JP2660202B2 - Gas replacement method and processing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a gas replacement method for gas replacement in a container.

(Prior art) In particular, in a device where a reaction process is to be performed, the inside of a sealed container is replaced with an inert gas or the like from the atmosphere (air). Gas replacement is performed by applying a high vacuum and then introducing an inert gas.

However, if the container to be gas-replaced does not have a proof strength against the internal and external pressures and has a relatively flexible structure, the above-described high vacuum cannot be set. Therefore, the gas replacement is performed by introducing the gas to be replaced from one of the containers into the constant flow rate container and exhausting the gas from the other portion.

An example of a container requiring this kind of gas replacement is an N2 glove box used in a liquid phase epitaxial growth apparatus. This N2 glove box is used to carry out various operations for loading and unloading boats to and from the reactor in a N2 gas atmosphere via gloves. From the viewpoint of ensuring the workability, a transparent material such as acrylic is used. Constitutes the container.

In the N2 glove box, for example, when performing crystal growth of a compound semiconductor for manufacturing an LED, a semiconductor laser, etc., particularly when aluminum is used as one component of the mixed crystal, oxygen may be mixed during the process. Oxidation concentration is at least several tens of ppm because luminous efficiency is reduced by oxidation, threshold current at the time of light emission is increased, and reliability and yield as devices are adversely affected.
Need to be reduced to

For this reason, an oxygen concentration monitor is placed in the exhaust system of the gas replacement device, and during the initial operation of the device, after maintenance, etc., gas replacement is performed by the monitor until the oxygen concentration reaches the permissible oxygen concentration. N2 is continuously purged because air that permeates through the container wall surface or the butyl rubber glove is mixed.

(Problems to be Solved by the Invention) According to the conventional gas replacement method described above, it takes a considerable number of days to reach an oxygen concentration of several tens of ppm, and time is required for gas replacement after regular maintenance. The operation rate of the device was extremely low.

According to experiments performed by the inventor, N2 was supplied at a rate of 30 / min in order to bring the oxygen concentration in the N2 glove box to 40 ppm.
Even if it is supplied, it takes one to one and a half days, and usually, the N2 gas is supplied at 10 / min, so that it took about one week.

Therefore, it is an object of the present invention to solve the above-described conventional problems and improve the gas replacement speed while keeping the gas supply amount equal to or less than the conventional one, thereby reducing the time required for the gas replacement work. It is an object of the present invention to provide a gul replacement method that can be significantly reduced.

[Effects of the Invention] (Means for Solving the Problems) According to the present invention, in a container to be replaced with gas, a fluid storage means capable of securing a space by introducing a fluid is disposed, and replacement is performed with the space secured. It is like that.

As such a fluid accommodating means, a film which is always in close contact with a wall surface is formed at a corner of a container which is a dead space where the flow of the replacement gas is poor, and this film and the wall surface are used for gas replacement or the like. It is preferable to introduce a fluid into the fluid.

If there are no obstacles inside the container, for example, in the case of a container having a rectangular cross section, a film that can be surface-contacted on its diagonal line is always held in close contact with the wall surface, and gas replacement is performed. In particular, it is also possible to adopt a configuration in which the gas is introduced so as to abut on a diagonal line.

Further, the container to be replaced with gas is arranged between the atmosphere and the processing chamber, and when the object to be processed is carried into the processing chamber from the atmosphere,
After passing through the gas replacement container, the processing can be performed in the processing chamber.

(Operation) When a fluid is introduced into the fluid containing means at the time of gas replacement, the fluid containing means secures a space inside the container to be replaced with gas. Therefore, the volume in the container to be replaced with gas is reduced, the gas replacement speed can be increased, and the working time of gas replacement can be shortened.

In particular, if such a fluid storage means is arranged in a dead space where the flow of the gas to be replaced is poor at the time of gas replacement, not only the volume of the container is reduced but also the dead space at the time of gas replacement. Since the effect is also exerted for the solution, the gas replacement speed can be further improved.

