Transcript LOW TEMPERATURE PLASMA STUDIES AND APPLICATIONS

LOW TEMPERATURE PLASMA
STUDIES AND APPLICATIONS
Xiaogang Wang
Dalian University of Technology
OUTLINE
Relationship with Industry
Major Applications
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Plasma Sources
Beams
Pulsed Power Technology
Atmospheric Pressure Discharge
Plasma Etching
Dusty Plasma Applications
Biophysical Applications
Discussions
RELATIONSHIP
WITH INDUSTRY
Basic structure (USA)
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Basic researches (government support)
Industry R & Ds (Private sectors)
Industry
 Sources & Beams, Processing, Films,
Electronics, Computer, etc.
Current structure in China
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Basic researches (government support)
Industry R & Ds (none)
Industry applications (???)
Basic researches (in US)
Pure scientific researches
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What is going to happen in 20 years?
 Such as: computer beyond silicon
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Basic physical, chemical, biological processes
“Basic” applied researches
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New sources, new ways, new materials
 Such as: helicon in 90s, sources & beams for “big
science” , PSII in 80s, pulsed tech, OAPUGD
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Computer codes
Basic researches (in China)
Pure scientific researches
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What is going to happen in 20 years? (??)
Basic physical (Yes), chemical (?),
biological (?) processes
“Basic” applied researches
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New sources, new ways, new materials (?)
Computer codes (??)
Industry R & Ds (in US)
New sources, new ways, new materials
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Overlap with basic researches, more profitoriented
Computer codes
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Overlap with basic researches, more specific
New processes
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Very detail improvements
Industry R & Ds (in China)
State sectors
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Government R & D
 Wealthy & weak, but unwilling to share resource
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State owned industry
 In bad shape itself, no enough resource
Private sectors
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“Publicly traded”: strongly rely on import
Privately owned: limited resource and vision
Industry in US
High tech leaders
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Computer chips
New materials
Medical and biological applications
Government sectors
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Aero-space industry &
Environment industry
Big sciences
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Reactors and Beams
Sources
Industry in China
Not a leader
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rely on import
Not a major manufacturer in high tech
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Japan: at least need process improvement
China: small size, low-end, no such needs
Government
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Separation of funding and human resources
Big sciences
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Limited
INDUSTRIAL APPLICATIONS OF PLASMAS
Surface Treatment:
Ion implantation, hardening, Welding, cutting, drilling
Film deposition
Volume Processing:
Flue gas treatment, Metal Recovery, Waste Treatment
Water purification, Plasma spraying
Light Sources
High Intensity, Discharge Lamps, Low Pressure Lamps,
Specialty Sources,
Lasers, Field-Emitter Arrays, Plasma Displays
Switches:
Electric Power, Pulsed Power
Energy Converters:
MHD Generators, Thermionic Energy Converters, Beam
Sources
Radiation Processing:
Ceramic powders, Plant growth
Medicine:
Surface treatment, Instrument Sterilization
MAJOR APPLICATIONS
Plasma Sources
Beams
Pulsed Power Technology
Atmospheric Pressure Discharge
Plasma Etching
PLASMA SOURCES
Helicons
ECRs
ICPs
Magnetrons
Gyrotrons
Thrusters
GEC reference reactors
GEC Reactor
Gaseous Electronics Conference (GEC)
Reference Reactor (Hargis et al, 1991)
Capacitive coupled plasmas
RF discharge (13.56 MHz, ~100 V)
Detailed computer simulation code
GEC Reactor:
Basic parameters
Rc = 5 cm
Rr = Ra = 5.25 cm
RT = 10 cm
Xc = Xr = 3.5 cm
Xa = 6.25 cm
XT = 10 cm
d = Xa-Xc = 2.75 cm
BEAMS
Laser beams
Ion beams
Electron beams
Energetic particle beams
Ion beams:
Plasma focusing
Off–focus of charged particle beams
Plasma focusing
Applications to microelectronics
“Nano” microelectronics:
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Quantum Ge/Si dots
Growth by molecular beams + electron
beam evaporators for Si and Ge deposition
Enhancement by ion implantation
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Low energy As+ beam (1 keV)
Depositing current density 0.02 mA/cm2
PULSED POWER TECH
Pulsed voltage
Pulsed beams
Experiments at
Materials Modification Lab, DUT
C on Al surface
Bombarded by pulsed electron beams
Regular deposition thickness: mms
After a single pulse: ~ 1mm
Multi-pulses: Better results
Anomalous diffusion effect ?
Experiments at MMLab:
Pulsed electron beam parameters
Width:
Power:
Energy density:
~ mm
27.8 keV
3.2 J/cm2
1. Cathode, 2. Anode, 3. Target,
4. Vacuum chamber,
5. Cathode plasma,
6. Anode plasma,
7. Coils, 8. Sparks
ATMOSHERIC DISCHARGES
Arc discharges
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Circuit breakers
Plasma guns & furnaces for steel, auto and
environment industries
Surface physical simulation of re-entry
Corona discharges
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Environment industry
Glow discharges
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Filament glow discharges
OAUGD
Physical simulation of re-entry
Fluid model (electrostatic MHD)
Kink instabilities
Two stream instabilities
Numerical simulation codes
DUSTY PLASMA
APPLICATIONS
Dust particles in reactors
Removal by heart-beating waves
Removal by bipolar diffusions
Other applications
Dust particles in reactors:
Particle creations
Particle creation & growth phases
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Cluster formation
Nucleation and cluster growth
Coagulation
Particle growth
Particle creations :
Major processes
Surface processes:
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Etching
Sputtering
PECVD processes:
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Walls
Chemical polymers
Dust particles in reactors:
Impacts of particles
Surface contamination
Effects on sheath and electron density
Application of dust energetics
Particle size control and nanostrutrued thin
films
Surface contamination
Particle emission and trapping in plasma
processing reactors
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ICPs
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CCPs
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Helicons and ECRs
Effects on sheath
and electron density
Energy absorption
Electron density reduction
Dust-free processing
Dust cleaning (removal) techniques
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Magnetization and E X B drift
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Dust trajectory calculations
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Electrical potential configurations
Application of dust energetics
Dust energetics
Heavy particle deposition
“Dust-enhanced” PECVD
Dust charging and distribution studies
Dust size control and
nanostructured thin films
Opto-electronics applications of nanostructure thin films
Nano-crystallite with dusty plasma
technology
BIOPHYSICAL APPLICATIONS
Electroporation
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Drug delivery and gene therapy
Seed modification (ion & plasma beams) ?
Surface sterilization
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Anti-bioterrorism application
Medical and other industry applications
Surface modification
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To artificial organs etc.
High power, low duty circle pulses
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Applications to biological systems
Electroporation:
Basic processes
Applying short electrical pulses
Charging of lipid bilayer membranes
Fast local structure rearrangement
Transition to “pore” stage
Tremendous enhancement of ionic and
molecular transport
Possible candidate for seed modification?
Electroporation:
Basic parameters
Pulse width:
Pore creation period:
Pore relaxation time:
Pore radii:
Bilayer thickness:
Membrane voltage:
Electrical field:
~
~
>
~
~
>
~
ms – ms
ms
1s
nm
mm
1V
kV/cm
Surface sterilization:
Anti-bioterrorism application
Large scale anthrax outbreak
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Soviet Union, 1979 (Science 266, 1994)
USA, 2001
Plasma sterilization for large areas
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No damage to the surface
Fast cleanup: > 10cm/s
In-place agent destruction, no hazard waste
Tools
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Montec steam plasma torch
TTU arc-jet thruster
Surface sterilization:
Plasma parameters
Power:
Work plasma:
Temperature:
Threshold:
Rate
Kill rate:
60 – 100 kW
Water steam &
> 1500 K
> 3000 K
> 10 cm/s
> 80 %
DISCUSSIONS
Plasma cloaking
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Drag-reduction and EM waves absorption
Plasma shock formation and its effect
Plasma etching
Plasma chemistry
University Research Centers in US
UW-UM Center for Plasma Aided
Manufacturing
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Research Areas:
 Thin Film Deposition
 Thick Film Deposition
 Plasma Etching
 Surface Modification
Thin Film Deposition
Plasma-mediated, surface modification of
organic and inorganic polymeric substrates
for generating controlled etching reactions,
creating specific surface topographies, and
implanting specific functionalities onto
various substrate surfaces.
Deposition of novel and conventional
macromolecular layers (e.g. Teflon-like thin layers
and IR transparent films) on inorganic and organic
surfaces by involving plasma-state and plasmainduced reaction mechanisms, including template
polymerization reaction mechanisms initiated from
surfaces with plasma-enhanced crystallynity.
Investigation of the influence of plasma parameters
(electron energy distribution, power, frequency,
pressure, etc.) on the discharge-induced gas phase
molecular fragmentation and surface-mediated
plasma-chemistry mechanisms
•Kinetic modeling of plasma-induced gas phase
fragmentation and gas phase and surface-mediated
recombination processes (e.g. Kinetic modeling of
ammonia and hydrazine-RF plasma environments).
•Generation of intelligent substrates for molecular
recognition and molecular machining processes by
immobilizing and synthesizing active biomolecules
(e.g. enzymes, oligonucleotides) on plasmafunctionalized substrate surfaces
•Evaluation of the influence of the amorphous and
stereoregular nature of the polymeric substrates and
the chemical nature and length of spacer molecules
on the activities of the immobilized biomolecules.
•Development of novel plasma installations for
specific plasma treatments, and for scaling up
laboratory technologies to industrial applications
Thick Film Deposition
A) Plasma spraying:
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* Nozzle and shroud development and
evaluation for increased plasma jet stability,
and improved deposition efficiency and
consistency of coating quality.
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* Development of sensors and control
algorithms for detecting and avoiding variations
in plasma jet behavior and coating quality.
B) Wire arc spraying:
•* Spray pattern control through different nozzle
and shroud designs.
•* Development of fundamental process
correlations using process models and
advanced diagnostics with a novel torch.
•* Application of novel control algorithm based on
computer analysis of arc
voltage traces.
•C) Thermal plasma CVD:
•* Texture control during high rate diamond film
deposition through detailed understanding of the
boundary layer chemistry based on modeling and
diagnostics using gas chromatography.
•* Arcjet deposition at high rates of hard, boron
containing films.
Plasma Etching
Etch Tool Development
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Helicon plasma etching
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Magnetically enhanced inductively coupled
plasmas (ICP)
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Large area substrates
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Modeling
Semiconductor Processing:
* Fluorocarbon-based SiO2 etching - chemical
characterization of gas phase using infrared
spectroscopy, endpoint detection, etch
selectivity/ion energy control at the wafer surface
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* Plasma-Induced Damage - surface charging
effects in device damage and feature profile
evolution, discharge modulation for reduction of
charging-induced damage, vacuum ultraviolet
radiation damage
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* Real-time Control of Plasma Etching - efforts
includes development of sensors (e.g., wall
deposition monitor), and control strategies
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Advanced Plasma Etch Diagnostics
Diagnostics currently under development:
Langmuir probe theory in magnetized plasmas
Infrared absorption spectroscopy
Electro-optical probe
Recent collaborations with industrial partners
•Process development for polymer etching
•Surface charging reduction during plasma etching
•Process development for etching of magnetic
materials
•Chemical characterization of plasmas for
fluorocarbon-based etching of SiO2
Thank you!