A Study on Chemical and Mechanical Properties of NiCrSn Films for Flexible Copper Interconnect

In this work, both the adhesion properties and chemical properties of new NiCrSn alloys as a copper diffusion barrier layer on polymer substrates were examined using micro-scratch tests. The metal/polymer interfaces were examined using auger electron spectroscopy and X-ray photoemission spectroscopy. Compared to Ni-20 at% Cr alloy, the Ni-16 at% Cr-4 at% Sn alloy films have higher values of adhesion forces than that of Ni-20 at% Cr. In addition, the Ni-16 at% Cr-4 at% Sn alloy shows better wet pattering performance without remaining etch residue after wet pattering in 33% FeCl₃ wet etchant. Such tendencies were explained in terms of the different types of metal oxide compounds forming at the metal/polymer interfaces which are dependent on the barrier metal's composition.