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| Jan. 11 |
Host: David Graves,
Department of Chemical Engineering, University of California-Berkeley
Presentation by: Mark
Goldman, Department of Chemical Engineering,
University of
California-Berkeley
Topic: "Beam Studies of
Ultra Low-K Film Damage"
Abstract: As the
semiconductor industry moves towards devices with ever-smaller critical
dimensions, RC delay is becoming an increasingly important technological
barrier to device performance. To overcome these problems, new materials
such as copper interconnects and low-k films have been developed, and new
processing methods, such as the damascene process, are being used. However,
with these new technologies, new hurdles must be overcome before they can be
used to their full potential. One of these hurdles is the incompatibility
of ultra low-k films with the photoresist strip process.
Our research is designed to elucidate fundamental mechanisms of
plasma-induced ULK damage occurring during plasma etch and strip, and to
suggest ways to minimize or eliminate it in an environmentally friendly way.
Our current focus is on the role of radical chemistry and ions on ultra
low-k film damage. It is widely known that oxygen plasma processing
significantly damages methyl-doped ultra low-k films, and we will show that
the removal of the methyl groups from the ultra low-k film is a diffusion
limited process that follows Deal-Grove-like behavior. In addition, we
will show the effect of other radical chemistries and rare-gas ion
bombardment on the low-k films. (PDF) |
| Jan. 25 |
Host: Ara
Philipossian, Department of Chemical and Environmental Engineering, University of Arizona
Presentation by: Daniel Rosales-Yeomans, Department of Chemical
and Environmental Engineering, University of Arizona
Topic:
"Evaluation and Modeling of the Effect of Novel Pad Grooves for Copper CMP"
Abstract: Differences in pad grooves can affect the chemical
processes in copper CMP by modulating the: (a) net flow under the wafer, (b)
process temperature, and (c) reactants and polish debris concentrations.
Furthermore, changes in the mechanical abrasion of the passive film may
occur due to differences in pad grooving which can in turn affect: (a)
slurry film thickness under the wafer, (b) shear force, (c) pad
compressibility and (d) pad-wafer contact area. The effective transport of
slurry in and out of the pad-wafer interface becomes critical particularly
for processes in which by-products are detrimental to polishing rates. In
this study, novel groove patterns (i.e. a combination of logarithmic and
spiral, as well as slanted concentric grooves) where evaluated. Some of
these designs were intended to effectively control the introduction of fresh
slurry into, and the discharge of spent slurry and debris, out of the
pad-wafer interface. Polishing was performed on polyurethane pads divided
into two different groups of groove designs. Group 1 included combinations
of logarithmic and spiral grooves in different directions (positive and
negative). Positive grooves were intended to retain the slurry while
negative grooves were meant to aid in slurry and by-product discharge. Group
2 consisted of pads with concentric grooves slanted at different degrees
(zero, 20 and 30 degrees) and directions (positive if leaning towards the
edge of the pad, and negative if leaning towards the center of the pad). The
pads where tested and statistically compared to a commercial pad in terms of
removal rate, average coefficient of friction and average pad leading edge
temperature. Theoretical examination of the experimental data was performed
in order to establish the mechanical and chemical contributions to the
process. A novel 3-step model, in combination with a previously developed
Flash Heating (FH) temperature model, was proposed for copper CMP. This
model presented a new expression to characterize the rate of oxide growth
and the addition of a third step to characterize the dissolution rate of
copper oxide. (PDF) |
| Feb. 8 |
Hosts: Paul McIntyre,
Deputy Director, Geballe Lab for Advanced Materials, Materials Science and
Engineering, Stanford University, and Krishna Saraswat, Professor,
Engineering and Science Institute, Stanford University
Presentation by: Dr. Wilman Tsai, Senior Program
Manager of Technology Manufacturing Group, Intel Corporation
Title: "Challenges and
Opportunities of Emerging Nanotechnology for Future Electronics
Applications"
Abstract: The
continual Si CMOS device scaling according to Moore’s law will need
revolutionary channel material beyond Si past 22 nm node in year 2013-2019.
