JP2004311446A - Vacuum chamber with gas analyzer, baking method of vacuum chamber with gas analyzer, and analysis method of residual gas in vacuum chamber with gas analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum chamber with a gas analyzer provided with a quadruple mass spectrometer for measuring under high temperature conditions without deteriorating the sensitivity and to provide a baking method of the vacuum chamber with the gas analyzer and an analysis method of the residual gas in the vacuum chamber with the gas analyzer. <P>SOLUTION: An ion source part, a quadrupole part and a detecting part are inserted in a flange of the vacuum chamber 18, the vacuum chamber inside is hermetically sealed by a hermetical seal connection part 17, and a control part 14, the hermetical seal connection part 17 and an analyzer tube are connected together by a signal cable 16. A cooling block 44 is closely attached surrounding the outer circumferential part of the connection part between the flange of the vacuum chamber 18 and the hermeticaly sealed connection part 17, its inside is disposed with a cooling pipe, and a cooling medium is introduced therein. Even if the vacuum chamber 18 is heated by a baking panel 46, the connection part is locally cooled by the cooling block 44 so as to be measured even under the high temperature conditions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer that performs measurement under high temperature conditions, a method for baking the vacuum chamber with a gas analyzer, and a method for analyzing residual gas in the vacuum chamber with a gas analyzer. .

  The device configuration of the quadrupole mass spectrometer is roughly classified into an ion source unit, a quadrupole unit, a detection unit, and a control unit. The ion source, quadrupole and detector are operated in a vacuum and are usually connected to the controller via a vacuum flange. The gas inside the vacuum chamber is ionized by the ion source unit, and the ionized gas is guided and detected by the quadrupole unit by applying an electric field to the detection unit to analyze the residual gas in the vacuum chamber. Do.

  Since the control unit is a component in the atmosphere, it is connected to the above-described analysis tube via a vacuum flange, and has no heat resistance including the electronic circuit unit, the cable and the circuit, and must be used at about 100 ° C. or less. Therefore, when the temperature of each device to which the quadrupole mass spectrometer is attached is raised to a high temperature, a control unit having no heat resistance must be removed depending on the temperature, and gas analysis during heating becomes impossible. For example, when baking an ultra-high vacuum compatible vacuum chamber at a temperature of about 200 ° C. by baking operation or the like, the analysis tube section of the connected quadrupole analyzer is also heated to 200 ° C. The control unit connected to is removed, and the residual gas in the vacuum chamber cannot be analyzed. Therefore, for example, if a gas leaks during heating, it cannot be detected immediately and cannot be dealt with immediately. If there is a leak, after the baking, the device is cooled and then a leak test is performed to determine the leak.However, due to the components mixed in due to the leak, the outgas is insufficient, and a desired degree of vacuum is obtained. Labor and time are lost, for example, the baking has to be performed again. In order to solve this problem, as shown in the vacuum apparatus baking method of Patent Document 1, helium gas is introduced while replacing the atmosphere in a baking panel surrounding the apparatus with nitrogen for baking, and leakage during baking is reduced. Detected.

In addition, when phosphorus is used as a raw material in an MBE (Molecular Beam Epitaxy) apparatus or the like for producing a compound semiconductor, phosphorus other than the phosphorus that has flown onto a substrate is trapped and adsorbed on the inner wall surface of a vacuum chamber or a liquid nitrogen shroud. Some of the phosphorus forms a molecule and becomes white phosphorus (P ₄ ). Since white phosphorus is ignitable in the atmosphere, in order to periodically open the vacuum chamber for maintenance or to open to the atmosphere in the event of trouble, bake it at about 200 ° C before opening it, and spontaneously ignite white phosphorus by high-temperature treatment. It must be decomposed into red phosphorus (P ₂ ), which does not have any residue, and then released to the atmosphere.

  The decomposition process of white phosphorus cannot be measured by a conventional quadrupole mass spectrometer due to the problem of heat resistance because the chamber is in a high temperature state. Therefore, for the baking processing time at that time, the total pressure in the chamber is monitored with a vacuum gauge, and the stage at which the decomposition is completed is empirically determined.

