Method of delivering a liquid precursor into a thin film deposition chamber

Abstract

The disclosed technology generally relates to semiconductor processing, and more specifically to a liquid precursor injection apparatus and method for depositing thin films. One method of injecting a liquid precursor into a thin film deposition chamber includes atomizing the liquid precursor into atomized precursor droplets using a liquid injection unit, vaporizing the atomized precursor droplets into a vaporized liquid precursor in a vaporization chamber, and delivering the vaporized liquid precursor into the thin film deposition chamber. The liquid injection unit and the liquid precursor cause the operation of the liquid precursor delivery unit under relatively low stability conditions—a first liquid precursor temperature at the liquid injection unit, a first liquid precursor pressure upstream of the liquid precursor injection unit, and a first gas pressure downstream of the liquid precursor injection unit—to cause a change in the mass flow rate of the liquid precursor relative to the average mass flow rate of the liquid precursor exceeding 10% over a first duration. Delivering the vaporized liquid precursor into the thin film deposition chamber includes operating the liquid precursor delivery unit under higher stability conditions. This higher stability includes one or more of the following: a second liquid precursor temperature at the liquid injection unit that is lower than the first liquid temperature; a second liquid pressure upstream of the injection unit that is higher than the first liquid pressure; and a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure. This higher stability ensures that the mass flow rate of the liquid precursor varies by less than 10% relative to an average mass flow rate during a second duration having the same duration as the first duration.

Description

Technical Field

[0001] The disclosed technology is generally related to semiconductor processing, and more specifically to liquid precursor injection equipment and methods for depositing thin films. Prior Technology

[0002] As the lateral dimensions of semiconductor devices continue to be scaled up, one of the vertical dimensions of semiconductor devices is correspondingly scaled up, including the thickness of functional thin films such as electrodes and dielectrics. Semiconductor manufacturing involves the deposition of various thin films throughout the process. Various techniques, including wet and dry deposition methods, can be used to deposit these thin films. Wet deposition methods include, for example, aerosol / spray deposition, sol-gel methods, and spin coating. Dry deposition methods include physical vapor deposition (PVD) based techniques, such as evaporation. Dry deposition methods also include precursor and / or chemical reaction based techniques, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). Summary of the Invention

[0003] In a first embodiment, a method of injecting a liquid precursor into a thin film deposition chamber includes atomizing the liquid precursor into atomized precursor droplets using a liquid injection unit, vaporizing the atomized precursor droplets into a vaporized liquid precursor in a vaporization chamber, and delivering the vaporized liquid precursor into the thin film deposition chamber. The liquid injection unit and the liquid precursor cause the liquid precursor delivery unit to change by more than 10% relative to the average mass flow rate of the liquid precursor during a first duration under relatively stable conditions, including a first liquid precursor temperature at the liquid injection unit, a first liquid precursor pressure upstream of the liquid precursor injection unit, and a first gas pressure downstream of the liquid precursor injection unit. Delivering the vaporized liquid precursor into the thin film deposition chamber includes operating the liquid precursor delivery unit under relatively stable conditions. This higher stability includes one or more of the following: a second liquid precursor temperature at the liquid injection unit that is lower than the first liquid precursor temperature; a second liquid pressure upstream of the injection unit that is higher than the first liquid pressure; and a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure. This higher stability ensures that the mass flow rate of the liquid precursor varies by less than 10% relative to an average mass flow rate during a second duration having the same duration as the first duration.

[0004] In a second embodiment, a method for delivering a liquid precursor into a thin-film deposition chamber includes providing a liquid precursor delivery unit configured to atomize the liquid precursor into atomized precursor droplets using a liquid injection unit, vaporizing the atomized precursor droplets into a vaporized liquid precursor in a vaporization chamber, and delivering the vaporized liquid precursor into the thin-film deposition chamber. The method further includes delivering the vaporized liquid precursor into the thin-film deposition chamber under lower stability conditions, the lower stability conditions including a first liquid precursor temperature at the liquid injection unit, a first liquid precursor pressure upstream of the liquid precursor injection unit, and a first gas pressure downstream of the liquid precursor injection unit. The method further includes detecting a change in the mass flow rate of the liquid precursor relative to an average mass flow rate greater than 10% during a first duration. The method further includes delivering the vaporized liquid precursor into the thin film deposition chamber under a higher stability condition. This higher stability condition includes one or more of the following: a second liquid precursor temperature at the liquid injection unit that is lower than the first liquid precursor temperature; a second liquid precursor pressure upstream of the injection unit that is higher than the first liquid precursor pressure; and a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure. This higher stability condition ensures that the mass flow rate of the liquid precursor varies by less than 10% relative to an average mass flow rate during a second duration having the same duration as the first duration.

[0005] In a third embodiment, an apparatus for delivering a liquid precursor into a thin film deposition chamber includes a liquid precursor delivery system configured to deliver a vaporized liquid precursor into the thin film deposition chamber. The liquid precursor delivery system includes: a liquid injection unit configured to atomize the liquid precursor into atomized precursor droplets; a mixing region configured to receive the atomized precursor droplets from the liquid injection unit and form a mixture comprising the atomized precursor droplets and a carrier gas; and a vaporization chamber configured to receive the mixture and vaporize the atomized precursor droplets in the mixture to form the vaporized liquid precursor. The device further includes a liquid precursor delivery stability control system comprising one or more of the following: an injection unit temperature control system configured to sense and control the temperature of a liquid precursor at the liquid injection unit before it is introduced into the mixing region; a carrier gas temperature control system configured to sense and control the temperature of a carrier gas before it is introduced into the mixing region; a liquid propulsion pressure control system configured to sense and control the pressure of a liquid precursor upstream of the liquid precursor injection unit; and a downstream gas pressure control system configured to sense and control the gas pressure downstream of the liquid precursor injection unit. Simple Explanation of the Diagram

[0006] Figure 1A illustrates a thin film deposition system configured according to an embodiment to deliver a vaporized liquid precursor into a thin film deposition chamber.

[0007] Figure 1B illustrates the thin film deposition chamber of the thin film deposition system illustrated in Figure 1A according to an embodiment.

[0008] Figure 2 illustrates a liquid precursor delivery unit according to an embodiment for delivering a vaporized liquid precursor into a thin film deposition chamber.

[0009] Figures 3A and 3B illustrate an exemplary liquid precursor injection unit configured according to an embodiment to atomize a liquid precursor into atomized precursor droplets.

[0010] Figure 4 illustrates one method of delivering a liquid precursor into a thin film deposition chamber according to an embodiment.

[0011] Figure 5 illustrates a liquid precursor delivery stability control system according to an embodiment for controlling the delivery of a vaporized liquid precursor into a thin film deposition chamber.

[0012] Figures 6A to 6C illustrate thin film deposition procedures that can be implemented according to the liquid precursor delivery method and system of the embodiments.

[0013] Figure 7 illustrates an experimental graph showing the time-varying mass flow rate of a liquid precursor introduced into a thin film deposition chamber in a pulsed mode using a liquid precursor delivery method according to an embodiment. Implementation

[0014] Cyclic deposition processes such as atomic layer deposition (ALD) can provide relatively conformal conductive and insulating films with high uniformity on relatively high aspect ratio (e.g., 2:1) structures. While generally less conformal and uniform compared to ALD, films deposited using continuous deposition processes such as chemical vapor deposition (CVD) can offer higher productivity and lower costs. ALD and CVD can be used to deposit a wide variety of films, including, to name a few, elemental metals, semiconductors (e.g., Si, III-V group metals), dielectrics (e.g., SiO₂, AlN, HfO₂, ZrO₂), rare earth oxides, conductive oxides and oxides (e.g., TiN, IrO₂), ferroelectrics (e.g., PbTiO₃, LaNiO₃), superconductors (e.g., YBa₂Cu₃O₇₇ₓ), and chalcogenides (e.g., GeSbTe).

[0015] In precursor- or chemical reaction-based thin film deposition techniques (such as CVD and ALD processes), a precursor is delivered to a reactor and transported therein to a heated substrate to deposit a thin film. While gaseous precursors with high vapor pressures (e.g., >0.1 Torr) may be relatively easy to control, not all precursors are gaseous at atmospheric pressure and ambient temperature. Many precursors are available in liquid form. Precisely delivering liquid precursors into a reactor chamber is relatively more difficult to control than delivering gaseous precursors, and this, in turn, makes it more difficult to control the composition, nanostructure, and uniformity of the resulting thin film using liquid precursors. Therefore, there is a need to improve the delivery of liquid precursors into a reactor chamber to improve the control of the resulting thin film deposition characteristics (to name just a few, such as growth rate, intra-substrate uniformity, inter-substrate uniformity, surface morphology, and film density).

