The increasing use of lead-free solder has introduced a new set of process parameters when setting up wave solder equipment for effective soldering. Determining the proper flow characteristics of the solder wave for adequate hole fill is an essential step in achieving a reliable process. A variety of solder waves exist in the industry; each with advantages and disadvantages when performing lead-free wave soldering. One way to ensure adequate hole-fill is by increasing contact time at the Chip Wave.

This paper will present recent work done on an innovative way of increasing contact time, hence improving hole fill for relatively challenging board design. This work also examines effect of various process parameters including effect of nitrogen on hole fill. In addition to the experimental work, comparison and discussion of many variations of solder waves including: "A" type waves, laminar waves, dual waves, inerted shrouds, tunnels, and non-inerted waves will be discussed in this paper. Information will be provided on improved utilization of old wave solder equipment and the correct selections of new equipment to optimize lead-free wave soldering.