Electro Deposited (ED) Copper. With ED copper, there is a huge diversity of foils regarding surface roughness, treatments, grain structure, etc. As a general statement, ED copper has a vertical grain structure. The standard ED copper typically has a relatively high profile or rough surface as compared to Rolled Annealed (RA) Copper. ED copper tends to lack flexibility and does not promote good signal integrity. Also check another type Rolled Annealed (RA) Copper.
How to Make ED Copper? ED copper foil is the standard copper used in the PCB lamination industry. ED foil is deposited from a copper solution, at a specific DC voltage, onto a moving polished titanium drum which forms the cathode. The foil is subsequently stripped from the drum. The grain construction formed by this process will from the dendritic “tooth” of the copper on the “bath side” of the copper. The drum side takes on the smooth texture of the polished drum surface onto which it is plated.