Title:
SURFACE FEATURES MAPPING
Kind Code:
A1


Abstract:
Provided herein is an apparatus, including a light source configured to illuminate a surface of an article. In addition, the apparatus includes a light detector array. The light detector array includes a number of light sensors configured to simultaneously receive scattered light from features about the entire surface. The light detector array is configured to provide information for qualitatively and quantitatively characterizing the features.



Inventors:
Ahner, Joachim W. (Livermore, CA, US)
Mclaurin, Keith S. (Sunnyvale, CA, US)
Application Number:
15/245049
Publication Date:
12/15/2016
Filing Date:
08/23/2016
Assignee:
Seagate Technology LLC (Cupertino, CA, US)
Primary Class:
International Classes:
G01N21/94; G01N21/88; G01N21/95
View Patent Images:



Primary Examiner:
AKANBI, ISIAKA O
Attorney, Agent or Firm:
DM legacy (Cupertino, CA, US)
Claims:
What is claimed is:

1. An apparatus, comprising: a light source configured to illuminate an entire surface of an article; and a light detector array comprising a plurality of light sensors configured to simultaneously receive scattered light from features about the entire surface, wherein the light detector array is configured to provide information for qualitatively and quantitatively characterizing the features.

2. The apparatus of claim 1, wherein the apparatus is configured to hold the article in a stationary position while the light source illuminates the surface of the article.

3. The apparatus of claim 1, wherein the light source is configured to uniformly illuminate the entire surface of the article.

4. The apparatus of claim 1, wherein the light source is configured to prevent vibrations while the light source illuminates the surface of the article and the light detector array receives the scattered light.

5. The apparatus of claim 1, wherein the features are 50 nm to 0.1 nm in their smallest dimension.

6. The apparatus of claim 1, further comprising a telecentric lens coupled to the light detector array.

7. The apparatus of claim 6, wherein the telecentric lens is configured to prevent feature-position errors in a surface map corresponding to the surface of the article, and the surface map has at least a 10-μm feature-position accuracy.

8. The apparatus of claim 1, wherein each light sensor of the plurality of light sensors corresponds to a pixel in a surface map corresponding to the surface of the article.

9. An apparatus, comprising: a light source configured to homogenously illuminate an entire surface of an article; and a light detector array comprising a plurality of sensors coupled to a double telecentric lens, wherein the light detector array is configured to simultaneously receive light from features about the entire surface of the article, and further configured to provide information for mapping the features.

10. The apparatus of claim 9, wherein the apparatus is configured to hold the article in a stationary position without rotation while the light source uniformly illuminates the entire surface of the article.

11. The apparatus of claim 10, wherein the light source is configured to minimize vibrations while the light source illuminates the surface of the article and the light detector array receives the light.

12. The apparatus of claim 9, wherein each of the plurality of sensors are between 1 μm and 10 μm in their smallest dimension.

13. The apparatus of claim 12, wherein the plurality of sensors are configured to detect features that are more than 100 times smaller than one of the plurality of sensors.

14. An apparatus, comprising: a light source configured to illuminate an entire surface of an article, wherein light incident upon the surface includes infrared wavelengths; and a light detector array comprising a plurality of light sensors configured to simultaneously receive light from features about the entire surface, wherein the light detector array is configured to provide information for analyzing the light received from the features.

15. The apparatus of claim 14, wherein the apparatus is configured to hold the article in a stationary position without rotation while the light source uniformly illuminates the entire surface of the article.

16. The apparatus of claim 14, wherein the light source is a high-speed flash lamp configured to prevent vibrations while the light source uniformly illuminates the entire surface of the article.

17. The apparatus of claim 14, wherein the light source is configured to prevent feature-position errors in a surface map.

18. The apparatus of claim 14, wherein each of the plurality of light sensors is micrometer sized and corresponds to a pixel in a surface map.

19. The apparatus of claim 14, wherein the light detector array is further configured to provide information for quantitatively characterizing the features.

20. The apparatus of claim 14, wherein the light detector array is further configured to provide information for qualitatively characterizing the features.

Description:

CROSS REFERENCE

This application is a continuation of prior U.S. patent application Ser. No. 14/685,899, filed Apr. 14, 2015, which is a continuation of prior U.S. patent application Ser. No. 13/890,470, filed May 9, 2013, now U.S. Pat. No. 9,036,142, which claims the benefit of U.S. Provisional Patent Application No. 61/644,998, filed May 9, 2012.

BACKGROUND

An article fabricated on a production line may be inspected for certain features, including defects that might degrade the performance of the article or a system comprising the article. For example, a hard disk for a hard disk drive may be fabricated on a production line and inspected for certain surface features, including surface and subsurface defects that might degrade the performance of the disk or the hard disk drive. Accordingly, apparatuses and methods operable to inspect articles for features such as defects are merited.

SUMMARY

Provided herein is an apparatus, including a light source configured to illuminate a surface of an article. In addition, the apparatus includes a light detector array. The light detector array includes a number of light sensors configured to simultaneously receive scattered light from features about the entire surface. The light detector array is configured to provide information for qualitatively and quantitatively characterizing the features.

These and other features and aspects of the invention may be better understood with reference to the following drawings, description, and appended claims.

DRAWINGS

FIG. 1 provides a schematic illustrating detection of surface features of articles in accordance with an embodiment.

FIG. 2 provides a schematic illustrating photon scattering from a surface feature of an article in accordance with an embodiment.

FIG. 3 provides a schematic illustrating photons scattering from a surface feature of an article, through an optical component, and onto a photon detector array in accordance with an embodiment.

FIG. 4 provides an image of a map of surface features of an article in accordance with an embodiment.

FIG. 5 provides a close-up image of the map of surface features provided in FIG. 4.

FIG. 6A (top) provides a close-up image of a surface feature from the map provided in FIG. 5, and FIG. 6A (bottom) provides photon scattering intensity distribution of the surface feature.

