JPH0462749A - Molecular beam sampling device - Google Patents

Abstract

PURPOSE:To shorten the stopping time of a device caused by blocking of holes by monitoring the blocking of the holes of a primary and a secondary throttle mechanism by means of a block detecting mechanism, and operating a block dissolving mechanism so as to remove the blocking of the holes without disassembling a molecular beam sampling device. CONSTITUTION:The adhesion and deposition of film or powder in the hole part of an orifice 4 invites the reduced inflow of gas into a primary chamber 1. In correspondence with the degree of the reduction of the pressure in the primary chamber 1 caused by this reduced inflow, the degree of the blocking of the hole of the orifice 4 can be monitored. Then laser light 31 is radiated from the laser light source 30 of a block dissolving mechanism so as to dissolve the blocking by evaporating the blocking substance in the hole of the orifice 4. The hole of a clearance 5 is treated in the same manner. Since the blocking of the holes of the orifice 4 and the clearance 5 can be removed without disassembling a molecular beam sampling device, it is unnecessary to do such troublesome adjustments as disassembling and assembling the device, and placing the hole of the orifice 4, the hole of the clearance 5, the small hole of a collimator 6 and an ionization part 101 of a quadrupole mass spectrometry on the same line along the course of molecular beam. Therefore, the time until the spectrometry is resumed can be shortened.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a molecular beam sampling device, and in particular, to shortening the downtime of the device due to blocking of the throttle portions of the first and second throttle mechanisms. This invention relates to a molecular beam sampling device suitable for

[Conventional technology]

In the molecular beam sampling device, the gas on the detection side is analyzed through a first throttle mechanism and a second throttle mechanism.

FIG. 4 is a block diagram of a conventional molecular beam sampling device.

The molecular beam sampling device shown in FIG.

Volume 60 (1984), pages 173 to 187 (In
International Journal of Ma
ss Spectrometry and Ion Pr
occesses, 60 (1984) pp, 173~
187), and the conventional molecular beam sampling device will be explained below with reference to FIG.

The gas to be detected is evacuated through the molecular beam sampling device to the ultimate pressure. The operation will be described below.

Each chamber is evacuated using its own vacuum evacuation system. That is, the gas in the first chamber 1 is evacuated by the first chamber evacuation system 7, the gas in the second chamber 2 is evacuated by the second chamber evacuation system 8, and the gas in the third chamber 3 is evacuated. The third chamber is evacuated using the vacuum evacuation system 9. At this time, the first chamber vacuum gauge 14 is provided to monitor the pressure in each chamber. Second chamber vacuum gauge 15. The pressure in the third chamber 3 measured by the third chamber vacuum gauge 16 is lower than the pressure at which the quadrupole mass spectrometer 10, which is a detector installed in the third chamber 3, can fully operate. Check that the ultimate pressure is reached.

Next, the operation when analyzing the gas on the detection side using the molecular beam sampling device will be described. The gas to be detected is introduced into the first chamber through an orifice 4 having an extremely small hole. The first chamber 1 is evacuated by a first chamber vacuum evacuation system 7 so that the pressure in the first chamber 1 is sufficiently lower than the pressure in the area where the gas is present on the detection side. Therefore, the gas that has passed through the orifice 4 becomes a free jet within the first chamber 1.

Since the gas introduced at this time undergoes adiabatic expansion, the temperature of the gas is significantly lowered, and intermediate active species, which would normally be generated by reactions that easily decompose, are also preserved.

Note that the pressure state of the first chamber 1 is measured by a first chamber vacuum gauge 14.

During this free jet flow, the skimmer 5 is moved to an appropriate position via the skimmer moving mechanism 11, and a portion of the free jet flow is guided to the second chamber 2.

The inside of the second chamber 2 is evacuated by the second chamber evacuation system 8 so that the pressure is sufficiently lower than that of the first chamber 1, and the pressure state is measured by the third chamber vacuum gauge 15. There is.

The gas introduced into the second chamber 2 through the gap 5 becomes a molecular beam without gas collisions. This molecular beam becomes a molecular beam that is interrupted by a chopper 12 having a plurality of notches on a rotating disk.

Also, at this time, a signal is output from the detector 19 for detecting when the molecular beam passes through the chopper 12, and is used for signal processing of the signal from the quadrupole mass spectrometer 10.

A portion of the intermittent molecular beam is introduced into the third chamber 3 through a collimator 6 provided on the wall of the third chamber 3. Third room 3
The interior of the chamber is evacuated by a third chamber vacuum evacuation system 9 to a pressure sufficient to operate the quadrupole mass spectrometer 10, and the pressure state is measured by a third chamber vacuum gauge 16.

