Characterization of Low-Temperature Selective Cobalt Atomic Layer Deposition (ALD) for Chip Bonding

Abstract

A Cu-Cu bonding approach using low temperature (200 °C) selective Co ALD is demonstrated for Cu pads that are separated by 200 nm. The bonding testbed is characterized before and after Co ALD by SEM and EDS to confirm the feasibility of the approach. AFM and XPS are used to measure the selectivity of Co ALD on Cu and SiO2 surfaces.