JP5269285B2 - Flow meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow measuring device and a flow measuring method capable of measuring properly the flow rate of fluid such as steam. <P>SOLUTION: This measuring device 32 for measuring the flow rate of fluid passing in a passage, equipped with a diaphragm 41 provided with an opening 40 has a constitution wherein the fluid passes the opening 40 from a passage 11a on the upstream side of the diaphragm 40 and then flows in a passage 31 on the downstream side of the diaphragm. The device 32 is also equipped with a strain gage 42 for detecting strain of the diaphragm 41, and an operation part 45 for detecting the flow rate based on an output from the strain gage 42. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

The present invention relates to a flow rate measuring device.

  For example, in the manufacturing process of semiconductor devices such as LSI, various processing such as cleaning processing and resist removal processing are performed by supplying processing fluid such as processing liquid and processing gas to a semiconductor wafer (hereinafter referred to as “wafer”). Processing is performed.

  In addition to a pump, a valve, and the like, a flow rate measuring device for measuring the flow rate in the piping is interposed in the piping that supplies the processing fluid (see, for example, Patent Document 1). As such a flow rate measuring device, a float type, a Karman vortex type, or the like is known.

JP 2002-151458 A

  However, for example, with respect to water vapor used as a processing fluid in wafer resist water-solubilization processing, there is a problem that it is difficult to select an appropriate flow rate measuring device. For example, when measuring with a flow meter using a mechanical method such as a float type, the float may stick to the taper tube due to the influence of condensation, etc. There was a risk of becoming unsafe. In addition, there was a risk that the flow meter would fail due to the heat of steam.

An object of the present invention is to provide a flow rate measuring device capable of suitably measuring the flow rate of a fluid such as water vapor.

In order to solve the above problems, according to the present invention, a measuring instrument for measuring the flow rate of a fluid passing through a flow path, comprising a diaphragm having an opening, wherein the fluid is a flow path upstream of the diaphragm. And through the opening to flow to the downstream flow path of the diaphragm, the upstream flow path of the diaphragm is connected substantially perpendicular to the flow direction of the downstream flow path of the diaphragm, The flow path on the downstream side of the diaphragm is a substantially semi-cylindrical internal space having a curved surface facing the diaphragm, a strain gauge for detecting strain of the diaphragm, and detection of the strain gauge A flow rate measuring device is provided, comprising: an arithmetic unit that detects the flow rate based on the value.

In this flow rate measuring device, a space having an inner diameter larger than the flow path upstream of the diaphragm is provided between the flow path upstream of the diaphragm and the diaphragm, and the outer diameter of the diaphragm is set to the space. It is good also as a structure matched with the internal diameter of. The flow path is provided with a flow rate adjusting valve for adjusting the flow rate of the fluid, and the flow rate of the fluid is controlled by adjusting the opening of the flow rate adjusting valve based on the flow rate detected by the calculation unit. A part may be provided. Further, the arithmetic unit, the strain differential pressure [Delta] P from the detection value of the gauge, the pressure P _o of the fluid on the downstream side of the pressure P of the fluid in the upstream side of the diaphragm the diaphragm (ΔP = P-P _o) You may ask for. Further, the calculation unit calculates the flow rate Q by the following formula: Q = CA (2ΔP / ρ) ^1/2 (C: constant, A: opening area of the opening, ΔP: pressure P of fluid upstream of the diaphragm) differential pressure between the pressure P _o of the fluid on the downstream side of the diaphragm, [rho: may be calculated based on the density of the fluid).

The fluid may be water vapor and ozone gas . The diaphragm may be formed by a resin mold, and the strain gauge may be sealed in the diaphragm by a resin .

  According to the present invention, it is possible to suitably measure the flow rate of the fluid by using the strain generated when the diaphragm is pushed by the fluid. Since the structure is simple, high cleanliness can be maintained and the possibility of failure is low. The flow channel of the flow channel measuring unit is relatively simple and the risk of condensation is low. Even if condensation occurs, the effect on measurement error is small.

  Hereinafter, in a preferred embodiment of the present invention, a flow rate provided in a supply path of a processing fluid in a substrate processing apparatus that performs a process of water-solubilizing a resist before removing the resist applied to the surface of a wafer as a substrate. This will be described based on the measuring device. As shown in FIG. 1, the substrate processing apparatus 1 includes a chamber 2 for storing a substantially disc-shaped wafer W.

  The chamber 2 includes a chamber body 2a whose upper surface is an opening, and a lid 2b that closes the upper surface opening of the chamber body 2a. The wafer W is placed in the chamber 2 substantially horizontally. The chamber 2 is connected to a main supply pipe 5 that supplies the processing fluid into the chamber 2 and a discharge pipe 6 that discharges the processing fluid from the chamber 2.

