Patent ID: 9209591
Filing Date: 2015-12-08
Classification: H01L,H01S

Abstract:
1. A laser processing method of applying a pulsed laser beam to a single crystal substrate to thereby process the single crystal substrate, the laser processing method comprising: a numerical aperture setting step of setting a numerical aperture (NA) of a focusing lens for focusing the pulsed laser beam so that a value obtained by dividing the numerical aperture (NA) of the focusing lens by a refractive index (N) of the single crystal substrate falls within the range of 0.05 to 0.2; a positioning step of relatively positioning the focusing lens and the single crystal substrate in a direction along an optical axis of the focusing lens so that a focal point of the pulsed laser beam is set at a desired position in a direction along the thickness of the single crystal substrate; and a shield tunnel forming step of applying the pulsed laser beam to the single crystal substrate so as to focus the pulsed laser beam at the focal point set in the single crystal substrate by the positioning step, thereby forming a shield tunnel extending between the focal point and a beam incident surface to which the pulsed laser beam is applied, the shield tunnel being composed of a fine hole and an amorphous region formed around the fine hole for shielding the fine hole.