JP2016180650A - Calibration device and calibration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a plurality of calibration objects to be calibrated with the same quality of calibration.SOLUTION: The need for the calibration of a calibration object pressure sensor 120 is determined on the basis of a difference ΔSp between a measurement output signal Sc obtained when a fluid FL of reference pressure Pr to be measured that is reproduced on the basis of a reference output signal Spr stored in an initial state storage unit 101 acts upon the diaphragm of the calibration object pressure sensor 120 and the reference output signal Spr. When it is determined that the calibration object pressure sensor 120 needs to be calibrated, it is possible to calibrate the calibration object pressure sensor 120 on the basis of output signals Sr, Sr' from a calibration reference pressure sensor 110, and, therefore, it is possible to calibrate a plurality of calibration objects by one calibration reference pressure sensor 110 with the same quality of calibration.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a calibration device and a calibration system, and more particularly, to a calibration device and a calibration system for calibrating a capacitance-type pressure sensor that detects a change in a diaphragm that is bent under the pressure of a fluid to be measured as a change in capacitance. .

  Conventionally, for example, in a thin film forming process in a semiconductor manufacturing apparatus or the like, a diaphragm vacuum gauge is used to measure the pressure in a vacuum state.

  This diaphragm vacuum gauge has a diaphragm that isolates the pressure introduction part of the fluid to be measured and the reference vacuum chamber, and is measured from the displacement of the diaphragm that is elastically deformed by the differential pressure between the pressure of the fluid to be measured and the pressure of the reference air chamber. It is a pressure gauge that measures the pressure of fluid.

  For example, Patent Document 1 discloses a pressure sensor in which a sensor unit is accommodated in a housing having a pressure introducing portion for a fluid to be measured (see Patent Document 1). In this pressure sensor, the sensor unit includes a diaphragm that isolates the pressure introducing portion of the fluid to be measured and the reference vacuum chamber, a movable electrode provided in the diaphragm, and a fixed electrode that is disposed opposite to the movable electrode. And.

  A pressure sensor having such a sensor unit detects displacement of a diaphragm that is elastically deformed according to the pressure of a fluid to be measured as a change in capacitance between the movable electrode and the fixed electrode. Also called a sensor.

  When such a diaphragm vacuum gauge is used in the thin film forming process, the material of the thin film substance to be processed, its by-products, etc. are deposited on the surface of the diaphragm on the pressure introduction side of the fluid to be measured. Hereinafter, a deposit such as a material of a thin film substance and a by-product deposited on the surface of the diaphragm or a film made of the deposit is simply referred to as a “deposit”.

  By depositing deposits on only one surface of the diaphragm in this way, the balance of force in the thickness direction of the diaphragm is lost, and in fact, even when there is no pressure difference on both sides of the diaphragm, the surface of the diaphragm is It will bend. Further, the Young's modulus of the diaphragm as a diaphragm that separates the pressure introducing portion of the fluid to be measured and the reference vacuum chamber changes due to the influence of the deposit.

  Due to the influence of this deposit, the measurement value of the diaphragm vacuum gauge will cause an error. Therefore, especially for the diaphragm vacuum gauge used in the thin film formation process, it is periodically calibrated using another standard vacuum gauge. Need to do.

  Regarding the calibration of the diaphragm vacuum gauge, an integrated vacuum gauge has been proposed in which a vacuum gauge to be calibrated and a vacuum gauge to be calibrated are integrated (see, for example, Patent Document 2).

JP 2012-207986 A JP-A-5-346364

  However, when the integrated vacuum gauge described in Patent Document 2 is used as a plurality of vacuum gauges attached to a single semiconductor manufacturing apparatus, the plurality of integrated vacuum gauges each serve as a reference for its own calibration. Since calibration is performed using this method, there is a problem that the quality of calibration is not uniform. This is because there are variations in the characteristics of the vacuum gauges that serve as the calibration reference for each of the plurality of integrated vacuum gauges.

  The present invention is intended to solve such a problem, and an object of the present invention is to provide a calibration apparatus and a calibration system that calibrate a plurality of calibration objects with a certain quality.

  In order to achieve this object, the present invention provides a plurality of pressure sensors (120) that output an electrical signal in accordance with the displacement of the diaphragm when subjected to the pressure of the fluid to be measured (FL). A calibration device (100) for calibrating using a reference pressure sensor (110), comprising a diaphragm of a calibration reference pressure sensor (110) serving as a calibration reference or a diaphragm of a calibration target pressure sensor (120) serving as a calibration target. An initial state storage unit (101) for storing a reference output signal (Spr) obtained when a fluid to be measured (FL) having a predetermined reference pressure (Pr) acts, and stored in the initial state storage unit (101). When the fluid to be measured (FL) of the reference pressure (Pr) reproduced based on the reference output signal (Spr) acts on the diaphragm of the calibration target pressure sensor (120) The difference (ΔSp) between the obtained measurement output signal (Sc) and the reference output signal (Spr) is compared with a predetermined threshold (th1) to determine whether or not the calibration target pressure sensor (120) needs to be calibrated. When the calibration necessity determination unit (102) and the calibration necessity determination unit (102) determine that the calibration is necessary, output signals (Sr, Sr ′) from the calibration reference pressure sensor (110) And a calibration processing unit (105) for calibrating the calibration target pressure sensor (120) based on the above.

