干擾觀測器架構應用在半導體製造批次控制

Abstract

本論文主要目的是提出應用干擾觀測器(Output Disturbance Observer，ODOB)架構設計一套批次(Run-to-Run)控制器。近年來，批次控制在半導體製造的應用相當地廣泛並實現在許多製程上，如蝕刻、微影、化學機械研磨等製程。在這些批次控制器中，EWMA 控制器，Double EWMA控制器和PCC控制器被半導體工業廣為採用。而EWMA控制器，Double EWMA控制器，PCC控制器和ODOB控制器調整參數之間的關係將在本文中分析與討論。只要滿足這些關係，這些控制器將有相同的效能。通常半導體製程的輸入-輸出模型大多假設為一線性靜態的模型。但是，製程的實驗數據經常不夠充足來建立製程的模型，所以在製程上，模型誤差是一直存在的問題。而量測延遲在半導體製程上亦是無法避免的。然而，模型誤差和量測延遲將影響ODOB控制器的穩定度和效能。本文即設計一套強健的批次控制器並分析ODOB控制器的穩定條件，同時考慮量測延遲的問題。為了滿足批次控制的需求，我們提供調整控制器參數的方法來補償製程所產生的干擾，包括偏移、漂移現象，以及製程可能會發生的模型誤差並處理量測延遲的問題。

The purpose of this thesis aims to present the design of the Run-to-Run (RtR) controller by using the Output Disturbance Observer (ODOB) structure. In recent years, RtR control has been widely used and realized in semiconductor manufacturing, such as etch, photolithography and CMP processes. Among the RtR controllers, the EWMA controller, the Double EWMA and the PCC controller are widely adopted in the semiconductor industry. The relations of the tuning parameters among the EWMA controller, the Double EWMA controller, the PCC controller and the Output Disturbance Observer (ODOB) controller are discussed in this thesis. These controllers have the same performance if the tuning parameters satisfy the relations. The process input-output model is usually assumed as a linear static model. But the experimental data in the process are not often sufficient enough to establish the process model, so the model mismatch will always exist in the process. Furthermore, the metrology delay can not be avoided in semiconductor manufacturing. The stability and performance of the ODOB controller are influenced by the model mismatch and metrology delay. In this thesis, one designs a robust ODOB controller and analyzes the robust stable conditions for the ODOB controller and simultaneously considers the metrology delay. To meet the requirements of the RtR control, one also provides the method to tune the optimal parameters to compensate for process disturbances, including the shifts, drifts, and model errors.