JPH0897196A - Heat treatment furnace equipment - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to prevent water in the trap of the vertical atmospheric diffusion furnace from becoming empty, and to always maintain the atmospheric pressure in the diffusion furnace without pressure fluctuation. [Structure] The vertical atmospheric diffusion furnace apparatus 1 is provided with an emptying prevention device for preventing water in a trap 60 provided in a drainage pipe 54A constituting the drainage line from becoming empty. As an example thereof, the empty prevention device 70B of FIG. 3 is composed of an electromagnetic on-off valve 75, which is provided in the drainage pipe 54A immediately before the trap 60, and is operated during the heat treatment of wet oxidation in the vertical atmospheric diffusion furnace. The opening / closing valve 75 is opened and the on-off valve 75 is controlled to be closed during the heat treatment other than the wet oxidation so that the hot air generated by the heat treatment other than the wet oxidation is prevented from entering the trap 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment furnace apparatus for forming an insulating film or the like on the surface of a semiconductor wafer or diffusing impurities, and more particularly to a heat treatment furnace apparatus capable of performing wet oxidation.

[0002]

2. Description of the Related Art In the following description, a vertical atmospheric diffusion furnace apparatus having a wet oxidation function and a diffusion function will be described as an example of a heat treatment furnace apparatus. First, a conventional heat treatment furnace apparatus will be described with reference to FIGS. 9 to 12. FIG. 9 is a conceptual view showing the back surface of the main part of the batch type vertical atmospheric pressure diffusion furnace device, and FIG. 10 is a perspective view of the diffusion furnace which is the heart of the vertical atmospheric pressure diffusion furnace device shown in FIG. 11 is a schematic diagram showing a reaction gas supply system to the diffusion furnace and an exhaust system of the reacted gas from the diffusion furnace of the vertical atmospheric diffusion furnace apparatus, and FIG. 12 is a vertical view of FIG. It is the schematic diagram which expanded and showed the structure of the trap in the type atmospheric pressure diffusion furnace apparatus.

First, an outline of the configuration of the existing batch type vertical atmospheric diffusion furnace apparatus 1 will be described with reference to FIG. In this vertical atmospheric diffusion furnace apparatus 1, the casing 2 is divided into upper and lower two-stage chambers 3 and 4, and the upper chamber 3 is formed of a substantially cylindrical space. A heater 5, a thermocouple 6 for detecting overheat, a thermocouple 7 for temperature control, and a quartz tube 20 shown in FIG. 10, which are not shown in FIG. 9, are installed on the inner peripheral surface of the room 3. ing. That is, the heater 5, the temperature detecting thermocouple 6, and the temperature controlling thermocouple 7 are present between the inner peripheral surface of the chamber 3 and the tube 20, and the entire chamber 3 is called a diffusion furnace.

The lower chamber 4 is a chamber for loading and unloading a certain batch of semiconductor wafers S, and the semiconductor wafers S are stacked and accommodated in the descending quartz boat 8 in a horizontal state at equal intervals (FIG. 10). Further, after the semiconductor wafer S is formed with a film, it is taken out from the quartz boat 8 in this descending state.

Further, as described above, the quartz boat 8 is constructed so that it can be raised from the lower chamber 4 to the upper chamber 3 by an elevator device (not shown), and vice versa. Quartz boat 8 containing S
To the upper chamber 3, and each semiconductor wafer S is heated by the heater 5 in that state, and impurities are diffused on the surface of each semiconductor wafer S based on the chemical reaction of the reaction gas supplied to the upper chamber 3. Alternatively, the surface of the semiconductor wafer S is oxidized by supplying hydrogen gas, oxygen gas, nitrogen gas or the like. Code 9
Is a gas introduction port of the reaction gas existing between the upper and lower chambers 3 and 4, and reference numeral 10 is an exhaust port of the gas after the reaction.

