JPH0663379A - Vacuum storehouse - Google Patents

Abstract

PURPOSE:To efficiently remove the carbonaceous org. contaminant depositing on the material stored in the vacuum storehouse by providing an UV lamp in the storehouse to irradiate the material with UV. CONSTITUTION:An UV lamp 4 is provided in a vacuum storehouse 1 for a material 2 to irradiate the material 2 with UV. A device 50 is furnished to supply a cleaning gas consisting of any of air, oxygen and ozone to the chamber provided with the UV lamp 4. The oxygen in air is irradiated with UV to generate nascent oxygen. The nascent oxygen is firmly joined to the org. matter which is decomposed and removed. Consequently, a carbonaceous org. contaminant film depositing on the material such as a wafer, glass substrate, etc., in the storehouse is efficiently removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum storage, and more particularly to a vacuum storage capable of removing organic substances adhering to a storage such as a wafer or a glass substrate during vacuum storage.

[0002]

2. Description of the Related Art In a vacuum, there is no air flow or very little air flow. Therefore, fine particles adhering to the wall of a vacuum container are peeled off or particles on the floor are lifted up. There is nothing like that. Therefore, since it is possible to create a Class 0 (zero) space in a vacuum, not only the semiconductor manufacturing process in recent years, but also the storage of stored materials such as glass substrates for making wafers and liquid crystal panels in a vacuum. Tend to do.

[0003]

However, although there is a possibility that a class 0 space can be created in a vacuum,
It is known that the vapor of oil used in a vacuum pump causes organic matter contamination by carbon (C) molecules. In a vacuum, there are two environments that are extremely good for stored items such as wafers and glass substrates, that is, the above-mentioned particle contamination does not occur, and the growth of the natural oxide film does not occur or can be suppressed significantly. However, the problem of organic matter contamination by the above-mentioned C-based molecules remains.

In order to take advantage of the above two major advantages in a vacuum environment, it is necessary to take measures against C-based organic matter contamination by the vapor of oil used in a vacuum pump. As a method therefor, firstly, there is a method of eliminating the vapor of the oil of the vacuum pump, and secondly, there is a method of removing the attached C-based organic matter from the wafer or the glass substrate immediately before the end of the storage. Although various measures have been taken for the above first method and they have been effective to some extent, C-based organic matter contamination is a problem at the molecular level, and it is difficult to completely eliminate this contamination. Is the reality.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a vacuum storage cabinet capable of effectively removing contaminants composed of C-based organic substances attached to a vacuum-stored storage material. To aim.

[0006]

The vacuum storage of the present invention for achieving the above-mentioned object is provided in the vacuum storage chamber for storing the storage product, the vacuum storage chamber or a chamber in the vicinity thereof. And an ultraviolet lamp for irradiating ultraviolet rays.

The vacuum storage is further provided with a supply device for supplying a cleaning gas of at least one of air, oxygen and ozone to the chamber provided with the ultraviolet lamp.

[0008]

In the present invention, carbon-based (C-based) organic substances are stored in the vacuum storage and are immediately exposed to ultraviolet rays, air, oxygen (O ₂ ) and ozone (O ₃ ) immediately after the storage. ), And is removed in combination with any of the above gases.

Oxygen in the air produces oxygen as a generating group by irradiation with ultraviolet rays. Since the oxygen of this generating group has a strong binding force, it binds with an organic substance containing carbon (C), hydrogen (H), and oxygen (O) to form carbon dioxide (CO ₂ ) and water (H ₂ O).
And decomposes and removes organic substances. The vacuum storage of the present invention applies this principle, and can remove the contaminated film of C-based organic matter generated during vacuum storage.

