Electronics Forum | Thu Sep 11 14:47:40 EDT 2008 | rarnold
For Production purposes, the problem goes away when a new solder paste lot is used. As I reported in my first message though, the problem keeps coming back. Most likely, paste lot is not the Root Cause (3 different lots now in the last 6mo). I rea
Electronics Forum | Wed Sep 18 18:41:17 EDT 2002 | davef
People have made good comments. Additional points are: * Your bridging is probably being caused by one or more of the following: [1] printing too much paste, [2] smearing the paste during placement or subsequent handling, or [3] paste slump during t
Electronics Forum | Wed Sep 18 12:31:16 EDT 2002 | dragonslayr
My suggestion is to conduct a Design For Manufacturing (DFM)study on the assembly in question. Pay particular attention to the pad sizes, component lead dimensions and satisfy yourself that those two factors are correct. Given that pads match compone
Electronics Forum | Wed Nov 07 11:56:44 EST 2001 | mparker
Pad spacing is just one element to consider. Your pad spacing is determined by the pitch (center to center distance between the leads). There are several good resources to find the appropriate pitch per device. Search the archives here or refer to th
Electronics Forum | Tue Aug 25 20:33:31 EDT 1998 | Karlin
| | | | Hi, | | | | Does anyone has experiences in reflowing Ceramic BGA and found solder wicking ? Solder wicking has the syndrome that solder being wick from the pad and ended up in the leads. | | | | We have rule out the possibility of not printin
Electronics Forum | Fri Sep 24 09:49:53 EDT 1999 | C.K.
Hi Folks: We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. The bridging is happening after coming out of reflow...one last thing t
Electronics Forum | Fri Sep 24 10:57:18 EDT 1999 | Earl Moon
| Hi Folks: | | We've been having bridging problems on our fine-pitch QFP's, despite thorough inspection of paste height, volume, and placement accuracies....profiles look good also. | | The bridging is happening after coming out of reflow...one la
Electronics Forum | Mon Aug 23 03:12:57 EDT 2010 | grahamcooper22
Possible route causes of bridging on fine pitch ICs are; too much paste (stencil aperture wrong), poor print quality (paste smudges during printing), pcb pads not flat depending on the solderable coating, paste has poor cold slump properties, too muc
Electronics Forum | Fri Aug 13 13:50:53 EDT 1999 | Brian Wycoff
| | | | | | Hello | | | | | | | | | | | | Having a problem with bridging on 20mil pitch qfp, only on the lead groups where squeegee goes over width of apertures. Using MPM sp-200 semi-auto, chem-etch stencil, 9-10mil width opening | | | | | | 100 du
Electronics Forum | Thu Aug 27 15:40:50 EDT 1998 | Justin Medernach
| | | | | Hi, | | | | | Does anyone has experiences in reflowing Ceramic BGA and found solder wicking ? Solder wicking has the syndrome that solder being wick from the pad and ended up in the leads. | | | | | We have rule out the possibility of not p
