Atomic layer deposition of carbon films

Abstract

A carbon film is deposited on a semiconductor substrate by atomic layer deposition using a reaction between an aluminum-containing reactant having an aluminum-carbon bond (e.g., a trialkylaluminum) and a carbon-containing reactant having a carbon-halogen bond (e.g., a fluorocarbon, e.g., CF4 or CH2F2). The method includes sequentially introducing reactants into a processing chamber, forming an adsorption-limited layer of one or both reactants on the surface of the semiconductor substrate, and reacting the aluminum-containing reactant with the carbon-containing reactant to form a carbon layer whose amount is limited by the adsorption-limited reactant layer. Aluminum-containing byproducts are removed from the processing chamber. Such a carbon layer can be used in gap filling applications, such as in 3D NAND manufacturing, and as an insulator in a self-aligned double patterning process.

Description

[0001] Incorporated by Reference

[0002] The PCT application form is filed concurrently with this specification as a part of this application. Each application to which this application claims the benefit or priority as identified in the concurrently filed PCT application form is incorporated herein by reference in its entirety and for all purposes. Technical Field

[0003] The present invention relates to methods of fabricating semiconductor devices. In particular, embodiments of the present invention relate to methods of depositing carbon films in semiconductor processing. Background Art

[0004] In integrated circuit (IC) manufacturing, deposition and etching techniques are used to form patterns of materials, such as for forming metal lines embedded in dielectric layers. Some patterning schemes require conformal deposition of materials, where the deposited layer should follow the contours of raised and / or recessed features on the substrate surface. Atomic layer deposition (ALD) is generally the preferred method for forming conformal films on substrates because ALD relies on the adsorption of one or more reactants to the substrate surface, and the subsequent chemical conversion of the adsorbed layer to the desired material. Because ALD uses reactions that occur at the substrate surface and are generally limited by the amount of adsorbed reactants, the method can provide thin conformal layers with excellent step coverage.

[0005] The background description provided here is for the purpose of generally presenting the context of the present disclosure. The work of the presently designated inventors is neither explicitly nor implicitly admitted to be prior art against the present disclosure to the extent that it is described in this background section and in aspects of the description that could not be determined as prior art at the time the application was filed. Summary of the invention

[0006] Methods for depositing carbon layers by ALD have not been previously developed. Therefore, deposition of carbon layers with a high degree of control over the deposition thickness and good step coverage presents a challenging problem. Provided herein are methods and apparatus for depositing carbon layers in a surface-controlled manner. Conformal carbon films with excellent step coverage can be deposited by the provided methods and can be used in a variety of applications, including gap filling (e.g., gap filling in 3D NAND structures) and during spacer formation in self-aligned double patterning (SADP).

[0007] In one aspect, a method for forming a carbon layer on a surface of a semiconductor substrate in a processing chamber is provided, wherein the method comprises: (a) introducing an aluminum-containing reactant into the processing chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond (e.g., wherein the reactant is an alkyl-substituted aluminum, such as a trialkylaluminum); (b) introducing a carbon-containing reactant into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and wherein the carbon-containing reactant is different from the aluminum-containing reactant (e.g., wherein the carbon-containing reactant is a carbon tetrahalide); (c) causing at least one of the aluminum-containing reactant and the carbon-containing reactant to adsorb onto the surface of the semiconductor substrate under conditions such that one or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limited layer on the surface of the semiconductor substrate; and (d) after at least one of the aluminum-containing reactant and the carbon-containing reactant has formed an adsorption-limited layer on the surface of the semiconductor substrate, causing the aluminum-containing reactant to react with the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate. Operations (a) to (d) may be repeated as many times as necessary to deposit a carbon layer having a predetermined thickness.