Part of the intermittent molecular beam was taken into the quadrupole mass spectrometer 10 for analysis, and the rest passed through the quadrupole mass spectrometer ionization section 101 and was introduced into the third chamber 3. The light passes through the small hole 17 on the opposite side and is irradiated onto the third chamber molecular beam irradiation surface 18. Solid line 20 indicates a molecular line.

[Problem to be solved by the invention]

In the above conventional technology, the atmosphere of the gas on the detection side is
For example, CV D (Chemical Vapor
When a film or powder is produced, such as by a reaction (deposition) or an etching reaction, when the gas on the detection side is analyzed using a molecular beam sampling device, the solids generated by the reaction described above can be detected. adheres to and accumulates in the orifice 4 or the hole in the gap 5,
Ultimately, since the hole is blocked, the gas to be detected cannot be introduced into the molecular beam sampling device, making analysis impossible. Therefore, the device is disassembled, the blockage of the hole in the orifice 4 or the gap 5 is removed, and the device is reassembled. There was a problem in that it required adjustment to place the 101 on the same straight line (alignment), and it took a long time to restart the analysis.

The purpose of the present invention is to
Another object of the present invention is to provide a molecular beam sampling device that can shorten the downtime of the molecular beam sampling device due to blockage of the hole in the gap 5.

[Means to solve the problem]

In order to achieve the above object, the configuration of the molecular beam sampling device according to the present invention is such that at least the gas on the detection side is
It includes a first throttle mechanism that ejects the gas from the side where the gas is present to the side with lower pressure to form a free jet, and a first evacuation system that lowers the pressure in the chamber than the gas pressure on the detected side. a first chamber adjacent to the first chamber, at least a second throttle mechanism that introduces the free jet formed by the first throttle mechanism to form a molecular beam; a second evacuation system that adjusts the molecular beam, a molecular beam intermittent mechanism that periodically intermittents the molecular beam formed by the second aperture mechanism, and a molecular beam intermittent mechanism that detects that the molecular beam has passed through the molecular beam intermittent mechanism. a second chamber comprising means, a chamber adjacent to the second chamber, a small hole for introducing at least a portion of the interrupted molecular beam formed in the second chamber, and a small hole for introducing at least a portion of the interrupted molecular beam formed in the second chamber; A molecular analyzer that analyzes the components in the molecular beam, a mobile device that adjusts the relative position of the analyzer and the molecular beam, and a third chamber equipped with a third vacuum exhaust system that adjusts the pressure in the chamber. The line sampling device is characterized in that it is provided with a blockage elimination mechanism that removes blockages in the first aperture mechanism and the second aperture mechanism.

[Effect]

The working of the above technical means is as follows.

When analyzing the gas on the detection side using a molecular beam sampling device, the blockage detection mechanism monitors the blockage of the holes in the first aperture mechanism and the second aperture mechanism, and when the blockage of the hole is detected, the analysis starts. is stopped, the blockage elimination mechanism is activated, and the blockage in the hole of the first throttle mechanism or the second throttle mechanism is removed. At this time, since there is no need to disassemble the molecular beam sampling device, the downtime of the device due to blockage of the hole in the first throttle mechanism or the second throttle mechanism caused by the gas on the detection side is shortened.

〔Example〕

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

FIG. 1 is a schematic configuration diagram of a molecular beam sampling apparatus according to an embodiment of the present invention.

In Figure 1, 1 is the first chamber, 2 is the second chamber, 3 is the third chamber, and 4 is the gas on the side to be detected that is ejected from the side where this gas is present to the first chamber 1 where the pressure is low. The orifice 5 associated with the first throttling mechanism that forms the free jet flows into the second chamber 2.
6 is a collimator having a small hole for introducing a part of the intermittent molecular beam formed in the second chamber; a first chamber vacuum evacuation system that lowers the pressure of the gas to be lower than the gas pressure on the detected side;
8 is a second chamber vacuum exhaust system that adjusts the pressure inside the second chamber 2;
9 is a third chamber vacuum exhaust system that adjusts the pressure inside the third chamber 3;
10 is a quadrupole mass spectrometer that analyzes the components of the molecular beam introduced into the third chamber 3; 101 is an ionization section of the quadrupole mass spectrometer; 11 is a section between the orifice 4 and the gap 5; A gap moving mechanism for adjusting the distance, 12 is a gap 5
A chopper 13 is a quadrupole mass spectrometer moving mechanism that adjusts the relative position of the quadrupole mass spectrometer 10 and the molecular beam. 14 is a first chamber vacuum gauge that measures the pressure state of the first chamber 1; 15 is a third chamber vacuum gauge that measures the pressure state of the second chamber 2; and 16 is a vacuum gauge that measures the pressure state of the third chamber 3. A third chamber vacuum gauge 19 is a detector for detecting that the molecular beam has passed through the chopper 12, and 20 is a molecular beam.

