Fluid control valve and fluid control device

Abstract

The present invention can be used in a semiconductor manufacturing process and makes it possible to reduce dead volume while keeping a valve structure simple. The present invention comprises a flow path block 2 in which an internal flow path 2R is formed, a valve seat member 5 having a valve seat surface 5a, a valve body 6 that is provided with a permanent magnet 60 and has a seating surface 6a seated on the valve seat surface 5a, and an actuator part 7 that drives the valve body 6 by using the permanent magnet 60, the permanent magnet 60 being sealed by a corrosion-resistant alloy.

Description

Fluid control valve and fluid control device

[0001] The present invention relates to a fluid control valve and a fluid control device.

[0002] Conventionally, as shown in Patent Document 1, a so-called energized close type (normally open type) solenoid valve has been considered as a fluid control valve.

[0003] This solenoid valve comprises a valve body having a valve seat, a plunger arranged so as to be movable up and down on the valve body, an attractor arranged opposite the plunger, an electromagnetic coil for magnetizing the attractor, a valve element connected to the plunger and arranged so as to be movable up and down relative to the valve seat, and a biasing member for biasing the plunger in the valve-opening direction, and when current is applied to the electromagnetic coil, the plunger moves in the valve-closing direction against the biasing force of the biasing member. Specifically, the valve element is arranged so as to be movable up and down relative to the valve body arranged below the attractor so as to pass through the attractor, and is connected to the plunger arranged above the attractor, and is constantly biased upward (in the valve-opening direction) together with the plunger.

[0004] Japanese Patent Application Laid-Open No. 2020-148255

[0005] However, the above-mentioned solenoid valves have problems such as a complex structure and a large dead volume. In particular, when a solenoid valve is used in a process gas supply line in a semiconductor manufacturing device, it is desirable to reduce the area in contact with the process gas, but the above-mentioned solenoid valves have a large dead volume, making it difficult to reduce the area in contact with the gas.

[0006] Therefore, the present invention has been made to solve the above-mentioned problems, and its main object is to simplify the valve structure, reduce the dead volume, and enable use in semiconductor manufacturing processes.

[0007] That is, the fluid control valve according to the present invention comprises a flow path block in which an internal flow path is formed, a valve seat member having a valve seat surface, a valve body having a seat surface that seats on the valve seat surface and provided with a permanent magnet, and an actuator unit that acts on the permanent magnet to drive the valve body, and the permanent magnet is sealed with a corrosion-resistant alloy.

[0008] In this specification, the corrosion-resistant alloy is one that has corrosion resistance against gases used in, for example, semiconductor manufacturing processes, and specifically, fluorine (F ２ ), chlorine (Cl ２ ), bromine (Br ２ ), iodine (I ２ The corrosion-resistant alloy is a compound containing a halogen gas such as fluorine (F) or a halogen element, and has corrosion resistance against halogen-based gases such as HCl. The corrosion-resistant alloy is made of a material different from that of a permanent magnet and has higher corrosion resistance than a permanent magnet. More preferably, the corrosion-resistant alloy has higher corrosion resistance against gases used in semiconductor processes than a permanent magnet, and specifically, fluorine (F ２ ), chlorine (Cl ２ ), bromine (Br ２ ), iodine (I ２ The corrosion-resistant alloy is a halogen gas such as HCl or a compound containing a halogen element, and has corrosion resistance to the halogen-based gases such as HCl, more preferably to aqueous solutions and reaction products (mainly strong acids) generated when the halogen gas or halogen-based gas reacts with moisture.

[0009] According to this type of fluid control valve, a permanent magnet is provided on the valve element and acts on the permanent magnet to drive the valve element, thereby simplifying the valve structure and reducing the dead volume compared to conventional designs using a plunger. In particular, in the present invention, the permanent magnet is sealed with a corrosion-resistant alloy, preventing corrosion of the permanent magnet by the process gas even when used in a semiconductor manufacturing process. Therefore, the fluid control valve of the present invention can be suitably used in a process gas supply line in a semiconductor manufacturing device, reducing the area exposed to the process gas.

