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.

An end effector for a robotic sanding system includes a sanding head including a sander configured to sand a surface of a workpiece. A motor is operatively coupled to the sander. The motor is configured to rotate the sander to sand the surface of the workpiece. The motor includes a first central longitudinal axis. A coupler is configured to removably secure the end effector to an attachment interface of an arm of the robotic sanding system. The coupler includes a second central longitudinal axis. The first central longitudinal axis is offset from the second central longitudinal axis. One or more sensors are coupled to the sanding head. The one or more sensors are configured to detect presence of a metal within the predefined range.

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.

A body is brought into contact with a polishing pad of a polishing system, a polishing liquid is supplied to the polishing pad, relative motion between the body and the polishing pad is generated while the body contacts the polishing pad, a signal from an in-situ eddy current monitoring system during the relative motion while the body contacts the polishing pad, generating, and mechanical vibrations in the polishing system are detected based on a signal from the in-situ eddy current monitoring system.

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.

An output of an eddy current sensor includes an impedance component. A film thickness measuring apparatus obtains film thickness information from the impedance component. Using a non-linear function between the film thickness information and the film thickness, the film thickness is obtained from the film thickness information. When a resistance component and a reactance component of the impedance component are associated with respective axes of a coordinate system having two orthogonal coordinate axes, the film thickness information is a reciprocal of a tangent of an impedance angle which is an angle formed by a straight line connecting a point on the coordinate system corresponding to the impedance component and a predetermined reference point, and a predetermined straight line.

To specify a trajectory of an eddy current sensor provided on a polishing table of a substrate polishing apparatus, disclosed is a method of identifying a trajectory of an eddy current sensor as seen from a substrate in a substrate polishing apparatus having a polishing table and a polishing head. The method includes: obtaining a sensor output map as three-dimensional data; polishing the substrate; obtaining a profile of the real-time polishing signal as two-dimensional data; and extracting a trajectory having a profile most similar to the profile of the real-time polishing signal as two-dimensional data from the sensor output map as three-dimensional data and identifying the extracted trajectory as a trajectory of the eddy current sensor as seen from the substrate.

To measure thickness in a polishing treatment more efficiently. A substrate polishing apparatus comprises a rotatably configured polishing table provided with a sensor that outputs a signal related to a thickness, a rotatably configured polishing head that faces the polishing table, a substrate being attachable to a face of the polishing head that faces the polishing table, and a controller. The controller acquires a signal from the sensor when the sensor passes over a surface to be polished of the substrate, specifies an orbit of the sensor with respect to the substrate on a basis of a profile of the signal, calculates a thickness of the substrate at each point on the orbit on a basis of the signal, and creates a thickness map on a basis of the calculated thickness at each point on a plurality of orbits of the sensor.

An eddy current sensor has an exciting coil and a detection coil. A holding circuit holds reference data indicating a characteristic of an output signal output from the detection coil at a reference state and outputs the reference data at a state other than the reference state. A pseudo signal generating circuit generates and outputs a balance coil pseudo signal corresponding to the output signal output from the detection coil at the reference state from the reference data output from the holding circuit. A bridge circuit, at the state other than the reference state, receives the output signal output from the detection coil and the balance coil pseudo signal and outputs a bridge output signal corresponding to a difference between the output signal and the balance coil pseudo signal as a bridge output signal.

During polishing of a stack of adjacent conductive layers on a substrate, an in-situ eddy current monitoring system measures sequence of characterizing values. A polishing rate is repeatedly calculated from the sequence of characterizing values repeatedly, one or more adjustments for one or more polishing parameters are repeatedly calculated based on a current polishing rate using a first control algorithm for an initial time period, a change in the polishing rate that meets at least one first predetermined criterion that indicates exposure of the underlying conductive layer is detected, and one or more adjustments for one or more polishing parameters are calculated based on the polishing rate using a different second control algorithm for a subsequent time period after detecting the change in the polishing rate.