Wafer dryer and method for drying a wafer

• US 20050257396A1
• Filed: 03/09/2005
• Published: 11/24/2005
• Est. Priority Date: 03/09/2004
• Status: Active Grant

• Current Assignee: Lam Research AG (LAM Research Corporation)
• Original Assignee: SEZ AG (LAM Research Corporation)
• Inventors: Ratra, Jagjit S., Ferrell, Gary W.
• Granted Patent: US 7,181,863 B2
• Time in Patent Office: Days
• US Class Current: 34/340
• CPC Class Codes: H01L 21/67034 for drying

Abstract

A wafer dryer and method featuring a nebulizer which emits a pressurized drying liquid stream that converges with an opposed pressurized non-reactive carrier gas stream to produce a drying liquid fog. The pressurized non-reactive gas spray device is disposed partially within a tub and partially within a wafer bath vessel housing a wafer to be dried. The tub has a vent port for allowing the drying liquid fog to pass into the wafer bath vessel to adhere to exposed wafer surfaces and displace remaining liquid on wafer surfaces, thus drying the wafer. The tub may further include a drain for draining drying liquid not converted into the fog or which has condensed. The vent also may include means for retaining larger drying liquid fog particles which allows smaller drying liquid fog particles to pass into the wafer bath vessel.

Claims

1. A wafer dryer comprising:

a wafer bath vessel having means for supporting at least one wafer having an exposed surface to be dried; and

a tub mounted to the bath vessel, the tub having a drying liquid spray device and a non-reactive carrier gas spray device opposing the drying liquid spray device, the spray device emitting a stream of pressurized drying liquid that converges with a stream of opposed pressurized non-reactive carrier gas emitted by the spray device of pressurized non-reactive gas to produce a drying liquid fog, the tub also having means for venting the drying liquid fog into the wafer bath vessel, the drying liquid fog drying the wafer.

2. The apparatus of claim 1 further comprising means for retaining relatively larger sized drying liquid fog particles and wherein said means for venting include means for venting the non-retained drying liquid fog particles into the wafer bath vessel.

3. The apparatus of claim 1 wherein said means for retaining larger sized drying liquid fog particles includes a lip.

4. The apparatus of claim 1 wherein said means for venting the drying liquid fog into the wafer bath vessel includes a port disposed in said tub.

5. The apparatus of claim 1 wherein said drying liquid is isopropyl alcohol and said non-reactive carrier gas is nitrogen.

6. The apparatus of claim 1 wherein the tub includes a decreasing volume of water.

7. The apparatus of claim 1 wherein said tub further has a source of non-reactive carrier gas introducing a non-reactive carrier into said tub.

8. The apparatus of claim 1 wherein said drying liquid spray device includes a tip with a tip opening through which the pressurized drying liquid stream is emitted in a first direction and wherein the pressurized non-reactive carrier gas source includes an opening through which the pressurized drying liquid stream is emitted in a second direction opposing the first direction.

9. The apparatus of claim 8 further comprising a throat adjacent to the spray device tip, the non-reactive carrier gas source disposed at least partially in the throat and partially in the wafer bath vessel, the throat comprising an opening, wherein the pressurized non-reactive carrier gas is emitted through the throat.

10. The apparatus of claim 9 wherein said spray device tip is disposed within the throat opening, partially blocking the opening, and wherein said drying liquid stream and said non-reactive gas stream converge in the throat.

11. The apparatus of claim 9 wherein said spray device tip is disposed adjacent the throat opening and said non-reactive gas stream is emitted through the throat opening to converge with said drying liquid stream beneath said spray device tip and above said throat opening.

12. The apparatus of claim 9 wherein said pressurized non-reactive gas stream source emits a central stream of non reactive gas and one or more streams of non-reactive gas through openings in a body of said source co-axial with said central stream.

13. The apparatus of claim 12 further comprising a flange disposed about a lower portion of said throat, said flange including openings receiving said one or more co-axial streams of non-reactive gas.

14. The apparatus of claim 1 wherein said drying liquid spray device is a nebulizer.

15. A method for drying a wafer comprising:

emitting a stream of pressurized drying liquid;

emitting a stream of pressurized non-reactive carrier gas opposed to said drying liquid stream, said streams converging to produce a drying liquid fog;

venting the drying liquid fog into a wafer bath vessel having at least one wafer with an exposed surface to be dried; and

drying the exposed surface to be dried with said drying liquid fog.

16. The method of claim 15 further comprising providing a non-reactive carrier gas stream for moving said drying liquid fog toward said exposed surface.

17. The method of claim 15 wherein said drying liquid is isopropyl alcohol and said non-reactive carrier gas is nitrogen.

18. The method of claim 15 further comprising retaining relatively larger particles of the liquid drying fog and venting relatively smaller particles of the liquid drying fog.