Mass flow control based on micromotor device

Abstract

This document discloses embodiments of a mass flow control device, a system integrating the mass flow control device, and a method of using the mass flow control device. In one embodiment, the mass flow control device includes: a flow regulating valve configured to regulate gas flow in a gas flow channel; a sensor device, such as a micro-electro-mechanical system (MEMS) device, configured to generate a signal in response to the state of the gas flow; and a processing device operatively coupled to the flow regulating valve and the sensor device to control the flow regulating valve based on signals received from the sensor device.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to methods and apparatus for controlling the flow rate of gases. Background Technology

[0002] Controlling gas flow rates is a common challenge in manufacturing systems. In some manufacturing systems, process gases (i.e., gases used during semiconductor manufacturing processes) and / or cleaning gases (i.e., gases used in cleaning equipment and / or chambers used in manufacturing electronic devices) may have precise delivery targets including high-quality flow rates (i.e., 500 standard liters per minute or more) and the ability to precisely control low flow rates (i.e., 10 standard liters per minute or less). Known manufacturing systems often use one or more mass flow controllers (MFCs) to measure and control the mass flow rate of process gases.

[0003] Each type of MFC (e.g., thermal MFC, pressure-based MFC, decay rate-based MFC, etc.) imposes one or more limitations depending on the application using the MFC. For example, thermal MFCs utilize thermal sensors to measure flow and control needle valves to regulate flow direction in the downstream processing chamber. The feedback from such thermal sensors is very slow, resulting in a slow response rate for the MFC (on the order of 100 milliseconds or longer). This makes thermal MFCs impractical for manufacturing applications requiring precise gas control and timing. Summary of the Invention

[0004] Some embodiments of this disclosure relate to apparatus, systems, and methods for regulating mass flow control based on micro-electromechanical (MEMS) devices. In one aspect, a mass flow control apparatus includes: a flow regulating valve configured to regulate gas flow in a gas flow channel; a sensor device (e.g., a MEMS device) configured to generate a signal in response to the state of the gas flow; and a processing device operatively coupled to the flow regulating valve and the sensor device, wherein in some embodiments, the processing device is configured to control the flow regulating valve based on signals received from the sensor device.

[0005] In another aspect of this invention, a system includes: a processing chamber; a gas flow channel arranged to deliver gas from a gas source into the processing chamber; a flow control valve configured to regulate gas flow in the gas flow channel; one or more microelectromechanical devices (MEMS); and a processing device operatively coupled to the flow control valve and the MEMS devices. In some embodiments, the one or more MEMS devices are configured to generate a gas flow signal in response to the state of gas flow in the gas flow channel. In some embodiments, the processing device is configured to control the flow control valve based on signals received from the one or more MEMS devices.

[0006] In another aspect of this invention, a method includes: sending a control signal to a flow control valve configured to regulate mass flow rate in a flow channel; receiving a feedback signal from a MEMS device; calculating an updated control signal based on the feedback signal from the MEMS device; and sending the updated control signal to the flow control valve. In some embodiments, the MEMS device is located downstream of the flow control valve. In some embodiments, the feedback signal indicates the state of the mass flow rate. Attached Figure Description

[0007] This disclosure is illustrated in the accompanying drawings by way of example and not limitation, in which the same reference numerals indicate similar elements. It should be noted that in this context, different references to "an" or "one" embodiments are not necessarily the same embodiments, and such references imply at least one.

[0008] Figure 1 An exemplary system comprising a processing chamber, a gas source, and a flow control device, according to an embodiment of the present disclosure, is shown.

[0009] Figure 2 An exemplary flow control device according to an embodiment of the present disclosure is shown.

[0010] Figure 3A A top view of an exemplary MEMS device according to an embodiment of the present disclosure is shown.

[0011] Figure 3B A side view of an exemplary MEMS device according to an embodiment of this disclosure is shown.

[0012] Figure 3C A stand-alone sensing element of an exemplary MEMS device according to an embodiment of this disclosure is shown.

[0013] Figure 4 An exemplary flow control device having multiple sensor devices connected in series is shown according to an embodiment of the present disclosure.

[0014] Figure 5 An exemplary flow control device utilizing a flow ratio controller according to an embodiment of the present disclosure is shown.

[0015] Figure 6 A method for regulating gas flow in a gas flow channel according to an embodiment of the present disclosure is shown.

[0016] Figure 7 A block diagram illustrating a computer system used according to an embodiment of this disclosure. Detailed Implementation

[0017] The embodiments described herein relate to mass flow control devices, systems incorporating mass flow control devices into gas delivery systems (e.g., for processing chambers), and methods of regulating gas flow in a gas flow channel using mass flow control devices. In some embodiments, the mass flow control device includes: a flow regulator including a flow control valve for regulating gas flow in a gas flow channel; a sensor device for generating a signal in response to gas flow conditions; and a processing device operatively coupled to both the flow regulator and the sensor device. The sensor device may be a MEMS device with a stand-alone sensing element directly disposed in the flow path of the gas flow channel, which transmits its signal to the processing device. The processing device then calculates one or more parameters of the gas flow, such as temperature, pressure, gas velocity, and gas flow rate, and actuates the flow control valve based on the signal from the MEMS device to achieve a target flow rate (by increasing or limiting gas flow).

