Precursor delivery system and method for high rate cyclic deposition - Patents.com

Abstract

The disclosed technology relates generally to semiconductor manufacturing, and more particularly to precursor delivery in cyclic deposition. In one aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternating exposure of a substrate to multiple precursors. The thin film system additionally includes a precursor source connected to the thin film deposition chamber by a precursor delivery line, the precursor delivery line including a high conductance line portion between the precursor source and a final valve external to the thin film deposition chamber. The high conductance line portion extends in a flow direction and has at least four times the conductance of either of the adjacent low conductance line portions connected to the opposite end of the high conductance line portion. The thin film system further includes a single final valve between the high conductance line portion and the thin film deposition chamber.

Description

[Technical field]

[0001] Incorporation by Reference of Priority Application Any and all applications for which foreign or domestic priority is identified in an Application Data Sheet filed with this application are hereby incorporated by reference pursuant to 37 CFR §1.57.

[0002] This application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 149,039, filed February 12, 2021, and entitled “HIGH CONDUCTANCE PRECURSOR DELIVERY SYSTEM FOR CYCLIC DEPOSITION,” the entire contents of which are expressly incorporated herein by reference.

[0003] The disclosed technology relates generally to semiconductor manufacturing, and more particularly to precursor delivery in cyclic deposition. [Background technology]

[0004] As the lateral dimensions of semiconductor devices continue to shrink, there is a corresponding decrease in the vertical dimensions of the semiconductor devices, including a decrease in the thickness of functional thin films such as electrodes and dielectrics. Semiconductor fabrication involves a variety of thin films that are deposited throughout the process flow. The various thin films can be deposited using different techniques, including wet and dry deposition methods. Wet deposition methods include, for example, aerosol / spray deposition, sol-gel techniques, and spin-coating. Dry deposition methods include physical vapor deposition-based techniques, such as physical vapor deposition (PVD) and evaporation. Dry deposition methods additionally include precursor and / or chemical reaction-based techniques, such as chemical vapor deposition (CVD), and cyclic deposition, such as atomic layer deposition (ALD). Summary of the Invention [Means for solving the problem]

[0005] In a first aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternatingly exposing a substrate to a plurality of precursors. The thin film system additionally includes a precursor source connected to the thin film deposition chamber by a precursor delivery line, the precursor delivery line including a high conductance line portion between the precursor source and the thin film deposition chamber. The high conductance line portion extends in a flow direction and has at least four times the conductance of either of the adjacent low conductance line portions connected to the opposite end of the high conductance line portion. The thin film system further includes a single final valve between the high conductance line portion and the thin film deposition chamber.

[0006] In a second aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternatingly exposing a substrate to a plurality of precursors. The thin film system additionally includes a precursor source connected to the thin film deposition chamber by a precursor delivery line, the precursor delivery line including a high conductance line portion between the precursor source and a final valve external to the thin film deposition chamber. The high conductance line portion extends in a flow direction and has at least four times the conductance of either of the adjacent low conductance line portions connected to the opposite end of the high conductance line portion. The system is configured such that during exposure of the substrate to the precursor at the precursor source, the precursor flows continuously from the precursor source through the high conductance line portion to the thin film deposition chamber without interruption by the actuation of another valve.

[0007] In a third aspect, a thin film deposition system includes multiple processing stations sharing a thin film deposition chamber. Each processing station includes a gas distribution plate, a susceptor, and a lid sealing the thin film deposition chamber. The thin film deposition system additionally includes a precursor source connected to the thin film deposition chamber by a precursor delivery line, the precursor delivery line including a high conductance line portion between the precursor source and a final valve outside the thin film deposition chamber. The high conductance line portion extends in a flow direction and has at least four times the conductance of either of the adjacent low conductance line portions connected to the opposite end of the high conductance line portion.

[0008] In a fourth aspect, a method of depositing a thin film includes providing a thin film deposition system including a high conductance line portion as part of a precursor delivery line between a precursor source and a final valve external to the thin film deposition chamber, the high conductance line portion extending in a flow direction and having at least four times the conductance of either of the adjacent low conductance line portions connected to opposite ends of the high conductance line portion. The method additionally includes alternatingly exposing a substrate in the thin film deposition chamber to a plurality of precursors in a plurality of cycles. Alternatingly exposing the substrate includes pressurizing the high conductance line portion to a first pressure with a first one of the precursors with the final valve closed, and opening the final valve for a period of time such that the pressure in the high conductance line portion remains above a second pressure that is less than 10% lower than the first pressure.

[0009] In a fifth aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternately exposing a substrate to a plurality of precursors. The thin film deposition system further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line. The precursor delivery line includes an increased conductance portion disposed between the precursor source and the thin film deposition chamber, the increased conductance portion serving as an intermediate precursor reservoir having a volume greater than 0.3 L.

[0010] In a sixth aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternatingly exposing a substrate to a plurality of precursors. The thin film deposition system further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line. The precursor delivery line includes an increased conductance portion disposed between the precursor source and the thin film deposition chamber that serves as an intermediate precursor reservoir having a diameter greater than 0.5 inches.

[0011] In a seventh aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternatingly exposing a substrate to a plurality of precursors. The thin film deposition system further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line for delivering one of the precursors into the thin film deposition chamber. The precursor delivery line includes an increased conductance portion acting as an intermediate precursor reservoir configured such that an exposure time to one of the precursors to reach substantial substrate surface saturation is reduced by more than 50% relative to an exposure time to one of the precursors to reach substantial substrate surface saturation without the increased conductance portion.

[0012] In an eighth aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternating exposure of a substrate to a plurality of precursors. The thin film deposition chamber further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line for delivering one of the precursors into the thin film deposition chamber. The precursor delivery line includes an increased conductance section acting as an intermediate precursor reservoir configured such that the exposure time to one of the precursors to reach substantial substrate surface saturation is less than ½ second.

[0013] In a ninth aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternately exposing a substrate to a plurality of precursors. The thin film deposition system further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line for delivering one of the precursors into the thin film deposition chamber. The precursor delivery line includes an increased conductance portion acting as an intermediate precursor reservoir configured to open a valve to introduce one of the precursors into the thin film deposition chamber, resulting in a pressure drop within the intermediate precursor reservoir of not more than 50 Torr.

[0014] In a tenth aspect, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternating exposure of a substrate to a plurality of precursors. The thin film deposition system includes a precursor source connected to the thin film deposition chamber by a precursor delivery line for delivering one of the precursors into the thin film deposition chamber. The precursor delivery line includes an intermediate precursor reservoir serving as an intermediate precursor reservoir configured such that a thin film deposited in a high aspect ratio trench or via having an aspect ratio greater than 2 has step coverage defined as a ratio of a thickness of the thin film formed on a lower half of a sidewall of the high aspect ratio trench or via to a thickness of the thin film formed on an upper half of a sidewall of the high aspect ratio trench or via that is at least 10% higher than the step coverage of a thin film deposited at the high aspect ratio without the conductance-increasing portion.

[0015] In an eleventh aspect, a thin film deposition system includes a thin film deposition chamber including a plurality of process stations each configured to deposit a thin film by alternatingly exposing a substrate to a plurality of precursors. The thin film deposition system further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line. The precursor delivery line includes an increased conductance section that serves as an intermediate precursor reservoir having a volume greater than 0.3 L. The precursor delivery line is connected at a first end to the precursor source and at a second end is divided into a plurality of local precursor delivery lines that deliver one of the precursors into each process station. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram illustrating a thin film deposition system including a thin film deposition chamber and a precursor delivery system configured with a precursor delivery line including a high conductance line portion, according to an embodiment.

[0017] [Figure 2A] FIG. 1 is a perspective view of a lid portion of a deposition chamber including multiple processing stations configured to introduce precursors through conventional precursor delivery lines.

[0018] [Figure 2B] FIG. 13 is a perspective view illustrating a lid portion of a deposition chamber including multiple processing stations configured to introduce precursors through a precursor delivery line having a high conductance line portion, according to an embodiment.

[0019] [Figure 2C] FIG. 2C is a perspective view showing a precursor delivery line with a high conductance line section for the deposition chamber shown in Figure 2B.

[0020] [Diagram 3]13 is an experimental graph showing precursor volumes delivered to a process chamber using successive exposure pulses for different high conductance line sections having different volumes.

[0021] [Figure 4A] FIG. 1 shows experimental measurements of pressure change in a precursor delivery line that does not have a high conductance line section when an atomic layer deposition (ALD) valve is opened to introduce precursor into a thin film process chamber. [Figure 4B] FIG. 1 shows experimental measurements of pressure change in a precursor delivery line with a high conductance line section when an atomic layer deposition (ALD) valve is opened to introduce precursor into a thin film process chamber.

[0022] [Figure 5A] FIG. 1 illustrates a perspective view of a multi-valve block assembly for a precursor delivery system configured with precursor delivery lines having high conductance line sections, according to an embodiment.

[0023] [Figure 5B] FIG. 5B is a perspective view illustrating one of the multi-valve blocks shown in FIG. 5A configured to couple multiple ALD valves to a common gas distribution plate, according to an embodiment.

[0024] [Figure 5C] FIG. 5C is a perspective view illustrating one of the ALD valves configured to couple to the multi-valve block shown in FIG. 5B, according to an embodiment.

[0025] [Figure 5D] 5D is an example experimental chart showing various signals associated with the actuation of an ALD valve such as that shown in FIG. 5C, in accordance with an embodiment.

[0026] [Figure 6]1 is a schematic diagram illustrating an example precursor delivery sequence for delivering precursors using a precursor delivery system, according to an embodiment.

[0027] [Figure 7] FIG. 2 is a schematic cross-sectional view showing a via lined with a thin film layer having different thicknesses in different portions of the via.

[0028] [Figure 8A] FIG. 13 illustrates step coverage values ​​measured in high aspect ratio structures as a function of pressure in a high conductance line portion of a precursor delivery line constructed in accordance with an embodiment.

[0029] [Figure 8B] 10A-10C show step coverage values ​​measured on high aspect ratio structures for various process conditions achieved using a precursor delivery line configured in accordance with an embodiment.

[0030] [Figure 8C] FIG. 13 illustrates pressure fluctuations in a high inductance line portion of a precursor delivery line during cyclic deposition, according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Cyclic deposition processes such as atomic layer deposition (ALD) processes can provide relatively conformal thin films on relatively high aspect ratio (e.g., 2:1) structures with high uniformity and thickness precision. Although the conformality and uniformity is generally lower compared to ALD, thin films deposited using sequential deposition processes such as chemical vapor deposition (CVD) can provide higher productivity at lower cost. ALD and CVD have been used to fabricate a wide variety of thin films, including elemental metals, metal compounds (e.g., TiN, TaN, etc.), semiconductors (e.g., Si, III-V, etc.), dielectrics (e.g., SiO2, AlN, HfO2, ZrO2, etc.), rare earth oxides, conductive oxides (e.g., IrO2, etc.), ferroelectrics (e.g., PbTiO3, LaNiO3, etc.), superconductors (e.g., YBa2Cu3O, etc.), to name a few. 7-x ), as well as chalcogenides (eg, GeSbTe).

