JP4207354B2 - Heat treatment apparatus and operation method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment apparatus that performs a predetermined heat treatment on an object to be processed such as a semiconductor wafer and an operation method thereof, and more particularly, to an improvement in a cooling system.
[0002]
[Prior art]
In general, in a heat treatment apparatus for manufacturing a semiconductor integrated circuit by performing various heat treatments such as film formation, oxidation diffusion, annealing, etching, etc. on an object to be processed such as a semiconductor wafer, Various cooling systems are provided in order to cool various components to a predetermined temperature or lower, and the corresponding components are cooled by flowing, for example, cooling water as a coolant through the cooling system.
In this case, while the heat treatment apparatus is in operation and the heater built in it is generating heat, it is a matter of course that the cooling water is continuously supplied to the cooling system to cool the corresponding components. If the flow rate of the cooling water decreases due to an external factor such as a failure or the supply of the cooling water is stopped, the heater may run out of heat. For example, if water breakage occurs and the cooling water does not flow, the cooling water in the cooling system will boil with heating, the flow meter provided in the cooling system will be damaged by this pressure, or steam will blow out from the cooling system, etc. There is a risk of unsafe conditions.
For this reason, as a safety measure, when the flow rate of the cooling water falls below a certain value, the power supply to the heater is automatically cut off to prevent the heat treatment apparatus from being damaged in advance. Yes.
[0003]
[Problems to be solved by the invention]
By the way, in the safety measures as described above, the power supply to the heater is cut off immediately when the flow rate of the cooling water becomes, for example, a predetermined flow rate value or less during operation of the apparatus. For example, if the flow rate of the cooling water that is flowing due to inadequate water supply facilities or due to construction of the water supply facility causes the flow rate to fluctuate, this is detected each time the flow rate drops to the lower limit. The phenomenon that the power supply to the heater is interrupted occurs, and therefore, the frequency of power interruption increases, and there is a problem that the apparatus itself cannot be fully operated.
The present invention has been devised to pay attention to the above-described problems and effectively solve them. An object of the present invention is to shut off the power supply for the first time when the flow rate of the coolant such as cooling water has been reduced to a predetermined value or lower for a certain period of time. It is an object of the present invention to provide a heat treatment apparatus and an operation method thereof that can reduce the influence in the case where the problem occurs.
[0004]
[Means for Solving the Problems]
The invention defined in claim 1 is a heat treatment apparatus having a heater unit and a cooling system for cooling a constituent member in order to perform a predetermined heat treatment on an object to be processed in a processing container. of a flow meter for detecting the flow rate, and timer means for measuring a while when the output of the flow meter is continuously maintained following state flow predetermined value, to the heater means based on an output of said timer means Power cutoff relay means for cutting off power supply.
As a result, when the flow rate of the coolant in the cooling system drops below a predetermined value, the timer means measures the time during which it is in that state, and the power cut-off relay means operates when this state continues for a predetermined time or more. Thus, power supply to the heater means is cut off. Therefore, even if the refrigerant flow rate (pressure) fluctuates and the supply stops frequently, the influence can be reduced to the minimum and the safety can be maintained high.
[0005]
In this case, for example, as defined in claim 2, the cooling system includes a heater cooling system for cooling the heater means, a manifold cooling system for cooling a manifold provided in a lower portion of the processing container, and the processing container. A cap cooling system that cools the cap portion that closes the lower end opening of the processing vessel, a top plate disposed above the processing vessel, and a shutter member that closes the lower end opening of the processing vessel instead of the cap portion. At least one of the top plate and shutter cooling system. Further, for example, as defined in claim 3, there may be provided alarm means for issuing an alarm in response to the output of the flow meter indicating a predetermined flow rate or less.
[0006]
Further, for example, as defined in claim 4, a safety valve that is opened when the pressure in the cooling system becomes a predetermined value or more may be branched and connected to the cooling system.
According to this, even if the refrigerant rises in the cooling system due to boiling or the like, the pressure can be released from the safety valve, and the safety can be improved.
Claim 5 is an invention relating to the operation method of the heat treatment apparatus described above, that is, a heater system and a cooling system for cooling the constituent members in order to perform a predetermined heat treatment on the object to be processed in the processing container. In the operation method of the heat treatment apparatus, the flow rate of the refrigerant flowing through the cooling system is detected, and the detected value is supplied to the heater means in response to maintaining the state where the detected value is equal to or lower than the predetermined flow rate for a predetermined time or longer. Try to cut off the power supply.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a heat treatment apparatus and its operation method according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing an example of a heat treatment apparatus according to the present invention, and FIG. 2 is a block diagram of a cooling system of the heat treatment apparatus shown in FIG. Here, as a heat treatment apparatus, a vertical heat treatment apparatus capable of heat treating a plurality of semiconductor wafers at a time will be described as an example.
