JP5874193B2 - Flow control device and flow sensor unit - Google Patents

Description

  The present invention relates to a flow rate control device for supplying a fluid having a controlled flow rate to a predetermined facility.

  A mass flow controller used in a semiconductor manufacturing process controls a flow control valve provided in a fluid passage based on an output of a flow sensor that detects a flow rate of a fluid flowing through the fluid passage. The fluid passage is branched into a bypass flow path that constitutes a main flow path and a sensor flow path that is a secondary flow path at a portion where the flow sensor is provided. More fluid flows in the bypass channel than in the sensor channel. In the range of the flow rate that can be controlled by the mass flow controller, the flow rate of the gas flowing through the bypass flow channel and the flow rate of the gas flowing through the sensor flow channel maintain a constant ratio.

  A pair of resistance wires connected in series with each other are wound around the upstream and downstream sides of the surface of the pipe constituting the sensor flow path. These resistance wires are made of a material whose resistivity changes with a temperature change. These resistance wires have the same resistance value at the same temperature. When these resistance wires are energized to generate heat, the gas flowing through the sensor flow path first takes heat away from the upstream resistance. The gas heated by the upstream resistance flows downstream and gives the heat to the downstream resistance wire, or from the downstream resistance wire, the gas is heated as much as the upstream resistance wire. Not take away. As a result, a temperature difference occurs between the two resistance wires. Then, a difference arises in the resistance value of two resistance wires. This difference in resistance value appears as a difference between the potential difference between both ends of the upstream resistance wire and the potential difference between both ends of the downstream resistance wire. The magnitude of this difference in potential difference is substantially proportional to the mass flow rate of the gas flowing through the sensor tube. Further, as described above, the flow rate of the gas flowing through the bypass flow path and the flow rate of the gas flowing through the sensor flow path maintain a constant ratio. For this reason, the magnitude of the difference between the potential difference between both ends of the upstream resistance wire and the potential difference between both ends of the downstream resistance wire is substantially proportional to the flow rate of the fluid flowing through the entire fluid passage. The flow sensor outputs a signal proportional to the difference in potential difference as a signal representing the flow rate of the fluid flowing through the entire fluid passage.

In a semiconductor manufacturing process, a gas whose mass flow rate is controlled by a mass flow controller is supplied to a semiconductor manufacturing facility. In such a semiconductor manufacturing process, the same raw material fluid may be supplied in a small flow rate range or in a larger flow rate range. For example, a film forming gas that is a raw material fluid may be used at a flow rate of about 100 ccm (cm ³ / min) in the preliminary process, and may be used at a flow rate of about 10 ccm in the subsequent process.

  The error range of the flow rate control of the mass flow controller operating on the principle as described above is generally set within plus or minus several percent (for example, around plus or minus 5%) with respect to the full scale. For this reason, in a mass flow controller designed with a full scale of 100 ccm, a flow error of plus or minus 5 ccm is allowed. When such a mass flow controller is used to control a minute flow rate of about 10 ccm, a flow rate error of about plus or minus 5 ccm can occur even in a flow rate region of 10 ccm. Such an error corresponds to 50% of the target flow rate. Therefore, if a mass flow controller designed with a full scale of 100 ccm is used in a flow rate region of 10 ccm, the influence of errors cannot be ignored.

  The technique of Patent Document 1 includes two gain circuits for enlarging the difference in potential difference caused by the temperature difference between the resistance wires. The first gain circuit is a gain circuit for use in flow control of a full scale of 100 ccm. The second gain circuit is a gain circuit for use in flow control of a full scale of 10 ccm. If each gain circuit is set so that the flow rate control error range of the mass flow controller is about several percent, the two gain circuits are switched according to the target flow rate, thereby reducing the low flow rate range and the high flow rate range. Highly accurate flow rate control can be performed in the flow rate range.

  In the technique of Patent Document 2, two secondary flow paths around which resistance wires are wound are provided. The two secondary channels branch off from the primary channel at approximately the same location in the flow direction. The secondary flow path A joins a primary flow path as a main flow path downstream of the secondary flow path B. As a result, the secondary channel A has a longer channel length than the secondary channel B. Further, by changing the inner diameter of the two secondary channels or providing a “flow restricting element” in at least one of the two secondary channels, the flow rate of the fluid flowing in the two secondary channels, In other words, the ratio of the flow rate of the fluid flowing in each secondary flow channel to the flow rate of the primary flow channel as the main flow channel is made different. These two secondary channels are used to detect flow rates for different flow ranges.

JP 2001-142541 A Special Table 2000-507706

  In the flow sensor based on the principle as described above, when the flow rate of the fluid passing through the fluid passage reaches a predetermined value or more, the temperature difference between the two resistance wires is not proportional to the flow rate. The speed at which the pipes constituting the secondary flow channel transfer heat cannot catch up with the speed of the fluid flowing in the fluid passage, and (i) the fluid passing through the fluid passage gives heat to the downstream resistance wire. (Ii) because the temperature of the fluid does not increase because heat is not taken away from the upstream resistance wire, and heat is also taken away from the downstream resistance wire. It is. As a result, of the pipes constituting the sensor flow path, the portion with the highest temperature is further downstream than the position where the downstream resistance wire is wound, and the upstream resistance wire and the downstream resistance wire are Temperature difference does not increase. As a result, the temperature difference between the two resistance wires is not proportional to the flow rate. The technique of Patent Document 1 considers the operation error but does not consider the above point. For this reason, the technique of Patent Document 1 cannot increase the flow rate range in which the flow rate can be accurately measured and controlled to a range with a higher flow rate.

  In the technique of Patent Document 2, the inner diameters of the two secondary flow paths are changed, or “flow restricting elements” are provided in at least one of them. In such an embodiment, when the pressure upstream of the primary and secondary channels changes, the ratio of the flow rate of the secondary channel to the flow rate of the primary channel is not kept constant. That is, the accuracy of the flow sensor cannot be maintained over a wide flow range.

  Further, as in the technique of Patent Document 2, two secondary flow paths used for different flow ranges have different lengths along the flow direction of the primary flow path. In other words, when the range of the flow rate to be controlled in the facility changes, the dimension of the space required for the flow direction of the primary flow path changes. Generally, the range in which a mass flow controller can be installed in a manufacturing facility for semiconductors or the like is limited in advance. For this reason, such an aspect is not realistic as a mass flow controller installed in a manufacturing facility.

  The problem of the flow rate range to be detected and the problem of the installation space of the flow control device described above exist not only in the mass flow meter used in the semiconductor manufacturing process, but also in various fluid flow control devices.

  The present invention has been made in order to deal with at least a part of the above-described problems, and realizes a flow rate control in a small flow rate range and a flow rate control in a larger flow rate range with high accuracy and a realistic space. It aims at realizing the flow control device which can be installed inside.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A flow rate control device for controlling a flow rate of a fluid flowing in a fluid passage,
A fluid passage for flowing fluid;
A flow rate control valve unit for controlling the flow rate of the fluid flowing through the fluid passage;
A flow rate sensor unit for detecting a flow rate of the fluid flowing through the fluid passage;
A controller that controls the flow rate control valve unit based on the output of the flow rate sensor unit,
The fluid passage is
A bypass flow path that constitutes the fluid passage in part along the direction of flow of the fluid;
A part of the fluid that flows through the fluid passage and before flowing through the bypass passage is branched, and then the part of the fluid joins the fluid that has passed through the bypass passage. 1 and a second sensor flow path, wherein the second sensor flow path is equal to the first sensor flow path and the flow path is longer than the first sensor flow path. A first sensor flow path and a second sensor flow path,
The flow sensor unit, for each sensor flow path,
An upstream resistor (heating unit) for heating the fluid flowing in the sensor flow path;
A downstream resistor (temperature changing portion) that is provided downstream of the upstream resistor and changes in temperature by a fluid flowing in the sensor flow path;
An output unit that outputs a signal corresponding to a difference in resistance value between the upstream resistor and the downstream resistor;
The first and second sensor flow paths have the same distance along the flow direction of the fluid passage from the point where the part of the fluid is branched to the point where the part of the fluid is joined. Configured as
The flow rate sensor unit and the control unit include the signal based on the difference in the resistance value of the first sensor flow path and the second sensor flow path according to the size of the target flow rate of the fluid. The flow rate control device configured to be able to control the flow rate control valve unit by properly using the signal based on the difference in resistance value.

