Abstract: This invention is directed to an improved bonded sputter target/backing plate assembly and a method of making these assemblies. The assembly includes a sputter target having side and bottom bonding surfaces bonded within a recess in an underlying backing plate, the recess having top and side bonding surfaces. The method of forming the bonded assembly includes treating the bonding surfaces of either the sputter target or backing plate recess by roughening at least a portion of the bonding surfaces so as to produce a roughened portion having a surface roughness (R.sub.a) of at least about 120 micro-inches. The method further includes orienting the sputter target within the backing plate recess to form one assembly having a parallel interface defined by the top and bottom bonding surfaces and a side interface defined by the side bonding surfaces, subjecting the assembly to a controlled atmosphere, heating the assembly, and pressing the assembly so as to bond the bonding surfaces.