Semiconductor device having a sac through-hole

Abstract

A process for manufacturing a semiconductor device includes the steps of: forming a gate oxide film and a gate electrode on a substrate; forming a SiCN protection film on the gate electrode; depositing an interlayer dielectric film for covering the SiCN protection film; etching the dielectric film in a self-alignment with the SiCN protection film to form a contact hole; and forming a contact plug connected to the surface of the substrate in the contact hole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing the configuration of a semiconductor device according to an embodiment of the present invention;

FIGS. 2A to 2J are sectional views consecutively showing the fabrication steps of a process for manufacturing the semiconductor device of FIG. 1;

FIG. 3 is a sectional view showing the configuration of a CVD system for use in the process for forming the SiCN film;

FIG. 4 is a graph showing the content ratios in the semiconductor devices of first through third examples of the present invention and a comparative example;

FIG. 5 is a graph showing the relationship between the dielectric constant as well as the etch selectivity and the substrate temperature in the step for forming the SiCN film;

FIG. 6 is a sectional view showing the configuration of a semiconductor device according to a modification of the present embodiment; and

FIGS. 7A and 7B are sectional views showing manufacturing steps of the semiconductor device shown in FIG. 6.

Claims

1. A semiconductor device comprising the steps of: a first insulating film exposing therefrom a conductive material overlying a substrate;an interconnect line formed on said first insulating film;a SiCN protection film covering a surface of said interconnect line;a second insulating film formed on said first insulating film and covering said SiCN protection film; anda via-plug penetrating said second insulating film and formed in self-alignment with said protection film, to connect to said conductive material.

2. The semiconductor device according to claim 1, wherein said SiCN film has a dielectric constant of 5.9 or less.

3. The semiconductor device according to claim 1, wherein said conductive material is connected to another interconnect line.

4. The semiconductor device according to claim 1, wherein said conductive material is connected to a semiconductor substrate.

5. A method for manufacturing a semiconductor device comprising the steps: forming a first insulating film overlying a substrate and exposing therefrom a conductive material;forming a second interconnect line on said second insulating film;forming a SiCN protection film covering a surface of said second interconnect line;forming a second insulating film on said first insulating film and covering said SiCN protection film;etching said second insulating film in self-alignment with said SiCN protection film to form a through-hole;forming a via-plug within said through-hole, said via-plug connecting to said conductive material.

6. The method according to claim 5, said SiCN protection film forming step includes the step of depositing SiCN at a substrate temperature between 500 degrees C. and 550 degrees C.

7. The method according to claim 5, wherein said SiCN film has a dielectric constant of 5.9 or less.

8. The method according to claim 5, further comprising the step of forming a sidewall protection film covering an internal sidewall of said through-hole.

9. The method according to claim 5, wherein said conductive material is connected to another interconnect line.

10. The method according to claim 5, wherein said conductive material is connected to said semiconductor substrate.