As shown in the enlarged view of FIG. 10, the tube 20 is composed of a transparent outer tube 21 made of quartz and an inner tube 25 also made of transparent quartz, both of which are concentric with a slight space therebetween. It is supported. These are supported by a support flange 30 which will be described later. The outer tube 21 has a cylindrical structure in which an upper end portion 22 is closed in a dome shape, a lower end portion 23 is opened, and a flange 24 is formed on the periphery of the opening. On the other hand, the inner pipe 25 has a cylindrical structure in which an upper end portion (not shown) and a lower end portion 26 are open, and a flange 27 is formed on the peripheral edge thereof.

The support flange 30 is a means for fixing the outer pipe 21 and the inner pipe 25 in the upper chamber 3. This support flange 30 has a U-shaped cross section,
An annular groove 32 is formed on the upper end 31 of the U-shape, and an annular flange 33 is formed on the inner peripheral surface of the U-shaped support flange 30, and the outer pipe 21 is formed in the annular groove 32. Flange 24 is inserted, sealed and fixed by an O-ring (not shown), and the annular flange 33
The flange 27 of the inner pipe 25 is mounted and fixed on the. Reference numeral 40 is a cap that moves up and down, and an O-ring 41 is attached to the peripheral portion of the upper surface thereof.
A quartz boat 8 is placed on the above, and the space between the room 4 and the room 3 is raised and lowered.

During the gas reaction, the inside of the diffusion furnace is under normal pressure,
The reaction gas is maintained at a high temperature of 00 to 1000 ° C. and introduced into the inner pipe 25 through the gas introduction port 9 and becomes an upward flow of an arrow A shown in FIG. , Is reacted and formed on each semiconductor wafer S. The unreacted gas and the reacted gas come out from the opening of the upper end portion of the inner pipe 25, are inverted at the dome that is the upper end portion 22 of the outer pipe 21, and as shown by the arrow B, The gas passes through the pipes 21 and is exhausted from the gas exhaust port 10.

As shown in FIG. 11, a plurality of sheets (not shown)
The semiconductor wafer S is housed in the quartz boat 8 and capped.
40 rises, is installed in the inner tube 25, and is sealed. Compound
Reaction gases from several gas sources, as shown in FIG.
Is nitrogen gas N₂, Hydrogen gas H ₂, Oxygen gas O₂Etc.
Mass flow controller through each gas pipe 50
The flow rate is measured at 51, and sequentially through the supply pipe 52.
Is supplied from the gas inlet 9 to the inner pipe 25 of the diffusion furnace.
It Supply of this reaction gas and control of the diffusion furnace are controlled
It will be held at La 53.

For example, a program from the controller 53
The quartz boat 8 is lifted and expanded by the controlled control signal.
Then, the tube 20 is attached to the
Heat to about 0 ° C, then place in tube 20 for a predetermined time
In between, for example, nitrogen gas N ₂5 liters of oxygen gas
O₂5 liters, hydrogen gas H₂And oxygen gas O₂5
Liters are sequentially supplied, and the surface treatment of the semiconductor wafer S is performed.
After that, the quartz boat 8 is lowered to move the semiconductor wafer S
Program control to retrieve

An exhaust pipe 54 is connected to the gas exhaust port 10, and the exhaust pipe 54 is connected to a common acid drain line 55 laid in the factory to an acid drain pipe 54A and an acid exhaust pipe 54B. It is branched. A trap 60 is connected to the acid drain pipe 54A to store water generated during hydrogen combustion oxidation (hereinafter referred to as "wet oxidation") during heat treatment. Further, as described above, although the dry oxidation by the oxygen gas O ₂ and the annealing by the nitrogen gas N ₂ are performed, the acid exhaust gas generated during the heat treatment is exhausted to the outside through the acid exhaust pipe 54B. There is.

