Process control of semiconductor fabrication equipment using ultrasonic sensors

Abstract

A sensing arrangement coupled with semiconductor fabrication equipment, includes at least one waveguide and an ultrasonic transducer coupled to the waveguide configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide. A controller is configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use outputs to determine one or both of a temperature of a fluid in the equipment, a level of a fluid in the equipment, and / or a temperature of a component of the equipment. The controller is configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment.

Description

PROCESS CONTROL OF SEMICONDUCTOR FABRICATION EQUIPMENTUSING ULTRASONIC SENSORSINCORPORATION BY REFERENCE

[0001] A PCT Request Form is filed concurrently with this specification as part of the present application. Each application that the present application claims benefit of or priority to as identified in the concurrently filed PCT Request Form is incorporated by reference herein in their entireties and for all purposes.BACKGROUND

[0002] Process control of semiconductor fabrication equipment benefits from accurate real time parameter measurement. The measured parameters of interest may include equipment and working fluid temperatures at a number of locations, and temperature and / or fill level of various fluids and fluid containers. Improved techniques for measuring such parameters are desirable.

[0003] The background description provided herein is for the purposes of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor implicitly admitted as prior art against the present disclosure.SUMMARY

[0004] Techniques for process control of semiconductor fabrication equipment are disclosed.

[0005] According to some embodiments, an apparatus for monitoring semiconductor fabrication equipment includes a sensing arrangement coupled with the semiconductor fabrication equipment. The sensing arrangement includes at least one waveguide configured to contact a liquid in a tool for semiconductor fabrication and an ultrasonic transducer coupled to the waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide. The ultrasonic transducer is configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode and (d) wave velocity. The apparatus includes a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use the time of flight, amplitude, propagation modes and wave velocity of the reflected ultrasonic signals to determine one or both of a temperature of the liquid in the tool and a level of the liquid inthe tool, wherein the controller is configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment.

[0006] In some examples, the logic may be configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the temperature of the liquid in the tool. In some examples, the logic may be configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the level of the liquid in the tool. In some examples, the logic may be configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the temperature of the liquid in the tool and the level of the liquid in the tool. In some examples, the logic may be configured to use, at least, flexural and torsional propagation modes to determine the temperature and the level of the liquid in the tool. In some examples, the logic may be configured to use amplitude and / or time of flight in the flexural propagation mode to determine the level of the liquid in the tool. In some examples, the logic may be configured to use amplitude and / or time of flight in the torsional propagation mode to determine the temperature of the liquid.

[0007] In some examples, the tool may be a container for the liquid. In some examples, the container may be an electroplating cell and / or bath. In some examples, the liquid may include one or more of: water, a copper sulphate solution, a nickel plating solution, a tin-silver plating solution, a gold plating solution, sulfuric acid, hydrogen peroxide, and / or hydrofluoric acid. In some examples, the container may be a cleaning bath. In some examples, the liquid may include one or more of: water, hydrogen peroxide, hydrofluoric acid, and / or sulfuric acid. In some examples, the container may be configured as an ampoule for storing liquid deposition precursors. In some examples, the liquid may include one or more of: M0O2CI2, M0CI5, tetraethyl orthosilicate, hexachlorodisilane, and / or triethylphosphate.

[0008] According to some embodiments, an apparatus for monitoring semiconductor fabrication equipment, the apparatus includes a sensing arrangement including: a waveguide disposed within a fluid flow line of the semiconductor fabrication equipment; an ultrasonic transducer, disposed external to the fluid flow line; and a coupling disposed between the ultrasonic transducer and the waveguide. The ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide, the coupling provides a pneumatic seal configured to prevent leakage of fluid from the fluid flow line and the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or moreof: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity. The apparatus includes a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation mode and wave velocity of the reflected ultrasonic signals to determine a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line.

[0009] In some examples, the logic may be configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the plurality of temperatures of the fluid. In some examples, the fluid may be a gas. In some examples, the fluid may be a liquid. In some examples, logic may be configured to use, at least, flexural and torsional propagation modes to determine the plurality of temperatures. In some examples, the logic may be configured to use amplitude and / or time of flight in the torsional propagation mode to determine the plurality of temperatures. In some examples, the waveguide may be configured to avoid interference with flow of the fluid. In some examples, the waveguide may have a long axis generally parallel to the fluid flow line. In some examples, dimensions of the waveguide orthogonal to the long axis are substantially may be less than a diameter of the fluid flow line. In some examples, the dimensions of the waveguide orthogonal to the long axis may be less than 1720thof the diameter of the fluid flow line.

[0010] According to some embodiments, an apparatus for monitoring semiconductor fabrication equipment includes a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement including: at least one ultrasonic transducer coupled to an exterior surface of a tool containing a fluid, the ultrasonic transducer being configured to transmit ultrasonic signals through the exterior surface and to receive reflected ultrasonic signals from the exterior surface, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation modes and wave velocity of the reflected ultrasonic signals to determine one or both of a temperature of the fluid in the tool and a level of the fluid in the tool.

[0011] In some examples, the logic may be configured to use the time of flight of the reflected ultrasonic signals to determine the temperature of the fluid in the tool. In someexamples, the logic may be configured to use a difference in amplitude between the transmitted ultrasonic signals and the received reflected ultrasonic signal to determine the level of the fluid in the tool. In some examples, the ultrasonic transducer may include a piezopolymer. In some examples, the ultrasonic transducer may include polyvinylidene fluoride (PVDF). In some examples, the transducer may be adhered to the exterior surface of the tool.

[0012] In some examples, the tool may be a container for the fluid. In some examples, the container may be an electroplating cell and / or bath. In some examples, the fluid may include one or more of: water, a copper sulphate solution, a nickel plating solution, a tin-silver plating solution, a gold plating solution, sulfuric acid, hydrogen peroxide, and / or hydrofluoric acid. In some examples, the container may be a cleaning bath. In some examples, the fluid may include one or more of water, hydrogen peroxide, hydrofluoric acid, and / or sulfuric acid. In some examples, the container may be configured as an ampoule for storing liquid deposition precursors. In some examples, the liquid may include one or more of Mo02C12, MoC15, tetraethyl orthosilicate, hexachlorodisilane, and / or triethylphosphate.

[0013] In some examples, the tool may be a fluid flow line.

[0014] According to some embodiments, a method of monitoring semiconductor fabrication equipment includes monitoring, with a controller, outputs of a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising at least one ultrasonic waveguide and an ultrasonic transducer. The ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to detect reflected ultrasonic signals from the waveguide. The monitored outputs of the sensing arrangement include the detected reflected signals. The semiconductor fabrication equipment includes: a fluid flow line, the ultrasonic waveguide being disposed on or within the fluid flow line and the controller being configured to determine, from the detected signals, temperature of at least a portion of the fluid flow line; a fluid container or ampoule, the ultrasonic waveguide being disposed on or in the fluid container or ampoule and the controller being configured to determine, from the detected signals, a fill level and / or a temperature of the fluid container or ampoule; and / or a pedestal for supporting a semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen and the controller being configured to determine, from the detected signals, a temperature of at least a portion of the pedestal. The method includes determining, fromthe monitored outputs, with the controller, a condition of the semiconductor fabrication equipment.

