Study of SiO₂ Etching Processing with CH₄/SF₆ Plasmas

Abstract

Silicon dioxide (SiO2) layers using photoresist (PR) masks are etched by inductively coupled plasma in CH4/SF6 under various etching conditions. A thin CHxFy polymer layer which exists on the surface of sample during steady‐state etching is observed. The steady‐state CHxFy layer reduces the physical sputtering of ions, resulting in the etching rate of PR decreases significantly. Although the high‐density plasmas can enhance the physical sputtering to some extent and give SiO2 more opportunities to react with fluorine atoms, it is helpful to improve the etching rate of SiO2. By optimizing process conditions, the thickness of the steady‐state CHxFy layer and the density of ions are regulated, and a reasonable selective etching is obtained.

Plasma-engineered sugarcane bagasse: A novel strategy for efficient mercury removal from aqueous solutions

“…The sputtering of groups from the CH x F top layer generates defect points where the reaction of neutral F can promptly erode the whole structure beneath, creating pores in the initially uniform layer. Thus, the observed pores in the treated SB investigated here (micrographs) are attributed to the simultaneous physical (sputtering) and chemical (etching) effect of the SF 6 plasmas as demonstrated in the work (Man et al 2020).…”

“…Moreover, ion bombardment favors the non-homogeneous removal of material. In the work of Man (Man et al 2020), it was demonstrated that etching of SiO 2 coated with an CH x F layer, in SF 6 /CH 4 plasmas, is regulated, amongst others, by ion bombardment. The sputtering of groups from the CH x F top layer generates defect points where the reaction of neutral F can promptly erode the whole structure beneath, creating pores in the initially uniform layer.…”

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“…We believe that this tendency can be attributed to the formation of a steady-state layer on the surface after long-time etching. 43 The average area of a single rod was calculated from SEM images using ImageJ as shown in Fig. 2c.…”