Patent ID: 7110085

Claim:
A lithographic projection apparatus comprising: a radiation system for providing a projection beam of radiation; a support structure for supporting a patterning device, said patterning device serving to pattern said projection beam according to a desired pattern to form a patterned beam; a substrate holder comprising protrusions, each of said protrusions having an extremity, said extremities of said protrusions defining a substantially flat plane of support for supporting a substantially flat substrate, said substrate holder provided with a clamp to provide a pressing force for pressing said substrate against said extremities of said protrusions; said protrusions in an edge zone of said substrate holder arranged to provide a substantially flat overhanging of said substrate in relation to said pressing force of said clamp; and a projection system for projecting said patterned beam onto a target portion of said substrate, wherein said protrusions in an off-edge zone of said substrate holder are distributed so as to provide a substantially equal supporting area for said protrusions in said off-edge zone, said supporting area being defined by a Voronoi diagram distribution associated with at least a plurality of said protrusions.