J A Liddle

Publications (11)9.92 Total impact

• Chapter: Nano-Scale Imaging With Tabletop Soft X-Ray Lasers: Sub-38 nm Resolution

  C. S. Menoni, G. Vaschenko, F. Brizuela, C. Brewer, Y. Wang, M. A. Larotonda, B. M. Luther, M. C. Marconi, J. J. Rocca, W. Chao, J. A. Liddle, Y. Liu, E. H. Anderson, D. T. Attwood, A. V. Vinogradov, I. A. Artioukov, Y. P. Pershyn, V. V. Kondratenko
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  ABSTRACT: We report the demonstration of soft x-ray microscopes with resolution down to sub-38 nm using tabletop soft x-ray laser illumination. One of the compact microscopes combines the 46.9 nm wavelength output from a capillary discharge Ne-like Ar laser with a reflective condenser and a free standing zone plate objective. High quality images were acquired with this microscope in transmission mode and reflection mode. The latter includes images of an integrated circuit pattern containing polysilicon features on silicon. The spatial resolution for this microscope is between 120-150 nm. Increased resolution was demonstrated in another microscope using 13.2/13.9 nm wavelength illumination from Ni-like Cd/Ag transient soft x-ray lasers in combination with diffractive zone plate optics for both the condenser and objective. Using an objective zone plate with a 50 nm outer zone width, this optical system achieved a record sub-38 nm spatial resolution. These results demonstrate the feasibility of using compact high repetition rate soft-x-ray laser sources in nanometer-scale microscopy.
  12/2006: pages 417-425;
• Conference Proceeding: Nanometer-scale resolution microscopy with compact extreme ultraviolet lasers

  C. S. Menoni, G. Vaschenko, F. Brizuela, C. Brewer, Y. Wang, M. A. Larotonda, B. M. Luther, M. C. Marconi, J. J. Rocca, W. Chao, J. A. Liddle, Y. Liu, E. H. Anderson, D. T. Attwood, A. V. Vinogradov, I. A. Artioukov, Y. P. Pershyn, V. V. Kondratenko
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  ABSTRACT: In this paper, we have demonstrated nanoscale resolution microscopy in transmission and reflection modes using the lambda=46.9 nm and lambda=13 nm wavelength output from table-top EUV lasers. This compact microscope acquires high quality images in transmission and reflection modes in tens of seconds. Its spatial resolution has been determined to be 120-150 nm
  Lasers and Electro-Optics Society, 2006. LEOS 2006. 19th Annual Meeting of the IEEE; 11/2006
• Source

  Available from: colostate.edu

  Article: Sub-38 nm resolution tabletop microscopy with 13 nm wavelength laser light.

  G Vaschenko, C Brewer, F Brizuela, Y Wang, M A Larotonda, B M Luther, M C Marconi, J J Rocca, C S Menoni, E H Anderson, W Chao, B D Harteneck, J A Liddle, Y Liu, D T Attwood
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  ABSTRACT: We have acquired images with a spatial resolution better than 38 nm by using a tabletop microscope that combines 13 nm wavelength light from a high-brightness tabletop laser and Fresnel zone plate optics. These results open a gateway to the development of compact and widely available extreme-ultraviolet imaging tools capable of inspecting samples in a variety of environments with a 15-20 nm spatial resolution and a picosecond time resolution.
  Optics Letters 06/2006; 31(9):1214-6. · 3.40 Impact Factor
• Article: A silicon-based, sequential coat-and-etch process to fabricate nearly perfect substrate surfaces.

