PURPOSE: To rationalize a bevel processing process, to unify performance and to reduce a cost by providing a mask for the forming front and back plate face of the electrode of the surface and back face of a quartz piece and forming the thickness of the no-forming part/position of the electrode to be thin by wet etching. ;CONSTITUTION: The crystal piece 1 is wrapped to be in a thickness corresponding to a desired resonance frequency. A driving electrodes 2 are formed by mutually facing at the central part of the front and bace plate faces of the quartz piece 1 by vapour deposition, etc. In addition an electrode 3 for pulling out the driving electrode 2 is formed. Then, the quartz piece 1 is dipped into etching. By masking, the driving electrode 2 and the pulling-out electrode 3 are prevented from etching. Then, only a no-electrode part/position 4 on the surface of which quartz is exposed is etched to be thin in thickness to form a level difference between with the forming part/position of the electrode. By this constitution, a mechanically deteriorated layer is removed from the place surface of the quartz piece to obtain a satisfactory vibration characteristic and to reduce a processing time in addition.;COPYRIGHT: (C)1996,JPO
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