Gas distribution plate electrode for a plasma reactor

For installation at a ceiling location of a plasma reactor for processing a semiconductor wafer and having a vacuum chamber side wall, a wafer support pedestal for supporting said semiconductor wafer in said chamber, an RF power source coupled to said wafer support pedestal and a process gas source:

• a gas distribution plate comprising:
• a front plate in said chamber and a back plate on an external side of said front plate, said gas distribution plate comprising a gas manifold adjacent said back plate, said back and front plates bonded together and forming an assembly comprising:
• (a) an array of holes through said front plate and communicating with said chamber,
• (b) at least one gas flow-controlling orifice through said back plate and communicating between said manifold and at least one of said holes, said orifice having a diameter that determines gas flow rate to the at least one hole;
• (c) an array of pucks at least generally congruent with said array of holes and disposed within respective ones of said holes to define annular gas passages for gas flow through said front plate into said chamber, each of said annular gas passages being non-aligned with said orifice.

A method of fabricating a gas distribution plate for use in processing semiconductor wafers in a plasma reactor, the gas distribution plate comprising silicon carbide and having plural parallel slots communicating above with respective gas flow-controlling orifices and below with respective rows of annular gas injection passages, said method comprising:

• forming parallel slots in one surface of a silicon carbide plate;
• filling said slots with graphite inserts;
• depositing a layer of silicon carbide on said one surface of said silicon carbide plate;
• removing said graphite inserts by heating said plate;
• drilling respective rows of annular openings through the deposited layer of silicon carbide communicating with respective ones of said slots.

A method of fabricating a gas distribution plate for use in processing semiconductor wafers in a plasma reactor, the gas distribution plate comprising silicon carbide and having plural parallel slots communicating above with respective gas flow-controlling orifices and below with respective rows of annular gas injection passages, said method comprising:

• forming parallel slots in one surface of a silicon carbide plate;
• covering said slots with silicon carbide inserts;
• depositing a layer of silicon carbide on said one surface of said silicon carbide plate;
• drilling respective rows of annular openings through the deposited layer of silicon carbide and through said silicon carbide inserts, said annular openings communicating with respective ones of said slots.

A plasma reactor for processing a semiconductor wafer, said reactor comprising:

• a vacuum chamber side wall;
• a wafer support pedestal for supporting said semiconductor wafer in said chamber;
• an RF power source coupled to said wafer support pedestal;
• a process gas source;
• a gas distribution plate at a ceiling location of said chamber, said gas distribution plate comprising:
• a front plate in said chamber and a back plate on an external side of said front plate, said gas distribution plate comprising a gas manifold adjacent said back plate, said back and front plates bonded together and forming an assembly comprising:
• (a) an array of holes through said front plate and communicating with said chamber,
• (b) at least one gas flow-controlling orifice through said back plate and communicating between said manifold and at least one of said holes, said orifice having a diameter that determines gas flow rate to the at least one hole;
• (c) flow diversion elements for transforming gas flow between said front back plates from stream patterns in said back plate to annular flow patterns in said front plate.