Substrate holder, lithographic apparatus, device manufacturing method, and method of manufacturing a substrate holder
A substrate holder for a lithographic apparatus has a main body having a thin-film stack provided on a surface thereof. The thin-film stack forms an electronic or electric component such as an electrode, a sensor, a heater, a transistor or a logic device, and has a top isolation layer. A plurality of burls to support a substrate are formed on the thin-film stack or in apertures of the thin-film stack.
1. A substrate holder for use in a lithographic apparatus, the substrate holder comprising:
a main body having a smooth and flat surface;
a thin-film stack of layers provided on the surface and forming an electronic or electric component; and
a plurality of burls provided on the thin-film stack and having end surfaces to support a substrate,
wherein the main body is formed of a different material than the burls.
2. The substrate holder according to claim 1 , wherein at least one burl comprises a first layer of a first material and a second layer of a second material that is different from the first material.
3. The substrate holder according to claim 1 , wherein the thin-film stack includes at least one via in electrical contact with a burl.
4. The substrate holder according to claim 1 , wherein the thin-film stack forms a plurality of electric components.
5. The substrate holder according to claim 4 , wherein a first electric component and a second electric component of the plurality of electric components are arranged in a single layer of the thin-film stack.
6. The substrate holder according to claim 4 , wherein a first electric component and a second electric component of the plurality of electric components are arranged in two separate layers of the thin-film stack.
7. The substrate holder according to claim 1 , wherein the component is a component selected from the group consisting of: an electrode, a heater, a sensor, a transistor and a logic device.
8. A substrate holder for use in a lithographic apparatus, the substrate holder comprising:
a main body having a smooth and flat surface;
a thin-film stack of layers provided on the smooth and flat surface and forming an electronic or electric component, the thin-film stack having a plurality of apertures formed therein; and
a plurality of projections, each projection provided in an aperture of the thin-film stack, the plurality of projections being configured to support a substrate.
9. 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 being according to claim 1 .
10. A method of manufacturing a substrate holder for use in a lithographic apparatus, the method comprising:
providing a main body having a smooth and flat surface;
forming a thin-film stack of layers on the smooth and flat surface of the main body, the thin-film stack forming an electronic or electric component; and
forming a plurality of burls on the thin-film stack, the burls projecting from the stack and having end surfaces to support a substrate.
11. The method according to claim 10 , wherein forming the plurality of burls comprises:
forming a layer of burl-forming material on the thin-film stack;
forming a mask on the layer of burl-forming material;
etching the burl-forming material through the mask; and
removing the mask.
12. A method of manufacturing a substrate holder for use in a lithographic apparatus, the method comprising:
providing a main body having a smooth and flat surface;
forming a thin-film stack of layers on the smooth and flat surface of the main body;
forming a plurality of apertures in the thin-film stack; and
forming a plurality of burls in the apertures of the thin-film stack, the burls projecting from the stack and having end surfaces to support a substrate.
13. The substrate holder according to claim 1 , wherein the burls are formed from at least one material selected from the group consisting of: diamond-like carbon, SiC, SiO 2 , TiN and CrN.
14. The substrate holder according to claim 1 , wherein the main body is formed from at least one material selected from the group consisting of: Zerodur, Cordierite, SiC, AlN, SiSiC, ceramic and glass-ceramic.
15. The substrate holder according to claim 1 , wherein the component in the thin-film stack is located at least partly between a burl and the main body.
16. The substrate holder according to claim 1 , wherein burls project from the thin-film stack by a distance selected from the range of from 1 to 20 μm.
17. The substrate holder according to claim 1 , wherein the burls are cylindrical.
18. The substrate holder according to claim 1 , wherein the burls taper away from the thin-film stack.
19. The substrate holder according to claim 1 , wherein the surface of the main body is the surface of a planarization layer of the main body.
20. The method according to claim 10 , comprising forming the burls by a process selected from the group consisting of:
deposition and selective etching;
sputtering through a patterned resist layer;
deposition through a hardmask; and
laser-sintering.