Substrate placement in immersion lithography

• US 8,441,617 B2
• Filed: 11/03/2011
• Issued: 05/14/2013
• Est. Priority Date: 12/10/2004
• Status: Expired due to Fees

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Hoogendam, Christiaan Alexander, Nijmeijer, Gerrit Johannes, Cuperus, Minne, Van Eijck, Petrus Anton Willem Cornelia Maria
• Primary Examiner(s): NGUYEN, HUNG
• Application Number:
  US13/288,714
• Publication Number:
  US 20120050740A1
• Time in Patent Office: 558 Days
• Field of Search: 355/52, 355/53, 355 72- 76, 356399-401, 250/548, 378/34, 378/35
• US Class Current: 355/72
• 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 loading a substrate in a depression of a chuck, the method comprising:

loading the substrate onto a substrate handler;

determining an offset of a center of the substrate with respect to a center of the depression;

shifting a position of the substrate by an offset to correct for the offset of a center of the substrate with respect to the center of the depression 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

placing the substrate substantially centered into the depression.

2. The method according to claim 1, wherein the shifting comprises

moving the substrate handler above the depression,

translating the substrate so there is substantially zero offset between a substrate edge and an edge of the depression.

3. The method according to claim 1, comprising calibrating the substrate handler to correct the offset.

4. The method according to claim 3, wherein calibrating the substrate handler comprises taking into account a pre-aligner centering offset.

5. The method according to claim 1, comprising determining a position of the center of the depression.

6. The method according to claim 5, wherein the position of the center of the depression is determined by measuring an edge of the depression.

7. The method according to claim 1, comprising determining a position of the center of the substrate.

8. The method according to claim 1, wherein the substrate is placed into the depression with an upper surface of the substrate being at substantially a same level as an upper surface of the chuck.

9. The method according to claim 1, comprising providing a test substrate.

10. The method according to claim 9, wherein the test substrate is provided with an alignment mark for determining the center of the substrate.

11. The method according to claim 1, wherein the chuck is provided with a reference mark for determining the center of the depression.

12. The method according to claim 1, wherein the chuck is part of a lithographic apparatus.