Electronics Forum | Sat Mar 24 19:49:29 EDT 2007 | mika
Aj, Many Thanks and I will of course share our experience about this. /Mika
Electronics Forum | Fri Apr 06 08:17:25 EDT 2007 | davef
Mika: What are the size and shape of the pads on: * Board * Interposer of component Are either of these solder mask defined?
Electronics Forum | Sat Mar 24 12:15:31 EDT 2007 | aj
I was referencing a qfn type package - apologies for any confusions. I have no experience with the package you are refering too. I would be interested to see how you get on. I will have a look at the datasheet if I can find it. Later, aj...
Electronics Forum | Sun Mar 25 12:21:35 EDT 2007 | diesel_1t
http://www.freescale.com/files/32bit/doc/package_info/AN2920.pdf hopefully this help you. also we always look on X ray for some misplacement; you can see like a dark circle and another lighter circle with an offset between both circles (meaning dar
Electronics Forum | Fri Mar 30 23:09:30 EDT 2007 | mika
We have now ordered a another stencil with square apetures with 20% overprint just because it is so difficult to get the solder paste to stay on the pcb pads without to get it stuck within the apertures. We have set the print speed down, the separati
Electronics Forum | Sat Mar 31 08:22:42 EDT 2007 | davef
Are you observing stencil design rules with regard to aspect and area ratios? For more: * IPC-7525 - Stencil Design Guidelines * A previous discussion http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=24848 * Other postings on stencil ratio
Electronics Forum | Sun Apr 01 09:26:13 EDT 2007 | mika
Thanks DaveF, I think the IPC-7525 - Stencil Design Guidelines (which is overall a pretty good guideline) does not perfectly apply in this case. I would rather go for a little bit over print, as for a CCGA; unless I misinterpreted the info. I really
Electronics Forum | Fri Apr 06 16:36:39 EDT 2007 | mika
Ah, I almost forget (forgot?) to mention that according to the Gerber files (which is the info we send to the PCB-house) the PCB land pattern for this LGA-36 0.35mm rounded pads and the boardhouse cannot achieve this. I understand them; 0.35mm pads,
Electronics Forum | Fri Apr 06 18:17:49 EDT 2007 | davef
Mika: Based on what we hear you saying, we're not so sure we have a problem with the board layout [1:1 between board and interposer pads, non-solder mask defines pads], but with the flawed execution of the layout. If your board fabricator decides to