The main supply pipe 5 includes a steam supply pipe 11 for supplying pure water (DIW) water vapor (Vapor) as a processing fluid, an ozone gas supply pipe 12 for supplying ozone gas (O ₃ ) as a processing fluid, and nitrogen gas (N A nitrogen gas supply pipe 13 for supplying ₂ ) is connected via a junction 15.

  The steam supply pipe 11 is connected to a steam generator 21. The steam supply pipe 11 is provided with a flow rate adjusting valve 22 for opening and closing the flow path 11a in the pipe and adjusting the flow rate.

  The ozone gas supply pipe 12 is connected to an ozone gas generator 23. Further, the ozone gas supply pipe 12 includes a gas screen unit 24 that removes metal components from the ozone gas and cleans the ozone gas, and a flow rate adjustment valve 25 that opens and closes the flow path 12a in the tube and adjusts the flow rate. It is provided in this order from the 23rd side.

  The nitrogen gas supply pipe 13 is connected to a nitrogen gas supply source 26. The nitrogen gas supply pipe 13 is provided with a flow rate adjusting valve 27 for opening and closing the flow path 13a in the pipe and adjusting the flow rate.

  As shown in FIGS. 2 and 3, the merging portion 15 includes a main body 30, and an inner surface having an elongated rectangular tube shape extending in the lateral direction, that is, a substantially rectangular opening cross-sectional shape, is provided inside the main body 30. It has been. An internal space surrounded by the inner surface of the main body 30 is a flow path 31. The downstream end of the flow path 13 a in the nitrogen gas supply pipe 13 and the upstream end of the flow path 5 a in the main supply pipe 5 are connected to both ends of the flow path 31. The downstream end of the flow path 11a in the steam supply pipe 11 is connected to the flat surface portion 30a which is the upper surface of the inner surface of the main body 30, and further inside the ozone gas supply pipe 12 upstream from the flow path 11a. The downstream end of the flow path 12a is connected. The downstream end portions of the flow paths 11a and 12a are connected substantially perpendicularly to the flow direction of the flat portion 30a and the flow path 31, respectively.

  Note that in the vicinity of the junction 15, the steam supply pipe 11 and the ozone gas supply pipe 12 each have a substantially tubular shape. That is, the cross-sectional shape of the flow path 11a that is the internal space of the steam supply pipe 11 and the cross-sectional shape of the flow path 12a that is the internal space of the ozone gas supply pipe 12 are substantially circular. Further, the material of the steam supply pipe 11, the ozone gas supply pipe 12, the junction main body 30, and the main supply pipe 5, that is, the material of the inner wall surfaces of the flow paths 11a, 12a, 31, 5a, for example, fluorine resin, Resins with excellent chemical properties (ozone resistance) and heat resistance are used.

  Further, the confluence 15 is supplied from the flow path 11a to the flow path 31 and the vapor flow rate measuring device 32 according to the present embodiment for measuring the flow rate of the vapor supplied from the flow path 11a to the flow path 31. An ozone gas flow rate measuring device 33 according to the present embodiment for measuring the flow rate of ozone gas is provided.

  The steam flow rate measuring device 32 includes a diaphragm 41 having an opening (orifice) 40, a strain gauge 42 for detecting strain of the diaphragm 41, and a calculation unit 45 for detecting a flow rate based on the output of the strain gauge 42. Yes.

  As shown in FIGS. 3 and 4, the diaphragm 41 has a substantially circular flat plate shape, and is divided with respect to the flow direction of the flow path 11 a so as to partition the downstream end of the flow path 11 a and the upper part of the flow path 31. It is provided so as to cross at a substantially right angle. The outer peripheral edge of the diaphragm 41 is fixed with respect to the inner peripheral edge of the end of the flow path 11a. In the illustrated example, the diaphragm 41 is formed integrally with the main body 30, and is provided on the flat portion 30 a on the inner surface of the main body 30. The lower surface of the diaphragm 41 is a plane continuous with the planar portion 30a of the main body 30 in a planar shape. The upper surface of the diaphragm 41 is a substantially circular plane having the same outer diameter as the inner diameter of the flow path 11a.

The opening 40 is provided so as to penetrate from the upper surface side of the diaphragm 41 to the lower surface side in the central portion of the diaphragm 41, that is, the central portion in the radial direction of the flow channel 11a, and straight along the flow direction of the flow channel 11a. It has been. Sectional shape of the opening 40, substantially forms a circular with a smaller opening area _{A 1} than the flow path cross-sectional area of the channel ^{_{11a (A 1 = πd 1 2}} /4, d 1: the diameter of the opening 40).

