Patent ID: 9395635
Filing Date: 2016-07-19
CPC Classification: G03F

Claim Text:
1. Position device arranged for determining a position of an alignment beam spot on a position mark of a substrate ( 313 ; 513 ), said substrate being provided with an at least partially reflective position mark comprising an array of structures, the array extending along a longitudinal direction of the mark, wherein said structures are arranged for varying a reflection coefficient of the mark along the longitudinal direction, wherein said reflection coefficient is determined for a predetermined wavelength, said position device comprising: an alignment beam source ( a beam intensity detector ( an optical system arranged for focusing the alignment beam on the position mark and for guiding the reflected alignment beam on the beam intensity detector, wherein said optical system comprises: wherein said beam intensity detector is arranged for detecting a light beam intensity for only the zeroth order reflection of the reflected alignment beam and adapted for providing a signal representative of the reflected alignment beam intensity, said signal representing the position of the beam spot on the position mark as the beam spot is moved over the position mark along the longitudinal direction.