Over-mold packaging for wide band-gap semiconductor devices

摘要

A transistor package includes a lead frame and a gallium nitride (GaN) transistor attached to the lead frame. The lead frame and the GaN transistor are surrounded by an over-mold with a glass transition temperature greater than about 135° C. and a flexural modulus less than about 20 GPa. Using an over-mold with a glass transition temperature greater than about 135° C. and a flexural modulus less than about 20 GPa allows the over-mold to handle the heat produced by the GaN transistor while preventing damage to the GaN transistor due to thermal expansion and/or contraction of the over-mold.

主权项

1. A transistor package comprising:
a lead frame; a wide band-gap semiconductor device attached to the lead frame using a die attach material with a bulk thermal conductivity greater than about 40 W/m-K and less than about 200 W/m-K and a flexural modulus less than about 20 GPa, and an over-mold that is molded at least part way around the lead frame and that substantially surrounds the wide band-gap semiconductor device, the over-mold having a glass transition temperature greater than about 135° C. and a flexural modulus less than about 20 GPa, wherein the over-mold has a thermal coefficient of expansion less than about 50 ppm/° C. at temperatures above the glass transition temperature and a coefficient of thermal expansion less than 18 ppm/° C. at temperatures below the glass transition temperature.