JP4435221B2 - Empty baking method for heat treatment equipment - Google Patents

Description

  The present invention relates to a semiconductor manufacturing technology, and more particularly to improvement of a heat insulating tank of a heater unit. For example, an oxidation process is performed on a semiconductor wafer (hereinafter referred to as an IC) in which a semiconductor integrated circuit device (hereinafter referred to as an IC) is manufactured. The present invention relates to a heat treatment apparatus (furnace) that is effective for performing thermal treatment such as diffusion treatment, film formation treatment, annealing treatment, and reflow treatment.

In an IC manufacturing method, a batch-type vertical hot wall heat treatment apparatus (hereinafter referred to as a heat treatment apparatus) is used to perform diffusion treatment on a wafer.
The heat treatment apparatus includes a vertical process tube that forms a processing chamber into which a wafer is loaded, an exhaust pipe that exhausts the inside of the process tube, and a heater unit that is installed outside the process tube and heats the inside of the process tube. A plurality of wafers are carried in a process tube in a state of being vertically aligned and held by a boat from the bottom furnace port, and the inside of the process tube is heated by a heater unit, whereby the wafer is diffused. Is configured to be applied.
In such a heat treatment apparatus, the heater unit has an elongated heater wire laid on the inner periphery of a heat insulating tank formed in a long cylindrical shape covering the entire process tube.
And this type of conventional heat insulation tank is formed by covering a disk-shaped ceiling wall member with a cylindrical side wall member so as to close its upper end opening (see, for example, Patent Document 1).

JP 2002-270529 A

  However, in the heat insulating tank in which the ceiling wall member is covered with the upper end opening of the side wall body, when the temperature of the heater unit is raised to 1300 ° C., the peripheral portion of the ceiling wall member warps upward. Since a gap is formed between the peripheral portion of the ceiling wall member and the upper end opening of the side wall body, there is a problem that heat in the heat insulating tank escapes.

  The objective of this invention is providing the semiconductor manufacturing apparatus which can prevent that the heat | fever in a heat insulation tank escapes.

Typical means for solving the above-described problems are as follows.
(1) a processing tube forming a processing chamber;
A gas introduction pipe for introducing gas into the processing chamber;
An exhaust pipe for discharging the atmosphere of the processing chamber;
A heat insulating tank provided outside the processing tube,
The insulation tank is
A cylindrical side wall member having upper and lower ends opened;
A ceiling wall member placed on the upper end of the side wall member and closing the opening of the upper end; and
The lower end surface of the ceiling wall member is positioned below the upper end surface of the side wall member placed on the side wall member, and the lower end surface is a flat surface.
(2) A heater unit used in a heat treatment apparatus,
The heater unit is
A cylindrical case;
A heat insulating tank installed inside the case;
A heater wire provided on the inner peripheral side of the heat insulation tank,
The insulation tank is
A cylindrical side wall member having upper and lower ends opened;
A ceiling wall member placed on the upper end of the side wall member and closing the opening of the upper end; and
The lower end surface of the ceiling wall member is located below the upper end surface of the side wall member placed on the side wall member, and the lower end surface is a flat surface.
(3) A heat insulation tank used in a heat treatment apparatus,
The insulation tank is
A cylindrical side wall member having upper and lower ends opened;
A ceiling wall member placed on the upper end of the side wall member and closing the opening of the upper end; and
The heat insulation tank, wherein a lower end surface of the ceiling wall member is located below an upper end surface of the side wall member placed on the side wall member, and the lower end surface is a flat surface.
(4) a processing tube forming a processing chamber;
A gas introduction pipe for introducing gas into the processing chamber;
An exhaust pipe for discharging the atmosphere of the processing chamber;
A heat insulating tank provided outside the processing tube;
A heater wire provided on the inner peripheral side of the heat insulation tank,
The insulation tank is
A cylindrical side wall member having upper and lower ends opened;
A ceiling wall member placed on the upper end of the side wall member and closing the opening of the upper end; and
The lower end surface of the ceiling wall member is located below the upper end surface of the side wall member placed on the side wall member, and the semiconductor integration is performed on the substrate to be processed using a heat treatment apparatus in which the lower end surface is a flat surface. A method for manufacturing a semiconductor integrated circuit device for manufacturing a circuit device, comprising:
Carrying the substrate to be processed into the processing chamber;
Heating the substrate to be processed and performing a desired process;
A method for manufacturing a semiconductor integrated circuit device.

