Advances in Optical and Magnetooptical Scatterometry of Periodically Ordered Nanostructured Arrays

Martin Veis,Roman Antos

doi:10.1155/2013/621531

Abstract

We review recent advances in optical and magnetooptical (MO) scatterometry applied to periodically ordered nanostructures such as periodically patterned lines, wires, dots, or holes. The techniques are based on spectroscopic ellipsometry (SE), either in the basic or generalized modes, Mueller matrix polarimetry, and MO spectroscopy mainly based on MO Kerr effect measurements. We briefly present experimental setups, commonly used theoretical approaches, and experimental results obtained by SE and MO spectroscopic analyses of various samples. The reviewed analyses are mainly related to monitoring optical critical dimensions such as the widths, depths, and periods of the patterned elements, their real shapes, and their line edge or linewidth roughness. We also discuss the advantages and disadvantages of the optical spectroscopic techniques compared to direct monitoring techniques.

Highlights

Recent advances in nanotechnologies [1, 2] have yielded periodically ordered nanostructures with shapes of unlimited complexity, ultrahigh depth and lateral resolution, high aspect ratios, and various material compositions, all of which require further development of characterization techniques
We review recent advances in optical and magnetooptical (MO) scatterometry applied to periodically ordered nanostructures such as periodically patterned lines, wires, dots, or holes. e techniques are based on spectroscopic ellipsometry (SE), either in the basic or generalized modes, Mueller matrix polarimetry, and MO spectroscopy mainly based on MO Kerr effect measurements
Optical scatterometry is most frequently based on SE and sometimes is combined with spectrophotometry. e SE spectra are almost always measured in the specular re ection, which corresponds to the zeroth order of the grating diffraction

Summary

Introduction

Recent advances in nanotechnologies [1, 2] have yielded periodically ordered nanostructures with shapes of unlimited complexity, ultrahigh depth and lateral resolution, high aspect ratios, and various material compositions, all of which require further development of characterization techniques. E direct techniques for monitoring the geometric properties of laterally patterned nanostructures are scanning electron microscopy (SEM) and scanning probe methods such as scanning tunneling microscopy (STM), restricted to samples with metallic surfaces, atomic force microscopy (AFM), or magnetic force microscopy (MFM), restricted to samples with magnetic surfaces These techniques have some disadvantages and restrictions (SEM requires cutting a sample to image its cross-section, while the scanning probe methods are affected by the probe-sample contact and special surfaces as mentioned), their recent development helped to overcome some of them. We include an example of AFM, SE, and MO investigation of a magnetic grating

Experimental Techniques

Theoretical Approaches

Results

Conclusions