FIELD: manufacturing technology.
SUBSTANCE: invention relates to lithography and relates to a lithography system. Lithography system includes a base, an installed on the base optical column for projecting a pattern onto a target, a moving target holder, a differential interferometer module designed to measure the target holder displacement. Target holder and the optical column are provided with the first and the second mirrors, respectively. Differential interferometer module has a beam source configured able to provide three coherent beams, a beam divider unit, a beams coupler and beam receivers. Divider unit has one beam divider and divides the three beams into three pairs of beams each consisting of a measuring beam and a related with it reference beam. Measuring beams are directed onto the first mirror, and the reference beams are directed onto the second mirror. Beams coupler is intended for combining the three reflected measuring beams with related with them three reflected reference beams into three combined beams and projecting the combined beams onto appropriate beam receivers.
EFFECT: technical result is simplification of the system design.
20 cl, 12 dwg
