JP2001248969A - Heat treatment system and method for operating the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment system capable of alleviating an influence of, for example, a frequent change of a flow rate of a refrigerant such as a cooling water or the like while maintaining safety high by cutting off a power supply only after a state in which the flow rate of the refrigerant is lowered to a predetermined value or less is continued for a predetermined period. SOLUTION: The heat treatment system comprises a heating means 12 for heat- treating a material W to be heat treated in a treating container 4 and cooling systems 42 to 48 for cooling constituting members 10, 12, 18, 20. Further, the system comprises flowmeters 42C to 48C for detecting flow rates of the refrigerants flowing to the cooling systems, timer means 42E to 48E for measuring times for indicating states of flow rate predetermined values or less of outputs of the flowmeters, and power cut-off relay means 42F to 48F for cutting off the power supplies to the heating means based on the outputs of the timer means. Thus, the power supply is cut off only after the state in which the flow rate of the refrigerant such as the cooling water or the like is lowered to the predetermined value or less is continued for the predetermined period. Then, an influence of the case in which the flow rate change, for example, frequently occurs while maintaining the safety high is alleviated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for performing a predetermined heat treatment on an object to be processed such as a semiconductor wafer and a method of operating the same, and more particularly to an improvement in a cooling system.

[0002]

2. Description of the Related Art Generally, in a heat treatment apparatus for producing a semiconductor integrated circuit by performing various heat treatments such as film formation, oxidation diffusion, annealing, etching and the like on an object to be processed such as a semiconductor wafer, For safety measures, various cooling systems are provided for cooling 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. It has become. In this case, while the heat treatment apparatus is operating and the heater incorporated therein is generating heat, naturally, cooling water is continuously supplied to the cooling system to cool the corresponding components. If the flow rate of the cooling water decreases or the supply of the cooling water stops due to an external factor such as a failure, the heater may run out of heat. For example, if the cooling water stops flowing due to water cutoff or the like, the cooling water in the cooling system is heated and boiled, and this pressure damages a flow meter provided in the cooling system, or steam is blown out from the cooling system. Dangerous situations may occur. 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 thermally damaged. I have.

[0003]

However, in the above-described safety measures, when the flow rate of the cooling water falls, for example, below a predetermined flow rate value during operation of the apparatus, the power supply to the heater is immediately performed. Because the supply is cut off, for example, when the flow rate of the flowing cooling water fluctuates due to pressure fluctuations due to inadequate water supply equipment or construction of water supply equipment, the flow rate is set to the lower limit. Is detected every time the temperature is reduced, and a phenomenon occurs in which the power supply to the heater is cut off. Therefore, the frequency of power cutoff increases, and the device itself may not be operated sufficiently. There was a problem. The present invention has been devised in view of the above problems and effectively solving them. An object of the present invention is to cut off the power supply only when a state in which the flow rate of a coolant such as cooling water is reduced to a predetermined value or less continues for a certain period of time. An object of the present invention is to provide a heat treatment apparatus and an operation method thereof that can reduce the influence of such a case.

[0004]

An object of the present invention is to provide a heat treatment apparatus having a heater and a cooling system for cooling constituent members in order to perform a predetermined heat treatment on an object to be processed in a processing vessel. In the device, a flow meter for detecting a flow rate of the refrigerant flowing in the cooling system, a timer means for measuring a time during which an output of the flow meter indicates a state of being equal to or less than a predetermined flow rate value, and an output of the timer means Power cut-off relay means for cutting off power supply to the heater means.
Thereby, when the flow rate of the refrigerant in the cooling system drops below a predetermined value, the timer means measures the time in the state, and when this state is continued for a predetermined time or more,
The power cut-off relay means operates to cut off the power supply to the heater means. Therefore, even if the flow rate (pressure) of the refrigerant and the supply stop frequently occur, the influence can be reduced to a minimum and the safety can be maintained at a high level.

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 at a lower portion of the processing container, A cap cooling system that cools a cap that closes a lower end opening of the processing container during heat treatment, and a top plate that is installed above the processing container and a shutter member that closes a lower end opening of the processing container instead of the cap. And at least one of a top plate and a shutter cooling system for cooling the above. Further, for example, as defined in claim 3, an alarm means for issuing an alarm when the output of the flow meter indicates a predetermined value or less of the flow rate may be provided.