[0008] Suitable aluminum-containing reactants include trialkylaluminum. In one example, the aluminum-containing reactant is trimethylaluminum. Examples of suitable carbon-containing reactants having a carbon-halogen bond include CX 4 , CHX 3 , CH 2 X 2 and CH 3 X, wherein X is a halogen. In some embodiments, the carbon-containing reactant is a carbon tetrahalide. In some embodiments, the carbon-containing reactant comprises a carbon-fluorine bond.

[0009] In one embodiment, the aluminum-containing reactant is a trialkylaluminum and the carbon-containing reactant is CX 4 , CHX 3 , CH 2 X 2 and CH 3 One or more of X, wherein X is a halogen. In some embodiments, the halogen is fluorine. In other embodiments, the halogen is chlorine and / or bromine. In a specific example, the aluminum-containing reactant is a trialkylaluminum (e.g., trimethylaluminum or triethylaluminum), and the carbon-containing reactant is CF 4 , CCl 4 or CBr 4 .

[0010] The reaction between the aluminum-containing reactant and the carbon-containing reactant results in the formation of an aluminum-containing byproduct, which can be removed after the reaction is completed. The byproduct typically contains an aluminum-halogen bond. For example, if the carbon-containing reactant contains a carbon-fluorine bond, the byproduct will contain aluminum fluoride.

[0011] The introduction of the reactants into the processing chamber is performed sequentially, and the processing chamber is purged and / or evacuated after the introduction of the first reactant and before the introduction of the second reactant. The reactants can be introduced in any order. In one embodiment, an aluminum-containing reactant having an aluminum-carbon bond is first introduced into the processing chamber and allowed to form an adsorption-restricted layer on the surface of the substrate. Next, the unadsorbed aluminum-containing reactant is removed from the processing chamber (e.g., by purging and / or pumping), and then a carbon-containing reactant is introduced into the processing chamber and allowed to react with the adsorbed aluminum-containing reactant layer to form a carbon layer. Next, the aluminum-containing byproducts can be removed, and the process can be repeated as many times as desired to deposit a carbon layer of a predetermined thickness.

[0012] In another embodiment, the process begins by first introducing a carbon-containing reactant into a process chamber and forming an adsorption-limited carbon-containing reactant layer on a substrate. Unadsorbed carbon-containing reactants are removed from the process chamber by sweeping and / or pumping. Next, an aluminum-containing reactant is introduced into the process chamber and reacts with the adsorbed carbon-containing reactant layer to form a carbon layer on the surface of the substrate.

[0013] In some embodiments, the reaction between the aluminum-containing reactant and the carbon-containing reactant occurs thermally without activation. In other embodiments, the reaction is activated, for example, by plasma treatment of a substrate having an aluminum-containing reactant layer and a carbon-containing reactant layer formed thereon. In one implementation, the carbon deposition method of the method includes adsorbing both the aluminum-containing reactant and the carbon-containing reactant onto a surface of the substrate, and activating the reaction between the adsorbed reactants on the substrate by exposing the substrate to a plasma formed in a process gas, the process gas comprising a gas selected from the group consisting of helium (He), argon (Ar), hydrogen (H 2 ), and nitrogen (N 2 ) group of gases.

[0014] In an exemplary implementation, a plasma activation method for forming a carbon layer on a surface of a semiconductor substrate in a process chamber includes: (a) introducing an aluminum-containing reactant into the process chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond and forms a layer of the aluminum-containing reactant on the surface of the semiconductor substrate; (b) removing the aluminum-containing reactant from the process chamber after (a); (c) introducing a carbon-containing reactant into the process chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond and wherein the carbon-containing reactant is different from the aluminum-containing reactant and forms a layer of the carbon-containing reactant on the surface of the semiconductor substrate; (d) removing the carbon-containing reactant from the process chamber after (c); and (d) contacting the semiconductor substrate having the layer of the carbon-containing reactant and the layer of the aluminum-containing reactant with plasma to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant, thereby forming a carbon layer on the surface of the semiconductor substrate. Operations (a)-(d) may be repeated as many times as needed to deposit a carbon layer of a desired thickness. In one example, the aluminum-containing reactant is trialkylaluminum, and the carbon-containing reactant is CF 4 and by mixing the semiconductor substrate with a gas selected from the group consisting of helium (He), argon (Ar), hydrogen (H 2 ) and nitrogen (N 2 ) is contacted with a process gas to form a plasma to activate the trialkylaluminum and CF 4 The reaction between.

