Mass flow controller with high-precision sensor and advanced diagnostic system

Abstract

To provide a mass flow controller having a high accuracy sensor and an advanced diagnosis system.SOLUTION: A mass flow controller which controls the flow rate of a fluid includes a controller, a valve assembly, a pressure sensor, a valve position sensor, and a temperature sensor, and at least one of the sensors is a semiconductor-based sensor. The valve assembly communicates the fluid between an upstream position and a downstream position. The pressure sensor communicates the fluid between an upstream position and a downstream position. The valve assembly can include a piezoelectric valve or a solenoid valve. The controller is communicably linked to the valve assembly and at least one of the sensors. The controller specifies at least one of the pressure, the position, and the temperature. The controller further provides adjustment relative to a valve stroke based on at least one of the actual flow rate of the fluid, the pressure, the position, the temperature, and a predetermined value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 841,110, filed April 30, 2019, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] Equipment used in the manufacture of semiconductor wafers is required to operate with high precision to maintain desired production yields. In the process of producing integrated circuits, semiconductor wafers are treated with several chemicals in a process chamber. Mass flow controllers (MFCs) are used in aligned configurations to deliver these chemicals to the process chamber in a timely and consistent manner and at consistent flow rates. This can be extremely challenging as MFCs must hold very tight accuracy, operate at multiple set points, and be constantly stopped and restarted during the wafer manufacturing process. Precise control of flow rates is required to deliver these chemicals to the process chamber while maintaining the proper mass flow rate with little or no delay. However, current state of the art MFCs and diagnostic systems lack a certain degree of precision, which can affect the manufacturing yield, repeatability, and uniformity of the wafers. Summary of the Invention

[0003] The present disclosure describes an MFC for controlling fluid flow comprising one or more valves and at least one of a semiconductor-based pressure sensor, a position sensor, and a temperature sensor. The pressure sensor can be an absolute pressure (P) sensor and a differential pressure (DP) sensor with various embodiments. The position sensor can be a capacitive sensor, an optical sensor, a strain gauge sensor, a piezoresistive sensor, or a magnetic sensor. In the embodiments described herein, the position sensor(s) and the pressure sensor(s) are used in combination with either an upstream valve or a downstream valve or both to minimize bleed down time and optimize response time. For example, the use of the sensor(s) in combination with the upstream valve allows the valve to operate in the nonlinear region of the laminar flow element (LFE), thereby improving accuracy. The use of the sensor(s) in combination with the downstream valve minimizes bleed down time and optimizes response time.

[0004] For a more complete understanding of the features and advantages of the present disclosure, reference is now made to the detailed description taken in conjunction with the accompanying drawings, in which corresponding numerals in the different figures refer to corresponding parts and in which: [Brief description of the drawings]

[0005] [Figure 1] FIG. 1 is a diagram of an MFC with high-precision sensors and advanced diagnostics system, in accordance with certain example embodiments. [Diagram 2] 1A-1C are diagrams of different configurations of combined pressure transducers, i.e., cells, in which various HP, LP, P and DP circuits are formed, and housing units in which the cell / circuit configurations are assembled, according to certain example embodiments. [Diagram 3] 1A-1C are diagrams of different configurations of combined pressure transducers including various pressure sensing die configurations, in accordance with certain example embodiments. [Figure 4] FIG. 2 is a diagram of a control and diagnostic algorithm, according to certain example embodiments. [Diagram 5] FIG. 2 is a diagram of a computing machine and system application modules in accordance with certain example embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006] Although the making and use of various embodiments of the present disclosure are discussed in detail below, it should be understood that the present disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely exemplary and do not define the scope of the present disclosure. For purposes of clarity, the present disclosure may not describe all features of an actual implementation. Of course, in developing any such actual embodiment, many implementation-specific judgments must be made to achieve the developer's specific goals, including compliance with system-related and business-related constraints that vary from implementation to implementation. Moreover, it will be appreciated that such a development effort may be complex and time-consuming, but would be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

[0007] The function of the downstream solenoid / piezo valve, also called the proportional control valve, is to minimize pressure bleed down time in the supply line when the supply line is shut down. Minimizing or eliminating gas flow into the volume after the proportional control valve in the control line after an outage is important to minimize first-wafer effects or any other performance issues caused by the MFC. Minimizing or eliminating bleed down effects allows the MFC to operate consistently, thereby improving process yields, which can be especially important when used to maintain consistent fluid flow rates among an array of MFCs used to supply chemicals to semiconductor manufacturing chambers.

[0008] As used herein, upstream or upstream side refers to the location or side closest to the fluid source, e.g., after the upstream valve or before the downstream valve in the MFC. As used herein, MFC high pressure (HP) or HP side refers to the upstream or upstream side. As used herein, downstream or downstream side refers to the location or side furthest from the fluid source. As used herein, low pressure (LP) or LP side refers to the downstream or downstream side. As used herein, pressure predetermined value refers to an a priori variable including a flow value based on test data and a laminar flow element (LFE). As used herein, position predetermined value refers to an a priori variable including a valve seat position value based on variables including a valve seat position value and a fluid flow rate. As used herein, valve seat opening refers to the instantaneous position of the valve in either the closed or open state of the valve, or any position between the closed and open states. As used herein, a cell is a collection of one or more sensors in a common package designed to perform a function, i.e., sensors performing a sensing function. The cell may utilize a miniature semiconductor-based pressure sensor, referred to as a die, as described with reference to Figure 3. As used herein, a volume is a reservoir of known volume used in a flow line as a location to make pressure measurements of a fluid flowing through the flow line.

