Polyphthalaldehyde is a self-developing resist material for electron beam and thermal scanning probe lithography (t-SPL). Removing the resist in situ (during the lithography process itself) simplifies processing and enables direct pattern inspection, however, at the price of a low etch resistance of the resist. To convert the material into a etch resistant hard mask, we study the selective cyclic infiltration of trimethyl-aluminum (TMA)/water into polyphthalaldehyde. It is found that TMA diffuses homogeneously through the resist, leading to material expansion and formation of aluminum oxide concurrent to the exposure to water and the degradation of the polyphthalaldehyde polymer. The plasma etch resistance of the infiltrated resist is significantly improved, as well as its stability. Using a silicon substrate coated with 13 nm silicon nitride and 7 nm cross-linked polystyrene, high resolution polyphthalaldehyde patterning is performed using t-SPL. After TMA/H₂O infiltration, it is demonstrated that pattern transfer into silicon can be achieved with good fidelity for structures as small as 10 nm, enabling >10× amplification and low surface roughness. The presented results demonstrate a simplified use of polyphthalaldehyde resist, targeting feature scales at nanometer range, and suggest that trimethyl-aluminum infiltration can be applied to other resist-based lithography techniques.

中文翻译：

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将图案化的有机抗蚀剂转换为用于高分辨率图案转移的高性能无机硬掩模

聚苯二醛是一种用于电子束和热扫描探针光刻（t-SPL）的自显影抗蚀剂材料。原位去除抗蚀剂（在光刻工艺本身期间）简化了工艺，并且能够进行直接图案检查，但是，以抗蚀剂的低蚀刻电阻为代价。要将材料转换为耐腐蚀的硬掩模，我们研究了三甲基铝（TMA）/水向聚苯二醛的选择性循环渗透。发现TMA通过抗蚀剂均匀扩散，导致材料膨胀和氧化铝的形成，同时暴露于水和聚邻苯二甲醛聚合物的降解。渗透的抗蚀剂的抗等离子体蚀刻性及其稳定性得到显着改善。使用涂有13 nm氮化硅和7 nm交联聚苯乙烯的硅基板，使用t-SPL进行高分辨率聚邻苯二甲醛图案化。在TMA / H _2之后通过渗入，证明对于低至10 nm的结构，可以以良好的保真度实现向硅的图案转移，从而实现大于10倍的放大倍率和较低的表面粗糙度。提出的结果证明了聚邻苯二甲醛抗蚀剂的简化用途，其目标尺寸范围为纳米范围，并且表明三甲基铝浸润可应用于其他基于抗蚀剂的光刻技术。