Method, system, and apparatus for performing calibration operations on multiple mass flow controllers (MFCs) in a substrate processing system.

Abstract

To provide a method, a system, and a device, for executing a calibration operation of a plurality of mass flow amount controllers (MFC) of a substrate processing system.SOLUTION: A method for generating a flow amount curvature in which a range of a target flow amount over a plurality of setting points is corrected, contains a setting of a priority order to a plurality of MFCs in order to a calibration operation. The setting of the priority order, contains a ranking of the plurality of MFCs in a rank list in accordance with a specification of an operation time of each MFC of the plurality of MFCs an operation time of each MFC. The method also contains an execution of the calibration operation of the plurality of MFCs during an idle time of a substrate processing system in accordance with the rank list.SELECTED DRAWING: Figure 3A

Description

Technical Field

[0001]

[0001] Multiple aspects generally relate to a method, system, and apparatus for performing calibration operations of multiple mass flow controllers (MFCs) of a substrate processing system. In one aspect, a flow rate curve corrected for a range of target flow rates over multiple set points is generated.

Background Art

[0002]

[0002] Mass flow controllers (MFCs) used in substrate processing operations may have several problems. For example, an MFC may include drift, leak, and / or shift-on-zero. Drift means that the MFC no longer supplies the same mass flow rate under the same operating conditions. A leak means that there is a flow rate through the MFC even when the MFC is set to operating conditions where flow should not occur. Shift-on-zero means that the MFC indicates that there is a flow rate through the MFC, but in fact there is no flow rate through the MFC.

[0003]

[0003] Attempts to address the above problems involve substantial expenditures of cost and human effort, substantial machine downtime, and substantial operation delays, and do not accurately consider the entire range of operating flow rates at which the MFC operates. Furthermore, if the problems cannot be addressed, it may affect processing results (such as the thickness of the deposited film or the quality of the deposited film), and may inhibit device performance. The effort to detect drift is not rewarded, and it may not be known until the characteristics of the processed substrate are measured. Also, the measurement or detection of drift may be inaccurate.

[0004]

[0004] Therefore, there is a need for improved methods, systems, and apparatuses that facilitate automatically correcting a mass flow controller (MFC), accurately correcting the MFC over a range of operating flow rates, reducing expenditures of cost and human effort, reducing machine downtime, and shortening operation delays. [Overview of the Initiative]

[0005]

[0005] Multiple embodiments relate more broadly to methods, systems, and apparatus for performing calibration operations on multiple mass flow controllers (MFCs) in a substrate processing system. In one embodiment, a modified flow curve is generated for a range of target flow rates across multiple setpoints. In one embodiment, the calibration operation is used to automatically correct the multiple MFCs.

[0006]

[0006] In one embodiment, a method for performing calibration operations on multiple mass flow controllers (MFCs) of a substrate processing system includes prioritizing the multiple MFCs for calibration operations. Prioritizing includes identifying the operating time of each of the multiple MFCs and ranking the multiple MFCs in a ranking list according to the operating time of each MFC. The method includes performing calibration operations on the multiple MFCs during idle time of the substrate processing system according to the ranking list. The calibration operation includes setting a first MFC to flow mode and flowing gas through the first MFC at a target flow rate. The calibration operation includes leading the gas to a mass flow verifier and changing the target flow rate of the gas one by one to a plurality of flow rates corresponding to a plurality of setpoints. The calibration operation includes using the mass flow verifier to verify the measured flow rate of the gas at each of the plurality of setpoints.

[0007]

[0007] In one embodiment, a non-transient computer-readable medium for performing calibration operations on multiple mass flow controllers (MFCs) of a substrate processing system includes an instruction. When the instruction is executed, it causes a plurality of operations to be performed. The plurality of operations include prioritizing the plurality of MFCs for calibration operations. Prioritizing includes specifying the operating time of each of the plurality of MFCs and ranking the plurality of MFCs in a rank list according to the operating time of each MFC. The plurality of operations include performing calibration operations on the plurality of MFCs during idle time of the substrate processing system according to the rank list. The calibration operation includes setting a first MFC to flow mode and flowing gas through the first MFC at a target flow rate. The calibration operation includes directing the gas to a mass flow verifier and changing the target flow rate of the gas one by one to a plurality of flow rates corresponding to a plurality of setpoints. The calibration operation includes using the mass flow verifier to verify the measured flow rate of the gas at each of the plurality of setpoints.

[0008]

[0008] In one embodiment, the substrate processing system includes a processing chamber that includes a processing space. The substrate processing system includes a gas circuit coupled to the processing chamber. The gas circuit includes a plurality of mass flow controllers (MFCs), with one or more supply lines coupled between the processing chamber and the plurality of MFCs, and a diversion line coupled between the plurality of MFCs and a mass flow meter. The substrate processing system includes a controller. The controller includes an instruction command. When the instruction command is executed, it causes a plurality of operations to be performed. The plurality of operations include prioritizing the plurality of MFCs for calibration operations. Prioritizing includes specifying the operating time of each of the plurality of MFCs and ranking the plurality of MFCs in a rank list according to the operating time of each MFC. The plurality of operations include performing calibration operations on the plurality of MFCs during idle time of the substrate processing system according to the rank list. The calibration operation includes setting a first MFC to flow mode and flowing gas through the first MFC at a target flow rate. The calibration procedure involves introducing the gas to a mass flow verifier and varying the target gas flow rate one by one to multiple flow rates corresponding to multiple setpoints. The calibration procedure also involves using the mass flow verifier to verify the measured gas flow rate at each of the multiple setpoints.

