Liquid precursor implantation for thin film deposition

Abstract

The disclosed technology relates generally to semiconductor processing, and more particularly to a liquid precursor injection apparatus and a thin film deposition method. A method for injecting a liquid precursor into a thin film deposition chamber includes delivering a vaporized liquid precursor to the thin film deposition chamber by atomizing the liquid precursor into atomized precursor droplets using a liquid injection unit and vaporizing the atomized precursor droplets into a vaporized liquid precursor in a vaporization chamber. The liquid injection unit and the liquid precursor are configured such that the mass flow rate of the liquid precursor varies by 10% or more relative to the average mass flow rate of the liquid precursor during a first duration by operating the liquid precursor delivery unit under low 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. Delivering the vaporized liquid precursor to the thin film deposition chamber includes operating the liquid precursor delivery unit under high stability conditions. The high stability includes one or more of: a second liquid precursor temperature lower than the first liquid temperature at the liquid injection unit; a second liquid pressure higher than the first liquid pressure upstream of the injection unit; and a second gas pressure higher than the first gas pressure downstream of the liquid injection unit. The high stability is such that the mass flow rate of the liquid precursor varies by less than 10% relative to the average mass flow rate during a second duration having the same duration as the first duration.

Description

[Technical Field]

[0001] The disclosed technologies generally relate to semiconductor processing, and more particularly to liquid precursor injection apparatus and methods for depositing thin films. [Background technology]

[0002] As semiconductor devices are being scaled down laterally, this also includes scaling down their dimensions vertically, such as reducing the thickness of functional thin films like electrodes and dielectrics. Semiconductor manufacturing involves depositing a variety of thin films throughout the entire process flow. These diverse thin films are deposited using a variety of techniques, including wet and dry deposition methods. Wet deposition methods include, for example, aerosol / spray deposition, sol-gel deposition, and spin coating. Dry deposition methods include, for example, physical vapor-based techniques such as physical vapor deposition (PVD) and evaporation. Dry deposition methods further include precursor and / or chemical reaction-based techniques such as chemical vapor deposition (CVD) and atomic layer deposition (ALD). [Overview of the project] [Means for solving the problem]

[0003] In the first embodiment, the process includes atomizing a liquid precursor into atomized precursor droplets using a liquid injection unit and vaporizing the atomized precursor droplets into a vaporized liquid precursor in a vaporization chamber, thereby delivering the vaporized liquid precursor into a thin film deposition chamber. The liquid injection unit and liquid precursor are configured such that the mass flow rate of the liquid precursor fluctuates by more than 10% of the average mass flow rate of the liquid precursor during a first duration, by operating the liquid precursor delivery unit under lower stability conditions, including a first liquid precursor temperature in 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. Delivering a vaporized liquid precursor into a thin film deposition chamber involves operating the liquid precursor delivery unit under higher stability conditions. Higher stability includes one or more of the following: a second liquid precursor temperature higher than the first liquid precursor temperature in the liquid injection unit; a second liquid pressure upstream of the injection unit higher than the first liquid pressure; and a second gas pressure downstream of the liquid injection unit higher than the first gas pressure. Higher stability is such that the mass flow rate of the liquid precursor fluctuates by less than 10% of the 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 a liquid precursor delivery unit configured to deliver a vaporized liquid precursor into a thin film deposition chamber by atomizing the liquid precursor into atomized precursor droplets using a liquid injection unit, and then vaporizing the atomized precursor droplets into a vaporized liquid precursor in a vaporization 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 in 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. The method further includes detecting fluctuations in the mass flow rate of the liquid precursor that exceed 10% of the average mass flow rate of the liquid precursor during a first duration. The method further includes delivering a vaporized liquid precursor into a thin-film deposition chamber under higher stability conditions. The higher stability conditions include one or more of the following: a second liquid precursor temperature in the liquid injection unit lower than the first liquid precursor temperature; a second liquid precursor pressure upstream of the injection unit higher than the first liquid precursor pressure; and a second gas pressure downstream of the liquid injection unit higher than the first gas pressure. The higher stability conditions are such that the mass flow rate of the liquid precursor fluctuates by less than 10% of the average mass flow rate during a second duration having the same duration as the first duration.

[0005] In a third embodiment, the apparatus for delivering a liquid precursor into a thin film deposition chamber includes a liquid precursor delivery system configured for delivering a vaporized liquid precursor into the thin film deposition chamber. The liquid precursor delivery system includes a liquid injection unit configured for atomizing the liquid precursor into atomized precursor droplets, a mixing area configured to receive the atomized precursor droplets from the liquid injection unit and generate a mixture of the atomized precursor droplets and a transport gas, and a vaporization chamber configured to receive the mixture and vaporize the atomized precursor droplets in the mixture to generate a vaporized liquid precursor. The apparatus further includes a liquid precursor delivery stability control system comprising one or more of the following: an injection unit temperature control system configured to detect and control the liquid precursor temperature in the liquid injection unit before it is introduced into the mixing area; a transport gas temperature control system configured to detect and control the transport gas temperature before it is introduced into the mixing area; a liquid push pressure control system configured to detect and control the liquid precursor pressure upstream of the liquid injection unit; and a downstream gas pressure control system configured to detect and control the gas pressure downstream of the liquid injection unit. [Brief explanation of the drawing]

[0006] [Figure 1A] Figure 1A shows a thin-film deposition system configured to deliver a vaporized liquid precursor into a thin-film deposition chamber according to an embodiment. [Figure 1B] Figure 1B shows the thin film deposition chamber of the thin film deposition system shown in Figure 1A, according to an embodiment. [Figure 2] Figure 2 shows a liquid precursor delivery unit for delivering a vaporized liquid precursor into a thin film deposition chamber, according to an embodiment. [Figure 3A] Figure 3A shows an example of a liquid injection unit configured to atomize a liquid precursor into atomization precursor droplets according to an embodiment. [Figure 3B] Figure 3B shows an example of a liquid injection unit configured to atomize a liquid precursor into atomization precursor droplets according to an embodiment. [Figure 4]FIG. 4 shows a method for delivering a liquid precursor into a thin film deposition chamber according to an embodiment. [Figure 5] FIG. 5 shows a liquid precursor delivery stabilization control system for controlling the delivery of a vaporized liquid precursor into a thin film deposition chamber according to an embodiment. [Figure 6A] FIG. 6A shows a thin film deposition process capable of executing a liquid precursor delivery method and system according to an example. [Figure 6B] FIG. 6B shows a thin film deposition process capable of executing a liquid precursor delivery method and system according to an example. [Figure 6C] FIG. 6C shows a thin film deposition process capable of executing a liquid precursor delivery method and system according to an example. [Figure 7] FIG. 7 shows a graph of an experiment of mass flow rate as a function of time for a liquid precursor introduced into a thin film deposition chamber in pulse mode using a liquid precursor delivery method according to an example.

DETAILED DESCRIPTION OF THE INVENTION

[0007] Cyclic deposition processes such as atomic layer deposition (ALD) processes can provide highly uniform and relatively conformal conductive and insulating thin films on structures with a relatively high aspect ratio (e.g., 2:1). Although the conformality and uniformity are generally inferior to those of ALD, thin films deposited using continuous deposition processes such as chemical vapor deposition (CVD) can achieve higher productivity and lower costs. ALD and CVD can be used to deposit a wide variety of different thin films, such as elemental metals, semiconductors (e.g., Si, III-V, etc.), dielectrics (e.g., SiO2, AlN, HfO2, ZrO2, etc.), rare earth oxides, conductive oxides and oxynitrides (e.g., TiN, IrO2, etc.), ferroelectrics (e.g., PbTiO3, LaNiO3, etc.), superconductors (e.g., YBa2Cu3O 7-x )), chalcogenides (e.g., GeSbTe), and so on, without end.

