File:EUV T2T aerial image.png

English: This is an illustration of the tip-to-tip imaging by conventional EUV lithography. With off-axis (dipole, quadrupole) illumination required for the dense linewidth, the gap between line-end tips is especially difficult to optimize.^[1] The gaps are generally imaged by conventional instead of off-axis illumination,^[2] though off-axis components are generally included. The light intensity is difficult to reduce in a region which is illuminated for maximum line intensity. Specifically, the gaps in the line-space pattern have relatively low weight of its diffraction pattern compared to that of the line-space pattern itself, leading to the potential for sidelobes in targeted dark areas.^[3] Targeting a smaller gap results in vanishing dose tolerance.