[0009] In a first use case, the MFC senses the upstream and downstream pressures across the LFE using either piezo or solenoid or a combination of upstream and downstream valves and at least one DP, P or DP+P sensor. The MFC's control unit uses the sensed pressure and the LFE predetermined value, i.e., the characterized LFE, to calculate the flow rate and, if necessary, adjust an operating characteristic, such as the opening of the valve seat, of at least one of the valves. The control unit controls the flow rate by maintaining either the upstream or downstream valve in a biased wide open position and adjusting at least one of the open or closed positions of the other valve to control the flow rate. Additionally, the MFC can be used to operate both valves simultaneously, with one valve fully open and the other only partially open, or both only partially open. For example, when using the downstream valve to control the flow rate out of the MFC, the upstream valve can be operated to control the velocity of gas into the MFC to maintain a constant pressure downstream, i.e., using the valve to act as an electronic regulator. This reduces undesirable flow disturbances out of the MFC when the inlet pressure, i.e., pressure sensitivity, is changing. Due to the sensitivity of the semiconductor-based sensor or sensors, the control unit can reduce or eliminate bleed-off of the regulated valve after it has been shut down, thereby improving the turn-off response time of the MFC and subsequently preparing it for the start of the next process.

[0010] In the second use case, the MFC utilizes a high-precision position sensor. The size of the position sensor is a resolution appropriate for the desired flow rate, for example, a 5 nanometer (nm) or smaller position sensor integrated into the downstream valve. Given the accuracy of the position sensor and the predetermined variables, the valve displacement can be measured and the flow rate can be calculated based on the actual sensor measurement of the valve displacement and the predetermined values, i.e., flow rate = f(opening, pressure and temperature). Additionally, the position sensor can be used to rapidly drive the downstream valve from a closed position to an open position based on either a preprogrammed position (feed-forward control) or a known (user-provided) position, allowing for fast response.

[0011] In a third use case, the MFC enables the RoF or "rate of pressure fall" method of in-situ flow verification or the RoD or "rate of pressure decay" method. During steady flow, the upstream valve can be shut off and the seat position on the downstream valve can be increased to compensate for the pressure drop and maintain a constant flow rate out of the MFC. During this process, the control unit can verify the flow rate using DP and P sensors. The control unit can measure and compare the flow rate out of the MFC via several methods. One method measures the rate of pressure fall over time, or dp / dt, in a known volume(s) to calculate the flow rate out of the MFC. A second method determines the flow rate out of the MFC by comparing the current values ​​of pressure, temperature and valve seat opening for the downstream valve with a priori values ​​at a known flow rate. Once the pressure has dropped sufficiently, the upstream valve is reopened to return to DP+P control.

[0012] In a fourth use case, the MFC utilizes upstream and downstream valves, either piezo or solenoid or a combination thereof, and at least one DP, P or DP+P sensor to sense the upstream and downstream pressures, and a position sensor integrated with or used with the downstream valve to sense the position of the downstream valve. The MFC's control unit utilizes the sensed pressures and the LFE predetermined, i.e., characterized, value to calculate the flow rate. The control unit also utilizes the sensed position to determine the valve seat predetermined value and therefore the corresponding flow rate. The calculated flow rate can be compared to the corresponding flow rate to determine the accuracy of the flow rate.

[0013] In a fifth use case, the accuracy of the MFC is compromised when the MFC operates a downstream valve under unsteady conditions, for example, due to pressure changes in the downstream volume. The pressure changes in the volume are due to changes in mass caused by flow into and out of the MFC and through the LFE. In this case, the RoF / RoD as described in the third use case can be used to compensate for the changing mass.

[0014] The MFC presented herein provides an option that can enable users to create early warning / failure prediction or SPC (Statistical Process Control) analysis algorithms that can ensure wafer-to-wafer uniformity and process repeatability and reproducibility.

[0015] 1, an MFC with high accuracy sensors and advanced diagnostic system is shown according to an example embodiment. The MFC comprises a base platform 10, a tube channel 12 with a volume 14, an LFE 15, a volume 16, a temperature sensor 18, a valve assembly with, in this embodiment, valves 20, 22, a semiconductor based pressure sensor and optionally a temperature sensor integrated into a housing unit 24, a semiconductor based position sensor 26 integrated into the valve assembly, and a control unit 28 communicatively coupled to the valves 20, 22 and the sensor. In one embodiment, an additional temperature sensor 18 can be integrated into the housing 24 along with other sensors to compensate for any temperature induced effects that the operation of the other sensors may have on the actual measurements.

[0016] In practice, the base platform 10 is coupled to an upstream fluid source and to a downstream process chamber through flow lines. The fluid flows through a tube channel 12 where a sensor(s) in a housing unit 24 can sense the pressure and optionally the temperature in the volumes 14 and 16. The temperature sensor 18 can also be used to determine the ambient temperature. Although not shown, the temperature sensor 18 also includes a communication line to a control unit 28. In some specific embodiments, the sensor 24 can include a high pressure (HP) side (upstream) pressure sensor and a low pressure (LP) side pressure sensor. The HP side and the LP side can each include at least one absolute pressure (P) sensor and at least one differential pressure (DP) sensor. In practice, the control unit 28 maintains operational control of the valves 20, 22 based on the desired flow rate, i.e., the set point and the sensor measurements. With respect to the position sensor 26, the control unit 28 can determine the position of the valve 22 as the stem and disc 32 transition to and from the seat 32 during opening and closing of the seat 32. The control unit 28 can use the sensed data to perform diagnostics and control MFC operation.

