JP3252456B2 - Method and apparatus for purging gas in 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 gas purging method for a portable closed container or the like used in a clean room, and a method for purging the same.
Device .

[0002]

2. Description of the Related Art For example, semiconductors are manufactured in a clean room where the internal atmosphere is cleaned, and the semiconductor wafers and liquid crystal substrates are transported and stored in the clean room in order to prevent dust from adhering to the semiconductor wafers. And the like are stored in a portable closed container.

Further, in recent years, in order to prevent the growth of an oxide film due to natural oxidation of a semiconductor wafer, the atmosphere inside the closed container is replaced with a gas inert to the wafer, such as nitrogen N2 gas or dry air. I have.

FIG. 6 shows an example of a closed container provided with the N2 gas purging function. In the figure, 10 is a main body of a portable closed container (POD) 1, 11 is a flange provided in an opening 12 of the main body 10, 13 and 13 A are sealing materials, 14 is a handle, 20 is a lid of the closed container, Reference numeral 30 denotes a wafer cassette that stores semiconductor wafers W. Reference numeral 40 denotes a sealed case of a semiconductor surface treatment apparatus, which accommodates a not-shown surface treatment reaction furnace, a transport mechanism including an elevating device, and the like. Reference numeral 42 denotes an opening for taking in and out the wafer cassette, which is provided in a part of the upper wall 41 of the case 40. The upper wall 41 is provided with a gas supply pipe 44A, one end of which is open on the peripheral surface of the opening 42 and the other end of which is connected to an inert gas cylinder (N2 gas cylinder in this example) 50. An exhaust gas pipe 44B which is open on the peripheral surface and the other end of which is open outside the box is provided. 45A
Is an air supply valve, and 45B is an exhaust valve. Reference numeral 46 denotes a lifting platform of the lifting device 100, which is provided in the opening 42.
Has a size that allows it to be inserted with a gap G left between it and the peripheral surface. 40A is a lock mechanism for pressing the flange 11 of the closed container 1. The inside of the sealed case 40 is in a nitrogen N2 gas atmosphere, and is pre-pressed slightly above atmospheric pressure.

The lid 20 of the closed container is a hollow body and has a lock mechanism as shown in FIG. 7, for example. 24
Is a cam, 25 is a plate-shaped lock arm, which has a rolling element 25a and is cantilevered so as to be able to advance and retreat in the longitudinal direction and to be tiltable. 26 is a fulcrum member, and 27 is a spring.
The camshaft 28 extends into the lid 20 from the center of the upper wall of the elevator 46, and is spline-engaged with the cam 44 when the lid 20 is concentrically mounted on the elevator 46. The elevating table 46 has a built-in camshaft drive mechanism 29 for rotating the camshaft 28 by a predetermined angle, and the camshaft drive mechanism 29 and the camshaft 28 constitute an unlocking / locking mechanism. Note that a recess 12 </ b> A with which the lock arm 25 is engaged is formed on the inner peripheral surface of the opening 12 of the main body 10.

[0006]

As described above, in recent years, the wafer cassette has been transported and stored in a sealed container filled with nitrogen N2 gas. However, the inside of the sealed container is filled with nitrogen N2 gas or the like. H2O and O2 (hereinafter, adsorbed / occluded gas and liquid) adhering to the inner surface of the closed container, the wafer cassette, and the surface of the cassette contained in the wafer cassette can be sufficiently removed by merely replacing with an inert gas. As a result, these components come out into the closed container with the passage of time, the concentration of H2 O and O2 in the closed container increases, an oxide film is formed on the wafer by natural oxidation, and the yield decreases. .

In order to prevent this, the present inventors have proposed a method in which the inside of a portable closed container is evacuated and then purged with an inert gas.

That is, as shown in FIG.
The closed container 1 is placed on the upper wall 60U of the closed box 60 connected to the vacuum source 90 and the inert gas source 50 through 69, and the bottom cover 20 is unlocked. (The bottom lid 20 is also lowered to the position shown by the dashed line), the inside of the closed container 1 is communicated with the inside of the closed box 60, and after vacuum evacuation, gas purge is performed with an inert gas. Reference numerals 91 and 92 denote on-off valves. In FIG.
The illustration of the lock mechanism 40A is omitted.

