JP3242417B2 - Chamber interlock mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chamber interlock mechanism.

2. Description of the Related Art In a vertical furnace for heat-treating an object to be processed such as a semi-semiconductor wafer, a loading method as a mechanism for strictly controlling the atmosphere in which a wafer is loaded was published, for example, in March 1989. On pages 38 to 39 of the published magazine [Electronic Materials]. The load lock method disclosed herein is such that a boat vertical mechanism and the like disposed below a vertical furnace are disposed in a load lock chamber, and the inside of the chamber is evacuated, and then inert gas such as nitrogen is used. After the replacement, the boat is loaded. As a result, the wafer is prevented from being naturally oxidized during loading,
The formation of a natural oxide film is greatly suppressed.

[0002]

In the chamber as described above, the maintenance of the boat vertical mechanism and the like housed inside the chamber is performed, or the formed film adhered to the quartz jig such as the wafer boat is removed by washing. Need to open and close the chamber relatively frequently. In this case, the maintenance worker enters the chamber and carries out the work, for example, in order to carry the lowered wafer boat out of the chamber. However, as described above, nitrogen gas as an inert gas is contained inside. Is filled at normal pressure, and in the worst case, workers may be suffocated, which may cause an accident. Further, even when the worker is located in the vicinity of the opening / closing door of the chamber without entering the chamber, a large amount of nitrogen covers the worker simultaneously with opening of the opening / closing door. Has problems . In particular, the diameter of the semiconductor wafer has increased to 8 inches,
In addition, as the number of batch processes increases, the capacity of the chamber for accommodating the wafer boat also increases, and it is desired to solve the above-mentioned problems at an early stage. The present invention focuses on the above problems, and has been made to solve the problems effectively. The object of the present invention is to replace the gas in the chamber with air to reduce the oxygen concentration to a predetermined value. An object of the present invention is to provide an interlock mechanism that unlocks the maintenance door when the maintenance door is reached.

[0003]

According to the present invention, there is provided an interlock mechanism for controlling the opening and closing of a chamber filled with gas, the method comprising the steps of: detecting an oxygen concentration in the chamber; A door lock means provided in the vicinity of the maintenance door in the chamber to regulate opening and closing of the maintenance door; and releasing the door lock means when the oxygen concentration detector detects a predetermined oxygen concentration. And a door lock control means.

In a chamber filled with a gas other than oxygen, for example, nitrogen, the maintenance door is normally locked by a door lock means, and is not opened at all or only slightly opened. When performing maintenance in the chamber, the nitrogen gas in the chamber is forcibly replaced via a supply / exhaust system, or the maintenance door is slightly opened to naturally replace the nitrogen gas with external air. When the oxygen concentration detector in the chamber detects a predetermined oxygen concentration, the door lock control means releases the door lock means so that the door can be completely opened.

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a chamber interlock mechanism according to the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, a case where the present invention is applied to a vertical heat treatment apparatus will be described. As shown in FIGS. 1 to 4,
The load lock chamber 1 as a chamber filled with a gas other than oxygen, for example, nitrogen of an inert gas, is formed of, for example, stainless steel in a rectangular parallelepiped shape of, for example, 680 mm, 640 mm, and 1520 mm in height, width, and height, respectively. A vertical heat treatment apparatus 2 is provided above the load lock chamber 1. The interior of the heat treatment apparatus 2 and the interior of the load lock chamber 1 are configured to be able to communicate with each other via an upper end opening 3 of the load lock chamber. The heat treatment apparatus 2 includes, for example, an inner cylinder 4 formed of quartz in a cylindrical shape and an outer cylinder 5 of quartz concentrically surrounding the inner cylinder 4, and further includes the inner cylinder 4 and the outer cylinder 5. Is provided with a processing gas introduction pipe 7 for introducing a processing gas, an exhaust pipe 8 for removing a processed gas, a vacuum exhaust pipe 9 for evacuating the inside, and the like. In the inner cylinder 4, a quartz wafer boat 1 is provided.
A plurality of semiconductor wafers 11 stacked and mounted at a predetermined pitch in a vertical direction are accommodated in the wafer boat 10.
Is provided on a cap portion 12 for opening and closing the lower end opening of the manifold 6 via a heat retaining cylinder 13. Then, the cap portion 12, the heat retaining cylinder 13, and the wafer boat 10 are integrated with the load lock chamber 1 by a boat elevating means 15 provided in the load lock chamber 1.
The inside and the inside of the heat treatment apparatus 2 can be moved up and down.

