Induction heated pancake epitaxial reactor

In an inductively heated pancake epitaxial reactor for processing wafers by depositing a film of epitaxial material on the wafers:

• pancake susceptor means for holding the wafers to be processed with their major faces disposed generally in a horizontal plane and for transferring heat to wafers;
• inductive heater means for heating said susceptor means and wafer as held by said susceptor means to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition zone defined within said bell jar means and overlaying the wafers being processed;
• gas distribution means for flowing reactant gases through said bell jar means and said deposition zone along a flow path including a passageway portion generally centrally disposed of said pancake susceptor means;
• said inductive heater means including an electrically conductive coil structure to be driven with radio frequency current for inductively heating said susceptor means;
• purge housing means for enclosing structure within said bell jar means so as to generally partition the atmosphere within said purge housing means from the remaining atmosphere within said bell jar means, said coil structure being disposed within said purge housing means and said purge housing means including a refractory dielectric annular top cover wall portion disposed overlaying the top of said coil structure, a refractory dielectric annular bottom wall portion disposed underlying said coil structure, and refractory dielectric inner and outer axially directed tubular wall portions disposed at the inner and outer peripheries respectively of said annular top cover wall portion and extending below said top cover portion;
• and
• purge gas supply means for feeding a flow of purge gas generally free of film deposition reactant gases into said purge housing means and for elevating the gas pressure within said purge housing means relative to that of said deposition zone for inhibiting the deposition of film materials on said structure within said purge housing means.

In an inductively heated pancake epitaxial reactor for processing wafers by depositing a film of epitaxial material on the wafers;

• pancake susceptor means for holding the wafer to be processed with their major faces disposed generally in a horizontal plane and for transferring heat to wafers;
• inductive heater means for heating said susceptor means and wafers as held by said susceptor means to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition zone defined within with bell jar means and overlaying the wafers being processed;
• gas distribution means for flowing reactant gases through said bell jar means and said deposition zone along a flow path including a passageway portion generally centrally disposed of said pancake susceptor means;
• said inductive heater means including an electrically conductive coil structure to be driven with radio frequency current for inductively heating said susceptor means;
• a member of porous thermally insulative material interposed between said susceptor means and said electrically conductive coil structure for inhibiting the loss of heat by heat transfer from said susceptor to said coil structure;
• purge housing means for enclosing structure within said bell jar means so as to generally partition the atmosphere within said purge housing means from the remaining atmosphere within said bell jar means;
• and
• purge gas supply means for feeding a flow of purge gas generally free of film deposition reactant gases into said purge housing means and for elevating the gas pressure within said purge housing means relative to that of said deposition zone for inhibiting the deposition of film materials on said structure within said purge housing means.

In an inductively heated pancake epitaxial reactor for processing wafers by depositing a film of epitaxial material on the wafers:

• pancake susceptor means for holding the wafers to be processed with major faces thereof disposed generally in a horizontal plane and for transferring heat to the wafer;
• inductive heater means for heating said susceptor means and wafers as held by said susceptor means to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition zone defined within said bell jar means and overlaying the wafers being processed;
• gas distribution means for flowing reactant gases through said bell jar means and said deposition zone along a flow path including a passageway portion generally centrally disposed of said pancake susceptor means;
• said inductive heater means including an electrically conductive coil structure to be driven with radio frequency current for inductively heating said susceptor means;
• a member of porous thermally insulative material interposed between said susceptor means and said electrically conductive coil structure for inhibiting the loss of heat by heat transfer from said susceptor means to said coil structure;
• thermal insulator housing means for housing said member of thermally insulative material and for partitioning the atmosphere within said deposition zone from the atmosphere within said insulator housing;
• and
• purge gas supply means for feeding a flow of purge gas generally free of film deposition reactant gases into said thermal insulative member housing means for elevating the gas pressure within said thermal member housing means relative to that of said deposition zone for inhibiting the deposition of film materials on said member of thermally insulative material within said thermal member housing means.

In an inductively heated pancake epitaxial reactor for processing wafers by depositing a film of epitaxial material on the wafers:

• pancake susceptor means for holding the wafers to be processed with their major faces disposed generally in a horizontal plane and for transferring heat to the wafers;
• inductive heater means for heating said susceptor means and wafers to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition zone defined within said bell jar means and disposed overlaying the wafers being processed;
• gas distribution means for feeding reactant gases into said deposition zone;
• said inductive heater means including an electrically conductive coil structure to be driven with radio frequency current for inductively heating said susceptor means;
• said coil structure including a plurality of electrically conductive tubular conduits stacked vertically, one above the other, to define in each turn of said coil structure a composite electrical conductor of elongated transverse cross sectional area with the transverse axis of elongation being generally in the vertical direction;
• and
• means for flowing fluid coolant through said tubular conduits for cooling of said coil structure.