  In such an embodiment, the second channel has the same channel cross section as the first channel, and the channel is long. For this reason, when the conditions on the branch side are the same, the flow rate of the fluid flowing in the second flow path per unit time is the flow rate of the fluid flowing in the first flow path per unit time. Compared to less. Therefore, the temperature of the downstream resistor provided in the second flow path is higher than the temperature of the downstream resistor provided in the first flow path. However, the flow rate change can be reflected better. As a result, when the target flow rate is in a small range, the flow control valve unit is controlled with high accuracy based on the output based on the difference between the resistance values of the two resistors provided in the first sensor flow path. When the flow rate is in a large range, the flow control valve unit can be controlled with high accuracy based on the output based on the difference between the resistance values of the two resistors provided in the second sensor flow path.

  In addition, the first and second sensor flow paths are distances along the direction of fluid flow in the fluid path from the point where the fluid is branched to the point where the fluid is branched, even though the lengths of the flow paths are different. Are equal to each other. For this reason, even if the length of the flow path of the first and second sensor flow paths is set according to the flow rate range required for the fluid to be controlled, it follows the direction of fluid flow in the fluid path. The size of the space they need does not change. Therefore, the flow control device can be installed in a predetermined space.

Therefore, if it is set as the above aspects, a flow control device that can realize flow control in a small flow range and flow control in a larger flow range with high accuracy and can be installed in a realistic space. Can be realized.
In the above aspect, the “fluid” may be a gas or a liquid.
Also, three or more sensor flow paths can be provided. A plurality of sets of sensor flow path groups having the same flow path cross section may be provided.

[Application Example 2]
It is a flow control device of application example 1,
The bypass control device is a flow rate control device configured by a plurality of partial channels each having a channel cross section equal to a channel cross section of the first and second channels.

  With such an aspect, the ratio between the flow rate of the fluid flowing through the bypass flow path and the flow rate of the fluid flowing through the first and second flow paths is constant over a wide flow rate range of the fluid flowing through the fluid passage. Can keep. Therefore, the flow rate can be controlled by accurately detecting the flow rate over a wide flow range of the fluid flowing through the fluid passage.

[Application Example 3]
A flow control device according to application example 1 or 2,
The members constituting the range in which the upstream resistor and the downstream resistor are provided in the second sensor channel are the upstream resistor and the member in the first sensor channel. A flow rate control device made of a material having a higher thermal conductivity than that of a member constituting a range in which a downstream resistor is provided.

  According to such an aspect, even if the flow velocity of the fluid flowing in the second sensor flow path is increased, the downstream resistor provided in the second sensor flow path reflects the temperature of the fluid. Cheap. Therefore, even if the flow rate of the fluid flowing through the entire fluid passage increases, the flow rate sensor unit uses the upstream resistor and the downstream resistor of the second sensor flow path to accurately detect the fluid flow rate. Can be detected.

  In general, a material having a high thermal conductivity is expensive. However, in the said aspect, the part in which the upstream resistor and downstream resistor of the 1st sensor flow path are provided is not comprised with a raw material with high heat conductivity. For this reason, the cost of the whole flow sensor unit and flow control device can be reduced. The upstream resistor and the downstream resistor provided in the first sensor flow path are used when the target flow rate is in a small range. For this reason, the downstream resistor sufficiently reflects the temperature of the fluid even if the upstream resistor and the downstream resistor of the second sensor flow path are not made of a material having high thermal conductivity. be able to.

[Application Example 4]
A flow control device according to any one of Application Examples 1 to 3,
The point at which the first sensor flow path branches the part of the fluid and the point at which the second sensor flow path branches the part of the fluid are in the flow direction of the fluid passage. In the same position,
The first sensor flow path joins the part of the fluid to the fluid flowing through the bypass flow path, and the second sensor flow path to the fluid that flows through the bypass flow path. The point of joining the fluids is a flow rate control device that is at the same position in the flow direction of the fluid passage.

  With such an aspect, even if the lengths of the first and second sensor flow paths are set in accordance with the flow range of the fluid to be controlled, the direction of the fluid flow in the fluid path is maintained. The size of the space they need does not change. Then, as compared with an aspect in which the branch point and the merge point of the first sensor flow path are shifted from the branch point and the merge point of the second sensor flow path, the flow direction of the fluid in the fluid passage is aligned. Thus, the size of the space required for the first and second sensor flow paths can be reduced.

[Application Example 5]
It is a flow control device of application example 4,
The member constituting at least a part of the first sensor channel has a channel cross section equal to that of the first sensor channel in the fluid passage. What is the first sensor channel? It is provided to be exchangeable with a member that can constitute at least a part of the third sensor flow path having a different flow path length.
The member constituting at least a part of the second sensor channel has a channel cross section equal to the second sensor channel in the fluid path. A flow rate control device provided to be replaceable with a member that can constitute at least a part of a fourth sensor flow channel having a different flow channel length.

  With such an aspect, the first and second sensor flow paths can be replaced with the third and fourth sensor flow paths in accordance with the flow range of the fluid to be controlled. And even if it replaces the member which comprises the flow path for sensors according to the flow range of the fluid of control object, the magnitude | size of the space required along the direction of the fluid flow of a fluid passage does not change. Therefore, it is possible to install a flow rate control device that can control the flow rate of the fluid in various flow rate ranges in a predetermined space.

  The length of the third sensor channel may be longer or shorter than the length of the first sensor channel. The length of the flow path of the fourth sensor flow path may be longer or shorter than the length of the flow path of the second sensor flow path.

[Application Example 6]
A flow rate sensor unit for detecting a flow rate of a fluid flowing through a fluid passage,
The fluid passage is
A bypass flow path that constitutes the fluid passage in part along the direction of flow of the fluid;
A part of the fluid that flows through the fluid passage and before flowing through the bypass passage is branched, and then the part of the fluid joins the fluid that has passed through the bypass passage. 1 and a second sensor flow path, wherein the second sensor flow path is equal to the first sensor flow path and the flow path is longer than the first sensor flow path. A first sensor flow path and a second sensor flow path,
The flow sensor unit, for each sensor flow path,
An upstream resistor for heating a fluid flowing in the sensor flow path;
A downstream resistor that is provided downstream of the upstream resistor and whose temperature changes by a fluid flowing in the sensor flow path; and
An output unit that outputs a signal corresponding to a difference in resistance value between the upstream resistor and the downstream resistor;
The first and second sensor flow paths have the same distance along the flow direction of the fluid passage from the point where the part of the fluid is branched to the point where the part of the fluid is joined. A flow sensor unit configured as described above.

