• 한국전기전자재료학회논문지
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• 제36권4호
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• pp.418-421
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• 2023

Multilayer Ceramic Capacitors (MLCCs) are essential passive components in the electronics industry, known for their high capacitance due to the multilayer structure comprising inner electrodes and dielectric layers. Nickel electrodes are commonly used in MLCCs as the inner electrodes, and to prevent oxidation during the co-firing of the dielectric layers with nickel electrodes, reducing atmosphere is required. However, reducing atmosphere sintering can also induce a reduction of the dielectric, necessitating precise control of oxygen partial pressure. To explore the possibility of using oxide electrodes that do not require reducing atmosphere sintering, we analyze the electrical properties of nickel oxide (NiO) as a potential candidate. As a preliminary study on its use as an alternative inner electrode, the correlation between microstructure and electrical properties of bulk NiO under different sintering conditions was investigated to gain insights into the conduction mechanisms of the material.

• 한국재료학회지
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• 제5권2호
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• pp.151-156
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• 1995

$(Ba, Sr)TiO_{3}$계에 저융점의 Glass물질을 첨가하여 저온소결이 가능하며, 고유전율을 갖는 유전체 재료를 제조하여, 그 특성을 조사하였다. 본 연구에서는 고유전율의 $(Ba, Sr)TiO_{3}$계에 PbO함량이 서로 다른 Glass물질을 첨가하여 조성변화에 따른 저온소결거동 및 유전특성을 조사하였으며, 적층형 세라믹 Capacitor(MLCC)에 응용하기 위하여 다양한 조성으로 제조하였다. $PbO-ZnO-B_{2}O_{2}$계 Glass 성분을 첨가하여 소결온도를 $1350^{\circ}C$에서 $1050^{\circ}C$까지 낮출수 있었으며, 4wt% glass 첨가로 $1150^{\circ}C$ 이하에서 2시간 소결한 저온소결용 재료는 실온에서 8000정도의 높은 비유전율과 0.005의 낮은 유전손실 그리고 광역온도범위에서 유전상수의 안정성을 가진 우수한 특성을 나타내며, 입자크기가 1~3 $\mu$m 정도로 치밀한 미세구조를 가지고 있다. 본 연구의 저온소결용 유전체 재료는 Z5U 규격을 만족시키고 기존의 $BaTiO_{3}$계 재료에 비해 낮은 소결온도를 가지므로 MLCC에 응용시 내부전극으로 Ag-Pd alloy 사용이 가능한 것으로 밝혀졌다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.139-142
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• 2001

As microeletronics technology continues to progress, there is also a continuous demand on highly integration and miniaturization of systems. For example, it is desirable to package several integrated circuits together in multilayer structure, such as multichip modules, to achieve higher levels of compactness and higher performance. Passive components (i.e., capacitors, resistors, and inductors) are very important for many MCM applications. In addition, the low-temperature co-fired ceramic (LTCC) process has considerable potential for embedding passive components in a small area at a low cost. In this paper, we investigate a method of statistically modeling integrated passive devices from just a small number of test structures. A set of LTCC inductors is fabricated and their scattering parameters (5-parameters) are measured for a range of frequencies from 50MHz to 5GHz. An accurate model for each test structure is obtained by using a building block based modeling methodology and circuit parameter optimization using the HSPICE circuit simulator.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.124-125
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• 2006

Multilayer ceramic capacitor (MLCC) miniaturization has increased the demand for superfine $BaTiO_3$ powder due to its thin dielectric layer. Hydrothermally synthesized $BaTiO_3$ powder a pseudo-cubic phase resulting in poor dielectric properties due to size effect and hydroxyl ion inclusion in the $BaTiO_3$ lattice. We attempted a superfine (lower than 100 nm) highly tetragonal $BaTiO_3$ powder via a solvothermal method without precipitating agent. The lattice parameters and the relative amounts of tetragonal and cubic phases were determined using Rietveld refinement.

• 한국전기전자재료학회논문지
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• 제15권4호
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• pp.344-348
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• 2002

As microelectronics technology continues to progress, there is also a continuous demand on highly integration and miniaturization of systems. For example, it is desirable to package several integrated circuits together in multilayer structure, such as multichip modules, to achieve higher levels of compactness and higher performance. Passive components (i.e., capacitors, resistors, and inductors) are very important fort many MCM applications. In addition, the low-temperature co-fired ceramic (LTCC) process has considerable potential for embedding passive components in a small area at a low cost. In this paper, we investigate a method of statistically modeling integrated passive devices from just a small number of test structures. A set of LTCC inductors is fabricated and their scattering parameters (s-parameters) are measured for a range of frequencies from 50MHz to 5GHz. An accurate model for each test structure is obtained by using a building block based modeling methodology and circuit parameter optimization using the HSPICE circuit simulator.

