It's hard to get my son 3 months to sleep in the day. He is an ultra light sleeper. After patting for 15 min, he only sleeps for another 15 mins before he is awake again. Anyone has similar experience?

If you are patting your child to sleep, it means that he is relying on a sleep prop to help him fall asleep. Sounds like he may be an overtired child if he doesn't nap well during the day. So he can't really go into a deep sleep as well if he's overtired. My advice is to get him to bed early like 6-7pm and teach him to fall asleep on his own without your help. By the way, a good nap is at least 1.5-2 hours long. My 2 months old baby can nap for 1.5-2 hours each naps and sleep 7-9 hours overnight. It's important to foster healthy sleep habits for your baby so he doesn't get overtired. Remember you offer healthy food for your baby, you must also offer healthy sleep for them to allow them to develop well physically and mentally.