System using hot and cold fluids to heat and cool plate

• US 6,685,467 B1
• Filed: 11/10/2000
• Issued: 02/03/2004
• Est. Priority Date: 10/24/2000
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Subramanian, Ramkumar
• Primary Examiner(s): WILSON, GREGORY A
• Application Number:
  US09/709,827
• Time in Patent Office: 1,180 Days
• Field of Search: 432/253, 432/260, 219/388, 219/390, 219/540, 219/543, 427/510, 118/724, 118/725, 118/766, 62/33, 62/37, 165/80.1, 165/80.2, 165/80.4
• US Class Current: 432/253
• CPC Class Codes: F27B 17/0025 Especially adapted for treating semiconductor wafers
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67248 Temperature monitoring

Abstract

The invention provides systems and methods for controlling resist baking processes, such as PEB of chemically amplified photoresists. A system of the invention provides a baking plate through which hot fluids and cold fluids may be alternately circulated. The system takes measurements relating to temperature of the baking plate, temperature of the resist, and/or extent of the baking process. Using this data, the system controls the baking temperature and/or the overall extent of the baking process through control over the flow of hot and cold fluids. By alternating between hot and cold fluid circulation, systems of the invention provide rapidly responsive temperature control and/or abrupt termination of baking. Control over the baking process is further increased by implementing flow and process control separately over each of a plurality of different portions of a baking plate.

Claims

1. A baking system, comprising:

a baking plate within which are formed passages through which fluids maybe circulated;

a hot fluid supply and a cold fluid supply;

a flow control system;

a controller; and

a measuring system that measures chemical and/or physical changes in a resist coating on a substrate on the baking plate;

wherein the controller, in response to data provided by the measuring system, directs the flow control system to supply the passages with fluid from the hot fluid supply and/or fluid from the cold fluid supply, depending on whether the baking plate needs to be heated or cooled.

2. The baking system of claim 1, wherein the measuring system measures baking plate temperature.

3. The baking system of claim 1, wherein the measuring system measures the temperature of a resist coating On a substrate on the baking plate.

4. The baking system of claim 3, wherein the controller provides feedback control over the measured temperature.

5. The baking system of claim 3, wherein the controller uses the temperature measurements to estimate when a resist baking process is complete.

6. The baking system of claim 1, wherein the controller cools the baking plate when a measurement from the measuring system indicate a resist baking process is complete or nearly complete.

7. The baking system of claim 1, wherein the measuring system measures a line width for an image latent in the resist coating.

8. The baking system of claim 1, wherein the measuring system analyzes gases released from the resist coating.

9. The system of claim 1, wherein the baking plate has a porosity of at least about 0.80.

10. The system of claim 1, wherein the passages have rectangular cross-section.

11. A baking system, comprising:

baking plate within which are formed a plurality of segregated groups of passages, a portion of the baking plate being associated with each of the segregated groups of passages;

a hot fluid supply;

a cold fluid supply;

a flow control system that independently for a plurality of the segregated groups of passages controls the circulation of fluid from the hot fluid supply and fluid from the cold fluid supply, whereby the plurality of segregated groups of passages may be supplied with hot and/or cold fluid and associated portions of the baking plate may be either heated or cooled; and

a measuring system that measures chemical and or physical changes in a plurality of portions of a resist coating on a substrate on the baking plate.

12. The baking system of claim 11, farther comprising:

a controller;

wherein the controller, in response to data from the measuring system and independently for a plurality of the segregated groups of passages, directs the flow control system to supply the segregated groups of passages with fluid from the hot fluid supply and/or fluid from the cold fluid supply, depending on whether the controller determines the associated portions of the baking plate need to be heated or cooled.

13. The baking system of claim 12, wherein the measuring system measures the temperatures of a plurality of portions of the baking plate.

14. The baking system of claim 12, wherein the measuring system measures the temperature of a plurality of portions of a resist coating on a substrate on the baking plate.

15. The baking system of claim 14, wherein the controller provides feedback control over the measured temperatures.

16. The baking system of claim 14, wherein the controller uses the measured temperatures to estimate, for associated portions of the baking plate, when a baking process is complete for an associated portion of the resist coating.

17. The system of claim 12, wherein the baking plate has a porosity of at least about 0.80.

18. The system of claim 12, wherein the passages have rectangular cross-section.

19. The baking system of claim 11, wherein the controller cools a portion of the baking plate when a measurement from the measuring system indicate the baking process in the associated portion of the resist coating is complete or nearly complete.

20. The baking system of claim 11, wherein the measuring system measures line widths for an image latent in the resist coating.

21. The baking system of claim 11, wherein the measuring system analyzes gases released from the resist coating during a baking process.

22. A method of post baking a chemically amplified photoresist, comprising:

placing a photoresist coated substrate on a baking plate;

using a hot fluid supply to circulate hot fluid through the baking plate to heat the photoresist;

using a cold fluid supply to circulate cold fluid through the baking plate to cool the photoresist;

using a controller to control the flow of hot fluid and/or cold depending on whether the baking plate needs to be heated or cooled; and

employing a measuring system to measure chemical and/or physical changes in a plurality of portions of a resist coating on the substrate.

23. The method of claim 22, further comprising:

monitoring the progress of the post baking process and circulating the cold fluid only when the post baking process has proceeded to a satisfactory extent.

24. The method of claim 23, wherein monitoring the progress of the post baking process comprises monitoring a dimension of an image latent within the photoresist.

25. The method of claim 23, wherein monitoring the progress of the post baking process comprises monitoring the extent of a chemical reaction within the photoresist.

26. The method of claim 22, wherein:

the baking plate has formed within it a plurality of segregated passages through which fluids may be separately circulated a portion of the baking plate being associated with each group of segregated passages;

the hot and cold fluids are circulated through each group of passages; and

the circulation of hot and cold fluids is separately controlled for each of a plurality of the group of segregated passages.

27. The method of claim 26, wherein the circulation of hot and cold fluids is controlled based on temperature measurements.

28. The method of claim 27, wherein the temperature measurements are taken from portions of the baking plate.

29. The method of claim 27, wherein the temperature measurements are taken from portions of the photoresist.

30. A system for post baking a chemically amplified photoresist coating on a substrate, comprising:

means for circulating hot and cold fluids through a baking plate;

means for controlling the post baking of the chemically amplified photoresist via controlling the circulation of at least one of hot and cold fluids through at least one passage within the baking plate; and

means for measuring chemical and/or physical changes in a plurality of portions of a resist coating on the substrate.

31. The system of claim 30, wherein:

the means for circulating hot and cold fluids through the baking plate comprises means for circulating hot and cold fluids through a plurality of segregated groups of passages within the baking plate; and

the means for controlling the post baking of the chemically amplified photoresist comprises means for separately controlling the circulation of hot and cold fluids through each of a plurality of the segregated groups of passages within the baking plate.