JP2004226336A - Method and sampling instrument for measuring vaporized organic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately sample an organic compound generated from a surface of a solid such as a clean room building member. <P>SOLUTION: A vaporization chamber is formed on a tip opening side of a container for constituting a sampling instrument for measuring the organic material vaporized from the surface of the solid. A sleeve for approaching a suction opening to the vaporization chamber and having a detachable adsorption pipe is provided within a sampling container. A carrier gas supply path provided with an adsorbing agent for capturing the organic material from a carrier gas introduced into the vaporization chamber is formed around the sleeve. The vaporized organic material is measured by bringing the opening of the vaporization chamber of the sampling container into contact with the surface of the solid and sealing and introducing the carrier gas. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for measuring volatile organic substances and a sampling instrument for measurement, and more particularly to a method and a sampling instrument for measuring volatile organic substances suitable for measuring organic substances volatilized from the surface of a construction material of a clean room constituting a semiconductor manufacturing facility.
[0002]
[Prior art]
Generally, semiconductor manufacturing is performed in a clean room, and in particular, it is necessary to prevent impurities from adsorbing to semiconductor wafers during the manufacturing process. In particular, when an organic compound existing in a clean room atmosphere is adsorbed on the surface of a semiconductor wafer, there is a problem that the electrical characteristics of an integrated circuit formed on the wafer are affected.
[0003]
Organic compounds originate from a variety of organic materials, but can be problematic from plastic materials used to build the clean room itself, and from uncut material surfaces, and therefore volatilize from the solid surfaces of these clean room building components. It is necessary to evaluate the organic compounds that are adsorbed on the wafer surface. A typical example of the organic compound to be adsorbed is dioctyl phthalic acid (DOP). DOP is frequently used as a plastic additive in plastic materials. DOP has a boiling point of 360 ° C. and slightly evaporates at room temperature. Usually, a trace amount of 0.1 to 1 ng / L is contained in a clean room atmosphere.
[0004]
There has been proposed a method for accurately measuring a plastic material constituting a conventional existing clean room and a highly adsorptive organic compound volatilized in a trace amount from the surface of a material that cannot be cut. For example, the on-site measurement method described in Non-Patent Document 1 is used. FIG. 10 shows a schematic diagram of a system for implementing this measuring method. The chamber 2 is put on the surface of the evaluation target member 1 which is a clean room construction material, a carrier gas is introduced into the test chamber 2, and the organic compound volatilized in the test chamber 2 is discharged out of the test chamber along with the carrier gas. The organic matter is collected by the collection pipe 3 connected to the piping of the exhaust path. It is described that the material of the pipe, the test chamber 2 (the size is about 20 cm in width and height) of such an evaluation device, and the material of the connection part are stainless steel or glass. Before the carrier gas is introduced into the chamber 2, the carrier gas is subjected to a cleaning process by an impurity removing unit 4 composed of a filter or the like. Thereafter, the collection tube is removed, and then attached to a thermal desorption type gas chromatograph, and organic substances are measured.
[0005]
There are various types of chambers 2, for example, a rectangular container chamber 2A as shown in FIG. In this method, a carrier gas inlet 5 is provided on the side surface, a carrier gas accompanied by volatile organic substances is discharged from an outlet 6 provided on the top end face, and the organic gas is collected by passing the gas through a collection pipe. I have. As shown in FIG. 12, the chamber 2B has a double-chamber bell shape. A carrier gas is supplied and introduced into the inside from below through a passage between both chambers. Then, the carrier gas accompanied by the volatile organic substance is discharged from the upper end of the inner chamber, and the organic substance is collected by a collection pipe connected to the piping of the exhaust path.
[0006]
[Non-patent document 1]
"Guidelines for measuring method of molecular pollutants generated from materials used in clean rooms (draft)" (Japan Air Cleaning Association)
[0007]
[Problems to be solved by the invention]
However, the problem with the above-mentioned conventional measurement method is that among the organic compounds generated from the solid surface, those having a strong adsorptivity are adsorbed on the inner surface of the measurement container or the pipe and cannot reach the collection pipe, and the generated organic compound is not absorbed. This means that the type and amount of the compound cannot be measured accurately.
