Patent ID: 6096174
Filing Date: 2000-08-01
Classification: C23C,H01J,H01L

Abstract:
An apparatus for coating a substrate with a layer by cathode sputtering, said apparatus comprising:a process chamber containing a gas under a partial pressure, said process chamber supporting therein magnetron cathodes supporting respective targets for sputtering;a first voltage source for applying between the targets a voltage so as to sustain a gas discharge plasma to produce the ions necessary for said cathode sputtering;a circuit portion connecting the power source with the targets so that each target alternately forms the cathode and anode of the gas discharge;said circuit portion including an H bridge causing a reversal of current direction flowing to and from said targets;said H bridge comprising four switches and having two pairs of diagonal points each connected with a respective magnetron cathode supporting a respective target;a first conductor connecting a one portion of the H bridge to the positive pole of first voltage source,a second conductor connecting the positive pole of the first voltage source to an another portion of the H bridge, said second conductor including a choke; anda third conductor which branches from said first conductor being connected to the positive pole of a voltage means comprising a second voltage source or a charge storage means, said voltage means having a negative pole connected through a fifth switch to the process chamber, andsaid switches being operated by a control circuit in a regular and variable mode.