HAL lead free
HAL (Hot Air Level(l)ing) is the most common surface finish. It is very good for standard SMD. With this surface you are not able to realize a homogeneous thickness because the surface will be made by a tin bath. The tin produces drops at the edges of holes and pads so that the surface could be very thin there. So it is suitable for standard SMD but for fine pitch applications, a chemical surface is preferable.
PROS:
- good shelf life (approx. 12 month)
- good solderability
- good reflow capacity
CONS:
- pads are not planar
- limited usage of fine pitch
