Extendibility of x-ray lithography to ⩽130 nm ground rules in complex integrated circuit patterns

Abstract

Articles you may be interested in X-ray mask fabrication technology for 0.1 μm very large scale integrated circuits Extendibility of synchrotron radiation lithography to the sub-100 nm region Previous experimental and theoretical evidence indicates that x-ray lithography can be used to pattern р180 nm features. In order to be used in manufacturing, x-ray lithography of complex integrated circuit patterns ͑i.e., dense two-dimensional patterns͒ needs to be demonstrated with a practical proximity gap. However, no large body of experimental evidence exists for the extendibility of x-ray lithography for complex patterns with ground rules of р130 nm at gaps of 10-20 m. Simulations of image formation and resist dissolution are shown to have good agreement with experimental results. These simulations are then used to predict exposure latitude and gap latitude for printing one-dimensional 75-125 nm patterns at 10-15 m gaps. Simulations indicate that at least Ϯ10% exposure dose latitude will exist for simple patterns at these gaps, but significant nested-to-isolated linewidth bias will exist. Gaps must be controlled to Ϯ1 m for Ϯ10% dose latitude. More complex two-dimensional patterns have been shown to exhibit line end shortening ͓J. Maldonado, R. Dellaguardia, S. Hector, M. McCord, and L. Liebmann, J. Vac. Sci. Technol. B 13, 3094 ͑1995͔͒ that simulations qualitatively indicate a rise in part due to image formation. Simple serifs on line ends may be needed to reduce line end shortening.

X-ray lithography: Status, challenges, and outlook for 0.13 μm

“…3, a 5 m change of gap results in a change in linewidth of ϳ10-15 nm for isolated features and an even smaller one for nested features ͑i.e., ⌬LW/⌬gϳ2 nm/m͒, which translates into ϳ1 nm for the present gap control capability believed to be ϳ0.5 m. The bias between nested and isolated features has been found to depend on the mask-to-wafer gap as well as the feature size; it is generally in good agreement with modeling. 30,31 The large latitude and smooth characteristic of the variation of linewidth with dose allow the use of dose tailoring to obtain optimized printing and sub-100 nm features, as illustrated in Fig. 4͑a͒, where the resist was intentionally overexposed to print features smaller than the 120 nm features on the mask.…”