Colbeck Kirby Lauren, Lodha Jayant K, Astley Simon, Skelton Dave, Armini Silvia, Evans Andrew, Brady-Boyd Anita
Physics Department, Aberystwyth University, Aberystwyth SY23 3BZ, UK.
Semiconductor Technology and Systems, IMEC, Kapeldreef 75, B-3001 Leuven, Belgium.
Nanomaterials (Basel). 2024 Jun 5;14(11):982. doi: 10.3390/nano14110982.
Perfluorododecyl iodide (I-PFC12) is of interest for area-selective deposition (ASD) applications as it exhibits intriguing properties such as ultralow surface energy, the ability to modify silicon's band gap, low surface friction, and suitability for micro-contact patterning. Traditional photolithography is struggling to reach the required critical dimensions. This study investigates the potential of using I-PFC12 as a way to produce contrast between the growth area and non-growth areas of a surface subsequent to extreme ultraviolet (EUV) exposure. Once exposed to EUV, the I-PFC12 molecule should degrade with the help of the photocatalytic substrate, allowing for the subsequent selective deposition of the hard mask. The stability of a vapor-deposited I-PFC12 self-assembled monolayer (SAM) was examined when exposed to ambient light for extended periods of time by using X-ray photoelectron spectroscopy (XPS). Two substrates, SiO and TiO, are investigated to ascertain the suitability of using TiO as a photocatalytic active substrate. Following one month of exposure to light, the atomic concentrations showed a more substantial fluorine loss of 10.2% on the TiO in comparison to a 6.2% loss on the SiO substrate. This more pronounced defluorination seen on the TiO is attributed to its photocatalytic nature. Interestingly, different routes to degradation were observed for each substrate. Reference samples preserved in dark conditions with no light exposure for up to three months show little degradation on the SiO substrate, while no change is observed on the TiO substrate. The results reveal that the I-PFC12 SAM is an ideal candidate for resistless EUV lithography.
全氟十二烷基碘（I-PFC12）因其具有诸如超低表面能、改变硅带隙的能力、低表面摩擦以及适用于微接触图案化等有趣特性，而在区域选择性沉积（ASD）应用中备受关注。传统光刻技术正努力达到所需的关键尺寸。本研究探讨了使用I-PFC12在极紫外（EUV）曝光后在表面的生长区域和非生长区域之间产生对比度的潜力。一旦暴露于EUV，I-PFC12分子应在光催化基板的帮助下降解，从而允许随后选择性沉积硬掩膜。通过使用X射线光电子能谱（XPS），研究了气相沉积的I-PFC12自组装单层（SAM）在长时间暴露于环境光下的稳定性。研究了两种基板SiO和TiO，以确定使用TiO作为光催化活性基板的适用性。在暴露于光一个月后，原子浓度显示TiO上的氟损失更为显著，为10.2%，而SiO基板上的氟损失为6.2%。在TiO上观察到的这种更明显的脱氟归因于其光催化性质。有趣的是，观察到每种基板的降解途径不同。保存在黑暗条件下长达三个月未曝光的参考样品在SiO基板上几乎没有降解，而在TiO基板上未观察到变化。结果表明，I-PFC12 SAM是无抗蚀剂EUV光刻的理想候选材料。
