• Proceedings of the KWS Conference
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• 2004.05a
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• pp.321-323
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• 2004

전자 제품에 사용되는 부품 ㆍ소재의 신뢰성 품질 평가를 위해 정밀한 모터의 제어기술, 첨단신호처리 기술, 압전소자 기술의 발달로 미세변화 계측의 재현성, 고분해능, 표면과 내부의 이미지관찰, 또한 미소부위에서 재료의 누설탄성표면파의 음속측정이 가능한 초음파현미경에 대한 연구가 최근 들어 활발히 진행되고 있다. (중략)

• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.29-37
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• 2021

The effect of Ar/N₂ two-step plasma treatment on the quantitative interfacial adhesion energy of low temperature Cu-Cu bonding interface were systematically investigated. X-ray photoelectron spectroscopy analysis showed that Ar/N₂ 2-step plasma treatment has less copper oxide due to the formation of an effective Cu4N passivation layer. Quantitative measurements of interfacial adhesion energy of Cu-Cu bonding interface with Ar/N₂ 2-step plasma treatment were performed using a double cantilever beam (DCB) and 4-point bending (4-PB) test, where the measured values were 1.63±0.24 J/m² and 2.33±0.67 J/m², respectively. This can be explained by the increased interfacial adhesion energy according phase angle due to the effect of the higher interface roughness of 4-PB test than that of DCB test.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.188-194
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• 2016

We propose an acousto-optic technique for the nondestructive evaluation of adhesion properties of a Pt/Ti thin-film interface. Since there are some problems encountered when using prevailing techniques to nondestructively evaluate the interfacial properties of micro/nano-scale thin-films, we applied an interferometer that combined the acoustic and optical methods. This technique is based on the Michelson interferometer but the resultant surface of the thin film specimen makes interference instead of the mirror when the interface is excited from the acoustic transducer at the driving frequency. The thin film shows resonance-like behavior at a certain frequency range, resulting in a low-contrast fringe pattern. Therefore, we represented quantitatively the change in fringe pattern as a frequency spectrum and discovered the possibility that the interfacial adhesion properties of a thin film can be evaluated using the newly proposed technique.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.81-88
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• 2019

In this study, the effects of graphene oxide (GO) addition on electromigration (EM) lifetime of Sn-3.0Ag-0.5Cu Pb-free solder joint between a ball grid array (BGA) package and printed circuit board (PCB) were investigated. After as-bonded, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) was formed at the interface of package side finished with electroplated Ni/Au, while $Cu_6Sn_5$ IMC was formed at the interface of OSP-treated PCB side. Mean time to failure of solder joint without GO solder joint under $130^{\circ}C$ with a current density of $1.0{\times}10^3A/cm^2$ was 189.9 hrs and that with GO was 367.1 hrs. EM open failure was occurred at the interface of PCB side with smaller pad diameter than that of package side due to Cu consumption by electrons flow. Meanwhile, we observed that the added GO was distributed at the interface between $Cu_6Sn_5$ IMC and solder. Therefore, we assumed that EM reliability of solder joint with GO was superior to that of without GO by suppressing the Cu diffusion at current crowding regions.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.4
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• pp.393-400
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• 2012

In recent years, nano-structured thin film systems are often applied in industries such as MEMS/NEMS device, optical coating, semiconductor or like this. Thin films are used for many and varied purpose to provide resistance to abrasion, erosion, corrosion, or high temperature oxidation and also to provide special magnetic or dielectric properties. Quite a number of articles to evaluate the characterization of thin film structure such as film density, film grain size, film elastic properties, and film/substrate interface condition were reported. Among them, the evaluation of film adhesive to substrate has been of great interest. In this study, we fabricated the polymeric thin film system with different adhesive conditions to evaluate the adhesive condition of the thin film. The nano-structured thin film system was fabricated by spin coating method. And then V(z) curve technique was applied to evaluate adhesive condition of the interface by measuring the surface acoustic wave(SAW) velocity by scanning acoustic microscope(SAM). Furthermore, a nano-scratch technique was applied to the systems to obtain correlations between the velocity of the SAW propagating within the system including the interface and the shear adhesive force. The results show a good correlation between the SAW velocities measured by acoustic spectroscope and the critical load measured by the nano-scratch test. Consequently, V(z) curve method showed potentials for characterizing the adhesive conditions at the interface by acoustic microscope.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.2
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• pp.76-82
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• 2009