[Application Example 7]
A flow rate control device for controlling a flow rate of a fluid flowing in a fluid passage,
A fluid passage for flowing fluid;
A flow rate control valve unit for controlling the flow rate of the fluid flowing through the fluid passage;
A flow rate sensor unit for detecting a flow rate of the fluid flowing through the fluid passage;
A controller that controls the flow rate control valve unit based on the output of the flow rate sensor unit,
The fluid passage is
A part of the fluid passage is composed of a plurality of partial passages having the same passage cross section, and between the first portion of the fluid passage and the second portion downstream of the first portion. A bypass flow path comprising:
Each of the flow paths has the same cross section as the partial flow path, and a part of the fluid is branched from the fluid flowing through the fluid passage in the first part, and the part flows through the bypass flow path in the second part. A plurality of sensor flow paths for joining the part of the fluid to the fluid,
The flow sensor unit, for each sensor flow path,
An upstream resistor for heating a fluid flowing in the sensor flow path;
A downstream resistor that is provided downstream of the upstream resistor and whose temperature changes by a fluid flowing in the sensor flow path; and
An output unit that outputs a signal corresponding to a difference in resistance value between the upstream resistor and the downstream resistor;
The plurality of sensor flow paths include a first sensor flow path and a second sensor flow path that is longer than the first sensor flow path.
The flow rate sensor unit and the control unit include the signal based on the downstream resistor of the first sensor flow path and the second sensor flow path according to the size of the target flow rate of the fluid. A flow rate control device configured to control the flow rate control valve unit by properly using the signal based on the downstream resistor provided in the control unit.

The present invention can be realized in various modes as described below.
(1) A flow control device, a flow control system, and a flow control method.
(2) Flow rate sensor, flow rate detection method.

It is a block diagram of the flow control apparatus 100 of 1st Example. 2 is a schematic cross-sectional view showing a bypass flow path 16, a first sensor flow path 12, and a second sensor flow path 14 in the fluid passage 10. FIG. It is a figure which shows the circuit structure of the Wheatstone bridge 316 with which the flow sensor unit 30 is provided. It is a schematic sectional drawing which shows the structure of the 1st sensor flow path 12 and the 2nd sensor flow path 14 in the flow control apparatus of 2nd Example.

A. First embodiment:
FIG. 1 is a configuration diagram of a flow control device 100 according to the first embodiment. The gas source 200 supplies a gas Gs having a predetermined component to the semiconductor manufacturing apparatus 300. The flow control device 100 controls the flow rate of the gas Gs. The flow control device 100 includes a fluid passage 10 through which the gas Gs flows, a flow control valve unit 20, a flow sensor unit 30, and a control unit 40 that controls the flow control valve unit 20 based on the output of the flow sensor unit 30, Is provided. In FIG. 1, some configurations such as each configuration of the flow sensor unit 30 are shown at positions different from the actual arrangement in order to facilitate understanding of the technology. The actual position of the configuration shown in FIG. 1 without reflecting the actual position will be described later.

  The flow control valve unit 20 of the flow control device 100 controls the flow rate of the fluid flowing through the fluid passage 10. The flow control valve unit 20 includes a diaphragm 24 and an actuator 26. The diaphragm 24 constitutes a part of the outer wall of the fluid passage 10 and is provided so as to be deformable. The actuator 26 is composed of a laminated piezoelectric element, and presses the diaphragm 24 from the outside of the fluid passage 10 with a predetermined pushing amount in accordance with a signal from the control unit 40. The flow control valve unit 20 controls the fluid flow rate by adjusting the opening degree (valve opening degree) of the valve port 28 constituting a part of the fluid passage 10 by deforming the diaphragm 24.

  The fluid passage 10 includes a bypass passage 16, a first sensor passage 12, and a second sensor passage 14 on the upstream side of the flow control valve unit 20. The gas flowing downstream through the fluid passage 10 of the flow control device 100 flows through any of the bypass flow path 16, the first sensor flow path 12, and the second sensor flow path 14. That is, in the fluid passage 10, there is no gas flowing downstream without flowing through any of the bypass flow path 16, the first sensor flow path 12, and the second sensor flow path 14.

  FIG. 2 is a schematic cross-sectional view showing the bypass flow path 16, the first sensor flow path 12, and the second sensor flow path 14 in the fluid passage 10. In FIG. 2, the diagram on the right side is a cross-sectional view in a cross section along the gas flow direction Df. In FIG. 2, the diagram on the left side is a cross-sectional view in a cross section perpendicular to the gas flow direction Df. In order to facilitate understanding of the technology, in FIG. 2, the illustration of the configuration other than the bypass flow path 16, the first sensor flow path 12, and the second sensor flow path 14 is omitted. In FIG. 1, the first sensor flow path 12 and the second sensor flow path 14 are shown on the opposite sides of the bypass flow path 16 in order to facilitate understanding of the technology. However, in the actual configuration, the first sensor flow path 12 and the second sensor flow path 14 are provided on the same side (here, the upper side) with respect to the bypass flow path 16 as shown in FIG. It is done.

  The bypass passage 16 constitutes the fluid passage 10 in a partial range along the gas flow direction in the fluid passage 10. The bypass channel 16 includes a plurality of partial channels 162 having the same channel cross section and the same channel length. Note that “the cross sections of the flow paths are equal” means that the cross-sectional areas and shapes of the flow paths are equal. The inlets of the plurality of partial flow paths 162 are at the same position in the flow direction Df of the gas flowing through the fluid passage 10, and the outlets of the plurality of partial flow paths 162 are also at the same position in the flow direction Df of the gas flowing through the fluid passage 10. is there. That is, a bundle of a plurality of partial flow paths 162 constitutes the bypass flow path 16. The “flow direction Df of the gas flowing through the fluid passage 10” is the portion where the fluid flows separately into the bypass passage 16, the first sensor passage 12, and the second sensor passage 14. It means the direction of gas flow through the bypass channel 16.

  Each of the sensor flow paths 12 and 14 branches some of the gas flowing through the fluid passage 10 from the gas before flowing through the bypass flow path 16, and then branches to the gas flowing through the bypass flow path 16. The part of the gas that was done is merged. The first sensor flow path 12 is made of a stainless alloy. The second sensor flow path 14 is made of a nickel alloy having a higher thermal conductivity than the stainless alloy.

  As shown in FIGS. 1 and 2, the second sensor flow path 14 is longer than the first sensor flow path 12. However, when the member 12c constituting the first sensor flow path 12 and the member 14c constituting the second sensor flow path 14 are attached to the member 10c constituting the fluid passage 10, the flow of the fluid About the direction Df, it is provided with the magnitude | size and shape which become in the range W0. More specifically, when the member 12c constituting the first sensor flow path 12 and the member 14c constituting the second sensor flow path 14 are attached to the member 10c constituting the fluid passage 10, The fluid flow direction Df has the same width.

  The first sensor flow path 12 and the second sensor flow path 14 are used for measuring the flow rate of the gas flowing through the fluid passage 10 in different flow rate control modes. The lengths of the first sensor flow path 12 and the second sensor flow path 14 are set according to the size of the target flow rate in the flow rate control mode in which each is used.

  The point pd1 where the first sensor flow path 12 branches a part of gas and the point pd2 where the second sensor flow path 14 branches a part of gas are the direction of the gas flow in the fluid passage 10. Df is the same position. In addition, a location pc1 where the first sensor flow path 12 joins a part of the branched gas to the gas flowing through the bypass flow path 16, and the second sensor flow path 14 flows through the bypass flow path 16. The location pc2 where the part of the branched gas joins the gas is the same position in the gas flow direction Df of the fluid passage 10. When the position in the cross section perpendicular to the flow direction Df of the fluid passage 10 is not a problem and only the position along the flow direction Df of the fluid passage 10 is referred to, the positions of the branch points pd1 and pd2 are determined. Described as a branch point PD. Similarly, when the position in the cross section perpendicular to the flow direction Df of the fluid passage 10 does not matter and only the position along the flow direction Df of the fluid passage 10 is referred to, the positions of the confluence points pc1 and pc2 are described. Is expressed as a branch point PC.