[0009]

[0009] To allow for a more detailed understanding of the above-mentioned features of the Disclosure, a more specific description of the Disclosure, which has been briefly summarized above, can be given by reference to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate exemplary embodiments and should not be considered limiting in scope, and the Disclosure may permit other equally effective embodiments. [Brief explanation of the drawing]

[0010] [Figure 1]

[0010] This is a schematic cross-sectional view of a substrate processing system having a processing chamber according to one embodiment. [Figure 2]

[0011] This is a schematic cross-sectional view of a mass flow controller (MFC) according to one embodiment. [Figure 3A]

[0012] This is a schematic block diagram of a method for performing calibration operations on multiple mass flow controllers (MFCs) of a substrate processing system according to one embodiment. [Figure 3B]

[0013] This is a schematic block diagram of performing the calibration operation shown in Figure 3A according to one embodiment. [Figure 4]

[0014] This is a schematic diagram of a graph according to one embodiment. [Modes for carrying out the invention]

[0011]

[0015] To facilitate understanding, the same reference numerals were used where possible to indicate identical elements common to the figures. It is believed that elements and features of one embodiment can be usefully incorporated into several other embodiments without additional description.

[0012]

[0016] Multiple embodiments relate more broadly to methods, systems, and apparatus for performing calibration operations on multiple mass flow controllers (MFCs) in a substrate processing system. In one embodiment, a modified flow curve is generated for a range of target flow rates across multiple setpoints.

[0013]

[0017] Figure 1 is a schematic cross-sectional view of a substrate processing system 101 having a processing chamber 100 according to one embodiment. The processing chamber 100 is configured for epitaxial deposition processing operations. One or more substrates can be processed using the processing chamber 100, including epitaxial deposition of material onto the upper surface of a substrate 125. Among its components, the processing chamber 100 may include an array of radiant heating lamps 102 for heating the back side 104 of a substrate support 106 placed inside the processing chamber 100. The substrate support 106 may be a disk-shaped substrate support 106, as shown, or a ring-shaped substrate support (having a central opening). The ring-shaped substrate support supports the substrate from the edges of the substrate 125 to facilitate the substrate's exposure to the thermal radiation of the lamps 102.

[0014]

[0018] The substrate support 106 is positioned within the processing chamber 100 between the upper dome 128 and the lower dome 114. The upper dome 128, the lower dome 114, and the base ring 136 positioned between the upper dome 128 and the lower dome 114 generally define the internal region of the processing chamber 100. The substrate 125 is transported into the processing chamber 100 through the loading port and placed on the substrate support 106.

[0015]

[0019] The substrate support 106 is supported by a central shaft 132. The central shaft 132 moves the substrate 125 vertically 134 during loading and unloading, and in some cases during processing of the substrate 125. The substrate support 106 is shown in the lifted processing position in Figure 1, but may be moved vertically to a loading position below the processing position by an actuator coupled to the central shaft 132. When lowered to the processing position, the lift pins 105 contact the substrate 125 and lift the substrate 125 from the substrate support 106. The robot may then enter the processing chamber 100 to engage with the substrate 125 and remove the substrate 125 from the processing chamber 100 through the loading port. The substrate support 106 may then be actuated vertically to the processing position, placing the substrate 125 on the front side 110 of the substrate support 106 with the device side 116 of the substrate 125 facing upward.

[0016]

[0020] While positioned in the processing location, the substrate support 106 divides the internal space of the processing chamber 100 into a processing space 156 above the substrate 125 and a purge gas space 158 below the substrate support 106. During processing, the substrate support 106 is rotated by a central shaft 132 to minimize the effects of spatial unevenness of heat and process gas flow within the processing chamber 100, thereby promoting uniform processing of the substrate 125. To absorb radiant energy from the lamp 102 and conduct radiant energy to the substrate 125, the substrate support 106 may be formed from silicon carbide or silicon carbide-coated graphite. The central window portion of the upper dome 128 and the lower part of the lower dome 114 are formed from an optically transparent material such as quartz. The thickness and degree of curvature of the upper dome 128 may be configured to provide flatter shape dimensions for uniform flow within the processing chamber 100.

[0017]

[0021] The array of lamps 102 may be positioned adjacent to and below the lower dome 114 in an optimally desired configuration identified around the central shaft 132, so as the process gas passes over various areas of the substrate 125, the temperature of those areas can be independently controlled. This facilitates the epitaxial deposition of material onto the device side 116 (e.g., the top surface) of the substrate 125. The deposited material may include gallium arsenide, gallium nitride, or aluminum gallium nitride. In one embodiment, which may be combined with several other embodiments, an array of radiant heating lamps, such as lamps 102, may be positioned on the upper dome 128.

[0018]

[0022] Lamp 102 may be configured to include a light bulb configured to heat a substrate 125 to a temperature in the range of approximately 200 degrees Celsius to approximately 1600 degrees Celsius. Each lamp 102 is coupled to a switchboard, and power is supplied to each lamp 102 via the switchboard. The lamps 102 are housed in a lamp head 145, which may be cooled during or after processing by a cooling fluid introduced, for example, into a channel 149 located between the lamps 102. Partly due to the proximity of the lamp head 145 to the lower dome 114, the lamp head 145 cools the lower dome 114 conductively and radiatively. The lamp head 145 may also cool the lamp walls and reflector walls around the lamps 102. Alternatively, the lower dome 114 may be cooled convectivally. Depending on the application, the lamp head 145 may or may not be in contact with the lower dome 114.

