Abstract

Lithography capabilities and requirements for the formation of submicrometer features are reviewed. The capabilities are related to the performance characteristics of the optical systems: wavelength and numerical aperture, which determine minimum critical-feature size and depth of focus; and the intensity (energy deposited perunittime) and speed of registration, which partially determine throughput. Commercial acceptance criteria include wafer throughput for a given cost rate and the yield and utilization that the equipment affords. Cost of entry and facility transparency are also significant issues. Current g- and i-line systems are capable of producing dimensions as small as 0.8 and 0.6μm. The ability to extend i-line systems to fabricate critical features as small as 0.5 μm with limited depth of focus is considered. Deep ultraviolet (DUV) 248 nm systems in development demonstrate feature sizes as small as 0.4 μm. Both sharp-line sources and broadband systems are in advanced states of development. Approaches for deep-submicrometer systems include extensions of DUV systems to shorter wavelengths, x rays, and even electron or ion beams. The relative advantages and limiting issues of such systems will be discussed. Many breakthroughs, such as source, resist, and registration capability, are required before a preferred path for deep-submicrometer systems can be selected and commercialized. Technical and economic requirements will be summarized.

© 1990 Optical Society of America