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A novel high-χ block copolymer polystyrene-b-polycarbonate (PS-b-PC) of the same system with three samples (1, 2, 3) which contain an active -NH- group on the polymer backbone between the PS block and the PC block have been successfully synthesized. It is believed that the hydrogen bond between -NH- and Si-OH (silanol) plays a dominant role which is as a real driving force to promote vertical micro-phase separation under the neutral layer free condition. The periods in which the samples 1, 2 and 3 form a vertical layer micro-phase separation are 10.6, 11.2 and 12.3nm, respectively. Though experiments, the best micro-phase separation process conditions were found (annealing temperature 160-165°C; annealing time 10 min) and the relevant parameters of PS-b-PC are also given. The results show that sample 2 of high-χ (0.19) has better phase separation performance, lower line-edge roughness (LER) and line width roughness (LWR) than the other two samples. These diblock copolymer samples successfully achieved the directed self-assembly (DSA) of PS-b-PC under the condition that the designed silicon substrate groove did not need any neutral layer. Compared with the previously reported methods to orientation control BCPs with χ value and small vertical micro-phase separation while short-term thermal treatment demonstrates PS-b-PC as a rare and valuable candidate for advancing the field of nanolithography. This work will provide extremely important theories, valuable information and insights that apply to nanowire patterning by DSA in state-of-the-art semi-conduction devices.
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