Patent ID: 7861387

Claim:
A method for manufacturing a piezoelectric resonator element from a substrate made of a piezoelectric material, the method comprising: forming a first dry etching mask on a first masking region of a first surface of the substrate in a first mask forming process; forming a plurality of openings in the first dry etching mask; performing a first dry etching process; removing a portion of the substrate within each of the plurality of openings during the first dry etching process and after the first mask forming process to form a plurality of flutes; removing a portion of the substrate in areas between the first dry etching mask during the first dry etching process and after the first dry etching mask forming process to form etching-processed portions that extend into the substrate to a greater extent than each of the plurality of flutes after the first mask forming process; maintaining a first un-etched portion of the substrate remaining from each of the removed portions of the substrate in the areas between the first dry etching mask after the first dry etching process; forming an affected layer corresponding to the openings of the first dry etching mask and substrate during the first dry etching process; removing the first dry etching mask in a mask removing process and after the first dry etching process; performing a wet etching process; removing the affected layer during the wet etching process and following the removal of the first dry etching mask; etching a bottom surface of each flute during the wet etching process such that the bottom surface of each flute includes a sloped surface; and removing the first un-etched portion of the substrate during the wet etching process and after the mask removing process to form the piezoelectric resonator element.