Plasma processes for depositing low dielectric constant films

• US 6,660,656 B2
• Filed: 09/19/2001
• Issued: 12/09/2003
• 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): MEEKS, TIMOTHY HOWARD
• Application Number:
  US09/957,551
• Publication Number:
  US 20020045361A1
• Time in Patent Office: 811 Days
• Field of Search: 427/255.17, 427/255.29, 427/255-393, 427/255.6, 427/255.7, 438/761, 438/763, 438/778, 438/780, 438/783
• US Class Current: 438/761
• 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 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 process for depositing a low dielectric constant film, comprising reacting a fluorinated carbon derivative of one or more silicon compounds selected from a group consisting of fluorinated carbon derivatives of methylsilane, dimethylsilane, trimethylsilane, disilanomethane, bis(methyl-silano)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)di-siloxane, bis(1-methyldisiloxanyl)methane, 2,2-bis(1-methyl-disiloxanyl)propane, 2,4,6,8,10-pentamethylcyclopentasiloxane, 1,3,5,7-tetra-silano-2,6-dioxy-4,8-dimethylene, 2,4,6-trisilanetetrahydropyran, 2,5-disilanetetrahydrofuran, and combinations thereof with an oxidizing gas.

2. The process of claim 1, wherein the fluorinated carbon derivative is trifluoromethylsilane.

3. The process of claim 1, wherein the fluorinated carbon derivative is selected from a group consisting of trifluoromethylsilane, 1,2-disilanotetrafluoroethane, 1,2-bis(trifluoromethylsilano)tetrafluoroethane, 2,2-disilanohexafluoropropane, 1,3-bis(silanodifluoromethylene)disiloxane, bis(1-trifluoromethyldisiloxanyl)difluoromethane, 2,4,6-trisilanetetrafluoropyran, and 2,5-disilanetetrafluorofuran.

4. A process for depositing a low dielectric constant film, comprising reacting a fluorinated carbon derivative of one or more silicon compounds that contain carbon with an oxidizing gas, wherein the oxidizing gas is dissociated prior to mixing with the fluorinated carbon derivative.

5. A process for depositing a low dielectric constant film, comprising:

depositing a conformal lining layer on a patterned metal layer from process gases comprising a fluorinated carbon derivative of one or more silicon compounds that contain carbon and an oxidizing gas; and

depositing a gap filling layer on the lining layer.

6. The process of claim 5, wherein each silicon atom in the fluorinated carbon derivative is bonded to one or two carbon atoms and to at least one hydrogen atom, and wherein silicon atoms in the same molecule are not separated by more than two carbon atoms or by more than one oxygen atom.

7. The process of claim 5, wherein the fluorinated carbon derivative is selected from a group consisting of fluorinated carbon derivatives of methylsilane, dimethylsilane, trimethylsilane, disilanomethane, bis(methyl-silano)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)di-siloxane, bis( 1-methyldisiloxanyl) methane, 2,2-bis(1-methyl -disiloxanyl)propane, 2,4,6,8,10-pentamethylcyclopentasiloxane, 1,3,5,7-tetrasilano-2,-dioxy-4,8-dimethylene, 2,4,6-trisilanetetrahydropyran, 2,5-disilanetetrahydrofuran, and combinations thereof.

8. The process of claim 5, the oxidizing gas is dissociated prior to mixing with the fluorinated carbon derivative.

9. The process of claim 5, wherein the gap filling layer is deposited by reaction of a silano-containing compound and hydrogen peroxide.

10. The process of claim 5, further comprising the step of depositing a capping layer on the gap filling layer from process gases comprising the fluorinated carbon derivatives and the oxidizing gas.

11. The process of claim 5, wherein the fluorinated carbon derivative is selected from a group consisting of trifluoromethylsilane, 1,2-disilanotetrafluoroethane, 1,2-bis(trifluoromethylsilano)tetrafluoroethane, 2,2-disilanohexafluoropropane, 1,3-bis(silanodifluoromethylene)disiloxane, bis(1-trifluoromethyldisiloxanyl)difluoromethane, 2,4,6-trisilanetetrafluoropyran, and 2,5-disilanetetrafluorofuran.