JP3494293B2 - Method and apparatus for cleaning closed container - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cleaning a hermetically sealed container for housing a semiconductor substrate such as a wafer.

[0002]

2. Description of the Related Art Semiconductor manufacturing requires a large number of steps to be carried out under a very high degree of cleanliness, but it is costly to keep a vast environment covering all steps to a high degree of cleanliness. For this reason, recently, development of means for keeping only the local environment (mini environment) at a high degree of cleanliness has been advanced. For example, FOUP wafer
(Front Opening Unified Pod) The wafer is transferred in a sealed container, the wafer is put into the semiconductor manufacturing process together with the sealed container, and the sealed container is directly docked with the manufacturing equipment to proceed with the work. It is possible to maintain high cleanliness of the wafer in the manufacturing process by controlling the above.

By the way, in such a hermetically-sealed container, a large number of wafers are stored and transported. At that time, the wafers and the inner surface of the container are rubbed with each other to cause contamination such as particles, and the container is clean. Since it is transferred to a low-temperature place, the outer surface is easily contaminated, and there is a risk of contaminating the wafer stored inside when the lid is removed. Therefore, it is necessary to wash the container regularly.

Conventionally, in the method of cleaning a closed container, the container body is placed in a cleaning tank with the opening facing downward with the lid removed, and first the inner and outer surfaces are cleaned by a high pressure shower and then cleaned. When the process is completed, clean hot air is blown inside and outside the container to dry it.

[0005]

However, a closed container for storing a semiconductor substrate such as a wafer needs to remove dirt of submicron particles, but a satisfactory cleaning property can be obtained only by cleaning with a high pressure shower. Absent. Further, also in the drying after cleaning, it takes about 40 minutes to completely dry by a warm air blow in a container having a complicated shape and many overlapping portions such as a wafer transfer container. It may be possible to shorten the drying time by raising the temperature of the warm air, but the temperature cannot be raised too high because the material of the container is resin (heat resistance 100 ° C) (usually 7
0-80 ° C).

An object of the present invention is to provide a cleaning method and a cleaning device for a hermetically sealed container capable of cleaning and removing even attached submicron particles and drying in a short time.

[0007]

In order to solve the above problems, the present invention employs the following means. The method for cleaning a hermetically sealed container according to claim 1, wherein a cleaning liquid is supplied into the ultrasonic cleaning tank, and when the hermetically sealed container with the lid removed is immersed in the cleaning liquid with its opening facing downward, the inside of the container is washed. To
Residual air is generated in the bottom of the container due to the pressure of the cleaning liquid.
Air bleed pie placed so that its tip can reach in the vicinity
Is automatically discharged from the container, and ultrasonic cleaning is performed in this state, and a cleaning process including discharging the cleaning liquid or cleaning the inside and outside of the container with a high pressure shower, and the cleaning process are completed. It is provided with a drying step including a step of transporting the sealed container to a drying tank and sending hot air to heat it with hot air, and a step of decompressing and drying the inside of the drying tank under reduced pressure. In this case, the cleaning step is configured to alternately repeat the ultrasonic cleaning step and the high pressure shower cleaning step a plurality of times, and the drying step also includes hot air heating and a depressurizing step alternately a plurality of times. It is preferably configured to repeat.