[0015] In some embodiments, the surface of the semiconductor substrate on which the carbon layer is formed has patterned three-dimensional features. In some implementations, the carbon layer is deposited during a gap-fill operation. For example, the carbon layer can be deposited in a partially fabricated 3D NAND structure during a gap-fill operation.

[0016] In some implementations, the carbon layer is conformally deposited on a semiconductor substrate having a plurality of protruding features. In one embodiment, the method further comprises: completely removing the carbon layer from horizontal surfaces of the protruding features without completely removing the carbon layer on sidewalls of the protruding features; and then removing the protruding features without completely removing the carbon layer residing on the sidewalls of the protruding features, thereby forming carbon spacers on the semiconductor substrate.

[0017] In some embodiments, provided methods further include: applying a photoresist to the substrate; exposing the photoresist to light; patterning the photoresist and transferring the pattern to the substrate; and selectively removing the photoresist from the substrate.

[0018] In another aspect, a partially fabricated semiconductor substrate is provided, wherein the semiconductor substrate includes a plurality of carbon spacers.

[0019] In another aspect, a system for processing a semiconductor substrate is provided. The system includes: a processing chamber having a substrate holder and one or more inlets for introducing reactants into the processing chamber; and a system controller including program instructions for performing any of the methods described herein. In one implementation, the program instructions include program instructions for: (i) causing an aluminum-containing reactant to be introduced into the process chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond; (ii) causing a carbon-containing reactant to be introduced into the process chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond and wherein the carbon-containing reactant is different from the aluminum-containing reactant; (iii) causing at least one of the aluminum-containing reactant and the carbon-containing reactant to be adsorbed onto the surface of the semiconductor substrate under conditions such that one or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-restricted layer on the surface of the semiconductor substrate; and (iv) causing the aluminum-containing reactant to react with the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate after at least one of the aluminum-containing reactant and the carbon-containing reactant has formed an adsorption-restricted layer on the surface of the semiconductor substrate.

[0020] These and other aspects of implementations of the subject matter described in this specification are set forth in the drawings and the description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a process flow diagram of a carbon deposition method according to embodiments provided herein.

[0022] Figure 2A is a process flow diagram of a carbon deposition method according to embodiments provided herein.

[0023] Figure 2B is a process flow diagram of a carbon deposition method according to another embodiment provided herein.

[0024] Figures 3A-3F Shown is a schematic cross-sectional view of a semiconductor substrate undergoing processing according to embodiments provided herein.

[0025] Figure 4 is a process flow diagram of a method of forming a carbon spacer according to an embodiment provided herein.

[0026] Figure 5-6 Shown is a schematic cross-sectional view of a semiconductor substrate undergoing processing according to embodiments provided herein.

[0027] Figure 7 is a schematic diagram of an apparatus suitable for depositing carbon films according to embodiments provided herein.

[0028] Figure 8 A schematic diagram of a multi-station processing system according to embodiments provided herein is shown.

[0029] Fig. 9 A schematic diagram of a multi-station processing system according to embodiments provided herein is shown. DETAILED DESCRIPTION

[0030] Methods for depositing carbon films using ALD are provided. These methods can be used, for example, to deposit conformal carbon films on semiconductor substrates having three-dimensional structures on their surfaces (e.g., on substrates having one or more recessed features or one or more protrusions). In some embodiments, the method comprises reacting an aluminum-containing reactant having an Al-C bond (e.g., a trialkylaluminum) with a carbon-containing reactant having a carbon-halogen bond (e.g., CF 4 ) between them.

