Development of ruggedized timer and temperature sensor packaging for 300°C/30kpsi downhole environment

While the advantages of high temperature electronics in the form of hermetic ceramic packaging are numerous, their deployments are being limited by the maximum environmental pressure. Literature [1] has shown that to withstand 30kpsi pressure for instance, a flat ceramic lid of at least 3mm will be required for a cavity size of 10.16mm × 10.16mm. Lid thickness will have to increase if the cavity size is increased. However, by filling the cavity with high temperature endurable material, thickness requirement can be eliminated from consideration, maintaining low package profile [2]. The approach has been demonstrated through a timer / temperature sensor circuitry embedded in a 31.75mm × 10.92mm cavity and successfully passed a combined HPHT of 30kpsi and 300°C until the end of targeted 200 hours.