Critical tool performance analysis for SCALPEL extensibility

Abstract

Electron and ion optical design software for integrated circuit manufacturing equipmentAn important feature of any advanced lithography technology is its cost-effective extension over several device generations beyond its introduction. Since SCALPEL is an electron imaging system with resolution not limited by diffraction, a unique extensibility analysis is needed to establish development pathways for the evolution of SCALPEL to the 50 nm generation and beyond. A combination of modest progress in four performance areas-effective optical field width, aberrations, acceptable dose latitude, and stage performance-will allow SCALPEL to maintain good throughput over several lithography generations without aggressive optical design scaling.

Determination of the possible magnitude of the charging effect in a SCALPEL mask membrane

“…͑A dark field mask has the advantage of reducing the space charge effects and making it less dependent on the pattern density. 12 ͒ For instance, in application-specific integrated circuits ͑ASICs͒, static random access memories ͑SRAMs͒, and dynamic random access memories ͑DRAMs͒ the pattern density is about 10%, 40%, and 45%, respectively, for the gate level, and about 5% for the contact hole level. This will correspond to less than 50% open area in a SCALPEL mask if a negative tone resist is used for printing gates and a positive tone resist for printing contact holes.…”