JP-A-7-14766

  When the control unit including the ion source control circuit, the quadrupole electric field control circuit, and the ion current detection circuit is directly attached to the vacuum flange of the analysis tube via a connector such as a current introduction terminal, the electronic devices connected to the control unit In general, the temperature of the control unit should not be set to 100 ° C. or higher in order to protect low heat-resistant members such as components and boards. When the vacuum chamber to which the quadrupole mass spectrometer is connected is brought to a high temperature of about 200 ° C. by baking or the like, the temperature of the control unit becomes 100 ° C. or higher due to heat conduction from the connecting unit. It must be removed, which makes it impossible to analyze the residual gas in the vacuum chamber at high temperatures.

  In addition, when the setting of the baking temperature of the vacuum chamber is reduced to about 150 ° C. in order to suppress the temperature of the control unit to 100 ° C. or less, the baking efficiency is lower than that of the baking performed at 200 ° C. Requires a long baking time. In addition, when the vacuum chamber is baked at 200 ° C., the temperature of the control unit is controlled to 100 ° C. or less, and when the whole connected analytical tube is cooled, the gas released from the chamber during the baking is cooled. Since the components are repeatedly detected by adsorption and desorption on the inner surface of the cooled analysis tube, gas components in the original vacuum chamber cannot be measured, and accurate measurement during baking cannot be performed. Further, in this case, since the analysis tube is not baked, a desired ultimate degree of vacuum may not be obtained for the connected vacuum chamber due to the gas released from the analysis tube.

  When the control section is separated from the analysis tube and connected via a signal cable, the signal cable connection section has no heat resistance, so when the temperature rises due to baking, the signal cable must be removed. Gas analysis during baking is not possible. Further, in the vacuum apparatus baking method described in Patent Document 1, helium gas must be constantly introduced during baking, which is costly. Further, the atmosphere in the baking panel is used in combination with the atmosphere of nitrogen replacement. However, if the confidentiality of the panel is not sufficient, there is a risk that nitrogen gas leaks out and the surrounding workers are deprived of oxygen.

  An object of the present invention is to provide a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer capable of measuring without deteriorating sensitivity even under high temperature conditions, a baking method for the vacuum chamber with a gas analyzer, and gas analysis. It is an object of the present invention to provide a method for analyzing a residual gas in an instrumented vacuum chamber.

The present invention relates to a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer for performing gas analysis in a vacuum chamber,
The quadrupole mass spectrometer comprises:
An analysis tube having an ion source for ionizing existing gas, a quadrupole for identifying the type of ions, and a detection unit for detecting the amount of ions,
A control unit for controlling the analysis tube,
A sealed connection portion that seals an attachment port of the vacuum chamber into which the analysis tube is inserted, and connects the analysis tube and a control unit via a signal cable.
A cooling unit provided on the outer periphery of a joint between the mounting port and the sealed connection unit,
The said analysis tube is heated and the said junction part is cooled by the said cooling part, It is the vacuum chamber with a gas analyzer.

The present invention also provides a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer for performing gas analysis in a vacuum chamber,
The quadrupole mass spectrometer comprises:
An analysis tube having an ion source for ionizing existing gas, a quadrupole for identifying the type of ions, and a detection unit for detecting the amount of ions,
A control unit for controlling the analysis tube,
A tube having the analysis tube therein;
Sealing the open end of the open end of the tube opposite to the side connected to the vacuum chamber, and connecting the tube and the control unit via a signal cable;
A cooling unit provided on the outer periphery of the joint between the open end and the sealed connection unit,
The analysis tube is heated by heating the tube, and the joint is cooled, thereby providing a vacuum chamber with a gas analyzer.

  Further, the present invention is characterized in that there is a heater wire wound around the vacuum chamber and the tube to heat the vacuum chamber and the tube.

Further, the present invention includes a baking panel for heating around a vacuum chamber with a gas analyzer,
The cooling unit and the control unit are disposed outside a baking panel.

