Method for manufacturing piezoelectric vibration element and method for manufacturing piezoelectric vibrator

A method for manufacturing a piezoelectric vibration element, the method comprising:

• preparing a piezoelectric substrate having a first main surface and a second main surface opposing the first main surface;
• providing a first electrode layer on the first main surface of the piezoelectric substrate;
• arranging a mask on a side of the first main surface of the piezoelectric substrate, wherein the mask includes a center region and a peripheral region located along a periphery of the center region;
• and
• irradiating a radiation beam through the mask toward the first main surface of the piezoelectric substrate such that a larger amount of the radiation beam passes through the peripheral region than the center region of the mask so as to remove a part of the first electrode layer to form a first excitation electrode that decreases in thickness from the center region to the peripheral region of the mask on the first main surface of the piezoelectric substrate.