Thick copper is often used to prevent corrosion and act as a final surface finish. The specification requires porosity testing to ensure no pinholes expose the underlying substrate.
Destructive testing used during process validation to visually inspect the intermetallic layer under an electron microscope. How to Access the Full Document
Typically 100–150 µin (approx. 3–6 µm). It serves as the primary barrier against copper diffusion. ipc4556 pdf
IPC-4556 is a performance specification developed by the IPC (Association Connecting Electronics Industries). It sets the requirements for the deposition thicknesses of electroless nickel, electroless palladium, and immersion gold.
The current active revision is (officially released in 2013, reaffirmed in 2019). If your search for "ipc4556 pdf" returns a document dated before 2013, it is the original (now obsolete) version. Key changes in Rev A include: Thick copper is often used to prevent corrosion
Appendices 4 and 9 of IPC‑4556 provide specific guidance and considerations for using XRF to measure ENEPIG, making it an essential reference for quality control engineers.
is a critical performance specification that governs the use of How to Access the Full Document Typically 100–150
Protects the underlying palladium from oxidation, ensuring long-term solderability and clean contact surfaces. Key Benefits of Following IPC-4556
A major advantage of following IPC-4556 is that it ensures the surface is compatible with diverse attachment technologies:
If you manage to access the official document (or a reference guide based on it), here are the critical sections you should focus on: