Planar magnetron sputtering cathode with deposition rate distribution controllability

A new planar magnetron sputtering cathode was developed in order to reduce the change in the film thickness distribution on the substrate with time. This cathode has two (inner and outer) electromagnet coils coaxially wound on a magnetic yoke behind the target plate. The zero point in the vertical component of the magnetic field in front of the target can be moved by controlling the currents in the two coils. A glow discharge ring between 116 and 160 nm in diameter was obtainable with a target of diameter 254 mm. The deposition rate was higher at the centre of the substrate when the diameter of the glow discharge ring was smaller and vice versa. In order to synthesize a flat distribution two deposition rate distributions were summed on the substrate in such a manner that the glow discharge ring was periodically controlled to have a diameter of 116 and 160 mm ten times during deposition of 1 μm of Al-2%Si. A distribution deviation of ±5% was maintained during the deposition of 2200 μm onto substrates 125 mm in diameter.