JPH11119835A - Mass flow controller and integrated flow rate controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller having a strong and safe structure that is never affected by a corrosive gas, etc., and also can resist a strong impact force, by using an anti-corrosion metal at a gas touching part of the controller. SOLUTION: A gas touching chip main body 13 has a 5-layer structure, for example, five sheets of anti-corrosion metal such as stainless steel plates, etc., of a proper thickness stacked on each other. Then, the main body 13 is bonded onto the upper surface of a silicone substrate 9 via a junction layer prepared between them or by means of an organic or inorganic adhesive. A gas flow path 14 includes a flow rate control part 15 and then a flow rate measurement part 16 from its upstream side. The part 15 adjusts an opening 20 which is formed to a flow rate control valve of an air pressure control system and located between a valve seat part 17 and a flow rate control part diaphragm 18. Thus, the part 15 can adjust the flow rate of gas flowing in the path 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a mass flow controller for controlling a gas flow rate and an integrated flow rate control device using the same.

[0002]

2. Description of the Related Art A mass flow controller is formed by forming a flow rate measuring section and a flow rate controlling section on a single substrate. It is used in a wide range of fields, from production equipment to R & D, such as remote control of gas and highly dangerous gases, as well as adjustment of mixed gas and mounting on test and research systems.

In recent years, there has been a demand for miniaturization of the above mass flow controllers, and a small mass flow controller as shown in FIG. 9 has been developed by micromachining technology utilizing photolithography and etching technology of semiconductor process technology. Has reached.

In FIG. 9, reference numeral 61 denotes a mass flow controller, which is provided on one surface (lower surface) of an integrated block 62. This mass flow controller 61 is configured as follows. That is, a substrate 63 made of ceramic is provided on one surface of the integrated block 62, and silicon layers 64 and 65 are stacked on the lower surface of the substrate 63. Then, a flow path 67 is formed in the substrate 63 so as to be continuous with the gas flow path 66 formed in the integrated block 62, and further, a concave portion 68 is formed in the silicon layer 64 so as to be continuous with the flow path 67. The concave portion 68 is connected to the integrated block 6 through another flow path 69 formed in the substrate 63.
2 is connected to another flow path 70 formed in the second flow path. In addition,
Reference numerals 71 and 72 denote sealing members interposed between the accumulation block 62 and the substrate 63.

[0005] Reference numeral 73 denotes a flow rate control unit formed between the flow path 67 and the flow path 69. This flow controller 73
Is configured as follows. That is, reference numeral 74 denotes a valve seat formed at the lower end of the flow passage 67, which is formed by etching simultaneously with the formation of the recess 68. The lower surface of the silicon layer 65 corresponding to the valve seat portion 74 is etched to form a diaphragm 75.
And a heat-resistant glass layer 76 provided so as to contact the lower surface of the silicon layer 65 with liquid. The opening (valve port) 78 between the valve seat portion 74 and the diaphragm 75 is moved by moving in the direction of the portion 74.
It is configured so that the degree of opening can be adjusted.

Reference numeral 79 denotes a flow rate measuring section formed between the flow path 69 and the flow path 70. This flow controller 79
A pressure sensor 81 provided on the lower surface of the substrate 63 so as to face a flow path 80 extending downward from a connection part of the flow paths 69 and 70.
And a sonic nozzle 82 provided in the flow path 70.
83 is silicon and 84 is a lid.

In FIG. 9, reference numeral 85 denotes a pressure regulator provided on the upper surface of the integrated block 62;
6 is a stop valve, 87 is a flow path provided in the accumulation block 62, and 88 to 90 are seal members.

In the mass flow controller 61 configured as described above, the gas indicated by arrow G
And then passes through a flow path 67 to reach a flow path 69 through an opening 78 determined by the position of the flow control unit 73 relative to the valve seat 74 of the diaphragm 75. Thereafter, the flow rate is measured by the flow rate measuring unit 79, and the measurement result is compared with a flow rate set value. Based on the measured flow rate, the opening degree of the opening 78 is adjusted, and the flow rate of the gas G is controlled so as to always be a predetermined flow rate. can do.