[0032] Some cyclic deposition processes, such as atomic layer deposition (ALD), involve exposing a substrate to multiple precursors in alternating fashion to form a thin film. The different precursors can alternately at least partially saturate the surface of the substrate and react with each other, thereby forming a thin film layer by layer. The ability to grow layer by layer allows ALD to precisely control thickness and composition, which can allow precise control over a variety of properties, such as electrical conductivity, conformality, uniformity, barrier properties, and mechanical strength. Due to the nature of the deposition process in ALD, the precursor delivery system of an ALD deposition system faces unique challenges compared to, for example, the precursor delivery system of a CVD deposition system. For example, because the alternating exposure of a substrate to multiple precursors is performed repeatedly at a relatively high rate and / or frequency, the precursor delivery system, or components of the system, such as precursor delivery line valves, can directly or indirectly impose significant limitations on various aspects of the ALD deposition process, such as precision, throughput, reliability, and operational costs. Since deposition of thin films by ALD can involve a few to thousands of cycles of alternating exposure to different precursors, the number, duration, and frequency of alternating exposure of the substrate to multiple precursors are directly proportional to the throughput. The number, duration, and frequency of exposures can in turn be limited by system components, such as the precursor delivery system, or precursor delivery line configuration. In particular, the conductance, volume, and pressure stability of the precursor delivery line can directly affect the deposition throughput, the efficiency of precursor usage, and the quality of the resulting thin film. Therefore, there is a need for improved precursor delivery systems with fast valves and delivery lines adapted for high conductance, large volume, and high pressure stability to increase throughput, as well as to improve film quality, such as high step coverage, conformality, and uniformity.

[0033] Precursor delivery system with high conductance precursor delivery line To address the above-mentioned needs among others, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternating exposure of a substrate to multiple precursors. The thin film deposition system further includes a precursor source connected to the thin film deposition chamber by a precursor delivery line. The precursor delivery line includes an increased conductance or high conductance line section that acts as an intermediate precursor reservoir disposed between the precursor source and the thin film deposition chamber. This configuration allows for increased precursor usage per cycle of substrate exposure in the process chamber, thereby significantly reducing precursor exposure time until substantial substrate surface saturation by the precursor is reached. This configuration also allows for increased stability of the precursor delivered into the process chamber. For example, this configuration allows for increased usage while reducing pressure fluctuations in the delivery line by providing an intermediate precursor reservoir that acts as a high conductance buffer between the thin film deposition chamber and the precursor source. This configuration may be particularly advantageous for process chambers having multiple process stations that may use much larger amounts of precursor and purge gas. Increasing the usage and stability of precursors delivered by the precursor delivery system with purge gas embodiments can advantageously improve thin film step coverage and uniformity of high aspect ratio structures.

[0034] As described herein, a high conductance line section refers to a delivery line section extending in the flow direction, with first and second ends serving as an inlet and an outlet, respectively. The high conductance line section has a greater conductance or volume per length than adjacent line sections connected to both ends. For example, the high conductance line section may have a cylindrical shape with a length greater than its diameter. The inventors have found that this configuration of the high conductance line section is advantageous in that it functions as an intermediate reservoir while optimizing the conductance of the gas flowing therethrough. For example, a reservoir or tank with an inlet and an outlet disposed on the same side may function as a reservoir, but such a configuration may reduce the conductance of the gas passing therethrough.

[0035] As described herein, atomic layer deposition (ALD) valves have high accuracy and speed (e.g., response times of less than 30 ms) and high flow coefficients (e.g., C greater than 0.20). v ) into the ALD deposition chamber. Because deposition of thin films by ALD can involve a few to thousands of cycles of alternating exposure to different precursors, valve parameters such as flow rate, speed, and / or frequency of the ALD valve can directly affect the deposition throughput as well as the efficiency of the precursor specifications. In addition, wear on the ALD valve can limit the useful life of some ALD systems between preventive maintenance services. Furthermore, some precursors delivered at high temperatures can limit the throughput and modal life of some ALD systems.

[0036] Hereinafter, embodiments may be described using specific precursors. For example, specific example precursors including TiCl4, NH3, and SiCl2H2 for depositing TiN and / or TiSiN may be used to describe a thin film deposition system of a method for depositing a thin film. However, it is understood that the embodiments are not so limited, and aspects of the invention may be applied to any suitable combination of precursors to deposit any suitable thin film that can be formed using a cyclic deposition process such as ALD.

[0037] Hereinafter, embodiments may be described using specific precursors for specific films as examples. For example, specific example precursors including TiCl4, NH3, and SiCl2H2 for depositing TiN and / or TiSiN may be used to describe thin film deposition systems and methods for depositing thin films according to various embodiments. However, it will be understood that the embodiments are not so limited, and aspects of the invention may be applied to any suitable combination of precursors to deposit any suitable thin film that can be formed using a cyclic deposition process such as ALD.

[0038] FIG. 1 illustrates a schematic of a thin film deposition system including a thin film deposition chamber and a precursor delivery system configured with a precursor delivery line including a high conductance line portion, according to an embodiment. The thin film deposition system 100 includes a thin film deposition chamber 102 and a precursor delivery system 106 configured to deliver a plurality of precursors into the deposition chamber 102. The illustrated deposition chamber 102 is configured to process a substrate 120, e.g., a wafer, on a support 116, e.g., a susceptor, under process conditions. The deposition chamber 102 additionally includes a nozzle 108 that centrally releases a plurality of precursors into the deposition chamber 102 through a gas distribution plate 112, also referred to as a showerhead. The nozzle 108 may mix gases, e.g., precursors and a purge gas, which are then diffused into the deposition chamber 102 by the gas distribution plate 112. The gas distribution plate 112 is configured to uniformly diffuse the precursors over the substrate 120 on the susceptor 116 to provide a uniform deposition. The deposition chamber may be equipped with a pressure monitoring sensor (P) and / or a temperature monitoring sensor (T).

[0039] The precursor delivery system 106 is configured to deliver multiple precursors from precursor sources (120, 124) and one or more purge gases, e.g., inert gases, from purge gas sources (128-1, 128-2, 134-1, 134-2) into the process chamber. Each of the precursors and purge gases is connected to the deposition chamber 102 by a respective gas delivery line. Advantageously, at least some of the gas delivery lines may comprise an increased conductance line section that serves as an intermediate gas reservoir between the precursor source or the purge gas source and the thin film deposition chamber 102. The gas delivery lines additionally include in their path a mass flow controller (MFC) 132 and a respective precursor valve that introduces the respective precursor into the thin film deposition chamber. Further advantageously, at least some of the valves can be atomic layer deposition (ALD) valves. The gas delivery lines are connected to the deposition chamber 102 through a gas distribution plate 112.

[0040] For illustrative purposes only, in the illustrated configuration of Fig. 1, the multiple precursors include a first precursor and a second precursor. The first precursor is stored in at least one first precursor source 120, and the second precursor is stored in at least one second precursor source 124. The precursor delivery system 106 is configured to deliver the first and second precursors from the first and second precursor sources 120, 124, respectively, through first and second precursor delivery lines 110, 114 into the deposition chamber 102. The first and second precursor delivery lines 110, 114 include high conductance line sections 130, 134, respectively. A rapid purge (RP) gas can be stored in at least two RP gas sources 128-1, 128-2. The precursor delivery system 106 is configured to deliver a rapid purge (RP) gas from the RP gas sources 128-1, 128-2 into the deposition chamber 102 through the RP gas delivery lines 118-1, 118-2, respectively. The RP gas delivery lines 118-1, 118-2 each include a high conductance line portion 138-1, 138-2. The continuous purge (CP) gas can be stored in at least two CP gas sources 134-1, 134-2. The precursor delivery system 106 is configured to deliver a CP gas from the CP gas sources 134-1, 134-2 into the deposition chamber 102 through the CP gas delivery lines 114-1, 114-2, respectively.

[0041] The first and second precursors are configured to be delivered from first and second precursor sources 120, 124, respectively, by independently operating first and second precursor ALD valves 140 and 144, which are connected in parallel to a common gas distribution plate 112. In addition, a RP purge gas is configured to be delivered from RP purge gas sources 128-1, 128-2, which are connected in parallel to a common gas distribution plate 112, by independently operating two purge gas ALD valves 148-1, 148-2, which are connected in parallel to a common gas distribution plate 112. The ALD valves 140, 144, 148-1, and 148-2 and respective delivery lines connected to the gas distribution plate 112 can be arranged to feed the respective gases into the nozzle 108 through a multi-valve block assembly 150 ( FIG. 5A ), which may be attached to the lid of the deposition chamber 102. In the illustrated configuration, ALD valves 140, 144, 148-1, and 148-2 are the final valves before the respective gases are introduced into deposition chamber 102.

[0042] By way of example only, the first and second precursors can include TiCl4 and NH3, respectively, which are delivered from respective TiCl4 and NH3 sources through respective precursor delivery lines into the deposition chamber 102 to form, for example, TiN. The precursor delivery system can additionally be configured to deliver Ar as a purge gas from an Ar source through a purge gas delivery line into the process chamber. The purge gas can be delivered as a continuous purge (CP) gas, which may be delivered through a precursor ALD valve, and / or as a fast purge (RP) gas, which may be delivered through a dedicated purge gas ALD valve as shown in FIG. 1. The illustrated precursor delivery system 100 can be configured to deliver Ar as a RP gas from purge gas sources 128-1, 128-2 through respective purge gas delivery lines and purge gas ALD valves 148-1, 148-2 into the process chamber 102.

[0043] According to various embodiments, the thin film deposition system 100 is configured for thermal ALD without utilizing plasma. Although plasma-enhanced processes such as plasma-enhanced atomic layer deposition (PE-ALD) can be effective for forming conformal films on surfaces with relatively low aspect ratios, such processes may not be effective for depositing films inside vias and cavities with relatively high aspect ratios. Without being limited by theory, one possible reason for this is that in some circumstances, the plasma may not reach the deeper portions of high aspect ratio vias. In these circumstances, different portions of the via may be exposed to different amounts of plasma, which may result in undesirable structural effects from the non-uniform deposition, such as thicker films deposited near the via opening compared to deeper portions (sometimes referred to as cusp formation or keyhole formation). For these reasons, thermal cyclic vapor deposition such as thermal ALD may be more advantageous, since such thermal processes do not depend on the plasma being able to reach the portions of the surface where deposition occurs.