[0019]

[0023] Optionally, a circular shield 167 may be positioned around the substrate support 106 and surrounded by a liner assembly 163. The shield 167 prevents or minimizes thermal / optical noise leakage from the ramp 102 to the device side 116 of the substrate 125, while providing a preheating zone for process gases. The shield 167 may be fabricated from chemical vapor deposition (CVD) SiC, SiC-coated sintered graphite, grown SiC, opaque quartz, coated quartz, or any similar and suitable material resistant to chemical destruction by process gases and purge gases.

[0020]

[0024] The liner assembly 163 is sized to be nested within or surrounded by the inner circumference of the base ring 136. The liner assembly 163 shields the internal space (e.g., the processing space 156 and the purge gas space 158) from the metal walls of the processing chamber 100. Although the liner assembly 163 is shown as a single unit, the liner assembly 163 may include one or more liners having different configurations. As a result of backside heating of the substrate 125 from the substrate support 106, the use of the optical pyrometer 118 for temperature measurement / control on the substrate support 106 becomes feasible. Temperature measurement by the optical pyrometer 118 may also be performed relative to the device side 116 of the substrate 125.

[0021]

[0025] Optionally, the reflector 122 may be positioned outside the upper dome 128 to reflect light radiating from the substrate 125 back to the substrate 125. The reflector 122 may be secured to the upper dome 128 using a clamping ring 130. The reflector 122 may be made of a metal such as aluminum or stainless steel. Reflection efficiency may be improved by coating the reflector area with a highly reflective coating such as gold. The reflector 122 may have one or more channels 126 connected to a cooling source. The channels 126 connect to passages formed on the side of the reflector 122 for cooling the reflector 122. The passages may be configured to carry a flow of fluid such as water and may run horizontally along the side of the reflector 122.

[0022]

[0026] The substrate processing system 101 includes a gas circuit 180. The gas circuit 180 includes a plurality of mass flow controllers (MFCs) 181a to 181d. Each of the MFCs 181a to 181d is coupled to a respective gas source 182a to 182d for supplying gas to the respective MFCs 181a to 181d. One or more supply lines 183a to 183d (four are shown) are coupled between the MFCs 181a to 181d and the processing chamber 100 to supply gas from the MFCs 181a to 181d to the processing space 156 and / or the purge gas space 158. One or more shunt lines 184 (one is shown) are coupled between the MFCs 181a to 181d and the mass flow meter 186. The mass flow meter 186 is coupled to the one or more shunt lines 184 via the storage tank 185. A plurality of valves 187a to 187d are arranged along the one or more shunt lines 184 (one is shown, but each of the valves 187a to 187d has a dedicated shunt line contemplated) and are coupled between the MFCs 181a to 181d and the supply lines 183a to 183d. The valves 187a to 187d can be three-way and / or four-way valves (a three-way valve is shown). The valves 187a to 187d are operable between a first position, a second position, and a third position. In the first position, each of the valves 187a to 187d allows gas to flow from the respective MFCs 181a to 181d to the processing chamber 100. In the second position, each of the valves 187a to 187d allows gas to flow from the respective MFCs 181a to 181d to the storage tank 185. In the third position, each of the valves 187a to 187d blocks gas from flowing to either the storage tank 185 or the processing chamber 100.

[0023]

[0027] MFCs 181a - 181d supply process gases (deposition gases, injection gases, oxidation gases, etching gases, and / or dopant gases) and purge gases to the processing chamber 100. MFCs 181a - 181d also control the flow rates of such gases. For example, MFCs 181a - 181d supply and control the flow rates of gases that may include one or more of nitrogen (N₂), hydrogen (H₂), hydrogen chloride (HCl), dichlorosilane (DCS), silane (SiH₄), methylsilane (CH₃ - SiH₃), phosphine (PH₃), and / or diborane (B₂H₆). The present disclosure contemplates that other gases may be used.

[0024]

[0028] As an example, the process gas is supplied from MFC 181a and introduced into the processing space 156 through a first gas inlet 174 formed within the sidewall of the base ring 136. The first gas inlet 174 is configured to generally direct the process gas radially inward. During the epitaxial film formation process, the substrate support 106 may be positioned at a processing location adjacent to and substantially at the same height as the first gas inlet 174, facilitating the process gas to flow upward along the flow path 173 in a laminar flow across the upper surface of the substrate 125. The process gas exits the processing space 156 (along the flow path 175) through a gas outlet 178 positioned at a side portion of the processing chamber 100 opposite the first gas inlet 174. The removal of the process gas through the gas outlet 178 may be facilitated by a vacuum pump 180 coupled to the gas outlet 178. Since the first gas inlet 174 and the gas outlet 178 are aligned with each other and arranged at substantially the same height, such a parallel arrangement is believed to enable a generally planar and uniform gas flow across the substrate 125 when combined with the upper dome 128. Further, radial uniformity may be provided by the rotation of the substrate 125 through the substrate support 106.

[0025]

[0029] In another embodiment, the purge gas may be supplied from the second MFC 181b to the purge gas space 158 through an optional second gas inlet 164 formed in the side wall of the base ring 136 (or through the first gas inlet 174). The second gas inlet 164 is located at a lower height than the first gas inlet 174. If a circular shield 167 or a preheating ring is used, the circular shield or preheating ring may be positioned between the first gas inlet 174 and the second gas inlet 164. In either case, the second gas inlet 164 is configured to guide the purge gas generally radially inward. During the epitaxial film formation process, the substrate support 106 may be positioned such that the purge gas circulates laminarly down along the channel 165 across the back side 104 of the substrate support 106. While not constrained by any particular theory, the flow of purge gas is thought to facilitate preventing or substantially avoiding the process gas flow from entering the purge gas space 158, or to reduce the diffusion of process gas into the purge gas region 158 (e.g., the region beneath the substrate support 106). The purge gas exits the purge gas space 158 (along the flow path 166) and is exhausted outside the processing chamber 100 through the gas outlet 178. The gas outlet 178 is located on the side of the processing chamber 100 opposite the second gas inlet 164.

