阅读说明：本技术 散射测量系统及其使用方法 (Scatterometry system and method of use ) 是由 M·R·C·阿特金森 于 2018-05-03 设计创作，主要内容包括：本发明提供了微散射测量系统,其用于由所收集的数据生成角分辨的散射光轮廓。(The present invention provides a micro-scatterometry system for generating an angularly resolved scattered light profile from collected data.)

1. A micro-scatterometry system, comprising, in order:

a light source providing light of at least one wavelength in the range of 400nm to 700 nm;

a focusing element;

a sample holder;

an aperture; and

a first light detector rotatable about an off-center point, wherein when the light source is energized, a light beam from the light source passes through the focusing element and is focused by the focusing element to a spot focused at the off-center point of the first light detector having an area in a range of 1 square micron to 625 square microns, wherein the focused light diverges after the focal point and divergent light passes through the aperture before contacting the first light detector, and wherein the sample holder is translatable in a plane orthogonal to the incident light beam.

2. The micro-scattering measurement system of claim 1, wherein the light source is a laser.

3. The micro-scatterometry system of any of the preceding claims, wherein the focusing element is a lens.

4. The micro-scatterometry system of claim 1 or 2, wherein the focusing element is a spatial light modulator.

5. The micro-scatterometry system of claim 1 or 2, wherein the focusing element is a parabolic mirror.

6. The micro-scattering measurement system of any preceding claim, further comprising an optical chopper positioned between the light source and the focusing element.

7. The micro-scattering measurement system of claim 6, further comprising a beam splitter positioned between the optical chopper and the focusing element to split a portion of the light beam to a second light detector.

8. The micro-scattering measurement system of claim 7, further comprising an expanded beam spatial filter positioned between the light source and the focusing element.

9. The micro-scattering measurement system of any of claims 1-5, further comprising a beam splitter positioned between the light source and the focusing element to split a portion of the light beam to a second light detector.

10. The micro-scattering measurement system of claim 9, further comprising an expanded beam spatial filter positioned between the beam splitter and the focusing element.

11. The micro-scattering measurement system of claim 10, wherein the light beam is comprised of pulsed light.

12. The micro-scattering measurement system of any of claims 1-5, further comprising an expanded beam spatial filter positioned between the light source and the focusing element.

13. The micro-scattering measurement system of claim 12, further comprising an optical chopper positioned between the light source and the expanded beam spatial filter.

14. The micro-scattering measurement system of claim 13, wherein the light beam is comprised of pulsed light.

15. The micro-scattering measurement system of any preceding claim, having a specular direction, wherein the first light detector is rotatable about the eccentric point relative to the specular direction in a range of-90 ° to 90 °.

16. The micro-scattering measurement system of any preceding claim, wherein an optical axis extends from the light source towards the sample holder and is perpendicular to both the lens and the sample holder, and wherein the first light detector is rotatable about the eccentric point in a range of-90 ° to 90 ° relative to the specular direction.

17. A method of micro-scattering measurement, the method comprising:

providing a system, said system comprising in sequence:

a light source;

a focusing element;

a sample that is at least one of transmissive or reflective to at least one light having a wavelength in the range of 400nm to 700 nm;

an aperture; and

a first light detector rotatable about an off-center point,

energizing the light source to provide a beam of light having at least one wavelength in the range of 400nm to 700nm, wherein the beam of light from the light source passes through the focusing element and is focused by the focusing element to a spot on or within the sample having an area in the range of 1 square micron to 625 square microns, wherein the sample holder is translated in a plane orthogonal to the incident beam of light, and wherein at least a portion of the light is transmitted through or reflected by the sample to provide scattered light; and

rotating the first light detector about an off-center point and collecting data generated by the scattered light passing through the aperture onto the first light detector.

18. The method of claim 17, further comprising generating an angle-resolved scattered light profile from the collected data.

19. The method of claim 18, wherein the light source is a laser.

20. The method of any one of claims 17 to 19, wherein the focusing element is a lens.

21. The method of any of claims 17 to 20, wherein the focusing elements are spatial light modulators.

22. The method of any one of claims 17 to 19, wherein the focusing element is a parabolic mirror.

23. The method of any of claims 17 to 22, further comprising an optical chopper positioned between the light source and the focusing element, wherein the method further comprises chopping the light beam with the optical chopper.

