Abstract:
A method including: obtaining a measurement of a metrology target on a substrate processed using a patterning process, the measurement having been obtained using measurement radiation; and deriving a parameter of interest of the patterning process from the measurement, wherein the parameter of interest is corrected by a stack difference parameter, the stack difference parameter representing an un-designed difference in physical configuration between adjacent periodic structures of the target or between the metrology target and another adjacent target on the substrate.
Abstract:
A method of determining a position of an imprint template in an imprint lithography apparatus is disclosed. In an embodiment, the method includes illuminating an area of the imprint template in which an alignment mark is expected to be found by scanning an alignment radiation beam over that area, detecting an intensity of radiation reflected or transmitted from the area, and identifying the alignment mark via analysis of the detected intensity.
Abstract:
Apparatus, systems, and methods are used for detecting the alignment of a feature on a substrate using a polarization independent interferometer. The apparatus, system, and methods include optical elements that receive light that has diffracted or scattered from a mark on a substrate. The optical elements may split the diffracted light into multiple subbeams of light which are detected by one or more detectors. The diffracted light may be combined optically or during processing after detection. The system may determine alignment and/or overlay based on the received diffracted light having any polarization angle or state.
Abstract:
Metrology targets are formed on a substrate (W) by a lithographic process. A target (T) comprising one or more grating structures is illuminated with spatially coherent radiation under different conditions. Radiation (650) diffracted by from said target area interferes with reference radiation (652) interferes with to form an interference pattern at an image detector (623). One or more images of said interference pattern are captured. From the captured image(s) and from knowledge of the reference radiation a complex field of the collected scattered radiation at the detector. A synthetic radiometric image (814) of radiation diffracted by each grating is calculated from the complex field. From the synthetic radiometric images (814, 814′) of opposite portions of a diffractions spectrum of the grating, a measure of asymmetry in the grating is obtained. Using suitable targets, overlay and other performance parameters of the lithographic process can be calculated from the measured asymmetry.
Abstract:
Disclosed herein is a computer-implemented defect prediction method for a device manufacturing process involving processing a portion of a design layout onto a substrate, the method comprising: identifying a hot spot from the portion of the design layout; determining a range of values of a processing parameter of the device manufacturing process for the hot spot, wherein when the processing parameter has a value outside the range, a defect is produced from the hot spot with the device manufacturing process; determining an actual value of the processing parameter; determining or predicting, using the actual value, existence, probability of existence, a characteristic, or a combination thereof, of a defect produced from the hot spot with the device manufacturing process.
Abstract:
In a method of determining the focus of a lithographic apparatus used in a lithographic process on a substrate, the lithographic process is used to form a structure on the substrate, the structure having at least one feature which has an asymmetry in the printed profile which varies as a function of the focus of the lithographic apparatus on the substrate. A first image of the periodic structure is formed and detected while illuminating the structure with a first beam of radiation. The first image is formed using a first part of non-zero order diffracted radiation. A second image of the periodic structure is formed and detected while illuminating the structure with a second beam of radiation. The second image is formed using a second part of the non-zero order diffracted radiation which is symmetrically opposite to the first part in a diffraction spectrum. The ratio of the intensities of the measured first and second portions of the spectra is determined and used to determine the asymmetry in the profile of the periodic structure and/or to provide an indication of the focus on the substrate. In the same instrument, an intensity variation across the detected portion is determined as a measure of process-induced variation across the structure. A region of the structure with unwanted process variation can be identified and excluded from a measurement of the structure.
Abstract:
A sensor apparatus includes a sensor chip, an illumination system, a first optical system, a second optical system, and a detector system. The illumination system is coupled to the sensor chip and transmits an illumination beam along an illumination path. The first optical system is coupled to the sensor chip and includes a first integrated optic to configure and transmit the illumination beam toward a diffraction target on a substrate, disposed adjacent to the sensor chip, and generate a signal beam including diffraction order sub-beams generated from the diffraction target. The second optical system is coupled to the sensor chip and includes a second integrated optic to collect and transmit the signal beam from a first side to a second side of the sensor chip. The detector system is configured to measure a characteristic of the diffraction target based on the signal beam transmitted by the second optical system.
Abstract:
Disclosed is a method of improving a measurement of a parameter of interest. The method comprises obtaining metrology data comprising a plurality of measured values of the parameter of interest, relating to one or more targets on a substrate, each measured value relating to a different measurement combination of a target of said one or more targets and a measurement condition used to measure that target and asymmetry metric data relating to asymmetry for said one or more targets. A respective relationship is determined for each of said measurement combinations relating a true value for the parameter of interest to the asymmetry metric data, based on an assumption that there is a common true value for the parameter of interest over said measurement combinations. These relationships are used to improve a measurement of the parameter of interest.
Abstract:
Disclosed is an illumination arrangement for spectrally shaping a broadband illumination beam to obtain a spectrally shaped illumination beam. The illumination arrangement comprises a beam dispersing element for dispersing the broadband illumination beam and a spatial light modulator for spatially modulating the broadband illumination beam subsequent to being dispersed. The illumination arrangement further comprises at least one of a beam expanding element for expanding said broadband illumination beam in at least one direction, located between an input of the illumination arrangement and the spatial light modulator; and a lens array, each lens of which for directing a respective wavelength band of the broadband illumination beam subsequent to being dispersed onto a respective region of the spatial light modulator.
Abstract:
Described is a metrology system for determining a characteristic of interest relating to at least one structure on a substrate, and associated method. The metrology system comprises a processor being configured to computationally determine phase and amplitude information from a detected characteristic of scattered radiation having been reflected or scattered by the at least one structure as a result of illumination of said at least one structure with illumination radiation in a measurement acquisition, and use the determined phase and amplitude to determine the characteristic of interest.