Power Semiconductor Wire Bond Degradation Detection Circuit
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Solution Overview
Problem
Semiconductor devices using power semiconductor elements, such as IGBTs, experience degradation over time due to thermal expansion and contraction, leading to cracks and potential failure at the joint portions between the semiconductor element and wires, which existing detection methods fail to accurately predict.
Innovation Solution
A semiconductor device with a degradation detection circuit that monitors the voltage change on a wire bonded to the current output electrode of the power semiconductor element while a constant current flows, under specific conditions of the element being in a turn-off state and within a predetermined temperature range, to detect resistance increases indicative of degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing detection methods are used to monitor degradation, then the device can operate for extended periods, but the detection accuracy is insufficient to predict failures before they occur
Solution Approach 1:
The patent applies preliminary action by detecting degradation trends before failure occurs. The control circuit continuously monitors voltage values during constant current periods and calculates resistance values in advance, identifying degradation patterns that predict future failures. This allows the system to take preventive action before actual failure happens, resolving the contradiction between extended operation and reliable failure prediction.
Solution Approach 2:
The patent implements feedback by continuously monitoring voltage values, calculating resistance values, and comparing them against threshold values. The control circuit uses this feedback loop to detect degradation trends and predict failures with high accuracy. The system adjusts its monitoring and prediction based on the accumulated data, improving both measurement precision and failure prediction reliability simultaneously.
2Reliability
If continuous monitoring is performed to detect degradation, then failure can be prevented, but power consumption and operational complexity increase
Solution Approach 1:
The patent applies periodic action by monitoring voltage values only during constant current periods when the semiconductor element is in a stable state. The control circuit periodically calculates resistance values at these specific intervals rather than continuously, reducing power consumption while maintaining reliable degradation detection. This periodic monitoring approach prevents failure while minimizing energy usage.
Solution Approach 2:
The patent uses partial action by monitoring only the voltage across the wire during constant current periods, rather than continuously monitoring all device parameters. This selective monitoring of critical parameters during specific operational phases achieves reliable failure prevention without the excessive power consumption of comprehensive continuous monitoring.
3Measurement precision
If monitoring is performed during switching operations, then real-time degradation detection is achieved, but false detections occur due to transient voltage fluctuations
Solution Approach 1:
The patent applies local quality by monitoring voltage values at specific locations and times - specifically during constant current periods when the semiconductor element is in a stable state. The control circuit focuses measurement resources on these critical moments when degradation signals are most reliable, avoiding transient periods that cause false detections. This selective local monitoring achieves real-time detection accuracy without false alarms.
Solution Approach 2:
The patent uses preliminary action by identifying and monitoring during constant current periods before transient fluctuations occur. The control circuit detects degradation during these stable preliminary phases, avoiding the noisy switching transitions that cause false detections. This timing-based selection eliminates false positives while maintaining real-time detection capability.
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
Accurately detects degradation in the joint portion before it leads to failure, allowing for timely replacement and preventing device breakdown by monitoring voltage changes with high precision.
Implementation Method 1
a wire (w1) bonded to the current output electrode (1a1)
Implementation Method 2
monitor a temporal change of a voltage value of the wire while a constant current flows through the wire
Implementation Method 3
the power semiconductor element is in a turn-off state
Data Source
AI summary
A semiconductor device, including: a power semiconductor element having a current output electrode; a wire bonded to the current output electrode; and a degradation detection circuit configured to monitor a temporal change of a voltage value of the wire while a constant current flows through the wire, responsive to satisfaction of a plurality of conditions including that the power semiconductor element is in a turn-off state, and that a temperature of the power semiconductor element is within a predetermined temperature range.