JPH11159464A - Liquid material flow control pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply a semiconductor manufacturing CVD liquid material with high accuracy by filling an operating fluid into bellows to partition the inside of a casing, and constituting so as to suck in/deliver the liquid material by varying the volume of the bellows by sliding motion of a piston arranged in these bellows. SOLUTION: The inside of a casing 1 is partitioned into two chambers by bellows 2 having a large number of pleats, and an operating fluid 4 is sealed in an inside chamber of the bellows 2, and a piston 3 is fitted/installed. A suction side piping joint 6 enclosing a suction valve 8 communicating with an outside chamber of the bellows 2 in upper and lower parts and a delivery side piping joint 7 enclosing a delivery valve 9 actuated by a pressure difference of 1.0 to 100 kg/cm<2> , are installed in the casing 1. A liquid material 5 can be supplied in fixed quantity by delivering this by increasing pressure by sucking the liquid material 5 in the outside chamber of the bellows 2 according to the volumetric change by reducing/expanding a shape of the bellows 2 by reciprocatively slidingly moving the piston 3 in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid material flow control pump for supplying a liquid material for semiconductor production. More specifically, the present invention relates to a liquid material flow control pump for supplying a liquid material to a gas supply vaporizer of a chemical vapor deposition apparatus (CVD) or a physical vapor deposition apparatus (PVD).

[0002]

2. Description of the Related Art When a semiconductor device is manufactured, it is necessary to form a film such as a semiconductor film, an insulating film, and a metal film. As a main method of film formation, there are physical vapor deposition (PVD) using vacuum evaporation and sputtering, or chemical vapor deposition (CVD) using light or thermal energy. Of these, the CVD method (Chemical Vapo
rDeposition) is frequently used. In this method, a sample to be processed is treated with C such as an organic metal supplied from a gas supply device.
In this method, a CVD gas is decomposed by applying heat or light energy to a sample and placed in a VD gas atmosphere to form a semiconductor film, an insulating film, a metal film, and the like on the sample surface.

[0003] In recent years, the CVD raw materials used for the above-mentioned film formation have been increasing with the increasing integration, speeding up and diversification of semiconductor devices.
Due to the demand for more advanced film formation, organic tantalum compounds, organic barium compounds, organic titanium compounds, organic tungsten compounds, organic copper compounds, organic strontium, in addition to the conventional organic silicon compounds, organic aluminum compounds, etc. Use of a compound or an organic zirconium compound has been studied.

[0004] In the production of semiconductors, it is necessary to control the supply gas with high purity and accurate concentration and supply amount regardless of the type of CVD raw material. In addition, these liquid materials have high viscosity, are thermally unstable, and have a high chemical activity and are immediately degraded when exposed to moisture or oxygen in the air. It is necessary to vaporize and supply with high accuracy.

Conventionally, as a method of supplying a CVD liquid material to a CVD apparatus in gaseous form, a method of bubbling and supplying a carrier gas to a liquid material container and a method of supplying the liquid material to a vaporizer by a constant-rate pump and supplying the gas to the vaporizer are used. There is a method of vaporizing, or a method of keeping a liquid material in a pressurized state, supplying the liquid material to a vaporizer by a flow controller, and vaporizing the liquid material in a carrier gas. However, even among these, the method of supplying with a metering pump is capable of quantitatively supplying even when the vapor pressure, viscosity, heat capacity, etc. of the liquid material are different,
Generally, a metering pump is preferable, and a piston pump type is used.

[0006]

However, in the conventional piston pump, as the sliding portion of the piston moves into and out of the air through the gland packing portion, the liquid material slightly attached to the piston surface comes into contact with the air. There has been a problem that the material deteriorates and contaminates the piston sliding portion and the packing, which hinders operation. In addition, the external air components such as water and carbon dioxide gas entrained by the sliding of the piston degrade the quality of the liquid material, and further contaminate the discharge valve of the pump. there were. In addition, when the CVD apparatus is operated under reduced pressure, there is a disadvantage that the discharge side of the pump is reduced in pressure, so that the liquid material flows out. From the above, even if the operating condition of the CVD apparatus is normal pressure or reduced pressure,
It has been desired to develop a pump that can supply the liquid material with high precision and quantitatively without deteriorating the quality of the liquid material and that does not leak the liquid material or leak the gas.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have found that the present invention can solve the problem by constructing a pump by combining a liquid-sealed bellows and a piston. The present invention has been reached. That is, according to the present invention, a bellows is used to partition the inside of a casing into two chambers. A discharge-side pipe joint incorporating a discharge valve operating at a pressure difference of 0 to 100 kg / cm ² is welded, and an outer chamber of the bellows is connected to the suction-side pipe joint and the discharge-side pipe joint; A liquid material flow control pump characterized in that a liquid material is sucked and discharged through the bellows which expands and contracts by sliding the piston.

