SRC Engineering Research Center for Environmentally Benign Semiconductor Manufacturing (ERC)

                                                          **  Bringing Sustainability to Semiconductor Manufacturing **

A multi-university research center leading the way to environmentally friendly semiconductor manufacturing, sponsored by the Semiconductor Research Corporation's Global Research Collaboration (GRC) Research Program
 




 

 

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- 2016 / 2017 -
  If you are interested in additional presentation information, contact Karen McClure:  kmcclure@erc.arizona.edu
 
Jan. 7, 2016 Host:  Paul Pantano, University of Texas-Dallas
Guest speaker:  
Dr. Brenner is a preventive medicine and public health physician at the SUNY Polytechnic Institute Colleges of Nanoscale Science & Engineering (CNSE)
Topic title:
Implications of Nanotechnology on Human and Environmental Health
Abstract:
The rapid growth and projected acceleration of nanotechnology creates urgency in understanding, predicting, and managing the potential health risks associated with occupational, environmental, and consumer exposures to nanomaterials. Dr. Brenner’s research integrates occupational and environmental medicine, exposure science, industrial hygiene, materials science, and metrology to investigate the potential human health and safety implications of exposure to engineered nanomaterials. The goal is to proactively address the emerging needs of health and safety research related to engineered nanomaterials, seeking to develop in real-time the innovative technologies and methodologies needed to assess, monitor, and safely accelerate nanotechnology R&D worldwide. Some of her ongoing research projects include exposure assessment to help define occupational and environmental exposures to engineered nanoparticles in real-world scenarios. These projects include assessing worker exposure to engineered nanomaterials during semiconductor manufacturing, determining the fate of nanoparticles in conventional wastewater treatment processes, and measuring the efficacy of control measures in preventing occupational exposure to engineered nanoparticles.  Exposure assessment data informs realistic dosing models and regimens for related nanotoxicology research efforts to help define hazards using cell and animal models.
Bio (Sara Brenner, MD, MPH)
:
Dr. Brenner is a preventive medicine and public health physician at the SUNY Polytechnic Institute Colleges of Nanoscale Science & Engineering (CNSE), serving as the Assistant Vice President for NanoHealth Initiatives and an Assistant Professor of Nanobioscience.  Her research and initiatives aim to develop novel nanotechnology applications in the life sciences, including medicine and public health. Dr. Brenner is leading health and safety research initiatives related to nanoparticle and nanomaterial exposures in the workplace, consumer marketplace, and environment. She is Chair of the steering committee for the NanoHealth and Safety Center at CNSE, a public-private partnership that is addressing gaps in our understanding of the safety and risk associated with the unique characteristics of nanoscale materials. Her research team incorporates theory from many disciplines such as physics, engineering, biology, genetics, medicine, public health, epidemiology, industrial hygiene, and environmental science to advance risk assessment and reduction strategies for occupational exposures, monitoring of materials that may impact population health and public safety, and the development of industrial practice standards for product safety. She is also the CNSE Program Director of the MD/PhD program in medicine and nanoscale science or engineering, a program that she helped co-found with SUNY Downstate Medical Center. It is the first dual-degree clinical training program in nanomedicine that aims to produce a new, hybrid generation of physician researchers. Dr. Brenner is both personally and professionally dedicated to health and wellness and practices what she preaches by participating in fitness events including road, trail, and snowshoe races ranging from 1 km sprints to 50 mile ultramarathons. She is the recipient of the Albany-Colonie Chamber of Commerce Women of Excellence Award 2012 (Emerging Professional).  Brenner Research Team website: https://sunypoly.edu/research/team-brenner/ 
 
Feb. 4 Host:  Anthony Muscat, Chemical and Environmental Engineering, The University of Arizona
Presented by:   James Lawrence Hackett IV, Chemical and Environmental Engineering, The University of Arizona
Topic title:  Investigation of Speciation in III‐V Wet Etching to Mitigate Hazardous Product Formation” 

Abstract
:  As semiconductor manufactures continue to look into the possible roles of III-V materials, more work is needed to determine the environmental and health impacts of large scale manufacturing. This work aims to measure this impact by taking a mass balance approach, looking at the speciation across liquid, gas, and solid phases. The analysis will be guided by thermodynamic software: Phreeqci and STABCAL. To demonstrate the mass balance, experiments consisting of wet etching GaAs (100) in 0.03% (v/v) HF were performed. The etching resulted in a Ga:As molar ratio of 100:1 in the aqueous phase using ICP-MS. Under these conditions, it is possible that AsF3 is forming and then leaving the solution. Also, a STABCAL demonstration shows the construction of potential-pH diagrams for citric acid systems.
 
