Metal film deposition

Abstract

A low resistance metallization stack structure and associated fabrication methods are provided for logic and memory applications. In some embodiments, a thin metal oxynitride or metal nitride nucleation layer is deposited, followed by the deposition of a pure metal conductor. The nucleation layer is amorphous and serves as a template for large pure metal film grain growth and low resistivity. Additionally, certain embodiments of the method described below convert most or all of the metal oxynitride nucleation layer to a pure metal layer, further reducing resistivity.

Description

[Background technology]

[0001] [Incorporated by reference] A PCT Request Form is being filed contemporaneously herewith as part of this application. Each application to which this application claims benefit or priority as identified in the contemporaneously filed PCT Request Form is incorporated herein by reference in its entirety for all purposes.

[0002] Tungsten (W) film deposition using chemical vapor deposition (CVD) techniques is an essential part of semiconductor manufacturing processes. For example, tungsten films can be used as low-resistance electrical connections in the form of horizontal interconnects, vias between adjacent metal layers, and contacts between the first metal layer and devices on silicon substrates. Tungsten films can also be used in various memory applications (e.g., buried wordline (bWL) architectures for dynamic random access memory (DRAM) and wordline formation for 3D NAND) and logic applications. However, the ever-decreasing feature sizes and film thicknesses pose various challenges, including high resistivity in thinner films. Other metals, such as molybdenum (Mo), are being evaluated as low-resistivity alternatives to W.

[0003] The background art provided herein is intended to provide a general background to the present disclosure, and the work of the inventors named herein, to the extent described in this background art, along with aspects of the description that would not normally be considered prior art at the time of filing, are not admitted expressly or impliedly as prior art to the present disclosure. Summary of the Invention

[0004] One aspect of the present disclosure relates to a method for depositing a metal, the method comprising depositing a first layer from a metal oxychloride precursor and ammonia using a first atomic layer deposition (ALD) process, the method further comprising depositing an elemental metal layer on the first layer from the metal oxychloride precursor and hydrogen using a second ALD process.

[0005] Embodiments may include one or more of the following features: In the method, the first layer is a metal oxynitride layer or a metal nitride layer. In the method, the first layer is converted to an elemental metal layer during or before the second ALD process. In the method, the elemental metal layer after conversion contains less than 1 atomic % impurities. In the method, the first layer is an amorphous layer. In the method, the elemental layer is crystalline. In the method, the first and second ALD processes are performed in the same chamber without exposure to air. In the method, the first layer is a template for metal grain growth in the second layer. In the method, the elemental layer contains less than 1 atomic % impurities. In the method, the elemental metal layer is elemental tungsten. In the method, the elemental metal layer is elemental molybdenum. In the method, the first layer is one of molybdenum oxynitride and molybdenum nitride. In the method, the first ALD process is performed at a temperature below 400°C. In the method, the second ALD process is performed at a temperature greater than 400°C. In the method, deposition of the first layer and deposition of the elemental layer are performed in the same chamber. In the method, deposition of the first layer and deposition of the elemental layer are performed in different stations of the same chamber. In the method, deposition of the first layer is performed in the first chamber and deposition of the elemental layer is performed in the second chamber. The method further comprises exposing the first layer to air prior to deposition of the elemental layer.

[0006] Another aspect of the present disclosure relates to an apparatus comprising first and second process chambers each configured to accommodate a substrate, a substrate support in each of the process chambers, a gas inlet configured to direct gas into each of the process chambers, a heater configured to heat the substrate support in each process chamber, and a controller with program instructions. The apparatus further includes sequentially flowing a metal oxychloride precursor and ammonia into the first process chamber while the substrate is accommodated in the first process chamber. The apparatus further includes, after (a), transferring the substrate to a second process chamber. The apparatus further includes, after (b), sequentially flowing the metal oxychloride precursor and hydrogen into the second process chamber while the substrate is accommodated in the second process chamber.

[0007] Another aspect of the present disclosure relates to an apparatus comprising: a processing chamber having one or more stations each configured to accommodate a substrate; a substrate support in each of the one or more stations; a gas inlet configured to direct gas into each of the one or more stations; a heater configured to heat the substrate support in each station; and a controller, the controller comprising program instructions for sequentially flowing a metal oxychloride precursor and ammonia into one of the one or more stations; and program instructions for sequentially flowing the metal oxychloride precursor and hydrogen into one of the one or more stations.

[0008] These and other aspects are described more fully below with reference to the drawings. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1 shows a schematic example of a material stack including a nucleation layer as a template for metal growth. [Figure 1B] FIG. 1 shows a schematic example of a material stack including a nucleation layer as a template for metal growth.

[0010] [Figure 2] 1A-1C provide examples of structures in which material stacks may be utilized, according to embodiments. [Figure 3A] 1A-1C provide examples of structures in which material stacks may be utilized, according to embodiments. [Figure 3B] 1A-1C provide examples of structures in which material stacks may be utilized, according to embodiments.

[0011] [Figure 4] 1 is a process flow diagram illustrating steps in a method for depositing conductive material, according to various embodiments.

[0012] [Figure 5] FIG. 1 shows the growth rate of atomic layer deposition of molybdenum-containing layers on dielectric surfaces using an ammonia reducing agent and a molybdenum oxychloride precursor.

