원자스케일 마찰의 하중 및 강성 의존성

성인하,Sung, In-Ha 한국트라이볼로지학회 2007 한국윤활학회지(윤활학회지) Vol.23 No.1

Despite numerous researches on atomic-scale friction have been carried out for understanding the origin of friction, lots of questions about sliding friction still remain. It is known that friction at atomic-scale always shows unique phenomena called 'stick-slips' which reflect atomic lattice of a scanned surface. In this work, experimental study on the effects of system stiffnesses and load on the atomic-scale stick-slip friction of graphite was performed by using an Atomic Force Microscope and various cantilevers/tips. The objective of this research is to figure out the dependency of atomic-scale friction on the nanomechanical properties in sliding contact such as load, stiffness and contact materials systematically. From this work, the experimental observation of transitions in atomic-scale friction from smooth sliding to multiple stick-slips in air was first made, according to the lateral cantilever stiffness and applied normal load. The superlubricity of graphite could be verified from friction vs. load experiments. Based on the results, the relationship between the stickslip behaviors and contact stiffness was carefully discussed in this work. The results or this work indicate that the atomic-scale stick-slip behaviors can be controlled by adjusting the system stiffnesses and contact materials.

On the Relationship between Material Removal and Interfacial Properties at Particulate Abrasive Machining Process

성인하,Sung, In-Ha Korean Tribology Society 2009 한국트라이볼로지학회지 (Tribol. Lubr.) Vol.18 No.3

본 연구에서는 마이크로/나노입자를 이용한 연마가공 공정에서의 입자-표면간 접촉상황에서 접촉계면의 기계적 성질과 재료제거율간의 관계를 실험적으로 고찰하였다. 연마가공 공정에서의 입자-평면간 접촉을 모사하기 위하여 팁 대신 실리카 입자를 부착한 콜로이드 프로브를 이용한 원자현미경 실험을 통하여 마찰력과 강성을 실험적으로 측정하였다. 실험결과와 이론적 접촉해석으로부터, 마찰계수는 횡방향 접촉강성에 따라 대체적으로 증가하고 재료제거율은 실리카 입자와 Cu, PolySi, Ni과 같은 다양한 재료표면간 접촉에서의 마찰계수들과 지수함수적인 비례관계를 가지고 있음을 규명하였다. In this paper, the relationship between the material removal rate and the interfacial mechanical properties at particle-surface contact situation, which can be seen in an abrasive machining process using micro/nano-sized particles, was discussed. Friction and stiffnesses were measured experimentally on an atomic force microscope (AFM) by using colloidal probes which have a silica colloid particle in place of tip to simulate a particle-flat surface contact in an abrasive machining process. From the experimental investigation and theoretical contact analysis, the interfacial contact properties such as lateral stiffness of contact, friction, the material removal rate were presented with respect to some of material surfaces and the relationship between the properties as well.

나노프로브 응용 기계-화학적 나노리소그래피 기술

성인하(In-Ha Sung),김대은(Dae-Eun Kim),신보성(Bo-Sung Shin) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4

With the advancement of micro-systems and nanotechnology, the need for ultra-precision fabrication<br/> techniques has been steadily increasing. In this paper, a novel nano-structure fabrication process that is<br/> based on the fundamental understanding of nano-scale tribological interaction is introduced. The process,<br/> which is called Mechano-Chemical Scanning Probe Lithography (MC-SPL), has two steps, namely,<br/> mechanical scribing for the removal of a resist layer and selective chemical etching on the scribed regions.<br/> Organic monolayers are used as a resist material, since it is essential for the resist to be as thin as possible in<br/> order to fabricate more precise patterns and surface structures. The results show that high resolution patterns<br/> with sub-micrometer scale width can be fabricated on both silicon and various metal surfaces by using this<br/> technique.

On the Relationship between Material Removal and Interfacial Properties at Particulate Abrasive Machining Process

성인하(In-Ha Sung) 한국트라이볼로지학회 2009 한국윤활학회지(윤활학회지) Vol.25 No.6

본 연구에서는 마이크로/나노입자를 이용한 연마가공 공정에서의 입자-표면간 접촉상황에서 접촉계면의 기계적 성질과 재료제거율간의 관계를 실험적으로 고찰하였다. 연마가공 공정에서의 입자-평면간 접촉을 모사하기 위하여 팁 대신 실리카 입자를 부착한 콜로이드 프로브를 이용한 원자현미경 실험을 통하여 마찰력과 강성을 실험적으로 측정하였다. 실험결과와 이론적 접촉해석으로부터, 마찰계수는 횡방향 접촉강성에 따라 대체적으로 증가하고 재료제거율은 실리카 입자와 Cu, PolySi, Ni과 같은 다양한 재료표면간 접촉에서의 마찰계수들과 지수함수적인 비례관계를 가지고 있음을 규명하였다. In this paper, the relationship between the material removal rate and the interfacial mechanical properties at particle-surface contact situation, which can be seen in an abrasive machining process using micro/nano-sized particles, was discussed. Friction and stiffnesses were measured experimentally on an atomic force microscope (AFM) by using colloidal probes which have a silica colloid particle in place of tip to simulate a particle-flat surface contact in an abrasive machining process. From the experimental investigation and theoretical contact analysis, the interfacial contact properties such as lateral stiffness of contact, friction, the material removal rate were presented with respect to some of material surfaces and the relationship between the properties as well.

