CVD nanoporous silica low dielectric constant films

• US 6,171,945 B1
• Filed: 10/22/1998
• Issued: 01/09/2001
• Est. Priority Date: 10/22/1998
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Cheung, David, Yau, Wai-Fan, Mandal, Robert P.
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): KILDAY, LISA A
• Application Number:
  US09/177,044
• Time in Patent Office: 810 Days
• Field of Search: 438/787, 438/790, 438/624, 438/622, 438/623
• US Class Current: 438/622
• 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 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• 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 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• 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

Abstract

A method and apparatus for depositing nano-porous low dielectric constant films by reaction of a silicon hydride containing compound or mixture optionally having thermally labile organic groups with a peroxide compound on the surface of a substrate. The deposited silicon oxide based film is annealed to form dispersed microscopic voids that remain in a nano-porous silicon oxide based film having a foam structure. The nano-porous silicon oxide based films are useful for filling gaps between metal lines with or without liner or cap layers. The nano-porous silicon oxide based films may also be used as an intermetal dielectric layer for fabricating dual damascene structures. Preferred nano-porous silicon oxide based films are produced by reaction of 1,3,5-trisilanacyclohexane, bis(formyloxysilano)methane, or bis(glyoxylylsilano)methane and hydrogen peroxide followed by a cure/anneal that includes a gradual increase in temperature.

Claims

1. A method for depositing a low dielectric constant film, comprising:

depositing a peroxide compound on a surface of a substrate;

reacting the deposited peroxide compound with a compound or mixture comprising thermally labile groups; and

annealing the substrate to form a silicon oxide based film;

whereby dispersed voids are formed in the silicon oxide based film.

2. The method of claim 1, wherein the compound or mixture comprising thermally labile groups comprises formyloxy (CH(O)—

O—

), glyoxylyl (CH(O)—

CO—

O—

), or formylcarbonyldioxy (CH(O)—

O—

CO—

O—

) groups.

3. The method of claim 2, wherein the compound or mixture comprising thermally labile groups comprises a compound selected from a group of bis(formyloxysilano)methane, bis(glyoxylylsilano)methane, bis(formylcarbonyldioxysilano)methane, 2,2-bis(formyloxysilano)propane, 1,2-bis(formyloxysilano)ethane, 1,2-bis(glyoxylylsilano)ethane, fluorinated bridging carbon derivatives thereof, and combinations thereof.

4. The method of claim 3, wherein the compound or mixture comprising thermally labile groups further comprises a non-silicon component selected from a group of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranylglyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride.

5. The method of claim 1, wherein the compound or mixture comprising thermally labile groups comprises:

a silicon compound selected from a group consisting of silane, methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilanacyclohexane, cyclo-1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3-dimethyl-disiloxane, 1,3-bis(silanomethylene)-disiloxane, bis(1-methyldisiloxanyl)methane, and 2,2-bis(1-methyldisiloxanyl)propane, and fluorinated carbon derivatives thereof; and

a non-silicon component selected from a group consisting of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranylglyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride.

6. The method of claim 1, wherein the compound or mixture comprising thermally labile groups comprises 1,3,5-trisilanacyclohexane, cyclo- 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, bis(formyloxysilano)methane, or bis(glyoxylylsilano)methane, or fluorinated bridging carbon derivatives thereof.

7. The method of claim 1, wherein the dispersed voids are formed by annealing the substrate with a temperature profile comprising a gradual rise to a final temperature of at least 400°

C.

8. The method of claim 1, wherein the compound or mixture comprising thermally labile groups has a non-planar ring structure.

20. The method of claim 1, wherein the compound or mixture having thermally labile groups comprises one or more silicon-hydrogen bonds.

21. The method of claim 1, further comprising depositing a conformal lining layer on the substrate prior to depositing the peroxide compound on the surface of the substrate.

22. The method of claim 1, wherein the thermally labile groups comprise oxygen.

43. The method of claim 1, wherein the compound or mixture comprising thermally labile groups comprises formyloxy (CH(O)—

O—

), glyoxylyl (CH(O)—

CO—

O—

), or formylcarbonyldioxy (CH(O)—

O—

CO—

O—

) groups.