Further, in order to more preferably carry out the present invention, for example, in the case of a container having a rectangular cross section, a film that can be surface-contacted on its diagonal line, gas is introduced so as to abut on the diagonal line at the time of gas replacement. In this way, if the container is occupied by the fluid storage means, not only the dead space portion,
The space inside the container to be replaced with gas can be occupied by the space of the fluid storage means, and the replacement of gas can be completed.

(Example) Hereinafter, an example in which the present invention is applied to a gas replacement step of an N2 glove box of a liquid phase epitaxial growth apparatus will be specifically described with reference to the drawings.

First, the outline of the N2 glove box will be described with reference to FIG.

This N2 glove box 10 has a width of 3600 mm, a height of 590 mm,
This is a substantially rectangular parallelepiped housing having a depth of 750 mm, and is entirely formed of a transparent member such as an acrylic material.

This box 10 has a bottom surface 10a, a front surface 10b, a back surface 10c,
A right side surface 10d, a left side surface 10e, and a partly inclined upper surface 10f are provided. A front surface 10b, a rear surface 10c, an inclined surface of the upper surface 10f, and a right side surface 10e are provided with a door 11 that can be opened and closed.
Note that a manifold 12 having a seal flange 13 connected to a reaction tube for performing liquid phase epitaxial growth is connected to the left side surface 10e.

The area having the door 11 formed on the front surface 10b is
It is a pass box 14 for loading a boat,
Since this pass box 14 is opened when taking in and out the hoat, it is separated from the other N2 glove box 10 by the inner door 14b which can be opened and closed by the inner wall 14a, and it is possible to execute N2 purge independently. Has become.

In order to perform a manual operation in the N2 glove box 10, a plurality of glove holes 16 are arranged on the front surface 10b at a distance from each other. Such a glove 18 is attached. The globe 18 is formed of a flexible member having a low gas permeability, such as butyl rubber.

Inside the N2 glove box 10, a longitudinal boat loader device 20 for loading and unloading a graphite boat into and from a reaction tube (not shown), for example, a vertically movable tray station for setting a boat in the boat loader device 20
22, an up / down switch 24 of the tray station 22, a work table 25 and the like are arranged.

In order to keep the inside of the N2 glove box 10 in the N2 gas atmosphere at all times, for example, the lower surface 5b of the front surface 10b is used.
An N2 gas inlet 26 is provided at each location, and N2 gas outlets 28 are provided at, for example, five locations above the rear surface 10c.

The reason for performing IN of N2 gas from the lower part of the box 10 and discharging it from the upper part of the box 10 as described above is as follows.
H2, the carrier gas during the process, is a seal flange
This is for the purpose of promptly discharging when leaking from the 13 into the N2 glove box 10, and H2 with a low density is
Since it stays in the upper part of 10, it is configured as described above. However, the present invention is not limited to such a method, and for example, from the viewpoint of reducing the rise of dust due to the introduction of N2 gas, a configuration reverse to the above can be adopted.

The supply and discharge of such gas are realized by a piping system as shown in FIG. 4, and the N2 supply side valve V into the N2 glove box 10 and the pass box 14 is opened, and the discharge side valve V , And the dew point meter or the oxygen analyzer 29 can control the moisture in the gas and measure the oxygen concentration in the gas.

Next, a configuration for improving the gas replacement speed in the N2 box 10 will be described. As shown in FIG. 1 (A), the box 10 is composed of a corner portion of a wall surface, for example, a front surface 10b and a bottom surface 10a. The ballast film 30 is arranged at the corner. Then, a ballast port 32 capable of introducing and discharging a ballast gas is arranged inside the ballast film 30 and the wall surfaces 10a and 10b, and a ballast valve 34,
The ballast vessel pressure gauge 36 is connected. Each of the above members is an example of the fluid storage unit of the present invention.

Such a fluid accommodating unit is arranged in each position in the box 10 that serves as a dead space for the flow of the N2 gas. In particular, when it is arranged at each part of the bottom surface 10a and the front surface 10b, it may be arranged at each region between the N2 gas inlets 26, and the corner having the gas outlet 28 may be similarly arranged.

