Limits of lithography

Lithography technology has been one of the key enablers and drivers for the semiconductor industry for the past several decades, Improvements in lithography are responsible for roughly half of the improvement in cost per function in integrated circuit (IC) technology The underlying reason for the driving force in semiconductor technology has been the ability to keep the cost for printing a silicon wafer roughly constant while dramatically increasing the number of transistors that can be printed per chip. ICs have al ways been printed optically with improvements in lens and imaging the steady improvement of lithography technology. The end material technology along with decreases in wavelength used fueling of optical lithography technology has been predicted by many and for many years. Many technologies have been proposed and developed to improve on the performance of optical lithography. but so far none has succeeded. This has been true largely because it has always been more economical to push incremental improvements in the existing optical technology rather than displace it with a new one. At so,nr point in time, the costs for pushing optical lithograph?, technology beyond previously conceived limits may exceed the cost of introducing new technologies. In this paper I examine the limits of lithography? and possible future technologies from both a technical al and economic point of view.