Diaphragm vacuum gauge

Abstract

To automatically switch a self heating temperature.SOLUTION: A diaphragm gauge comprises: a pressure receiving unit 10 whose electrical characteristics change according to displacement of a diaphragm due to the pressure of a medium to be measured; a heater 5 that heats the pressure receiving unit 10; a temperature sensor 9 that measures the temperature of the pressure receiving unit 10; a pressure measuring unit 13 that converts the change in electrical characteristics of the pressure receiving unit 10 into a measured pressure value; a temperature setting unit 14 that sets a heating temperature set value according to the measured pressure value; and a heater control unit 16 that controls power supplied to the heater 5 based on the temperature measured by the temperature sensor 9 and the heating temperature set value.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] A diaphragm vacuum gauge is used for measuring the pressure of a semiconductor process chamber. If the temperature of the semiconductor process gas is not appropriate, it will liquefy or solidify and adhere to the sensor part of the diaphragm vacuum gauge, affecting the measurement. Therefore, the diaphragm vacuum gauge has a self-heating function to prevent the adhesion of liquefied or solidified process gas (see Patent Document 1, Patent Document 2, Patent Document 3).

[0003] On the other hand, in recent years, semiconductor processes have become more advanced, and various gases are used in one process. Since the appropriate self-heating temperature may vary depending on the process gas, there is also a diaphragm vacuum gauge having a function of switching the self-heating temperature like the diaphragm vacuum gauges disclosed in Patent Document 2 and Patent Document 3. Furthermore, when the diaphragm vacuum gauge is not in use, there are some that have a function of turning off the self-heating function to reduce power consumption.

[0004] However, in the conventional diaphragm vacuum gauge, there is a problem that a switching signal has to be input from the outside to the diaphragm vacuum gauge in order to switch the self-heating temperature.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a diaphragm vacuum gauge capable of automatically switching the self-heating temperature.

Means for Solving the Problems

[0007] The diaphragm vacuum gauge of the present invention includes a pressure receiving portion configured such that its electrical characteristics change according to the displacement of a diaphragm due to the pressure of a medium to be measured, a heater configured to heat the pressure receiving portion, a temperature sensor configured to measure the temperature of the pressure receiving portion, a pressure measurement portion configured to convert a change in the electrical characteristics of the pressure receiving portion into a measured pressure value, a temperature setting portion configured to set a heating temperature setting value according to the measured pressure value obtained by the pressure measurement portion, and a heater control portion configured to control the power supplied to the heater based on the temperature measured by the temperature sensor and the heating temperature setting value. 、 A storage portion configured to store the measured pressure value and the heating temperature setting value in association with each other. comprising Further, the temperature setting portion is characterized in that it acquires a heating temperature setting value corresponding to the measured pressure value obtained by the pressure measurement portion from the storage portion.

[0008] Also, in one configuration example of the diaphragm vacuum gauge of the present invention, the storage portion further stores a pressure increase automatic setting invalidation flag and a pressure decrease automatic setting invalidation flag, and the temperature setting portion invalidates the switching of the heating temperature setting value when the measured pressure value increases when the pressure increase automatic setting invalidation flag is in a set state, and invalidates the switching of the heating temperature setting value when the measured pressure value decreases when the pressure decrease automatic setting invalidation flag is in a set state. Also, in one configuration example of the diaphragm vacuum gauge of the present invention, the storage portion further stores a delay time until the heating temperature setting value is switched, and the temperature setting portion switches the heating temperature setting value after the elapse of the delay time when switching the heating temperature setting value. Also, in one configuration example of the diaphragm vacuum gauge of the present invention, the storage unit stores, as the delay time, a pressure increase delay time and a pressure decrease delay time, and when the temperature setting unit switches the heating temperature setting value when the measured pressure value increases, the heating temperature setting value is switched after the elapse of the pressure increase delay time, and when the heating temperature setting value is switched when the measured pressure value decreases, the heating temperature setting value is switched after the elapse of the pressure decrease delay time.

[0009] Further, one configuration example of the diaphragm vacuum gauge of the present invention is characterized by further comprising a setting change unit capable of changing the stored content of the storage unit in response to an instruction from the outside. Further, one configuration example of the diaphragm vacuum gauge of the present invention is characterized by further comprising a notification unit configured to notify the outside of the heating temperature setting value. Further, one configuration example of the diaphragm vacuum gauge of the present invention is characterized by further comprising a notification unit configured to notify the outside that the self-heating temperature of the diaphragm vacuum gauge has reached the heating temperature setting value when the temperature measured by the temperature sensor reaches the heating temperature setting value.