  The present invention also provides a gas chamber with a gas analyzer characterized in that at least the analysis tube and the vacuum chamber are heated by enclosing a portion of the vacuum chamber with a gas analyzer except for a cooling unit and a control unit with a baking panel. This is a method for baking a vacuum chamber.

  Further, the present invention provides a gas characterized by analyzing a residual gas in a vacuum chamber by a quadrupole mass spectrometer while heating at least an analysis tube and a vacuum chamber by the above-described baking method for a vacuum chamber with a gas analyzer. This is a method for analyzing residual gas in a vacuum chamber with an analyzer.

  According to the present invention, in a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer for performing gas analysis in a vacuum chamber, the quadrupole mass spectrometer is an ion source unit for ionizing an existing gas, It has an analysis tube having a quadrupole for identifying the type of ion and a detection unit for detecting the amount of ions, and a control unit for controlling the analysis tube.

  The sealing connection unit seals an attachment port of the vacuum chamber into which the analysis tube is inserted, and connects the analysis tube and the control unit via a signal cable. The cooling part provided on the outer periphery of the junction between the mounting port and the sealed connection part cools the junction, so that the analysis tube is heated during baking, but the signal cable and the control unit are not heated.

  Thus, the measurement can be performed without deteriorating the sensitivity even under a high temperature condition. In addition, according to the gas analysis result, it is possible to shorten a step involving a high-temperature treatment such as a baking step.

  Further, according to the present invention, in a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer for performing gas analysis in a vacuum chamber, the quadrupole mass spectrometer is an ion source unit for ionizing existing gas. , An analysis tube having a quadrupole for identifying the type of ions and a detection unit for detecting the amount of ions, and a control unit for controlling the analysis tube.

  The sealed connection portion seals the open end of the tube into which the analysis tube is inserted, opposite to the side connected to the vacuum chamber, and connects the analysis tube and the control unit via a signal cable. I do. The cooling unit provided on the outer periphery of the joint between the open end and the sealed connection cools the joint, so that the analysis tube is heated, but the signal cable and the control unit are not heated.

  Thus, the measurement can be performed without deteriorating the sensitivity even under a high temperature condition. In addition, according to the gas analysis result, it is possible to shorten a step involving a high-temperature treatment such as a baking step.

  Further, according to the present invention, the vacuum chamber and the tube into which the analysis tube is inserted can be easily heated by the heater wire wound around the tube into which the analysis tube is inserted.

  According to the invention, a baking panel is provided for heating the vacuum chamber with the gas analyzer, and the cooling unit and the control unit are arranged outside the baking panel.

  Thus, the inside of the baking panel can be uniformly heated without heating the signal cable and the control unit.

  Further, according to the present invention, at least the analysis tube and the vacuum chamber are heated by surrounding the portion of the vacuum chamber with the gas analyzer except for the cooling unit and the control unit with the baking panel.

  Thereby, the inside of the baking panel can be uniformly heated without heating the signal cable and the control unit, and the measurement can be performed without deteriorating the sensitivity even under a high temperature condition.

  According to the present invention, the residual gas in the vacuum chamber is analyzed by the quadrupole mass spectrometer while at least the analysis tube and the vacuum chamber are heated by the above-described baking method for the vacuum chamber with a gas analyzer.

  This makes it possible to measure the residual gas without deteriorating the sensitivity even under a high temperature condition, and it is possible to shorten the residual gas analysis step accompanying the high temperature treatment according to the gas analysis result.

  FIG. 1 is a diagram showing a configuration of a quadrupole mass spectrometer 10 provided in a vacuum chamber with a gas analyzer of the present invention described later with reference to FIG. The quadrupole mass spectrometer 10 includes an ion source unit 11, a quadrupole unit 12, a detection unit 13, a control unit 14, a cooling block 15, a signal cable 16, and a sealed connection unit 17 which constitute an analysis tube. The ion source section 11 is a section where electrons collide with gas present in the vacuum chamber 18 and are ionized. A part of the ionized gas moves to the quadrupole section 12. In the quadrupole section 12, four cylindrical rod electrodes arranged in parallel with each other are installed, and a superposed electric field of direct current and alternating current is applied to form a quadrupole field.

