US4926489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reticle inspection system
Assignee: KLA Corp
•
Filing: 1987-10-05
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Granted: 1990-05-15
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Expires: 2007-10-05
Abstract
Abstract An automatic inspection system including an illuminator for illuminating a reticle or photomask to be inspected, while optically projecting a magnified image of the reticle or photomask onto a plurality of detector elements. A carriage assembly moves the object at a constant velocity to allow the detector elements to sequentially view the entire surface to be inspected. The detector elements are responsive to the intensity of light incident thereupon and are periodically scanned to obtain a two-dimensional measured representation of the object. A database adaptor formulates a two-dimensional representation from the design database description corresponding to the scanned object simultaneously and in synchronism with the scanning of the photomask or reticle. The measured and database adapted representation of the scanned object are input to a signal processor for alignment and defect detection. While the representations are shifted through a memory, an alignment circuit dynamically measures and corrects for misalignment between the representations, so that a defect detector can effectively compare the representations for defects. Additional correction of misalignment between the representations is obtained by modulating the size of the measured representation as detected by the detector elements. At the operator's option, a second measured image of a multi-cell reticle or photomask may be used for comparison as a substitute for the database representation.
Inventors
- 👤 Donald L. Danielson
- 👤 Mark J. Wihl
- 👤 David A. Joseph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:33
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95607; G03; G03F; G03F1/00; G03F1/68; G03F1/82; G03F1/84; G06; G06T; G06T7/00; G06T7/0002; G06T7/0004; G06T7/001; G06T7/30; G01N2021/95676; G06T2207/00; G06T2207/30; G06T2207/30108; G06T2207/30148; G06V; G06V2201/00; G06V2201/06
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
262 words
Optical inspection apparatus for scanning a patterned object and comparing it to information contained in an electronic data base, comprising: optical scanning means responsive to a first timing control signal and operative to scan the patterned object and to develop a first data signal including a sampled and quantitized electronic representation of the patterned object; data base means responsive to a second timing control signal and operative to generate a second data signal corresponding to a design database description of the patterned object scanning by said scanning means, said second data signal having a variable time relationship to said first data signal; data alignment means for comparing said first data signal to said second data signal and for developing an excess alignment signal which corresponds to any misalignment of said second data signal exceeding a predetermined limit, and for adjusting said time relationship between said first data signal and said second data signal to provided aligned first and second data signals which are time coincident with each other; timing control means responsive to said excess alignment signal and operative to develop said first and second timing control signals, said first and second timing control signals being used to adjust the relative output data signal rates of said optical scanning means and said data base means for the purpose of maintaining the alignment of said first and second data signals within predetermined limits; and defect detector means for comparing said aligned first data signal and said aligned second data signal and for developing defect data signals corresponding to differences therebetween having predetermined characteristics.
Claim 2
Dependent Claim
262 words
Optical inspection apparatus for scanning a patterned object and comparing it to information contained in an electronic data base, comprising: optical scanning means responsive to a first timing control signal and operative to scan the patterned object and to develop a first data signal including a sampled and quantitized electronic representation of the patterned object; data base means responsive to a second timing control signal and operative to generate a second data signal corresponding to a design database description of the patterned object scanning by said scanning means, said second data signal having a variable time relationship to said first data signal; data alignment means for comparing said first data signal to said second data signal and for developing an excess alignment signal which corresponds to any misalignment of said second data signal exceeding a predetermined limit, and for adjusting said time relationship between said first data signal and said second data signal to provided aligned first and second data signals which are time coincident with each other; timing control means responsive to said excess alignment signal and operative to develop said first and second timing control signals, said first and second timing control signals being used to adjust the relative output data signal rates of said optical scanning means and said data base means for the purpose of maintaining the alignment of said first and second data signals within predetermined limits; and defect detector means for comparing said aligned first data signal and said aligned second data signal and for developing defect data signals corresponding to differences therebetween having predetermined characteristics.
Claim 3
Dependent Claim
78 words
Optical inspection apparatus as recited in claim 1 wherein said database means includes: electronic storage means for storing said design database description; pattern memory means for receiving a selected portion of said design database description stored in said storage means; pattern generating means for converting said selected portion into bit mapped data; bit map memory means for storing said bit mapped data; and scan converter means for converting the stored bit mapped data into said second data signal.
Claim 4
Dependent Claim
26 words
Optical inspection apparatus as recited in claim 2 wherein said pattern memory means is a double-buffered memory and said bit map memory is a double-buffered memory.
Claim 5
Dependent Claim
71 words
Optical inspection apparatus as recited in claim 3 wherein said data alignment means includes: an alignment memory for receiving and storing said first and second data signals and for responding to alignment error correction signals to develop said aligned first and second data signals; and alignment error detection means for comparing portions of said first and second data signals stored in said alignment memory and developing said alignment error correction signals.
