-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

on this site
current topics
topic 0644

Testing porosity of gold over nickel


Could you suggest some techniques to check for gold porosity over nickel?

We plate electroless Ni and then Au over copper circuitry to produce semiconductor packages. I suspect Au porosity is causing us adhesion problems during subsequent Au wirebonding operations.


Yezdi Dordi
- Fremont, California

There is the well-known nitric acid porosity test, which sounds like exactly what you're looking for. One of our readers can probably give us a spec number for it from memory. Right, folks?
(I hope, I hope).

Ted Mooney, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey


There is surely a more easy test; the so-called Dimethylglyoxim test.

You have to make a solution of:
980 ml Ethanol,
7 g dimethylglyoxim
20 ml De-ionised water
1 g Ammonium chloride

Dissolve the components in this sequence. Stir until all components are dissolved

Use a voltage stabilized rectifier at 1.5 V
Make the test sample the anode; use SS-cathodes at 5 - 10 cm distance
Place the sample 1.5 minutes in this solution and rinse it with clear ethanol.
Pores will be visible as very intense red discolored area's.

Use the normal care while handling all chemicals and equipment

Success and let me hear if you were satisfied with this; as far as I know this is an official DIN-ISO -test method.



Harry van der Zanden
Harry van der Zanden
- Budapest, Hungary



Thanks for the suggestions.

So far I have tried exposing the substrate to fuming Nitric acid (just to the fumes for 2 hrs). The problem with this technique is that it still attacks the underlying substrate material (glass reinforced epoxy resin) and lifts up the narrow traces (2 mils), making further inspection difficult.

I will be trying the dimethylglymoxil test next week once I can come up with a fixture to make the anodic connection to the circuitry.

thanks again for the suggestions.

Yezdi Dordi
- Fremont, California


In which specification is this test mentioned? Thank you for your support.

Jean Ph. Mundorff
-Kirchdorf, Switzerland

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site


Disclaimer: It's not possible to diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2018, Inc., Pine Beach, NJ   -   About   -  Privacy Policy
How Google uses data when you visit this site.