[0009]

However, in the above-mentioned conventional mass flow controller 61, the member in which the gas G flows is ceramics (substrate 63) or silicon (silicon layers 64 and 65).
There are the following problems. That is, since the ceramics are so-called porous, they easily absorb and desorb the gas G. Therefore, they are not suitable for high-purity gas and have a disadvantage that moisture is hardly released. Further, the heat-resistant glass (heat-resistant glass layer 76) has a disadvantage that it is strong against heat, but is susceptible to corrosive gas, and its bonding with silicon is vulnerable to strong impact force, so that it is not corroded. There is a danger of leaking toxic or toxic gases. In other words, the conventional mass flow controller is not suitable for adjusting a gas flow rate used for manufacturing a semiconductor or the like, and is not necessarily provided with mechanically sufficient strength.

The present invention has been made in consideration of the above-mentioned matters, and has an object to have a durable and safe structure which is not affected by a corrosive gas or the like and which can withstand a strong impact force. An object of the present invention is to provide a small and useful mass flow controller and an integrated flow control device using a plurality of the mass flow controllers.

[0011]

In order to achieve the above object, a mass flow controller according to the present invention comprises a silicon substrate portion, a gas contact chip portion joined to an upper surface thereof, and a gas container in an airtight container filled with an inert gas. Is formed in a multilayer structure in which a plurality of corrosion-resistant metal plates are laminated, a flow path is formed therein, and a flow rate measuring section and a flow rate control section are formed in the flow path. It is characterized by doing.

In the above mass flow controller,
Since the portion in contact with the gas (gas contact portion) is made of a corrosion-resistant metal, it is not affected by the corrosive gas and has sufficient mechanical strength. This mass flow controller can be miniaturized and mass-produced by applying a micromachining technology utilizing photolithography or etching technology of a semiconductor process technology.

The integrated flow control device of the present invention provides a plurality of mass flow controllers having the above-described excellent characteristics in parallel with each other, and each mass flow controller includes a pressure regulator, a pressure sensor, and a stop valve unit. It is characterized by being prepared.

[0014]

Embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment. In FIG. 1, reference numeral 1 denotes a mass flow controller, which is configured as follows. That is, 2 is a container body 3 made of an appropriate metal material, and a stem 4 made of an appropriate metal material for sealing an opening below the container body 3.
The sealed container 2 is filled with an inert gas such as nitrogen gas, and a mass flow controller body 5 is provided. The main body 5 of the mass flow controller includes a silicon substrate part 6, a gas contact chip part 7, and a joint block part 8. Less than,
The configuration of each of these units 6 to 8 will be described in detail.

First, the silicon substrate section 6 is configured as follows. 9 is an appropriate thickness (for example, 500 μm)
An IC circuit unit 10 as an arithmetic control unit is formed on a part of the upper surface of the silicon substrate 9. The IC circuit unit 10 has a function of measuring and controlling a flow rate and a function of transmitting and receiving signals to and from an external device. And 1
Reference numerals 1a and 12a denote a sensor main body of the pressure sensor 11 and a sensor main body of the temperature sensor 12 formed on the upper surface side of the silicon substrate 9, respectively, which are formed by appropriately etching the lower surface side of the silicon substrate 9. In addition, these sensor main bodies 11a,
Reference numeral 12a is a member that constitutes a flow rate measuring unit 16 described later.

Next, the structure of the gas contact tip portion 7 is shown in FIG.
This will be described with reference to FIG. Reference numeral 13 denotes a gas contact tip body, as shown in FIG. 2, having an appropriate thickness (for example, 100 to 50).
0 μm), and has a five-layer structure in which, for example, five stainless steel plates 13a to 13e are stacked, and has a size of, for example, about 1 to 2 mm square × 1 mm. The gas contact chip body 13 is provided on the upper surface of the silicon substrate 9 by providing a bonding layer therebetween, or by bonding with an organic or inorganic adhesive. Each part described below is formed on the gas contact tip body 13 by a technique such as etching.

Reference numeral 14 denotes a flow path through which the gas G to be controlled flows.
In the flow path 14, a flow control unit 15 and a flow measurement unit 16 are formed in this order from the upstream side.

First, the flow control unit 15 is configured as follows. Reference numeral 17 denotes a valve seat portion formed on the third layer 13c of the gas contact tip body 13;
3 is a flow rate control unit diaphragm formed on the second layer 13d. The flow control diaphragm 18 has a function as a valve body and a function as a partition. And 1
Reference numeral 9 denotes an air supply path for driving the flow control diaphragm 18. That is, the flow control unit 15 in the present embodiment is formed as a pneumatic control type flow control valve, and the valve seat 17 and the flow control unit diaphragm 1
The flow rate of the gas G flowing through the flow path 14 can be adjusted by adjusting the opening (valve port) 20 between the gas G and the flow path 8.

