Electronics Forum | Thu Mar 29 15:50:35 EST 2001 | tomgervascio
We've think that with seen solder shorts under BGAs after wave soldering the boards. In addition, it seems to be related to a certain soldermask configuration over the topside BGA vias.. THere is one vendor,A, that is applying soldermask after HASL,
Electronics Forum | Wed Aug 24 21:57:45 EDT 2005 | adeline_ko
The blistering is around the plugging via. I can forward you the pic. For the plugging process, I'm not too sure how they plug. What is the correct practise for the plugging via. Now, what they did is. They will do a tenting process for both side.
Electronics Forum | Thu Dec 15 11:06:05 EST 2005 | Samir Nagaheenanajar
You might wanna try a small reduction in your stencil aperture. For example, for a 30-mil pad go 26-mil square aperture with 8 to 10-mil radius on your corners. Also, look at your designs. Is there enough resist between your pad and ball? Another
Electronics Forum | Wed Feb 14 21:14:45 EST 2001 | davef
BGA Shorting 1 Damaged mask in between the BGA pad and via on the substrate. 2 Poor print registration. 3 Poor via segregation from the pads? Are they tented or is there just a dam in between? 4 Review the profile. You can run into a number of p
Electronics Forum | Wed Aug 09 16:30:43 EDT 2000 | MarkS
Has anyone had (successful) experience placing testpoint vias under BGAs? We already have conventional vias, but we're contemplating converting them into testpoints (probably by enlarging the bottom-side copper diameter to .036" and opening the bott
Electronics Forum | Tue Mar 13 17:26:07 EST 2001 | blair
1) We could press on BGAs and the boards would boot 2) This is basic boot up yield 3) We are now getting stpe by step inspection data going fwd. 4) So, Stencil design could be a critical factor. Any documented guidelines? 5) Yes DFX was done - mostl
Electronics Forum | Mon Mar 15 16:07:32 EST 1999 | Earl Moon
| | After rmoving a BGA (plastic)to correct unexplained shorts | | I installed another BGA using flux only. | | Checking on an X Ray machine and found two shorts. | | | | can anyone give a good explenation ? | | | | Thanks | | | | Ron | | | Ron,
Electronics Forum | Fri Mar 19 08:51:57 EST 1999 | Justin Medernach
| | | After rmoving a BGA (plastic)to correct unexplained shorts | | | I installed another BGA using flux only. | | | Checking on an X Ray machine and found two shorts. | | | | | | can anyone give a good explenation ? | | | | | | Thanks | | | | |
Electronics Forum | Thu Jul 29 11:34:27 EDT 1999 | Justin Medernach
| | | | | | Presently protos of micro-bgas (80i/o) pitch .030/.031 | | | | | | 12BGA per assembly | | | | | | | | | | | | The board is a (.062, 4 layers) FR-4 using Dry film | | | | | | Pads .014inch | | | | | | Vias within footprint .020inch | | |
Electronics Forum | Thu Jul 29 15:29:30 EDT 1999 | Earl Moon
| | | | | | | Presently protos of micro-bgas (80i/o) pitch .030/.031 | | | | | | | 12BGA per assembly | | | | | | | | | | | | | | The board is a (.062, 4 layers) FR-4 using Dry film | | | | | | | Pads .014inch | | | | | | | Vias within footprint .02
