JP3061471B2 - Liquid sampling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid sampling apparatus used for analyzing a liquefied purified gas for a semiconductor process, for example.

[0002]

2. Description of the Related Art For example, in a semiconductor processing apparatus, a gas (for example, nitrogen gas) used in the processing apparatus is produced by an air separation device, the gas is filled in a tank lorry, and the tank lorry is transported to the use site. What is going on.

[0003] In this case, it is necessary to accurately analyze the components of the gas extracted from the tank lorry before or during operation of the process apparatus. As such an analyzer, an APIMS (atmospheric pressure) is typically used. Ionization mass spectrometer). However, this A
Since the PIMS is a large-scale device, if the installation location of the process equipment is remote from the manufacturing location, the PIMS is brought to the installation location regardless of a considerable margin in the installation cost and the installation area. That is generally too great a financial or human burden.

[0004] Therefore, conventionally, at the installation site of the apparatus, a part or all of the extracted liquefied gas is filled in a liquid sampling container, and the container is removed from the installation site by A.
A technique is employed in which the liquefied gas is transported to a permanent location of the PIMS for component analysis.

In this case, the liquid sampling vessel communicates with the inner tank made of stainless steel, the outer tank made of carbon steel provided outside the inner tank with a decompression space interposed therebetween, and the inner tank. A liquid pipe provided as described above, a gas supply pipe communicating with the inside of the inner tank, a liquid inlet / outlet valve part provided with the bellows valve provided in the liquid pipe, a gas blow valve part provided in the gas supply pipe, An external heating unit for externally heating the blow gas flowing through the gas supply pipe, the inner surface of the inner tank is generally finished to a rough surface of about several tens of microns, and the piping system is made of copper or the like. Is used.

[0006]

However, in the structure of the above-mentioned conventional liquid sampling container, sufficient measures have not been taken against generation of harmful impurities, external leakage, etc., particularly in the semiconductor manufacturing process. It could not respond to analysis, that is, so-called ppt level trace analysis.

First, at the time of baking the container, the blow gas heated only by the external heating unit is merely fed into the container, so that the temperature in the container cannot be sufficiently increased. Second, the inner tank of the container
Since the inner surface of the inner surface is merely a surface having a roughness of several tens of microns at most, impurities such as water and carbon dioxide from the inner wall surface were easily desorbed under reduced pressure. Third, since the valve portion is constituted by a bellows valve made of a bellows made of gunmetal, a gland packing, and the like, it has been difficult to suppress emission of harmful particles and hydrocarbons.

Therefore, in the conventional method, 10 to 20 p
Although analysis at the pb level can be performed, trace analysis with ultra-high accuracy at the ppt level cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a liquid sampling apparatus capable of performing liquid sampling with extremely high precision and component analysis thereof.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the main object of the present invention is to provide a stainless steel inner tank having a mirror-finished inner surface and a depressurized space outside the inner tank. A metal outer tank provided by being provided, a liquid pipe having a tip side inserted into the inner tank, an internal heating unit provided in the inner tank, and the liquid pipe protruding outside the inner tank. A first metal valve provided, a gas supply pipe communicating with the inner tank and provided with a second valve, and provided outside the gas supply pipe and detachable from the second valve. And an external heating unit.

In this case, when the inner surface of the inner tank is mirror-finished by, for example, electrolytic polishing (including electrolytic composite polishing),
It is suitable for suppressing the release of impurities at low temperatures. Furthermore, there is an advantage that baking in the inner tank can be performed in a short time.

By performing a heat treatment (for example, heating at 300 to 420 ° C.) in an inert gas atmosphere containing an inert gas such as Ar or an oxygen gas, an amorphous surface is formed on the mirror-finished inner surface. It is preferable to form an oxidation passivation film in advance. In this case, outgassing from the inner surface of the inner tank can be significantly reduced, and not only can baking in the inner tank be performed in a short time, but also contamination of the sampling liquid with impurities can be significantly reduced. Therefore, the analysis of the sampling liquid can be performed with high accuracy.

