應用非線性D-EWMA控制器於電漿蝕刻製程控制

Abstract

本論文主要目的為設計一套應用於Inductively Coupled Plasma (ICP)蝕刻製程之先進製程控制器-非線性D-EWMA控制器。本文利用實驗設計法(Design of Experiment， DOE)找出蝕刻SiO2之內部輸入參數(腔體壓力、RF偏壓和CF4流量)與輸出參數(蝕刻率)之關係，建立批次控制之預測模型，然後利用非線性D-EWMA估測器(Non-linear Double Exponentially Weighted Moving Average estimator)更新每批次之控制模型截距項，再透過最小變異控制器(minimum variance controller)來更新製程配方。使機台的輸入變數可以在改變量最小的限制下，即製程的變動最小的情形下，讓輸出變數快速地到達我們所設定的目標值，由本文的模擬以及上線實驗可知非線性D-EWMA控制器可有效的控制ICP蝕刻製程並增加製程能力。

This thesis presents a new run-to-run (R2R) multiple-input-single-out controller, termed Non-linear D-EWMA(double exponentially weighted moving average) controller, for Inductively Coupled Plasma (ICP) Etch process. The relations between input recipes (Pressure, RF bias and CF4 flow) and output variables (Etch rate) are formed by the experimental design method and the process model is built by multiple regression analysis. The non-linear D-EWMA controller can update the process model and obtain the optimal recipes for the next run. Quantified improvements are obtained in simulations and the real etch processes.