A VACUUM TREATMENT APPARATUS, A BIAS POWER SUPPLY AND A METHOD OF OPERATING A VACUUM TREATMENT APPARATUS

摘要

A vacuum treatment apparatus (10) for treating at least one substrate (12) and comprising a treatment chamber (14), at least one cathode (16), a power supply (18) associated with the cathode for generating ions of a material present in the gas phase in the chamber and/or ions of a material of which the cathode is formed, a substrate carrier (20) and a bias power supply for applying a negative bias to the substrate carrier and any substrate present thereon, whereby to attract said ions to said at least one substrate, said cathode power supply being adapted to apply relatively high power pulses of relatively short duration to said cathode at intervals resulting in lower average power levels comparable with DC operation, e.g. in the range from ca. 1 KW to 100 KW, is characterized in that the bias power supply is adapted to permit a bias current to flow at a level corresponding generally to the average power level, and in that an additional voltage supply of relatively low inductive and resistive impedance is associated with the bias power supply for supplying a bias voltage adapted to the power of the relatively high power pulses when said relatively high power pulses are applied to said at least one cathode.