Further, for example, as defined in claim 4,
A safety valve that is opened when the pressure in the cooling system becomes equal to or higher than a predetermined value may be branched and connected to the cooling system. According to this, 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 improved. Claim 5 is an invention according to the method of operating the heat treatment apparatus described above, that is, a heating heater means for performing a predetermined heat treatment on the object to be processed in the processing vessel and a cooling system for cooling the constituent members. 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 maintained at a flow rate equal to or less than a predetermined value for a predetermined time or more. Cut off the power supply.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat treatment apparatus according to the present invention and an operation method thereof will be described below in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing an example of a heat treatment apparatus according to the present invention, and FIG. 2 is a configuration diagram of a cooling system of the heat treatment apparatus shown in FIG. Here, a vertical heat treatment apparatus that can heat-treat a plurality of semiconductor wafers at a time will be described as an example of the heat treatment apparatus. As shown in the figure, the vertical heat treatment apparatus 2 has a cylindrical processing vessel 4 whose longitudinal direction is arranged substantially vertically, and the processing vessel 4 is made of a heat-resistant material such as quartz. It is mainly constituted by a cylinder 6 and an inner cylinder 8 made of, for example, quartz concentrically arranged inside the cylinder 6.
It has a heavy pipe structure. The lower end of the outer cylinder 6 and the inner cylinder 8 is 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] A cylindrical heat heater means 12 composed of, for example, a resistance heating element is disposed so as to surround the processing container 4 to constitute a heat treatment section. On the outside of the heater unit 12, there is provided a
A heat insulating layer 14 made of, for example, a silica block is formed. Outside the heat insulating layer 14, a cylindrical outer case 16 made of, for example, stainless steel for protecting the heater unit 12 so as to surround the heat insulating layer 14 is formed. Is provided. Further, on the outside thereof, a housing 1 for protecting the entire device is provided.
7 is provided, and a top plate 18 for protecting this portion is installed on the upper surface of the ceiling portion of the housing 17. Further, a disc-shaped cap portion 20 made of, for example, stainless steel or the like is attached to an opening at a lower end portion of the manifold 10 through an O-ring 22 of an elastic member so as to be hermetically sealed. A rotary shaft 24 that can rotate in a hermetically sealed state by a magnetic fluid seal, for example, is inserted through a substantially central portion of the cap portion 20. This rotating shaft 2
The lower end of the turntable 2 is connected to a rotation mechanism 26, and the upper end of the turntable 2 is made of, for example, stainless steel.
8 is fixed.

On the turntable 28,
A heat retaining cylinder 30 made of quartz is installed, and a wafer boat 32 made of, for example, quartz is placed on the heat retaining cylinder 30. A large number of wafers, for example, 50 to 1
Fifty semiconductor wafers W as objects to be processed 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 integrally loaded and unloaded into 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 lower portion of the inner cylinder 8 while controlling the flow rate. Has become.

An exhaust port 38 connected to a vacuum pump (not shown) is provided on the lower side surface of the outer cylinder 6, and the exhaust gas 38 flows down the gap between the inner cylinder 8 and the outer cylinder 6. The used gas is evacuated out of the container.
At the same horizontal level as the lower end opening of the manifold 10, a shutter member 40, for example, which can be swiveled or reciprocated, is provided to unload the wafer boat 32 from the inside of the processing container 4 downward. When the cap unit 20 is lowered by using the shutter member 40, the lower end opening of the manifold 10 is closed by the shutter member 40 instead of the cap unit 20.

[0011] Of the components of the heat treatment apparatus formed as described above, a predetermined component is provided with a cooling system for cooling it. In the present embodiment, the heater unit 12, the cap unit 20, the manifold 10,
A cooling system is provided for each component of the ceiling plate 18 and the shutter unit 40. Specifically, the heater unit 1
2, the heater cooling system 42 is provided outside the heat insulating layer 14.
However, the cap cooling system 44 is
However, the manifold 10 has a manifold cooling system 46.
A top plate / shutter cooling system 48 (see also FIG. 2) is provided for the top plate 18 and the shutter member 40 so as to communicate them in series. In this case, a passage for flowing, for example, cooling water as a coolant to each component member may be formed by forming a channel 50 in the component member, for example, stainless steel by grooving, or winding a stainless steel pipe 52, for example, outside the heat insulating layer 14. It is formed by turning. Here, as for the top plate 18 and the shutter member 40, a cooling system in which these components are connected in series was used because the temperature of both components is lower than those of the other components. However, these components may also be provided with cooling systems individually and independently.

