Advanced packaging and electronic assembly cleaning fluid innovation

Abstract

The miniaturization of modern electronics decreases conductor widths, which can create higher risk to insulation failure. As distances between conductors reduce, electronic hardware is more vulnerable to insulation failure, higher voltage gradients and easier to form a corrosion cell. Interconductor spacing influences the migration rate and is inversely related with conductor width. Acceleration factors create multiple stresses due to activation energy, temperature, humidity and voltage. Removal of process residues is needed to reduce electrochemical migration. Cleaning electronic hardware is well known. The challenges with cleaning highly dense hardware are many. Low standoff gaps prevent flux outgassing and can underfill the bottom termination with active flux residue. Mixed metals can react with alkaline cleaning agents, which can result in galvanic corrosion. The time and energy needed to reach the residue and remove contamination under the component requires high pressure spray impingement and increased wash time. The purpose of this research is to present aqueous cleaning technology innovations to address the challenges of cleaning highly dense electronic hardware. Material compatibility on mixed metals, cleaning performance and bath life studies will be presented.