We all know that there are many procedures for making HDI PCB from the planned feeding to the final step. One of the processes is called browning. Some people may ask what is the role of browning?
In the HDI PCB process, browning and blackening are to increase the bonding force between the original board and PP. If the browning is not good, it will cause PCB oxidation surface delamination, unclean etching of the inner layer, infiltration and other problems.
The role of browning has the following three aspects:
1. Remove grease and debris on the surface to ensure the cleanliness of the board surface.
2. After browning, make the copper surface of the substrate have a layer of uniform fluff, thereby increasing the bonding force of the substrate and PP, and avoiding problems such as delamination and explosion.
3. After browning, it must be pressed together within a certain period of time to prevent the browning layer from absorbing water to cause the board to burst.
