Micro-electromechanical device for use in a flow control apparatus

Abstract

This document discloses embodiments of a sensor device, a system incorporating the sensor device, and a method of manufacturing the sensor device. In one embodiment, the sensor device includes a freestanding sensing element, such as a microelectromechanical system (MEMS) device. The sensor device further includes a metal strip to facilitate mounting the MEMS device to a mounting plate. The sensor device further includes a conformal coating on at least a portion of the sensing region of the sensor device.

Description

[Technical Field]

[0001] The embodiments of this case generally relate to methods and apparatus for monitoring and controlling the flow rate of gases. [Previous Technology]

[0002] Controlling gas flow rates presents 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 to clean manufacturing equipment and / or chambers used in the manufacture of 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). Conventional 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.) may be subject to one or more limitations depending on the application in which the MFC is used. For example, thermal MFCs utilize thermal sensors to measure flow and control needle valves to modulate the 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 with precise gas control and timing requirements. [Summary of the Invention]

[0004] Certain embodiments of this application relate to a sensor device, a system integrating a sensor device, and a method for adapting a sensor device for use in a flow control device. In one embodiment, a sensor device includes an elongated support structure, electrodes, and a freestanding sensing element. The elongated support structure includes an interface region, a sensor region, and a coupling region located between the interface region and the sensor region. Electrodes are disposed on the interface region, and a freestanding sensing element is suspended at the sensor region and electrically coupled to the electrodes. In some embodiments, the sensor device includes a metal strip surrounding the coupling region. In some embodiments, the sensor device includes a non-conductive conformal coating on at least a portion of the sensor region. In some embodiments, the sensor device includes a micro-electromechanical system (MEMS) device.

[0005] In another embodiment of this invention, a flow control device includes a gas flow channel defining a gas flow path, a flow modulation valve configured to modulate gas flow in the gas flow channel, a sensor device including a stand-alone sensing element, and a processing device. In some embodiments, the stand-alone sensing element is disposed within the gas flow path. In some embodiments, the processing device is operatively coupled to the flow modulation valve and the sensor device, and is configured to control the flow modulation valve based on signals received from the flow sensor device. In some embodiments, the sensor device includes a microelectromechanical system (MEMS) device.

[0006] In another embodiment of this invention, a method for adapting a flow sensor device to a gas flow channel includes providing a sensor device, depositing a conformal coating on the sensor device to at least partially cover a sensor region of the sensor device, and depositing a metal strip on the sensor device to surround a coupling region of the sensor device. In some embodiments, the sensor device includes an elongated support structure comprising an interface region, a sensor region, and a coupling region located between the interface region and the sensor region.

Implementation Method

[0024] The embodiments described herein relate to a sensor device adapted for use in a mass flow control device, a system incorporating the sensor device, and a method for adapting the sensor device for such use. In some embodiments, the sensor device includes a MEMS device having a stand-alone sensor element that is directly disposed in the flow path of a gas flow channel. The MEMS device has a conformal coating formed thereon to protect the MEMS device from corrosive gases and has a metal strip to allow for the formation of a metal seal between the MEMS device and a mounting plate or other device or structure to which the MEMS device is mounted.

[0025] Typically, precise control of the flow rate of the process gas used in the manufacturing process is advantageous for better process control and to allow for the satisfaction of precise process constraints. The low transient response rate of current MFCs, typically on the order of 100 microseconds or larger, is unsuitable for applications requiring precise control of gas dosage, such as the sequential delivery of small amounts of gas and pulses of one or more gases with pulse widths on the order of 100 milliseconds or smaller.

[0026] Embodiments of this invention 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 EtherCAT® plug-in modules (EPMs)) can more quickly control MFCs or independently actuated valves based on rapid flow feedback. Although various embodiments may utilize MEMS devices as the sole source of feedback, flow feedback from MFC devices 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).

[0027] In addition to flow feedback, MEMS devices can be advantageously used to provide rapid and accurate temperature measurements at any location on the gas supply line, including at the source, near the valve, near the inlet to the processing chamber (i.e., the delivery point), or inside the processing chamber. The temperature measurements can be monitored in real time by a processing device that can then send power output commands to heat the cells at different locations on the gas supply line.

[0028] Certain embodiments advantageously adapt the MEMS device for direct insertion into a gas flow path while protecting the MEMS device from the corrosive effects of the gas. For example, in some embodiments, a protective and non-conductive conformal coating is deposited onto the surface of the MEMS device exposed to gas during operation. For example, atomic layer deposition (ALD) or ion-assisted deposition (IAD) techniques can be used to form a conformal coating on at least a portion of the MEMS device. For example, ALD techniques achieve a conformal coating of substantially uniform thickness and zero porosity (i.e., no porosity) on all exposed surfaces of the component to be coated, including features with complex geometries and / or high aspect ratios. The coating can be plasma-resistant to reduce plasma interactions and improve the durability of the MEMS device without affecting its performance. The thin coating deposited with ALD maintains electrical properties and the relative shape and geometry of the MEMS device so as not to interfere with its functionality. The coating deposited with IAD can have relatively low film stress (e.g., compared to film stress caused by plasma spraying or sputtering). The IAD-deposited coating may additionally have a porosity of less than 1%, and in some embodiments less than about 0.1%. Post-coating heat treatment can be used to achieve improved coating properties. For example, it can be used to transform an amorphous coating into a crystalline coating with higher erosion resistance. Another example is improving the adhesion strength of the coating to the substrate by forming a reaction zone or transition layer therebetween.

[0029] Certain embodiments also advantageously allow the MEMS device to be mounted without the use of adhesive compounds. For example, in some embodiments, the MEMS device may be modified to include a metal strip that surrounds the region of the MEMS device between the sensor region and the interface region with which it makes electrical contact, wherein the metal strip is electrically isolated from other conductive parts of the MEMS device by a conformal coating formed on the MEMS device. The MEMS device may then be mounted to a metal mounting plate by brazing to form a metal seal between the metal strip of the MEMS device and the mounting plate.

[0030] Several embodiments herein relate to MFCs or components thereof used to limit 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 fans for medical use.

[0031] Figure 1 depicts a system 100 according to an embodiment of the present invention, the system including a processing chamber 101, a gas source 160, and a flow control device 200. The processing chamber 101 can be used in processes in which a corrosive plasma environment is provided. For example, the processing 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, ALD chambers, IAD chambers, etching chambers, or other types of processing chambers. In some embodiments, the processing chamber 101 may be any chamber used in an electronic device manufacturing system.

[0032] In one embodiment, the processing chamber 101 includes a chamber body 102 that encloses 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 a plurality of disc 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.

[0033] 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.

[0034] The exhaust port 126 may be defined in 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 processing chamber 101.

[0035] A gas source 160 may be coupled to a processing chamber 101 to provide processing and / or cleaning gas through a nozzle 130 to an internal volume 106 via a supply line 112. A flow control device 200 may be coupled to the gas source 160 and the processing chamber 101. The flow control device 200 may be used to measure and control the flow of gas from the gas source 160 to the internal volume 106. An exemplary flow control device 200 is described in more detail below with reference to Figure 2. In some embodiments, one or more gas panels 160 may be coupled to the processing chamber 101 to provide gas to the internal volume 106. In this embodiment, one or more flow control devices 200 may be coupled to each gas source 160 and the processing chamber 101. In other embodiments, a single flow control device 200 may be coupled to one or more gas panels 160. In some embodiments, the flow control device 200 may include a flow ratio controller to control the flow of gas to the processing chamber 101 (e.g., through one or more supply lines 112), or to other processing chambers.

[0036] The nozzle 130 may be supported on the sidewall 108 of the chamber body 102. The nozzle 130 (or cover) may open to allow access to the internal volume 106 of the processing chamber 101 and provide a seal for the processing chamber 101 when closed. A gas source 160 may be coupled to the processing chamber 101 to supply processing and / or cleaning gases through the nozzle 130 or cover and nozzle (e.g., through orifices in the nozzle or cover and nozzle) to the internal volume 106. The nozzle 130 may be used in processing chambers for dielectric etching (etching dielectric materials). The nozzle 130 may include a gas distribution plate (GDP) and may have a plurality of gas delivery orifices 132 (also referred to as channels) throughout the GDP. The 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 together with GDP bonded to an aluminum substrate or a cationized aluminum substrate. GDP can be made of Si or SiC and can be ceramic, such as Y2O3, Al2O3, Y3Al5O12 (YAG), etc.

[0037] For a processing chamber used for etching conductive materials, a cover may be used instead of a nozzle. The cover may include a central nozzle fitted into a central hole in the cover. The cover 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.

[0038] Examples of processing gases that can be used to process the substrate in the processing chamber 101 include halogen-containing gases such as C2F6, SF6, SiCl4, HBr, NF3, CF4, CHF3, CH2F3, F, NF3, Cl2, CCl4, BCl3, and SiF4, etc., and other gases such as O2 or N2O. The flow rate of any of these gases can be measured and adjusted by the flow control device 200. The distal plasma can be formed from any of these and / or other processing gases and subsequently delivered to the chamber 101 through the supply line 112 and through the flow control device 200. Thus, the distal plasma can be composed of: C2F6, SF6, SiCl4, HBr, NF3, CF4, CHF3, CH2F3, F, NF3, Cl2, CCl4, BCl3, and SiF4, etc., and other gases such as O2 or N2O. Examples of carrier gases include N2, He, Ar, and other gases that are inert to the treatment gas (e.g., non-reactive gases).

[0039] A substrate support assembly 148 is disposed within an internal volume 106 of a processing chamber 101 below the nozzle 130. 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 may protect the covered portion from exposure to plasma during processing. In one embodiment, the ring may be silicon or quartz. An inner liner may be coated on 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.

[0040] 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 such sensor devices may be used to monitor conditions near the reaction site.

