JPS63299116A - Heat-treatment unit - Google Patents

Abstract

PURPOSE:To prevent damage to a process tube and deterioration of a seal member by a method wherein a flange is provided on the end of an opening of the process tube where material to be heated is contained, and an airtight member is provided around the flange to maintain the airtightness inside the process tube. CONSTITUTION:An outside tube 10A is provided as a tube containing a material to be heated, and an inside tube 10B is provided in it with a distance. Under each tube 10A, 10B, an upper manifold 16, an outside manifold 18, and an inside manifold 20 are arranged. The inside manifold 20 holds airtightness against the outside manifold 18 with O-ring 58 as a sealing member set between them, and a flange 60 for the inside tube 10B is placed on the upper side of it. A supporting projection 62 is provided on the upper part of the inside manifold 20, surrounding the flange 60 for the inside tube 10B, and an O-ring 66 as a sealing member is provided between the inclined surface 64 of it and the surrounding surface of the flange 60 to maintain airtightness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat treatment apparatus used for heat treatment such as low pressure CVD treatment of semiconductor wafers.

[Conventional technology]

Conventionally, in low-pressure CVD equipment for semiconductor wafers, heat treatment furnaces with a furnace body installed horizontally (horizontal furnaces) are common, but due to demands such as reducing the installation area of processing equipment, vertical type Furnaces have been put into practical use.

Because the semiconductor wafers to be processed are continuously lined up and processed, the length of the furnace body depends on the processing capacity.
For this reason, in a horizontal furnace where the furnace body is installed horizontally, an installation space proportional to the length of the furnace body is required, and space is also required for moving a boat carrying semiconductor wafers in and out of the furnace body. In contrast, in a vertical furnace, the furnace body is installed in the height direction, so the furnace body extends vertically, but the installation area depends on its diameter, compared to a horizontal furnace. This has the advantage of being extremely compact.

In addition, it cannot be overlooked that vertical furnaces can utilize the convection phenomenon in the height direction when supplying processing gas.

[Problem that the invention seeks to solve]

By the way, when the furnace body is installed vertically, the processing tube is naturally installed vertically as well, so it is significantly different from a horizontal furnace in terms of installation, fixing, airtightness, etc.

For example, if a flange is formed at the lower end of the processing tube for support and thermal inclination, and a sealing member such as an O-ring is installed on the lower surface of the flange, the sealing member functions as a fulcrum in the direction of gravity of the processing tube. As a result, the flange may break due to shearing force due to the load of the processing tube, causing an accident.

Furthermore, if a sealing member is installed on the peripheral surface of a processing tube that does not form a flange, the heat of the processing tube acts on the sealing member, so the sealing member deteriorates due to overheating.
This may cause the airtightness to deteriorate.

Therefore, the present invention aims to prevent damage to the processing tube and deterioration of the sealing member.

[Means for Solving the Problems] As shown in FIG. 1, the heat treatment apparatus of the present invention has an opening in a processing tube (outer tube IOA, inner tube I0B) that accommodates an object to be heated (semiconductor wafer 22). A flange (flange 44.60) is provided at the end, and an airtight maintenance member (O-ring 50.66 as a sealing member) is installed around this flange to maintain airtightness inside the processing tube.

[For production]

In this way, the processing tube can be attached to the supporting members (manifold main body 14, outer manifold 18,
Since it can be supported by the inner manifold 20), and airtightness is maintained by installing a sealing member around the flange, damage to the processing tube is prevented, and deterioration of the airtightness maintaining member due to overheating is prevented.

In the heat treatment apparatus of the present invention, the processing tubes include an outer tube IOA and an inner tube I installed inside the outer tube IOA.
The object to be heated is housed in the inner tube IOB, and the processing gas G is introduced into the inner tube IOB from below and from the upper end of the inner tube IOB. Outer chip IOA
By guiding the heat to the outside and discharging it to the outside through a path between the inner tube IOB and the outer tube IOA, it is possible to uniformly form a film on, for example, the semiconductor wafer 22 as the object to be heated.

〔Example〕

FIG. 1 shows an embodiment of the heat treatment apparatus of the present invention.

