A LOW TEMPERATURE BI-CMOS COMPATIBLE PROCESS FORMEMS RF RESONATORS AND FILTERS

摘要

A low temperature, Bi-CMOS compatible process for thefabrication of MEMS resonators and filters has been developed.These devices hold the promise of reducing cost and powerrequirements in IC’s for communications applications. Thedevices were fabricated on 200mm wafers in standard productiontools using materials and processes routinely employed for on-chipinterconnect in a typical CMOS line. The maximum processingtemperature for the MEMS devices is 400C.Simple cantilever and fixed beam structures were fabricatedand tested. Un-encapsulated devices were measured in a lowpressuresystem to determine frequency response and quality factor(Q). Devices were typically actuated with DC biases between 4-5V; useful tuning range is from ~3-7 V, corresponding to a 1% shiftin frequency for the devices measured here. Frequency responsesfrom 3-45 MHz have been recorded. Under vacuum, averagedevice Q’s were around 2000, although values above 10,000 havebeen measured. The devices maintain peak Q up to a pressure ofapproximately 100 mT. Temperature effects were also studied.