Multi-zone substrate temperature control system and method of operating

• US 20070235134A1
• Filed: 03/28/2006
• Published: 10/11/2007
• Est. Priority Date: 03/28/2006
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Iimuro, Shunichi
• Granted Patent: US 8,343,280 B2
• Time in Patent Office: Days
• US Class Current: 156/345.270
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/68714 the wafers being placed on a susceptor, stage or support

Abstract

A method and system for multi-zone control of temperature for a substrate is described. The temperature control system comprises a heat exchanger coupled to two or more fluid channels in a substrate holder configured to support the substrate. The heat exchanger is configured to adjust the temperature of a heat transfer fluid flowing through the two or more fluid channels. The temperature control system further comprises a heat transfer unit having an inlet that is configured to receive heat transfer fluid from the heat exchanger at a bulk fluid temperature. Additionally, the heat transfer unit comprises a first outlet configured to couple a portion of the heat transfer fluid at a first temperature less than the bulk temperature to a first fluid channel of the two or more fluid channels, and a second outlet configured to couple a remaining portion of the heat transfer fluid at a second temperature greater than the bulk fluid temperature to a second fluid channel of the two or more fluid channels.

Claims

1. A temperature control system, comprising:

a first fluid channel coupled to a first thermal region of a processing element in a processing system, and configured to receive a first flow of heat transfer fluid at a first fluid temperature;

a second fluid channel coupled to a second thermal region of said processing element in said processing system, and configured to receive a second flow of heat transfer fluid at a second fluid temperature;

a heat exchanger unit configured to provide a bulk flow of heat transfer fluid at a bulk fluid temperature, wherein said bulk flow of said heat transfer fluid supplies said first flow of said heat transfer fluid and said second flow of said heat transfer fluid; and

a heat transfer unit coupled to said heat exchanger and configured to receive said bulk flow of heat transfer fluid, wherein said heat transfer unit is configured to provide said first flow of heat transfer fluid at said first fluid temperature and provide said second flow of heat transfer fluid at said second fluid temperature by transferring heat between a first heat transfer region through which said first flow passes and a second heat transfer region through which said second flow passes.

2. The temperature control system of claim 1, wherein said heat transfer unit transfers heat from said first flow of heat transfer fluid to said second flow of heat transfer fluid such that said first fluid temperature is less than said bulk fluid temperature and said second fluid temperature is greater than said bulk fluid temperature.

3. The temperature control system of claim 1, wherein said heat transfer unit comprises one or more thermo-electric devices having a first surface coupled to said first heat transfer region and a second surface coupled to said second heat transfer region, wherein said one or more thermo-electric devices are coupled to a power source in order to generate a temperature difference between said first surface and said second surface.

4. The temperature control surface of claim 3, wherein the magnitude of said temperature difference between said first surface and said second surface of said one or more thermo-electric devices is varied by adjusting an electrical current coupled from said power source to said one or more thermo-electric devices.

5. The temperature control system of claim 3, wherein the direction of heat transfer between said first flow of heat transfer fluid and said second flow of heat transfer fluid is varied by adjusting the polarity of an electrical voltage coupled from said power source to said one or more thermoelectric devices.

6. The temperature control system of claim 1, wherein said heat transfer unit comprises a first inlet coupled to said first heat transfer region and a second inlet coupled to said second heat transfer region, and wherein said first inlet and said second inlet are coupled to an outlet of said heat exchanger such that said bulk flow of heat transfer fluid is split to form said first flow and said second flow.

7. The temperature control system of claim 1, wherein said heat transfer unit comprises a first outlet coupled to said first heat transfer region and an inlet of said first fluid channel, and a second outlet coupled to said second heat transfer region and an inlet of said second fluid channel.

8. The temperature control system of claim 1, wherein said heat exchanger is coupled to an outlet of said first fluid channel and an outlet of said second fluid channel, and configured to receive said heat transfer fluid from said first fluid channel and said second fluid channel.

9. The temperature control system of claim 1, wherein said processing element comprises a substrate holder in said processing system.

10. The temperature control system of claim 9, wherein said first thermal region is proximate a central portion of said substrate, and said second thermal region is proximate an edge portion of said substrate.

11. The temperature control system of claim 9, wherein said substrate comprises a semiconductor wafer.

12. The temperature control system of claim 9, wherein said substrate is clamped to said substrate holder.

13. The temperature control system of claim 9, wherein a heat transfer gas is provided to a space between a backside surface of said substrate and an upper surface of said substrate holder.

14. The temperature control system of claim 1, further comprising:

a controller coupled to said heat exchanger and configured to adjust the flow rate of said bulk flow of heat transfer fluid or said bulk fluid temperature or both.

15. The temperature control system of claim 1, further comprising:

a controller coupled to said heat transfer unit and configured to adjust the flow rate of said first flow of heat transfer fluid, said first fluid temperature, the flow rate of said second flow of heat transfer fluid, or said second fluid temperature, or any combination of two or more thereof.

16. A method of controlling temperature of a substrate held on a substrate holder using the temperature control system of claim 1, comprising:

providing a first heat transfer fluid to said first fluid channel;

providing a second heat transfer fluid to said second fluid channel; and

controlling a first fluid temperature of said first heat transfer fluid relative to a second fluid temperature of said second heat transfer fluid using said heat transfer unit.

17. A computer readable medium containing program instructions for execution on a computer system, which when executed by the computer system, cause the computer system to control the temperature control system of claim 1 to perform the steps of:

providing a first heat transfer fluid to said first fluid channel;

providing a second heat transfer fluid to said second fluid channel; and

controlling a first fluid temperature of said first heat transfer fluid relative to a second fluid temperature of said second heat transfer fluid using said heat transfer unit.

18. A temperature control system, comprising:

a first thermal region of a processing element in a processing system, configured to receive a first flow of heat transfer fluid at a first fluid temperature;

a second thermal region of said processing element in said processing system, configured to receive a second flow of heat transfer fluid at a second fluid temperature; and

a heat transfer unit which transfers heat between said first flow of heat transfer fluid and said second flow of heat transfer fluid such that said first temperature is different than said second fluid temperature.