[0026]

[0030] Other MFCs in the gas circuit 180 (such as a third MFC 181c or a fourth MFC 181d) may be configured to introduce gas through the same first inlet 174 and / or the same second inlet 164, or they may be configured to introduce gas through other gas inlets (a third gas inlet and / or a fourth gas inlet).

[0027]

[0031] Although the processing chamber 100 is illustrated and described as an epitaxial deposition chamber, several aspects of the present disclosure may be used in relation to chemical vapor deposition (CVD) chambers, atomic layer deposition (ALD) chambers, physical vapor deposition (PVD) chambers, etching chambers, ion implantation chambers, oxidation chambers, and / or other processing chambers.

[0028]

[0032] The substrate processing system 101 includes a controller 190 coupled to the gas circuit 180. The controller 190 includes a central processing unit (CPU) 191, a memory 192 containing instruction commands, and a support circuit 193 for the CPU 191. The controller 190 either directly controls the MFCs 181a to 181d of the gas circuit 180, or controls them via another computer and / or controller. The controller 190 takes any form of a general-purpose computer processor, or its subprocessors, used in industrial settings to control various chambers and equipment.

[0029]

[0033] Memory 192 or non-temporary computer-readable media is one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, flash drive, or any other form of local or remote digital storage. Support circuitry 193 is coupled to the CPU 191 (processor) to support the CPU 191. Support circuitry 193 includes cache, power supply, clock circuitry, input / output circuitry, and subsystems. Board processing parameters (such as process recipes) and operations are stored in memory 192 as software routines. The software routines are executed or activated to make the controller 190 a dedicated controller for controlling the operation of system 101, such as the gas circuit 180 and the processing chamber 100. The controller 190 is configured to perform any of the methods described herein. When instructions stored in memory 192 are executed, they cause one or more of the operations 302 to 324 of method 300 to be performed.

[0030]

[0034] The various operations described herein (such as operations 302-324 of method 300) can be performed automatically using the controller 190, or they can be performed automatically or manually by specific operations performed by the user.

[0031]

[0035] The controller 190 is configured to perform calibration operations on the MFCs 181a to 181d. The controller 190 prioritizes the multiple MFCs 181a to 181d for calibration operations. Calibration operations on the MFCs 181a to 181d are performed on one MFC at a time during the idle time of the processing chamber 100. Idle time is the time when the substrate 125 is outside the processing space 156 of the processing chamber 100, for example, before the substrate 125 is transferred into the processing chamber 100 or after the substrate 125 is removed from the processing chamber 100. During the calibration operation, the controller 190 sets the MFCs 181a to 181d to flow mode and flows gas through the MFCs 181a to 181d at a target flow rate. The controller 190 instructs the corresponding valves 187a to 187d to direct the gas to the storage tank 185 and the mass flow meter 186. The controller 190 instructs the MFCs 181a to 181d to change the target gas flow rate one by one to a set of flow rates corresponding to a set of set points. The set of flow rates corresponding to a set point may include the minimum and maximum flow rates for the entire operating range of each MFC 181a to 181d. The set of flow rates corresponding to a set point may include the minimum and maximum flow rates for the flow recipe. The change to the flow rate one by one may be performed in a decreasing sequential sequence, an increasing sequential sequence, and / or a random sequential sequence. The controller 190 instructs the mass flowmeter 186 to verify the measured flow rate of gas diverted to the storage tank 185 at each of the set points. The disclosure considers that the storage tank 185 may be omitted and that the mass flowmeter 186 may be directly coupled to one or more diversion lines 184. In such one embodiment, the mass flowmeter 186 verifies the measured flow rate of gas diverted into one or more diversion lines 184 at each of the set points.

[0032]

[0036] By varying the flow rate one by one through multiple flow rates corresponding to multiple setpoints to reach the target flow rate, it becomes easier to verify multiple flow rates that can be used in a process recipe. The mass flowmeter 186 transmits the measured flow rate for each of the multiple setpoints to the controller 190. For each of the multiple setpoints, the controller 190 uses the measured flow rate to determine the flow rate ratio of the measured flow rate to the target flow rate and identifies a corrected flow rate that modifies the measured flow rate to be substantially equal to the target flow rate. The controller 190 identifies the corrected flow rate for each setpoint by dividing the target flow rate by the correction factor. The controller 190 generates a corrected flow rate curve that includes the corrected flow rates across the multiple setpoints. Using the corrected flow rate curve, the corrected flow rate can be identified (estimated) at any point along the corrected flow rate curve, for example, at any point along the entire operating range of each MFC 181a to 181d. In one embodiment, a second corrected flow rate corresponding to a second setpoint can be identified. The second modified flow rate corresponding to the second setpoint is positioned along the modified flow rate curve and, unlike the multiple setpoints, i.e., the second setpoint was not used as one of the multiple setpoints for verification. In one embodiment, which can be combined with multiple other embodiments, the second setpoint lies between two of the multiple setpoints. In one embodiment, which can be combined with multiple other embodiments, the second setpoint lies outside of the multiple setpoints.

[0033]

[0037] Subsequent calibration may result in a second modified flow curve for (one or more) the same setpoints included in the modified flow curve and / or (one or more) different setpoints that are different from the setpoints included in the modified flow curve. In one embodiment, which may be combined with several other embodiments, (one or more) different setpoints were not used during verification for generating the modified flow curve. The second modified flow curve, containing the modified flow rates corresponding to (one or more) the same setpoints and / or (one or more) different setpoints, is integrated with the modified flow curve to generate a new flow curve.