[0018] Typically, precise control of the flow rate of the process gas used in manufacturing processes is advantageous for better process control and to allow for the satisfaction of precise process constraints. The low transient response rate of existing MFCs, typically on the order of 100 microseconds or larger, is unsuitable for applications requiring precise control of gas dosage, such as the delivery of small amounts of gas as well as the continuous delivery of pulses (“mass flow pulses”) of one or more gases with pulse widths on the order of 100 milliseconds or smaller.

[0019] Embodiments of this disclosure advantageously overcome the limitations of current MFCs by utilizing MEMS devices directly within the gas flow path to provide fast (i.e., transient response of less than about 1 millisecond) and accurate flow feedback. Compared to conventional MFCs, processing devices operatively coupled to MEMS devices (such as...) Plug-in module ( A plug-in module (EPM) can be used to control an MFC or a standalone actuable valve more quickly based on fast flow feedback. Although various embodiments may utilize a MEMS device as the sole source of feedback, flow feedback from an MFC device can also be advantageously used in conjunction with MEMS feedback, for example, for calibration or verification purposes (e.g., to ensure consistency between measured signals).

[0020] In addition to flow feedback, MEMS devices can be advantageously used to provide rapid and accurate temperature measurement at any location on the gas supply line, including at the source, near the valve, near the inlet (i.e., delivery point) leading to the processing chamber, or inside the processing chamber. Temperature measurements can be monitored in real time by a processing device that can then send power output commands to heating units at different locations on the gas supply line.

[0021] Some implementations advantageously utilize one or more MEMS devices at various locations along the gas supply line, which can be used to account for time delays caused by the distance between the flow control valve and the MEMS device. Some implementations also advantageously utilize multiple MEMS devices in a system architecture including a flow ratio controller, wherein multiple MEMS devices configured in parallel and series are used along various flow paths. For example, multiple sensors in series can be used to address drift in individual sensors, as well as for calibration and diagnostic purposes.

[0022] Some implementations also advantageously utilize one or more MEMS devices in the pulsed gas delivery system to rapidly and continuously deliver precise pulses of one or more different gases, wherein the pulse width is on the order of milliseconds or less (e.g., 20-millisecond pulses).

[0023] Several embodiments described herein relate to MFCs or components thereof for limiting the flow rate of gases used in manufacturing systems. However, it should be understood that the embodiments described herein are also applicable to purposes other than manufacturing, such as constructing ventilation systems and ventilators for medical applications.

[0024] Figure 1A system 100 according to an embodiment of this disclosure is depicted, comprising a chamber 101 (e.g., a semiconductor processing chamber), a gas source 160, and flow control equipment 200. The chamber 101 can be used for processing in which a corrosive plasma environment is provided. For example, the chamber 101 may be a chamber for a plasma etcher or plasma etching reactor, a plasma cleaner, etc. In alternative embodiments, other processing chambers that may or may not be exposed to a corrosive plasma environment may be used. Some examples of chamber components include chemical vapor deposition (CVD) chambers, physical vapor deposition (PVD) chambers, atomic layer deposition (ALD) chambers, ion-assisted deposition (IAD) chambers, etching chambers, or other types of processing chambers. In some embodiments, the chamber 101 may be any chamber used in an electronic device manufacturing system.

[0025] In one embodiment, chamber 101 includes a chamber body 102 enclosing an internal volume 106 and a nozzle 130. The nozzle 130 may include a nozzle base and a nozzle gas distribution plate. Alternatively, the nozzle 130 may be replaced by a cap and nozzle in some embodiments, or by multiple pie-shaped nozzle compartments and a plasma generation unit in other embodiments. The chamber body 102 may be made of aluminum, stainless steel, or other suitable materials such as titanium. The chamber body 102 typically includes sidewalls 108 and a bottom 110.

[0026] The outer liner 116 may be disposed adjacent to the sidewall 108 to protect the chamber body 102. The outer liner 116 may be manufactured to include one or more holes. In one embodiment, the outer liner 116 is made of alumina.

[0027] The vent 126 may be defined within the chamber body 102 and may be coupled to the internal volume 106 to the pump system 128. The pump system 128 may include one or more pumps and throttle valves for evacuating and regulating the pressure of the internal volume 106 of the chamber 101.

[0028] A gas source 160 may be coupled to chamber 101 to supply process and / or cleaning gas to internal volume 106 via supply line 112 through nozzle 130. A flow control device 200 may be coupled to both gas source 160 and chamber 101. The flow control device 200 can be used to measure and control the gas flow from gas source 160 to internal volume 106. An exemplary flow control device 200 is described below regarding... Figure 2More detailed description. In some embodiments, one or more gas sources 160 may be coupled to chamber 101 to supply gas to internal volume 106. In this embodiment, one or more flow control devices 200 may be coupled to each gas source 160 and chamber 101. In other embodiments, a single flow control device 200 may be coupled to one or more gas sources 160. In some embodiments, the flow control device 200 may include a flow ratio controller to control the gas flow to chamber 101 (e.g., through one or more supply lines 112) or to other processing chambers.