According to the present invention, the volume of the bellows is varied by sliding the hydraulic oil filling the bellows and the piston provided in the bellows, and the liquid material can be sucked and discharged. The pump is configured as described above. With this configuration, it is possible to supply the liquid material quantitatively with high accuracy in a state in which the liquid material is completely shut off from the outside air. It is made available. The present invention is applied to a pump for supplying a liquid material used in semiconductor manufacturing.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The bellows of the present invention is not particularly limited in shape as long as its volume can be easily changed in response to a small change in pressure and the shape can be easily restored. A multi-fold bellows is used. There is no particular limitation on the height of the folds relative to the diameter of the bellows in the cylindrical bellows, but if the folds are too small, it is unlikely that the volume will change.If the folds are too large, the space inside the bellows will be thin and the combination with the piston will be difficult. Due to restrictions, the height is usually 0.1 to 0.35 (fold height / bellows diameter),
Preferably it is about 0.15 to 2.5.

The ratio between the diameter and the length (length / diameter) of the cylindrical bellows is usually 0.15 to 10, preferably 0.1 to 10.
It is about 3 to 5. The thickness of the metal plate of the bellows varies depending on the material and the size of the bellows and cannot be specified unconditionally, but is usually 0.03 to 0.5 mm, preferably 0.08.
It is about 0.3 mm. The material of the bellows is not particularly limited as long as it does not cause corrosion and does not cause deterioration of the material due to repeated deformation.
16, SUS316L, tantalum or inconel is used.

The diameter and the sliding length of the piston for operating the bellows depend on the supply flow rate of the target liquid material and the variable range when the sliding length of the piston is changed to make the flow rate variable. Although designed and not particularly limited, the ratio of the maximum sliding length of the piston to the diameter of the piston (maximum sliding length / diameter) is usually about 0.2 to 10, preferably about 0.5 to 5.

The hydraulic oil sealed in the bellows is not required to be a liquid that maintains a liquid state in the operating temperature range and is not corrosive and has a particularly large viscosity. Are used.

If the maximum deformation rate of the bellows which is deformed in accordance with the sliding of the piston is too small, the volume efficiency is poor.
If it is too large, the bellows material will deteriorate due to repeated deformation.
~ 65%, preferably about 5-30%.

The suction valve and the discharge valve incorporated in the pipe joint are not particularly limited as long as they can seal the liquid material with high precision. It is composed of a combination with a seat or a combination of an elastic body such as a spring coil. Further, the discharge valve has an operating pressure difference of 1 to 100 kg / cm ² , preferably about ² to 30 kg / cm ^2, so that no outflow occurs due to suction even when the operation condition of the CVD apparatus is reduced. Is used.

A pipe joint for connecting a pipe to a pump is used by directly welding to a casing. The airtightness of the pipe joint is 1 × at the helium leak rate.
Those having 10 ^-9 Torr · L / sec or less are used.
Examples of these include a VCR joint (manufactured by Cajon Corporation, USA) and an MCG joint (manufactured by Toyoko Chemical Co., Ltd.). The suction valve and the discharge valve are provided in a welded pipe joint welded to the casing. With this configuration, it is possible to prevent leakage from the suction valve and discharge valve portions to the outside or contamination from the portions.

SUS316, SUS31, etc. are used as materials for contacting liquid materials such as pump casings, valves, fittings, etc.
6L, tantalum, inconel or the like is used. Of these, those polished electrolytically are particularly preferred. Further, in order to prevent a pulsating flow in the liquid supply, it is preferable to connect and use two or more pump units configured in this way in parallel. The number of slidings of the piston per pump unit is usually 1 to 1 because the pulse flow becomes large when too small and the quantification becomes bad when too large.
It is 30 times / second, preferably about 2 to 15 times / second.

