高品质低介微波介质材料的制备及其应用

发布时间：2018-04-20 07:28

  本文选题：介电性能 + 品质因数　； 参考：《西安电子科技大学》2015年硕士论文

【摘要】：低温共烧陶瓷(Low Temperature Co-fired Ceramics LTCC)技术已成为实现各类电子元器件制造、集成及其封装的主流技术,低介电常数微波介质陶瓷由于其介电常数低、品质因数高、温度系数近似为零等优点被广泛应用于LTCC基板材料中,成为微波介质陶瓷研究的热点。本论文中选取CaO-SiO_2-B_2O_3作为研究体系,采用多步固相法制备低介电常数微波介质陶瓷材料,分别研究了Ca/Si比和B_2O_3的改变对材料晶相组成、微观形貌和介电性能的影响。在最佳Ca/Si比和适当B_2O_3含量的基础上,添加适量陶瓷助溶剂BBAS粉,以降低陶瓷粉体的烧结温度,最终获得可用于制备LTCC基板材料的陶瓷粉料。采用X-射线衍射(XRD)法、扫描电子显微镜(SEM)、阿基米德原理和Zeta电位分析对陶瓷粉料的物相、表面形貌、密度和Zeta电位进行表征。精选CBS陶瓷粉体后通过不断调配浆料配比和工艺参数,采用流延工艺制备出可应用的LTCC生瓷带,在此基础上制备LC谐振天线,并对其谐振频率进行测试。研究结果表明,当CaO:SiO_2:B_2O_3=21:13:16(质量比),煅烧温度为900℃时,所得样品C中除了有主晶相b-CaSiO3和Ca2B_2O_4外,含有少量a-SiO_2相。由该粉体制备的陶瓷样品中,晶粒以板条状为主,晶粒间气孔较少,结构比较致密,具有较大的密度。此时该样品具有最佳的介电性能,其介电常数为6.3、品质因数为2.4×104GHz(f=11.7 GHz)、温度系数为-67 ppm/℃,热导率为3.6W/m×K。在样品C的配方基础上,添加适量陶瓷助溶剂BBAS粉,以降低该组分的烧结温度。研究发现,添加陶瓷助溶剂BBAS粉后,晶体的结构没有明显改变,晶粒的形貌仍以板条状的为主,一些小的粒状晶粒分散在其中。当烧结温度降低至920℃时,所得陶瓷样品C_6的晶粒粒径介于1.0-2.0mm之间,并且陶瓷颗粒在水溶液中显负电性,颗粒之间的稳定性较差。该样品具有较好的介电性能,其介电常数为6.3,品质因数为1.1×104 GHz(f=12.7 GHz),温度系数为-84 ppm/℃。以所得陶瓷粉料C_6为填充物,有机物(乙酸乙酯和酒精的混合物)作为溶剂,通过调节粘结剂PVB和增塑剂的含量,制备不同配比的流延浆料。采用流延法制备LTCC生瓷带,再经丝网印刷、打孔、叠层、温水等静压、排胶、共烧等LTCC工艺后,通过CAD绘图,制备可用于测试应变的LC谐振天线,并采用接触法和非接触法测试其共振频率。结果表明,所制备的天线的共振频率约为f=155 MHz,与设计目标f=120MHz接近。
[Abstract]:Low Temperature Co-fired Ceramics LTCC (low temperature Temperature Co-fired Ceramics LTCC) technology has become the mainstream technology to realize the fabrication, integration and packaging of all kinds of electronic components. The low dielectric constant microwave dielectric ceramics have high quality factor due to their low dielectric constant. The temperature coefficient is approximately zero and has been widely used in LTCC substrate materials, and has become a hot spot in microwave dielectric ceramics research. The low dielectric constant microwave dielectric ceramics were prepared by multi-step solid state method with CaO-SiO_2-B_2O_3 as the research system. The effects of the changes of Ca/Si ratio and B_2O_3 on the crystal phase composition, microstructure and dielectric properties of the materials were studied. On the basis of the optimum Ca/Si ratio and the appropriate B_2O_3 content, the proper amount of ceramic co-solvent BBAS powder was added to lower the sintering temperature of the ceramic powder, and finally the ceramic powder which could be used to prepare the LTCC substrate material was obtained. The phase, surface morphology, density and Zeta potential of ceramic powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes principle and Zeta potential analysis. After selecting the CBS ceramic powder, the suitable LTCC ceramic tape was prepared by continuous mixing of slurry ratio and technological parameters. On this basis, LC resonant antenna was prepared and its resonant frequency was measured. The results show that when Cao: Sio _ 2O _ 2: B _ 2O _ 2O population is 321: 13: 16 (mass ratio, calcination temperature is 900 鈩，

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