Tzu-Hou Chan¹, Yao-Kuang Yang¹, Ju-Liang He^2,3, Ping-Yen Hsieh^{2,3, Ying-Hung Chen2,3, Thomas Schütte4, Ralf Bandorf3,5
1Dah Young Vacuum Equipment Co., Ltd., Taichung City, Taiwan
2Feng Chia University, Taichung City, Taiwan
3Fraunhofer Innovation Platform for Surface and Production Engineering for Optical and Electrical Systems at the Feng Chia University, Taichung City, Taiwan
4PLASUS GmbH, Mering, Germany
5Fraunhofer Institute for Surface Engineering and Thin Films IST, Braunschweig, Germany
Reactive sputtering techniques are widely utilized for depositing colorful decorative coatings in consumer and industrial products. It’s well known that the color of decorative coatings is highly influenced by their thickness and stoichiometry. However, traditional process development relies heavily on operator experience, lacking real-time plasma detection and control, which leads to increased costs and reduced product yield. This study addresses these challenges by introducing an optical emission spectroscopy (OES)-based feedback control system integrated into a production-scale batch-type reactive HiPIMS coater. This system enables real-time monitoring and active feedback control during TiON-based decorative film deposition, significantly enhancing film quality uniformity and ensuring batch-to-batch stability.
The study employed a DYHC 900 batch-type HiPIMS coater developed by DAH YOUNG Vacuum, featuring a vacuum chamber with an inner diameter and height of 900 mm. To successfully deposit TiON-based coatings, the equipment was equipped with a planar sputtering cathode using a titanium target measuring 631 mm in length. Argon served as the sputtering gas, while oxygen and nitrogen were used as reactive gases to produce decorative coatings in gold, red, and blue colors. Three collimators were strategically placed along the target at intervals of 220 mm to collect OES signals. Additionally, three gas distribution tubes were mounted along the target, each independently connected to a gas flow meter for precise control of reactive gas flow rates. During the HiPIMS-TiON coating deposition process, plasma signals were monitored and used for active feedback control of the reactive gas flow rates, ensuring spatial and temporal plasma distribution with signal variation below 5%. This verified the high OES signal consistency along the vertical direction of the target surface. Further, four runs in #1,3,5,7 were selected from a total of seven, and five samples were randomly chosen from each run, resulting in 20 samples for analysis. The results demonstrated that the thickness variation and color difference among the samples were controlled to within 10%.
In summary, this study demonstrates that the OES-based active feedback control system effectively enhances film quality uniformity and batch-to-batch stability on a production-scale batch-type reactive HiPIMS coater. This approach provides a self-adjusting mechanism for the equipment, significantly improving its capability for stable mass production.}