A method of processing a workpiece includes a holding step, a height position detecting step, a modified layer forming step, and a dividing step. The height position detecting step is a step of, after the holding step, applying a measuring laser beam emitted from a height position detecting unit to the workpiece while moving a chuck table that holds the workpiece thereon and the height position detecting unit relatively to each other to detect a height position of the workpiece using a reflected beam from a reverse side of the workpiece. In the height position detecting step, the measuring laser beam is applied clear of areas of the workpiece where columnar conductive electrodes are embedded in streets.

Systems and methods for dicing a sample by a Bessel beam matrix are disclosed. The method for dicing a sample by a Bessel beam matrix may comprise generating a Bessel beam matrix including multiple Bessel beams arranged in a matrix form, according to a predetermined dicing layout of the sample; controlling a focus position of each Bessel beam in the generated Bessel beam matrix; and focusing simultaneously the Bessel beams of the Bessel beam matrix at the respective controlled focus positions within the sample for dicing.

A method for controlled machining of a workpiece includes focusing a laser light beam on a target point of the workpiece to generate a laser focus point. An optical distance measuring device gathers measuring data to determine a distance between the target point and a laser target optics. The workpiece is positioned in relation to the laser focus point based on the distance measuring data gathered. The distance measuring device is a confocal optical distance measuring device having a measuring light source for generating a measuring light and having a variable-focal-length measuring lens system. The focal length of the variable-focal-length measuring lens system is varied over time to gather distance measuring data at different focal length values of the variable-focal-length measuring lens system. A device for controlled machining includes a laser light source, a laser target optics, a distance measuring device, a positioning device, and an evaluation and control unit.

Methods of dicing semiconductor wafers are described. In an example, a method of dicing a wafer having a plurality of integrated circuits thereon involves dicing the wafer into a plurality of singulated dies disposed above a dicing tape. The method also involves forming a material layer over and between the plurality of singulated dies above the dicing tape. The method also includes expanding the dicing tape, wherein a plurality of particles is collected on the material layer during the expanding.

A method of removing material from an opposite side of workpiece includes directing a laser beam at a first side of the workpiece to remove the material from an opposite second side of the workpiece.

A mask assembly, and an apparatus including the same are provided. The mask assembly includes a mask sheet. The mask sheet includes a pattern portion having openings, and a welding portion connected to the pattern portion. The welding portion has a grain size different from a grain size of the pattern portion.

Methods of dicing semiconductor wafers are described. In an example, a method of dicing a semiconductor wafer having integrated circuits thereon involves forming a mask above the semiconductor wafer, the mask composed of a layer covering and protecting the integrated circuits. The mask is then patterned with a multiple pass laser scribing process to provide a patterned mask with gaps exposing regions of the semiconductor wafer between the integrated circuits, the multiple pass laser scribing process including a first pass along a first edge scribing path, a second pass along a center scribing path, a third pass along a second edge scribing path, a fourth pass along the second edge scribing path, a fifth pass along the center scribing path, and a sixth pass along the first edge scribing path. The semiconductor wafer is then plasma etched through the gaps in the patterned mask to singulate the integrated circuits.

A method of processing silicon carbide containing crystalline substrate is provided. The method includes pyrolyzing a surface of the silicon carbide containing crystalline substrate to produce a silicon and carbon containing debris layer over the silicon carbide containing crystalline substrate, and removing the silicon and carbon containing debris layer, wherein the pyrolyzing and the removing is repeated at least once.

A process for the production of laminar electric resistances having plan geometry according to a predetermined pattern. The laminar electric resistances are formed by a metallic foil, a rigid first template, a trace and at least one sheet of insulating material. The trace is shaped to substantially trace the plan geometry of the predetermined pattern forming a path. The first template includes a fixing means adapted to fix the metallic foil. The trace has a height from the base between 10 and 50 mm. The process includes the steps of: fixing the metallic foil onto the first template by means of fixing means; cutting, according to a predetermined pattern, the metallic foil with a laser to obtain a cut foil; adhering a first sheet of insulating material to a surface of the cut foil which is distal from the first template; and detaching the cut foil from the first template.

The present invention provides an optical mask plate and a laser lift-off device. The optical mask plate comprises at least one totally-transmissive region and a blocking region surrounding the totally-transmissive region. The totally-transmissive region allows lasers having a predetermined wavelength to completely pass therethrough, while the blocking region does not allow the lasers having the predetermined wavelength to pass therethrough. The laser lift-off device comprises the optical mask plate. During the whole process of scanning a rigid substrate with the laser beam, as a laser emitter for emitting the laser beam can be in an on state all the time, the energy of the laser beam is nearly uniform in the process of scanning the rigid substrate with the laser beam, and in this way, edge portions of a flexible device can be prevented from being burned by the laser beam.