Potential candidate are carbon nanotubes (CNT), semiconductor nanowires, Ge
and III-V materials, for future high-speed and low-power computation
applications These materials, in general, have significantly higher
intrinsic mobility (either higher electron or hole mobility) than Si, and
they can be potentially used to replace Si as the channel of the transistor
for very high speed applications. Both CNT and semiconductor nanowires are
formed using “bottom-up” chemical synthesis, and they currently suffer from
the fundamental placement and positioning problem. On the other hand, Ge and
III-V materials can be patterned into desirable device structures using
conventional “top-down” lithographic and etch techniques. Ge exhibit 15-30x
higher hole mobility and III-V materials have ~50-100x higher electron
mobility than Si, The objective of this paper is to highlight the various
opportunities and fundamental technological challenges of Ge and IIIV
Nanoelectronics, for potential future high-speed and low-power logic
applications. (PDF) |
| Feb.
22 |
No
TeleSeminar - 11th Annual ERC Review Meeting, Tucson AZ |
| March 8 |
No
TeleSeminar |
| March 22 |
Host: Farhang Shadman,
Chemical and Environmental Engineering, University of Arizona
Presentation by: Raymond A. Sierka, Professor Emeritis,
Department of Chemical and Environmental Engineering, University of Arizona
Topic Title:
“Activated Carbon-Characteristics, Performance and Regeneration”
Abstract: Activated
Carbon is the best broad spectrum adsorbent for removing contaminants from
liquid and gas streams. Commercially available activated carbons do not
perform equally. This talk will address adsorption performance as a function
of pore size and volume distribution as well as surface chemistry. Existing
manufacturing and regeneration protocols affect activated carbon properties
and performance. A newly developed Fenton-based chemical oxidation process
overcomes problems with currently employed thermal regeneration technology.
(PDF) |
| April 5 |
Host: Duane
Boning, Associate Department Head, Electrical Engineering and Computer
Science, Massachusetts Institute of Technology
Presentation by: Duane Boning, MIT
Topic:
"Modeling of
Pattern Dependencies in the Fabrication of Multilevel Copper Metallization"
Abstract: Multilevel copper metallization for ULSI
circuits is a critical technology. Topographical variations are known to
exist in copper interconnect, due to pattern dependencies in various
processes, especially copper electrochemical deposition (ECD) and
chemical-mechanical planarization (CMP). First, a physics-based chip-scale
copper ECD model is described. By considering copper ion depletion effects,
and surface additive adsorption and desorption, the plating model is able to
predict the initial topography for subsequent CMP modeling with sufficient
accuracy and computational efficiency. Second, a compatible chip-scale CMP
modeling is described. The CMP model integrates contact wear and
density-step-height approaches, so that a consistent and coherent chip-scale
model framework can be used for copper bulk polishing, copper
over-polishing, and barrier layer polishing stages. The integrated
multilevel copper metallization model is applied to the co-optimization of
the plating and CMP processes. An alternative in-pattern (rather than
between-pattern) dummy fill strategy is proposed. The integrated ECD/CMP
model is applied to the optimization of the in-pattern fill, to achieve
improved ECD uniformity and final post-CMP topography. (Duane Boning and
Hong Cai, MIT) (PDF) |
| April 19 |
Host: Srini Raghavan, University of Arizona
Presentation by: Dr. Krishna Muralidharan,
Post-doctoral research associate, Department of Materials Science and
Engineering., University of Arizona
Topic title: "Fundamental processes in megasonic-irradiated
fluids : Applications to cleaning"
Abstract: Megasonic cleaning is a traditional approach
for cleaning of photomasks and wafers. While it is believed that in the
megasonic system, two major mechanisms, namely, acoustic streaming and
cavitation are instrumental in contaminant removal, a clear picture
regarding the fundamental processes in play during the megasonic cleaning
process has not yet emerged. In this talk, we focus on characterizing the
exact role of the two mechanisms via modeling; specifically, using
continuum-level interface response theory (IRT) and atomistic-level
molecular dynamics (MD), we carefully examine acoustic streaming and
acoustic cavitation respectively, in order to develop a fundamental
understanding of the megasonic cleaning process. (PPT)
(MOV4) |
| May 3 |
Host: Jim
Watkins, University of Massachusetts
Presentation by: Tom Russell, Professor of Polymer
Science and Engineering, and Director of the NSF MRSEC on Polymers,
University of Massachusetts
Topic Title: "Nondisruptive Lithographic Processes on the
Nanoscopic Level"
Abstract: As the size scale of features continue to
shrink in devices, the use of self-assembly, i.e. a “bottom up” approach,
for device fabrication becomes increasingly important. Yet, simple
self-assembly alone will not be sufficient to meet the increasing demands
place on the registry of structures, particularly nanostructured materials.
