JP3406040B2 - Processing device and processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust treatment apparatus and an exhaust treatment method for a heat treatment apparatus.

[0002]

2. Description of the Related Art Conventionally, a heat treatment process line for semiconductor wafers or the like is generally a production line in which a large number of heat treatment furnaces equipped with process tubes are installed and the exhaust system ducts of these furnaces are commonly connected to the exhaust ducts of a factory. Are configured.
The process exhaust capacity of the heat treatment apparatus depends on the exhaust capacity of the factory where the apparatus is installed, and is desired to be constant in order to uniformly heat treat a plurality of semiconductor wafers. However, the pressure in the reaction tube, which is the process tube, often changes during the process execution.

In order to prevent the fluctuation of the pressure in the exhaust pipe caused by the fluctuation of the pressure in the reaction pipe, a technique of automatically adjusting the internal pressure by a pressure adjusting mechanism provided in the middle of the exhaust pipe to uniformly exhaust the inside of the apparatus. Japanese Patent Laid-Open No. 3-2192
There is a technique described in Japanese Patent Publication No. 00.

[0004]

However, in the above-mentioned exhaust technology, an enormous concave portion provided in the structure of the apparatus, that is, in the middle of the exhaust pipe, and an O-ring made of an elastic member at the inner edge of the concave portion are provided. A circular movable valve with a concave central part on top of the O-ring presses the O-ring under its own weight,
In the float type pressure adjusting mechanism that sets the airtight state with the atmosphere, the exhaust gas after the heat treatment flows through the exhaust pipe line connected to the process tube, and the temperature of the exhaust gas decreases as it goes downstream. The waste liquid condensed due to this temperature decrease phenomenon causes the pressure adjusting mechanism to malfunction, and the desired exhaust ratio cannot be kept constant, so that the semiconductor wafer cannot be uniformly heat-treated. Also, when the exhaust gas after the heat treatment flows through the exhaust pipe outside the reaction tube, if the temperature remains high and does not cause condensation, there is a possibility that toxic gases such as HCl may back-diffuse into the atmosphere. Has the improvements.

The present invention has been made under the circumstances as described above, and its purpose is to remove waste liquid condensed due to a decrease in temperature as the exhaust gas after heat treatment flows through the exhaust pipe outside the reaction tube. Even if it occurs in the exhaust pipe, the waste liquid is concentrated and discharged to the outside in the liquid reservoir, so that the pressure adjustment mechanism can operate normally, and the exhaust gas after heat treatment flows through the exhaust pipe outside the reaction tube. In the meantime, when the temperature remains high and does not cause dew condensation, it is possible to prevent back diffusion of toxic gas such as HCl into the atmosphere, and to provide a processing apparatus and a processing method capable of uniformly heat-treating an object. is there.

[0006]

According to a first aspect of the present invention, there is provided a reaction tube for accommodating an object to be treated and performing heat treatment, and at least one liquid reservoir provided in the middle of an exhaust pipe connected to the reaction tube. In a processing device provided with a portion, a waste liquid discharge portion connected from the liquid storage portion via a waste liquid discharge system, and a pressure adjusting mechanism, the pressure adjusting mechanism operates by sealing the periphery of the pressure adjusting mechanism. And an exhaust means for forcibly exhausting the atmosphere within the range.

According to a second aspect of the present invention, there is provided a treatment tube provided with a reaction tube for heat-treating an object, a liquid reservoir provided in at least one exhaust system provided in the reaction tube, and a pressure adjusting mechanism. In the processing method of the apparatus, the periphery of the pressure adjusting mechanism is hermetically closed, and the atmosphere is forcibly exhausted within the range in which the pressure adjusting mechanism operates.

[0008]

In the present invention, as the exhaust gas after the heat treatment flows through the exhaust pipe outside the reaction tube, the temperature of the exhaust gas decreases, and even if a condensed liquid is generated in the exhaust pipe, the waste liquid is trapped in a concentrated manner in the liquid reservoir. The waste liquid is discharged to the outside from the waste liquid discharge part connected via the waste liquid discharge pipe, so that the waste liquid does not flow into the pressure adjustment mechanism and the pressure adjustment mechanism can operate normally. While flowing through the outside exhaust pipe,
When the temperature remains high and does not completely dew, the normal operation of the pressure adjusting mechanism is maintained and the back diffusion of toxic gas such as HCl into the atmosphere is prevented.