[0044] The illustrated precursor delivery system 100 increases the flow rate and stability of precursors delivered into the deposition chamber 102, in part, due to the presence of high conductance line sections in the delivery lines. The inventors have discovered that achieving short precursor exposure times without sacrificing stability can be particularly challenging for process chambers having multiple process stations, such as those described herein (e.g., FIGS. 2A, 2B), due to the large combined volumes of precursors delivered to the multiple process stations.

[0045] FIG. 2A illustrates an example base deposition chamber that may particularly benefit from various embodiments disclosed herein, including high conductance line portions and ALD valves. FIG. 2A illustrates a perspective view of a lid portion 210 of a deposition chamber 200A that includes multiple processing stations. Each processing station is configured to process substrates under unique processing conditions, including process temperatures, process pressures, and precursor combinations. In the illustrated embodiment, there are four processing stations with corresponding lids 112-1, 112-2, 112-3, 112-4. The processing stations can be, for example, single substrate processing stations, each configured to deliver one or more precursors through a respective precursor delivery line. While the illustrated process chamber is a multi-station process chamber, it will be appreciated that the embodiments disclosed herein are not so limited and may be implemented in any suitable single wafer or multi-wafer process chamber. The illustrated upper portions of lids 112-1, 112-2, 112-3, 112-4 are physically external to deposition chamber 102 (FIG. 1). Inside the process chamber, lids 112-1, 112-2, 112-3, 112-4 each include or are attached to a gas distribution plate (not shown), also called a showerhead, configured to diffuse precursors over a substrate on a susceptor.

[0046] Each processing station may be configured, for example, in a manner similar to that described above with respect to FIG. 1, and may include a respective one of lids 112-1, 112-2, 112-3, 112-4. Returning to FIG. 1, after each one of the MFCs, each of the gas delivery lines may branch into multiple lines at a respective manifold 136. Each of the branched lines may supply a respective gas to one of the processing stations. For example, feeding each lid are four gas lines, e.g., ¼ inch lines, which may correspond to gas delivery lines 118-1, 114-1, 110, and 114 as described above with respect to FIG. 1. The illustrated deposition chamber includes one or more processing stations, each configured to process a substrate on a support, e.g., a susceptor, under process conditions, in a manner similar to that described above with respect to FIG. 1.

[0047] An example base deposition chamber, such as that shown in FIG. 2A, can particularly benefit from various combinations of the embodiments disclosed herein, including high conductance line sections and ALD valves, allowing for significantly shorter exposures to each precursor without sacrificing desirable film properties such as conformality, step coverage, and uniformity.

[0048] High Conductance Line Section for High Speed ​​Cyclic Deposition System Various combinations of features that enable high-rate cyclic deposition disclosed herein include high conductance line sections that act as intermediate reservoirs with high conductance and high flow rates therethrough. FIG. 2B shows a perspective view of a deposition chamber lid section with multiple processing stations configured to introduce precursors through precursor delivery lines with high conductance line sections, according to embodiments. The lid section 210 of deposition chamber 200B can represent one example of the lid section 210 described in FIG. 2A in which various features, including high inductance line sections and ALD valves, according to various embodiments, are implemented. For clarity, FIG. 2C shows a perspective view of a precursor delivery line with high conductance line sections for the processing chamber shown in FIG. 2B, without other components.

[0049] The illustrated lid portion 210 of the deposition chamber 200B includes base components similar to those of the lid portion 210 of the deposition chamber 200A described above with respect to FIG. 2A, and for brevity, those details will not be repeated herein. For example, the deposition chamber 200B of the lid portion includes lids 112-1, 112-2, 112-3, 112-4, each equipped with a precursor delivery system that delivers a plurality of precursors and one or more purge gases. Each of the precursors and purge gases are connected to the deposition chamber 200B by a respective gas delivery line. Each of the delivery lines is connected to a respective gas source at one end, as described above with respect to the thin film deposition system shown in FIG. 1. On the other hand, the delivery lines are divided into four local delivery lines connected to ALD valves, which in turn are connected to the showerhead processing station.

[0050] In the thin film deposition chamber 200A shown in FIG. 2A, the gas delivery lines may be standard gas lines, having a diameter that can be constant throughout the gas delivery lines, for example, 0.25 to 0.5 inches. Unlike the gas delivery lines of the thin film deposition chamber shown in FIG. 2A, at least some of the gas delivery lines shown in FIG. 2B, according to various embodiments, include increased conductance line sections that function as intermediate gas reservoirs between the precursor or purge gas sources and the thin film deposition chamber 200B.

[0051] Referring to FIG. 2B in conjunction with FIG. 2C for clarity, high conductance line sections are disposed between each gas source and the thin film deposition chamber before the gas delivery line branches into local delivery lines that deliver gas into multiple processing stations.

[0052] 2B and 2C, the illustrated thin film deposition chamber 200B and precursor delivery system 200C are configured to deliver three different precursors and a fast purge gas through respective gas delivery lines including high conductance line portions. In a manner similar to that described above with respect to FIG. 1, the first, second, and third precursors (Prec. 1, Prec. 2, Prec. 3) are stored in respective first, second, and third precursor sources (not shown). In a manner similar to that described above with respect to the precursor delivery system 106 (FIG. 1), the precursor delivery system 200C is configured to deliver the first, second, and third precursors (Prec. 1, Prec. 2, Prec. 3) from the first, second, and third precursor sources, respectively, through the first, second, and third precursor delivery lines 210, 214, and 228 into the deposition chamber 102 (FIG. 1). The first, second, and third precursor delivery lines 210, 214, and 228 each include a respective high conductance line portion 230, 234, and 238. The high conductance line portions 230, 234, and 238 are fitted with pressure monitoring sensors 230P, 234P, and 238P, respectively. In addition, a fast purge (RP) gas can be stored in a respective RP gas source (not shown). In a manner similar to the precursor delivery system 106 (FIG. 1) described above, the precursor delivery system 200C is configured to deliver an RP gas from a RP gas source into the deposition chamber 102 (FIG. 1) through a respective one of the RP gas delivery lines 218-1, 218-2. The RP gas delivery lines 218-1, 218-2 each include a high conductance line portion 228-1, 228-2.

[0053] According to various embodiments, high conductance delivery line sections functioning as intermediate gas reservoirs are included as at least some portions of some gas delivery lines. The inventors have discovered that the relatively high conductance of the high conductance line sections advantageously allows for relatively large amounts of gas to flow to reduce precursor or purge gas exposure times. By way of example only, in the example configuration shown in Figures 2B and 2C, the high conductance line sections 230, 234, and 238 for precursor delivery lines 210, 214, and 228, respectively, and the high conductance line sections 228-1 and 228-2 for RP purge gas delivery lines 218-1 and 218-3, respectively, may be cylindrical in shape, e.g., extending in the flow direction, with a diameter of 0.5 inches, 1 inch, 1.5 inches, 2.0 inches, 2.5 inches, 3.0 inches, 3.5 inches, 4.0 inches, 4.5 inches, 5 inches, or a value within a range defined by any of these values. The high conductance line portion additionally has a length that exceeds 5 inches, 10 inches, 20 inches, 50 inches, 100 inches, or a value within a range defined by any of these values. In such a configuration, relative to a low conductance line portion formed with a standard diameter, e.g., 0.25 inches or 0.5 inches, the conductance of the high conductance line portion can be greater than a value within a range defined by 4, 10, 20, 50, 100, 200, 500, 1000, 2000, 5000, 10,000, or more values, according to various embodiments.

[0054] The inventors have further found that in addition to high inductance for high flow rates, the high conductance line locations are advantageously configured to deliver sufficient amounts of precursor and purge gas such that repeated or relatively long exposures result in relatively little pressure fluctuation or drift. According to various embodiments, the high conductance line portions have volumes greater than 0.3 L, 0.5 L, 1.0 L, 1.5 L, 2.0 L, 2.5 L, 3.0 L, 3.5 L, 4.0 L, 4.5 L, 5.0 L, or values ​​within a range defined by any of these values. By way of example only, in the embodiment shown in Figures 2B and 2C, the high conductance line portions of the gas delivery lines for Prec.1 (e.g., TiCl4), Prec.2 (e.g., SiH2Cl2), Prec.3 (e.g., NH3), and RP (e.g., N2) have volumes of 3.4 L, 0.56 L, 0.56 L, and 0.4 L, respectively.

[0055] Advantageously, delivery lines including high conductance line sections as described herein are configured to deliver a high precursor dosage for a given pulse of precursor exposure. According to embodiments, the delivery lines are configured to flow gas at a flow rate greater than 50 sccm, 1000 sccm, 2000 sccm, 4000 sccm, 6000 sccm, 8000 sccm, 10,000 sccm, or a value within a range defined by any of these values. Advantageously, the relatively high dosage can reduce the exposure time or number of pulses, or both, to reach a particular substrate surface saturation level.

[0056] The inventors have appreciated that the physical shape and dimensions of the high conductance delivery lines as disclosed herein, as well as their positioning relative to their entry points into the deposition chamber, can be advantageously optimized to reduce residence time of the precursors. As shown in FIG. 2B, high conductance line portions 230, 234, and 238 for precursor delivery and high conductance line portions 228-1, 228-2 for purge gas delivery are disposed above lid portion 210 so as to overlap at least one of lids 112-1, 112-2, 112-3, 112-4. In addition, the length of the low conductance line section from the exit point from the high conductance line section to the respective ALD block for a given gas (including the section from the exit point to manifold 136 and the section from the manifold to the ALD valve block) is 30 inches, 25 inches, 20 inches, 15 inches, 10 inches, or a distance within a range defined by any of these values.

[0057] FIG. 3 is an experimental graph showing precursor volumes delivered to a process chamber using successive exposure pulses for different high conductance line sections with different volumes. Measurements were taken from a precursor delivery line similar to the first precursor delivery line 210 including the high conductance line section 230 as described above with respect to FIGS. 2B and 2C, using TiCl4 as an example. Measurements were taken by first filling the precursor delivery line including the high conductance line section, followed by applying multiple cycles of ALD deposition. Measurements were taken for delivery lines configured for flow rates of 1.6 standard liters per minute (SLM), 3.2 SLM, and 4.4 SLM. The experimental ALD cycle used to obtain the data is shown at the top and consisted of a 0.4 second TiCl4 pulse, a 0.05 second fast purge, a 0.2 second NH3 pulse, and a 0.05 second fast purge, performed in succession. For precursor delivery lines configured for different flow rates of 1.6 SLM, 3.2 SLM, and 4.4 SLM, the volume of gas delivered in each successive pulse decreases nonlinearly as the number of pulses increases. For precursor delivery lines configured for different flow rates of 1.6 SLM, 3.2 SLM, and 4.4 SLM, the observed volumes of precursor delivered by the first pulse were approximately 0.27 L, 0.55 L, and 0.76 L, respectively, for 0.4 second pulses. According to various embodiments, the volume of gas delivered every 0.4 seconds can have a value greater than 0.2 L, 0.4 L, 0.6 L, 0.8 L, 1.0 L, 1.2 L, 1.5 L, or within a range defined by any of these values.

