Optical metrology with supercontinuum laser illumination

Abstract

A system and methods of optical metrology and inspection are provided. A supercontinuum laser (SCL) source generates an SCL output that is conditioned by a pulse stretcher to form a spectrally dispersed plane. A spectral balancing filter is positioned in the spectrally dispersed plane to provide a balanced broadband output, which is then temporally dispersed by the pulse stretcher to form a temporally dispersed SCL output. The temporally dispersed SCL output is directed along normal and / or oblique paths toward a sample surface, and reflected radiation from the sample surface is directed to one or more spectrometers for measurement.

Description

OPTICAL METROLOGY WITH SUPERCONTINUUM LASERILLUMINATIONFIELD OF THE INVENTION

[0001] The present invention relates generally to the field of optical inspection, and in particular to spectroscopic metrology.BACKGROUND

[0002] Optical critical dimension (OCD) metrology employs methods of scatterometry to measure scatterometric data, that is, reflected light radiation that is indicative of optical properties of patterns of a sample being measured. A measurement set of scatterometric data may include spectrograms that are measures of reflected radiation intensity over a range of wavelengths or angles.

[0003] Exemplary scatterometric schemes for measuring (acquiring) scatterometry data (e.g., spectrograms) may include spectral ellipsometers (SE), spectral reflectometers (SR), polarized spectral reflectometers, spectral interferometers (SI), as well as other optical critical dimension (OCD) metrology tools. Such tools are incorporated into OCD metrology systems currently available. One such OCD metrology system is the NOVA T600® Advanced OCD Metrology tool, commercially available from Nova Measuring Instruments Ltd. of Rehovot, Israel, which takes measurements of pattern parameters that may be at designated test sites or "in-die." Additional methods for measuring critical dimensions (CDs) include interferometry, X-ray Raman spectrometry (XRS), X-ray diffraction (XRD), and pump-probe tools, among others. Some examples of such tools are disclosed in patents WO2018 / 211505, US Patent 10,161,885, US Patent 10,054,423, US Patent 9,184,102, and US Patent 10,119,925, all assigned to the Applicant and incorporated herein by reference in their entirety.

[0004] A variety of illumination sources are commonly used for scatterometry measurements, including white light and laser sources. Recently, supercontinuum lasers have been described as a possible illumination source. Supercontinuum lasers (SCLs) are lasers that generate a very broad spectrum of light, often spanning ultraviolet through visible to infrared, by optically pumping a nonlinear medium, such as photonic crystal fiberwith a short laser pulse. Different types of SCLs are characterized by their spectral coverage, pulse repetition rate, pulse duration, coherence, and delivery optics.

[0005] Patent US 9,952,140 B2 (“Small Spot Size Spectroscopic Ellipsometer”) describes metrology systems in which a broadband illumination source, which may include a supercontinuum laser, is directed through an objective having reflective optical elements to minimize dispersion. The system incorporates an aperture assembly that can be dynamically adjusted to define incident angles and azimuthal ranges, and the illumination is directed onto a measurement target at small angles of incidence. Radiation reflected from the target is then directed through polarization optics and dispersed by spectrometers to generate spectral measurement data.

[0006] Patent US 11,675,208 Bl (“Reflectometer, Spectrophotometer, Ellipsometer and Polarimeter System with a Supercontinuum Laser Source and Improved Detector System”) describes the use of a supercontinuum laser as a broadband source in combination with multiple detection assemblies. The system includes beam delivery optics to shape the broadband output, polarization elements to prepare incident states, and spectrometer arrays to detect reflected or transmitted radiation over a broad spectral range. The detectors are coupled to processing electronics that record intensity as a function of wavelength.

