Vacuum gauge with

Abstract

To suppress a measurement error of a vacuum gauge due to a thermal transition phenomenon.SOLUTION: A first relationship indicating heat transfer between the first temperature T1 measured by the first temperature sensor 105, the first pressure value p1 measured by the first vacuum sensor 101, and the first pipe diameter d1 of the first pressure introduction pipe 106, and the pressure p0 in the vacuum tank 105, and a second relationship indicating heat transfer between the second temperature T2 measured by the second temperature sensor 106, the second pressure value p2 measured by the second vacuum sensor 103, and the second pipe diameter d2 of the second pressure introduction pipe 107, and the pressure p0 in the vacuum tank 105. The pressure in the vacuum chamber 105 is determined.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vacuum gauge. [Background technology]

[0002] Vacuum gauges such as diaphragm vacuum gauges have a sensor container containing a vacuum sensor including a diaphragm attached to the vacuum chamber to be measured via a pressure introduction tube, and convert the amount of deflection of the diaphragm when pressure is applied, i.e., displacement, into a pressure value for output. This type of vacuum gauge is widely used in industrial applications, including semiconductor equipment, because it has little dependency on the type of gas.

[0003] Incidentally, semiconductor process gases used in semiconductor equipment that uses vacuum gauges tend to liquefy or solidify. As a result, liquefied or solidified components adhere to the pressure introduction tube to the vacuum sensor and the vacuum sensor inside the sensor container (measurement chamber), affecting measurements. To prevent this adhesion of process gas, the sensor container is heated (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-002986 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in a low-pressure region, when two spaces with different temperatures are connected by a thin pipe, a pressure difference occurs between the two (thermal transition phenomenon). In the vacuum gauge mentioned above, the sensor vessel is heated to, for example, about 100°C to prevent adhesion of process gas, but the vacuum chamber where processing takes place may be heated to a higher or lower temperature. If the temperatures differ between the vacuum chamber and the sensor vessel in this way, a pressure difference occurs due to thermal transition, resulting in measurement errors.

[0006] The present invention has been made to solve the above problems, and has as its object to suppress measurement errors in vacuum gauges caused by thermal transition phenomena. [Means for solving the problem]

[0007] The vacuum gauge of the present invention comprises a first sensor container that houses a first vacuum sensor, a second sensor container that houses a second vacuum sensor, a first temperature sensor that measures the temperature of the first vacuum sensor, a second temperature sensor that measures the temperature of the second vacuum sensor, a first pressure introduction tube that introduces the pressure of the medium to be measured in a vacuum chamber whose pressure is to be measured to the first sensor container, a second pressure introduction tube that introduces the pressure of the medium to be measured in the vacuum chamber to the second sensor container, and a thermal transition correction circuit configured to determine the pressure in the vacuum chamber from a first temperature measured by the first temperature sensor, a first pressure value measured by the first vacuum sensor, and a first relationship that indicates thermal transition between the diameter of the first pressure introduction tube and the pressure in the vacuum chamber, and a second temperature that is different from the first temperature measured by the second temperature sensor, a second pressure value measured by the second vacuum sensor, and a second relationship that indicates thermal transition between the diameter of the second pressure introduction tube and the pressure in the vacuum chamber.

[0008] In one configuration example of the above vacuum gauge, the pipe diameter of the first pressure introducing pipe is different from the pipe diameter of the second pressure introducing pipe.

[0009] The vacuum gauge of the present invention comprises a first sensor container that houses a first vacuum sensor, a second sensor container that houses a second vacuum sensor, a first temperature sensor that measures the temperature of the first vacuum sensor, a second temperature sensor that measures the temperature of the second vacuum sensor, a first pressure introduction pipe that introduces the pressure of a medium to be measured in a vacuum chamber whose pressure is to be measured to the first sensor container, a second pressure introduction pipe having a different diameter from the first pressure introduction pipe that introduces the pressure of the medium to be measured in the vacuum chamber to the second sensor container, and a thermal transition correction circuit configured to determine the pressure in the vacuum chamber from the first temperature measured by the first temperature sensor, the first pressure value measured by the first vacuum sensor, and a first relationship that indicates thermal transition between the diameter of the first pressure introduction pipe and the pressure in the vacuum chamber, and the second temperature measured by the second temperature sensor, the second pressure value measured by the second vacuum sensor, and a second relationship that indicates thermal transition between the diameter of the second pressure introduction pipe and the pressure in the vacuum chamber.

