Method and system for precursor level monitoring

Abstract

Methods and related systems, precursor containers, data processing systems, computer program products, and computer readable media useful for determining an amount of precursor in a precursor container. Embodiments of the presently described methods may include performing, by a processor, an analysis sequence of pressure at least as a function of time to quantify a precursor remainder.

Description

Technical Field

[0001] The present disclosure belongs to the field of integrated device manufacturing, particularly to the field of vapor deposition tools, systems and processes for integrated circuit manufacturing, and more particularly to techniques for determining the amount of precursors (eg, solid precursors) in precursor containers for semiconductor manufacturing processes. Background Art

[0002] As semiconductors and semiconductor manufacturing processes become more advanced, there is a need for better uniformity and process control during manufacturing.

[0003] In processes such as atomic layer deposition (ALD), epitaxy, and chemical vapor deposition (CVD), precursors, which may be in gaseous, liquid, or solid form, are deposited onto or in contact with a workpiece. These precursors are typically stored in precursor containers or precursor vessels, from which they are delivered to the workpiece in a reaction chamber.

[0004] When executing the process, it may be advantageous to monitor the amount of precursor in the precursor container to prevent manufacturing defects due to depletion of precursor material. The ability to monitor the remaining amount of precursor material in the precursor container is important because it ensures process quality, allows for efficient scheduling of precursor container changes, maximizes the use of expensive chemicals, and improves 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 complex. Typically, the precursor material is transported from a precursor container to a reaction chamber by flowing a carrier gas through the precursor container, thereby generating a process gas comprising a carrier gas and evaporated solid precursor, which is then provided to the process chamber. Several process conditions employed during manufacturing (e.g., high temperature ranges, use of carrier gas, etc.) cause monitoring of precursor levels to become challenging for existing level sensing systems, especially when resolution and accuracy are critical.

[0006] Therefore, there is a need for improved methods and apparatus for monitoring the amount of solid precursor in a precursor container for a semiconductor manufacturing process. Summary of the invention

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

[0008] A system is also described herein, which includes a precursor container connector, which is constructed and arranged to be operably connected to a precursor container including a precursor (e.g., a solid precursor). The reaction chamber can be connected to the precursor container fluid via a precursor line. The reaction chamber can be constructed and arranged to receive multiple precursor pulses from the precursor container via a precursor line. The system can also include a pressure gauge, which is constructed and arranged to sense pressure as a function of time. The pressure as a function of time can include multiple pressure pulses. The system can also include a processor. The processor can be constructed and arranged to perform an analysis sequence, which includes analyzing at least the pressure as a function of time, thereby quantifying the precursor remaining amount; comparing the precursor remaining amount with a predetermined precursor amount; and comparing the precursor remaining amount with a predetermined precursor amount. If the precursor remaining amount exceeds the predetermined precursor amount, the processor can generate a sufficient precursor signal. If the precursor remaining amount 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 includes 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 rise portion, a sustain portion, and a decay portion. The amount of precursor remaining can be determined by analyzing one or more of the rise portion, the sustain portion, and the decay portion.

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

[0013] In some embodiments, a pressure gauge is located in the precursor container.

[0014] In some embodiments, the rising portion includes a saturation segment, and the precursor remaining amount is quantified as sufficient. In some embodiments, the saturation segment of the rising portion can be considered as a continuous portion, or modeled as a continuous portion.

[0015] In some embodiments, if a sufficient precursor signal is generated, a cyclic deposition process may be performed using the precursor in a reaction chamber that is fluidly connected to the precursor container via a precursor line.

[0016] In some embodiments, if an 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 fluidly connected to the precursor container via a precursor line.

[0017] In some embodiments, the amount of precursor remaining is determined by analyzing the rise portion. Analyzing the rise portion may include fitting the rise 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) = A-Bexp(-Ct). A, B, and C may be positive real numbers.

[0019] In some embodiments, the precursor container further comprises a capacitive sensor constructed and arranged to measure a sensed capacitance.The analysis sequence may comprise determining the amount of precursor remaining based on the sensed capacitance and the pressure as a function of time.

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

[0021] A precursor container is also described herein, comprising a precursor, a pressure gauge and a capacitive sensor. The precursor container can be connected to a reaction chamber via a precursor line fluid. The reaction chamber and the precursor line can be included in a vapor deposition system. The reaction chamber can be constructed and arranged to receive multiple precursor pulses from the precursor container via the precursor line. The pressure gauge can be constructed and arranged to sense the pressure as a function of time, and the pressure as a function of time includes multiple pressure pulses. The capacitive sensor can be constructed and arranged to measure the sensing capacitance. The precursor container can be operably connected to a processor included in the vapor deposition system, which is constructed and arranged to perform an analysis sequence, which includes analyzing one or both of the pressure as a function of time and the sensing capacitance, thereby quantifying the remaining amount of the precursor; comparing the remaining amount of the precursor with a predetermined amount of the precursor; and, if the remaining amount of the precursor exceeds the predetermined amount of the precursor, a sufficient precursor signal is generated; and if the remaining amount of the precursor is at most equal to the predetermined amount of the precursor, an insufficient precursor signal is generated.