  In the present invention, the calibration processing unit (105) uses the calibration reference pressure sensor (120) as a relational expression representing a relationship between a physical quantity detected according to the displacement of the diaphragm and the measurement output signal (Sc). The relational expression correcting unit (103) that corrects the output using the output signals (Sr, Sr ′) and the relational expression corrected by the relational expression correcting part (103) are output to the calibration target pressure sensor (120). Output unit (104).

  In the present invention, the calibration reference pressure sensor (110) and the plurality of calibration target pressure sensors (120) include a plurality of branch pipes branched from a main pipe (2) supplied with the fluid to be measured (FL). 2a, 2b, and 2c) and a branch valve (V1) is installed in the branch pipe (2a) connected to the calibration reference pressure sensor (110).

  In the present invention, the plurality of calibration target pressure sensors (120, 130) are supplied with different systems of fluids to be measured (FL1, FL2) respectively corresponding to the plurality of calibration target pressure sensors (120, 130). The calibration reference pressure sensor (110) is connected to the ends of the branch pipes (3a, 4a) branched from the plurality of main pipes (3, 4), respectively. In addition to being connected, gate valves (V2, V3) are respectively installed in the plurality of branch pipes (3a, 4a).

  In the present invention, whether or not it is time to perform a calibration process based on the accumulated usage time of the calibration target pressure sensor (120) or the pressure value indicated by the measurement output signal (Sc) of the calibration target pressure sensor (120). And a calibration time determination unit (106) for determining the above.

  In the present invention, a plurality of calibration target pressure sensors (120) to be calibrated for outputting an electrical signal corresponding to the displacement of the diaphragm when the pressure (P) of the fluid to be measured (FL) is received by the diaphragm; One calibration reference pressure sensor (110) serving as a calibration reference, and a fluid to be measured having a predetermined reference pressure (Pr) on the diaphragm of the calibration reference pressure sensor (110) or the diaphragm of the calibration target pressure sensor (120) The initial state storage unit (101) for storing the reference output signal (Spr) obtained when the (FL) is actuated, and the reproduction based on the reference output signal (Spr) stored in the initial state storage unit (101) The measured output signal (F) obtained when the fluid to be measured (FL) having the reference pressure (Pr) acts on the diaphragm of the calibration target pressure sensor (120). c) and a difference (ΔSp) between the reference output signal (Spr) and a predetermined threshold (th1) to determine whether or not the calibration target pressure sensor (120) needs to be calibrated. (102) and the calibration necessity determination unit (102) determines that the calibration is necessary, the calibration is performed based on the output signals (Sr, Sr ′) from the calibration reference pressure sensor (110). A calibration processing unit (105) for calibrating the target pressure sensor (120).

  According to the present invention, the fluid to be measured (FL) of the reference pressure (Pr) reproduced based on the reference output signal (Spr) stored in the initial state storage unit (101) is the diaphragm of the calibration target pressure sensor (120). The calibration target pressure sensor (120) is determined based on the difference (ΔSp) between the measurement output signal (Sc) and the reference output signal (Spr) obtained when acting on the calibration target pressure sensor. When it is determined that it is necessary to calibrate (120), the calibration target pressure sensor (120) can be calibrated based on the output signals (Sr, Sr ′) from the calibration reference pressure sensor (110). A plurality of calibration objects can be calibrated with the same calibration quality by one calibration reference pressure sensor (110).

  According to the present invention, not only a plurality of calibration target pressure sensors (120, 130) connected to the main pipe (2) of the same system, but also a plurality of fluids to be measured (FL1, FL2) of different systems are supplied. Since a plurality of calibration target pressure sensors (150, 160) connected to the main pipe (3, 4) can also be calibrated using only one calibration reference pressure sensor (110), a plurality of calibration targets are selected. Calibration can be performed with the same calibration quality.

It is a system instrumentation figure which shows the connection state of the one reference | standard calibration diaphragm vacuum gauge in 1st Embodiment, the several calibration object diaphragm vacuum gauge, and a calibration apparatus. It is a block diagram which shows the structure of the calibration apparatus in 1st Embodiment. It is a system instrumentation figure which shows the connection state of the one reference | standard calibration diaphragm vacuum gauge in 2nd Embodiment, the several calibration object diaphragm vacuum gauge, and a calibration apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
<Overall configuration of calibration system>
As shown in FIG. 1, a calibration system 1 according to the first embodiment includes one diaphragm vacuum gauge (hereinafter referred to as a “calibration reference diaphragm vacuum gauge”) 110 serving as a calibration reference, and calibration. A plurality of diaphragm vacuum gauges (hereinafter referred to as “calibration target diaphragm vacuum gauges”) 120 and 130 and a calibration device 100 are provided. Note that the number of diaphragm vacuum gauges 120 and 130 to be calibrated is not limited to two.