Effects of the Invention

[0010] According to the present invention, by providing a temperature setting unit that sets the heating temperature setting value according to the measured pressure value, the self-heating temperature of the diaphragm vacuum gauge can be automatically switched, and an external signal for switching the self-heating temperature is not required, so that the production of hardware for generating the switching signal of the self-heating temperature is not required.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a diaphragm vacuum gauge according to an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of a main part of a sensor chip used in the diaphragm vacuum gauge.

[0013] The diaphragm vacuum gauge includes a pressure receiving part 10 in which the capacitance (electrical characteristic) changes according to the displacement of a diaphragm (diaphragm) due to the pressure of a medium to be measured (for example, a process gas), and a circuit part 11 that converts the change in the capacitance of the pressure receiving part 10 into a measured pressure value.

[0014] The sensor chip 1 of the pressure receiving part 10 includes a diaphragm constituent member 100 and a pedestal 101. The diaphragm constituent member 100 includes a diaphragm 102 configured to be deformable according to the pressure P of a medium to be measured (for example, a process gas), and a diaphragm support part 103 formed thicker than the diaphragm 102 to support the peripheral part of the diaphragm 102 so as not to be displaced. The pedestal 101 is joined to the diaphragm support part 103 and forms a reference vacuum chamber 104 together with the diaphragm 102.

[0015] In the sensor chip 1, a fixed electrode 105 is formed on the surface of the pedestal 101 on the reference vacuum chamber 104 side, and a movable electrode 106 is formed on the surface of the diaphragm 102 on the reference vacuum chamber 104 side so as to face the fixed electrode 105. When the diaphragm 102 bends under the pressure P of the medium to be measured, the distance between the movable electrode 106 and the fixed electrode 105 changes, and the capacitance between the movable electrode 106 and the fixed electrode 105 changes. The pressure P of the medium to be measured received by the diaphragm 102 can be detected from this change in capacitance. The diaphragm component 100 and the pedestal 101 are made of an insulator such as sapphire, for example.

[0016] The diaphragm vacuum gauge shown in FIG. 1 includes the sensor chip 1 configured as described above, a housing 2 that houses the sensor chip 1, a pressure introduction pipe 3 that guides the pressure P of the medium to be measured to the diaphragm 102 of the sensor chip 1, a sensor case 4 that covers the housing 2, and a heater 5 provided so as to surround the outer peripheral surface of the sensor case 4. The sensor case 4 provided with the heater 5 is covered with a heat insulating material 6.

[0017] A partition wall 7 is provided inside the housing 2. The partition wall 7 is composed of a pedestal plate 7a and a support plate 7b, and separates the internal space of the housing 2 into a first space 2a and a second space 2b. The outer periphery of the support plate 7b is fixed to the housing 2, and the pedestal plate 7a is supported in a state of floating in the internal space of the housing 2. The sensor chip 1 is fixed to the second space 2b side of the pedestal plate 7a. Further, a pressure introduction hole 7c for guiding the pressure in the first space 2a to the diaphragm 102 of the sensor chip 1 is formed in the pedestal plate 7a. The second space 2b communicates with the reference vacuum chamber 104 of the sensor chip 1 and is in a vacuum state.

[0018] The pressure introduction pipe 3 is connected to the first space 2a side of the housing 2. A baffle 8 is provided between the pressure introduction pipe 3 and the housing 2. The medium to be measured introduced from the pressure introduction pipe 3 hits the plate surface of the baffle 8 and flows into the first space 2a of the housing 2 through the gaps around the baffle 8. A temperature sensor 9 is provided on the outer wall surface of the housing 2. The temperature sensor 9 measures the temperature of the housing 2 as the temperature of the pressure-receiving part 10.

[0019] The circuit part 11 of the diaphragm vacuum gauge is composed of a capacitance detection part 12, a pressure measurement part 13, a temperature setting part 14, a memory part 15, a heater control part 16, a notification part 17, and a setting change part 18.