[0010] In a specific embodiment of the actuator unit, the actuator unit may include a core provided on the opposite side of the valve body from the seating surface, and a solenoid coil wound around the core. In this configuration, if the fluid control valve is a so-called energized-close type (normally open type), when the solenoid coil is not energized, the permanent magnet is attracted to the core, bringing the valve body into a fully open state, and when the solenoid coil is energized, the core and the permanent magnet repel each other, moving the valve body in the valve-closing direction.

[0011] As a specific embodiment for sealing the permanent magnet with a corrosion-resistant alloy, the valve body preferably includes a valve body main body made of a corrosion-resistant alloy, with a recess for accommodating the permanent magnet formed on the surface opposite the seating surface, and a sealing member made of a corrosion-resistant alloy that seals the opening of the recess with the permanent magnet accommodated in the recess. With this configuration, the permanent magnet can be sealed with the corrosion-resistant alloy simply by accommodating the permanent magnet in the recess of the valve body main body and sealing it with the sealing member, thereby simplifying the configuration of the valve body.

[0012] Specific examples of the corrosion-resistant alloy include stainless steel such as SUS316L.

[0013] The actuator core is provided facing the surface of the valve body opposite the seating surface, and the sealing member is preferably made of non-magnetic stainless steel so as not to impede the magnetic coupling between the core and the permanent magnet. Also, in order to make the valve body function as a yoke to further strengthen the magnetic coupling between the core and the permanent magnet, the valve body is preferably made of electromagnetic stainless steel.

[0014] Furthermore, it is desirable that the fluid control valve according to the present invention further include a distance adjustment mechanism for adjusting the distance between the core and the valve body. By adjusting the distance between the core and the valve body with this distance adjustment mechanism, it is possible to adjust (increase or decrease) the magnetic field (magnetic flux density) to an optimum value. For example, when it is desired to control a minute flow rate, increasing the distance between the core and the valve body weakens the magnetic coupling between the core and the valve body, making it possible to control the minute flow rate.

[0015] In a specific embodiment of the fluid control valve, the fluid control valve may further include a mounting block attached to the flow path block and housing the valve body, the actuator unit having a casing housing the core and the solenoid coil, and the core being fixed to the casing. With this configuration, the actuator unit can be removed together with the valve body by removing the mounting block from the flow path block, facilitating disassembly and maintenance. Furthermore, by attaching the casing to the mounting block, the core is provided facing the surface opposite the seating surface of the valve body. In this configuration, as a specific embodiment of the distance adjustment mechanism, it is desirable that the distance adjustment mechanism be formed by the casing and the mounting block.

[0016] A specific embodiment of the distance adjustment mechanism may include a male thread formed on one of the outer peripheral surface of the casing or the mounting block, and a female thread formed on the other of the outer peripheral surface of the casing or the mounting block, with which the male thread engages. With this configuration, the distance between the core and the valve body can be adjusted by the simple operation of rotating the casing relative to the mounting block.

[0017] It is desirable that the mounting block be provided with a fixing portion that is movable toward and away from the casing and that fixes the casing to the mounting block. With this configuration, the distance between the core and the valve body can be reliably maintained by fixing the casing with the fixing portion after adjusting the distance between the core and the valve body with the distance adjustment mechanism.

[0018] As a specific embodiment for fixing the casing with the fixing part, it is desirable that the casing has a cylindrical end portion at the tip portion on the flow path block side, the mounting block has a slit to accommodate the cylindrical end portion, the fixing part is provided on the side wall portion that forms the slit in the mounting block, and the cylindrical end portion is fixed to the side wall portion that forms the slit in the mounting block by the fixing part.

[0019] In order to facilitate disassembly and assembly of the fluid control valve and facilitate maintenance, it is desirable that the flow path block have an accommodating recess for accommodating the valve seat member.

[0020] In order to facilitate assembly of the fluid control valve, it is desirable that the mounting block be attached to the flow path block to fix the valve seat member accommodated in the accommodation recess.

[0021] In addition, the fluid control device according to the present invention is characterized by comprising the above-mentioned fluid control valve, a fluid sensor that measures the flow rate or pressure of the fluid, and a control unit that controls the opening degree of the fluid control valve based on the measurement value measured by the fluid sensor and a predetermined target value.

[0022] According to the present invention configured as described above, the valve structure can be simplified, the dead volume can be reduced, and the valve can be used in semiconductor manufacturing processes.

