Analyses of Photo-induced Surface Reaction Processes during Plasma Sputtering

本项目的目标是澄清反应等离子体溅射过程中光子注入（特别是紫外线：UV）到材料表面的作用。经验上已经知道，在反应等离子体溅射（即，反应性离子蚀刻）工艺中，光子注入显著影响溅射性能，但是光致非平衡表面化学反应的详细机制几乎不为人知。在本项目中，我们分析了各种蚀刻过程的表面反应机制，以澄清光子注入如何影响蚀刻性能，使用分子动力学（MD）模拟和质量选择离子束注入系统。特别是在本年度，即本项目的最后一年，我们进行了以下课题的研究：（1）分子动力学模拟中激发态原子的原子间势函数和光子与材料中原子相互作用的模型化。(2)基于从质量选择离子束注入系统获得的单能离子束和连接到离子束系统的UV光源的光的同时注入实验，检查离子束和光子注入的协同效应。通过这样的研究，我们已经评估了UV对反应离子蚀刻的影响（即，等离子体溅射），并阐明了在工业中广泛使用的材料（例如二氧化硅和某些有机聚合物）的反应离子蚀刻工艺期间表面反应的各种特性。

The goal of this project is to clarify the role of photon injections (especially those of ultra violet : UV) into the material surface during reactive plasma sputtering. It has been empirically known that, in reactive plasma sputtering (i.e., reactive ion etching) processes, photon injections significantly affect sputtering properties, but detailed mechanisms of the photo-induced non-equilibrium surface chemical reactions have been hardly known. In the present project, we have analyzed surface reaction mechanisms of various etching processes to clarify how photon injections can affect etching properties, using molecular dynamics (MD) simulations and a mass-selected ion beam injection system. Especially in this fiscal year, which is the final year of the present project, we have worked on the following topics : (1) Modeling of interatomic potential functions for excited atoms and interaction of photons and atoms in the material for MD simulations. (2) Examination of synergetic effects of ion beams and photon injections, based on the simultaneous injection experiments of a mono-energetic ion beam obtained from the mass selected ion beam injection system and light from a UV light source attached to the ion beam system. Through such research, we have evaluated effects of UV on reactive ion etching (i.e., plasma sputtering) and clarified various characteristics of surface reactions during reactive ion etching processes for materials widely used in the industry, such as silicon dioxide and some organic polymers.