Polysilicon-silicon dioxide cleaning process performed in an integrated cleaner with scrubber

• US 6,358,325 B1
• Filed: 12/20/1999
• Issued: 03/19/2002
• Est. Priority Date: 08/22/1997
• Status: Expired due to Term

• Current Assignee: MOSAID Technologies Inc. (f/k/a Conversant Intellectual Property Management)
• Original Assignee: Micron Technology, Inc.
• Inventors: Andreas, Michael T.
• Primary Examiner(s): EL ARINI, ZEINAB
• Application Number:
  US09/468,022
• Time in Patent Office: 820 Days
• Field of Search: 134/2, 134/3, 134/6, 134/26, 134/30, 134/902, 15/77
• US Class Current: 134/2
• CPC Class Codes: B08B 1/00 Cleaning by methods involving the use of tools cleaning hollow articles by methods or apparatus specially adapted thereto B08B9/00
• CPC Class Codes: B08B 3/12 by sonic or ultrasonic vibrations washing or rinsing machines for crockery or tableware using sonic or ultrasonic waves A47L15/13; of natural teeth, of prostheses using ultrasonic techniques similar to those used for natural teeth A61C17/20; application of ultrasonic vibrations to chemical, physical or physico-chemical processes in general B01J19/10
• CPC Class Codes: H01L 21/67046 using mainly scrubbing means, e.g. brushes
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

An integrated cleaner with scrubber for cleaning and scrubbing semiconductor substrates that includes a housing that contains both a cleaning module and a scrubbing module. The cleaning module is capable of performing a wet-cleaning process on a batch of the semiconductor substrates. The cleaning module comprises a cleaning tank in which a batch of semiconductor substrates are cleaned. A megasonic device can be attached to the cleaning tank to enhance cleaning. The scrubbing module includes a plurality of scrubbers each of which scrubs a semiconductor substrate. The integrated cleaner with scrubber also comprises a robot for moving the semiconductor substrates between the cleaning and scrubbing modules. The inventive machine and process allows the cleaning and scrubbing of semiconductor substrates without removal from the housing while maintaining as static the surface chemistry of the semiconductor substrates, as well as the ambient humidity, the ambient temperature, and the ambient particle contamination within the housing. A drying module may also be included and made integral with in the housing to dry the semiconductor substrates.

Claims

1. A method for cleaning a surface on a semiconductor substrate, the method comprising:

removing a hydrophilic material from a semiconductor substrate to expose an interface with a hydrophobic material;

oxidizing the hydrophobic material while brush scrubbing the interface;

moving the semiconductor substrate away from said brush scrubbing, into a gaseous ambient, and then into a cleaning bath, said hydrophilic and hydrophobic materials having chemical properties and being unaffected during said moving while the semiconductor substrate is exposed to an ambient humidity, an ambient temperature, and an ambient particle contamination;

removing, within the cleaning bath, the oxide from the hydrophobic material;

moving the semiconductor substrate from the cleaning bath, into a gaseous ambient, and then into a dryer, said hydrophilic and hydrophobic materials being unaffected during said moving from the cleaning bath; and

drying, in the dryer, the hydrophilic and hydrophobic materials without oxidizing the hydrophobic material.

2. The method as defined in claim 1, wherein:

the ambient humidity, the ambient temperature, the ambient particle contamination on, and the chemical properties of the hydrophilic and hydrophobic materials are constant during both said moving from said brush scrubbing and said moving from the cleaning bath;

the hydrophilic material is silicon dioxide; and

the hydrophobic material is polysilicon.

3. A method for cleaning a semiconductor substrate, said method comprising:

simultaneously contacting a surface on each of a plurality of semiconductor substrates with a liquid non-abrasively, each surface on each said semiconductor substrate having an interface of polysilicon and silicon oxide;

transporting one of said plurality of semiconductor substrates out of contact with said liquid, into a gaseous ambient, and then into a scrubber, wherein the surface on said one of said plurality of semiconductor substrates is unaffected during the transportation thereof and while said one of said plurality of semiconductor substrates is exposed to an ambient humidity, an ambient, temperature, an ambient particle contamination, and the surface on said one of said plurality of semiconductor substrates has chemical properties; and

forming, adjacent to said interface of polysilicon and silicon oxide, an oxide from the polysilicon while applying an abrasive force to the surface of said one of said plurality of semiconductor substrates with said scrubber.