According to a third aspect of the present invention, there is provided a device for cleaning a hermetically-sealed container, which has a mechanism for mounting and hoisting a hermetically-sealed container with a lid removed, with an opening thereof facing down, and a high-pressure shower for injecting a cleaning liquid. Air that remains inside the container when the container is immersed in the cleaning liquid is a liquid of the cleaning liquid.
Since it is automatically discharged by pressure, it is placed near the bottom inside the container.
Equipped with an air bleeding pipe arranged so that the tip of the
In addition to having an ultrasonic cleaning tank that can perform ultrasonic cleaning by ultrasonic vibration , and a hot air blowing mechanism that stores hot air and heats the hot air by storing the sealed container that has completed the cleaning process by the ultrasonic cleaning tank, And a drying tank having a pressure reducing mechanism for reducing the pressure. In this case, the ultrasonic cleaning tank is configured to alternately repeat high pressure shower cleaning and ultrasonic cleaning a plurality of times, and the drying tank is also configured to alternately repeat hot air heating and reduced pressure drying a plurality of times. Is preferred.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a closed container cleaning apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing an embodiment of a closed container cleaning device according to the present invention. Unlike the conventional cleaning device 10 for a closed container, the cleaning part and the drying part are separated. That is, the cleaning unit is composed of the cleaning tank 20, and the drying unit is composed of the drying tank 30. The cleaning tank 20 has a cleaning tank main body 21 capable of storing a cleaning liquid, and an ultrasonic transducer 22 is attached to the bottom surface of the cleaning tank main body 21 so that ultrasonic cleaning can be performed. Has been done. The cleaning tank 20 also has a pedestal 23 on which the closed container 100 with the lid removed is placed with the opening facing down. The pedestal 23 is the cleaning tank main body 21.
It is configured to be movable up and down so as to receive the hermetically-sealed container 100 above the liquid surface of and to put it in and out of the cleaning liquid 24 stored in the cleaning tank main body 21. The closed container 1
It is naturally possible to lower the pedestal 23 on which 00 is placed in the cleaning tank main body 21 and supply the cleaning liquid 24 later.

When the hermetically sealed container 100 with the opening facing downward is dipped in the cleaning liquid, a mechanism for discharging the air accumulated inside the hermetically sealed container 100 is required. As shown in FIG. 3, the cleaning tank 20 is provided with an air bleed pipe 25 that is integrally assembled with the pedestal 23 and has a tip portion reaching the vicinity of the bottom of the sealed container 100 placed on the pedestal 23. As the pedestal 23 descends and the hermetically sealed container 100 is immersed in the cleaning liquid, the pressure of the air remaining in the container 100 increases due to the weight of the container 100 and the air is naturally discharged through the air vent pipe 25. To be done. The air bleeding pipe 25 may be fixed in the cleaning tank main body 21 by a support 26 as shown in FIG. In that case, when the pedestal 23 descends and the hermetically-sealed container 100 is immersed in the cleaning liquid and comes to the lowermost end of the air bleeding pipe 25,
It is necessary to arrange so as to reach the vicinity of the bottom of the hermetically sealed container 100. When this method is used, the cleaning liquid is a closed container 10.
0 is supplied in a state of being placed on the pedestal 23 in the cleaning tank main body 21. As the cleaning liquid is supplied and the liquid level in the cleaning tank main body 21 rises, the air in the sealed container 100 is gradually discharged through the air vent pipe 25.

Further, a high-pressure shower pipe 27 for injecting a cleaning liquid from the tip portion for cleaning the inner surface of the hermetically sealed container 100 is juxtaposed on the pedestal 23 of the cleaning tank 20 and the cleaning tank main body 21 A large number of nozzles 28 are also provided on the side surface for high-pressure shower cleaning of the outer surface of the closed container 100, and high-pressure shower pipes (not shown) are connected to these nozzles 28. When the air bleeding pipe 25 is directly attached to the cleaning tank body 21 side as described above, the high-pressure shower pipe 27 is also provided on the cleaning tank body 21 side. Further, in the figure, reference numeral 29 is an overflow device provided on the side surface of the cleaning tank main body 21. Further, the mechanism for supplying the cleaning liquid and the mechanism for discharging the cleaning liquid have the same configurations as the conventional ones, so that the illustration thereof is omitted.

Next, the drying tank 30 will be described. As shown in FIG. 1, the drying tank 30 has a slide lid 31a on the upper side.
Has a closed type drying tank main body 31, and inside the drying tank main body 31, there is provided a pedestal 33 on which the closed type container 100 with the opening facing downward is placed. A hot air blower 34 is attached to the drying tank body 31. The hot air blower 34 includes a blower 34a, a heater 34
b, Filter (HEPA: high efficiency particulate fi
lter) 34c, and is connected to the drying tank main body 31 by a pipe 36 via a valve V1. Further, a part 36 a of the pipe 36 is branched and penetrates a side surface of the drying tank main body 31 and extends upward from the lower side of the pedestal 33, and the sealed container 100 placed on the pedestal 33 is provided. Hot air (70 to 80 ° C., maximum 90 ° C.) can be sent to the inner surface like the outer surface.