[0020] Next, the operation of this embodiment will be described. FIG. 3 is a flowchart for explaining the operation of the diaphragm vacuum gauge of this embodiment. The capacitance detection part 12 detects a change in the capacitance (electrical characteristic) between the movable electrode 106 and the fixed electrode 105 due to the displacement of the diaphragm 102 of the pressure-receiving part 10 (step S100 in FIG. 3).

[0021] The pressure measurement part 13 converts the change in capacitance detected by the capacitance detection part 12 into a measured pressure value MP and outputs it (step S101 in FIG. 3). The temperature setting part 14 sets a heating temperature setting value tsp according to the measured pressure value MP obtained by the pressure measurement part 13 (step S102 in FIG. 3).

[0022] The memory part 15 stores the measured pressure value MP and the heating temperature setting value tsp in association with each other. The temperature setting part 14 acquires the heating temperature setting value tsp corresponding to the measured pressure value MP from the memory part 15. The parameter consisting of the set of the measured pressure value MP and the corresponding heating temperature setting value tsp can be freely changed by the user from outside the diaphragm vacuum gauge.

[0023] The temperature detection part 19 acquires the value of the temperature tpv measured by the temperature sensor 9. The heater control part 16 controls the power supplied to the heater 5 so that the temperature tpv measured by the temperature sensor 9 matches the heating temperature setting value tsp (step S103 in FIG. 3). The notification part 17 notifies the outside, that is, the user, of the current heating temperature setting value tsp by displaying it (step S104 in FIG. 3).

[0024] Further, when the temperature tpv measured by the temperature sensor 9 reaches the heating temperature set value tsp (YES in step S105 of FIG. 3), the notification unit 17 notifies the user that the self-heating temperature of the diaphragm vacuum gauge has reached the heating temperature set value tsp, for example, by displaying a message indicating that the self-heating temperature has reached the heating temperature set value tsp or lighting an LED or the like (step S106 of FIG. 3).

[0025] Until the pressure measurement operation ends according to an instruction from the outside, for example, an instruction from the user (YES in step S107 of FIG. 3), the diaphragm vacuum gauge performs the processes of steps S100 to S106 at regular intervals.

[0026] Thus, in this embodiment, the self-heating temperature of the diaphragm vacuum gauge can be automatically switched, and an external signal for switching the self-heating temperature becomes unnecessary.

[0027] In addition, when the temperature setting unit 14 switches the heating temperature set value tsp due to the measured pressure value MP exceeding a certain range, a delay time may be provided until the heating temperature set value tsp is switched so that the heating temperature set value tsp does not switch immediately. This delay time can also be registered in advance in the storage unit 15 as a parameter.

[0028] The delay time may be invalid when the measured pressure value MP is rising, but may be valid only when the measured pressure value MP is falling. That is, there are a pressure rise delay time and a pressure fall delay time as the delay time. When the pressure rise delay time is set, the temperature setting unit 14 switches the heating temperature set value tsp after the elapse of the pressure rise delay time when switching the heating temperature set value tsp during the rise of the measured pressure value MP. Further, when the pressure fall delay time is set, the temperature setting unit 14 switches the heating temperature set value tsp after the elapse of the pressure fall delay time when switching the heating temperature set value tsp during the fall of the measured pressure value MP.

[0029] In addition, in the storage unit 15, a parameter such as a flag for invalidating the automatic setting of the heating temperature setting value tsp when the measured pressure value MP rises and a flag for invalidating the automatic setting of the heating temperature setting value tsp when the measured pressure value MP falls can be registered in advance in the storage unit 15. When the pressure increase automatic setting invalidation flag is in the set state, the temperature setting unit 14 invalidates the switching of the heating temperature setting value tsp when the measured pressure value MP rises. Further, when the pressure decrease automatic setting invalidation flag is in the set state, the temperature setting unit 14 invalidates the switching of the heating temperature setting value tsp when the measured pressure value MP falls.

[0030] The setting change unit 18 can change the parameters stored in the storage unit 15 from the outside, that is, in response to an instruction from the user.

[0031] FIG. 4 is a diagram showing an example of the parameters stored in the storage unit 15, and FIG. 5 is a diagram showing an example of the switching operation of the self-heating temperature. As shown in FIG. 4, in the storage unit 15, the range of the measured pressure value MP, the heating temperature setting value tsp, the delay time when the pressure rises, the delay time when the pressure falls, the pressure increase automatic setting invalidation flag, and the pressure decrease automatic setting invalidation flag are stored as parameters.

