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2011 - |
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Jan. 13 |
No TeleSeminar--Holiday
Schedule |
|
Jan. 27 |
Host: Srini
Raghavan, Materials Science and Engineering, University of Arizona
Presentation by:
Dinesh Thanu, Materials Science and Engineering, University of Arizona
Topic title: Liquid Mixtures of Urea and Choline Chloride
for Use in Back End of Line (BEOL) Cleaning
Abstract: Removal of post etch residues using a novel liquid
formulation containing a liquid (molten) mixture of two benign chemicals,
choline chloride and urea has been investigated. Residues created during
plasma etching of g- line and Deep UV (DUV) photoresist films on copper were
used for this study. Both types of residues were effectively removed using
eutectic mixtures of urea and choline chloride, at a molar ratio of 2:1, in
the temperature range of 40 to 70oC. Extent of removal has been
characterized using SEM, XPS and electrochemical techniques. Additionally,
it has been found that the residue removal can be obtained with a high
degree of selectivity with respect to low-k dielectric materials.
(PDF) |
|
Feb.
10 |
Host:
Ara Philipossian, Chemical and Environmental Engineering, University of
Arizona
Presented by: Dr. Rakesh K. Singh, Manager, WW CMP
Applications and New Business Development, Contamination Control Solutions, Entegris
Inc.
Topic title: "New Developments in Post-CMP Cleaning
Technology"
Abstract:
Recent advancements in the post-CMP (PCMP) cleaning technology for
next-generation applications will be discussed, with a special emphasis on
the design and characterization of PCMP cleaning polyvinyl alcohol (PVA)
brushes. Results of a number of case studies are presented with
representative data. In the first study, modified charge Planarcore® PVA
brushes were developed and characterized for zeta potential distribution at
different pH values. These enhanced negative zeta potential brushes provide
much improved PCMP cleaning performance in smaller-node, high-sensitivity
copper/low-k processes.
In the second study, a new generation of modified nodule shape
molded-through-the-core (MTTC) Planarcore brushes were developed for
specific wafer cleaning challenge. One such example was the near wafer edge
cleaning issue seen in an advanced application. Modified nodule brushes
provided differentiated cleaning action in various parts of the wafer and
required enhanced cleaning in the edge region. In the third test, several
commercially available slip-on-the-core (SOTC) and Planarcore MTTC brushes
were analyzed for tribological data using a benchtop tribometer. The effects
of four acidic and one alkaline PCMP cleaning chemistries were studies on
the brush PVA skin-friction and other tribological parameters, over a wide
range of brush rotational speeds.
In the fourth study, extended period chemical soak tests of brushes were
performed in five copper/low-k PCMP cleaning chemistries dilute
solutions, to quantify the effects of long term chemical exposure on the
brush PVA physical properties. It is important to understand such behavior
to achieve consistent cleaning performance over the entire lifetime of
brushes. In this study, most acidic PCMP cleans showed significant color
change of PVA as well as the soaking solutions, whereas all brushes had only
a limited change in the physical properties of PVA. Present
study demonstrates the usefulness of new brush
designs and characterization methods for advanced PCMP cleaning
applications. (PDF) |
|
Feb.
