Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Black pad defect

I am interested in knowing if anyone has new information abo... - Feb 11, 2003 by

Add this forum to your site! Click to learn more. SMTA

Jodi Roepsch

#23346

Black pad defect | 11 February, 2003

I am interested in knowing if anyone has new information about the black pad defect with ENIG plating. I am interested in it from the viewpoint of risk assessment, testing done on final product to isolate failures,and root cause of the defect. Thanks for your input.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#23349

Black pad defect | 11 February, 2003

What do you mean by "new information"?

On final module testing: * If you have hypercorroded nickel and you detect it during final testing, you'll notice it. * If you have hypercorroded nickel and you don't detect it during final testing, you'll ship it.

In short, if you're depending on final module testing to catch black pad problems, you should bump the level of your product liability insurance.

Root cause of the defect is poor board fabrication process control. * If the nickel plate is electroless, quite often the plating bath contains phosphorous which codeposits with the nickel. The phosphorous content in the nickel plating must be around 8% for the nickel to be solderable. * If the nickel is applied by electroplating, it is possible for Ni(OH)2 to precipitate with the nickel plating. * If the nickel is not properly activated by acid rinsing before the gold plating is applied, it will not solder when the gold is dissolved away into the solder. In effect, the gold-contaminated solder may stick to some clean areas of the nickel. * Another possibility is the codeposition of carbon with the nickel, which is another contamination that could cause solder not to bond.

The most prudent steps you can take are: * Work with suppliers that understand the issue and are willing to take steps to prevent the problem. * Institute proper incoming inspection acceptance procedures. * Qualify an alternate solderability protection for your boards.

reply »

#23352

Black pad defect | 12 February, 2003

Get the January 2003 issue of Circuits Assembly Mag. It has more than you could ever want to know about this topic.

reply »

genny

#23353

Black pad defect | 12 February, 2003

The issue is on the web. The current issue is February, so check for past issues at http://www.circuitsassembly.com/

reply »

MA/NY DDave

#23364

Black pad defect | 12 February, 2003

Hi

And Thanks.

I couldn't find it with the link you gave.

And I don't have my magazine with me.

I love a click that gets me RIGHT THERE

YiEng, DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

MA/NY DDave

#23365

Black pad defect | 12 February, 2003

Hi,

Gee David F is as bad or as good as me on a bad day. Boy can I get mad...

"new information"

Many of these defects have been around so dang long and seem to get recycled as the latest rage and the newest of new information in technical articles.

With lead free, or no lead old issues are coming on back. Tin Whiskers, , ,

I didn't check all he wrote yet I bet David F is close to home plate on the Chemistry concerns.

Hey it happens when you get a tad older in this business.

So

Read the articles and read what David F wrote and be a Continuous Improver in your own shop.

YiEng, DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

genny

#23375

Black pad defect | 13 February, 2003

Did it take you to the magazine website? Just scroll down to where it says magazine on the left side, choose past issues and pick January. I think it was the featured article. Or try this to go right to that article. http://www.circuitsassembly.com/pdf/0301/0301raytheon.pdf

reply »

bernard

#23439

Black pad defect | 20 February, 2003

Hi Jodi,

You helped write the circuit assembly article , so why the question ?

reply »

#23444

Black pad defect | 20 February, 2003

Maybe she wanted everyone to read her article?

reply »

#23751

Black pad defect | 11 March, 2003

SMTA [www.smta.org] New On-line Presentation - March 14 Dealing with the Black Pad Defect in Manufacturing Solectron Vice President of Technology Srinivas Rao And Director of Process Integration Kim Hyland Date: Friday, March 14 Time: 10:30AM - Noon (Pacific US)

reply »

MA/NY DDave

#23764

Black pad defect | 11 March, 2003

Hi David F,

You are GREAT!!

You must have read my mind by posting this notice so our intial responder can tune in if she so wishes.

YiEng, MA/NY DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

Paul.malone@teradyne.com

#23797

Black pad defect | 14 March, 2003

What current desity package would you draw the line for the use of ENIG (imm. IO count/ etc

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

MA/NY DDave

#23800

Black pad defect | 14 March, 2003

Hi

Well maybe someone else has better info yet I don't see this fully associated with density of package. As long as the process gives a good Electroless NI, Immersion AU you should be OK. If it doesn't and the process output is marginal as has been experienced by several companies recently then you will have failures or reliability hits.