[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 a transition metal, a post-transition metal, a lanthanide, and a metalloid; and wherein the one or more ligands are independently selected from an arene, a halide, an alkyl, a cyclopentadienyl, an amide, a chelating nitrogen-containing ligand, an alkoxide, a β-diketonate, and a carbonyl.

[0024] The present invention also describes a data processing unit, comprising: a receiving unit, which is constructed and arranged to receive pressure as a function of time, the pressure as a function of time including multiple pressure pulses; an analyzing unit, which is constructed and arranged to perform an analysis sequence of at least pressure as a function of time, thereby quantifying the remaining amount of precursor; a comparing unit, which is constructed and arranged to compare the remaining amount of precursor with a predetermined amount of precursor; and a generating unit, which is constructed and arranged to generate a sufficient precursor signal if the remaining amount of precursor exceeds the predetermined amount of precursor; and the generating unit is also constructed and arranged to generate an insufficient precursor signal if the remaining amount of precursor is at most equal to the predetermined amount of precursor.

[0025] Further described herein is a computer program product comprising instructions for causing a data processing unit described herein to perform the steps of the method described herein.

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

[0027] This summary is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the detailed description of the example embodiments disclosed below. This summary is not intended to identify the 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 An embodiment of a processing system 100 is shown.

[0029] Figure 2A and 2B An embodiment of a subsystem 200 is shown.

[0030] Figure 3 An example of pressure variation over time for a full container is shown.

[0031] Figure 4A , 4B 4C shows a stylized pressure versus time curve 400 for a precursor pulse embodiment.

[0032] It should be understood that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be exaggerated relative to other elements to help improve the understanding of the illustrated embodiments of the present disclosure. DETAILED DESCRIPTION

[0033] Although certain embodiments and examples are disclosed below, those skilled in the art will appreciate that the invention extends beyond the specifically disclosed embodiments and / or uses of the invention and their obvious modifications and equivalents. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specifically disclosed embodiments described below.

[0034] As used herein, the term "substrate" may refer to any one or more underlying materials, including any one or more underlying materials that may be modified or 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. A substrate may be in any form, such as a powder, a plate, or a workpiece. A plate-like substrate may include wafers of various shapes and sizes. A substrate may be made of semiconductor materials, including, for example, silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide.

[0035] For example, a substrate in powder form can be used in drug manufacturing. The porous substrate can include a polymer. Examples of workpieces can include medical devices (such as stents and syringes), jewelry, tool equipment, components for battery manufacturing (such as anodes, cathodes, or separators), or components of photovoltaic cells, etc.

[0036] The continuous substrate may extend beyond the boundaries of the processing chamber in which the deposition process occurs. In some processes, the continuous substrate may be moved through the processing chamber so that the process continues until the end of the substrate is reached. The continuous substrate may be provided from a continuous substrate feed system to allow the continuous substrate to be manufactured and output in any suitable form.

[0037] Non-limiting examples of continuous substrates may include sheets, nonwoven films, rolls, foils, webs, flexible materials, bundles of continuous filaments or fibers (eg, ceramic fibers or polymer fibers). A continuous substrate may also include a carrier or sheet on which a discontinuous substrate is mounted.

[0038] As used herein, the term "deposition process" may refer to the introduction of precursors (and / or reactants) into a reaction chamber to deposit a layer on a substrate. A "cyclic deposition process" is an example of a "deposition process".

[0039] The term "cyclic deposition process" or "cyclic deposition process" may 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 including an ALD component and a cyclic CVD component.

[0040] The term "atomic layer deposition" may refer to a vapor deposition process in which a deposition cycle (usually multiple continuous deposition cycles) is performed in a processing chamber. The term atomic layer deposition used herein also means a process including processes specified by related terms, such as chemical vapor atomic layer deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas source MBE, organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of precursor / reactant gas and purge gas (e.g., inert carrier gas). Pulses may include exposing a substrate to a precursor or reactant. This may be achieved, for example, by introducing a precursor or reactant into a reaction chamber where a substrate is present. Additionally or alternatively, exposing a substrate to a precursor may include moving the substrate to a position in a substrate processing system where a reactant or precursor is present.

[0041] Typically, for an ALD process, during each cycle, a precursor is introduced into a reaction chamber and is chemically adsorbed onto a deposition surface (e.g., a substrate surface that may include previously deposited material or other material from a previous ALD cycle) and forms a monolayer or sub-monolayer of material that does not readily react with additional precursors (i.e., a self-limiting reaction). Thereafter, a reactant (e.g., another precursor or a reactive gas) may subsequently be introduced into the process chamber for converting the chemically adsorbed precursor to the desired material on the deposition surface. The reactant is capable of further reacting with the precursor. In one or more cycles, such as in each step of each cycle, a purge step may be utilized to remove any excess precursor from the process chamber and / or to remove any excess reactant and / or reaction byproducts from the reaction chamber.

