Cylindrical magnetron target and apparatus for affixing the target to a rotatable spindle assembly

An apparatus for affixing a cylindrical magnetron target to a rotatable support spindle, said apparatus comprising:

• a support spindle including a target attachment flange, said flange having both a rear face and a front face which incorporates a circumferential seal retention groove;
• an O-ring seal which fits into the seal retention groove, a circumferential portion of said seal extending beyond said groove;
• a cylindrical target having a spindle attachment end which mates with said target attachment flange, said spindle attachment end having a circumferential sealing surface which contacts said circumferential portion of said seal, said spindle attachment end also having a circumferential shoulder which terminates in an inwardly-angled, overhanging circumferential step that faces away from said spindle attachment end;
• a clamping collar comprised of arcuate segments, which are collectively sized to generally and coaxially surround said target attachment flange and said circumferential shoulder, said collar incorporating, both an inwardly-angled clamping ledge that engages the overhanging step of the target, and at least one internal spiral, circumferential thread spaced apart from said clamping ledge which overhangs and is angled away from said rear face;
• and
• a retainer ring sized so as to be slidable over the spindle, and rotatable against the rear face of the target attachment flange, said retainer ring incorporating external, spiral, circumferential threads that are angled away from the target attachment flange, the external threads of said retainer ring engaging the internal threads of said clamping collar to draw the clamping ledge and engaged target toward the flange and compress the O-ring seal as the retainer ring is rotated in a thread engaging direction.