Several criteria are key in the rapid advancement and technology transfer
for self-assembling systems. Specifically, the assembly processes must be
compatible with current “top down” approaches, where standard
photolithographic processes are used for device fabrication. Secondly,
simple routes must be available to induce long-range order, in either two or
three dimensions, in a rapid, robust and reliable manner. Thirdly, the
in-plane orientation and, therefore, ordering of the structures, must be
susceptible to a biasing by an external, macroscopic means in at least one,
if not two directions, so that individual elements can be accessed in a
reliable manner. Block copolymers, specifically block copolymers having a
cylindrical microdomain morphology, are one such material that satisfy many,
if not all, of the criteria that will be necessary for device fabrication.
Here, we discuss several routes by which these versatile materials can be
used to produce arrays of nanoscopic elements that have high aspect ratios
(ideal for templating and scaffolding), that exhibit long-range order, that
give access to multiple length scale structuring, and that are amenable to
being biased by macroscopic features placed on a surface. (PPT) |
| May 17 |
Host: James
Farrell, University of Arizona
Presentation by: Lily Liao, PhD, Research Associate,
Department of Chemical and Environmental Engineering,
University of Arizona
Topic title: "Electrochemical Water Treatment
Using Boron Doped Diamond Film Electrodes"
Abstract: In recent years there has been increasing
interest in electrochemical methods for removing both organic and inorganic
contaminants from water. This research investigated the use of boron doped
diamond film (BDD) electrodes for removing contaminants via both oxidative
and reductive processes. Electrochemical oxidation of organic contaminants
at BDD anodes is capable of mineralizing even the most recalcitrant
compounds to CO2 and H2O by a combination of direct
oxidation and indirect oxidation by hydroxyl radicals produced from water
oxidation. Electrochemical reduction can convert dissolved contaminants
into precipitates or toxic compounds into nontoxic compounds via both inner-
and outer-sphere electron transfer mechanisms. Examples on the use of BDD
electrodes for removing metals, chelating agents, chlorinated solvents, and
perfluorinated organic compounds will be presented. (PDF) |
| May 31 |
Host: Karen Gleason,
Department of Chemical Engineering, Massachusetts Institute of Technology
Presentation by: Hilton G. Pryce Lewis, Ph.D.,
President, GVD Corporation
Topic title:
"Where Are They Now? A Former ERC
Student Describes His Entrepreneurial Experiences"
Abstract:
Hilton Pryce-Lewis, a former ERC graduate student, describes the experience
of transferring technology from the lab to the commercial sector. His
company, GVD Corporation, has spent the last several years commercializing
vapor deposition technology developed by Dr. Karen Gleason at MIT. GVD’s
primary product is an ultra-thin PTFE (Teflon®) coating process which
combines all of the benefits of PTFE (lubricity, release, low-k) with a
low-temperature deposition process amenable to a wide range of substrates.
It obviates the need for solution processing and curing, and is particularly
well suited for micro- and nano-sized substrates with complex geometries.
