Substrate placement in immersion lithography

• US 8,077,291 B2
• Filed: 10/09/2007
• Issued: 12/13/2011
• Est. Priority Date: 12/10/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Hoogendam, Christiaan Alexander, Cuperus, Minne, Nijmeijer, Gerrit Johannes, Van Eijck, Petrus Anton Willern Cornelia Maria
• Primary Examiner(s): NGUYEN, HUNG
• Application Number:
  US11/907,045
• Publication Number:
  US 20080106723A1
• Time in Patent Office: 1,526 Days
• Field of Search: 355/53, 355 72- 76, 356399-401, 250/548, 378/34, 378/35
• US Class Current: 355/77
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01B 11/272 using photoelectric detection means
• 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 7/707 Chucks, e.g. chucking or un-chucking operations or structural details
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/70775 Position control, e.g. interferometers or encoders for determining the stage position
• CPC Class Codes: G03F 9/7011 Pre-exposure scan; original with original holder alignment; Prealignment, i.e. workpiece with workpiece holder

Abstract

A method for determining an offset between a center of a substrate and a center of a depression in a chuck includes providing a test substrate to the depression, the test substrate having a dimension smaller than a dimension of the depression, measuring a position of an alignment mark of the test substrate while in the depression, and determining the offset between the center of the substrate and the center of the depression from the position of the alignment mark.

Claims

1. A method for determining an offset between a center of a substrate and a center of a depression in a chuck, comprising:

loading the substrate on a pin of the chuck and moving the substrate by translating the pin in a first direction until the substrate reaches an opening of the depression in the chuck;

determining to what extent the substrate should be translated in a plane substantially perpendicular to the first direction to allow the substrate to enter inside the depression without colliding with a surface of the chuck or an edge of the depression in the chuck; and

determining the offset of the substrate relative to the depression from determination of the translation in the plane.

2. The method according to claim 1, wherein determining to what extent the substrate should be translated comprises translating the substrate, in the plane on the pin relative to the chuck, translating the chuck, in the plane, relative to the substrate or the pin, or both, until a footprint of the substrate would fit into the depression.

3. The method according to claim 1, wherein loading the substrate on a pin of the chuck is performed with a substrate handler.

4. The method according to claim 1, further comprising calibrating the substrate handler to take into account the offset.

5. The method according to claim 4, wherein calibrating the substrate handler includes shifting positioning of substrates by of the substrate handler by an amount to correct for the offset so that a subsequently positioned substrate is substantially centered inside the depression.

6. The method according to claim 4, wherein calibrating the substrate handler includes correcting for substrate positioning so that the gap of a subsequently positioned substrate is equally wide inside the depression.

7. The method according to claim 1, wherein determining to what extent the substrate should be translated comprises measuring a position of an alignment mark of the substrate relative to a reference mark of the chuck or vice versa.

8. A method for determining an offset between a center of a substrate and a center of a depression in a table, comprising:

moving the substrate in a first direction toward the table until the substrate reaches a position adjacent an opening of the depression in the table;

determining to what extent the substrate should be translated in a plane substantially perpendicular to the first direction to allow the substrate to enter inside the depression without contacting an upper surface of the table or an edge of the depression in the table; and

determining the offset of the substrate relative to the depression from determination of the translation in the plane.

9. The method according to claim 8, comprising loading the substrate on a pin of the table.

10. The method according to claim 8, wherein determining to what extent the substrate should be translated comprises translating the substrate, in the plane relative to the table, translating the table, in the plane, relative to the substrate, or both, until a footprint of the substrate would fit into the depression.

11. The method according to claim 8, wherein, prior to the moving, the method comprises loading the substrate on a pin of the table using a substrate handler.

12. The method according to claim 11, further comprising calibrating the substrate handler to take into account the offset.

13. The method according to claim 12, wherein calibrating the substrate handler includes shifting positioning of substrates by of the substrate handler by an amount to correct for the offset so that a subsequently positioned substrate is substantially centered inside the depression.

14. The method according to claim 12, wherein calibrating the substrate handler includes correcting for substrate positioning so that a gap of a subsequently positioned substrate is equally wide inside the depression.