Patent ID: 8291559
Filing Date: 2012-10-23
Classification: H03H,Y10T

Abstract:
1. A method of manufacturing a filter circuit comprising series and parallel coupled BAW resonators, the method comprising: depositing functional layers of a plurality of BAW resonators onto a substrate wafer, the functional layers comprising a bottom electrode, a piezoelectric layer, and a top electrode; structuring each of the functional layers to receive a plurality of circuits of BAW resonators, each circuit comprising series BAW resonators electrically coupled in series and parallel BAW resonators electrically coupled in parallel, wherein the coupling is done by the electrode layers; depositing a tuning layer of a first dielectric selectively onto the parallel BAW resonators on the wafer; measuring a resonance frequency of at least one type of the BAW resonators on the wafer; calculating a deviation of the measured resonance frequencies from a desired value; depositing a trimming layer onto the entire wafer; and selectively removing a thickness portion of the trimming layer, the portion being dependent on a location on the wafer and on the calculated deviation at this location.