Dr. Pryce-Lewis will discuss the technology and its benefits, and outline
GVD’s experiences and challenges in scaling up the technology, finding
markets, and raising money. New areas of interest and exploration will also
be discussed. (PDF) |
| June 14 |
Host: Anthony Muscat,
Chemical & Environmental Engineering, University of Arizona
Presentation by: Rachel Morrish, Chemical &
Environmental Engineering, University of Arizona
Topic title: Etching of Silicon Oxynitride Films in
Supercritical CO2
Abstract: Silicon oxynitride films have properties
intermediate between pure SiO2 and Si3N4, prompting their integration into a
range of advanced electronic and optical devices. In order to adequately
process and scale these devices, new etching techniques are required that
alleviate issues of pattern collapse and stiction. This study reports the
findings of a nonaqueous etching technique using an HF/pyridine complex
dissolved in supercritical carbon dioxide to remove silicon oxynitride.
Under supercritical conditions, CO2 has liquid-like densities, gas-like
diffusivities, and zero surface tension allowing it to nondestructively
penetrate nanoscale features. Supercritical CO2 based solvents offer an
additional benefit of reducing the environmental burden of processing.
Carbon dioxide is nontoxic, nonflammable, and under supercritical
conditions, can be readily separated and recycled by reducing the pressure.
The reaction in supercritical CO2 etched the silicon oxynitride film and
also formed a water-soluble, salt product layer identified as (NH4)2SiF6.
This evolving salt layer hindered the etching reaction and resulted in an
apparent reaction order less than one. A maximum etch rate of 3.1 nm/min was
found with the highest etchant concentration studied, however lower
concentrations did provide a more uniform etch and could be used for
patterning small structures. The morphology, chemical structure, and bonding
character of the (NH4)2SiF6 layer was analyzed and used to develop a
proposed reaction scheme. (PDF) |
| June 28 |
Host: Reyes Sierra,
University of Arizona
Presentation by: Victor Gamez, Department of Chemical &
Environmental Engineering, University of Arizona
Topic Title: “Non-PFOS/non-PFAS
Photoacid Generators: Environmentally Friendly Candidates for Next
Generation Lithography”
Abstract: Perfluorooctane sulfonate (PFOS) and related long
chain perfluorinated alkyl surfactants (PFAS) are vital to semiconductor
manufacturing where they are utilized in photoacid generators (PAGs),
anti-reflective coating (ARCs), and certain surfactants. Concern about the
environmental and public health impact of these compounds is increasing due
to recent reports of their world-wide distribution, environmental
persistence and bioaccumulation potential. Efforts to develop alternatives
to PFOS have focused on performance issues, and information on the
environmental compatibility of new PAGs is generally lacking. This project
aims to develop new PFOS-free (and PFAS-free) PAGs and investigate the
environmental behavior of these PFOS-free alternatives. Different PAGs
developed at Cornell University were previously shown to have excellent
photolithographic performance. Here we report on studies conducted to
characterize their environmental behavior. The PAGs were submitted to
various toxicity assays (Microtox, mitochondrial toxicity test or MTT, and
methanogenic inhibition) as well as microbial degradation tests under
different redox conditions. The results were analyzed and compared to PFOS/PFAS
PAGs. (PDF) |
| July 12 |
Host: Yoshio Nishi,
Stanford University
Presentation by: Josh Ratchford, Stanford University
Topic Title:
"Non-destructive gold removal from germanium nanowire samples"
Abstract:
Germanium
nanowire growth is readily achieved through the CVD of a germanium precursor
gas with gold nanoparticles at temperatures as low as, and in some cases,
below the bulk eutectic temperature of 360˚ C. Growth of germanium nanowires
occurs from a supersaturated liquid alloy formed from a gold nanoparticle
and germanium. Because the deep level states created by gold increases pn
junction leakage current, and often change the specific resistivity of
silicon and germanium, removal of the gold used for germanium nanowire
growth is necessary in order to fabricate reliable, high yielding, and high
