制造工艺对超深亚微米铝互连线通孔应力迁移可靠性的影响

【作者】 刘宇；

【导师】 李炳宗； 彭树根；

【作者基本信息】 复旦大学 ， 集成电路工程， 2010， 硕士

【摘要】 芯片的可靠性是集成电路学术界的重要研究课题和芯片制造业的面临的挑战,而应力迁移可靠性问题是其中最重要的课题之一虽然半导体前沿技术已发展到纳米CMOS领域,铜互连已在高性能器件中得到广泛应用,但是铝互连线工艺仍然在当前大量生产的超深亚微米(0.15-0.18微米)集成电路中普遍应用。但是传统的铝互连线技术仍然碰到了各种各样的应力迁移问题,所以研究制造工艺参数和步骤与铝互连应力迁移的关系,有利于深入了解应力迁移现象,并具有实际的工业应用价值,对提高我国微电子制造技术水平具有积极意义。本论文首先分析了应力迁移可靠性失效的原因,根据应力迁移寿命与各种物理参数关系,对0.15微米芯片铝互连进行了应力迁移寿命测试,并分析了通孔电阻分布模型,发现通孔底部界面接触电阻会显著影响通孔电阻值。论文接着仔细分析了0.15微米逻辑工艺中应力迁移可靠性失效的芯片,通过透射电子显微镜观察,界定应力迁移失效的位置,并且应用俄歇能谱深度组份分析,发现阻挡层Ti薄膜与铝金属顶部TiN薄膜界面存在大量含氟和碳元素的聚合物,导致通孔电阻急剧升高,应力迁移可靠性失效。本论文的实验部分详细讨论了通孔制造工艺,尤其是反应离子刻蚀和去胶工艺对通孔刻蚀过程中聚合物生成的影响,优化了通孔反应离子刻蚀工艺,降低O2的浓度和增加Ar的浓度；在氧等离子体去胶工艺中加入H2+N2形成气体,增强了去除聚合物的能力。经过优化工艺加工的芯片,提高了应力迁移可靠性。更多还原

【Abstract】 The reliability of integrated circuits is an important subject for industry and academy, and stress migration (SM) failure is the most important and persistent challenge among them.Although the leading edge of semiconductor technology has been developed to the field of nano-CMOS, copper interconnects in high-performance devices have been widely used, but the aluminum interconnect technology is still used in the current mass production of ultra-deep submicron (0.15-0.18 micron) integrated circuit. But the traditional Al interconnect technology is still encounter a variety of stress migration problems, so the research of manufacturing process parameters and steps related Al interconnect stress migration is conducive to understanding the phenomenon of stress migration, and has practical value for industrial applications.This thesis first analyzes the reasons for stress migration reliability failure, according to the stress migration lifetime relationships with a variety of physical parameters measure the lifetime of SM on the 0.15-micron chip, analyzes resistance distribution model of via, and find the interface contact resistance the bottom of via can significantly affect the via resistance.Define the location of stress migration failure in the failure chip by transmission electron microscopy to, and find the fluorine and carbon between TiN on the Al and Ti as barrier layer by Auger spectroscopy depth component analysis, which leads to a sharp increase in via resistance and stress migration reliability failure.The experimental part of this thesis discuss the RIE and ICP process optimizing the via etching process by reducing the concentration of 02 and increasing the concentration of Ar; process in oxygen plasma to remove polymer by adding H2+N2 gas, enhancing the ability to remove the polymer. improved stress migration reliability.更多还原