JP2020020586A - Gas analyzer and gas analysis method - Google Patents

Abstract

To be able to analyze residual gas with high-sensitivity, regardless of whether the amount of the residual gas in a specimen is large or small.SOLUTION: There are provided: a sample chamber 1 for extracting residual gas from a specimen 3 in vacuum; an intermediate chamber 4 connected to the sample chamber 1 via a first vacuum valve in vacuum; a first analytical chamber 6 connected to the intermediate chamber 4 via a second vacuum valve in the vacuum state; a second analysis chamber 7 connected to the intermediate chamber 4 via an orifice 5 in the vacuum state; a vacuum gauge for measuring gas volume in the sample chamber 1; an exhaust section 8 for exhausting residual gas from the second analysis chamber 7; a control operation unit 9 that closes the second vacuum valve when the gas amount is equal to or more than a threshold value and opens the second vacuum valve when the gas amount is less than the threshold value; and one or more mass spectrometers to analyze the residual gas taken into the second analysis chamber 7 when the gas amount is equal or more than the threshold value, or to analyze the residual gas taken into the first analysis chamber 6 when the gas amount is less than the threshold value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas analyzer and a gas analysis method.

  Regarding the residual gas of a test sample such as a hermetically sealed semiconductor package and a hermetically sealed hollow semiconductor package such as a lamp, a composition analysis using a mass spectrometer in a vacuum is common. The amount of residual gas in the specimen changes due to leakage of residual gas in the sealing structure of the specimen and degassing from the material used. Therefore, the amount of residual gas in the test sample is not known until the sealing structure is broken and opened.

  Further, when a large amount of gas flows into the analysis chamber equipped with the mass spectrometer at one time, the operating pressure exceeds the upper limit, so that the composition of the residual gas cannot be analyzed if the amount of the residual gas is large. Also, if the amount of residual gas is too large, the mass spectrometer may fail.

  In order to cope with such a large amount of residual gas, when taking in the residual gas into the analysis chamber, it is conceivable to provide an orifice at the entrance of the analysis chamber to reduce the amount of the residual gas entering the analysis chamber. Since the residual gas flows into the analysis chamber one after another through the orifice, the residual gas is exhausted from the analysis chamber by the exhaust unit in a timely manner. The amount of residual gas staying in the analysis chamber can be controlled by the orifice and the exhaust.

  For example, Patent Literature 1 discloses a technique in which an orifice is provided between a sample chamber and an analysis chamber to analyze a residual gas flowing into an analysis chamber having a mass spectrometer.

JP 2008-180581 A

  As described above, the amount of the residual gas staying in the analysis chamber can be controlled by the orifice and the exhaust unit, but when the amount of the residual gas is small, the amount of the residual gas reaching the mass spectrometer by the orifice is reduced by the mass. The gas is narrowed down from the lower limit of detection by the analyzer, or a trace amount of residual gas reaching the analysis chamber is exhausted by the exhaust unit before being analyzed by the mass spectrometer.

  Therefore, when the amount of the residual gas is small, the composition cannot be analyzed, or the analysis efficiency decreases. On the other hand, unless an orifice or an exhaust portion is provided, it is impossible to cope with a large amount of residual gas as described above. An object of the present invention is to enable analysis of a residual gas with high sensitivity regardless of whether the amount of the residual gas in a test sample is large or small.

  In order to solve the above-described problems, the present invention provides a sample chamber for extracting a residual gas from a specimen in a vacuum, a sample chamber in a vacuum, and a method for capturing the residual gas from the sample chamber via a first vacuum valve. An intermediate chamber that is connected as possible, an intermediate chamber in a vacuum state, a first analysis chamber that is connected to be able to take in residual gas from the intermediate chamber via a second vacuum valve, and an intermediate chamber in a vacuum state. A second analysis chamber connected to be able to take in residual gas from the intermediate chamber via an orifice, a vacuum gauge for measuring the amount of residual gas in the sample chamber, and exhausting residual gas from the second analysis chamber. Exhaust unit to close the second vacuum valve when the gas amount is greater than or equal to the threshold, and open the second vacuum valve when the gas amount is less than the threshold, the vacuum gauge measured the gas amount of the residual gas A control operation unit that opens the first vacuum valve later and a gas amount In the above case, one or more mass spectrometers for analyzing the residual gas taken into the second analysis chamber and analyzing the residual gas taken into the first analysis chamber when the gas amount is less than the threshold value And a meter.

According to the present invention, it is possible to analyze the residual gas regardless of whether the amount of the residual gas in the specimen is large or small.

FIG. 2 is a schematic diagram illustrating one of the configurations of the gas analyzer according to Embodiment 1 of the present invention. FIG. 3 is a schematic diagram illustrating a configuration of a control calculation unit. 3 is a flowchart illustrating a gas analysis method using the gas analyzer according to Embodiment 1 of the present invention. 5 is a graph illustrating an example of a relationship between a pressure of a sample chamber of the gas analyzer and a pressure of a first analysis chamber immediately after opening a vacuum valve in the first embodiment of the present invention. 5 is a graph showing an example of a temporal change in pressure in the first analysis chamber before and after opening and closing of a vacuum valve when performing gas analysis in the first analysis chamber in the gas analyzer according to Embodiment 1 of the present invention. 5 is a graph showing an example of a temporal change in pressure in the second analysis chamber before and after opening and closing of a vacuum valve when performing gas analysis in the second analysis chamber in the gas analyzer according to Embodiment 1 of the present invention. It is a schematic diagram showing a configuration of a gas analyzer according to a second embodiment of the present invention. 9 is a flowchart illustrating a gas analysis method using the gas analyzer according to the second embodiment of the present invention. It is a schematic diagram showing a configuration of a gas analyzer according to a third embodiment of the present invention. FIG. 9 is a schematic diagram showing a configuration of a variable orifice used in a gas analyzer according to a third embodiment of the present invention. 9 is a flowchart illustrating a gas analysis method using the gas analyzer according to the third embodiment of the present invention. Dependence of the orifice numerical aperture of the variable orifice on the time change of the pressure in the first analysis chamber before and after opening and closing the vacuum valve when performing gas analysis in the first analysis chamber of the gas analyzer according to the third embodiment of the present invention. It is a graph which shows an example of sex. Dependence of the orifice opening number of the variable orifice on the time change of the pressure in the first analysis chamber before and after opening and closing the vacuum valve when performing gas analysis in the second analysis chamber of the gas analyzer according to the third embodiment of the present invention. It is a graph which shows an example of sex.

