Method of determining a focus position for a substrate exposure process and substrate exposure apparatus capable of performing the same
First Claim
1. A method of determining a focus position for a substrate exposure process comprising:
- measuring an intensity of projected light at a projection plane, the intensity of the projected light having at least one peak;
measuring variations of the intensity and the at least one peak at the projection plane while moving the projection plane in an optical axis direction of the projected light; and
determining a focus position based on the variations of the intensity and the at least one peak.
1 Assignment
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Accused Products
Abstract
In a method of determining a focus position for a substrate exposure process and a substrate exposure apparatus capable of performing the same, a reticle having a light-transmitting region may be illuminated by an off-axis illumination light. A projected light, which is transmitted through the reticle and a projection optical system, may be detected by a light sensor disposed on a substrate stage. An intensity of the projected light measured at a light-receiving surface of the light sensor may vary in accordance with positions of the light-receiving surface. The focus position may be determined based on the variations in the intensity of the projected light.
5 Citations
17 Claims
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1. A method of determining a focus position for a substrate exposure process comprising:
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measuring an intensity of projected light at a projection plane, the intensity of the projected light having at least one peak;
measuring variations of the intensity and the at least one peak at the projection plane while moving the projection plane in an optical axis direction of the projected light; and
determining a focus position based on the variations of the intensity and the at least one peak. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A substrate exposure apparatus comprising:
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an illumination optical system providing an off-axis illumination light;
a reticle stage supporting a reticle having at least one light-transmitting region, the reticle being illuminated by the off-axis illumination light;
a projection optical system focusing projected light passing through the reticle;
a substrate stage moving in an optical axis direction of the projection optical system and a direction substantially perpendicular to the optical axis direction, the substrate stage having a substrate holder for holding a substrate;
a light sensor measuring an intensity of the projected light having at least one peak and variations of the intensity and the at least one peak in accordance with changes in a position of the substrate stage, the light sensor having a projection plane where the projected light is focused thereon; and
a focusing system for determining a focus position based on the variations of the intensity and the at least one peak. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification