Exposure apparatus

An exposure apparatus arranged to project a radiation beam onto a target portion of a substrate, the exposure apparatus comprising:

• a first substrate holder configured to hold the substrate;
• a second substrate holder configured to hold the substrate;
• a sensor holder configured to hold a sensor and/or detector;
• a first measurement device comprising a first alignment system comprising an alignment sensor configured to measure positions of a substrate alignment mark on the substrate;
• a second measurement device comprising a second alignment system comprising a further alignment sensor configured to measure positions of the substrate alignment mark on the substrate;
• a first scale arranged on a lower surface of the first substrate holder;
• and
• a first encoder head arranged to cooperate with the first scale, the first encoder head arranged to be located beneath the first alignment system and held by a stationary support.

An apparatus for an exposure tool arranged to project a radiation beam onto a target portion of a substrate, the apparatus comprising:

• a first substrate holder configured to hold the substrate;
• a second substrate holder configured to hold the substrate;
• a sensor holder configured to hold a sensor and/or detector;
• a first measurement device comprising a first alignment system comprising an alignment sensor configured to measure positions of a substrate alignment mark on the substrate;
• a second measurement device comprising a second alignment system comprising a further alignment sensor configured to measure positions of the substrate alignment mark on the substrate;
• a first scale arranged on a lower surface of the first substrate holder;
• and
• a first encoder head arranged to cooperate with the first scale, the first encoder head arranged to be located beneath the first alignment system and held by a stationary support.