[0058] 4A and 4B respectively show experimental measurements of pressure changes in a precursor delivery line with and without a high conductance line portion when an atomic layer deposition (ALD) valve is opened to introduce precursors into a thin film process chamber. The pressure changes were measured from a precursor delivery line similar to the first precursor delivery line 210 including the high conductance line portion 230 as described above with respect to FIGS. 2B and 2C, respectively, using a pressure monitoring sensor 230P as shown in FIG. 2B. The measurements were made by filling the precursor delivery line 210 with TiCl4 as an example precursor and opening the ALD valve connected thereto for 0.1 seconds. As shown, the presence of the high conductance line portion 230 advantageously significantly reduces the pressure drop in the precursor delivery line. As shown in FIG. 4A, without the high conductance line portion 230, the pressure drop inside the precursor delivery line can exceed 50 Torr or 70% (from 71 Torr to 17 Torr). In contrast, introducing precursors into a thin film deposition chamber by opening a valve, such as an ALD valve connected to a precursor delivery line 210 including a high conductance line portion 230 according to an embodiment, significantly reduces the pressure drop. As shown in FIG. 4B, the pressure drop inside the precursor delivery line does not exceed 3 Torr or 5%. As described below with respect to FIG. 8A, the inventors have shown that the pre-charge pressure can be important to obtain high step coverage values ​​of films deposited in vias or trenches.

[0059] 4A and 4B, the inventors have determined that one or more of the pressure within the high conductance line portion immediately prior to actuating the ALD valve, the pressure change within the high conductance line portion during exposure, the run-to-run standard deviation of the average pressure within the high conductance line portion, and the run-to-run pressure drift of the average pressure within the high conductance line portion may be important to certain film properties, such as step coverage. According to an embodiment, the pressure within the delivery line portion prior to opening the ALD valve to expose the substrate is maintained above 40 Torr, 50 Torr, 60 Torr, 70 Torr, 80 Torr, 100 Torr, 120 Torr, 140 Torr, 160 Torr, 180 Torr, 200 Torr, or a value within a range defined by any of these values. According to embodiments, due at least in part to the presence of the high conductance line portion, the pressure change or drop in the high conductance line portion upon opening of the valve, for example in less than 1 second, is less than 50 Torr, 40 Torr, 30 Torr, 20 Torr, 10 Torr, 5 Torr, 3 Torr, 1 Torr, or a value within a range defined by any of these values, or less than 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%, 2%, or a value within a range defined by any of these values. Further according to the embodiment, due to the presence, at least in part, of the high conductance line portion, the run-to-run standard deviation of the pressure change in the high conductance line portion is less than 5 Torr, 4 Torr, 3 Torr, 2 Torr, 1 Torr, 0.5 Torr, 0.3 Torr, 0.1 Torr, or a value within a range defined by any of these values, or less than 20%, 15%, 10%, 5%, 2%, 1%, or a value within a range defined by any of these values ​​of the average value.Further according to the embodiment, due at least in part to the presence of the high conductance line portion, the run-to-run drift of the average pressure in the high conductance line portion is less than 20 Torr, 15 Torr, 10 Torr, 8 Torr, 6 Torr, 4 Torr, 2 Torr, or a value within a range defined by any of these values, or 30%, 25%, 20%, 15%, 10%, 5% of the average, or a value within a range defined by any of these values. Further experimental validation of these parameters with respect to providing various process stability and improved film properties, including, but not limited to, step coverage for high aspect ratio openings and within-wafer thickness uniformity, is shown with respect to Figures 8A-8C.

[0060] Advantageously, the high conductance line section acting as an intermediate gas reservoir according to embodiments allows for various advantageous technical effects described herein, such as high flow rates and reduced exposure times for a process chamber including one or more processing stations, without excessively increasing the pressure within the precursor delivery line, thereby improving safety in accordance with industry standards. According to embodiments, the increased conductance line section is configured to maintain a pressure within the delivery line that is less than 650 Torr, 600 Torr, 550 Torr, 500 Torr, 450 Torr, 400 Torr, 350 Torr, 300 Torr, 250 Torr, 200 Torr, 150 Torr, 100 Torr, 50 Torr, or a value within a range defined by any of these values.

[0061] ALD valves for high-speed cyclic deposition systems Various combinations enabling high speed cyclic volume features as disclosed herein further include ALD valves as disclosed herein. Returning to FIG. 2B, thin film deposition chamber 200B is configured with delivery lines including high conductance line sections that deliver precursor and purge gases. After the high conductance line sections, each delivery line branches off from a respective common manifold 136 in a manner similar to that described above with respect to FIG. 1. Lid sections 112-1, 112-2, 112-3, and 112-4 are mounted on top of lid section 210 of deposition chamber 200B to deliver precursor and purge gases to respective processing stations. Lid sections 112-1, 112-2, 112-3, and 112-4 are disposed at central positions of respective ones of multi-valve blocks 250-1, 250-2, 250-4, and 250-4. Multi-valve blocks 250-1, 250-2, 250-3, and 250-4, in turn, can be fitted with multiple ALD valves, which can further enable high rate cyclic depositions. Exemplary configurations of these multi-valve blocks 250-1, 250-2, 250-3, and 250-4 are described herein.

[0062] 5A shows a perspective view of a multi-valve block assembly for a precursor delivery system configured with a precursor delivery line having a high conductance line portion, according to an embodiment. Multi-valve block assembly 250 can correspond to any one of multi-valve block assemblies 250-1, 250-2, 250-3, 250-4 (FIG. 2B), which in turn can correspond to multi-valve block assembly 150 shown generally in FIG. 1. Multi-valve block assembly 250 is split into two halves each including one of first and second multi-valve blocks 304-1, 304-2. Each of first and second multi-valve blocks 304-1, 304-2 has multiple ALD valves connected thereto. By way of example only, in the illustrated embodiment, the first multi-valve block 304-1 is configured to deliver a first precursor (Prec.1), e.g., TiCl4, through two first precursor ALD valves 140-1, 140-2 connected thereto, and a second precursor (Prec.2), e.g., SiCl2H2, through two second precursor ALD valves 144-1, 144-2 connected thereto. The first multi-valve block 304-1 is further configured to deliver a purge gas, e.g., N2 or Ar, through a first purge gas ALD valve 148-1 connected thereto. The second multi-valve block 304-2 is configured to deliver a third precursor (Prec.3), e.g., NH3, through four precursor ALD valves 220-1, 220-2, 220-3, 220-4 connected thereto. The second multi-valve block 304-2 is further configured to deliver a purge gas, such as N2 or Ar, through a second purge gas ALD valve 148-2 connected thereto. The multi-valve block assembly 250 thus configured includes two or more atomic layer deposition (ALD) valves configured to deliver the same precursors for the three precursors and a purge gas, according to an embodiment. The illustrated multi-block assembly 250 has ten ALD valves coupled thereto.However, embodiments are not so limited and the number of ALD valves may be greater or less than ten.

[0063] 5A, the multi-valve block assembly 250 is connected at its bottom to a central region of the top surface of the lid of the deposition chamber 102 (FIG. 1). The top surface of the lid is physically external to the deposition chamber 102. In this configuration, the multi-valve block assembly 250 is configured to position the ALD valves directly above the central region of the substrate inside the deposition chamber 102. The ALD valves for the precursors and purge gases are connected to the multi-valve block assembly 250 disposed outside the thin film deposition chamber 102, and the multi-block assembly 250 is configured to act as a hub for receiving and introducing the precursors and purge gases through the respective ALD valves into the thin film deposition chamber 100 (FIG. 2B). Inside the process chamber, a nozzle 108 (FIG. 1) is mounted on the lid, which in turn is connected to a gas distribution plate 112 (FIG. 1), also called a showerhead, configured to diffuse the precursors over the substrate 120 (FIG. 1) on the susceptor 116 (FIG. 1).

[0064] FIG. 5B illustrates a perspective view of one of the multi-valve blocks shown in FIG. 5A configured to couple multiple ALD valves connected in parallel to a common gas distribution plate, according to an embodiment. The multi-valve block may be a solid block with conduits or channels formed therein that is disposed external to thin film deposition chamber 102 (FIGS. 1, 2B) and serves as a hub to receive a first of the precursors and direct the precursor and purge gases through internal conduits or channels defined therein. In particular, FIG. 5B illustrates a perspective view of the first multi-valve block 304-1 shown in FIG. 5A. For clarity, the first multi-valve block 304-1 is shown without any ALD valves attached. Instead, mounting positions are indicated by dashed circles for two first precursor ALD valves 140-1, 140-2 configured to deliver a first precursor (Proc.1), e.g., TiCl4, two second precursor ALD valves 144-1, 144-2 configured to deliver a second precursor (Prec.2), e.g., SiCl2H2, and a first purge gas ALD valve 148-1 configured to deliver an inert gas. The mounting positions of the two first precursor ALD valves 140-1, 140-2 and the two second precursor ALD valves 144-1, 144-2 each include an inlet (IN), an outlet (OUT), and an inert gas inlet (INERT). Unlike the precursor ALD valve, which is a three-port ALD valve as described above, the mounting position of the first purge-gas ALD valve 148-1, which is a two-port ALD valve as described above, includes an inlet (IN) and an outlet (OUT), but the inert gas inlet is omitted.

[0065] The first multi-valve block 304-1 includes multiple gas input ports 308, 312, 316, 320 for receiving precursor and purge gases. In the illustrated configuration, the input ports 308 and 312 are configured to supply a first precursor (Prec. 1), e.g., TiCl4, and a second precursor (Prec. 2), e.g., SiCl2H2, similar to the configuration shown in FIG. 5A. In addition, the input ports 316, 320 are configured to supply a purge gas, e.g., N2 or Ar, for delivery as a fast purge (RP) gas and a continuous purge (CP) gas, respectively. Although not shown, the second multi-valve block 304-2 may be similarly configured, except that a third precursor (Prec. 3) supplies into the two precursor input ports 308 and 312. Of course, the input ports are not limited to the illustrated configuration, and there may be additional or fewer input ports depending on the number of gases and the number of delivery lines / ALD valves desired for each gas.