[0008] In precursor- or chemical reaction-based thin film deposition technologies such as CVD and ALD processes, the precursor is delivered into a reactor and transported to a substrate that can be heated within it to deposit a thin film. Gaseous precursors with high vapor pressure (e.g., >0.1 Torr) are relatively easy to control, but not all precursors exist in gaseous form at atmospheric pressure and room temperature. Many precursors are available in liquid form. Compared to the delivery of gaseous precursors, precisely controlling the delivery of liquid precursors into the reactor chamber is relatively difficult, which makes it more challenging to control the composition, nanostructure, and consistency of thin films obtained using liquid precursors. Therefore, there is a need to improve the delivery of liquid precursors into the reactor chamber in order to improve the control of the deposition properties of the resulting thin films, such as growth rate, in-substrate uniformity, inter-substrate uniformity, surface morphology, and film density.

[0009] Bubbler technology can be used in several common precursor or chemical reaction-based thin-film deposition techniques that utilize liquid precursors. In bubbler technology, the liquid precursor is stored inside a bubbler, typically a stainless steel canister, and an inert carrier gas (Ar, He, N2, etc.) is introduced into the liquid to create bubbles. The precursor vapor saturates the air inside the bubbler, and the resulting vapor is introduced onto the substrate surface. The delivery of reactants in these techniques depends on parameters including the bubbler temperature, the flow rate of the carrier gas, and the pressure on the liquid surface. While bubbler-based techniques can work well for some liquid precursors, they may not be suitable for precursors with relatively low vapor pressures. This is because heating the bubbler can be a practical way to increase the vapor pressure inside the canister, but the maximum temperature at which the bubbler can be heated may be limited to the decomposition temperature of the precursor. However, many liquid precursors have relatively low decomposition temperatures. Therefore, bubbler-based techniques may not be practical for precursors where the 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 is relatively narrow, such as approximately 150°C, 100°C, or less than 50°C. As a result, bubbler-based techniques may be limited to those employing precursors that are stable at relatively high temperatures.

[0010] To overcome the limitations of bubbler-based liquid precursor delivery methods, the systems and methods described herein employ direct liquid injection technology. As used herein, the term direct liquid injection (DLI) refers to a technique that uses a liquid precursor delivery unit, such as an injector, to supply reactants to a deposition region. Unlike other techniques, such as bubbler technology, DLI-based techniques keep the liquid precursor in liquid form until the point of injection into a low-pressure deposition chamber under vacuum. DLI-based techniques allow for precise control of the liquid mass flow rate, even with precursors that have 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. According to some embodiments disclosed herein, the temperature window of the liquid precursor used in the liquid precursor delivery methods and systems may be 150°C, 100°C, 50°C, less than 25°C, or a temperature window between any of these values.

[0011] In some DLI-based technologies, the liquid precursor passes through a vaporization chamber where it is vaporized, and in other cases, the precursor reaches the heated substrate surface in a liquid state, for example, in the form of atomized liquid precursor droplets, which are then vaporized before decomposition. When the precursor is still in the liquid phase when it reaches the substrate, the deposition method may be called spray decomposition or aerosol decomposition, depending on how the liquid droplets are formed. Some spray / aerosol decomposition processes are sometimes called atmospheric pressure CVD because evaporation usually takes place near a substrate heated to a high temperature. An advantage of DLI-based technologies is that the liquid precursor is relatively low in temperature, e.g., room temperature, which allows the use of precursors with low temperature stability and low vapor pressure.

[0012] The inventors recognized that in some general-purpose liquid delivery systems and methods, the mass flow rate of the liquid precursor can be unstable. While not bound by any theory, the inventors found that one cause of mass flow rate instability may, in particular, be related to unintended or excessive vaporization of the liquid precursor in or near a general-purpose valve or injector, upstream of the injection point, before it is injected into a low-pressure region, such as a vaporization chamber. When delivered by a general-purpose valve or injector, the liquid precursor is intended to remain in the liquid phase until the injection point. However, the inventors found that a considerable amount of unintended vaporization of the liquid precursor can occur upstream of the injection point. This unintended vaporization can occur upstream of the injection point, for one reason being that the liquid precursor may be heated to near its vaporization temperature at the injection point, and / or that the gas pressure downstream of the valve or injector may be considerably lower than the vapor pressure during deposition. As a result, unintended vaporization of the liquid precursor may occur to a considerable extent upstream of the injection point. This vaporization of the liquid precursor upstream of the injection point can induce gas or bubble pockets, which in turn can lead to instability in the mass flow rate of the liquid precursor for depositing thin films in the thin film deposition chamber. To address these and other requirements, the systems and methods disclosed herein enable the delivery of liquid precursor into the thin film deposition chamber with improved liquid precursor stability and mass flow rate reproducibility.

[0013] [Thin film deposition system configured for liquid precursor injection] Figure 1A shows a thin-film deposition system configured to deliver vaporized liquid precursors into a thin-film deposition chamber. 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. Their flow through the carrier gas line 114 is controlled by a mass flow controller 114a. The liquid precursor delivery unit 112 is configured to deliver one or more vaporized liquid precursors into the 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 further configured to receive one or more gas precursors, such as an oxidizing agent such as O2 or NH3. Their flow from the gas panel 116 through one or more gas precursor inlet lines 120 is controlled by a mass flow controller 120a.

[0014] The liquid panel 108 includes one or more liquid precursor source units 110-1, 110-2, ..., 110-n, each having a liquid tank 110a-1, 110a-2, ..., 110a-n configured to hold individual liquid precursors. The liquid tanks 110a-1, 110a-2, ..., 110a-n are connected to push gas lines 110b-1, 110b-2, ..., 110b-n, and to liquid delivery lines 110c-1, 110c-2, ..., 110c-n. Liquid flow meters (LFMs) 110d-1, 110d-2, ..., 110d-n are positioned in the flow paths of liquid delivery lines 110c-1, 110c-2, ..., 110c-n between liquid tanks 110a-1, 110a-2, ..., 110a-n and liquid precursor delivery unit 112.

[0015] In the illustrated embodiment, multiple liquid precursors are shown to be introduced into a common liquid precursor delivery unit 112. However, the configuration is not limited to this one, and in other configurations, there may be multiple liquid precursor delivery units 112, in which case each liquid precursor delivery unit 112 is dedicated to an individual liquid precursor. Furthermore, a single transport gas line 114 is shown to be connected to the liquid precursor delivery unit 112. However, the configuration is not limited to this one, and there may be multiple transport gas lines 114, in which case each transport gas line is connected to a dedicated liquid precursor delivery unit 112, so that each liquid precursor delivery unit 112 receives its own dedicated liquid precursor and dedicated transport gas (e.g., Figure 2).

[0016] Liquid precursor source units 110-1, 110-2, ..., 110-n can be operated qualitatively in a similar manner. Referring to liquid precursor source unit 101-1 as an example, a push gas, which is an inert gas such as hydrogen, helium, argon, or nitrogen, flows out of the push gas line 110b-1 and through a gas mass flow controller (not shown) into the liquid tank 110a-1. The push 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.

[0017] Figure 1B shows a thin film deposition chamber of a thin film deposition system according to an embodiment, which is, for example, 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.

