Prediction of Fluctuations in Plasma–Wall Interactions Using an Equipment Engineering System

Abstract

The fluctuations in etch rates caused by changes in chamber conditions were studied. Excess deposition of C-F polymer on the chamber wall increased CF x density while H was consumed by the polymer and/or was deactivated on the conductive surface of Si electrodes. The change in radical densities had a clear relationship with the SiN etch rate. The etch rate was accurately predicted by statistical analysis using equipment engineering system (EES) data and optical emission spectroscopy (OES) signals which were extracted by considering both the physical model and the results of statistical analysis.

Effects of hydrogen content in films on the etching of LPCVD and PECVD SiN films using CF4/H2 plasma at different substrate temperatures

“…H outflux originated from the film being etched and its surface reaction has been reported to be essential factor for the etching of hydrogenated SiN by fluorocarbon plasmas. [ 21,22,32 ] The H atoms can scavenge the F atoms from the plasma to form HF molecules, which give high polymer deposition rates, especially for Si or SiO 2 etching, because of the fluorine‐poor condition. [ 33–35 ] Nevertheless, for SiN etching, H outflux also reacts with O and N atoms that react with C to form CO, C 2 N 2 , and FCN or HCN byproducts.…”

Mechanism of SiN etching rate fluctuation in atomic layer etching

“…However, when ALE is used for device manufacturing, process stability and suppression of fluctuation, which depend on the chamber conditions, are extremely important. 20,21 Therefore, we investigate SiN ALE stability with process optimization of the surface adsorption and desorption steps, and we clarify the rate fluctuation mechanism.…”

Hydrogen effects in hydrofluorocarbon plasma etching of silicon nitride: Beam study with CF+, CF2+, CHF2+, and CH2F+ ions

“…Etching chemistry by C x H y F þ z ions (with x, y, z being some integers) generated in such plasmas significantly affects etch selectivities among Si 3 N 4 , SiO 2 , and Si. For example, it has been known that hydrogen gas added to a fluorocarbon plasma in reactive ion etching (RIE) processes increases Si 3 N 4 etch rates, 3 which suggests that hydrogen in hydrofluorocarbon plasmas plays a determining role for etching rates of Si 3 N 4 .…”