Alignment mark detector for electron beam lithography

Details Alignment mark detector for electron beam lithography Alignment mark detector for electron beam lithography

1985-09-20

1989-02-07

Lall, Parshotam S.

Boots, shoes, and leggings

2504911, 364819, G01B 1500, G01N 2300

Patent

active

048036447

ABSTRACT:
A hardware system is disclosed for detecting alignment marks on a substrate in connection with electron beam lithography. The system is considerably faster than prior software approaches. A scanning signal derived from backscattered electrons as the beam scans the substrate is stored and updated in a set of shift registers as scanning proceeds. The signals in the scanning shift registers are compared with a predetermined reference signal, corresponding to the expected scanning signal when the beam traverses an edge of an alignment mark, stored in another set of shift registers. A correlation is obtained between the scanning and reference signals by multiplying the values of the corresponding cells in the scanning and reference registers, and accumulating and weighting the result. The locations of the maximum positive and negative correlations, and hence the locations of the opposed edges of the alignment mark, are obtained by means of a timing mechanism coordinated with the scanning.

REFERENCES:
patent: 3898617 (1975-08-01), Kashioka et al.
patent: 3901814 (1975-08-01), Davis et al.
patent: 3924113 (1975-12-01), Gill et al.
patent: 4056730 (1977-11-01), Davis et al.
patent: 4109029 (1978-08-01), Ozdemir et al.
patent: 4123661 (1978-10-01), Wolf et al.
patent: 4242662 (1980-12-01), Tsujiyama et al.
patent: 4267580 (1981-05-01), Bond et al.
patent: 4295204 (1981-11-01), Sunstein
patent: 4297676 (1981-11-01), Moriya et al.
patent: 4327292 (1982-04-01), Wang et al.
patent: 4334241 (1982-06-01), Kashioka et al.
patent: 4347580 (1982-08-01), Bond
patent: 4370554 (1983-01-01), Bohlen et al.
patent: 4385238 (1983-05-01), Westerberg et al.
patent: 4407933 (1983-10-01), Fraser et al.
patent: 4412301 (1983-10-01), Strubeck
patent: 4547864 (1985-10-01), Kawabata
patent: 4558225 (1985-12-01), Gotou et al.
patent: 4636968 (1987-01-01), Gotou et al.
Hahmann et al., ZBA10 Electron-Beam Exposure System Further Improved, Jena. Rev. (Germany), JR 2, 1980, pp. 65-66.
Ozdemir et al., Computer Controlled Scanning Electron Microscope System for High Resolution Microelectronic Pattern Fabrication, IEEE Transactions on Electron Devices, vol. ED-19, No. 5, May 1972, pp. 624-628.
Davis et al., Automatic Registration in an Electron-Beam Lithographic System, Solid State Technology, Aug. 1978, pp. 61-67.
E. Argyle, "Techniques for Edge Detection", Proceedings of the IEEE, Feb. 1971, pp. 285-287.
D. Cumming, "A High Speed, Noise Tolerant Edge Detection Algorithm Using a Low Bandwidth Signal Chain for E-Beam Registration", (no publication data presently available).
D. Stephani, "Monte-Carlo Calculations of Backscattered Electrons at Registration Marks", J. Vac. Sci. Technol., 16(6), Nov./Dec. 1979, pp. 1739-1742.

Affiliated with

Also associated with

Rating

Alignment mark detector for electron beam lithography does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Alignment mark detector for electron beam lithography, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alignment mark detector for electron beam lithography will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1089153