JPH11160299A - Apparatus for capturing semiconductor contaminant substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To analyze a contaminant substance with high sensitivity by efficiently capturing only a contaminant to be a problem in a semiconductor industry in an apparatus for capturing a semiconductor contaminant substance contained in a clean room air. SOLUTION: Silicon powder 3 comminuted to 100 to 500 μm is charged in a quartz tube 2. When a pump 4 is driven, the air is sucked from an air suction port 1. At this time, an ester compound, siloxane compound or the like is adsorbed to the powder. And, the compound which does not become a problem in a semiconductor industry is not adsorbed, but discharged together with the air. Thereafter, the tube is heated by a heater, and the substance is introduced to a cold trap. This is cooled by liquid nitrogen, then abruptly heated by a high frequency wave, and hence the substance is introduced to a separation column of a gas chromatograph.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for collecting a sample when performing gas chromatographic analysis of a semiconductor contaminant.

In particular, the present invention is characterized by providing high analytical sensitivity by selectively and efficiently collecting contaminants which affect the characteristics of semiconductors.

[0003]

2. Description of the Related Art Conventionally, as a method for trapping pollutants in air, air is passed through a glass tube or quartz tube filled with an adsorbent called glass or wool, and the contaminants are adsorbed there. After collection, there is a method in which the glass tube or the quartz tube itself is heated, and the adsorbed contaminants are introduced into a gas chromatograph for analysis. This method is known and is the most frequently used method.

However, this method is excellent as a general environmental analysis method because it absorbs all substances contained in the air itself, but has several problems as a collection method in the semiconductor industry. doing. Pollutants that pose a problem in the semiconductor industry are substances that selectively adsorb to silicon among substances contained in air, and ester-based compounds and siloxane-based compounds are representative thereof. In the conventional method, it is hardly adsorbed on silicon, and furthermore, it adsorbs a large amount of a substance present in a clean room, so that the collection efficiency of the substance that must be selectively adsorbed is reduced,
There was a problem that the detection sensitivity of analysis was reduced.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently collecting only contaminants which are present in a trace amount in the air and which selectively adsorb to silicon, and which have high detection sensitivity. Aim.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for trapping semiconductor contaminants in air, which is an apparatus for trapping air by passing air through a sampling tube filled with silicon powder as an adsorbent.

[0007]

By using the trapping device of the present invention, the detection sensitivity of semiconductor contaminants in gas chromatography / mass spectrometry can be increased by one.
It becomes possible to make it 0 times or more.

[0008]

Embodiments of the present invention will be described below. FIG. 1 is a diagram showing the trapping method of the present invention. In the present invention, a quartz tube 2 is filled with silicon powder 3 crushed to 100 to 500 μm. One of the quartz tubes is used as an air suction port 1 and the other is connected to a pump 4 to constitute the collection system of the present invention.

When the pump 4 of the system is driven, air is sucked from the air inlet 1 and passes through the silicon powder 3. At this time, ester-based compounds and siloxane-based compounds that are selectively adsorbed in the air, especially on silicon, are efficiently adsorbed on the silicon powder, and do not pose a problem in the semiconductor industry and are unnecessary compounds contained in the air in large amounts. Is not adsorbed and is discharged as exhaust gas together with air. Silicon powder 3
Since almost no compounds that do not cause a problem in the semiconductor industry are adsorbed, the adsorption of the compound that causes a problem is possible until the silicon powder 3 is saturated. As a result, a larger amount of trapping can be performed than in the past. As the silicon powder used here becomes finer, the surface area increases, so that a large amount of adsorption is possible. On the other hand, the flow rate of air decreases, so that it becomes difficult to inhale a large amount of air. Since the efficiency of adsorption by the compound changes according to the speed of passing through the silicon powder 3, the diameter of the silicon powder is optimally 100 to 500 μm. At a flow rate of 1 liter / minute, the collecting operation is completed with a total of 20 liters.

After being collected by the above-mentioned collecting method, the quartz tube 2 filled with the silicon powder 3 is heated as shown in FIG.
Attach it while surrounded by 2. Helium gas is flowed through the quartz tube 11 filled with silicon powder at a flow rate of 50 cc / min and heated to 400 ° C. for 30 minutes by the heater 12, whereby the contaminants adsorbed on the silicon powder 3 are completely desorbed. Be guided. At this time, contaminants are completely trapped in the cold trap 13 by cooling the liquid nitrogen cooling unit and the heater unit 14 to -40 ° C. with liquid nitrogen. Next, when the liquid nitrogen cooling unit and the heater unit 14 are rapidly heated to 250 ° C. by high frequency, concentrated contaminants are desorbed from the cold trap and the gas chromatograph unit 1 is removed.
5 into the separation column 16. The contaminants are separated for each component in the separation column 16 and the mass spectrometer 17
, And mass spectrometry is performed to enable qualitative and quantitative determination.

[0011]

As described above, the use of the trapping device of the present invention makes it possible to increase the detection sensitivity of semiconductor contaminants by gas chromatography / mass spectrometry to 10 times or more.

[Brief description of the drawings]

FIG. 1 is a view showing an apparatus for collecting semiconductor contaminants according to an embodiment of the present invention.

FIG. 2 is a view showing a method of analyzing semiconductor contaminants according to an embodiment of the present invention.

FIG. 3 is a diagram showing an apparatus for collecting semiconductor contaminants according to a conventional embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air inlet 2 Quartz tube 3 Silicon powder 4 Pump 5 Exhaust 11 Quartz tube filled with silicon powder 12 Heater 13 Cold trap 14 Liquid nitrogen cooling unit and heater unit 15 Gas chromatograph unit 16 Separation column 17 Mass detector 21 Air inlet 22 glass tube 23 glass wool 24 pump 25 exhaust

Claims (1)

[Claims] 1. A method for collecting semiconductor contaminants in air, wherein the air is collected through a sampling tube filled with silicon powder as an adsorbent and collected.