Lithographically Defined Cross-Linkable Top Coats for Nanomanufacturing with High-χ Block Copolymers

The directed self-assembly (DSA) of block copolymers (BCPs) is a powerful method for the manufacture of high-resolution features. Critical issues remain to be addressed for successful implementation of DSA, such as dewetting and controlled orientation of BCP domains through physicochemical manipulations at the BCP interfaces, and the spatial positioning and registration of the BCP features. Here, we introduce novel top-coat (TC) materials designed to undergo cross-linking reactions triggered by thermal or photoactivation processes. The cross-linked TC layer with adjusted composition induces a mechanical confinement of the BCP layer, suppressing its dewetting while promoting perpendicular orientation of BCP domains. The selection of areas of interest with perpendicular features is performed directly on the patternable TC layer via a lithography step and leverages attractive integration pathways for the generation of locally controlled BCP patterns and nanostructured BCP multilayers

Plasma etching processes of a sub-10 nm resolution high-X block copolymer self-assembled into spin-on-carbon trenches

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On‐Demand Editing of Surface Properties of Microstructures Made by 3D Direct Laser Writing via Photo‐Mediated RAFT Polymerization

International audienceRecently, photo-controlled reversible addition-fragmentation chain transfer (RAFT) polymerization has been successfully applied in digital light processing 3D printing. It provides a convenient way to tune the surface properties of the 3D printed object. However, so far, 3D micro- and nanostructures and reconfigurations based on photo-induced RAFT polymerization have not been presented. In this work, one macro-photoiniferter, synthesized by photocontrolled RAFT polymerization is applied, to 3D direct laser writing. Thanks to the exquisite spatial control of the photoreaction, 3D microstructures with feature sizes of around 500 nm are successfully obtained. Taking advantage of the presence of dormant polymeric RAFT agents, photo-induced postmodification of the printed microstructures is highlighted via the elaboration of multi-chemistry patterns including thermo-responsive ones. These results open new perspectives in multi-material and 4D micro-printing

Dry-Etching Processes for High-Aspect-Ratio Features with Sub-10 nm Resolution High-χ Block Copolymers

International audienceDirected self-assembly of block copolymers (BCP) is a very attractive technique for the realization of functional nanostructures at high resolution. In this work, we developed full dry-etching strategies for BCP nanolithography using an 18 nm pitch lamellar silicon-containing block copolymer. Both an oxidizing Ar/O2 plasma and a nonoxidizing H2/N2 plasma are used to remove the topcoat material of our BCP stack and reveal the perpendicular lamellae. Under Ar/O2 plasma, an interfacial layer stops the etch process at the topcoat/BCP interface, which provides an etch-stop but also requires an additional CF4-based breakthrough plasma for further etching. This interfacial layer is not present in H2/N2. Increasing the H2/N2 ratio leads to more profound modifications of the silicon-containing lamellae, for which a chemistry in He/N2/O2 rather than Ar/O2 plasma produces a smoother and more regular lithographic mask. Finally, these features are successfully transferred into silicon, silicon-on-insulator, and silicon nitride substrates. This work highlights the performance of a silicon-containing block copolymer at 18 nm pitch to pattern relevant hard-mask materials for various applications, including microelectronics

Self-organization and dewetting kinetics in sub-10 nm diblock copolymer line/space lithography

International audienceIn this work, we investigated the self-assembly of a lamellar block copolymer (BCP) under different wetting conditions. We explored the influence of the chemical composition of under-layers and top-coats on the thin film stability, self-assembly kinetics and BCP domain orientation. Three different chemistries were chosen for these surface affinity modifiers and their composition was tuned in order to provide either neutral wetting (i.e. an out-of-plane lamellar structure), or affine wetting conditions (i.e. an in-plane lamellar structure) with respect to a sub-10 nm PS- b -PDMSB lamellar system. Using such controlled wetting configurations, the competition between the dewetting of the BCP layer and the self-organization kinetics was explored. We also evaluated the spreading parameter of the BCP films with respect to the configurations of surface-energy modifiers and demonstrated that BCP layers are intrinsically unstable to dewetting in a neutral configuration. Finally, the dewetting mechanisms were evaluated with respect to the different wetting configurations and we clearly observed that the rigidity of the top-coat is a key factor to delay BCP film instability

Multifunctional Top-Coats Strategy for DSA of High-χ Block Copolymers

International audienceA concept of patternable top-coats dedicated to directed self-assembly of high-χ block copolymers is detailed, where the design enables a crosslinking reaction triggered by thermal or photo-activation. Nanostructured BCP areas with controlled domains orientation are selected through a straightforward top-coat lithography step with unique integration pathways. Additionally, the crosslinked nature of the material enables the suppression of the BCP dewetting, while exhibiting exceptional capabilities for the construction of 3D stacks

Top-coats for scalable nano-manufacturing with high-χ block copolymers in lithographic applications

International audienceResults for the self-assembly of lamellar silicon-containing high-χ BCPs with innovative neutral topcoat design are presented. We demonstrate that these materials and associated processes are compatible with a standard lithographic process, and oriented toward a potential HVM. We show that this dedicated technology is able to guarantee the stability and planarity of the stack even at elevated self-assembly bake temperatures, and opens new opportunity in the fields of 3D BCPs stacks. Finally, we show interesting results for the etch-transfer of a lamellar BCP in silicon