JP3395471B2 - Trace organic matter analyzer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a trace organic substance analyzer used for analyzing and measuring trace organic substances on the surface of a substrate such as a silicon wafer. 2. Description of the Related Art Generally, in the manufacture of semiconductor devices, various kinds of contamination occur in products or intermediate products during the manufacturing process, and some adverse effects are exerted on the operation characteristics of the obtained devices. There is also some pollution. One of the contaminants that adversely affects the operation characteristics of such a device is a trace amount of organic substances adsorbed on the silicon wafer surface. The contamination by the organic matter occurs even when the silicon wafer is left in a dust-free atmosphere or is simply stored in a plastic case. Therefore, conventionally, in order to grasp the presence or absence of such organic substances and the amount thereof, and to eliminate the influence of contamination due to the adsorption of the organic substances, the organic substances adsorbed on the silicon wafer surface are analyzed. FIG. 3 is a diagram showing an example of a trace organic substance analyzer used for such organic substance analysis. In FIG. 3, reference numeral 1 denotes a trace organic substance analyzer (hereinafter, abbreviated as an analyzer). The analyzer 1 is configured so that a silicon wafer A serving as an analysis sample can be analyzed without being cleaved before analysis. The analyzer 1 is a thermal desorption gas chromatography / mass spectrometer (a thermal desorption GC / MS device). ), A sample setting chamber 2 for setting a silicon wafer A serving as an analysis sample;
And the analyzer main body 3 connected to the sample setting chamber 2. [0004] The sample setting chamber 2 has an opening 2a for allowing the silicon wafer A to enter and exit from the front surface thereof, and a heating chamber 4 for heating the silicon wafer A therein. A silicon wafer A is placed on the substrate, and the silicon wafer A is heated in this state. The analyzer main body 3 includes a sample gas supply pipe 5 drawn out of the sample setting chamber 2 from a position immediately above the heating chamber 4 to the outside of the sample setting chamber 2, and a concentrator 6 connected to the sample gas supply pipe 5. And a gas chromatograph (capillary column) 7 connected to the concentrating device 6, and a mass spectrometer 8 connected to the gas chromatograph 7. The concentrator 6 includes a trap tube 9 and a needle heater 10. In order to analyze the organic matter adsorbed on the silicon wafer A by the analyzer 1 having such a configuration, first, the silicon wafer A is placed on the heating chamber 3 and then an electric furnace, an infrared lamp, etc. Is heated by the heating means. Then, the gas composed of organic substances desorbed from the silicon wafer A passes through the sample gas supply pipe 5, is concentrated by the concentration device 6 including the trap tube 9 and the needle heater 10, and is sequentially introduced into the gas chromatograph 7 and the mass spectrometer 8. An analysis is made. [0006] However, the analyzer 1 has the following inconveniences. When performing the analysis, when placing the silicon wafer A on the heating chamber 4 in the sample setting chamber 2, the silicon wafer A is usually taken out of the storage case containing the silicon wafer A as the analysis sample, and the silicon wafer A Is placed on the heating chamber 4, but when the silicon wafer A is taken out of the storage case, the silicon wafer A is naturally exposed to the atmosphere (room air). Exposure time to this atmosphere is usually about 1 minute,
The organic gas in the atmosphere is adsorbed on the surface of the silicon wafer A within this extremely short time. In particular, in a closed system such as in a clean room, the adsorption speed is high. Therefore, the organic gas adsorbed prior to the analysis as described above results in a state in which organic substances other than the intended purpose are added to the data obtained by the analysis, resulting in low reliability of the data. It is. [0007] Incidentally, when the silicon wafer A was taken out of the storage case and analyzed for organic substances on the surface by the analyzer 1 shown in FIG.