[0007] The present invention provides solutions to remaining challenges associated with the use of supercontinuum lasers in optical metrology, including issues related to spectral stability, spectral balance, and the risk of wafer damage.SUMMARY

[0008] The present invention provides an optical metrology system and corresponding methods for inspection of wafers using a supercontinuum laser (SCL) illumination source in combination with optical conditioning and measurement modules. An SCL source generates an output that is received by a pulse stretcher to form a spectrally dispersed plane. A spectral balancing filter positioned in this plane produces a balanced broadband output, which is then temporally dispersed by the pulse stretcher to provide a temporally dispersed SCL output. The temporally dispersed SCL output is directed toward a sample surface by an optical inspection module, and reflected radiation is collected along normal incidence and oblique incidence paths to produce measurement results.

[0009] In one aspect, a monitor spectrometer samples a portion of the SCL output in parallel with measurement. The monitor spectrometer determines spectral characteristics of the illumination and provides calibration data used to normalize the measurement results, thereby compensating for pulse-to-pulse spectral fluctuations of the SCL.

[0010] In another aspect, a wavefront shaping filter is positioned in the normal incidence path to condition the temporally dispersed output before reaching the sample. In the oblique incidence path, a broadband half-wave plate (HWP) may be employed to rotate the polarization, enabling ellipsometric measurements. Polarization control may be employed for both illumination and collection, including polarizers and retarders to enable full polarimetric measurements. Both reflectometry and ellipsometry data may be acquired, synchronized to the triggering of the SCL and spectrometers by a control unit.

[0011] The combination of these features provides several advantages. The pulse stretcher and spectral balancing filter together deliver a broadband, temporally dispersed illumination with uniform spectral distribution, enabling high-quality measurement across a wide wavelength range. The monitor spectrometer continuously calibrates measurement data to eliminate errors caused by spectral imbalance and source fluctuations. Parallel analysis of p- and s-polarized components allows ellipsometry to be performed during continuous stage motion, maintaining throughput without requiring stop-and-go measurements. The coordinated triggering of source, stage, and spectrometers ensures precise alignment of measurements with sample position. Collectively, these innovations enable stable, broadband optical metrology and inspection with improved accuracy and speed using a supercontinuum laser source.BRIEF DESCRIPTION OF DRAWINGS

[0012] For a better understanding of various embodiments of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings. Structural details of the invention are shown to provide a fundamental understanding of the invention, the description, taken with the drawings, making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

[0013] In the accompanying drawings:

[0014] Fig. 1 is a schematic diagram of a spectroscopic measurement system for metrology, including a supercontinuum laser (SCL), according to embodiments of the present invention;

[0015] Fig. 2 is a schematic diagram of a pulse stretcher filter of the spectroscopic measurement configured to generate a balanced, temporally dispersed SCL output, including a supercontinuum laser (SCL), according to embodiments of the present invention;

[0016] Fig. 3 is a flow diagram of steps performed in the operation of a spectroscopic measurement including generation of a balanced, temporally dispersed SCL output, according to embodiments of the present invention.DETAILED DESCRIPTION

[0017] For a better understanding of the system and methods, reference is now made to Figs. 1-3, which illustrate representative embodiments of the invention. Taken together, these figures demonstrate how the system architecture, optical conditioning, and coordinated process control work in combination to enable stable, accurate, and high- throughput optical metrology.

[0018] Fig. 1 illustrates an optical metrology system 10 for inspection of a sample 20 (e.g., a semiconductor wafer) mounted on a sample stage 22, according to embodiments of the present invention. A supercontinuum laser (SCL) source 30 generates an SCL output that is delivered to a pulse stretcher 32. The pulse stretcher 32 spatially disperses the broadband spectrum of the SCL output and directs it through a spectral balancing filter, which equalizes spectral intensity across the bandwidth. The stretcher then temporally disperses the balanced output to form a temporally dispersed SCL output. This conditioning provides broadband illumination with reduced spectral nonuniformity, lowered peak pulse power, and stabilized optical acquisition.

[0019] The temporally dispersed SCL output may then be directed along multiple paths before incidence on the sample. In a normal-incidence path, the output may pass through a wavefront-shaping filter that adjusts the spatial amplitude and phase distribution of the illumination to establish a controlled pupil function, reduce aberration, and stabilizereflectometry measurements. In an oblique-incidence path, the output may be directed through a broadband half-wave plate, which rotates the polarization state for subsequent ellipsometry and polarimetry measurements. The use of such a half-wave plate is facilitated by the fact that the SCL output is inherently linearly polarized, unlike lamp-based light sources that require separate polarizers to establish a defined polarization state.

