Piecewise alignment modeling method

Patent metadata

Field	Value
Publication number	US-10133193-B2
Application number	US-201715644284-A
Country	US
Kind code	B2
Filing date	Jul 7, 2017
Priority date	Jul 19, 2016
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

Embodiments disclosed herein generally relate to adjusting exposure parameters of a substrate in response to an overlay error. The method includes partitioning the substrate into one or more sections. Each section corresponds to an image projection system. A total overlay error of a first layer deposited on the substrate is determined. For each section, a sectional overlay error is calculated. For each overlap area, in which two or more sections overlap, an average overlay error is calculated. The exposure parameters are adjusted in response to the total overlay error.

First claim

What is claimed is:

1. A method of adjusting exposure parameters of a substrate in response to an overlay error, comprising:
partitioning the substrate into a plurality of sections, each section corresponding to an image projection system;
determining a total overlay error of a first layer deposited on the substrate, comprising:
for each section, calculating a sectional overlay error; and
for each overlap area in which two or more sections overlap, calculating an average overlay error; and

adjusting exposure parameters in response to the total overlay error.

2. The method of claim 1 , wherein for each section, calculating a sectional overlay error, comprises:
scanning a top surface of the first layer; and
measuring an amount of distortion in the respective section using a trend line.

3. The method of claim 2 , wherein adjusting exposure parameters in response to the total overlay error, comprises:
shifting each coordinate in the section based on the calculated sectional overlay error.

4. The method of claim 1 , wherein for each overlap area in which two or more section overlap, calculating an average overlay error, comprises:
scanning a top surface of the first layer in a first section extending into the overlap area;
scanning the top surface of the first layer in a second section extending into the overlap area;
calculating a first sectional overlay error for the first section by measuring a first amount of distortion using a first trend line;
calculating a second sectional overlay error for the second section by measuring a second amount of distortion using a second trend line; and
averaging the sectional overlay error and the second sectional overlay error.

5. The method of claim 4 , wherein adjusting exposure parameters in response to the total overlay error, comprises:
shifting each coordinate in the overlap area based on the average overlay error.

6. The method of claim 1 , wherein partitioning the substrate into a plurality of sections, each section corresponding to an image projection system, comprises:
determining an origin for each section; and
using the origin for each section to determine a center for each section.

7. The method of claim 1 , wherein a point is in an overlap area provided that the point is both an element of a first section and a second section.

8. A computer system for adjusting exposure parameters of a substrate in response to a total overlay error, comprising:
a processor; and
a memory storing instructions that, when executed by the processor, cause the computer system to:
partition the substrate into a plurality of sections, each section corresponding to an image projection system;
determine the total overlay error of a first layer deposited on the substrate, comprising:
for each section, calculating a sectional overlay error; and
for each overlap area in which two or more sections overlap, calculating an average overlay error; and

adjusting adjust exposure parameters in response to the total overlay error.

9. The computer system of claim 8 , wherein for each section, calculating a sectional overlay error, comprises:
scanning a top surface of the first layer; and
measuring an amount of distortion in the respective section using a trend line.

10. The computer system of claim 9 , wherein adjusting exposure parameters in response to the total overlay error, comprises:
shifting each coordinate in the section based on the calculated sectional overlay error.

11. The computer system of claim 8 , wherein for each overlap area in which two or more section overlap, calculating an average overlay error, comprises:
scanning a top surface of the first layer in a first section extending into the overlap area;
scanning the top surface of the first layer in a second section extending into the overlap area;
calculating a first sectional overlay error for the first section by measuring a first amount of distortion using a first trend line;
calculating a second sectional overlay error for the second section by measuring a second amount of distortion using a second trend line; and
averaging the sectional overlay error and the second sectional overlay error.

12. The computer system of claim 11 , wherein adjusting exposure parameters in response to the total overlay error, comprises:
shifting each coordinate in the overlap area based on the average overlay error.

13. The computer system of claim 8 , wherein partitioning the substrate into a plurality of sections, each section corresponding to an image projection system, comprises:
determining an origin for each section; and
using the origin for each section to determine a center for each section.

14. The computer system of claim 8 , wherein a point is in an overlap area provided that the point is both an element of a first section and a second section.

15. A non-transitory computer-readable medium storing instructions that, when executed by a processer, cause a computer system to adjust exposure parameters of a substrate in response to an overlay error, by performing the steps of:
partitioning the substrate into a plurality of sections, each section corresponding to an image projection system;
determining a total overlay error of a first layer deposited on the substrate, comprising:
for each section, calculating a sectional overlay error; and
for each overlap area in which two or more sections overlap, calculating an average overlay error; and

adjusting exposure parameters in response to the total overlay error.

16. The non-transitory computer-readable medium of claim 15 , wherein for each section, calculating a sectional overlay error, comprises:
scanning a top surface of the first layer; and
measuring an amount of distortion in the respective section using a trend line.

17. The non-transitory computer-readable medium of claim 16 , wherein adjusting exposure parameters in response to the total overlay error, comprises:
shifting each coordinate in the section based on the calculated sectional overlay error.

18. The non-transitory computer-readable medium of claim 15 , wherein for each overlap area in which two or more section overlap, calculating an average overlay error, comprises:
scanning a top surface of the first layer in a first section extending into the overlap area;
scanning the top surface of the first layer in a second section extending into the overlap area;
calculating a first sectional overlay error for the first section by measuring a first amount of distortion using a first trend line;
calculating a second sectional overlay error for the second section by measuring a second amount of distortion using a second trend line; and
averaging the sectional overlay error and the second sectional overlay error.

19. The non-transitory computer-readable medium of claim 18 , wherein adjusting exposure parameters in response to the total overlay error, comprises:
shifting each coordinate in the overlap area based on the average overlay error.

20. The non-transitory computer-readable medium of claim 15 , wherein partitioning the substrate into a plurality of sections, each section corresponding to an image projection system, comprises:
determining an origin for each section; and
using the origin for each section to determine a center for each section.

Assignees

• Applied Materials Inc

Inventors

• Coskun Tamer
• Jeong Hwan J

Classifications

• G03F7/70633 Primary

  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

• G03F7/706835

  Metrology information management or control · CPC title

• G03F7/705

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title

• G03F7/70516

  Calibration of components of the microlithographic apparatus, e.g. light sources, addressable masks or detectors · CPC title

• G03F7/70425

  Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning · CPC title