【作者】 张文学；

【导师】 程晓农；

【作者基本信息】 江苏大学 ， 材料学， 2008， 硕士

【摘要】 现代电子信息技术飞速发展,对电子产品的小型化、便携化、多功能和高可靠性等提出了越来越高的要求。芯片集成度的迅速增加,必然导致发热量提高,电路的工作温度不断上升。同时,元器件封装成型后,由于材料线膨胀系数不同,成型固化收缩导致封装器件内部产生热应力,将造成强度下降、耐热冲击差、开裂离层等缺陷。此时,开发一种既具有高导热系数、低热膨胀系数又具有良好电学、力学等综合性能的新型封装材料,使电子元器件能在正常的温度范围内稳定地工作就显得非常重要。由于塑料封装具有质轻、成本低、成型工艺简单和耐冲击性能好等优点,其使用已占到整个封装材料的95%以上,其中环氧树脂基电子封装材料（简称环氧塑封料）又占塑料封装的90%左右,特别是近年来,国内外新型环氧塑封料的发展非常迅速。在此背景下,本文用固相反应法合成了负热膨胀填料—ZrW₂O₈粉体,与另一种高导热纳米氮化铝填料混杂添加到邻甲酚甲醛线性环氧树脂基体中,制备出一种高导热低膨胀的环氧塑封料。分析比较了ZrW₂O₈粉体和纳米AlN的用量、粒径、配比和表面处理方法等对复合材料热膨胀系数、导热系数、电学性能和弯曲力学性能的影响,结果表明:ZrW₂O₈粉体的大量引入对复合材料热膨胀系数的降低效果明显,纳米AlN粉体的引入可大大提高复合材料的导热系数,混杂添加50%微米级ZrW₂O₈和50%纳米级AlN,可将复合材料的热膨胀系数降低到0.87x10^-5/K,是无填料固化体系下的12.0%;同时,材料的导热系数由0.218W·m^-1·K^-1提高到3.885 W·m^-1·K^-1,变为原来的17.8倍;调整两种填料的用量及配比,可根据不同封装要求在一定范围内制备出一系列可控导热系数和热膨胀系数的高性能电子封装材料。经分析比较各种添加成分用量及配比和工艺方法对所制复合材料综合性能的影响后,得出:混杂添加50%ZrW₂O₈和20%纳米AlN制得的环氧塑封料综合性能相对最好(导热系数为2.083 W·m^-1K^-1,是无填料固化体系下的9.6倍;热膨胀系数为1.25x10^-5/K,是无填料固化体系下的17.3%;弯曲强度为168.5 MPa,相比无填料固化体系提高了39.0%),在保证材料具有较好的电学性能和抵抗弯曲歼裂能力前提下,较大程度地提高了环氧塑封料的导热系数,降低了材料的热膨胀系数。更多还原

【Abstract】 With the rapid development of electronic information technology,multifunctional and high-performance encapsulating materials are required.Especially with the progress of microelectronics industry,heat-producing capability of electronic component increases greatly,leading to the need of electronic packaging materials with high thermal properties.Current encapsulating materials fail to meet the electronic industry requirement because of two main limitations:low thermal conductivity and high thermal expansion coefficient.The large coefficient mismatch of thermal expansion between the substrate and silicon chip would result in too much distortions during the thermal cycling.So it is one of the most important projects for electronic encapsulating materials to improve its thermal conductivity and reduce its thermal expansion coefficient.The usage of plastic package in electronic packaging materials accounts for above 95%because of its excellent performances,such as low density,low price,easy molding technology,excellent shock resistance and so on.Among the plastic packaging materials, modem epoxy electronic encapsulating materials have developed rapidly and reached about 90%of the total application in the past few years.Herein,ZrW₂O₈ powders with negative thermal expansion properties prepared via solid-state reaction method,together with high-thermal-conducting nano-A1N powders were used as inorganic fillers and mixed into o-cresol formaldehyde epoxy resin to improve the thermal performance of the resulting composites.Results indicated that the thermal expansion coefficient of the composites was greatly reduced by adding ZrW₂O₈ fillers,and the thermal conductivity was greatly improved with the adding of A1N fillers.The adding of 50% micrometer-ZrW₂O₈ and 50%nano-A1N fillers reduced the thermal expansion coefficient to 0.87×10^-5/K,12%of the composites without fillers,and improved the thermal conductivity to 3.885 W·m^-1·K^-1,16.8 times higher than the non-fillers composites.After the comparison of the effects of the fillers sizes and content on the properties of the composites,the author found that the thermal properties of the composites could be adjusted by changing the contents and mixture ratio of the fillers, and the epoxy electronic encapsulating material mixed with 50%ZrW208 and 20% nano-A1N had the most excellent properties(its thermal conductivity is 2.083 W·m^-1·K^-1, thermal expansion coefficient is 1.25x10-5/K,and bending strength is 168.5 MPa).In this material,the thermal conductivity was greatly improved and the thermal expansion coefficient was greatly reduced,while the electrical and mechanical properties were maintained.更多还原