[0009]

EXAMPLES Examples of the present invention will be specifically described below. FIG. 1 is an explanatory view showing an embodiment in which the present invention is applied to a vertical atmospheric steam oxidation heat treatment apparatus. A reaction tube made of a heat-resistant material, such as quartz, which is long in the vertical direction and has a lid on the bottom surface, for example, a vertical process tube 10, has a process gas introduction pipe 12 connected to one end thereof and a discharge pipe 13 provided at the other end thereof. ing.

A cylindrical heater, such as a resistance heater 16, is provided coaxially with the process tube 10 on the outer periphery of the side wall of the process tube 10. The process tube 10 has a predetermined heat treatment temperature, for example, 800 ° C. to 1200 ° C.
The control can be set appropriately within the range. As the objects to be processed, for example, a plurality of semiconductor wafers 17 are accommodated in a heat-resistant material, for example, a wafer boat 18 made of quartz, and the wafer boat 18 made of quartz is installed on a mounting table 19 and is predetermined in the process tube 10. It is configured to be stored in a different position, that is, in a soaking area.

The mounting table 19 described above is installed on the lid 20.
The lid 20 can be moved in the vertical direction in a state where the plurality of semiconductor wafers 17 are accommodated by the elevating mechanism 31, and the wafer boat 1 in which the semiconductor wafers 17 are accommodated.
8 is configured so that it can be carried in and out of the process tube 10.

The process gas introduction pipe 12 is constructed so that a processing gas, for example, steam from a steam generation source 32 and HCl gas from a mass flow controller 34 can be supplied.

A second exhaust pipe 21 arranged horizontally is connected to the discharge pipe 13 via a connecting valve.
A first exhaust pipe 22 in which a main cylinder is vertically arranged is coupled to the exhaust pipe 21, and a liquid reservoir 23 is provided in the middle of the first exhaust pipe 22. This liquid reservoir 23
Is intended to recirculate a part of the exhaust gas that remains vaporized at a high temperature to the scavenger section 25 while collecting the condensed waste liquid of the exhaust gas and discharging it to the outside. A pressure adjusting mechanism 40 is provided.
The pressure adjusting mechanism 40 is for automatically setting the pressure of the exhaust flow to a preset pressure.

In the scavenger section 25, a toxic gas such as HCl gas leaked from the process tube 10 and the pressure adjusting mechanism 40 is provided with a suction pipe 26, and a forced exhaust mechanism (not shown) such as a vacuum pump (not shown) is provided. No)
And so on.

Next, an example of the structure of the pressure adjusting mechanism 40 will be specifically described with reference to FIG. The first exhaust pipe 22
An enlarging concave portion 43 is provided at an end portion of the tributary pipe 41 bent downward from the middle thereof, and an O-ring 44 made of an elastic member is arranged at an inner edge of the concave portion 43. A circular movable valve 45 having a concave central portion is pressed on the upper portion of the O-ring 44, for example, by pressing the O-ring 44 by its own weight to set an airtight state between the pressure adjusting mechanism 40 and the atmosphere.

A waste liquid discharge part, for example, a waste liquid discharge mechanism 50 is connected and arranged, for example, below the connection point between the first exhaust pipe 22 and the second exhaust pipe 21 and below the liquid reservoir pipe 23, for example. . If a forced suction mechanism such as a vacuum pump is provided, it may be above. As shown in FIG. 3, the waste liquid discharge mechanism 50 includes the first exhaust pipe 22 and the liquid storage pipe 23 shown in FIG.
A waste liquid discharge pipe 51 extending from the inside of the waste liquid container, for example, a waste liquid reservoir 52, is inserted and disposed, and at least one hole 54 is provided in the upper portion of the waste liquid reservoir 52. It is configured so as to overflow from the portion 54, and the periphery of the waste liquid storage portion 52 is configured to be sealed by an outer case 56. With this overflow structure, direct connection with the common waste liquid pipe 63 is avoided and turbulence of the exhaust flow is prevented.

