Patent ID: 7455786

Claim:
A method for manufacturing a piezoelectric oscillating circuit in thin film technology, wherein the piezoelectric oscillating circuit comprises a predetermined natural frequency, and wherein the piezoelectric oscillating circuit includes a piezoelectric layer having two opposing surfaces, a bottom electrode on one of the opposing surfaces and a top electrode on the other of the opposing surfaces, the method comprising: (a) depositing a first material which forms a first top electrode layer of the top electrode and which causes a first frequency change of the piezoelectric oscillating circuit depending on a thickness change of the first top electrode layer; (b) etching the first material for performing a first frequency correction such that a thinned first top electrode layer remains; (c) depositing a second material which forms a second top electrode layer on the thinned first top electrode layer and which causes a second frequency change of the piezoelectric oscillating circuit depending on a thickness change of the second top electrode layer, wherein the first frequency change is greater than the second frequency change; and (d) etching the second material for performing a second frequency correction such that a thinned second top electrode layer remains.