Directly from the NCAA Rule Book:
SECTION 4. Opportunity To Catch a Kick
Interference With Opportunity
ARTICLE 1. A player of the receiving team within the boundary lines attempting
to catch a kick, and so located that he could have caught a free kick or a scrimmage
kick that is beyond the neutral zone, must be given an unimpeded opportunity to
catch the kick (A.R. 6-3-1-III, A.R. 6-4-1-V and A.R. 6-4-1-X).
a. This protection terminates when the kick touches the ground, when any player
of Team B muffs a scrimmage kick beyond the neutral zone, or when any
player of Team B muffs a free kick in the field of play or in the end zone (Rule
6-5-1-a) (A.R. 6-4-1-IV).
b. If interference with a potential receiver is the result of a player being blocked
by an opponent, it is not a foul.
c. It is an interference foul if the kicking team contacts the potential receiver
before, or simultaneous to, his first touching the ball (A.R. 6-4-1-II, III, VII and
IX). When in question, it is an interference foul.