  A main pipe 2 to which a fluid to be measured FL is supplied is connected to the calibration reference diaphragm vacuum gauge 110 and the calibration target diaphragm vacuum gauges 120 and 130. The main pipe 2 is branched into branch pipes 2a, 2b, and 2c having the same number as the total number of calibration reference diaphragm vacuum gauges 110 and calibration target diaphragm vacuum gauges 120 and 130.

  A calibration reference diaphragm vacuum gauge 110 is connected to the end of the branch pipe 2a, and a valve V1 for partitioning the inflow of the fluid FL to be measured is set in the branch pipe 2a. In addition, calibration target diaphragm vacuum gauges 120 and 130 are connected to the ends of the branch pipes 2b and 2c.

  The calibration reference diaphragm vacuum gauge 110 and the calibration target diaphragm vacuum gauges 120 and 130 are diaphragm vacuum gauges having the same basic function and performance. As for the diaphragm vacuum gauges 120 and 130 to be calibrated, if the pressure P of the fluid FL to be measured of the same system is measured, the pressure ranges to be measured are different from each other, or the measurement resolutions are different from each other. It may be.

  Here, the calibration reference diaphragm vacuum gauge 110 and the calibration target diaphragm vacuum gauges 120 and 130 are diaphragm vacuum gauges having the same structure, and the structure thereof will be described by taking the calibration target diaphragm vacuum gauge 120 as an example.

  The calibration target diaphragm vacuum gauge 120 includes a calibration target sensor unit 120s and a sensor output calculation unit 120c. The calibration target sensor unit 120s includes a diaphragm that isolates the pressure introducing portion of the fluid FL to be measured and the reference vacuum chamber, a movable electrode provided in the diaphragm, and a fixed electrode that is spaced from the movable electrode and opposed to the movable electrode. It has.

  The sensor unit 120s to be calibrated uses the displacement of the diaphragm that is elastically deformed by the pressure difference between the pressure P of the fluid FL to be measured and the pressure of the reference air chamber as a change in the capacitance C between the movable electrode and the fixed electrode. The capacitance C is detected and output to the sensor output calculation unit 120c.

The sensor output calculation unit 120c measures the pressure P of the fluid FL to be measured based on the value of the capacitance C. Here, the relational expression between the capacitance C and the pressure P of the fluid to be measured can be expressed by a linear expression such as the following (Expression 1), and the sensor output calculation unit 120c Held in memory. Here, a and b are coefficients (parameters) for obtaining the pressure P based on the capacitance C.
P = a × C + b ………………………………………………………………………… (Formula 1)

  The configurations of the calibration reference diaphragm vacuum gauge 110 and the calibration target diaphragm vacuum gauge 130 are the same as those of the calibration target diaphragm vacuum gauge 120, and are provided with a calibration reference sensor unit 110r, a calibration target sensor unit 130s, and sensor output calculation units 110c and 130c. It has been.

<Configuration of calibration device>
The calibration apparatus 100 includes an initial state storage unit 101, a calibration necessity determination unit 102, a calibration processing unit 105, and a calibration time determination unit 106.

  The calibration apparatus 100 is realized by installing a computer program (software) in a computer (hardware) including a CPU (Central Processing Unit), a memory, an interface, and the like. This is realized by cooperation between various hardware resources and a computer program.

  The initial state storage unit 101 stores a pressure value corresponding to the sensor output signal Sr0 obtained when the fluid FL to be measured having the reference pressure Pr is supplied to the calibration reference diaphragm vacuum gauge 110 as an initial value. have.

  The initial state storage unit 101 corresponds to a sensor output signal Sc0 obtained when the fluid FL to be measured having the reference pressure Pr is supplied to the calibration target diaphragm vacuum gauge 120 in the initial state before the start of use or immediately after the calibration process. The calibration target storage unit 101b stores the pressure value to be stored as an initial value. The sensor output signal Sr0 and the sensor output signal Sc0 are collectively referred to as a reference output signal Spr.

  Incidentally, the initial state storage unit 101 sets initial values of the sensor output signal of the calibration reference diaphragm vacuum gauge 110 and the sensor output signal of the calibration target diaphragm vacuum gauge 120 corresponding to another reference pressure Pr ′ larger or smaller than the reference pressure Pr. Can be stored respectively.

  The calibration necessity determination unit 102 determines whether or not calibration is required for the calibration target sensor unit 120s, and includes a comparison unit and a holding unit.