[0029] Nozzle 130 may be supported on the sidewall 108 of chamber body 102. Nozzle 130 (or cap) may be opened to allow access to the internal volume 106 of chamber 101 and may provide a seal to chamber 101 when closed. Gas source 160 may be coupled to chamber 101 to supply processing and / or cleaning gas through nozzle 130 or cap and nozzle (e.g., through orifices in nozzle or cap and nozzle) to the internal volume 106. Nozzle 130 may be used in processing chambers for dielectric etching (etching dielectric materials). Nozzle 130 may include a gas distribution plate (GDP) and may have multiple gas delivery orifices 132 (also referred to as channels) throughout GDP. Nozzle 130 may be formed of a metal or alloy plate protected by a multilayer protective coating as described herein. The metal or alloy plate may be made of aluminum, an aluminum alloy, or another metal or metal alloy. The nozzle 130 can be formed in which GDP is bonded to an aluminum base or an anodized aluminum base. GDP can be made of Si or SiC, and can be ceramic, such as Y₂O₃, Al₂O₃, or Y₃Al₅O₃. 12 (YAG) etc.

[0030] For processing chambers used for etching conductive materials, a cap can be used instead of a nozzle. The cap may include a central nozzle fitted into a central aperture. The cap may be ceramic, such as Al₂O₃, Y₂O₃, YAG, or a ceramic compound comprising a solid solution of Y₄Al₂O₉ and Y₂O₃-ZrO₂. The nozzle may also be ceramic, such as Y₂O₃, YAG, or a ceramic compound comprising a solid solution of Y₄Al₂O₉ and Y₂O₃-ZrO₂.

[0031] Examples of processing gases that can be used to process the substrate in processing chamber 101 include halogen-containing gases such as C2F6, SF6, SiCl4, HBr, NF3, CF4, CHF3, CH2F3, F, NF3, Cl2, CCl4, BCl3, and SiF4, and other gases such as O2 or N2O. The flow rate of any of these gases can be measured and adjusted by flow control device 200. Remote plasma can be formed from any of these and / or other processing gases and subsequently delivered to chamber 101 via supply line 112 and flow control device 200. Thus, remote plasma can be composed of C2F6, SF6, SiCl4, HBr, NF3, CF4, CHF3, CH2F3, F, NF3, Cl2, CCl4, BCl3, and SiF4, and other gases such as O2 or N2O. Examples of carrier gases include N2, He, Ar, and other gases that are inert to the processing gases (e.g., non-reactive gases).

[0032] A substrate support assembly 148 is disposed below the nozzle 130 within the internal volume 106 of the chamber 101. The substrate support assembly 148 holds the substrate 144 during processing. A ring (e.g., a single ring) may cover a portion of the electrostatic chuck 150 and protect the covered portion from plasma exposure during processing. In one embodiment, the ring may be silicon or quartz. An inner liner may be coated around the periphery of the substrate support assembly 148. The inner liner may be a halogen-resistant material, such as Al2O3, Y2O3, YAG, ceramic compounds including solid solutions of Y4Al2O9 and Y2O3-ZrO2, other rare-earth-containing or non-rare-earth-containing ceramic materials, or combinations thereof. In one embodiment, the inner liner may be made of the same material as the outer liner 116.

[0033] In some embodiments, one or more sensor devices 170 may be disposed within the internal volume 106. For example, one or more sensor devices 170 may be located near the nozzle 130 (e.g., within 10 cm of the nozzle 130). As another example, one or more sensor devices may be located near the substrate 144 (e.g., within 10 cm of the substrate 144), and these sensor devices may be used to monitor the state near the reaction site.

[0034] In one embodiment, the substrate support assembly 148 includes a base 152 supporting an electrostatic chuck 150. The electrostatic chuck 150 further includes a thermally conductive base and an electrostatic disk bonded to the thermally conductive base by a bonding element, which in one embodiment may be a siloxane bonding element. The thermally conductive base and / or the electrostatic disk of the electrostatic chuck 150 may include one or more optional embedded heating elements, embedded thermal isolators, and / or conduits to control the lateral temperature distribution of the substrate support assembly 148. The electrostatic disk may further include a plurality of gas channels, such as grooves, mesas, and other surface features, that can be formed in the upper surface of the electrostatic disk. The gas channels may be fluidly coupled to a source of heat transfer (or back-side) gas (such as helium) via holes drilled in the electrostatic disk. In operation, back-side gas can be supplied to the gas channels under controlled pressure to enhance heat transfer between the electrostatic disk and the supported substrate 144. The electrostatic chuck 150 may include at least one clamping electrode controlled by a clamping power supply.

[0035] Figure 2 A flow control device 200 according to an embodiment of this disclosure is depicted. The flow control device 200 can be configured to measure and control the mass flow rate of process gases and / or cleaning gases used in a manufacturing system, and can therefore be considered a type of MFC. The flow control device 200 can be coupled to a gas source 160 and a chamber 101 via a gas flow channel 240. The gas flow channel can correspond to... Figure 1 Supply line 112. In some embodiments, the flow control device 200 may be integrated into a flow ratio controller or a pulse mass flow system.

[0036] In some embodiments, the flow control device 200 may include at least a flow regulator 210, a sensor device 220, and a processing device 230. Gas from the gas source 160 flows through a flow path 242 (defined by a gas flow channel 240), through the flow regulator 210, and into the chamber 101. In other embodiments, the gas flow channel 240 may terminate somewhere other than the chamber 101. For example, the gas flow channel 240 may deliver gas to an open environment (e.g., an exhaust system) or a closed environment (e.g., a building or vehicle ventilation system).