  Hereinafter, a gas analyzer according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited by the embodiment.

Embodiment 1 FIG.
The gas analyzer 100 according to the present invention analyzes the composition of the residual gas sealed in the sample. The drawings used in the description are not schematic diagrams showing actual dimensions and ratios of the present invention, but are schematic diagrams for explaining the present invention.

  FIG. 1 is a schematic diagram showing a configuration of a gas analyzer 100 according to Embodiment 1 of the present invention. As illustrated in FIG. 1, the gas analyzer 100 according to the present embodiment mainly includes a sample chamber 1, a first analysis chamber 6 and a second analysis chamber 7, an intermediate chamber 4, an orifice 5, an exhaust unit 8, It is composed of a calculation unit 9. Details of the configuration will be described below.

  The sample chamber 1 includes an unsealing device 2 for opening the test piece 3 placed in the sample chamber 1, a vacuum gauge G0, and a vacuum valve VV1. The sample chamber 1 is connected to the intermediate chamber 4 via a vacuum valve VV1. Examples of the vacuum gauges G0, G1, G2 include a spinning rotor gauge, a diaphragm vacuum gauge, and a crystal gauge.

  Further, as the vacuum gauges G0, G1, and G2, for example, an ionization vacuum gauge such as a cold cathode gauge or a BA (Bayard-Alpert) gauge, or a combination gauge combining an ionization vacuum gauge such as a crystal gauge and a cold cathode gauge is used. is there. The vacuum gauges G0, G1, and G2 measure pressure.

  The vacuum gauge G0 measures the pressure in the sample chamber 1. As the vacuum valve VV1, for example, a gate valve is used. The vacuum valve VV1 shuts off and opens the space between the sample chamber 1 and the intermediate chamber 4 by opening and closing the valve.

Here, the test body 3 has a hollow structure, and a very small semiconductor device having a volume within the hollow structure of less than 5 mm ³ or a so-called MEMS (Micro Electro Mechanical Systems) is assumed. The unsealing of the test piece 3 means that the residual gas of the test piece 3 is released into the sample chamber 1 by breaking the test piece 3.

  The intermediate chamber 4 includes a vacuum valve VV1, a vacuum valve VV2, and an orifice 5, and is connected to be able to take in residual gas from the sample chamber 1 via the vacuum valve VV1. The intermediate chamber 4 is connected to a first analysis chamber 6 via a vacuum valve VV2 and to a second analysis chamber 7 via an orifice 5. The orifice 5 has a function of restricting the flow of the residual gas. As the orifice 5, for example, a metal plate having a small hole and a cylindrical shape is used. As the vacuum valve VV2, for example, a gate valve is used.

  The vacuum valve VV2 is a vacuum valve that shuts off and opens the space of the first analysis chamber 6 and the intermediate chamber 4 by opening and closing the valve. When the control operation unit 9 opens the vacuum valve, the size of the vacuum valve becomes intermediate. It is desirable that the room 4 and the first analysis room 6 have a size that can be regarded as one large room.

  The first analysis chamber 6 includes a vacuum gauge G1 and a mass spectrometer MS1. The first analysis chamber 6 is connected to the intermediate chamber 4 so that residual gas from the intermediate chamber 4 can be taken in by the vacuum valve VV2. The vacuum gauge G1 measures the pressure in the first analysis chamber 6. As the vacuum gauge G1, for example, an ionization vacuum gauge such as a cold cathode gauge, a BA gauge, and a nude gauge is used.

  The residual gas released from the inside of the test body 3 passes through the vacuum valve VV1 and the intermediate chamber 4, and proceeds to the first analysis chamber 6 through the vacuum valve VV2. Then, the mass spectrometer MS1 measures and analyzes the residual gas taken into the first analysis chamber 6.

  As the mass spectrometers MS1 and MS2, for example, quadrupole mass spectrometers are used. Here, the mass spectrometers MS1 and MS2 have a predetermined upper limit pressure in use, and are assumed to be unsuitable for measuring and analyzing a large amount of gas. The mass spectrometers MS1 and MS2 may fail when a large amount of gas causes a large pressure in the atmosphere.

  Further, in the present embodiment, the mass spectrometers are the mass spectrometer MS1 in the first analysis chamber 6 and the mass spectrometer MS2 in the second analysis chamber 7, but are not limited to these numbers. is not. One mass spectrometer may measure and analyze the residual gas taken into the first analysis chamber and the residual gas taken into the second analysis chamber. The position where the mass spectrometer is installed is not limited as long as the residual gas taken into the first analysis chamber and the residual gas taken into the second analysis chamber can be measured and analyzed.

  In the second analysis chamber 7, a vacuum gauge G2, a mass spectrometer MS2, and an exhaust unit 8 are connected. The second analysis chamber 7 is connected to the intermediate chamber 4 so that residual gas from the intermediate chamber 4 can be taken in by the orifice 5. The vacuum gauge G2 measures the pressure in the second analysis chamber 7. An ionization vacuum gauge such as a BA gauge or a nude gauge is used as the vacuum gauge G2.

  The vacuum gauge G2 only needs to be able to measure pressure, and may be of the same type as or different from the vacuum gauges G0 and G1. In the present embodiment, the pressure of the residual gas is measured, but it is sufficient that the gas amount can be measured. The mass spectrometer MS2 measures and analyzes the residual gas released from the inside of the specimen 3 through the vacuum valve VV1 and the intermediate chamber 4 and introduced into the second analysis chamber 7 through the orifice 5. is set up.

  The orifice 5 can reduce the amount of residual gas that moves from the intermediate chamber 4 to the second analysis chamber 7. If the conductance of the orifice 5 is too small, the amount of gas that moves to the second analysis chamber 7 through the orifice 5 becomes small and exceeds the lower limit of measurement. Therefore, it is preferable that the conductance of the orifice 5 is not too small.

  As the mass spectrometer MS2, for example, a quadrupole mass spectrometer is used like the mass spectrometer MS1. Here, it is assumed that the mass spectrometer MS1 and the mass spectrometer MS2 have the same performance, but the present invention is not limited to this, and any device that measures and analyzes the composition of the residual gas can be used. Well, there may be differences in performance.