 Next, the operation will be described.

In the N2 glove box 10, since the atmosphere is mixed in the box 10 at the time of the initial start-up of the apparatus, after the main tenth, etc., it is necessary to perform a gas replacement to reduce the oxygen concentration to a certain value or less by N2 purging. There is.

Therefore, the supply side valve V is opened, and the discharge side valve V is also opened, so that the N2 gas is introduced into the box 10 and exhausted at the same time to execute the N2 purge.

Then, the N2 gas introduced into the box 10 from the plurality of gas inlets 26 arranged on the lower side of the box 10 flows through the box through the plurality of gas outlets 28 arranged at the upper end thereof. It will be exhausted. At this time, even if the number of the gas inlets 26 and the gas outlets 28 is increased, a dead space in which the N2 gas is difficult to reach occurs in the N2 glove box 10, and thus the oxygen concentration is reduced below a certain level in Aichi. The replacement speed was slow and required a considerable number of working hours. Therefore, in this embodiment, in order to eliminate such a region serving as a dead space, the film 30 shown in FIG. 1A is changed from a solid line to a broken line.

That is, when the ballast gas valve 34 is opened and the ballast gas is introduced into the sealed area between the ballast film 30 and the inner wall of the box 10, the ballast film 30 is changed from the solid line state in FIG. It moves to the state and acts to push the gas at the corners of the box 10 inward. At this time, it is necessary to set the indicated value of the ballast container pressure gauge 36 to be higher than the supply pressure of the N2 gas.

By setting to such a state, dead space especially at the corner of the box 10 is eliminated, and the flow of N2 gas reaches the entire area of the box 10, so that the gas replacement speed is significantly increased compared to the conventional case be able to.

Further, by pasting the ballast film 30 inside the box 10, the gas replacement volume of the box 10 is also reduced, which also enables the gas replacement speed to be improved.

After the gas replacement in the above state is performed for a predetermined time, the supply pressure of the ballast gas is made lower than the supply pressure of the N2 gas, so that the ballast film 30 is changed by the pressure difference to the state shown by the broken line in FIG. , So that the initial state can be restored. At this time, since the corners of the box 10 have been sufficiently gas-replaced, the oxygen concentration in the box 10 can be maintained at a desired value.

As described above, according to the apparatus of the present embodiment, the gas replacement speed can be greatly improved as compared with the related art.
By shortening the time of the gas replacement work, which has been required for about a week, the operation rate of the apparatus can be increased, and the supply amount of N2 gas per unit time can be reduced as compared with the conventional case.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

For example, a sufficient effect can be obtained by arranging the fluid containing means at least in the dead space region of the flow of the replacement gas as in the above-described embodiment. In the case where does not exist, the configuration shown in FIG. 1 (B) can be adopted.

As shown in the figure, the stretchable ballast films 41 and 42 are arranged so as to be in surface contact with each other on a diagonal line of a box 50 constituting a rectangular parallelepiped container.
It is arranged so as to be in close contact with the inner wall of 50b, while the ballast film 4
2 is disposed so as to be in close contact with the inner wall of the bottom surface 50c and the left side surface 50d. A gas inlet 51, a supply valve 52 and a pressure gauge 53 are arranged at the upper end of the left side face 50d located above the diagonal, and a gas outlet 54 and a discharge side valve 55 are arranged at the lower end of the right side face 50b. I have.

Further, a ballast port 56, a ballast valve 57, and a pressure gauge 58 are provided on the upper surface 50a and the lower surface 50c, respectively.

When performing gas replacement with the gas replacement device having the above configuration,
First, the ballast valve 57 is opened, and a ballast gas is introduced from the ballast port 56 in order to bring the ballast films 41 and 42 in close contact with the inner wall of the box 50 into diagonal surface contact. At this time, by closing the N2 gas introduction valve 52 and opening the discharge valve 55, the gas in the box 50 is discharged through the gas outlet 54 by the surface contact of the ballast films 41 and 42. Become.

