System and Method for Measurement of Alignment

• US 20200133144A1
• Filed: 05/18/2018
• Published: 04/30/2020
• Est. Priority Date: 06/08/2017
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: SCHMITT-WEAVER, Emil Peter, BHATTACHARYYA, Kaustuve, QUEENS, Rene Marinus Gerardus Johan, HENKE, Wolfgang Helmut, TEL, Wim Tjibbo, LINSCHOTEN, Theodorus Franeiscus Adrianus Maria
• Granted Patent: US 11,249,404 B2
• Time in Patent Office: Days
• CPC Class Codes: G03F 9/7003 Alignment type or strategy, e.g. leveling, global alignment
• CPC Class Codes: G03F 9/7026 Focusing
• CPC Class Codes: G03F 9/7034 Leveling
• CPC Class Codes: G03F 9/7084 Position of mark on substrate, i.e. position in (x, y, z) of mark, e.g. buried or resist covered mark, mark on rearside, at the substrate edge, in the circuit area, latent image mark, marks in plural levels
• CPC Class Codes: G03F 9/7088 Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection
• CPC Class Codes: G03F 9/7092 Signal processing

Abstract

A system comprises a topography measurement system configured to determine a respective height for each of a plurality of locations on a substrate; and a processor configured to: determine a height map for the substrate based on the determined heights for the plurality of locations; and determine at least one alignment parameter for the substrate by comparing the height map and a reference height map, wherein the reference height map comprises or represents heights for a plurality of locations on a reference substrate portion.

Claims

1-16. -16. (canceled)

17. A system comprising:

a topography measurement system configured to determine a respective height for each of a plurality of locations on a substrate; and

a processor configured to;

determine a height map for the substrate based on the determined heights for the plurality of locations; and

determine at least one alignment parameter for the substrate by comparing the height map and a reference height map, wherein the reference height map comprises or represents heights for a plurality of locations on a reference substrate portion.

18. The system of claim 17, wherein the determining of the at least one alignment parameter for the substrate by comparing the height map and the reference height map comprises:

determining based on the height map and the reference height map a position for at least one portion of the substrate that corresponds to the reference substrate portion; and

determining the at least one alignment parameter using the determined position for the, or each, portion of the substrate.

19. The system of claim 17, wherein the, or each, portion of the substrate comprises at least one of:

at least one circuit or part of a circuit, at least one target portion, at least one topography measurement mark.

20. The system of claim 17, wherein the determined alignment parameter may comprise a location of a center of gravity for the, or each, portion of the substrate.

21. The system of claim 17, wherein the height map comprises heights in z, and the at least one alignment parameter comprises at least one of:

a relative position in x, a relative position in y, a rotation in the x-y plane.

22. The system of claim 17, wherein the processor is further configured to process the height map by removing the global shape of the wafer and other non-intrafield properties.

23. The system of claim 17, wherein the reference height map comprises a signature representing an alignment of centers of gravity of target portions.

24. The system of claim 17, wherein the processor or a further processor is configured to determine a focus adjustment for a lithographic apparatus based on the determined heights.

25. The system of claim 24, wherein the topography measurement system comprises a first sensor and a second sensor;

the first sensor is configured to determine the respective height for each of the plurality of locations on the substrate, from which the height map is determined;

the second sensor is configured to determine further heights for the substrate; and

the processor or a further processor is configured to determine a focus adjustment for a lithographic apparatus based on the determined further heights.

26. The system of claim 17, the system further comprising an alignment system configured to determine a respective position of each of a plurality of alignment marks on the substrate;

wherein the processor is further configured to determine at least one further alignment parameter based on the determined positions of the alignment marks.

27. A method comprising:

determining a respective height for each of a plurality of locations on a substrate;

determining a height map for the substrate based on the determined heights for the plurality of locations; and

determining at least one alignment parameter for the substrate by comparing the height map and a reference height map, wherein the reference height map comprises or represents heights for a plurality of locations on a reference substrate portion.

28. A lithographic apparatus comprising:

an illumination system configured to condition a radiation beam;

a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;

a substrate table constructed to hold a substrate; and

a projection system configured to project the patterned radiation beam onto a target portion of the substrate,

wherein the lithographic apparatus further comprises;

a topography measurement system configured to determine a respective height for each of a plurality of locations on a substrate; and

a processor configured to;

determine a height map for the substrate based on the determined heights for the plurality of locations; and

determine at least one alignment parameter for the substrate by comparing the height map and a reference height map, wherein the reference height map comprises or represents heights for a plurality of locations on a reference substrate portion.

29. The lithographic apparatus of claim 28, further comprising an alignment system configured to determine a respective position of each of a plurality of alignment marks on the substrate.

30. A system comprising:

a topography measurement system configured to determine a respective height for each of a plurality of locations on a substrate;

an alignment system configured to determine a respective position of each of a plurality of alignment marks on the substrate; and

a processor configured to;

determine a height map for the substrate based on the determined heights for the plurality of locations;

using the determined positions of the plurality of alignment marks, determine a location of each of a plurality of target portions of the substrate, each target portion comprising substantially the same features; and

determine a reference height map by processing sections of the height map corresponding to each of the target portions.

31. The system of claim 30, wherein the processing of the sections of the height map comprises averaging the heights of the sections of the height map.

32. A method comprising:

determining a respective height for each of a plurality of locations on a substrate;

determining a respective position of each of a plurality of alignment marks on the substrate;

determining a height map for the substrate based on the determined heights for the plurality of locations;

using the determined positions of the plurality of alignment marks, determining a location of each of a plurality of target portions of the substrate, each target portion comprising substantially the same features; and

determining a reference height map by processing sections of the height map corresponding to each of the target portions.