Patent US3813173A successfully refreshed from Google Patents.
US3813173A
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Defect sensing apparatus and method
Assignee: Corning Glass Works
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Filing: 1972-02-22
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Granted: 1974-05-28
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Expires: 1992-02-22
Abstract
Abstract Apparatus for and method of sensing or detecting defects such as so-called pin holes in transparent thin films which are deposited on a surface of a transparent substrate either originally in the form of a thin film microcircuit pattern or for the subsequent purpose of making a microcircuit pattern out of a deposited film covering the entire surface of the substrate. The substrate and its film are illuminated by a collimated source of white or suitably filtered light and are imaged or focused through a first lens system or Fourier transform lens at a point on one side of a light trap or dark field stop. When the thin film is in the form of a microcircuit pattern, a negative of a Fourier transform of a defect-free microcircuit identical in pattern to the pattern imaged through the transform lens is required to be used as the light trap or dark field stop. However, when the thin film covers the entire surface of the substrate a conventional or basic form of light trap may be used. A defect such as a pin hole in the illuminated film diffracts the light rays passing through the pin hole and these rays are imaged or focused through a second lens system at a point in an image plane in advance of the lens of a vidicon tube or television camera. A rotating filter preferably comprising a transparent disk having on selected alternate segments of one face thereof a thin film of the same material as the film on the substrate, or a film of similar light absorbing characteristics, is disposed between the image plane and the camera lens. The arrangement causes flashing on and off of the images of pin holes in the thin film on the substrate while images of other defects such as dust or finger prints on the substrate remain steadily on. Various modifications of the rotating filter are possible or practicable.
Inventors
- 👤 M Teter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:48
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95623; G02; G02B; G02B27/00; G02B27/42; G02B27/46
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
303 words
Apparatus for sensing or detecting defects such as pin holes in a transparent thin film provided on a surface of a transparent substrate and distinguishing such defects from blemishes such as dust particles on such substrate, such thin film substantially absorbing colors of first wavelengths and substantially transmitting colors of other wavelengths, such apparatus comprising, in combination; A. a source of white light, B. light collimator means disposed in a transmittance path of light rays transmitted from said source, said substrate disposed for illumination thereof by collimated light rays transmitted from the collimator means, C. a Fourier transform lens disposed in the transmittance path of the collimated light rays transmitted from said substrate, D. a light trap disposed about a focal length from said transform lens in the transmittance path of light rays transmitted from said substrate and said transform lens for substantially blocking undiffracted light rays transmitted through said substrate, E. an image lens disposed in the path of transmittance of diffracted light rays transmitted from said transform lens and said light trap, F. movable light filter means disposed in the path of transmittance of light rays transmitted from said image lens for substantially absorbing colors either of said first wavelengths or of said other wavelengths, such means comprising at least one transparent thin film support member having on a surface thereof a transparent thin film filter, G. means intermittently moving said filter means into and out of the path of transmittance of light rays transmitted from said image lens, and H. light responsive display means disposed in the path of transmittance of light rays transmitted from said image lens and filter means, I. whereby a defect such as a pin hole in said thin film on said substrate will be displayed differently from blemishes such as dust particles on the substrate.
Claim 2
Dependent Claim
303 words
Apparatus for sensing or detecting defects such as pin holes in a transparent thin film provided on a surface of a transparent substrate and distinguishing such defects from blemishes such as dust particles on such substrate, such thin film substantially absorbing colors of first wavelengths and substantially transmitting colors of other wavelengths, such apparatus comprising, in combination; A. a source of white light, B. light collimator means disposed in a transmittance path of light rays transmitted from said source, said substrate disposed for illumination thereof by collimated light rays transmitted from the collimator means, C. a Fourier transform lens disposed in the transmittance path of the collimated light rays transmitted from said substrate, D. a light trap disposed about a focal length from said transform lens in the transmittance path of light rays transmitted from said substrate and said transform lens for substantially blocking undiffracted light rays transmitted through said substrate, E. an image lens disposed in the path of transmittance of diffracted light rays transmitted from said transform lens and said light trap, F. movable light filter means disposed in the path of transmittance of light rays transmitted from said image lens for substantially absorbing colors either of said first wavelengths or of said other wavelengths, such means comprising at least one transparent thin film support member having on a surface thereof a transparent thin film filter, G. means intermittently moving said filter means into and out of the path of transmittance of light rays transmitted from said image lens, and H. light responsive display means disposed in the path of transmittance of light rays transmitted from said image lens and filter means, I. whereby a defect such as a pin hole in said thin film on said substrate will be displayed differently from blemishes such as dust particles on the substrate.
Claim 3
Dependent Claim
45 words
Apparatus in accordance with claim 1 and further including a second light filter disposed between said source of white light and said collimator means, for substantially transmitting said colors of said first wavelengths and only a selected amount of said colors of said other wavelengths.
Claim 4
Dependent Claim
16 words
Apparatus in accordance with claim 1 and in which said light trap is a Fourier transform.
Claim 5
Dependent Claim
16 words
Apparatus in accordance with claim 2 and in which said light trap is a Fourier transform.
Claim 6
Dependent Claim
39 words
Apparatus in accordance with claim 1 and in which said movable light filter means comprises at least one segment of a circle rotatable into and out of said path of transmittance of light rays transmitted from said image lens.
