Lithographic apparatus, device manufacturing methods, mask and method of characterizing a mask and/or pellicle
First Claim
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1. A lithographic projection apparatus comprising:
- an illumination system configured to supply a beam of radiation;
a support structure configured to support a patterning device, the patterning device serving to pattern the beam of radiation according to a desired pattern to form a patterned beam of radiation;
a substrate table configured to hold a substrate;
a projection system configured to project the patterned beam of radiation onto a target portion of the substrate;
a layer, substantially transparent to the beam of radiation but having a refractive index different than the surrounding medium, in the optical path of the beam of radiation between the patterning device and the substrate;
a storage device adapted to store information relating to the physical and/or optical characteristics of the layer; and
a controller adapted to control at least one of the projection system, the illumination system, the substrate table and the support structure in response to information stored in the storage device to compensate for imaging aberrations caused by the layer other than a displacement of an apparent patterning device position along an optical axis of the apparatus.
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Abstract
A thick pellicle is allowed to have a non-flat shape and its shape is characterized to calculate corrections to be applied in exposures to compensate for the optical effects of the pellicle. The pellicle may be mounted so as to adopt a one-dimensional shape under the influence of gravity to make the compensation easier.
26 Citations
22 Claims
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1. A lithographic projection apparatus comprising:
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an illumination system configured to supply a beam of radiation; a support structure configured to support a patterning device, the patterning device serving to pattern the beam of radiation according to a desired pattern to form a patterned beam of radiation; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam of radiation onto a target portion of the substrate; a layer, substantially transparent to the beam of radiation but having a refractive index different than the surrounding medium, in the optical path of the beam of radiation between the patterning device and the substrate; a storage device adapted to store information relating to the physical and/or optical characteristics of the layer; and a controller adapted to control at least one of the projection system, the illumination system, the substrate table and the support structure in response to information stored in the storage device to compensate for imaging aberrations caused by the layer other than a displacement of an apparent patterning device position along an optical axis of the apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of attaching a pellicle to a mask, comprising:
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measuring the shape of the pellicle; determining an optimum position of the pellicle relative to the mask; and attaching the pellicle to the mask substantially at the optimum position. - View Dependent Claims (13, 14)
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15. A method comprising:
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loading a mask into a lithographic projection apparatus; illuminating the mask with exposure radiation; projecting an aerial image of the illuminated mask; and measuring a plane of best focus of images of a plurality of alignment marks using an image sensor; wherein the plurality of alignment marks are spaced apart in a scanning direction or a direction of an illumination field of the lithographic apparatus. - View Dependent Claims (16)
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17. A device manufacturing method comprising:
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patterning a beam of radiation with a pattern in its cross-section using a mask having a pellicle or fixed relation thereto; projecting the patterned beam of radiation onto a target portion of a layer of radiation-sensitive material on a substrate; and prior to an exposure, characterizing a shape of the mask by; measuring a shape of the pellicle; determining an optimum position of the pellicle relative to the mask; attaching the pellicle to the mask substantially at the optimum position; and correcting exposure parameters based on the characterizing. - View Dependent Claims (18, 19)
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20. A device manufacturing method comprising:
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patterning a beam of radiation with a pattern in its cross-section using a mask having a pellicle or fixed relation thereto; projecting the patterned beam of radiation onto a target portion of a layer of radiation-sensitive material on a substrate; and prior to an exposure, characterizing a shape of the mask by; measuring a shape of the pellicle; determining an optimum position of the pellicle relative to the mask; attaching the pellicle to the mask substantially at the optimum position; and correcting parameters pertaining to at least one of a radiation system, a projection system, a position of the mask and a position of the substrate to compensate for aberrations other than a shift in apparent position of the mask in the direction of the optical axis of the projection system caused by the pellicle, the corrections having been determined from information relating to physical and/or optical characteristics of the pellicle. - View Dependent Claims (21, 22)
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Specification