Temperature controlled showerhead assembly for circulating vapor deposition

Abstract

The temperature controlled showerhead assembly is configured to deliver a plurality of gases into the circulating deposition chamber. The showerhead assembly includes a showerhead body having a cavity formed through the showerhead body and at a central region of the showerhead body, where the cavity is configured to diffuse or mix gas prior to introduction of the gas into the deposition chamber. The showerhead assembly additionally includes a cooling channel of a mesh structure configured to conduct heat away from the showerhead body. The showerhead assembly further includes a mesh-structured heating element configured to supply heat to the showerhead body, where the mesh-structured heating element is disposed closer to an upper surface of the showerhead body than the cooling channel.

Description

[0001] Incorporation by reference into any prior application

[0002] Any and all applications for which foreign or domestic priority claims are identified in the Application Data Sheet filed with the present application are incorporated by reference pursuant to 37 CPR 1.57.

[0003] This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 371,564, filed on August 16, 2022, and entitled “TEMPERATURE-CONTROLLED SHOWERHEAD ASSEMBLY FOR CYCLIC VAPORDEPOSITION,” the entire contents of which are expressly incorporated herein by reference. Technical Field

[0004] The disclosed technology relates generally to thin film deposition systems, and more particularly to showerhead assemblies for cyclic vapor deposition systems. Background Art

[0005] As semiconductor devices continue to scale in lateral dimensions, the vertical dimensions of semiconductor devices scale accordingly, including the thickness scaling of functional films such as electrodes and dielectrics. Semiconductor manufacturing involves various films deposited and patterned throughout the process flow. Various techniques, including wet deposition methods and dry deposition methods, can be used to form the films used in semiconductor manufacturing. Wet deposition methods include, for example, aerosol / spray deposition, sol-gel methods, and spin coating. Dry deposition methods include physical vapor-based techniques, such as physical vapor deposition (PVD) and evaporation. Dry deposition methods additionally include techniques based on precursors and / or chemical reactions, such as chemical vapor deposition (CVD) and cyclic deposition, such as atomic layer deposition (ALD). Summary of the invention

[0006] In one aspect, a temperature-controlled showerhead assembly configured to deliver multiple gases to a cyclic deposition chamber includes a showerhead body having a cavity formed through the showerhead body and at a central region of the showerhead body, wherein the cavity is configured to diffuse or mix the gases before introducing them into the deposition chamber. The showerhead assembly further includes a network of cooling channels, the network of cooling channels configured to conduct heat away from the showerhead body. The showerhead assembly also includes a network of heating elements, the network of heating elements configured to supply heat to the showerhead body, wherein the network of heating elements is disposed closer to an upper surface of the showerhead body relative to the cooling channels.

[0007] In another aspect, a temperature controlled showerhead assembly configured to deliver multiple gases to a circulating deposition chamber includes a showerhead body having a generally flat outer surface facing away from a base disposed below the showerhead body, and the showerhead body having an inner surface facing the base, the inner surface tapering so that the thickness of the showerhead body increases from a central region of the showerhead body toward an edge portion of the showerhead body. The showerhead assembly further includes a cavity formed through the showerhead body at the central region and configured to diffuse or mix the gases before introducing them into the deposition chamber. The showerhead assembly also includes a reticulated cooling channel and a reticulated heating element, the reticulated cooling channel and the reticulated heating element being formed at different vertical heights.

[0008] In another aspect, a temperature-controlled sprinkler assembly configured to deliver multiple gases to a circulating deposition chamber includes a sprinkler body, the sprinkler body including a cavity formed through the sprinkler body and at a central region of the sprinkler body, wherein the cavity is configured to diffuse or mix the gases before introducing them into the deposition chamber. The sprinkler assembly further includes a reticulated cooling channel formed above the sprinkler body and configured to conduct heat away from the sprinkler head. The sprinkler assembly also includes a reticulated heating element configured to supply heat to the sprinkler head. The sprinkler assembly also includes a thermal insulation membrane vertically disposed between the cooling channel and the reticulated heating element. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A thin film deposition system is schematically illustrated according to an embodiment and includes a deposition chamber configured to deliver multiple gases using a temperature controlled showerhead assembly.

[0010] Figure 2 A perspective view of a top exterior portion of a thin film deposition system including a plurality of processing stations, each configured for a temperature controlled showerhead assembly, is shown according to some embodiments.

[0011] Figure 3A A cross-sectional view of a temperature controlled sprinkler head assembly is shown in accordance with some embodiments.

[0012] Figure 3B A cross-sectional view of a temperature controlled sprinkler head assembly according to some other embodiments is shown.

[0013] Figure 4 yes Figure 3B A partial cross-sectional view of a sprinkler head assembly is shown in FIG. 1 , including an expanded view of the diffusion / mixing chamber.

[0014] Figure 5 Shows Figure 3B A perspective view of a sprinkler head body of a sprinkler head assembly is shown in FIG.

[0015] Figure 6 Shown is a view of a diffusion / mixing chamber according to an embodiment.

[0016] Figure 7 The results of a computational fluid dynamics analysis performed to show Figure 6 Diffusion and mixing effects in the diffusion / mixing chamber shown in .

[0017] Figure 8 yes Figure 3B A partial cross-sectional view of a showerhead assembly is shown in FIG. 1 , including an expanded view of an edge portion of a deposition chamber.

[0018] Fig. 9 An exploded view of a sprinkler head assembly according to some embodiments is shown.

[0019] Fig.10 Shows Figure 3B The surface of the sprinkler head body of the sprinkler head assembly shown in FIG. 1 facing the substrate shows the location where the temperature sensor is disposed.

[0020] Fig.11 A schematic cross-sectional view of a sprinkler head assembly is shown, illustrating a cooling channel, a heater, and an insulation layer disposed between the cooling channel and the heater.

[0021] Fig.12 Shown is a graph of experimental temperature measurements from a sprinkler head body, according to some embodiments.

[0022] Fig.13 An exemplary precursor delivery sequence is shown.

[0023] Fig.14 An exemplary partial cross-sectional view of a semiconductor structure is shown, illustrating high aspect ratio features and step coverage of a thin film. DETAILED DESCRIPTION

[0024] Cyclic deposition processes such as atomic layer deposition (ALD) processes can provide relatively conformal thin films with high uniformity and thickness accuracy on relatively high aspect ratio (e.g., 2:1) structures on a substrate (e.g., a wafer). For the context of this disclosure, uniformity means the consistency of the thin film within the same substrate (e.g., consistency of thickness, resistivity, step coverage). Although generally less conformal and less uniform than ALD, thin films deposited using continuous deposition processes such as chemical vapor deposition (CVD) can provide higher yields and lower costs. ALD and CVD can be used to deposit a variety of different films, including elemental metals, metal compounds (e.g., titanium nitride (TiN), tantalum nitride (TaN), etc.), semiconductors (e.g., silicon (Si), III-V, etc.), dielectrics (e.g., silicon dioxide (SiO2), aluminum nitride (AlN), hafnium oxide (HfO2), zirconium oxide (ZrO2), etc.), rare earth oxides, conductive oxides (e.g., iridium oxide (IrO2), etc.), ferroelectrics (e.g., lead titanate (PbTiO3), lanthanum nickel oxide (LaNiO3), etc.), superconductors (e.g., yttrium barium copper oxide (Yba2Cu3O 7-x ) and chalcogenides, germanium-antimony-tellurium (GeSbTe), etc.

[0025] Some cyclic deposition processes, such as atomic layer deposition (ALD), involve exposing a substrate alternately to multiple precursors to form a thin film. Different precursors may alternately at least partially penetrate the surface of the substrate and react with each other, thereby forming a thin film in a layer-by-layer manner. There are different types of ALD, including time-based ALD and space-based ALD. In time-based ALD, precursors are sequentially injected, one at a time, to react with active sites on the substrate surface. Exposure to continuous precursors may be separated by a purge step to prevent mixing and reaction of continuous precursors in the gas phase. Therefore, the reaction is surface-limited and self-terminating, resulting in uniform deposition. In addition, many ALD processes can allow high-quality materials to be deposited at temperatures substantially lower than CVD, even close to room temperature. ALD growth can occur within a specific temperature range, below which the precursor molecules may not be fully activated or desorption may be too slow, and above which the precursors may decompose at the surface or even before reaching the surface, and desorption may be too fast during the purge step. Therefore, temperature control of the deposition chamber is important for high-quality thin film deposition using the ALD process.

[0026] Due to the layer-by-layer growth capability, ALD can achieve precise control of thickness and composition, which in turn can achieve precise control of various properties, such as conductivity, conformality, uniformity, barrier properties, and mechanical strength. In particular, due to the thickness scaling that often accompanies feature size scaling in semiconductor devices, there is an increasing need to improve uniformity within the wafer, even for ALD, which is known to produce thin films with very high uniformity relative to other technologies. Although ALD films generally have excellent uniformity, there can be several reasons why uniformity can be degraded during deposition. For example, uniformity can be degraded due to overlapping precursor pulses, non-uniform precursor distribution caused by insufficient mixing and / or diffusion, thermal self-decomposition of precursors, and non-uniformity of substrate temperature, among others.

