Electronics Forum | Thu Apr 15 10:05:50 EDT 2010 | dwonch
Hi all, Long story ahead.... We are having issues with board vendors on some of our higher layer count (thick) boards. Specifically under BGAs with high aspect ratio vias (14:1). We are using ENIG finish and a lead free process. Basically we get t
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 | 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 | Thu Feb 07 20:53:51 EST 2002 | davef
Regardless of the technique used for the mounting pad shape or definition, isolation of the plated through hole [PTH] from the mounting pad is important. If the PTH is contained within the mounting pad, solder will wick down the PTH. The amount of
Electronics Forum | Tue Jun 05 03:56:52 EDT 2001 | JohnW
Flip Chip/uBGA Underfill Visual Standards The aim of this document is to produce some draft text and then select photographs to make up a draft visual standard for inspection. There is also a need to produce some reference material for C Scan image
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 | Mon Apr 02 20:47:22 EDT 2001 | davef
Cuppla questions for ya ... Where are the shorts [above the mask or between the mask and the laminate]? On the board, what material is between the copper traces and the mask? What type of solder mask(s) used by your suppliers? What are they using
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 | Fri Sep 10 11:45:09 EDT 1999 | Scott S. Snider
| scott. | I appreciate your sincere answer. | would tell me the hint about printer if i's possible | To tune our smt process we have to know what is the major X's | for defect. To know major X's with DOE we need a good measurement equipment.
Electronics Forum | Wed Aug 09 22:11:46 EDT 2000 | Dave F
Mark: The best routing of test vias for BGAs is to keep them far away from the device. We route test pads for the outer two rows of balls and use vias as test pads for the inner rows of balls. Your bottom-side layout is fine. Yes, on the top-side
