Browse Prior Art Database

Mask Defect Burst Counter

IP.com Disclosure Number: IPCOM000074799D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Fromer, M: AUTHOR

Abstract

Automatic scanning of photolithographic masks for defects is performed to determine the distribution, as well as the total number of defects on a given unit. This burst counter provides the addition of defect burst counting to scanner displays to give an additional parameter by which a go-no-go acceptability decision is made.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 76% of the total text.

Page 1 of 2

Mask Defect Burst Counter

Automatic scanning of photolithographic masks for defects is performed to determine the distribution, as well as the total number of defects on a given unit. This burst counter provides the addition of defect burst counting to scanner displays to give an additional parameter by which a go-no-go acceptability decision is made.

Defect scanners usually scan one line at a time to generate an electrical signal when intercepting a defect. In this arrangement, a mask defect scanning detector system generates an input at 1 which is provided to an integrator 2 and a burst persistence detector 3. Integrator 2 sums the area under the signal- versus-time curve and supplies this integral to a peak detector and memory 4. Detector 3 and peak detector and memory 4 are set at a threshold level by 5. Burst persistence detector 3 is a short term integrator: If the thresholds of peak detector and memory 4 and burst persistence detector 3 are satisfied, an output is provided from AND 6. Driver pulses are provided by 7 to burst counter 8. The displayed count at 9 is advanced one unit of burst for each count. Counter 8 also provides an automatic reset pulse after each count through feedback connection
10. This reset pulse empties the memory of peak detector and memory 4. A remote reset for counter 8 is provided at 11.

In this arrangement, burst counter 8 has a persistence control which acts to either ignore nonbursts or register a potential burst. If a defect...