[0027] Uneven precursor distribution may be caused by limited diffusion or by mixing with a carrier gas, as mentioned above. For example, in an ALD reactor (e.g., a deposition chamber formed in a processing station), precursors are introduced into a deposition or reaction chamber from individual source delivery lines, and the lines may be brought together to a common feed line before the precursors are introduced into an atomic layer deposition (ALD) chamber (e.g., a deposition chamber for short). Without being bound by any theory, a carrier gas that can flow through all precursor delivery lines may sometimes cause the carrier gas from one precursor delivery line to act as a diffusion barrier for precursors flowing from different precursor delivery lines. Although each precursor will be properly mixed with the carrier gas in each source delivery line, the precursor may not be properly dispersed beyond the intersection of the common chamber feed line, which is typically located at a short distance from the substrate in the upstream direction.

[0028] To alleviate such concerns, some processing stations employ means for distributing precursor / reactant and purge gases within the chamber volume. One such means includes a showerhead that is employed to effectively distribute and mix gases including precursors. Design variations of this hardware can range from flat designs to tapered designs. Gas distribution can be provided in one of several ways, including (1) across the surface of the showerhead via multiple holes provided by one or more plenums, (2) from the center of the showerhead, or (3) from one end to the other (also known as cross flow).

[0029] To reduce the above-mentioned non-uniformity problems caused by inadequate mixing or diffusion of gases, some deposition chambers, such as chambers with flat showerheads and distributed holes, have a larger spacing between the showerhead and the substrate to enhance mixing and diffusion and reduce the impact effect of the gas on the substrate. However, the increased spacing between the showerhead and the substrate comes at the expense of longer ALD cycle times due to the increased volume used to fill the gas and purge. In time-based ALD, the longer time required to fill and purge the chamber may also worsen the non-uniformity caused by overlapping precursor pulses, because the precursor pulses may have longer leading and trailing edges. In spatial deposition chambers with flat showerheads, the spacing can be smaller, but leading and trailing edge effects are still generally possible.

[0030] Furthermore, in addition to the spatial optimization of the chamber (spatial optimization includes the spacing between the showerhead and the substrate), spatial and temporal temperature fluctuations at the showerhead can affect various deposition characteristics, including causes of thickness non-uniformity, such as greater non-uniformity. The inventors have found that for the stringent requirements of today's semiconductor manufacturing specifications, such temperature fluctuations at the showerhead may cause temperature fluctuations at the substrate level, which translate into non-uniformity of various parameters of the thin film within the wafer, including thickness, resistivity, and step coverage, among others.

[0031] Therefore, there is a need for a precursor delivery system designed for improved throughput (eg, lower ALD cycle time) and uniformity of thin films deposited in an ALD system. To address these and other sources of non-uniformity, various embodiments disclosed herein relate to a temperature controlled showerhead assembly.

[0032] Various hardware design considerations for cyclic vapor deposition systems such as ALD deposition systems are interdependent. The design optimization of one parameter may sometimes lead to the degradation of another parameter. For example, it may be desirable to reduce the volume that needs to be filled between the showerhead and the substrate during the exposure of the substrate to the precursor, so that the amount of time required to saturate the substrate surface with the precursor is shorter. However, the inventors have found that the reduction of the distance from the showerhead to the substrate can significantly increase the heat transfer between the substrate and the showerhead, thereby adversely affecting the various properties of the resulting film. In particular, the inventors have found that the showerhead design for the ALD processing station may have a significant impact on the thickness, composition and physical property uniformity of the film deposited in the deposition chamber. The inventors have especially found that controlling the spatial temperature profile of the showerhead and maintaining the relatively constant temperature of the showerhead may be important for reducing the non-uniformity in the film deposited by the ALD process. In addition, the inventors have found that it may be important to fully diffuse the precursor and / or mix the precursor with the purge gas before the precursor contacts the substrate for the uniformity of the deposited film.

[0033] In order to particularly address the above needs, a cyclic vapor deposition system according to an embodiment includes a deposition chamber configured to deposit a thin film by alternately exposing a substrate (e.g., a wafer, a semiconductor element) to a plurality of gases including a precursor, wherein the thin film deposition chamber is configured to introduce one or more gases into the thin film deposition chamber using a temperature-controlled showerhead assembly. The showerhead assembly according to various embodiments includes a showerhead body having a gas diffusion / mixing chamber formed at a central region (e.g., an upper central region) of the showerhead body through the showerhead body, wherein the diffusion / mixing chamber is configured to receive a gas from an external source and diffuse and / or mix the precursor before the gas is introduced into the ALD deposition chamber. The showerhead assembly also includes a heater (e.g., a heating element in a mesh structure) configured to supply heat to the showerhead. The showerhead assembly further includes a cooling channel in a mesh structure, which is configured to flow a coolant in the cooling channel to take away heat from the showerhead. The heating elements and cooling channels are controlled so that the showerhead is maintained within a temperature range configured for depositing the thin film.

[0034] In various embodiments, the heating element is embedded in the showerhead body, for example, disposed on a top surface of the showerhead body.

[0035] In various embodiments, the cooling passages may be formed in a component disposed alongside the showerhead body, for example, in a component directly above the showerhead body.

[0036] In various embodiments, the showerhead body has a generally flat outer surface portion at a distance from and away from a base that supports a substrate for thin film deposition. The showerhead body also has a tapered inner surface portion facing the base. The inner surface portion is connected to the outer surface portion, and the tapering causes the inner surface portion to be further away from the base at a location closer to the center of the base.

[0037] In various embodiments, the gas diffusion / mixing chamber is a conical gas diffusion and / or mixing chamber.

[0038] In various embodiments, the heater (e.g., a reticulated heating element) and the reticulated cooling channels are formed at different vertical heights and are configured such that during deposition, the inner surface of the showerhead body is maintained at a temperature at least 20° C. higher than the temperature of the liquid coolant filling the cooling channels.

[0039] In various embodiments, the sprinkler head assembly further includes a heat insulating film disposed between the cooling channel and the heating element, and the heat insulating film is configured to limit heat transfer between the cooling channel and the heating element.

[0040] The temperature controlled showerhead assembly allows, among other things, improved temperature control of the showerhead and, in turn, improved temperature of the substrate, as well as improved spatial uniformity of precursors delivered to the substrate surface, which in turn allows for improved properties of the resulting thin film, such as improved thickness and composition uniformity. When the deposited thin film is a conductor such as TiN, the system additionally allows for improved resistivity uniformity. The system additionally improves step coverage of thin films in high aspect ratio structures on the substrate.

[0041] In the following discussion, by way of example, embodiments may be described using specific precursors for specific films. For example, specific exemplary precursors may be used to describe thin film deposition and methods of depositing such thin films according to various embodiments, exemplary precursors including titanium tetrachloride (TiCl4), ammonia (NH3), and dichlorosilane (SiCl2H2) for depositing TiN and / or titanium silicon nitride (TiSiN). However, it will be understood that embodiments are not limited thereto, and inventive aspects may be applied to any suitable combination of precursors for depositing any suitable thin film, which may be formed using a cyclic deposition process such as an ALD process.

[0042] Circulating thin film deposition system

[0043] Figure 1 A thin film deposition system 100 according to an embodiment is schematically shown, and includes a deposition chamber 103 configured to deliver precursors using a temperature-controlled showerhead assembly 112. The thin film deposition system 100 includes a thin film processing station 102 having the deposition chamber 103 formed therein. A precursor delivery system 106 is configured to deliver a plurality of precursors to the deposition chamber 103. The illustrated deposition chamber 103 is configured to form a thin film on a substrate 117 disposed on a support (e.g., a susceptor) 116, which is coupled to a support column 115 under process conditions. The deposition chamber 103 further includes an injector block 108 coupled to an upper central portion of the deposition chamber 103 and configured to centrally discharge a plurality of precursors into the deposition chamber 103 through a temperature-controlled showerhead assembly 112, which forms a boundary of the deposition chamber 103. The injector block 108 may direct gases, such as precursors and purge gases, into a gas diffusion cavity before the gases, such as precursors and purge gases, are introduced into the deposition chamber 103 to contact the substrate 117. The temperature-controlled showerhead assembly 112 is configured to uniformly distribute the one or more precursors on the substrate 117 held on the pedestal 116 so that uniform film deposition occurs. The deposition chamber 103 may be equipped with a pressure monitoring sensor (P) and / or a temperature monitoring sensor (T).

[0044] The precursor delivery system 106 is configured to deliver a plurality of precursors from precursor sources (120, 124) and one or more purge gases, such as inert gases, from purge gas sources (128-1, 128-2, 134-1, 134-2) into the deposition chamber 103. Each of the precursors and the purge gases is connected to the deposition chamber 103 through a corresponding gas delivery line. The gas delivery lines further include a mass flow controller (MFC) 132 and a precursor valve for introducing the corresponding precursor and purge gas into the thin film deposition chamber 103 in their respective paths. Further advantageously, at least some of the valves may be ultrafast atomic layer deposition (ALD) valves.

