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US5064367A Expired / Lapsed US ⏱️ 0.0 years remaining

Conical gas inlet for thermal processing furnace

Assignee: Hewlett Packard Development Co LP
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Filing: 1990-08-06
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Granted: 1991-11-12
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Expires: 2010-08-06
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Abstract

Abstract A tube furnace used for high-temperature processing of semiconductor wafers or the like employs a cone-like shape for the gas inlet or nozzle where the reactant or insert gas enters the furnace tube. This conical nozzle produces a gas flow of faster velocities, following the flow streamlines, and avoids or minimizes recirculating gas cells. The amount of gas used in purging a tube with this configuration is reduced, and the time needed for thorough purging is also reduced. Greater process control, and enhanced process reproducibility, are also possible because of the reduction in overlap of process steps permitted by the faster purging. This feature of faster purging can, in addition, reduce the infiltration of ambient air which occurs during any processing step.

Inventors

  • 👤 Ara Philipossian

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 01:56
CPC Classifications
C; C30; C30B; C30B31/00; C30B31/06; C30B31/16; F; F27; F27B; F27B17/00; F27B17/0016; F27B17/0025

Claims Analysis

Total Claims: 16
Claim 1
Independent Claim 215 words
A thermal processing furnace, comprising: a) a furnace tube having an elongated cylindrical heated chamber open at one end for receiving a cylindrical cantilever tube containing a plurality of axially-aligned, spaced-apart semiconductor wafers to be processed; b) an inlet for introducing reactant and/or inert gasses into the other end of said cylindrical chamber for directing said gasses into an open end of said cantilever tube to flow axially within said cantilever tube by said wafers to the other end of said cantilever tube, said inlet including a substantially cone-shaped portion to provide a smooth transition from the diameter of said inlet to the diameter of said furnace tube to thereby minimize recirculating gas cells adjacent said inlet, wherein said cone-shaped portion has an axial length greater than the diameter of said furnace tube; c) an outlet for removing said gasses from said one end of said cylindrical cantilever tube including a plurality of circumferentially-spaced openings in the cantilever tube and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and a gas inlet surrounding said one end of the cylindrical chamber and having a plurality of inwardly-directed gas jets for providing a gas curtain protecting said one end when said cantilever tube is not within said cylindrical chamber.
Claim 2
Dependent Claim 215 words
A thermal processing furnace, comprising: a) a furnace tube having an elongated cylindrical heated chamber open at one end for receiving a cylindrical cantilever tube containing a plurality of axially-aligned, spaced-apart semiconductor wafers to be processed; b) an inlet for introducing reactant and/or inert gasses into the other end of said cylindrical chamber for directing said gasses into an open end of said cantilever tube to flow axially within said cantilever tube by said wafers to the other end of said cantilever tube, said inlet including a substantially cone-shaped portion to provide a smooth transition from the diameter of said inlet to the diameter of said furnace tube to thereby minimize recirculating gas cells adjacent said inlet, wherein said cone-shaped portion has an axial length greater than the diameter of said furnace tube; c) an outlet for removing said gasses from said one end of said cylindrical cantilever tube including a plurality of circumferentially-spaced openings in the cantilever tube and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and a gas inlet surrounding said one end of the cylindrical chamber and having a plurality of inwardly-directed gas jets for providing a gas curtain protecting said one end when said cantilever tube is not within said cylindrical chamber.
Claim 3
Dependent Claim 26 words
Apparatus according to claim 1 wherein said furnace tube includes a cylindrical furnace quartz tube, and said inlet is an integral part of said furnace tube.
Claim 4
Dependent Claim 30 words
Apparatus according to claim 1 wherein said furnace tube has a cylindrical shape of substantially constant exterior diameter extending from said one end to about the position of said inlet.
Claim 5
Dependent Claim 287 words
