Abstract: In a projection system a pattern plane on a reticle is illuminated to have a projection image focussed on an image plane. The presence of a pellicle in the optical path causes a virtual shift of the position of the pattern plane on the reticle. Depending on the presence or absence of the pellicle the image plane of the projection image needs to be adapted for proper focussing. A compensator counteracts the virtual shift of pattern plane due to the pellicle, by shifting the position of the pattern plane.

Abstract: A method is provided for compensating for the effect of flare lithographic apparatus. The method includes establishing a power spectral density (PSD) indicative of the spatial frequency of the stray radiation produced by a projection system, and determining, from the PSD, a modulation transfer function (MTF) relating the PSD to a pattern applied by a patterning device to take the effect of flare on the pattern image into account. The MTF is then used to determine the effect of flare on a critical dimension (CD) of the pattern image, and a relationship is established between any change in the CD of the pattern image and a change in the CD of the pattern. The patterning device may then be designed in such a way as to at least partially offset the effect of flare on the CD of the pattern image.

Abstract: A method is provided to reduce differences between the way in which reticle chucking forces and gravity force act upon the reticle during use and during assembly of the pellicle, and to combine this with a similar reduction concerning pellicle chucking forces and gravity force acting upon the pellicle during bonding to the reticle and during quality control of the pellicle. The shape of the pellicle is measured for control in the same orientation of the pellicle with respect to gravity force as during use of the pellicle, and during bonding the pellicle and the reticle are held in the same way and in the same orientation as during control of the pellicle and use of the reticle in the lithographic apparatus, respectively.

Abstract: In a projection system a pattern plane on a reticle is illuminated to have a projection image focussed on an image plane. The presence of a pellicle in the optical path causes a virtual shift of the position of the pattern plane on the reticle. Depending on the presence or absence of the pellicle the image plane of the projection image needs to be adapted for proper focussing. A compensator counteracts the virtual shift of pattern plane due to the pellicle, by shifting the position of the pattern plane.