[0013] [Figure 6] FIG. 1 illustrates molybdenum growth from hydrogen and molybdenum oxychloride onto a nucleation layer deposited on a dielectric surface as described herein, compared to molybdenum growth from hydrogen and molybdenum oxychloride directly onto the dielectric surface.

[0014] [Figure 7] 2 is a graph showing the resistivity of a molybdenum film deposited as described herein compared to a molybdenum film deposited on titanium nitride.

[0015] [Figure 8] FIG. 1 is a block diagram illustrating a processing system suitable for performing deposition processes in accordance with embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0016] In the following description, numerous specific details are set forth to provide a thorough understanding of the presented embodiments. The disclosed embodiments may be practiced without some or all of these specific details. Additionally, detailed descriptions of well-known process operations are omitted to avoid unnecessarily obscuring the disclosed embodiments. While the disclosed embodiments are described in connection with specific embodiments, it should be understood that they are not intended to limit the disclosed embodiments.

[0017] Provided herein are low-resistivity metallization stack structures and associated fabrication methods for logic and memory applications. In some embodiments, a thin metal oxynitride or metal nitride nucleation layer is deposited, followed by the deposition of a pure metal conductor. The nucleation layer is amorphous, providing a template for large pure metal film grain growth and low resistivity. Additionally, certain embodiments of the methods described below convert most or all of the metal oxynitride nucleation layer to a pure metal layer, further reducing resistivity.

[0018] According to various embodiments, one or more advantages may be realized. In some embodiments, deposition of metals (such as Mo) directly onto aluminum oxide and other dielectrics may be performed. In some embodiments, these depositions may be performed at temperatures below 500°C or even below 400°C without significant nucleation delay. Deposition at lower temperatures may lead to better step coverage. In various embodiments, lower resistivity films may be obtained from larger grain sizes and / or films may be deposited directly onto dielectrics without a high-resistivity film such as titanium nitride (TiN). The addition of a low-temperature metal nitride nucleation layer may enable subsequent pure metal deposition at temperatures below 600°C or even below 500°C. This may make the metal (nitride) + pure metal nucleation stack suitable for semiconductor applications that have thermal budgets below 600°C or 500°C for wafer processing. This allows deposition of metals at temperatures inaccessible to pure films without a high-resistivity layer such as TiN. For example, temperatures for ALD of pure Mo can exceed 600° C. when deposited directly onto a dielectric.

[0019] 1A and 1B are schematic examples of material stacks including a nucleation layer as a template for metal growth. FIGS. 1A and 1B illustrate the order of materials in a particular stack, which may be used in any suitable architecture and application, as described in more detail below with respect to FIGS. 2, 3A, and 3B. In the example of FIG. 1A, a substrate 102 has a nucleation layer 108 deposited thereon. The substrate 102 may be a silicon or other semiconductor wafer, e.g., a 200 mm wafer, a 300 mm wafer, or a 450 mm wafer, and may include a wafer having one or more material layers deposited thereon, such as a dielectric material, a conductive material, or a semiconductor material. The method may also be applied to form metallization stack structures on other substrates (e.g., glass, plastic, etc.).

[0020] In FIG. 1A, a dielectric layer 104 overlies a substrate 102. The dielectric layer 104 may be deposited directly on the semiconductor (e.g., Si) surface of the substrate 102, or any number of intermediate layers may be present. Examples of dielectric layers include doped and undoped silicon oxide, silicon nitride, and aluminum oxide layers, with specific examples being doped or undoped layers of SiO2 and Al2O3. Also in FIG. 1A, a diffusion barrier layer 106 is disposed between a nucleation layer 108 and the dielectric layer 104. Examples of diffusion barrier layers include titanium nitride (TiN), titanium / titanium nitride (Ti / TiN), tungsten nitride (WN), and tungsten carbonitride (WCN). A metal layer 110 is deposited on the nucleation layer 108 and is the main conductor (also referred to as the bulk conductor or bulk layer) of the structure, with the nucleation layer 108 providing a template for metal growth.

[0021] As will be described in more detail below, the nucleation layer 108 is deposited as an amorphous film. By using the large-grained amorphous film as a template for metal growth, large-grained, low-resistivity metals can be formed. Examples of metal layers include tungsten (W) and molybdenum (Mo) layers.

[0022] 1B shows another example of a material stack. In this example, the stack comprises a substrate 102, a dielectric layer 104, and a nucleation layer 108 deposited directly on the dielectric layer 104, with no diffusion barrier layer in between. As in the example of FIG. 1A, a metal layer 110 is deposited on the nucleation layer 108 and is the main conductor of the structure.

[0023] 1A and 1B, nucleation layer 108 may be deposited as a metal oxynitride layer (e.g., a layer of tungsten oxynitride or molybdenum oxynitride). However, during subsequent processing, in certain embodiments, all or most of nucleation layer 108 may be converted to pure metal. Thus, according to various embodiments, nucleation layer 108 may or may not be of the same composition as pure metal layer 110. Nucleation layer 108 may be characterized by amorphous nature, and pure metal layer 110 may be characterized by a large grain size.

[0024] In some embodiments, the metal of the metal oxynitride layer is the same as the metal of the pure metal conductor, e.g., a molybdenum oxynitride layer may be deposited as a nucleation layer before the deposition of a molybdenum layer, and a tungsten oxynitride layer may be deposited as a nucleation layer before the deposition of a tungsten layer. In other embodiments, the metal oxynitride layer may have a different metal than the metal of the pure metal conductor, e.g., a tungsten layer may be deposited on a molybdenum-containing nucleation layer, and a molybdenum layer may be deposited on a tungsten-containing nucleation layer.

