Patent ID: 11962282
Assignee: TAIYO YUDEN CO., LTD.
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 15:
16. An acoustic wave device comprising:
a support substrate;
a piezoelectric layer provided over the support substrate;
at least one pair of comb-shaped electrodes disposed on the piezoelectric layer, each of the at least one pair of comb-shaped electrodes including electrode fingers;
a temperature compensation film interposed between the support substrate and the piezoelectric layer, the temperature compensation film having a temperature coefficient of elastic constant opposite in sign to a temperature coefficient of elastic constant of the piezoelectric layer; and
an insulating layer interposed between the support substrate and the temperature compensation film, a first surface of the insulating layer having a plurality of first protruding portions and/or a plurality of first recessed portions, a second surface of the insulating layer having a plurality of second protruding portions and/or a plurality of second recessed portions, the first surface being closer to the support substrate, the second surface being closer to the temperature compensation film,
wherein an arithmetic average roughness Ra of the second surface is 1 nm or less.