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Nickel-tin plating: Tin blistering at 222 deg C

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Hi,

I have a problem in nickel and tin plating. This plating process is nickel followed by tin plating (matt). After subjecting the assembly to 222 degree C for about 1 minute, we found tin blistering appearing on the top surface. What is the root cause for that? How to solve it? Kindly share.

Thanks.

Francis Leow
- Ang Mo Kio, Singapore

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Hai! Friend,
This is common.After nickel plated substrate should be keep in TIN bath for one minute(Nickel activation). There after you should apply current slightly. Initialy do not give load current.
Please folow this procedure.
ANY WAY GOOD LUCK

P.KARTHIKEYAN
- Bangalore, Karnataka, India

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I actually had this same problem a while back. The material I was running was being continuously plated though. It was nickel followed by matte tin. The material was the taken through an infrared oven, which produced what appeared to be blisters after reflow. After several months of investigation, it was found that the blisters were not really blisters at all, in fact, they were blobs of tin. Solid blobs of tin. It turned out that there was a great deal of organic contamination in the bath, and we also found a higher than normal level of carbon in the deposit. After cutting, and the carbon treating the bath, we found that the problem went away. We also changed our additive package to a low-organic product. Hope this helps.

Michael Berrier
plating shop - Addison, Illinois, USA

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Hi Michael,

Do you have or know related literatures or IPC, JEDEC, etc., documents, that supports this findings, bolb of tins (blisters)?

Thanks,

Rio B Palmes
EMS - Philippines

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January 5, 2012

Q. Hello,

I'm currently facing a strange problem with an interconnector which enable me to link 2 circuits.
This interconnector is firstly soldered through a lead free reflow operation, and then soldered on the second board with a selective wave.
During the reflow soldering operation (lead free ° C peak = 245° C for 45-50s)the interconnectors pins,
1/ change color (from light yellow to grey / violet color)
2/ Tin solder drops appear on the pin.



Then I sometimes have troubles to perform the selective wave, and get some bad soldering or dewetting.

I look in the forum and found something very similar to this in the letter 45934.
Michael Berrier in Nickel-tin plating: Tin blistering at 222 deg C Letter 45934

Can you tell me what kind of organic contamination I must look for?
How to check them (with the chemical bath supplier support if needed)?
On the discoloured interconnector, how can I know that there is organic pollution? (what kind of test can be done on the discoloured pin to show pollution?)?

Gerald LE REUN
Supplier quality engineer - Paris, France