[0008]
An object of the present invention is to reduce the influence of an organic compound generated from a solid surface such as a clean room building member, particularly an organic compound that strongly adsorbs on a semiconductor wafer surface and affects electric characteristics in a sampling container and a pipe inner surface at the time of sampling. It is an object of the present invention to provide a volatile organic substance measuring method and a measuring sampling instrument that can improve the measuring accuracy at a reduced level.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method for measuring volatile organic matter according to the present invention is a method for measuring organic matter volatilized from a solid surface, wherein an opening of a volatilization chamber formed in a sampling vessel is applied to the solid surface. The carrier gas is subjected to self-cleaning treatment by trapping and removing organic matter through the adsorbent into the volatilization chamber, and the carrier gas is passed through an adsorption tube having a suction port facing the volatilization chamber. The method is characterized in that organic substances entrained in the carrier gas are adsorbed by the adsorption tube by flowing, and the volatile organic substances captured by the adsorption tube are measured. At this time, the adsorbent of the carrier gas, the sampling container, and the adsorption tube may be preliminarily cleaned by heating to perform sampling.
[0010]
The sampling instrument for measuring volatile organic matter according to the present invention is a sampling instrument for measuring organic matter volatilized from a solid surface, wherein a volatilization chamber is formed on the tip opening side of the sampling vessel and the volatilization chamber is provided inside the sampling vessel. Forming an adsorption tube mounting portion in which the suction tube is detachably mounted with the suction port facing the chamber, and a carrier gas supply path including an adsorbent for capturing organic substances from the carrier gas introduced into the volatilization chamber, The volatile organic matter can be measured by introducing the carrier gas by sealing the opening of the volatilization chamber of the sampling container against the solid surface and introducing the carrier gas.
[0011]
That is, in the present invention, it is very difficult to collect all the organic compounds having a strong adsorptivity in the adsorption tube, so the chamber for volatilization is reduced in size, and the chamber can be heated and cleaned. It was obtained based on the knowledge that it is sufficient to eliminate the connection of cylinder gas, gas piping, and clean columns as a structure that reduces adsorption and a structure that can self-clean volatilizing gas, and reduce the complexity of the structure to a structure that reduces interference. . As the adsorbent of the adsorption tube for measuring volatile organic substances, a tenax adsorbent capable of capturing all organic substances and a silicon powder adsorbent capable of selectively adsorbing only organic compounds adsorbed on the silicon surface may be used. Alternatively, a structure may be employed in which an organic compound adsorbed on silicon and a non-adsorbable organic compound are simultaneously measured by joining a silicon powder adsorbent and a tenax adsorbent in series. After volatilization sampling from the solid surface, the adsorption tube is measured by a thermal desorption type gas chromatograph. This allows accurate measurement including an organic compound having strong adsorptivity.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of a method for measuring volatile organic matter and a sampling instrument for measurement according to the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 shows a volatile organic matter measurement sampling instrument 10 according to the embodiment. The sampling device 10 is configured so that the suction tube 12 shown in FIG. 2 can be detachably mounted. The adsorption tube 12 shown in FIG. 2 captures a volatile organic compound, and is configured to be directly mounted on a gas chromatograph. That is, a suction port 16 is formed by tapering a tip portion of one end of a cylindrical quartz tube 14, and a plug 18 made of a fluororesin material is attached to an opening portion of the other end. An adsorbent 20 is loaded in the quartz tube 14, and a quartz glass filter 22 is provided to partition the quartz tube 14 from the suction port 16, and a tenax agent capable of trapping all organic substances as the adsorbent 20 therein. Activated carbon, a zeolite agent, or a plurality of adsorbents are packed in tandem. When used as an adsorbent 20 for capturing organic substances that are selectively adsorbed on the silicon surface, silicon powder is used. When measuring an organic compound adsorbed on a solid surface other than silicon, it can be trapped by forming an adsorption tube with the material and using a powder of the material as an adsorbent. The adsorbent 20 housed inside the quartz tube 14 has a fixed quartz wool 24 held at a fixed position inside.
