Electronics Forum | Mon Oct 13 13:49:29 EDT 2003 | mrmaint
Does anyone know of a standard stencil thickness for BGA'S. We currently use 4 to 5 mil stencils depending on component mix. Is an aperature reduction required for BGA'S. If so what percentage. Any help would be greatly appreciated. Thanks MRMAINT
Electronics Forum | Thu Sep 12 01:49:28 EDT 2002 | ck
Hi all, Any stencil opening recommendation for 20mils pitch mirco BGA. Currently, using 12mils round opening, 5 mils thickness. Seen to have weak joints as it crack after Ict testing. thks
Electronics Forum | Sun Oct 06 22:23:05 EDT 2002 | CH
Hi Eric, How to access to the Compaq Houston reprot. regds
Electronics Forum | Mon Oct 07 09:06:20 EDT 2002 | davef
Look here: http://www.smta.org/knowledge/proceedings_abstract.cfm?PROCEEDING_ID=898
Electronics Forum | Thu Sep 12 09:15:29 EDT 2002 | mhoughton
I have printed and placed similar devices in high volume with exactly this spec for a couple of years with no problems, are you using laser cut stencils and what type of solder paste are you using? and what is the end use of the product as it may nee
Electronics Forum | Wed Oct 02 15:08:37 EDT 2002 | Eric
See Fiske first line. I'd bet You are bending or catching the assembly in the ICT. How many probes at 8OZ each? do you use on that ICT? 800 probes = 400lbs. See "Flexure induced failure of BGA solder joints" by Compaq Houston TX
Electronics Forum | Mon Oct 13 19:04:47 EDT 2003 | davef
Aperture size should vary with the component [pitch]. That size should be the same a the pad size. So, generally pinching is not required. Indium discusses BGA apertures on their site [ http://www.indium.com ]
Electronics Forum | Wed Sep 25 11:11:14 EDT 2002 | xrayhipp
Try .005 or even .004 thick laser cut electopolish stencil and reduce grain size of paste. Go with 400 or 25 in the case of AIM. We had a similar prob.
Electronics Forum | Thu Sep 12 09:12:22 EDT 2002 | mhoughton
I have printed and placed similar devices in high volume with exactly this spec for a couple of years with no problems, are you using laser cut stencils and what type of solder paste are you using? and what is the end use of the product as it may nee
Electronics Forum | Thu Sep 12 11:26:11 EDT 2002 | scottefiske
CK, If joints have been validated prior to ICT (under BGA Scope), more often than not repeatable joint fractures are due to undo stress being placed on the component during ICT test. Verify ICT probes and fixture. If after proving out fixture/pin com
