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 spectrum-based endpointing. An endpointing method includes selecting a reference spectrum. The 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 spectrum is empirically selected for particular spectrum-based endpoint determination logic so that the target thickness is achieved when endpoint is called by applying the particular spectrum-based endpoint logic. The method includes obtaining a current spectrum. The 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. The determining is based on the reference and current spectra.

Abstract: A polishing system receives one or more target parameters for a selected peak in a spectrum of light, polishes a substrate, measures a current spectrum of light reflected from the substrate while the substrate is being polished, identifies the selected peak in the current spectrum, measures one or more current parameters of the selected peak in the current spectrum, compares the current parameters of the selected peak to the target parameters, and ceases to polish the substrate when the current parameters and the target parameters have a pre defined relationship.

Abstract: A polishing pad is described that has a polishing layer with a polishing surface, an adhesive layer on a side of the polishing layer opposite the polishing layer, and a solid light-transmitting window extending through and molded to the polishing layer. The window has a top surface coplanar with the polishing surface and a bottom surface coplanar with a lower surface of the adhesive layer. A method of making a polishing pad includes forming an aperture through a polishing layer and an adhesive layer, securing a backing piece to the adhesive layer on a side opposite a polishing surface of the polishing layer, dispensing a liquid polymer into the aperture, and curing the liquid polymer to form a window.

Abstract: A window of solid light-transmissive polymer is formed in a polishing pad, and at least one surface of the window is treated to increase the smoothness of the at least one surface. Treating the surface of the window can include heating the at least one surface and pressing with a solid rigid part.

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 controlling polishing includes polishing a substrate, during polishing monitoring the substrate with an in-situ monitoring system, the monitoring including generating a signal from a sensor, and filtering the signal to generate a filtered signal. The signal includes a sequence of measured values, and the filtered signal including a sequence of adjusted values. The filtering includes for each adjusted value in the sequence of adjusted values, generating at least one predicted value from the sequence of measured values using linear prediction, and calculating the adjusted value from the sequence of measured values and the predicted value. At least one of a polishing endpoint or an adjustment for a polishing rate is determined from the filtered signal.

Abstract: Methods of determining a polishing endpoint are described using spectra obtained during a polishing sequence. In particular, techniques for using only desired spectra, faster searching methods and more robust rate determination methods are described.

Abstract: A method of controlling a polishing operation includes polishing a substrate, during polishing obtaining a sequence over time of measured spectra from the substrate with an in-situ optical monitoring system, for each measured spectrum from the sequence of measured spectra applying a Fourier transform to the measured spectrum to generate a transformed spectrum thus generating a sequence of transformed spectra, for each transformed spectrum identifying a peak of interest from a plurality of peaks in the transformed spectrum, for each transformed spectrum determining a position value for the peak of interest in the transformed spectrum thus generating a sequence of position values, and determining at least one of a polishing endpoint or an adjustment of a pressure to the substrate from the sequence of position values.

Abstract: A method of controlling polishing includes receiving user input through a graphical user interface selecting a function, the function including at least one parameter that can be varied, 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 the function to the sequence of values, the fitting including determining a value of the at least one parameter that provides a best fit of the function to the sequence of values, determining a projected time at which the function equals 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 a polishing operation includes polishing a substrate, during polishing obtaining a sequence over time of measured spectra from the substrate with an in-situ optical monitoring system, for each measured spectrum from the sequence of measured spectra applying a Fourier transform to the measured spectrum to generate a transformed spectrum thus generating a sequence of transformed spectra, for each transformed spectrum identifying a peak of interest from a plurality of peaks in the transformed spectrum, for each transformed spectrum determining a position value for the peak of interest in the transformed spectrum thus generating a sequence of position values, and determining at least one of a polishing endpoint or an adjustment of a pressure to the substrate from the sequence of position values.

Abstract: A polishing pad is described that has a polishing layer with a polishing surface, an adhesive layer on a side of the polishing layer opposite the polishing layer, and a solid light-transmitting window extending through and molded to the polishing layer. The window has a top surface coplanar with the polishing surface and a bottom surface coplanar with a lower surface of the adhesive layer. A method of making a polishing pad includes forming an aperture through a polishing layer and an adhesive layer, securing a backing piece to the adhesive layer on a side opposite a polishing surface of the polishing layer, dispensing a liquid polymer into the aperture, and curing the liquid polymer to form a window.

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: A method of controlling a polishing operation includes polishing a first layer of a substrate, during polishing, obtaining a sequence over time of measured spectra with an in-situ optical monitoring system, for each measured spectrum from the sequence of measured spectra, fitting an optical model to the measured spectrum, the fitting including finding parameters that provide a minimum difference between an output spectrum of the optical model and the measured spectrum, the parameters including an endpoint parameter and at least one non-endpoint parameter, the fitting generating a sequence of fitted endpoint parameter values, each endpoint parameter value of the sequence associated with one of the spectra of the sequence of measured spectra, and determining at least one of a polishing endpoint or an adjustment of a pressure to the substrate from the sequence of fitted endpoint parameter values.

Abstract: Methods and apparatus for spectrum-based endpointing. An endpointing method includes selecting a reference spectrum. The 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 spectrum is empirically selected for particular spectrum-based endpoint determination logic so that the target thickness is achieved when endpoint is called by applying the particular spectrum-based endpoint logic. The method includes obtaining a current spectrum. The 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. The determining is based on the reference and current spectra.

Abstract: A computer-implemented method includes receiving a sequence of current spectra of reflected light from a substrate; comparing each current spectrum from the sequence of current spectra to a plurality of reference spectra from a reference spectra library to generate a sequence of best-match reference spectra; determining a goodness of fit for the sequence of best-match reference spectra; and determining at least one of whether to adjust a polishing rate or an adjustment for the polishing rate, based on the goodness of fit.

Abstract: A system method and apparatus to monitor a frictional coefficient of a substrate undergoing polishing is described. A polishing pad assembly includes a polishing layer including a polishing surface, and a substrate contacting member flexibly coupled to the polishing layer having a top surface to contact an exposed surface of a substrate. At least a portion of the top surface is substantially coplanar with the polishing surface. A sensor is provided to measure a lateral displacement of the substrate contacting member. Some embodiments may provide accurate endpoint detection during chemical mechanical polishing to indicate the exposure of an underlying layer.

Abstract: A polishing pad has an opaque polishing layer with an aperture therethrough and a polishing surface, and a solid light-transmissive window in the aperture. The solid light-transmissive window includes an outer portion secured to the polishing layer and an inner portion secured to the outer portion. The outer portion has a upper surface recessed relative to the polishing surface, whereas the inner portion has an upper surface that is substantially co-planar with the polishing surface.

Abstract: A polishing system includes a polishing pad having a solid light-transmissive window, an optical fiber having an end, and a spacer having a vertical aperture therethrough. A bottom surface of the spacer contacts the end of the optical fiber, a top surface of the spacer contacts the underside of the window, and the vertical aperture is aligned with the optical fiber.