  P B Mirkarimi, E Spiller, S L Baker, D G Stearns, J C Robinson, D L Olynick, F Salmassi, J A Liddle, T Liang, A R Stivers
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  ABSTRACT: For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to approximately 70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize approximately 70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of approximately 470 degrees from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize approximately 70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface.
  Journal of Nanoscience and Nanotechnology 02/2006; 6(1):28-35. · 1.56 Impact Factor
• Article: A Silicon-Based, Sequential Coat-and-Etch Process to Fabricate Nearly Perfect Substrate Surfaces

  P.B. Mirkarimi, E. Spiller, S.L. Baker, D.G. Stearns, J.C. Robinson, D.L. Olynick, F. Salmassi, J.A. Liddle, T. Liang, A.R. Stivers
  [show abstract] [hide abstract]
  ABSTRACT: For many thin-film applications substrate imperfections such as particles, pits, scratches, and general roughness, can nucleate film defects which can severely detract from the coating's performance. Previously we developed a coat-and-etch process, termed the ion beam thin film planarization process, to planarize substrate particles up to ∼70 nm in diameter. The process relied on normal incidence etching; however, such a process induces defects nucleated by substrate pits to grow much larger. We have since developed a coat-and-etch process to planarize ∼70 nm deep by 70 nm wide substrate pits; it relies on etching at an off-normal incidence angle, i.e., an angle of ∼70° from the substrate normal. However, a disadvantage of this pit smoothing process is that it induces defects nucleated by substrate particles to grow larger. Combining elements from both processes we have been able to develop a silicon-based, coat-and-etch process to successfully planarize ∼70 nm substrate particles and pits simultaneously to at or below 1 nm in height; this value is important for applications such as extreme ultraviolet lithography (EUVL) masks. The coat-and-etch process has an added ability to significantly reduce high-spatial frequency roughness, rendering a nearly perfect substrate surface.
  Journal of Nanoscience and Nanotechnology 12/2005; 6(1):28-35. · 1.56 Impact Factor
• Source

  Available from: Igor Artyukov

  Article: Nanoimaging with a compact extreme-ultraviolet laser.

  G Vaschenko, F Brizuela, C Brewer, M Grisham, H Mancini, C S Menoni, M C Marconi, J J Rocca, W Chao, J A Liddle, E H Anderson, D T Attwood, A V Vinogradov, I A Artioukov, Y P Pershyn, V V Kondratenko
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  ABSTRACT: Images with a spatial resolution of 120-150 nm were obtained with 46.9 nm light from a compact capillary-discharge laser by use of the combination of a Sc-Si multilayer-coated Schwarzschild condenser and a free-standing imaging zone plate. The results are relevant to the development of compact extreme-ultraviolet laser-based imaging tools for nanoscience and nanotechnology.
  Optics Letters 09/2005; 30(16):2095-7. · 3.40 Impact Factor
• Article: Microlithography 2005

  G. Vaschenko, F. Brizuela, C. Brewer, M. Grisham, Y. Wang, M. A. Larotonda, B. M. Luther, C. S. Menoni, M. Marconi, J. J. Rocca, W. L. Chao, J. A. Liddle, E. H. Anderson, D. T. Attwood, A. V. Vinogradov, I. A. Artioukov, Y. P. Pershyn, V. V. Kondratenko
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  ABSTRACT: We report high resolution imaging results obtained utilizing small-scale extreme ultraviolet laser sources. A compact capillary-discharge pumped Ne-like Ar laser emitting at a wavelength of 46.9 nm was used to demonstrate imaging with nanometer-scale resolution in transmission and reflection modes. We exploited the large photon fluence of this short wavelength laser to obtain high-resolution images with exposure times as short as 1-10 seconds. Images with a spatial resolution better than 140 nm were obtained using the combination of a Sc/Si multilayer coated Schwarzschild condenser and free-standing objective zone plate. Preliminary results of imaging with a 13.9 nm extreme ultraviolet laser light are also discussed.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
  05/2005;
• Conference Proceeding: Soft X-ray microscopy and EUV lithography: imaging in the 20-40 nm regime