  In the heat insulation tank of the above-described means, the side wall member and the ceiling wall member are joined by the step portion, so that even if the ceiling wall member is warped, the peripheral portion of the ceiling wall member and the upper end opening of the side wall member Since it is possible to prevent a gap from being formed between them, it is possible to prevent the heat in the heat insulating tank from escaping.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a heat treatment apparatus (batch type vertical hot wall heat treatment apparatus) according to an embodiment of the present invention is a vertical process tube 2 arranged vertically and supported by a casing 1. It has.
The process tube 2 is made of quartz (SiO ₂ ) and is formed into a cylindrical shape with the upper end closed and the lower end opened. A cylindrical hollow portion of the process tube 2 forms a processing chamber 3 into which a plurality of wafers held in a state aligned in a vertical direction by a boat are loaded, and a lower end opening of the process tube 2 is a wafer as a substrate to be processed. The furnace port 4 for taking in and out is comprised.
Silicon carbide (SiC) is used on the outside of the process tube 2, and a soaking tube 5 formed in a cylindrical shape with the upper end closed and the lower end opened is covered with a concentric circle and supported vertically by the casing 1. Yes.
An exhaust pipe 6 is connected to a part of the process tube 2, and the exhaust pipe 6 is connected to an exhaust device (not shown) so that the processing chamber 3 can be evacuated to a predetermined degree of vacuum. Yes.
A gas introduction pipe 7 is connected to the other part of the side wall of the process tube 2 so as to communicate with the furnace port 4 of the process tube 2, and the gas introduction pipe 7 is connected to a nitrogen gas supply device (not shown). Has been.
A scavenger 8 surrounding the lower end of the process tube 2 is formed so as to communicate with the outer space of the soaking tube 5. The inside of the scavenger 8 is exhausted by an exhaust pipe (not shown). It has become so.

A boat loading / unloading port 9 is opened at a portion of the ceiling wall of the housing 1 facing the lower end opening of the process tube 2, and the boat loading / unloading port 9 is opened and closed by a shutter 10.
A seal cap 17 is brought into contact with the boat loading / unloading port 9 from the lower side in the vertical direction. The seal cap 17 is formed in a disk shape having a diameter larger than that of the boat loading / unloading port 9, and is configured to be lifted and lowered in the vertical direction by an elevator (not shown) installed vertically inside the housing 1. ing.
On the center line of the seal cap 17, a boat 11 for holding a wafer W as a substrate to be processed is vertically supported and supported.

The boat 11 has a pair of upper end plate 12 and lower end plate 13 in the vertical direction, and a plurality of boats vertically standing between the upper end plate 12 and the lower end plate 13 (three in this embodiment) And a plurality of holding grooves 15 are formed in the three holding members 14 so as to be arranged at equal intervals in the longitudinal direction so as to open facing each other.
The boat 11 inserts the peripheral portion of the wafer W between the holding grooves 15 of the three holding members 14 so that the plurality of wafers W are aligned and held in a state where their centers are aligned with each other. It has become.
A heat insulating cap portion 16 is disposed between the boat 11 and the seal cap 17, and the heat insulating cap portion 16 supports the boat 11 in a state where it is lifted from the upper surface of the seal cap 17, thereby lowering the lower end of the boat 11 to the furnace. It is configured to be separated from the position of the mouth 4 by an appropriate distance.

