A measurement system for use in measuring parameters of a patterned sample, the system including a broadband light source, an optical system configured as an interferometric system, a detection unit, and a control unit, where the interferometric system defines illumination and detection channels having a sample arm and a reference arm having a reference reflector, and is configured for inducing an optical path difference between the sample and reference arms, the detection unit for detecting a combined light beam formed by a light beam reflected from the reflector and a light beam propagating from a sample's support, and generating measured data indicative of spectral interference pattern formed by spectral interference signatures, and the control unit for receiving the measured data and applying a model-based processing to the spectral interference pattern for determining one or more parameters of the pattern in the sample.

A low-coherence interferometer apparatus for determining information on interfaces of an object including: a polychromatic light source; an optical system generating a measurement optical beam and a reference optical beam; a delay line introducing a variable optical delay between the optical beams; detection optics combining the beams, and producing a spectral signal representative of an optical-power spectral density of the resulting interference signal; a control and processing module acquiring a plurality of spectral signals for a plurality of optical delays, determining, for each spectral signal, optical retardation information between interfering beams within a spectral measurement range, analyse the variation in the retardations, and assign the optical retardation determined on the basis of the different spectral signals to interface curves, corresponding to straight lines with positive, negative, zero or almost-zero gradient, depending on the respective optical delay of the acquisition of the spectral signals, and to deduce information of the object.

Apparatus and methods are described for performing tear film structure measurement on a tear film of an eye of a subject. A broadband light source (100) is configured to generate broadband light. A spectrometer (250) is configured to measure a spectrum of light of the broadband light that is reflected from at least one spot on the tear film, the spot having a diameter of between 100 microns and 240 microns. A computer processor (28) is coupled to the spectrometer and configured to determine a characteristic of the tear film based upon the spectrum of light measured by the spectrometer. Other applications are also described.

An interferometer having a fundamental beam generator, a first second harmonic generator, a waveplate, a second second harmonic generator, a harmonic separator, and a polarizing beam splitter, mounted uniaxially, (i.e., the components are aligned along one optical axis), wherein the interferometer is adapted to change a diameter of a beam to match a diameter of a sample, and to change the diameter of the beam back to its original diameter.

A controller is configured to perform at least a first characterization process prior to at least one discrete backside film deposition process on a semiconductor wafer; perform at least an additional characterization process following the at least one discrete backside film deposition process; determine at least one of a film force or one or more in-plane displacements for at least one discrete backside film deposited on the semiconductor wafer via the at least one discrete backside film deposition process based on the at least the first characterization process and the at least the additional characterization process; and provide at least one of the film force or the one or more in-plane displacements to at least one process tool via at least one of a feed forward loop or a feedback loop to improve performance of one or more fabrication processes.

The present invention relates to an apparatus and a method for measuring a thickness and a refractive index of a multilayer thin film using an angle-resolved spectral interference image according to polarization. More specifically, the present invention relates to an apparatus for measuring a thickness and a refractive index of a multilayer thin film using an angle-resolved spectral interference image according to polarization in an apparatus for measuring a thickness and a refractive index of a measurement object coated with the multilayer thin film, the apparatus including: an illumination optical module having a light source emitting light; a first beam splitter configured to reflect some of the light emitted from the illumination optical module; an objective lens configured to input some of the light reflected from the first beam splitter to the measurement object constituted by the multilayer thin film and reflect the remaining light to a reference plane to form interference light on a back focal plane; a second beam splitter in which interference light where the reflected light incident and reflected to the measurement object interferes with the reflected light reflected from the reference plane is incident, wherein some of the interference light is reflected and the remaining interference light is transmitted; a first angle-resolved spectral image acquiring unit configured to receive interference light reflected from the second beam splitter and first-polarize the interference light located in the back focal plane of the objective lens to acquire a first polarized interference image; and a second angle-resolved spectral image acquiring unit configured to receive interference light transmitted from the second beam splitter and second-polarize the interference light located in the back focal plane of the objective lens to acquire a second polarized interference image.

A thickness measuring apparatus for measuring the thickness of a workpiece held on a chuck table includes the followings: a light source configured to emit white light; an optical branching unit configured to branch, to a second optical path, reflected light applied from the light source to the workpiece held on the chuck table via a first optical path and reflected from the workpiece; a diffraction grating disposed in the second optical path; an image sensor configured to detect an optical intensity signal of light separated into each wavelength by the diffraction grating; and a thickness output unit configured to generate a spectral interference waveform on the basis of the optical intensity signal detected by the image sensor, determine the thickness on the basis of the spectral interference waveform, and output the thickness.

The present disclosure relates to an apparatus and method for measuring the thickness and refractive index of a multilayer thin film by measuring angle-resolved spectral reflectance according to light polarization. According to an exemplary embodiment of the present disclosure, the apparatus and method for measuring the thickness and refractive index of a multilayer structure using angle-resolved spectroscopic reflectometry is capable of measuring and analyzing thickness and refractive index of each layer of a structure having a multilayer thin film through an s-polarized imaging and a p-polarized imaging of the reflective light located in a back focal plane of an objective lens which are acquired through an angle-resolved spectral imaging acquisition part.

A method of identifying the material and determining the physical thickness of each layer in a multilayer structure is disclosed. The method includes measuring the optical thickness of each of the layers of the multilayer object as a function of wavelength of a light source and calculating a normalized group index of refraction dispersion curve for each layer in the multilayer structure. The measured normalized group index of refraction dispersion curves for each of the layers is then compared to a reference database of known materials and the material of each layer is identified. The physical thickness of each layer is then determined from the group index of refraction dispersion curve for the material in each layer and the measured optical thickness data. A method for determining the group index of refraction dispersion curve of a known material, and an apparatus for performing the methods are also disclosed.

A method for determining material removal by an ion beam (3) on a test workpiece (7) which is disposed in a machining chamber (5) of a housing (6) of a device (1) for beam machining, wherein the test workpiece (7) has a substrate (8) and a layer (9) applied to the substrate. The method includes a) optically determining a layer thickness (d1) of the layer applied to the substrate, b) removing material of the layer from the test workpiece with the ion beam, c) optically determining the layer thickness (d2) of the layer applied to the substrate, and d) determining the material removal by comparing the layer thickness determined in step a) with the layer thickness determined in step c). Also disclosed is a device (1) for beam machining a workpiece (2) with which the method can be carried out.