The Quality Evaluating Method Of Semiconductor Power Devices Based On Infrared Thermal Analysis

Anything can radiate infrared if its temperature is above absolute zero. Infrared detecting temperature is a method which is based object's infrared radiation and emission determined by its material characteristic. Infrared detecting temperature play a important role in failure position and reliability evaluating at circuits, devices and power modules.Failure of power devices induced mainly by over heat. Comparing thermal profile of one device with standard thermal profile(STP), we can evaluate its reliability quickly and effectively, and find the approach failure of devices. Suddenly failure of our military equipment can be avoided.After reliability test of temperature cycle and thermal impact, the electrics parameter of two power transistor 3DD5H and 3DD114B with low frequent and high bias voltage is still eligible, but their solder and pedestal has a lot of hollow. After reliability test of thermal impact applying power, second breakdown take place in the device. As forward base state, the current is collecting at the edge of emitter and the breakdown point was found in there. Because of high doping underlay, the V_CES of device don't increase obviously.Using digital image processing technology, infrared thermal profile can be improved. Comparing to the bicubic interpolations, the method of spline interpolation is better. Image is processed by the former can be more continuously, sharply and its brim transiting more smoothly. When temperature is below 100 degree, the error of interpolation temperature is less than 0.5 degree, the veracity is improved 35.9 percent. When temperature is about 120 degree, the error of interpolation temperature is less than 13 degree, the veracity is improved 41.7 percent.