Written by: Denton Vacuum, LLC
Summary: Applying copper to a circuit board is a delicate and precise process.
When creating a semiconductor, engineers had a problem to solve. They needed to be able to transfer wattages across the board to various areas, like a processor or electrical component, which required very precise pathways. Early circuit boards were not pretty. They had globs of soldering stuck to them, and they looked like something an amateur would make. Today’s boards are expected to handle more complex tasks, and so a complex technique like thin film vacuum coating is required to lay the copper exactly as needed.
Break the Metal Down
The first step in applying metal to a circuit board is to boil and break the metal down into a gaseous form. The trouble is that in doing so, you risk damaging whatever can’t withstand the boiling point. If you wanted to metalize a screw, for instance, the plastic would evaporate well before the metal would.
The solution is to utilize vacuum deposition systems for temperature control at precise intervals. In a vacuum, particles can float freely and cool as they come to settle on the substrate. A mixture of aluminum and copper is quite common, and it helps to reduce the effects of electromigration across the board as power is transferred.
A PVD system can lay the aluminum/copper mixture only after the layout of the board has been determined. For that, engineers utilize a form of thermal printing to mark the device with an ink that is not visible to the human eye. This tells the advanced machinery where to place metal or how to coat an object.