[0034]

[0038] The controller 190 can compare the modified flow rates across multiple setpoints with existing flow rate data collected by the controller 190 during previous iterations of the calibration operation for each of the MFCs 181a to 181d.

[0035]

[0039] The controller 190 may output and display the following on a display (such as a user interface) in the form of graphs and / or tables: multiple setpoints, target flow rates across multiple setpoints, measured flow rates across multiple setpoints, flow rate ratios across multiple setpoints, and / or modified flow rates across multiple setpoints.

[0036]

[0040] The instructions stored in the memory 192 of the controller 190 may include one or more machine learning / artificial intelligence algorithms that can be executed in addition to the operations described herein. In one embodiment, the machine learning / artificial intelligence algorithm executed by the controller 190 prioritizes the MFCs 181a to 181d to perform calibration operations. The controller 190 monitors and stores operating parameters such as operating time for each MFC 181a to 181d and may rank the multiple MFCs 181a to 181d in a rank list according to the operating time for each MFC. The rank list may be continuously monitored and updated using the machine learning / artificial intelligence algorithm. The machine learning / artificial intelligence algorithm may consider previous operating parameters, such as flow rate changes and / or malfunctions for the MFCs 181a to 181d, in order to monitor and update the rank list. In another embodiment, the machine learning / artificial intelligence algorithm executed by the controller 190 may select multiple setpoints and termination flow rates according to data recorded during previous processing operations using a process recipe and / or a process recipe or a different process recipe. The machine learning / artificial intelligence algorithm of the controller 190 further monitors and stores process recipes previously used in the processing chamber 100, and the stored process recipes can be used by the machine learning / artificial intelligence algorithm to select multiple setpoints and termination flow rates.

[0037]

[0041] A machine learning / artificial intelligence algorithm can prioritize multiple setpoints used in the calibration operation (corresponding to the flow rates used in the process recipe) according to a second ranking list that ranks the multiple setpoints.

[0038]

[0042] Figure 2 is a schematic cross-sectional view of a mass flow controller (MFC) 200 according to one embodiment. The MFC 200 can be used as one of the MFCs 181a to 181d shown in Figure 1. The MFC 200 receives gas from a gas source through an inlet 207. The gas received through the inlet 207 encounters a flow limiting device 211 located in a bypass 220. A sensor device 204 is configured to measure the flow rate of gas passing through the MFC 200. After the gas has passed through the sensor device 204 and / or the limiting device 211, the gas then encounters a flow control valve 206. After passing through the flow control valve 206, the gas flows through an outlet 221 to one of the valves 187a to 187d. The flow control valve 206 includes a piezo actuator 227 and a metal diaphragm 228.

[0039]

[0043] The MFC200 is coupled to the controller 190. The MFC200 receives a flow input signal 223 (including, for example, a target flow rate during calibration) from the controller 190 and transmits a flow output signal 224 to the controller 190. The flow output signal 224 may be measured using a sensor device 204. The measured flow rate, confirmed over multiple setpoints using a mass flow meter 186, is distinct from the flow output signal 224 measured using the sensor device 204. The MFC200 receives power supply 225 from a power source.

[0040]

[0044] Due to drift or shift-on-zero, the measured flow rate, for example, confirmed using the mass flow meter 186, may be more accurate for operational processing purposes than the flow output signal 224.

[0041]

[0045] The MFC200 includes module 230. Module 230 includes an A / D converter 231 coupled to a sensor device 204, a valve drive circuit 232 coupled to a flow control valve 206, and a CPU 233. Module 230 also includes a driver / receiver 234 and a D / A to A / D converter 235.

[0042]

[0046] Figure 3A is a schematic block diagram of a method 300 for performing a calibration operation on multiple mass flow controllers (MFCs) of a substrate processing system according to one embodiment. Operation 302 of method 300 includes prioritizing the multiple MFCs for calibration. Prioritizing operation 302 includes identifying the operating time of each of the multiple MFCs and ranking the multiple MFCs in a rank list according to the operating time of each MFC. The operating time of each MFC is the total time that each MFC has been set to flow mode since the previous calibration of that MFC. The operating times of each of the multiple MFCs are ranked in the rank list from the maximum operating time to the minimum operating time.

[0043]

[0047] This disclosure takes into consideration that users may manually select a subset of multiple MFCs for calibration operations.

[0044]

[0048] Operation 304 of Method 300 includes performing calibration operations on multiple MFCs during idle time in the substrate processing system, according to a rank list. Idle time is the time when the substrate is outside the processing space of the processing chamber of the substrate processing system. The calibration operations are performed according to a rank list. Thereafter, the calibration operation is performed on the first MFC corresponding to the maximum operating time, before the other MFCs of the multiple MFCs. After the calibration operation on the first MFC has been performed, the calibration operation is performed on one or more of the other MFCs during idle time or during one or more further idle times. Performing calibration operations on multiple MFCs is preferred and coordinated over multiple idle times, and the multiple idle times may be separated by different stages of substrate processing operation and / or different substrates on which the substrate processing operation is performed.

[0045]

[0049] The calibration operation of operation 304 may be performed (e.g., triggered) at an operation interval. In one embodiment, which may be combined with several other embodiments, the operation interval is a board interval, such as every 1000 boards processed. In one embodiment, which may be combined with several other embodiments, the operation interval is an idle time interval, such as an event where the idle time exceeds 30 minutes. The calibration operation may also be performed (e.g., triggered) by analyzing the existing corrected flow (from a previous iteration of the calibration operation) for each MFC and predicting the drift of each MFC. The analysis and prediction may be performed by a machine learning / artificial intelligence algorithm of the controller 190.