For example, the comparison unit reproduces the state in which the fluid FL to be measured having the reference pressure Pr is supplied so that the sensor output signal Sr0 stored in the calibration reference storage unit 101a as the initial value is detected by the calibration reference diaphragm vacuum gauge 110. The sensor output signal Sc obtained by the diaphragm vacuum gauge 120 before calibration after being used for an arbitrary time, and the reference output signal Spr (sensor output signal Sro or Sco) stored in the initial state storage unit 101. The difference ΔSp is calculated by the following (Expression 2), and the difference ΔSp is compared with the threshold value th1. The holding unit holds a threshold value th1 to be compared.
ΔSp = Sc−Spr …………………………………………………………………… (Formula 2)

  When the difference ΔSp calculated by the comparison unit and the threshold value th1 are compared with the threshold value th1, the calibration necessity determination unit 102 determines that the diaphragm vacuum gauge 120 to be calibrated needs to be calibrated. The calibration command is output to the calibration processing unit 103.

  Note that the calibration necessity determination unit 102 receives the sensor output signal of the calibration reference diaphragm vacuum gauge 110 and the sensor output signal of the calibration target diaphragm vacuum gauge 120 corresponding to the reference pressure Pr ′ in addition to the reference pressure Pr as described above. When stored as initial values, differences ΔSp and ΔSp ′ corresponding to a plurality of reference pressures Pr and Pr ′ are obtained, and calibration of the diaphragm vacuum gauge 120 to be calibrated is performed based on the differences ΔSp and ΔSp ′ of both. It is possible to determine whether or not it is necessary.

  The calibration processing unit 105 includes a relational expression correcting unit 103 and an output unit 104. The relational expression correcting unit 103 uses the sensor output signal Sr obtained by the calibration reference diaphragm vacuum gauge 110 to output the sensor output signal Sc output from the calibration target diaphragm vacuum gauge 120 after being used for an arbitrary time and before calibration. The coefficients (parameters) a and b of the relational expression of (Expression 1) representing the measurement pressure P corresponding to are corrected.

  The output unit 104 outputs a new relational expression represented by the coefficients (parameters) a and b corrected by the relational expression correction unit 103 to the sensor output calculation unit 120c of the calibration target diaphragm vacuum gauge 120. The relational expression of the measured pressure P corresponding to the sensor output signal Sc held in advance in the internal memory of the sensor output calculation unit 120c is updated with a new relational expression.

  The calibration time determination unit 105 determines the timing at which the calibration target diaphragm vacuum gauge 120 before calibration after use for an arbitrary time is calibrated. The calibration time determination unit 105 includes an internal memory that stores a predetermined reference pressure value Pb for determining whether or not the calibration time has come.

  The calibration time determination unit 105 detects that the pressure value of the sensor output signal Sc received from the calibration target diaphragm vacuum gauge 120 matches the reference pressure value Pb stored in the internal memory of the calibration time determination unit 105. At this time, it is recognized that the calibration time has come, and a signal indicating this is output to an external notification device (not shown).

  Here, the notification device performs some notification to the operator based on the signal received from the calibration time determination unit 105. Here, the notification device is, for example, a warning sound generating unit or a warning lamp lighting unit. However, the present invention is not limited to this, and various other means may be used.

<Calibration operation>
Next, a series of calibration operations until the calibration target diaphragm vacuum gauge 120 is calibrated after being used for an arbitrary time by the calibration apparatus 100 is divided into an initial state storage stage, a calibration necessity judgment stage, and a calibration processing stage. I will explain.

≪Initial state storage stage≫
First, the operator opens the valve V1 of the branch pipe 2a connected to the calibration reference diaphragm vacuum gauge 110. In this state, the operator operates the pressure P of the fluid FL to be measured, and the pressure value corresponding to the sensor output signal Sc0 that is the pressure measurement result of the fluid FL to be measured measured by the diaphragm vacuum gauge 120 to be calibrated is specified in advance. Is set to the initial state where the reference pressure Spr is set (eg, 0 [Pa]). Here, the semiconductor manufacturing apparatus is provided with a pressure adjusting mechanism for adjusting the pressure P of the fluid to be measured FL, and the operator uses the pressure adjusting mechanism to change the pressure P of the fluid to be measured FL to the reference pressure Spr. It may be adjusted so that

  In the initial state where the pressure value corresponding to the sensor output signal Sc0 of the fluid FL to be measured measured by the calibration target diaphragm vacuum gauge 120 becomes the reference pressure Pr, the sensor output signal Sr0 measured by the calibration reference diaphragm vacuum gauge 110 is obtained. The corresponding pressure value is stored in the calibration reference storage unit 101a as an initial value.

  In the same pressure state, the pressure value corresponding to the sensor output signal Sc0 measured by the calibration target diaphragm gauge 120 is stored in the calibration target storage unit 101b as an initial value.

  Here, the pressure value corresponding to the sensor output signal Sc0 of the calibration target diaphragm vacuum gauge 120 is different from the place where the calibration reference diaphragm vacuum gauge 110 is installed, for some reason such as the difference in how to take the reference pressure, There may be a slight pressure difference that is not the same as the pressure value corresponding to the sensor output signal Sr0 of the calibration reference diaphragm gauge 110.

