Electronics Forum | Wed Feb 09 12:31:54 EST 2005 | russ
We are not doing this right at the moment but I have done it with great success. Of cource it depends on your pad layout we have a 20 mil gap in between pads, we printed at 10 mil wide with a 5mil stencil. I will try to find the glue we used, I kno
Electronics Forum | Wed Mar 30 16:07:24 EST 2005 | Dreamsniper
If there's no shear strength standard for solder joint, how will I define my pad width and length then. I have a 8.5 mils width and my component lead width is 8.66 mils based on manufacturer's minimum width specification. How will I identify that it
Electronics Forum | Mon Apr 11 08:47:34 EDT 2005 | Rob
There's not many ways of doing it on the cheap except... Buy a second hand universal GSM1 with VME 630 vision, 0.5 mil per pixel camera & some expensive ceramic nozzles for the 0201's. This will be quite slow & the software quite awkward but lookin
Electronics Forum | Thu Jun 16 18:19:05 EDT 2005 | Jason Fullerton
If the uBGA has aperatures that are 0.25mm square, you need to use a laser cut foil no thicker than 3.75 mils to get an area ratio of 0.67, which is the minimum rule of thumb - that's too thin! Electroform would probably work up to 4.5 mils thick.
Electronics Forum | Thu Jun 16 09:13:46 EDT 2005 | russ
We use a 5 mil for 16mil pitch QFPs, Make sure that the stencil has been polished. Type 3 paste. We have used lead free no-clean, lead no-clean, and water soluble lead pastes for these packages. We set the printer for a slow stroke .7 in/min. wi
Electronics Forum | Wed Aug 31 09:06:11 EDT 2005 | PWH
Agree with Siverts. We do a build that has 0.3mm pad diamter BGA (0.8mm pitch - distance from pad center to pad center) and 0.5mm dia. BGA balls. Stencil specs. are: 5 mil. thickness, square BGA pad aps. (1:1, 0.3mm square aps), laser cut. Seems
Electronics Forum | Wed Aug 31 11:02:28 EDT 2005 | Jason Fullerton
We are using one BGA that has 7 mil bumps on a 20 mil pitch. We use the manufacturer's recommended pad and aperature layout, which is an 11.8 mil square overprint on a 6 mil land. At 11.8 square, you need to use a 4 mil laser cut or a 5 mil e-form st
Electronics Forum | Fri Sep 30 19:14:35 EDT 2005 | DasonC
The stencil is 5 mil thick and the aperture is 12 mil sq. We found open but can't detect by x-ray. The process which we are using is no clean TIN/LEAD. Just thinking the ball size variance from 0.35~0.45mm per IPC-7095, in worst case scenarios, th
Electronics Forum | Tue Mar 07 14:03:45 EST 2006 | slthomas
The cheapest method I've found to measure anything in that size range is a reticle for a stereo microscope. I don't remember the resolution but it was 2 or 5 mil, I think. It's not rocket science but it's a nice tool for small scale measurements tha
Electronics Forum | Thu Mar 30 10:21:44 EST 2006 | Dan
Sorry about that(My bad), they are copper. I believe the same thing, we need to reduce the appatures as we are already at 5mil. Our main problem is the customer...Their tests were failing and for some reason they touched that part up, and then the un
