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Analog Verification >> Analog Performance Verification >> Why IC temperature is limited to 150 degree?
https://designers-guide.org/forum/YaBB.pl?num=1395817756

Message started by angel on Mar 26^th, 2014, 12:09am

Title: Why IC temperature is limited to 150 degree?
Post by angel on Mar 26^th, 2014, 12:09am

Hello every one. I would like to ask one question. When we design IC chip, or read the datasheet, we can often see the IC operating temperature is limited to 150 degree. I would like to know the reason for it. Could you please give some evidence for it? g.g., paper, article, book...

Title: Re: Why IC temperature is limited to 150 degree?
Post by Johan Dijkhuis on Apr 10^th, 2014, 9:24am

When going above this temperature numerous reliability problems pop up, some of which are:
-purple plague at aluminium bondpads with gold wires (see http://en.wikipedia.org/wiki/Purple_plague)
-electro-migration in aluminium gets very problematic (http://en.wikipedia.org/wiki/Electromigration)
-NBTI and PBTI can get very high (http://en.wikipedia.org/wiki/Negative_bias_temperature_instability)

Some none-reliability problems:
-leakage can get very high
-transistor models might be less reliable (they are not tested)

Usually the design manual specifies reliability at different temperatures, and usually 150 C is a lot worse than 125 (if it is specified at all, a lot of processes are supposed to stay at 125 C maximum).
The 150 degrees limit will be based on history, it is not a hard limit but common process qualification stops at 150, so above that you'll have to re-qualify the whole thing. It might also be very hard to get it pass unless it is only at 150 C for a short time, and you might get unknown reliability problems.

Title: Re: Why IC temperature is limited to 150 degree?
Post by Johan Dijkhuis on Apr 10^th, 2014, 2:03pm

Just found some useful links in this thread: http://www.designers-guide.org/Forum/YaBB.pl?num=1394735572. NASA has really extreme requirements, but some mission lifetimes are hours, not years.