Comment This is not builder vs developer, it's contractor (Score 1) 716
If the developer was an independent contractor or freelancer, he would be required to fix his bugs on his own time (trust me, I've done it). If he is an employee, he would be paid his normal wage, and be at risk for termination should his employer feel it warranted.
Your boss can't make you fix bugs on your own time because you are an employee. If he takes issue with the quantity/severity of the bugs you produce, his his remedy is to fire you and replace you with someone more competent.