HOME FAQs BOOKS JOBS: Help Wanted Suggestions      you are here: Hotline/Forum => Letter 1103

---

Copper plating deposits are forming nodules

--

I am a research assistant at the University of Florida and am trying to electroplate copper onto a nickel substrate, from a sulfimate solution of 1.53 M Ni, 0.014 M Cu and 30 grams/liter boric acid, but I am having problems with copper covering the surface on a microscopic scale. The first copper to form always forms in nodules. Is there a problem with copper nucleation on nickel? Is it more difficult for copper to form on nickel than on copper? Is SNAP the answer to our problems?

We are using round 35mm diameter polycrystalline copper substrates. The pH is 3.5~3.8. The sulfimate solution is commercially pure.

Michael Alexander

---

--

I am sorry that I don't understand the question. Are you trying to plate an alloy of copper and nickel onto a copper substrate using a nickel sulfamate solution containing copper ions?

SNAP is sulfamate nickel anti pit, a proprietary wetting agent, I don't think that is the answer at this point. Is the copper in the sulfamate nickel present in the commercially pure product, or have you added some to the bath?

Tom Pullizzi Falls Township, Pennsylvania

---

--

Mike,

I am with Tom. Are you trying to plate sulfamate nickel with copper in it? If so, why. Copper in more than trace amounts causes a dark junk plate in areas of low current density.

If you are really trying to do this, plate initially at a low current density, about 20 amps per sq ft and then gradually raise it up to final volts and amps. If you do not use a minimum of about 1 volt, you will get immersion (nonadherent) copper plating.

If 20 does not work, try 15 and then 10.

James Watts
- Navarre, Florida

---

--

Hi,

I am a grad student at LSU. I'm trying to plate Nickel on a copper substrate using a citrate complexing agent. Ph of 4.9 - 5.

The substrate is a copper plate with a resist of PMMA with holes of the dimension of 200microns width and 500 micron height.

The problem I am facing is trying a method to :

1. insulate the plate so that the insulation can be taken off without too many problems. I have succeeded in insulating it with electrical tape and a coating of resin above that...any better methods?

2. I am presently using a copper oxide film on the copper to ensure better adhesion of the PMMA. Is there a better method?

Amrit.

AMRIT PANDA
LOUISIANA STATE UNIVERSITY

---

What is PMMA? Isn't the resist supposed to be the mask for the nickel? Sorry, I don't understand. Send us a GIF and we will post it here. Tom Pullizzi Falls Township, Pennsylvania -- There are a number of questions about your process and several possible options. I host the chat line on Monday nights. We could chat about what you are doing and some possible solutions. It may bring comments from several of the regulars in the chat room also. Jim James Watts - Navarre, Florida ANSWER or FOLLOW UP POST an unrelated QUESTION HOT Topics