Abstract: A substrate polishing system includes a platen to support a polishing surface, a carrier head configured to hold a substrate against the polishing surface during polishing, a light source configured to direct a light beam onto a surface of the substrate, a detector including an array of detection elements, and a controller. The detector is configured to detect reflections of the light beam from an area of the surface, and is configured to generate an image having pixels representing regions on the substrate having a length less than 0.1 mm. The controller is configured to receive the image and to detect clearance of a metal layer from an underlying layer on the substrate based on the image.

Abstract: During polishing of a first substrate at a first polishing station, a sequence of measurements by a first in-situ monitoring system is monitored to determining a first time at which the first sequence exhibits a first predefined feature indicating a predetermined thickness of an overlying layer, and during polishing of the first substrate at a second polishing station, a sequence of measurements by a second in-situ monitoring system is monitored to determine a second time indicating clearance of the overlying layer and exposure of the underlying layer. The first time is used to calculate a first adjusted polishing pressure for a second substrate at the first polishing station, and the second time is used to calculate a second adjusted polishing pressure for the second substrate at the second polishing station.

Abstract: A method of controlling polishing includes polishing a first substrate having an overlying layer on an underlying layer or layer structure. During polishing, the substrate is monitored with an in-situ monitoring system to generate a sequence of measurements. The measurements are sorted into groups, each group associated with a different zone of a plurality of zones on the substrate. For each zone, a time at which the overlying layer is cleared is determined based on the measurements from the associated group. At least one second adjusted polishing pressure for at least zone is calculated based on a pressure applied in the at least one zone during polishing the substrate, the time for the at least one zone, and the time for another zone. A second substrate is polished using the at least one adjusted polishing pressure.

Abstract: A method of operating a polishing system includes polishing a substrate at a polishing station, the substrate held by a carrier head during polishing, transporting the substrate to an in-sequence optical metrology system positioned between the polishing station and another polishing station or a transfer station, measuring a plurality of spectra reflected from the substrate with a probe of the optical metrology system while moving the carrier head to cause the probe to traverse a path across the substrate and while the probe remains stationary, the path across the substrate comprising either a plurality of concentric circles or a plurality of substantially radially aligned arcuate segments, and adjusting a polishing endpoint or a polishing parameter of the polishing system based on one or more characterizing values generated based on at least some of the plurality of spectra.

Abstract: In one aspect, a method of polishing includes polishing a substrate, and receiving an identification of a selected spectral feature and a characteristic of the selected spectral feature to monitor during polishing. The method includes measuring a sequence of spectra of light reflected from the substrate while the substrate is being polished, where at least some of the spectra of the sequence differ due to material being removed during the polishing. The method of polishing includes determining a value of a characteristic of the selected spectral feature for each of the spectra in the sequence of spectra to generate a sequence of values for the characteristic, fitting a function to the sequence of values, and determining either a polishing endpoint or an adjustment for a polishing rate based on the function.

Abstract: A method of chemical mechanical polishing a substrate includes polishing a metal layer on the substrate at a polishing station, monitoring thickness of the metal layer during polishing at the polishing station with an eddy current monitoring system, and controlling pressures applied by a carrier head to the substrate during polishing of the metal layer at the polishing station based on thickness measurements of the metal layer from the eddy current monitoring system to reduce differences between an expected thickness profile of the metal layer and a target profile, wherein the metal layer has a resistivity greater than 700 ohm Angstroms.

Abstract: Among other things, a computer-based method is described. The method comprises receiving, by one or more computers, a plurality of measured spectra reflected from a substrate at a plurality of different positions on the substrate. The substrate comprises at least two regions having different structural features. The method also comprises performing, by the one or more computers, a clustering algorithm on the plurality of measured spectra to separate the plurality of measured spectra into a number of groups based on the spectral characteristics of the plurality of measured spectra; selecting one of the number of groups to provide a selected group having a subset of spectra from the plurality of measured spectra; and determining, in the one or more computers, at least one characterizing value for the substrate based on the subset of spectra of the selected group.

Abstract: Among other things, a machine based method comprises representing a plurality of spectra reflected from one or more substrates at a plurality of different positions on the one or more substrates in the form of a first matrix; decomposing, by one or more computers, the first matrix into products of at least two component matrixes of a first set of component matrixes; reducing dimensions of each of the at least two component matrixes to produce a second set of component matrixes containing the at least two matrixes with reduced dimensions; and generating, by the one or more computers, a second matrix by taking a product of the matrixes of the second set of component matrixes.

Abstract: In one aspect, a method of controlling polishing includes receiving a measurement of an initial thickness of a conductive film on a first substrate prior to polishing the first substrate from an in-line or stand-alone monitoring system, polishing one or more substrates in a polishing system, the one or more substrates including the first substrate, during polishing of the one or more substrates, monitoring the one or more substrates with an eddy current monitoring system to generate a first signal, determining a starting value of the first signal for a start of polishing of the first substrate, determining a gain based on the starting value and the measurement of the initial thickness, for at least a portion of the first signal collected during polishing of at least one substrate of the one or more substrates, and calculating a second signal based on the first signal and the gain.

Abstract: 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.

