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WO2002033361A2 - Appareil et procede pour maintenir une perte de pression constante dans un compteur de gaz - Google Patents

Appareil et procede pour maintenir une perte de pression constante dans un compteur de gaz Download PDF

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Publication number
WO2002033361A2
WO2002033361A2 PCT/US2001/024607 US0124607W WO0233361A2 WO 2002033361 A2 WO2002033361 A2 WO 2002033361A2 US 0124607 W US0124607 W US 0124607W WO 0233361 A2 WO0233361 A2 WO 0233361A2
Authority
WO
WIPO (PCT)
Prior art keywords
pressure
inlet
actual
flow
outlet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2001/024607
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English (en)
Other versions
WO2002033361A3 (fr
Inventor
Paul Francis Grosshart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MKS Instruments Inc
Original Assignee
MKS Instruments Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by MKS Instruments Inc filed Critical MKS Instruments Inc
Publication of WO2002033361A2 publication Critical patent/WO2002033361A2/fr
Publication of WO2002033361A3 publication Critical patent/WO2002033361A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D7/00—Control of flow
    • G05D7/06—Control of flow characterised by the use of electric means
    • G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
    • G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
    • G05D7/0635—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
    • G01F25/10—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters
    • G01F25/15—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters specially adapted for gas meters
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
    • G01F25/10—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters
    • G01F25/17—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters using calibrated reservoirs

