect against corrosion, then reliability is improved, but difficulty of detecting and measuring operating state increases

Engineering Contradiction:

Improveprotection against corrosionVSAvoidintegrity assessment

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent makes the potting compound multi-functional by using it both as a protective encapsulant and as a dielectric medium for capacitance sensing. This dual function allows the same material to provide corrosion protection while simultaneously enabling non-invasive detection of aging and foreign substance diffusion, eliminating the conflict between protection and detectability

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Provides a simple, cost-effective, and reliable means to assess the aging and operational state of power semiconductor modules, enabling predictive maintenance and preventing unplanned failures by monitoring the electrical properties of the potting compound.

Implementation Method 1

Determining the electrical properties of at least one capacitive arrangement located within the semiconductor module, comprising two spaced-apart, conductive, mutually electrically insulated components and an electrical insulator in the form of a part of the potting compound located between these components

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

an electrical insulator in the form of a part of the potting compound located between these components

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentEP4610673A1Method and system for checking the operating state of a power semiconductor module

Publication Date: 2025.09.03 SIEMENS AG

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AI summary

The invention relates to a method and a system for checking the operating state of a power semiconductor module.