[0018] The lower part of the thin film deposition chamber 104 includes a susceptor 124 having an upper surface 124S configured for a substrate 117 placed on top thereof. The susceptor 124 can be heated to process temperature by a heating device 115. In a given configuration, the susceptor 124 may rotate about a rotation axis D to improve film uniformity. The rotation may occur relative to the central axis. A vacuum pump (not shown), connected to the thin film deposition chamber 104 via an outlet 128, is configured to evacuate the inside of the thin film deposition chamber 104. The upper part of the thin film deposition chamber 104 includes a gas distribution plate, or showerhead 113, having a plurality of holes for releasing a passing gas mixture onto the substrate 117.

[0019] One or more liquid precursor inlet lines 118 configured to deliver vaporized liquid precursors from a liquid precursor delivery unit 112, and one or more gas precursor inlet lines 120 configured to deliver individual gas precursors, such as oxidizers, from a gas panel 116, are connected to a showerhead 113. One or more mass flow meters 132 can be placed in the flow paths of the liquid precursor inlet lines 118 and gas precursor inlet lines 120 to measure the mass flow rates of the vaporized liquid precursors and gas precursors. According to various embodiments disclosed herein, fluctuations in the mass flow rate of the vaporized liquid precursor(s) can be detected by a liquid precursor delivery stability control system 500 (Figure 5) to operate the liquid precursor delivery method under higher stability conditions. For example, when the detected mass flow rate of the vaporized liquid precursor(s) fluctuates by more than 10% of the average mass flow rate of the liquid precursor during a first duration, exceeding a manufacturing tolerance, the liquid precursor delivery stability control system 500 can trigger method 400 (Figure 4) according to an embodiment.

[0020] • Liquid precursor delivery system Figure 2 shows an embodiment of a liquid precursor injection system for delivering a vaporized liquid precursor into a thin film deposition chamber, which is, for example, 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 the liquid precursor in liquid phase from a liquid precursor source unit 110. The liquid precursor source unit 110 includes a liquid tank 110a in which the liquid precursor 228 is stored. A push gas line 110b is connected to the liquid tank 110a through a pressure regulator 224. A liquid delivery line 110c is connected to the liquid injection unit 204 configured to atomize the liquid precursor 228. As disclosed herein, atomization is the process of forming the liquid precursor into a spray of liquid precursor droplets. The atomized liquid droplets may have an average diameter of, for example, about 1 μm to 100 μm. The droplets have a large surface area-to-volume ratio and are optimized for rapid evaporation into the vaporized liquid precursor.

[0021] During operation, in order to deliver the liquid precursor 228 released from the liquid tank 110a, a push gas, which is an inert gas such as hydrogen, helium, argon, or nitrogen, is supplied to the liquid tank 110a through the push gas line 110b, thereby moving the liquid precursor 228 from the liquid tank 110a. The gas flow through the push gas line 110b can be adjusted by the pressure regulator 224. The liquid precursor thus moved is delivered to the liquid injection unit 204 through the liquid delivery line 110c.

[0022] The liquid precursor delivery unit 112 further includes a transport gas valve 208 configured to receive a transport gas through a transport gas line 114. This can be hydrogen or an inert gas such as helium, argon, or nitrogen. A transport gas heater 220 can be placed along the transport gas line 114 to adjust the temperature of the transport gas delivered to the transport gas valve 208. The liquid precursor delivery unit 112 further includes a mixing area 212 downstream of the liquid injection unit 204 and the transport gas valve 208, configured to mix atomized liquid precursor droplets and the transport gas to form an atomized liquid precursor mixture. The liquid injection unit 204 and the transport gas valve 208 are configured to eject atomized precursor droplets and the transport gas into the mixing area 212, respectively. In the given configuration, the trajectories of the atomization precursor droplets ejected from the liquid injection unit 204 and the trajectories of the transport gas ejected from the transport gas valve 208 can intersect at the mixing point in the mixing area 212, thereby ensuring that an atomization liquid precursor mixture is sufficiently formed by mixing the atomization precursor droplets and the transport gas before vaporization.

[0023] The atomizing liquid precursor mixture formed in the mixing area 212 from atomizing precursor droplets and a carrier gas is subsequently introduced into the vaporization chamber 216. The vaporization chamber 216 is configured to vaporize the atomizing precursor droplets in the atomizing liquid precursor mixture to form a vaporizing liquid precursor mixture containing the vaporizing liquid precursor and the carrier gas. The vaporization chamber 216 may have a volume of about 1 to 3 liters. The vaporization chamber 216 has vaporization means, such as a heating device. For example, vaporization of the atomizing precursor droplets can be achieved in part by the heated walls of the vaporization chamber 216. The walls of the vaporization chamber 216 can be heated to a temperature such that the atomizing 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 with 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 the showerhead 113, as described above with respect to Figures 1A and 1B. As described above with respect to Figures 1A and 1B, one or more gas precursors, such as an oxidizer from the gas panel 116, are delivered through the gas precursor inlet 120, which is also connected to the showerhead 113.

[0024] Referring further to Figure 2, the mixing area 212 and the vaporization chamber 216 are connected to a thin film deposition chamber 104, which may be under vacuum or thin film deposition chamber pressure, but can be configured to have a local pressure higher than the deposition chamber pressure. Higher local pressures can be achieved by designing the shape of the internal spaces of the mixing area 212 and / or the vaporization chamber 216 to limit their conductance. For example, one or both of the mixing area 212 and / or the vaporization chamber 216 may include an elongated portion extending vertically perpendicular to the surface of the showerhead 113, thereby creating a vertical pressure gradient. For example, one or both of the mixing area 212 and / or the vaporization chamber 216 may have an aspect ratio greater than 2:1, 4:1, 6:1, 8:1, 10:1 or any of these values ​​as the aspect ratio of the vertical length to the horizontal width or diameter. Alternatively, the mixing area 212 and / or the vaporization chamber 216 may be partially obstructed from exhaust by, for example, a conductance limiting orifice. Alternatively, one or both of the mixing area 212 and / or the vaporization chamber 216 may include a continuously adjustable conductance control means at its lower part, such as a pressure regulator or butterfly valve, so that the local pressure at that point is higher than the deposition chamber pressure. For example, the conductance control means may be located between the mixing area 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 showerhead 113.

[0025] In the illustrated embodiment, the mixing area 212 and the vaporization chamber 216 are shown as separate chambers. However, the configuration is not limited to this, and in other configurations, the mixing area 212 may form part of the vaporization chamber 216, while having an internal space of a different shape and size than the elongated space described above. In other given configurations, the mixing area 212 can be omitted, and the atomizing liquid precursor and the transport gas can be directly introduced into the vaporization chamber 216.

