Selective deposition of silicon nitride films for spacer applications

A processing method comprising:

• positioning a substrate surface in a processing chamber, the substrate surface having at least one feature thereon, the at least one feature having a top, bottom and sidewalls;
• exposing the substrate surface to a deposition environment comprising at least one deposition cycle, the deposition cycle comprising sequential exposure to a silicon precursor and a nitrogen containing reactant to form a silicon nitride film on the top, bottom and sidewalls of the at least one feature;
• and
• exposing the silicon nitride film to a treatment environment to modify the silicon nitride film deposited on the top and bottom of the at least one feature so that the film on the top and bottom have a wet etch rate that is more than 10 times greater than the film on the sidewalls, the treatment environment comprising a plasma having an ion concentration greater than or equal to about 1010/cm3.

A processing method comprising:

• placing a substrate having a substrate surface with a feature into a processing chamber comprising a plurality of process regions, each process region separated from adjacent process regions by a gas curtain, the feature comprising a top, a bottom and a sidewall;
• exposing at least a portion of the substrate surface to a first process condition in a first process region of the processing chamber, the first process condition comprising a silicon precursor;
• laterally moving the substrate surface through a gas curtain to a second process region of the processing chamber;
• exposing the substrate surface to a second process condition in the second process region of the processing chamber, the second process condition comprising a nitrogen precursor;
• laterally moving the substrate surface through a gas curtain to a third process region of the processing chamber;
• exposing the substrate surface to a third process condition in the third process region of the processing chamber, the third process condition comprising a nitrogen reactant to form a silicon nitride film on the top, bottom and sidewalls of the feature;
• repeating exposure to the first process condition, the second process condition and the third process condition to form a silicon nitride film with a predetermined thickness;
• and
• moving the substrate surface to a fourth process region of the processing chamber, the fourth process region comprising a treatment environment comprising a plasma having an ion concentration greater than or equal to about 1010/cm3 that selectively decreases the wet etch rate of the silicon nitride film on the top and bottom of the feature.