[0042] As used herein, the term "purging" may refer to the process of providing an inert or substantially inert gas to a reaction chamber between two gas pulses that react with each other. For example, a purge, such as with an inert gas, may be provided between a precursor pulse and a reactant pulse to avoid or at least minimize gas phase interactions between the precursor and the reactant. In some embodiments, "purging" may refer to the process of providing a reactive purge gas to a reaction chamber between two gas pulses that react with each other and with the purge gas.

[0043] It should be understood that purging and pulsing can be achieved in time or space, or both. For example, in the case of time purging, the purging step can be used, for example, in a time sequence of providing a first precursor to a reaction chamber, providing a purge gas to the reaction chamber, and providing a second precursor to the reaction chamber, wherein the substrate on which the layer is deposited does not move. For example, in the case of space purging, the purging step can take the following form: the substrate is moved from a first position where the first precursor is continuously supplied to a second position where the second precursor is continuously supplied through a purge gas curtain. For example, in the case of time pulsing, the precursor can be provided within a predetermined time before and after the inert gas is provided to the reaction chamber. For example, in the case of space pulsing, the substrate can be moved through a predetermined position, the precursor is provided at the predetermined position, and the predetermined position is surrounded by one or more inert purge gas curtains.

[0044] As used herein, "precursor" includes gases or materials that can be changed into a gaseous state and can be represented by a chemical formula that includes elements that can be introduced into the deposition process described herein.

[0045] The illustrations presented herein are not meant to be actual views of any particular material, structure, or device but are merely idealized representations used to describe embodiments of the present disclosure.

[0046] The specific embodiments shown and described are illustrations of the present invention and its best mode and are not intended to limit the scope of these aspects and embodiments in any way. In fact, for the sake of brevity, the traditional manufacturing, connection, preparation and other functional aspects of the system may not be described in detail. In addition, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and / or physical connections between various elements. Many alternative or additional functional relationships or physical connections may exist in actual systems, and / or may not exist in some embodiments.

[0047] It should be understood that the configuration and / or method described herein are exemplary in nature, and these specific embodiments or examples should not be considered restrictive, because many variations are possible. The specific routine or method described herein can represent one or more of any number of processing strategies. Therefore, the various actions shown can be performed in the order shown, in other orders, or omitted in some cases.

[0048] Methods, systems, computer program products, precursor containers, and computer-readable media are described herein that allow the determination of the amount of precursor contained in a precursor container when in use. Such information is very useful for preventing errors associated with precursor depletion.

[0049] In some embodiments of the methods described herein, a plurality of precursor pulses are provided from a precursor container to a precursor line fluidically connected to the precursor container. The precursor container may be completely full, or may be partially empty. In other words, the precursor container includes a precursor. For example, the precursor container may be filled with 100%, 90%, 80%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or 5% of the precursor. It should be understood that these percentages may be appropriately expressed as mass percentages, i.e., "the mass of the amount of precursor remaining in the precursor container" divided by "the mass of the precursor in the precursor container when the precursor container is full".

[0050] During normal operation of a pulsed deposition process, such as an atomic layer deposition process, the valves may be operated sequentially to provide precursors from a precursor container to a reaction chamber in multiple pulses. For example, the following sequence comprising two alternating steps a) and b) may 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 sublimates, the precursor in the container gradually rises to the vapor pressure of the precursor; b) the container valve is opened, precursor is provided from the precursor container, and the pressure in the precursor container decreases. The inventors surprisingly found 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.

[0051] Thus, embodiments of the presently described methods may include sensing pressure as a function of time by a pressure gauge, the pressure comprising a plurality of pressure pulses. In some embodiments, these pressure increases may be measured by a pressure gauge located in the precursor container. In some embodiments, the pressure decrease may be measured by a pressure gauge located in the precursor container, or by a pressure gauge located in a precursor line downstream of the precursor container and upstream of the reaction chamber.

[0052] Embodiments of the presently described methods may include performing, by a processor, a sequence of analyses of at least the pressure as a function of time. Thus, the amount of precursor remaining may be quantified.

[0053] Embodiments of the presently described methods may include comparing a precursor remaining amount to a predetermined precursor amount. If the precursor remaining amount exceeds the predetermined precursor amount, a sufficient precursor signal may be generated. On the other hand, if the precursor remaining amount is at most equal to the predetermined precursor amount, an insufficient precursor signal may be generated. In some embodiments, the sufficient precursor signal may result in a vapor deposition process using the precursor being performed. In some embodiments, the insufficient precursor signal may result in a vapor deposition process using the precursor being prevented from being performed.