[0037] In some embodiments, the flow regulator 210 is configured to restrict gas flow through the flow path 242 and may include one or more flow regulating valves, each of which may be an actuable valve, such as, for example, a solenoid valve, a piezoelectric valve, or a power valve. In some embodiments, the flow regulator includes components other than valves, such as flow or temperature sensing components. In some embodiments, the flow regulator 210 is used as an MFC, such as a heat-based MFC, a pressure-based MFC, or a decay rate-based MFC.

[0038] In some embodiments where the flow regulator 210 is used as a heat-based MFC, the flow regulator 210 includes a capillary bypass channel branching off from the gas flow channel 240. Temperature sensors at the beginning and end of the capillary are used to calculate (e.g., by the processing device 230 or an onboard processing device) a temperature increment proportional to the gas flow rate.

[0039] In some embodiments where the flow regulator 210 is used as a pressure-based MFC, the flow regulator 210 includes two pressure transducers upstream and downstream of the flow control valve and temperature sensor. The gas flow rate is proportional to the product of the temperature and the squared difference between the upstream and downstream pressures.

[0040] In some embodiments where the flow regulator 210 is used as an attenuation rate-based MFC, the flow regulator 210 includes a valve for controlling gas flow into a reservoir of a predetermined volume, and a pressure sensor for measuring the attenuation pressure in the reservoir. The gas flow rate is proportional to the rate of pressure change.

[0041] In some embodiments, the sensor device 220 is disposed downstream of the flow regulator 210. The sensor device 220 may be part of the flow regulator 210 (e.g., a flow control valve adjacent to the flow regulator 210), may be near the flow regulator 210 (e.g., within 10 cm of the flow regulator 210), may be near the inlet of the chamber 101 or the nozzle 130 (e.g., within 10 cm of the inlet), or may be within the chamber 101 (e.g., within 10 cm of the inlet). Figure 1 The diagram shows sensor device 170, which may be the same as or similar to sensor device 220.

[0042] In some embodiments, sensor device 220 includes a MEMS device 222 that may be configured to generate one or more signals in response to the state of gas flow. For example, MEMS device 222 may be configured to generate one or more signals indicating gas temperature or gas flow rate. Exemplary MEMS devices are described in more detail below with reference to FIG3. In some embodiments, sensor device 220 (and / or other sensor devices described herein) is any device having a transient response of less than 1 millisecond and may be a MEMS device or a non-MEMS device. In some embodiments, sensor device 220 is mounted to gas flow channel 240 such that MEMS device 222 is directly inserted into flow path 242. Sensor device 220 is coupled to gas flow channel such that a seal is formed to prevent gas leakage. In some embodiments, sensor device 220 includes a mounting plate to which MEMS device 222 is secured via a seal (e.g., a metal seal).

[0043] In some embodiments, processing device 230 includes a central processing unit (CPU), microcontroller, programmable logic controller (PLC), system-on-a-chip (SoC), server computer, or other suitable type of computing device. Processing device 230 may be configured to execute programmed instructions relating to the operation of flow regulator 210. Processing device 230 receives feedback signals from sensor device 220 (and, optionally, from flow regulator 210) and calculates the temperature, flow rate, and / or other parameters of the gas flow. Processing device 230 further sends control signals to flow regulator 210 based on the received feedback signals. In some embodiments, processing device 230 is configured for high-speed feedback processing and may include, for example, an EPM. In some embodiments, processing device is configured to perform a processing recipe, or one or more steps of a processing recipe, for a manufacturing process using chamber 101. For example, a recipe may specify a gas flow at a specific time, for a specific duration, or for a specific gas at a specific flow rate. As another example, a recipe may specify a pulse of one or more gases.

[0044] Figure 3A and Figure 3B Top and side views of an exemplary MEMS device 300 according to embodiments of the present disclosure are shown, which is manufactured using semiconductor manufacturing techniques familiar to those skilled in the art. The MEMS device 300 can be used with... Figure 2The MEMS device 222 described is identical or similar. The overall dimensions of the MEMS device 300 can be characterized by the following items: length (L) from about 2 mm to about 10 mm, width (W) from about 1 mm to about 5 mm, and thickness (T) from about 0.1 mm to about 1 mm. The MEMS device 300 includes an elongated support structure 302 having a substantially flat shape. The elongated support structure 302 may be formed of an insulating material or a semiconductor, such as silicon, silicon with one or more oxide layers formed thereon, or any other suitable material. The elongated support structure 302 may have a tapered shape, which can improve its aerodynamic properties. The tapered region may further define a cavity 306 on which freestanding sensing elements (such as nanowires 308) are suspended.

[0045] Electrodes 304 are shown disposed on the surface of an elongated support structure 302, extending from a flat end of the elongated support structure 302 to the nanowire 308. Electrodes 304 may be formed of one or more conductive metals. The electrodes may serve as electrical contacts to which one or more devices (e.g., processing device 230) are operatively coupled. In some embodiments, a portion of the electrode 304 may be encapsulated or formed within the elongated support structure 302 to protect the electrode 304 from corrosion.

