Development of Virtual Metrology Using Plasma Information Variables to Predict Si Etch Profile Processed by SF6/O2/Ar Capacitively Coupled Plasma
2021.06.09 20:26
연도 | 2021 |
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저널명 | Materials |
쪽 | - |
Abstract
In the semiconductor etch process, as the critical dimension (CD) decreases and the difficulty of the process control increases, in-situ and real-time etch profile monitoring becomes important. It leads to the development of virtual metrology (VM) technology, one of the measurement and inspection (MI) technology that predicts the etch profile during the process. Recently, VM to predict the etch depth using plasma information (PI) variables and the etch process data based on the statistical regression method had been developed and demonstrated high performance. In this study, VM using PI variables, named PI-VM, was extended to monitor the etch profile and investigated the role of PI variables and features of PI-VM. PI variables are obtained through analysis on optical emission spectrum data. The features in PI-VM are investigated in terms of plasma physics and etch kinetics. The PI-VM is developed to monitor the etch depth, bowing CD, etch depth times bowing CD (rectangular model), and etch area model (non-rectangular model). PI-VM for etch depth and bowing CD showed high prediction accuracy of R-square value (R2) 0.8 or higher. The rectangular and non-rectangular etch area model PI-VM showed prediction accuracy R2 of 0.78 and 0.49, respectively. The first trial of virtual metrology to monitor the etch profile will contribute to the development of the etch profile control technology.
Keywords: virtual metrology; plasma information; etch profile; real-time etch depth; bowing CD; rectangular etch profile model; etch area; etch plasma; process monitoring technology
Academic Editor: Alenka Vesel
Materials 2021, 14(11), 3005; https://doi.org/10.3390/ma14113005
Received: 31 March 2021 / Revised: 9 May 2021 / Accepted: 17 May 2021 / Published: 1 June 2021
(This article belongs to the Special Issue Etching Kinetics and Mechanisms of Thin Films)