Patent ID: 7176599

Claim:
A surface acoustic wave device comprising: interdigital transducers; first electrode pads that are connected to the interdigital transducers through wire patterns; a piezoelectric substrate on which the interdigital transducers, the first electrode pads, and the wire patterns, are formed, at least one of the first electrode pads not being connected to a ground pattern, and the piezoelectric substrate having a conductivity in the range of 10 −12 /Ω·cm to 10 −6 /Ω·cm; a substrate on which second electrode pads to be connected to the first electrode pads are formed, wherein: the piezoelectric substrate has a first layer that surrounds at least the interdigital transducers and is made of a metal material identical to that of the first and second electrode pads; the substrate has a second layer that is formed in a region corresponding to the first layer, includes a through hole formed therein for an external connection and wherein the substrate for the second layer is made of said metal material; and the piezoelectric substrate and the substrate are bonded to each other by joining the first layer and the second layer to each other.