Further, an exhaust pipe 37 is attached to the bottom surface of the drying tank main body 31, and a vacuum pump 35 is attached to the exhaust pipe 37 via a valve V2, and the exhaust pipe is also attached. 37 is configured so that hot air can be exhausted via the valve V3 and drain can also be exhausted via the valve V4.

Next, a method of using the cleaning device for the sealed container 100 will be described. First, the sealed container 100, which is an object to be cleaned, is conveyed by the carrier 50 as shown in FIG.
Is conveyed to the cleaning tank 20 shown in FIG. Carrier machine 50
Has a main body 51 that is movable in the left-right direction and can be moved up and down. Two parallel bars 52 extend horizontally from an upper portion 51a of the main body 51, and each bar 52 has two arms. 53 is fixed vertically. The lower end of each arm 53 is bent inward, and the hook 53a that supports the end of the opening of the closed container 100 with the opening on the lower side.
Is formed as. In addition, the bar 52 is the main body 5
1 is configured to rotate by a device provided in the upper portion 51a of the first bar 51. When the bar 52 is rotated, the bar 5 is rotated.
The arm 53 fixed to 2 moves like the arrow A in the figure.

By the hook 53a of this arm 53,
The opening 100 supports the end of the opening of the hermetically-sealed container 100 with the opening facing downward and conveys the container 100 to above the cleaning tank 20.
The arm 53 is opened and the container 100 is transferred to the pedestal 23. A predetermined amount of pure water (cleaning liquid) is supplied into the cleaning tank body 21.
When the supply of pure water is complete, close valve V5 and
Keep open. The pedestal 23 on which the container 100 is placed is integrated with the air bleeding pipe 25 to clean the cleaning liquid 2 of the cleaning tank main body 21.
It descends into 4. The air accumulated inside the container 100 is naturally discharged through the valve V6 opened through the air bleeding pipe 25. When the pedestal 23 descends to a predetermined position, it stops, and the ultrasonic transducer 22 attached to the bottom surface of the cleaning tank body 21 is vibrated to ultrasonically clean the container 100.

After ultrasonic cleaning for a predetermined time, the cleaning liquid 24 in the cleaning tank main body 21 is drained, the valve V6 is closed and the valve V5 is opened to deionize pure water into the high pressure shower pipe 27.
And the nozzle 28 to perform high pressure shower cleaning on the inner and outer surfaces of the container 100. At this time, naturally, the drain port of the cleaning tank main body 21 is left open, and the pure water used in the high-pressure shower is discharged. After high-pressure shower cleaning for a predetermined time, the drain port of the cleaning tank main body 21 is closed and pure water is supplied into the cleaning tank main body 21, ultrasonic cleaning is performed for a predetermined time in the same manner as above, drainage is performed, and then high-pressure shower cleaning is performed. To do. Ultrasonic cleaning and high-pressure shower cleaning are alternately repeated several times to complete the cleaning. Of course, if the stain can be removed without repeating, it is not necessary to repeat. In the above example, the cleaning liquid 24 is discharged when performing the high-pressure shower cleaning, but the submerged jet cleaning may be performed without discharging the cleaning liquid 24. Further, only one of ultrasonic cleaning and high-pressure shower cleaning can be performed depending on the type of dirt to be cleaned.

When the cleaning is completed, the pedestal 23 rises above the cleaning tank main body 21, and the container 100 is received by the arm 53 of the carrier 50 and conveyed to above the drying tank 30. When the lid 31a on the upper portion of the drying tank main body 31 is opened, the carrier 50 descends and transfers the container 100 to the pedestal 33 provided in the drying tank main body 31. Conveyor 50 with container 100 released
Rises and the lid 31a of the drying tank body 31 is closed.