  The diaphragm 41 is made of a flexible material such as resin, and is elastically deformed by receiving fluid pressure. Moreover, the diaphragm 41 may be formed of a fluororesin, or the surface of the diaphragm 41 may be coated with a fluororesin. By doing so, sufficient chemical resistance and heat resistance can be obtained. Further, the diaphragm 41 may be formed by resin molding. In this case, it is preferable to mold the strain gauge 42 so as to be sealed with resin. That is, a mold resin such as a fluororesin may be poured into a mold that forms the shape of the diaphragm 41, and the strain gauge 42 may be cured in the mold resin. Thereby, the diaphragm 41 incorporating the strain gauge 42 can be easily manufactured. In addition, the strain gauge 42 can be prevented from being damaged by covering the outer surface of the strain gauge 42 with resin.

  The strain gauge 42 is built in the inside of the diaphragm 41, and is connected to the arithmetic unit 45 via an electric circuit including a lead wire (not shown) and an amplifier provided as necessary. As the strain gauge 42, for example, a resistance wire strain gauge using a resistor made of metal is used. As the strain gauge 42, other structures such as a foil strain gauge and a semiconductor strain gauge may be used.

Calculating unit 45 is, for example, a microcomputer or the like, the detection value R ₁ which is the signal processing as required in the electric circuit a resistance value of the strain gauge 42 and received as an electric signal, based on the detected value R _1, the flow path The volume flow rate (measured value) Q ₁ [m ³ / s] of the steam supplied from 11a to the flow path 31 can be calculated.

Theory of the method of calculating the flow rate Q ₁ at the operating unit 45 is as follows. As is well known, the strain of the diaphragm 41 is the external force received by the diaphragm 41, that is, the differential pressure ΔP ₁ [Pa] between the pressure P ₁ of the fluid (steam) in the flow path 11a and the pressure P _o of the fluid in the flow path 31. It is correlated with (ΔP ₁ = P ₁ −P _o ). Therefore, the detected value R ₁ of the strain gauge 42 is correlated with the differential pressure ΔP ₁ . Further, the following equation (1) is known for the pipe orifice.
Q ₁ = C ₁ A ₁ (2ΔP ₁ / ρ ₁ ) ^1/2 (1)
Here, C ₁ is a constant (flow coefficient, about 0.6 to 0.8), A ₁ [m ² ] is the opening area of the opening 40, and ρ ₁ [kg / m ³ ] is the fluid (steam). Density. As apparent from the equation (1), the flow rate Q ₁ is proportional to the square root of the differential pressure ΔP ₁ . Therefore, the flow rate Q ₁ can be calculated from the detected value R ₁ correlated with the differential pressure ΔP ₁ .

Specifically, the detected value R ₁ ′ when a certain differential pressure ΔP ₁ ′ is given by an experiment is examined in advance, and the proportionality constant α ₁ may be obtained. Then, the differential pressure ΔP ₁ is uniquely determined from the detected value R ₁ (ΔP ₁ = α ₁ R ₁ ), and the flow rate Q ₁ can be calculated based on the equation (1).

  The ozone gas flow rate measuring device 33 has substantially the same functional configuration as the vapor flow rate measuring device 32 described above, that is, a diaphragm 41 and a strain gauge 42 provided between the end of the flow channel 12a and the upper portion of the flow channel 31. , An electric circuit (not shown) and a calculation unit 45 are provided. In the configuration of the ozone gas flow rate measuring device 33, the substantially same configuration as that of the vapor flow rate measuring device 32 is denoted by the same reference numeral in the present specification and the drawings, and detailed description thereof is omitted. Of course, for example, the size of the diaphragm 41 and the opening 40 of the ozone gas flow rate measuring device 33 may be different from that provided in the steam flow rate measuring device 32.

Computing section 45 of the ozone gas flow meter 33 receives the detection value R ₂ which is the signal processing as required resistance value of the strain gauge 42 of the ozone gas flow meter 33 as an electric signal, based on the detected value R _2, A flow rate (measurement value) Q ₂ [m ³ / s] of ozone gas supplied from the flow channel 12 a to the flow channel 31 is calculated. Theoretical calculation method of the flow rate Q ₂ is the same as the case of the flow rate Q ₁ described above. That is, from the detected value R ₂ correlated with the differential pressure ΔP ₂ [Pa] (ΔP ₂ = P ₂ −P _o , P ₂ : pressure of the fluid (ozone gas) in the flow path 12a), the following equation (2) is obtained. Can be calculated based on this.
Q ₂ = C ₂ A ₂ (2ΔP ₂ / ρ ₂ ) ^1/2 (2)
Here, _{C 2} is a constant (flow coefficient, about ^{_{0.6~0.8), A 2 [m 2}} ] is the opening area of the opening 40 in the ozone gas flow meter ^{_{33 (A 2 = πd 2 2}} /4, d ₂ : The diameter of the opening 40 in the ozone gas flow rate measuring device 33), ρ ₂ [kg / m ³ ] is the density of the fluid (ozone gas). More specifically, the detected value R ₂ ′ when a certain differential pressure ΔP ₂ ′ is given by experiment is examined in advance, and its proportionality constant α ₂ is obtained (ΔP ₂ = α ₂ R ₂ ). it is sufficient to calculate the flow rate Q ₂ based on).

