In , the IPC released IPC-4556 Revision A , representing a significant update to the standard. This new revision:
"All ENIG is the same; I don't need the spec." Fact: Non-compliant ENIG is a leading cause of intermittent field failures due to black pad syndrome. The spec directly prevents this.
The IPC-4556 PDF covers a wide range of topics related to soldering printed boards, including: ipc4556 pdf
This layer stack makes ENEPIG a "universal finish." It is compatible with soldering and wire bonding for gold, aluminum, and copper, making it ideal for advanced applications like High-Density Interconnect (HDI), fine-pitch components, and high-frequency electronics. The standard is intended for use by chemical suppliers, PCB manufacturers, electronics manufacturing services (EMS) providers, and original equipment manufacturers (OEMs).
ENEPIG is a multifunctional, three-layer surface finish plated over a copper base metal. Its primary components are: In , the IPC released IPC-4556 Revision A
Found in pacemakers, imaging hardware, and diagnostic tools requiring long-term reliability.
IPC-4556 defines exact thickness ranges for each of the three metallic layers. Adhering to these ranges prevents common PCB defects like "black pad" syndrome and brittle solder joints. Layer Thickness Requirements The IPC-4556 PDF covers a wide range of
ENEPIG earned the nickname "universal finish" because it excels where other finishes require compromise. Prevention of Black Pad Syndrome
Provides a stable barrier against copper diffusion and offers wear resistance for contact applications. Electroless Palladium (EP):
Must meet IPC-J-STD-003 requirements to ensure uniform solder joints.
Meets Category 3 solderability requirements, ensuring a shelf life of at least 12 months under proper storage.