Device and method for positioning a photolithography mask by a contactless optical method

A device for positioning a mask relative to the surface of a wafer with a view to the exposure of said wafer, comprising:

• first positioning means configured for holding and moving said mask and said wafer in relation to each other;
• imaging means configured for producing at least one image of the mask and of the surface of the wafer according to at least one field of view with an imaging beam, so as to image positioning marks of said mask and of said wafer simultaneously in said field of view;
• and
• at least one optical distance sensor configured for producing a distance measurement between the surface of the wafer and the mask in the field(s) of view with a measurement beam which passes at least partially through the imaging means to form a measurement spot in the field(s) of view,
• wherein the imaging means are independent from the at least one optical distance sensor, and the imaging beam is different from the measurement beam.