Method of removing particles and a liquid from a surface of substrate

• US 6,676,765 B2
• Filed: 05/21/2001
• Issued: 01/13/2004
• Est. Priority Date: 09/24/1997
• Status: Expired due to Fees

• Current Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Original Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International)
• Inventors: Mertens, Paul, Meuris, Mark, Heyns, Marc
• Primary Examiner(s): Markoff, Alexander
• Application Number:
  US09/862,072
• Publication Number:
  US 20010022186A1
• Time in Patent Office: 967 Days
• Field of Search: 134/6, 134/18, 134/26, 134/30, 134/32, 134/902, 15/77, 151/02, 15/882, 15/883, 153/08, 15/971, 344/43, 344/95
• US Class Current: 134/6
• CPC Class Codes: H01L 21/67028 for cleaning followed by drying, rinsing, stripping, blasting or the like
• CPC Class Codes: H01L 21/67034 for drying
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

The present invention is related to a method of removing particles and a liquid from a surface of a substrate using at least one rotating cleaning pad. The approach, according to the present invention, is a technique wherein a sharp liquid-vapor boundary is created on the surface of the substrate adjacent to the last wetted rotating cleaning pad of a plurality of rotating cleaning pads and particularly between this last wetted rotating cleaning pad and a first edge of the substrate.

Claims

1. A method for the removal of particles and liquid from at least one surface of a substrate using at least one rotating pad, the method comprising the steps of:

creating a relative linear motion at a predetermined speed between the at least one wetted rotating pad and the substrate;

contacting said surface of said substrate at a first edge with the at least one wetted rotating pad;

applying a substance on said surface adjacent to the at least one wetted rotating pad and applying the substance between the at least one wetted rotating pad and said first edge, said substance reducing surface tension of said liquid, said substance being at least partially miscible with said liquid and when mixed with said liquid yielding a mixture having a surface tension being lower than that of said liquid; and

continuing said linear relative motion from said first edge to a second edge, opposite to said first edge, while contacting said surface of said substrate with the at least one wetted rotating pad and while supplying said substance, the step of continuing said linear relative motion thereby removing at least a portion of said particles and at least a portion of said liquid from said surface of said substrate.

2. A method as recited in claim 1, wherein by supplying said substance, a defined liquid-vapor boundary is created on said surface of said substrate adjacent to the at least one rotating pad.

3. A method as recited in claim 1, wherein during said relative linear motion, said liquid is supplied to the at least one wetted rotating pad contacting said surface of said substrate.

4. A method as recited in claim 1, wherein said liquid is selected from a group consisting of a mixture of NH₄OH, H₂O₂ and H₂O;

a mixture of NH₄OH and H₂O;

a mixture of HCl, H₂O₂ and H₂O;

a mixture of HCl and H₂O;

H₂O; and

a mixture of H₂O and an acid, said mixture of H₂O and an acid having a pH between 2 and 6.

5. A method as recited in claim 1, wherein said substance comprises a vaporised substance which is miscible with said liquid and when mixed with said liquid yields a mixture having a surface tension being lower than that of said liquid.

6. A method as recited in claim 5, wherein said vaporised substance is selected from a group consisting of isopropyl alcohol (IPA), diacetone, ethylglycol, ethyllactate and methylpyrrolidon or a mixture thereof.

7. A method as recited in claim 1, wherein said substance comprises a mixture of a vaporised substance and a gas, said mixture being at least partially miscible with said liquid and when mixed with said liquid yields a mixture having a surface tension being lower than that of said liquid.

8. A method as recited in claim 7, wherein said vaporised substance is selected from a group consisting of isopropyl alcohol (IPA), diacetone, ethylglycol and methylpyrrolidon or a mixture thereof and wherein said gas is an inert gas.

9. A method as recited in claim 1, wherein said substance comprises a gas which is miscible with said liquid and when mixed with said liquid yields a mixture having a surface tension being lower than that of said liquid.

10. A method as recited in claim 1, wherein the at least one rotating pad is cylindrical shaped and has a smooth outer edge.

11. A method as recited in claim 1, wherein a continuous contact area is formed between the at least one rotating pad and said surface.

