JP2000249631A - Organic compound capturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly selectively sort and capture an organic compound in the air into a particulate substance and a gaseous substance by providing a particle capturing filter, an adsorption tube connected to a main tube of a rear stage from a connector of a branch tube and a gas adsorbent provided in the tube. SOLUTION: When the air to be sucked is sucked from an inlet of a main tube 1a, gaseous and particulate organic compounds are first moved in a tangential direction of the tube 1a in a macro manner. Since the tube 1a has a curvature at the inlet of a branch tube 2a, a flow of the air is disturbed. Particularly, since the particulate compound is arrived at the inlet of the tube 2a while holding motion in a tangential direction of the main tube due to its inertial force, the particulate compound can be captured by a filter 5 held at the inlet of the tube 2a. The gaseous compound lighter than the particulate compound by 8 places or more of its mass follows to a motion of a macro air flow in the tube 1a, carried to a main tube of a rear stage of a branch tube connector along a curvature of the tube 1a, and arrives at an adsorption tube 4a. Accordingly, the gaseous compound is adsorbed and captured by an adsorbent 6 provided at the tube 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for trapping organic compounds in ambient air, and more particularly, to separating and trapping particulate organic compounds and gaseous organic compounds in ambient air. It concerns the device.

[0002]

2. Description of the Related Art Semiconductor devices such as LSIs (Large Scale Integration) have been highly integrated and miniaturized. The number of manufacturing processes has increased to several hundreds, and the manufacturing process has taken a long period of several months. It has become to.

[0003] During the execution of such a large number of manufacturing steps,
Semi-finished semiconductor wafers are placed in a clean room to prevent contamination from outside air. However, LSI
Increasingly high integration and miniaturization have also caused a problem of contamination by organic compounds in an atmosphere of a clean room of an LSI. In particular, DRAM (Dynamic Random Access M
emory), when an organic compound in a clean room atmosphere adheres to a semiconductor wafer or enters a film forming apparatus, the withstand voltage characteristics of an insulating film forming a transistor deteriorate, For example, the threshold voltage of the transistor fluctuates, and the reliability and the yield are reduced. Therefore, in order to improve the reliability and the yield of the semiconductor device, it is required to periodically monitor the concentration of the organic compound in the clean room atmosphere to prevent the contamination of the semiconductor wafer.

As an apparatus for monitoring the degree of contamination in a clean room, there has been disclosed an apparatus which collects contaminants by intensively colliding air from a suction nozzle with a narrow area of a collecting plate (Japanese Patent Laid-Open No. 6-1994). 341679).

However, in order to elucidate the cause of the adverse effect of the organic compound in the air on the operation and reliability of the semiconductor device, it is necessary to determine whether the organic compound adheres to the semiconductor wafer in the form of particles or in the form of gas, that is, in the form of molecules. Should be considered separately. Therefore, when evaluating the type and concentration of organic compounds in the air, it is necessary to strictly separate and sample particles and gas (aerosol research vol.12 (2) 137) The importance of the problem (Fujii, Yuasa, key, Namiki, etc.). Also, in the evaluation of air and indoor pollution, the effect on the human body is different depending on the particles and the gas. Therefore, similarly, there is a need for the development of an apparatus for selectively separating and collecting the particles and the gas.

Conventionally, in order to analyze organic compounds in air with high sensitivity, the organic compounds are once trapped by some method. Then, after the trapped organic compound is extracted again with an appropriate organic solvent, quantitative analysis of the trace organic compound in the liquid is performed by a high-sensitivity analysis method, or after the trapping agent is heated and the organic compound is desorbed again, the gas is removed. In general, quantitative analysis is performed by a microanalytical method for organic compounds.

[0007] Further, as a method capable of almost completely collecting a boron compound existing in air as fine particles and molecular forms, a filter made of quartz fiber or the like and an adsorbent made of activated carbon or the like are used to pump air at a constant flow rate using a pump. A method has been used in which the air is passed through a trapping agent so that the trapping agent is adsorbed and collected.