[0041] In one embodiment, the substrate support assembly 148 includes a base 152 supporting the electrostatic chuck 150. The electrostatic chuck 150 further includes a thermally conductive substrate and an electrostatic disk bonded to the thermally conductive substrate by a bonding element, which in one embodiment may be a siloxane bonding element. The thermally conductive substrate 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 may 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.

[0042] Figure 2 depicts a flow control device 200 according to an embodiment of the present invention. The flow control device 200 may be configured to measure and control the mass flow rate of process gas and / or cleaning gas used in a manufacturing system, and thus can be considered a type of MFC. The flow control device 200 may be coupled to a gas source 160 and a chamber 101 via a gas flow channel 240. The gas flow channel may correspond to the supply line 112 in Figure 1. In some embodiments, the flow control device 200 may be integrated into a flow ratio controller or a pulsed mass flow system.

[0043] In some embodiments, the flow control device 200 may include at least a flow modulator 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 modulator 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).

[0044] In some embodiments, the flow modulator 210 is configured to restrict gas flow through the flow path 242 and may include one or more flow modulation valves, each of which may be an actuable valve, such as, for example, a solenoid valve or a piezoelectric valve. In some embodiments, the flow modulator includes other components besides valves, such as flow or temperature sensing components. In some embodiments, the flow modulator 210 serves as an MFC, such as a heat-based MFC, a pressure-based MFC, or a decay rate-based MFC.

[0045] In some embodiments, where the flow modulator 210 is used as a thermal-based MFC, the flow modulator 210 includes a capillary bypass channel branching from the gas flow channel 240. Temperature sensors at the beginning and end of the capillary are used to calculate (e.g., by means of the processing device 230 or an onboard processing device) a temperature increment that is proportional to the gas flow rate.

[0046] In some embodiments, the flow modulator 210 is used as a pressure-based MFC, and the flow modulator 210 includes two pressure transducers upstream and downstream of the flow modulation 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.

[0047] In some embodiments, the flow modulator 210 is used as a rate-attenuation-based MFC. The flow modulator 210 includes a valve for controlling gas flow into a predetermined volume of reservoir and a pressure sensor for measuring the attenuation pressure in the reservoir. The gas flow rate is proportional to the rate of pressure change.

[0048] In some embodiments, the sensor device 220 is disposed downstream of the flow modulator 210. The sensor device 220 may be a part of the flow modulator 210 (e.g., adjacent to the flow modulator 210), near the flow modulator 210 (e.g., within 10 cm of the flow modulator 210), near the inlet of the chamber 101 or the nozzle 130 (e.g., within 10 cm of the inlet), or within the chamber 101 (as shown in Figure 1 with respect to sensor device 170, such sensor devices may be the same as or similar to sensor device 220).

[0049] In some embodiments, the sensor device 220 includes a MEMS device 222 that may be configured to generate one or more signals in response to conditions of gas flow. For example, the 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 Figure 3. In some embodiments, the sensor device 220 is mounted to a gas flow channel 240 such that the MEMS device 222 is directly inserted into the flow path 242. The sensor device 220 is coupled to the gas flow channel such that a seal is formed to prevent gas leakage. In some embodiments, the sensor device 220 includes a mounting plate to which the MEMS device 222 is secured via a seal (e.g., a metal seal).

[0050] In some embodiments, the processing device 230 includes a central processing unit (CPU), a microcontroller, a programmable logic controller (PLC), a system-on-a-chip (SoC), a server computer, or other suitable type of computing device. The processing device 230 may be configured to execute programming instructions relating to the operation of the flow modulator 210. The processing device 230 receives feedback signals from the sensor device 220 and, where appropriate, the flow modulator 210, and calculates the temperature, flow rate, and / or other parameters of the gas flow. The processing device 230 further sends control signals to the flow modulator 210 based on the received feedback signals. In some embodiments, the processing device 230 is configured for high-speed feedback processing and may include, for example, an EPM. In some embodiments, the processing device is configured to execute a processing scheme, or one or more steps of a processing scheme, for a manufacturing process using chamber 101. For example, the scheme 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, the scheme can specify pulses of one or more gases.

[0051] Figures 3A and 3B respectively show a top view and a side view of an exemplary MEMS device 300 according to an embodiment of the present invention, which is manufactured using familiar semiconductor manufacturing techniques by a person skilled in the art. The MEMS device 300 may be the same as or similar to the MEMS device 222 described with respect to Figure 2. The overall dimensions of the MEMS device 300 can be characterized by the following: a length (L) from about 2 mm to about 10 mm, a width (W) from about 1 mm to about 5 mm, and a 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 that improves its aerodynamic properties. The tapered region may further define a cavity 306, such as a nanowire 308, on which a freestanding sensing element is suspended.

[0052] 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 nanowires 308. Electrodes 304 may be formed of one or more conductive metals. 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 electrode 304 may be encapsulated or formed through the interior of the elongated support structure 302 to protect electrode 304 from corrosion.

[0053] Figure 3C shows an enlarged view of a nanowire 308 suspended between two electrodes 304. 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, resulting in a freestanding nanowire 308 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 path for transmission. Such structures may be utilized if other continuous or discontinuous structures allow for impedance measurement across the line.

