“…It was considered that the defect generation was attributable to resist functionality of PMMA weakened by exposure to UV light used to cause the benzophenone photochemistry and to remove a residual layer by UV/ozone. In previous reports on block copolymer lithography using PS-block-PMMA, PMMA regions are rapidly etched by oxygen plasma in dry etching in comparison with PS regions [12,13]. In our study, exposure to UV/ozone is used for removal of a residual layer as a dry etching process.…”
Section: Tuning Patterned Metal Line Width By Controlled Wet Side-etcmentioning
This article gives an overview of reactive-monolayer-assisted thermal nanoimprint lithography (R-TNIL) for the fabrication of patterned metal thin layers on substrates by simple wet etching using a thermoplastic polymer resist layer assisted by photochemically grafted polymer layer. A photoreactive monolayer causing a photoinduced graft reaction on the metal surface anchors interfacial resist polymers, resulting in the suppression of thermally induced dewetting of the resist layer and the improvement of lateral pattern resolution of metal thin layers. Line widths of metal patterns could be tuned by controlled side etching. Enhanced adhesion of resist layers was revealed by lateral force curves measured by scanning probe microscopy. It was demonstrated as an application that transparent conductive substrates having metal mesh structures were fabricated by R-TNIL. We also demonstrated R-TNIL involving electrodeposition, which allowed the preparation of metal patterns with controlled aspect ratio. It was proved that the photoreactive monolayer played important roles to fabricate submicrometer patterns of metal thin layers.
“…It was considered that the defect generation was attributable to resist functionality of PMMA weakened by exposure to UV light used to cause the benzophenone photochemistry and to remove a residual layer by UV/ozone. In previous reports on block copolymer lithography using PS-block-PMMA, PMMA regions are rapidly etched by oxygen plasma in dry etching in comparison with PS regions [12,13]. In our study, exposure to UV/ozone is used for removal of a residual layer as a dry etching process.…”
Section: Tuning Patterned Metal Line Width By Controlled Wet Side-etcmentioning
This article gives an overview of reactive-monolayer-assisted thermal nanoimprint lithography (R-TNIL) for the fabrication of patterned metal thin layers on substrates by simple wet etching using a thermoplastic polymer resist layer assisted by photochemically grafted polymer layer. A photoreactive monolayer causing a photoinduced graft reaction on the metal surface anchors interfacial resist polymers, resulting in the suppression of thermally induced dewetting of the resist layer and the improvement of lateral pattern resolution of metal thin layers. Line widths of metal patterns could be tuned by controlled side etching. Enhanced adhesion of resist layers was revealed by lateral force curves measured by scanning probe microscopy. It was demonstrated as an application that transparent conductive substrates having metal mesh structures were fabricated by R-TNIL. We also demonstrated R-TNIL involving electrodeposition, which allowed the preparation of metal patterns with controlled aspect ratio. It was proved that the photoreactive monolayer played important roles to fabricate submicrometer patterns of metal thin layers.
“…However, to be used as a next generation lithographic mask, BCPs must possess several important properties such as strongly segregating blocks, facile perpendicular orientation control on thin films, and high etch contrasts [2]. To that end, poly(styreneblock-methyl methacrylate) (PS-b-PMMA) has been well studied by researchers as it can be used to create highly ordered structures with a perpendicular orientation on thin films by using thermal annealing and a neutral layer to tailor the chemical properties of the substrate interface [3][4][5]. However, as the segregation strength of PS-b-PMMA is relatively weak, the minimum pattern dimension (L 0 ) that can be achieved is approximately 24 nm and thus sub-10 nm feature sizes cannot be obtained [6].…”
The directed self-assembly (DSA) of block copolymers (BCPs) has recently become a viable alternative technique for the nanofabrication of semiconductors. To facilitate pattern transfer onto silicon (Si) wafers from BCP masks, a novel class of Si-rich BCPs with hyperbranched polysiloxane side chains were synthesized in this report. The resistance to oxygen-reactive ion etching (O 2 -RIE) was quantified for the linear and modifiedhyperbranched polysiloxanes, revealing that the modified-hyperbranched polysiloxanes exhibited increased O 2 -RIE resistances. Furthermore, by tailoring the chemical properties on the end-groups of the polysiloxane side chains, atomic force microscopy (AFM) and scanning electron microscopy (SEM) studies revealed that perpendicularly-oriented lamellae could be observed on the thin films.
“…[12][13][14] However, to apply such materials for the lithographic process, high etching selectivity between the two composite polymers is required in order to transfer the pattern to the substrate. 15 In this work, we report a fabrication process of sub-10 nm line-and-space patterns using the DSA materials featuring high χ parameter and high etch selectivity. We applied one of the most promising DSA materials, namely, POSS containing DSA materials, to realize sub-10 nm line-and-space patterning processes.…”
Abstract. The perpendicularly orientated lamellar structure of the self-organized diblock copolymer is an attractive template for sub-10-nm line-and-space pattern formation. We propose a method of evaluating the neutral layer (NL) whose performance has an important bearing on the perpendicular orientation of the lamellar structure. The random copolymer of methyl methacrylate and i-butyl POSS methacrylate (MAIBPOSS) has been investigated as an NL for a polymethylmethacrylate-b-polymethacrylethylPOSS (PMMA-b-PMAIBPOSS) lamellar structure. PMMA-b-PMAIBPOSS material has the potential to form sub-10 nm line-and-space pattern, in addition to high etch selectivity due to its POSS structure. Under the free surface, PMMA-b-PMAIBPOSS film on the random copolymer layer showed horizontal orientation. However, a half-pitch of a 7-nm finger pattern structure was observed by peeling off the horizontally oriented layer. The upper portion of the PMMA-b-PMAIBPOSS film was eliminated till proximity of the random copolymer layer by CF 4 gas etching. From the result, it was revealed that the PMMA-r-PMAIBPOSS works as an NL. It was confirmed that the contact angle analysis using an appropriate polymer is a suitable method for evaluation of the surface energy performance of the copolymer with the attribute of high segregation energy.
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