Saving ion-damaged spacers

A method of reactive-ion etching a conformal layer on a patterned substrate, the method comprising:

• providing a patterned substrate having exposed silicon and exposed silicon oxide, wherein the exposed silicon oxide has vertical sidewalls and is disposed above the exposed silicon;
• forming a conformal layer on the patterned substrate, wherein forming the conformal layer covers the exposed silicon and the exposed silicon oxide, forming vertical and horizontal portions of the conformal layer;
• reactive-ion etching the patterned substrate, wherein reactive-ion etching the patterned substrate reexposes the exposed silicon, reexposes the exposed silicon oxide, and forms vertical spacers on the vertical sidewalls, wherein the vertical sidewalls comprises a damaged spacer portion near the top;
• exposing the patterned substrate to an alkylsilane precursor;
• selectively forming a protective film on the damaged spacer portion;
• forming a native oxide on the exposed silicon by exposing the patterned substrate to atmosphere;
• and
• removing the native oxide.

A method of selectively depositing a protective layer onto a patterned substrate, the method comprising:

• providing a patterned substrate having two neighboring vertical spacers, wherein the two neighboring vertical spacers have damaged spacer portions at the top and undamaged spacer portions at the bottom, and wherein the damaged spacer portions were damaged by an ion flux, and wherein an exposed silicon portion is disposed between the two neighboring vertical spacers;
• selectively forming a self-assembled monolayer on the damaged spacer portions;
• placing the patterned substrate in a substrate processing region;
• flowing a hydrogen-containing precursor and a fluorine-containing precursor into a remote plasma region separated from the substrate processing region by a showerhead;
• forming plasma effluents by forming a remote plasma in the remote plasma region;
• flowing the plasma effluents through the showerhead and into the substrate processing region;
• forming solid residue by reacting the plasma effluents with a native oxide on the exposed silicon portion;
• and
• sublimating the solid residue.