[0025] 1A and 1B illustrate example metallization stacks, the methods and resulting stacks are not so limited. For example, in some embodiments, a nucleation layer may be deposited directly on a Si or other semiconductor substrate as a template for metal growth. Furthermore, while the growth of tungsten (W) or molybdenum (Mo) on a nucleation layer is described above, the nucleation layer may also serve as a template for the low-resistivity growth of other metals (e.g., cobalt (Co), ruthenium (Ru), nickel (Ni)), and alloys containing these metals (e.g., MoW). Furthermore, the nucleation layer may be a layer of any suitable metal oxynitride or metal nitride, such as molybdenum oxynitride, molybdenum nitride, tungsten oxynitride, tungsten nitride, or nickel nitride.

[0026] The material stacks described above and further below may be implemented in a variety of structures. FIGS. 2, 3A, and 3B provide examples of structures in which the stacks may be utilized. FIG. 2 shows a schematic example of a DRAM architecture with a buried word line (bWL) 210 in a silicon substrate 202. The bWL 210 is formed in a trench etched in the silicon substrate 202. Lining the trench is a conformal nucleation layer 208 and an insulating layer 204 disposed between the conformal nucleation layer 208 and the silicon substrate 202. In the example of FIG. 2, the insulating layer 204 may be a gate oxide layer formed from a high-k material (such as a silicon oxide or silicon nitride material). In some embodiments, a conformal barrier layer, such as TiN or a tungsten-containing layer, may be sandwiched between the nucleation layer 208 and the insulating layer 204.

[0027] FIG. 3A shows a schematic example of word lines 310 in a 3D NAND structure 323. The word lines 310 are separated by oxide layers 311. In FIG. 3B, details of the interface between the word lines 310 and the oxide layer 311 are shown, including an aluminum oxide (Al2O3) layer 304 and a nucleation layer 308. In some embodiments, the nucleation layer 308 may be deposited directly on the oxide layer 311 or on a TiN or other barrier layer, as described herein. The nucleation layer may be, for example, between about 10 Å and 100 Å, or between 10 Å and 50 Å, for deposition of word lines 310 between about 10 nm and 100 nm thick.

[0028] 4 is a process flow diagram illustrating steps in a method for depositing a conductive material. In step 402, a conformal nucleation layer is formed on a structure by atomic layer deposition (ALD). In an ALD process, a substrate is exposed in cycles such that the substrate is first exposed to a pulse of an appropriate metal-containing precursor, the precursor is then optionally purged, the substrate is then exposed to a pulse of a reducing agent, and the reducing agent is then optionally purged; such cycles may be repeated until a nucleation layer of the desired thickness is formed for the substrate. It is understood that the order of precursor and reducing agent may be reversed, such that the sequence begins with a reducing agent dose followed by a metal-containing precursor dose.

[0029] In some embodiments, the reducing agent is ammonia (NH) or other nitrogen-containing reducing agent, such as hydrazine (NH). NH chemisorption to dielectrics is more favorable than hydrogen (H). In some embodiments, the reducing agent and precursor are selected to react without dissociation of the reducing agent. NH reacts with metal oxychlorides and metal chlorides without dissociation. This contrasts with, for example, ALD from metal oxychlorides using H as the reducing agent, where H dissociates on the surface to form adatom hydrogen, resulting in very low concentrations of reactive species and low surface coverage during the initial nucleation of the metal on the dielectric surface. Using NH and a metal oxychloride or metal chloride precursor reduces or eliminates nucleation delays at deposition temperatures up to several hundred degrees lower than those used by H reduction of the same metal precursor.

[0030] In some embodiments, the reducing agent can be a boron- or silicon-containing reducing agent, such as diborane (B2H6) or (SiH4). These reducing agents can be used with metal chloride precursors or with metal oxychlorides; however, B2H6 and SiH4 react with water formed as a by-product during the ALD process to form B2O3 and SiO2, which are insulating and remain in the film, increasing resistivity. The use of NH3 also improves adhesion to certain surfaces, including Al2O3, compared to ALD with B2H6 and SiH4.

[0031] Examples of metal oxychlorides and metal chloride precursors include molybdenum pentachloride (MoCl), molybdenum oxychlorides (such as molybdenum dichloride dioxide (MoOCl) and molybdenum tetrachloride (MoOCl)), tungsten pentachloride (WC1), tungsten hexachloride (WC1), tungsten tetrachloride (WC1), tungsten dichloride (WC1), and tungsten oxychloride (WOC1). x Cl y ) (such as tungsten oxide tetrachloride (WOCl4)).

[0032] Metal chlorides and metal oxychlorides may be useful in embodiments where fluorine contamination is a concern. However, in some embodiments, fluorine-containing precursors may be used. These include metal fluorides such as tungsten hexafluoride (WF), molybdenum hexafluoride (MoF), and molybdenum pentafluoride (MoF).