24. The method of any of claims 17 to 23, further comprising a beam splitter positioned between the optical chopper and the focusing element to split a portion of the light beam to a second light detector, wherein the method further comprises the beam splitter splitting a portion of the light beam to the second light detector.

25. The method of claim 23, further comprising an expanded-beam spatial filter positioned between the light source and the focusing element, wherein the method further comprises filtering and expanding the light beam with the expanded-beam spatial filter.

26. The method of claim 23, wherein the light beam is comprised of pulsed light.

27. The method of any one of claims 17 to 22, further comprising an expanded-beam spatial filter positioned between the light source and the focusing element, wherein the method further comprises filtering and expanding the light beam with the expanded-beam spatial filter.

28. The system of claim 27, wherein the light beam is comprised of pulsed light.

29. The method of any one of claims 17 to 28, wherein an optical axis extends from the light source towards the sample holder along the incident light beam and is perpendicular to both the lens and the sample holder, and wherein the first light detector is rotatable about the eccentric point in a range of-90 ° to 90 ° relative to the specular direction.

30. The micro-scattering measurement system of any preceding claim 17-28, having a specular direction, wherein the first light detector is rotatable about the eccentric point relative to the specular direction in a range of-90 ° to 90 °.

Background

Various techniques are known in the art for measuring optical properties of a sample that transmits and/or reflects at least one wavelength of light in the range of 400nm to 700 nm.

Scatterometry is a set of techniques in which light scattered away from specular reflection or in the line transmission direction is measured. Scatterometry is used, for example, to measure and monitor the degree of gloss of polished surfaces (e.g., semiconductor wafers and metals). Scatterometry can also be used to measure the functional properties of polymer films (e.g., polymer optical films used in screens on optical devices such as personal devices). Some materials, such as optically clear adhesives, perform better when they scatter a minimal amount of light away from the direction of linear transmission. For materials called light diffusers, it is desirable to have a moderate to high amount of scattering that scatters light with a particular angular distribution.

Current techniques for measuring the intensity of light scattered in a particular direction include those disclosed in astm e430-11 (2011). Such measurements can then be used to define sample haze (i.e., the ratio of light scattered in a particular direction to unscattered light). In this method, the illuminated area of the sample is used on a mm to cm size scale and provides an average of the area scattered in a particular direction.

Other methods known in the art include measuring the distribution of scattered light (i.e., the intensity of scattered light as a function of angle with relatively high (typically, at least 0.2 °) angular accuracy away from the on-line direction). Such methods can be used, for example, to investigate the exact scattered light profile containing more information about the sample, rather than making measurements at several discrete angles (e.g., whether there are oscillations in the scattering profile that indicate a thin layer or diffractive feature on the sample). The total scattered light profile obtained with these methods provides for more in-depth characterization and analysis of the sample. These methods use a collimated beam of light incident on the sample and thus provide a measurement with an optimal lateral resolution of about 1mm (the diameter of the incident collimated beam).

To improve the lateral resolution of scatterometry measurements beyond the two basic methods, a beam of light may be focused onto the sample. However, the light beam reflected from or transmitted through the sample has a natural divergence that must be accounted for. The focused scatterometry method collects light that is either diffusely specular or transmitted on-line, as well as light that is scattered at several discrete angles. Focused scatterometry provides a specific haze value but does not provide a high angular resolution measurement.

Disclosure of Invention

For example, it is desirable for polymer films and materials used in display devices to have both a relatively high angular resolution (typically at least 0.2 °) for determining the exact behavior of light in the system and a relatively high lateral resolution (typically at least 0.1mm) for quantifying the variation in scattering profile across the size scale of the display pixels. A system and method for providing both relatively high angular resolution and relatively high lateral resolution is desired.

In one aspect, the present disclosure describes a micro-scatterometry system, comprising, in order:

a light source providing light at least one wavelength (in some embodiments, at a wavelength of 532 nm) in the range of 400nm to 700nm (in some embodiments, in the range of 442nm to 633 nm);

a focusing element;

a sample holder;

an aperture (e.g., an iris aperture); and

a first light detector rotatable about an off-center point,

wherein when the light source is energized, a light beam from the light source (i.e., at least one light beam) passes through the focusing element and is focused by the focusing element to a spot focused at an off-center point of the first detector having an area in a range of 1 square micron to 625 square microns (in some embodiments, 25 square microns to 225 square microns; in some embodiments, 100 square microns), wherein the focused light diverges after the focal point and the diverging light passes through the aperture before contacting the first light detector, and wherein the sample holder is capable of translating in a plane orthogonal to the incident light beam.

