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Formulas for Electroless Copper Plating Baths



An ongoing discussion from 2001 through 2015 . . .

(2001)

Q. Can anybody tell me the formula for electroless copper? (I'm plating acid copper after silver application on plastics, but I want to change to palladium & stannous chloride method because is less expensive and fast). Please I appreciate your help. I only need the formula for electroless copper.

Thanks,

Rafael Arencibia
- Caracas, Venezuela


(2001)

A. I would suggest consulting the "Metal Finishing Guidebook and Directory"; it is also available online (digital version of the Metal Finishing Guidebook).

totter James Totter, CEF
- Tallahassee, Florida



(2002)

Q. Can anyone tell me the formulation of electroless copper plating?

Best regards,

MURAT CETIN
- Izmir, Turkey


(2002)

A. Hi, cousin Murat. If possible, could you please preface your question with who you are and why you want to know, so that people will be in a better position to understand & answer the question? To my knowledge virtually all electroless copper used in the U.S.A. is proprietary (trade secret or covered by patent) rather than made to a publicly available formula. If I'm wrong, I hope another reader will correct me.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2002)

Q. Sorry, I'm working with chrome plating on ABS plastics in Turkey. I'm using palladium/electroless nickel system. But it's very expensive. My EN solution contains nickel chloride, trisodium citrate, ammonium chloride, sodium hypophosphite and lead acetate. Can I work with silver nitrate/borane system with this formulation.

Best Regards...

MURAT CETIN, returning
- Izmir, Turkey


(2002)

A. Thanks, Murat. I'm familiar with the use of two-part silvering solutions to metallize things like the masters for vinyl record stampers where outstanding adhesion to the substrate is not required. But I am not personally familiar with using this process in lieu of the palladium chloride approach for a decorative plating-on-plastics application, where excellent adhesion is probably a requirement. But letter number 10887 discusses that prospect in some detail. Good luck.

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

Electroless Copper and Nickel-Phosphorous Plating



(2003)

Q. I'm a student and am looking for information about copper electroless plating. I have found many different baths formulations; for example, some Tartrate or Rochelle Salt based baths include the following chemicals:
Copper sulfate:
metal source Rochelle Salt:
complexant agent Formaldehyde:
reducing agent Sodium hydroxide:
pH control additives:
stabilizers, buffers, etc.

Some of these formulations also include Sodium Carbonate, but I have not found the specific function of this chemical in the bath. What's sodium carbonate added for?
Thanks in advance for any help you can offer me.

Ana Da Camara
- Caracas, Distrito Federal, Venezuela


(2003)

A. Sodium carbonate may act as buffering agent at pH of solution; for example, in alkaline electroless nickel, NH4Cl can buffer the solution. NaCO3 is mixture of weak acid and strong alkali.the pH of it about 10.

Vahid Hosseini
- Tehran, Iran


(2003)

A. I'm not sure what the function of sodium carbonate in a tartrate electroless copper bath is (maybe a buffer?), but I will tell you this: Tartrate baths are used for ease of waste treatment; the tartrate does not chelate as strongly as EDTA or quadrol. In this type of bath the tartrate (Rochelle salt) is the complexing agent, copper sulfate is the metal source, formaldehyde is the reducing agent, and sodium hydroxide is a reactant.

totter James Totter, CEF
- Tallahassee, Florida

Electroless Plating
by Mallory & Hajdu


(2004)

Q. So is the EDTA or quadrol bath, being a better chelating bath, suitable for electro (rather than electroless) plating then?

Don Leaman
photographer - Orrtanna, Pennsylvania, USA


A. Hi Don. To my knowledge there are no commercial quadrol or EDTA-based copper plating baths. I think James' comment implies that we want to avoid those chemicals where possible because they make proper waste treatment and disposal too difficult.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2005)

A. I am a Lab Technician and deal with electroless copper quite often, The formulation of the bath consists of Sodium Hydroxide, Formaldehyde, EDTA, SR, and electroless copper of course ... The levels of these chemicals are maintained using an "s" controller, which performs constant titrations of the components, and is verified by lab analysis every 4 hrs to ensure accuracy; except the electroless copper is measured in millivolts, which are determined by how much light can pass through the solution, when a sample is passed through a UV vis spectrometer. It is replenished by adding a 3-part chemistry "a, r and c".

jason brown
Jason A. Brown
- Athens, Pennsylvania


(2007)

Q. Hi Jason,
I am a student and I'm currently working on a senior design project on electroless copper coating. I am unfamiliar on what you mean by an "s" controller. Could you please elaborate, or maybe provide a link to where I could find more information?

Thank you.

Abby McKain
- Columbus, Ohio


April 12, 2009appended

Q. Anyone tell me the formulation of electroless copper plating?

Best regards,

mojtaba esmailzadeh
student - tabriz, Iran


January 22, 2010

Q. Hi everyone,

I'm trying to do copper electroless. I already know the formulation of the bath (but I don't know what "SR" means in Jason's comment).

Could anybody tell me how to prepare this bath? I can't obtain it, I'm suffering stability problems.

Thanks in advance

Noelia Díaz
- Las Palmas, Spain

----
Ed. note: Noellia, since you say you know the answer to the previously posted question, please take the time to post the answer before asking your own question ... otherwise you can't really can't expect the next reader to not follow your example :-)



April 28, 2012

Q. Hi
I am a lab analyst working with Electroless copper plating for Printed Circuit Board. I know the composition of the electroless copper solution except "SR". Please explain it.

Also I am interested in finding out the exact amount of EDTA in the plating solution. How I can do this? Anyone have a method to analyze the EDTA in Copper electroless copper solution?

Muhammad Rizwan
- Islamabad Pakistan

----
Ed. note: Muhammad, since you claim to know the answer to an open question, please post it before asking your own question ... or you can't really can't expect the next reader to do differently :-)




January 23, 2015appended

Q. I've found several electroless copper formulas in the research papers, but I've failed to reach the same result as shown in papers, and the bath decomposed most of the time.

I don't know where and which step is wrong.

Here is the formula i was using:
copper sulfate (0.03M), EDTA (0.24M), glyoxylic acid (0.2M), 2, 2'-bipyridine (2.5ppm), volume ( 250 ml), pH:13 (adjusted by (KOH). temperature 70 °C

Here are the steps I've done:
1) added EDTA with DI water and added KOH to adjust pH to 13
2) added 2,2'-bipyridine and copper sulfate to the bath and also keep pH to 13
3) heated up the bath to 70 °C, and then added glyoxylic acid and adjusted pH to 13 with KOH.
4) put the brass substrate (with pre-treatment including cleaning/conditioning, micro etching, acid dipping, pre acid dipping, activator, and DI wash in between for all the step)

It should be about 6 µm/hr.
I followed the formula I found in the research paper, but I failed to obtain the same results (decomposition or a few nm).

Can anyone help me out with electroless copper bath?

kevin Lee
- san jose, California, USA
  ^- Privately contact this inquirer -^

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