[0054] Nanowires 308 with a length (Lw) greater than their diameter or width / thickness are produced, and their dimensions are selected such that the nanowires 308 can deflect when exposed to low and high velocity gas flows. In some embodiments, the length of Lw 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, Lw is about 100,000 times greater than its diameter or width / thickness. In some embodiments, the nanowires 308 may have a circular or rectangular cross-section having a diameter or thickness / width of about 50 nanometers to about 500 nanometers. Other dimensions will be recognized by those skilled in the art.

[0055] 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 anemometry (CCA) device, wherein a fixed current flows through nanowires 308 to raise the temperature of nanowires 308, thereby increasing resistance. During operation, gas flow above the lines removes heat from nanowires 308 via convection, and the resistance at constant current and constant gas velocity will reach a steady state. 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.

[0056] As another example, the MEMS device 300 may be configured for elastic filament velocimetry (EFV). The gas velocity can be correlated with the strain in the nanowire 308 attributable to the deflection of the gas flow. In this operation, a small current can pass 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. The change in resistance can be correlated with the gas flow rate.

[0057] In some embodiments, nanowires 308 may be coupled onto a MEMS device 300, wherein two or more nanowires have separate electrode pairs, each of which can be used to separately perform CCA or EFV. In some embodiments, the two or more nanowires may be oriented in a non-collinear orientation.

[0058] Figures 4A and 4B respectively show a top view and a side view of an exemplary MEMS device 400 adapted for use in a flow control device (e.g., flow control device 200) according to an embodiment of the present invention. The MEMS device 400 corresponds to a modified version of the MEMS device 300, which includes a metal strip 410 and may also include a non-conductive conformal coating 420 (described below with reference to Figure 4C). An elongated support structure 302 includes three regions. The first region is an interface region 402 for coupling the MEMS device 400 to an external device (such as a processing device 230). Electrodes 304 may be used as electrical contacts for interfacing with such external devices, thereby forming a closed circuit during operation.

[0059] The second region is a coupling region 404 serving as a location where the MEMS device 400 can be coupled or mounted to another structure (such as a mounting plate). A metal strip 410 is located at the coupling region, which is substantially positioned at the center of the elongated support structure 302. In some embodiments, the metal strip 410 is located at another suitable location on the elongated support structure 302 if it does not overlap the cavity 306 or obstruct the electrical coupling of the electrode 304.

[0060] In some embodiments, the metal strip 410 is formed of nickel, aluminum, another non-corrosive metal, or an alloy thereof. In some embodiments, the metal strip 410 may be deposited using techniques such as physical vapor deposition (PVD) or electroplating to deposit a continuous conformal layer that surrounds a portion of the elongated support structure 302. Figures 4A and 4B show the conformal layer covering multiple surfaces of the elongated support structure 302. In Figure 4A, a dashed line passing through the metal strip 410 is illustrated as indicating that the electrode 304 is disposed below the metal strip 410. In some embodiments, an insulating layer (e.g., SiO2) is deposited prior to the metal strip 410 to separate the metal strip 410 from the elongated support structure 302 and the electrode 304 to prevent short circuits between the electrodes 304 during operation. In some embodiments, the thickness of the metal strip 410 is from 50 micrometers to 500 micrometers. In some embodiments, the width of the metal strip (i.e., the width measured along the longitudinal axis of the elongated support structure 302) is from 0.5 millimeters to 2 millimeters. In some embodiments, the metal strip 410 does not form a continuous layer and may be deposited, for example, as discrete islands of metallic material.

[0061] In some embodiments, the MEMS device 400 further includes a non-conductive conformal coating 420, a coupling region 404, and / or a sensor region 406 on one or more surfaces or portions thereof of the interface region 402. In some embodiments, the conformal coating 420 covers some or all of the sensor region 406, including some or all of the nanowires 380. In other embodiments, the conformal coating 420 covers the sensor region 406 but not the nanowires 380. In other embodiments, the conformal coating 420 covers only the portion of the MEMS device 400 exposed to gas flow when the MEMS device 400 is inserted into a gas flow channel, as discussed below with respect to Figures 5A through 5G.

[0062] In some embodiments, the conformal coating 420 covers at least a portion of the coupling region 404 and / or the interface region 402. In some embodiments, a metal strip 410 is disposed over the conformal coating 420, wherein the conformal coating 420 serves as an insulating layer between the metal strip 410 and the electrode 304. In this embodiment, the conformal coating 420 is deposited prior to the deposition of the metal strip 410.