• 한국세라믹학회지
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• 제46권2호
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• pp.175-180
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• 2009

Multilayer ceramic capacitors (MLCCs) have continually been made smaller in size and larger in capacity in resent years. However, the end termination electrode is still thick in many MLCCs. In this study, we used small grain glass frit to embody thin film and highly densification in the end termination by improve sintering driving force with well-dispersion and rising surface energy. Pastes were fabricated using size changed glass frit, such as 0.1 ${\mu}m$, 0.5 ${\mu}m$, 1.0 ${\mu}m$, 4.0 ${\mu}m$. Fabricated pastes were applied 05A475KQ5 chip and fired various sintering temperatures to analyze sintering behavior of pastes. Consequently, small glass frit used pastes have many merits than larger, such as well-dispersion, improve cornercoverage and surface roughness, possibility of low temperature sintering. However, we confirmed that small glass frit used pastes have narrow sintering window by rapid completion of sintering densification.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.747-749
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• 1992

In this study, $0.45Pb(Fe_{1/2}Nb_{1/2})O_3-(0.55-x)Pb(Fe_{2/3}W_{1/3})O_3-xPb(Mg_{1/3}Nb_{2/3})O_3(x=0.20, 0.25, 0.30)$ (x=0.20, 0.25, 0.30) ceramics were fabricated by the mixed oxide method. The sintering temperature and time were 950-990[$^{\circ}C$], 2[hr], respectively. The dielectric and structural properties with the composition and sintering temperature were investigated for the application as multilayer ceramic capacitors. To improve the dielectric loss, specimens doped with $MnO_2$, (0$\sim$2.0 [mol%] ) were fabricated and their dielectric properties were studied. With increasing the amount of $MnO_2$, dielectric constant was decreased and transition temperature was increased. Dielectric constant and dielectric loss of the 0.45PFN-0.30PFW-0.25PMN+$MnO_2$(1.0[mol.%]specimen(970[$^{\circ}C$]) had a good properties of 11,227, 1.3[%].

• 한국재료학회지
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• 제13권12호
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• pp.779-784
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• 2003

Nickel powders were obtained by various preparation methods, and their sintering characteristics were investigated. Nickel powders made by wet chemical process (WCP) had a higher surface area and more narrow size distribution than that of chemical vapor deposition (CVD) method. Nickel-oxide powders by the WCP method were prepared at $200^{\circ}C$ for 3 hr. The oxidation behaviour of nickel-oxide powder is similar with that of the CVD method. Nickel powders made by the WCP method showed a higher shrinkage in the range of $600^{\circ}C$∼$900^{\circ}C$ than that of commercial powder made by the CVD method. The similar results were observed on the surface microstructure of sintered bodies by SEM measurements.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.239-246
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• 2004

가속열화시험은 가속수명시험시에 고장 개수가 적거나 심지어 고장이 발생하지 않는 경우에도 부품의 신뢰성을 평가할 수 있는 유용한 수단이 되고 있다. 본 연구에서는, 능동소자로 높은 유전용량을 갖는 적층 세라믹 콘덴서(X7R -55$^{\circ}C$~1$25^{\circ}C$)에 대한 가속열화시험을 실시하고, 정격온도의 최대치에서 다른 배율의 전압을 인가하여 단순선형회귀에 의한 특성치의 경시변화를 설명한다고 가정하였다. 최소제곱법을 적용하여 시료가 대수정규분포를 따를 때의 열화량을 설명한 후, 특성치-시간간의 선형관계 및 대수정규분포의 독립성을 검정하여 가정의 적절성을 검정하였다. 마지막으로 아이링모델에 의한 평균수명을 평가하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.1-5
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• 2006

The effect of A/B moi ratios and sintering temperatures on dielectric properties and microstructure of $(Ba_{0.93}Ca_{0.07})_m(Ti_{0.82}Zr_{0.18})O_3$ ceramics were investigated. The dielectric constant decreased with increasing the A/B mol ratio. However, the dielectric loss is improved. As the dielectric properties of A/B mol ratio with m = 1.009 at sintered temperature $1260^{\circ}C$, we obtained dielectric constant 12,800, dielectric loss $3.5\%$ and Y5V temperature characteristics. Highly reliable Ni-MLCCs, 1.6mm$(length){\time}0.8mm(width){\time}0.8mm$(height) with capacitance of 1.23 ${\mu}F$ and 야ssipation loss of $5.2\%$ were obtained employing dielectric material composed of $(Ba_{0.93}Ca_{0.07})_{1.009}(Ti_{0.82}Zr_{0.18})O_3$ - $MnO_2\;0.2wt\%-Y_2O_3\;0.18wt\%,\;-\;SO_2\;0.15wt\%-(Ba_{0.4}Ca_{0.6})SiO_3\;1wt\%$.