IPC 4556A ✓ Most Recent

This performance specification sets the requirements for the use of Electroless Nickel/Electroless Palladium/ Immersion Gold (ENEPIG) as a surface finish for printed boards. This performance specification defines ENEPIG deposit thicknesses for applications including soldering, wire bonding and as a contact finish. It is intended for use by chemical suppliers, printed board manufacturers, electronics manufacturing services (EMS) and original equipment manufacturers (OEM). This standard may be used to specify acceptance criteria to meet performance requirements in addition to those found in the IPC-6010 series (IPC-6012, IPC-6013 and IPC-6018) of standards. The ENEPIG deposit specified by using this document will meet the highest coating durability rating as specified in the J-STD-003 printed board solderability specification.

This specification is based on three critical factors:
1) The ENEPIG plating process is in control producing a normal distribution for nickel, palladium and gold deposit thickness.
2) That the tool used to measure deposit thickness, and therefore control the process, is accurate and reproducible for the thickness ranges specified.
3) That the ENEPIG plating process results in uniform deposit characteristics.

If any of these three critical factors are not met, then the deposit produced will not meet the performance criteria defined herein.