SUBSTRATE FREEZE DRY APPARATUS AND METHOD

• US 20120304483A1
• Filed: 10/13/2011
• Published: 12/06/2012
• Est. Priority Date: 05/31/2011
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Sirard, Stephen M., Hymes, Diane, Schoepp, Alan M.
• Granted Patent: US 9,673,037 B2
• Time in Patent Office: Days
• US Class Current: 34/289
• CPC Class Codes: H01L 21/02057 Cleaning during device manufacture
• CPC Class Codes: H01L 21/67034 for drying
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/6831 using electrostatic chucks

Abstract

An apparatus for freeze drying a substrate is provided. A chamber for receiving a substrate is provided. An electrostatic chuck (ESC) for supporting and electrostatically clamping the substrate is within the chamber. A temperature controller controls the temperature of the electrostatic chuck. A condenser is connected to the chamber. A vacuum pump is in fluid connection with the chamber.

Claims

1. An apparatus for freeze drying a substrate, comprising:

a chamber for receiving a substrate;

an electrostatic chuck (ESC) for supporting and electrostatically clamping the substrate within the chamber;

a temperature controller for controlling the temperature of the electrostatic chuck;

a condenser connected to the chamber; and

a vacuum pump in fluid connection with the chamber.

2. The apparatus, as recited in claim 1, further comprising at least one thermoelectric unit embedded in the electrostatic chuck for providing a temperature differential between a part of the electrostatic chuck in which the at least one thermoelectric unit is embedded and a remainder of the electrostatic chuck.

3. The apparatus, as recited in claim 1, further comprising an atmosphere control system for providing a controlled atmosphere in the chamber.

4. The apparatus, as recited in claim 1, further comprising a wet transfer station for transferring a wet substrate into the chamber and sealing the chamber.

5. The apparatus, as recited in claim 1, wherein the temperature controller comprises a chiller in fluid connection with the electrostatic chuck.

6. The apparatus, as recited in claim 1, wherein the temperature controller further comprises a second chiller in fluid connection with the electrostatic chuck.

7. The apparatus, as recited in claim 1, further comprising a plasma source connected to the chamber for providing a plasma inside the chamber.

8. The apparatus, as recited in claim 1, further comprising heat lamps for heating a surface of the substrate.

9. The apparatus, as recited in claim 1, further comprising a manometer connected with the chamber for measuring pressure within the chamber.

10. The apparatus, as recited in claim 1, further comprising an optical endpoint spectrometer connected to the chamber.

11. The apparatus, as recited in claim 1, further comprising a voltage source for providing a voltage for clamping the substrate to the electrostatic chuck.

12. The apparatus, as recited in claim 1, wherein the vacuum pump and condenser comprise a cryopump that provides a vacuum and condenses fluid from the chamber.

13. The apparatus, as recited in claim 1, further comprising a backside heating and cooling system connected to the electrostatic chuck.

14. A method, for freeze drying a liquid from a substrate, comprising:

displacing the liquid with a drying chemistry;

placing the substrate on an electrostatic chuck in a drying chamber;

chucking the substrate to the electrostatic chuck;

using the electrostatic chuck to back side cool the substrate below the freezing point of the drying chemistry to freeze the drying chemistry;

reducing the pressure in the chamber to remove the frozen drying chemistry; and

heating the substrate to vaporize the drying chemistry without melting the drying chemistry.

15. The method, as recited in claim 14, further comprising precooling the electrostatic chuck to a temperature below the freezing point of the drying chemistry before placing the substrate on the electrostatic chuck.

16. The method, as recited in claim 14, further comprising providing an inert or reducing gas to provide an oxygen free atmosphere within the chamber.

17. The method, as recited in claim 14, wherein the using the electrostatic chuck to back side cool the substrate causes the drying chemistry to freeze to complete solidification, while eliminating meta stable states of the drying chemistry

18. The method, as recited in claim 14, wherein the drying chemistry comprises water and tert-butanol.