[0046]

[0050] Figure 3B is a schematic block diagram of performing the calibration operation 304 shown in Figure 3A according to one embodiment. The calibration operation is first performed on the first MFC in the rank list. Calibration operations 312-324 may be repeated one at a time for each of the multiple MFCs in the order of the rank list during one or more idle times of the machine.

[0047]

[0051] Operation 312 includes setting the first MFC of a plurality of MFCs to flow mode and flowing gas through the first MFC at a target flow rate.

[0048]

[0052] Operation 314 includes directing the gas to a mass flow meter. Operation 316 includes changing the target flow rate of the gas one by one to a plurality of flow rates corresponding to a plurality of setpoints. The plurality of flow rates corresponding to a plurality of setpoints may include the minimum and maximum flow rates over the entire operating range of the first MFC. The plurality of flow rates corresponding to a plurality of setpoints may include the minimum and maximum flow rates of a flow recipe. The plurality of flow rates may be stepped through in decreasing sequential sequences, increasing sequential sequences, and / or random sequential sequences.

[0049]

[0053] Operation 318 includes using a mass flow meter to verify the measured flow rate of gas at each of several setpoints. The end flow rate and the setpoints may be selected by the user or by a controller (e.g., controller 190). In one embodiment, which may be combined with several other embodiments, the setpoints and end flow rates correspond to several stages of a process recipe used for each first MFC during a processing operation (e.g., an epitaxial deposition operation) (e.g., selected accordingly). In one embodiment, which may be combined with several other embodiments, operation 302 includes prioritizing several setpoints (corresponding to the flow rates used in the process recipe) for each MFC used in a calibration operation. The setpoints are prioritized according to a second rank list that ranks the setpoints. The second rank list may rank the setpoints based on how often and / or how recently they have been used.

[0050]

[0054] Operation 320 includes identifying the flow rate ratio between the measured flow rate and the target flow rate for each of a plurality of setpoints. Operation 322 includes identifying a corrected flow rate for each of a plurality of setpoints that modifies the measured flow rate to be substantially equal to the target flow rate. If drift occurs in the first MFC, the corrected flow rate corrects the drift by modifying the actual flow rate (measured flow rate) to be substantially equal to the target flow rate. The flow rate ratio for each setpoint is identified by dividing the measured flow rate by the target flow rate. The corrected flow rate for each setpoint is identified by dividing the target flow rate by the correction factor. In one embodiment, which may be combined with several other embodiments, the correction factor is equal to the flow rate ratio. The correction factor for each setpoint may be plotted on a multipoint curve. In one embodiment, which may be combined with several other embodiments, the correction factor is the average of the flow rate ratio and one or more existing ratios calculated in one or more previous iterations of the calibration operation of the first MFC.

[0051]

[0055] If a specified flow ratio (one or more) is outside the first tolerance range or within a second tolerance range narrower than the first tolerance range, it may be ignored (e.g., excluded from correction factor identification) and deleted, and / or correction factors equal to those flow ratios may be ignored and deleted (e.g., not used during operation of the first MFC). A flow ratio (one or more) and / or correction factor is acceptable if it is within the first tolerance range and outside the second tolerance range. In one embodiment, which may be combined with several other embodiments, the first tolerance range is 0.7 to 1.3. In one embodiment, which may be combined with several other embodiments, the second tolerance range is 0.995 to 1.005. Other first and second tolerance ranges are also considered. The first and second tolerance ranges may be set by the user and / or determined by, for example, a machine learning / artificial intelligence algorithm. The first and second tolerances may be determined by performing a historical deviation operation on existing flow ratio data and / or existing correction coefficient data from previous iterations of the calibration operation. If a flow ratio (one or more) is outside the first tolerance or within the second tolerance, an alarm may be generated and the alarm may be sent to the user, such as by sending the alarm to a display. The alarm may indicate that a particular flow ratio (one or more) is outside the first tolerance or within the second tolerance.

[0052]

[0056] Operation 324 includes generating a graph with a modified flow curve. Generating the graph includes plotting the modified flow for each of a setpoint in a plurality of setpoints within the graph. Generating the graph also includes connecting the modified flow for each of the setpoints in the plurality of setpoints within the graph using smooth curve fitting to generate a modified flow curve for the first MFC. The graph may also include existing flow curves for the first MFC generated from previous iterations of the calibration operation. The modified flow curve is compared with the existing flow curve, and either may be accepted or rejected. If accepted, the modified flow curve is merged with the existing flow curve by weighting and averaging the modified flow curve and the existing flow curve to generate a new flow curve.

[0053]

[0057] Weighting and averaging of modified flow curves and existing flow curves involves assigning weights to the modified flow of the modified flow curve and the existing flow of the existing flow curve before averaging. The assigned weights may take into account the duration age of the existing flow and the ratio of the modified flow to the existing flow at each setpoint. This disclosure takes into account that the modified flow of each MFC may be ignored (e.g., excluded from averaging) and removed if it is outside a first tolerance range of 0.7 to 1.3 or within a second tolerance range of 0.995 to 1.005. The modified flow is acceptable if its ratio is within the first tolerance range and outside the second tolerance range. Other first and second tolerance ranges are also taken into consideration. The first and second tolerance ranges may be set by the user and / or determined by, for example, a machine learning / artificial intelligence algorithm. The first and second tolerance ranges may be determined by performing a historical deviation operation on existing ratio data from previous iterations of the calibration operation. If the ratio falls outside the first acceptable range or within the second acceptable range, an alarm is generated and the alarm may be sent to the user, for example, by sending the alarm to the display. The alarm may indicate that the ratio falls outside the first acceptable range or within the second acceptable range. The user may choose whether to delete the ratio that falls outside the first acceptable range or within the second acceptable range.

