LITHOGRAPHIC APPARATUS COMPRISING AN INTERNAL SENSOR AND A MINI-REACTOR, AND METHOD FOR TREATING A SENSING SURFACE OF THE INTERNAL SENSOR

摘要

A lithographic apparatus (1) includes a projection system (PS) constructed and arranged to project a beam of radiation (B) onto a target portion (C) of a substrate (W), an internal sensor (201) having a sensing surface (202), and a mini-reactor (210) movable with respect to the sensor (201). The mini-reactor includes an inlet (220) for a hydrogen containing gas (226), a hydrogen radical generator (260), and an outlet (230) for a hydrogen radical containing gas (266). The mini-reactor (210) is constructed and arranged to create a local mini-environment (255) comprising hydrogen radicals to treat the sensing surface (202).