[0045] For illustrative purposes only, Figure 1 In the configuration shown, the plurality of 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 precursor from the first precursor source 120 and the second precursor from the second precursor source 124 to the deposition chamber 103 through the first precursor delivery line 110 and the second precursor delivery line 114, respectively. The fast purge (RP) gas may be stored in at least two RP gas sources 128-1, 128-2. The precursor delivery system 106 is configured to deliver the RP gas from the RP gas sources 128-1, 128-2 to the deposition chamber 103 through a corresponding one of the fast purge (RP) gas delivery lines 118-1, 118-2. The continuous purge (CP) gas may be stored in at least two CP gas sources 134 - 1 , 134 - 2 . The precursor delivery system 106 is configured to deliver CP gas from the CP gas sources 134 - 1 , 134 - 2 to the deposition chamber 103 through a corresponding one of the CP gas delivery lines 113 - 1 , 113 - 2 .

[0046] The first precursor and the second precursor are configured to be delivered from the first precursor source 120 and the second precursor source 124, respectively, by independently actuating the first precursor ALD valve 140 and the second precursor ALD valve 144, which are connected in parallel before the processing station 102. In addition, the RP gas is configured to be delivered from the RP purge gas source 128-1, 128-2 by independently actuating two corresponding purge gas ALD valves 148-1, 148-2, which are connected in parallel before the processing station 102. The ALD valves 140, 144, 148-1 and 148-2 and the corresponding delivery lines connected to the processing station 102 can be arranged to feed the corresponding gases into the injector block 108 through a multi-valve block assembly, which can be attached to the cover portion of the processing station 102. In the illustrated configuration, ALD valves 140 , 144 , 148 - 1 , and 148 - 2 are the final valves before the corresponding gases are introduced into the deposition chamber 103 of the process station 102 .

[0047] By way of example only, the first precursor and the second precursor may include TiCl4 and NH3, respectively, which are delivered from respective TiCl4 and NH3 sources to the deposition chamber 103 through respective precursor delivery lines to form a thin film (e.g., a TiN thin film). The precursor delivery system 106 may also be configured to deliver argon (Ar) as a purge gas from an Ar source to the process chamber 103 through a purge gas delivery line. The purge gas may be delivered as a continuous purge (CP) gas and / or as a rapid purge (RP) gas, and the purge gas may be delivered as follows: Figure 1 1, 148-2. The CP gas may be delivered to the deposition chamber 103 without a purge gas ALD valve. Such a CP gas may act as a carrier gas and be introduced into the injector block 108 simultaneously with the precursor.

[0048] According to various embodiments, the thin film deposition system 100 may be configured for thermal ALD deposition without plasma assistance. While plasma-enhanced processes such as plasma-enhanced atomic layer deposition (PE-ALD) processes may be effective in forming conformal films on surfaces with features having relatively low aspect ratios, such processes may be less effective in depositing films in vias and cavities of substrates with features having relatively high aspect ratios. Without being limited by theory, one possible reason for this is that in some cases the plasma may not be able to reach the deeper portions of the high aspect ratio vias. In such cases, different portions of the via may be exposed to different amounts of plasma, resulting in undesirable structural effects caused by non-uniform deposition, such as a thicker film deposited near the opening of the via compared to a thinner film deposited at the deeper portions (e.g., sometimes referred to as cusping or hole formation). For these reasons, thermal cycle vapor deposition such as thermal ALD deposition may be more advantageous because such thermal processing has a weak dependence on the ability of the plasma to reach different portions of the deposited surface.

[0049] Figure 2 A perspective view of a thin film deposition system 200 including a plurality of processing stations (e.g., four processing stations) is shown. Each of the plurality of processing stations is configured to form a thin film on a substrate disposed in the deposition chamber by transporting a plurality of precursors into the deposition chamber under unique process conditions, the unique process conditions including process temperature and process pressure. In some embodiments, when the same thin film is formed at each station, the plurality of processing stations share the same process conditions. In the illustrated embodiment, there are four processing stations 202-1, 202-2, 202-3, 202-4 with corresponding showerhead assemblies. The processing stations 202-1, 202-2, 202-3, 202-4 may be, for example, single substrate processing stations, each of which is configured to deposit one or more precursors through corresponding precursor delivery lines. Although the illustrated deposition system 200 is a multi-station processing system, it will be appreciated that the embodiments disclosed herein are not limited thereto and may be implemented in any suitable single wafer or multi-wafer processing chamber.

[0050] As about Figure 1 As depicted, the deposition system 200 may include a plurality of gas (eg, precursor, purge gas) delivery lines configured to deliver precursors and purge gases to a plurality of processing stations. Figure 2In the embodiment, each of the delivery lines can start from a source connected to the MFC, and the precursor or purge gas delivery lines can be branched at the manifold 236 and send the corresponding gas to different processing stations 202-1, 202-2, 202-3, 202-4. Before reaching the corresponding processing station, each branched delivery line can be connected to an ALD valve to accurately open and close the delivery line to deliver the corresponding precursor or purge gas to the connected processing station. It should be noted that the CP gas line may not require an ALD valve because the CP gas is continuously delivered to the connected processing station. When delivered together with the precursor, the CP gas acts as a carrier gas. According to Figure 1 , Figure 2 Each of the processing stations 202 - 1 , 202 - 2 , 202 - 3 , 202 - 4 shown in the drawings includes a showerhead assembly 112 therein having an injection block 108 that cyclically delivers a plurality of precursors and purge gases into the deposition chamber 103 and onto a substrate 117 disposed on a susceptor 116 .

[0051] like Figure 2 The deposition system 200 of the exemplary embodiment shown in can particularly benefit from various combinations of high-current conduit line sections and ALD valves of the embodiments disclosed herein, such that exposure of each precursor can be substantially shortened without sacrificing desired film properties such as conformality, step coverage, and station-to-station consistency.

[0052] Sprinkler head assembly

[0053] Figure 3AA cross-sectional view of a temperature controlled showerhead assembly 300A according to some embodiments is shown. The showerhead assembly 300A includes a centrally fed showerhead body 308, which can be formed of a highly thermally conductive material, such as a metallic material, such as aluminum. The showerhead body 308 has a gas diffusion / mixing chamber 312 formed in / through the upper central region of the showerhead body 308 to receive the delivered precursor and purge gas into the diffusion / mixing chamber 312. Gas diffusion and / or mixing effects are described elsewhere herein. A deposition chamber 340 is provided in the lower portion of the showerhead body 308, into which the precursor and purge gas are introduced, and in which deposition of the thin film on the substrate occurs. An optional perforated plate 314 may be provided between the upper diffusion / mixing chamber 312 and the lower deposition chamber 340 to fluidically connect the upper diffusion / mixing chamber 312 and the lower deposition chamber 340, and to restrict and more evenly distribute the gas flowing through the diffusion / mixing chamber 312 and into the deposition chamber 340. The showerhead assembly 300A may further include a reticulated cooling channel 316 formed above the showerhead body 308. The cooling channel 316 may be arranged in a suitable pattern, such as a plurality of concentric radial rings, a serpentine pattern, etc., to cover the upper surface of the showerhead body 308. The reticulated cooling channel 316 may be configured to be connected to a heat exchanger (not shown), and have a coolant flowing in the reticulated cooling channel 316 to remove heat from the showerhead body 308. The showerhead assembly 300A may also include a temperature sensor 331 for measuring the temperature of the showerhead body 308.

[0054] Figure 3B FIG. 2 shows a cross-sectional view of another embodiment of a temperature controlled sprinkler head assembly 300B. The sprinkler head assembly 300B incorporates, among other design parameters, the temperature controlled sprinkler head assembly 300B. Figure 3AVarious design improvements of the showerhead assembly 300A described. The showerhead assembly 300B includes various features similar to those of the showerhead assembly 300A, the details of which may not be repeated herein for the sake of brevity. For example, a showerhead body 308 made of a thermally conductive material (e.g., metal) forms an upper gas diffusion / mixing chamber 312 and a lower deposition chamber 340, and a perforated plate 314 is disposed between the upper gas diffusion / mixing chamber 312 and the lower deposition chamber 340. The perforated plate 314 can be configured to fluidly connect the diffusion / mixing chamber 312 to the deposition chamber 340, and to restrict the gas from the diffusion / mixing chamber 312 to enter the deposition chamber 340, and to more evenly distribute the gas from the diffusion / mixing chamber 312 to the deposition chamber 340. The showerhead body 308 is configured to receive precursors and purge gases through the gas diffusion / mixing chamber 312 and distribute the precursors and purge gases to the thin film deposition chamber 340.

