Patent ID: 8704315
Filing Date: 2014-04-22
Classification: B81B,B81C,Y10T

Abstract:
1. A method for making a CMOS integrated micromechanical device, the method comprising: a.) selecting a standard CMOS foundry fabrication process, the standard CMOS foundry fabrication process being characterized by a predetermined layer map and a predetermined set of fabrication rules; b.) providing a semiconductor substrate in accordance with the predetermined layer map and the predetermined set of fabrication rules; c.) forming a layer of field oxide material over the semiconductor substrate in accordance with the predetermined layer map and the predetermined set of fabrication rules, the field oxide material forming a double-tapered profile around a predefined perimeter; d.) conformally coating the field oxide material with at least one layer of thin-film material to form a film-stack in accordance with the predetermined layer map and the predetermined set of fabrication rules, the film stack being configured as a MEMS resonator device; e.) forming CMOS electronics elements in accordance with the predetermined layer map and the predetermined set of fabrication rules, the steps c-e not being necessarily performed sequentially, the steps c-e being performed during the standard CMOS foundry fabrication process; and f.) removing the field oxide layer or an interpoly oxide layer to form a MEMS resonator device after steps c-e are completed, the step of removing being configured to release the MEMS resonator device such that at least a portion of the MEMS resonator device flexes upwardly and away from the semiconductor substrate in conformance with the double-tapered profile, the MEMS resonator device being characterized by a predetermined mechanical resonance frequency.