9. A process for depositing a low dielectric constant film on a patterned metal layer on a substrate, comprising:

depositing a conformal lining layer on the patterned metal layer from process gases comprising one or more reactive silicon containing compounds;

depositing a peroxide compound on the conformal lining layer;

reacting the deposited peroxide compound with a compound or mixture having one or more thermally labile groups containing oxygen; and

annealing the substrate to form a silicon oxide based film;

whereby dispersed voids are formed in the silicon oxide based film.

10. The process of claim 9, wherein the compound or mixture having one or more thermally labile groups containing oxygen is selected from a group of bis(formyloxysilano)methane, bis(glyoxylyl-silano)methane, bis(formylcarbonyldioxysilano)methane, 2,2-bis(formyloxysilano)propane, 1,2-bis(formyloxysilano)ethane, and 1,2-bis(glyoxylylsilano)ethane, fluorinated bridging carbon derivatives thereof, and combinations thereof.

11. The process of claim 9, wherein the having one or more thermally labile groups containing oxygen further comprises a non-silicon component selected from a group of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranyl-glyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride.

12. The process of claim 9, wherein the compound or mixture having one or more thermally labile groups containing oxygen comprises:

a compound selected from a group of silane, methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilanacyclohexane, cyclo- 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3-dimethyldisiloxane, 1,3-bis(silanomethylene)-disiloxane, bis(1-methyldisiloxanyl)methane, and 2,2-bis(1 -methyldisiloxanyl)propane, and fluorinated carbon derivatives thereof, and

a non-silicon component selected from a group of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranylglyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride.

13. The process of claim 9, further comprising depositing a capping layer on the silicon oxide based film from process gases comprising the one or more reactive silicon containing compounds.

14. The process of claim 9, wherein the compound or mixture having one or more thermally labile groups containing oxygen comprises 1,3,5-trisilanacyclohexane, cyclo-1,3,5,7-tetrasilane-2,6-dioxy-4,8-dimethylene, bis(formyloxysilano)-methane, bis(glyoxylylsilano)methane, or fluorinated bridging carbon derivatives thereof.

15. The process of claim 9, wherein the dispersed voids are formed by annealing the substrate using a temperature profile that gradually rises to a final temperature of at least 400°

C.

16. The process of claim 9, wherein the compound or mixture having one or more thermally labile groups containing oxygen has a non-planar ring structure.

23. The method of claim 9, wherein the compound or mixture having thermally labile groups that comprise oxygen further comprise one or more silicon-hydrogen bonds.

26. The method of claim 15, wherein the silicon hydride containing compound or mixture further comprises a non-silicon component selected from a group consisting of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranylglyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride.

17. A method of forming a dual damascene structure, comprising:

depositing a peroxide compound on a surface of a substrate;

reacting the deposited peroxide compound with a compound or mixture comprising thermally labile groups; and

annealing the substrate to form a first silicon oxide based film, whereby dispersed voids are formed in the first silicon oxide based film;

depositing a low k etch stop on the first silicon oxide based film;

etching the low k etch stop to define a vertical interconnect opening that exposes the first silicon oxide based film;

depositing the peroxide compound on the low k etch stop and the exposed first silicon oxide based film;

reacting the deposited peroxide compound with the compound or mixture comprising thermally labile groups; and

annealing the substrate to form a second silicon oxide based film, whereby dispersed voids are formed in the second silicon oxide based film;

etching the second silicon oxide based film to define a horizontal interconnect that exposes the vertical interconnect opening in the low k etch stop; and

etching the first silicon oxide based film through the vertical interconnect opening to define a vertical interconnect.

18. The method of claim 17, wherein the first and the second silicon oxide based films comprise dispersed microscopic voids formed by annealing the substrate using a temperature profile that gradually rises to a final temperature of at least 400°

C.

19. The method of claim 17, wherein the first and the second silicon oxide based films comprise dispersed microscopic voids formed by reacting a deposited peroxide compound with a silicon hydride containing compound or mixture, wherein the silicon hydride containing compound or mixture has a non-planar ring structure.