[0046] Figure 3C An enlarged view of a nanowire 308 suspended between two electrodes 304 is shown. As used herein, the term "nanowire" refers to a conductive body having at least two dimensions of less than 1 micrometer. In some embodiments, the nanowire 308 is formed of the same conductive material as the electrodes 304, such as platinum. For example, the nanowire 308 may be formed by depositing a metal (e.g., platinum) onto an elongated support structure 302 and selectively etching the elongated support structure 302, thereby causing the freestanding nanowire 308 to be suspended on a cavity 306. In some embodiments, the nanowire 308 may be a single continuous filament, but may also be formed from nanoparticles or nanotubes arranged to form a conductive route. Other continuous or discontinuous structures may be used, provided that impedance measurements across the line are permitted.

[0047] Nanowire 308 is fabricated to have a length (L) greater than its diameter or width / thickness. w The nanowires 308 are sized such that they can deflect when exposed to low and high velocity gas flows. In some embodiments, L w The length is less than 1 millimeter, for example, from about 1 micrometer to about 500 micrometers, or from about 10 micrometers to about 200 micrometers. In some embodiments, L wThe nanowire 308 may be approximately 10 to approximately 100,000 times larger than its diameter or width / thickness. In some embodiments, the nanowire 308 may have a circular or rectangular cross-section having a diameter or thickness / width of approximately 50 nanometers to approximately 500 nanometers. Those skilled in the art will recognize that other sizes may be available.

[0048] In some embodiments, the MEMS device 300 may be configured to provide multiple sensor modes with different sensitivities along different dimensions. For example, the MEMS device 300 may be configured for a constant current anemometer (CCA), wherein a fixed current is flowed through nanowires 308 to raise the temperature of nanowires 308, thereby increasing resistance. During operation, the flowing gas above the wires carries away heat from the nanowires 308 through convection, and the resistance will reach a steady state under constant current and constant gas velocity. An increase or decrease in gas velocity will respectively cause a decrease or increase in the resistance of nanowires 308, thereby allowing the measured voltage output to be correlated with the gas flow rate.

[0049] As another example, the MEMS device 300 can be configured for elastic filament velocimetry (EFV). The gas velocity can be correlated with the strain in the nanowire 308 due to the deflection caused by the gas flow. In this operation, a small current can flow through the nanowire 308, resulting in negligible heating. During operation, the gas flow deflects the nanowire 308, thereby causing internal stress that changes the resistance of the nanowire 308. This change in resistance can be correlated with the gas flow rate.

[0050] In some embodiments, nanowires 308 may be incorporated into a MEMS device 300, wherein two or more nanowires have separate electrode pairs, each of which can be used independently to perform CCA or EFV. In some embodiments, the two or more nanowires may be oriented in a non-collinear orientation.

[0051] For reference Figure 4 and Figure 5 , Figure 4 and Figure 5 A variation of the flow control device 200 is shown. Figure 4 An exemplary flow control device 400 having a plurality of sensor devices 220 connected in series, according to an embodiment of the present disclosure, is shown. (This is related to...) Figure 2The sensor devices 220 described as identical or similar are arranged in series at various locations along the gas flow path 240. In some embodiments, two, three, or more sensor devices 220 may be present. Sensor devices 220 located near the flow regulator 210, downstream of the flow regulator 210, and near the chamber 101 may be used by the processing device 230 to verify the flow rate at various locations in the gas flow path 240, for example, to resolve drift or malfunction of one or more sensor devices 220. The processing device 230 may also utilize signals from sensor devices 220 at various distances from the flow regulator 210 to resolve signal delays when controlling the flow regulator 210. In some embodiments, additional sensor devices 220 may be present, for example, upstream of the flow regulator 210. In some embodiments, two or more sensor devices may be used for exhaust / foreline flow rate measurement. For example, one or more sensor devices near the gas source 160 and downstream of the flow regulator 210 can be used by the processing device 230 to compare the total flow rate from upstream near the gas source 160 with the flow rate downstream (e.g., exhaust / fore-line flow rate) in order to calculate the reaction rate or efficiency.

[0052] Figure 5 An exemplary flow control device 500 utilizing a flow ratio controller 510 according to an embodiment of the present disclosure is shown. Processing device 230 and connection to processing device 230 are described. Figure 5 The figures are omitted to avoid obscuring the overall composition. The flow ratio controller 510 may be configured to divide the gas flow from the input flow path 520 into two or more separate flow paths 522 and 524, respectively defined by gas flow channels 532 and 534. Sensor devices 220 are arranged side-by-side (or otherwise configured) at various locations along the flow paths 522 and 524 to monitor the state of the gas flow. Each of the sensor devices 220 generates a signal indicating the flow rate and / or temperature. The signals from the sensor devices 220 in the two or more flow paths are provided to a processing device 230, which uses these signals to determine the current ratio of gas delivered to these respective flow paths. The flow ratio controller 510 may then adjust the amount of gas delivered to each flow path to achieve a target flow ratio. In some embodiments, more than one gas flow may be received by the flow ratio controller 510, and these gas flows may be mixed and routed through flow paths 522 and 524 or additional flow paths.