Mar. 3 Host:  Shyam Aravamudhan, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University and University of North Carolina at Greensboro
Presented by:  Steven Crawford, Graduate Student, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University and University of North Carolina at Greensboro
Topic title: "
Update on Physicochemical Characterization and Toxicity Analysis of Spent CMP Waste"
Abstract:  This talk will report on the current progress in understanding of physicochemical characteristics and preliminary toxicity of pristine CMP slurries and spent CMP waste following polishing of GaAs and HDP oxide films. GaAs and HDP oxide films were polished under different CMP conditions using slurries containing colloidal or fumed silica nanoparticles. 
 
April 7 No Seminar -- ERC Review Meeting
May 5 Host:  Jane Chang, Department of Chemical and Biomolecular Engineering, University of California-Los Angeles
Presented by:  Jane Chang, University of California-Los Angeles
Topic title:
  "The Challenges and Opportunities of Atomic Layer Etching"
Abstract
The introduction of new and functionally improved materials into silicon based integrated circuits is a major driver to enable the continued down-scaling of circuit density and performance enhancement in analog, logic, and memory devices.  Many new materials, such as multiferroics, magnetic materials and phase change materials, are much harder to pattern, thereby posing significant challenges to the design and selection of plasma etching chemistry.  While ion milling is effective in patterning some of these functionally improved materials, such as complex magnetic material stacks used in magnetic tunnel junctions, it limits the scalability and integration of devices.  These challenges point to the growing needs of identifying and developing viable etch chemicals and processes that are more effective in patterning complex materials and material systems. 
     In this talk, a generalized approach based on combined thermodynamic assessment and kinetic validation is presented to identify and validate the efficacy of various plasma chemistries.  Specifically, potential reactions between the dominant vapor phase/condensed species at the surface are considered at various temperatures and reactant partial pressures.  The volatility of etch product was determined to aid the selection of viable etch chemistry leading to improved etch rate of reactive ion etching process.  Based on the thermodynamic screening, viable chemistries are tested experimentally to corroborate the theoretical prediction.  Some of the above mentioned material systems such as magnetic materials used in magnetic tunnel junctions are used as examples to demonstrate the broad applicability of this approach. 
 
June 2 Host:  Paul Westerhoff, Professor in the Civil, Environmental and Sustainable Engineering Program in the School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering (FSE), Arizona State University
Presented by:  Jared Schoepf, PhD Candidate, Arizona State University
Topic title: 
“Detection of engineered nano materials in complex matrices: A case study on nano materials in Food”
Abstract
The unknowns surrounding presence, composition and transformations during the use phase of engineered nanoparticles (ENPs) in consumer products is raising human and environmental health concerns. This research developed evidence and confirmatory analytical methods to determine the presence and composition of ENPs in consumer products with a complex organic matrix. Three methods were developed to analyze three different sets of food products. Processed foods such as taco seasoning, cake powders, vitamins, and candies (N=28) were analyzed for the absence or presence of silicon and titanium dioxide. Silicon dioxide is used as an anticaking agent and texturizer while titanium dioxide is used as a white pigment. Laser Induced Breakdown Spectroscopy (LIBS) was used as a pre-screening technique with presence confirmed by transmission electron microscopy (TEM) and concentration measured by inductively coupled plasma – mass spectroscopy (ICP-MS). TEM confirmed 25 food samples with the presence of either nano silicon dioxide (aprox. 20 nm in diameter), or nano titanium dioxide (aprox. 130 nm in diameter). Vegetables and fruits (N=17) were analyzed for coatings with nanomaterial presence with scanning electron microscopy (SEM). SEM confirmed the absence of engineered nanomaterials. Baby formulas (N=6) were analyzed for nano-hydroxyapatite using x-ray fluorescence (XRF) and TEM. Nano-scale crystalline needle-shaped hydroxyapatite (HA; appx. 25 nm x 150 nm) primary particles, present as aggregates (0.3-2 μm), were detected in half the samples. Dissolution experiments with needle-shaped HA were conducted to assess potential transformations in simulated drinking water (near-neutral pH) and simulated biological fluids (saliva and acidic gastric fluids).
We conclude that LIBS or XRF alone or in combination with sample pre-treatment techniques provides a rapid, field deployable technique to detect nanomaterials in complex matrices that is faster than TEM or ICP-MS analysis. This approach will aid human exposure assessments to food products but could also be applied to swabs, fabrics, or biological fluids or tissues to rapidly screen for potential nanomaterial exposure.
 
