• 한국초전도ㆍ저온공학회논문지
• /
• 제14권4호
• /
• pp.28-31
• /
• 2012

We report the solid-liquid phase equilibria on the $GdBa_2Cu_3O_{7-{\delta}}$ (GdBCO) stability phase diagram in low oxygen pressures ($PO_2$) ranging from 1 to 100 mTorr. On the basis of the GdBCO stability phase diagram experimentally determined in low oxygen pressures, the isothermal sections of three different phase fields on log $PO_2$ vs. 1/T diagram were schematically constructed within the $Gd_2O_3-Ba_2CuO_y-Cu_2O$ ternary system, and the solid-liquid phase equilibria in each phase field were described. The invariant points on the phase boundaries include the following three reactions; a pseudobinary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3$ + liquid ($L_1$), a ternary peritectic reaction of $GdBCO{\leftrightarrow}Gd_2O_3+GdBa_6Cu_3O_y$ + liquid ($L_2$), and a monotectic reaction of $L_1{\leftrightarrow}GdBa_6Cu_3O_y+L_2$. A conspicuous feature of the solid-liquid phase equilibria in low $PO_2$ regime (1 - 100 mTorr) is that the GdBCO phase is decomposed into $Gd_2O_3+L_1$ or $Gd_2O_3+GdBa_6Cu_3O_y+L_2$ rather than $Gd_2BaCuO_5+L$ well-known in high $PO_2$ like air.

• Transactions on Electrical and Electronic Materials
• /
• 제5권3호
• /
• pp.109-112
• /
• 2004

In this study, in order to develop the low temperature sintering ceramics for ultrasonic vibrator, Pb(Sb$\_$$\frac{1}{2}$/Nb$\_$$\frac{1}{2}$/) O$_3$-Pb(Ni$\_$1/3/Nb$\_$2/3/)O$_3$-Pb(Zr$\_$0.48/Ti$\_$0.52/)O$_3$ ceramics were manufactured as a function of the amount of CuO addition, and their dielectric and piezoelectric characteristics were investigated. With increasing CuO addition, the grain size and density increased up to 0.3 wt% CuO addition. Taking into consideration electromechanical coupling factor(k$\_$p/) of 0.53, mechanical quality factor(Q$\_$m/) of 423, dielectric constant($\varepsilon$$\_$r/) of 1,759 and piezoelectric constant(d$\_$33/) of 362pC/N, it could be concluded that 0.5 wt% CuO added composition ceramic sintered at 920$^{\circ}C$ was suitable for ultrasonic vibrator application.

• 한국재료학회지
• /
• 제11권1호
• /
• pp.20-26
• /
• 2001

(hfac)Cu(1, 5-DMCOD)(1, 1, 1, 5, 5, 5-Hexafluoro-2, 4-pentanedionato Cu(I) 1, 5-dimethyl-cyclooctadine) 전구체와 He 운반기체를 이용하여 MOCVD(Metal Organic Chemical Vapor Deposition) 방법으로 Cu 박막을 형성하였으며, He 운반기체와 함께 $H_2$ gas 및 H(hfac) Ligand의 첨가가 Cu 박막 형성에 미치는 영향에 대하여 조사하였다. He운반기체만을 사용한 경우, Cu 박막의 증착율은 기판온도 180~$230^{\circ}C$에서 20~$125{\AA}/min$ 정도로 낮은 값을 보였으며, 특히 기판온도 $190^{\circ}C$에서는 매우 얇은 두께 ($700{\AA}$)이면서 낮은 비저항($2.8{\mu}{\Omega}cm$)을 갖는 Cu 박막이 형성됨을 알 수 있었다 He 운반기체와 함께 환원가스(H$_2$) 및 화학첨가제 (H (hfac) ligand)의 첨가 실험에서는 낮은 기판온도 ($180~190^{\circ}C$) 구간에서 현저하게 증착율이 증가하였으며 얇은 두께 (~$500{\AA}$)의 Cu 박막이 낮은 비저항(3.6~$2.86{\mu}{\Omega}cm$)을 갖는 것으로 나타났다. 또한 얇은 두께의 MOCVD Cu박막들의 표면 반사도(reflectance)는 $300^{\circ}C$에서 열처리한 sputter Cu의 반사도에 근접하는 우수한 surface morphology를 보였다 결국, (hfac)Cu(1,6-DMCOD) 전구체를 이용하여 얻어진 MOCVD Cu박막은 얇은 두께에서 낮은 비저항을 갖는 우수한 막질을 보였으며, Electrochemical deposition공정에서 conformal seed layer로써의 적용이 가능할 것으로 기대된다.

• 한국재료학회지
• /
• 제2권4호
• /
• pp.263-269
• /
• 1992

본 실험에서는 낮은 음의 온도계수를 갖는 저온 소결 유전체에 대해 연구하였다. 새로 개발된 재료의 조성은 Ti$O_2$(100-X) CuOx(X=1~5wt%)에 미량의 Mn$O_2$를 첨가 하였다. CuO를 첨가하지 않은 경우에는 저온 (90$0^{\circ}C$) 에서 소결이 진행되지 않았다. CuO 함량이 증가할수록 저온에서 소결이 가능하였으나, 유전율이 낮아지고 유전손실은 증가 하였다. Mn$O_2$를 0.6wt% 첨가한 경우 유전율과 Q값이 가장 높게 나타났다.

