JPH11152571A - Liquid material vaporizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the wear of a sliding part of a plunger pump for delivering the fixed volume of a liquid material to a vaporizer while maintaining corrosion resistance so as to prolong the service life and maintenance and facilitate management by using PTFE mixed with carbon in a fibrous form as a sealing material in the sliding part. SOLUTION: A plunger 1 which is held sealed by a plunger seal 2 is put into and out of a pump chamber 4 bored at a pump head 5 by sliding in an arrow direction to vaporize the fixed volume of the liquid material contg. a volatile org. metal compd. of a thin-film material and to supply the vapor thereof to the vaporizer via a liquid inlet and outlet 6, 7 having check valves 8, 9. The PTFE prepd. by incorporating the carbon in the fibrous form therein is used as the sealing material of the sliding part 1a of the plunger seal 2 of the plunger pump described above. As a result, the carbon is mingled in the PTFE which is a base material having the excellent corrosion resistance in the state of entangling therewith. The dislodgment of the sealing material does not arise in spite of sliding and the wear resistance and lubricity of the plunger seal 2 are improved, by which the life is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid material vaporizing apparatus capable of suitably supplying a film forming liquid material in a semiconductor manufacturing apparatus, and more particularly to a sealing structure of a liquid feeding pump in the apparatus. .

[0002]

2. Description of the Related Art In the production of semiconductor devices, a process of forming a metal thin film on a substrate is indispensable.
(Physical vapor deposition) has been used.
VD (Chemical Vapor Deposition or Chemical Vapor Deposition), among which MOCVD (Metal Organic Chemical Vapor Deposition) has become popular. In this method, a volatile organic compound of a metal to be formed into a thin film, or a liquid obtained by dissolving it in a solvent (hereinafter, these are simply referred to as a liquid material) are vaporized and sent to the substrate surface in a vapor state, A thin film of a product is deposited by a reaction at the time of thermal decomposition. This method
It is said to be superior to the previous method in terms of film quality, film forming speed, step coverage at the step, and the like.

In a liquid material vaporizing apparatus for performing MOCVD, a plunger pump is often used as a pump for accurately sending a liquid material to a vaporizer at a small flow rate.

[0004]

The liquid material used in the liquid material vaporizer has a high corrosiveness and a low viscosity, such as THF (tetrahydrofuran). It is difficult to handle such as hydrolysis due to moisture in the air, and many materials are difficult to seal in the pump. That is, with an organic solvent such as THF used in the present apparatus, the liquid material that wets the surface of the plunger comes into contact with the atmosphere to produce a solid product by hydrolysis or volatilization, so that the plunger or the plunger seal sliding with the plunger Wear is promoted, and much higher abrasion resistance and corrosion resistance are required as compared with a general seal structure.

[0005] In view of such a situation, PTFE
Although (tetrafluoroethylene resin) is considered as one effective material in terms of corrosion resistance, PTFE itself cannot be used as a sliding member because it has a high coefficient of friction and a high coefficient of wear. Therefore, at present, powdered carbon is
Attempts have been made to mix it into a composite material and increase its hardness to use it as a sealing material. However, even if such a composite material is used, in a situation where the viscosity is low and lubrication by liquid is hardly expected, as in the sliding portion of the plunger pump, the carbon mixed with the PTFE is dropped from the PTFE base material due to the wear of the PTFE. Wear tends to occur, and the tendency to leak in a short period of time cannot be wiped out.

According to the present invention, the seal in the sliding portion of the liquid material feeding pump is made more appropriate, the wear of the sliding portion is suppressed as much as possible, and the service life is longer than that of the conventional one and the trouble of maintenance management can be eliminated. It is an object of the present invention to obtain a liquid material vaporizing device.

[0007]

In order to achieve the above object,
The present invention provides a plunger pump which supplies a vaporized liquid material to a vaporizer by quantitatively vaporizing the liquid material. The sealing material at a sliding portion of the plunger pump uses PTFE obtained by mixing carbon in a fiber shape. It is characterized by having been.

[0008] According to this structure, the carbon is mixed with the base material PTFE integrally in a state of being entangled with the base material. Therefore, the carbon is simply mixed into the PTFE even when used as a sealing material in the sliding portion. As compared with the case, carbon is not dropped in a short time. For this reason, it is possible to effectively suppress the progress of the wear of the seal material, and it is effective for a long time even when used as a seal material for a plunger pump that handles a liquid material in which wear and corrosion easily progress and solid products are easily generated. A good sealing function can be maintained.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. The liquid material vaporizer is equipped with a material container containing the liquid material, a plunger pump for liquid supply, and pipes connecting between them, as well as an external supply that enables vacuuming and purging inside the pipes and liquid supply from outside. Piping, valves, vaporizers, etc., which also serve as lines, are laid out. FIG. 1 shows an embodiment of the plunger pump 1 as a part directly related to the present invention.

In FIG. 1, a plunger 1 is provided with a piston motion by a drive source (not shown) disposed on the left side thereof, and reciprocates in the left-right direction in the figure while sliding with two plunger seals 2 and 3. I do. In this embodiment, ruby, sapphire, or the like is used for the plunger 1 in order to obtain high strength, high hardness, high corrosion resistance, and high abrasion. The tip of the plunger 1 is in the pump chamber 4. The pump chamber 4 is a hole formed in the pump head 5 and its internal volume changes in accordance with the reciprocating motion of the plunger 1. Therefore, the check valves 8 and 9 provided at the inlet 6 and the outlet 7 of the liquid material.
, The liquid flows in one direction (from the bottom to the top in this figure). That is, a pump action occurs.

