Process for Adapting Resonance Frequency of a BAW Resonator

摘要

A method of manufacturing a filter circuit including series and parallel coupled BAW resonators is given which compensates for frequency tolerances of the resonators which are due to the manufacturing process. The new method includes measuring a resonance frequency of at least one type of the BAW resonators produced on a wafer and defining a deviation from a desired frequency. A trimming layer is then deposited onto the entire wafer. At last, a thickness portion of the trimming layer is selectively removed, the portion being dependent on a location on the wafer and on the calculated deviation of the resonance frequency at this location.