US5108176A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of calibrating scanners and arrangement for producing defined scattered light amplitudes
Assignee: Tencor Instruments Inc
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Filing: 1990-05-21
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Granted: 1992-04-28
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Expires: 2010-05-21
Abstract
Abstract Calibration of a light scanner, particularly for measuring particles and surface finishes in the inspection of substrates uses a strongly scattering reference medium. A focused laser beam is directed onto the reference medium which is disposed outside the focal plane of the beam. Scattered light from the medium is thus defocused with respect to a photodetector that collects the scattered light. An amplifier connected to the photodetector measures the intensity of the scattered light. By the use of filters in the path of the light calibration of the optico-electronic system of the scanner is achieved.
Inventors
- 👤 Cosmas Malin
- 👤 Philip Hoyle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:44
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/93; G01N21/17; G01N21/47; G01N21/4785
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
97 words
A method of calibrating a light scanner comprising the steps of directing illumination from a light scanner onto a scattering reference medium having a known scattering capacity, collecting a portion of the scattered light by means of an optical system having a focal plane, defocusing the scattered light collected from the reference medium by disposing the reference medium out of the focal plane of the optical system, measuring the amplitude of the scattered light so defocused whereby the local dependence of the scattered light amplitude is eliminated by defocusing the scattered light collected from the reference medium.
Claim 2
Independent Claim
97 words
A method of calibrating a light scanner comprising the steps of directing illumination from a light scanner onto a scattering reference medium having a known scattering capacity, collecting a portion of the scattered light by means of an optical system having a focal plane, defocusing the scattered light collected from the reference medium by disposing the reference medium out of the focal plane of the optical system, measuring the amplitude of the scattered light so defocused whereby the local dependence of the scattered light amplitude is eliminated by defocusing the scattered light collected from the reference medium.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein the reference medium onto which the illumination is directed has a surface of predetermined scattering capacity.
Claim 4
Dependent Claim
20 words
A method according to claim 1, wherein the reference medium has a volume effecting the scattering capacity of the medium.
Claim 5
Dependent Claim
18 words
A method according to claim 1, wherein a body of milk glass is used as a reference medium.
Claim 6
Dependent Claim
42 words
A method according to claim 1 including the additional steps of replacing the reference medium with a substrate having a surface to be inspected, and repeating the steps of directing, defocusing and measuring for measuring particles and surface finish on the substrate.
Claim 7
Dependent Claim
90 words
An arrangement for producing defined scattered light amplitudes comprising, in combination, a light source for producing a beam of light, an optical filter in the path of said beam, a scattering reference medium with a known scattering capacity, means for directing the beam onto said medium, a photodetector for light from said beam scattered by the reference medium, means including a collecting lens for defocusing light scattered by the reference medium with respect to said photodetector and an amplifier for the output generated by said scattered light on the photodetector.
Claim 8
Dependent Claim
90 words
An arrangement for producing defined scattered light amplitudes comprising, in combination, a light source for producing a beam of light, an optical filter in the path of said beam, a scattering reference medium with a known scattering capacity, means for directing the beam onto said medium, a photodetector for light from said beam scattered by the reference medium, means including a collecting lens for defocusing light scattered by the reference medium with respect to said photodetector and an amplifier for the output generated by said scattered light on the photodetector.
Claim 9
Dependent Claim
21 words
An arrangement according to claim 6, wherein a confocal optical system is employed for directing the scattered light to the photodetector.
Claim 10
Dependent Claim
37 words
An arrangement according to claim 6 wherein the means for directing the beam onto the reference medium is focused on a focal plane of the collecting lens and the reference medium is disposed outside the focal plane.
Claim 11
Dependent Claim
14 words
An arrangement according to claim 6 wherein the reference medium is a milk glass.
References Cited (Backward Citations)
US4776693A
Cited
US4966457A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-04-28 | 1995-10-28 | 1996-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-04-28 | 1999-10-28 | 2000-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-04-28 | 2003-10-28 | 2004-04-28 | $7700.00 | Window Closed / Lapsed |