Fine-Pitch UBM Pad Metallization and Flip-Chip Assembly for Plane Arrays Interconnection

摘要

We have developed and successfully obtained stable and reliable processes in our labs for metallization and pad definition of passivated Si substrates for microelectronic flip-chip assembly with solder bumps, applicable to high-density interconnection technology. Patterned samples were prepared with aluminum pads on Si/SiO2 over which the UBM multilayer metals were deposited. Pads are 90×90micron∧2 with 185micron pitch. All metal layers show good stability and adherence, and the final processes have good reproducibility and stability. A flip-chip assembly using solder micro-bumps deposited over the pads was used to demonstrate stability and reliability of the process. This set of processes -metallization, pad definition and flip-chip assembly - will next be applied to functional devices.