JP2009238810A - Vertical heat treatment device, and heat treating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical heat treatment device can prevent deterioration of a magnetic seal arranged in an outer periphery of an inner shaft by suppressing heat conduction to the inner shaft, in the case where a biaxial structure is employed in order to agitating a gas in a treatment container of the vertical heat treatment device. <P>SOLUTION: This vertical heat treatment device 1 is used for applying a heat treatment to a treatment object 2 stored in a vertical treatment vessel 3. The vertical heat treatment device is provided with: a tubular outer shaft 10 extended in the treatment vessel 3 through a through-hole of a lid 8 arranged at one end of the treatment vessel 3; the inner shaft 11 arranged in the outer shaft 10 concentrically with the outer shaft 10; and drive means 32 and 35 rotating the outer shaft 10 and the inner shaft 11, respectively. The vertical heat treatment device is structured such that one side of the inner shaft 11 and the outer shaft 10 rotates a boat for storing the treatment object 2 therein, and the other side rotates an agitation means arranged in the treatment vessel 3. Magnetic seals 19 and 22 are arranged between the outer periphery of the inner shaft 11 and the inner periphery of the outer shaft 10 and on the outer peripheral surface of the outer shaft 10, respectively, and the inner shaft 11 includes a hollow cylindrical body with an end on the side extended in the treatment vessel 3 closed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vertical heat treatment apparatus and a heat treatment method. More specifically, the present invention relates to a vertical heat treatment apparatus and a heat treatment method for performing heat treatment on an object to be processed such as a semiconductor wafer.

  As a device for performing heat treatment such as oxidation, diffusion, film formation, and annealing on an object to be processed such as a semiconductor wafer, a vertical heat treatment apparatus that accommodates a plurality of objects to be processed in a vertical processing container and collectively processes them. Are known.

  In such a vertical heat treatment apparatus, an object to be processed is accommodated in a heat treatment boat disposed in a processing vessel, a predetermined reaction gas is supplied into the processing vessel hermetically sealed by a lid, and the oxidation is performed. And heat treatment such as film formation. At that time, in order to uniformly heat a plurality of objects to be processed and to form a uniform film in the case of a film forming process, for example, a rotating shaft connected to the heat treatment boat and penetrating the lid body The heat treatment boat is rotated by a driving means such as a motor connected to (see, for example, Patent Document 1).

JP-A-6-204157

Although a certain degree of uniform heat treatment can be performed by rotating the heat treatment boat as in the apparatus described in Patent Document 1, the reaction gas or the atmosphere gas in the treatment container is not convected, so the heating is uniform. There was a limit to sex.
In addition, since the internal gas does not convect, it takes time to replace the gas in the processing container with another gas.

  Therefore, it is conceivable that the rotary shaft for the heat treatment boat is made hollow, an inner shaft concentric with the rotary shaft is disposed therein, and a stirring means such as a fan or a stirring plate is connected to the tip of the inner shaft. . According to this configuration, the stirring means in the processing container can be rotated by driving the inner shaft to rotate, thereby allowing the gas in the processing container to be convected so that the heating is uniform and the gas flow is uniform. In addition, the gas in the container can be replaced quickly.

  However, when a rotary mechanism is provided in the vertical heat treatment apparatus, there is a problem that heat generated by heating the workpiece is transmitted to the rotary shaft and the rotary shaft is heated to a high temperature. Between the outer periphery of the rotating shaft (outer shaft) for the heat treatment boat and the peripheral edge of the through hole of the member through which the outer shaft passes, and between the inner periphery of the outer shaft and the outer periphery of the inner shaft, In order to keep the seal in a sealed state, a magnetic seal is used together with a normal bearing device. However, when the magnetic seal reaches a high temperature of, for example, about 80 ° C., the oil containing the magnetic material evaporates and the sealing function is impaired. There is a problem of being.

  The present invention has been made in view of such circumstances, and suppresses heat conduction to the inner shaft when a biaxial structure is employed to stir the gas in the processing vessel of the vertical heat treatment apparatus. An object of the present invention is to provide a vertical heat treatment apparatus and a heat treatment method capable of preventing deterioration of a magnetic seal disposed on the outer periphery of the inner shaft.