  When the gas ionized by the ion source unit 11 reaches the quadrupole unit 12, the ions receive a force due to the magnitude of the electric field applied by the four electrodes, and the force is applied along the axis of the four electrodes. Proceed while vibrating. Here, the ions that pass through the quadrupole section 12 and reach the detection section 13 are limited by the magnitude of the electric field applied to the quadrupole section 12 and are ions having a certain mass-to-charge M / e. Limited. M / e is also called a mass number and corresponds to the mass number of an ion. Ions having other mass numbers deviate from the axis while passing through the quadrupole section 12, and do not reach the detection section 13. Therefore, by changing the electric field applied to the quadrupole portion 12 and scanning, it is possible to identify ions having a specific mass number passing through the quadrupole portion 12.

  The detection unit 13 detects ions that have passed through the quadrupole unit 12 and outputs the ions as an ion current. As a detection method, measurement is performed using a Faraday cup as a collector. In order to further improve detection sensitivity, a secondary electron multiplier is provided. The control unit 14 is connected to the sealed connection unit 17 via a control signal cable 16 and includes an electronic circuit including a control circuit for performing the above-described ion source control, quadrupole field control, and detection in the detection unit. ing. The cooling block 15 serving as a cooling unit is in close contact with an outer peripheral portion of a joint portion between the flange of the vacuum chamber 18 serving as an attachment port and the sealed connection portion 17, and a cooling pipe (not shown) is provided inside. And a cooling medium is introduced. The cooling block 15 locally cools the joint. As a cooling medium, cooling water, liquid nitrogen, liquid helium, and a cooling gas (an inert gas such as air, nitrogen, and argon) can flow. The hermetically-sealed connection portion 17 is joined to a flange of the vacuum chamber 18 to seal the vacuum chamber, and a terminal for inputting a control signal sent from the control portion 14 through the signal cable 16 to the analysis tube, and detection from the analysis tube. A terminal for outputting a signal is provided.

  With the above configuration, even when a heater wire is wound around the vacuum chamber 18 to which the quadrupole mass spectrometer 10 is connected and high-temperature baking is performed at 200 ° C., the temperature of the sealed connection portion 17 is locally kept at 100 ° C. or lower. Therefore, measurement can be performed even under high temperature conditions.

  Although the cooling block 15 provided with a pipe through which a cooling medium flows as a cooling unit has been described, a cooling pipe may be directly wound around the joint, or the joint may be cooled by a fan.

  First, the sensitivity of the quadrupole mass spectrometer 10 to argon gas was measured. FIG. 2 is a diagram showing a configuration of an argon gas sensitivity measuring device including the quadrupole mass spectrometer 10. The measurement method is as follows: an analysis tube (ion source unit 11, quadrupole unit 12, and detection unit 13) is installed in a stainless steel tube 24, and a constant flow of argon gas is introduced while the inside of the stainless steel tube 24 is evacuated. Sensitivity was measured by measuring ionic current and degree of vacuum. The stainless steel tube 24 is provided with a vacuum exhaust port 25, a vacuum gauge mounting port 26, and an argon gas introduction port 27 separately, and a vacuum pump (not shown), a vacuum gauge (not shown), and a gas introduction system, respectively. (Not shown) is connected.

The control unit 14 is separated from the analysis tube via a signal cable 16, and a cooling block 15 provided with a cooling pipe therein is installed on the outer periphery of a joint between the sealed connection unit 17 and the vacuum flange. By flowing cooling water, the joint is locally cooled. A heater (not shown) for heating is wound around the stainless steel tube 24. The stainless steel tube 24 is baked and sufficiently degassed by the heater before the measurement, and the stainless steel tube 24 is heated to about 3 × 10 ⁻⁸ Pa. After reaching the degree of vacuum in the ultra-high vacuum region, measurement was performed by introducing argon gas.

