ARC residue-free etching
View Patent ↗Antireflective residues during pattern transfer and consequential short circuiting are eliminated by employing an underlying sacrificial layer to ensure complete removal of the antireflective layer. Embodiments include forming a hard mask layer over a conductive layer, e.g., a silicon substrate, forming the sacrificial layer over the hard mask layer, forming an optical dispersive layer over the sacrificial layer, forming a silicon anti-reflective coating layer over the optical dispersive layer, forming a photoresist layer over the silicon anti-reflective coating layer, where the photoresist layer defines a pattern, etching to transfer the pattern to the hard mask layer, and stripping at least the optical dispersive layer and the sacrificial layer.
1. A method comprising:
forming a hard mask layer over a silicon substrate;
forming a sacrificial layer over the hard mask layer;
forming an optical dispersive layer over the sacrificial layer;
forming a silicon anti-reflective coating layer over the optical dispersive layer;
forming a photoresist layer over the silicon anti-reflective coating layer, the photoresist layer defining a pattern;
etching to transfer the pattern to the hard mask layer; and
stripping at least the optical dispersive layer and the sacrificial layer;
wherein the sacrificial layer comprises an amorphous carbon material and extends over a side portion of the hard mask layer.
2. The method according to claim 1 , wherein the etching includes etching through the sacrificial layer to the hard mask layer, which results in completely removing the silicon anti-reflective coating layer during the etching.
3. The method according to claim 1 , comprising partially removing the silicon anti-reflective coating layer during the etching, and completely removing any remaining portion of the silicon anti-reflective coating layer during stripping.
4. The method according to claim 1 , comprising etching the sacrificial layer with an etchant having low selectivity to the silicon anti-reflective coating layer.
5. The method according to claim 4 , comprising etching the sacrificial layer with one or more of hydrogen bromide based chemistry, fluorine based chemistry, and chlorine based chemistry.
6. The method according to claim 4 , comprising:
transferring the pattern from the sacrificial layer to the hard mask layer; and
removing the sacrificial layer.
7. The method according to claim 6 , further comprising etching the silicon substrate to form the pattern therein.
8. The method according to claim 1 , comprising forming the sacrificial layer at a thickness of 50 Å to 500 Å.
9. The method according to claim 1 , wherein no or substantially no residue from the silicon anti-reflective coating layer remains after the stripping.
10. The method according to claim 1 , further comprising:
forming a high-κ dielectric material layer over the silicon substrate;
forming a titanium nitride layer over the high-κ dielectric material layer;
forming an amorphous silicon layer over the titanium nitride layer; and
forming the hard mask layer on the amorphous silicon layer.