24 |
Host: Farhang Shadman,
Chemical and Environmental Engineering, University of Arizona
Presented by: Roy Dittler, Chemical and Environmental
Engineering, University of Arizona
Topic title:
Novel methods for reducing the usage of high-purity gases in SC Fabs
Abstract:
The
removal of moisture contamination in ultra high purity (UHP) gas
distribution systems was approached by using a novel technique dubbed,
pressure cyclic purge (PCP). Electro-polished stainless steel (EPSS) piping
was contaminated with moisture, from a controlled source, and then purged
using a conventional purge technique or a PCP technique. Moisture removal
rates and overall moisture removal was determined by measuring gas phase
moisture concentration in real time via a moisture analyzer that utilizes
cavity ring-down spectroscopy. When compared to conventional purge, PCP
reduced the time required and the purge gas needed to clean the UHP gas
distribution systems. Most recently, testing and modeling was performed to
test the effectiveness of PCP in systems with laterals; more specifically,
laterals with a “dead volume”. Lab test and model results showed that PCP,
though effective in removing moisture in piping with no laterals, is even
more efficient in removing moisture contamination from the laterals with a
“dead volume”. (PDF) |
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March 10 |
No
TeleSeminar -- Annual Review Meeting |
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March 24 |
No
TeleSeminar |
|
April 7 |
Host: Steve Nielsen/Inga Musselman, Department of
Chemistry, University of Texas-Dallas
Presented by:
1)
R. J. K. Udayana Ranatunga (graduate student); 2)
Ruhung Wang (research associate), University of Texas-Dallas
Topic title:
"Nanoparticle
aggregation and toxicity"
Abstract:
Part 1 – Presented by Udayana Ranatunga:
Functionalized single-walled carbon nanotubes (SWNTs) are widely applied in
biomedical science. To understand the interaction between SWNTs and
biological systems, various studies have attempted to use coarse grained
molecular dynamics (CGMD). However, there is limited validation of the
existing CG models of SWNTs. Here, we present CG models for both pristine
and carboxylated SWNTs which are validated against experimental dispersion
data. In addition, we present the first ever DLVO analysis of the colloidal
stability of parallel SWNTs and establish that the solvent-induced repulsion
between fullerenes, which is not considered in DLVO theory, is crucial to
obtain a correct physical picture of SWNT dispersibility. The results
presented here provide physical insight into the colloidal stability of
SWNTs, and can be applied to large-scale MD studies of biological systems.
Part 2 – Presented by Ruhung Wang: MWNTs are on an emerging
material on the roadmap and potentially have EHS implications. To
assess potential adverse ESH impacts of MWNTs, we studied two commercial
MWNT products, one pristine and one carboxylated. To facilitate biological
testing, the MWNTs were dispersed in aqueous solutions using two
bio-compatible surfactants: bovine serum albumin (BSA, a common blood
protein used often to disperse carbon nanotubes) and a tri-block copolymer
Pluronic F127. The effectiveness in dispersing MWNTs using BSA and Pluronic
F127 was compared. Our preliminary results indicated that Pluronic F127 is
a more effective dispersant than BSA. Dynamic light scattering measurements
of particle size distribution revealed less aggregated material in Pluronic
dispersions. In vitro cytotoxicity of MWNTs dispersed either in BSA
or in Pluronic solutions were assessed using an established mammalian cell
line. Pristine and carboxylated MWNTs dispersions prepared in BSA were
cytotoxic and significantly inhibited cell proliferation. A brief
centrifugation step of the dispersions removes large aggregates and reduces
cytotoxicity by ~ 10 fold. In contrast, both pristine and carboxylated
MWNTs dispersed in Pluronic F127 were much less cytotoxicity even without
centrifugation. Further investigation on the interaction between MWNT
particles and different dispersants will clarify the correlation between
particle aggregation and toxicity observed in this in vitro cell line
model system. (PDF) |
|
April 21 |
Presentation by:
Scott Boitano and Mia McCorkel, University of Arizona
Topic title: "Measuring Nano-Cytotoxicity Over Time: High
Throughput Detection of Cell Death and Cellular Signaling Pathways"
Abstract:
We have been studying nanoparticle toxicity on two
immortalized human derived cell lines that model high risk areas of
exposure: a HaCat skin epithelial cell line and a 16HBE14o- airway
epithelial cell line. Using cell death as an endpoint, and integrating use
of both standard high throughput techniques we have found that these
epithelial cell lines are quite resistant to most nanoparticles exposures up
to > 1000 ppm. To more closely understand the potential damage to the cell
following nanoparticle exposure, we have shifted to evaluating the effects
of nanoparticle exposure on specific cellular signaling pathways. We will
show data that details the detrimental effects of 24 hr nanoparticle
exposure on ATP-induced cellular signaling at levels of 10 – 25 ppm. We will
discuss further use of high throughput and standard techniques to best
evaluate potential cellular signaling pathways modifications as a
determinant of nanotoxicity. (PDF) |
|
May 5 |
No
TeleSeminar -- Spring Break |
|
May 19 |
Host:: Jim Farrell and Jim Baygents, Chemical and
Environmental Engineering, University of Arizona
Presented by: Jake Davis, Chemical and Environmental
Engineering, University of Arizona
Topic title: "Key Issues Affecting Water Use and Recycle
in High Volume Semiconductor Manufacturing"
Abstract:
There is growing
concern about the future availability and quality of public water supplies.