[0008] As a device for separating and collecting a particulate organic compound and a gaseous organic compound, a filter made of fibers or the like is held in the first stage so as to first collect the particulate matter, and then collect the particulate matter. Separate collectors have been used that continuously hold an adsorbent made of activated carbon or the like and collect gaseous substances.

FIG. 4 shows J. High. Resol. Chromatgogr. Vol.
FIG. 20 (2) 99 is a schematic diagram of a conventional separation and collection device described in PAClausen et al. This sorting and collecting apparatus has a configuration in which a brass outer tube 21 in which adsorbents 6a and 6b are inserted in two stages is connected to a stage subsequent to the filter 5 held by holders 20a and 20b. This separation and collection device is sucked by the pump 22 from the latter stage, is aerated at a fixed flow rate for a fixed time, and collects an organic compound with a filter and an adsorbent. The collected organic compound is analyzed by a heated gas chromatograph-mass spectrometer, and is quantified using a previously prepared calibration curve.

As a specific configuration of the conventional apparatus, for example, a resin-based adsorbent filled in a glass tube having an inner diameter of 15 mmφ through a silicon tube into a 25 mmφ glass fiber filter held by a filter holder is used. Devices with connected structures are used (Environmental Chemistry vol.8 (1) 71
Pollution of indoor and atmospheric environment by vapor and particulate polycyclic aromatic hydrocarbons (Takahashi, Ameya, Matsushita).

As a specific configuration of the conventional apparatus, for example, an apparatus having a structure in which a 47 mmφ quartz fiber filter and an adsorbent having the same diameter are arranged in series is also used (Environmental Chemistry vol.8 (4)). 797 A method for collecting and analyzing polycyclic aromatic compounds using an adsorbent (Uraki, Suzuki).

[0012]

However, Japanese Patent Laid-Open No. 6-3 / 1994
A pollution degree monitoring device in a clean room described in Japanese Patent No. 41679 is a device that collects pollutants by intensively colliding outside air with a narrow region of a collection plate to increase a trapped concentration, and clean air is collected in the clean room. It is not possible to separate and collect the particulate organic compounds and gaseous organic compounds in them for monitoring.

[0013] Further, in the conventional separating and collecting apparatus, since the gaseous organic compound is also collected in the first-stage filter, not less than a small amount, it is possible to selectively and selectively collect the particulate matter and the gaseous substance. If not, the above-mentioned document, J.High.Resol.Chr
omatgogr. vol. 20 (2) 99, PAClausen et al.

The details that the conventional separation and trapping apparatus described in the above-mentioned document cannot separate and collect particulate matter and gaseous substances with high selectivity will be described in further detail. The separation and collection device described in the above-mentioned literature shown in FIG. 4 uses a 25 mmφ quartz fiber filter as a filter and an aromatic compound-based adsorbent TENAX-TA as an adsorbent. Flow rate 1500c
A total volume of 300 liters was aerated at 200 c / m for 200 minutes, and the organic matter captured by the filter and the organic matter adsorbed by the adsorbent were analyzed by a heated gas chromatograph-mass spectrometer, as shown in Table 1. Data is shown.

Table 1 shows that 2-butoxyethoxyethanol, dodecanoic acid, dibutyl phthalate (hereinafter abbreviated DB)
Even compounds containing a large amount of gaseous substances such as
This indicates that it is detected only from the filter. This is because even a gaseous substance having a relatively strong polarity is likely to be adsorbed to a filter.

[0016]

[Table 1] (The abbreviations of the substances in this table are BHT: butylhydroxytoluene, DEP: diethyl phthalate, DBP: dibutyl phthalate, DOP: dioctyl phthalate, and these abbreviations will be used hereinafter.)

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to an organic compound in air for selectively collecting organic compounds in air into particulate matter and gaseous matter. It is an object to provide a trapping device.

