JP2007150138A - Vapor phase epitaxial growth system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase epitaxial growth system capable of performing a vapor phase epitaxial growth of wafer or a maintenance of furnace safely and efficiently, even under hybrid furnace conditions of operation and standby. <P>SOLUTION: The vapor phase epitaxial growth system is equipped with at least a plurality of reactors for performing the vapor epitaxial growth with respect to a wafer, and a scrubber processing exhaust gas. Each of the plurality of reactors is connected with at least 3 gas exhaust lines that are independent of each other, respectively. A first line is connected to the scrubber so as to process the exhaust gas; a second line is used for purging air in the reactor; and a third line is used for releasing the pressure in the reactor. The first and second gas exhaust lines are equipped with valves for switching exhausting and shutting, and an exhaust gas by making only either side pass through only either of the reactors, and the third gas exhaust line is equipped with a valve for releasing pressure, which automatically opens when the pressure in the reactor reaches a prescribed value or higher. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vapor phase epitaxial growth apparatus having a plurality of reaction furnaces, and more particularly to a vapor phase epitaxial growth apparatus having a scrubber for treating waste gas exhausted from a plurality of reaction furnaces.

  For example, when a silicon single crystal layer is grown on a wafer by vapor phase epitaxial growth, a vapor phase epitaxial growth apparatus 301 as shown in FIG. 3 is generally used. FIG. 3 is a schematic diagram of a conventional vapor phase epitaxial growth apparatus. For example, a raw material gas supply apparatus 304 that supplies a raw material gas or a carrier gas that is a raw material of a silicon single crystal to be stacked, and a purge gas for purging air or the like Purge gas supply device 306, a reaction furnace 302 for epitaxial growth on a wafer inside, and a scrubber 303 for processing waste gas discharged from the reaction furnace 302.

  As shown in FIG. 3, in this conventional vapor phase epitaxial growth apparatus 301, a reaction furnace 302 and a scrubber 303 correspond one-on-one, and a scrubber 303 is provided for each reaction furnace 302. However, when the scrubber 303 is arranged for each reaction furnace 302 as described above, the scale of the vapor phase epitaxial growth apparatus 301 is increased, the occupied space is increased, and the cost for the installed scrubber is increased. Therefore, there is a problem that productivity is lowered. In particular, as the diameter of epitaxial wafers has increased in recent years, the number of single-wafer reactors has increased, and the amount of exhaust gas per reactor is relatively small compared to the batch system. Therefore, one scrubber is required for each reactor. The provision has become unrealistic in terms of cost.

  In contrast to the above-described configuration, for example, as disclosed in Patent Document 1, the scrubber 403 (collective scrubber) that processes waste gas from a plurality of reactors 402 as shown in FIG. For example, a vapor phase epitaxial growth apparatus 401. With such a vapor phase epitaxial growth apparatus 401, gas from a plurality of reactors can be processed together for one scrubber, so that the above-mentioned problems such as occupied space and cost can be alleviated. Is possible.

  However, as shown in FIG. 4, in the case of an apparatus that causes a scrubber to process waste gas from a plurality of reactors, one reactor is used as compared to the case where the reactor and scrubber are in a one-to-one configuration as shown in FIG. There is a high possibility that the trouble that occurred in this will affect other reactors, and the risk will increase.

  For example, if vapor phase epitaxial growth is performed in one of the above reactors and the reaction is stopped in another reactor due to maintenance such as wafer replacement or wall depot removal, stop the reactor. It is conceivable that air flows into another reactor or scrubber during operation from another reactor. In this way, if air and flammable gas in the reaction furnace or the like and by-products of epitaxial reaction (laminated laminates, etc.) are mixed, a problem in terms of safety arises.

  Further, for example, when the piping is clogged due to the lamination of reaction by-products, the pressure in the reaction furnace rises abnormally, and as a result, the reaction furnace may be damaged.

JP-A-10-214788

  The present invention has been made in view of such problems, and even when a reactor that is in operation and in shutdown is mixed, the vapor phase epitaxial growth of the wafer and the maintenance of the reactor can be safely and efficiently performed. An object of the present invention is to provide a vapor phase epitaxial growth apparatus that can be used.