[0031] As used herein, the term "ALD" generally refers to a deposition method that relies on a reaction limited by the amount of reactant adsorbed on the substrate surface (adsorption-limited reactant layer). The adsorption-limited reactant layer can include an adsorption-limited aluminum-containing reactant layer, an adsorption-limited carbon-containing reactant layer, or an adsorption-limited two-reactant layer. In some embodiments, the ALD method includes sequentially introducing the reactants into the processing chamber so that the reactants are not allowed to mix in the body of the processing chamber.

[0032] In some embodiments, the carbon film is deposited in gap filling applications. For example, in one implementation, the carbon film can be deposited in gap filling during 3D NAND manufacturing. In some implementations, the carbon film is used as a spacer in self-aligned double patterning (SADP). However, the method provided is not limited to depositing carbon films on surfaces with recessed features, and can also be used to deposit blanket carbon films on flat surfaces. The method relies on surface controlled reactions and can be used to deposit films with a high degree of control over film thickness. The film can be deposited in a variety of devices that allow reactants to be introduced sequentially into the processing chamber. For example, the carbon film can be deposited in a variety of devices that can be obtained from Lam Research Corporation. A carbon film is deposited in a deposition system.

[0033] As used herein, carbon refers to a material consisting essentially of carbon (C) and optionally hydrogen (H). In some embodiments, as used herein, a carbon film may contain C-H bonds. Materials containing hydrocarbons are within the scope of carbon films. Other elements may also be present in the carbon film as dopants in small amounts, less than about 10% (atomic) of the total amount of dopant, wherein hydrogen is not included in the calculation.

[0034] As used herein, the term "semiconductor substrate" refers to a substrate at any stage of semiconductor device manufacturing, which substrate contains semiconductor material anywhere within its structure. It should be understood that the semiconductor material in the semiconductor substrate does not need to be exposed. A semiconductor wafer with multiple layers of other materials (e.g., dielectrics) covering the semiconductor material is an example of a semiconductor substrate. The following detailed description assumes that the disclosed implementation is implemented on a wafer. However, the disclosed implementation is not limited to this. The workpiece can have various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that can utilize the disclosed implementation include various products, such as printed circuit boards, etc.

[0035] The process of depositing carbon film is Figure 1 The process flow diagram shown is illustrated. In operation 101, an aluminum-containing reactant is introduced into a processing chamber containing a semiconductor substrate. The aluminum-containing reactant contains at least one aluminum-carbon bond. In some embodiments, the carbon of the aluminum-carbon bond is part of an alkyl substituent, such as methyl, ethyl, propyl (e.g., n-propyl or isopropyl), butyl, pentyl, etc. In some embodiments, the aluminum-containing reactant is a trialkylaluminum. Examples of suitable reactants include trimethylaluminum, triethylaluminum, etc. In some embodiments, the aluminum-containing reactant is volatile and is introduced into the processing chamber in a gas phase. The reactant can be introduced mixed with a carrier gas, wherein the carrier gas is typically an inert gas, such as N 2 , He, Ar, Ne or Kr. When the aluminum-containing reactant is non-volatile, it can be evaporated using a direct liquid injection (DLI) evaporator, such as the Vapbox DLI evaporator available from Kemstream.

[0036] In operation 103, a carbon-containing reactant is introduced into a processing chamber containing a substrate. The carbon-containing reactant has a carbon-halogen bond, such as at least one of a carbon-fluorine, carbon-chlorine, and carbon-bromine bond. Examples of suitable reactants include CX 4 , CHX 3 , CH 2 X 2 and CH 3 X, wherein X is a halogen. For example, in some embodiments, a halogen such as CF 4 , CHF 3 , CH 2 F 2 or CH 3 In other embodiments, chlorine-containing reactants such as CCl 4 , CHCl 3 , CH 2 Cl 2 or CH 3 Cl.

