Orientation Control of Block Copolymers Using Surface Active, Phase-Preferential Additives

Abstract

Orientation control of thin film nanostructures derived from block copolymers (BCPs) are of great interest for various emerging technologies like separation membranes, nanopatterning, and energy storage. While many BCP compositions have been developed for these applications, perpendicular orientation of these BCP domains is still very challenging to achieve. Herein we report on a new, integration-friendly approach in which small amounts of a phase-preferential, surface active polymer (SAP) was used as an additive to a polycarbonate-containing BCP formulation to obtain perpendicularly oriented domains with 19 nm natural periodicity upon thermal annealing. In this work, the vertically oriented BCP domains were used to demonstrate next generation patterning applications for advanced semiconductor nodes. Furthermore, these domains were used to demonstrate pattern transfer into a hardmask layer via commonly used etch techniques and graphoepitaxy-based directed self-assembly using existing lithographic integration schemes. We believe that this novel formulation-based approach can easily be extended to other applications beyond nanopatterning.

Thermal Approaches to Perpendicular Block Copolymer Microdomains in Thin Films: A Review and Appraisal

“…These criteria restrict the applicability of random copolymers to only a certain family of BCPs, as can be inferred from the use of P(S-r-MMA) as neutral layers for non-PS-b-PMMA BCPs. [42,62,71,74,91] In this Macromol. Rapid Commun.…”

“…[54] Obviously, the segregation of fluorinated additives to only the free surface necessitated a separate substrate neutralization step. A similar but conceptually different work by Vora and Schmidt et al [62] used a hydrogen-bonding, fluorinated homopolymer to orient polystyrene-block-poly(methyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate) (PS-b-PMTC-Me) microdomains perpendicular on a P(S-r-MMA) neutral layer. Here, the additive localized selectively in the PMTC-Me domain via hydrogen bonding and segregated to the free surface where they lowered the γ of the polar block.…”

“…Of these reports, reports that promote perpendicular microdomains via thermal annealing are highly promising because they are easily reproducible and industry friendly. These methods include substrate modification, [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] use of top coats, [24,[47][48][49][50][51][52][53][54][55][56][57] incorporation of additives, [58][59][60][61][62][63][64] exploitation of the architecture effect, [65][66][67][68] use of modified [42,43,[69][70][71] or newly synthesized BCPs, [72][73][74]…”

Towards Automated Monomer Synthesis: A Streamlined Approach for the Synthesis of Cyclic Carbonates

“…Finally, the resulting monomers often require repeated purification since small impurities from the final step can initiate oligomerization of the carbonate monomer upon storage or affect the molecular weight distribution for an otherwise well-controlled polymerization. 21,24 To find an improved synthesis, our group has previously published the use of bis(pentafluorophenyl) carbonate to simultaneously cyclize bis-MPA and install an activated pentafluorophenyl ester handle for further functionalization ( Figure S1c). 19 Although this approach proved to be highly amenable to accessing a broad variety of functional carbonate monomers, the transesterification step provided 50-90% yields, needed extended reaction times, and required chromatographic purification to remove unreacted starting materials and byproducts.…”

Spatial arrangement of block copolymer nanopatterns using a photoactive homopolymer substrate

“…The resulting self-assembled nanostructures have been applied in a range of areas including in nanolithography, 2 electronic devices 7 and biomaterials. 6,8 In particular, owing to the ability to form sub-20 nm nanopatterns, [9][10][11][12][13][14][15] block copolymer selfassembly has emerged as a viable alternative approach to conventional photolithography with high potential for gaining industrial relevance. Compared to other high resolution lithography techniques such as extreme ultraviolet 16 and electron beam lithography, 17 block copolymer lithography has advantages of potentially high throughput and low cost, and has become one of the most important alternative next-generation lithography techniques.…”