The vertical heat treatment apparatus of the present invention is a vertical heat treatment apparatus that performs heat treatment on an object to be processed contained in a vertical processing container,
A cylindrical outer shaft extending into the processing container through a through-hole of a lid provided at one end of the processing container;
An inner shaft disposed concentrically with the outer shaft in the outer shaft;
Driving means for rotating the outer shaft and the inner shaft, respectively.
One of the inner shaft and the outer shaft is configured to rotate a boat that accommodates the object to be processed, and the other is configured to rotate a stirring means disposed in the processing container,
Magnetic seals are provided between the outer periphery of the inner shaft and the inner periphery of the outer shaft, and on the outer peripheral surface of the outer shaft, and
The inner shaft is characterized by comprising a hollow cylinder whose end on the side extending into the processing container is closed.

  In the vertical heat treatment apparatus of the present invention, the inner shaft for rotating the stirring means arranged in the processing vessel or the boat for storing the object to be processed is made of a hollow cylindrical body, and the side extended in the processing vessel The end is closed. Thereby, the heat transfer area where the heat in the processing container is transmitted to the inner shaft can be reduced, and heat transfer or heat conduction to the inner shaft can be suppressed. As a result, the heat conduction to the magnetic seal disposed between the outer periphery of the inner shaft and the inner periphery of the outer shaft can be suppressed, and the sealing function of the magnetic seal can be prevented from being impaired by a high temperature.

  It is preferable to further include a gas supply means capable of supplying a cooling gas into the inner shaft. In this case, the inner shaft can be cooled by supplying a cooling gas such as dry air or nitrogen gas into the inner shaft, thereby increasing the temperature of the magnetic seal disposed on the outer periphery of the inner shaft. Can be further reliably suppressed.

  The gas supply means includes a gas supply pipe disposed in the inner shaft along the axial direction of the inner shaft, and a gas discharge port of the gas supply pipe extends into the processing container. It is preferable to arrange in the vicinity of the closed end of the inner shaft. In this case, the cooling gas is discharged from a gas discharge port disposed in the vicinity of the closed end of the inner shaft extending into the processing container, so that the cooling gas flows along the inner peripheral surface of the inner shaft. It can be moved to the open end side. As a result, heat transfer between the cooling gas and the inner peripheral surface of the inner shaft can be performed efficiently, and the cooling effect of the inner shaft can be enhanced.

  The heat treatment method of the present invention is a heat treatment method using the vertical heat treatment apparatus, and is characterized in that the boat and the stirring means are simultaneously rotated.

  According to the vertical heat treatment apparatus and the heat treatment method of the present invention, in the case of adopting a biaxial structure for stirring the gas in the processing container of the vertical heat treatment apparatus, the heat conduction to the inner shaft is suppressed and the inner Degradation of the magnetic seal disposed on the outer periphery of the shaft can be prevented.

Hereinafter, embodiments of a vertical heat treatment apparatus and a heat treatment method of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional explanatory view of a vertical heat treatment apparatus 1 according to an embodiment of the present invention, and FIG. 2 is a main part explanatory view of the vertical heat treatment apparatus 1 shown in FIG.

  The vertical heat treatment apparatus 1 accommodates a plurality of disk-shaped semiconductor wafers 2 that are objects to be processed, and has a cylindrical shape that performs heat treatment such as oxidation, diffusion, film formation (CVD, etc.), annealing on the semiconductor wafer 2. A processing container 3 is provided. The processing container 3 is closed at both ends (in FIG. 1, the illustration of the vicinity of the upper end is omitted for the sake of simplicity). In the vicinity of the upper end, the reaction gas and the cleaning gas are contained in the processing container 3. A gas supply pipe (not shown) for supplying gas is connected, and a gas discharge pipe 4 for discharging the gas in the processing container 3 is connected near the lower end.

