tax return for a minor

My son earned just under $7000 working part time. He is 17 and in highschool.

He only had state taxes deducted - no federal.

When I put in all the info into turbo tax both federal and state say he qualifies for no refunds.

 

Do I still need to report via a income tax form being he is not entitled to a refund and earned less than $7000?

Is there a minimum he has to earn to be required to file taxes?