PCB factories use various surface treatment methods for PCB prototyping, each with unique characteristics. Chemical silver is recommended for lead-free soldering and SMT, while HASL offers complete wetting of the copper surface and is suitable for lead-free soldering and visual inspection. Nickel gold is suitable for lead-free soldering, SMT, and resistance to environmental attacks. Electroplated nickel-gold is widely used for contact switch design, gold wire binding, and electrical testing. Nickel-Palladium-Gold is suitable for bonding gold and aluminum wires, lead-free soldering, and is cheaper compared to ENIG.