  In order to solve the above problems, the present invention provides at least a plurality of reaction furnaces for performing vapor phase epitaxial growth on a wafer, and a gas phase provided with a scrubber for treating waste gas exhausted from the plurality of reaction furnaces. In the epitaxial growth apparatus, each of the plurality of reactors is connected to at least three gas exhaust lines provided independently of each other, and a first line is connected to the scrubber and the plurality of reactors The second line is for purging the air in the reactor, and the third line is for releasing the pressure in the reactor. The first gas exhaust line and the second gas exhaust line are each provided with a valve for switching between exhaust and exhaust stop. The gas is exhausted through only one of the first gas exhaust line and the second gas exhaust line for each reaction furnace, and the third gas exhaust line has a predetermined pressure in the reactor. A vapor phase epitaxial growth apparatus characterized by comprising a pressure relief valve that automatically opens when a value equal to or greater than the value is reached.

  Thus, in the vapor phase epitaxial growth apparatus of the present invention, each of the plurality of reaction furnaces is connected to at least three gas exhaust lines provided independently of each other. The first line is for treating waste gas exhausted from the plurality of reactors connected to the scrubber, and the second line is for purging air in the reactors. The third line is for releasing the pressure in the reactor.

  The first gas exhaust line and the second gas exhaust line include a valve for switching between exhaust and exhaust stop, and the first gas exhaust line and the second gas exhaust line are provided for each reactor by switching the valve. Since the gas is exhausted through only one of the second gas exhaust lines, for example, the air from the reactor that has been shut down is mixed with the waste gas in the reactor or scrubber that is performing vapor phase epitaxial growth. Can be prevented and can be operated safely.

Further, since the third gas exhaust line is provided with a pressure relief valve that automatically opens when the pressure in the reaction furnace reaches a predetermined value or more, the pressure in the reaction furnace becomes abnormal. Since the pressure relief is automatically performed by the pressure relief valve when it rises, it is possible to effectively prevent the reactor and the like from being damaged, and the safety during operation is also increased.
In addition, the said predetermined value can be suitably set according to the reactor used for vapor phase epitaxial growth, raw material gas, etc.

  Since the present invention includes a scrubber for treating the waste gas exhausted from the plurality of reactors, it is possible to suppress an increase in cost due to capital investment such as the occupied space and the scrubber. For this reason, it is possible to perform epitaxial growth on the wafer efficiently, with high productivity and at low cost.

At this time, the pressure relief valve is preferably a manometer.
As described above, if the pressure relief valve is a manometer, the pressure that is abnormally increased in the reaction furnace can be relieved, and damage to the reaction furnace or the like can be effectively prevented without cost. It is possible.

Furthermore, it is preferable that the reactor, the first gas exhaust line, and the second gas exhaust line are connected by a three-way valve.
Thus, if the reaction furnace, the first gas exhaust line, and the second gas exhaust line are connected by a three-way valve, the first gas exhaust line and the second gas exhaust line are more reliably provided. It is possible to exhaust the gas from the reactor through only one of the above. For this reason, waste gas and air are not more reliably mixed in the reaction furnace or scrubber, and safety can be further improved.

Further, it is preferable that a system for automatically controlling opening and closing of the valve is provided.
In this way, if a system that automatically controls the opening and closing of the valve is provided, the valve is automatically opened and closed without human intervention, so that the valve can be switched more accurately. is there.

  With such a vapor phase epitaxial growth apparatus of the present invention, since a scrubber corresponding to a plurality of reactors is provided, it is possible to perform vapor phase epitaxial growth on the wafer efficiently at low cost, It is possible to reliably prevent the waste gas such as scrubber and the air from the stopped reactor from mixing. Moreover, it is possible to effectively prevent the reactor and the like from being damaged due to an abnormal increase in the pressure in the reactor during operation.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.
In a conventional vapor phase epitaxial growth apparatus, if the reaction furnace and the scrubber are configured in a one-to-one relationship, the space occupied by the apparatus increases, the cost for the equipment increases, and the production efficiency decreases. Further, in a vapor phase epitaxial growth apparatus equipped with a conventional scrubber corresponding to a plurality of reaction furnaces, a trouble occurring in one reaction furnace is likely to affect other reaction furnaces, resulting in a high risk.

