Plasma based process control of reactive sputtering

反应溅射常用于在低温等离子体中存款薄膜，作为各种高科技产品的基础。尽管其巨大的社会影响，许多基本的机制，如电子加热，等离子体表面相互作用，并在这样的等离子体传输现象不理解。因此，还缺乏对全局控制参数（例如中性气体压力、气体流量、功率、磁场等）对沉积薄膜的特性的非线性和非局部影响的了解。这导致过程优化和控制的巨大限制。由于缺乏对不同粒子种类的能量分布函数的理解和访问，其决定了膜特性，以及表面特性本身，当前工艺控制的概念是基于控制次级参数，例如气体辉光和功率，其不唯一地决定膜特性，以及灰箱模型。在这个意义上，等离子体溅射工艺是一个有代表性的例子，各种其他等离子体工艺，遭受同样的问题。在这个项目中，等离子体为基础的概念，即基于等离子体参数和科学的理解，控制反应溅射存款Al 2 O 3-薄膜在电容射频（RF）磁控管等离子体将首次开发和测试。一个基本的理解的全局控制参数的能量分布函数的不同粒子种类的影响，确定的薄膜特性，以及薄膜特性本身将开发的基础上的实验和理论方法的协同组合。放电的特点是实验上的各种等离子体和表面诊断，以及数值动力学模拟。基于这一基本认识，将确定适用于工艺控制的等离子体参数。这些参数必须在几秒钟内通过非侵入性诊断进行测量，并且必须与能量分布和表面特性唯一相关。它们将通过快速简化的全局模型从理论上进行描述，该模型可以预测寄生工艺漂移的原因和补偿它们的程序。这些等离子体参数和模型将用于并行开发的控制回路的框架中的过程控制。这种基于等离子体的控制回路将导致对沉积薄膜的特性的控制的显著改进。目标是控制等离子体特性，例如每个沉积颗粒的能量，以关联膜和等离子体特性，并最终控制膜特性。如果成功的话，基于等离子体的工艺控制的原理可以转移到其他等离子体工艺中。此外，对这种等离子体的物理学的重要的基本见解。

Reactive sputtering is frequently used to deposit thin films in low temperature plasmas as the basis for a variety of high-tech products. Despite its enormous societal impact many fundamental mechanisms such as the electron heating, plasma-surface interactions, and transport phenomena are not understood in such plasmas. Consequently, there is also a lack of insights into the non-linear and non-local effects of global control parameters such as the neutral gas pressure, gas flows, powers, magnetic fields, etc. on the characteristics of deposited thin films. This leads to massive limitations of process optimization and control. Due to a lack of understanding of and access to the energy distribution functions of different particle species, that determine the film properties, as well as to the surface characteristics themselves current concepts of process control are based on controlling secondary parameters such as gas glows and powers, which do not determine the film characteristics uniquely, as well as greybox-models. In this sense plasma sputter processes are a representative example of a variety of other plasma processes that suffer from the same problems.In this project, a plasma based concept, i.e. based on plasma parameters and scientific understanding, to control reactive sputtering to deposit Al2O3-films in a capacitive radio frequency (RF) magnetron plasma will be developed and tested for the first time. A fundamental understanding of the effects of global control parameters on energy distribution functions of different particle species, that determine the film characteristics, as well as of the film characteristics themselves will be developed based on a synergistic combination of experimental and theoretical methods. The discharge will be characterized experimentally by a variety of plasma and surface diagnostics as well as numerically by kinetic simulations. Based on this fundamental understanding capable plasma parameters suitable for process control will be identified. These parameters must be measurable within seconds by non-invasive diagnostics and must be uniquely correlated to energy distributions and surface characteristics. They will be described theoretically by fast reduced global models that can predict causes of parasitic process drifts and procedures to compensate them. These plasma parameters and models will be used for process control in the frame of a control loop that is developed in parallel. This plasma based control loop will result in a significant improvement of the control of the characteristics of deposited thin films. The goal is to control plasma characteristics such as the energy per deposited particle to correlate film and plasma characteristics and to ultimately control the film characteristics. If successful, this principle of plasma based process control can be transferred to other plasma processes. Moreover, important fundamental insights into the physics of such plasmas are expected.