Power Semiconductor Weld Inspection
views：9
author：admin
source：Hiwave
time：2025-10-17
catogory：Industry News
In power electronic systems, the reliability of high-power semiconductor devices is critical. The chip is bonded to a copper substrate via a solder layer, serving both……
In power electronic systems, the reliability of high-power semiconductor devices is critical. The chip is bonded to a copper substrate via a solder layer, serving both electrical conduction and heat dissipation functions. Thus, the quality of this bond directly impacts device performance and longevity.
Traditional destructive testing methods are costly and unsuitable for mass production. Scanning Acoustic Microscopy (SAM) has become an essential tool for solder joint inspection, offering a non-contact, non-destructive imaging solution.
Principle
SAM detects internal structures by analyzing ultrasonic reflections at material interfaces. Variations in density or acoustic impedance—such as at voids or delaminations—produce strong echoes, which the system uses to generate internal images.
This evaluation employs a 15 MHz focused transducer with a 0.75-inch (19.05 mm) diameter. This configuration balances resolution and penetration depth, making it ideal for medium-thickness packages like IGBTs and power MOSFETs.
Defect Detection
C-Scan imaging provides a clear view of the solder interface:
Dark areas (blue/green): Indicate good bonding with minimal reflection.
Bright areas (red/white): Represent strong reflections, typically caused by voids, delamination, or cracks.
Such defects impede heat transfer, leading to localized overheating, thermal stress, and eventual device failure. SAM accurately quantifies defect size, location, and distribution, supporting process optimization.
With its high sensitivity, resolution, and non-destructive nature, SAM has become a standard method for evaluating solder joint quality in high-power devices, playing a vital role in ensuring product reliability and advancing power electronics technology.