[0053] Figure 6A method 600 for regulating mass flow rate in a flow channel according to an embodiment of this disclosure is shown. Some or all of the operations of method 600 may be performed, for example, by a processing device of a flow control apparatus (such as processing device 230 of flow control apparatus 200). Some or all of the operations may also be performed by an MFC or another suitable device.

[0054] At block 610, a processing device (e.g., processing device 230) sends a control signal to a flow control valve (e.g., the flow control valve of flow regulator 210) configured to regulate the mass flow rate in a flow passage (e.g., gas flow passage 240). For example, the signal may indicate a flow threshold or setpoint for the flow control valve, which actuates the flow control valve to achieve a target flow rate in the gas flow passage. In some embodiments, the flow control valve includes an actuable valve, such as a piezoelectric valve, a solenoid valve, or a motorized valve. The mass flow rate may include the flow rate of a gaseous substance, a non-gaseous substance (e.g., an evaporating precursor), or a combination thereof. It will be understood that any of the embodiments described herein can be generally used for mass flow rates and is not limited to the flow rate of gaseous substances.

[0055] At block 620, a feedback signal from a sensor device (e.g., MEMS device 222) is received by a processing device. The sensor device can be a MEMS device or any other device with a transient response of 1 millisecond or less. In some embodiments, the feedback signal indicates the state of gas flow (e.g., gas temperature, gas velocity or flow rate, gas pressure, etc.). In some embodiments, the MEMS device is located downstream of a flow control valve (e.g., as shown in the image). Figure 2 (As depicted in the image). In some embodiments, the MEMS device is positioned upstream of the flow control valve (e.g., as shown in the image). Figure 4 (As depicted in the image). In some embodiments, the MEMS device includes a stand-alone sensing element (e.g., nanowire 308) that is directly disposed in the flow path of the gas flow channel (e.g., flow path 242).

[0056] In some implementations, more than one MEMS device may be used (e.g., such as...). Figure 4 and Figure 5 (As depicted in the image), the processing device can receive multiple signals from these MEMS devices. In some embodiments, the transient response of the feedback signal generated by any one of the one or more MEMS devices is less than 1 millisecond.

[0057] In some embodiments, the flow control valve is part of an MFC containing one or more sensor devices. For example, in some embodiments, the flow control valve is part of a thermally based MFC, a pressure-based MFC, or a decay rate-based MFC. In some embodiments, the processing device receives signals from one or more sensor devices associated with the MFC device. Although such signals typically have transient response rates on the order of 100 milliseconds or longer, the processing device can compare these signals with signals received by the MEMS device, for example, for verification or calibration purposes.

[0058] At block 630, the processing device calculates an updated control signal based on feedback signals from the MEMS devices. In some embodiments, the processing device calculates mass flow temperature, mass flow pressure, mass velocity, or mass flow rate, or other parameters based on the feedback signals. In some embodiments, the turn-down ratio of the mass flow rate (i.e., the highest measurable flow rate divided by the lowest measurable flow rate) is at least 200. In some embodiments, the updated control signal corresponds to a new threshold or setpoint for the flow control valve to ensure that the target flow rate is achieved. For example, if the calculated flow rate is greater than the target, the updated control signal corresponds to a new threshold or setpoint to further restrict the flow through the flow control valve. In some embodiments, if multiple signals are received from multiple MEMS devices, the processing device may, for example, calculate the difference between the average signal and / or the detected signal from the multiple signals. This difference may indicate a fault or drift in one of the MEMS devices.

[0059] At block 640, the processing device sends an updated control signal to the flow control valve. In some embodiments, the processing device generates one or more pulse control signals based on feedback signals from the MEMS device. For example, the pulse control signals may cause the flow control valve to generate gas flow pulses with pulse widths of, for example, less than 50 milliseconds, less than 40 milliseconds, less than 30 milliseconds, or less than 20 milliseconds. In some embodiments, method 600 is performed in several cycles, for example, as part of a processing scheme for executing a manufacturing system.

[0060] For the sake of simplicity, the methods of this disclosure are depicted and described as a series of actions. However, the actions according to this disclosure can occur in any order and / or simultaneously, and other actions are not presented or described herein. Furthermore, not all actions shown are required to implement the methods according to the disclosed subject matter. Moreover, those skilled in the art will understand and recognize that the methods can alternatively be represented as a series of interrelated states via state diagrams or events. Furthermore, it should be understood that the methods disclosed in this specification can be stored on an article of writing to facilitate the transfer and transmission of instructions for performing such methods to a computing device. As used herein, the term "article of writing" is intended to encompass a computer program accessible from any computer-readable device or storage medium.

[0061] Figure 7 A graphical representation of a machine in an exemplary form of computer system 700 is shown, wherein an executable set of instructions (e.g., for causing the machine to perform any or more methods discussed herein) is provided. In alternative embodiments, the machine may be connected (e.g., network-connected) to other machines in a LAN, WAN, intranet, extranet, or the Internet. The machine may operate as a server or client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The machine may be a personal computer (PC), tablet PC, PDA, cellular phone, network device, server, network router, switch or bridge, or any machine capable of executing a set of instructions (continuously or otherwise) specifying actions to be taken by the machine. Furthermore, although only a single machine is shown, the term "machine" should also be considered to include any collection of multiple machines that independently or jointly execute a set of instructions (or multiple sets of instructions) to perform any or more methods discussed herein. Some or all of the components of the computer system 700 may be utilized by or describe any electronic component described herein (e.g., any electronic component that is utilized by the operation of the processing device 230 or the combined chamber 101 or the flow regulator 210).