[0054]

[0058] In one embodiment, which may be combined with several other embodiments, the modified flow curve (if permitted) is integrated with a global correction factor across multiple setpoints by weighting and averaging the correction factor at each setpoint with the global correction factor. The global correction factor may be identified using a previous single-setpoint calibration operation similar to the calibration operation of operation 304.

[0055]

[0059] If accepted, the new flow curve may be used to operate each MFC. If the modified flow curve differs from the existing flow curve, the modified flow curve may be rejected. If the modified flow curve is rejected, the existing flow curve may be used to operate each MFC. If the modified flow curve is accepted and no existing flow curve exists, the modified flow curve may be used to operate each MFC.

[0056]

[0060] The modified flow curve, the existing low curve, and / or the new flow curve may be output and displayed on a display (such as a user interface) in the form of a graph and / or table.

[0057]

[0061] Referring to Figure 3A, operation 306 of method 300 includes operating one or more of a plurality of MFCs (e.g., a first MFC) during a substrate processing operation (e.g., an epitaxial deposition operation). Each MFC to be operated operates according to a new flow curve (if selected), a modified flow curve (if selected), an existing flow curve (if selected), or a global correction factor (if selected). One or more of the plurality of MFCs are operated while the substrate processing operation is performed at a temperature in the range of 200 to 800 degrees Celsius. Each MFC operates across the operating setpoint using a modified flow rate corresponding to the operating setpoint. The modified flow rate is positioned along one of the curves (depending on which curve is selected). The modified flow rate can be specified at any point along the modified flow rate curve, such as any point along the entire operating range of each MFC. In one embodiment, a second modified flow rate corresponding to a second setpoint may be specified. The second setpoint may be one of the operating setpoints. The second modified flow rate corresponding to the second setpoint is positioned along the modified flow rate curve and, unlike the multiple setpoints, i.e., the second setpoint was not used as one of the multiple setpoints for verification. In one embodiment, which can be combined with multiple other embodiments, the second setpoint lies between two of the multiple setpoints. In one embodiment, which can be combined with multiple other embodiments, the second setpoint lies outside of the multiple setpoints.

[0058]

[0062] This disclosure takes into account that, without having yet implemented the modified flow curves and / or new flow curves in the operation of each MFC during the board processing operation, the modified flow curves (with modified flow) and / or new flow curves (with new flow) may be generated in data acquisition mode and stored in memory.

[0059]

[0063] Figure 4 is a schematic diagram of graph 400 according to one embodiment. The X-axis of graph 400 includes the target flow rate (in standard cubic centimeters per minute (SCCM)), and the Y-axis of graph 400 includes the modified flow rate (in SCCM). The existing flow curve 410 and the modified flow curve 430 are plotted in graph 400. The existing flow curve 410 includes multiple setpoints 411a to 411d, and using smooth curve fitting, a curved fitting line 412 extends through the setpoints 411a to 411d. The modified flow curve 430 includes multiple setpoints 431a to 431k, and using smooth curve fitting, a curved fitting line 432 extends through the setpoints 431a to 431k.

[0060]

[0064] This disclosure considers that integrating a modified flow curve 430 with an existing flow curve 410 by weighting and averaging (as described with respect to operation 324 of method 300) may include integrating a specific setpoint at a particular target flow rate with a point along one of the curved fitting lines 412, 432 positioned at a particular target flow rate. In one embodiment, the existing flow rate at setpoint 411b may be weighted and averaged with a modified flow rate positioned along a curved fitting line 432 perpendicular to setpoint 411b and along a vertical axis 450 positioned at the target flow rate of setpoint 411b. The existing flow rate at setpoint 411b can be weighted and averaged with the modified flow rate positioned along the curved fitting line 432 to calculate a new modified flow rate at setpoint 411b.

[0061]

[0065] The various advantages of this disclosure include automatic correction of the mass flow controller (MFC), accurate correction of the MFC across the operating flow rate range, reduced possibility of over- and under-correction, modularization of applicability to various MFCs, reduced cost and labor expenditure, reduced machine downtime, reduced operational delay, accurate and enhanced uniformity of deposition, and improved throughput.

[0062]

[0066] As one embodiment, calibrating MFCs one by one during idle time and prioritizing multiple MFCs for calibration operations can reduce machine downtime and improve throughput. As another embodiment, integrating a modified flow curve (with modified flow rates) with an existing flow curve (with existing flow rates) facilitates accurate calibration and correction of MFCs. Such multiple embodiments are expected to yield unexpected results in terms of improved efficiency, increased throughput, and reduced machine downtime.

[0063]

[0067] It is conceivable that one or more embodiments disclosed herein may be combined. For example, one or more embodiments, features, components, and / or characteristics of the substrate processing system 101, MFC 200, method 300, operation 304, and / or graph 400 may be combined. Furthermore, it is considered that one or more embodiments disclosed herein may include some or all of the aforementioned advantages.

[0064]

[0068] The foregoing covers a number of embodiments of the present disclosure, but other embodiments and further embodiments of the present disclosure may be devised without departing from the basic scope of the present disclosure. The present disclosure also takes into consideration that one or more aspects of the embodiments described herein may be replaced by one or more of the other aspects described. The scope of the present disclosure is defined by the following claims.

