Substrate holder, lithographic apparatus, device manufacturing method, and method of manufacturing a substrate holder
A substrate holder for a lithographic apparatus has a planarization layer provided on a surface thereof. The planarization layer provides a smooth surface for the formation of an electronic component such as a thin film electronic component. The planarization layer may be provided in multiple sub layers. The planarization layer may smooth over roughness caused by removal of material from a blank to form burls on the substrate holder.
1. A substrate holder for use in a lithographic apparatus, the substrate holder comprising:
a main body having a surface;
a plurality of burls projecting from the surface and having end surfaces;
a planarization layer provided on at least part of the surface of the main body; and
a heater and/or a sensor provided on the planarization layer.
2. The substrate holder according to claim 1 , wherein the planarization layer has a surface roughness Ra less than about 1.5 μm.
3. The substrate holder according to claim 1 , wherein the planarization layer is formed of a silicon-based material.
4. The substrate holder according to claim 3 , wherein the planarization layer is formed of a silicon oxide or silicon nitride based material.
5. The substrate holder according to claim 3 , wherein the planarization layer includes a functional group selected from the group consisting of: hydrogen, methyl, fluoro, and vinyl.
6. The substrate holder according to claim 1 , wherein the planarization layer is formed of a carbon-based material.
7. The substrate holder according to claim 1 , wherein the planarization layer is formed of benzocyclobutene.
8. The substrate holder according to claim 1 , wherein the main body is formed of a material selected from the group consisting of: SiC (silicon carbide), SiSiC (siliconised silicon carbide), Si 3 N 4 (silicon nitrite), quartz, and Zerodur™ glass ceramic.
9. The substrate holder according to claim 1 , wherein the planarization layer is formed of a plurality of separately formed sub-layers.
10. The substrate holder according to claim 1 , wherein the planarization layer has a thickness in the range of from about 0.2 μm to about 200 μm.
11. The substrate holder according to claim 1 , wherein the planarization layer does not cover at least the end surfaces of the burls.
12. The substrate holder according to claim 11 , wherein the burls have side surfaces and the planarization layer does not cover at least part of the side surfaces of the burls.
13. The substrate holder according to claim 1 , wherein the heater and/or sensor is a thin-film component.
14. A lithographic apparatus, comprising:
a support structure configured to support a patterning device;
a projection system arranged to project a beam patterned by the patterning device onto a substrate; and
a substrate holder arranged to hold the substrate, the substrate holder comprising:
a main body having a surface,
a plurality of burls projecting from the surface and having end surfaces,
a planarization layer provided on at least part of the surface of the main body, and
a heater and/or a sensor provided on the planarization layer.
15. The lithographic apparatus according to claim 14 , wherein the planarization layer is formed of a silicon-based material.
16. The lithographic apparatus according to claim 14 , wherein the planarization layer is formed of benzocyclobutene.
17. A device manufacturing method using a lithographic apparatus, the method comprising:
projecting a beam of radiation onto a substrate; whilst
holding the substrate in a substrate holder;
wherein the substrate holder comprises: a main body having a surface; a plurality of burls projecting from the surface and having end surfaces; a planarization layer provided on at least part of the surface of the main body; and a heater and/or a sensor provided on the planarization layer.
18. A method of manufacturing a substrate holder for use in a lithographic apparatus, the method comprising:
providing a main body having a surface and a plurality of burls projecting from the surface and having end surfaces; and
forming a planarization layer on at least part of the surface of the main body, wherein the planarization layer is formed of a plurality of separately formed sub-layers; and
providing an electronic component that overlies the sub-layers.
19. A substrate holder for use in a lithographic apparatus, the substrate holder comprising:
a main body having a surface;
a plurality of burls projecting from the surface and having end surfaces; and
a planarization layer provided on at least part of the surface of the main body to cover an area encompassing the plurality of burls, the planarization layer provided between the burls but not covering the end surfaces of the plurality of burls, and the planarization layer comprising a first surface and a second surface opposite the first surface, wherein the first surface of the planarization layer fills in roughness of the surface of the main body between the burls and the surface roughness Ra of the second surface is less than the surface roughness Ra of the first surface.
20. The substrate holder of claim 19 , further comprising an electronic component overlying the second surface.