a plasma based soldering method which uses a hydrogen - nitrogen gas mixture to form a plasma , excited to simultaneously clean and heat solder . only a relatively low vacuum of about 125 pascal is required . no heat sources beside the plasma are used to reflow the solder and no flux is necessary . sensitive components can be shielded from plasma ion bombardment and need not be able to withstand the melt temperature of the solder used . the method is suitable for lead - tin solder and can be used to solder polyetherimide baseplates to teflon - glass printed wiring boards at junctions of gold - plated posts and matching gold - plated hole linings .