A Universal Approach to Fabricating 3D Chemical Patterns for Directed Self-Assembly of Block Copolymers with Density Multiplication

Directed self-assembly (DSA) of block copolymers (BCPs)with densitymultiplication has been proved to be a viable technique for the fabricationof FinFET at the 7 nm node. The key to the realization of DSA withdensity multiplication is to control the interfacial energy betweenBCP and the underlying substrate. In this work, we report a universaland fab-compatible approach to fabricating 3D chemical patterns forDSA of BCPs with density multiplication by combining lithographicpatterning and plasma treatment. The surface energy of cross-linkedpolystyrene (XPS) mat could be tuned for controlling the wetting behaviorof BCP films by simply adjusting oxygen plasma treatment conditions.Non-preferential surfaces for poly (styrene-b-methylmethacrylate) (PS-b-PMMA), poly (styrene-b-methyl acrylate) (PS-b-PMA), poly (styrene-b-propylene carbonate) (PS-b-PPC), andpoly (styrene-b-(lactic acid-alt-glycolic acid))(PS-b-PGLA) are obtained by oxygen plasma treatment,which eliminates the use of random copolymer brushes in the LiNe flow.3D chemical patterns are successfully fabricated by combining e-Beampatterning of PMMA photoresist and oxygen plasma treatment, and DSAof lamellae-forming PS-b-PMMA and PS-b-PMA with up to 10x density multiplication is achieved on 3D chemicalpatterns.

Automated summary

In this work, a universal and fab-compatible approach to fabricating 3D chemical patterns for DSA of BCPs with density multiplication is proposed by combining lithographic patterning and plasma treatment. The wetting behavior of BCP films can be controlled by tuning the surface energy of cross-linked polystyrene (XPS) mat through adjusting oxygen plasma treatment conditions. Non-preferential surfaces for various BCPs are obtained by oxygen plasma treatment, eliminating the use of random copolymer brushes in the LiNe flow.