Seiko Epson Corporation

Epson Toyocom Corporation

Yuji Mitsui

Koichi Morozumi

Takuya Owaki

Osamu Iwamoto

Yuzuru Yoshizawa

An SH wave type surface acoustic wave device includes a piezoelectric substrate and an IDT electrode provided on the piezoelectric substrate and constituted of Al or an alloy mainly containing Al and that uses a SH wave as an excitation wave. The piezoelectric substrate is a crystal plate in which a cut angle &#x3b8; of a rotary Y cut quartz substrate is set in a range of &#x2212;64.0&#xb0;&#x3c;&#x3b8;&#x3c;&#x2212;49.3&#xb0; in a counter-clockwise direction from a crystal axis Z and in which a surface acoustic wave propagation direction is set at 90&#xb0;&#xb1;5&#xb0; with respect to a crystal axis X. An electrode film thickness H/&#x3bb; standardized by a wavelength of the IDT electrode is 0.04&#x3c;H/&#x3bb;&#x3c;0.12, where &#x3bb; is a wavelength of the surface acoustic wave to be excited, and a main surface of the piezoelectric substrate is etched by a thickness of 0.002 &#x3bc;m or more.

Surface acoustic wave device, module device, oscillation circuit, and method for manufacturing surface acoustic wave device

A method for manufacturing a surface acoustic wave element including: forming a conductive film on a surface of a piezoelectric substrate; forming a photoresist film on the conductive film; printing a pattern by exposing and developing the pattern, which is originally provided on a photomask, onto the photoresist film by reduced projection; forming an electrode of a surface acoustic wave element by etching the conductive film using the patterned photoresist film as a mask; measuring a resonant frequency of the surface acoustic wave element formed on the piezoelectric substrate; calculating an anodic oxidation voltage based on an amount of anodic oxidation of the electrode that is calculated in advance from the measured resonant frequency and a preset target resonant frequency; and performing anodic oxidation based on the anodic oxidation voltage calculated in the voltage calculation step and finishing anodic oxidation after detecting an end-point of oxidation reaction of the electrode.

Method for manufacturing surface acoustic wave element, as well as surface acoustic wave element manufactured by the same method

A surface acoustic wave device is provided having a substrate made of quartz, a pair of inter digital transducer-shaped electrodes made of an aluminum layer, an electrode pad, and a pair of lattice-shaped reflectors made of the same material as the electrode. The crystal structure of the aluminum layer composing the electrode is a twin crystal structure, where crystal grains of the (&minus;1 1 1) plane and the (0 0 2) plane and crystal grains of the (1 &minus;1 &minus;1) plane and the (0 0 &minus;2) plane are in a twin crystal relationship with the (&minus;1 1 &minus;1) plane and the (1 &minus;1 1) plane of aluminum as the twin boundaries. Also, the &lcub;1 1 1&rcub; plane of the aluminum layer is oriented to an 8&deg; inclination relative to the &lcub;0 1 0&rcub; plane of quartz composing the substrate.

Surface acoustic wave device

A surface acoustic wave device is provided having a substrate made of quartz, a pair of inter digital transducer-shape electrode made of an aluminum layer, an electrode pad, and a pair of lattice-shaped reflectors made of the same material as the electrode. The crystal structure of the aluminum layer composing the electrode is a twin crystal structure, where crystal grains of the (&minus;1 1 1) plane and the (0 0 2) plane and crystal grains of the (1 &minus;1 &minus;1) plane and the (0 0 &minus;2) plane are in a twin crystal relationship with the (&minus;1 1 &minus;1) plane and the (1 &minus;1 1) plane of aluminum as the twin boundaries. Also, the &lcub;1 1 1&rcub; plane of the aluminum layer is oriented to an 8&deg; inclination relative to the &lcub;0 1 0&rcub; plane of quartz composing the substrate.

Growing community of inventors

Chino, Japan

Yuji Mitsui