FIG. 3 is a graph showing measurement results when an argon gas was introduced. FIG. 3A shows the result of measurement at room temperature, and FIG. 3B shows the result of measurement when the temperature of the stainless steel tube was raised to 200 ° C. The introduction amount of the argon gas was introduced by a vacuum gauge connected to the stainless steel tube 24 so that the degree of vacuum was constant at 5 × 10 ⁻⁴ Pa. Since the argon gas is a high-purity gas having an impurity concentration of 1 ppm or less, there is no problem even if the total pressure detected by the vacuum gauge is regarded as the argon partial pressure. The ion current value was measured by scanning in the range of M / e = 15 to M / e = 45 at both room temperature and 200 ° C. The peaks appearing at M / e = 20 and 40 are for the detection of argon ions, and the sum of the ion current values of both peaks is a value proportional to the argon partial pressure. Therefore, the sensitivity is obtained from the sum of the ion current values of both peaks and the ratio of the introduced argon gas pressure. When the sensitivity is obtained under both room temperature and 200 ° C. conditions, 1.2 × 10 ⁻² A / Pa is obtained. It has been found that the sensitivity of the quadrupole mass spectrometer 10 is not deteriorated by increasing the temperature of the measurement environment.

  Next, the chamber temperature dependence of the output signal level (ion current) obtained when the vacuum chamber to which the quadrupole mass spectrometer 10 was attached was baked was measured. In the baking method, the ion source, the quadrupole section and the detection section of the quadrupole mass spectrometer 10 are housed as in the configuration of the vacuum chamber with a gas analyzer according to the embodiment of the present invention shown in FIG. The entirety of the vacuum chamber 18 to which the stainless steel analysis tube 41 was attached was surrounded by a baking panel 46. Thereby, all the members in the baking panel 46 are uniformly baked.

The control unit 14 of the quadrupole mass spectrometer 10 is connected to the vacuum flange by a sealed connection 17 via a signal cable 16. An aluminum block 44 for cooling is provided at a joint between the sealed connection portion 17 and the vacuum flange, and cooling water flows inside to cool the joint locally. At this time, baking is performed in such a configuration that only the water-cooled joint flange of the analysis tube 41 of the quadrupole mass spectrometer 10 comes out of the panel. The measurement was performed as follows. The vacuum chamber 18 used for the measurement is sufficiently degassed by performing baking before the main measurement, and maintains an ultrahigh vacuum region of 5 × 10 ⁻⁹ Pa as the degree of vacuum. At this time, the residual gas existing in the vacuum chamber 18 was in a state where hydrogen was the main component.

  FIG. 5 is a graph showing changes over time in the ion current of helium (He), the degree of vacuum, and the temperature of the vacuum chamber during baking. A constant amount of He gas was introduced into the vacuum chamber 18 to which the quadrupole mass spectrometer 10 was attached, and the change over time in the ion current when the temperature of the vacuum chamber 18 was raised from room temperature to 200 ° C. was measured. The mass number of He ions is M / e = 4. Further, as a background signal level, a temporal change of M / e = 7, which is an ion species that cannot normally exist, is also measured. Further, the degree of vacuum and the temperature of the vacuum chamber at this time are also measured at the same time.

At the start of the measurement, the degree of vacuum in the vacuum chamber 18 is 5 × 10 ⁻⁹ Pa, and He gas is introduced into the vacuum chamber to increase the pressure to 3 × 10 ⁻⁵ Pa. The chamber temperature is raised from room temperature to 200 ° C. while He gas is constantly introduced so as to keep this pressure constant. At this time, the temperature of the analysis tube 41 of the quadrupole mass spectrometer 10 becomes the same as that of the vacuum chamber 18. When He gas is introduced when the vacuum chamber 18 is at room temperature, the ion current value of He is about 1.5 × 10 ⁻⁸ A, and even if the vacuum chamber is heated to 200 ° C., the ion current value remains in the process. There is no big change.

In addition, the ion current value of M / e = 7 measured as the background level was 1.5 × 10 ⁻¹³ A, which was almost constant and no large change was observed. Therefore, it is found that the detection signal level is not deteriorated or the ground level is not extremely increased due to the rise in the temperature of the analysis tube 41. As a result, it was found that the analysis of the residual gas in the vacuum chamber 18 under the high temperature condition can be performed without deteriorating the sensitivity.

