Method for fabricating metal pattern in semiconductor device
View Patent ↗A method for fabricating a metal pattern in a semiconductor device includes forming a metal layer over a substrate, forming a hard mask layer over the metal layer, forming a sacrifice pattern over the hard mask layer, forming a spacer pattern on sidewalks of the sacrifice pattern, removing the sacrifice pattern, forming a hard mask pattern by etching the hard mask layer using the spacer pattern as an etch barrier, forming an etching protection layer over the hard mask pattern and on sidewalks of the hard mask pattern, and forming the metal pattern by performing primary and secondary etching processes on the metal layer using the etching protection layer as an etch barrier.
1. A method for fabricating a metal pattern in a semiconductor device, comprising:
forming a metal layer over a substrate;
forming a hard mask layer over the metal layer;
forming a sacrifice pattern over the hard mask layer;
forming a spacer pattern on sidewalls of the sacrifice pattern;
then completely removing the sacrifice pattern;
forming a hard mask pattern by etching the hard mask layer using the spacer pattern as an etch barrier;
forming an etching protection layer along a surface of the substrate including the hard mask pattern;
removing the etching protection layer formed on the metal layer to form etching protection patterns; and
forming the metal pattern by performing primary and secondary etching processes on the metal layer using the etching protection patterns as an etch barrier.
2. The method of claim 1 , wherein the hard mask layer comprises a stacked structure of a hard mask nitride layer, a carbon layer, a silicon oxynitride layer, and a polysilicon layer.
3. The method of claim 1 , wherein the sacrifice pattern comprises a carbon layer.
4. The method of claim 1 , wherein the sacrifice pattern comprises a spin on carbon (SOC) layer or an amorphous carbon layer.
5. The method of claim 1 , wherein the removing of the sacrifice pattern is performed by an oxygen stripping process.
6. The method of claim 1 , wherein the spacer pattern is formed of a material having an etching selectivity with respect to the sacrifice pattern and the hard mask layer.
7. The method of claim 6 , wherein the spacer pattern is formed of oxide.
8. The method of claim 1 , wherein the spacer pattern comprises an ultra low temperature oxide (ULTO).
9. The method of claim 1 , wherein the etching protection layer comprises an ultra low temperature oxide (ULTO).
10. The method of claim 9 , wherein the ULTO is formed at a temperature of 75° C. to 100° C.
11. The method of claim 1 , wherein the etching protection layer is formed to have a thickness of 30 Å to 50 Å.
12. The method of claim 1 , wherein the primary etching process is performed using a gas mixture of NF 3 and Cl 2 .
13. The method of claim 1 , wherein the secondary etching process is performed to etch the metal layer and simultaneously remove the etching protection layer.
14. The method of claim 1 , wherein the secondary etching process is performed using a gas mixture of CF 4 and Cl 2 .
15. The method of claim 1 , wherein the primary etching process includes etching the exposed metal layer between the etching protection patterns.
16. The method of claim 15 , wherein the secondary etching process includes etching the exposed metal layer over the substrate.
17. The method of claim 15 , wherein the secondary etching process further comprises:
removing the etching protection layer formed on the sidewalls of the hard mask pattern.