Phase-structured illumination as a tool to detect nanometer asymmetries

Abstract. Phase-structured illumination is investigated as a possible extension of scatterometric measurement methods for silicon line gratings. This is done by means of rigorous simulations. Special emphasis is put on the capability of this approach to detect nanoscale fabrication asymmetries such as sidewall angles, bottom rounding, and floor tilt. The studied setup features a focused spot (numerical aperture=0.7), i.e., scanned over the sample, while analyzing the phase distribution in the image plane. This phase distribution can be accessed via holographic imaging. The results are compared to conventional nonstructured illumination. It is shown that by employing phase structuring, the resulting phase changes are larger, even if only symmetric deviations are considered. For asymmetric deviations, phase-structured illumination provides much higher sensitivity and better capability to detect the sign of the asymmetry.

[1]  Bernd Bodermann,et al.  Investigations of the influence of common approximations in scatterometry for dimensional nanometrology , 2014 .

[2]  S. Chou,et al.  Imprint Lithography with 25-Nanometer Resolution , 1996, Science.

[3]  Bryan M. Barnes,et al.  193 nm angle-resolved scatterfield microscope for semiconductor metrology , 2009, NanoScience + Engineering.

[4]  Hui Zhou,et al.  Three-dimensional deep sub-wavelength defect detection using λ = 193 nm optical microscopy. , 2013, Optics express.

[5]  S. Roy,et al.  Phase retrieval between overlapping orders in coherent Fourier scatterometry using scanning , 2013 .

[6]  Michael Atlan,et al.  Digital Holography at Shot Noise Level , 2010, Journal of Display Technology.

[7]  Jan Liesener,et al.  Model-based white light interference microscopy for metrology of transparent film stacks and optically-unresolved structures , 2009 .

[8]  C. Raymond,et al.  Scatterometry for Semiconductor Metrology , 2001 .

[9]  Wolfgang Osten,et al.  Solving the inverse grating problem by white light interference Fourier scatterometry , 2012, Light: Science & Applications.

[10]  Wolfgang Osten,et al.  Phase-sensitive structured illumination to detect nanosized asymmetries in silicon trenches , 2015 .

[11]  Simon Ward,et al.  Comparison of solutions to the scatterometry inverse problem , 2004, SPIE Advanced Lithography.

[12]  Michiel Kupers,et al.  Non-linear methods for overlay control , 2007, SPIE Advanced Lithography.

[13]  Hao Jiang,et al.  Mueller matrix ellipsometric detection of profile asymmetry in nanoimprinted grating structures , 2014 .

[14]  Jan Mulkens,et al.  Holistic optimization architecture enabling sub-14-nm projection lithography , 2014 .

[15]  Wolfgang Osten,et al.  High-resolution quantitative phase microscopic imaging in deep UV with phase retrieval. , 2011, Optics letters.

[16]  Chandraprakash Chindam.  Fourier Modal Method and Its Applications in Computational Nanophotonics , 2012 .

[17]  S. Chou,et al.  Sub-10 nm imprint lithography and applications , 1997 .

[18]  Jan Richter,et al.  Deep ultraviolet scatterometer for dimensional characterization of nanostructures: system improvements and test measurements , 2011 .

[19]  Hans J. Tiziani,et al.  Vector simulations of dark beam interaction with nanoscale surface features , 2003, SPIE Optical Metrology.

[20]  H. P. Urbach,et al.  Measurement comparison of goniometric scatterometry and coherent Fourier scatterometry , 2014, Photonics Europe.

[21]  M. Atlan,et al.  Digital holography with ultimate sensitivity. , 2008, Optics letters.

[22]  M. Totzeck,et al.  Numerical simulation of high-NA quantitative polarization microscopy and corresponding near-fields , 2001 .

[23]  Lijiang Zeng,et al.  Scatterometry specialized for a highly asymmetric triangular grating on a transparent substrate. , 2014, Applied Optics.

[24]  Wolfgang Osten,et al.  Detection of overlay error in double patterning gratings using phase-structured illumination. , 2015, Optics express.

[25]  T. Novikova,et al.  Mueller polarimetry as a tool for detecting asymmetry in diffraction grating profiles , 2011 .