Continued refinement of optical projection lithography has enabled the semiconductor industry to steadily reduce IC design rules. Increasing the numerical aperture of the projection lens, modifying the illumination of the mask, adding additional and phase shifting features to the mask pattern, and reducing the wavelength of the light have enabled continual improvements in resolution. Optical lithography will continue to be used for manufacturing down to 130 nm using 248 and 193 nm wavelengths. In fact, 193 nm exposure tools might even extend optical lithography to 100 nm resolution, which is nearly half of the wavelength. A shorter wavelength than 193 nm or a next generation lithography approach will be required at or below 100 nm. Changing the wavelength to 157 nm introduces significant new challenges that will be outlined in this presentation. Because of the difficulty of using 157 nm light and because of the shrinking process latitude of optical lithography, non-optical lithography techniques are likely to be introduced for <100 nm patterning. Significant progress has been made in recent years to develop extreme ultraviolet lithography (EUVL) and electron projection lithography (EPL) technologies. However, significant technical challenges exist in bringing either or both technologies into high volume IC manufacturing.