Patent ID: 6462460
Filing Date: 2002-10-08
Classification: H03H

Abstract:
A method of tuning a bulk acoustic wave device during a fabrication process thereof, wherein the bulk acoustic wave device comprises a plurality of acoustic wave generating and controlling layers formed on a substrate, and the acoustic wave generating and controlling layers include a bottom electrode layer, a piezoelectric layer, a top electrode layer and a passivation layer, one of which can be a surface layer of the bulk acoustic wave device during the fabrication process, and wherein the surface layer has a layer thickness with a non-uniformity profile defining a plurality of locations at which the thickness non-uniformity of the surface layer requires thickness adjustment, and wherein the bulk acoustic wave device has an operating frequency which varies partly with the layer thickness, and the operating frequency can be adjusted by adjusting the layer thickness, said method comprising the steps of:providing an etching medium over the surface layer at one section thereof for locally adjusting, according to the thickness non-uniformity profile, the thickness of at least one of said plurality of locations; relocating the etching medium, relative to the device, to another section of the surface layer for locally adjusting, according to the thickness non-uniformity profile, the thickness of at least another of said plurality of locations; and repeating the relocating until the thickness of substantially all of said plurality of locations according to the thickness non-uniformity profile has been adjusted.