Abstract: A method of controlling polishing includes polishing a substrate having a second layer overlying a first layer, detecting exposure of the first layer with an in-situ monitoring system, receiving an identification of a selected spectral feature and a characteristic of the selected spectral feature to monitor during polishing, measuring a sequence of spectra of light from the substrate while the substrate is being polished, determining a first value for the characteristic of the feature at the time that the first in-situ monitoring technique detects exposure of the first layer, adding an offset to the first value to generate a second value, and monitoring the characteristic of the feature and halting polishing when the characteristic of the feature is determined to reach the second value.

Abstract: A chemical-mechanical polishing apparatus including a table top, a transfer station mounted on the table top, a plurality of polishing stations mounted on the table top, a plurality of washing stations, and a plurality of carrier heads supported by a support member rotatable about an axis. Each washing station is located between a first polishing station and either a second polishing station or the transfer station, and the transfer station and the plurality of polishing stations are arranged at approximately equal angular intervals about the axis.

Abstract: A method of generating reference spectra includes polishing a first substrate in a polishing apparatus, measuring a sequence of spectra from the first substrate during polishing with an in-situ optical monitoring system, for each spectrum in the sequence of spectra, determining a best matching reference spectrum from a first plurality of first reference spectra to generate a sequence of reference spectra, calculating a value of a metric of fit of the sequence of spectra to the sequence of reference spectra, comparing the value of the metric of fit to a threshold value and determining whether to generate a second library based on the comparison, and if the second library is determined to be generated, storing the sequence of spectra as a second plurality of reference spectra.

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.

Abstract: A substrate having a plurality of zones is polished and spectra are measured. For each zone, a first linear function fits a sequence of index values associated with reference spectra that best match the measured spectra. A projected time at which a reference zone will reach the target index value is determined based on the first linear function, and for at least one adjustable zone, a polishing parameter adjustment is calculated such that the adjustable zone has closer to the target index at the projected time than without such adjustment. The adjustment is calculated based on a feedback error calculated for a previous substrate. The feedback error for a subsequent substrate is calculated based on a second linear function that fits a sequence of index values associated with reference spectra that best match spectra measured after the polishing parameter is adjusted.

Abstract: A plurality of substrates are polished simultaneously on the same polishing pad. A sequence of spectra is measured from each zone of each substrate, and for each measured spectrum in the sequence of spectra for each zone of each substrate, a best matching reference spectrum is determined from a library of reference spectra. For each zone of each substrate, a linear function is fit to a sequence of index values associated with the best matching reference spectra. For at least one zone, a projected time at which the zone will reach a target index value is determined based on the linear function, and the polishing parameter for at least one zone on at least one substrate is adjusted such that the at least one zone of the at least one substrate has closer to the target index at the projected time than without such adjustment.

Abstract: A method of controlling polishing includes polishing a substrate and receiving an identification of a selected spectral feature, a wavelength range having a width, and a characteristic of the selected spectral feature to monitor during polishing. A sequence of spectra of light from the substrate is measured while the substrate is being polished. A sequence of values of the characteristic of the selected spectral feature is generated from the sequence of spectra. For at least some spectra from the sequence of spectra, a modified wavelength range is generated based on a position of the spectral feature within a previous wavelength range used for a previous spectrum in the sequence of spectra, the modified wavelength range is searched for the selected spectral feature, and a value of a characteristic of the selected spectral feature is determined.

Abstract: A method of optically monitoring a substrate during polishing includes receiving an identification of a selected spectral feature and a characteristic of the selected spectral feature to monitor during polishing, measuring a first spectrum from the substrate during polishing, the first spectrum measured within an initial time following initiation of polishing, measuring a sequence of second spectra from the substrate during polishing, the sequence of second spectra measured after the initial time, for each second spectrum in the sequence of second spectra, removing the first spectrum from the second spectrum to generate a sequence of modified third spectra, determining a value of a characteristic of the selected spectral feature for each third spectrum in the sequence of third spectra to generate a sequence of values for the characteristic, and determining a polishing endpoint or an adjustment for a polishing rate based on the sequence of values.

Abstract: A computer-implemented method of generating reference spectra includes polishing a first substrate in a polishing apparatus having a rotatable platen, measuring a sequence of spectra from the substrate during polishing with an in-situ monitoring system, associating each spectrum in the sequence of spectra with a index value equal to a number of platen rotations at which the each spectrum was measured, and storing the sequence of spectra as reference spectra.

Abstract: A method of controlling polishing includes polishing a substrate, monitoring a substrate during polishing with an in-situ monitoring system, generating a sequence of values from measurements from the in-situ monitoring system, fitting a non-linear function to the sequence of values, determining a projected time at which the non-linear function reaches a target value; and determining at least one of a polishing endpoint or an adjustment for a polishing rate based on the projected time.

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: 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.

Abstract: A substrate processing system includes a processing module to process a substrate, a factory interface module configured to accommodate at least one cassette for holding the substrate, a spectrographic monitoring system positioned in or adjoining the factory interface module, and a substrate handler to transfer the substrate between the at least one cassette, the spectrographic monitoring system and the processing module.

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 generating a library from a reference substrate for use in processing product wafers is described. The method includes measuring substrate characteristics at a plurality of well-defined points of a reference substrate, measuring spectra at plurality of measurement points of the reference substrate, there being more measurement points than well-defined points, and associating measured spectra with measured substrate characteristics.

Abstract: A method includes polishing a substrate on a first platen using a first set of parameters, obtaining a plurality of measured spectra from at least two zones, comparing the plurality of measured spectra with a reference spectrum to evaluate the thickness of each of the at least two zones of the substrate, comparing a thickness of a first zone with a thickness of a second zone, determining whether the thickness of the first zone falls within a predetermined range of the thickness of the second zone, and if the thickness does not fall within the predetermined range, at least one of a) adjusting at least one parameter of the first set and polishing a second substrate on the first platen using the adjusted parameters, or b) adjusting at least one parameter of a second set and polishing the substrate on a second platen using the adjusted parameters.

Abstract: A method of generating a library from a reference substrate for use in processing product wafers is described. The method includes measuring substrate characteristics at a plurality of well-defined points of a reference substrate, measuring spectra at plurality of measurement points of the reference substrate, there being more measurement points than well-defined points, and associating measured spectra with measured substrate characteristics.

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.

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 program product that determines a polishing endpoint includes obtaining spectra from different zones on a substrate during different times in a polishing sequence, matches the spectra with indexes in a library and uses the indexes to determining a polishing rate for each of the different zones from the indexes. An adjusted polishing rate can be determined for one of the zones, which causes the substrate to have a desired profile when the polishing end time is reached.