PROCESSING METHOD OF CRYSTAL BLANK AND CRYSTAL RESONANCE CHIP

PROBLEM TO BE SOLVED: To provide a processing method capable of processing the cross section of a crystal blank to be tapered or convex by comparatively easy control, and to provide a crystal resonance chip with an excellent resonance characteristic. SOLUTION: Photoresists R1 to R5 with different sensitivity are recoated and stacked on a crystal element chip 1a in a way that sensitivity becomes higher from the surface of the crystal element chip 1a toward an upper layer. The crystal element chip 1a is irradiated with exposure light via a photomask 8 for exposure, and thereafter the photoresists R1 to R5 are developed. Since the photoresists R1 to R5 contain many unexposed parts toward the lower layer, a photoresist pattern after the development forms a cross-sectional tapered shape that spreads outwardly toward the surface of the crystal element chip 1a. Then the application of dry etching to a crystal wafer 1 by an RIE (reactive ion etching) method to form nearly a cross-sectional tapered shape on the end face of the crystal element chip 1a. COPYRIGHT: (C)2007,JPO&INPIT