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February 2014

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Tue, 11 Feb 2014 20:30:31 +0000
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TechNet E-Mail Forum <[log in to unmask]>, Richard Kraszewski <[log in to unmask]>
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No. ENIG. 

Rich Kraszewski
PLEXUS
(920)969-6075


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: Tuesday, February 11, 2014 2:01 PM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

You're welcome.

In thinking about this a little more, the only specification that I have 
seen that touches on calcium is in IPC-5704, the bare board cleanliness 
spec that is based on Delco's Q-7000 bare board specification.  In that 
spec, they list that the combined sodium and potassium content has to be 
less than  2 ug/cm2 for non-OSP boards and 4 ug/cm2 for OSP boards.  It 
lists a maximum for total inorganic at 3.8 and 5.9 respectively for 
non-OSP/OSP boards.  So if you had high calcium, you might go over the 
total inorganic.  But I know that those values were based on Wittmers (et 
al) work where the cations were treated as process indicators. 

That brings up a question Rich, are these OSP boards that show the high 
calcium?

Doug Pauls



From:   "Stadem, Richard D." <[log in to unmask]>
To:     <[log in to unmask]>
Date:   02/11/2014 01:53 PM
Subject:        Re: [TN] Risks Associated with Calcium
Sent by:        TechNet <[log in to unmask]>



Now that is a very useful post. Thanks, Doug!

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: Tuesday, February 11, 2014 1:30 PM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

Awwww, it was much more fun being surreal.

Rich, I cannot recall a single instance where calcium, or even high levels 
of calcium had any impact on reliability.  Calcium, potassium, magnesium 
are all pretty benign.  It is the anions that seem to be the root cause of 
many of the electrochemical failures seen in the industry, so that is 
where all the research has been focused.  Phil Wittmer and some of his 
colleagues at Delco Electronics (now Delphi) published papers years ago 
where they treated cations as process indicators.  If you saw high levels 
of potassium, sodium or ammonium, you likely had problems with the 
cleaning of your solder mask developing and cleaning materials.  The 
residues from those chemicals, manifest as high levels of the cations, 
were causes of problems.  They could also indicate a problem with solder 
mask degree of cure, which I alluded to before.  If an incompletely cured 
solder mask is exposed to other plating solutions or flux, then those 
chemicals may be absorbed into the solder mask and not be found by 
conventional ionic contamination testing.  Long story short, I treat it as 
a process indicator, not as a harmful material.

What I would recommend it to take some of the bare boards for the 
assemblies in question.  If they exhibit high levels of calcium in the 
bare board, before they even touch your processses, then you have a bare 
board issue.  If the calcium is low, then do testing throughout your 
process to find where the calcium jumps up in level.  That is always the 
process that I used at CSL.  I would guess Eric Camden would say the same. 

 Simple sound science.  Track back till you find the course.

Doug Pauls



From:   Richard Kraszewski <[log in to unmask]>
To:     <[log in to unmask]>
Date:   02/11/2014 11:40 AM
Subject:        Re: [TN] Risks Associated with Calcium
Sent by:        TechNet <[log in to unmask]>



OK then....

Thanks for the replies.  Even the ones that turned this into a more 
surreal experience than even I typically expect to have on any given 
workday.

My list of more bland replies (albeit it begrudgingly useful) both on and 
off forum include the following:

#1 CaCl2 from deicing compounds. 
#2 Calcium from factory humidification misters
#3 Talc from powdered gloves
#4 E-glass in the laminate
#5 filler in the solder mask
#6 DI water 

The above list is useful from a source stand point, however am still 
struggling with the effects that could be seen with low levels of Ca (i.e. 

<1-2 ugm/inch). I suspect none if any. 

Studies conducted by the Minzari in Denmark suggests that calcium warrants 
limited concerns as only Sn, Pb, Cu and Ag present sizable ECM risk. 
(IEEE, volume 9, Sept 2009).
 
I have a suspicion that any requirements for low levels of calcium on 
assemblies have been propagated from those used in the semiconductor 
industry. While those may be required in semiconductor world, they may not 
have good applicability in the realm of PCA manufacture. 

Any further thoughts on "RISKS" associated with low levels of calcium?

Rich Kraszewski
PLEXUS


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Tuesday, February 11, 2014 9:15 AM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

Hi Steve,

You hit the nail on the head!!

http://www.youtube.com/watch?v=KX9mBaHtTrs


Steve 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick
Sent: Tuesday, February 11, 2014 7:22 AM
To: [log in to unmask]
Subject: Re: [TN] Risks Associated with Calcium

Doug,

Don't overlook that which is right in front of your co-ops face!

Please remember that a cow's tongue is long enough, and flexible enough to 
reach inside its nostrils and extricate whatever may be resident there.

Certainly, at this time of year there may be significant 'thickening 
agents' and moisture present.

Just thought you would like to know for testing!


Steve Creswick
Sr Associate - Balanced Enterprise Solutions 
http://www.linkedin.com/in/stevencreswick
                         616 834 1883




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