In this method, since the inside of the container 1 is once evacuated, moisture and oxygen adhering to the inner surface of the container 1 and the bottom cover 20, wafers and wafers (not shown) in the container 1 are not shown. Moisture and oxygen adhering to the surface of the cassette evaporate from the inner surface and the surface, separate from the inner surface and the surface, and are exhausted to the outside, and then the container 1 is replaced with N2 gas. become.

FIG. 5 (a) shows the change in H2O concentration in the closed vessel after gas purging after evacuation, and FIG. 5 (b) shows the change in H2O concentration in the closed vessel after the conventional gas purging. Shows the change in concentration. Also, FIG.
Shows the change of the O2 concentration in the closed vessel after gas purging after the evacuation, and (d) of the same figure shows the change of the O2 concentration after the O2 concentration was reduced to 0 ppm by the conventional method. . The capacity of the sealed container used in this experiment was 540 liters, and the sealed container was tested with four wafer cassettes each containing 25 wafers.

As is apparent from the experimental results, when the inert gas purge is performed after the evacuation, the H 2 O coming out of the inner surface of the container, the wafer, and the wafer cassette is removed.
Since the amount of O2 and O2 is significantly reduced as compared with the conventional case, it is possible to suppress the growth of the natural oxide film even when stored in a container for a long time.

In the case of FIG. 4 where the inside of the container is evacuated,
Due to the pressure difference between the inside and outside of the container 1,
The body 10 of the container 1 had to withstand the pressure difference. Therefore, it is necessary to increase the negative pressure resistance by increasing the thickness of the container, or to use a special structure that can withstand the negative pressure. However, these raise the cost and increase the weight and are difficult to carry.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and in the case of purging with an inert gas after evacuation, a method and an apparatus for purging gas in a closed container which do not need to consider the pressure difference. The purpose is to provide.

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a method for manufacturing an airtight container, comprising the steps of:
By raising and lowering the removable bottom cover,
Container storage items such as boards for electronic devices are passed through the opening.
When storing in a closed container,
After evacuating through the above opening, it becomes container storage
In the method of purging with inert gas,
Close box to vacuum source and inert gas source through each pipe
The main body to be contacted and the container to store the closed container
Compartment, and the main unit and
Provide a communication hole with equal pressure in the
An opening is provided for the bottom lid and container storage.
The closed container on the wall so as to cover the opening.
Place the container tightly and place the bottom lid of the container through the opening.
And lowering it into the main unit,
Open the inside of the box inside
Gas purging with inert gas for container storage
It is characterized by performing. The invention of claim 2 is the claim
2. A gas purging method for a closed container according to claim 1, wherein
Section is a box, and the container storage section is covered on this box.
Is divided on the box by a hemispherical cover
It is characterized by: The invention of claim 3 is equivalent to claim 1
Or the gas purging method of a closed container according to 2 above,
The communication hole is provided with a filter.
You. The invention of claim 4 provides any one of claims 1 to 3.
3. The gas purging method for a closed container according to item 1. And the ream
The through-hole is provided with a hole opening / closing mechanism.
It is characterized in that a communication hole is opened at the time of emptying. Contract
The invention according to claim 5 is provided so as to be detachably attached to the opening of the closed container.
By raising and lowering the bottom cover,
Containers, such as boards, are sealed through the above-mentioned opening.
When storing in a container,
Inert to container contents after vacuuming through
Gas purging system for closed containers for purging with natural gas
, A container storage section for storing the closed container
And raise and lower the bottom lid of the closed container in the container storage section.
Lifting and lowering device, as well as a vacuum source and inert gas
Main unit, the container storage unit and main unit
And a closed box having a partition wall for partitioning
The partition wall holds the main unit and container storage
Communication hole with equal pressure to the bottom part, the bottom lid and the container
It is noted that an opening for taking in and out of stored items is formed.
It is a sign. The invention according to claim 6 is the hermetic seal according to claim 1.
This is a container gas purge device, and the main body is a box.
The container storage section is a hemispherical shape covered on this box
Characterized by being partitioned on the box by a cover body of
are doing. The invention according to claim 7 is the invention according to claim 5 or 6.
This is a gas purging device for a closed container, and the communication hole
A filter is provided. Claim
The invention according to claim 8 is a memory according to any one of claims 5 to 7.
A gas sparge at a closed container, the communication hole has a hole opening
A closing mechanism is provided, and this opening and closing mechanism is used for evacuation.
Opening the communication hole.

