Sputter deposition process

A process for enhancing magnetron cathode reactive sputtering of a low melting temperature metal with a reactive gas, comprising the steps of:

• installing the metal as a horizontal, upwardly facing, planar magnetron cathode target in a magnetron cathode sputtering chamber;
• applying sputtering power in the chamber and creating a plasma cloud of ions and electrons within the chamber to cause positive ions to bombard the target;
• melting the metal target and confining the molten metal to the surface of the cathode;
• sputtering the molten metal;
• introducing the reactive gas into the sputtering chamber for reaction with the sputtered metal;
• shielding marginal portions of the target from the plasma cloud and ion bombardment;
• and
• causing reaction products forming on the surface of the unshielded portions of the molten metal target to be moved to and collected within said shielded marginal portions thereby to maintain a clean molten metal sputtering surface on the unshielded portions of the target and to reduce the potential for arcing.

A process for magnetron cathode reactive sputtering of oxides and nitrides of low melting point metals chosen from bismuth, tin, gallium, and their alloys, comprising the steps of;

• installing the metal as a horizontal, upwardly facing, planar magnetron cathode target in a magnetron cathode sputtering chamber;
• evacuating the chamber;
• applying sputtering power in the chamber to create an active sputtering zone;
• melting the metal and confining the molten metal to the surface of the cathode;
• sputtering the molten metal in the active sputtering zone;
• introducing oxygen or nitrogen into the sputtering chamber for reaction with the sputtered metal;
• forming an inactive, non-sputtering zone in fluid communication with but outside of the active sputtering zone and shielding the inactive non-sputtering zone from the active sputtering zone;
• inducing circulation of the molten metal in the active sputtering zone;
• and
• causing oxides or nitrides forming on the surface of the molten bismuth, tin, gallium, or alloy thereof to be moved into the shielded inactive, non-sputtering zone thereby to maintain a clean molten metal sputtering surface in the active sputtering zone and to reduce the potential for arcing.

A process for magnetron cathode reactive sputter deposition of oxides and nitrides of low melting point metals chosen from bismuth, tin, gallium, and their alloys onto a web substrate within a magnetron cathode sputtering chamber which includes an unwind reel, a take-up reel, at least one chill drum and at least one planar magnetron cathode mounted horizontally below the chill drum, comprising the steps of:

• mounting a roll of web substrate material onto the unwind reel in the magnetron cathode sputtering chamber;
• guiding the web around the lower surface portions of the chill drum and onto the take-up reel;
• installing the low melting point metal on the cathode as a horizontal, upwardly facing, planar magnetron cathode target;
• evacuating the chamber;
• introducing one or more gases into the evacuated chamber, at least one of which gases is oxygen or nitrogen;
• moving the web through the chamber and around the chill drum;
• circulating coolant through the cathode and the chill drum to chill the same and the drum supported web substrate;
• applying sputtering power in the chamber and creating a plasma cloud of ions and electrons between the target and the drum supported portion of the web substrate to cause positive ions to bombard the target;
• melting the metal target and confining the molten metal to the upper surface of the cathode;
• sputtering the molten metal and depositing an oxide or a nitride of the metal onto the drum supported portion of the web substrate;
• forming an inactive, non-sputtering zone in communication with the molten target and shielding the non-sputtering zone from the plasma cloud and ion bombardment;
• and
• causing oxides or nitrides forming on the surface of the molten metal to move into the shielded non-sputtering zone thereby to maintain a clean sputtering surface on the molten metal and to reduce the potential for arcing;
• whereby coatings of oxides or nitrides of bismuth, tin, gallium, and their alloys may be deposited on the substrate at exceptionally high and consistent rates of deposition.