[0055] The sprinkler head assembly 300B also has a plurality of cooling channels formed above the sprinkler head body 308. In addition, Figure 3B The sprinkler head assembly 300B shown in FIG. 3 has a heater 330 disposed between the sprinkler head body 308 and the cooling channel 316. The heater 330 can be implemented to contact the sprinkler head body 308. The heater 330 can be a single piece or a plurality of heating elements (e.g., heating elements in a mesh structure) arranged in a pattern (e.g., a ring pattern or a serpentine pattern). An insulating layer 318 can be disposed between the cooling channel 316 and the heater 330 to limit heat transfer from the heater 330 to the cooling channel 316. The cooling channel 316, the insulating layer 318, and the heater 330 can be configured to control the temperature of the sprinkler head body 308, as further described elsewhere herein.

[0056] like Figure 3A and Figure 3B As shown in FIG. 3 , the housing 304 surrounds the sprinkler head body 308 and fills the volume between the cover portion 348 and the sprinkler head body 308, the cover portion 348 forming the top cover of the sprinkler head assembly 300. Figure 3B As can be seen in FIG. 3 , a cooling channel in a mesh structure may be formed in a portion of the housing 304 above the showerhead body 308. The housing 304 forms an outer circumferential wall of the deposition chamber 340. Figure 3BAs shown in FIG, below the deposition chamber 340, a pedestal 354 is configured to hold a substrate, and the pedestal 354 is coupled to a support column 352 below. The top surface of the pedestal 354 is configured to hold a substrate (e.g., a wafer) 356 for thin film deposition. The circumferential wall of the housing 304 is connected to a structure surrounding the pedestal 354 and the support column 352. The connection between the circumferential wall 304 and the surrounding structure of the pedestal 354 can form an airtight seal, so that the deposition chamber 340 is fluidly isolated from the external environment.

[0057] The inventors have discovered that several factors related to the structure of the showerhead body 308 are important in determining the flow pattern of the precursors in the deposition chamber 340 and the quality (eg, uniformity) of the thin film deposition. Figure 4 is from Figure 3B A partial cross-sectional view taken from the cross-sectional view of FIG. 3 is used to show the diffusion / mixing chamber 312 located at the upper center of the sprinkler head body 308. Figure 4 As shown in , the diffusion / mixing cavity 312 can be conical in shape, having a steeply tapered sidewall 311, wherein the diameter of the widest bottom portion of the cone is less than the height. The diameter of the bottom portion of the diffusion / mixing cavity 312 can be 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, or a value within a range defined by any of these values. The tapered sidewall 311 of the diffusion / mixing cavity 312 has a first taper angle α between it and a vertical line 313 perpendicular to the top surface of the base 354. According to some embodiments, the taper angle α can be less than 12°, 10°, 8°, 6°, or a value within a range defined by any of these values, for example 4.5°. The inventors have discovered that the steeply tapered sidewall 311 can be critical for advanced semiconductor applications, as further described elsewhere herein.

[0058] refer to Figure 4 The showerhead body 308 also incorporates an injector block 320 located in an upper portion of the diffusion / mixing chamber 312. The diffusion / mixing chamber 312 is connected to inlet passages 324a and 324b and is configured to receive precursor and purge gases entering through the inlet passages 324a and 324b.

[0059] The inventors have found that the arrangement of the gas inlet channels defined within the injector block can be an important embodiment for uniform distribution of the precursor and purge gases. In particular, the inventors have found that when the inlet gas channels are arranged to extend in a vertical direction, the gas incident on the substrate (e.g., Figure 3BThe final distribution of gas on the substrate 356 shown in may be undesirably concentrated around the line of sight position, for example, around the central portion of the substrate. Without being bound by any theory, this phenomenon may be because the velocity profile of the jet from the vertically arranged inlet channels is generally parabolic in shape, with higher velocities in the central region and lower velocities toward the sides of the jet. In this way, the fluid can primarily impact downward onto the central portion of the substrate, with limited lateral flow and diffusion. If the precursor is dispensed with the carrier gas and locally concentrated in the inlet channel, when the fluid with the precursor reaches the substrate, limited diffusion and mixing may result in uneven distribution. To address this concern, in the exemplary design shown, the inlet gas channels 324a and 326a of the injector block 320 extend at substantially non-vertical and inclined angles, such as Figure 4 It can be seen in.

[0060] Figure 5 3 is a perspective view of an embodiment of a sprinkler head body 308 in which the outer wall of the diffusion / mixing chamber 312 rises from the top surface of the diffusion / mixing chamber 312. Two inlet tubes 324 and 326 having inlet passages 324a and 324b formed therein, respectively, may be coupled to the top portion of the diffusion / mixing chamber 312. As can be seen, the inlet tubes 324 and 326 are angled with a vertical axis that is perpendicular to the top surface of the sprinkler head body 308.

[0061] exist Figure 6 In FIG. 3 , the diffusion / mixing chamber 312 and the connected inlet passages 324a and 326a are constructed for computational fluid dynamics (CFD) simulation purposes. The diffusion / mixing chamber 312 is bounded at the lower end by a perforated plate 314 . Figure 7 It is shown in Figure 6 , showing the flow path of a fluid (e.g., a precursor or purge gas) entering the top end through inlet channels 324a and 326b. As can be clearly seen in the simulated flow path traces, the angled or inclined inlet channels 324a and 326b cause the gaseous fluid to enter the mixing chamber 312 at an angle from the top and collide with the sidewalls of the mixing chamber 312 at least once. Such collisions can cause eddies and turbulence to form in the fluid, thereby enhancing mixing and diffusion, and can result in more uniform precursor dispensing in the gaseous fluid as it enters the deposition chamber below.

[0062] like Figure 3A , Figure 3B and Figure 6, downstream of the diffusion / mixing chamber 312 is a perforated plate 314 having a plurality of perforations formed through the perforated plate 314. The perforations may be of the same size or of different sizes. The perforations may restrict flow and allow the precursor and purge gases to pass more evenly through each of the perforations, thereby more evenly distributing the gases to the deposition chamber 340 downstream of the perforated plate 314.

[0063] Figure 8 is from Figure 3B A partial cross-sectional view is taken to show more details of the edge portion of the deposition chamber 340. As can be seen, the deposition chamber 340 is bounded by the tapered lower surface of the showerhead body 308 at the upper side and the upper surface of the base 354 at the lower side. The lower surface of the showerhead body 308 tapers in a shallow manner, thereby forming a second taper angle β between the tapered lower surface and a plane parallel to the upper surface of the base 354 (or substrate 356). The inventors have found that the showerhead body 308 with a tapered lower surface allows a substantial reduction in the volume of the deposition chamber 340 relative to the showerhead body 308 with a flat surface facing the substrate 356. In addition, the inventors have found that the tapered volume of the deposition chamber 340 allows a more uniform gas flow rate to be incident on the substrate surface. According to various embodiments, the second taper angle β may be less than 12°, 10°, 8°, 6°, 4°, or a value in a range defined by any of these values, for example, 9.0°. Those skilled in the art will appreciate that a smaller second cone angle β corresponds to a reduced volume of the deposition chamber 340. The reduced volume in turn allows for faster cycle times, in part because less time may be required to purge the volume of unreacted precursor gas between precursor pulses.

[0064] Another consideration is Figure 8 356 . The wafer-to-showerhead body gap S shown in FIG. 35 is between the lowest portion of the showerhead body 308 and the upper surface of a substrate (e.g., wafer) 356 disposed on a pedestal 354. According to an embodiment, the gap S is less than 0.3", 0.25", 0.2", 0.15", 0.10", or a value within a range defined by any of these values, such as 0.15". The inventors have found that a gap S of 0.15" or 0.10" can reduce the volume of the deposition chamber 340 between the showerhead and the substrate by 36% and 45%, respectively, relative to a gap S of 0.25". A smaller gap S can also help improve the uniformity of thin film deposition on the substrate 356. The precursor can be configured to be discharged from the gap S surrounding the substrate 356. A smaller gap S can create a greater fluid resistance and ensure that the precursor flows more uniformly toward the circumferential edge in all radial directions. Importantly, the gap S has a substantially narrow tolerance range, especially when the gap S is smaller.

[0065] Temperature Control of Sprinkler Head Assemblies

[0066] As described above, in order to enhance the temperature control and response of the sprinkler head assembly, the sprinkler head assembly according to the embodiment includes a reticulated cooling channel and a reticulated heating element. The inventors have found that the temperature control and response are particularly effective when the cooling channel and the heating element are formed at different vertical heights. In particular, the inventors have found that it is advantageous to arrange the reticulated heating element closer to the upper surface of the sprinkler head body relative to the cooling channel. In addition, in some embodiments, the sprinkler head assembly also includes a thermal insulation film vertically arranged between the cooling channel and the reticulated heating element. Such an arrangement can particularly achieve improved control of the temperature difference vertically across the sprinkler head body, as well as its faster time response.

