Electronics Forum | Mon May 16 22:59:40 EDT 2005 | davef
We believe your problem is caused by the mismatch in CTE of the material ised in your BGA. In fact, this "potato chipping" [where the corners curl-up] is present in all BGA. The issue is the matter of degree. [Mismatching CTE is how old thermostats
Electronics Forum | Wed Feb 23 21:24:42 EST 2000 | Dave F
Chris: Whatever way you decide to define your pads, use the same type on the component and the board. Non-solder mask defined pad advantages: � No point-of-stress concentration at edge mask and solder ball � No CTE mismatch at edge mask and solder
Electronics Forum | Wed Feb 23 21:24:42 EST 2000 | Dave F
Chris: Whatever way you decide to define your pads, use the same type on the component and the board. Non-solder mask defined pad advantages: � No point-of-stress concentration at edge mask and solder ball � No CTE mismatch at edge mask and solder
Electronics Forum | Mon Jan 20 17:42:45 EST 2003 | jonfox
Double check the data sheets for your paste. Just as an example, ou Indium paste has a recommendation for the Heating, Liquidus, and Cooling stagees of reflow. They recommend a linear ramp up of 0.5 to 1.0 degree C. In the Liquidus stage, a peak t
Electronics Forum | Thu Dec 09 07:46:42 EST 2004 | davef
We did this for BGA pads, but have not thought about other types. So, this may or may not apply for those. Pad defined by:||Advantages||Disadvantages Non-solder mask||No point-of-stress concentration at edge mask and solder ball||Smaller pads have
Electronics Forum | Tue May 17 08:00:26 EDT 2005 | Bob R.
We went through this with one PBGA supplier recently and they were able to get the problem under control by fixing some of their molding processes that were inducing residual stresses. You can really see it in a thermal moire where you measure warpa
Electronics Forum | Fri Dec 09 07:10:36 EST 2005 | Mity-C
Good Morning, One problem of LF BGA's in a leaded process is the temps required to propperly collapse the BGA balls. If the BGA is LF, the alloy of the balls will not reflow until the temp reaches 217-245 C. SN 63/37 reflows at 183 C. If your profil
Electronics Forum | Thu Jan 05 15:42:26 EST 2006 | samir
Grant, The strength of the joint in a CCGA is the column for one...it's more ductile, made out of 90% Pb, and it's meant to compensate for the massive CTE mismatches between the ceramic and the board (ie the columns flex to relieve stress from the e
Electronics Forum | Mon Dec 05 17:53:04 EST 2005 | KEN
I hate to sound like a broken record but the industry has been placing lead free through-hole parts forever. Now all of a sudden its a problem??? Gold finish, silver, silver paladium, alloy 42, even pure copper. Reliability will be a function of t
Electronics Forum | Sun Feb 18 16:47:34 EST 2007 | darby
As I stated, the reply was direct from Indium, (thanks to Rich Brooks). The information regarding cool down rates should come from your paste supplier; not an oven supplier; not a generic article on lead free. I just went through the data sheets from