Methods for producing low-k CDO films

• US 7,341,761 B1
• Filed: 03/11/2004
• Issued: 03/11/2008
• Est. Priority Date: 03/11/2004
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Wu, Qingguo, Fu, Haiying, Tang, Xingyuan
• Primary Examiner(s): CHEN, BRET P
• Application Number:
  US10/800,409
• Time in Patent Office: 1,461 Days
• Field of Search: 427/255.37, 427/249.1, 427/579, 427/99, 438/787, 438/788, 438/789, 438/790
• US Class Current: 427/255.37
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/505 using radio frequency discharges
• CPC Class Codes: C23C 16/517 using a combination of discharges covered by two or more of groups C23C16/503 - C23C16/515

Abstract

Methods of preparing a carbon doped oxide (CDO) layers having a low dielectric constant are provided. The methods involve, for instance, providing a substrate to a deposition chamber and exposing it to one or multiple carbon-doped oxide precursors having molecules with at least one carbon—carbon triple bond, or carbon—carbon double bond, or a combination of these groups and depositing the carbon doped oxide dielectric layer under conditions in which the resulting dielectric layer has a dielectric constant of not greater than about 2.7.

Claims

1. A method of preparing a carbon doped silicon oxide (CDO) film on a substrate, the method comprising:

(a) providing the substrate to a deposition chamber; and

(b) contacting the substrate with a primary CDO precursor and a secondary CDO precursor, wherein the primary CDO precursor is an alkylsiloxane and wherein the secondary precursor contains a carbon—

carbon triple bond, under process conditions whereby the CDO film is formed on the substrate, and whereby the CDO film contains carbon—

carbon triple bonds and the CDO film has a dielectric constant of less than 2.7,

wherein the secondary CDO precursor comprises one or more compounds selected from the list consisting of Ethynyltrimethylsilane (ETMS), Propargyltrimethylsilane (PTMS), Propargyloxytrimethylsilane (POTMS), Bis(trimethylsilyl)acetylene (BTMSA), 1,3-Diethynyltetramethyldisiloxane (DTDS), Dimethylmethoxysilaneacetylene (DMMOSA), Methyldimethoxysilaneacetylene (MDMOSA), Dimethylethoxysilaneacetylene (DMEOSA), Methyldiethoxysilaneacetylene (MDEOSA), Ethyldiethoxysilaneacetylene (EDEOSA), and Dimethylsilane-diacetylene (DMSDA).

2. The method of claim 1, wherein the CDO film has a dielectric constant of not greater than about 2.6.

3. The method of claim 1, wherein the substrate is a partially fabricated integrated circuit.

4. The method of claim 3, wherein the CDO film is an interlayer dielectric in an integrated circuit.

5. The method of claim 1, wherein the deposition chamber comprises one or multiple stations that allow processing one or multiple substrates in parallel.

6. The method of claim 1, wherein the CDO film is formed on the substrate by a chemical vapor deposition process.

7. The method of claim 1, wherein the CDO film is formed on the substrate by a plasma enhanced chemical vapor deposition (PECVD) process.

8. The method of claim 1, wherein the primary CDO precursor comprises an alkylcyclotetrasiloxane.

9. The method of claim 1, wherein the CDO precursors are provided in a carrier gas.

10. The method of claim 9, wherein the carrier gas comprises one or more gases selected from the group consisting of carbon dioxide, oxygen, ozone, nitrous oxide and hydrogen peroxide.

11. The method of claim 9, wherein the carrier gas comprises one or more gases selected from the group consisting of helium, argon, and other inert gases.

12. The method of claim 1, wherein the as deposited CDO film has a carbon—

carbon triple bond to silicon-oxygen bond ratio of about 0.05% to 20% based on FTIR peak areas.

13. The method of claim 12, where the as deposited CDO film also contains derivative bond structures of carbon—

carbon triple bonds, wherein the derivative bond structures include one or more of the following;

carbon—

carbon double bonds, carbon—

carbon single bonds, and their crosslinked forms within the Si—

O—

Si matrix.

14. The method of claim 1, wherein the CDO film has a carbon-carbon triple bond to silicon oxide bond ratio of about 0.3% to 7% based on FTIR peak area.