Abstract: A sensor for use at substrate level in a high numerical aperature lithographic apparatus, the sensor having a transparent plate that covers a sensing element and includes elements that improve coupling of radiation into the sensing element. The elements include Fresnel lenses, holographic optical elements, inverted Winston Cones, spherical lenses and surface roughening.

Abstract: A method and apparatus make use of data representing changes in wavelength of a radiation source to provide control of focal plane position or to provide correction of sensor data. In the first aspect, the wavelength variation data is provided to control systems that control focus by moving apparatus components including, for example, the mask table, the substrate table or optical elements of the projection optical system. In the second aspect, variation data is used in correcting, e.g., focal plane position data measured by an inboard sensor, such as a transmitted image sensor. The two aspects may be combined in a single apparatus or may be used separately.

Abstract: A sensor for use at substrate level in a high numerical aperature lithographic apparatus, the sensor having a transparent plate that covers a sensing element and includes elements that improve coupling of radiation into the sensing element. The elements include Fresnel lenses, holographic optical elements, inverted Winston Cones, spherical lenses and surface roughening.