[0023] 1 is a schematic diagram showing a fluid control device according to one embodiment of the present invention; FIG. 1 is a cross-sectional view of a fluid control valve of the same embodiment; FIG. 2 is a perspective view and a cross-sectional view showing the configuration of a valve body of the same embodiment; FIG. 3 is a partially enlarged cross-sectional view of a fluid control valve (valve open state) of the same embodiment; FIG. 4 is a partially enlarged cross-sectional view of a fluid control valve (valve closed state) of the same embodiment; FIG. 5 is a partially enlarged cross-sectional view showing states before and after distance adjustment of the same embodiment; and FIG. 6 is a partially enlarged cross-sectional view of a fluid control valve (valve open state) of a modified embodiment.

[0024] An embodiment of a fluid control device using a fluid control valve according to the present invention will be described below with reference to the drawings. Note that, for ease of understanding, all of the drawings shown below are drawn in a schematic manner with appropriate omissions or exaggerations. Identical components are given the same reference numerals, and their descriptions will be omitted where appropriate.

[0025] <Device Configuration> The fluid control device 100 of this embodiment is used in a semiconductor manufacturing process by being incorporated into, for example, a semiconductor manufacturing device, and is provided, for example, on one or more gas supply lines connected to a semiconductor processing chamber to control the flow rate of process gas flowing through each gas supply line.

[0026] Specifically, the fluid control device 100 is a so-called differential pressure mass flow controller (differential pressure MFC), and as shown in FIG. 1, includes a flow path block 2 in which an internal flow path 2R is formed, and a fluid control device 3 including a flow sensor 31 and a fluid control valve 32 mounted on the flow path block 2.

[0027] The flow path block 2 is rectangular, and a flow rate sensor 31 and a fluid control valve 32 are provided on a predetermined surface of the flow path block 2. A concave accommodating recess 2M for attaching the fluid control valve 32 is also formed on a predetermined surface of the flow path block 2, and the accommodating recess 2M divides the internal flow path 2R into an upstream flow path 2R1 and a downstream flow path 2R2. One end of the upstream flow path 2R1 opens on, for example, the bottom surface of the accommodating recess 2M, and one end of the downstream flow path 2R2 opens on, for example, the bottom surface of the accommodating recess 2M.

[0028] The fluid control device 3 controls the fluid in the internal flow path 2R, and includes a flow rate sensor 31 that measures the flow rate of the fluid flowing through the internal flow path 2R, and a fluid control valve 32 that is provided upstream of the flow rate sensor 31. The valve opening of the fluid control valve 32 is feedback-controlled by the control unit 4, which will be described later.

[0029] The flow rate sensor 31 is a differential pressure type flow rate sensor, and has an upstream pressure sensor 31a provided upstream of a fluid resistance element 33, such as a restrictor or orifice, provided in the internal flow path 2R, and a downstream pressure sensor 31b provided downstream of the fluid resistance element 33. The upstream pressure sensor 31a and the downstream pressure sensor 31b are attached in a row together with the fluid control valve 32 on a predetermined surface of the flow path block 2. A flow rate calculation unit 4a of the control unit 4, which will be described later, calculates the flow rate Q flowing through the internal flow path 2R using the upstream pressure P1 of the fluid resistance element 33 detected by the upstream pressure sensor 31a and the downstream pressure P2 of the fluid resistance element 33 detected by the downstream pressure sensor 31b.

[0030] The fluid control valve 32 is provided upstream of the differential pressure flow sensor 31. Specifically, the fluid control valve 32 is a solenoid valve (electromagnetic valve) that controls the flow rate by moving a valve element toward and away from a valve seat using a solenoid. In this embodiment, it is a so-called normally open type that is fully open when the valve element is not driven. The fluid control valve 32 is controlled by a valve control section 4b of the control section 4. The detailed configuration of the fluid control valve 32 will be described later.

[0031] The control unit 4 has a flow rate calculation unit 4a that calculates the flow rate Q through the internal flow path 2R based on the upstream pressure P1 and the downstream pressure P2, and a valve control unit 4b that controls the fluid control valve 32 based on the flow rate Q calculated by the flow rate calculation unit 4a and a target flow rate (set value). The control unit 4 is a so-called computer that includes, for example, a CPU, memory, A / D and D / A converters, and input / output means, and performs the functions of the flow rate calculation unit 4a, the valve control unit 4b, etc. by executing a flow rate control program stored in the memory and causing various devices to work together.

