Non-bonded rotatable targets and their methods of sputtering

A cylindrical sputtering target, comprising:

• a tubular member having a length in a longitudinal direction and defining a tube surface;
• and,
• a source material positioned about the tube surface of the tubular member and forming a sputtering surface about the tubular member, wherein the source material defines an inner surface opposite of the sputtering surface and non-bonded to the tube surface of the tubular member, and wherein the inner surface of the source material is mechanically engaged to the tube surface of the tubular member,
• wherein the source material comprises a first cylindrical ring directly stacked onto a second cylindrical ring, wherein the first cylindrical ring defines a top surface positioned adjacent to a bottom surface of the second cylindrical ring, and wherein the top surface of the first cylindrical ring is mechanically engaged to the bottom surface the second cylindrical ring, and wherein the top surface of the first cylindrical ring defines a protrusion or a cavity that couples to a cavity or protrusion, respectively, defined in the bottom surface of the second cylindrical ring.