JPH10192682A - Mixed liquid supplying apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently mix a plurality of liquid materials even at low flow rates and supply the resultant mixture to the next process without requiring members having movable parts and sliding parts. SOLUTION: This mixed liquid supplying apparatus comprises a plurality of liquid storage tanks 2a, 2b, 2c, liquid sending means 11a, 11b, 11c, 12, 13a, 13b, 13c to send liquid raw materials 1a, 1b, 1c in a plurality of the liquid storage tanks at a prescribed distribution ratio, and a mixing chamber 10 to receive and mix the liquid raw materials from the liquid sending means and, in an upper part of the mixing chamber 10, a plurality of liquid supplying pipes communicating with the respective liquid sending means are opened and formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mixed liquid supply apparatus, and more particularly to a thin film vapor deposition apparatus for vapor-depositing a high dielectric or ferroelectric thin film such as barium titanate / strontium on a substrate. And an optimal mixed liquid supply device.

[0002]

2. Description of the Related Art In recent years, the degree of integration of integrated circuits in the semiconductor industry has been remarkably improved, and research and development of DRAMs from the current megabit order to the future gigabit order have been conducted. To manufacture such a DRAM,
A capacitor element that can obtain a large capacity with a small area is required. A tantalum pentoxide (Ta ₂ O ₅ ) thin film having a dielectric constant of about 20, instead of a silicon oxide film or a silicon nitride film having a dielectric constant of 10 or less, as a dielectric thin film used for manufacturing such a large-capacity element. Metal oxide thin film materials such as barium titanate (BaTiO ₃ ) having a dielectric constant of about 300, strontium titanate (SrTiO ₃ ), or a mixture thereof, such as barium strontium titanate, are promising.

[0003] When such a metal oxide thin film is vapor-phase grown on a substrate, one or a plurality of organometallic compound gas raw materials and an oxygen-containing gas are mixed with each other and mixed on a substrate heated to a certain temperature. I try to inject. For example, in the case of a metal oxide film of barium strontium titanate, the gas source of the organometallic compound is Ba, Sr, Ti or a compound thereof with a DPM (dipivaloylmethane) compound, which is converted into an organic solvent (eg, tetrahydrahydran). Franc (hereinafter, TH
F)), a plurality of liquid raw materials dissolved beforehand are uniformly mixed at a predetermined ratio in advance, and the mixed liquid is vaporized by a vaporizer.

As a mixed liquid supply device for uniformly mixing such liquid raw materials at a predetermined ratio, for example, as shown in FIG. 5, liquid raw materials 1a, 1b, and 1c are stored, respectively.
The first transport pipe 3 is provided in each of the liquid storage tanks 2a, 2b, 2c.
a, 3b, 3c are connected to each other, and the other ends of the transport pipes 3a, 3b, 3c are connected to a rotary valve 4.
b, 2c each liquid raw material 1a, 1 stored in
It is known that the liquid surfaces of b and 1c are pressurized, liquid materials are sequentially sent out, and supplied to the rotary valve 4.

The rotary valve 4 is configured to repeatedly rotate at a predetermined angle and stop for a predetermined time, and sequentially feed predetermined amounts of the liquid raw materials 1a, 1b, 1c in one cycle. The downstream side of the rotary valve 4 is connected to a pump 7 and a mixing chamber 8 via a transport pipe 6, and the mixing chamber 8 is further provided with the mixing chamber 8 and a vaporizer (not shown) in the next step.
And a mixed liquid transport pipe 9 for connecting the same. The mixing ratio of each liquid raw material is set by the ratio of the stop time of the rotary valve 4 at the opening of each transport pipe 3a, 3b, 3c, and the flow rate of the mixed liquid is determined by the pressing force of the pressurizing means 5 and the rotary valve. 4 is determined. As shown in FIG. 6, the liquid raw materials 1a, 1b, 1c are not completely mixed inside the transport pipe 6, but are completely mixed only after being guided into the mixing chamber 8.

[0006]

In the above conventional example, 1
If the cycle time is long, complete mixing may not be possible as described above, so it is necessary to ensure a certain rotational speed even at low flow rates. For this reason, the sliding portion of the rotary valve is worn and has a short life, or particles are generated to contaminate the liquid material.

