Muratov Mukhit, Shabelnikova Yana, Zaitsev Sergey, Nemkayeva Renata, Guseinov Nazim
Department of Physics and Technology, Al-Farabi Kazakh National University, 050040 Almaty, Kazakhstan.
Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Sciences, Chernogolovka, 142432 Moscow, Russia.
Micromachines (Basel). 2025 Aug 20;16(8):958. doi: 10.3390/mi16080958.
In this study, the key lithographic performance of PMMA 950K resist was evaluated by exposure to a 30 keV focused gallium (Ga) ion beam. The sensitivity and contrast of PMMA 950K were directly compared with those of electron exposure under identical development conditions. It was found that the sensitivity of PMMA 950K to Ga ions for 50 nm films reaches a value of about 0.4 μC/cm, which is more than 250 times higher than its sensitivity to electron exposure. A method for evaluating the resist contrast during ion exposure is proposed in this work, taking into account the highly non-uniform dose distribution across the resist depth; it yielded a contrast value of γ = 2.6, which is consistent with the result obtained with electron exposure (γ = 2.8). In addition, a pronounced dependence of the resist sensitivity on the resist thickness was found: with an increase in thickness from 10 nm to 60 nm the sensitivity decreases by an order of magnitude. The obtained results form a reliable methodological basis for characterizing the behavior of polymer resists under ion irradiation and provide valuable recommendations for optimizing lithography with a focused beam of Ga ions when creating nanostructures for microelectronics, photonics, and quantum technologies.
在本研究中，通过用30 keV聚焦镓（Ga）离子束曝光来评估PMMA 950K光刻胶的关键光刻性能。在相同的显影条件下，将PMMA 950K的灵敏度和对比度与电子曝光的灵敏度和对比度直接进行比较。结果发现，对于50 nm厚的薄膜，PMMA 950K对Ga离子的灵敏度达到约0.4 μC/cm，这比其对电子曝光的灵敏度高出250倍以上。考虑到光刻胶深度上剂量分布高度不均匀，本文提出了一种在离子曝光期间评估光刻胶对比度的方法；该方法得出的对比度值γ = 2.6，与电子曝光得到的结果（γ = 2.8）一致。此外，还发现光刻胶灵敏度对光刻胶厚度有显著依赖性：随着厚度从10 nm增加到60 nm，灵敏度降低了一个数量级。所获得的结果为表征聚合物光刻胶在离子辐照下的行为形成了可靠的方法基础，并为在为微电子、光子学和量子技术创建纳米结构时用聚焦Ga离子束优化光刻提供了有价值的建议。