FIG. 6B (top) provides a pixel-interpolated image of the surface feature from FIG. 6A, and FIG. 6B (bottom) provides a pixel-interpolated photon scattering intensity distribution of the surface feature.

DESCRIPTION

Before embodiments of the invention are described in greater detail, it should be understood by persons having ordinary skill in the art to which the invention pertains that the invention is not limited to the particular embodiments described and/or illustrated herein, as elements in such embodiments may vary. It should likewise be understood that a particular embodiment described and/or illustrated herein has elements which may be readily separated from the particular embodiment and optionally combined with any of several other embodiments or substituted for elements in any of several other embodiments described herein.

It should also be understood by persons having ordinary skill in the art to which the invention pertains that the terminology used herein is for the purpose of describing particular embodiments of the invention, and the terminology is not intended to be limiting. Unless indicated otherwise, ordinal numbers (e.g., first, second, third, etc.) are used to distinguish or identify different elements or steps in a group of elements or steps, and do not supply a serial or numerical limitation on the elements or steps of the claimed invention or particular embodiments of the invention. For example, “first,” “second,” and “third” elements or steps need not necessarily appear in that order, and the claimed invention, or particular embodiments of the invention, need not necessarily be limited to three elements or steps. It should also be understood that, unless indicated otherwise, any labels such as “left,” “right,” “front,” “back,” “top,” “bottom,” “forward,” “reverse,” “clockwise,” “counter clockwise,” “up,” “down,” or other similar terms such as “upper,” “lower,” “aft,” “fore,” “vertical,” “horizontal,” “proximal,” “distal,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. It should also be understood that the singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by persons of ordinary skill in the art to which the invention pertains.

An article fabricated on a production line may be inspected for certain features, including defects that might degrade the performance of the article or a system comprising the article. For example, a hard disk for a hard disk drive may be fabricated on a production line and inspected for certain surface features, including surface and subsurface defects that might degrade the performance of the disk or the hard disk drive. Provided herein are apparatuses and methods for inspecting articles to detect and/or map certain surface features such as surface and/or subsurface defects. Embodiments of the invention will now be described in greater detail.

With respect to articles that may be inspected with apparatuses and methods herein, such articles include any article of manufacture or a workpiece thereof in any stage of manufacture having one or more optically smooth surfaces, examples of which include, but are not limited to, semiconductor wafers, magnetic recording media (e.g., hard disks for hard disk drives), and workpieces thereof in any stage of manufacture. Such articles may be inspected for certain features, including surface and/or subsurface defects that might degrade the performance of the article, which surface and/or subsurface defects include particle and stain contamination, as well as defects including scratches and voids. With respect to particle contamination, for example, particles trapped on a surface of an intermediate hard disk (i.e., workpiece) for a hard disk drive may damage subsequently sputtered films. Particle contamination may also contaminate a finished surface of a hard disk drive, leading to scratch formation, debris generation, and corruption of the spacing between the hard disk and the read-write head. As such, it is important to inspect articles with apparatus and methods herein to correct manufacturing trends leading to surface and/or subsurface defects and to increase product quality.

FIG. 1 provides a schematic for detection and/or mapping of surface features of articles, illustrating an apparatus 100 comprising a photon emitter 110, an optical setup 120, a photon detector array 130, and a mapping means 140, as well as an article 150 and a surface features map 160 of a surface of the article 150 in accordance with an embodiment; however, the articles and apparatuses of the invention, as well as methods of the invention, are not limited to the embodiments in FIG. 1, as additional embodiments of the invention may be realized by the features described in more detail herein.

An apparatus for detection and/or mapping of surface features of articles may comprise a single photon emitter (e.g., see photon emitter 110 of FIG. 1) or a plurality of photon emitters, which may be used to emit photons onto a surface of an article, such as the entire surface of the article or some predetermined portion of the surface of the article (e.g., for gradational rotation of the article for piecewise inspection, if desired). In some embodiments, for example, the plurality of photon emitters may comprise at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 photon emitters. In some embodiments, for example, the plurality of photon emitters may comprise no more than 10, 9, 8, 7, 6, 5, 4, 3, or 2 photon emitters. Combinations of the foregoing may also be used to describe the plurality of photon emitters. In some embodiments, for example, the plurality of photon emitters may comprise at least 2 photon emitters and no more than 10 photon emitters (e.g., between 2 and 10 photon emitters), such as at least 2 photon emitters and no more than 5 photon emitters (e.g., between 2 and 5 photon emitters). Further with respect to the plurality of photon emitters, each photon emitter of the plurality of photon emitters may be the same or different, or some combination thereof (e.g., at least 2 of the same photon emitter, with the remainder of photon emitters being different; at least 3 of the same photon emitter, with the remainder of photon emitters being different; etc.).

Whether the apparatus for detection and/or mapping of surface features of articles comprises a single photon emitter or a plurality of photon emitters, each photon emitter may emit photons onto a surface of an article at an optimized distance and/or optimized angle for one or more types of features, which types of features are described in more detail herein. The angle optimized for one or more types of features may be equal to the angle of incidence, which is the angle between a ray comprising the emitted photons incident on the surface of the article and the normal (i.e., a line perpendicular to the surface of the article) at the point at which the ray is incident. FIG. 2 provides a number of rays comprising emitted photons incident on a surface 152 of an article 150 that form an angle of incidence with the normal to the surface. A photon emitter may be optimized to emit photons at an angle of incidence ranging from 0° to 90°, wherein an angle of incidence of 0° represents the photon emitter emitting photons onto the surface of the article from a side of the article, and wherein an angle of incidence of 90° represents the photon emitter emitting photons onto the surface of the article from directly above the article. In some embodiments, for example, a photon emitter may emit photons onto a surface of an article such that the angle of incidence is at least 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, or 90°. In some embodiments, for example, a photon emitter may emit photons onto a surface of an article such that the angle of incidence is no more than 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15°, 10°, or 5°. Combinations of the foregoing may also be used to describe the angle of incidence at which a photon emitter may emit photons onto a surface of an article. In some embodiments, for example, a photon emitter may emit photons onto a surface of an article such that the angle of incidence is at least a 0° and no more than 90° (i.e., between 0° and 90°), such as least 0° and no more than 45° (i.e., between 0° and 45°), including at least 45° and no more than 90° (i.e., between 45° and 90°).

