The Plating of Holes and the Copper Balance
The plating of holes on a PCB is a critical part of the manufacturing process.
Get it wrong and the interconnections between the layers would fail or a least be unreliable as would the solder-ability of the component leads in these holes.
Our target is to deposit approximately 20-25µm of copper in the plated through holes.
However, the Copper Balance of a PCB greatly influences how evenly the copper is distributed across the whole PCB.
The copper distribution shown below would lead to more copper being deposited in areas with less copper density (red).
Resulting in the holes is this area having thicker copper walls and thus a smaller actual finished hole size.
For more information on how to improve the copper balance please see our Tips & Tricks post on How to achieve a more even copper density.