Electronics Forum | Thu Nov 07 10:59:11 EST 2002 | pjc
IPC-7525 "Stencil Design Guidelines" is a good reference document to have. Here are notes from a Tessera, (a major mBGA mfg.), study- "Application Note Solder Stencil Requirement for mBGA" The stencil aperture is to be square, equal in size to the l
Electronics Forum | Wed Nov 20 03:52:16 EST 2002 | iman
Hello, need help on intrusive reflow process, thanks in advance to the experts and general info sharing :) need some help to obtain answers, to following questions: 1) PCB is FR4, 1.6mm thick, 4 layers, what stencil thickness (stencil design guide
Electronics Forum | Sun Nov 24 09:54:24 EST 2002 | davef
On a HASL board that has poor wetting on the pad, consider looking further downstream in the process than your assembly shop. For instance, take a look at the bare boards. Look for solder mask bleed onto the pads. This will show-up on the outside
Electronics Forum | Thu Jan 23 14:19:56 EST 2003 | Mike Konrad
Hi Randy, No-clean flux needs to be activated in order to burn off the volatiles in the flux. This normally occurs partly during preheat and certainly during the reflow or soldering process. In most hand soldering applications, an operator applies
Electronics Forum | Thu Jan 22 15:51:08 EST 2004 | solderboffin
CBGA devices are a bit trickier to reball than run of the mil plastic devices. Once assemblied they are a bit like a sandwich when fitted to a PCB. From top to bottom it goes BGA device - Eutectic solder - High temp solder ball - eutectic solder -
Electronics Forum | Tue Feb 10 15:13:06 EST 2004 | patthemack
Hey Vinny, Sorry I haven't looked at this for a while. 3 things to try: Tombstoning- The ground plane side is larger because the solder mask allows for a little slop at the board shop (clearance around a pad of a few mils). Since there is not a defi
Electronics Forum | Tue Feb 03 06:52:45 EST 2004 | paul_bmc
About 2 years ago our company tried to go with a post reflow AOI inspection. This AOI was suppose to be able to inspect to a level class 3 product. **It is impossible** You cannot inspect for a heel fillet and inspecting for poor wetting is a very
Electronics Forum | Tue Apr 13 13:45:26 EDT 2004 | arcandspark
Ken you say reaching 218 to 221 C will give a homogenus solder ball. The pb free solder balls on the BGA reflow at 235 C to 238 C but I have seen when you combin to differnt types of solder say 63-37 and 10-90 you will atually lower the melting point
Electronics Forum | Tue Apr 13 19:14:25 EDT 2004 | Dreamsniper
Hi DaveF, To explain. The BGA that we have is from Motorola. The solder balls of these BGA's are Eutectic Solder and processed using a NC flux (as per info from supplier). So this means that the BGA pad and solder connections had NC flux process. W
Electronics Forum | Wed Apr 21 12:21:57 EDT 2004 | davef
Please help us understand your situation better. * How do �Having Problems W/ Parts Moving At Reflow� and �When the boards come out of the oven the pads look very wet from flux� relate to one another? * Tell us about solder, flux, reflow profile, and