[0017] Although the embodiments described herein refer to both pressure and position sensors 24 as being semiconductor based, it should be understood that in some embodiments, one of these sensors or only one type of sensor may be semiconductor based. Indeed, it should also be understood that the MFC may be communicatively coupled to other equipment, such as wafer fabrication equipment. Thus, the MFC may not need to be configured to include a pressure sensor or all pressure sensors, for example, because the wafer fabrication equipment may provide pressure measurements for the downstream or upstream side. It should also be understood that the valve assembly may include only valve 20 or valve 22, depending on the application.

[0018] 2, there is shown different ICs, i.e. cells, in which various HP, LP, P and DP circuits are formed, according to example embodiments, and a housing unit 24 in which the cell / circuit configurations are incorporated. The cells 40-46 include at least one P cell and at least one DP cell. In this embodiment, the cells are configured to operate in high and low pressure ranges and in multiple pressure ranges. The housing unit 24 is configured to include an LP P sensor, a temperature sensor, an HP DP sensor and an HP P sensor. However, it is clear that the housing unit 24 can be configured to include any cell configuration. The temperature sensor can be a diode or thermistor, or others known in the art, i.e. a platinum temperature sensor.

[0019] Referring now to FIG. 3, individual cells 50-56 are shown including various die configurations, according to example embodiments. The die are designed to reduce manufacturing costs, reduce size, and improve cell accuracy. The die is the functional circuitry of the cell. Cell 50 is an individual package that houses a single die 50A or 50B. Die 50A includes the DP functional circuitry and die 50B includes the P functional circuitry. In this embodiment, dies 50A and 50B are packaged separately and later joined together by welding or an alternative method. Cell 52 includes dies 52A and 52B, which are both DP functional circuits. The range of each DP functional circuit can be unique so that the cell can operate over a wider range or over different ranges. However, because the DP functional circuits are manufactured and packaged together, manufacturing costs are reduced and the usable range and accuracy of the cell is improved since there is no operational or cell redundancy. In this particular embodiment, die 52C includes the P function circuitry, which is packaged separately from the DP cell and later joined together by welding or an alternative method. Cell 54 includes die 54A, 54B, and 54C. Dies 54A and 54B are the DP function circuitry, and die 54C is the P function circuitry. In this particular configuration, all the dies are manufactured together and therefore packaged together, again reducing manufacturing costs and improving accuracy. Finally, cell 56 includes one die 56A. Die 56A includes one or more DP function cells and one or more P function cells, and an optional temperature measurement cell. The die configurations described above are not exhaustive and other configurations are certainly possible, for example cells with one or more dies having multiple P function circuits.

[0020] 4, a control and diagnostic algorithm according to an example embodiment is shown. The algorithm begins at block 80 where temperature sensor data and at least one of pressure sensor data and position sensor data are processed. The pressure data can include DP (differential pressure) data or P (absolute pressure) data or both. At block 82, the position of the upstream valve is identified based on a priori position data. The a priori position data is based on test data such as operating conditions, flow rate, a particular valve and a particular position sensor. The valve position is compared to the a priori valve seat data and the actual flow rate to identify the accurate valve seat position. The a priori valve seat data is based on test data such as operating conditions, flow rate and valve seat position. At block 84, a pressure is identified based on the a priori data, a flow rate is identified based on the identified pressure and a known volume, and the flow rate is compared to the actual flow rate. The a priori pressure data is a pressure value based on the flow rate and LFE characteristics.

[0021] 5, a computing machine 100 and a system application module 200 are shown according to an example embodiment. The computing machine 100 can correspond to any of a variety of computers, mobile devices, laptop computers, servers, embedded systems, or computing systems presented herein. The module 200 can include one or more hardware or software elements, such as other OS applications and user and kernel space applications, designed to facilitate the computing machine 100 to execute the various methods and processing functions presented herein. The computing machine 100 can include various internal or attached components, such as a processor 110, a system bus 120, a system memory 130, a storage medium 140, an input / output interface 150, a network 170, such as a network interface 160 for communicating with a network, such as Cellular / GPS, Bluetooth, WiFi, or Devicenet, EtherCAT, Analog, RS485, and one or more sensors 180.

[0022] The computing machine may be implemented as a conventional computer system, an embedded controller, a laptop, a server, a mobile device, a smart phone, a wearable computer, a customized machine, any other hardware platform, or any combination or plurality of them. The computing machine may be a distributed system configured to function using multiple computing machines interconnected via a data network or bus system.

[0023] The processor 110 can be designed to execute code instructions to perform the operations and functions described herein, manage request flow and address mapping, perform calculations and generate commands. The processor 110 can be configured to monitor and control the operation of components in the computing machine. The processor 110 can be a general-purpose processor, a processor core, a multiprocessor, a reconfigurable processor, a microcontroller, a digital signal processor ("DSP"), an application specific integrated circuit ("ASIC"), a controller, a state machine, gate logic, a discrete hardware component, any other processing unit, or any combination or plurality thereof. The processor 110 can be a single processing unit, multiple processing units, a single processing core, multiple processing cores, a dedicated processing core, a coprocessor, or any combination thereof. According to some particular embodiments, the processor 110 can be a software-based or hardware-based virtual computing machine executing within one or more other computing machines, along with other components of the computing machine 100.

