A batch wafer scale LIGA assembly and packaging technique via diffusion bonding

A technique using diffusion bonding (or solid-state welding) has been used to achieve batch fabrication of two-level nickel LIGA structures. Interlayer alignment accuracy of less than 1 micron is achieved using press-fit gauge pins. A milli-scale torsion tester was built to measure the diffusion bond strength of LIGA formed specimens that has shown successful bonding at temperatures of 450/spl deg/C at 7 ksi pressure with resulting bond strength greater than 100 MPa. Extensions to this basic process to allow for additional layers and thereby more complex assemblies as well as commensurate packaging are discussed.