What is solder mask?

Solder mask, also known as solder resist or solder stop, is a thin layer of polymer material applied to the printed circuit board (PCB) to protect the copper traces from oxidation, contamination, and shorting during the soldering process.

Solder mask is typically a green color, but can also be found in other colors such as red, blue, black, or white. It is applied to the PCB using a silk-screening process or a photoimageable process, where the mask is exposed to ultraviolet light through a film mask and then developed to remove the unwanted mask material.

The main purpose of solder mask is to prevent solder bridges or short circuits between adjacent solder pads during the soldering process. It also helps to improve the overall appearance of the PCB and provides protection against environmental factors such as moisture and dust.

Solder mask is a crucial component in the manufacturing process of PCBs and is a standard feature in most electronic components and devices.