SUBSTRATE SUPPORT WITH ELECTROSTATIC CHUCK HAVING DUAL TEMPERATURE ZONES

• US 20070258186A1
• Filed: 04/26/2007
• Published: 11/08/2007
• Est. Priority Date: 04/27/2006
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Holland, John, Panagopoulos, Theodoros, Matyushkin, Alexander, Koosau, Dennis
• Granted Patent: US 8,226,769 B2
• Time in Patent Office: Days
• US Class Current: 361/234
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6875 characterised by a plurality of individual support members, e.g. support posts or protrusions
• CPC Class Codes: Y10T 279/23 with magnetic or electrostatic means

Abstract

An electrostatic chuck for receiving a substrate in a substrate processing chamber comprises a ceramic puck having a substrate receiving surface and an opposing backside surface with a plurality of spaced apart mesas. An electrode is embedded in the ceramic puck to generate an electrostatic force to hold a substrate. Heater coils located at peripheral and central portions of the ceramic puck allow independent control of temperatures of the central and peripheral portions of the ceramic puck. The chuck is supported by a base having a groove with retained air. The chuck and base can also have an overlying edge ring and clamp ring.

Claims

1. An electrostatic chuck for receiving a substrate in a process chamber, the chuck comprising:

(a) a ceramic puck comprising a substrate receiving surface and an opposing backside surface comprising a plurality of spaced apart mesas;

(b) a plurality of heat transfer gas conduits traversing the ceramic body and terminating in ports on the substrate receiving surface to provide heat transfer gas to the substrate receiving surface;

(c) an electrode embedded in the ceramic puck to generate an electrostatic force to retain a substrate placed on the substrate receiving surface;

(d) first and second heater coils that are radially spaced apart, concentric about one another, and embedded in the ceramic puck, the first heater coil located at a peripheral portion of the ceramic puck and the second heater coil located at a central portion of the ceramic puck,

whereby the first and second heater coils allow independent control of the temperatures of the central and peripheral portions of the ceramic puck and cooperate with the mesas on the backside of the ceramic puck to allow regulation of a temperature profile of a substrate placed on the substrate receiving surface of the ceramic puck.

2. A chuck according to claim 1 wherein the first and second heater coils are arranged side by side and substantially in the same plane.

3. A chuck according to claim 1 wherein the first and second heater coils each comprise a resistive heating element comprising molybdenum.

4. A chuck according to claim 1 wherein the first and second heater coils each comprise an electrical resistance sufficiently high to maintain the substrate receiving surface of the ceramic puck at temperatures of from about 80 to about 250°

C.

5. A chuck according to claim 1 wherein the ceramic puck comprises at least one of aluminum oxide, aluminum nitride, silicon oxide, silicon carbide, silicon nitride, titanium oxide, zirconium oxide, and mixtures thereof.

6. A chuck according to claim 1 wherein the mesas on the backside surface on the ceramic puck each comprise cylindrical mounds.

7. A chuck according to claim 1 wherein the ceramic puck comprises a peripheral ledge to receive a clamp ring that forms a seal around the ceramic puck.

8. A chuck according to claim 1 further comprising first and second optical temperature sensors embedded in the ceramic puck, with the first sensor positioned at the central portion of the ceramic puck and the second sensor positioned at the peripheral portion of the ceramic puck.

9. A chuck according to claim 1 wherein the optical temperature sensors comprise a phosphorous layer in front of an optical fiber embedded in a copper tip.

10. A chuck according to claim 1 wherein the optical temperature sensors comprise a temperature isolation jacket.

11. A ring assembly for an electrostatic chuck supported by a base in a substrate process chamber, the electrostatic chuck comprising a ceramic puck with a peripheral ledge having first and second steps, and the base having a top surface with a chuck receiving portion and a peripheral portion extending beyond the chuck, the ring assembly comprising:

(a) a clamp ring comprising (i) a top surface, (ii) an upper lip that extends radially inward from the top surface to rest on the first step of the peripheral ledge of the ceramic puck, and (iii) an outer side surface which forms a radially outer perimeter; and

(b) an edge ring comprising a band having a foot resting on the top surface of the clamp ring, an annular outer wall enclosing the outer side surface of the clamp ring, and a flange covering the second step of the peripheral ledge of the ceramic puck,

whereby the clamp ring and the edge ring cooperate to reduce the formation of process deposits on the electrostatic chuck during the processing of a substrate.

12. An assembly according to claim 11 wherein the edge ring comprises a ceramic.

13. An assembly according to claim 12 wherein the ceramic comprises quartz.

14. An assembly according to claim 11 wherein the clamp ring comprises a metal or ceramic.

15. An assembly according to claim 14 wherein the clamp ring comprises holes that are secured to a peripheral portion of the top surface of the base to form a gas-tight seal.

16. An assembly according to claim 11 wherein the lip of the clamp ring comprises an undersurface that rests on the first step of the peripheral ledge of the ceramic puck, and wherein the undersurface comprises a polymer.

