Method to deposit conformal and low wet etch rate encapsulation layer using pecvd

A method of processing a substrate housed in a process chamber, the method comprising:

• introducing a silicon-containing precursor and a reactant to the process chamber at a substrate temperature less than about 400° C.;
• igniting and pulsing a first plasma while introducing the silicon-containing precursor and the reactant to generate radical species for forming a silicon-containing film over the substrate;
• and
• after forming the silicon-containing film, performing a post-treatment operation, the post-treatment operation comprising:
• stopping flow of the silicon-containing precursor and the flow of the reactant;
• introducing a post-treatment gas into the process chamber;
• and
• igniting a second plasma to treat the silicon-containing film,
• wherein a duration of each pulse during the pulsing of the first plasma is between about 0.02 ms and about 5 ms, and
• wherein the silicon-containing film is silicon nitride and the post-treated silicon-containing film has a wet etch rate in a 100:1 hydrofluoric acid solution of less than about 20 Å/minute.

A method of processing a substrate housed in a process chamber, the method comprising:

• introducing a silicon-containing precursor and a reactant to the process chamber at a substrate temperature less than about 400° C.;
• igniting and pulsing a first plasma while introducing the silicon-containing precursor and the reactant to generate radical species for forming a silicon-containing film over the substrate;
• and
• after forming the silicon-containing film, performing a post-treatment operation, the post-treatment operation comprising:
• stopping flow of the silicon-containing precursor and the flow of the reactant;
• introducing a post-treatment gas into the process chamber;
• and
• igniting a second plasma to treat the silicon-containing film,
• wherein a duration of each pulse during the pulsing of the first plasma is between about 0.02 ms and about 5 ms,
• wherein the first and second plasmas are ignited using a dual frequency plasma generator, and
• wherein the silicon-containing film is silicon nitride, and wherein the density of the silicon nitride is at least about 2.6 g/cm3.