A method for forming a vibrating micromechanical structure having a single
crystal silicon (SCS) micromechanical resonator formed using a two-wafer
process, including either a Silicon-on-insulator (SOI) or insulating base
and resonator wafers, wherein resonator anchors, capacitive air gap,
isolation trenches, and alignment marks are micromachined in an active
layer of the base wafer; the active layer of the resonator wafer is
bonded directly to the active layer of the base wafer; the handle and
dielectric layers of the resonator wafer are removed; windows are opened
in the active layer of the resonator wafer; masking the active layer of
the resonator wafer with photoresist; a SCS resonator is machined in the
active layer of the resonator wafer using silicon dry etch micromachining
technology; and the photoresist is subsequently dry stripped. A patterned
SCS cover is bonded to the resonator wafer resulting in hermetically
sealed chip scale wafer level vacuum packaged devices.