【作者】 艾常春；

【导师】 袁良杰；

【作者基本信息】 武汉大学 ， 应用化学， 2011， 博士

【摘要】 作为集成电路的核心,硅芯片从其设计到封装都是现代科学技术高度融合的产物。芯片封装与测试是芯片生产的最后一道关键工序,封装材料的品质直接影响到芯片的工作性能。环氧树脂体系封装材料因具有高可靠性、低成本、生产工艺简单等特点已远远超越了金属封装材料和陶瓷封装材料,占据了封装材料的绝大部分市场,并广泛应用于军事、民用电子器件领域。超大规模集成电路的高度集成化和绿色化发展对封装材料提出了更高的要求,主要包括球形二氧化硅填充材料、高性能环氧树脂以及无卤阻燃等方面。本论文围绕环氧树脂封装材料,在球形二氧化硅的制备、选型以及本征阻燃环氧树脂体系的研究方面取得了一定突破,为进一步开发环保型环氧塑封料奠定了坚实的基础。研究成果如下：1.采用工业级原材料,通过紊流循环法大批量合成了球形二氧化硅水合物,经过热处理得到球形二氧化硅,实验结果表明所合成的二氧化硅球形率高达95%以上,纯度达到99.98%,粒度在1-10μ.m(d50)之间可以调控。研究了五种规格的球形二氧化硅对多种环氧树脂复合物体系流动性的影响,发现对于同一种环氧树脂体系,SS2(d50=2.5μm)组分填充的复合物体系的流动性能明显优于其他组分填充的复合物体系。建立了适合五种球形二氧化硅粒度分布特征的级配模型,指出了在模型参数为0.44时可以得到最紧密堆积,通过多元线性回归得到了较合理的实际级配方案,实验证明级配对于提高球形二氧化硅在环氧树脂体系中的填充量是有效的,并将该方案应用于后续实验中。2.设计和建立了与实际相接近的实验室环氧塑封料制备工艺,改进了原料的共混工艺、熔融软化过程、粉碎成饼和固化成型工艺,设计制作了一套适用于环氧塑封料性能测试的模具,进一步完善了环氧塑封料螺旋流动长度、热膨胀系数、阻燃性能和吸湿性测试程序；建立了一套环氧塑封料原材料的质量检测方法,包括树脂的环氧当量、羟基当量、氯离子含量以及二氧化硅填充剂的测试方法。3.通过热分析手段研究了包覆型三苯基膦促进剂EPCAT-TPP对邻甲酚醛环氧树脂与酚醛树脂的固化反应过程的催化作用,并确定该体系的固化条件为150℃前固化2h,180℃后固化6h；确定了在螺旋流动长度为100 cm时邻甲酚醛单组份环氧树脂体系的二氧化硅填充量为62%,该体系固化后的热膨胀系数达到了70.91×10-6K-1,弯曲强度达到了132.56 MPa(30℃)；研究了添加低粘度环氧树脂的邻甲酚醛双组份体系的固化行为,在螺旋流动长度为100 cm时,该系列体系的最佳填充量可达到73%,其中添加联苯环氧树脂的填充体系在固化后性能最佳,其热膨胀系数达到了47.81×10-6K-1,弯曲强度达到了237.05 MPa(30℃),阻燃性能达到了FV-1级别,吸湿性为0.345%。4.制备了新型含氮磷的阻燃剂AEDPH4,获得了其单晶结构并进行了相关表征。用DSC方法表征了添加AEDPH4后邻甲酚醛环氧树脂体系的固化行为特征,发现固化反应温度降低,体系粘度增大,通过实验确定该体系的固化程序为130℃时前固化4h,180℃时后固化4h。制备了含1 wt%AEDPH4阻燃剂的邻甲酚醛E5-1双组份体系的固化成型样条,其热膨胀系数为49.14×10-6K-1,弯曲强度为225.13 MPa(30℃),阻燃级别达到FV-0级,吸湿性为0.398%,结果表明除了阻燃级别有所提高外,弯曲强度、吸湿性和膨胀系数都不如E5-1体系,而且成型加工性能变差。5.采用热分析手段表征了本征阻燃联苯型环氧树脂与新型酚醛固化剂的固化反应特征,进一步证实了包覆型三苯基膦促进剂EPCAT-TPP对该体系固化反应进程的控制作用；通过研究单组份联苯环氧树脂体系螺旋流动长度与球形二氧化硅填充量的关系确定该体系在螺旋流动长度为100 cm时的填充量为76%,该体系固化后热膨胀系数为45×10-6K-1,弯曲强度为139.68 MPa(30℃),阻燃级别达到FV-0级,吸湿性为0.68%；在该体系中添加其他低粘度环氧树脂后,球形二氧化硅的最佳填充量达到了78%；该填充量下的双组份联苯环氧树脂体系固化后,四种体系的热膨胀系数和弯曲性能趋向一致,其中添加双环戊二烯型环氧树脂的N3-1体系性能最佳,热膨胀系数为42.72×10-6K-1,弯曲强度为190.53 MPa(30℃),阻燃级别达到FV-0级,吸湿性为0.47%。更多还原