In an inductively heated pancake epitaxial radio reactor for processing wafers by depositing a film of epitaxial material on the wafers:

• pancake susceptor means for holding the wafers with their major faces to be processed generally in a horizontal plane and for transferring heat to the wafers;
• inductive heater means for heating said susceptor means and wafers as held on said susceptor means to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition zone defined within said bell jar means and overlaying the wafers being processed;
• gas distribution means for feeding reactant gases into said bell jar means and said deposition zone;
• said bell jar means including a generally bell-shaped refractory member having open and closed ends for disposition over said susceptor means and for partitioning the atmosphere of said deposition zone from the atmosphere outside of said bell jar means;
• said bell-shaped refractory member having a generally circular lip portion at its open end;
• said bell jar means including a generally fixed base plate portion;
• sealing flange means coupled to said lip portion of and movable with said bell-shaped member for selectively sealing said bell-shaped member to said base plate in a generally gas-tight manner;
• and
• said sealing flange means including sealing ring means of compressible material for sealing said bell-shaped member and including clamping means for compressing said sealing ring means radially inwardly into gas-tight sealing engagement with the outer periphery of said lip portion of said bell-shaped member and for mechanically coupling said sealing flange means to said bell-shaped member for movement therewith.

In an inductively heated pancake epitaxial reactor for processing wafers by depositing a film of epitaxial material on the wafers:

• pancake susceptor means for holding the wafers with their major faces to be processed generally in a horizontal plane and for transferring heat to the wafers;
• inductive heater means for heating said susceptor means and wafers as held by said susceptor means to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition zone defined within said bell jar means and overlaying the wafers being processed;
• gas distribution means for feeding reactant gases into said bell jar means and said deposition zone;
• said bell jar means including a generally bell-shaped refractory member having open and closed ends for disposition over said susceptor means and for partitioning the atmosphere of said deposition zone from the atmosphere outside of said bell jar means;
• reflector means including a generally bell-shaped thermal radiant energy reflecting structure disposed generally coaxially of and radially outwardly spaced from said bell-shaped refractory member for reflecting thermal radiant energy emanating from said susceptor means and wafers being processed back to said susceptor means and wafers, said reflecting structure additionally being centrally apertured at its top for flow of fluid coolant therethrough;
• a plurality of generally coaxially radially spaced cylindrical vanes disposed in said central aperture of said reflecting structure;
• air cooling means for flowing a stream of cooling air through a cooling annulus defined between said bell-shaped refractor member and said outwardly spaced bell-shaped reflecting structure for cooling of said bell-shaped refractory member to inhibit deposition of unwanted material on the inside surface of said bell-shaped refractory member;
• and
• a plurality of said coaxial vanes having outwardly flared lower flange portions facing into said cooling annulus for partitioning the flow of fluid coolant into a plurality of coaxial flow streams and for reflecting thermal radiant energy emanating from said susceptor means and wafers back to said susceptor means an wafers, thereby inhibiting the loss of thermal energy from the epitaxial reactor out through the central aperture in said thermal energy reflecting structure.

In an inductively heated pancake epitaxial reactor for processing wafers by depositing a film of epitaxial material on the wafers:

• pancake susceptor means for holding the wafers with their major faces to be processed generally in a horizontal plane and for transferring heat to the wafers;
• inductive heater means for heating said susceptor means and wafers as held by said susceptor means to an elevated deposition temperature by radio frequency induction;
• bell jar means for enclosing said susceptor means and the wafers to be processed and for controlling the atmosphere in a deposition one defined within said bell jar means and overlaying the wafers being processed;
• gas distribution means for feeding reactant gases into said bell jar means and said deposition zone;
• said bell jar means including a generally bell-shaped refractory member having open and closed ends for deposition over said susceptor means and for partitioning the atmosphere of said deposition zone from the atmosphere outside of said bell jar means, the closed end of said bell-shaped member being concave and having a maximum radius of curvature in excess of the axial length of said bell-shaped member, whereby the volume of said bell jar means is reduced to facilitate economies in utilization of power and consumption of reactant and purge gases;
• and
• said bell-shaped member having a diameter at its open end greater than its axial length, whereby the volume of said bell jar means is reduced to facilitate economies in utilization of power and consumption of reactant and purge gases.