[0020] The conditioned SCL output is routed to the sample 20, which is moved by the stage in synchrony with illumination and data acquisition under the control of a synchronizing control unit 40. The control unit coordinates triggering of the SCL source 30, acquisition by spectrometers 100 and 110, and sample stage positioning. This synchronization enables continuous stage motion during measurement, eliminating settling delays and thereby increasing throughput. The high repetition rate of the SCL source permits triggered data acquisition with precise spatial resolution during scanning, further improving measurement speed and accuracy. In particular, triggering of the SCL output and spectrometer acquisition can be coordinated with sample motion so that sampling occurs at defined spatial positions, enabling spatially resolved measurement without interruption of sample scanning. The triggered nature of the acquisition also supports integration with interferometric or holographic measurement modes, where precise synchronization of stage position and optical phase is desirable.

[0021] Reflected radiation may be collected from any or all of multiple angles of incidence, including the normal path direction, one or more oblique directions, or combinations thereof. In the normal -incidence path, reflected radiation is directed to spectrometer 100, which produces broadband reflectometry results that may be used, for example, to indicate film thickness and structural properties. In the oblique-incidence path, reflected radiation may be separated into p- and s-polarized components by a polarizing control and separation module 60 and directed to spectrometer 110, which produces ellipsometry results as a function of wavelength.

[0022] A monitor spectrometer 120 may be arranged to receive a tapped portion of the SCL output and records its spectral characteristics. These measurements provide calibration data to normalize the reflectometry and ellipsometry results, compensating for pulse-to- pulse fluctuations of the SCL source. In practice, because nonlinear SCL generation processes can introduce noise and instability, the monitor spectrometer allows real-time calibration of measurement results to ensure that spectral variations of the source do notpropagate into sample data.

[0023] The system benefits from the unique properties of the SCL, including its high brightness, which provides very short exposure times and high signal -to-noise ratio, enabling fast data capture and supporting continuous stage scanning. Because of this brightness, exposure times may be reduced to such an extent that data acquisition can continue seamlessly during sample motion, with only data captured at valid sample positions retained for analysis. This continuous scanning reduces sensitivity to unintended mechanical vibrations and eliminates the need for stop-and-settle delays. The spatial coherence of the SCL output allows diffraction-limited focusing on small targets without loss of optical power, avoiding the power losses that occur in lamp-based systems where apertures must be restricted to achieve resolution. Spatial coherence also supports holographic or interferometric methods. The inherent linear polarization of the SCL simplifies polarization manipulation for ellipsometry, allowing the half-wave plate in the oblique incidence path to directly rotate polarization across a broad spectral band. Temporal dispersion applied by the pulse stretcher reduces peak power to avoid damage to the sample or optics while preserving spectral content, addressing the fact that the native SCL is seeded by ultrashort femtosecond or picosecond pulses with high peak intensity. By integrating these features, the system provides stable broadband illumination, enabling accurate and high-throughput optical metrology and inspection that combines reflectometry, ellipsometry, and other spectroscopic techniques.

[0024] Fig. 2 illustrates in greater detail the pulse stretcher filter 32 configured to condition SCL output 200 of the supercontinuum laser (SCL) source 30 to create a temporally dispersed SCL output 210, according to embodiments of the present invention. The SCL output 200 is received at the pulse stretcher 32, which spatially disperses the broadband pulse into its constituent spectral components to form a spectrally dispersed plane 212. In this plane, a spectral balancing filter 220 is positioned so as to selectively attenuate or transmit different spectral portions, thereby producing a balanced broadband output 222. The pulse stretcher 32 further temporally disperses the spectrally balanced output to create the temporally dispersed SCL output 210.

