Patent ID: 8156621

Claim:
A process for making a tuning-fork type piezoelectric vibrator having at least two vibrating arms, comprising: forming a corrosion-resistant film on both major surfaces of a plate of piezoelectric single-crystal material having an anisotropic property; applying a layer of photoresist on the corrosion-resistant film on both major surfaces of the plate; performing a first exposure to form an outline pattern of a piezoelectric vibrator on the layer of photoresist on only one major surface of the plate; developing the exposed photoresist and removing regions of the corrosion-resistant film unprotected by the photoresist; applying a second layer of photo resist on the first and second major surfaces; performing a second exposure of respective second layers of photoresist on both major surfaces to form respective recessed regions on the vibrating arms; on only one major surface, performing a first etching of regions of the piezoelectric crystal material that are unprotected by the corrosion-resistant film; and performing a second etching of regions on both major surfaces of the piezoelectric material that are unprotected after removal of the corrosion-resistant film in the recessed regions.