[0026] Referring further to Figure 2, the liquid injection unit 204 may include appropriate means configured to atomize the liquid precursor into atomization precursor droplets, i.e., aerosols. In one embodiment, the liquid injection unit 204 may include a metering valve. Figures 3A and 3B show an example of the liquid injection unit 204 according to an embodiment, including a metering valve 304 configured to atomize the liquid precursor into atomization precursor droplets. The metering valve 304 in the illustrated example is similar to the PICO® valve manufactured by Nordson EFD LLC, whose specifications and design are incorporated herein by reference in their entirety. Figure 3A shows the metering valve 304 in a closed position, and Figure 3B shows the metering valve 304 in an open position. The metering valve 304 includes an inlet 302 connected to a liquid delivery line 110c to receive the liquid precursor 228 from the liquid precursor source unit 110 (Figure 2), and an outlet 320 connected to a mixing area 212 (Figure 2). The metering valve 304 includes a lever 308 configured to be driven by a piezoelectric actuator to move up and down as indicated by the arrows. The lever 308 has a distal end to which a vertical rod 312 is movably connected. The movement of the lever 308 results in the corresponding vertical movement of the rod 312 as indicated by the arrows. A hemispherical sealing ball 316 made of wear-resistant ceramic is positioned at the lower end of the rod 312. A ceramic valve seat 318, also referred to as a nozzle plate, is positioned below the sealing ball 316. The ceramic valve seat 318 has a hole smaller than the diameter of the sealing ball 316. The hole may have a diameter of, for example, 50 μm to 500 μm. In the illustrated example of the metering valve 304, the hole in the valve seat 318 can represent the injection point. As described herein, the injection point defines a region within the liquid injection unit 204 to which the liquid precursor 228 is atomized into atomization precursor droplets. The injection point also defines the point that separates the upstream portion of the metering valve 304, where the liquid precursor is in a liquid state, from the downstream portion of the metering valve 304, which is exposed to a low-pressure region, such as the mixing area 212.

[0027] As shown in Figure 3A, during operation, when the sealing ball 316 seats on the valve seat 318, the sealing ball 316 closes the hole or injection point, thereby preventing the injection of the liquid precursor 228 from the metering valve 304. On the other hand, as shown in Figure 3B, when the sealing ball 316 rises away from the valve seat 318, the sealing ball 316 opens the hole or injection point, thereby allowing the liquid precursor 228 to be injected or sprayed from the metering valve 304.

[0028] Other embodiments of the liquid injection unit 204 (Figure 2) are possible. According to an alternative embodiment, the injection unit 204 (Figure 2) may include a mass flow controller including a control valve, which can change the liquid flow rate by changing the position of the valve. According to yet another alternative embodiment, the injection unit 204 may include a mass flow meter without a control valve, which can change the liquid flow rate by changing the driving pressure applied thereto.

[0029] • Liquid injection method and control system Figure 4 shows a method for delivering a liquid precursor into a thin-film deposition chamber according to an embodiment. Figure 5 shows a liquid precursor delivery stability control system for controlling the delivery of a vaporized liquid precursor into a thin-film deposition chamber according to an embodiment. The liquid precursor delivery method 400 (Figure 4) will be described below in relation to the control system 500 (Figure 5).

[0030] Referring to Figure 5, the liquid precursor delivery control system 500 for controlling the delivery of the vaporized liquid precursor into the thin film deposition chamber includes a liquid push pressure control system 510, an injection unit temperature control system 520, a transport gas temperature control system 530, and a downstream pressure control system 540, which are communicated with each other and with a central control unit 550. The liquid push pressure control system 510, which can be positioned upstream of the liquid injection unit 204 (Figure 2), is configured to control the liquid precursor push pressure in the liquid delivery line 110c (Figure 2) upstream of the liquid precursor delivery unit 112 (Figure 2) using a liquid pressure detection means 514 and a liquid pressure control means 518 that are communicated with each other. The liquid injection unit 204 (Figure 2) or the injection unit temperature control system 520, which can be positioned upstream thereof, is configured to control the liquid precursor temperature in or above the liquid injection unit 204 (Figure 2) using a liquid temperature detection means 524 and a liquid temperature control means 528 that are communicated with each other. The conveying gas temperature control system 530, which can be positioned upstream of the conveying gas valve 208 (Figure 2), is configured to control the conveying gas temperature above the conveying gas valve 208 (Figure 2) using a conveying gas temperature detection means 534 and a conveying gas temperature control means 538 that are communicated with each other. The downstream pressure control system 540, which can be positioned downstream of the liquid injection unit 204 (Figure 2), is configured to control the gas pressure downstream of the liquid injection unit 204 (Figure 2) using a gas pressure detection means 544 and a gas pressure control means 548 that are communicated with each other. Each of the liquid pressure detection means 514 and the gas pressure detection means 544 may include a suitable pressure sensor such as a nanometer or transducer. Each of the liquid temperature detection means 214 and the transport gas temperature detection means 534 may include a suitable temperature sensor such as a thermocouple, thermistor, or resistance temperature detector. Each of the liquid pressure control means 518 and the gas pressure control means 548 may include a pressure regulator, control valve, etc., which can be controlled by a suitable control circuit and / or control algorithm. Each of the liquid temperature control means 528 and the transport gas temperature control means 538 may include a heating device and / or cooling device, which can be controlled by an internal or external control circuit and / or control algorithm.

[0031] Referring further to Figure 5, each of the liquid push pressure control system 510, the injection unit temperature control system 520, the transport gas temperature control system 530, and the downstream pressure control system 540, as well as each detection means and control means included therein, are communicated with each other and with a central control or processing unit 550. The central control or processing unit 550 has a processor, memory, and storage devices, which are centrally configured to communicate with the liquid push pressure control system 510, the injection unit temperature control system 520, the transport gas temperature control system 530, and the downstream pressure control system 540, and to store and execute executable algorithms for at least partially automatically controlling them. This enables the automatic or algorithmic execution of part or all of method 400. For example, one or more of the liquid push pressure control system 510, the injection unit temperature control system 520, the transport gas temperature control system 530, and the downstream pressure control system 540 may be activated in response to the detection of a mass flow rate fluctuation outside a predetermined manufacturing tolerance range. Flow rate fluctuations may be detected, for example, by a mass flow meter 132 (Figure 1B). In response to the detection of mass flow rate fluctuations outside of manufacturing tolerances, one or more of the liquid pressure control means 518, liquid temperature control means 528, transport gas temperature control means 538, and gas pressure control means 548 can automatically or algorithmically adjust, at least partially in conjunction with the central control unit 550, the liquid push pressure in the liquid delivery line 110c (Figure 2), the liquid precursor temperature in or above the liquid injection unit 204 (Figure 2), the transport gas temperature in or above the transport gas valve 208 (Figure 2), and the gas pressure downstream of the liquid injection unit 204 (Figure 2), respectively.

[0032] Referring to Figures 4 and 5, the 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 has a liquid injection unit 204 (Figure 2) configured to atomize the liquid precursor into atomized precursor droplets before delivery into the thin film deposition chamber 104 (Figure 2). The method further includes delivering a vaporized liquid precursor into the thin film deposition chamber 104 using the liquid precursor delivery unit 112, and delivering the vaporized liquid precursor includes atomizing the liquid precursor 228 into vaporized precursor droplets using the liquid injection unit 204 and vaporizing the atomized precursor droplets into a vaporized liquid precursor using the vaporization chamber 216. The liquid precursor delivery unit 112 and the liquid precursor 228 are configured such that when the liquid precursor delivery unit 112 operates under lower stability conditions, the mass flow rate of the liquid precursor fluctuates beyond the manufacturing tolerance relative to the average mass flow rate of the liquid precursor 228 during a first duration.

[0033] The lower stability conditions that cause such fluctuations are the first liquid precursor temperature (T) in the liquid injection unit 204 (Figure 2). PL1 ) and the first liquid precursor pressure (P) upstream of the liquid injection unit 204. PL1 ) and the first gas pressure (P) downstream of the liquid injection unit 204 PG1 ) and the present inventors have found that such fluctuations in mass flow rate can result in manufacturing non-uniformity, including variations in film quality such as thickness, composition, and density, not only across a single substrate but also between different substrates.

