Murata Manufacturing Co., Ltd.

Masanobu Watanabe

Kazuhiro Inoue

Kenji Sakaguchi

Osamu Nakagawara

Masahiko Saeki

Mitsushi Takatori

A surface acoustic wave device includes a surface acoustic wave element, a packaging case, and a packaging electrode. The surface acoustic wave element has a piezoelectric substrate, an interdigital transducer, an electrode pad, an intermediate electrode, an upper electrode, and a bump electrode. The intermediate electrode is preferably made of NiCr including about 15 to about 30 weight percent of Cr. The electrode pad and upper electrode are made of Al. The bump electrode is press-bonded to the packaging electrode with an ultrasonic wave or heat applied to the bump electrode. The resulting surface acoustic wave device has excellent characteristics and the surface acoustic wave element is not removed or peeled from the packaging case during a drop test.

Surface acoustic wave element, surface acoustic wave device using the same, and method for manufacturing surface acoustic wave element and surface acoustic wave device

A surface acoustic wave element includes multilayer electrodes having much higher electric power durability compared to conventional surface acoustic wave elements. The multilayer electrodes are prepared by forming, on a piezoelectric substrate, a Ti base electrode film that improves the orientation characteristics of the multilayer electrodes, an Al-type electrode film, an electrode film having a diffusive material that can easily diffuse into the grain boundary of the Al electrode film, and then an Al electrode film, in this order.

Surface acoustic wave element

A surface acoustic wave device includes a piezoelectric substrate made of a LiNO or LiTaO single crystal, and an electrode having power endurance. After a damaged layer formed on a surface of the piezoelectric substrate is removed, an under-electrode layer including at least one of Ti and Cr as a main component is formed by a vacuum deposition process at a temperature of about 100&deg; C. or less, and an Al electrode layer including Al or an Al main component is then formed on the under-electrode layer. The Al electrode layer has a twin crystal structure in which the Al crystal is oriented in a desired direction such that the (111) crystal plane of Al substantially coincides with the Z crystal direction of the piezoelectric substrate.

Surface acoustic wave device with improved electrode

A method for producing a surface acoustic wave device includes the steps of forming a resist pattern corresponding to an interdigital electrodes transducer onto a piezoelectric substrate; forming a first electrode layer comprising elemental Ti or a Ti-based alloy onto the piezoelectric substrate and the resist pattern R; forming a second electrode layer which comprises elemental Cu or an Al-based alloy containing at least 2% by weight of Cu (this layer may have a multilayered structure) onto the first electrode layer; and removing both the resist pattern R and unnecessary parts, if any, of the first electrode layer 31 and the second electrode layer to simultaneously pattern the first electrode layer and the second electrode layer. A surface acoustic wave device is constructed according to the above method.

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Kanazawa, Japan

Masanobu Watanabe