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Proceedings Paper

Defect reduction of high-density full-field patterns in jet and flash imprint lithography
Author(s): Lovejeet Singh; Kang Luo; Zhengmao Ye; Frank Xu; Gaddi Haase; David Curran; Dwayne LaBrake; Douglas Resnick; S. V. Sreenivasan
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Paper Abstract

Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash Imprint Lithography (J-FIL) involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned resist on the substrate. Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the defect specifications of high end memory devices. Typical defectivity targets are on the order of 0.10/cm2. This work summarizes the results of defect inspections focusing on two key defect types; random non-fill defects occurring during the resist filling process and repeater defects caused by interactions with particles on the substrate. Non-fill defectivity must always be considered within the context of process throughput. The key limiting throughput step in an imprint process is resist filling time. As a result, it is critical to characterize the filling process by measuring non-fill defectivity as a function of fill time. Repeater defects typically have two main sources; mask defects and particle related defects. Previous studies have indicated that soft particles tend to cause non-repeating defects. Hard particles, on the other hand, can cause either resist plugging or mask damage. In this work, an Imprio 500 twenty wafer per hour (wph) development tool was used to study both defect types. By carefully controlling the volume of inkjetted resist, optimizing the drop pattern and controlling the resist fluid front during spreading, fill times of 1.5 seconds were achieved with non-fill defect levels of approximately 1.2/cm2. Longevity runs were used to study repeater defects and a nickel contamination was identified as the key source of particle induced repeater defects.

Paper Details

Date Published: 2 April 2011
PDF: 8 pages
Proc. SPIE 7970, Alternative Lithographic Technologies III, 797007 (2 April 2011); doi: 10.1117/12.879933
Show Author Affiliations
Lovejeet Singh, Molecular Imprints, Inc. (United States)
Kang Luo, Molecular Imprints, Inc. (United States)
Zhengmao Ye, Molecular Imprints, Inc. (United States)
Frank Xu, Molecular Imprints, Inc. (United States)
Gaddi Haase, Molecular Imprints, Inc. (United States)
David Curran, Molecular Imprints, Inc. (United States)
Dwayne LaBrake, Molecular Imprints, Inc. (United States)
Douglas Resnick, Molecular Imprints, Inc. (United States)
S. V. Sreenivasan, Molecular Imprints, Inc. (United States)

Published in SPIE Proceedings Vol. 7970:
Alternative Lithographic Technologies III
Daniel J. C. Herr, Editor(s)

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