[0015] In some examples, the controller may be configured to determine, from the monitored outputs, one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity of the reflected ultrasonic signals. In some examples, the semiconductor fabrication equipment may include the pedestal for supporting the semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen and the controller is configured to determine, from the detected signals, temperatures at multiple locations of the pedestal. In some examples, the condition may include one or more of: temperature of the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal. In some examples, the condition may include a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line. In some examples, the controller may be configured to use, at least, flexural and torsional propagation modes of the reflected ultrasonic signals to determine the temperature of at least the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal. In some examples, the method may include controlling, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment. In some examples, the monitoring outputs of a sensing arrangement may be repeated, at intervals or continuously, so as to provide a substantially closed loop control process. In some examples, the method may include making a determination as to whether the monitored outputs are within acceptable limits. In some examples, the method may include, if the determination indicates the monitored outputs are not within acceptable limits, sounding an alarm, signaling an operator, initiating a soft shutdown of the semiconductor fabrication equipment, aborting an operation of the semiconductor fabrication equipment, or recommending further analysis and / or corrective action.

[0016] According to some embodiments, an apparatus for monitoring semiconductor fabrication equipment includes: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising at least one ultrasonic waveguide and an ultrasonic transducer; and a controller configured to monitor outputs of the sensing arrangement. The ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to detect reflected ultrasonic signals from the waveguideand the monitored outputs of the sensing arrangement include the detected reflected signals. The semiconductor fabrication equipment includes: a fluid flow line, the ultrasonic waveguide being disposed on or within the fluid flow line and the controller being configured to determine, from the detected signals, temperature of at least a portion of the fluid flow line; a fluid container or ampoule, the ultrasonic waveguide being disposed on or in the fluid container or ampoule and the controller being configured to determine, from the detected signals, a fill level and / or a temperature of the fluid container or ampoule; and / or a pedestal for supporting a semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen, the controller being configured to determine, from the detected signals, a temperature of at least a portion of the pedestal. The controller is configured to determine, from the monitored outputs, a condition of the semiconductor fabrication equipment.

[0017] In some examples, the controller may be configured to determine, from the monitored outputs, one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity of the reflected ultrasonic signals. In some examples, the semiconductor fabrication equipment may include the pedestal for supporting the semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen and the controller is configured to determine, from the detected signals, temperatures at multiple locations of the pedestal. In some examples, the condition may include one or more of: temperature of the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal. In some examples, the condition may include a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line. In some examples, the controller may be configured to use, at least, flexural and torsional propagation modes of the reflected ultrasonic signals to determine the temperature of at least the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal. In some examples, the controller may be configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment. In some examples, the controller may be configured to monitor outputs of a sensing arrangement repeatedly, at intervals or continuously, so as to provide a substantially closed loop control process. In some examples, the controller may be configured to make adetermination as to whether the monitored outputs are within acceptable limits. In some examples, the determination may indicate the monitored outputs are not within acceptable limits, the controller is configured to sound an alarm, signal an operator, initiate a soft shutdown of the semiconductor fabrication equipment, abort an operation of the semiconductor fabrication equipment, or recommend further analysis and / or corrective action.

[0018] According to some embodiments, an apparatus for monitoring semiconductor fabrication equipment, the equipment including a pedestal configured to support a semiconductor substrate and a showerhead, the apparatus including: a sensing arrangement comprising at least one waveguide enclosed by a platen disposed on the pedestal; an ultrasonic transducer coupled to the waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals and to determine, from the detected signals, a temperature of at least a portion of the pedestal.

[0019] In some examples, the logic may be configured to use the time of flight, amplitude, propagation mode and / or wave velocity of the reflected ultrasonic signals to determine the temperature of at least the portion of the pedestal. In some examples, the semiconductor substrate may be disposed on the platen, between the platen and the showerhead. In some examples, the platen may include an upper plate and a lower plate, and the waveguide may be disposed between, and enclosed by, the upper plate and the lower plate. In some examples, the waveguide may be within a groove in an interior surface of at least one of the upper plate and the lower plate. In some examples, the waveguide may include a strip having a rectangular cross section. In some examples, the rectangular cross section may have a width and a length, the length being at least five times the width. In some examples, the waveguide may include a plurality of straight segments, adjacent straight segments being coupled by folds. In some examples, the waveguide may have a curvilinear geometry. In some examples, the waveguide may include a first unit and a second unit. In some examples, the first unit may include a first curved portion and the second unit may include a second curved portion, the second curved portion being approximately coaxial with the first curved portion.

[0020] In some examples, the controller may be configured to determine, from the detected signals, a respective temperature of multiple locations of the pedestal.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A is a schematic diagram of an example apparatus in accordance with some implementations.

[0022] Figure IB is a schematic diagram of an example multi-station tool in accordance with some embodiments.

[0023] Figure 2 illustrates a block diagram of a semiconductor fabrication system, according to some implementations.

[0024] Figure 3 presents a flowchart of an example process for monitoring semiconductor fabrication equipment, according to some implementations.

[0025] Figure 4 illustrates a use case of a sensing arrangement for monitoring fluid temperatures and / or fill level, according to some implementations.

[0026] Figure 5 illustrates a use case of a sensing arrangement for monitoring fluid temperatures in a fluid flow line, according to some implementations.

[0027] Figure 6 illustrates a use case of a sensing arrangement for fluid temperatures and / or fill level, according to some implementations.

[0028] Figures 7A-7C illustrate a use case of a sensing arrangement for monitoring pedestal temperature, according to some implementations.DETAILED DESCRIPTION

[0029] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all these specific details. In other instances, well- known process operations have not been described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments will be described in conjunction with the specific embodiments, it will be understood that it is not intended to limit the disclosed embodiments.

[0030] Figure 1A shows a highly simplified schematic of a semiconductor fabrication system with which the presently disclosed techniques may be implemented. The system 100 includes various equipment configured for depositing films on or over a semiconductor substrate utilizing any number of processes. For example, the system 100 may be adapted for performing chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), atomic layer deposition (ALD) and / or atomic layer epitaxy (ALE).

[0031] In the illustrated example, the system 100 includes a single process station 102 comprising a process chamber enclosing, in an interior volume, a single substrate holder 108 (that may be referred to hereinbelow as a pedestal) and a substrate 112, disposed on the pedestal 108. The interior volume may be maintained under vacuum by a vacuum pump 118. A gas distributor 106 (that may be referred to hereinbelow as a s showerhead) is fluidically coupled with a gas delivery system 101 and may be configured to permit delivery of film precursors, for example, as well as carrier and / or purge and / or process gases, secondary reactants, and / or cleaning agents, for example.