Normally, the trap 60 has a structure as shown in FIG. That is, the trap 60 has a double structure including an inner container 61 which is cylindrical and has no lid, and an outer container 62 which is cylindrical and has a larger diameter and a longer length than this, and which has a lid. A plurality of overflow holes 63 are formed in the upper peripheral surface of the inner container 61. The acid drain pipe 54A is provided from above the outer container 62 and the inner container 61, and the inner container 6
The acid drain pipe 54 is inserted into the bottom of the outer container 62 and is connected to the acid drain line 55 from the bottom of the outer container 62.
C is out.

Therefore, the water from the acid drain pipe 54A is stored in the inner container 61 of the trap 60, and the water is flooded into the overflow hole 63.
The water flowing out of the acid drain pipe 54C is discharged from the acid drain pipe 54C to the acid drain line 55.

[0014]

The exhaust and drainage system of the diffusion furnace plays a role of collecting water generated during wet oxidation in the diffusion furnace and preventing backflow of mist and the like from the acid drainage line 55. However, when the type of heat treatment is changed from wet oxidation to dry oxidation or annealing as described above, water is not generated during these heat treatments, and high temperature acid exhaust gas is discharged, so that the trap 60 is accumulated. Water is evaporated by this hot acid exhaust gas. Therefore, if the capacity of acid exhaust is the same as during wet oxidation,
The pulling of the diffusion furnace becomes weaker, and the mist of the acid drainage line 55 is also sucked up by the acid exhaust. As a result, pressure fluctuation occurs in the diffusion furnace and the oxidation rate is changed to change the semiconductor wafer. The thickness of the oxide film to be formed on the surface of S will not be constant, or a good quality oxide film cannot be produced. An object of the heat treatment furnace device of the present invention is to solve such problems.

[0015]

Therefore, the heat treatment furnace apparatus of the present invention is provided with an emptying prevention device for preventing the evaporation of water in the trap provided in the drainage pipe constituting the drainage line, thereby solving the above-mentioned problems. are doing. First of the sky prevention device
Means comprises a cooling device, a part of the exhaust pipe inserted into the trap and the entire trap is covered with a cooling pipe having a water supply and drainage port, and during the heat treatment other than wet oxidation in a heat treatment furnace, Supplying cooling water to the cooling pipe, temperature of acid exhaust gas generated during heat treatment other than wet oxidation,
Also, the temperature of the water in the trap was prevented from rising. Further, the second means of the empty prevention device is composed of a valve, which is provided in the drain pipe immediately before the trap, and this valve is opened during the heat treatment of the wet oxidation in the heat treatment furnace, except for the wet oxidation. During this heat treatment, the valve is controlled to be closed so as to block the entry of hot air generated by heat treatment other than wet oxidation into the trap. The opening / closing of the valve may be automatically opened / closed in association with the heat treatment mode of the heat treatment furnace. Furthermore, the third means of the empty prevention device comprises a water supply pipe having a water stopper at the lower end, which is piped from the water supply line in the trap, and a detection device for detecting the water level in the trap. The water stopcock has a structure that opens and closes according to the water level in the trap. Furthermore, the fourth means of the empty prevention device is constructed by floating a float in the trap, and the float can open and close the overflow hole formed in the trap and can move up and down along the inner wall of the trap. Is taking. Furthermore, the fifth means of the empty prevention device has a structure in which an opening / closing valve provided in the middle of a pipe arranged in the trap is slightly opened to constantly supply a minimum amount of water into the trap. ing.

[0016]

Therefore, according to the heat treatment furnace apparatus of the present invention, the water in the trap can be prevented from evaporating, or the water is constantly supplied into the trap, so that the trap will not become empty. Therefore, the inside of the diffusion furnace can always be maintained at a normal pressure state without pressure fluctuation, and the backflow of mist from the acid drain line can be prevented.