Here, referring to FIG.
The configuration of 48 will be described. As shown in FIG. 2, both ends of each of the cooling systems 42 to 48 are respectively connected to one, so that cooling water can be introduced from one side and discharged from the other side. On both ends of each 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 each of the cooling systems 42 to 48 at the time of maintenance or the like. On-off valve 4
6A, 46B and on-off valves 48A, 48B are interposed respectively. Each of the cooling systems 42 to 48 has a flow meter 42C, 44 for measuring the flow rate of the cooling water flowing therethrough.
C, 46C, and 48C are interposed respectively, and can individually output flow rate signals. In this case, in each of the flow meters 42C to 48C, a lower limit flow value can be individually set, and when the actual flow rate becomes smaller than the lower limit flow rate value (predetermined flow rate value), the fact is output as an output signal. It is supposed to.

Further, each of the cooling systems 42 to 48 has a safety valve, such as a pressure-adjustable check valve 42, which opens when the pressure exceeds a predetermined pressure, for example, against the elastic force of an elastic spring.
D, 44D, 46D, and 48D are branched and connected, respectively, to prevent abnormal pressure rise in each of the cooling systems 42 to 48. In this case, the pressure set values of the safety valves 42D to 48D are all the same. Each of the safety valves 42A to 48D is connected to the drain passage 54, and discharges the discharged steam and the like to the outside of the system through the drain passage 54. Here, returning to FIG.
Output signals output from the respective flow meters 42C to 48C are input to power cut-off relay means provided with timer means, respectively. Specifically, an output signal from the flow meter 42C is output from a power cut-off relay 42F provided with a timer 42E.
The output signal from the flow meter 44C is output to the power cut-off relay means 44F provided with the timer means 44E, the output signal from the flow meter 46C is output to the power cut-off relay means 46F provided with the timer means 46E, and the output from the flow meter 48C. The signal is input to the power cut-off relay means 48F provided with the timer means 48E.

Each of the power cut-off relay means 42F to 4F
8F is magnetically coupled to an open / close switch 60 provided on a power line 58 connecting the heater unit 12 and a power source 56 for supplying power thereto. The open / close switch 60 is forcibly switched from the closed state to the open state when at least one of the relays operates. Here, each of the timer means 42E to 48E can set the time interval arbitrarily, and starts measuring the time when a signal equal to or less than a predetermined flow rate value (set value) is input from the corresponding flow meter. The time interval is, for example, in a range of about 30 seconds to 5 minutes, and here, for example, all are set to 1 minute. And, the state where the signal below the flow rate predetermined value is input,
When the connection is made for one minute or more, the corresponding power cutoff relay is driven. When a signal indicating that the flow rate has returned to a predetermined value or more within one minute after the start of measurement by the timer means is input, the measurement by the timer means is of course reset.

The output signals of the flow meters 42C to 48C are also input to a main controller 62 for controlling the operation of the entire heat treatment apparatus. The main control unit 62 is connected to, for example, an alarm buzzer 64A as an alarm means 64, an alarm lamp group 64B corresponding to each component, and an alarm display panel 64C, and indicates, for example, that the flow rate has become a predetermined value or less. As soon as a signal is input, the alarm display 6
4C is driven, and if it does not return to its original state, after a predetermined time, the alarm buzzer 64A is sounded and the corresponding alarm lamp group 64B is flashed to issue an alarm to the operator. Further, a thermostat 70 set at a predetermined temperature, for example, about 80 ° C., is provided inside the ceiling portion of the housing 17, and when a temperature of 80 ° C. or more is detected, a power cut-off relay means having no timer means is provided. 72A can be driven immediately.