  In the present embodiment, the distance L1 from the branch point pd1 of the first sensor flow path 12 to the confluence point pc1 is equal to the distance L2 from the branch point pd2 of the second sensor flow path 14 to the confluence point pc2. . By setting it as such an aspect, the length of the flow path of the 1st sensor flow path 12 and the 2nd sensor flow path 14 is set or changed according to the magnitude | size of the target flow volume of the gas to be controlled. Even so, the size of the space occupied by the first sensor flow path 12 and the second sensor flow path 14 in the flow direction Df does not change.

  In the present embodiment, the branch point pd1 of the first sensor flow path 12 and the branch point pd2 of the second sensor flow path 14 are at the same position PD in the flow direction Df, and the first sensor The junction pc1 of the flow path 12 and the junction pc2 of the second sensor flow path 14 are at the same position PC in the flow direction Df. For this reason, the branch point pd1 of the first sensor flow path 12 and the branch point pd2 of the second sensor flow path 14 are shifted in the direction Df, or the junction pc1 of the first sensor flow path 12 is obtained. Direction of the space occupied by the first sensor flow path 12 and the second sensor flow path 14 as compared with the aspect in which the confluence point pc2 of the second sensor flow path 14 is displaced in the direction Df. The size of Df can be reduced.

  The first sensor channel 12 and the second sensor channel 14 have a channel cross section equal to the channel cross section of the partial channel 162 of the bypass channel 16. Here, the partial channel 162 and the first and second sensor channels 14 are assumed to have circular channel cross sections having the same area.

  The flow rate of the gas flowing through the first sensor flow channel 12 with respect to the flow rate of the gas flowing through the bypass flow channel 16 by equalizing the flow channel cross sections of the first sensor flow channel 12 and the second sensor flow channel 14. And the ratio R2 of the flow rate of the gas flowing through the second sensor flow path 14 with respect to the flow rate of the gas flowing through the bypass flow path 16 are kept constant. And even if the gas pressure at the branch points pd1 and pd2 changes, the ratios R1 and R2 hardly change. That is, according to the present embodiment, the gas flowing through the fluid passage 10 as compared with the aspect in which the first sensor flow path 12, the second sensor flow path 14 and the partial flow path 162 have different flow path cross sections. The ratios R1 and R2 can be kept constant over a wider range of flow rates.

  As shown in FIG. 1, the flow sensor unit 30 includes upstream resistance wires 312 and 322 and downstream resistance wires 314 and 324 for the sensor flow paths 12 and 14. Hereinafter, the configuration of the flow sensor unit 30 will be described mainly using the configuration provided in the first sensor flow path 12.

  As shown in FIG. 1, an upstream resistance wire 312 and a downstream resistance wire 314 are wound around the surface of the pipe 12 c constituting the first sensor flow path 12. The downstream resistance wire 314 is wound around the surface of the pipe 12 c on the downstream side of the flow path with respect to the upstream resistance wire 312. The upstream resistance wire 312 and the downstream resistance wire 314 are made of a material whose resistance value changes according to the temperature. The upstream resistance wire 312 and the downstream resistance wire 314 have the same resistance value at the same temperature.

  FIG. 3 is a diagram illustrating a circuit configuration of the Wheatstone bridge 316 included in the flow sensor unit 30. A part of the Wheatstone bridge 316 includes an upstream resistance line 312 and a downstream resistance line 314 (see FIG. 1). In FIG. 1, the upstream resistance wire 312 and the downstream resistance wire 314 are illustrated separately from the Wheatstone bridge 316 in order to facilitate understanding of the technology.

  As shown in FIG. 3, the upstream resistance wire 312 and the downstream resistance wire 314 are connected in series. The Wheatstone bridge 316 includes a first comparison resistor 312c and a second comparison resistor 314c. The first comparison resistor 312c and the second comparison resistor 314c are directly connected. The first comparison resistor 312c and the second comparison resistor 314c, the upstream resistance wire 312 and the downstream resistance wire 314 are connected in parallel. A connection point p4 between the second comparison resistor 314c and the downstream resistance wire 314 is grounded. In FIG. 3, the current at the connection point p1 between the upstream resistance line 312 and the first comparison resistor 312c is indicated by an arrow I.

  The upstream resistance wire 312 and the downstream resistance wire 314 are energized to generate heat. In this state, when the gas flows through the first sensor flow path 12 (see FIG. 1), the gas takes heat from the upstream resistance wire 312 located on the upstream side of the first sensor flow path 12. , And flows to a position where the downstream resistance wire 314 is wound. Then, heat is passed to the downstream resistance wire 314 or heat is not taken away from the downstream resistance wire 314 as much as the upstream resistance wire 312. As a result, a temperature difference is generated between the upstream resistance wire 312 and the downstream resistance wire 314. Then, a difference is generated between the resistance values of the upstream resistance wire 312 and the downstream resistance wire 314.

  The difference in resistance value between the upstream resistance line 312 and the downstream resistance line 314 appears as a potential shift of the connection portion p2 between the upstream resistance line 312 and the downstream resistance line 314 in the Wheatstone bridge 316 (FIG. 3). reference). The shift in the potential of p2 can be measured by measuring the potential difference between the potential of the connection portion p3 between the first comparison resistor 312c and the second comparison resistor 314c and the potential of p2. The magnitude of the potential difference S11 is substantially proportional to the mass flow rate Q of the gas flowing through the first sensor flow path 12. The gain circuit 318 (see FIG. 1) included in the flow sensor unit 30 outputs a signal S12 that is proportional to the potential difference S11 between the potential of p3 and the potential of p2 in the Wheatstone bridge 316.

  On the other hand, as described above, the ratio R1 of the flow rate of the gas flowing through the first sensor flow channel 12 with respect to the flow rate of the gas flowing through the bypass flow channel 16 and the second sensor use with respect to the flow rate of the gas flowing through the bypass flow channel 16 The ratio R2 of the flow rate of the gas flowing through the flow path 14 is constant. For this reason, the sensor output signal S12 represents the mass flow rate of the gas flowing through the entire fluid passage 10 at that time.

  Similarly, the flow rate sensor unit 30 includes a Wheatstone bridge 326 and a gain circuit 328 for the second sensor flow path 14. The Wheatstone bridge 326 includes an upstream resistance line 322, a downstream resistance line 324, a first comparison resistance 322c, and a second comparison resistance 324c. The configuration and function of each part are the same as the configuration and function of the corresponding elements provided in the first sensor flow path 12. The gain circuit 328 outputs a signal S22 that is proportional to the potential difference S21 caused by the temperature difference between the upstream resistance line 322 and the downstream resistance line 324. For this reason, the sensor output signal S22 represents the mass flow rate of the gas flowing through the entire fluid passage 10 at that time.

  The control unit 40 (see FIG. 1) receives the signals S12 and S22 from the flow sensor unit 30. On the other hand, a command value signal St representing the target flow rate is separately received from the outside. In the first control mode in which the target flow rate of gas is small, the flow control valve unit 20 is controlled based on the command value signal St and the sensor signal S12. In the second control mode in which the target flow rate of gas is larger than that in the first control mode, the flow control valve unit 20 is controlled based on the command value signal St and the sensor signal S22. The user switches between the first control mode and the second control mode. The target flow rate range in the first control mode and the target flow rate range in the second control mode partially overlap.

