Dual resolution combined laser spot scanning and area imaging inspection

United States Patent [w]

Almogy

US006122046A [ii] Patent Number: [45] Date of Patent:

6,122,046 Sep. 19,2000

[54] DUAL RESOLUTION COMBINED LASER SPOT SCANNING AND AREA IMAGING INSPECTION

[75] Inventor: Gilad Almogy, Givatayim, Israel

[73] Assignee: Applied Materials, Inc., Santa Clara, Calif.

[21] Appl. No.: 09/165,992 [22] Filed: Oct. 2, 1998

[51] Int. CI.7 G01N 21/88

[52] U.S. CI 356/237.2; 356/371

[58] Field of Search 356/371, 237.2,

356/237.3, 237.4, 239.7, 239.8

[56] References Cited

U.S. PATENT DOCUMENTS

4,290,698 9/1981 Milana 356/371

4,465,371 8/1984 Pernick 356/237.2

4,731,855 3/1988 Suda et al 382/8

4,740,708 4/1988 Batchelder 356/237.3

5,105,092 4/1992 Natsubori et al 356/237.2

5,125,741 6/1992 Okada et al 356/237.2

5,572,598 11/1996 Wihl et al 382/144

5,737,085 4/1998 Zollars et al 356/237.2

5,805,278 9/1998 Danko 356/237

FOREIGN PATENT DOCUMENTS

96/39619 12/1996 WIPO G01N 21/00

OTHER PUBLICATIONS

Joseph W. Goodman, Introduction to Fourier
Optics2ndedition, McGraw-Hill (1996), chapter 5.
G. Dickerson and R. Wallace, "In-line Wafer Inspection
Using 100 Megapixel Per Second Digital Image Processing
Technology,"5P/E vol. 1464 Integrated Circuit Metrology,
Inspection, and Process Control, (1992), pp. 584-595.
David Alumot et al., "Dual Sensor Technology for High-
Speed Detection of 0.1 Micron Defects, "Proceedings of the
SPIE, vol. 1926, Integrated Circuit Metrology, Inspection,
and Process Control VII, (1993), pp. 1-12.

Primary Examiner—Richard A. Rosenberger

Attorney, Agent, or Firm—Sughrue, Mion, Zinn, Macpeak

& Seas, PLLC

[57] ABSTRACT

An optical inspection system for inspecting a substrate includes a light detector, a light source, a deflection system, an objective lens and an optical system. The light source produces an illuminating beam directed along a path to the substrate. The deflection system scans the illuminating beam on a scan line of the substrate. The objective lens focuses the illuminating beam on the substrate and coliects light reflected therefrom. The collected beam is angularly wider than the illuminating beam. The optical system directs the collected light beam along a path at least partially different than the path of the illuminating beam and focuses the collected beam on the light detector. In one embodiment, the system additionally includes at least one dark field detector for collecting light deflected from the substrate.

18 Claims, 7 Drawing Sheets