[0037] The aluminum-containing reactant and the carbon-containing reactant are typically introduced sequentially into the processing chamber without mixing in the main body of the processing chamber. The order of introduction may vary depending on the embodiment. In some embodiments, the aluminum-containing reactant is introduced first, and then the carbon-containing reactant is introduced. In other embodiments, the carbon-containing reactant is introduced first, and then the aluminum-containing reactant is introduced. At least one of the reactants (e.g., the aluminum-containing reactant, the carbon-containing reactant, or both) forms an adsorption-restricted layer on the substrate. In some embodiments, the first reactant introduced forms an adsorption-restricted layer on the substrate, and the second reactant introduced reacts with the adsorption-restricted layer after the second introduced reactant contacts the adsorption-restricted layer of the first reactant. In other embodiments, the first reactant introduced forms an adsorption-restricted layer, the second reactant introduced also forms an adsorption-restricted layer, and the two reactants then react on the surface of the substrate, for example after thermal activation or plasma activation. In some embodiments, the substrate is exposed to a gas such as helium (He), argon (Ar), hydrogen (H 2 ) and nitrogen (N 2 ) or any mixture thereof to activate the reaction. In order to allow carbon to be formed at a relatively low temperature, a plasma-activated reaction can be used. In some embodiments, a carbon film is formed using a plasma-activated reaction at a temperature of less than 300° C., for example, less than 200° C.

[0038] Regardless of the order of introduction, in some embodiments, the process chamber is purged and / or pumped down after the introduction of the first reactant and before the introduction of the second reactant in order to remove unadsorbed introduced first reactant from the process chamber.

[0039] In operation 105, the aluminum-containing reactant is reacted with the carbon-containing reactant to form a carbon layer on the surface of the substrate, wherein the amount of carbon formed is limited by the adsorption-limited reactant (e.g., aluminum-containing reactant and / or carbon-containing reactant) layer. In this reaction, the aluminum-carbon bond of the aluminum-containing reactant and the carbon-halogen bond of the carbon-containing reactant are broken to form carbon (which may include a C-H bond), and the by-product contains an aluminum-halogen bond. For example, when the halogen in the carbon-containing reactant is fluorine, a by-product containing an aluminum-fluorine bond will be formed. In some embodiments, the reaction occurs spontaneously after the reactants are contacted. In other embodiments, the reaction is activated (e.g., by thermal means) after the reactants have been contacted.

[0040] In some embodiments, aluminum halide byproducts are removed from the substrate surface while the carbon is being formed. In other embodiments, aluminum-containing byproducts are removed from the substrate in a separate step, as shown in operation 107. For example, the substrate can be heated to remove volatile aluminum halide (e.g., aluminum fluoride) byproducts.

[0041] In some embodiments, including a deposition cycle of operations 101-105, the average thickness of the deposition is between 0.5 angstroms. to The cycle can be repeated as many times as needed to deposit a carbon film of a desired thickness. For example, in some embodiments, the deposition thickness is between to The carbon film between them.

[0042] One embodiment of the carbon deposition method comprises Figure 2A The process flow diagram shown is illustrated. The process begins at 201 by adsorbing an aluminum-containing reactant on a semiconductor substrate. An aluminum-containing precursor, such as a trialkylaluminum, can be flowed into a process chamber along with a carrier gas and can be allowed to adsorb onto the surface of the substrate. The process conditions of this step are selected so that an adsorption-limited aluminum-containing reactant layer is formed. Next, in operation 203, the unadsorbed aluminum-containing reactant is removed from the process chamber by purging and / or pumping the process chamber. For example, an inert gas (e.g., N) can be used to remove the unadsorbed aluminum-containing reactant from the process chamber. 2 , He, Ar, Ne, etc.) to purge the processing chamber. After this step, there is no aluminum-containing precursor in the main body of the processing chamber, and all subsequent reactions are limited by the amount of aluminum-containing reactants adsorbed on the substrate. Next, in operation 205, a carbon-containing reactant is introduced into the processing chamber and reacted with the adsorbed aluminum-containing reactant to form a carbon layer on the surface of the semiconductor substrate. In some embodiments, the reaction occurs spontaneously after the introduction of the carbon-containing reactant.

