Hi Terry,
With all due respect I have to disagree. I've been doing that kind of analysis since last Millennium :-) and have to say that using a higher resolution surface analysis technique (WDS and/or SIMS, Auger) in the vast majority (or should I say pretty much in all of them) of cases did not help more than EDS.
Regards,
Vladimir
SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (647) 495-8727
Cell: (416) 899-1882
www.sentec.ca
-----Original Message-----
From: Terrym <[log in to unmask]>
Sender: TechNet <[log in to unmask]>
Date: Sun, 3 Mar 2013 20:11:14
To: <[log in to unmask]>
Reply-To: TechNet E-Mail Forum <[log in to unmask]>, Terrym <[log in to unmask]>
Subject: Re: [TN] corrosion under Solder Mask
We also have been correcting fab processing for years that is the root cause. We find that SEM/EDS analysis doesn't give a good quantitative value to compare the process to. If you need SEM / support let us know.
Terry Munson's iPhone
On Mar 3, 2013, at 4:31 PM, Inge Hernefjord <[log in to unmask]> wrote:
> Vladimir is right, make a SEM investigation to see if it really is
> corrosion and not something else e.g. contaminated water or crystalized
> solvent residues etc. And take some high resolution photos at varying
> magnification.
>
> I've been analyzing such things for years and I could guide you, as well
> as Vladimir, but you'll certainly find assistance at some uni or
> independent lab in your area. I am lazy, so instead of using own words, I
> copied a page from a book, written by a guy in your country. I placed the
> page in Dropbox/Reports../Analysis../Ramakrishnan. You have admission
> already.
>
> Good Luck
>
> Inge
>
>
> On 3 March 2013 00:29, Vladimir Igoshev <[log in to unmask]> wrote:
>
>> It could be zillions of reasons and unless proper FA is done you are
>> NEVER going to figure out what exactly caused the problem.
>> ------Original Message------
>> From: Ramakrishnan Saravanan
>> Sender: TechNet
>> To: [log in to unmask]
>> ReplyTo: TechNet E-Mail Forum
>> ReplyTo: Ramakrishnan Saravanan
>> Subject: [TN] corrosion under Solder Mask
>> Sent: Mar 2, 2013 18:13
>>
>> Dear all,
>>
>> We have received few MLBs from a contract supplier. The board was
>> inspected and accepted for wiring. The assembly is for high reliability
>> applications. We conformal coated, tested,thermal cycled and closed the
>> package. We opened the package for some rework, we found corrosion under
>> solder mask on some tracks.
>>
>> The corrosion is in the form of blisters and localized. Center of the
>> tracks or edge or localized and not covering the entire width of the tracks.
>>
>> What could be the reason for corrosion under solder mask ?. How to
>> diagnosed for root cause analysis ? regards,
>>
>> R.Saravanan
>>
>>
>> Regards,
>>
>> Vladimir
>>
>> SENTEC Testing Laboratory Inc.
>> 11 Canadian Road, Unit 7.
>> Scarborough, ON M1R 5G1
>> Tel: (647) 495-8727
>> Cell: (416) 899-1882
>> www.sentec.ca
>>
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