As shown in the figure, this vertical heat treatment apparatus 2 has a cylindrical processing container 4 whose longitudinal direction is arranged substantially vertically, and this processing container 4 is made of a heat-resistant material such as quartz. The tube 6 and the inner tube 8 made of, for example, quartz arranged concentrically on the inner side mainly constitute a double tube structure.
The lower ends of the outer cylinder 6 and the inner cylinder 8 are held by a manifold 10 made of stainless steel or the like, and the manifold 10 is fixed to a base plate (not shown).
[0008]
And the cylindrical heater means 12 which consists of resistance heating bodies, for example is arrange | positioned so that the said process container 4 may be enclosed, and the heat processing part is comprised. A heat insulating layer 14 made of, for example, a silica block for keeping the heat treatment portion is formed outside the heater means 12, and a heater means surrounding the heat insulating layer 14 is formed outside the heat insulating layer 14. A cylindrical outer case 16 made of, for example, stainless steel is provided to protect the body 12. Further, a casing 17 that protects the entire apparatus is provided on the outside thereof, and a top plate 18 for protecting this portion is installed on the upper surface of the ceiling portion of the casing 17.
In addition, a disc-shaped cap portion 20 made of, for example, stainless steel or the like is attached to an opening at the lower end portion of the manifold 10 through an O-ring 22 that is an elastic member so as to be hermetically sealed. A rotating shaft 24 that is rotatable in an airtight state by a magnetic fluid seal, for example, is inserted through a substantially central portion of the cap portion 20. The lower end of the rotating shaft 24 is connected to a rotating mechanism 26, and a turntable 28 made of, for example, stainless steel is fixed to the upper end of the rotating shaft 24.
[0009]
A heat insulating cylinder 30 made of quartz is installed on the turntable 28, and a wafer boat 32 made of, for example, quartz is placed on the heat insulating cylinder 30. In this wafer boat 32, a large number of, for example, 50 to 150 semiconductor wafers W as processing objects are accommodated at a predetermined pitch. The wafer boat 32, the heat retaining cylinder 30, the turntable 28, and the cap unit 20 are configured to be loaded and unloaded integrally in the processing container 4 by an elevating mechanism, for example, a boat elevator 34.
A processing gas introduction pipe 36 made of, for example, quartz is provided below the manifold 10 so as to penetrate the manifold 10 so that the processing gas can be introduced into the inner cylinder 8 while controlling the flow rate. It has become.
[0010]
An exhaust port 38 connected to a vacuum pump (not shown) is provided on the lower side surface of the outer cylinder 6 so that the treated gas flowing down the gap between the inner cylinder 8 and the outer cylinder 6 is removed. It is designed to evacuate out of the container.
Further, at the same horizontal level as the lower end opening of the manifold 10, for example, a shutter member 40 that can be swung or reciprocated is provided, and the wafer boat 32 is unloaded downward from the processing container 4. When the cap portion 20 is lowered, the lower end opening of the manifold 10 is closed by the shutter member 40 instead of the cap portion 20.
[0011]
And among the structural members of the heat treatment apparatus formed as described above, a predetermined structural member is provided with a cooling system for cooling it. In this embodiment, a cooling system is provided for each component of the heater means 12, the cap part 20, the manifold 10, the ceiling plate 18, and the shutter part 40. Specifically, a heater cooling system 42 is provided outside the heat insulating layer 14 for the heater means 12, a cap cooling system 44 is provided for the cap portion 20, and a manifold cooling system 46 is provided for the manifold 10. However, the top plate 18 and the shutter member 40 are each provided with a top plate / shutter cooling system 48 (see also FIG. 2) so as to communicate with each other in series. In this case, the passages through which, for example, cooling water as a refrigerant flows through the respective constituent members are formed by forming grooves 50 in the constituent members such as stainless steel, or by winding the stainless pipe 52 around the heat insulating layer 14, for example. It is formed by turning. Here, regarding the top plate 18 and the shutter member 40, a cooling system in which these are connected in series is used, because the temperature of both constituent members is lower than that of the other constituent members. However, a cooling system may be provided for each of these components.