Next, the N2 gas is introduced into the box 50 by opening the N2 gas introduction valve 52 and closing the discharge side valve 55. Here, by setting the relationship between the indicated value P1 of the pressure gauge 52 for the replacement gas and the indicated value P of the pressure 58 for the ballast gas to be P1> P2, the ballast gas in the ballast films 41 and 42 has a pressure difference. Discharged through the ballast port 56 for the ballast membrane
41 and 42 are restored to the solid line state in close contact with the inner wall of the box 50. Then, the inside of the box 50 is filled with the N2 gas as the replacement gas. Note that by repeating the above operation a plurality of times as necessary, gas replacement with oxygen or the like reduced to a desired value or less can be performed.

It is also possible to connect the same dew point meter or oxygen analyzer as in the first embodiment to the N2 gas discharge system.

If such an implementation method is adopted, the ballast films 41, 42
Can occupy the inside of the box 50 by the ballast container formed by the above. In this process, there is an effect that all the remaining gas in the box 50 can be exhausted, and the gas replacement speed can be further increased as compared with the first embodiment. Becomes

The fluid containing means for improving the gas replacement speed is not necessarily composed of a ballast film and a box wall surface, and may be a closed vessel itself such as a balloon, and a container that does not generate dead space. In the case of (1), the gas replacement volume is reduced by arranging this, and this action can contribute to improvement of the gas replacement speed. Therefore, the arrangement is not necessarily limited to the dead space.

Further, the ballast film does not necessarily need to be made of a stretchable material, and the medium introduced into the ballast film is not limited to gas, but may be a fluid.
Further, N2 gas is an example of the replacement gas, and other various gases can be employed depending on the replacement purpose.
In addition, the present invention can be particularly preferably practiced with respect to a flexible material container in which high vacuum cannot be applied, but the present invention is not limited to this, and can be applied to various containers requiring gas replacement.

In the above embodiment, an example in which the present invention is applied to a liquid phase epitaxial apparatus has been described.
It is also effective when applied to a semiconductor processing step such as a heat treatment furnace such as a diffusion furnace or an oxidation furnace or an etching apparatus.

[Effects of the Invention] As described above, according to the present invention, even if the container to be replaced with gas is a container having a relatively flexible structure without proof against internal and external pressures, it is possible to secure a space in the container. By arranging the fluid storage means, the gas replacement speed can be improved. In particular, by arranging the fluid accommodation means in the dead space of the gas flow, a remarkable effect can be achieved in improving the replacement speed.

[Brief description of the drawings]

1 (A) and 1 (B) are schematic explanatory views for explaining a main part of a gas replacement device to which the present invention is applied, and FIG. 2 is for explaining an N2 glove box to which the present invention is applied. 3 (A) is a front view, FIG. 3 (B) is a plan view, FIG. 3 (C) is a view along arrow AA, FIG. 3 (D) is a right side view, and FIG. FIG. 4 is a schematic explanatory diagram for explaining a working glove, and FIG. 4 is a schematic explanatory diagram for explaining a supply system and a discharge system of a replacement gas. 10,50… Gas replacement container, 30,41,42 …… Ballast membrane, 32,56 …… Ballast port, 34,57 …… Ballast valve.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location H01L 21/208 H01L 21/208 Z 21/22 501 21/22 501S 21/31 21/31 E

Claims (2)

(57) [Claims] When a gas in a container to be gas-replaced is replaced, the gas is disposed in a fluid storage means which is disposed at a predetermined position in the container and whose volume increases in the container by introducing a fluid. A gas replacement method comprising the steps of introducing a fluid, exhausting gas in the container, and performing gas replacement. 2. When the object to be processed is processed in the processing chamber, the object is placed in the gas replacement container before being loaded into the gas replacement container disposed between the atmosphere and the processing chamber. Discharging the gas in the gas replacement container by introducing a fluid into the filled fluid storage means and expanding the volume of the fluid storage means in the gas replacement container; A step of introducing an inert gas at a pressure higher than the introduction pressure of the fluid introduced into the fluid storage means, and thereafter, subjecting the object to be treated to the treatment chamber via the gas replacement container. And carrying out the treatment of the object to be processed.