performance memory from germanium nanowires. We present a non-destructive
method for removing gold from germanium nanowire samples with minimal
volumes of KI(3)(aq) solutions, measurements of the chemical state of the
germanium nanowire surface after gold removal and the effectiveness of the
gold removal procedure. (PDF) |
| July 26 |
Host: Steve
Beaudoin, Professor and Associate Head, School of Chemical Engineering, Purdue University
Presentation by:
Bum Soo Kim
and Steve Beaudoin, Purdue University
Topic title: "Electrochemical Processes on Cu Surfaces
during CMP-Relevant Time Frames"
Abstract: To understand the exact mechanisms of
chemical mechanical planarization and develop more advanced processes,
better understanding of the role of chemical reactions during polishing is
required. This work focuses on reactions on the surface of copper,
including etching and repassivation. Specifically, surface reactions on
copper in phosphoric and nitric acid-based solutions were investigated using
electrochemical tools, including potentiodynamic (PD) scans and studies of
the time-evolution of impedance at different DC potentials. PD scans were
performed in order to characterize the active/passive behavior of copper.
Different DC potentials from the active dissolution, active/passive
transient, and passive region were applied while the impedance at 100 kHz
was monitored. The open circuit potential was also studied in this manner.
Interpretations were made for the outcomes of these experiments in terms of
surface layer formation. (PDF) |
| Aug. 9 |
Host: Anthony Muscat, University of Arizona
Presentation by: Byoung Hun Lee, Program Manager,
Advanced Gate Stack Program, FEP, SEMATECH
Topic title:
"Challenges
in the gate stack technology for future semiconductor devices"
Abstract: Si based CMOS device has gone through multiple
material changes in recent technology nodes. Most recently metal electrode
and high-k dielectric have been implemented in 45nm node devices. While
there are many complications from the implementation of new gate stack
materials yet to be understood, another major challenge is approaching; the
implementation of alternative channel materials. In this talk, major
advances in the past ten year of gate stack study will be reviewed and the
gate stack research at SEMATECH will be introduced to provide insights for
the future research and collaborations. (PDF) |
| Aug. 23 |
Host: Duane Boning,
Professor of Electrical Engineering and Computer Science, Associate
Department Head, EECS, Massachusetts Institute of Technology
Presentation by: Duane Boning, Massachusetts Institute of
Technology
Topic title: "Environmentally Benign Manufacturing of 3D
Integrated Circuits"
Abstract: Environmental impact evaluation of future
technologies, before they are introduced into manufacturing, is needed in
order to identify potentially environmentally harmful materials or processes
and understand their implications, costs, and mitigation requirements. In
this work, an early assessment methodology has been applied to 3D IC
wafer-to-wafer bonding technology, motivating the exploration of process
alternatives to reduce the cost, energy, and material requirements for the
handle wafer steps. A between-die channel approach, as well as an oxide
release layer, are developed to make the handle wafer release more
efficient. In addition, a solid liquid inter-diffusion (SLID) bonding
approach using copper-indium at 200C is explored, to enable low temperature
bonding and release alternatives. (PDF) |
| Sept. 6 |
Host: David Mathine,
Assistant Professor of Optical Sciences and
Assistant Professor of Electrical and Computer Engineering, University of Arizona
Presentation by: David Mathine, University of Arizona
Topic Title: "Cell-Based
Biosensors for Toxicity Testing of New Chemicals"
Abstract: The
rapid development of new chemicals makes the current approach to toxicity
testing unrealistic since the testing relies on laborious and expensive
animal testing. One approach to increase the throughput of toxicity testing
is to use the physiological responses from cells after exposure to an
unknown chemical. Cells from the heart, kidney, prostate, liver, and other
organs can be used to test the responses to these various cell types.