A pump is provided for each storage tank without using a rotary valve, and the driving time of each pump is individually controlled so that the flow rate of each liquid raw material is measured and the mixing chamber is measured. Is also known. However, the apparatus itself and control are complicated, and the number of pumps having a sliding portion is increased, which does not lead to a reduction in generation of particles.

SUMMARY OF THE INVENTION In view of the above problems, the present invention has been made so that a plurality of liquids can be sufficiently mixed even at a low flow rate and supplied to the next step without using a member having a movable portion or a sliding portion. It is an object to provide a mixed liquid supply device.

[0009]

According to a first aspect of the present invention, there is provided a liquid storage device comprising: a plurality of storage tanks; and a liquid feeding means for feeding each liquid material in the plurality of storage tanks at a predetermined distribution ratio. A mixing chamber for receiving and mixing the liquid raw material from the liquid sending means, and a plurality of supply pipes respectively communicating with the respective liquid sending means are provided at the top of the mixing chamber with being opened. This is a mixed liquid supply device.

According to the present invention having the above-described structure, the liquid stored in each storage tank is passed through each liquid feeding pipe via the liquid feeding means, and then the opening end of the liquid feeding pipe is opened. Liquid into the mixing chamber as liquid droplets, and the liquid can be mixed with the liquid droplets. As a result, the liquid can be surely mixed with a relatively simple configuration, and the particles due to the existence of the sliding portion and the movable portion can be mixed. Can be eliminated.

According to a second aspect of the present invention, there is provided the mixed liquid supply apparatus according to the first aspect, wherein an inner diameter of the supply pipe is set to 0.3 mm or less. This makes it possible to control the minute flow rate with a small amount of the droplet to be dropped.

According to a third aspect of the present invention, the liquid sending means includes a pressurizing means for commonly pressurizing the inside of each of the storage tanks,
2. The mixed liquid supply device according to claim 1, further comprising a flow controller provided in each of the liquid feed pipes from each of the liquid storage tanks. The flow rate of each fluid flowing through each liquid feed pipe is individually controlled via a flow rate adjuster provided in each liquid feed pipe.

According to a fourth aspect of the present invention, in the mixed liquid supply apparatus according to the first aspect, the liquid sending means has a pressurizing means for individually pressurizing the inside of each storage tank. is there. Thereby, the force acting on the liquid surface of the liquid stored in each storage tank by each pressurizing means can be individually adjusted, and the flow rate of each liquid flowing through each liquid feed pipe can be individually controlled. it can.

According to a fifth aspect of the present invention, in the mixed liquid supply apparatus according to the first aspect, the opening ends of the supply pipes are arranged on substantially the same vertical line. By making the dropping positions almost the same, the mixing efficiency can be increased.

According to a sixth aspect of the present invention, there is provided the mixed liquid supply apparatus according to the first aspect, wherein the area of the open end of each of the supply pipes is smaller than the sectional area of the supply pipe. .
This makes it possible to further reduce the amount of droplets held by the surface tension, and further reduce the minimum controllable flow rate.

A second pressurizing means for pressurizing the inside of the mixing chamber with a gas and discharging the liquid in the mixing chamber may be provided.
Thus, the liquid level in the mixing chamber can be adjusted while adjusting the amount of the liquid after mixing.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. Here, three liquid storage tanks 2a, 2b, 2c for storing three kinds of liquid raw materials 1a, 1b, 1c respectively have, for example, an inner diameter of 0.5 mmφ or less, preferably 0.1 to 0.3 mm.
Liquid feed pipes 11a, 11b, 11c of about φ are connected with one end of which is below the liquid level of the liquid raw materials 1a, 1b, 1c. Each of these liquid feed pipes 11a, 11b, 11c is provided with a flow controller for individually controlling the flow rate, for example, a mass flow controller (MFC) 13a, 13b, 13c.
It further extends to the mixing chamber 10 and has an open end 1
Supply pipes 15a, 15b having 4a, 14b, 14c,
15c.

