2023 article

Thermal Cycling and Fatigue Life Analysis of a Laterally Conducting GaN-based Power Package


By: P. Zaghari n, S. Sinha n, J. Ryu n, P. Franzon n & D. Hopkins n

co-author countries: United States of America 🇺🇸
author keywords: GaN power module; thermal reliability; mechanical stress; fatigue life prediction; finite element analysis
Source: Web Of Science
Added: August 14, 2023

Thermal reliability is a critical factor in ensuring the performance and efficiency of GaN-based electronic devices. In this paper, the fatigue life assessment of a laterally conducting GaN power package that uses a two-solder hierarchy of SAC305 and Sn63/Pb37 on a 120μm thick dielectric for device attach was conducted using an FEA. The double-sided package structure also introduced thick Cu as integrated baseplate layers for mechanical mounting into higher packaging levels while providing surfaces for double-sided cooling. The internal structure varied spacer thicknesses for planarization and inclusion of package-integrated decoupling capacitors. The solder materials were simulated by using the Anand viscoplastic constitutive model. Coffin-Manson, Engelmaier, and Solomon empirical strain-based models were utilized to predict the cyclic life of the package. Based on the results, the critical solder joint location was predicted in the Sn63/Pb37 solder layer between the GaN and Cu spacer, with a strain range of 0.02797. The worst-case life prediction for the module was 150 cycles using the Coffin-Manson model.