Reactor chamber self-cleaning process

A method of using an RF powered reactor chamber having a gas inlet manifold electrode, and an exhaust outlet system, comprising:

• providing a wafer support electrode for a semiconductor wafer and a gas inlet manifold electrode parallel to the wafer support electrode and having adjustable spacing therebetween;
• as a first process step, depositing at least one layer of silicon-containing material on a wafer positioned on the wafer support electrode;
• as a second process step, spacing apart the gas inlet manifold electrode and the wafer support electrode a first distance and communicating into the chamber via the gas inlet manifold a gas mixture comprising a fluorocarbon gas doped with oxygen while applying RF power between the gas inlet manifold electrode and the wafer support electrode and maintaining the chamber at a first pressure within the range of about 2-15 torr for forming an etching plasma to locally etch deposits from the gas inlet manifold electrode and the wafer support electrode;
• as a third process step, spacing apart the gas inlet manifold electrode and the wafer support electrode a second distance said second distance greater than said first distance and communicating into the chamber via the gas inlet manifold electrode a fluorinated gas while applying RF power between the gas inlet manifold electrode and wafer support electrode and maintaining the chamber at a second pressure, less than the first pressure and selected for forming an etching plasma substantially throughout the chamber.

A method of using an RF powered reactor chamber having a gas inlet manifold electrode, and an exhaust system, comprising:

• providing a wafer support electrode for supporting thereon a workpiece including a semiconductor wafer, a gas inlet manifold electrode parallel to the wafer supporting electrode, the wafer supporting electrode and gas inlet manifold electrode having adjustable spacing therebetween;
• as a first process step, depositing at least one layer of silicon-containing material on a wafer positioned on the wafer supporting electrode;
• as a second process step, spacing apart the gas inlet manifold electrode and the wafer supporting electrode a first distance and communicating into the chamber via the gas inlet manifold electrode a gas mixture comprising a fluorocarbon gas doped with oxygen while applying RF power between the gas inlet manifold electrode and the wafer supporting electrode and maintaining the chamber at a first pressure within the range of about 2-15 torr for forming an etching plasma to locally etch deposits from the gas inlet manifold electrode and the wafer supporting electrode;
• repeating the cycle comprising the first, deposition step and the second, local etch step;
• and
• after at least several said cycles, cleaning the chamber by spacing apart the gas inlet manifold electrode and the wafer supporting electrode a second distance greater than said first distance, communicating into the chamber via the gas inlet manifold electrode a fluorinated gas while applying RF power between the gas inlet manifold electrode and the wafer supporting electrode for forming an etching plasma of the gas and maintaining the chamber at a second pressure lower than the first pressure, said second pressure selected for extending the etching plasma substantially throughout the chamber.

A process for in-situ self-cleaning of the internal chamber components including walls and electrodes of an RF powered reactor chamber, comprising:

• providing a chemical vapor deposition reactor chamber comprising a wafer support adapted for use as an RF electrode and a gas inlet manifold adapted for use as an RF electrode, the gas inlet manifold electrode being adjacent to and oriented parallel to the wafer support electrode, to thereby apply RF power between the gas inlet manifold electrode and the wafer support electrode, the spacing between the gas inlet manifold electrode and the wafer support electrode being variable;
• as a local, gas inlet manifold electrode and wafer support electrode etch step, communicating into the chamber via the gas inlet manifold electrode a gas comprising C.sub.2 F.sub.6 and oxygen while applying RF power between the gas inlet manifold electrode and the wafer support electrode at a density of approximately 1 to 3 watts/cm.sup.2 and while maintaining the chamber at a pressure within the flange of about 2 to 15 torr and the manifold-to-wafer support electrode spacing at a first distance, to thereby etch deposits from at least the gas inlet manifold electrode and the wafer support electrode and adjacent chamber components;
• and
• as an extended area, chamber etch step, communicating into the chamber via the gas inlet manifold electrode NF.sub.3 while applying RF power between the gas inlet manifold electrode and the wafer support electrode at a density of approximately 0.5 to 2 watts/cm.sup.2 and while maintaining the chamber at a pressure within the range of about 0.5 to 1 torr and the manifold-to-wafer support spacing at a second distance greater than the first distance to thereby etch the internal chamber components including the walls thereof.