  An exhaust unit 8 is connected to the second analysis chamber 7. As the exhaust unit 8, a turbo-molecular pump using a rotary pump as the auxiliary pump, for example, configured by a main exhaust unit and an auxiliary pump is used. In addition, the exhaust unit 8 may use not only a turbo molecular pump but also an exhaust unit 8 using an NEG (Non Evaporated Getter) pump or an ion pump.

  By the exhaust unit 8, the residual gas flowing from the sample chamber 1 into the second analysis chamber 7 through the orifice 5 is exhausted from the second analysis chamber 7. By combining the exhaust unit 8 and the orifice 5, the flow rate of the residual gas exhausted from the sample chamber 1 and the intermediate chamber 4 can be controlled. Before starting the test, all the vacuum valves of the gas analyzer 100 are opened and evacuated, so that the sample chamber 1, the intermediate chamber 4, the first analysis chamber 6, and the second analysis chamber 7 can be evacuated. The vacuum here means a vacuum based on the definition of JIS.

  The mass spectrometer MS1 and the mass spectrometer MS2 used in each of the first analysis chamber 6 and the second analysis chamber 7 include a function for controlling the operation of the mass spectrometer and an operation for processing the obtained data. A control operation unit 9 having a function is connected. As the detectors of the mass spectrometers MS1 and MS2, for example, a Faraday cup or a secondary electron multiplier is used. The upper limit of the measurable analysis chamber pressure in the Faraday cup is about 0.01 Pa to 0.001 Pa. The upper limit of the pressure in the analysis chamber that can be measured by the secondary electron multiplier is about 0.001 Pa to 0.0001 Pa.

  A typical example of a mass spectrometer is a quadrupole mass spectrometer.However, when measuring multiple mass-to-charge ratios, the measurement cycle takes substantially several seconds, so the time required for residual gas to escape from the analysis chamber is measured. When the period is shorter than the period, the mass spectrometer cannot measure the mass-to-charge ratio.

  In the mass spectrometer MS1, the residual gas of interest needs to be measured at least once before the residual gas is exhausted from the first analysis chamber 6. If the residual gas is very small when the test piece 3 is opened, it is desirable to lengthen the residence time of the residual gas in the first analysis chamber 6. According to the configuration of the first embodiment, in the first analysis chamber 6, the amount of residual gas exhausted from the first analysis chamber 6 through the orifice 5 can be reduced. As described above, the upper limit pressure of the mass spectrometers MS1 and MS2 is determined in use.

  In addition, the vacuum gauges G0, G1, G2, the mass spectrometers MS1, MS2, and the vacuum valves VV1, VV2 of the gas analyzer 100 are electrically connected to each other by a control operation unit 9 and a communication path 10, respectively. I have. The control calculation unit 9 records and calculates the measurement data obtained by the vacuum gauges G0, G1, G2 and the mass spectrometers MS1, MS2, and controls the opening and closing operations of the vacuum valves VV1, VV2. I do.

  FIG. 2 is a schematic diagram illustrating a configuration of the control calculation unit 9. The control calculation unit 9 includes a reception unit that receives measurement data from the vacuum gauges G0, G1, and G2 and the mass spectrometers M1 and M2, a storage unit that stores the received measurement data, a calculation unit that calculates the measurement data, It has a determination unit for determining whether the vacuum valves VV1 and VV2 are opened and closed, and a transmission unit for transmitting an open / close command for operating the vacuum valves VV1 and VV2 to the vacuum valves VV1 and VV2.

  The processing of the calculation unit and the determination unit is realized by a calculation device 202 such as a CPU, and the storage unit is realized by a storage device 203 such as a memory, an HDD, and an SSD. The receiving unit is realized by the input interface (IF) 201, and the transmitting unit is realized by the output interface (IF) 204. The control operation unit 9 is connected to vacuum gauges G0, G1, G2, mass spectrometers MS1, MS2, vacuum valves VV1, VV2, and the like via a communication path 10.

  FIG. 3 is a flowchart showing a gas analysis method using the gas analyzer 100. The procedure for analyzing the residual gas in the test piece 3 will be described with reference to the flowchart in FIG. According to the first embodiment, whether the partial pressure is measured in the first analysis chamber 6 or the second analysis chamber 7 depends on the value of the pressure in the sample chamber 1 when the test piece 3 is opened ( Select according to the vacuum gauge G0). This allows analysis of residual gas inside the hermetic sealing device corresponding to a wider pressure range.

  First, the sample chamber 1 is opened to the atmosphere, and the specimen 3 which is a hermetically sealed device is set in the sample chamber 1 (step S101). All the chambers (the sample chamber 1, the intermediate chamber 4, the first analysis chamber 6, and the second analysis chamber 7) in the apparatus are all opened to the atmosphere, the exhaust unit 8 is stopped, and the vacuum valves VV1 and VV2 are turned off. The opened state is the initial state. In an initial state, the test body 3 is set inside the sample chamber 1. In this embodiment, all the rooms are open to the atmosphere. However, the present invention is not limited to this. When the test specimen 3 is installed, at least the sample chamber 1 only needs to be open to the atmosphere.

  After the test body 3 is installed, the exhaust unit 8 is started in a state where all the vacuum valves VV1 and VV2 of the gas analyzer 100 are opened, and all the rooms (the sample room 1, the intermediate room 4, the first analysis room 6, The evacuation of the second analysis chamber 7) is started (step S102). All the rooms (the sample chamber 1, the intermediate chamber 4, the first analysis chamber 6, and the second analysis chamber 7) in the apparatus are exhausted by using the exhaust unit 8. Here, exhaust is sufficiently performed until the background pressure in all the rooms (the sample chamber 1, the intermediate chamber 4, the first analysis chamber 6, and the second analysis chamber 7) is stabilized (Step S103).

  When the evacuation of all the rooms (the sample room 1, the intermediate room 4, the first analysis room 6, and the second analysis room 7) is completed, the vacuum valve VV1 is closed to isolate the sample room 1 and the intermediate room 4 ( Step S104). The sealing structure of the test piece 3 is broken and opened using the opening device 2 (step S105). The residual gas sealed in the test body 3 spreads to the sample chamber 1 instantaneously. The pressure of the spread residual gas is measured by a vacuum gauge G0.