[0017]

EXAMPLES Next, the heat treatment furnace apparatus of the present invention will be described with reference to FIGS. 1 to 9 by taking a vertical atmospheric diffusion furnace apparatus as an example thereof. 1 is a partial sectional perspective view of a first embodiment of a device for preventing emptying of water in a trap in a vertical atmospheric diffusion furnace apparatus of the present invention, and FIG. 2 is a vertical atmospheric diffusion furnace apparatus of the present invention. FIG. 4 is a perspective view of a second embodiment of a device for preventing emptying of water in a trap, and FIG. 3 is a system for supplying a reaction gas to a diffusion furnace of a vertical atmospheric diffusion furnace apparatus and a system for exhausting a reaction gas from the diffusion furnace FIG. 4 is a schematic diagram showing a system for controlling the device for preventing emptying of water in the trap shown in FIG. 2, and FIG. 4 is a device for preventing emptying of water in the trap in the vertical atmospheric pressure diffusion furnace device of the present invention. FIG. 5 is a conceptual cross-sectional side view of a third embodiment of the present invention, and FIG. 5 is a conceptual cross-sectional side view of a fourth embodiment of a device for preventing water in a trap in a vertical atmospheric diffusion furnace apparatus of the present invention. Yes, Figure 6
FIG. 7 is a conceptual cross-sectional side view of a fifth embodiment of a device for preventing water empty in a trap in a vertical atmospheric diffusion furnace apparatus of the present invention, and FIG. 7 is a trap in a vertical atmospheric diffusion furnace apparatus of the present invention. FIG. 9 is a conceptual cross-sectional side view of a sixth embodiment of the water empty prevention device in the present invention, and FIG. 9 is a seventh embodiment of the water empty prevention device in the trap of the vertical atmospheric diffusion furnace apparatus of the present invention. It is a conceptual cross-sectional side view of. The same parts as those of the conventional vertical atmospheric pressure diffusion furnace device are designated by the same reference numerals, and the description thereof will be omitted.

First, referring to FIG. 1, a water empty prevention device 70A in a trap according to a first embodiment of the present invention will be described. In this embodiment, the empty prevention device 70A includes a watertight cooling container 71 that surrounds the entire surface of the trap 60 and the trap 6.
No. 0 upper part of the acid drainage pipe 54A and a watertight cooling pipe 72 that surrounds a part of the acid drainage pipe 54A. The cooling pipe 72 and the cooling container 71 are communicated and connected to each other, and the side surface of the bottom surface of the cooling container 71 In order to cool the trap 60 and the acid drain pipe 54A above the trap 60, the cooling water is supplied from the water supply port 73 formed on the upper side of the cooling pipe 72 and drained from the drain port 74 formed on the peripheral surface of the upper end of the cooling pipe 72. I have to.

By using this empty prevention device 70A, even when heat treatment other than wet oxidation is performed in the diffusion furnace,
The water in the trap 60 can be cooled and its evaporation can be prevented. Further, as will be described in the second embodiment described below, the supply of the cooling water is carried out by the controller 5
The switching may be automatically performed according to the control of the diffusion furnace of No. 3. Since this empty prevention device 70A has a simple structure, it can be easily attached to existing equipment.

Next, a second embodiment of the present invention, a device for preventing emptying of water in a trap 70B, will be described with reference to FIGS. In this embodiment, the empty prevention device 70B is an opening / closing valve 75. This on-off valve 75 is inserted into the acid drain pipe 54A above the trap 60, and when the diffusion furnace is operating by wet oxidation, the on-off valve 75 is opened to drain the water vapor discharged from the exhaust pipe 54 into the acid drain. Pipe 54A
Flowing into the trap 60, water converted from water vapor can be stored in the trap 60, and when operating by heat treatment other than wet oxidation, the on-off valve 75 is closed and the hot reaction gas discharged from the exhaust pipe 54 is closed. If the acid exhaust pipe 54B is exhausted, the water in the trap 60 can be prevented from evaporating and the trap 60 can be prevented from becoming empty.