A furnace for performing high-temperature processes upon a plurality of semiconductor wafers, comprising: a) a furnace tube having an elongated cylindrical heated chamber open at one end for receiving said plurality of semiconductor wafers; b) cantilever means for supporting said plurality of semiconductor wafers, said cantilever means including a cylindrical tube for enclosing said semiconductor wafers in axial alignment with and spaced apart from one another, said cantilever means including support means at an outer end for axial movement into said chamber for performing said processes and out of said chamber for loading and unloading said semiconductor wafers; c) an inlet for introducing reactant and/or inert gasses into the other end of said cylindrical chamber, said inlet including a substantially cone-shaped portion to provide a smooth transition from the diameter of said inlet to the diameter of said tube furnace to thereby minimize re-circulating gas cells in an area adjacent said other end, wherein said cone-shaped portion has an axial length greater than the diameter of said furnace tube, the gasses flowing from said inlet into an open end of said cylindrical tube to flow within said cylindrical tube along the length thereof by said plurality of wafers to the other end of said cylindrical tube; d) an outlet for removing said gasses from said one end of said cylindrical tube including a plurality of circumferentially-spaced openings in the cylindrical tube and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and a gas inlet surrounding said one end of the cylindrical chamber and having a plurality of inwardly-directed gas jets for providing a gas curtain protecting said one end when said cantilever means is out of said cylindrical chamber.
Claim 6
Dependent Claim 287 words
A furnace for performing high-temperature processes upon a plurality of semiconductor wafers, comprising: a) a furnace tube having an elongated cylindrical heated chamber open at one end for receiving said plurality of semiconductor wafers; b) cantilever means for supporting said plurality of semiconductor wafers, said cantilever means including a cylindrical tube for enclosing said semiconductor wafers in axial alignment with and spaced apart from one another, said cantilever means including support means at an outer end for axial movement into said chamber for performing said processes and out of said chamber for loading and unloading said semiconductor wafers; c) an inlet for introducing reactant and/or inert gasses into the other end of said cylindrical chamber, said inlet including a substantially cone-shaped portion to provide a smooth transition from the diameter of said inlet to the diameter of said tube furnace to thereby minimize re-circulating gas cells in an area adjacent said other end, wherein said cone-shaped portion has an axial length greater than the diameter of said furnace tube, the gasses flowing from said inlet into an open end of said cylindrical tube to flow within said cylindrical tube along the length thereof by said plurality of wafers to the other end of said cylindrical tube; d) an outlet for removing said gasses from said one end of said cylindrical tube including a plurality of circumferentially-spaced openings in the cylindrical tube and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and a gas inlet surrounding said one end of the cylindrical chamber and having a plurality of inwardly-directed gas jets for providing a gas curtain protecting said one end when said cantilever means is out of said cylindrical chamber.
Claim 7
Dependent Claim 25 words
Apparatus according to claim 4 wherein said furnace tube includes a cylindrical quartz tube, and said inlet is an integral part of said furnace tube.
Claim 8
Dependent Claim 38 words
Apparatus according to claim 4 wherein said furnace tube has a cylindrical shape of substantially constant exterior diameter extending from said one end to beyond the position where said inlet joins the interior wall of said furnace tube.
Claim 9
Independent Claim 197 words
A method of operating a thermal processing furnace, comprising the steps of: a) loading a plurality of axially-spaced articles to be processed within a cantilever tube into one end of a horizontal furnace tube; b) introducing reactant and/or inert gasses by an inlet into the other end of said furnace tube to flow by said articles to said one end axially within said cantilever tube, wherein said inlet includes a cone-shaped portion having an axial length greater than the diameter of said furnace tube; c) flowing said gasses from said inlet to said furnace tube through said inlet of gradually increasing diameter to minimize formation of stagnant gas cells adjacent said other end resulting from said step of introducing; d) removing said gasses from said one end of said cantilever tube by a plurality of circumferentially-spaced openings in the cantilever tube and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and providing a gas curtain protecting said one end when said cantilever tube is not within said furnace tube by a gas inlet surrounding said one end of the furnace tube and having a plurality of inwardly-directed gas jets.
Claim 10
Independent Claim 197 words
A method of operating a thermal processing furnace, comprising the steps of: a) loading a plurality of axially-spaced articles to be processed within a cantilever tube into one end of a horizontal furnace tube; b) introducing reactant and/or inert gasses by an inlet into the other end of said furnace tube to flow by said articles to said one end axially within said cantilever tube, wherein said inlet includes a cone-shaped portion having an axial length greater than the diameter of said furnace tube; c) flowing said gasses from said inlet to said furnace tube through said inlet of gradually increasing diameter to minimize formation of stagnant gas cells adjacent said other end resulting from said step of introducing; d) removing said gasses from said one end of said cantilever tube by a plurality of circumferentially-spaced openings in the cantilever tube and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and providing a gas curtain protecting said one end when said cantilever tube is not within said furnace tube by a gas inlet surrounding said one end of the furnace tube and having a plurality of inwardly-directed gas jets.
