Bare copper circuits on ultra-thin copper foil clad laminates

Combined usage of two recent developments — 5 microns (1/8 oz.) copper foil and of hot gas leveling technique for solder application — opens a new, unique way of manufacturing thru-hole plated PC boards with substantial cost savings. These cost savings are realized as a result of elimination of processes and problems created by or connected in some way with solder plating operations. The new, cost saving sacrificial copper technique is extremely simple to adopt and utilize in PC manufacturing and with advantage can be used on a full scale of pattern densities — from ordinary boards to extremely fine line circuits.