[0034] The inventors have found that by operating the liquid precursor delivery unit 112 under higher stability conditions 420, the mass flow rate of the liquid precursor fluctuates within less than the manufacturing tolerance with respect to the average mass flow rate during a second duration having the same duration as the first duration. In a given embodiment, operating the liquid precursor delivery unit 112 under higher stability conditions 420: the temperature of the liquid precursor 228 is set to the first liquid precursor temperature (T PL1Set or lower to a second liquid precursor temperature (T3) in the liquid injection unit 204 (FIG. 2) that is lower than PL1 Set or raise to a second liquid precursor pressure (P PL2 ) that is higher than the first liquid precursor pressure (P PG1 ) upstream of the injection unit; and set or raise the gas pressure downstream of the liquid injection unit 204 to a second gas pressure (P PG2 ) that is higher than the first downstream pressure (P

[0035] Referring further to FIG. 4, the inventors have found that operating the liquid precursor delivery unit 112 (FIG. 2) under higher stability conditions in the various embodiments disclosed herein 420 enables the delivery of the liquid precursor 228 into the thin film deposition chamber 104 with enhanced stability and reproducibility. The enhanced stability and reproducibility are particularly enabled, at least in part, as described above, by keeping the liquid precursor in the liquid phase and preventing vaporization of the liquid precursor upstream of the injection point. Advantageously, the method 400 enables substantial suppression of vaporization of the liquid precursor upstream of the injection point, which in turn suppresses the formation of gas or bubble pockets, thereby enhancing the stability of the vaporized precursor for depositing a thin film in the thin film deposition chamber 104 (FIG. 2).

[0036] The enhanced stability and reproducibility of the mass flow rate of the liquid precursor can be favorably maintained despite the fact that 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 considerably lower than the vapor pressure during deposition. As described herein, the vaporization temperature is the temperature at which the vapor pressure of the liquid precursor is sufficient for deposition, for example, the temperature at which the vapor pressure is above a value defined by approximately 0.1 Torr, 0.2 Torr, 0.5 Torr, 1 Torr, or any of these values. The temperature of the liquid precursor 228 can be set near the vaporization temperature and / or decomposition temperature. According to various embodiments, the liquid precursor delivery unit 112 (Figure 2) or the liquid precursor 228 (Figure 2) at the injection point therein can be set to a value within the range defined by the vaporization temperature of the liquid precursor 228 as + / -50°C, + / -30°C, + / -20°C, + / -10°C, or any of these values, or it can be set to a value within the range defined by the decomposition temperature of the liquid precursor 228 as 50°C, 30°C, 20°C, 10°C, or any of these values. For example, the pressure downstream of the injection point in the mixing area 212 (Figure 2), vaporization chamber 216 (Figure 2), and / or thin film deposition chamber 104 (Figure 2) can be within the range of 0.01-0.2 Torr, 0.2-0.4 Torr, 0.4-0.6 Torr, 0.6-0.8 Torr, 0.8-1.0 Torr, 1.0-1.5 Torr, 1.5-2.0 Torr, 2.0-2.5 Torr, 2.5-3.0 Torr, 3.0-4.0 Torr, 4.0-5.0 Torr, 5.0-6.0 Torr, 6.0-7.0 Torr, 7.0-8.0 Torr, 8.0-9.0 Torr, 9.0-10.0 Torr, 10.0-11.0 Torr, 11.0-12.0 Torr, or any of these values.

[0037] Referring further to Figure 4, the enhanced stability and repeatability can be quantified by the variation in mass flow rate, which can be measured by the mass flow meter 132 (Figure 1B) against the manufacturing tolerance. An advantage is that by operating the liquid precursor delivery unit 112 under higher stability conditions 420, the mass flow rate of the liquid precursor can be maintained within the manufacturing tolerance. The manufacturing tolerance for the mass flow rate of the liquid precursor may depend on the application. For example, in dielectric and conductive thin films for the manufacture of memory and logic semiconductor chips at advanced technology nodes (e.g., <130nm), manufacturing tolerances can be defined as the mass flow rate not fluctuating by more than 1%, 2%, 5%, 10%, 20%, or any of these values ​​relative to the average mass flow rate of the liquid precursor during durations longer than those defined by 1ms, 5ms, 10ms, 20ms, 50ms, 100ms, 200ms, 500ms, 1000s, 2000s, 5000s, 10,000s, 100,000s, 1,000,000s, or any of these values. For example, the duration may correspond to the accumulated exposure time of hundreds or thousands of wafer processes between consecutive preventive maintenance operations of a thin film deposition system. In continuous precursor exposure such as chemical vapor deposition (CVD), the duration can represent the uninterrupted duration. In periodic precursor exposure such as atomic layer deposition (ALD), the duration can be the duration of a single pulse or the sum of multiple depositions. In a given embodiment, the duration can exclude transient effects such as an initial spike or dip when the liquid precursor delivery unit 112 (Figure 2) is first activated.

[0038] Referring further to Figure 4, in a given embodiment, operating the liquid precursor delivery unit 112 (Figure 2) under higher stability conditions is achieved by adjusting the temperature of the liquid precursor 228 (T PL ) under lower stability conditions, the first liquid precursor temperature (T PL1 The second liquid precursor temperature (T) in the liquid injection unit 204 is lower than ). PL2This includes setting or lowering 424. PL2 In part, the injection unit temperature control system 520 (Figure 5) is used, or the injection unit temperature control system 520 is used in combination with the transport gas temperature control system 530 (Figure 5), to control the T of the liquid injection unit 204 (Figure 2). PL2 This can be achieved by lowering the temperature of the liquid precursor 228 (Figure 2) to 424.

[0039] 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 sprayed into the mixing area 212, using liquid temperature sensing means 524 and liquid temperature control means 528. For example, if a mass flow rate outside of manufacturing tolerances is detected using the mass flow meter 132 (Figure 1B), the liquid temperature sensing means 534 and liquid temperature control means 528 can automatically or algorithmically adjust the temperature of the liquid precursor at or above the injection point in the liquid injection unit 204 (Figure 2), at least in conjunction with the central control unit 550.

[0040] The liquid temperature control means 528 controls the temperature (T) of the liquid precursor 228 in the injection unit 204 (Figure 2) before it is sprayed into the mixing area 212 (Figure 2). PL Active cooling means may be included to lower the temperature of the first and second liquid precursors (T) upstream of the injection point, for example, immediately upstream. PL1 , T PL2 One or both of the following can be set or lowered to a value within the range defined by + / -50°C, + / -30°C, + / -20°C, + / -10°C, or any of these values, of the vaporization temperature of the liquid precursor 228 at atmospheric pressure, or to a value within the range defined by 50°C, 30°C, 20°C, 10°C, or any of these values, of the decomposition temperature of the liquid precursor 228 (Figure 2) at atmospheric pressure. By actively cooling, the temperature of the liquid precursor is T P1 From T P2Up to a certain point, the temperature can be favorably set or lowered only to values ​​within the 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 values. As mentioned above, a temperature lower than these ranges can be favorably set or lowered. PL This leads to insufficient vaporization of the liquid precursor, and higher T than these ranges. PL This can lead to the decomposition of the liquid precursor, therefore within these ranges T PL It will become clear that controlling this is important.