[0024] The system memory 130 may include non-volatile memory, such as read-only memory ("ROM"), programmable read-only memory ("PROM"), erasable programmable read-only memory ("EPROM"), flash memory, or any other device capable of storing program instructions or data with or without the application of power. The system memory 130 may also include volatile memory, such as random access memory ("RAM"), static random access memory ("SRAM"), dynamic random access memory ("DRAM"), and synchronous dynamic random access memory ("SDRAM"). Other types of RAM may also be used to implement the system memory 130. The system memory 130 may be implemented using a single memory module or multiple memory modules. Although the system memory 130 is shown as being part of the computing machine, those skilled in the art will understand that the system memory 130 may be separate from the computing machine 100 without departing from the scope of the subject technology. It should also be understood that the system memory 130 may include or operate in conjunction with a non-volatile storage device, such as the storage medium 140.

[0025] The storage medium 140 may include a hard disk, a floppy disk, a compact disk read-only memory ("CD-ROM"), a digital versatile disk ("DVD"), a Blu-ray disk, a magnetic tape, a flash memory, other non-volatile memory devices, a solid-state drive ("SSD"), any magnetic storage device, any optical storage device, any electrical storage device, any semiconductor storage device, any physically based storage device, any other data storage device, or any combination or plurality of them. The storage medium 140 may store one or more operating systems, application programs and program modules, data, or any other information. The storage medium 140 may be part of a computing machine or may be connected to a computing machine. The storage medium 140 may also be part of one or more other computing machines in communication with the computing machine, such as a server, a database server, cloud storage, network attached storage, etc.

[0026] The application module 200 and other OS application modules may include one or more hardware or software elements configured to facilitate a computing machine to execute various methods and processing functions presented herein. The application module 200 and other OS application modules may include one or more algorithms or sequences of instructions stored as software or firmware in association with the system memory 130, the storage medium 140, or both. The storage medium 140 may thus represent an example of a machine or computer readable medium that may store instructions or code for execution by the processor 110. A machine or computer readable medium may generally refer to any medium or media used to provide instructions to the processor 110. Such machine or computer readable media associated with the application module 200 and other OS application modules may include computer software products. It should be understood that the computer software products including the application module 200 and other OS application modules may also be associated with one or more processes or methods of delivering the application module 200 and other OS application modules to a computing machine via a network, any signal-carrying medium, or any other communication or delivery technology. Application module 200 and other OS application modules may also include hardware circuitry or information for configuring hardware circuitry, such as microcode, or configuration information for an FPGA or other PLD. In one example embodiment, application module 200 and other OS application modules may include algorithms capable of performing the functional operations described by the flowcharts (operational modes) of the computer system presented herein.

[0027] Input / output ("I / O") interface 150 can be configured to couple to one or more external devices, receive data from one or more external devices, and transmit data to one or more external devices. Such external devices, along with various internal devices, may also be known as peripheral devices. I / O interface 150 can include both electrical and physical connections to couple various peripheral devices to computing machine or processor 110. I / O interface 150 can be configured to communicate data, address, and control signals between the peripheral devices and computing machine or processor 110. I / O interface 150 can be configured to implement any standard interface, such as Small Computer System Interface ("SCSI"), Serial Attached SCSI ("SAS"), Fibre Channel, Peripheral Component Interconnect ("PCI"), PCI Express (PCIe), serial bus, parallel bus, Advanced Technology Attachment ("ATA"), Serial ATA ("SATA"), Universal Serial Bus ("USB"), Thunderbolt, FireWire, various video buses, etc. I / O interface 150 may be configured to implement only one interface or bus technology. Alternatively, I / O interface 150 may be configured to implement multiple interface or bus technologies. I / O interface 150 may be configured to operate as part of, as all of, or in conjunction with system bus 120. I / O interface 150 may include one or more buffers for buffering transmissions between one or more external devices, internal devices, computing machines, or processors 110.

[0028] I / O interface 150 can couple the computing machine to a variety of input devices including a mouse, touch screen, scanner, electronic digitizer, sensor, receiver, touch pad, track ball, camera, microphone, keyboard, any other pointing device, or any combination thereof. I / O interface 120 can couple the computing machine to a variety of output devices including video displays, speakers, printers, projectors, haptic feedback devices, automation controls, robotic components, actuators, motors, fans, solenoids, valves, pumps, transmitters, signalers, lights, etc.

[0029] The computing machine 100 may operate in a networked environment, with logical connections through the NIC 160 to one or more other systems or computing machines over a network. The network may include a wide area network (WAN), a local area network (LAN), an intranet, the Internet, a wireless access network, a wired network, a mobile network, a telephone network, an optical network, or a combination thereof. The network may be a packet-switched network, a circuit-switched network of any topology and may use any communication protocol. The communication links in the network may involve a variety of digital or analog communication media, such as fiber optic cables, free-space optics, wave guides, electrical conductors, wireless links, antennas, radio frequency communications, and the like.

[0030] The one or more sensors 180 can be position and pressure sensors. The pressure sensor can be an absolute pressure (P) sensor or a differential pressure (DP) sensor. The position sensor can be a capacitive sensor, an optical sensor, a strain gauge sensor, or a magnetic sensor. The sensor 180 can be a conventional sensor or a semiconductor-based sensor.

[0031] The processor 110 may be connected to other elements of a computing machine or to various peripherals discussed herein via a system bus 120. It should be understood that the system bus 120 may be internal to the processor 110, external to the processor 110, or both. According to some embodiments, the processor 110, other elements of the computing machine, or any of the various peripherals discussed herein may be incorporated into a single device, such as a system on a chip ("SOC"), system on a package ("SOP"), or ASIC device.

[0032] The embodiments may include a computer program that embodies the functions described and illustrated herein, the computer program being implemented in a computer system that includes instructions stored in a machine-readable medium and a processor that executes the instructions. However, it should be apparent that there may be many different ways of implementing the embodiments in computer programming, and the embodiments should not be construed as being limited to any one set of computer program instructions unless otherwise disclosed in the exemplary embodiments. Furthermore, a skilled programmer would be able to write such a computer program to implement one of the disclosed embodiments based on the accompanying flow charts, algorithms, and related descriptions in the body of the application. Thus, disclosure of a particular set of program code instructions is not deemed necessary to fully understand how to make and use the embodiments. Furthermore, one skilled in the art would understand that one or more aspects of the embodiments described herein may be performed by hardware, software, or a combination thereof, such that they may be embodied in one or more computing systems. Furthermore, any reference to an act performed by a computer should not be construed as being performed by a single computer, since two or more computers may perform the act.

[0033] The example embodiments described herein can be used with computer hardware and software to perform the methods and processing functions described above. The systems, methods and procedures described herein can be embodied in a programmable computer, computer executable software, or digital circuitry. The software can be stored on a computer readable medium. For example, computer readable media can include floppy disks, RAM, ROM, hard disks, removable media, flash memory, memory sticks, optical media, magneto-optical media, CD-ROMs, etc. Digital circuitry can include integrated circuits, gate arrays, building block logic, field programmable gate arrays (FPGAs), etc.

[0034] The example systems, methods, and acts described in the embodiments presented above are exemplary, and in alternative embodiments, some specific acts may be performed in a different order, in parallel with one another, omitted entirely, and / or combined between different example embodiments, and / or some specific additional acts may be performed, without departing from the scope and spirit of the various embodiments. Accordingly, such alternative embodiments are included in the description herein.

[0035] As used herein, the singular forms "a", "an" and "the" are intended to include the plural, unless the context clearly indicates otherwise. It will be further understood that the terms "comprise" and / or "comprising" as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y." As used herein, phrases such as "from about X to Y" mean "from about X to about Y."

[0036] As used herein, "hardware" may include a combination of discrete components, an integrated circuit, an application specific integrated circuit, a field programmable gate array, or other suitable hardware. As used herein, "software" may include one or more objects, agents, threads, lines of code, subroutines, separate software applications, two or more lines of code or other suitable software structures operating in one or more processors (wherein the processor may include one or more microcomputers or other suitable data processing units, memory devices, input / output devices, displays, data input devices such as keyboards or mice, peripherals such as printers and speakers, associated drivers, control cards, power supplies, network devices, docking station devices, or other suitable devices operating under the control of a software system with a processor or other devices), two or more lines of code or other suitable software structures operating in two or more software applications, or other suitable software structures. In one exemplary embodiment, the software may include one or more lines of code or other suitable software structures operating in a general-purpose software application, such as an operating system, and one or more lines of code or other suitable software structures operating in a dedicated software application. As used herein, "couple" and cognate terms such as "couples" and "coupled" may include a physical connection (such as through copper conductors), a virtual connection (such as through randomly assigned memory locations in a data memory device), a logical connection (such as through logic gates in a semiconductor device), any other suitable connection, or a suitable combination of such connections.The term "data" may refer to any suitable structure for using, transporting, or storing data, such as a data field, a data buffer, a data message having a data value and sender / recipient address data, a control message having a data value and one or more operators that cause a receiving system or component to perform some function with the data, or other suitable hardware or software component for the electronic processing of data.

[0037] Generally, a software system is a system that runs on a processor to perform a given function in response to a given data field. For example, a system can be defined by the function that the system performs and the data field on which the system performs the function. As used herein, a NAME system (where NAME is typically the name of the generic function performed by the system) refers to a software system that runs on a processor and is configured to perform a disclosed function on a disclosed data field. Unless a specific algorithm is disclosed, any suitable algorithm known to one of ordinary skill in the art to perform a function with the associated data field is contemplated as being within the scope of this disclosure. For example, a message system that generates a message including a sender address field, a recipient address field, and a message field includes software operating on a processor that can obtain the sender address field, the recipient address field, and the message field from a suitable system or device of the processor, such as a buffer device or system, assemble the sender address field, the recipient address field, and the message field into a suitable electronic message format (such as an email message, a TCP / IP message, or any other suitable message format having sender address fields, recipient address fields, and message fields), and transmit the electronic message using the electronic messaging system and device of the processor over a communication medium, such as a network. One of ordinary skill in the art will be able to provide specific encoding for a particular application based on the above disclosure, which is intended to illustrate exemplary embodiments of the present disclosure, but is not intended to provide guidance to persons other than those skilled in the art, such as persons unfamiliar with programming in a suitable programming language or with processors.Specific algorithms for performing certain functions may be provided in flowchart form or other suitable format, and data fields and associated functions may be shown in an exemplary sequence of operations, which sequence may be rearranged as suitable and is not intended as limiting unless expressly stated to be limiting.

[0038] As used herein, the singular forms "a", "an" and "the" are intended to include the plural, unless the context clearly indicates otherwise. It will be further understood that the terms "comprise" and / or "comprising" as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as "between X and Y" and "between about X and Y" should be interpreted to include X and Y. As used herein, phrases such as "between about X and Y" mean "between about X and about Y." As used herein, phrases such as "from about X to Y" mean "from about X to about Y."

[0039] The above disclosed embodiments are presented for the purpose of illustration and to enable those skilled in the art to practice the present disclosure, but the present disclosure is not intended to be exhaustive or limited to the disclosed forms. Many insubstantial modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the present disclosure. The claims are intended to broadly encompass the disclosed embodiments and any such modifications. Furthermore, the following clauses represent further embodiments of the present disclosure and should be considered to be within the scope of the present disclosure.