[0032] In the illustrated example, gas delivery system 101 includes a mixing vessel 104 for blending and / or conditioning process gases for delivery to showerhead 106. One or more mixing vessel inlet valves 120 may control introduction of process gases to mixing vessel 104. Particular reactants may be stored in liquid or solid form prior to vaporization and subsequent delivery to the process chamber of process station 102. The implementation of Figure 1A includes a vaporization point 103 for vaporizing liquid reactant to be supplied to mixing vessel 104. In some implementations, vaporization point 103 may include a heated liquid injection module. In some other implementations, vaporization point 103 may include a heated vaporizer. In yet other implementations, vaporization point 103 may be eliminated from the process station. In some implementations, a liquid flow controller upstream of vaporization point 103 may be provided for controlling a mass flow of liquid for vaporization and delivery to process station 102. Alternatively, or in addition, some process chemicals (e.g., precursors) may be stored in solid or liquid form in ampoules, the ampoules being configured to facilitate vaporization of the chemicals and permit resulting precursor vapor to be mixed with the carrier gas which may carry the resulting precursor vapor to the process chamber 102.

[0033] The showerhead 106 may operate to distribute process gases and / or reactants (e.g., film precursors) toward the substrate 112, the flow of which may be controlled by one or more valves upstream from the showerhead (e.g., valves 105, 120, 125). In the implementation depicted in Figure 1A, the substrate 112 is depicted as located beneath showerhead 106 and is shown disposed on the pedestal 108. The showerhead 106 may include any suitable shape and may include any suitable number and arrangement of ports for distributing process gases to the substrate 112. In some implementations involving two or more stations, the gas delivery system 101 may include valves or other flow control structures upstream from the showerhead, which can independently control the flow of process gases and / or reactants to each station so as to permit gas flow to onestation while preventing gas flow to one or more other stations. Moreover, the gas delivery system 101 may be configured to independently control process gases and / or reactants delivered to each station in a multi-station apparatus such that the gas composition provided to different stations is different; e.g., the partial pressure of a gas component may vary between stations at the same time.

[0034] In the implementation of Figure 1A, gas volume 107 is depicted as being located beneath showerhead 106. In some implementations, the pedestal 108 may be raised or lowered to expose the substrate 112 to gas volume 107 and / or to vary the size of the gas volume 107. A separation distance between the pedestal 108 and the showerhead 106 may be referred to as a “gap.” In some implementations, the pedestal 108 may be lowered and / or raised during portions of a deposition process to modulate process pressure, reactant concentration, etc., within the gas volume 107.

[0035] In the illustrated example, the showerhead 106 and the pedestal 108 are electrically coupled to a radio frequency (RF) signal generator 114 and a matching network 116 for coupling power to a plasma generator. For example, the showerhead 106 may function as an electrode for coupling radio frequency power into the process station 102. The RF signal generator 114 and the matching network 116 may be operated at any suitable RF power level and be configured to form plasma having a desired composition of radical species, ions, and electrons. In addition, RF signal generator 114 may provide RF power having more than one frequency component, such as a low-frequency component (e.g., less than about 2 MHz) as well as a high frequency component (e.g., greater than about 2 MHz). In some implementations, plasma ignition and maintenance conditions are controlled with appropriate hardware and / or appropriate machine-readable instructions in a system controller which may provide control instructions via a sequence of input / output control instructions.

[0036] For clarity of illustration, the processing apparatus 100 is depicted in Figure 1A as a standalone station (102) of a process chamber for maintaining a low-pressure environment. However, some fabrication tools employ a plurality of process stations such as shown in Figure IB, which schematically depicts an implementation of a multistation fabrication tool 150. The fabrication tool 150 employs a process chamber 165 that includes multiple fabrication process stations, each of which may be used to perform processing operations on a substrate held in a wafer holder (such as, e.g., pedestal 108 of Figure 1A). In the implementation of Figure IB, the process chamber 165 is shown as having four process stations 151, 152, 153, and 154. However, in certain otherimplementations, multi-station processing apparatuses may have more or fewer process stations depending on the implementation and, for instance, the desired level of parallel wafer processing, size / space constraints, cost constraints, etc. Figure IB additionally shows substrate handler robot 175, which may operate under the control of system controller 190, configured to move substrates from a loading port 180, into multi-station process chamber 165, and onto one of process stations 151, 152, 153, and 154.

[0037] The system controller 190 may be configured to control process conditions and hardware states of fabrication tool 150. It may interact with one or more sensors, gas flow subsystems, temperature subsystems, and / or plasma subsystems — collectively represented as block 191 — to control process gas flow, thermal conditions, and plasma conditions as appropriate for controlling a fabrication process. System controller 190 and subsystems 191 may act to implement a recipe or other process conditions in the stations of process chamber 165.

[0038] In multi- station fabrication tools, an RF signal generator may be coupled to an RF signal distribution unit, which is configured to divide the power of the input signal into, for example, four output signals. Output signals from an RF signal distribution unit may possess similar levels of RF voltage and RF current, which may be conveyed to individual stations of a multi-station fabrication tool.

[0039] Figure 2 illustrates a block diagram of a semiconductor fabrication system, according to some implementations. The system 200 includes semiconductor fabrication equipment 210 and a controller 290 communicatively coupled with the semiconductor fabrication equipment 210 and with a sensing arrangement 230. The sensing arrangement 230 may be or include an ultrasonic transducer coupled to a waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide. The ultrasonic transducer may be further configured to detect, for the reflected ultrasonic signals: (a) time of flight, (b) amplitude, and (c) propagation mode. Advantageously, the controller 290 may be configured to control the semiconductor fabrication equipment 210 and the sensing arrangement 230. The controller 290 may be configured to determine, from the monitored outputs, a condition of the semiconductor fabrication equipment. The controller 290 may be configured to monitor and analyze outputs of the sensing arrangement 230 so as to implement, for example, closed loop process control of a process being performed by the semiconductor fabrication equipment 210. Alternatively or in addition, the controller 290 may form a health assessment of the semiconductor fabrication equipment based on the analyzedoutputs of the sensing arrangement 330. Based on the health assessment, the controller 290 may be configured to sound an alarm, signal an operator, initiate a soft-shutdown or abort, recommend further analysis and / or corrective action.

[0040] Without limitation, the semiconductor fabrication equipment 210 may include the process station 102, a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating bath, chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a deposition chamber or module, an etch chamber or module, an ion implantation chamber or module, a track chamber or module, and / or any other semiconductor processing systems that may be associated with or used in the fabrication and / or manufacturing of semiconductor wafers.

[0041] Depending on the process step or steps to be performed by the tool, the controller 290 might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

[0042] The controller 290, depending on the processing requirements and / or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.

