A method of manufacturing a surface acoustic wave device

A method of manufacturing a surface acoustic wave device, comprising the steps of: Preparing a piezoelectric substrate (10a); Forming a thin film electrode made of a metal film on the piezoelectric substrate (10a); Etching the thin film electrode for forming an interdigital transducer (IDT) (2); Trimming of the piezoelectric substrate (10a) and / or of the IDT (2), wherein said trimming the removal of a layer (2a) extending at least on a surface of IDT before the step of trimming (2) is formed, and adjusting the frequency of the surface acoustic wave device comprises; and Modifying the surface of the IDT (2) for stabilizing the surface of the IDT (2) by a heat treatment of the surface acoustic wave device, wherein changing the surface of the IDT (2) according to the frequency adjustment forming a stabilizing layer (2b; 2c) of the on the surface IDT (2), the fine-controls the frequency response of the surface acoustic wave device and stabilized, wherein a duration and a temperature of the heat treatment of the surface acoustic wave device depends on a difference between ...