Plasma Characteristics and Target Erosion profile of Racetrack-shaped RF Magnetron Plasma with weak rubber magnets for full Circular Target Utilization

Significance Statement

Magnetron sputtering is an important method for depositing functional thin film. Magnetron sputtering plasma, a derivative of magnetron sputtering is used to produce high-density ring-shaped magnetized plasma, its utilization is said to be low at 20-30% and cannot be used effectively as target.

Despite the great work of previous researchers to improve the target utilization, which is estimated as the ratio of cross-sectional area eroded to area calculated by the product of the maximum eroded depth and target diameter, their work is said to be deficient as it fails reduce cost and to effectively use resources.

Professor Yasunori Ohtsu and colleagues from Japan proposed to improve the target erosion by rotating the racetrack-shaped magnetron plasma. The research work is published in Surface and Coatings Technology.

Utilization of the rubber magnet has an advantage of cost reduction of the equipment and reduction of electrical energy. The team came up with target erosion by rotating the racetrack-shaped magnetron plasma and make use of rubber magnets in place of the conventional metal magnets, due to the ability of rubber magnet to reduce the weight of the magnets.

According to the authors, two magnetic rubber material such as ferrite and neodymium are examined for production of racetrack shaped magnetron plasma. The ion saturation current which is proportional to the ion flux flowing to the target was detected by a probe current-voltage curve. The discharged voltage was measured from peak to peak value by high voltage probe and digital storage oscilloscope. The research was based on the comparing neodymium rubber magnets and neodymium metal magnets.

The research team found out that axial distribution of magnetic flux density decreases with increasing distance from the target, while keeping radial distribution. They also observed that neodymium metal magnets due to their discharge characteristics were found effective for plasma production. Their result reveals that ion flux to the target has a maximum at gap between two rubber magnets and the value increases by the addition of neodymium metal magnets.

The target utilization rate obtained in this work was higher than that obtained in the conventional magnetron sputtering. This can be seen as an improvement to the previous work.

Plasma Characteristics and Target Erosion profile of Racetrack-shaped RF Magnetron Plasma with weak rubber magnets for full Circular Target Utilization - Advances in Engineering

About The Author

Yasunori Ohtsu received his B.E, M.E and Ph. D degrees in Electrical Engineering in 1989, 1991 and 1997, respectively from Saga University, Saga, Japan.

He is currently a Professor with the Department of Electrical and Electronic Engineering, Graduate School of Science and Engineering, Saga University. His research interest is development of novel plasma sources by radio frequency discharge for material processing.

Journal Reference

Yasunori Ohtsu1, Shohei Tsuruta1, Tatsuo Tabaru2, Morito Akiyama2, Plasma Characteristics and Target Erosion profile of Racetrack-shaped RF Magnetron Plasma with weak rubber magnets for full Circular Target Utilization, Surface & Coatings Technology 307 (2016) 1134 –1138.

Show Affiliations
  1. Department of Electrical and Electronic Engineering, Graduate School of Science and Technology, Saga University, 1 Honjo-machi, Saga 840-8502, Japan
  2. Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, 807-1 Shuku, Tosu, Saga 841-0052, Japan

 

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