[0063] Figure 4C shows a cross-sectional view of an enlarged region of the MEMS device 400 to illustrate conformal coatings 420 on multiple surfaces of the elongated support structure 302. In some embodiments, the conformal coating 420 is deposited using techniques such as ALD, IAD, low-pressure plasma spray (LPPS), chemical vapor deposition (CVD), plasma spray chemical vapor deposition (PS-CVD), sputtering, combinations thereof, or other techniques suitable for forming the conformal coating or modifications thereof. In some embodiments, the conformal coating 420 comprises a ceramic material resistant to corrosion by process gases or reactive substances. For example, in some embodiments, the conformal coating may comprise a plasma-resistant ceramic coating comprising rare earth ceramics selected from: Y₂O₃, YZrO, YxZryOz, YZrOF, Y₃Al₅O₁₂, Y₄Al₂O₉, YF₃, YxOyFz, YOF, Er₂O₃, Er₃Al₅O₁₂, ErF₃, ExOyFz, ErOF, La₂O₃, Lu₂O₃, Sc₂O₃, ScF₃, ScOF, Gd₂O₃, Sm₂O₃, Dy₂O₃, Y₂O₃-ZrO₂ solid solutions, ceramics comprising Y₂Al₄O₉ and Y₂O₃-ZrO₂ solid solutions, or combinations thereof. In some embodiments, the conformal coating 420 is substantially uniform, conformal, and non-porosity.

[0064] As shown in Figure 4C, in some embodiments, the conformal coating 420 comprises a plurality of sequentially deposited layers 422A-422D. In some embodiments, more or fewer layers may be provided compared to those shown, and the number of layers may vary from 1 to 100, up to 500, or more. For example, multiple atomic-level or near-atomic-level thin layers may be deposited, for example, using an ALD. In some embodiments, the composition of each of layers 422A-422D may be alternating. In some embodiments, the total thickness of the conformal coating 420 may vary from 10 nanometers to 300 nanometers.

[0065] Figures 5A through 5E illustrate mounting a MEMS device 400 to an exemplary mounting plate 500 according to an embodiment of the present invention. The mounting plate 500 may be in the form of a thin, flat sheet of metal, although other suitable shapes such as circular, rectangular, etc. are contemplated. In some embodiments, the thickness of the mounting plate may vary from 500 micrometers to 5 millimeters. The mounting plate 500 may be formed of, for example, stainless steel, a nickel alloy (e.g., Hastelloy® C-276 alloy, which is an alloy of nickel, molybdenum, and chromium), or another suitable material. The mounting plate 500 includes a slot 502 shaped to receive the MEMS device 400 formed therethrough. In some embodiments, the slot 502 is sized so as not to physically contact the MEMS device 400 (or at least a portion of the MEMS device 400). The MEMS device 400 may be inserted into the slot 502, as shown in Figures 5C and 5D, and subsequently mounted to the mounting surface 500B of the mounting plate 500, for example, by means of a seal 510 formed between the metal strip 410 and the mounting plate 500. The seal 510 is an airtight seal used to prevent gas leakage when the mounting plate 500 and the components of the MEMS device 400 are further coupled to a gas flow channel (such as gas flow channel 520). In some embodiments, the seal 510 is a metal seal formed, for example, by brazing or welding.

[0066] Figure 5F shows a cross-sectional view of the assembly of the mounting plate 500 and the MEMS device 400 coupled to the gas flow channel 520, which may be similar in construction to that shown in Figure 2, wherein the sensor device 220 is coupled to the gas flow channel 240. In some embodiments, the gas flow channel 520 is a gas line, a branch channel of a gas line, or a separate component having an inlet and an outlet for assembly to a gas line. In some embodiments, the mounting plate is integrally formed with the gas flow channel 520. In some embodiments, the mounting plate 500 is mechanically coupled to the gas flow channel.

[0067] When the mounting plate 500 is coupled to the gas flow channel 520, the MEMS device 400 is inserted through the slot 522 of the gas flow channel 520, such that the nanowire 308 is positioned within the flow path 530 of the gas flow channel 520 (which is in a direction orthogonal to the drawing plane). When the mounting plate 500 is in the form of a planar structure, as shown, a rubber O-ring 540 may be provided between the gas-facing surface 500A of the mounting plate 500 and the gas flow channel 520 to form a seal. The wire 550 may be mechanically coupled or soldered, for example, to the electrode 304 of the MEMS device 400 to operatively couple the MEMS device 400 to, for example, the processing device 230.

[0068] Figure 6 illustrates a method 600 for adapting a sensor device for use in a flow control device according to an embodiment of the present invention. At block 610, a sensor device, such as sensor device 220 described above with respect to Figure 2, is provided. In some embodiments, the sensor device includes a MEMS device, such as MEMS device 222 or 300 described with respect to Figures 2 through 5. In some embodiments, the sensor device includes an elongated support structure comprising an interface region (e.g., interface region 402), a sensor region (e.g., sensor region 406), and a coupling region (e.g., coupling region 404) located between the interface region and the sensor region. The sensor region includes a freestanding sensing element, such as a nanowire (e.g., nanowire 308), suspended at the sensor region.

[0069] At block 620, a conformal coating (e.g., conformal coating 420) is deposited onto the sensor device to at least partially cover the sensor area. In some embodiments, the conformal coating is a non-conductive material, such as a non-conductive ceramic material. In some embodiments, the conformal coating covers at least a portion of the nanowires (e.g., nanowire 308). In other embodiments, the conformal coating covers the sensor area and does not cover or minimally covers the nanowires.

