A polishing apparatus capable of forming a step-shaped recess having a right-angled cross section in an edge portion of a substrate, such as a wafer, is disclosed. The polishing apparatus includes: a substrate rotating device configured to rotate the substrate about a rotation axis; a first roller having a first circumferential surface configured to press a polishing tape against the edge portion of the substrate; and a second roller having a second circumferential surface in contact with the first circumferential surface. The second roller has a tape stopper surface that restricts movement of the polishing tape in a direction away from the rotation axis. The tape stopper surface is located radially outward of the first circumferential surface.

The present invention relates to a chemical mechanical polishing (CMP) apparatus for polishing a workpiece, such as a metal body, to a mirror finish. The chemical mechanical polishing apparatus includes: a polishing pad (2) having an annular polishing surface (2a) which has a curved vertical cross-section; a workpiece holder (11) for holding a workpiece (W) having a polygonal shape; a rotating device (15) configured to rotate the workpiece holder (11) about an axis of the workpiece (W); a pressing device (14) configured to press a periphery of the workpiece (W) against the annular polishing surface (2a); and an operation controller (25) configured to change a speed at which the rotating device (15) rotates the workpiece (W) according to a rotation angle of the workpiece (W). The pressing device (14) is disposed more inwardly than the workpiece holder (11) in a radial direction of the polishing table (3).

The present invention relates to a chemical mechanical polishing (CMP) apparatus for polishing a workpiece, such as a metal body, to a mirror finish. The chemical mechanical polishing apparatus includes: a polishing pad (2) having an annular polishing surface (2a) which has a curved vertical cross-section; a workpiece holder (11) for holding a workpiece (W) having a polygonal shape; a rotating device (15) configured to rotate the workpiece holder (11) about an axis of the workpiece (W); a pressing device (14) configured to press a periphery of the workpiece (W) against the annular polishing surface (2a); and an operation controller (25) configured to change a speed at which the rotating device (15) rotates the workpiece (W) according to a rotation angle of the workpiece (W). The pressing device (14) is disposed more inwardly than the workpiece holder (11) in a radial direction of the polishing table (3).

A magnetic-disk glass substrate containing an alkali metal component as a glass composition includes a pair of main surfaces and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface with a roughness percentage that is 40% or more when a bearing ratio of a roughness cross-sectional area is 50%, in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained by etching the outer circumferential side edge surface by 2.5 μm is measured.

A truing device for truing a grinding tool having a specified grinding profile, includes at least one first truing region and a second truing region connected thereto. The first truing region has a first specification for sharpening the grinding profile of the grinding tool and the second truing region has a second specification, different from the first specification, for restoring the grinding profile of the grinding tool. The first truing region has a greater volume than the second truing region, the truing device has a longitudinal axis, the two truing regions are arranged one behind the other in the direction of the longitudinal axis, and the truing device is substantially cuboid.

The method for machining a glass pane (1), wherein the edge (1a) of the glass pane is machined using at least one grinding tool (10), in that the glass pane and the grinding tool, which is set in rotation by means of a motor (11), are moved relative to one another, includes a method step in which a variable that is a function of the power consumption of the motor (11) used to drive the grinding tool is detected along at least a section of the edge (1a) being machined, and is evaluated to determine the offset of the glass pane (1) with respect to a target position (1).

A polishing apparatus capable of forming a step-shaped recess having a right-angled cross section in an edge portion of a substrate, such as a wafer, is disclosed. The polishing apparatus includes: a substrate rotating device configured to rotate the substrate about a rotation axis; a first roller having a first circumferential surface configured to press a polishing tape against the edge portion of the substrate; and a second roller having a second circumferential surface in contact with the first circumferential surface. The second roller has a tape stopper surface that restricts movement of the polishing tape in a direction away from the rotation axis. The tape stopper surface is located radially outward of the first circumferential surface.

The present invention relates to a chemical mechanical polishing (CMP) apparatus for polishing a workpiece, such as a metal body, to a mirror finish. The chemical mechanical polishing apparatus includes: a polishing pad (2) having an annular polishing surface (2a) which has a curved vertical cross-section; a workpiece holder (11) for holding a workpiece (W) having a polygonal shape; a rotating device (15) configured to rotate the workpiece holder (11) about an axis of the workpiece (W); a pressing device (14) configured to press a periphery of the workpiece (W) against the annular polishing surface (2a); and an operation controller (25) configured to change a speed at which the rotating device (15) rotates the workpiece (W) according to a rotation angle of the workpiece (W). The pressing device (14) is disposed more inwardly than the workpiece holder (11) in a radial direction of the polishing table (3).

A magnetic-disk glass substrate containing an alkali metal component as a glass composition includes a pair of main surfaces and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface with a roughness percentage that is 40% or more when a bearing ratio of a roughness cross-sectional area is 50%, in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained by etching the outer circumferential side edge surface by 2.5 m is measured.

A glass-plate working apparatus 1 includes a feeding section 7, a scribing and bend-breaking section 8, a grinding section 9, and a discharging section 10. The feeding section 7, the scribing and bend-breaking section 8, the grinding section 9, and the discharging section 10 are provided by being arranged from a right end R side toward a left end L side, and the scribing and bend-breaking section 8 is adapted to effect the formation of a scribe line on a glass plate 2 and the bend-breaking and separation of the glass plate 2 along the scribe line in a state in which the glass plate 2 is fixed as it is at the same position.