In each of the storage tanks 2a, 2b, 2c, as in the case of FIG. 5, the stored liquid raw materials 1a, 1b,
The liquid level of 1c is set to 3 kgf with an inert gas such as He.
A pressurizing means 12 is provided which pressurizes at a common pressure PG1 of about / cm ² G and sequentially sends out liquid raw materials. The flow controllers 13a, 13b, and 13c, for example, adjust the opening of a diaphragm or a valve by using thermal expansion of a piezoelectric element or a cylinder, and can perform precise control on the order of microns, and are in contact with liquid. No particles are generated because there is no sliding part in the part.

It is to be noted that, without using a liquid feed pipe having a uniform inner diameter over the entire length, only the inner diameter at the end of the liquid feed pipe on the mixing chamber side is, for example, 0.5 mmφ or less, preferably 0.1 mmφ or less.
As a matter of course, a fine hole having a diameter of about 1 to 0.3 mm may be formed so that a droplet may fall from the fine hole.

Open ends (open ends) 14a, 14b, 14c of the supply pipes 15a, 15b, 15c in the mixing chamber 10.
Are arranged on substantially the same vertical line and vertically displaced from each other, thereby increasing the mixing efficiency by making the points where the liquid raw materials 1a, 1b, 1c drop at the same position. In this example, the open ends 14a, 14b, 14c are:
As shown in FIG. 2, the end of the supply pipe 15a is tapered in a conical shape to form a tapered portion T to reduce the area of the distal end surface.
Thus, the amount of the liquid droplet held by the surface tension acting between the tip surface and the liquid is reduced, and the liquid can be uniformly mixed even if the liquid amount is minute.

As shown in FIG. 3, supply pipes 15a,
15b and 15c are cut diagonally to open end 1
The area of the end faces of 4a, 14b and 14c may be made large. In this case, the larger the angle of the inclination, the larger the area, and therefore the larger the droplet, so that it is preferable when the amount of use is large. Alternatively, when the distribution ratio of each liquid raw material is different, the opening end portions 14a, 1
If the areas of the end faces of 4b and 14c are changed, each droplet is dropped at the same timing, and the change in concentration in the mixing chamber 10 is reduced.

The mixing chamber 10 is a cylindrical container whose lower part is tapered as shown in the figure, and the capacity is determined according to the required supply amount. For example, at least the supply flow rate Xml / min To about Xml or less,
It is desirable that the time during which the sample 6 stays in the mixing chamber 10 be as short as possible, and at most be within 1 minute. In the mixing chamber 10, the surface of the mixed liquid 16 stored in the mixing chamber 10 is filled with 1 kgf of an inert gas such as He.
Pressure means 1 for applying pressure at a pressure PG2 of about / cm ² G
7 are provided. Further, a mixed liquid transport pipe 19 extending from below the liquid level of the mixed liquid 16 and connected to the next step such as a vaporizer 18 is provided.
Is provided with a flow controller 20 and a check valve 21 in order along the flow direction.

The operation of the thus-configured mixed liquid supply device will be described. In the state where, for example, about 0.1 cc of the mixed liquid 16 is present in the mixing chamber 10, the liquid raw materials 1a, 1b, and 1c whose flow rates are controlled by the flow rate controllers 13a, 13b, and 13c are opened as described above. Ends 14a, 14b, 14c
And supplied in the form of droplets. Thus, a small amount of liquid raw material can be mixed without using a member having a sliding portion or a movable portion.

The mixed liquid raw material 16 is pressurized by the second pressurizing means 17 and flows downstream, flows continuously in the mixed liquid transport pipe 19 and is sequentially supplied to the vaporizer 18. The flow rate of the mixed solution is controlled by the flow controller 20. The pressure of the second pressurizing means 17 is set so as to maintain the liquid level in the mixing chamber 10 at a constant level.

With the above configuration, the liquid raw materials 1a, 1a stored in the respective liquid storage tanks 2a, 2b, 2c are provided.
b, 1c are measured by the flow controllers 13a, 13b, 13c provided in the respective liquid feed pipes 11a, 11b, 11c, while the open ends 14a, 15b of the supply pipes 15a, 15b, 15c are being measured.
Drops 14b, 14c are dropped into the mixing chamber 10 as droplets, and the liquid raw materials 1a, 1b, 1c are mixed with the drop, and the mixed liquid 16 after the mixing is sequentially supplied to the vaporizer 18. it can.