[0016] In some conventional precursor-based or chemical reaction-based thin film deposition techniques based on liquid precursors, a bubbler technique can be used. In a bubbler technique, a liquid precursor is stored in a bubbler (typically a stainless steel tank), and an inert carrier gas (e.g., Ar, He, or N₂) is introduced into the liquid to induce bubbling. The precursor vapor saturates the atmosphere in the bubbler and thus introduces the generated vapor onto the substrate surface. The delivery of reactants in these techniques depends on parameters including the temperature of the bubbler, the carrier gas flow rate, and the pressure above the liquid surface. While bubbler-based techniques can work satisfactorily with some liquid precursors, they may not be suitable for precursors with relatively low vapor pressures. This is because, although heating the bubbler is a practical way to increase the vapor pressure inside the tank, the maximum temperature to which the bubbler can be heated is limited to the decomposition temperature of the precursor. However, many liquid precursors have a relatively low decomposition temperature. Therefore, bubbler-based technology may be impractical for precursors with a relatively narrow temperature window (e.g., less than about 150°C, 100°C, or 50°C between the temperature at which the vapor pressure is high enough for practical (e.g., > 0.1 Torr) application and the temperature at which the precursor decomposes). Thus, bubbler-based technology may be limited to techniques that stabilize precursors at relatively high temperatures.

[0017] To overcome the limitations of bubbler-based liquid precursor delivery methods, the systems and methods described herein employ a direct liquid injection technique. As used herein, the term direct liquid injection (DLI) refers to a technique that feeds reactants into a deposition zone using a liquid precursor delivery unit (e.g., a syringe). Unlike other techniques such as bubbler techniques, in DLI-based techniques, the liquid precursor remains in liquid form until it enters an injection point in a low-pressure deposition chamber under vacuum. Even for precursors with a relatively narrow temperature window between the temperature at which the vapor pressure is sufficiently high for practical use (e.g., >0.1 Torr) and the temperature at which the precursor decomposes, DLI-based techniques still achieve precise control of the liquid mass flow rate. According to some embodiments disclosed herein, the temperature window for using the precursor by the liquid precursor delivery method and system can be less than one of 150°C, 100°C, 50°C, 25°C, or any of these values.

[0018] In some DLI-based technologies, the liquid precursor passes through an evaporation chamber where it is vaporized, while in others, the precursor arrives at the surface of a heated substrate in a liquid state (e.g., in the form of atomized liquid precursor droplets), where it is then vaporized before decomposition. If the precursor is still in a liquid phase when it reaches the substrate, the deposition method may be referred to as spray or aerosol pyrolysis, depending on the droplet generation method. Some spray / aerosol pyrolysis processes may be referred to as atmospheric pressure CVD because evaporation typically occurs near the substrate, which is heated to a high temperature. Advantages of DLI-based technologies include the relatively low temperature (e.g., room temperature) of the liquid precursor, which allows the use of precursors with low thermal stability and low vapor pressure.

[0019] The inventors have recognized that some conventional liquid delivery systems and methods can suffer from mass flow rate instability of the liquid precursor. Without being bound by any theory, the inventors have found that one cause of mass flow rate instability can be associated, in particular, with unintentional or excessive vaporization of the liquid precursor at or near a conventional valve or syringe, upstream of the injection point, or before it is injected into a low-pressure region (e.g., a vaporization chamber) at the injection point. When delivered by a conventional valve or syringe, the liquid precursor is intended to remain in the liquid phase until the injection point. However, the inventors have found that unintentional vaporization of the liquid precursor can occur extensively upstream of the injection point. Unintentional vaporization upstream of the injection point can occur in part because the liquid precursor can be heated to near a vaporization temperature at the injection point, and / or because the gas pressure downstream of the valve or syringe can be substantially lower than the vaporization pressure during deposition. Therefore, unintentional vaporization of the liquid precursor can occur extensively upstream of the injection point. Vaporization of the liquid precursor upstream of the injection point can lead to cavitation or bubbles, which in turn can cause instability in the mass flow rate of the liquid precursor used to deposit thin films in a thin film deposition chamber. To address these and other needs, the system and method disclosed herein deliver liquid precursors into a thin film deposition chamber with enhanced stability and repeatability of the liquid precursor mass flow rate. [A thin film deposition system configured for liquid precursor injection] []

[0020] Figure 1A illustrates a thin film deposition system configured to deliver a vaporized liquid precursor to a thin film deposition chamber according to an embodiment. The thin film deposition system 100 includes a liquid precursor delivery unit 112 configured to receive one or more liquid precursors from a liquid precursor panel 108. The liquid precursor delivery unit 112 is further configured to receive a carrier gas, such as hydrogen or an inert gas (such as Ar or N₂), through a carrier gas line 114, the flow rate of which is controlled by a mass flow controller 114a. The liquid precursor delivery unit 112 is configured to output one or more vaporized liquid precursors to a thin film deposition chamber 104. The thin film deposition chamber 104 is configured to receive vaporized liquid precursors through one or more liquid precursor inlet lines 118, and is further configured to receive one or more gaseous precursors, such as oxidants like O2 or NH3, from a gas panel 116 through one or more gaseous precursor inlet lines 120. The flow rates of these gaseous precursors are controlled by a mass flow controller 120a.

[0021] The liquid panel 108 includes one or more liquid precursor source units 110-1, 110-2, ..., 110-n, which in turn include liquid tanks 110a-1, 110a-2, ..., 110a-n configured to hold their respective liquid precursors. The liquid tanks 110a-1, 110a-2, ..., 110a-n are connected to each of the actuating gas lines 110b-1, 110b-2, ..., 110b-n and the liquid delivery lines 110c-1, 110c-2, ..., 110c-n. Each of the liquid flow meters (LFM) 110d-1, 110d-2, ..., 110d-n is installed in the flow path of the liquid delivery lines 110c-1, 110c-2, ..., 110c-n between the liquid tanks 110a-1, 110a-2, ..., 110a-n and the liquid precursor delivery unit 112.

[0022] In the illustrated embodiment, multiple liquid precursors are depicted being introduced into a common liquid precursor delivery unit 112. However, the configuration is not limited to this, and in other configurations, there may be a plurality of liquid precursor delivery units 112, each dedicated to a specific liquid precursor. Furthermore, a single carrier gas line 114 is depicted connected to the liquid precursor delivery unit 112. However, the configuration is not limited to this, and there may be a plurality of carrier gas lines 114, each connected to a dedicated liquid delivery unit 112, such that each liquid delivery unit 112 receives a dedicated liquid precursor and a dedicated carrier gas (e.g., FIG. 2).

[0023] Each of the liquid precursor source units 110-1, 110-2, ..., 110-n can be operated qualitatively in a similar manner. Referring to liquid precursor source unit 110-1 as an example, a propellant gas (e.g., hydrogen or an inert gas such as helium, argon, or nitrogen) flows from the propellant gas line 110b-1 into the liquid tank 110a-1 through a gas mass flow controller (not shown). The propellant gas pushes the liquid precursor out of the liquid tank 110a-1, and the liquid delivery line 110c-1 delivers the liquid precursor pushed out of the liquid tank 110a-1 to the liquid precursor delivery unit 112.

[0024] Figure 1B illustrates a thin film deposition chamber of a thin film deposition system according to one embodiment (e.g., the thin film deposition system 100 described above with respect to Figure 1A). The thin film deposition chamber 104 includes a chamber housing 111 configured to hermetically seal the chamber under vacuum.

[0025] The lower portion of the thin film deposition chamber 104 includes a support 124 having a top surface 124s configured for mounting a substrate 117 thereon. The support 124 can be heated to a programmed temperature by a heater 115. In some configurations, the support 124 can rotate about a rotation axis D to improve film uniformity. Rotation can occur relative to a central axis. A vacuum pump (not shown) connected to the thin film deposition chamber 104 via an outlet 128 is configured to evacuate the gas from the thin film deposition chamber 104. The upper portion of the thin film deposition chamber 104 includes a gas distribution plate or a showerhead 113 with a plurality of openings to spray a gas mixture onto the substrate 117.