다양한 AFM 캔틸레버/팁을 이용한 원자스케일 마찰 연구

성인하(In-Ha Sung),Robert W. Carpick 한국트라이볼로지학회 2006 한국트라이볼로지학회 학술대회 Vol.2006 No.6

In order to obtain a fundamental understanding of the origin of atomic-scale stick-slip friction, the experimental investigation of atomic-scale stick-slip frictional behaviors between nano-to micro-scale tips and a highly oriented pyrolitic graphite (HOPG) surface were performed using atomic force microscope (AFM) cantilevers with different stiffnesses and tips. The primary objective of this research is to determine how atomic-scale stick-slip depends on the mechanical and material properties of the system. Experimental results showed that the stick-slip frictional behaviors could occur even when the colloidal probes with a particle of about 10 urn in diameter, which thus have a relatively large contact area and lack a well-shaped tip end, were used. This indicates that atomic stick-slip friction may be a more common phenomenon than currently thought. Also, unlike the well-known normal stick-slip behavior that shows single stick/slip per a unit cell of a graphite surface structure, we first observed transitions in the stick-slip behavior from smooth sliding to multiple sticks/slips (jumps) according the lateral lever stiffness and contact stiffness of system. Based on the experimental results, the relationship between the range of stick-slip behaviors observed, contact stiffness, tip material, and cantilever type was carefully investigated in this work.

미세입자의 트라이볼로지적 응용을 위한 마찰특성 고찰

성인하(In-Ha Sung),한흥구(Hung-gu Han),공호성(Hosung Kong) 한국트라이볼로지학회 2009 한국윤활학회지(윤활학회지) Vol.25 No.2

Interests in micro/nano-particles have been greatly increasing due to their wide applications in various fields such as environmental and medical sciences as well as engineering. In order to obtain a fundamental understanding of the tribological characteristics at particle-surface contact interface, frictional behaviors according to load/pressure and materials were obtained by using atomic force microscope (AFM) cantilevers with different stiffnesses and tips. Lateral contact stiffnesses were observed in various tip-surface contact situations. Experimental results show that stick-slip friction behavior occurs even when the colloidal probes with a particle of a few micrometers in diameter, which have a relatively large contact area and lack a well-shaped apex, were used. This indicates that atomic stick-slip friction may be a more common phenomenon than it is currently thought to be. Also, experimental results were investigated by considering the competition between the stiffness of the interatomic potential across the interface and the elastic stiffnesses of the contacting materials and the force sensor itself.

입자 연마 가공에서의 연마 입자-공작물 표면간 접촉에 따른 마찰해석

성인하(In-Ha Sung),한흥구(Hung-Gu Han),공호성(Hosung Kong) 한국트라이볼로지학회 2009 한국트라이볼로지학회 학술대회 Vol.2009 No.11

In this paper, the relationship between the material removal rate and the interfacial mechanical properties at particle-surface contact situation, which can be seen in an abrasive machining process using micro/nano-sized particles, was discussed. Friction and stiffnesses were measured experimentally on an atomic force microscope (AFM) by using colloidal probes which have a silica colloid particle in place of tip to simulate a particle-flat surface contact in an abrasive machining process. From the experimental investigation and theoretical contact analysis, the interfacial contact properties such as lateral stiffness of contact, friction, the material removal rate were presented with respect to some of material surfaces and the relationship between the properties as well.

자기 조립 분자막의 표면파손특성 및 미세 금속 구조물 제작에의 응용

성인하(In-Ha Sung),김대은(Dae-Eun Kim) 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.35 No.-

The motivation of this work is to use SAM(Self-Assembled Monolayer) for developing a rapid and flexible non-photolithographic nano-structure fabrication technique which can be utilized in micro-machining of metals as well as silicon-based materials. The fabrication technique implemented in this work consists of a two-step process, namely, mechanical scribing followed by chemical etching. From the experimental results, it was found that thiol on copper surface could be removed even under a few nN normal load. The nano-tribological characteristics of thiol-SAM on various metals were largely dependent on the native oxide layer of metals Based on these findings, nano-patterns with sub-micrometer width and depth on metal surfaces such as Cu, Au and Ag could be obtained using a diamond-coated tip.

반도체 CMP공정에서의 웨이퍼 표면결함 생성 메커니즘에 대한 연구

성인하(In-Ha Sung),양우열(Woo Yul Yang),곽하슬로미(Hasromi Kwark) 한국트라이볼로지학회 2012 한국트라이볼로지학회 학술대회 Vol.2012 No.4

기계화학적 연마공정중 패드내 미세공극에서의 연마입자의 거동

곽하슬로미(Haslomi Kwark),양우열(Woo-Yul Yang),성인하(In-Ha Sung) 한국트라이볼로지학회 2012 한국윤활학회지(윤활학회지) Vol.28 No.1

In this paper, the results of finite element(FE) analysis of chemical mechanical polishing(CMP) process using 2-dimensional elements were discussed. The objective of this study is to find the generation mechanism of microscratches on a wafer surface during the process. Especially, a FE model with a panicle inside pad pore was considered to observe how such a contact situation could contribute to microscratches generation. The results of the finite element simulations revealed that during CMP process the pad-particle mixture could be formed and this would be a major factor leading to microscratch generation.