In this way, a single-system heat treatment apparatus is constructed. Such a heat treatment apparatus is arranged in parallel in a plurality of systems in a semiconductor manufacturing factory, and the exhaust system and the waste liquid discharge system are finally assembled into one system.

That is, the exhaust drive of a plurality of process tubes 10 is installed in the common exhaust pipe 61 and the exhaust capacity is large.
The two exhaust fans 62 are configured to exhaust the air. The exhaust fan 62 may be configured by a vacuum pump, for example.

Further, the exhaust liquid after the heat treatment of the plurality of process tubes 10 is condensed by the temperature of the exhaust gas being lowered as it flows through the exhaust pipe line, and the waste liquid is discharged from the waste liquid discharge mechanism 50 through the common waste liquid discharge pipe 63. Is configured.

The process gas introduction pipe 12, the discharge pipe 13, and the second pipe which come into contact with a high temperature gas and a corrosive gas such as HCl.
The exhaust pipe 21, the first exhaust pipe 22, the liquid collecting pipe 23, the suction pipe 26, the pressure adjusting mechanism 40, the waste liquid discharging mechanism 50, the waste liquid discharging pipe 51, and the common waste liquid discharging pipe 63 are non-metal, for example, It is composed of a heat and corrosion resistant member such as quartz or fluororesin.

As described above, since the exhaust system of many atmospheric pressure heat treatment apparatuses is unified into one system, it is necessary to keep the total exhaust amount constant. Therefore, the pressure adjusting mechanism 40 and the waste liquid discharging mechanism 50 are provided in the exhaust pipe line of each system as means for keeping the exhaust amount constant.

Next, the operation of the above embodiment will be described. In a state where the processing gas is supplied to one of the plurality of process tubes 10 and the processing gas is not supplied to the other process tubes 10 and the lid 20 is closed, the exhaust fan 62 is Since the flow rate of the processing gas flowing with respect to the exhaust capacity is small, the pressure in the first exhaust pipe 22 becomes relatively large and becomes a negative pressure state.

As a result, the movable valve 4 is weighed more than the movable valve 45.
The force of the differential pressure applied to 5 is increased, the movable valve 45 is largely lifted, and the atmosphere in the scavenger portion 25 flows into the first exhaust pipe 22 through the concave portion 43, and the internal pressure is always maintained at a predetermined pressure. .

At this time, the scavenger portion 25 to the suction pipe 2
When forcedly exhausted via 6, the exhaust capacity must be lower than the exhaust capacity of the exhaust fan 62. Further, even if the toxic exhaust gas diffuses back from the pressure adjusting mechanism 40,
Since it is inside the closed scavenger section 25, the safety of factory workers is ensured.

Further, in a state where the lid 20 is opened to carry the semiconductor wafer 17 into another process tube 10,
A large amount of atmospheric air is discharged from the process tube 10 to the first exhaust pipe 2
It flows into 2, and the internal pressure rises.

At this time, the opening degree of the movable valve 45 of the pressure adjusting mechanism 40, which has been wide open up to now, becomes narrow, and the desired pressure is stabilized. In this way, the pressure adjusting mechanism 40
The opening degree of the movable valve 45 changes according to the pressure in the first exhaust pipe 22, and operates so that a desired pressure is always maintained.
Even when the flow rate of the gas flowing through the process tube 10 is changed in order to change the process state, the movable valve 45 of the pressure adjusting mechanism 40 operates in the same manner as described above, and the desired pressure is always maintained.

For the waste liquid, the resistance heater 16 is used.
By setting the soaking region in the process tube 10 to an oxidation treatment temperature, for example, a temperature of 1000 ° C., steam and HCl gas as a treatment gas are supplied to the object to be treated, for example, the semiconductor wafer 17 accommodated in the process tube 10. To do. Then, after passing through the inside of the process tube 10 and being exhausted, the water vapor is cooled on the inner wall of the first exhaust pipe 22, the waste liquid containing HCl falls along the inner wall of the first exhaust pipe 22, or the liquid collecting pipe. 23 is intensively captured, passes through the waste liquid pipe 51, and overflows from the waste liquid reservoir 52 of the waste liquid discharge mechanism 50.
Discharge to the common waste liquid discharge pipe 63.

