Thin-Film Flip-Chip Assembly for High- Temperature Geothermal Application

A thin-film multichip module technology has been developed and evaluated for packaging high-temperature (300 °C) geothermal well instrumentation. Since a measurement-while-drilling tool is exposed to a combination of high-temperature and shock/vibration loading, flip-chip technology was selected to avoid vibration-related problems with bond wires. Thermocompression flip-chip bonding was characterized in thermal aging, thermal cycling, and thermal shock/vibration tests. Three digital circuit boards were fabricated and electrical characteristics of the digital circuit boards were evaluated. The experimental results show that thin-film substrates combined with flip-chip assembly are a viable approach for fabrication of digital circuit boards for use in extreme environments.