In another aspect, the present disclosure describes a method of micro-scattering measurement, the method comprising:

providing a system comprising, in order:

a light source;

a focusing element;

a sample that is at least one of transmissive or reflective to at least one light having a wavelength in the range of 400nm to 700 nm;

an aperture (e.g., an iris aperture); and

a first light detector rotatable about an off-center point,

energizing a light source to provide a beam of light (i.e., at least one beam of light) having at least one wavelength of light in the range of 400nm to 700nm (in some embodiments, in the range of 442nm to 633 nm), in some embodiments, at a wavelength of 532nm, wherein the beam of light from the light source passes through a focusing element and is focused by the focusing element onto a spot having an area in the range of 1 square micron to 625 square microns (in some embodiments, 25 square microns to 225 square microns; in some embodiments, 100 square microns) on or within a sample, wherein a sample holder translates in a plane orthogonal to the incident beam of light, and wherein at least a portion of the light is transmitted through or reflected by the sample to provide scattered light; and

the first photodetector is rotated about the eccentric point and data generated from scattered light passing through the aperture is collected on the first photodetector.

Embodiments of the micro-scatterometry system and methods of use thereof may advantageously provide, for example, both relatively high angular resolution and relatively high lateral resolution. The method can be used to generate an angle-resolved scattered light profile from the collected data.

Drawings

The figures are schematic illustrations of exemplary devices described herein.

Detailed Description

The micro-scattering measurement systems and methods described herein can be used, for example, to provide analysis of samples such as polymeric materials (e.g., polymeric optical films), ceramics (including glass), metals, semiconductors, and papers. The analysis may be performed on a sample that transmits or reflects at least one light having a wavelength in the range of 400nm to 700 nm.

Referring to the figures, an exemplary micro-scattering measurement system 1100 includes a light source 1101, a focusing element 1103, a sample holder 1105, an aperture 1107, a first light detector 1109 capable of rotating (1106) about an eccentric point 1108. As shown, the micro-scattering measurement system 1100 also includes an optional optical chopper 1111, an optional beam splitter 1113 for use with an optional second photodetector 1112, and an optional beam expanding spatial filter 1114. When the light source 1101 is energized, the light beam 1102 passes through the focusing element 1103 and is focused by the focusing element 1103 to a spot focused at the off-center point 1108 having an area in the range of 1 square micrometer to 625 square micrometers (in some embodiments, 25 square micrometers to 225 square micrometers; in some embodiments, 100 square micrometers). The focused light diverges after the focal point 1104. The diverging light passes through aperture 1107 before contacting first light detector 1109. Sample holder 1105 is capable of translation in a plane orthogonal to incident beam 1102. As shown, sample holder 1105 has sample 1130 mounted therein. Sample 1130 is at least one of transmissive or reflective to at least one light having a wavelength in the range of 400nm to 700 nm. A light beam 1102 from a light source 1101 passes through a focusing element 1103 and is focused by the focusing element 1103 to a spot having an area on or within the sample 1130 in the range of 1 square micron to 625 square microns (in some embodiments, 25 square microns to 225 square microns; in some embodiments, 100 square microns).

During operation on a transmissive sample, the sample holder 1105 translates such that a portion of the sample holder 1105 remains at the eccentric point 1108, and optionally rotates about the eccentric point 1108. During operation with a reflective sample, the sample holder 1105 translates such that a portion of the sample holder 1105 remains at the eccentric point 1108 and rotates about the eccentric point 1108. At least a portion of the light is transmitted through sample 1130 or reflected by sample 1130 to provide scattered light.

During operation, the first light detector 1109 rotates (1106) about the eccentric point 1108 and collects data generated by scattered light passing through the aperture 1107 onto the first light detector 1109. In some embodiments, to analyze the transmitted sample, the optical axis extends along the incident beam from the light source towards the sample holder and is perpendicular to both the lens and the sample holder, and the first photodetector is rotatable about the eccentric point relative to the optical axis in a range of-90 ° to 90 ° (in some embodiments, in a range of-45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °). In some embodiments, for analyzing a reflected sample, there is a specular direction (i.e., a direction equal to an angle between an optical axis extending along the incident beam from the light source toward the sample holder and a direction orthogonal to the sample holder, on an opposite side of the normal to the incident beam of the sample holder, the sample holder lying in a plane defined by the incident beam and the normal to the sample holder), and the first photodetector is rotatable about an off-center point in a range of-90 ° to 90 ° (in some embodiments, -45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °) relative to the specular direction. Generally, the glossier the sample, the narrower the range of rotation of the first photodetector.