[0033] The resulting nucleation layer is generally a metal nitride or metal oxynitride film rather than a pure elemental film. In some embodiments, residual chlorine or fluorine from deposition may be present, especially when deposition is performed at low temperatures. In some embodiments, the residual chlorine or fluorine is only trace amounts. In some embodiments, the nucleation layer is an amorphous layer. Impurities in the film (e.g., oxygen, NH3, chlorine, or other halogens) promote the growth of an amorphous microstructure. In some embodiments, the as-deposited nucleation layer is an amorphous metal oxynitride or metal nitride layer. The amorphous nature provides a template for large grain growth in the subsequently deposited conductor. The surface energy of nitrides or oxynitrides relative to oxide surfaces is much more favorable than that of metals on oxide surfaces, facilitating the formation of continuous and smooth films on dielectrics. This allows for the formation of thin, continuous layers. Example thicknesses of nucleation films range from 5 to 30 Å as deposited. Depending on the temperature, this can be, for example, about 5 to 50 ALD cycles.

[0034] As will be described below, during subsequent processing, the nucleation layer may be converted to a pure (or less impure) elemental metal film and reduced in thickness.

[0035] Substrate temperatures for nucleation layer deposition may range, for example, from 300°C to 600°C. In some embodiments, lower temperatures may be used. Such temperatures may be less than 500°C, less than 550°C, less than 450°C, less than 400°C, or less than 350°C. Lower temperatures may be used to improve step coverage. Additionally, lower temperatures may increase the amount of impurities in the nucleation layer, increasing amorphousness, which in turn may increase the grain size of the subsequently deposited conductor.

[0036] The surface onto which the nucleation layer is deposited will depend on the particular application. In some embodiments, the nucleation layer is deposited directly onto a dielectric (e.g., silicon oxide, aluminum oxide, silicon nitride, etc.) surface. In some embodiments, the nucleation layer is deposited directly onto a titanium nitride or other surface. Subsequent elemental metal deposition may be performed on any surface by performing step 402, as described in more detail below.

[0037] After deposition of the nucleation layer, optional step 404 may be performed, in which a lower temperature ALD cycle of metal conductor and reducing agent is performed. By "lower" temperature, it is meant that the temperature of step 404, if performed, is lower than that of the subsequent step 406. Examples of temperatures include temperatures below 500°C, below 550°C, below 450°C, below 400°C, or below 350°C. In this step, the reducing agent is different from that of step 402, and a particular example of such a reducing agent is hydrogen (H). In particular, H can lead to the deposition of an elemental film with significantly fewer impurities than the nucleation layer. In some embodiments, the temperature can be the same as that used in step 402. Also, the metal precursor can be the same or a different precursor from that used in step 402. In some embodiments, the same precursor is used, and only the reducing agent is changed. In some embodiments, step 404 can facilitate the conversion of the metal nitride or metal oxynitride nucleation layer to an elemental metal film. According to various embodiments, step 404 may or may not deposit a significant amount of a main conductor film.

[0038] In a further optional step 406, the substrate temperature is increased. In embodiments in which step 404 is performed, step 406 is also performed. In other embodiments, operation 406 may be performed. For example, if the nucleation layer deposition was performed at a relatively low temperature (e.g., less than 400°C), the temperature may be increased in operation 406 to a higher temperature at which the main conductor deposition is performed. In some embodiments, the temperature may be greater than 500°C, and in some embodiments, greater than 600°C. In some embodiments, a lower temperature (e.g., between 400°C and 500°C, inclusive) may be used for the bulk deposition. The temperature may or may not be increased depending on the temperature of the previous step.

[0039] The method may then proceed to step 408 (from either step 402, 404, or 406) where the main conductor is deposited by ALD. As in step 404 (if performed), H may be used as the reducing agent.

[0040] Examples of metal oxychlorides and metal chloride precursors that may be used in steps 404 and 408 include molybdenum pentachloride (MoCl5) and molybdenum hexachloride (MoCl6), molybdenum oxychlorides (such as molybdenum dichloride dioxide (MoOCl2) and molybdenum tetrachloride (MoOCl4)), tungsten pentachloride (WC15), tungsten hexachloride (WC16), tungsten tetrachloride (WC14), tungsten dichloride (WC12), and tungsten oxychloride (WOC15). x Cl y ) (such as tungsten oxide tetrachloride (WOCl4)).

[0041] During one or more of steps 404-408, the nucleation layer is converted to an elemental metal layer. This may also be characterized as the removal of impurities (i.e., any non-metallic components). While the nucleation layer may have more impurities than the subsequently deposited elemental layer, the impurities are sufficiently removed so that the resistivity of the stack is the same or comparable to a stack without the nucleation layer. The thickness is also reduced; for example, a 30 Å as-deposited film may contribute approximately 10 Å of metal to the stack.

[0042] According to various embodiments, one or more of the following may be used to facilitate the conversion of the nucleation layer to an elemental metal film: 1) depositing the bulk conductor at a higher temperature (e.g., 550°C) than the nucleation layer is deposited at; 2) performing a lower temperature ALD H / metal precursor cycle as described with reference to step 404 above; and 3) in-situ deposition of the bulk layer such that the nucleation layer is not exposed to air or otherwise oxidized prior to bulk deposition. Mo oxychlorides and W oxychlorides, in particular, are relatively easy to convert to elemental metals. The resulting converted nucleation layer and pure metal layer may each be characterized as having 1% or less atomic impurities.

