Liquid level sensor system and false alarm prevention system

Abstract

The disclosure describes a liquid level sensor system and a false alarm prevention system configured as a low water level alarm system for preventing errors in a semiconductor processing system. The system includes a reservoir configured to contain a liquid and a sensor system configured to delay an alarm for a predetermined duration. In some embodiments, the sensor system includes a sensor configured to determine a fluid level in the reservoir and send a signal indicative of the fluid level to the alarm system, and a delay circuit coupled to the fluid level sensor and configured to delay issuing of the signal to the alarm system for a predetermined duration.

Description

Technical Field

[0001] This disclosure relates to a liquid level sensing system and a false alarm prevention system. Background Technology

[0002] In semiconductor manufacturing processes that require water, sudden changes in water levels can cause equipment malfunctions. Equipment malfunctions can result in significant losses of products and production (e.g., the time spent repairing and replacing defective equipment). Consequently, the cost of the semiconductor manufacturing process increases. Utility Model Content

[0003] According to some embodiments of this disclosure, a false alarm prevention system includes a reservoir and a level sensor system. The reservoir is configured to contain liquid. The sensor system is configured to delay an alarm system for a predetermined duration. The sensor system includes a first level sensor and a first delay circuit. The first level sensor is located at a predetermined liquid level in the reservoir and configured to determine the liquid level in the reservoir and transmit a first signal indicating the liquid level to the alarm system. The first delay circuit is communicatively coupled to the first level sensor and configured to delay the first signal sent to the alarm system for a predetermined duration.

[0004] According to some embodiments of this disclosure, a liquid level sensing system includes a first liquid level sensor, a first delay circuit, a second liquid level sensor, and a second delay circuit. The first liquid level sensor is located at a predetermined liquid level in a storage tank and configured to determine the liquid level in the storage tank and transmit a first signal indicating the liquid level to an alarm system. The first delay circuit is communicatively coupled to the first liquid level sensor and configured to delay the transmission of a first signal to the alarm system for a predetermined duration, wherein the first signal is a first low liquid level event signal. The second liquid level sensor is substantially flush with the first liquid level sensor. The second delay circuit is communicatively coupled to the second liquid level sensor and configured to delay the transmission of a second signal from the second liquid level sensor to the alarm system, wherein the second signal is a second low liquid level event signal, and wherein the first liquid level sensor and the first delay circuit, as well as the second liquid level sensor and the second delay circuit, constitute a redundant sensing system.

[0005] According to some embodiments of this disclosure, a false alarm prevention system includes a reservoir and a level sensor system. The reservoir is configured to contain liquid. The sensor system is configured to delay an alarm system for a predetermined duration. The level sensor system includes a first level sensor, a first delay circuit, a second level sensor, and a second delay circuit. The first level sensor is located at a predetermined level in the reservoir and configured to determine the level in the reservoir and transmit a first signal indicating the level to the alarm system. The first delay circuit is communicatively coupled to the first level sensor and configured to delay the first signal sent to the alarm system for a predetermined duration, wherein the first signal is a first low level event signal. The second level sensor is substantially flush with the first level sensor. The second delay circuit is communicatively coupled to the second level sensor and configured to delay the transmission of a second signal from the second level sensor to the alarm system, wherein the second signal is a second low level event signal, wherein the first level sensor and the first delay circuit, as well as the second level sensor and the second delay circuit, comprise a redundant sensor system. Attached Figure Description

[0006] The nature of this disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. Please note that, in accordance with industry standard practices, the various features are not drawn to scale. In fact, for clarity of explanation, the dimensions of the various features may be arbitrarily increased or decreased.

[0007] Figure 1 This is a flowchart of a semiconductor process utilizing stored water according to some embodiments;

[0008] Figure 2 This is a block diagram of a water supply system according to some embodiments;

[0009] Figure 3A and Figure 3B This is a diagram illustrating the sensor positions according to some embodiments;

[0010] Figure 4A , Figure 4B , Figure 4C and Figure 4D It is a diagram showing the water level changes in a storage tank according to some embodiments;

[0011] Figure 5A and Figure 5B A faulty low water level alarm prevention system according to some embodiments is described;

[0012] Figure 6A , Figure 6B and Figure 6C It is a graphical depiction of signal delay according to some embodiments;

[0013] Figure 7This is a flowchart of a method for employing a false alarm prevention system according to some embodiments.

[0014] [Symbol Explanation]

