Method for multi-step temperature control of a substrate

• US 7,297,894 B1
• Filed: 09/25/2006
• Issued: 11/20/2007
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Tsukamoto, Yuji
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US11/526,119
• Time in Patent Office: 421 Days
• Field of Search: 219/494, 219/497, 219/121.43, 219/121.41, 219/121.44, 219/121.4, 219/444.1, 118/724, 118/725, 438/714, 438/715, 156/345.53, 156/345.52
• US Class Current: 219/121.58
• CPC Class Codes: H01L 21/67103 mainly by conduction
• CPC Class Codes: H01L 21/67109 mainly by convection

Abstract

A method of changing the temperature of a substrate during processing of the substrate includes providing the substrate on a substrate holder, the substrate holder including a temperature controlled substrate support for supporting the substrate, a temperature controlled base support for supporting the substrate support and a thermal insulator interposed between the temperature controlled substrate support and the temperature controlled base support. The method further includes setting the temperature of the base support to a first base temperature corresponding to a first processing temperature of the substrate, setting the substrate support to a first support temperature corresponding to the first processing temperature of the substrate, setting the temperature of the base support to a second base temperature corresponding to a second processing temperature of the substrate, and setting the substrate support to a second support temperature corresponding to the second processing temperature of the substrate.

Claims

1. A method for controlling the temperature of a substrate in a substrate processing system, the substrate processing system including a substrate holder having a substrate support with a plurality of temperature sensors reporting at least a temperature at an inner region and an outer region of said substrate and first and second heating elements heating respectively said inner and outer regions, said substrate holder including a base support having a cooling element for cooling said inner and outer regions, said substrate holder further including a thermal insulator disposed between said substrate support and said base support, said first and second heating elements and said cooling element being controlled by a temperature control system to maintain said substrate holder at a selectable set-point temperature, the method comprising:

selecting a first base temperature for said base support;

selecting a second base temperature for said base support;

selecting a first inner set-point temperature and a first outer set-point temperature;

selecting a second inner set-point temperature and a second outer set-point temperature;

setting said base support to said first base temperature using said cooling element;

placing said substrate on said substrate holder;

heating said inner region of said substrate to said first inner set-point temperature and said outer region of said substrate to said first outer set-point temperature;

processing said substrate for a first period of time at said first inner and outer set-point temperatures;

changing the base temperature for said base support from said first base temperature to said second base temperature different from the first inner set-point temperature and the first outer set-point temperature;

changing the temperature of said inner and outer regions of said substrate to said second inner and outer set-point temperatures; and

processing said substrate for a second period of time at said second inner and outer set-point temperatures.

2. The method of claim 1, wherein said first inner set-point temperature is less than said second inner set-point temperature, and said first outer set-point temperature is less than said second outer set-point temperature.

3. The method of claim 2, wherein said first base temperature is less than said second base temperature.

4. The method of claim 1, wherein said first inner set-point temperature is greater than said second inner set-point temperature, and said first outer set-point temperature is greater than said second outer set-point temperature.

5. The method of claim 4, wherein said first base temperature is greater than said second base temperature.

6. The method of claim 1, wherein said setting said base support to said first base temperature using said cooling element comprises flowing a heat transfer fluid through said base support, said heat transfer fluid having a fluid temperature corresponding to said first base temperature.

7. The method of claim 1, wherein said changing the base temperature for said base support from said first base temperature to said second base temperature comprises:

flowing a heat transfer fluid through said base support, said heat transfer fluid having a fluid temperature corresponding to said first base temperature; and

changing the fluid temperature of said heat transfer fluid from said first base temperature to said second base temperature.

8. The method of claim 1, wherein said heating said inner region of said substrate to said first inner set-point temperature comprises heating said inner region of said substrate by coupling electrical power to an inner resistive heating element, and wherein said heating said outer region of said substrate to said first outer set-point temperature comprises heating said outer region of said substrate by coupling electrical power to an outer resistive heating element.