[0032] <Detailed Configuration of Fluid Control Valve 32> As shown in FIGS. 2 to 5 , the fluid control valve 32 of this embodiment includes a valve seat member 5 having a planar valve seat surface 5 a, a valve element 6 having a planar seating surface 6 a that is in surface contact with the valve seat surface 5 a and is provided with a permanent magnet 60, and an actuator unit 7 that acts on the permanent magnet 60 to drive the valve element 6 by magnetic force.

[0033] 2 and 3, the valve seat member 5 is housed in the accommodation recess 2M of the flow path block 2. An annular valve seat surface 5a is formed on the upper surface of the valve seat member 5 facing the opening side of the accommodation recess 2M. The valve seat member 5 is made of a non-magnetic material, such as austenitic stainless steel (non-magnetic stainless steel) such as SUS316L.

[0034] Furthermore, a through-hole 51 is formed in the center of the inner side of the valve seat surface 5a of the valve seat member 5, penetrating from the valve seat surface 5a side to the opposite side of the valve seat surface 5a. This through-hole 51 communicates with the upstream flow path 2R1 that opens into the bottom surface of the accommodation recess 2M. A seal member S1 such as an O-ring is provided between the periphery of the through-hole 51 and the bottom surface of the accommodation recess 2M, providing a liquid-tight seal.

[0035] Furthermore, the valve seat member 5 is formed with a discharge passage 52 that allows the fluid that has flowed into the interior from the valve seat surface 5a to flow out to the downstream flow passage 2R2. In this embodiment, the discharge passage 52 is a through-hole that penetrates from the valve seat surface 5a side to the opposite side of the valve seat surface 5a on the outside of the valve seat surface 5a. This discharge passage 52 communicates with the upstream flow passage 2R1 that opens to the bottom surface of the installation recess 2M.

[0036] The valve element 6 has a generally rotary body shape and is disposed opposite the valve seat member 5 housed in the housing recess 2M, as shown in Figures 2 to 5. The permanent magnet 60 provided on the valve element 6 has a disk shape and is sealed with a corrosion-resistant alloy that is resistant to corrosion by gases used in semiconductor processes. Here, the permanent magnet 60 may be, for example, an alloy magnet such as an alnico magnet, a ferrite magnet, or a rare earth magnet such as a neodymium magnet.

[0037] Specifically, the valve body 6 has a valve body main body 61 having a recess 61M formed on the surface opposite to the seating surface 6a for accommodating the permanent magnet 60, and a sealing member 62 that seals the opening of the recess 61M when the permanent magnet 60 is accommodated in the recess 61M. The permanent magnet 60 in this embodiment is sealed by the valve body main body 61 and the sealing member 62.

[0038] The valve body 61 has a generally rotary body shape and includes a convex portion 611 with a flat seating surface 6a on its top surface. The valve body 61 of this embodiment has a circular seating surface 6a corresponding to the annular valve seating surface 5a. The recess 61M has a shape corresponding to the permanent magnet 60, and in this embodiment, is a generally circular recess in a plan view. The valve body 61 is formed from a corrosion-resistant alloy, such as stainless steel, that is corrosion-resistant to gases used in semiconductor processes. The valve body 61 of this embodiment is formed from a magnetic material, such as electromagnetic stainless steel, such as KM45, to function as a yoke.

[0039] The sealing member 62 has a generally circular disk shape corresponding to the opening shape of the recess 61M. This sealing member 62 seals the opening of the recess 61M to prevent corrosion of the permanent magnet 60 housed therein. The sealing member 62 is joined to the opening of the recess 61M by welding, such as laser welding. The sealing member 62 may also be joined to the opening of the recess 61M by mechanical or adhesive bonding. The sealing member 62 is formed from a corrosion-resistant alloy, such as stainless steel, that is corrosion-resistant to gases used in semiconductor processes. In this embodiment, the sealing member 62 is formed from a non-magnetic material, such as austenitic stainless steel (non-magnetic stainless steel) such as SUS316L, so as not to interfere with the magnetic coupling between the core 71 and the permanent magnet 60.

