Abstract: A method of measuring flare in an optical lithographic system utilizes an exposure mask with first and second discrete opaque features each having rotational symmetry of order greater than four and of different respective areas. The exposure mask is positioned in the lithographic system such that actinic radiation emitted by the lithographic system illuminates the sensitive surface of an exposure target through the exposure mask. The extent to which regions of the sensitive surface that are within the geometric image of a feature of the exposure mask are exposed to actinic radiation during due to flare is measured.

Abstract: Computational models of a patterning process are described. Any one of these computational models can be implemented as computer-readable program code embodied in computer-readable media. The embodiments described herein explain techniques that can be used to adjust parameters of these models according to measurements, as well as how predictions made from these models can be used to correct lithography data. Corrected lithography data can be used to manufacture a device, such as an integrated circuit.

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: The present invention relates to a method of investigating the wall (2) of a borehole in a geological formation by means of two injectors (4, 5) with a potential V being applied between them and in measuring the potential difference ?V between two electrically isolated measurement electrodes (6) situated between the two injectors (4, 5) and spaced apart from the formation by an insulating layer (1), in which the resistivity of the formation is obtained from the measured values of ?V, V and I, with corrections being made for the effects due to the nature and the thickness of the insulating layer (1). In a first variant these corrections are based on a correction factor obtained from curves of K=Rt.I/?V as a function of the impedance V/I of the injector. In a second variant these corrections are obtained by estimating the current IF actually injected into the formation while taking account of leakage current IL, and calculating the resistivity of the formation from the equation (I).

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: An overlay target includes two pairs of test patterns used to measure overlay in x and y directions, respectively. Each test pattern includes upper and lower grating layers. A single pitch (periodic spacing) is used for all gratings. Within each test pattern, the upper and lower grating layers are laterally offset from each other to define an offset bias. Each pair of test patterns has offset biases that differ by the grating pitch/4. This has the important result that the combined optical response of the test patterns is sensitive to overlay for all values of overlay. An algorithm obtains overlay and other physical properties of the two or more test patterns from their optical responses in one combined regression operation.

Abstract: The invention is a method and apparatus for determining characteristics of a sample. The system and method provide for detecting a monitor beam reflected off a mirror, where the monitor beam corresponds to the intensity of light incident upon the sample. The system and method also provide for detecting a measurement beam, where the measurement beam has been reflected off the sample being characterized. Both the monitor beam and the measurement beam are transmitted through the same transmission path, and detected by the same detector. Thus, potential sources of variations between the monitor beam and the measurement beam which are not due to the characteristics of the sample are minimized. Reflectivity information for the sample can be determined by comparing data corresponding to the measurement beam relative to data corresponding the monitor beam.

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.

Abstract: A method for measuring overlay in a sample includes obtaining an image of an overlay target that includes a series of grating stacks each having an upper and lower grating, each grating stack having a unique offset between its upper and lower grating. The image is obtained with a set of illumination and collection optics where the numerical aperture of the collection optics is larger than the numerical aperture of the illumination optics and with the numerical apertures of the illumination and collection optics are selected so that the unit cells of gratings are not resolved, the grating stacks are resolved and they appear to have a uniform color within the image of the overlay target.

Abstract: A method for measuring overlay in semiconductor wafers includes a calibration phase in which a series of calibration samples are analyzed. Each calibration sample has an overlay that is known to be less than a predetermined limit. A difference spectrum for a pair of reflectively symmetric overlay targets is obtained for each calibration sample. The difference spectra are then combined to define a gross overlay indicator. In subsequent measurements of actual wafers, difference spectra are compared to the overlay indicator to detect cases of gross overlay.

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.

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: A phase-sensitive interferometeric broadband reflectometer includes an illumination source for generating an optical beam. A beam splitter or other optical element splits the optical beam into probe beam and reference beam portions. The probe beam is reflected by a subject under test and then rejoined with the reference beam. The combination of the two beams creates an interference pattern that may be modulated by changing the length of the path traveled by the probe or reference beams. The combined beam is received and analyzed by a spectrometer.

