Semiconductor device fabrication method
A method of performing microfabrication using a hard mask in the manufacture of a semiconductor device having an interlayer dielectric (ILD) film made of low-dielectric constant, K, insulating material is provided. When treating a low-K dielectric film for use in semiconductor integrated circuitry and its underlying etching stopper film, a patterned resist film is used as a mask to etch a hard mask film. Subsequently, the resist pattern is subjected to stripping or “ashing” in the atmosphere of a mixture gas of hydrogen (H 2 ) and helium (He) at a temperature higher than 200° C. under a pressure of about 1 Torr. With this procedure, microfabrication relying upon the hard mask less in facet is achievable during its subsequent etching of the low-K dielectric film, without damaging the hard mask film upon removal of the resist.
1. A method of making a semiconductor device comprising:
forming on or above a substrate an insulative film with a low dielectric constant, wherein said low dielectric constant insulative film is any one of a low dielectric constant insulator film containing Si, C, O and H or an organic hydrocarbon polymer-based low dielectric constant insulator film, each said insulator film having a dielectric constant of less than or equal to three;
forming a hard mask film on the low dielectric constant insulative film;
forming on a surface of said hard mask film a resist pattern through deposition and development of a resist film;
etching said hard mask film with said resist pattern as a mask to thereby form a hard mask;
removing said resist pattern by an ashing treatment; and
etching said low dielectric constant insulative film by use of said hard mask to thereby form a pattern, wherein
during the ashing of said resist pattern, the resist is stripped away by using a mixture gas of hydrogen (H2) and helium (He).
2. The method according to claim 1 , wherein said hard mask film is made of a material as selected from the group consisting of SiC, SiOC, SiN and SiCN.
3. The method according to claim 1 , wherein said low dielectric constant insulative film is made of at least one material as selected from the group consisting of MSQ, MHSQ, SiOC, PAE, BCB and polyimide.
4. The method according to claim 1 , wherein said low dielectric constant insulative film is formed by any one of chemical vapor deposition (CVD) and coating techniques.
5. The method according to claim 1 , wherein said low dielectric constant insulative film is a layer of porous material.
6. A method of making a semiconductor device comprising:
forming on or above a substrate an insulative film with a low dielectric constant;
forming a hard mask film on the low dielectric constant insulative film;
forming on a surface of said hard mask film a resist pattern through deposition and development of a resist film;
etching said hard mask film with said resist pattern as a mask to thereby form a hard mask;
removing said resist pattern by an ashing treatment; and
etching said low dielectric constant insulative film by use of said hard mask to thereby form a pattern, wherein
during the ashing of said resist pattern, the resist is stripped away by using a mixture gas of hydrogen (H2) and helium (He),
wherein any one of said hard mask film and said low dielectric constant insulative film is etched by using a reactive ion etcher with radio frequency (RF) biased parallel flat plates.
7. The method according to claim 1 , wherein during the ashing of said resist pattern, an ashing temperature is set to range from 200 to 400° C.
8. The method according to claim 1 , wherein during the ashing of said resist pattern, ashing is done by use of a remote plasma processing device.
9. The method according to claim 1 , wherein during the ashing of said resist pattern, a pressure is 50 to 1×10 5 Pa.
10. The method according to claim 1 , wherein said substrate is a substrate having a wiring layer made of copper.
11. The method according to claim 1 further comprising:
forming an etch stop film between said substrate and said low dielectric constant insulative film.
12. The method according to claim 10 , wherein said etch stop film is made of a material as selected from the group consisting of SiC, Si 3 N 4 , SiCN and SiCO.
13. The method according to claim 1 , wherein the mixture gas of H2 and He as used during the ashing of said resist pattern has a hydrogen concentration ranging from 1 to 20 volume percent.