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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.

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.

Ted Mooney, finishing.com   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.

Electroless Plating
by Mallory & Hajdu

totter James Totter, CEF
- Tallahassee, Florida


(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,

Ted Mooney, finishing.com   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, 2009 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

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


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



January 23, 2015 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

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 -^


February 1, 2015

A. Hi Kevin

Research papers do not indicate a fully developed stable process. They are mostly written to support an academic study and there is rarely any expectation that they will see the light of day again. (The same goes for published patents)

In order for an electroless process to work, it must be just marginally stable. Too stable and there is no deposit; too unstable and it "falls apart" To get the balance right and controllable major suppliers have invested large sums and much expertise. They are unlikely to give away the secrets of their success lightly.

Many thousand litres of commercial electroless copper are in use every day. If your interest is purely accademic, I wish you luck with years of fascinating research before you. But if you are looking for a viable production process, I urge you to contact any of the major suppliers. They will not only supply a working process but also teach you how to operate it - and probably at a lower cost than buying the chemicals.

geoff smith
Geoff Smith
Hampshire, England



Electroless copper plating on polymers

March 26, 2015 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I'm trying to plate polymer wafers in copper using an electroless process. I've successfully manages to get the initial plating layer down but it oxidises after a couple of hours and goes yellow and green! Are there any chemical treatments that could be done to prevent the oxidation? Or are there any chemicals I could include in the bath solution?

It's a DIY electroless process in beakers, no commercial bath and my recipe is as follows;
1 g of NaOH in 20 ml water.
1.25 g of CuSO4 in 20 ml water.
2.9 g of HCHO in 20 ml water.
40 ml water.
30 ml extra of NaOH aqueous solution to keep pH above 12.

Any ideas and suggestions would be useful!

Alex Gregory
Student - Loughborough, Leicestershire, England
  ^- Privately contact this inquirer -^


March 30, 2015

A. If you have the time, you could research the formulae in the patent literature and spend tens of thousands of hours perfecting your formulae. Or, if you don't, you could buy a commercially available bath developed by companies like Macdermid Inc. [a finishing.com supporting advertiser], Enthone, Atotech, and many others, who have already done this for you.

tom_rochester
Tom Rochester
Plating Systems & Technologies, Inc.  

Jackson, Michigan, USA



April 11, 2015

A. Hi Alex

If by student, Loughborough you mean Loughborough University, I suggest that you take yourself to the Department of Materials Engineering where you will find Emeritus Professor David Gabe who will give you infinitely more and better advice than even this illustrious website.

geoff smith
Geoff Smith
Hampshire, England

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