Method and system for precursor level monitoring

Abstract

To provide a method and a system for precursor level monitoring.SOLUTION: A method adopted for determining the amount of a precursor in a precursor vessel; a system related thereto; the precursor vessel; a data processing system; a computer program product; and a computer readable medium are provided. The method comprises performing at least a pressure analysis sequence as the function of time by a processor to quantify the residual quantity of the precursor thereby.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure is in the field of integrated device manufacturing, specifically deposition tools, systems, and processes for integrated circuit manufacturing, and more specifically techniques for determining the amount of a precursor, such as a solid precursor, in a precursor container for semiconductor manufacturing processes. [Background technology]

[0002] With the ever-increasing advancements in semiconductors and semiconductor manufacturing processes, there is a need for greater uniformity and process control during the manufacturing process.

[0003] During processes such as atomic layer deposition (ALD), epitaxy, and chemical vapor deposition (CVD), precursors, which may be in gas, liquid, or solid form, are deposited onto or contact the workpiece. These precursors are often stored in a precursor container or vessel from which they are transported to the workpiece in a reaction chamber.

[0004] While a process is being performed, it may be advantageous to monitor the amount of precursor in the precursor vessel to prevent production defects due to depletion of the precursor material. The ability to monitor the remaining amount of precursor material in the precursor vessel is important to ensure process quality, enable efficient scheduling of precursor vessel changes, maximize the use of expensive chemicals, and improve inventory management.

[0005] While level sensing is an industry standard for gaseous or liquid materials, monitoring the remaining amount of solid precursor materials is more complicated. Typically, precursor materials are transported from a precursor container to a reactor chamber by flowing a carrier gas through the precursor container, thereby generating a process gas that includes the carrier gas and vaporized solid precursor, which is then provided to the process chamber. Some of the process conditions employed in manufacturing processes (e.g., a range of high temperatures, the use of carrier gas, etc.) result in precursor level monitoring being difficult for existing level sensing systems, especially when resolution and accuracy are important.

[0006] Therefore, a need exists for an improved method and apparatus for monitoring the amount of solid precursor in a precursor container for a semiconductor manufacturing process. Summary of the Invention [Means for solving the problem]

[0007] A method is described herein that includes providing a plurality of precursor pulses from a precursor container to a precursor line in fluid connection with the precursor container. The precursor container can include a precursor. The method can include sensing, by a pressure gauge, a pressure as a function of time that includes the plurality of pressure pulses. The method can further include performing, by a processor, an analysis sequence of at least the pressure as a function of time, thereby quantifying a remaining amount of the precursor. The method can further include comparing the remaining amount of the precursor to a predetermined precursor amount. If the remaining amount of the precursor exceeds the predetermined precursor amount, a sufficient precursor signal can be generated. If the remaining amount of the precursor is at most equal to the predetermined precursor amount, an insufficient precursor signal can be generated.

[0008] Further described herein is a system comprising a precursor container connector constructed and arranged for operatively connecting to a precursor container containing a precursor, e.g., a solid precursor. The reaction chamber can be fluidly connected to the precursor container via a precursor line. The reaction chamber can be constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line. The system can further comprise a pressure gauge constructed and arranged to sense pressure as a function of time. The pressure as a function of time can include a plurality of pressure pulses. The system can further comprise a processor. The processor can be constructed and arranged to perform an analysis sequence including at least analyzing the pressure as a function of time, thereby quantifying the remaining amount of precursor, comparing the remaining amount of precursor to a predetermined precursor amount, and comparing the remaining amount of precursor to the predetermined precursor amount. If the remaining amount of precursor exceeds the predetermined precursor amount, the processor can generate a sufficient precursor signal. If the remaining amount of precursor is at most equal to the predetermined precursor amount, the processor can generate an insufficient precursor signal.

[0009] In some embodiments, the precursor is in a solid state.

[0010] In some embodiments, the precursor comprises a metal center and one or more ligands.

[0011] In some embodiments, a pulse from the plurality of pulses includes at least one of a leading edge portion, a holding edge portion, and a decay portion, and the remaining amount of precursor can be determined by analyzing one or more of the leading edge portion, the holding edge portion, and the decay portion.

[0012] In some embodiments, the rising portion comprises a straight segment. In such embodiments, the remaining amount of precursor can be quantified as being extremely low.

[0013] In some embodiments, the pressure gauge is positioned within the precursor container.

[0014] In some embodiments, the leading edge includes a saturated segment and the remaining amount of precursor is quantified as being sufficient, hi some embodiments, the saturated segment of the leading edge can be considered or modeled as a retention portion.

[0015] In some embodiments, if a sufficient precursor signal is generated, a cyclic deposition process can be performed using precursors in a reaction chamber that is in fluid connection with a precursor container via a precursor line.

[0016] In some embodiments, when an insufficient precursor signal is generated, the insufficient precursor signal prevents the system from performing a cyclic deposition process using a precursor in a reaction chamber that is in fluid connection with a precursor container via a precursor line.

[0017] In some embodiments, the remaining amount of precursor is determined by analyzing the rising portion. Analyzing the rising portion can include fitting the rising portion using a function selected from an exponential function, a four-parameter logistic function, and an Arrhenius function.

[0018] In some embodiments, the exponential function is a three-parameter exponential function of the form P(t)=AB*exp(-Ct), where A, B, and C can be positive real numbers.

[0019] In some embodiments, the precursor container further comprises a constructed capacitance sensor. The precursor container can be arranged to measure a sensed capacitance. The analysis sequence can include determining a remaining amount of precursor based on the sensed capacitance in addition to the pressure as a function of time.

