JPH10238470A - Liquid feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent contamination due to particles so as to supply clean liquid to a next process by slightly deforming a variable, movable wall defining a handling liquid space of a variable capacity defined between the movable wall and a fixed wall having a handling liquid passage hole formed thereat by means of a finely moving mechanism so as to feed out handling liquid. SOLUTION: In operating a liquid feeder, first, a constant rate pump 44 is stopped, and then, an opening/closing valve 48 on a return pipeline 42 in an operating system and an opening/closing valve 32 on an inlet pipeline 28 in an liquid feeder system are opened while an opening/closing valve 34 on an outlet pipeline 30 is closed. Pressurizing gas is supplied from a liquid raw material tank 25, so that a liquid raw material is allowed to flow into a handling space 18 through a handling liquid passage hole 22 formed at an upper housing 14. At this moment, an operating liquid space 20 is contracted via a diaphragm 12, so that operating fluid is discharged via the return pipeline 42 until the diaphragm 12 reaches the lower face of the operating liquid space 20. Subsequently, the opening/closing valves 48, 32 are closed while the opening/ closing valve 34 is opened, and then, the operating fluid is allowed to flow out into the operating space 20 by the constant rate pump 44 to push up the diaphragm 12, thereby discharging the liquid raw material from the outlet pipeline 30 to an atomizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid supply apparatus, and more particularly to a liquid supply apparatus suitable for use in a thin film vapor deposition apparatus for vapor-depositing a high-dielectric or ferroelectric thin film on a substrate. .

[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. As a dielectric thin film used for manufacturing such a large-capacity element, tantalum pentoxide (Ta ₂₎ having a dielectric constant of about 20 is used.
O ₅ ) thin film, or barium titanate (BaTiO ₃ ) or strontium titanate (SrTi) having a dielectric constant of about 300
Metal oxide thin film materials such as O 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. As a gas source of the organometallic compound, for example, in the case of a metal oxide film of barium strontium titanate, Ba, Sr, Ti or a compound thereof is a DPM (dipivaloylmethane) compound, and these are used as an organic solvent (for example, Hydrafuran (hereinafter T
HF) etc.), a plurality of liquid materials dissolved in a predetermined ratio are uniformly mixed in advance at a predetermined ratio, and the mixture is sent to a vaporizer to be vaporized.

[0004] Such a mixed liquid raw material has a characteristic that it is liable to be deteriorated even when it is kept in a sealed state, and it is not desirable that the mixed liquid raw material flow into the liquid feed pipe. In particular, if heated or brought into contact with air, particles are generated and the quality of film formation is reduced. Therefore, it is desirable that the raw materials once mixed not only be stored in a stable state but also be used up quickly. Also,
In a film forming apparatus, it is desired to adjust a flow rate from a minute flow rate to a large flow rate in accordance with the process. Therefore, it is preferable that a liquid sending device for sending a raw material can perform a strict flow rate adjustment.

Conventionally, a metering pump capable of controlling a minute flow rate has been developed. This has parts that slide on each other like a piston and a cylinder or a bearing of a rotary shaft of a rotary pump, and a sealing member is attached to these parts.

[0006]

However, when a liquid material is fed using such a conventional metering pump, the following problems occur. Since the sliding part of the pump is in direct contact with the liquid, the liquid is liable to be contaminated by particles generated here. The pump is liable to break down in the sliding portion, and in the case of repair or maintenance, the liquid comes into contact with the atmosphere and deteriorates, thereby contaminating the entire flow path. There is a pulsation to alternately operate the reciprocating cylinder, diaphragm, bellows and the like.

[0007] In view of the above, the present invention does not directly contact the sliding portion with the liquid, so that it can be supplied to the next step in a clean state while preventing contamination by particles, and repair and maintenance can be performed. An object of the present invention is to provide a liquid feeding device that is easy.

[0008]

According to a first aspect of the present invention, there is provided a fixed wall having a handling liquid flow hole, and a deformable movable wall forming a variable volume handling liquid space between the fixed wall. ,
A fine movement mechanism for minutely deforming the movable wall. As a result, the volume of the handling liquid space is changed due to the deformation of the movable wall, and the handling liquid is sent out.
The handling liquid can be supplied to the next step in a clean state without coming into contact with the sliding portion.

According to a second aspect of the present invention, a working fluid space is formed on a side of the movable wall opposite to the handling liquid space, and the fine movement mechanism sends a working fluid to the working fluid space. The liquid feeding device according to claim 1, wherein: This makes it possible to supply the handled liquid to the next step in a clean state without contacting the sliding portion by using an appropriate external liquid sending means. The movable wall in this case can be appropriately used as long as the movable wall is deformable by itself, such as a flexible diaphragm or a bellows, and has no sliding portion.

A third aspect of the present invention is the liquid feeder according to the second aspect, wherein the working fluid is an incompressible fluid. According to a fourth aspect of the present invention, there is provided the liquid feeding device according to the second aspect, wherein the liquid sending means is a metering pump. A metering pump capable of controlling a very small amount of flow with high accuracy is commercially available, and by using this, a liquid can be sent with high flow control accuracy.