[0012]
Here, with reference to FIG. 2, the structure of each cooling system 42-48 is demonstrated. As shown in FIG. 2, both ends of each of the cooling systems 42 to 48 are joined together, so that cooling water can be introduced from one side and cooling water can be discharged from the other side. On both ends of the cooling systems 42 to 48, that is, on the upstream side and the downstream side, for example, on-off valves 42A and 42B and on-off valves 44A and 44B for individually partitioning the cooling systems 42 to 48 at the time of maintenance, etc. On-off valves 46A and 46B and on-off valves 48A and 48B are interposed, respectively.
In addition, each of the cooling systems 42 to 48 is provided with a flow meter 42C, 44C, 46C, 48C for measuring the flow rate of the cooling water flowing through the cooling systems 42-48, respectively, so that a flow rate signal can be individually output. It has become. In this case, each of the flow meters 42C to 48C can individually set a lower limit flow rate value, and when the actual flow rate becomes smaller than the lower limit flow rate value (predetermined flow rate value), that fact is output as an output signal. It is supposed to be.
[0013]
Further, each of the cooling systems 42 to 48 includes, for example, a safety valve that opens the valve body against the elastic force of the elastic spring when the pressure exceeds a predetermined pressure, for example, pressure adjustable check valves 42D, 44D, 46D, 48D is branched and connected, and an abnormal pressure rise in each cooling system 42 to 48 is prevented. In this case, the pressure setting values of the safety valves 42D to 48D are all the same. And each safety valve 42A-48D is connected to the drain channel | path 54, The discharged | emitted vapor | steam etc. are discharged | emitted out of the system through this drain channel | path 54. FIG.
Returning to FIG. 1, the output signals output from the flow meters 42C to 48C are respectively input to the power cut-off relay means provided with the timer means. Specifically, the output signal from the flow meter 42C is supplied to the power cutoff relay means 42F provided with the timer means 42E, and the output signal from the flow meter 44C is supplied to the power cutoff relay means 44F provided with the timer means 44E. Is output to the power cutoff relay means 46F provided with the timer means 46E, and the output signal from the flowmeter 48C is input to the power cutoff relay means 48F provided with the timer means 48E.
[0014]
Each power cut-off relay means 42F to 48F is magnetically coupled to an opening / closing switch 60 provided in a power line 58 that connects the heater means 12 and a power source 56 that supplies power to the heater means 12. The on / off switch 60 is forcibly switched from the closed state to the open state when at least one of the power cut-off relay means 42F to 48F operates. Here, each of the timer means 42E to 48E can arbitrarily set the time interval, and starts measuring the time when a signal less than a predetermined flow rate (set value) is input from the corresponding flow meter. The time interval is, for example, within a range of about 30 seconds to 5 minutes, and is set to 1 minute, for example. Then, the state entered the flow predetermined value following signals, sometimes continued on more than one minute, the power cutoff relay corresponding thereto is adapted to drive. Of course, when a signal indicating that the flow rate has returned to a predetermined value or more within one minute after the timer means starts measurement, the measurement of the timer means is reset.
[0015]
The output signals of the flow meters 42C to 48C are also input to the main control unit 62 that controls the operation of the entire heat treatment apparatus. The main control unit 62 is connected to, for example, an alarm buzzer 64A, an alarm lamp group 64B corresponding to each component, and an alarm display plate 64C as the alarm means 64, and indicates that, for example, the flow rate has become a predetermined value or less. When the signal is input, the alarm display board 64C is immediately driven, and if it does not return to the original state, the alarm buzzer 64A is sounded after a predetermined time, and the corresponding alarm lamp group 64B is flashed. A warning is issued.
Further, a thermostat 70 set to a predetermined temperature, for example, about 80 ° C., is provided inside the ceiling portion of the casing 17, and when detecting a temperature of 80 ° C. or higher, a power cut-off relay means having no timer means 72A can be driven immediately.
[0016]
The heat insulating layer 14 surrounding the heater means 12 is also provided with a temperature meter, for example, a thermocouple 74, and the output of the thermocouple 74 does not have a timer means via the shut-off temperature setting unit 76 on the way. The other power cut-off relay 72B is input. The shut-off temperature setting unit 76 can set a temperature for shutting off the power supply, and can be arbitrarily changed depending on, for example, the type of heat treatment. For example, here, the range is 400 ° C. to 1200 ° C. depending on the type of heat treatment. Of these, for example, it is set to 1000 ° C. This set temperature is set to a temperature that is, for example, about 50 to 100 ° C. higher than the scheduled process temperature.
