JPH05283340A - Liquid raw material gasification supply device - Google Patents

Abstract

PURPOSE:To enable stable supply of raw gas of an amount required for mass production of high determination accuracy by providing a heating means which enables temperature control to each of a container, a mass flow controller, a valve and a piping connecting them. CONSTITUTION:A container 1 containing liquid raw material 2 is formed to a vertical airtight hollow tube, and a heating means 3 is provided to a periphery of the container 1 and is constituted to enable temperature indication and temperature adjustment through a temperature indication controller 4. A three-way valve 10, an MFC 11 and a two-way valve 12 are interposed one by one from the container 1 to a downstream. A heating means 13 is provided to a supply tube 9 which is constituted to enable supply of raw gas from the container 1 to a vapor reaction device to enable temperature indication and temperature adjustment through a temperature indication controller 14 provided in a proximity to the MFC 11, for example. A ratio between an inner diameter and an axial length of the container 1 is made 2.0 or more and a content volume of a vapor part 21 is set 60 or more times a consumption gas amount; otherwise, operation in a vapor reaction device can not be carried out stably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to the production of thin film circuits using liquid raw materials (TEOS, SiCl ₄ , TiCl ₄ , high-purity water, etc.) in the production of semiconductor devices, optical fibers, coating tools, etc. The present invention relates to a liquid source vaporization and supply device capable of vaporizing this liquid source and stably supplying a large amount to the film forming apparatus in a precisely controlled state.

[0002]

2. Description of the Related Art Chemical vapor deposition (CV) has been used as a means for forming a thin film in the technical field of semiconductors, for example.
D: Chemical Vapor Deposition) is commonly used. A thin film is formed by this CVD by chemically reacting a reaction gas on a heated substrate, but monosilane (SiH ₄ ) which is a reaction gas that has been conventionally used is inferior in step coverage. In recent years, TEOS (tetraethoxysilane), which has excellent step coverage, has been used in place of monosilane.

However, since TEOS is liquid at room temperature, it is necessary to supply it in a vaporized state in order to apply it to CVD. Conventionally, bubbling has been used as a means for vaporizing the liquid TEOS. In the bubbling method, for example, a liquid raw material is contained in a bubbler provided in a constant temperature bath, a carrier gas is blown through an introduction pipe opened in the liquid raw material, and the liquid raw material is vaporized by bubbling.

In the bubbling method as described above, not only a large flow rate cannot be obtained because the evaporation amount of the liquid raw material is small, but also the flow rate is unstable and the pressure fluctuation is large. There is a drawback that the film forming characteristics are unstable. In order to eliminate such drawbacks, a liquid raw material is flow-controlled in a liquid state through a mass flow controller (mass flow meter, hereinafter referred to as MFC), and then vaporized in a vaporization chamber equipped with a heating means (for example, Japanese Patent Laid-Open No. H11-242242). 3-12
No. 6872), or a container for containing a liquid raw material, an MFC, various valves, and piping for connecting these to a thermostatic chamber, and controlling the flow rate of the vaporized raw material at a temperature higher than room temperature (for example, actual Kaihei 1). -83432 and Japanese Patent Application Laid-Open No. 2-253612) have been proposed.

[0005]

However, in the former means for controlling the flow rate in the liquid state, the quantitative accuracy is lower than that in the gaseous state, it is difficult to obtain a reaction gas having a constant concentration, and the film forming characteristics are unstable. There is a problem that

On the other hand, in the latter means for accommodating the entire apparatus in the constant temperature bath, not only is the overall size of the apparatus increased, but even if a means for forced convection in the constant temperature oven is also used, Is difficult to keep constant, temperature control of the MFC which requires strict temperature control becomes difficult, and there is a problem in that the quantitative accuracy is also adversely affected. In addition, when using such a constant temperature bath, it takes time for the entire device to reach a predetermined temperature, and if the vaporized reaction gas leaks from the container or piping system, it is Explosion may occur or gas poisoning may occur, which is a safety issue.

In any of the above means, the ability to vaporize the liquid raw material is low, and for example for semiconductor devices, T
When EOS is used, it is 500 ml / min or less, and there is also a problem that the capacity is insufficient as a liquid raw material vaporization and supply device for mass production.

An object of the present invention is to solve the problems existing in the above-mentioned prior art, and to provide a liquid raw material vaporizer / feeder which has a high quantitative accuracy and can stably feed the raw material gas in an amount necessary for mass production. And

[0009]

[Means for Solving the Problems] To achieve the above object
In addition, in the present invention, the liquid raw material contained in the container is added.
Heat vaporizes and vaporizes the raw material gas into a valve or mass flow controller.
Gas phase reaction through the trawler and piping connecting them
In the liquid raw material vaporization supply device for supplying to the device, a container,
Mass flow controller, valve and connecting these
In addition to providing heating means that can control the temperature in each pipe,
In the container, the ratio of the axial normal length L to the inner diameter D is L / D ≧
2.0 is formed into an upright hollow cylindrical shape, and
The internal volume of the gas phase is V_T(Ml) V gas consumption_U(Ml
/ Second)_T≧ 60V _UAnd the technology
Adopted the automatic means.

