Thanx to all for reply..
Actually the distance between two gate is not less. Its quite big in length, where in normal case we can use metal. But specifically here they have asked to rote by poly. Also there is not a area problem.
What I cud think, is , as poly is more resistive, there wud be more resistance to electrons/current to LEAK out of poly, i.e. if some other meatal paths/route are running near to poly path , leakage (by capacitive/inductive coupling) would be less as compared to metal. If we use metal instead of poly, there can chances of
leakage (by capacitive/inductive coupling). And there may be specific requirement for that route/signal to have less leakage.
Let m know if I am correct ....
thanx