[0020] In some embodiments, the analysis sequence includes determining a capacitance-derived amount of precursor remaining based on the sensed capacitance; determining a pressure-derived amount of precursor remaining based on the pressure as a function of time; comparing the capacitance-derived amount of precursor remaining to the pressure-derived amount of precursor remaining; and quantifying the amount of precursor remaining if the capacitance-derived amount of precursor remaining and the pressure-derived amount of precursor remaining are equal within a predetermined error limit, setting the amount of precursor remaining equal to the capacitance-derived amount of precursor remaining, equal to the pressure-derived amount of precursor remaining, or equal to an interpolated value thereof; and generating an error signal otherwise.

[0021] Further described herein is a precursor container comprising a precursor, a pressure gauge, and a capacitance sensor. The precursor container can be fluidly connectable to a reaction chamber via a precursor line. The reaction chamber and the precursor line can be comprised in a deposition system. The reaction chamber can be constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line. The pressure gauge can be constructed and arranged to sense a pressure as a function of time, the pressure as a function of time comprising a plurality of pressure pulses. The capacitance sensor can be constructed and arranged to measure a sensed capacitance. The precursor container can be operatively connectable to a processor comprised in the deposition system, the processor constructed and arranged to perform an analysis sequence including analyzing one or both of the pressure as a function of time and the sensed capacitance to thereby quantify a remaining amount of precursor, comparing the remaining amount of precursor to a predetermined precursor amount, generating a sufficient precursor signal if the remaining amount of precursor exceeds the predetermined precursor amount, and generating an insufficient precursor signal if the remaining amount of precursor is at most equal to the predetermined precursor amount.

[0022] In some embodiments, the precursor comprises a solid precursor.

[0023] In some embodiments, the precursor comprises a center and one or more ligands, wherein the center is selected from transition metals, post-transition metals, lanthanides, and metalloids, and the one or more ligands are independently selected from the list consisting of arenes, halides, alkyls, cyclopentadienyls, amides, chelating nitrogen-containing ligands, alkoxides, beta-diketonates, and carbonyls.

[0024] Further described herein is a data processing unit comprising a receiving unit constructed and arranged to receive pressure as a function of time, including a plurality of pressure pulses, an analysis unit constructed and arranged to perform at least an analysis sequence of the pressure as a function of time, thereby quantifying a remaining amount of precursor, a comparison unit constructed and arranged to compare the remaining amount of precursor with a predetermined precursor amount, and a generation unit constructed and arranged to generate a sufficient precursor signal when the remaining amount of precursor exceeds the predetermined precursor amount, and a generation unit further constructed and arranged to generate an insufficient precursor signal when the remaining amount of precursor is at most equal to the predetermined precursor amount.

[0025] Further described herein is a computer program product comprising instructions to cause a data processing unit as described herein to perform the steps of the methods as described herein.

[0026] Further described herein is a computer readable medium having stored thereon a computer program product as described herein.

[0027] This Summary is provided to introduce selected concepts in a simplified form. These concepts are described in more detail in the Detailed Description of Example Embodiments of the Disclosure below. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 illustrates one embodiment of a processing system 100 . [Figure 2A] FIG. 2A illustrates an embodiment of a subsystem 200 . [Figure 2B] FIG. 2B illustrates an embodiment of subsystem 200. [Diagram 3] FIG. 3 shows an example of pressure development as a function of time for a full container. [Figure 4A] FIG. 4A shows a stylized pressure versus time curve 400 of an embodiment of a precursor pulse. [Figure 4B] FIG. 4B shows a stylized pressure versus time curve 400 of an embodiment of a precursor pulse. [Figure 4C] FIG. 4C shows a stylized pressure versus time curve 400 of an embodiment of a precursor pulse. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] It will be appreciated that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale, for example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the illustrated embodiments of the present disclosure.

[0030] Although certain specific embodiments and examples are disclosed below, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention, and obvious modifications and equivalents thereof, and therefore it is not intended that the scope of the disclosed invention should be limited by the specific disclosed embodiments described below.

[0031] The term "substrate" as used herein may refer to any underlying material or materials, including any underlying material or materials on which a device, circuit, or film may be formed. A "substrate" may be continuous or non-continuous, rigid or flexible, solid or porous, and combinations thereof. The substrate may be in any form, such as a powder, plate, or workpiece. Substrates in the form of plates may include wafers of various shapes and sizes. Substrates may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0032] As an example, the substrate in the form of a powder may have applications for pharmaceutical manufacturing. The porous substrate may include a polymer. Examples of workpieces may include medical devices (e.g., stents and syringes), jewelry, tooling devices, components for battery manufacturing (e.g., anodes, cathodes, or separators), or components of photovoltaic cells, etc.

[0033] The continuous substrate may extend beyond the boundaries of the process chamber in which the deposition process occurs. In some processes, the continuous substrate may move through the process chamber, such that the process continues until the end of the substrate is reached. The continuous substrate may be fed from a continuous substrate feeding system to enable the production and output of the continuous substrate in any suitable form.

[0034] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, webs, flexible materials, bundles of continuous filaments or fibers (e.g., ceramic or polymeric fibers). Continuous substrates may also include carriers or sheets onto which the non-continuous substrates are placed.

[0035] As used herein, the term "deposition process" can refer to the introduction of precursors (and / or reactants) into a reaction chamber to deposit a layer over a substrate. A "cyclic deposition process" is an example of a "deposition process."

[0036] The term "cyclic deposition process" or "cyclical deposition process" can refer to the sequential introduction of precursors (and / or reactants) into a reaction chamber to deposit layers on a substrate, and includes processing techniques such as atomic layer deposition (ALD), cyclic chemical vapor deposition (cyclic CVD), and hybrid cyclic deposition processes that include ALD and cyclical CVD components.

