This paper describes a 60 GHz high-Q cavity resonator etched in silicon. This cavity is flip-chip bonded to an MCM-D HRSi substrate containing the planar feed structure. The quality factor of the resonator without feed as predicted by HFSS is 1506 at 60 GHz. Substrate mode excitation by the feed is suppressed by using a semi-shielded cavity underneath the coupling slot. Design data together with a fitted lumped element model are presented for the resonator with feed and show a simulated Q of 1220.