Very low dielectric constant plasma-enhanced CVD films

• US 20020197849A1
• Filed: 06/28/2002
• Published: 12/26/2002
• Est. Priority Date: 01/18/2000
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Mandal, Robert P.
• Granted Patent: US 6,596,627 B2
• Time in Patent Office: Days
• US Class Current: 438/633
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/56 After-treatment
• 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 21/02214 the compound comprising silicon and oxygen
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• 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: Y10T 428/249969 Of silicon-containing material [e.g., glass, etc.]
• CPC Class Codes: Y10T 428/249976 Voids specified as closed
• CPC Class Codes: Y10T 428/249978 Voids specified as micro
• CPC Class Codes: Y10T 428/249994 Composite having a component wherein a constituent is liquid or is contained within preformed walls [e.g., impregnant-filled, previously void containing component, etc.]

Abstract

The present invention provides a method for depositing nano-porous low dielectric constant films by reacting an oxidizable silicon containing compound or mixture comprising an oxidizable silicon component and an oxidizable non-silicon component having thermally liable groups with nitrous oxide, oxygen, ozone, or other source of reactive oxygen in gas-phase plasma-enhanced reaction. 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 low-density structure. The nano-porous silicon oxide based films are useful for forming layers 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 methylsilyl-1,4-dioxinyl ether or methylsiloxanyl furan and 2,4,6-trisilaoxane or cyclo-1,3,5,7-tetrasilylene-2,6-dioxy-4,8 dimethylene with nitrous oxide or oxygen followed by a cure/anneal that includes a gradual increase in temperature.

Claims

1. A method for depositing a dielectric layer, comprising:

reacting an organosilicon compound and a non-silicon compound comprising a cyclic ring at conditions sufficient to substantially retain the cyclic ring in an intermediate dielectric layer; and

substantially converting the cyclic ring to a dispersed void.

2. The method of claim 1, wherein the organosilicon compound comprises one or more silicon-carbon bonds.

3. The method of claim 2, wherein the non-silicon compound comprises a multiply unsaturated cycloalkene component having two carbon-carbon double bonds per cyclic ring.

4. The method of claim 3, wherein the multiply unsaturated cycloalkene components are selected from the group consisting of vinyl-1,4-dioxinyl ether, vinyl furyl ether, vinyl-1,4-dioxin, vinyl furan, methyl furoate, furyl formate, furyl acetate, furaldehyde, difuryl ketone, difuryl ether, difurfuryl ether, furan, 1,4-dioxin, fluorinated derivatives thereof, and combinations thereof.

5. The method of claim 1, wherein the organosilicon compound comprises the structure —

Si—

O—

Si—

.

6. The method of claim 5, wherein the organosilicon compound comprises a cyclic structure.

7. The method of claim 1, wherein the dispersed void is formed by annealing the substrate.

8. The method of claim 1, wherein the organosilicon compound is selected from the group consisting of methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 2,4,6-trisilaoxane cyclo-1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilacyclohexane, 1,3-dimethyidisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,1,5,5-tetramethyltrisiloxane, and 1,1,3,5,5-pentamethyltrisiloxane.

9. The method of claim 1, wherein the non-silicon compound comprising a cyclic ring further comprises an aliphatic group attached to the cyclic ring.

10. The method of claim 1, wherein reacting the organosilicon compound and the non-silicon compound comprises reacting the organosilicon compound and the non-silicon compound with an oxidizing gas.

11. The method of claim 10, wherein the oxidizing gas is selected from the group consisting of oxygen, nitrous oxide, ozone, carbon dioxide, and combinations thereof.

13. The method of claim 12, further comprising substantially converting the cyclic ring to a dispersed void.

14. The method of claim 13, wherein the dispersed void is formed by annealing the substrate.

15. The method of claim 12, wherein non-silicon compound comprises a multiply unsaturated cycloalkene selected from the group consisting of vinyl-1,4-dioxinyl ether, vinyl furyl ether, vinyl-1,4-dioxin, vinyl furan, methyl furoate, furyl formate, fury acetate, furaldehyde, difuryl ketone, difuryl ether, difurfuryl ether, furan, 1,4-dioxin, fluorinated derivatives thereof, and combinations thereof.

16. The method of claim 12, wherein the silicon compound is a cyclic siloxane.

17. The method of claim 12, wherein the silicon compound is selected from the group consisting of methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 2,4,6-trisilaoxane cyclo-1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilacyclohexane, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,1,5,5-tetramethyltrisiloxane, and 1,1,3,5,5-pentamethyltrisiloxane.

18. The method of claim 12, wherein reacting the organosilicon compound and the non-silicon compound comprises reacting the organosilicon compound and the non-silicon compound with an oxidizing gas.

19. The method of claim 18, wherein the oxidizing gas is selected from the group consisting of oxygen, nitrous oxide, ozone, carbon dioxide, and combinations thereof.

12. A method for depositing a dielectric layer, comprising:

reacting a silicon compound comprising one or more silicon-carbon bonds and a non-silicon compound comprising a cyclic ring having two carbon-carbon double bonds and an aliphatic group attached to the cyclic ring at conditions sufficient to substantially retain the cyclic ring in a dielectric layer.

20. A method for depositing a dielectric layer, comprising:

reacting a silicon compound comprising a silicon-carbon bond and a non-silicon compound comprising a cyclic ring at conditions sufficient to substantially retain the cyclic ring in an intermediate dielectric layer; and

substantially converting the cyclic ring to a dispersed void.

21. The method of claim 20, wherein the silicon compound is a cyclic siloxane.

22. The method of claim 20, wherein the non-silicon compound comprises a multiply unsaturated cycloalkene component having two carbon-carbon double bonds per cyclic ring.

23. The method of claim 22, wherein the multiply unsaturated cycloalkene component is selected from the group consisting of vinyl-1,4-dioxinyl ether, vinyl furyl ether, vinyl-1,4-dioxin, vinyl furan, methyl furoate, furyl formate, furyl acetate, furaldehyde, difuryl ketone, difuryl ether, difurfuryl ether, furan, 1,4-dioxin, fluorinated derivatives thereof, and combinations thereof.

24. The method of claim 20, wherein the dispersed void is formed by annealing the substrate.

25. The method of claim 20, wherein the silicon compound is selected from the group consisting of methylsilane, dimethylsilane, disilanomethane, bis(methylsilano)methane, 2,4,6-trisilaoxane cyclo-1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilacyclohexane, 1,3-dimethyidisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,1,5,5-tetramethyltrisiloxane, and 1,1,3,5,5-pentamethyltrisiloxane.

26. The method of claim 20, wherein the non-silicon compound comprising a cyclic ring further comprises an aliphatic group attached to the cyclic ring.

27. The method of claim 20, wherein reacting the organosilicon compound and the non-silicon compound comprises reacting the organosilicon compound and the non-silicon compound with an oxidizing gas.

28. The method of claim 27, wherein the oxidizing gas is selected from the group consisting of oxygen, nitrous oxide, ozone, carbon dioxide, and combinations thereof.