Claims

1. A method for performing calibration operations on multiple mass flow controllers in a substrate processing system, A prioritized rank list of the plurality of mass flow controllers, wherein a first mass flow controller is selected from the plurality of mass flow controllers according to the rank list prioritized according to the operating time of each mass flow controller. The first mass flow controller described above is The gas is flowed at a target flow rate through the first mass flow controller. The target flow rate of the gas is changed one by one to a plurality of flow rates corresponding to a plurality of set points. A mass flow meter is used to confirm the measured flow rate of the gas at each of the multiple set points. Calibration is performed by Methods that include...

2. The method according to claim 1, further comprising updating the prioritized rank list in taking into account a change in flow rate or malfunction of one of the plurality of mass flow controllers.

3. The method according to claim 1, further comprising selecting the plurality of setting points according to a process recipe.

4. The method according to claim 3, wherein the plurality of setting points are selected based on data recorded during the processing operation including the process recipe.

5. The method according to claim 3, wherein each of the plurality of setting points corresponds to the flow rate of the gas in the process recipe.

6. Further includes generating an additional prioritized rank list of the aforementioned multiple setting points, The method according to claim 5, wherein the target flow rate is changed one by one to the plurality of flow rates according to the additional prioritized rank list.

7. A method for performing calibration operations on a plurality of mass flow controllers of a substrate processing system, Selecting a first mass flow controller from the plurality of mass flow controllers according to a prioritized rank list of the plurality of mass flow controllers, The first mass flow controller described above is The gas is flowed at a target flow rate through the first mass flow controller. The target flow rate of the gas is changed one by one to a plurality of flow rates corresponding to a plurality of setpoints, according to an additional prioritized rank list of a plurality of setpoints selected to correspond to the flow rate of the gas in the process recipe, A mass flow meter is used to confirm the measured flow rate of the gas at each of the multiple set points. Calibration is performed by Methods that include...

8. Selecting a second mass flow controller from among the multiple mass flow controllers according to the aforementioned prioritized ranking list, Calibrating the second mass flow controller and The method according to claim 1, further comprising:

9. A method for performing calibration operations on multiple mass flow controllers in a substrate processing system, A prioritized rank list of the plurality of mass flow controllers, wherein a first mass flow controller is selected from the plurality of mass flow controllers according to the rank list prioritized according to the operating time of each mass flow controller. The first mass flow controller described above is The gas is flowed at a target flow rate through the first mass flow controller. The target flow rate of the gas is changed one by one to a plurality of flow rates corresponding to a plurality of set points. Using a mass flow meter, the measured flow rate of the gas at each of the multiple set points is confirmed. Regarding each setting point, Identify the flow rate ratio of the measured flow rate to the target flow rate, Correct the measured flow rate and identify the corrected flow rate. Calibration is performed by Methods that include...

10. Using the modified flow rates for each setpoint, predict the drift of the first mass flow controller, Based on the drift, the repetition of the calibration of the first mass flow controller is initiated. The method according to claim 9, further comprising:

11. A method for performing calibration operations on multiple mass flow controllers in a substrate processing system, Monitoring the operating parameters of each of the aforementioned multiple mass flow controllers, A prioritized rank list of the multiple mass flow controllers is generated according to the aforementioned operating parameters, Selecting a first mass flow controller from the plurality of mass flow controllers according to the prioritized rank list of the plurality of mass flow controllers, The first mass flow controller described above is The gas is flowed at a target flow rate through the first mass flow controller. The target flow rate of the gas is changed one by one to a plurality of flow rates corresponding to a plurality of set points. A mass flow meter is used to confirm the measured flow rate of the gas at each of the multiple set points. Calibration is performed by Methods that include...

12. The method according to claim 11, further comprising performing the calibration of the first mass flow controller during the idle time of the substrate processing system.

13. The method according to claim 11, further comprising updating the prioritized rank list in consideration of a change in flow rate or malfunction of one of the plurality of mass flow controllers.

14. For each of the aforementioned multiple setting points, To identify the flow rate ratio of the measured flow rate to the target flow rate, Correcting the measured flow rate, identifying the corrected flow rate, and The method according to claim 11, further comprising:

15. For each of the aforementioned multiple setting points, The modified flow rate is determined by dividing the target flow rate by the modification factor. The aforementioned correction factor is, The aforementioned flow rate ratio, or The average of the flow rate ratio and one or more previous flow rate ratios obtained as a result of one or more previous calibration operations of the first mass flow controller. The method according to claim 14, which is equivalent to one of the following.

16. For each of the aforementioned multiple setting points, The flow rate ratio is compared with a first permissible range and a narrower second permissible range. In accordance with the above comparison, the flow rate ratio may be accepted or rejected. The method according to claim 14, further comprising:

17. The method according to claim 16, further comprising specifying the first tolerance range and the second tolerance range for each of the plurality of setting points based on a previous flow ratio or correction coefficient obtained as a result of one or more previous calibration operations of the first mass flow controller.

18. For each of the aforementioned multiple setting points, the corrected flow rate is plotted in the graph. Using smooth curve fitting, connect the modified flow rates for each of the multiple setpoints in the graph to generate a first modified flow curve for the first mass flow controller. The method according to claim 14, further comprising:

19. With respect to the first mass flow controller, the first modified flow curve is compared with a second modified flow curve obtained as a result of a previous calibration of the first mass flow controller. A third modified flow curve is generated by weighting and averaging the first modified flow curve and the second modified flow curve. The method according to claim 18, further comprising:

20. The method according to claim 18, further comprising adjusting the first modified flow curve using a global correction factor to generate a second modified flow curve.

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