Plasma processes for depositing low dielectric constant films

• US 6,596,655 B1
• Filed: 09/19/2001
• Issued: 07/22/2003
• 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): GHYKA, ALEXANDER G
• Application Number:
  US09/957,681
• Time in Patent Office: 671 Days
• Field of Search: 438/758, 438/787, 438/788, 438/789, 438/790, 427/489, 427/492, 427/497, 427/503, 427/509, 427/249.15
• 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 21/02164 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, 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 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 a compound with an oxidizing gas while applying RF power to deposit the low dielectric constant film on the semiconductor substrate, wherein the compound comprises the general formula

and wherein the low dielectric constant film has a dielectric constant of about 3 or less and retains sufficient silicon-carbon bonds to have a carbon content from about 1% to about 50% by atomic weight.

2. The method of claim 1 wherein the compound is selected from the group consisting of disilanomethane, bis(methylsilano)methane, 1,3,5-trisilano-2,4,6-trimethylene, 2,2-disilanopropane, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 2,4,6-trisilanetetrahydropyran, 2,2-bis(1-methyldisiloxanyl)propane, fluorinated carbon derivatives thereof, and combinations thereof.

3. The method of claim 1, wherein the compound is selected from the group consisting of disilanomethane, bis(methylsilano)methane, 1,3,5-trisilano-2,4,6-trimethylene, 1,3-bis(silanomethylene)disiloxane, bis(1-methyldisiloxanyl)methane, 1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene, 2,4,6-trisilanetetrahydropyran, fluorinated carbon derivatives thereof, and combinations thereof.

4. The method of claim 1, wherein the oxidizing gas is selected from the group consisting of oxygen, nitrous oxide, ozone, carbon dioxide, and water.

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

6. The method of claim 1, wherein the substrate is maintained at a temperature of from about −

20°

C. to about 400°

C. during the deposition of the film.

7. The method of claim 1, wherein the compound and the oxidizing gas are reacted in the presence of a gas selected from the group consisting of helium and argon.

8. The method of claim 1, wherein the frequency of the RF power is about 13.56 MHz.

9. The method of claim 1, wherein the compound and the oxidizing gas are reacted at a RF power level between about 10 W and about 500 W.

10. A method for depositing a low dielectric constant film on a semiconductor substrate, comprising reacting a compound with an oxidizing gas while applying RF power to deposit the low dielectric constant film on the semiconductor substrate, wherein the compound comprises the general formula

and wherein the low dielectric constant film has a dielectric constant of about 3 or less and retains sufficient silicon-carbon bonds to have a carbon content from about 1% to about 50% by atomic weight.

11. The method of claim 10, wherein the compound is selected from the group consisting of 1,2-disilanoethane, 2,5-disilanetetrahydrofuran, 1,2-bis(methylsilano)ethane, fluorinated carbon derivatives thereof, and combinations thereof.

12. The method of claim 10, wherein the compound and the oxidizing gas are reacted at a RF power level between about 10 W and about 500 W.

13. The method of claim 10, wherein the compound and the oxidizing gas are reacted at a pulsed RF power level from about 20 W to about 500 W.

14. A method for depositing a low dielectric constant film on a semiconductor substrate, comprising reacting a compound with an oxidizing gas while applying RF power to deposit the low dielectric constant film on the semiconductor substrate, wherein the compound comprises the general formula

and wherein the low dielectric constant film has a dielectric constant of about 3 or less and retains sufficient silicon-carbon bonds to have a carbon content from about 1% to about 50% by atomic weight.

15. The method of claim 14, wherein the oxidizing gas is selected from the group consisting of nitrous oxide, ozone, carbon dioxide, and water.

16. The method of claim 14, wherein the oxidizing gas is oxygen.

17. The method of claim 14, wherein the substrate is maintained at a temperature of from about −

20°

C. to about 400°

C. during the deposition of the film.

18. The method of claim 14, wherein the compound and the oxidizing gas are reacted in the presence of a gas selected from the group consisting of helium and argon.

19. The method of claim 14, wherein the frequency of the RF power is about 13.56 MHz.

20. The method of claim 14, wherein the compound and the oxidizing gas are reacted at a RF power level between about 10 W and about 500 W.