Surface acoustic wave device and electronic component comprising it
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMitsuhiro Furukawa, Kiyoharu Yamashita, Kazushi Nishida, Hiroshi Kurotake
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Abstract
In a surface acoustic wave device, a common portion and a strip portion of a reflector electrode are partially cut off to increase a space between the electrodes. The increase of the space between the electrodes reduces the influence of the amount of charges and the influence of an unbalance between the amounts of charges in etching of a metallic film, thereby preventing the electrodes from having a curved shape in section. Consequently, the surface acoustic wave device has a reduced propagation loss.
Claims21
A surface acoustic wave device comprising:
- a piezoelectric substrate;
- an interdigital electrode provided on said piezoelectric substrate;
- and
- a reflector electrode provided on said piezoelectric substrate, said reflector electrode including a common portion and a strip portion,
- wherein said common portion and said strip portion of said reflector electrode have respective cut portions adjacent to said interdigital electrode formed therein.
A unit comprising:
- a base;
- a surface acoustic wave device disposed on said base, said surface acoustic wave device including
- a piezoelectric substrate,
- an interdigital electrode provided on said piezoelectric substrate, and
- a reflector electrode provided on said piezoelectric substrate, said reflector electrode including a common portion and a strip portion, said common portion and said strip portion having respective cut portions adjacent to said interdigital electrode;
- one of a bump and a wire for electrically coupling said base to said surface acoustic wave device;
- and
- a cover for sealing said surface acoustic wave device.
A method of manufacturing a surface acoustic wave device, comprising the steps of:
- forming a plurality of interdigital electrodes on a piezoelectric substrate wafer;
- forming a plurality of reflector electrodes on the piezoelectric substrate wafer, the plurality of reflector electrodes each including a common portion and a strip portion having respective cut portions formed therein adjacent to the interdigital electrode;
- and
- dividing the piezoelectric substrate wafer to obtain a plurality of surface acoustic wave devices each including at least one of the plurality of interdigital electrodes and at least one of the plurality of reflector electrodes, wherein an amount of the cut portion of a surface acoustic wave device of the plurality of surface acoustic wave devices that is located at a central portion of the piezoelectric substrate wafer is smaller than a surface acoustic wave device of the plurality of surface acoustic wave devices that is located in an outer portion of the wafer.
Dependencies are inferred from the claim text.