A wafer processing method includes a first grinding step and a second grinding step. In the first grinding step, first grinding abrasives are moved in a processing feed direction that is a direction orthogonal to a holding surface of a chuck table of grinding apparatus and a wafer is ground to form a first circular recess in the back surface of the wafer. In the second grinding step, second grinding abrasives formed of finer abrasive grains than the first grinding abrasives are moved down in an oblique direction from the center side of the wafer toward the periphery of the wafer and the first circular recess is ground.

We describe an apparatus for controlling a thickness of a workpiece element, the apparatus comprising: a lapping machine having a lapping plate; and a holder to hold a workpiece element; wherein said holder comprises: a workpiece element mount to mount a workpiece element to be lapped such that a surface of said workpiece element lies substantially flush with a lower face of said holder; an adjustable actuator to controllably move said surface of said workpiece element so that it remains substantially flush or projects beyond said lower face of said holder during lapping; means for urging said holder towards said lapping plate; and a sensor for sensing a displacement of the workpiece element towards said lapping plate.

A spindle unit mounted to a processing unit has a collar section extending from an outside surface of the spindle unit in a horizontal direction. The processing unit includes a bottom plate having a through-hole through which a lower portion of the spindle unit penetrates, a holder including a side plate that surrounds the spindle unit with the collar section supported by the bottom plate and that is connected to the bottom plate, and an inclination adjusting mechanism that acts on the collar section to adjust the inclination of the spindle unit. The inclination adjusting mechanism includes a spring interposed between a lower surface of the collar section and an upper surface of the bottom plate and an adjusting section that acts to compress the spring and adjusts the inclination of the spindle unit by a compression amount of the spring.

A support base supports a plate-shaped workpiece. The support base includes a flat plate-shaped box member having a support face for supporting a workpiece and a placement face that is a face on the opposite side to the support face and is placed on a holding face of a chuck table, a temperature measurement unit accommodated in the box member, and a battery accommodated in the box member and serving as a power supply for the temperature measurement unit. The temperature measurement unit includes a temperature measuring instrument that measures a temperature at the support face, and a recording unit that records the temperature measured by the temperature measuring instrument.

A RAMO.sub.4 substrate is formed from single crystal represented by a formula of RAMO.sub.4 (in the formula, R indicates one or a plurality of trivalent elements selected from a group consisting of Sc, In, Y, and a lanthanoid element, A indicates one or a plurality of trivalent elements selected from a group consisting of Fe(III), Ga, and Al, and M indicates one or a plurality of bivalent elements selected form a group consisting of Hg, Mn, Fe(II), Co, Cu, Zn, and Cd). An epitaxially-grown surface is provided on at least one surface of the RAMO.sub.4 substrate. The epitaxially-grown surface includes a plurality of cleavage surfaces which are regularly distributed, and are separated from each other.

An Si substrate manufacturing method includes a separation band forming step of forming a separation band through positioning a focal point of a laser beam with a wavelength having transmissibility with respect to Si to a depth, equivalent to a thickness of an Si substrate to be manufactured, from a flat surface of an Si ingot and irradiating the Si ingot with the laser beam while relatively moving the focal point and the Si ingot in a direction <110> parallel to a cross line at which a crystal plane {100} and a crystal plane {111} intersect or a direction [110] orthogonal to the cross line, and an indexing feed step of executing indexing feed of the focal point and the Si ingot relatively in a direction orthogonal to a direction in which the separation band is formed.

Disclosed is a wafer polishing apparatus including a base, a lower surface plate disposed on the upper surface of the base, an upper surface plate disposed on the lower surface plate and a first shape adjustment unit configured to deform the shape of the lower surface of the upper surface plate so that the lower surface of the upper surface plate has one of a concave shape, a flat shape and a convex shape in a first direction, and the first direction is a direction from the lower surface plate to the upper surface plate.

Provided is a method for filtering an additive-containing liquid that can achieve a polishing composition exhibiting excellent defect reducing capability while maintaining a practical filter life. The method for filtering a polishing additive-containing liquid provided by the present invention includes the step of: filtering the polishing additive-containing liquid with a filter that satisfies the following conditions (1) and (2). (1) The average pore diameter P measured by a palm porometer is 0.15 μm or less. (2) The pore diameter gradient (S.sub.in/S.sub.out), which is the ratio of the inlet-side average pore diameter (SO to the outlet-side average pore diameter (S.sub.out), both diameters being measured through observation with an SEM, is 3 or less.

A dressing tool, to be used in dressing a plurality of grindstones arrayed in an annular pattern on one surface side of a grinding wheel, includes a dressing section for dressing the plurality of grindstones, a support plate that is located on a side opposite to a front surface side of the dressing section making contact with the plurality of grindstones and that supports a back surface side of the dressing section, and an RFID tag from and in which information concerning the dressing tool is read and written. One of or both the support plate and the dressing section are provided with a recess, and the RFID tag is disposed in the recess and is fixed by a non-conductive material provided in the recess.

A processing method for a wafer having a chamfered portion at a peripheral edge includes a holding step of holding the wafer by a holding table, and a chamfer removing step of rotating the holding table while causing a first cutting blade to cut into the peripheral edge of the wafer while supplying a cutting liquid from a first cutting liquid supply nozzle to cut the peripheral edge of the wafer. In the chamfer removing step, a second cutting unit is positioned at a position adjacent to the first cutting unit at such a height that a second cutting blade does not make contact with the wafer and on the side of the center of the wafer as compared to the first cutting unit, and the cutting liquid is supplied from a second cutting liquid supply nozzle.