[0037] The term "atomic layer deposition" can refer to a deposition process in which deposition cycles, typically multiple successive deposition cycles, are performed in a process chamber. As used herein, the term atomic layer deposition is also meant to include processes designated by related terms such as atomic layer chemical vapor deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, metalorganic MBE, and chemical beam epitaxy, when performed with alternating pulses of precursor / reactive gases and purge (e.g., inert carrier) gas. Pulsing can include exposing the substrate to a precursor or reactant. This can be done, for example, by introducing the precursor or reactant into a reaction chamber in which the substrate is present. Additionally or alternatively, exposing the substrate to the precursor can include moving the substrate to a location in the substrate processing system where the reactant or precursor is present.

[0038] Generally, for an ALD process, during each cycle, a precursor is introduced into the reaction chamber and chemisorbed onto the deposition surface (e.g., a substrate surface, which may include previously deposited material or other materials from a previous ALD cycle) and forms a monolayer or quasi-monolayer of material that does not readily react with additional precursors (i.e., self-limiting reaction). A reactant (e.g., another precursor or reactant gas) may then be introduced into the process chamber for use in converting the chemisorbed precursor to a desired material on the deposition surface. The reactant may be capable of further reaction with the precursor. Purging steps may be utilized during one or more cycles (e.g., during each step of each cycle) to remove any excess precursor from the process chamber and / or to remove any excess reactants and / or reaction by-products from the reaction chamber.

[0039] As used herein, the term "purging" may refer to a procedure in which an inert gas or a substantially inert gas is provided to a reaction chamber between two pulses of gases that react with each other. For example, a purge using, for example, a noble gas may be provided between a precursor pulse and a reactant pulse, thus avoiding or at least minimizing gas phase interactions between the precursor and the reactant. In some embodiments, "purging" may refer to a procedure in which a reactive purge gas is provided to a reaction chamber between pulses of two gases that react with each other and with the purge gas.

[0040] Of course, purging and pulsing can be accomplished either temporally or spatially or both. For example, in the case of temporal purging, the purging step can be used in a time sequence, for example, by providing a first precursor to the reaction chamber, providing a purge gas to the reaction chamber, and providing a second precursor to the reaction chamber, without moving the substrate on which the layer is deposited. For example, in the case of spatial purging, the purging step can take the following form: moving the substrate from a first location where the first precursor is continuously provided, through a purge gas curtain, to a second location where the second precursor is continuously provided. For example, in the case of temporal pulsing, the precursor can be provided for a predetermined length of time before and after which an inert gas is provided to the reaction chamber. For example, in the case of spatial pulsing, the substrate can be moved through a predetermined location where the precursor is provided and surrounded by one or more inert purge gas curtains.

[0041] As used herein, "precursor" includes a gas or material that can be gaseous and can be represented by a chemical formula that includes elements that may be incorporated during a deposition process as described herein.

[0042] The illustrations presented herein are not meant to be actual representations of any particular materials, structures, or devices, but merely idealized representations used to describe embodiments of the present disclosure.

[0043] The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of aspects and implementations in any way. Indeed, for the sake of brevity, conventional manufacturing, association, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent example functional relationships and / or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in an actual system and / or may not be present in some embodiments.

[0044] It should be understood that the configurations and / or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be construed in a limiting sense, as numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various illustrated operations may be performed in the order illustrated, in other orders, or omitted in some cases.

[0045] Described herein are methods, systems, computer program products, precursor containers, and computer readable media that allow for determining the amount of precursor contained within a precursor container while it is in use. Such information can be highly advantageous for preventing process failures related to precursor depletion.

[0046] In some embodiments of the method as described herein, multiple precursor pulses are provided from a precursor container to a precursor line in fluid connection with the precursor container. The precursor container can be completely full or partially empty. In other words, the precursor container can contain precursor. For example, the precursor container can be filled with 100%, 90%, 80%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or 5% precursor. Of course, these percentages can be conveniently expressed as mass percentages, i.e., as the "mass of the amount of precursor remaining in the precursor container" divided by the "mass of precursor in the precursor container when the precursor container is full."

[0047] During normal operation of a pulsed deposition process, such as an atomic layer deposition process, the valves can be operated sequentially to provide a precursor from a precursor container to a reaction chamber in multiple pulses. For example, the following sequence, including two alternating steps a) and b), can be used, for example, for a solid precursor: a) the container valve is closed, no precursor is provided from the precursor container, and as the precursor sublimes, the precursor in the container asymptotically rises to the vapor pressure of the precursor; b) the container valve is opened, the precursor is provided from the precursor container, and the pressure in the precursor container decreases. The inventors have surprisingly discovered that at least one of the resulting pressure increase and pressure decrease can be used to characterize the amount of remaining precursor in the precursor container.

[0048] Therefore, embodiments of the methods described herein can include sensing the pressure as a function of time, including multiple pressure pulses, by a pressure gauge. In some embodiments, these pressure increases can be measured by a pressure gauge positioned in the precursor container. In some embodiments, the pressure decreases can be measured by a pressure gauge positioned in the precursor container or by a pressure gauge positioned in the precursor line downstream of the precursor container and upstream of the reaction chamber.

[0049] An embodiment of the method described herein can include performing, by a processor, an analysis sequence of at least pressure as a function of time, so that the remaining amount of precursor can be quantified.

[0050] Embodiments of the methods described herein can include comparing a remaining amount of the precursor to a predetermined precursor amount. If the remaining amount of the precursor exceeds the predetermined precursor amount, a sufficient precursor signal can be generated. On the other hand, if the remaining amount of the precursor is at most equal to the predetermined precursor amount, an insufficient precursor signal can be generated. In some embodiments, a sufficient precursor signal can cause a deposition process employing the precursor to run. In some embodiments, an insufficient precursor signal can prevent a deposition process employing the precursor from running.

