http://en.wikipedia.org/wiki/Black%27s_equation
I don't know how exactly current density is related to voltage, but if I had to guess that it somehow related to current, the current would drop if the temperature of the circuit rises due to increased resistance of the circuit. But then again I don't know anything about the amount of current flowing through any of my computer chips. I also wouldn't know how to calculate current density, even if I knew how.
What I want to understand is, which value has a bigger impact on the MTTF: higher voltages, or lower temperatures?
