High-temperature endurable encapsulation material

The accomplishment of fully functional high-pressure high-temperature (HPHT) well is possible only, when the packaging and interconnections in the well logging equipments can survive at higher temperatures. Currently, there are numerous choices for substrate materials and interconnection materials. However, there are hardly any encapsulation materials that can endure at 300°C. Thus, the limiting factor for the evaluation and monitoring of HPHT wells is; the availability of high-temperature endurable encapsulation material. In this paper, the endurability of three prospective candidates for high-temperature encapsulation have been characterized and reported. The three prospective candidates are benzocyclobutene (BCB), ceramic filled cyanate ester and quartz filled cyanate ester. The high-temperature endurability has been evaluated in this work by high-temperature storage at 300°C up to 500 hours. Adhesion strength of these prospective candidates with the alumina ceramic substrate and the Si die was verified by room shear testing and hot shear testing. It has been determined that the quartz filled cyanate ester could comply with the minimum indispensable requirement for this application, when sandwiched between alumina ceramic substrates, despite the loss of strength during long-term thermal aging at 300°C. The material degradation has been studied in this work, using thermo-gravimetric analysis.