[0032] In the example of FIG. 4, since the delay time when the pressure rises is not set, when switching the heating temperature setting value tsp when the measured pressure value MP rises, the switching is performed immediately. On the other hand, since the delay time Tdown when the pressure falls is set, when switching the heating temperature setting value tsp when the measured pressure value MP falls, the switching is performed after waiting for Tdown. Since both the pressure increase automatic setting invalidation flag and the pressure decrease automatic setting invalidation flag are "RESET", the heating temperature setting value tsp is automatically set both when the measured pressure value MP rises and falls. To invalidate the automatic setting, the invalidation flag may be set to "SET".

[0033] Also, in the range where MP < SP1, SP3 ≤ MP, the heating temperature set value tsp is "OFF". In the case of "OFF", the heater control unit 16 does not supply power to the heater 5. Note that, for the sake of easy understanding of the state transition in FIG. 5, the process state is described in FIG. 4, but the process state in FIG. 4 is not a parameter stored in the storage unit 15.

[0034] Next, the switching operation of the self-heating temperature based on the setting in FIG. 4 will be described with reference to FIG. 5. The example in FIG. 5 shows an example in which the diaphragm vacuum gauge of the present embodiment is used for measuring the pressure in a semiconductor process chamber. First, an inert gas such as N2 is introduced into the process chamber in a vacuum state, and the measured pressure value MP increases. When the measured pressure value MP is less than the set value SP1, the temperature setting unit 14 sets the heating temperature set value tsp to "OFF". Therefore, the heater control unit 16 does not supply power to the heater 5.

[0035] When the measured pressure value MP further rises and becomes equal to or greater than the set value SP1, the temperature setting unit 14 sets the heating temperature set value tsp to 200 °C. Since no pressure rise delay time is set here, the switching of the heating temperature set value tsp is performed immediately. Then, the heater control unit 16 controls the power supplied to the heater 5 so that the temperature tpv measured by the temperature sensor 9 coincides with the heating temperature set value tsp = 200 °C.

[0036] Next, process gas A is introduced into the process chamber. After the film formation process using process gas A is performed, an inert gas such as N2 is introduced into the process chamber, and the measured pressure value MP further rises. When the measured pressure value MP becomes equal to or greater than the set value SP2 (SP1 < SP2), the temperature setting unit 14 sets the heating temperature set value tsp to 50 °C. Similar to the above, since no pressure rise delay time is set, the switching of the heating temperature set value tsp is performed immediately. Then, the heater control unit 16 controls the power supplied to the heater 5 so that the temperature tpv measured by the temperature sensor 9 coincides with the heating temperature set value tsp = 50 °C.

[0037] Subsequently, process gas B is introduced into the process chamber. After the film formation process using process gas B is performed, an inert gas such as N2 is introduced into the process chamber, and the measured pressure value MP further increases. When the measured pressure value MP becomes equal to or higher than the set value SP3 (SP2 < SP3), the temperature setting unit 14 sets the heating temperature set value tsp to "OFF". Similarly to the above, since no pressure increase delay time is set, the switching of the heating temperature set value tsp is immediately performed. Then, due to the heating temperature set value tsp becoming "OFF", the heater control unit 16 does not supply power to the heater 5.

[0038] Next, evacuation of the process chamber is started, and the measured pressure value MP decreases. At this time, since the pressure decrease delay time Tdown is set, the heating temperature set value tsp remains "OFF". That is, when the measured pressure value MP becomes less than the set value SP3, the heating temperature set value tsp should be switched to 50°C, but the measured pressure value MP becomes less than the set value SP2 before the pressure decrease delay time Tdown elapses. When the measured pressure value MP becomes less than the set value SP2, the heating temperature set value tsp should be switched to 200°C, but the measured pressure value MP becomes less than the set value SP1 before the pressure decrease delay time Tdown elapses. Therefore, in any case, the switching of the heating temperature set value tsp is not performed.

[0039] In this way, in this embodiment, an optimal heating temperature set value tsp can be set according to the process gas. Also, when self-heating is not required, the power consumption can be reduced by stopping the power supply to the heater 5.

