Substrate holder and method of manufacturing a substrate holder
An object holder for a lithographic apparatus has a main body having a surface. A plurality of burls to support an object are formed on the surface or in apertures of a thin-film stack. At least one of the burls is formed by laser-sintering. At least one of the burls formed by laser-sintering may be a repair of a damaged burl previously formed by laser-sintering or another method.
1. A holder for use in a lithographic apparatus, the holder comprising:
a main body comprising at least one material selected from: Zerodur ceramic, cordierite, SiC, AlN, SiSiC, ceramic or glass-ceramic;
a plurality of first burls at a first side of the main body and having end surfaces to support an object, wherein the first burls each comprise a first body portion protruding from the main body and a second body portion located further from the main body than the first body portion, wherein the first body portions are made of the same material as the material of the main body and the second body portions comprise a material selected from: diamond, diamond-like carbon, SiC, SiO 2 , TiN, cubic boron nitride, silicon nitride, titanium, titanium carbide, cordierite or aluminum nitride;
a plurality of second burls at a second side of the main body, the second side being opposite of the first side;
a heat transfer element located between the first and second sides of the main body; and
an electric or electrical component on an external surface of the main body at a side other than the first side.
2. The holder according to claim 1 , wherein the main body has a thickness in a range of 1 mm to 50 mm.
3. The holder according to claim 1 , wherein each of the first burls and/or second burls has a height in a range of about 5 μm to about 250 μm.
4. The holder according to claim 1 , wherein a total area of all the burls on one side of the main body is less than 3% of the total surface area of the main body.
5. The holder according to claim 1 , further comprising a heater provided to the main body and configured to control a temperature of the object and/or the main body.
6. The holder according to claim 1 , wherein the first body portions comprise a different material than the second body portions.
7. A lithographic apparatus comprising the holder of claim 1 .
8. A holder for use in a lithographic apparatus, the holder comprising:
a main body;
a recess in or on the main body, the recess having one or more openings therein, the one or more openings configured to exhaust fluid; and
a plurality of burls surrounding the recess and having end surfaces to support an object, wherein the burls each comprise a first body protruding portion and a second body protruding portion located further from the main body than the first body protruding portion, wherein the first body portions comprise a different material than the second body portions and wherein the recess is recessed relative to a surface from which the burls extend.
9. The holder according to claim 8 , further comprising a further recess having a plurality of further openings therein, the further opening configured to exhaust fluid and a plurality of further burls surrounding the further recess and having end surfaces to support the object, wherein the further burls each comprise a first body protruding portion and a second body protruding portion located further from the main body than the first body protruding portion, and the first body portions of the further burls comprise a different material than the second body portions of the further burls.
10. The holder according to claim 8 , wherein the main body comprises an aperture extending all the way through the main body and configured to allow radiation to pass from one side of the main body to an opposite of the main body.
11. The holder according to claim 8 , further comprising a flexible element configured to allow movement of the recess primarily in a plane of the main body across which the object is arranged to be supported.
12. The holder according to claim 8 , wherein the main body is formed of a different material from the burls.
13. The holder according to claim 8 , wherein the second body portions comprise a material selected from: diamond, diamond-like carbon, SiC, SiO 2 , TiN, cubic boron nitride, silicon nitride, titanium, titanium carbide, cordierite or aluminum nitride.
14. A lithographic apparatus comprising the substrate holder of claim 8 .
15. A holder for use in a lithographic apparatus, the holder comprising:
a main body;
a support member supported by a flexible element, that is separate from the support member, on the main body, the support member having one or more openings, the one or more openings configured to exhaust fluid; and
a plurality of burls surrounding the one or more openings and having end surfaces to support an object, wherein the burls each comprise a first body protruding portion and a second body protruding portion located further from the main body than the first body protruding portion, and the first body portions of the burls comprise a different material than the second body portions of the burls.
16. The holder according to claim 15 , wherein the support member forms a recess in which is located the one or more openings.
17. The holder according to claim 15 , wherein the flexible element is configured to allow movement of the support member primarily in a plane of the main body across which the object is arranged to be supported.
18. The holder according to claim 15 , wherein the main body is formed of a different material from the burls.
19. The holder according to claim 15 , wherein the second body portions comprise a material selected from: diamond, diamond-like carbon, SiC, SiO 2 , TIN, cubic boron nitride, silicon nitride, titanium, titanium carbide, cordierite or aluminum nitride.
20. A lithographic apparatus comprising the substrate holder of claim 15 .