What is the Difference between Multilayer PCB Browning and Black Oxide Removal

Multilayer PCB can realize more connections and functions in a small area. In the multilayer PCB manufacturing process, browning and black oxide removal are common manufacturing technologies, so do you know the difference between these two technologies?

Let's first understand the effects of browning and black oxide removal of multilayer PCB - Roughen the copper surface, increase the bonding area, and increase the surface bonding force.

1. Black Oxide Removal

1) Process: PCB Board In→Cleaning Solder Mask→Water Rinsing→Microetching→Water Rinsing→Black Oxide(First)→Water rinsing→Microetching→Pre-dip→Black Oxide(Second)→Water Rinsing→Baking→PCB Board Out

2) Advantages: The bonding force of the black oxide removal technology is better than that of the browning technology.

3) Disadvantages: The black oxide removal technology will increase the contact area between the resin and the copper surface and strengthen the bonding force. But it also brings a flaw - the pink ring.

4) Solution to the pink ring: Improve the acid resistance of the blackened film or introduce a new technology process.

2. Browning

1) Principle: On the surface of copper, the reaction produces a homogeneous, well-adhesive and roughened organometallic layer structure, usually forming a copper bond.

2) Advantages: For browning, the technology is simple, easy to control, the browning film has good acid resistance, and there will be no problems such as pink ring defects. Therefore, if the technology requirements allow, browning is an economical and affordable choice.

3) Disadvantages: The browning technology does not bond as well as the surface treated by the black oxide removal technology.

HoYoGo is an international, professional and reliable multilayer PCB manufacturer with many years of multilayer PCB production experience. We can realize the production of high-tech, high-quality and difficult performance boards, and ensure that every product delivered to customers is of reliable quality.