Also, consider the fact that component marking is done with inks or etchants that may contain formic acid and/or acetates and derivatives. These may show up under chemical analysis.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
Sent: Tuesday, September 11, 2012 2:32 PM
To: [log in to unmask]
Subject: Re: [TN] Source of IC Contamination Species

I think you have the answer from other posters, so for information to complete the picture:
Some fluxless die attach in high power devices is done using formic acid.
The acid is injected into the (inert) furnace atmosphere at the beginning of the reflow cycle. Formic is used because it breaks down completely at (from
memory) around 110C to H20 and CO2.  
This being the case formates are unlikely to be present after reflow, making the probability high that they are being introduced later or generated elsewhere as postulated.


Regards


Mike Fenner

Bonding Services & Products
M: +44 [0] 7810 526 317
T: +44 [0] 1865 522 663
E: [log in to unmask]

 


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
Sent: Tuesday, September 11, 2012 5:10 PM
To: [log in to unmask]
Subject: [TN] Source of IC Contamination Species

Occasionally, IC analyses are reported to have elevated levels of acetates
and formates.   Is it the general consensus that source of these
contamination is assumed to be the decomposition of larger molecular weight weak organic acids found in soldering fluxes?  I can't imagine that any manufacturer would actually be placing acetic or formic acids directly into a flux formulation. These are much too volatile and aggressive. 

Thoughts?

Rich  Kraszewski
Senior Process Engineer
PLEXUS 
 


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________



______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________