A heater unit 20 for heating the inside of the process tube 2 is arranged concentrically so as to surround the soaking tube 5 outside the soaking tube 5, and is supported by the housing 1 with the scavenger 8 interposed therebetween.
As shown in FIG. 2, the heater unit 20 includes a case 21 made of stainless steel (SUS) and formed in a cylindrical shape with a closed upper end and a lower end opening. The inner diameter of the case 21 is a soaking tube. It is set sufficiently larger than the outer diameter of 5.
Inside the case 21, a heat insulating tank 22 configured to have a heat resistant temperature of 1600 ° C. is installed. The heat insulating tank 22 is covered with a cylindrical side wall member 23 having an inner diameter larger than the outer diameter of the soaking tube 5 and an outer diameter smaller than the inner diameter of the case 21, and an upper end of the side wall member 23. And a disk-shaped ceiling wall member 24 that closes the upper end opening.

The side wall member 23 of the heat insulating tank 22 is constructed by laying an outer blanket 23a and an inner blanket 23b double on the inner peripheral surface of the case 21, and both the outer blanket 23a and the inner blanket 23b are polycrystalline mullite. The fibers are continuously laminated, formed into a blanket shape, and subjected to needle punch processing.
A stepped female step 25 is formed in the upper end opening of the side wall member 23 by setting the inner blanket 23b to be lower than the outer blanket 23a.
The ceiling wall member 24 of the heat insulating tank 22 is constructed by superposing an upper board 24a and a lower board 24b. Both the upper board 24a and the lower board 24b are formed into a disk shape by adding a binder to polycrystalline mullite fibers, and are configured to have a bending strength of 0.32 MPa after heating at the maximum use temperature. Yes.
On the outer periphery of the ceiling wall member 24, a stair-shaped male step portion 26 is formed by setting the outer diameter of the lower board 24b to be smaller than the outer diameter of the upper board 24a. The female stepped portion 25 of the side wall member 23 and the male stepped portion 26 of the ceiling wall member 24 are set to be fitted to each other, and the male stepped portion 26 of the ceiling wall member 24 is the female shape of the side wall member 23. By being fitted into the stepped portion 25, the ceiling wall member 24 is placed so as to seal the upper end opening of the side wall member 23.

  A heater wire 30 is spirally wired and laid on the inner periphery of the side wall member 23 of the heat insulating tank 22. The heater wire 30 is made of an Fe—Cr—Al alloy and is formed into a round bar shape by extrusion, and is wired spirally on the inner peripheral surface of the side wall member 23, and is formed on the inner peripheral surface of the side wall member 23. It is held by an installed mounting bracket (not shown).

The heater unit 20 configured as described above is subjected to an empty baking step before actual operation.
In the empty baking step, as shown in FIG. 2, the boat loading / unloading port 9 is closed by the shutter 10 without loading the boat 11 into the processing chamber 3, and the room temperature to a predetermined high temperature (1200 ° C. to 1300 ° C.). This is a step of removing impurities inside the heater unit 20 by raising the temperature until about 30 hours.

That is, by performing the empty baking step, the outer blanket 23a and the inner blanket 23b constituting the side wall member 23 of the heat insulating tank 22 and the upper or lower board 24a and the lower board 24b of the ceiling wall member 24 are adhered to or adsorbed to the polycrystalline mullite fibers. Impurities such as bonded metal contaminants and binders for bonding polycrystalline mullite fibers are burned out.
In addition, the aluminum oxide film formed on the surface of the heater element wire 30 by the oxidation reaction between aluminum and oxygen (O ₂ ) of the heater element wire 30 is dense and thin by an empty baking step performed at an extremely high temperature. In order to form a film, the heater wire 30 is effectively protected by a dense and thin aluminum oxide film formed on this surface.
Note that when the empty baking step is performed at a low temperature, a thick and rough aluminum oxide film is formed on the surface of the heater wire 30, and this thick and rough aluminum oxide film is easy to peel off. The durability (life) of the wire 30 is reduced.
Incidentally, the impurity gas generated in the empty baking step is exhausted to the outside of the heater unit 20 through the exhaust pipe of the scavenger 8.