[0041] The inventors have found that, under given circumstances, cooling the temperature of the liquid precursor as described herein can result in undesirable negative consequences. For example, lowering the liquid precursor temperature may reduce the atomization efficiency, i.e., the efficiency of precursor droplet formation, and / or the mixing efficiency in the mixing area 212, and / or the vaporization efficiency in the vaporization chamber 216. To eliminate these and other possible negative effects, in a given embodiment, the lowered second liquid precursor temperature (T) of the liquid precursor 228 is reduced. PL2 However, as will be described later, this is at least partially compensated by heating the transport gas and mixing the atomized precursor droplets formed from the cooled liquid precursor with the heated transport gas in the mixing area 212 (Figure 2).

[0042] Referring to Figure 5, the transport gas temperature control system 530 uses the transport gas temperature detection means 534 and the transport gas temperature control means 538 to control the temperature of the transport gas (T) before it is introduced into the mixing area 212. CG ) are configured to actively control the following. For example, in response to detecting fluctuations in mass flow rate outside of manufacturing tolerances using a mass flow meter 132 (Figure 1B), the transport gas temperature detection means 534 and the transport gas temperature control means 538 can be adjusted automatically or algorithmically, at least in conjunction with the central control unit 550, so that the transport gas temperature in the transport gas valve 208 above the mixing area 212 (Figure 2) is heated to a higher temperature and / or maintained therein.

[0043] In these embodiments, the transport gas valve 208 can be configured to actively control the temperature of the transport gas before it is delivered into the mixing area 212. For example, the transport gas temperature control system 530 may include an active heating means introduced into the transport gas valve 208. The transport gas temperature control system 520 may include, for example, a transport gas temperature sensing means 534 configured to detect the temperature of the transport gas upstream of the transport gas valve 208, and a transport gas temperature control means 538 including a heating device for actively raising the temperature of the transport gas before it is introduced into the mixing area 212. The temperature of the transport gas is a lower transport temperature (T) under lower stability conditions. CG1 From 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 a range defined by any of these values, the transport temperature (T CG2 It can be heated up to ).

[0044] One advantage is that the transport gas can be transported under lower stability conditions. CG1 From T under higher stability conditions CG2 By heating to this temperature, the cooling effect of the liquid precursor is at least partially compensated for when the liquid precursor is sprayed into the mixing area 212 (Figure 2). According to various embodiments, the second liquid precursor temperature (T PL2 ) A atomizing precursor droplet formed from a liquid precursor is T CG2 The temperature of the atomized liquid precursor mixture formed by mixing with the heated transport gas is lower than the first liquid precursor temperature (T) under lower stability conditions. PL1 ) The atomizing precursor droplets formed from the liquid precursor are heated to T CG1The temperature of the atomized liquid precursor mixture formed by mixing with the transport gas can be substantially the same as that of the mixture itself. For example, the temperature change of the atomized liquid precursor mixture in the mixing area 212 between lower and higher stability conditions can be within the range defined by 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 it is important to control the temperature of the atomized precursor mixture within these ranges, as low temperatures will result in insufficient vaporization of the liquid precursor, while high temperatures will lead to decomposition of the liquid precursor.

[0045] Referring further to Figure 4, in a given embodiment, operating the liquid precursor delivery unit 112 (Figure 2) under higher stability conditions is achieved by increasing the liquid pressure (P) of the liquid precursor 228. PL ) is the first liquid pressure (P) under lower stability conditions upstream of the injection point in the liquid injection unit 204. PL1 A second liquid pressure (P) higher than the second liquid pressure (P) of the injection point upstream of the injection point in the injection unit 204, which is a condition for higher stability. PL2 This includes setting or raising 426. Setting or increasing the liquid pressure of the liquid precursor 228 426 can be achieved using the liquid push pressure control system 510. In one embodiment, the moving pressure of the liquid precursor 228 from the liquid tank 110a can be increased by increasing the pressure of the push gas, which is an inert gas such as hydrogen, helium, argon, or nitrogen, supplied through the push gas line 110b (Figure 2). The increased push pressure in the push gas line 110b can be adjusted by the pressure regulator 224 (Figure 2). In this way P PL2 The liquid precursor 228 that has been moved is delivered to the injection unit 204 through the liquid delivery line 110c.

[0046] Referring to Figure 5, the liquid push pressure control system 510 uses the liquid pressure sensing means 514 and the liquid pressure control means 518 to control the P of the liquid precursor 228 (Figure 2) before it is sprayed into the mixing area 121. PLIt is configured to actively control the system. For example, in response to the detection of a mass flow rate fluctuation outside of manufacturing tolerances using the mass flow meter 132 (Figure 1B), the liquid pressure detection means 514 and the liquid pressure control means 518 automatically or algorithmically adjust the liquid precursor pressure upstream of the liquid injection unit 204 (Figure 2), for example, in the liquid precursor source unit 110, at least in conjunction with the central control unit 550.

[0047] According to a given embodiment, the liquid precursor 228 is P PL2 To deliver controllably to the injection unit 204 which has P PL Setting or increasing the pressure involves adjusting the liquid push gas in the liquid precursor source unit 110 (Figure 2). The pressure regulator 224 can control the liquid push pressure in the liquid delivery line 110c to be within a range defined by 10-50 psia, 10-15 psia, 15-20 psia, 20-25 psia, 25-30 psia, 30-35 psia, 35-40 psia, 40-45 psia, 45-50 psia, or any of these values, for example, between 14 psia and 30 psia, for example, 28 psia.

[0048] Referring further to Figure 4, in other embodiments, operating the liquid precursor delivery unit 112 under higher stability conditions 420 is achieved by the gas pressure (P) downstream of the injection unit 204. PG ) to the first gas pressure (P PG1 A second gas pressure (P) that is higher than ) PG2 ) including setting or raising 428. PG2 This can be achieved, at least in part, by limiting the conductance in the region between the liquid injection unit 204 and the thin film deposition chamber 104 using the downstream pressure control system 540. For example, P PG Raising the P in either the mixing area 212 or the vaporization chamber 216 PG This can be achieved by restricting conductance to locally increase it.

[0049] In the given embodiment, P PG The localized increase can be achieved by increasing the vertical pressure gradient by elongating one or both of the spaces in the mixing area 212 and the vaporization chamber 216 in a vertical direction perpendicular to the surface of the showerhead 113. Elongating one or both of the mixing area 212 and the vaporization chamber 216 may include elongating each space such that the aspect ratio of their vertical length to width or diameter is greater than a value defined by 2:1, 4:1, 6:1, 8:1, 10:1, or any of these values. In another given embodiment, one or both of the mixing area 212 and the vaporization chamber 216 can be controlled so that the local pressure within them is higher than the gas pressure in the thin film deposition chamber 104 (Figure 2) by including a continuously adjustable conductance control means at their lower part, such as a pressure regulator or a butterfly valve.

[0050] 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, for example, in the mixing area 212 and / or vaporization chamber 216, using gas pressure sensing means 544 and gas pressure control means 548. For example, in response to detection of mass flow rate fluctuations outside of manufacturing tolerances using the mass flow meter 132 (Figure 1B), the gas pressure sensing means 544 and gas pressure control means 548 adjust the downstream of the liquid injection unit 204, for example, in the mixing area 212 and / or vaporization chamber 216, at least in conjunction with the central control unit 550, automatically or algorithmically.