YiEng, MA/NY DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

Jodi Roepsch

#23812

Black pad defect | 17 March, 2003

Thanks to everyone who took my question seriously and made an effort to share information on this topic. I have done extensive literature searches on this topic in the past but am still looking for more information regarding how this defect affects reliability. I am still interested in how other companies are screening for this defect and whether or not new testing has been incorporated to qualify their product.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

MA/NY DDave

#23813

Black pad defect | 17 March, 2003

Hi

A GREAT come back!! After a Wait to see "Show and Tell"

To change the topic you launched a little.

Who has or has had, this ENIG problem???

A simple yes or no with some detail.

YiEng, MA/NY DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#23814

Black pad defect | 17 March, 2003

Converting to immersion silver is the best solution to the "black pad problem".

reply »

#23831

Black pad defect | 19 March, 2003

Jodi

What's your thinking on the black pad rework technique proposed in: �A Failure Analysis And Rework Method �� Z. Mei, et al, SMTA International 1999, p407

reply »

Jodi Roepsch

#23839

Black pad defect | 19 March, 2003

From my experience, we have had little success in reworking boards with the black pad condition. In one instance, with several reworks, we were able to get plated through holes with the defect to take solder but the joint reliability was highly questionable. The condition reported in this paper is different than what was present on the boards we have reworked. We have not seen a high carbon content, they did not have the high phosphorus content.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#23845

Black pad defect | 20 March, 2003

Jodi

We too have had little success with the approach described in the referenced paper. What method do you use?

reply »

Jodi Roepsch

#23847

Black pad defect | 20 March, 2003

We have not found a way to rework boards successfully at this time. Boards with severe black pad get scrapped.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

MA/NY DDave

#23857

Black pad defect | 20 March, 2003

Hi Guys,

There are techniques to do rework that involve molecular surgery even when selective, ablation and piles of localized techniques exist yet the cost is far too high and scrapping is mostly a best cost manufacturing alternative. At the cost of boards now days, one would be a fool not to just get the next board.

YiEng, MA/NY DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

Enrique Chairez

#23944

Black pad defect | 27 March, 2003

Hi All,

I have observed this problem with one PCB supplier, the portion of the PCB area affected was cut and observed in SEM (Scanning Electron Microscope) and submitted to an EDX (Energy Disperse X ray analysis), finding Phosphorus levels higher to 10% using 10 K eV. The supplier used a 20 K eV set up, they could not duplicate our readings, they get lower readings.

The PCB says that the best acceleration voltage on the EDS for measuring Phosphorus is 20 K eV.

Is this correct?

Best regards,

Enrique

reply »

MA/NY DDave

#23946

Black pad defect | 27 March, 2003

Hi Enrique,

I don't remember all the energy levels that make the techniques you or your associates are using, effective.

Each energy level yields information that must be understood is the best that I should give. HEY Based on my comment, does this mean I am a politician.

There are potentially some other web sites for you to ask your question and receive far better info, than on this site. Without knowing check out American Laboratory for one. They might have a link to a Discussion Group. Also check on the web on Materials Analysis.

YiEng, MA/NY DDave

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

#23949

Black pad defect | 27 March, 2003

Enrique

It's true that higher energy guns do a better job measuring "light" materials. [Actually, if that was true by itself, you'd expect the fabricator's readings to be higher than yours. But, HEY!!!] Regardless, there's alot more to getting and accurate EDX measurement than the energy level of the gun. It's like Gil Zweig at Glenbrook said about x-ray inspection machines during an SMTnet OnBoard Forum, it depends on the gun, camera, and all the elements. Sometimes, obtaining the best sensitivity for selected elements may involve choosing a specific anode, a number of which are available.

X-ray tubes that have power levels ranging from a few watts to several thousand watts are now available. * Research-grade spectrometers typically use the high-wattage systems. * QC/QA analyzers use very low wattage systems (less than 500 watts).

Listen, rather than getting into a contest over whose gun is BIGGER, why not send your sample for arbitation to: * Independent laboratory * Nearby university * Alternate supplier [that would really PO this supplier and certainly could be argued to be unethical, but it's fun to think about, when they're playing with you]

reply »

scottf

#24009

Black pad defect | 2 April, 2003

Make the move to Silver Immersion, no nickel to mess with!

reply »

Plasma Prior to Conformal Coating

Heller Industries Mark 5获得了 2015年中国SMT远见奖 - 回焊炉领域