Method and apparatus for angular-resolved spectroscopic lithography characterization

• US 8,760,662 B2
• Filed: 08/27/2013
• Issued: 06/24/2014
• Est. Priority Date: 08/16/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Den Boef, Arie Jeffrey, 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, Cdric Dsir, Van Kraaij, Markus Gerardus Martinus Maria
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): Cook, Jonathon
• Application Number:
  US14/011,663
• Publication Number:
  US 20140055788A1
• Time in Patent Office: 301 Days
• Field of Search: 356/456, 356/494, 356/511, 356/521
• US Class Current: 356/456
• CPC Class Codes: G01N 21/8806 Specially adapted optical and illumination features
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/70633 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 Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G03F 9/7034 Leveling

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.

Claims

1. A method, comprising:

directing a radiation beam from a radiation source toward a pattern formed on a substrate;

splitting the radiation beam into two polarized beam components;

detecting an angle-resolved spectrum of the two polarized beam components reflected from a surface of the substrate; and

measuring a property of the substrate by measuring asymmetries between intensities of corresponding diffraction orders diffracted from the pattern in the reflected angle-resolved spectrum,

wherein the asymmetries are related to an extent of an overlay between two misaligned periodic structures.

2. The method of claim 1, further comprising:

measuring at least one of;

an intensity of transverse magnetic and transverse electric polarized light; and

a phase difference between the transverse magnetic and the transverse electric polarized light.

3. The method of claim 1, further comprising:

measuring, in the pupil plane of a lens, another property of the reflected angle-resolved spectrum at a plurality of wavelengths substantially simultaneously.

4. The method of claim 1, further comprising:

directing a portion a portion of the radiation beam for separate measurement.

5. A method, comprising:

directing a radiation beam from a radiation source toward a pattern formed on a substrate;

detecting an angle-resolved spectrum of the radiation source reflected from a surface of the substrate;

measuring a property of the substrate by measuring, at a plurality of wavelengths of the radiation beam, asymmetries between intensities of corresponding diffraction orders diffracted from the pattern in the reflected angle-resolved spectrum; and

measuring in the pupil plane of a lens, another property of the reflected angle-resolved spectrum at the plurality of wavelengths substantially simultaneously;

wherein the asymmetries are related to an extent of an overlay between two misaligned periodic structures.

6. The method of claim 5, further comprising:

measuring at least one of;

an intensity of transverse magnetic and transverse electric polarized light; and

a phase difference between the transverse magnetic and the transverse electric polarized light.

7. The method of claim 5, further comprising:

directing a portion of the radiation beam for separate measurement.