The result as shown in (a) was obtained. As shown in FIG. 2A, substances such as propanoic acid ester and DOP (di-2-ethylhexyl phthalate) are detected from the surface of the silicon wafer A in addition to the substance adsorbed on the surface of the silicon wafer A from the beginning. It has been done. These substances are organic gases mainly present in the air in the clean room or plasticizers volatilized from plastics, and have extremely high adsorptivity. As described above, in the conventional analyzer 1, the obtained data is the data to which the organic substances other than the original purpose are added, and it is very difficult to compare the trace organic substances. [0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to remove the analysis sample from the atmosphere without exposing the analysis sample to the atmosphere until the analysis sample is placed on the heating chamber. It is an object of the present invention to provide a trace organic matter analyzer that is exposed only to the organic matter. According to the present invention, there is provided a trace organic substance analyzer, comprising: a sample setting chamber having an opening through which an analysis sample enters and leaves; a sample setting chamber connected to the sample setting chamber; An analysis device main body for analyzing organic matter, a preparation chamber provided in communication with an opening of the sample installation chamber, and a clean air introduction mechanism for introducing clean air passed through an organic gas removal filter into the preparation chamber. Is provided as means for solving the above problem. According to this trace organic substance analyzer, since the clean air introduction mechanism for introducing the clean air that has passed through the organic gas removal filter into the preparation room is provided, the analysis sample is stored in the storage case in the preparation room. If the analysis sample is placed in the sample installation room in this state, the analysis sample passes through the organic gas removal filter without being exposed to the atmosphere, and is thus converted into clean air from which the organic gas has been removed. Because only the exposure is performed, the analysis sample is prevented from adsorbing new organic substances due to the analysis operation before the analysis of the organic substances. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a trace organic matter analyzer of the present invention will be described in detail. FIG. 1 is a diagram showing an embodiment of a trace organic matter analyzer according to the present invention.
Numeral 0 denotes a trace organic substance analyzer (hereinafter, abbreviated as an analyzer) preferably installed in a clean room, and is provided by a thermal desorption gas chromatography / mass spectrometer similarly to the analyzer 1 shown in FIG. It constitutes the main body 3 of the analyzer. Note that the same components as those of the analyzer 1 shown in FIG. 3 of the analyzer 20 shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the analyzer 20 shown in FIG. 1 and the analyzer 1 shown in FIG. 3 is that a preparation chamber 21 is provided in communication with the opening 2a of the sample installation chamber 2 and that the analyzer 20 passes through an organic gas removal filter. The point is that a clean air introduction mechanism 22 for introducing clean air into the preparation chamber 21 is provided. In the analyzer 20, a preparation chamber 21 is provided on the opening 2a side of the sample installation chamber 2. The preparation chamber 21 includes two side walls 2b, 2
b, a pair of side walls 21a, 21 provided in a continuous state
and an organic gas removal filter unit 23 which is bridged between upper ends of the side walls 21a and 21a and also serves as a top plate.
And a door (not shown) attached to the opening on the side opposite to the sample setting chamber 2 formed by the side walls 21a, 21a and the organic gas removal filter unit 23. That is, the preparation room 21 is provided in the sample setting room 2
The analysis sample (for example, a silicon wafer) is taken out of the storage case by a person in the preparation chamber 21 as described later, and is directly It is arranged so that it can be placed on top. Therefore, the preparation room 21 is large enough to allow one person to enter therein, and in such a state, it is possible to perform operations such as taking out the analysis sample and placing it on the heating chamber 4 as described above. Specifically, the height from the floor on which the preparation room 21 is installed to the ceiling (the lower surface of the organic gas removal filter unit 23) is about 1.8 to 2.0 m, and the width between the side walls 21a, 21a is The depth is about 0.8 to 1.2 m and the depth is about 0.6 to 1.0 m. The organic gas removing filter unit 23 comprises a unit main body 24 having a space therein, and an organic gas removing filter (not shown) housed in the space of the unit main body 24. A suction port (not shown) is formed on the upper surface of the unit body 2.
