Lithographic apparatus, substrate table, and method for enhancing substrate release properties

• US 8,792,085 B2
• Filed: 08/13/2010
• Issued: 07/29/2014
• Est. Priority Date: 12/27/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Puyt, Michiel, Bleeker, Arno Jan, Compen, Rene Theodorus Petrus, Fischer, Rudolf Hartmut
• Primary Examiner(s): WHITESELL GORDON, STEVEN H
• Application Number:
  US12/856,106
• Publication Number:
  US 20100296073A1
• Time in Patent Office: 1,446 Days
• Field of Search: 355/53, 355/72, 355/75
• US Class Current: 355/72
• CPC Class Codes: G03F 7/707 Chucks, e.g. chucking or un-chucking operations or structural details
• CPC Class Codes: G03F 7/70708 being electrostatic; Electrostatically deformable vacuum chucks
• CPC Class Codes: H01L 21/6875 characterised by a plurality of individual support members, e.g. support posts or protrusions
• CPC Class Codes: H01L 21/68757 characterised by a coating or a hardness or a material

Abstract

A lithographic apparatus includes an illumination system constructed and arranged to condition a radiation beam, and a support constructed and arranged to support a patterning device. The patterning device is capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam. The apparatus also includes a substrate table constructed and arranged to hold a substrate, and a projection system constructed and arranged to project the patterned radiation beam onto a target portion of the substrate. The substrate table includes a chuck having a plurality of protrusions constructed and arranged to support corresponding parts of a bottom surface of a wafer. The top surface of at least one of the protrusions includes a plurality of elements that define a reduced contact area between the substrate and the top surface of the protrusion.

Claims

1. A substrate table for supporting a substrate comprising a first and second surface, the substrate table comprising:

a chuck configured to clamp the substrate;

protrusions comprising a first material coupled to the chuck to support the first surface of the substrate, wherein a first surface of at least one of the protrusions faces the first surface of the substrate; and

a plurality of micro elements coupled to the first surface of each of the protrusions, wherein;

each of the plurality of micro elements comprises a second material, the second material being different from the first material and having, a property of elasticity; and

each of the plurality of micro elements comprises a cross-section having a non-cylindrical form or the plurality of micro elements comprises a cross-sectional pattern, the cross-sectional pattern comprising alternating local maxima and minima regions, the local maxima regions being in contact with the first surface of the substrate.

2. A substrate table according to claim 1, wherein the protrusions are burls.

3. A substrate table according to claim 1, wherein the micro elements comprise chemically substantially non-reacting ends.

4. A substrate table according to claim 1, wherein the micro elements are configured as a monolayer.

5. A substrate table according to claim 4, wherein the monolayer comprises bucky balls, glass pearls, polymeric molecules, or nano-tubes, or any combination thereof.

6. A substrate table according to claim 4, wherein the monolayer comprises organic, aromatic, a-polar, or fluorinated molecules, or any combination thereof

7. A substrate table according to claim 4, wherein the monolayer comprises oxide, nitride, or Teflon molecules, or any combination thereof.

8. A substrate table according to claim 1, wherein the substrate table forms a part of a lithographic apparatus.

9. A substrate table according to claim 1, wherein the substrate table forms a part of an implanter or an etching device.

10. A method for enhancing substrate release properties of a protrusion in a substrate table that is configured to support a substrate comprising a first and second surface, the method comprising:

coupling a plurality of protrusions to a chuck of the substrate table, wherein each of the plurality of protrusion comprises a first material; and

disposing a plurality of micro elements at a first surface of each of the plurality of protrusions of the substrate table, wherein;

each of the plurality of micro elements comprises a second material, the second material , being different from the first, material and, having a property of elasticity; and

each of the plurality of micro elements are formed having a non-cylindrical cross-section or the plurality of micro elements are formed having a cross-sectional pattern comprising alternating local maxima and minima regions, the local maxima regions being in contact with the first surface of the substrate.

11. A method according to claim 10, wherein the disposing comprises:

forming a monolayer of the plurality of micro elements at the first surface of at least one of the plurality of protrusions;

applying a plasma enhanced chemical vapor deposition (PE-CVD) or filter high current arc (F-HCA) process to generate the monolayer on the first surface of at least one of the plurality of protrusions.

12. A method according to claim 10, further comprising:

depositing or growing a monolayer to form the plurality of micro elements on the first surface of at least one of the plurality of protrusions.

13. A method according to claim 10, further comprising:

applying a wet solution comprising organic molecules to the first surface of at least one of the plurality of protrusions; and

exposing the wet solution to an UV source or allowing the wet solution to chemically react with surface bonds to form a monolayer of the plurality of micro elements on the first surface of the at least one of the plurality of protrusions.

14. A method according to claim 10, further comprising:

locally machining with a laser to form a defined pattern of the plurality of micro elements on the first surface of at least one of the plurality of protrusions.

15. A method according to claim 14, wherein the locally machining with the laser forms a defined pattern with height differences of an order of nanometers or an order of tens of nanometers.

16. A method according to claim 14, wherein the locally machining with the laser forms a defined pattern having convex or concave surfaces that are spherical, circular or elliptic.

17. A method according to claim 14, wherein the locally machining with the laser forms a defined pattern having edge structures.