Cyclic Block Copolymers for Controlling Feature Sizes in Block Copolymer Lithography

Abstract

Block copolymer lithography holds promise as a next-generation technique to achieve the sub-20 nm feature sizes demanded by semiconductor roadmaps. While molecular weight and block immiscibility have traditionally been used to control feature size, this study demonstrates that macromolecular architecture is also a powerful tool for tuning domain spacing. To demonstrate this concept, a new synthetic strategy for cyclic block polymers based on highly efficient "click" coupling of difunctional linear chains is developed, and the thin film self-assembly of cyclic polystyrene-block-polyethylene oxide (cPS-b-PEO) is compared with the corresponding linear analogues. The reduced hydrodynamic radii of the cyclic systems result in ~30% decrease in domain spacing over the corresponding linear polymers.

Ring and Linear Copolymer Blends under Confinement

“…[27][28][29] In a recent experimental study, R-CPs are used to control domain spacing which in the case of linear(L)-CPs relies on molecular weight and immiscibility as a parameter to control, and thus establish the fact that chain architecture is also an important tool for tuning domain spacing and other features. [30] Ring CPs can be prepared for example by a combination of atom transfer radical polymerization and click cyclization. [31] Although both L-CP and R-CP show the same nature of order-disorder transition they differ in many respect due to the difference in their topology: two chain ends for L-CP Vs no chain ends for R-CP.…”

Hydrogel formation by the ‘topological conversion’ of cyclic PLA–PEO block copolymers

“…6,7 In recent years, much success has been reported in further developing their functionality, 8 such as improved heat resistance in micelles, 9, 10 the control of micelle particle diameters, 11 and controlling domain intervals. 12 Increasing attention is being paid to such efforts.…”

Sub-20 nm Microphase-Separated Structures in Hybrid Block Copolymers Consisting of Polycaprolactone and Maltoheptaose

“…Some pioneering studies on the morphological properties of BCPs with nonlinear architectures, such as macrocyclic BCPs [16], dendritic-linear BCPs [17,18], (AB) n -type star BCPs [19,20], and miktoarm star polymers [21,22], have shown that the nonlinear architecture strongly affected their microphase-separated structures. Among them, the miktoarm star polymers, defined as star-shaped polymers consisting of more than two chemically different polymer chains, have drawn considerable attention because they show unique and unusual morphologies that differ from those of the corresponding linear counterpart.…”