Device and Method for Transmission Image Sensing
AssigneeASML Netherlands B.V.
InventorBearrach MOEST
Life of this patent
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Abstract
A device for transmission image sensing for sensing an aerial image in a lithographic exposure apparatus comprises a projection system arranged to form, at an image side of the projection system, an aerial image of an object mark. The device further comprises a detector comprising a slit pattern having features corresponding to at least a part of the aerial image. The slit pattern is arranged to be exposed to the aerial image. The detector is further being arranged to detect detection radiation transmitted by the slit pattern; wherein d<0.85 λ/NA, where d represents the dimension of the smallest feature of the slit pattern, λ represents the intended wavelength of the detection radiation, and NA, which is larger than 1, represents the numerical aperture of the image side.
Claims21
A device for transmission image sensing for sensing an aerial image in a lithographic exposure apparatus, the device comprising:
- a projection system arranged to form, at an image side of the projection system, an aerial image of an object mark, the image side having a numerical aperture larger than 1, and the object mark having a first mark element in a first direction and a second mark element in a second direction, wherein the first direction and the second direction are orthogonal;
- and
- a detector comprising a first slit pattern and a second slit pattern, each having features arranged to correspond to at least a part of the aerial image, the first and second slit patterns being arranged to be exposed to the aerial image, the detector further being arranged to detect detection radiation transmitted by the first and second slit patterns.
A method for transmission image sensing of an aerial image comprising:
- providing detection radiation;
- using a projection system and the detection radiation to form on an image side of the projection system an aerial image of an object mark, the image side having a numerical aperture larger than 1, and the object mark having a first mark element in a first direction and a second mark element in a second direction, wherein the first direction and the second direction are orthogonal;
- exposing a first and second slit pattern to the aerial image, the first and second slit patterns each having features corresponding to at least a part of the aerial image;
- and
- detecting the detection radiation transmitted by the first and second slit patterns.
Dependencies are inferred from the claim text.