A Monte Carlo Model for SEM Linewidth Metrology

Published

May 1, 1994

Author(s)

J R. Lowney, Michael T. Postek, Andras Vladar

Abstract

A scanning electron microscope (SEM) can be used to measure the dimensions of the microlithographic features of integrated circuits. However, without a good model of the electron-beam / specimen interaction, accurate edge location cannot be obtained. A Monte Carlo code has been developed to model the interaction of an electron beam with a line lithographically produced on a multi-layer substrate. The purpose of the code is to enable one to extract the edge position of a line from SEM measurements. It is based on prior codes developed at NIST, but with a new formulation for the atomic scattering cross sections and the inclusion of a method to simulate edge roughness or founding. The code is currently able to model the transmitted and backscattered electrons, and the results from the code have been applied to the analysis of electron transmission through a gold line on a thin silicon substrate, such as used in an X?ray lithographic mask. By comparing the predictions of the code with measured data, it is possible to obtain edge positions to the order of +/-10 nm, which is needed for the advanced lithography projected for the year 2000. The uncertainty of this measurement is limited by the sample geometry and surface roughness and not by the measurement process.

Proceedings Title

Proceedings of SPIE, Integrated Circuit Metrology, Inspection, and Process Control VIII, Marylyn H. Bennett, Editor

Volume

2196

Conference Dates

March 2, 1994

Conference Location

San Jose, CA, USA

Conference Title

SEM Metrology I

Pub Type

Conferences

Citation

Lowney, J. , Postek, M. and Vladar, A. (1994), A Monte Carlo Model for SEM Linewidth Metrology, Proceedings of SPIE, Integrated Circuit Metrology, Inspection, and Process Control VIII, Marylyn H. Bennett, Editor, San Jose, CA, USA (Accessed April 25, 2024)