Inspection device for detecting defects in a periodic pattern on

Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

356347, 359564, G01B 9021

Patent

active

051700638

ABSTRACT:
An inspection device for detecting defects in a periodic pattern on a semiconductor wafer includes a laser oscillator. In the exposure process, light emitted from the laser oscillator is divided into a subject beam and a reference beam. The subject beam is guided to a semiconductor wafer having a periodic pattern thereon by mirrors and a beam expander. The light scattered from the specimen is collected by a lens on a photographic plate. The reference beam is guided to the photographic plate via a second beam expander and another mirror. The intensity of the reference beam is adjusted to a level at which the reference beams interferes on the photographic plate with the light scattered from defects in the periodic pattern and collected by the lens. Thus, a hologram of the defects in the pattern is recorded on the photographic plate. After development, the photographic plate is returned to its original position and used to form a holographic image of the defects with a transmitted regeneration light beam.

REFERENCES:
patent: 4674824 (1987-06-01), Goodman et al.
patent: 4857425 (1989-08-01), Phillips
patent: 4929081 (1990-05-01), Yamamoto et al.
D. L. Cavan et al., "Patterned Wafer Inspection Using Laser Holography And Spatial Frequency Filtering", Journal of Vacuum Science Technology B6 (6), Nov./Dec. 1988, pp. 1934-1939.

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

Inspection device for detecting defects in a periodic pattern on does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Inspection device for detecting defects in a periodic pattern on, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inspection device for detecting defects in a periodic pattern on will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-962448

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