First steps towards a scatterometry reference standard

Abstract

Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has recently started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology and to establish scatterometry as a traceable and absolute metrological method for dimensional measurements. This requires a thorough investigation of the influence of all significant sample, tool and data analysis parameters, which affect the scatterometric measurement results. For this purpose and to improve the tool matching between scatterometers, CD-SEMs and CD-AFMs, experimental and modelling methods will be enhanced. The different scatterometry methods will be compared with each other and with specially adapted atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurement systems. Additionally novel methods for sophisticated data analysis will be developed and investigated to reach significant reductions of the measurement uncertainties in critical dimension (CD) metrology. To transfer traceability to industrial applications of scatterometry an important step and one final goal of this project is the realisation of different waferbased reference standard materials for calibration of scatterometers. The approaches to reach these goals and first design considerations and preliminary specification of the scatterometry standards are presented and discussed.

Methods for optical modeling and cross-checking in ellipsometry and scatterometry

“…It means that the method has to be traceable to a reference standard. 66 Although a reference standard is a stable and highly reproducible structure, 67 it is suitable for validation only when measured and cross-checked with other reference methods. 66 As a primary aim, it is also crucial to achieve accurate optical measurements at the industrial level.…”

Hp-finite element method for simulating light scattering from complex 3D structures

“…In previous contributions these have been applied to various setups in optical metrology. [8][9][10][11][12][13][14][15] In this context, also 3D structures have been investigated. [16][17][18][19] Here we discuss methods for further performance improvements, especially for efficient simulation of 3D devices with complex geometries.…”

Hp-finite-elements for simulating electromagnetic fields in optical devices with rough textures

“…Recently, our FEM Maxwell solver (JCMsuite) has been applied for various tasks in optics design. Among these are the design of microstructured fibers, 6, 7 solar cells, 8 microlithography masks, 9 integrated microlenses, 10 metamaterials, 11 microcavities, 12,13 plasmonic waveguides, 14 scatterometry reference standards, 15 and others. 16 Here, we discuss a method for improvement of numerical performance, so-called hp-FEM.…”