Surface acoustic wave element, method for producing the same and surface acoustic wave device using the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsKeiji Onishi, Hiroki Sato, Yoshihiro Tomita
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Abstract
A surface acoustic wave element includes a laminated substrate where a first substrate made of a piezoelectric material is laminated over a second substrate made of a material different from that of the first substrate, and at least one pair of comb-shaped electrodes formed on one main plane of the first substrate. A step or a notch is formed on the periphery of the laminated substrate on the side of the first substrate.
Claims14
A surface acoustic wave element comprising a laminated substrate where a first substrate made of a piezoelectric material is laminated over a second substrate made of a material different from that of the first substrate,
- comprising at least one pair of comb-shaped electrodes for exciting a surface acoustic wave, which is formed on one main plane of the first substrate,
- wherein a step or a notch is formed on a periphery of the laminated substrate on a side of the first substrate, the step or notch being formed from the first substrate into the second substrate,
- the second substrate has a thermal expansion coefficient smaller than a thermal expansion coefficient of the first substrate in a propagation direction of the surface acoustic wave, and
- a thickness of the first substrate is in a range of 5 μm to 100 μm, and a thickness of the second substrate is in a range of 200 μm to 400 μm.
A method for producing a surface acoustic wave element, comprising:
- (a) forming a laminated substrate where a first substrate made of a piezoelectric material and provided with a pair of comb-link electrodes on one main plane thereof is laminated over a second substrate made of a material different from that of the first substrate;
- (b) forming a groove on a portion around the comb-shaped electrodes of the laminated substrate, wherein the portion removed when the groove is formed forms a step or notch, said step or notch being formed from the first substrate into the second substrate;
- and
- (c) grinding at an approximately central portion of the groove on the laminated substrate in a width narrower than that of the groove so as to cut the laminated substrate.
Dependencies are inferred from the claim text.