  The point pd1 where the first sensor flow path 12 branches a part of gas and the point pd2 where the second sensor flow path 14 branches a part of gas are the direction of the gas flow in the fluid passage 10. About Df, it is the same position PD. For this reason, the flow rate and pressure of the gas in the fluid passage 10 at the branch points pd1 and pd2 are the same. On the other hand, the second sensor flow path 14 is longer than the first sensor flow path 12. For this reason, if the flow rate of the gas branched to each sensor flow path at the branch points pd1 and pd2 is the same, the flow rate of the gas flowing in the second sensor flow path 14 per unit time is the first flow rate. This is less than the flow rate of the gas flowing through the sensor flow path 12 per unit time. That is, the speed at which the heat deprived from the upstream resistance wire 322 in the second sensor flow path 14 moves in the second sensor flow path 14 is upstream in the first sensor flow path 12. The heat deprived from the side resistance wire 312 is smaller than the speed at which the heat moves in the first sensor flow path 12. Therefore, the temperature difference between the upstream resistance wire 322 and the downstream resistance wire 324 provided in the second sensor flow path 14 is equal to the upstream resistance wire 312 provided in the first sensor flow path 12 and the downstream side. Compared with the temperature difference of the resistance wire 314, even if the flow rate of the gas flowing through the entire fluid passage 10 is increased, the flow rate change is reflected better.

  As a result, when the target flow rate is in a small range, the flow rate control valve unit 20 is based on the output S12 based on the temperature difference between the upstream resistance wire 312 and the downstream resistance wire 314 provided in the first sensor flow path 12. When the target flow rate is in a large range, the flow rate is based on the output S22 based on the temperature difference between the upstream resistance wire 322 and the downstream resistance wire 324 provided in the second sensor flow path 14. The control valve unit 20 can be controlled with high accuracy. Then, by appropriately setting the length of the flow path of the second sensor flow path 14, the mass flow rate of the gas can be accurately detected even in a range where the target flow rate is high.

  In the present embodiment, the second sensor flow path 14 is made of a nickel alloy having a higher thermal conductivity than the stainless alloy. For this reason, even if the flow velocity of the gas flowing in the second sensor flow path 14 increases, the temperature difference between the upstream resistance wire 322 and the downstream resistance wire 324 provided in the second sensor flow path 14 is Easy to reflect the gas temperature. For this reason, even if the flow rate of the gas flowing through the entire fluid passage 10 increases, the flow rate sensor unit 30 can accurately detect and control the flow rate of the gas.

  In general, a material having high thermal conductivity such as a nickel alloy is expensive. However, in the present embodiment, the first sensor flow path 12 is made of a cheaper stainless alloy, not a nickel alloy. For this reason, according to the present embodiment, it is possible to reduce the cost of the entire flow rate sensor unit 30 and the flow rate control device 100 while securing the high accuracy flow rate measurement in the high flow rate range by the second sensor flow path 14. Can do. The upstream resistance line 312 and the downstream resistance line 314 provided in the first sensor flow path 12 are used when the target flow rate is in a small range. For this reason, even if the first sensor channel 12 is not made of a material having high thermal conductivity, the temperature difference between the upstream resistance wire 312 and the downstream resistance wire 314 and the resulting difference in potential difference are sufficiently large. The gas temperature can be reflected.

B. Second embodiment:
The flow rate control apparatus of the second embodiment is different from the first embodiment in the structure of the first sensor flow path 12 and the second sensor flow path 14. Other points of the flow control device of the second embodiment are the same as those of the flow control device 100 of the first embodiment.

  FIG. 4 is a schematic cross-sectional view showing the structures of the first sensor flow path 12 and the second sensor flow path 14 in the flow rate control apparatus of the second embodiment. In FIG. 4, the diagram on the right side of the middle stage is a cross-sectional view in a cross section along the gas flow direction Df. In FIG. 4, the diagram on the left side of the middle stage is a sectional view in a section perpendicular to the gas flow direction Df. In addition, in each figure, in order to make an understanding of a technique easy, there exists a part which is not shown with the cross section. In FIG. 4, the lower left diagram is a plan view of a portion related to the first sensor flow path 12 and the second sensor flow path 14 in the member 10 c constituting the fluid passage 10. In addition, in FIG. 4, illustration is abbreviate | omitted about structures other than the member which comprises each flow path and each flow path (for example, upstream resistance wire and downstream resistance wire).

  In the second embodiment, the first flow path member 12c constituting a part of the first sensor flow path 12 includes mounting portions 12dc and 12cc at positions on both ends of the flow path. The upstream attachment portion is referred to as a first upstream attachment portion 12dc. The downstream attachment portion is referred to as a first downstream attachment portion 12cc. Further, the second flow path member 14c constituting a part of the second sensor flow path 14 includes mounting portions 14dc and 14cc at positions on both ends of the flow path. The upstream attachment portion is referred to as a second upstream attachment portion 14dc. The downstream attachment portion is referred to as a second downstream attachment portion 14cc.

  On the other hand, the member 10c constituting the fluid passage 10 includes a first upstream flow path 17f1 (see the diagram on the left side of the middle stage in FIG. 4) that branches from the branch point pd1 and goes to the outside, and a first that goes from the outside to the junction point pc1. The downstream flow path 17e1 is provided. As shown in the lower part of FIG. 4, in the member 10c, a first upstream attachment portion 17d1 is provided in an opening portion of the first upstream flow path 17f1. A first downstream attachment portion 17c1 is provided in the opening portion of the first downstream flow path 17e1.

  Similarly, the member 10c constituting the fluid passage 10 includes a second upstream flow path 17f2 (see the diagram on the left side of the middle stage in FIG. 4) that branches from the branch point pd2 and goes to the outside, and a first that goes from the outside to the junction point pc2. Two downstream flow paths 17e2 are provided. As shown in the lower part of FIG. 4, in the member 10c, a second upstream attachment portion 17d2 is provided at the opening of the second upstream flow path 17f2. A second downstream attachment portion 17c2 is provided in the opening portion of the second downstream flow path 17e2.

  The first upstream attachment portion 12dc of the first flow path member 12c is connected to the first upstream attachment portion 17d1 of the member 10c that constitutes the fluid passage 10 (see the diagram on the left side of the middle stage in FIG. 4). . The first downstream mounting portion 17c1 is connected to the mounting portion 12cc of the first flow path member 12c (see the lower diagram in FIG. 4 and the upper right diagram). In other words, the first flow path member 12 c is attached to the member 10 c constituting the fluid passage 10. When the first flow path member 12c is attached to the member 10c, the flow path of the first upstream flow path 17f1, the first downstream flow path 17e1, and the first flow path member 12c is the first sensor flow path. 12 is configured.

  The first upstream attachment portion 17d1 of the member 10c and the first upstream attachment portion 12dc at the upstream end of the first flow path member 12c are detachably connected to each other. The first downstream attachment portion 17c1 of the member 10c and the attachment portion 12cc at the downstream end of the first flow path member 12c are also detachably connected to each other. FIG. 4 shows a state where the first flow path member 12c is removed from the member 10c constituting the fluid passage 10.

  Further, the second upstream attachment portion 14dc of the second flow path member 14c is connected to the second upstream attachment portion 17d2 of the member 10c constituting the fluid passage 10 (the diagram on the upper left side of FIG. 4). reference). The second downstream mounting portion 17c2 is connected to the mounting portion 14cc of the second flow path member 14c (see the lower diagram in FIG. 4 and the middle right diagram). That is, the second flow path member 14 c is attached to the member 10 c constituting the fluid passage 10. When the second flow path member 14c is attached to the member 10c, the flow path of the second upstream flow path 17f2, the second downstream flow path 17e2, and the second flow path member 14c is the second sensor flow path. 14 is configured.

