Method for etching a metal layer in a semiconductor device
View Patent ↗A method for etching a metal layer on which an oxide-based ARC layer is coated in a semiconductor device comprises the step of performing a dry cleaning process by using a Cl 2 /CHF 3 based gas, after dry cleaning the ARC layer by using the oxide-based gas. As a result, the etching rates of the center area and the edge area are substantially same.
1. A method for etching a metal layer having an oxide-based antireflective coating (ARC) layer thereon comprising the steps of:
performing a first dry cleaning process in an etching chamber with an oxide-based gas;
performing a second dry cleaning process in the chamber with a gas mixture comprising Cl 2 and CHF 3 ; then etching the metal layer.
2. The method of claim 1 , wherein a flow rate of the Cl 2 ranges from about 100 seem to about 200 seem.
3. The method of claim 1 , wherein a flow rate of the CHF 3 ranges from about 5 seem to about 30 seem.
4. The method of claim 1 , wherein a pressure of the dry cleaning processes ranges from about 8 mTorr to about 50 mTorr.
5. The method of claim 1 , wherein a source power of the dry cleaning processes ranges from about 500 W to about 1200 W.
6. The method of claim 1 , wherein a bias power of the dry cleaning processes ranges from about 0 W to about 10 W.
7. The method of claim 1 , wherein the dry cleaning processes arc performed for about 5 seconds to about 30 seconds.
8. The method of claim 1 , wherein the oxide-based gas comprises oxygen.
9. The method of claim 1 , wherein the dry cleaning processes are performed sequentially in a single etching chamber.
10. The method of claim 1 , wherein the metal layer and ARC layer are on a wafer having a center area and an edge area, and the dry cleaning processes decrease a microloading effect in the edge area.
11. The method of claim 10 , wherein the metal layer is etched at a rate that is substantially the same in the center area and the edge area.
12. The method of claim 1 , wherein the second dry cleaning process eliminates polymers deposited in the chamber.
13. The method of claim 1 , wherein the second dry cleaning process eliminates aluminum- and silicon-containing byproducts.
14. The method of claim 1 , wherein the metal layer comprises an aluminum layer.
15. The method of claim 14 , wherein the metal layer further comprises a titanium nitride layer under the aluminum layer.
16. The method of claim 1 , wherein the ARC layer comprises a silicon oxide.