Projection exposure apparatus
AssigneeNikon Corporation
InventorTetsuo Taniguchi
Life of this patent
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Abstract
A transparent correcting plate is disposed between a reticle and a projection optical system. The correcting plate can be selectively inserted and withdrawn by a changing device. The correcting plate can be changed for another correcting plate stored in a storage unit according to need. The correcting plate has been polished so as to be capable of correcting random distortion, and thus it corrects random distortion produced by a projection exposure apparatus in which it is used. Further, a correcting plate is selected according to image distortion characteristics of a projection exposure apparatus used in the preceding exposure process or a projection exposure apparatus to be used in the subsequent process, thereby correcting the distortion of a projected image, and thus improving the overlay accuracy between two layers.
Claims29
An exposure apparatus which exposes a second object with an energy beam irradiated on a first object, comprising:
- an illumination optical system disposed on an optical pass through which the energy beam passes to illuminate the first object with the energy beam;
- a projection optical system of which a movable optical element is arranged along an optical axis thereof to project the energy beam from the first object onto the second object;
- an actuator installed within the projection optical system to adjust symmetrical distortion of the projection optical system by movement of the movable optical element;
- and
- an optical member provided between the first object and the movable optical element to correct asymmetrical distortion of the projection optical system.
A method for making an exposure apparatus in which a second object is exposed with an energy beam irradiated on a first object, comprising:
- providing an illumination optical system on an optical pass through which the energy beam passes to illuminate the first object with the energy beam;
- providing a projection optical system of which a movable optical element is arranged along an optical axis thereof to project the energy beam from the first object onto the second object;
- installing an actuator within the projection optical system to adjust symmetrical distortion of the projection optical system by movement of the movable optical element;
- and
- providing an optical member between the first object and the movable optical element to correct asymmetrical distortion of the projection optical system.
A method of exposing a second object through a projection optical system, with an energy beam irradiated on a first object, comprising:
- adjusting symmetrical distortion of the projection optical system by movement of a movable optical element installed within the projection optical system;
- and
- correcting by an optical member disposed between the first object and the movable optical element, asymmetrical distortion of the projection optical system.
An exposure apparatus wherein a pattern formed on a first object is projected onto a second object through a projection optical system, comprising:
- an optical member provided between said first object and said projection optical system to generate asymmetrical image distortion according to image distortion characteristics of another exposure apparatus used to carry out exposure for said second object;
- and
- an adjusting system, an actuator of which is installed within said projection optical system to move at least one optical element of said projection optical system, the adjusting system generating symmetrical image distortion according to the image distortion characteristics of said another exposure apparatus by moving the at least one optical element.
An exposure method in which patterns are overlaid on a substrate by using first and second exposure apparatus, comprising:
- disposing to said first exposure apparatus an optical member which generates change of asymmetrical pattern image according to an image-formation characteristic of said second exposure apparatus;
- moving at least one optical element of a projection optical system in said first exposure apparatus to generate a change in symmetrical pattern image according to the image-formation characteristics of said second exposure apparatus;
- and
- forming the changed pattern image on said substrate through said optical member and said projection optical system by using said first exposure apparatus.
An exposure apparatus which exposes a second object with an energy beam irradiated on a first object, comprising:
- a projection optical system, a plurality of optical elements of which are arranged along an optical axis thereof to project the energy beam from the first object onto the second object;
- an adjusting system, an actuator of which is installed within the projection optical system to adjust symmetrical aberration of the projection optical system by movement of at least one of the plurality of optical elements;
- and
- an optical member provided between the first object and the at least one optical element to correct asymmetrical aberration of the projection optical system.
Dependencies are inferred from the claim text.