【Abstract】 As the core of modern integrated circuits, silica chip from its design to package is a high degree integration of multiple disciplines of human knowledge and technology. Chip package and testing is the final and key procedure in chip production process. The quality of packing materials has an vital effect on the performance of the packaged device. For the high reliability, low cost and simple production technology suitable for large scale production, epoxy molding compounds (EMC) have accounted for the majority of materials market so far beyond the metal packaging materials and ceramics packaging materials, and been widely used in many military and civilian electronics field.The rapid development of VLSI made more strict requirements for packaging materials, including spherical silica filler, high performance epoxy resin and halogen-free flame retardant and so on. As for epoxy encapsulation material, this paper has made some breakthroughs in the preparation and grade of spherical silica and the intrinsic flame retardant epoxy resin system, and laid a solid foundation for further development of environmentally friendly epoxy molding compound. The main results are as follows:1. Large scale synthesis of spherical silica hydrate was conducted by using industrial grade raw materials and turbulent flow cycle method. Micron spherical silica were obtained after heat treatment and the quality indexes of products were characterized in detail, the results show that the rate of spherical balls is above 95%, the purity of silica has achieved 99.98%, and the particle size can be adjusted and controlled between 1～10μm (d50). The effect of five kinds of spherical silica on the flowability of several kinds of epoxy resin system was studied, and the results showed that the system filled with SS2 (d50= 2.5μm) component exhibited better flowability than the other kinds of spherical silica in the same epoxy system. Through the establishment of close packing spherical particles model according to the particle size distribution of five kinds of spherical silica, we know that the closest packing can be achieved when the model parameters n=0.44. The reasonable solution was obtained by multiple linear regression of the actual size distribution. Experiments proved that the grading of spherical silica is effective to improve the content of spherical silica filler in the epoxy resin system, and the grade solution has been used in our following experiments.2. A laboratory preparation process of epoxy molding compound was designed and established according to the actual industrial production, and a set of mold was designed for the of testing EMC performance. The blending process of raw material, process of melting & softening and molding process were all improved in our experiments. The testing procedures of the spiral flow length, thermal expansion coefficient, flame retardant and moisture of epoxy molding compound were further improved. A set of quality testing method for the raw materials of epoxy molding compound was established, including the epoxy equivalent, hydroxyl equivalent, chloride content of resin and the testing methods of silica filler.3. The effect of the coated triphenylphosphine accelerator (EPCAT-TPP) on the curing reaction of the o-cresol formaldehyde epoxy resin and phenolic resin was studied by means of thermal analysis and the curing conditions of 150℃2h+180℃6h was determined. When the spiral flow length of o-cresol formaldehyde epoxy resin system is 100 cm, the appropriate filled loading of this system is 62%, the thermal expansion coefficient (CTE) of this cured system was 70.91×10-6 K-1, and the bending strength was 132.56 MPa (30℃). The curing behavior of two-component system made of o-cresol formaldehyde epoxy resin by adding lower viscosity resin was studied. The filler loading could reach 73% when the spiral flow length was 100 cm, The system made from o-cresol formaldehyde epoxy and biphenyl epoxy resin exhibited best performance:the CTE reached 47.81×10-6K-1, bending strength was 237.05 MPa (30℃), flame retardant properties reached the FV-1 level and the moisture absorption was 0.345%.4. The single crystal and powder of a new flame retardant containing nitrogen and phosphorus AEDPH4 are synthesized and characterized. We can find from the DSC figure that the curing temperature is lower and the viscosity increases after adding 1wt% AEDPH4 to the o-cresol formaldehyde epoxy resin system. The new curing process of 130℃4h+180℃4h was determined. The E5-1 system containing 1 wt% AEDPH4 was prepared, the CTE of this cured system was 49.14×10-6 K-1, the bending strength was 225.13 MPa (30℃), the flame retardant grade reached the FV-0 degree and the moisture absorption was 0.398%. The results showed that in addition to the increased levels of flame retardant, the bending strength, water absorption and coefficient of expansion was not as good as E5-1 system, and the processing behavior was getting even worse.5. The characteristics of the curing reaction of the intrinsic flame retardant biphenyl resin system were studied by the method of thermal analysis. The catalyst and control action of the coated triphenylphosphine accelerator EPCAT-TPP on the curing process of the system was further confirmed. When the spiral flow length of this biphenyl system is 100 cm, the appropriate filled loading of this system is 76%. The CTE of this cured system was 45×10-6 K-1, and the bending strength was 139.68 MPa (30℃), the flame retardant properties reached the FV-0 level and the moisture absorption was 0.68%. The filler loading reached 78% when this system modified by other low viscosity epoxy resins, and the CTE and bending strength of the four cured system got the same results. The N3-1 system adding dicyclopentadiene ring epoxy resin got the best performance:the CTE was 42.72×10-6 K-1, the bending strength was 190.53 MPa (30℃), the flame retardant properties reached the FV-0 level and the moisture absorption was 0.47%.更多还原