The data from the methods described herein can be used to determine a variety of optical properties of the sample, including distinctness of image (DOI), narrow angle haze, wide angle haze, transmission clarity, specular gloss (for reflection) on a micro scale (i.e., less than 1mm (in some embodiments, less than 0.5mm or even less than 0.1 mm)). DOI is a method of characterizing the degree of gloss of a surface by observing the amount of light scattered slightly off the on-line direction (for transmission) or specular direction (for reflection). It can be used to distinguish very glossy materials that will have negligible scattering at large angles, which cannot be distinguished with haze measurement instruments. This change in gloss is important in surface finishes (i.e., polished surfaces) that are intended to be glossy. DOI is light that propagates at 0.3 ° to the mirror (or on-line) and is calculated by: 100 × (1-H)_0.3) In which H is_0.3Is the ratio of the intensity measured at 0.3 DEG to the mirror surface to the intensity measured in the direction of the mirror surface, H_0.3＝I_{Mirror +/-0.3}/I_{Mirror surface}。

The narrow angle haze is light traveling at 2 ° to the specular (or on-line) plane and is calculated by the following formula: 100 XH₂In which H is₂Is the ratio of the intensity measured at 2.0 deg. to the mirror surface to the measured intensity in the direction of the mirror surface. When there is a moderate amount of scattering close to specular (but negligible at high angles), the narrow angle hazeThe degree is used to characterize the sample.

Wide angle haze is used to characterize and distinguish samples that typically have a large amount of scattering, where narrow angle haze and image clarity characteristics would be unusable. Wide angle haze is light that propagates at a specific degree to the specular surface (or on-line) and is calculated by the following formula: 100 XH₅Or 100 XH₁₅In which H is₅And H₁₅Is the ratio of the intensity measured at 5.0 and 15.0, respectively, from the mirror plane to the measured intensity in the direction of the mirror plane, respectively.

The transmission haze is the light scattered at more than 2.5 ° from the collimation direction and is calculated by the following formula: t is_d/T_tX 100 (where T_dDiffusion transmission, T_tTotal transmission).

Transmission clarity is light scattered at less than 2.5 ° from the collimation direction, normalized to the directed beam intensity without the sample in place.

Specular gloss (for reflection) is the specular intensity for 20 ° or 30 ° incidence and detection, and is calculated as R_s,20Or R_s,30(specular intensity measured at 20 ° or 30 °).

Embodiments of the micron scatterometry systems and methods described herein are particularly useful for determining the micro haze of polymeric materials (e.g., polymeric optical films), ceramics (including glass), metals, semiconductors, and papers. For example, polymeric optical films are used in a variety of devices, including small screen devices such as mobile phones, personal display devices (PDAs), and digital cameras. Some of these devices use Organic Light Emitting Diodes (OLEDs) for illumination. The main OLED option currently on the market is the Active Matrix Organic Light Emitting Diode (AMOLED) for such handheld devices. Such handheld devices have a top-emitting architecture and currently do not use any light extraction method other than employing strong microcavities. This strong cavity design can have high light efficiency, but much poorer angular color uniformity than the cavity of a Liquid Crystal Display (LCD).

Typically, the color of the OLED screen shifts greatly as the viewing angle increases away from normal incidence, but the LCD display shifts only slightly. This is a visually significant difference between the two display technologies. How to improve angular color uniformity remains a challenge for AMOLED displays with strong cavity designs. Moderate optical differences can perform this function, and it is helpful that these differences be spatially uniform.

