EP0225651A2
Expired / Lapsed
EP
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Method of and apparatus for detecting pattern defects
Assignee: Dainippon Screen Manufacturing Co Ltd
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Filing: 1986-12-12
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Granted: —
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Expires: 2006-12-12
Abstract
Abstract The periphery of an area of a master pattern (M 0 ) is expanded by a required number of pixels to define a plurality of master pattern areas two-dimensionally misregistered pixel by pixel, for performing pattern comparison of the respective master pattern areas (M₁₁ ∼ M₇₇) with an area of an object pattern (P). The object pattern (P) is deemed defective when all of the comparisons indicate pattern mismatches. The pattern is deemed not defective when at least one comparison indicates a pattern match. Thus, even if an inspected object includes misregistration errors, pattern defects can be detected with high accuracy.
Inventors
- 👤 Hiroyuki Dainippon Screen Mfg.Co. Ltd. Onishi
- 👤 Tetsuo Dainippon Screen Mfg.Co. Ltd. Sano
- 👤 Tetsuo Dainippon Screen Mfg. Co. Ltd. Hoki
- 👤 Eiji Dainippon Screen Mfg.Co. Ltd. Kodama
- 👤 Hisayuki Dainippon Screen Mfg.Co. Ltd. Tsujinaka
- 👤 Ryuji Dainippon Screen Mfg.Co. Ltd. Kitakado
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 19:43
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95607; G06; G06T; G06T7/00; G06T7/0002; G06T7/0004; G06T7/001; G06V; G06V10/00; G06V10/70; G06V10/74; G06V10/75; G06V10/751; G06V10/7515; G03; G03F; G03F1/00; G03F1/68; G03F1/82; G03F1/84; G06T2207/00; G06T2207/30; G06T2207/30108; G06T2207/30141; G06T2207/30148
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
246 words
A method of detecting pattern defects by comparing a two-dimensional object pattern formed by digitized picture signals obtained sequentially along scanning lines with a digitized two-dimensional master pattern per unit area of a prescribed size, said method comprising the steps of: defining a reference area by expanding the periphery of an area of said master pattern to positionally correspond to an area of said object pattern by a required number of pixels for setting a plurality of master pattern areas two-dimensionally misregistered pixel-by-pixel in prescribed amounts over said expanding area; and comparing the digitized signals of said master pattern areas with the digitized signals of said area of said object pattern corresponding to said master pattern area perform defect detection by: (a) while scanning defect inspection windows in the size of a plurality of pixels over an entire area of said pattern areas, comparing one of said plurality of master pattern areas with said object pattern area to determine that said patterns are mismatched when all digitized signals of corresponding pixels of both said patterns included in said windows are mismatched in any scanning position; (b) determining that said object pattern is defective when said object pattern area is determined to be mismatched with respect to one of said plurality of master pattern areas; and (c) determining that said object pattern is not defective when said object pattern area is determined not to be mismatched with respect to at least one of said master pattern areas.
Claim 2
Independent Claim
246 words
A method of detecting pattern defects by comparing a two-dimensional object pattern formed by digitized picture signals obtained sequentially along scanning lines with a digitized two-dimensional master pattern per unit area of a prescribed size, said method comprising the steps of: defining a reference area by expanding the periphery of an area of said master pattern to positionally correspond to an area of said object pattern by a required number of pixels for setting a plurality of master pattern areas two-dimensionally misregistered pixel-by-pixel in prescribed amounts over said expanding area; and comparing the digitized signals of said master pattern areas with the digitized signals of said area of said object pattern corresponding to said master pattern area perform defect detection by: (a) while scanning defect inspection windows in the size of a plurality of pixels over an entire area of said pattern areas, comparing one of said plurality of master pattern areas with said object pattern area to determine that said patterns are mismatched when all digitized signals of corresponding pixels of both said patterns included in said windows are mismatched in any scanning position; (b) determining that said object pattern is defective when said object pattern area is determined to be mismatched with respect to one of said plurality of master pattern areas; and (c) determining that said object pattern is not defective when said object pattern area is determined not to be mismatched with respect to at least one of said master pattern areas.
Claim 3
Dependent Claim
50 words
A method of detecting pattern defects in accordance with claim 1, wherein the step of comparing said area of said two-dimensional object pattern with said area of said two-dimensional master pattern is performed in parallel with a plurality of areas of a prescribed size arranged in the main scanning direction.