[0010]

Embodiments of the vacuum storage according to the present invention will be described below with reference to FIGS. FIG. 1 is a flow sheet showing a vacuum storage according to the first embodiment of the present invention, the vacuum storage showing an elevation. As shown in the figure, the vacuum storage 1 temporarily stores a wafer as a storage 2, or a glass substrate for making a liquid crystal panel, and can be loaded and unloaded through a door 3 that can be opened and closed. There is. Inside the vacuum storage 1, a plurality of ultraviolet lamps 4 for uniformly irradiating the surface of the wafer or the glass substrate with the ultraviolet rays are arranged. The ultraviolet lamp 4 may be any lamp that emits ultraviolet light, such as a low pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, and a deuterium lamp. Normally, a low-pressure mercury lamp of synthetic quartz is used, and in this case, it is possible to take out an ultraviolet ray having a wavelength of 184.9 nm. The ultraviolet ray having this wavelength converts oxygen (O ₂ ) into ozone (O ₃ ). Can be changed and O ₃ can be stored 2
It is effective for ashing organic substances attached to.

In the vacuum storage 1 of the above-mentioned type, one or several storages 2 are stored side by side according to the size of the storage 1 without stacking them horizontally. Also, the valve V
_The vacuum storage 1 is brought into a vacuum state from atmospheric pressure by a vacuum pump 7 communicating with the vacuum storage 1 via a pipe 6 provided with ₃ .

[0012] from the supply unit 8 is supplied with air or O ₂ through the filter 9, also O ₃ from an ozone generator 10
Is supplied and passes through the filter 9. The air from which foreign substances have been removed by the filter 9 and the cleaning gas of at least one of O ₂ and O ₃ is introduced into the vacuum storage 1 after passing through the pipe 11 and the valve V ₁ . The supply unit 8, the ozone generator 10, the filter 9, and the valve V ₁ constitute a supply device 50 for supplying the cleaning gas. Further, air or nitrogen (N ₂ ) is supplied from the supply unit 13, foreign matter is removed by the filter 14, and then it is introduced into the vacuum storage 1 after passing through the pipe 15 and the valve V ₂ .

The gas inside the vacuum storage 1 is connected to the pipe 17,
After passing through the valve V ₄ , it is treated by an exhaust gas treatment device 19 equipped with activated carbon for ozone treatment, and discharged outside the system by an exhaust gas vacuum pump 20.

Next, an operation procedure of the vacuum storage having the above configuration will be described. First, a storage item 2 such as a wafer or a glass substrate is stored in the vacuum storage 1, and then the valves V ₁ , V ₂ ,
After closing V ₄ , the vacuum pump 7 is driven and the valve V ₃ is opened to evacuate the inside of the vacuum storage 1. The storage item 2 is stored for a predetermined time while maintaining a predetermined degree of vacuum. Then, when the storage is completed, the valve V ₃ is closed, the valve V ₂ is opened, and clean air or N ₂ is supplied from the supply unit 13 to bring the internal pressure of the vacuum storage 1 to the atmospheric pressure and then the valve V ₂ . After closing, the ultraviolet lamp 4 is turned on to irradiate the storage item 2 with ultraviolet rays. Then valve V
While opening ₄ , the exhaust gas vacuum pump 20 is driven to start discharging the gas in the vacuum storage 1. Then, the valve V ₁ is opened to supply the cleaning air or O ₂ from the supply unit 8 to the storage case 1, or the ozone generator 10 supplies the cleaning O ₃ to the storage case 1. These cleaning gases are continuously flowed at a predetermined flow rate for a predetermined time. In this case, a flow rate of 10 L (liter) / min and a time of 20 to 30 minutes are sufficient. The above-mentioned air is supplied to the supply units 8 and 13.
In the case of feeding from the above, a compressor (not shown) may be used, but suction may be performed by the vacuum pump 7 or 20. The cleanliness of air, O ₂ and O ₃ is preferably 0.1 μm and class 10 or less. Thus, by feeding the cleaning gas into the vacuum storage 1 to fill the inside of the storage chamber 1 with the cleaning gas and irradiate the stored material 2 with ultraviolet rays, the organic substances attached to the stored material 2 during vacuum storage are removed. It will be removed and washed. When this cleaning is completed, the valve V ₁ is closed, the valve V ₂ is opened, and clean air or N ₂ is flown into the vacuum storage 1 to completely remove O ₃ . Then, the door 3 may be opened to take out the stored material 2 in a clean state outside the room.