A photon emitter, optionally in combination with one or more additional photon emitters, and further optionally in combination with one or more additional photon emitters of the same type, may emit photons onto a surface of an article, such as the entire surface or some predetermined portion of the surface (e.g., for gradational rotation of the article for piecewise inspection, if desired). The photon emitter, optionally in combination with the one or more additional photon emitters, and further optionally in combination with the one or more additional photon emitters of the same type, may further emit photons onto the entire surface of the article or some predetermined portion of the surface such that the entire surface or the predetermined portion of the surface is uniformly or homogenously illuminated. Uniformly illuminating the entire surface of the article or some predetermined portion of the surface includes, but is not limited to, subjecting the entire surface of the article or some predetermined portion of the surface of the article to the same or about the same photon energy per unit time (e.g., photon power or photon flux) and/or photon power per unit area (e.g., photon flux density). In radiometric terms, uniformly illuminating includes, but is not limited to, subjecting the entire surface of the article or some predetermined portion of the surface of the article to the same or about the same radiant energy per unit time (e.g., radiant power or radiant flux) and/or radiant power per unit area (e.g., irradiance or radiant flux density).

With the appreciation that photons are the elementary particles of electromagnetic radiation or light, a photon emitter or light source may provide light comprising a relatively wide range of wavelengths (e.g., ultraviolet-visible, visible, infrared, etc.), a relatively narrow range of wavelengths (e.g., a subdivision of ultraviolet such as UVA, UVB, UVC, etc.; a subdivision of visible such as red, green, blue, etc.; a subdivision of infrared such as near infrared, mid-infrared; etc.), or a particular wavelength (e.g., monochromatic); light comprising a relatively wide range of frequencies (e.g., ultraviolet-visible, visible, infrared, etc.), a relatively narrow range of frequencies (e.g., a subdivision of ultraviolet such as UVA, UVB, UVC, etc.; a subdivision of visible such as red, green, blue, etc.; a subdivision of infrared such as near infrared, mid-infrared; etc.), or a particular frequency (e.g., monochromatic); polarized (e.g., linear polarization, circular polarization, etc.) light, partially polarized light, or nonpolarized light; and/or light with different degrees of temporal and/or spatial coherence ranging from coherent light (e.g., laser) to noncoherent light. As discussed herein, a photon emitter or light source may be used in conjunction with one or more optical components of an optical setup to provide light having any of the foregoing qualities.

In view of the foregoing, a photon emitter or light source may comprise a lamp such as a flash lamp, including a high-speed flash lamp, configured to minimize vibration while detecting photons scattered from features in a surface of an article with a photon detector array. In some embodiments, for example, a photon emitter or light source may comprise a high-speed Xe flash lamp such as a 500 W Xe flash lamp to minimize vibration while detecting photons scattered from features in a surface of an article with a photon detector array.

Also in view of the foregoing, a photon emitter or light source may comprise a collimated light source such as a laser, including a combination of lasers, configured to emit photons onto a surface of an article at one or more angles. In some embodiments, for example, a combination of lasers may be provided to a laser beam shaper such that the combination of lasers emits photons onto a surface of an article at one angle. In some embodiments, for example, a combination of lasers may be provided to a laser beam shaper such that the combination of lasers emits photons onto a surface of an article at multiple angles. In some embodiments, for example, at least 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, or 30 lasers (or more) may be provided to a laser beam shaper such that the combination of lasers emits photons onto a surface of an article at one or more angles. In some embodiments, for example, no more than 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, or 2 lasers may be provided to a laser beam shaper such that the combination of lasers emits photons onto a surface of an article at one or more angles. Combinations of the foregoing may also be used to describe combinations of lasers provided to a laser beam shaper. In some embodiments, for example, at least 2 lasers and no more than 30 lasers (e.g., between 2 and 30 lasers), such as at least 10 lasers and no more than 30 lasers (e.g., between 10 and 30 lasers), including at least 20 lasers and no more than 30 lasers (e.g., between 20 and 30 lasers), and further including at least 24 lasers and no more than 28 lasers (e.g., between 24 and 28 lasers) may be provided to a laser beam shaper such that the combination of lasers emits photons onto a surface of an article at one or more angles.

Further in view of the foregoing, a photon emitter or light source may comprise a two-dimensional light source such as a combination of point light sources, including a linear combination, an arcuate combination, etc. of point light sources configured to emit photons onto a surface of an article. In some embodiments, for example, a two-dimensional light source may comprise a combination of at least 10, 20, 40, 60, 80, 100, 110, 120, 140, 160, 180, or 200 (or more) point light sources. In some embodiments, for example, a two-dimensional light source may comprise a combination of no more than 200, 180, 160, 140, 120, 100, 80, 60, 40, 20, or 10 point light sources. Combinations of the foregoing may also be used to describe two-dimensional light sources comprising combinations of point light sources. In some embodiments, for example, a two-dimensional light source may comprise a combination of at least 10 and no more than 200 (e.g., between 10 and 200) point light sources, such as at least 40 and no more than 160 (e.g., between 40 and 160) point light sources, including at least 60 and no more than 140 (e.g., between 60 and 140) point light sources, and further including at least 80 and no more than 120 (e.g., between 80 and 120) point light sources. Such point light sources may be linearly combined to form a two-dimensional light source such as a strip light. Such point light sources may be arcuately combined to form a two-dimensional light source such as a ring light. In some embodiments, for example, a photon emitter or light source may comprise a two-dimensional light source comprising at least 60 point light sources, such as a ring light comprising at least 60 point light sources, including a ring light comprising at least 60 light-emitting diodes (“LEDs”), and further including a ring light comprising at least 100 LEDs. A two-dimensional light source comprising LEDs may comprise white LEDs, wherein each LED has a power of at least 10 mW. An LED-based ring light may enhance features such as scratches (e.g., circumferential scratches) and/or voids in surfaces of articles, especially when the LED-based ring light is configured to emit photons onto the surfaces of the articles with lower angles (e.g., angle of incidence equal to or less than) 45°.

