Electroless copper deposition process of rigid PCB
Why should we chemical deposit copper on hole wall
It’s a common sense that all PCB thickness must be electroplated.
If you have know the stack up of multilayer PCB material, different layer cannot connect.
The walls of the holes are non-conductive glass cloth and resin.
That’s the reason why we should chemical deposit copper on hole wall.
The first step is plateing copper on hole walls
In this step plated use chemical method plated copper.
Due to the chemical plated operating, the most rigid PCB manufacturers prefer plating a very thin layer of copper on the hole walls.
If you have visited a big rigid PCB factory electroless plated deposition process room, you can see the worker clamps the production panel into the jigs.
All panels will fix into the jigs align in line.
And the panels are carried through a series of chemical and rinsing baths by the overhead crane.
Those operation steps are fully computer controlled.
Now there was more and more multilayer rigid PCB board, to create more small smart device.
Do you almost all PCBs with 2 or more copper layers use plated through hole to connect the conductors between the layers.
Even in flexible option connect board, flex PCB also plated copper on the hole walls.
The performance requirement related to the thickness of the plated copper on the hole walls.
The copper thickness of electroless plate deposition process
Before discussing the copper thickness of electroless plate deposition, Emma wants to clear that different products need differ numbered.
Even in some electronic product design, different requirements also use differ copper thickness.
So all we here discuss are from our 4MCPCB experience.
For most normal products, a good connection needs about 20 microns of copper on the hole walls.