Here, the volume inside the sample chamber 1 is V ₀ , the pressure inside the sample chamber 1 before opening the specimen 3 is p ₀ , and the pressure immediately after opening the specimen 3 measured by the vacuum gauge G0 is P _0. Then, the gas amount Q of the residual gas sealed inside the test body 3 can be expressed as Q = V ₀ × (P ₀ −p ₀ ).

The approximate _value of p ₀ can be estimated by the build-up method. For example, in the gas analyzer 100 after evacuation before the sealing structure of the test piece 3 is broken, the value of the vacuum gauge G0 when the vacuum valve VV1 is closed, that is, the pressure of the sample chamber 1 without residual gas. Is obtained as the background pressure p ₀ .

At this time, _assuming that the volume of the specimen 3 is V _s and the pressure of the residual gas of the specimen 3 is P _s , the pressure of the residual gas of the specimen 3 is obtained from the pressure P ₀ of the sample chamber 1 when the specimen 3 is opened. P _s = (V ₀ / V _s ) × P ₀ That is, the pressure P ₀ of the sample chamber 1, the pressure P _s of the gas amount Q and the residual gas in the residual gas can be known.

The choice of measuring the residual gas in the first analysis chamber 6 or the second analysis chamber 7 is made based on the gas amount Q of the residual gas. Here, the gas amount is Q, but the present invention is not limited to this. The analysis chamber may be selected based on the pressure of the residual gas as in the present embodiment, and there is no limitation. Pressure _{P 0} of the sample chamber 1 is background pressure _{p 0} of the sample chamber 1 is sufficiently small compared to _{P 0 (P} 0 >> _{p 0) case,} treated as _(P 0 -p ₀₎ ≒ _{P 0} When the volume V ₀ of the sample chamber 1 is a constant, the gas amount Q of the residual gas is uniquely determined by the pressure P ₀ of the sample chamber 1, so that the first analysis chamber 6 and the second analysis chamber are determined by the pressure P ₀ . The selection of the room 7 may be performed.

In the gas analyzer 100 of the present invention, the residual gas is analyzed in the first analysis chamber 6 based on the value of the pressure P ₀ of the sample chamber 1 when the test piece 3 is opened, or in the second analysis chamber. It is determined whether to use the second analysis room 7 (step S106). Hereinafter, in the switching determination analysis chamber, illustrating the flow determination method based on the measurement value of the gas quantity Q rather than a vacuum gauge G0 (pressure P ₀ of the sample chamber _1). Incidentally, in the apparatus of the present invention, the volume of the beginning Other room volume V ₀ which the sample chamber 1 is a constant.

The value of the vacuum gauge G0 measured in the sample chamber 1 is transmitted to the control calculation unit 9. The control operation unit 9 controls opening and closing of the vacuum valve VV2 based on the received value of the vacuum gauge G0. The value of the vacuum gauge G0, that is, when the pressure P ₀ of the sample chamber 1 is the threshold value P ₀ ^* above, the control arithmetic unit 9 closes the vacuum valve VV2 located between the first analysis chamber 6 and the intermediate chamber 4 (Step S107), the first analysis chamber 6 is isolated from the intermediate chamber 4. Then, the control calculation unit 9 opens the vacuum valve VV1 between the sample chamber 1 and the intermediate chamber 4 (Step S108), and the mass spectrometer MS2 in the second analysis chamber 7 has the residual mass sealed in the test specimen 3. The gas is measured and analyzed (step S109).

When the pressure P ₀ is equal to or larger than the threshold value P ₀ ^* when the test piece 3 is opened, that is, when the gas amount Q (pressure) of the residual gas is large, the residual gas is passed through the orifice 5 from the intermediate chamber 4 through the second orifice 5. After moving to the analysis room 7, the residual gas is measured and analyzed using the mass spectrometer MS2 in the second analysis room 7. At this time, it is necessary that the pressure in the second analysis chamber 7 does not become higher than the upper limit pressure of the mass spectrometer MS2.

  The gas analyzer 100 gradually flows the residual gas of the test specimen 3 into the second analysis chamber 7 through the orifice 5, and exhausts the residual gas flowing from one to the next through the orifice 5 by the exhaust unit 8. The pressure rise due to the residual gas in the second analysis chamber 7 is suppressed. With this mechanism, the pressure of the residual gas in the second analysis chamber 7 is kept lower than the upper limit pressure of the mass spectrometer MS2, and even when the amount of the residual gas in the specimen 3 is large, the mass spectrometer MS2 Measurement at

The value of the vacuum gauge G0, that is, when the pressure P ₀ of the sample chamber 1 is less than the threshold value P ₀ ^*, the control arithmetic unit 9, opens the first analysis chamber 6 and the vacuum valve VV2 between the intermediate chamber 4, Alternatively, the vacuum valve VV1 separating the sample chamber 1 and the intermediate chamber 4 is opened in a state where the sample chamber 1 is open (Step S110). By opening the vacuum valve VV1, the residual gas spreads from the intermediate chamber 4 to the first analysis chamber 6. Then, the mass spectrometer MS1 in the first analysis chamber 6 measures and analyzes the residual gas (Step S111).

When the pressure P ₀ is less than the threshold value P ₀ ^* when the test piece 3 is opened, that is, when the gas amount Q (pressure) of the residual gas is small, the residual gas is first discharged from the intermediate chamber 4 through the vacuum valve VV2. And the residual gas is measured and analyzed using the mass spectrometer MS1 in the first analysis chamber 6. At this time, it is necessary that the pressure in the first analysis chamber 6 also does not become higher than the upper limit pressure of the mass spectrometer MS1. However, the value less than the threshold value P ₀ ^* is assumed to be smaller than the upper limit pressure of the mass spectrometer MS1, and the residual gas led to the first analysis chamber 6 is at the upper limit pressure of the mass spectrometer MS1. Never exceed. Details will be described later.

  The residual gas of the specimen 3 flows into the first analysis chamber 6 through the vacuum valve VV2. The inner diameter of the pipe of the vacuum valve VV2 and the diameter of the vacuum valve are much larger than the inner diameter of the orifice 5. Therefore, since more gas molecules move to the first analysis chamber 6 than gas molecules exhausted from the intermediate chamber 4 through the orifice 5, measurement by the mass spectrometer MS1 becomes possible.