On the other hand, one side wall of the load lock chamber 1 has a maintenance door 1 for maintaining the inside.
The maintenance door 17 is securely fixed by bolts or the like during normal operation. The interlock mechanism 20 according to the present invention is provided in the load lock chamber 1. Specifically, the interlock mechanism 20 is provided near the maintenance door 17 and an oxygen concentration detector 21 for detecting the oxygen concentration in the load lock chamber 1, and regulates the opening and closing of the maintenance door 17. Door lock means 22
And a door lock control means 24 for releasing the door lock means 22 when the detector 21 detects a predetermined oxygen concentration. The detector 21 includes:
The load lock chamber 1 is provided in an exhaust pipe 26 connected to the exhaust port 25 on the lower side wall, and is particularly installed as close to the exhaust port 25 as possible.
It is configured so that the oxygen concentration in the inside can be detected. The mounting position of the detector 21 may be provided at the bottom or the upper part in the load lock chamber 1 as a matter of course.

The output of the detector 21 is connected to the door lock control means 24. When the detected oxygen concentration becomes a predetermined value, for example, 18% or more, the door lock means 22 is opened. Is configured to obtain. The door lock means 22 includes a cylinder 30 as shown in FIG.
A piston 32 which is retracted from the cylinder 30 by compressed air or the like, and a lock pin 36 which is rotatable at the end of the piston 32 immediately in front of the maintenance door 17 via a crank 34. When the oxygen concentration in the load lock chamber 1 is low, the lock pin 36 is located immediately before the maintenance door 17 so that the door 17 is not opened. The mounting position of the door lock means 22 is not limited to immediately before the maintenance door 17, and may be slightly separated from the maintenance door 17 as shown by a chain line in FIG.
The maintenance door 17 may be provided at a position where the opening of the maintenance door 17 is stopped so that the operator's head cannot enter the load lock chamber 1 and the opening operation of the maintenance door 17 is stopped. Then, in the load lock chamber 1,
Robot chamber 4 made airtight through gate valve 40
2, a transfer device (not shown) for transferring a semiconductor wafer and a cleaning device (not shown) for removing a natural oxide film formed on the surface of the semiconductor wafer. ) Etc. are accommodated. On the side wall of the robot room 42, a plurality of observation windows 44 made of glass or the like for observing the internal operation state are formed.

A gate is provided in the robot room 42.
A cassette chamber 48, which is air-tightly connected via a valve 46, is connected to the cassette chamber 48. The cassette chamber 48 accommodates a plurality of semiconductor wafers (not shown). I have. In the load lock chamber 1, the robot chamber 42, and the cassette chamber 48, nitrogen supply pipes 54, 56, and 58 for supplying an inert gas, for example, nitrogen from a nitrogen supply source 52 are provided with valves 60 and 6, respectively.
2, 64 are connected. A clean gas supply system 80 for supplying a clean gas as necessary is connected to the nitrogen supply pipes 54, 56, 58 in parallel with the nitrogen supply source 52 via a valve 82. Similarly, exhaust pipes 26, 66, 68 for evacuating the respective chambers are connected to the respective chambers 1, 42, 48, and these exhaust pipes are provided with pressure gauges and open / close valves (shown in the figure). And a vacuum evacuation system equipped with, for example, a turbo molecular pump.

