| 摘要 |
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.
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