Methods of forming silicon nitride spacers

A method of forming silicon nitride spacers atop a substrate, comprising:

• depositing a silicon nitride layer atop an exposed silicon containing layer and an at least partially formed gate stack disposed atop a substrate;
• modifying a portion of the silicon nitride layer by exposing the silicon nitride layer to a hydrogen or helium containing plasma that is substantially free of fluorine, wherein a depth of the portion of the silicon nitride layer modified by the hydrogen or helium containing plasma is controlled by adjusting at least one of an amount of power coupled to the plasma, a pressure maintained in a process chamber utilized to perform the modification of the silicon nitride layer or a temperature of the substrate;
• and
• removing the modified portion of the silicon nitride layer by exposing the modified portion of the silicon nitride layer to an aqueous solution containing hydrofluoric (HF) acid or phosphoric (H3PO4) acid to form the silicon nitride spacers, wherein the aqueous solution removes the modified portion of the silicon nitride layer selectively to the silicon containing layer.

A computer readable medium having instructions stored thereon that, when executed, cause a method of forming silicon nitride spacers atop a substrate to be performed in a process chamber, the method comprising:

• depositing a silicon nitride layer atop an exposed silicon containing layer and an at least partially formed gate stack disposed atop a substrate;
• modifying a portion of the silicon nitride layer by exposing the silicon nitride layer to a hydrogen or helium containing plasma that is substantially free of fluorine;
• and
• removing the modified portion of the silicon nitride layer by performing a wet cleaning process to form the silicon nitride spacers, wherein the wet cleaning process removes the modified portion of the silicon nitride selectively to the silicon containing layer.