Plasma processes for depositing low dielectric constant films

• US 6,541,282 B1
• Filed: 06/13/2000
• Issued: 04/01/2003
• 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): KUNEMUND, ROBERT M
• Application Number:
  US09/594,187
• Time in Patent Office: 1,022 Days
• Field of Search: 438/710, 438/5, 438/8, 438/9
• US Class Current: 438/5
• 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 428/24926 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 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, or dimethylsilane, (CH₃)₂SiH₂, 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 computer readable medium containing a program which, when executed by a processor performs a step, comprising:

reacting a compound with an oxidizing gas while applying RF power to deposit a low dielectric constant film on a semiconductor substrate, wherein the compound comprises one or more silicon atoms, at least one alkyl group bonded to each silicon atom, and at least one hydrogen atom bonded to each silicon atom, and wherein the low dielectric constant film has a dielectric constant of about 3 or less, is located between conductive materials on said semiconductor substrate, and retains sufficient silicon-carbon bonds to have a carbon content from about 1% to about 50% by atomic weight.

2. The computer readable medium of claim 1, wherein the oxidizing gas and the one or more silicon compounds are reacted at a substrate temperature from about −

20°

C. to about 400°

C.

3. The computer readable medium of claim 1, wherein the RF power is provided by a mixed frequency power source that provides RF power at a high frequency of about 13.56 MHz and a low frequency of about 360 KHz to about 1 MHz.

4. A computer readable medium containing a program which, when executed by a processor performs steps, comprising:

depositing a low dielectric constant film by reacting a compound comprising at least one silicon atom with an oxidizing gas while applying RF power, wherein each silicon atom is bonded to one, two, or three alkyl groups and to at least one hydrogen atom, and wherein the film retains sufficient silicon-carbon bonds to have a carbon content from 1% to 50% by atomic weight and a dielectric constant of about 3 or less;

etching at least one opening in the film; and

depositing a conductive material in the opening.

5. The computer readable medium of claim 4, wherein the film is deposited at a substrate temperature from about −

20°

C. to about 400°

C.

6. A computer readable medium containing a program which, when executed by a processor performs steps, comprising:

depositing a low dielectric constant film by reacting trimethylsilane with an oxidizing gas while applying RF power, wherein the film comprises a carbon content from 1% to 50% by atomic weight and a dielectric constant of about 3 or less;

etching at least one opening in the film; and

depositing a conductive material in the opening.

7. The computer readable medium of claim 6, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.

8. A computer readable medium containing a program which, when executed by a processor performs a step, comprising:

reacting trimethylsilane and an oxidizing gas while applying RF power to deposit a low dielectric constant film on the semiconductor substrate, wherein the low dielectric constant film has a carbon content from 1% to 50% by atomic weight, and has a dielectric constant of about 3 or less.

9. The computer readable medium of claim 8, wherein the RF power is provided by a mixed frequency power source that provides RF power at a high frequency of about 13.56 MHz and a low frequency of about 360 KHz to about 1 MHz.

10. The computer readable medium of claim 8, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.

11. A computer readable medium containing a program which, when executed by a processor performs a step, comprising:

depositing a conformal lining layer on a patterned metal layer from process gases comprising one or more silicon compounds and an oxidizing gas while applying RF power, wherein each silicon atom in each silicon compound is bonded to one, two, or three alkyl groups and to at least one hydrogen atom, and wherein the conformal lining layer retains sufficient silicon-carbon bonds to have a dielectric constant of about 3 or less and a carbon content from 1% to 50% by atomic weight; and

depositing a gap filling layer on the conformal lining layer.

12. The computer readable medium of claim 11, wherein the conformal lining layer is deposited at a substrate temperature from about −

20°

C. to about 400°

C.

15. The computer readable medium of claim 12, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.

13. A computer readable medium containing a program which, when executed by a processor performs a step, comprising:

reacting methylsilane and an oxidizing gas while applying RF power to deposit a dielectric film on a substrate, wherein the dielectric film has a carbon content from 1% to 50% by atomic weight and a dielectric constant less than about 3.

14. The computer readable medium of claim 13, wherein the RF power is provided by a mixed frequency power source that provides RF power at a high frequency of about 13.56 MHz and a low frequency of about 360 KHz to about 1 MHz.

16. A computer readable medium containing a program which, when executed by a processor performs a step, comprising:

reacting an organosilane compound consisting of carbon, silicon, and hydrogen with an oxidizing gas while applying RF power to deposit a dielectric film on a semiconductor substrate, wherein the organosilane compound has three alkyl groups bonded to silicon, and the dielectric film has a carbon content from 1% to 50% by atomic weight and a dielectric constant less than about 3.

17. The computer readable medium of claim 16, wherein the conditions comprise a substrate temperature from about −

20°

C. to about 400°

C.