Research On Methord Of Defects Detection For Electronic Package Based On Infrared Thermography

Due to the dissimilar thermal expansion coefficient and the uncontrollableprocess factors, the various defects will emerge inevitably in the internal structureduring the electronic device packaging and servicing. These defects continue toexpand and evolve in the common effect of temperature field, electromagnetic fieldand stress field, leading to the electronic device failure. Therefore, to improve thereliability of electronic package, the defects should be detected timely, the applicationof infrared thermography is particularly important for the fast and efficientlynon-destructive testing (NDT).The three-dimensional geometric models were established using the finiteelement analysis software ABAQUS，to simulate the NDT of infrared thermography.Besides the surface temperature field and the surface temperature difference trendover time of the model with different defects in the heating process were obtained，theinfluence for the detection with the size of defect or heat flux was summarized. Thesimulation results provide basis and reference for the experimental methods to detectdefects by infrared thermography.The infrared camera SC7000was used to record the thermal characteristicchanges of LQFP128L by active imaging in general room environment. The quality ofinfrared images was improved through Matlab and the information of surfacecharacteristics was extracted and recognized. With the Comparison and analysis to theresults of the scan and ultrasonic microscopy, the feasibility of NDT with Infraredthermography to detect defects in electronic package was verified.The experimental samples containing different size or depth of defect were madewith mold compound and copper. The data such as the maximum surface temperaturedifference, the best sensitivity, the peak contrast time and the initial deviation timewere acquired. Thus, the impact of the size and depth for the defect and the limitdepth of NDT can be known. Combined the mathematical relationship between thegeometric characteristics of defect and the thermal characteristics with the depth oftheoretical formula, the equivalent diameter, thickness and depth of defect wereanalyzed and calculated, in order to achieve the quantitative identification of defect.