In an immersion lithographic apparatus, bubble formation in immersion liquid is reduced or prevented by reducing a gap size or area on a substrate table. The work station includes a ballast compartment in the main housing into which ballast material may be placed to stabilize the work station. The method also includes electronically determining an elevation and a shape of the silicon island by tracking the bright dot during the meltdown process. The pet bed and the extension areas may be provided with mating attachment members to removably secure the overlay to the pet bed.