Method of patterning a film

• US 20050266692A1
• Filed: 06/01/2004
• Published: 12/01/2005
• Est. Priority Date: 06/01/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Shah, Uday, Chau, Robert S., Doyle, Brian S., Brask, Justin K.
• Granted Patent: US 7,579,280 B2
• Time in Patent Office: Days
• US Class Current: 438/717
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 29/785 having a channel with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

A method of patterning a thin film. The method includes forming a mask on a film to be patterned. The film is then etched in alignment with the mask to form a patterned film having a pair of laterally opposite sidewalls. A protective layer is formed on the pair of laterally opposite sidewalls. Next, the mask is removed from above the patterned film. After removing the mask from the patterned film, the protective layer is removed from the sidewalls.

Claims

1. A method of patterning a film comprising:

forming a mask above a film to be patterned;

etching said film in alignment with said mask to form a patterned film having a pair of laterally opposite sidewalls;

forming a protective layer on said pair of laterally opposite sidewalls;

after forming said protective layer, removing said mask from above said patterned film; and

after removing said mask from said patterned film, removing said protective layer from said sidewalls.

2. The method of claim 1 further comprising prior to forming said mask on said film to be patterned, forming a protective layer on the top surface of said film to be patterned.

3. The method of claim 1 wherein said film is a semiconductor film

4. The method of claim 3 wherein said semiconductor film is a monocrystalline silicon film.

5. The method of claim 4 wherein said mask is a silicon nitride film.

6. The method of claim 5 wherein said protective layer on said sidewalls is a silicon dioxide film.

7. The method of claim 6 wherein said protective layer is formed by exposing said silicon film to a solution comprising hydrogen peroxide.

8. The method of claim 6 wherein said mask is removed with a wet etchant comprising phosphoric acid and water.

9. A method of patterning a semiconductor film comprising:

forming a masking layer above a semiconductor film formed on a substrate;

patterning said masking layer into a mask;

etching said semiconductor film in alignment with said mask to form a semiconductor body having a pair of laterally opposite sidewalls;

forming a protective layer on said sidewalls of said semiconductor body;

after forming said protective layer, removing said mask from above said semiconductor body; and

after removing said mask from said semiconductor body, removing said protective layer on said sidewalls of said semiconductor body.

10. The method of claim 9 wherein said mask is a silicon nitride or silicon oxynitride film and wherein said mask is removed utilizing a wet etchant comprising phosphoric acid and DI water.

11. The method of claim 9 wherein said semiconductor film is a doped single crystalline silicon film.

12. The method of claim 11 wherein said protective layer on said sidewalls is a silicon dioxide film.

13. The method of claim 12 wherein said silicon dioxide film is grown by exposing said doped single crystalline silicon film to an aqueous solution comprising a peroxide.

14. The method of claim 13 wherein said silicon dioxide film grown by exposing said sidewalls to an ageous solution comprising between 3-12% by volume of unstabilized hydrogen peroxide.

15. The method of claim 12 wherein said silicon dioxide is formed by exposing said doped single crystalline film to ozone.

16. The method of claim 9 wherein said semiconductor film is selected from the group consisting of silicon, gallium arsenide, germanium, germanium silicon, InSb, and InP.

17. The method of claim 9 further comprising forming a gate dielectric layer on said sidewalls of said semiconductor body and forming a gate electrode over and around said semiconductor body and adjacent to said gate dielectric layer on said sidewalls of said semiconductor body.

18. A method of forming a nonplanar transistor comprising:

doping a single crystalline silicon film formed on a substrate;

forming a silicon nitride layer over said doped single crystalline silicon film;

patterning said silicon nitride layer into a silicon nitride hard mask;

etching said doped single crystalline silicon film in alignment with said silicon nitride hard mask to define a doped single crystalline silicon body having a pair of laterally opposite sidewalls;

growing a silicon dioxide film on said sidewalls of said doped single crystalline silicon film;

removing said silicon nitride hard mask from above said doped single crystalline silicon body;

after removing said silicon nitride hard mask, removing said silicon dioxide film from said sidewalls of said doped single crystalline silicon body;

forming a gate dielectric layer on said pair of laterally opposite sidewalls and on the top surface of said doped single crystalline silicon body;

forming a gate electrode on said gate dielectric layer on said top surface of said doped single crystalline silicon body and adjacent to said gate dielectric layer on said sidewalls of said doped single crystalline silicon body; and

forming a pair of source/drain regions in said single crystalline silicon body on opposite sides of said gate electrode.

19. The method of claim 18 wherein said silicon dioxide film is grown by exposing said sidewalls to an aqueous solution comprising a peroxide.

20. The method of claim 19 wherein said peroxide is hydrogen peroxide.

21. The method of claim 20 wherein sonic energy is applied to said hydrogen peroxide while growing said silicon dioxide film.

22. The method of claim 18 wherein said silicon oxide film is approximately two mono-layers thick.

23. The method of claim 18 wherein said oxide is grown by exposing said sidewalls to a plasma or thermal oxidation process.

24. The method of claim 18 wherein said silicon nitride hard mask is removed utilizing a wet etchant comprising phosphoric acid and DI water.

25. The method of claim 24 wherein said wet etchant is heated to a temperature between 150-170°

C.

26. The method of claim 18 wherein said silicon dioxide film on said sidewalls is removed utilizing an aqueous solution comprising HF.

27. The method of claim 26 wherein said aqueous solution comprises between 0.5 to 2% HF and wherein said aqueous solution is less than room temperature.

28. The method of claim 18 wherein prior to forming said masking layer above said doped single crystalline silicon film, a silicon dioxide film is grown on said doped single crystalline silicon film and wherein said hard mask is formed on said silicon dioxide film grown on said doped single crystalline silicon film.

29. The method of claim 28 wherein removing said silicon dioxide film from said top surface of said doped single crystalline silicon film and removing said silicon dioxide film from said sidewalls.

30. A method of patterning a film comprising:

forming a masking material on a film to be patterned;

patterning said masking material into a mask;

etching said film with a first etchant which etches said film without significantly etching said masking material to form a patterned film having a pair of laterally opposite sidewalls;

forming a passivation layer on said sidewalls of said patterned film; and

removing said mask with a second etchant which does not significantly etch said passivation layer on said sidewalls, wherein said second etchant is capable of etching said film.

31. The method of claim 30 wherein said first etchant has a etch selectivity of said masking material to said film of at least 100:

1.

32. The method of claim 30 wherein said second etchant has a etch selectivity of said masking material to said sidewall passivation layer of at least 100:

1.

33. The method of claim 30 wherein said masking material is patterned into a mask utilizing a patterned photoresist film, and wherein said patterned photoresist film is removed prior to etching said film with said first etchant.

34. The method of claim 30 further comprising after removing said mask, removing said passivation layer from said sidewalls.