Process for depositing a SiO.sub.x film having reduced intrinsic stress and/or reduced hydrogen content

• US 5,750,211 A
• Filed: 07/16/1993
• Issued: 05/12/1998
• Est. Priority Date: 05/17/1991
• Status: Expired due to Term

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Weise, Mark, Denison, Dean R.
• Primary Examiner(s): King, Roy V.
• Application Number:
  US08/106,768
• Time in Patent Office: 1,761 Days
• Field of Search: 427/38, 427/39, 427/255.3, 427/579, 427/571, 427/575, 427/573, 427/574, 156/643, 156/646, 437/228, 438/788, 438/787
• US Class Current: 427/579
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/44 characterised by the method of coating C23C16/04 takes precedence

Abstract

A process for reducing intrinsic stress and/or hydrogen content of a SiO_x film grown by ECR chemical vapor deposition, wherein a vapor phase etchant is introduced while growing the silicon dioxide film. The presence of the etchant during the plasma deposition process allows for selective removal of high energy silicon dioxide molecules in the growing film thus reducing intrinsic stress within the film. The use of halogen etchants further reduces the amount of hydrogen present as hydroxyl within the film.

Claims

1. An ECR CVD process for growing a SiO_x , film having reduced intrinsic stress. comprising the steps of:

providing a substrate in a reaction zone of an ECR CVD reactor;

simultaneously introducing first, second and third gases into the reaction zone, the first gas being a carbon-free silicon containing gas and the third gas consisting essentially of oxygen;

growing the film on the substrate by decomposing the first gas and reacting the decomposed gas on a surface of the substrate, the growing film comprising atoms in ordered and disordered crystallographic states; and

reducing intrinsic stress in the film by removing atoms from the growing film in the disordered crystallographic state, the disordered atoms being removed by reacting a chemically active species of the second gas with the growing film, the second gas being a carbon-free halogen containing gas and the film growing and intrinsic stress reducing steps being performed simultaneously, the film growing and intrinsic stress reducing steps being performed under ECR condition in a vacuum environment.

2. The process of claim 1, wherein the first gas is different from the second gas.

3. The process of claim 1, wherein the film consists essentially of silicon dioxide.

4. The process of claim 1, wherein the first gas comprises a gas selected from the group consisting of SiH₄, Si₂ H₆, SiF₄, Si₂ F₆, SiCl₄ and SiH₂ cl₂.

5. The process of claim 3, wherein the third gas in pure oxygen.

6. The process of claim 1, wherein the second gas comprises a halogen gas selected from the group consisting of NF₃, HF, SF₆ Br₂, Cl₂, F₂ and I₂.

7. The process of claim 1 wherein the vacuum is below 0.05 Torr and the substrate is maintained at a temperature below about 450°

C.

8. The process of claim 1, wherein the intrinsic stress reducing step reduces a magnitude of intrinsic stress in the film to no greater than a range of 100 to 200 MPa.

9. The process of claim 1, wherein the second gas comprises a fluorine containing etchant.

10. The process of claim 9, wherein the fluorine-containing etchant is introduced to the reaction zone at an atomic ratio of F:

Si of between 1;

10 to 4;

1.

11. The process of claim 1, wherein the film is deposited on a silicon wafer.

12. The process of claim 11, wherein the silicon wafer includes an exposed metallization layer and the SiO_X film is applied as a dielectric layer on the silicon wafer.

13. The process of claim 1, wherein at least one of the first and second gases contains hydrogen and the intrinsic stress reducing step results in reducing hydrogen content in the film.

14. The process of claim 13, wherein the intrinsic stress reducing step reduces hydrogen in the form of hydroxyl in the film to no greater than a range of 1.5 to 3 at. %.

15. The process of claim 1, wherein the intrinsic stress reducing step etches the film at a rate of 20 to 90% of a rate at which the film is grown during the film growing step.

16. An ECR CVD process for growing a SiO_X film having reduced hydrogen content, comprising the steps of:

providing a substrate in a reaction zone of an ECR CVD reactor;

simultaneously introducing first, second and third gases into the reaction zone, the first gas being a carbon-free silicon containing gas and at least one of the first and second eases containing hydrogen, the third gas consisting essentially of oxygen;

growing the film on the substrate by decomposing the first gas and reacting the decomposed gas on a surface of the substrate, the film including hydrogen atoms therein; and

removing the hydrogen atoms from the film by reacting the growing film with a chemically active species in the second gas, the second gas being a carbon-free halogen containing gas and the film growing and hydrogen removing steps being performed simultaneously, the film growing and hydrogen removing steps being performed under ECR condition in a vacuum environment.

17. The process of claim 16, wherein the first gas is different than the second gas.

18. The process of claim 16, wherein the film consists essentially of silicon dioxide.

19. The process of claim 16, wherein the first gas comprises a gas selected from the group consisting of SiH₄, Si₂ H₆, SiF₄, Si₂ F₆, SiCl₄ and SiH₂ Cl₂.

20. The process of claim 18, wherein the third gas is pure oxygen.

21. The process of claim 16, wherein the second gas comprises a halogen gas selected from the group consisting of NF₃, HF, SF₆ Br₂, Cl₂, F₂ and I₂.

22. The process of claim 16, wherein the vacuum is below 0.05 Torr and the substrate is maintained at a temperature below about 450°

C.

23. The process of claim 16, wherein the hydrogen removing step reduces a magnitude of intrinsic stress in the film to no greater than a range of 100 to 200 MPa.

24. The process of claim 16, wherein the second gas comprises a fluorine-containing etchant.

25. The process of claim 24, wherein the fluorine-containing etchant is introduced to the reaction zone at an atomic ratio of F:

Si of 1;

10 to 4;

1.

26. The process of claim 18, wherein the film is deposited on a silicon wafer.

27. The process of claim 26, wherein the silicon wafer includes an exposed metallization layer and the SiO_X film is applied as a dielectric layer on the silicon wafer.

28. The process of claim 16, wherein the hydrogen reducing step reduces hydrogen in the form of hydroxyl in the film to no greater than a range of 1.5 to 3 at. %.

29. The process of claim 16, wherein the hydrogen reducing step etches the film at a rate of 20 to 90% of a deposition rate of the film during the film growing step.