Modelling and Analytical Stability Analysis of Feedback Controlled Reactive Sputter Processes
(Room Room 104-B)
01 May 19
11:20 AM
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11:40 AM
Tracks:
Large Area Coatings
Reactive sputter deposition is a key technique used in large area coatings. Feedback control systems are integral to the efficient and stable operation of reactive sputtering processes, especially in the case of large area coatings. The typical feedback control system design process for reactive sputtering is usually based on experience rather than analytical calculations. This can lead to extended process setup time caused by prolonged tuning of controller parameters or fundamental instability due to the system design. Therefore, it is useful to develop a method that is able to analytically predict the stability and performance of the feedback controlled process. The results of the analysis are presented as novel visualizations of the complex relationship between closed-loop stability and process parameters, such as pumping speed, power, gas delivery arrangement and MFC speed. Furthermore, the analysis method is quantitative and the procedure can be automated, with the potential to optimize process parameters for stable control at the design stage and quickly troubleshoot the cause of stability problems and propose solutions when the process is in operation. An experimental case study is presented using an AlOx deposition process. This provides validation for the analysis method and describes examples of its practical application.