[0043] Figure 5 shows the results of forming a Mo-containing layer using NH3 reducing agent and a molybdenum oxychloride precursor to form a nucleation layer, followed by conversion of the Mo-containing layer to Mo as described above. Figure 5 shows the thickness of the nucleation layer after conversion to Mo as a function of ALD cycles. Deposition was performed on three different surfaces (Al2O3, TiN, and thermal SiO2) at each temperature (350°C—low temperature, 400°C—medium temperature, and 450°C—high temperature). At each temperature, the growth rate is the same on all surfaces. Therefore, the growth rate is independent of temperature and the substrate surface. This is particularly different from other deposition systems, which can be very substrate-dependent. For example, ALD deposition with H2 and molybdenum oxychloride deposits a small amount on TiN, a small amount on SiO2, and almost nothing on Al2O3.

[0044] Figure 6 shows Mo growth from an ALD cycle of H and molybdenum oxychloride directly on an AlO surface at 550 °C, followed by subsequent Mo growth on a nucleation layer deposited on the AlO surface as described above. Curve A shows Mo growth on a nucleation layer of approximately 10 Å deposited from NH / Mo oxychloride, while curve B shows Mo growth on AlO. As can be seen, ALD deposition from H reduction of the Mo precursor shows stable growth on the Mo nucleation layer deposited from NH reduction of the Mo precursor, with no nucleation delay. In contrast, ALD cycles with H / Mo precursor result in no deposition on AlO.

[0045] Figure 7 shows the resistivity of various Mo films. Curve A shows the resistivity of an H / Mo oxychloride ALD film on a low-temperature NH / Mo oxychloride nucleation layer, curve B shows the resistivity of an H / Mo oxychloride ALD film on a high-temperature NH / Mo oxychloride nucleation layer, and curve C shows the resistivity of an H / Mo oxychloride ALD film on TiN. Using the nucleation layer described herein, no increase in blanket resistivity is observed, suggesting that the nucleation layer is converted to an elemental Mo film.

[0046] Although the above description refers to metal oxychloride and metal chloride precursors, the method may be practiced with other halogen-containing precursors, such as metal oxyfluoride and metal fluoride precursors.

[0047] In some embodiments, the method may comprise depositing a metal oxynitride or metal nitride nucleation layer followed by deposition of a pure metal layer by chemical vapor deposition (CVD).

[0048] Device Any suitable chamber can be used to practice the disclosed embodiments. Examples of deposition apparatus include various systems, such as the ALTUS® and ALTUS® Max manufactured by Lam Research, Inc., Fremont, Calif., or any of a variety of other commercially available processing systems. Processing can be performed in parallel at multiple deposition stations.

[0049] In some embodiments, the nucleation layer deposition process is performed in a first station, which is one of two, five, or even more deposition stations arranged within a single deposition chamber. For example, nucleation layer deposition is performed in the first station, followed by low-temperature hydrogen reduction of the metal precursor in the second station, and then high-temperature hydrogen reduction of the metal precursor in the third station. Each station may have independent temperature control. In some embodiments, various steps of the process are performed in two different stations of the deposition chamber. For example, the substrate may be exposed to NH3 in the first station using individual gas supply systems to create a local atmosphere at the substrate surface, and then the substrate is transferred to the second station and exposed to a metal chloride, metal fluoride, or metal oxychloride precursor to deposit the nucleation layer. In some embodiments, the substrate may then be returned to the first station for a second exposure to NH3. The substrate may then be transferred to the second station for exposure to the metal precursor. The substrate may be exposed to NH3 in a separate station after deposition of the first metal chloride or metal oxychloride. This may be repeated as necessary to complete the nucleation layer deposition and proceed with bulk layer deposition at the same or a different station.

[0050] In some embodiments, multiple chambers are used to perform the methods described herein. For example, deposition of a nucleation layer may be performed in a first chamber, and deposition of a bulk metal layer may be performed in a second chamber. The two chambers may be connected to a common vacuum chamber so that substrates can be transferred between them without exposure. In other embodiments, the chambers are not connected under vacuum, and the substrates are exposed to air during transfer. Any oxidation can be reduced in subsequent processing, as described above.

[0051] FIG. 8 is a block diagram illustrating a processing system suitable for performing deposition processes in accordance with embodiments described herein. System 800 includes a transfer module 803. Transfer module 803 provides a clean, pressurized environment to minimize the risk of contamination when substrates undergoing processing are moved between various reactor modules. Mounted on transfer module 803 is a multi-station reactor 809 capable of performing ALD deposition as described herein. Chamber 809 may include multiple stations 811, 813, 815, and 817 that may sequentially perform these operations. For example, chamber 809 may be configured such that stations 811 and 813 perform nucleation layer deposition, and stations 813 and 815 perform bulk layer deposition. Each deposition station may include a heated wafer pedestal and a showerhead, diffuser plate, or other gas inlet.

[0052] One or more single-station or multi-station modules 807 capable of performing plasma pre-cleaning or chemical (non-plasma) pre-cleaning may also be mounted on the transfer module 803. Modules may also be used for various other processes (e.g., reducing agent soaks). The system 800 also includes one or more (two in this example) wafer source modules 801 where wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 819 first removes wafers from the source modules 801 to a load lock 821. A wafer transfer device (typically a robot arm unit) in the transfer module 803 moves wafers from the load lock 821 to and between modules mounted on the transfer module 803.

[0053] In some embodiments, a high-temperature showerhead is used. This allows for the use of a single-plenum showerhead rather than a dual one. By maintaining the wetted surfaces inside the showerhead at temperatures above 150°C or 200°C, NH3 and metal oxynitride or metal chloride precursors can be used in a single-plenum showerhead without condensation of NH4Cl. Alternatively, a dual-plenum showerhead can be used in which NH3 is supplied through one plenum and metal chloride or metal oxychloride precursors can be supplied through the other plenum.

