變壓藕合電漿多晶矽乾式蝕刻機蝕刻深度的批次控制

Abstract

積體電路的發展一直朝向高密度快速度化及多功能化的方向前進，目前的技術已經進步到超大型積體電路（Very Large Scale Integration VLSI）的範圍。在邁向高密度化的過程中，各種元件的尺寸及最小圖案線寬也都不斷縮小，因此如何精確的圖形轉移就顯的非常重要了。本研究的目的係在研究如何加強變壓耦合電漿多晶矽乾式蝕刻機蝕刻深度的控制，以期大幅改善蝕刻製程的良率。 在作法上，我設計了EWMA(Exponential Weighted Moving Average)及LS(Least Square)控制器來模擬與分析，由於EWMA模擬時會需要有一個目標模型，所以我另外以最小平方法(Least Square Mothed)和最佳化公式建立一個以腔體壓力(mT)，功率(W)，氯氣流量(sccm)為變數，蝕刻深度( )為輸出的模型以供EWMA控制器模擬時使用。 模擬的結果發現，加入EWMA及LS控制器分別改善了4.1%和1.9%，而在驗證的部份，由於經費有限，故僅作EWMA控制器的驗證，但是亦可發現加入EWMA後，改善了2.11%。顯見加入控制器後，對於變壓耦合電漿多晶矽乾式蝕刻機蝕刻深度的確有明顯的改善。

The development of Integrated Circuits (IC) is moving toward higher and higher density. In echoing this trend, the size of all kinds of elements and associated line widths have to be narrowed accordingly. Therefore, how to transfer the pattern onto wafers accurately has been an important issue. This thesis purposed using the run-to-run control method to improve the accuracy of etching depth for the TCP poly silicon etcher. Two control methods have been studied for the control of TCP etchers; one is EWMA (Exponential Weighted Moving Average), the other one is LS (Least Square). In EWMA controller, the control parameter is the etching power, while they were etching power, chamber pressure, and gas (chlorine) flow rate in the LS control. Simulation results indicate that EWMA and LS controller improve the accuracy of etching depth by 4.7% and 1.9%, respectively. Due to limited resources, the experiments were only done with the EWMA controller. The experimental data indicated that the improvement of etching accuracy was 2.11%.