skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Pattern Fidelity in Nanoimprinted Films using CD-SAXS

Abstract

The primary measure of process quality in nanoimprint lithography (NIL) is the fidelity of pattern transfer, comparing the dimensions of the imprinted pattern to those of the mold. As a potential next generation lithography, NIL is capable of true nanofabrication, producing patterns of sub-10 nm dimensions. Routine production of nanoscale patterns will require new metrologies capable of non-destructive dimensional measurements of both the mold and the pattern with sub-nm precision. In this article, a rapid, non-destructive technique termed Critical Dimension Small Angle X-ray Scattering (CD-SAXS) is used to measure the cross sectional shape of both a pattern master, or mold, and the resulting imprinted films. CD-SAXS data are used to extract periodicity as well as pattern height, width, and sidewall angles. Films of varying materials are molded by thermal embossed NIL at temperatures both near and far from the bulk glass transition (TG). The polymer systems include a photoresist, representing a mixture of a polymer and small molecular components, and two pure homopolymers. Molding at low temperatures (T-TG < 40 C) produces small aspect ratio patterns that maintain periodicity to within a single nanometer, but feature large sidewall angles. While the pattern height does not reach that of the moldmore » until very large imprinting temperatures (T-TG {approx} 70 C), the pattern width of the mold is accurately transferred for T-TG > 30 C. In addition to obtaining basic dimensions, CD-SAXS data are used to assess the origin of loss in pattern fidelity.« less

Authors:
; ; ; ; ; ; ; ; ;  [1];  [2];  [2]
  1. (Michigan)
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1008959
Resource Type:
Conference
Resource Relation:
Conference: SPIE International Symposium Microlithography 2005;Feb. 27 - March 4, 2005;San Jose, California USA
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; FILMS; PATTERN RECOGNITION; NANOSTRUCTURES; SMALL ANGLE SCATTERING; X-RAY DIFFRACTION; NONDESTRUCTIVE ANALYSIS; POLYMERS; FABRICATION; ACCURACY