[0015] 100: Process

[0016] 105: Base Coating Operation

[0017] 110: Cooling Operation

[0018] 115: Operation

[0019] 120: Operation

[0020] 125: Operation

[0021] 200: Water supply system

[0022] 205: Water Source

[0023] 210: Humidifier System

[0024] 220: Freezer Unit

[0025] 230: Humidifier Unit

[0026] 235: Blower

[0027] 240: Cooling water system

[0028] 245: Semiconductor Processing Tools

[0029] 250: slot

[0030] 255: Pump

[0031] 260: Cooling unit

[0032] 270: Heating coil

[0033] 275: Alarm System

[0034] 310: Liquid level sensor

[0035] 320: Heating coil

[0036] 330: Liquid level sensor

[0037] 410: Horizontal dashed line

[0038] 420: Wavy dotted line

[0039] 430: Horizontal dashed line

[0040] 440: Wavy dotted line

[0041] 500: False Alarm Prevention System

[0042] 501: False Alarm Prevention System

[0043] 510: Delay circuit

[0044] 520: Switch

[0045] 530: Delay Circuit

[0046] 540: Switch

[0047] 610: Drawing lines

[0048] 615: Sensing Interval

[0049] 617: Rest Interval

[0050] 618: Sensing Interval

[0051] 620: Drawing lines

[0052] 630: Drawing lines

[0053] 635: Delayed sensing interval

[0054] 640: Drawing lines

[0055] 645: Maximum Delay Sensing Time

[0056] 650: Drawing lines

[0057] 660: Drawing lines

[0058] 655: Sensing Interval

[0059] 665: points

[0060] 670: Sensing Interval

[0061] 700: Method

[0062] 710: Operation

[0063] 720: Operation

[0064] 730: Operation

[0065] 740: Operation

[0066] 750: Operation

[0067] 760: Operation

[0068] 770: Operation Detailed Implementation

[0069] The following disclosure provides numerous different embodiments or instances for implementing various features of the provided object. Specific examples of components and configurations will be described below to simplify this disclosure. Of course, these are merely examples and are not intended to be limiting. For example, the scenario described below, where a first feature is formed on or above a second feature, may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features may be formed between the first and second features such that the first and second features are not in direct contact. Furthermore, reference numerals and / or letters may be repeated throughout this disclosure. This repetition is for simplicity and clarity and does not in itself establish a relationship between the various embodiments and / or configurations discussed.

[0070] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of this disclosure and in particular. Certain terms used to describe this disclosure will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing this disclosure.

[0071] Furthermore, for the convenience of describing the relationship between one element or feature as illustrated in the figures and other elements or features(s), spatially related terms such as “below,” “under,” “lower,” “above,” “upper,” “top,” “bottom,” and similar terms are used herein. Spatially related terms are intended to cover different orientations of the device during use or operation, other than those depicted in the figures. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially related descriptors used herein can be interpreted similarly.

[0072] As used herein, “approximately,” “about,” “approximately,” or “substantially” should generally refer to any approximation of a given value or range, wherein the approximation varies depending on the various fields to which it pertains, and the scope of the approximation should conform to the broadest interpretation understood by one skilled in the art in which the approximation is described, so as to encompass all such modifications and similar structures. In some embodiments, an approximation should generally mean within 20%, preferably 10%, and more preferably 5% of a given value or range. The numerical quantities given herein are approximate, which means that the terms “approximately,” “about,” “approximately,” or “substantially” may be inferred or imply other approximations unless explicitly stated otherwise.

[0073] As used in this article, “a,” “an,” and “the” include both singular and plural references, unless the context clearly indicates otherwise.

[0074] When used in a list of two or more items, the term "and / or" means that any of the listed items can be used alone or in combination with any one or more of the listed items. For example, the expression "A and / or B" is intended to mean one or both of A and B, i.e., A alone, B alone, or a combination of A and B. The expression "A, B and / or C" is intended to mean A alone, B alone, C alone, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B and C.

[0075] The embodiments described herein relate to a system configured to prevent false low-level alarms in a system temperature and humidity control (STHC) system. The system includes a reservoir configured to contain liquid and a sensor system configured to delay the alarm for a predetermined duration. In some embodiments, the sensor system includes a sensor configured to determine the fluid level in the reservoir and send a signal indicating the fluid level to the alarm system and a delay circuit. For example, the signal may be a low fluid level event signal. The delay circuit is coupled to the level sensor and configured to delay the signal sent to the alarm system for the predetermined duration.

[0076] In some embodiments, the liquid may be selected from cooling liquids, heat transfer liquids, lubricating liquids, coating liquids, or any liquid suitable for semiconductor processing. For example, the liquid may be water to maintain humidity levels in the semiconductor processing tool, or a cooling liquid to provide processing cooling to the semiconductor processing tool and / or product. In some embodiments disclosed herein, the liquid may be any of water, oil, emulsion, supercooled liquid, or combinations thereof.

[0077] In some embodiments of this disclosure, the fluid level sensor system may be incorporated into a fluid storage tank (e.g., a water tank). In some embodiments of this disclosure, the fluid storage tank is configured to supply water to a cooling water system and / or a humidifier system. In some examples, the cooling water system and / or humidifier system may be fluidly connected to the semiconductor processing tool to maintain processing parameters, such as temperature and humidity.

[0078] In some embodiments of this disclosure, the fluid level sensor system may be configured to initiate a shutdown protocol associated with the processing system if a sudden drop in fluid level (e.g., water level) is detected. In some embodiments of this disclosure, the shutdown protocol is employed to protect the processing system from damage. In some embodiments of this disclosure, if chilled water suddenly stops flowing to the processing system, the processing system, which relies on chilled water for its function, may be damaged. For example, if a certain temperature is not maintained, the cooling components of the processing system may overheat, burn out, or deform.

[0079] In some cases, a drop in water level may be a reaction to the movement of fluid storage tanks due to one of a variety of reasons. For example, fluid storage tanks may move or shake during an earthquake due to operator error and / or severe weather. As a result, shutting down the processing system may be unjustified and cause unnecessary damage to one or more products being processed by the system, as well as to the system itself. Furthermore, unnecessary damage to the processing system may incur additional costs in the form of labor hours spent repairing the system.

[0080] In some embodiments of this disclosure, the processing system may be a semiconductor manufacturing processing system whose operation requires water. For example, the process may require water for cooling and / or for humidity control. In some embodiments of this disclosure, cooling may be directed at the processing system itself, associated tools, or the product being processed by the processing system. For example, a processing system requiring chilled water may be a cryogenic vacuum pump helium compressor. Associated tools may be quartz crystal thin film deposition thickness monitors. In some embodiments of this disclosure, the product is a silicon wafer that requires a cooling operation after a baking operation.

