Abstract: Sputter target assemblies (10) and methods of making the sputter target assemblies in which the HIP processes conventionally used are minimized, or eliminated, while producing higher yields of sputter target assemblies in less time. In one instance the sputter target assemblies include a single, or multiple, layered interlayer (14, 16) between the target and backing plate (18) in order to achieve intermetallic diffusion bonds between adjacent layers during a single HIP process. A mechanical interlock between the target (12) and backing plate is also achieved preferably during a single HIP process. In another instance, the target and backing plate are welded directly together by electron beam welding, and the interlayer and HIP process are omitted. In either case, the process for making the sputter target assembly is shortened, rendering it less expensive and subject to less failures, while achieving assemblies having robust strength.