Abstract: The invention is a method and apparatus for determining characteristics of a sample. The system and method provide for detecting a monitor beam reflected off a mirror, where the monitor beam corresponds to the intensity of light incident upon the sample. The system and method also provide for detecting a measurement beam, where the measurement beam has been reflected off the sample being characterized. Both the monitor beam and the measurement beam are transmitted through the same transmission path, and detected by the same detector. Thus, potential sources of variations between the monitor beam and the measurement beam which are not due to the characteristics of the sample are minimized. Reflectivity information for the sample can be determined by comparing data corresponding to the measurement beam relative to data corresponding the monitor beam.

Abstract: A high vertical resolution antenna design is provided for use in an NMR measurement apparatus. Multiple coils are situated along the length of a magnet. A primary coil is energized to cause an oscillating magnetic field in a portion of earth formation surrounding a borehole. A secondary coil having smaller dimensions than the primary coil is operated to receive spin echoes from a depth of investigation associated with the secondary coil. A distance sufficient to minimize electrical coupling separates the coils. The separation distance can be reduced by selecting a secondary coil with orthogonal polarization to the primary coil. Alternatively, a cross coil configuration can be implemented where the orthogonal secondary coil at least partially overlaps the primary coil, thereby reducing the overall length necessary for the polarizing magnet.

Abstract: An optical measurement system for evaluating a sample has a azimuthally rotatable measurement head. A motor-driven rotating mechanism is coupled to the measurement head to allow the optics to rotate with respect to the sample. In particular, a preferred embodiment is a polarimetric scatterometer (FIG. 1) for measuring optical properties of a periodic structure on a wafer sample (12). This scatterometer has optics (30) directing a polarized illumination beam at non-normal incidence onto the periodic structure. In addition to a polarizer (8), the illumination path can also be provided with an E-O modulator for modulating the polarization. The measurement head optics also collect light reflected from the periodic structure and feed that light to a spectrometer (17) for measurement. A polarization beamsplitter (18) is provided in the collection path so that both S and P polarization from the sample can be separately measured.

Abstract: A method for measuring overlay in semiconductor wafers includes obtaining diffraction based and imaging based measurements of the same target. The two separate measurements are then combined in a way that is consistent to both measurements to obtain an overlay measurement that has high precision and large range.

Abstract: A spectroscopic ellipsometer having a multiwavelength light source, spectrometer (or wavelength-scanning monochromator and photodetector), a polarizer and polarization analyzer, and one or more objectives in the illumination and collection light paths, further comprises a stationary polarization modulator that modulates the light polarization versus wavelength. Modulator can be an optically active crystal rotating the linear polarization plane by a different angle for each wavelength or a non-achromatic waveplate retarder that varies the relative phase delay of the polarization components periodically over wavelength. The measured spectrum can be used to characterize selected features or parameters of a sample, e.g. by comparison with one or more theoretical spectra.

Abstract: The invention is a method and apparatus for determining characteristics of a sample. The system and method provide for detecting a monitor beam reflected off a mirror, where the monitor beam corresponds to the intensity of light incident upon the sample. The system and method also provide for detecting a measurement beam, where the measurement beam has been reflected off the sample being characterized. Both the monitor beam and the measurement beam are transmitted through the same transmission path, and detected by the same detector. Thus, potential sources of variations between the monitor beam and the measurement beam which are not due to the characteristics of the sample are minimized. Reflectivity information for the sample can be determined by comparing data corresponding to the measurement beam relative to data corresponding the monitor beam.

Abstract: A method for optically inspecting and evaluating a semiconductor wafer includes projecting a probe beam at two overlay targets. Each overlay target includes an upper grating and a lower grating. At each target, the combined intensity of the 1st diffracted orders generated by the upper and lower gratings are measured. The combined intensity of the −1st diffracted orders generated by the upper and lower gratings are also measured for each target. The method then calculates an overlay offset between an upper layer and a lower layer as a function of the measured intensity information.