  As shown in FIG. 1, the flow rate adjusting valves 22, 25, 27, the calculation unit 45 of the steam flow rate measuring device 32, and the calculation unit 45 of the ozone gas flow rate measuring device 33 control the functional elements of the substrate processing apparatus 1. The control unit 50 is connected to each other via a signal line (not shown).

Control unit 50 monitors the measured values to Q ₁ flow rate by the steam flow meter 32, with the measured value Q ₁ is such that the target value, a function of adjusting the opening degree of the flow rate adjusting valve 22. That is, the flow rate of the steam is controlled by the feedback control system including the flow rate adjusting valve 22, the steam flow rate measuring device 32, and the control unit 50.

The control unit 50 monitors the measured value Q ₂ of the flow rate by the ozone gas flow meter 33, so that the measured value Q ₂ becomes the target value, a function of adjusting the opening of flow control valve 25. That is, the flow rate of ozone gas is controlled by the feedback control system including the flow rate adjustment valve 25, the ozone gas flow rate measuring device 33, and the control unit 50.

  As shown in FIG. 5, the gas clean unit 24 includes a bubbler tank 61 for bubbling ozone gas into the stored pure water, a pipe 62 for feeding a mixed fluid of steam and ozone gas derived from the bubbler tank 61 while cooling, water cooling A Peltier cooler 63, a filter 64, and a condensation separation tank 65 of the type are provided.

  At the bottom of the bubbler tank 61, an end portion of a supply pipe 12b, which is a part of the ozone gas supply pipe 12 and forms a portion between the ozone gas generator 23 and the gas screen unit 24, is disposed. Further, a pure water supply passage 71 for supplying pure water into the bubbler tank 61 and a heater 72 for heating and keeping the inside of the bubbler tank 61 are provided. The pipe 62 is connected to the ceiling portion of the bubbler tank 61. In the bubbler tank 61, pure water supplied from the pure water supply path 71 is stored.

  The pure water supply path 71 is connected to the bottom of the bubbler tank 61. The pure water supply path 71 is provided with a flow rate adjusting valve 73 for opening and closing the pure water supply path 71 and adjusting the flow rate, and a drain path 74 for draining the bubbler tank 61. An open / close valve 75 is interposed in the drainage path 74. Pure water in the bubbler tank 61 is drained out of the gas screen unit 24 via a pure water supply path 71 and a drainage path 74.

  On the side wall of the bubbler tank 61, liquid level sensors 76a, 76b and 76c for detecting the liquid level are provided in this order from the bottom. The detection signals of the liquid level sensors 76a to 76c are transmitted to the controller 77 that controls the opening degree of the flow rate adjusting valve 73. The controller 77 monitors the position of the liquid level in the bubbler tank 61 based on the detection signals of the liquid level sensors 76a, 76b and 76c, and gives a command to open the flow rate adjusting valve 73 when the liquid level falls from a predetermined height. Then, the bubbler tank 61 is appropriately replenished with pure water. That is, control is performed so that the liquid level is maintained at a desired height.

  The supply pipe 12b is provided with a purge gas supply path 78 for supplying, for example, air (Air) as a purge gas. Note that nitrogen or the like may be used as the purge gas. When purging the inside of the bubbler tank 61, the purge gas is supplied into the bubbler tank 61 via the purge gas supply path 78 and the supply pipe 12b, thereby pushing out the ozone gas in the bubbler tank 61 to the pipe 62 and exhausting it. It is supposed to let you. Further, by supplying purge gas from the bubbler tank 61 to the pipe 62, filter 64, and condensation separation tank 65, the ozone gas in the pipe 62, filter 64, and condensation separation tank 65 is pushed out to a supply pipe 12c described later and exhausted. , The pipe 62, the filter 64, the condensation separation tank 65, and the supply pipe 12c can be purged. By purging the bubbler tank 61, the pipe 62, the filter 64, the condensation separation tank 65, etc., ozone gas harmful to the human body can be prevented from leaking during maintenance work of the gas screen unit 24, for example. Etc. can be performed safely.

  A serpentine tube portion 62 a is formed in the middle of the pipe 62. The serpentine tube portion 62a has, for example, a shape that is meandered so as to bend a plurality of times alternately in the opposite direction.

  The Peltier cooler 63 is provided on the downstream side of the serpentine tube portion 62a. The Peltier cooler 63 includes a Peltier element (not shown) and a cooling water supply passage 81 that cools the heat radiation side of the Peltier element, and is arranged so that the heat absorption surface of the Peltier element is close to the outer surface of the pipe 62. Has been. Then, by circulating the cooling water through the cooling water supply path 81, heat is transferred from the heat radiation side of the Peltier element, and the heat radiation side is forcibly cooled.