For example, gas phase epitaxial growth is stopped, air enters from a reactor under maintenance, the air reaches another reactor or scrubber in operation, and air may be mixed into the raw material gas or waste gas Sex. In particular, when combustible gas is contained in the raw material gas or the waste gas, a problem arises in terms of safety.
In addition, for example, when piping is clogged due to the stack of by-products generated in the reactor, the waste gas does not flow to the scrubber, the pressure in the reactor rises abnormally, and the reactor is damaged. There was a problem of doing.

  Therefore, the present inventors conducted extensive research on the vapor phase epitaxial growth apparatus, and in the vapor phase epitaxial growth apparatus equipped with a scrubber corresponding to a plurality of reaction furnaces, each reaction furnace is provided at least independently of each other. The first to third gas exhaust lines are connected to the first gas exhaust line for treating waste gas and the valves provided in the second gas exhaust line for purging air are switched. If the gas is exhausted through only one of the first gas exhaust line and the second gas exhaust line, for example, air entering from one reaction furnace is mixed into waste gas in another reaction furnace or scrubber I found that I can prevent it.

  If the third gas exhaust line for releasing the pressure in the reactor is equipped with a pressure relief valve that automatically opens when the pressure in the reactor reaches a predetermined value or more, The present inventors have found that it is possible to effectively prevent damage to the reaction furnace and the like due to abnormal pressure increase in the reaction furnace.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
1 and 2 are schematic views showing an example of a vapor phase epitaxial growth apparatus according to the present invention. As shown in FIG. 1, the vapor phase epitaxial growth apparatus 1 of the present invention has a plurality of reaction furnaces 2, and a configuration in which a collective scrubber 3 is installed so as to process waste gas from the plurality of reaction furnaces 2. It has become. With such a configuration, it is possible to suppress the number of scrubbers 3 to be installed, save space and cost, and perform vapor phase epitaxial growth on the wafer efficiently and with high productivity.
The number of scrubbers 3 is not limited to one as long as it accepts waste gas from a plurality of reactors, and a plurality of scrubbers 3 may be provided. For example, a plurality of scrubbers 3 may be provided corresponding to the raw material gas used, and different waste gases generated in the reaction furnace 2 may be treated separately. Moreover, what is necessary is just to determine the number of scrubbers according to the processing capacity of a scrubber according to the installation number of reactors.

  As the reaction furnace 2, for example, a quartz furnace can be used, but is not particularly limited. Also, the scrubber 3 can be, for example, one containing a filler or one having a porous plate disposed therein, and is not limited. Any one that can sufficiently treat the waste gas exhausted from the plurality of reactors 2 may be used, and an appropriate one can be installed according to the type and amount of the waste gas. As the reaction furnace 2 and the scrubber 3, those conventionally used can be installed.

  The reactor 2 is connected to a device 4 for supplying a raw material gas and a carrier gas introduced into the reactor 2 during vapor phase epitaxial growth, and a device 6 for supplying a gas for purging air and the like. In addition, a valve 5 is provided between the raw material gas supply device 4 and the purge gas supply device 6 and each reaction furnace 2 so that the gas supply can be switched for each reaction furnace 2. .

Each reactor 2 is connected to at least three gas exhaust lines (7, 8, 9) provided independently of each other as described below. An inert gas such as nitrogen is preferably allowed to flow through each gas exhaust line.
First, the first gas exhaust line 7 is for treating the waste gas exhausted from the reaction furnace 2, and connects the reaction furnace 2 and the scrubber 3. That is, it is a flow path for sending waste gas from the reaction furnace 2 to the scrubber 3.

