Method for plasma etching performance enhancement
A method for etching features in a dielectric layer is provided. A mask is formed over the dielectric layer. A protective silicon-containing coating is formed on exposed surfaces of the mask. The features are etched through the mask and protective silicon-containing coating. The features may be partially etched before the protective silicon-containing coating is formed.
1. A method for etching features in a dielectric layer comprising:
forming a mask over the dielectric layer;
forming a protective amorphous or polymorphous silicon-containing coating on exposed surfaces of the mask, wherein the forming the protective silicon-containing coating comprises:
providing a protective coating gas comprising SiF 4 and H 2 ;
transforming the protective coating gas into a plasma;
depositing the protective silicon coating from the plasma; and
stopping the protective coating gas; and
etching the features through the mask and protective silicon-containing coating.
2. The method, as recited in claim 1 , wherein the features have bottoms, wherein the forming a protective silicon-containing coating does not deposit the silicon-containing coating on the bottoms of the features.
3. The method, as recited in claim 1 , wherein the etching the features through the mask and protective silicon-containing coating, comprises:
providing a etching gas that is CH 3 F and CH 2 F 2 free, and
forming a plasma from the etch gas, which etches the features.
4. The method, as recited in claim 3 , further comprising partially etching the features into the dielectric layer to a bowing depth before forming the protective silicon coating.
5. The method, as recited in claim 3 , wherein the forming the protective silicon coating and etching the feature are performed cyclically for at least three cycles.
6. The method, as recited in claim 1 , wherein the depositing the protective coating comprises providing a bias power between 5 and 500 W.
7. The method, as recited in claim 6 , wherein the providing a bias power comprises providing a low frequency RF signal.
8. The method, as recited in claim 7 , wherein the features have vertical profiles.
9. The method, as recited in claim 1 , further comprising partially etching the features into the dielectric layer to a bowing depth before forming the protective silicon coating.
10. The method, as recited in claim 1 , wherein the mask is an organic material mask.
11. A method of etching features in a dielectric layer, comprising:
forming a mask over a dielectric layer;
partially etching features into the dielectric layer;
forming a protective amorphous or polymorphous silicon-containing coating on sidewalls of the partially etched features, wherein the forming the protective silicon-containing coating comprises:
providing a protective coating gas comprising SiF 4 and H 2 ;
transforming the protective coating gas into a plasma;
depositing the protective silicon coating from the plasma; and
stopping the protective coating gas; and
completely etching the features.
12. The method, as recited in claim 11 , wherein the partially etching features etches the features to a bowing depth.
13. The method, as recited in claim 12 , wherein the features have bottoms, wherein the forming a protective silicon-containing coating does not deposit the silicon-containing coating on the bottoms of the features.
14. The method, as recited in claim 13 , wherein the depositing the protective coating comprises providing a bias power between 5 and 500 W.
15. The method, as recited in claim 14 , wherein the providing a bias power comprises providing a low frequency RF signal.
16. The method, as recited in claim 15 , wherein the features have vertical profiles.
17. The method, as recited in claim 11 , wherein the mask is an organic material mask.
18. The method, as recited in claim 11 , wherein the completely etching the features, comprises:
providing a etch gas, which is CH 3 F and CH 2 F 2 free; and
forming a plasma from the etch gas, which etches the features.