[0043] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out aparticular process on or for a semiconductor wafer or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0044] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g. a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control. Thus as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0045] From the foregoing description, it will be appreciated that semiconductor fabrication equipment contemplated by the present disclosure may include a number of components for which accurate process control is desirable. Achieving that may require measuring parameters of interest such as equipment and working fluid temperatures at multiple locations, and temperature and / or fill level of various fluids and fluidcontainers. For example, some components may be required to operate at or contain fluids at carefully regulated temperatures, and / or contain liquids, where a fill level of the liquid is preferably well controlled.

[0046] In the absence of the presently disclosed techniques, temperatures and fill level information for semiconductor fabrication has been obtained in a variety of ways. For example, fluid containers such as precursor ampoules, plating and cleaning baths have been equipped with separate sensors related to measuring (1) fluid temperature and (2) fill level.

[0047] As a further example, referring to thermal control of pedestal 118, which is preferably maintained at a uniform specified temperature during semiconductor fabrication processes, known techniques include use of thermocouples and / or, as disclosed in Patil, et al., “Sensors for Semiconductor Processing Tools”, WO2023 / 164415, assigned to the assignee of the present application, a waveguide distributed temperature sensor disposed in a cavity of the pedestal.

[0048] The present inventors have appreciated that process control related to measuring equipment and fluid temperatures and liquid fill level information for semiconductor fabrication equipment may advantageously be performed using ultrasonic transducers and / or ultrasonic waveguides. For example, such equipment may be required to operate in hostile environments, including high temperatures (e.g., 150-200°C) and corrosive chemicals. Due to a waveguide’s low signal attenuation, the ultrasonic transducer and associated electronics may be well removed from the actual measurement area. Ultrasonic sensors, in addition to providing temperature and fill level data, may be configured to measure secondary fluid properties such as density, viscosity and dielectric constant, for example, and may be effective to measure liquid levels as small as 10 mm or less. A better understanding of the ultrasonic sensors contemplated herein may be obtained by referring, for example, to Balasubramaniam, et al., US Pat. No. 10,794,870, Balasubramaniam, et al., US Pat. No. 11,022,502, and Raja, et al., US Pat. No. 12,007,361.

[0049] Figure 3 presents a flowchart of an example process 300 for monitoring semiconductor fabrication system. Blocks of process 300 may be implemented by one or more processors of a computing device that may be included in or communicatively coupled with system controller 290, for example.

[0050] At block 302, process 300 may monitor outputs of a sensing arrangement coupled with the semiconductor fabrication system, the sensing arrangement including atleast one ultrasonic waveguide and an ultrasonic transducer. Monitoring the outputs may include processing, with a controller, the outputs to determine a condition of the semiconductor fabrication equipment.

[0051] At block 304, process 300 may, based on the monitored outputs, control an operational parameter of the semiconductor fabrication system equipment. For example, the controller may make a comparison between the determined condition and a desired condition and control the parameter responsive to the comparison. The operational parameter may include, for example, a fluid flow rate, a flow valve position, heater power, etc.

[0052] Optionally, as indicated by dashed process flow line 305, the process 300 may be repeated, at intervals or continuously, so as to provide a substantially closed loop control process.

[0053] Optionally, as indicated by dashed decision block 306, the process 300 may include a determination as to whether or not the monitored outputs are within acceptable limits. If so, the process 300 may be repeated, at intervals or continuously. If not, at block 308 the process may continue by, for example, sounding an alarm, signaling an operator, initiating a soft shutdown of the semiconductor fabrication system, aborting an operation of the semiconductor fabrication system, or recommending further analysis and / or corrective action.

[0054] A number of use cases for the presently disclosed techniques will now be described. In a first example, referring now to Figure 4, a sensing arrangement of apparatus 400 includes a waveguide 460 configured to have a distal portion 461 in contact with a liquid in a tool for semiconductor fabrication. The tool, which may be part of semiconductor fabrication equipment 310, includes, in the illustrated example, a container 441 for liquid. Although the illustrated example presents the container 441 as having a rectilinear form factor, the container may be cylindrical, for example, and / or configured as an ampoule for storing liquid deposition precursors.

[0055] The liquid may include, for example, process chemicals such as deposition precursors (e.g., M0O2CI2, M0CI5, tetraethyl orthosilicate, hexachlorodisilane, and triethylphosphate), liquid for an electroplating cell and / or bath (e.g., water, a copper sulphate solution, a nickel plating solution, a tin-silver plating solution, a gold plating solution, sulfuric acid, hydrogen peroxide, or Hydrofluoric acid) or a cleaning operation (e.g., water, hydrogen peroxide, hydrofluoric acid, or sulfuric acid). The waveguide 460, at least the distal portion 461 of which may contact, or be immersed in, the liquid, may beconfigured with external surfaces, at least, formed of a material compatible with the liquid being sensed. Depending on the liquid, the material may include metal, ceramic or other non-metallic substances.

[0056] An ultrasonic transducer 450 is coupled to a proximal end 462 of the waveguide 460 and configured to transmit ultrasonic signals 442 onto the waveguide and to receive reflected ultrasonic signals 444 from the waveguide. The ultrasonic transducer 450 may be configured to detect, for the reflected ultrasonic signals 444: (a) time of flight, (b) amplitude, and (c) propagation mode and forward the detected information to controller 490. The controller 490 may be configured to monitor outputs of the sensing arrangement, and include logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals to determine one or both of a temperature of the liquid in the tool and a level of the liquid in the tool. The controller 490 may be configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment. Advantageously, the ultrasonic transducer 450 and proximal end 462 of the waveguide may be located in a relatively benign environment, a distance removed from the distal end 462 of the waveguide 460 that may be required to survive exposure to high temperatures and / or corrosive liquids.

[0057] In some implementations, the controller 490 may include logic configured to use the time of flight amplitude, and propagation modes of the reflected ultrasonic signals to determine the temperature of the liquid in the tool. In some implementations, the controller 490 may include logic configured to use the time of flight amplitude, and propagation modes of the reflected ultrasonic signals to determine the level of the liquid in the tool. In some implementations, the controller 490 may include logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals to determine the temperature of the liquid in the tool and the level of the liquid in the tool.

[0058] In some implementations, the controller 490 may include logic configured to use, at least, flexural and torsional propagation modes to determine the temperature and the level of the liquid in the tool. In some implementations, the controller 490 may include logic configured to use amplitude and / or time of flight in the flexural propagation mode to determine the level of the liquid. In some implementations, the controller 490 may include logic configured to use amplitude and / or time of flight in the torsional propagation mode to determine the temperature of the liquid.

[0059] In a further example, referring now to Figure 5, a sensing arrangement of apparatus 500 includes a waveguide 540 disposed within a fluid flow line 552 of the semiconductor fabrication equipment. The fluid flow line 552, which may be part of semiconductor fabrication equipment 310, may be configured to carry a gas or liquid. An ultrasonic transducer 550 is disposed external to the fluid flow line 552. A coupling 553 is disposed between the ultrasonic transducer and the waveguide 540. The ultrasonic transducer 550 is configured to transmit ultrasonic signals 542 onto the waveguide and to receive reflected ultrasonic signals 544 from the waveguide. The ultrasonic transducer 550 may be configured to detect, for the reflected ultrasonic signals 544: (a) time of flight, (b) amplitude, and (c) propagation mode and forward the detected information to controller 590. The controller 590 may include logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals to determine a plurality of temperatures of a fluid in the fluid flow line 552 at two or more locations along a length of the fluid flow line 552.