[0054] In some embodiments, methods disclosed herein may 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 precursor consumption rate may 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 precursor consumption rate is equal to a precursor increment divided by a time increment, wherein the precursor increment is equal to the second predetermined amount of precursor minus the first predetermined amount of precursor, and wherein the time increment is equal to the second time minus the first time.

[0055] In some embodiments, the methods described herein can include generating an excess precursor depletion signal when a precursor consumption rate exceeds a predetermined precursor amount. When the excess precursor depletion signal is generated, a deposition process using the precursor can be automatically terminated, such as by stopping the precursor flow.

[0056] In some embodiments, pressure measurement can be used to derive dosage during pulses, such as during a single pulse. Dose can refer to the total amount of precursor extracted from the precursor container during a single pulse. In some embodiments, the dosage can be measured using a pressure gauge located inside the precursor container. In some embodiments, between two subsequent pulses (previous pulse and next pulse), the precursor container is closed, i.e., its inlet and outlet valves are closed. In such embodiments, the dosage can be determined by the pressure measurement immediately after the previous pulse and the pressure measurement immediately before the next pulse. The additional molecular weight in the gas phase before the next pulse is equal to the dosage compared to after the previous pulse. This amount can be easily derived using gas laws, such as the ideal gas law or the real gas law (van der Waals law).

[0057] In some embodiments, the precursor containers described herein include a precursor in solid form, ie, a solid precursor.

[0058] The dose is seen just before the container inlet and / or outlet valves are opened. It results from the increase that occurs during the time when the valves are closed and the container is isolated.

[0059] Further described herein is a system. In some embodiments, the system can be constructed and arranged to perform a cyclic vapor deposition method, such as atomic layer deposition. In some embodiments, the system is constructed and arranged to perform the methods described herein.

[0060] A system as described herein can include a precursor container connector constructed and arranged to be operably connected to a precursor container. The precursor container includes a precursor. In some embodiments, the precursor container is included in the system.

[0061] The system may further include a reaction chamber fluidly connected to the precursor container via a 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.

[0062] The system may further include a pressure gauge constructed and arranged to sense pressure as a function of time.The pressure as a function of time may include a plurality of pressure pulses.

[0063] The system may also include a processor. The processor may be constructed and arranged to perform an analysis sequence that includes analyzing at least the pressure as a function of time to quantify the amount of precursor remaining. The analysis sequence may also include comparing the amount of precursor remaining to a predetermined amount of precursor. The analysis sequence may also include comparing the amount of precursor remaining to a predetermined amount of precursor. If the amount of precursor remaining exceeds the predetermined amount of precursor, the processor may generate a sufficient precursor signal. If the amount of precursor remaining is at most equal to the predetermined amount of precursor, the processor may generate an insufficient precursor signal.

[0064] Figure 1 An embodiment of a processing system 100 is shown including one or more processing 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 .

[0065] The processing chamber 102 may include any suitable processing chamber, such as an atomic layer deposition (ALD) or chemical vapor deposition (CVD) reactor chamber.

[0066] The precursor gas source 104 may include a precursor container and one or more precursors described herein, either alone or mixed with one or more carrier gases (eg, inert gases). Suitably, at least one precursor container includes a capacitive sensor system as described herein.

[0067] Reactant gas source 106 may include a container and one or more reactants as described herein - alone or mixed with one or more carrier gases. Purge gas source 108 may include one or more noble gases, such as He, Ne, Ar, Kr and / or Xe. Although four gas sources 104-108 are shown, system 100 may include any suitable number of gas sources. Gas sources 104-108 may be coupled to process chamber 102 via pipelines 114-118, and pipelines 114-118 may each include a flow controller, a valve, a heater, etc. At least one gas source includes at least one of the pressure-based and capacitance-based precursor level sensing mechanisms disclosed herein.

[0068] The exhaust device 110 may include one or more vacuum pumps.

[0069] The process control unit 112 includes electronic circuits and software to selectively operate valves, manifolds, heaters, pumps and other components included in the system 100. Such circuits and components are used to introduce precursors and purge gases from the corresponding sources 104-108. The process control unit 112 can control the timing of gas pulse sequences, the temperature of the substrate and / or the processing chamber, the pressure in the processing chamber, and various other operations to provide the correct operation of the system 100. The process control unit 112 may include control software to control the flow of precursors, reactants and purge gases into and out of the processing chamber 102 by electrically or pneumatically controlling valves. The process control unit 112 may include modules that perform certain tasks, such as software or hardware components, such as FPGAs or ASICs. The modules can be advantageously configured to reside on an addressable storage medium of the control system and configured to perform one or more processes.

