{{Short description|Finish used on printed circuit boards}} {{More sources needed|date=November 2012}} {{redirect|HASL}} '''HASL''' or '''HAL''' (for '''hot air (solder) leveling''') is a type of finish used on printed circuit boards (PCBs).
The PCB is typically dipped into a bath of molten solder so that all exposed copper surfaces are covered by solder. Excess solder is removed by passing the PCB between hot air knives.<ref>{{Cite book |last=Salleh |first=Mohd Arif Anuar Mohd |title=Recent Progress in Lead-Free Solder Technology: Materials Development, Processing and Performances |date=2022 |publisher=Springer International Publishing AG |others=Mohd Sharizal Abdul Aziz, Azman Jalar, Mohd Izrul Izwan Ramli |isbn=978-3-030-93441-5 |series=Topics in Mining, Metallurgy and Materials Engineering Ser |location=Cham}}</ref>
HASL can be applied with or without lead (Pb), but only lead-free HASL is RoHS compliant.
== Advantages of HASL == * Excellent wetting during component soldering. * Avoids copper corrosion.
== Disadvantages of HASL == * Low planarity on vertical levelers may make this surface finish unsuitable for use with fine pitch components. Improved planarity can be achieved using a horizontal leveler. * High thermal stress during the process may introduce defects into PCB.
== See also == * Electroless nickel immersion gold (ENIG) * Immersion silver (IAg) * Organic solderability preservative (OSP) * Reflow soldering * Wave soldering
== References == {{Reflist}}
Category:Printed circuit board manufacturing Category:Soldering