Initial work has concentrated on calcium studies of cells with exposure to
TCE. TCE was chosen because it is a known toxin and can be used to verify
the sensor approach. Calcium was chosen since it is a common intracellular
messenger used in cells. Initial results were successful in showing toxic
response of heart cells. Future work will concentrate on new chemicals.
CMOS photodetectors are being developed for the sensing of fluorescent
markers. We expect that the greater sensitivity of the CMOS chip will be
able to provide efficient measurement of calcium changes and a more accurate
measurement of calcium release from the intracellular store. Recent progress
will be discussed. (PDF) |
| Sept. 20 |
Host: Ara
Philipossian, Chemical & Environmental Engineering, University of Arizona
Presentation by:
Daniel Rosales-Yeomans,
Department of Chemical and Environmental Engineering, University of Arizona
Topic Title: "Effect of Concentric Slanted Groove
Patterns on Slurry Flow during Copper CMP"
Abstract: This investigation presents the analysis of
concentric grooves with different degrees of slant for the optimization of
copper Chemical and Mechanical Planarization (CMP). Taking into
consideration the common industrial application of the concentric groove
pattern, CMP pads where prepared with concentrically grooves having
different degrees and directions of groove slant, 0° (Zero), ± 20° and ±
30°. The present study determines and explains the effect of degree and
direction of groove slant, applied wafer pressure, sliding velocity and
slurry flow rate on the overall hydrodynamics of a typical copper CMP
process by quantifying the slurry film thickness in the pad land area-wafer
region. This is done via Dual Emission UV Enhanced Fluorescence (DEUVEF)
measurements which use fluorescent dyes dissolved in the slurry to relate
light intensity to film thickness. This approach allows a better
understanding of the slurry transport on the pad surface, resulting in
process optimization through “smart” groove designs which could decrease COO
and positively affecting ESH (reduction of pad and slurry consumption).
During DEUVEF, the slurry is tagged with 2 different fluorescent dyes (Coumarin
at 0.25 g/l and Calcein at 1.00 g/l). When excited by UV, each dye emits
fluorescent light at different wavelengths. Two CCD cameras capture the
emitted light which is correlated to film thickness under the wafer via an
intensity-film thickness calibration curve. A 200-mm Fujikoshi Machinery
polisher is used for all experiments. The
film thickness measurements are taken in-situ at several wafer
pressures, sliding velocities, slurry flow rate and groove patterns (i.e.
degree and direction of groove slanting). A 200-mm quartz wafer is used for
polishing using in-situ conditioning for 30 seconds, while the CCD
cameras record slurry film thickness under the wafer. Slurry film thickness
results are compared to copper polishing data under reduced slurry flow rate
conditions for the same groove designs, indicating a possible approach to
reduced slurry consumption without compromising removal rate and possibly
defectivety. [D. Rosales-Yeomans, University of Arizona, Tucson,
Arizona, USA; H. Lee, University of Arizona, Tucson,
Arizona, USA; T. Suzuki, Toho
Engineering, Yokkaichi, Japan; A. Philipossian, University of
Arizona, Tucson, Arizona, USA] (PDF) |
| Oct. 4 |
Host: Alan West,
Department of Chemical Engineering. Columbia University
Presentation by: Kristin Shattuck, Columbia University
Topic Title: "Investigation of phosphate based electrolytes
for use during Cu-ECMP"
Abstract: The use of high down forces, abrasive slurry
particles, and strong oxides make chemical mechanical planarization (CMP)
techniques unfavorable for the future of CMOS device fabrication. The
current work is focused on studying electrochemical mechanical planarization
(ECMP) as a possible replacement or compliment to CMP. ECMP has not been
well studied and information about key factors such as electrolyte
composition, i.e., influence of additives, pad/wafer interactions,
pad/electrolyte interactions, applied electrical potential, effect of down
force, tool geometry, are crucial to understand before ECMP will be
considered for mainstream wafer processing. Our group has been