This slight pressure difference is not an error and is constant between the pressure value corresponding to the sensor output signal Sc0 of the calibration target diaphragm vacuum gauge 120 and the pressure value corresponding to the sensor output signal Sr0 of the calibration reference diaphragm vacuum gauge 110. It is considered that there is a proportional relationship in which there is a difference between the two, and both can be expressed by the following (formula 3). By grasping the slight pressure difference in advance as described above, there is a deviation in the sensor output value between the sensor output signal Sr of the calibration reference diaphragm vacuum gauge 110 and the sensor output signal Sc of the calibration target diaphragm vacuum gauge 120. Even in this case, the calibration process can be executed. This pressure difference is stored in the calibration target storage unit 101b.
Sr0∝Sc0 …………………………………………………………………………… (Formula 3)

≪Calibration necessity judgment stage≫
First, the calibration time determination unit 105 of the calibration apparatus 100 determines that the pressure value of the sensor output signal Sc when the pressure P of the fluid FL to be measured is measured by the calibration target diaphragm vacuum gauge 120 after the initial state storage stage is When it is detected that the reference pressure value Pb (for example, 0 [Pa]) stored in the internal memory of the calibration time determination unit 105 coincides, it is recognized that the calibration time has come, and a signal indicating this is sent to an external notification device. (Not shown). Here, the reference pressure value Pb means that calibration is always performed when the pressure P of the fluid FL to be measured measured by the diaphragm vacuum gauge 120 to be calibrated matches the pressure value Pb in the process of the semiconductor manufacturing apparatus, for example. It is a preset pressure value.

  The notification device outputs, for example, a buzzer sound based on a signal from the calibration time determination unit 105. By checking the buzzer sound, the operator recognizes that a predetermined calibration processing timing has come.

  The operator who has confirmed the buzzer sound opens the valve V1 of the branch pipe 2a connected to the calibration reference diaphragm vacuum gauge 110. In this state, the operator operates the pressure P of the fluid to be measured FL, and the pressure value of the sensor output signal Sr of the fluid to be measured FL measured by the calibration reference diaphragm vacuum gauge 110 is stored in advance in the calibration reference storage unit 101a. The pressure value (initial value) of the sensor output signal Sr0 in the initial state storage stage is set. As a result, it is possible to reproduce the initial state in which the fluid to be measured FL having the reference pressure Pr set in the initial state storage stage is supplied from the main pipe 2. In this case as well, the pressure P of the fluid FL to be measured is adjusted using the pressure adjustment mechanism of the semiconductor manufacturing apparatus.

  Incidentally, when there is no necessity for calibration in the calibration target diaphragm vacuum gauge 120, that is, the pressure value of the sensor output signal Sc of the calibration target diaphragm vacuum gauge 120 is stored in the calibration target storage unit 101b. When the initial value of the sensor output signal Sc0 of the meter 120 remains unchanged, the same pressure value as the reference pressure Pr is measured from the calibration target sensor unit 120s.

  After that, the calibration necessity determination unit 102 reproduces the initial state in which the fluid to be measured FL having the reference pressure Pr is supplied to the main pipe 2, and then the calibration target diaphragm vacuum gauge 120 s before calibration after use for an arbitrary time. The sensor output signal Sc obtained by measuring the fluid to be measured FL at the reference pressure Pr is acquired.

  Further, the calibration necessity determination unit 102 reads the sensor output signal Sr0 of the calibration reference diaphragm vacuum gauge 110 stored in the calibration reference storage unit 101a in the initial state storage stage. The calibration necessity determination unit 102 calculates the difference ΔSp between the sensor output signal Sc and the sensor output signal Sr0 according to (Equation 2) described above.

  The calibration necessity determination unit 102 obtains the difference ΔSp by (Equation 2), but stores the sensor output signal Sc of the calibration target diaphragm vacuum gauge 120 and the calibration target storage unit 101b in the initial state storage stage. A difference from the previously described sensor output signal Sc0 may be obtained.

  When it is recognized that the difference ΔSp represented by (Equation 2) exceeds the predetermined threshold th1, the calibration necessity determination unit 102 performs a calibration necessity determination that it is necessary to calibrate the diaphragm vacuum gauge 120 to be calibrated. The calibration processing command is output to the relational expression correcting unit 103 of the calibration processing unit 105. When the calibration necessity determination unit 102 recognizes that the difference ΔSp does not exceed the threshold th1, the calibration necessity determination unit 102 determines that the calibration target diaphragm vacuum gauge 120 does not need to be calibrated, and outputs a calibration processing command. There is no.