Definitions

  • the present disclosure relates generally to semiconductor processing equipment and, more particularly, to a flow controller for delivering contaminant-free, precisely metered quantities of process and purge gases to a semiconductor process chamber. Even more particularly, the present disclosure relates to an apparatus and method for maintaining a substantially constant pressure drop across a gas metering unit, such as a flow controller, to ensure precise metering of gases.
  • a gas metering unit such as a flow controller
  • the fabrication of a single semiconductor device can require the careful synchronization and precisely measured delivery of as many as a dozen gases to a process chamber.
  • Various recipes are used in the fabrication process, and many discrete processing steps where a semiconductor device is cleaned, polished, oxidized, masked, etched, doped, metalized, etc., may be required.
  • the steps used, their particular sequence and the materials involved all contribute to the making of particular devices.
  • wafer fabrication facilities are commonly organized to include areas in which chemical vapor deposition, plasma deposition, plasma etching, sputtering and other similar gas manufacturing processes are carried out.
  • the processing tools be they chemical vapor deposition reactors, vacuum sputtering machines, plasma etchers or plasma enhanced chemical vapor deposition, must be supplied with various process gases. Pure gases must be supplied to the tools in contaminant-free, precisely metered quantities.
  • the gases are stored in tanks, which are connected via piping or conduit to a gas box.
  • the gas box delivers contaminant-free, precisely metered quantities of pure inert or reactant gases from the tanks of the fabrication facility to a process tool.
  • the gas box, or gas metering system includes a plurality of gas paths having gas metering units, such as valves, pressure regulators and transducers, mass flow controllers and filters/purifiers. Each gas path has its own inlet for connection to separate sources of gas, but all of the gas paths converge into a single outlet for connection to the process tool. To insure that precisely metered quantities of gases are delivered to the process tool, there is a need for routine testing of the individual gas paths and metering units of the gas paths.
  • Such testing may comprise flow verification, and a metering unit under test may comprise a mass flow controller, for example.
  • a mass flow controller for example.
  • the present disclosure provides an apparatus for maintaining a substantially constant pressure drop across a gas metering unit to ensure precise metering of gases.
  • the apparatus includes an inlet valve controlling flow to an inlet of the metering unit, an inlet pressure measurement device connected to the inlet of the metering unit, and an outlet pressure measurement device connected to an outlet of the metering unit.
  • the apparatus also includes a controller that receives an actual inlet pressure from the inlet pressure measurement device, receives an actual outlet pressure from the outlet pressure measurement device, compares the actual inlet pressure to the actual outlet pressure to determine an actual pressure change, and causes the inlet valve to vary flow to the inlet of the metering unit if the actual pressure change varies from a predetermined initial pressure change. In this manner the disclosed apparatus maintains a substantially constant pressure drop across the metering unit.
  • the present disclosure also provides a gas delivery system including an mass flow controller (MFC) and an apparatus for maintaining a substantially constant pressure drop across the MFC.
  • MFC mass flow controller
  • the disclosure further provides a gas delivery system including an MFC, an apparatus for maintaining a substantially constant pressure drop across the MFC, and a flow verifier for verifying flow through the MFC.
  • a modular flow verifier incorporating an apparatus according to the present disclosure is disclosed as well.
  • the present disclosure provides a method of verifying flow through a metering unit under test, wherein the method maintains a substantially constant pressure drop across the metering unit during flow verification.
  • Fig. 1 is a schematic illustration of a gas metering system including a mass flow controller and an apparatus according to the present disclosure for maintaining a substantially constant pressure drop across the mass flow controller;
  • Fig. 2 is a flow chart illustrating a method according to the present disclosure of maintaining a substantially constant pressure change across a mass flow controller, as carried out by the apparatus of Fig. 1 ;
  • Fig. 3 is a schematic illustration of a gas metering system including a mass flow controller, a flow verifier, and an apparatus according to the present disclosure
  • Fig. 4 is a schematic illustration of a gas metering system including a mass flow controller, a flow verifier, and another apparatus according to the present disclosure.
  • Fig. 5 is a schematic illustration of a gas box system including a plurality of mass flow controllers, a flow verifier, and an apparatus according to the present disclosure.
  • the present disclosure provides an apparatus and method for maintaining a constant pressure drop across a metering unit.
