It has to hit the bat to be a foul ball. This was a swing and a miss. Or at least I thought it was.
If you swing and miss on the a third strike and the catcher drops the ball the catcher has to throw out or tag out the hitter before he gets to first base.
Otherwise it is an error on the catcher.
If it was a foul meaning the batter touched it at all and the catcher drops it he gets another pitch.
If a foul tip on a third strike and the catcher catches it the batter is out.