Abstract: A method of chemical mechanical polishing a substrate includes polishing a plurality of discrete separated metal features of a layer on the substrate at a polishing station, using an eddy current monitoring system to monitor thickness of the metal features in the layer, and controlling pressures applied by a carrier head to the substrate during polishing of the layer at the polishing station based on thickness measurements of the metal features from the eddy current monitoring system to reduce differences between an expected thickness profile of the metal feature and a target profile.

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 halting polishing when the eddy current monitoring system indicates that residue of the metal layer is removed from an underlying layer and a top surface of the underlying layer is exposed.

Abstract: A computer-implemented method of generating reference spectra includes polishing a plurality of set-up substrates, the plurality of set-up substrates comprising at least three set-up substrates, measuring a sequence of spectra from each of the plurality of set-up substrates during polishing with an in-situ optical monitoring system to provide a plurality of sequences of spectra, generating a plurality of sequences of potential reference spectra from the plurality of sequences of spectra, determining which sequence of potential reference spectra of the plurality of sequences provides a best match to remaining sequences of the plurality of sequences, and storing the sequence of potential reference spectra determined to provide the best match as reference spectra, and selecting and storing the sequence of potential reference spectra.

Abstract: A computer-implemented method includes polishing substrates simultaneously in a polishing apparatus. Each substrate has a polishing rate independently controllable by an independently variable polishing parameter. Measurement data that varies with the thickness of each of the substrates is acquired from each of the substrates during polishing with an in-situ monitoring system. A projected thickness that each substrate will have at a target time is determined based on the measurement data. The polishing parameter for at least one substrate is adjusted to adjust the polishing rate of the at least one substrate such that the substrates have closer to the same thickness at the target time than without the adjustment.

Abstract: A method of controlling the polishing of a substrate includes polishing a substrate on a first platen using a first set of parameters, obtaining first and second sequences of measured spectra from first and second regions of the substrate with an in-situ optical monitoring system, generating first and second sequences of values from the first and second sequences of measured spectra, fitting first and second linear functions to the first and second sequences of values, determining a difference between the first linear function and the second linear function, adjusting at least one parameter of the first set of parameters based on the difference, and polishing the second substrate on the first platen using the adjusted parameter.

Abstract: A chemical mechanical polishing pad is described. A chemical mechanical polishing pad has an outer layer that includes a polishing surface, a first thinned region defined by a recess on a bottom surface of the pad, a first thick region surrounding the first thinned region, a second thinned region surrounding the first thick region, and a second thick region surrounding the second thinned region. The first thick region is not vertically extendable. The second thinned region defines one or more flexure mechanisms configured to make the first thinned region and the first thick region movable relative to the second thick region in a direction parallel or substantially parallel to the polishing surface.

Abstract: An apparatus for monitoring the thickness of a conductive layer on a substrate includes a support to hold a substrate having a conductive layer, an eddy current monitoring system including a first plurality of core portions, and a motor to cause relative motion between the support and the eddy current monitoring system such that the substrate moves across the first plurality of core portions in a direction that defines a first axis. At least one core portion is positioned further from a second axis than at least two other core portions. The second axis is orthogonal to the first axis.

Abstract: Methods and apparatus for automatic gain control. A film on a substrate is polished by a chemical mechanical polisher that includes a polishing pad and an in-situ monitoring system. The polishing pad includes a first portion, and the in-situ monitoring system includes a light source and a light detector. The light source emits light, and light emitted from the light source is directed through the first portion and to a surface of the film being polished. Light reflecting from the surface of the film being polished and passing through the first portion is received at the light detector. An electronic signal is generated based on the light received at the light detector. When the electronic signal is evaluated not to satisfy one or more constraints, a gain for the light detector is adjusted so that the electronic signal would satisfy the one or more constraints.

