This paper is an overview of work in the IBM Microelectronics Division to e
xtend electron-beam lithography technology to the projection level for use
in next-generation lithography. The approach being explored-Projection Redu
ction Exposure with Variable Axis Immersion Lenses (PREVAIL)-combines the h
igh exposure efficiency of massively parallel pixel projection with scannin
g-probe-forming systems to dynamically correct for aberrations. In contrast
to optical lithography systems, electron-beam lithography systems are not
diffraction-limited, and their ultimate attainable resolution is, for pract
ical purposes, unlimited. However, their throughput has been-and continues
to be-the major challenge in electron-beam lithography. The work described
here, currently continuing, has been undertaken to address that challenge.
Novel electron optical methods have been used and their feasibility ascerta
ined by means of a Proof-Of-Concept (POC) system containing a Curvilinear V
ariable Axis Lens (CVAL) for achieving large-distance (> 20 mm at a reticle
) beam scanning at a resolution of < 100 nm, and a high-emittance electron
source for achieving uniform illumination of a 1-mm(2) section of the retic
le. A production-level prototype PREVAIL system, an "alpha" system, for the
100-nm node has been under development jointly with the Nikon Corporation.
At the writing of this paper, its electron-optics subsystem had been broug
ht up to basic operation and was being prepared for integration with its me
chanical and vacuum subsystem, under development at Nikon facilities.