  The filter 64 has a structure in which a cylindrical filter body 64b is provided in a box-shaped housing 64a. The filter main body 64b is provided with the length direction directed in the vertical direction. The downstream end of the pipe 62 is connected to the side wall of the housing 64a and opens outside the filter body 64b. On the other hand, a pipe 83 for leading fluid from the inside of the filter main body 64b is connected to the ceiling portion of the housing 64a. In addition, a drainage path 84 for discharging liquid, impurities, and the like accumulated outside the filter body 64b is connected to the bottom of the housing 64a. An open / close valve 85 is interposed in the drainage path 84. The downstream end of the drainage channel 84 is connected to the bottom of the condensation separation tank 65.

  A liquid level sensor 86 for detecting the liquid level is provided on the side wall of the housing 64a. The detection signal of the liquid level sensor 86 is transmitted to the controller 87 that controls the opening / closing of the opening / closing valve 85. Although the on-off valve 85 is closed in a normal state, when the liquid level is detected by the liquid level sensor 86, a command is given from the controller 87 to open. That is, when the liquid has accumulated up to a predetermined height in the housing 64 a, the on-off valve 85 is opened and drained into the condensation separation tank 65 through the drainage path 84.

  The pipe 83 is connected to the upper part of the condensation separation tank 65. A supply pipe 12 c that is a part of the ozone gas supply pipe 12 and that forms a portion between the gas screen unit 24 and the flow rate adjustment valve 25 is connected to the ceiling portion of the condensation separation tank 65. Further, a drainage path 91 for draining the liquid in the condensation separation tank 65 to the outside of the gas screen unit 24 is connected to the bottom of the condensation separation tank 65. An open / close valve 92 is interposed in the drainage passage 91.

  On the side wall of the condensation separation tank 65, liquid level sensors 93a, 93b, 93c for detecting the liquid level are provided in this order from the bottom. The detection signals of the liquid level sensors 93a to 93c are transmitted to the controller 94 that controls the opening / closing of the on-off valve 92. The on-off valve 92 is closed in a normal state. However, for example, when the liquid level is detected by the liquid level sensor 93b, a command is given from the controller 94 to open. That is, when the liquid accumulates to a predetermined height in the condensation separation tank 65, the on-off valve 92 is opened and drained by the drainage passage 91. Further, after the opening / closing valve 92 is opened, for example, when the liquid level is detected by the liquid level sensor 93a, a command is given from the controller 94, and the opening / closing valve 92 is closed again. That is, when the liquid level in the condensation separation tank 65 falls to a predetermined appropriate height, the drainage by the drainage passage 91 is stopped.

  In such a configuration, the high-temperature ozone gas supplied from the ozone gas generator 23 is ejected from the end of the supply pipe 12b immersed in the heated pure water in the bubbler tank 61, and floats in the pure water. It is led out from the bubbler tank 61 by a pipe 62 in a state of being mixed with water vapor. The pure water in the bubbler tank 61 at this time is preferably heated to about 50 ° C. to 80 ° C. by the heater 72, for example. The mixed fluid of ozone gas and steam immediately after being led out from the bubbler tank 61 to the pipe 62 is in a high temperature state, but the heat of the fluid passes through the meandering flow path in the serpentine pipe part 62a. Heat is released to the atmosphere through 62a. As a result, the mixed fluid is cooled by air. After the air cooling, the fluid in the pipe 62 is further efficiently cooled by the Peltier cooler 63 and is brought to room temperature or lower. By cooling in this way, the vapor mixed with the ozone gas is condensed into water droplets. At this time, the metal component contained in the ozone gas is taken into the water droplets and separated from the ozone gas. Thereafter, when ozone gas and water droplets in the pipe 62 flow into the filter 64, water drops and foreign matter are collected outside the filter body 64 b, and ozone gas flows into the filter body 64 b and passes through the pipe 83 to form the condensation separation tank 65. Introduced in. In the condensation separation tank 65, while the ozone gas is retained, the fine mist contained in the ozone gas falls to the lower part of the condensation separation tank 65 and is separated from the ozone gas. After the moisture is thus separated, ozone gas is led out from the dew condensation tank 65 by the supply pipe 12c.

  In this way, after the vapor is mixed with the ozone gas, the vapor is condensed so that the metal component mixed in the ozone gas when the ozone gas is generated in the ozone gas generator 23 is taken into the water droplet and removed together with the water droplet from the ozone gas. be able to. That is, since clean ozone gas with reduced metal components can be supplied to the wafer W in the chamber 2, it is possible to prevent the wafer W from being adversely affected by the metal components.

