Piezoelectric vibrating reed, piezoelectric vibrating reed manufacturing method, piezoelectric vibrator, oscillator, electronic device and radio timepiece

Abstract

An electrode forming step of forming a pair of electrodes by patterning an electrode film on an outer surface of a piezoelectric plate includes: an electrode film forming step of forming the electrode film; a photoresist film forming step of forming a photoresist film on the electrode film; a first exposure step of exposing the photoresist film through a mask; and a second exposure step of further exposing the photoresist film through a correction mask on which a second opening is disposed at a position overlapping with a part of the first opening. An opening width of the second opening corresponding to a clearance between the pair of electrodes is equal to or less than an opening width of the first opening corresponding to the clearance.

1 . A method of manufacturing piezoelectric vibrating reeds comprising:
 forming an electrode film on a piezoelectric reed;   forming a photoresist film on the electrode film formed on the piezoelectric reed;   photographically removing part of the photoresist film with a first mask having a first strip pattern which defines a first in-between distance substantially equal to a distance between adjacent electrodes to be formed from the electrode film;   photographically exposing the partially removed photoresist film with a second mask having a second strip pattern co-extensive with the first strip pattern exposed by the first mask on the photoresist film, wherein the second strip pattern is narrower than the first strip pattern; and   photographically removing part of the electrode film formed on the piezoelectric reed according to a pattern of the photoresist film removed by the first and second masks.   
     
     
         2 . The method according to  claim 1 , wherein the first and second masks have second and third strip patterns, respectively, which are coextensive with each other and substantially equal in width. 
     
     
         3 . The method according to  claim 2 , wherein the piezoelectric reed is a of a tuning-fork type which has a base and a pair of arms extending from the base, and the second the third strip patterns lie on the base between the arms near proximal ends of the arms. 
     
     
         4 . The method according to  claim 1 , wherein the piezoelectric reed is an AT-cut piezoelectric reed.