An apparatus for detection and/or mapping of surface features of articles may further comprise an optical setup (e.g., see optical setup 120 of FIG. 1), which optical setup may manipulate photons emitted from one or more photon emitters and/or photons scattered from surface features of articles. With the appreciation that photons are the elementary particles of electromagnetic radiation or light, the optical setup may manipulate light emitted from one or more photon emitters and/or light scattered from surface features of articles. The optical setup may comprise any of a number of optical components placed in the optical path before an article such that the optical components may be used to manipulate photons/light emitted from one or more photon emitters before uniformly or homogenously illuminating the entire surface or the predetermined portion of the surface of the article. The optical setup may comprise any of a number of optical components placed in the optical path after an article such that the optical components may be used to manipulate photons/light scattered from features in a surface of the article. The forgoing optical components may include, but are not limited to, optical components such as lenses, mirrors, and filters. With respect to optical components such as filters, such filters may include, for example, wave filters and polarization filters. Wave filters may be used in conjunction with photon emitters described herein to provide light comprising a relatively wide range of wavelengths/frequencies, a relatively narrow range of wavelengths/frequencies, or a particular wavelength/frequency. Polarization filters may be used in conjunction with photon emitters described herein to provide light of a desired polarization including polarized light, partially polarized light, or nonpolarized light.

An optical setup for an apparatus for detection and/or mapping of surface features of articles may comprise a single lens or a plurality of lenses, including, but not limited to, a combination of a lens coupled to a photon detector array (e.g., photon detector array 130 of FIG. 1) for collecting and detecting photons scattered from features in a surface of an article. The lens coupled to the photon detector array may be an objective lens, such as a telecentric lens, including an object-space telecentric lens (i.e., entrance pupil at infinity), an image-space telecentric lens (i.e., exit pupil at infinity), or a double telecentric lens (i.e., both pupils at infinity). Coupling a telecentric lens to a photon detector array reduces errors with respect to the mapped position of surface features of articles, reduces distortion of surface features of articles, and/or enables quantitative analysis of photons scattered from surface features of articles, which quantitative analysis includes integration of photon scattering intensity distribution for size determination of surface features of articles.

To detect photons scattered from surface features of articles, an apparatus for detection and/or mapping of surface features of articles may further comprise a single photon detector array (e.g., see photon detector array 130 of FIG. 1) comprising a plurality of photon detectors or a plurality of photon detector arrays, each comprising a plurality of photon detectors. In some embodiments, for example, the plurality of photon detector arrays may comprise at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 photon detector arrays. In some embodiments, for example, the plurality of photon detector arrays may comprise no more than 10, 9, 8, 7, 6, 5, 4, 3, or 2 photon detector arrays. Combinations of the foregoing may also be used to describe the plurality of photon detector arrays. In some embodiments, for example, the plurality of photon detector arrays may comprise at least 2 photon detector arrays and no more than 10 photon detector arrays (e.g., between 2 and 10 photon detector arrays), such as at least 2 photon detector arrays and no more than 5 photon detector arrays (e.g., between 2 and 5 photon detector arrays). Further with respect to the plurality of photon detector arrays, each photon detector array of the plurality of photon detector arrays may be the same or different, or some combination thereof (e.g., at least 2 of the same photon detector array, with the remainder of photon detector arrays being different; at least 3 of the same photon detector array, with the remainder of photon detector arrays being different; etc.).

Whether the apparatus comprises a single photon detector array or a plurality of photon detector arrays, each photon detector array may be oriented to detect photons scattered from surface features of an article at an optimized distance and/or an optimized angle for a maximum acceptance of scattered light and/or one or more types of features, which types of features are described in more detail herein. Likewise, a photon detector array and lens (e.g., telecentric lens) combination may be oriented to collect and detect photons scattered from surface features of an article at an optimized distance and/or an optimized angle for a maximum acceptance of scattered light and/or one or more types of features. Such an optimized angle may be the angle between a ray comprising the center line axis of the photon detector array and/or the lens extended to the surface of the article and the normal (i.e., a line perpendicular to the surface of the article) at the point at which the ray is extended. The optimized angle may be equal to or otherwise include a scatter angle for one or more types of features, and the scatter angle may be a different angle than the angle of reflection, which angle of reflection is equal to the angle of incidence as described herein. FIG. 2 provides a number of rays comprising scattered photons from a feature 154 on a surface 152 of an article 150 that form various scatter angles, as well as a number of rays comprising reflected photons that form an angle of reflection with the normal to the surface. A photon detector array or photon detector array and lens combination may be oriented at an optimized angle ranging from 0° to 90°, wherein an optimized angle of 0° represents orientation of the photon detector array or the photon detector array and lens combination at a side of the article, and wherein an optimized angle of 90° represents orientation of the photon detector array or photon detector array and lens combination directly above the article. In some embodiments, for example, a photon detector array or photon detector array and lens combination may be oriented at an optimized angle of at least 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, or 90°. In some embodiments, for example, a photon detector array or photon detector array and lens combination may be oriented at an optimized angle of no more than 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15°, 10°, or 5°. Combinations of the foregoing may also be used to describe the optimized angle at which the photon detector array or photon detector array and lens combination may be oriented. In some embodiments, for example, a photon detector array or photon detector array and lens combination may be oriented at an optimized angle of at least a 0° and no more than a 90° (i.e., between 0° and 90°), such as least 0° and no more than 45° (i.e., between 0° and 45°), including at least 45° and no more than 90° (i.e., between 45° and 90°).