4. The method as defined in claim 3, further comprising:

moving one of said plurality of semiconductor substrates out of the scrubber, into a gaseous ambient, and then into a cleaning module, where the surface on said one of said plurality of semiconductor substrates is unaffected during the movement thereof;

removing, within the cleaning module, the oxide from the polysilicon on the surface of said one of said plurality of semiconductor substrates;

moving one of said plurality of semiconductor substrates out of the cleaning module, into a gaseous ambient, and then into a drying module, where the surface on said one of said plurality of semiconductor substrates is unaffected during said change of location; and

drying, in the drying module, the surface of said one of said plurality of semiconductor substrates without oxidizing the polysilicon thereof.

5. The method as defined in claim 4, wherein removing, within the cleaning module, the oxide from the polysilicon on the surface of said one of said plurality of semiconductor substrates is performed using a cleaning solution selected from the group consisting of hydrofluoric acid, a solution of ammonium fluoride and hydrofluoric acid, and a solution of hydrofluoric acid and tetramethylammonium hydroxide.

6. The method as defined in claim 4, wherein said drying is a process selected from the group consisting of a Marangoni dryer process and an IPA dryer process.

7. The method as defined in claim 4, further comprising, after said drying:

forming an electrically conductive material upon the polysilicon on the surface of said one of said plurality of semiconductor substrates.

8. The method as defined in claim 3, wherein during the transporting of said one of said plurality of semiconductor substrates out of contact with said liquid, into said gaseous ambient, and then into said scrubber, the ambient humidity, the ambient temperature, the ambient particle contamination on, and the chemical properties of the surface on said one of said plurality of semiconductor substrates are substantially the same.

9. The method as defined in claim 3, wherein said liquid has a chemical effect upon the surface on each of said plurality of semiconductor substrates.

10. The method as defined in claim 3, wherein said liquid simultaneously removes material non-abrasively from said surface on each of said plurality of semiconductor substrates.

11. The method as defined in claim 3, wherein the liquid is an etchant to material on said plurality of semiconductor substrates.

12. The method as defined in claim 3, wherein the liquid is applied to said plurality of semiconductor substrates in a wet clean tank.

13. The method as defined in claim 3, further comprising:

a deionized rinse of said one of said plurality of semiconductor substrates after applying said abrasive force to the surface of said one of said plurality of semiconductor substrates with said scrubber.

14. A method for cleaning a semiconductor substrate, said method comprising:

simultaneously removing material non-abrasively from a surface on each of a plurality of semiconductor substrates situated within a housing in a clean room environment, said surface on each said semiconductor substrate having an interface of polysilicon and silicon oxide;

transporting one of said plurality of semiconductor substrates to a scrubber situated within said housing in said clean room environment, wherein the surface on said one of said plurality of semiconductor substrates is unaffected during the transportation thereof, and while one of said plurality of semiconductor substrates is exposed to an ambient humidity, an ambient temperature, an ambient particle contamination and the surface on said one of said plurality of semiconductor substrates has chemical properties; and

forming an oxide on the polysilicon of the interface while removing material abrasively from the surface of said one of said plurality of semiconductor substrates with said scrubber situated within said housing in said clean room environment.

15. The method as defined in claim 14, further comprising:

moving one of said plurality of semiconductor substrates out of the scrubber, into a gaseous ambient within said housing in said clean room environment, and then into a cleaning module within said housing in said clean room environment, where the surface on said one of said plurality of semiconductor substrates is unaffected during the movement thereof;

removing, within the cleaning module, the oxide from the polysilicon on the surface of said one of said plurality of semiconductor substrates;

moving one of said plurality of semiconductor substrates out of the cleaning module, into a gaseous ambient within said housing in said clean room environment, and then into a drying module within said housing in said clean room environment, where the surface on said one of said plurality of semiconductor substrates is unaffected during said change of location; and

drying, in the drying module, the surface of said one of said plurality of semiconductor substrates without oxidizing the polysilicon thereof.