[0026] One or more liquid precursor inlet lines 118 are configured to deliver vaporized liquid precursors from liquid precursor delivery unit 112, and one or more gaseous precursor inlet lines 120 are configured to deliver respective gaseous precursors (e.g., oxidants) from gas panel 116, connected to spray head 113. One or more mass flow meters 132 may be placed in the paths of liquid precursor inlet lines 118 and gaseous precursor inlet lines 120 to measure the mass flow rates of vaporized liquid precursors and gaseous precursors. A liquid precursor delivery stability control system 500 (FIG. 5) can sense changes in the mass flow rate of one of the vaporized liquid precursors to initiate a method for delivering liquid precursors under higher stability conditions according to the embodiments disclosed herein. For example, when the detected mass flow rate of (a number of) vaporized liquid precursors changes more than a manufacturing tolerance (e.g., 10%) relative to the average mass flow rate of one of the liquid precursors during a first duration, the liquid precursor delivery stability control system 500 may trigger method 400 according to one embodiment (Figure 4). [Liquid precursor delivery system] []

[0027] Figure 2 illustrates a liquid precursor injection system according to an embodiment for delivering a vaporized liquid precursor into a thin film deposition chamber (e.g., the thin film deposition chamber described above with respect to Figure 1B). The liquid precursor injection system 200 includes a liquid precursor delivery unit 112. The liquid precursor delivery unit 112 includes a liquid injection unit 204 configured to receive a liquid precursor in a liquid phase from a liquid precursor source unit 110. The liquid precursor source unit 110 includes a liquid tank 110a in which a liquid precursor 228 is stored. A propellant gas line 110b is connected to the liquid tank 110a via a pressure regulator 224. The liquid delivery line 110c is connected to the liquid injection unit 204 configured to atomize the liquid precursor 228. As described herein, atomization refers to a process that forms a spray of liquid precursor droplets from the liquid precursor. The atomized droplets may have an average diameter, for example, from about 1 μm to 100 μm. The droplets have a high surface area to volume ratio and are optimized for rapid evaporation into a vaporized liquid precursor.

[0028] In operation, to deliver the liquid precursor 228 out of the liquid tank 110a, a propellant gas (e.g., hydrogen or an inert gas such as helium, argon, or nitrogen) is supplied to the liquid tank 110a via a propellant gas line 110b, thereby displacing the liquid precursor 228 from the liquid tank 110a. The gas flow through the propellant gas line 110b can be regulated by a pressure regulator 224. Therefore, the displaced liquid precursor is delivered to the liquid injection unit 204 via the liquid delivery line 110c.

[0029] The liquid precursor delivery unit 112 additionally includes a carrier gas valve 208, configured to receive a carrier gas through a carrier gas line 114. This carrier gas can be hydrogen or an inert gas (such as helium, argon, or nitrogen). A carrier gas heater 220 can be positioned within the carrier gas line 114 to regulate the temperature of the carrier gas delivered to the carrier gas valve 208. The liquid precursor delivery unit 112 additionally includes a mixing region 212, downstream of the liquid injection unit 204 and the carrier gas valve 208, configured to mix atomized liquid precursor droplets and the carrier gas to form an atomized liquid precursor mixture. The liquid injection unit 204 and the carrier gas valve 208 are configured to inject atomized precursor droplets and carrier gas into the mixing region 212, respectively. In some configurations, the trajectories of the atomized precursor droplets ejected from the liquid injection unit 204 and the carrier gas ejected from the carrier gas valve 208 may intersect at a mixing point within the mixing region 212, thereby efficiently forming an atomized liquid precursor mixture by mixing the atomized precursor droplets and the carrier gas before vaporization.

[0030] Subsequently, an atomized liquid precursor mixture, formed from atomized precursor droplets and a carrier gas formed in mixing region 212, is introduced into a vaporization chamber 216. The vaporization chamber 216 is configured to vaporize the atomized precursor droplets in the atomized liquid precursor mixture to form a vaporized liquid precursor mixture containing vaporized liquid precursor and carrier gas. The vaporization chamber 216 may have a volume of approximately 1 liter to 3 liters. The vaporization chamber 216 includes a vaporization component, such as a heater. For example, the vaporization of the atomized precursor droplets can be achieved partly by heating the walls of the vaporization chamber 216. The walls of the vaporization chamber 216 can be heated to, for example, a temperature such that the atomized precursor droplets are heated to a temperature between the vaporization temperature and decomposition temperature of the liquid precursor at atmospheric pressure. For example, for a liquid precursor having a vaporization temperature of 200°C and a decomposition temperature of 250°C at atmospheric pressure, the vaporization chamber 216 can be heated to a temperature between 200°C and 250°C. The vaporization chamber 216 is configured to deliver the vaporized liquid precursor mixture thus formed into the thin film deposition chamber 104 through the liquid precursor inlet 118 and further through a spray head 113, as described above with respect to Figures 1A and 1B. One or more gaseous precursors (e.g., oxidant from the gas panel 116) are delivered through the gas precursor inlet 120, which is also connected to the spray head 113, as described above with respect to Figures 1A and 1B.

[0031] Referring again to Figure 2, when connected to a thin film deposition chamber 104 under vacuum or a thin film deposition chamber pressure, the mixing region 212 and the vaporization chamber 216 can be configured to operate at a local pressure higher than the deposition chamber pressure. This higher local pressure can be achieved by designing the shape of the internal volumes of the mixing region 212 and / or the vaporization chamber 216 to limit their isoconductivity. For example, one or both of the mixing region 212 and the vaporization chamber 216 can be contained in an elongated section extending in a vertical direction perpendicular to the plane of the spray head 113, creating a pressure gradient in the vertical direction. For example, one or both of the mixing region 212 and / or the vaporization chamber 216 can have an aspect ratio between a length in the vertical direction and a width or diameter in the horizontal direction greater than a value within a range defined by 2:1, 4:1, 6:1, 8:1, 10:1, or any of the equivalents. Alternatively, the mixing region 212 and / or the vaporization chamber 216 may be partially obstructed by a conduction-limiting orifice for evacuation. Alternatively, one or both of the mixing region 212 and the vaporization chamber 216 may include a continuously adjustable conduction control member (e.g., a pressure regulator or a butterfly valve and the like) at their lower portion, such that the local pressure therein is higher than the pressure in the deposition chamber. For example, the conduction control member may be positioned between the mixing region 212 and the vaporization chamber 216, and / or between the vaporization chamber 216 and the thin film deposition chamber 104, for example, upstream of the spray head 113.

[0032] In the illustrated embodiment, the mixing region 212 and the vaporization chamber 216 are depicted as separate chambers. However, the configuration is not limited to this, and in other configurations, the mixing region 212 may form part of the vaporization chamber 216, having different shapes and sizes of internal volumes (e.g., an elongated volume as described above). In some other configurations, the mixing region 212 may be omitted, and the atomized liquid precursor and carrier gas may be directly introduced into the vaporization chamber 216.

[0033] Referring again to FIG. 2, the liquid injection unit 204 may include a suitable component configured to atomize a liquid precursor into atomized precursor droplets or aerosols. In one embodiment, the liquid injection unit 204 may include a metering valve. FIG. 3A and FIG. 3B illustrate an exemplary liquid precursor injection unit 204 according to an embodiment, including a metering valve 304 configured to atomize a liquid precursor into atomized precursor droplets. The depicted example of the metering valve 304 is similar to a PICO™ valve manufactured by Nordson EFD LLC, the specifications and design of which are incorporated herein by reference in their entirety. FIG. 3A depicts the metering valve 304 in a closed state and FIG. 3B depicts the metering valve 304 in an open state. The metering valve 304 includes an inlet 302 connected to a liquid delivery line 110c (FIG. 2) for receiving liquid precursor 228 from the liquid precursor source unit 110, and an outlet 320 connected to a mixing region 212 (FIG. 2). Metering valve 304 includes a lever 308 configured to be driven by a piezoelectric actuator to move up and down as indicated by the arrow. Lever 308 has a distal end to which a vertical rod 312 is movably connected. Movement of lever 308 causes a corresponding vertical movement of rod 312, as indicated by the arrow. At the bottom end of rod 312, a hemispherical sealing ball 316 formed of a wear-resistant ceramic is disposed. A ceramic valve seat 318 (also referred to as a nozzle plate) is disposed below the sealing ball 316. The ceramic valve seat 318 has an opening smaller than the diameter of the sealing ball 316. The opening may have a diameter, for example, from 50 μm to 500 μm. For the illustrated example of metering valve 304, the opening of valve seat 318 may represent an injection point. As described herein, the injection point defines a region within a liquid injection unit 204 where liquid precursor 228 is atomized into atomized precursor droplets. The injection point also defines a point that divides the upstream portion of the metering valve 304 where the liquid precursor is in a liquid state and the downstream portion of the metering valve 304 exposed to a low-pressure area (e.g., mixing region 212).