3o is a blockage elimination mechanism made of a laser light source 30. 31 is a laser beam.

The operation of this device will be explained below.

Before introducing the gas to be detected into the molecular beam sampling device, the device is evacuated to the ultimate pressure.

The first chamber 1 is evacuated by a first chamber evacuation system 7, the second chamber 2 is evacuated by a second chamber evacuation system 8, and the third chamber 3 is evacuated by a third chamber evacuation system 9. At this time, the first chamber vacuum gauge 14 is provided to monitor the pressure in each chamber. Second chamber vacuum gauge 15
．． The pressure in the third chamber 3 measured by the third chamber vacuum gauge 16 is lower than the pressure at which the quadrupole mass spectrometer 10, which is a detector installed in the third chamber 3, can fully operate. Confirm that the ultimate pressure in chamber 3 is reached.

Next, the operation when analyzing the gas on the detection side using the molecular beam sampling device will be described. The gas to be detected is introduced into the first chamber 1 through the orifice 4 . The first chamber 1 is evacuated by a first chamber vacuum evacuation system 7 so that the pressure in the first chamber 1 is sufficiently lower than the pressure in the area where the gas is present on the detection side.

Therefore, the gas that has passed through the orifice 4 expands adiabatically and becomes a free jet. At this time, the temperature of the gas is significantly lowered, and intermediate active species, which would normally be produced by reactions that easily decompose, are also preserved.

Note that the pressure state of the first chamber 1 is measured by a first chamber vacuum gauge 14.

During this free jet, the clearance 5 is moved to an appropriate position via the clearance moving mechanism 11, and a part of the free jet is transferred to the second chamber 2.
lead to.

The inside of the second chamber 2 is evacuated by the second chamber evacuation system 8 so that the pressure is sufficiently lower than that of the first chamber 1.
The pressure state is measured by the third chamber vacuum gauge 15.

The gas introduced into the second chamber 2 through the gap 5 becomes a molecular beam in which gas molecules do not collide with each other. This molecular beam becomes a molecular beam that is interrupted by a chopper 12 having a plurality of notches on a rotating disk. Also, a detector 19 for detecting when the molecular beam passes through the chopper 12 at this time.
A signal is output from the quadrupole mass spectrometer 10 and used for signal processing of the signal of the quadrupole mass spectrometer 10.

A portion of the intermittent molecular beam is introduced into the third chamber 3 through a collimator 6 provided on the wall of the third chamber 3. Third room 3
The interior of the chamber is evacuated by a third chamber vacuum evacuation system 9 to a pressure sufficient to operate the quadrupole mass spectrometer 10, and the pressure state is measured by a third chamber vacuum gauge 16.

A portion of the intermittent molecular beam is taken into the quadrupole mass spectrometer 10 and analyzed, and the rest passes through the quadrupole mass spectrometer ionization section 101. Solid line 20 indicates a molecular line. At this time, blockage of the orifice 4 and the gap 5 is monitored by the blockage detection mechanism. In this embodiment, the first chamber vacuum gauge 14 and the third chamber vacuum gauge 15 correspond to the blockage detection mechanism.

For example, if a film or powder caused by the gas on the test side adheres or accumulates in the hole of the orifice 4, the amount of gas flowing into the first chamber 1 will decrease. This reduces the gas load on the first chamber evacuation system 7 and lowers the pressure inside the first chamber 1. The degree of blockage of the orifice 4 can be monitored depending on the degree of pressure drop.

When the orifice 4 is completely closed, the pressure in the first chamber 1 becomes the ultimate pressure before the gas to be detected is introduced. At this time, the laser light source 30 of the blockage elimination mechanism emits a laser beam 31 to vaporize the substance blocking the hole in the orifice 4 and eliminate the blockage. Furthermore, if a film or powder caused by the gas on the detection side is deposited or attached to the hole in the gap 5, the amount of gas flowing into the second chamber 2 will be reduced. This reduces the gas load on the second chamber evacuation system 8 and lowers the pressure inside the second chamber 2. Depending on the degree of this pressure drop, the gap 5
The degree of blockage of the hole can be monitored. When the hole in the gap 5 is completely closed, the pressure in the second chamber 2 becomes the ultimate pressure before introducing the gas to be detected. At this time, similarly to when the hole in the orifice 4 is blocked, the laser light source 30 of the blockage elimination mechanism emits a laser beam 31 to vaporize the substance blocking the hole in the gap 5 and eliminate the blockage. Blockage of the hole in the orifice 4 or the gap 5 by film or powder caused by the gas on the detection side can be removed without disassembling the molecular beam sampling device. Since it is not necessary to adjust the holes, the holes in the gap 5, the small holes in the collimator 6, and the quadrupole mass spectrometer ionization unit 101 to be on the same straight line, the time required to restart the analysis can be shortened. Further, in this embodiment, the blockage elimination mechanism is composed of a laser light source 30,
When assembling and adjusting the molecular beam sampling device, the hole of the orifice 4, the hole of the gap 5, the small hole of the collimator 6, and the quadrupole mass spectrometer ionization section 101 are placed on the same straight line (
It has the characteristic that it can also be used as a means for (obtaining alignment). Furthermore, the installation position of the laser light source of the blockage elimination mechanism does not have to be on the bottom of the third chamber 3 of the molecular beam sampling device as in this embodiment; for example, it may be placed on the sample gas side as shown in FIG. You may.

