Abstract: An apparatus for chemical mechanical polishing includes a support for a polishing pad having a polishing surface, and an electromagnetic induction monitoring system to generate a magnetic field to monitor a substrate being polished by the polishing pad. The electromagnetic induction monitoring system includes a core and a coil wound around a portion of the core. The core includes a back portion, a center post extending from the back portion in a first direction normal to the polishing surface, and an annular rim extending from the back portion in parallel with the center post and surrounding and spaced apart from the center post by a gap. A width of the gap is less than a width of the center post, and a surface area of a top surface of the annular rim is at least two times greater than a surface area of a top surface of the center post.

Abstract: A chemical mechanical polishing apparatus includes a platen to support a polishing pad, the platen having a recess, a flexible membrane in the recess, and an in-situ vibration monitoring system to generate a signal. The in-situ acoustic monitoring system includes a vibration sensor supported by the flexible membrane and positioned to couple to an underside of the polishing pad.

Abstract: An apparatus for chemical mechanical polishing includes a support for a polishing pad having a polishing surface, and an electromagnetic induction monitoring system to generate a magnetic field to monitor a substrate being polished by the polishing pad. The electromagnetic induction monitoring system includes a core and a coil wound around a portion of the core. The core includes a back portion, a center post extending from the back portion in a first direction normal to the polishing surface, and an annular rim extending from the back portion in parallel with the center post and surrounding and spaced apart from the center post by a gap. A width of the gap is less than a width of the center post, and a surface area of a top surface of the annular rim is at least two times greater than a surface area of a top surface of the center post.

Abstract: A method of detecting a polishing endpoint includes storing a plurality of library spectra, measuring a sequence of spectra from the substrate in-situ during polishing, and for each measured spectrum of the sequence of spectra, finding a best matching library spectrum from the plurality of library spectra to generate a sequence of best matching library spectra. Each library spectrum has a stored associated value representing a degree of progress through a polishing process, and the stored associated value for the best matching library spectrum is determined for each best matching library spectrum to generate a sequence of values representing a progression of polishing of the substrate. The sequence of values is compared to a target value, and a polishing endpoint is triggered when the sequence of values reaches the target value.

Abstract: A system for obtaining a measurement representative of a thickness of a layer on a substrate includes a support to hold a substrate, an optical assembly to capture two color images with light impinging the substrate at different angles of incidence, and a controller. The controller is configured to store a function that provides a value representative of a thickness as a function of position along a predetermined path in a coordinate space of at least four dimensions. For a pixel in the two color images, the controller determines a coordinate in the coordinate space from the color data, determines a position of a point on the predetermined path that is closest to the coordinate, and calculates a value representative of a thickness from the function and the position of the point on the predetermined path.

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 detecting a polishing endpoint includes storing a plurality of library spectra, measuring a sequence of spectra from the substrate in-situ during polishing, and for each measured spectrum of the sequence of spectra, finding a best matching library spectrum from the plurality of library spectra to generate a sequence of best matching library spectra. Each library spectrum has a stored associated value representing a degree of progress through a polishing process, and the stored associated value for the best matching library spectrum is determined for each best matching library spectrum to generate a sequence of values representing a progression of polishing of the substrate. The sequence of values is compared to a target value, and a polishing endpoint is triggered when the sequence of values reaches the target value.

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 substrate for use in fabrication of an integrated circuit has a layer with a plurality of conductive interconnects. The substrate includes a semiconductor body, a dielectric layer disposed over the semiconductor body, a plurality of conductive lines of a conductive material disposed in first trenches in the dielectric layer to provide the conductive interconnects, and a closed conductive loop structure of the conductive material disposed in second trenches in the dielectric layer. The closed conductive loop is not electrically connected to any of the conductive lines.

Abstract: In fabrication of an integrated circuit having a layer with a plurality of conductive interconnects, a layer of a substrate is polished to provide the layer of the integrated circuit. The layer of the substrate includes conductive lines to provide the conductive interconnects. The layer of the substrate includes a closed conductive loop formed of a conductive material in a trench. A depth of the conductive material in the trench is monitored using an inductive monitoring system and a signal is generated. Monitoring includes generating a magnetic field that intermittently passes through the closed conductive loop. A sequence of values over time is extracted from the signal, the sequence of values representing the depth of the conductive material over time.

