Shear-Rolling Process for Unidirectionally and Perpendicularly Oriented Sub-10-nm Block Copolymer Patterns on the 4 in Scale

Abstract

Shear alignment of the block copolymer (BCP) thin film is one of the promising directed self-assembly (DSA) methodologies for the unidirectional alignment of sub-10 nm microdomains of BCPs for next-generation nanolithography and nanowire-grid polarizers. However, because of the differences in the surface/interfacial energies at the top surface/bottom interface, the shear-induced ordering of BCP nanopatterns has been restricted to BCPs with spherical and cylindrical nanopatterns and cannot be realized for high-aspect-ratio perpendicular lamellar structures, which is essential for practical application to semiconductor pattern processes. It is still a difficult challenge to fabricate the unidirectional alignment in a short time over a large area. In this study, we propose an approach for combining the shear-rolling process with the filtered plasma treatment of BCP films for the fabrication of unidirectionally aligned and perpendicularly oriented lamellar nanostructures. This approach enables fabrication within 1 min on a 4 in scale. We treated filtered plasma on the BCP film for perpendicular orientation and executed the hot-rolling process with different roller and stage speeds. Large-scale shear was generated only at the location where the BCP film was in contact with both the roller and stage, effectively applying shear stress to a large area of the BCP film within a short time. The repeated application of this shear-rolling process can achieve a higher level of unidirectional alignment. Our aligned BCP vertical lamellae were used to fabricate a high-aspect-ratio sub-10nm-wide metallic nanowire array via dry/wet processes. In addition, shear-rolling with chemoepitaxy patterns can achieve higher orientational order and lower defectivity.

Chiral Plasmonic Nanowaves by Tilted Assembly of Unidirectionally Aligned Block Copolymers with Buckling-Induced Microwrinkles

“…For the unidirectional alignment of the BCP nanopatterns, a 0.8 mm-thick PDMS pad (Sylgard 184, Dow-Corning Ltd., 5:1 base:curing agent ratio, curing at 60 °C for 24 h) was conformably placed onto the BCP film, and the shear-rolling process was then performed repeatedly at 155 °C with a roller speed of 10 mm·s –1 and stage speed of 8 mm·s –1 for the sequential application of shear. Details of the shear-rolling instrument and procedure were described in our previous study …”

“…Details of the shear-rolling instrument and procedure were described in our previous study. 33 Preparation of PDMS Substrates and Tilted Transfer of BCP Thin Films. The precursor and curing agent of polydimethylsiloxane (PDMS, Sylgard 184, Dow-Corning Ltd.) were mixed (w/w: 10/1) and poured into a Petri dish, and the mixture was cured at 60 °C for 4 h in a convection oven.…”

“…Therefore, several methods, such as graphoepitaxy, chemoepitaxy, , and shear alignment, , for directed self-assembly that guide the BCP nanodomains into desired layouts have been studied. Recently, we reported a shear-rolling process capable of the unidirectional alignment of BCP nanodomains on the Si wafer scale in 1 min . By performing hot rolling with different speeds between the stage and roller, a large shear was sequentially applied to the BCP thin film as a big wave, enabling the successful unidirectional alignment of nanodomains with an orientation order of 0.98 at a very high speed over a large area.…”

From Lab to Fab: Enabling Enhanced Control of Block Polymer Thin-Film Nanostructures

“…Although many DSA techniques have been investigated, these technologies have not significantly transitioned into industrial processes. Shear alignment approaches have been demonstrated with various polymer systems, and the modes of operation have expanded over time to function with different means of applying shear and plasticization. ,,,, One form of shear alignment involves lateral displacement of the elastomer while the system is heated to temperatures above the T g s of the polymer blocks. − Another version uses solvent vapor, and instead of lateral displacement, the shear is produced by the solvent drying front contracting the elastomeric pad. ,, Although both approaches generate well-aligned patterns, they are slow and restricted to operation in batch mode. As with the discussion on annealing, the development of fast and continuous processing operations is critical to industrial adoption (Table ).…”

“…Shear alignment approaches have been demonstrated with various polymer systems, and the modes of operation have expanded over time to function with different means of applying shear and plasticization. 52,54,55,63,93 One form of shear alignment involves lateral displacement of the elastomer while the system is heated to temperatures above the T g s of the polymer blocks. 54−56 Another version uses solvent vapor, and instead of lateral displacement, the shear is produced by the solvent drying front contracting the elastomeric pad.…”