[0018]

A first apparatus for trapping organic compounds in air according to the present invention comprises a main pipe having a curved portion having a predetermined curvature, a main pipe connected to the curved section of the main pipe, and a connection direction of the main pipe. A branch pipe that is tangential to the curved part and has a closed outlet end, a particle trapping filter provided in the branch pipe, an adsorption pipe connected to a main pipe subsequent to a connection part of the branch pipe, With a gas adsorbent provided in the tube,
It has a means for separating and trapping organic compounds in the air into particulate matter and gaseous matter with high selectivity.

The second organic compound trapping device in the air according to the present invention is the same as the first organic compound trapping device, wherein the angle formed between the branch pipe and the main pipe at a stage subsequent to the junction of the branch pipe is 60. And a means for separating and collecting organic compounds in the air into particulate matter and gaseous matter with high selectivity.

[0020]

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

FIG. 1 is a schematic view of an apparatus for trapping organic compounds in air according to the present invention. The trapping device for an organic compound in air according to the present invention includes a branch pipe 2a having an outlet end sealed with a hermetic plug 3a in a tangential direction of a curved part of a main pipe 1a having a curved part with a predetermined curvature. A filter 5a is provided in the branch pipe 2a, and captures particulate matter of an organic compound. An adsorption pipe 4 is provided at the outlet of the main pipe 1b downstream of the connection of the branch pipe 2a.
Is provided. An adsorbent 6 is provided in the adsorption tube 4 and captures gaseous substances of organic compounds. Absorption tube 4
A suction device 7 such as a pump is provided at the subsequent stage, and the suction device 7
The target air is sucked from the inlet of the main pipe 1a by the action of (1).

With this configuration, when the target air is sucked from the inlet of the main pipe, first, the gaseous and particulate organic compounds move macroscopically in the tangential direction of the main pipe. Since the main pipe has a curvature at the entrance of the branch pipe, the flow of air is hindered. In particular, since the particulate organic compound reaches the inlet of the branch pipe while maintaining the tangential movement of the main pipe due to inertial force, the particulate organic compound is collected by the filter held at the inlet of the branch pipe. it can. On the other hand, the gaseous organic compound, which is lighter than the particulate organic compound by eight digits or more in mass, follows the motion of the macro air flow in the main pipe and is carried along the curvature of the main pipe to the main pipe at the subsequent stage of the branch pipe connection. Since the gas reaches the adsorption tube, the gaseous organic compound can be adsorbed and collected by the adsorbent provided in the adsorption tube.

The main pipe has a predetermined curvature at the inlet of the branch pipe, and by increasing the curvature, it is possible to increase the selectivity due to the difference in inertia between the particles and the gas. However, as long as the processing of the main pipe is possible, there is no limitation on its curvature.

FIG. 2 shows a main pipe having curved portions with a predetermined curvature at a plurality of locations, a branch pipe connected in a tangential direction to each curved portion of the main pipe, and having a closed outlet end, and a plurality of these branch pipes. A particle trapping filter provided in a pipe, an adsorption pipe connected to a main pipe at a stage subsequent to a connection portion of the branch pipe, and an air-based organic compound trapping apparatus including a gas adsorbent provided in the adsorption pipe FIG. In the air organic compound trapping device having the above structure in which a plurality of branch pipes provided with the particle trapping filter are provided, the trapping rate of the particulate organic compound is improved. In the apparatus for trapping organic compounds in air having the above structure, the direction in which the main pipe is bent is not particularly limited as long as processing is possible.

As the filter, a filter made of glass fiber, quartz fiber, or the like can be used, but there is no particular limitation as long as it can collect particulate organic compounds in the air.

As the adsorbent, an adsorbent of activated carbon type, aromatic compound type, silica type or the like can be used, but it is not particularly limited as long as it can collect gaseous organic compounds in the air. There is no.

