NEAR SURFACE ETCH SELECTIVITY ENHANCEMENT

摘要

A method of selectively dry etching exposed substrate material on patterned heterogeneous structures is described. The method includes a plasma process prior to a remote plasma etch. The plasma process may use a biased plasma to treat an untreated substrate portion in a preferred direction to form a treated substrate portion. Subsequently, a remote plasma is formed using a fluorine-containing precursor to etch the treated substrate portion using the plasma effluents. By implementing biased plasma processes, the normally isotropic etch may be transformed into a directional (anisotropic) etch despite the remote nature of the plasma excitation during the etch process.

主权项

1. A method of etching a patterned substrate the method comprising:
treating the patterned substrate with a local plasma formed from an inert gas, wherein treating the patterned substrate comprises treating an untreated substrate portion to form a treated substrate portion; and wherein the local plasma is formed by applying a local plasma power to excite the local plasma; and etching the treated substrate portion, wherein etching the treated substrate portion comprises flowing plasma effluents into a substrate processing region housing the patterned substrate after treatment, wherein the plasma effluents are formed by flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a remote plasma in the remote plasma region to produce the plasma effluents, wherein forming the remote plasma in the remote plasma region to produce the plasma effluents comprises applying an RF plasma having an RF plasma power to the remote plasma region.