nano overview top-down approach prasad - portland...
TRANSCRIPT
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Shalini Prasad, Ph.D.Department of Electrical and Computer EngineeringBiomedical Micro devices and Nanotechnology Lab
Portland State University
BIOMEDICAL MICRODEVICES ANDNANOTECHNOLGY LAB
The Top-Down Approach to Nanotechnology
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Theme
Micro/NanoSensors and
Devices
Carbon nanotubes
Lemay et. al. Nature, 412 (2001) 617
CdSe
ZnS
Quantum Dots
Yamaguchi et. al. Nature.Mat. 3, (2004) 337Porous Alumina
Belcher et. al. Science 303,(2004) 213Nanowires
Bio-electronic interfaces
1
2
3
1
2
3
( )( )
Chemical Sensing Platforms
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Motivation
There is an immense need for sensors with broad based broad based detection capabilitydetection capability, rapid response timesrapid response times, automation automation capabilitycapability, and portabilityportability.Over the past 10 years, there has been growing interest in the use of nanomaterial as sensors in environmental, medical, toxicological, and defense applications.Nanomaterial improve the 3 R’s –reliability, reproducibility reliability, reproducibility and robustnessand robustness of the sensor due to improved surface area, increased functionality and amenability towards integration with existing sensor platforms.Development of nanomaterial based sensors can be achieved in “ off-clean room” environments
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Micromachining and “Soft” Fabrication
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Micromachining Materials
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
“Soft” Fabrication Materials
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Bulk Micromachining
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Surface Micromachining
Courtesy: Fatikow and Rembolt 1997
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Mask Creation
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Silicon Wafer Preparation
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Thermal Silicon Oxide
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Thermal Silicon Oxide Methods
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Spin Casting Resist
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Resist Types
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Photolithography Process
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Photoresist Types
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
UV-Exposure at 350-400 nm
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Developing the UV Exposed Wafer
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Etching Methods
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Etching Profiles
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Dry Chemical Etching: Reaction Mechanisms
Courtesy: M.Madou, Fundamentals of Microfabrication
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Dry Chemical Etching: Loading effects- bull’s eye
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Dry Chemical Etching: Ion energy vs. Pressure
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Reactive Ion Etching
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Physical Sputtering
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Sputter Yield
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Resist Stripping
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Profilometry
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Profilometry Graph
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Energy, Vacuum and Directionality
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
“Soft” Lithography
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
PDMS Lithography (Silicone)
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Micro contact Printing (μCP)
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Micro Transfer Molding (μTM)
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Micro molding in Capillaries (MIMIC)
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
“Smart” Polymers and Hydrogels
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Microelectrode
Array
Technology
(MEA)
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Si
A. PECVD Silicon Nitride Deposition4
Si
Si3N4
-B. E beam Platinum Deposition Pt
C. Photoresist Patterning
D. Platinum Etching
E. Photoresist Removal
Planar Microelectrode ArrayFabrication Sequence
S.Prasad, et. al. J.Biomed.Microdevices.5(2), (2003) 125
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
40 μm
Prototypes of Microelectrode Arrays that Function as Analysis Platforms
200 μm
2x2 platinum MEA with fibronectinpermeation layer used for cell morphological studies
3x3 platinum/titanium MEA used for environmental sensing applications.
5x5 microelectrode array comprising of platinum electrodes used for sensing and diagnostic applications.
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Determination of Electrical Field Distribution on a Microelectrode Array
Electric field distribution on a 4x4 section of the microelectrode array in the absence of micro particles
Electric field distribution on a 4x4 section of the microelectrode array in the presence of micro particles 20 μm in diameter with a surface charge of -25mV
Min
MaxStrength (V/m)
Electrode
Min
MaxStrength (V/m)
ElectrodeParticle
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Manipulation
Of
Micro particles
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
80 μm
20 μm
0V Peak to Peak
Optical micrograph of a section of the 10x10 microelectrode array comprising of platinum electrodes 80 μm in diameter with 200 μm center-to-center spacing. The geometry of the design allows positive dielectrophoretic traps to develop over the electrodes.
Initial random dispersion of 10 μm Polystyrene beads. The beads are functionalized (negatively charged to mimic the membrane of biological cells) in sodium dodecyl sulfate detergent-deionized water solution (SDS). The beads after several wash cycles are re-suspended in detergent free medium
Bead Assembly
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
1V peak to Peak 1.2 kHz
20 μm
80 μm
1V peak to Peak 1.2 kHz
Negative Dielectrophoresis- Bead Congregation away from electrode edges in regions of low electric fields
Polystyrene beads have lower polarizability as compared to the suspenion medium and get localized are regions of low electric field at the specified parameters
The concentration of the beads is 10000 beads/ml. Visualization magnification:8x
Visualization magnification: 2.5x
Equipment: Microzoom Optical Probe Station
Bead Assembly as a Cell Patterning Model
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
1.2V peak to Peak 3.8 kHz
20 μm
Positive Dielectrophoresis- Bead Congregation towards electrode edges in regions of high electric fields
Polystyrene beads have higher polarizability as compared to the suspension medium and get localized are regions of high electricfield at the specified parameters
Visualization magnification: 8x
Bead Assembly as a Cell Patterning Model
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Separation and Positioning of Bio-particles
Neurons-Positive and Negative Dielectrophoresis
Neurons
Glial Cells
S.Prasad, M. Yang, X. Zhang, C. S. Ozkan and M. Ozkan, Journal of Biomedical Microdevices, 5(2)(2003) 125
(A) Random deposition of neurons on electrodes before the application of AC fields, (B) Patterned arraying of neurons on electrode edges on applying an AC field of 8Vpp at 4.6 MHz due to positive dielectrophoresis, (C) Movement of neurons away from electrodes due to negative dielectrophoresis
80 µm80 µm80 µm80 µm80 μm80 μm
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Cell Sorting
Problem Statement:Problem Statement: Separate a specific cell type from a hybrid mix based on variations to dielectric properties, surface charge and size for a specific cell type.
Current Technological Limitations:Current Technological Limitations: Reproducibility, Speed of separation, volume of separation.
Solution:Solution: Integrate electric field effects in the micro scale to achievesorting
Goal:Goal: Separation with purity ~> 95%
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Sorting Platforms
Planar, angular micro electrode array arrangement for generating point field effects
Process involving cell isolation and separation
A
20 μm
B
20 μm
BIOMEDICAL MICRODEVICES & BIOMEDICAL MICRODEVICES & NANO LABORATORYNANO LABORATORY
Summary
Top down fabrication for micro and nanodevices using wet and dry micromachining techniques and nanomaterial integration.Silicon and soft lithography techniquesCombination of the two techniques are essential for device developmentMicro scale platforms base for both micro and nanodevicesApplications: Bead assembly, Cell sorting platforms, Drug testing platforms, Biochemical sensors