IGBT Module Bonding Wire Resistance Evaluation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Accurately evaluating the reliability of Insulate-Gate Bipolar Transistor (IGBT) modules is challenging due to the difficulty in directly measuring bonding wire parameters, which are crucial for assessing packaging failures, as they account for more than 50% of IGBT failures.
Innovation Solution
A method and device that measure the resistance of bonding wires indirectly by determining the voltage drop at the junction of the IGBT chip and bonding wire, using the relationship between chip conduction voltage drop, operating current, and chip junction temperature to assess IGBT module reliability, with a failure determination based on increased resistance levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bonding wire parameters are directly measured, then measurement precision is improved, but device complexity and difficulty of detecting and measuring increase due to the small size and internal location of bonding wires
Solution Approach 1:
The patent introduces an intermediary measurement approach by measuring the voltage drop across the bonding wire indirectly through terminal voltage measurements, rather than directly probing the bonding wire itself. This mediator measurement method enables accurate bonding wire parameter assessment without the complexity of direct internal measurement
Solution Approach 2:
The patent replaces direct physical measurement of bonding wire parameters with an electrical measurement system that measures voltage drop and calculates resistance indirectly. This substitution transforms a mechanically difficult measurement task into an electrical measurement task that can be performed through terminal connections
2Reliability
If IGBT module reliability evaluation is based on bonding wire degradation, then reliability evaluation accuracy is improved, but device complexity increases due to the need for separate bonding wire failure mode analysis
Solution Approach 1:
The patent segments the IGBT module failure analysis into distinct components: chip conduction voltage drop, external circuit voltage drop, and bonding wire voltage drop. By separating the bonding wire failure mode from other failure modes, the evaluation can focus specifically on bonding wire degradation while maintaining overall system reliability assessment
Solution Approach 2:
The patent extracts the bonding wire resistance component from the total module resistance by subtracting the chip conduction voltage drop and external circuit voltage drop from the total voltage drop. This extraction isolates the bonding wire degradation signal for separate analysis and reliability evaluation
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 approach enhances the accuracy of IGBT module reliability evaluation by separating and measuring bonding wire failures effectively, providing versatility across different temperature environments and improving the detection of solder layer aging and bonding wire issues.
Implementation Method 1
the relationship between IGBT chip conduction voltage drop Uces and the operating current Ie along with chip junction temperature Tc is obtained
Implementation Method 2
chip junction temperature Tc
Data Source
AI summary
The disclosure discloses an IGBT module reliability evaluation method and device based on bonding wire degradation, which belong to the field of IGBT reliability evaluation. The realization of the method includes: obtaining a relationship between a IGBT chip conduction voltage drop Uces and an operating current Ic along with a chip junction temperature Tc; for an IGBT module under test, obtaining the conduction voltage drop Uces-c of the IGBT chip through the operating current Ic and the chip junction temperature Tc; obtaining an external conduction voltage drop Uces-m of the IGBT module by using a voltmeter; performing subtraction to obtain a voltage drop at a junction of a IGBT chip and a bonding wire, and combining the operating current to obtain a resistance at the junction; determining that the IGBT module has failed when the resistance at the junction increases to 5% of an equivalent impedance of the IGBT module.