According to an experiment conducted by the inventor, when air is used as the cleaning gas, the air is kept flowing at a flow rate of 10 L (liter) / min for 20 to 30 minutes, and ultraviolet rays are used. By irradiating a 10 W mercury lamp as the lamp 4 for 20 to 30 minutes, the organic film of the stored material 2 could be completely removed, and this could be confirmed by the contact angle method. In contrast to the method of using air and ultraviolet rays, the method of combining O ₂ and ultraviolet rays or the method of combining O ₃ and ultraviolet rays requires a shorter time for removing organic substances and is more effective.

2 to 7 show other embodiments. In these drawings, constituent elements having the same functions and functions as those of FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. To do. FIG. 2 is a flow sheet showing a vacuum storage according to the second embodiment of the present invention, and the vacuum storage shows an elevation. The vacuum storage 1 according to the present embodiment is of a type in which a wafer or a glass substrate as a storage 2 is horizontally oriented and a plurality of upper and lower stages are stored. An ultraviolet lamp 4 is attached to each stage. The number of steps to store is 1 vacuum storage
Can be arbitrarily selected depending on the balance between the size and the place where the stored item 2 is placed. Also, in the vacuum storage 1,
A door 3 for loading / unloading the storage item 2 is attached. The vacuum storage 1 of this type has an advantage that the installation area is smaller than that of the vacuum storage 1 of the first embodiment. In addition, in the second embodiment, other configurations and operation procedures are the same as those in the first embodiment.

FIG. 3 is a flow sheet showing a vacuum storage according to the third embodiment of the present invention, and FIG. 4 is a plan sectional view of the vacuum storage. The vacuum storage 1 according to this embodiment has a circular shape as shown in FIG. 4, and the wafers or glass substrates as the storage items 2 are arranged substantially concentrically inside the storage 1 and the vertical direction is set. Stored for. Further, the plurality of ultraviolet lamps 4 are oriented in the vertical direction and are evenly arranged in the central portion of the vacuum storage 1. A door 3 for loading and unloading the storage item 2 is attached to the vacuum storage 1.
In addition, in the third embodiment, other configurations and operation procedures are the same as those in the first embodiment.

FIG. 5 is a view showing a modification of the third embodiment shown in FIG. 4, and is a plan sectional view of the vacuum storage 1. In the vacuum storage according to this modification, wafers or glass substrates as the storage items 2 are arranged substantially concentrically and in layers, and are stored in the vertical direction. Although FIG. 5 shows the case of two layers, the outer layer and the inner layer, any number of layers may be used depending on the size of the storage and the storage item 2. Further, the plurality of ultraviolet lamps 4 in the vacuum storage 1 are arranged in the longitudinal direction, evenly between the stored items 2 and in the center of the storage 1.

FIG. 6 is a flow sheet showing a vacuum storage according to the fourth embodiment of the present invention, in which the vacuum storage is in an upright position. In this embodiment, the vacuum storage 1 has a storage room 3 inside.
It is divided into 0, a robot room 31, and a load lock room 32. A gate valve V ₄ is provided between the storage chamber 30 and the robot chamber 31, and a gate valve V ₅ is provided between the robot chamber 31 and the load lock chamber 32. Inside the robot chamber 31, a vacuum chamber robot 35 for moving the stored item 2 between the chambers 30 and 31 is installed, and an ultraviolet lamp 4 for irradiating the stored item 2 with ultraviolet rays. Is installed. This type of vacuum storage is a type in which one or a few sheets of the stored material 2 are horizontally placed and are stored in a multi-tiered manner up and down with a certain space between them.
Can be carried in and out of the load lock chamber 32 together with the stocker. Further, storage can be performed for each stocker, and a large number of stockers can be stored according to the size of the storage room 30.