According to a fifth aspect of the present invention, there is provided the liquid supply apparatus according to the second aspect, wherein the handled liquid space and the working fluid space are formed substantially symmetrically. The invention according to claim 6 is the liquid transfer device according to claim 2, wherein the inner surface of the fixed wall is formed in a shape along the deformation of the diaphragm.

According to a seventh aspect of the present invention, there is provided the liquid feeding apparatus according to the first aspect, wherein the fine movement mechanism has an external drive device for mechanically deforming the movable wall. This makes it possible to simplify the configuration of the apparatus and to send the handled liquid without contacting the sliding portion.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. This liquid sending device sends a liquid source to a vaporizer in order to generate a vaporized source used for a thin film vapor phase growth device, for example.

This apparatus includes a housing 10 having a slightly flat space inside, and a diaphragm 12 (movable wall) which vertically partitions the internal space of the housing 10. The housing 10 has a substantially symmetric upper housing 14.
The (fixed wall) and the lower housing 16 are joined by an appropriate method with the diaphragm 12 interposed therebetween, thereby forming two liquid-tight spaces inside. That is, the upper housing 14 and the diaphragm 1
A space between the lower housing 16 and the diaphragm 12 is a working fluid space 20 for storing an incompressible working fluid.

The upper housing 14 is provided with a handling liquid flow hole 22 through which the handling liquid flows in and out.
4 is connected. The liquid supply pipe 24 is branched into an inflow pipe 28 connected to the liquid raw material tank 26 and an outflow pipe 30 connected to a vaporizer (not shown), and includes on-off valves 32 and 34, respectively. On the other hand, a working fluid hole 36 for allowing the working fluid to flow into and out of the working fluid space 20 is formed in the lower housing 16, and a working system pipe 38 is connected to the working fluid hole 36.

The operating system pipe 38 is branched into a discharge pipe 40 and a return pipe 42. The discharge pipe 40 is connected to a discharge port of a metering pump 44, and a suction port of the metering pump 44 is connected to a working fluid tank 46. Have been. Also, return pipe 4
2 is connected to a working fluid tank 46 via an on-off valve 48. In the case where the raw material liquid easily permeates the diaphragm, it is desirable to use the same liquid as the solvent of the raw material liquid as the working fluid. If there is no permeation problem, a liquid such as water or silicone oil, which is most convenient for the pump for sending the working fluid, is selected.

The diaphragm 12 is formed of a resin or the like having appropriate characteristics, and an appropriate one is selected in consideration of a fluid to be used, such as a synthetic rubber or a soft Teflon-based one. As criteria for selection, the strength, elasticity, chemical compatibility with the handling liquid and working fluid, etc. are evaluated. As shown, the housing 10
Is vertically symmetrical with respect to a plane sandwiching the diaphragm 12, and is formed substantially flat. That is, the diaphragm 1
2 has an inner surface shape along the deformable shape.

The operation of the liquid feeding device configured as described above will be described. First, a step of filling the handling liquid space 18 with the handling liquid is performed. In this case, the metering pump 44 is stopped, the open / close valve 48 of the return pipe 42 of the operating system is opened, the open / close valve 32 of the inflow pipe 28 of the liquid feed system is opened, and the open / close valve 34 of the outflow pipe 30 is closed. I do. Then, a gas for pressurization (He or the like) is supplied from a pressurizing pipe 48 of the liquid material tank 26, and the liquid material flows into the handled liquid space 18 from the handled liquid flow hole 22 of the upper housing 14.

The working fluid space 20 is contracted by the pressurization by the pressurizing gas, and the working fluid is discharged through the return pipe 42. This filling step is usually performed when the diaphragm 12 is in the working fluid space 2.
The process is performed until the bottom surface of 0 is attached. In this step, the pressurizing force by the pressurizing gas is very small and short, so that the pressurizing gas hardly mixes into the liquid raw material, so that no trouble occurs in the subsequent steps.

Next, a step of sending a small amount of the handling liquid in the handling liquid space 18 to the vaporizer in the next step is performed. In this case, the on-off valve 48 of the return pipe 42 of the operating system is closed, the on-off valve 32 of the inflow pipe 28 of the liquid feed system is closed, and the on-off valve 34 of the outflow pipe 30 is opened, and the metering pump 44 is operated. Then, the working fluid flows into the working fluid space 20 from the working fluid hole 36 of the lower housing 16. This working fluid is the diaphragm 1
2 is pushed up, and the liquid raw material is discharged through the outflow pipe 30 toward the vaporizer.

In this step, the amount of liquid material discharged is the same as the amount of working fluid supplied to the working fluid space 20, and the flow rate of the liquid material is the same as the discharge flow rate of the metering pump 44. Therefore, if a pump capable of controlling the minute flow rate with high precision is used as the metering pump 44, the liquid material can be sent with high precision while controlling the minute flow rate. Further, the pulsation of the metering pump 44 is smoothed by the action of the diaphragm 12, and stable liquid feeding is performed.