[0051] In some embodiments, a method as disclosed herein can include obtaining a first predetermined amount of precursor at a first time and obtaining a second predetermined amount of precursor at a second time. In such embodiments, a rate of precursor consumption can be obtained from the first predetermined amount of precursor, the second predetermined amount of precursor, the first time, and the second time. In some embodiments, the rate of precursor consumption is equal to the precursor difference divided by the time difference, where the precursor difference is equal to the second predetermined amount of precursor minus the first predetermined amount of precursor, and the time difference is equal to the second time minus the first time.

[0052] In some embodiments, methods as described herein can include generating an excess precursor consumption signal when a rate of precursor consumption exceeds a predetermined amount of precursor. When an excess precursor consumption signal is generated, a deposition process employing the precursor in question can be automatically terminated, for example, by stopping the flow of the precursor.

[0053] In some embodiments, pressure measurements can be employed to derive the dose during a pulse, for example during a single pulse. The dose can refer to the total amount of precursor drawn from the precursor container during a single pulse. In some embodiments, the dose can be measured using a pressure gauge located inside the precursor container. In some embodiments, the precursor container is closed, i.e., its inlet and outlet valves are closed between two subsequent pulses, between the previous pulse and the next pulse. In such an embodiment, the dose can be determined by a pressure measurement immediately after the previous pulse and a pressure measurement immediately before the next pulse. The amount of additional molecules in the gas phase immediately before the next pulse compared to immediately after the previous pulse is equal to the dose. This amount can be easily derived using gas laws such as the ideal gas law or the real gas law (van der Waals).

[0054] In some embodiments, a precursor container as described herein contains a precursor in solid form, i.e., a solid precursor.

[0055] The dose is seen just before the container inlet and / or outlet valve is opened. This comes from the build-up that takes place during which the valve is closed and the containers are separated.

[0056] Systems are further described herein. In some embodiments, the systems can be constructed and arranged to perform cyclical vapor deposition methods, such as atomic layer deposition. In some embodiments, the systems are constructed and arranged to perform methods as described herein.

[0057] A system as described herein can include a precursor container connector constructed and arranged to operatively connect to a precursor container. The precursor container includes a precursor. In some embodiments, the precursor container is included within the system.

[0058] The system may further include a reaction chamber in fluid communication with the precursor container via the precursor line. The reaction chamber may be constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line.

[0059] The system may further comprise a pressure gauge constructed and arranged to sense the pressure as a function of time. The pressure as a function of time may include a plurality of pressure pulses.

[0060] The system may further comprise a processor. The processor may be constructed and arranged to perform an analysis sequence including analyzing at least the pressure as a function of time, thereby quantifying the remaining amount of precursor. The analysis sequence may further include comparing the remaining amount of precursor to a predetermined precursor amount. The analysis sequence may further include comparing the remaining amount of precursor to a predetermined precursor amount. If the remaining amount of precursor exceeds the predetermined precursor amount, the processor may generate a sufficient precursor signal. If the remaining amount of precursor is at most equal to the predetermined precursor amount, the processor may generate an insufficient precursor signal.

[0061] FIG. 1 shows an embodiment of a processing system 100 comprising one or more process chambers 102, a precursor gas source 104, a gas source 105, a reactant gas source 106, a purge gas source 108, an exhaust 110, and a process control unit 112.

[0062] The process chamber 102 may include any suitable process chamber, such as an atomic layer deposition (ALD) or chemical vapor deposition (CVD) reaction chamber.

[0063] The precursor gas source 104 can include a precursor container and one or more precursors as described herein, either alone or mixed with one or more carrier gases (e.g., noble gases). Preferably, at least one precursor container is equipped with a capacitance sensor system as described herein.

[0064] The reactant gas source 106 can include a container and one or more reactants as described herein, either alone or mixed with one or more carrier gases. The purge gas source 108 can include one or more noble gases (such as He, Ne, Ar, Kr, and / or Xe). Although illustrated with four gas sources 104-108, the system 100 can include any suitable number of gas sources. The gas sources 104-108 can be coupled to the process chamber 102 via lines 114-118, which can each include flow controllers, valves, heaters, and the like. At least one of the gas sources includes at least one of pressure-based and capacitance-based precursor level sensing mechanisms as disclosed herein.

[0065] The exhaust 110 may include one or more vacuum pumps.

[0066] The process control unit 112 includes electronic circuitry and software for selectively operating the valves, manifolds, heaters, pumps, and other components included within the reactor system 100. Such circuitry and components operate to introduce precursor and purge gases from their respective sources 104-108. The process control unit 112 can control the timing of gas pulse sequences, the temperature of the substrate and / or the process chamber, the pressure within the process chamber, and various other operations to provide proper operation of the system 100. The process control unit 112 can include control software for controlling valves, either electrically or pneumatically, to control the flow of precursor, reactant, and purge gases into and out of the process chamber 102. The process control unit 112 can include software or hardware components, such as modules, e.g., FPGAs or ASICs, that perform certain tasks. The modules can be advantageously configured to reside on addressable storage media of the control system and can be configured to perform one or more processes.

[0067] Other configurations of the system 100 are possible, including different numbers and types of precursor and reactant sources, and purge gas sources. Additionally, it will be appreciated that there are numerous arrangements of valves, conduits, precursor sources, and purge gas sources that may be used to achieve the goal of selectively feeding gases into the process chamber 202. Additionally, as a schematic representation of the system, many components have been omitted for simplicity of illustration, and such components may include, for example, various valves, manifolds, purifiers, heaters, vessels, vents, and / or bypasses.

[0068] During operation of the reactor system 100, a substrate (not shown), such as a semiconductor wafer, is transferred, for example, from a substrate handling system to the process chamber 102. Once the substrate is transferred to the process chamber 102, one or more gases (e.g., precursor, reactant, carrier gases, and / or purge gases) from gas sources 104-108 are introduced into the process chamber 102.

