Analysis of Defects in Block Copolymer Thin Films

• Author / Creator

  Murphy, Jeffrey Nathaniel

• 2015 marks the 50th anniversary of Moore's law, which has described the exponential progress in semiconductor patterning technologies, enabling creation of smaller circuitry features at greater densities. These continued hardware developments, economically mass manufactured, have made possible computer technologies which have revolutionized daily life. The continued shrinking of features has largely been enabled via conventional photolithography, however inherent limitations due to the wavelength of light used mean that alternative technologies are required to continue the trend. Block copolymers are a self-assembling material which can be used as a stencil (or mask) to pattern arrays of periodic nanoscale surface features, in a manner which would complement photolithography and conventional CMOS manufacturing, while preserving economic mass production. Defects in block copolymer structures could limit adoption of this technology, as industry targets strive for less than 1 defect per 100 mm wafer. Consequently numerous efforts have sought to address the issue with various annealing techniques and guiding structures employed to enable quick, uniform, defect-free patterning of large areas. This thesis describes the computer-automated analysis of defects in striped patterns formed using block copolymers: focusing on topological defects (disclinations and dislocations), pattern orientation, and irregularity of features through line-edge and line-width roughness. The tool, ADAblock, has been developed for use with ImageJ and is open source and free for anyone to use and to modify. The tool has been made freely available online, with the intent that as an open-source tool, it can lead to greater accessibility of the analysis and uniformity of data between research groups. While defects in lamellar polystyrene-block-poly(methyl methacrylate) line patterns have been widely studied, the embedded nature of cylindrical domains has limited their analysis. Here, we focus primarily on defects in polystyrene-block-poly(2-vinylpyridine) cylinders arranged in monolayers on the native oxide surface of silicon wafers, with the P2VP domains metallized with platinum to enable SEM imaging. The analysis performed by ADAblock is applied to develop a better understanding of surface morphology and how film thickness affects defectivity within the monolayer regions and as a function of distance from the edge of islands.

• Subjects / Keywords

  • Image analysis
  • Nanomaterials
  • Defects
  • Nanotechnology
  • Lithography
  • Block copolymers
  • Self-assembly
  • Chemistry
  • Polystyrene-block-poly(2-vinylpyridine)
  • Polymers
  • Patterns
  • Thin films
  • Annealing
  • Microscopy

• Graduation date

  Fall 2015

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3C824R3R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.