  On the other hand, since the exhaust section 8 is provided in the second analysis chamber 7, the residual gas that has moved to the intermediate chamber 4 and the first analysis chamber 6 passes through the orifice 5 of the intermediate chamber 4 for the second analysis. The gas gradually moves to the chamber 7 and is further exhausted by the exhaust unit 8.

In the present embodiment, it is assumed that the exhaust unit 8 operates continuously even when the pressure P ₀ is less than the threshold value P ₀ ^*. However, the present invention is not limited to this. May be controlled so that the operation of the exhaust unit 8 is stopped when it is determined that the pressure P ₀ is less than the threshold value P ₀ ^* .

The mass spectrometer MS1 or the mass spectrometer MS2 ends the measurement when the measurement and the analysis are completed by either (step S112). When the measurement is completed, the control and arithmetic unit 9 closes the vacuum valve VV1 (Step S113), opens the sample chamber 1 to the atmosphere, and allows the specimen 3 to be taken out (Step S114). Next, the threshold value P ₀ ^* will be described. The threshold value P ₀ ^* is determined based on the relationship between the pressure in the sample chamber 1 and the pressure in the first analysis chamber 6.

Here, V ₁ the volume of the first analysis chamber _6, the volume of the intermediate chamber 4 V _c, the first pressure of the analysis chamber for when opening the sample chamber 1 and the vacuum valve VV1, VV2 was P ₁ Then, P ₁ can be expressed as P ₁ = (V ₀ / (V ₀ + V _c + V ₁ )) × P ₀ .

That is, when the upper limit pressure at which the mass spectrometer MS1 can operate is P qms , when the vacuum valves VV1 and VV2 are opened, the pressure P1 of the first analysis chamber 6 becomes the operating pressure of the mass spectrometer MS1. when the pressure P 0 of the sample chamber 1 to be the upper limit P qms was P 0 *, P 0 * is P 0 * = ((V 0 + V c + V 1) / V 0) expressed as × P qms.

Therefore, by setting the threshold value to P ₀ ^* , when the pressure of the residual gas does not exceed the upper limit of the operating pressure of the mass spectrometer MS1, the gas analyzer 100 operates the mass spectrometer MS1 of the first analysis chamber 6. When the operating pressure exceeds the upper limit of the operating pressure, the gas analyzer 100 uses the mass spectrometer MS2 in the second analysis chamber 7 to narrow down the amount (pressure) of the residual gas for measurement and analysis. Can be.

Here, as an example, the threshold value is P ₀ ^* calculated based on the upper limit P _qms of the operating pressure of the mass spectrometer, but is not limited thereto. The threshold value may be a value appropriately set by a user using the gas analyzer 100, and may be, for example, P ₀ ^* obtained at a pressure equal to or less than Pqms.

FIG. 4 is a graph showing an example of the relationship between the pressure in the sample chamber 1 of the gas analyzer 100 and the pressure in the first analysis chamber 6 immediately after opening the vacuum valve VV1. The horizontal axis in FIG. 4 shows the pressure P ₀ of the sample chamber 1 after the test piece 3 is opened, and the vertical axis shows the pressure P ₁ of the first analysis chamber 6 when the vacuum valve VV 1 of the test piece 3 is opened. . Plot in the figure is an example showing the relationship between P ₁ for each P ₀ at the time of opening the specimen 3.

In the gas analyzer 100 of the present invention, _{P 0} and the relationship _{P 1,} the volume _{V 0} which the sample chamber 1, and the volume _{V c} of the intermediate chamber 4, the volume _{V 1} of the first analysis chamber 6, and the test with a hollow structure inside the volume _{V s} of the body _3, represented as _{P 1 = (V 0 / (} V 0 + V c + V 1)) × P 0. In the relationship between P ₀ and P _{1 in} FIG. 4, if the operating upper limit pressure P _qms of the mass spectrometer MS1 is determined, the threshold P ₀ ^* of the pressure P ₀ of the sample chamber 1 for determining the analysis chamber used for gas analysis ^. Can be uniquely determined.

  FIG. 5 is a graph showing an example of a temporal change in the pressure in the first analysis chamber 6 before and after opening and closing the vacuum valve VV1 when performing gas analysis in the first analysis chamber 6 in the gas analyzer 100. When the vacuum valve VV1 is opened, the residual gas in the specimen 3 that has spread in the sample chamber 1 instantaneously spreads to the intermediate chamber 4 and further to the first analysis chamber 6 (when the vacuum valve VV2 is open). ).

  The pressure inside the first analysis chamber 6 increases due to the residual gas of the test body 3 that has spread to the first analysis chamber 6. The pressure is measured by the vacuum gauge G1, and the measured pressure and the ion intensity of each mass-to-charge ratio measured by the mass spectrometer MS1 are input to the control calculation unit 9 and calculated. Obtains the partial pressure and composition of the residual gas of the test body 3.

  For example, when obtaining the partial pressure of nitrogen as a residual gas in the first analysis chamber 6, the first analysis chamber 6 is filled with only nitrogen gas, and the mass spectrometer MS1 of the mass spectrometer MS1 accompanies a change in pressure in the first analysis chamber 6. Obtain the relationship with the detection intensity. When the residual gas in which a plurality of types of gases are mixed is analyzed in the first analysis chamber 6, the residual gas nitrogen is detected based on the detected intensity of the nitrogen gas for each time in the measurement data of the mass spectrometer MS1. Can be obtained over time.

  The method is not limited to the method in which the first analysis chamber 6 is filled with only nitrogen gas. The partial pressure of nitrogen gas and the mass spectrometer are measured by using a mixed gas in which a plurality of types of gases having known partial pressures of nitrogen are mixed. The relationship between the detection intensities of MS1 may be obtained, and the temporal change of the partial pressure of nitrogen in the residual gas may be obtained from the detection intensities of nitrogen gas for each time in the measurement data of mass spectrometer MS1.

  FIG. 6 shows a time change of the pressure in the second analysis chamber 7 before and after opening and closing the vacuum valve VV1 when performing the gas analysis in the second analysis chamber 7 in the gas analyzer 100 according to the first embodiment of the present invention. 5 is a graph showing an example of the above. When the vacuum valve VV <b> 1 is opened, the residual gas in the test piece 3 spread in the sample chamber 1 spreads instantaneously into the intermediate chamber 4. The residual gas that has moved to the intermediate chamber 4 moves to the second analysis chamber 7 through the orifice 5 of the intermediate chamber 4.

