Differences between Roll Anneal Copper Foil and Electrolysis Deposition Copper Foil
Roll Anneal Copper Foil (RA copper):
Formation: Roll copper block many times, and then do the annealing treatment with high temperature. The shape of its crystal is lamellar structure.
Advantage: Soft, smooth surface, suitable for flexible PCB and small lines.
Shortage: high cost
Electrolysis Deposition Copper Foil (ED copper):
Formation: Melt copper into dilute sulfuric acid, it becomes bluestone solution.
Through a high electric field, copper attach on the metal drum. With the rolling of metal drum, thin copper foil finally formed.
Advantage: Low cost
Shortage: Unsuitable for small lines; bad bending resistance.
Here is the cross section observation of RA Copper and ED Copper: