Inspecting method and apparatus for photomask pattern

Details Inspecting method and apparatus for photomask pattern Inspecting method and apparatus for photomask pattern

1984-09-17

1987-05-26

Birmiel, Howard A.

Image analysis

Histogram processing

For setting a threshold

382 21, 382 27, G06K 900

Patent

active

046691235

ABSTRACT:
A method and an apparatus for inspecting a photomask pattern utilizing a vector comparing method. A pair of optical images intended to be compared are taken from the photomask pattern and converted to digital data by optical systems and an amplitude distributor. The digital data have values of black (B), gray (G), or white (W) corresponding to high, middle, and low signal amplitudes. Separated data corresponding to a portion of each of the optical images are sequentially separated from the digital data by data separators. The separated data are shifted by several matrix elements of the separated data by data shifters to provide shifted data. The shifted data of each optical image and separated data are respectively synthesized by data synthesizers to provide two groups of synthesized data. Vectors are generated from the matrices of the groups of synthesized data by vector generators. The vectors are defined to indicate changes from B to W, from B to G, and from G to W, in one of eight latitudinal, longitudinal, and diagonal directions. The number of vectors having the same direction in vectors are respectively summed and compared by a vector comparator which outputs information of a defect on the photomask pattern if there is a difference between the groups for the summation of any vector direction.

REFERENCES:
patent: 3899771 (1975-08-01), Saraga et al.
patent: 4148065 (1979-04-01), Nakagawa et al.
patent: 4490848 (1984-12-01), Beall et al.
patent: 4532650 (1985-07-01), Wihl et al.
IBM Technical Disclosure Bulletin, vol. 25, No. 11b, Apr. 1983, pp. 6080-6081, N.Y., J. C. Harmon, "Angular Features for Character Recognition".

Affiliated with

Also associated with

Rating

Inspecting method and apparatus for photomask pattern does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Inspecting method and apparatus for photomask pattern, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inspecting method and apparatus for photomask pattern will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-708868