HASL is an acronym that stands for Hot Air Solder Leveling, a type of finish for printed circuit boards (PCB).

Description

The PCB is typically dipped into a bath of molten solder such that all exposed copper surfaces are covered by solder. Excess solder is removed by scraping the PCB with hot air knives.

Advantages of HASL

• Excellent wetting during component soldering

Disadvantages of HASL

• Low planarity makes this surface finish unsuitable for use with fine pitch components
• High thermal stress during process may introduce defects to PCB