Claim 6
Dependent Claim
100 words
Optical inspection apparatus as recited in claim 4 wherein said alignment memory includes: a memory address control means responsive to said alignment error correction signal and operative to develop first and second data select signals; a left pixel memory for storing a quantity of said first data signal and responsive to said first data select signal to output a portion thereof as said aligned first data signal; and a right pixel memory for storing a quantity of said second data signal and responsive to said second data select signal to output a portion thereof as said aligned second data signal.
Claim 7
Dependent Claim
66 words
Optical inspection apparatus as recited in claim 4 wherein said alignment error detection means includes: two-dimensional phase detection means which compares portions of said first and second data signals and develops error signals corresponding to the instantaneous magnitude and direction of misalignment therebetween; and alignment processor means responsive to said error signals and operative to generate said alignment error correction signals and said excess alignment signal.
Claim 8
Dependent Claim
62 words
Optical inspection apparatus as recited in claim 6 wherein said two-dimensional phase detection means includes: X-direction error detection means responsive to portions of said first and second data signals and operative to generate X-components of said error signals; and Y-direction error detection means responsive to portions of said first and second data signals and operative to generate Y-components of said error signals.
Claim 9
Dependent Claim
46 words
Optical inspection apparatus as recited in claim 6 wherein said alignment error detection means further includes goodness logic means responsive to portions of said first and second data signals and operative to generate goodness signals qualifying said error signals for input to said alignment processor means.
Claim 10
Dependent Claim
49 words
Optical inspection apparatus as recited in claim 4 wherein said timing control means includes a controllable phase locked oscillator means responsive to a scan position signal developed by said optical sensing means and to said excess alignment signal and operative to generate said first and second timing control signals.
Claim 11
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 9 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 12
Dependent Claim
64 words
Optical inspection apparatus as recited in claim 9 wherein said timing control means further includes a scale compensation means for generating a scale compensation signal, and wherein said phase locked oscillator means is further responsive to said scale compensation signal and operative to modify at least one of said first and second timing signals to compensate for known scale errors in the patterned object.
Claim 13
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 11 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 14
Dependent Claim
49 words
Optical inspection apparatus as recited in claim 3 wherein said timing control means includes a controllable phase locked oscillator means responsive to a scan position signal developed by said optical sensing means and to said excess alignment signal and operative to generate said first and second timing control signals.
Claim 15
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 13 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 16
Dependent Claim
64 words
Optical inspection apparatus as recited in claim 13 wherein said timing control means further includes a scale compensation means for generating a scale compensation signal, and wherein said phase locked oscillator means is further responsive to said scale compensation signal and operative to modify at least one of said first and second timing signals to compensate for known scale errors in the patterned object.
Claim 17
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 15 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 18
Dependent Claim
71 words
Optical inspection apparatus as recited in claim 2 wherein said data alignment means includes: an alignment memory for receiving and storing said first and second data signals and for responding to alignment error correction signals to develop said aligned first and second data signals; and alignment error detection means for comparing portions of said first and second data signals stored in said alignment memory and developing said alignment error correction signals.
Claim 19
Dependent Claim
100 words
Optical inspection apparatus as recited in claim 17 wherein said alignment memory includes: a memory address control means responsive to said alignment error correction signal and operative to develop first and second data select signals; a left pixel memory for storing a quantity of said first data signal and responsive to said first data select signal to output a portion thereof as said aligned first data signal; and a right pixel memory for storing a quantity of said second data signal and responsive to said second data select signal to output a portion thereof as said aligned second data signal.
Claim 20
Dependent Claim
66 words
Optical inspection apparatus as recited in claim 17 wherein said alignment error detection means includes: two-dimensional phase detection means which compares portions of said first and second data signals and develops error signals corresponding to the instantaneous magnitude and direction of misalignment therebetween; and alignment processor means responsive to said error signals and operative to generate said alignment error correction signals and said excess alignment signal.
Claim 21
Dependent Claim
62 words
Optical inspection apparatus as recited in claim 19 wherein said two-dimensional phase detection means includes: x-direction error detection means responsive to portions of said first and second data signals and operative to generate X-components of said error signals; and y-direction error detection means responsive to portions of said first and second data signals and operative to generate Y-components of said error signals.
Claim 22
Dependent Claim
46 words
Optical inspection apparatus as recited in claim 19 wherein said alignment error detection means further includes goodness logic means responsive to portions of said first and second data signals and operative to generate goodness signals qualifying said error signals for input to said alignment processor means.
Claim 23
Dependent Claim
49 words
Optical inspection apparatus as recited in claim 17 wherein said timing control means includes a controllable phase locked oscillator means responsive to a scan position signal developed by said optical sensing means and to said excess alignment signal and operative to generate said first and second timing control signals.
