Apparatus for inspecting a circuit pattern drawn on a photomask

Boots – shoes – and leggings

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

356394, 356237, 2504911, 2504922, G01N 2132

Patent

active

045596034

ABSTRACT:
A photomask on which a circuit pattern is drawn is placed on an x-y table and is illuminated by a light source. A linear image sensor, on which the circuit pattern is imaged, measures the circuit pattern along the direction substantially perpendicular to a moving direction of the x-y table to generate an analog signal in units of measured positions on the mask. In order to eliminate the need for matching the size of the pixel to be measured with the pixel size of the design pattern data and allow effective detection of a defect smaller than the pixel size, an analog-to-digital converter is arranged to convert the analog signal to multi-level digital data, and a measured point calculation circuit calculates the position of the measured point in units smaller than the pixel size unit in accordance with the position of the x-y table. A reference data calculation circuit is provided to calculate multi-level reference digital data which is to be obtained when the design pattern is measured at a calculated measured point taking sensitivity distribution characteristics (including resolution characteristics of lens) of image sensor elements into consideration. A defect detector compares the measured data with the reference data to detect the presence or absence of defects of the circuit pattern on the photomask.

REFERENCES:
patent: 4218142 (1980-08-01), Kryger et al.
patent: 4390955 (1983-06-01), Arimura
patent: 4392120 (1983-07-01), Mita et al.
patent: 4465350 (1984-08-01), Westerberg
patent: 4475037 (1984-10-01), Vettiger et al.
patent: 4508453 (1985-04-01), Hara et al.
An Automated Mask Inspection System-AMIS-Bruning et al., IEEE Trans. on Electron Devices, vol. ED-22, No. 77, 7/75, pp. 487-495.
Solid State Technology, Kenneth Levy, "Automated Equipment for 100% Inspection of Photomasks", vol. 21, No. 5, pp. 60-66, 71 (May 1978).
Solid State Technology, vol. 21, No. 5, (May 1978), D. B. Novotny et al., "Automated Photomask Inspection", pp. 51-59, 76.
Solid State Technology, vol. 21, No. 6, (Jun. 1978), D. B. Novotny et al, "Automated Photomask Inspection," pp. 59-67.
Reticle Mask Automatic Defect Inspecting Device; D. Awamura (transliterated); Electronic Material; Jun. 1982.
"An Automatic Mask and Reticle Inspection System"; Hal Yang; Proceedings of the Society of Photo-Optical Instrumentation Engineers; Mar. 31, 1982.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Apparatus for inspecting a circuit pattern drawn on a photomask does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Apparatus for inspecting a circuit pattern drawn on a photomask , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for inspecting a circuit pattern drawn on a photomask will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-2177731

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.