Exploring the temperature effect on line-scan profile of a pitch structure under electron irradiation

Abstract

Scanning electron microscope (SEM) is widely used in imaging rather than for thermometry. In this work, the temperature-dependent line-scan profile for a silicon (Si) pitch structure was investigated by a simulation approach. Various electron signals (secondary electron (SE) and backscattering electron (BSE)) were recorded with different values of temperature at various primary electron (PE) energies. It is found that both the SE and BSE line-scan profiles vary with the temperature. However, the BSE line-scan profile presents a lower contrast than that of the SE profile. The deposited energies contributed by full electrons, Pes, and cascaded electrons as functions of depth and radial direction at different temperatures for this pitch structure were also investigated. It was concluded that the influences of the temperature of a solid on the scattering processes of PEs and cascaded electrons are different. Possible mechanisms were systematically analyzed based on the theory of electron–solid interaction. Finally, the temperature effect on the pitch measurement based on a line-scan profile was also investigated through the maximum derivative method. It was found that the bias value slightly increases with temperature. This work poses a potential possibility of measuring the temperature of nanostructures by acquiring the temperature-dependent line-scan profile by a standard SEM.