Process for adapting resonance frequency of a BAW resonator
First Claim
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.
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Abstract
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.
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Citations
14 Claims
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1. A method of manufacturing a filter circuit comprising series and parallel coupled BAW resonators, the method comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification