PowerPoint Template

1
The status of academic and industrial force
metrology below 1 N and the corresponding
strategy at KRISS
TC3 Round Table Discussion Meeting Speaker
Min-Seok Kim Korea Research Institute of
Standards and Science
2
Micro- or nano mechanical testing Newton
Micro tensile testing in KRISS
Micro tensile tester (ESPI)
0.5
0.018
2
(Unit mm)
Specimen (Copper)
By courtesy of Dr. Yong-Hak Huh
3
Micro- or nano mechanical testing micro-Newton
Nanoindentation experiments in KRISS
Nanoindenter (MTS)
0.8 ?m
Specimen (ZnO thin film, 0.8 ?m)
By courtesy of Dr. Jun-Hee Hahn
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Micro- or nano mechanical testing nano Newton
Measurement of tensile properties of carbon
nanotube in KRISS
Nano-manipulator force sensor
Specimen (MWCNT)
By courtesy of Dr. Seung-Hun Nam
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Micro- or nano mechanical testing pico-Newton
Mechanical testing of stem cells in PSIA Corp.
(AFM company)
Force-Distance curve of the stem cell
Atomic force microscope (PSIA)
Adhesion effect between tip and sample Step
force 300 pN
Youngs modulus of the stell cell from the F-D
curve 10 18 kPa
Specimen (embryonic stem cell)
By courtesy of Dr. Sang-Jun Cho
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Problems due to the lack of force traceability
(1)
Youngs modulus measurements in AFM
Different cantilever
Same specimen
Data by courtesy of Dr. Sang-Jun Cho, PSIA Corp.
For the reasonable data Needs Force Calibration
or Stiffness Calibration!
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Problems due to the lack of force traceability
(2)
Mechanical testing of Spacers for TFT-LCD
display panels
60
MTS (L.R. 4.5 mN/s)
50
B company (L.R. 4.4 mN/s)
40
Load (mN)
30
Loading
Schematic diagram of a TFT-LCD panel
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Unloading
Flat Punch Tip 40? x 40?
10
0
0
100
200
300
400
500
600
700
800
Displacement (nm)
Load-displacement diagrams of the same
spacer from two different indentation instruments
Testing setup
By courtesy of Dr. Jun-Hee Hahn
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Status in KRISS AFM cantilever calibration
Nano Force Calibrator

• Calibration of micro cantilevers and force
  sensors
• Uncertainty evaluation reported (Metrologia,
  Vol. 43, pp. 389-95)
• Force measuring capability of the balance below
  10 ?N is under test
• Calibration service will be available next year

Spring constant calibration of a rhombus-shaped
cantilever that is specially designed for
mechanical testing in AFM
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Status in KRISS Transfer standards
Nano Force Sensor

• Piezoresisitive cantilever to be used as
  transfer standards
• Sensor properties are under test
• Developing force balancing cantilevers is
  scheduled next year

PCB pad
Gold wires
Force sensor
Fabricated piezoresistive cantilever
Sensor assembly
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Status in KRISS New standards
Quantized force realization in pico-and
femto-Newton range

• Based on magnetic flux quantization of a
  superconducting annulus
• Step size 0.2 pN (at 10 T/m) range 0.2 - 40
  pN
• Target uncertainty less than 1
• Project launched in 2006

Visit us in poster session for details
Magnetic moment steps (n 0,1, 2)
400 um 4 um 0.34 um
Superconducting loop or SQUID
Super-currents
Ultra-soft cantilever
Stepwise force
Optic interferometer
z-gradient magnet
Fabricated ultra-soft cantilever
F n ? 184 fN
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Small force standards development strategies
Applications
Micro thrusters for satellites
Magnetic resonance force microscope
Nano indentation
Optical tweezer
Micro mechanical testing
Nano mechanical testing based on AFM
1 aN
Force
100 N
1 N
1 mN
1 ?N
1 nN
1 pN
1 fN
Quantized magnetic force
Electrostatic force
Deadweight force
Standard
10 ?N
10 pN
Realization
Nano-balance
Electromagnetic compensation balance
Superconducting ring
10 N
Superconducting ring
Nano Force Calibrator
Ultrasoft cantilever
5 N
50 mN
Magnet for z-gradient
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Closing Remarks

• Industrial needs for traceable small force
  metrology will be emerging
• However, when ??
• What would be the uncertainty level of small
  force metrology which
• industries require ?
• Accurate force metrology would be a solid
  foundation of reliable and
• high-qualified production of
  nanotechnology-based goods