Multilayer film substrates with 30 μm vias for MCM applications

Recently, a new technology for the production of flexible multilayer substrates was been (Fach et al, Proc. FLEXCON, 1997). In this technology, multilayer circuits were fabricated on ceramic or glass substrates (6×6 inch) by using conventional thin film techniques. After finishing the multilayer structure, the layer stacks were removed from the reusable rigid carrier substrate by a previously deposited separation layer without applying force. This results in highly flexible foil-like objects with excellent mechanical and electrical properties. It is also possible to assemble and bond the components and to test the circuit while the film is still stuck to the rigid carrier substrate, avoiding the handling problems of conventional flexprints. The production steps for the multilayer substrates are largely compatible with those of known production processes for multichip modules (MCM-D). The unique combination of a flexible material with the properties of a MCM-D offers new applications in the broad field of electronic interconnect technologies, as well as in the worlds of sensors and microsystems. This paper is focused on the use of the new multilayer film substrates in multichip modules