The operating states of the power cut-off relays 42F to 48F, 72A, 72B are input to the main control unit 62, and the main control unit 62 can recognize the operating states.
[0017]
Next, the operation of the present embodiment configured as described above will be described.
First, when the heat treatment is performed on the semiconductor wafer W, the semiconductor wafers are placed in multiple stages on the wafer boat 32, loaded into the pre-heated processing container 4 from below, and accommodated. The lower end opening 10 is sealed by the cap 20. Then, the temperature of the semiconductor wafer W is raised to the process temperature by the heater 12 and maintained. At the same time, the processing gas is introduced into the processing chamber 4 while evacuating the processing chamber 4 according to the processing mode. On the other hand, a predetermined heat treatment is performed. At this time, in order to cool the respective components provided with the respective cooling systems 42 to 48, for example, cooling water is continuously supplied to each of the cooling systems 42 to 48 as a coolant at a flow rate corresponding to each system to maintain safety. Prevents thermal damage of components and the like. That is, cooling water is supplied to the heater cooling system 42, the cap cooling system 44, the manifold cooling system 46, and the top plate / shutter cooling system 48 at respective predetermined flow rates to cool the corresponding components.
[0018]
Here, the flow rate of the cooling water flowing through each of the cooling systems 42 to 48 is constantly monitored by the flow meters 42C to 48C provided respectively. And if it becomes below the flow set value (predetermined flow rate) set independently in each flow meter 42C-48C due to the water cutoff of the cooling water, the supply pressure fluctuation, etc., the corresponding power cut-off relay It is transmitted to the means 42F-48F side. Then, the corresponding timer means 42E-48E operate | move and the measurement of the time which has been in the state below a flow volume setting value is started. Here, the grace has set for example in advance for 1 minute as the time, when the above-mentioned such flow setpoint following state continues for one minute or more, to recognize that an abnormality has occurred for the first time corresponding power breaker relay means Is operated, and the opening / closing switch 60 provided in the power line 58 is opened by electromagnetic force, and the power supply to the heater means 12 is cut off. Note that the main control unit 62 stops the subsequent heat treatment because an abnormality has occurred.
[0019]
Therefore, for some reason, for example, the supply of cooling water is temporarily stopped, for example, stopped for about 10 seconds, and immediately recovered, or the supply pressure of the cooling water fluctuates due to defective water supply facilities, for example, 20 When the supply pressure drops for about a second and the flow rate decreases below the flow rate set value and returns after 20 seconds, the power supply is not shut off and the heat treatment apparatus can be operated stably. Become.
In this way, even if a short-time water shutoff or pressure fluctuation that does not affect safety occurs, the heat treatment apparatus can be operated stably without being affected by these, and the water shutoff over a predetermined time or more. When the above occurs, the power supply to the heater means 12 can be cut off as usual, so that the safety can be kept high as before.
[0020]
In addition, the alarm means 64 that issues an alarm to the operator can take various modes of operation. For example, when the power supply is interrupted for 1 minute as described above, an alarm display is displayed for the first 30 seconds. It is only necessary to display the plate 64C, and for the remaining 30 seconds, in addition to the display of the alarm display plate 64C, the alarm buzzer 64A is sounded and the corresponding lamp in the alarm lamp group 64B is blinked. Of course, if the flow rate of the cooling water returns within one minute, all alarm operations are stopped at that time.
Here, even if the flow rate of the cooling water drops below a predetermined value or the supply of the cooling water is stopped, the power supply to the heater means 12 is interrupted. Since a large amount of heat is accumulated and remains in the portion centering on 4, the cooling water is heated and boiled by this residual heat, and the pressure in each of the cooling systems 42 to 48 rises abruptly and the flow meters 42C to 42C There is a risk of damage such as 48C.
[0021]
However, in the case of this embodiment, the safety valves 42D to 48D are branched and connected to the cooling systems 42 to 48, respectively, so that when the pressure higher than the set value is generated, the safety valve is opened and the pressure is increased. Since it acts so as to escape, the safety can be increased accordingly.
Further, after the heat treatment, the wafer W is lowered below the processing container 4 to be in an unloaded state. At this time, the processing container 4 is generally at a process temperature or a little lower than this in preparation for the next heat treatment. During this time, the lower end opening of the manifold 46 is closed by the shutter member 40 instead of the cap portion 20. The shutter member 40 is cooled by the top / shutter cooling system 48 that operates as described above.