FIG. 4 shows a second embodiment.
The points of this example different from the first embodiment are as follows. That is, in each of the liquid storage tanks 2a, 2b, 2c,
Liquid raw material 1 stored in liquid storage tanks 2a, 2b, 2c
Pressurizing means 30a, 30b, 30c are provided for individually controlling the pressure applied to the liquid levels of a, 1b, 1c. Orifices 31a, 31b, 31c are provided in the vicinity of the inlet of the mixing chamber 10 of each of the liquid sending pipes 11a, 11b, 11c, and a flow controller for each liquid sending pipe is omitted.

In this example, the flow rate of the liquid raw material 1a is similarly increased by the pressure difference PG11-PG2 between the pressure PG11 by the pressurizing means 30a and the pressure PG2 by the second pressurizing means 17. Pressure P by pressure means 30b
G12 and the pressure difference P between the pressure PG2 by the second pressing means 17
By G12-PG2, the flow rate of the liquid raw material 1c is individually controlled by the pressure difference PG13-PG2 between the pressure PG13 by the pressurizing means 30c and the pressure PG2 by the second pressurizing means 17. Therefore, the mixing ratio can be adjusted or appropriately changed. Instead of providing an orifice in the liquid sending pipe, a part of the liquid sending pipe itself may be thinned.

[0028]

As described above, according to the present invention,
The liquid stored in each liquid storage tank is dropped into the mixing chamber as liquid droplets from the opening end of the supply pipe in the mixing chamber via the liquid sending means, whereby a small flow rate to a wide flow rate range can be achieved with a relatively simple configuration. The liquid can be surely mixed at. In addition, since there is no sliding portion or movable portion, the generation of particles due to this is eliminated, and a high-quality mixed liquid can be supplied smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of a mixed liquid supply device according to a first embodiment of the present invention.

FIG. 2 is an enlarged front view showing an open end of a supply pipe according to the embodiment of FIG. 1;

FIG. 3 is a diagram showing a modification of FIG. 2;

FIG. 4 is a schematic diagram of a mixed liquid supply device according to a second embodiment of the present invention.

FIG. 5 is a schematic view of a conventional mixed liquid supply device.

FIG. 6 is a cross-sectional view for explaining a state of a fluid flowing in a transport pipe after the rotary valve.

[Explanation of symbols]

 1a, 1b, 1c Liquid raw material 2a, 2b, 2c Liquid storage tank 10 Mixing chamber 11a, 11b, 11c Liquid feed pipe 12, 30a, 30b, 30c Pressurizing means 13a, 13b, 13c, 20 Flow controllers 14a, 14b, 14c Open end 15a, 15b, 15c Supply pipe 17 Second pressurizing means 18 Vaporizer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Murakami 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation

Claims (6)

[Claims] 1. A plurality of liquid storage tanks, and liquid sending means for sending each liquid raw material in the plurality of liquid storage tanks at a predetermined distribution ratio,
A mixing chamber for receiving and mixing the liquid raw material from the liquid sending means, and a plurality of supply pipes each communicating with each of the liquid sending means are provided at an upper portion of the mixing chamber with openings. A mixed liquid supply device. 2. The mixed liquid supply device according to claim 1, wherein an inner diameter of the supply pipe is 0.3 mm or less. 3. The liquid feeding means includes a pressurizing means for commonly pressurizing the inside of each liquid storage tank, and a flow controller provided in a liquid feeding pipe from each liquid storage tank. The mixed liquid supply device according to claim 1, wherein 4. The mixed liquid supply device according to claim 1, wherein said liquid feeding means has a pressurizing means for individually pressurizing the inside of each storage tank. 5. The mixed liquid supply device according to claim 1, wherein the open ends of the supply pipes are arranged on substantially the same vertical line. 6. The mixed liquid supply device according to claim 1, wherein the area of the open end of each supply pipe is smaller than the cross-sectional area of the supply pipe.