The flow rate measuring section 16 is configured as follows. Reference numerals 11b and 12b denote a pressure sensor diaphragm and a temperature sensor diaphragm formed on the fifth layer 13e of the gas contact chip body 13, respectively, and face the portions 21a and 21b communicating with the flow path 14 by half etching for improving sensitivity. It is provided in. 22
Is a sonic nozzle formed on the first layer 13 a of the gas contact tip body 13 and located downstream of the flow path 14. That is,
The flow measurement unit 16 in this embodiment includes a pressure sensor 11, a sonic nozzle 22, and a temperature sensor 12. The temperature sensor 12 measures the temperature for correcting that the flow rate in the flow rate measuring unit 16 depends on the temperature of the critical pressure.

The joint block 8 is provided with a joint for connection with an external gas, and is constructed as follows. Reference numeral 23 denotes a joint block body made of a corrosion-resistant metal such as stainless steel. The joint block 23 has joints 24 and 25 connected to the upstream side and the downstream side of the flow path 14, respectively, and a joint 26 connected to the air supply path 19.

In FIG. 1, reference numeral 27 denotes a pneumatic control valve for controlling the air pressure, which comprises, for example, an electromagnetic valve. By making the air pressure control valve 27 a normally open type (or a normally closed type), the mass flow controller 1 can be a normally closed type (or a normally open type). Reference numeral 28 denotes a lead pin extending below the stem 4, which is used to supply power for driving the IC circuit unit 10 and to exchange signals between the IC circuit unit 10 and an external device (not shown). Can be

In the mass flow controller 1 having the above configuration, the gas G is introduced into the mass flow controller 1 through the joint 24. In the mass flow controller 1, the pneumatic control valve 27 is controlled by a signal from the IC circuit unit 10.
Is opened, whereby the position of the flow control diaphragm 18 is controlled by the pressure of the introduced air, and the valve seat 1 is opened.
The degree of opening of the opening 20 between the flow path 7 and the flow control unit diaphragm 18 is adjusted, and the flow rate of the gas G flowing through the flow path 14 is controlled.

When the gas G passes through the pressure sensor 11 and the sonic nozzle 22, a signal is sent from each of them to the IC.
The flow rate measurement signal is obtained by being sent to the circuit section 10 and subjected to signal processing in the IC circuit section 10. This flow rate measurement signal is compared with a flow rate setting signal preset in the IC circuit section 10, and the result of the comparison is fed back to the pneumatic pressure control valve 27 to perform flow rate control. The gas G that has passed through the sonic nozzle 22 is led out of the mass flow controller 1 through the joint 25.

In the mass flow controller 1, since the gas contact tip 7 is made of a corrosion-resistant metal such as stainless steel, it is not affected by the corrosive gas. Further, the gas contact tip portion 7 has an extremely good bonding property with the silicon substrate 9 and has a robust structure, so that it is strong against an impact force.

In the mass flow controller 1, the mass flow controller main body 5 is housed in the closed container 1 filled with the inert gas and is isolated from the outside, so that it is chemically attacked or deteriorated. There is no such thing.

Further, the mass flow controller 1 includes:
By applying micromachining technology utilizing photolithography or etching technology of semiconductor process technology, miniaturization and mass production are possible.

In the mass flow controller 1 according to the first embodiment, the IC circuit section 10 may not be provided on the silicon substrate section 6 but may be provided on an external device (not shown). Further, the pneumatic control valve 27 may be provided in the silicon substrate 9.

FIGS. 3 to 5 show a second embodiment. The mass flow controller 1A according to the second embodiment is different from the mass flow controller 1 according to the first embodiment in the flow rate measuring section. However, the other configuration is exactly the same except for the difference. That is, the flow rate measuring section 29 of the mass flow controller 1A according to the second embodiment is configured as a thermal flow rate measuring section, and therefore, the flow path 14 is not provided with a sonic nozzle. Therefore, only different parts will be described.

That is, as shown in FIGS. 3 and 4,
Between the flow control unit 15 and the joint 25, the flow path 14
Is once branched into two flow paths 30 and 31 and then merged on the downstream side. Thin film flow sensors 32 and 33 such as heat-sensitive thin film heaters are provided in the flow path 30 near the silicon substrate section 6 and the other flow paths 31 are connected. It is a bypass channel.

