Methods and apparatus for producing stable low k FSG film for HDP-CVD

A substrate processing system comprising:

• a housing defining a process chamber;
• a plasma generating system operatively coupled to said process chamber;
• a substrate holder configured to hold a substrate during substrate processing;
• a gas-delivery system configured to introduce gases into said process chamber;
• a pressure-control system for maintaining a selected pressure within said process chamber;
• a controller for controlling said plasma generating system, said gas-delivery system, and said pressure-control system;
• and
• a memory coupled to said controller, said memory comprising a computer-readable medium having a computer-readable program embodied therein for directing operation of said substrate processing system, said computer-readable program including:
• instructions to control said gas-delivery system to provide a gaseous mixture to said process chamber, said gaseous mixture comprising a first gas that contains both fluorine and silicon, and a second gas that contains oxygen, said gaseous mixture being substantially free of silane and having an atomic-oxygen:atomic-silicon ratio of at least 2.0:1;
• instructions to control said plasma generating system to generate a high-density plasma from said gaseous mixture;
• and
• instructions to control said substrate processing system to deposit a fluorinated silicate glass (FSG) layer onto said substrate using said high-density plasma, said FSG layer being substantially free of hydrogen.