헵틸알콜 기반의 Cu계 나노입자 합성에서 온도 및 올레일아민 첨가량의 효과

지상수,이종현,Chee, Sang-Soo,Lee, Jong-Hyun 한국마이크로전자및패키징학회 2014 마이크로전자 및 패키징학회지 Vol.21 No.3

헵틸알콜 기반의 화학적 합성법으로 나노급 Cu 입자의 제조를 실시해 보았으며, 합성 공정의 주요 공정변수인 합성 온도 및 올레일아민의 첨가량에 따른 생성 나노입자의 종류 및 형상 변화에 대해 논의하였다. 합성 온도 및 올레 일아민 첨가량에 따라 생성 나노 입자의 종류 및 형상은 크게 변화하였다. $160^{\circ}C$의 합성 온도 조건에서는 불완전한 환원반응의 영향으로 올레일아민 첨가량에 관계없이 육면체 형태의 $Cu_2O$ 상만이 합성되었고, 올레일아민 첨가량이 증가할수록 $Cu_2O$ 입자들의 평균 크기는 감소하였다. 그러나 $170^{\circ}C$의 온도에서 합성을 실시한 경우에서는 불규칙한 구형 및 땅콩형 나노 입자들이 관찰되었다. 또한 올레일아민 첨가량이 증가할수록 입자들의 평균 크기는 지속적으로 서서히 감소하는 경향을 나타내었으며, 이때 생성 물질도 $Cu_2O$인 경우서부터 순수 Cu 상태로 변화되면서 합성되는 결과가 관찰되었다. With synthesis temperature and adding amount of oleylamine, nanometer-sized Cu particles were fabricated by heptyl alcohol-based chemical synthesis. The synthetic temperature and amount of oleylamine changed excessively the shape and phase of synthesized nanoparticles. Only cubic-shaped $Cu_2O$ phase was formed at $160^{\circ}C$ regardless of the amount of oleylamine because of imperfect reduction reaction, representing results that the average size of $Cu_2O$ particles decreased with increasing the amount of oleylamine. In the case the synthesis at $170^{\circ}C$, however, nanoparticles of irregular sphere or peanut shapes were synthesized. Moreover, the average size of nanoparticles decreased continuously and gradually with an increase of the amount of oleylamine. According to the size decrease, the synthesized $Cu_2O$ nanoparticles were also transformed into pure Cu nanoparticles.

Fabrication of Cu-Ni Mixed Phase Layer Using DC Electroplating and Suppression of Kirkendall Voids in Sn-Ag-Cu Solder Joints

지상수,이종현 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.3

A solderable layer concurrently containing Cu-rich and Ni-rich phases (mixed-phase layer, MPL) was fabricated by direct current electroplating under varying process conditions. Current density was considered as the main parameter to adjust the microstructure and composition of MPL during the electroplating process, and deposit thickness were evaluated as functions of plating time. As a result, it was observed that the coral-like structure that consisted of Cu-rich and Ni-rich phases grew in the thickness direction. The most desirable microstructure was obtained at a relatively low current density of 0.4 mA/cm2. In other words, the surface was the smoothest and defect-free at this current density. The electroplating rate was slightly enhanced with an increase in current density. Investigations of its solid-state reaction properties, including the formation of Kirkendall voids, were also carried out after reflow soldering with Sn-3.0 Ag-0.5 Cu solder balls. In the solid-state aging experiment at 125°C, Kirkendall voids at the normal Sn-3.0 Ag-0.5 Cu solder/Cu interface were easily formed after just 240 h. Meanwhile, the presence of an intermetallic compound (IMC) layer created in the solder/MPL interface indicated a slightly lower growth rate, and no Kirkendall voids were observed in the IMC layer even after 720 h.

화학적 습식 합성법에서 친환경 슈거 환원제 및 젤라틴 캡핑제에 의한 주석계 나노입자의 제조

지상수,윤영은,유은선,박상현,박성영,이석희,박인선,이종현,Chee, Sang-Soo,Yun, Young-En,You, Eun-Sun,Park, Sang-Hyun,Park, Sung-Young,Lee, Seok-Hee,Park, In-Seon,Lee, Jong-Hyun 한국마이크로전자및패키징학회 2012 마이크로전자 및 패키징학회지 Vol.19 No.4

