Each kind of floor end has its own advantages and downsides. There are some engineering methods as the solutions to the problems brought on by cons of surface end. For instance, as for the disadvantage that OSP has lower wetting force, some options can be found corresponding to changing board solderability plating or wave solder alloy, growing prime-aspect preheat and so on.
The key level is that all the potential components have to be considered in order to acquire perfect performance. Surface end selection on PCBs is crucial step for PCB fabrication because it directly influences process yields, rework numbers, field failure price, test capability, scrap fee and price. All the important concerns about assembly must be taken into floor finish selection so as to make sure the prime quality and performance of finish merchandise.
As seen above, HASL can still be a great choice for a floor finish, but enhancements in different surface finishes are making it obsolete. HASL does have a couple of benefits, however compared to others like ENIG, ENEPIG, and different immersion finishes, it is falling short. For instance, ENIG is corrosion resistant, good for aluminum wire bonding, glorious for nice-pitch know-how, excellent solder-capacity, has a fantastic shelf-life, and a lot extra. The features and advantages that made HASL a fantastic selection up to now simply can't examine to the enhancements of the opposite floor finishes.
Confronted with totally different floor finishes with their very own benefits and drawbacks, have you ever suffered from extreme ache when picking up one kind compatible together with your products? All in all, as for the kind of surface finish selection, an optimal sort must be selected and quite a few features could be achieved.
So that one other surface finish course of referred to as ENEPIG was come as much as remedy this problem of 'black pad', but the cost of ENEPIG is comparatively expensive, now it's extra appropriate for HDI boards, CSP or BGA. Up to now, the prevailing floor finishes largely accepted are HASL , OSP , Immersion Tin, Immersion Gold, ENIG and ENEPIG.
A gold layer supplies varied benefits including low contact resistance, high strength, few chances of oxidation, and antifriction. These properties assist meet circuit conductivity requirements, as well as defend nickel, and copper layers from oxidation. It additionally has a bonus over traditional HASL almost about coplanarity, and its solderability. However, this finish does require significant modifications with the kind of flux and variety of warmth cycles used throughout assembly course of.