First, with the valves V1, V3 and V4 opened, hot air is blown from the hot air blower 34 into the drying tank main body 31 to heat the container 100. After a predetermined time has elapsed, the valves V1, V3 and V4 are closed, the valve V2 is opened, the vacuum pump 35 is operated, the interior of the dryer main body 31 is decompressed, and the container 100 is dried under reduced pressure. After decompressing for a predetermined time, the valve V7 is opened to open the inside of the drying tank main body 31 to the atmosphere, and after returning to normal pressure, the valves V1, V3 and V4 are opened and the inside of the drying tank main body 31 is again fed from the hot air blower 34. Hot air is sent to heat the container 100, and after a predetermined time has elapsed, vacuum drying is performed again. Hot air heating and reduced pressure drying are repeated several times to complete the drying. In this case as well, like the washing, it is not necessary to repeat the steps as long as sufficient drying can be performed without repeating the steps. When the drying is completed, the lid 31a on the upper part of the drying tank main body 31 is opened, the container 100 is taken out of the drying tank main body 31 by the carrier 50, and the cleaning of the container 100 is completed.

The container 100 is dried by a closed type drying tank main body 3
Since hot air heating and reduced pressure drying are alternately repeated in 1,
It took 10 minutes to dry in the conventional drying method.
I was able to shorten to about a minute.

[0020]

As described above, according to the present invention,
Since the cleaning tank and the drying tank are separated so that ultrasonic cleaning and high-pressure shower cleaning can be alternately performed in the cleaning tank, even sub-micron dust can be cleaned, and hot air heating and vacuum drying alternate in the drying tank. Therefore, the drying time can be greatly shortened.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a carrier used in the present invention.

FIG. 3 is a diagram showing an example of a positional relationship between a pedestal of an ultrasonic cleaning tank and a high-pressure shower that constitute the present invention.

FIG. 4 is a diagram showing another example of the installation position of the high-pressure shower in the ultrasonic cleaning tank that constitutes the present invention.

[Explanation of symbols]

10 Airtight container cleaning device 20 washing tank 21 Cleaning tank body 22 Ultrasonic transducer 23 cradle 24 cleaning liquid 25 Air bleeding pipe 27 High-pressure shower piping 28 nozzles 30 drying tank 33 pedestal 34 Hot air blower 35 vacuum pump 50 carrier 100 airtight container

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B08B 9/28 B08B 3/02 B08B 3/12 H01L 21/304 648 H01L 21/68

Claims (4)

(57) [Claims] 1. When an airtight container having a lid and a cleaning liquid is supplied into the ultrasonic cleaning tank and the lid is removed, the closed container is immersed in the cleaning liquid and remains inside the container.
Due to the hydraulic pressure of the cleaning liquid, the
Automatic from the air bleeding pipe arranged so that the tip can reach
Of the cleaning solution, and a cleaning step including a step of performing ultrasonic cleaning in this state, a step of discharging the cleaning liquid or cleaning the inside and outside of the container with a high-pressure shower, and a closed mold after the cleaning step. A method for cleaning a hermetically-sealed container, comprising: a step of transporting the container to a drying tank and sending hot air to heat the same with hot air; and a drying step including a step of decompressing and drying the inside of the drying tank under reduced pressure. 2. The cleaning step is configured to alternately repeat the ultrasonic cleaning step and the high pressure shower cleaning step a plurality of times, and the drying step also alternates between hot air heating step and depressurizing step. The method for cleaning a hermetically sealed container according to claim 1, wherein the method is repeated a plurality of times. 3. A hermetically-sealed container with a lid removed is provided with a mechanism for mounting and elevating the container with the opening thereof facing down,
A container having a high-pressure shower for injecting a cleaning liquid, and when the container is immersed in the cleaning liquid, air remaining inside the container is automatically discharged by the liquid pressure of the cleaning liquid.
Air placed so that its tip reaches near the inside bottom.
An ultrasonic cleaning tank equipped with a drain pipe and capable of ultrasonic cleaning by ultrasonic vibration , and a hot air blowing mechanism for sending hot air and heating hot air by housing a sealed container that has completed the cleaning process by the ultrasonic cleaning tank A cleaning device for a hermetically-sealed container having a drying tank having a depressurizing mechanism for depressurizing the inside. 4. The ultrasonic cleaning tank is configured to alternately repeat high-pressure shower cleaning and ultrasonic cleaning a plurality of times, and the drying tank also alternately repeats hot air heating and reduced pressure drying a plurality of times. The cleaning device for a hermetically sealed container according to claim 3, wherein the cleaning device is configured as follows.