Evolution of microstructure and electrical conductivity of electroless copper deposits on a glass substrate

Abstract

This paper describes the evolution of the microstructure and conductivity of electroless copper deposition on a glass substrate for applications in electronics manufacture. The glass was activated using a (3-aminopropyl)trimethoxysilane pre-treatment followed by a Pd/Sn catalyst. Surface morphology of the deposited copper films was characterized using a dual beam focused ion beam field emission scanning electron microscope, and together with atomic force microscopy, showed clearly that the roughness and grain size tended to increase with the plating time. Film thickness measurements showed a high initial deposition rate, which slowed to a constant level as the thickness increased above 100nm. This corresponded with the resistivity of the films which decreased rapidly as the thickness increased from 20 to 100nm, but then remained largely stable at a level approximately twice that of bulk copper.