[0070] Other configurations of the system 100 are possible, including different numbers and types of precursor and reactant sources and purge gas sources. In addition, it should be understood that there are many arrangements of valves, conduits, precursor sources, and purge gas sources that can be used to achieve the goal of selectively supplying gases into the process chamber 202. In addition, as a schematic representation of the system, many components have been omitted for simplicity of illustration, and these components may include, for example, various valves, manifolds, purifiers, heaters, containers, vents, and / or bypasses.

[0071] During operation of the reactor system 100, a substrate, such as a semiconductor wafer (not shown), is transferred from, for example, a substrate handling system to the processing chamber 102. Once the substrate is transferred to the processing chamber 102, one or more gases, such as precursors, reactants, carrier gases, and / or purge gases, are introduced into the processing chamber 102 from gas sources 104-108.

[0072] A precursor container is also described herein, which includes a precursor, a pressure gauge and a capacitive sensor. The precursor container can be connected or connectable to a reaction chamber via a precursor pipeline fluid. The reaction chamber and the precursor pipeline can be included in a vapor deposition system. The reaction chamber can be constructed and arranged to receive multiple precursor pulses from the precursor container via the precursor pipeline. The pressure gauge can be constructed and arranged to sense the pressure as a function of time. The pressure as a function of time can include multiple pressure pulses. The capacitive sensor is constructed and arranged to measure the sensing capacitance. The sensing capacitance can indicate the remaining amount of the precursor. In addition, the precursor container can be operably connected to a processor included in the vapor deposition system. The processor can be constructed and arranged to perform an analysis sequence, which includes analyzing one or both of the pressure and the sensing capacitance as a function of time. Therefore, the remaining amount of the precursor can be quantified. The processor can also be constructed and arranged to compare the remaining amount of the precursor with a predetermined amount of the precursor. The processor can also be constructed and arranged to generate a sufficient precursor signal if the remaining amount of the precursor exceeds the predetermined amount of the precursor. The processor may also be constructed and arranged to generate an insufficient precursor signal if the remaining amount of precursor is at most equal to a predetermined amount of precursor.

[0073] A data processing unit is also described herein. In some embodiments, the data processing unit may include a processor. The data processing unit may include a receiving unit, which is constructed and arranged to receive pressure as a function of time. The pressure as a function of time includes multiple pressure pulses. The data processing unit may also include an analysis unit. The analysis unit may be constructed and arranged to perform an analysis sequence of at least pressure as a function of time. Therefore, the remaining amount of precursor can be quantified. The analysis unit also includes a comparison unit, which is constructed and arranged to compare the remaining amount of precursor with a predetermined amount of precursor. The analysis unit also includes a generation unit. If the remaining amount of precursor exceeds the predetermined amount of precursor, the generation unit may be constructed and arranged to generate a sufficient precursor signal. The generation unit may also be constructed and arranged to generate an insufficient precursor signal if the remaining amount of precursor is at most equal to the predetermined amount of precursor.

[0074] Further described herein is a computer program product comprising instructions to cause a data processing unit described herein to perform the steps of a method according to an embodiment of the present disclosure.

[0075] Also described herein is a computer-readable medium having stored thereon a computer program product according to the present disclosure.

[0076] In some embodiments according to the present disclosure, the precursor may be solid. In other words, in some embodiments, the precursor consists essentially of a solid precursor, or may include a solid precursor.

[0077] In some embodiments, the precursor includes a precursor center and one or more ligands. The precursor center can, for example, include 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.

[0078] In some embodiments, one or more ligands are independently selected from aromatic hydrocarbons, halides, alkyls, cyclopentadienyls, amides, chelated nitrogen-containing ligands, alkoxides, β-diketonates, and carbonyls. For example, suitable metal diaromatic hydrocarbons include M(Bz)2 and M(RBz)2, wherein 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, wherein Cp is a cyclopentadienyl. Suitable transition metals include tungsten, molybdenum, and ruthenium. Suitable transition metal halides include MoCl5 and HfCl4. For example, suitable transition metal β-diketonates include W(thd)3, wherein thd represents 2,2,6,6-tetramethyl-3,5-heptanedione.

[0079] Suitable precursors are described, for example, in “Barry, Seán 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.”, which is incorporated herein by reference in its entirety.

[0080] Further references Figure 2A and 2B , which shows an embodiment of a subsystem 200, which includes a precursor container 210, a precursor line 220, and pressure gauges 215, 225. Figure 2A In the embodiment of FIG. 2 , the pressure gauge 215 is installed in the precursor container 210. Figure 2B In the embodiment of FIG. 2 , a pressure gauge 225 is installed in the precursor line 220 .

[0081] Reference now Figure 2AIn some embodiments of the present disclosure, a pressure gauge 215 is included in the precursor container 210. When the precursor container 210 is isolated from the rest of the system in which the pressure container 210 is embedded, the pressure gauge 215 can monitor the container pressure increase characteristics. In particular, during a single ALD cycle, the precursor container can only be opened for a short time - during most of the cycle, all container valves (not shown) can be closed. When the container valves are closed, precursor vapor is generated in the container and the pressure in the container gradually increases. In embodiments of the present disclosure, the rate and overall shape of this pressure increase can be used to characterize the amount of precursor remaining.

