The coating shall be non-conductive, allow easy removal of flux residue, and provide sufficient adhesion to components.
Types of PCB surface finishes: 1. Hot Air Solder Leveling (HASL). First, the PCB is heated using a hot air nozzle. During the heating process, the solder melts and spreads evenly over the board. The solder solidifies and adheres properly to the board surface as it cools in the furnace after heating. 2. lead-free HASL solder safely protects the board from corrosion and short circuits. 3. immersion silver protects electronic components from corrosion, oxidation and short circuits thanks to the silver layer. 4. immersion tin. Gives the board a metallic appearance. Used to create a durable and corrosion-resistant protective coating. Facilitates assembly and serves to prevent arcing. 5. ENIG Immersion Gold. A layer of gold is applied over the nickel coating to prevent oxidation and provide a glossy surface. 6. ENEPIG - A combination of electrolytic palladium, electrolytic nickel and immersion gold plating. The combination of the three plating methods provides superior electrical and mechanical performance over traditional plating methods. 7. electrolytic solid gold is a type of electroplating that uses a gold-based alloy to create an extremely durable layer. It is used to protect the board from corrosion and wear.