Remotely-excited fluorine and water vapor etch

摘要

A method of etching exposed silicon oxide on patterned heterogeneous structures is described and includes a remote plasma etch formed from a fluorine-containing precursor. Plasma effluents from the remote plasma are flowed into a substrate processing region where the plasma effluents combine with water vapor. The chemical reaction resulting from the combination produces reactants which etch the patterned heterogeneous structures to produce, in embodiments, a thin residual structure exhibiting little deformation. The methods may be used to conformally trim silicon oxide while removing little or no silicon, polysilicon, silicon nitride, titanium or titanium nitride. In an exemplary embodiment, the etch processes described herein have been found to remove mold oxide around a thin cylindrical conducting structure without causing the cylindrical structure to significantly deform.

主权项

1. A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed silicon oxide region, the method comprising:
flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region through pores in a showerhead while forming a remote plasma in the remote plasma region to produce plasma effluents; flowing water vapor into the substrate processing region without first passing the water vapor through the remote plasma region, wherein the substrate processing region is plasma-free; and etching the exposed silicon oxide region by flowing the plasma effluents through the pores in the showerhead into the substrate processing region, wherein the plasma effluents mix and react with the water vapor and the water vapor is only excited by interaction with the plasma effluents.