24. A method for depositing a low dielectric constant film, comprising:

depositing a peroxide compound on a surface of a substrate;

reacting the deposited peroxide compound with a silicon hydride containing compound or mixture, wherein the silicon hydride containing compound or mixture comprises formyloxy (CH(O)—

O—

), glyoxylyl (CH(O)—

CO—

O—

), or formylcarbonyldioxy (CH(O)—

O—

CO—

O—

) groups; and

annealing the substrate to form a silicon oxide based film;

whereby dispersed voids are formed in the silicon oxide based film.

25. The method of claim 24, wherein the silicon hydride containing compound or mixture comprises a compound selected from a group of bis(formyloxysilano)methane, bis(glyoxylylsilano)methane, bis(formylcarbonyldioxysilano)methane, 2,2-bis(formyloxysilano)propane, 1,2-bis(fornyloxysilano)ethane, 1,2-bis(glyoxylylsilano)ethane, fluorinated bridging carbon derivatives thereof, and combinations thereof.

27. The method of claim 24, wherein the silicon hydride containing compound or mixture further comprises a non-silicon component selected from a group consisting of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranylglyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride.

28. The method of claim 24, wherein the dispersed voids are formed by annealing the substrate with a temperature profile comprising a gradual rise to a final temperature of at least 400°

C.

29. The method of claim 24, wherein the silicon hydride containing compound or mixture has a non-planar ring structure.

30. The method of claim 25, further comprising depositing a conformal lining layer on a patterned metal layer on a substrate from process gases comprising one or more reactive silicon containing compounds and an oxidizing gas.

31. The method of claim 27, further comprising depositing a conformal lining layer on a patterned metal layer on a substrate from process gases comprising one or more reactive silicon containing compounds and an oxidizing gas.

32. The method of claim 31, further comprising depositing a capping layer on the silicon oxide based film.

33. A method for depositing a low dielectric constant film, comprising:

depositing a peroxide compound on a surface of a substrate;

reacting the deposited peroxide compound with a silicon hydride containing compound or mixture, wherein the silicon hydride containing compound or mixture comprises;

a silicon compound selected from a group consisting of silane, methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilanacyclohexane, cyclo-1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3-dimethyl-disiloxane, 1,3-bis(silanomethylene)-disiloxane, bis(1-methyldisiloxanyl)methane, and 2,2-bis(1-methyldisiloxanyl)propane, and fluorinated carbon derivatives thereof; and

a non-silicon component selected from a group consisting of methyl maleic anhydride, 3-formyloxy-2,5-furandione, glycidaldehyde, oxiranylglyoxalate, dioxiranyl carbonate, dioxiranyl mesoxalate, and glycidic anhydride annealing the substrate to form a silicon oxide based film;

whereby dispersed voids are formed in the silicon oxide based film.

34. The method of claim 33, wherein the dispersed voids are formed by annealing the substrate with a temperature profile comprising a gradual rise to a final temperature of at least 400°

C.

35. The method of claim 33, wherein the silicon hydride containing compound or mixture has a non-planar ring structure.

36. The method of claim 33, further comprising depositing a conformal lining layer on a patterned metal layer on a substrate from process gases comprising one or more reactive silicon containing compounds and an oxidizing gas.

37. The process of claim 36, further comprising depositing a capping layer on the silicon oxide based film.

38. A method for depositing a low dielectric constant film, comprising:

depositing a peroxide compound on a surface of a substrate;

reacting the deposited peroxide compound with a silicon hydride containing compound or mixture, wherein the silicon hydride containing compound or mixture comprises 1,3,5-trisilanacyclohexane, cyclo-1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, bis(formyloxysilano)-methane, or bis(glyoxylylsilano)methane, or fluorinated bridging carbon derivatives thereof; and

annealing the substrate to form a silicon oxide based film;

whereby dispersed voids are formed in the silicon oxide based film.

39. The method of claim 38, wherein the dispersed voids are formed by annealing the substrate with a temperature profile comprising a gradual rise to a final temperature of at least 400°

C.

40. The method of claim 38, wherein the silicon hydride containing compound or mixture has a non-planar ring structure.

41. The method of claim 38, further comprising depositing a conformal lining layer on a patterned metal layer on a substrate from process gases comprising one or more reactive silicon containing compounds and an oxidizing gas.

42. The process of claim 41, further comprising depositing a capping layer on the silicon oxide based film.