JPS5848923A - High pressure oxidizer - Google Patents

Abstract

PURPOSE:To obtain a safe apparatus without any contamination by accomodating a water tank within the sub-pressure proof container, connecting it to the reaction vessel and supplying water to said reaction vessel while the pressure within said sub-pressure proof container is kept higher than that within the reaction vessel. CONSTITUTION:The main pressure-proof container 1 is set to a predetermied pressure P and an internal pressure of reaction tube 2 is set to P0 while an internal pressure of the sub-pressure proof container 5 is set to P1. Here, the respective pressure differences DELTAP0, DELTAP1 from the pressure P are set to the feedback type controllers 3, 9. In case a pressure condition is set as follow, namely, P<P0<P1, the pure water 6 is pressurizingly sent to the reaction tube 2 through a fine tube 7 by the relation of DELTAP1-DELTAP0, humidifying inside of the tube 2. When a value of DELTAP1-DELTAP0 is properly selected, amount of pure water to be supplied can be controlled easily, and in addition amount of water to be supplied can be changed by changing tube diameter of the fine tube 7 or by restricting flow path by providing a valve 11 at the intermediate portion. According to this structure, a high pressure pump is no longer necessary and a safe high pressure oxidizer can be obtained without generating contamination and any anxiety of explosion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure oxidation apparatus, and particularly to a humidification apparatus for creating a humidified atmosphere inside a reaction vessel.

A high-pressure oxidation bag is a device whose purpose is to form oxide km on the surface of a silicon substrate at a relatively low temperature and in a short time by heating a semiconductor substrate in a high-pressure humidified atmosphere. It is equipped with a humidifying means to create a humidified atmosphere.

Conventionally, the heating method used was to burn high-pressure hydrogen (H2).
Many were used to generate water vapor (H!o). This method has the advantage that it is easy to handle because the humidification source is a gas, and that high-purity H2O is obtained and there is no risk of contamination. However, since high-pressure hydrogen is used, there is a risk of explosion.

Therefore, in recent years, attempts have been made to use high-purity water as a humidifying source instead of high-pressure hydrogen.

This is because, for example, a high-pressure pump is used to forcefully pump high-purity water into a reaction tube (this is not as sudden as the explosion mentioned above, but the material of the high-pressure pump itself and the welded parts of the high-pressure pump Contamination may occur due to materials and processing methods, and it is not easy to prevent such contamination over a long period of time.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a safe high-pressure oxidation device that does not cause contamination.

The high-pressure oxidation apparatus of the present invention is characterized by comprising a water tank, an auxiliary pressure vessel that accommodates the water tank, a thin tube that communicates the water tank and the reaction vessel (f), and means for controlling the internal pressure of the pressure vessel (f). The purpose of the present invention is to provide a humidifying means formed by:

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

In the figure, 1 is a main pressure vessel made of metal, 2 is a reaction tube made of quartz housed in the main pressure vessel, and 3 is a feedback type gerator, which constitutes the main part A of the high-pressure oxidation apparatus. Further, 4 is a water tank made of quartz, 5 is an auxiliary pressure-resistant container that houses the water tank 4 inside and is made of metal such as stainless steel, 6 is high-purity water (hereinafter simply referred to as pure water), and 7 is a water tank whose one end is A thin tube 8 made of quartz, which is inserted into the pure water 6 stored in the water tank 4 and whose one end is connected to the reaction tube 2, holds the thin tube 7 and is connected to the inside of the main pressure vessel 1. 9 is a feedback type regulator; 10 is a feedback type regulator 9 that feeds the pressure inside the main pressure vessel 1;
Piping for feeding back to, 11 is pulp, 12
is a pipe, and the above constitutes a humidifier [B].

Among the above, the main part A accommodates the reaction tube 2 inside the main pressure vessel t.
This is no different from conventional high-pressure oxidation equipment (as is well known, this structure is designed to minimize the pressure difference between the inside and outside of the reaction tube 2 to prevent breakage or deformation of the reaction tube.

That is, the pressure P inside the main pressure vessel 1 is set to the predetermined pressure P inside the reaction tube 2.
The pressure selected between 0 and atmospheric pressure (practically a slightly lower pressure than Po) is set so that most of the difference between the reaction tube 2 internal pressure P0 and atmospheric pressure is borne by the main pressure capacity Wh1, and the reaction The load on the pipe 2 can be reduced. The reason why the internal pressure P6 of the reaction tube 2 is set higher than the internal pressure P of the main pressure vessel 1 is to prevent the atmosphere inside the main pressure vessel 1 from entering the reaction tube 2. A feedback type dfjL regulator 3 was chosen for this purpose, and it
The internal pressure P of the reaction tube 2 is based on the internal pressure P. is controlled so that it is always higher by a desired pressure difference ΔP0 due to P.

The humidifying device B provided in the main section A is intended to release the pure water 6 contained in the water tank 6 into the reaction tube 2 by pressure difference.