This concern
is driving
regulatory action that will
ultimately present significant
challenges to the
semiconductor manufacturing
industry. Future regulation will force
the semiconductor
manufacturing industry to both utilize
impaired water resources
and meet
stricter wastewater
discharge requirements.
These industry challenges and public concerns are described in this
presentation along with several pertinent water treatment technologies.
(PDF) |
|
June 2 |
Host: Alex Tropsha, University of North Carolina-Chapel Hill
Presented by: Denis Fourches and Alex Tropsha, UNC
Topic title: Computer-Aided Design of Nanomaterials with the
Desired Bioactivity and Safety Profiles
Abstract:
Evaluation of biological effects of nanomaterials (NMs) is of critical
importance for the future of nanotechnology in biomedical and industrial
applications. Experimental studies (especially, toxicological) are
time-consuming, costly, and often impractical calling for the development of
in silico approaches. We will discuss (i) the need of
electronic, inter-laboratory databases regrouping all published information
concerning NMs, especially their measured physical/chemical properties and
associated biological profiles; (ii) the challenging development of
new NM descriptors computationally derived from molecular dynamics
simulations and quantum chemistry calculations; and (iii) the
potential of cheminformatics methods to
develop statistically significant and externally predictive Quantitative
Nanostructure–Activity Relationship (QNAR) models (Fourches et al., ACS Nano,
2010, 4:5703-12; Fourches et al., Comb Chem High Throughput Screen. 2011,
14:217-25). We will also present the first study reporting the
computer-aided design of new carbon nanotubes with the desired bioactivity
and safety profiles: (1) we successfully developed robust QNAR models for 84
carbon nanotubes decorated with organic surface modifiers; (2) these models
were applied for virtual screening of a library of 240,000 ligands
potentially attachable to carbon nanotubes to identify hits with the
desired predicted bioactivity and toxicity properties; (3) selected
nanotubes decorated by the ligands indentified with the help of QNAR models
were experimentally synthesized and successfully validated by our
collaborator, Dr. Bing Yan at St. Jude Children Research Hospital. Our study
demonstrates how QNAR models can be used to predict activity profiles of NMs
and bias the design of new NMs towards products with the desired bioactivity
and safety profiles. (D. Fourches, D. Pu,
and A. Tropsha. Laboratory for
Molecular Modeling, UNC Eshelman School of Pharmacy, Chapel Hill, USA)
(PDF) |
|
June 16 |
Host:
Manish Keswani, Material Sciences and Engineering, University of Arizona
Presented by: Dr. Steven Verhaverbeke, Applied Materials
Inc.
