CVD plasma assisted low dielectric constant films

• US 6,537,929 B1
• Filed: 05/25/2000
• Issued: 03/25/2003
• Est. Priority Date: 02/11/1998
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Cheung, David, Yau, Wai-Fan, Mandal, Robert R.
• Primary Examiner(s): GHYKA, ALEXANDER G
• Application Number:
  US09/580,505
• Time in Patent Office: 1,034 Days
• Field of Search: 438/790, 438/787, 438/788, 438/789, 427/489, 427/492, 427/497, 427/503, 427/509, 427/515, 427/579, 427/249.15, 427/255.37
• US Class Current: 438/790
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02208 the precursor containing a compound comprising Si
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/76808 involving intermediate temporary filling with material
• CPC Class Codes: H01L 21/7681 involving one or more buried masks
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76832 Multiple layers
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76835 Combinations of two or more different dielectric layers having a low dielectric constant H01L21/76832 takes precedence
• CPC Class Codes: H01L 2221/1031 Dual damascene by forming vias in the via-level dielectric prior to deposition of the trench-level dielectric

Abstract

A method and apparatus for depositing a low dielectric constant film by reaction of an organosilane or organosiloxane compound and an oxidizing gas at a low RF power level from 10-250 W. The oxidized organosilane or organosiloxane film has good barrier properties for use as a liner or cap layer adjacent other dielectric layers. The oxidized organosilane or organosiloxane film may also be used as an etch stop or an intermetal dielectric layer for fabricating dual damascene structures. The oxidized organosilane or organosiloxane films also provide excellent adhesion between different dielectric layers. A preferred oxidized organosilane film is produced by reaction of methylsilane, CH₃SiH₃, or dimethylsilane, (CH₃)₂SiH₂, and nitrous oxide, N₂O, at an RF power level from about 10 to 200 W or a pulsed RF power level from about 20 to 250 W during 10-30% of the duty cycle.

Claims

1. A method for depositing a low dielectric constant film, comprising reacting two or more organosilane or organosiloxane compounds with an oxidizing gas at an RF power level sufficient to deposit a film comprising carbon-silicon bonds and a dielectric constant less than about 3, wherein each of the organosilane or organosiloxane compounds has at least one silicon-hydrogen bond.

2. The method of claim 1, wherein the two or more organosilane or organosiloxane compounds have from one to two carbon atoms bonded to each silicon atom.

3. The method of claim 1, wherein the two or more organosilane or organosiloxane compounds are selected from a group consisting of methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilano-propane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-dimethyldisiloxane, 1,3-bis(silanomethylene)-disiloxane, bis(1-methyidisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)-propane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8,10-pentamethylcyclo-pentasiloxane, and 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene.

4. The method of claim 1, wherein the oxidizing gas is oxygen.

11. The method of claim 1, wherein the two or more organosilane or organosiloxane compounds are reacted at a substrate temperature from about −

20°

C. to about 400°

C.

12. The method of claim 1, wherein the two or more organosiloxane or organosilane compounds comprise both a cyclic organosiloxane compound and an organosilane compound.

13. The method of claim 1, wherein the two or more organosilane or organosiloxane compounds have from one to two methyl groups bonded to each silicon atom.

14. The method of claim 1, wherein the two or more organosilane or organosiloxane compounds comprise 2,4,6,8-tetramethylcyclotetrasiloxane.

15. The method of claim 1, wherein the two or more organosilane or organosiloxane compounds comprise at least one hydrogen atom bonded to each silicon atom.

16. The method of claim 15, wherein the two or more organosilane or organosiloxane compounds have one methyl group bonded to each silicon.

17. The method of claim 1, wherein the oxidizing gas and the two or more organosilane or organosiloxane compounds are reacted at a substrate temperature from about −

20°

C. to about 40°

C.

18. The method of claim 1, wherein the film is annealed.

19. The method of claim 1, wherein the RF power level provides a power density ranging from 0.05 W/cm² to 1000 W/cm².

20. The method of claim 1, wherein the RF power level provides a power density less than 1 W/cm².

21. The method of claim 1, wherein the RF power level is provided by a mixed frequency power source.

22. The method of claim 21, wherein the mixed frequency power source provides high frequency RF power at about 13.56 MHz and low frequency RF power about 360 KHz to about 1 MHz.

23. The method of claim 1, wherein a dielectric materal is deposited on the low dielectric constant film.

5. A process for depositing a low dielectric constant film, comprising:

depositing a conformal lining layer on a patterned metal layer on a substrate from process gases comprising two or more organosilane or organosiloxane compounds at an RF power level sufficient to provide the conformal lining layer with silicon-carbon bonds and a dielectric constant of about 3 or less, wherein each of the two or more organosilane or organosiloxane compounds has at least one silicon-hydrogen bond; and

depositing a gap-filling layer on the lining layer.

6. The method of claim 5, wherein the two or more organosilane or organosiloxane compounds have from one to two carbon atoms bonded to each silicon atom.

7. The process of claim 5, wherein the two or more organosilane or organosiloxane compounds are selected from a group consisting of methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilano-propane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-dimethyldisiloxane, 1,3-bis(silanomethylene)-disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyidisiloxanyl)-propane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8,10-pentamethylcyclopentasiloxane, and 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene.

8. The process of claim 5, wherein the two or more organosilane or organosiloxane compounds comprise from one to two methyl groups bonded to each silicon atom.

9. The process of claim 5, wherein the gap filling layer is deposited by reaction of a silano-containing compound and hydrogen peroxide.

10. The process of claim 5, further comprising depositing a capping layer on the gap filling layer from process gases comprising the two or more organosilane or organosiloxane compounds.

24. The method of claim 5, wherein the conformal lining layer is deposited at a substrate temperature from about −

20°

C. to about 400°

C.

25. The method of claim 5, wherein the conformal lining layer is deposited at a substrate temperature from about −

20°

C. to about 40°

C.

26. The method of claim 5, wherein the two or more organosiloxane or organosilane compounds comprise both a cyclic organosiloxane compound and an organosilane compound.

27. The method of claim 5, wherein the film is annealed at a substrate temperature from about 200°

C. to about 450°

C.

28. A method for depositing a low dielectric constant film on a semiconductor substrate, comprising reacting two or more organosilane or organosiloxane compounds with reactive oxygen atoms generated at RF plasma conditions sufficient to deposit a low dielectric constant film on the semiconductor substrate, wherein the two or more organosilane or organosiloxane compounds comprise at least one hydrogen atom bonded to each silicon and the low dielectric constant film has a dielectric constant of about 3 or less.

29. The method of claim 28, wherein the two or more organosilane or organosiloxane compounds have from one to two methyl groups bonded to each silicon atom.

30. The method of claim 28, wherein the two or more organosilane or organosiloxane compound comprise 2,4,6,8-tetramethylcyclotetrasiloxane.

31. The method of claim 28, wherein the two or more organosilane or organosiloxane compounds comprise at least one hydrogen atom bonded to each silicon atom.

32. The method of claim 28, wherein the two or more organosilane or organosiloxane compounds have one methyl group bonded to each silicon.

33. The method of claim 28, wherein the two or more organosilane or organosiloxane compounds comprise both a cyclic organosiloxane compound and an organosilane compound.

34. The method of claim 28, wherein the low dielectric constant film is annealed at a substrate temperature from about 200°

C. to about 450°

C.