  Note that, as described above, before cooling by the Peltier cooler 63, the cost required for cooling the fluid can be reduced by naturally cooling in the serpentine tube portion 62a. In addition, the effect of collecting the metal component can be enhanced by cooling the fluid at the relatively slow cooling rate in the serpentine tube portion 62a.

  As shown in FIG. 1, the discharge pipe 6 is provided with a flow rate adjusting valve 95 for opening and closing the flow path 6 a in the discharge pipe 6 and adjusting the flow rate. The pressure in the chamber 2 can be adjusted to a predetermined value by adjusting the opening degree of the flow rate adjusting valve 95 and the opening degree of the flow rate adjusting valves 22 and 25 described above.

  Next, processing of the wafer W in the substrate processing apparatus 1 configured as described above will be described. First, the lid 2b is removed from the chamber body 2a, the wafer W is stored in the chamber body 2a, and the upper surface opening of the chamber body 2a is closed by the lid 2b. A sealed processing space is formed in the chamber 2. Then, the wafer W in the chamber 2 is heated by a heater (not shown).

  After the temperature of the wafer W is raised, the flow rate adjusting valves 25 and 95 are opened, and ozone gas having a predetermined concentration is supplied from the ozone gas generator 23 into the chamber 2 through the ozone gas supply pipe 12, the junction 15 and the main supply pipe 5. Supplied. The ozone gas supplied from the ozone gas generator 23 is purified by the gas clean unit 24 and then supplied into the chamber 2 while being controlled to a predetermined flow rate by adjusting the flow rate adjusting valve 25 by the control unit 50. The atmosphere in the chamber 2 is pushed out to the discharge pipe 6 by the supplied ozone gas and exhausted. Thus, the chamber 2 is filled with the ozone gas atmosphere.

  After the inside of the chamber 2 is filled with ozone gas, the flow rate adjusting valve 22 is opened, and ozone gas and vapor are simultaneously supplied into the chamber 2. The resist applied to the surface of the wafer W is water-soluble (oxidized) by the mixed fluid of ozone gas and vapor. The steam supplied from the steam generator 21 and the ozone gas supplied from the ozone gas generator 23 pass through the flow path 11a in the steam supply pipe 11 and the flow path 12a in the ozone gas supply pipe 12 respectively, and enter the junction 15. After being introduced and joined together at the junction 15, it flows into the flow path 5 a in the main supply pipe 5 and is introduced into the chamber 2.

When the steam flows into the junction 15, the flow rate of the steam is measured by the steam flow rate measuring device 32. In the steam flow measuring device 32 shown in FIG. 2, the steam flows from the flow path 11 a upstream of the diaphragm 41 through the opening 40 and flows into the flow path 31 downstream of the diaphragm 41. It flows in a direction substantially perpendicular to the flow path 11a and flows out from the flow path 31 to the flow path 5a. The diaphragm 41, by the differential pressure [Delta] P ₁ of the pressure _{P o} of the fluid at a pressure _{P 1} and the flow passage 31 of the steam in the channel 11a, is pushed toward the flow path 11a side in the flow path 31 side, the flow path 31 side Deforms so that it protrudes convexly. Thus, the strain in the diaphragm 41 occurs, the detection value _{R 1} of the strain gauge 42 is changed. Then, the flow rate measurement value Q ₁ is obtained from the detection value R ₁ in the calculation unit 45 of the steam flow rate measuring device 32, and the measurement value Q ₁ is transmitted to the control unit 50 and monitored by the control unit 50.

Further, when the ozone gas flows into the junction 15, the flow rate of the ozone gas is measured by the ozone gas flow rate measuring device 33. In the ozone gas flow rate measuring device 33, ozone gas passes from the flow path 12 a upstream of the diaphragm 41 through the opening 40 and flows into the flow path 31 downstream of the diaphragm 41, and enters the flow path 12 a in the flow path 31. On the other hand, it flows in a substantially right angle direction and flows out from the flow path 31 to the flow path 5a. The diaphragm 41, by the differential pressure [Delta] P ₂ of the pressure _{P o} of the fluid at a pressure _{P 2} and the flow path 31 of the ozone gas in the channel 12a, is pushed toward the passage 12 side to the flow path 31 side, the flow path 31 side Deforms so that it protrudes convexly. Thus, the strain in the diaphragm 41 occurs, the detection value _{R 2} of the strain gauge 42 is changed. Then, in the calculation unit 45 of the ozone gas flow rate measuring device 33, the measurement value Q _{2 of the} flow rate is obtained from the detection value R ₂ , and the measurement value Q ₂ is transmitted to the control unit 50 and monitored by the control unit 50.

As described above, the flow rates of the steam and the ozone gas introduced into the merging portion 15 are measured by the steam flow rate measuring device 32 and the ozone gas flow rate measuring device 33, respectively, and these measured values Q ₁ and Q ₂ are respectively predetermined values. Thus, the values are respectively adjusted to predetermined values under the control of the control unit 50. For example, the measured values Q ₁ and Q ₂ are controlled to be about 3 [liter / min] (5 × 10 ⁻⁵ [m ³ / s]). The pressure in the chamber 2 is adjusted to about 75 [kPa], for example.

