40nm一体化刻蚀工艺技术研究

Research of 40 nm All-in-One Etch Process

用金属硬掩模层(MHM)进行一体化(AIO)刻蚀的工艺是40 nm节点后道工序的关键工艺技术。阐述了40 nm低功耗芯片工艺研发过程中,一体化刻蚀工艺开发所遇到的诸多工艺难题,并对其产生的机理进行了深入分析。结合工艺设备与工艺特性,进行了刻蚀实验并对刻蚀工艺条件进行了优化,使用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对样品形貌进行了观测,采用电迁移测试结构对通孔样品的可靠性进行了测试,结果表明,氮化钛厚度、沟槽剖面形貌和顶部缺口形貌得到优化,双大马士革凹槽形貌、通孔剖面形貌以及通孔底部完整性得到较好控制,解决了氟化钛残留问题,有效解决了一体化刻蚀的工艺难题。

Metal hard mask （MHM） all-in-one （AIO） etch technology is one of key back-end-of-line （BEOL） processes for 40 nm node and beyond. A deep analysis was described that the key issues and solutions during 40 nm MHM AIO etch process development. According to the process machines and features, The morphology of the samples were observed by scanning electron microscopy （SEM） and transinission electron microscopy （TEM）. The redability of the samples was test using the electro-migration structure. The experiment results show that the TiN thickness, the trench profile and the kink profile were optimized, the meanwhile, the chamfer profile, the via profile, the rench bottom roughness issue and the via bottom integri- ty were well controlled by optimizing etch process parameters. The residual of titanium fluoride was also reduced. These indicated that the key issues in MHM AIO etch process were well solved.