Ipc4556 Pdf //free\\

Typically 0.03 μm to 0.10 μm (1.2 μin to 4 μin). 2. Performance Requirements

IPC-4556 defines the industry standard for Electroless Nickel/Electroless Palladium/Immersion Gold (ENEPIG) plating, providing requirements for thickness ranges to ensure optimal shelf life and wire bondability on PCBs. The specification establishes specific ranges for nickel, palladium, and gold layers to mitigate corrosion while supporting lead-free solder assembly. For detailed technical specifications, review the paper from Uyemura . Conforming to IPC-4556 with XRF | ENEPIG Surface Finish

Tape tests verify that the plating layers adhere firmly to the copper substrate without peeling. ipc4556 pdf

ENEPIG is a plated over copper base metal. From bottom to top, the layers consist of electroless nickel, electroless palladium, and immersion gold. This combination creates a multifunctional surface that supports soldering, wire bonding, and contact applications all on a single pad—a capability that distinguishes ENEPIG from simpler finishes like ENIG (electroless nickel / immersion gold).

+-------------------------------------------------------+ | Immersion Gold (Au) | 0.03 – 0.09 µm | +-------------------------------------------------------+ | Electroless Palladium (Pd)| 0.05 – 0.15 µm | +-------------------------------------------------------+ | Electroless Nickel (Ni) | 3.0 – 6.0 µm | +-------------------------------------------------------+ | Copper Base (Cu) | PCB Layer | +-------------------------------------------------------+ 1. Electroless Nickel (Ni) 3.0 to 6.0 µm (118 to 236 µin). Typically 0

Evaluation of the use of ENEPIG in small solder joints - ResearchGate

The IPC 4556 PDF covers the following topics: ENEPIG is a plated over copper base metal

Excellent wetting for SAC305 and other lead-free solders.

The palladium layer acts as a barrier that prevents the aggressive immersion gold process from corroding the underlying nickel, a common failure point in standard ENIG finishes.