  • the apparatus and method are particularly for use with gas metering systems for delivering contaminant-free, precisely metered quantities of process and purge gases to a semiconductor process chamber.
  • the presently disclosed apparatus and method ensure precise metering by maintaining a constant pressure drop across the metering unit.
  • a gas metering system 10 including a metering unit 12 and an apparatus 16 according to the present disclosure are schematically illustrated.
  • the metering unit can comprise a mass flow controller (MFC) 12, for example.
  • MFC mass flow controller
  • the gas metering system 10 is connected between a source of gas 90 and a process chamber 92, and a vacuum pump 94 is connected to the process chamber through a gate valve 96. During operation the vacuum pump 94 draws gas from the gas source 90, through the gas metering system 10 and into the process chamber 92.
  • the metering system 10 also includes system valves 20, 22 controlling flow to the process chamber 92 and the vacuum pump 94.
  • the apparatus 16 for maintaining a constant pressure drop across the MFC 12 includes a controller 40, and an inlet valve 42 controlling flow to an inlet 44 of the MFC 12, a pressure transducer 46 connected to the inlet 44 of the MFC 12, and a pressure transducer 48 connected to an outlet 28 of the MFC 12.
  • Suitable pressure measurement devices for use in the apparatus include Baratron ® brand manometers and pressure transducers available from MKS Instruments.
  • the MFC 12 and the apparatus 16 for maintaining a constant pressure drop across the MFC can be provided as a modular gas path, or stick. Such a modular gas stick would include the MFC 12 and the apparatus 16 mounted on a single gas manifold, for example.
  • suitable mass flow controllers are Mass- Flo ® brand controllers available from MKS Instruments of Andover, MA (http .//www.mksinst.com) .
  • a method according to the present disclosure of maintaining a substantially constant pressure change across a metering unit, e.g., the MFC 12, as carried out by the controller 40 of the apparatus 16 of Fig. 1, is shown.
  • the controller 40 first calculates an initial pressure change after an initialization period, as shown by "a" through “e” of Fig. 2.
  • the initial pressure change is calculated from initial pressure readings provided by the inlet pressure transducer 46 and the outlet pressure transducer 48.
  • the initial pressure readings can be taken after a suitable initialization period, e.g., 0.5 seconds, after the MFC 12 begins metering gas, to allow MFC pressures to stabilize.
  • the controller 40 then receives an actual inlet pressure from the inlet pressure transducer 46, receives an actual outlet pressure from the outlet pressure transducer 48, and compares the actual inlet pressure to the actual outlet pressure to determine an actual pressure change. If the actual pressure change varies from the predetermined initial pressure change, the controller 40 is programmed to cause the inlet valve 42 to vary flow to the inlet 44 of the MFC 12 until the actual pressure change substantially equals the initial pressure change as shown at "i" through “1” of Fig. 2. In particular, the controller 40 is programmed to cause the inlet valve 42 to decrease flow if the actual pressure change is greater than the initial pressure change, and to increase flow if the actual pressure change is less than the initial pressure change. Flow is increased or decreased until the actual pressure change substantially equals the initial pressure change.
  • FIG. 3 another gas metering system 11 is shown.
  • the system 11 of Fig. 3 is similar to the system 10 of Fig. 1, and elements that are the same have the same reference numeral.
  • the system 11 includes the MFC 12, the apparatus 16 according to the present disclosure, and a testing device 14 for testing the MFC 12.
  • the metering system 11 also includes a system valve 18 controlling flow from the source of gas 90.
  • the testing device comprises a flow verifier 14, which verifies flow through the MFC 12.
  • the apparatus 16 maintains a constant pressure drop across the MFC 12 to ensure a precise verification and, if necessary, calibration of the MFC.
  • the verifier 14 includes a vessel 24 having a predetermined volume, a first valve 26 controlling flow between an outlet 28 of the MFC 12 and an inlet 30 of the vessel 24, a second valve 32 controlling flow from an outlet 34 of the vessel 24, and a vessel pressure measurement device 36 communicating with the volume of the vessel.
  • a controller 38 of the flow verifier 14 utilizes the rate-of-rise method of flow verification.
  • the controller 38 includes a memory and a clock or timer and is programmed to first close the second valve 32 to stop flow from the outlet 34 of the vessel 24, then open the first valve 26 to allow flow between the outlet 28 of the MFC 12 and the inlet 30 of the vessel 24.
  • the controller 38 receives measurements of vessel pressure from the measurement device 36, receives measurements of time from its clock, and determines a rate of change in vessel pressure due to the gas flow.
  • the controller 38 determines an actual flow provided by the MFC 12 using the rate of change in vessel pressure and the known volume of the vessel 24.
