Pulse packet switching for reactive magnetron sputtering. A new method to control the process

Reactive magnetron sputtering of SiO2, Al2O3, TiO2, Nb2O5 was applicable for mass pro-duction of optical layer stacks onto large substrate size since dual magnetron systems (DMS) with powering of the magnetron discharge in the 10 to 70 kHz frequency range were developed. The reactive process for deposition of high isolating, low refractive and transparent SiO2 using silicon targets in an argon/oxygen atmosphere was not as long term stable as other reactive processes because of arcing. Developments of sine wave and pulse power supplies with arc detection and extinguishing units were made. Long term behavior was improved but still each arc produces particles in the films and the reactive process will be interrupted during the shut off time of the power supply. Pulse packet switching mode for powering a dual magnetron system contains two op-erating frequencies - pulse and polarity changing frequency. The pulse packet switch-ing mode offers a new method of arc handling permitting a continuous running of the reactive process. The target containing the area where the arc occurred can be dis-charged and cooled down during a number of pulses. Arcs will be extinguished soon as they occur. No burn out of charged areas will be necessary anymore.