[0054] As mentioned above, in some embodiments, depositing both metal (nitride) nucleation and pure metal in a single process chamber involves the use of H, metal (acid chlorides), and their by-products (HCl, OCl). x , metal-Cl x As-deposited metal + O by high-temperature reaction with x +NH x +Cl xThis facilitates the conversion of the nucleation film of the metal to pure metal. This can be done in a multi-station reactor using a low temperature in the first deposition station and a high temperature in subsequent deposition stations, as described above. In some embodiments, the individual deposition stations in a multi-station deposition reactor can be separated from each other by shaping the showerhead and pedestal so that, in the pedestal-raised processing position, the two assemblies form a small processing space above the wafer and a very narrow gap separating the processing space from the main chamber. The narrow gap at the edge of the processing space can be reinforced with an inert gas purge barrier to make it difficult for gases to diffuse from the main chamber into the processing space. The narrow gap at the edge of the processing space can also incorporate a localized pumping plenum to prevent processing gases from entering the main chamber. This can eliminate the risk of deposition or particle generation occurring in the main chamber. The narrow edge gap itself can eliminate the risk of gases from the main chamber diffusing back into the wafer processing space, ensuring no interference between stations.

[0055] As mentioned above, in certain embodiments, the system includes two different deposition chambers. For example, referring to FIG. 8, two deposition chambers may be mounted on transfer module 803. In such embodiments, each deposition chamber may be a single or multi-station chamber. Furthermore, two chambers that are not under a common vacuum may be used.

[0056] In certain embodiments, a system controller 829 is used to control process conditions during deposition. The controller typically includes one or more memory devices and one or more processors. The processor may include a CPU or computer, analog and / or digital input / output connections, stepper motor controller boards, etc.

[0057] The controller may control all operations of the deposition apparatus. The system controller executes system control software that includes a set of instructions for controlling the timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, if used, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored on memory devices associated with the controller may also be used in some embodiments.

[0058] Typically, there is a user interface associated with the controller, which may include a display screen (graphical software display of equipment and / or process conditions) and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

[0059] System control logic may be configured in any suitable manner. In general, logic may be designed or configured in hardware and / or software. Instructions for controlling the drive circuitry may be hard-coded or provided as software. Instructions may be provided by "programming." Such programming is understood to include any form of logic, such as logic hard-coded in digital signal processors, application-specific integrated circuits, and other devices with specific algorithms implemented as hardware. Programming is also understood to include software or firmware instructions executable on a general-purpose processor. System control software may be coded in any suitable computer-readable programming language. Alternatively, the control logic may be hard-coded into the controller. For these purposes, application-specific integrated circuits, programmable logic devices (e.g., field-programmable gate arrays, or FPGAs), etc. may be used. Hereinafter, where "software" or "code" is used, functionally equivalent hard-coded logic may be used instead.

[0060] Computer program code for controlling deposition and other processes in a process flow can be written in any conventional computer-readable programming language, for example, assembly language, C, C++, Pascal, Fortran, etc. The compiled object code or script is executed by a processor to perform the tasks specified in the program.

[0061] The controller parameters relate to process conditions such as process gas composition and flow rate, temperature, pressure, cooling gas pressure, and chamber wall temperature, etc. These parameters are provided to the user in the form of a recipe and can be entered using a user interface.

[0062] Signals for monitoring the process may be provided by analog and / or digital input connections of the system controller, and signals for controlling the process are output at analog and digital output connections of the deposition apparatus.

[0063] The system software can be designed or configured in many different ways. For example, various chamber component subroutines or control objects may be written to control the operation of the chamber components necessary to perform the deposition processes described herein. Examples of programs or program sections for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0064] In some embodiments, the controller 829 is part of a system, which may be part of the examples described above. Such systems may include semiconductor processing equipment, such as one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (e.g., wafer pedestals, gas flow systems, etc.). These systems may be integrated with electronics for controlling the operation of the system before, during, and after processing of semiconductor wafers or substrates. The electronics may be referred to as a “controller” and may control various components or subcomponents of the system. Depending on the processing requirements and / or type of system, the controller 829 may be programmed to control any of the processes disclosed herein, such as supply of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, RF matching circuit settings, frequency settings, flow rate settings, fluid supply settings, position and motion settings, and wafer movement in and out of tools and other transfer tools and / or load locks connected or coupled to a particular system.

[0065] Generally, a controller may be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. Integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application-specific integrated circuits (ASICs), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). Program instructions may be communicated to the controller in the form of various individual settings (or program files) that define operational parameters for performing a particular process on or for a semiconductor wafer, or instructions for the system. The operational parameters, in some embodiments, may be part of a recipe defined by a process engineer to accomplish one or more process steps during processing of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0066] In some embodiments, the controller 829 may be part of or connected to a computer that is integrated with, connected to, or otherwise networked with the system, or a combination thereof. For example, the controller 829 may be in the “cloud” or may be all or part of a fab host computer system that can enable remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of a manufacturing operation, examine the history of past manufacturing operations, or examine trends or performance indicators from multiple manufacturing operations, to change parameters of a current process, set up processing steps according to a current process, or initiate a new process. In some examples, a remote computer (e.g., a server) may provide process recipes to the system over a network (which may include a local network or the Internet). The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, where the instructions specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process being performed as well as the type of tool the controller is configured to interface with or control. Thus, as described above, the controller may be distributed, such as by having one or more separate controllers that are networked and operate toward a common purpose (such as the process and control described herein). One example of a distributed controller for such purposes is one or more integrated circuits on the chamber that communicate with one or more remotely located integrated circuits (e.g., at the platform level or located as part of a remote computer) that cooperate to control the process in the chamber.