The visual perceived quality of a pixelated display requires a certain uniformity of controlled haze for the spatial distribution of the display pixels on the approximate length scale. Non-uniformity in haze over an approximate length scale of a display pixel can lead to optical defects such as pixel blur or so-called sparkle. Such quality of a sample (e.g., a polymeric optical film) can be measured via a micro-haze uniformity measurement using a micro-scattering measurement system. A micro-scatterometry system and method of using the same are described herein (see "optical Performance test method: micro-haze uniformity" in the examples below). The test method provides measurements from a sampling beam illuminating a sample of tens of microns. In this measurement, the polymer film surface is scanned with an optical probe having a sub-pixel size, while measuring the standard deviation of the measured micro-haze level. The micro-haze measurement technique allows for sample analysis of spatial frequencies corresponding to peaks of human visual perception (i.e., spatial frequencies in the range of 1-5 line pairs per millimeter for typical viewing distances). The micro haze measurement allows for the examination of the dimensional scale variation on the dimensional scale of the display pixel size. In contrast, conventional haze measurement systems analyze large areas of optical film for each measurement and are unable to distinguish differences in visual perception on the critical length scale of a pixelated display.

The components of the apparatus described herein may be prepared by techniques known in the art and/or may be commercially available, for example, from Melles Griot Corporation of calsbard, california (Melles Griot, Carlsbad, CA) or Newport Corporation of europe, california (Newport Corporation, Irvine, CA).

The light source provides light at least one wavelength (in some embodiments, at a wavelength of 532 nm) in the range of 400nm to 700nm (in some embodiments, in the range of 442nm to 633 nm). Exemplary light sources include lasers (including pulsed lasers), Light Emitting Diodes (LEDs), and arc lamps. Typically, the laser light source has a power rating (in some embodiments, 10 milliwatts) for light incident on the sample in a range of 1 milliwatt to 50 milliwatts (in some embodiments, in a range of 1 milliwatt to 25 milliwatts). An exemplary laser is available from Melles Griot corporation as, for example, a model 85-GCB-020, 532nm20mW DPSS laser. Typically, arc lamps have a power rating of about several watts. An exemplary ARC lamp is available, for example, from sorebo optoelectronics, inc (Thorlabs inc., Newton, NJ) of Newton, NJ under the trade designation "SLS 4001 XENON SHORT ARC LIGHT SOURCE" (1.3 watts).

Exemplary focusing elements include lenses (e.g., objective lenses, single lenses, or double lenses), spatial light modulators, and parabolic mirrors. Such focusing elements are known in the art and may be manufactured or commercially available. Exemplary lenses are available, for example, from Newport Corporation (Newport Corporation) (e.g., under the trade designation "PAC 058 ACHROMATIC DOUBLET" (1 inch diameter, 150mm focal length)). Exemplary SPATIAL light modulators are available, for example, from Sorbon electro-optical technology, Inc. (Thorlabs Inc.), under the trade designation "EXULUS SPATIAL LIGHT MODULATOR"; commercially available under the trade designation "LC 2012" from Holoeye Photonics ltd (Holoeye Photonics AG, San Diego, CA). Exemplary PARABOLIC mirrors are available, for example, from Edmund Optics, Barrington, NJ, of Barrington, NJ under the trade designation "12.7 x 6.35mm PFL 90 ° OFF-AXIS parablock gold gildrm"; available from Sorbo photoelectric technology, Inc under the trade designation "MPD 00M9-F0190 ℃ OFF-AXIS PARABOLIC MIRROR".

In some embodiments, the aperture is a variable aperture (available, for example, from Nybolt under the trade designation "COMPACT ADJUSTABLE WIDTH SLIT M-SV-0.5").

The micro-scattering measurement system includes a first light detector that rotates about an eccentric point. In some embodiments, to analyze the transmitted sample, the optical axis extends along the incident beam from the light source towards the sample holder and is perpendicular to both the lens and the sample holder, and the first photodetector is rotatable about the eccentric point relative to the optical axis in a range of-90 ° to 90 ° (in some embodiments, in a range of-45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °). In some embodiments, for analyzing a reflected sample, there is a specular direction (i.e., a direction equal to an angle between an optical axis extending along the incident beam from the light source toward the sample holder and a direction orthogonal to the sample holder, on an opposite side of the normal to the incident beam of the sample holder, the sample holder lying in a plane defined by the incident beam and the normal to the sample holder), and the first photodetector is rotatable about an off-center point in a range of-90 ° to 90 ° (in some embodiments, -45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °) relative to the specular direction. A suitable detector is available, for example, from Nybolt, Inc. under the trade designation "NEW FOCUS LARGE-AREA PHOTO RECEIVER" model 2031.