Topic title: "Aspects of Single Wafer Processing Tools"
Abstract: In this talk, various aspects of single
wafer processing will be covered with an emphasis on cleaning tools. At
first some generalities of particles and particle distributions will be
given. Then, we will look at the behavior of particles in the gas phase and
the practical applications of these behavioral theories. Particularly, the
effect of charging will be covered and the design implications. Finally, all
of the common mechanically assisted cleaning technologies will be listed and
their applications in semiconductor manufacturing. (PDF) |
|
June 30 |
No TeleSeminar
-- July 4th Holiday |
|
|
PLEASE NOTE SUMMER SCHEDULE:
JULY, AUGUST, SEPTEMBER |
|
July 14 |
Host:
Farhang Shadman, Chemical & Environmental Engineering, University of Arizona
Presented by: Hao Wang, Chemical & Environmental Engineering,
University of Arizona
Topic title:
“Characterization
of the Surface Properties of Nanoparticles Using Moisture Adsorption Dynamic
Profiling”
Abstract:
Adsorption and
retention of molecular contaminants on nanoparticles (NPs) is a major factor
in determining the environmental and health effects of the particles. A
method has been developed for characterizing the surface properties that
contribute to the adsorption and desorption interactions. This method uses a
sample cell and an in-situ FTIR to obtain the time profiles of dynamic
interactions of adsorbing species on NP samples under different
temperatures. The results are then analyzed using a process simulator to
determine the fundamental properties such as capacity, affinity, rate
expressions, and activation energies of NP interactions with contaminants.
The method is illustrated using moisture as a representative model compound
and particles of SiO2, HfO2, and CeO2,
which are three oxides used in semiconductor manufacturing. The results
indicate that the surface interaction parameters are species, particle size
and temperature dependent. The size effect is expected to be a major
contributor to the synergistic and enhanced environmental and health impact
of NPs compared to larger particles. Factors contributing to the
environmental and health impact of NPs (extent of surface coverage,
capacity, and activation energy of retention) are higher for smaller
particles of the same oxide. Based on the observed activation energies, the
strong interaction with adsorbing contaminants is a key characteristic that
makes NPs different from larger particles and contributes to their potential
environmental and health impact. (PDF) |
|
July 28 |
No TeleSeminar |
|
Aug. 11 |
Host:
Christopher Ober, Materials Science & Engineering, Cornell University
Presented by:
Christine Ouyang, Materials Science and Engineering, Cornell University
Topic title:
“Environmentally Friendly Non-Aqueous Development”
Abstract:
Studies of environmentally friendly solvent-based developers:
The production of micro-electronic devices is a highly solvent-intensive
process. It consumes a large volume of organic solvents, inorganic
acids/bases and purified water, accordingly generates the same amount of
waste. Besides the environmental issue, inherent physical properties of
conventional solvents, such as high surface tension, are considered
undesirable for high aspect-ratio patterns. To overcome these problems,
supercritical carbon dioxide (scCO2) and silicone fluids have
been identified as promising alternatives.
ScCO2 is a single-phase fluid that exists above
the critical point of carbon dioxide (Tc=31 oC, Pc=7.4
MPa). It is nontoxic, nonflammable, inert under most chemical conditions,
and can be easily recycled. In general, scCO2 is a good solvent
for small molecules but not for polymeric materials, particularly those
lacking fluorine or silicon moieties. Therefore, processing of conventional
polymer-based photoresists in scCO2 requires either co-solvents
or additives which can enhance the solvating power of scCO2.
Recently, we have shown that fluorinated quaternary ammonium salts can
increase the solubility of conventional polymeric photoresists in scCO2,
which enables high resolution patterning under electron-beam exposure
conditions. Another important approach is to employ molecular imaging
materials. Suitably functionalized molecular glass (MG) photoresists have
sufficient solubility in scCO2, along with the benefit
of high-resolution patterning and improved line
edge roughness (LER).
Silicone fluids, also known as linear methyl siloxanes, are a
class of environmentally friendly, non-polar solvents with zero
ozone-depletion and low global warming potentials. They have been used for
several industrial applications, such as water removal in microelectronics
processing, lubrication and cleaning, but no examples of application in
photoresist processing has been reported. The solvent strength of silicone
fluids is weaker than that of saturated hydrocarbons but significantly
stronger than that of the commercially available saturated
hydrofluorocarbons, and can be enhanced by mixing with co-solvents.