Next, using a quadrupole mass spectrometer 10, the change with time of the residual gas in the baking step of the vacuum chamber was measured. The vacuum chamber was in a state after being opened to the atmosphere for periodic maintenance, and the measurement was started one hour after evacuation was started. FIG. 6 is a graph showing a temporal change of the ion current of a typical residual gas during baking. Curve a is hydrogen (H ₂ ) at M / e = 2, curve b is hydrocarbon (CH ₄ ) at M / e = 16, curve c is water (H ₂ O) at M / e = 18, and curve d is M / e = 14 and nitrogen (N ₂ ) or carbon monoxide (CO), curve e is M / e = 32 and oxygen (O ₂ ), curve f is M / e = 40 and argon (Ar). Corresponds to the aging of the species.

In the figure, baking was started at point A, and baking was completed at point B. Before the start of baking, the most residual gas species present in the vacuum chamber is M / e = 18 (moisture), which once increases after the start of baking, reaches a local maximum at a certain point, and then gradually decreases. I have. After the completion of baking, the value sharply decreased, and was approximately constant at a value of 1.5 × 10 ⁻¹¹ A about 10 hours after baking. After baking, it has been confirmed that the degree of vacuum in the vacuum chamber has reached an ultra-high vacuum of 5 × 10 ⁻⁹ Pa, and M / e = 2 (hydrogen) as a main component as a residual gas species. I have. Such a tendency of the change of M / e = 18 (moisture) is the same for other gas species, but the baking step after opening to the atmosphere removes moisture existing as a main component in the initial stage of the exhaust process. By doing this, it was clarified by this measurement that this was a step of obtaining a high vacuum.

FIG. 7 is a graph showing changes over time in the ion current value and the degree of vacuum at M / e = 18 (moisture) before and after baking. FIG. 7A shows the degree of vacuum, and FIG. 7B shows the change over time in the ion current. Curves A1 and A2 show the case where the baking time is 24 hours, curves B1 and B2 show the case where the baking time is 38 hours, and curves C1 and C2 show the case where the baking time is 48 hours. Looking at A2, B2 and C2, the change with time of the moisture reaches a local maximum immediately after the start of baking, and gradually decreases. After the baking is completed, the value rapidly decreases, and after a certain period of time, each ion current value gradually approaches a certain value. This tendency is the same as the measurement result of FIG. 6, but it can be seen that the ultimate degree of vacuum after the completion of baking differs depending on the baking time. That is, when the baking time is 24 hours (curves A1 and A2), the moisture level decreases from the maximum value to about 3.5 × 10 ⁻⁹ A during baking, and the ultimate vacuum degree after baking is 2 × 10 ^{−10. 8} Pa was obtained.

On the other hand, when the baking time was 38 hours (curves B1 and B2), the moisture level decreased from the maximum value to 1.3 × 10 ⁻⁹ A, and the ultimate vacuum after baking was 4 × 10 ⁻⁹ Pa. . When the baking time is 48 hours (curves C1 and C2), the moisture level decreases from the maximum value to 1.2 × 10 ⁻⁹ A, and the ultimate vacuum after baking is 4.5 × 10 ⁻⁹ Pa. became. The curves B1 and C1 have different baking times, but there is no great difference in the moisture level at the end of baking, and the ultimate vacuum degree is almost the same. Therefore, if the moisture level drops to a certain level during baking, It was found that the same degree of vacuum in the ultra-high vacuum region could be obtained. Therefore, by successively monitoring the moisture level during baking, it is possible to determine the end of baking when the moisture level falls below a certain level, so that the baking time can be reduced. Conversely, from the results of A1 and A2, if the baking is terminated at a time point when the moisture level immediately before the end of the baking is higher than a certain level, the target ultimate vacuum degree will not be reached.

