Semiconductor device and method of manufacturing the same

1. A method of manufacturing a semiconductor device in which an insulating film is formed on a substrate, said method comprising the steps of:

(a) forming a low-pressure insulating film on the substrate, by converting a film-forming gas at a first gas pressure into a plasma and contacting the substrate with the plasma; and

(b) forming a high-pressure insulating film on said low-pressure insulating film, by converting said film-forming gas at a second gas pressure higher than the first gas pressure into a plasma and contacting said low-pressure insulating film with the plasma of said film-forming gas at the higher pressure; and

wherein said first gas pressure is in the range of 0.1 Torr to 1 Torr, and said second gas pressure is in the range of 1 Torr to 10 Torr.

2. The method of manufacturing a semiconductor device according to claim 1 ,

wherein parallel plate electrodes including a first electrode holding said substrate and a second electrode opposing said first electrode are used as means for forming said plasma,

wherein low-frequency electric power at a frequency of 100 kHz to 1 MHz is applied to said first electrode in step (a), and

wherein high-frequency electric power at 1 MHz or higher is applied to said second electrode in step (b).

3. The method of manufacturing a semiconductor device according to claim 2 ,

wherein said low-frequency electric power is applied to said first electrode in addition to application of said high-frequency electric power to said second electrode in the step of forming said high-pressure insulating film.

4. The method of manufacturing a semiconductor device according to claim 2 ,

wherein said high-frequency electric power is applied to said second electrode simultaneously in addition to application of said low-frequency electric power to said first electrode in the step of forming said low-pressure insulating film.

5. The method of manufacturing a semiconductor device according to claim 4 ,

wherein said low-frequency electric power is applied to said first electrode in addition to application of said high-frequency electric power to said second electrode in the step of forming said high-pressure insulating film.

6. The method of manufacturing a semiconductor device according to claim 1 ,

wherein parallel plate electrodes including a first electrode holding said substrate and a second electrode opposing said first electrode are used as means for forming said plasma,

wherein low-frequency electric power at a frequency of 100 kHz to 1 MHz is applied to said first electrode in step (a), and

wherein said low-frequency electric power is applied to said first electrode in step (b).

7. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas is composed of: an alkyl compound having a siloxane bond; and an oxygen-containing gas selected from the group consisting of N 2 O, H 2 O and CO 2 .

8. The method of manufacturing a semiconductor device according to claim 7 , wherein said alkyl compound having a siloxane bond is any one of hexamethyldisiloxane (HMDSO: (CH 3 ) 3 Si—O—Si(CH 3 ) 3 ), octamethylcyclotetrasiloxane (OMCTS: ((CH 3 ) 2 ) 4 Si 4 O 4 ,

and

tetramethylcyclotetrasiloxane (TMCTS: (CH 3 H) 4 Si 4 O 4

9. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas contains methylsilane.

10. The method of manufacturing a semiconductor device according to claim 9 , wherein said methyl silane is selected from the group consisting of monomethylsilane, dimethylsilane, trimethylsilane and tetramethylsilane.

11. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas contains methylcyclohexane or cyclohexane.

12. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas contains benzene.

13. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas contains methyl alcohol (CH 3 OH) or and ethyl alcohol (C 2 H 5 OH).

14. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas contains ammonia or nitrogen.

15. The method of manufacturing a semiconductor device according to claim 1 , wherein said film-forming gas contains a gas selected from the group consisting of helium (He), argon (Ar) and nitrogen (N 2 ).

16. The method of manufacturing a semiconductor device according to claim 1 wherein steps (a) and (b) are joined in succession into one continuous film deposition.

17. A method of manufacturing a semiconductor device in which an insulating film is formed on a substrate comprising:

converting a film-forming gas into a plasma, wherein said film-forming gas consists essentially of an alkyl compound having a siloxane bond, a hydrocarbon and an oxygen-containing gas selected from the group consisting of N 2 O, H 2 O and CO 2 ; and

contacting the plasma with the substrate to thereby form on the substrate an insulating film having a dielectric constant of 3 or less.

18. The method of manufacturing a semiconductor device according to claim 17 ,

wherein said alkyl compound having a siloxane bond is selected from the group consisting of hexamethyldisiloxane (HMDSO: (CH 3 ) 3 Si—O—Si(CH 3 ) 3 ), octamethylcyclotetrasiloxane

(OMCTS: ((CH 3 ) 3 ) 4 Si 4 O 4

 and

tetramethylcyclotetrasiloxane (TMCTS: (CH 3 H) 4 Si 4 O 4

19. The method of manufacturing a semiconductor device according to claim 17 ,

wherein said hydrocarbon (C x H y ) is selected from the group, consisting of acetylene (C 2 H 2 ), methylcyclohexane (CH 3 H 6 H 11 ), cyclohexane (C 6 H 12 ) and benzene (C 6 H 6 ).

20. The method of manufacturing a semiconductor device according to claim 17 ,

wherein said film-forming gas contains a gas selected from the group consisting of helium (He), argon (Ar) and nitrogen (N 2 ).

21. A method of manufacturing a semiconductor device comprising the steps of:

(a) forming an insulating film on a substrate by converting a film-forming gas which consists essentially of an alkyl compound having a siloxane bond, a hydrocarbon and oxygen-containing gas into a plasma and contacting the substrate with the plasma, wherein said oxygen-containing gas is selected from the group consisting of N 2 O, H 2 O and CO 2 ; and

(b) forming a barrier insulating film on the insulating film as formed in step (a).

22. A method of manufacturing a semiconductor device in which an insulating film is formed on a substrate, comprising:

(a) converting a film-forming gas into a plasma wherein said film-forming gas consists essentially of SiH n (CH 3 ) 4-n , wherein n=0, 1, 2 or 3, a hydrocarbon and an oxygen-containing gas selected from the group consisting of N 2 O, H 2 O and CO 2 ;

(b) contacting the plasma with the substrate to thereby form on the substrate an insulating film having a dielectric constant of 3 or less; and

(c) forming a barrier insulating film directly on the insulating film having a dielectric constant of 3 or less, as formed step (b).

23. The method of manufacturing a semiconductor device according to claim 22 ,

wherein said methylsilane (SiH n (CH 3 ) 4-n : n=0, 1, 2, 3) is selected from the group consisting of monomethylsilane (SiH 3 (CH 3 )), dimethylsilane (SiH 2 (CH 3 ) 2 ), trimethylsilane (SiH(CH 3 ) 3 ) and tetramethylsilane (Si(CH 3 ) 4 ).