[0025] The pulse stretcher 32 may typically employ a grating-based or prism-based optical configuration that separates spectral components spatially by wavelength. Each wavelength travels along a slightly different optical path, producing an output in which thepulse is temporally elongated, or chirped. This elongation reduces the instantaneous peak power of the ultrashort pulse while retaining its broad spectral coverage, thereby protecting the sample surface and downstream optical components from potential damage and reducing nonlinear distortions. By lowering peak power, the pulse stretcher also stabilizes the acquisition process, minimizing sensitivity to nonlinearities in the optical path. The stretching process is particularly useful because the native SCL pulses originate from femtosecond or picosecond seed lasers with inherently high peak powers, which, if not reduced, could risk sample damage or distortion of metrology results.

[0026] The spectral balancing filter 220 may be implemented as a spatially patterned neutral density filter, a variable optical transmission element, or another spatially selective filtering device positioned at the spectrally dispersed plane 212. Because the SCL output arises from nonlinear optical processes, its spectral distribution is often uneven, with some spectral bands much stronger than others. The spectral balancing filter 220 balances the relative power across a broadband spectrum, generating the balanced broadband output 222. The more uniform distribution improves the accuracy of reflectometry and ellipsometry measurements by preventing certain wavelengths from dominating and enabling subtle wavelength-dependent features of the sample to be detected. For example, the spectral balancing filter 220 typically boosts the relative presence of ultraviolet (UV) light in the balanced broadband output 222. UV light is often particularly useful for identifying certain sample features, but is typically only a small portion of the output of the SCL source.

[0027] The temporally dispersed, spectrally balanced SCL output 210 thus provides broadband illumination that is bright, spatially coherent, and spectrally uniform. The system may take advantage of these properties in several ways. High brightness allows measurements with very short exposure times, which in turn supports continuous data collection during sample stage motion, eliminating stop-and-settle delays. The spatial coherence enables diffraction-limited focusing onto very small targets without loss of optical power, thereby improving resolution for small features and supporting holographic or interferometric techniques. The inherent linear polarization of the SCL output can be rotated by subsequent polarization optics such as a broadband half-wave plate, supporting polarization-resolved metrology including ellipsometry and polarimetry.

[0028] Accordingly, the pulse stretcher filter 32 serves as a critical conditioningmodule that converts the raw SCL output 200 into the temporally dispersed and spectrally balanced SCL output 210. By reducing peak power, equalizing spectral intensity, and preserving high brightness, the pulse stretcher filter 32 provides an illumination source ideally suited to high-throughput optical metrology and inspection.

[0029] Fig. 3 is a flow diagram of steps performed in the operation of a spectroscopic measurement including generation of a balanced, temporally dispersed SCL output, according to embodiments of the present invention. The process begins at step 302, where motion of the stage 20 is initiated according to a predetermined measurement map. The ability to operate the stage in continuous motion is enabled by the short exposure times achievable with high-brightness SCL illumination, which eliminates the need to stop the stage for each measurement. Continuous scanning supports higher throughput and reduces sensitivity to mechanical vibrations, and only data acquired at valid sample positions is retained.

[0030] At a step 304, the SCL source 30 is triggered to generate pulsed broadband output in synchrony with the stage motion and in accordance with a measurement sequence defined by the control unit 40. The high repetition rate of the SCL permits triggered data acquisition with defined spatial resolution, ensuring that optical measurements are tightly correlated with sample position during scanning. This coordination of triggering, motion, and acquisition ensures that measurements correspond precisely to sample locations without interruption of the continuous scan.

[0031] At a step 306, the SCL output is conditioned by the pulse stretcher 32 and the spectral balancing filter 220 to generate a temporally dispersed, spectrally balanced broadband output. The pulse stretcher extends the pulse duration, reducing peak power while maintaining spectral content, which prevents sample damage and avoids damage to detectors or other downstream optics. At the same time, the spectral balancing filter 220 equalizes the intensity profile across the spectral range, mitigating the natural imbalance of the SCL spectrum and ensuring uniform spectral power distribution.