≪Calibration process stage≫
By the way, there is an error α between the sensor output signal Sc of the diaphragm vacuum gauge 120 to be calibrated, which is the result of measuring the fluid FL to be measured at the pressure P, and the true value P of the pressure corresponding to the sensor output signal Sc. In this case, the true value P is expressed by the following (Expression 4) using (Expression 3) described above. Here, Sr∝Sc0, α = Sc-Sc0.
P = Sr = Sc−α ……………………………………………… (Formula 4)

Here, “Sc0” is the sensor output signal of the diaphragm vacuum gauge 120 to be calibrated in the initial state, and is expressed by the following (Equation 5). “Sc” is a sensor output signal of the calibration target diaphragm vacuum gauge 120 before calibration in the calibration required state, and is expressed by the following (formula 6).
Sc0 = a0 × C0 + b0 ……………………………………………………………… (Formula 5)
Sc = a0 × C1 + b0 ……………………………………………………………… (Formula 6)

Here, a0, b0, a1, and b1 are coefficients (parameters) constituting the relational expressions of (Expression 5) and (Expression 6). C0 is a capacitance value (capacitance) of a capacitor formed by the fixed electrode and the movable electrode of the calibration target sensor unit 120s of the calibration target diaphragm gauge 120 in the initial state. Similarly, C1 is a capacitance value (capacitance) of a capacitor composed of a fixed electrode and a movable electrode of the calibration target sensor unit 120s after an error occurs in the sensor output signal Sc of the calibration target diaphragm gauge 120. is there. Therefore, the error factor ΔC is expressed by the following (Equation 7).
ΔC = C1-C0 ………………………………………………………………………… (Formula 7)

  As shown in (Equation 6), the sensor output signal Sc of the calibration target diaphragm vacuum gauge 120 before calibration is determined by the coefficients a0 and b0. If an error occurs in the sensor output signal Sc, These coefficients a0 and b0 cannot be used. Therefore, it is necessary to obtain new coefficients (parameters) a1 and b1 by a calculation method to be described later, and update the coefficients a0 and b0 in (Equation 6) to the coefficients a1 and b1.

In this case, the relational expression correcting unit 103 uses the sensor output signals Sr and Sr ′ of the calibration reference sensor unit 110r corresponding to the reference pressure Pr and the pressure P ′, respectively, according to the following (Expression 8) and (Expression 9). What is necessary is just to obtain | require the coefficient a1.
P′−Pr = Sr′−Sr = (a1 × C1 ′ + b1) − (a1 × C1 + b1)
= A1 × (C1′−C1) ………………………………………………………… (Formula 8)
a1 = (Sr′−Sr) / (C1′−C1) ………………………………………… (Formula 9)

Further, when the reference pressure Pr is set to 0 [Pa] as a vacuum pressure, the following (Expression 10) is established.
Pr = 0 = Sr∝Sc (= Sc0) …………………………………………… (Formula 10)

By substituting the value of a1 according to (Equation 9) and the value of Sc according to (Equation 10) into (Equation 6), the value of the coefficient b1 can be obtained. The calibration processing unit 105 replaces the coefficients a1 and b1 obtained in this way with the coefficients a0 and b0 expressed by (Equation 5), and the sensor output signal Sc of the calibration target diaphragm vacuum gauge 120 after the calibration process. A new relational expression represented by the following (Expression 11) can be obtained.
Sc = a1 × C0 + b1 ……………………………………………………………… (Formula 11)

  The output unit 104 of the calibration processing unit 105 calculates a sensor output of the calibration target diaphragm vacuum gauge 120 based on a new relational expression such as (Expression 11) that represents the sensor output signal Sc of the calibration target diaphragm vacuum gauge 120 after the calibration process. The relational expression of (Expression 5) transmitted to the unit 120c and stored in the internal memory is updated by replacing it with the relational expression of (Expression 11). Thereby, the calibration process of the sensor output signal of the diaphragm vacuum gauge 120 to be calibrated is completed.

  The output unit 104 does not transmit the new relational expression represented by (Equation 11) to the sensor output calculation unit 120c of the calibration target diaphragm vacuum gauge 120, but only the coefficients a1 and b1 of the calibration target diaphragm vacuum gauge 120. You may make it transmit to the sensor output calculation part 120c, and make it replace with the coefficients a0 and b0.

<Effect>
The calibration apparatus 100 uses the calibration reference diaphragm vacuum gauge 110 to perform a calibration process similar to the calibration process for the calibration target diaphragm vacuum gauge 120 on the other calibration target diaphragm vacuum gauges 130, thereby providing a single calibration apparatus 100. Therefore, the plurality of calibration target diaphragm vacuum gauges 120 and 130 can be calibrated, so that the quality of calibration for the plurality of calibration target diaphragm vacuum gauges 120 and 130 can be made uniform.

  Further, since the calibration apparatus 100 is not integrated with the calibration target diaphragm vacuum gauges 120 and 130 but separate, the calibration apparatus 100 is prepared in the vicinity of the calibration target diaphragm vacuum gauges 120 and 130 provided in the semiconductor manufacturing apparatus. Thus, the diaphragms 120 and 130 to be calibrated can be calibrated with the same calibration quality without being removed from the semiconductor manufacturing apparatus. Thereby, since it is not necessary to remove the calibration subject diaphragm vacuum gauges 120 and 130, downtime for stopping the semiconductor manufacturing apparatus can be reduced even when performing the calibration process.

