It also happened to me. I used to wake up at 7:15, snoozing up until 7:30, which was very bad for my morning routine. Putting the alarm clock on the other side of the room helped, but when I tried to set the waking time at 7:00, I would just get up, snooze and go back to bed. Now I'm trying to set it to 7:10 and it seems to work well.

There probably is a subconscious set point which needs to be adjusted gradually. You also need stuff to do when you wake up: if you wake up just for the sake of it, your subconscious will know and put you back to sleep.