IR drop and electromigration

[k_90]

hi
Does anyone have any information on either IR drop and electromigration?
ie how to calculate it?

 

[Vamsi Mocherla]

For information on electromigration and IR drop, you can read any book on layout. Refer to IC Layout Basics or Art of Analog Layout. Both these books are posted on the board.

You can calculate IR drop by knowing the sheet resistance of the metal and as per formula R = Rsheet*L/W of the metal. You can get the metal sheet resistance from the foundry models. Even the foundry will give you information on the thickness of metal for the amount of current carried. A usual thumb rule is to keep a thickness of about 1um for about a milli-ampere of current.

I hope that it helps

 

[viren_s]

for iIR drop you must know the current in the line then calculate the resistance by the formula as in perivious topic . with that you can know the voltage drop in the line if that is in 1% of the voltage then acceptable (it depends on the circuit )

for electron migration it only depends on the current density , you can get the data that what current density the metal can sustain .
and 2nd at the corner there is more chance that electron migration can occour even if you have sufficent width so make corners with the angle 45 degree instead of 90.