Method and apparatus for angular-resolved spectroscopic lithography characterization

Patent metadata

Field	Value
Publication number	US-10241055-B2
Application number	US-201414264547-A
Country	US
Kind code	B2
Filing date	Apr 29, 2014
Priority date	Aug 16, 2004
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

An apparatus and method to determine a property of a substrate by measuring, in the pupil plane of a high numerical aperture lens, an angle-resolved spectrum as a result of radiation being reflected off the substrate. The property may be angle and wavelength dependent and may include the intensity of TM- and TE-polarized radiation and their relative phase difference.

First claim

What is claimed is:

1. A method, comprising:
directing a radiation beam from a radiation source toward a pattern formed on a substrate;
detecting, in a pupil plane of a lens, an angle-resolved spectrum of the radiation beam reflected from the pattern; and
measuring asymmetries between intensities of corresponding diffraction orders diffracted from the pattern in the reflected angle-resolved spectrum to measure a property of the substrate.

2. The method of claim 1 , wherein the measuring asymmetries comprises measuring at least one of:
an intensity of a transverse magnetic and a transverse electric polarized light, and
a phase difference between the transverse magnetic and the transverse electric polarized light.

3. The method of claim 1 , wherein asymmetries between intensities of corresponding diffraction orders diffracted from the pattern are a property of the reflected angle-resolved spectrum and the measuring a property of the substrate further comprises:
measuring, in the pupil plane of the lens, another property of the reflected angle-resolved spectrum at a plurality of wavelengths substantially simultaneously.

4. The method of claim 3 , wherein the plurality of wavelengths each have a spacing of at least twice a bandwidth of the plurality of wavelengths.

5. The method of claim 1 , further comprising:
providing the radiation beam to a surface of the substrate, the radiation beam having a wavelength of at least 50 nm.

6. The method of claim 1 , wherein the asymmetries are related to an extent of an overlay between two misaligned periodic structures.

7. The method of claim 1 , further comprising:
achieving a pre-defined separation of the reflected angle-resolved spectrum in the pupil plane.

8. The method of claim 1 , further comprising:
using a portion of the radiation beam to measure an intensity of the radiation beam.

9. The method of claim 1 , further comprising:
compensating for fluctuations in an intensity pattern of the reflected radiation beam.

10. The method of claim 1 , further comprising:
limiting, using a pupil stop, a size of a portion of the radiation beam.

11. The method of claim 1 , further comprising:
coupling off a portion of the radiation beam emitted from the radiation source for a separate measurement.

Assignees

• Asml Netherlands Bv

Inventors

• Den Boef Arie Jeffrey Maria
• Bleeker Arno Jan
• Van Dommelen Youri Johannes Laurentius Maria
• Dusa Mircea
• Kiers Antoine Gaston Marie
• Luehrmann Paul Frank
• Pellemans Henricus Petrus Maria
• Van Der Schaar Maurits
• Grouwstra Cedric Desire
• Van Kraaij Markus Gerardus Martinus

Classifications

• G03F9/7034

  Leveling · CPC title

• G01N21/8806 Primary

  Specially adapted optical and illumination features · CPC title

• G03F7/70341 Primary

  Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply (chemical composition of immersion liquids G03F7/2041) · CPC title

• G03F7/70633

  Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching · CPC title

• G03F7/7065

  Defects, e.g. optical inspection of patterned layer for defects · CPC title