Claim 7
Dependent Claim
18 words
Apparatus in accordance with claim 1 and in which said transparent thin films are alpha iron oxide films.
Claim 8
Dependent Claim
18 words
Apparatus in accordance with claim 2 and in which said transparent thin films are alpha iron oxide films.
Claim 9
Dependent Claim
18 words
Apparatus in accordance with claim 3 and in which said transparent thin films are alpha iron oxide films.
Claim 10
Dependent Claim
18 words
Apparatus in accordance with claim 4 and in which said transparent thin films are alpha iron oxide films.
Claim 11
Dependent Claim
18 words
Apparatus in accordance with claim 5 and in which said transparent thin films are alpha iron oxide films.
Claim 12
Dependent Claim
250 words
Apparatus for sensing holes in a transparent thin film of alpha iron oxide deposited on a surface of a transparent substrate, such apparatus comprising, in combination, the following sequence of components; A. a light source including a source of white light and a filter transmitting from such source rays of blue light and a limited amount of rays of red light, B. a collimator lens receiving said rays from said light source, C. said substrate disposed for illumination by said lens, D. a first lens system for receiving light rays from said substrate and further transmitting the received light rays, E. a Fourier transform light trap disposed about a focal length from said first lens system in the path of transmittance of said light rays for substantially blocking further transmittance of undiffracted light rays transmitted from said first lens system, F. a second lens system for receiving diffracted light rays from said first lens system and focusing such rays at a point in an image plane, G. a rotatable second filter disposed beyond said point in said image plane for receiving said light rays from said second lens system and substantially absorbing eithEr rays of said blue light or rays of said red light such filter comprising at least one transparent segment of a circle having on a surface thereof a transparent thin film filter, H. a television camera having its lens disposed for receiving light rays from said second filter, and I. motor means for rotating said second filter.
Claim 13
Dependent Claim
250 words
Apparatus for sensing holes in a transparent thin film of alpha iron oxide deposited on a surface of a transparent substrate, such apparatus comprising, in combination, the following sequence of components; A. a light source including a source of white light and a filter transmitting from such source rays of blue light and a limited amount of rays of red light, B. a collimator lens receiving said rays from said light source, C. said substrate disposed for illumination by said lens, D. a first lens system for receiving light rays from said substrate and further transmitting the received light rays, E. a Fourier transform light trap disposed about a focal length from said first lens system in the path of transmittance of said light rays for substantially blocking further transmittance of undiffracted light rays transmitted from said first lens system, F. a second lens system for receiving diffracted light rays from said first lens system and focusing such rays at a point in an image plane, G. a rotatable second filter disposed beyond said point in said image plane for receiving said light rays from said second lens system and substantially absorbing eithEr rays of said blue light or rays of said red light such filter comprising at least one transparent segment of a circle having on a surface thereof a transparent thin film filter, H. a television camera having its lens disposed for receiving light rays from said second filter, and I. motor means for rotating said second filter.
Claim 14
Dependent Claim
22 words
Apparatus in accordance with claim 11 and in which said film on said second filter is a thin alpha iron oxide film.
Claim 15
Independent Claim
194 words
The method of sensing holes in a transparent thin film deposited on a surface of a transparent substrate such film substantially absorbing rays of one color and transmitting rays of other colors and such method comprising, A. illuminating said substrate and film with collimated rays of light from a source of white light, B. illuminating a Fourier transform lens with rays of light from said substrate and film, C. substantially blocking undiffracted rays of light transmitted from said transform lens, D. collecting diffracted rays of light transmitted from said transform lens, E. transmitting said collected rays of light through a point in an image plane and illuminating with the collected rays the pickup lens of a light responsive display device disposed beyond said image plane, and F. intermittently interposing in front of said pickup lens a transparent thin film which substantially absorbs rays either of said one color or of said other colors, G. whereby said display device gives one type of a display for light diffracted by holes in said thin film on said substrate and another type of display for light diffracted by other blemishes such as dust particles on the substrate.
Claim 16
Independent Claim
194 words
The method of sensing holes in a transparent thin film deposited on a surface of a transparent substrate such film substantially absorbing rays of one color and transmitting rays of other colors and such method comprising, A. illuminating said substrate and film with collimated rays of light from a source of white light, B. illuminating a Fourier transform lens with rays of light from said substrate and film, C. substantially blocking undiffracted rays of light transmitted from said transform lens, D. collecting diffracted rays of light transmitted from said transform lens, E. transmitting said collected rays of light through a point in an image plane and illuminating with the collected rays the pickup lens of a light responsive display device disposed beyond said image plane, and F. intermittently interposing in front of said pickup lens a transparent thin film which substantially absorbs rays either of said one color or of said other colors, G. whereby said display device gives one type of a display for light diffracted by holes in said thin film on said substrate and another type of display for light diffracted by other blemishes such as dust particles on the substrate.
Claim 17
Dependent Claim
22 words
The method in accordance with claim 13 and in which said transparent thin films are both thin films of alpha iron oxide.
Claim 18
Dependent Claim
15 words
The method in accordance with claim 13 and in which said one color is blue.
References Cited (Backward Citations)
US3658420A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |