Lithographic apparatus and device manufacturing method
AssigneeASML Netherlands B.V.
InventorsJohannes Catharinus Hubertus Mulkens, Nicolaas Ten Kate
Life of this patent
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Abstract
A difficulty of contamination interfering with a grid plate positional measurement system is addressed. In one embodiment contamination is prevented from coming into contact with the grating or the sensor. In an embodiment, surface acoustic waves are used to detach contamination from a surface of the grating or sensor.
Claims21
A lithographic apparatus comprising;
- a substrate table configured to hold a substrate;
- a reference frame;
- a grating attached to the substrate table or the reference frame;
- a sensor attached to the other of the substrate table or the reference frame, the sensor configured to detect radiation redirected by the grating to measure the relative position between the substrate table and the reference frame;
- and
- a hairier associated with the grating or sensor, the bather positioned to hinder contamination from reaching the associated grating or sensor and having a surface facing away from the associated grating or sensor at a distance between 300 vim and 5 mm from the associated grating or sensor.
A lithographic apparatus comprising:
- a substrate table configured to hold a substrate;
- a reference frame;
- a grating attached to the substrate table or the reference frame;
- a sensor attached to the other of the substrate table or the reference frame, the sensor configured to detect radiation redirected by the grating to measure the relative position between the substrate table and the reference frame;
- and
- a contamination removal device configured to remove contamination from a surface by changing a property of the surface, the surface being a surface of (i) the sensor, or (ii) the grating, or (iii) a barrier at least partly covering the sensor or grating, or (iv) any combination selected from (i)-(iii).
A device manufacturing method comprising projecting a patterned beam of radiation onto a substrate held on a substrate table, wherein a position of the substrate table relative to the projection system is measured using a grating and a sensor, wherein a barrier is positioned to hinder contamination from reaching the grating or sensor, the barrier having a surface facing away from the associated grating or sensor at a distance between 300 μm and 5 mm from the associated grating or sensor.
A method of removing a particle and/or droplet on or preventing a particle and/or droplet from adhering to a surface of a grating, a sensor or a barrier at least partly covering the sensor or the grating, the method comprising changing a property of the surface.
Dependencies are inferred from the claim text.