[0040] The valve element 6 is housed in a mounting block 8 that is attached to a predetermined surface (top surface) of the flow path block 2. The mounting block 8 is made of a non-magnetic material, such as austenitic stainless steel (non-magnetic stainless steel) such as SUS316L. The valve element 6 is supported on the mounting block 8 by a support member 9 made of an elastic material, such as a leaf spring. The support member 9 supports the valve element 6 with the seating surface 6a facing the valve seat surface 5a. Specifically, the support member 9 has an annular shape, and the protrusion 611 of the valve element 6 is inserted into a central opening 91 to support the valve element 6. The support member 9 and the valve element 6 may be integrally formed by welding, such as laser welding. The support member 9 and the valve element 6 may be integrally formed by mechanical or adhesive bonding. The support member 9 is made of a non-magnetic material, such as austenitic stainless steel such as SUS316L. Furthermore, the support member 9 has spring properties and is made of a corrosion-resistant material that is suitable for semiconductor gas contact parts, taking into consideration magnetic permeability.

[0041] The mounting block 8 is also attached to the flow path block 2 to fix the valve seat member 5 housed in the accommodation recess 2M. Specifically, the surface (lower surface) of the mounting block 8 facing the flow path block 2 comes into contact with the upper surface of the valve seat member 5, and the lower surface of the valve seat member 5 is pressed and fixed against the bottom surface of the accommodation recess 2M via a seal member S1. A seal member S2 such as a metal seal is provided between the mounting block 8 and the flow path block 2 to provide a liquid-tight seal.

[0042] As shown in Figures 2, 4, and 5, the actuator unit 7 has a core 71 provided opposite to the surface 6b of the valve body 6 opposite the seating surface 6a, a solenoid coil 72 wound around the core 71, and a casing 73 that houses the core 71 and the solenoid coil 72.

[0043] The core 71 has a generally cylindrical shape, one end (upper end in FIG. 2 ) of which is connected to the casing 73, and the other end (lower end in FIG. 2 ) of which faces a surface 6 b opposite the seating surface 6 a of the valve body 6. Specifically, the other end of the core 71 faces the opposite surface 6 b so as to be coaxial with the permanent magnet 60 provided on the valve body 6. The core 71 is formed from a magnetic material such as carbon steel for mechanical structures, for example, S45C.

[0044] The solenoid coil 72 is wound around the outer circumferential surface of the core 71, and more specifically, is wound around a bobbin 721 through which the core 71 is inserted. The bobbin 721 is provided so as to be slidable relative to the core 71. The bobbin 721 is made of a non-magnetic material, such as austenitic stainless steel, for example, SUS316L.

[0045] The casing 73 has a cylindrical shape, and its upper wall is connected to the upper end of the core 71. An elastic body 74 such as a wave spring is provided between the upper wall of the casing 73 and the solenoid coil 72 (specifically, the upper end of the bobbin 721) (see FIG. 2). The casing 73 is made of a magnetic material such as carbon steel for mechanical structures, e.g., S45C. The casing 73 and the core 71 may be integrally formed.

[0046] In addition, the casing 73 is attached to the mounting block 8, and by attaching the casing 73 to the mounting block 8, the core 71 connected to the casing 73 is arranged opposite the surface 6b opposite the seating surface 6a of the valve body 6.

[0047] The casing 73 extends to a position surrounding the valve disc 6, forming a magnetic path that guides the magnetic flux generated by the solenoid coil 72 to the periphery of the valve disc 6. The position surrounding the periphery of the valve disc 6 is a position facing the outer circumferential surface of the valve disc 6 in a direction perpendicular to the direction of advancement and retreat of the valve disc 6. With this configuration, the surface 6b (upper surface in FIGS. 2 and 3) of the valve disc 6 opposite the seating surface 6a is located closer to the core 71 (upper side) than the tip surface (lower surface in FIGS. 2 and 3) of the casing 73 that faces the flow path block 2. Specifically, the casing 73 extends to a position surrounding at least the upper half of the outer circumferential surface of the valve disc 6 when the valve disc 6 is in the valve closed state, for example.