Next, the second gas exhaust line 8 is a line for purging air in the reaction furnace 2. This line is not connected to the scrubber 3 to which the first gas exhaust line 7 is connected, and is open to the outside.
The third gas exhaust line 9 is for releasing the pressure in the reaction furnace 2. The third gas exhaust line 9 is provided with a pressure relief valve 11 that automatically opens when the pressure in the reaction furnace 2 reaches a predetermined value or higher. When the gas exhaust line 7 is blocked and the pressure in the reactor 2 rises and takes an abnormal value above the predetermined value, the valve 11 is opened to release the abnormal pressure and react. It is possible to effectively prevent the furnace 2 and the line from being damaged by pressure. Moreover, at the normal time, it can play a role of monitoring the clogging state in the first gas exhaust line 7 and the second gas exhaust line 8, which is effective for daily inspection and management.

An example of the pressure relief valve 11 is a manometer 14. If it is manometer 14, it can be set as the structure which can escape the pressure which increased abnormally effectively, without incurring cost. The manometer 14 has, for example, a U-shaped tube shape or an inclined shape, but is not particularly limited, and can release the pressure when an abnormal pressure exceeding the predetermined value is applied to the reactor 2. It ’s fine. Moreover, the liquid put into the manometer 14 can be appropriately selected according to the predetermined value. For example, those used as vacuum oil are suitable.
As described above, the predetermined value can be appropriately set according to the experimental conditions such as the material of the reaction furnace 2, the flow rate of the source gas, the set temperature at the time of vapor phase epitaxial growth, the growth rate, and the like.

  In the example shown in FIG. 1, the ends of the second gas exhaust line 8 and the third gas exhaust line 9 opposite to the side connected to the reactor 2 are opened to the outside. Accordingly, a scrubber different from the scrubber 3 connected to the first gas exhaust line 7 may be newly provided and exhausted to the outside through the scrubber.

Next, the relationship between the first gas exhaust line 7 and the second gas exhaust line 8 will be described.
Both the lines 7 and 8 are provided with a valve 10 for switching between exhaust and exhaust stop. The gas is exhausted through only one of the valves 10'a of the first gas exhaust line 7 and the valve 10'b of the second gas exhaust line 8.

  An example will be described with reference to FIG. In this vapor phase epitaxial growth apparatus 1 ′, a case where a reaction furnace 2 ′ is in operation and another reaction furnace 2 ″ is stopped due to loading / unloading of the wafer, maintenance of the furnace, etc. will be described. In the reactor 2 ″, the valve 10 ″ b of the second gas exhaust line 8 for air purge is opened, and the valve 10 ″ a of the first gas exhaust line 7 for waste gas treatment is closed. It has become. Further, the valves 10'a and 10'b of both lines 7 and 8 of the reactor 2 'in operation are in the opposite state. Therefore, the air that has entered from the stopped reactor 2 ″ does not enter the scrubber 3 through the first gas exhaust line 7, and passes through the second gas exhaust line 8 in the reactor 2 ′ that is in operation. It is possible to prevent air and waste gas from being mixed in without entering the reactor. Also, the waste gas enters the reactor 2 "that is stopped through the first gas exhaust line 7 from the reactor 2 'that is in operation. I don't have to. When performing vapor phase epitaxial growth, for example, hydrogen or the like is used as a carrier gas, or a combustible gas is contained in the waste gas. Therefore, it is important in safety to prevent mixing with air. Thus, while performing vapor phase epitaxial growth, operations such as maintenance can be performed simultaneously and safely in another reactor.

  Further, as shown in FIG. 1, a computer 13 is arranged so that the opening and closing of these valves can be automatically controlled, and one of the valves 10′a and 10′b provided in both lines 7 and 8 is opened. In this case, the opening and closing can be controlled in conjunction with each other so that the other is closed. With such a system, the valve 10 can be automatically opened and closed by a computer 13 without human intervention, so that it is possible to switch the valve 10 accurately without any human error. It is possible to increase safety.

  Further, as shown in FIG. 2, the reactor 2 ′ or the reactor 2 ″, the first gas exhaust line 7 and the second gas exhaust line 8 are connected by three-way valves 12 ′ and 12 ″. Thus, the vapor phase epitaxial growth apparatus 1 ′ can be operated more safely. By connecting with the three-way valves 12 ′ and 12 ″, the first gas exhaust line 7 and the second gas exhaust line 8 are surely connected from the reactor 2 ′ or the reactor 2 ″ without being blocked. Gas can flow only to one of them.