[0034] In operation, as depicted in Figure 3A, when the sealing ball 316 is seated on the valve seat 318, the opening or injection point is closed by the sealing ball 316, thereby preventing the liquid precursor 228 from being injected from the metering valve 304. On the other hand, as depicted in Figure 3B, when the sealing ball 316 is lifted off the valve seat 318, the opening or injection point is opened by the sealing ball 316, thereby allowing the liquid precursor 228 to be injected or ejected from the metering valve 304.

[0035] Other embodiments of the liquid injection unit 204 (FIG. 2) are feasible. According to one alternative embodiment, the injection unit 204 (FIG. 2) may include a mass flow controller comprising a controllable valve, wherein changing the position of the valve results in a variation of the liquid flow rate. According to yet another alternative embodiment, the injection unit 204 may include a mass flow meter that does not include a controllable valve, wherein changing the driving pressure applied thereto results in a variation of the liquid flow rate. [Liquid Injection Method and Control System] []

[0036] Figure 4 illustrates a method for delivering a liquid precursor into a thin film deposition chamber according to an embodiment. Figure 5 illustrates a liquid precursor delivery stability control system according to an embodiment for controlling the delivery of a vaporized liquid precursor into a thin film deposition chamber. Hereinafter, the method 400 for delivering the liquid precursor (Figure 4) is described in conjunction with the control system 500 (Figure 5).

[0037] Referring to Figure 5, a liquid precursor delivery control system 500 for controlling the delivery of a vaporized liquid precursor to a thin film deposition chamber includes a liquid propulsion pressure control system 510, an injection unit temperature control system 520, a carrier gas temperature control system 530, and a downstream pressure control system 540, all communicatively coupled to a central control unit 550. The liquid propulsion pressure control system 510, which may be located upstream of the liquid injection unit 204 (Figure 2), is configured to control the liquid precursor propulsion pressure in the liquid delivery line 110c (Figure 2) upstream of the liquid precursor injection unit 204 (Figure 2) using a liquid pressure sensing element 514 and a liquid pressure control element 518, which are communicatively coupled to each other. The injection unit temperature control system 520, which may be located at or upstream of the liquid injection unit 204 (Figure 2), is configured to control the liquid precursor temperature at or above the liquid injection unit 204 (Figure 2) using a liquid temperature sensing element 524 and a liquid temperature control element 528, which are communicatively coupled to each other. A carrier gas temperature control system 530, which may be located at or upstream of the carrier gas valve 208 (FIG. 2), is configured to control the carrier gas temperature at or above the carrier gas valve 208 (FIG. 2) using a carrier gas temperature sensing element 534 and a carrier gas temperature control element 538 that are communicatively coupled to each other. A downstream pressure control system 540, which may be located downstream of the liquid injection unit 204 (FIG. 2), is configured to control the gas pressure downstream of the liquid injection unit 204 (FIG. 2) using a gas pressure sensing element 544 and a gas pressure control element 548 that are communicatively coupled to each other. Each of the liquid pressure sensing element 514 and the gas pressure sensing element 544 may include a suitable pressure sensor, such as a pressure gauge, a transducer, and the like. Each of the liquid temperature sensing element 524 and the carrier gas temperature sensing element 534 may include a suitable temperature sensor, such as a thermocouple, a thermistor, a resistance temperature detector, and the like. Each of the liquid pressure control component 518 and the gas pressure control component 548 may include a pressure regulator, a control valve, and the like, which may be controlled by a suitable controller circuit and / or algorithm. Each of the liquid temperature control component 528 and the carrier gas temperature control component 538 may include a heater and / or a cooler, which may be controlled by an internal or external controller circuit and / or algorithm.

[0038] Referring again to Figure 5, the liquid-driven pressure control system 510, the injection unit temperature control system 520, the carrier gas temperature control system 530, and the downstream pressure control system 540, as well as their respective sensing and control components included therein, are communicatively coupled to each other and communicatively coupled to a central control or processing unit 550. The central control or processing unit 550 includes a processor, memory, and storage devices, which are configured to store and execute executable algorithms for communicating with and at least partially automatically controlling the liquid-driven pressure control system 510, the injection unit temperature control system 520, the carrier gas temperature control system 530, and the downstream pressure control system 540, thereby automatically or computationally implementing part or all of method 400. For example, upon detecting a mass flow rate variation exceeding a predefined manufacturing tolerance, one or more of the liquid-driven pressure control system 510, the injection unit temperature control system 520, the carrier gas temperature control system 530, and the downstream pressure control system 540 can be activated. The flow rate variation can be detected by, for example, a mass flow meter 132 (Figure 1B). When a mass flow rate variation exceeding the manufacturing tolerance is detected, one or more of the liquid pressure control component 518, liquid temperature control component 528, carrier gas temperature control component 538, and gas pressure control component 548 may, in conjunction with the central control unit 550, at least partially automatically or computationally adjust the liquid driving pressure in the liquid delivery line 110c (Figure 2), the liquid precursor temperature at or above the liquid injection unit 204 (Figure 2), the carrier gas temperature at or above the carrier gas valve 208 (Figure 2), and the gas pressure downstream of the liquid injection unit 204 (Figure 2).

[0039] Referring to Figures 4 and 5, a method 400 for delivering a liquid precursor into a thin film deposition chamber includes providing a liquid precursor delivery unit 112 (Figure 2) configured to deliver a vaporized liquid precursor 228 (Figure 2) into a thin film deposition chamber 104 (Figure 2). As described above, the liquid precursor delivery unit 112 includes a liquid injection unit 204 (Figure 2) configured to atomize the liquid precursor into atomized precursor droplets and a vaporization chamber 216 (Figure 2) configured to vaporize the atomized precursor droplets before delivery into the thin film deposition chamber 104 (Figure 2). The method further includes delivering a vaporized liquid precursor into a thin film deposition chamber 104 using a liquid precursor delivery unit 112, wherein delivering the vaporized liquid precursor includes: atomizing a liquid precursor 228 into atomized precursor droplets using a liquid injection unit 204 and vaporizing the atomized precursor droplets into vaporized liquid precursor using a vaporization chamber 216. The liquid precursor delivery unit 112 and the liquid precursor 228 are such that when the liquid precursor delivery unit 112 is operated under lower stability conditions, the mass flow rate of one of the liquid precursors varies more than a manufacturing tolerance relative to the average mass flow rate of one of the liquid precursors 228 during a first duration.

[0040] The lower stability conditions that cause this variation include one or more of the following: a first liquid precursor temperature (T PL1) at liquid injection unit 204 (FIG. 2), a first liquid precursor pressure (P PL1) upstream of liquid injection unit 204, and a first gas pressure (P PG1) downstream of liquid injection unit 204. The inventors have discovered that this variation in mass flow rate can lead to manufacturing inhomogeneities, including variations in thickness, composition, and film quality (such as density across substrates and across different substrates).

[0041] The inventors have discovered that operating the 420 liquid precursor delivery unit 112 under higher stability conditions causes the mass flow rate of the liquid precursor to change less than a manufacturing tolerance relative to an average mass flow rate during a second duration having the same duration as the first duration. In some embodiments, operating the 420 liquid precursor delivery unit 112 under higher stability conditions includes one or more of the following: setting or reducing the temperature of the liquid precursor 228 by 424 to a second liquid precursor temperature (TPL2) at the liquid injection unit 204 (FIG. 2) below the first liquid precursor temperature (TPL1); setting or increasing the pressure of the liquid precursor 228 by 426 to a second liquid precursor pressure (PPL2) upstream of the injection unit above the first liquid precursor pressure (PPL1); and setting or increasing the gas pressure downstream of the liquid injection unit 204 by 428 to a second gas pressure (PPG2) downstream of the liquid injection unit 204 above the first downstream pressure (PPG1).

[0042] Referring again to Figure 4, the inventors have discovered that operating the 420 liquid precursor delivery unit 112 (Figure 2) under higher stability conditions according to the embodiments disclosed herein advantageously delivers the liquid precursor 228 into the thin film deposition chamber 104 (Figure 2) with enhanced stability and repeatability. This enhanced stability and repeatability are achieved, in particular at least in part, by maintaining the liquid precursor in a liquid phase and preventing vaporization of the liquid precursor upstream of the injection point, as described above. Advantageously, method 400 achieves significant suppression of vaporization of the liquid precursor upstream of the injection point, which in turn suppresses cavitation or bubble formation, thereby achieving enhanced stability of the vaporized precursor used for depositing the thin film in the thin film deposition chamber 104 (Figure 2).