The apparatus for collecting organic compounds in air according to the present invention may have a structure in which a plurality of devices are connected in parallel to a suction device such as a pump, in addition to the structure used alone. A device having a structure in which a plurality of the organic compound trapping devices in the air is connected in parallel to the suction device can increase the amount of organic compounds that can be collected and shorten the monitoring time.

Hereinafter, the present invention will be described with reference to examples. The present invention is not limited to these examples.

Embodiment 1 The air in the clean room was sucked into the main pipe using the apparatus having the configuration shown in FIG. In this apparatus, MODEL 2500QAT (manufactured by Tokyo Dylek Co., Ltd.) is filled in a branch pipe as a high-purity quartz fiber filter for trapping particulate organic compounds, and TENAX is used as an adsorbent for trapping gaseous organic compounds in the air. -TA (manufactured by GL Sciences) was provided in the adsorption tube. The adsorbent is preliminarily prepared in a clean airflow atmosphere that has passed through activated carbon.
It was used after heating at 50 ° C. for 3 hours to remove already adsorbed organic substances. The suction speed of air in the clean room depends on the TENAX-TA used as the adsorbent.
The recommended flow rate was 200 cc / m, and the suction time was 10 hours. The organic matter adsorbed on the adsorbent after the suction collection and the organic matter collected on the filter were quantitatively analyzed by a gas chromatograph-mass spectrometer. Table 2 shows the analysis results.

The object of measurement in this measurement was a so-called volatile organic substance having a boiling point in the range of 50 to 300 ° C. Filter traps are limited only to 26 minutes and beyond at the retention times shown in the chromatograms. In general, it can be said that a substance having a long retention time is likely to be present in the form of particles, so that the filter trapping substance does not contain a gaseous substance. In particular, in the air, DOP which is mostly present in the form of particles is collected only by the filter.

On the other hand, the retention time of the adsorbent-collecting substance is in the range of 9 minutes to 36 minutes shown in the chromatogram.
The substance collected at a high concentration by the adsorbent is a substance whose retention time is within 23 minutes, and is hardly collected by the filter. Also, DBP (Atmospheric Environment Society, 1998 Autumn Preliminary Proceedings, P422, Masahiro Hori), which is said to contain only about 10% as particles, has about 5%
But only most are trapped by the adsorbent. As is clear from these results, the present trapping device is a device capable of efficiently separating an organic compound into a particulate matter and a gaseous substance.

[0032]

[Table 2] (Abbreviations of the substances in this table are D5: 5-membered cyclic siloxane, D8: 8-membered cyclic siloxane.)

Embodiment 2 FIG. FIG. 3 shows an embodiment of the organic compound collecting apparatus of the present invention, which is connected to a generator 10 for generating standard substances of a particulate organic compound and a gaseous organic compound.
DOP, which is mostly in the form of particles, was used as the standard substance 11 of the particulate organic compound, and DBP, in which 10% was in the form of particles and mostly in the form of gas, was used as the standard substance 12 of the gaseous organic compound. Each standard substance was left at room temperature in a sealed petri dish of the generator, air in a clean room was passed through the room of the standard substance generator, and this air was forcibly contaminated with each standard substance. This contaminated air was passed through the collection device of the present invention. The used filters, adsorbents, suction conditions and the method of analyzing the collected substances are the same as in Example 1.

Table 3 shows the results. The fractional collection ratio of DOP (adsorbent concentration / filter concentration) is very small, indicating that most of the particulate DOP is trapped by the filter. Conversely, the fractional collection ratio of DBP (the concentration of the adsorbent trap / the concentration of the filter trap) is large, indicating that most of the gaseous DBP is trapped by the adsorbent. That is, the collection device of the present invention is a device capable of separating and collecting the particulate organic compound and the gaseous organic compound in the clean room with high efficiency.