investigating phosphate based electrolytes for use during ECMP. Technical
results will highlight data obtained by our ECMP tool, as well as more
extensive electrolyte studies using microfluidic and RDE setups. Removal
rates at various applied voltages are established and the effect of pad type
is currently being investigated. Planarization results using the ECMP tool
are also being performed using a basic test structure. (PDF) |
| Oct. 18 |
Host: Farhang Shadman,
University of Arizona
Presentation by: Junpin Yao and Asad Iqbal, Chemical and
Environmental Engineering, University of Arizona
Topic Title: "Interaction of Molecular Contamination with
Surfaces"
Abstract:
Part I: With Dielectric Films
An aspect which affects the performance of integrated circuits
is the interaction of dielectric surfaces with Atmospheric Molecular
Contamination (AMC). The impact depends strongly on the nature of the
interactions between the contaminants and the dielectric surfaces. The
outgassing dynamics of IPA in BDIIX porous low-k dielectric films were
preliminary studied with Fourier Transform Infrared Spectroscopy (FTIR). A
unique set up was developed in this research for real-time and in-situ
characterization of porous low-k dielectric films. In order to study the
changes happening on the surface real-time, it is important to have a good
control of the surrounding medium and an effective purge process, otherwise
the accumulation of gas phase impurity will affect the results. The novel
design of the cell allows well controlled purging of the samples and can be
used for dynamics study. Transmission mode has been used in this study. The
results could be used to extract fundamental transport parameters such as
diffusivity and solubility of impurities in low-k films. Furthermore, the
mechanism of interactions of isopropyl alcohol (IPA) with ZrO2
film was also investigated. The results revealed that the adsorption of IPA
follows multilayer dynamics. The interaction with the bare dielectric
surface is non-dissociative and relatively weak. However, IPA chemisorbs on
a hydroxylated oxide. The isotope labeling studies revealed an exchange
mechanism in which IPA undergoes an esterification reaction with chemisorbed
H2O.
Part II: With Stainless Steel Surfaces
Electro-polished stainless steel (EPSS) tubing is widely used in
gas distribution system of semiconductor industry. Sometimes, because of
system pressure fluctuation, back diffusion and incorrect operations,
moisture concentration in gas distribution system could significantly go up
to such levels that may deteriorate manufacturing processes. A technique,
that combines measurement and process modeling, is developed to study the
dynamics of moisture absorption and desorption on EPSS surfaces. This
technique can be used to optimize the dry-down time and lower the purge-gas
consumption during system start-up or recovery, and helps in predicting
contaminants distribution with time and space in a gas distribution
network. It was revealed that how moisture back diffusion can be stopped
with minimum trickle flow at the end of laterals, the effect of system
pressure fluctuation on the change of moisture concentration, and what kind
of purge conditions (purge gas purity and purge temperature) are required to
clean a single contaminated transfer line. Meanwhile, it was found that
moisture removal from stainless steel surfaces is a slow and activated
process. (PDF) |
| Nov. 1 |
Host:
Christopher Ober, Materials Science & Engineering, Cornell University
Presentation by: Nelson Felix, Materials Science & Engineering,
Cornell University
Topic Title: "Achieving Small Dimensions with an
Environmentally Friendly Solvent: Photoresist Development Using
Supercritical CO2"
Abstract: For more than a decade the idea of using
supercritical fluids in semiconductor processing has been actively explored
by many researchers. With its low critical temperature, zero surface
tension, and non-polar inert character, supercritical CO2 (scCO2) shows
great potential for its ability to process sensitive materials with
patterned features on a very small length scale. However, barring excessive
fluorination, most materials traditionally used by industry show poor
solubility in this solvent.