In this presentation, we show the development process in scCO2
and silicone fluids. Both conventional photoresists and molecular glass
resists were successfully patterned, with feature sizes as small as 30 nm.
(PDF) |
|
Aug. 25 |
No TeleSeminar |
|
Sep. 8 |
Host: Reyes
Sierra, Department of Chemical & Environmental Engineering, University of Arizona
Presented by:
Reyes Sierra, Chemical & Environmental Engineering, University of Arizona
Topic title: “Assessment of
nanotoxicity using cell-microelectronic sensing”
Abstract: The objective of
this study was to evaluate and validate impedance-based Real Time
Cell-Electronic Sensing (RT-CES) as a high throughput technique for dynamic
monitoring of nanoparticle cytotoxicity. A series of inorganic oxide
nanoparticles was tested which included, among others, ceria, silica, and
alumina, all of which are important components in chemo-mechanical
planarization (CMP) slurries, and other emerging nanomaterials utilized in
semiconductor manufacturing. Target cells used for the study were human
lung epithelial cells, 16HBE14o-. Cytotoxicity varied widely
depending on the nature of the inorganic oxide. The inhibitory
concentrations determined with the new RT-CES technique correlated well with
those generated by a commonly used cytotoxicity assay (i.e. MTT, indicator
of cell redox activity). The results obtained demonstrate the potential of
this high throughput technique for screening cytoxicity of nanomaterials.
Impacts of media on aggregation of nanoparticles are also discussed.
(PDF) |
|
Sep. 22 |
No TeleSeminar |
|
Oct. 6 |
Host: Anthony
Muscat, Chemical & Environmental Engineering, University of Arizona
Presented by: David F. Hilscher, IBM Semiconductor
Research and Development Center
Topic title: "A review of variability reduction
strategies: intrinsic advantages of e-sulfuric and single wafer
cleaning"
Abstract:
The leverage and importance of cleaning and surface preparation to device
manufacturing only continues to grow despite predictions to the contrary
more than a decade ago by many in the field. Yield improvement driven
through
reductions in variability has been a theme over the past several years, so
this
presentation will focus on the sources of variability in wets processing and
their countermeasures.
The presentation will use a green resist strip technology called
electrolyzed sulfuric acid (e-Sulfuric) and single wafer cleaning as
highlighted examples to discuss variability reduction. Both of those
cleaning technologies have variability reduction elements intrinsic to their
approach. (PDF) |
|
Oct. 20 |
Host: Alex
Tropsha,
Division of Medicinal Chemistry
and Natural Products,
UNC Eshelman School of Pharmacy,
University of North Carolina at Chapel Hill
Presented by:
Dr. Nathan
Baker,
Pacific Northwest National Laboratory
Topic title: "Informatics
and Standards for Nanomedicine Technology"
Abstract:
Nanomedicine deals with the development and
biomedical application of nanotechnology-based methods and products.