16. The method as defined in claim 15, wherein removing the oxide from the polysilicon on the surface is performed using a cleaning solution selected from the group consisting of hydrofluoric acid, a solution of ammonium fluoride and hydrofluoric acid, and a solution of hydrofluoric acid and tetramethylammonium hydroxide.

17. The method as defined in claim 15, wherein said drying is a process selected from the group consisting of a Marangoni dryer process and an IPA dryer process.

18. The method as defined in claim 15, further comprising, after said drying:

forming an electrically conductive material upon the polysilicon on the surface of said one of said plurality of semiconductor substrates.

19. The method as defined in claim 14, further comprising:

a deionized rinse of said one of said plurality of semiconductor substrates after removing material abrasively from the surface of said one of said plurality of semiconductor substrates with said scrubber situated within said housing in said clean room environment.

20. The method as defined in claim 14, wherein simultaneously removing material non-abrasively from said surface on each of said plurality of semiconductor substrates is conducted within said housing in said clean room environment with a chemical that is applied non-abrasively simultaneously to said surface on each of said plurality of semiconductor substrates.

21. The method as defined in claim 20, wherein the chemical applied non-abrasively to said surface on each of said plurality of semiconductor substrates is an etchant to said material on said plurality of semiconductor substrates.

22. The method as defined in claim 20, wherein the chemical applied non-abrasively to said surface on each of said plurality of semiconductor substrates is applied to said plurality of semiconductor substrates in a wet clean tank in which said plurality of semiconductor substrates are substantially submerged in the chemical.

23. The method as defined in claim 14, wherein said scrubber situated within said housing in said clean room environment scrubs one of said semiconductor substrates at a time.

24. The method as defined in claim 14, wherein said housing further comprises a plurality of said scrubbers that scrubs one of said semiconductor substrates at a time.

25. The method as defined in claim 14, wherein during the transporting of said one of said plurality of semiconductor substrates from said simultaneous removal of material to said scrubber, the ambient humidity, the ambient temperature, the ambient particle contamination on, and the chemical properties of the surface said one of said plurality of semiconductor substrates are substantially the same.

26. The method as defined in claim 14, wherein:

simultaneously removing material non-abrasively from a surface on each of a plurality of semiconductor substrates situated within a housing in a clean room environment includes simultaneously contacting said surface on each of said plurality of semiconductor substrates with a liquid; and

transporting one of said plurality of semiconductor substrates to a scrubber situated within said housing in said clean room environment includes transporting said one of said plurality of semiconductor substrates out of contact with said liquid into a gaseous ambient, and then into said scrubber.

27. The method as defined in claim 26, further comprising:

repeating for each semiconductor substrate in said plurality of semiconductor substrates said transporting one of said plurality of semiconductor substrates out of contact with said liquid, into a gaseous ambient, and then into said scrubber.

28. A method for cleaning and scrubbing semiconductor substrates, said method comprising:

loading a batch of the semiconductor substrates into a cleaning module within an integrated cleaner with scrubber, said integrated cleaner with scrubber being situated in a clean room environment, and said batch comprising a plurality of the semiconductor substrates each having a surface thereon with an interface of polysilicon and silicon oxide;

cleaning said batch of the semiconductor substrates in said cleaning module;

removing said batch of the semiconductor substrates from said cleaning module without exiting said integrated cleaner with scrubber, while said batch of the semiconductor substrates is exposed to an ambient humidity, an ambient temperature, an ambient particle contamination, and the surfaces of the semiconductor substrates in said batch have chemical properties;

loading the semiconductor substrates into a scrubber module within said integrated cleaner with scrubber without having removed the semiconductor substrates from said integrated cleaner with scrubber, the semiconductor substrates being singularly positioned within said scrubber module;

forming an oxide on the polysilicon of said interface on each said surface while scrubbing each said semiconductor substrate in said scrubbing module singularly,

removing the semiconductor substrates from said scrubbing module of said integrated cleaner with scrubber and loading the semiconductor substrates into the cleaning module within said integrated cleaner with scrubber without having removed the semiconductor substrates from said integrated cleaner with scrubber, the semiconductor substrates being singularly positioned within said scrubber module;

removing, within the cleaning module, the oxide from the polysilicon of the interface on the surface of each of the semiconductor substrates and loading the semiconductor substrates into a drying module without having removed the semiconductor substrates from said integrated cleaner with scrubber, the semiconductor substrates being singularly positioned within said scrubber module; and

drying, in the drying module, the semiconductor substrates without oxidizing the polysilicon of the interface on the surface of each of the semiconductor substrates.