[0032] At a step 308, the temporally dispersed output may optionally be directed through a wavefront- shaping filter located in a normal-incidence path. This filter adjusts the spatial amplitude or phase profile of the illumination to establish a controlled pupil function, correct aberrations, and provide a symmetric illumination spot at the samplesurface, thereby stabilizing reflectometry measurements.

[0033] At a step 310, the temporally dispersed output may alternatively or additionally be directed through a broadband half-wave plate in an oblique-incidence path. The halfwave plate rotates the polarization state of the broadband output, which enables polarization-resolved measurements such as ellipsometry or polarimetry.

[0034] At a step 312, measurement results are produced from reflected radiation collected in the normal-incidence path, yielding broadband reflectometry data sensitive to film thickness and structural properties of the sample. At step 314, reflected radiation collected in the oblique-incidence path is separated into p-polarized and s-polarized components by the polarizing control and separation module 60, and analyzed by spectrometer 110 to produce ellipsometry results as a function of wavelength. Measurements may be taken from any or all of multiple angles of incidence, including the normal path direction, one or more oblique directions, or combinations thereof, depending on the application and required measurement sensitivity.

[0035] At a step 316, the measurement results may be calibrated against the output of the monitor spectrometer 120, which may be adapted to continuously sample and analyze a portion of the SCL output. Because the SCL spectrum may fluctuate from pulse to pulse due to the nonlinear processes that generate it, calibration ensures that measurement data reflect true sample properties rather than source variations. The calibration itself can be performed pulse to pulse or with any other timing period in parallel with the SCL measurement.

[0036] The flow sequence illustrated in Fig. 3 demonstrates how synchronized control of sample motion, pulsed illumination, and spectrometer acquisition, together with temporal dispersion, spectral balancing, and polarization conditioning of the radiation, enable stable and accurate broadband optical metrology. By leveraging the high brightness, high repetition rate, spatial coherence, spectral balancing, and inherent polarization of the SCL, the system achieves fast and precise measurements across a wide spectral range while maintaining throughput required in semiconductor manufacturing environments.

[0037] With respect to the flow chart described above, it is to be understood that blocks may be implemented in a different order than shown, including concurrent or reversed execution, and may also be realized by special purpose hardware or by a combination ofhardware and instructions. It also is to be understood that embodiments of the invention may include a system, a method, and / or a computer program product. A computer program product may include a computer readable storage medium having instructions stored thereon for causing the control unit, or other processing elements, to carry out aspects of the invention. Moreover, any reference to a method should be applied mutatis mutandis to a system capable of executing the method and / or should be applied mutatis mutandis to a non-transitory computer readable medium that stores instructions for implanting the method. Similarly, any reference to a system should be applied mutatis mutandis to a method that may be executed by the system and / or should be applied mutatis mutandis to a non-transitory computer readable medium executable by the system, and any reference to a non-transitory computer readable medium should be applied mutatis mutandis to a method implemented by executing instructions stored in the non-transitory computer readable medium and / or should be applied mutatis mutandis to a system capable to execute the instructions.

[0038] Because embodiments of the present invention may be implemented using electronic components and circuits known to those skilled in the art, details have not been explained in any greater extent than that considered necessary for an understanding and appreciation of the underlying concepts of the present invention and in order not to obfuscate or distract from the teachings of the present invention.

[0039] It is to be understood that the processing elements described herein may include the control unit as well as other processing elements operating in common. The processing elements may include one or more processors, memory, I / O devices, and a network interface, and may execute instructions stored in non-transitory computer readable memory in order to carry out aspects of the invention.

[0040] The memory of the control unit, or of other processing elements, may include RAM, ROM, fixed memory (e.g., hard drive), removable memory, or other forms of nontransient, computer readable storage medium capable of retaining instructions for execution. Instructions stored in memory of the processing elements, may include assembler code, ISA instructions, machine instructions, microcode, firmware, state-setting data, or source / object code in one or more languages. Execution may occur entirely within a local device, partly local and partly remote, or entirely remote via a LAN, WAN, or the Internet. In some embodiments, programmable logic such as FPGAs or PLAs may executethe instructions by configuring circuitry to perform aspects of the invention.

