Bilayer polymer thin films, that form through the surface segregation of a surface-active component, provide the ability to tailor interfacial properties and are relevant to many technological applications, including photolithography. For example, polymers with fluorine-containing end groups will selectively accumulate at the polymer–air interface when the second polymer is not fluorinated, but what happens when both polymers in a bilayer film are fluorinated? To test this, we prepared polymers via reversible addition–fragmentation chain transfer (RAFT) polymerization, which were then end group modified with a fluorine-containing small molecule or by chain extension with a fluorinated monomer to form a short fluorine-containing block. These partially fluorinated polymers were then blended with an extreme ultraviolet (EUV) photoresist that had a degree of in-chain fluorination, and thin films of the blends were prepared. To probe multilayer formation and assess the competition of the end group modified, fluoro-block, and in-chain fluorinated groups for the polymer–air interface, the films were characterized using contact angle measurements and static time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results reveal important insights into the effect of fluoro-block length on directing self-segregation of the polymeric additive. The effect of the addition of the low surface energy polymer on the lithographic performance of the photoresist was confirmed using electron beam lithography.

中文翻译：

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使用低表面能聚合物控制功能性紫外线吸收剂在光刻胶聚合物表面的呈现


双层聚合物薄膜是通过表面活性成分的表面隔离形成的，具有定制界面特性的能力，并且与包括光刻在内的许多技术应用相关。例如，当第二种聚合物未氟化时，具有含氟端基的聚合物将选择性地在聚合物-空气界面处积聚，但是当双层膜中的两种聚合物都氟化时会发生什么？为了测试这一点，我们通过可逆加成-断裂链转移（RAFT）聚合制备了聚合物，然后用含氟小分子对聚合物进行端基修饰，或用氟化单体进行扩链以形成短的含氟嵌段。然后将这些部分氟化的聚合物与具有一定程度链内氟化的极紫外（EUV）光致抗蚀剂混合，并制备混合物的薄膜。为了探测多层形成并评估端基修饰、氟嵌段和链内氟化基团对聚合物-空气界面的竞争，使用接触角测量和静态飞行时间二次离子质谱法对薄膜进行了表征（ToF-SIMS）。结果揭示了氟嵌段长度对引导聚合物添加剂自分离的影响的重要见解。使用电子束光刻证实了添加低表面能聚合物对光刻胶光刻性能的影响。