The opening / closing valve 75 can be opened / closed in conjunction with program control of the controller 53, as shown in FIG. That is, the mass flow controller 5 uses the program control signal of the controller 53 illustrated in FIG.
1 is controlled, the flow rate is adjusted under the control of the mass flow controller 51, and the time when the hydrogen gas H ₂ flows out is detected, and the on-off valve 7 is detected by the detected electric signal.
Open 5 The on-off valve 75 in this case is an electromagnetic on-off valve. In the case of heat treatment in which the supply of hydrogen gas H ₂ is stopped and the other reaction gases N ₂ , O _2, etc. are supplied, no electric signal is generated from the mass flow controller 51, so the on-off valve 75 is closed. Since the state is maintained, the water in the trap 60 does not evaporate due to the high temperature exhaust gas exhausted from the exhaust pipe 54.

Next, a water empty prevention device 70C in the trap 60 according to a third embodiment of the present invention will be described with reference to FIG. In the empty prevention device 70C of this embodiment, a pipe 76 connected to a water source such as pure water is used as an inner container 61 of a trap 60.
(In FIG. 4, only the inner container 61 of the trap 60 is shown), while the base end is vertically rotatable at the height position of the lower end opening 76A of the pipe 76 on the inner wall of the inner container 61. A rod 79 fixed to the base end is provided with a water stop 78 that is supported and has a float 77 fixed to the tip thereof and that can close the lower end opening 76A of the pipe 76 when the float 77 floats to a horizontal position. It consists of and.

In the state shown in FIG. 4A, the water W from the acid drainage pipe 54A is sufficiently accumulated in the inner container 61 of the trap 60 and overflows from the overflow hole 63, and the float 77 floats up to operate. Shows a state in which the rod 79 is rotated around the base end of the rod 79 and the water stop plug 78 closes the lower end opening 76A of the pipe 76. This state is when the heat treatment of the diffusion furnace is in a wet oxidation state, and the acid drain pipe 54A
The water W is collected in the inner container 61 one after another. On the other hand, the state shown in FIG. 4B is a state that occurs in the diffusion furnace at the time of dry processing, and shows a state in which high temperature acid exhaust gas has entered the acid drain pipe 54A and water W has evaporated at the high temperature. . In this state, the float 77 lowers according to the height of the water surface (or water level) Wh, and as a result, the water stop plug 78 separates from the lower end opening 76A of the pipe 76, that is,
Since the lower end opening 76A is opened, the water that is constantly being supplied flows out through the pipe 76, which prevents the water W in the trap 60 from becoming empty. In FIG. 4, the height of the water surface Wh is extremely expressed, and in reality, the water surface Wh only slightly moves up and down near the height position of the lower end opening 76A of the pipe 76.

FIG. 5 shows a water empty prevention device 70D in the trap 60 according to a fourth embodiment of the present invention. The sky prevention device 70D of this embodiment is provided with a lower end opening 76 of a pipe 76.
A water stopper 80 was used in place of the water stopper 78 for closing A.
As shown in the enlarged view of FIGS. 5C and 5D, the water stop plug 80 has a pipe 76 inserted into a hole 82 formed in the upper end surface of a cylindrical or rectangular parallelepiped type container 81. A collar 7 formed horizontally around the lower end opening 76A.
6B has a structure that prevents the container 81 from falling off. A plurality of water supply ports 83 are provided in the middle of the container 81.
Is formed on the bottom surface of the container 81.
4 is fixed and configured.

Next, the sky prevention device 70 having such a structure
D, that is, the operation of the water stopcock 80 will be described. Now, as shown in FIGS. 5A and 5C, during the wet oxidation or the trap 6
When water is sufficiently stored in the inner container 61 of No. 0, the water stopcock 80 is lifted by the action of the float 84 and the pipe 7
The lower end opening 76A of 6 is closed by the float 84. Therefore, the supply of pure water from the pipe 76 is stopped, and the water from the acid drain pipe 54A accumulates in the inner container 61.

