Illinois-based PCB fabricator, American Standard Circuits, is now offering in-house ENEPIG surface finish. ENEPIG is the solution to multiple surface finish requirements within one multi metal plating operation.
Utilizing nickel as the traditional barrier layer, the Electroless Palladium creates a buffer between the nickel and the gold. This prevents the interaction of the corrosion of the nickel to allow the ion exchange necessary for the Immersion gold. In a traditional ENIG process the nickel is corroded in order to exchange the nickel surface for the immersion gold reaction (reduction). This can lead to intergranular corrosion of the nickel, particularly where the phosphorous and the nickel meet within the co-deposition of nickel and phosphorous (6-9%).
Using Electroless Palladium, the gold is deposited in a partial immersion process (corrosion) which becomes autocatalytic after the initiation of plating of the gold. This removes any corrosion of the nickel and the subsequent risk of Black Pad. In addition to the obvious risk mitigation, it also provides a highly solderable and wire bondable surface without the use of multiple plated thicknesses of electrolytic soft gold. Typically, a thinner gold for solderability (<10µ”) and a thicker deposit for wire bondability (>50µ”).
The ENEPIG process provides the best of both worlds in a single process sequence as well as complete encapsulation of all copper features.
Educational titles from American Standard Circuits:
- The Printed Circuit Designer’s Guide to…?Fundamentals of RF/Microwave PCBs
- The Printed Circuit Designer’s Guide to… Flex and Rigid-Flex Fundamentals
- The Companion Guide to Flex and Rigid-Flex Fundamentals
- The Printed Circuit Designer’s Guide to… Thermal Management: A Fabricator's Perspective
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Visit I-007eBooks.com?to download these and other free titles.