<Second Embodiment>
<Overall configuration of calibration system>
As shown in FIG. 3, the calibration system 200 according to the second embodiment is a calibration reference diaphragm vacuum gauge 110 that serves as a calibration reference and a calibration target, as in the first embodiment. A plurality of calibration object diaphragm vacuum gauges 150 and 160 and a calibration apparatus 100 are provided. In the second embodiment, the same reference numerals are used for the calibration device 100 and the calibration reference diaphragm vacuum gauge 110 shown in FIG. 1, and detailed descriptions thereof are omitted.

  Here, the calibration reference diaphragm vacuum gauge 110 and the calibration target diaphragm vacuum gauges 150 and 160 are diaphragm vacuum gauges having the same basic function and performance. However, the diaphragm vacuum gauges 150 and 160 to be calibrated may be the same diaphragm vacuum gauge, or may be diaphragm vacuum gauges having different ranges, resolutions, functions, and the like.

  The diaphragm to be calibrated 150 is connected to the end of the main pipe 3 to which the fluid to be measured FL1 having the pressure PA is supplied. The diaphragm to be calibrated 160 is connected to the end of the main pipe 4 to which the fluid to be measured FL2 having the pressure PB is supplied. The main pipes 3 and 4 are pressure guiding pipes of different systems that supply different pressures and types of fluids to be measured FL1 and FL2.

  The calibration reference diaphragm vacuum gauge 110 is connected to both the main pipe 3 to which the fluid to be measured FL1 is supplied and the main pipe 4 to which the fluid to be measured FL2 is supplied. The main pipe 3 has a branch pipe 3 a branched in the middle of the pipe, and the main pipe 4 has a branch pipe 4 a branched in the middle of the pipe, similarly to the main pipe 3.

  The branch pipes 3a and 4a are joined at their tips, and a common pipe 5 for connecting the fluid to be measured FL1 or FL2 to the calibration reference diaphragm vacuum gauge 110 is connected to the joint. A calibration reference diaphragm vacuum gauge 110 is connected to the end of the common pipe 5. The branch pipes 3a and 4a do not necessarily have to be joined to each other at the ends, and the ends of the branch pipes 3a and 4a may be connected to the calibration reference diaphragm vacuum gauge 110, respectively.

  The branch pipe 3a is provided with a valve V2 for partitioning the inflow of the fluid to be measured FL1. The branch pipe 4a is provided with a valve V3 that partitions the inflow of the fluid to be measured FL2. The valve V2 is used so that the valve V3 is closed when the valve V3 is opened, and the valve V3 is closed when the valve V2 is opened.

  The calibration reference diaphragm vacuum gauge 110 has the same configuration as that of the first embodiment. Further, the calibration target diaphragm vacuum gauge 150 is provided with a calibration target sensor unit 150s that detects the displacement of the diaphragm that is bent by receiving the pressure PA of the fluid FL1 to be measured as a change in the capacitance C. Similarly, the calibration target diaphragm vacuum gauge 160 is provided with a calibration target sensor unit 160s that detects the displacement of the diaphragm that receives the pressure PB of the fluid FL2 to be measured as a change in the capacitance C.

  The sensor output calculation units 150c and 160c are connected to the calibration target sensor units 150s and 160s of the calibration target diaphragm vacuum gauges 150 and 160 in the same manner as the calibration target diaphragm vacuum gauges 120 and 130 in the first embodiment. ing. The sensor output calculation units 150c and 160c generate a sensor output signal Sc indicating the measured pressure P of the fluid FL to be measured based on the capacitance C of the calibration target sensor units 150s and 160s. The sensor output signal Sc Is stored in the internal memory.

  The calibration reference diaphragm gauge 110 outputs the sensor output signal Sr generated by the sensor output calculation unit 110c to the calibration device 100. The diaphragm vacuum gauges 150 and 160 to be calibrated output the sensor output signal Sc generated by the sensor output calculators 150 c and 160 c to the calibration device 100.

  In this case, when calibrating the diaphragm vacuum gauges 150 and 160 to be calibrated, the calibration apparatus 100 divides into the initial state storage stage, the calibration necessity judgment stage, and the calibration processing stage in the same manner as in the first embodiment. Although the operation is performed, when calibrating the diaphragm vacuum gauge 150 to be calibrated, the valve V2 is opened but the valve V3 is set to be closed. When calibrating the diaphragm vacuum gauge 160 to be calibrated, the valve V3 is opened. However, the valve V2 is set in a closed state.

  Thereby, the calibration process for the calibration subject diaphragm vacuum gauges 150 and 160 for measuring the two systems of fluids to be measured FL1 and FL2 can be alternately performed by only one calibration reference diaphragm vacuum gauge 110. Thus, also in the calibration system 200, the calibration quality of a plurality of calibration target diaphragm vacuum gauges 150 and 160 connected to the main pipes 3 and 4 of different systems can be made uniform with only one calibration reference diaphragm vacuum gauge 110, respectively. it can.