[0043] Next, in operation 207, the aluminum-containing byproducts are removed from the process chamber. This step is optional, as in some embodiments, the byproducts are removed while the carbon is formed. When the byproduct is not removed while the carbon forming reaction is taking place, it can be removed in a separate step, such as by heating.

[0044] Next, in operation 209, the carbon deposition (steps 201-207) is repeated as many times as needed to form a carbon layer of predetermined thickness. For example, in some embodiments, at least 5 or at least 10 cycles are performed, each of which includes operations 201-205. The temperature and pressure during the treatment are controlled so that an adsorption-limited layer of one or both reactants can be formed on the substrate. In some embodiments, the temperature during the entire deposition sequence is maintained at less than about 400°C and the pressure is maintained at a level below atmospheric pressure. The use of the reactants to deposit a carbon film can be carried out in the absence of plasma. In some embodiments, plasma treatment can be used, for example, to improve the quality of the deposited carbon layer after deposition and / or to activate one or more reactants on the substrate surface.

[0045] Figure 2B A process flow chart of a method for forming a carbon layer using a plasma activated reaction is provided. Figure 2B , the process begins in 211 by forming an aluminum-containing reactant layer on a substrate. For example, an adsorption-limited aluminum-containing reactant layer may be formed on the substrate. Next, in operation 213, the process chamber is purged and / or evacuated to remove the aluminum-containing reactant from the process chamber. For example, an inert gas may be used as a purge gas to remove unadsorbed aluminum-containing reactants. Next, in operation 215, a carbon-containing material layer is formed on the substrate. For example, a carbon-containing material may be introduced into the process chamber, and the carbon-containing material may be caused to form an adsorption-limited layer on the substrate. In operation 217, the process chamber is purged and / or evacuated to remove the carbon-containing material from the process chamber. After this operation, there is an aluminum-containing material layer and a carbon-containing material layer on the surface of the substrate. Next, in operation 219, the substrate is treated with plasma to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant on the substrate and form a carbon layer. In some embodiments, the plasma is in the presence of helium (He), argon (Ar), hydrogen (H2), or the like. 2 ), nitrogen (N 2 ) or any mixture of these gases. The reaction byproducts can be removed simultaneously with the plasma treatment or in a subsequent step. After the plasma treatment, the processing chamber can be purged and / or evacuated, and the processing sequence of steps 211-219 can be repeated multiple times in operation 221 until a carbon layer having a predetermined thickness is deposited. In an exemplary embodiment, the aluminum-containing reactant is a trialkylaluminum (e.g., trimethylaluminum or triethylaluminum), and the carbon-containing reactant is CF 4 .

[0046] The carbon films deposited by the methods provided herein can be used for a variety of applications in semiconductor device manufacturing. They are particularly useful when conformal deposition of films is required on substrates with three-dimensional features (e.g., protruding features or recessed features). In some embodiments, the carbon films are used as spacers in patterning applications. Figures 3A-3F An example of forming carbon spacers is provided in , which shows schematic cross-sectional views of a semiconductor substrate at different processing stages. Figure 4 An exemplary process flow diagram of a method of semiconductor processing involving carbon mandrel formation is provided.

[0047] Reference Figure 4 The depicted process begins in 401 by providing a substrate having a plurality of protruding features (also referred to as mandrels). Figure 3A, an exemplary substrate is shown, which shows two mandrels 301 located on an etch stop layer (ESL) 303. In some embodiments, the distance d1 between adjacent mandrels is between about 10-100nm. In some embodiments, a relatively large distance of about 40-100nm is used. In other applications, the distance between the closest mandrels is between about 10-30nm. In certain embodiments, the distance d2 (also referred to as the pitch) between the centers closest to the mandrels is between about 30-130nm. In some embodiments, the pitch is between about 80-130nm. In other embodiments, the pitch is between about 30-40nm. The height of the mandrel d3 is typically between about 20-200nm, for example, between about 50-100nm.