  Further, it is better that the connection direction of the three-way valves 12 ′ and 12 ″ is controlled by the computer 13 and linked with the operation of the reaction furnace 2 ′, the reaction furnace 2 ″, and the gas supply device 4. For example, when the reaction furnace 2 ′ or the reaction furnace 2 ″ is connected to the second gas exhaust line 8 for air purge by the three-way valves 12 ′ and 12 ″ by the interlock function, the source gas supply device 4, the reaction A system is constructed so that a combustible gas such as hydrogen cannot flow from the furnace 2 ′ or the reaction furnace 2 ″, and it is possible to prevent such combustible gas and air from being mixed. In addition, a system in which the direction of the three-way valves 12 ′ and 12 ″ is switched by a signal from the reactor 2 ′ or the reactor 2 ″ may be constructed. For example, the reactor 2 before vapor phase epitaxial growth. When a signal indicating completion of pre-purge for removing air from the reactor 2 "is issued from the reactor 2 'or the reactor 2", the reactor 2' or A system in which the direction of the three-way valves 12 ′ and 12 ″ connected to the second gas exhaust line 8 from the reactor 2 ″ is changed and connected to the first gas exhaust line 7 is conceivable. The control interlocking with the reaction furnace 2 ″, the raw material gas supply device 4 and the like can naturally be performed on the valves 10 provided in each line.

  With the vapor phase epitaxial growth apparatus 1, 1 ′ as described above, the waste gas from the plurality of reactors 2 is processed per scrubber 3 as described above, so that the efficiency is high and the productivity is high. In the reactor 2 and the scrubber 3, etc., waste gas and air are not mixed, and vapor phase epitaxial growth is performed on the wafer in one reactor 2 ′, while another reactor 2 ″ is stopped and maintenance work is performed. In addition, since the line 9 is provided for depressurization when the pressure in the reactor 2 is abnormally increased, the apparatus can be effectively prevented from being damaged. Can be safe.

  Next, a process for vapor phase epitaxially growing a silicon single crystal layer on a wafer using such a vapor phase epitaxial growth apparatus 1, 1 'will be described. As an example, a case will be described in which the vapor phase epitaxial growth apparatus 1 ′ of FIG. 2 is used and vapor phase epitaxial growth is performed on the wafer in the reaction furnace 2 ′ and maintenance of another reaction furnace 2 ″ is performed at the same time.

  In the reaction furnace 2 ′, first, after placing a wafer on the susceptor, the reaction furnace 2 ′ is closed and pre-purge is performed. At this time, the valve 10'a of the first gas exhaust line 7 is closed by the control of the computer 13, and the valve 10'b of the second gas exhaust line 8 and the valve 10'c of the third gas exhaust line 9 are opened. ing. At this time, the three-way valve 12 'is connected from the reaction furnace 2' to the second gas exhaust line 8. An inert gas such as nitrogen is flowed from the purge gas supply device 6 to purge the air in the reaction furnace 2 ′ through the second gas exhaust line 8 and to fill the reaction furnace 2 ′ with the inert gas. When the inside of the reaction furnace 2 ′ is sufficiently filled with the inert gas, a pre-purge completion signal is issued from the reaction furnace 2 ′. With this completion signal, the connection direction of the three-way valve 12 ′ is automatically switched, and the reaction furnace 2 'Leads to the first gas exhaust line 7. At the same time, the valves 10'a and 10'b are automatically switched, the valve 10'a is opened, and the valve 10'b is closed.

Next, the reaction furnace 2 ′ is heated by, for example, a lamp heater or the like, and, for example, trichlorosilane as a source gas and hydrogen as a carrier gas are supplied from the source gas supply apparatus 4 to the reaction furnace 2 ′. Then, vapor phase epitaxial growth can be performed on the wafer in the reactor 2 ′, and a silicon single crystal layer can be laminated on the wafer surface.
At this time, the waste gas discharged from the reaction furnace 2 ′ is sent to the scrubber 3 through the first gas exhaust line 7, exhausted, and then exhausted to the outside.

