Patent ID: 8677582

Claim:
A method for fabricating an acoustic wave device, the method comprising the steps of: forming an insulating material layer on a piezoelectric substrate; forming a patterned photoresist on the insulating material layer, patterning the insulating material layer, and forming a piezoelectric-substrate exposed depression corresponding to a region where an interdigital transducer electrode is to be formed on a first insulator layer composed of the insulating material layer; depositing a metallic material on the piezoelectric substrate to form the interdigital transducer electrode in the piezoelectric-substrate exposed depression such that the overall interdigital transducer electrode is thinner than the first insulator layer and coating the photoresist with the metallic material; removing the photoresist and the metallic material on the photoresist; and depositing a second insulator layer so as to cover the interdigital transducer electrode and the first insulator layer; wherein the second insulator layer includes an upper surface and a lower surface opposed to the upper surface; the upper surface of the second insulator layer includes a first surface region under which the interdigital transducer electrode is located and a second surface region under which the interdigital transducer electrode is not located; and the step of depositing the second insulator layer is performed such that a height of at least a portion of the second surface region of the second insulator layer measured from the piezoelectric substrate is greater than a height of at least a portion of the first surface region of the second insulator layer measured from the piezoelectric substrate.