[0048] The materials of the mandrel and the ESL are selected so that the mandrel material can be selectively etched in the presence of exposed carbon, and the ESL material can be selectively etched in the presence of exposed carbon. Thus, for the first etching chemistry, the ratio of the etching rate of the ESL material to the etching rate of the carbon is greater than 1, more preferably greater than about 1.5, for example, greater than about 2. In some embodiments, the ESL material is a silicon-containing material (e.g., a silicon-containing compound such as silicon nitride), and the first etching chemistry is a fluorine-based plasma etch (e.g., a plasma formed in a gas containing a fluorocarbon). In some embodiments, the ESL material is a metal oxide or a metal nitride, and the first etching chemistry is a halogen-based plasma etch (e.g., a plasma formed in a process gas containing a halogen). Similarly, for the second etching chemistry, the ratio of the etching rate of the mandrel material to the etching rate of the carbon is greater than 1, more preferably greater than about 1.5, for example, greater than about 2. In some embodiments, the mandrel material is a silicon-containing material (e.g., a silicon-containing compound), and the first etching chemistry is a fluorine-based plasma etch (e.g., a plasma formed in a gas containing a fluorocarbon). In some embodiments, the mandrel material is a metal oxide or a metal nitride, and the first etch chemistry is a halogen-based plasma etch (eg, a plasma formed in a process gas containing a halogen).

[0049] In some embodiments, the ESL material is a silicon-containing compound (e.g., SiO 2 ) or metal oxides (e.g., titanium oxide, zirconium oxide, tungsten oxide). The mandrel material may include a silicon-containing compound (e.g., SiO 2, SiN or SiC), amorphous silicon (doped or undoped) or metal oxides (TaO, TiO, WO, ZrO, HfO). In some embodiments, the outer material of the mandrel can be different from the mandrel core. For example, in some embodiments, the mandrel is made of amorphous silicon covered with silicon oxide (e.g., with a spontaneously formed thermal oxide layer). The ESL layer and the mandrel can be formed by one or more of physical vapor deposition (PVD), chemical vapor deposition (CVD), ALD (plasma-free or by PEALD), or plasma enhanced chemical vapor deposition (PECVD), and the pattern of the mandrel can be defined using photolithography. Examples of suitable ESL / mandrel combinations include: (i) silicon oxide ESL and silicon oxide-covered silicon mandrel; (ii) silicon oxide ESL and metal oxide mandrel; (iii) metal oxide ESL and silicon oxide-covered silicon mandrel.

[0050] Reference again Figure 3A The substrate shown in FIG. 1 is a substrate with an ESL layer 303 located above and in contact with a target layer 305. The target layer 305 is a layer to be patterned. The target layer 305 may be a semiconductor layer, a dielectric layer, or other layer, and may be made of, for example, silicon (Si), silicon oxide (SiO 2 ), silicon nitride (SiN) or titanium nitride (TiN). In some embodiments, the target layer is referred to as a hard mask layer and comprises a metal nitride, such as titanium nitride. The target layer 305 can be deposited by ALD (without plasma or by PEALD), CVD or other suitable deposition techniques.

[0051] Target layer 305 is located above and in contact with layer 307 , which in some embodiments is a BEOL layer that includes a plurality of metal lines embedded in a layer of dielectric material.

[0052] Reference Figure 4 , processing of the substrate continues in 403 by depositing a carbon layer on both horizontal surfaces and sidewalls of protruding features. The carbon layer is preferably conformally deposited using the ALD method provided herein. Figure 3B In the structure shown, a carbon layer 309 is deposited over the ESL 303 and over the mandrel 301, including over the sidewalls of the mandrel. In the embodiment shown, the carbon layer is deposited by the ALD method developed herein. In some embodiments, the carbon layer is conformally deposited to a thickness between about 5-30 nm, such as between about 10-20 nm.