Citation Formats

Jones, R.L., Soles, C.L., Lin, E.K., Wu, W-L., Hu, W., Reano, R.M., Pang, S.W., Weigand, S.J., Keane, D.T., Quintana, J.P., NIST), and NWU). Pattern Fidelity in Nanoimprinted Films using CD-SAXS. United States: N. p., 2006. Web.
Jones, R.L., Soles, C.L., Lin, E.K., Wu, W-L., Hu, W., Reano, R.M., Pang, S.W., Weigand, S.J., Keane, D.T., Quintana, J.P., NIST), & NWU). Pattern Fidelity in Nanoimprinted Films using CD-SAXS. United States.
Jones, R.L., Soles, C.L., Lin, E.K., Wu, W-L., Hu, W., Reano, R.M., Pang, S.W., Weigand, S.J., Keane, D.T., Quintana, J.P., NIST), and NWU). Mon . "Pattern Fidelity in Nanoimprinted Films using CD-SAXS". United States. doi:.
@article{osti_1008959,
title = {Pattern Fidelity in Nanoimprinted Films using CD-SAXS},
author = {Jones, R.L. and Soles, C.L. and Lin, E.K. and Wu, W-L. and Hu, W. and Reano, R.M. and Pang, S.W. and Weigand, S.J. and Keane, D.T. and Quintana, J.P. and NIST) and NWU)},
abstractNote = {The primary measure of process quality in nanoimprint lithography (NIL) is the fidelity of pattern transfer, comparing the dimensions of the imprinted pattern to those of the mold. As a potential next generation lithography, NIL is capable of true nanofabrication, producing patterns of sub-10 nm dimensions. Routine production of nanoscale patterns will require new metrologies capable of non-destructive dimensional measurements of both the mold and the pattern with sub-nm precision. In this article, a rapid, non-destructive technique termed Critical Dimension Small Angle X-ray Scattering (CD-SAXS) is used to measure the cross sectional shape of both a pattern master, or mold, and the resulting imprinted films. CD-SAXS data are used to extract periodicity as well as pattern height, width, and sidewall angles. Films of varying materials are molded by thermal embossed NIL at temperatures both near and far from the bulk glass transition (TG). The polymer systems include a photoresist, representing a mixture of a polymer and small molecular components, and two pure homopolymers. Molding at low temperatures (T-TG < 40 C) produces small aspect ratio patterns that maintain periodicity to within a single nanometer, but feature large sidewall angles. While the pattern height does not reach that of the mold until very large imprinting temperatures (T-TG {approx} 70 C), the pattern width of the mold is accurately transferred for T-TG > 30 C. In addition to obtaining basic dimensions, CD-SAXS data are used to assess the origin of loss in pattern fidelity.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Apr 10 00:00:00 EDT 2006},
month = {Mon Apr 10 00:00:00 EDT 2006}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • Microsensors often do not have the selectivity to chemical species available in large laboratory instruments. A new type of pattern recognition algorithm is used to classify mixtures of H{sub 2} with NO{sub 2} and O{sub 2}. The microsensors used are thin film catalytic metal field effect transistors and chemiresistors on the Sandia Robust Sensor platform. For this study pure Pd thin films and Pd/Ni alloys are shown to provide good classification of mixtures containing NO{sub 2} from those containing O{sub 2} or no oxidant.
  • Recently picosecond techniques have been used to generate surface acoustic waves (SAW) with wavelengths of a few microns. Previously generation of short SAW wavelengths required a laser pulse duration shorter than the transit time of the acoustic wave as it traverses the spatial pattern produced by the laser and a thermal relaxation time much faster than the acoustic time constant. In this paper we wish to report an investigation using spatially and temporally modulated light beams using long lasers pulses as a means to generate short acoustic wavelengths. Such a method may be useful in measuring the elastic modulus ofmore » thin films. The experiment that is being conducted utilizes two laser beams, one at frequency, vo, and the other at a shifted frequency, vo-v{prime}, to form a traveling interference pattern. The method of generating these frequencies will be described. By adjusting the angle between the two laser beams, the surface wave speed of an arbitrary material used for a thin film can be selectively matched. Using a YAG laser at 1064 rim to create the moving gratings, surface acoustic wavelengths of 1-3 microns may be generated in a variety of materials. The penetration depth of the acoustic wave is approximately the wavelength itself, thus, this method is well suited for characterizing thin films. For multiple thin film layers of different materials, SAW can be selectively produced in any layer of interest provided the top layers are transparent enough to allow the laser energy to be deposited on the intended layer. The presence of these modulated surface waves is detected by a He-Ne laser using light scattering. From the measured surface acoustic wave velocity, Poisson`s ratio, and the specimen density, the elastic modulus may be calculated. Measurements in progress will be reported for a variety of materials.« less
  • We report results from ultra-small-angle x-ray scattering (USAXS) and transmission electron microscopy (TEM) of dilute silicate colloids that occur naturally in ground water from the U.S. Geological Society J-13 well, located near the Yucca Mountain Site in Nevada. Also included are results from our examination of a separate sample of this groundwater that had been treated by heating to 90 {sup o}C in contact with crushed Topopah Spring Tuff from the Yucca Mountain site. The USAXS measurements were done at the UNICAT undulator beamline at the Advanced Photon Source (APS) at Argonne National Laboratory. Power-law plots (scattering intensity versus momentummore » transfer) were fitted to the USAXS data. Colloids in the untreated J-13 groundwater were shown to have a fractal dimension of nearly 3, whereas colloids in the treated groundwater (EJ-13) have a dimensionality of approximately 2.4 over a length scale of approximately 3 to 300 nm. Similar power-law plots with dimension 3 characterized concurrent SAXS measurements from aqueous suspensions of Na-montmorillonite and NIST Brick Clay (NBS-67). We attribute these results to the sheet-silicate-layered structure of the clay colloids present in J-13 well water, montmorillonite, and 'brick clay' systems. The differences between EJ-13 and as-received J-13 are perhaps owing to exchange of calcium for sodium with the tuff. Radionuclide incorporation into, adsorption onto, or ion exchange with existing groundwater colloids may promote colloidal transport of radionuclides in groundwater. Such radionuclide-bearing colloids could thereby increase the concentrations of actinides in groundwater and enhance migration into human-accessible aquifers. Our results demonstrate the first application of USAXS to study the physical nature of such groundwater colloids, and represent perhaps one of the most dilute systems ever studied by small-angle scattering.« less
  • We report results from ultra-small-angle x-ray scattering (USAXS) and transmission electron microscopy (TEM) of dilute silicate colloids that occur naturally in ground water from the U.S. Geological Society J-13 well, located near the Yucca Mountain Site in Nevada. Also included are results from our examination of a separate sample of this groundwater that had been treated by heating to 90 {sup o}C in contact with crushed Topopah Spring Tuff from the Yucca Mountain site. The USAXS measurements were done at the UNICAT undulator beamline at the Advanced Photon Source (APS) at Argonne National Laboratory. Power-law plots (scattering intensity versus momentummore » transfer) were fitted to the USAXS data. Colloids in the untreated J-13 groundwater were shown to have a fractal dimension of nearly 3, whereas colloids in the treated groundwater (EJ-13) have a dimensionality of approximately 2.4 over a length scale of approximately 3 to 300 nm. Similar power-law plots with dimension 3 characterized concurrent SAXS measurements from aqueous suspensions of Na-montmorillonite and NIST Brick Clay (NBS-67). We attribute these results to the sheet-silicate-layered structure of the clay colloids present in J-13 well water, montmorillonite, and 'brick clay' systems. The differences between EJ-13 and as-received J-13 are perhaps owing to exchange of calcium for sodium with the tuff. Radionuclide incorporation into, adsorption onto, or ion exchange with existing groundwater colloids may promote colloidal transport of radionuclides in groundwater. Such radionuclide-bearing colloids could thereby increase the concentrations of actinides in groundwater and enhance migration into human-accessible aquifers. Our results demonstrate the first application of USAXS to study the physical nature of such groundwater colloids, and represent perhaps one of the most dilute systems ever studied by small-angle scattering.« less