Emitter Sub-Electrode Voltage Sensing for Bond Wire Degradation
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Solution Overview
Problem
Existing power semiconductor devices fail to accurately distinguish between bonding wires that degrade in an early stage and those that degrade in a terminal stage due to thermal expansion differences, leading to incomplete degradation detection.
Innovation Solution
The semiconductor device divides the emitter electrode into multiple sub-electrodes and uses voltage detectors to monitor the voltage between these sub-electrodes and a terminal, allowing for separate detection of bonding wire degradation in early and terminal stages by measuring voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the emitter electrode is divided into multiple sub-electrodes and voltage detection is implemented, then degradation detection precision is improved, but device complexity increases
Solution Approach 1:
The emitter electrode is divided into multiple sub-electrodes (first sub-electrode, second sub-electrode, etc.) corresponding to different bonding wire groups. This segmentation allows independent voltage detection for each sub-electrode, enabling precise identification of which specific bonding wires have degraded without requiring complex external detection equipment.
Solution Approach 2:
The semiconductor device performs self-diagnosis by using its own internal voltage detection capability to monitor degradation of its bonding wires. The detection circuit measures voltage between sub-electrodes and the emitter terminal, and the device itself determines degradation status based on whether detected voltage exceeds threshold values, eliminating the need for external diagnostic equipment.
2Reliability
If separate detection of early and terminal stage degradation is implemented, then reliability assessment accuracy is improved, but measurement complexity increases
Solution Approach 1:
Different regions of the semiconductor device are assigned different detection thresholds based on their degradation characteristics. The first sub-electrode (central region) uses a first threshold voltage for early-stage degradation detection, while the second sub-electrode (peripheral region) uses a second threshold voltage for terminal-stage degradation detection. This localized threshold assignment enables accurate differentiation between early and terminal degradation stages.
Solution Approach 2:
The detection system uses different voltage threshold parameters to distinguish between different degradation stages. By comparing detected voltage values against predetermined first and second threshold voltages, the system can identify whether degradation is in an early stage (first threshold exceeded) or terminal stage (second threshold exceeded), providing staged reliability assessment without complex analysis.
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 enables precise detection of bonding wire degradation, allowing for accurate assessment of the device's overall condition and remaining life, as well as monitoring temperature and cooling performance.
Implementation Method 1
a first voltage detector to detect a voltage between the first sub-electrode and the first terminal
Implementation Method 2
a second voltage detector to detect a voltage between the second sub-electrode and the first terminal
Implementation Method 3
the bonding wires to degrade due to a difference in coefficient of linear expansion between the bonding wires and the emitter electrode
Data Source
AI summary
In this semiconductor device, an emitter electrode of a power semiconductor element includes a first sub-electrode provided in a region including a central portion of a front surface of a semiconductor substrate and a second sub-electrode provided in a region not including the central portion of the front surface of the semiconductor substrate. A first bonding wire connects the first sub-electrode and an emitter terminal. A second bonding wire connects the second sub-electrode and the emitter terminal. First and second voltage detectors detect voltages between the emitter terminal and the first and second sub-electrodes, respectively. It is possible to separately detect degradation of both the first bonding wire that degrades in an early period and the second bonding wire that degrades in a terminal period.