Technetter,

Recently, we're asked to change our boards finishing from immersion gold to
HASL due to to some claims that HASL finishing is better in sense of joint
adhesion for the BGA & QFP component. How true is that?

To my knowledge, HASL boards is troublesome too as it has surface
coplanarity issue.

Is it right to say that the coplanarity of the solder is measured using the
solder thickness measurement from 250 microinch to 750 microinch.

Regards,

JACOB PAO KING HING
Supplier Quality Engineer,