Diamond-like carbon as mandrel
A method of fabricating a semiconductor structure is described. The method comprises forming at least one mandrel on a substrate, the at least one mandrel comprising a diamond-like carbon and having a top and two opposing sidewalls, the diamond-like carbon comprising at least 40% sp 3 hybridized carbon atoms. The mandrel may be used in Self-Aligned Multiple Patterning (SAMP) processes.
1. A method of fabricating a semiconductor structure, the method comprising:
forming a film stack on a substrate by plasma enhanced chemical vapor deposition (PECYD) at a temperature ranging from −50° C. to 600° C. and a pressure ranging from 0.1 mTorr to 10 Torr, the film stack comprising a pre-mandrel material;
forming a barrier layer on a top surface of the pre-mandrel material, the bather layer comprising spin-on-carbon;
forming a mask layer on a portion of a top surface of the barrier layer;
removing the barrier layer and pre-mandrel material that is not covered by the mask layer;
removing the mask layer and the barrier layer that is covered by the mask layer to form at least one mandrel on a silicon-containing layer formed on a titanium nitride layer on the substrate, the at least one mandrel comprising a diamond-like carbon and having a top surface and two opposing sidewalls, the diamond-like carbon comprising at least 40% spa hybridized carbon atoms;
depositing at least one layer of a spacer film on the at least one mandrel;
etching the spacer film from the top surface of the at least one mandrel leaving the spacer film on the two opposing sidewalls of the at least one mandrel;
removing the at least one mandrel to leave the spacer film from the two opposing sidewalls of the at least one mandrel and expose portions of the silicon-containing layer; and
etching the exposed portions of the silicon-containing layer to form adjacent pairs of substrate features.
2. The method of claim 1 , wherein the diamond-like carbon is etch selective and strip selective over spin-on-carbon (SOC).
3. The method of claim 1 , wherein the diamond-like carbon has a stress less than −500 MPa.
4. The method of claim 1 , wherein the diamond-like carbon has a density greater than 1.8 g/cc.
5. The method of claim 1 , wherein the diamond-like carbon comprises from about 50% to about 90% sp 3 hybridized carbon atoms.
6. The method of claim 1 , wherein the diamond-like carbon comprises about 60% sp 3 hybridized carbon atoms.
7. The method of claim 1 , wherein the diamond-like carbon has a Young's modulus greater than 150 GPa, measured at room temperature.
8. The method of claim 1 , wherein the at least one mandrel is formed by pulsed plasma enhanced chemical vapor deposition (PECVD).
9. The method of claim 1 , wherein the spacer film comprises silicon oxide.
10. The method of claim 1 , wherein the spacer film is a bather layer comprising spin-on-carbon (SOC).