Sixty Earth-Day Test of a Prototype Pt/HTCC Alumina Package in a Simulated Venus Environment

This article presents experimental results of a prototype high-temperature cofired ceramic (HTCC) package with Au/Pt metallization in a three-phase harsh environment test that culminated with a 60-d demonstration in a simulated Venus surface environment consisting of a 465°C corrosive atmosphere at 90 bar pressure. The prototype package is based on a previously developed and reported HTCC package successfully tested with multiple analog and digital silicon carbide high-temperature semiconductor integrated circuits in 500°C Earth air ambient for more than 10,000 hours, and short-term tested at temperatures above 800°C. The three-phase harsh environment test started with 48 h in 465°C Earth air, followed by 48 h in 465°C nitrogen at 90 bar pressure and 1,400 h in a simulated Venus surface environment of 465°C corrosive atmosphere at 90 bar. In addition to in situ electrical tests in a three-phase harsh environment and posttest electrical diagnosis, initial posttest analysis of the package materials and surfaces was performed to assess the stability of the packaging materials in the testing environments, as well as the surface conditions after the test. The test in the simulated Venus environment was implemented in the NASA Glenn Extreme Environment Rig. The results of this study suggest that an effective encapsulation of areas of surface metallization and vicinities may help improve the long-term electrical performance of an HTCC alumina packaging system in a Venus environment.