17. An assembly according to claim 16 wherein the polymer comprises polyimide.

18. A base for supporting an electrostatic chuck in a substrate process chamber, the electrostatic chuck comprising (i) a ceramic puck having a substrate receiving surface and an opposing backside surface, (ii) a plurality of heat transfer gas conduits traversing the ceramic puck and terminating in ports on the substrate receiving surface to provide heat transfer gas to the substrate receiving surface, (iii) an electrode embedded in the ceramic puck to generate an electrostatic force, and (iv) first and second heater coils embedded in the ceramic puck, the base comprising:

(a) a metal body having a top surface comprising (i) a chuck receiving portion to receive the backside surface of the ceramic puck and comprising a peripheral groove to contain air about the backside surface of the ceramic puck, and (ii) a peripheral portion extending radially outwardly beyond the ceramic puck;

(b) a plurality of heat transfer gas passages for supplying heat transfer gas to the heat transfer gas conduits in the ceramic puck;

(c) at least one fluid channel in the metal body for circulating fluid therein; and

(d) an electrical terminal assembly for conducting electrical power to the electrode of the electrostatic chuck, the electrical terminal assembly comprising a ceramic insulator jacket having embedded therein a plurality of terminal posts for supplying electrical power to the electrode and heater coils of the electrostatic chuck, each terminal post surrounded by a contact band comprising a metal and having a plurality of heat transfer louvers.

19. A base according to claim 18 wherein the backside surface of the ceramic puck comprises a plurality of mesas, and wherein the peripheral groove on the chuck receiving surface of the base cooperates with the mesas to control a rate of heat transfer from a peripheral portion of the ceramic puck.

20. A base according to claim 18 wherein the chuck receiving surface further comprises a central groove that cooperates with the mesas to control a rate of heat transfer from a peripheral portion of the ceramic puck.

21. A substrate support for receiving a substrate in a process chamber, the assembly comprising:

(a) an electrostatic chuck comprising;

(i) a ceramic puck comprising a substrate receiving surface and an opposing backside surface, and having a peripheral ledge with a step;

(ii) a plurality of heat transfer gas conduits traversing the ceramic body and terminating in ports on the substrate receiving surface to provide heat transfer gas to the substrate receiving surface;

(iii) an electrode embedded in the ceramic puck, the electrode being chargeable to generate an electrostatic force to retain a substrate placed on the substrate receiving surface;

(b) a base comprising a metal body having a top surface comprising a chuck receiving portion to receive the backside surface of the ceramic puck and a peripheral portion extending radially outwardly beyond the ceramic puck;

(c) a edge ring that rests on the step of the peripheral ledge of the ceramic puck to form a seal with an overlying edge of a substrate retained on the receiving surface of the ceramic puck; and

(d) a clamp ring secured to the peripheral portion of the base, the clamp ring having a lip that extends radially inward to rest on the peripheral ledge of the ceramic puck to form a gas-tight seal with the ceramic puck.

22. A support according to claim 21 wherein the edge ring comprises a ceramic.

23. A support according to claim 22 wherein the ceramic comprises quartz.

24. A support according to claim 21 wherein the clamp ring comprises aluminum or titanium.

25. A support according to claim 21 wherein the lip of the clamp ring comprises an undersurface in contact with the ceramic puck, and wherein the undersurface comprises a polymer layer.

26. A support according to claim 21 wherein the ceramic puck comprises first and second heater coils that are radially spaced apart and concentric about one another, with the first heater coil at a peripheral portion of the ceramic puck and the second heater coil at a central portion of the ceramic puck.

27. A support according to claim 21 wherein the backside surface of the ceramic puck comprises a plurality of mesas.

28. A support according to claim 27 wherein the chuck receiving surface of the base comprises a peripheral groove to contain air about the mesas of the backside of the ceramic puck.

29. A support according to claim 28 wherein the top surface of the base comprises a central groove.

30. A support according to claim 21 wherein the base comprises an electrical terminal assembly for conducting electrical power to the electrode of the electrostatic chuck, the terminal assembly comprising a ceramic insulator jacket having embedded therein a plurality of terminal posts for supplying electrical power to the electrode and heater coils of the electrostatic chuck, each terminal post surrounded by a contact band.

31. A clamp ring for a process chamber comprising a base having a top surface with a chuck receiving portion to support an electrostatic chuck and a peripheral portion, the electrostatic chuck comprising a ceramic puck with a peripheral ledge having a first step and a second step, and an edge ring resting on the second step of the ceramic puck, the clamp ring comprising:

(a) an annular body having a top surface for supporting the edge ring and a bottom surface with a plurality of holes adapted to be secured to the peripheral portion of the top surface of the base;

(b) an upper lip extending radially inward to rest on the first step of the peripheral ledge of the ceramic puck;

(c) a radially outer side surface, and

(d) a foot extending downward from the radially outer side surface to rest on the peripheral portion of the top surface of the base.

