HASL, hot air solder leveling, coats exposed copper by dipping the panel in molten solder and blasting it with hot-air knives to level the coating and clear the holes. It is cheap, tough, very solderable and has a long shelf life, but leaves domed, uneven pads that make fine-pitch and BGA placement harder, and it gives the board a thermal shock. Lead-free HASL uses tin-copper or tin-silver-copper alloys at higher temperatures.
It's a through-hole power board with 1206 parts, plain lead-free HASL is fine, save the money.
Also heard as
- hot air solder leveling
- hot air levelling
- HAL
- solder leveling
Related terms
Surface finish
Final coating on exposed copper pads that stops them oxidising and decides how well they solder.
ENIG
Electroless nickel immersion gold: flat surface finish of nickel topped with a very thin layer of gold.
Wave soldering
Soldering through-hole parts by passing the board over a standing wave of molten solder.