Immersion's evolution launches the age of hyper-NA lithography

摘要

Immersion arrived on the lithography roadmap shortly after the first immersion images became available in the fall of 2003. In addition to enabling a > 50% increase in depth of focus (DOF) over dry lithography, immersion also offers increased critical dimension (CD) control, as well as the potential for mask and process simplification because of the larger DOF budget. With polarized illumination, the resolution limit for 0.93NA immersion systems has been extended to the 55nm half-pitch and, besides enlarged DOF, the water between the lens and the wafer enables the jump to lens designs having an NA > 1.