Engineering Notes · NT PCB Engineering Team
ENIG vs HASL vs OSP: Which Surface Finish Fits Your Board?
Short answer: choose ENIG for fine-pitch SMD and long shelf life, lead-free HASL for large-pad and through-hole boards on a budget, and OSP for simple, cost-sensitive assemblies that will be soldered within a few months. We run all three finishes in-house, so this comparison comes from daily production, not a datasheet.
Side-by-side comparison
| Criteria | ENIG | HASL | OSP |
|---|---|---|---|
| Flatness for fine-pitch SMD | Excellent | Poor | Good |
| Shelf life | 12+ months | 12+ months | 3–6 months |
| RoHS compliant | Yes | Lead-free HASL only | Yes |
| Relative cost | Highest | Lowest | Low |
| Best for | BGA, fine pitch, medical & automotive | Large pads, through-hole, power boards | Simple SMD, cost-sensitive runs |
When we recommend ENIG
ENIG (electroless nickel immersion gold) gives a perfectly flat, oxidation-resistant surface. For medical devices, automotive controllers and any board with 0.5 mm-pitch components or BGAs, ENIG is our default recommendation. It costs more per panel, but it removes tombstoning and coplanarity rejects at assembly.
When HASL is enough
For UPS boards, power supplies and through-hole-heavy designs, lead-free HASL remains the workhorse: robust, cheap, and easy to rework. Its uneven surface is a non-issue once pad pitches exceed 1 mm.
When OSP makes sense
OSP is a thin organic coating: flat, lead-free and inexpensive, but with a 3–6 month shelf life and sensitivity to handling. For consumer products moving quickly from fabrication to assembly, OSP offers the best cost-to-performance ratio.
Not sure which finish your design needs?
Attach your Gerber files and our engineers will recommend a finish in the quote.
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