Abstract: Optical inspection methods and apparatus for high-resolution photomasks using only a test image. A filter is applied to an image signal received from radiation that is transmitted by or reflected from a photomask having a test image. The filter may be implemented using programmed control to adjust and control filter conditions, illumination conditions, and magnification conditions.

Abstract: Optical inspection methods and apparatus for high-resolution photomasks using only a test image. A filter is applied to an image signal received from radiation that is transmitted by or reflected from a photomask having a test image. The filter may be implemented using programmed control to adjust and control filter conditions, illumination conditions, and magnification conditions.

Abstract: A zoned order sorting filter for a spectrometer in a semiconductor metrology system is disclosed with reduced light dispersion at the zone joints. The order sorting filter comprises optically-transparent layers deposited underneath, or on top of thin-film filter stacks of the order sorting filter zones, wherein the thicknesses of the optically-transparent layers are adjusted such that the total optical lengths traversed by light at a zone joint are substantially equal in zones adjacent the zone joint. A method for wavelength to detector array pixel location calibration of spectrometers is also disclosed, capable of accurately representing the highly localized nonlinearities of the calibration curve in the vicinity of zone joints of an order sorting filter.

Abstract: A zoned order sorting filter for a spectrometer in a semiconductor metrology system is disclosed with reduced light dispersion at the zone joints. The order sorting filter comprises optically-transparent layers deposited underneath, or on top of thin-film filter stacks of the order sorting filter zones, wherein the thicknesses of the optically-transparent layers are adjusted such that the total optical lengths traversed by light at a zone joint are substantially equal in zones adjacent the zone joint. A method for wavelength to detector array pixel location calibration of spectrometers is also disclosed, capable of accurately representing the highly localized nonlinearities of the calibration curve in the vicinity of zone joints of an order sorting filter.

Abstract: A zoned order sorting filter for a spectrometer in a semiconductor metrology system is disclosed with reduced light dispersion at the zone joints. The order sorting filter comprises optically-transparent layers deposited underneath, or on top of thin-film filter stacks of the order sorting filter zones, wherein the thicknesses of the optically-transparent layers are adjusted such that the total optical lengths traversed by light at a zone joint are substantially equal in zones adjacent the zone joint. A method for wavelength to detector array pixel location calibration of spectrometers is also disclosed, capable of accurately representing the highly localized nonlinearities of the calibration curve in the vicinity of zone joints of an order sorting filter.

Abstract: A zoned order sorting filter for a spectrometer in a semiconductor metrology system is disclosed with reduced light dispersion at the zone joints. The order sorting filter comprises optically-transparent layers deposited underneath, or on top of thin-film filter stacks of the order sorting filter zones, wherein the thicknesses of the optically-transparent layers are adjusted such that the total optical lengths traversed by light at a zone joint are substantially equal in zones adjacent the zone joint. A method for wavelength to detector array pixel location calibration of spectrometers is also disclosed, capable of accurately representing the highly localized nonlinearities of the calibration curve in the vicinity of zone joints of an order sorting filter.

Abstract: Optical metrology tools in a fleet of optical metrology tools can be matched using transforms. In particular, a first set of measured diffraction signals is obtained. The first set of measured diffraction signals was measured using a first optical metrology tool from the fleet of optical metrology tools. A second set of measured diffraction signals is obtained. The second set of diffraction signals was measured using a second optical metrology tool from the fleet of optical metrology tools. A reference diffraction signal is obtained. A first transform is generated based on the first set of measured diffraction signals and the reference diffraction signal. A second transform is generated based on the second set of measured diffraction signals and the reference diffraction signal.

Abstract: Optical metrology tools in a fleet of optical metrology tools can be matched using transforms. In particular, a first set of hypothetical profiles of one or more structures is obtained. The first set of hypothetical profiles was determined based on a first set of measured diffraction signals measured using a first optical metrology tool from the fleet of optical metrology tools. A second set of hypothetical profiles of the structure is obtained. The second set of hypothetical profiles was determined based on a second set of measured diffraction signals measured using a second optical metrology tool from the fleet of optical metrology tools. A reference profile is obtained. A first transform is generated based on the first set of hypothetical profiles and the reference profile. A second transform is generated based on the second set of hypothetical profiles and the reference profile.

Abstract: An optical measurement system for evaluating a sample has a motor-driven rotating mechanism coupled to an azimuthally rotatable measurement head, allowing the optics to rotate with respect to the sample. A polarimetric scatterometer, having optics directing a polarized illumination beam at non-normal incidence onto a periodic structure on a sample, can measure optical properties of the periodic structure. An E-O modulator in the illumination path can modulate the polarization. The head optics collect light reflected from the periodic structure and feed that light to a spectrometer for measurement. A beamsplitter in the collection path can ensure both S and P polarization from the sample are separately measured. The measurement head can be mounted for rotation of the plane of incidence to different azimuthal directions relative to the periodic structures. The instrument can be integrated within a wafer process tool in which wafers may be provided at arbitrary orientation.

