【作者】 张启龙；

【导师】 杨辉；

【作者基本信息】 浙江大学 ， 材料学， 2004， 博士

【摘要】 以高速传榆数据并能传输图像为特征的第三代移动通信系统对通信设备提出了新的要求，同时也将引发新一代移动终端的革命。WCDMA、CDMA2000和TD-SCDMA作为3G标准已获得国际电联（ITU）的认可，将兼容第二代移动通信并在其基础上投入运营。因此移动通信终端必将要求满足多模式和多频段工作的需要。多模、多频段手机研制取决于先进的元器件，天线、滤波器等前端射频元器件是必不可少的关键元器件。传统的前端射频元器件设计理念已不能满足3G元器件的要求，基于低温共烧（LTCC）技术为基础的多层结构设计为研制3G天线、滤波器等先进射频元器件提供了解决方案。低温共烧技术关键是对能与银电极共烧的低温烧结微波介质陶瓷的研制，世界各国正在竞相开发。目前，部分体系的低温烧结微波介质陶瓷已经得到深入研究，并取得突破性进展，但由于材料特性、器件设计及制备工艺研究相互间脱节，研制的材料大都存在难以配制稳定料浆、与银电极发生化学反应等问题，真正具有应用价值的低温烧结微波介质陶瓷材料很少，加上多层结构微波设计和制造技术要求相当高，制约了多层片式微波频率器件发展，难以满足现代移动通信技术发展的要求。 本文首次采用材料特性、器件设计及制备工艺相结合的三位一体的研究模式，开发低温烧结微波介质陶瓷及其器件。 （一）结合材料烧结特性及介电性能，选择以Ca[(Li_1／3Nb_2／3)，Ti]O_3-σ（简称CLNT）、ZnO-Nb₂O₅-TiO₂（简称ZNT）、ZnO-TiO₂（简称ZT）、Li₂O-Nb₂O₅-TiO₂（简称LNT）陶瓷为基体材料，根据添加剂与基体材料的润湿特性以及多层器件对料浆特性与陶瓷-银电极共烧要求，优化烧结助剂和工艺，制备出几种介电性能优良的具有应用价值的低温烧结微波介质陶瓷。（1）复合添加ZnO，Bi₂O₃和ZnO-B₂O₃-SiO₂玻璃（简称ZBS玻璃）粉制备低温烧结CLNT陶瓷，在920℃烧结，微波介电性能：ε_r=37.8，Q·f=11000GHz，τ_f=12×10^-6／℃。（2）从基础成分TiO₂、改性剂SnO₂和烧结助剂方面协调介电性能，并采用CuO，V₂O₅协同降低ZNT陶瓷烧结温度，获得烧结温度860℃、介电性能：ε_r=42.3，Q·f=9000GHz，τ_f=8×10^-6／℃的陶瓷。（3）独创以溶胶-凝胶形式引入ZnO-B₂O₃-SiO₂制备低温烧结ZT陶瓷，获得烧结温度900℃、介电性能：ε_r=27.05，Q·f=20000GHz，τ_f=8×10^-6／℃的陶瓷。（4）采用V₂O₅和ZBS玻璃协同降低LNT陶瓷烧结温度，并协调介电性能，制备出烧结温度900℃，介电性能：ε_r=57，Q·f=4420GHz，τ_f=3×10^-6／℃的陶瓷。实现了低温烧结微波介质陶瓷系列化，陶瓷材料能配制成稳定的料浆，与银电极具有良好的界面结合状态，可满足不同频率段多层微波频率器件使用要求。 （二）结合微波介质陶瓷的低温烧结特性及相组成，揭示出液相低温烧结润湿机制，为烧结助剂的选择提供依据。研究表明:（1）选择与基体材料相溶的低熔点物质是实现低温烧结的有效途径。添加1.swto/hcuo一v20，的zNT陶瓷可在860℃致密烧结，降温效果明显优于熔点相对较高的Cuo、FevO;氧化物;添加vZo，的1.swt%的LNT陶瓷的致密化温度可降至900oC，而CLNT陶瓷采用Cuo、V205降温效果不明显。（2）液相添加剂与固体颗粒间发生界面反应可提供良好的润湿效果。添加V20、的LNT陶瓷和添加Bi20;的CLNT陶瓷，发生界面反应分别生成LIVO:和Ti认一Bi 20。低熔点界面化合物，氧化物产生的液相以及界面化合物生成的液相两重润湿固体颗粒，有效降低陶瓷的烧结温度。（3）单一助剂难以实现低温烧结或栖牲介电特性才能降温的条件下，多种方式复合添加是实现低温烧结的理想途径。单独添加Bi 203的CLNT陶瓷，促进烧结有限，降温极限仍在1 020℃以上;在掺Bi 20。的基拙上，添加ZBS玻璃，烧结温度降至950℃以下，并抑制了单独添加Bi20。引起CLNT陶瓷相分裂现象。添加Zwt%V20。和lwt%V205+swt%ZBS均能促使LNT陶瓷烧结温度降至900℃，但单独添加Zwt%v20，的LNT陶瓷勺较大，而复合添加剂IWt%vZ仇十swt%ZBS降温的同时可协调孙解决了单一助剂无法兼顾低温烧结并保持良好介电特性的技术难题。 （三）揭示出添加剂分布状态对介电性能的影响机制。CLNT、ZNT、zT、L盯低温烧结微波介质陶瓷研究表明:（1）添加ZBS玻璃的CLNT、zT、LNT陶瓷，ZBS液相分布在晶粒和晶界处，降低。r和Q·f值，行向正频率温度系数方向移动;（2）Zn，‘和Sn“分别取代CLNT、ZNT陶瓷中Ca’‘和Ti“形成固溶体，6;下降，Q·f值各自在固溶极限值达到最大;而掺加Fevo;的 ZNT和掺加V20，的LNT陶瓷，V，‘取代Nbs十形成完全固溶体，微观状态混乱程度增加，Q·f值降低。（3）添加助剂的ZNT、zT陶瓷的相变温度发生变化，其E:，Q·f值，行与发生相变的相组成和介电特性密切相关。以掺杂ZBS的ZT陶瓷为例，添加ZBS后，促使ZnTIO3相分解温度从945℃降至9200C，生成znTi20;，Ti02，。:迅速增大，Q·f值急剧-f=降。（4）固相法引入zBS组分制备的低温烧结znTIO。瓷的er偏差士0.8，可满足模拟仿真允许偏差土1 .0的要求。采用溶胶一凝胶法引入ZBS组分，ZBS溶胶均匀包覆在ZnT 1 03颗粒表面，合成的粉体均匀可控;陶瓷6，偏?更多还原

