The sum of torques: the torque of the sun gear and the torque of the internal gear, and the ratio of the torques are controlled within predetermined ranges.

An indium phosphide substrate, a method of inspecting thereof and a method of producing thereof are provided, by which an epitaxial film grown on the substrate is rendered excellently uniform, thereby allowing improvement in PL characteristics and electrical characteristics of an epitaxial wafer formed using this epitaxial film. The indium phosphide substrate has a first main surface and a second main surface, a surface roughness Ra1 at a center position on the first main surface, and surface roughnesses Ra2, Ra3, Ra4, and Ra5 at four positions arranged equidistantly along an outer edge of the first main surface and located at a distance of 5 mm inwardly from the outer edge. An average value m1 of the surface roughnesses Ra1, Ra2, Ra3, Ra4, and Ra5 is 0.5 nm or less, and a standard deviation σ1 of the surface roughnesses Ra1, Ra2, Ra3, Ra4, and Ra5 is 0.2 nm or less.

An embodiment comprises: a lower plate; an upper plate which is disposed on the lower plate and rotates; a carrier which receives a wafer and is disposed on the lower plate; and a sensor unit for irradiating light to the wafer received in the carrier, detecting light reflected by the wafer, and outputting detection data according to the detection result, wherein the sensor unit rotates together with the upper plate.

An embodiment comprises: a lower plate; an upper plate which is disposed on the lower plate and rotates; a carrier which receives a wafer and is disposed on the lower plate; and a sensor unit for irradiating light to the wafer received in the carrier, detecting light reflected by the wafer, and outputting detection data according to the detection result, wherein the sensor unit rotates together with the upper plate.

A method for raising a polishing pad for polishing a silicon wafer, wherein a polishing pad made of foamed urethane resin is attached to a polishing machine, after dressing is performed, dummy polishing is performed, after processing to remove the polishing residues that have built up in the polishing pad by the dummy polishing is then performed, an amount of polishing residues in the polishing pad is measured, and a rise of the polishing pad subjected to the dummy polishing is judged based on the measured amount of polishing residues. As a result, a method for raising a polishing pad can improve the particle level in the polishing pad life early stage.

A method for raising a polishing pad for polishing a silicon wafer, wherein a polishing pad made of foamed urethane resin is attached to a polishing machine, after dressing is performed, dummy polishing is performed, after processing to remove the polishing residues that have built up in the polishing pad by the dummy polishing is then performed, an amount of polishing residues in the polishing pad is measured, and a rise of the polishing pad subjected to the dummy polishing is judged based on the measured amount of polishing residues. As a result, a method for raising a polishing pad can improve the particle level in the polishing pad life early stage.

A machining apparatus for a workpieces includes an upper turn table support mechanism supporting an upper turn table from above to be vertically movable by a cylinder extending along a rotational axis direction of the table, a horizontal plate fixed to the cylinder so that a main surface thereof becomes perpendicular to a longitudinal axis of the cylinder, at least three displacement sensors which measure horizontal plate surface height positions when the upper turn table has moved down to a fixed position, and a control apparatus to calculate a relative upper turn table height position and an angle formed between the upper turn table rotational axis and the cylinder longitudinal axis from the horizontal plate surface height positions measured by the displacement sensors. A workpiece holding abnormality can be accurately and quickly detected before machining the workpiece to avoid damage, and an cylinder eccentric angle can be detected during machining.

A machining apparatus for a workpieces includes an upper turn table support mechanism supporting an upper turn table from above to be vertically movable by a cylinder extending along a rotational axis direction of the table, a horizontal plate fixed to the cylinder so that a main surface thereof becomes perpendicular to a longitudinal axis of the cylinder, at least three displacement sensors which measure horizontal plate surface height positions when the upper turn table has moved down to a fixed position, and a control apparatus to calculate a relative upper turn table height position and an angle formed between the upper turn table rotational axis and the cylinder longitudinal axis from the horizontal plate surface height positions measured by the displacement sensors. A workpiece holding abnormality can be accurately and quickly detected before machining the workpiece to avoid damage, and an cylinder eccentric angle can be detected during machining.

A workpiece to be ground by a grinding wheel of a grinding apparatus has a first layer including a first material and a second layer including a second material that is harder to grind than the first material and stacked on the first layer. The rotational speed of the grinding wheel for grinding the second layer, i.e., a second rotational speed, is lower than the rotational speed of the grinding wheel for grinding the first layer, i.e., a first rotational speed. The second layer can thus be ground effectively, as it is not necessary to use a grinding wheel with a high grinding capability or to lower a rate at which the workpiece is ground. Consequently, it is possible to maintain productivity for device chips manufactured by dividing the workpiece, and also prevent the footprint of the grinding apparatus from increasing.

A double-disc straight groove cylindrical-component surface grinding disc, includes a first grinding disc and a second grinding disc, rotating relative to each other; the the first grinding disc's working face is planar; the second grinding disc's surface, opposite the first grinding disc, includes a set of radial straight grooves, with groove faces of the straight grooves are the working face of the second grinding disc; the cross-sectional outline of the working face of the second grinding disc is arcuate or V-shaped or is a V-shape having an arc; during grinding, a workpiece spins inside the straight grooves, while under the effect of an advancing apparatus, the workpiece slides in translational motion along the straight grooves. The described grinding disc device has high-volume production capabilities, and the shape accuracy and size consistency of the cylindrical roller's cylindrical surface and the efficiency in machining are improved, and machining cost is reduced.