Patent ID: 7528523

Claim:
A surface acoustic wave device comprising: an IDT electrode formed at a main surface of a piezoelectric substrate; an extraction electrode extracted from the IDT electrode; a surface acoustic wave chip having a metal junction formed along a periphery of the main surface of the piezoelectric substrate; a cover substrate made of an insulting material and having a first surface and a second surface opposing the first surface; a contact electrode connecting to the extraction electrode formed at the first surface of the cover substrate; and an external electrode formed at the second surface of the cover substrate, the cover substrate having a through-hole electrode for connecting the contact electrode to the external electrode, the IDT electrode and the extraction electrode being disposed in a space that is hermetically sealed by bonding the metal junction of the surface acoustic wave chip to the first surface of the cover substrate, an auxiliary section being formed on the main surface of the piezoelectric substrate within the space, and having a height to prevent the cover substrate from coming in contact with the IDT electrode even in the case of distortion in the piezoelectric substrate or the cover substrate, and the auxiliary section being a metal film formed in a longitudinal direction of the IDT electrode, near but without contact with the IDT electrode.