Nitroxide mediated polymerization for narrow molecular weight distribution copolymers: application to photoresist materials

为了压印微电子产品的亚微米特征，光刻技术被用来用对辐射敏感的聚合物来刻蚀所需的图案(例如。光刻胶)。曝光后，由于溶解度的变化，光致抗蚀剂通过化学处理产生图案。决定特征大小的因素，如线宽分辨率(LWR)，取决于所使用的聚合物类型和聚合物的性质。通常，使用两个或两个以上单体的常规自由基聚合来制造光致抗蚀剂所需的共聚物。然而，这种聚合方法不能很好地控制链结构，而链结构是轻水反应堆的关键。可控自由基聚合(CRP)本质上使用自由基化学，但可以非常严格地控制分子量分布和微观结构。一些C反应蛋白方法(如RAFT，ATRP)已被应用于光致抗蚀剂材料，但其主要缺点是缺乏透明度，需要去除催化剂和链转移剂。我们的目标是应用另一种名为NMP的CRP变种，这种变种不会使聚合物变色，但仍可提供受控的微观结构。然而，NMP还没有应用于光致抗蚀剂。我们的项目将首先评估NMP化学作为光致抗蚀剂聚合物的一条途径，该聚合物可能用于193 nm光致抗蚀剂，由ST-Jean光电化学公司(SJPC)作为工业赞助商。SJPC将为微电子行业的利基材料提供聚合化学和放大设施方面的专业知识。

To imprint sub-micron features for microelectronics, photolithography is used to etch the desired pattern with polymers that are sensitive to the irradiation (eg. photoresists). After exposure, patterns are developed by chemical treatment from the photoresists due to solubility changes. Factors such as line width resolution (LWR) that determine feature size depend on the type of polymer used and the properties of the polymer. Typically, conventional free radical polymerization of two or more monomers is used to make the desired copolymer for the photoresist. However, such a polymerization method does not control chain structure well, which is critical for LWR. Controlled radical polymerization (CRP) uses essentially free radical chemistry but can control molecular weight distribution and microstructure very tightly. Some CRP methods (eg. RAFT, ATRP) have been applied for photoresist materials but the major disadvantage is their lack of transparency and they require catalyst and chain transfer agent removal. We aim to apply another variant of CRP termed NMP, which does not leave polymers discoloured but still provides controlled microstructure. NMP has however not been applied towards photoresists. Our project will first evaluate NMP chemistry as a route towards photoresist polymer potentially for 193 nm photoresists with St-Jean Photochemicals Inc. (SJPC) as the industrial sponsor. SJPC will provide their expertise in polymerization chemistry and scale-up facilities for niche materials in the microelectronics industry.