In nanoimprint lithography, a release agent on the mold surface is usually necessary for easy demolding between the mold and the imprinted (thermal) resist. In this work, the thermal stability of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) monolayers is studied using x-ray photoelectron spectroscopy. The FDTS monolayers are deposited on Si (100) substrates via vapor phase reactions. Significant fluorine desorption of the monolayers is observed for samples annealed at 250 and 300 °C in air. The fluorine coverage decreases as a function of annealing time at a given annealing temperature. The desorption is proposed to be dependent on the monolayer packing details and may be influenced by the intermolecular heat transfer. Removal of the CF3 groups is found to be faster than that of the CF2 group as evidenced by the CF2/CF3 peak area ratios that increase with the annealing time. Sessile drop water contact angle and fluorine coverage evolution results show that the estimated useful coating lifetime is 180 min when the samples are annealed at 300 °C and ∼560 min when annealed at 250 °C. The peak position of the binding energy of the F 1s spectral line is related to the monolayer fluorine coverage and it may be a result of the interactions between the molecular chain and the negatively charged silicon substrate. Furthermore, nearly no chain desorption is detected for samples annealed in an inert environment, which may be attributed to the elimination of reactive oxygen and moisture molecules. The thermal degradation behaviors in ambient and inert atmosphere provide useful information for designing a nanoimprint process for the commercial manufacturing of polymeric microstructure and nanostructure.

中文翻译：

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自组装单层表面活性剂在硅基片上的热降解行为

在纳米压印光刻中，模具表面通常需要脱模剂，以方便模具和压印（热）抗蚀剂之间的脱模。在这项工作中，使用 X 射线光电子能谱研究了 1H,1H,2H,2H-全氟癸基三氯硅烷 (FDTS) 单层的热稳定性。FDTS 单层通过气相反应沉积在 Si (100) 衬底上。对于在空气中在 250 和 300 °C 下退火的样品，观察到单层的显着氟解吸。在给定的退火温度下，氟覆盖率作为退火时间的函数而降低。建议解吸取决于单层填充细节，并可能受分子间热传递的影响。发现 CF3 基团的去除速度比 CF2 基团的去除速度快，正如随退火时间增加的 CF2/CF3 峰面积比所证明的那样。固滴水接触角和氟覆盖率演变结果表明，当样品在 300°C 下退火时，估计的有用涂层寿命为 180 分钟，在 250°C 下退火时约为 560 分钟。F 1s 谱线结合能的峰值位置与单层氟覆盖率有关，可能是分子链与带负电荷的硅衬底相互作用的结果。此外，在惰性环境中退火的样品几乎没有检测到链解吸，这可能归因于活性氧和水分分子的消除。