Plasma Etching of SiO2 Using Heptafluoropropyl Methyl Ether and Perfluoropropyl Vinyl Ether. (17th November 2018)

• Record Type: Journal Article
• Authors: Kim, Jun-Hyun; Park, Jin-Su; Kim, Chang-Koo
• Is Part Of: ECS journal of solid state science and technology. Volume 7:Number 11(2018)
• Page Start: Q218
• Page End: Q221
• Publication Date: 2018-11-17
• Subjects: Etching - Plasma -- hydrofluoroether -- perfluoroalkyl vinyl ether -- Plasma etching; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0361811jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : As alternative to perfluorocompounds, hydrofluoroether and perfluoroalkyl vinyl ether were used for SiO2 etching. SiO2 was etched in heptafluoropropyl methyl ether (HFE-347mcc3)/Ar and perfluoropropyl vinyl ether (PPVE)/Ar plasmas, separately, and their etch characteristics were compared at bias voltages ranging from −400 to −1200 V. The etch rate of SiO2 in a HFE-347mcc3/Ar plasma was approximately 2.5 times higher than that in a PPVE/Ar plasma at a bias voltage of −400 V. However, the difference in the etch rates decreased with increasing bias voltage, reaching nearly zero at a high bias voltage of −1200 V. The change in the etch rate of SiO2 was attributed to not only the amount of F radicals but also the characteristics in the steady-state fluorocarbon films formed on the SiO2 substrate. In the low-bias voltage regime (−400 to −800 V), higher etch rates in a HFE-347mcc3/Ar plasma than those in a PPVE/Ar plasma were obtained because both the thickness and fluorine-to-carbon (F/C) ratio of the steady-state fluorocarbon film controlled the etch rate of SiO2 . On the other hand, the F/C ratio of the steady-state fluorocarbon film, rather than its thickness, limited the etch rate of SiO2 in the high-bias voltage regime (−800 to −1200 V).