[0043] This can advantageously maintain the enhanced stability and repeatability of the liquid precursor's mass flow rate, even though the liquid precursor is heated to or near its vaporization temperature at the injection point, and / or the gas pressure downstream of the injection point is substantially lower than the vaporization pressure during deposition. As described herein, the vaporization temperature refers to a temperature at which the vapor pressure of the liquid precursor is sufficient for deposition, for example, a temperature at which the vapor pressure is greater than one in a range defined by about 0.1 Torr, 0.2 Torr, 0.5 Torr, 1 Torr, or any of the equivalents. The temperature of the liquid precursor 228 can be defined by its proximity to the vaporization temperature and / or decomposition temperature. According to various embodiments, the liquid precursor delivery unit 112 (FIG. 2) or the liquid precursor 228 (FIG. 2) at the injection point therein may be within a range defined by + / - 50°C, + / - 30°C, + / - 20°C, + / - 10°C, or any equivalent of the vaporization temperature of the liquid precursor 228, or within a range defined by 50°C, 30°C, 20°C, 10°C, or any equivalent of the decomposition temperature of the liquid precursor. Downstream of the injection point (e.g., mixing region 212 (FIG. 2), vaporization chamber 216 (FIG. 2), and / or thin film deposition chamber 104) The pressure (in Figure 2) can be 0.01 Torr to 0.2 Torr, 0.2 Torr to 0.4 Torr, 0.4 Torr to 0.6 Torr, 0.6 Torr to 0.8 Torr, 0.8 Torr to 1.0 Torr, 1.0 Torr to 1.5 Torr, 1.5 Torr to 2.0 Torr, 2.0 Torr to 2.5 Torr, 2.5 Torr to 3.0 Torr, 3.0 Torr to 4.0 Torr, 4.0 Torr to 5.0 Torr, 5.0 Torr to 6.0 Torr, 6.0 Torr to 7.0 Torr, 7.0 Torr to 8.0 Torr, 8.0 Torr to 9.0 Torr, 9.0 Torr to 10.0 Torr, 10.0 Torr to 11.0 Torr, 11.0 Torr to 12.0 Torr, or a pressure within the range defined by any of these equivalent values.

[0044] Referring again to Figure 4, enhanced stability and repeatability can be quantified by the variability of the mass flow rate, which can be measured by a mass flow meter 132 (Figure 1B) relative to a manufacturing tolerance. Advantageously, operating the 420 liquid precursor delivery unit 112 under higher stability conditions enables the liquid precursor mass flow rate to be maintained within a manufacturing tolerance. The manufacturing tolerance of the liquid precursor mass flow rate may vary depending on the application. For example, for dielectric and conductive films used in the manufacture of memory and logic semiconductor wafers for advanced technology nodes (e.g., < 130 nm), manufacturing tolerances may specify that the mass flow rate during a duration defined within a range of 1 ms, 5 ms, 10 ms, 20 ms, 50 ms, 100 ms, 200 ms, 500 ms, 1 second, 2 seconds, 5 seconds, 10 seconds, 20 seconds, 50 seconds, 100 seconds, 200 seconds, 500 seconds, 1000 seconds, 2000 seconds, 5000 seconds, 10,000 seconds, 100,000 seconds, 1,000,000 seconds, or any equivalent value thereof, does not change by more than 1%, 2%, 5%, 10%, 20%, or any equivalent value thereof relative to the average mass flow rate of the liquid precursor. For example, the duration may correspond to the total exposure time of hundreds or thousands of wafer processes between consecutive preventative maintenance operations of a thin film deposition system. For continuous precursor exposures such as in chemical vapor deposition (CVD), the duration may represent an uninterrupted duration. For cyclic precursor exposures such as in atomic layer deposition (ALD), the duration may be the duration of a single pulse or the sum of the durations of a plurality of depositions. In some embodiments, the duration may exclude transient effects such as initial spikes or dips when the liquid precursor delivery unit 112 (FIG. 2) is initially started.

[0045] Referring again to FIG4, in some embodiments, operating the liquid precursor delivery unit 112 (FIG. 2) under higher stability conditions includes setting or lowering the temperature (T PL) of the liquid precursor 228 by 424 to a second liquid precursor temperature (T PL2) at the liquid injection unit 204 that is lower than the first liquid precursor temperature (T PL1) under low stability conditions. T PL2 can be achieved in part by using the injection unit temperature control system 520 (FIG. 5) at the liquid injection unit 204 (FIG. 2) or by combining it with the carrier gas temperature control system 530 (FIG. 5) to lower the temperature of the liquid precursor 228 (FIG. 2) by 424 to T PL2.

[0046] Referring to Figure 5, the injection unit temperature control system 520 is configured to actively control the temperature of the liquid precursor before it is atomized into the mixing region 212 using a liquid temperature sensing component 524 and a liquid temperature control component 528. When, for example, a mass flow rate variation exceeding manufacturing tolerances is detected using a mass flow meter 132 (Figure 1B), the liquid temperature sensing component 524 and the liquid temperature control component 528 can, in conjunction with the central control unit 550, at least partially automatically or computationally adjust the temperature of the liquid precursor at or above the injection point within the liquid injection unit 204 (Figure 2).

[0047] The liquid temperature control component 528 may include an active cooling component for reducing the temperature (T PL) of the liquid precursor 228 at the injection unit 204 (FIG. 2) before it is atomized into the mixing region 212 (FIG. 2). According to various embodiments, one or both of the first and second liquid precursor temperatures (T PL1, T PL2) upstream of the injection point (e.g., immediately upstream) can be set or reduced to a value within a range defined by + / -50°C, + / -30°C, + / -20°C, + / -10°C, or any equivalent of the vaporization temperature of the liquid precursor 228 at atmospheric pressure, or within a range defined by 50°C, 30°C, 20°C, 10°C, or any equivalent of the decomposition temperature of the liquid precursor 228 (FIG. 2) at atmospheric pressure. By actively cooling, the temperature of the liquid precursor can advantageously be set or reduced from TPL1 to TPL2 within one of the following ranges: at least 5°C to 50°C, 5°C to 10°C, 10°C to 20°C, 20°C to 30°C, 40°C to 50°C, or any of these values. It will be understood that controlling TPL within these ranges is critical because, as discussed above, a TPL below these ranges may result in incomplete vaporization of the liquid precursor, while a TPL above these ranges may result in decomposition of the liquid precursor.

[0048] The inventors have discovered that, in some cases, cooling the liquid precursor as described herein can have unintentional negative consequences. For example, a lower liquid precursor temperature may result in lower atomization or precursor droplet formation efficiency and / or mixing efficiency in mixing region 212, and / or lower vaporization efficiency in vaporization chamber 216. To address these and other potential negative effects, in some embodiments, the reduced second liquid precursor temperature (T PL2) of the liquid precursor 228 can be compensated at least partially by heating the carrier gas and mixing the atomized precursor droplets formed from the cooled liquid precursor with the heated carrier gas in mixing region 212 (FIG. 2), as described below.

[0049] Referring to Figure 5, the carrier gas temperature control system 530 is configured to actively control the temperature (TCG) of the carrier gas before it is introduced into the mixing region 212 using a carrier gas temperature sensing element 534 and a carrier gas temperature control element 538. When, for example, a mass flow rate variation exceeding manufacturing tolerances is detected using a mass flow meter 132 (Figure 1B), the carrier gas temperature sensing element 534 and the carrier gas temperature control element 538, in conjunction with the central control unit 550, can at least partially automatically or computationally adjust the carrier gas temperature to heat and / or maintain it at a higher temperature at the carrier gas valve 208 above the mixing region 212 (Figure 2).

[0050] In these embodiments, the carrier gas valve 208 can be configured to actively control the temperature of the carrier gas before it is delivered to the mixing region 212. For example, the carrier gas temperature control system 530 may include an active heating element mounted at the carrier gas valve 208. The carrier gas temperature control system 530 may include, for example, a carrier gas temperature sensing element 534 configured to sense the temperature of the carrier gas upstream of the carrier gas valve 208, and a carrier gas temperature control element 538 including a heater that actively increases the temperature of the carrier gas before it is introduced into the mixing region 212. The temperature of the carrier gas can be heated from a lower carrier temperature (TCG1) under lower stability conditions to a value within a range defined by at least 5°C to 50°C, 5°C to 10°C, 10°C to 20°C, 20°C to 30°C, 40°C to 50°C, or any of these equivalents, to a higher carrier temperature (TCG2).