32. A clamp ring according to claim 31 wherein the annular body is secured to the peripheral portion of the top surface of the base by screws or bolts that mate with the holes.

33. A clamp ring according to claim 31 wherein the upper lip comprises a downwardly projecting bump that rests on the first step of the peripheral ledge of the ceramic puck.

34. A clamp ring according to claim 33 wherein the annular body comprises a bottom recess radially outward of the downwardly projecting bump.

35. A clamp ring according to claim 31 wherein the upper lip of the clamp ring comprises an undersurface which rests on the first step of the peripheral ledge of the ceramic puck.

36. A clamp ring according to claim 35 wherein the undersurface comprises a polymer.

37. A clamp ring according to claim 36 wherein the polymer comprises polyimide.

38. A clamp ring according to claim 31 wherein the clamp ring comprises a metal or ceramic.

39. A clamp ring according to claim 38 wherein the ceramic comprises aluminum oxide.

40. An edge ring for a process chamber having (i) a base, (ii) an electrostatic chuck on a base, the electrostatic chuck comprises a ceramic puck having a peripheral ledge with a step, and (iii) a clamp ring having an upper lip extending radially inward to rest on the step of the peripheral ledge of the ceramic puck, an outer side surface, and a top surface,

the edge ring comprising:

(a) a band comprising a foot resting on the top surface of the clamp ring;

(b) an annular outer wall enclosing the outer side surface of the clamp ring; and

(c) an inner flange covering the step of the peripheral ledge of the ceramic puck.

41. An edge ring according to claim 40 wherein the band comprises a ceramic.

42. An edge ring according to claim 41 wherein the ceramic comprises quartz.

43. An edge ring for a process chamber having (i) a base, (ii) an electrostatic chuck on the base, the electrostatic chuck comprises a ceramic puck having a peripheral ledge with a step, and (iii) a clamp ring having a top surface and an upper lip extending radially inward from the top surface to rest on the step of the peripheral ledge of the ceramic puck, and an outer side surface,

the edge ring comprising:

(a) a wedge-shaped band comprising an inclined upper surface and a lower surface that covers the top surface of the clamp ring;

(b) an inner flange extending radially inward from the wedge-shaped band, the inner flange comprising a foot that can rest on the step of the peripheral ledge of the ceramic puck; and

(c) an outer flange extending radially outward from the wedge-shaped band, the outer flange comprising a radially inward facing surface that covers the outer side surface of the clamp ring.

44. An edge ring according to claim 43 wherein the inner flange comprises a bottom surface that is stepped up in relation to the lower surface of wedge-shaped band.

45. An edge ring according to claim 43 wherein the inner flange comprises a radially inward perimeter comprising upper and lower steps.

46. An edge ring according to claim 43 wherein the inner flange comprises a curved edge that joins the inclined upper surface of the wedge-shaped band.

47. An edge ring according to claim 43 wherein the outer flange comprises a bottom wall that extends downwardly in relation to the lower surface of wedge-shaped band.

48. An edge ring according to claim 43 wherein the outer flange comprises a slanted perimeter edge.

49. An edge ring according to claim 43 wherein the wedge-shaped band comprises a ceramic.

50. An edge ring according to claim 49 wherein the ceramic comprises quartz.

51. An electrostatic chuck for receiving a substrate in a process chamber, the electrostatic chuck comprising:

(a) a ceramic puck comprising;

(i) a substrate receiving surface comprising a plurality of raised plateaus of mesas, the raised plateaus being separated by a pattern of grooves;

(ii) a plurality of heat transfer gas conduits traversing through the ceramic puck and terminating in peripheral and central ports located in the pattern of grooves on the substrate receiving surface, the gas conduits capable of providing heat transfer gas to different zones of the substrate receiving surface; and

(iii) a peripheral ledge with first and second steps, the second step being radially outward of, and lower than, the first step;

(b) an electrode embedded in the ceramic puck to generate an electrostatic force to retain a substrate placed on the substrate receiving surface.

52. A chuck according to claim 51 wherein the raised plateaus of mesas each comprise from about 10 to about 1000 mesas.

53. A chuck according to claim 51 wherein the mesas are raised cylindrical bumps.

54. A chuck according to claim 51 wherein the mesas have average diameters of sized from about 5 to about 50 microns.

55. A chuck according to claim 51 wherein the mesas have a height of from about 0.5 to about 5 mm.

56. A chuck according to claim 51 wherein the pattern of grooves comprise radial and circular arms which are interconnected to one another.

57. A chuck according to claim 55 wherein the peripheral ports terminate in the arcuate cut-outs.

58. A chuck according to claim 57 comprising radially inner and outer gas sealing rims surrounding the peripheral ports.

59. A chuck according to claim 51 wherein the central ports terminate at intersections of the central and radial grooves.

60. A chuck according to claim 51 wherein the ceramic puck comprises aluminum oxide, aluminum nitride, silicon oxide, silicon carbide, silicon nitride, titanium oxide, zirconium oxide, or mixtures thereof.