Machine learning-based beam shape controlling system on NISSIN medium current ion implanter
摘要
In ion implantation process for semiconductor device fabrication, beam shape is one of important physical quantities that affect device characteristics, specifically dose uniformity and damage control. However, to control it, we must monitor shape accurately, and adjust multiple tuning parameters. This adjustment process is difficult to automate by rule-based programming because implanter requires tuning many parameters. Previously, we had developed beam size controlling system using machine learning model. This model is trained by using equipment parameters and predicts appropriate parameters to tune beam size. However, sometimes beam shape is different even if beam condition is same and the size is OK. To deal with it, we developed beam shape controlling system. We defined such beam shape parameters as “Mura value” and calculated these parameters by image processing. The value becomes indicator of dose uniformity and this system can detect abnormal beam shape and prevent non-uniformity implantation.
Graphical abstractIn ion implantation process for semiconductor device fabrication, beam shape is one of the important physical quantities that affect device characteristics, specifically dose uniformity and damage control. However, to control beam shape, we must monitor beam shape accurately, and adjust multiple beam tuning parameters according to ion implantation conditions. This adjustment process is difficult to automate by rule-based programming. Especially, medium current implanter requires tuning many parameters because the ranges of the energy and the beam current are so wide. Previously, we had developed beam size controlling system using machine learning model. This model is trained by using equipment parameters and predicts parameters to tune beam size. During mass production, if beam condition was same, beam size is almost same. But sometimes beam shape is different. Figure