[0067] CFD simulations have been performed to optimize the design parameters and features of the deposition chamber 340, such as those described above with respect to FIG. 3A to FIG. 8 Design factors depicted. Design parameters / features may include a first cone angle α, a second cone angle β, and a gap S. In particular, under certain assumptions, CFD simulations have been performed to optimize the precursor concentration uniformity and flow velocity distribution on the substrate associated with the first cone angle α, and it was found that a first cone angle of less than 10° is substantially better than a first cone angle of 11°. For the second cone angle β, the simulation results show that the precursor concentration is most uniform when the second cone angle is about 5.5°, and the velocity distribution is best when the second cone angle is about 6.5°. Regarding the gap S from the wafer to the showerhead body, the simulation results show that when the gap S is about 0.158", compared to 0.258", the concentration and velocity distribution show substantial improvements. CFD simulations were also performed to compare different embodiments of the injector block. The following table shows an exemplary CFD simulation result comparison in terms of deposition chamber volume reduction:

[0068]

[0069]

[0070] Temperature control of the sprinkler head body

[0071] In addition to the above FIG. 3A to FIG. 8 In addition to considering structural factors associated with the uniformity of gas delivery to the substrate and the volume of the deposition chamber 308, the inventors have discovered that controlling the temperature of the showerhead body 308 can be important for controlling the uniformity of the deposited film in thickness as well as the physical properties, including chemical composition and resistivity.

[0072] Return to reference Figure 3B, the pedestal 354 may include a heater embedded in the pedestal 354 to heat the substrate 356 in the deposition chamber 340. Heat from the substrate 356 may be transferred to the lower surface of the showerhead body 308, for example, by radiation and convection to a lesser extent. On the upper side of the deposition chamber 340, the temperature of the showerhead body 308 may be controlled by a combination of a heater 330 coupled to the upper portion of the showerhead body 308, a plurality of cooling channels 316 disposed above the showerhead body 308, and an insulating layer 318 disposed between the cooling channels 316 and the heater 330. In this way, the temperature in the deposition chamber 340 may be controlled to obtain optimized thin film deposition. Fig. 9 is an exploded perspective view of the sprinkler head assembly 300B, further illustrating the relationship of the heater 330, the insulation layer 318, and the sprinkler head body 308. The cooling passage 316 is embedded in the top portion of the exploded view and is not visible in the viewing angle.

[0073] Move to Fig.10 The sprinkler head assembly 300B further includes temperature sensors 334, 336, and 338, which are located at different positions having different distances from the center, as viewed in the top view direction. Figure 3A Unlike the temperature sensor 331 shown embedded in the upper portion of the housing 304 of the sprinkler head assembly 300A, the temperature sensors 334, 336, 338 are embedded in the sprinkler head body 308 of the sprinkler head assembly 300B. As described above, the sprinkler head body 308 can be made of a highly conductive material such as aluminum. Thus, the temperature distribution within the sprinkler head body 308 can be within a narrow range. The inventors have found that the temperature sensors 334, 336, 338 embedded in the solid sprinkler head body 308 formed of a highly conductive material can optimize the response time of temperature sensing. The inventors have also found that for closed-loop temperature control with a fast response time, the temperature sensors 334, 336, 338 can be embedded about 0.1" above the tapered lower surface facing the substrate 356 of the sprinkler head body 308 within a distance of 0.5", 0.3", 0.1", or within a range defined by any of these values. Figure 8 In the partial cross-sectional view of FIG. 5 , the locations of two such temperature sensors are indicated by reference numerals 334 and 336 .

[0074] As described above, it may be desirable to control the temperature of the deposition chamber 340 (e.g., the lower surface of the deposition chamber 340) within a specific temperature range for depositing a specific film. In particular, for several reasons, controlling the temperature of the showerhead body 308 within a temperature range may be important for maintaining temperature control during deposition of a thin film on a substrate. For example, if the temperature of the showerhead is too low, undesirable deposition may occur on the surface of the showerhead. Such deposition may, among other things, cause changes in the surface emissivity and particle generation of the showerhead. On the other hand, if the temperature is too high, secondary heating of the substrate may occur due to radiation. An analysis has been performed to guide the design of a temperature control system and heat transfer solution for the showerhead body 308.

[0075] Fig.11 A partial cross-sectional view is shown, which shows the connection to the sprinkler head body 308 ( Figure 3A and Figure 3B ) includes a cooling channel 316 in a mesh structure. As described above, the cooling channel 316 in a mesh structure formed in the upper portion of the housing 304 above the showerhead body 308 is configured to take heat away from the showerhead body 308. The cooling channel 316 is configured to flow a coolant circulated by a heat exchanger (not shown) in the cooling channel 316 at a fixed temperature so that the upper surface of the showerhead body 308 adjacent to the cooling channel 316 is maintained at a relatively constant temperature. For example, the coolant can be maintained at a temperature within a range of about 100° C., 120° C., 140° C., 160° C., 180° C., 200° C., 220° C., or any of these values. The temperature of the coolant is determined by the film to be deposited and the process configured to deposit the film in the deposition chamber 340.

[0076] exist Fig.11 , the temperature at the lower surface of the housing 304 that contacts the sprinkler head body 308 is designated as T liner For analytical purposes, the temperature T liner As an example, the contact thermal resistance between the housing 304 and the upper surface of the sprinkler head body 308, such as R contact and the thermal resistance of the sprinkler head body 308, such as R Al The heat transfer rate from the lower surface of the sprinkler body 308 to the lower surface of the housing 304 can be calculated based on known or estimated values ​​of T to maintain the lower surface of the sprinkler body 308 at the indicated temperature, for example, T sh The calculations reveal that in order to maintain a temperature difference (eg, ΔT) between the lower surface of the showerhead body 308 facing the wafer and the lower surface of the housing 304 exceeding 100° C. (ΔT=T sh -T liner), the amount of heat transfer rate required exceeds 30,000W, which is an order of magnitude higher than the typical power supply for heating power supplied to semiconductor processing chambers. Conveniently, in the industry, the power supply for deposition chamber 340 can be as high as 750W. Applying an amount of 750W in the equation above that produces a heat transfer rate of 30,000W and using the same assumptions, calculations show that the expected temperature difference ΔT is only about 4 degrees. Starting from a heat transfer rate of 750W, this temperature difference across the thickness of the showerhead body is too narrow to support effective temperature control of the showerhead body 308 for the purpose of maintaining the temperature of the deposition chamber 340.

[0077] The calculations performed as described above show that Figure 3A The sprinkler head assembly 300A shown in FIG. 3 is thermally engineered in the vertical stacking direction to improve the efficiency of the closed-loop temperature control of the sprinkler head body 308. The inventors have discovered that this need arises, in part, because of the high thermal conductivity of the aluminum material. As discussed below, the inventors have further discovered that, according to embodiments, introducing a series thermal resistor in the vertical direction can improve thermal performance. Figure 3B , Fig. 9 and Fig.11 As shown in FIG. 3 , an insulating layer 318 is disposed between the housing 304 and the sprinkler head body 308 for the purpose of introducing additional series thermal resistance.

[0078] The inventors have found that controlled thermal isolation between the housing 304 and the showerhead body 308 may be critical to maintaining a substantial temperature difference ΔT, such as 10°C, 20°C, 30°C, 40°C, 50°C, or a range defined by any of these values, and to maintaining a narrow temperature range at the lower surface of the showerhead body 308 during deposition operations. For effective thermal isolation, in addition to physical separation, the inventors have found that inserting an appropriate insulating layer (e.g., insulating layer 318) may be effective. The insulating layer 318 is used to slow down heat transfer by causing a substantial temperature across the thickness of the insulating layer 318.

[0079] The basic heat transfer analysis model used above involving a range of thermal resistances is used to perform the analysis. In addition to the contact thermal resistance (R contact ) and the thermal resistance (R Al), the additional thermal resistance caused by the insulation layer 318 is added to the heat transfer model. As constructed, the lower surface of the sprinkler head body 318 can be maintained at a suitable temperature, for example, at least 20°C higher than the temperature of the liquid coolant circulating in the cooling channel 316. The inventors have discovered that the insulation layer 330 can be a suitable polymer film having a thermal resistance similar to that of polyetheretherketone (PEEK). It has been observed that using a PEEK layer as the insulation layer 318, a ΔT of 40°C between the lower surface of the sprinkler head body 308 and the lower surface of the housing 304 can be maintained, and most of the 40°C is across the PEEK insulation layer 318.

[0080] As mentioned above about Figure 3B As described, as part of a solution to maintain the showerhead body 308 in a desired temperature range for depositing various types of thin films, a heater 330 can be coupled to the upper portion of the showerhead body 308 to supply thermal energy to heat the showerhead body 308. The heater 330 can be a mesh-like structure of heating elements arranged to cover a large area of ​​the upper portion of the showerhead body 308. The heater 330 can be configured to supply a power of 250 W, 500 W, 750 W, 1000 W, 1250 W, 1500 W, 1750 W, 2000 W, or a power within a range defined by any of these values. For Figure 3B , assuming that the heater 330 is configured to supply a maximum power of 750 W, and that the lower surface of the showerhead body 308 can receive up to, for example, 500 W of power from the deposition chamber 340 and the substrate 356 below, for example, by radiation, using the calculations of the above-mentioned heat transfer model, it is shown that a 0.029" (0.7 mm) thick insulating layer 318 (e.g., a PEEK layer) can maintain a suitable ΔT, for example, 40° C., between the lower surface of the showerhead body 308 and the lower surface of the housing 304. It may be desirable to use a smaller power supply to maintain a ΔT of 40° C. In some embodiments, assuming that the maximum radiation from the substrate 356 and the deposition chamber 340 is maintained at 500 W, and a maximum power supply of 250 W is used for the temperature T at the lower surface of the showerhead body 308 sh Based on the dead-loop control, the calculated surface, 0.055" (1.4mm) thickness of the insulating layer 318 may be effective. 0.029" thickness or 0.055" thickness is a small thickness.