Nanotechnology provides the ability to manipulate and characterize matter at
the nanoscale. This ability has enabled the research and development of
nanoscale-sized objects such as nanoparticles and other nanomaterials for
biomedical applications that have the potential to improve the diagnosis and
treatment of diseases. In particular, nanotechnology has the potential to
make medicine more personalized. However, to realize the goal of
personalized medicine, multidisciplinary teams of collaborating scientists
must manage and analyze large amounts of data generated from basic,
pre-clinical and clinical studies, and clinical outcomes in an integrated
way. Before one can effectively use the large and diverse nanomedicine
datasets in translational research efforts to achieve the goal of
personalized medicine, there are several unresolved issues related to
information management in nanomedicine that have to be addressed. Three
areas of nanomedicine informatics are critical in addressing these issues:
information resources; taxonomies, controlled vocabularies and ontologies;
and, information standards. Progress towards resolving these issues is
essential to the rapidly growing field of nanomedicine informatics. (PDF) |
|
Nov. 3 |
Host: Yongsheng
Chen,
School of Civil and Environmental Engineering, Georgia Institute of
Technology
Presented by:
Wen Zhang (Ph.D., E.I.T., Postdoctoral fellow)
and Yongsheng Chen* (Ph.D., Associate Professor, PI)
Topic title: "Cytotoxic
effects of engineered nanoparticles at the bio-nano interface"
Abstract:
Our previous studies have indicated that at the bio-nano interface, sorption
behavior and cytotoxicity of engineered nanoparticles (ENPs), is affected by
particle size and size-dependent particle properites (e.g., hydrophobicity,
surface charge, aggregation state, ion release potential, crystallinity, and
shape). ENPs may induce cytotoxic effects through binding to cell surface
ligands, direct contact with cellular regions leading to changes in free
surface energy, conformational changes or oxidant injury caused by reactive
oxygen species (ROS). In this presentation, we will introduce the
experiments that we have conducted to address some of the above interfacial
damage to the cells from the physical and chemical perspectives. Physical
damages to the cell surfaces have been investigated via measuring cell
surface properties of hardness or softness, elasticity, adhesiveness, and
surface electric potential upon exposure to NPs. In the case of hematite
(α-Fe2O3) and E. coli cells, we found that
E. coli cells deformed severely after 45-min exposure to hematite NPs as
well as lost cellular integrity and surface appendages (e.g., pili and
flagella). The cell surface became coarser, stiffer, and more adhesive with
hematite NPs attached. Moreover, surface potential shifted to more
negatively charged with the attachment of hematite NPs. The restuls give
insight into the interfacial damages of NPs to the cell surfaces and present
a unique angle of understanding the disurption mechanisms on cell surface
integrity from a physical perspective.
Regarding the chemical damages to cell membrane, the generation of ROS is
the central cause for lipid peroxidation, enzyme or protein oxidation. Thus,
we conducted a systematical examination of the ROS formation on various
selected ENPs (i.e., TiO2, CeO2, CuO, QDs, Au, Ag, and
graphene oxide) in an effort of comparing their toxicity potentials based on
the produced ROS and futher understanding size effects. In the case of CdSe/ZnS
QDs, we detected the formation of superoxide radical (O2•−)
under UV irradiation (254 nm), whereas singlet oxygen (1O2),
and hydroxyl radical (•OH) were not found or lower than the detection
limits. The ROS eventualy led to photo-oxidative dissolution of QDs and
toxic heavy metals (Cd and Zn) were released, which may have toxicological
significance. [Wenjie
Sun, Antonia Luna-Velasco, Reyes Sierra-Alvarez, Jim A. Field]
(PDF) |
|
Nov. 17 |
Host: Juan J. de
Pablo, Director, Materials Research Science and Engineering Center,
Department of Chemical and Biological Engineering, University of
Wisconsin-Madison
Presented by: Gregory N. Toepperwein, Department of Chemical
and Biological Engineering, University of Wisconsin-Madison
Title: "Modeling of Environmentally Friendly Siloxane-Based
Lithography Solvents"
Abstract: Future lithographic development demands new
solvents capable of addressing pattern collapse while catering to an
ever-growing environmental concern. Siloxane-based solvents provide an
opportunity to address these challenges. Coupling hands on experimental
work with computer simulation enables the characterization of effective
chemical platforms as well as providing the first information on the
mechanisms of action for this new class of lithographic solvents. (PDF)
(PPT-
w/movie) |
|
Dec. 1 |
Host: Jim Field,
Chemical and Environmental Engineering, University of Arizona
Presented by: Wenjie "Alex" Sun, Chemical and Environmental
Engineering, University of Arizona
Topic title: "The
Role of Protein Oxidation in the Toxicity of Inorganic Nanoparticles"
Abstract:
Growth
in the nanotechnology application is leading to increased production of
nanoparticles (NPs). The semiconductor
manufacturing industry is already using NPs of SiO2, Al2O3
and CeO2 in the chemical mechanical planarization process.