[0040] Clause 1. A mass flow controller for controlling a fluid flow comprising: a valve assembly in fluid communication with at least one upstream location and at least one downstream location; at least one semiconductor based pressure sensor in fluid communication with the at least one upstream location and the at least one downstream location; and a controller communicatively coupled to the valve assembly and the at least one pressure sensor, the controller determining a pressure for the at least one upstream location and the at least one downstream location and effecting an adjustment to a valve stroke of at least one valve in fluid communication with at least one of the upstream location and the downstream location based on an actual fluid flow rate, the pressure and a predetermined value.

[0041] Clause 2. The mass flow controller of clause 1, wherein the at least one valve is either a piezoelectric valve or a solenoid valve, and the pressure sensor is at least one of an absolute pressure sensor and a differential pressure sensor.

[0042] Clause 3. The mass flow controller of clause 1, further comprising a position sensor communicatively coupled to the at least one valve.

[0043] Clause 4. The mass flow controller of clause 3, wherein the position sensor is one of a semiconductor-based position sensor, a capacitance-based position sensor, a resistance-based position sensor, a piezo-resistance-based position sensor and a capacitance-based position sensor.

[0044] Clause 5. The mass flow controller of clause 3, wherein the controller determines a position of the at least one valve and effects an adjustment to a valve stroke of the at least one valve based on the actual fluid flow rate and at least the pressure, position and another predetermined value.

[0045] Clause 6. The mass flow controller of clause 3, wherein the controller determines a position of at least one valve and effects an adjustment to the position of the at least one valve based on a stop signal, the actual fluid flow rate and at least the position, the pressure and the predetermined value and the further predetermined value.

[0046] Clause 7. The mass flow controller of clause 1, wherein the predetermined value is based on a priori pressure information and the further predetermined value is based on a priori position information.

[0047] Clause 8. The mass flow controller of clause 1, further comprising a position sensor and a temperature sensor, the position sensor communicatively coupled to the at least one valve.

[0048] Clause 9. The mass flow controller of clause 8, wherein at least one of the position sensor and the temperature sensor is a semiconductor-based sensor.

[0049] Clause 10. The mass flow controller of clause 8, wherein the controller determines a position of the at least one valve, determines a temperature, and effects an adjustment to a valve stroke of the at least one valve based on the actual fluid flow rate and at least the pressure, position, temperature, and the given valve.

[0050] Clause 11. A method of controlling a fluid flow rate using a mass flow controller, comprising: controlling a fluid flow rate between at least one upstream location and at least one downstream location; sensing pressure at the at least one upstream location and the at least one downstream location using at least one semiconductor based pressure sensor; determining pressure at the at least one upstream location and the at least one downstream location; and adjusting the flow rate by effecting an adjustment of a valve stroke of at least one valve in fluid communication with at least one of the upstream location and the at least one downstream location based on an actual fluid flow rate, the pressure and a predetermined value.

[0051] Clause 12. The method of clause 11, further comprising: sensing a position of the at least one valve from a position sensor communicatively coupled to the at least one valve; determining a position of the at least one valve; and adjusting the flow rate by effecting an adjustment to a valve stroke of at least one valve in fluid communication with at least one of the upstream location and the at least one downstream location based on the actual fluid flow rate and at least the pressure, position and another predetermined value.

[0052] Clause 13. The method of clause 12, wherein the position sensor is one of a semiconductor-based position sensor, a capacitance-based position sensor, a resistance-based position sensor, and a capacitance-based position sensor.

[0053] Clause 14. The method of clause 11, further comprising: sensing a position of the at least one valve using a position sensor communicatively coupled to the at least one valve; sensing a temperature within the valve assembly using a temperature sensor; determining a position of at least one valve; determining a temperature; determining a fluid flow rate; and causing an adjustment to a valve stroke of at least one valve in fluid communication with at least one of the upstream location and the at least one downstream location based on the actual fluid flow rate and at least the pressure, position, temperature, the predetermined valve, and the another predetermined value.

[0054] Clause 15. The method of clause 14, wherein at least one of the position sensor and the temperature sensor is a semiconductor-based position sensor.

[0055] Clause 16. The method of clause 11, wherein the predetermined value is a fluid flow rate based at least in part on a characteristic of a laminar flow element.

[0056] Clause 17. The method of clause 11, wherein the predetermined value is based on a priori pressure information and the further predetermined value is based on a priori position information.

[0057] Clause 18. A mass flow controller for controlling a fluid flow comprising: a valve assembly in fluid communication with at least one upstream location and at least one downstream location; at least one semiconductor based position sensor communicatively coupled to at least one valve of the valve assembly; and a controller communicatively coupled to the valve assembly and the at least one position sensor, the controller determining a position for at least one valve and effecting an adjustment to a valve stroke of at least one valve in fluid communication with at least one of the upstream location and the downstream location based on an actual fluid flow rate, a pressure measurement associated with at least one of the upstream location and the downstream location, the position, and a predetermined value.

[0058] Clause 19. The mass flow controller of clause 18, wherein the predetermined value is based on a priori position information.

