"Fine-Line Through-Hole Copper Filling in VCP for Next-Generation Packaging"
Authors: Olivier Mann, Ph.D., Henning Hubner, Angelo Ferro; firstname.lastname@example.org.
Abstract: This paper presents the complete through-hole filling for cores using a Cu electroplating process for IC package production, especially for FC-BGA and FC-CSP. There are two main objectives for this application: technological aspects and productivity. When it comes to pattern through-hole filling, the process presented has been designed for vertical continuous plating (VCP) equipment. To meet the technological requirements for next-generation packaging, parameters such as pattern plating with excellent within-unit distribution and inclusion-less filling performance are of utmost importance. From a productivity standpoint, high current densities and reduced plated thickness are the preferred methods. This paper focuses on technological aspects and difficulties of filling through-holes of various dimensions and sizes. Fluctuating drilling tolerances/qualities (protruding glass fibers, laser drilling asymmetry) give indications how to minimize the inclusion rate. The influence of electrolyte agitation, current density, and inorganic and organic concentrations on the filling performance are described and discussed in detail. The resulting new process has shown improved capability to fill though-holes in cores up to 200pm. (SMTA International, September 2017)