A Review of SiO[sub 2] Etching Studies in Inductively Coupled Fluorocarbon Plasmas

Abstract

A comprehensive overview of results from mechanistic studies on plasma-surface interactions in inductively coupled fluorocarbon plasmas, which are currently widely used for the SiO 2 etching process in semiconductor device manufacturing industry, is presented. The plasma-surface interactions that are covered in this overview range from interactions at the plasma reactor wall and coupling window, which affect the plasma gas phase, to interactions at the substrate level, which determine the etching of both blanket surfaces and microscopic features. In particular, the effects of reactor wall temperature and parasitic capacitive coupling on the SiO 2 etching process are addressed. Further, the mechanism of selective SiO 2 to Si and Si 3 N 4 etching on blanket and inclined surfaces is discussed. Finally, it is shown how the SiO 2 etch process in high aspect ratio microstructures differs from the etch process on blanket surfaces.

Inductively coupled plasma etching of ultra-shallow Si3N4 nanostructures using SF6/C4F8 chemistry

“…As coil power applied is only 100 W, one could say that the platen brings power to the plasma and increases the ion flux causing an ''exponential'' etch rates variation. Moreover, it was also reported in SiO 2 etching that in the suppression regime, the etch rates increase faster than the square root of ion energy [20]. Besides, ZEP and Si 3 N 4 etch rates having the same trend curve reinforces the fact that increasing platen power mainly enhances the physical component of the etching mechanisms.…”

Interface structure of photonic multilayers prepared by plasma enhanced chemical vapor deposition

“…If the thickness and roughness of the SiO x layer were constrained to reasonable values, we were unable to get a good fit. It has been reported [8] that SiO x can be etched by a fluorocarbon plasma in which highly energetic ion bombardment occurs. In that work, a transition from fluorocarbon deposition to etching of the SiO x layer was seen to occur at around 75 W of bias power.…”

A new plasma ash method to prevent resist from flowing into contact and via holes

“…that has not been cross-linked, contaminated or hardened). There are several reports on the modification of the top surface of the photoresist due to exposure to ion bombardment during ion implantation [7] or an RIE plasma process [8,9,10]. From the Auger analysis of a wafer processed through etch, ash and a wet clean [ Figure 2], we found that the post resist strip residue contains mainly Si and O, with a small presence of carbon.…”