  By the way, as shown in FIG. 3A, when the ceiling wall member 24 ′ having no male stepped portion is covered with the upper end surface of the side wall member 23 ′ and the upper end opening is closed. When the temperature of the heater unit is raised to 1300 ° C. in the empty baking step, as shown in FIG. 3 (b), the ceiling wall member 24 ′ warps upward in the peripheral portion, so that the ceiling wall member Since a gap 27 is formed between the peripheral portion of 24 'and the upper end opening of the side wall member 23', there arises a problem that heat in the heat insulating tank escapes. As a result, since the temperature of the empty baking step of the heater unit in the conventional heat treatment apparatus is set to 1200 ° C., metal contamination in the heater unit cannot be sufficiently reduced.

  However, in the heat insulation tank 22 according to the present embodiment, the male stepped portion 26 on the outer periphery of the ceiling wall member 24 is fitted into the female stepped portion 25 of the upper end opening of the side wall member 23, so that FIG. As shown in (c), even if the temperature of the heater unit 20 is raised to 1300 ° C. and the ceiling wall member 24 warps upward in the empty baking step, the peripheral portion and the side wall member of the ceiling wall member 24 are warped upward. Since it is possible to prevent a gap from being formed between the upper end opening 23 and the heat release in the heat insulating tank, it is possible to prevent the problem of heat escaping. As a result, in the heat treatment apparatus according to the present embodiment, metal contamination in the heater unit can be sufficiently reduced by setting the temperature of the empty baking step to 1300 ° C.

  Since the operation in the heat treatment process of the heat treatment apparatus according to the present embodiment that has been subjected to the empty baking step as described above is the same as that of the heat treatment apparatus provided with the conventional heater unit, the heat treatment apparatus according to the present embodiment. Description of the action of the film forming process is omitted.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the shape of the female step portion 25 of the side wall member 23 and the shape of the male step portion 26 of the ceiling wall member 24 is not limited to a stepped shape, and can be formed as shown in FIG.

  In the second embodiment shown in FIG. 4A, a female step portion 25A having an R chamfered portion and a male step portion 26A are fitted.

  In the third embodiment shown in FIG. 4B, a tapered female step 25B and a male step 26B are fitted.

  In the fourth embodiment shown in FIG. 4C, a female step 25C and a male step 26C having three steps are fitted.

  In the fifth embodiment shown in FIG. 4D, a female step part 25D and a male step part 26D having a single step are fitted.

  The heater wire is not limited to be formed in a round bar shape and is laid helically on the inner periphery of the heat insulation tank, but it is also formed into a corrugated flat plate shape by pressing or laser cutting and arranged in parallel in the heat insulation tank in multiple stages. May be laid.

  The heater unit, the heat insulating tank, the case, and the like are not limited to being formed in a cylindrical shape, but may be formed in a rectangular tube shape or a polygonal tube shape.

Further, as shown in FIG. 5, the present invention can also be applied to a heat treatment apparatus including a rapid heating and quenching heater unit 20A.
An intake pipe 31 is connected to the lower end of the heater unit 20 </ b> A so as to communicate with the inside of the heat insulating tank 22, and an exhaust pipe 32 is connected to the upper end of the heater unit 20 </ b> A so as to communicate with the inside of the heat insulating tank 22. . A radiator 33 and a blower 34 are provided in the exhaust pipe 32 in order from the upstream side. A mounting hole 24c for connecting the exhaust pipe 32 is largely opened at the center of the ceiling wall member 24 of the heater unit 20A.
In this heat treatment apparatus, when cooling is performed, a cooling medium such as air is sucked from the intake pipe 31, and the cooling medium is discharged from the space between the inner periphery of the heat insulating tank 22 and the outer periphery of the soaking tube 5 by the exhaust pipe 32. Exhausted. The cooling medium deprived of heat and heated up is cooled by the radiator 33 in the middle of the exhaust pipe 32 and then discharged. Since cooling is not performed when a wafer is processed in the processing chamber 3, the peripheral portion of the ceiling wall member 24 may be warped upward. In the present embodiment, the side wall member 23 and the ceiling are warped. Since the male and female step portions 25 and 26 are formed at the joint portion with the wall member 24, the occurrence of warpage is prevented.