[0059] Clause 20. The mass flow controller of clause 18, further comprising a semiconductor based temperature sensor, wherein the controller determines a position of the at least one valve, determines a temperature, and effects an adjustment to a valve stroke of the at least one valve based on the actual fluid flow rate and at least the pressure, position, temperature, and the predetermined value. The inventions disclosed herein include the following: [Aspect 1] A mass flow controller for controlling a fluid flow rate, comprising: a valve assembly in fluid communication with at least one upstream location and at least one downstream location in a same flow path as the upstream location, the at least one valve having a valve stem and a valve seat; at least one semiconductor-based pressure sensor in fluid communication with the at least one upstream location and the at least one downstream location; a position sensor communicatively coupled to the at least one valve; a controller communicatively coupled to the valve assembly and the at least one pressure sensor, determining pressures for the upstream and downstream locations; controlling the valve assembly to adjust a valve stroke of at least one valve in fluid communication with the upstream location and the downstream location based on an actual fluid flow rate and a desired positive fluid flow rate; receiving a value from the position sensor representing a measurement of an actual position of the valve stem as it moves from the valve seat in accordance with the adjustment; performing diagnostics on the mass flow controller by comparing an actual position of the valve stem to a predetermined position of the valve stem, the predetermined position being determined from a predetermined relationship between pressures at the upstream and downstream locations and a position of the valve stem, and from a predetermined relationship between the desired positive fluid flow rate and the valve stroke; A controller; A mass flow controller comprising: [Aspect 2] the at least one valve is either a piezoelectric valve or a solenoid valve; 2. The mass flow controller of claim 1, wherein the pressure sensor is at least one of an absolute pressure sensor and a differential pressure sensor. [Aspect 3] 2. The mass flow controller of claim 1, wherein the at least one semiconductor-based pressure sensor comprises an absolute pressure sensor and a differential pressure sensor, both of the absolute pressure sensor and the differential pressure sensor integrated into a single cell. [Aspect 4] 2. The mass flow controller of claim 1, wherein the position sensor is one of a semiconductor-based position sensor, a capacitance-based position sensor, a resistance-based position sensor, a piezo-resistance-based position sensor, and a capacitance-based position sensor. [Aspect 5] The controller: Identifying another measurement of the position of at least one valve; 4. The mass flow controller of claim 3, further comprising: providing an adjustment to a valve stroke of the at least one valve based on the actual fluid flow rate and at least the other measured value and another predetermined value. [Aspect 6] The controller: identifying the position of at least one valve; 4. The mass flow controller of claim 3, further comprising: a stop signal; providing an adjustment to the position of the at least one valve based on the actual fluid flow rate and at least the measured value and the predetermined value and another predetermined value. [Aspect 7] 2. The mass flow controller of embodiment 1, further comprising a position sensor and a temperature sensor, the position sensor integrated into the at least one valve. [Aspect 8] 8. The mass flow controller of claim 7, wherein at least one of the position sensor and the temperature sensor is a semiconductor-based sensor. [Aspect 9] The controller: determining a position of the at least one valve; Identify the temperature, 8. The mass flow controller of claim 7, further comprising: providing an adjustment to a valve stroke of at least one valve based on the actual fluid flow rate and at least the position, temperature, and the predetermined value. [Aspect 10] 1. A method for controlling a fluid flow rate using a mass flow controller, comprising: Controlling a fluid flow rate between at least one upstream location and at least one downstream location in the same flow path as the upstream location; sensing pressure at the at least one upstream location and at least one downstream location with at least one semiconductor based pressure sensor; determining a pressure at the at least one upstream location and at least one downstream location; adjusting the flow rate by effecting an adjustment of a valve stroke of at least one valve in fluid communication with the upstream location and the downstream location based on an actual fluid flow rate, a pressure at the at least one upstream location and the at least one downstream location, and a predetermined valve position based on a priori pressure information, the at least one valve having a valve stem and a valve seat; receiving measurement data from the position sensor to identify a position of the valve stem as it transitions from the valve seat; performing diagnostics on the mass flow controller by comparing actual measurements of valve travel to a predetermined value of calculated valve travel based on a priori position information and a priori pressure information; A method comprising: [Aspect 11] The method of embodiment 10, wherein receiving data from at least one semiconductor-based pressure sensor includes receiving data from an absolute pressure sensor and a differential pressure sensor, both of the absolute pressure sensor and the differential pressure sensor being incorporated into a single cell. [Aspect 12] 12. The method of claim 11, wherein the position sensor is one of a semiconductor-based position sensor, a capacitance-based position sensor, a resistance-based position sensor, and a capacitance-based position sensor. [Aspect 13] sensing a position of the at least one valve using a position sensor associated with the at least one valve while the at least one valve moves from its seat; Sensing a temperature within the valve assembly with a temperature sensor; determining a position of the at least one valve; and Determining the temperature; Determining a fluid flow rate; providing an adjustment to a valve stroke of the at least one valve in fluid communication with the upstream location and the downstream location based on an actual fluid flow rate, a temperature, and a predetermined value; 11. The method of embodiment 10, further comprising: [Aspect 14] 14. The method of claim 13, wherein at least one of the position sensor and the temperature sensor is a semiconductor-based position sensor. [Aspect 15] 11. The method of embodiment 10, wherein the predetermined value is a fluid flow rate based at least in part on a characteristic of a laminar flow element and a value position provided by a signal from the position sensor. [Aspect 16] A mass flow controller for controlling a fluid flow rate, comprising: a valve assembly in fluid communication with at least one upstream location and at least one downstream location in a same flow path as the upstream location, the at least one valve having a valve stem and a valve seat; at least one semiconductor based position sensor communicatively coupled to at least one valve of the valve assembly; a controller communicatively coupled to the valve assembly and the at least one position sensor, determining a valve stem position for at least one valve in response to measurement data received from the position sensor, the valve stem position being used to perform diagnostics on the mass flow controller by comparing an actual position of valve travel during movement of the valve stem from the valve seat to a predetermined value of calculated valve travel, the predetermined value of calculated valve travel being determined from a predetermined relationship between pressures at the upstream and downstream locations and the valve stem position and from a predetermined relationship between the desired positive fluid flow rate and the valve stroke; providing an adjustment to a valve stroke of at least one valve in fluid communication with at least one of the upstream location and the downstream location based on an actual fluid flow rate, pressure measurements associated with the at least one upstream location and the at least one downstream location, the position of the valve stem, and the predetermined value. A controller; A mass flow controller for controlling a fluid flow rate. [Aspect 17] 17. The mass flow controller of claim 16, wherein the predetermined value is based on a priori position information. [Aspect 18] Semiconductor-based temperature sensors, Further comprising: The controller: Identifying the position of at least one valve; Identify the temperature, providing an adjustment to a valve stroke of the at least one valve based on the actual fluid flow rate and at least the pressure measurements, position, temperature, and the selected valve. 17. A mass flow controller according to embodiment 16. [Explanation of symbols]

