A cutting unit includes a spindle housing, a spindle, a mounter fixed to the front end portion of the spindle for supporting a cutting blade, and a fixing flange for fixing the cutting blade to the mounter. The mounter includes a boss portion for axially slidably supporting the fixing flange, the boss portion being fitted to an engaging hole formed in a central portion of the fixing flange, a flange portion projecting radially outward from the outer circumference of the boss portion, the flange portion having a supporting surface for supporting the cutting blade on the front side opposed to the fixing flange, and a cylindrical portion formed on the rear side of the flange portion. The flange portion has a suction hole opening. The cylindrical portion has a communication passage communicating with the suction hole. The communication passage is connected through a rotary joint to a suction unit.

An ultrasonic resonator support structure 10 including a holder 17 supports an ultrasonic resonator 16 at both sides such that the ultrasonic resonator 16 is rotatable to the holder 17. The ultrasonic resonator 16 includes an ultrasonic horn 13 with a machining tool 12 attached, and a first booster 14 and a second booster 15 coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn 13. The holder 17 has a rolling bearing mechanism 18 that rotatably supports the first booster 14 side of the ultrasonic resonator 16 and a gas bearing mechanism 19 that rotatably supports the second booster 15 side of the ultrasonic resonator 16.

An ultrasonic resonator support structure 10 including a holder 17 supports an ultrasonic resonator 16 at both sides such that the ultrasonic resonator 16 is rotatable to the holder 17. The ultrasonic resonator 16 includes an ultrasonic horn 13 with a machining tool 12 attached, and a first booster 14 and a second booster 15 coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn 13. The holder 17 has a rolling bearing mechanism 18 that rotatably supports the first booster 14 side of the ultrasonic resonator 16 and a gas bearing mechanism 19 that rotatably supports the second booster 15 side of the ultrasonic resonator 16.

A cutting apparatus includes a width measuring unit for measuring the width of a grooving groove formed in a wafer by laser grooving and the width of a cut groove formed by a cutting blade. The width measuring unit includes an imaging camera for imaging the grooving groove and the cut groove, and an illuminating unit for illuminating an area to be imaged by the imaging camera with light supplied in a predetermined light quantity. Therefore, when first light is radiated from the illuminating unit, a first image in which the grooving groove is sharply imaged can be imaged by the imaging camera, whereas when second light is radiated from the illuminating unit, a second image in which the cut groove is clearly imaged can be imaged by the imaging camera. Consequently, the grooving groove and the cut groove can be easily distinguished from each other.

A method of processing a wafer having a first surface and a second surface opposite the first surface is provided. The method includes the steps of: holding the second surface of the wafer such that the first surface thereof is exposed; processing an exposed first surface side of an outer circumferential edge portion of the wafer with a processing tool including a grinding stone made of abrasive grains bound together by a bonding material, thereby forming on the outer circumferential edge portion a slanted surface that is inclined to the first surface so as to be progressively closer to the second surface in a direction from a central area of the wafer toward an outer circumferential edge thereof; and coating the first surface of the wafer with a liquid material according to a spin coating process, thereby forming a resist film on the first surface of the wafer.

In an outer blade cutting wheel comprising an annular thin disc base of cemented carbide having an outer diameter of 80-200 mm, an inner diameter of 30-80 mm, and a thickness of 0.1-1.0 mm, and a blade section disposed on an outer periphery of the base, the blade section comprises diamond grains and/or CBN grains bound with a metal bond having a Young's modulus of 0.7-4.0×10.sup.11 Pa and has a thickness which is greater than the thickness of the base by at least 0.01 mm. The outer blade cutting wheel is capable of cutting a workpiece at a high accuracy and a reduced allowance, improves machining yields, and reduces machining costs.

An edge trimming method for cutting an outer peripheral portion of a workpiece having a chamfered part on the outer peripheral portion. The method includes a cut in step of relatively moving a rotating cutting blade and a chuck table to cause the blade to cut into the outer peripheral portion, a cutting step of, after the cut in step, rotating the chuck table and causing the outer peripheral portion to be cut, to form an annular step, and a moving step of, after the cutting step, moving the blade in a direction of its axis of rotation to form another annular step adjacent to the first-mentioned annular step. The cut in, cutting, and moving steps are repeated in this order, and a stepped oblique region is formed on the outer peripheral portion, with a thickness increasing from an outermost peripheral edge toward an inner side of the workpiece.

A transfer jig for use in transferring a new cutting blade as a replacement component to the processing unit, in a cutting apparatus including a chuck table holding a workpiece, a processing unit having a spindle and a cutting blade detachably mounted on the spindle, a cutting blade changing unit changing the cutting blade, and a transfer mechanism supplying the workpiece to the processing unit. The transfer jig has a plurality of receiving portions each adapted to receive the new cutting blade and the cutting blade changed by the cutting blade changing unit. The transfer jig is adapted to be transferred by the transfer mechanism transferring the workpiece.

An ultrasonic resonator support structure including a holder supports an ultrasonic resonator at both sides such that the ultrasonic resonator is rotatable to the holder. The ultrasonic resonator includes an ultrasonic horn with a machining tool attached, and a first booster and a second booster coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn. The holder has a rolling bearing mechanism that rotatably supports the first booster side of the ultrasonic resonator and a gas bearing mechanism that rotatably supports the second booster side of the ultrasonic resonator.

An ultrasonic resonator support structure including a holder supports an ultrasonic resonator at both sides such that the ultrasonic resonator is rotatable to the holder. The ultrasonic resonator includes an ultrasonic horn with a machining tool attached, and a first booster and a second booster coaxially fixed one by one to both ends in the axial directions of the ultrasonic horn. The holder has a rolling bearing mechanism that rotatably supports the first booster side of the ultrasonic resonator and a gas bearing mechanism that rotatably supports the second booster side of the ultrasonic resonator.