12. A method as recited in claim 1, wherein the at least one rotating pad includes a plurality of wetted rotating pads.

13. A method as recited in claim 1, wherein said substance comprises a liquid.

14. A method as recited in claim 13, wherein said substance comprises a mist of liquid.

15. A method as recited in claim 1, wherein said substance comprises a gas.

16. A method as recited in claim 1, wherein said substance comprises a vaporised substance.

17. A method for the removal of particles and a liquid from a first and a second surface of a substrate using a first and a second rotating pads, the method comprising the steps of:

creating a relative linear motion at a predetermined speed between both said first and said second wetted rotating pads and said substrate;

contacting said first surface of said substrate at a first edge of said first wetted rotating pad and said second surface of said substrate at said first edge of said second wetted rotating pad, said contacting being established each time that during said relative linear motion said wetted rotating pad arrives at said first edge;

applying a substance on said first surface adjacent to said first rotating pad, and between said first wetted rotating pad and said first edge, said substance reducing surface tension of said liquid, said substance being at least partially miscible with said liquid and when mixed with said liquid yielding a mixture having a surface tension being lower than that of said liquid;

applying a substance on said second surface adjacent to a second wetted rotating pad, and between said second wetted rotating pad and said first edge, said substance reducing surface tension of said liquid, said substance being at least partially miscible with said liquid and when mixed with said liquid yielding a mixture having a surface tension being lower than that of said liquid;

continuing said linear relative motion from said first edge to a second edge, opposite to said first edge, while contacting said first surface of said substrate with said first wetted rotating pad and said second surface of said substrate with said second wetted rotating pad and while supplying said substance to said first and second surface, the step of continuing said linear relative motion thereby removing at least a portion of said particles and at least a portion of said liquid from said first and second surface of said substrate.

18. A method as recited in claim 17,

wherein the method of removal of particles and liquid uses a first and a second plurality of rotating pads, the first plurality of rotating pads including the first pad and the second plurality of rotating pads including the second pad,

wherein the step of contacting includes contacting said first surface of said substrate at a first edge with each of the wetted rotating pads of said first plurality of wetted rotating pads and said second surface of said substrate at said first edge with each of the wetted rotating pads of said second plurality of wetted rotating pads, said contacting being established each time that during said relative linear motion said wetted rotating pad arrives at said first edge;

wherein the step of applying a substance on said first surface includes applying a substance on said first surface adjacent to a first last wetted rotating pad, being the last wetted rotating pad of said first plurality of rotating pads arriving at said first edge, and between said first last wetted rotating pad and said first edge, said substance being at least partially miscible with said liquid and when mixed with said liquid yielding a mixture having a surface tension being lower than that of said liquid;

wherein the step of applying a substance on said second surface includes applying a substance on said second surface adjacent to a second last wetted rotating pad, being the last wetted rotating pad of said second plurality of rotating pads arriving at said first edge, and between said second wetted rotating pad and said first edge, said substance being at least partially miscible with said liquid and when mixed with said liquid yielding a mixture having a surface tension being lower than that of said liquid; and

wherein the step of continuing said linear relative motion includes continuing said linear relative motion from said first edge to a second edge, opposite to said first edge, while contacting said first surface of said substrate with said first plurality of wetted rotating pads and said second surface of said substrate with said second plurality of wetted rotating pad and while supplying said substance to said first and second surface to thereby remove said particles and said liquid from said first and second surface of said substrate.

19. A method for the removal of particles and a liquid from at least one surface of a substrate using at least one pair of rotating pads comprising the steps of:

creating a relative linear motion at a predetermined speed between the at least one pair of wetted rotating pads and a substrate;

contacting said surface of said substrate at a first edge with each of the wetted rotating pads of said at least one pair of wetted rotating pads each time that during said relative linear motion said wetted rotating pad arrives at said first edge;

locally heating said liquid on said surface adjacent to a last wetted rotating pad, being the last wetted rotating pad of said at least one pair of rotating pads arriving at said first edge, and between said last wetted rotating pad and said first edge, to thereby locally reduce the surface tension of said liquid; and

continuing said linear relative motion from said first edge to a second edge of said substrate, opposite to said first edge, while contacting said surface of said substrate with said at least one pair of wetted rotating pads and while locally heating said liquid to thereby remove said particles and said liquid from said surface of said substrate.

20. A method as recited in claim 19, wherein by locally heating said liquid, a defined liquid-ambient boundary is created on said surface of said substrate adjacent to said last rotating pad between said last wetted rotating pad and said first edge.

21. A method as recited in claim 19, wherein said heating is accomplished by means of dispensing a gas or a vapor or a mixture of a gas and a vapor.

