Self-formed Barrier using Cu-Mn Alloy Seed applied to a 400nm Pitch Wafer-to-Wafer Hybrid Bonding Technology

Abstract

We demonstrate the use of a self-formed MnOx barrier system in a 400nm pitch wafer-to-wafer hybrid bonding technology. By careful tuning of certain critical steps, among them the hybrid pad copper polish, we achieve high electrical yield on large hybrid bonded daisy chain structures. Dielectric breakdown, copper diffusion, Cu bulge-out and electromigration mechanisms of the self-formed barrier concept are extensively analyzed.