29. The method as defined in claim 28, wherein removing the oxide from the polysilicon of the interface on the surface of each of the semiconductor substrates is performed using a cleaning solution selected from the group consisting of hydrofluoric acid, a solution of ammonium fluoride and hydrofluoric acid, and a solution of hydrofluoric acid and tetramethylammonium hydroxide.

30. The method as defined in claim 28, wherein said drying is a process selected from the group consisting of a Marangoni dryer process and an IPA dryer process.

31. The method as defined in claim 28, further comprising, after said drying:

forming an electrically conductive material upon the polysilicon of the interface in the surface of each of the semiconductor substrates.

32. The method as defined in claim 28, further comprising:

a deionized rinse of said one of said plurality of semiconductor substrates after scrubbing each said semiconductor substrate in said scrubbing module singularly.

33. A method as recited in claim 28, wherein prior to loading said batch of the semiconductor substrates into said cleaning module, the semiconductor substrates are individually loaded into a cassette to hold said batch of the semiconductor substrates.

34. A method as recited in claim 33, wherein the semiconductor substrates are individually loaded into said cassette by a material handling means for moving the semiconductor substrates.

35. The method as defined in claim 28, wherein:

cleaning said batch of the semiconductor substrates in said cleaning module includes simultaneously contacting said surface on each of said plurality of semiconductor substrates with a liquid;

removing said batch of the semiconductor substrates from said cleaning module without exiting said integrated cleaner with scrubber includes transporting said one of said plurality of semiconductor substrates out of contact with said liquid and into a gaseous ambient; and

loading the semiconductor substrates into said scrubber module within said integrated cleaner with scrubber without having removed the semiconductor substrates from said integrated cleaner with scrubber includes transporting said one of said plurality of semiconductor substrates from said gaseous ambient into said scrubber.

36. The method as defined in claim 35, further comprising:

for each semiconductor substrate in said batch of the semiconductor substrates, repeating;

the transporting said one of said plurality of semiconductor substrates out of contact with said liquid and into said gaseous ambient; and

the transporting said one of said plurality of semiconductor substrates from said gaseous ambient into said scrubber module.

37. A method as recited in claim 28, wherein the semiconductor substrates are unloaded individually from said scrubbing module by material handling means for moving the semiconductor substrates.

38. A method as recited in claim 28, wherein cleaning said batch of the semiconductor substrates in said cleaning module is a wet-cleaning process.

39. A method as recited in claim 28, wherein cleaning said batch of the semiconductor substrates in said cleaning module is an etch.

40. A method as recited in claim 28, wherein cleaning said batch of the semiconductor substrates in said cleaning module is a dry cleaning process.

41. A method as recited in claim 28, wherein said cleaning module comprises a cleaning tank, a drain for emptying said cleaning tank;

and a supply to provide a cleaning media; and

wherein cleaning said batch of the semiconductor substrates in said cleaning module comprises;

loading chemistry into said cleaning tank in said cleaning module;

filling said cleaning tank with said cleaning media;

processing said batch of the semiconductor substrates; and

draining said cleaning tank.

42. A method as recited in claim 41, wherein cleaning said batch of the semiconductor substrates in said cleaning module is repeated using a different cleaning media without removing said batch of the semiconductor substrates from said cleaning module.

43. A method as recited in claim 41, wherein said cleaning module further comprises a megasonic device associated with said cleaning tank.

44. A method as recited in claim 28, wherein said scrubber module comprises:

a plurality of brush scrubbers;

drive means for supplying power to said scrubbers; and

fluid supply means for providing liquid to each of said plurality of brush scrubbers.