[0060] In some implementations, the controller 590 may include logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals to determine the plurality of temperatures of the fluid. The fluid may be a gas or a liquid.

[0061] In some implementations, the controller 590 may include logic configured to use, at least, flexural and torsional propagation modes to determine the plurality of temperatures of the fluid. In some implementations, the controller 590 may include logic configured to use amplitude and / or time of flight, in the flexural propagation mode, to determine the plurality of temperatures.

[0062] In some implementations, the waveguide is configured to avoid interference with flow of the fluid. For example, the waveguide 540 has a long axis generally parallel to the fluid flow line and dimensions of the waveguide 540 orthogonal to the long axis are substantially less than a diameter of the fluid flow line 552. For example, dimensions of the waveguide 540 orthogonal to the long axis may be less than 1 / 20111of the diameter of the fluid flow line.

[0063] In another example use case, referring now to Figure 6, a sensing arrangement of apparatus 600 includes an ultrasonic transducer 650 coupled to an exterior surface of a tool 664 containing a fluid. The tool 664 may be, for example, an ampoule or other fluid container, such as for an electroplating cell and / or bath or cleaning bath, or a fluid flow line. The tool 664 may have planar or curved walls (e.g.,have a cylindrical form factor). Depending on the usage of the tool, the walls may be metallic or plastic, and the presently disclosed sensing arrangement works well with either material type. For an electroplating bath, for example, the walls may be formed from a thermoplastic polymer such as polypropylene, polytetrafluoroethylene, a perfluoroalkoxy alkane, low or high density polyethylene, polyethylene terephthalate, polyvinyl chloride, polytetrafluoroethylene, or the like. Ampoules, on the other hand, are more commonly made of stainless steel or aluminum, for example. The ultrasonic transducer 650 is configured to transmit ultrasonic signals 642 through the exterior surface and to receive reflected ultrasonic signals 644 from the exterior surface. The ultrasonic transducer 650 may be configured to detect, for the reflected ultrasonic signals 644: (a) time of flight, (b) amplitude, and (c) propagation mode and forward the detected information to controller 690. The controller 690 may be configured to monitor outputs of the sensing arrangement and include logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals to determine one or both of a temperature of the liquid in the tool and a level of the liquid in the tool.

[0064] In some implementations, the controller 690 may include logic configured to use the time of flight of the reflected ultrasonic signals to determine the temperature of the liquid in the tool. In some implementations, the controller 690 may include logic configured to use a difference in amplitude between the transmitted ultrasonic signals and the received reflected ultrasonic signal to determine the level of the liquid in the tool.

[0065] In some implementations, the ultrasonic transducer 650 may include a piezopolymer. In some implementations, the ultrasonic transducer 650 may include polyvinylidene fluoride (PVDF). In some implementations, the ultrasonic transducer 650 is adhered to the exterior surface of the tool 664. In some implementations, a thermal insulating layer is disposed between the ultrasonic transducer 650 and the exterior surface of the tool 664.

[0066] In a yet further example, referring now to Figure 7 A, an apparatus 700 for monitoring semiconductor fabrication equipment the equipment includes a pedestal 708 and a showerhead 706. The apparatus 700 also includes a sensing arrangement comprising at least one waveguide 740 enclosed by a platen 775 disposed on the pedestal 708, the platen having an upper plate 775a and a lower plate 775b. The waveguide 740 may be disposed between, and enclosed by, the upper plate 775a and the lower plate 775b. An ultrasonic transducer 750 is coupled to the waveguide 740 and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signalsfrom the waveguide. The ultrasonic transducer 750 may be further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and / or (d) wave velocity . A controller 790 is configured to monitor outputs of the sensing arrangement. The controller 790 includes logic configured to use the time of flight, amplitude, propagation modes and / or wave velocity of the reflected ultrasonic signals and to determine, from the detected signals, a temperature of at least a portion of the pedestal. In some implementations, the controller 790 may be configured to determine, from the detected signals, a respective temperature of multiple locations of the pedestal 708.

[0067] The pedestal 708, optionally, may also support a semiconductor substrate 712 disposed on the platen 775, between the platen 775 and the showerhead 706. Interior surfaces of one or both of an upper plate 775a and a lower plate 775b may be configured with grooves within which the waveguide 740 may be disposed.

[0068] Referring now to Figure 7B, in some implementations, the waveguide may be configured as a strip having a rectangular cross section. The waveguide may be configured to exhibit different propagation properties at different temperatures and may include a number of reflecting structures that reflect a propagating wave. Time-of-flight (TOF) of reflected waves may be measured to determine a relationship between waveguide temperature and velocity (or other properties) of reflected waves. The waveguide may include a number of straight segments, adjacent straight segments being coupled by folds configured to be or include reflector structures. Advantageously, acoustic wave propagation modes specific to rectangular geometries may be selected for least amount of dispersion and loss due to leakage of acoustic energy from the waveguide to surrounding structures or atmosphere coupled to the waveguide.

[0069] In some implementations, the waveguide may have a generally cylindrical cross-section that may include for example, a circular or suitable non-circular cross section, such as an oval, ellipsoid, square, hexagonal, or octagonal cross section. In an example implementation illustrated in Figure 7C such a waveguide 740 is configured in a curvilinear geometry to extend along an approximately circular arc or spiral. As illustrated, the waveguide 740 may include a first unit 740(1) and a second unit 740(2). The first unit 740(1) may be configured with a first curved portion and the second unit 740(2) may be configured with a second curved portion, the second curved portion being approximately coaxial with the first curved portion. It will be appreciated that other waveguide geometries are within the contemplation of the present disclosure. Forexample, the waveguide may be configured to follow a zig-zag pattern, or have an approximately square, hexagonal or octagonal form factor.CONCLUSION

[0070] In the description, numerous specific details were set forth in order to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. In other instances, well- known process operations were not described in detail to not unnecessarily obscure the disclosed embodiments. While the disclosed embodiments were described in conjunction with the specific embodiments, it will be understood that the specific embodiments are not intended to limit the disclosed embodiments.

[0071] Numeric ranges are inclusive of the numbers defining the range. It is intended that every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

[0072] The headings provided herein are not intended to limit the disclosure.

[0073] As used herein, the singular terms “a,” “an,” and “the” include the plural reference unless the context clearly indicates otherwise. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated.

[0074] Various computational elements including processors, memory, instructions, routines, models, or other components may be described or claimed as “configured to” perform a task or tasks. In such contexts, the phrase “configured to” is used to connote structure by indicating that the component includes structure (e.g., stored instructions, circuitry, etc.) that performs the task or tasks during operation. As such, the unit / circuit / component can be said to be configured to perform the task even when the specified component is not necessarily currently operational (e.g., is not on).