22. A method as recited in claim 19, wherein said heating is accomplished by means of irradiation with an energetic beam.

23. A method as recited in claim 19,

wherein the method of removal of particles and liquid uses a plurality of rotating pads, the plurality of rotating pads including the at least one pair of rotating pads,

wherein the step of creating a relative linear motion includes creating a relative linear motion at a predetermined speed between the plurality of wetted rotating pads and a substrate,

wherein the step of contacting includes contacting said surface of said substrate at a first edge with each of the wetted rotating pads of said plurality of wetted rotating pads each time that during said relative linear motion said wetted rotating pad arrives at said first edge,

wherein the step of locally heating includes locally heating said liquid on said surface adjacent to a last wetted rotating pad, being the last wetted rotating pad of said plurality of rotating pads arriving at said first edge, and between said last wetted rotating pad and said first edge, to thereby locally reduce the surface tension of said liquid, and

wherein the step of continuing said linear relative motion includes continuing said linear relative motion from said first edge to a second edge of said substrate, opposite to said first edge, while contacting said surface of said substrate with said plurality of wetted rotating pads and while locally heating said liquid to thereby remove said particles and said liquid from said surface of said substrate.

24. A method for the removal of particles and liquid on at least one surface of a substrate using at least one rotating pad, the method comprising the steps of:

creating a relative motion between the at least one rotating pad and the substrate;

contacting the surface of the substrate on a first portion of the substrate with the at least one wetted rotating pad;

applying a substance on at least a portion of the surface, the substance reducing surface tension of said liquid, the substance being at least partially miscible with the liquid and when mixed with the liquid yielding a mixture having a surface tension being lower than that of the liquid; and

continuing said relative motion from the first portion of the substrate to a second portion of the substrate while contacting said surface of said substrate with the at least one wetted rotating pad and while supplying said substance, the step of continuing said relative motion thereby removing at least a portion of said particles and at least a portion of said liquid from said surface of said substrate.

25. A method as recited in claim 24, wherein the first portion of the substrate is a first edge and wherein the second portion of the substrate is a second edge, the second edge being opposite to the first edge.

26. A method as recited in claim 24, wherein the step of applying a substance includes applying the substance on said surface adjacent to the at least one wetted rotating pad.

27. A method as recited in claim 26, wherein the step of applying a substance further includes applying the substance between the at least one wetted rotating pad and said first edge.

28. A method as recited in claim 24,

wherein the at least one rotating pad includes a plurality of pads, and

wherein the step of applying includes applying the substance on said surface adjacent to a last wetted pad, the last wetted rotating pad being the last of said plurality of rotating pads to arrive at a first edge of the substrate.

29. A method as recited in claim 27,

wherein the at least one rotating pad includes a plurality of rotating pads, and wherein the step of applying includes applying the substance on the surface between a last wetted pad and a first edge the substrate, the last wetted pad being the last of the plurality of rotating pads to arrive at the first edge of the substrate.

30. A method for the removal of particles and liquid from at least one surface of a substrate using at least one rotating pad, the method comprising the steps of:

creating a relative linear motion at a predetermined speed between the at least one wetted rotating pad and the substrate;

contacting said surface of said substrate at a first edge with the at least one wetted rotating pad;

lowering surface tension of at least a portion of said liquid on said substrate; and

continuing said linear relative motion from said first edge to a second edge, opposite to said first edge, while contacting said surface of said substrate with the at least one wetted rotating pad and while lowering said surface tension, the step of continuing said linear relative motion thereby removing at least a portion of said particles and at least a portion of said liquid from said surface of said substrate.

31. A method as recited in claim 30, wherein the step of lowering surface tension of at least a portion of said liquid on said substrate comprises applying a gaseous substance on at least a portion of the surface, the gaseous substance being at least partially miscible with the liquid and when mixed with the liquid yielding a mixture having a surface tension being lower than that of the liquid.

32. A method as recited in claim 30, wherein the step of lowering surface tension of at least a portion of said liquid on said substrate comprises locally heating said liquid on said surface adjacent to the wetted rotating pad to thereby locally reduce the surface tension of said liquid.

33. A method as recited in claim 32, wherein said heating is accomplished by means of dispensing a gas or a vapor or a mixture of a gas and a vapor.

34. A method as recited in claim 32, wherein said heating is accomplished by means of irradiation with an energetic beam.