The heat insulating layer 1 surrounding the heater means 12
4, a thermometer, for example, a thermocouple 74 is also provided.
6, another power cut-off relay without timer means 7
2B. In the cutoff temperature setting section 76,
The temperature for cutting off the power supply can be set, and can be arbitrarily changed depending on the type of heat treatment, for example, 400 ° C. to 1200 ° C. depending on the type of heat treatment here.
The temperature is set within a range of, for example, 1000 ° C. This set temperature is, for example, 50 to 100 ° C. of the planned process temperature.
Set the temperature to an additional level. The operating state of each of the power cut-off relays 42F to 48F, 72A, 72B is input to the main control unit 62, and the main control unit 62 can recognize the operating state.

Next, the operation of the present embodiment configured as described above will be described. First, when heat treatment is performed on the semiconductor wafer W, the semiconductor wafers are mounted on the wafer boat 32 in multiple stages, loaded into the pre-heated processing container 4 from below, and stored therein. The lower end opening of 10 is closed with a cap 20. Then, the semiconductor wafer W is heated to and maintained at the process temperature by the heater unit 12, and at the same time, the processing vessel 4
For example, a processing gas is introduced while evacuation is performed in accordance with a processing mode, and a predetermined heat treatment is performed on the semiconductor wafer W. At this time, in order to cool each component provided with each of the cooling systems 42 to 48, for example, cooling water is continuously supplied as a refrigerant to each of the cooling systems 42 to 48 at a flow rate corresponding to each system to maintain safety. In addition, thermal damage to components and the like is prevented. 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 predetermined individual flow rates to cool the corresponding components.

Here, the flow rate of the cooling water flowing through each of the cooling systems 42 to 48 is constantly monitored by flow meters 42C to 48C provided respectively. The flow rate set value (flow rate predetermined value) individually set in each of the flow meters 42C to 48C due to the interruption of the cooling water or the fluctuation of the supply pressure.
If the following is true, the corresponding power interruption relay means 4
It is transmitted to the 2F to 48F side. Then, the corresponding timer means 42E to 48E are operated to start measuring the time during which the flow rate is equal to or less than the set value. Here, for example, one minute is set in advance as the grace time, and when the state below the flow rate set value as described above continues for one minute or more, the corresponding power cut-off relay means is recognized only when it is recognized that the above has occurred. In operation, the open / close switch 60 provided on the power line 58 is opened by electromagnetic force, and the power supply to the heater unit 12 is cut off. The main control unit 6
In No. 2, the subsequent heat treatment is stopped assuming that an abnormality has occurred.

Therefore, for some reason, for example, the supply of the cooling water is temporarily stopped, for example, for about 10 seconds, and then immediately returns to the normal state. For example, when the supply pressure is reduced by about 20 seconds and the flow rate is reduced below the flow rate set value and returned after 20 seconds, the power supply is not cut off and the heat treatment apparatus is operated stably. Becomes possible. In this way, even if the short-time water interruption or pressure fluctuation that does not affect the safety occurs, the heat treatment apparatus can be operated stably without being affected by the water interruption, and the water interruption can be performed for a predetermined time or more. When such a situation occurs, the power supply to the heater unit 12 can be cut off as before, so that the safety can be maintained as high as before.

An alarm means 64 for issuing an alarm to the operator.
Can take various modes of operation. For example, if one minute is allowed until the power supply is cut off as described above,
For the first 30 seconds, only the alarm display board 64C is displayed, and for the remaining 30 seconds, in addition to the display of the alarm display board 64C, the alarm buzzer 64A sounds and the corresponding lamp in the alarm lamp group 64B flashes. What should be done is. If the flow rate of the cooling water is restored within one minute, all the alarm operations are stopped at that time. Here, even if the flow rate of the cooling water falls below a predetermined value, or the supply of the cooling water is stopped, the power supply to the heater unit 12 is cut off. Since a large amount of heat is accumulated and remains in the portion centered at 4, the cooling water is heated and boiled by the residual heat, and the pressure in each of the cooling systems 42 to 48 rises sharply and the flow meters 42C to 42C. 48C or the like may be damaged.

However, in this embodiment, the safety valves 42D to 48D are branched and connected to the respective cooling systems 42 to 48, so that when a pressure exceeding a set value is generated, the safety valves are opened. The pressure acts to release the pressure, so that the safety can be improved accordingly. 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 set at a process temperature or slightly lower than the processing temperature in preparation for the next heat treatment. The temperature is maintained at a low level. During this time, the lower end opening of the manifold 46 is closed by the shutter member 40 instead of the cap 20. The shutter member 40 is connected to the top plate and the top plate that operate as described above.
It is cooled by a shutter cooling system 48.