[0070] In some embodiments, the conformal coating is deposited using ALD, IAD, LPPS, CVD, PS-CVD, or sputtering one or more deposition methods. In some embodiments, the conformal coating comprises rare earth ceramics selected from the following: Y2O3, YZrO, YxZryOz, YZrOF, Y3Al5O12, Y4Al2O9, YF3, YxOyFz, YOF, Er2O3, Er3Al5O12, ErF3, ExOyFz, ErOF, La2O3, Lu2O3, Sc2O3, ScF3, ScOF, Gd2O3, Sm2O3, Dy2O3, Y2O3-ZrO2 solid solution, ceramics comprising Y2Al4O9 and Y2O3-ZrO2 solid solutions, or combinations thereof. In some embodiments, the conformal coating comprises multiple layers. In some embodiments, the conformal coating has a thickness of about 10 nanometers to about 300 nanometers.

[0071] At block 630, a metal strip (e.g., metal strip 410) is deposited on the sensing device (i.e., on the MEMS device). In some embodiments, the metal strip is deposited using one or more depositions such as PVD or electroplating. In some embodiments, the metal strip forms a continuous conformal layer that surrounds a portion of an elongated support structure. In some embodiments, the metal strip is deposited over a conformal coating. In other embodiments, the conformal coating is not present at the location where the metal strip is deposited or otherwise formed.

[0072] At block 640, the sensor device is secured to a mounting plate (e.g., mounting plate 500). In some embodiments, the sensor device is secured to the mounting plate by forming a metal seal (e.g., seal 510) between the metal strip and the mounting plate, for example by brazing or soldering. In some embodiments, the sensor device is inserted into a gas flow channel and the mounting plate is mechanically coupled to the gas flow channel (as shown in Figure 5F).

[0073] For the sake of simplicity, the method of this invention is depicted and described as a series of actions. However, the actions according to this invention can occur in any order and / or simultaneously, and other actions are not presented or described herein. Furthermore, not all the actions shown are required to implement the method according to the disclosed intent. In addition, those skilled in the art will understand and recognize that the method can alternatively be represented by a state diagram or events as a series of interrelated states. Furthermore, it should be understood that the method disclosed in this specification can be stored on an article of art to facilitate the transmission and delivery of instructions for performing such methods to a computing device. As used herein, the term "article of art" is intended to encompass a computer program accessible from any computer-readable device or storage medium.

[0074] Figure 7 illustrates a graphical representation of a machine in an exemplary form of computer system 700, wherein an executable set of instructions (e.g., for causing the machine to perform any one or more methodologies discussed herein) is provided. In alternative embodiments, the machine may be connected (e.g., networked) to other machines in a LAN, WAN, intranet, extranet, or internet. The machine may operate within the capacity of 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 another machine. Additionally, although only a single machine is shown, the term "machine" should also be considered to include any set of machines that independently or jointly execute a set of instructions (or multiple sets of instructions) to perform any one or more methodologies discussed herein. Some or all of the components of the computer system 700 may be utilized or described by any electronic component described herein (e.g., any electronic component utilized by the operation of the processing device 230 or the combined chamber 101 or the flow modulator 210).

[0075] An exemplary computer system 700 includes a processing device (processor) 702, main memory 704 (e.g., ROM, flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM), or Rambus DRAM (RDRAM), etc.), static memory 706 (e.g., flash memory, static random access memory (SRAM), etc.), and data storage device 720, which communicate with each other via bus 710.

[0076] 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 a combination of instruction sets. Processor 702 may also be one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), network processors, or the like. Processor 702 is configured to execute instructions 740 for performing the operations discussed herein.

[0077] 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 digital generation device 722 (e.g., a speaker).

[0078] The power device 718 can monitor the power level of the battery used to power the computer system 700 or one or more of its components. The power device 718 can provide one or more interfaces for providing indications of: power level, a time window before shutting down the 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 of the power device 718 can be accessed remotely (e.g., via a network connection to a remote backup management module). In some implementations, the battery used by the power device 718 can be an uninterruptible power supply (UPS) for the computer system 700, either locally or remotely. In this implementation, the power device 718 can provide information about the power level of the UPS.

[0079] Data storage device 720 may include computer-readable storage medium 724 (e.g., non-transitory computer-readable storage medium) storing one or more sets of instructions 740 (e.g., software) embodying any one or more methodologies or functions described herein. These instructions 740 may also be wholly or at least partially housed within the main memory 704 and / or the processor 702 by means of a computer system 700, main memory 704, and processor 702, which also constitute 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., centralized or distributed databases, and / or associated cache memory and servers) storing one or more sets of instructions 740.

[0080] 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 case that embodiments of this case can be practiced without such specific details. Although specific embodiments have been described herein, it should be understood that such 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 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 case, 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 case.

[0081] 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 such examples are not limiting, allowing for the use of other embodiments and modifications 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 those 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. Furthermore, unless otherwise indicated, the conjunction "or" herein is intended to have an inclusive meaning where appropriate; 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".

