Surface Finish

PCB surface finish is a coating applied to the exposed copper areas of a printed circuit board to protect the copper from oxidation and ensure good solderability. The choice of surface finish affects the PCB's performance, cost, and shelf life.

Jichangsheng Technology supports all major surface finishes. Our team can help you select the best surface finish for your application.

Surface Finish Comparison

Surface FinishTypeFlatnessCostShelf Life
HASLLead-free/LeadedPoorLow12 months
ENIGLead-freeExcellentMedium-High12 months
OSPLead-freeExcellentLow3-6 months
Immersion TinLead-freeExcellentMedium6 months
Immersion SilverLead-freeExcellentMedium6-12 months
ENEPIGLead-freeExcellentHigh12 months

HASL (Hot Air Solder Leveling)

Lead-free / Leaded

The most common and cost-effective surface finish. Molten solder is applied to the PCB and then leveled with hot air knives. Lead-free HASL uses SAC alloy (SnAgCu). Suitable for most applications.

Advantages
  • + Low cost
  • + Easy to solder
  • + Long shelf life
  • + Widely available
Limitations
  • Uneven surface
  • Not suitable for fine pitch
  • Thermal shock

ENIG (Electroless Nickel Immersion Gold)

Lead-free

A two-layer metallic coating of nickel and gold. The nickel layer acts as a barrier to copper and provides a hard surface. The gold layer protects the nickel during storage and provides a solderable surface.

Advantages
  • + Flat surface
  • + Good for fine pitch
  • + Long shelf life
  • + RoHS compliant
Limitations
  • Higher cost
  • Black pad risk
  • Not suitable for wire bonding

OSP (Organic Solderability Preservative)

Lead-free

A water-based organic compound that selectively bonds to copper and provides an organometallic layer that protects the copper until soldering. Very flat surface finish.

Advantages
  • + Very flat surface
  • + Low cost
  • + Environmentally friendly
  • + Good for fine pitch
Limitations
  • Short shelf life
  • Sensitive to handling
  • Not suitable for multiple reflow

Immersion Tin

Lead-free

A thin layer of tin deposited directly on the copper surface. Provides a flat, solderable surface. Suitable for press-fit connectors.

Advantages
  • + Flat surface
  • + Good for press-fit
  • + RoHS compliant
  • + Good solderability
Limitations
  • Short shelf life
  • Tin whisker risk
  • Sensitive to handling

Immersion Silver

Lead-free

A thin layer of silver deposited on the copper surface. Provides excellent solderability and a flat surface. Suitable for high-frequency applications.

Advantages
  • + Flat surface
  • + Good solderability
  • + Low cost vs ENIG
  • + Good for RF applications
Limitations
  • Tarnishes quickly
  • Sensitive to handling
  • Short shelf life

ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold)

Lead-free

A three-layer coating of nickel, palladium, and gold. Eliminates the black pad issue associated with ENIG. Suitable for wire bonding and fine pitch applications.

Advantages
  • + No black pad issue
  • + Suitable for wire bonding
  • + Excellent solderability
  • + Long shelf life
Limitations
  • Highest cost
  • Complex process