Combined surface activated bonding using H-containing HCOOH vapor treatment for Cu/Adhesive hybrid bonding at below 200 °C
Abstract
Cu/adhesive hybrid bonding is an attractive approach to three-dimensional (3D) integration because it provides direct Cusbnd Cu vertical interconnects and high mechanical stability. However, Cu/adhesive hybrid bonding at below 200 °C is still challenging because of bonding temperature mismatch between Cusbnd Cu and polymer adhesives and lacking of effective adhesive-compatible Cu surface activation methods. In this paper, we investigate and demonstrate a ;Cu-first; hybrid bonding technique by using hydrogen(H)-containing formic acid (HCOOH) vapor prebonding surface treatment for the first time. In this technique, high-quality Cusbnd Cu bonding is obtained at 180-200 °C that is close to or even lower than the temperature of subsequent adhesive curing. We experimentally investigate the effects of the H-containing HCOOH vapor treatment for Cusbnd Cu bonding and cyclo-olefin polymer adhesive-adhesive bonding. This technique enables Cu/adhesive hybrid bonding at below 200 °C, promising smaller thermal stress, higher throughput, and lower cost comparing to the existing ;adhesive-first; hybrid bonding method.
- Publication:
-
Applied Surface Science
- Pub Date:
- August 2017
- DOI:
- 10.1016/j.apsusc.2017.03.168
- Bibcode:
- 2017ApSS..414..163H
- Keywords:
-
- Cu/adhesive hybrid bonding;
- Surface activation;
- H-containing HCOOH vapor treatment;
- Surface activated bonding;
- 3D integration