High conductivity electrostatic chuck
View Patent ↗In accordance with an embodiment of the invention, there is provided an electrostatic chuck comprising a conductive path covering at least a portion of a workpiece-contacting surface of a gas seal ring of the electrostatic chuck, the conductive path comprising at least a portion of an electrical path to ground; and a main field area of a workpiece-contacting surface of the electrostatic chuck comprising a surface resistivity in the range of from about 10 8 to about 10 12 ohms per square.
1. An electrostatic chuck, comprising:
a conductive path covering at least a portion of a workpiece-contacting surface of a gas seal ring of the electrostatic chuck, the conductive path comprising a coating covering at least a portion of an outside edge of the gas seal ring and at least a portion of an outside edge of the electrostatic chuck and comprising at least a portion of an electrical path to ground, the conductive path comprising a surface resistivity in the range of from about 10 5 ohms per square to about 10 7 ohms per square; and
a main field area of a workpiece-contacting surface of the electrostatic chuck comprising a surface resistivity in the range of from about 10 8 to about 10 12 ohms per square, the main field area comprising at least one embossment extending above surrounding portions of the main field area; and
a conductive coating on a workpiece-contacting surface of the at least one embossment.
2. An electrostatic chuck according to claim 1 , wherein the conductive path comprises diamond-like carbon.
3. An electrostatic chuck according to claim 2 , wherein the conductive path comprises doped diamond-like carbon.
4. An electrostatic chuck according to claim 3 , wherein the conductive path comprises hydrogenated carbon doped with nitrogen.
5. An electrostatic chuck according to claim 1 , wherein the conductive path comprises a coating of a thickness less than about 1 micron.
6. An electrostatic chuck according to claim 1 , wherein the conductive path wraps underneath an insulator layer of the electrostatic chuck.
7. An electrostatic chuck according to claim 1 , wherein the main field area comprises silicon carbide.
8. An electrostatic chuck according to claim 7 , wherein the main field area comprises a surface resistivity in the range of from about 10 9 to about 10 11 ohms per square.
9. An electrostatic chuck according to claim 1 , wherein the electrostatic chuck comprises a conductive grounding layer, at least a portion of which is underneath an insulator layer of the electrostatic chuck, the conductive grounding layer electrically contacting the conductive path.
10. An electrostatic chuck according to claim 9 , wherein at least a portion of an outside edge of the conductive grounding layer is covered by the conductive path.
11. An electrostatic chuck according to claim 9 , wherein the conductive grounding layer electrically contacts a grounding pin of the electrostatic chuck.
12. An electrostatic chuck according to claim 9 , further comprising an electrically conductive epoxy layer underlying at least a portion of the conductive grounding layer.
13. An electrostatic chuck according to claim 1 , wherein the conductive path of the electrostatic chuck and the conductive coating on the workpiece-contacting surface of the at least one embossment each comprise a diamond like carbon coating.
14. An electrostatic chuck according to claim 1 , wherein a base of the electrostatic chuck comprises a chamfered area on one or more edges of the base.
15. An electrostatic chuck according to claim 14 , wherein the conductive path electrically contacts the base through a conductive epoxy in the chamfered area.
16. An electrostatic chuck according to claim 15 , wherein the conductive path comprises a coating covering at least a portion of an outside edge of the electrostatic chuck, the conductive path wrapping underneath an insulator layer of the electrostatic chuck.
17. An electrostatic chuck according to claim 1 , further comprising at least one conductive pattern on the workpiece-contacting surface of the electrostatic chuck, the at least one conductive pattern electrically contacting the conductive path.
18. An electrostatic chuck according to claim 17 , wherein the at least one conductive pattern comprises a metal coated with a conductive coating.
19. An electrostatic chuck according to claim 17 , wherein the at least one conductive pattern comprises at least one of: a spoke extending towards the center of the electrostatic chuck; a ring around a gas hole of the electrostatic chuck; and a trace between two embossments on the workpiece-contacting surface of the electrostatic chuck.
20. An electrostatic chuck according to claim 1 , wherein the main field area of the electrostatic chuck comprises a polymer.
21. An electrostatic chuck according to claim 20 , wherein the main field area comprises at least one embossment extending above surrounding portions of the main field area, the at least one embossment comprising a polymer.
22. An electrostatic chuck according to claim 20 , wherein the main field area comprises a surface resistivity in the range of from about 10 8 to about 10 10 ohms per square.
23. An electrostatic chuck according to claim 20 , wherein the conductive path comprises a conductive coating, the conductive coating also covering at least a portion of the main field area.
24. An electrostatic chuck, comprising:
a conductive path electrically connected to at least a portion of a workpiece-contacting surface of the electrostatic chuck, the conductive path comprising a coating covering at least a portion of an outside edge of the electrostatic chuck and comprising at least a portion of an electrical path to ground; and
a main field area of a workpiece-contacting surface of the electrostatic chuck comprising a surface resistivity in the range of from about 10 8 to about 10 10 ohms per square, the main field area comprising a blanket layer and at least one embossment extending above surrounding portions of the main field area, the blanket layer and the at least one embossment each comprising a polymer comprising carbon nanotubes;
the conductive path further comprising a portion extending from under the blanket layer to the coating covering the at least a portion of the outside edge of the electrostatic chuck; and
a conductive coating on a workpiece-contacting surface of the at least one embossment.
25. An electrostatic chuck according to claim 24 , wherein the polymer comprises at least one of: carbon nanotube filled polyether imide; carbon nanotube filled polyether ether ketone; and carbon nanotube filled polyimide.