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January 2007

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Subject:
From:
"Macko, Joe @ IEC" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Macko, Joe @ IEC
Date:
Fri, 5 Jan 2007 16:20:32 -0800
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Hello Fellow techs,

 

One of our CMs is having great difficulty developing a thermal profile for a
small, double sided, densely populated board with different  sized BGAs on
one side.  One of the BGAs is rather large and higher in thermal mass than
the surrounding smaller BGAs. The issue is that when he gets the solder ball
temperature of the larger BGA up to at least 205 C, the peak body
temperature of 2 adjacent but much smaller and thinner BGAs exceeds their
manufacturer's recommended peak body temperature of only 220 C by ~ 10 C.
The CM does not think he can make any more adjustments to the 9-heating zone
Heller oven to accomplish this task.

 

Does anyone have any suggestions/ideas on how to heat the larger BGA
sufficiently without over heating the smaller adjacent BGA components?.
Possibly, he can insulate the smaller BGAs with a piece(s) of tape on the
top (prior to assembly) to lower the body temperature - has anyone tried
this? 

 

Look forward to reading anyone's idea. thanks

Joe 

 


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