FIG. 3 is a block diagram of a molecular beam sampling device according to another embodiment of the present invention.

In this embodiment, a photodiode 4 is used as the blockage detection mechanism.
0, a laser light source 30 is used as the blockage elimination mechanism. The effect will be described below. If the hole in the orifice 4 or the hole in the gap 5 is blocked by a film or powder caused by the gas on the detection side, the laser beam 31 will no longer be continuously incident on the photodiode 40 . Therefore, the shutter 41 is operated to shield the photodiode 40.

Next, the intensity of the laser beam 30 is increased to vaporize the material blocking the hole of the orifice 4 or the hole of the gap 5, thereby removing the blockage. Next, the output of the laser light source 30 is lowered and the shutter 41 is activated so that the laser light 31 enters the photodiode 40. This allows orifice 4
Confirm that the blockage in the hole or the hole in gap 5 has been removed.

Furthermore, in this embodiment, since the laser light source 30 and the photo die cart 40 also serve as a detector for detecting that the molecular beam 20 has passed through the chopper 12, there is no need to provide a detector in the second chamber 2. The structure inside the second chamber 2 becomes simple.

〔Effect of the invention〕

According to the present invention, the blockage detection mechanism monitors the blockage of the holes of the first throttle mechanism and the second throttle mechanism, and when the blockage of the holes is detected, the blockage elimination mechanism is activated, and The blockage of the hole in the second throttle mechanism can be removed without disassembling the molecular beam sampling device. It is possible to shorten the downtime of the equipment due to blockage.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a molecular beam sampling device according to one embodiment of the present invention, FIGS. 2 and 3 are block diagrams of a molecular beam sampling device according to other different embodiments of the present invention, and FIG. 1 is a block diagram of a conventional molecular beam sampling device. 1. First chamber, 2. Second chamber, 3. Third chamber, 4. Orifice, 5. Clearance, 6. Collimator, 7. First chamber vacuum exhaust system, 8. Second chamber. Vacuum exhaust system, 9. Third chamber vacuum evacuation system, 10. Quadrupole mass spectrometer, 11. Clearance moving mechanism, 12... Chopper, 13... Quadrupole mass spectrometer moving mechanism, 14・First chamber vacuum gauge, 15...Third chamber vacuum gauge, 16...Third chamber vacuum gauge, 17...Small hole, 18...
... Second plan molecular beam irradiation surface, 19... Detector, 20...
Molecular beam, 30... Laser light source, 31... Laser light, 4
0...Photodiode, 41...Shutter, 101
...Quadrupole mass spectrometer ionization section.

Claims (1)

[Claims] 1. At least a first throttling mechanism that injects the gas on the detection side from the side where the gas is present to a low pressure chamber to form a free jet, and a first chamber equipped with a first evacuation system that makes the gas pressure lower than the gas pressure on the detected side; and a chamber adjacent to the first chamber, the free jet being formed by at least the first throttle mechanism. a second constriction mechanism that introduces a molecular beam to form a molecular beam, a second evacuation system that adjusts the pressure in the chamber, and a molecular beam intermittent mechanism that periodically interrupts the molecular beam formed by the second constriction mechanism. , and a second chamber equipped with means for detecting that the molecular beam has passed through the molecular beam intermittent mechanism, and an analyzer for analyzing components in the intermittent molecular beam formed in the second chamber, and In a molecular beam sampling device comprising a third chamber equipped with a third evacuation system for adjusting the pressure in the chamber, the gas on the detection side of the constriction part of the first constriction mechanism or the second constriction mechanism is A molecular beam sampling device comprising a blockage detection mechanism that detects a blockage caused by the blockage, and a blockage elimination mechanism that removes the blockage.