Method of sputtering sequentially from a plurality of cathodes

Claim 1

THE METHOD OF APPLYING A COATING TO AN ARTICLE DISPOSED IN A COATING APPARATUS HAVING A CHAMBER WITH AN ATMOSPHERE OF AN INERT GAS AT LOW PERSSURE CONTAINED WITHIN SAID CHAMBER, ELECTRODES COMPRISING A CATHODE, AN ANODE AND AT LEAST TWO TARGET ELECTRODES IMMERSED IN SAID INERT GAS, AND CIRCUIT MEANS FOR APPLYING A BIASING POTENTIAL TO SAID ARTICLE AND TO SAID ELECTRODES, SAID METHOD COMPRISING THE STEPS OF (A) ENERGIZING SAID CATHODE TO PROVIE A SUPPLY OF FREE ELECTRONS, (B) BIASING SAID ANODE SO AS TO ACCELERATE SAID FREE ELECTRONS THROUGH SAID INERT GAS TO INOZIE ATOMS THEREOF, (C) VARIABLY BIASING SAID TARGET ELECTRODES TO ATTRACT INOIZED ATOMS OF SAID INERT GAS SO AS TO SPUTTER THEREFROM ATOMS OF SAID TARGET ELECTRODES, SAID BIASING STEP BEING PARTICULARLY CARRIED OUT BY INITIALLY BIASING SAID TARGET ELECTRODES SO THAT THE SPUTTERING RATE FROM ONE OF SAID TARGET ELECTRODES IS SUBSTNTIALLY ZERO WHILE THE SPUTTERING RATE FROM ANOTHER OF SAID TARGET ELECTRODES IS AT A PREDETERMINED LEBEL GREATER THAN ZERO, CHANGING THE BIAS ON SAID ONE TARGET ELECTRODE TO INCREASE THE SPUTTERING RATE THEREFROM WHILE CONTINUING TO SPUTTER ATOMS FROM SAID OTHER TARGET ELECTRODE, AND SIMULTANEOUSLY CONTROLLABLY CHANGING THE ON BIAS ON SAID OTHER TARGET ELECTRODE TO REDUCE THE SPUTTERING RATE THEREFROM TO SUBSTANTIALLY ZERO, AND (D) DE-ENERGIZING THE APPARATUS AT A FINITE TIME AFTER THE SPUTTERING RATE FROM SAID OTHER TARGET ELECTRODE REACHES SUBSTANTIALLY ZERO.

Claim 2

THE METHOD OF APPLYING A COATING TO AN ARTICLE DISPOSED IN A COATING APPARATUS HAVING A CHAMBER WITH AN ATMOSPHERE OF AN INERT GAS AT LOW PERSSURE CONTAINED WITHIN SAID CHAMBER, ELECTRODES COMPRISING A CATHODE, AN ANODE AND AT LEAST TWO TARGET ELECTRODES IMMERSED IN SAID INERT GAS, AND CIRCUIT MEANS FOR APPLYING A BIASING POTENTIAL TO SAID ARTICLE AND TO SAID ELECTRODES, SAID METHOD COMPRISING THE STEPS OF (A) ENERGIZING SAID CATHODE TO PROVIE A SUPPLY OF FREE ELECTRONS, (B) BIASING SAID ANODE SO AS TO ACCELERATE SAID FREE ELECTRONS THROUGH SAID INERT GAS TO INOZIE ATOMS THEREOF, (C) VARIABLY BIASING SAID TARGET ELECTRODES TO ATTRACT INOIZED ATOMS OF SAID INERT GAS SO AS TO SPUTTER THEREFROM ATOMS OF SAID TARGET ELECTRODES, SAID BIASING STEP BEING PARTICULARLY CARRIED OUT BY INITIALLY BIASING SAID TARGET ELECTRODES SO THAT THE SPUTTERING RATE FROM ONE OF SAID TARGET ELECTRODES IS SUBSTNTIALLY ZERO WHILE THE SPUTTERING RATE FROM ANOTHER OF SAID TARGET ELECTRODES IS AT A PREDETERMINED LEBEL GREATER THAN ZERO, CHANGING THE BIAS ON SAID ONE TARGET ELECTRODE TO INCREASE THE SPUTTERING RATE THEREFROM WHILE CONTINUING TO SPUTTER ATOMS FROM SAID OTHER TARGET ELECTRODE, AND SIMULTANEOUSLY CONTROLLABLY CHANGING THE ON BIAS ON SAID OTHER TARGET ELECTRODE TO REDUCE THE SPUTTERING RATE THEREFROM TO SUBSTANTIALLY ZERO, AND (D) DE-ENERGIZING THE APPARATUS AT A FINITE TIME AFTER THE SPUTTERING RATE FROM SAID OTHER TARGET ELECTRODE REACHES SUBSTANTIALLY ZERO.