  The second upstream attachment portion 17d2 of the member 10c and the second upstream attachment portion 14dc at the upstream end of the second flow path member 14c are detachably connected to each other. The second downstream attachment portion 17c2 of the member 10c and the attachment portion 14cc at the downstream end of the second flow path member 14c are also detachably connected to each other. FIG. 4 shows a state where the second flow path member 14 c is removed from the member 10 c constituting the fluid passage 10.

  A third flow path member 18c can be attached to the member 10c constituting the fluid passage 10 instead of the first flow path member 12c. As with the first flow path member 12c, the upstream resistance line and the downstream resistance line are wound around the third flow path member 18c. These resistance wires are connected to the Wheatstone bridge 316 (see FIG. 1) when the third flow path member 18c is attached to the member 10c constituting the fluid passage 10. As a result, the flow sensor unit 30 can generate the signal S12 based on the temperature difference between the upstream resistance wire and the downstream resistance wire wound around the third flow path member 18c.

  The third flow path member 18c includes an attachment portion 18dc at the upstream end of the flow path (see the left side of the middle stage in FIG. 4). The third flow path member 18c includes a mounting portion 18cc at the downstream end of the flow path. The attachment portion 18dc on the upstream end side is attached to the first upstream attachment portion 17d1 of the member 10c constituting the fluid passage 10 (see the left diagram in the middle of FIG. 4 and the lower diagram). The downstream end attachment portion 18cc is attached to the first downstream attachment portion 17c1 of the member 10c constituting the fluid passage 10.

When the third flow path member 18c is attached to the member 10c, the first upstream flow path 17f1, the first downstream flow path 17e1, and the flow path of the third flow path member 18c are for the third sensor. A flow path 18 is formed. The third sensor channel 18 has the same channel cross section as the first sensor channel 12 and is longer than the first sensor channel 12. However, the third sensor channel 18 is a channel having a shorter channel than the second sensor channel 14. When using a third sensor channel 18 the flow rate detection, a range larger maximum value of the flow rate than when the flow rate detected by the first sensor flow path 12, the second Thus, accurate flow rate detection can be performed in a range where the maximum flow rate is smaller than when the flow rate is detected using the sensor flow path 14 .

  The distance between the upstream end (attachment portion 18dc) of the flow path of the third flow path member 18c and the downstream end (attachment portion 18cc) of the flow path is the upstream end (attachment portion 12dc) of the flow path of the first flow path member 12c. ) And the downstream end of the flow path (attachment portion 12 cc).

  A fourth flow path member 19c can be attached to the member 10c constituting the fluid passage 10 instead of the second flow path member 14c. Similar to the second flow path member 14c, an upstream resistance line and a downstream resistance line are wound around the fourth flow path member 19c. These resistance wires are connected to the Wheatstone bridge 326 (see FIG. 1) when the fourth flow path member 19c is attached to the member 10c constituting the fluid passage 10. As a result, the flow sensor unit 30 can generate the signal S22 based on the temperature difference between the upstream resistance wire and the downstream resistance wire wound around the fourth flow path member 19c.

  The fourth flow path member 19c is provided with a mounting portion 19dc at the upstream end of the flow path (see the middle left diagram and the middle right diagram in FIG. 4). And the 4th flow path member 19c is equipped with the attaching part 19cc in the downstream end of a flow path (refer the figure of the middle stage right side of FIG. 4). The attachment portion 19dc on the upstream end side is attached to the second upstream attachment portion 17d2 of the member 10c that constitutes the fluid passage 10 (see the diagram on the right side of the middle stage in FIG. 4). The downstream end attachment portion 19cc is attached to the second downstream attachment portion 17c2 of the member 10c that constitutes the fluid passage 10 (see the right side of FIG. 4).

  When the fourth flow path member 19c is attached to the member 10c, the second upstream flow path 17f2, the second downstream flow path 17e2, and the flow path of the fourth flow path member 19c are for the fourth sensor. A flow path 19 is formed. The fourth sensor channel 19 has the same channel cross section as the second sensor channel 14 and is longer than the second sensor channel 14. Therefore, when the flow rate detection is performed using the fourth sensor flow path 19, the range where the maximum value of the flow rate is larger than when the flow rate detection is performed using the second sensor flow path 14 is more accurate. Accurate flow rate detection.

  The distance between the upstream end (attachment portion 19dc) of the flow path of the fourth flow path member 19c and the downstream end (attachment portion 19cc) of the flow path is the upstream end (attachment portion 14dc) of the flow path of the second flow path member 14c. ) And the downstream end of the flow path (attachment portion 14 cc). The first flow path member 12c, the third flow path member 18c, the second flow path member 14c, and the fourth flow path member 19c are all attached to the member 10c constituting the fluid passage 10. In this case, the fluid flow direction Df is provided in a size and a shape within the range W0.

  According to the second embodiment, by attaching the third flow path member 18c instead of the first flow path member 12c and attaching the fourth flow path member 19c instead of the second flow path member 14c, The first and second sensor flow paths can be replaced with the third and fourth sensor flow paths in accordance with the flow range of the gas to be controlled. In other words, various configurations can be adopted according to the flow range in which control is required, and a wide range of flow control can be handled.

  The flow control device of the second embodiment is required along the gas flow direction Df of the fluid passage 10 even if the members constituting the sensor flow path are replaced according to the flow range of the gas to be controlled. The size of the space is not changed. Therefore, it is possible to install a flow rate control device capable of controlling the gas flow rate in various flow ranges in a predetermined space.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.
C1. Modification 1:
In the above-described embodiment, the present invention has been described by taking as an example the flow rate control device that controls the flow rate of the gas supplied to the semiconductor manufacturing apparatus. However, the present invention is not limited to gas but can be applied to a flow rate control device that controls the flow rate of an arbitrary fluid such as a liquid.

C2. Modification 2:
In the above embodiment, the partial flow channel 162 and the first and second sensor flow channels 14 have circular flow channel cross sections having the same area. However, the partial flow path 162 and the first and second sensor flow paths 12 and 14 may have a cross-sectional shape other than circular. Moreover, the flow path cross section of the partial flow path 162 and the flow path cross sections of the first and second sensor flow paths 12 and 14 may have different cross sectional shapes and cross sectional areas.

C3. Modification 3:
In the above embodiment, the member 12c constituting the first sensor flow path 12 is made of a stainless alloy, and the member 14c constituting the second sensor flow path 14 is made of a nickel alloy. However, the member 12c constituting the first sensor flow path 12 and the member 14c constituting the second sensor flow path 14 can be made of other materials. However, the member 14 c constituting the second sensor flow path 14 is preferably made of a material having a higher thermal conductivity than the member 12 c constituting the first sensor flow path 12.

The materials that can constitute the member 12c of the first sensor flow path 12 and the member 14c of the second sensor flow path 14 and their thermal conductivity (unit: W / (m · K)) are shown below. Illustrate.
SUS316L: 16.3
Nickel-based alloy: 11-15
Titanium: 21.9
Zirconium: 22.7
Pure nickel: 90.5
Tantalum: 57.5
Platinum: 71.4
Gold: 315

  The member 12c constituting the first sensor flow path 12 and the member 14c constituting the second sensor flow path 14 may be, for example, any arbitrary materials whose thermal conductivity is separated from a predetermined value by a predetermined value or more. Two can be configured.

  Further, the member 12c constituting the first sensor flow path 12 and the member 14c constituting the second sensor flow path 14 do not need to be entirely composed of one kind of material. However, at least the member constituting the portion 14r around which the upstream resistance wire 322 and the downstream resistance wire 324 are wound in the second sensor flow path 14 is the upstream resistance wire in the first sensor flow path 12. 312 and the downstream resistance wire 314 are preferably made of a material having higher thermal conductivity than the member constituting the portion 12r around which the wire is wound.

