Methods for protecting device components from chemical mechanical polish

Abstract

A method for preventing CMP-induced (chemical-mechanical polish) damage to a substrate disposed below a pad nitride layer of a mesa. The pad nitride layer is disposed below a conformally deposited dielectric layer. The dielectric layer is disposed below a conformally deposited polysilicon layer. The method includes planarizing the polysilicon layer down to at least a surface of the dielectric layer using the CMP to expose a first region of the dielectric layer. The method further includes etching partially through the first region of the dielectric layer using first etch parameters. The first etch parameters include an etchant source gas that is substantially selective to the pad nitride layer to prevent the pad nitride layer from being etched through even in the presence of a CMP defect. Additionally, there is also included removing the polysilicon layer after the etching partially through the first region of the dielectric layer.