Further, it is preferable that the gas contact portion in the valve portion, the gas supply pipe and other portions is also mirror-finished by, for example, electrolytic polishing, and the amorphous passivation film is coated on the mirror-finished surface. It is more preferable to form them.

[0014]

According to the above means, the blow gas (for example, nitrogen gas) which has passed through the external heating unit is supplied into the inner tank through the second valve unit, and the temperature in the inner tank is directly controlled by the internal heating unit. After baking the container by raising to
Fill a container with a purified gas (eg, purified nitrogen gas),
A liquid for sampling (for example, liquid nitrogen) is filled in the inner tank via the first valve portion. When the liquid is liquid nitrogen, filling is performed while discharging nitrogen gas in the inner tank from the third valve portion. In this case, since each valve portion is made of metal and the inner surface of the inner tank is mirror-finished by, for example, electrolytic composite polishing, it is possible to suppress the release of impurities from the inner surface of the inner tank.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an example of a liquid sampling apparatus according to the present invention. A vertically long cylindrical container 1 is roughly composed of an inner tank 2 and an outer tank 3. A high-vacuum space 4 is formed therebetween. The inner tank 2 is
For example, it is made of SUS316L, and its inner surface is finished to have a mirror surface having irregularities of about 0.1 μm by electrolytic combined polishing.

A lid 5 is provided on the upper portion of the inner tank 2, and a rod-shaped internal heater 6 inserted into the inner tank is attached to the center of the lid 5. Further, a liquid pipe 7 is provided in the inner tank 2 substantially parallel to the heater 6, and an upper end side of the liquid pipe 7 penetrates through the lid 5 and protrudes to the outside. A liquid inlet / outlet valve 8 as a first valve portion is provided in the protruding pipe portion, and a gas release valve 9 as a third valve portion is provided on the side opposite to the lid of the valve 8.

Further, a gas supply pipe 10 is attached to the lid 5, and the lower end of the gas supply pipe 10 is connected to the inner tank 2.
And a gas blow valve 11 as a second valve portion is provided on the upper end side. The gas supply pipe 10 is provided with a first branch pipe 12.
, A pressure gauge 13, a safety main valve 14, and a safety valve 15 are provided in that order. Further, the first branch pipe 12 is connected to a booster pipe 19 via a booster control valve 16, a booster source valve 17, and a gas release valve 18, and the end of the booster pipe 19 is connected via a vaporizer. It faces the bottom of the inner tank 2. A second branch pipe 20 is connected to the gas supply pipe 10, and the second branch pipe 20 is provided with a pressure reduction source valve 21 and a pressure reduction adjustment valve 22.

The outer tub 3 is made of, for example, SUS304, and a coating portion 3a for name is formed on the outer surface thereof, and buffing portions 3a are formed on both upper and lower sides of the coating portion 3a.
b is formed (see FIG. 3). An outer tank safety valve 23 is provided on the upper part of the outer tank 3.

The gas supply line 24 connected to the gas blow valve 11 is provided with an external heater 25 for heating from outside the pipe.

Here, all parts such as a valve seat and a diaphragm constituting the first to third valve portions and the like are made of metal or have at least a metal diaphragm.
All the liquid contact parts and gas contact parts of the piping system such as the second branch pipe are finished by electrolytic polishing.

Next, an example of use of the present embodiment configured as described above will be described.

For example, in the case of sampling a liquefied gas (for example, liquefied nitrogen) used in a semiconductor processing apparatus, first, the external heater 25 of the gas supply line 24 is operated and the internal heater 6 is operated (both are energized). ) And blow gas (nitrogen gas) heated to a predetermined temperature
Is supplied into the inner tank 2 through the gas supply pipe 10 and the container 1
Baking. After the baking is completed, the current to the external heater 25 and the internal heater 6 is cut off, cooled to room temperature with a blow gas (nitrogen gas), and
The hermeticity is maintained at a pressure of less than kg / cm ^{2, and} the connection of the external heater 25 is disconnected for convenience of subsequent transportation and the like.