A storage chamber 30, a robot chamber 31, and a load lock chamber 32 are provided via valves V ₆ , V ₇ , V ₈ and a pipe 6.
Each chamber 3 is connected by a vacuum pump 7 that communicates with
Each of 0, 31, and 32 changes from atmospheric pressure to a vacuum state.

[0021] from the supply unit 8 is supplied with air or O ₂ through the filter 9, also O ₃ from an ozone generator 10
Is supplied and passes through the filter 9. The air from which foreign substances have been removed by the filter 9 and the cleaning gas of either O ₂ or O ₃ are introduced into the robot chamber 31 after passing through the pipe 11 and the valve V ₁ . Further, air or N ₂ is supplied from the supply unit 13, and after foreign matter is removed by the filter 14,
After passing through the pipe 15 and valves V ₂ and V ₃ , the robot room 3
1 and the load lock chamber 32, respectively.

The gas inside the robot chamber 31 is a valve V
After passing through ₉ , it is treated by an exhaust gas treatment device 19 equipped with activated carbon for ozone treatment, and an exhaust gas vacuum pump 20
Is discharged to the outside of the system.

Next, an operation procedure of the vacuum storage having the above configuration will be described. The storage room 30 and the robot room 31 are set in a vacuum state in advance. First, the load lock chamber 32 under atmospheric pressure
Open the door 3 and put the wafer or glass substrate storage 2 in the room. At this time, the storage item 2 may be stored together with the stocker. Then, the valve V ₈ is opened and the load pump chamber 32 is evacuated by the vacuum pump 7. When the pressure inside the load lock chamber 32 becomes almost the same as that of the storage chamber 30 and the robot chamber 31, the gate valves V ₄ and V ₅ are opened. And
The storage item 2 is transferred from the load lock chamber 32 to the storage chamber 30 by using the robot 35, and when this is completed, the gate valves V ₄ and V ₅ are closed and the storage item 2 is stored in the storage chamber 30 under a predetermined vacuum degree. Store for a specified time at. Then, when the storage is completed, the valve V ₄ is opened, the stored storage item 2 is taken out by the robot 35 into the robot chamber 31, and the valve V ₄ is closed. The valve V ₇ for a vacuum pump 7 is also closed. Then, open the valve V ₂ and clean N
₂ or air (Cleanliness at this time is 0.1 μm and is class 10
The following) is supplied from the supply unit 13 to the robot chamber 31 to bring the robot chamber 31 to atmospheric pressure. When the robot chamber 31 reaches atmospheric pressure, the valve V ₂ is closed and the ultraviolet lamp 4 is turned on to irradiate the stored item 2 with ultraviolet rays. Then valve V
_{When 9} is opened, the exhaust gas vacuum pump 20 is driven to start discharging the gas in the robot chamber 31. Then, the valve V ₁ is opened to supply the cleaning air or O ₂ from the supply unit 8 or the cleaning O ₃ is supplied from the ozone generator 10, and these cleaning gas (each cleanliness is 0. 1 μm, class 10 or less) is kept flowing at a predetermined flow rate for a predetermined time.
In this way, the cleaning gas is sent into the robot room 31,
By filling the inside of the robot chamber 31 with a cleaning gas and irradiating the stored material 2 with ultraviolet rays, the organic substances adhering to the stored material 2 during vacuum storage are removed and cleaned. When this cleaning is completed, the valve V ₁ is closed and the valve V ₂ is opened to clean air or N ₂ with the robot chamber 3.
Run to 1 to completely remove O ₃ . Then the valve V ₃
To open the load lock chamber 32 to the atmospheric pressure with clean air (class 10 or less at 0.1 μm) or N ₂ and open the valve V ₅ to transfer the stored material 2 to the load lock chamber 32 by the robot 35. After that, the door 3 can be taken out of the room. In addition, when removing the second and subsequent stored items 2,
The robot chamber 31 is evacuated again and the same operation is repeated. As described above, by providing the robot chamber 31 and the load lock chamber 32 in addition to the storage chamber 30, the storage chamber 30 for storing the storage item 2 can be always kept in a vacuum state.

