Surface acoustic wave element, surface acoustic wave device, surface acoustic wave duplexer, and method of manufacturing surface acoustic wave element

摘要

A surface acoustic wave element (12) includes a thin film electrode composed of monocrystal aluminum disposed on a piezoelectric substrate. At least one metal of Cu, Ta, W, and Ti is segregated in the thin film electrode (18) composed of monocrystal aluminum. In this surface acoustic wave element (12), segregation of Cu or the like occurs in the thin film electrode (18). Such segregation is effective to reduce the occurrence of cracks on the piezoelectric substrate (28) during ultrasonic wave connection for flip chip mounting. That is, because the occurrence of cracks on the piezoelectric substrate (28) is reduced, tolerance against the ultrasonic vibration is advantageously improved in the surface acoustic wave element (12).