[0082] In particular, steam generation and subsequent pressure increase (rate and nonlinearity) can depend on the amount of precursor available in the container. When the container is empty, the pressure will not increase due to the generation of the precursor vapor. Under near-empty conditions, the pressure increase may appear to be linear. When the container is full, the pressure increase curve can be a saturation curve, with an initial linear region, followed by a slow, gradually slowing increase caused by the vapor pressure reaching saturation. This behavior can be modeled with (for example) a three-parameter exponential function, which is a linearly increasing curve whose curved portion is limited by asymptotes. The curve shape can be represented by a slope with the correct coefficient, which means that the steam generation phenomenon can be correctly modeled using the selected slope function (within a reasonable time limit), which can cause the actual precursor amount to be related to the slope coefficient. Additionally or alternatively, other slope functions can be used to fit the pressure curve, such as four-parameter logic and Arrhenius type formulas.

[0083] Figure 3 An example of pressure variation over time for a full container is shown, where time is given in seconds and pressure is given in Torr. Pressure as a function of time is fit using a triple exponential function of the form P(t) = A-Bexp(-Ct), where A is 5.94, B is 6.3, and C is 0.24.

[0084] In some embodiments of the present disclosure, the pressure gauge is included 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. Installing the pressure gauge in the precursor container can result in more accurate measurements compared to installing the precursor container in the precursor line.

[0085] refer to Figure 4A , which shows a stylized pressure versus time curve 400 of an embodiment of a precursor pulse, a pulse from a plurality of pulses includes at least one of a rising portion 410, a sustaining portion 420, and a decaying portion 430. Thus, the amount of precursor remaining can be determined by analyzing one or more of the rising portion 410, the sustaining portion 420, and the decaying portion 430. In some embodiments, and with reference to Figure 4B, which shows another embodiment of a stylized pressure versus time curve 400 , a pulse from a plurality of pulses may include a rising portion 410 and a decaying portion 430 .

[0086] In some embodiments, the amount of precursor remaining is quantified based on the rise portion 410 .

[0087] In some embodiments, the rising portion 410 includes a linear segment, and the amount of precursor remaining is quantified as very low. For example, "very low" may mean that the precursor container is empty or almost empty, for example, "almost empty" may 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.

[0088] Statistical methods can be used to determine when the rising portion 410 includes a linear segment, or when it includes a saturated segment. For example, saturation or curvature can be tested by starting with the assumption that "the rising portion is linear", which should be an incorrect assumption in the case where the rising portion includes a saturated segment, and performing a linear fit on the rising portion. If the R squared of the linear fit is above 0.95 (95%), then we cannot prove ourselves wrong and we need to accept the conclusion that the rising portion includes a linear segment. If the R squared is less than 0.95, we cannot say with certainty that the line is straight, and the other conclusion, that the rising portion includes a saturated segment, is true.

[0089] In some embodiments, the rising portion 410 includes a saturation section. In this case, the amount of precursor remaining can be quantified as sufficient. Figure 4B and 4C A rising portion 410 including a saturation segment is shown in FIG.

[0090] In some embodiments, Figure 4A and 4B As shown, the measured pressure may increase during the rising portion 410. This may occur, for example, when the pressure gauge is installed in a precursor line.

[0091] In some embodiments, Figure 4C As shown, during the rising part, the measured pressure will decrease. This can happen, for example, when the pressure gauge is installed in the precursor container.

[0092] In some embodiments, the amount of precursor remaining is determined by analyzing the rising portion. Analyzing the rising portion may include fitting the rising portion using a function. The function may be, for example, selected from an exponential function, a four-parameter logistic function, and an Arrhenius function.

[0093] In some embodiments, the logic function is a four-parameter function of the form F(x)=D+(AD) / (1+(x / C)^B, where A, B, C, and D are real numbers, such as positive or negative real numbers.

[0094] 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, such as positive or negative real numbers. Figure 2B As shown, this occurs when a pressure gauge 225 is installed in the precursor line 220.

[0095] 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, such as positive or negative real numbers. Figure 2A This occurs when a pressure gauge 215 is installed in the precursor container 210 as shown.

[0096] In some embodiments, particularly when sufficient precursor signals are generated, a cyclic deposition process can be performed using the precursor in a reaction chamber that is fluidly connected to the precursor container via a precursor line. Thus, a cyclic deposition process can be performed.

[0097] In some embodiments, if an 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 fluidly connected to the precursor container via a precursor line.

