Effects of hydrogen content in films on the etching of LPCVD and PECVD SiN films using CF4/H2 plasma at different substrate temperatures. Issue 11 (4th August 2021)

• Record Type: Journal Article
• Authors: Hsiao, Shih‐Nan; Britun, Nikolay; Nguyen, Thi‐Thuy‐Nga; Tsutsumi, Takayoshi; Ishikawa, Kenji; Sekine, Makoto; Hori, Masaru
• Is Part Of: Plasma processes and polymers. Volume 18:Issue 11(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-04
• Subjects: bonding structure -- CF4/H2 plasma -- low‐temperature etching -- LPCVD SiN films -- PECVD SiN film; Plasma polymerization -- Periodicals; Plasma-enhanced chemical vapor deposition -- Periodicals; Plasma chemistry -- Periodicals
• DOI: 10.1002/ppap.202100078
• Languages: English
• ISSNs: 1612-8850

Abstract

Abstract: The dependences of etching characteristics on substrate temperature ( T s, from –20 to 50°C) of the plasma‐enhanced chemical vapor deposition (PECVD) SiN films (PE‐SiN) and low‐pressure chemical vapor deposition (LPCVD) SiN films (LP‐SiN) with CF4 /H2 plasma were investigated. The Fourier‐transform infrared spectroscopy shows that both film types were N–H bond‐rich films, but in different hydrogen contents (PE‐SiN 22.7 at% and LP‐SiN 3.8 at%) from the Rutherford backscattering spectroscopy analyses. A higher hydrogen content led to a thinner fluorocarbon thickness because of the reaction between hydrogen outflux and C and N to form an HCN byproduct. The etch rates (ER) for the PE‐SiN were higher than that of the LP‐SiN at all T s, due to the different FC thickness and etching mechanisms proposed. The formation of the N−H x layer on PE‐SiN at low temperature caused the decrease in ER. For the LP‐SiN, the weak dependences of T s on surface structure and ER were observed. Abstract : The dependences of etching characteristics on substrate temperature of –20 to 50°C of the PECVD and LPCVD films with CF4 /H2 plasma were investigated. A higher hydrogen content inside the films led to a thinner fluorocarbon thickness because of the reaction between hydrogen outflux and C and N to form an HCN byproduct. The etch rates for the PECVD film were higher than that of LPCVD at all temperatures due to the different FC thickness and etching mechanism proposed.