Process for producing a tube-shaped cathode sputtering target

A process for producing a tube-shaped cathode sputtering target with an oxygen concentration in an outer tube (target) of ≦100 ppm and with a structure composed of columnar crystallites that are aligned perpendicularly to the surface of the outer tube, the process comprising the steps of:

• producing a metallic inner tube (target holder) of a first material with a first melting point of Ts1≧900 K;
• producing a metallic outer tube (target) that concentrically surrounds the inner tube and is made of a second material with a second melting point of Ts2≦800 K, the tubes being produced so that an inside diameter of the outer tube and an outside diameter of the inner tube are proportioned in such a way that the two tubes fit together tightly and are mechanically firmly joined, the step of producing the outer tube including forming the outer tube by casting the second material in a molten state in a heated, vertical, cylindrical permanent mold, the inner tube forming a heated mandrel for the cylindrical mold;
• and, after a space between the mold and the inner tube has been filled with the molten second material, cooling the outer tube from inside to outside and from bottom to top by actively developing a first, radial thermal gradient between the inner tube and the mold and a second thermal, longitudinal gradient between a bottom and a top of the mold.