[0066] 5B, upon entering through input ports 308, 312, 316, 320, the respective precursor and purge gases are directed through respective conduits before being introduced into the respective ALD valves. The precursors enter respective ones of the ALD valves 140-1, 140-2, 144-1, 144-2 through respective inlets. The CP gas enters each of the precursor ALD valves 140-1, 140-2, 144-1, 144-2 through respective purge gas inlets (INERT). Each of the precursor and CP gases exits through a respective outlet (OUT) and travels through a respective outlet conduit 328 before being introduced into the vertically extending central conduit 324 and then exits the first multi-valve block 304-1 through the central outlet 332 and enters the deposition chamber 102 (FIGS. 1 and 2B), for example, through the nozzle 108 (FIG. 1) and the gas distribution plate 112 (FIG. 1).

[0067] The central conduit 324 may be disposed above a central region of the substrate 120 (FIG. 1) and configured to consolidate precursor and purge gases from multiple ALD valves and then introduce them into the deposition chamber, for example through the nozzle 108 (FIG. 1), before being distributed by the gas distribution plate 112 (FIG. 1). Thus, in the illustrated configuration, the central conduit 324 is the final conduit for the precursor and purge gases before they are introduced into the deposition chamber 102. The inventors have found that the configuration of the multi-valve block assembly 250 (FIG. 5A), including the centrally disposed position and arrangement of the conduits, can be important to realize various advantages, including fast precursor delivery times. For example, the inventors have found that the vertical position of the ALD valves disposed vertically above the surface of the substrate 120 (FIG. 1) can be important to achieve substantial saturation of the substrate surface with each precursor in exposure times of less than 1 second. As described herein, substantial saturation refers to a condition in which increasing the exposure time does not substantially increase the growth rate. For example, for various materials, increasing the exposure time by 20%, 50%, 100%, or a value within a range defined by any of these values, does not increase the growth rate by more than 1%, 2%, 5%, 10%, or a value within a range defined by any of these values.

[0068] In particular, and with further reference to FIG. 5B , among various design parameters, the inventors have discovered that the vertical position of the outlets (OUT) of the precursor and purge gas ALD valves, which defines the distance from the ALD valve to the central outlet 332, and the diameter of the central conduit 324, which in combination define the conductance of the central conduit 324, can be important in reducing the residence time of the precursors from the ALD valve to the substrate. To reduce the precursor residence time, according to various embodiments, the vertical position of the outlets (OUT) of the precursor and purge gas ALD valves relative to the central outlet 332, which defines the lower end of the central conduit 324, the maximum of which is defined by the length of the central conduit 324, is less than 5 inches, 4 inches, 3 inches, 2 inches, 1 inch, or has a value within a range defined by any of these values. In addition, the central conduit 324 has a diameter greater than 0.2 inches, 0.30 inches, 0.40 inches, 0.50 inches, 0.60 inches, or a value within a range defined by any of these values. In the illustrated example, the length of the central conduit 324 is about 3.7 inches, and the outlets of each of the precursor ALD valves 140-1, 140-2, 144-1, and 144-2 are disposed within about 2.0 inches of the central outlet 332. The OUT of the first purge ALD valve 148-1 for introducing a rapid purge (RP) is disposed above the precursor ALD valves 140-1, 140-2, 144-1, and 144-2, so that the OUT of the first purge ALD valve 148-1 is disposed further away, within about 4 inches of the central outlet 332. In addition, the central conduit 324 has a diameter of 0.375 inches.

[0069] The inventors have further discovered that the length of the outlet conduit 328, which defines the conductance from the outlet (OUT) of the ALD valve to the central conduit 324, and the diameter of the outlet conduit 328, which in combination defines the conductance of the outlet conduit 328, can also be important in reducing the residence time of the precursor from the ALD valve to the substrate. To reduce the precursor residence time, according to various embodiments, the outlet conduit 328 can be designed to have a value of 2 inches, 1.5 inches, 1 inch, 0.5 inches, or within a range defined by any of these values. In addition, the outlet conduit 328 has a diameter greater than 0.10 inches, 0.20 inches, 0.30 inches, 0.40 inches, or within a range defined by any of these values. In the illustrated example, the length and diameter of the outlet conduit 328 are 0.86 inches and 0.216 inches, respectively.

[0070] 5B, the inventors have further discovered that the number of bends in the length of the conduit between the input ports 308, 312, 316, 320 and the central outlet 332 can be kept low to improve the conductance throughout the conduit, thereby improving the conductance of the substrate and the gas delivery time to the substrate. According to various embodiments, the number of bends is three, two, or one or less. In the illustrated example, the number of bends in each of the lengths of the conduit between the input ports 308, 312, 316, 320 and the central outlet 332 is four or less, with two or three bends between the input ports 308, 312, 316, 320 and the IN of each of the ALD valves 140-1, 140-2, 144-1, 144-2, 148-1, and one bend between each of the OUT of the ALD valves and the central outlet 332.

[0071] Moreover, the inventors have further discovered that it is advantageous to closely align the central vertical axis, central conduit 324, and / or central outlet 332 (FIG. 5B) of multi-valve block 250 with a central location of the deposition chamber lid and / or substrate to minimize gas residence time and / or gas delivery time to the substrate. According to various embodiments, the lateral offset of the central vertical axis, central conduit 324, and / or central outlet 332 (FIG. 5B) of multi-valve block 250 and the central location of the deposition chamber lid and / or substrate is equal to or less than 2 inches, 1 inch, 0.5 inches, 0.25 inches, or has a value within a range defined by any of these values.

[0072] 5B, multiple ALD valves configured to deliver the same gas (precursor or purge gas) configured in this manner can be commonly connected upstream to a common one of the input ports 308, 312, 316, 320. After branching into individual inlet conduits and feeding into the respective ALD valves, each gas is delivered into the deposition chamber 102 (FIGS. 1, 2B) through a common central conduit 324. Two or more ALD valves connected to the first multi-valve block 304-1 configured in this manner are advantageously configured to simultaneously or sequentially feed the same gas into the deposition chamber.

[0073] FIG. 5C shows a perspective view of one of the ALD valves configured to couple to the multi-valve block shown in FIG. 5B, according to an embodiment. The illustrated ALD valve 350 can represent one of the first precursor ALD valves 140-1, 140-2, the second precursor ALD valves 144-1, 144-2, and the purge gas ALD valve 148-1 described above with respect to FIGS. 5A and 5B, according to an embodiment. The illustrated ALD valve 350 is divided into an upper portion 354 and a lower portion 358 coupled to a multi-valve block, such as that shown in FIG. 5B. The upper portion 354 and the lower portion 358 are connected by a coupling portion 362 that pneumatically couples the upper portion 354 and the lower portion 358. The illustrated ALD valve 350 additionally includes a thermocouple unit 366 for temperature sensing and / or control. The upper portion 354 includes a pneumatic actuator assembly that includes a solenoid pilot valve, among various other components. The lower portion 358 includes a valve body portion, including a valve body, a valve diaphragm, and a valve seat, among various other components. The position of the valve diaphragm can be monitored by a position sensor. In this configuration, the ALD valve 350 can be configured as a pilot operated diaphragm solenoid valve. As described herein, a pilot operated solenoid valve refers to a solenoid valve that uses a differential pressure of a medium above a valve port to open and close the valve. A pilot operated diaphragm solenoid valve uses a small chamber directly above the diaphragm to assist in the operation of the valve. Process fluid is allowed to enter the chamber through a small orifice in the inlet port, which in a normally closed valve compresses the diaphragm and forces it against the seat to maintain a closed seal. When current is applied to the pilot solenoid, the diaphragm is pulled upward against the spring pressure, forcing the pilot fluid in the chamber back through the orifice in the inlet port to rejoin the main flow through the valve body at the inlet port. Pilot operated diaphragm solenoid valves are capable of fast operation (response times less than 30 milliseconds).In addition, pilot operated diaphragm solenoid valves can provide relatively high flow rates and can operate over higher pressure and temperature ranges and consume less power compared to direct actuated solenoid valves.

[0074] FIG. 5D is an example experimental chart showing various signals associated with the actuation of an ALD valve such as that shown in FIG. 5C, according to an embodiment. The experimental chart shows, by way of example, curve 370-1 corresponding to a command signal sent electronically from a valve controller to the ALD valve, curve 370-2 corresponding to an electrical profile of a solenoid pilot valve, curve 370-3 corresponding to a diaphragm position, and curve 370-4 corresponding to an electronic position sensor signal. In operation, when a command signal is given by the valve controller, as shown in curve 370-1, the pilot valve is actuated, as shown in curve 370-2. When the solenoid pilot valve is fully open, the diaphragm changes its position and the valve opens, as shown in curve 370-3. As shown in FIG. 5D, the duration between the opening of the valve and the opening of the pilot valve, as verified by the sensor, defines the actuation speed. After the valve is fully open, the position sensor senses the position of the diaphragm and determines that the valve has completed its opening. As defined herein, the response time of an ALD valve corresponds to the time it takes from when a command signal is electronically sent from the valve controller to the ALD valve to when the ALD valve is fully opened or closed, as sensed by a diaphragm position sensor, as shown in Figure 5D. For the ALD valve shown, the actuation speed is less than 5 ms and the response time is less than 15 ms.

[0075] As discussed above, the precursor delivery systems disclosed herein allow for much greater precursor flow rates through high conductance lines and ALD valves than conventional thin film deposition systems, thereby significantly reducing ALD cycle times. In addition, the inventors have discovered that various other improvements disclosed herein can reduce the duration of an ALD cycle.

[0076] The inventors have discovered that reducing the distance between the outlet (OUT) of the ALD valve and the substrate (valve-substrate distance) can be advantageous and important to further reduce the time required for sufficient substantial surface saturation and / or ALD cycle time. Thus, according to embodiments, an ALD valve according to embodiments is disposed directly above the lid portion of each processing station, which is then disposed above the corresponding susceptor. The ALD valve is disposed, for example, within a distance of 30 inches, 25 inches, 20 inches, 15 inches, 10 inches, 5 inches, 3 inches, or within a range defined by any of these values, or within a distance of 50 cm, 40 cm, 30 cm, 20 cm, 10 cm, 5 cm, or within a range defined by any of these values, relative to a major surface of the substrate (FIG. 1). The valve-to-substrate distance can be the sum of the vertical distance between the outlet (OUT) of the precursor ALD valve and the central outlet 332 (FIG. 5B) that defines the lower end of the central conduit 324 (FIG. 5B), and the vertical distance from the central outlet 332 to the substrate surface.