[0041] The foregoing descriptions are provided for illustration and are not limiting. Variations and modifications may be made without departing from the scope of the embodiments. Terminology has been selected to explain the principles, technical improvements, and practical applications, and to enable those skilled in the art to practice the invention.

[0042] Examples of the Invention

[0043] An example 1 of the present invention is a system for sample inspection, including a supercontinuum laser (SCL) source configured to generate an SCL output, a pulse stretcher arranged to receive the SCL output and to generate a spectrally dispersed plane, a spectral balancing filter positioned in the spectrally dispersed plane of the pulse stretcher and configured to provide a balanced broadband output. The pulse stretcher is further configured to temporally disperse the balanced broadband output to provide a temporally dispersed SCL output. An optical inspection module is arranged to receive the temporally dispersed SCL output, to direct the temporally dispersed SCL output toward a sample surface, to collect radiation reflected from the sample surface at one or more spectrometers, and responsively to produce spectrometer measurement results.

[0044] An example 2 of the present invention includes the features of example 1 and further comprises a monitor spectrometer arranged to receive a portion of the SCL output, the monitor spectrometer being configured to measure spectral characteristics of the SCL output and to provide calibration data by which measurement results produced by the optical inspection module are corrected.

[0045] An example 3 of the present invention includes the features of either of examples 1 or 2 and further comprises a control unit configured to synchronize triggering of the SCL source (to generate the SCL output) with collection of the reflected radiation by the one or more spectrometers, and with positioning of the sample surface by a sample stage, in accordance with a predefined measurement sequence.

[0046] An example 4 of the present invention includes the features of any one of examples 1-3, wherein the SCL source is adapted to generate the SCL output while the sample stage is in motion.

[0047] An example 5 of the present invention includes the features of any one ofexamples 1-4 and further comprises a wavefront shaping filter arranged in a normal incidence path of the optical inspection module, the wavefront shaping filter being configured to filter the temporally dispersed SCL output before incidence on the sample surface.

[0048] An example 6 of the present invention includes the features of any one of examples 1-5 and further comprises a broadband half-wave plate arranged in an oblique incidence path, the broadband half-wave plate being configured to rotate a polarization of the temporally dispersed SCL output before incidence on the sample surface.

[0049] An example 7 of the present invention includes the features of any one of examples 1-6, wherein the optical inspection module is further configured to separate the reflected radiation collected in the oblique incidence path into p-polarized and s-polarized components, and to produce the measurement results based on amplitude and phase differences between the p-polarized and s-polarized components as a function of wavelength.

[0050] An example 8 of the present invention is a method of sample inspection that includes generating an SCL output from a supercontinuum laser source. The method further includes receiving the SCL output at a pulse stretcher, forming a spectrally dispersed plane in the pulse stretcher, filtering the spectrally dispersed plane with a spectral balancing filter, to provide a balanced broadband output, and temporally dispersing the balanced broadband output with the pulse stretcher to provide a temporally dispersed SCL output. The temporally dispersed SCL output is then directed toward a sample surface. Reflected radiation is then collected at one or more spectrometers that responsively produce spectrometer measurement results.

[0051] An example 9 of the present invention includes the features of example 8 and further comprises monitoring a portion of the SCL output with a monitor spectrometer, and calibrating the measurement results according to spectral characteristics measured by the monitor spectrometer.

[0052] An example 10 of the present invention includes the features of either of examples 8 or 9 and further comprises coordinating, by a control unit, triggering of the SCL source with collecting of the reflected radiation by the one or more spectrometers, and with positioning of the sample surface by a sample stage, in accordance with a predefinedmeasurement sequence.

[0053] An example 11 of the present invention includes the features of any one of examples 8-10 and further comprises triggering the SCL source to generate the SCL output while the sample stage is in motion.

[0054] An example 12 of the present invention includes the features of any one of examples 8-11 and further comprises filtering the temporally dispersed SCL output in the normal incidence path with a wavefront shaping filter before incidence on the sample surface.