The plunger 1 discharges the liquid when it moves rightward in the figure, and sucks when it moves leftward, and seals the sliding portions 1a and 1b of the plunger 1 on the liquid sending side. And the plunger seal 3 on the atmosphere side. Among them, the plunger seal 2 especially on the liquid sending side
In forming the first groove 51, as shown in detail in FIG. 2, a first concave groove 51 is formed around the inner periphery near the outer end surface of the pump head 5, and the position of the first concave groove 51 on the end surface side is determined by the position adjacent to the first concave groove 51. A second concave groove 52 having a deep bottom is formed. On the other hand, the seal member 20 is integrally connected to the seal lip 21 and the spring holding piece 22 inserted into the first groove 51 and the seal lip 21 and the spring holding piece 22 at the base end. The seal body 23 is provided at the distal end side and is inserted into the second groove 42. Then, the seal body 23 is inserted into the second groove 52, and the seal lip 21 and the spring holding piece 22 are inserted into the first groove 51 with the coil spring 24 interposed therebetween. doing.

The sealing material 20 of the plunger seal 2
Plays a role of sealing the liquid material in the pump chamber 4 while allowing the plunger 1 to move in the axial direction. The sealing material 20 is completely used for the purpose of lubricating the sealing material 20 and the plunger 1. The elastic force of the coil spring 24 is set so that the liquid material leaks little by little to the rear of the seal (left side in FIG. 1) so as to slightly wet the surface of the plunger 1 instead of stopping the liquid. Then, the seal lip 21 is appropriately pressed against the outer periphery of the plunger 1.

In this embodiment, as the material of the sealing material 20, a material obtained by mixing PTFE as a base material with carbon in a fiber shape (fibrous shape) is used. When the plunger pump having the above-described seal structure is operated in the liquid material vaporizer, the liquid near the plunger seal 1a flows between the plunger 1 and the seal lip 21 to obtain lubricity. Even if the liquid has a low viscosity as in this case, if the pressing force of the coil spring 24 is appropriately set and PTFE in which carbon is mixed into the material of the sealing material 20 is employed, the friction coefficient is significantly increased. Does not increase, and a part of the worn seal material does not separate from the seal body at the initial wear stage (in a state where the seal interference is left) as in the case of using PTFE itself, and the hydraulic pressure is maintained. Thus, the inconvenience of being caught between the plunger and the seal lip and causing leakage in a short period of time can be solved.

In addition to the above, the sealing material 2 used in this embodiment
No. 0 indicates that carbon is entangled with PTFE as a base material and is integrally mixed. Therefore, even if it is used for the sliding portion 1 a of the plunger 1, carbon is mixed in a short period of time, as in the case where carbon is simply mixed with PTFE. Will not fall off. For this reason, the progress of abrasion can be effectively suppressed, and it is effective for a long time as a sealing means of the plunger pump 1 as in the present embodiment, which handles a liquid material in which abrasion and corrosion easily progress and solid products are liable to occur. It is possible to maintain a good sealing function.

In this embodiment, the plunger 1 is located rearward.
The second plunger seal 3 is arranged in series at a distance greater than the reciprocation range of the cleaning liquid.
A closed chamber (cleaning chamber 10) is formed by covering with a housing 13 having a housing 2, and the cleaning chamber 10 is filled with a cleaning liquid, and a liquid material on a sliding surface of the plunger and products generated therefrom are washed off. The cleaning liquid is kept flowing at all times by another pump (not shown) provided outside, or is filled in a state where it can be periodically replaced. In this case, the same or the same kind of organic solvent used for the liquid material is used as the cleaning liquid.

Therefore, in the present embodiment, the surface of the plunger 1 can be constantly washed away to prevent a solid product from being generated, and even if a product is generated, it can be quickly dissolved and removed. Accordingly, the load on the plunger seal 2 can be reduced, and the sealing function can be more appropriately enhanced. The specific configuration of each part is not limited to those in the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the case where the present invention is applied to a single plunger type is described. In order to prevent interruption of liquid supply in a suction stroke, two plunger pumps having the same structure are arranged in parallel,
There is also a double plunger type driven by shifting the phase of the plunger by 180 degrees, and the present invention can naturally be applied to this double plunger type. Also,
In the above-described embodiment, a case was described in which the plunger seal was arranged twice in series with the plunger and the present invention was applied to the sealing material on the liquid sending side in order to prevent abrasion promotion by the product of the plunger seal. Of course, it is also possible to use it together with the sealing material on the side. Furthermore, such a 2
It goes without saying that the same function and effect can be obtained even if the present invention is applied to a pump that does not have a double seal structure and the liquid sending side is the atmosphere.

[0017]

As described in detail above, the present invention provides
The sliding part of the plunger pump used as the liquid flow rate control means in the liquid material vaporizer uses PTFE with carbon mixed in a fiber shape, so that while maintaining corrosion resistance, abrasion resistance etc. are enhanced and seal life is improved. In addition, the number of maintenance operations of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a plunger pump according to one embodiment of the present invention.

FIG. 2 is an enlarged view of the main part.

[Explanation of symbols]

 1: Plunger pump 20: Seal material

Claims (1)

[Claims] 1. A plunger pump comprising a plunger pump for quantitatively vaporizing a liquid material and supplying the vaporized liquid material to a vaporizer. A liquid material vaporizer, which is used.