Low Temperature Cofired Ceramics

Sebastian, Mailadil Thomas

doi:10.1016/b978-0-08-045330-9.00012-1

Cited by 12 publications

(5 citation statements)

References 296 publications

(383 reference statements)

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“…Low-temperature co-fired ceramics (LTCCs) are dielectric materials that can be co-fired with Ag or Cu, which are metals that exhibit low-resistance conduction at temperatures below their melting points (961 and 1084 °C, respectively) [ 1 , 2 ]. LTCCs have been widely used in small electronic devices, such as wiring substrates and integrated circuit packages for high-frequency communication.…”

Section: Introductionmentioning

confidence: 99%

Solid-State-Activated Sintering of ZnAl2O4 Ceramics Containing Cu3Nb2O8 with Superior Dielectric and Thermal Properties

2022

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Low-temperature co-fired ceramics (LTCCs) are dielectric materials that can be co-fired with Ag or Cu; however, conventional LTCC materials are mostly poorly thermally conductive, which is problematic and requires improvement. We focused on ZnAl2O4 (gahnite) as a base material. With its high thermal conductivity (~59 W·m−1·K−1 reported for 0.83ZnAl2O4–0.17TiO2), ZnAl2O4 is potentially more thermally conductive than Al2O3 (alumina); however, it sinters densely at a moderate temperature (~1500 °C). The addition of only 4 wt.% of Cu3Nb2O8 significantly lowered the sintering temperature of ZnAl2O4 to 910 °C, which is lower than the melting point of silver (961 °C). The sample fired at 960 °C for 384 h exhibited a relative permittivity (εr) of 9.2, a quality factor by resonant frequency (Q × f) value of 105,000 GHz, and a temperature coefficient of the resonant frequency (τf) of −56 ppm·K−1. The sample exhibited a thermal conductivity of 10.1 W·m−1·K−1, which exceeds that of conventional LTCCs (~2–7 W·m−1·K−1); hence, it is a superior LTCC candidate. In addition, a mixed powder of the Cu3Nb2O8 additive and ZnAl2O4 has a melting temperature that is not significantly different from that (~970 °C) of the pristine Cu3Nb2O8 additive. The sample appears to densify in the solid state through a solid-state-activated sintering mechanism.

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Section: Introductionmentioning

confidence: 99%

Solid-State-Activated Sintering of ZnAl2O4 Ceramics Containing Cu3Nb2O8 with Superior Dielectric and Thermal Properties

2022

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“…This is also a perovskite-type material with a high insulation resistance and advantageous dielectric properties [ 5 ]. As a result of their high dielectric permittivity and low dielectric loss, BaTiO 3 , its SrTiO 3 counterpart, and their BaSrTiO 3 compositions are the most common dielectric ceramics used in communication [ 6 ], micro- and nano-electronics [ 7 ], or new generation photonics [ 8 ]. However, for 3D printing technology and other flexible device applications, the poor flexibility of BaTiO 3 , SrTiO 3 , and BaSrTiO 3 limits their applications at a large scale.…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Ceramic Nanoparticles on the Thermoplastic Polymers Matrix: Their Structural, Optical, and Conductive Properties

et al. 2021

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This paper prepared composites under the free membranes form that are based on thermoplastic polymers of the type of polyurethane (TPU) and polyolefin (TPO), which are blended in the weight ratio of 2:1, and ceramic nanoparticles (CNs) such as BaSrTiO3 and SrTiO3. The structural, optical, and conductive properties of these new composite materials are reported. The X-ray diffraction studies highlight a cubic crystalline structure of these CNs. The main variations in the vibrational properties of the TPU:TPO blend induced by CNs consist of the following: (i) the increase in the intensity of the Raman line of 1616 cm−1; (ii) the down-shift of the IR band from 800 to 791 cm−1; (iii) the change of the ratio between the absorbance of IR bands localized in the spectral range 950–1200 cm−1; and (iv) the decrease in the absorbance of the IR band from 1221 cm−1. All these variations were correlated with a preferential adsorption of thermoplastic polymers on the CNs surface. A photoluminescence (PL) quenching process of thermoplastic polymers is demonstrated to occur in the presence of CNs. The anisotropic PL measurements have highlighted a change in the angle of the binding of the TPU:TPO blend, which varies from 23.7° to ≈49.3° and ≈53.4°, when the concentration of BaSrTiO3 and SrTiO3 CNs, respectively, is changed from 0 to 25 wt. %. Using dielectric spectroscopy, two mechanisms are invoked to take place in the case of the composites based on TPU:TPO blends and CNs, i.e., one regarding the type of the electrical conduction and another specifying the dielectric–dipolar relaxation processes.

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“…Low-temperature co-fired ceramics (LTCCs) have been attracting attention over recent decades due to rapid advances in wireless telecommunications, including the 5th generation (5G) tactile internet and the Internet of Things (IoT) [ 1 ]. LTCCs have characteristics that require sintering at temperatures of less than 1000 °C in order to be co-fired with electrode materials, such as Cu (melting point: 1083 °C), Ag (melting point: 961 °C), or Au (melting point: 1061 °C) [ 2 ]. LTCC devices provide a solution for integrating passive components, e.g., capacitors and resistors, with these electrodes into a three-dimensional module at the same time.…”

Section: Introductionmentioning

confidence: 99%

Exploring Dielectric Constant and Dissipation Factor of LTCC Using Machine Learning

Liu

Huang

et al. 2021

Materials

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Low-temperature co-fired ceramics (LTCCs) have been attracting attention due to rapid advances in wireless telecommunications. Low-dielectric-constant (Dk) and low-dissipation-factor (Df) LTCCs enable a low propagation delay and high signal quality. However, the wide ranges of glass, ceramic filler compositions, and processing features in fabricating LTCC make property modulating difficult via experimental trial-and-error approaches. In this study, we explored Dk and Df values of LTCCs using a machine learning method with a Gaussian kernel ridge regression model. A principal component analysis and k-means methods were initially performed to visually analyze data clustering and to reduce the dimension complexity. Model assessments, by using a five-fold cross-validation, residual analysis, and randomized test, suggest that the proposed Dk and Df models had some predictive ability, that the model selection was appropriate, and that the fittings were not just numerical due to a rather small data set. A cross-plot analysis and property contour plot were performed for the purpose of exploring potential LTCCs for real applications with Dk and Df values less than 10 and 2 × 10−3, respectively, at an operating frequency of 1 GHz. The proposed machine learning models can potentially be utilized to accelerate the design of technology-related LTCC systems.

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Low Temperature Cofired Ceramics

Cited by 12 publications

References 296 publications

Solid-State-Activated Sintering of ZnAl2O4 Ceramics Containing Cu3Nb2O8 with Superior Dielectric and Thermal Properties

Solid-State-Activated Sintering of ZnAl2O4 Ceramics Containing Cu3Nb2O8 with Superior Dielectric and Thermal Properties

The Influence of the Ceramic Nanoparticles on the Thermoplastic Polymers Matrix: Their Structural, Optical, and Conductive Properties

Exploring Dielectric Constant and Dissipation Factor of LTCC Using Machine Learning

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