Wang Wei, Shehbaz Muhammad, Wang Xin, Du Chao, Xu Diming, Shi Zhong-Qi, Darwish Moustafa Adel, Qiu Hong-Song, Jin Biao-Bing, Zhou Tao, Chen Ya-Wei, Liang Qi-Xin, Zhang Mei-Rong, Zhou Di
Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi China.
State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, Shaanxi China.
ACS Appl Mater Interfaces. 2023 Nov 8;15(44):51453-51461. doi: 10.1021/acsami.3c13668. Epub 2023 Oct 30.
In developing low-temperature cofired ceramic (LTCC) technology for high-density packaging or advanced packaged electronics, matching the coefficient of thermal expansion (CTE) among the packaged components is a critical challenge to improve reliability. The CTEs of solders and organic laminates are usually larger than 16.0 ppm of °C, while most low-permittivity (ε) dielectric ceramics have CTEs of less than 10.0 ppm °C. Therefore, a good CTE match between organic laminates and dielectric ceramics is required for further LTCC applications. In this paper, we propose a high-CTE BaSO-BaF LTCC as a potential solution for high-reliability packaged electronics. The BaSO-BaF ceramics have the advantages of a wide low-temperature sintering range (650-850 °C), low loss, temperature stability, and Ag compatibility, ensuring excellent performance in LTCC technology. The 95 wt %BaSO-5 wt %BaF ceramic has a ε of 9.1, a × of 40,100 GHz @11.03 GHz ( = 1/tan δ), a temperature coefficient of the resonant frequency of -11.2 ppm °C, a CTE of +21.8 ppm °C, and a thermal conductivity of 1.3 W mK when sintered at 750 °C. Furthermore, a dielectric resonant antenna using BaSO-BaF ceramics, a typically packaged component of LTCC and laminate, was designed and used to verify the excellent performance by a gain of 6.0 dBi at a central frequency of 8.97 GHz and a high radiation efficiency of 90% over a bandwidth of 760 MHz. Good match and low thermal stress were found in the packaged components of BaSO-BaF ceramics, organic laminates, and Sn-based solders by finite element analysis, proving the potential of this LTCC for high-reliability packaged electronics.
在开发用于高密度封装或先进封装电子产品的低温共烧陶瓷（LTCC）技术时，使封装组件之间的热膨胀系数（CTE）相匹配是提高可靠性的一项关键挑战。焊料和有机层压板的CTE通常大于16.0 ppm/°C，而大多数低介电常数（ε）介电陶瓷的CTE小于10.0 ppm/°C。因此，对于进一步的LTCC应用，需要有机层压板和介电陶瓷之间有良好的CTE匹配。在本文中，我们提出一种高CTE的BaSO-BaF LTCC作为高可靠性封装电子产品的潜在解决方案。BaSO-BaF陶瓷具有低温烧结范围宽（650-850°C）、低损耗、温度稳定性和与银兼容性好等优点，确保了在LTCC技术中的优异性能。95 wt%BaSO-5 wt%BaF陶瓷在750°C烧结时，ε为9.1，在11.03 GHz时的品质因数（Q×f）为40100 GHz（Q = 1/tanδ），谐振频率温度系数为-11.2 ppm/°C，CTE为+21.8 ppm/°C，热导率为1.3 W/(m·K)。此外，设计了一种使用BaSO-BaF陶瓷的介质谐振天线，它是LTCC和层压板的典型封装组件，并通过在8.97 GHz中心频率处增益为6.0 dBi以及在760 MHz带宽内具有90%的高辐射效率来验证其优异性能。通过有限元分析发现，在BaSO-BaF陶瓷、有机层压板和锡基焊料的封装组件中具有良好的匹配和低热应力，证明了这种LTCC在高可靠性封装电子产品方面的潜力。
