Windows 7: Electromigration and temperature

Hi,

I was just looking at Black's equation that relates Mean Time To Failure and current density and temperature for electronic component degrading due to electromigration.

Black's equation - Wikipedia, the free encyclopedia

I had posted a link in Tom's Hardware overclocking forum to someone who had used it to make estimations of the effects of increasing temperature and voltage on the MTTF. It got censored by the moderator, I got upset and got banned

So making some assumptions, mainly:
Q= activation energy = ~.81 EV (e.g. copper)
n=current exponent = 2
current is proportional to voltage

I calculate the change in MTTF for a couple of extreme changes when overclocking



Change voltage from 1.2V to 1.4 volt
%change in MTBF = -27%

Change in temperature between 50 and 70 c
%change in MTBF = -82%
for a 50 to 60c change it would be -57%

So these are just simplified estimates and the effects depend a lot on what the effective activation energy is. I know these can be correct or the whole picture since running some processor at 1.4V certainly will reduce their life more than that. And it also depends on your usage - the estimate assumes 24x7 at these voltages or temperatures.

I wanted to illustrate the importance of the temperature term, which is exponential vs the current, which is quadratic. Keep it cool.