[0014]
FIG. 3 is a cross-sectional view of the sampling device 10, which is provided with a mounting sleeve 28 that allows the suction tube 12 to be mounted and detachable inside an outer sampling container 26 made of cylindrical quartz. , As a double tube structure. A volatilizing chamber 30 is formed at the lower end opening of the sampling vessel 26, and is separated by a quartz glass filter 32, and the tip of the adsorption tube mounting sleeve 28 is opened at the center. An annular space formed between the sampling container 26 and the mounting sleeve 28 is a carrier gas supply passage 34, which is filled with an adsorbent 36 for purifying the carrier gas, and whose upper surface is fixed and held by quartz wool 38. Like that. Thus, when the carrier gas is supplied to the air supply passage 34, the carrier gas is introduced into the volatilization chamber 30 in a clean state in which the organic compound in the gas is captured when passing through the adsorbent 36. The sampling vessel 10 is used by sealing the volatilization chamber 30 by joining the opening at the tip of the volatilization chamber 30 to the solid surface to be measured.
[0015]
At the time of actual measurement, as shown in FIG. 1, the sampling unit is configured by inserting and inserting the adsorption tube 12 into the center of the sampling container 10. The assembled sampling unit is installed on the solid surface 40 to be measured. The opening of the volatilization chamber 30 is pressed against the solid surface 40 in the clean room to be measured. The suction passage 18a formed in a certain fluorine resin stopper 18 is connected to a suction pump (not shown) or the like. As a result, the inside of the adsorption tube 12 becomes a negative pressure, and clean room air (carrier gas) is introduced from the inlet 42 formed around the fluororesin plug 18 above the sampling container 26. The clean room air is cleaned by passing through the adsorbent 36, and a clean gas is discharged into the volatilization chamber 30 from the entire surface of the lower quartz glass filter 32. In the volatilization chamber 30, the carrier gas flows toward the suction port 16 of the adsorption tube 12 arranged at the center, so that the organic compounds volatilized from the solid surface 40 are guided to the clean air flowing toward the center thereof, and the sampling is performed. Instead of being adsorbed on the inner wall of the container 26, it is adsorbed in the adsorption tube 12 facing the suction port at a position approximately 1 cm from the fixed surface. After sampling for a certain period of time, the adsorption tube 12 is removed from the sampling unit, put into a storage / transport tube shown in FIG. 6 described later, and measured by a thermal desorption type gas chromatograph mass spectrometer.
[0016]
When such a sampling device 10 and the adsorption tube 12 are used for measurement, a cleaning process is performed before the measurement. The method of cleaning the adsorption tube 12 and the sampling device 10 may be performed as follows. FIG. 4 shows a schematic diagram of a method for cleaning the adsorption tube 12. While the adsorption tube 12 is heated by a heating means 44 such as a heating furnace or a ribbon heater, an inert gas (helium, nitrogen gas) is caused to flow therein to clean the adsorbent 12. Further, as shown in FIG. 5, even when the cleaning method of the sampling device 10 is performed, the gas can flow only through the carrier gas supply passage 34 in which the adsorbent 36 in the sampling container 26 is loaded and the volatilization chamber 30. Plugs 46 and 48 made of fluororesin (made of PTFE) are attached to the upper and lower openings of the container 26. Next, an inert gas (helium, nitrogen gas) is flowed while heating with a heating means 50 such as a heating furnace or a ribbon heater to clean the adsorbent.
[0017]
Next, the storage and transport of the adsorption tube 12 and the sampling device 10 are performed as follows. The adsorptive organic compounds in the atmosphere are strongly adsorbed and are stored after being subjected to a cleaning treatment, and are sealed with a fluororesin stopper to be transported to a sampling location. That is, FIGS. 6 and 7 show schematic diagrams of storage and transport of the adsorption tube 12 and the sampling device 10. FIG. The suction tube 12 is stored and transported in a sealed container 51 covered with a fluororesin stopper. Further, the sampling device 10 may be stored and transported by covering the upper and lower openings of the container 26 with the sealing stopper 52.
