Evrard Quentin, Sadegh Najmeh, Mathew Simon, Zuidinga Ed, Watts Benjamin, Paradiz Dominguez Maximilian, Giglia Angelo, Mahne Nicola, Nannarone Stefano, Nishimura Akira, Goya Tsuyoshi, Sugioka Takuo, Vockenhuber Michaela, Ekinci Yasin, Brouwer Albert M
Advanced Research Center for Nanolithography ARCNL, Science Park 106, 1098 XG Amsterdam, The Netherlands.
van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam, The Netherlands.
ACS Appl Mater Interfaces. 2024 Aug 14;16(32):42947-42956. doi: 10.1021/acsami.4c08636. Epub 2024 Aug 5.
Organometallic tin-oxo-hydroxo cage compounds offer a promising photoresist platform for extreme ultraviolet photolithography (EUVL). Their reactivity is dominated by the facile breaking of the tin-carbon bonds upon photon or electron irradiation. As the cage is dicationic, it exists as a complex with anions for charge compensation. In the present work, we explore the -butyltin-oxo cage with two tetrakis(pentafluorophenyl)borate counteranions (TinPFPB). In contrast to the small counterions that are typically used, the bulky PFPB anion absorbs a substantial fraction (∼30%) of the impinging EUV radiation (13.5 nm, 92 eV), and it has its own reactivity upon photoionization. When thin films of the complex are irradiated with EUV radiation at low doses, a positive-tone development is possible, which is rather unique as all other known tin-oxo cage resists show a negative tone (cross-linking) behavior. We propose that the initial positive tone behavior is a result of the chemical modification of the Sn cluster by fragments of the borate anions. For comparison, we include the tetrakis(-tolyl)borate anion (TB) in the study, which has similar bulkiness, and its complex with the -butyltin-oxo cage (TinTB) shows the usual negative tone EUV resist behavior. This negative-tone behavior for our control experiment rules out a hypothesis based purely on the steric hindrance of the anion as the cause of the different EUV reactivity.
有机金属锡-氧-氢氧根笼状化合物为极紫外光刻（EUVL）提供了一个很有前景的光刻胶平台。它们的反应活性主要由光子或电子辐照下锡-碳键的容易断裂所主导。由于笼状结构带两个正电荷，它以与阴离子形成的配合物形式存在以进行电荷补偿。在本工作中，我们研究了带有两个四（五氟苯基）硼酸根抗衡阴离子（TinPFPB）的丁基锡-氧笼。与通常使用的小抗衡离子不同，体积较大的PFPB阴离子吸收了相当一部分（约30%）入射的极紫外辐射（13.5纳米，92电子伏特），并且它在光电离时具有自身的反应活性。当用低剂量的极紫外辐射照射该配合物的薄膜时，有可能实现正性显影，这相当独特，因为所有其他已知的锡-氧笼光刻胶都表现出负性（交联）行为。我们提出初始的正性显影行为是硼酸根阴离子碎片对锡簇进行化学修饰的结果。为作比较，我们在研究中纳入了四（对甲苯基）硼酸根阴离子（TB），它具有类似的体积，并且它与丁基锡-氧笼形成的配合物（TinTB）表现出通常的负性极紫外光刻胶行为。我们对照实验的这种负性显影行为排除了一种纯粹基于阴离子的空间位阻作为不同极紫外反应活性原因的假设。