[0048] 2, 4, and 5, the present embodiment is further provided with a distance adjustment mechanism 10 that adjusts the distance between the core 71 and the valve body 6. By adjusting the distance between the core 71 and the valve body 6 with the distance adjustment mechanism 10, the distance between the core 71 and the permanent magnet 60 is adjusted.

[0049] The distance adjustment mechanism 10 adjusts the distance between the opposing surfaces of the core 71 and the valve body 6, and is interposed between the casing 73 and the mounting block 8, and is formed by the casing 73 and the mounting block 8. Here, the opposing surfaces of the core 71 and the valve body 6 are the lower end surface 71a of the core 71 and the surface 6b of the valve body 6 opposite the seating surface 6a.

[0050] Specifically, the distance adjustment mechanism 10 has a male threaded portion 10a formed on the outer peripheral surface of the casing 73, and a female threaded portion 10b formed on the mounting block 8, into which the male threaded portion 10a screws. With this configuration, the casing 73 is attached to the mounting block 8 by screwing the male threaded portion 10a into the female threaded portion 10b. Furthermore, by rotating the casing 73 relative to the mounting block 8, as shown in FIG. 7 , the casing 73 advances and retreats in the axial direction relative to the mounting block 8, thereby adjusting the distance between the opposing surfaces of the core 71 and the valve body 6.

[0051] 2 and 4 to 6, the mounting block 8 is provided with a set screw 11, which is movable forward and backward relative to the casing 73, on the side wall 81 where the female thread portion 10b is formed, and which serves as a fixing portion for fixing the casing 73 to the mounting block 8. The set screw 11 is movable forward and backward in a direction perpendicular to the direction in which the casing 73 is moved by the distance adjustment mechanism 10.

[0052] 2 and 4 to 6, the casing 73 has a cylindrical end portion 73x at its tip, which is closer to the flow path block than the male thread portion 10a, and the set screw 11 presses against the cylindrical end portion 73x to fix the casing 73 to the mounting block 8. In this embodiment, the cylindrical end portion 73x has the same diameter as the housing main body portion 73y that houses the solenoid coil 72 in the casing 73. In other words, the casing 73 does not have a flange portion for mounting to the mounting block 8.

[0053] 4 and 5, the mounting block 8 has an annular slit 8S that accommodates the cylindrical end portion 73x, and a set screw 11 is provided in a radially outer side wall portion 811 that forms the slit 8S. A radially inner side wall portion 812 that forms the slit 8S is provided so as to surround the outer peripheral surface of the valve body 6. The cylindrical end portion 73x is pressed and fixed by the set screw 11 against the radially inner side wall portion 812 that forms the slit 8S.

[0054] In this embodiment, even if the casing 73 and core 71 move relative to the mounting block 8 due to the distance adjustment mechanism 10, the relative position of the solenoid coil 72 and the mounting block 8 (valve element 6) does not change (see FIG. 6 ). Specifically, the solenoid coil 72 is slidably mounted relative to the core 71 and casing 73. The solenoid coil 72 is also pressed toward the mounting block 8 by a wave spring 74 mounted between the upper wall of the casing 73 and the solenoid coil 72 (the upper end of the bobbin 721). The wave spring 74 fixes the solenoid coil 72 while accommodating dimensional tolerances. Note that the wave spring 74 may not be provided if the dimensional precision of each component is sufficient.

[0055] 4 and 5, a diaphragm seal 12 is provided between the lower end surface of the bobbin 721 and the upper end surface of the mounting block 8, providing a liquid-tight seal between the lower end surface of the bobbin 721 and the upper end surface of the mounting block 8. The diaphragm seal 12 is made of a non-magnetic material, such as austenitic stainless steel, for example, SUS316L.

[0056] Next, the operation of the fluid control valve 32 of this embodiment will be briefly described.

[0057] When no current flows through the solenoid coil 72 of the actuator unit 7 (when de-energized), the permanent magnet 60 provided on the valve element 6 is attracted to the core 71, and the valve element 6 is in a fully open state. In this embodiment, the core 71 and the permanent magnet 60 are attracted to each other via the sealing member 62 and the diaphragm seal 12.

