Local confined laser-induced plasmas for direct writing of low damage patterns by precise reactive etching

随着越来越多的集成和小型化以扩展表面和薄膜的功能，需要新的材料，但也需要新的创新技术来进行局部改性，图像化和沉积。在过去的几年里，激光技术已经发展到提高激光加工的精度，使新的应用。目前的激光加工优先利用物理过程，如激光诱导熔化、蒸发和烧蚀。提出的项目的目标是研究激光诱导反应等离子体（LIP），并评估它们对具有极高质量和低缺陷密度的表面的微加工。LIP与表面之间的相互作用机制可以是化学或物理性质的，但迄今为止通常研究的是物理相互作用。因此，我们关注的是激光诱导等离子体产生的激发化学反应自由基，这些等离子体应该用于特定形状激光束焦点下的局部化学自由基蚀刻。要回答的主要问题包括：(1)在不损伤表面的情况下引导脉冲高强度激光沿着表面并同时使近表面LIP形成；(2)在大气压力下，激光诱导等离子体优先从含有合适前体分子的气体混合物中产生活性自由基；(3)将LIP产生的活性物质输送到样品表面并与样品表面发生化学反应。通过对激光诱导等离子体蚀刻工艺参数依赖性的表面修饰和蚀刻实验研究，以及优先光学原位诊断对反应产物形成、输运和衰变的研究，揭示了激光诱导等离子体蚀刻的相关过程，建立了激光诱导等离子体蚀刻机理。所选过程的模拟应有助于验证这些过程和机制的相关性。这种激光诱导的反应等离子体可以实现局部分解，化学支持的表面加工，用于各种应用。

With increasing integration and miniaturisation for extending the functionality of surfaces and thin films new materials are required but also new, innovative technologies for local modification, patterning and deposition are requested. Within the last years laser technologies have been developed to increase the precision of laser machining for enabling new applications. The current laser processing preferentially makes use of physical processes like laser-induced melting and evaporation and ablation. The goal of the proposed project is to investigate laser induced reactive plasmas (LIP) and evaluate them for micromachining of surfaces with an extremely high quality and a low defect density. The interaction mechanism between the LIP and surfaces can be of chemical or physical nature however typically physical interactions have been investigated until now. Hence, we focus on the generation of excited chemical reactive radicals by laser induced plasmas that should be employed for local chemical radical etching beneath the focal point of a particular shaped laser beam. Main questions to be answered cover the areas of (i) guiding of the pulsed, high intense laser light along the surface without surface damage and enabling near surface LIP formation at the same time, (ii) generation of reactive radicals from a gas mixture containing suitable precursor molecules by laser induced plasmas preferentially at atmospheric pressure, and (iii) transport of the LIP generated reactive species to and chemical reaction of them with the samples surface. By the results of the experimental work that should be accomplished by studying the surface modification and etching in dependence on LIP process parameters and investigating the formation, transport and decay of reactive products by preferentially optical in situ diagnostics are utilized to expose the involved processes and establish a mechanism of laser induced plasma etching. The simulation of selected processes should provide help for verifying the relevance of these processes and mechanism. Such laser induced reactive plasmas could enable locally resolved, chemical supported machining of surfaces for a variety of applications.