However, in the case other than the wet oxidation such as the dry oxidation or the annealing, as shown in FIGS. 5B and 5D, the high temperature acid exhaust gas from the exhaust pipe 54 causes the inside of the inner container 61 to be discharged. When the water evaporates and the water surface Wh drops, and in an extreme case, the container 81 has the lower end opening 76 of the pipe 76
The collar 76B formed on A is in a suspended state.
That is, the upper surface of the float 84 has a lower end opening 76 of the pipe 76.
Since it is separated from A and opened, pure water can be supplied from the pipe 76 to the water supply port 83, and the water level Wh of the water in the inner container 61 rises. In this way, the empty prevention device 70D of this embodiment uses the trap 6
Continue to supply water to 0. Also in this FIG. 4, the height of the water surface Wh is extremely expressed, and in reality, when the water surface Wh is slightly lowered, the container 81 is only slightly lowered.

Next, FIG. 6 shows a water empty prevention device 70E in the trap 60 according to a fifth embodiment of the present invention.
In the empty prevention device 70E of this embodiment, stoppers 85A and 85B are formed on the inner peripheral surface of the lower end portion of the pipe 76 with an interval twice or more the size of the spherical float 84 (water stopcock). A plurality of water supply ports 76C are formed on the peripheral surface intermediate between these stoppers 85A and 85B, and the
4 is inserted and configured.

The emptying prevention device 70E having such a structure is inserted into the trap 60, and is used during the wet oxidation as shown in FIGS. 6A and 6C or in the inner container 6 of the trap 60.
When the water is sufficiently accumulated so that the water surface Wh is above the position of the water supply port 76C opened in the pipe 76, the float 84 floats to the stopper 85A and stops, and the pipe 76 is closed by the float 84. Therefore, the pipe 76
From this point, the supply of pure water is stopped, and the water from the acid drain pipe 54A accumulates in the inner container 61.

However, except during wet oxidation,
As shown in FIGS. 6B and 6D, the hot acid exhaust gas from the exhaust pipe 54 flows into the acid drain pipe 54A,
When the water in the inner container 61 evaporates due to the hot acid exhaust gas and the water surface Wh drops, the float 84 also stops.
Since it goes down to 5B, the water supply port 76C is opened and pure water can be supplied from the pipe 76 to the inner container 61.
The water level Wh of the water in the inner container 61 will rise. In this way, the empty prevention device 70E of this embodiment continues to supply water into the trap 60. Also in this FIG. 4, the water surface Wh
The height of the water is extremely expressed, and in fact, the water surface W
When h is slightly lowered, the float 84 is only slightly lowered.

Finally, the sky prevention device 70F of the sixth embodiment will be described with reference to FIG. The sky prevention device 70 of this embodiment
F is composed of a flat plate-shaped float (stop cock) 88 that is fitted in the inner container 61 so as to be vertically movable. The thickness of the float 88 is sufficiently thicker than the diameter of the overflow holes 63 formed on the peripheral surface of the inner container 61, and the lower surface thereof has a slightly larger arc shape corresponding to the upper half of the plurality of overflow holes 63. The concave grooves 87 are formed in the same number and at the same intervals as the overflow holes 63.

Therefore, in the wet oxidation shown in FIG. 7A, or when the water is sufficiently accumulated in the inner container 61 of the trap 60 and overflows from the overflow hole 63, the concave groove 87 of the float 88 is the overflow hole. It floats upward until it comes above 63, and the overflow hole 63 is opened. Therefore, the water W from the acid drainage pipe 54A collects in the inner container 61, and when the water W increases, it flows out from the overflow hole 63.

However, except in the case of wet oxidation,
As shown in FIG. 7B, when the high temperature acid exhaust gas from the exhaust pipe 54 flows into the acid drain pipe 54A, the high temperature acid exhaust gas evaporates the water W in the inner container 61 and lowers its water surface Wh. The float 88 also descends, and the overflow hole 63 is closed by the side surface of the float 88, and the water level Wh of the water W in the inner container 61 cannot be lowered further. In this way, the empty prevention device 70F of this embodiment can prevent the water in the trap 60 from becoming empty.