A photon detector array, optionally in combination with a lens (e.g., telecentric lens), and further optionally in combination with one or more additional photon detector arrays or photon-detector-array-and-lens combinations, and even further optionally in combination with one or more additional photon detector arrays or photon-detector-array-and-lens combinations of the same type, may detect photons scattered from features in a surface of an article, such as the entire surface of the article or some predetermined portion of the surface of the article. The photon detector array, optionally in combination with a lens (e.g., telecentric lens), and further optionally in combination with one or more additional photon detector arrays or photon-detector-array-and-lens combinations, and even further optionally in combination with one or more additional photon detector arrays or photon-detector-array-and-lens combinations of the same type, may detect photons scattered from features in a surface of an article, such as the entire surface of the article or some predetermined portion of the surface of the article, while oriented at a distance and/or an angle optimized for a maximum acceptance of scattered light and/or one or more types of features. As provided herein, the angle optimized for one or more types of features may be equal to or otherwise include a scatter angle for one or more types of features.

With the appreciation that photons are the elementary particles of electromagnetic radiation or light, a photon detector array or light detector array may detect light comprising a relatively wide range of wavelengths (e.g., ultraviolet-visible, visible, infrared, etc.), a relatively narrow range of wavelengths (e.g., a subdivision of ultraviolet such as UVA, UVB, UVC, etc.; a subdivision of visible such as red, green, blue, etc.; a subdivision of infrared such as near infrared, mid-infrared; etc.), or a particular wavelength (e.g., monochromatic); light comprising a relatively wide range of frequencies (e.g., ultraviolet-visible, visible, infrared, etc.), a relatively narrow range of frequencies (e.g., a subdivision of ultraviolet such as UVA, UVB, UVC, etc.; a subdivision of visible such as red, green, blue, etc.; a subdivision of infrared such as near infrared, mid-infrared; etc.), or a particular frequency (e.g., monochromatic); polarized (e.g., linear polarization, circular polarization, etc.) light, partially polarized light, or nonpolarized light; and/or light with different degrees of temporal and/or spatial coherence ranging from coherent light (e.g., laser) to noncoherent light. As discussed herein, a photon detector array or light detector array may be used in conjunction with one or more optical components of an optical setup to detect light having any of the foregoing qualities.

A photon detector array may comprise a plurality of pixel sensors, which pixel sensors, in turn, may each comprise a photon detector (e.g., a photodiode) coupled to a circuit comprising a transistor configured for amplification. Features of a photon detector array comprising such pixel sensors include, but are not limited to, low temperature operation (e.g., down to −40° C.), low electron noise (e.g., 2-10 eRMS; 1 eRMS; <1 eRMS; etc.), wide dynamic range (e.g., 30,000:1, 8,500:1; 3,000:1; etc.), and/or decreased photon/light collection time. A photon detector array may comprise a large number of pixel sensors (e.g., ≧1,000,000 or 1M pixel sensors) arranged in rows and columns of a two-dimensional array, wherein each pixel sensor comprises a photon detector coupled to an amplifier. In some embodiments, for example, a photon detector array may comprise at least 1M, 2M, 3M, 4M, 5M, 6M, 7M, 8M, 9M, 10M, or more, pixel sensors arranged in rows and columns of a two-dimensional array. In some embodiments, for example, a photon detector array may comprise no more than 10M, 9M, 8M, 7M, 6M, 5M, 4M, 3M, 2M, 1M, pixel sensors arranged in rows and columns of a two-dimensional array. Combinations of the foregoing may also be used to describe the number of pixel sensors in a photon detector array. In some embodiments, for example, a photon detector array may comprise at least 1M and no more than 10M (e.g., between 1M and 10M) pixel sensors arranged in rows and columns of a two-dimensional array, such as at least 1M and no more than 8M (e.g., between 1M and 8M) pixel sensors, including at least 1M and no more than 6M (e.g., between 1M and 6M) pixel sensors, further including at least 2M and no more than 6M (e.g., between 2M and 6M) pixel sensors, and even further including at least 2M and no more than 5M (e.g., between 2M and 5M) pixel sensors.

Due to surface reflections of surface features in articles and/or small angle scattering (e.g., 4π scattering), surface features may appear much larger in size enabling pixel sensors larger the than surface features to be used. In some embodiments, for example, a photon detector array may comprise micrometer-sized (i.e., admits of μm units as measured) pixel sensors at least 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm in their smallest dimension. In some embodiments, for example, a photon detector array may comprise micrometer-sized pixel sensors no more than 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, or 1 μm in their smallest dimension. Combinations of the foregoing may also be used to describe dimensions of micrometer-sized pixel sensors in photon detector arrays. In some embodiments, for example, a photon detector array may comprise micrometer-sized pixel sensors at least 1 μm and no more than 10 μm (e.g., between 1 μm and 10 μm) in their smallest dimension, such as at least 1 μm and no more than 7 μm (e.g., between 1 μm and 7 μm), including at least 4 μm and no more than 10 μm (e.g., between 4 μm and 10 μm), and further including at least 4 μm and no more than 7 μm (e.g., between 4 μm and 7 μm). Such micrometer-sized pixel sensors may be used in the apparatus to detect and/or map surface features of articles that are more than 100 times smaller than the micrometer-sized pixel sensors.

In view of the foregoing, the single photon detector array or the plurality of photon detector arrays may each comprise a complementary metal-oxide semiconductor (“CMOS”) or a scientific complementary metal-oxide semiconductor (“sCMOS”), each of which may optionally be part of CMOS camera or a sCMOS camera, respectively.

