Doug Surely, if you had ants exuding acid that would be 'antacid' and therefore neutral, wouldn't it? Or am I just a little mixed up here?:-) Regards Mike _____ From: [log in to unmask] [mailto:[log in to unmask]] Sent: Wednesday, September 12, 2012 12:38 PM To: [log in to unmask] Cc: [log in to unmask] Subject: Re: [TN] Source of IC Contamination Species Speaking of formates, perhaps Rich has ants running around on his assemblies. We had an assembly come into a service center from Brazil crawling with ants which we found exude high amounts of formic acid. Doug Pauls From: Mike Fenner <[log in to unmask]> To: <[log in to unmask]> Date: 09/11/2012 02:34 PM Subject: Re: [TN] Source of IC Contamination Species Sent by: TechNet <[log in to unmask]> _____ 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]> 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] ______________________________________________________________________