[0098] Providing a pressure-based precursor level measurement according to the present disclosure allows for measuring the amount of precursor remaining, thereby allowing the question of "when do we need to refill the container" to be answered. However, no measurement method is necessarily foolproof, and the precursor level measurement may be wrong. In fact, if one can measure the amount of material in the precursor container, this does not guarantee that the chemical is complete or will operate as expected. Therefore, it may be useful to add redundancy to the precursor level measurement and install additional precursor level sensors. For example, in addition to a pressure-based precursor level sensor, a capacitive precursor level sensor can also be used. In fact, both types of sensors can be used in the system to provide a comprehensive picture of what is happening inside the precursor container. The advantage here is that we have two independent observations, observing similar things, but based on different phenomena. When the sensor data is consistent, this indicates that the operating state of the container is stable. However, when the data is inconsistent, it provides valuable information about stability, potential sources of instability, and improves the prediction of source failure. In some embodiments, the precursor level determination based on capacitance and pressure data is more accurate than the precursor level determination based on only one type of data.

[0099] Thus, in some embodiments, the precursor container further comprises a capacitive sensor constructed and arranged to measure a sensed capacitance. In such embodiments, the analysis sequence may comprise determining the amount of precursor remaining based on the sensed capacitance and the pressure as a function of time.

[0100] Suitable capacitive sensors are described in US Provisional Application No. 63 / 369,695, which is incorporated herein by reference in its entirety.

[0101] In some embodiments, the analysis sequence may include determining a capacitance-derived precursor remaining amount based on the sensed capacitance. Additionally, a pressure-derived precursor remaining amount may be determined based on the pressure as a function of time. The capacitance-derived precursor remaining amount and the pressure-derived precursor remaining amount may then be compared. Equality of these parameters within a predetermined error range may indicate correct operation. Conversely, inequality of these parameters within a predetermined error range may indicate an error during precursor level measurement. In some embodiments, the system may be prevented from processing a substrate when the capacitance-derived precursor remaining amount and the pressure-derived precursor remaining amount are unequal within a predetermined error range.

[0102] Thus, if the capacitance-derived precursor remaining amount and the pressure-derived precursor remaining amount are equal within a predetermined error range, such as 10%, 5%, 2%, 1% or 0.1%, this may indicate a correctly measured precursor remaining amount, and quantizing the precursor remaining amount includes setting the precursor remaining amount equal to the capacitance-derived precursor remaining amount, the pressure-derived precursor remaining amount, or an interpolated value thereof. For example, the interpolation may refer to an average, weighted average or mean of the pressure-derived precursor remaining amount and the capacitance-derived precursor remaining amount. Otherwise, i.e., if the capacitance-derived precursor remaining amount and the pressure-derived precursor remaining amount are not equal within a predetermined error range, an error signal may be generated.

[0103] In some embodiments, pressure measurements and capacitance measurements are used to obtain precursor stability. In practice, when the capacitance precursor level measurement indicates a much higher fill level than the pressure measurement, for example when the capacitance-derived precursor level is 10%, 20%, 30%, or 40% higher than the pressure-derived precursor level, the precursor can be determined to be unstable. For example, when the capacitance measurement shows a 50% fill level, while the pressure measurement shows a 10% fill level, it can be inferred that the precursor has at least partially decomposed, i.e., it can be inferred that the precursor is unstable.

[0104] In some embodiments, pressure measurements and capacitance measurements are used to derive fill levels and predicted depletion. In fact, these two different sensing mechanisms can be used in tandem to obtain robust estimates of fill levels and depletion rates (including loss of precursors through decomposition and similar means). If we have an estimate of the precursor "loss rate", we can infer and schedule refills (and backup tools in production) with a reasonably high confidence level.

[0105] The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts and / or properties disclosed herein, and any and all equivalents thereof.

Claims

1. A method comprising: - providing a plurality of precursor pulses from a precursor container to a precursor line fluidically connected to the precursor container; The precursor container includes a precursor; - sensing the pressure as a function of time by means of a pressure gauge, the pressure comprising a plurality of pressure pulses; - performing, by a processor, a sequence of analyses of at least the pressure as a function of time, thereby quantifying the amount of precursor remaining; as well as - comparing the remaining amount of precursor to a predetermined amount of precursor; and - if the remaining amount of precursor exceeds a predetermined amount of precursor, generating a sufficient precursor signal; or - If the remaining amount of precursor is at most equal to a predetermined amount of precursor, an insufficient precursor signal is generated.

2. A system comprising: - a precursor container connector constructed and arranged for operative connection to a precursor container comprising a precursor; - a reaction chamber fluidly connected to the precursor container via a precursor line; the reaction chamber being constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line; - a pressure gauge constructed and arranged to sense pressure as a function of time, the pressure as a function of time comprising a plurality of pressure pulses; as well as - a processor constructed and arranged to: - performing an analysis sequence comprising analyzing at least the pressure as a function of time to quantify the amount of precursor remaining; - comparing the remaining amount of precursor to a predetermined amount of precursor; and - comparing the remaining amount of precursor to a predetermined amount of precursor; and - if the remaining amount of precursor exceeds a predetermined amount of precursor, generating a sufficient precursor signal; and - If the remaining amount of precursor is at most equal to a predetermined amount of precursor, an insufficient precursor signal is generated.

