Magnetron sputtering cathode for low power density operation

T Motomura,T Tabaru

doi:10.1063/1.5013341

Abstract

A novel magnetron sputtering cathode with a magnetic mirror configuration is proposed, for low power density operation. The magnetic field profiles are simply constructed using two cylindrical permanent magnets positioned behind the disk-shaped sputtering target of 50 mm in diameter. The magnetic mirror configuration near the center and the outer edges of the target enables low power density operation up to 0.25 W/cm2 in the case of DC input power of 5 W. A sputtering rate of ∼0.2 nm/min was obtained under experimental conditions with target-substrate distance of 280 mm, Ar gas pressure of 0.1 Pa, and DC input power of 15 W.

Highlights

In conventional magnetron sputtering discharges, Ez × Br drift motion forms a doughnut-shaped plasma discharge region on the target surface
From the viewpoint of magnetron sputtering process efficiency, the design of the magnetic field profile is highly important because the electric-field lines generally align in a vertical direction with respect to the target surface
Many approaches have been followed to improve plasma confinement efficiency and low power density sputtering process results, a conventional planar magnetron cathode with a simple configuration is widely used in industry

Summary

INTRODUCTION

In conventional magnetron sputtering discharges, Ez × Br drift motion forms a doughnut-shaped plasma discharge region on the target surface. The doughnut-shaped plasma discharge contributes to plasma confinement on the target surface, and this more efficient plasma confinement enables operation at lower input power for plasma production, meaning that sputtering at lower power density is possible. The power density (W/cm2) is generally defined as the input power divided by the target area. A sputtering process with low power density is useful to obtain a very smooth surface and preferential orientation of the grains.[1,2] From the viewpoint of magnetron sputtering process efficiency, the design of the magnetic field profile is highly important because the electric-field lines generally align in a vertical direction with respect to the target surface. A novel planar magnetron sputtering cathode with magnetic mirror configuration is proposed, for low power density operation

EXPERIMENTAL SETUP

RESULTS AND DISCUSSION

CONCLUSION