| US 7,532,318 B2 | ||
| Wafer edge inspection | ||
| Steven W. Meeks, Fremont, Calif. (US); Rusmin Kudinar, Fremont, Calif. (US); William R. Wheeler, Saratoga, Calif. (US); Hung Phi Nguyen, Santa Clara, Calif. (US); Vamsi Velidandla, San Jose, Calif. (US); Anoop Somanchi, Fremont, Calif. (US); and Ronny Soetarman, Fremont, Calif. (US) | ||
| Assigned to KLA-Tencor Corporation, San Jose, Calif. (US) | ||
| Filed on Nov. 16, 2006, as Appl. No. 11/560,477. | ||
| Application 11/560477 is a continuation of application No. 11/365221, filed on Mar. 01, 2006, granted, now 7,161,669. | ||
| Application 11/365221 is a continuation in part of application No. 11/196540, filed on Aug. 03, 2005, granted, now 7,161,668. | ||
| Application 11/196540 is a continuation in part of application No. 11/123913, filed on May 06, 2005, granted, now 7,161,667. | ||
| Prior Publication US 2007/0127016 A1, Jun. 07, 2007 | ||
| Int. Cl. G01N 21/00 (2006.01) | ||
| U.S. Cl. 356—237.2 [356/237.1] | 29 Claims |
| 1. A system to rotate an optical head around an edge of a wafer, comprising:
a radial motor to move the optical head in a first radial direction across a surface of the wafer and also in a second radial
direction opposite the first radial directional across an opposing bottom of the water;
a rotational motor to move the optical head around the edge of the wafer such that the optical head first faces the surface
of the wafer and then rotates around the edge to face the bottom of the wafer; and
a sensor to measure a distance between the optical head and an underlying one of the surface, edge, and bottom of the wafer;
wherein the radial motor and the rotational motor cooperate to maintain a constant distance between the optical head and the
underlying one of the surface, edge, and bottom of the wafer as the optical head moves around the edge of the wafer.
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