US 7,321,427 B2
Multiple beam ellipsometer
Martin Ebert, Fremont, Calif. (US); and Li Chen, Fremont, Calif. (US)
Assigned to Tokyo Electron Limited, Tokyo (Japan)
Filed on Oct. 10, 2006, as Appl. No. 11/545,434.
Application 11/545434 is a continuation of application No. 11/256841, filed on Oct. 24, 2005, granted, now 7,136,164.
Application 11/256841 is a continuation of application No. 10/893449, filed on Jul. 16, 2004, granted, now 6,985,228.
Application 10/893449 is a continuation of application No. 10/042592, filed on Jan. 09, 2002, granted, now 6,798,512.
Claims priority of provisional application 60/336437, filed on Nov. 01, 2001.
Claims priority of provisional application 60/311035, filed on Aug. 09, 2001.
Prior Publication US 2007/0030485 A1, Feb. 08, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. G01J 4/00 (2006.01)
U.S. Cl. 356—369  [356/368; 356/364] 10 Claims
OG exemplary drawing
 
1. An ellipsometer for evaluating characteristics of a semiconductor sample comprising:
a broadband light source for generating a polychromatic probe beam;
a first set of optics for selectively directing the probe beam to reflect off the sample at a non-normal angle of incidence and in a first direction;
a second set of optics for selectively directing the probe beam to reflect off the sample at a non-normal angle of incidence and in a second direction different from the first direction;
a detector system for selectively receiving the reflected probe beam from one of the first and second directions, said detector system for determining the change in polarization state of the beam induced by the sample and generating output signals in response thereto; and
a processor for combining the output signals in a regression analysis to evaluate the characteristics of the sample.