Analysis of Experimental Results and Theoretical Study of Secondary Molding Process of Optocoupler
Aiming at the problem that the research on the influence of secondary plasticizing process on the performance of photocoupler is still imperfect,this paper carries out experimental and finite element simulation research on the effect of photocou-pler encapsulation of secondary plasticizing in MSL1 level environment.Using ultrasonic scanning microscope and other experimental equipment,we analyze the delamination of photocoupler encapsulated devices under four processes of reflow soldering,internal dis-pensing,epoxy encapsulant and plasma cleaning,test the current transfer ratio,and study the effect of epoxy encapsulant stress pa-rameter on delamination,so as to optimize the conditions of the secondary plastic encapsulation process.The results show that the reflow soldering peak temperature set at Tp=245℃to Tp=250℃can improve the delamination problem;the chip adhesive height a-bove 0.4 mm and below 0.3 mm will cause serious delamination of the optocoupler;Using the plastic sealing material matching ther-mal stress parameters and increasing the plasma cleaning process before the secondary plastic sealing,the cleaning power is set to 300 W and the cleaning time is 15 s,which is an effective measure to improve the optocoupler package.
万方数据
维普
