Drum Side Treated Foil: Advanced Copper Foil Technology for Multilayer Printed Circuit Board Applications

Drum Side Treated Foil is an electrodeposited copper foil with the adhesion promoting treatment applied to the drum, or shiny side, instead of to the more typical matte side. The treated drum side is then laminated to the core prepreg, leaving the matte side exposed. Advantages of this technology, compared with standard copper foil, include: Simplified, non-subtractive pre-cleaning, eliminating the need for microetching, pumice cleaning or mechanical scrubbing; improved resist adhesion for higher innerlayer yield; ultra-low profile for cleaner etching and improved line definition; higher oxide-to-prepreg bond strength for improved board reliability; improved controlled impedance consistency and predictability. A technical description of Drum Side Treated Foil’s inherent advantages, processing recommendations and results of several case studies comparing printed circuit board yields with Drum Side Treated Foil vs standard foil are presented in this paper.