In this papers, Study on the Bonding property and Strength Evaluation in Bonding interface Joints of Dissimilar material using DOE. We found optimal condition that uses experimental design method (Response Surface Analysis, DOE) used temperature, pressure, time on experiment factor. And we could get bonding condition and strength that break and crack do not happen in mechanical processing about united dissimilar material. And progress 3 point bending tests and verified result.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.233-233
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• 2003

교환바이어스(exchange bias)현상은 강자성과 반강자성의 접합계면에서 강한 상호 교환결합력에 의해 발생하는 것으로 알려져 있다. 이 현상은 1956년 Meiklejohn과 Bean에 의해 CoO 층으로 둘러싸인 Co 입자에서 발견된 이후, 강자성과 반강자성의 접합계면을 가지는 다층 박막에서의 교환바이어스에 대한 연구가 진행되어왔다. 이는 강자성/반강자성 박막의 교환바이어스 특성을 이용하여, 강자성 박막의 스핀방향을 고정시킬 수 있기 때문이다. 이러한 교환바이어스 특성은 하드드라이브의 고밀도 자기헤드소자 및 비휘발성 자기메모리소자에 응용되어지는 등 경제적 가치를 갖는 기술적인 면과 교환바이어스라는 자기특성의 학문적인 가치로 인해 이 분야에 대한 집중적인 투자와 연구가 이루어지고 있다 최근에는 교환바이 어스 현상의 원인과 형성기구에 대한 연구가 활발히 진행되고 있다. 그러나 강자성과 반강자성 박막의 단거리 상호 교환결합력에 의한 교환바이어스 현상은, 계면의 원자구조, 자기구조 및 각자성층의 여러 가지 인자들에 대해서 지속적으로 연구되고 있다. 본 연구에서는 Helmhertz 코일의 진동샘플형 자력계(VSM)을 이용하여 Si 기판위에 증착된 NiFe(10nm)/FeMn(t)/NiFe(10nm) 다층박막에서 FeMn층의 두께에 대한 각각의 교환바이어스 현상을 조사하고 사잇층 FeMn층의 surface를 Ar ion beam etching하여 etching 조건에 따른 교환바이어스를 비교분석 하고자 한다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.05a
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• pp.34.1-34.1
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• 2007

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.25-30
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• 1997

각각의 구조용 재료가 가지는 특성을 상호 보완하기 위하여 이종재료를 접합하여 응용할 수 있는 새로운 개념의 재료가 하이브리드 복합재료이다. 이종재료가 접한된 하이브리드 복합재료의 기계적 특성은 하이브리드 복합재료가 가지고있는 접합구조에 크게 의존되어 이에 따른 실험의 결과는 매우 다양하게 보고되고 있으며, 접합구조를 가지는 재료에 대한 연구의 관심은 탄성계수가 상이한 재료의 접합 면에 대한 계면에서의 이론적 해석분야에 있다. (중략)

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.265-272
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• 2003

This paper describes anodic bonding characteristics of MLCA (Multi Layer Ceramic Actuator) to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with same properties were deposited on MLCA under optimum RF magneto conditions(Ar 100%, input power $1\;W/cm^2$). After annealing in $450^{\circ}C$ for 1 hr, the anodic bonding of MLCA and Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in - 760 mmHg. Then, the MLCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity is 0.05-0.08 %FS. Moreover, any damages or separation of MLCA/Si bonded interfaces do not occur during actuation test. Therefore, it is expected that anodic bonding technology of MLCA/Si wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.