Abstract: A method of controlling a polishing operation includes measuring a plurality of spectra at a plurality of different positions on a substrate to provide a plurality of measured spectra. For each measured spectrum of the plurality of measured spectra, a characterizing value is generated based on the measured spectrum. For each characterizing value, a goodness of fit of the measured spectrum to another spectrum used in generating the characterizing value is determined. A wafer-level characterizing value map is generated by applying a regression to the plurality of characterizing values with the plurality of goodnesses of fit used as weighting factors in the regression. A polishing endpoint or a polishing parameter of the polishing apparatus is adjusted based on the wafer-level characterizing map, and the substrate or a subsequent substrate is polished in the polishing apparatus with the adjusted polishing endpoint or polishing parameter.

Abstract: In polishing a substrate having a layer of GST disposed over an underlying layer, during polishing, a non-polarized light beam is directed onto the layer of GST. The non-polarized light beam reflects from the first substrate to generate a reflected light beam having an infra-red component. A sequence of measurements of intensity of the infra-red component of the reflected light beam are generated, and, in a processor, a time at which the sequence of measurements exhibits a predefined feature is determined.

Abstract: In one aspect, a method of polishing includes polishing a substrate, and receiving an identification of a selected spectral feature and a characteristic of the selected spectral feature to monitor during polishing. The method includes measuring a sequence of spectra of light reflected from the substrate while the substrate is being polished, where at least some of the spectra of the sequence differ due to material being removed during the polishing. The method of polishing includes determining a value of a characteristic of the selected spectral feature for each of the spectra in the sequence of spectra to generate a sequence of values for the characteristic, fitting a function to the sequence of values, and determining either a polishing endpoint or an adjustment for a polishing rate based on the function.

Abstract: A method of configuring a polishing monitoring system includes receiving user input selecting a plurality of libraries, each library of the plurality of libraries comprising a plurality of reference spectra for use in matching to measured spectra during polishing, each reference spectrum of the plurality of reference spectra having an associated index value, for a first zone of a substrate, receiving user input selecting a first subset of the plurality of libraries, and for a second zone of the substrate, receiving user input selecting a second subset of the plurality of libraries.

Abstract: A polishing apparatus includes a platen to hold a polishing pad having a plurality of optical apertures, a carrier head to hold a substrate against the polishing pad, a motor to generate relative motion between the carrier head and the platen, and an optical monitoring system. The optical monitoring system includes at least one light source, a common detector, and an optical assembly configured to direct light from the at least one light source to each of a plurality of separated positions in the platen, to direct light from each position of the plurality of separated positions to the substrate as the substrate passes over said each position, to receive reflected light from the substrate as the substrate passes over said each position, and to direct the reflected light from each of the plurality of separated positions to the common detector.

Abstract: A method of forming a polishing pad with a polishing layer having a polishing surface and a back surface. A plurality of grooves are formed on the polishing surface, and an indentation is formed in the back surface of the polishing layer. A region on the polishing surface corresponding to the indentation in the back surface is free of grooves or has shallower grooves.

Abstract: Methods, systems, and apparatus for spectrographic monitoring of a substrate during chemical mechanical polishing are described. In one aspect, a computer-implemented method includes storing a library having a plurality of reference spectra, each reference spectrum of the plurality of reference spectra having a stored associated index value, measuring a sequence of spectra in-situ during polishing to obtain measured spectra, for each measured spectrum of the sequence of spectra, finding a best matching reference spectrum to generate a sequence of best matching reference spectra, determining the associated index value for each best matching spectrum from the sequence of best matching reference spectra to generate a sequence of index values, fitting a linear function to the sequence of index values, and halting the polishing either when the linear function matches or exceeds a target index or when the associated index value from the determining step matches or exceeds the target index.

Abstract: A computer implemented method of monitoring a polishing process includes, for each sweep of a plurality of sweeps of an optical sensor across a substrate undergoing polishing, obtaining a plurality of current spectra, each current spectrum of the plurality of current spectra being a spectrum resulting from reflection of white light from the substrate, for each sweep of the plurality of sweeps, determining a difference between each current spectrum and each reference spectrum of a plurality of reference spectra to generate a plurality of differences, for each sweep of the plurality of sweeps, determining a smallest difference of the plurality of differences, thus generating a sequence of smallest difference, and determining a polishing endpoint based on the sequence of smallest differences.

Abstract: A method of forming a polishing pad with a polishing layer having a polishing surface and a back surface. A plurality of grooves are formed on the polishing surface, and an indentation is formed in the back surface of the polishing layer. A region on the polishing surface corresponding to the indentation in the back surface is free of grooves or has shallower grooves.

Abstract: A method of controlling a polishing operation includes receiving a first measurement of a first amount of metal on a substrate made by a first x-ray monitoring system after a first metal layer is deposited on the substrate and before a second metal layer is deposited on the substrate, transferring the substrate to a carrier head of a chemical mechanical polishing apparatus the substrate after the second metal layer is deposited on the substrate, making a second measurement of a second amount of metal on the substrate with a second x-ray monitoring system in the chemical mechanical polishing apparatus, comparing the first measurement to the second measurement to determine a difference, and adjusting a polishing endpoint or a polishing parameter of the polishing apparatus based on the difference.