A semiconductor burn-in oven includes a housing including a burn-in chamber and an opening to the burn-in chamber surrounded by a front face, a heating device, testing circuitry, a door and a sealing mechanism. The door has an open position, in which the burn-in chamber is accessible through the opening, and a closed position, in which the door covers the opening. The sealing mechanism is configured to form a seal around the opening between an interior side of the door and the front face when the door is in the closed position. The sealing mechanism includes at least one sealing member having a recessed position, in which a gap extends between the front face and the interior side of the door, and a sealing position, in which the at least one sealing member closes the gap and forms the seal.