Circularly symmetric sputtering apparatus with hollow-cathode plasma devices

A sputtering apparatus for depositing thin films on substrates, said apparatus comprising:

• a process chamber having therein a central sputtering region and an annular plasma distribution region surrounding and open to the central sputtering region, wherein the central sputtering region is cylindrical in shape with two planar disk diodes forming opposite lateral sides thereof and a circumferential periphery thereof being open to and surrounded by the annular plasma distribution region, and wherein the central sputtering region and the annular plasma distribution region are coaxial to a process chamber axis;
• two planar disk diodes positioned in facing relationship in the sputtering region of the process chamber and coaxial to the process chamber axis, each planar disk diode having a sputtering target facing the central sputtering region in a plane normal to the process chamber axis;
• means for applying radiofrequency power to the planar disk diodes;
• positioning means for positioning a substrate within the central sputtering region between the two planar disk diodes in a plane normal to the process chamber axis;
• plasma generation means for generating and supplying plasma to the annular plasma distribution region of the process chamber for diffusion into the central sputtering region of the process chamber to create a substantially uniform plasma therein, said plasma generation means including two or more coldwall hollow-cathode plasma devices symmetrically disposed about and attached to the annular plasma distribution region of the process chamber, and wherein each coldwall hollow-cathode plasma device supplies a plasma of ionized gas through an outlet thereof to the annular plasma distribution region of the process chamber.

A method for depositing electrically conductive or insulating thin films on a substrate, said method comprising the steps of:

• providing a sputtering apparatus having a process chamber with a central sputtering region and an annular plasma distribution region surrounding and open to the central sputtering region, wherein both the central sputtering region and the annular plasma distribution region are substantially free from externally-applied magnetic fields;
• providing within the central sputtering region two planar disk diodes each having a target of material to be sputtered, wherein the sputtering target may be composed of either conductive or insulating material, and wherein the diodes define lateral boundaries of the central sputtering region of the process chamber;
• locating a substrate to be sputtered adjacent to and between the planar disk diodes in the central sputtering region;
• generating a plasma by two plasma-generating means located symmetrically outside the process chamber and supplying the plasma to the annular plasma distribution region of the process chamber for diffusion into the central sputtering region to create a substantially uniform plasma therein;
• and then
• providing radiofrequency power to the targets of the planar disk diodes to cause atoms to dislodge from the targets and form a thin film on the substrate.

A sputtering apparatus for depositing thin films on substrates, said apparatus comprising:

• a process chamber having therein a central sputtering region and an annular plasma distribution region surrounding and open to the central sputtering region, wherein both the central sputtering region and the annular plasma distribution region are substantially free from externally-applied magnetic fields;
• two planar disk diodes positioned in the central sputtering region of the process chamber and each having a sputtering target facing the central sputtering region;
• positioning means for positioning a substrate within the central sputtering region adjacent to the planar disk diode;
• and
• plasma generation means for generating and supplying plasma to the annular plasma distribution region of the process chamber for diffusion into the central sputtering region of the process chamber, said plasma generation means including two or more coldwall hollow-cathode plasma devices symmetrically disposed about and attached to the annular plasma distribution region of the process chamber, and wherein each coldwall hollow-cathode plasma device supplies a plasma of ionized gas through an outlet thereof to create a substantially uniform plasma within the annular plasma distribution region of the process chamber.