[0075] The components used with the “configured to” language may refer to hardware — for example, circuits, memory storing program instructions executable to implement the operation, etc. Additionally, “configured to” can refer to generic structure (e.g., generic circuitry) that is manipulated by software and / or firmware (e.g., an FPGA or a general-purpose processor executing software) to operate in manner that is capableof performing the recited task(s). Additionally, “configured to” can refer to one or more memories or memory elements storing computer executable instructions for performing the recited task(s). Such memory elements may include memory on a computer chip having processing logic. In some contexts, “configured to” may also include adapting a manufacturing process (e.g., a semiconductor fabrication facility) to fabricate devices (e.g., integrated circuits) that are adapted to implement or perform one or more tasks.

[0076] It is to be understood that the above disclosure, while focusing on a particular example implementation or implementations, is not limited to only the discussed example, but may also apply to similar variants and mechanisms as well, and such similar variants and mechanisms are also considered to be within the scope of this disclosure. For example, the above disclosure is directed to at least, but not exclusively, the following numbered implementations.

[0077] Implementation 1 : An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising: at least one waveguide configured to contact a liquid in a tool for semiconductor fabrication and an ultrasonic transducer coupled to the waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation modes and wave velocity of the reflected ultrasonic signals to determine one or both of a temperature of the liquid in the tool and a level of the liquid in the tool, wherein the controller is configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment.

[0078] Implementation 2: The apparatus of implementation 1, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the temperature of the liquid in the tool.

[0079] Implementation 3: The apparatus of implementation 1 or implementation 2, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the level of the liquid in the tool.

[0080] Implementation 4: The apparatus of any one of implementations 1 to 3, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the temperature of the liquid in the tool and the level of the liquid in the tool.

[0081] Implementation 5: The apparatus of any one of implementations 1 to 4, wherein the logic is configured to use, at least, flexural and torsional propagation modes to determine the temperature and the level of the liquid in the tool.

[0082] Implementation 6: The apparatus of implementation 5, wherein the logic is configured to use amplitude and / or time of flight in the flexural propagation mode to determine the level of the liquid in the tool.

[0083] Implementation 7: The apparatus of implementation 5, wherein the logic is configured to use amplitude and / or time of flight in the torsional propagation mode to determine the temperature of the liquid.

[0084] Implementation 8: The apparatus of any one of implementations 1 to 7, wherein the tool is a container for the liquid.

[0085] Implementation 9: The apparatus of implementation 8, wherein the container is an electroplating cell and / or bath.

[0086] Implementation 10: The apparatus of implementation 9, wherein the liquid includes one or more of water, a copper sulphate solution, a nickel plating solution, a tinsilver plating solution, a gold plating solution, sulfuric acid, hydrogen peroxide, and / or hydrofluoric acid.

[0087] Implementation 11: The apparatus of implementation 8, wherein the container is a cleaning bath.

[0088] Implementation 12: The apparatus of implementation 11, wherein the liquid includes one or more of: water, hydrogen peroxide, hydrofluoric acid, and / or sulfuric acid.

[0089] Implementation 13: The apparatus of implementation 8, wherein the container is configured as an ampoule for storing liquid deposition precursors.

[0090] Implementation 14: The apparatus of implementation 13, wherein the liquid includes one or more of: M0O2CI2, M0CI5, tetraethyl orthosilicate, hexachlorodisilane, and / or triethylphosphate.

[0091] Implementation 15: An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement including:a waveguide disposed within a fluid flow line of the semiconductor fabrication equipment; an ultrasonic transducer, disposed external to the fluid flow line; and a coupling disposed between the ultrasonic transducer and the waveguide; wherein: the ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide; the coupling provides a pneumatic seal configured to prevent leakage of fluid from the fluid flow line; and the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation mode and wave velocity of the reflected ultrasonic signals to determine a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line.

[0092] Implementation 16: The apparatus of implementation 15, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the plurality of temperatures of the fluid.

[0093] Implementation 17: The apparatus of implementation 15 or implementation 16, wherein the fluid is a gas.

[0094] Implementation 18: The apparatus of any one of implementations 15 to 17, wherein the fluid is a liquid.

[0095] Implementation 19: The apparatus of any one of implementations 15 to 18, wherein the logic is configured to use, at least, flexural and torsional propagation modes to determine the plurality of temperatures.

[0096] Implementation 20: The apparatus of implementation 19, wherein the logic is configured to use amplitude and / or time of flight in the torsional propagation mode to determine the plurality of temperatures.

[0097] Implementation 21: The apparatus of any one of implementations 15 to 20, wherein the waveguide is configured to avoid interference with flow of the fluid.

[0098] Implementation 22: The apparatus of implementation 21, wherein the waveguide has a long axis generally parallel to the fluid flow line.

[0099] Implementation 23: The apparatus of implementation 22, wherein dimensions of the waveguide orthogonal to the long axis are substantially less than a diameter of the fluid flow line.

[0100] Implementation 24: The apparatus of implementation 23, wherein the dimensions of the waveguide orthogonal to the long axis are less than 1720thof the diameter of the fluid flow line.

[0101] Implementation 25: An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising: at least one ultrasonic transducer coupled to an exterior surface of a tool containing a fluid, the ultrasonic transducer being configured to transmit ultrasonic signals through the exterior surface and to receive reflected ultrasonic signals from the exterior surface, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation modes and wave velocity of the reflected ultrasonic signals to determine one or both of a temperature of the fluid in the tool and a level of the fluid in the tool.

[0102] Implementation 26: The apparatus of implementation 25, wherein the logic is configured to use the time of flight of the reflected ultrasonic signals to determine the temperature of the fluid in the tool.

[0103] Implementation 27: The apparatus of implementation 25 or implementation 26, wherein the logic is configured to use a difference in amplitude between the transmitted ultrasonic signals and the received reflected ultrasonic signal to determine the level of the fluid in the tool.

[0104] Implementation 28: The apparatus of any one of implementations 25 to 27, wherein the ultrasonic transducer comprises a piezopolymer.

[0105] Implementation 29: The apparatus of implementation 28, wherein the ultrasonic transducer comprises polyvinylidene fluoride (PVDF).

[0106] Implementation 30: The apparatus of any one of implementations 25 to 29, wherein the transducer is adhered to the exterior surface of the tool.

[0107] Implementation 31: The apparatus of any one of implementations 25 to 30, wherein the tool is a container for the fluid.

[0108] Implementation 32: The apparatus of implementation 31, wherein the container is an electroplating cell and / or bath.

[0109] Implementation 33: The apparatus of implementation 32, wherein the fluid includes one or more of: water, a copper sulphate solution, a nickel plating solution, a tin-silver plating solution, a gold plating solution, sulfuric acid, hydrogen peroxide, and / or hydrofluoric acid.

[0110] Implementation 34: The apparatus of implementation 31, wherein the container is a cleaning bath.