[0040] In this embodiment, a capacitance-type diaphragm vacuum gauge in which the capacitance changes according to the displacement of the diaphragm has been described, but the present invention is not limited to this, and the present invention may be applied to other types of diaphragm vacuum gauges. As an example of another type of diaphragm vacuum gauge, for example, there is a piezoresistive diaphragm vacuum gauge that uses a semiconductor silicon formed with a diffusion resistor as a diaphragm and converts the resistance change of the resistor according to the displacement of the diaphragm into a measured pressure value.

[0041] The circuit unit 11 described in this embodiment can be realized by a computer including a CPU (Central Processing Unit), a storage device, and an interface, and a program for controlling these hardware resources. A configuration example of this computer is shown in FIG. 6.

[0042] The computer includes a CPU 200, a storage device 201, and an interface device (I / F) 202. Connected to the I / F 202 are the hardware part of the capacitance detection unit 12, the hardware part of the heater control unit 16, the hardware part of the notification unit 17, the hardware part of the setting change unit 18, and the like. In such a computer, a program for realizing the method of the present invention is stored in the storage device 201. The CPU 200 executes the processing described in this embodiment according to the program stored in the storage device 201.

Industrial Applicability

[0043] The present invention can be applied to a diaphragm vacuum gauge.

Explanation of Signs

[0044] 1... sensor chip, 5... heater, 9... temperature sensor, 10... pressure receiving part, 11... circuit unit, 12... capacitance detection unit, 13... pressure measurement unit, 14... temperature setting unit, 15... storage unit, 16... heater control unit, 17... notification unit, 18... setting change unit, 19... temperature detection unit, 102... diaphragm, 105... fixed electrode, 106... movable electrode.

Claims

1. A pressure-receiving part configured such that its electrical characteristics change according to the displacement of a diaphragm due to the pressure of a medium to be measured; A heater configured to heat the pressure-receiving part; A temperature sensor configured to measure the temperature of the pressure-receiving part; A pressure measurement part configured to convert the change in the electrical characteristics of the pressure-receiving part into a measured pressure value; A temperature setting part configured to set a heating temperature set value according to the measured pressure value obtained by the pressure measurement part; A heater control part configured to control the power supplied to the heater based on the temperature measured by the temperature sensor and the heating temperature set value; A storage part configured to store the measured pressure value and the heating temperature set value in association with each other; and The temperature setting part is characterized in that it acquires, from the storage part, a heating temperature set value corresponding to the measured pressure value obtained by the pressure measurement part. A diaphragm vacuum gauge.

2. In the diaphragm vacuum gauge according to Claim 1, The storage part further stores a pressure increase automatic setting invalidation flag and a pressure decrease automatic setting invalidation flag, The temperature setting part invalidates the switching of the heating temperature set value when the measured pressure value increases when the pressure increase automatic setting invalidation flag is in a set state, and invalidates the switching of the heating temperature set value when the measured pressure value decreases when the pressure decrease automatic setting invalidation flag is in a set state. A diaphragm vacuum gauge characterized by this.

3. In the diaphragm vacuum gauge according to Claim 1 or 2, The storage part further stores a delay time until the heating temperature set value is switched, The temperature setting part is characterized in that when switching the heating temperature set value, it switches the heating temperature set value after the elapse of the delay time. A diaphragm vacuum gauge.

4. In the diaphragm vacuum gauge according to Claim 3, The storage part stores, as the delay time, a pressure increase delay time and a pressure decrease delay time, When switching the heating temperature set value when the measured pressure value increases, the temperature setting part switches the heating temperature set value after the elapse of the pressure increase delay time, and when switching the heating temperature set value when the measured pressure value decreases, the temperature setting part switches the heating temperature set value after the elapse of the pressure decrease delay time. A diaphragm vacuum gauge characterized by this.

5. In the diaphragm vacuum gauge according to any one of Claims 1 to 4, A diaphragm vacuum gauge, further comprising a setting change unit capable of changing the stored content of the storage unit according to an external instruction.

6. In the diaphragm vacuum gauge according to any one of claims 1 to 5, A diaphragm vacuum gauge, further comprising a notification unit configured to notify the external heating temperature set value.

7. In the diaphragm vacuum gauge according to any one of claims 1 to 5, When the temperature measured by the temperature sensor reaches the heating temperature set value, the diaphragm vacuum gauge further comprises a notification unit configured to notify the outside that the self-heating temperature of the diaphragm vacuum gauge has reached the heating temperature set value. A diaphragm vacuum gauge characterized by that.

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