Tin(II) acetate 전구체를 사용한 습식 환원 합성법으로 나노입자를 제조하는 공정에서 친환경 환원제(슈거) 및 캡핑제(젤라틴)를 사용하여 합성 조건 및 합성 시간에 따른 주석 나노입자의 합성 특성을 분석하였다. 글루코스 환원제를 사용하여 $70-110^{\circ}C$의 온도에서 합성 시 불규칙한 사슬 형태로 군집체를 이루면서 배열된 환원 나노입자들이 관찰되었다. FFT 패턴 분석으로부터 이러한 나노입자들은 $SnO_2$ 상으로 분석되었다. 수크로오스 환원제로 사용하여 $110^{\circ}C$에서 합성을 실시한 경우에서는 3시간의 합성 시간에서 평균 약 10 nm급의 미세한 구형 나노입자들을 형성시킬 수 있었으나, 합성 시간을 9시간으로 증가시킨 경우에서는 불규칙하게 뭉친 나노입자들 외에도 사슬 형태의 나노입자 군집체들이 국부적으로 형성되는 거동이 관찰되었다. 그러나 $130^{\circ}C$ 합성 시에는 사슬 형태의 나노입자 군집체들만을 관찰할 수 있었다. 그 결과 구형의 나노입자는 순수 Sn 상으로, 사슬 형태 나노입자 군집체들은 $SnO_2$ 상으로 각각 분석되었다. In the synthesis of nanoparticles (NPs) via wet chemical reduction using tin(II) acetate precursor, the effects of green reducing agents (sugar) and a capping agent (gelatin) on the formation of NPs were analyzed as functions of synthesis conditions and time. When glucose was used as the reducing agent, it was observed that irregular chainlike shapes, aggregates of NPs, were formed during the synthesis at $70-110^{\circ}C$. The NPs were determined as $SnO_2$ from the fast Fourier transform (FFT) pattern. In the synthesis at $110^{\circ}C$ by using sucrose, fine spherical NPs of ~10 nm in diameter were formed after the synthesis time of 3 h. As the time increased to 9 h, the chainlike NP aggregates besides irregularly aggregated spherical NPs were also formed locally. However, the chainlike NP aggregates were only observed when the synthesis was conducted at $130^{\circ}C$. The spherical NPs and chainlike NP aggregates were analyzed to be pure Sn and $SnO_2$, respectively.

2차원 전이금속칼코겐 화합물 소재의 결함 제어 연구 동향

지상수,함문호 한국세라믹학회 2017 세라미스트 Vol.20 No.3

화학적 합성법을 이용한 마이크론 이하급 2SnO·(H₂O) 분말의 합성과 하소 특성

지상수,이종현,Chee, Sang-Soo,Lee, Jong-Hyun 한국재료학회 2013 한국재료학회지 Vol.23 No.11

Synthesis of sub-micron $2SnO{\cdot}(H_2O)$ powders by chemical reduction process was performed at room temperature as function of viscosity of methanol solution and molecular weight of PVP (polyvinylpyrrolidone). Tin(II) 2-ethylhexanoate and sodium borohydride were used as the tin precursor and the reducing agent, respectively. Simultaneous calcination and sintering processes were additionally performed by heating the $2SnO{\cdot}(H_2O)$ powders. In the synthesis of the $2SnO{\cdot}(H_2O)$ powders, it was possible to control the powder size using different combinations of the methanol solution viscosity and the PVP molecular weight. The molecular weight of PVP particularly influenced the size of the synthesized $2SnO{\cdot}(H_2O)$ powders. A holding time of 1 hr in air at $500^{\circ}C$ sufficiently transformed the $2SnO{\cdot}(H_2O)$ into $SnO_2$ phase; however, most of the PVP (molecular weight: 1,300,000) surface-capped powders decomposed and was removed after heating for 1 h at $700^{\circ}C$. Hence, heating for 1 h at $500^{\circ}C$ made a porous $SnO_2$ film containing residual PVP, whereas dense $SnO_2$ films with no significant amount of PVP formed after heating for 1 h at $700^{\circ}C$.

변형 폴리올 공정에서 Sn 나노입자의 합성 특성에 미치는 용매의 종류 및 점도의 영향

지상수 ( Sang Soo Chee ),김지환 ( Ji Hwan Kim ),이종현 ( Jong Hyun Lee ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.4

We report on the effect of solvent type on the synthesis of Sn nanoparticles via a modified polyol method at room temperature in an ambient atmosphere. In the synthesis, tin (II) 2-ethylhexanoate, sodium borohydride (NaBH4), and polyvinylpyrrolidone (PVP) were used as a precursor, reducing agent, and capping molecule, respectively. Transmission electron microscopy confirmed by that the Sn nanoparticles obtained in 1,5-pentanediol were smaller (9.2 nm) than 10 nm for an average diameter and had a narrow size distribution. We also observed that the average diameter of Sn nanoparticles obtained in 1,5-pentanediol increased slightly with a decreasing PVP molecular weight. The result can explain the synthesis mechanism in which Sn ions are not only preferential in forming a complex with the PVP but also preferentially reduced in a solvent, and the movement of reduced particles is influenced by the PVP. Consequently, an increase in PVP molecular weight may more effectively inhibit coalescence between nanoparticles, which are surrounded by a longer molecular chain and are highly viscous in the synthesis solution, all of which finally results in a decrease in the average particle size. On the basis of Fourier-transform infrared spectroscopy result, we demonstrated that the PVP on the Sn surface could be removed using an acetone/methanol mixed solvent. (Received January 20, 2014)