July 7 No Seminar
Aug. 4 Host:  Rockford Draper, Ph.D., Department of Biological Sciences, University of Texas-Dallas
Presentation by
Vasanth Murali, Ph.D., Department of Biological Sciences, University of Texas-Dallas
Topic title:  "The Impact of Subcellular Location on the Near Infrared-Mediated Thermal Ablation of Cells by Targeted Carbon Nanotubes"
Abstact
Single-walled carbon nanotubes (SWNTs) are used in the near infrared (NIR)-mediated thermal ablation of tumor cells because they efficiently convert absorbed NIR light into heat. Despite the therapeutic potential of SWNTs, there have been no published studies that directly quantify how many SWNTs need be associated with a cell to achieve a desired efficiency of killing, or what is the most efficient subcellular location of SWNTs for killing cells normalized to the dose of SWNTs in that location. Herein we measured dose response curves for the efficiency of killing correlated to the measured amounts of folate-targeted carboxylated SWNTs that were either on the surface or within the vacuolar compartment of normal rat kidney (NRK) cells. The SWNT subcellular locations were verified using Raman imaging of SWNTs merged with fluorescence imaging of known subcellular markers. The dose response curves revealed that 3.5 pg/cell of SWNTs confined to the cell surface had little effect on cells upon NIR irradiation under the standard conditions used. However, when 3.5 pg/cell of SWNTs were internalized within endosomal/lysosomal compartments, ~50% of the cells were killed after NIR exposure. To our knowledge, this is the first time that SWNT amounts at known subcellular locations have been correlated with a dose-normalized efficacy of thermal ablation and the results support the idea that SWNTs confined to the plasma membrane are not as effective in NIR-mediated cell killing
as an equivalent amount of SWNTs within the endosomal/lysosomal vesicles.
 
Sept. 1 Host:  Farhang Shadman, Chemical and Environmental Engineering, University of Arizona
Presented by:  Prof. Roberto Guzman, Chemical and Environmental Engineering, University of Arizona
Topic title:
Synthesis and Study of Chelating Polymers and Their Application to Metal Ion Separations: Regenerable Chelating Adsorbents for Effective Removal of Arsenic from Aqueous Solutions
Abstract:
 In this presentation, we will describe the use of derivatives of polyethylenimine (PEI)-polymer-chelates and their use as new chelating hydrogels for metal ion separations. Metal ions, being electrophiles, have propensity to combine with nucleophiles to form metal complexes. The chelated metal ions serve as selective adsorption centers for specified nucleophiles used here for the synthesis of reversible and regenerable arsenic adsorbents. The significance of this method is that there is no need for disposal of the adsorbent since this new media can be re-generated indefinitely without a decrease in their capacity or effectiveness. In this approach, a modified polymer (a chelating branched carboxylated polyethylene-imine, CM-PEI) with high capacity for metal ions (e.g., Fe(III), Cu(II)) is attached covalently to a solid matrix. Once the Fe(III) ion is chelated, as an example, the immobilized metal has high affinity and high capacity for arsenate ions. The adsorbed arsenic is desorbed from the column by simply decreasing the pH of the eluant solution and recovered in a highly concentrated form. In this case however, the adsorbent column remains intact and can be regenerated and there is no need to dispose of the media in a landfill. Once the column is re-equilibrated with iron at an appropriate pH (now as a regenerated adsorbent) it is ready again to start a new arsenic adsorption-desorption cycle. The mechanism of adsorption in this proposed case is the same mechanism involved in the adsorption of arsenic by iron-based oxide systems, the most common adsorption of arsenic technique used and recommended by the EPA, but in our scheme, the process of adsorption is reversible and thus the adsorbent regenerable.
 