  The pressure inside the second analysis chamber 7 increases due to the internal gas of the specimen 3 that has moved to the second analysis chamber 7. The pressure is measured by the vacuum gauge G2, and the measured pressure and the ionic strength of each mass-to-charge ratio measured by the mass spectrometer MS2 are input to the control calculation unit 9 and calculated. , The partial pressure and composition of the residual gas inside the test piece 3 are obtained.

  As in the case of the first analysis chamber 6, the partial pressure in the second analysis chamber 7 is combined with the measurement data if the relationship between the partial pressure of nitrogen gas and the detection intensity of the mass spectrometer MS2 can be obtained, for example. Thus, a temporal change in the partial pressure of the nitrogen gas can be obtained. The relationship between the nitrogen gas and the detection intensity of the mass spectrometer MS2 is, for example, a value obtained by introducing a mixed gas having a known nitrogen partial pressure into the sample chamber 1 and measuring the nitrogen partial pressure in the second analytical chamber 7 by the vacuum gauge G2. And the intensity of the nitrogen gas detected by the mass spectrometer MS2.

According to the present invention, a sample sealing structure is formed from a small amount of residual gas in a test piece 3 having a small cavity of less than 1 mm ³ and being vacuum-tightly sealed like an uncooled infrared sensor or a vacuum-sealed MEMS device. In this case, it is possible to perform both the analysis and the leakage of the residual gas inside the sealing structure, due to an increase in the pressure of the residual gas inside due to degassing generated from a member inside the sealing structure for some reason. According to the present embodiment, it is possible to analyze the residual gas in the hermetically sealed device corresponding to a wider pressure range than ever before.

Embodiment 2 FIG.
In this embodiment, the second analysis chamber 7 and the first analysis chamber 6 are connected by a vacuum valve VV3, and the second analysis chamber 7 does not have the mass spectrometer MS2. Are different.

  FIG. 7 is a schematic diagram showing a configuration of a gas analyzer 200 according to the second embodiment. As illustrated in FIG. 7, the gas analyzer 200 of the present embodiment is different from the gas analyzer 100 of the first embodiment in that the second analysis chamber 7 is provided with a vacuum valve VV3, And the first analysis chamber 6 are connected via a vacuum valve VV3. Further, the vacuum valve VV3 is connected to the control arithmetic unit 9.

  Further, the configuration differs from the first embodiment in that the vacuum gauge G2 and the mass spectrometer MS2 provided in the second analysis chamber 7 in the first embodiment are omitted. A gate valve is used as the vacuum valve VV3. The vacuum valve VV3 closes and opens the space between the first analysis chamber 6 and the second analysis chamber 7 by opening and closing the valve.

  In the second embodiment, the measurement of the partial pressure performed in the second analysis chamber 7 in the first embodiment can be performed in the first analysis chamber 6 by opening and closing a vacuum valve. Therefore, the valve opening / closing method in the analysis procedure is different from that of the first embodiment.

  The second embodiment differs from the first embodiment only in the above points, and the outline of the second embodiment is the same as that of the first embodiment. Therefore, the same reference numerals are given to the same elements, and the description thereof will be omitted. Next, a procedure for analyzing the residual gas of the test body 3 using the gas analyzer 200 according to the second embodiment will be described with reference to the flowchart of FIG.

  FIG. 8 is a flowchart illustrating a gas analysis method using the gas analyzer 200 according to the second embodiment. Here, only the flow different from the first embodiment will be described. The other description is the same as that in the first embodiment, and thus will not be described. Specifically, since there is no mass spectrometer and vacuum gauge in the second analysis chamber 7, the analysis in the first analysis chamber 6 via the vacuum valve VV3 is different from the first embodiment.

  The selection of the analysis chamber is the same as that of the first embodiment in that it is determined based on the relationship between the pressure of the sample chamber 1 and the pressure of the first analysis chamber 6, but in this embodiment, the vacuum valve is used. The operation method is different from that of the first embodiment, and will be described.

Measured value of the vacuum gauge G0 is explained when the threshold P ₀ ^* or more. The value of the vacuum gauge G0, that is, when the pressure P ₀ of the sample chamber 1 is the threshold value P ₀ ^* above, the control arithmetic unit 9 closes the vacuum valve VV2 located between the first analysis chamber 6 and the intermediate chamber 4 Then, the vacuum valve VV3 between the first analysis chamber 6 and the intermediate chamber 4 is opened (Step S201).

  Here, in step S201, the control arithmetic unit 9 controls to open the vacuum valve VV3. However, the present invention is not limited to this. If the vacuum valve VV3 is already open, it is not necessary to perform the opening control. Good. When the vacuum valve VV <b> 1 is opened (Step S <b> 110), the residual gas in the specimen 3 that has spread in the sample chamber 1 instantaneously spreads in the intermediate chamber 4.

  The residual gas that has moved to the intermediate chamber 4 moves to the second analysis chamber 7 through the orifice 5 of the intermediate chamber 4. Then, the residual gas in the specimen 3 that has moved to the second analysis chamber 7 spreads to the first analysis chamber 6 via the vacuum valve VV3, and the pressure in the first analysis chamber 6 increases. The pressure is measured by the vacuum gauge G1. Further, the partial pressure of the residual gas in the test body 3 is obtained by being calculated by the control calculation unit 9 based on the measurement values obtained by the mass spectrometer MS1 and the vacuum gauge G1.

Measured value of the vacuum gauge G0 is explained when the threshold P ₀ ^* less than. When it is less than the threshold value P ₀ ^* , if it is determined No in step S106, the control arithmetic unit 9 closes the vacuum valve VV3 (step S202). By closing the vacuum valve VV3, the space between the first analysis chamber 6 and the second analysis chamber 7 is shut off.

  Next, the control arithmetic unit 9 opens the vacuum valve VV1 (Step S110). When the vacuum valve VV1 is opened, the residual gas in the specimen 3 that has spread into the sample chamber 1 is instantaneously spread to the first analysis chamber 6 through the intermediate chamber 4 (the vacuum valve VV2 is open). Subsequent processes of measurement and analysis transfer by the mass spectrometer MS1 are the same as those in the first embodiment, and thus description thereof will be omitted.

