Substrate processing with rapid temperature gradient control

• US 9,275,887 B2
• Filed: 07/14/2007
• Issued: 03/01/2016
• Est. Priority Date: 07/20/2006
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Matyushkin, Alexander, Katz, Dan, Holland, John, Panagopoulos, Theodoros, Willwerth, Michael D.
• Primary Examiner(s): Capozzi, Charles
• Application Number:
  US11/778,019
• Publication Number:
  US 20080017104A1
• Time in Patent Office: 3,153 Days
• Field of Search: 361/234, 438/710, 165/104.26, 165/185
• US Class Current: 1/1
• CPC Class Codes: B05C 13/00 Means for manipulating or holding work, e.g. for separate articles B05C1/0821 takes precedence
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks
• CPC Class Codes: H05B 3/0047 for semiconductor manufacture

Abstract

A substrate processing chamber comprises an electrostatic chuck comprising a ceramic puck having a substrate receiving surface and an opposing backside surface. In one version, the ceramic puck comprises a thickness of less than 7 mm. An electrode is embedded in the ceramic puck to generate an electrostatic force to hold a substrate, and heater coils in the ceramic puck allow independent control of temperatures at different heating zones of the puck. A chiller provides coolant to coolant channels in a base below the ceramic puck. A controller comprises temperature control instruction sets which set the coolant temperature in the chiller in relation prior to ramping up or down of the power levels applied to the heater.

Claims

1. A substrate support assembly comprising:

(a) a ceramic puck comprising a substrate receiving surface having a plurality of ports to provide a heat transfer gas to the surface, central and peripheral portions, and an opposing backside surface, the ceramic puck comprising (i) an electrode embedded therein to generate an electrostatic force to retain a substrate placed on the substrate receiving surface, and (ii) a heater embedded therein to heat the substrate, the heater comprising a first heater coil located at the peripheral portion of the ceramic puck and a second heater coil located at the central portion of the ceramic puck;

(b) a coolant base comprising a coolant channel to circulate coolant therethrough, the coolant channel comprising an inlet and terminus;

(c) a compliant layer bonding the backside surface of the ceramic puck to the coolant base; and

(d) a controller configured to (i) independently apply different electrical power levels to the first and second heater coils, and control the temperature and flow rate of coolant passed through the coolant channel of the coolant base to increase a coolant temperature of the coolant to a higher level prior to ramping up the power level applied to the first and second heater coils in the ceramic puck, or decrease the coolant temperature of the coolant to a lower level prior to ramping down the power level applied to the first and second heater coils in the ceramic puck, (ii) receive temperature signals from a temperature sensor; and

(iii) serve as a feedback control loop to adjust the power applied to the heater coils and the flow of fluid through the coolant channel of the coolant base in response to the temperature signals from the temperature sensor.

2. A support assembly according to claim 1 wherein the inlet and terminus of the coolant channel are adjacent to one another and the coolant channel loops back upon itself.

3. A support assembly according to claim 1 wherein the opposing backside surface of the ceramic puck comprises a plurality of spaced apart mesas, with first mesas adjacent to the inlet of the coolant channel and second mesas that are distal from the inlet of the coolant channel, and comprising at least one of:

(i) the first mesas are spaced apart a first distance that is larger than a second distance between the second mesas; and

(ii) the first mesas each have a first contact region having a dimension that is smaller than a dimension of a second contact region of the second mesas.

4. A support assembly according to claim 1 wherein the ceramic puck comprises a thickness of from about 4 mm to about 7 mm.

5. A support assembly according to claim 1 wherein the ceramic puck is composed of aluminum oxide.

6. A support assembly according to claim 5 wherein the electrode and heater each comprise either tungsten or molybdenum.

7. A support assembly according to claim 1 wherein the first and second heater coils are radially spaced apart and concentric about one another.

8. A support assembly according to claim 1 wherein the heater comprises a resistance of about 8.5 ohms.

9. A support assembly according to claim 1 wherein the first heater coil comprises first loops spaced apart a first distance and the second heater coil comprises second loops spaced apart a second distance that is greater than the first distance.

10. A support assembly according to claim 9 wherein the second loops are positioned about a lift pin hole in the ceramic puck.

15. A support assembly according to claim 1 wherein the compliant layer bonding the backside surface of the ceramic puck to the coolant base comprises silicon material or acrylic.

16. A support assembly according to claim 1 wherein heat transfer gas conduits traverse the ceramic puck to terminate in the ports on the substrate receiving surface, and wherein the conduits comprise a first gas conduit located to supply heat transfer gas to a central heating zone of the substrate receiving surface, and a second gas conduit located to supply heat transfer gas to a peripheral heating zone of the substrate receiving surface.

18. A support assembly according to claim 1 comprising optical temperature sensors to measure the temperatures of overlying central and peripheral portions of a substrate.

19. A support assembly according to claim 18 wherein the optical temperature sensors include a first sensor positioned at the central heating zone of the ceramic puck and a second sensor positioned at a peripheral heating zone of the ceramic puck.

11. A substrate processing apparatus comprising:

(a) a process chamber comprising a substrate support mounted therein, the substrate support comprising;

(i) a ceramic puck comprising a substrate receiving surface having a plurality of ports to provide a heat transfer gas to the receiving surface, and an opposing backside surface, the ceramic puck comprising a thickness of less than 7 mm, and having embedded therein an electrode and a heater, the heater comprising a first heater coil located at a peripheral portion of the ceramic puck and a second heater coil located at a central portion of the ceramic puck;

(ii) a coolant base below and bonded to the backside surface of the ceramic puck with a compliant layer, the coolant base comprising coolant channels; and

(iii) a chiller to maintain a coolant at a coolant temperature for passing the coolant through the coolant channels of the coolant base;

(b) a gas distributor to provide a process gas to the process chamber;

(c) a gas energizer to energize the process gas;

(d) a gas exhaust port through which to exhaust the process gas from the chamber; and

(e) a controller configured to independently apply different electrical power levels to the first and second heater coils, and control the temperature and flow rate of coolant passed through the coolant channels of the coolant base to (i) increase the coolant temperature in the chiller to a higher level prior to ramping up the power level applied to the heater in the ceramic puck, or (ii) decrease the coolant temperature in the chiller to a lower level prior to ramping down the power level applied to the heater in the ceramic puck.

12. An apparatus according to claim 11 wherein the controller is configured to change the coolant temperature in the chiller at least 1 second before ramping up or ramping down the power level applied to the heater in the ceramic puck.

13. An apparatus according to claim 11 wherein the controller is configured to change the coolant temperature by at least about 10°

C.

14. An apparatus according to claim 11 wherein the compliant layer bonding the coolant base to the backside surface of the ceramic puck comprises silicon material or acrylic.

17. A support assembly according to claim 11 wherein the first and second heater coils comprise a total resistance of less than 10 ohms.