[0051] Advantageously, heating the carrier gas from T CG1 under lower stability conditions to T CG2 under higher stability conditions at least partially compensates for the cooling effect of the liquid precursor when it is atomized into mixing region 212 (FIG. 2). According to various embodiments, the temperature of the atomized precursor droplets formed by mixing the liquid precursor at the second liquid precursor temperature (T PL2) with the atomized liquid precursor mixture formed by heating the carrier gas at T CG2 can be substantially the same as the temperature of the atomized liquid precursor mixture formed by mixing the liquid precursor droplets formed at the first liquid precursor temperature (T PL1) under lower stability conditions with the carrier gas at T CG1 before heating. For example, the temperature variation of the atomized liquid precursor mixture in mixing region 212 between lower and higher stability conditions can be within one of the ranges defined as 5°C to 50°C, 5°C to 10°C, 10°C to 20°C, 20°C to 30°C, 40°C to 50°C, or any of these equivalent values. It will be understood that controlling the temperature of the atomized precursor mixture within these ranges can be critical, as lower temperatures may lead to incomplete vaporization of the liquid precursor, while higher temperatures may lead to decomposition of the liquid precursor.

[0052] Referring again to FIG4, in some embodiments, operating the liquid precursor delivery unit 112 (FIG. 2) under higher stability conditions includes setting or increasing the liquid pressure (P PL) of the liquid precursor 228 to a second liquid pressure (P PL2) upstream of the injection point in the injection unit 204, which is higher than the first liquid pressure (P PL1) upstream of the injection point in the liquid injection unit 204, representing a lower stability condition. The liquid pressure setting or increase of the liquid precursor 228 can be achieved using a liquid push pressure control system 510. In one embodiment, the pressure of the push gas (e.g., hydrogen or an inert gas such as helium, argon, or nitrogen) supplied to the liquid tank 110a (FIG. 2) via the push gas line 110b (FIG. 2) can be increased to increase the displacement pressure of the liquid precursor 228 from the liquid tank 110a. The increased push pressure in the push gas line 110b can be regulated by a pressure regulator 224 (FIG. 2). Therefore, the displacement liquid precursor 228 under P PL2 is delivered to the injection unit 204 through the liquid delivery line 110c.

[0053] Referring to Figure 5, the liquid propulsion pressure control system 510 is configured to actively control the P PL of the liquid precursor 228 (Figure 2) before it is atomized into the mixing region 212 (Figure 2) using a liquid pressure sensing component 514 and a liquid pressure control component 518. When, for example, a mass flow rate variation exceeding manufacturing tolerances is detected using a mass flow meter 132 (Figure 1B), the liquid pressure sensing component 514 and the liquid pressure control component 518 can, in conjunction with the central control unit 550, at least partially automatically or computationally adjust the liquid precursor pressure upstream of the liquid injection unit 204 (Figure 2) (e.g., at the liquid precursor source unit 110).

[0054] To controllably deliver the liquid precursor 228 to the injection unit 204 having P PL2, according to some embodiments, setting or increasing the P PL upstream of the liquid injection unit 204 includes regulating a liquid-driven gas at the liquid precursor source unit 110 (FIG. 2). The pressure regulator 224 is configured such that the liquid-driven pressure in the liquid delivery line 110c can be controlled within a range defined as 10 to 50 absolute pounds per square inch (psia), 10 to 15 absolute pounds per square inch, 15 to 20 absolute pounds per square inch, 20 to 25 absolute pounds per square inch, 25 to 30 absolute pounds per square inch, 30 to 35 absolute pounds per square inch, 35 to 40 absolute pounds per square inch, 40 to 45 absolute pounds per square inch, 45 to 50 absolute pounds per square inch, or any of these equivalent values, for example, between 14 absolute pounds per square inch and 30 absolute pounds per square inch, for example, 28 absolute pounds per square inch.

[0055] Referring again to FIG4, in some other embodiments, operating the liquid precursor delivery unit 112 under higher stability conditions includes setting or increasing the gas pressure (PPG) downstream of the injection unit 204 to a second gas pressure (PPG2) higher than the first gas pressure (PPG1). PPG2 can be achieved at least in part by limiting conduction in a region between the liquid injection unit 204 and the thin film deposition chamber 104 using the downstream pressure control system 540. For example, an increase in PPG can be achieved by limiting conduction to locally increase the PPG of one or both of the mixing region 212 and the vaporization chamber 216.

[0056] In some embodiments, a local increase in PPG can be achieved by elongating the volume of one or both of the mixing region 212 and the vaporization chamber 216 in a vertical direction perpendicular to the plane of the spray head 113, thereby creating a pressure gradient in the vertical direction. Elongating one or both of the mixing region 212 and the vaporization chamber 216 may involve elongating their respective volumes to have an aspect ratio between their length and width or diameter in the vertical direction, which is greater than a value within a range defined by 2:1, 4:1, 6:1, 8:1, 10:1, or any of the equivalents thereof. In some other embodiments, one or both of the mixing region 212 and the vaporization chamber 216 may include a continuously adjustable conductive control member (such as a pressure regulator or a butterfly valve or similar) at their lower portion, such that the local pressure therein is controlled to be higher than the gas pressure in the thin film deposition chamber 104 (FIG. 2).

[0057] Referring to Figure 5, the downstream pressure control system 540 is configured to actively control the liquid precursor downstream of the liquid injection unit 204 (e.g., in the mixing region 212 and / or the vaporization chamber 216) using the gas pressure sensing component 544 and the gas pressure control component 548. When, for example, a mass flow rate variation exceeding manufacturing tolerances is detected using the mass flow meter 132 (Figure 1B), the gas pressure sensing component 544 and the gas pressure control component 548 can, in conjunction with the central control unit 550, at least partially automatically or computationally adjust the downstream of the liquid injection unit 204 (e.g., in the mixing region 212 and / or the vaporization chamber 216).

[0058] According to various embodiments, during deposition, the total pressure in the thin film deposition chamber 104 can be a pressure within the range defined by 1.0 Torr to 3.0 Torr, 3.0 Torr to 5.0 Torr, 5.0 Torr to 7.0 Torr, 7.0 Torr to 10.0 Torr, or any equivalent thereof. Without a significant reduction in conductivity, P PG1 can be the same or different, and is a pressure within the range defined by 1.0 Torr to 3.0 Torr, 3.0 Torr to 5.0 Torr, 5.0 Torr to 7.0 Torr, 7.0 Torr to 10.0 Torr, or any equivalent thereof. Using the downstream pressure control system 540, the local pressure in one or both of the mixing zone 212 and the vaporization chamber 216 can be set or increased to a higher percentage relative to the thin film deposition chamber 104, for example, exceeding a percentage within a range defined by 10%, 20%, 50%, 100%, 200%, 500%, or any of the equivalent values, for example, a value within a range defined by 2.0 Torr to 3.0 Torr, 3.0 Torr to 5.0 Torr, 5.0 Torr to 7.0 Torr, 7.0 Torr to 9.0 Torr, 9.0 Torr to 12 Torr, or any of the equivalent values. [application] []

[0059] Methods and systems for delivering vaporized liquid precursors into a thin film deposition chamber can be implemented in various precursor-based deposition processes. Figures 6A to 6C illustrate thin film deposition processes in which liquid precursor delivery methods and systems according to embodiments can be implemented. Representative examples of thin film processes in which liquid precursor delivery according to embodiments can be implemented include chemical vapor deposition (Figure 6A), atomic vapor deposition (Figure 6B), and atomic layer deposition (Figure 6C). Figures 6A to 6C are schematic graphs depicting a precursor parameter on the y-axis and time on the x-axis. Precursor parameters may include, for example, a precursor flow rate, precursor partial pressure, or a chamber pressure attributable to precursor introduction. Figures 6A to 6C depict a first precursor 610 and a second precursor 620. One or both of the first and second precursors 610 and 620 may be liquid precursors, or one of them, other than the first and second precursors 610 and 620, may be a liquid precursor. For example, the first precursor 610 may be an oxidizing precursor (e.g., O2 or NH3) from the gas panel 116 (FIG. 2) and the second precursor may be a liquid precursor 228 (FIG. 2), for example, a metal precursor. One or both of the first and second precursors 610 and 620 may be introduced using a carrier gas. Although two precursors are shown for illustrative purposes only, it will be understood that more than two precursors may be present.