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 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: Methods and apparatus for automatic gain control. A film on a substrate is polished by a chemical mechanical polisher that includes a polishing pad and an in-situ monitoring system. The polishing pad includes a first portion, and the in-situ monitoring system includes a light source and a light detector. The light source emits light, and light emitted from the light source is directed through the first portion and to a surface of the film being polished. Light reflecting from the surface of the film being polished and passing through the first portion is received at the light detector. An electronic signal is generated based on the light received at the light detector. When the electronic signal is evaluated not to satisfy one or more constraints, a gain for the light detector is adjusted so that the electronic signal would satisfy the one or more constraints.

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 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 difference between a first expected required polish time for a first substrate and a second expected required polish time for a second substrate is determined using a first pre-polish thickness and a second pre-polish thickness measured at an in-line metrology station. A duration of an initial period is determined based on the difference between the first expected required polish time and the second expected required polish time. For the initial period at a beginning of a polishing operation, no pressure is applied to whichever of the first substrate and the second substrate has a lesser expected required polish time while simultaneously pressure is applied to whichever of the first substrate and the second substrate has a greater expected required polish time. After the initial period, pressure is applied to both the first substrate and the second substrate.

Abstract: Systems, methods and apparatus are provided for determining a substrate polishing endpoint. The invention includes a light source adapted to transmit light to an edge of a substrate; one or more detectors adapted to detect an arrangement of light reflected from the substrate edge; and a controller adapted to determine a polishing endpoint for the substrate edge based on the arrangement of reflected light. Numerous other aspects are provided.

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 method of controlling the polishing of a substrate includes polishing a substrate on a first platen using a first set of parameters, obtaining first and second sequences of measured spectra from first and second regions of the substrate with an in-situ optical monitoring system, generating first and second sequences of values from the first and second sequences of measured spectra, fitting first and second linear functions to the first and second sequences of values, determining a difference between the first linear function and the second linear function, adjusting at least one parameter of a second set of parameters based on the difference, and polishing the substrate on a second platen using the adjusted parameter.

Abstract: Methods and apparatus for spectrum-based endpointing. An endpointing method includes selecting two or more reference spectra. Each reference spectrum is a spectrum of white light reflected from a film of interest on a first substrate and has a thickness greater than a target thickness. The reference spectra is selected for particular spectra-based endpoint determination logic so that the target thickness is achieved when endpoint is called by applying the particular spectra-based endpoint logic. The method includes obtaining two or more current spectra. Each current spectrum is a spectrum of white light reflected from a film of interest on a second substrate when the film of interest is being subjected to a polishing step and has a current thickness that is greater than the target thickness. The method includes determining, for the second substrate, when an endpoint of the polishing step has been achieved.

Abstract: A polishing method includes simultaneously polishing two substrates, a first substrate and a second substrate, on the same polishing pad. A default overpolishing time is stored and an in-situ monitoring system monitors the two substrates. The in-situ monitoring system further determines a first polishing endpoint time and a second polishing endpoint time of the first and second substrates, respectively. The polishing method further includes calculating an overpolishing stop time where the overpolishing stop time is between the first polishing endpoint time plus the default overpolishing time and the second polishing endpoint time plus the default overpolishing time. Polishing of the first substrate is continued past the first polishing endpoint time and polishing of the second substrate is continued past the second polishing endpoint time. Polishing of both the first substrate and the second substrate is halted simultaneously at the overpolishing stop time.

Abstract: A method of determining a physical property of a substrate includes recording a first spectrum obtained from a substrate, the first spectrum being obtained during a polishing process that alters a physical property of the substrate. The method includes identifying, in a database, at least one of several previously recorded spectra that is similar to the recorded first spectrum. Each of the spectra in the database has a physical property value associated therewith. The method includes generating a signal indicating that a first value of the physical property is associated with the first spectrum, the first value being determined using the physical property value associated with the identified previously recorded spectrum in the database. A system for determining a physical property of a substrate includes a polishing machine, an endpoint determining module, and a database.