AND FABRICATION OF RF MEMS SHUNT SWITCHES WITH HIGH ISOLATION
X.L. EVANS, S.J.N. MITCHELL, P.V. RAINEY, H.S. GAMBLE, N.B.
BUCHANAN, V.F. FUSCO
This paper presents details of a new, fast and economical method to
fabricate radio frequency microelectromechanical (RF MEMS) capacitive
switches. Coplanar waveguide (CPW) lines are made with sputtered tungsten.
A high quality dielectric layer of silicon nitride is deposited by low
pressure chemical vapour deposition (LPCVD) instead of the traditional
plasma enhanced CVD (PECVD) method. A new release technique is employed,
whereby the sacrificial layer (thick photoresist AZ9260) is removed by
fuming nitric within 30 seconds instead of by long duration plasma
etching[3, 4]. Only 3 masks are required in the fabrication of the switch.
The technology provides a new platform to fabricate RF MEMS switches.