Claims
- 1. An electrostatic chuck comprising:
(a) an electrode capable of being electrically charged to electrostatically hold a substrate; and (b) a composite layer covering the electrode, the composite layer comprising:
(1) a first dielectric material covering a central portion of the electrode; and (2) a second dielectric material covering a peripheral portion of the electrode, the second dielectric material having a different composition than the composition of the first dielectric material.
- 2. An electrostatic chuck according to claim 1 wherein the first dielectric material comprises a resistance of from about 5×109 Ωcm to about 8×1010 Ωcm, and the second dielectric material comprises a resistivity of from about 1×1011 to about 1×1020 Ωcm.
- 3. An electrostatic chuck according to claim 1 wherein the first dielectric material is shaped as a disc and the second dielectric material is shaped as a rim about the disc.
- 4. An electrostatic chuck according to claim 1 wherein the first dielectric material comprises aluminum oxide and at least about 8 wt % titanium oxide.
- 5. An electrostatic chuck according to claim 1 wherein the chuck further comprises:
(i) at least one heat transfer fluid conduit extending through the electrode to allow passage of heat transfer fluid to the surface of the composite layer; and (ii) a plasma-deactivating material in an outlet of the conduit, the plasma-deactivating material capable of reducing plasma formation in the conduit ni plasma environments.
- 6. An electrostatic chuck comprising:
(a) an electrode capable of being electrically charged to generate an electrostatic charge to hold a substrate; and (b) a composite layer covering the electrode, the composite layer comprising:
(1) a first dielectric material covering a central portion of the electrode, the first dielectric material having a resistivity of from about 5×109 Ωcm to about 8×1010 Ωcm; and (2) a second dielectric material covering a peripheral portion of the electrode, the second dielectric material having a resistivity of from about 1×1011 to about 1×1020 Ωcm.
- 7. An electrostatic chuck according to claim 6 first dielectric comprises aluminum oxide and at least about 8 wt % titanium oxide.
- 8. A substrate processing chamber comprising an electrostatic chuck according to claim 1 and further comprising:
(1) a gas distributor for introducing a gas into the chamber; (2) a plasma generator that couples RF energy into the gas in the chamber; and (3) a throttled exhaust to exhaust gas from the chamber.
- 9. An electrostatic chuck fabrication process comprising:
(a) maintaining a chuck electrode facing arcing electrodes; (b) forming an electrical arc between the arcing electrodes; (c) flowing a gas stream through the electrical arc to absorb heat from the electrical arc; and (d) spraying a ceramic powder into the heated gas stream so that the ceramic powder impinges on the chuck electrode to form a ceramic layer thereon.
- 10. A process according to claim 9 comprising applying a voltage to the arcing electrodes to form the electrical arc that arc reaches temperatures sufficiently high to melt substantially all the ceramic powder sprayed into the arc.
- 11. A process according to claim 9 comprising maintaining a distance between the arcing electrodes and the chuck electrode of from about 50 to about 400 mm.
- 12. A process according to claim 9 comprising wherein the ceramic powder comprise aluminum oxides mixed with at least about 8 wt % titanium oxides.
- 13. A process according to claim 9 comprising spraying the ceramic powder by flowing the gas stream past a nozzle connected to a ceramic powder supply tank.
- 14. An electrostatic chuck fabrication process comprising:
(a) maintaining a chuck electrode facing arcing electrodes; (b) forming an electrical arc between the arcing electrodes; (c) flowing an inert gas stream through the electrical arc to absorb heat from the electrical arc; and (d) spraying a ceramic powder into the heated inert gas stream so that the ceramic powder impinges on the chuck electrode to form a ceramic layer having an electrical resistance of from about 5×109 to about 8×1010 Ωcm.
- 15. A process according to claim 14 comprising selecting a ceramic powder that provides a ceramic layer having an electrical resistance that is sufficiently low to allow accumulation of electrostatic charge in the layer during charging of the electrode, and the dissipation of the accumulated electrostatic charge in less than about 1 second when the electrode is not being charged.
- 16. A process according to claim 14 comprising applying a voltage to the arcing electrodes to form the electrical arc that arc reaches temperatures sufficiently high to melt substantially all the ceramic powder sprayed into the arc.
- 17. A process according to claim 14 comprising maintaining a distance between the arcing electrodes and the chuck electrode such that the ceramic powder is in a substantially molten state when it impinges on the chuck electrode.
- 18. A process according to claim 17 comprising maintaining a distance of from about 50 to about 400 mm.
- 19. A process according to claim 14 comprising wherein the ceramic powder comprise aluminum oxides mixed with at least about 8 wt % titanium oxides.
- 20. A process according to claim 14 comprising spraying the ceramic powder by flowing an inert gas stream past a nozzle connected to a ceramic powder supply tank.
- 21. An electrostatic chuck comprising:
(a) an electrode capable of being electrically charged to electrostatically hold a substrate; and (b) a dielectric layer covering at least a portion of an electrode, the dielectric layer having a resistivity in a range Δρ defined by:
(1) a first lower resistivity ρL that is sufficiently low (i) to allow a leakage current to flow from the electrode when an electrical charge is applied to the electrode to form accumulated electrostatic charge in the dielectric layer, and (ii) to allow the accumulated electrostatic charge to dissipate in less than about 1 second, when the electrical charge applied to the electrode is terminated; and (2) a second higher resistivity ρH that is sufficiently high to maintain the accumulated electrostatic charge in the dielectric layer during operation of the chuck.
- 22. An electrostatic chuck according to claim 21 further comprising:
(i) at least one heat transfer fluid conduit extending through the electrode to allow passage of heat transfer fluid to the surface of the composite layer; and (ii) a plasma-deactivating material in an outlet of the conduit, the plasma-deactivating material capable of reducing plasma formation in the conduit ni plasma environments.
- 23. A substrate processing chamber comprising an electrostatic chuck according to claim 21 and further comprising:
(1) a gas distributor for introducing a gas into the chamber; (2) a plasma generator that couples RF energy into the gas in the chamber; and (3) a throttled exhaust to exhaust gas from the chamber.
CROSS-REFERENCE
[0001] This application is a divisional of U.S. patent application Ser. No. 09/596,108, filed Jun. 16, 2000, entitled, “DIELECTRIC COVERED ELECTROSTATIC CHUCK”, which is a divisional of U.S. Pat. No. 6,108,189, issued on Aug. 22, 2000, entitled “ELECTROSTATIC CHUCK HAVING IMPROVED GAS CONDUITS”, which is a continuation-in-part of U.S. Pat. No. 5,720,818, issued Feb. 24, 1998, entitled, “Conduits for Flow of Heat Transfer Fluid to the Surface of an Electrostatic Chuck,” by Weldon et al., all of which are incorporated herein by reference.
Divisions (2)
|
Number |
Date |
Country |
Parent |
09596108 |
Jun 2000 |
US |
Child |
10095914 |
Mar 2002 |
US |
Parent |
08965690 |
Nov 1997 |
US |
Child |
09596108 |
Jun 2000 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
08639596 |
Apr 1996 |
US |
Child |
08965690 |
Nov 1997 |
US |