Metrology by reconstruction

• US 10,437,158 B2
• Filed: 12/16/2016
• Issued: 10/08/2019
• Est. Priority Date: 12/31/2015
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Socha, Robert John
• Primary Examiner(s): Rahman, Md M
• Application Number:
  US16/060,192
• Publication Number:
  US 20180364588A1
• Time in Patent Office: 1,026 Days
• Field of Search: 356625
• CPC Class Codes: G03F 7/70141 Illumination system adjustment, e.g. adjustments during exposure or alignment during assembly of illumination system
• CPC Class Codes: G03F 7/70158 Diffractive optical elements
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness

Abstract

Disclosed herein is a method comprising: obtaining a plurality of measurement results from a pattern on a substrate respectively using a plurality of substrate measurement recipes, the substrate processed by a lithography process; reconstruct, using a computer, the pattern using the plurality of measurement results, to obtain a reconstructed pattern.

Claims

1. A method comprising:

obtaining a plurality of measurement results from a pattern on a substrate respectively using a plurality of substrate measurement recipes performed by a metrology apparatus that illuminates the pattern with radiation, the substrate processed by a lithography process; and

reconstructing, using a computer, the pattern using the plurality of measurement results, to obtain a reconstructed pattern;

wherein each of the plurality of substrate measurement recipes corresponds to one of a plurality of diffraction-based optical measurements to the pattern defined by a plurality of parameterized models respectively, each measurement result is a diffraction image obtained by using one corresponding substrate measurement recipe, and a reconstruction algorithm depends on the plurality of parameterized models.

2. The method of claim 1, wherein reconstructing the pattern is by using a Algebraic Reconstruction Technique, Radon transform, or projection-slice theorem.

3. The method of claim 1, wherein reconstructing the pattern does not use an entirety of each of the plurality of measurement results.

4. The method of claim 1, wherein at least two of the plurality of substrate measurement recipes differ in intensity distribution at a pupil plane of a metrology tool used in obtaining the measurement results.

5. The method of claim 1, wherein at least two of the plurality of substrate measurement recipes differ in a wavelength or a polarization of light used in obtaining the measurement results.

6. The method of claim 1, wherein the pattern has at least one of an asymmetry, a tilted bottom, and a tilted sidewall.

7. The method of claim 1, wherein obtaining a plurality of measurement results comprises illuminating the pattern with ultraviolet light or X-ray.

8. The method of claim 1, further comprising determining an edge placement error or a dimension using the reconstructed pattern.

9. The method of claim 1, further comprising aligning a patterning device to the pattern using the reconstructed pattern.

10. The method of claim 1, further comprising determining alignment between two sub-patterns of the pattern, wherein the two sub-patterns are on different layers of the substrate.

11. The method of claim 1, further comprising determining a true value of a measured characteristic of the pattern, using the reconstructed pattern.

12. The method of claim 1, further comprising determining a systematic error of a measured characteristic of the pattern, using the reconstructed pattern.

13. A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer implementing the method of claim 1.