In the present invention, when L / D is less than 2.0, the temperature distribution in the diametrical direction on the surface of the liquid raw material, that is, the evaporation surface becomes non-uniform, and the effective evaporation surface that contributes to evaporation is reduced, and the vaporization ability is decreased. Is reduced, which is inconvenient.

When V _T is less than 60 V _U , not only the internal volume of the gas phase portion becomes insufficient, the pressure fluctuation of the raw material gas becomes large, but also the operation duration time in the gas phase reaction device becomes short and the raw material gas becomes short. This is inconvenient because the gas cannot be stably supplied.

[0012]

With the above structure, the temperature distribution in the diameter direction of the evaporation surface in the container for containing the liquid raw material becomes uniform, the effective evaporation surface is sufficiently ensured, and the vaporization capacity can be sufficiently ensured. Further, since the inner volume of the gas phase portion in the container is sufficiently large with respect to the amount of consumed gas, it is possible to suppress the pressure fluctuation of the raw material gas supplied to the gas phase reaction device.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a structural explanatory view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a container for containing the liquid raw material 2, which is made of stainless steel such as SUS316 and SUS316L and is formed in an upright closed hollow cylindrical shape. Reference numeral 3 is a heating means, which is provided around the container 1 and is configured to be capable of temperature indication and temperature adjustment via a temperature indication controller 4. 5
Is a level adjusting means, and 6 is a pressure instruction adjusting means, which are respectively interposed in the container 1 and configured to be able to adjust the liquid level of the liquid raw material 2 in the container 1 and the pressure in the container 1 to be adjustable.

Next, 7 is a replenishment pipe, which is provided with a two-way valve 8 and is arranged between a replenishment source (not shown) of the liquid raw material 2 and the container 1. The opening of the supply pipe 7 in the container 1 is preferably provided near the bottom of the container 1. Reference numeral 9 denotes a supply pipe, which is arranged between the upper portion of the container 1 and a gas phase reaction device (not shown), and is provided with a three-way valve 10, an MFC 11 and a two-way valve 12 in this order from the container 1 toward the downstream side. It is interposed so that the raw material gas can be supplied from the container 1 to the gas phase reactor. The supply pipe 9 is provided with a heating means 13 so that the temperature can be controlled and the temperature can be controlled, for example, via a temperature controller 14 provided near the MFC 11.

A purging gas supply pipe 15 is arranged between a supply source (not shown) of an inert gas such as N ₂ gas and the replenishment pipe 7 and the supply pipe 9, and is a check valve. 16, a three-way valve 17 and a two-way valve 18 are interposed, and a purge gas is supplied to the supply pipe 7, the supply pipe 9 and the container 1.
It is configured so that it can be selectively supplied. Next, a discharge pipe 19 is provided so as to branch from the supply pipe 9 in the middle portion of the MFC 11 and the two-way valve 12, and the two-way valve 20 is interposed.
A heating means 22 similar to that provided in the supply pipe 9 can be provided in a part of the supply pipe 15 and the discharge pipe 19.

The operation of the above arrangement will be described below. First, it is necessary to purge the air in each component before starting the apparatus. In this case, the two-way valves 8 and 12 are closed, the two-way valve 20 is opened, and the purge gas is introduced from the supply pipe 15 and discharged to the discharge pipe 19. As a result, the air in each component is purged outside the device and replaced with the inert gas. After the purging work is completed, the two-way valves 18 and 20 are closed.

Next, the two-way valves 8 and 12 are opened to introduce a predetermined amount of the liquid raw material 2 into the container 1 through the replenishing pipe 7, and the heating means 3 heats and vaporizes it. The gas phase portion 21 formed in the container 1 has an internal volume of approximately 50% of the internal volume of the entire container 1.
Is preferably formed. The raw material gas vaporized in the container 1 is supplied to the gas phase reaction device (not shown) from the two-way valve 12 while being controlled to a predetermined flow rate by the MFC 11 via the supply pipe 9.

The temperature and pressure of the raw material gas are controlled to predetermined values by the pressure indicator adjusting means 6 and the temperature indicator controllers 4 and 14. Further, the amount of the liquid raw material 2 in the container 1 is controlled by the level adjusting means 5 and is replenished from the replenishing pipe in a timely manner so that a predetermined level range can be maintained.
Further, the supply of the raw material gas may be carried out under normal pressure or higher pressure, but it may also be carried out under reduced pressure below normal pressure according to the characteristics or properties of the liquid raw material 2. is there.

Next, the result of changing the ratio of the inner diameter D of the container 1 to the axial length (internal dimension) L by the apparatus having the above-mentioned structure will be described. In this case D = 100mm
In addition to using TEOS as the liquid raw material 2,
The temperature of the liquid raw material 2 in the container 1 is 110 ° C, and the vapor pressure is 14
The temperature of the liquid raw material 2 replenished from the replenishment pipe 7 was 5 Torr and 20 ° C. Further, the vapor phase portion 21 formed in the container 1
The inner volume of the container was about 30% of the total inner volume of the container 1.

