Method of manufacturing sputtering target assembly

A method of manufacturing a sputtering target assembly having a target member and a backing member capable of producing an assembly wherein during manufacture distortion of the sputtering target assembly is not greater than about 0.003-inches in the lateral direction and not greater than about 0.005-inches in the transverse direction, comprising:

• providing a target member having an upper lateral target surface, a lower end and a side wall with an inner surface and an outer surface;
• providing a backing member for the target member, said backing member having a top surface and a side wall with inner and outer surfaces, the top surface of the backing member being adapted to engage the lower end of the target member;
• providing a shoulder in the outer surface of the side wall of the target member that extends inwardly and downwardly from the outer surface at the lower end of the target member and terminates in a lip, one side of the lip being at the inner surface;
• positioning the top surface of the backing member within said shoulder of the target member so that said top surface is in surface-to-surface contact with the target member and the inner surface is in surface-to-surface contact with the lip, said side wall of said backing member being sized with respect to said shoulder so that the outer surface of the side wall of the backing member is substantially coextensive with the outer surface of the side wall of target member;
• firmly holding the target and backing members together and electron beam welding the surface-to-surface contact areas of said target and backing members;
• and
• machining the inner surface of the side wall of the backing member and the lip of the target member to remove the lip and provide a coextensive inner surface along the inner surfaces of the backing member and target member.