7 - Electron-Beam ULSI Applications

Abstract

This chapter provides an overview of electron-beam ULSI applications. Electron-beam lithography is a technology for the transfer of computer aided design pattern data from a digitally stored format to a high-resolution spatial reality on a nominally flat substrate. Its main characteristics are high resolution, due in part to the short electron wavelength, and flexibility, due to the easily modified pattern source. The suitability of the overall lithographic process for the ultimate pattern transfer step is essential for a viable lithographic process. The most common application for electron-beam lithography is in the fabrication of masks and reticles used for projection optical lithography. For this application, the electron-beam lithography process generates the master mask primarily in a serial manner. This mask is subsequently used in projection optical lithography equipment (steppers) to replicate the mask pattern directly onto resist-coated substrates in a parallel manner. The electron-beam lithography process is highly suitable for mask fabrication and provides sufficient resolution for increasingly demanding mask requirements, such as optical proximity correction, phase shifting, and 1X magnification x-ray masks.