Electronics Forum | Fri Sep 08 04:45:17 EDT 2000 | PeterB
As per Travis's reply it could be something other than the reflow process. Another good one is if the printed PCB's have been cleaned down due to print misregistration etc.. If not properly controlled paste residues can remain distributed about the p
Electronics Forum | Mon Mar 27 08:28:48 EST 2000 | Mark Alder
Dear Robert The reason for the bridging problem you are experiencing on your BGA's is due because of too much solder. The PCB pads need to be at least 15% larger than the sphere size of the BGA balls. If you are not using C4 (63/37) BGA spheres and
Electronics Forum | Mon Jun 18 16:48:00 EDT 2001 | Gil Zweig
We have found a significant number of PBGA problems associated with physical deformation of the package. Deformations such as dishing (potatoe chipping) and delamination under the die (popcorning). These can be detected by x-ray by the variation patt
Electronics Forum | Tue Jul 24 14:00:08 EDT 2001 | Steve Schrader
Greg, Yes, I did my tour of duty. Is your boss back from Bermuda yet? If so, tell her to check her email! Thanks. BTW, there could be a benefit to moving parts, but that would be dictated by your ability/inability to achieve a proper reflow prof
Electronics Forum | Fri Jun 14 18:01:04 EDT 2002 | john_wsme
Dave and Russ, Today we modified the profile to ramp up slowly and have longer preheat time. The result is great, 0 out of 5 without bridging. I did review the FAB design and seen the pad is much biger than ball size. So I guess it is the problem.
Electronics Forum | Fri Sep 27 13:53:27 EDT 2002 | pr
We used it only for operator verification of placement accuracy, your boardhouse should be able to show you examples of what they look like. They basically outline the outside edge (corner)of the part so you have a visual, after placement (since you
Electronics Forum | Wed Jul 09 19:05:06 EDT 2003 | randywomack
LOZ. Under-cured or out-of-spec(sloppily) applied resist is realistic. What other physics: Shiny resist surface is more prone to balls then matte finish. How about an operator eating fish & chips before handling the boards. Don't laugh... ... saw th
Electronics Forum | Thu Jan 15 10:08:54 EST 2004 | ADAM
Guys Does anyone have any design rules for a 121 pin BGA . The pitch is 0.031 thou, the ball diameter is 0.0115 thou . I would like to know the following : Pad and via sizes/type on the bareboard ? Stencil thickness and aperture size/sytle ? Solder
Electronics Forum | Fri Feb 13 11:46:23 EST 2004 | Jack
Is your customer trying to reduce voiding? If the device is using Sn90 / Pb10 and the paste is Sn63/Pb37 the board will melt first. However, if both solders are 183C eutectic, it's a tossup? PCB design, copper weight, bga type (pbga, micro bga, Tbg
Electronics Forum | Wed Feb 01 08:27:29 EST 2006 | Chunks
I haven't seen a hydrometer used in years. Are you still foam fluxing? There used to be automatic units available, but with the advent of the spray fluxer, they may have dried up. If you are still foam fluxing with alcohol thinner, place ping pong