[0035]

[Table 3] Fractionated collection ratio = adsorbent trapped concentration / filter trapped concentration

Embodiment 3 FIG. The angle θ between the branch pipe 2a and the main pipe 1b downstream of the connection between the branch pipe 2a and the branch pipe 2a is 45 degrees, 60 degrees,
The air in the clean room was collected and analyzed in the same manner as in Example 2 using each of the organic compound collection devices at 75 degrees, 90 degrees, 115 degrees, and 135 degrees. Table 4 shows the results. In all the apparatuses used in this example, the fractional collection ratio of DOP is small, the fractional collection ratio of DBP is large, and it is shown that the particulate organic compound and the gaseous organic compound can be fractionally collected. In particular, the angle θ between the branch pipe and the main pipe downstream of the connection between the branch pipes is 60 degrees, 75 degrees, 90 degrees, 115 degrees,
In each of the organic compound collecting devices at 135 degrees, the fractional collection ratio of DOP is particularly small, indicating that the collection rate of the particulate organic compound in the filter is high. That is, in the trapping device of the present invention, in order to separate and collect the particulate organic compound and the gaseous organic compound in the clean room with high efficiency, the angle θ formed between the branch pipe and the main pipe at a stage subsequent to the branch pipe connection part is preferred.
Is preferably 60 degrees or more.

[0037]

[Table 4] Fractionated collection ratio = adsorbent trapped concentration / filter trapped concentration

As an embodiment, air sampling in a clean room for manufacturing a semiconductor manufacturing apparatus has been described. However, the present invention can also be used for evaluating other air impurities in a general room or the like. It is not limited.

[0039]

According to the first apparatus for trapping organic compounds in air according to the present invention, a main pipe having a curved portion having a predetermined curvature is connected to the curved portion of the main pipe, and the connection direction is a tangent to the curved portion of the main pipe. A branch pipe having a closed outlet end, a particle trapping filter provided in the branch pipe, an adsorption pipe connected to a main pipe subsequent to a connection part of the branch pipe, and a suction pipe provided in the adsorption pipe. Gas adsorbent, and has the effect of having means for separating and collecting organic compounds in air into particulate matter and gaseous substances with high selectivity.

The second organic compound trapping device in the air according to the present invention is the same as the first organic compound trapping device, wherein the angle formed between the branch pipe and the main pipe downstream of the junction of the branch pipe is 60 degrees. Degree or more, and has the effect of having means for separating and collecting organic compounds in the air into particulate matter and gaseous matter with high selectivity.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for separating and collecting organic compounds in air according to Embodiment 1 of the present invention.

FIG. 2 is a schematic view of an apparatus for separating and collecting organic compounds in air provided with a plurality of branch pipes provided with a filter for collecting particulate matter according to the present invention.

FIG. 3 is a schematic view of an apparatus for separating and collecting organic compounds in air according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of an apparatus for separating and collecting organic compounds in air showing a conventional example.

[Explanation of symbols]

1a-1f Main pipe, 2a-2e Branch pipe, 3a-3
e Seal stopper, 4 Adsorption tube, 5-5e filter, 6
~ 6b adsorbent, 7 suction device, 10 reference material generator, 11 reference material of particulate organic compound, 12
Gaseous organic compound reference material, 13 heater, 20
a, 20b filter holder, 21 outer tube, 22 pump

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D012 CA10 CA11 CB01 CG01 CH10 CK10 4D031 AB03 BA03 BA06 BA10 DA05 EA01

Claims (2)

[Claims] 1. A main pipe having a curved part with a predetermined curvature, a branch pipe connected to the curved part of the main pipe, the connection direction being tangential to the curved part of the main pipe, and an outlet end sealed. And a gas adsorbent provided in the adsorption pipe connected to the main pipe at a stage subsequent to the junction of the branch pipe, and a gas adsorbent provided in the adsorption pipe. apparatus. 2. The organic compound collecting apparatus according to claim 1, wherein an angle formed between the branch pipe and a main pipe at a stage subsequent to a connection part of the branch pipe is 60 degrees or more.