Rotating susceptor semiconductor wafer processing cluster tool module useful for tungsten CVD

A chemical vapor deposition (CVD) reactor apparatus for coating semiconductor wafers with a tungsten film deposited in a temperature controlled CVD reaction comprising:

• a sealed cold wall reactor vessel enclosing an interior volume, the vessel having exhaust means for maintaining the volume at a vacuum pressure level;
• a susceptor supported in a processing space in the internal volume of the vessel for rotation about a vertical axis and a horizontal wafer supporting surface thereon;
• a gas mixing chamber disposed in the volume having connected thereto cooling means for maintaining gases in the distribution chamber at a sub-reaction temperature;
• supplying means including a source of tungsten hexafluoride reactant gas, a source of reducing reactant gas, means for supplying the tungsten hexafluoride reactant gas to the mixing chamber, and means for supplying reducing reactant gas to the mixing chamber;
• showerhead means horizontally disposed parallel to the wafer supporting surface and generally centered on the axis and spaced from the wafer supporting surface for directing a flow of reactant gas at sub-reaction temperature from the mixing chamber into the processing space parallel to the axis, toward and perpendicular to the wafer supporting surface of the susceptor;
• means carried by the susceptor for holding the wafer centered on the supporting surface for processing with a surface of the wafer facing the showerhead means;
• means for heating the wafer held to the supporting surface to a controlled reaction temperature effective to make the reactant gases react and deposit a tungsten film on the wafer;
• and
• drive means for rotating the susceptor on the axis, and thereby rotating a wafer held thereto on its center, to a rotational speed at which a boundary layer is produced adjacent the surface of the wafer and the mixed gases flow radially outwardly from a stagnation point on the axis at the center of the wafer, the rotational speed of the drive means being sufficiently high to make the reactant gas boundary layer immediately adjacent the surface of the wafer sufficiently thin to facilitate the flow of mixed reactant gases through the boundary layer to the surface of the wafer and the removal of products from a tungsten hexafluoride reduction reaction caused by the heated wafer escaping through the boundary layer from the surface of the wafer.

A processing apparatus for processing semiconductor wafers comprising:

• a sealed vessel enclosing an interior volume, the vessel having exhaust means for maintaining the volume at a vacuum pressure level;
• a susceptor supported in a processing space in the interior volume of the vessel for rotation about an axis, the susceptor having a wafer supporting surface thereon oriented perpendicular to the axis;
• a gas distribution chamber disposed in the volume;
• means for supplying at least one process gas to the distribution chamber;
• showerhead means in communication with the distribution chamber disposed parallel to the wafer supporting surface and generally centered on the axis and spaced from the wafer supporting surface for directing a flow of process gas at a sub-processing temperature from the distribution chamber into the processing space parallel to the axis, toward and perpendicular to the wafer supporting surface of the susceptor;
• means carried by the susceptor for holding the wafer to the supporting surface centered on the axis for processing with a surface of the wafer facing the showerhead means;
• means for maintaining the temperature of a wafer held on the supporting surface at a processing temperature;
• and
• drive means for rotating the susceptor on the axis, and thereby rotating a wafer held thereto on its center, to a rotational speed at which a boundary layer is produced adjacent the surface of the wafer and so that the process gas flows radially outwardly from a stagnation point on the axis at the center of the wafer, the rotational speed being sufficiently high to make the boundary layer immediately adjacent the surface the removal of the wafer sufficiently thin to facilitate (1) the flow of process gas through the boundary layer to the surface of the wafer and (2) of process products from the surface of the wafer;
• the showerhead means having gas passage means distributed thereover such that the mass flow rate of process gas flowing radially outward on the susceptor surface, when rotating at the rotational speed, is matched, at various radii on the wafer surface, by a mass flow rate of process gas flowing parallel to the axis from the showerhead toward and against the susceptor surface, so as to maintain the radially flowing process gas distribution uniform over the surface of the wafer.

A chemical vapor deposition (CVD) reactor apparatus for coating semiconductor wafers with a film deposited in a temperature controlled CVD reaction comprising:

