Inductive Coupled Downstream Plasma CD Trim Process Stability Study

CD trim process is incline to run on strip tool because of the low cost and high throughput benefit. However, CD stability is the key challenge. In this article, PR descum process for CD trim was studied on the chamber with substrate temperature <;300 °C. It is found that the CD was sensitive to the chamber condition which impacted by the mix-run and tool idle while normal strip process kept stable ash rate. The mechanism of the impact was studied and verified. The results from this study also provide guidance on how to get the good stability of CD trim process in downstream plasma chamber.