  The operation and effect of the present embodiment will be described. In the second embodiment, the number of mass spectrometers and the number of vacuum gauges are each smaller than that of the first embodiment by one. Since there are few instruments, it is possible to save the space of the device and reduce the frequency of maintenance.

  Further, in the second embodiment, since the vacuum valve VV3 functions as a pipe as a bypass to the intermediate chamber 4 and the sample chamber 1, the vacuum valve VV3 and the vacuum valve VV3 are evacuated after the test piece 3 is set. By opening the valve VV2, the first analysis chamber 6, the intermediate chamber 4, and the sample chamber 1 can be evacuated more quickly. Note that, in the present embodiment, portions different from the first embodiment have been described. Other parts are the same as in the first embodiment.

Embodiment 3 FIG.
The present embodiment is different from the first embodiment in that the orifice 5 is a variable orifice 12 that varies the conductance. Further, by using the variable orifice 12 for the orifice 5, processing different from that in the first embodiment occurs in the analysis. Therefore, different parts will be described.

  FIG. 9 is a schematic diagram showing a configuration of a gas analyzer 300 according to the third embodiment. The gas analyzer 300 of the present embodiment shown in FIG. 9 includes a variable orifice 12 instead of the orifice 5 as compared with the gas analyzer 100 of the first embodiment. Further, the second embodiment is different from the first embodiment in that a process of adjusting the conductance of the variable orifice 12 is added in the analysis procedure.

  The third embodiment differs from the first embodiment only in the above points, and the outline of the third embodiment is the same as that of the first embodiment. Therefore, the same reference numerals are given to the same elements, and the description thereof will be omitted.

  FIG. 10 is a schematic diagram showing a configuration of the variable orifice 12 used in the gas analyzer 300 according to the third embodiment. The variable orifice 12 is provided with a plurality of orifices 13 made of, for example, small holes in a metal disk so as to be arranged in a circumferential direction around a central axis 14 of the metal disk. In addition, the hole diameters of the orifices 13 may be all the same or may be different.

  The variable orifice 12 has a semicircular or fan-shaped lid 15. The lid 15 rotates around the central axis 14 to close the orifice 13. The control operation unit 9 controls the rotation angle of the lid 15 to change the number of the orifices 13 to be closed, thereby changing the conductance of the variable orifice 12.

The combined conductance C _TP of the variable orifice 12 by the plurality of orifices 13 is the sum of the conductances C _n of the orifices 13. For example, when ten orifices 13 are provided, C _TP = C ₁ + C ₂ +... + C ₁₀ . Is represented by the sum of the respective conductances.

  FIG. 11 is a flowchart illustrating a gas analysis method using the gas analyzer 300 according to the third embodiment. The method of analyzing gas in the present embodiment will be described with reference to the flowchart of FIG. The description of the same parts as in the first embodiment is omitted.

  In the present embodiment, as in the first embodiment, an analysis chamber for measurement and analysis is selected based on the amount of residual gas in the test body 3 measured by the vacuum gauge G0. The selection of the analysis chamber is the same as that of the first embodiment in that it is determined based on the pressure of the sample chamber 1 which is proportional to the gas amount of the residual gas, but in the present embodiment, the variable orifice 12 This embodiment is different from the first embodiment in that the operation of conductance adjustment is added.

First, the measured value of the vacuum gauge G0 is, for the time less than P ₀ ^* is the gas analyzer 300, as shown in the flowchart of FIG. 11, as in the first embodiment, the residual in the first analysis chamber 6 Measure and analyze gas. After that, in the third embodiment, the control arithmetic unit 9 adjusts the conductance of the variable orifice 12 (Step S301). An example of the adjustment method will be described with reference to FIG.

Figure 12 shows an example of a temporal change of the pressure in the first analysis chamber 6 before and after the opening and closing of the vacuum valve VV1 calculated by based on the control arithmetic unit 9 the pressure P ₁ of the sample chamber 1. 12 Among the numerical aperture of the orifice 13 of the variable orifice 12, one each, three, shows the pressure P ₁ of the first analysis chamber 6 at each conductance obtained when changing the 10 I have.

In FIG. 12, the plot having a numerical aperture of 10 indicates that the residual gas is exhausted within a few seconds after opening the vacuum valve VV ₁ , and the pressure P ₁ reaches the background pressure p ₁ of the first analysis chamber 6. In other words, it can be seen that when the numerical aperture is 10, a measurement point sufficient for analyzing the partial pressure by the mass spectrometer MS1 cannot be obtained. On the other hand, when the numerical aperture of the orifice 13 in the variable orifice 12 is closed by the lid 15 and the conductance is reduced, the number of measurement points can be increased as shown in the plot of the numerical aperture 3 and the numerical aperture 1 in the figure.

  However, if the conductance is too small, the slope of the graph becomes smaller, and the pressure due to gas release from the inner wall surface of the room (the sample room 1, the intermediate room 4, the first analysis room 6, and the second analysis room 7). The effects of the rise cannot be ignored. In this case, too, the accuracy of the analysis in the partial pressure measurement is reduced, so that the control arithmetic unit 9 performs an adjustment to increase the conductance and increase the flow rate of the gas exhausted from the first analysis chamber 6.

  When the residual gas is measured and analyzed in the first analysis chamber 6 as described above, the exhaust from the first analysis chamber 6 becomes too large or too small depending on the pressure in the first analysis chamber 6. The control arithmetic unit 9 adjusts the conductance of the variable orifice 12 so as not to cause such a situation. Here, the conductance is adjusted according to the pressure of the first analysis chamber 6, but the present invention is not limited to this, and the conductance may be adjusted according to the amount of residual gas. The conductance may be adjusted according to the pressure, and the manner of adjustment is not limited.

Subsequently, when the measurement value of the vacuum gauge G0 is equal to or ^larger than the threshold value P ₀ ^* , as shown in the flowchart of FIG. Perform measurement and analysis of residual gas in. Thereafter, the control arithmetic unit 9 adjusts the conductance of the variable orifice 12 (Step S302). An example of the adjustment method will be described with reference to FIG.

Figure 13 shows an example of a temporal change of the pressure in the second analysis chamber 7 before and after the opening and closing of the vacuum valve VV1 calculated by based on the control arithmetic unit 9 the pressure P ₁ of the sample chamber 1. In Figure 13, the numerical aperture of the orifice 13 of the variable orifice 12, one each, three, shows the pressure P ₂ of the second analysis chamber 7 at each conductance obtained when changing the 10 I have.

