Solder Mask
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The solder mask, also known as solder resist, or solder stopp mask, is used to define and protect soldering areas by preventing solder from reaching undesired areas.
Material
It typically consists of a thin, non-conductive material such as epoxy resin or polyimide. It is applied over the printed circuit board (PCB), and then the pads and traces where solder is intended to be applied are exposed. The solder mask forms a barrier between the exposed areas and adjacent areas where soldering is not intended.
Function
The main function of the solder mask is to prevent short circuits between solder joints. During the soldering process, the solder melts and flows onto the exposed pads and traces. The solder mask prevents the solder from flowing beyond the defined boundaries and forming unintended connections between adjacent traces or pads. This enhances the reliability and quality of the PCB.
The solder mask also offers additional benefits. It protects the copper surfaces of the PCB from oxidation and corrosion during storage and use. Additionally, it provides some protection against contamination and moisture.
Manufacturing & Color
The solder mask is typically applied to the PCB through silk-screen printing or Liquid Photoimageable coating (LPI coating). It can be manufactured in various colors, with green being the most commonly used color. Other colors such as red, blue, or white are also used to meet specific requirements or design preferences.
