Reducing the microvoid (MV) density in AlN ameliorates numerous problems related to cracking during crystal growth, etch pit generation during the polishing, reduction of the optical transparency in an AlN wafer, and, possibly, growth pit formation during epitaxial growth of AlN and/or AlGaN. This facilitates practical crystal production strategies and the formation of large, bulk AlN crystals with low defect densities—e.g., a dislocation density below 10.sup.4 cm.sup.−2 and an inclusion density below 10.sup.4 cm.sup.−3 and/or a MV density below 10.sup.4 cm.sup.−3.

Reducing the microvoid (MV) density in AlN ameliorates numerous problems related to cracking during crystal growth, etch pit generation during the polishing, reduction of the optical transparency in an AlN wafer, and, possibly, growth pit formation during epitaxial growth of AlN and/or AlGaN. This facilitates practical crystal production strategies and the formation of large, bulk AlN crystals with low defect densities—e.g., a dislocation density below 10.sup.4 cm.sup.−2 and an inclusion density below 10.sup.4 cm.sup.−3 and/or a MV density below 10.sup.4 cm.sup.−3.

The invention relates to a method of producing a substrate. The method comprises providing a workpiece having a first surface and a second surface opposite the first surface, and providing a carrier having a first surface and a second surface opposite the first surface. The method further comprises attaching the carrier to the workpiece, wherein at least a peripheral portion of the first surface of the carrier is attached to the first surface of the workpiece, and forming a modified layer inside the workpiece. Moreover, the method comprises dividing the workpiece along the modified layer, thereby obtaining the substrate, wherein the substrate has the carrier attached thereto, and removing carrier material from the side of the second surface of the carrier in a central portion of the carrier so as to form a recess in the carrier. The invention further relates to a substrate producing system for performing this method.

A multi-line cutting method, a multi-line cutting apparatus and use thereof, a semiconductor material and a power device. The multi-line cutting method includes following steps: configuring a line spool for winding cutting lines to vibrate under the excitation action of ultrasonic waves; and vibrating the cutting lines to cut an object to be cut under the conveying action of the line spool. The vibration of the cutting line under the excitation action of the ultrasonic waves can increase the energy of the cutting lines, enhance the cutting capability of the cutting lines, reduce the abrasion of the cutting lines, and force abrasive materials to impact and grind said object at high frequency and speed, and the chip removal speed is high, so that the surface curvature, the surface warpage, and the total thickness deviation of a product obtained after cutting are all small, and the cutting quality is high.

A cutting apparatus includes a cutting unit cutting a workpiece held on a chuck table, a processing-feed unit moving the chuck table, a moving unit moving the cutting unit, and a delivery pad delivering the workpiece to be cut to the chuck table and delivering the workpiece that has been cut on the chuck table. The delivery pad is mountable on and detachable from the moving unit, holds the workpiece under suction while being mounted on the moving unit, and delivers the workpiece by being moved by the moving unit while holding the workpiece under suction.

A crystalline material processing method includes forming subsurface laser damage at a first average depth position to form cracks in the substrate interior propagating outward from at least one subsurface laser damage pattern, followed by imaging the substrate top surface, analyzing the image to identify a condition indicative of presence of uncracked regions within the substrate, and taking one or more actions responsive to the analyzing. One potential action includes changing an instruction set for producing subsequent laser damage formation (at second or subsequent average depth positions), without necessarily forming additional damage at the first depth position. Another potential action includes forming additional subsurface laser damage at the first depth position. The substrate surface is illuminated with a diffuse light source arranged perpendicular to a primary substrate flat and positioned to a first side of the substrate, and imaged with an imaging device positioned to an opposing second side of the substrate.

A die matrix expander includes a subring including ≥3 pieces, and a wafer frame supporting a dicing tape having an indentation for receiving pieces of the subring. The subring prior to expansion sits below a level of the wafer frame and has an outer diameter <an inner diameter of the wafer frame. A translation guide coupled to the subring driven by mechanical force applier moves the subring pieces in an angled path upwards and outwards for stretching the dicing tape including to a top most stretched position above the wafer frame that is over or outside the wafer frame. A cap placed on the pieces of the subring after being fully expanded over the dicing tape locks the dicing tape in the top most stretched position and secures the pieces of the expanded subring in place including when within the indentation during an additional expansion during a subsequent die pick operation.

A method of cleaving includes providing a substrate. Optionally, the substrate includes β-gallium oxide, hexagonal zinc sulfide, or magnesium selenide. The substrate includes at least one natural cleave plane and a crystallinity. The substrate is cleaved along a first natural cleave plane of the at least one natural cleave plane. The cleaving the substrate along the first natural cleave plane includes the following. A micro-crack is generated in the substrate while maintaining the crystallinity adjacent to the micro-crack by generating a plurality of phonons in the substrate, the micro-crack comprising a micro-crack direction along the first natural cleave plane. The micro-crack is propagated along the first natural cleave plane while maintaining the crystallinity adjacent to the micro-crack. Optionally, generating a micro-crack in the substrate by generating a plurality of phonons in the substrate includes generating the plurality of phonons by electron-hole recombination. Optionally, the electron-hole recombination includes non-radiative electron-hole recombination.

A processing method for a workpiece includes a cutting step of cutting the workpiece along streets by a cutting blade having a V-shaped tip end, to form V grooves of which shallower parts are wider than deeper parts, and a cleaning step of cleaning a back surface of the workpiece with cleaning water, after the cutting step is carried out.

A method of separating a wafer including rows of light emitting devices is described. Dicing streets are provided on the wafer such that a respective one of the dicing streets is provided between each of the rows of light emitting devices on the wafer. The wafer is broken along a first one of the dicing streets to separate a first portion of the wafer from a remaining portion of the wafer. The first portion of the wafer includes more than one of the rows of light emitting devices. The first portion of the wafer is broken along a second one of the dicing streets to separate a second portion of the wafer from the first portion of the wafer.