EP0035720A1
Expired / Lapsed
EP
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Apparatus for inspecting an object by light
Assignee: Toshiba Corp
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Filing: 1981-02-27
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Granted: —
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Expires: 2001-02-27
Abstract
Abstract Disclosed is an apparatus for determining the average size of fundamental patterns (23) contained in a given region of an object (11) to be inspected, which includes Fouriertransform means for producing output data corresponding to a Fourier transform pattern image of the given region of the object, and processor means for processing the output data to provide the actual pattern size information. The Fourier transform means includes a Fourier converter (13-15) for providing the output data corresponding to Fourier transform patterns (200,201). The processor means includes an extractor (16,17) coupled to the Fouriertransform means (13-15) for extracting a specific data (in) representing the order n of spatial frequency component (e.g. 200) from the output data, the magnitude of the order n component changing with variation (e.g.ΔaH) of the size of patterns (23); and a data processor (19 or 49) coupled to the extractor (16,17) for determining the average size of patterns (23) in the given region according to the specific data (In) and providing the actual pattern size information indicating the average size of the patterns.
Inventors
- 👤 Akito Iwamoto
- 👤 Hidekazu Sekizawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 09:47
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
170 words
An apparatus for inspecting an object comprising Fourier transform means for forming a Fourier transform pattern of the object, and processor means for determining the size of the pattern contained in the object from the Fourier transform pattern, CHARACTERIZED IN THAT said Fourier transform means includes a Fourier transformer (13-15 or 40 - 48) for providing an output data corresponding to a Fourier-transform pattern (200, 201), image of a given region of the object containing regularly arrayed fundamental patterns, AND THAT said processor means includes an extractor (16, 17, 49) coupled to said Fourier transformer (13-15, 40-48) for extracting a specific data (In) representing a spatial frequency component (e.g. 200) of the order n from the output data, the magnitude of the order n component changing with variation (e.g. Δa H ) of the size of fundamental patterns (23); and first means (19 or 49) coupled to said extractor (16, 17) for determining the average size of fundamental patterns (23) on the given region according to the specific data (In).
Claim 2
Independent Claim
170 words
An apparatus for inspecting an object comprising Fourier transform means for forming a Fourier transform pattern of the object, and processor means for determining the size of the pattern contained in the object from the Fourier transform pattern, CHARACTERIZED IN THAT said Fourier transform means includes a Fourier transformer (13-15 or 40 - 48) for providing an output data corresponding to a Fourier-transform pattern (200, 201), image of a given region of the object containing regularly arrayed fundamental patterns, AND THAT said processor means includes an extractor (16, 17, 49) coupled to said Fourier transformer (13-15, 40-48) for extracting a specific data (In) representing a spatial frequency component (e.g. 200) of the order n from the output data, the magnitude of the order n component changing with variation (e.g. Δa H ) of the size of fundamental patterns (23); and first means (19 or 49) coupled to said extractor (16, 17) for determining the average size of fundamental patterns (23) on the given region according to the specific data (In).
Claim 3
Dependent Claim
56 words
An apparatus according to claim 1, wherein said Fourier transformer (13-15) forms an image of the Fourier transform pattern optically, and the extractor (16, 17) extracts the order n diffracted light component (200) of the image, intensity of the order n diffracted light component being corresponding to the magnitude of the order n spatial frequency component.
Claim 4
Dependent Claim
55 words
An apparatus according to claim 2, wherein said Fourier transformer (13-15) includes means (13, 14) for illuminating the given region of the object (11) with a coherent light, and a lens system (15, 15A) for producing a Fourier transform pattern image containing spatial frequency components (200, 201) of the illuminated region of the object (11).
Claim 5
Independent Claim
30 words
An apparatus according to any on of claism 1 to 3, wherein said first means (19, or 49) calculates the specific data (In) to provide the actual pattern size information.
Claim 6
Independent Claim
30 words
An apparatus according to any on of claism 1 to 3, wherein said first means (19, or 49) calculates the specific data (In) to provide the actual pattern size information.