FIG. 7 is a flow sheet showing a vacuum storage according to the fifth embodiment of the present invention, in which the vacuum storage shows an elevation. This embodiment is a modification of the fourth embodiment, and this vacuum storage 1 has one or a few of the stored items 2 in the same horizontal direction as the fourth embodiment, with a certain space between them in a vertical stack. It is a type to store, and the stored items 2 together with the stocker are in the load lock chamber 3
2 can be loaded and unloaded.
Further, each stocker can be stored, and a large number of stockers can be stored according to the size of the storage room 30. In this embodiment, the inside of the vacuum storage 1 is divided into a storage chamber 30, first and second robot chambers 31a and 31b, an ultraviolet irradiation chamber 40, and a load lock chamber 32.

In the present embodiment, the ultraviolet lamp 4 is arranged in the ultraviolet irradiation chamber 40, and the first robot 35a is provided on both sides of the ultraviolet irradiation chamber 40 via gate valves V ₆ and V _7. A first robot room 31a and a second robot room 31b having a second robot 35b are arranged. Between the storage chamber 30 and the first robot chamber 31a is partitioned by a gate valve V _5, it is separated by a gate valve V ₈ and the second robot chamber 31b and the load lock chamber 32.

The valve V _{1 at} the outlet of the filter 9 is connected to the ultraviolet irradiation chamber 40, and the valves V ₂ , V ₃ and V _{4 at} the outlet of the filter 14 are the ultraviolet irradiation chamber 40, the second robot chamber 31b, Each is connected to the load lock chamber 32. Further, the valve V ₉ on the inlet side of the vacuum pump 7 is in the storage chamber 30, and the valves V ₁₀ and V ₁₂ are the first and second valves, respectively.
The valve V ₁₃ is connected to the load lock chamber 32, and the valve V ₁₁ is connected to the ultraviolet irradiation chamber 40 in the robot chambers 31a and 31b. Further, the valve V ₁₄ on the inlet side of the exhaust gas treatment device 19 is connected to the ultraviolet irradiation chamber 40.

