Year: 2016
Type: article
Abstract: We evaluated the silicon nitride (SiN) etching characteristics of Ar/O 2 /hydrofluorocarbon plasma. Ar/CH 3 F/O 2 plasma achieved a high etching selectivity of SiN to SiO 2 by increasing the oxygen flow rate. We also evaluated the dependence of SiN etching characteristics on SiN film density. A low-density film deposited at a low temperature of 200 °C (by plasma-enhanced CVD, PECVD) showed an 8–20% lower etching rate of SiN than a high-density film deposited at a high temperature of 780 °C (by low-pressure CVD, LPCVD) when we had a low RF bias of 30 W. This PECVD film might move the competitive balance to oxidation from fluorination, reducing the SiN etching rate. However, when we have a high RF bias of more than 50 W, the SiN etching rate is 2–15% higher in the PECVD film than in the LPCVD film. The etching rate of SiN at various densities depends on the balance between oxidation and ion bombardment.
Authors: Hiroto Ohtake, Tomiko Wanifuchi, Masaru Sasaki
Institution: Tokyo Electron (Japan)
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2474096282