Techniques for precision pattern transfer of carbon nanotubes from photo mask to wafers
View Patent ↗A method for patterning CNTs on a wafer wherein a CNT layer is provided on a substrate, a hard mask film is deposited on the CNT layer, a BARC layer (optional) is coated on the hard mask film, and a resist is patterned on the BARC layer (or directly on the hard mask film if the BARC layer is not included). Then, the resist pattern is effectively transferred to the hard mask film by etching the BARC layer (if provided) and etching partly into, but not entirely through, the hard mask film (i.e., etching is stopped before reaching the CNT layer) Then, the resist and the BARC layer (if provided) is stripped, and the hard mask pattern is effectively transferred to the CNTs by etching away (preferably by using Cl, F plasma) the portions of the hard mask which have been already partially etched away.
1. A method of patterning CNTs on a substrate comprising:
providing the substrate, wherein the substrate has a CNT layer thereon;
depositing a hard mask film on the CNT layer;
coating a BARC layer on the hard mask film;
patterning a resist on the BARC layer;
etching the BARC layer;
etching partly into, but not entirely through, the hard mask film, whereby etching is stopped before reaching the CNT layer;
stripping the resist and the BARC layer; and
etching away portions of the hard mask which have been already partially etched away.
2. A method as recited in claim 1 , wherein the step of etching the BARC layer comprises using O 2 plasma or other plasma such as Cl, F.
3. A method as recited in claim 1 , wherein the step of etching partly into, but not entirely through, the hard mask film, comprises using F or Cl based plasma.
4. A method as recited in claim 1 , wherein the step of stripping the resist and the BARC layer comprises using O 2 plasma.
5. A method as recited in claim 1 , wherein the step of etching away portions of the hard mask which have been already partially etched away comprises using no O 2 plasma.
6. A method as recited in claim 1 , wherein the step of etching away portions of the hard mask which have been already partially etched away comprises using low O 2 plasma.
7. A method as recited in claim 1 , wherein the step of depositing a hard mask film on the CNT layer comprises depositing a single layer hard mask, and wherein said step of etching partly into, but not entirely through, the hard mask film comprises etching away less than all of a thickness of said single layer.
8. A method as recited in claim 1 , wherein the step of depositing a hard mask film on the CNT layer comprises depositing a multiple layer hard mask, and wherein said step of etching partly into, but not entirely through, the hard mask film comprises etching away less than all the layers of the hard mask film.
9. A method of patterning CNTs on a substrate comprising:
providing the substrate, wherein the substrate has a CNT layer thereon;
depositing a hard mask film on the CNT layer;
patterning a resist on the CNT layer;
etching partly into, but not entirely through, the hard mask film, whereby etching is stopped before reaching the CNT layer;
stripping the resist; and
etching away portions of the hard mask which have been already partially etched away.
10. A method as recited in claim 9 , wherein the step of etching partly into, but not entirely through, the hard mask film, comprises using F or Cl-based plasma.
11. A method as recited in claim 9 , wherein the step of stripping the resist and comprises using O 2 plasma.
12. A method as recited in claim 9 , wherein the step of etching away portions of the hard mask which have been already partially etched away comprises using no O 2 plasma.
13. A method as recited in claim 9 , wherein the step of etching away portions of the hard mask which have been already partially etched away comprises using low O 2 plasma.
14. A method as recited in claim 9 , wherein the step of depositing a hard mask film on the CNT layer comprises depositing a single layer hard mask, and wherein said step of etching partly into, but not entirely through, the hard mask film comprises etching away less than all of a thickness of said single layer.
15. A method as recited in claim 9 , wherein the step of depositing a hard mask film on the CNT layer comprises depositing a multiple layer hard mask, and wherein said step of etching partly into, but not entirely through, the hard mask film comprises etching away less than all the layers of the hard mask film.