Sputtering target assembly having solid-phase bonded interface

A three-layer sputtering target assembly comprising a sputtering target, a backing plate and at least one insert interposed therebetween, the sputtering target, the at least one insert and the backing plate having bonded interfaces therebetween, wherein the sputtering target is made of a material selected from the group consisting of a refractory metal of W, Mo, Ti, Ta, Zr and Nb, refractory metal-based alloys, silicides of the refractory metal, and Al and Al alloys;

• said backing plate is made of a material selected from the group consisting of Cu and Cu alloys, Al and Al alloys, stainless steels, and Ti and Ti alloys;
• and said at least one insert is made of a material selected from the group consisting of Cu and Cu alloys, Al and Al alloys, Ag and Ag alloys, and Ni and Ni alloys, characterized by said bonded interfaces being solid-phase bonded interfaces wherein any thermal diffusion layer present at said bonded interface has a thickness of 0-1 .mu.m, and by said sputtering target having uniform microstructure and crystal orientation with crystal grain sizes of no more than 350 .mu.m, with the provisio that no bonded interface has facing materials selected from the group consisting of Al and Al alloys, said target assembly having been formed by solid-phase bonding under the conditions of a vacuum of 1 Pa or less, a pressure load of 1 to 20 kg/mm.sup.2 and a temperature of 150.degree. to 350.degree. C. so that the coarsening of crystal grains and the change of crystal orientation in the target material arc prevented.