A method of controlling polishing includes polishing a substrate at a first polishing station, monitoring the substrate with a first eddy current monitoring system to generate a first signal, determining an ending value of the first signal for an end of polishing of the substrate at the first polishing station, determining a first temperature at the first polishing station, polishing the substrate at a second polishing station, monitoring the substrate with a second eddy current monitoring system to generate a second signal, determining a starting value of the second signal for a start of polishing of the substrate at the second polishing station, determining a gain for the second polishing station based on the ending value, the starting value and the first temperature, and calculating a third signal based on the second signal and the gain.

Implementations described herein generally relate to methods and apparatus for polishing substrates, more particularly, to methods and apparatus for identifying and/or tracking polishing material in a roll-to-roll polishing system. In one implementation, a method of polishing a substrate is provided. The method comprises advancing a polishing material across a surface of a platen. The polishing material has a polishing surface and an opposing backside surface and the backside surface has a pattern of identifying features formed thereon. The method further comprises sensing the movement of the pattern of identifying features past a detector assembly. The method further comprises controlling a position of the polishing material relative to the platen based on data received from the sensed movement of the pattern of identifying features.

A polishing apparatus comprises a dresser that can adjust swing speed in the scanning areas set on a polishing member along a swing direction, a height detection section that measures a surface height of the polishing member in a plurality of monitoring areas set on the polishing member along the swing direction of the dresser, a dress model matrix creation section that creates a dress model matrix defined from a plurality of monitoring areas, scanning areas and a dress model, an evaluation index creation section that calculates a height profile predicted value using the dress model, the swing speed in each scanning area or a staying time and sets evaluation index based on a difference from a target value of height profile of the polishing member and a moving speed calculation section that calculates the swing speed in each scanning area of the dresser based on the evaluation index.

The polishing apparatus has: a polishing pad that has a polishing surface to polish a semiconductor wafer; a polishing table to which a back surface of the polishing pad on an opposite side of the polishing surface can be attached; a top ring that is opposed to the polishing surface, and can hold the semiconductor wafer; and an eddy current sensor that is arranged in the polishing table, and detects an end point of polishing. The polishing table has on an attachment surface a projection member projecting from the attachment surface to which the polishing pad is attached. The back surface of the polishing pad has a concave portion in a portion opposed to the projection member, and at least a part of the eddy current sensor is arranged inside the projection member.

A floor grinder (100) for processing a concrete surface (101), the floor grinder comprising one or more rotatable abrasive tool holders (150) arranged in a plane (P) to hold respective abrasive tools (210, 510), at least one power source (110, 120) arranged to drive the tool holders (150), a cover body (130) fixedly arranged in relation to the plane (P), and a dust skirt (140) movably attached around a rim of the cover body (130) to engage the concrete surface (101) during floor grinding operation, where the floor grinder (100) comprises at least one tool wear indicator (160) configured to indicate a current tool wear based on a displacement of the dust skirt (140) relative to the cover body (130) in a direction (D) normal to the plane (P).

A surface processing apparatus comprises a surface processing device to process a surface, a robot to move the surface processing device with respect to the surface, an electromagnetic actuator to electromagnetically apply an actuator force to the surface processing device, so as to cause the surface processing device to press against the surface with a controlled pressing force, and a control unit to control the pressing force by adjusting an electric current of the electromagnetic actuator.

A method of polishing a substrate includes polishing a conductive layer on the substrate at a polishing station, monitoring the layer with an in-situ eddy current monitoring system to generate a plurality of measured signals values for a plurality of different locations on the layer, generating thickness measurements the locations, and detecting a polishing endpoint or modifying a polishing parameter based on the thickness measurements. The conductive layer is formed of a first material having a first conductivity. Generating includes calculating initial thickness values based on the plurality of measured signals values and processing the initial thickness values through a neural network that was trained using training data acquired by measuring calibration substrates having a conductive layer formed of a second material having a second conductivity that is lower than the first conductivity to generated adjusted thickness values.

Eddy current formable in a polishing target is detected as an impedance by an eddy current sensor. A resistance component and a reactance component of the impedance are associated with respective axes of a coordinate system having orthogonal axes, respectively. An angle calculator calculates the tangent of an intersection angle between a first straight line connecting a first point corresponding to an impedance for a zero film thickness, and a second point corresponding to an impedance for a non-zero film thickness, and a diameter of a circle passing through the first point. A film thickness calculator determines the film thickness from the tangent.

In a first step, an output of an eddy current sensor is measured while a polishing target whose film thickness has been known is in contact with the polishing face, thereby obtaining a measurement value of the eddy current sensor which corresponds to the film thickness. In a second step, an output of the eddy current sensor is measured when the polishing target is polished while pressed against the polishing face, thereby obtaining a measurement value of the eddy current sensor that corresponds to a film thickness during polishing. A correspondence relationship between the film thickness of the polishing target and the measurement value of the eddy current sensor is determined from the measurement value obtained in the first step and the measurement value obtained in the second step.

An eddy current monitoring system may include an elongated core. One or more coils may be coupled with the elongated core for producing an oscillating magnetic field that may couple with one or more conductive regions on a wafer. The core may be translated relative to the wafer to provide improved resolution while maintaining sufficient signal strength. An eddy current monitoring system may include a DC-coupled marginal oscillator for producing an oscillating magnetic field at a resonant frequency, where the resonant frequency may change as a result of changes to one or more conductive regions. Eddy current monitoring systems may be used to enable real-time profile control.