Reverse Treated Foil (RTF). Reverse treated foils involve the treatment of the smooth side of electrodeposited copper. Treatment layers are thin coatings that improve adhesion of the base foil to dielectrics and add corrosion resistance which makes the shiny side rougher than it was before. During the process of making printed circuit board (PCB) panels, the treated side of copper is laminated to the dielectric material. The fact that the treated drum side is rougher than the other side constitutes a greater adhesion to the dielectric. That is the major advantage over the standard ED copper. The matte side doesn’t need any mechanical or chemical treatment before applying photoresist. It is already rough enough for good laminate resist adhesion.
