METHOD AND SYSTEM FOR GROWING A THIN FILM USING A GAS CLUSTER ION BEAM

• US 20090317564A1
• Filed: 06/24/2008
• Published: 12/24/2009
• Est. Priority Date: 06/24/2008
• Status: Active Grant

• Current Assignee: TEL Manufacturing and Engineering of America, Inc.
• Original Assignee: TEL Epion Inc. (Tokyo Electron Limited)
• Inventors: Shao, Yan, Hautala, John J., Graf, Michael, Freer, Brian S.
• Granted Patent: US 9,103,031 B2
• Time in Patent Office: Days
• US Class Current: 427/563
• CPC Class Codes: C23C 14/10 Glass or silica
• CPC Class Codes: C23C 14/221 Ion beam deposition C23C14/46, C23C14/48 take precedence
• CPC Class Codes: C23C 14/48 Ion implantation
• CPC Class Codes: H01J 2237/0812 Ionized cluster beam [ICB] sources
• CPC Class Codes: H01J 27/026 Cluster ion sources

Abstract

A method of forming a thin film on a substrate is described. The method comprises providing a substrate in a reduced-pressure environment, and generating a gas cluster ion beam (GCIB) in the reduced-pressure environment from a pressurized gas mixture. A beam acceleration potential and a beam dose are set to achieve a thickness of the thin film ranging up to about 300 angstroms and to achieve a surface roughness of an upper surface of the thin film that is less than about 20 angstroms. The GCIB is accelerated according to the beam acceleration potential, and the accelerated GCIB is irradiated onto at least a portion of the substrate according to the beam dose. By doing so, the thin film is grown on the at least a portion of the substrate to achieve the thickness and the surface roughness.

Claims

1. A method of forming a thin film on a substrate, comprising:

providing a substrate in a reduced-pressure environment;

generating a gas cluster ion beam (GCIB) in said reduced-pressure environment from a pressurized gas mixture;

selecting a beam acceleration potential and a beam dose to achieve a thickness of said thin film and to achieve a surface roughness of an upper surface of said thin film;

accelerating said GCIB according to said beam acceleration potential;

irradiating said accelerated GCIB onto at least a portion of said substrate according to said beam dose; and

growing said thin film on said at least a portion of said substrate to achieve said thickness and said surface roughness.

2. The method of claim 1, wherein said thickness of said thin film ranges up to about 300 angstroms and said surface roughness is less than about 20 angstroms.

3. The method of claim 1, wherein said pressurized gas mixture comprises oxygen and an optional inert gas, and wherein said at least a portion of said substrate comprises silicon, and wherein said grown thin film comprises SiO₂.

4. The method of claim 3, wherein said beam acceleration potential ranges up to 100 kV, and wherein said beam dose ranges up to about 1×

10¹⁶ clusters per cm².

5. The method of claim 3, wherein said beam acceleration potential ranges up to 10 kV and wherein said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 140 angstroms and said surface roughness ranges up to about 8 angstroms.

6. The method of claim 3, wherein said beam acceleration potential ranges up to 7 kV and wherein said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 115 angstroms and said surface roughness ranges up to about 7 angstroms.

7. The method of claim 3, wherein said beam acceleration potential ranges up to 5 kV and wherein said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 80 angstroms and said surface roughness ranges up to about 6 angstroms.

8. The method of claim 3, wherein said beam acceleration potential ranges up to 3 kV and wherein said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 55 angstroms and said surface roughness ranges up to about 3 angstroms.

9. The method of claim 3, wherein said beam acceleration potential ranges up to 2 kV and wherein said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 25 angstroms and said surface roughness ranges up to about 2 angstroms.

10. The method of claim 3, further comprising:

modifying a beam energy distribution to change said thickness of said thin film, or said surface roughness of said thin film, or both.

11. The method of claim 10, wherein said modifying said beam energy distribution comprises broadening said beam energy distribution to decrease said surface roughness of said thin film, or narrowing said beam energy distribution to increase said surface roughness of said thin film.

12. The method of claim 10, wherein said modifying said beam energy distribution comprises directing said GCIB along a GCIB path through an increased pressure region such that at least a portion of said GCIB path traverses said increased pressure region.

13. The method of claim 10, wherein a pressure-distance integral along said at least a portion of said GCIB path is equal to or greater than about 0.005 torr-cm, said beam acceleration potential ranges up to 70 kV, and said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 70 angstroms and said surface roughness ranges up to about 1 angstrom.

14. The method of claim 10, wherein a pressure-distance integral along said at least a portion of said GCIB path is equal to or greater than about 0.002 torr-cm, said beam acceleration potential ranges up to 70 kV, and said beam dose ranges up to about 2×

10¹⁴ clusters per cm², and wherein said thickness ranges up to about 70 angstroms and said surface roughness ranges up to about 2 angstroms.

15. A method of forming a thin film on a substrate, comprising:

providing a substrate in a reduced-pressure environment;

generating a gas cluster ion beam (GCIB) in said reduced-pressure environment from a pressurized gas mixture;

selecting a beam acceleration potential and a beam dose to achieve a thickness of said thin film and to achieve a surface roughness of an upper surface of said thin film;

accelerating said GCIB according to said beam acceleration potential;

modifying a beam energy distribution for said GCIB;

irradiating said modified, accelerated GCIB onto at least a portion of said substrate according to said beam dose; and

growing said thin film on said at least a portion of said substrate to achieve said thickness and said surface roughness.

16. The method of claim 15, wherein said pressurized gas mixture comprises an oxygen-containing gas, a nitrogen-containing gas, a carbon-containing gas, a hydrogen-containing gas, a silicon-containing gas, or a germanium-containing gas, or a combination of two or more thereof.

17. The method of claim 15, wherein said pressurized gas mixture comprises O₂, N₂, NO, NO₂, N₂O, CO, or CO₂, or any combination of two or more thereof.

18. The method of claim 15, wherein said modifying said beam energy distribution comprises broadening said beam energy distribution to decrease said surface roughness of said thin film, or narrowing said beam energy distribution to increase said surface roughness of said thin film.

19. The method of claim 15, wherein said modifying said beam energy distribution comprises directing said GCIB along a GCIB path through an increased pressure region such that at least a portion of said GCIB path traverses said increased pressure region.

20. The method of claim 19, wherein a pressure-distance integral along said at least a portion of said GCIB path is equal to or greater than about 0.0001 torr-cm.

21. The method of claim 15, wherein said modifying said beam energy distribution comprises modifying a charge state of said GCIB.

22. A method of forming a thin film on a substrate, comprising:

optionally treating a surface of said substrate to remove residue or other contaminants;

growing a thin film on at least a portion of said surface of said substrate by irradiating said substrate with a gas cluster ion beam (GCIB) formed from a pressurized gas mixture; and

annealing said thin film.

23. The method of claim 22, wherein said thin film comprises a thin oxide film, and wherein said pressurized gas mixture comprises oxygen and an optional inert gas.

24. The method of claim 22, further comprising:

adjusting any one or more of said optional treating step, said growing step, or said annealing step to alter a film thickness, a film roughness, or a film property, or any combination of two or more thereof.

25. The method of claim 22, wherein said annealing comprises elevating a temperature of said substrate to a value greater than or equal to about 800 degrees C.