Additionally, a wide variety of inorganic NPs are being considered for
emerging processes in the industry. This has given rise to concerns
about the potential adverse and toxic effects to the biological system and
environment. Oxidative stress to cells caused by NPs through the formation
of reactive oxygen species (ROS) or via direct oxidation of biomolecules is
considered to be an important mechanism of NPs toxicity. A rapid method has
been established to monitor the ROS production by NPs via the reaction with
L-dopa in the presence of oxygen at the University of Arizona. In this
study, a protein oxidation assay was developed to determine the role of
protein oxidation in NPs toxicity. The protein oxidation was evaluated by
use of the enzyme-linked immunosorbent assay (ELISA) to measure the protein
carbonyl derivatives as the product of protein oxidation. The testing
identified that Cu, CuO, Mn2O3 and Fe0 are
the reactive NPs causing protein oxidation; whereas, many of the other NPs
tested are not reactive or very slow reactive with proteins. Particle size
and presence of oxygen also played important roles in the protein oxidation.
(PDF) |
|
Dec. 15 |
Host: Duane
Boning,
Professor of
Electrical Engineering and Computer Science MIT
Presented by:
Prof. Ahmed Busnaina, William Lincoln Smith Chair Professor at Northeastern
University and Director of the NSF Nanoscale Science and Engineering Center
for High Rate Nanomanufacturing (CHN)
Topic title:
"Rethinking
Manufacturing: Directed Assembly Based Nanomanufacturing and the Role of CMP"
Abstract:
Present fabrication
facilities that manufactures nanoscale devices such as consumer electronics
costs $5-10 billion. This high cost of entry barrier completely shuts out
small and medium sized businesses. Dramatically lowering such barriers would
spur innovation and the creation of entirely new industries. A directed
assembly based nanomanufacturing factory could be built for as low as $25
million, a fraction of today’s cost, making nanotechnology accessible to
millions of new innovators and entrepreneurs and unleash a wave of
creativity in the same way as the advent of the PC did for computing.
The NSF Center
for High-rate Nanomanufacturing (CHN) is developing tools and processes
to conduct
fast massive directed assembly of nanoscale elements by controlling the
forces required to assemble, detach, and transfer nanoelements at high rates
and over large areas.
The center
has developed templates with nanofeatures to direct the
assembly of carbon nanotubes and nanoparticles (down to 10 nm) into
nanoscale structures in a short time (in seconds) and over a large area
(measured in inches). The nanotemplates
can also be used to assemble conducting polymers and demonstrated that the
patterned polymer can be transferred onto a second substrate.
We have developed a damascene template, fabricated by micro/nanofabrication
process and chemical mechanical polishing methods (CMP) to provide a
robust/reusable template capable of directed assembly of nanoscale
structures. In this template the metallic micro and nanowires are connected
to a conductive film (gold or tungsten) underneath the insulating substrate
and CMP is used to ensure that uniform charges for the nanowires for uniform
directed assembly over the wafer.
The center has many applications where the technology has been demonstrated.
For example, a room temeprture and pressure SWNT interconnect was developed.
A
nonvolatile memory switches using (SWNTs) or molecules assembled on a wafer
level. A new biosensor chip
(0.02 mm2) capable of detecting multiple biomarkers
simultaneously and the bio sensor can be
in vitro and
in vivo with a detection limit that’s 200 times lower than current
technology. A new autonomous chemical sensor with a low detection limit
that less than 1 mm3 that can collect
and transmits data. The center has developed the fundamental science and
engineering platform necessary to manufacture a wide array of applications
ranging from electronics, energy, and materials to biotechnology. (PDF) |
|
Dec. 29 |
No TeleSeminar--Holiday
Schedule |
|
