PREVAIL: Operation of the electron optics proof-of-concept system

Abstract

A proof-of-concept (POC) system was built to prove the electron optics concept of PREVAIL as a viable technology for next generation lithography (NGL), and is described elsewhere (H. C. Pfeiffer et al., J. Vac. Sci. Technology B, these proceedings; W. Stickel et al. ibid., these proceedings). The primary objective of the PREVAIL POC system is the embodiment of the curvilinear variable-axis lens (CVAL) optics which provides superior performance in terms of minimum geometric aberrations over unusually large deflection distances off the system axis (see Stickel et al.). Another major benefit of the CVAL is the minimization of the Coulomb interaction blur, since this approach permits the reduction of the column length to the smallest practical dimensions. The implementation of the PREVAIL CVAL requires a much higher degree of complexity than that of probe-forming systems, even of those which incorporate variable-axis immersion lenses [M. A. Sturans et al., J. Vac. Sci. Technol. B 8, 1682 (1990)] in the projection optics. The procedure used to establish the proper curvilinear variable-axis trajectory has required the development of hardware and software tools and is semiautomated. In this article we describe the means employed to properly establish the imaging conditions and the curvilinear trajectory of the deflected beam. Proper adjustment of the components is verified by comparison with the theoretically predicted excitation values for the deflection and axis-shifting yokes. Performance results presented by Pfeiffer et al. in terms of image blur and subfield distortion provide the proof of concept for the CVAL imaging conditions. © 1999 American Vacuum Society.