[0081] In some embodiments disclosed herein, certain semiconductor processing tools may be adversely affected by natural phenomena. For example, a power outage caused by a severe storm may shut down all or at least part of a semiconductor manufacturing facility. Floods may have a devastating impact on cleanrooms and the semiconductor processing tools contained therein. Earthquakes may disrupt the operation of semiconductor process tools.

[0082] In some embodiments disclosed herein, even minor earthquakes can damage semiconductor processing tools in semiconductor manufacturing facilities. For example, the mask alignment process may be interrupted by an earthquake, resulting in mask misalignment. Such mask misalignment can be detrimental to any downstream processing. Cleanroom high-efficiency particulate air (HEPA) filters may shift during an earthquake, allowing particulate contaminants to adversely affect the functionality of smaller semiconductor devices.

[0083] Figure 1A flowchart illustrating an exemplary process flow 100 for silicon wafer fabrication preparation according to some embodiments of this disclosure is shown. During a priming operation 105, a priming material such as hexamethyldisilazane (HDMS) is deposited onto the wafer (e.g., by spin-casting). After the spin-casting operation, a cooling operation 110 is performed on the wafer (e.g., by placing the wafer on a cooling plate).

[0084] In some embodiments disclosed herein, the cooling plate may be fluidly connected to a cooling water system. For example, the cooling water system may include supply and return lines (running from a water source and flowing to / from the cooling plate), a reservoir, pumps, cooling units, and various monitoring sensors.

[0085] For example, a cooling water system may include temperature sensors, water flow sensors, and water pressure sensors. Furthermore, the reservoir of the cooling water system may include a level sensor. In some embodiments, the level sensor inside the reservoir may be electrically coupled to an alarm system configured to warn semiconductor processing tool users and / or technicians that the water level has dropped below a threshold level used to protect the liquid reservoir. Semiconductor process tools (e.g., cooling plates) are protected from harmful events. For example, overheating can lead to loss of products being processed by the semiconductor processing tool, damage to the semiconductor processing tool (e.g., burnout, deformation, electronic malfunction, etc.), time required to repair or replace the semiconductor processing tool, and impacts on downstream processing tools. For example, hot wafers (in other words, uncooled wafers) can damage wafer loading stations, wafer unloading stations, robotic wafer handling systems, vacuum chucks (e.g., O-rings located within vacuum chucks used to hold wafers during processing), or any other thermally vulnerable processing and / or wafer processing equipment.

[0086] In some embodiments, at operation 115, the wafer may be coated with a thin film for various reasons. For example, a functional thin film may be coated onto the wafer to create horizontal electrical interconnects. In other instances, a sacrificial thin film may be coated onto the wafer to protect device features from downstream processing. In some embodiments, the coating apparatus may require chilled water from a cooling water system to cool moving parts. In some embodiments, the coating apparatus may require humidity control within the coating chamber to control film deposition. For example, spin-coated films may require higher humidity to form a hydrated thin film, or spin-coated films may require very low humidity for rapid drying.

[0087] In some embodiments, at operation 120, the heating system (e.g., a hot plate, oven, or vacuum oven) may require chilled water from a cooling water system for safe operation. The heating system can use chilled water to maintain a safe temperature for portions of the heating system located outside the heating chamber and / or the heating plate. For example, electronic equipment controlling the heating system can be cooled by the cooling water system to extend the cycle life of the heating system's electronic equipment. Furthermore, chilled water from the cooling water system can be used to control the temperature of the heating chamber and / or the heating plate.

[0088] In some embodiments, at operation 125, a cooling system may be used to cool the wafer after heating operation 120. Cooling lines supplying cooling water from a cooling water system may be used to remove heat from a heat sink supporting the hot wafer. For example, the hot wafer may be placed on an aluminum cooling plate that is fluidly connected to the cooling water lines, allowing the cooling water to absorb and remove the heat from the wafer.

[0089] Now for reference Figure 2 This diagram shows a block diagram of a water supply system 200 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the water supply system 200 may be a system temperature and humidity control (STHC) system. For example, an STHC system may be configured to control temperature or humidity in a semiconductor processing tool, temperature and humidity in a semiconductor processing tool, temperature in a first semiconductor processing tool and humidity in a second semiconductor processing tool, temperature in multiple semiconductor processing tools, humidity in multiple semiconductor process tools, temperature and humidity in multiple semiconductor process tools, or any combination of temperature and / or humidity that needs to be controlled in any exemplary semiconductor process tool.

[0090] Figure 2 The humidifier system 210 and the cooling water system 240 are described. Now turn to... Figure 2 In the illustrated humidifier system 210 example, process water flows into the humidifier system 210 from a water source 205 and enters a refrigeration unit 220. The refrigeration unit 220 can cool the process water to a temperature suitable for storage and processing by the humidifier unit 230. The humidifier unit 230 can be configured to heat and evaporate the process water, and a blower 235 can push the evaporated water into a semiconductor processing tool 245. The semiconductor processing tool 245 can be, for example, a cooling plate, an epitaxial growth furnace, a reactive ion etching tool, an evaporator, a sputtering device, a quartz crystal thin film thickness monitor, a vacuum pump, etc. In some embodiments, the humidifier unit 230 may include various sensors, such as a liquid level sensor. The liquid level sensor in the humidifier unit 230 can be used for a variety of purposes.

