PCB Electroless Copper
Printed circuit boards integrate multiple layers of thin circuits to meet the needs of modernization. If used regularly, connect the interconnected plated-through holes as this is a simple and effective method. Electroplating is a term that triggers when the task is to deposit a thin layer of conductive material, but in PCBs the conductive metal must be plated onto a non-conductive surface in a confined space ranging from few microns to a millimeter in diameter.
Electroless copper plating is the ideal solution for this task. It is based on a very simple principle that can be easily done by carrying out a series of successive baths with electrochemical and cleaning stages of the target material. This makes it easy to control the thickness of the deposited metal and other deposition parameters.
Electroless copper plating process begins with the application of masks to focus the plating into the specific areas. The conductive adhesive is typically applied to the wall of the borehole in the form of a charged solution containing a metal oxide such as palladium. This process allows the wall to conduct electricity to the level that conventional plating can happen.
The hole that receives the electroless copper plating is then immersed in many developers and the shower is rinsed to adjust the amount of coating material. Copper plating is the final stage in which the multi-phase copper coating is completed to make the via conductive. Since the solder mask can not cover the vias, additional plating is done with more conductive and less active metal alloys, such as gold and tin, to prevent copper oxidation and improve conductivity. Gerber files specify the size of vias and copper thickness. It takes about 10 to 15 chemical baths and processes to complete electroless copper plating.