45. A method as defined in claim 28, wherein between removing said batch of the semiconductor substrates from said cleaning module and loading the semiconductor substrates into the scrubber module, the surfaces on each removed one of said semiconductor substrates in said batch is unaffected.

46. The method as defined in claim 45, wherein between removing said batch of the semiconductor substrates from said cleaning module and loading the semiconductor substrates into the scrubber module, the ambient humidity, the ambient temperature, the ambient particle contamination on, and the chemical properties of the surfaces of each removed one of said semiconductor substrates in said batch is substantially the same.

47. A method for cleaning and scrubbing semiconductor substrates, said method comprising:

preparing a batch of the semiconductor substrates by loading the semiconductor substrates into a holder to hold the semiconductor substrates, said batch comprising a plurality of the semiconductor substrates;

loading said batch of the semiconductor substrates into a cleaning module within an integrated cleaner with scrubber, said integrated cleaner with scrubber being situated in a clean room environment, and said cleaning module comprising;

a cleaning tank;

a drain for emptying said cleaning tank; and

a supply to provide a cleaning solution;

wet-cleaning said batch of the semiconductor substrates in said cleaning module, said wet-cleaning comprising;

loading said batch into said cleaning tank;

filling said cleaning tank with said cleaning solution;

processing said batch of said the semiconductor substrates; and

draining said cleaning tank;

removing said batch of the semiconductor substrates from said cleaning module without exiting said integrated cleaner with scrubber;

loading the semiconductor substrates into a scrubber module within said integrated cleaner with scrubber without having removed the semiconductor substrates from the integrated cleaner with scrubber, the semiconductor substrates being singularly positioned within said scrubber module, wherein between removing said batch of the semiconductor substrates from said cleaning module and loading the semiconductor substrates into the scrubber module, the surfaces on each removed one of said semiconductor substrates in said batch is unaffected, said scrubber module comprising;

a plurality of brush scrubbers; and

drive means for supplying power to said brush scrubbers;

scrubbing the semiconductor substrates in said scrubbing modular singularly, wherein;

each said semiconductor substrate has a surface thereon with an interface of polysilicon and silicon oxide; and

an oxide is formed on the polysilicon during said scrubbing;

removing the semiconductor substrates from said scrubbing module of said integrated cleaner with scrubber; and

loading the semiconductor substrates into said holder, thereby forming said batch of the semiconductor substrates.

48. The method as defined in claim 47, further comprising:

placing said batch of the semiconductor substrates into a wet receive tank;

moving said batch of the semiconductor substrates from said wet receive tank into the cleaning module within said integrated cleaner with scrubber without having removed the semiconductor substrates from said integrated cleaner with scrubber, the semiconductor substrates being singularly positioned within said scrubber module;

removing, within the cleaning module, the oxide from the polysilicon of the interface on the surface of each of the semiconductor substrates and loading the semiconductor substrates into a drying module without having removed the semiconductor substrates from said integrated cleaner with scrubber, the semiconductor substrates being singularly positioned within said scrubber module; and

drying, in the drying module, the semiconductor substrates without oxidizing the polysilicon of the interface on the surface of each of the semiconductor substrates, wherein said integrated cleaner with scrubber further comprises said wet receive tank and said drying module.

49. The method as defined in claim 48, wherein removing the oxide from the polysilicon of the interface on the surface of each of the semiconductor substrates is performed using a cleaning solution selected from the group consisting of hydrofluoric acid, a solution of ammonium fluoride and hydrofluoric acid, and a solution of hydrofluoric acid and tetramethylammonium hydroxide.

50. The method as defined in claim 48, wherein said drying is a process selected from the group consisting of a Marangoni dryer process and an IPA dryer process.

51. The method as defined in claim 48, further comprising, after said drying:

forming an electrically conductive material upon the polysilicon of the interface on the surface of each of the semiconductor substrates.

52. The method as defined in claim 47, further comprising:

a deionized rinse of said one of said plurality of semiconductor substrates after scrubbing each said semiconductor substrate in said scrubbing module singularly.