Claim 4
Independent Claim
298 words
An apparatus for detecting pattern defects by comparing a two-dimensional object pattern with a two-dimensional master pattern per unit area of a prescribed size, with apparatus comprising: means for inputting digitized signals of said object pattern in a sequential manner; means for reading digitized signals of said master pattern in a sequential manner from a memory synchronously with said object pattern; first extraction means for extracting digitized signals in a specific area of said object pattern in a sequential manner along the scanning direction synchronously with said object pattern; second extraction means for defining an expanded area by expanding the periphery of a specific area of said master pattern to positionally correspond to said specific area whose digitized signals are extracted by said first extraction means by a required number of pixels and extracting digitized signals in a plurality of specific areas two-dimensionally misregistered pixel by pixel in prescribed amounts over said expanded area in a sequential manner along the scanning direction respectively; a plurality of comparison/decision means for sequentially comparing said digitized signals in said specific area of said object pattern extracted by said first extraction means with said digitized signals in said specific areas of said master pattern extracted by said second extraction means in prescribed size areas of both said patterns to hold mismatch results when all of said digitized signals of corresponding pixels in said specific areas are mismatched in at least one portion in any scanning position; and first decision means for determining that said prescribed size area of said object pattern is defective when all of said comparison/decision means hold pattern mismatch decision results and determining that said prescribed size area of said object pattern is not defective when at least one of said comparison/decision means holds no pattern mismatch decision result.
Claim 5
Independent Claim
298 words
An apparatus for detecting pattern defects by comparing a two-dimensional object pattern with a two-dimensional master pattern per unit area of a prescribed size, with apparatus comprising: means for inputting digitized signals of said object pattern in a sequential manner; means for reading digitized signals of said master pattern in a sequential manner from a memory synchronously with said object pattern; first extraction means for extracting digitized signals in a specific area of said object pattern in a sequential manner along the scanning direction synchronously with said object pattern; second extraction means for defining an expanded area by expanding the periphery of a specific area of said master pattern to positionally correspond to said specific area whose digitized signals are extracted by said first extraction means by a required number of pixels and extracting digitized signals in a plurality of specific areas two-dimensionally misregistered pixel by pixel in prescribed amounts over said expanded area in a sequential manner along the scanning direction respectively; a plurality of comparison/decision means for sequentially comparing said digitized signals in said specific area of said object pattern extracted by said first extraction means with said digitized signals in said specific areas of said master pattern extracted by said second extraction means in prescribed size areas of both said patterns to hold mismatch results when all of said digitized signals of corresponding pixels in said specific areas are mismatched in at least one portion in any scanning position; and first decision means for determining that said prescribed size area of said object pattern is defective when all of said comparison/decision means hold pattern mismatch decision results and determining that said prescribed size area of said object pattern is not defective when at least one of said comparison/decision means holds no pattern mismatch decision result.
Claim 6
Dependent Claim
52 words
An apparatus for detecting pattern defects in accordance with claim 3, wherein said comparison/decision means includes: means for comparing said area of said two-dimensional object pattern with said areas of said two-dimensional master pattern in parallel with respect to a plurality of areas of prescribed size arranged in the main scanning direction.
Claim 7
Dependent Claim
116 words
An apparatus for detecting pattern defects in accordance with claim 3, wherein said comparison/decision means includes: comparison means for comparing match and mismatch of digitized signals in said specific area of said object pattern extracted by said first extraction means with said digitized signals in said specific areas of said master pattern extracted by said second extraction means per corresponding pixels; second decision means for determining that said patterns are mismatched when all of the results of comparison of said corresponding pixels by said comparison means are mismatched; and holding means for holding pattern mismatch results in a pattern scanning interval when there is at least one pattern mismatch decision result by said second decision means.
Claim 8
Dependent Claim
90 words
An apparatus for detecting pattern defects in accordance with claim 5, wherein said comparison/decision means include: means for making mismatch decisions on the bases of the results of comparisons which extract only specific pixels corresponding to various defective patterns from the results of comparison of all pixels in said specific areas by said comparison means respectively, and means for selecting any one decision result within the results of decision of said various defective pattens made by said means for making mismatch decisions to make the same outputted to holding means.
Claim 9
Dependent Claim
134 words
An apparatus for detecting pattern defects in accordance with claim 5, wherein each said comparison means is formed by a plurality of exclusive OR circuits receiving digitized signals of respective pixels included in said specific area of said object patterns in each one input terminal as well as digitized signals of respective pixels included in said specific areas of said master pattern in other input terminals, each said decision means is formed by a first AND circuit receiving all of output signals from said plurality of exclusive OR circuits, and each said holding means is formed by OR circuit receiving output signals from said first AND circuit in one input terminal and D-type flip-flop receiving output signals from said OR circuit and supplying output signals thereof to other input terminal of said OR circuit.
Claim 10
Dependent Claim
63 words
An apparatus for detecting pattern defects in accordance with claim 3, wherein said first extraction means includes a plurality of first shift registers for delaying said digitized signals of said object pattern sequentially by one scanning operation, and said second extraction means includes a plurality of second shift registers for sequentially delaying said digitized signals of said master pattern by one scanning operation.
Claim 11
Dependent Claim
31 words
An apparatus for detecting pattern defects in accordance with claim 3, wherein said first decision means includes a second AND circuit receiving output signals from respective ones of said comparison/decision means.
References Cited (Backward Citations)
No citation records indexed.
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