When the thermostat 70 installed inside the ceiling portion of the housing 17 operates at a predetermined temperature value, for example, 100 ° C. or higher in this portion, or when a thermocouple provided on the heat insulating layer 14 is operated. When the temperature of the heater 74 becomes a predetermined temperature value set in advance in this portion, for example, 1000 ° C. or more, the power cut-off relay means 72A or 72B corresponding to each of the timers, which are not provided with the timer means, is immediately operated, and the heating is stopped. Since the power supply to the heater means 12 is immediately shut off, safety can be ensured. Here, timer means 42 are provided in all four cooling systems 42 to 48.
Although the case where E to 48E is provided has been described as an example, the present invention is not limited to this, and a timer means may be provided in at least one cooling system.

Further, the number of components provided with the cooling system is not limited to the four in the present embodiment, and any component requiring cooling can be applied. Furthermore, although the present invention has been described by taking a vertical batch type heat treatment apparatus as an example, any apparatus using a cooling system such as a horizontal batch type heat treatment apparatus or a single-wafer type heat treatment apparatus can be applied. Of course you can. In addition, although a semiconductor wafer has been described as an example of the object to be processed, the present invention is not limited to this, and can be applied to an LCD substrate, a glass substrate, and the like.

[0024]

As described above, according to the heat treatment apparatus and its operation method of the present invention, the following excellent operational effects can be exhibited. According to the inventions 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 in which the state has been reached, and this state is determined. When a predetermined time or more has elapsed, the power cut-off relay means operates to cut off the power supply to the heater means. Therefore, even if the flow rate (pressure) of the refrigerant fluctuates frequently or the supply stops, the effects can be reduced to a 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 improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of a heat treatment apparatus according to the present invention.

FIG. 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 Heater means 18 Top plate 20 Cap part 32 Wafer boat 40 Shutter member 42-48 Cooling system 42C-48C Flow meter 42D-48D Safety valve 42E-48E Timer means 42F-48F, 72A, 72B Power cut-off relay means W Semiconductor wafer (workpiece)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01L 21/22 511 H01L 21/22 511A 21/324 21/324 G F term (reference) 4K056 AA09 BA01 BB06 CA18 FA01 FA02 4K061 AA01 AA05 BA11 CA08 CA13 CA19 DA05 GA01 GA02 5F045 BB20 DP19 EJ09 EK06 GB04 GB15

Claims (5)

[Claims] In a heat treatment apparatus having a heater unit and a cooling system for cooling constituent members for performing a predetermined heat treatment on an object to be processed in a processing container, a flow rate of a refrigerant flowing through the cooling system is detected. A flow meter, a timer means for measuring a time during which the output of the flow meter indicates a state of a flow rate equal to or less than a predetermined value, and a power cut-off relay for interrupting power supply to the heater based on the output of the timer means. And a heat treatment apparatus. 2. The cooling system according to claim 1, wherein the cooling system includes a heater cooling system configured to cool the heater unit, a manifold cooling system configured to cool a manifold provided at a lower portion of the processing container, and a lower end opening of the processing container closed during heat treatment. A cap cooling system for cooling the cap portion, a top plate provided above the processing container, and a top plate for cooling a shutter member for closing a lower end opening of the processing container instead of the cap portion.
2. The heat treatment apparatus according to claim 1, wherein the heat treatment apparatus is at least one of a shutter cooling system. 3. The heat treatment apparatus according to claim 1, further comprising an alarm unit that issues an alarm when the output of the flow meter indicates a predetermined value or less of the flow rate. 4. The cooling system according to claim 1, wherein a safety valve that is opened when a pressure in the cooling system becomes equal to or higher than a predetermined value is branched and connected to the cooling system. 3. The heat treatment apparatus according to item 1. 5. A method of operating a heat treatment apparatus having a heater unit and a cooling system for cooling constituent members in order to perform a predetermined heat treatment on an object to be processed in a processing container. Detecting a flow rate, and stopping the power supply to the heater means in response to maintaining the state where the detected value is equal to or less than a predetermined flow rate for a predetermined time or more. Operation method.