[0060] Figure 6A is a schematic diagram illustrating the time-varying parameters of precursors during the deposition of a thin film using a continuous deposition process (e.g., chemical vapor deposition (CVD)). The illustrated continuous deposition process includes the simultaneous or time-overlapping introduction of a first precursor 620 and a second precursor 610 into the thin film deposition chamber 104 (Figure 2).

[0061] Figure 6C schematically illustrates a graph showing the time-varying precursor parameters during the deposition of a thin film using a cyclic deposition process (e.g., atomic layer deposition (ALD)). The illustrated cyclic deposition procedure includes cyclically introducing a pulse of a first precursor 610, followed by a pulse of a second precursor 620. The exposure time or pulse time of each of the first and second precursors 610, 620 can be within a range of durations defined as approximately 0.1 seconds to 1 second, 1 second to 10 seconds, 10 seconds to 30 seconds, 30 seconds to 60 seconds, or any of these equivalent values. Cycle 310 can be repeated multiple times to deposit a desired thickness of the thin film. The pulses of the first precursor 610 and the second precursor 620 can be accompanied by or separated from a purge gas. The purge gas can be continuous or pulsed. Examples of purge gases that can be used include, but are not limited to, helium (He), argon (Ar), nitrogen (N2), hydrogen (H2), and mixtures thereof. In the illustrated example, the cycles of the first and second precursors 610 and 620 do not overlap in time. However, the example is not limited to this, and there may be partial overlap between cycles. In some embodiments, the purge pulses may be introduced continuously or as pulses separated from the pulses of the first and second precursors 610 and 620 into the thin film deposition chamber 104 (FIG. 2). In other embodiments, in the absence of purge gas, the pulses of the first precursor 610 and the second precursor 620 may be separated by pump evacuation.

[0062] Figure 6B schematically illustrates a graph showing the time-varying precursor parameters during the deposition of a thin film using a hybrid deposition process (e.g., atomic vapor deposition (AVD)). The illustrated hybrid deposition procedure includes cyclically introducing pulses of a second precursor 620 while continuously or in pulses spanning at least one pulse of the second precursor 620, introducing a first precursor 610. The exposure time or pulse time of the second precursor 620 and the first precursor 610 during pulsed deposition can be within a range of durations defined as approximately 0.1 seconds to 1 second, 1 second to 10 seconds, 10 seconds to 30 seconds, 30 seconds to 60 seconds, or any of these equivalent values. In the illustrated embodiment, the first precursor 610 spans multiple pulses of the second precursor. However, the examples are not limited to this, and the first precursor may partially or completely span only one pulse of the second precursor 620. One or both of the first precursor 610 and the second precursor 620 may be accompanied by a carrier or purge gas. The purging or carrier gas may be continuous or pulsed, and may include, but is not limited to, helium (He), argon (Ar), nitrogen (N2), hydrogen (H2), and mixtures thereof.

[0063] Methods and systems for delivering a liquid precursor into a thin film deposition chamber can be configured to use a liquid precursor comprising B, N, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Ge, As, Se, Sr, Y, Zr, Nb, Mo, Ru, Ag, Cd, Sn, Sb, Ba, Hf, Ta, W, Re, Ti, La, and Er, etc. A liquid precursor of a metal can be a metal halide or an organometallic compound, such as metal β-diketones, metal cyclopentadienes, metal alkoxides, metal alkanes, and metal alkylamides, depending on the organic complex associated with the metal. The liquid precursor can be a liquid precursor or a solid precursor dissolved in a solvent. The liquid precursor can be used to form metal oxides, metal nitrides, compound semiconductors, chalcogenides, fluorides, and elemental metals, as well as other compounds.

[0064] Figure 7 illustrates an experimental graph showing the measured mass flow rate of a liquid precursor introduced in a pulsed pattern using a delivery method according to an embodiment, varying over time. The y-axis represents the flow rate in standard cubic centimeters per minute (sccm), and the x-axis represents time (hour:minute:second). In the illustrated example, the pulses of the liquid precursor have a duration of approximately 60 seconds. For each pulse of the liquid precursor, after an initial transient spike corresponding to the moment the injection point of the liquid injection unit 204 (Figure 2) is opened, the mass flow rate remains highly constant within the pulse and is reproducible between pulses. As discussed above, for cyclic precursor exposures such as those illustrated, the duration defining a manufacturing tolerance can be the duration of a single pulse or the sum of the durations of multiple depositions. In the illustrated example, the duration excludes the initial spike when the liquid precursor delivery unit 112 (Figure 2) is initially activated.

[0065] Although the invention has been described herein with reference to specific embodiments, these embodiments are not intended to limit the invention and are described for illustrative purposes. Those skilled in the art will understand that modifications and improvements can be made without departing from the spirit and scope of the invention.

[0066] Such simple modifications and improvements to the embodiments disclosed herein are within the scope of the disclosed technology, and will be further defined by the appended claims to the patent application.

[0067] As will be understood from the foregoing, any feature of any embodiment may be combined with any other feature of any other embodiment or replaced with any other feature of any other embodiment.

[0068] Unless the context clearly requires otherwise, throughout the description and scope of the invention application, the terms "comprise," "include," and similar terms shall be interpreted as inclusive rather than exclusive or exhaustive; that is, in the sense of "including but not limited to." As used generally herein, the term "coupled" refers to two or more elements that can be directly connected or connected by one or more intermediate elements. Similarly, as used generally herein, the term "connected" refers to two or more elements that can be directly connected or connected by one or more intermediate elements. Furthermore, the terms "in this document," "above," "below," and similar terms, when used in this application, shall refer to the entire application and not any particular part thereof. Where the context permits, the use of singular or plural terms in the above [implementation] may also include either the plural or the singular, respectively. The word "or" in the context of a list of two or more items covers all of the following interpretations: any one of the items in the list, all the items in the list, and any combination of the items in the list.

[0069] Furthermore, unless explicitly stated otherwise, or otherwise understood within the context of the content used, the conditional language used herein (especially terms such as "can / could," "may," "may," "e.g. / for example," "like," and the like) is generally intended to convey that a particular embodiment includes a particular feature, element, and / or state that is not included in other embodiments. Therefore, this conditional language is generally not intended to imply that one or more embodiments require a feature, element, and / or state in any way, or whether such a feature, element, and / or state is included or should be performed in any particular embodiment.

[0070] While specific embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. In fact, the novel devices, methods, and systems described herein can be embodied in various other forms; furthermore, various omissions, substitutions, and changes in form of the methods and systems described herein can be made without departing from the spirit of the invention. For example, while features are presented according to a given configuration, alternative embodiments may utilize different components and / or sensor topologies to perform similar functionality, and some features may be deleted, moved, added, subdivided, combined, and / or modified. Various features can be implemented in various ways. Any suitable combination of elements and actions of the embodiments described above can be combined to provide further embodiments. The various features and procedures described above can be implemented independently of each other or can be combined in various ways. All possible combinations and sub-combinations of the features of the invention are intended to fall within the scope of the invention.

[0071] 100: Thin Film Deposition System 104: Thin Film Deposition Chamber 108: Liquid Precursor Panel / Liquid Panel 110: Liquid precursor material source unit 110-1 to 110-n: Liquid precursor source units 110a: Liquid tank 110a-1 to 110a-n: Liquid tanks 110b: Propeller gas pipeline 110b-1 to 110b-n: Propeller gas lines 110c: Liquid delivery line 110c-1 to 110c-n: Liquid delivery lines 110d-1 to 110d-n: Liquid Flow Meters (LFM) 111: Chamber outer shell 112: Liquid precursor delivery unit / Liquid precursor injection unit / Liquid injection unit / Liquid injection 113: Sprayer head 114: Carrier gas pipeline 114a: Mass Flow Controller 115: Heater 116: Gas Panel 117:Substrate 118: Liquid precursor inlet line / Liquid precursor inlet 120: Gas precursor inlet line / Gas precursor inlet 120a: Mass Flow Controller 124: Support 124S: Top surface 128: Exports 132: Mass Flow Meter 200: Liquid precursor injection system 204: Liquid Injection Unit / Liquid Precursor Injection Unit 208: Carrier Gas Valve 212: Mixed Region 216: Vaporization Chamber 220: Carrier Gas Heater 224: Pressure Regulator 228: Liquid precursors 302: Entrance 304: Metering valve 308: Leverage 312: Rod 316: Sealed ball 318: Ceramic valve seat 320: Export 400: Method 410: Provide 420: Operation 424: Set or lower 426: Set or add 428: Set or add 500: Liquid Precursor Delivery Stability Control System / Liquid Precursor Delivery Control System 510: Liquid-driven pressure control system 514: Liquid pressure sensing component 518: Liquid pressure control component 520: Injection Unit Temperature Control System 524: Liquid temperature sensing component 528: Liquid temperature control component 530: Carrier Gas Temperature Control System 534: Carrier gas temperature sensing component 538: Carrier gas temperature control component 540: Downstream pressure control system 544: Gas pressure sensing component 548: Gas pressure control component 550: Central Control Unit / Processing Unit 610: First Precursor 620: Second Precursor D: Axis of rotation PPG: Gas Pressure P PL: Liquid pressure TCG: Temperature TPL: Temperature