In FIG. 13, when the numerical aperture is 10, the pressure in the second analysis chamber 7 exceeds P _qms (= 1.0 × 10 ⁻³ Pa) immediately after the vacuum valve VV1 is opened, and immediately remains. It is shown that sufficient measurement points cannot be obtained because the gas has been exhausted.

In this case, the control arithmetic unit 9 closes the opening of the variable orifice 12 with the lid 15, and reduces the conductance as in the numerical aperture 3 and the numerical aperture 1. This allows the gas analyzer 300 to secure measurement points while keeping the pressure in the second analysis chamber 7 below P _qms .

  However, if the conductance is too small, the amount of residual gas introduced into the second analysis chamber 7 per unit time is small, and the pressure change in the second analysis chamber 7 before and after opening and closing the vacuum valve VV1 is small. Too much. In this case, too, the accuracy of the analysis in the partial pressure measurement is reduced, so that the control operation device 9 performs adjustment to increase the conductance and increase the gas flow rate of the residual gas to the second analysis chamber 7.

  As described above, when the residual gas is measured and analyzed in the second analysis chamber 7, the exhaust from the intermediate chamber 4 does not become too large or too small according to the pressure of the second analysis chamber 7. , The control arithmetic unit 9 adjusts the conductance of the variable orifice 12. Here, the conductance is adjusted according to the pressure of the second analysis chamber 7, but the present invention is not limited to this, and the conductance may be adjusted according to the gas amount of the residual gas. The conductance may be adjusted according to the pressure, and the manner of adjustment is not limited.

  After the conductance adjustment, the operation is the same as that of the first and second embodiments, and thus the description is omitted. The operation and effect of the present embodiment will be described. In the present embodiment, since the detection sensitivity is adjusted after the analysis chamber is selected by providing the variable orifice 12, the accuracy is higher than in the first and second embodiments. It becomes possible to carry out partial pressure measurement of gas. Note that, in the present embodiment, portions different from the first embodiment have been described. Other parts are the same as in the first embodiment.

  In the gas analyzer of the present invention, the gas released from the inner wall surface of each room (the sample room 1, the intermediate room 4, the first analysis room 6, and the second analysis room 7) is a vacuum gauge and a mass spectrometer. As a background, measurement accuracy is adversely affected.

  Therefore, the material used for each room is composed of a material that emits little gas, and it is necessary to reduce the surface area of the inner wall surface as much as possible by performing surface treatment by polishing or etching to reduce gas emission. desirable. Furthermore, when performing vacuuming, each room (the sample room 1, the intermediate room 4, the first analysis room 6, and the second analysis room 7) should be baked from the outside by a heating device such as a rubber heater. Is also desirable.

  Note that the gas analyzer and the gas analysis method of the present invention deviate from the gist of the present invention as long as the conditions that can handle the motion of gas molecules as a molecular flow in each room of the gas analyzer and the orifice are satisfied. Various modifications can be made without departing from the scope of the present invention.

1: sample chamber, 2: opener, 3: test specimen, 4: intermediate chamber, 5: orifice, 6: first analysis chamber, 7: second analysis chamber, 8: exhaust unit, 9: control operation unit , 10: communication path, 12: variable orifice, 13: orifice, VV1, VV2, VV3: vacuum valve, G0, G1, G2: vacuum gauge, MS1, MS2: mass spectrometer, 100, 200, 300: gas analyzer

Claims (5)

A sample chamber for taking out residual gas from the specimen in a vacuum,
The sample chamber in a vacuum, an intermediate chamber connected so as to take in the residual gas from the sample chamber via a first vacuum valve,
The intermediate chamber in a vacuum, a first analysis chamber connected to be able to take in the residual gas from the intermediate chamber via a second vacuum valve,
The intermediate chamber in a vacuum, a second analysis chamber connected to be able to take in the residual gas from the intermediate chamber via an orifice,
A vacuum gauge for measuring a gas amount of the residual gas in the sample chamber,
An exhaust unit that exhausts the residual gas from the second analysis chamber,
The second vacuum valve is closed when the gas amount is greater than or equal to a threshold, and the second vacuum valve is opened when the gas amount is less than the threshold, and the vacuum gauge reduces the gas amount of the residual gas. A control operation unit that opens the first vacuum valve after measurement,
When the gas amount is equal to or greater than the threshold, the residual gas taken into the second analysis chamber is analyzed, and when the gas amount is less than the threshold, the residual gas is taken into the first analysis chamber. A gas analyzer comprising: one or more mass spectrometers for analyzing residual gas. Wherein the mass spectrometer is
A first mass spectrometer installed in the first analysis chamber and analyzing the residual gas taken into the first analysis chamber when the gas amount is less than the threshold,
A second mass spectrometer installed in the second analysis chamber and analyzing the residual gas taken into the second analysis chamber when the gas amount is equal to or greater than the threshold,
The gas analyzer according to claim 1, wherein The first analysis chamber is connected to be able to take in the residual gas via the second analysis chamber and a third vacuum valve, the control operation unit,
Opening the third vacuum valve when the gas amount is equal to or more than the threshold, closing the third vacuum valve when the gas amount is less than the threshold,
Wherein the mass spectrometer is
Installed in the first analysis chamber, when the gas amount is equal to or more than the threshold, analyze the residual gas taken into the second analysis chamber, when the gas amount is less than the threshold, the The gas analyzer according to claim 1, wherein the residual gas taken into the first analysis chamber is analyzed. The control operation unit,
The gas analyzer according to any one of claims 1 to 3, wherein the conductance of the orifice is adjusted according to a gas amount of the residual gas. Removing residual gas from the specimen in the sample chamber;
Measuring the gas amount of the residual gas,
When the gas amount of the residual gas is less than a threshold value, the intermediate gas connected to the sample chamber and the first analysis chamber connected via a vacuum valve, with the vacuum valve open, the residual gas Taking from the sample chamber into the first analysis chamber;
When the gas amount of the residual gas is equal to or greater than the threshold value, with the vacuum valve closed, the residual gas is passed through an orifice to a second analysis chamber connected to the intermediate chamber via an orifice. Taking from the sample chamber into the second analysis chamber;
Analyzing the residual gas taken into the first analysis chamber and the second analysis chamber by a mass spectrometer,
A gas analysis method comprising:

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