Electrical four point probing of silver thin films coated onto micron sized polymer spheres

TitleElectrical four point probing of silver thin films coated onto micron sized polymer spheres
Publication TypeJournal Article
Year of Publication2016
AuthorsPettersen, S. R., A. E. Stokkeland, H. Kristiansen, J. Njagi, K. Redford, D. V. Goia, Z. Zhang, and J. He
JournalApplied Physics Letters
Volume043103
Date Published07/2016
ISSN0003-6951
Keywords4-point-probing, electrical-characterization, nanoprobing, SEM, thin-film
Abstract

Micron-sized metal-coated polymer spheres are frequently used as filler particles in conductive composites for electronic interconnects. However, the intrinsic electrical resistivity of the spherical thin films has not been attainable due to deficiency in methods that eliminate the effect of contact resistance. In this work, a four-point probing method using vacuum compatible piezo-actuated micro robots was developed to directly investigate the electric properties of individual silver- coated spheres under real-time observation in a scanning electron microscope. Poly(methyl methacrylate) spheres with a diameter of 30 lm and four different film thicknesses (270 nm, 150 nm, 100 nm, and 60 nm) were investigated. By multiplying the experimental results with geometrical correction factors obtained using finite element models, the resistivities of the thin films were estimated for the four thicknesses. These were higher than the resistivity of bulk silver.

URLhttp://dx.doi.org/10.1063/1.4959783
DOI10.1063/1.4959783