Purge heater design and process development for the improvement of low k film properties

• US 6,709,721 B2
• Filed: 03/28/2001
• Issued: 03/23/2004
• Est. Priority Date: 03/28/2001
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Venkataraman, Shankar, Rocha-Alvarez, Juan Carlos, Chen, Chen-An, Yieh, Ellie
• Primary Examiner(s): MEEKS, TIMOTHY HOWARD
• Application Number:
  US09/820,586
• Publication Number:
  US 20020187262A1
• Time in Patent Office: 1,091 Days
• Field of Search: 427/569, 427/249.1, 427/249.15, 427/579, 427/578, 427/255.37, 438/778, 438/780, 438/786, 438/787
• US Class Current: 427/569
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/455 characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
• CPC Class Codes: C23C 16/45521 the gas, other than thermal contact gas, being introduced the rear of the substrate to flow around its periphery
• CPC Class Codes: C23C 16/4585 Devices at or outside the perimeter of the substrate support, e.g. clamping rings, shrouds
• 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 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: Y10T 428/31 Surface property or characteristic of web, sheet or block

Abstract

The present invention provides a method of depositing a carbon doped silicon oxide film having a low dielectric constant (k). A process gas mixture containing at least a carrier gas, an oxidizer, a carbon gas source, or combinations thereof, is supplied adjacent an edge of a substrate though a purge gas inlet in a substrate support to facilitate deposition of low k carbon doped silicon oxide film having a greater concentration of silicon oxide around the edge of the substrate than an inner portion of the substrate.

Claims

1. A method for depositing a film on a substrate, comprising:

positioning a substrate in a chamber on a substrate support;

flowing a carrier gas into the chamber;

flowing a process gas mixture adjacent an edge of the substrate through a purge gas inlet in the substrate support;

generating a plasma;

delivering a first carbon silicon gas source to the chamber through another gas inlet; and

depositing on the substrate a film that has a different composition at the edge of the substrate than at the center of the substrate.

2. The method of claim 1, wherein the process gas mixture delivered to the edge of the substrate comprises an oxidizer and a carrier gas.

3. The method of claim 2, wherein the process gas mixture is delivered to the edge of the substrate through the purge gas inlet at a flow rate of about 1 sccm to about 150 sccm.

4. The method of claim 3, wherein the process gas mixture delivered to the edge of the substrate further comprises a second carbon silicon gas source.

5. The method of claim 4, wherein the first and second carbon silicon gas sources are selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, 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-tetramethylcyclotetrasiloxane (TMCTS), 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, fluorinated carbon derivatives thereof, and combinations thereof.

6. The method of claim 5, wherein the carrier gas in the process mixture delivered to the edge of the substrate is selected from the group consisting of argon, helium, and combinations thereof.

7. The method of claim 6, wherein the oxidizer delivered to the edge of the substrate is selected from the group consisting of oxygen (O₂), carbon monoxide (CO), carbon dioxide (CO₂), water (H₂O), nitrous oxide (N₂O), and ozone (O₃).

8. The method of claim 7, wherein the first carbon silicon gas source is delivered to the chamber at a flow rate of about 500 sccm to about 1700 sccm.

9. The method of claim 7, wherein the substrate is maintained at a temperature of about 300°

C. to about 400°

C.

10. The method of claim 9, wherein a chamber pressure is maintained from about 2 Torr to about 6 Torr.

11. The method of claim 10, further comprising:

supplying an RF power source to the chamber at a power level from about 100 W to about 1500 W.

12. The method of claim 11, further comprising:

flowing a second oxidizer into the chamber at a flow rate of about 150 sccm to about 800 sccm.

13. The method of claim 3, wherein the process gas mixture delivered to the edge of the substrate further comprises tetraethyl orthosilicate (TEOS).

14. The method of claim 1, wherein the process gas mixture delivered to the edge of the substrate comprises a self-oxidizing carbon silicon gas source.

15. The method of claim 14, wherein the first carbon silicon gas source delivered to the chamber is self-oxidizing.

16. The method of claim 1, wherein the film has a higher concentration of oxygen at the edge of the substrate than at the center of the substrate.

17. A method for depositing a film on a substrate, comprising:

positioning a substrate in a chamber on a substrate support;

flowing a carrier gas into the chamber;

flowing a process gas mixture comprising an oxygen source adjacent an edge of the substrate through a purge gas inlet in the substrate support;

generating a plasma;

delivering a first carbon silicon gas source to the chamber through another gas inlet; and

depositing on the substrate a film that has a higher concentration of silicon oxide at the edge of the substrate than at the center of the substrate.

18. The method of claim 17, wherein the oxygen source is selected from the group consisting of oxygen, ozone, and tetraethyl orthosilicate.

19. The method of claim 17, further comprising delivering an oxidizer to the chamber through a gas inlet other than the purge gas inlet.

20. The method of claim 17, wherein the process gas mixture delivered to the edge of the substrate further comprises a second carbon silicon gas source.

21. A method for depositing a film on a substrate, comprising:

positioning a substrate in a chamber on a substrate support;

flowing a carrier gas into the chamber;

flowing a process gas mixture comprising an oxygen source adjacent an edge of the substrate through a purge gas inlet in the substrate support;

generating a plasma;

delivering a first carbon silicon gas source consisting of carbon, silicon, and hydrogen to the chamber through another gas inlet; and

depositing a film comprising oxygen on the substrate, wherein the film has a different composition at the edge of the substrate than at the center of the substrate.

22. The method of claim 21, wherein the first carbon silicon gas source is selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, disilanomethane, bis(methyl-silano)methane, 1,2-disilanoethane, 1,2-bis(methylsilano)ethane, 2,2-disilanopropane, 1,3,5-trisilano-2,4,6-trimethylene, ethylsilane, phenylsilane, diphenylsilane, methylphenylsilane, and combinations thereof.