Inside the furnace body 2, there are a plurality of heater shelves 4A and 4B.

4C are provided at regular intervals in the vertical direction, and each heater shelf 4A to 4C has a plurality of divided heaters 6A, 6B,
6C is installed. Each of the heaters 68 to 6C is a spirally wound heat generating resistance wire that generates heat by electric current, and is installed independently for each of the heaters 1III4A to 4C. Each of the heaters 6A to 6C is installed vertically, so if the heat is generated uniformly, the one above will be overheated due to heat convection, so the heat generation temperature can be set appropriately to achieve uniform temperature distribution and reduce power consumption. We are trying to A cooling water cooling pipe section 8 is provided below the heater shelf 4A, and by circulating cooling water inside the pipe section 8, overheating of the opening of the furnace body 2 is prevented. Inside this furnace body 2, an outer tube IOA is provided as a processing tube for accommodating the object to be heated, and an inner tube IOB is provided with a certain gap therein.
is installed. At the bottom of each tube IOA, IOB is a manifold body 1 fixed to a support frame 12.
4 is installed.

This manifold body 14 includes an upper manifold 16
, an outer manifold 18 and an inner manifold 20 are installed, the outer tube 10A is connected to the outer manifold 18, and the inner tube 10B is connected to the inner manifold 20.
Supported by

A semiconductor wafer 22 as an object to be heated is placed on a boat 24 and accommodated in the inner tube IOB. In that case, the boat 24 is supported on a heat insulating cylinder 30 that is removably fixed to a rotatable turntable 26 installed below the inner tube IOB using fixing means such as a wing nut 28. The turntable 26 is rotated by a motor 31 serving as a rotation driving means, and helps uniformly process the semiconductor wafer 22.

Processing gas G for, for example, CVD processing of the semiconductor wafer 22 is supplied to a plurality of injectors 32 as gas introduction paths installed at regular intervals inside the inner tube IOB through the lower side or inside of the manifold body 14. and into the inner tube IOB. Processing gas G in the inner tube IOB flows from the opening 34 in the ceiling of the inner tube IOB to the outer tube IOA and the inner tube 1.
0B, and is guided to an exhaust hole 38 as an exhaust passage set in the manifold body 14, using the gap 36 as a gas passage. In this case, a vacuum pump is connected to the exhaust hole 38 to draw and exhaust the processing gas G, and also performs evacuation before processing.

By the way, as shown in FIG. 2, in the manifold main body 14, an upper manifold 16 is fixed to the outer circumference of the outer tube IOA.
It forms a water-cooled zone through which cooling water is passed inside. The manifold main body 14 has a cylindrical shape that surrounds the outer tube IOA, and an outer manifold 18 for supporting the outer tube IOA is installed therein with O-rings 40 and 42 interposed therebetween as sealing members.

A support protrusion 46 is installed on the outer manifold 18 so as to surround the flange 44 of the outer tube IOA. It is provided with an inclined surface portion 48 facing to. This inclined surface portion 48 and the flange 4
An O-ring 5 as a sealing member is provided between the circumferential surface of the
0 is installed to maintain airtightness, and between the upper surfaces of the flange 44 and the support protrusion 46, a holding frame 52 that spans both is provided on the flange 44 side with a metal ring made of stainless steel or the like, a fluorine resin plate, etc. An inclusion 54 is installed and is removably fixed with a mounting screw 56. Note that the outer tube IOA is formed thick near the opening, and the flange 44 is formed by extending the thick portion.

Cooling water is circulated inside the outer manifold 18 to provide sufficient cooling.

Further, below the outer manifold 18, an inner manifold 20 for supporting the inner tube IOB is installed. The inner manifold 20 maintains airtightness by interposing an O-ring 58 as a sealing member with respect to the outer manifold 18, and has an inner tube I on the upper surface thereof.
The OB flange 60 is mounted. A support protrusion 62 is also provided at the upper part of this inner manifold 20 so as to surround the flange 60 of the inner tube IOB, and an O-ring 66 as a sealing member is provided between the inclined surface part 64 and the circumferential surface of the flange 60. A holding frame 68 is installed between the upper surfaces of the flange 60 and the support protrusion 62 and spans both, and a metal ring such as stainless steel, a fluorine resin plate, etc. is attached to the flange 60 side. An inclusion 70 is installed and removably fixed with a mounting screw 72. Note that the vicinity of the opening of the inner tube IOB is also formed thick like the outer tube IOA, and the flange 60 is formed by extending the thick portion.