Oct. 6 No Seminar >> ERC-SRC Mid-Year Review (WebEx)
Nov. 3 Host:  Anthony Muscat, Dept. of Chemical and Environmental Engineering, University of Arizona
Presented by: Adam Hinckley, Ph.D. Student, Dept. of Chemical and Environmental Engineering, University of Arizona
Topic title: "Closing Mass Balances Through Speciation of III-V Etching Products"
Abstract:
III-V materials offer a pathway to advancing finFET device development because they possess higher carrier mobility than Si or Ge. Wet chemical cleaning and patterning of III-Vs produces soluble species that can remain in the liquid phase, become solids or evaporate as gases. Because etching products contain such elements as As, In, and Sb, they can pose serious health risks during industrial wafer processing. Gas phase species were measured using a mass spectrometer system designed to sample vapor at atmospheric conditions. Gas phase species were detected above inorganic solutions used to etch GaAs, SiO2, and InP.  Using the detected signal for N2 as a reference, the total concentration of As in the gas phase above 49 % (v/v) and 1% (v/v) aqueous HF solutions was calculated to be approximately 2 ppm and 1 ppm, respectively. Using the concentration calculated above 1 % (v/v) HF, an As mass balance can be closed to within approximately 1 nmol. Additional work will focus on closing mass balances to improve our understanding of III-V etching mechanisms and identify safe industry-scale processing conditions.
 
Dec. 1 Host:  Shyam Aravamudhan, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University
Presented by
Steven Crawford, Graduate Student, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University and University of North Carolina at Greensboro
Topic title
"Update on characterization and toxicity studies with bound (as composite filler) and unbound nanoparticles (in CMP slurry)"
Abstract
This talk will provide an update on studies performed to understand the physical and chemical characteristics of (a) composite filler material, namely boron nitride nanoparticles before and after thermal degradation and (b) pristine slurries and spent CMP waste after polishing of GaAs and HDP oxide films. Next, we will discuss our preliminary determination of half maximal inhibitory concentration (IC50) from the dose-response curves with both pre- (pristine) and post (transformed) nanoparticles.
 
Jan. 5, 2017 Happy New Year! No Seminar
Feb. 2 Host:  Paul Westerhoff, Professor in the Civil, Environmental and Sustainable Engineering Program in the School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering (FSE), Arizona State University
Presented by:  Michael Simonich, Ph.D., Faculty Research Associate, Sinnhuber Aquatic Research Laboratory, Oregon State University
Topic title"Using Multidimensional Zebrafish Data to Advance Environmental Health"
Abstract
Some environmental exposures to chemicals, drugs, and nanomaterials negatively impact human and environmental health. The toxic entities interact with “genomes” to cause harm. We can use high throughput in vivo bioactivity assays to identify all hazardous agents. Phenotypic anchoring of structures to omics results can be used to identify the “targets” of these chemicals. Using structural and mechanistic information we can predict the toxicity of novel materials, so it should be possible to proactively design inherently safer products.

 
Thursday
Feb. 2, 2017
Host:  Paul Westerhoff, Professor in the Civil, Environmental and Sustainable Engineering Program in the School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering (FSE), Arizona State University
Presented by:  Michael Simonich, Ph.D., Faculty Research Associate, Sinnhuber Aquatic Research Laboratory, Oregon State University
Topic title"Using Multidimensional Zebrafish Data to Advance Environmental Health"
Abstract
Some environmental exposures to chemicals, drugs, and nanomaterials negatively impact human and environmental health. The toxic entities interact with “genomes” to cause harm. We can use high throughput in vivo bioactivity assays to identify all hazardous agents. Phenotypic anchoring of structures to omics results can be used to identify the “targets” of these chemicals. Using structural and mechanistic information we can predict the toxicity of novel materials, so it should be possible to proactively design inherently safer products.
Thursday
March 2, 2017
 
Host Reyes Sierra, Professor, Chemical and Environmental Engineering, University of Arizona
Presented by:  Chao Zeng, Ph.D., Chemical and Environmental Engineering, University of Arizona
Topic title:  TBP
Abstract:
 

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