An air supply port (not shown) is formed on the lower surface of 4 so as to face the preparation chamber 21. The organic gas removal filter is generally called a chemical filter, and is formed of activated carbon fibers. Specifically, for example, a honeycomb type filter CH series [brand name] manufactured by Kondo Kogyo Co., Ltd.
And dust removal / combination type filter CM series (trade name), and Puracol (trade name) manufactured by Nitta Corporation. The organic gas removing filter unit 23 in which such an organic gas removing filter is housed in the unit main body 24 has an internal part such that an air flow path is formed from an intake port of the unit main body 24 to an air supply port. The organic gas removal filter is formed in the flow path without any gap. Then, with such a configuration, the organic gas removal filter unit 23 allows the air sucked from the suction port to pass through the organic gas removal filter, thereby removing a small amount of the organic gas present in the air to obtain clean air. Clean air is supplied into the preparation chamber 21 from an air supply port. A fan 25 indicated by a two-dot chain line in FIG. 1 is mounted on the organic gas removal filter unit 23 in a state of communicating with its suction port. This fan 25
It is configured to inhale external air and send the inhaled air into the intake port. The fan 25 and the organic gas removal filter unit 23 constitute a clean air introduction mechanism 22 in the present invention. In order to analyze the organic matter adsorbed on the silicon wafer A by the analyzer 20 having such a configuration,
First, the fan 25 is operated, and the air in the room where the analyzer 20 is installed, such as a clean room, is sucked. Then, the air sucked into the fan 25 flows into the suction port of the organic gas removal filter unit 23, and further passes through the organic gas removal filter in the organic gas removal filter unit 23, where the organic gas is removed, and becomes clean air. And is blown into the preparation chamber 21 from the air supply port. When the clean air is blown into the preparation room 21 in this manner, the air in the preparation room 21 is exhausted from, for example, a gap between the door and the floor surface, whereby the inside of the preparation room 21 is replaced by the clean air. Then, after the inside of the preparation room 21 is replaced with the clean air, the operator enters the preparation room 21 with the storage case storing the silicon wafer A while the operation of the fan 25 is continued. At this time, the door is naturally opened to enter the preparation room 21, but since the pressure in the preparation room 21 is higher than the atmospheric pressure due to the operation of the fan 25, the preparation room is opened and closed. The inflow of the air outside 21 into the preparation chamber 21 is almost negligible.
In addition, if necessary, the operator does not start the operation immediately after entering the preparation room 21, but prepares the preparation room 2 with the opening and closing of the door.
It may be on standby until the air that has flowed into 1 is replaced with clean air again. Next, the silicon wafer A is taken out of the storage case, and the silicon wafer A is placed on the heating chamber 4. At this time, the removed silicon wafer A is
Since only the clean air from which the organic gas has been removed is exposed in the preparation chamber 21, it is possible to prevent the organic substance from being newly adsorbed with this operation. After the silicon wafer A is placed on the heating chamber 4 in this manner, the subsequent operation is performed in the same manner as in the conventional case, and the trace organic substances on the surface of the silicon wafer A are analyzed. By the way, the analyzer 20 shown in FIG.
When the silicon wafer A processed in the same step as the silicon wafer A for which the analysis result shown in FIG. 2A was obtained was analyzed, as shown in FIG.
