Electronics Forum | Tue Apr 29 11:18:16 EDT 2008 | julienvittu
basically your problems come from the copper balance top and bottom side we are using substrate down to 0.18mm (semiconductor industry/ Bga package / SIp business) you have to respect 5% difference maximum between Top and bottom side otherwise you
Electronics Forum | Fri Dec 03 18:17:12 EST 1999 | Dave F
Dave: There's lots of stuff on the web describing BGAs. Examples are: http://www.smtnet.com/bookstore/publications/0speckdo1/s1.html http://www.smtnet.com/bookstore/publications/0shutcco1/ch1p2.html http://www.citizen-america.com/OEM/bga/process
Electronics Forum | Tue Feb 19 11:08:22 EST 2002 | Chris Anglin
Guideline for Tenting Interstitial BGA Vias It is difficult to give a complete recommendation on via tenting without an idea what process conditions are required (ex: wave pass, double reflow, rework etc.). Via Pads (as Test Points) - On Bottom
Electronics Forum | Tue May 12 16:04:24 EDT 2009 | microdot
hi, we have recently got a PS-400 BGA reflow from china. has hot air top heater, IR & hotair bottom heater and 6 IR bottom heaters. We are able to handle all type of desktop boards but in few of the laptop boards we still have problem. The profiles
Electronics Forum | Wed Apr 05 13:59:56 EDT 2000 | Kal C.
Hi Emmanuel, There is lots of info. in SMTNet archive (I think 98 Sept-Dec). I had a lot of problem with PBGA and certain uBGA with their PCB base material (FR-X) and encapsulant. Wolfgang is correct. We had to reprofile our reflow oven , qualify an
Electronics Forum | Thu Mar 01 19:38:12 EST 2007 | Wayne
1) run the BGA side first. set the bottom temp lower (if your reflow oven have top and bottom temp setting) for connector side while doing your 2nd reflow. 2) run the BGA side first with your normal leadfree paste, and run the connector side with low
Electronics Forum | Tue Mar 09 20:08:08 EST 2004 | davef
Warping BGA are the usual cause of shorts in the corners and are usually caused by the reflow profile. BGA have a natural tendency to warp due to CTE and package thermal mismatch, as you have seen at rework. The PBGA will go from a bowl shape to an
Electronics Forum | Fri Aug 10 04:19:05 EDT 2001 | wister
There are lots of voids at solder joint of chips,the thickness of multilayer pcb is 3.2mm,top side have lots of chip component and bottom side has several BGA and QFPs.For top side profile,the preheat time is about 100s,soak time is about 75s,time ov
Electronics Forum | Thu Jul 15 14:55:24 EDT 1999 | JohnW
| I'm designing a board where the parts will only fit if I do one of the following: | | 1. Put BGAs on both sides | | 2. Put BGAs on top, smt TSOPs directly underneath and using blind vias to keep the real estate on the bottom side below the BGA pa
Electronics Forum | Thu Oct 12 08:12:51 EDT 2006 | realchunks
I have, but not for what you are trying. Different ovens and styles react differently when you try this, so you have to experiment to see how far you can go. Why do you think different temps top and bottom will solve the coplanairty issue? Is this