FIG. 3 provides a schematic for detection of surface features in an article, illustrating a close-up, cross-sectional view of an apparatus comprising an optical setup and a photon detector array. As shown, article 150 comprises a surface 152 and at least surface feature 154. Photons emitted from a single photon emitter or a plurality of photon emitters may be scattered by the surface feature 154 and collected and detected by a combination comprising an optical setup 120 coupled to a photon detector array 130, which combination may be place at an optimized distance and/or an optimized angle for a maximum acceptance of scattered photons and/or one or more types of features. The optical setup 120, which may comprise a telecentric lens, may collect and focus the photons scattered from the surface feature 154 onto one or more pixel sensors 132 of photon detector array 130, which one or more pixel sensors each comprises a photon detector coupled to an amplifier. The one or more pixel sensors 132, each of which corresponds to a pixel in a map of an article's surface features, may provide one or more signals to the mapping means for mapping the surface feature 154 as shown, for example, in FIG. 6A, which is a close-up image of the map of surface features provided in FIG. 5, which, in turn, is a close-up image of the map of surface features provided in FIG. 4. The mapping means may subsequently use pixel interpolation for further mapping the surface feature 154 as shown in FIG. 6B.

An apparatus for detection and/or mapping of surface features of articles may further comprise one or more computers or equivalent devices (e.g., devices that include primary and/or secondary memory and one or more processing elements operable to carry out arithmetic and logical operations) loaded with appropriate instructions operable to, but not limited to, convey each article to the apparatus for inspection; position each article for inspection, optionally including gradational rotation of the article for piecewise inspection; hold each article for inspection; insert optical components into the optical setup; remove optical components from the optical setup; position and/or otherwise adjust optical components for inspection; move each photon emitter into position for inspection, wherein the position for inspection may include an optimized photon emitter-article distance and/or angle (e.g., angle of incidence); switch each photon emitter on and off, or otherwise between modes for emitting photons and not emitting photons; move each photon detector array into position for inspection, wherein the position for inspection may include an optimized photon detector array-article distance and/or angle (e.g., scatter angle); switch each photon detector array on and off, or otherwise between modes for detecting photons and not detecting photons; process photon detector array signals, optionally including pixel interpolation for better accuracy (e.g., 10× better than pixel size) with respect to the mapped position of surface features; map surface features of articles from photon detector array signals or processed photon detector array signals; characterize surface features of articles with respect to type (e.g., particle, stains, scratches, voids, etc.) and/or size (e.g., volume from integration of photon scattering intensity distribution); catalog surface features of articles; and determine trends with respect to surface features of articles.

The apparatus comprising the one or more computers or equivalent devices may be operable to detect and/or map surface features of articles that are nanometer-sized (i.e., admits of nm units as measured) or smaller in their smallest dimension (e.g., length, width, height, or depth, depending on the surface feature); however, the apparatus is not limited to mapping surface features of articles that are nanometer-sized or smaller, as the apparatus may be operable to map surface features of articles that are micrometer-sized (i.e., admits of μm units as measured) or larger. In some embodiments, for example, the apparatus comprising the one or more computers or equivalent devices may be operable to map surface features of articles smaller than 500 nm, 250 nm, 200 nm, 150 nm, 125 nm, 110 nm, 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, 10 nm, or 1 nm (10 Å) in their smallest dimension, or even smaller, such as surface features of articles smaller than 9 Å, 8 Å, 7 Å, 6 Å, 5 Å, 4 Å, 3 Å, 2 Å, or 1 Å in their smallest dimension. In view of the foregoing, the apparatus comprising the one or more computers or equivalent devices may be operable to, in some embodiments, for example, map surface features of articles between 0.1 nm and 1000 nm, such as between 0.1 nm and 500 nm, including between 0.1 nm and 250 nm, and further including between 0.1 nm and 100 nm, and even further including between 0.1 nm and 80 nm.

In view of the foregoing, the apparatus may be operable to detect and/or map surface features of articles such as particle contamination comprising particles that are nanometer-sized (i.e., admits of nm units as measured) or smaller in their smallest dimension (e.g., length, width, or height). In some embodiments, for example, the apparatus may be operable to detect and/or map surface and/or subsurface particles smaller than 125 nm, such as smaller than 100 nm, including smaller than 80 nm, and further including smaller than 10 nm in their smallest dimension. In some embodiments, for example, the apparatus may be operable to map surface and/or subsurface particles smaller than 4 nm in height.

Further in view of the foregoing, the apparatus may be operable to detect and/or map surface features of articles such as defects comprising scratches (e.g., circumferential scratches) that are micrometer-sized (i.e., admits of μm units as measured) or smaller, such as nanometer-sized (i.e., admits of nm units as measured) or smaller, such as angstrom-sized (i.e., admits of Å units as measured) or smaller, in their smallest dimension (e.g., length, width, or depth). With respect to micrometer-sized scratches, the apparatus may be operable to detect and/or map scratches from, for example, 1 μm to 1000 μm in length, which may be significantly longer than the wavelength of photons/light emitted from a photon emitter of the apparatus. In some embodiments, for example, the apparatus may be operable to detect and/or map surface features such as defects comprising scratches smaller than 1000 μm, such as smaller than 500 μm, including smaller than 250 μm, further including smaller than 100 μm, and even further including smaller than 50 μm in scratch length. With respect to nanometer-sized scratches, the apparatus may be operable to detect and/or map scratches from, for example, 1 nm to 500 nm in scratch width. In some embodiments, for example, the apparatus may be operable to detect and/or map surface features such as defects comprising scratches smaller than 500 nm, such as smaller than 250 nm, including smaller than 100 nm, further including smaller than 50 nm, and even further including smaller than 15 nm in scratch width. Surprisingly, due to a high level of spatial coherence, the apparatus may be operable to detect and/or map angstrom-sized scratches with respect to scratch depth. In some embodiments, for example, the apparatus may be operable to detect and/or map surface features such as defects comprising scratches smaller than 50 Å, such as smaller than 25 Å, including smaller than 10 Å, further including smaller than 5 Å, and even further including smaller than 1 Å (e.g., 0.5 Å) in scratch depth. For example, the apparatus may be operable to detect and/or map surface features such as defects comprising scratches smaller than 500 μm in length, smaller than 100 nm in width, and smaller than 50 Å in depth.