<Other embodiments>
In the embodiment described above, the coefficients a1 and b1 are obtained using the sensor output signals Sr and Sr ′ of the calibration reference diaphragm vacuum gauge 110 corresponding to the two points of the reference pressure Pr and the pressure P ′, respectively. Although the case has been described, the present invention is not limited to this, and the number of application points of the pressure of the fluid to be measured FL applied to the main pipe 2 may be increased such as three points, four points,. In this case, the coefficient can be obtained using a higher order expression, and the diaphragm for vacuum membrane 120 to be calibrated can be calibrated with higher accuracy.

  In the embodiment described above, the calibration time determination unit 106 confirms that the pressure value of the sensor output signal Sc received from the sensor output calculation unit 120c matches the reference pressure value Pb stored in the internal memory. A case has been described in which, when detected, it is recognized that the calibration time has come, and a signal indicating the calibration time is output to an external notification device (not shown). However, the present invention is not limited to this, and the accumulated use time from the unused state of the diaphragm vacuum gauge 120 to be calibrated or immediately after the calibration process is measured in the calibration time determination unit 106, and when the accumulated use time is reached. It is determined that it is the calibration time, and is output to an external notification device (not shown), and a signal indicating that is output to the calibration necessity determination unit 102, and the calibration necessity determination unit 102 is triggered by the signal. It may be determined whether or not it is necessary to calibrate the diaphragm vacuum gauge 120 to be calibrated.

  DESCRIPTION OF SYMBOLS 1 ... Calibration system 2, 3, 4 ... Main piping, 110 ... Calibration standard diaphragm gauge (calibration standard pressure sensor), 110r ... Calibration standard sensor unit, 120, 130, 150, 160 ... Calibration object Diaphragm vacuum gauge (calibration target pressure sensor), 120 s, 130 s, 150 s, 160 s ... calibration target sensor unit, 100... Calibration device, 101... Initial state storage unit, 102. Relational expression correction unit 104... Output unit 105... Calibration processing unit 106.

Claims (6)

A calibration device that calibrates a plurality of pressure sensors that output an electrical signal corresponding to the displacement of a diaphragm when the pressure of a fluid to be measured is received using another one pressure sensor,
An initial state storage unit for storing a reference output signal obtained when a fluid to be measured having a predetermined reference pressure acts on a diaphragm of a calibration reference pressure sensor serving as a calibration reference or a diaphragm of a calibration target pressure sensor serving as a calibration target; ,
The measurement output signal obtained when the fluid under measurement having the reference pressure reproduced based on the reference output signal stored in the initial state storage unit acts on the diaphragm of the calibration target pressure sensor, and the reference output signal. A calibration necessity determination unit that compares the difference with a predetermined threshold and determines whether calibration is required for the calibration target pressure sensor;
A calibration processing unit configured to calibrate the calibration target pressure sensor based on an output signal from the calibration reference pressure sensor when the calibration is determined to be necessary by the calibration necessity determination unit. Calibration device. The calibration processing unit corrects a relational expression representing a relationship between a physical quantity detected according to the displacement of the diaphragm and the measurement output signal by using the output signal of the calibration reference pressure sensor. When,
The calibration apparatus according to claim 1, further comprising: an output unit that outputs the relational expression modified by the relational expression modification unit to the calibration target pressure sensor. The calibration reference pressure sensor and the plurality of calibration target pressure sensors are connected to ends of a plurality of branch pipes branched from a main pipe to which the fluid to be measured is supplied, and are connected to the calibration reference pressure sensors. The calibrating device according to claim 1, further comprising: a gate valve installed on the branch pipe. The plurality of calibration target pressure sensors are respectively connected to the ends of a plurality of main pipes to which fluids to be measured of different systems corresponding to the plurality of calibration target pressure sensors are respectively supplied.
The calibration reference pressure sensor is connected to an end of a branch pipe branched from each of the plurality of main pipes,
The calibration apparatus according to claim 1, wherein a gate valve is installed in each of the plurality of branch pipes. A calibration time determination unit that determines whether or not it is time to perform a calibration process based on the accumulated usage time of the calibration target pressure sensor or the pressure value indicated by the measurement output signal of the calibration target pressure sensor. The calibration apparatus according to claim 2, wherein the calibration apparatus is characterized in that: A plurality of calibration target pressure sensors to be calibrated for outputting an electrical signal corresponding to the displacement of the diaphragm when the pressure of the fluid to be measured is received by the diaphragm;
One calibration reference pressure sensor that serves as a reference for calibration;
An initial state storage unit that stores a reference output signal obtained when a fluid to be measured having a predetermined reference pressure acts on the diaphragm of the calibration reference pressure sensor or the diaphragm of the calibration target pressure sensor;
A measurement output signal obtained when the fluid under measurement having the reference pressure reproduced based on the reference output signal stored in the initial state storage unit acts on a diaphragm of the pressure sensor to be calibrated, and the first reference output signal; A calibration necessity determining unit that compares the difference between the pressure sensor and a predetermined threshold value to determine whether the calibration target pressure sensor needs to be calibrated,
A calibration processing unit that calibrates the calibration target pressure sensor based on the reference output signal from the calibration reference pressure sensor when the calibration is determined to be necessary by the calibration necessity determination unit. Calibration system.

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