Methods of separating a glass web include exposing a separation path on the glass web to a laser beam that produces thermal stress along the separation path without damaging the glass web. The methods further include redirecting a portion of the laser beam to create a defect on the separation path while the separation path is under thermal stress produced during the exposing the separation path on the glass web to the laser beam, whereupon the glass web separates along the separation path in response to creating the defect. Apparatus are further provided for separating a glass web with at least one laser beam generator that produces a laser beam to heat a separation path and a mirror configured to reflect an end portion of the laser beam to create a defect at a location of the separation path on the glass web.

A silicon wafer forming method includes: a block ingot forming step of cutting a silicon ingot to form block ingots; a planarizing step of grinding an end face of the block ingot to planarize the end face; a separation layer forming step of applying a laser beam of such a wavelength as to be transmitted through silicon to the block ingot, with a focal point of the laser beam positioned in the inside of the block ingot at a depth from the end face of the block ingot corresponding to the thickness of the wafer to be formed, to form a separation layer; and a wafer forming step of separating the silicon wafer to be formed from the separation layer.

A silicon wafer forming method includes: a block ingot forming step of cutting a silicon ingot to form block ingots; a planarizing step of grinding an end face of the block ingot to planarize the end face; a separation layer forming step of applying a laser beam of such a wavelength as to be transmitted through silicon to the block ingot, with a focal point of the laser beam positioned in the inside of the block ingot at a depth from the end face of the block ingot corresponding to the thickness of the wafer to be formed, to form a separation layer; and a wafer forming step of separating the silicon wafer to be formed from the separation layer.

This laser processing apparatus is for forming modified regions in an object, which includes a sapphire substrate having a C-plane as a main surface, along cutting lines by focusing laser light on the object, and is provided with a laser light source, a spatial light modulator, and a focusing optical system. The spatial light modulator performs aberration correction by a first aberration correction amount smaller than an ideal aberration correction amount when the modified region is formed along a first cutting line along an a-axis direction of the sapphire substrate, and performs aberration correction by a second aberration correction amount smaller than the ideal aberration correction amount and different from the first aberration correction amount when the modified region is formed along a second cutting line along an in-axis direction of the sapphire substrate.

This laser processing apparatus is for forming modified regions in an object, which includes a sapphire substrate having a C-plane as a main surface, along cutting lines by focusing laser light on the object, and is provided with a laser light source, a spatial light modulator, and a focusing optical system. The spatial light modulator performs aberration correction by a first aberration correction amount smaller than an ideal aberration correction amount when the modified region is formed along a first cutting line along an a-axis direction of the sapphire substrate, and performs aberration correction by a second aberration correction amount smaller than the ideal aberration correction amount and different from the first aberration correction amount when the modified region is formed along a second cutting line along an in-axis direction of the sapphire substrate.

A method of separating a wafer into at least two thinner wafers includes a pressing member placing step of placing a pressing member that is transmissive of a wavelength of a laser beam on a first surface of the wafer such that the pressing member is pressed against the first surface of the wafer, a separation initiating point forming step of forming a separation initiating point in the wafer by applying the laser beam whose wavelength is transmittable through the wafer to the wafer while positioning a focused spot of the laser beam within the wafer and moving the focused spot and the wafer relatively to each other along a first direction, and an indexing feed step of moving the focused spot and the wafer relatively to each other along a second direction perpendicular to the first direction.

A method for microstructuring a plate-shaped glass substrate by laser radiation includes: introducing one-sided recesses into the glass substrate, in which a focus of the laser radiation forms a spatial beam along a beam axis and in which the laser radiation creates modifications in the glass substrate along the beam axis so that an action of an etching medium subsequently creates the recesses in the glass substrate through anisotropic removal of material in a respective region of the modifications. A chemical composition of the glass substrate is partially changed and thus at least one region of changed properties is created before the action of the etching medium.

The controller executes a first process of moving a support portion so that inside the peripheral edge of an object, a focusing position moves along the peripheral edge, thereby forming a first modified region, and following the first process, executes a second process of moving the support portion so that the focusing position moves, thereby forming a second modified region The measurement data acquiring portion, at execution of the first process, acquires measurement data associated with position information on a position of the object. The controller, at execution of the second process, causes the driving portion to shift a position of the condenser lens, the position being along the direction of an optical axis, to an initial position based on the measurement data acquired in the first process, before or when the focusing position moves from outside of the object to inside thereof.

The controller executes a first process of moving a support portion so that inside the peripheral edge of an object, a focusing position moves along the peripheral edge, thereby forming a first modified region, and following the first process, executes a second process of moving the support portion so that the focusing position moves, thereby forming a second modified region The measurement data acquiring portion, at execution of the first process, acquires measurement data associated with position information on a position of the object. The controller, at execution of the second process, causes the driving portion to shift a position of the condenser lens, the position being along the direction of an optical axis, to an initial position based on the measurement data acquired in the first process, before or when the focusing position moves from outside of the object to inside thereof.

A control unit performs first processing of irradiating an object with laser light while relatively moving a first converging point and a second converging point along a first line, in a state where a distance between the first converging point and a second converging point is set as a first distance, and performs second processing of irradiating the object with the laser light while relatively moving the first converging point and the second converging point along a second line, in a state where the distance between the first converging point and the second converging point is set to a second distance smaller than the first distance.