During the initial development of the chip on board (COB) fine ball grid array (FBGA) process, repeated reliability failures resulting from delamination between the epoxy molding compound and the solder resist interface created a need to investigate treatments to improve adhesion between these surfaces. One such means for improvement was exposing the solder resist to plasma prior to molding. A study of the effects of plasma treatment on solder resist as it applies to the assembly of COB FBGA packages was performed. In this study, solder resist samples were subjected to direct and downstream plasma treatments at various settings. The treated samples were then examined for chemical and physical changes via X-ray Photoelectron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and contact angle. Changes in the surface during storage were also evaluated.