Optionally, the micro-scattering measurement system comprises an optical chopper. The optical chopper is used with a lock-in amplifier, where the optical chopper modulates the probe beam and, therefore, scatters light, and the lock-in amplifier only measures the signal detected at the chopping frequency. This serves to increase the signal-to-noise ratio of the system by resisting variations in the background light and electronic noise from the detector. Typically, an optical chopper is positioned between the light source and the focusing element. An alternative to using an optical chopper is to use a pulsed light source. In some embodiments, the optical chopper is a mechanical modulator or an acousto-optic modulator. Optical choppers are known in the art and may be manufactured or commercially available. An exemplary OPTICAL CHOPPER is available, for example, from Nipport under the trade designation "NEW FOCUS3501OPTIC CHOPPER". In some embodiments, an optical chopper is positioned between the light source and the expanded beam spatial filter.

Optionally, the micro-scattering measurement system comprises a beam expanding spatial filter positioned between the light source and the focusing element. Typically, lasers do not produce a beam with a smooth, regular intensity profile. These variations, if used as is, can be misinterpreted as features in the scattered light profile. The spatial filter is used to remove irregular behavior in the beam profile, thereby improving the quality of the scattered light profile. In a spatial filter, input light is focused towards a small pinhole, and the pinhole acts as a point source of light transmitted through it. The now diverging light is then collimated with a lens positioned one focal length away from the pinhole. The focal length is typically used so that the diameter of the now collimated beam is larger than the diameter of the beam produced by the laser. The larger beam better fills the focusing lens further along the beam, which produces a smaller focused spot than that produced by the original diameter beam. Exemplary spatial filters and beam expanders are available, for example, from Neybolt under the trade designation "COMPACT FIVE AXIS SPATIAL FILTER MODEL 910A" for use with a collimating lens achromatic doublet (1 inch diameter, 50.8mm focal length) available from Neybolt under the trade designation "PAC 040". In some embodiments, the expanded beam spatial filter is positioned between the beam splitter and the focusing element.

Optionally, the micro-scattering measurement system comprises a second light detector. Such photodetectors are available, for example, from Nybolt, Inc. under the trade designation "NEW FOCUS LARGE-AREA PHOTOREIVEVE" model 2031. The second detector is used to monitor changes in the intensity of the light beam from the light source. In some embodiments, the beam splitter transmits about 90% of the light beam toward the focusing element and reflects about 10% of the light beam toward the second detector. The signal from the first detector is divided by the signal from the second detector to account for the change in intensity of the light beam.

In some embodiments, the second light detector is positioned between the light source and the focusing element. In some embodiments, the second light detector is positioned between the optical chopper and the focusing element.

If a second light detector is used, a beam splitter is used to split a portion of the light beam to the second light detector. Exemplary BEAM splitters are available, for example, from Nippon corporation under the trade designation "UV FUSED SILICA METALLIC NEUTRAL DENSITYFILTER FQR-ND 01" or "BROADBAND BEAM SAMPLER 10B20 NC.1".

Other components of the micro-scatterometry system may be purchased from commercial sources, for example. Such other components include sample mounts (e.g., spring-loaded mounts (available, for example, under the trade designation "M-PPF 50" from newport corporation), sample STAGEs (e.g., linear translation STAGEs (available, for example, under the trade designation "MFA-1C" from newport corporation), detector STAGEs (available, for example, under the trade designation "rota STAGE RV350 PE" from newport corporation), goniometer STAGEs (available, for example, under the trade designation "goniometrictage BGM 160 PE" from newport corporation), STAGE drives (for the sample and detector STAGEs (available, for example, under the trade designation "unisal MOTION CONTROLLER rod 300" from newport corporation)), and detection electronics (available, for example, under the trade designation "ANALOG-TO-DIGITAL CONVERTER 92ni 15, CDAQ 9172 chips" from National Instruments, Austin, texas (National Instruments, Austin).

Exemplary embodiments

1a. a micro-scattering measurement system comprising, in order:

a light source providing light at least one wavelength (in some embodiments, at a wavelength of 532 nm) in the range of 400nm to 700nm (in some embodiments, in the range of 442nm to 633 nm);

a focusing element;

a sample holder;

an aperture (e.g., an iris aperture); and

a first light detector rotatable about an off-center point,

wherein when the light source is energized, a light beam from the light source (i.e., at least one light beam) passes through the focusing element and is focused by the focusing element to a spot focused at an off-center point of the first light detector having an area in a range of 1 square micron to 625 square microns (in some embodiments, 25 square microns to 225 square microns; in some embodiments, 100 square microns), wherein the focused light diverges after the focal point and the diverging light passes through the aperture before contacting the first light detector, and wherein the sample holder is capable of translating in a plane orthogonal to the incident light beam.

