Abstract
We introduce a dynamic fuse model for the damage done to a metal thin film by electromigration, and study the growth of a single crack that is perpendicular to the direction of the ambient current. As the crack length 2x grows large, the velocity of the crack tips v scales as v(x) approximately xalpha . We argue that the value of the exponent alpha is exactly 2. This result is in excellent agreement with our numerical work.