[0091] Figure 3A An illustration shows the liquid level sensor 310 placed within the humidifier unit 230. Firstly, in some embodiments disclosed herein, Figure 3A The illustrated level sensor 310 can transmit water level information to a system configured to maintain a predetermined water level in the humidifier unit 230 to ensure sufficient fluid content (e.g., sufficient water content in the humidifier unit 230). In some embodiments disclosed herein, the level sensor 310 may be configured to transmit a low water level notification to an alarm system 275, such as... Figure 2 As shown.

[0092] In some embodiments of this disclosure, alarm system 275 may be configured to shut down semiconductor processing tool 245, which depends on the operation of humidifier system 210. In some embodiments of this disclosure, such shutdown may have adverse effects on semiconductor processing tool 245. For example, products being processed by semiconductor processing tool 245 may need to be scrapped, semiconductor processing tool 245 itself may need maintenance before restarting, and the time of workers and / or technicians may have to be unnecessarily consumed to bring semiconductor processing tool 245 back online.

[0093] In some embodiments, the alarm system 275 can be triggered by receiving two consecutive low fluid level signals (e.g., two low water level signals) from the level sensor 310. For example, the level sensor 310 can send a first low water level signal to the alarm system 275 to initiate the trigger event. After a duration of approximately 4 seconds to approximately 60 seconds, if the level sensor 310 still reads a low water level, the level sensor 310 can send a second consecutive low water level signal to the alarm system 275. In some embodiments, if the alarm system 275 receives the second consecutive low water level signal from the level sensor 310, the alarm system 275 is triggered and the semiconductor processing tool 245 can be shut down. On the other hand, if the alarm system 275 does not receive the second low water level signal from the level sensor 310, the alarm system 275 will not be triggered. Looking ahead, the two consecutive low water level signal transmissions will be referred to as a "low fluid (water) level event signal".

[0094] Return to reference Figure 2 It shows that the water supply system 200 has a cooling water system 240. For example... Figure 2As shown, process water can flow from water source 205 into cooling water system 240 and into tank 250. Tank 250 can contain process water chilled water that can be pumped through cooling unit 260 and through heating coil 270 before being supplied to cooling unit 260 by pump 255. In some embodiments, heating coil 270 can be used to optimize the temperature of the chilled water. After the cooling water temperature is optimized, the cooling water can be supplied to semiconductor processing tool 245. Level sensor 330 in tank 250 can be used for various purposes.

[0095] Figure 3B The illustration shows a level sensor 330 placed within a tank 250. In some embodiments of this disclosure, the level sensor 330 can relay water level information to a system configured to maintain a specific water level in the tank 250. In some embodiments of this disclosure, the level sensor 330 can be configured to relay a low water level notification to an alarm system 275. Figure 2 Alarm system 275 can be configured to shut down semiconductor processing tool 245 that relies on cooling water system 240 for operation. Such shutdown may have adverse effects on semiconductor processing tool 245. For example, products being processed by semiconductor processing tool 245 may need to be scrapped, semiconductor processing tool 245 itself may need maintenance before restarting, and workers' and / or technicians' time may need to be unnecessarily consumed to bring the processing system back online.

[0096] like Figure 3A As shown, the liquid level sensor 310 configured in the humidifier unit 230 can be positioned at a point sufficient to maintain the water level, keeping the heating coil 320 submerged. In some embodiments disclosed herein, when the heating coil 320 is activated and the load is removed (e.g., water is not in contact with the heating coil 320), the heating coil 320 may overheat, causing damage to the humidifier unit 230. For example, an overheated heating coil 320 may deform, leading to a failure requiring repair or replacement. Similarly, in Figure 3B In this process, a liquid level sensor 310 configured in the tank 250 can be installed in the tank 250 to maintain the water level at a level sufficient to ensure that the semiconductor processing tool 245, which receives cooling water from the cooling water system 240, receives a constant flow of cooling water.

[0097] In some embodiments of this disclosure, the level sensor 310 may be connected to a timing system configured to assess the duration of a low water level event. In some embodiments, a low water level event may be indicated when at least one level sensor 310 is exposed to air and not in contact with water. For example, an alarm system may be triggered when a low water level event lasting approximately one second is detected, causing the semiconductor processing tool 245 to shut down. In some embodiments of this disclosure, a low water level event lasting approximately one second may not indicate a catastrophic low water level event. For example, the movement of water during an earthquake may expose the level sensor 310 for a sufficiently long period to indicate a false low water level event.

[0098] Figure 4A , Figure 4B , Figure 4C and Figure 4D It is a diagram showing, for example, the impact of an earthquake on water level movement in a water supply system 200. Figure 4A The humidifier unit 230 is shown under normal conditions, for example, when there is no earthquake. Under normal conditions, the water level is static and horizontal, as shown by the horizontal dashed line 410. Figure 4B The humidifier unit 230 is shown during an earthquake event. In some embodiments, the humidifier unit 230 may shake during an earthquake, and in some cases shake violently, causing the water level in the humidifier unit 230 to fluctuate dramatically, as indicated by the wavy dashed line 420. It is noteworthy that the water level during an earthquake event, as indicated by the wavy dashed line 420, can fluctuate significantly enough to expose the level sensor 310 to air for a sufficient period of time to trigger a 1-second alarm in the alarm system 275.

