• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.563-566
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• 2000

The effect of CuO and CuO-B $i_2$ $O_3$ additives on microwave dielectric properties of (P $b_{0.45}$C $a_{0.55}$)[F $e_{0.5}$N $b_{0.5}$)$_{0.9}$S $n_{0.1}$] $O_3$were investigated to decrease the sintering temperature for usage of Low Temperature Co-firing Ceramics (LTCC). The (P $b_{0.45}$C $a_{0.55}$)[F $e_{0.5}$N $b_{0.5}$)$_{0.9}$S $n_{0.1}$] $O_3$ceramics was sintered at 11$65^{\circ}C$. In order to decrease the sintering temperature, CuO and Cuo-B $i_2$ $O_3$ were added in the (Pb,Ca)[(Fe,Nb)Sn] $O_3$ with CuO-B $i_2$ $O_3$. For the addition of 0.4 wt.% CuO, the sintered density and the dielectric constant of the ceramics were revealed the maximum values of the 6.06g/c $m^2$ and 83 respectively and temperature coefficient of resonance frequency ($\tau$$_{f}$) shifted to the positive value. As increasing B $i_2$ $O_3$to the (Pb,Ca)[(Fe,Nb)Sn] $O_3$ with CuO-B $i_2$ $O_3$with 0.2 wt.% CuO, the sintered density, the $\varepsilon$$_{r}$ and the Q was decreased, and $\tau$$_{f}$ was minimized at 0.2 wt.% CuO, and 0.2 wt.% B $i_2$ $O_3$. For this composition, dielectric properties were $\varepsilon$$_{r}$ of 81, Q. $f_{0}$ of 4400 GHz, and $\tau$$_{f}$ of 5 ppm/$^{\circ}C$ at sintering temperature of 100$0^{\circ}C$. the relationship between the microstructure and properties of ceramics was studied by X-ray diffraction(XRD), scanning electron microscopy(SEM).copy(SEM).oscopy(SEM).copy(SEM).EM).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.297-297
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• 2007

The $(B_{0.5},Sr_{0.5})TiO_3$ ceramics, which added with low sintering materials $Li_2CO_3$ and ZnBO, was investigated for LTCC(low temperature co-fired ceramic) applications. To compare sintering temperature of $(B_{0.5},Sr_{0.5})TiO_3$ respectively, we added 1, 2, 3, 4, and 5wt% of $Li_2CO_3$ and ZnBO to $(B_{0.5},Sr_{0.5})TiO_3$. For confirming the sintering temperature, the respective specimens were sintered from $750^{\circ}C$ to $1200^{\circ}C$ by $50^{\circ}C$. The case of $Li_2CO_3$ greatly lowered the sintering temperature of $(B_{0.5},Sr_{0.5})TiO_3$ ($1350^{\circ}C$) below $900^{\circ}C$. The addition of ZnBO improved the loss tangent of $(B_{0.5},Sr_{0.5})TiO_3$. The crystalline structure of $LiCO_3$ doped $(B_{0.5},Sr_{0.5})TiO_3$ and ZnBO doped $(B_{0.5},Sr_{0.5})TiO_3$ was analyzed with the X-ray diffraction (XRD) analysis. The dielectric permittivity and loss tangent of $Li_2CO_3$ doped BST and ZnBO doped BST were measured with the HP 4284A precision. From the electrical characterization, we respectively obtained the dielectric permittivity 1361, loss tangent $6.94{\times}10^{-3}$ at $Li_2CO_3$ doped $(B_{0.5},Sr_{0.5})TiO_3$ (3wt%) and the dielectric constant 1180, loss tangent $3.70{\times}10^{-3}$ at ZnBO doped $(B_{0.5},Sr_{0.5})TiO_3$(5wt%).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.838-841
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• 2004

[ $B_2O_3$ ] added $Ba(Mg_{1/3}Nb_{2/3})O_3$ (BBMN) ceramics were not sintered below $900^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at $850^{\circ}C$. The amount of the $Ba_2B_2O_5$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the $B_2O_3$ inhibiting the reaction between $B_2O_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and $B_2O_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density the dielectric constant $({\varepsilon}_r)$ and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf=21500 GHz, ${\varepsilon}_r=31$ and temperature coefficient of resonance frequency$({\tau}_f)=21.3\;ppm/^{\circ}C$ were obtained for the $Ba(Mg_{1/3}Nb_{2/3})O_3+2.0\;mol%B_2O_3+10.0$ mol%CuO ceramic sintered at $875^{\circ}C$ for 2h.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.4
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• pp.79-85
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• 2023

A novel low-temperature co-fired ceramic (LTCC) dielectric, composed of (1-4x)Bi_1.5Zn_1.0Nb_1.5O₇-3xBi₂Zn_2/3Nb_4/3O₇-2xLiZnNbO₄ (x=0.03-0.21), was synthesized through reactive liquid phase sintering of Bi_1.5Zn_1.0Nb_1.5O₇-xLi₂CO₃ ceramic at temperatures ranging from 850℃ to 920℃ for 4 hours. During sintering, Li₂CO₃ reacted with Bi_1.5Zn_1.0Nb_1.5O₇, resulting in the formation of Bi₂Zn_2/3Nb_4/3O₇, and LiZnNbO₄. The resulting sintered body exhibited a relative sintering density exceeding 96% of the theoretical density. By altering the initial Li₂CO₃ content (x) and consequently modulating the volume fraction of Bi_1.5Zn_1.0Nb_1.5O₇, Bi₂Zn_2/3Nb_4/3O₇, and LiZnNbO₄ in the final sintered body, a sample with high dielectric constant (ε_r), low dielectric loss (tan δ), and the temperature coefficient of dielectric constant (TCε) characterized by NP0 specification (TCε ≤ ±30 ppm/℃) was achieved. As the Li₂CO₃ content increased from x=0.03 mol to x=0.15 mol, the volume fraction of Bi₂Zn_2/3Nb_4/3O₇ and LiZnNbO₄ in the composite increased, while the volume fraction of Bi_1.5Zn_1.0Nb_1.5O₇ decreased. Consequently, the dielectric constant (εr) of the composite materials varied from 148.38 to 126.99, the dielectric loss (tan δ) shifted from 5.29×10^-4 to 3.31×10^-4, and the temperature coefficient of dielectric constant (TCε) transitioned from -340.35 ppm/℃ to 299.67 ppm/℃. A dielectric exhibiting NP0 characteristics was achieved at x=0.09 for Li₂CO₃, with a dielectric constant (ε_r) of 143.06, a dielectric loss (tan δ) value of 4.31×10^-4, and a temperature coefficient of dielectric constant (TCε) value of -9.98 ppm/℃. Chemical compatibility experiment with Ag electrode revealed that the developed composite material exhibited no reactivity with the Ag electrode during the co-firing process.