  • the flow verifier 14 comprises a GBROR TM In situ Flow verifier provided by MKS Instruments of Andover, MA (http://www.mksinst.com).
  • the GBRORTM is a modular gas path, or stick, including the valves, the pressure vessel, the pressure transducer and the controller mounted on a manifold.
  • the GBROR TM is process transparent, i.e., operates between the normal processing steps of the gas delivery system and thus reduces processing tool down time.
  • FIG. 4 another apparatus 50 according to the present disclosure for maintaining a substantially constant pressure change across a mass flow controller is shown.
  • the apparatus 50 is operatively connected within a gas delivery system 52 also including a flow verifier 54.
  • the apparatus 50, gas delivery system 52 andilow verifier 54 of Fig. 4 are similar to the apparatus 16, gas delivery system 10 and flow verifier 14 of Fig. 3, and elements that are the same have the same reference numeral.
  • the apparatus 50 and the flow verifier 54 are preferably incorporated as a combined, in-situ, modular unit 56 having a single controller 58 for controlling both the flow verifier and the apparatus.
  • the unit 56 is preferably connected within the gas delivery system 52 such that the apparatus 50 and flow verifier 54 are process transparent, i.e., operate between normal processing steps such that the unit does not decrease the normal output of a semiconductor processor incorporating the gas delivery system.
  • the flow verifier 54 includes a by-pass valve 60 for connection between the outlet of the MFC 12 and the vacuum pump 94, which remains open when the verifier is not in use and closes when the verifier is in use.
  • the inlet valve 42 and the inlet pressure transducer 46 of the apparatus 50 are preferably provided as part of a pressure regulator 62 also including a controller 63.
  • a preferred pressure regulator 62 is a Type 640 pressure regulator available from MKS Instruments.
  • the controller 58 of the combined unit 56 is programmed to determine a desired MFC inlet pressure by adding a difference between the actual pressure drop across the MFC 12 and the initial pressure drop across the MFC 12 to the actual inlet pressure of the MFC.
  • the controller 58 then provides the desired inlet pressure to the controller 63 of the pressure regulator 62, which is programmed to compare the actual inlet pressure to the desired inlet pressure. If the actual inlet pressure is greater than the desired inlet pressure the controller 63 instructs the inlet valve 42 to reduce flow to the MFC 12 until the actual inlet pressure equals the desired inlet pressure. If the actual inlet pressure is less than the desired inlet pressure the controller 63 instructs the inlet valve 42 to increase flow until the actual inlet pressure equals the desired inlet pressure.
  • a gas delivery system 64 is shown that incorporates the in- situ, modular, combined unit 54 of Fig.4.
  • the gas delivery system 64 of Fig. 3 receives multiple gases, including both process gases and a purge gas, from sources 90a, 90b of gas and then precisely meters the gases to the process chamber 92.
  • the gas delivery system 64 includes gas sticks 66, and each stick includes an MFC 68, a first valve 70 positioned before an inlet 84 to the MFC and a second valve 72 positioned after an outlet 86 of the MFC.
  • the gas sticks 66 are separately connected to the sources 90a of process gas and provide controllable gas passageways so that a contaminant-free, precisely metered amount of a gas, or combination of gases, can be supplied from the gas delivery system to the process chamber 92.
  • the sticks 66 can also each be provided with other components for monitoring or controlling gases, such as filters, purifiers, and pressure transducers and controllers.
  • the system 64 also includes a first manifold 74 connecting the inlets 84 of the MFCs 68 of the sticks 66, and a second manifold 76 connecting the second valves 72 of the sticks 66.
  • the source 90b of purge gas is connected to the first manifold 74 through a first system valve 78, while the process chamber 92 is connected to the second manifold 76 through a second system valve 80 and the vacuum pump 94 is connected to the second manifold 76 through a third system valve 82.
  • the first manifold 74 selectively provides flow to one of the sticks 66 from the source 90b of purge gas, while the second manifold 76 selectively provides flow from one of the sticks 66 to either the process chamber 92 or the vacuum pump 94.
  • the manifolds 74, 76 can comprise chained pneumatic valves, for example, for selectively providing flow to one of the sticks 66 while isolating the remaining sticks 66.
  • the pressure regulator 62 of the unit 56 is connected between the source 90b of purge gas and the first manifold 74, and the by-pass valve 60 of the unit 56 is connected between the second manifold 76 and the vacuum pump 94. Accordingly, purge gas is used to verify the flow of each gas stick 66 in between normal processing steps. By using the manifolds 74, 76 to provide flow to one stick at a time, the flow verification unit 56 can verify flow and, if necessary, calibrate each of the sticks 66 individually.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Measuring Volume Flow (AREA)
  • Flow Control (AREA)

