Abstract: An intermediate substrate holder for use in a lithographic projection apparatus, which holder can itself be held by a standard substrate holder in said lithographic projection apparatus and in turn can hold a non-standard substrate. The means for holding the non-standard substrate may be comprised of one of or both of a vacuum holding means and mechanical clamping means. The vacuum holding means may be comprised of: a vacuum space on which the non-standard substrate is placed; a barrier means around the edge of the vacuum space that closes off the vacuum space and that makes a sealing contact with the non-standard substrate; and a means for exposing the vacuum space to vacuum. The mechanical clamping means may be comprised of: two or more stationary positioning pins opposed by a slidable mechanism which is provided with at least one sliding positioning pin mounted thereon and which is biased to move the sliding positioning pin towards the stationary pins.