3. The method or system according to claim 1 or 2, wherein: The precursor is in a solid state.

4. The method or system according to any one of claims 1 to 3, wherein: The precursor includes a metal center and one or more ligands.

5. The method or system according to any one of claims 1 to 4, wherein: A precursor pulse from the plurality of precursor pulses includes at least one of a rise portion, a sustain portion, and a decay portion, and wherein the precursor remainder is determined by analyzing one or more of the rise portion, the sustain portion, and the decay portion.

6. The method or system according to claim 5, wherein: The rising portion includes a linear segment, and wherein the precursor remaining amount is quantified to be extremely low.

7. The method or system according to claim 6, wherein: The pressure gauge is located in the precursor container.

8. The method or system according to claim 5, wherein: The rising portion includes a saturation section, and wherein the remaining amount of the precursor is quantified to be sufficient.

9. The method or system according to any one of claims 1 to 8, wherein: If the sufficient precursor signal is generated, a cyclic deposition process is performed using the precursor in a reaction chamber that is fluidly connected to the precursor container via the precursor line.

10. The method or system according to any one of claims 1 to 8, wherein: If 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 fluidly connected to the precursor container via the precursor line.

11. A method or system according to any one of claims 5 to 10, wherein: The remaining amount of the precursor is determined by analyzing the rising portion, and wherein analyzing the rising portion includes fitting the rising portion using a function selected from an exponential function, a four-parameter logistic function, and an Arrhenius function.

12. The method or system of claim 11, 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.

13. The method or system according to any one of claims 1 to 12, wherein: The precursor container further includes a capacitive sensor constructed and arranged to measure a sensed capacitance, and wherein the analysis sequence includes determining the amount of precursor remaining based on the sensed capacitance and pressure as a function of time.

14. The method or system of claim 13, wherein: The analysis sequence includes: - based on said sensed capacitance, determining a capacitive derived amount of precursor remaining; - determining a pressure-derived amount of precursor remaining based on the pressure as a function of time; - comparing the capacitance-derived precursor remaining amount and the pressure-derived precursor remaining amount; and - if the capacitance-derived precursor remaining amount and the pressure-derived precursor remaining amount are equal within a predetermined error range, quantizing the precursor remaining amount includes setting the precursor remaining amount equal to the capacitance-derived precursor remaining amount, the pressure-derived precursor remaining amount, or an interpolated value thereof; - Otherwise, an error signal is generated.

15. A precursor container comprising a precursor, a pressure gauge and a capacitive sensor: - the precursor container is fluidly connectable to a reaction chamber via a precursor line, the reaction chamber and the precursor line being included in a vapor deposition system, the reaction chamber being constructed and arranged to receive a plurality of precursor pulses from the precursor container via the precursor line; - the pressure gauge is constructed and arranged to sense pressure as a function of time, the pressure as a function of time comprising a plurality of pressure pulses; - the capacitive sensor is constructed and arranged to measure a sensing capacitance; The precursor container is operably connected to a processor contained in the vapor deposition system, the processor being constructed and arranged to: - performing an analysis sequence comprising analyzing one or both of pressure and sensed capacitance as a function of time to quantify the amount of precursor remaining; - comparing the remaining amount of precursor to a predetermined amount of precursor; and - if the remaining amount of precursor exceeds a predetermined amount of precursor, generating a sufficient precursor signal; and - If the remaining amount of precursor is at most equal to a predetermined amount of precursor, an insufficient precursor signal is generated.

16. The precursor container according to claim 15, wherein The precursor is a solid precursor.

17. The precursor container according to claim 15 or 16, wherein: 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 wherein the one or more ligands are independently selected from arenes, halides, alkyls, cyclopentadienyls, amides, chelated nitrogen-containing ligands, alkoxides, β-diketonates and carbonyls.

18. A data processing unit, comprising: a receiving unit constructed and arranged to receive the pressure as a function of time, the pressure as a function of time comprising a plurality of pressure pulses, - an analysis unit constructed and arranged to perform a sequence of analyses of at least the pressure as a function of time, thereby quantifying the amount of precursor remaining; - a comparison unit constructed and arranged to compare the remaining amount of the precursor with a predetermined amount of the precursor; as well as - a production unit constructed and arranged to: - if the remaining amount of precursor exceeds a predetermined amount of precursor, generating a sufficient precursor signal; and - If the remaining amount of precursor is at most equal to a predetermined amount of precursor, an insufficient precursor signal is generated.

19. A computer program product comprising instructions for causing a data processing unit according to claim 18 to execute a method according to any one of claims 1 or 3 to 15.

20. A computer readable medium having stored thereon a computer program product according to claim 19.

Images