[0069] Further described herein is a precursor container comprising a precursor, a pressure gauge, and a capacitance sensor. The precursor container can be fluidly connected and connectable to a reaction chamber via a precursor line. The reaction chamber and the precursor line can be included in a deposition system. The reaction chamber can be constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line. The pressure gauge can be constructed and arranged to sense pressure as a function of time. The pressure as a function of time can include a plurality of pressure pulses. The capacitance sensor is constructed and arranged to measure the sensed capacitance. The sensed capacitance can indicate a remaining amount of precursor. Additionally, the precursor container can be operatively connectable to a processor included in the deposition system. The processor can be constructed and arranged to perform an analysis sequence that includes analyzing one or both of the pressure and the sensed capacitance as a function of time. Thus, the remaining amount of precursor can be quantified. The processor can be further constructed and arranged to compare the remaining amount of precursor to a predetermined precursor amount. The processor may be further constructed and arranged to generate a sufficient precursor signal when the remaining amount of precursor exceeds a predetermined precursor amount. The processor may be further constructed and arranged to generate an insufficient precursor signal when the remaining amount of precursor is at most equal to the predetermined precursor amount.

[0070] The data processing unit is further described herein. The data processing unit may include a processor in some embodiments. The data processing unit may include a receiving unit constructed and arranged to receive the pressure as a function of time. The pressure as a function of time includes a plurality of pressure pulses. The data processing unit may further include an analysis unit. The analysis unit may be constructed and arranged to perform an analysis sequence of at least the pressure as a function of time. Thus, the remaining amount of the precursor may be quantified. The analysis unit may further include a comparison unit further constructed and arranged to compare the remaining amount of the precursor with a predetermined precursor amount. The analysis unit may further include a generation unit. The generation unit may be constructed and arranged to generate a sufficient precursor signal when the remaining amount of the precursor exceeds the predetermined precursor amount. The generation unit may be further constructed and arranged to generate an insufficient precursor signal when the remaining amount of the precursor is at most equal to the predetermined precursor amount.

[0071] Further described herein is a computer program product comprising instructions to cause a data processing unit as described herein to perform the steps of the methods according to embodiments of the present disclosure.

[0072] A computer readable medium having stored thereon a computer program product according to the present disclosure is further described herein.

[0073] In some embodiments according to the present disclosure, the precursor can be in a solid state, in other words, and in some embodiments, the precursor can be, consist essentially of, or include a solid precursor.

[0074] In some embodiments, the precursor comprises a precursor center and one or more ligands. The precursor center can comprise, for example, a metal center or a metalloid center. Examples of metal centers include transition metal centers, alkali metal centers, alkaline earth metal centers, post-transition metal centers, and rare earth metal centers. Suitable metal centers include aluminum, indium, and tin. Suitable metalloid centers include silicon and germanium. Suitable rare earth metal centers include lanthanides such as lanthanum.

[0075] In some embodiments, the one or more ligands are independently selected from the list consisting of arenes, halides, alkyls, cyclopentadienyls, amides, chelating nitrogen-containing ligands, alkoxides, beta-diketonates, and carbonyls. For example, suitable metal bisarenes include M(Bz)2 and M(RBz)2, where M is a transition metal, Bz is a benzene ring, and R is a C1-C3 alkyl substituent on the benzene ring, such as Ru(Cp)2, where Cp is cyclopentadienyl. Suitable transition metals include tungsten, molybdenum, and ruthenium. Suitable transition metal halides include MoCl5 and HfCl4. For example, suitable transition metal beta-diketonates include W(thd)3, where thd represents 2,2,6,6-tetramethyl-3,5-heptanedione.

[0076] Suitable precursors are described, for example, in “Barry, Sean Thomas, Peter George Gordon, and Vincent Vandalon. “Common Precursors and Surface Mechanisms for Atomic Layer Deposition.” Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2022.” (incorporated by reference in its entirety).

[0077] Further reference is made to Figures 2A and 2B, which show an embodiment of a subsystem 200 comprising a precursor container 210, a precursor line 220, and pressure gauges 215, 225. In the embodiment of Figure 2A, the pressure gauge 215 is mounted within the precursor container 210. In the embodiment of Figure 2B, the pressure gauge 225 is mounted within the precursor line 220.

[0078] Referring now to the embodiment of FIG. 2A, in some embodiments of the present disclosure, a pressure gauge 215 is provided within the precursor container 210. The pressure gauge 215 can monitor the container pressure increase characteristics when the precursor container 210 is isolated from the rest of the system in which the pressure container 210 is embedded. Specifically, during a single ALD cycle, the precursor container can be open only for a short period of time, and all container valves (not shown) can be closed most of the time during the cycle. When the container valves are closed, precursor vapor is generated inside the container, and the pressure within the container gradually increases. The rate and overall shape of this pressure increase can be used to characterize the remaining amount of precursor, in embodiments of the present disclosure.

[0079] Specifically, the vapor generation and subsequent pressure increase (rate and non-linearity) may depend on the amount of precursor available in the vessel. When the vessel is empty, there is no pressure increase from precursor vapor generation. In the nearly empty state, the pressure increase may be linear in appearance. When the vessel is full, the pressure increase curve may be a saturated curve with an initial linear region followed by a slow, gradually slowing increase caused by the vapor pressure reaching saturation. This behavior may be modeled (for example) with a three-parameter exponential function, the curve having a linear increase and the curvature limited by an asymptote. The curve shape may be represented by a slope with the correct coefficients, which means that the vapor generation phenomenon may be correctly modeled (within reasonable time limits) using the chosen slope function, which may lead to the actual precursor amount being correlated with the slope coefficient. Additionally or alternatively, other slope functions may be employed to fit the pressure curve, such as four-parameter logistic, and Arrhenius-type equations.