[0015]

According to the present invention, since the pressure in the main body of the closed box and the pressure in the purge chamber and the container are all the same, the pressure difference between the inside and outside does not act on the container.

[0016]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a closed box 80 is composed of a partition wall 80A, a main body portion A and a purge chamber B which is a container storage portion.
It is divided into and. Reference numeral 83 denotes a lid of the closed box 80, which is attached so as to be opened and closed by a hinge mechanism (not shown). The main body portion A and the storage portion B communicate with each other through a through hole (communication hole) 81 formed in the partition wall 80A.
Is covered with a filter 82. Partition wall 8
0A is used as a pedestal on which the container 1 is placed, and an opening 82 is formed in the partition wall 80A. The elevating table 46 has a size that can be fitted into the opening 85 while leaving a gap G between itself and the peripheral surface of the opening 85. Other configurations are the same as those in FIG.

In this embodiment, the inside of the main body A of the closed box 80 and the inside of the purge chamber B, which is a container accommodating section, are formed with through holes 81.
, The pressure in the main body A, the purge chamber B and the inside of the container 1 are all the same. Therefore, the above-mentioned pressure difference between the inside and outside does not act on the container 1, and it is not necessary to make the container 1 thick or have a special structure.

If the filter 82 is not provided, and dust or the like adheres to the outer peripheral surface of the container 1, the dust enters the main body A through the through hole 81 and enters the main body 10 of the container 1. There is a possibility that the wafer W may enter and contaminate the wafer W, but in this embodiment, the through hole 81 is closed by the filter 82, so there is no possibility of this.

In this embodiment, the vacuum exhaust pipe 6
8 and one end of the gas supply pipe 69 are open to the main body A of the closed box 80, but may be open to the purge chamber B. For example, one end of the vacuum exhaust pipe 68 is The gas supply pipe 69 may be opened to the purge chamber B, and one end of the gas supply pipe 69 may be opened to the main body A.

FIG. 2 shows another embodiment of the present invention. The purging chamber B, which is a container accommodating portion, is partitioned by a hemispherical cover body 84 and is formed in a hemispherical shape, so that the wall thickness is reduced and the strength is reduced. The purge chamber B can be easily formed. That is, the main body portion is formed of a box, and the container storage portion is partitioned on the box by a hemispherical cover body overlaid on the box.

The main body portion A of the closed box 80 and the purge chamber B serving as a container storage portion are connected to each other when vacuuming is performed.
As shown in FIG. 3, a hole opening / closing mechanism such as a pipe 81B having an electromagnetic valve 81A can be used to communicate with each other.
1 and the solenoid valve 81 only during the evacuation.
A may be opened so that the main body A and the purge chamber B communicate with each other. After the evacuation, the pressure in the purge chamber B, which is the container storage section, is returned to normal pressure in order to open the lid.

[0023]

As described above, the present invention has an advantage that a conventional container can be used as the container because the evacuation and the gas replacement are performed without the pressure difference between the inside and outside of the container. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention.

FIG. 3 is a partial view for explaining another example of the through hole in the embodiment.

FIG. 4 is a schematic longitudinal sectional view for explaining a method of purging the gas after evacuation.