FIG. 5 shows an example of the configuration of the thermal flow rate measuring section 29. In the sensor flow path 30 in which the thin film flow rate sensors 32 and 33 are provided, a plurality of parallel flow paths 30a are connected by half etching. Fourth layer 1 of gas chip body 13
It is formed on the lower surface side of 3d. The thin film flow sensors 32 and 33 are formed by providing a heat sensitive thin film heater on the lower surface side of the fifth layer 13e of the gas contact tip body 13 by half etching. Also, the sensor flow path 30
A plurality of parallel flow paths 31a are formed in the gas contact chip body 1 by half etching.
It is formed on the upper (or lower) side of the third second layer 13b. The number of the parallel flow paths 30a in the sensor flow path 30 is fixed, but the number of the parallel flow paths 31a in the bypass flow path 31 is appropriately determined according to the gas flow rate. The thin film flow sensors 32 and 33 are connected so as to form a bridge circuit with a resistor provided in the IC circuit unit 10.

The operation, operation and effect of the mass flow controller 1A according to this embodiment are the same as those of the mass flow controller 1 according to the above-described first embodiment, and therefore detailed description thereof will be omitted.

Next, FIG. 6 shows a third embodiment, in which the mass flow controller 1B according to the third embodiment is used.
Is the mass flow controller 1 according to the second embodiment.
A differs from A only in the flow control unit, and the other configurations are exactly the same. That is, the flow rate control unit 34 of the mass flow controller 1B according to the third embodiment is configured to drive the flow rate control unit diaphragm 18 as a valve body by the piezo actuator 35.
The air supply path 19 and the members related thereto are not provided.

That is, as shown in FIG. 6, the piezo actuator 35 is provided in a space portion (portion removed by etching) below the flow rate control diaphragm 18, and the voltage applied thereto is applied to the IC circuit portion 10.
It is configured to be adjusted by:

The operation and operation and effect of the mass flow controller 1B in this embodiment are the same as those of the mass flow controllers 1 and 1 in the first and second embodiments.
Since it is the same as A, its detailed description is omitted.

The mass flow controllers 1, 1A, 1B of the present invention are not limited to the above-described embodiment, but can be implemented in various modifications. For example, the number of layers of the corrosion-resistant metal in the gas contact tip portion 7 is arbitrary. Further, the flow control unit 15 (34) may be provided on the downstream side of the flow measurement unit 16 (29). Further, the flow rate control unit 34 and the flow rate measurement unit 16 may be combined. Further, the flow control unit diaphragm 18 in the flow control unit may be driven by a thermal method or a liquid.

In each of the above embodiments, the mass flow controller is a single unit. However, a plurality of mass flow controllers may be integrated to form an integrated flow control device. Hereinafter, this will be described as a fourth embodiment with reference to FIGS. 7 and 8. FIG. In these figures, the same components as those in FIGS. 1 to 6 indicate the same members.

In FIG. 7, reference numeral 40 denotes an integrated block made of a corrosion-resistant metal such as stainless steel. Inside the integrated block 40, a plurality of flow paths 41 are formed in parallel with each other. The plurality of flow paths 41 have independent gas introduction ports 42 on the upstream side, but the downstream side merges into one outside the integrated block 40 to form one gas outlet 43. Each flow path 41 has a mass flow controller 44 and a pressure regulator 45.
And a pressure sensor for checking that the pressure condition is in the sonic region by monitoring the pressure on the secondary side of the sonic nozzle, and the stop valve section 46 are provided in series with each other.

FIG. 8 shows that the integrated block 40 includes a mass flow controller 44, a pressure regulator 45,
FIG. 7 is a diagram showing a state where a pressure sensor and a stop valve section 46 are provided. As shown in this figure, a mass flow controller 44 is provided, for example, on the lower surface side of the integrated block 40, and is provided with a pressure regulator 45, a pressure sensor, and a stop valve unit provided on the upstream and downstream sides of the mass flow controller 44, respectively. 46 is provided on the upper surface side of the integrated block 40. In addition, 4
Reference numeral 1a denotes a flow path between the mass flow controller 44 and the pressure regulator 45, and reference numeral 41b denotes a flow path between the mass flow controller 44, the pressure sensor, and the stop valve section 46, all of which are formed in the integrated block 40. Reference numeral 47 denotes a seal member such as a metal O-ring.

