HALOGEN-FREE GAS-PHASE SILICON ETCH

摘要

A method of selectively dry etching silicon from patterned heterogeneous structures is described. The method optionally includes a plasma process prior to a remote plasma etch. The plasma process may use a biased plasma to treat some crystalline silicon (e.g. polysilicon or single crystal silicon) to form amorphous silicon. Subsequently, a remote plasma is formed using a hydrogen-containing precursor to form plasma effluents. The plasma effluents are passed into the substrate processing region to etch the amorphous silicon from the patterned substrate. 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 substrate, the method comprising:
treating the substrate with a local plasma formed from an inert gas, wherein treating the substrate comprises transitioning a crystalline silicon portion of the substrate into an amorphous silicon portion of the substrate and wherein the local plasma is formed by applying a local plasma power to excite the local plasma; and etching the amorphous silicon portion of the substrate, wherein etching the amorphous silicon portion of the substrate comprises flowing plasma effluents into a substrate processing region housing the substrate after treating the substrate, wherein the plasma effluents are formed by flowing a hydrogen-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 a remote RF plasma having a remote RF plasma power to the remote plasma region.