Double-Patterned Sidewall Directed Self-Assembly and Pattern Transfer of Sub-10 nm PTMSS-b-PMOSTby Cushen, Julia; Wan, Lei; Blachut, Gregory; Maher, Michael J.; Albrecht, Thomas R.; Ellison, Christopher J.; Willson, C. Grant; Ruiz, Ricardo
The directed self-assembly (DSA) of two sub-20 nm pitch: silicon-containing block copolymers (BCPs) was accomplished using, a double patterned sidewall scheme-in which each lithographic prepatterned feature produced two regions for pattern registration. In doing so, the critical dimension of the lithographic prepatterns was:relaxed by a factor of 2 compared to previously reported schemes for DSA. The key to enabling the double-patterned sidewall scheme is the exploitation of the oxidized sidewalls of cross-linked polystyrene formed, during the pattern transfer of the resist via reactive kin etching. This results in shallow trenches with two guiding interfaces per prepatterned feature. Electron loss spectroscopy was used to study and confirm the guiding mechanism of the double-patterned,sidewalls, and pattern transfer of the BCPs into a silicon substrate was achieved using reactive ion etching. The line edge roughness, width roughness, and placement error are near the target required for bit-patterned media applications, and the technique is also compatible with the needs of the semiconductor industry for high-volume manufacturing.