[0051] According to various embodiments, during deposition, the total pressure in the thin film deposition chamber 104 may be within the range defined by 0.001.0 to 3.0 Torr, 3.0 to 5.0 Torr, 5.0 to 7.0 Torr, 7.0 to 10.0 Torr, or any of these values. Without substantially reducing the conductance, P PG1These values ​​may be the same or different, and may be within the range defined by 0.001.0 to 3.0 Torr, 3.0 to 5.0 Torr, 5.0 to 7.0 Torr, 7.0 to 10.0 Torr, or any of these values. The downstream pressure control system 540 can be used to set or increase the local pressure in one or both of the mixing area 212 and the vaporization chamber 216 to a value higher than the thin film deposition chamber 104 by a percentage defined by 10%, 20%, 50%, 100%, 200%, 500%, or any of these values, for example, by a value within the range defined by 0.002.0 to 3.0 Torr, 3.0 to 5.0 Torr, 5.0 to 7.0 Torr, 7.0 to 9.0 Torr, 9.0 to 12 Torr, or any of these values.

[0052] ·Applicable The method and system for delivering a vaporized liquid precursor to a thin-film deposition chamber can be implemented in a variety of precursor-based deposition processes. Figures 6A to 6C show thin-film deposition processes in which the liquid precursor delivery method and system according to the embodiment can be implemented. Representative examples of thin-film deposition processes in which the liquid precursor delivery according to the embodiment can be implemented include chemical vapor deposition (Figure 6A), atomic vapor deposition (Figure 6B), and atomic layer deposition (Figure 6C). Each of Figures 6A to 6C is a schematic graph in which the y-axis represents precursor parameters and the x-axis represents time. Precursor parameters can be, for example, precursor flow rate, precursor partial pressure due to precursor introduction, or chamber pressure. Each of Figures 6A to 6C shows a first precursor 610 and a second precursor 620. One or both of the first and second precursors 610 and 620 can be liquid precursors, or one of the first and second precursors 610 and 620 can not be a liquid precursor. For example, the first precursor 610 can be an oxidizing agent precursor, such as O2 or NH3, from the gas panel 116 (Figure 2), and the second precursor can be a liquid precursor 228 (Figure 2), such as a metal precursor. The first and second precursors 610, one or both of them can be introduced together with the carrier gas. Although only two precursors are shown for illustrative purposes, it will be understood that there may be more than two precursors.

[0053] Figure 6A is a schematic graph showing the precursor parameters as a function of time during the deposition of a thin film using a continuous deposition process, such as chemical vapor deposition (CVD). The illustrated continuous deposition process involves introducing a first precursor 610 and a second precursor 620 into the thin film deposition chamber 104 (Figure 2) simultaneously, i.e., in a time-overlapping manner.

[0054] Figure 6C is a schematic graph showing precursor parameters as a function of time during the deposition of a thin film using periodic deposition, such as atomic layer deposition (ALD). The illustrated periodic deposition process involves periodically introducing pulses of a second precursor 620 following pulses of a first precursor 610. The exposure time, or pulse time, of each of the first and second precursors 610 and 620 can be approximately 0.1 to 1 second, 1 to 10 seconds, 10 to 30 seconds, 30 to 60 seconds, or a duration within the range defined by these values. Cycle 310 can be repeated multiple times to deposit the desired thickness of the thin film. The pulses of the first precursor 610 and the second precursor 620 may be accompanied by a purge gas after them or separating them. The purge gas may be continuous or pulsed. Examples of usable purge gases 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 embodiments are not limited thereto, and the cycles may partially overlap. In a given embodiment, the purge pulse may be introduced into the thin film deposition chamber 104 (Figure 2) continuously or as pulses separated by the pulses of the first and second precursors 610 and 620. In yet another embodiment, the pulses of the first precursor 610 and the second precursor 620 may be separated by pump exhaust without a purge gas.

[0055] Figure 6B is a schematic graph showing precursor parameters as a function of time during the deposition of a thin film using hybrid deposition, such as atomic vapor deposition (AVD). The illustrated hybrid deposition process includes introducing the first precursor 610 continuously or as a pulse spanning at least one pulse of the second precursor 620, while periodically introducing pulses of the second precursor 620. The exposure time of the second precursor 620 and the first precursor 610, i.e., the pulse time, when pulsed, can be a duration within the range defined by approximately 0.1 to 1 second, 1 to 10 seconds, 10 to 30 seconds, 30 to 60 seconds, or any of these values. In the illustrated embodiment, the first precursor 610 spans multiple pulses of the second precursor. However, the embodiment is not limited thereto, 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 gas or a purge gas. The purge gas 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.

[0056] A method and system for delivering a liquid precursor to a thin film deposition chamber can be configured, in particular, for liquid precursors containing 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. The liquid precursor for metals can be a metal halide or an organometallic compound such as a metal β-diketonate, metal cyclopentadienyl, metal alkoxide, metal alkyl, or metal alkylamide, depending on the organic complex related to the metal. The liquid precursor may be in liquid form or a solid precursor dissolved in a solvent. Among the compounds, the liquid precursor can be used for the formation of metal oxides, metal nitrides, compound semiconductors, chalcogenides, fluorides, and elemental metals.

[0057] Figure 7 shows an experimental graph of the mass flow rate measured as a function of time for a liquid precursor introduced in pulse mode using the delivery method according to the embodiment. The y-axis represents the flow rate in standard cubic centimeters per minute (sccm), and the x-axis represents time (hours:minutes:seconds). In the illustrated example, the duration of the liquid precursor pulse is approximately 60 seconds. For each pulse of the liquid precursor, after the initial transient spike corresponding to the opening of the injection point of the liquid precursor delivery unit 112 (Figure 2), the mass flow rate within the pulse is extremely constant, and the reproducibility between pulses is also good. As described above, in periodic precursor exposure as in the illustrated example, the duration that defines the manufacturing tolerance can be the duration of a single pulse, or the sum of multiple depositions. In the illustrated example, the duration can exclude the initial spike when the liquid precursor delivery unit 112 (Figure 2) is first activated.

[0058] While this specification has described the present invention with reference to specific embodiments, these embodiments are not intended to limit the invention but are described for illustrative purposes only. It will be obvious to those skilled in the art that modifications and improvements can be made without departing from the spirit and scope of the invention.

[0059] Such simple modifications and improvements to the various embodiments disclosed herein fall within the scope of the disclosed technology, and the specific scope of the disclosed technology will be further defined by the appended claims.

[0060] It will be understood that any feature of any one embodiment can be combined with or substituted for any other feature of any one of the embodiments.

[0061] Unless the context clearly requires otherwise, throughout this specification and the claims, words such as “comprise,” “comprising,” “include,” and “include” shall be interpreted in a comprehensive sense, i.e., “include but not limit,” rather than in an exclusive or exhaustive sense. The term “coupled,” as commonly used herein, refers to two or more elements that are either directly connected or connected via one or more intermediate elements. Similarly, the term “connected,” as commonly used herein, refers to two or more elements that are either directly connected or may be connected via one or more intermediate elements. Furthermore, “this specification,” “above,” “below,” and similar terms, when used in this application, refer to the entire application and not to any particular part thereof. Where the context allows, words used in the above detailed descriptions with singular or plural numbers may also include plural or singular numbers. The word "or" when referring to a list of two or more items can be interpreted as encompassing any of the items in the list, all items in the list, or any combination of items in the list.

[0062] Furthermore, conditional language used herein, particularly "can," "could," "might," "may," "eg," "for example," and "such as," is generally intended to convey that a particular embodiment includes certain features, elements, and / or states, while other embodiments do not, unless otherwise specified or understood to have a different meaning in the context in which they are used. Therefore, such conditional language is not generally intended to suggest that features, elements, and / or states are required in any way in one or more embodiments, or that these features, elements, and / or states are included in or performed in any particular embodiment.