P (di-2-ethylhexyl phthalate) and the like are hardly detected, and only the intended organic substance is detected. Therefore, the obtained data excludes data of the organic substance other than the intended purpose accompanying the analysis operation. It was confirmed that it was possible. Therefore, in the analyzer 20, the organic substances adsorbed on the surface of the silicon wafer A serving as an analysis sample can be accurately analyzed without analyzing other organic substances together with the analysis operation. The reliability of the analysis data can be improved, so that the state of contamination of the silicon wafer A with organic substances can be accurately grasped. In the above example, the analyzer main body 3 is constituted by a thermal desorption gas chromatography / mass spectrometer. However, the present invention is not limited to this. For example, an X-ray photoelectron spectrometer, The analyzer main body can also be constituted by an infrared spectrometer, a time-of-flight secondary ion mass spectrometer, a thermal desorption mass spectrometer, or the like. In such a case, these X-ray photoelectron spectrometers, infrared spectrometers, time-of-flight secondary ion mass spectrometers, and thermal desorption mass spectrometers cannot separate each substance from the analysis data. When used as the main body of the analyzer in the apparatus 1, when an organic gas in the atmosphere is adsorbed on the analysis sample (silicon wafer A), organic substances other than the original purpose are added as they are, and the original organic substance and the analysis operation are performed. However, when the above devices are used as the main body of the analyzer in the present invention, the organic materials other than the original purpose accompanying the analysis operation are excluded from the data obtained as described above. Therefore, analysis data having sufficient reliability can be obtained. In the above example, the clean air introduction mechanism 22
To the organic gas removal filter unit 23
5, the fan 25 and the organic gas removal filter unit 23 may be connected by piping, for example, and air from which dust or the like has been sufficiently removed may flow into the organic gas removal filter unit 23. In the above-described example, the organic gas removal filter unit 23 is disposed at a position to be a ceiling of the preparation room 21 and functions as a top plate. You may function as a side wall. Further, in the above-mentioned example, the preparation room 21 is made wide so that a person can enter and leave it. However, for example, the preparation room is provided with a window having a space through which a storage case can be put in and out and an operation window into which only hands can be put. It shall be a narrow space provided,
The operation may be performed by putting only the hand in the preparation room.
Furthermore, in the above example, an example in which a silicon wafer was used as an analysis sample was described.However, the trace organic substance analyzer of the present invention is not limited to this, and is applicable to all samples for analyzing trace organic substances. Applicable. As described above, the trace organic substance analyzer of the present invention is provided with the clean air introduction mechanism for introducing the clean air that has passed through the organic gas removal filter into the preparation room. If the analysis sample is taken out of its storage case in the preparation room and the analysis sample is set in the sample setting room in that state, the analysis sample is not exposed to the atmosphere but only to the clean air. Therefore, it is possible to prevent the new organic substance from being adsorbed to the analysis sample due to the analysis operation, thereby improving the reliability of the analysis data.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of a trace organic substance analyzer of the present invention. FIG. 2 is a diagram showing an analysis result by a thermal desorption gas chromatography / mass spectrometer (a thermal desorption GC / MS device), (a) is a diagram showing an analysis result by a conventional analyzer, (b) FIG. 4 is a view showing an analysis result by the analyzer of the present invention. FIG. 3 is a schematic configuration diagram of a conventional trace organic substance analyzer. [Description of Signs] 2 Sample setting chamber 2a Opening 3 Analyzer main body 20 Trace organic substance analyzer 21 Preparation chamber 22 Clean air introduction mechanism 23 Organic gas removal filter unit 25 Fan

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI G01N 30/16 G01N 30/16 K 30/72 30/72 A 30/88 30/88 C H01L 21/66 H01L 21/66 L (56) References JP-A-7-83808 (JP, A) JP-A-5-57136 (JP, A) JP-A-62-11132 (JP, A) JP-A-60-190860 (JP, A) JP-A-9-43211 (JP, A) JP-A-7-124435 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 1/00-1/44 G01N 27/62 G01N 30/00-30/96 H01L 21/66 JICST file (JOIS)

Claims (1)

(1) A sample installation chamber having an opening through which an analysis sample enters and exits, and an analysis connected to the sample installation chamber for analyzing organic matter in the analysis sample. in trace organics analyzer including an apparatus body, by communicating with the opening of the sample installation room, the analytical sample
Operation to take out from storage case and install in the sample installation room
And a clean air introduction function for introducing clean air that has passed through the organic gas removal filter into the preparation chamber.