The micro-scattering measurement system of exemplary embodiment 1A, wherein the light source is a laser.

The micron scatterometry system of exemplary embodiment 2A, wherein the light source has a power rating (in some embodiments, 10 milliwatts) in a range of 1 milliwatts to 50 milliwatts (in some embodiments, in a range of 1 milliwatts to 25 milliwatts).

The micro-scatterometry system of any of the previous a exemplary embodiments, wherein the focusing element is a lens (e.g., an objective lens, a single lens, or a double lens).

The micro-scatterometry system of any of exemplary embodiments 1A-3A, wherein the focusing element is a spatial light modulator.

The micro-scatterometry system of any of exemplary embodiments 1A-3A, wherein the focusing element is a parabolic mirror.

The micro-scattering measurement system of any of the preceding a exemplary embodiments, further comprising an optical chopper positioned between the light source and the focusing element.

The micro-scattering measurement system of exemplary embodiment 7A, wherein the optical chopper is a mechanical modulator.

The micro-scattering measurement system of exemplary embodiment 7A, wherein the optical chopper is an acousto-optic modulator.

The micro-scattering measurement system of any of exemplary embodiments 7A-9A, further comprising a beam splitter positioned between the optical chopper and the focusing element to split a portion of the light beam to a second light detector.

The micro-scattering measurement system of exemplary embodiment 10A, further comprising an expanded-beam spatial filter positioned between the light source and the focusing element (e.g., between the beam splitter and the focusing element).

12a. the micro-scattering measurement system of any of exemplary embodiments 1A-6A, further comprising a beam splitter positioned between the light source and the focusing element to split a portion of the light beam to a second light detector.

The micro-scattering measurement system of exemplary embodiment 12A, further comprising an expanded beam spatial filter positioned between the beam splitter and the focusing element.

14a. the micro-scattering measurement system of exemplary embodiment 12A or 13A, wherein the light beam is comprised of pulsed light.

The micro-scattering measurement system of any of exemplary embodiments 1A-6A, further comprising an expanded beam spatial filter positioned between the light source and the focusing element.

The micro-scattering measurement system of exemplary embodiment 15A, further comprising an optical chopper positioned between the light source and the expanded beam spatial filter.

The micro-scattering measurement system of exemplary embodiment 16A, wherein the optical chopper is a mechanical modulator.

18a. the micro-scattering measurement system of exemplary embodiment 16A, wherein the optical chopper is an acousto-optic modulator.

The micro-scattering measurement system of exemplary embodiment 15A, wherein the light beam is comprised of pulsed light.

20a. the backscatter measurement system of any one of the preceding a exemplary embodiments, wherein the optical axis extends from the light source (i.e., from a position where light is emitted from the light source when energized) toward the sample holder, and is perpendicular to both the lens and the sample holder, and wherein the first photodetector is rotatable about the eccentric point relative to the optical axis in a range of-90 ° to 90 ° (in some embodiments, in a range of-45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °).

21a. the micro-scatterometry system of any of the preceding a exemplary embodiments, having a specular direction (i.e., a direction equal to an angle between an optical axis extending along the incident beam from the light source towards the sample holder and a direction orthogonal to the sample holder, on an opposite side of the normal to the incident beam of the sample holder, the sample holder lying in a plane defined by the incident beam and the normal to the sample holder), wherein the first photodetector is rotatable about the eccentric point relative to the specular direction in a range of-90 ° to 90 ° (in some embodiments-45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °).

