Power Module Junction Inspection via Thermal Resistance
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Solution Overview
Problem
Existing methods for detecting defects in the junction portion of power modules, such as X-ray or ultrasonic imaging, suffer from low resolution and subjective operator interpretation, leading to potential false defect detection.
Innovation Solution
A method and device that measure thermal resistance by applying a heating current to a power module, measuring voltage changes, and calculating thermal resistance to objectively determine defects in the junction portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If X-ray or ultrasonic imaging is used to detect defects in junction portions, then non-destructive inspection is achieved, but detection accuracy deteriorates due to low resolution and subjective operator interpretation
Solution Approach 1:
The patent replaces the mechanical/optical imaging system (X-ray or ultrasonic) with an electrical measurement system. Instead of using imaging techniques that produce low-resolution pictures requiring subjective interpretation, the invention uses electrical measurements (voltage, current, power consumption) to objectively detect defects in the junction portion, thereby improving measurement precision and detection accuracy
Solution Approach 2:
The patent introduces power consumption as an intermediary parameter to detect defects. Rather than directly imaging the junction portion, the method measures electrical parameters (voltage, current) and uses power consumption characteristics as a mediator to indirectly detect the presence and severity of defects, achieving higher precision without subjective interpretation
2Measurement precision
If power consumption measurement is used to detect defects, then detection accuracy is improved through quantitative measurement, but additional measurement equipment and procedures are required
Solution Approach 1:
The patent makes existing measurement equipment serve multiple functions. The same measurement system used for routine electrical characterization of the semiconductor device is also used for defect detection by analyzing power consumption characteristics. This eliminates the need for separate specialized defect detection equipment, reducing device complexity while maintaining high measurement precision
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 improves detection accuracy by providing a quantitative measurement of thermal resistance, reducing the likelihood of false defects and enhancing the efficiency of the inspection process.
Implementation Method 1
applying a heating current to the power module to heat the power module
Implementation Method 2
a first cooling block... and a second cooling block... provided to cool the power module to be inspected
Data Source
AI summary
A method for inspecting a junction portion of a power module includes measuring a primary voltage for the power module, applying a heating current to the power module to heat the power module, releasing the application of the heating current and simultaneously measuring a secondary voltage for the power module and cooling the power module, calculating a temperature change amount based on the measured value of the primary voltage and the measured value of the secondary voltage, calculating thermal resistance based on an amount of power applied to the power module and the calculated amount of temperature change, and determining whether the junction portion of the power module is defective, based on the calculated thermal resistance.