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US 7,352,441 B2Granted
Sensor unit, exposure apparatus, and device manufacturing method
AssigneeCanon Kabushiki Kaisha
InventorMakoto Ogusu
Life of this patent
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Abstract
A sensor unit includes a substrate that has a first mark, and a second mark used to specify a position of the first mark, a sensor for detecting light that has transmitted through the first mark and the substrate, and a light shielding portion, provided between the second mark and the sensor, for shielding the light from the second mark against the sensor.
Claims7
A sensor unit comprising:
- a light-transmissive substrate that has a first mark, and a second mark used to locate a position of the first mark;
- and
- a sensor for detecting light that has transmitted through the first mark and the substrate,
- wherein the substrate includes a light shielding film of a predefined thickness,
- wherein the light shielding film has the first mark and the second mark,
- wherein the first mark is an opening that is arranged on the light shielding film, and
- wherein the second mark is a step that is arranged on the light shielding film and is shallower than the predefined thickness.
4 more elements
Dependencies are inferred from the claim text.