Fracture Strength Improvement of Semiconductor Devices Encapsulated Using a Lead-on-Chip Packaging Technique

摘要

This article describes how the flexural displacement-induced fracture strength of a lead-on-chip (LOC) package is influenced by a density change in SiC-fillers embedded in a package body of 60 wt% to 80 wt% and temperature variation of 25 °C to 300 °C. The experimental results show that the fracture strength of LOC packages increases with an enhanced filler density at a temperature lower than 150 °C, while it is not affected by a filler density change at a temperature higher than 200 °C. Micro-structural examination indicates that the fracture results from crack initiation at the bottom surface of the plastic package body at a temperature lower than 150 °C. On the other hand, at a temperature higher than 200 °C, delamination between the silicon device and the plastic package body takes place first, and then chip cracking follows without package body damage. Thus, at the temperatures higher than 200 °C, enhanced filler density in a package body does not contribute to the improvement of package fracture strength. Furthermore, this work shows that regardless of filler density variation, the fracture strength of the packages having the silicon devices with grinding-induced scratch marks is lower than that with no scratch marks at a temperature higher than 200 °C.