Colloidal Processing and Microstructural Design of Glass- Ceramic Composites

Prashant Kumta 摘要 当前和未来封装技术的重点是实现高器件密度。 这些发展对基板技术提出了严格的要求。 基板需要具有良好的散热和信号传播特性。 为了使设备输出特性与过程的经济性相匹配，一些折衷似乎至关重要。 具有最佳热性能和介电性能的复合材料将为该问题提供理想的解决方案。 提出了一种胶体加工技术与独特的微观结构设计相结合，以加工具有最佳热性能和电性能的玻璃陶瓷复合材料。 提出利用廉价金属氧化物前体的改进金属氧化物溶胶-凝胶（MOSG）工艺来合成硼磷硅酸盐玻璃陶瓷。 将使用原位溶液涂覆技术来引入导热第二相。 将启动对温度、溶液粘度、烧结时间和体积分数等加工参数的系统控制，以在含有连续导热相网络的致密复合材料中产生双相微观结构。 该研究的三个主要目标是：（1）使用改进的溶液方法合成微晶玻璃复合材料（2）系统研究和控制微晶玻璃复合材料演化的微观结构，（3）利用热分析、X射线衍射、扫描和透射电子显微镜了解凝胶结构和工艺变量（体积分数、涂层厚度、凝胶结构、烧结时间、温度）对微结构及其性能的影响。 微观结构对电性能和热性能的影响也将通过测量致密复合材料的介电常数、热膨胀和导热系数来评估。 本方法提供了一种处理具有连续微观结构的双相复合材料的新方法，并且可以很容易地扩展到处理用于电子和结构应用的其他玻璃陶瓷、陶瓷陶瓷或金属陶瓷复合材料。 ***

Prashant Kumta Abstract The current and future emphasis in packaging technology are aimed at achieving high device densities. These development place stringent requirements on substrate technology. The substrates need to possess good heat dissipation and signal propagation characteristics. Several compromises seem to be essential to match the device output characteristics with the economics of the process. A composite material with optimum thermal and dielectric properties would offer an ideal solution to this problem. A colloidal processing technique combined with a unique microstructural design is proposed to process a glass-ceramic composite with optimum thermal and electrical properties. Modified metal oxide sol-gel (MOSG) process utilizing inexpensive metal oxide precursors is proposed to synthesize borophosphosilicate glass-ceramics. An in-situ solution coating technique will be used to introduce the thermally conducting second phase. Systematic control of the processing parameters such as temperature, solution viscosity, sintering time, and volume fraction will be initiated to generate a duplex microstructure in the dense composite containing a continuous network of the thermally conducting phase. The three main objectives of the proposed study are: (1) Synthesis of the glass-ceramic composite material using the modified solution approach (2) Systematic study and control of the evolved microstructure of the glass-ceramic composite and (3) To understand the effect of the gel structure and the process variables (volume fraction, coating thickness, gel structure, sintering time, temperature) on the microstructure and its properties, using thermal analyses, X-ray diffraction, scanning and transmission electron microscopy. The effect of the microstructure on the electrical and thermal properties will also be assessed by measuring the dielectric constant, thermal expansion and thermal conductivity of the dense composites. The present approach offers a novel method to process dual phase composites with a contiguous microstructure and can be easily extended to process other glass- ceramic, ceramic-ceramic or metal- ceramic composites for electronic and structural application. ***