Then, the mass flow controller 44
As the flow control unit 34 constituting the mass flow controller main body 5, a flow control unit whose diaphragm 18 is driven by a piezo actuator 35 is used.
The flow rate measuring unit 16 includes the pressure sensor 11 and the sonic nozzle 2
2 is used. The mass flow controller body 5 configured as described above includes a sealed container 48.
Housed within. The sealed container 48 is filled with an inert gas such as a nitrogen gas.

The pressure regulator 45 is obtained by removing the sonic nozzle 22 from the configuration of the mass flow controller 44. Reference numeral 49 denotes a pressure regulator body.

Further, the pressure sensor and the stop valve section 46 are obtained by removing the temperature sensor 12 from the configuration of the pressure regulator 45. Reference numeral 50 denotes a pressure sensor and a stop valve section main body.

According to the integrated flow rate control device configured as described above, the gas piping system is small and integrated, and is suitably used for automatic control and flow rate monitoring of gases used in semiconductor manufacturing and various industrial process gases. be able to.

The integrated flow control device of the present invention
The configuration of the flow control unit and the flow measurement unit is not limited to those exemplified in the above embodiment,
It goes without saying that those exemplified in the third embodiment may be appropriately combined.

[0044]

According to the mass flow controller of the present invention, since the portion in contact with the gas is made of a corrosion-resistant metal, it is not affected by the corrosive gas and has a sufficient mechanical strength. The mass flow controller can be miniaturized and mass-produced by applying a micromachining technology utilizing photolithography or etching technology of a semiconductor process technology.

In the integrated flow rate control device of the present invention, a plurality of mass flow controllers having the above-mentioned excellent features are used. It can be used in a wide range of fields such as automatic control and flow rate monitoring of various industrial process gases such as semiconductor manufacturing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a mass flow controller according to a first embodiment.

FIG. 2 is a longitudinal sectional view showing a gas contact tip portion used in the mass flow controller.

FIG. 3 is a longitudinal sectional view showing a mass flow controller according to a second embodiment.

FIG. 4 is a longitudinal sectional view showing a gas contact tip portion used in the mass flow controller.

FIG. 5 is an exploded perspective view of the gas contact tip portion.

FIG. 6 is a longitudinal sectional view showing a mass flow controller according to a third embodiment.

FIG. 7 is a diagram schematically showing a planar configuration of an integrated flow control device according to a fourth embodiment.

FIG. 8 is a longitudinal sectional view of the integrated flow control device.

FIG. 9 is a diagram for explaining a conventional mass flow controller.

[Explanation of symbols]

1, 1A, 1B, 44 ... mass flow controller, 2,
48 closed container, 6 silicon substrate part, 7 gas contact chip part, 10 arithmetic operation control part, 13a to 13e corrosion-resistant metal plate, 14 flow path, 15, 34 flow rate control part, 16, 2
9: flow rate measuring unit, 18: flow rate control unit diaphragm, 35
... Piezo actuator, 11 ... Pressure sensor, 22 ... Sonic nozzle, 32,33 ... Thin film flow sensor, 40 ... Integrated block, 45 ... Pressure regulator, 46 ... Pressure sensor and stop valve section.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Uesaka 11-5, Kamitobakotachimachi, Minami-ku, Kyoto, Kyoto Prefecture Inside ESTEC Co., Ltd. No. 11 in S-Tech Co., Ltd.

Claims (7)

[Claims] 1. A silicon substrate portion and a gas contact portion joined to an upper surface thereof are provided in a sealed container filled with an inert gas, and the gas contact portion is provided with a plurality of corrosion-resistant metal plates. A mass flow controller comprising a laminated multilayer structure, a flow passage formed therein, and a flow measurement unit and a flow control unit formed in the flow passage. 2. The mass flow controller according to claim 1, wherein an arithmetic control unit is formed on the silicon substrate. 3. The mass flow controller according to claim 1, wherein the diaphragm in the flow control unit is controlled by air pressure. 4. The mass flow controller according to claim 1, wherein the diaphragm in the flow control unit is controlled by a piezo actuator. 5. The mass flow controller according to claim 1, wherein the flow measuring unit comprises a pressure sensor and a sonic nozzle. 6. The mass flow controller according to claim 1, wherein the flow measuring unit comprises a thin film flow sensor. 7. An integrated block made of a corrosion-resistant metal, wherein a plurality of mass flow controllers according to claim 1 are provided in parallel with each other, and a pressure regulator, a pressure sensor, and a pressure sensor are provided in each mass flow controller. An integrated flow control device comprising a stop valve unit.