| US 7,599,076 B2 | ||
| Method for optically detecting height of a specimen and charged particle beam apparatus using the same | ||
| Keiya Saito, Hiratsuka (Japan); Masahiro Watanabe, Yokohama (Japan); and Yasuhiro Yoshitake, Yokohama (Japan) | ||
| Assigned to Hitachi High-Technologies Corporation, Tokyo (Japan) | ||
| Filed on Nov. 02, 2006, as Appl. No. 11/591,563. | ||
| Claims priority of application No. 2005-327190 (JP), filed on Nov. 11, 2005. | ||
| Prior Publication US 2007/0109557 A1, May 17, 2007 | ||
| Int. Cl. G01B 11/28 (2006.01) | ||
| U.S. Cl. 356—630 | 9 Claims |
| 1. A method for optically detecting a height of a specimen surface, comprising steps of:
using a two-dimensional slit to project a two-dimensional symmetrical light pattern to an object from a position diagonally
above said object;
forming an image of the projected two-dimensional symmetrical light pattern projected on said object;
detecting said image of the two-dimensional light pattern by a two-dimensional area sensor and converting said detected image
into an electrical signal;
selecting electrical signal having a symmetrical wave pattern from the electrical signal converted from the detected image;
and
detecting a height of said object by using information obtained from the selected electrical signal.
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