• 열처리공학회지
• /
• 제8권4호
• /
• pp.245-254
• /
• 1995

The purpose of this study was to examine the effects of low melting point phase(LMPP) on mechanical properties in the Al-Cu-Li-X(In, Be) alloys. This study was performed by the differential scanning calorimetry(DSC), the transmission electron microscope(TEM), hardness test, tensile test and notch tensile test. The shape of LMPP in the specimens homogenized at $570^{\circ}C$ was film type due to remelting at grain boundary during homogenization. Low melting point phases had no effects on mechanical properties in the aging treated materials, because the density of LMPPs was low. Mechanical properties of the aging treated materials were affected by the density of matrix precipitation phases and grain sizes. For the In or In, Be added Al-Cu-Li alloys, the optimum solution treatment temperature was $550^{\circ}C$. The strength of Al-Cu-Li-In-Be $T_6$ treated alloy was higher than that of 2090-$T_8$ alloy.

• 한국진공학회지
• /
• 제15권1호
• /
• pp.45-49
• /
• 2006

깨끗한 Cu(110)와 산소가 흡착된 Cu(110) 표면에 Cu 성장에 의한 광학적 이방성의 변화를 RDS를 이용하여 연구하였다. 250K에서 Cu를 성장하면서 성장 모드와 산소의 계면활성제 효과를 확인하였다. 두 표면에 Cu를 성장하면서 4,25eV 봉우리의 규칙적인 변화를 확인하여 layer-by-layer 모드를 확인하였다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
• /
• pp.6-8
• /
• 2004

The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1 % $O_2$＋99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ from 1, 06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCu $O_2$and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted N $d_{1＋x}$B $a_{2－x}$C $u_3$ $O_{y}$prepared under low oxygen partial pressure was distinctively improved.d.d.d.

• 마이크로전자및패키징학회지
• /
• 제21권4호
• /
• pp.63-68
• /
• 2014

For a nanoscale Cu/low-k wafer, inter-layer dielectric (ILD) and metal layers peelings, cracks, chipping, and delamination are the most common dicing defects by traditional diamond blade saw process. Sidewall void in sawing street is one of the key factors to bring about cracks and chipping. The aim of this research is to evaluate laser grooving & mechanical sawing parameters to eliminate sidewall void and avoid top-side chipping as well as peeling. An ultra-fast pico-second (ps) laser is applied to groove/singulate the 28-nanometer node wafer with Cu/low-k dielectric. A series of comprehensive parametric study on the recipes of input laser power, repetition rate, grooving speed, defocus amount and street index has been conducted to improve the quality of dicing process. The effects of the laser kerf geometry, grooving edge quality and defects are evaluated by using scanning electron microscopy (SEM) and focused ion beam (FIB). Experimental results have shown that the laser grooving technique is capable to improve the quality and yield issues on Cu/low-k wafer dicing process.

• Journal of Radiation Protection and Research
• /
• 제42권1호
• /
• pp.63-68
• /
• 2017

Background: The combined effect of the low energy electron (LEE) irradiation and $Cu^{2+}$ ion on DNA damage was investigated. Materials and Methods: Lyophilized pBR322 plasmid DNA films with various concentrations (1-15 mM) of $Cu^{2+}$ ion were independently irradiated by monochromatic LEEs with 5 eV. The types of DNA damage, single strand break (SSB) and double strand break (DSB), were separated and quantified by gel electrophoresis. Results and Discussion: Without electron irradiation, DNA damage was slightly increased with increasing Cu ion concentration via Fenton reaction. LEE-induced DNA damage, with no Cu ion, was only 6.6% via dissociative electron attachment (DEA) process. However, DNA damage was significantly increased through the combined effect of LEE-irradiation and Cu ion, except around 9 mM Cu ion. The possible pathways of DNA damage for each of these different cases were suggested. Conclusion: The combined effect of LEE-irradiation and Cu ion is likely to cause increasing dissociation after elevated transient negative ion state, resulting in the enhanced DNA damage. For the decrease of DNA damage at around 9-mM Cu ion, it is assumed to be related to the structural stabilization due to DNA inter- and intra-crosslinks via Cu ion.

• 한국재료학회지
• /
• 제23권9호
• /
• pp.525-530
• /
• 2013

This study investigated the continuous cooling transformation, microstructure, and mechanical properties of highstrength low-alloy steels containing B and Cu. Continuous cooling transformation diagrams under non-deformed and deformed conditions were constructed by means of dilatometry, metallographic methods, and hardness data. Based on the continuous cooling transformation behaviors, six kinds of steel specimens with different B and Cu contents were fabricated by a thermomechanical control process comprising controlled rolling and accelerated cooling. Then, tensile and Charpy impact tests were conducted to examine the correlation of the microstructure with mechanical properties. Deformation in the austenite region promoted the formation of quasi-polygonal ferrite and granular bainite with a significant increase in transformation start temperatures. The mechanical test results indicate that the B-added steel specimens had higher strength and lower upper-shelf energy than the B-free steel specimens without deterioration in low-temperature toughness because their microstructures were mostly composed of lower bainite and lath martensite with a small amount of degenerate upper bainite. On the other hand, the increase of Cu content from 0.5 wt.% to 1.5 wt.% noticeably increased yield and tensile strengths by 100 MPa without loss of ductility, which may be attributed to the enhanced solid solution hardening and precipitation hardening resulting from veryfine Cu precipitates formed during accelerated cooling.