The sky prevention device 70C of the third embodiment shown in FIG. 4, the sky prevention device 70D of the fourth embodiment shown in FIG. 5, and the sky prevention device of the fifth embodiment shown in FIG. 6 have been described above. 7
In the empty prevention device 70F of the sixth embodiment illustrated in FIG. 0E and FIG. 7, each water supply pipe 76 is provided with a water stopper of each type, and each water stopper is opened during dry oxidation to supply water. The trap 61 has a water-saving structure that compensates for the evaporation of the water W. However, when it is not necessary to save water, the trap 61 always has a structure of continuously supplying a small amount of water. Preventing devices may be used.

FIG. 9 shows a water emptying prevention device in this case. That is, the sky prevention device 70G of the seventh embodiment shown in FIG.
Is an opening / closing valve 90 which is capable of adjusting the amount of water flowing in the water supply pipe 76 to the pipe 76 outside the trap 61 by installing a pipe 76 from the water supply line in the trap 61.
The opening / closing valve 90 is slightly opened to keep the trap 61 open at all times, that is, during wet oxidation and dry oxidation.
A minimum amount of water W should be supplied inside.

With this structure, the water W can be replenished in the trap 61 which is about to evaporate during the dry oxidation, and the water can be continuously supplied during the wet oxidation, but the excess water is collected through the overflow hole 63. The water can be drained to the outside of the trap 61. Therefore, since the structure of the sky prevention device 70G is simple, the equipment cost can be kept low.

In the above description, the vertical atmospheric diffusion furnace apparatus is exemplified as the thermal treatment furnace apparatus, but the thermal treatment furnace apparatus of the present invention is not limited to this vertical atmospheric diffusion furnace apparatus. Note that the present invention can be applied to a horizontal heat treatment furnace apparatus capable of wet oxidation and also to a reduced pressure heat treatment furnace apparatus.

[0037]

Therefore, according to the vertical atmospheric diffusion furnace apparatus of the present invention, evaporation of water in the trap can be prevented with a simple structure, or water is always supplied into the trap. , The trap is never emptied, so that the pressure inside the diffusion furnace can always be maintained at normal pressure without fluctuations, and it is formed on the surface of the semiconductor wafer. It is possible to improve the sex.
It is also possible to prevent the backflow of mist from the acid drain line.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view of an empty space preventive device which is a first embodiment of water in a trap in a heat treatment furnace device of the present invention.

FIG. 2 is a perspective view of an empty prevention device which is a second embodiment of the water in the trap in the heat treatment furnace device of the present invention.

FIG. 3 shows a reaction gas supply system to the diffusion furnace of the heat treatment furnace apparatus and an exhaust system of the reacted gas from the diffusion furnace, and shows a system for controlling the device for preventing water empty in the trap shown in FIG. FIG.

FIG. 4 is a conceptual cross-sectional side view of an emptying prevention device which is a third embodiment of water in a trap in the heat treatment furnace device of the present invention.

FIG. 5 is a conceptual cross-sectional side view of an empty prevention device which is a fourth embodiment of water in a trap in the heat treatment furnace device of the present invention.

FIG. 6 is a conceptual cross-sectional side view of an empty prevention device which is a fifth embodiment of water in a trap in the heat treatment furnace device of the present invention.

FIG. 7 is a conceptual cross-sectional side view of an empty prevention device which is a sixth embodiment of water in a trap in the heat treatment furnace device of the present invention.

FIG. 8 is a conceptual cross-sectional side view of an empty prevention device which is a seventh embodiment of the water in the trap in the heat treatment furnace device of the present invention.

FIG. 9 is a conceptual diagram showing a back surface of a main part of a batch-type heat treatment furnace apparatus.