[0082] The terms “example” or “exemplary” are used herein to mean as an example, instance, or illustration. Any form or design described herein as an “example” or “exemplary” is not to be construed as superior or advantageous compared to other forms 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%.

[0083] Furthermore, the article "a / an" as used herein and in the appended claims should generally be interpreted as meaning "one or more," unless otherwise stated or clearly understood from the context involving the 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.

[0084] Some parts of embodiments may be presented with respect to algorithmic and symbolic representations of operations on data bits within computer memory. Such algorithms and representations are the manner in which a skilled person in the field of data processing uses to most effectively communicate the substance of his or her work to other skilled persons in the field. Algorithms are in this paper and are generally considered to be self-consistent sequences of steps leading to the desired outcome. The steps are required physical amount of physical manipulation of those. This usually, although not mandatory, these quantities take the form of electrical or magnetic signals capable of being stored, transmitted, combined, compared, or otherwise manipulated. Mainly for general reasons, it is convenient to refer to such signals as bits, values, elements, symbols, characters, terms, numbers, or similar sometimes confirmed.

[0085] It should be remembered, however, that all such and similar terms will be associated with appropriate physical quantities and merely convenient markers applied to such quantities. Unless otherwise specifically stated, as evident from the following discourse, it will be understood that, throughout the description, use of terms such as “receive,” “retrieve,” “send,” “compute,” “generate,” “process,” “reprocess,” “add,” “subtract,” “multiply,” “divide,” “optimize,” “calibrate,” “detect,” “enforce,” “identify,” “det A discourse to modify,” “transform,” “apply,” “cause,” “store,” “compare,” or similar refers to a computer system or similar electronic computing device that manipulates and transforms data expressed as registers and physical (electronic) quantities in memory of a computer system into memory or registers of a computer system or other such information storage, transmission, or display of physical quantities of other data within a device.

[0086] Furthermore, notwithstanding the fact that the present case has been described herein in the context of a particular implementation in a particular setting for a particular purpose, a general skilled person in the art will recognize that its usefulness is not limited to this and the present case can be beneficially realized in any number of environments for any number of purposes. Thereby, the scope of the applied patent shall be construed in the light of the complete breadth and spirit of the present case as described herein together with the complete category of equivalents such as the scope of such application is granted. [Brief explanation of the diagram]

[0007] In this case, it is shown by example but not limitingly in the schematic of the accompanying drawings that the same component symbols in the accompanying drawings indicate the same components. It should be noted that in the present case, different references to “one (an)” or “one (one)” embodiments do not have to be the same embodiments and such reference means at least one.

[0008] Figure 1 illustrates an exemplary system according to an embodiment of the present invention, including a processing chamber, a gas source, and a flow control device.

[0009] Figure 2 illustrates an exemplary flow control device according to an embodiment of this case.

[0010] Figure 3A shows a top view of an exemplary MEMS device according to an embodiment of this case.

[0011] Figure 3B shows a side view of an exemplary MEMS device according to an embodiment of this case.

[0012] Figure 3C illustrates a stand-alone sensing element of an exemplary MEMS device according to an embodiment of the present case.

[0013] Figure 4A shows a top view of an exemplary MEMS device adapted for use in a flow control device according to an embodiment of the present case.

[0014] Figure 4B shows a side view of an exemplary MEMS device adapted for use in a flow control device according to an embodiment of this case.

[0015] Figure 4C shows a cross-sectional view of a conformal coating formed on the surface of an exemplary MEMS device according to an embodiment of the present case.

[0016] Figure 5A shows a top view of an exemplary mounting plate according to an embodiment of the present case.

[0017] Figure 5B shows a side cross-sectional view of an exemplary mounting plate according to an embodiment of the present case.

[0018] Figure 5C illustrates an exemplary MEMS device prior to insertion through a slot in an exemplary mounting plate according to an embodiment of the present case.

[0019] Figure 5D illustrates an exemplary MEMS device inserted into a slot of an exemplary mounting plate according to an embodiment of the present case.

[0020] Figure 5E illustrates an exemplary MEMS device mounted in a slot of an exemplary mounting plate by means of a metal seal according to an embodiment of the present invention.

[0021] Figure 5F illustrates an exemplary MEMS device coupled to a gas flow channel via an exemplary mounting plate according to an embodiment of the present invention.

[0022] Figure 6 illustrates a method for adjusting a sensor device in a flow control device according to an embodiment of the present invention.

[0023] Figure 7 is a block diagram of a computer system used according to an embodiment of the present invention. [Biomaterial Storage]

[0088] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A sensor device comprising: an elongated support structure including an interface region, a sensor region, and a coupling region between the interface region and the sensor region, wherein the elongated support structure is made of a non-solderable material; electrodes disposed on the interface region; a freestanding sensing element suspended in the sensor region, wherein the freestanding sensing element is electrically coupled to the electrodes; a conformal strip metal coating surrounding the coupling region, wherein the conformal strip metal coating is tightly sealed to the coupling region of the elongated support structure, and wherein the conformal strip metal coating is solderable and allows the elongated support structure to be soldered to a mounting plate to form a metal seal between the sensor device and the mounting plate; and a non-conductive conformal coating comprising a plasma-resistant ceramic material on at least a portion of the sensor region.