For this purpose, a secondary pressure vessel 5 is provided, which is connected to the main pressure vessel 1 in an airtight manner. A water tank 4 is installed inside the sub-pressure capacity SS, and pure water 6 is kept in it. A thin tube 7 is led out from this water tank '4 and connected to the reaction tube 2. This allows the inside of the water tank 4 and the inside of the reaction tube 2 to communicate with each other. Note 13
is a connecting end 14 made of a quartz tube led out from the reaction tube 2;
Shows the connection with. Further, the connecting opening of the pressure-resistant container 5 is sealed by a rubber plug No. 8 into which the thin tube 7 is inserted in an airtight manner.

This rubber stopper 8 airtightly blocks the main pressure vessel 1 and the sub pressure vessel 5, and also holds the thin tube 7. A desired high-pressure gas, for example, high-pressure nitrogen (Nm), is introduced into the sub-pressure vessel 5 via a pipe 12 by opening the pulp 11 . The pressure P□ in the auxiliary pressure vessel 5 is controlled by the feedback regulator 9 to a pressure 1Ii11 higher than the pressure P in the main pressure vessel 1 by a desired pressure difference ΔP1.

Next, the operation of the high pressure oxidation apparatus constructed as described above will be explained in detail.

First, the pressure P inside the main pressure vessel l is set to a predetermined pressure, for example, 10 [
υ〕G2 set. This is not shown in the figure, but the pressure gas (for example, nitrogen N) piping system connected to the main pressure vessel 1 is interposed with two ordinary regulators, and the regulator This can be done by setting the pressure.

Next, the pressure difference ΔP0 between the reaction tube 2 internal pressure P0, the auxiliary pressure vessel 5 internal pressure P, and the casting main pressure vessel P is determined. ΔP1 is set to 3.9G using a feedback type regulator. Note that ΔPG and P1 are as described above, po=p
+ΔP.

p, -p +ΔP1 and Δp, > Δpo, (ΔP0+ Δp, >o)
A value selected to satisfy the relationship, for example, a
P. 5 to 20 (Torr) *ΔP, approximately 0.5
(police).

With the above, the pressure in each part is controlled as desired, and P <
The relationship P, < Pl is maintained. Therefore, pure water 6 is Pl
Due to the pressure difference ΔP (that is, ΔP−ΔP, −ΔP0) between Po and Po, the reaction tube 2 is forced to be fed into the reaction tube 2 through the thin tube 7, and a humidified atmosphere can be created in the reaction tube 2.

In this humidifying device, the amount of pure water supplied into the repulsion tube 2 can be easily controlled. That is, it can be controlled not only by appropriately selecting the pressure difference ΔP, but also by making use of the fact that the thin tube 7 acts as a resistance to the flow of water, and by varying this resistance. The value of the above resistance is Ji'+? It can be varied by selecting the inner diameter of the tube 7, or by providing a valve in the middle of the thin tube 7 and restricting the flow path using this pulp.

As described above, in this embodiment, pure water is pumped into the reaction tube 2 by the pressure difference ΔP, and there is no need for an undesirable high-pressure pump as in the conventional example.

Further, since the pressure applied to the water tank 4 and the thin tube 7 only needs to be very small, both can be made of quartz without worrying about contaminating semiconductors. Therefore, the humidifying device of this embodiment is safe and easy to handle without the risk of contamination.

The present invention is not limited to the above-mentioned embodiments, but can be implemented with various modifications.

For example, the thin tube 7 may be led out from near the bottom of the side wall of the water tank 4.

Further, the arrangement position of the knitted pressure vessel 5 need not be limited to the upper part of the main pressure vessel 1 as in the above-mentioned embodiment, but may be placed at any position such as beside or diagonally above the main pressure vessel 1.

However, the relative height of the water tank 4 and the reaction tube 2, and the high pressure gas used is not limited to high pressure nitrogen; for example, the atmosphere inside the reaction tube 2 may be high pressure oxygen (02), or There is no need to specifically explain that the pressure control method can also be selected.

As explained above, the present invention provides a high-pressure oxidation device that is free from contamination, easy to handle, and safe.

[Brief explanation of the drawing]

The figure is a sectional view of essential parts showing an embodiment of the present invention, in which 1 is a main pressure vessel, 2 is a reaction tube, 4 is a water tank, 5 is a sub pressure vessel,
6 indicates high purity water, 7 indicates a capillary, and B indicates a humidifier.

Claims (1)

[Claims] It comprises a reaction vessel for accommodating an object to be electrified, a main pressure vessel for storing the reaction vessel therein, and a means for humidifying the atmosphere inside the reaction vessel, and the pressure inside the reaction vessel and the main pressure vessel is controlled. Adhering to a high-pressure oxidizer that can control the desired pressure,
The humidifying means includes a water tank, a sub-pressure vessel for accommodating the water tank, a thin tube communicating the water tank and the reaction vessel, and means for controlling the internal pressure of the sub-pressure vessel, and the sub-pressure vessel A high-pressure oxidation apparatus characterized in that the internal pressure is made higher than the internal pressure of the reaction vessel so that water is supplied from the water tank into the reaction vessel.