[0077] The inventors have found that the placement of the tubing between the actuator of the ALD valve and the solenoid of the pilot valve can further affect the ALD valve response time. In particular, the inventors have found that reducing the length of the tubing advantageously reduces the valve response time. The inventors have found that the response time can be further reduced by reducing the length of the tubing, which may be 1 / 8 inch or 1 / 4 inch in diameter, between the actuator assembly of the ALD valve at the top 354 (FIG. 5C) and the valve body at the bottom 358 (FIG. 5C), and more particularly, the distance between the solenoid in the actuator assembly and the diaphragm of the body, for example. According to an embodiment, this distance has a value of less than 5 inches, 4 inches, 3 inches, 2 inches, 1 inch, 0.5 inches, or within a range defined by any of these values, or is 10 cm, 8 cm, 6 cm, 4 cm, 2 cm, 1 cm, or within a range defined by any of these values. For example, it has been found that reducing the length from 36 inches to 3 inches can reduce the response time by up to 10 ms.

[0078] Configured in this manner, ALD valves according to embodiments are configured to operate with significantly improved actuation speeds and response times as compared to conventional valves in ALD systems. According to various embodiments, the actuation speed of an ALD valve can be reduced to less than 10 ms, 5 ms, 4 ms, 3 ms, 2 ms, or a value within a range defined by any of these values, and the response time can be reduced to less than 30 ms, 25 ms, 20 ms, 15 ms, 10 ms, 5 ms, or a value within a range defined by any of these values. These values ​​can be achieved, for example, at an actuation pressure of 50-90 psig.

[0079] The inventors have also found that the valve coefficient should be optimized to increase flow rate for a given pressure drop to improve response time. According to various embodiments, the ALD valve has a valve flow coefficient (C) that exceeds 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, or a value within a range defined by any of these values. v ).

[0080] In some circumstances, ALD valves according to embodiments are advantageously configured to operate at elevated temperatures. For example, when it is desirable to introduce a precursor, e.g., a vaporized liquid precursor, into a deposition chamber at elevated temperatures, it may be advantageous to heat the corresponding ALD valve and / or multi-valve block to a temperature above room temperature, e.g., to match the precursor temperature at the point of introduction into the multi-valve block. According to various embodiments, ALD valves are configured to operate at valve temperatures exceeding 80° C., 100° C., 150° C., 200° C., 250° C., or a temperature within a range defined by any of these values. In particular, returning to FIG. 5C, lower portion 358 may include a heater that heats the valve body portion. In these embodiments, coupling portion 362 may include an insulating housing portion that reduces the heating effect on upper portion 354, since heating may have adverse effects on the operation of the actuator assembly, e.g., reducing the repeatability of the actuation speed.

[0081] According to various embodiments, each ALD valve may be configured to perform more than 2, 5, 10, 20, 50, 100,000,000 open / close cycles before replacement or repair, or a value within a range defined by any of these values. When a single ALD valve is used for a given precursor, preventive maintenance may be performed after such a number of cycles. Advantageously, when two or more valves are used alternately to introduce a given precursor, the life of the ALD valve on a per-wafer processing basis may be increased proportionately. It will be appreciated that increasing the duration between preventive maintenance or chamber openings can significantly increase productivity and reduce production costs.

[0082] Conformal TiN-Based Thin Film Deposition with High Step Coverage Using High Rate Cyclic Deposition By providing a precursor delivery line as disclosed herein with a high conductance line portion that acts as an intermediate precursor reservoir, the precursor delivery system according to embodiments advantageously improves the rate and stability of precursors delivered to the process chamber. The increased precursor usage and stability advantageously enables various advantageous methods of depositing thin films. According to various embodiments, the method of depositing thin films includes alternatingly exposing a substrate in a thin film deposition chamber to multiple precursors. Exposing the substrate includes introducing one of the precursors into the thin film deposition chamber through precursor delivery lines each configured to deliver one of the precursors. Alternatingly exposing the substrate includes pressurizing the high conductance line portion to a first pressure with a first one of the precursors while a final valve, e.g., an ALD valve, is closed. The final valve is then opened for a duration, which causes a pressure drop in the high conductance line portion, but the drop is relatively small compared to conventional systems. For example, the pressure in the high conductance line portion remains above a second pressure that is less than 10% lower than the first pressure or any other value described above with respect to Figure 4B. As described above, in practicing the method, the inventors have determined that one or more of the pressure within the high conductance line portion immediately prior to actuating the ALD valve, the pressure change within the high conductance line portion during exposure, the run-to-run standard deviation of the average pressure within the high conductance line portion, and the run-to-run pressure drift of the average pressure within the high conductance line portion may be important to certain film properties, such as step coverage.

[0083] FIG. 6 illustrates, by way of example only, an example precursor delivery sequence for delivering one or more precursors using a precursor delivery system according to some embodiments. The first and second precursor inlets are connected to the first and second precursor delivery lines, including high conductance line portions arranged as described above. The ALD cycle includes a first subcycle exposing the substrate to the first precursor and a second subcycle exposing the substrate to the second precursor. As described above, the precursor ALD valves are each three-port valves, and in some implementations, a continuous purge (CP) gas, e.g., an inert gas, may be flowed through the ALD valve while the substrate is exposed to the first and / or second precursor. In the illustrated embodiment, the first and second subcycles each further include a rapid purge (RP) with an inert gas followed by exposure to one or both of the first and second precursors, respectively. The rapid purge may be performed using a purge ALD valve as described above. The rapid purge is greater than the continuous purge.

[0084] Advantageously, one or both of the first and second precursors may be introduced into the thin film deposition chamber through respective precursor delivery lines including an increased conductance line portion and an ALD valve as described above. Advantageously, the exposure time to reach the saturation level may be substantially reduced for one or both of the first and second precursors. For example, according to some embodiments, the exposure time may be reduced by more than 20%, 40%, 60%, 80%, or a value within a range defined by any of these values, for a given precursor, relative to the exposure time to reach the saturation level using a conventional gas delivery line. The surface saturation level may be inferred, for example, based on the deposition rate. That is, substantially the same thickness may be achieved while reducing the exposure time to the precursor by more than 20%, 40%, 50%, 60%, 80%, or a value within a range defined by any of these values, relative to an ALD process using a conventional precursor delivery line for a given precursor.

[0085] According to an embodiment, the exposure time of one or both of the first and second precursors can be less than 1.0 seconds, 0.8 seconds, 0.6 seconds, 0.4 seconds, 0.2 seconds, 0.1 seconds, 0.05 seconds, 0.01 seconds, or a value within a range defined by any of these values. The thin film deposition system is configured to introduce one or both of the first and second precursors through the precursor delivery line according to an embodiment at a flow rate such that the surface of the substrate substantially reaches a saturation level within the exposure time, for example, a saturation level greater than 40%, 60%, 80%, or a range within a range defined by any of these values. In an embodiment where the exposure to the precursor is followed by a rapid purge, the duration of one or both of the first and second sub-cycles can be less than 1.0 seconds, 0.8 seconds, 0.6 seconds, 0.4 seconds, 0.2 seconds, 0.1 seconds, 0.05 seconds, 0.01 seconds, or a value within a range defined by any of these values. By reducing the exposure time of one or both of the first and second precursors, the duration of one or both of the corresponding first and second subcycles may be reduced, thereby reducing the overall ALD cycle time. According to embodiments, the duration of the overall ALD cycle is less than 2.0 seconds, 1.5 seconds, 1.0 seconds, 0.85 seconds, 0.5 seconds, or a value within a range defined by any of these values.

[0086] FIG. 6 illustrates, by way of example only, one particular example precursor delivery sequence using TiCl4 and NH3 to deliver precursors for cyclic deposition or ALD of TiN. The upper exposure cycle illustrated can correspond to an exposure cycle that can be achieved using the high conductance line segments and ALD valves described herein and can represent a TiCl4 exposure cycle through the first precursor ALD valves 140-1, 140-2 (FIG. 5A). Similarly, the lower exposure cycle illustrated can correspond to an NH3 exposure cycle through the second precursor ALD valves 144-1, 144-2 (FIG. 5A). Process stations similar to those described above with respect to FIG. 1 or FIG. 2B can be employed. For example, the process station may be configured to deliver TiCl4 through two first precursor ALD valves 140-1, 140-2 (FIG. 5A) and NH3 through four second precursor ALD valves 220-1, 220-2, 220-3, 220-4 (FIG. 5A). Also, each of the precursor ALD valves 140-1, 140-2, 220-1, 220-2, 220-3, 220-4 (FIG. 5A) is configured to continuously flow a continuous purge (CP) gas, e.g., an inert gas. The process station may also be configured to deliver a rapid purge (RP) gas, e.g., an inert gas, through two purge gas ALD valves 148-1, 148-2. The illustrated table shows typical parameters for a given process station and the flow conditions for the different ALD valves. In this example, flow rates of 220 sccm and 8000 sccm for TiCl4 and NH3, respectively, can be achieved by simultaneously delivering TiCl4 through two precursor ALD valves 140-1, 140-2, NH3 through four precursor ALD valves 220-1, 220-2, 220-3, 220-4, and N2 through one of two purge gas ALD valves 148-1, 148-2 during each sub-cycle.Combined with a flow rate of 5,000 sccm for purge gas ALD valves 148-1, 148-2, respectively, a TiCl4 exposure sub-cycle time of 0.5 s, and an NH3 exposure sub-cycle time of 0.35 s can be achieved for a total ALD cycle time of 1.05 s.

[0087] Advantageously, by flowing a relatively large amount of precursor and CP gases through two or more precursor ALD valves, a relatively high chamber pressure can be achieved without reducing the pumping power of the deposition chamber. The inventors have discovered that when a substrate has a relatively large surface area, for example, derived from a relatively high areal density of high aspect ratio structures, coating an exposed surface with a thin film using an ALD process recipe developed based on characterization of thin films formed on planar or unpatterned substrates, or substrates having a relatively small surface area or low areal density of high aspect ratio structures, can result in a thin film having different properties at different portions of the exposed surface. For example, conformality or step coverage, as discussed above, can be significantly worse for high aspect ratio structures on substrates with a relatively high areal density. Other properties that can also differ at different portions of the exposed surface include film stoichiometry, surface roughness, electrical resistivity, and film density, to name a few. Without being bound by any theory, one reason for the lower uniformity of properties can be the significantly increased exposed surface area of ​​the substrate relative to planar substrates. Due to the increased exposed surface area, different portions of the exposed surface may receive fluxes of precursors of different magnitudes, which may result in different amounts of precursor being adsorbed on different portions of the exposed surface. As just a simple example, a 300 mm semiconductor substrate may receive fluxes of precursors of 1×10 10For example, when a thin film is formed on hundreds of dies each having 10-100 nm diameters and 1-100 aspect ratios, the surface area exposed to the precursor during deposition of the thin film can exceed the surface area of ​​the corresponding unpatterned substrate by 10, 100, 1000 or more. In addition, the local deposition conditions at different portions of the exposed surface can be different. For example, the local pressure inside a deep trench or via can be different, e.g., lower, compared to areas outside the deep trench or via. In addition, under vacuum conditions, the gas molecules collide more with the sidewalls of the trench or via, so that the upper portion of the deep trench or via can adsorb a larger amount of precursor molecules so that it is not exposed to a larger flux.

