Patent ID: 7594307

Claim:
A method for manufacturing a piezoelectric resonator in which vibrating electrodes are formed on both surfaces of a piezoelectric substrate such that the vibrating electrodes oppose each other and piezoelectric vibration is trapped between the vibrating electrodes, the method comprising the steps of: forming a first electrode in an area including at least the vibrating electrode on each surface of the piezoelectric substrate so that the first electrode at least on one surface is formed partially on the surface of the piezoelectric substrate to trap the piezoelectric vibration; measuring a frequency of a resonator including the first electrode; determining a thickness of a metallic film required for a frequency adjustment based on the measured frequency; forming a second electrode made of the metallic film having the determined thickness in an area including at least the vibrating electrode on at least one surface of the piezoelectric substrate such that the second electrode is overlaid on the first electrode; and removing portions of the first electrode and the second electrode such that the vibrating electrodes on both the surfaces of the piezoelectric substrate oppose each other so that the entire vibrating electrode on the surface of the piezoelectric substrate on which the second electrode is formed becomes a laminated structure of the first electrode and the second electrode; wherein in the step of forming the first electrode, the first electrode is formed such that the resonator is arranged to vibrate in a vibration mode in the step of measuring the frequency of the resonator including the first electrode; and in the step of removing the portions of the first electrode and the second electrode, the portions are removed such that the resonator is arranged to vibrate in the same vibration mode in which the resonator is arranged to vibrate in the step of measuring the frequency of the resonator.