Peeling Defect Studying with N2/H2 Plasma during Carbon-based Recess Etch

Abstract

N2/H2 plasmas are often adopted for controllable etching of C-based materials, such as for etching back end of line (BEOL) tri-layer resist. In this paper, N2/H2 chemistry has been used for a spin-on carbon (SOC) recess application in a Lam capacitively coupled plasma (CCP) etch system. Peeling defects are more problematic for this recess etch than the traditional tri-layer carbon etch due to the Si-based byproducts that form readily on SiO2 in N2/H2 plasmas. Here, we report on the important role N2 plays in this process space and describe two methods to mitigate the peeling defect mode for this application.