Lidded vs. Lidless: A Thermal Study

In the recent years, lidless (bare) die packaging starts to appear in the high power applications with a large die size, complementing the conventional lidded packaging. Given the vast parameters’ space of the lidded vs. lidless designs, a systematic study is necessary to develop a clear and practical design recommendations. In this work, an analytical study is conducted to assess the sensitivity of the thermal spreading resistance (TSR) and the total junction-to-ambient thermal resistance (R_ja) on various parameters for a typical lidded (LD) and lidless (LL) package configuration. Useful findings and design guidance are provided.