Electronics Forum | Tue Sep 06 09:47:12 EDT 2011 | dyoungquist
We use a 40mil circle with the solder mask backed off another 40 mils (120mil circle) beyond that. Works good for us but not sure if that is an industry standard or not.
Electronics Forum | Fri Aug 23 01:40:14 EDT 2019 | sssamw
Such huge difference between low and high thickness will definitely cause paste accumulation on the squeegee side. Normally is 2 mil max difference.Yes, dispense maybe help for thicker paste or print two times.
Electronics Forum | Tue Dec 31 10:06:37 EST 2019 | emeto
This one is easy. Go to 5mil stencil and reduce apertures in width. try to have 10mil aperture width and 10 mil distance in between. If you give us numbers we will be more precise.
Electronics Forum | Mon Mar 23 16:38:09 EDT 2020 | emeto
Steve, On 16mil pitch I would try 12mil diameter on 5mil stencil, unless the BGA ball size is something unexpectedly huge.
Electronics Forum | Tue Sep 21 13:43:33 EDT 1999 | Glenn Robertson
| I've had some trouble pasting a test board for a MicroBGA trial. Most of the paste remains in the stencil apertures. | The stencil is 6 mil thick, laser cut and electo-polished. | The apertures are 12 mil in diameter with 20 mil pitch. | We are usi
Electronics Forum | Wed Dec 16 19:37:19 EST 1998 | Ron Costa
I have a mixed technology board ranging from 50 mil pitch devices to 20mil Qfp's to PBGA-352 at 1.27mm, and 6 Intel uBGA-48 at 30 mil pitch. With all these different package types i'm torn between using a 4 or 5mil thick stencil. The ball dia. is 14
Electronics Forum | Thu Mar 03 18:09:06 EST 2005 | gpaelmo
We also use Indium NC-SMQ92J. We do the same as mentioned per Russ. We reduce apertures mostly on QFP's with pitch of 25 mil or less (we place down to 15 mil QFP). All other apertures we keep 1:1. We print resnet 0805 size with no problems. You might
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 | Fri Sep 23 04:24:39 EDT 2005 | siverts
2.6 mil/pixel and a 4 mil/pixel cameras works maybe even better. It is sometimes a little bit difficult for the 1 mil/pixel cameras to accept parts; and it will take longer time to inspect a bigger QFP as it needs to take more pictures. We use 2.6 mi
Electronics Forum | Tue Feb 21 20:22:46 EST 2006 | mnguyen
Hi, I am having problem looking through IPC and finding according to ISO spec what should the paste height requirement vs stencil. EXAMPLE: The stencil is 5mils thick and according to the specs we have on paste height measurement the max height to be
