Patent
Intensity spatial filter having non-uniformly spaced filter elements
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TLDR
In this paper, a spatial filtering system for inspecting integrated circuit photomasks, and the like, employs a spatial filter comprising a matrix-like array of opaque regions on a transparent field.Abstract:
A spatial filtering system for inspecting integrated circuit photomasks, and the like. The system employs a spatial filter comprising a matrix-like array of opaque regions on a transparent field. Unlike prior art systems where the region-to-region spacing of the filter is uniform, in the instant invention the region-to-region spacing steadily increases from the centermost element outward according to a precise mathematical formula.read more
Citations
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Patent
Production of high performance optical spatial filters
TL;DR: In this article, high performance optical spatial filters are produced photographically with an apparatus that directs a coherent beam of light through or off a subject and into a lens, focusing the diffracted and/or reflected light to define a Fourier transform of the subject information.
Patent
Method and apparatus for high-throughput inspection of large flat patterned media using dynamically programmable optical spatial filtering
TL;DR: In this paper, programmable optical Fourier filtering in the focal plane of a telecentric lens system is used to directly identify physical phenomena indicative of non-periodic defects in planar objects.
Patent
Method for exposure-mask inspection and recording medium on which a program for searching for portions to be measured is recorded
Koji Hashimoto,Shigeki Nojima +1 more
TL;DR: In this article, an exposure mask inspecting method for use in manufacturing semiconductor devices is presented, which calculates the gradients of a correlation curve of a variation in critical dimension of an exposure masks and a variation of critical dimensions of a resist.
Patent
Inspection system for detecting defects in regular patterns
Peter D. Southgate,John P Beltz +1 more
TL;DR: In this paper, a camera, having a photoelectric sensor therein, is mechanically moved to permit the sensor to scan and detect the elements of a pattern, and the system includes circuitry for processing the output of the sensor, including portions for quantizing the sensor output signal, for storing the quantized signal of a portion of a scan, for determining element period from the quanitized signal and for controlling the output output of storage portion at times related to element period.
Patent
Apparatus for detecting the defects of the mask pattern using spatial filtering
Masana Minami,Hidekazu Sekizawa +1 more
TL;DR: In this article, two kinds of light sources, one of which emits a coherent light and the other of which emit incoherent light, are provided, and a spatial filter, having a plurality of arms which extend in predetermined directions from the center thereof, is provided on the focal plane of the transform lens.
References
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Patent
Photomask inspection by spatial filtering
TL;DR: In this article, an optical spatial filtering technique for detecting hole-type defects and excess spot defects in photomasks used in making microcircuits is described, where an approximate form factor intensity filter provides suppression of the regularly shaped mask features.
Patent
Pattern defect sensing using error free blocking spacial filter
TL;DR: In this article, a monochromatic collimated light was used to detect defects in microcircuit patterns by illuminating the pattern with monochrome collimated illumination and an optical filter was placed at the output side of the lens to block the optical frequency components corresponding to the defect-free specimen.
Patent
Photomask regeneration by intensity spatial filtering
TL;DR: In this article, an intensity-type spatial filtering technique is employed to generate a corrected replica of a two-dimensional photomask or other pattern containing an array of regularly spaced elements which exhibit nonperiodic errors.