A lithographic projection apparatus is provided with an optical system
built into the wafer table for producing an image of a wafer mark that is
provided on the back side of the wafer. The image is located at the plane
of the front side of the wafer and can be viewed by an alignment system
from the front side of the wafer. Simultaneous alignment between marks on
the back and front of the wafer and a mask can be performed using a
pre-existing alignment system. The lithographic projection apparatus is
further provided with immersion system for providing a fluid between the
lens and the substrate.