局部高台阶对注入层全局关键尺寸均匀性的影响

Study on the Influence of Local High Steps on the Uniformity of Global Critical Dimension in Implant Layers

在集成电路制造过程中,注入层高台阶分布状态是注入层光刻胶关键尺寸(critical dimension,CD)均匀性质量优劣的重要影响因素之一。通过对高台阶在晶圆上的分布、疏密程度、台阶宽度及与曝光图形距离的研究,探索了影响高台阶注入层光刻工艺CD均匀性的关键参数,提出了一种优化的版图设计方法。实验结果表明:高台阶的均匀分布有利于提高CD的均匀性;台阶疏密程度对CD均匀性的影响较小;台阶宽度越大,CD的平均值越小,但对3σ值没有明显影响;高台阶距离曝光图形越远,CD的均匀性越好。应用优化的版图设计方法后,改善了器件的CD均匀性和生产的稳定性,光刻CD均匀性提高了约49.4%。

In the processes of integrated circuits fabrication,the distribution of high steps in implant layers is one of the critical factors that affects the uniformity and quality of implant-layer photoresist critical dimension(CD).Based on the study of the distribution,density,width and the distance from the exposure patterns to the high steps on the wafer are studied,the key high-step parameters that affect the CD uniformity are found,and an optimized layout-design method is proposed.The experimental results reveal that the CD uniformity is improved with the high steps distributed uniformly.The step density has little effect on the CD uniformity;the larger the step width is,the smaller the average value of CD is,but there is no obvious effect on the value of 3σ;the farther the distance between the high steps and the exposure patterns is,the better CD uniformity is.After applying the optimized layout-design method,the CD uniformity of devices and the stability of production are improved.The CD uniformity of implant layers lithography is increased by 49.4%.