  A heating element 5 made of a conductor is disposed on the outer periphery of the processing container 3, and a cylindrical outer shell body 7 is disposed on the outer periphery of the heating element 5 via a heat insulating material 6. A current is supplied to the heating element 5 from a power source (not shown), and the processing container 3 is heated by Joule heat generated by the resistance of the conductor.

  The lower end of the processing container 3 is closed by a lid body 8, and a through hole 9 for penetrating an outer shaft and an inner shaft described later is formed in the center of the lid body 8.

  In the present embodiment, a housing 40 is disposed on the outer side surface 8a of the lid 8 (a surface located on the lower side in FIGS. 1 and 2). The housing 40 includes a disk-shaped base portion 41 and a short cylindrical protrusion 42, and the through-hole 9 and the cylindrical protrusion 42 are concentric on the outer surface 8 a of the lid 8. It is arranged to become. A cooling path 43 through which a coolant such as water can flow is formed in the wall constituting the protrusion 42. A coolant such as water is supplied to the cooling path 43 by a pump (not shown), and the housing 40 is cooled.

  The vertical heat treatment apparatus 1 has a biaxial structure, and an outer shaft 10 and an inner shaft 11 are disposed through the through hole 9. The outer shaft 10 and the inner shaft 11 are concentric with the through hole 9. It is arranged to be.

  The outer shaft 10 is made of, for example, a cylindrical member made of stainless steel, and a flange portion 12 protruding outward in the radial direction is formed at an end portion on the side extended in the processing container 3. . In the present embodiment, the lower end portion of the boat rotating cylinder 14 for rotating the boat 13 that can accommodate the plurality of semiconductor wafers 2 in a stacked state is in contact with the flange surface 12a of the flange portion 12. It is fixed. As shown in FIG. 2, a pulley 30 is fixed to the outer peripheral surface of the lower end portion of the outer shaft 10, and a belt 31 is wound around the outer peripheral surface of the pulley 30. The outer shaft 10 is rotationally driven via the belt 31 by driving means such as a motor 32. The rotation speed of the outer shaft 10 can be appropriately selected within a range of about 1 to 10 rpm, for example.

  On the other hand, the inner shaft 11 is made of, for example, a cylindrical member made of stainless steel, and the end portion on the side extended in the processing container 3 is closed by a closing plate 15, and the opposite end The part is open. A rotating shaft 16 a of a fan or stirring plate (stirring means) 16 for stirring the gas in the processing container 3 is fixed to the upper surface of the closing plate 15. A pulley 33 is also fixed on the outer peripheral surface near the lower end of the inner shaft 11, and a belt 34 is wound around the outer peripheral surface of the pulley 33. The inner shaft 11 is rotationally driven via the belt 34 by driving means such as a motor 35. The number of rotations of the inner shaft 11 can also be selected as appropriate within a range of about 100 to 1000 rpm, for example.

  A pair of rolling bearings 17, 18 are disposed at a predetermined distance between the inner periphery 42 a of the protrusion 42 and the outer periphery 10 a of the outer shaft 10, and the upper and lower rolling bearings 17, 18 are disposed. A magnetic seal 19 is disposed between them. Similarly, a pair of rolling bearings 20 and 21 are spaced apart by a predetermined distance between the inner periphery 10b of the outer shaft 10 and the outer periphery 11a of the inner shaft 11. A magnetic seal 22 is disposed between the rolling bearings 20 and 21.

  In the present embodiment, a gas supply pipe 44 is disposed in the hollow inner shaft 11 along the axial direction of the inner shaft 11. The gas discharge port 45 at the tip of the gas supply pipe 44 is disposed in the vicinity of the inner surface of the closing plate 15 of the inner shaft 11, specifically, at a position spaced about 1 cm from the inner surface 15 a of the closing plate 15. The gas supply pipe 44 is supplied with a cooling gas such as dry air or nitrogen from a gas supply source (not shown). The gas supply means is mainly constituted by the gas supply pipe 44, the gas supply source, and the fan for supplying the gas.