C4. Modification 4:
In the above embodiment, the flow sensor unit 30 detects the flow rate upstream of the flow control valve unit 20. However, the flow sensor unit 30 may be configured to detect the flow rate on the downstream side of the flow control valve unit 20.

C5. Modification 5:
In the above embodiment, the target flow rate range in the first control mode and the target flow rate range in the second control mode partially overlap each other. However, for example, the target flow rate range in the first control mode may be a part of the target flow rate range in the second control mode.

C6. Modification 6:
In the above embodiment, the upstream resistance wire 312 and the downstream resistance wire 314 have the same resistance value at the same temperature. However, the upstream resistance wire 312 and the downstream resistance wire 314 may have different resistance values at the same temperature. However, at the same temperature, the relationship of [resistance value of upstream resistance wire 312] × [resistance value of second comparison resistor 314c] = [resistance value of downstream resistance wire 314] × [first comparison resistor 312c]. It is desirable that

  In the above-described embodiment, the temperature difference between the upstream resistance wires 312 and 322 and the downstream resistance wires 314 and 324 is detected by being converted into voltages S11 and S21 by the Wheatstone bridges 316 and 326. However, the temperature difference between the upstream resistance wires 312 and 322 and the downstream resistance wires 314 and 324 may be detected by other methods. For example, instead of the Wheatstone bridge, in the upstream resistance line and the downstream resistance line connected in series with each other, the other end of the downstream resistance line is grounded, and a current is applied by applying a constant potential to the other end of the upstream resistance line. It can also be set as the aspect provided with the structure which flows. In such an embodiment, a voltage reflecting the temperature difference between the upstream resistance wire and the downstream resistance wire can be obtained by measuring the potential of the connection portion between the upstream resistance wire and the downstream resistance wire. That is, the output unit that outputs a signal corresponding to the flow rate may be any unit that outputs at least a signal corresponding to the temperature of the downstream resistance wire as the downstream resistor. The upstream resistor is not limited to the resistance wire wound around the pipe constituting the flow path, but may be any one that can heat the fluid in the flow path, and the downstream resistor is a pipe constituting the flow path. Not only the resistance wire wound around the wire, but also any wire whose temperature changes depending on the fluid in the flow path.

C7. Modification 7:
In the first embodiment, the Wheatstone bridge 316 and the gain circuit 318 for the first sensor flow path 12 and the Wheatstone bridge 326 and the gain circuit 328 for the second sensor flow path 14 have different configurations. is there. However, each of these elements can also be configured in one place.

  Moreover, in the said Example, the control part 40 receives signal S12, S22 from the flow sensor unit 30 (refer FIG. 1). Then, the control mode based on each signal is switched according to the target flow rate of the gas. However, the flow sensor unit 30 may selectively output the signals S12 and S22 to the control unit 40 according to the setting. In such an aspect, for example, the user sets a signal to be output to the flow sensor unit 30. The control unit 40 controls the flow rate control valve unit based on the received signal.

C8. Modification 8:
In the above embodiment, each of the flow path members constituting the sensor flow path is within the range W0 with respect to the fluid flow direction Df when attached to the member 10c constituting the fluid passage 10. And is provided in shape. Here, as a more preferable aspect, there are the following aspects. That is, the outer dimension Wmax in the direction Df of the member constituting the longest flow path is preferably 1.3 times or less of the outer dimension Wmin in the direction Df of the member constituting the shortest flow path. More preferably, it is 2 times or less. The outer dimension Wmax is more preferably 1.1 times or less of the outer dimension Wmin. The “outside dimension” means a dimension between the most projecting portions of the member in the direction.

C9. Modification 9:
In the above-described embodiment, each sensor flow channel extends linearly when projected in a direction perpendicular to the direction Df, and has a shape that draws a rectangle when projected in a direction perpendicular to the direction Df. ing. However, each sensor flow path may have other shapes. For example, each sensor flow channel may have a shape having a curved portion that becomes Ω-shaped when projected in a direction perpendicular to the direction Df. In addition, the sensor channel having the longer channel is provided with a bending point that the sensor channel having the shorter channel does not have, thereby reducing the size of the space occupied by the sensor channel. It is preferable. For example, a sensor flow path having a longer flow path such as an “M” shape has two or more parts through which fluid flows in a direction away from the bypass flow path 16, and fluid flows in a direction approaching the bypass flow path 16. It can also be set as the aspect which has two or more site | parts which flow, and connects those site | parts at a bending point. If it is set as such an aspect, the magnitude | size of the space which the flow path for sensors occupies can be made small. Moreover, each sensor flow path can also be made into the shape which has a coil-shaped part.

DESCRIPTION OF SYMBOLS 10 ... Fluid path 10c ... Member which comprises fluid path 12 ... 1st flow path for sensors 12c ... 1st flow path member 12cc ... 1st downstream attachment part 12dc ... 1st upstream attachment part 12r ... 1st 1 sensor flow path where upstream resistance wire and downstream resistance wire are wound 14 second flow path 14 c second flow path member 14 cc second downstream mounting portion 14 dc 2nd upstream attachment part 14r ... part where upstream resistance wire and downstream resistance wire are wound in second sensor flow passage 16 ... bypass flow passage 17c1 ... first downstream attachment portion 17c2 ... second Downstream side mounting portion 17d1 ... first upstream side mounting portion 17d2 ... second upstream side mounting portion 17e1 ... first downstream channel 17e2 ... second downstream channel 17f1 ... first upstream channel 17f2 ... first 2 upstream flow path 18 ... 3rd Sensor flow path 18c ... Third flow path member 18cc ... Mounting portion 18dc ... Mounting portion 19 ... Fourth sensor flow path 19c ... Fourth flow path member 19cc ... Mounting portion 19dc ... Mounting portion 20 ... Flow control valve Unit 24 ... Diaphragm 26 ... Actuator 28 ... Valve port 30 ... Flow rate sensor unit 40 ... Control unit 100 ... Flow rate control device 162 ... Partial flow path 200 ... Gas source 300 ... Semiconductor manufacturing equipment 312, 322 ... Upstream resistance line 312c ... First 1 comparison resistance 314, 324 ... downstream resistance line 314c ... second comparison resistance 316, 326 ... Wheatstone bridge 318 ... gain circuit 328 ... gain circuit Df ... direction of gas flow through fluid passage 10 Gs ... gas I ... Arrow L1 indicating current L1 Distance from the branch point pd1 of the first sensor flow path 12 to the junction point pc1 L2. Distance from branch point pd2 of second sensor flow path 14 to junction point pc2 PC: position of junction point in the direction of gas flow PD ... position of branch point in the direction of gas flow S11: in Wheatstone bridge S12 ... sensor output signal S21 ... potential difference in the Wheatstone bridge S22 ... sensor output signal W0 ... range occupied by members constituting the sensor flow path in the direction Df pc1 ... confluence point of the first sensor flow path pc2 ... Confluence point of second sensor flow path pd1... Branch point of first sensor flow path pd2... Branch point of second sensor flow path

Claims (5)

