Die Size Vs. Temperature Cycles to Failure Posted by Amanda M. Hartnett Thursday, July 31st, 2008

Solder TIMs are the bonding and joining material used to connect small, powerful dies to their substrates.  Some of these dies are exposed to severe temperature conditions which cycle into opposite extremes during device operation.  In April, Dr. Rudiger Bredmann with the University of Applied Sciences published an article about the reliability of these dies.   

His article highlighted a point contrary to the theory I am familiar with, which is the negative thermal reliability issues associated with a shrinking die size.  Although a shrinking die size does typically lead to a hotter chip which is difficult to cool, from a solder TIM perspective, a larger die is more heavily stressed by slow operating temperature cycles. 

For this reason, Bredmann cites a trend that the larger the die size and solder TIM is, the fewer numbers of temperature cycles it takes for failure.  It is written that the number of cycles to failure is “inversely proportional to the size (radius) of the solder joint squared.   

Posted by Amanda M. Hartnett at 19:51 PM (July 31st, 2008)

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