He is too young to be in a bed, from an emotional regulation point of view. He needs to be in a cot, which may make for trickier parenting as you deal with sleep issues but will be much better for his sleep hygiene long term.
By leaving him in his bed hysterical and uncomforted (and ignored) in the mornings, you are creating very negative associations with his bed. In particular negative associations when he wakes up in his bed - which will give you a very difficult situation when he next wakes in the night for teething / illness / general nothingness that periodically do cause night wake ups.
You get the best results with baby sleep if you set your own emotional response as a positive one. I would aim to be kind, compassionate, caring but firm.
Make it as easy as possible for him to go back to sleep, or at least be relaxed and calm. That might mean bringing him into your bed, so that he gets used to 6.30am being his wake up time. If you dont want him in your bed, then you could lie down next to his. Snuggle and be loving with him, not cold and stand-offish. Help him feel comforted and soothed enough to relax.
Maybe he wont drop back to sleep but you want that morning time to be relaxed, still in sleep mode even if not asleep. So cuddled, slumbering, relaxed. It needs to be quite opposed to when you do get up at 6.30am - when be full of energy and ready to go. Do everything you can to keep high energy (ie crying or playing) out of any time before 6.30am.
At bedtime and naptime, try to keep those quiet and calm too. So not getting up or sitting up, not crying or being loud. Keep all associations with being in the cot (bed) positive, calm and relaxing. He should be expected to lie down, lie still and be quiet from as soon as he goes to bed, until its wake up time (6.30)
When he wakes, keep everything quiet and calm. It's OK if he doesnt go back to sleep, relaxing in bed can be just as good for him, but it does need to be a calm and non-stimulating time. His body clock will move to waking later if his body gets used to staying in a relaxed state until get up time (ie 6.30am). If he's used to waking up and facing a battle of wills from 5am (or whatever), that battle of wills is only reaffirming and worsening the early rising in his body clock.