Reactive Ion Etcher for cryo processes

康斯坦茨大学(University Of Konstanz)的中央纳米结构实验室(Nan.lab)申请了反应离子刻蚀设备，该设备将从2001年起取代现有的设备，并将扩大纳米实验室的可能性。现有的设备仅用于非常特殊和非常各向同性的蚀刻工艺，因为它针对在高工艺压力下工作进行了优化。各向异性刻蚀轮廓不能用现有设备实现。即使在另一个现有的、相对较年轻的工厂中，使用氟化学的各向异性蚀刻轮廓也只能在非常有限的程度上实现，并且不能对进一步的工艺类型进行改造。除了各向同性蚀刻，新设备还应允许高度各向异性的蚀刻工艺。这些蚀刻工艺对于纳米机械项目和硅基光波导的生产尤为重要。对于这些各向异性工艺，将使用聚合物形成工艺气体，从而使侧壁能够钝化。除了通常的射频源外，新设施将配备一个电感耦合等离子体(ICP)源。使用电感耦合等离子体使即使在非常低的工艺压力下也能保证气体中具有高密度离子和自由基的稳定等离子体成为可能。即将到来的研究项目的另一个重要优势是等离子体密度和离子能量(直流偏置)在刻蚀过程中的独立可调，这是由电感耦合等离子体提供的。这使得在低离子能量下进行刻蚀成为可能，缺陷很少，而且非常有选择性，这也提供了对刻蚀轮廓的最佳控制。这项技术绕过了为高度各向异性工艺而建立的专利且极其耗时的“博世工艺”。新工厂将完全使用氟气运行，现有工厂将专门用于未来的氯工艺，以实现工艺的必要重复性，并能够更有效地使用设备。有了这两家工厂，可以为物理和化学领域的广泛用户非常精确地干法蚀刻非常广泛的材料。这些结构的生产需要高精度的生产才能实施这些项目。为了确保这一点，有必要对相关工艺参数进行最大限度的控制。因此，工厂的设备应包括衬底电极的温度控制，以确保结果的重现性。可以在很宽的温度范围内控制的衬底电极也可以显著扩展系统的应用范围，因为化学反应活性可以通过温度来控制。激光干涉仪将允许就地监测蚀刻深度。此外，系统应配备干泵，以保证无油和清洁的工作。

The central nanostructure laboratory of the University of Konstanz (nano.lab) applies for reactive ion etching facility, which will replace an existing device from 2001 and will expand the possibilities of the nano.lab. The existing plant is only used for very special and very isotropic etching processes, as it is optimized for working under high process pressures. Anisotropic etching profiles cannot be realized with the existing equipment. Even in another existing, somewhat younger plant, anisotropic etching profiles using fluorine chemistry are only possible to a very limited extent and further process types cannot be retrofitted. In addition to isotropic etching, the new facility should also allow highly anisotropic etching processes. These etching processes are particularly important for projects in nanomechanics and the production of silicon-based optical waveguides. For these anisotropic processes, polymer-forming process gases are to be used, which enable the sidewalls to be passivated.In addition to the usual radiofrequency source the new facility will be equipped with an ICP (Inductively Coupled Plasma) source. The use of an ICP makes it possible to guarantee a stable plasma with a high density of ions and radicals in the gas even at very low process pressures. Another important advantage for the upcoming research projects is the independent adjustability of plasma density and ion energy (DC bias) during the etching process, which is given by the ICP. This makes it possible to etch at low ion energies with very few defects and very selectively, which also provides optimal control of the etching profiles. This is a technique that bypasses the patented and extremely time-consuming "Bosch process", which has been established for highly anisotropic processes.The new plant is to be operated exclusively with fluorine gases, and the existing plant is to be used exclusively for chlorine processes in the future in order to achieve the necessary reproducibility of the processes and to be able to use the equipment more efficiently. With these two plants, a very wide range of materials can be dry-etched very precisely for a wide range of users in the fields of physics and chemistry.A high degree of precision in the production of the structures is necessary for the implementation of the projects. To ensure this, it is necessary to have maximum control over the relevant process parameters. The equipment of the plant should therefore include a temperature control of the substrate electrode to ensure reproducibility of the results. A substrate electrode that can be controlled over a wide temperature range can also significantly extend the range of applications of the system, since the chemical reactivity can be controlled via the temperature. A laser interferometer will allow in-situ monitoring of the etching depth. In addition, the system should be equipped with dry pumps to guarantee oil-free and clean work.