The apparatus comprising the one or more computers or equivalent devices may be operable to accurately and/or precisely map the position of a feature on an article's surface. With respect to accuracy, the apparatus comprising the one or more computers or equivalent devices may be operable to map the position of a feature on an article's surface within a micrometer-sized (i.e., admits of μm units as measured) radius or better. In some embodiments, for example, the apparatus comprising the one or more computers or equivalent devices may be operable to accurately map the position of a feature on an article's surface within a radius of 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, or 1 μm, or better. Combinations of the foregoing may also be used to describe the accuracy with which the apparatus comprising the one or more computers or equivalent devices may map the position of a feature on an article's surface. In some embodiments, for example, the apparatus comprising the one or more computers or equivalent devices may be operable to accurately map the position of a feature on an article's surface within a radius ranging from 1 μm to 100 μm, such as from 1 μm to 50 μm, including from 1 μm to 30 μm, and further including from 5 μm to 10 μm.

The apparatus comprising the one or more computers or equivalent devices may be operable to accurately and/or precisely map the position of a feature on an article's surface (e.g., FIGS. 6A (top) and 6B (top)) along with the feature's photon scattering intensity distribution (e.g., FIGS. 6A (bottom) and 6B (bottom)). Mathematical integration of such a photon scattering intensity distribution provides the size (e.g., volume) of the respective feature. As such, the apparatus described herein may characterize surface features both qualitatively and quantitatively. With respect to qualitative characterization of surface features, qualitative characterization includes a determination of surface feature type (e.g., particle, stain, scratch, void, etc.). With respect to quantitative characterization of surface features, quantitative characterization includes a determination of surface feature position on the article and/or surface feature size. Quantitative characterization of surface features may further include the total number of surface features per article, as well as the number of each type of surface feature. Such characterization information may be cataloged across a plurality of articles and be used to correct manufacturing trends leading to surface and/or subsurface defects.

Depending upon factors that may include the type of article, the type of surface features, and the like, it may be desirable at times to increase the number of photons (e.g., photon energy) emitted from a single photon emitter or a plurality of photon emitters to provide an increased scattering signal for characterization (e.g., qualitative and/or quantitative) of surface features of articles. Such an increase in photon energy may be with respect to unit time for increased photon power or photon flux, or with respect to unit area for increased photon flux density. Alternately, or in addition, it may be desirable to increase detection time of a single photon emitter or a plurality of photon emitters to detect more photons for accurately and/or precisely mapping surface features. Alternately to one or both of increasing the photon energy or detection time, or in addition to increasing the photon energy and detection time, it may be desirable at times to minimize background noise including stray light from one or more photon emitters, background light, and/or background fluorescent radiation.

The apparatus described herein may be configured to process or inspect articles at a rate greater than or commensurate with the rate at which the articles or workpieces thereof are produced. In some embodiments, for example, the apparatus may be configured to process or inspect articles at a rate of at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, or 20 article(s) per second, which rate may be commensurate with the rate at which the articles or workpieces thereof are produced. In some embodiments, for example, the apparatus may be configured to process or inspect articles at a rate of no more than 20, 18, 16, 14, 12, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 article(s) per second, which rate may be commensurate with the rate at which the articles or workpieces thereof are produced. Combinations of the foregoing may also be used to describe the rate at which the articles or workpieces thereof are processed or inspected by the apparatus. In some embodiments, for example, the apparatus may be configured to process or inspect at least 1 and no more than 20 articles per second (e.g., between 1 and 20 articles per second), such as at least 1 and no more than 10 articles per second (e.g., between 1 and 10 articles per second), including at least 1 and no more than 5 articles per second (e.g., between 1 and 5 articles per second). Processing or inspecting articles at rates greater than or commensurate with the rate at which the articles or workpieces thereof are produced is a function of many features of the apparatus described herein, including, but not limited to, photon emitters and/or articles that need not be moved (e.g., for scanning) during processing or inspecting. For example, an article such as a hard disk of a hard disk drive need not be rotated during processing or inspecting. As such, the apparatus may be configured to hold an article stationary while emitting photons onto the surface of the article.

While the apparatus may be configured to process or inspect articles a rate greater than or commensurate with the rate at which the articles or workpieces thereof are produced, the apparatus may operate at a slower rate if needed. In some embodiments, for example, the apparatus may be configured to process or inspect articles at a rate less than one article per second. In such embodiments, for example, the apparatus may be configured to process or inspect articles at a rate less than one article per 5, 10, 25, 50, 75, or 100, or more, second(s).

The apparatus described herein comprising a photon emitter, an optical setup, a photon detector array, and a mapping means may be fully automated and function in different modes, including, but not limited to, an ultrafast mode, an ultrasensitive mode, and ultrasensitive plus mode. With respect to the ultrafast mode, the apparatus may operate at least 200 times faster than an optical surface analyzer (e.g., KLA-Tencor Candela CS10 or CS20), detect surface features such as defects comprising embedded particles down to at least 100 nm, partially detect surface features such as defects comprising scratches (e.g., nanometer-sized scratches), and provide measurements of roughness. With respect to the ultrasensitive mode, the apparatus may operate at least 50 times faster than an optical surface analyzer, detect surface features such as defects comprising embedded particles down to at least 30 nm, and provide measurements of roughness. With respect to the ultrasensitive plus mode, the apparatus may operate at least 20 times faster than an optical surface analyzer, detect surface features such as defects comprising embedded particles down to at least 30 nm, fully detect surface features such as defects comprising scratches (e.g., nano-scratches), and provide measurements of roughness.

