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Title: Three Dimensional Assembly in Directed Self-assembly of Block Copolymers

Abstract

The three-dimensional assembly of poly (styrene-b-methyl methacrylate) (PS-b-PMMA) in chemoepitaxy and graphoepitaxy directed self-assembly (DSA) was investigated using scanning transmission electron microscopy (STEM) tomography. The tomographic characterization revealed hidden morphologies and defects at the BCP- chemical pattern interface in lamellar DSA, and probed the formation of cylinders at the bottom of cylindrical DSA for contact hole shrink. Lastly, future work will include control over 3D assembly in sub-10 nm processes.

Authors:
 [1];  [2];  [2];  [3];  [4];  [4];  [1]
  1. Univ. of Chicago, IL (United States). Inst. for Molecular Engineering; Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
  2. Univ. of Chicago, IL (United States). Inst. for Molecular Engineering
  3. Tokyo Ohka Kogyo Co., Ltd., Kanagawa (Japan)
  4. Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1352873
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Photopolymer Science and Technology
Additional Journal Information:
Journal Volume: 29; Journal Issue: 5; Journal ID: ISSN 0914-9244
Publisher:
The Society of Photopolymer Science and Technology (SPST)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Directed self-assembly; block copolymer, lithography; contact hole; transmission electron microscopy; metrology

Citation Formats

Segal-Peretz, Tamar, Zhou, Chun, Ren, Jiaxing, Dazai, Takahiro, Ocola, Leonidas E., Divan, Ralu N. S., and Nealey, Paul F. Three Dimensional Assembly in Directed Self-assembly of Block Copolymers. United States: N. p., 2016. Web. doi:10.2494/photopolymer.29.653.
Segal-Peretz, Tamar, Zhou, Chun, Ren, Jiaxing, Dazai, Takahiro, Ocola, Leonidas E., Divan, Ralu N. S., & Nealey, Paul F. Three Dimensional Assembly in Directed Self-assembly of Block Copolymers. United States. doi:10.2494/photopolymer.29.653.
Segal-Peretz, Tamar, Zhou, Chun, Ren, Jiaxing, Dazai, Takahiro, Ocola, Leonidas E., Divan, Ralu N. S., and Nealey, Paul F. 2016. "Three Dimensional Assembly in Directed Self-assembly of Block Copolymers". United States. doi:10.2494/photopolymer.29.653. https://www.osti.gov/servlets/purl/1352873.
@article{osti_1352873,
title = {Three Dimensional Assembly in Directed Self-assembly of Block Copolymers},
author = {Segal-Peretz, Tamar and Zhou, Chun and Ren, Jiaxing and Dazai, Takahiro and Ocola, Leonidas E. and Divan, Ralu N. S. and Nealey, Paul F.},
abstractNote = {The three-dimensional assembly of poly (styrene-b-methyl methacrylate) (PS-b-PMMA) in chemoepitaxy and graphoepitaxy directed self-assembly (DSA) was investigated using scanning transmission electron microscopy (STEM) tomography. The tomographic characterization revealed hidden morphologies and defects at the BCP- chemical pattern interface in lamellar DSA, and probed the formation of cylinders at the bottom of cylindrical DSA for contact hole shrink. Lastly, future work will include control over 3D assembly in sub-10 nm processes.},
doi = {10.2494/photopolymer.29.653},
journal = {Journal of Photopolymer Science and Technology},
number = 5,
volume = 29,
place = {United States},
year = 2016,
month = 9
}

Journal Article:
Free Publicly Available Full Text
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  • Characterization of the three-dimensional (3D) structure in directed self-assembly (DSA) of block copolymers is crucial for understanding the complex relationships between the guiding template and the resulting polymer structure so DSA could be successfully implemented for advanced lithography applications. Here, we combined scanning transmission electron microscopy (STEM) tomography and coarse-grain simulations to probe the 3D structure of P2VP- b-PS- b-P2VP assembled on prepatterned templates using solvent vapor annealing. The templates consisted of nonpreferential background and raised guiding stripes that had PS-preferential top surfaces and P2VP-preferential sidewalls. The full 3D characterization allowed us to quantify the shape of the polymer domainsmore » and the interface between domains as a function of depth in the film and template geometry and offered important insights that were not accessible with 2D metrology. Sidewall guiding was advantageous in promoting the alignment and lowering the roughness of the P2VP domains over the sidewalls, but incommensurate confinement from the increased topography could cause roughness and intermittent dislocations in domains over the background region at the bottom of the film. The 3D characterization of bridge structures between domains over the background and breaks within domains on guiding lines sheds light on possible origins of common DSA defects. The positional fluctuations of the PS/P2VP interface between domains showed a depth-dependent behavior, with high levels of fluctuations near both the free surface of the film and the substrate and lower fluctuation levels in the middle of the film. As a result, this research demonstrates how 3D characterization offers a better understanding of DSA processes, leading to better design and fabrication of directing templates.« less
  • Directed assembly of block copolymer thin films is recognized as a high-throughput, low-cost complement to optical lithography with the ability to overcome the 32 nm natural resolution limit of conventional lithographic techniques. For bulk block copolymer systems, desired feature sizes ranging from 5 to 100 nm can be obtained by controlling the molecular weight and composition of a block copolymer, as long as the bulk order-disorder temperature (ODT) is such that the copolymer is well-segregated at the processing conditions. However, our studies on graphoepitaxially aligned cylindrical morphology block copolymer monolayer and bilayer films demonstrate that, as domain sizes are reduced,more » the block copolymer becomes increasingly susceptible to an unacceptably high density of thermally generated defects, resulting in a significant reduction of the ODT. Thus, in thin films, the minimum feature spacing accessible is limited by thermal defect generation and not by the bulk ODT. Our experimental studies on monolayer films of cylindrical morphology polystyrene-b-poly(2-vinyl pyridine) with microdomain spacings approaching 20 nm reveal that defect densities and the ODT are surprisingly sensitive to variations as small as 2 nm in the microdomain spacing. Additionally, the monolayer and bilayer ODT differ by nearly 100 C when the monolayer domain spacing is 20 nm, while the difference is only 20 C when the monolayer domain spacing is 22 nm. We explain this behavior using a quantitative estimation of the energetic cost of defect production in terms of the domain spacing, {chi}N, and block copolymer composition. These studies reveal unexpected consequences on the equilibrium defect densities of thin film block copolymers which must be accounted for when designing a block-copolymer-based directed-assembly process.« less