A low-temperature solid-state bonding method using Ag-modified Cu microcones and Ag buffer

A novel low-temperature solid-state bonding method that Cu microcones coated with Ag and Ag buffer has been proposed. Thin Ag layer was used to prevent the oxidation of Cu microcones and Ag layer of several micrometers was used as a buffer layer between Cu microcones and Cu bumps. No brittle IMCs formed in the interfaces.