US 7,321,431 B2
Method and system for analyzing low-coherence interferometry signals for information about thin film structures
Peter De Groot, Middletown, Conn. (US)
Assigned to Zygo Corporation, Middlefield, Conn. (US)
Filed on May 18, 2006, as Appl. No. 11/437,002.
Claims priority of provisional application 60/682742, filed on May 19, 2005.
Prior Publication US 2006/0262321 A1, Nov. 23, 2006
Int. Cl. G01B 11/06 (2006.01)
U.S. Cl. 356—497  [356/504; 356/511] 46 Claims
OG exemplary drawing
 
1. A method comprising:
providing a scanning interferometry signal produced by a scanning interferometer for a first location of a test object;
providing a model function of the scanning interferometry signal produced by the scanning interferometer, wherein the model function is parametrized by one or more parameter values;
fitting the model function to the scanning interferometry signal for each of a series of shifts in scan position between the model function and the scanning interferometry signal by varying the parameter values; and
determining information about the test object at the first location based on the fitting.