• a sealed cold wall reactor vessel enclosing an interior volume, the vessel having a gas exhaust port connectable to a vacuum pressure level;
• a susceptor supported in a processing space in the interior volume of the vessel for rotation about an axis, the susceptor having a wafer supporting surface centered on the axis and oriented perpendicular to the axis;
• a gas distribution chamber disposed in the volume having cooled surfaces therein effective to maintain gases therein at a sub-reaction temperature;
• supply lines connected to the gas distribution chamber and connectable to a source of at least one reactant gas containing a component of a coating substance;
• a showerhead disposed parallel to the wafer supporting surface and generally centered on the axis and spaced from the wafer supporting surface having gas outlets directed from the distribution chamber into the processing space parallel to the axis, toward and perpendicular to the wafer supporting surface of the susceptor;
• a wafer holder on the susceptor centered on the supporting surface so as to hold a wafer centered on the axis with a surface of the wafer facing the showerhead;
• a wafer heater effective to heat a wafer held on the supporting surface to a reaction temperature of a controlled CVD reaction that deposits the coating substance as a film on the substrate;
• and
• a rotary drive operable to rotate the susceptor on the axis, to thereby rotate a wafer held thereto on its center, to a rotational speed at which a boundary layer is produced adjacent the surface of the wafer and the reactant gas flows radially outwardly from a stagnation point on the axis at the center of the wafer, the rotational speed being sufficiently high to make the reactant gas boundary layer immediately adjacent the surface of the wafer sufficiently thin (1) to facilitate the flow through the boundary layer of reactant gas in reaching the surface of the wafer and (2) to facilitate the flow of non-deposition byproducts of the CVD reaction from the surface of the wafer.

A chemical vapor deposition (CVD) reactor apparatus for coating semiconductor wafers with a tungsten film deposited in a temperature controlled CVD reaction comprising:

• a sealed cold wall reactor vessel enclosing an interior volume, the vessel having an exhaust connecting the volume to a vacuum pressure level;
• a susceptor supported in a processing space in the internal volume of the vessel for rotation about a vertical axis and a horizontal wafer supporting surface thereon;
• a gas mixing chamber disposed in the volume having connected thereto cooling elements operative to maintain gases in the distribution chamber at a sub-reaction temperature;
• supplying lines suitable for conducting tungsten hexafluoride reactant gas and reducing reactant gas from respective sources to the mixing chamber;
• a showerhead horizontally disposed parallel to the wafer supporting surface and generally centered on the axis and spaced from the wafer supporting surface and oriented to direct a flow of the mixed gas at sub-reaction temperature from the mixing chamber into the processing space parallel to the axis, toward and perpendicular to the wafer supporting surface of the susceptor;
• a wafer holder on the susceptor positioned to hold the wafer centered on the supporting surface with a surface of the wafer facing the showerhead;
• a wafer heater proximate the supporting surface operative to heat a wafer thereon to a controlled reaction temperature effective to make the mixed gases react to deposit a tungsten film on the wafer;
• and
• a rotary drive operative to rotate the susceptor on the axis and a wafer held thereto on its center, to a rotational speed at which a boundary layer is produced adjacent the surface of the wafer and the mixed gases flow radially outwardly from a stagnation point on the axis at the center of the wafer, the rotational speed of the drive being sufficiently high to make the reactant gas boundary layer immediately adjacent the surface of the wafer sufficiently thin to facilitate the flow of mixed reactant gases through the boundary layer to the surface of the wafer and removal of products from a tungsten hexafluoride reduction reaction caused by the heated wafer escaping through the boundary layer from the surface of the wafer.

A processing apparatus for processing semiconductor wafers comprising:

• a sealed vessel enclosing an interior volume, the vessel having an exhaust port connectable to a vacuum pressure level;
• a susceptor supported in a processing space in the interior volume of the vessel for rotation about an axis, the susceptor having a wafer supporting surface thereon oriented perpendicular to the axis;
• a gas distribution chamber disposed in the volume;
• supply lines connected to the distribution chamber and connectable to sources of at least one process gas;
• a showerhead in communication with the distribution chamber disposed parallel to the wafer supporting surface and generally centered on the axis and spaced from the wafer supporting surface for directing a flow of process gas at a sub-processing temperature from the distribution chamber into the processing space parallel to the axis, toward and perpendicular to the wafer supporting surface of the susceptor;
• a wafer holder on the susceptor to hold the wafer to the supporting surface centered on the axis with a surface of the wafer facing the showerhead;
• a wafer heater positioned to heat a wafer held on the supporting surface at a processing temperature;
• and
• a rotary drive operable to rotate the susceptor on the axis, and thereby rotate a wafer held thereto on its center, to a rotational speed at which a boundary layer is produced adjacent the surface of the wafer and so that the process gas flows radially outwardly from a stagnation point on the axis at the center of the wafer, the rotational speed being sufficiently high to make the boundary layer immediately adjacent the surface of the wafer sufficiently thin to facilitate (1) the flow of process gas through the boundary layer to the surface of the wafer and (2) of process products from the surface of the wafer;
• the showerhead having gas passages distributed so that the mass flow of process gas in a radially outward direction on the susceptor surface, when rotating at the rotational speed, is replenished, at various radii on the wafer surface, by the mass flow of process gas flowing parallel to the axis from the showerhead toward and against the susceptor surface, so that radially flowing process gas is maintained in a uniform distribution over the surface of the wafer.