Determination of secondary electron attenuation length to characterize electron blur (Conference Presentation)

Abstract

EUV photon absorption by a resist film leads to emission of a photoelectron and several low kinetic energy secondary electrons. The “universal curve”, used in X-ray photoelectron spectroscopy, suggests that the low kinetic energy electrons may travel tens to hundreds of nanometers in solids until they inelastically scatter. The fact that electrons travel long distances before they may initiate chemical reactions ultimately result in blur of the aerial image, reducing the contrast and subsequently resolution of the resist. In this work, we will present an experimental approach to determine secondary electron attenuation length (EAL) – the thickness of resist material required to reduce number of emitted secondary electrons to 1/e of initial. The EAL describes how far secondary electrons can travel in a resist film and is directly related to the electron blur. Possibilities to gain additional information on electron penetration depth in resist films will also be discussed.