EP0293177A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Apparatus for measuring the thickness of a thin film
Assignee: Kurashiki Spinning Co Ltd
•
Filing: 1988-05-25
•
Granted: —
•
Expires: 2008-05-25
Abstract
Abstract An apparatus for measuring the thickness of a thin film utilizing an interferometric method includes a light source (L) for generating a monochromatic light beam, scanning means (PM) for scanning the light beam on a thin film (F) in such a manner that an incident angle (ϑ) thereto is continuously varied from α to - α, first detecting means (D2) for detecting said incident angle of the light beam and second detection means (D1) for detecting an interference pattern caused by light beams reflected from the top and bottom surfaces of the thin film (F). The thickness of the thin film (F) is obtained in accordance with a geometrical optical relation defined between adjacent fringes contained in the detected interference pattern.
Inventors
- 👤 Katsue Koashi
- 👤 Yosuke Eguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 12:27
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0616; G01B11/0675
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
207 words
An apparatus for measuring the thickness of a thin film utilizing an interferometric method, comprising: light emitting means for generating a monochromatic light beam; deflecting means for deflecting the light beam to scan it; projecting optical system for projecting the deflected light beam on a thin film to be measured in such a manner that an incident angle thereof to the thin film is continuously varied from α to (-α); beam splitter means for splitting the deflected light beam into an impinging beam onto the thin film and a reference beam for detecting an angle of the impinging beam, said beam splitter means being arranged on the optical axis of the projecting optical system; light receiving optical system for detecting an interference pattern caused by interference between two light beams reflected from the top and bottom surfaces of the thin film which is arranged so as to receive two light beams having been reflected by said beam splitter means; angle detecting means for detecting an incident angle of the impinging beam defined with respect to the normal of the thin film; and calculating means for calculating the thickness of the thin film based on an arithmetic relation between two adjacent fringes contained in said interference pattern detected.
Claim 2
Independent Claim
207 words
An apparatus for measuring the thickness of a thin film utilizing an interferometric method, comprising: light emitting means for generating a monochromatic light beam; deflecting means for deflecting the light beam to scan it; projecting optical system for projecting the deflected light beam on a thin film to be measured in such a manner that an incident angle thereof to the thin film is continuously varied from α to (-α); beam splitter means for splitting the deflected light beam into an impinging beam onto the thin film and a reference beam for detecting an angle of the impinging beam, said beam splitter means being arranged on the optical axis of the projecting optical system; light receiving optical system for detecting an interference pattern caused by interference between two light beams reflected from the top and bottom surfaces of the thin film which is arranged so as to receive two light beams having been reflected by said beam splitter means; angle detecting means for detecting an incident angle of the impinging beam defined with respect to the normal of the thin film; and calculating means for calculating the thickness of the thin film based on an arithmetic relation between two adjacent fringes contained in said interference pattern detected.
Claim 3
Dependent Claim
30 words
An apparatus for measuring the thickness of a thin film as claimed in claim 1, wherein said deflecting means is comprised of a rotating mirror and a driving means therefor.
Claim 4
Dependent Claim
61 words
An apparatus for measuring the thickness of a thin film as claimed in claim 1, wherein said projecting optical system includes first lens means for collimating the light beam deflected by said deflecting means and second lens means for focusing the collimated light beam on the thin film, said first and second lens means being arranged on a common optical axis.
Claim 5
Dependent Claim
34 words
An apparatus for measuring the thickness of a thin film as claimed in claim 3, wherein said beam splitter means is arranged on said common optical axis between said first and second lens means.
Claim 6
Dependent Claim
38 words
An apparatus for measuring the thickness of a thin film as claimed in claim 1, wherein said light receiving optical system is comprised of a photo-detector and lens means for focusing the reflected light beams on the photo-detector.
Claim 7
Dependent Claim
39 words
An apparatus for measuring the thickness of a thin film as claimed in claim 1 wherein said angle detecting means is comprised of counting means for counting clock pulses generated in synchronization with the scanning of the light beam.
Claim 8
Dependent Claim
42 words
An apparatus for measuring the thickness of a thin film as claimed in claim 1, further comprising reference beam detecting means for detecting the splitted reference beam in order to check an incident angle of the impinging beam to the thin film.
Claim 9
Dependent Claim
63 words
An apparatus for measuring the thickness of a thin film as claimed in claim 6 wherein said reference beam detecting means includes grid means consisting of a succession of equidistant on an opaque screen and detecting means for detecting individual beams having been passed through respective slits whereby the detected incident angle is checked with use of beams detected by said detecting means.
Claim 10
Independent Claim
115 words
An apparatus for measuring the thickness of a thin film utilizing an interferometric method comprising: light source means for generating a monochromatic light beam; scanning means for scanning the light beam on a thin film in such a manner that an incident angle thereto is continuously varied from α to (- α); first detection means for detecting said incident angle of the light beam; second detection means for detecting an interference pattern caused by light beams reflected from the top and bottom surfaces of the thin film; and calculation means for calculating the thickness of the thin film in accordance with a geometrical optical relation defined between adjacent fringes contained in the detected interference pattern.
Claim 11
Independent Claim
115 words
An apparatus for measuring the thickness of a thin film utilizing an interferometric method comprising: light source means for generating a monochromatic light beam; scanning means for scanning the light beam on a thin film in such a manner that an incident angle thereto is continuously varied from α to (- α); first detection means for detecting said incident angle of the light beam; second detection means for detecting an interference pattern caused by light beams reflected from the top and bottom surfaces of the thin film; and calculation means for calculating the thickness of the thin film in accordance with a geometrical optical relation defined between adjacent fringes contained in the detected interference pattern.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.