Abstract: A movement platform provided with a carrier (2) and at least as three spaced apart clamping means (3), wherein the clamping means each clamp the carrier at a contact point (13) and at least one globular contact surface (14) of the carrier, while at least one clamping means is provided with at least one displacement element (4) for displacing the contact point relative to at least the respective contact surface and/or at least the respective clamping means such that the carrier can rotate about at least two imaginary axes, while the normal forces (Fn) applied by the clamping means to the carrier are in approximately parallel planes, which parallel planes are approximately perpendicular to the tangential plane at the globular surface at the respective contact point.

Abstract: An embodiment of the invention may be applied to measure the positions of features in a alignment region on a mask with a sensor. The positions of the features in the alignment region are known from the design. A feature of which the position is measured, is identified by comparing the relative positions between measured features with relative positions known from the design. The known position of the identified feature is subtracted from a measured position of the identified feature to give the position of the mask.

Abstract: In an off-axis levelling procedure a height map of the substrate is generated at a measurement station. The height map is referenced to a physical reference surface of the substrate table. The physical reference surface may be a surface in which is inset a transmission image sensor. At the exposure station the height of the physical reference surface is measured and related to the focal plane of the projection lens. The height map can then be used to determine the optimum height and/or tilt of substrate table to position the exposure area on the substrate in best focus during exposure. The same principles can be applied to (reflective) masks.