Thin Film Transfer Process for Low Cost Mcm-D Fabrication

This paper describes a unique, highly flexible and 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 and later transferring the thin film stack 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 Re 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 economy of scales and full utilization of the thin film factory for a variety of customer needs.