Table 1 shows the internal volume of the gas phase portion 21 when the axial length L of the container 1 is changed, and the state of temperature drop and pressure drop when replenishing the liquid raw material. The value of the amount of raw material gas generated (m
1 / min) is the value of the internal volume of the gas phase portion 21 in the container 1 (ml)
It corresponds approximately to.

[0021]

[Table 1]

As is apparent from Table 1, as the axial length L increases, the internal volume of the vapor phase portion 21 and the amount of raw material gas generated naturally increase. That is, the internal volume of the container 1 shown in FIG. 1 becomes large and the amount of heat transferred to the liquid raw material 2 increases. In general, for mass production in the field of semiconductor devices, a raw material gas generation amount of 500 ml / min or more is required. Therefore, No. 1 in Table 1 If it is other than 1, this requirement can be satisfied.

However, No. In No. 2, the temperature drop when the liquid raw material 2 was replenished was 9 ° C., and the temperature drop of the liquid raw material 2 in the container 1 was large, so the pressure drop of the raw material gas was also large. Therefore, it affects the film forming work in the vapor phase reactor. From this point of view, No.
No. 2 is not suitable for stable supply of raw material gas.
3-6 are preferable. That is, L / D ≧ 2.0 or more is preferable.

The internal volume of the vapor phase portion 21 is the amount of consumed gas (m
It is clear from experience that a stable work cannot be performed in the gas phase reactor unless it is set to 60 times or more of 1 / second). In recent years, the amount of consumed gas has been required to be 8 ml / sec, and the internal volume of the gas phase portion 21 must be 480 ml or more in order to cope with such an application. Therefore, No. 1 in Table 1 1 and No. 2 can't handle it.

In the above embodiment, since the vapor pressure of TEOS is extremely low at room temperature, it is effective to reduce the pressure inside the container 1 to increase the amount of evaporation, but if the degree of pressure reduction becomes too large, the gas phase reaction will occur. Since the introduction amounts of the raw material gas and the carrier gas in the entire piping system including the apparatus are reduced and a predetermined film forming action cannot be obtained, the degree of pressure reduction is preferably as small as possible. On the other hand, when the temperature rises, the vapor pressure of TEOS increases, so vaporization in a high temperature atmosphere is preferable.
Therefore, the three-way valve 1 to be inserted in the source gas supply pipe 9
It is preferable that the 0, MFC 11 and the two-way valve 12 have a high usable temperature, for example, 150 ° C. or higher.

In this embodiment, an example in which TEOS for a semiconductor element is used as the liquid raw material has been described.
In addition to this, the target liquid raw material can be applied to high-purity water and other organometallic compounds and metal compounds that exhibit a liquid phase at room temperature, and include, for example, the following. That is, TEAL (triethylaluminum), TEI (triethylindium), TMA
L (trimethylaluminum), TiCl ₄ (titanium tetrachloride), WF ₆ (tungsten hexafluoride), Ta (OC)
₂ H ₅ ) ₅ (tantalum alkyne), CCl ₄ (carbon tetrachloride), SiCl ₄ (tetrachlorosilane), SiH
Examples thereof include Cl ₃ (trichlorosilane) and TMPO (trimethoxyphosphoric acid).

[0027]

EFFECTS OF THE INVENTION Since the present invention has the constitution and operation as described above, the following effects can be obtained.

(1) The vaporization supply amount of the liquid raw material is 500 ml /
It is possible to shorten the film forming time for a member such as a large-sized substrate and the like, and it is possible to satisfy the requirements for mass production and to greatly improve the productivity.

(2) Since the liquid raw material is quantified in the vaporized state via MFC, the mixing ratio with the carrier gas can be set to an arbitrary concentration, and the pressure fluctuation can be suppressed to an extremely small range, so that a uniform and uniform film can be obtained. Thick films can be produced.

(3) Since it is not necessary to store the entire apparatus in a constant temperature bath, the rise time before the start of use is short, and even if gas should leak, it will be liquefied in a normal temperature atmosphere, so that it is highly safe.

[Brief description of drawings]

FIG. 1 is a configuration explanatory view showing an embodiment of the present invention.

[Explanation of symbols]

 1 container 3,13 heating means 11 MFC (mass flow controller)

Claims (1)

[Claims] 1. A liquid raw material vaporization supply device for heating and vaporizing a liquid raw material contained in a container and supplying the vaporized raw material gas to a gas phase reaction device through a valve, a mass flow controller and a pipe connecting them. , A mass flow controller, a valve, and a pipe connecting them are provided with heating means capable of controlling the temperature, respectively, and a ratio of an axial inner normal length L to an inner diameter D of the container is L.
/D≧2.0, formed into an upright hollow cylinder, and the internal volume of the gas phase portion in the container is V _T (ml) and the gas consumption is V
A liquid raw material vaporizer / feeder, wherein V _T ≧ 60 V _U when _U (ml / sec).