[0058] When a current is passed through the solenoid coil 72, a magnetic flux is generated by the solenoid coil 72, magnetizing the core 71. Here, when the core side of the permanent magnet 60 is the north pole, the lower end of the core 71 is magnetized to the north pole, and when the core side of the permanent magnet 60 is the south pole, the lower end of the core 71 is magnetized to the south pole. As a result, the magnetized core 71 and the permanent magnet 60 repel each other, and the valve element 6 moves in the valve closing direction. The valve opening of the fluid control valve 32 is adjusted by controlling the current passed through the solenoid coil 72.

[0059] <Effects of the Present Embodiment> According to the fluid control device 100 of the present embodiment configured as described above, the valve element 6 is provided with a permanent magnet 60, and the valve element 6 is actuated by the permanent magnet 60. This simplifies the valve structure and reduces the dead volume compared to conventional configurations using a plunger. In particular, in the present embodiment, the permanent magnet 60 is sealed with a corrosion-resistant alloy, so that even when used in a semiconductor manufacturing process, the permanent magnet 60 can be prevented from corroding due to the process gas. Therefore, the fluid control valve 32 of the present embodiment can be suitably used in a process gas supply line in a semiconductor manufacturing device, and the area in contact with the process gas can be reduced.

[0060] In this embodiment, the sealing member 62 is made of non-magnetic stainless steel, which does not impede the magnetic coupling between the core 71 and the permanent magnet 60. Furthermore, the valve body 61 is made of electromagnetic stainless steel, which allows the valve body 61 to function as a yoke, thereby further strengthening the magnetic coupling between the core 71 and the permanent magnet 60.

[0061] Furthermore, in this embodiment, a distance adjustment mechanism 10 is provided for adjusting the distance between the core 71 and the valve element 6, and the magnetic field (magnetic flux density) can be adjusted (increased or decreased) to an optimum value by adjusting the distance between the core 71 and the valve element 6 with the distance adjustment mechanism 10. For example, when it is desired to control a minute flow rate, increasing the distance between the core 71 and the valve element 6 weakens the magnetic coupling between the core 71 and the valve element 6, making it possible to control the minute flow rate.

[0062] <Other Embodiments> For example, in addition to the configuration in which the permanent magnet 60 is sealed by the valve body main body 61 and the sealing member 62, the permanent magnet 60 may be configured such that its outer surface is covered with a coating member made of a corrosion-resistant alloy and fixed to the valve body 6. Corrosion of the permanent magnet can also be prevented by covering the permanent magnet 60 separately from the configuration of the valve body 6.

[0063] Furthermore, in addition to constructing the valve body 61 from magnetic stainless steel, the valve body 61 may be constructed in part or entirely from non-magnetic stainless steel. With this construction, the material cost of the valve body 6 can be reduced.

[0064] Although the distance adjustment mechanism 10 in the above embodiment is configured with a male thread portion 10a and a female thread portion 10b, it may also be configured with a set screw 11 as shown in Fig. 7. In this case, it is conceivable to form an annular slit 8S in the mounting block 8 to accommodate the cylindrical end portion 73x, and after adjusting the cylindrical end portion 73x in the up-down direction in the slit 8S, fix it with the set screw 11.

[0065] In addition, the male threaded portion 10a and female threaded portion 10b of the distance adjustment mechanism 10 in the above embodiment may be configured in reverse, i.e., the male threaded portion 10a may be formed on the mounting block 8 and the female threaded portion 10b may be formed on the inner peripheral surface of the casing 73.

[0066] Furthermore, the fluid control valve 32 of the above embodiment may be of a normally open type, or may be of a so-called normally closed type that is fully closed when the valve element 6 is not being driven. In a normally closed type configuration, when no current flows through the solenoid coil 72, the valve element 6 is urged against the valve seat member 5 by an elastic body such as the support member 9 to be fully closed. Then, when current flows through the solenoid coil 72, the core 71 and the permanent magnet 60 are attracted to each other, and the valve element 6 is moved in the valve opening direction.

[0067] In the above embodiment, the fluid control valve 32 is configured to be provided upstream of the flow rate sensor 31 , but it may also be configured to be provided downstream of the flow rate sensor 31 .

[0068] In the above embodiment, a pressure type flow sensor is used as the flow sensor 31 of the fluid control device 100, but a thermal type flow sensor may also be used. In this case, it is considered that the thermal type flow sensor is installed upstream of the fluid control valve 32. In addition to the flow sensor, a fluid sensor such as a pressure sensor may also be used.