Next, the operation procedure of the vacuum storage having the above configuration will be described. The storage room 30 and the first and second robot rooms 31a,
31b and the ultraviolet irradiation chamber 40 are beforehand made into a vacuum state. First, the door 3 of the load lock chamber 32 under atmospheric pressure is opened, and the storage item 2 such as a wafer or a glass substrate is put into the room. At this time, the storage item 2 may be stored together with the stocker.
Then, the valve V ₁₃ is opened and the load pump chamber 32 is evacuated by the vacuum pump 7. The inside of the load lock chamber 32 is the storage chamber 30, and the first and second robot chambers 31a and 31.
b. When the pressure becomes almost the same as that of the ultraviolet irradiation chamber 40, the valves V ₅ , V ₆ , V ₇ and V ₈ for partitioning are opened. Then, the storage object 2 is transferred from the load lock chamber 32 to the storage chamber 30 using the first and second robots 35a and 35b. When this is completed, the valves V ₅ , V ₆ , V ₇ and V ₈ are closed and the storage object 2 is stored in the storage chamber 30 under a predetermined vacuum degree for a predetermined time. Then, when the storage is completed, the valve V
₅ and V ₆ are opened, the stored article 2 that has been stored is taken out to the ultraviolet irradiation chamber 40 by the first robot 35a, and the valves V ₅ and V ₆ are closed. Also, the valve V ₁₁ for the vacuum pump 7
Also close and stop evacuation. Then, open the valve V ₂ and clean N ₂ or air (cleanness at this time is 0.1 μm).
Is supplied to the ultraviolet irradiation chamber 40 from the supply unit 13 to bring the ultraviolet irradiation chamber 40 to atmospheric pressure. When the ultraviolet irradiation chamber 40 becomes atmospheric pressure, close the valve V ₂ .
The ultraviolet lamp 4 is turned on to irradiate the stored item 2 with ultraviolet rays. At this time, the second robot chamber 31b and the load lock chamber 3
Similarly, clean gas is similarly supplied to 2 and kept at atmospheric pressure. Next, the valve V ₁₄ is opened and the exhaust gas vacuum pump 20 is driven to start discharging the gas in the ultraviolet irradiation chamber 40. Then, the valve V ₁ is opened and the cleaning air or O
₂ is supplied from the supply part 8 or O ₃ for cleaning is supplied from the ozone generator 10, and these cleaning gases (each cleanliness is 0.1 μm and class 10 or less) at a predetermined flow rate for a predetermined time. Keep flowing. Thus, the cleaning gas is supplied to the ultraviolet irradiation chamber 4
By feeding it into the chamber 0 and filling the inside of the irradiation chamber 1 with a cleaning gas and irradiating the stored material 2 with ultraviolet rays, the organic substances adhering to the stored material 2 during vacuum storage are removed and cleaned. When this cleaning is completed, the valve V ₁ is closed, the valve V ₂ is opened, and clean air or N ₂ is flown into the ultraviolet irradiation chamber 40 to completely remove O ₃ . Then
The valve V ₂ may be closed and the valves V ₇ and V ₈ may be opened, the second robot 35 b may transfer the stored material 2 from the ultraviolet irradiation chamber 40 to the load lock chamber 32, and then may be taken out from the door 3 to the outside. When the second and subsequent stored items 2 are taken out, the ultraviolet irradiation chamber 40 is evacuated again and the same operation is repeated. As described above, by providing the first and second robot chambers 31a and 31b, the ultraviolet irradiation chamber 40, and the load lock chamber 32 in addition to the storage chamber 30, the storage chamber 30 for storing the storage object 2 is always kept in a vacuum. You can Moreover, since O ₃ , water (H ₂ O), and carbon dioxide (CO ₂ ) generated during cleaning are kept only in the ultraviolet irradiation chamber 40, it is possible to prevent contamination of other chambers.

[0028]

As described above, according to the present invention, it is possible to effectively remove the pollutants consisting of carbon-based organic substances attached to the stored materials that are vacuum-stored.

[Brief description of drawings]

FIG. 1 is a flow sheet showing a vacuum storage according to a first embodiment of the present invention.

FIG. 2 is a flow sheet showing a vacuum storage according to a second embodiment of the present invention.

FIG. 3 is a flow sheet showing a vacuum storage according to a third embodiment of the present invention.

FIG. 4 is a plan sectional view of the vacuum storage shown in FIG.

5 is a view showing a modification of the third embodiment shown in FIG. 4, and is a plan sectional view of a vacuum storage.

FIG. 6 is a flow sheet showing a vacuum storage according to a fourth embodiment of the present invention.

FIG. 7 is a flow sheet showing a vacuum storage according to a fifth embodiment of the present invention.

[Explanation of symbols]

1 Vacuum Storage 2 Storage 3 Door 4 UV Lamp 7 Vacuum Pump 8 Supplying Unit 9, 14 Filter 10 Ozone Generator 19 Exhaust Gas Treatment Device 20 Exhaust Gas Vacuum Pump 30 Storage Room 31 Robot Room 32 Load Lock Room V ₁ ~ V ₁₄ Valve 40 Ultraviolet irradiation chamber 50 Supply device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Yoshioka 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company EBARA Research Institute

Claims (2)

[Claims] 1. A vacuum storage, comprising: a vacuum storage chamber for storing the storage product; and an ultraviolet lamp provided in the vacuum storage chamber or a chamber in the vicinity thereof to irradiate the storage product with ultraviolet rays. 2. The vacuum storage according to claim 1, further comprising a supply device for supplying a cleaning gas of at least one of air, oxygen and ozone to the chamber provided with the ultraviolet lamp. Warehouse.