[0111] Implementation 35: The apparatus of implementation 34, wherein the fluid includes one or more of: water, hydrogen peroxide, hydrofluoric acid, and / or sulfuric acid.

[0112] Implementation 36: The apparatus of implementation 31, wherein the container is configured as an ampoule for storing liquid deposition precursors.

[0113] Implementation 37: The apparatus of implementation 36, wherein the liquid includes one or more of: Mo02C12, MoC15, tetraethyl orthosilicate, hexachlorodisilane, and / or triethylphosphate.

[0114] Implementation 38: The apparatus of any one of implementations 25 to 37, wherein the tool is a fluid flow line.

[0115] Implementation 39: A method of monitoring semiconductor fabrication equipment, the method comprising: monitoring, with a controller, outputs of a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising at least one ultrasonic waveguide and an ultrasonic transducer, wherein: the ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to detect reflected ultrasonic signals from the waveguide; the monitored outputs of the sensing arrangement include the detected reflected signals; and the semiconductor fabrication equipment includes: a fluid flow line, the ultrasonic waveguide being disposed on or within the fluid flow line and the controller being configured todetermine, from the detected signals, temperature of at least a portion of the fluid flow line; a fluid container or ampoule, the ultrasonic waveguide being disposed on or in the fluid container or ampoule and the controller being configured to determine, from the detected signals, a fill level and / or a temperature of the fluid container or ampoule; and / or a pedestal for supporting a semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen and the controller being configured to determine, from the detected signals, a temperature of at least a portion of the pedestal; and determining, from the monitored outputs, with the controller, a condition of the semiconductor fabrication equipment.

[0116] Implementation 40: The method of implementation 39, wherein the controller is configured to determine, from the monitored outputs, one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity of the reflected ultrasonic signals.

[0117] Implementation 41: The method of implementation 39 or implementation 40, wherein the semiconductor fabrication equipment includes the pedestal for supporting the semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen and the controller is configured to determine, from the detected signals, temperatures at multiple locations of the pedestal.

[0118] Implementation 42: The method of any one of implementations 39 to 41, wherein the condition comprises one or more of: temperature of the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal.

[0119] Implementation 43: The method of any one of implementations 39 to 42, wherein the condition comprises a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line.

[0120] Implementation 44: The method of any one of implementations 39 to 43, wherein the controller is configured to use, at least, flexural and torsional propagation modes of the reflected ultrasonic signals to determine the temperature of at least theportion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal.

[0121] Implementation 45: The method of any one of implementations 39 to 44, further comprising controlling, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment.

[0122] Implementation 46: The method of any one of implementations 39 to 45, wherein the monitoring outputs of a sensing arrangement is repeated, at intervals or continuously, so as to provide a substantially closed loop control process.

[0123] Implementation 47: The method of any one of implementations 39 to 46, further comprising making a determination as to whether the monitored outputs are within acceptable limits.

[0124] Implementation 48: The method of implementation 47, further comprising, if the determination indicates the monitored outputs are not within acceptable limits, sounding an alarm, signaling an operator, initiating a soft shutdown of the semiconductor fabrication equipment, aborting an operation of the semiconductor fabrication equipment, or recommending further analysis and / or corrective action.

[0125] Implementation 49: An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising at least one ultrasonic waveguide and an ultrasonic transducer; and a controller configured to monitor outputs of the sensing arrangement, wherein: the ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to detect reflected ultrasonic signals from the waveguide; the monitored outputs of the sensing arrangement include the detected reflected signals; and the semiconductor fabrication equipment includes: a fluid flow line, the ultrasonic waveguide being disposed on or within the fluid flow line and the controller being configured to determine, from the detected signals, temperature of at least a portion of the fluid flow line; a fluid container or ampoule, the ultrasonic waveguide being disposed on or in the fluid container or ampoule and the controller being 1configured to determine, from the detected signals, a fill level and / or a temperature of the fluid container or ampoule; and / or a pedestal for supporting a semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen, the controller being configured to determine, from the detected signals, a temperature of at least a portion of the pedestal; and the controller is configured to determine, from the monitored outputs, a condition of the semiconductor fabrication equipment.

[0126] Implementation 50: The apparatus of implementation 49, wherein the controller is configured to determine, from the monitored outputs, one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity of the reflected ultrasonic signals.

[0127] Implementation 51 : The apparatus of implementation 49 or implementation 50, wherein the semiconductor fabrication equipment includes the pedestal for supporting the semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen and the controller is configured to determine, from the detected signals, temperatures at multiple locations of the pedestal.

[0128] Implementation 52: The apparatus of any one of implementations 49 to 51, wherein the condition comprises one or more of: temperature of the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal.

[0129] Implementation 53: The apparatus of any one of implementations 49 to 52, wherein the condition comprises a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line.

[0130] Implementation 54: The apparatus of any one of implementations 49 to 53, wherein the controller is configured to use, at least, flexural and torsional propagation modes of the reflected ultrasonic signals to determine the temperature of at least the portion of the fluid flow line, the fill level and / or the temperature of the fluid container or ampoule; and / or the temperature of at least the portion of the pedestal.

[0131] Implementation 55: The apparatus of any one of implementations 49 to 54, wherein the controller is configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment.

[0132] Implementation 56: The apparatus of any one of implementations 49 to 55, wherein the controller is configured to monitor outputs of a sensing arrangement repeatedly, at intervals or continuously, so as to provide a substantially closed loop control process.

[0133] Implementation 57: The apparatus of any one of implementations 49 to 56, wherein the controller is configured to make a determination as to whether the monitored outputs are within acceptable limits.

[0134] Implementation 58: The apparatus of any one of implementations 49 to 57, wherein, if the determination indicates the monitored outputs are not within acceptable limits, the controller is configured to sound an alarm, signal an operator, initiate a soft shutdown of the semiconductor fabrication equipment, abort an operation of the semiconductor fabrication equipment, or recommend further analysis and / or corrective action.

[0135] Implementation 59: An apparatus for monitoring semiconductor fabrication equipment, the equipment including a pedestal configured to support a semiconductor substrate and a showerhead, the apparatus comprising: a sensing arrangement comprising at least one waveguide enclosed by a platen disposed on the pedestal; an ultrasonic transducer coupled to the waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals and to determine, from the detected signals, a temperature of at least a portion of the pedestal.

[0136] Implementation 60: The apparatus of implementation 59, wherein the logic is configured to use the time of flight, amplitude, propagation mode and / or wave velocity of the reflected ultrasonic signals to determine the temperature of at least the portion of the pedestal.

[0137] Implementation 61: The apparatus of implementation 59 or implementation 60, wherein the semiconductor substrate is disposed on the platen, between the platen and the showerhead.

[0138] Implementation 62: The apparatus of any one of implementations 59 to 61, wherein the platen comprises an upper plate and a lower plate, and the waveguide is disposed between, and enclosed by, the upper plate and the lower plate.