[0099] Figure 4C The image shows tank 250 in cooling water system 240 under normal conditions, such as when no earthquake has occurred. Under normal conditions, the water level is static and horizontal, as shown by the horizontal dashed line 430. Figure 4D The tank 250 is shown during an earthquake event. In some embodiments, the tank 250 may shake during an earthquake, causing violent fluctuations in the water level within the tank 250, as indicated by the wavy dashed line 440. It is noteworthy that the water level during an earthquake event, as indicated by the wavy dashed line 440, can fluctuate significantly enough to expose the level sensor 330 to air for a sufficient period of time to trigger a 1-second alarm in the alarm system 275.

[0100] In some embodiments, the second level sensor 330 may be configured to be substantially flush with the first level sensor 330 in the tank 250. Similarly, the two level sensors 310 may be positioned substantially horizontally relative to each other within the humidifier unit 230. Figure 3AAs shown, the liquid level sensor 310 configured in the humidifier unit 230 can be positioned at a point sufficient to maintain the water level, for example, by keeping the heating coil 320 submerged. Therefore, a redundant sensor system is provided to further protect semiconductor processing tools from damage, prevent product scrapping, and save worker time from unnecessary repairs or replacements.

[0101] In some embodiments of this disclosure, the alarm system 275 may be triggered before the fluctuating water level returns to a level that can be sensed by the level sensor 310, resulting in a false alarm. For example, if the water level begins to fluctuate, the water will rise and fall above the level sensor 310. Thus, the level sensor 310 can sense water during the peaks and water loss during the troughs. In some embodiments of this disclosure, the alarm system 275 may be triggered if the trough of the wave lasts longer than 1 second. Since the water level is only fluctuating and water still exists in the humidifier unit 230, the low water alarm triggered by the alarm system 275 is false. The embodiments of this disclosure resolve this false alarm.

[0102] Figure 5A This is a schematic diagram illustrating a false alarm prevention system 500 according to some embodiments. In some embodiments of this disclosure, the false alarm prevention system 500 may be configured to mitigate the occurrence of false alarms in the humidifier system 210. In some embodiments of this disclosure, a delay circuit 510 may be electrically coupled to a level sensor 310. For example, the delay circuit 510 may be configured to delay the signal sent from the level sensor 310 to the alarm system 275. Therefore, in the event of an earthquake or any other cause leading to fluctuations in the water level within the humidifier unit 230, false alarms can be prevented by delaying the signal sent from the level sensor 310 to the alarm system 275.

[0103] In some embodiments of this disclosure, switch 520 may be configured to send the level sensor signal directly to delay circuit 510 from the signal transmitted from level sensor 310 to alarm system 275 and / or semiconductor processing tool 245 itself. In some embodiments of this disclosure, switch 520 may be set to activate after a low level event signal persists for up to approximately 1 second (e.g., approximately 0.99 seconds). Therefore, the low level event signal can be diverted from alarm system 275 (or semiconductor processing tool 245 with alarm system 275) to delay circuitry, which provides a timing buffer for the level sensing system to return to a preset configuration without triggering a false alarm and unnecessarily shutting down semiconductor processing tool 245.

[0104] In some embodiments disclosed herein, Figure 5BA false alarm prevention system 501 configured to mitigate false alarms in the cooling water system 240 is shown. In some embodiments disclosed herein, a delay circuit 530 may be electrically coupled to a level sensor 330. For example, the delay circuit 530 may be configured to delay the signal sent from the level sensor 330 to the alarm system 275. Thus, in the event of an earthquake or any other event causing fluctuations in the water level within the tank 250, false alarms can be prevented by delaying the signal sent from the level sensor 330 to the alarm system 275. Additionally, a switch 540 may be configured to send the level sensor signal directly from the level sensor 330 to the alarm system 275 and / or to the semiconductor processing tool 245 itself (e.g., the switch 540 may be activated).

[0105] Figure 6A , Figure 6B and Figure 6C This is a diagram showing the delay in signals sent from the level sensor 310 to the alarm system 275 and / or to a semiconductor processing tool 245 integrating the alarm system 275, according to some embodiments of this disclosure. In some embodiments, a level sensor system without false alarm prevention systems 500, 501 is configured to detect the water level per second for a first duration (e.g., approximately 1 second). For example, Figure 6A The diagram illustrates the preset operation indicated by plot line 610, wherein the level sensor system can be activated (in other words, sense) for approximately 1 second as indicated by sensing interval 615, deactivated (in other words, rest) for approximately 1 second as indicated by rest interval 617, and then activated (sense) for approximately 1 second as indicated by sensing interval 618. Therefore, in some embodiments, when no water is sensed after the 1-second duration, alarm system 275 can be activated as indicated by plot line 620 corresponding to the end of the first 1-second sensing interval 615, and semiconductor processing tool 245 can be shut down.

[0106] In some embodiments, when employing false alarm prevention systems 500, 501, the sensor signal and sensor detection rate may be delayed for a second duration (longer than the first duration) before being transmitted to alarm system 275 and / or semiconductor processing tool 245 having integrated alarm system 275. In some embodiments, the second duration may be in the range of about 4 seconds to about 60 seconds. If no water is detected after the second duration (e.g., falling within a predetermined value in the range of about 4 seconds to about 60 seconds), a signal is transmitted to alarm system 275 and / or semiconductor processing tool 245 having integrated alarm system 275.

[0107] In some embodiments, the low water level event signal can be customized for a specific water supply system 200. For example, the second duration can be optimized for highly sensitive systems and / or more robust systems. In some embodiments, highly sensitive systems may require strict control of the water supply system 200. Therefore, the second duration can be a short duration, for example, from about 4 seconds to about 10 seconds. In some embodiments, a longer second duration can be used to protect more robust systems from false alarms. For example, robust systems are less susceptible to low water level events and only require a second duration of about 30 seconds to about 60 seconds. In some embodiments, false alarm prevention systems 500, 501 can be customized for specific applications.

