Technology developments for terpene cleaning of electronic assemblies

Following extensive process testing and machine development, a spray-cleaning facility utilizing the semiaqueous terpene hydrocarbon Bioact EC-7 was installed at AT&T´s Merrimack Valley manufacturing location in North Andover, MA. This facility, which represents a viable alternative to chlorofluorocarbon cleaning, is used to remove rosin-based-solder paste residues after reflow soldering of surface-mount devices to printed circuit (PC) board assemblies. The authors describe technology developments and operating experience gained during the implementation of semiaqueous terpene hydrocarbon cleaning. The EC-7 spray development/production machine will be used for further technology improvements in semiaqueous cleaning. The provisions incorporated in this machine, including the nitrogen inerting system, will enable the machine to handle almost any semiaqueous or aqueous material that may be developed