Investigation of Full-Field CD Control of Sub-100 nm Gate Features by Phase-shift 248-nm Lithography

摘要

Achieving CD control for sub-100 nm processes will be challenging due to the low-k1 regime that optical patterning approaches will be required to work in. New challenges are expected to arise related to new lithography tools, photoresists, reticle types, and in some cases multiple exposures per layer. This work examines the intra- field CD variations for a range of sub-100nm resist features patterned by chromeless phase-shift 249-nm lithography. One significant advantage of this patterning technique is that the resist CD's are a function of the exposure dose. This provides the ability to examine the CD variations of a range of linewidths in a single experiment without relying on reticle pattern scaling to determine the lindwidth printed on the wafer. In addition to exploring CD control vs feature size, we also examine the full-field depth of focus for these features.