IGBT Lifetime Prediction via Bonding Wire and Solder Layer Coupling
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Solution Overview
Problem
Current IGBT lifetime prediction models lack accuracy due to the impact of random probability distribution and focus on specific failure modes, making it difficult to account for the coupling effects between bonding wires and solder layers, which affects the reliability of IGBT modules in high-voltage and high-power applications.
Innovation Solution
A method and system for predicting IGBT lifetime based on compound failure mode coupling, which involves calculating simultaneous failure probability models for bonding wires and solder layers, establishing a coupling function relation, and incorporating this coupling effect into IGBT lifetime prediction models to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If empirical lifetime models with multiple undetermined coefficients (e.g., Bayerer model) are used to improve prediction accuracy, then prediction accuracy is improved, but model complexity and difficulty of fitting increase significantly
Solution Approach 1:
The patent segments the IGBT failure modes into distinct components (bonding wire fatigue, solder layer fatigue, bond chip cracks) and develops separate lifetime prediction models for each component. This segmentation allows each sub-model to focus on specific failure mechanisms with fewer parameters, reducing overall model complexity while maintaining comprehensive prediction accuracy.
Solution Approach 2:
The patent transforms the complex multi-parameter empirical model into a simplified framework by changing the approach from fitting multiple undetermined coefficients to using physics-based parameters (cycle counts, temperature ranges, material properties) that can be directly measured or calculated, thereby reducing fitting difficulty while preserving prediction accuracy.
2Device complexity
If physical lifetime models based on failure physics are used to simplify the model structure, then model simplicity is improved, but prediction accuracy deteriorates due to not considering random probability distribution and coupling effects
Solution Approach 1:
The patent merges the simplicity of physical models with the accuracy of statistical models by combining physics-based failure mechanisms (thermo-mechanical fatigue, creep) with probability distribution functions (Weibull distribution) and coupling effects. This integration creates a hybrid model that maintains structural simplicity while incorporating random variability and interaction effects for improved prediction accuracy.
Solution Approach 2:
The patent creates a composite modeling approach that combines physical failure mechanisms with statistical probability distributions and coupling relationships. This composite model structure integrates multiple modeling paradigms (physics-based, statistical, system-level coupling) to achieve both simplicity and accuracy simultaneously.
3Device complexity
If lifetime prediction models focus on specific failure modes independently to reduce model complexity, then model complexity is reduced, but prediction accuracy deteriorates due to ignoring coupling effects between bonding wires and solder layers
Solution Approach 1:
The patent introduces a coupling mechanism as an intermediary that connects the independent failure mode models. This coupling layer captures the interactions between bonding wire fatigue, solder layer fatigue, and bond chip cracks, allowing each component model to remain relatively simple while the coupling mechanism accounts for their interdependencies, thereby maintaining both simplicity and accuracy.
Data Source
AI summary
A method and system for predicting an insulated gate bipolar transistor (IGBT) lifetime based on compound failure mode coupling are provided. First, a simultaneous failure probability model of a bonding wire and a solder layer is calculated. Next, expectancy of the simultaneous failure probability model is calculated and recorded as a lifetime under a coupling effect. A coupling function relation is established. A lifetime of the solder layer and a lifetime of the bonding wire are predicted. An IGBT lifetime prediction model not taking the coupling effect into account is established. An IGBT lifetime prediction model taking the coupling effect into account is established. In the disclosure, the lifetime of the IGBT module under the coupling effect of the solder layer and the bonding wire may be accurately predicted.