[0081] Using the heater 330 and the cooling channel 316 in a mesh structure and the temperature sensors 334, 336, 338, with the insulation layer 318 disposed between the heater 330 and the cooling channel 316, the showerhead assembly 300 can be configured to have a closed-loop temperature control system for maintaining the lower surface of the showerhead body 308 within a relatively small temperature range during the thin film deposition operation in the deposition chamber 340. In this configuration, the cooling channel 316 in a mesh structure and the heater 330, which are disposed at different vertical heights and are in thermal communication with each other and with the showerhead body 308, are controlled together. Thus, the temperature of the lower surface of the showerhead body 308 facing the substrate 356 is maintained at a temperature at least 20° C. higher than the temperature of the lower surface of the housing 304, or maintained at a temperature at least 20° C. higher than the temperature of the liquid coolant circulating in the cooling channel 316 during operation. In some embodiments, the temperature of the lower surface of the showerhead body 308 can be maintained at least 40° C. higher than the temperature of the liquid coolant circulating in the cooling channel 316. Depending on the temperature of the coolant flowing in the coolant channel 306, the lower surface of the showerhead body 308 can be maintained at an average temperature of 120° C., 140° C., 160° C., 180° C., 200° C., 240° C., or a temperature within a range defined by any of these values, such as within a range of 160° C. to 230° C., during deposition of a thin film on the substrate 356, and the lower surface of the showerhead body 308 can be at a temperature above 300° C., 350° C., 400° C., 450° C., 500° C., 600° C., 650° C., or a temperature within a range defined by any of these values.

[0082] Fig.12 Temperature measurements at the lower surface of the showerhead body 308 are shown. It can be seen that the temperature within the showerhead body can be maintained within a relatively narrow range. For example, for a wafer temperature of 620°C, the lowest curve corresponding to a chamber pressure of 5 Torr remains between about 220°C and about 270°C. Another observation is the effect of the pressure in the deposition chamber 340 on the temperature measurement. For example, at TC6, the temperature drops from over 280°C at a pressure of 1 Torr to a temperature of about 230°C when the pressure is increased to 5 Torr.

[0083] Fig.13 An exemplary precursor delivery sequence for delivering one or more precursors using a temperature controlled showerhead assembly (e.g., showerhead assembly 300B) according to some embodiments is shown by way of example only. The first precursor inlet and the second precursor inlet at the injector block are connected to the injector block as described above, for example, with respect to Figure 1 The first precursor delivery line and the second precursor delivery line described and arranged. Fig.13The two graphs in show two precursor delivery sequences. In each graph, the vertical axis is flow rate (Q) and the horizontal axis is time (t). The ALD cycles of both graphs include a first sub-cycle for exposing the substrate 356 to a first precursor (e.g., TiCl4) and a second sub-cycle for exposing the substrate 356 to a second precursor (e.g., NH3). Each of the precursor ALD valves can be a three-port valve, and in some embodiments, a continuous purge (CP) gas, such as an inert gas, can flow through the ALD valve while the substrate 356 is exposed to the first precursor and / or the second precursor. In the exemplary graphs shown, the CP gas used is N2. When introduced simultaneously into the deposition chamber 340, the CP gas and the precursor are mixed in the diffusion / mixing chamber 312 before being introduced into the deposition chamber 340, as described above. In Fig.13 In the illustrated embodiment of , each of the first sub-cycle and the second sub-cycle further comprises a quick purge (RP) by an inert gas after exposure to one or both of the first precursor and the second precursor, respectively. Fig.13 In FIG. 1 , the fast purge gas is N 2 , the same as the continuous purge gas used. The fast purge can be performed using a purge ALD valve as described above. The fast purge has a flow rate that is higher in magnitude than the continuous purge, such as Fig.13 As shown in .

[0084] The deposition system 100 according to the above-described embodiments is particularly advantageous for forming thin films on substrates including high aspect ratio structures having an opening width of less than 1 micrometer, 500 nm, 200 nm, 100 nm, 50 nm, 20 nm, or an opening width in a range defined by any of these values, having an aspect ratio of more than 5, 10, 20, 50, 100, 200, or an aspect ratio in a range defined by any of these values, and having an area density such that the surface area is greater than the surface area of ​​a planar substrate as described above. Substrates having such morphologies can be conformally coated with thin films including TiN, TiSiN and / or TiAlN, or substrates having such morphologies can be conformally coated with another suitable thin film according to embodiments with a step coverage as defined above, the step coverage exceeding 50%, 60%, 70%, 80%, 90%, 95%, or having a value in a range defined by any of these values, or having a higher value.

[0085] One measure of conformality in the context of high uniformity high aspect ratio structures is referred to herein as step coverage. High aspect ratio structures may be, for example, vias, holes, trenches, cavities, protrusions, or the like. By way of illustrative example, Fig.14A semiconductor structure 500 is schematically shown with an exemplary high aspect ratio structure 516 formed therein to illustrate some exemplary metrics for defining and / or measuring the conformality of a thin film formed on the high aspect ratio structure. The illustrated high aspect ratio structure 516 is coated with a thin film 512, such as a TiN layer, deposited according to some embodiments, the thin film 512 having different thicknesses at different portions of the high aspect ratio structure. As described herein, the high aspect ratio structure has an aspect ratio greater than 1, for example, defined as the ratio of the depth or height (H) divided by the width (W) at the opening area of ​​the high aspect ratio structure 516. In the illustrated example, the high aspect ratio structure 516 is a via formed through a dielectric layer 508, such as an intermetallic dielectric (ILD) layer, disposed on a semiconductor substrate 504, such that the bottom surface of the high aspect ratio structure 516 exposes the semiconductor 504 below. The thin film 512 may coat different surfaces of the high aspect ratio structure 516 with different thicknesses. As described herein, one metric used to define and measure the conformality of a film formed with a high aspect ratio is called step coverage. Step coverage can be defined as the ratio between the thickness of the film at the lower or bottom region of the high aspect ratio structure and the thickness of the film at the upper or top region of the high aspect ratio structure. The upper or top region can be a region of the high aspect ratio structure at a relatively small depth, such as a region at 0% to 10% of H measured from the top of the opening or a region at 0% to 25%. The lower or bottom region can be a region of the high aspect ratio structure at a relatively large depth, such as a region at 90% to 100% of H measured from the top of the opening or a region at 75% to 100%. In some high aspect ratio structures, step coverage can be defined or measured by the ratio of the thickness of the film 512A formed at the bottom surface of the high aspect ratio structure to the thickness of the film 512C formed at the upper or top sidewall surface of the high aspect ratio structure. 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, the step coverage may be more consistently defined or measured by the ratio of the thickness of the film 512B formed at the lower or bottom sidewall surface of the high aspect ratio structure to the thickness of the film 512C formed at the upper or top sidewall surface of the high aspect ratio structure.

[0086] Due at least in part to the relatively constant temperature uniformity of the showerhead body 308 and the efficient diffusion and / or mixing of the precursor and the purge gas, the deposition system 100 according to the embodiment results in substantial improvement in step coverage in high aspect ratio structures. By employing a temperature controlled showerhead assembly 300B according to the embodiment, high aspect ratio structures having aspect ratios exceeding 1, 2, 5, 10, 20, 50, 100, 200, or having aspect ratios within a range defined by any of these values, can be conformally coated with a thin film according to the embodiment, such as a TiN film, having a step coverage exceeding 70%, 80%, 90%, 95%, or having a step coverage within a range defined by any of these values ​​as defined herein. The step coverage thus obtained represents an improvement of 5%, 10%, 15%, 20%, or a value within a range defined by any of these values ​​relative to the corresponding step coverage obtained using a showerhead assembly of a similar thin film deposition system without proper temperature control.

[0087] Additional Example I:

[0088] 1. A temperature controlled showerhead assembly configured to deliver a plurality of precursors into an atomic layer deposition (ALD) chamber, the showerhead assembly comprising:

[0089] a showerhead including a solid body portion and a gas diffusion cavity formed through the showerhead at a central region of the showerhead, wherein the showerhead is configured to diffuse a precursor in the gas diffusion cavity prior to introducing the precursor into the ALD chamber;

[0090] a reticulated cooling channel formed above the sprinkler head and configured to conduct heat away from the sprinkler head; and

[0091] A reticulated heating element contacts the solid body portion and is configured to supply heat to the sprinkler head.