Claim 7
Independent Claim
56 words
An apparatus according to any one of claims 2 to 4, wherein the extractor (16, 17) includes an opening or spatial filter (16) provided on a specific place where the image' of the order n diffracted light component is formed, and a photoelectric converter (17) for providing an electric signal corresponding to the specific data (In).
Claim 8
Dependent Claim
24 words
An apparatus according to claim 5, wherein said opening (16) is elongate in the direction of rotation of the order n diffracted light spots.
Claim 9
Dependent Claim
62 words
An apparatus according to claim 1, wherein the Fourier transformer (40-48) includes means (40, 41) for illuminating the given region of the object (42) with an incoherent light, and image sensor means (43-48) for sensing an optical image of the illuminated region of the object (42) and producing output data repre. cnting a Fourier transform pattern corresponding to the sensed optical image.
Claim 10
Independent Claim
73 words
An apparatus according to any one of claims 1 to 7, wherein said processor means (40-49) includes memory means (49 2 ) for storing a data table representing the relation (e.g. Fig. 6) between the specific data (In) and the variation (Δa H ) of the size of patterns (23), and means (49 3 ) for searching the data table to provide the actual patter size information according to the specific dat (In).
Claim 11
Independent Claim
247 words
An apparatus according to any one of claims 1 to 6, wherein said first means (19) includes: a pulse generator (30) for generating a clock pu se (φ0), a first load pulse (φ1), a second load pulse (φ2) and a third load pulse (φ3); a first register (35) receiving the first load pulse (φ1) for storing a first data (ID) corresponding to the specific data (In); a first data memory (33) receiving the first data (ID) for memorizing a specific relation (e.g. Fig. 6) between magnitude of the order n comonent (In) and variation (Δa H ) of the size of patterns (23), and providing a second data (I D2 ) from a specific address thereof in accordance with the address designation by the first data (I D ); a second register (36) receiving the second load pulse (φ2) for storing the second data (I D2 ) indicating the variation (Δa H ) of the order n component (In); an X -counter (31) for counting the clock pulse (φ0) and providing an X-axis data (CX); a Y-counter (32) for counting a carry out of the X-counter (31) and providing a Y-axis data (CY); and a second memory (34) receiving the third load pulse (φ3), the X - and Y-axis data (CX, CY) and the second data (ID 2 ), for storing the variation (Δa H ) of each Y-axis of the object (11) and providing a display data (DD) representing the average variation value of each Y-axis.
Claim 12
Independent Claim
67 words
An apparatus according to any one of claims 1 to 9, wherein the order n spatial frequency component is so selected that the rate of change or the differential coefficient (ΔI n /Δa H or ΔI n /Δζ) of the magnitude of the order n component (ΔI n ) with respect to the variation (Δa H or Δζ) of the size of patterns (23) is substantially maximum.
Claim 13
Dependent Claim
39 words
An apparatus according to claim 10, wherein the selected order of the spatial frequency component (e.g. 200) is in the neighborhood of a point (e.g. A2) where an envelope (100-102) of the spatial frequency components has an extreme value.
Claim 14
Independent Claim
118 words
An apparatus according to any one of claims 1 to 11, characterized by further comprising: level sensor means (70, 72, 74) coupled to said processor means (16, 17, 19, 49), for providing a color signal (R, G, B MOD) when a processed a data (DD) corresponding to the magnitude of the specific data (In) falls into a predetermined reference level (L l , L 2 ); color decoder means (76) receiving the color signal, for decoding the color signal and providing a color display signal (CS); and color display means (78) receiving the color display signal (CS), for displaying two-dimensional color images corresponding to the average size of patterns (23) in different colors for different average size ranges.
Claim 15
Independent Claim
36 words
An apparatus according to any one of claims 1 to 12, wherein the Fourier transform means further includes means (15A) for enlarging the Fourier transform pattern image in order to improve the resolution of the apparatus.
References Cited (Backward Citations)
US3954337A
Cited
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