Reliability improvement of epoxy molding compound on T0252

The delamination of epoxy molding compound (EMC) on TO252 after JEDEC level 3 and 260c reflow was studied from 3 factors as epoxy resin, phenol hardeners, and filler content. It indicated that when the epoxy resin is mixed of biphenyl and EOCN type, phenol resin is the new type with the structure as Fig.l, filler content as 84%, the resulting epoxy molding compound exhibited the same performance as the control: no delamination after JEDEC level 3 and 260°C reflow. The typical properties of EMC such as modulus, water absorption and viscosity were tested by Dynamic Mechanical Analysis (DMA), pressure cook test (PCT) 24hours and capillary rheometer CFT500D. The testing results disclosed that the EMC with biphenyl type epoxy and the fig. 1 type showed lower storage modulus at 260°C and better delamination performance; While EMC with higher filler content of 86% showed the lowest water absorption, however the delamination performance was not improved significantly. In the testing EMC system, modulus played more important role than water absorption in the delamination performance for TO252 package.