Ipc-4556 Pdf -

is the definitive industry specification for Electroless Nickel/Electroless Palladium/Immersion Gold (ENEPIG) plating on printed circuit boards (PCBs) . Released by the IPC Plating Subcommittee, this standard provides the technical framework for the design, fabrication, and quality assurance of ENEPIG finishes, which are favored for their versatility in soldering and high-reliability wire bonding. Overview of IPC-4556

Acts as a diffusion barrier to prevent copper from migrating to the surface and provides mechanical support for solder joints. ipc-4556 pdf

This intermediate layer is the "secret sauce" of ENEPIG. It prevents the gold bath from corroding the nickel (preventing the "black pad" defect) and enables strong gold, aluminum, or copper wire bonding. This intermediate layer is the "secret sauce" of ENEPIG

The primary goal of IPC-4556 is to maintain a balance between cost, manufacturability, and performance through strict thickness limits. Measurements are typically verified using on a standard test pad. Recommended Thickness (µm) Recommended Thickness (µin) Electroless Nickel 3.0 – 6.0 118.1 – 236.2 Electroless Palladium 0.05 – 0.15 2.0 – 12.0 Immersion Gold 0.030 (min) – 0.070 (max) 1.2 (min) – 2.8 (max) Data sourced from Key Engineering Functions of Each Layer Measurements are typically verified using on a standard