As such, as provided herein, is an apparatus, comprising a photon emitter configured to emit photons onto a surface of an article, a photon detector array comprising a plurality of photon detectors configured to receive photons scattered from features in the surface of the article; and a mapping means for mapping the features in the surface of the article, wherein the apparatus is configured to characterize the features in the surface of the article by analyzing the photons received at the plurality of photon detectors. In some embodiments, the apparatus is configured to hold the article in a stationary position while emitting photons onto the surface of the article. In some embodiments, the apparatus further comprises a telecentric lens, wherein the telecentric lens is coupled to the photon detector array. In some embodiments, the apparatus is operable to process articles at a rate faster than one article every 100 seconds. In some embodiments, the apparatus is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the apparatus is operable to map features greater than 0.10 nm in their smallest dimension. In some embodiments, the mapping means is operable to map features with at least a 10-μm accuracy with respect to location.

Also provided herein is an apparatus, comprising a photon emitter configured to emit photons onto a surface of an article, a photon detector array comprising a plurality of photon detectors configured to receive photons scattered from features in the surface of the article; and a mapping means for mapping the features in the surface of the article, wherein the apparatus is operable to process articles at a rate faster than one article every 100 seconds. In some embodiments, the apparatus is configured to hold the article in a stationary position while emitting photons onto the surface of the article. In some embodiments, the apparatus further comprises a telecentric lens, wherein the telecentric lens is coupled to the photon detector array. In some embodiments, the apparatus is operable to process articles at a rate faster than one article per second. In some embodiments, the apparatus is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the apparatus is operable to map features greater than 0.10 nm in their smallest dimension. In some embodiments, the mapping means is operable to map features down to at least a 10-μm precision with respect to location.

Also provided is an apparatus, comprising a photon emitter configured to emit photons onto a surface of an article; a telecentric lens; a photon detector array comprising a plurality of photon detectors coupled to the lens configured to receive photons scattered from one or more features in the surface of the article; and a mapping means for mapping the one or more features in the surface of the article, wherein the apparatus is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the apparatus is configured to hold the article in a stationary position while emitting photons onto the surface of the article. In some embodiments, the apparatus is operable to process articles at a rate faster than one article every 100 seconds. In some embodiments, the apparatus is operable to process articles at a rate faster than one article per second. In some embodiments, the apparatus is operable to map features smaller than 25 nm in their smallest dimension. In some embodiments, the apparatus is operable to map features greater than 0.10 nm in their smallest dimension. In some embodiments, the mapping means is operable to map features with at least a 10-μm accuracy with respect to location.

Also provided is an apparatus, comprising a photon emitter configured to emit photons onto a surface of an article; a telecentric lens; a photon detector array coupled to the lens configured to receive photons scattered from one or more features in the surface of the article; and a mapping means for mapping the one or more features in the surface of the article, wherein the apparatus is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the apparatus is configured to hold the article in a stationary position while emitting photons onto the surface of the article. In some embodiments, the apparatus is operable to process articles at a rate faster than one article every 100 seconds. In some embodiments, the apparatus is operable to process articles at a rate faster than one article per second. In some embodiments, the apparatus is operable to map features smaller than 25 nm in their smallest dimension. In some embodiments, the apparatus is operable to map features greater than 0.10 nm in their smallest dimension. In some embodiments, the mapping means is operable to map features down to at least a 10-μm precision with respect to location.

Also provided is an apparatus, comprising a photon emitting means for emitting photons onto a surface of an article, a photon detecting means for detecting photons scattered from features in the surface of the article; and a mapping means for mapping the features in the surface of the article, wherein the apparatus is operable to process articles at a rate faster than one article every 100 seconds. In some embodiments, the apparatus is configured to hold the article in a stationary position while emitting photons onto the surface of the article. In some embodiments, the article is greater than 500 square micrometers. In some embodiments, the apparatus is operable to process articles at a rate faster than five article per second. In some embodiments, the apparatus is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the mapping means is further for analyzing scattering intensity distribution of photons scattered from features in the surface of the article.

Also provided is an apparatus, comprising a photon emitting means for emitting photons onto a surface of an article, a photon detecting means for detecting photons scattered from features in the surface of the article; and a mapping means for mapping the features in the surface of the article, wherein the mapping means is operable to map features down to at least a 10-μm precision with respect to location. In some embodiments, the apparatus is configured to hold the article in a stationary position while emitting photons onto the surface of the article. In some embodiments, the apparatus is operable to process articles at a rate faster than one article every 100 seconds. In some embodiments, the apparatus is operable to process articles at a rate faster than one article per second. In some embodiments, the apparatus is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the mapping means is further configured to map scattering intensity distribution of photons scattered from features in the surface of the article.

Also provided herein is a device, comprising a feature mapper configured to map features about a surface of an article from signals provided by a photon detector array, wherein the signals correspond to photons scattered from the features about the surface of the article, and wherein the feature mapper is configured for characterizing the features about the surface of the article by analyzing the photons received at the photon detector array. In some embodiments, the feature mapper is configured for qualitatively and/or quantitatively characterizing the features about the surface of the article. In some embodiments, quantitatively characterizing the features about the surface of the article comprises determining the size and/or number of features about the surface of the article. In some embodiments, the device is operable to map features smaller than 80 nm in their smallest dimension. In some embodiments, the device is operable to process articles at a rate faster than one article every 100 seconds.

While the invention has been described and/or illustrated by means of particular embodiments and/or examples, and while these embodiments and/or examples have been described in considerable detail, it is not the intention of the applicant(s) to restrict or in any way limit the scope of the invention to such detail. Additional adaptations and/or modifications of the invention may readily appear to persons having ordinary skill in the art to which the invention pertains, and, in its broader aspects, the invention may encompass these adaptations and/or modifications. Accordingly, departures may be made from the foregoing embodiments and/or examples without departing from the scope of the invention, which scope is limited only by the following claims when appropriately construed.