Electrical and Reliability Performance of Molded Leadless Package for High-voltage Application

Abstract

This paper investigates the influence on electrical and reliability performance of molded leadless package for high-voltage power integrated circuit application. Semiconductor devices are mostly encapsulated by using epoxy molding compounds which act as protection for the ICs from damage to the harsh environment. Quad Flat No Lead was selected since the application requirement for compact AC to DC portable adapter charger and more input and output pin. High-voltage package was designed based on the IPC-2221 standard specification and creepage distance was calculated under external component lead, uncoated. Two epoxy molding compounds were used namely as type A and B. Key properties of EMCs were identified such as ionic content, glass transition temperature and volume resistivity. The electrical tested at room temperature on high-voltage leakage current at 700V showed EMC B has no failure compared with EMC A. On top of that, electrical parametric distribution showed that the Cpk of EMC B was extremely robust compared with EMC A. Reliability test was conducted for high temperature operating life test at 115˚C and EMC B was passed up to 1000hours while EMC A was failed. Meanwhile, High Temperature Storage Life test at 150˚C and Temperature Humidity Bias Test at condition 85˚C, 85% relative humidity showed that EMC B was passed for 1000hours but EMC A was failed at 168hours. However, both compounds A and B were passed delamination criteria tested by scanning acoustic tomography technique before and after subjected to moisture sensitivity level 1.