[0108] For example, Figure 6B The implementation methods of false alarm prevention systems 500 and 501 are illustrated graphically. Figure 6B In this context, the sensor signal indicated by the plotting line 630 includes a signal delay indicated by the delay sensing interval 635. In some embodiments, the delay sensing interval 635 can be derived from... Figure 6A The 1-second preset sensing interval 615 is extended to a second delayed sensing interval (e.g., about 4 seconds to about 60 seconds). After the maximum delayed sensing time 645 is reached, the alarm system 275 can be activated as indicated by the plotting line 640 corresponding to the end of the delayed sensing interval 635, and the semiconductor processing tool 245 can be shut down.

[0109] Additionally, in some embodiments disclosed herein, false alarm prevention systems 500, 501 can revert to preset operation, wherein the level sensor system can activate (in other words, sense) for approximately 1 second, deactivate (in other words, rest) for approximately 1 second, and then reactivate (in other words, sense) for approximately 1 second. In some embodiments, false alarm prevention systems 500, 501 can revert to preset operation after alarm system 275 triggers a low water level alarm. For example, they can revert after an alarm triggering event occurs after a signal delay event. In some embodiments, if no water is detected after the maximum signal delay (e.g., after approximately 4 seconds to approximately 60 seconds), a signal is transmitted to alarm system 275 and / or semiconductor processing tool 245 having integrated alarm system 275.

[0110] Alarm system 275 can trigger a low water level alarm and continue to shut down semiconductor processing tool 245. (Reference) Figure 5A and Figure 5BSwitches 520 and 540 can be configured to switch from transmitting signals from level sensors 310 and 330 to delay circuits 510 and 530 back to directly transmitting level sensor signals to alarm system 275 and / or to a semiconductor processing tool 245 that itself integrates alarm system 275 (e.g., switches 520 and 540 can be deactivated). Therefore, unnecessary shutdowns can be avoided, and necessary shutdowns can be implemented in the event of a catastrophic low water level event.

[0111] refer to Figure 6C This figure depicts a false alarm prevention system reverting to a preset operation. Notably, plot line 660, indicating that alarm system 275 is activated at point 665, depicts the preset operation. As shown by plot line 650, if level sensors 310, 330 detect water, alarm system 275 will not trigger after a 1-second sensing interval 655. However, if no water is detected during a later sensing interval 670, alarm system 275 may trigger, or in some embodiments, false alarm prevention systems 500, 501 will take control of the signal, restarting the delay cycle.

[0112] In some embodiments disclosed herein, see Figure 5A and Figure 5B The delay circuits 510 and 530 can increase the alarm trigger time from a first duration (e.g., approximately 1 second) to a second duration longer than the first duration (e.g., from approximately 4 seconds to approximately 60 seconds). The increased duration before sending a low water level signal to the alarm system allows any fluid movement to subside, for example, Figure 4A and Figure 4C The normal conditions shown allow level sensors 310 and 330 to detect the correct water level. In some embodiments disclosed herein, a low water level event lasting longer than the second duration (e.g., from about 4 seconds to about 60 seconds) can indicate a catastrophic low water level event. Therefore, a delay in the transmission of the low water level signal from level sensor 310 to the alarm system for a duration exceeding the second duration can be dangerous for the processing system and / or product.

[0113] Now we arrive Figure 7 This illustrates the use of some embodiments according to this disclosure. Figure 5A and Figure 5B The false alarm prevention systems 500 and 501 are described in method 700. The operation described in method 700 can be performed by, for example... Figure 2 The water supply system 200 is used to perform this operation. It should be understood that not all operations need to be performed according to the disclosure provided herein, and one or more additional operations may be performed. Furthermore, some operations may be performed simultaneously or in a different order than that shown in method 700.

[0114] In some embodiments of this disclosure, at operation 710, the method of configuring and using the false alarm prevention system 500 may include sensing the liquid level in a tank using at least one of the level sensors 310, 330. In some embodiments of this disclosure, the sensing operation may be configured to determine whether water is in contact with the level sensors 310, 330. If water is in contact with the level sensors 310, 330, the system continues with a preset operation. In some embodiments of this disclosure, the preset operation includes determining whether water is in contact with the level sensors 310, 330 at predetermined time intervals (e.g., approximately every 1 second), such as... Figure 6A or Figure 6C As shown.

[0115] If no water comes into contact with the level sensors 310, 330 for a first duration (e.g., up to about 1 second, such as about 0.99 seconds), then at operation 720, the method of configuring and employing the false alarm prevention systems 500, 501 may include detecting a change in water level in the humidifier unit 230 or tank 250 for up to the first duration using at least one level sensor 310, 330. According to some embodiments, after detecting a change in water level, at operation 730, at least one level sensor 310, 330 may be configured to transmit a low liquid event signal (e.g., a low water level event signal) to the false alarm prevention systems 500, 501. In some embodiments, switches 520, 540 may then activate the low water level event signal transmitted from the level sensors 310, 330 and redirect it from transmission to the alarm system 275 and / or a semiconductor processing tool 245 having an integrated alarm system 275 to the delay circuits 510, 530.