Claims

1. A method for delivering a liquid precursor into a thin film deposition chamber using a liquid precursor delivery unit, the method comprising: A liquid precursor is atomized into atomized precursor droplets using a liquid injection unit, and these atomized precursor droplets are vaporized into a vaporized liquid precursor in a vaporization chamber. The vaporized liquid precursor is then delivered to the thin film deposition chamber. The liquid injection unit and the liquid precursor cause the liquid precursor delivery unit to operate under relatively stable conditions, including a first liquid precursor temperature at the liquid injection unit, a first liquid precursor pressure upstream of the liquid injection unit, and a first gas pressure downstream of the liquid injection unit, resulting in a mass flow rate of the liquid precursor relative to the average mass flow rate of the liquid precursor during a first duration. The variation exceeds 10%, wherein delivering the vaporized liquid precursor into the thin film deposition chamber includes operating the liquid precursor delivery unit under conditions of higher stability including one or more of the following: a second liquid precursor temperature at the liquid injection unit that is lower than the first liquid precursor temperature, a second liquid precursor pressure upstream of the liquid injection unit that is higher than the first liquid precursor pressure, and a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure, such that the mass flow rate of the liquid precursor varies by less than 10% relative to an average mass flow rate during a second duration having the same duration as the first duration.

2. The method of claim 1, wherein the higher stability condition includes the temperature of the second liquid precursor at the liquid injection unit, and wherein the second liquid precursor temperature is achieved at least in part by actively cooling the liquid precursor at the liquid injection unit.

3. The method of claim 2, wherein delivering the vaporized liquid precursor comprises: The atomizing precursor droplets and a carrier gas are mixed before the atomizing precursor droplets are vaporized.

4. The method of claim 3, wherein mixing includes mixing a heated carrier gas with a cooled atomized precursor droplet, wherein the heated carrier gas system is formed by heating the carrier gas, and the cooled atomized precursor droplet is formed by cooling the liquid precursor, such that mixing includes mixing the cooled atomized precursor droplet with the heated carrier gas.

5. The method of claim 4, wherein cooling the liquid precursor includes cooling the liquid precursor at least 5°C, and heating the carrier gas includes heating the carrier gas at least 5°C.

6. The method of claim 5, wherein a temperature of the mixture of the atomized precursor droplets formed by the liquid precursor at the second liquid precursor temperature and the heated carrier gas is substantially the same as a temperature of the mixture of the atomized precursor droplets formed by the liquid precursor at the first liquid precursor temperature before the carrier gas is heated.

7. The method of claim 1, wherein the higher stability condition includes a second liquid precursor pressure upstream of the liquid injection unit that is higher than the first liquid precursor pressure, and wherein the second liquid precursor pressure is achieved at least in part by setting a liquid driving pressure upstream of the liquid injection unit.

8. The method of claim 7, wherein setting the liquid pushing pressure upstream of the liquid injection unit includes: Adjust the liquid-driven gas at one of the liquid precursor source units where the liquid precursor is stored.

9. The method of claim 8, wherein adjusting the liquid-driven gas includes adjusting the liquid-driven pressure to exceed 14 absolute psi, and wherein one of the liquid-driven pressures prior to adjustment is below 14 absolute psi.

10. The method of claim 1, wherein the higher stability condition includes a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure, and wherein the second gas pressure is higher than one of the pressures in the thin film deposition chamber.

11. The method of claim 10, wherein the second gas pressure downstream of the liquid injection unit is achieved at least in part by restricting one of the conductions between the liquid injection unit and the thin film deposition chamber.

12. The method of claim 11, wherein the atomizing precursor droplets are introduced into a mixing region, wherein the atomizing precursor droplets are vaporized in a vaporization chamber, and wherein limiting the conduction includes: The mixing region and one or both of the vaporization chamber are extended in a length direction relative to a width direction to have an aspect ratio of more than 1:

1.

13. The method of claim 11, wherein limiting the conduction includes adjusting a valve or a regulator.

14. The method of claim 11, wherein the second gas pressure is at least 10% greater than the first gas pressure.

15. The method of claim 1, wherein the liquid precursor has a difference of less than 100°C between a vaporization temperature and a decomposition temperature at atmospheric pressure.

16. The method of request item 1, wherein the duration of the first and second times exceeds 10 seconds.

17. The method of claim 1, wherein delivering the vaporized liquid precursor comprises: One of the pulses of the vaporized liquid precursor is delivered to deposit a thin film by a cyclic deposition process.

18. The method of claim 1, wherein delivering the liquid precursor comprises: The liquid precursor is continuously delivered to deposit a thin film via a continuous deposition process.

19. A method for delivering a liquid precursor into a thin film deposition chamber, the method comprising: A liquid precursor delivery unit is provided, configured to atomize a liquid precursor into atomized precursor droplets using a liquid injection unit, vaporize the atomized precursor droplets into a vaporized liquid precursor in a vaporization chamber, and deliver the vaporized liquid precursor to a thin film deposition chamber; deliver the vaporized liquid precursor to the thin film deposition chamber under relatively low stability conditions, the relatively low stability conditions including a first liquid precursor temperature at the liquid injection unit, a first liquid precursor pressure upstream of the liquid injection unit, and a first gas pressure downstream of the liquid injection unit; detect a large average mass flow rate relative to the liquid precursor during a first duration. A variation of 10% in the mass flow rate of the liquid precursor; delivery of the vaporized liquid precursor into the thin film deposition chamber under higher stability conditions, the higher stability conditions including one or more of the following: a second liquid precursor temperature at the liquid injection unit that is lower than the first liquid precursor temperature, a second liquid precursor pressure upstream of the liquid injection unit that is higher than the first liquid precursor pressure, and a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure, such that the mass flow rate of the liquid precursor changes by less than 10% relative to an average mass flow rate during a second duration having the same duration as the first duration.

20. The method of claim 19, wherein the higher stability condition includes the temperature of the second liquid precursor at the liquid injection unit, and wherein the second liquid precursor temperature is achieved at least in part by actively cooling the liquid precursor at the liquid injection unit by at least 5°C.

21. The method of claim 20, wherein delivering the vaporized liquid precursor comprises: The atomizing precursor droplets and a heated carrier gas are mixed before the atomizing precursor droplets are vaporized.

22. The method of claim 21, wherein a temperature of the mixture of the atomized precursor droplets formed by the liquid precursor at the second liquid precursor temperature and the heated carrier gas is substantially the same as a temperature of the mixture of the atomized precursor droplets formed by the liquid precursor at the first liquid precursor temperature before the carrier gas is heated to form the heated carrier gas.

23. The method of claim 19, wherein the higher stability condition includes the second liquid precursor pressure, and wherein the second liquid precursor pressure is achieved at least in part by setting a liquid driving pressure upstream of the liquid injection unit storing the liquid precursor.

24. The method of claim 23, wherein the liquid actuation pressure is set to exceed 14 absolute psi, and wherein, under one of the lower stability conditions, the liquid actuation pressure is below 14 absolute psi.

25. The method of claim 19, wherein the higher stability condition includes the second gas pressure, and wherein the second gas pressure of the liquid injection unit is higher than one of the pressures in the thin film deposition chamber.

26. The method of claim 25, wherein the second gas pressure downstream of the liquid injection unit is achieved at least in part by restricting one of the conductions between the liquid injection unit and the thin film deposition chamber, such that the second gas pressure is at least 10% greater than the first gas pressure.

27. The method of claim 19, wherein delivering the vaporized liquid precursor comprises: One of the liquid precursors is delivered in a pulse to deposit a thin film via a cyclic deposition process.

28. The method of claim 19, wherein delivering the vaporized liquid precursor comprises: The liquid precursor is continuously delivered to deposit a thin film via a continuous deposition process.

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