  From the above results, it is possible to determine whether or not baking has been sufficiently performed by measuring the level of residual moisture in the vacuum chamber during baking with a quadrupole mass spectrometer, and to shorten the baking time. be able to.

  FIG. 8 is a graph showing the change over time in the ion current and the degree of vacuum of typical residual gas components during baking of the vacuum chamber. At the point A in the figure, the ion current values of M / e = 14, 32 and 40 sharply increase, and this is because at this point, a micro leak occurs at any point in the vacuum chamber for some reason, It indicates that the air flowed into the inside.

  Looking at the change in the degree of vacuum at this time, it is difficult to determine whether or not a leak has occurred from the change in the degree of vacuum because the change has not been extremely extreme. Therefore, in the past, a minute leak during baking, which could only be confirmed after completion of baking, can be confirmed during baking by using the vacuum chamber with a gas analyzer of the present invention. As a result, it is possible to deal with a leak trouble at the time of occurrence, and it is possible to stop baking and to improve the efficiency of work. In addition, a leak check during baking, which was impossible in the past, can be performed at any time by using the quadrupole mass spectrometer of the present invention.

In addition, the measurement was performed for the phosphorus treatment step when the quadrupole mass spectrometer was attached to the growth chamber of the MBE apparatus. FIG. 9 is a graph showing the change over time of the ion current of white phosphorus existing in the growth chamber during baking. The analysis gas type is P ₄ (white phosphorus) having M / e = 124. Since white phosphorus may ignite when it comes into contact with the atmosphere, when opening the vacuum chamber, which is a growth chamber, to the atmosphere, it is necessary to bake the vacuum chamber in advance and heat it to about 200 ° C to decompose the white phosphorus. There is. Immediately after the start of baking, a large amount of release and decomposition of white phosphorus occurred, the degree of vacuum deteriorated extremely, and the pressure was out of the measurement pressure range of the quadrupole mass spectrometer. The measurement was started at the time.

As can be seen from the graph, the ion current value of P ₄ immediately after the start of the measurement shows a high value of 10 ⁻⁶ A or more, and asymptotically approaches a value of about 1 × 10 ⁻⁸ A as time passes. It was found to change slowly. Conventionally, since it was impossible to residual gas analysis in the vacuum chamber during baking, while monitoring the vacuum degree by the vacuum gauge (total pressure gauge), the decomposition of P ₄ is completed when it becomes higher to some extent the degree of vacuum They generally decided that they depended on experience. In addition, baking took a long time because of the danger. For example, it was determined that the phosphorus treatment was completed 100 hours after the start of baking, and the vacuum chamber, which was the growth chamber, was opened to the atmosphere. However, from the measurement results in FIG. 9, 80 hours after the start of baking, the current value level of P ₄ has been reduced to substantially the same level as that of P ₄ after 100 hours, and at this stage, the vacuum chamber can be opened to the atmosphere. Can be determined. In this case, it is understood that the process can be shortened by at least about 20 hours. Also, so far it is possible to quantitatively determine the degradation completion stage of P ₄ which has been determined only by the degree of vacuum in the ion current value of P _4, is also useful in process control. From the above results, it became possible to quantify the phosphorus treatment step and to shorten the treatment time.

The present invention is capable of the following embodiments.
(1) An analysis tube inserted into a mounting port of a vacuum chamber for detecting ions, a control unit for controlling the analysis tube is connected, and a sealed connection section for closing the mounting port and adjusting a temperature of the sealed connection section. A quadrupole mass spectrometer, comprising:

  A control unit for controlling the analysis tube is connected, and there is a temperature adjustment unit for adjusting the temperature of the sealed connection portion that seals the mounting port of the analysis tube, so that measurement can be performed without deteriorating sensitivity even under high temperature conditions. . In addition, this makes it possible to shorten a step involving a high-temperature treatment such as a baking step.

(2) The quadrupole mass spectrometer, wherein the temperature control unit includes a pipe through which a fluid flows.
Since the temperature control section includes a pipe through which the fluid flows, the sealed connection section can be cooled by flowing the cooling medium.