A flow control device set,
(A) a flow rate control device for controlling the flow rate of the fluid flowing through the fluid passage,
A fluid passage for flowing fluid;
A flow rate control valve unit for controlling the flow rate of the fluid flowing through the fluid passage;
A flow rate sensor unit for detecting a flow rate of the fluid flowing through the fluid passage;
A controller that controls the flow rate control valve unit based on the output of the flow rate sensor unit,
The fluid passage is
A bypass flow path that constitutes the fluid passage in part along the direction of flow of the fluid;
A part of the fluid that flows through the fluid passage and before flowing through the bypass passage is branched, and then the part of the fluid joins the fluid that has passed through the bypass passage. 1 and a second sensor flow path, wherein the second sensor flow path is equal to the first sensor flow path and the flow path is longer than the first sensor flow path. A first sensor flow path and a second sensor flow path,
The flow sensor unit, for each sensor flow path,
An upstream resistor for heating a fluid flowing in the sensor flow path;
A downstream resistor that is provided downstream of the upstream resistor and whose temperature changes by a fluid flowing in the sensor flow path; and
An output unit that outputs a signal corresponding to a difference in resistance value between the upstream resistor and the downstream resistor;
The first and second sensor flow paths have the same distance along the flow direction of the fluid passage from the point where the part of the fluid is branched to the point where the part of the fluid is joined. Configured as
The flow rate sensor unit and the control unit include the signal based on the difference in the resistance value of the first sensor flow path and the second sensor flow path according to the size of the target flow rate of the fluid. The flow rate control valve unit can be controlled by properly using the signal based on the difference in resistance value.
The point at which the first sensor flow path branches the part of the fluid and the point at which the second sensor flow path branches the part of the fluid are in the flow direction of the fluid passage. In the same position,
The first sensor flow path joins the part of the fluid to the fluid flowing through the bypass flow path, and the second sensor flow path to the fluid that flows through the bypass flow path. And the point where the fluids of the fluid flow together are at the same position in the flow direction of the fluid passage,
The member constituting at least a part of the first sensor channel has a channel cross-section equal to the first sensor channel in the fluid passage, and the first and second sensor channels. The path is provided so as to be exchangeable with a member that can constitute at least a part of a third sensor flow path having a different flow path length.
The member constituting at least a part of the second sensor flow path has a flow path cross section equal to the second sensor flow path in the fluid passage, and the first to third sensor flow paths. A flow rate control device provided so as to be exchangeable with a member capable of constituting at least a part of a fourth sensor flow path having a different flow path length from the path ;
(B) the member capable of constituting at least a part of the third sensor flow path, replaceable with the member capable of constituting at least a part of the first sensor flow path;
(C) the member capable of constituting at least a part of the fourth sensor flow path and replaceable with the member capable of constituting at least a part of the second sensor flow path; A flow control device set. The flow control device set according to claim 1,
The bypass channel is a flow rate control device set including a plurality of partial channels each having a channel cross section equal to a channel cross section of the first and second sensor channels. The flow rate control device set according to claim 1 or 2,
The members constituting the range in which the upstream resistor and the downstream resistor are provided in the second sensor channel are the upstream resistor and the member in the first sensor channel. A flow control device set composed of a material having a higher thermal conductivity than members constituting the range in which the downstream resistor is provided. A flow sensor unit set,
(A) a flow rate sensor unit for detecting the flow rate of the fluid flowing through the fluid passage,
The fluid passage is
A bypass flow path that constitutes the fluid passage in part along the direction of flow of the fluid;
A part of the fluid that flows through the fluid passage and before flowing through the bypass passage is branched, and then the part of the fluid joins the fluid that has passed through the bypass passage. 1 and a second sensor flow path, wherein the second sensor flow path is equal to the first sensor flow path and the flow path is longer than the first sensor flow path. A first sensor flow path and a second sensor flow path,
The flow sensor unit, for each sensor flow path,
An upstream resistor for heating a fluid flowing in the sensor flow path;
A downstream resistor that is provided downstream of the upstream resistor and whose temperature changes by a fluid flowing in the sensor flow path; and
An output unit that outputs a signal corresponding to a difference in resistance value between the upstream resistor and the downstream resistor;
The first and second sensor flow paths have the same distance along the flow direction of the fluid passage from the point where the part of the fluid is branched to the point where the part of the fluid is joined. Configured as
The point at which the first sensor flow path branches the part of the fluid and the point at which the second sensor flow path branches the part of the fluid are in the flow direction of the fluid passage. In the same position,
The first sensor flow path joins the part of the fluid to the fluid flowing through the bypass flow path, and the second sensor flow path to the fluid that flows through the bypass flow path. And the point where the fluids of the fluid flow together are at the same position in the flow direction of the fluid passage,
The member constituting at least a part of the first sensor channel has a channel cross-section equal to the first sensor channel in the fluid passage, and the first and second sensor channels. The path is provided so as to be exchangeable with a member that can constitute at least a part of a third sensor flow path having a different flow path length.
The member constituting at least a part of the second sensor flow path has a flow path cross section equal to the second sensor flow path in the fluid passage, and the first to third sensor flow paths. A flow rate sensor unit provided to be exchangeable with a member capable of constituting at least a part of a fourth sensor flow path having a different flow path length from the path ;
(B) the member capable of constituting at least a part of the third sensor flow path, replaceable with the member capable of constituting at least a part of the first sensor flow path;
(C) the member capable of constituting at least a part of the fourth sensor flow path and replaceable with the member capable of constituting at least a part of the second sensor flow path; A flow sensor unit set comprising: A flow control device set,
(A) a flow rate control device for controlling the flow rate of the fluid flowing through the fluid passage,
A fluid passage for flowing fluid;
A flow rate control valve unit for controlling the flow rate of the fluid flowing through the fluid passage;
A flow rate sensor unit for detecting a flow rate of the fluid flowing through the fluid passage;
A controller that controls the flow rate control valve unit based on the output of the flow rate sensor unit,
The fluid passage is
A part of the fluid passage is composed of a plurality of partial passages having the same passage cross section, and between the first portion of the fluid passage and the second portion downstream of the first portion. A bypass flow path comprising:
Each of the flow paths has the same cross section as the partial flow path, and a part of the fluid is branched from the fluid flowing through the fluid passage in the first part, and the part flows through the bypass flow path in the second part. A plurality of sensor flow paths for joining the part of the fluid to the fluid,
The flow sensor unit, for each sensor flow path,
An upstream resistor for heating a fluid flowing in the sensor flow path;
A downstream resistor that is provided downstream of the upstream resistor and whose temperature changes by a fluid flowing in the sensor flow path; and
An output unit that outputs a signal corresponding to a difference in resistance value between the upstream resistor and the downstream resistor;
The plurality of sensor flow paths include a first sensor flow path and a second sensor flow path that is longer than the first sensor flow path.
The flow rate sensor unit and the control unit include the signal based on the difference in the resistance value of the first sensor flow path and the second sensor flow path according to the size of the target flow rate of the fluid. The signal based on the difference in the resistance value provided in is selectively used to control the flow control valve unit,
The point at which the first sensor flow path branches the part of the fluid and the point at which the second sensor flow path branches the part of the fluid are in the flow direction of the fluid passage. In the same position,
The first sensor flow path joins the part of the fluid to the fluid flowing through the bypass flow path, and the second sensor flow path to the fluid that flows through the bypass flow path. And the point where the fluids of the fluid flow together are at the same position in the flow direction of the fluid passage,
The member constituting at least a part of the first sensor channel has a channel cross-section equal to the first sensor channel in the fluid passage, and the first and second sensor channels. The path is provided so as to be exchangeable with a member that can constitute at least a part of a third sensor flow path having a different flow path length.
The member constituting at least a part of the second sensor flow path has a flow path cross section equal to the second sensor flow path in the fluid passage, and the first to third sensor flow paths. A flow rate control device provided so as to be exchangeable with a member capable of constituting at least a part of a fourth sensor flow path having a different flow path length from the path ;
(B) the member capable of constituting at least a part of the third sensor flow path, replaceable with the member capable of constituting at least a part of the first sensor flow path;
(C) the member capable of constituting at least a part of the fourth sensor flow path and replaceable with the member capable of constituting at least a part of the second sensor flow path; A flow control device set.

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