  When the resist water-solubilization process using the mixed fluid is completed, the flow rate adjusting valves 22 and 25 are closed, and the supply of ozone gas and vapor is stopped. Then, the flow rate adjusting valve 27 is opened, and nitrogen gas is supplied from the nitrogen gas supply source 26 into the chamber 2 through the nitrogen gas supply pipe 13, the junction 15, and the main supply pipe 5. As a result, the ozone gas and vapor in the chamber 2 are pushed out by the nitrogen gas and exhausted by the exhaust pipe 6.

  Thus, after the inside of the chamber 2 is purged with nitrogen gas, the lid 2b is removed from the chamber body 2a, and the wafer W is unloaded from the chamber 2. As described above, a series of processing steps in the substrate processing apparatus 1 is completed.

  According to the vapor flow rate measuring device 32 and the ozone gas flow rate measuring device 33 of the substrate processing apparatus 1, the flow rate of the fluid can be suitably measured by using the strain generated when the diaphragm 41 is pushed by the fluid. Since it has a relatively simple structure in which an opening 40 is provided between the flow path 11a (12a) and the flow path 31, there is little possibility of impurities or the like adhering to or staying in the vicinity of the diaphragm 41, and high cleanliness. Can keep the degree. Also, the possibility of failure is low. In particular, in the conventional flow type flow rate measuring device, the shape of the flow path is complicated, so there is a concern that condensation may occur when measuring the flow rate of the steam, making measurement impossible. Since the flow path is simple, the risk of condensation is low. Even if condensation occurs, the structure is simple, so there is little effect on measurement errors and it is possible to perform highly accurate measurements.

  Further, according to the steam flow rate measuring device 32 and the ozone gas flow rate measuring device 33, the flow rates of the steam and the ozone gas can be accurately and reliably measured. Therefore, the control of the flow rate in the control unit 50 based on these measured values is also accurately performed. Is called. Accordingly, steam and ozone gas are supplied into the chamber 2 at appropriate flow rates, and the pressure in the chamber 2 is also adjusted appropriately. Thereby, highly reliable substrate processing can be performed.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various changes and modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  In the present embodiment, the channel cross-sectional shapes of the channels 11a and 12a are substantially circular, and the shapes of the diaphragm 41 and the opening 40 are also substantially circular. However, these shapes are not limited to a circular shape. It may be.

  In the present embodiment, the flow path 31 on the downstream side of the diaphragm 41 has a substantially rectangular tube shape and is oriented substantially perpendicular to the flow path 11a (12a) on the upstream side of the diaphragm 41. The shape of the flow path on the downstream side may be a substantially semi-cylindrical shape, for example, a flow path 31 ′ shown in FIG. In FIG. 6, an inner surface of the main body 30 ′ is provided with an elongated substantially semi-cylindrical shape extending in the lateral direction (the direction from the front to the rear in FIG. 6), that is, the opening cross-sectional shape is a substantially semicircular shape. The internal space surrounded by the inner surface is a flow path 31 ′. The inner surface of the main body 30 ′ has a flat surface portion 30 a ′ on which the diaphragm 41 is provided, and a curved surface portion 30 b ′ that is a substantially semi-cylindrical curved surface. That is, the surface (the bottom surface in FIG. 6) facing the diaphragm 41 is formed as a curved surface. Further, the flat surface portion 30a 'is an upper surface, and the curved surface portion 30b' is provided in a concave shape downward. The downstream end of the channel 11a (12a) is connected to the plane part 30a ′ from above the channel 31 ′, and is substantially perpendicular to the flow direction of the plane part 30a ′ and the channel 31 ′. Is provided. The diaphragm 41 is provided so as to partition the downstream end of the flow channel 11a (12a) and the upper portion of the flow channel 31 ', as in the above embodiment. The lower surface of the diaphragm 41 is a flat surface continuous with the flat surface portion 30a 'and faces the curved surface portion 30b'. According to such a configuration, the volume of the flow path 31 ′ can be made smaller than when the flow path 31 ′ has a substantially rectangular cross section (the chain line in FIG. 6), and the main body 30 ′ can be downsized. Can do. In addition, by providing a smooth curved surface portion 30b ′ on the inner surface of the main body 30 ′ and reducing the corners of the inner surface, resistance to the flow of fluid in the flow path 31 ′ is suppressed, and the fluid can be sent efficiently. it can.