[5] and time course of H ₂ O and O ₂ concentration in the container after purging with the method of FIG. 3 and FIG. 4, the time course of H ₂ O and O ₂ concentration in the container after conventional gas purge FIG. 3 is a diagram showing the comparison of FIG.

FIG. 6 is a view showing a conventional portable closed container.

FIG. 7 is a view showing an unlocking / locking mechanism of the portable closed container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 10 Closed container main body 20 Closed container bottom cover 30 Wafer cassette 46 Elevating stand 50 Inert gas cylinder 80 Closed box 80A Partition wall 81 Through hole 82 Filter 83 Cover 84 Cover body 85 Opening 90 Vacuum source 91, 92 Open / close valve 100 Lifting device W Wafer

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hinaya Morita 100 Takegahana-cho, Ise City, Mie Prefecture Inside Kobe Electric Machinery Co., Ltd. (72) Inventor, etc.100 100 Takegahana-cho, Ise City, Mie Prefecture Shinko Electric Machinery Stock (72) Inventor Mitsuhiro Hayashi 100 Takegahana-cho, Ise-shi, Mie Prefecture Shinko Electric Machinery Co., Ltd. (72) Inventor Atsushi Okuno 100-ketakehana-cho, Ise-shi, Mie Prefecture Shinko Electric Machinery Co., Ltd. (72) Inventor Akio Nakamura 100 Takegahana-cho, Ise-shi, Mie Prefecture Inside Ise Works, Shinko Electric Co., Ltd. (56) References JP-A-60-227437 (JP, A) JP-A-4-159918 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/68 B65B 31/04 B65G 49/00

Claims (8)

(57) [Claims] 1. An air conditioner, which is detachably provided in an opening of an airtight container.
By lifting the bottom cover,
Of the container in the closed container through the opening
At the time of storage in the closed container through the opening.
In the method of purging with a gas inert to the container contents after evacuating the container, a closed box is connected to a vacuum source and an inert gas source through each pipe, and a container storage unit for storing the closed container. And the main body on the wall that separates them
Rutotomoni provided communicating hole to equal pressure container accommodating portion,
An opening for taking in and out the bottom lid and container storage
Only, and the sealed container so on the wall so as to cover the opening is placed in an airtight, through the opening the bottom lid of the container
And by lowering the main body portion and opens the inside of the sealed container to the main body portion of the sealed box, gas purge method of sealing a container which is characterized in that the gas purging with an inert gas for evacuation after the container stored items. 2. The container according to claim 1, wherein the main body is a box, and the container storage section is partitioned on the box by a hemispherical cover that covers the box. Gas purge method for closed containers. 3. The gas purging method for a closed container according to claim 1, wherein a filter is provided in the communication hole. 4. The closed container according to claim 1 , wherein the communication hole is provided with a hole opening / closing mechanism, and the hole opening / closing mechanism opens the communication hole upon evacuation. Gas purge method. 5. A detachably provided at an opening of a closed container.
By lifting the bottom cover,
Of the container in the closed container through the opening
At the time of storage in the closed container through the opening.
Gas that is inert to container contents after vacuuming
Contact the gas purge system of the sealed container to purge vinegar
There are a container housing part for housing the sealed container, the Con
Elevating equipment that raises and lowers the bottom lid of the sealed container in the tena storage section
Equipment and communicate with vacuum and inert gas sources
Divided the main body, the container storage section and the main body
And a closed box having a partition wall that separates the main body part and the container storage part from each other.
The communication hole for pressure and the bottom lid and container storage
It is characterized by having an opening for taking in and out
Gas purge device for closed containers. 6. The main body part is a box, and the container storage part is
The box body is a hemispherical cover body covered on this box body.
2. The dense body according to claim 1, wherein the upper part is partitioned.
Gas purge system for closed containers . 7. A filter is provided in the communication hole.
The sealed container according to claim 5 or 6, wherein
Gas purge device . 8. The communication hole is provided with a hole opening / closing mechanism.
The hole opening / closing mechanism is characterized by opening the communication hole when vacuuming.
The sealed core according to any one of claims 5 to 7, wherein
Container gas purge device .