CLEANING OF PRINTED-CIRCUIT BOARD BY OCTA METHYLCYCLOTETRASILOXANE PERFLUOROCARBON/

Studies were made on cleaning solvent systems for printed wiring board s on which pricision parts are mounted by soldering them with flux con sisting of rosin and a polar compound. We anticipated that a mixture o f diethylene glycol monobutyl ether (DGB) and octamethylcyclotetrasilo xane (D4) is a promising solvent system having solubility parameter si milar to those for good solvents of rosin and a high dielectric consta nt for dissolving the polar compound. As the subsequent cleaning proce ss, D4 and perfluorooctane (PFO) were examined as rinsing and vapor-dr ying solvents, respectively. As a result, this cleaning system was fou nd 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.