Abstract:
An optical sensor apparatus (1) for use in an extreme ultraviolet lithographic system is disclosed. The apparatus includes an optical sensor comprising a sensor surface (3) and a removal mechanism (5) configured to remove debris (6) from the sensor surface. Accordingly, dose and/or contamination measurements may be carried out conveniently for the lithographic system.
Abstract:
A contaminant trap apparatus (10) arranged in a path (R) of a radiation beam to trap contaminants emanating from a radiation source (50) configured to produce the radiation beam is disclosed. The contaminant trap (10) apparatus includes a rotor (10) having a plurality of channel forming elements (11) defining channels (ch) which are arranged substantially parallel to the direction of propagation of the radiation beam, the rotor (10) including electrically chargeable material and arranged to be electrically charged as a result of the operation of the radiation source (50); and a bearing (20) configured to rotatably hold the rotor (10) with respect to a rotor carrying structure (30), wherein the apparatus is configured to (i) control or redirect an electrical discharge (10) of the rotor (ED), or (ii) suppress an electrical discharge (ED) of the rotor (10), or (iii) both,(i) and (ii).