Abstract

L'invention concerne un appareil conçu pour maintenir une perte de pression sensiblement constante dans un compteur de gaz afin d'en assurer un fonctionnement précis. L'appareil comporte une soupape d'admission régulant le flux vers une entrée du compteur, un dispositif de mesure de la pression d'admission relié à l'entrée du compteur, et un dispositif de mesure de pression de sortie relié à une sortie du compteur. L'appareil comporte en outre un régulateur qui reçoit une pression d'admission réelle du dispositif de mesure de pression d'admission, une pression de sortie réelle du dispositif de mesure de la pression de sortie. Le contrôleur compare alors la pression d'admission réelle à la pression de sortie réelle afin de déterminer un changement de pression réel et agit sur la soupape d'admission pour faire varier le flux vers l'entrée du compteur, dans le cas où le changement de pression réel varie par rapport à un changement de pression initial prédéterminé. Ainsi, l'appareil selon l'invention, maintient une perte de pression sensiblement constante dans le compteur.
PCT/US2001/024607 2000-10-13 2001-08-06 Appareil et procede pour maintenir une perte de pression constante dans un compteur de gaz Ceased WO2002033361A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US68757100A 2000-10-13 2000-10-13
US09/687,571 2000-10-13

Publications (2)

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WO2002033361A2 true WO2002033361A2 (fr) 2002-04-25
WO2002033361A3 WO2002033361A3 (fr) 2002-08-01

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1797489A4 (fr) * 2004-07-09 2008-07-30 Celerity Inc Procédé et système de mesure d'écoulement et validation d'une unité de commande d'écoulement massive
WO2009117169A1 (fr) * 2008-03-18 2009-09-24 Mks Instruments, Inc. Vérificateur de débit massique de haute précision avec entrées multiples
WO2012146336A1 (fr) * 2011-04-29 2012-11-01 Horiba Europe Gmbh Dispositif de mesure d'un débit de carburant et dispositif de calibrage à cet effet
CN104764510A (zh) * 2015-04-23 2015-07-08 江苏博克斯自动化控制工程有限公司 一种全自动直插式热式气体质量流量计标定系统及其应用
WO2018008420A1 (fr) * 2016-07-05 2018-01-11 株式会社フジキン Dispositif de régulation de débit, procédé d'étalonnage du débit d'un dispositif de régulation de débit, dispositif de mesure de débit et procédé de mesure de débit utilisant ce dispositif de mesure de débit

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59225411A (ja) * 1983-06-06 1984-12-18 Tokyo Keiki Co Ltd デイジタル弁制御装置
DE3725312A1 (de) * 1987-07-30 1989-02-09 Jiri Hokynar Steuergeraet fuer fluidfluss
US5190068A (en) * 1992-07-02 1993-03-02 Brian Philbin Control apparatus and method for controlling fluid flows and pressures
US6074691A (en) * 1997-06-24 2000-06-13 Balzers Aktiengesellschaft Method for monitoring the flow of a gas into a vacuum reactor
JPH11259140A (ja) * 1998-03-13 1999-09-24 Kokusai Electric Co Ltd 流量制御装置
US6152162A (en) * 1998-10-08 2000-11-28 Mott Metallurgical Corporation Fluid flow controlling

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1797489A4 (fr) * 2004-07-09 2008-07-30 Celerity Inc Procédé et système de mesure d'écoulement et validation d'une unité de commande d'écoulement massive
US7757554B2 (en) 2005-03-25 2010-07-20 Mks Instruments, Inc. High accuracy mass flow verifier with multiple inlets
WO2009117169A1 (fr) * 2008-03-18 2009-09-24 Mks Instruments, Inc. Vérificateur de débit massique de haute précision avec entrées multiples
CN101978245B (zh) * 2008-03-18 2013-08-21 Mks仪器公司 具有多个入口的高精度质量流量检验器
WO2012146336A1 (fr) * 2011-04-29 2012-11-01 Horiba Europe Gmbh Dispositif de mesure d'un débit de carburant et dispositif de calibrage à cet effet
DE102011100029C5 (de) * 2011-04-29 2016-10-13 Horiba Europe Gmbh Vorrichtung zum Messen eines Kraftstoffflusses und Kalibriervorrichtung dafür
US9482571B2 (en) 2011-04-29 2016-11-01 Horiba Europe Gmbh Device for measuring a fuel flow and calibrating device therefor
CN104764510A (zh) * 2015-04-23 2015-07-08 江苏博克斯自动化控制工程有限公司 一种全自动直插式热式气体质量流量计标定系统及其应用
WO2018008420A1 (fr) * 2016-07-05 2018-01-11 株式会社フジキン Dispositif de régulation de débit, procédé d'étalonnage du débit d'un dispositif de régulation de débit, dispositif de mesure de débit et procédé de mesure de débit utilisant ce dispositif de mesure de débit
JP2018004499A (ja) * 2016-07-05 2018-01-11 株式会社フジキン 流量制御機器、流量制御機器の流量校正方法、流量測定機器および流量測定機器を用いた流量測定方法

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