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: A method of polishing a layer on the substrate at a polishing station includes the actions of monitoring the layer during polishing at the polishing station with an in-situ monitoring system to generate a plurality of measured signals for a plurality of different locations on the layer; generating, for each location of the plurality of different locations, an estimated measure of thickness of the location, the generating including processing the plurality of measured signals through a neural network; and at least one of detecting a polishing endpoint or modifying a polishing parameter based on each estimated measure of thickness.

Abstract: An eddy current monitoring system may include an elongated core. One or more coils may be coupled with the elongated core for producing an oscillating magnetic field that may couple with one or more conductive regions on a wafer. The core may be translated relative to the wafer to provide improved resolution while maintaining sufficient signal strength. An eddy current monitoring system may include a DC-coupled marginal oscillator for producing an oscillating magnetic field at a resonant frequency, where the resonant frequency may change as a result of changes to one or more conductive regions. Eddy current monitoring systems may be used to enable real-time profile control.

Abstract: In fabrication of an integrated circuit having a layer with a plurality of conductive interconnects, a layer of a substrate is polished to provide the layer of the integrated circuit. The layer of the substrate includes conductive lines to provide the conductive interconnects. The layer of the substrate includes a closed conductive loop formed of a conductive material in a trench. A depth of the conductive material in the trench is monitored using an inductive monitoring system and a signal is generated. Monitoring includes generating a magnetic field that intermittently passes through the closed conductive loop. A sequence of values over time is extracted from the signal, the sequence of values representing the depth of the conductive material over time.

Abstract: A plurality of spectra reflected from one or more substrates at a plurality of different positions on the one or more substrates are represented in the form of a first matrix, and the first matrix is decomposed into products of at least two component matrixes of a first set of component matrixes. The dimensions of each of the at least two component matrixes is reduced to produce a second set of component matrixes containing the at least two matrixes with reduced dimensions.

Abstract: A first resistivity value and a correlation function relating thickness of a conductive layer having the first resistivity value to a signal from an in-situ monitoring system are stored. A second resistivity value for a conductive layer on a substrate is received. A sequence of signal values that depend on thickness of the conductive layer is received from an in-situ electromagnetic induction monitoring system that monitors the substrate during polishing. A sequence of thickness values is generated based on the sequence of signal values and the correlation function. For at least some thickness values of the sequence of thickness values adjusted thickness values are generated that compensate for variation between the first resistivity value and the second resistivity value to generate a sequence of adjusted thickness values. A polishing endpoint is detected or an adjustment for a polishing parameter is determined based on the sequence of adjusted thickness values.

Abstract: A first resistivity value and a correlation function relating thickness of a conductive layer having the first resistivity value to a signal from an in-situ monitoring system are stored. A second resistivity value for a conductive layer on a substrate is received. A sequence of signal values that depend on thickness of the conductive layer is received from an in-situ electromagnetic induction monitoring system that monitors the substrate during polishing. A sequence of thickness values is generated based on the sequence of signal values and the correlation function. For at least some thickness values of the sequence of thickness values adjusted thickness values are generated that compensate for variation between the first resistivity value and the second resistivity value to generate a sequence of adjusted thickness values. A polishing endpoint is detected or an adjustment for a polishing parameter is determined based on the sequence of adjusted thickness values.

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: A substrate for use in fabrication of an integrated circuit has a layer with a plurality of conductive interconnects. The substrate includes a semiconductor body, a dielectric layer disposed over the semiconductor body, a plurality of conductive lines of a conductive material disposed in first trenches in the dielectric layer to provide the conductive interconnects, and a closed conductive loop structure of the conductive material disposed in second trenches in the dielectric layer. The closed conductive loop is not electrically connected to any of the conductive lines.

Abstract: An apparatus for chemical mechanical polishing includes a platen having a surface to support a polishing pad and an electromagnetic induction monitoring system to generate a magnetic field to monitor a substrate being polished by the polishing pad. The electromagnetic induction monitoring system includes a core positioned at least partially in the platen and a coil wound around a portion of the core. The core includes a back portion and a multiplicity of posts extending from the back portion in a first direction normal to the surface of the platen. The core and coil are configured such that the multiplicity of posts include a first plurality of posts to provide a first magnetic polarity and a second plurality of posts to provide an opposite second magnetic polarity, and the first plurality of posts and the second plurality of posts are arranged in an alternating pattern.