A local polishing system comprises: a particle estimation unit (30) for estimating the film thickness distribution of a wafer; a local polishing region setting unit (11) for setting a local polishing region on the wafer based on the film thickness distribution; a polishing head selection unit (12) for selecting a polishing head based on the size of the local polishing region; a model storage (20) holding a recipe generating model that defines the relation between an input node and an output node, the input node being an attribute of the local polishing region, the output node comprising a recipe for a polishing process; a polishing recipe generator (13) that puts an attribute of the local polishing region set by the local polishing region setting unit (11) into the input node of the recipe generating model and determines a polishing recipe for polishing the local polishing region; and a polishing recipe transmitter (15) for transmitting data of the polishing recipe to a local polishing module (200) that performs local polishing.

A spool-fed grinding system includes a spooling system, a grinding machine, and a computer controller. The spooling mechanism includes a spool assembly from which wire is unwound, with the spool assembly having an axis of rotation on which a spool spins to unwind the wire. The grinding machine includes a grinding wheel, a linear movement mechanism, and a rotation mechanism. The linear movement mechanism holds and linearly moves the wire along a longitudinal axis during grinding, and the rotation mechanism rotates the wire about the longitudinal axis during grinding. The axis of rotation of the spool and the longitudinal axis generally are not transverse with each other. The computer controller is programmed to control coordinated operation of the spooling mechanisms and the grinding machine, such that the spooling mechanism is controlled to rotate the spool at a same rotation speed as a rotation speed of the wire during grinding.

A spool-fed grinding system includes a spooling system, a grinding machine, and a computer controller. The spooling mechanism includes a spool assembly from which wire is unwound, with the spool assembly having an axis of rotation on which a spool spins to unwind the wire. The grinding machine includes a grinding wheel, a linear movement mechanism, and a rotation mechanism. The linear movement mechanism holds and linearly moves the wire along a longitudinal axis during grinding, and the rotation mechanism rotates the wire about the longitudinal axis during grinding. The axis of rotation of the spool and the longitudinal axis generally are not transverse with each other. The computer controller is programmed to control coordinated operation of the spooling mechanisms and the grinding machine, such that the spooling mechanism is controlled to rotate the spool at a same rotation speed as a rotation speed of the wire during grinding.

The invention provides a double-side polishing method including first polishing at a high polishing rate, second polishing at a low polishing rate, dividing a straight line extending between the outermost circumferences of the wafer through the center into prescribed sections, and optically measuring a cross-sectional shape of the sections; applying a weight predetermined for each section to the cross-sectional shape to quantify flatness of each section; and determining polishing conditions of the first and second polishing in subsequent polishing on a basis of the quantified flatness, wherein a beam diameter of a measurement apparatus used to measure the cross-sectional shape of outermost sections is smaller than that used to measure the cross-sectional shape of the other section. The method can measure the shape of the wafer up to its outermost circumference with high precision without reducing productivity, and improve the flatness of the entire wafer including its outermost circumference.

The invention provides a double-side polishing method including first polishing at a high polishing rate, second polishing at a low polishing rate, dividing a straight line extending between the outermost circumferences of the wafer through the center into prescribed sections, and optically measuring a cross-sectional shape of the sections; applying a weight predetermined for each section to the cross-sectional shape to quantify flatness of each section; and determining polishing conditions of the first and second polishing in subsequent polishing on a basis of the quantified flatness, wherein a beam diameter of a measurement apparatus used to measure the cross-sectional shape of outermost sections is smaller than that used to measure the cross-sectional shape of the other section. The method can measure the shape of the wafer up to its outermost circumference with high precision without reducing productivity, and improve the flatness of the entire wafer including its outermost circumference.

In a holding surface correction processing step, a shape of a holding surface is corrected by an etching mechanism in such a manner as to have a surface shape similar to that of an upper surface of a test grinding wafer having been ground in a test grinding step. As a result, at a time of a grinding step, when a holding section of a chuck table communicates with a suction source and a product wafer is held under suction on the holding surface, the holding surface becomes a substantially flat surface, and a radius part of the holding surface becomes parallel to a lower surface of a wafer grinding grindstone. Hence, it is possible to prevent partial thickness differences from being generated in the product wafer having been ground by the wafer grinding grindstone.

In a holding surface correction processing step, a shape of a holding surface is corrected by an etching mechanism in such a manner as to have a surface shape similar to that of an upper surface of a test grinding wafer having been ground in a test grinding step. As a result, at a time of a grinding step, when a holding section of a chuck table communicates with a suction source and a product wafer is held under suction on the holding surface, the holding surface becomes a substantially flat surface, and a radius part of the holding surface becomes parallel to a lower surface of a wafer grinding grindstone. Hence, it is possible to prevent partial thickness differences from being generated in the product wafer having been ground by the wafer grinding grindstone.

A disclosed method utilizes virtual representations of gear profiles produced in view of accuracies and capabilities of specific machine and tool combinations to validate profile finishing parameters. The virtual representations are utilized to identify modifications needed to account for process capability and are implemented into the process to change the nominal profile utilized for producing the finished gear profiles. The resulting nominal gear profile accounts for process variations and thereby provides a more accurate and repeatable gear tooth profile.

A disclosed method utilizes virtual representations of gear profiles produced in view of accuracies and capabilities of specific machine and tool combinations to validate profile finishing parameters. The virtual representations are utilized to identify modifications needed to account for process capability and are implemented into the process to change the nominal profile utilized for producing the finished gear profiles. The resulting nominal gear profile accounts for process variations and thereby provides a more accurate and repeatable gear tooth profile.

An embodiment of the present invention provides a device for measuring a wafer polishing amount, comprising: a first weighing unit for measuring the weight of a loading cassette in which wafers are accommodated before polishing; a second weighing unit for measuring the weight of an unloading cassette in which the wafers are stored after polishing; and a control unit for calculating the polishing amount of the wafers before/after polishing according to measurement values of the first and second weighing units.