Extreme ultraviolet (EUV) lithography is seen as a main candidate for production of future generation computer
technology. Due to the short wavelength of EUV light (≈ 13 nm) novel reflective masks have to be used in the
production process. A prerequisite to meet the high quality requirements for these EUV masks is a simple and
accurate method for absorber pattern profile characterization.
In our previous work we demonstrated that the Finite Element Method (FEM) is very well suited for the simulation
of EUV scatterometry and can be used to reconstruct EUV mask profiles from experimental scatterometric
In this contribution we apply an indirect metrology method to periodic EUV line masks with different critical
dimensions (140 nm and 540 nm) over a large range of duty cycles (1:2, ... , 1:20). We quantitatively compare
the reconstructed absorber pattern parameters to values obtained from direct AFM and CD-SEM measurements.
We analyze the reliability of the reconstruction for the given experimental data. For the CD of the absorber
lines, the comparison shows agreement of the order of 1nm.
Furthermore we discuss special numerical techniques like domain decomposition algorithms and high order
finite elements and their importance for fast and accurate solution of the inverse problem.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.