  (3) The quadrupole mass spectrometer, wherein the temperature control section is provided with a pipe for flowing a fluid around the outer periphery of the hermetically-sealed connection section.

  Since the pipe for flowing the fluid is provided on the outer peripheral portion of the sealed connection portion, the sealed connection portion can be locally cooled.

(4) The quadrupole mass spectrometer, wherein the temperature control section cools the sealed connection section using a fan.
The fan can be used to cool the sealed connection.

FIG. 2 is a diagram illustrating a configuration of a quadrupole mass spectrometer 10. FIG. 2 is a diagram showing a configuration of an argon gas sensitivity measurement device including a quadrupole mass spectrometer 10. It is a graph which shows the measurement result of the ion current at the time of introducing argon gas. FIG. 1 is a diagram showing a configuration of a vacuum chamber with a gas analyzer according to one embodiment of the present invention. 6 is a graph showing changes with time in ion current, degree of vacuum, and vacuum chamber temperature when helium gas is introduced during baking. 6 is a graph showing a temporal change of an ion current of a typical residual gas during baking. It is a graph which shows the ion current value of water before and after baking, and the time-dependent change of the degree of vacuum. 5 is a graph showing changes with time in ion current and degree of vacuum of residual gas components during baking of a vacuum chamber. 5 is a graph showing a change over time of an ion current of white phosphorus present in a growth chamber during baking.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 10 Quadrupole mass spectrometer 11 Ion source part 12 Quadrupole part 13 Detection part 14 Control part 15 Cooling block 16 Signal cable 17 Sealing connection part 18 Vacuum chamber 24 Stainless steel tube 25 Vacuum exhaust port 26 Vacuum gauge attachment part 27 Argon gas Introduction port 41 Analysis tube 44 Aluminum block for cooling 46 Baking panel

Claims (6)

In a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer for performing gas analysis in a vacuum chamber,
The quadrupole mass spectrometer comprises:
An analysis tube having an ion source for ionizing existing gas, a quadrupole for identifying the type of ions, and a detection unit for detecting the amount of ions,
A control unit for controlling the analysis tube,
A sealed connection portion that seals an attachment port of the vacuum chamber into which the analysis tube is inserted, and connects the analysis tube and a control unit via a signal cable.
A cooling unit provided on the outer periphery of a joint between the mounting port and the sealed connection unit,
The said analysis tube is heated and the said junction part is cooled by the said cooling part, The vacuum chamber with a gas analyzer characterized by the above-mentioned. In a vacuum chamber with a gas analyzer equipped with a quadrupole mass spectrometer for performing gas analysis in a vacuum chamber,
The quadrupole mass spectrometer comprises:
An analysis tube having an ion source for ionizing existing gas, a quadrupole for identifying the type of ions, and a detection unit for detecting the amount of ions,
A control unit for controlling the analysis tube,
A tube having the analysis tube therein;
Sealing the open end of the open end of the tube opposite to the side connected to the vacuum chamber, and connecting the tube and the control unit via a signal cable;
A cooling unit provided on the outer periphery of the joint between the open end and the sealed connection unit,
A vacuum chamber with a gas analyzer, wherein the analysis tube is heated by heating the tube, and the joint is cooled.   The vacuum chamber with a gas analyzer according to claim 2, further comprising a heater wire wound around the vacuum chamber and the tube to heat the vacuum chamber and the tube. A baking panel for heating around a vacuum chamber with a gas analyzer is provided,
The vacuum chamber with a gas analyzer according to any one of claims 1 to 3, wherein the cooling unit and the control unit are arranged outside a baking panel.   3. A vacuum chamber with a gas analyzer according to claim 1, wherein at least the analysis tube and the vacuum chamber are heated by surrounding a portion except for a cooling unit and a control unit with a baking panel. Baking method of vacuum chamber.   A gas analyzer characterized by analyzing a residual gas in a vacuum chamber by a quadrupole mass spectrometer while heating at least an analysis tube and the vacuum chamber by the method for baking a vacuum chamber with a gas analyzer according to claim 5. Method for analyzing residual gas in a vacuum chamber equipped with

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