Process for masking and removal of residue from complex shapes
View Patent ↗A process is provided for etching a mask layer and removal of residue from a structure having an area sheltered from directional etching. The structure has a shape that forms a silhouette area obstructed from being etched by anisotropic bombardment originating from a first direction, and a mask formed over the mask layer over the structure; A first etch process removes at least a part of the mask layer and retains at least a part of mask layer in the sheltered area. A second etch process removes at least a part of the mask layer in the sheltered area by hydrogen based microwave plasma etching.
1. A process for etching a mask layer and removal of residue from a structure having an area sheltered from directional etching, comprising:
providing the structure comprising a shape;
the shape forming a silhouette area obstructed from being etched by anisotropic bombardment originating from a first direction;
forming the mask layer over the structure;
performing a first etch process to remove at least a part of the mask layer and retain at least a part of mask layer in the sheltered area, and
performing a second etch process to remove at least a part of the mask layer in the sheltered area by hydrogen based microwave plasma etching.
2. The process of claim 1 wherein the structure comprises a cantilever, the cantilever comprising a top and a support; wherein the top overhangs the support.
3. The process of claim 1 wherein the structure comprises
a substrate with a top surface;
a trench in the top surface, the trench further comprising a side wall and a bottom, wherein
the top surface overhangs at least one of the side wall and the bottom.
4. The process of claim 1 wherein the structure comprises a trapezoid with a top and a bottom, wherein the top is wider than the bottom.
5. The process of claim 1 wherein the first etch process comprises a wet etch.
6. The process of claim 5 wherein the wet etch process comprises a photoresist developer.
7. The process of claim 1 wherein the first etch process comprises an anisotropic dry etch.
8. The process of claim 7 wherein the anisotropic dry etch comprises inductively coupled plasma etching.
9. The process of claim 1 wherein the mask layer further comprises:
a antireflective layer deposited on the structure, and
photoresist deposited on the antireflective layer.
10. The process of claim 1 , wherein the mask layer comprises at least one of the following:
an organic photoresist;
a hydrocarbon, and
a Developable Bottom Anti-Reflection Coating (DBARC).
11. The process of claim 1 wherein the hydrogen based plasma comprises CH 3 OH.
12. The process of claim 11 further comprising:
CH 3 OH ion density greater than 0.5×10 12 per cm 3 , and a gas pressure between 75 mTorr and 750 mTorr.
13. The process of claim 12 further comprising a gas flow rate between 80 ml/minute and 200 ml/minute.
14. The process of claim 12 further comprising a plasma temperature between 80° C. and 150° C.
15. The process of claim 12 further comprising a microwave power between 100 and 1000 watts.
16. The process of claim 1 wherein the hydrogen based microwave plasma comprises a mixture of nitrogen and hydrogen.
17. The process of claim 16 further comprising:
N 2 /H 2 ion density greater than 0.5×10 12 per cm 3 , and a gas pressure between 75 mTorr and 750 mTorr.
18. The process of claim 17 further comprising a gas flow rate between 80 ml/minute and 200 ml/minute.
19. The process of claim 17 further comprising a plasma temperature between 80° C. and 150° C.
20. The process of claim 17 further comprising a microwave power between 100 and 1000 watts.