choice of trace width in PCB design
Printed circuit boards (PCBs) require solder masks to protect copper from corrosion, oxidation and other environmental hazards that could shorten their lifespan. Solder masks also help make it easier to inspect the conductive aspects of a PCB and prevent problems like solder bridges during assembly. Creating these features is an essential step in the fabrication of a PCB, and the process itself requires considerable skill and precision to ensure optimal results.
Solder masks are typically applied as a thin, photoresist-like material over a pcb in the form of either a film or a liquid that hardens after exposure to heat. This process is usually performed using lithography, which requires a finely tuned machine to accurately define openings for pads and vias. The thickness of the solder mask is a crucial factor that impacts a circuit board’s quality and manufacturability.
The most common color for a solder mask is green, although it can also be red, white, or black. These additional options allow designers to fulfill specific requirements, such as marking prototypes to distinguish them from mass-produced products or matching the color of a final enclosure. The choice of a particular color also influences the processing and imaging parameters used to image the mask layer on a PCB.
What factors influence the choice of trace width in PCB design
For example, a white or coloured solder mask tends to be less translucent than a green one and can therefore require different exposure times and light energy during imaging, affecting the maximum resolution. Additionally, a red or coloured mask can be more sensitive to temperature and humidity, influencing the drying time and colour stability.
A good solder mask is also important in ensuring that soldered connections are as efficient as possible. The thickness of a solder mask must be sufficient to cover the copper layers beneath it without exposing any excess tin, which can interfere with proper conductivity. This is why the size and shape of a solder mask opening needs to be carefully defined by a PCB designer, so that it matches the dimensions of a pad or hole in the PCB footprint.
The solder mask must also be sufficiently thick to provide insulation and resistance against high temperatures, humidity, and corrosion. For this reason, most solder mask materials are a type of polymer that provides excellent thermal and humidity resistance. Moreover, these polymer materials can be applied through pattern printing and screen-printing techniques. In addition, they can be supplied in a range of different colors to suit customer requirements and aid the inspection procedure.
NEXTPCB offers green, red, blue, black, white, clear and other custom colors of solder mask for our customers to choose from. Each color has its own advantages and benefits, but the most important thing is that the selected color of the solder mask will be compatible with the other components of a circuit board.