They will play Maharashtra in the first semi-final, while defending champions Services take on Goa in the second one.
With their comprehensive win, Tamil Nadu not only improved their goal tally but also topped the pool.
Both the semi-finals are slated for March 11, while the title clash will take place on March 13.
Tamil Nadu's A Reagan struck three times to give his team a solid lead and was loudly cheered by the spectators.
After a goalless first half, TN mounted heavy pressure and opened their account in the 52nd minute through Reagan.
The southern team added two more goals in the 68th minute and 87th minute through Reagan to make it 5-0 against a listless Punjab.
Tamil Nadu has never won the prestigious national football trophy though it appeared in the final two times.