【Abstract】 The third generation mobile communication system figured of high speed digital transmission and image transmission requires better performance of communication equipments. And it will generate a new revolution in mobile communication terminal. As the standards of 3G , WCDMA, CDMA2000 and TD-SCDMA were approved by ITU. These standards will be compatible with the second generation mobile communication system and work on the basis of the second. Therefore, the mobile communication terminal should work on the condition of multi-mode and multi-frequency. The research level of the mobiles mentioned above decided by the advanced components such as antennas and fileters which are the keypoints of the front-end RF components. The conventional design concept of front-end RF components can not fulfil the requirements of 3G components. Multilayer structure design based on LTCC technology provided a solution for advanced RF components such as 3G antennas and filters. The key technology of LTCC was the research on low temperature firing microwave dielectric ceramic which can cofire with silver electrode. Thus the research were developed all over the world. Presently, some systems of the ceramic has been investigated deeply and obtained some breakthrough. However, it was disjunct among material properties, components design and preparation technics. Most of the materials had various problems such as difficult to prepare stable slurry or reacting with silver electrode. Few low temperature firing microwave dielectric ceramics can put into practice. Since the restriction of materials and the high request of the design and manufacture technology in muti layer structure, the development of multilayer laminated microwave components were confined. It can not fulfil the requirement of development in mobile communication technology.The research mode that Combined material properties, components design and preparation technics was adopted for the first time and the microwave dielectric ceramic and the corresponding components were developed in this paper.According to their sintering characteristics and dielectric properties.ceramic systems of Ca[(Li,/3Nb2/3), TiJOjXCLNT for short), ZnO-Nb2O5-TiO2(ZNT for short), ZnO-TiO2(ZT for short), Li2O-Nb2O5-TiO2(LNT for short) were selected as the research objects Based on the wetting characteristics between sintering aids and the basis materials and the requirements of multilayer components on slurry property and cofiring of ceramic and silver electrode, the sintering aids and preparation processes were optimized; several kinds of low temperature firing microwave dielectric ceramics which had excellent properties and application value were acquired. (1) Low temperature sintering ceramic CLNT was prepared with multiple additions of ZnO,Bi2O3 and ZnO-B2O3-SiO2 glass(ZBS glass for short). It acquired microwave dielectric properties of r=37.8, Q ?f=11000GHz, r/=12 10~VC sintered at 920 . (2)The ZNT ceramic dielectric properties was modificated by main constituent TiO2,modifying agent SnO2, and sintering aids and its sintering temperature decreased by CuO, V2O5 addition. It acquired microwave dielectric properties of e r=42.3, Q ?f=9000GHz, 77=8 x 10"6/ sintered at 860 . (3) The low temperature sintering ZT ceramic was prepared with ZnO-B2O3-SiO2 doped by sol-gel method for the first time. It acquired microwave dielectric properties of e r=27.05, Q -f=20000GHz, r/=8 IQsintered at 9001). (4) The LNT ceramic sintering temperature decreased and dielectric properties were modificated by V2Os and ZBS glass. It acquired microwave dielectric properties of e r=57, Q ?f=4420GHz, ry=3 x lO"6/ sintered at 900 . All the ceramic systems mentioned above realized a series of low temperature microwave dielectric ceramic, could prepare stable slurry, had a good interface bonding condition with silver electrode and meet the demand of multilayer microwave frequency components of the diffement frenquency.The wetting mechanism of liquid phase low temperature sintering was illustrated according to the low tempe更多还原