[0010] The vacuum gauge of the present invention comprises a sensor container that houses a vacuum sensor, a temperature sensor that measures the temperature of the vacuum sensor, a pressure introduction tube that introduces the pressure of a medium to be measured in a vacuum chamber whose pressure is to be measured to the sensor container, and a thermal transition correction circuit configured to determine the pressure in the vacuum chamber from a first temperature measured by the temperature sensor, a first pressure value measured by the vacuum sensor, and a first relationship that indicates thermal transition between the diameter of the pressure introduction tube and the pressure in the vacuum chamber, and a second temperature different from the first temperature measured by the temperature sensor, a second pressure value measured by the vacuum sensor, and a second relationship that indicates thermal transition between the diameter of the tube and the pressure in the vacuum chamber.

[0011] In one configuration example of the vacuum gauge, the first pressure value and the second pressure value are measured at different times. [Effects of the Invention]

[0012] As described above, according to the present invention, the pressure inside the vacuum chamber is determined from a first relationship between the first temperature of the first vacuum sensor and the first pressure value measured by the first vacuum sensor, and a second relationship between the second temperature of the second vacuum sensor and the second pressure value measured by the second vacuum sensor, thereby suppressing measurement errors in the vacuum gauge due to thermal transition phenomena. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the configuration of a vacuum gauge according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a configuration diagram showing the configuration of another vacuum gauge according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the configuration of a vacuum gauge according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] A vacuum gauge according to an embodiment of the present invention will now be described.

[0015] [Embodiment 1] First, a vacuum gauge according to a first embodiment of the present invention will be described with reference to Fig. 1. This vacuum gauge includes a first vacuum sensor 101, a first sensor container 102 that houses the first vacuum sensor 101, a second vacuum sensor 103, a second sensor container 104 that houses the second vacuum sensor 103, a first temperature sensor 105, a second temperature sensor 106, a vacuum chamber 107, a first pressure introduction pipe 108, a second pressure introduction pipe 109, and a thermal transition compensation circuit 110.

[0016] The first temperature sensor 105 measures the temperature of the first vacuum sensor 101. The second temperature sensor 106 measures the temperature of the second vacuum sensor 103. For example, the first vacuum sensor 101 is heated by heating the inside of the first sensor container 102 with a heater 112 provided to surround the outer peripheral surface of the first sensor container 102. The temperature of the first vacuum sensor 101 heated in this manner is measured by the first temperature sensor 105. Similarly, the second vacuum sensor 103 is heated by heating the inside of the second sensor container 104 with a heater 113 provided to surround the outer peripheral surface of the second sensor container 104. The temperature of the second vacuum sensor 102 heated in this manner is measured by the second temperature sensor 106. The heaters 112 and 113 are controlled by a control circuit (not shown). The heaters 112 and 113 can also be controlled by a thermal transition compensation circuit 110. The first vacuum sensor 101 and the second vacuum sensor 103 may be, for example, well-known diaphragm gauges.

[0017] The first pressure introduction pipe 108 is a pipe that introduces the pressure of the medium to be measured in the vacuum chamber 107, the pressure of which is to be measured, to the first sensor chamber 102. The second pressure introduction pipe 109 is a pipe that introduces the pressure of the medium to be measured in the vacuum chamber 107 to the second sensor chamber 104. As shown in FIG. 2 , the first pressure introduction pipe 108 and the second pressure introduction pipe 109 can be connected to the vacuum chamber 107 via a common introduction pipe 111.

