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Introduction to the LDF Coatings Nickel Deposition Process

Tin Whiskers
LDF Coatings patented electroless nickel plating process ELIMINATES tin whiskers by depositing a thin layer of nickel onto the tin surfaces of the electronic assembly.

Patent 9295165

Electroless Nickel Plating Eliminates Tin Whiskers

LDF Coatings claims not just mitigation but prevention of tin whisker growth in electronic assemblies.

The difference is significant.

The enabling technology for the LDF Coatings nickel-cap process is electroless plating, which:

Electroless plating is well established for bare board fabrication, and has been used in other industries for over half a century. The LDF process deposits a thin, whisker-impenetrable layer of nickel on all exposed tin and tin-rich surfaces, but not on the insulating surfaces, of a functional electronic assembly. This selective deposition is accomplished by immersing the assembly in a heated tank of electroless plating solution for a few minutes.

While immersing a functional assembly in a plating solution is novel, we show that with proper process control it is not risky. Any assembly that can survive aqueous post-solder cleaning is unharmed by this immersion. Metal surfaces that are not to be coated are masked in the same manner as they are for conformal coating.

Tin Whisker Mitigation is not a Solution

The current industry approach to tin whisker mitigation is conformal coating, which uses a material selected from a variety of polymers (formulated and characterized for a different purpose—namely prevention of dendritic growth on the board surface). For high-reliability systems, there are significant downsides to conformal coating as a tin whisker remedy.

  1. Conformal coating, no matter how well controlled the application process, only mitigates tin whiskers. It does not prevent whisker growth:
    • Some commercially available conformal coatings resist whisker penetration. However, in tests, all are penetrated over time.
    • Due to shadowing, some tin remains uncoated.
    • Due to surface tension, coating along sharp edges of component terminations tends to be quite thin, which accelerates tin whisker penetration.
  2. Conformal coating materials are polymers, so regardless of which is chosen, their properties are not constant but vary with time, temperature, and humidity.
    • No coating material has been characterized for its whisker-penetration resistance over the full range of temperature and humidity that electronic products encounter in the field.
    • Whatever the choice of coating, it deteriorates over the years during which it is expected to protect the assembly.

LDF Coatings Benefits

In contrast, the LDF Coatings process deposits a micron-thin nickel coating over all exposed tin, which results in the following benefits:

Summary

We encourage you to review the information presented here about LDF Coatings electroless nickel cap process and the protection against tin whisker growth that it affords your electronic assemblies. You will see that the process:

If you want to explore how our patented process can eliminate your tin whisker problem, we welcome the opportunity to discuss with you what we regard as the only true remedy available for overcoming the risk of whisker-caused failures in high-reliability electronic assemblies.

Call us at (603) 964-1818 or contact us by e-mail at info@ldfcoatings.com

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