[0088] According to various embodiments described herein, and particularly by utilizing higher deposition pressures, the inventors have discovered that the deposition methods described herein are particularly advantageous for forming thin films comprising TiN, TiSiN, and / or TiAlN on different portions of an exposed surface with greater uniformity with respect to various physical properties, including conformality, step coverage, film stoichiometry, surface roughness, electrical resistivity, and film density, to name a few.Thus, thin films comprising TiN, TiSiN, and / or TiAlN formed according to the deposition methods disclosed herein have greater uniformity with respect to one or more of these physical properties, both at a local (e.g., within a trench or via) and global (e.g., within a wafer) level. Thus, deposition methods according to embodiments are particularly advantageous for forming thin films comprising TiN, TiSiN, and / or TiAlN on substrates having a surface topography whereby the ratio of the surface area of ​​the semiconductor substrate exposed to one or more deposition cycles to the surface area of ​​the corresponding unpatterned semiconductor substrate is greater than 2, 5, 10, 20, 50, 100, 200, 500, 1000, or within a range or greater defined by any of these values.

[0089] Alternatively or in addition, deposition methods according to embodiments are further particularly advantageous for forming thin films on substrates with high aspect ratio structures having aperture widths of less than 1 micron, 500 nm, 200 nm, 100 nm, 50 nm, 20 nm, or values ​​within a range defined by any of these values, aspect ratios of more than 5, 10, 20, 50, 100, 200, or values ​​within a range defined by any of these values, and an areal density such that the surface area is greater than a planar substrate as described above. Substrates having such topographies may be conformally coated with thin films comprising TiN, TiSiN, and / or TiAlN according to embodiments with step coverages as described above having greater than 50%, 60%, 70%, 80%, 90%, 95%, or values ​​within a range defined by any of these values ​​or greater. As described above, the inventors have found that process conditions for conformally coating substrates having a relatively high areal density of high aspect ratio structures may be optimized according to embodiments to achieve these results. The inventors have discovered that these results may be achieved by controlling, among other things, the reaction chamber pressure or partial pressure of the precursor during exposure of the substrate, the deposition rate, the temperature or pressure of the precursor introduced into the reaction chamber, the flow rate of the precursor, and the exposure time, to name a few.

[0090] The inventors have discovered that, according to embodiments, when coating substrates having a relatively high areal density of high aspect ratio structures, a relatively high total or partial pressure achieved by simultaneously operating two or more precursor ALD valves can lead to improved conformality and step coverage. Without being bound by any theory, such improvement may be associated with, among other things, lessening the impact of locally reduced partial pressure of precursors inside high aspect ratio vias or trenches. According to embodiments, the total or partial pressure of any of the individual precursors (e.g., Ti precursor, N precursor, and / or Si and / or Al) during exposure of the substrate during a given subcycle may be 1.0-3.0 Torr, 3.0-5.0 Torr, 5.0-7.0 Torr, 7.0-9.0 Torr, 9.0-11.0 Torr, 11.0-13.0 Torr, 13.0-15.0 Torr, or a pressure within a range defined by any of these values. In each of the exposures to the Ti precursor, N precursor, and / or Si and / or Al precursor, each precursor can comprise 1-2%, 2-5%, 5-10%, 10-20%, 20-50%, 50-100%, or a percentage within a range defined by any of these values ​​of the total amount of gas molecules in the reaction chamber. The inventors have found that under some circumstances, step coverage may begin to degrade, among other things, when the total or partial pressure is outside of these values. An exemplary high step coverage observed in experiments is shown in FIG. 8B.

[0091] The inventors have discovered that, in part, to allow for a relatively high throughput while delivering a relatively large amount of precursor to the reaction chamber for deposition at a relatively high total or partial pressure, the flow rate of the precursor into the reaction chamber should be significantly higher than that used in process conditions for forming thin films on planar substrates and / or substrates with low (e.g., <1) aspect ratio structures. The high flow rate may then be achieved by increasing one or both of the temperature or pressure of the precursor prior to introducing the precursor into the reaction chamber. For example, in the case of a precursor that is liquid under manufacturing conditions, the precursor bottle may be heated to a temperature above room temperature, e.g., 30-60°C, 60-80°C, 80-100°C, 100-120°C, 120-150°C, or within a range defined by any of these values, to increase the vapor generation rate. The lower and upper bottle temperatures within these ranges may each be determined, in part, based on the vapor pressure of the precursor and the decomposition temperature of the precursor. By way of example, TiCl4 may be heated to about 60-80°C. On the other hand, for precursors that are gaseous under manufacturing conditions, high flow rates may be achieved by increasing the gas line pressure to increase the delivery pressure to a value much higher than the gas line pressure used to form thin films on relatively small surface area or planar substrates and / or substrates with low (e.g., <1) aspect ratio structures. It will be appreciated that the relatively high flow rates that achieve the various advantages described herein may depend on, among other things, pumping speed, exposure time, and reactor volume. To achieve flow rates adapted to deposit thin films on substrates having large surface areas and / or high aspect ratio structures, the temperature and / or pressure of the precursors, among other parameters, can be adjusted such that the flow rates of each of the Ti, N, Si, and Al precursors can be, for example, 100-1000 standard cubic centimeters per minute (sccm), 1000-2000 sccm, 2000-5000 sccm, 5000-10,000 sccm, 10,000-15,000 sccm, 15,000-20,000 sccm, or greater, or values ​​within a range defined by any of these values.It will be appreciated that suitable flow rates may depend, among other things, on the volume of the reactor, and some of these flow rates may be appropriate for a single wafer reactor having a volume of about 1-2 liters.

[0092] Tables 1A and 1B, by way of example only, show overall ALD cycle improvements for an example process sequence for depositing TiN films. Table 1A shows a recipe sequence implemented in a thin film deposition system such as that described above with respect to FIG. 2A, and Table 1B shows a recipe sequence implemented in a thin film deposition system including high conductance line portions and ALD valves such as that described above with respect to FIG. 2B, including gas delivery lines having high conductance line portions for TiCl4, NH3, and Ar, respectively. The two recipe sequences achieve similar usage per cycle and thickness per cycle with comparable step coverage. As shown, the ALD cycle for the recipe sequence shown in Table 1A lasts about 4.3 seconds, whereas the ALD cycle for the recipe sequence in Table 1B lasts about 0.85 seconds, representing more than a quarter-fold reduction in total cycle time. Additionally, the durations of the TiCl4 pulse, TiCl4 purge, NH4 pulse, and NH4 purge were reduced by approximately 4, 10, 3, and 7 times, respectively. [Table 1A] [Table 1B]

[0093] As described above, the precursor delivery system according to embodiments provides a high conductance line section configured according to embodiments in conjunction with an ALD valve that acts as an intermediate gas reservoir, thereby reducing pressure fluctuations in the gas delivery lines and allowing increased usage. This configuration can be particularly advantageous for process chambers having multiple process stations. In addition to throughput, the increased usage and stability of precursors delivered by this configuration advantageously translates into increased step coverage of thin films deposited in high aspect ratio structures.

[0094] One measure of conformality for high aspect ratio structures is referred to herein as step coverage. The high aspect ratio structures may be, for example, vias, holes, trenches, cavities, or similar structures. By way of illustration, FIG. 7 shows a schematic of a semiconductor structure 500 having an example high aspect ratio structure 516 formed thereon to illustrate some example metrics for defining and / or measuring conformality of thin films formed on the high aspect ratio structures. The illustrated high aspect ratio structure 516 is backed with a thin film 512 having different thicknesses in different portions, for example, a TiN layer deposited according to an embodiment. As described herein, the high aspect ratio structure has an aspect ratio greater than 1, for example, a ratio defined as the depth or height (H) of the high aspect ratio structure 516 divided by its width (W) in the open area. In the illustrated example, the high aspect ratio structure 516 is a via formed through a dielectric layer 508, e.g., an inter-metal dielectric (ILD) layer, formed on a semiconductor substrate 504 such that a bottom surface of the high aspect ratio structure 516 exposes the underlying semiconductor 504. The thin film 512 can coat different surfaces of the high aspect ratio structure 516 at different thicknesses. As described herein, one metric for defining or measuring the conformality of a thin film formed at a high aspect ratio is called step coverage. Step coverage may be defined as the ratio of the thickness of the thin film at the bottom or bottom region of the high aspect ratio structure to the thickness of the thin film at the top or top region of the high aspect ratio structure. The top or top region may be a region of the high aspect ratio structure at a relatively shallow depth of H, e.g., 0-10% or 0-25%, as measured from the top of the opening. The lower or bottom region may be a region of the high aspect ratio structure at a relatively deep depth of H, e.g., 90-100% or 75-100%, as measured from the top of the opening. In some high aspect ratio structures, the step coverage may be defined or measured by the ratio of the thickness of the thin film 512A formed on the bottom surface of the high aspect ratio structure to the thin film 512C formed on the top or top sidewall surface. However, it will be appreciated that some high aspect ratio structures may not have a well-defined bottom surface, or a bottom surface with a small radius of curvature.In these structures, step coverage may be more consistently defined or measured by the ratio of the thickness of the thin film 512B formed on the lower or bottom sidewall surface of the high aspect ratio structure to the thickness of the thin film 512C formed on the upper or top sidewall surface.

[0095] Precursor delivery systems according to embodiments provide substantial improvement in step coverage in high aspect ratio structures, due at least in part to the relatively stable pressure inside the precursor delivery lines. By using gas delivery lines having high conductance line portions with ALD valves, high aspect ratio structures having aspect ratios greater than 1, 2, 5, 10, 20, 50, 100, 200, or values ​​within a range defined by any of these values, may be conformally coated with thin films, such as TiN films according to embodiments, having step coverage as defined herein, greater than 70%, 80%, 90%, 95%, or values ​​within a range defined by any of these values. The step coverage values ​​thus obtained represent an improvement over corresponding step coverage values ​​obtained using a comparable thin film deposition system having gas delivery lines without high conductance line portions, by 5%, 10%, 15%, 20%, or values ​​within a range defined by any of these values.