The CVD liquid material supplied by the liquid material flow control pump of the present invention may be liquid at room temperature,
Even if the solid is dissolved in a solvent, it is not particularly limited as long as it can maintain a liquid state, and is appropriately selected and used according to the application. Examples of liquid material, trimethyl aluminum _{(Al (CH 3) 3)} , dimethylaluminum hydride _{(Al (CH 3) 2 H} ), triisobutylaluminum _{(Al (iC 4 H 9)} 3), tetraethoxysilane (Si (OC
₂ H _{5) 4),} hexacarbonyl molybdenum (Mo (CO) _6), dimethyl pentanedionate gold _{(Au (CH 3) 2 (} OC 5 H 7) 5), pentaethoxytantalum (Ta (OC ₂ H _{5) 5),} tetra-propylene oxytitanium _{(Ti (OC 3 H 7)} 4), tetrabutoxyzirconium
(Zr (OC ₄ H ₉ ) ₄ ), hexafluoroacetylacetone copper vinyltrimethylsilane ((CF ₃ CO) ₂ CHCu ・ CH ₂ CHSi (CH ₃ ) ₃ )
, Hexafluoroacetylacetone copper allyltrimethylsilane ((CF ₃ CO) ₂ CHCu · CH ₂ CHCH ₂ Si (CH ₃ ) ₃ ), bis (isopropylcyclopentadienyl) tungsten dihydride ((iC ₃ H ₇ C ₅ H ₅ ) ₂ WH ₂ ), tetrakisdimethylaminozirconium (Zr (N (CH ₃ ) ₂ ) ₄ ), and the like.

Further, bis (2,2,6,6, -tetramethyl-3,5
Heptandionite) barium (Ba (C ₁₁ H ₁₉ O ₂ ) ₂ ), bis (2,2,6,6, -tetramethyl-3,5 heptandionite) strontium (Sr (C ₁₁ H ₁₉ O ₂ ) ₂ ), tetra (2,2,6,6, -tetramethyl-3,5heptaneionite) titanium (Ti (C
_{11 H 19 O 2) 4)} , tetra (2,2,6,6, - tetramethyl-3,5 heptanedionite) zirconium _{(Zr (C 11 H 19 O} 2) 4), bis (2,2, 6,6, - tetramethyl-3,5 heptanedionite) lead _{(Pb (11 H 19 O 2} ) 2) , etc. are also used.

In addition to the compounds described above, solutions of these compounds in hexane, heptane, butyl acetate, isopropyl alcohol, tetrahydrofuran and the like can also be used.

Next, the present invention will be described in detail with reference to a partial sectional view of the casing of the pump shown in FIG. 1, but the present invention is not limited thereto. In FIG. 1, the inside of a casing 1 is divided into two chambers by a bellows 2 having many folds. A piston 3 is slidably inserted into the middle chamber of the bellows, and a working oil 4 is sealed in the space. A suction pipe joint 6 and a discharge pipe joint 7 are welded to upper and lower portions of the casing, respectively, and a suction valve 8 and a discharge valve 9 are incorporated therein. The discharge valve 9 is 1-100 kg / cm by a spring or the like.
It is set to operate with a pressure difference of about ² .

The bellows shrinks and expands in shape according to the sliding of the piston, and the liquid material 5 according to its volume change.
Can be supplied quantitatively by inhaling and discharging. Although FIG. 1 shows an example in which the piston slides in the bellows, the present invention includes a method in which the piston is provided at a position distant from the bellows and substantially the same effect is obtained by entering and exiting hydraulic oil.

By connecting a plurality of pump units configured in this way in parallel, the liquid material can be supplied with a small pulsating flow, with high accuracy, and without deterioration in quality. In addition, by controlling the pump by computer control, the pump can be automatically operated in accordance with the operation of the CVD apparatus.

[0023]

According to the present invention, a CVD liquid material for semiconductor production can be supplied with high accuracy and without deterioration in quality, regardless of whether the operating conditions of the CVD apparatus are normal pressure or reduced pressure.

[Brief description of the drawings]

FIG. 1 is a sectional view of a casing of a liquid material flow control pump according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casing 2 Bellows 3 Piston 4 Hydraulic oil 5 Liquid material 6 Suction side pipe joint 7 Discharge side pipe joint 8 Suction valve 9 Discharge valve 10 Hydraulic fluid sealing 11 Metal gasket 12 Packing

Claims (3)

[Claims] The interior of a casing is partitioned by a bellows into two chambers, and a bellows inner chamber is provided with a piston and hydraulic oil sealed with outside air and packing, and the casing has a suction-side pipe joint and a suction valve built-in. 0.0 to 100 kg / cm ²
The discharge side piping joint which incorporates the discharge valve which operates by the pressure difference is welded, and the outer chamber of the bellows is connected to the suction side piping joint and the discharge side piping joint. A liquid material flow control pump, wherein a liquid material is sucked and discharged through the bellows which expands and contracts. 2. The liquid material flow control pump according to claim 1, wherein the airtightness of the pipe joint is 1 × 10 ⁻⁹ Torr · L / sec or less in helium leak rate. 3. The material of the portion in contact with the liquid is SUS31.
6. The liquid material flow control pump according to claim 1, wherein the pump is SUS316L, tantalum, or Inconel.