Abstract
Studies were made on cleaning solvent systems for printed wiring boards on which pricision parts are mounted by soldering them with flux consisting of rosin and a polar compound. We anticipated that a mixture of diethylene glycol monobutyl ether (DGB) and octamethylcyclotetrasiloxane (D4) is a promising solvent system having solubility parameter similar to those for good solvents of rosin and a high dielectric constant for dissolving the polar compound. As the subsequent cleaning process, D4 and perfluorooctane (PFO) were examined as rinsing and vapor-drying solvents, respectively. As a result, this cleaning system was found to be superior to those using water, hydrocarbon or CFC113/ethanol mixture. A comment was also made on ionic residues on the boards based on quantitative analysis.