[0067] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a CVD chamber or module, an ALD chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing system that may be associated with or utilized in the fabrication and / or manufacturing of semiconductor wafers.

[0068] As described above, depending on the processing step or steps being performed by the tool, the controller may communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, nearby tools, tools located throughout the factory, a main computer, another controller, or tools used in material transport to carry containers of wafers to or from tool locations and / or load ports within a semiconductor fabrication factory.

[0069] The controller 829 may include various programs. A substrate positioning program may include program code for controlling chamber components used to load a substrate onto the pedestal or chuck and to control the spacing between the substrate and other parts of the chamber (such as the gas inlet and / or gas target). A process gas control program may include code for controlling gas composition and flow rates, and optionally, for flowing gas into the chamber prior to deposition to stabilize the pressure within the chamber. A pressure control program may include code for controlling the pressure within the chamber, for example, by adjusting a throttle valve in the chamber's exhaust system. A heater control program may include code for controlling the current to a heating unit used to heat the substrate. Alternatively, the heater control program may control the supply of a thermally conductive gas (such as helium) to the wafer chuck.

[0070] Examples of chamber sensors that may be monitored during deposition include mass flow controllers, pressure sensors (such as manometers), and thermocouples located in the pedestal or chuck. Appropriately programmed feedback and control algorithms may be used in conjunction with data from these sensors to maintain desired process conditions.

[0071] The implementation of embodiments of the present disclosure in single or multi-chamber semiconductor processing tools has been described above.

[0072] The implementation of the disclosed embodiments in single-chamber or multi-chamber semiconductor processing tools has been described above. The apparatus and processes described herein may be used in conjunction with lithographic patterning tools or processes, for example, for fabricating or manufacturing semiconductor devices, displays, LEDs, photovoltaic panels, etc. Typically, although not necessarily, such tools / processes are utilized or performed together in a common manufacturing facility. Lithographic patterning of thin films typically involves some or all of the following steps, each provided by multiple possible tools: (1) applying photoresist onto a workpiece (i.e., substrate) using a spin-on or spray-on tool; (2) curing the photoresist using a hotplate or furnace or UV curing tool; (3) exposing the photoresist to visible light or UV or X-rays in a tool such as a wafer stepper; (4) developing the resist for patterning by selectively removing the resist using a tool such as a wet bench; (5) transferring the resist pattern to an underlying film or workpiece using a dry etching tool or a plasma-assisted etching tool; and (6) removing the resist using a tool such as an RF plasma or microwave plasma resist stripper.

[0073] In the description above and in the claims, numerical ranges include the endpoints of the range. For example, "a thickness between 1 and 5 nm" includes 1 nm and 5 nm. Similarly, ranges expressed with a prime symbol include the endpoints of the range.

[0074] Conclusion Although the present embodiments have been described in some detail for purposes of clarity, it will be apparent that certain changes and modifications may be made within the scope of the appended claims. It should be noted that there are many other ways of implementing the processes, systems, and apparatus of the present invention. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not limited to the details set forth herein. The present disclosure can also be realized as the following application examples. [Application example 1] 1. A method comprising: depositing a first layer from a metal oxychloride precursor and ammonia using a first atomic layer deposition (ALD) process; depositing an elemental metal layer on the first layer from a metal oxychloride precursor and hydrogen using a second ALD process; A method comprising: [Application example 2] The method according to Application Example 1, wherein the first layer is a metal oxynitride layer or a metal nitride layer. [Application example 3] The method of Application Example 2, wherein the first layer is converted into an elemental metal layer during or before the second ALD process. [Application example 4] The method according to Application Example 3, wherein the converted elemental metal layer contains less than 1 (atomic) % impurities. [Application example 5] The method according to Application Example 1, wherein the first layer is an amorphous layer. [Application Example 6] The method according to Application Example 5, wherein the elemental layer is crystalline. [Application Example 7] The method according to Application Example 1, wherein the first and second ALD processes are performed in the same chamber without exposure to air. [Application Example 8] The method described in Application Example 1, wherein the first layer is a template for metal grain growth in the second layer. [Application Example 9] The method according to Application Example 1, wherein the elemental layer contains less than 1 (atomic) % impurities. [Application Example 10] The method according to Application Example 1, wherein the elemental metal layer is elemental tungsten. [Application Example 11] The method according to Application Example 1, wherein the elemental metal layer is elemental molybdenum. [Application Example 12] The method according to Application Example 1, wherein the first layer is one of molybdenum oxynitride and molybdenum nitride. [Application Example 13] The method according to Application Example 1, wherein the first ALD process is carried out at a temperature lower than 400°C. [Application Example 14] The method according to Application Example 13, wherein the second ALD process is carried out at a temperature higher than 400°C. [Application Example 15] The method according to Application Example 1, wherein the deposition of the first layer and the deposition of the elemental layer are carried out in the same chamber. [Application Example 16] The method according to Application Example 15, wherein the deposition of the first layer and the deposition of the elemental layer are performed in different stations of the same chamber. [Application Example 17] The method according to Application Example 1, wherein deposition of the first layer is performed in a first chamber and deposition of the elemental layer is performed in a second chamber. [Application Example 18] The method according to Application Example 1, further comprising exposing the first layer to air before depositing the elemental layer. [Application Example 19] 1. An apparatus comprising: first and second processing chambers each configured to accommodate a substrate; a substrate support within each of the processing chambers; a gas inlet configured to direct gas into each of the processing chambers; a heater configured to heat the substrate support in each processing chamber; a controller, (a) program instructions for sequentially flowing a metal acid chloride precursor and ammonia into the first processing chamber while a substrate is contained within the first processing chamber; (b) program instructions for transferring the substrate to the second processing chamber after (a); and (c) after (b), a controller having program instructions for sequentially flowing a metal oxychloride precursor and hydrogen into the second processing chamber while the substrate is contained within the second processing chamber; An apparatus comprising: [Application Example 20] 1. An apparatus comprising: a processing chamber having one or more stations each configured to receive a substrate; a substrate support in each of said one or more stations; a gas inlet configured to direct gas into each of the one or more stations; a heater configured to heat the substrate support in each station; a controller, program instructions for sequentially flowing a metal acid chloride precursor and ammonia into one of the one or more stations; and a controller having program instructions for sequentially flowing a metal acid chloride precursor and hydrogen into one of the one or more stations; An apparatus comprising:

Claims

1. 1. A method comprising: forming an elemental molybdenum nucleation layer, the step of forming the elemental molybdenum nucleation layer comprising: forming a molybdenum nitride or oxynitride film as a nucleation layer by exposing a substrate to a molybdenum-containing precursor and a first reducing agent in a reaction chamber, wherein the molybdenum-containing precursor is molybdenum oxychloride or molybdenum chloride, and the first reducing agent comprises a nitrogen-containing reducing agent; converting the nucleation layer to an elemental molybdenum nucleation layer; The substrate was treated with molybdenum oxychloride and hydrogen (H 2 ) forming a bulk layer by exposing the layer to a reducing agent; A method comprising:

2. 10. The method of claim 1, The method wherein the molybdenum-containing precursor is molybdenum oxychloride.

3. 10. The method of claim 1, The molybdenum-containing precursor is molybdenum dioxide dichloride (MoO 2 Cl 2 ) a method.

4. 10. The method of claim 1, The method wherein the nucleation layer is formed using atomic layer deposition (ALD).

5. 10. The method of claim 1, The method wherein the bulk layer is formed by chemical vapor deposition (CVD).

6. 10. The method of claim 1, The method wherein the bulk layer is formed by ALD.

7. 10. The method of claim 1, The molybdenum oxychloride used in forming the bulk layer is molybdenum dioxide dichloride (MoO 2 Cl 2 ) a method.

8. 1. A method comprising: forming a nucleation layer by exposing a substrate to a molybdenum-containing precursor and a first reducing agent in a reaction chamber, wherein the molybdenum-containing precursor is molybdenum oxychloride or molybdenum chloride, and the first reducing agent comprises a nitrogen-containing reducing agent; reducing the thickness of the nucleation layer by removing non-metallic components from the nucleation layer; The substrate was treated with molybdenum oxychloride and hydrogen (H 2 ) forming a bulk layer by exposing the layer to a reducing agent; A method comprising:

9. 9. The method of claim 8, The method wherein the molybdenum-containing precursor is molybdenum oxychloride.

10. 9. The method of claim 8, The molybdenum-containing precursor is molybdenum dioxide dichloride (MoO 2 Cl 2 ) a method.

11. 9. The method of claim 8, The method wherein the nucleation layer is formed using atomic layer deposition (ALD).

12. 9. The method of claim 8, The method wherein the bulk layer is formed by chemical vapor deposition (CVD).

13. 9. The method of claim 8, The method wherein the bulk layer is formed by ALD.

14. 9. The method of claim 8, The molybdenum oxychloride used in forming the bulk layer is molybdenum dioxide dichloride (MoO 2 Cl 2 ) a method.

15. 1. A method comprising: forming a nucleation layer by exposing a substrate to a molybdenum-containing precursor and a first reducing agent in a reaction chamber, wherein the molybdenum-containing precursor is molybdenum oxychloride or molybdenum chloride, and the first reducing agent comprises a nitrogen-containing reducing agent; converting the nucleation layer into an elemental metal layer; The substrate was treated with molybdenum oxychloride and hydrogen (H 2 ) forming a bulk layer by exposing the layer to a reducing agent; A method comprising:

16. 16. The method of claim 15, The method wherein the molybdenum-containing precursor is molybdenum oxychloride.

17. 16. The method of claim 15, The molybdenum-containing precursor is molybdenum dioxide dichloride (MoO 2 Cl 2 ) a method.

18. 16. The method of claim 15, The method wherein the nucleation layer is formed using atomic layer deposition (ALD).

19. 16. The method of claim 15, The method wherein the bulk layer is formed by chemical vapor deposition (CVD).

20. 16. The method of claim 15, The method wherein the bulk layer is formed by ALD.

21. 16. The method of claim 15, The molybdenum oxychloride used in forming the bulk layer is molybdenum dioxide dichloride (MoO 2 Cl 2 ) a method.

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