10 is a perspective view of a diffusion furnace corresponding to the heart of the heat treatment furnace device shown in FIG.

FIG. 11 is a schematic diagram showing a reaction gas supply system to a diffusion furnace and a reaction gas exhaust system from the diffusion furnace of a heat treatment furnace apparatus of the prior art.

12 is a schematic view showing an enlarged structure of a trap in the heat treatment furnace device of FIG.

[Explanation of symbols]

 1 Conventional Vertical Diffusion Furnace Equipment 8 Quartz Boat 9 Gas Inlet 10 Gas Outlet 20 Tube 21 Outer Tube 22 Inner Tube 50 Gas Pipe 51 Mass Flow Controller 52 Supply Pipe 53 Controller 54 Exhaust Pipe 54A Acid Drain Pipe 54B Acid exhaust pipe 54C Acid drain pipe 55 Acid drain line 60 Trap 61 Inner container 62 Outer container 63 Overflow hole 70A Empty prevention device of the first embodiment 70B Empty prevention device of the second embodiment 70C Empty prevention device of the third embodiment 70D Empty prevention device of the fourth embodiment 70E Empty prevention device of the fifth embodiment 70F Empty prevention device of the sixth embodiment 70G Empty prevention device of the sixth embodiment 71 Cooling container 72 Cooling pipe 73 Water supply port 74 Drain port 75 Open / close valve 76 Pipe 76A Lower end opening of pipe 76 76B Tsubo 76C Water inlet 77 Float 78 Water stop 79 Rod 80 Water Stopper 81 Container 82 Hole of Container 81 83 Water Supply Port 84 Float 85A Stopper 85B Stopper 86 Float (Water Stopper) 87 Ditch Groove 88 Float (Water Stopper) 90 Semiconductor Wafer W Water Wh Water Surface ( Water level)

Claims (7)

[Claims] 1. A heat treatment furnace apparatus comprising a device for preventing emptying of water in a trap provided in a drain pipe constituting a drain line of the heat treatment furnace apparatus. 2. The empty prevention device is composed of a cooling device, and a part of an exhaust pipe inserted into the trap and the entire trap are covered with a cooling pipe having a water supply / drain port, and wet oxidation in a heat treatment furnace is performed. Cooling water is supplied to the cooling pipe during the heat treatment other than the time, and the temperature of the acid exhaust gas generated during the heat treatment other than the wet oxidation and the temperature rise of the water in the trap are prevented. Item 1. A heat treatment furnace apparatus according to Item 1. 3. The empty prevention device comprises a valve,
It is provided in the drainage pipe immediately before the trap, the valve is opened during the heat treatment of wet oxidation in the heat treatment furnace, and the valve is controlled to be closed during heat treatment other than wet oxidation, and the heat treatment other than wet oxidation is performed. The heat treatment furnace apparatus according to claim 1, wherein the generated hot air is blocked from entering the trap. 4. The heat treatment furnace apparatus according to claim 3, wherein the opening / closing of the valve is automatically opened / closed in association with a heat treatment mode of the heat treatment furnace. 5. The empty prevention device is composed of a water supply pipe having a water stopcock at a lower end portion, which is piped from a water supply line in the trap, and a detection device for detecting a water level in the trap. The heat treatment furnace apparatus according to claim 1, wherein the water shutoff valve is opened and closed according to a water level in the trap. 6. The heat treatment according to claim 1, wherein the empty prevention device is a float that can open and close overflow holes formed in the trap in the trap and can move up and down along an inner wall of the trap. Furnace equipment. 7. The empty prevention device includes a water supply pipe connected to a water supply line in the trap, and an opening / closing valve provided in the water supply pipe outside the trap and capable of adjusting the amount of water flowing in the water supply pipe. The heat treatment furnace apparatus according to claim 1, wherein the open / close valve is slightly opened to continuously supply water into the trap during heat treatment.