Actinometric Investigation of In-Situ Optical Emission Spectroscopy Data in SiO₂Plasma Etch

Abstract

Optical emission spectroscopy (OES) is often used for real-time analysis of the plasma processes. OES has been suggested as a primary plasma process monitoring tool. It has the advantage of non-invasive in-situ monitoring capability but selecting the proper wavelengths for the analysis of OES data generally relies on empirically established methods. In this paper, we propose a practical method for the selection of OES wavelength peaks for the analysis of plasma etch process and this is done by investigating reactants and by-product gas species that reside in the plasma etch chamber. Wavelength selection criteria are based on the standard deviation and correlation coefficients. Moreover, chemical actinometry is employed for the normalization of the selected wavelengths. We also present the importance of chemical actinometry of OES data for quantitative analysis of plasma. Then, the suggested OES peak selection method is employed.. This method is used to find out the reason behind abnormal etching of PR erosion during a series of SiO 2 etch processes using the same recipe. From the experimental verification, we convinced that OES is not only capable for real-time detection of abnormal plasma process but it is also useful for the analysis of suspicious plasma behavior.

PECVD Chamber Cleaning End Point Detection (EPD) Using Optical Emission Spectroscopy Data

“…However, separating reactant and by-product gas species by engineering intuitive can also be beneficial in our case. The deposited material on the chamber was mainly SiON, and the reactant gases are SF 6 and O 2 for breaking silicon covalent bonding by fluorine, and forming volatile products of SiF, O, F, and N. The detected emission peaks during the cleaning process are presented in Fig. 2, and this is in accord with the engineering principle.…”

“…Optical emission spectroscopy (OES) is a reliable, in-situ and non-invasive monitoring method in plasma processing, and it is widely accepted as an end point detection (EPD) and process diagnosis in plasma etch [6][7][8][9]. In this paper, we practiced EPD of the PECVD chamber cleaning process, using OES.…”