[0092] 2. A temperature controlled showerhead assembly configured to deliver a plurality of precursors into an atomic layer deposition (ALD) chamber, the showerhead assembly comprising:

[0093] A spray head, the spray head comprising:

[0094] a solid body portion having a substantially flat outer surface facing away from the base and an inner surface facing the base, the inner surface being tapered such that the thickness of the solid body portion increases from a central region of the solid body portion toward an edge portion, and

[0095] a tapered gas diffusion chamber formed through the solid body portion at a central region of the solid body portion and configured to diffuse a precursor prior to introducing the precursor into the ALD chamber; and

[0096] A mesh-structured cooling channel and a mesh-structured heating element, the mesh-structured cooling channel and the mesh-structured heating element are formed at different vertical heights and are configured so that during deposition, the inner surface of the solid body portion is maintained at a temperature at least 20°C higher than the temperature of the liquid coolant filling the cooling channel.

[0097] 3. A temperature controlled showerhead assembly configured to deliver a plurality of precursors into an atomic layer deposition (ALD) chamber, the showerhead assembly comprising:

[0098] a showerhead including a solid body portion and a gas diffusion cavity formed through the showerhead at a central region of the showerhead, wherein the showerhead is configured to diffuse a precursor in the gas diffusion cavity prior to introducing the precursor into the thin film deposition chamber;

[0099] A cooling channel in a mesh structure, the cooling channel in a mesh structure is formed above the spray head and is configured to conduct heat away from the spray head;

[0100] a reticulated heating element configured to supply heat to the sprinkler head; and

[0101] A heat insulating film is vertically disposed between the cooling channel and the heating element and is configured to limit heat transfer between the cooling channel and the heating element.

[0102] 4. The sprinkler head assembly of example 2 or 3, wherein the heating element contacts a solid portion of the sprinkler head.

[0103] 5. The sprinkler head assembly of example 1 or 3, wherein the solid body portion has a substantially flat outer surface facing away from the base and an inner surface facing the base, the inner surface being tapered such that the thickness of the solid body portion increases toward an edge portion thereof.

[0104] 6. The sprinkler head assembly of example 1 or 3, wherein the gas diffusion chamber is a conical gas diffusion chamber.

[0105] 7. A spray head assembly according to Example 1 or 3, wherein the cooling channels in a mesh structure and the heating elements in a mesh structure are formed at different vertical heights and are configured so that during deposition, the inner surface of the solid body portion is maintained at a temperature at least 20°C higher than the temperature of the liquid coolant filling the cooling channels.

[0106] 8. The sprinkler head assembly of example 1 or 2, wherein the cooling channel and the heating element are thermally isolated from each other by a thermal insulation film vertically disposed between the cooling channel and the heating element.

[0107] 9. The sprinkler head assembly of any of the above examples, wherein the sprinkler head further comprises a plurality of thermal links embedded in the solid body portion and disposed within 0.5 inches of an inner surface of the solid body portion facing the base.

[0108] 10. The sprinkler head assembly according to any one of the above examples, wherein the outer surface of the sprinkler head is inclined in a radial direction to have a neck angle of less than 10 degrees relative to a horizontal direction.

[0109] 11. The sprinkler head assembly according to any one of the above examples, wherein the gas diffusion chamber is a conical diffusion chamber, the conical diffusion chamber having a side wall of the conical diffusion chamber having a conical angle of less than 10 degrees relative to a vertical direction.

[0110] 12. The sprinkler head assembly of any of the above examples, wherein a distance between a bottommost surface of the solid body portion facing the base and the base is less than 0.3".

[0111] 13. The sprinkler head assembly of any of the above examples, wherein the gas diffusion chamber is a conical diffusion chamber having a diameter that is less than 30% of the diameter of the sprinkler head.

[0112] 14. A sprinkler head assembly according to any one of the above examples, wherein the sprinkler head assembly further comprises an injector block disposed above the sprinkler head, wherein the injector comprises a plurality of injector channels formed in the injector and configured to direct the precursor into the gas diffusion chamber in an inclined direction.

[0113] 15. The showerhead assembly of example 14, wherein the oblique direction is such that precursor exiting from the injector passage is directed toward a sidewall of the gas diffusion chamber.

[0114] 16. The showerhead assembly of Example 14, further comprising a mixing chamber formed within the gas diffusion chamber, and wherein the plurality of injector channels are configured to direct precursors into the mixing chamber prior to introducing the precursors into the ALD chamber.

[0115] 17. The showerhead assembly of example 16, wherein the mixing chamber comprises a plurality of injectors configured to inject precursors into the ALD chamber.

[0116] 18. The sprinkler head assembly of any of the examples, wherein the cooling channel and the heating element do not overlap in a vertical direction.

[0117] 19. The sprinkler head assembly of any of the preceding examples, wherein the cooling channel and the heating element are vertically disposed by a thermal insulation film comprising a polymer film.

[0118] 20. The sprinkler head assembly of example 19, wherein the polymer film comprises polyetheretherketone (PEEK).

[0119] 21. The sprinkler head assembly of example 19, wherein the polymer film has a thickness between 0.020 inches and 0.040 inches.

[0120] 22. The sprinkler head assembly of any of the preceding examples, wherein the cooling passage is filled with a liquid coolant maintained at a substantially constant temperature by a heat exchanger.

[0121] 23. The sprinkler head assembly of any of the preceding examples, wherein the heating element comprises a resistive heating element.

[0122] 24. The showerhead assembly according to any of the above examples, wherein the reticulated cooling channels and the reticulated heating elements are configured such that during deposition, the inner surface of the solid body portion facing the susceptor is maintained at a temperature of 150°C to 240°C.

[0123] 25. The sprinkler head assembly of example 24, wherein the cooling channel is filled with a liquid coolant maintained at a substantially constant temperature of 120°C to 220°C.

[0124] 26. The sprinkler head assembly of example 24, wherein the heating element is configured to dissipate 500W to 2000W.

[0125] 27. The showerhead assembly of example 24, wherein the ALD chamber comprises a pedestal configured to heat the substrate to between 300°C and 700°C.

[0126] 28. The sprinkler head assembly of any of the preceding examples, wherein the heating element does not contact the solid body portion.

[0127] 29. The sprinkler head assembly of any of the preceding examples, wherein the heating element does not contact the cooling channel.

[0128] Additional Example II:

[0129] 1. A temperature controlled showerhead assembly configured to deliver a plurality of gases into a circulating deposition chamber, the showerhead assembly comprising:

[0130] a showerhead body including a cavity extending through the showerhead body and formed at a central region of the showerhead body, wherein the cavity is configured to diffuse or mix the gas before introducing the gas into the deposition chamber;

[0131] a reticulated cooling channel configured to conduct heat away from the sprinkler head body; and

[0132] A heating element in a mesh structure is configured to supply heat to the sprinkler head body, wherein the heating element in a mesh structure is disposed closer to an upper surface of the sprinkler head body than to a cooling channel.

[0133] 2. The sprinkler head assembly of example 1, wherein the cooling channel and the heating element in a mesh structure are disposed at different vertical heights.

[0134] 3. The sprinkler head assembly of example 2, wherein the cooling channel and the reticulated heating element are thermally isolated from each other by an insulating layer disposed between the cooling channel and the reticulated heating element.

[0135] 4. The sprinkler head assembly of example 3, wherein cooling channels and the reticulated structure of heating elements laterally surround the cavity.

[0136] 5. The sprinkler head assembly of example 4, wherein the cavity has a truncated cone shape that is elongated in a vertical direction and has a width that increases in a direction toward a base disposed below the sprinkler head assembly.

[0137] 6. A sprinkler head assembly according to Example 1, wherein the sprinkler head assembly further comprises an injector block disposed above the sprinkler head body, wherein the injector block comprises a plurality of channels formed in the injector block for flowing different gases to direct the different gases into the cavity in different directions.

[0138] 7. The showerhead assembly of example 6, wherein the chamber is configured to mix the two different gases prior to introducing the two different gases into the deposition chamber.

[0139] 8. The showerhead assembly of example 7, wherein one of the two different gases is an inert gas and the other of the two different gases is a reactant.

[0140] 9. A temperature controlled showerhead assembly configured to deliver a plurality of gases into a circulating deposition chamber, the showerhead assembly comprising:

[0141] a sprinkler head body having a generally flat outer surface facing away from the base and an inner surface facing the base, the inner surface being tapered so that the thickness of the sprinkler head body increases from a central region toward an edge portion of the sprinkler head body;

[0142] a cavity formed through the showerhead body at the central region and configured to diffuse or mix gases prior to introduction into the deposition chamber; and

[0143] The cooling channels in a reticulated structure and the heating elements in a reticulated structure are formed at different vertical heights.

[0144] 10. The showerhead assembly of Example 9, wherein the reticulated cooling channels and the reticulated heating elements are configured such that during deposition, the inner surface of the showerhead body is maintained at a temperature at least 20° C. higher than the temperature of the liquid coolant filling the cooling channels.

[0145] 11. The sprinkler head assembly of example 9, wherein the cooling channel and the heating element in the mesh structure are thermally isolated from each other by a thermal insulation film vertically disposed between the cooling channel and the heating element.

