博世扇贝纹对亚微米硅通孔中应力的影响

Effect of Bosch Scallop on Stress in Submicron TSV

硅通孔(TSV)是三维(3D)集成中的关键互连技术。采用博世(Bosch)工艺刻蚀TSV,尤其是亚微米直径的TSV时,侧壁产生的扇贝纹会引起TSV中的应力集中。利用有限元单元生死技术分析亚微米TSV制备过程中的应力变化,并对应力的影响因素进行了分析。研究了TSV节距、扇贝纹高度和宽度、阻挡层材料参数、工艺温度和工作温度等因素对TSV内部应力的影响,并选择了4个主要因素进行正交实验分析。研究结果表明,减小扇贝纹宽度、增大扇贝纹高度、降低工艺温度均能有效缓解扇贝纹附近的应力波动幅度,其中扇贝纹宽度对应力波动的影响最大。通过上述分析,对影响亚微米TSV应力的主要因素进行了排序,从而为TSV制备过程中的参数优化提供了指导。

Through silicon via(TSV)is a key interconnect technology in three-dimensional(3D)integration.When etching TSVs by Bosch process,especially submicron diameter TSVs,scallops on the sidewalls may cause stress concentration in TSVs.The stress variation during the fabrication process of submicron TSVs was analyzed by the element birth and death technique of finite element analysis and the influence factors of stress were analyzed.The effects of factors,such as TSV pitch,scallop height and width,material parameters of barrier layer,process temperature,working temperature,etc.on the in-ternal stresses in TSVs were investigated,and four main factors were selected for orthogonal experiment analysis.The research results show that reducing the width of scallop,increasing the height of scallop and decreasing the process temperature can effectively alleviate the stress fluctuation amplitude near the scallops.Among them,the scallop width has the greatest influence on the stress fluctuation.Through the above analysises,the main factors affecting the stress of submicron TSVs were ranked,which provided guidance for parameter optimization during the TSV fabrication process.