Thin film transfer process for low cost MCM-D fabrication

This paper describes a unique, highly flexible cost competitive method to fabricate microelectronic packages that require thin film interconnections. The method involves fabricating thin film metal/polymer structures multi-up on a reusable temporary glass carrier; the thin film stack is transferred later onto product substrates of choice. The final product substrate can be silicon, co-fired alumina or glass-ceramic, aluminum nitride, diamond, or a printed wiring board. Optionally, one can also use the released thin film decal as a flexible high wireability interconnect by itself, as an interposer, or in applications like wafer level testing for known good die (KGD). The thin film wiring structure can be fabricated multi-up on a standardized form factor carrier (independent of the characteristics of the final product substrate) in a thin film interconnect foundry, thus significantly reducing cost both from the economies of scale and full utilization of the thin film factory for a variety of customer needs