Claim 11
Dependent Claim 26 words
A method according to claim 7 wherein said furnace tube includes a cylindrical quartz tube, and said inlet is an integral part of said furnace tube.
Claim 12
Dependent Claim 31 words
A method according to claim 7 wherein said furnace tube has a cylindrical shape of substantially constant exterior diameter extending from said one end to about the position of said inlet.
Claim 13
Independent Claim 270 words
A method of operating a cantilever-type tube furnace for performing high-temperature processes upon a plurality of axially-aligned and spaced-apart semiconductor wafers, comprising the steps of: a) loading said plurality of axially-aligned, spaced-apart semiconductor wafers into a tubular cantilever, and supporting said tubular cantilever at an outer end for axial movement into one end of a tube furnace from a loading position spaced from said tube furnace to an operating position within said tube furnace for performing said processes; c) introducing reactant and/or inert gasses by an inlet into the other end of said tube furnace while said cantilever tube is in said operating position, wherein said inlet includes a cone-shaped portion having an axial length greater than the diameter of said tube furnace; d) flowing said gasses from said inlet to said tube furnace through said cone-shaped portion of gradually increasing diameter to minimize formation of stagnant gas cells and eddies adjacent said inlet resulting from said step of introducing, said gasses flowing from said inlet into an open end of said tubular cantilever to flow axially within the tubular cantilever by said wafers to the other end of said tubular cantilever; d) removing said gasses from said one end of said tubular cantilever by a plurality of circumferentially-spaced openings in the tubular cantilever and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and providing a gas curtain protecting said one end when said tubular cantilever is spaced from said tube furnace by a gas inlet surrounding said one end of the tube furnace and having a plurality of inwardly-directed gas jets.
Claim 14
Independent Claim 270 words
A method of operating a cantilever-type tube furnace for performing high-temperature processes upon a plurality of axially-aligned and spaced-apart semiconductor wafers, comprising the steps of: a) loading said plurality of axially-aligned, spaced-apart semiconductor wafers into a tubular cantilever, and supporting said tubular cantilever at an outer end for axial movement into one end of a tube furnace from a loading position spaced from said tube furnace to an operating position within said tube furnace for performing said processes; c) introducing reactant and/or inert gasses by an inlet into the other end of said tube furnace while said cantilever tube is in said operating position, wherein said inlet includes a cone-shaped portion having an axial length greater than the diameter of said tube furnace; d) flowing said gasses from said inlet to said tube furnace through said cone-shaped portion of gradually increasing diameter to minimize formation of stagnant gas cells and eddies adjacent said inlet resulting from said step of introducing, said gasses flowing from said inlet into an open end of said tubular cantilever to flow axially within the tubular cantilever by said wafers to the other end of said tubular cantilever; d) removing said gasses from said one end of said tubular cantilever by a plurality of circumferentially-spaced openings in the tubular cantilever and an exhaust chamber surrounding said openings, the exhaust chamber including a plurality of circumferentially-spaced exhaust ports; and providing a gas curtain protecting said one end when said tubular cantilever is spaced from said tube furnace by a gas inlet surrounding said one end of the tube furnace and having a plurality of inwardly-directed gas jets.
Claim 15
Dependent Claim 26 words
A method according to claim 10 wherein said tube furnace includes a cylindrical quartz tube, and said inlet is an integral part of said tube furnace.
Claim 16
Dependent Claim 31 words
A method according to claim 10 wherein said tube furnace has a cylindrical shape of substantially constant exterior diameter extending from said one end to about the position of said inlet.

References Cited (Backward Citations)

US3338209A Cited
US4449037A Cited
US4348580A Cited
US4650539A Cited
US4732110A Cited
US4543059A Cited
US4645977A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1994-11-11 1995-05-13 1995-11-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1998-11-11 1999-05-13 1999-11-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2002-11-11 2003-05-13 2003-11-12 $7700.00 Window Closed / Lapsed

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