[0096] Table 2 shows, by way of example only, the step coverage improvement achieved using a gas delivery system including a high conductance line portion in the precursor delivery line coupled to the ALD valve. In Table 2, the first two columns show recipe sequences implemented in a thin film deposition system such as that described above with respect to FIG. 2A, and the third column shows recipe sequences implemented in a thin film deposition system such as that described above with respect to FIG. 2B, including precursor delivery lines with high conductance line portions for TiCl4, NH3, and Ar, respectively, as well as an ALD valve. The three recipe sequences achieve similar thicknesses. As shown by the directly comparable recipe sequences in columns 1 and 3, the ALD cycle of the recipe sequence implemented with the high conductance line portion in the precursor delivery line achieves a substantial improvement in step coverage (>14%). [Table 2]

[0097] FIG. 8A shows measured step coverage values ​​of TiN thin films deposited in high aspect ratio structures as a function of precharge pressure in the high conductance line portion of a precursor delivery line configured according to an embodiment, prior to opening the ALD valve according to an embodiment described above. The overall deposition conditions can be similar to those described above with respect to FIG. 6. As shown, increasing the pressure inside the high conductance line portion prior to opening the ALD valve improves the step coverage. Surprisingly, a dramatic improvement in step coverage was observed at high conductance line portion pressures above about 62 Torr.

[0098] FIG. 8B shows measured step coverage values ​​of TiN thin films deposited in high aspect ratio structures for various process conditions using a precursor delivery system including high conductance line segments and ALD valves configured according to an embodiment. Variables tested include the gap distance between the substrate and the gas distribution plate (showerhead) (G), NH3 exposure time (N), TiCl4 exposure time (T), and TiCl4 temperature (T). With the exception of sample HP-5, all of the samples tested exhibited average step coverage of about 80% or higher.

[0099] FIG. 8C illustrates pressure fluctuations in the high inductance line portion of the precursor delivery line during cyclic deposition of TiN, according to an embodiment. The traces correspond to separate runs with each peak representing an exposure. Each trace captures more than 20 TiCl4 exposures per second. As shown, for an average pressure of about 43 Torr during multiple cycles, the standard deviation was about 0.4 Torr, less than about 1%. The precursor delivery system, including the high conductance line portion and the ALD valve, allows for high pressure stability, which in turn improves step coverage of thin films deposited in high aspect ratio structures. Additionally, the drift in the average pressure is less than about 4 Torr.

[0100] Purpose Thin films comprising TiN or TiSiN formed using different exposure pressures according to various embodiments described herein can be used in a variety of applications, particularly where the substrate comprises relatively high aspect ratio structures and / or non-metallic surfaces that can benefit from various advantageous properties of TiN or TiSiN layers as disclosed herein. Exemplary applications include deposition in vias, holes, trenches, cavities, or similar structures having an aspect ratio, e.g., a ratio defined as depth divided by top width, that exceeds 1, 2, 5, 10, 20, 50, 100, 200, or a value within a range defined by any of these values.

[0101] By way of example, FIG. 7 shows a schematic of a diffusion barrier-related application for contact structures, such as source or drain contacts, formed on active semiconductor substrate regions, which may be heavily doped. A portion of a semiconductor device 500 is shown, which includes a substrate 504 on which a dielectric layer 508, e.g., an interlayer or intermetal dielectric (ILD) layer comprising a dielectric material such as an oxide or nitride, is formed. Vias or trenches may be formed through the dielectric layer 508 to form contacts to various regions of the substrate 504, including various doped regions, e.g., source and drain regions. The vias or trenches may expose various non-metallic surfaces, e.g., the exposed bottom surface including the substrate surface, e.g., the silicon substrate surface, as well as the dielectric sidewalls of the vias. The bottom and side surfaces of the vias may be conformally coated with a TiN or TiSiN layer. The lined vias may then be filled with a metal, e.g., W, Al, or Cu, to form contact plugs 516. For example, the vias may be filled with tungsten by CVD, e.g., using WF6.

[0102] The barrier layer 512 formed according to embodiments may be advantageous for a variety of reasons. In particular, the conformal nature of the barrier layer 512 formed by ALD may substantially reduce the tendency to pinch off during a subsequent metal filling process. In addition, as discussed above, the barrier layer 512 may effectively impede material transport throughout it, such as out-diffusion of dopants (B, P) from the substrate 504, as well as in-diffusion of reactants, etchants, and metals (e.g., F, Cl, W, or Cu) from the contact plug formation process. The barrier effect may be improved by reducing surface roughness and increasing step coverage. Furthermore, the layer-by-layer growth mode obtained according to embodiments may reduce the contact resistance across the barrier layer 512. Furthermore, the reduced film roughness may result in a relatively thinner barrier layer 512 while still performing the desired barrier function, which leads to further reduction in contact resistance.

[0103] Other applications of TiN or TiSiN layers formed according to various embodiments disclosed herein include conductive features (e.g., buried electrodes or lines) formed on concave substrates, electrodes (e.g., DRAM capacitor electrodes or gate electrodes), metallization barriers for upper metal levels (e.g., barriers in vias / trenches for Cu contacts / lines), high aspect ratio vertical rod electrodes or vias for 3D memory and through silicon vias (TSVs), to name a few.

[0104] While the invention has been described herein with reference to particular embodiments, these embodiments do not serve to limit the invention, but are set forth for purposes of illustration. It will be apparent to those skilled in the art that modifications and improvements can be made without departing from the spirit and scope of the invention.

[0105] Such simple modifications and improvements of the various embodiments disclosed herein are within the scope of the disclosed technology, the particular scope of the disclosed technology being further defined by the appended claims.

[0106] In the above, any feature of any one of the embodiments can be combined with or substituted for any other feature of any other one of the embodiments.

[0107] Unless otherwise clearly required by context, throughout the specification and claims, the words "comprise," "comprising," "include," "including," and the like, should be interpreted in an inclusive sense, i.e., "including but not limited to," rather than an exclusive or exhaustive sense. The term "coupled," as used generally herein, refers to two or more elements, which may be directly connected or connected using one or more intermediate elements. Similarly, the term "connected," as used generally herein, refers to two or more elements, which may be directly connected or connected using one or more intermediate elements. In addition, the words "herein," "above," "below," and words of similar import, as used herein, shall refer to this application as a whole and not to any particular portion of this application. Where the context permits, words in the above detailed description using the singular or plural may also each include the plural or singular. The word "or" when referring to a list of two or more items includes all interpretations of the word to any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0108] Additionally, conditional language used herein, such as, among others, "can," "could," "might," "may," "eg," "for example," and "such as," is generally intended to convey that certain embodiments include certain features, elements, and / or conditions, but not other embodiments, unless specifically specified otherwise or understood otherwise within the context in which it is used. Thus, such conditional language is generally intended to imply that the features, elements, and / or conditions are required in some way for one or more embodiments, or that these features, elements, and / or conditions should be included in or implemented in any particular embodiment.

[0109] Although specific embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms, and various omissions, substitutions, and changes may be made in the methods and systems described herein without departing from the spirit of the disclosure. For example, while features are presented in a given arrangement, alternative embodiments may implement similar functionality using different components and / or sensor topologies, and some features may be deleted, moved, added, divided, combined, and / or modified. Each of these features may be realized 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 realized independently of each other or may be combined in various ways. All possible combinations and subcombinations of features of the present disclosure are intended to be within the scope of the present disclosure.

Claims

1. providing a thin film deposition system comprising a high conductance line section as part of a precursor delivery line between a precursor source and a final valve external to the thin film deposition chamber; the high conductance line portion extends in a flow direction and has a conductance at least four times that of either of the adjacent low conductance line portions connected to opposite ends of the high conductance line portion; exposing a substrate in the thin film deposition chamber to a plurality of precursors in alternating cycles; alternatingly exposing the substrate includes pressurizing the high conductance line portion to a first pressure with a first one of the precursors with the final valve closed, and opening the final valve for a duration such that pressure in the high conductance line portion remains above a second pressure that is less than 10% lower than the first pressure. Thin film deposition method.

2. The method of claim 1 , wherein the duration is less than 1 second.

3. The method of claim 2 , wherein the first pressure is from 70 to 650 Torr.

4. 4. The method of claim 3, wherein the pressure drop between the first pressure and the second pressure is less than 50 Torr.

5. 5. The method of claim 4, wherein the standard deviation of the average pressure in the high conductance line portion over the multiple cycles is less than 10%.

6. 5. The method of claim 4, wherein the drift of the average pressure in the high conductance line portion over the multiple cycles is less than 10%.

7. The method of claim 1 , wherein the high conductance line portion has a cylindrical shape with a diameter of 0.5 to 5 inches.

8. The method of claim 2 , wherein the high conductance line portion further has a length such that the volume is between 0.3 and 5 liters.

9. 4. The method of claim 3, wherein the high conductance line portion serves as a temporary intermediate reservoir configured to store a gas or liquid precursor that is pre-vaporized before reaching the high conductance line portion.

10. The method of claim 3 , wherein at least a portion of the high conductance line portion is disposed directly above a lid of the thin film deposition chamber.

11. 4. The method of claim 3, wherein the final valve is an ALD valve disposed directly above a lid of the thin film deposition chamber.

12. 12. The method of claim 11, wherein the final valve is actuated such that the precursor flows continuously from the precursor source through the high conductance line portion to the thin film deposition chamber without interruption by actuation of another valve during exposure of the substrate to the precursor in the precursor source.

13. The thin film deposition chamber comprises a plurality of processing stations each configured to deposit a respective thin film by alternately exposing a respective substrate to a plurality of the same or different precursors, each of the processing stations comprising: A gas distribution plate; A susceptor; a lid for sealing the thin film deposition chamber; The method of claim 11 , comprising:

14. 14. The method of claim 13, wherein the high conductance line portion acts as an intermediate reservoir such that the precursor flows continuously from the precursor source through the high conductance line portion to the thin film deposition chamber during exposure of the substrate to a precursor in the precursor source.

15. The method of claim 14 , wherein the high conductance line portion acts as a dedicated reservoir for the precursor source.

16. 12. The method of claim 11, wherein the ALD valve has a response time of less than 30 ms between the end of a command signal and the completion of opening or closing of a diaphragm of the ALD valve.

17. The ALD valve has a valve flow coefficient (C ｖ 12. The method of claim 11 , wherein

18. 12. The method of claim 11 , wherein introducing the first one of the precursors into the thin film deposition chamber comprises continuously flowing an inert gas into the thin film deposition chamber through the ALD valve while introducing the first one of the precursors into the thin film deposition chamber.

19. The method of claim 1 , wherein the thin film comprises a TiN thin film or a TiSiN thin film.

20. 20. The method of claim 19, wherein the plurality of precursors comprises one or more of a Ti precursor, a Si precursor, and a N precursor.

21. 2. The method of claim 1 , wherein alternatingly exposing the substrate comprises pressurizing the high conductance line portion to a third pressure with a second one of the precursors with the final valve closed, and opening the final valve for a duration such that pressure in the high conductance line portion remains above a fourth pressure that is less than 10% lower than the third pressure.

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