The effects of the above embodiment will be described below. According to the present invention, as the exhaust gas after the heat treatment flows through the exhaust pipe line outside the process tube 10, the temperature of the exhaust gas decreases, so that even if a waste liquid is formed in the exhaust pipe line due to dew condensation, the waste liquid is discharged through the waste liquid discharge pipe 51. Can be discharged. Further, the waste liquid is prevented from leaking to the outside without flowing into the pressure adjusting mechanism 40, which enables the movable valve 45 to operate normally.

Therefore, even in the heat treatment, a large amount of water vapor is caused to flow as in the wet oxidation treatment, and no matter how much the waste liquid becomes, the waste liquid causes the first exhaust pipe 22 and the second exhaust pipe 21.
Is not blocked, and desired processing can be performed without variations between the semiconductor wafers 17.

Further, according to the present invention, while the exhaust gas after the heat treatment flows through the exhaust pipe outside the reaction pipe, even if the temperature is high and there is no dew condensation, back diffusion of toxic gas such as HCl into the atmosphere is prevented. To do. Therefore, the safety of the factory worker can be ensured, and the process gas flowing in the process tube 10 can be uniformly exhausted, so that the gas flow in the apparatus is not disturbed and the in-plane uniformity of the surface of the semiconductor wafer 17 is good. Can be processed.

Further, even if a corrosive gas such as HCl is flowed, the waste liquid discharge mechanism 50 is composed of a non-metal corrosion resistant member, so that no corrosion occurs.

Next, another embodiment of the present invention will be described. As shown in FIG. 4, the exhaust pipe 13 is connected to a second exhaust pipe 21 which is horizontally arranged via a coupling valve, and the second exhaust pipe 21 has a first cylinder in which a main cylinder is vertically arranged. Exhaust pipe 22 is connected. The first exhaust pipe 22 is provided with a liquid collecting portion, for example, a liquid collecting pipe 23 curved in a key shape or a U shape, in a branch pipe 41 provided in a branch in the middle of the pipe. A pressure adjusting mechanism 40 is provided at an end of a branch pipe 41 that is bent downward through the liquid reservoir 23.

Further, the circumference of the pressure adjusting mechanism 40 is sealed with a cover 65 and is connected to a common exhaust pipe 61 via a valve 66. With this valve 66, the atmosphere in the cover 65 is set to a positive pressure higher than that in the common exhaust pipe 61.

Further, if a cooling unit is provided in the exhaust passage, the exhaust gas is forcibly liquefied by this cooling unit, and a liquid reservoir is provided in this liquefaction unit, the liquid reservoir may be provided in one place in this case as well. . Since the other parts in FIG. 4 are the same as those of the first embodiment, the same parts are designated by the same reference numerals and the description thereof will be omitted.

The operation of this embodiment will be described. As in the first embodiment, the opening degree of the movable valve 45 of the pressure adjusting mechanism 40 changes according to the pressure in the first exhaust pipe 22 and is always desired. Even when the flow rate of the gas flowing through the process tube 10 is changed so as to maintain the pressure and change the process state, the movable valve 45 of the pressure adjusting mechanism 40 is operated similarly to the above, and the desired pressure is constantly maintained. Kept in. The waste liquid also passes from the liquid storage pipe 23 through the waste liquid discharge pipe 51, overflows from the liquid reservoir 55 of the waste liquid discharge mechanism 50, and is discharged to the common waste liquid discharge pipe 63. Also, from the pressure adjusting mechanism 40 to H
No toxic exhaust gas such as Cl will leak into the factory.

In this embodiment, compared with the first embodiment, even in the apparatus conventionally installed in the factory, by partially modifying the exhaust system, there is no variation between processed wafers. Desired processing such as can be performed.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention.

The present invention is not necessarily applied to a plurality of process tubes having a common exhaust drive source, and the first exhaust pipe 22 is a single process tube 1.
Even if it is provided exclusively for 0, the flow rate of the processing gas may be changed to change the process state, or the performance of the exhaust fan 25 may be changed due to fluctuations in the power supply voltage and the like. Is useful.