[0060] 10 Base Platform 12 tube channels 14 Volume 15 LFE 16 Volume 18 Temperature Sensor 20 Valve 22 Valve 24 Housing Units 26 Position Sensor 28 Control Unit

Claims

1. a valve assembly in fluid communication with at least one upstream location and at least one downstream location; at least one semiconductor-based pressure sensor in fluid communication with the at least one upstream location and the at least one downstream location; a position sensor communicatively coupled to at least one valve of the valve assembly; a controller communicatively coupled to the valve assembly, the at least one semiconductor based pressure sensor, and the position sensor, determining a pressure for the at least one upstream location and the at least one downstream location; determining a position of the at least one valve based on a priori position information; determining an actual position of the at least one valve by comparing the position of the at least one valve to the a priori position information and an actual fluid flow rate; effecting an adjustment to a valve stroke of the at least one valve based on the pressure, the actual position, and a comparison of the actual fluid flow rate to a flow rate determined based on a priori pressure information and a known volume. A controller; A mass flow controller for controlling a fluid flow rate.

2. the at least one valve being either a piezoelectric valve or a solenoid valve; 2. The mass flow controller of claim 1, wherein the pressure sensor is at least one of an absolute pressure sensor and a differential pressure sensor.

3. 2. The mass flow controller of claim 1, wherein the position sensor is one of a semiconductor-based position sensor, a capacitance-based position sensor, a resistance-based position sensor, and a piezo-resistance-based position sensor.

4. The controller:

2. The mass flow controller of claim 1, wherein the at least one valve is adapted to provide an adjustment to the actual position of the at least one valve based on a stop signal, the actual position, the pressure, and a comparison of the actual fluid flow rate to a flow rate determined based on a priori pressure information and a known volume.

5. The mass flow controller of claim 1 further comprising a temperature sensor.

6. 6. The mass flow controller of claim 5, wherein the temperature sensor is a semiconductor-based sensor.

7. The controller: Identify the temperature, 6. The mass flow controller of claim 5, wherein the at least one valve is adapted to provide an adjustment to a valve stroke of the at least one valve based on the pressure, the actual position, the temperature, and a comparison of the actual fluid flow rate to an determined flow rate based on a known volume and a pressure determined based on a priori pressure information.

8. Controlling a fluid flow rate between at least one upstream location and at least one downstream location; sensing pressure at the at least one upstream location and at least one downstream location with at least one semiconductor based pressure sensor; determining a pressure at the at least one upstream location and at least one downstream location; sensing a position of the at least one valve from a position sensor communicatively coupled to at least one valve of a valve assembly in fluid communication with the at least one upstream location and the at least one downstream location; determining a position of the one valve based on a priori position information; determining an actual position of the at least one valve by comparing the position of the at least one valve to the a priori position information and an actual fluid flow rate; adjusting the fluid flow rate by effecting an adjustment of a valve stroke of the at least one valve based on the pressure, the actual position, and a comparison of the actual fluid flow rate to a flow rate determined based on a pressure determined based on a priori pressure information and a known volume; 23. A method for controlling a fluid flow rate using a mass flow controller, comprising:

9. The method of claim 8 , wherein the position sensor is one of a semiconductor-based position sensor, a capacitance-based position sensor, a resistive-based position sensor, and a capacitance-based position sensor.

10. Sensing a temperature within the valve assembly with a temperature sensor; Determining the temperature; Determining a fluid flow rate; effecting an adjustment to a valve stroke of the at least one valve based on the pressure, the actual position, the temperature, and a comparison of the actual fluid flow rate to a flow rate determined based on a known volume and a pressure determined based on a priori pressure information; The method of claim 8 further comprising:

11. The method of claim 10 , wherein the temperature sensor is a semiconductor-based position sensor.

12. a valve assembly in fluid communication with at least one upstream location and at least one downstream location; at least one semiconductor based position sensor communicatively coupled to at least one valve of the valve assembly; a controller communicatively coupled to the valve assembly and the at least one semiconductor based position sensor, determining a position of the at least one valve based on a priori position information; determining an actual position of the at least one valve by comparing the position of the at least one valve to the a priori position information and an actual fluid flow rate; effecting an adjustment to a valve stroke of the at least one valve based on the actual position and a comparison of the actual fluid flow rate to a flow rate determined based on a priori pressure information and a known volume. A controller; A mass flow controller for controlling a fluid flow rate.

13. Semiconductor-based temperature sensors, Further comprising: The controller: Identify the temperature, effecting an adjustment to a valve stroke of the at least one valve based on the actual position, the temperature, and a comparison of the actual fluid flow rate to a flow rate determined based on a known volume and a pressure determined based on a priori pressure information.

13. The mass flow controller according to claim 12.

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