[0080] An example of pressure development as a function of time for a full vessel is shown in Figure 3, where time is given in seconds and pressure is given in Torr. The pressure as a function of time was fitted using a three exponential function of the form P(t) = A-Bexp(-Ct), where A is 5.94, B is 6.3, and C is 0.24.

[0081] In some embodiments of the pressure disclosure, a pressure gauge is provided in the precursor line downstream of the precursor container and upstream of the reaction chamber. Advantageously, however, the pressure gauge is located in the precursor container. Mounting the pressure gauge in the precursor container can provide more accurate measurements compared to when the precursor container is mounted in the precursor line.

[0082] 4A, which illustrates a stylized pressure versus time curve 400 of an embodiment of a precursor pulse from multiple pulses includes at least one of a leading edge portion 410, a holding edge portion 420, and a decaying edge portion 430. As a result, the remaining amount of precursor can be determined by analyzing one or more of the leading edge portion 410, the holding edge portion 420, and the decaying edge portion 430. In some embodiments, and referring to FIG. 4B, which illustrates another embodiment of a stylized pressure versus time curve 400 from multiple pulses, the leading edge portion 410 and the decaying edge portion 430 can be determined.

[0083] In some embodiments, the remaining amount of precursor is quantified based on rising portion 410.

[0084] In some embodiments, the rising portion 410 includes a straight segment and the amount of precursor remaining is quantified as very low. For example, "very low" can mean that the precursor container is empty or nearly empty, e.g., "nearly empty" can mean that the precursor container is 20% full or less, or 15% full or less, or 10% full or less, or 5% full or less.

[0085] Determining when the leading edge 410 contains a straight segment or a saturated segment can be accomplished using statistical methods. For example, saturation or curvature may be tested by starting with the hypothesis "the leading edge is straight" which should be an incorrect assumption if the leading edge contains a saturated segment, and performing a linear fit to the leading edge. If the R-squared of the linear fit is higher than 0.95 (95%), then one cannot prove oneself wrong and must accept the conclusion that the leading edge contains a straight segment. If the R-squared is less than 0.95, one cannot say with certainty that the line is straight and indicates the alternative conclusion, i.e., that the leading edge contains a saturated segment.

[0086] In some embodiments, the rising portion 410 includes a saturated segment. In such cases, the remaining amount of precursor can be quantified as being sufficient. A rising portion 410 including a saturated segment is shown in Figures 4B and 4C.

[0087] In some embodiments, the measured pressure may increase during the riser portion 410, as shown in Figures 4A and 4B. This may occur, for example, when a pressure gauge is installed in the precursor line.

[0088] In some embodiments, the measured pressure may decrease during the ramp-up portion, as shown in Figure 4C. This may occur, for example, when a pressure gauge is mounted inside the precursor container.

[0089] In some embodiments, the remaining amount of the precursor is determined by analyzing the rising portion. Analyzing the rising portion can include fitting the rising portion using a function. The function can be selected from, for example, an exponential function, a four-parameter logistic function, and an Arrhenius function.

[0090] In some embodiments, the logistic function is a four-parameter function of the form F(x)=D+(A-D) / (1+(x / C)^B, where A, B, C, and D are real numbers, e.g., positive real numbers or negative real numbers.

[0091] In some embodiments, the exponential function is a three-parameter exponential function of the form P(t)=A-Bexp(-Ct), where A, B, and C are real numbers, e.g., positive real numbers or negative real numbers. Such a form can arise when a pressure gauge 225 is installed in the precursor line 220, as shown in FIG. 2B.

[0092] In some embodiments, the exponential function is a three-parameter exponential function of the form P(t)=A+Bexp(-Ct), where A, B, and C are real numbers, e.g., positive real numbers or negative real numbers. Such a form can arise when a pressure gauge 215 is mounted within the precursor container 210, as shown in FIG. 2A.

[0093] In some embodiments, a cyclic deposition process can be performed using precursors in a reaction chamber that is in fluid communication with a precursor container via a precursor line, particularly when a sufficient precursor signal is generated, and therefore a cyclic deposition process can be performed.

[0094] In some embodiments, when an insufficient precursor signal is generated, the insufficient precursor signal prevents the system from performing a cyclic deposition process using a precursor in a reaction chamber that is in fluid connection with a precursor container via a precursor line.

[0095] Providing a pressure-based precursor level measurement according to the present disclosure allows one to measure the remaining amount of precursor and thereby answer the question of when the container needs to be refilled. Nevertheless, any one measurement method is not necessarily infallible and precursor level measurements can be erroneous. Indeed, if one can measure the amount of material in a precursor container, it is still not guaranteed that the chemical will remain intact or behave as intended. Therefore, it can be useful to add redundancy to the precursor level measurement and install additional precursor level sensors. For example, a capacitance precursor level sensor can be employed in addition to a pressure-based precursor level sensor. Indeed, both sensor types may be used in the system to provide a comprehensive picture of what is going on inside the precursor container. The advantage here is to have two types of independent observations that are looking at similar things but based on different phenomena. When the sensor data are aligned, it indicates a stable operating regime of the container. However, when the data do not match, it provides valuable information regarding stability, potential sources of instability, and improved prediction of source outages. In some embodiments, a precursor level determination based on both capacitance and pressure data can be more accurate than a precursor level determination based on one type of data alone.

[0096] Therefore, in some embodiments, the precursor container further comprises a capacitance sensor constructed and arranged to measure the sensed capacitance, In such embodiments, the analysis sequence can include determining the remaining amount of precursor based on the sensed capacitance in addition to the pressure as a function of time.

[0097] A suitable capacitive sensor is described in US Provisional Patent Application No. 63 / 369,695, which is incorporated herein by reference in its entirety.