[0063] While specific embodiments have been described, these embodiments are presented for illustrative purposes only and are not intended to limit the scope of this disclosure. In fact, novel devices, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions, and modifications in the forms of methods and systems described herein may be made without departing from the spirit of this disclosure. For example, while functions are shown in a given arrangement, in alternative embodiments, similar functions may be performed with different component and / or sensor topologies, and some functions may be deleted, moved, added, subdivided, combined, and / or modified. Each of these features may be implemented in a variety of different ways. Any suitable combination of elements and operations of the various embodiments described above may be combined to provide further embodiments. The various features and processes described above may be implemented independently of each other or combined in a variety of ways. All possible combinations and subcombinations of the features of this disclosure are intended to be included within the scope of this disclosure.

Claims

1. A method for delivering a liquid precursor into a thin film deposition chamber using a liquid precursor delivery unit, A liquid precursor delivery unit is provided, which includes a liquid injection unit, a mixing area, and a vaporization chamber. This includes delivering a vaporized liquid precursor into the thin film deposition chamber under lower stability conditions, including a first liquid precursor temperature in 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. Under lower stability conditions than those described above, the first mass flow rate of the liquid precursor fluctuates by more than 10% relative to the average mass flow rate of the liquid precursor during the first duration. This involves delivering the vaporized liquid precursor into the thin film deposition chamber under higher stability conditions, including a second liquid precursor temperature in the liquid injection unit that is lower than the first liquid precursor temperature, by cooling the second liquid precursor in the liquid injection unit by at least partially by at least 5°C. Under the aforementioned higher stability conditions, the second mass flow rate of the liquid precursor fluctuates less than the first mass flow rate and fluctuates by less than 10% of the average mass flow rate during the second duration, which has the same duration as the first duration. Delivering the vaporized liquid precursor into the thin film deposition chamber under lower and higher stability conditions respectively includes atomizing the liquid precursor into atomized precursor droplets using the liquid injection unit, mixing the atomized precursor droplets with a transport gas in the mixing area, and vaporizing the atomized precursor droplets into the vaporized liquid precursor in the vaporization chamber. Delivering the vaporized liquid precursor into the thin film deposition chamber under the above-mentioned higher stability conditions further includes heating the transport gas by at least 5°C, thereby including the mixing of heated transport gas formed by the heating of the transport gas and cooled atomized precursor droplets formed by the cooling of the liquid precursor. A method wherein the temperature of the mixture of the atomizing precursor droplets formed from the liquid precursor and the heated transport gas at the second liquid precursor temperature is substantially the same as the temperature of the mixture of the atomizing precursor droplets formed from the liquid precursor and the transport gas before heating at the first liquid precursor temperature.

2. The method according to claim 1, wherein the higher stability condition further includes a second liquid precursor pressure upstream of the liquid injection unit, which is higher than the first liquid precursor pressure, and the second liquid precursor pressure is at least partially generated by setting a liquid push pressure upstream of the liquid injection unit.

3. The method according to claim 2, wherein setting the liquid push pressure upstream of the liquid injection unit includes adjusting the liquid push gas in the liquid precursor source unit that stores the liquid precursor.

4. The method according to claim 3, wherein adjusting the liquid push gas includes adjusting the liquid push pressure to a level higher than 14 psi, and the liquid push pressure before adjustment is less than 14 psi.

5. The method according to claim 1, wherein the higher stability condition further includes a second gas pressure downstream of the liquid injection unit which is higher than the first gas pressure, and the second gas pressure is higher than the pressure in the thin film deposition chamber.

6. The method according to claim 5, wherein the second gas pressure downstream of the liquid injection unit is generated at least partially by limiting the conductance between the liquid injection unit and the thin film deposition chamber.

7. The method according to claim 6, wherein limiting the conductance includes extending one or both of the mixing area and the vaporization chamber in the length direction with respect to the width direction so that they have an aspect ratio greater than 1:

1.

8. The method according to claim 6, wherein limiting the conductance includes adjusting a valve or regulator.

9. The method according to claim 6, wherein the second gas pressure is at least 10% higher than the first gas pressure.

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

11. The method according to claim 1, wherein the durations of the first and second periods exceed 10 seconds.

12. The method according to claim 1, wherein delivering the vaporized liquid precursor under each of the lower and higher stability conditions comprises delivering pulses of the vaporized liquid precursor to deposit a thin film by a periodic deposition process.

13. The method according to claim 1, wherein delivering the liquid precursor under each of the lower stability conditions and the higher stability conditions comprises continuously delivering the liquid precursor to deposit a thin film by a continuous deposition process.

14. A method for delivering a liquid precursor into a thin film deposition chamber, A liquid precursor delivery unit is provided, configured to deliver the vaporized liquid precursor into the thin film deposition chamber by atomizing the liquid precursor into atomized precursor droplets using a liquid injection unit and then vaporizing the atomized precursor droplets into vaporized liquid precursors in a vaporization chamber; Delivering the vaporized liquid precursor into the thin film deposition chamber under lower stability conditions, including a first liquid precursor temperature in 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; To detect a first mass flow rate fluctuation of the liquid precursor exceeding 10% of the average mass flow rate of the liquid precursor during a first duration; The process includes delivering the vaporized liquid precursor into the thin film deposition chamber under higher stability conditions, including a second liquid precursor temperature in the liquid injection unit, which is lower than the first liquid precursor temperature, resulting from cooling the liquid precursor in the liquid injection unit by at least partially by at least 5°C; Under the aforementioned higher stability conditions, the second mass flow rate of the liquid precursor fluctuates by less than 10% of the average mass flow rate during a second duration having the same duration as the first duration. Delivering the vaporized liquid precursor into the thin film deposition chamber under lower and higher stability conditions respectively includes mixing the atomized precursor droplets with a heated carrier gas before vaporizing the atomized precursor droplets, and A method wherein the temperature of the mixture of the atomizing precursor droplets formed from the liquid precursor and the heated transport gas at the second liquid precursor temperature is substantially the same as the temperature of the mixture of the atomizing precursor droplets formed from the liquid precursor and the transport gas before heating at the first liquid precursor temperature.

15. The method according to claim 14, wherein the higher stability condition further includes a second liquid precursor pressure upstream of the liquid injection unit which is higher than the first liquid precursor pressure, and the second liquid precursor pressure is at least partially achieved by setting a liquid push pressure upstream of the liquid injection unit storing the liquid precursor.

16. The method according to claim 15, wherein the liquid push pressure is set to exceed 14 psi, and the liquid push pressure under lower stability conditions is less than 14 psi.

17. The method according to claim 14, wherein the higher stability condition further includes a second gas pressure downstream of the liquid injection unit that is higher than the first gas pressure, and the second gas pressure downstream of the liquid injection unit is higher than the pressure in the thin film deposition chamber.

18. The method according to claim 17, wherein the second gas pressure downstream of the liquid injection unit is generated at least partially by limiting the conductance between the liquid injection unit and the thin film deposition chamber such that the second gas pressure is at least 10% higher than the first gas pressure.

19. The method of claim 14, wherein delivering the vaporized liquid precursor under each of the lower stability conditions and the higher stability conditions comprises delivering pulses of the liquid precursor to deposit a thin film by a periodic deposition process.

20. The method of claim 14, wherein delivering the vaporized liquid precursor under each of the lower and higher stability conditions comprises continuously delivering the liquid precursor to deposit a thin film by a continuous deposition process.

Images