AT-CUT CRYSTAL RESONATOR ELEMENT, AT-CUT CRYSTAL RESONATOR, AND AT-CUT CRYSTAL OSCILLATOR

摘要

PROBLEM TO BE SOLVED: To prevent cracks in splitting a large-area piezoelectric substrate wafer by sufficiently ensuring the thickness of a circular part surrounding a recess when employing batch processing of the wafer to mass-produce an ultra-small piezoelectric substrate having a vibration part formed by forming the recess by etching on a piezoelectric substrate surface made of an anisotropic piezoelectric crystal material.;SOLUTION: The piezoelectric substrate 2 includes a thin vibrating part 4 and a thick circular part 5 integrally surrounding the outer circumferential edge of the vibrating part, thereby forming the recess 3 on at least one main surface. The piezoelectric substrate 2 is made of piezoelectric crystal having anisotropy. In the circular part, an inner wall 5a on one crystal axis direction has an inclination angle more gradual than the inner wall on the other crystal axis direction which is perpendicular thereto, and the outer dimension of the piezoelectric substrate is such that the substrate length in the one crystal axis direction is longer than the substrate length in the other crystal axis direction.;COPYRIGHT: (C)2011,JPO&INPIT