A polishing method for polishing a wafer by use of a polishing unit having a spindle with a polishing tool, the polishing tool having a disk-shaped base and an annular polishing layer that is fixed to one surface of the base and that includes an opening being located at a central portion in a diameter direction of the base and having a predetermined diameter, a maximum width of an effective polishing region of the polishing layer in a radial direction of the base being smaller than the radius of the wafer and the radius of the wafer being smaller than the diameter of the opening, the method includes polishing the wafer in such a manner that a part of a peripheral edge of the wafer protrudes from a periphery of the polishing layer and that the center of the wafer is located in the opening section of the polishing layer.

The present invention relates to a chamfered silicon carbide substrate which is essentially monocrystalline, and to a corresponding method of chamfering a silicon carbide substrate. A silicon carbide substrate according to the invention comprises a main surface (102), wherein an orientation of said main surface (102) is such that a normal vector ({right arrow over (O)}) of the main surface (102) includes a tilt angle with a normal vector ({right arrow over (N)}) of a basal lattice plane (106) of the substrate, and a chamfered peripheral region (110), wherein a surface of the chamfered peripheral region includes a bevel angle with said main surface, wherein said bevel angle is chosen so that, in more than 75% of the peripheral region, normal vectors ({right arrow over (F)}_i) of the chamfered peripheral region (110) differ from the normal vector of the basal lattice plane by less than a difference between the normal vector of the main surface and the normal vector of the basal lattice plane of the substrate.

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.

A method for preparing a SiC ingot includes: disposing a raw material and a SiC seed crystal facing each other in a reactor having an internal space; subliming the raw material by controlling a temperature, a pressure, and an atmosphere of the internal space; growing the SiC ingot on the seed crystal; and collecting the SiC ingot after cooling the reactor. The wafer prepared from the ingot, which is prepared from the method, generates cracks when an impact is applied to a surface of the wafer, the impact is applied by an external impact source having mechanical energy, and a minimum value of the mechanical energy is 0.194 J to 0.475 J per unit area (cm.sup.2).

A method of manufacturing a SiC substrate includes grinding a sliced SiC substrate on a side of its front surface on which a Si-face is exposed, grinding the sliced SiC substrate on a side of its back surface on which a C-face is exposed, such that the back surface has an arithmetic mean height Sa of 1 nm or less, and then polishing the sliced SiC substrate on the side of only the front surface and not on the side of the back surface. In a case where the side of the back surface is ground as described above, the SiC substrate can be prevented from being warped even if the side of the back surface is not polished. This can shorten the manufacturing lead time for the SiC substrate used for the manufacture of power devices or the like and can also reduce the manufacturing cost.

A vacuum chuck includes: a vacuum chuck stage having a circular vacuum surface; a vacuum protection pad provided to the vacuum surface; an annular or arc-shaped concave portion dividing the vacuum surface into a central region located closer to a center of the vacuum surface and an outer circumferential region located on an outer circumferential side; and radially-extending concave portions formed in the central region. The vacuum protection pad has through holes in communication with the radially-extending concave portions, and the vacuum protection pad is bonded to the vacuum surface at the central region excluding the radially-extending concave portions.

A substrate processing apparatus which causes a processing tape to abut against a processing object, including: a tape supply reel configured to supply the processing tape; a tape recovery reel configured to recover the processing tape; a recovery motor configured to apply a torque to the tape recovery reel; a tape feed motor configured to feed the processing tape between the tape supply reel and the tape recovery reel; and a control unit configured to control the tape feed motor, wherein the control unit controls the torque of the recovery motor depending on a change in an outer diameter of a roll of the processing tape wound by the tape recovery reel such that tension applied to the processing tape is constant, using a feed length of the tape fed by the tape feed motor and a thickness of the processing tape.

Method for processing a semiconductor-wafer having a front surface, back surface, and chamfered-portion composed of a chamfered surface on the front surface side, a chamfered surface on the back surface side, and an end face at a peripheral end, including: mirror-polishing of each portion of the chamfered surface on the front surface side, the chamfered surface on the back surface side, the end face, and an outermost peripheral-portion on the front or back surface adjacent to the chamfered surface; wherein the end face mirror-polishing and mirror-polishing of the outermost peripheral-portion on the front or back surface are performed in one step, after step of mirror-polishing the chamfered surface on the front surface side and step of mirror-polishing the chamfered surface on the back surface side; roll-off amount of the outermost peripheral-portion on the front or back surface is adjusted by one step-performed mirror-polishing of the end face and outermost peripheral-portion.

A polishing apparatus which can maintain a polishing load within an appropriate range is disclosed. The polishing apparatus includes: a pressing member for pressing a polishing tool against the substrate; an actuator configured to control a pressing force of the pressing member; a positioning member which is movable together with the pressing member; a stopper arranged to restrict movement of the pressing member and the positioning member; a stopper moving mechanism configured to move the stopper in a predetermined direction; a polishing-load detector configured to obtain a load feedback value which varies according to a polishing load applied to the pressing member; and a stopper-speed determining device configured to determine a movement speed of the stopper which can allow the load feedback value to fall within a set range.

A substrate processing apparatus which reliably prevents a cleaning liquid containing foreign particles from falling from a polishing head onto a substrate is disclosed. The substrate processing apparatus includes a rotating and holding mechanism, a polishing head, and a head cleaning device configured to supply the cleaning liquid to the polishing head to clean the polishing head during polishing and/or after polishing of the substrate.