Patent ID: 9646874
Date: 2017-05-09
CPC Classifications: B81B,H01L,H03H

Claim:
1. A thermally-isolated integrated circuit assembly formed on a silicon-based substrate having a back face that is free of etched openings, comprising: a piezoelectric resonator; a body of dielectric material; a support bar; a CMOS integrated circuit; a base layer of silicon; a base layer of silicon oxide above and contiguous to the silicon base layer; and an active silicon layer above and contiguous to the silicon oxide base layer; wherein: the CMOS integrated circuit comprises at least one device defined in the active silicon layer and further comprises a plurality of metallization layers that overlie the active silicon layer and are embedded in an interlayer dielectric; a lower cavity is defined within the silicon base layer; the body of dielectric material is suspended over the lower cavity by the support bar; the CMOS integrated circuit is encased on top, bottom, and all sides by the body of dielectric material; an upper cavity is defined in the top of the body of dielectric material; the piezoelectric resonator is suspended over the upper cavity and electrically connected to the CMOS integrated circuit through vertical electrical conductors extending within the body of dielectric material; the upper and lower cavities are interconnected by trenches in the body of dielectric material; and the support bar is formed in the silicon-based substrate to provide physical contact between the silicon-based substrate and the body of dielectric material.