In the initial stage of the liquid feeding step, the diaphragm 1
Although the thickness decreases due to the elastic deformation of 2, the error does not occur if the pressure becomes constant. Usually, there is no problem because the liquid material in the initial stage of liquid sending is discharged without being used. Further, since the volume of the handling liquid space 18 can be set to be appropriately large with respect to the used flow rate, it is possible to supply the raw material for a considerably long time by performing a single filling step.

In such a liquid sending device, since there is basically no sliding portion in contact with the handling liquid, there is no generation of particles from the sliding portion and a clean liquid can be sent. In addition, since there is no sliding portion, there is no possibility that the handling liquid is released to the air for the repair or maintenance of the portion and deteriorates. Further, since the liquid is sent by the movement of the diaphragm 12, the gas is hardly mixed into the liquid raw material as compared with the case where the liquid is directly pressurized.

In this embodiment, the housing 1
Since the shape of the inner surface of 0 is formed according to the deformed shape of the diaphragm 12, the diaphragm 12 is not partially subjected to stress, and the life is long. Further, since there is no dead zone, the whole is flat and stagnation does not easily occur, deterioration of the raw material is small.

In this embodiment, the diameter of the housing 10 is made relatively large and flat, and the shape change of the diaphragm 12 can be suppressed more than when the housing 10 is made vertically long. However, in this case, the housing 1
It is necessary to increase the thickness of the housing 10 in order to suppress the deformation of the housing 10. This is because when the housing 10 is deformed by pressure, a problem occurs in the controllability of the flow rate. Therefore, diaphragm 1
If a durable and highly durable material can be obtained as 2, it is better to reduce the diameter of the housing 10 and increase the volume by height.

FIG. 2 shows a liquid feeding device according to a second embodiment of the present invention. Corresponding parts are indicated by the same reference numerals. This uses a metal bellows 52 (bellows) instead of the diaphragm 12 in the above embodiment.
That is, the housing 50 is formed in a substantially cylindrical shape, and a cylindrical bellows 52 whose upper part is covered is mounted on the bottom surface of the housing 50 coaxially. The outside of the bellows 52 is the handling liquid space 18, and the inside is the working fluid space 20, and the pipes are connected to each other. As the material of the bellows 52, a material that does not chemically react with the handling liquid or the working liquid is used.

The operation of the liquid feeding apparatus of this embodiment is basically the same as that of the previous embodiment, and will not be described. Since the movable wall is made of metal as described above, the durability is higher than in the case of resin, and the device can be operated for a long time.

FIG. 3 shows still another embodiment in which the bellows 52 is driven by a drive mechanism. That is, an opening 54 is provided at the bottom of the housing 50 to open a portion that is a space for the working fluid, and a rod 58 having a tip fixed to the canopy 56 of the bellows 52 is inserted into the opening 54. A drive mechanism 60 for raising and lowering the rod 58 is provided on the base end side of the rod 58. This includes a motor 64 with a reduction mechanism 62 having a large reduction ratio, and a gear mechanism 66 for changing the rotation into a linear motion.
And the like, so that the rod 58 can be finely moved up and down. The operation of this embodiment is basically the same as that of the previous embodiment, and will not be described.

[0029]

As described above, according to the liquid supply apparatus of the present invention, the volume of the liquid handling space is changed by the deformation of the movable wall to discharge the liquid handling, so that the liquid handling comes into contact with the sliding portion. Therefore, it can be supplied to the next step in a clean state while preventing contamination by particles. In addition, the frequency of repair and maintenance is reduced, and the work is easy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a liquid feeding device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a liquid feeding device according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a liquid feeding device according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 housing 12 diaphragm (movable wall) 14 upper housing (fixed wall) 18 handled liquid space 20 working fluid space 22 handled liquid flow hole 36 working fluid flow hole 44 metering pump 50 housing 52 bellows (movable wall) 60 drive mechanism

Claims (7)

[Claims] 1. A fixed wall having a handling liquid flow hole, a deformable movable wall constituting a variable volume handling liquid space between the fixed wall, and a fine movement mechanism for minutely deforming the movable wall. A liquid sending device characterized by the above-mentioned. 2. A working fluid space is formed on the opposite side of the movable wall from the handling liquid space, and the fine movement mechanism is a liquid sending means for sending a working fluid to the working fluid space. The liquid sending device according to claim 1. 3. The liquid feeding device according to claim 2, wherein the working fluid is an incompressible fluid. 4. The liquid sending device according to claim 2, wherein the liquid sending means is a metering pump. 5. The liquid feeding device according to claim 2, wherein the handling liquid space and the working fluid space are formed substantially symmetrically. 6. The liquid feeding device according to claim 2, wherein the inner surface of the fixed wall is formed in a shape along the deformation of the diaphragm. 7. The liquid feeding device according to claim 1, wherein the fine movement mechanism has an external driving device that mechanically deforms the movable wall.