  Then, after laminating the silicon single crystal layer to a desired thickness, the supply and heating of the source gas and carrier gas are stopped, and the inert gas is supplied again to fill the reaction furnace 2 'with the inert gas. Thereafter, the three-way valve 12 'and the valves 10'a and 10'b are switched to connect the reaction furnace 2' to the second gas exhaust line 8, and the wafer is taken out and replaced.

  Further, for example, when the first gas exhaust line 7 is clogged with by-products generated by the reaction during operation, the pressure in the reaction furnace 2 ′ and the piping is increased. The waste gas is bubbled through the silicone oil and exhausted from the third gas exhaust line 9 together with an inert gas such as nitrogen. As a result, the abnormal pressure generated during operation can be released, and vapor phase epitaxial growth can be performed safely.

  On the other hand, the reactor 2 ″ is under maintenance, and the valve 10 ″ b of the second gas exhaust line 8 and the valve 10 ″ c of the third gas exhaust line 9 are opened by the control of the computer 13, and the first gas exhaust is performed. The valve 10 "a of the line 7 is closed, and the reactor 2" and the second gas exhaust line 8 are connected by a three-way valve 12 ". Therefore, the air that has entered from the reaction furnace 2 ″ is purged from the second gas exhaust line 8 and is exhausted to the outside without being mixed with the waste gas exhausted from the reaction furnace 2 ′ and without passing through the scrubber 3. In addition, even if the waste gas exhausted from the reaction furnace 2 ′ flows in the direction of the reaction furnace 2 ″ through the first gas exhaust line 7, the flow is blocked by the valve 10 ″ a and the three-way valve 12 ″, It can be surely prevented from mixing with air.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

It is the schematic which shows an example of the vapor phase epitaxial growth apparatus of this invention. It is the schematic which shows another example of the vapor phase epitaxial growth apparatus of this invention. It is the schematic which shows an example of the conventional vapor phase epitaxial growth apparatus. It is the schematic which shows another example of the conventional vapor phase epitaxial growth apparatus.

Explanation of symbols

1, 1 '... vapor phase epitaxial growth apparatus of the present invention,
2, 2 ', 2 ", 302, 402 ... reactor,
3, 303, 403 ... Scrubber,
4, 304, 404 ... Raw material gas supply device,
5, 10, 10'a, 10'b, 10'c, 10 "a, 10" b, 10 "c ... valve,
6, 306, 406 ... purge gas supply device, 7 ... first gas exhaust line,
8 ... Second gas exhaust line, 9 ... Third gas exhaust line,
11 ... Pressure relief valve, 12 ', 12 "... Three-way valve, 13 ... Computer,
14 ... Manometer, 301, 401 ... Conventional vapor phase epitaxial growth apparatus.

Claims (4)

  A vapor phase epitaxial growth apparatus comprising at least a plurality of reactors for performing vapor phase epitaxial growth on a wafer and a scrubber for treating waste gas exhausted from the plurality of reactors, wherein the plurality of reactors Are connected to at least three gas exhaust lines provided independently of each other, and the first line is connected to the scrubber to treat waste gas exhausted from the plurality of reactors. The second line is for purging air in the reactor, the third line is for releasing the pressure in the reactor, and the first gas exhaust line And the second gas exhaust line is provided with a valve for switching between exhaust and exhaust stop, and by switching the valve, the first gas exhaust line is provided for each reactor. The gas is exhausted through only one of the gas exhaust line and the second gas exhaust line, and the third gas exhaust line is automatically opened when the pressure in the reactor reaches a predetermined value or more. A vapor phase epitaxial growth apparatus comprising a pressure relief valve.   2. The vapor phase epitaxial growth apparatus according to claim 1, wherein the pressure relief valve is a manometer.   3. The vapor phase epitaxial growth apparatus according to claim 1, wherein the reaction furnace, the first gas exhaust line, and the second gas exhaust line are connected by a three-way valve.   The vapor phase epitaxial growth apparatus according to any one of claims 1 to 3, further comprising a system that automatically controls opening and closing of the valve.

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