• Polymer(Korea)
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• v.30 no.3
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• pp.187-195
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• 2006

Atomic force microscope (AFM)-based anodic oxidation lithography has gained great in forests in fabricating nanometer scale features on semiconductor or metal substrates beyond the limitation of optical lithography. In this article AFM anodic oxidation lithography and its organic resist layers are introduced based on our previous works. Organic resist layers of self-assembled monolayers, Langmuir-Blodgett films and polymer films aye suggested to play a key role in enhancing the aspect ratio of producing features, the lithographic speed, and spatial precision in AFM anodic oxidation lithography.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.167-177
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• 2013

원자 힘 현미경(Atomic Force Microscopy, AFM) 탐침과 표면 사이의 좁은 틈에서 형성되는 나노미터 크기의 물 메니스커스는 AFM을 사용하여 측정하는 이미지에 영향을 주는 것으로 알려져 있다. 본 연구에서는 격자 기체 기반의 몬테카를로 시뮬레이션을 이용하여 탐침의 곡률과 결합 에너지 특성이 메니스커스의 형상과 그로 인해 발생하는 모세관 힘에 어떠한 영향을 미치는지 알아보았다. 일반적으로 탐침의 곡률이 커질수록, 친수성이 작아질수록 메니스커스 폭은 좁아지고 모세관 힘이 줄어드는 것을 확인하였다.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.395-402
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• 2009

The atomic force microscopy(AFM) has been used, as a powerful tool, to investigate physical properties of supported-lipid layers. Prior to the advent of the AFM, no observation was performed for the physical phenomena at the nanometer-scale. This microscope provides nanometer-scale morphology by scanning surfaces with the cantilever and presents force curve by monitoring the behavior of the cantilever that approaches to surface and retracts from the surface. From the morphology, the structures of the supported lipid layer and the effect of other molecules on the structures have been investigated. From the force curve, the surface properties-electrostatic and mechanical properties-of the supported lipid layers have been studied. In this article, characterization of the structure and surface properties of the supported lipid layer is explained. Future perspectives and direction are also discussed.

• Journal of the Korean Vacuum Society
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• v.16 no.1
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• pp.52-57
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• 2007

The interaction force between biomolecules(DNA-DNA, antigen-antibody, ligand-receptor, protein-protein) defines not only biomolecular function, but also their mechanical properties and hence bio-sensor. Atomic force microscopy(AFM) is nowadays frequently applied to determine interaction forces between biological molecules and biomolecular force measurements, obtained for example using AFM can provide valuable molecular-level information on the interactions between biomolecules. A proper modification of an AFM tip and/or a substrate with biomolecules permits the direct measurement of intermolecular interactions, such as DNA-DNA, protein-protein, and ligand-receptor, etc. and a microcantilever-based sensor appeared as a promising approach for ultra sensitive detection of biomolecular interactions.

• The Science & Technology
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• no.2 s.441
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• pp.40-42
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• 2006

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.325-335
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• 2014

원자 힘 현미경 (Atomic Force Microscopy, AFM) 탐침과 표면 사이의 좁은 공간에서 형성되는 나노미터 크기의 메니스커스는 AFM으로 측정하는 표면 이미지에 영향을 주는 것으로 알려져 있다. 본 연구에서는 격자 기체 기반의 몬테카를로 방법을 이용하여 계의 상대습도 변화에 따른 시스템의 크기와 표면의 곡률이 메니스커스의 모양 및 이로 인해 발생하는 모세관 힘에 미치는 영향을 알아 보았다. 일반적으로 시스템의 크기가 작을수록, 표면의 곡률이 클수록 (표면이 거칠수록), 메니스커스 폭은 좁아지고 모세관 힘이 줄어드는 것을 확인 하였다.

• Journal of the Korean Vacuum Society
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• v.16 no.1
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• pp.33-39
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• 2007

Electrical and mechanical modifications of devices based on carbon nanotubes(CNTs) using an atomic force microscope(AFM) in the forms of cutting and reconnection of CNTs are demonstrated. In addition to the modifications, electrostatic force microscopy is used to visualize the cutting and reconnection of CNTs. In this way, AFM is shown to be a useful tool in local modifications and manipulations of CNT-based devices.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.637-640
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• 2005

In this paper, we investigate the characteristics of a piezoresistive AFM cantilever in the range of $0\~30{\mu}N$ by using nano force calibrator (NFC), which consists of a high precision balance with resolution of 1 nN and 1-D fine positioning stage. Brief modeling of the cantilever is presented and then, the calibration results are shown. Tests revealed a linear relationship between the probing force and sensor output (resistance change), and the force vs. deflection. From this relationship, the force constant of the cantilever was calculated to 3.45 N/m with a standard deviation of 0.01 N/m. It shows that there is a big difference between measured and nominal spring constant of 1 N/m provided by the manufacturer s specifications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.77-80
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• 2005

Local probe techniques such as scanning probe microscopy (SPM) or atomic force microscopy (AFM) extended our perception into ultra small world. Specially, the sense of touching was extended by AFM into the micro- and nanoworld and has provided complementary new insights of the microscopic world. In addition, touching objects is an essential step before trying to manipulate things. SPM as a touch sensor not only measure the mechanical properties but also detect different properties such as magnetic, electrical, ionic, thermal, chemical and biophysical properties in nanoscale and even less. Obtaining biophysical measurements, monitoring dynamics and processes together with high-resolution imaging of the biomolecules and cells with rather simpler sample preparation than any other techniques give great attractions to the scientists experimenting with biological samples. Among the many AFM capabilities we will specifically introduce the force plot which is used to measure tip-sample interactions and its application this time.

• Tribology and Lubricants
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• v.28 no.4
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• pp.173-177
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• 2012

We used contact resonance force microscopy (CRFM) technique to determine the quantitative elastic properties of multiple materials integrated on the sub micrometer scale. The CRFM approach measures the frequencies of an AFM cantilever's first two flexural resonances while in contact with a material. The plain strain modulus of an unknown or test material can be obtained by comparing the resonant spectrum of the test material to that of a reference material. In this study we examined the following bumping materials for flip chip by using copper electrode as a reference material: NiP, Solder (Sn-Au-Cu alloy) and under filled epoxy. Data were analyzed by conventional beam dynamics and contact dynamics. The results showed a good agreement (~15% difference) with corresponding values determined by nanoindentaion. These results provide insight into the use of CRFM methods to attain reliable and accurate measurements of elastic properties of materials on the nanoscale.