Feature-size Control by Pattern Transfer Etching in Nanoimprint Lithography for Half-pitch 24 nm Damascene Interconnect

Nanoimprint lithography (NIL) is a promising technique for fabricating dual damascene structures commonly fabricated in back-end-of-line layers. The feature size must be controlled for forming good open/short interconnects in damascene processes. In this work, we controlled the feature size by pattern transfer etching in NIL for half-pitch (HP) 24 nm damascene interconnects. By changing the conditions when transferring patterns etched in NIL to spin-on-carbon layers, the wiring dimensions were changed by approximately 5 nm for a HP 24 nm. A test pattern was fabricated by depositing tungsten, followed by chemical mechanical polishing. The electrical characteristics of test devices were subsequently evaluated using the open/short test element group. We widened the process window for fabricating damascene interconnects by varying the linewidth to control the feature size in pattern transfer etching.