ENIG Per IPC-4552

Electroless Nickel Thickness The electroless nickel thickness shall be 3 µm to 6 µm [118 µin to 236 µin] as measured on a pad size of 1.5 mm x 1.5 mm [0.060 in x 0.060 in] or equivalent area.

Immersion Gold Thickness

ENIG General Applications The minimum immersion gold thickness shall be 0.05 µm [2.0 µin] at -4 sigma (standard deviation) from the process mean as measured on a pad size of 1.5 mm x 1.5 mm [0.060 in x 0.060 in] or equivalent area; the typical range is 0.075 µm to 0.125 µm [2.96 µin to 4.93 µin]. Higher gold thickness would normally require extended solution dwell time and/or increased solution temperature. This can increase the risk of compromising the integrity of the nickel undercoat due to excessive corrosion. Setup and measurement methodologies are crucial for accuracy.

ENIG - Soldering Applications Only The minimum immersion gold deposit thickness shall be 0.04 µm (1.6 µin) at -4 sigma from the process mean as measured on a pad size of 1.5 mm x 1.5 mm [0.060 in x 0.060 in] or equivalent area.

The following four provisions shall be met before the ENIG for soldering applications-only is allowed to be implemented.

  • The parts shall be used within six months of date of manufacture.
  • Immersion gold plating thickness process capability shall be demonstrated.
  • Demonstrated measurement capability - A Gauge Repeatability and Reproducibility (GR&R) test shall be run showing acceptable values for the plating thickness ranges in this specification.
  • The deposit shall pass J-STD-003 solderability testing with the appropriate stressing condition of 8 hours at 72°C +/- 5°C [162°F +/- 9°F] and 85% +/- 3% R.H.