용액공정을 이용하여 제조된 Li-doped ZnO/CNT 복합체 기반 고성능 박막 트랜지스터

지상수(S.S. Chee),손기철(G.C. Son),전지현(J.H. Jun),손명우(M.W. Son),함문호(M.H. Ham) 한국생산제조학회 2015 한국생산제조시스템학회 학술발표대회 논문집 Vol.2015 No.10

알루미나에 코팅된 생체활성유리의 결정화에 따른 수산화 아파타이트 형성

이은성,지상수,김철영 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.3

생체활성 유리를 알루미나 기판에 코팅하고 이를 유사 생체 용액에 반응시켰을 때 코팅 유리층 표면에 생성된 수산화 아파타이트 형성 거동 변화에 대하여 연구하였다. 알루미나에 코팅된 생체 활성 유리를 여러 온도에서 열처리하였을 때 다양한 종류의 결정상이 나타났으며, 특히 110$0^{\circ}C$에서 열처리하였을 때는 $\beta$-wollastonite와 apatite, 120$0^{\circ}C$에서 열처리하였을 때는 $\alpha$-wollastonite와 apatite가 생성되었다. 이들 시편을 tris-완충용액에 반응시켰을 때, $\alpha$-wollastonite 결정의 부식 속도가 $\beta$-wollastonite의 부식 속도보다 빨랐다. 그리고 이들 시편을 유사 생체 용액과 반응시켰을 때는 두 코팅층 표면에서 수산화 아파타이트가 형성되었는데, 그 형성 속도는 $\alpha$-wollastonite가 포함된 시편에서 더 빨랐다. Alumina glazed with a bioactive glass reacted in Simulated Body Fluids(SBF) to investigate the behavior of hydroxyapatite formation on the glass coat layer. Various crystalline phases were found depending on the firing temperatures when the bioactive glass coat was heat-treated. The glass coat was crystallized into ${\beta}$-wollastonite and apatite when fired at 1100$^{\circ}C$, and ${\alpha}$-wollastonite and apatite when fired at 1200$^{\circ}C$. Those samples reacted in SBF, and it is observed that hydroxyapatite developed on the surface of the crystallized glaze. Its formation was much easier in the sample with ${\alpha}$-wollastonite than with ${\beta}$-wollastonite. This is because that the ${\alpha}$-wollastonite dissolves more easily than ${\beta}$-wollastonite does in SBF.

습식 환원법에 의한 Cu 나노입자의 합성 동향

신용무,지상수,이종현,Shin, Yong Moo,Chee, Sang-Soo,Lee, Jong-Hyun 한국마이크로전자및패키징학회 2013 마이크로전자 및 패키징학회지 Vol.20 No.3

Interest in copper nanoparticles has increased as an alternative for substituting silver nanoparticles because of its lower cost and less electromigration effect than silver. In this paper, the recent research trends and main results in wet-chemical synthesis of sub-100 nm Cu nanoparticles were summarized. The characteristics of synthesis were discussed with a classification such as modified polyol synthesis, modified hydrothermal synthesis, solvothermal synthesis, and the others, focussing on effects of capping agents, reductants, and pH. Information on the oxidation of synthesized copper nanoparticles were additionally commented.

Al2O3, ZrO2, TiO2 가 첨가된 유리에서의 수산화 아파타이트 형성

전유남,김철영,지상수 한국생체재료학회 2003 생체재료학회지 Vol.7 No.1

Oxides, such as Al2O3, ZrO2 and TiO2, were known as oxides which enhance the chemical properties when added in glass compositions. In this study, Al2O3, ZrO2 and TiO2 were added to a bioactive glass composition to examine the effect of those oxides on the formaion of hydroxyapatite on the glass surface. The bioactive glasses containing Al2O3, ZrO2 and TiO2 were reacted in simulated body fluid and tris-buffer solution to evaluate the change of the rate of hydroxyapatite formation. Al3+, Zr4+ and Ti4+ ions improved the chemical durability of the bioactive glass. However, the additions retarded the formation of silica-rich layer, which is essential for the hydroxyapatite formation. This is because the metal ions reduce the leaching of Ca2+ ions. The behavior of hydroxyapatite formation was also explained in terms of the leaching rate of Si4+ ion.