Electronics Forum | Wed Jun 29 17:38:16 EDT 2005 | GS
Several years ago, we had almost same pbm, best results have been obtained by using water soluble paste (those time the old AM1208). Any way, to get a good toe meniscus is not so easy. Talking about CTE, keep in consideration the internal die of TSO
Electronics Forum | Thu May 26 21:07:22 EDT 2005 | KEN
This is caused by cte mis-match. The balls in the corners are short and fat. The balls near the null point are tall and more normalized. I don't remember what the zone settings were... BTU VIP98 BS was probably 22-25 IPM
Electronics Forum | Sat Mar 01 08:17:40 EST 2003 | davef
You're correct that the FR4 is probably the best choise. The majority of the problems in developing your reflow recipe is going to come from the CTE mismatches in the CCBGA , CBGA and PBGA that you put on the board. The other side says given the pr
Electronics Forum | Wed Jan 12 13:27:42 EST 2005 | carobin
The two options I see are (not including underfill): 1) Have complete conformal coating coverage of all balls with no webbing in between balls because of CTE mismatches. If all the balls are not coated we see failure in humidity testing. or 2) Sea
Electronics Forum | Tue Jul 25 12:14:39 EDT 2006 | russ
All my studies led me to believe that it was CTE mismatch of this package. Altera was of less than 0 help in this matter. The other possibility was an ICT test fixture. Unfortunately (?) the design life of this product was at end and the new design
Electronics Forum | Mon Aug 21 20:20:18 EDT 2000 | Dave F
Hi CJ: I guarantee you that the portions of you BGA that will physically move the most as a result of changing temperature are the corners. For this very reason, many BGA have BT substrates that have a tg of 210�C. I would demonstrate the potentia
Electronics Forum | Thu Sep 10 10:07:46 EDT 1998 | J.H Kim
I'm very familiar with the great board space savings of BGA and all the "claims to fame." However, can someone out there tell me if any concern exist in the inspection realm. Additionally, solder cracking, CTE mismatches, no leads for stress relief,
Electronics Forum | Wed Jul 09 09:27:02 EDT 2003 | MA/NY DDave
Hi Saw a Cross Section picture and thought of you You noted above that you couldn't find any pictures or descriptions of your problem in a few well known sources. It probably is not what you are experiencing yet a soldering defect called land lift
Electronics Forum | Wed Sep 15 17:31:40 EDT 2004 | GS
Once you verified for correct profile ( consider CTE mismatch) make sure before you remove PBA from fixture, the temperature is almost at room temperature. If by removing PBA from fixture,and the PBA gets a little bent (warped) just in the area where
Electronics Forum | Thu Jul 12 20:20:31 EDT 2007 | seankim10
I�m having problem with PCB with 16mil thickness due to warpage. the board convex up in the middle after 1st reflow. It seams the warpage is caused by CTE mismatch between PCB and multiple TSOP's, which are covering ~80% of the bottom side board area
