Patent ID: 7400219

Claim:
A surface acoustic wave device including at least an IC region and a surface acoustic wave element region in a semiconductor substrate and formed as a single chip, comprising: in the IC region, at least, a semiconductor element layer having a semiconductor element and an element insulating film formed to cover the semiconductor element and extending to the surface acoustic wave element region; a wiring layer formed by stacking, on the semiconductor element layer, wiring for establishing connection with the semiconductor element and a wiring insulating film extending to the surface acoustic wave element region and for insulating the wiring; and a piezoelectric thin film formed above the wiring insulating film, the piezoelectric thin film extending into the surface acoustic wave region and the IC region; and in the surface acoustic wave element region, a surface acoustic wave element formed on the piezoelectric thin film and equipped with an IDT electrode provided with a plurality of electrode fingers; and at least one layer of layer thickness adjusting films having linear shapes and arranged in parallel to and with the same pitch as the electrode fingers of the IDT electrode, and formed above one of the semiconductor substrate, the element insulating film, and the wiring insulating film, and below an area in which the surface acoustic wave element is formed.