[0022]
In addition, when the thermostat 70 installed inside the ceiling portion of the casing 17 operates at a predetermined temperature value set in advance in this portion, for example, 100 ° C. or more, or the thermocouple 74 provided in the heat insulating layer 14 is When a predetermined temperature value set in advance in this part, for example, 1000 ° C. or more, the power cut-off relay means 72A or 72B corresponding to each of the timer means not arranged in parallel operates immediately, and the heater means 12 The power supply to the power supply is immediately cut off, and safety can be ensured.
Here, the case where the timer means 42E to 48E are provided in all the four cooling systems 42 to 48 has been described as an example. However, the present invention is not limited to this, and the timer means may be provided in at least one cooling system. .
[0023]
Further, the number of constituent members provided with the cooling system is not limited to the four in the present embodiment, and any constituent member that requires cooling can be applied. Furthermore, although the present invention has been described here by taking a vertical batch heat treatment apparatus as an example, the present invention can be applied to any apparatus using a cooling system, such as a horizontal batch heat treatment apparatus or a single wafer heat treatment apparatus. Of course you can. Although the semiconductor wafer is described as an example of the object to be processed here, the present invention is not limited to this, and the present invention can also be applied to an LCD substrate, a glass substrate, and the like.
[0024]
【The invention's effect】
As described above, according to the heat treatment apparatus and the operation method of the present invention, the following excellent operational effects can be exhibited.
According to the invention defined in claims 1 to 3 and claim 5, when the flow rate of the refrigerant in the cooling system falls below a predetermined value, the timer means measures the time during which it is in that state, and this state is When the power interruption relay means is operated for a predetermined time or longer, the power supply to the heater means can be cut off.
Therefore, even if the refrigerant flow rate (pressure) fluctuates and the supply stops frequently, the influence can be reduced to the minimum and the safety can be kept high.
According to the invention defined in claim 4, even if the pressure rises due to boiling of the refrigerant in the cooling system, the pressure can be released from the safety valve, and the safety can be enhanced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an example of a heat treatment apparatus according to the present invention.
2 is a configuration diagram of a cooling system of the heat treatment apparatus shown in FIG.
[Explanation of symbols]
2 Heat treatment apparatus 4 Processing vessel 10 Manifold 12 Heating heater means 18 Top plate 20 Cap section 32 Wafer boat 40 Shutter members 42 to 48 Cooling systems 42C to 48C Flowmeters 42D to 48D Safety valves 42E to 48E Timer means 42F to 48F, 72A, 72B Power interruption relay means W Semiconductor wafer (object to be processed)

Claims (5)

In a heat treatment apparatus having a heater system and a cooling system for cooling the constituent members in order to perform a predetermined heat treatment on the object to be processed in the processing container, a flow meter for detecting a flow rate of the refrigerant flowing in the cooling system; and timer means for measuring a while when the output of the flow meter is continuously maintained following state flow predetermined value, and the power cutoff relay means to break the power supply to the heater means based on an output of said timer means A heat treatment apparatus comprising:   The cooling system cools a heater cooling system that cools the heater means, a manifold cooling system that cools a manifold provided in a lower portion of the processing vessel, and a cap that closes a lower end opening of the processing vessel during heat treatment. At least one of a cap cooling system and a top plate / shutter cooling system that cools a top plate installed above the processing vessel and a shutter member that closes a lower end opening of the processing vessel instead of the cap portion. The heat treatment apparatus according to claim 1, wherein the number is one.   3. The heat treatment apparatus according to claim 1, further comprising alarm means for issuing an alarm in response to an output of the flow meter indicating a predetermined flow rate or less. Wherein the cooling system, to claims 1 to 3, whichever is one wherein a safety valve to be opened, characterized in that it is connected with the branch when the pressure in the cooling system is equal to or greater than a predetermined value The heat treatment apparatus as described.   In a method for operating a heat treatment apparatus having a heater system and a cooling system for cooling constituent members in order to perform a predetermined heat treatment on the object to be processed in the processing container, the flow rate of the refrigerant flowing in the cooling system is detected, A method for operating a heat treatment apparatus, wherein the power supply to the heater means is cut off in response to maintaining the detected value at or below a predetermined flow rate for a predetermined time or longer.

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