[0062] An exemplary computer system 700 includes a processing device (processor) 702, a main memory 704 (e.g., ROM, flash memory, dynamic random access memory (DRAM, such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM)), a static memory 706 (e.g., flash memory, static random access memory (SRAM)), and a data storage device 720, which communicate with each other via a bus 710.

[0063] Processor 702 represents one or more general-purpose processing devices, such as a microprocessor, a central processing unit, or the like. More specifically, processor 702 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, or a processor implementing other instruction sets or combinations of instruction sets. Processor 702 may also be one or more special-purpose processing devices, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), a network processor, or the like. Processor 702 is configured to execute instructions 740 for performing the operations discussed herein.

[0064] The computer system 700 may further include a network interface device 708. The computer system 700 may also include a video display unit 712 (e.g., a liquid crystal display (LCD), a cathode ray tube (CRT), or a touch screen), an alphanumeric input device 714 (e.g., a keyboard), a cursor control device 716 (e.g., a mouse), and a signal generation device 722 (e.g., a speaker).

[0065] Power device 718 can monitor the power level of the battery used to power computer system 700 or one or more of its components. Power device 718 may provide one or more interfaces for providing indications of: power level, remaining time window before shutting down computer system 700 or one or more of its components, power consumption rate, whether the computer system is using external power or battery power, and other power-related information. In some implementations, the indications regarding power device 718 may be remote (e.g., accessed via a network connection to a remote backup management module). In some implementations, the battery used by power device 718 may be an uninterruptible power supply (UPS) at the local or remote end of computer system 700. In this implementation, power device 718 may provide information regarding the power level of the UPS.

[0066] Data storage device 720 may include computer-readable storage medium 724 (e.g., a non-transitory computer-readable storage medium) storing one or more sets of instructions 740 (e.g., software) embodying any one or more methods or functions described herein. These instructions 740 may also reside wholly or at least partially within main memory 704 and / or processor 702, which also constitute the computer-readable storage medium, during their execution. The instructions 740 may further be transmitted or received over network 730 (e.g., network 14) via network interface device 708. Although computer-readable storage medium 724 is illustrated as a single medium in the exemplary implementation, it will be understood that computer-readable storage medium 724 may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) storing one or more sets of instructions 740.

[0067] Several details have been set forth in the foregoing description. However, it will be apparent to those skilled in the art who will benefit from this disclosure that embodiments of this disclosure can be practiced without these specific details. Although specific embodiments have been described herein, it should be understood that these embodiments are presented by way of example only and are not intended to be limiting. The breadth and scope of this application should not be limited to any of the embodiments described herein, but should be defined solely by the appended and subsequently filed claims and their equivalents. In fact, various other implementations and modifications of this disclosure besides those described herein will be apparent to those skilled in the art from the foregoing description and drawings. Therefore, such other implementations and modifications are intended to fall within the scope of this disclosure.

[0068] Referring to the accompanying drawings, which form part of the description, and in which specific embodiments are illustrated by way of illustration. While these disclosed embodiments are described in sufficient detail to enable those skilled in the art to practice them, it will be understood that these examples are not limiting, allowing other embodiments to be used and modifications to be made to the disclosed embodiments without departing from their spirit and scope. For example, the blocks of the methods illustrated and described herein need not be performed in the order indicated in some other embodiments. Furthermore, in some other embodiments, the disclosed methods may include more or fewer blocks than described. As another example, some blocks described herein as separate blocks may be combined in some other embodiments. Conversely, in some other embodiments, the content of a single block may be implemented in multiple blocks. Moreover, unless otherwise indicated, the conjunction “or” is intended to have an inclusive meaning herein; that is, the phrase “A, B, or C” is intended to include the possibilities of “A,” “B,” “C,” “A and B,” “B and C,” “A and C,” and “A, B, and C.”

[0069] The terms “example” or “exemplary” are used herein to mean as an example, instance, or illustration. Any aspect or design described herein as an “example” or “exemplary” is not to be construed as superior or advantageous over other aspects or designs. Rather, the use of the terms “example” or “exemplary” is intended to present concepts in a specific manner, and when the terms “about” or “approximately” are used herein, it is intended to mean that the nominal values ​​presented are exactly within ±10%.

[0070] Furthermore, the article “a” (“a” and “an”) used herein and in the appended claims should generally be interpreted as meaning “one or more” unless otherwise stated or clearly indicated in the context as a singular form. References to “an embodiment,” “one embodiment,” “some embodiments,” or “certain embodiments” throughout this specification indicate that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, the phrases “an embodiment,” “one embodiment,” “some embodiments,” or “certain embodiments” appearing in various places throughout this specification do not necessarily refer to the same embodiment.

