Surface treatment of C-doped SiO2 film to enhance film stability during O2 ashing

• US 6,465,372 B1
• Filed: 08/07/2000
• Issued: 10/15/2002
• Est. Priority Date: 08/17/1999
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Xia, Li-Qun, Gaillard, Frederic, Yieh, Ellie, Lim, Tian-Hoe
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): Le, Thao P
• Application Number:
  US09/633,495
• Time in Patent Office: 799 Days
• Field of Search: 438/787, 438/758, 438/789, 438/790, 438/784
• US Class Current: 438/787
• CPC Class Codes: C23C 16/0218 in a reactive atmosphere C23C16/0227 takes precedence
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/56 After-treatment
• 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 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02312 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC

Abstract

A method for forming an insulation layer over a substrate. The method forms a carbon-doped silicon oxide layer by thermal chemical vapor deposition using an organosilane. The carbon-doped silicon oxide layer is subsequently cured and densified. In one embodiment, the cured film is densified in a nitrogen-containing plasma. The method is particularly suitable for deposition of low dielectric constant films, i.e., where k is less than or equal to 3.0. Low-k, carbon-doped silicon oxide methylsilane or di-, tri-, tetra-, or phenylmethylsilane. and ozone. The above method can be carried out in a substrate processing system having a process chamber; a substrate holder, a heater, a gas delivery system, and a power supply, all of which are coupled to a controller. The controller contains a memory having a computer-readable medium with a program embodied for directing operation of the system in accordance with above method.

Claims

1. A method for treating a carbon-doped silicon oxide layer over a substrate disposed in a substrate processing chamber, the method comprising:

flowing a process gas comprising ozone and an organosilane into the substrate processing chamber;

heating the substrate to a temperature of less than about 250°

C. to form a carbon-doped silicon oxide layer over the substrate;

curing the carbon-doped silicon oxide layer after it is formed over the substrate; and

densifying the carbon-doped silicon oxide layer after said curing by subjecting the carbon-doped silicon oxide layer to a plasma.

2. The method of claim 1 wherein said plasma contains helium (He), nitrogen (N₂), or Argon (Ar).

3. The method of claim 2 wherein said plasma is an N₂ plasma.

4. The method of claim 3 wherein the substrate is exposed to said N₂ plasma for between 1 and 10 minutes.

5. The method of claim 4 wherein said N₂ plasma is sustained by radio frequency (RF) energy.

6. The method of claim 5 wherein said RF energy is delivered at a power of between 500 and 900 watts.

7. The method of claim 5 wherein said RF energy is delivered at a frequency of between 100 kilohertz and 100 megahertz.

8. The method of claim 5 wherein said N₂ plasma has a pressure of between about 1.2 and 4 torr.

9. The method of claim 1 wherein the organosilane precursor is selected from the group of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane and phenylmethylsilane.

10. The method of claim 1 wherein the dielectric constant of said carbon-doped silicon oxide layer is less than or equal to 3.0.

11. The method of claim 1 wherein densifying includes heating the substrate.

12. The method of claim 11 wherein the substrated to a temperature of between approximately 350°

C. and 450°

C. during the densifying.

13. The method of claim 1 wherein said plasma is generated in the processing chamber.

14. The method of claim 1 wherein said plasma is generated remote from the processing chamber and then flowed to the processing chamber.

15. The method of claim 1 wherein the carbon-doped silicon oxide layer is formed over the substrate as a result of a thermal process.