Another under fill used is Floropel. Super thin and a little pricey. Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. Sent: Monday, March 27, 2006 1:40 PM To: [log in to unmask] Subject: Re: [TN] Conformal coating and BGA To answer further, no conformal coating should ever be applied underneath a BGA. Some can absorb moisture and swell up, cracking the solder joints. Do not attempt to use conformal coat as an underfill. Also, I would not coat the tops of BGAs either, as some (most notably the metal-top types) have internal or external heatspreaders that will be insulated due to the conformal coating, causing premature component failures. If the danger of shorting is present due to moisture condensation or other moisture or chemical atmosphere hazards are present, use an appropriate underfill epoxy formulated for that purpose. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Macko, Joe @ IEC Sent: Monday, March 27, 2006 11:37 AM To: [log in to unmask] Subject: Re: [TN] Conformal coating and BGA Gil, Hello. I have not heard of any restriction or problems applying c/c to the tops of BGAs however, this does not coat the solder joints (SJs) located under the BGA package, which is required by IPC-A-610. So, c/c BGAs does not apply c/c to the actual SJs located under the package, which violates IPC-A-610 acceptability requirements. We have used various wickable underfills to seal SJs located under BGA packages. joe -----Original Message----- From: Zilber Gil [mailto:[log in to unmask]] Sent: Monday, March 27, 2006 8:17 AM To: [log in to unmask] Subject: [TN] Conformal coating and BGA Hello All, Are their any restrictions of applying conformal coating on BGA components (Mil, Jedec, etc.)-i.e. on top of the BGA, avoiding underneath it, etc.? Thanks, Dr. Gil Zilber Technologist, Elta system Ltd. Tel. +972-8-8577240 Mobile +972-54-4983222 http://www.iai.co.il/site/en/iai.asp?pi=17887 The information contained in this communication is proprietary to Israel Aircraft Industries Ltd. and/or third parties, may contain confidential or privileged information, and is intended only for the use of the intended addressee thereof. If you are not the intended addressee, please be aware that any use, disclosure, distribution and/or copying of this communication is strictly prohibited. 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