Enhancement in UV curing efficiency using oxygen-doped purge for ultra low-K dielectric film

• US 8,753,449 B2
• Filed: 05/29/2013
• Issued: 06/17/2014
• Est. Priority Date: 06/25/2012
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Hendrickson, Scott A., Baluja, Sanjeev, Rocha-Alvarez, Juan Carlos, Demos, Alexandros T., Chhabra, Mahendra, Kiyohara, Tsutomu
• Primary Examiner(s): GREEN, TELLY D
• Application Number:
  US13/904,468
• Publication Number:
  US 20130344704A1
• Time in Patent Office: 384 Days
• Field of Search: 134/1.1, 134/31, 134/1, 134/1.2, 134/1.3, 134/21, 134/902, 118/723.R
• US Class Current: 134/1.1
• CPC Class Codes: B05D 3/066 involving also the use of a gas
• CPC Class Codes: C23C 14/00 Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
• CPC Class Codes: C23C 16/4405 Cleaning of reactor or parts inside the reactor by using reactive gases
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: G02B 1/00 Optical elements characterised by the material of which they are made; Optical coatings for optical elements
• 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 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826

Abstract

Embodiments of the invention provide methods for curing an ultra low-k dielectric film within a UV processing chamber. In one embodiment, the method includes depositing an ultra low-k dielectric layer on a substrate in a deposition chamber, and subjecting the deposited ultra low-k dielectric layer to a UV curing processes in a UV processing chamber. The method includes stabilizing the UV processing chamber by flowing an oxygen gas and a purge gas into the UV processing chamber at a flow ratio of about 1:50000 to about 1:100. While flowing the oxygen-doped purge gas, the substrate is exposed to UV radiation to cure the deposited ultra low-k dielectric layer. The inventive oxygen-doped purge curing process provides an alternate pathway to build silicon-oxygen network of the ultra low-k dielectric material, thereby accelerating cross-linking efficiency without significantly affecting the film properties of the deposited ultra low-k dielectric material.

Claims

1. A method for processing a substrate, comprising:

depositing an ultra low-k dielectric layer having a dielecric constant of less than about 2.5 on a substrate supported by a substrate support in a deposition chamber; and

subjecting the deposited ultra low-k dielectric layer to a ultraviolet (UV) curing process in a UV processing chamber, comprising;

stabilizing the UV processing chamber by flowing a purge gas and an oxygen gas into the UV processing chamber at a flow ratio of about 1 (oxygen gas);

6400 (purge gas) to about 1 (oxygen gas);

300 (purge gas), wherein the oxygen gas is flowed into the UV processing chamber at a flow rate of about 1.0 sccm to about 30 sccm for a 300 mm diameter substrate;

exposing the deposited ultra low-k dielectric layer to UV radiation;

terminating flow of the oxygen gas while still flowing purge gas into the UV processing chamber with UV radiation turned off or remains on; and

pumping residues and unwanted produces out of the UV processing chamber.

2. The method of claim 1, wherein the ultra low-k dielectric layer comprises carbon-doped silicon oxides.

3. The method of claim 1, wherein the purge gas comprises helium gas, argon gas, nitrogen gas, or a combination thereof.

4. The method of claim 1, wherein the deposited ultra low-k dielectric layer is exposed to UV radiation at a UV intensity of about 100 mW/cm² to about 2000 mW/cm² for about 2 seconds to about 20 minutes.

5. The method of claim 1, further comprising:

rotating a UV source at different circumferential positions between 90 degrees and 270 degrees or between 0 degree and 180 degrees.

6. The method of claim 1, further comprising:

flowing the oxygen gas and the purge gas for only a short period of time during the UV curing process while continuously rotating the substrate support.

14. The method of claim 1, wherein the oxygen is flowed into the UV processing chamber at a flow rate of about 1 sccm to about 30 sccm.

7. A method for processing a substrate, comprising:

depositing an ultra low-k dielectric layer having a dielecric constant of less than about 2.5 on a substrate in a deposition chamber;

transferring the substrate to an ultraviolet (UV) processing chamber;

flowing an oxygen gas and a purge gas comprising helium gas and argon gas into the UV processing chamber at a flow ratio of about 1 (oxygen gas);

6400 (purge gas) to about 1 (oxygen gas);

300 (purge gas), wherein the oxygen gas is flowed into the UV processing chamber at a flow rate of about 1.0 sccm to about 30 sccm for a 300 mm diameter substrate;

exposing the deposited ultra low-k dielectric layer to UV radiation;

turning off UV radiation or remains on;

terminating flow of the oxygen gas while still flowing helium gas and argon gas into the UV processing chamber; and

pumping residues and unwanted produces out of the UV processing chamber.

8. The method of claim 7, wherein the ultra low-k dielectric layer comprises carbon-doped silicon oxides.

9. The method of claim 7, further comprising rotating a UV source at different circumferential positions between 0 degree and 270 degrees, or continuously rotating the substrate support during the process.

10. The method of claim 7, further comprising:

transferring the substrate out of the UV processing chamber;

introducing an oxygen-containing gas into an upper processing region of the UV processing chamber, the upper processing region located between a transparent window and a transparent showerhead positioned within the UV processing chamber;

flowing the oxygen-containing gas through one or more passages formed in the transparent showerhead and into a lower processing region, the lower processing region located between the transparent showerhead and a substrate support located within the UV processing chamber;

exposing the oxygen-containing gas to UV radiation to generate reactive oxygen radicals; and

removing unwanted residues or deposition build-up from exposed surfaces of chamber components presented in the UV processing chamber using the reactive oxygen radicals.

11. The method of claim 10, wherein the introducing oxygen-containing gas into the upper processing region further comprises:

flowing the oxygen-containing gas radially from a gas distribution ring configured to surround a circumference of the transparent window to one or more passages formed in the transparent showerhead.

12. The method of claim 11, further comprising:

ejecting the oxygen-containing gas radially from the lower processing region into a gas outlet ring configured to surround a circumference of the transparent showerhead.

13. The method of claim 10, wherein the oxygen-containing gas comprises ozone (O₃) gas, oxygen (O₂) gas, nitrous oxide (N₂O), nitrogen monoxide (NO), carbon monoxide (CO), carbon dioxide (CO₂), or a combination thereof.

15. The method of claim 7, wherein the oxygen is flowed into the UV processing chamber at a flow rate of about 1 sccm to about 30 sccm.

16. A method for processing a substrate, comprising:

subjecting an ultra low-k dielectric layer having a dielecric constant of less than about 2.5 to a ultraviolet (UV) curing process in a UV processing chamber, comprising;

flowing a purge gas and an oxygen gas into the UV processing chamber at a flow ratio of about 1 (oxygen gas);

6400 (purge gas) to about 1 (oxygen gas);

300 (purge gas), wherein the oxygen gas is flowed into the UV processing chamber at a flow rate of about 1.0 sccm to about 30 sccm for a 300 mm diameter substrate; and

exposing the ultra low-k dielectric layer to UV radiation.

17. The method of claim 16, wherein the oxygen is flowed into the UV processing chamber at a flow rate of about 5 sccm to about 12 sccm.