[0139] Implementation 63: The apparatus of implementation 62, wherein the waveguide is within a groove in an interior surface of at least one of the upper plate and the lower plate.

[0140] Implementation 64: The apparatus of implementation 62, wherein the waveguide comprises a strip having a rectangular cross section.

[0141] Implementation 65: The apparatus of implementation 64, wherein the rectangular cross section has a width and a length, the length being at least five times the width.

[0142] Implementation 66: The apparatus of implementation 64, wherein the waveguide comprises a plurality of straight segments, adjacent straight segments being coupled by folds.

[0143] Implementation 67: The apparatus of any one of implementations 59 to 66, wherein the waveguide has a curvilinear geometry.

[0144] Implementation 68: The apparatus of implementation 67, wherein the waveguide comprises a first unit and a second unit.

[0145] Implementation 69: The apparatus of implementation 68, wherein the first unit comprises a first curved portion and the second unit comprises a second curved portion, the second curved portion being approximately coaxial with the first curved portion.

[0146] Implementation 70: The apparatus of any one of implementations 59 to 69, wherein the controller is configured to determine, from the detected signals, a respective temperature of multiple locations of the pedestal.

Claims

CLAIMSWhat is claimed is:

1. An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising: at least one waveguide configured to contact a liquid in a tool for semiconductor fabrication and an ultrasonic transducer coupled to the waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation modes and wave velocity of the reflected ultrasonic signals to determine one or both of a temperature of the liquid in the tool and a level of the liquid in the tool, wherein the controller is configured to control, based on the monitored outputs, an operational parameter of the semiconductor fabrication equipment.

2. The apparatus of claim 1, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the temperature of the liquid in the tool.

3. The apparatus of claim 1 or claim 2, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the level of the liquid in the tool.

4. The apparatus of claim 1, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the temperature of the liquid in the tool and the level of the liquid in the tool.

5. The apparatus of any one of claims 1 to 4, wherein the logic is configured to use, at least, flexural and torsional propagation modes to determine the temperature and the level of the liquid in the tool.

6. The apparatus of claim 5, wherein the logic is configured to use amplitude and / or time of flight in the flexural propagation mode to determine the level of the liquid in the tool.

7. The apparatus of claim 5, wherein the logic is configured to use amplitude and / or time of flight in the torsional propagation mode to determine the temperature of the liquid.

8. The apparatus of any one of claims 1 to 7, wherein the tool is a container for the liquid.

9. The apparatus of claim 8, wherein the container is an electroplating cell and / or bath.

10. The apparatus of claim 9, wherein the liquid includes one or more of water, a copper sulphate solution, a nickel plating solution, a tin-silver plating solution, a gold plating solution, sulfuric acid, hydrogen peroxide, and / or hydrofluoric acid.

11. The apparatus of claim 8, wherein the container is a cleaning bath.

12. The apparatus of claim 11, wherein the liquid includes one or more of: water, hydrogen peroxide, hydrofluoric acid, and / or sulfuric acid.

13. The apparatus of claim 8, wherein the container is configured as an ampoule for storing liquid deposition precursors.

14. The apparatus of claim 13, wherein the liquid includes one or more of: M0O2CI2, M0CI5, tetraethyl orthosilicate, hexachlorodisilane, and / or triethylphosphate.

15. An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement including: a waveguide disposed within a fluid flow line of the semiconductor fabrication equipment; an ultrasonic transducer, disposed external to the fluid flow line; and a coupling disposed between the ultrasonic transducer and the waveguide; wherein: the ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide; the coupling provides a pneumatic seal configured to prevent leakage of fluid from the fluid flow line; and the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation mode and wave velocity of the reflected ultrasonic signals to determine a plurality of temperatures of a fluid in the fluid flow line at two or more locations along a length of the fluid flow line.

16. The apparatus of claim 15, wherein the logic is configured to use the time of flight, amplitude, and propagation mode of the reflected ultrasonic signals to determine the plurality of temperatures of the fluid.

17. The apparatus of claim 15, wherein the logic is configured to use, at least, flexural and torsional propagation modes to determine the plurality of temperatures.

18. The apparatus of claim 17, wherein the logic is configured to use amplitude and / or time of flight in the torsional propagation mode to determine the plurality of temperatures.

19. The apparatus of claim 15, wherein: the waveguide is configured to avoid interference with flow of the fluid, the waveguide has a long axis generally parallel to the fluid flow line, and wherein dimensions of the waveguide orthogonal to the long axis are substantially less than a diameter of the fluid flow line.

20. An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising: at least one ultrasonic transducer coupled to an exterior surface of a tool containing a fluid, the ultrasonic transducer being configured to transmit ultrasonic signals through the exterior surface and to receive reflected ultrasonic signals from the exterior surface, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use one or more of the time of flight, amplitude, propagation modes and wave velocity of the reflected ultrasonic signals to determine one or both of a temperature of the fluid in the tool and a level of the fluid in the tool.

21. An apparatus for monitoring semiconductor fabrication equipment, the apparatus comprising: a sensing arrangement coupled with the semiconductor fabrication equipment, the sensing arrangement comprising at least one ultrasonic waveguide and an ultrasonic transducer; and a controller configured to monitor outputs of the sensing arrangement, wherein:the ultrasonic transducer is configured to transmit ultrasonic signals onto the waveguide and to detect reflected ultrasonic signals from the waveguide; the monitored outputs of the sensing arrangement include the detected reflected signals; and the semiconductor fabrication equipment includes: a fluid flow line, the ultrasonic waveguide being disposed on or within the fluid flow line and the controller being configured to determine, from the detected signals, temperature of at least a portion of the fluid flow line; a fluid container or ampoule, the ultrasonic waveguide being disposed on or in the fluid container or ampoule and the controller being configured to determine, from the detected signals, a fill level and / or a temperature of the fluid container or ampoule; and / or a pedestal for supporting a semiconductor substrate, the ultrasonic waveguide being disposed between the pedestal and the semiconductor substrate and enclosed by a platen, the controller being configured to determine, from the detected signals, a temperature of at least a portion of the pedestal; and the controller is configured to determine, from the monitored outputs, a condition of the semiconductor fabrication equipment.

22. An apparatus for monitoring semiconductor fabrication equipment, the equipment including a pedestal configured to support a semiconductor substrate and a showerhead, the apparatus comprising: a sensing arrangement comprising at least one waveguide enclosed by a platen disposed on the pedestal; an ultrasonic transducer coupled to the waveguide and configured to transmit ultrasonic signals onto the waveguide and to receive reflected ultrasonic signals from the waveguide, wherein the ultrasonic transducer is further configured to detect, for the reflected ultrasonic signals one or more of: (a) time of flight, (b) amplitude, (c) propagation mode, and (d) wave velocity; and a controller configured to monitor outputs of the sensing arrangement, the controller comprising logic configured to use the time of flight, amplitude, and propagation modes of the reflected ultrasonic signals and to determine, from the detected signals, a temperature of at least a portion of the pedestal.

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