[0018]
In the solid surface volatile organic compound sampling instrument 10 shown in FIG. 3, an error may occur if the volatilized organic compound adheres to the inner wall surface of the evaporation chamber 30 of the sampling container 26. Therefore, if the entire inner wall of the volatilization chamber 30 is formed by a quartz filter and a purifying carrier gas is introduced, it can be used for sampling for measuring a trace amount of volatile organic compounds. For example, when the quartz air filter 32 below the sampling device 10 is used as a conical filter 32A (FIG. 8) or a pot-shaped filter 32B (FIG. 9), a clean air stream is discharged from the entire surface of the quartz filter unit, and thus volatile organic compounds are emitted. Errors due to the attachment of the compound to the sampling device can be reduced.
[0019]
【The invention's effect】
According to the present invention, it is possible to accurately evaluate a trace amount of an organic compound having a particularly high adsorptivity, which volatilizes from a solid surface. This makes it possible to accurately evaluate the organic compounds that evaporate from the existing clean room constituent materials (floor, paint, walls, etc.). Eventually, it is possible to contribute to the improvement of the reliability and yield of semiconductor devices and liquid crystals whose product characteristics are affected by the adsorbed organic compound.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a sampling device equipped with an adsorption tube according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an adsorption tube for trapping volatile organic compounds.
FIG. 3 is a cross-sectional view of a solid surface volatile organic compound sampling instrument with a volatilizing gas self-cleaning function.
FIG. 4 is a cross-sectional view showing a method of cleaning the adsorption tube for trapping volatile organic compounds.
FIG. 5 is a cross-sectional view showing a dispute law of a solid surface volatile organic compound sampling device with a volatilizing gas self-cleaning function.
FIG. 6 is a cross-sectional view showing a storage / transport mode of an adsorption tube for capturing volatile organic compounds.
FIG. 7 is a cross-sectional view showing a storage / transportation form of a solid surface volatile organic compound sampling device with a volatilizing gas self-cleaning function.
FIG. 8 is a cross-sectional view of a modification of the sampling device.
FIG. 9 is a cross-sectional view of another modification of the sampling device.
FIG. 10 is an explanatory diagram of a conventional volatile organic matter measurement system.
FIG. 11 is a cross-sectional view illustrating a configuration example of a conventional measurement chamber.
FIG. 12 is a cross-sectional view showing another configuration example of a conventional measurement chamber.
[Explanation of symbols]
10 sampling apparatus, 12 suction tube, 14 quartz tube, 16 suction port, 18 fluorine resin plug, 20 adsorbent, 22 quartz glass filter 24 quartz wool 26 sampling container 28 adsorption tube mounting sleeve 30 volatile chamber 32 quartz glass filter 34 carrier gas supply passage 36 ... Adsorbent, 38 ... Quartz wool, 40 ... Solid surface, 42 ... Carrier gas inlet, 44 ... Heating means, 46, 48 ... Fluororesin stopper

Claims (3)

A method for measuring an organic substance volatilized from a solid surface, wherein an opening of a volatilization chamber formed in a sampling container is brought into contact with the solid surface and sealed, and the organic substance is trapped and removed via an adsorbent in the volatilization chamber. By introducing the carrier gas which has been subjected to the self-cleaning treatment, the organic matter accompanying the carrier gas is adsorbed by the adsorption tube by flowing the carrier gas through the adsorption tube facing the suction port to the volatilization chamber, A method for measuring volatile organic matter, comprising measuring volatile organic matter captured by the adsorption tube. A method for measuring volatile organic matter, wherein the carrier gas adsorbent and the sampling container and the adsorption tube are preliminarily cleaned by heating and sampled. A sampling device for measuring an organic substance volatilized from a solid surface, wherein a volatile chamber is formed at a tip opening side of a sampling container, and a suction tube is detachably mounted inside the sampling container with a suction port facing the volatile chamber. Forming an adsorption tube mounting portion and a carrier gas supply path provided with an adsorbent for trapping organic substances from the carrier gas introduced into the volatilization chamber, and forming a volatilization chamber opening of the sampling container on the solid surface. A sampling device for measuring volatile organic substances, which is capable of measuring volatile organic substances by contacting and sealing and introducing a carrier gas.

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