Cooling water is also circulated inside the inner manifold 20,
Sufficient cooling is provided.

A lid 74 is installed below the inner manifold 20 for opening and closing the opening of the inner tube 10B when loading or unloading the semiconductor wafer 22 into the inner tube IOB. 74 has an insertion hole 76 for inserting a temperature detector such as a thermocouple into the inner tube IOB to measure the temperature inside the inner tube IOB.
is provided. In the center of the lid 74, the heat insulating cylinder 30 and the boat 24 installed on it are mounted on a turntable 26.
A rotation shaft 78 is attached for rotation through the
The motor 31 is connected to this rotating shaft 78.

As mentioned above, the processing tube has a double structure with each tube IOA and IOB, and the semiconductor wafer 22 to be processed is loaded and unloaded from below the inner tube IOB, and the processing gas G is Injector 32
The inner tube IOB can be evacuated in the same manner by being introduced from the inner tube IOB, passed through the inside of the inner tube IOB, taken out from the opening 34 to the outer tube IOA side, and pulled out from the exhaust hole 38 to the outside. The semiconductor wafer 22 is rotated arbitrarily by the turntable 26, so that the processing gas G can be rectified, such as uniform film formation, and the characteristics of the semiconductor wafer 22 to be processed can be controlled.

Furthermore, when assembling or replacing each tube IOA and IOB, the inner tube IOB must be removed separately from the outer tube 10A, outer manifold 18, and exhaust system by unfixing the inner manifold 20, as shown in FIG. Can be done. Further, as shown in FIG. 3, after the inner tube IOH is removed, the outer tube IOA is attached to the outer manifold 1
By unfastening the date, it can be removed together with the outer manifold 18. These operations can be performed using the attached elevating device for loading and unloading the semiconductor wafers 22, so that the operations can be facilitated and their efficiency can be improved.

And the assembly can be done in full (reverse order).

That is, due to this structure, the outer tube IOA and the inner tube IOB can be easily replaced, and
The exhaust hole 38 is provided on the manifold body 14 side, and there is no need to disassemble the exhaust hole 38 side.

Since the exhaust system, the outer tube IOA, and the inner tube IOB can be disassembled and assembled independently in this way, it is possible to prevent products from adhering to each tube IOA and 10B, and to suppress the generation of particles. Can be done.

Further, the upper manifold 16, the outer manifold 18, and the inner manifold 20 each function as a water cooling zone and are sufficiently cooled, so that it is possible to prevent products from adhering to them due to heating.

In the embodiment, the case where the furnace body is placed upright has been described, but the present invention can also be applied to a case where the furnace body is installed at an angle.

〔Effect of the invention〕

According to this invention, since the seal member is installed as an airtight member on the circumferential surface of the flange of the processing tube, it is possible to prevent damage to the processing tube due to unnecessary force, and also prevent deterioration of the seal member due to overheating. Stable heat treatment can be achieved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the heat treatment apparatus of the present invention;
Figure 2 is a sectional view showing the manifold part of the processing tube;
FIG. 3 is a sectional view showing the disassembled state of the heat treatment apparatus shown in FIG. 1. 2... Furnace body 10A... Outer tube 10B... Inner tube 14... Manifold body 18... Outer manifold 22... Semiconductor wafer (object to be heated) 20...
Inner manifold 44.60...Flange

Claims (2)

[Claims] (1) A heat treatment apparatus in which a flange is provided at the open end of a processing tube that accommodates an object to be heated, and an airtight maintenance member is installed around the flange to maintain airtightness within the processing tube. (2) The processing tube is composed of an outer tube and an inner tube installed inside the outer tube, and is installed upright or at a certain angle. It is introduced into the tube from below and guided from the upper end of the inner tube to the outer tube.
The heat treatment apparatus according to claim 1, wherein the space between the inner tube and the outer tube is used as a passageway for discharging to the outside.