Plasma processes for depositing low dielectric constant films

• US 6,930,061 B2
• Filed: 08/26/2003
• Issued: 08/16/2005
• Est. Priority Date: 02/11/1998
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lu, Yung-Cheng, Cheung, David, Barnes, Michael, Ishikawa, Tetsuya, Jeng, Shin-Puu, Yau, Wai-Fan, Mandal, Robert P., Poon, Tze Wing, Liu, Kuo-Wei, Willecke, Ralf B., Moghadam, Farhad
• Primary Examiner(s): Le, Thao P.
• Application Number:
  US10/648,616
• Publication Number:
  US 20040038545A1
• Time in Patent Office: 721 Days
• Field of Search: 438/780, 438/789, 438/790
• US Class Current: 438/789
• 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 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02208 the precursor containing a compound comprising Si
• 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
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A method and apparatus for depositing a low dielectric constant film by reaction of an organosilicon compound and an oxidizing gas at a constant RF power level from about 10 W to about 200 W or a pulsed RF power level from about 20 W to about 500 W. Dissociation of the oxidizing gas can be increased prior to mixing with the organosilicon compound, preferably within a separate microwave chamber, to assist in controlling the carbon content of the deposited film. 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 and 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, dimethylsilane, (CH₃)₂SiH₂, or 1,1,3,3-tetramethyl-disiloxane, (CH₃)₂—SiH—O—SiH—(CH₃)₂, and nitrous oxide, N₂O, at a constant RF power level from about 10 W to about 150 W, or a pulsed RF power level from about 20 W to about 250 W during 10% to 30% of the duty cycle.

Claims

1. A method for depositing a low dielectric constant film on a substrate, comprising reacting two or more organosiloxanes selected from the group consisting of 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran while applying RF power, wherein the low dielectric constant film comprises silicon-carbon bonds and a dielectric constant of about 3 or less.

2. The method of claim 1, wherein at least one of the organosiloxanes is cyclic and comprises C, H, and O.

3. The method of claim 2, wherein the cyclic organosiloxane comprising C, H, and O is 1,3,5,7-tetramethylcyclotetrasiloxane.

4. The method of claim 1, wherein the two or more organosiloxanes are reacted with an oxidizing gas.

5. The method of claim 4, wherein the oxidizing gas is selected from the group consisting of oxygen, ozone, nitrous oxide, carbon dioxide, and water.

6. The method of claim 1, wherein the RF power is pulsed to increase the porosity of the film.

24. The method of claim 1, wherein the reacting the two or more organosiloxanes comprises reacting the two or more organosiloxanes with N₂O in the presence of a gas selected from the group consisting of He, Ar, Ne, and nitrogen.

7. A method for depositing a low dielectric constant film on a substrate, comprising reacting two or more organosiloxanes selected from the group consisting of 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 1,3,5-trisilanetetrahydropyran, and 2,5-disilanetetrahydrofuran while applying RF power, wherein the low dielectric constant film comprises silicon-carbon bonds and a dielectric constant of about 3 or less.

8. The method of claim 7, wherein at least one of the organosiloxanes is selected from the group consisting of 1,3,5-trisilanetetrahydropyran and 2,5-disilanetetrahydrofuran.

9. The method of claim 7, wherein the two or more organosiloxanes are reacted with an oxidizing gas while applying RF power.

10. The method of claim 9, wherein the oxidizing gas is selected from the group consisting of oxygen, ozone, nitrous oxide, carbon dioxide, and water.

11. The method of claim 7, wherein the RF power is pulsed to increase the porosity of the film.

12. A method for depositing a low dielectric constant film on a substrate, comprising reacting two or more organosiloxanes, wherein a first organosiloxane of the two or more organosiloxanes is cyclic and comprises C, H, and O and a ring comprising carbon and oxygen, and a second organosiloxane of the two or more organosiloxanes is selected from the group consisting of 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and 1,3,5,7,9-pentamethylcyclopentasiloxane, while applying RF power, wherein the low dielectric constant film comprises silicon-carbon bonds and a dielectric constant of about 3 or less.

13. The method of claim 12, wherein the first organosiloxane is selected from the group consisting of 1,3,5-trisilanetetrahydropyran, 2,5-disilanetetrahydrofuran, and 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene.

14. The method of claim 13, wherein the first organosiloxane is 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene.

15. The method of claim 12, wherein the two or more organosiloxanes are reacted with an oxidizing gas.

25. The method of claim 12, wherein the reacting the two or more organosiloxanes comprises reacting the two or more organosiloxanes with N₂O in the presence of a gas selected from the group consisting of He, Ar, Ne, and nitrogen.

16. A method for depositing a low dielectric constant film on a substrate, comprising plasma assisted reaction of a mixture comprising an oxidizing gas and a siloxane comprising

wherein the low dielectric constant film comprises silicon-carbon bonds and a dielectric constant of about 3 or less.

17. The method of claim 16, wherein the mixture further comprises a siloxane selected from the group consisting of 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 1,3,5,7,9-pentamethylcyclopentasiloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, and 2,5-disilanetetrahydrofuran.

18. The method of claim 16, wherein the siloxane is selected from the group consisting of 1,3-bis(silanomethylene)disiloxane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, and 1,3,5-trisilanetetrahydropyran.

19. The method of claim 16, wherein the siloxane is 1,3-bis(silanomethylene)disiloxane.

20. The method of claim 19, wherein the oxidizing gas is N₂O.

21. The method of claim 16, wherein the mixture further comprises an inert gas.

22. The method of claim 16, wherein the plasma is formed by RF power comprising high frequency RF power.

23. The method of claim 22, wherein the high frequency RF power is pulsed.