[0018] The thermal transition correction circuit 110 calculates the pressure in the vacuum chamber 107 from a first relationship indicating the thermal transition between the first temperature T1 measured by the first temperature sensor 105, the first pressure value p1 measured by the first vacuum sensor 101, and the first pipe diameter d1 of the first pressure introduction pipe 108, and the pressure p0 in the vacuum chamber 107, and a second relationship indicating the thermal transition between the second temperature T2 measured by the second temperature sensor 106, the second pressure value p2 measured by the second vacuum sensor 103, and the second pipe diameter d2 of the second pressure introduction pipe 109, and the pressure p0 in the vacuum chamber 107.

[0019] For example, a first relationship indicating thermal transition among the first temperature T1 measured by the first temperature sensor 105, the first pressure value p1 measured by the first vacuum sensor 101, the first pipe diameter d1 of the first pressure introduction pipe 108, and the pressure p0 inside the vacuum chamber 107 can be expressed by the following formula (1): where A, B, and C are constants depending on the gas type.

[0020]

number

[0021] Furthermore, a second relationship showing thermal transition among the second temperature T2 measured by the second temperature sensor 106, the second pressure value p2 measured by the second vacuum sensor 103, the second pipe diameter d2 of the second pressure introducing pipe 109, and the pressure p0 inside the vacuum chamber 107 can be expressed by the following formula (2). Note that T0 is the temperature inside the vacuum chamber 107.

[0022]

number

[0023] By solving the simultaneous equations of the relational expression (1) between p0 and p1, which represents the first relationship, and the relational expression (2) between p0 and p2, which represents the second relationship, it is possible to obtain the following calculation formula (3) for calculating the pressure p0 inside the vacuum chamber 107. The thermal transition correction circuit 110 can calculate the pressure p0 inside the vacuum chamber 107 using calculation formula (3). The thermal transition correction circuit 110 outputs the calculated pressure p0 as a pressure measurement value from the vacuum gauge.

[0024]

number

[0025] Here, the above-mentioned formula (3) for determining the pressure p0 inside the vacuum chamber 107 can be calculated in advance, and the calculated formula (3) can be set in the thermal transition correction circuit 110.

[0026] Furthermore, by solving the simultaneous equations of relational expressions (1) and (2), it is possible to obtain the following calculation formula (4) for calculating the temperature T0 inside the vacuum chamber 107. The thermal transition correction circuit 110 can calculate the temperature T0 inside the vacuum chamber 107 using calculation formula (4). The thermal transition correction circuit 110 can output the calculated temperature T0.

[0027]

number

[0028] Furthermore, the thermal transition correction circuit 110 calculates p0 by varying T0 in relational expressions (1) and (2), and can find the solution of T0 and p0 when the difference between p0 is smallest (mathematical optimization program).

[0029] In the above description, the first temperature of the first vacuum sensor 101 measured by the first temperature sensor 105 and the second temperature of the second vacuum sensor 103 measured by the second temperature sensor 106 are different, but this is not limited to this. Even if the first temperature and the second temperature are the same, the first pipe diameter d1 of the first pressure introduction pipe 108 and the second pipe diameter d2 of the second pressure introduction pipe 109 can be set to different values, and the pressure p0 inside the vacuum chamber 107 can be calculated using relational expressions (1) and (2). Furthermore, the first temperature of the first vacuum sensor 101 measured by the first temperature sensor 105 and the second temperature of the second vacuum sensor 103 measured by the second temperature sensor 106 can be set to different values, and the first pipe diameter d1 of the first pressure introduction pipe 108 and the second pipe diameter d2 of the second pressure introduction pipe 109 can be set to different values, and the pressure p0 inside the vacuum chamber 107 can be calculated using relational expressions (1) and (2).

