Claims
- 1. A method for forming a damascene interconnect structure with a bi-layer capping film, comprising the following steps:
providing a semiconductor wafer; depositing a dielectric layer over the semiconductor wafer, the dielectric layer having a main surface and a damascened recess on the main surface; depositing a copper layer in the damascened recess and to fill the damascened recess; performing a chemical mechanical polishing process to polish the copper layer such that the copper layer has an exposed upper surface substantially co-planar with the main surface of the dielectric layer; and capping the exposed upper surface with a bi-layer capping film consisting of a lower HDPCVD silicon nitride layer and an upper doped silicon carbide layer.
- 2. The method according to claim 1 wherein after polishing the copper layer to form the upper surface and before capping the exposed upper surface with the bi-layer capping film, the upper surface is pre-treated by hydrogen or ammonia plasma for reducing residual copper oxides on the upper surface.
- 3. The method according to claim 2 wherein the hydrogen or ammonia plasma pre-treatment is carried out at a temperature of below 300° C. for a time period of about 10 seconds to 60 seconds.
- 4. The method according to claim 1 wherein the lower HDPCVD silicon nitride layer is formed by high density plasma chemical vapor deposition (HDPCVD) at a temperature of below 350° C.
- 5. The method according to claim 1 wherein the upper doped silicon carbide layer is composed of oxygen doped silicon carbide (SiCOH) or nitrogen doped silicon carbide (SiCNH).
- 6. The method according to claim 5 wherein the upper doped silicon carbide layer is produced by a chemical vapor deposition (CVD) process, in which 3-methyl silane or 4-methyl silane is used as a precursor.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a division application of U.S. patent application Ser. No. 10/248,750 entitled “DAMASCENE INTERCONNECT WITH BILAYER CAPPING FILM”, filed Feb. 14, 2003 by Jei-Ming Chen, Yi-Fang Chiang, and Chih-Chien Liu.
Divisions (1)
|
Number |
Date |
Country |
Parent |
10248750 |
Feb 2003 |
US |
Child |
10708426 |
Mar 2004 |
US |