Nova Ltd.

There is provided an optical measurement system that may include a control unit, an optical unit, first and second optical heads (OHs), and first and second movement units. The optical unit is configured to direct, during a first period, an illumination beam towards the second OH. The first movement unit is arranged to move, during the first period, the first OH to a first OH measurement site of a sample while the second OH participates in performing second OH metrology iterations at a second OH measurement site of the sample. The second movement unit is configured to move the second OH, during the second period, to a new second OH measurement site of the sample while the first OH participates in performing first OH metrology iterations. The or more of the first OH metrology iterations differ from each other by the polarization parameter.

Semiconductor device metrology including creating a time-domain representation of wavelength-domain measurement data of light reflected by a patterned structure of a semiconductor device, selecting an earlier-in-time portion of the time-domain representation that excludes a later-in-time portion of the time-domain representation, and determining one or more measurements of one or more parameters of interest of the patterned structure by performing model-based processing using the earlier-in-time portion of the time-domain representation.

A method for measuring characteristics of a workpiece. The method includes holding a workpiece to be tested at a specific measuring-position; forming a multi-spot-array over a test area of the workpiece, wherein said forming comprises manipulating light from at least one light source with an optical subsystem comprising a multi-spot generator; directing light emanating from the multi-spot-array towards at least one spectrometry device having an aperture; detecting Raman spectral characteristics of a plurality of spots of the multi-spot-array; and determining one or more properties of the test area of the workpiece based on the detected Raman spectral characteristics. Distribution of energy density of the multi-spot-array over the test area is configured to prevent affecting the workpiece during measurement.

A system and methods for OCD metrology are provided including receiving reference parameters, receiving multiple sets of measured scatterometric data, and receiving an optical model designed to generate one or more sets of model scatterometric data according to a set of pattern parameters, and training a machine learning model by applying, during the training, target features including the reference parameters, and by applying input features including the sets of measured scatterometric data and the sets of model scatterometric data, such that the trained machine learning model estimates new wafer pattern parameters from subsequently sets of measured scatterometric data.

A measurement system for use in optical metrology, the measurement system which includes a control system configured and operable to carry out the following: (i) receive raw measured data generated by a measurement unit that is configured and operable for performing normal-incidence spectral interferometric measurements on a sample and generating the raw measured data indicative of spectral interferometric signals measured on the sample for a number of different optical path differences (OPDs) between sample and reference arms using infrared wavelengths; (ii) extract, from the raw measured data, a portion of spectral interferometric signals describing variation of signal intensity with a change of an optical path difference OPD during interferometric measurements, said portion of the spectral interferometric signals being independent of interferometric signals returned from a bottom portion of the sample in response to said illuminating electromagnetic field; and (iii) directly determine, from the extracted portion of the spectral interferometric signals, both spectral amplitude and phase of reflection of the illuminating electromagnetic field from the top portion of the sample, thereby enabling to determine a measured spectral signature characterizing the top portion of the sample.

A system and methods for OCD metrology are provided including setting an interferometry mirror of the system at each of multiple positions z, wherein at each position the mirror reflection is Optical-Path-Difference (OPD) matched with reflection from the at least one reflective surface, and measuring interferometer spectra I measured , with the mirror at each of the multiple positions; then fitting the multiple measured interferometer spectra to an equation for I measured , to solve for non-z-dependent parameters of the equation, leaving a z-dependent function of the wave number k, having fully coherent and partially coherent terms; and removing the partially coherent terms of the function to derive a fully coherent field for characterizing the OCD structure.

A method for evaluating a sample, the method includes performing one or more pump probe measurements, wherein a pump probe measurement includes (i) illuminating the sample by a laser pump beam that is modulated by a modulation frequency; (ii) illuminating the sample by a laser probe beam; (iii) detecting radiation resulting from the illumination of the sample; (iv) determining, based on the detected radiation, thermo-reflectance information regarding a sample region located at a depth of the sample; wherein the thermo-reflectance information comprises information about an oscillatory component of a thermal response of the sample measured during the pump probe measurement; and (v) determining a presence of one or more sample abnormalities based on the analysis results.

Systems and methods are provided for measuring properties of a sample such as a semiconductor element by illuminating a polarizing beam splitter (PBS) with spatially separated non-polarized input optical beams such that the PBS polarizes the input optical beams to produce at least two polarized intermediate optical beams having different (e.g., orthogonal) polarization properties. The polarized intermediate optical beams are further directed to illuminate substantially the same area of a sample. Light returned from the illuminated sample area is directed again through the same PBS to form at least two polarized output beams, having different (e.g., orthogonal) polarization properties, where the differently polarized output optical beams are detectable by use of one or more optical detectors. In some embodiments, the sample is simultaneously illuminated by combined intermediate polarized optical beams of different polarization properties and the polarized output optical beams are also simultaneously measured by the optical detector(s).

A method and system are presented for use in measuring characteristic(s) of patterned structures. The method utilizes processing of first and second measured data, wherein the first measured data is indicative of at least one Raman spectrum obtained from a patterned structure under measurements using at least one selected optical measurement scheme each with a predetermined configuration of illuminating and/or collected light conditions corresponding to the characteristic(s) to be measured, and the second measured data comprises at least one spectrum obtained from the patterned structure in Optical Critical Dimension (OCD) measurement session. The processing comprises applying model-based analysis to the at least one Raman spectrum and the at least one OCD spectrum, and determining the characteristic(s) of the patterned structure under measurements.

A method for evaluating a thick transparent layer, the method includes (i) generating information about relationships between measurements of a spectrometer of an interferometer and optical path difference (OPD) values of the interferometer; wherein the generating of the information comprises illuminating the thick transparent layer by the interferometer: (ii) determining one or more thick transparent layer reflection parameters, based on the information about the relationship; and (iii) determining one or more structural properties of the thick transparent layer based on the one or more thick transparent layer reflection parameters.