In general, only when the PCB boards pass the quality test, there will be then a plenty of soldermask process steps. Solder mask, also known as solder resist, has many functional characteristics. Literally, while soldering, except the soldering pads, other parts of the PCB board should be protected to prevent the solder materials from connecting with soldering bridges, as so to prevent the short circuit problem. That’s to say, the other parts are insulated, which effectively protects the original soldering characteristics of the PCB circuit board.
In addition to protect the other non-soldering parts, solder mask has the functional characteristics of corrosive resistance, moisture resistance and fungus resistance in the long-term usage of PCB as well. And the copper traces are also well protected. Exactly speaking, solder mask can also called “Protection Layer” of PCBs.
What’s more, soldermask also has the following functional characteristics:
For Aesthetics purpose
Excellent mechanical and chemical properties
Various colors for choice to meet all kinds of customer's needs