ENIG vs HASL
ENIG and HASL are two of the most common PCB surface finishes. HASL (Hot Air Solder Levelling) is cheaper and well-suited to through-hole work; ENIG (Electroless Nickel Immersion Gold) is flatter, finer-pitch capable, and lead-free by default — at a higher cost.
What it is
A surface finish protects exposed copper pads from oxidation and provides a solderable surface for component attachment. HASL and ENIG are the two most widely used finishes for general-purpose PCBs.
HASL applies molten solder to the board, then uses hot air knives to blow off excess and level the surface. The result is a tin-lead or lead-free alloy coating, typically 1-25 µm thick. It is the lowest-cost finish in widespread use and provides excellent solderability for through-hole and larger SMT components.
ENIG plates the copper pads with a thin layer of nickel (typically 3-6 µm) followed by an even thinner layer of gold (0.05-0.15 µm). The gold protects the nickel from oxidation and provides a long-shelf-life solderable surface. ENIG is naturally flat, making it the preferred choice for fine-pitch BGAs, QFNs, and press-fit connectors. ENIG is lead-free by default and meets RoHS without further specification. ENIG thickness requirements are defined in IPC-4552B; HASL does not have a dedicated IPC specification and is covered under the general fabrication standard IPC-6012.
When it matters
The choice affects cost, assembly compatibility, and shelf life. HASL costs less but is uneven, ruling it out for fine-pitch components below roughly 0.5 mm pitch. The lead-free variant of HASL has a higher process temperature, which can stress thinner boards. ENIG is flatter and longer-lasting in storage but more expensive and carries a small risk of "black pad" — a brittle nickel layer failure that can cause solder joint cracking. For most prototype and mid-volume work with mixed component sizes, ENIG is the safer default.
Comparison
Cost difference varies with board size, volume, and supplier. The 20-50% range above is indicative.
At Nordic PCB
Both finishes are standard options across our certified suppliers. If you're unsure which to specify, request a quote with both and we'll return the cost delta for your specific board — it's often smaller than expected. For fine-pitch designs, our DFM review will flag if HASL is incompatible with your component footprints.
Related terms
- Surface finish
A surface finish is the protective coating applied to the exposed copper pads on a PCB to prevent oxidation and provide a solderable surface for component attachment. The choice affects cost, assembly compatibility, shelf life, and reliability.
- OSP
OSP (Organic Solderability Preservative) is a water-based organic coating applied directly to exposed copper pads as a low-cost surface finish. It is flat, RoHS-compliant, and ideal for fine-pitch components, but has a short shelf life of 3-6 months and is sensitive to handling.
- Immersion silver
Immersion silver is a thin silver coating (typically 0.1-0.4 µm) chemically deposited on exposed copper pads as a flat, lead-free, RoHS-compliant surface finish. It supports fine-pitch components and multiple reflow cycles but is prone to tarnishing if mishandled and requires careful storage.
- DFM
DFM (Design for Manufacturability) is a structured review of your PCB design against a fabricator's process limits — trace widths, drill sizes, annular rings, solder mask clearances, and stack-up choices — to catch issues before tooling starts. A good DFM review prevents rework, scrap, and missed delivery dates.
- RoHS compliance
RoHS compliance means the PCB and all its components meet the EU's Restriction of Hazardous Substances Directive (2011/65/EU), which limits 10 specified substances including lead, mercury, cadmium, and four phthalates. RoHS compliance is mandatory for electronic equipment placed on the EU market.