[0069] Furthermore, the fluid control device 100 is not limited to the pressure type and the thermal type, but may be one in which a position sensor is provided in the fluid control valve 32 to measure the relative position between the valve seat surface 5 a and the seating surface 6 a, and the valve opening degree is feedback-controlled based on the measurement value of the position sensor. Furthermore, the fluid control device of the present invention is not limited to the flow rate control device of the above embodiment, but can also be applied to a pressure control device that controls the pressure of a fluid.

[0070] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention.

[0071] According to the present invention, the valve structure can be simplified, the dead volume can be reduced, and the valve can be used in semiconductor manufacturing processes.

[0072] DESCRIPTION OF SYMBOLS 100: Fluid control device 2: Flow path block 2R: Internal flow path 2M: Accommodating recess 32: Fluid control valve 31: Fluid sensor 4: Valve control section 5: Valve seat member 5a: Valve seat surface 6: Valve body 6a: Seating surface 60: Permanent magnet 61: Valve body main body 62: Sealing member 7: Actuator section 71: Core 72: Solenoid coil 73: Casing 73x: Cylinder end 8: Mounting block 8S: Annular slit 811: Radially outer side wall section 812: Radially inner side wall section 10: Distance adjustment mechanism 10a: Male thread section 10b: Female thread section 11: Set screw

Claims

1. A flow path block in which an internal flow path is formed, A valve seat member having a valve seat surface, A valve body having a seating surface that seats on the valve seat surface and provided with a permanent magnet, An actuator unit that acts on the permanent magnet to drive the valve body, and The permanent magnet is sealed with a corrosion-resistant alloy, a fluid control valve.

2. The actuator unit Has a core provided on the side opposite to the seating surface with respect to the valve body, And a solenoid coil wound around the core, When the solenoid coil is not energized, the permanent magnet is attracted to the core, and the valve body is in a fully open state, When the solenoid coil is energized, the core and the permanent magnet repel each other, and the valve body moves in the valve closing direction. The fluid control valve according to claim 1.

3. The valve body A valve body main body made of a corrosion-resistant alloy in which a recess for accommodating the permanent magnet is formed on the surface opposite to the seating surface, And a sealing member made of a corrosion-resistant alloy that seals the opening of the recess with the permanent magnet accommodated in the recess. The fluid control valve according to claim 1.

4. The corrosion-resistant alloy is stainless steel. The fluid control valve according to claim 1.

5. The valve body main body is formed of electromagnetic stainless steel, The sealing member is formed of non-magnetic stainless steel. The fluid control valve according to claim 3.

6. Further comprising a distance adjustment mechanism for adjusting the distance between the core and the valve body. The fluid control valve according to claim 2.

7. Further comprising a mounting block attached to the flow path block for accommodating the valve body, The actuator unit has a casing for accommodating the core and the solenoid coil, The core is fixed to the casing, The distance adjustment mechanism is constituted by the casing and the mounting block. The fluid control valve according to claim 6.

8. The distance adjustment mechanism Has a male screw portion formed on one of the outer peripheral surface of the casing or the mounting block, And a female screw portion formed on the other of the outer peripheral surface of the casing or the mounting block and screwed with the male screw portion. The fluid control valve according to claim 7.

9. The mounting block is provided with a fixing portion that is provided so as to be able to advance and retreat with respect to the casing and fixes the casing with respect to the mounting block. The fluid control valve according to claim 8.

10. The casing has a cylindrical end portion at the tip on the flow path block side, The mounting block has a slit for accommodating the cylindrical end portion, The fixing portion is provided on the side wall portion forming the slit in the mounting block, The flow control valve according to claim 9, wherein the cylindrical end portion is fixed to the side wall portion forming the slit in the mounting block by the fixing portion.

11. The flow control valve according to claim 7, wherein the flow path block has a housing recess for housing the valve seat member.

12. The flow control valve according to claim 11, wherein the mounting block is attached to the flow path block to fix the valve seat member housed in the housing recess.

13. A flow control valve according to any one of claims 1 to 12, A fluid sensor for measuring the flow rate or pressure of a fluid, A flow control device comprising: a control unit that controls the opening degree of the flow control valve based on a measurement value measured by the fluid sensor and a predetermined target value.