Quartz-based mems resonators and methods of fabricating same

Abstract

A quart resonator for use in lower frequency applications (typically lower than the higher end of the UHF spectrum) where relatively thick quartz members, having a thickness greater than ten microns, are called for. A method for fabricating same resonator includes providing a first quart substrate; thinning the first quartz substrate to a desired thickness; forming a metallic etch stop on a portion of a first major surface of the first quartz substrate; adhesively attaching the first major surface of the first quartz substrate with the metallic etch stop formed thereon to a second quartz substrate using a temporary adhesive; etching a via though the first quartz substrate to the etch stop; forming a metal electrode on a second major surface of the first quartz substrate, the metal electrode penetrating the via in the first quartz substrate to make ohmic contact with the metallic etch stop; bonding the metal electrode formed on the second major surface of the first quartz substrate to a pad formed on a substrate bearing oscillator drive circuitry to form a bond there between; and dissolving the temporary adhesive to thereby release the second quartz substrate from the substrate bearing oscillator drive circuitry and a portion of the first quartz substrate bonded thereto via the bond formed between the metal electrode formed on the second major surface of the first quartz substrate to and the pad formed on the substrate bearing oscillator drive circuitry.