[0146] 12. The sprinkler head assembly of example 9, further comprising a plurality of thermal links disposed within 0.5 inches of an inner surface of the sprinkler head body that faces the base.

[0147] 13. The sprinkler head assembly of example 9, wherein the outer surface of the sprinkler head body is inclined in a radial direction to have a neck angle of less than 10 degrees relative to a horizontal direction.

[0148] 14. The sprinkler head assembly of example 9, wherein the cavity is a tapered cavity, the tapered cavity having a sidewall of the tapered cavity having a taper angle of less than 10 degrees relative to a vertical direction.

[0149] 15. The sprinkler head assembly of example 9, wherein a distance between a bottommost surface of the sprinkler head body facing the base and an upper surface of the base is less than 0.3".

[0150] 16. A temperature controlled showerhead assembly configured to deliver a plurality of gases into a circulating deposition chamber, the showerhead assembly comprising:

[0151] a showerhead body including a cavity extending through the showerhead body and formed at a central region of the showerhead body, wherein the cavity is configured to diffuse or mix the gas prior to introducing the gas into the deposition chamber;

[0152] A cooling channel in a mesh structure, the cooling channel in a mesh structure is formed above the spray head body and is configured to conduct heat away from the spray head;

[0153] a reticulated heating element configured to supply heat to the sprinkler head; and

[0154] A heat insulating film is vertically arranged between the cooling channel and the heating element in a mesh structure.

[0155] 17. The sprinkler head assembly of example 16, wherein the lateral footprint occupied by the reticulated cooling channels is enclosed within the lateral footprint occupied by the reticulated heating elements.

[0156] 18. The sprinkler head assembly of example 16, wherein the thermal isolation film comprises a polymer film.

[0157] 19. The sprinkler head assembly of example 18, wherein the polymer film comprises polyetheretherketone (PEEK).

[0158] 20. The sprinkler head assembly of example 19, wherein the polymer film has a thickness between 0.020 inches and 0.040 inches.

[0159] Although the present invention has been described herein with reference to specific embodiments, these embodiments are not intended to limit the present invention and are set forth for exemplary purposes. 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 present invention.

[0160] Such simple modifications and improvements to the various embodiments disclosed herein are within the scope of the disclosed technology, and the specific scope of the disclosed technology will be further defined by the appended claims.

[0161] In the foregoing, it will be apparent that any feature of any of the embodiments may be combined with or substituted for any other feature of any of the other embodiments.

[0162] Unless the context clearly requires otherwise, throughout this specification and claims, the words "include", "comprises", "contains", "have", etc. should be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to". As generally used herein, the word "coupled" refers to two or more elements that can be connected directly or by means of one or more intermediate elements. Similarly, as generally used herein, the word "connected" refers to two or more elements that can be connected directly or by means of one or more intermediate elements. In addition, the words "herein", "above", "below" and words of similar meanings when used in this application should refer to the entirety of this application, and not to any particular part of this application. Where the context permits, the words used in the singular or plural in the above specific embodiments may also include the plural or singular, respectively. The word "or" when referring to a list of two or more items, the word covers all the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list.

[0163] Furthermore, conditional language used herein, particularly words such as "can," "may," "might," "could," "for example," "for example," "such as," and the like, unless specifically stated otherwise or understood otherwise in the context as used, are generally intended to convey that certain embodiments include, while other embodiments do not, certain features, elements, and / or states. Thus, such conditional language is generally not intended to imply that one or more embodiments in any way require features, elements, and / or states, or whether such features, elements, and / or states are included or are to be performed in any particular embodiment.

[0164] Although specific embodiments have been described, these embodiments are presented only by way of example and are not intended to limit the scope of the present disclosure. In fact, the novel devices, methods, and systems described herein may be embodied in a variety of other forms; in addition, various omissions, substitutions, and changes may be made to the forms of the methods and systems described herein without departing from the spirit of the present disclosure. For example, although features are presented in a given arrangement, alternative embodiments may perform similar functionality with different components and / or sensor topologies, and may delete, move, add, subdivide, combine, and / or modify some features. Each of these features may be implemented in a variety of different ways. Any suitable combination of the elements and actions of the various embodiments described above may be combined to provide additional embodiments. The various features and processes described above may be implemented independently of one another, or may be combined in various ways. All possible combinations and subcombinations of the features of the present disclosure are intended to fall within the scope of the present disclosure.

Claims

1. A temperature controlled showerhead assembly configured to deliver a plurality of gases into a circulating deposition chamber, the showerhead assembly comprising: a showerhead body including a cavity formed therethrough and at a central region of the showerhead body, wherein the cavity is configured to diffuse or mix the gas prior to introducing the gas into the deposition chamber; a reticulated cooling channel configured to conduct heat away from the showerhead body; and A heating element in a mesh structure is configured to supply heat to the sprinkler head body, wherein the heating element in a mesh structure is disposed closer to an upper surface of the sprinkler head body than the cooling channel.

2. The sprinkler head assembly according to claim 1, wherein: The cooling channels and the heating elements in a mesh structure are arranged at different vertical heights.

3. The sprinkler head assembly according to claim 2, wherein: The cooling channel and the reticulated heating element are thermally insulated from each other by an insulating layer disposed between the cooling channel and the reticulated heating element.

4. The sprinkler head assembly according to claim 3, wherein: The cooling channels and the reticulated structure of the heating elements laterally surround the cavity.

5. The sprinkler head assembly according to claim 4, wherein: The cavity has a truncated cone shape that is elongated in a vertical direction, and has a width that increases in a direction toward a base disposed below the sprinkler head assembly.

6. The sprinkler head assembly of claim 1, wherein: The sprinkler head assembly further includes an injector block disposed above the sprinkler head body, wherein the injector block includes a plurality of channels formed therein, the plurality of channels being used to flow different gases to direct the different gases into the cavity in different directions.

7. The sprinkler head assembly of claim 6, wherein: The chamber is configured to mix the two different gases prior to introducing the two different gases into the deposition chamber.

8. The sprinkler head assembly of claim 7, wherein: One of the two different gases is an inert gas, and the other of the two different gases is a reactant.

9. A temperature controlled showerhead assembly configured to deliver a plurality of gases into a circulating deposition chamber, the showerhead assembly comprising: a sprinkler head body having a generally flat outer surface facing away from the base, and an inner surface facing the base, the inner surface being tapered such that a thickness of the sprinkler head body increases from a central region toward an edge portion of the sprinkler head body; a cavity formed through the showerhead body at the central region and configured to diffuse or mix the gas prior to introducing the gas into the deposition chamber; as well as A cooling channel in a reticulated structure and a heating element in a reticulated structure, wherein the cooling channel in a reticulated structure and the heating element in a reticulated structure are formed at different vertical heights.

10. The sprinkler head assembly of claim 9, wherein: The reticulated cooling channels and the reticulated heating elements are configured such that, during deposition, the inner surface of the showerhead body is maintained at a temperature at least 20° C. higher than a temperature of a liquid coolant filling the cooling channels.

11. The sprinkler head assembly of claim 9, wherein: The cooling channel and the heating element in a mesh structure are thermally insulated from each other by a thermal insulation film vertically disposed between the cooling channel and the heating element in a mesh structure.

12. The sprinkler head assembly of claim 9, wherein: The sprinkler head assembly also includes a plurality of thermal couplings disposed within 0.5 inches of the inner surface of the sprinkler head body that faces the base.

13. The sprinkler head assembly of claim 9, wherein: The outer surface of the sprinkler head body is inclined in a radial direction to have a neck angle of less than 10 degrees relative to a horizontal direction.

14. The sprinkler head assembly of claim 9, wherein: The cavity is a tapered cavity, and the tapered cavity has a side wall of the tapered cavity having a tapered angle less than 10 degrees relative to a vertical direction.

15. The sprinkler head assembly of claim 9, wherein: The distance between the bottommost surface of the sprinkler head body facing the base and the upper surface of the base is less than 0.3".

16. A temperature controlled showerhead assembly configured to deliver a plurality of gases into a circulating deposition chamber, the showerhead assembly comprising: a showerhead body including a cavity formed therethrough and at a central region of the showerhead body, wherein the cavity is configured to diffuse or mix the gas prior to introducing the gas into the deposition chamber; A cooling channel in a mesh structure, wherein the cooling channel in a mesh structure is formed above the sprinkler head body and is configured to conduct heat away from the sprinkler head; a heating element in a reticulated structure, the heating element in a reticulated structure being configured to supply heat to the sprinkler head; and A heat insulating film is vertically arranged between the cooling channel and the heating element in a mesh structure.

17. The sprinkler head assembly of claim 16, wherein: The lateral coverage area occupied by the reticulated cooling channels is enclosed within the lateral coverage area occupied by the reticulated heating elements.

18. The sprinkler head assembly of claim 16, wherein: The heat insulating film includes a polymer film.

19. The sprinkler head assembly of claim 18, wherein: The polymer film includes polyetheretherketone (PEEK).

20. The sprinkler head assembly of claim 19, wherein: The polymer film has a thickness between 0.020 inches and 0.040 inches.

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