Next, the operation of this embodiment configured as described above will be described. First, at the time of normal operation, each vacuum evacuation system is operated to evacuate the inside of the reaction vessel of the heat treatment apparatus 2 and the inside of the load lock chamber 1, the robot chamber 42, and the cassette chamber 48, for example, to 10 ^-5 to 10 ^-6 Torr In this manner, gases remaining in the inside, such as water vapor and oxygen, which are a factor of forming a natural oxide film are eliminated. Then, the inside of the reaction vessel and each chamber 1, via the processing gas introduction pipe 7 and the nitrogen supply pipes 54, 56, 58.
Nitrogen gas is supplied to 42 and 48 until normal pressure is reached. Next, the cassette containing the semiconductor wafer is placed in the cassette chamber 48.
The semiconductor wafer is transferred to the wafer boat 10 which has already been lowered into the load lock chamber 1 by the transfer device provided in the robot chamber 42. At the time of transfer, the natural oxide film on the semiconductor wafer is removed by a cleaning device (not shown) in the robot chamber 42. When the transfer is completed, the wafer boat 10 is raised by the boat lifting / lowering means 15 to accommodate the semiconductor wafer in the reaction vessel, and the semiconductor wafer 11 is held for a predetermined time by a predetermined temperature, a predetermined pressure and a predetermined processing gas. Heat treatment. When the predetermined heat treatment is completed, the inside of the reaction vessel is evacuated again to remove the remaining processing gas or water vapor and oxygen components, and then the internal pressure is brought to normal pressure by introducing nitrogen gas. Then, the wafer boat 10 is lowered into the load lock chamber 1, and the processed semiconductor wafer is unloaded through the robot chamber 42 and the cassette chamber 48 in the reverse order of the loading procedure described above. Then, the next unprocessed semiconductor wafer is loaded into the cassette 48 and processed in the same procedure.

Next, a case where the inside of the load lock chamber 1 is maintained will be described. For example, when the heat treatment is performed a predetermined number of times, the load lock chamber 1 is used to remove the film adhering to the quartz jig such as the wafer boat 10 by washing or to perform maintenance and inspection of the boat elevating means 15 in the load lock chamber 1. The maintenance door 17 must be opened, but the load lock chamber 1 and the inside of the reaction vessel are filled with nitrogen at normal pressure. The gate valve 40 is closed to partition the robot chamber 42 side. First, in FIG. 2, a case where the door lock means 22 is installed at a position shown by a chain line slightly separated from the maintenance door 17 will be described. Boat lifting / lowering means 15 in load lock chamber 1
In the case of maintenance and inspection of internal equipment such as
Is housed in a reaction vessel, and the opening 3 of the manifold 6 is hermetically sealed with a cap portion 12. On the other hand, when taking out the wafer boat 10 from the load lock chamber 1 for cleaning, the wafer boat 10 is lowered into the load lock chamber 1 in advance. The oxygen concentration in the load lock chamber 1 is detected by the oxygen concentration detector 21, and the detected value is transmitted to the door lock control means 24. The control means 24 controls locking and unlocking of the door lock means 22 according to the detected oxygen concentration.

[0010] Even if the maintenance worker attempts to completely open the maintenance door 17 by removing bolts and the like for fixing the maintenance door 17, the nitrogen concentration inside is high and the oxygen concentration becomes a predetermined value, for example, the oxygen concentration in the air. If it is lower than a certain 18%, the maintenance door 17 is opened halfway, abuts on the lock pin 36 and is locked by this, and does not open any more. At this time, the opening distance L of the maintenance door 17 is set to a distance that does not allow the head of the worker to enter, for example, 10 to 15 cm.
Even if the oxygen concentration is low, it is possible to prevent the suffocation accident from entering the room too quickly and causing the accident. When the door 17 is in the half-open state, the internal nitrogen is naturally replaced with the clean air in the external clean room, and the internal oxygen concentration gradually increases. When the oxygen concentration detector 21 detects, for example, an oxygen concentration of 18% after the replacement proceeds to some extent, the door lock control means 2
4 rotates the lock pin 36 of the door lock means 22 composed of a cylinder mechanism to unlock the maintenance door 17. Then, as shown in FIG. 2, the worker can fully open the maintenance door 17, and can enter the load lock chamber 1 and perform the maintenance work under a safe atmosphere.

In particular, when the internal nitrogen is naturally replaced as described above, since the clean gas is always down-flowed in the clean room in which the heat treatment apparatus is installed, the nitrogen in the load lock chamber 1 is increased. Thus, the oxygen concentration detector 21 is installed in the lower part of the load lock chamber 1 where air replacement is slowest, whereby the safety of the worker can be further improved. Next, a case where the door lock means 22 is installed at a position shown by a solid line provided substantially in contact with the maintenance door 17 in FIG. 2 will be described. In this case, since the maintenance door 17 cannot be opened even by a small amount, the air replacement as described above cannot be performed naturally. Therefore, the forced air replacement is performed. First, a nitrogen atmosphere in the room is exhausted by a vacuum exhaust system 70 connected to the load lock chamber 1 to make the room a certain degree of vacuum. Next, while the vacuum evacuation system 70 is stopped or driven, a clean gas is introduced from the clean gas supply source 80 into the load lock chamber 1 through the supply pipe 54 to make the room normal pressure. In this process,
When the oxygen concentration detector 21 detects the oxygen concentration, for example, 18%, the lock pin 36 of the door lock means 22 is operated as described above.
Is rotated and removed from the front surface of the maintenance door 17 to release the door lock, and the operator can perform the maintenance work in a safe atmosphere by fully opening the maintenance door 17.

