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US 5,910,699 AGranted
Method of manufacturing a composite substrate and a piezoelectric device using the substrate
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsAkihiko Namba, Tetsuyoshi Ogura, Yoshihiro Tomita, Kazuo Eda
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Abstract
A method of manufacturing a composite substrate and the composite substrate manufactured thereby wherein surfaces of first and second substrates having different thermal expansion coefficients are mirror finished and layered on each other. A first heat treatment is applied after which a part of the second substrate is removed to a depth sufficient to expose the first substrate. A final second heat treatment directly bonds the substrates.
Claims10
A piezoelectric device comprising:
- a piezoelectric substrate composed of piezoelectric material and including excitation electrodes on a portion thereof;
- and
- a supporting substrate bonded by one of covalent bonding and ionic bonding to a bonding portion provided on a part of said piezoelectric substrate,
- wherein the crystal structure of the piezoelectric substrate at the portion having the excitation electrodes is different from the crystal structure of the piezoelectric substrate at the bonding portion.
1 more element
A piezoelectric device comprising:
- a piezoelectric substrate composed of piezoelectric material and including electrodes on a portion thereof;
- and
- a supporting substrate bonded by one of covalent bonding and ionic bonding to a bonding portion provided on a part of said piezoelectric substrate,
- wherein the bonding portion is of a substantial rectangular shape;
- a thermal expansion coefficient of said piezoelectric substrate in the direction of a longer side of the rectangular shape is different from a thermal expansion coefficient of said piezoelectric substrate in the direction of a shorter side of the rectangular shape;
- and
- the difference between the thermal expansion coefficient of said piezoelectric substrate in the longer side direction of the rectangular shape and the thermal expansion coefficient of said supporting substrate is less than the difference between the thermal expansion coefficient of said piezoelectric substrate in the shorter side direction of the rectangular shape and the thermal expansion coefficient of said supporting substrate.
4 more elements
Dependencies are inferred from the claim text.