9. The method of claim 8, wherein said changing the temperature of said inner and outer regions of said substrate to said second inner and outer set-point temperatures comprises increasing the electrical power to said inner resistive heating element and increasing the power to said outer resistive heating element.

10. The method of claim 9, wherein said changing the base temperature for said base support from said first base temperature to said second base temperature comprises increasing the base temperature for said base support from said first base temperature to said second base temperature.

11. The method of claim 8, wherein said changing the temperature of said inner and outer regions of said substrate to said second inner and outer set-point temperatures comprises decreasing the electrical power to said inner resistive heating element and decreasing the power to said outer resistive heating element.

12. The method of claim 11, wherein said changing the base temperature for said base support from said first base temperature to said second base temperature comprises decreasing the base temperature for said base support from said first base temperature to said second base temperature.

13. The method of claim 1, further comprising:

clamping said substrate to said substrate holder.

14. The method of claim 13, further comprising:

providing a heat transfer gas to the backside surface of said substrate on said substrate holder.

15. The method of claim 14, further comprising:

configuring the upper surface of said substrate holder to have an inner thermal region for supplying a first heat transfer gas to the backside surface of said substrate and an outer thermal region for supplying a second heat transfer gas to the backside surface of said substrate;

selecting a first inner pressure for said inner thermal region and a first outer pressure for said outer thermal region;

selecting a second inner pressure for said inner thermal region and a second outer pressure for said outer thermal region;

during said heating, providing a first heat transfer gas to said inner thermal region at said first inner pressure and a second heat transfer gas to said outer thermal region at said first outer pressure; and

during said changing the temperature of said inner and outer regions of said substrate, providing said first heat transfer gas to said inner thermal region at said second inner pressure and said second heat transfer gas to said outer thermal region at said second outer pressure.

16. The method of claim 1, wherein said processing said substrate for a first period of time comprises etching a layer of material on said substrate.

17. The method of claim 16, wherein said processing said substrate for a second period of time comprises etching another layer of material underlying said layer of material etched during said first period of time.

18. A method for controlling the temperature of a substrate in a substrate processing system, the substrate processing system including a substrate holder having a substrate support with a plurality of temperature sensors reporting at least a temperature at an inner region and an outer region of said substrate and first and second heating elements heating respectively said inner and outer regions, said substrate holder including a base support having a cooling element for cooling said inner and outer regions, said substrate holder further including a thermal insulator disposed between said substrate support and said base support, said first and second heating elements and said cooling element being controlled by a temperature control system to maintain said substrate holder at a selectable set-point temperature, the method comprising:

selecting a first base temperature for said base support;

selecting a second base temperature for said base support;

selecting a first inner set-point temperature and a first outer set-point temperature;

selecting a second inner set-point temperature and a second outer set-point temperature;

setting said base support to said first base temperature using said cooling element;

placing said substrate on said substrate holder;

heating said inner region of said substrate to said first inner set-point temperature and said outer region of said substrate to said first outer set-point temperature;

changing the base temperature for said base support from said first base temperature to said second base temperature different from the first inner set-point temperature and the first outer set-point temperature; and

ramping the temperature of said inner and outer regions of said substrate to said second inner and outer set-point temperatures while processing said substrate for a period of time.

19. A method of changing the temperature of a substrate during processing of the substrate, comprising:

providing the substrate on a substrate holder, the substrate holder comprising a temperature controlled substrate support for supporting the substrate, a temperature controlled base support for supporting the substrate support and a thermal insulator interposed between the temperature controlled substrate support and the temperature controlled base support;

setting the temperature of the base support to a first base temperature corresponding to a first processing temperature of said substrate;

setting the substrate support to a first support temperature corresponding to said first processing temperature of said substrate;

setting the temperature of the base support to a second base temperature corresponding to a second processing temperature of said substrate; and

setting the substrate support to a second support temperature corresponding to said second processing temperature of said substrate wherein the first processing temperature and the second processing temperature are different.

20. The method of claim 19, wherein at least one of said first and second support temperatures is a temperature profile that varies across an area of said substrate support.