Electronics Forum | Thu Oct 21 14:02:32 EDT 1999 | Ron Costa
We are a contract manufacturer currently building a job with IBM CBGA-255 devices and 20mil QFP's that are close to each other. We use a 6 mil laser cut and electro polished stencil with one to one apertures on the BGA's. The customer is experiencing
Electronics Forum | Tue Jul 13 13:51:51 EDT 1999 | Earl Moon
| | | Hi all , | | | | | | We are trying to implement the micro-BGA technology at our plant. I need the clarification to the following points: | | | | | | 1. Is underfill required for micro-BGAs? | | | | | | 2. What type of stencil apertures are t
Electronics Forum | Thu Mar 29 12:05:38 EDT 2007 | cecil
OK, just finished our prototype build. PWB 7.5" x 10" 16 layers smallest pitch 17mil smallest BGA pitch 30mil (round apertures) smallest component 0402 total of 1492 placements 5 mil stencil foil (invar) Had numerous PQFN packages that always gave
Electronics Forum | Thu Jun 28 09:07:51 EDT 2007 | mika
Laser cut 0.13mm stencil thicknes works great for us. BTW, are we talking RoHS solder paste? We do reduce the stencil apertures to 88 % of the pads when we go for the RoHS solder paste. Otherwise we go fo 96% reduction in general with some excemption
Electronics Forum | Mon Feb 21 17:56:44 EST 2005 | davef
You want approximately 5 particles minimum across the smallest aperture. So in the case of a 0.8mm device, we use .017" pads with a round 0.020" aperture on a 6 thou thick stencil foils. Here, 0.020" diameter equals 0.50mm. This gives us 0.50/5=10
Electronics Forum | Thu Dec 15 11:06:05 EST 2005 | Samir Nagaheenanajar
You might wanna try a small reduction in your stencil aperture. For example, for a 30-mil pad go 26-mil square aperture with 8 to 10-mil radius on your corners. Also, look at your designs. Is there enough resist between your pad and ball? Another
Electronics Forum | Wed May 29 14:42:53 EDT 2002 | jaltland
I have another question about bga's and stencils. We were told by a manufacturer to use .012 square apertures for .009 dia balls. The original pick & place and reflow goes pretty well (over 95% good), however when we have to select components on th
Electronics Forum | Wed Dec 14 23:32:19 EST 2005 | jhernan9
Hi, I'm having a lot of problems with BGA's shorts, we are using 0.005" stencil aperture 1 to 1 (0.014)", the paste is centre (I can not measured the height)was verified using electronic microscopie, the placement is centre (I'm using local fiducials
Electronics Forum | Tue Sep 14 02:46:17 EDT 2010 | grahamcooper22
Hi Gani, Looking at the pictures in the report it looks as if there is a thin coating of solder on the pcb pad....but it looks like the BGA sphere was barely in contact with the pad. This could be caused by insufficient solder paste on this pad...may
Electronics Forum | Mon Aug 17 02:50:44 EDT 1998 | Bob Willis
| Have an SRT w/preheat, 18 layer board all copper, 456 BGA needs to be removed and replaced. The manufacturer is Chip Express and during reflow it warps up or down. Causing either opens or shorts on the corners. I was using gel flux with multiple