  The present invention is not limited to a batch type vertical hot wall heat treatment apparatus, and can be applied to other semiconductor manufacturing apparatuses in general.

  As described above, according to the present invention, it is possible to prevent the heat in the heat insulating tank from escaping.

The preferred embodiments include the following.
In the semiconductor manufacturing apparatus provided with a heat insulating tank in which the ceiling wall member is covered with the upper end opening of the cylindrical side wall member,
A semiconductor manufacturing apparatus, wherein a stepped portion is formed at a joint portion between the side wall member and the ceiling wall member.

It is front sectional drawing which shows the heat processing apparatus which is one embodiment of this invention. It is front sectional drawing which shows the principal part. It is each sectional drawing of the principal part explaining the state by curvature, (a) shows a comparative example, (b) shows generation | occurrence | production of the clearance gap in the comparative example, (c) shows the case of this Embodiment. ing. It is each sectional drawing which shows the modification of a level | step-difference part, (a) is 2nd embodiment, (b) is 3rd embodiment, (c) is 4th embodiment, (d) is Each of the fifth embodiments is shown. It is front sectional drawing which shows the principal part of the heat processing apparatus which is other embodiment of this invention.

Explanation of symbols

W ... Product wafer (substrate),
DESCRIPTION OF SYMBOLS 1 ... Housing, 2 ... Process tube, 3 ... Processing chamber 4 ... Furnace port, 5 ... Soaking tube, 6 ... Exhaust pipe, 7 ... Gas introduction pipe, 8 ... Scavenger, 9 ... Boat carry-in / out port, 10 ... Shutter ,
DESCRIPTION OF SYMBOLS 11 ... Boat, 12, 13 ... End plate, 14 ... Holding member, 15 ... Holding groove, 16 ... Thermal insulation cap part, 17 ... Seal cap,
DESCRIPTION OF SYMBOLS 20 ... Heater unit, 21 ... Case, 22 ... Heat insulation tank, 23 ... Side wall member, 24 ... Ceiling wall member, 25 ... Female step part, 26 ... Male step part, 27 ... Gap, 30 ... Heater strand,
20A ... Rapid heating / cooling heater unit,
31 ... Intake pipe, 32 ... Exhaust pipe, 33 ... Radiator, 34 ... Blower.

Claims (1)

A process tube forming a processing chamber;
A gas introduction pipe for introducing gas into the processing chamber;
An exhaust pipe for discharging the atmosphere of the processing chamber;
A heat insulating tank provided outside the process tube ;
A heater wire provided on the inner peripheral side of the heat insulating tank;
A boat for aligning and holding a plurality of substrates;
In the method for empty baking of a heat treatment apparatus comprising a shutter that opens and closes the boat loading / unloading port of the process tube ,
Side wall member made of polycrystalline mullite fiber having a female stepped portion at a cylindrical upper end opening having upper and lower ends, and a ceiling wall member made of polycrystalline mullite fiber having a male stepped portion on a disc-shaped outer periphery Forming the heat insulating tank in which the ceiling wall member closes the upper end opening of the side wall member, and forming the male stepped portion into the female stepped portion.
Providing a scavenger for exhausting the inside of the heat insulation tank outside the lower end of the process tube;
Without loading the boat before Symbol treatment chamber, in a state in which the boat carrying port is closed by the shutter, while the thermal insulation vessel is evacuated by the scavenger, to raise the temperature of the processing chamber to 1300 ° C. and bake step,
An empty baking method for a heat treatment apparatus, comprising:

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