  D. Attwood, E. Anderson, W. Chao, G. Denbeaux, P. Fischer, K. Goldberg, J.A. Liddle, P. Naulleau, G. Schneider, J. Goldsmith, G. Kubiak, J. Taylor, D. Sweeney
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  ABSTRACT: Soft X-ray microscopy for the physical and life sciences, at wavelengths from 0.6 to 4 nm, and resolved to 20 nm, and EUV lithography at 13.5 nm wavelength, with printed features to 39 nm, are reviewed.
  Lasers and Electro-Optics Society, 2003. LEOS 2003. The 16th Annual Meeting of the IEEE; 11/2003
• Conference Proceeding: New demonstration technique of 20 nm spatial resolution soft X-ray microscopy

  W Chao, E Anderson, G. Denbeaux, B Harteneck, J A Liddle, D Olynick, A.L. Pearson, F. Salmassi, C. Song, D Attwood
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  ABSTRACT: This study deals with a new demonstration technique of full-field transmission soft X-ray imaging microscopy. The microscope's resolution is measured by utilizing a new type of test patterns, by the use of multilayer coatings. Processed with conventional TEM sample preparation technique, the cross sections of the coatings can be thinned to be sufficiently transparent for imaging in the microscope. Resolution measurements are done by using test patterns which consist of forty chromium/silicon bilayer pairs, with measured periods of 39.0 nm and 48.6 nm. At the half-periods of 19.5 nm and 24.3 nm, the modulations measured from the lineouts are 20% and 75%, respectively. A straight-line approximation between the measured points indicate that the microscope achieves the 26.5% modulation at a half-period of 20 nm. The calculated resolution, based on evaluation of the Hopkins theory of partially coherent imaging, is 19 nm. The microscope is thus 1.1× diffraction limited at λ = 2.07 nm.
  Lasers and Electro-Optics Society, 2003. LEOS 2003. The 16th Annual Meeting of the IEEE; 11/2003
• Article: Sub-pixel alignment for direct-write electron beam lithography

  E.H. Anderson, D. Ha, J.A. Liddle
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  ABSTRACT: We have developed a novel, sub-pixel alignment algorithm based on calculating a 3 × 3 array of residual values of the fit of an auto-correlation of an alignment mark template with the cross-correlation of the template with an imaged mark. The residual array is then fit by a second order polynomial, and the location having the minimum residual – the optimum alignment location – is determined analytically from the polynomial. This method naturally interpolates between the discrete pixels of the alignment mark and template images. The method is robust and can be used effectively with signal-to-noise ratios as low as −4 dB. Its performance is enhanced by appropriate choice of mark material, with Au marks with a signal-to-noise ratio of 0.48 dB yielding a factor of two. Alignment repeatabilities of ±2 nm were obtained using 5 nm Cr/50 nm Au marks with a 5 nm pixel. Using a 10 nm pixel, accuracies of 4.3 nm, 3σ were achieved with Au/Cr marks while 360 nm of Si topography yielded repeatabilities of 14.8 nm, 3σ or 19.7 nm, 3σ with a 100 nm resist coating. The technique was employed in the fabrication of a zone plate using two aligned exposures. Overlay values better than 5 nm were observed.
  Microelectronic Engineering.
• Article: X-ray magnetic microscopy for correlations between magnetic domains and crystal structure

  G. Denbeaux, E Anderson, B. Bates, W Chao, J A Liddle, B Harteneck, A. Pearson, F. Salmassi, G. Schneider, P Fischer, T. Eimüller, S. Taylor, H. Chang, G.J. Kusinski
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  ABSTRACT: Accurately determining the resolution of x-ray microscopes has been a challenge because good test patterns for x-ray microscopy have been hard to make. We report on a sputter-deposited multilayer imaged in cross section as a test pattern with small features and high aspect ratios. One application of high-resolution imaging is magnetic materials. Off-axis bend magnet radiation is known to have a component of circular polarization which can be used for x-ray magnetic circular dichroism. We calculate the integrated circular polarization collected by the illumination optics in the XM-1 full-field x-ray microscope.
  http://dx.doi.org/10.1051/jp4:20030126.