Are you relying on rms current density rules to manage interconnect temperature?

Introducting Ember™: thermal circuit analysis for electromigration reliability. 

Ember™ elegantly combines closed-form solutions to the heat equation with circuit analysis and parasitic extraction to solve the difficult problem of the detailed temperature distribution on IC interconnect without requiring a 3D field solver.

Ember™ uses only 

• the foundry rms current density rules,
• the spef file used for standard electromigration reliability (EMR) analysis, and
• the currents from your existing EMR analysis (although Ember™ can compute them, too),

so it adapts quickly to published process changes.  

Shouldn't you be using circuit analysis to manage interconnect temperature?