[0055] An example 13 of the present invention includes the features of any one of examples 8-12 and further comprises applying a broadband half-wave plate in an oblique incidence path to rotate a polarization of the temporally dispersed SCL output before incidence on the sample surface.

[0056] An example 14 of the present invention includes the features of any one of examples 8-13 and further comprises separating the reflected radiation collected in the oblique incidence path into p-polarized and s-polarized components, and producing polarization measurement results based on amplitude and phase differences between the p- polarized and s-polarized components as a function of wavelength.

Claims

CLAIMS1. An optical metrology system for sample inspection, comprising: a supercontinuum laser (SCL) source configured to generate an SCL output; a pulse stretcher arranged to receive the SCL output and to generate a spectrally dispersed plane; a spectral balancing filter positioned in the spectrally dispersed plane of the pulse stretcher and configured to provide a balanced broadband output, wherein the pulse stretcher is further configured to temporally disperse the balanced broadband output to provide a temporally dispersed SCL output; and an optical inspection module arranged to receive the temporally dispersed SCL output, to direct the temporally dispersed SCL output toward a sample surface, to collect radiation reflected from the sample surface at one or more spectrometers and responsively to produce spectrometer measurement results.

2. The system of claim 1, further comprising a monitor spectrometer arranged to receive a portion of the SCL output, the monitor spectrometer being configured to measure spectral characteristics of the SCL output and to provide calibration data by which measurement results produced by the optical inspection module are corrected.

3. The system of claim 1, further comprising a control unit configured to synchronize triggering of the SCL source, to generate the SCL output, with collection of the reflected radiation by the one or more spectrometers, and with positioning of the sample surface by a sample stage, in accordance with a predefined measurement sequence.

4. The system of claim 3, wherein the SCL source is adapted to generate the SCL output while the sample stage is in motion.

5. The system of claim 1, further comprising a wavefront shaping filter arranged in a normal incidence path of the optical inspection module, the wavefront shaping filter being configured to filter the temporally dispersed SCL output before incidence on the sample surface.

6. The system of claim 1, further comprising a broadband half-wave plate arranged in an oblique incidence path, the broadband half-wave plate being configured to rotate apolarization of the temporally dispersed SCL output before incidence on the sample surface.

7. The system of claim 6, wherein the optical inspection module is further configured to separate the reflected radiation collected in the oblique incidence path into p-polarized and s-polarized components, and to produce the measurement results based on amplitude and phase differences between the p-polarized and s-polarized components as a function of wavelength.

8. A method of sample inspection, comprising: generating an SCL output from a supercontinuum laser source; receiving the SCL output at a pulse stretcher; forming a spectrally dispersed plane in the pulse stretcher and filtering the spectrally dispersed plane with a spectral balancing filter to provide a balanced broadband output; temporally dispersing the balanced broadband output with the pulse stretcher to provide a temporally dispersed SCL output; directing the temporally dispersed SCL output toward a sample surface; and collecting reflected radiation at one or more spectrometers and responsively producing spectrometer measurement results.

9. The method of claim 8, further comprising monitoring a portion of the SCL output with a monitor spectrometer, and calibrating the measurement results according to spectral characteristics measured by the monitor spectrometer.

10. The method of claim 8, further comprising coordinating, by a control unit, triggering of the SCL source with collecting of the reflected radiation by the one or more spectrometers, and with positioning of the sample surface by a sample stage, in accordance with a predefined measurement sequence.

11. The method of claim 10, further comprising triggering the SCL source to generate the SCL output while the sample stage is in motion.

12. The method of claim 8, further comprising filtering the temporally dispersed SCL output in the normal incidence path with a wavefront shaping filter before incidence on the sample surface.

13. The method of claim 8, further comprising applying a broadband half-wave plate in an oblique incidence path to rotate a polarization of the temporally dispersed SCL output before incidence on the sample surface.

14. The method of claim 13, further comprising separating the reflected radiation collected in the oblique incidence path into p-polarized and s-polarized components, and producing polarization measurement results based on amplitude and phase differences between the p- polarized and s-polarized components as a function of wavelength.

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