Abstract: Optical metrology tools in a fleet of optical metrology tools can be matched using transforms. In particular, a first set of measured diffraction signals is obtained. The first set of measured diffraction signals was measured using a first optical metrology tool from the fleet of optical metrology tools. A second set of measured diffraction signals is obtained. The second set of diffraction signals was measured using a second optical metrology tool from the fleet of optical metrology tools. A reference diffraction signal is obtained. A first transform is generated based on the first set of measured diffraction signals and the reference diffraction signal. A second transform is generated based on the second set of measured diffraction signals and the reference diffraction signal.

Abstract: Optical metrology tools in a fleet of optical metrology tools can be matched using transforms. In particular, a first set of hypothetical profiles of one or more structures is obtained. The first set of hypothetical profiles was determined based on a first set of measured diffraction signals measured using a first optical metrology tool from the fleet of optical metrology tools. A second set of hypothetical profiles of the structure is obtained. The second set of hypothetical profiles was determined based on a second set of measured diffraction signals measured using a second optical metrology tool from the fleet of optical metrology tools. A reference profile is obtained. A first transform is generated based on the first set of hypothetical profiles and the reference profile. A second transform is generated based on the second set of hypothetical profiles and the reference profile.

Abstract: A small-spot imaging, spectrometry instrument for measuring properties of a sample has a polarization-scrambling element, such as a birefringent plate depolarizer, incorporated between the polarization-introducing components of the system, such as the beamsplitter, and the microscope objective of the system. The plate depolarizer varies polarization with wavelength, and may be a Lyot depolarizer with two plates, or a depolarizer with more than two plates (such as a three-plate depolarizer). Sinusoidal perturbation in the resulting measured spectrum can be removed by data processing techniques or, if the depolarizer is thick or highly birefringent, the perturbation may be narrower than the wavelength resolution of the instrument.

Abstract: A small-spot imaging, spectrometry instrument for measuring properties of a sample has a polarization-scrambling element, such as a birefringent plate depolarizer, incorporated between the polarization-introducing components of the system, such as the beamsplitter, and the microscope objective of the system. The plate depolarizer varies polarization with wavelength, and may be a Lyot depolarizer with two plates, or a depolarizer with more than two plates (such as a three-plate depolarizer). Sinusoidal perturbation in the resulting measured spectrum can be removed by data processing techniques or, if the depolarizer is thick or highly birefringent, the perturbation may be narrower than the wavelength resolution of the instrument.

Abstract: A database interpolation method is used to rapidly calculate a predicted optical response characteristic of a diffractive microstructure as part of a real-time optical measurement process. The interpolated optical response is a continuous and (in a preferred embodiment) smooth function of measurement parameters, and it matches the theoretically-calculated optical response at the database-stored interpolation points.

Abstract: An optical measurement system for evaluating a sample has a motor-driven rotating mechanism coupled to an azimuthally rotatable measurement head, allowing the optics to rotate with respect to the sample. A polarimetric scatterometer, having optics directing a polarized illumination beam at non-normal incidence onto a periodic structure on a sample, can measure optical properties of the periodic structure. An E-O modulator in the illumination path can modulate the polarization. The head optics collect light reflected from the periodic structure and feed that light to a spectrometer for measurement. A beamsplitter in the collection path can ensure both S and P polarization from the sample are separately measured. The measurement head can be mounted for rotation of the plane of incidence to different azimuthal directions relative to the periodic structures. The instrument can be integrated within a wafer process tool in which wafers may be provided at arbitrary orientation.

Abstract: This invention is an apparatus for imaging metrology, which in particular embodiments may be integrated with a processor station such that a metrology station is apart from but coupled to a process station. The metrology station is provided with a first imaging camera with a first field of view containing the measurement region. Alternate embodiments include a second imaging camera with a second field of view. Preferred embodiments comprise a broadband ultraviolet light source, although other embodiments may have a visible or near infrared light source of broad or narrow optical bandwidth. Embodiments including a broad bandwidth source typically include a spectrograph, or an imaging spectrograph. Particular embodiments may include curved, reflective optics or a measurement region wetted by a liquid. In a typical embodiment, the metrology station and the measurement region are configured to have 4 degrees of freedom of movement relative to each other.

Abstract: A method of measuring at least one parameter associated with a portion of a sample having formed thereon one or more structures with at least two zones each having an associated zone reflectance property. The method includes the steps of illuminating the zones with broadband light, and measuring at least one reflectance property of light reflected from the at least two zones. The measurement includes a substantial portion of non-specularly scattered light, thereby increasing the quality of the measurement. The method further includes the step of fitting a parameterized model to the measured reflectance property. The parameterized model mixes the zone reflectance properties of the zones to account for partially coherent light interactions between the two zones.

Abstract: Alignment accuracy between two or more patterned layers is measured using a metrology target comprising substantially overlapping diffraction gratings formed in a test area of the layers being tested. An optical instrument illuminates all or part of the target area and measures the optical response. The instrument can measure transmission, reflectance, and/or ellipsometric parameters as a function of wavelength, polar angle of incidence, azimuthal angle of incidence, and/or polarization of the illumination and detected light. Overlay error or offset between those layers containing the test gratings is determined by a processor programmed to calculate an optical response for a set of parameters that include overlay error, using a model that accounts for diffraction by the gratings and interaction of the gratings with each others' diffracted field. The model parameters might also take account of manufactured asymmetries.