First, the valve 11 is opened to release gas in the inner tank, and the liquid inlet / outlet valve 8 is opened to guide liquefied nitrogen extracted from a tank lorry or the like to the liquid pipe 7, and the gas blow valve 11 opens the inner tank 2. The inner tank 2 is filled with liquefied nitrogen while maintaining the pressure. When a predetermined amount of liquefied nitrogen is charged, the gas blow valve 11 is closed, and then the liquid inlet / outlet valve 8 is closed.

When the filling of the sampling liquid is completed, the container 1 is transported to a place where the APIMS is installed by a predetermined transport means. In order to analyze the sampled liquid after the transfer, an APIMS is connected to the liquid inlet / outlet valve 8 and the pressurization source valve 17 is opened,
The opening degree of the pressure-up regulating valve 16 is appropriately set, and the upper pressure of the inner tank 2 is increased by vaporized liquefied nitrogen guided to the upper part of the inner tank 2 via the pressure rising pipe 19, and the liquefied nitrogen in the inner tank 2 is liquefied. The liquid is guided to the outside of the inner tank 2 through the pipe 7 and the liquid inlet / outlet valve 8 to perform a predetermined measurement.

[0026]

As described above, according to the first aspect of the present invention,
A stainless steel inner tank having an inner surface mirror-finished, a metal outer tank provided outside the inner tank with a depressurized space interposed therebetween, and a liquid having a distal end inserted into the inner tank. A pipe, an internal heating unit provided in the inner tank, and a first metal pipe provided on the liquid pipe protruding outside the inner tank.
A gas supply pipe provided in communication with the inner tank and provided with a second valve section, and an external heating section provided outside the gas supply pipe and detachable from the second valve section. With the configuration, by providing an internal heater, it is possible to perform more sufficient dehydration than before, and furthermore, since the inner surface of the inner tank is mirror-finished, the release of unnecessary impurities can be suppressed,
High-precision analysis of a sampling liquid can be easily performed, and it is particularly useful when the sampling site is remote from the analysis site.

According to the second aspect of the present invention, the release of impurities from the inner surface of the inner tank can be more sufficiently suppressed by the electrolytic combined polishing.

According to the third aspect of the present invention, the amorphous passivation film is formed on the mirror-finished surface by heat treatment in an inert gas (or an inert gas containing oxygen) atmosphere. It is significantly reduced, and the sampling liquid can be measured with high accuracy.

According to the fourth aspect of the present invention, by providing the third valve portion near the second valve portion, it is possible to easily maintain a low temperature in the inner tank at the time of filling the liquefied gas or the like. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a top view of the container according to the present embodiment.

FIG. 3 is a front view of the container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Container 2 ... Inner tank 3 ... Outer tank 6 ... Internal heater 8 ... Liquid inlet / outlet valve (1st valve part) 9 ... Gas release valve (3rd valve part) 11 ... Gas blow valve (2nd valve part) 25) External heater

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G01N 1/00 101 F17C 1/12 G01N 1/10

Claims (4)

(57) [Claims] 1. A stainless steel inner tank whose inner surface is mirror-finished, a metal outer tank provided outside the inner tank with a space capable of being depressurized, and the inner tank having a tip end side. A liquid pipe inserted therein, an internal heating section provided in the inner tank, a metal first valve section provided in the liquid pipe protruding outside the inner tank, and A liquid sampling apparatus comprising: a gas supply pipe provided with a communicating second valve section; and an external heating section provided outside the gas supply pipe and detachable from the second valve section. apparatus. 2. The liquid sampling apparatus according to claim 1, wherein the mirror finishing is performed by electropolishing. 3. An amorphous oxide passivation film formed by heat treatment in an inert gas atmosphere containing an inert gas or oxygen after electrolytic polishing is formed on the mirror-finished surface of the inner tank. 3. The liquid sampling device according to claim 2, wherein 4. The liquid pipe according to claim 1, wherein a third valve section made of metal is provided so as to communicate with the inner tank. Liquid sampling equipment.