Quartz crystal unit and method for fabricating same
AssigneeNihon Dempa Kogyo Co., Ltd.
InventorsMasahiro Yoshimatsu, Mitoshi Umeki
Life of this patent
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Abstract
A crystal blank for use as a vibrator and a reinforcing plate are joined by direct bonding without an interposed adhesive to form a quartz crystal unit. Through-holes are provided in the reinforcing plate by etching with hydrofluoric acid. Excitation electrodes are formed on both major surfaces of the quartz crystal blank corresponding to the through-holes. An AT-cut quartz crystal plate is preferably used as the crystal blank. The reinforcing plate may be, for example, a Z-cut quartz crystal plate, an AT-cut quartz crystal plate, or a glass plate.
Claims19
A crystal unit comprising a crystal blank for a vibrator and a reinforcing plate that includes a through-hole, said crystal blank and said reinforcing plate being joined by direct bonding.
A method of fabricating a crystal unit, comprising steps of:
- providing a through-hole corresponding to a formation location of each crystal unit in a first wafer that corresponds to a plurality of said crystal units;
- directly bonding said first wafer in which said through-holes have been formed to a second wafer constituted by a quartz crystal plate to obtain a laminate;
- forming excitation electrodes that are provided on both major surfaces of said second wafer corresponding to the formation location of each of said crystal units, and extending electrodes that extend away from said excitation electrodes, respectively;
- and
- dividing said laminate into individual crystal units.
A method of fabricating a crystal unit, comprising steps of:
- directly bonding a first wafer that corresponds to a plurality of crystal units to a second wafer that is constituted by a quartz crystal plate to obtain a laminate;
- forming holes that correspond to a formation location of each of said crystal units in said laminate from the major surface of said first wafer that is exposed as far as an interface of said first wafer and said second wafer;
- forming excitation electrodes that are provided on both major surfaces of said second wafer that correspond to the formation location of each of said crystal units, and extending electrodes that extend away from excitation electrodes, respectively;
- and
- dividing said laminate into individual crystal units.
Dependencies are inferred from the claim text.