An investigation of electroless copper films deposited on glass

This paper describes the characterization of electroless copper deposition on glass substrates with respect to surface morphology and adhesion. Silanisation of the glass surfaces with (3-aminopropyl)-trimethoxysilane (APTS) was used to provide a surface-coupled layer of functional molecules to assist in the improvement of adhesion of a Pd/Sn catalyst and the subsequent copper deposition. Surface morphology of the deposited films was characterized by field emission scanning electron microscopy (SEM) and together with atomic force microscopy (AFM), showed that the roughness and grain size tended to increase with the plating time. Tape peel testing was used to assess the adhesion of the coatings. All the deposits prepared with an electroless bath temperature of 40degC with a thickness up to 150 nm were found to adhere well to the glass substrate. Copper films were peeled off easily with increased thickness. This paper focuses on the development of thin copper films (Lt 200 nm thick) and considers the early stages of deposition in order to investigate further the role of the catalyst on adhesion.