  For example, as shown in FIG. 7, a space (undercut portion) 100 having an inner diameter larger than that of the flow path 11a (12a) is provided between the flow path 11a (12a) and the diaphragm 41, and the outer diameter of the diaphragm 41 is provided. May be made larger than the inner diameter of the flow path 11a (12a) in accordance with the inner diameter of the space 100. In this case, for example, even when the inner diameter of the flow path 11a (12a) is relatively small, the outer diameter of the diaphragm 41 can be increased and a structure in which the distortion is generated sufficiently can be achieved. Therefore, the flow rate can be measured with high accuracy.

  In the present embodiment, the diaphragm 41 is provided between the flow path 11a (12a) and the flow path 31 to measure the flow rate flowing into the flow path 31 from the flow path 11a (12a). As shown in FIG. 8, a diaphragm 41 may be provided in the middle of the flow path 11a (12a), and the flow rate in the middle of flowing in the flow path 11a (12a) may be measured.

  In the present embodiment, the vapor flow rate measuring device 32 and the ozone gas flow measuring device 33 provided in the substrate processing apparatus 1 that performs the resist water-solubilization treatment on the wafer W have been described. The present invention is not limited to the one provided in the device 1, and can be applied to flow measurement in piping of various devices and systems. Of course, the fluid to be measured is not limited to vapor, ozone gas, or the like, and may be other gas or liquid. In the present embodiment, a substrate to be processed to which a processing fluid such as vapor or ozone gas is supplied is not limited to a wafer, and may be a glass substrate for LCD, a photomask substrate, a CD substrate, or the like. good.

  The present invention can be applied to a flow rate measuring device.

It is explanatory drawing explaining the structure of a substrate processing apparatus. It is a longitudinal cross-sectional view of the confluence | merging part provided with the steam flow rate measuring device and the ozone gas flow rate measuring device. It is a longitudinal cross-sectional view by the II line in FIG. It is a longitudinal cross-sectional view by the II-II line in FIG. It is explanatory drawing explaining the structure of a gas screen unit. It is a longitudinal cross-sectional view of the junction part concerning another embodiment. It is a longitudinal cross-sectional view of the steam flow rate measuring device or ozone gas flow rate measuring device concerning other embodiment. It is a longitudinal cross-sectional view concerning embodiment provided with the steam flow rate measuring device or the ozone gas flow rate measuring device in the middle of the steam supply tube or the ozone gas supply tube.

Explanation of symbols

W wafer 1 substrate processing apparatus 2 chamber 11 vapor supply pipe 11a flow path 12 ozone gas supply pipe 12a flow path 15 merging section 22 flow rate adjustment valve 25 flow rate adjustment valve 31 flow path 32 vapor flow rate measurement device 33 ozone gas flow rate measurement device 40 opening 41 diaphragm 42 Strain gauge 45 Calculation unit 50 Control unit

Claims (7)

A measuring instrument for measuring the flow rate of a fluid passing through a flow path,
It has a diaphragm with an opening,
The fluid is configured to flow from a flow path on the upstream side of the diaphragm to the flow path on the downstream side of the diaphragm through the opening.
The flow path on the upstream side of the diaphragm is connected substantially perpendicular to the flow direction of the flow path on the downstream side of the diaphragm,
The flow path on the downstream side of the diaphragm is a substantially semi-cylindrical internal space having a curved surface facing the diaphragm,
A flow rate measuring device comprising: a strain gauge for detecting strain of the diaphragm; and an arithmetic unit for detecting the flow rate based on a detection value of the strain gauge. A space having an inner diameter larger than the flow path on the upstream side of the diaphragm is provided between the flow path on the upstream side of the diaphragm and the diaphragm,
The flow rate measuring device according to claim 1, wherein the outer diameter of the diaphragm is configured to match the inner diameter of the space. The flow path is provided with a flow rate adjusting valve for adjusting the flow rate of the fluid,
The flow rate measuring device according to claim 1, further comprising a control unit that controls the flow rate of the fluid by adjusting an opening of the flow rate adjustment valve based on a flow rate detected by the calculation unit. . The arithmetic unit based on the detection value of the strain gauge, and obtains a pressure difference ΔP between the pressure P _o of the fluid on the downstream side of the pressure P of the fluid in the upstream side of the diaphragm the diaphragm, The flow rate measuring device according to claim 1. The arithmetic unit calculates the flow rate Q by the following formula: Q = CA (2ΔP / ρ) ^1/2 (C: constant, A: opening area of the opening, ΔP: pressure P of the fluid upstream of the diaphragm and the above the differential pressure between the pressure P _o of the fluid on the downstream side of the diaphragm (ΔP = P-P o) , ρ: and calculating based on the density of the fluid), to any one of claims 1 to 4 The flow meter described. The flow rate measuring device according to claim 1, wherein the fluid is water vapor and ozone gas. The diaphragm is formed by a resin mold,
The flow rate measuring device according to claim 1, wherein the strain gauge is sealed in the diaphragm by a resin.

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