[0098] In some embodiments, the analysis sequence can include determining a capacitance-derived amount of precursor remaining based on the sensed capacitance. Also, a pressure-derived amount of precursor remaining can be determined based on pressure as a function of time. The capacitance-derived amount of precursor remaining and the pressure-derived amount of precursor remaining can then be compared. Equality of these parameters within a predetermined error range can indicate proper operation. Conversely, non-equality of these parameters within a predetermined error range can indicate the occurrence of an error in the precursor level measurement. In some embodiments, the system can prevent processing of the substrate if the capacitance-derived amount of precursor remaining and the pressure-derived amount of precursor remaining are not equal within a predetermined error range.

[0099] Thus, if the capacitance-derived and pressure-derived remaining amounts of precursor are within a predetermined error limit, such as 10%, 5%, 2%, 1%, or 0.1%, which may indicate a correctly measured amount of precursor remaining, quantifying the amount of precursor remaining includes setting the amount of precursor remaining equal to the capacitance-derived and pressure-derived remaining amounts of precursor, or an interpolated value thereof. The interpolated value may refer to, for example, an average, weighted average, or mean value of the pressure-derived and capacitance-derived remaining amounts of precursor. Otherwise, i.e., if the capacitance-derived and pressure-derived remaining amounts of precursor are not equal within the predetermined error limit, an error signal may be generated.

[0100] In some embodiments, pressure measurement and capacitance measurement are employed to derive precursor stability.Indeed, when capacitance precursor level measurement indicates a substantially higher filling level than pressure measurement, for example, when capacitance-derived precursor level is 10%, 20%, 30%, or 40% higher than pressure-derived precursor level, the precursor can be determined to be unstable.For example, when capacitance measurement indicates a 50% filling level and pressure measurement indicates a 10% filling level, it can be inferred that the precursor is at least partially decomposed, i.e., the precursor can be estimated to be unstable.

[0101] In some embodiments, pressure and capacitance measurements are employed to derive the fill level and expected depletion. In fact, these two different sensing mechanisms can be used in concert to obtain a robust estimate of the fill level and consumption rate (including loss of precursors via degradation and the like). With an estimate of the precursor "loss rate," refills (and back-up tools during production) can be estimated and scheduled with a reasonably high level of confidence.

[0102] The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various processes, systems, and configurations, and other features, functions, operations and / or properties disclosed herein, as well as all equivalents thereof. [Explanation of symbols]

[0103] 100 Processing Systems 102 Process chamber 104 Precursor Gas Source 105 Gas Source 106 Reactant Gas Source 108 Purge gas source 110 Exhaust 112 Process Control Unit 114, 115, 116, 118 lines 200 Subsystems 210 Precursor Container 220 Precursor Line 215, 225 Pressure Gauge 400 Pressure vs. Time Curve 410 Rising part 420 Holding part 430 Attenuation part

Claims

1. 1. A method comprising: - providing a plurality of precursor pulses from a precursor container to a precursor line in fluid connection with said precursor container, said precursor container comprising a precursor; - sensing pressure as a function of time, including a plurality of pressure pulses, by a pressure gauge; - carrying out, by a processor, a sequence of analyses of at least the pressure as a function of time, thereby quantifying the remaining amount of precursor; - comparing said remaining amount of said precursor with a predetermined precursor amount; - generating a sufficient precursor signal when the remaining amount of the precursor exceeds the predetermined precursor amount; or generating an insufficient precursor signal when the remaining amount of the precursor is at most equal to the predetermined precursor amount.

2. The method of claim 1 , wherein the precursor is in a solid state.

3. The method of claim 1 or 2, wherein the precursor comprises a metal center and one or more ligands.

4. 3. The method of claim 1 or 2, wherein the precursor pulse from the multiple precursor pulses includes at least one of a leading edge portion, a hold portion, and a decay portion, and the remaining amount of the precursor is determined by analyzing one or more of the leading edge portion, the hold portion, and the decay portion.

5. The method of claim 4 , wherein the raised portion comprises a straight segment and the remaining amount of the precursor is quantified as being very low.

6. The method of claim 5 , wherein the pressure gauge is positioned within the precursor vessel.

7. The method of claim 4 , wherein the leading edge includes a saturated segment and the remaining amount of the precursor is quantified as sufficient.

8. 3. The method of claim 1 or 2, wherein when the sufficient precursor signal is generated, a cyclic deposition process is performed using the precursor in a reaction chamber in fluid communication with the precursor container via the precursor line.

9. 3. The method of claim 1 or 2, wherein when the insufficient precursor signal is generated, the insufficient precursor signal prevents the system from performing a cyclic deposition process using the precursor in a reaction chamber that is in fluid connection with the precursor container via the precursor line.

10. 5. The method of claim 4, wherein the remaining amount of the precursor is determined by analyzing the leading edge, and analyzing the leading edge comprises fitting the leading edge using a function selected from an exponential function, a four-parameter logistic function, and an Arrhenius function.

11. 11. The method or system of claim 10, wherein the exponential function is a three-parameter exponential function of the form P(t)=A-Bexp(-Ct), where A, B, and C are positive real numbers.

12. 3. The method of claim 1 or 2, wherein the precursor container further comprises a capacitance sensor constructed and arranged to measure a sensed capacitance, and the analysis sequence includes determining the remaining amount of the precursor based on the sensed capacitance in addition to the pressure as a function of time.

13. The analysis sequence comprises: - determining a remaining amount of the precursor from the capacitance based on the sensed capacitance; - determining a remaining amount of said precursor resulting from pressure based on said pressure as a function of time; - comparing the remaining amount of the precursor derived from the capacitance with the remaining amount of the precursor derived from the pressure; - if the capacitance-derived amount of the precursor remaining and the pressure-derived amount of the precursor remaining are equal within a predetermined error limit, quantifying the amount of the precursor remaining comprises setting the amount of the precursor remaining equal to the capacitance-derived amount of the precursor remaining or the pressure-derived amount of the precursor remaining or an interpolated value thereof; - otherwise generating an error signal.