2. The sensing device as claimed in claim 1, wherein the sensing device includes a silicon-based microelectromechanical system (MEMS) device.

3. The sensor device as claimed in claim 1, wherein the non-conductive conformal coating has a thickness of about 10 nanometers to about 300 nanometers.

4. The sensor device as claimed in claim 1, wherein the freestanding sensing element includes a nanowire, and wherein the sensing region defines a cavity on which the nanowire is suspended.

5. The sensor device as claimed in claim 4, wherein the nanowire comprises platinum, and wherein the nanowire is at least partially coated with the non-conductive conformal coating.

6. The sensor device as claimed in claim 1, wherein the electrodes are formed on or within the coupling region, and wherein the non-conductive conformal coating forms an insulating layer between the conformal strip metal coating and the electrodes.

7. The sensor device as claimed in claim 1, wherein the mounting plate further comprises: a gas-facing surface and a mounting surface opposite the gas-facing surface, the mounting plate having a slot formed therethrough, wherein: The elongated support structure is disposed in the slot such that the sensor region extends from the gas-facing surface and the coupling region extends from the mounting surface, and the elongated support structure is secured to the mounting plate at the coupling region by a metal seal formed between the conformal strip metal coating and the mounting surface of the mounting plate.

8. The sensor device as claimed in claim 1, wherein the conformal strip metal coating has a thickness of 50 micrometers to 500 micrometers and a width of 0.5 millimeters to 2 millimeters.

9. A flow control device comprising: a gas flow channel defining a gas flow path; a flow modulation valve configured to modulate the gas flow in the gas flow channel; and a sensing device comprising: an elongated support structure, wherein the elongated support structure is made of a non-solderable material. A sensor region, on the elongated support structure, includes a non-conductive conformal plasma-resistant ceramic coating and a freestanding sensing element disposed within the gas flow path; and a coupling region, on the elongated support structure, includes a conformal strip metal coating sealing the sensor device to the gas flow channel, wherein the conformal strip metal coating is tightly sealed to the coupling region, and wherein the conformal strip metal coating is brazable and allows the elongated support structure to be brazed to a mounting plate or an external region of the gas flow channel to form a metal seal between the sensor device and the mounting plate or the external region of the gas flow channel; and a processing device operatively coupled to the flow modulation valve and the sensor device, the processing device being configured to adjust the flow modulation valve based on a signal received from the sensor device.

10. The flow control device as claimed in claim 9, wherein the sensing device is a silicon-based microelectromechanical system (MEMS) device.

11. The flow control device as claimed in claim 9, wherein the stand-alone sensing element comprises a nanowire.

12. The flow control device as claimed in claim 9, wherein the stand-alone sensing element is at least partially coated with the non-conductive conformal plasma-resistant ceramic coating.

13. The flow control device as claimed in claim 9, wherein the elongated support structure is disposed within a slot formed in the gas flow path.

14. The flow control device as claimed in claim 13, wherein the sensor device includes a metal strip surrounding a portion of the elongated support structure extending from the slot of the gas flow path, wherein the sensor device is secured to the gas flow path by a mounting plate mechanically coupled to the gas flow path.

15. The flow control device as claimed in claim 13, wherein the sensor device includes a metal strip surrounding a portion of the elongated support structure extending from the slot of the gas flow channel, wherein the sensor device is secured to the gas flow path by the outer region of the gas flow channel.

16. A method of adapting a sensor device to a flow control apparatus, the method comprising the steps of: providing the sensor device, comprising the steps of: an elongated support structure including an interface region, a sensor region, and a coupling region located between the interface region and the sensor region, wherein the elongated support structure is made of a non-solderable material; and a freestanding sensing element suspended in the sensor region; depositing a conformal coating on the sensor device to at least partially cover the sensor region, the conformal coating comprising a plasma-resistant ceramic material; and depositing a conformal strip metal coating on the sensor device to surround the coupling region, wherein the conformal strip metal coating is tightly sealed to the coupling region of the elongated support structure, and wherein the conformal strip metal coating is solderable and allows the elongated support structure to be soldered to a mounting plate to form a metal seal between the sensor device and the mounting plate.

17. The method as described in claim 16, wherein the conformal coating is deposited using an ion-assisted deposition process, and wherein the plasma-resistant ceramic material is non-conductive.

18. The method as described in claim 16 further comprises the step of: securing the sensor device to the mounting plate by forming the metal seal between the conformal strip metal coating and the mounting plate.

19. The method as described in claim 18, wherein the metal seal is formed by brazing.

20. The method as described in claim 18 further comprises the steps of: inserting the sensor device into a gas flow channel; and mechanically coupling the mounting plate to the gas flow channel.

Images