The surface finish for PCB

The surface finish for PCB

HASL is an abbreviation of Hot Air Solder Level. The most common used and cheapest way.

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 process may introduce defects into PCB

HASL lead free
If you choose Hasl without lead. We will use the Halogen Free material(RoHs).  

ENIG is an abbreviation of Electroless Nickel/Immersion Gold which is also known as soft gold.
excellent surface planarity (particularly helpful for PCBs with large BGA packages), good oxidation resistance, and usability for untreated contact surfaces such as membrane switches and contact points.

Hard gold is often used for gold finger.Not good at soldering.