Claim 24
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 22 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 25
Dependent Claim
64 words
Optical inspection apparatus as recited in claim 22 wherein said timing control means further includes a scale compensation means for generating a scale compensation signal, and wherein said phase locked oscillator means is further responsive to said scale compensation signal and operative to modify at least one of said first and second timing signals to compensate for known scale errors in the patterned object.
Claim 26
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 24 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 27
Dependent Claim
49 words
Optical inspection apparatus as recited in claim 2 wherein said timing control means includes a controllable phase locked oscillator means responsive to a scan position signal developed by said optical sensing means and to said excess alignment signal and operative to generate said first and second timing control signals.
Claim 28
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 26 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 29
Dependent Claim
64 words
Optical inspection apparatus as recited in claim 26 wherein said timing control means further includes a scale compensation means for generating a scale compensation signal, and wherein said phase locked oscillator means is further responsive to said scale compensation signal and operative to modify at least one of said first and second timing signals to compensate for known scale errors in the patterned object.
Claim 30
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 28 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 31
Dependent Claim
71 words
Optical inspection apparatus as recited in claim 1 wherein said data alignment means includes: an alignment memory for receiving and storing said first and second data signals and for responding to alignment error correction signals to develop said aligned first and second data signals; and alignment error detection means for comparing portions of said first and second data signals stored in said alignment memory and developing said alignment error corresponding signals.
Claim 32
Dependent Claim
100 words
Optical inspection apparatus as recited in claim 30 wherein said alignment memory includes: a memory address control means responsive to said alignment error correction signal and operative to develop first and second data select signals; a left pixel memory for storing a quantity of said first data signal and responsive to said first data select signal to output a portion thereof as said aligned first data signal; and a right pixel memory for storing a quantity of said second data signal and responsive to said second data select signal to output a portion thereof as said aligned second data signal.
Claim 33
Dependent Claim
67 words
Optical inspection apparatus as recited in claim 30 wherein said alignment error detection means includes: two-dimensional phase detection means which compares portions of said first and second data signals and develops error signals corresponding to the phase instantaneous magnitude and direction of misalignment therebetween; and alignment processor means responsive to said error signals and operative to generate said alignment error correction signals and said excess alignment signal.
Claim 34
Dependent Claim
62 words
Optical inspection apparatus as recited in claim 32 wherein said two-dimensional phase detection means includes: X-direction error detection means responsive to portions of said first and second data signals and operative to generate X-components of said error signals; and Y-direction error detection means responsive to portions of said first and second data signals and operative to generate Y-components of said error signals.
Claim 35
Dependent Claim
46 words
Optical inspection apparatus as recited in claim 32 wherein said alignment error detection means further includes goodness logic means responsive to portions of said first and second data signals and operative to generate goodness signals qualifying said error signals for input to said alignment processor means.
Claim 36
Dependent Claim
49 words
Optical inspection apparatus as recited in claim 30 wherein said timing control means includes a controllable phase locked oscillator means responsive to a scan position signal developed by said optical sensing means and to said excess alignment signal and operative to generate said first and second timing control signals.
Claim 37
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 35 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 38
Dependent Claim
64 words
Optical inspection apparatus as recited in claim 35 wherein said timing control means further includes a scale compensation means for generating a scale compensation signal, and wherein said phase locked oscillator means is further responsive to said scale compensation signal and operative to modify at least one of said first and second timing signals to compensate for known scale errors in the patterned object.
Claim 39
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 37 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 40
Dependent Claim
49 words
Optical inspection apparatus as recited in claim 1 wherein said timing control means includes a controllable phase locked oscillator means responsive to a scan position signal developing by said optical sensing means and to said excess alignment signal and operative to generate said first and second timing control signals.
Claim 41
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 39 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
Claim 42
Dependent Claim
64 words
Optical inspection apparatus as recited in claim 39 wherein said timing control means further includes a scale compensation means for generating a scale compensation signal, and wherein said phase locked oscillator means is further responsive to said scale compensation signal and operative to modify at least one of said first and second timing signals to compensate for known scale errors in the patterned object.
Claim 43
Dependent Claim
95 words
Optical inspection apparatus as recited in claim 41 wherein said timing control means is further responsive to an input pixel size select signal developed by said optical scanning means and operative to modify certain characteristics of said first and second timing control signals so as to cause said optical scanning means to scan at a speed such that it has a resolution corresponding to said input pixel size select signal, and operative to cause said database means to generate said second data signal at a resolution likewise corresponding to said input pixel size select signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-14 | 1993-11-13 | 1994-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-14 | 1997-11-13 | 1998-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-14 | 2001-11-13 | 2002-05-15 | $7700.00 | Window Closed / Lapsed |