Surface acoustic wave device and method for fabricating the same
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorKoji Morishima
Life of this patent
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Abstract
A surface acoustic wave device that is small, lightweight and highly reliable, and protects its functional portion. The surface acoustic wave device has surface acoustic wave elements mounted on a circuit substrate. Each surface acoustic wave element includes a frame-like first insulating film furnished to surround functional portions on a chip, and a lid-like second insulating film deposited on the first insulating film so as to cover driving electrodes and surface wave propagation paths of the functional portions, while securing a hollow portion over the functional portions.
Claims4
A surface acoustic wave device, comprising:
- a circuit substrate;
- a plurality of terminals formed on a surface of said circuit substrate;
- a piezoelectric substrate having a principal plane facing said surface of said circuit substrate;
- a functional portion formed on said principal plane of said piezoelectric substrate and which has driving electrodes for driving surface waves in a predetermined direction over a surface of said piezoelectric substrate;
- a plurality of bump electrodes formed on said principal plane of said piezoelectric substrate so as to be electrically connected to said functional portion, and projecting from said principal plane of said piezoelectric substrate to electrically contact said plurality of terminals;
- a first insulating film formed on said principal plane of said piezoelectric substrate except for areas over said functional portion and said bump electrodes;
- a second insulating film formed on said first insulating film except for areas over said bump electrodes, to thereby form a protective space over said functional portion;
- and
- an anisotropic conductor film formed between said circuit substrate and said second insulating film, said anisotropic conductor film extending over an area at least corresponding to said piezoelectric substrate and contacting said plurality of bump electrodes, said second insulating film, and said surface of said circuit substrate including said plurality of terminals.
A surface acoustic wave device, comprising:
- a circuit substrate;
- a plurality of terminals formed on a surface of said circuit substrate;
- a piezoelectric substrate having a principal plane facing said surface of said circuit substrate;
- a functional portion formed on said principal plane of said piezoelectric substrate and which has driving electrodes for driving surface waves in a predetermined direction over a surface of said piezoelectric substrate;
- a plurality of bump electrodes formed on said principal plane of said piezoelectric substrate so as to be electrically connected to said functional portion, and projecting from said principal plane of said piezoelectric substrate to electrically contact said plurality of terminals;
- a first insulating film formed on said principal plane of said piezoelectric substrate except for areas over said functional portion and said bump electrodes;
- and
- an anisotropic conductor film formed on said circuit substrate and extending over an area at least corresponding to said piezoelectric substrate and contacting said plurality of bump electrodes and said plurality of terminals;
- wherein
- a hollow portion for protectively enveloping said functional portion is formed by said first insulating film and said anisotropic conductor film.
Dependencies are inferred from the claim text.