This is where molecular glass resists show their unique nature. Because of
their small size, molecular glasses have the potential for scCO2 solubility
while still showing equal performance to polymer photoresists. Also,
because of their small, discrete structures, these materials also can show
lower line-edge roughness compared to traditional polymer resists. We will
demonstrate some recent successes in developing photoresist features in the
sub-65 nm range with only scCO2 as the developer solvent. Additionally, we
evaluate the effect of molecular structure on photoresist dissolution rate
and show the consequences of protecting groups and glass transition on
dissolution. These results cover a range of both positive-tone and
negative-tone systems. (PDF) |
| Nov. 15 |
Host: Reyes Sierra,
Department of Chemical and Environmental Engineering, The University of
Arizona
Presentation by: Valeria Ochoa, Department of Chemical and
Environmental Engineering, The University of Arizona
Topic Title: " Impact of fluoride on biological wastewater treatment
systems”
Abstract: Fluoride is a common contaminant in a variety of
industrial wastewaters, including semiconductor manufacturing effluents.
Industrial effluents are expected to meet stringent limits for fluoride in
order to qualify for direct discharge to publicly-owned treatment works.
The low allowable discharge limits are partly motivated by the suspected
role of fluoride as inhibitor of biological treatment processes. However,
available information on the inhibitory effects of fluoride towards
microorganisms in wastewater treatment systems is very limited. We will
present results of recent research conducted to characterize the toxic
response of fluoride towards the main microbial populations responsible for
the removal of organic constituents and nutrients in wastewater treatment
processes. In addition, results from bioassays to assess the effect of
fluoride on typical effluent biomonitoring species will be discussed. (PDF) |
| Nov. 29 |
Host: Srini
Raghavan,
Materials Science and Engineering, University of Arizona
Presentation by:
Dr. Robert
Small, RS Associates, Tucson AZ
Topic title: "BEOL Cleaning: Some Thoughts on the Coming
Challenges"
Abstract: In this presentation, Bob Small will review wet
chemical BEOL formulations currently in use in IC manufacturing companies.
He will make a critical comparison between wet and dry formulations for BEOL
cleaning, then discuss some of the challenges that are posed by newer
generation materials in terms of wetting, cleaning and drying. [Dr.
Robert Small is an active consultant for many chemical and integrated
circuit companies. Having spent many years at EKC Technology (aka du Pont-EKC),
where he headed the development of post-CMP and BEOL cleaning formulations,
Dr. Small is also an adjunct professor with the Department of
Materials Science and Engineering, University of Arizona, work closely with
Professor Raghavan.] (PPT) |
| Dec. 13 |
Host: Karen
Gleason, Massachusetts Institute of Technology
Presentation by: Nathan J. Trujillo, Department of Chemical
Engineering, Massachusetts Institute of Technology
Topic title: "Additive Patterning of Low Dielectric Constant
Polymer Using iCVD"
Abstract: As the average feature size in integrated circuits
continues to decrease, reducing the dielectric constant of the interconnect
dielectric (ILD) becomes crucial to minimizing RC delay, power consumption
and cross talk noise. The ITRS interconnect technology roadmap requires ILD
with bulk dielectric constants between 2.1-2.4 by the 40nm node and has also
set fourth materials management requirements for EHS friendly processing
which require 90% raw materials usage in low-k processing by 2011. To
accommodate this, current lithographic techniques used for dielectric
patterning must be modified to require significantly smaller volumes of
solvent. Selective deposition of patterned low-k materials is an off roadmap
approach to process step reduction, whose successful implementation is both
economically and environmentally beneficial. Initiated CVD is a low-energy,
one step, solvent-free process for producing polymeric thin films from one
or more monomer species and an initiator species. iCVD is an attractive
technique for creating low-k films from cyclic siloxane precursors, as the
low energy input helps preserve the original functionality of the monomer.
In this talk we will discuss additive patterning of
1,3,5,7-Tetravinyltetramethylcylcotetrasiloxane, a low-k monomer, using iCVD
and non-conventional lithography as a possible means of achieving
environmentally friendly dielectric processing. [Authors: Nathan J.
Trujillo and Karen K. Gleason] (PDF) |
| Dec.
27 |
No TeleSeminar
- CHRISTMAS HOLIDAY |
|