  In the present embodiment, since the inner shaft 11 that rotates the fan or the stirring plate 16 disposed in the processing container 3 is made of a hollow cylinder, the heat in the processing container 3 is transmitted to the inner shaft 11. The heat transfer area can be reduced, and heat transfer or heat conduction to the inner shaft 11 can be suppressed. As a result, heat conduction to the magnetic seal 22 disposed between the outer periphery of the inner shaft 11 and the inner periphery of the outer shaft 10 is suppressed, and the sealing function of the magnetic seal 22 is prevented from being impaired by high temperatures. be able to.

  Further, since the protruding portion 42 of the housing 40 is cooled by a coolant such as water, the magnetic seal 19 disposed between the inner periphery 42a of the protruding portion 42 and the outer periphery 10a of the outer shaft 10 is cooled. Can do. Thereby, also about the magnetic seal 19, it can prevent that the sealing function of the said magnetic seal 19 is impaired by high temperature.

  Further, in the present embodiment, the cooling gas is discharged from the gas discharge port 45 disposed in the vicinity of the closed end of the inner shaft 11 extending in the processing container 3, so that the cooling gas is discharged from the inner periphery of the inner shaft 11. It can be moved along the surface to the open end side of the inner shaft 11. As a result, heat transfer between the cooling gas and the inner peripheral surface of the inner shaft 11 can be performed efficiently, and the cooling effect of the inner shaft 11 can be enhanced.

  In this embodiment, the boat is attached to the outer shaft and the fan or the stirring plate is attached to the inner shaft. However, the present invention is not limited to this, and the fan or the stirring plate is attached to the outer shaft and the inner shaft is attached. It is also possible to use a structure in which a boat is attached.

  In the heat treatment method of the present invention, heat treatment is performed on an object to be processed such as a semiconductor wafer by using the above-described vertical heat treatment apparatus. At that time, a boat for storing the object to be processed, and a gas in the processing container Since the agitating means for agitating the materials is simultaneously rotated, the object to be treated can be heated and treated uniformly.

It is a fragmentary sectional view of one embodiment of the vertical heat treatment apparatus of the present invention. It is principal part explanatory drawing of the vertical heat processing apparatus shown by FIG.

Explanation of symbols

1 Vertical heat treatment equipment 2 Semiconductor wafer (object to be processed)
DESCRIPTION OF SYMBOLS 3 Processing container 8 Cover body 9 Through-hole 10 Outer shaft 11 Inner shaft 13 Boat 14 Boat rotation cylinder 16 Fan or stirring plate (stirring means)
17 Rolling bearing 18 Rolling bearing 19 Magnetic seal 20 Rolling bearing 21 Rolling bearing 22 Magnetic seal 32 Motor (drive means)
35 Motor (drive means)
40 Housing 41 Base part 42 Projection part 43 Cooling path 44 Gas supply pipe 45 Gas outlet

Claims (4)

A vertical heat treatment apparatus for performing heat treatment on an object to be processed contained in a vertical processing container,
A cylindrical outer shaft extending into the processing container through a through-hole of a lid provided at one end of the processing container;
An inner shaft disposed concentrically with the outer shaft in the outer shaft;
Driving means for rotating the outer shaft and the inner shaft, respectively.
One of the inner shaft and the outer shaft is configured to rotate a boat that accommodates the object to be processed, and the other is configured to rotate stirring means disposed in the processing container,
Magnetic seals are provided between the outer periphery of the inner shaft and the inner periphery of the outer shaft, and on the outer peripheral surface of the outer shaft, and
The vertical heat treatment apparatus is characterized in that the inner shaft is formed of a hollow cylindrical body whose end portion on the side extending in the processing container is closed.   The vertical heat treatment apparatus according to claim 1, further comprising a gas supply unit capable of supplying a cooling gas into the inner shaft.   The gas supply means includes a gas supply pipe disposed in the inner shaft along the axial direction of the inner shaft, and a gas discharge port of the gas supply pipe extends into the processing container. The vertical heat treatment apparatus according to claim 2, wherein the vertical heat treatment apparatus is disposed in the vicinity of the closed end of the inner shaft.   The heat processing method using the vertical heat processing apparatus in any one of Claims 1-3, Comprising: The said boat and stirring means are rotated simultaneously, The heat processing method characterized by the above-mentioned.

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