玻璃添加對於鈦酸鎂鈣(Mg,Ca)TiO3微波介電性質的影響

Abstract

近來，為了要增加高頻積層電容的應用範圍，對於其生產成本的降低，體積的微小化，高電容值以及高可靠度的需求便非常迫切。其中，生產成本的降低是工業製造的最重要考量因素。而積層電容中的電極材料的成本佔總成本很大的部份，目前工業上常用的最主要內電極材料為鈀電極或銀－鈀電極。因此降低介電材料的燒結溫度，使其能夠和低耗損且低成本金屬如銀，銅或金等作低溫共燒，是非常迫切需要的。 本論文是用Kyorix公司提供的鈦酸鎂鈣粉末作為主材料(Host material)，其燒結溫度為1267℃。數種玻璃包括B2O3 , ZnO-B2O3系統，MgO-Al2O3-SiO2系統和B2O3-SiO2系統被加入到主材料中，以降低其燒結溫度。加入5wt% MgO-Al2O3-SiO2系統和10wt% ZnO-B2O3系統的鈦酸鎂鈣的燒結溫度可以降至1100℃且依然擁有很好的微波特質。 本實驗亦利用氧化銅作為助燒劑以進一步降低燒結溫度，加入10wt%的ZnO-B2O3以及0.25wt%的氧化銅，其燒結溫度可以降至1050℃，微波性質如下：介電常數＝20.02, Q ´ f = 47611.6，對應Qd = 5360.47 於8.88GHz；此燒結溫度低於銅的熔點，因此與銅作低溫共燒是可行的。 樣本的微波介電性質和其結晶情況，微結構以及緻密度的關係將被研究。

Recently, reduction of production cost, miniaturization, high capacitance, and high reliability are the requirements needed for these multilayer devices in order to increase the range of high frequency applications of capacitors. Among these requirements, low cost is of prime importance from the views point of industrial product. The cost of the electrode materials occupies a large part of the total cost. So far, palladium or silver-palladium has been the majority of the internal electrode material. It is imperative to lower the sintering temperature of the dielectric in order to co-fire with low loss conducting and less expensive base-metal materials such as silver, copper or gold. A commercial powder of (Mg, Ca )TiO3 supplied by Kyorix was used as a host material in this study, and its sintering temperature was 1267℃. Several glasses including B2O3 , ZnO-B2O3 system, MgO-Al2O3-SiO2 system and B2O3-SiO2 system were added into the host material in order to reduce the sintering temperature. The sintering temperatures of (Mg, Ca)TiO3 sintered with 5wt% of MgO-Al2O3-SiO2 addition and 10wt% of ZnO-B2O3 glass system addition were decreased to 1100℃ and still possessed a good microwave dielectric properties. The copper oxide ( CuO ) was used as a sintering aid in order to reduce the sintering temperature. The sintering temperature of (Mg, Ca )TiO3 sintered with 10wt% of ZnO-B2O3 glass system and 0.25wt% of CuO doping was decreased to 1050℃. It possessed the following microwave dielectric properties : dielectric constant = 20.02, Q × f = 47611.6, corresponds to Qd = 5360.47 at 8.88 GHz. It is possible to co-fire with these low loss metal. The co-relation between the microwave dielectric properties and crystallographic, microstructure and densification of the samples were investigated. 中 文 摘 要………………………………………………………………………...i Abstract in English………………………………………………………………...iii 誌 謝 …………………………………………………………………………….v Contents……………………………………………………………………………..vi List of Tables……………………………………………………….……………….x Figures Caption…………………………………………………………………….xi Chapter 1 Introduction…………………………………….……………..…1 Chapter 2 Literature Review………………………..……………………..7 2-1 Electromagnetic Theory……………………………………………………..7 2-1-1 Electromagnetic Fields in Dielectric Rod Waveguide…….……………7 2-1-2 The Eigenvalue Equation……………………………………………..15 2-1-3 Dielectric Rod Resonator with Parallel Conducting Plates …………..18 2-1-4 Graphical Method Predicting the Resonance Mode and Frequencies...20 2-1-5 The Field Distribution of TE01 Mode in a Parallel-Plate Dielectric Resonator………………………………………………...22 2-2 The Measurement of Microwave Properties of Ceramics Material using Parallel-Plate Dielectric Rod Resonator…………………………….26 2-2-1 Definition of Quality Factor ( Q )……………………….…………….28 2-2-2 The Classification of Quality Factor…………………….……………30 2-2-3 The Measurement of Dielectric Properties of Microwave Ceramics – The Hakki and Coleman Method…………………………………35 2-3 Dielectric Properties………………………………………………………..44 2-3-1 Dielectric Constant…………………………………………………....44 2-3-2 Frequency Dependence………………………………….…………….46 2-3-3 Temperature Dependence……………………………………………..50 2-4 Microwave Dielectric Material and Application…………….……………..51 2-4-1 Application of Microwave Ceramics………………………………….51 2-4-2 Multilayer Ceramic capacitors ( MLCCs )……………………………55 2-4-3 Low Temperature Co-fire Ceramic – (Mg, Ca)TiO3…….……………60 2-4-4 Microwave Properties of Glasses……………………………………...66 2-4-5 The Effect of Glass Content in Microwave Ceramics ………………..67 Chapter 3 Experimental Procedure……………………………………...68 3-1 Sample Preparation………………………………………….……………..68 3-2 Density Measurement and Calculation…………………………………….69 3-3 Microwave Dielectric Measurement……………………………………….69 3-3-1 Measurement Procedure……………………………………………….69 3-3-2 The Identification of Resonant Mode in the Resonator….……………70 3-3-3 Calculation of Microwave Dielectric Properties………………………70 3-3-4 Temperature Coefficient of Frequency………………………………..71 3-4 Crystallographic and Microstructure Measurement………………………..72 Chapter 4 Results and Discussions……………………………….……..73 4-1 Densification and Microwave Dielectric Properties of(Mg,Ca)TiO3……….73 4-1-1 Microwave Dielectric Properties………………………………………73 4-1-2 Crystallographic Structure and Microstructure ………….……………78 4-2 Densification and Microwave Dielectric Properties of (Mg, Ca)TiO3 with B2O3 addition………………………………………………………...78 4-2-1 Microwave Dielectric Properties………………………………………78 4-2-2 Crystallographic Structure and Microstructure ………….……………85 4-3 Densification and Microwave Dielectric Properties of (Mg, Ca)TiO3 with ZnO-B2O3 addition…………………………………………………..90 4-3-1 Microwave Dielectric Properties………………………………………90 4-3-2 Crystallographic Structure and Microstructure ………….……………95 4-4 Densification and Microwave Dielectric Properties of (Mg, Ca)TiO3 with MgO-Al2O3-SiO2 addition………………………………………….104 4-4-1 Microwave Dielectric Properties……………………………………..104 4-4-2 Crystallographic Structure and Microstructure ………….…………..112 4-5 Densification and Microwave Dielectric Properties of (Mg, Ca)TiO3 with B2O3-SiO2 addition………………….……………………………...118 4-5-1 Microwave Dielectric Properties……………………………………..118 4-5-2 Crystallographic Structure and Microstructure ………….…………..121 4-6 Densification and Microwave Dielectric Properties of (Mg, Ca)TiO3 sintered with ZnO-B2O3 glass system and Doping of Copper Oxide……124 4-6-1 Microwave Dielectric Properties……………………………………..124 4-6-2 Crystallographic Structure and Microstructure ………….…………..130 Chapter 5 Conclusions…………………………………………………..136 References …………………………………………………………………...138 Vita …………………………………………………………………..143