If the oxygen concentration still does not reach the predetermined value even when the clean gas is supplied and the pressure in the room becomes normal pressure, the evacuation operation for eliminating nitrogen is insufficient. , And further evacuate. Here, the reason for using a clean gas when performing the forced replacement is that air used in factories and the like contains dirt such as oil of a compressor, so that contamination in the apparatus due to the oil and the like is avoided. That's why. In the above embodiment, the set oxygen concentration is not limited to 18%, but may be, for example, about 10%. In any case, the oxygen concentration is set so that the worker does not choke. Note that, in the above embodiment, the present invention
The case where the present invention is applied to a heat treatment apparatus such as a D apparatus and an oxidation diffusion apparatus has been described. However, the present invention is not limited to this, and it is needless to say that any chamber that handles a gas other than oxygen can be applied.

[0013]

In summary, according to the present invention, it is possible to lock the maintenance door without completely opening the maintenance door until the gas other than oxygen in the chamber is replaced with air and the oxygen concentration reaches a predetermined value. it can. Therefore, it is possible to prevent the worker from entering the chamber even when the oxygen concentration is so low that the maintenance is urgent, so that the safety of the maintenance work can be improved.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment in which a chamber interlock mechanism according to the present invention is applied to a heat treatment apparatus.

FIG. 2 is a plan view showing a chamber used in the present invention.

FIG. 3 is a front view showing a chamber used in the present invention.

FIG. 4 is a side view showing a chamber used in the present invention.

FIG. 5 is a plan view showing a door lock means used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chamber (load lock chamber) 2 Heat treatment apparatus 17 Maintenance door 20 Interlock mechanism 21 Oxygen concentration detector 22 Door lock means 24 Door lock control means 36 Lock pin 52 Nitrogen supply source 70 Vacuum exhaust system

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/31 H01L 21/31 F

Claims (8)

(57) [Claims] 1. An interlock mechanism for controlling the opening and closing of a chamber filled with gas, comprising: an oxygen concentration detector for detecting an oxygen concentration in the chamber; A chamber interlock, comprising: door lock means for restricting opening and closing of a door; and door lock control means for releasing the door lock means when the oxygen concentration detector detects a predetermined oxygen concentration. mechanism. 2. The apparatus according to claim 2, wherein the oxygen concentration detector is provided in the chamber.
Characterized by being provided in an exhaust pipe for exhausting the atmosphere of
The chamber interlock mechanism according to claim 1. 3. The oxygen concentration detector is provided in the chamber.
2. The switch according to claim 1, wherein the switch is provided at a lower portion of the switch.
Chamber interlock mechanism. 4. The door lock means according to claim 1, wherein
The maintenance door may be slightly
To open the interior atmosphere and allow the internal atmosphere to be replaced naturally.
Being installed slightly away from the maintenance door
The channel according to any one of claims 1 to 3, wherein
Interlock mechanism of the bus. 5. An atmosphere inside the chamber is provided in the chamber.
Connect to the vacuum exhaust system and clean air supply for forced replacement.
5. The method according to claim 1, wherein the connection is continued.
An interlock mechanism for a chamber according to any one of the above. 6. The method according to claim 1, wherein the chamber is heat-treated on the semiconductor wafer.
Connected to the heat treatment device for applying
The method according to any one of claims 1 to 5, wherein
Chamber interlock mechanism. 7. The door lock control means includes:
The oxygen concentration detected by the temperature detector
Door lock when the oxygen concentration becomes
7. The method according to claim 1, wherein the locking means is released.
An interlock mechanism for the chamber according to any one of the above. 8. An oxygen concentration such that said worker does not suffocate.
Is 10% or more.
Chamber interlock mechanism.