US 7,499,183 B2
Method of measuring sub-micron trench structures
Alexei Maznev, Natick, Mass. (US)
Assigned to Advanced Metrology Systems, LLC, Natick, Mass. (US)
Appl. No. 10/561,467
PCT Filed Jun. 23, 2004, PCT No. PCT/IB2004/050985
§ 371(c)(1), (2), (4) Date Dec. 20, 2005,
PCT Pub. No. WO2004/113883, PCT Pub. Date Dec. 29, 2004.
Claims priority of provisional application 60/558071, filed on Mar. 31, 2004.
Claims priority of provisional application 60/482099, filed on Jun. 24, 2003.
Prior Publication US 2008/0123080 A1, May 29, 2008
Int. Cl. G01B 11/24 (2006.01); G01B 11/30 (2006.01)
U.S. Cl. 356—601  [356/600; 356/604] 17 Claims
OG exemplary drawing
 
1. A method for measuring an unfilled patterned structure (3), the pattern comprising features each having a width dimension, the method comprising:
irradiating the unfilled patterned structure (3) with a spatially periodic laser intensity pattern in order to excite surface acoustic waves having a wavelength larger than the feature width dimensions;
diffracting a probe laser beam (6) off the generated surface acoustic waves to form a signal beam;
detecting the signal beam as a function of time to generate a signal waveform;
determining a surface acoustic wave phase velocity from the signal waveform; and
determining at least one property of the patterned structure based on the effect of the surface profile of the unfilled patterned structure on the surface acoustic wave phase velocity.