14. 1. A system comprising: a precursor container connector constructed and arranged to operatively connect to a precursor container comprising a precursor; a reaction chamber in fluid communication with said precursor container via precursor lines, the reaction chamber constructed and arranged to receive a plurality of precursor pulses from said precursor container via said precursor lines; a pressure gauge constructed and arranged to sense pressure as a function of time, said pressure as a function of time comprising a plurality of pressure pulses; - a processor, - carrying out an analysis sequence comprising analyzing at least said pressure as a function of time, thereby quantifying the remaining amount of said precursor, - comparing the remaining amount of the precursor with a predetermined amount of the precursor; and - generating a sufficient precursor signal when the remaining amount of the precursor exceeds the predetermined precursor amount; and a processor constructed and arranged to generate an insufficient precursor signal when the remaining amount of the precursor is at most equal to the predetermined precursor amount.

15. The system of claim 14 , wherein the precursor is in a solid state.

16. The system of claim 14 or 15, wherein the precursor comprises a metal center and one or more ligands.

17. 16. The system of claim 14 or 15, wherein the precursor pulse from the multiple precursor pulses includes at least one of a leading edge portion, a hold portion, and a decay portion, and the remaining amount of the precursor is determined by analyzing one or more of the leading edge portion, the hold portion, and the decay portion.

18. 20. The system of claim 17, wherein the raised portion comprises a straight segment and the remaining amount of the precursor is quantified as very low.

19. The system of claim 18 , wherein the pressure gauge is located within the precursor vessel.

20. The system of claim 17 , wherein the leading edge includes a saturated segment and the remaining amount of the precursor is quantified as sufficient.

21. 16. The system of claim 14 or 15, wherein when the sufficient precursor signal is generated, a cyclic deposition process is performed using the precursor in a reaction chamber in fluid communication with the precursor container via the precursor line.

22. 16. The system of claim 14 or 15, wherein when the insufficient precursor signal is generated, the insufficient precursor signal prevents the system from performing a cyclic deposition process using the precursor in a reaction chamber that is in fluid connection with the precursor container via the precursor line.

23. 20. The system of claim 17, wherein the remaining amount of the precursor is determined by analyzing the leading edge, and analyzing the leading edge comprises fitting the leading edge using a function selected from an exponential function, a four parameter logistic function, and an Arrhenius function.

24. 24. The system of claim 23, wherein the exponential function is a three-parameter exponential function of the form P(t)=A-Bexp(-Ct), where A, B, and C are positive real numbers.

25. 16. The system of claim 14 or 15, wherein the precursor container further comprises a capacitance sensor constructed and arranged to measure a sensed capacitance, and the analysis sequence includes determining the remaining amount of the precursor based on the sensed capacitance in addition to the pressure as a function of time.

26. The analysis sequence comprises: - determining a remaining amount of the precursor from the capacitance based on the sensed capacitance; - determining a remaining amount of said precursor resulting from pressure based on said pressure as a function of time; - comparing the remaining amount of the precursor derived from the capacitance with the remaining amount of the precursor derived from the pressure; - if the capacitance-derived amount of the precursor remaining and the pressure-derived amount of the precursor remaining are equal within a predetermined error limit, quantifying the amount of the precursor remaining comprises setting the amount of the precursor remaining equal to the capacitance-derived amount of the precursor remaining or the pressure-derived amount of the precursor remaining or an interpolated value thereof; - otherwise generating an error signal.

27. A precursor container comprising a precursor, a pressure gauge, and a capacitance sensor, - the precursor container is fluidly connectable to a reaction chamber via a precursor line, the reaction chamber and the precursor line being comprised in a deposition system, the reaction chamber being constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line; - said pressure gauge is constructed and arranged to sense pressure as a function of time, said pressure as a function of time comprising a plurality of pressure pulses; - said capacitance sensor is constructed and arranged to measure a sensed capacitance; the precursor container is operatively connectable to a processor contained within the deposition system, the processor comprising: - performing an analysis sequence that includes analyzing one or both of said pressure and said sensed capacitance as a function of time, thereby quantifying the remaining amount of said precursor; - comparing the remaining amount of the precursor with a predetermined amount of the precursor; and - generating a sufficient precursor signal when the remaining amount of the precursor exceeds the predetermined precursor amount; and a precursor container constructed and arranged to generate an insufficient precursor signal when said remaining amount of said precursor is at most equal to said predetermined precursor amount.

28. 28. A precursor container according to claim 27, wherein the precursor is a solid precursor.

29. 29. A precursor container according to claim 27 or 28, wherein the precursor comprises a center and one or more ligands, the center being selected from transition metals, post-transition metals, lanthanides, and metalloids, and the one or more ligands being independently selected from the list consisting of arenes, halides, alkyls, cyclopentadienyls, amides, chelating nitrogen-containing ligands, alkoxides, beta-diketonates, and carbonyls.

30. A data processing unit, a receiving unit constructed and arranged to receive the pressure as a function of time, said pressure as a function of time comprising a plurality of pressure pulses; an analysis unit constructed and arranged to carry out a sequence of analyses of at least said pressure as a function of time, thereby quantifying the remaining amount of precursor; a comparison unit constructed and arranged to compare said remaining amount of said precursor with a predetermined amount of precursor; a generation unit, said generation unit comprising: - generating a sufficient precursor signal when the remaining amount of the precursor exceeds the predetermined precursor amount; and a generating unit constructed and arranged to generate an insufficient precursor signal when said remaining amount of said precursor is at most equal to said predetermined precursor amount.

31. A computer program product comprising instructions for causing a data processing unit according to claim 30 to carry out the method according to claim 1 or 2.

32. 32. A computer readable medium having stored thereon the computer program product of claim 31.

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