Plasma processes for depositing low dielectric constant films

• US 6,562,690 B1
• Filed: 06/13/2000
• Issued: 05/13/2003
• Est. Priority Date: 02/11/1998
• Status: Expired due to Fees

• 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): COLEMAN, WILLIAM D
• Application Number:
  US09/594,186
• Time in Patent Office: 1,064 Days
• Field of Search: 438/400, 438/404, 438/431, 438/437, 438/478, 438/485, 438/507, 438/763, 438/772, 438/774, 438/780
• US Class Current: 438/400
• 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 21/02164 the material being a silicon oxide, e.g. SiO2
• 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 21/02211 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
• CPC Class Codes: Y10T 428/24926 : including ceramic, glass, porcelain or quartz layer
• 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 10W to about 200W or a pulsed RF power level from about 20W to about 500W. 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, or dimethylsilane, (CH₃)₂SiH₂, and nitrous oxide, N₂O, at a constant RF power level from about 10W to about 150W, or a pulsed RF power level from about 20W to about 250W during 10% to 30% of the duty cycle.

Claims

1. A method for depositing a low dielectric constant film on a semiconductor substrate, comprising reacting two or more silicon compounds with an oxidizing gas at plasma conditions sufficient to deposit a low dielectric constant film on the semiconductor substrate, wherein each of the two or more silicon compounds comprises a silicon-carbon bond and at least one of the two or more silicon compounds comprises oxygen, and 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 the low dielectric constant film has a carbon content from about 5% to about 30% by atomic weight.

3. The method of claim 1, wherein the low dielectric constant film has a carbon content from about 5% to about 10% by atomic weight.

4. The method of claim 1, wherein the conditions comprise a power density ranging from about 0.1 W/cm² to about 0.3 W/cm².

5. The method of claim 1, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.

6. The method of claim 1, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 40°

C.

7. The method of claim 1, wherein the oxidizing gas comprises oxygen.

8. The method of claim 7, wherein the oxidizing gas is oxygen.

9. The method of claim 1, wherein one of the two or more silicon compounds is 2,4,6,8-tetramethylcyclotetrasiloxane or trimethylsilane.

10. The method of claim 1, wherein at least one of the two or more silicon compounds comprises a silicon-hydrogen bond.

11. The method of claim 1, wherein the two or more silicon compounds are selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, dimethylsilanediol, ethylsilane, phenylsilane, diphenylsilane, diphenylsilanediol, methylphenylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, hexamethyidisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyidisiloxanyl) methane, 2,2-bis(1-methyldisiloxanyl)propane, 2,4,6,8-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, 2,4,6,8,10-pentamethylcyclopentasiloxane, and 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene.

12. The method of claim 1, wherein the low dielectric constant film is annealed at a substrate temperature from about 200°

C. to about 450°

C.

13. A method for depositing a low dielectric constant film on a semiconductor substrate, comprising reacting an organosiloxane compound comprising two oxygen atoms bonded to each silicon atom and one or two carbon atoms bonded to each silicon atom and an organosilane compound comprising from one to three carbon atoms bonded to each silicon atom with an oxidizing gas at plasma conditions sufficient to deposit a dielectric film on a substrate, wherein the dielectric film comprises carbon-silicon bonds and a dielectric constant of about 3 or less.

14. The method of claim 13, wherein the organosiloxane compound is octamethylcyclotetrasiloxane and the organosilane compound is trimethylsilane.

15. The method of claim 13, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.

16. The method of claim 13, wherein the dielectric film has a carbon content from about 5% to about 30% by atomic weight.

17. The method of claim 13, wherein the dielectric film has a carbon content from about 5% to about 10% by atomic weight.

18. The method of claim 13, wherein the conditions comprise a power density less than 1 W/cm².

19. The method of claim 13, wherein the dielectric film is annealed at a substrate temperature from about 200°

C. to about 450°

C.

20. The method of claim 13, wherein the organosiloxane compound is 2,4,6,8-tetramethylcyclotetrasiloxane.

21. A method for depositing a low dielectric constant film on a semiconductor substrate, comprising reacting two or more silicon compounds with an oxidizing gas at plasma conditions sufficient to deposit a dielectric film on a substrate, wherein each of the two or more silicon compounds comprises a silicon-carbon bond and a silicon-hydrogen bond, and wherein the dielectric film comprises carbon-silicon bonds and a dielectric constant of about 3 or less.

22. The method of claim 21, wherein the two or more silicon compounds are selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, ethylsilane, phenylsilane, diphenylsilane, methylphenylsilane, disilanomethane, bis(methylsilano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-dimethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,3-bis(silanomethylene)disiloxane, bis(1 -methyldisiloxanyl)methane, 2,2-bis(1-methyldisiloxanyl)propane, 2,4,6,8-tetramethylcyclotetrasiloxane, 2,4,6,8,10-pentamethylcyclopentasiloxane, and 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene.

23. The method of claim 21, wherein the plasma conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.

24. The method of claim 21, wherein the dielectric film has a carbon content from about 5% to about 30% by atomic weight.

25. The method of claim 21, wherein the dielectric film has a carbon content from about 5% to about 10% by atomic weight.

26. The method of claim 21, wherein the plasma conditions comprise a power density less than 1 W/cm².