A method of micro-scattering measurement, the method comprising:

providing a system comprising, in order:

a light source;

a focusing element;

a sample that is at least one of transmissive or reflective to at least one light having a wavelength in the range of 400nm to 700 nm;

an aperture (e.g., an iris aperture); and

a first light detector rotatable about an off-center point,

energizing a light source to provide a beam of light (i.e., at least one beam of light) having at least one wavelength in the range of 400nm to 700nm (in some embodiments, in the range of 442nm to 633nm (in some embodiments, at a wavelength of 532 nm)), wherein the beam of light from the light source passes through a focusing element and is focused by the focusing element onto a spot having an area in the range of 1 square micron to 625 square microns (in some embodiments, 25 square microns to 225 square microns; in some embodiments, 100 square microns) on or within a sample, wherein a sample holder translates in a plane orthogonal to the incident beam of light, and wherein at least a portion of the light is transmitted through or reflected by the sample to provide scattered light, and

the first photodetector is rotated about the eccentric point and data generated from scattered light passing through the aperture is collected on the first photodetector.

The method of exemplary embodiment 1B, further comprising generating an angle-resolved scattered light profile from the collected data.

The method of any of the preceding B exemplary embodiments, wherein the light source is a laser.

The method of exemplary embodiment 3B, wherein the light source has a power rating (in some embodiments, 10 milliwatts) in a range of 1 milliwatts to 50 milliwatts (in some embodiments, in a range of 1 milliwatts to 25 milliwatts).

The method of any of the preceding B exemplary embodiments, wherein the focusing element is a lens (e.g., objective lens, single lens, or double lens).

The method of any of exemplary embodiments 1B-4B, wherein the focusing elements are spatial light modulators.

The method according to any one of exemplary embodiments 1B to 4B, wherein the focusing element is a parabolic mirror.

The method of any of the preceding B exemplary embodiments, further comprising an optical chopper positioned between the light source and the focusing element, wherein the method further comprises chopping the light beam with the optical chopper.

The method of example embodiment 8B, wherein the optical chopper is a mechanical modulator.

The method according to exemplary embodiment 8B, wherein the optical chopper is an acousto-optic modulator.

The method of any of exemplary embodiments 1B-7B, further comprising a beam splitter positioned between the optical chopper and the focusing element to split a portion of the light beam to a second light detector, wherein the method further comprises the beam splitter splitting a portion of the light beam to the second light detector.

The method according to exemplary embodiment 11B, further comprising an expanded-beam spatial filter positioned between the light source and the focusing element (e.g., between the beam splitter and the focusing element), wherein the method further comprises filtering and expanding the light beam with the expanded-beam spatial filter.

The method of any of exemplary embodiments 1B-7B, further comprising a beam splitter positioned between the light source and the focusing element to split a portion of the light beam to the second light detector, wherein the method further comprises the beam splitter splitting a portion of the light beam to the second light detector.

The method according to exemplary embodiment 13B, further comprising an expanded beam spatial filter positioned between the beam splitter and the focusing element, wherein the method further comprises filtering and expanding the beam with the expanded beam spatial filter.

15b. the method of exemplary embodiment 13B or 14B, wherein the light beam is comprised of pulsed light.

The method according to any one of exemplary embodiments 1B-7B, further comprising an expanded beam spatial filter positioned between the light source and the focusing element, wherein the method further comprises filtering and expanding the light beam with the expanded beam spatial filter.

The method of exemplary embodiment 16B, further comprising an optical chopper positioned between the light source and the expanded beam spatial filter, wherein the method further comprises chopping the light beam with the optical chopper.

The method of example embodiment 17B, wherein the optical chopper is a mechanical modulator.

The method of example embodiment 17B, wherein the optical chopper is an acousto-optic modulator.

The method of exemplary embodiment 19B, wherein the light beam is comprised of pulsed light.

The method of any of the preceding B exemplary embodiments, wherein the optical axis extends along the incident light beam from the light source towards the sample holder and is perpendicular to both the lens and the sample holder, and wherein the first photodetector is rotatable about the eccentric point relative to the optical axis in a range of-90 ° to 90 ° (in some embodiments, in a range of-45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °).

22b. the method of any of the preceding B example embodiments, having a specular direction (i.e., a direction equal to an angle between an optical axis extending along the incident beam from the light source toward the sample holder and a direction orthogonal to the sample holder, on an opposite side of a normal to the incident beam of the sample holder, the sample holder lying in a plane defined by the incident beam and a normal to the sample holder), wherein the first photodetector is rotatable about an off-center point relative to the specular direction in a range of-90 ° to 90 ° (in some embodiments-45 ° to 45 °, -20 ° to 20 °, -20 ° to 5 °, -10 ° to 10 °, or even-6 ° to 6 °).

Advantages and embodiments of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. All parts and percentages are by weight unless otherwise indicated.