Hot air solder leveling
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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.[1]
HASL can be applied with or without lead (Pb), but only lead-free HASL is RoHS compliant.
Advantages of HASL
[edit]- Excellent wetting during component soldering.
- Avoids copper corrosion.
Disadvantages of HASL
[edit]- 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
[edit]- Electroless Nickel Immersion Gold (ENIG)
- Immersion Silver (IAg)
- Organic Solderability Preservative (OSP)
- Reflow soldering
- Wave soldering
References
[edit]- ^ Salleh, Mohd Arif Anuar Mohd (2022). Recent Progress in Lead-Free Solder Technology: Materials Development, Processing and Performances. Topics in Mining, Metallurgy and Materials Engineering Ser. Mohd Sharizal Abdul Aziz, Azman Jalar, Mohd Izrul Izwan Ramli. Cham: Springer International Publishing AG. ISBN 978-3-030-93441-5.