[0030] [Embodiment 2] Next, a vacuum gauge according to a second embodiment of the present invention will be described with reference to Fig. 3. This vacuum gauge includes a vacuum sensor 201, a sensor container 202 that houses the vacuum sensor 201, a temperature sensor 203 that measures the temperature of the vacuum sensor 201, a vacuum chamber 204 whose pressure is to be measured, a pressure introduction pipe 205, and a thermal transition compensation circuit 206.

[0031] The temperature of the vacuum sensor 201 is controlled, for example, by heating the inside of the sensor container 202 using a heater 211 provided to surround the outer periphery of the sensor container 202. This temperature control is controlled by a control circuit (not shown). This temperature control can also be performed by controlling the heater 211 using a thermal transition correction circuit 206.

[0032] In the second embodiment, the thermal transition correction circuit 206 calculates the pressure in the vacuum chamber 204 from a first relationship indicating the thermal transition between the first temperature measured by the temperature sensor 203, the first pressure value measured by the vacuum sensor 201, and the diameter of the pressure introduction tube 205 and the pressure in the vacuum chamber 204, and a second relationship indicating the thermal transition between a second temperature different from the first temperature measured by the temperature sensor 203, the second pressure value measured by the vacuum sensor 201, and the diameter and the pressure in the vacuum chamber 204.

[0033] For example, the thermal transition correction circuit 206 controls the heater 211 to heat the inside of the sensor container 202, causing the vacuum sensor 201 to reach a first temperature T1, and in this state, obtains a first pressure value p1 measured by the vacuum sensor 201. Because the pipe diameter d of the pressure introduction pipe 205 is known, a first relationship indicating the thermal transition between the first temperature T1 measured by the temperature sensor 203, the first pressure value p1 measured at this time, and the pipe diameter d can be obtained from the first temperature T1 measured by the temperature sensor 203, the first pressure value p1 measured at this time, and the pipe diameter d, as shown in equation (1).

[0034] Furthermore, the thermal transition correction circuit 206 obtains a second temperature T2 of the vacuum sensor 201 measured by the temperature sensor 203 while the inside of the sensor container 202 is heated by controlling the heater 211, and a second pressure value p2 measured by the vacuum sensor 201 at this time. For example, the first pressure value p1 and the second pressure value p2 can be measured at different times.

[0035] Since the pipe diameter d of the pressure introduction pipe 205 is known, a second relationship showing the thermal transition between the second pressure value p2 measured at the second temperature T2 and the pipe diameter d and the pressure p0 in the vacuum chamber 204, as shown in equation (2), can be obtained.

[0036] By solving the simultaneous equations of the relational expression (1) between p0 and p1, which represents the first relationship, and the relational expression (2) between p0 and p2, which represents the second relationship, it is possible to obtain equation (3) for calculating the pressure p0 inside the vacuum chamber 204. The thermal transpiration correction circuit 206 can calculate the pressure p0 inside the vacuum chamber 204 using equation (3). The thermal transpiration correction circuit 206 outputs the calculated pressure p0 as a pressure measurement value from a vacuum gauge. Note that equation (3) for calculating the pressure p0 inside the vacuum chamber 204 can be calculated in advance, and the calculated equation (3) can be set in the thermal transpiration correction circuit 206.

[0037] Furthermore, by solving the simultaneous equations of relational expressions (1) and (2), it is possible to obtain equation (4) for calculating the temperature T0 inside the vacuum chamber 204. The thermal transition correction circuit 206 can calculate the temperature T0 inside the vacuum chamber 204 using equation (4). The thermal transition correction circuit 206 can output the calculated temperature T0.

[0038] Furthermore, the thermal transition correction circuit 206 calculates p0 by varying T0 in relational expressions (1) and (2), and can find the solution of T0 and p0 when the difference between p0 is smallest (mathematical optimization program).

[0039] As described above, according to an embodiment of the present invention, the pressure inside the vacuum chamber is determined from a first relationship between the first temperature of the first vacuum sensor and the first pressure value measured by the first vacuum sensor, and a second relationship between the second temperature of the second vacuum sensor and the second pressure value measured by the second vacuum sensor, thereby making it possible to suppress measurement errors in the vacuum gauge due to thermal transition phenomena.