[0116] In some embodiments disclosed herein, at operation 740, the method of employing the false alarm prevention systems 500, 501 may include activating at least one delay circuit 510, 530. In some embodiments, at operation 750, the delay circuits 510, 530 may delay a low water level event signal sent from the level sensors 310, 330 to the alarm system 275 and / or the semiconductor processing tool 245 having the integrated alarm system 275 for a second duration longer than a first duration (e.g., ranging from about 4 seconds to about 60 seconds). After the second duration is reached (e.g., between about 4 seconds and about 60 seconds), and if the level sensors 310, 330 are still reading the low water level event signal, then at operation 760, the low water level event signal from the level sensors 310, 330 is transmitted to the alarm system 275 and / or the semiconductor processing tool 245 having the integrated alarm system 275, and a low water level alarm may be triggered. Additionally, in some embodiments disclosed herein, after operation 770 reaches its maximum predetermined duration, switches 520, 540 can resume sending signals directly from level sensors 310, 330 to alarm system 275 and / or semiconductor processing tool 245 having integrated alarm system 275, and continue to determine whether there is water on level sensors 310, 330 based on a first time period (e.g., at most about 1 second interval). The determination of whether water is present on the level sensor is resumed based on the first time period.

[0117] In some embodiments disclosed herein, the system can be configured to prevent false low water level alarms in a system temperature and humidity control (STHC) system. This system includes a reservoir configured to contain liquid and a sensor system configured to delay the alarm system for a predetermined duration. In some embodiments, the sensor system includes a sensor and a delay circuit. The sensor is configured to determine the fluid level in the reservoir and send a signal indicating the fluid level to the alarm system. The delay circuit is coupled to the level sensor and configured to delay the signal sent to the alarm system for the predetermined duration.

[0118] In some embodiments, the false alarm prevention system further includes a second level sensor. In some embodiments, the second level sensor is substantially flush with a first level sensor within a reservoir. In some embodiments, the false alarm prevention system further includes a second delay circuit communicatively coupled to the second level sensor. In some embodiments, the second level sensor and the second delay circuit are communicatively coupled to a semiconductor processing tool having a level alarm system. In some embodiments, the false alarm prevention system further includes a second switch located between the second level sensor and the second delay circuit. In some embodiments, the first level sensor and the first delay circuit are communicatively coupled to the semiconductor processing tool having a level alarm system. In some embodiments, the reservoir is flowably connected to the semiconductor processing tool. In some embodiments, the false alarm prevention system further includes a first switch located between the first level sensor and the first delay circuit. In some embodiments, the reservoir is flowably connected to a liquid source. In some embodiments, the alarm system is configured to shut off the semiconductor processing tool.

[0119] In some embodiments disclosed herein, at least a first level sensor may be configured at a predetermined level in the reservoir to ensure sufficient fluid content. A first delay circuit may be communicatively coupled to the first level sensor and configured to delay the transmission of a first signal from the first level sensor to an alarm system, wherein the first signal is a low level event signal. In some embodiments, a second level sensor is configured to be substantially flush with the first level sensor, and a second delay circuit is communicatively coupled to the second level sensor and configured to delay the transmission of a second signal from the second level sensor to the alarm system, wherein the second signal is a low level event signal, wherein the first level sensor and the first delay circuit, as well as the second level sensor and the second delay circuit, comprise a redundant sensor system.

[0120] In some embodiments, the level sensing system further includes a first switch located between the first level sensor and the first delay circuit, configured to transfer a first low level event signal from the alarm system to the first delay circuit. In some embodiments, the level sensing system further includes a second switch located between the second level sensor and the second delay circuit, configured to transfer a second low level event signal from the alarm system to the second delay circuit. In some embodiments, the first level sensor, the first delay circuit, the second level sensor, and the second delay circuit are disposed within a storage tank.

[0121] In some embodiments disclosed herein, a method includes sensing a liquid level in a tank using at least one level sensor. A change in the liquid level in the tank is detected using the at least one level sensor during a first time period. A low liquid level event signal is transmitted from the level sensor. At least one delay circuit is activated. The low liquid level event signal is delayed for a second time period, wherein the low liquid level event signal causes a semiconductor processing tool to shut down.

[0122] In some embodiments, detecting changes in the liquid level within the tank includes detecting multiple peaks and multiple troughs in the liquid. In some embodiments, delaying a low-level event signal includes transferring the low-level event signal to at least one delay circuit. In some embodiments, transferring the low-level event signal to at least one delay circuit includes activating a switch. In some embodiments, the false alarm prevention method further includes disabling the switch to restore a preset operation.

[0123] According to some embodiments of this disclosure, a false alarm prevention system includes a reservoir and a level sensor system. The reservoir is configured to contain liquid. The sensor system is configured to delay an alarm system for a predetermined duration. The sensor system includes a first level sensor and a first delay circuit. The first level sensor is located at a predetermined liquid level in the reservoir and configured to determine the liquid level in the reservoir and transmit a first signal indicating the liquid level to the alarm system. The first delay circuit is communicatively coupled to the first level sensor and configured to delay the first signal sent to the alarm system for a predetermined duration.

[0124] According to some embodiments of this disclosure, a liquid level sensing system includes a first liquid level sensor, a first delay circuit, a second liquid level sensor, and a second delay circuit. The first liquid level sensor is located at a predetermined liquid level in a storage tank and configured to determine the liquid level in the storage tank and transmit a first signal indicating the liquid level to an alarm system. The first delay circuit is communicatively coupled to the first liquid level sensor and configured to delay the transmission of a first signal to the alarm system for a predetermined duration, wherein the first signal is a first low liquid level event signal. The second liquid level sensor is substantially flush with the first liquid level sensor. The second delay circuit is communicatively coupled to the second liquid level sensor and configured to delay the transmission of a second signal from the second liquid level sensor to the alarm system, wherein the second signal is a second low liquid level event signal, and wherein the first liquid level sensor and the first delay circuit, as well as the second liquid level sensor and the second delay circuit, constitute a redundant sensing system.

