Patent ID: 6441702
Filing Date: 2002-08-27
Classification: H03H,Y10T

Abstract:
A method of tuning a bulk acoustic wave device comprising a substrate and a plurality of acoustic wave generating and controlling layers formed on the substrate, wherein the device has a top surface layer made of a surface material and a thickness with a thickness non-uniformity profile across the top surface layer, and wherein the device has an operating frequency which varies partly with the thickness of the top surface layer, and the operating frequency can be adjusted by adjusting the thickness of the top surface layer, said method comprising the steps of:providing, on top of the top surface layer, a mask made of a mask material having a further non-uniformity profile partly based on the thickness non-uniformity profile of the top surface layer; providing an etching agent over the mask for removing the mask material from at least one mask area to expose a corresponding surface area of the top surface layer to the etching agent; and removing part of surface material from the top surface layer at the exposed surface area until a desired thickness of the top surface layer is reached, while simultaneously removing the mask material to modify the exposed surface area.