[0040] It should be noted that the present invention is not limited to the embodiments described above, and it is clear that many modifications and combinations can be made by a person having ordinary knowledge in the art within the technical concept of the present invention. [Explanation of symbols]

[0041] 101...first vacuum sensor, 102...first sensor container, 103...second vacuum sensor, 104...second sensor container, 105...first temperature sensor, 106...second temperature sensor, 107...vacuum chamber, 108...first pressure introduction pipe, 109...second pressure introduction pipe, 110...thermal transition compensation circuit, 111...common introduction pipe, 112...heater, 113...heater, 201...vacuum sensor, 202...sensor container, 203...vacuum chamber, 204...pressure introduction pipe, 205...thermal transition compensation circuit, 211...heater.

Claims

1. a first sensor container that houses a first vacuum sensor; a second sensor container containing a second vacuum sensor; a first temperature sensor for measuring a temperature of the first vacuum sensor; a second temperature sensor for measuring the temperature of the second vacuum sensor; a first pressure introduction pipe that introduces the pressure of a medium to be measured in a vacuum chamber that is a pressure measurement target to the first sensor container; a second pressure introduction pipe that introduces the pressure of the medium to be measured in the vacuum chamber to the second sensor container; a thermal transition correction circuit configured to determine the pressure inside the vacuum chamber from a first relationship indicating thermal transition between a first temperature measured by the first temperature sensor, a first pressure value measured by the first vacuum sensor, and a diameter of the first pressure introduction pipe and the pressure inside the vacuum chamber, and from a second relationship indicating thermal transition between a second temperature measured by the second temperature sensor, a second pressure value measured by the second vacuum sensor, and a diameter of the second pressure introduction pipe and the pressure inside the vacuum chamber; A vacuum gauge comprising:

2. 2. The vacuum gauge of claim 1, A vacuum gauge in which the first pressure introduction pipe and the second pressure introduction pipe have different pipe diameters.

3. a first sensor container that houses a first vacuum sensor; a second sensor container containing a second vacuum sensor; a first temperature sensor for measuring a temperature of the first vacuum sensor; a second temperature sensor for measuring the temperature of the second vacuum sensor; a first pressure introduction pipe that introduces the pressure of a medium to be measured in a vacuum chamber that is a pressure measurement target to the first sensor container; a second pressure introduction pipe having a different diameter from the first pressure introduction pipe for introducing the pressure of the medium to be measured in the vacuum chamber to the second sensor container; a thermal transition correction circuit configured to determine the pressure inside the vacuum chamber from a first relationship indicating thermal transition between the first temperature measured by the first temperature sensor, the first pressure value measured by the first vacuum sensor, and the diameter of the first pressure introduction pipe and the pressure inside the vacuum chamber, and a second relationship indicating thermal transition between the second temperature measured by the second temperature sensor, the second pressure value measured by the second vacuum sensor, and the diameter of the second pressure introduction pipe and the pressure inside the vacuum chamber; A vacuum gauge comprising:

4. a sensor container that houses a vacuum sensor; a temperature sensor for measuring the temperature of the vacuum sensor; a pressure introduction pipe for introducing the pressure of a medium to be measured in a vacuum chamber of a pressure measurement target to the sensor container; a thermal transition correction circuit configured to determine the pressure inside the vacuum chamber from a first relationship indicating thermal transition between a first temperature measured by the temperature sensor, a first pressure value measured by the vacuum sensor, and a pipe diameter of the pressure introduction pipe and the pressure inside the vacuum chamber, and from a second relationship indicating thermal transition between a second temperature different from the first temperature measured by the temperature sensor, a second pressure value measured by the vacuum sensor, and the pipe diameter and the pressure inside the vacuum chamber; A vacuum gauge comprising:

5. 5. The vacuum gauge according to claim 4, A vacuum gauge in which the first pressure value and the second pressure value are measured at different times.

Images