A method includes applying laser pulses along a direction to a side of a wafer to create first and second stealth damage regions at respective first and second depths in the wafer and to create cracks that extend in the wafer from the respective stealth damage regions and that are spaced apart from one another along the direction, applying a compressive and retractive cyclical force to the wafer along the third direction to propagate and join the cracks from the respective stealth damage regions together, and expanding the wafer to separate individual dies from the wafer.

The invention provides a method for laser modification of a sample to form a modified region at a target location within the sample. The method comprises positioning a sample in a laser system for modification by a laser; measuring tilt of a surface of the sample through which the laser focusses; using at least the measured tilt to determine a correction to be applied to an active optical element of the laser system; applying the correction to the active optical element to modify wavefront properties of the laser to counteract an effect of coma on laser focus; and laser modifying the sample at the target location using the laser with the corrected wavefront properties to produce the modified region.

A wafer has a device area on one side with a plurality of devices partitioned by a plurality of division lines. Either side of the wafer is attached to an adhesive tape supported by a first annular frame. A modified region is formed in the wafer along the division lines by a laser. The wafer is placed on a support member whose outer diameter is smaller than an inner diameter of the first annular frame. After applying the laser beam, the adhesive tape is expanded thereby dividing the wafer along the division lines. A second annular frame is attached to a portion of the expanded adhesive tape. An inner diameter of the second annular frame is smaller than the outer diameter of the support member and smaller than the inner diameter of the first annular frame.

A method of manufacturing ceramic chips according to one aspect of the present disclosure includes: (A) forming a plurality of dicing trenches on a ceramic wafer; (B) removing a surface in which the dicing trenches are formed by as much as a predetermined thickness to eliminate a rough surface, which is formed on an outer side of each of the dicing trenches when the dicing trenches are formed; and (C) removing a surface opposite to the surface in which the dicing trenches are formed by as much as a predetermined thickness so that the wafer is individualized into a plurality of ceramic chips.

Disclosed herein is a wafer producing method for producing an SiC wafer from a single crystal SiC ingot. The wafer producing method includes a separation surface forming step of forming a separation surface composed of modified layers, cracks, and connection layers inside the ingot and a wafer separating step of separating a part of the ingot along the separation surface as an interface to thereby produce the wafer. The separation surface forming step includes a modified layer forming step of forming the modified layers and the cracks extending from the modified layers along a c-plane, and a connection layer forming step of forming the connection layers each connecting the cracks formed adjacent to each other in the thickness direction of the ingot.

A laser beam machining method and a laser beam machining device capable of cutting a work without producing a fusing and a cracking out of a predetermined cutting line on the surface of the work, wherein a pulse laser beam is radiated on the predetermined cut line on the surface of the work under the conditions causing a multiple photon absorption and with a condensed point aligned to the inside of the work, and a modified area is formed inside the work along the predetermined determined cut line by moving the condensed point along the predetermined cut line, whereby the work can be cut with a rather small force by cracking the work along the predetermined cut line starting from the modified area and, because the pulse laser beam radiated is not almost absorbed onto the surface of the work, the surface is not fused even if the modified area is formed.

A substrate dividing method which can thin and divide a substrate while preventing chipping and cracking from occurring. This substrate dividing method comprises the steps of irradiating a semiconductor substrate 1 having a front face 3 formed with functional devices 19 with laser light while positioning a light-converging point within the substrate, so as to form a modified region including a molten processed region due to multiphoton absorption within the semiconductor substrate 1, and causing the modified region including the molten processed region to form a starting point region for cutting; and grinding a rear face 21 of the semiconductor substrate 1 after the step of forming the starting point region for cutting such that the semiconductor substrate 1 attains a predetermined thickness.

A strengthened glass sheet is separated into undamaged sheet segments by mechanically scribing one or more vent lines of controlled depth into the sheet surface, the depths of the scribed lines being insufficient to effect sheet separation, and then applying a uniform bending moment across the vent lines to effect separation into multiple sheet segments, the vent lines being scribed from crack initiation sites comprising surface indentations formed proximate to the edges of the glass sheet.

There is provided a laser processing method for cutting a semiconductor object along a virtual plane facing a surface of the semiconductor object in the semiconductor object. The laser processing method includes a first step of forming a plurality of first modified spots along the virtual plane to obtain first formation density, by causing laser light to enter into the semiconductor object from the surface, and a second step of forming a plurality of second modified spots along the virtual plane so as to obtain second formation density higher than the first formation density, by causing laser light to enter into the semiconductor object from the surface after the first step.

A wafer producing method for producing a hexagonal single crystal wafer from a hexagonal single crystal ingot includes a separation start point forming step of setting the focal point of a laser beam inside the ingot at a predetermined depth from the upper surface of the ingot, which depth corresponds to the thickness of the wafer to be produced, and next applying the laser beam to the upper surface of the ingot while relatively moving the focal point and the ingot to thereby form a modified layer parallel to the upper surface of the ingot and cracks extending from the modified layer, thus forming a separation start point. In the separation start point forming step, the laser beam is applied to the ingot plural times with the focal point of the laser beam set at the modified layer previously formed, thereby separating the cracks from the modified layer.