[0071] Some parts of the detailed description can be presented in terms of algorithms and symbolic representations of operations on data bits within computer memory. These algorithms and representations are the methods used by those skilled in the art of data processing to most effectively communicate the essence of their work to others skilled in the art. Algorithms are, and are generally considered herein, a self-consistent sequence of steps that leads to the desired result. These steps are those that require physical manipulation of physical quantities. This is usually, though not always, in the form of electrical or magnetic signals that can be stored, transmitted, combined, compared, or otherwise manipulated. It has proven convenient, primarily for general reasons, to refer to these signals as bits, values, elements, symbols, characters, items, numbers, or the like.

[0072] However, it should be remembered that all these and similar terms will be associated with appropriate physical quantities and will only be used for convenient labeling of those quantities. Unless otherwise specifically stated, it will be understood from the following discussion that throughout the description, the use of terms such as “receive,” “retrieve,” “send,” “calculate,” “generate,” “process,” “reprocess,” “add,” “subtract,” “multiply,” “divide,” “optimize,” “calibrate,” “detect,” “execute,” “analyze,” “determine,” “enable,” “identify,” “modify,” “transform,” “apply,” “cause,” “store,” “compare,” or similar terms refers to the manipulation and transformation of data representing physical (electronic) quantities in the registers and memories of a computer system into other data representing physical quantities similarly represented in the memory or registers or other such information storage, transmission, or display devices of a computer system.

[0073] Furthermore, although this disclosure has been described herein in the context of a particular implementation in a particular setting for a particular purpose, those skilled in the art will recognize that its use is not limited thereto and that this disclosure can be beneficially implemented for any number of purposes and in any number of settings. Therefore, the claims set forth herein should be interpreted in accordance with the full breadth and spirit of this disclosure as described herein, together with the full scope of equivalents granted under such claims.

Claims

1. A mass flow control device, comprising: A flow control valve, the flow control valve being configured to regulate the gas flow in a gas flow channel; A sensor device configured to generate a signal in response to the state of the gas flow, wherein the transient response of the sensor device is 1 millisecond or less; and A processing device operatively coupled to the flow control valve and the sensor device, the processing device being configured to control the flow control valve based on signals received from the sensor device.

2. The mass flow control device according to claim 1, wherein the sensor device comprises a MEMS device.

3. The mass flow control device according to claim 2, wherein the MEMS device comprises a stand-alone sensing element.

4. The mass flow control device according to claim 3, wherein the freestanding sensing element is directly disposed in the flow path defined by the gas flow channel.

5. The mass flow control device according to claim 1, wherein the signal generated by the sensor device indicates one or more of the gas flow rate or the gas temperature.

6. The mass flow control device according to claim 1, wherein the flow regulating valve comprises a piezoelectric valve, a solenoid valve, or an electric valve, and wherein the sensor device is disposed downstream of the flow regulating valve in the gas flow channel.

7. The mass flow control device according to claim 1, wherein the mass flow control device is integrated into a flow ratio controller or a pulse mass flow system.

8. A system comprising: Processing chamber; A gas flow channel is arranged to deliver gas from a gas source to the processing chamber; A flow control valve, the flow control valve being configured to regulate the gas flow in the gas flow passage; Multiple MEMS devices are located downstream of the flow control valve and arranged in series along the gas flow channel, each of which is configured to generate a signal in response to the state of the gas flow; and A processing device operatively coupled to the flow control valve and each of the plurality of MEMS devices, the processing device being configured to control the flow control valve based on signals received from each of the plurality of MEMS devices.

9. The system of claim 8, wherein at least one of the plurality of MEMS devices is located downstream of the flow regulating valve and is disposed near the inlet of the processing chamber.

10. The system of claim 8, wherein at least one of the plurality of MEMS devices is located downstream of the flow regulating valve and disposed near the reaction site within the processing chamber.

11. The system of claim 8, wherein the processing device is configured to receive a gas flow signal from each of the plurality of MEMS devices and calculate a gas flow rate that resolves the drift of one or more of the plurality of MEMS devices.

12. The system of claim 8, wherein the flow regulating valve includes a flow ratio controller that regulates gas flow through a plurality of gas flow channels including the gas flow channel, wherein the plurality of MEMS devices are each distributed in the plurality of gas flow channels.

13. The system of claim 8, wherein the plurality of MEMS devices are configured to generate a signal indicating one or more of the gas flow rate or gas temperature.

14. A method comprising the following steps: The processing device sends a control signal to the flow regulating valve, which is configured to regulate the mass flow rate in the flow channel; The processing device receives a feedback signal from a MEMS device located downstream of the flow regulating valve. The feedback signal indicates the state of the mass flow rate, wherein the feedback signal generated by the MEMS device indicates one or more of the mass flow rate or the gas temperature, and wherein the adjustment ratio of the mass flow rate is at least 200. The processing device calculates an updated control signal based on the feedback signal from the MEMS device; and The processing device sends the updated control signal to the flow regulating valve.

15. The method of claim 14, wherein the MEMS device comprises a stand-alone sensing element.

16. The method of claim 14, wherein the transient response of the feedback signal generated by the MEMS device is less than 1 millisecond.

17. The method of claim 14, wherein the flow regulating valve comprises a piezoelectric valve, a solenoid valve, or an electric valve.

18. The method of claim 14, further comprising the step of: The processing device generates a pulse control signal based on the feedback signal from the MEMS device; and The control signal of the pulse is sent to the flow regulating valve so that the flow regulating valve generates a mass flow pulse with a pulse width of less than 30 milliseconds.

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