The weight of the movable valve 45 of the pressure adjusting mechanism 40 can be adjusted at a desired pressure, or the movable valve 45 can be adjusted.
It is also useful in practicing the invention to push or pull the spring.

Furthermore, the present invention is not limited to a heat treatment furnace such as an oxidation furnace or a diffusion furnace, and it goes without saying that it may be applied to an atmospheric pressure CVD apparatus or other atmospheric pressure processing apparatus. Further, it goes without saying that the invention can be applied not only to the vertical apparatus but also to horizontal apparatuses such as a horizontal heat treatment furnace.

Furthermore, the present invention is not limited to batch processing,
It goes without saying that the same effect can be obtained by the single-wafer processing.

[0042]

According to the present invention, as the exhaust gas after the heat treatment flows through the exhaust pipe outside the reaction tube, the temperature of the exhaust gas decreases, so that even if a waste liquid is formed in the exhaust pipe due to dew condensation, the waste liquid is exhausted through the exhaust pipe. Since the waste liquid is discharged to the outside from the connected waste liquid discharge part, the waste liquid does not flow into the pressure adjusting mechanism and enables the pressure adjusting mechanism to operate normally, and while the exhaust gas after heat treatment flows through the exhaust pipe outside the reaction tube. When the temperature remains high and does not completely dew, the normal operation of the pressure adjusting mechanism is maintained and the back diffusion of toxic gas such as HCl into the atmosphere is prevented.
Therefore, the desired uniform heat treatment can be performed safely and without variations between the processed wafers.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention applied to a vertical heat treatment apparatus.

FIG. 2 is an explanatory view showing a pressure adjusting mechanism of FIG.

FIG. 3 is an explanatory view showing the waste liquid discharge mechanism of FIG. 1.

FIG. 4 is an explanatory view showing another embodiment of the present invention applied to a vertical heat treatment apparatus.

[Explanation of symbols]

10 process tubes 17 Semiconductor wafer 18 wafer boat 21 Second exhaust pipe 22 First exhaust pipe 23 Liquid Reservoir 25 Scavenger Club 26 Suction tube 40 Pressure adjustment mechanism 50 Waste liquid discharge mechanism 51 Waste liquid discharge pipe 52 Waste liquid reservoir 55 Waste liquid 65 Cover 66 valves

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/22 H01L 21/324 H01L 21/205

Claims (4)

(57) [Claims] 1. A reaction tube for accommodating an object to be treated and performing heat treatment, a liquid reservoir provided at least one in the middle of an exhaust pipe connected to the reaction tube, and a waste liquid discharge pipe from the liquid reservoir. In a processing device provided with a waste liquid discharge part connected via a pressure adjusting mechanism, for sealing the periphery of the pressure adjusting mechanism, for forcibly exhausting the atmosphere within the range in which the pressure adjusting mechanism operates. A processing apparatus comprising: an exhaust unit. 2. A processing method of a processing apparatus, comprising: a reaction tube for heat-treating an object to be processed; a liquid reservoir provided in at least one exhaust system provided in the reaction tube; and a pressure adjusting mechanism. A processing method characterized in that the periphery of the pressure adjusting mechanism is hermetically closed and the atmosphere is forcibly exhausted within a range in which the pressure adjusting mechanism operates. 3. A processing section for processing an object to be processed, a liquid storage section provided at least one in the middle of an exhaust system connected to the processing section, and connected from the liquid storage section via a waste liquid discharge pipe. In the processing device provided with the waste liquid discharging section and the pressure adjusting mechanism, the exhaust means for sealing the periphery of the pressure adjusting mechanism and forcibly exhausting the atmosphere within the range in which the pressure adjusting mechanism operates, and A processing device comprising: 4. A processing method of a processing apparatus comprising a processing section for processing an object to be processed, a liquid storage section provided in at least one exhaust system provided in the processing section, and a pressure adjusting mechanism. A processing method characterized in that the periphery of the pressure adjusting mechanism is hermetically closed and the atmosphere is forcibly exhausted within a range in which the pressure adjusting mechanism operates.