Electronics Forum | Thu Aug 17 22:22:29 EDT 2000 | C.J. Long
Hi erverybody: I am from a PCB shop. One of our product is with 19 X 19 ceramic BGA and my customer is experiencing 0.1 - 04 % failure of open trace on cornoer BGA pad. Substrate is FR4 with TG 135 degree C and delta Tg is well below 3 degree C. Tra
Electronics Forum | Fri Apr 17 14:08:44 EDT 1998 | Earl Moon
| Currently I am in the buisness of soldering bare die to the top surface of a copper heat sink. Is any one else | have some exprience in this process that can help. We heat a copper slug through a contolled atmosphere, place a preform then a bare
Electronics Forum | Tue Dec 26 11:26:00 EST 2000 | acahill
If you have a known problem with the parts, then Reject them back to the Vendor. It appears that you have a solderability issue. As for Tombstoning on 0402 chips, this could trace back to the stencil design and/or machine placement. Define Tombstoni
Electronics Forum | Mon Aug 21 19:35:51 EDT 2000 | Dave F
Kyung Sam Park: Sure, several causes of plastic QFP package delamination, other than humidity absorption, are: * Corrosion on component leads * CTE mismatch between leads and package materials * Package material adhesion strength degradation Wh
Electronics Forum | Thu Aug 24 13:51:24 EDT 2000 | Dr. Ning-Cheng Lee
Low temperature aggravates the mismatch in thermal expansion between solder and parts and between components and boards, therefore can induce earlier failure. The low temperature screening test should not be as effective when used on soft solders su
Electronics Forum | Thu Apr 16 08:07:05 EDT 1998 | Stan
Currently I am in the buisness of soldering bare die to the top surface of a copper heat sink. Is any one else have some exprience in this process that can help. We heat a copper slug through a contolled atmosphere, place a preform then a bare die.
Electronics Forum | Mon Sep 29 02:35:28 EDT 2003 | Sam
Hi Mantis. Has there been any changes in the BGA itself? One of our BGAs changed to a newer type, and after that we had problems with corner lifting. In that case problem was BGA's structure, there was mismatch in TCE between BGA's substrate and mo
Electronics Forum | Wed Aug 03 21:29:59 EDT 2005 | Ken
Yes, lead can promote fillet lift. In order to understand this defect you must begin looking at your lead frame mateials. some lead frames are more susceptable to this disorder. This is most likely a cte mismatch disorder. Lead contamination in
Electronics Forum | Fri Feb 17 11:01:47 EST 2006 | amol_kane
with lead-free solders, one would expect to find less instances of tombstoning. this is because SAC alloys are not eutectic and melt over a range of temp (usually 217-220 deg C) instead of at a single temperature. therefore the forces due to solder s
Electronics Forum | Wed Mar 22 21:27:45 EST 2006 | KEN
Find out the lead frame alloy. Cte mismatch can cause the same defect. Ran into this 3 years ago wave soldering with Tin-Copper.....okay, you caught me. I admit it. Wavemaster larry told me about this and I'm posting it under my name. Shameful, I
