Ipc4556 Pdf May 2026

Excellent wetting for both lead-free (SAC305) and leaded (Sn63Pb37) alloys.

is the primary industry standard defining requirements for Electroless Nickel / Electroless Palladium / Immersion Gold (ENEPIG) plating on printed circuit boards (PCBs). Often called the "universal finish," ENEPIG is unique because it supports multiple assembly processes—including soldering and various types of wire bonding—on a single surface. Core Layer Requirements ipc4556 pdf

High pull strengths for gold, aluminum, and even copper wire bonding. Excellent wetting for both lead-free (SAC305) and leaded

A major advantage of following IPC-4556 is that it ensures the surface is compatible with diverse attachment technologies: Core Layer Requirements High pull strengths for gold,

This critical update added a maximum gold thickness of 0.070 µm. This limit prevents "hyper-corrosion" of the nickel, which can occur if the gold plating process is too aggressive or prolonged.

ENEPIG was developed largely to solve the "black pad" corrosion issues sometimes found in ENIG (Electroless Nickel / Immersion Gold) finishes. The palladium layer acts as a buffer, preventing the immersion gold reaction from attacking the underlying nickel.