[0125] According to some embodiments of this disclosure, a false alarm prevention system includes a reservoir and a level sensor system. The reservoir is configured to contain liquid. The sensor system is configured to delay an alarm system for a predetermined duration. The level sensor system includes a first level sensor, a first delay circuit, a second level sensor, and a second delay circuit. The first level sensor is located at a predetermined level in the reservoir and configured to determine the level in the reservoir and transmit a first signal indicating the level to the alarm system. The first delay circuit is communicatively coupled to the first level sensor and configured to delay the first signal sent to the alarm system for a predetermined duration, wherein the first signal is a first low level event signal. The second level sensor is substantially flush with the first level sensor. The second delay circuit is communicatively coupled to the second level sensor and configured to delay the transmission of a second signal from the second level sensor to the alarm system, wherein the second signal is a second low level event signal, wherein the first level sensor and the first delay circuit, as well as the second level sensor and the second delay circuit, comprise a redundant sensor system.

[0126] It should be understood that the [Implementation] section, but not the [Abstract] section, is intended to interpret the claims. The [Abstract] section may set forth one or more, but not all, possible embodiments of this disclosure as contemplated by the inventors, and therefore is not intended to limit the appended claims in any way.

[0127] The foregoing outlines the features of several embodiments, enabling those skilled in the art to better understand the nature of this disclosure. Those skilled in the art should understand that this disclosure can readily serve as the basis for designing or modifying other processes and structures to achieve the same purposes and / or advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of this disclosure.

Claims

1. A false positive prevention system, characterized by, Comprising: a reservoir configured to hold a liquid; and a liquid level sensor system configured to delay an alarm system by a predetermined duration, the liquid level sensor system comprising: a first liquid level sensor positioned at a predetermined liquid level in the reservoir and configured to determine a liquid level in the reservoir and transmit a first signal indicative of the liquid level to the alarm system; and a first delay circuit communicatively coupled to the first liquid level sensor and configured to delay the first signal transmitted to the alarm system by the predetermined duration.

2. The false positive prevention system of claim 1, wherein, wherein the first liquid level sensor and the first delay circuit are communicatively coupled to a semiconductor processing tool having a liquid level alarm system.

3. The false positive prevention system of claim 1 or 2, wherein, wherein the reservoir is flowably connected to a semiconductor processing tool.

4. The false positive prevention system of claim 1 or 2, wherein, further comprising a first switch positioned between the first liquid level sensor and the first delay circuit.

5. The false positive prevention system of claim 1 or 2, wherein, wherein the reservoir is flowably connected to a liquid source.

6. A liquid level sensor system characterized by, Comprising: a first liquid level sensor positioned at a predetermined liquid level in a reservoir and configured to determine a liquid level in the reservoir and transmit a first signal indicative of the liquid level to an alarm system; a first delay circuit communicatively coupled to the first liquid level sensor and configured to delay the first signal transmitted to the alarm system by a predetermined duration, wherein the first signal is a first low liquid level event signal; a second liquid level sensor substantially level with the first liquid level sensor; and a second delay circuit communicatively coupled to the second liquid level sensor and configured to delay transmission of a second signal from the second liquid level sensor to the alarm system, wherein the second signal is a second low liquid level event signal, wherein the first liquid level sensor and the first delay circuit and the second liquid level sensor and the second delay circuit comprise a redundant sensor system.

7. The liquid level sensor system of claim 6, wherein, further comprising a first switch positioned between the first liquid level sensor and the first delay circuit and configured to divert the first low liquid level event signal from the alarm system to the first delay circuit.

8. A liquid level sensor system as claimed in claim 6 or 7, characterised in that, further comprising a second switch positioned between the second liquid level sensor and the second delay circuit and configured to divert the second low liquid level event signal from the alarm system to the second delay circuit.

9. The liquid level sensor system of claim 6 or 7, wherein, wherein the first liquid level sensor, the first delay circuit, the second liquid level sensor, and the second delay circuit are disposed within the reservoir.

10. A false positive prevention system, characterized by, Comprising: a reservoir configured to hold a liquid; and a liquid level sensor system configured to delay an alarm system by a predetermined duration, the liquid level sensor system comprising: a first liquid level sensor positioned at a predetermined liquid level in the reservoir and configured to determine a liquid level in the reservoir and transmit a first signal indicative of the liquid level to the alarm system; and a first delay circuit communicatively coupled to the first liquid level sensor and configured to delay the first signal transmitted to the alarm system by the predetermined duration, wherein the first signal is a first low liquid level event signal; a second liquid level sensor substantially level with the first liquid level sensor; and a second delay circuit communicatively coupled to the second liquid level sensor and configured to delay transmission of a second signal from the second liquid level sensor to the alarm system, wherein the second signal is a second low liquid level event signal, wherein the first liquid level sensor and the first delay circuit and the second liquid level sensor and the second delay circuit comprise a redundant sensor system. a second delay circuit communicatively coupled to the second liquid level sensor and configured to delay a second signal from the second liquid level sensor to the alarm system, wherein the second signal is a second low liquid level event signal, wherein the first liquid level sensor and the first delay circuit and the second liquid level sensor and the second delay circuit comprise a redundant sensor system.

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