[0053] After the carbon layer is conformally deposited, in 405, the process continues by completely removing the carbon layer from horizontal surfaces without completely removing the carbon layer from the sidewalls of the protruding features. The etch can be performed using an oxygen-based plasma etch (e.g., using a plasma formed in a gas containing oxygen). In other embodiments, a hydrogen-based etch can be used (e.g., using a plasma formed in a process gas containing hydrogen). If the mandrel has a silicon-containing compound or a metal oxide as an outer layer, a hydrogen-based or oxygen-based etch can be used. The etching chemistry used in this step should preferably be selective to both the ESL material and the material of the outer layer of the mandrel, that is, for the etching chemistry, the etch rate of carbon should be greater than the etch rate of the outer mandrel material and greater than the etch rate of the ESL material. Figure 3C The removal of the carbon layer from the horizontal surface is shown. The carbon layer 309 is etched away from the horizontal surface above the ESL 303 and above the mandrel 301, but is not completely etched from the location attached to the side wall of the mandrel 301. This etching layer exposes the carbon layer 303 everywhere except near the side wall of the mandrel 301. In addition, this etching exposes the top of the mandrel. The resulting structure is shown in FIG. Figure 3C Preferably, after the etching, at least 50%, such as at least 80% or at least 90%, of the initial height of the carbon layer at the sidewalls is retained. In one example, by a hydrogen-based etch (e.g., H 2 Plasma etching) selectively etches carbon from the silicon oxide covered mandrel, leaving the outer material of the mandrel (SiO 2 ) is exposed. Hydrogen-based etching of SiO 2 In another example, by a hydrogen-based etch (e.g., H 2 plasma etching) or oxygen-based etching (e.g., O 2 Plasma etching) selectively etches carbon from metal oxide (e.g., titanium oxide) mandrels, exposing the mandrel material (metal oxide). These etching chemistries are selective to metal oxides (e.g., titanium oxide) that do not form volatile hydrides.

[0054] The next step 407 involves completely removing the protruding features without completely removing the carbon layer at the sidewalls of the protruding features, thereby forming carbon spacers. Figure 3DAs shown, the mandrel 301 is removed from the substrate, leaving exposed carbon spacers 301 and exposed layer ESL 303. Removal of the mandrel is performed by exposing the substrate to an etching chemistry that selectively etches the mandrel material. Therefore, in this step, the ratio of the etching rate of the mandrel material to the etching rate of carbon is greater than 1, and more preferably greater than 1.5. In addition, in some embodiments, the etching chemistry used in this step should selectively etch the mandrel material relative to the ESL material. A variety of etching methods can be used, and the specific choice of chemistry depends on the material of the mandrel and the material of the ESL layer. When the mandrel is made of amorphous silicon covered with silicon oxide, a fluorine-based chemistry (e.g., NF 3 ) Silicon mandrels 301 are connected to the SiO 2 The chemical is selective for carbon.

[0055] When the mandrel is a metal oxide (e.g., titanium oxide, tungsten oxide, zirconium oxide, hafnium oxide, tantalum oxide), a chlorine-based etch chemistry (e.g., BCl in a plasma) can be used. 3 / Cl 2 ) to selectively remove the mandrel relative to carbon. 2 This chemical substance is used in the presence of ESL of SiN, SiC).

[0056] Next, the exposed ESL film 303 is etched to expose the underlying target layer 305 at all locations not protected by the carbon spacers 309. Figure 3E The resulting structure is shown in FIG. 1 . The etching chemistry used in this step selectively etches the ESL material in the presence of carbon. In other words, the ratio of the etch rate of the ESL material to the etch rate of the carbon is greater than 1, and more preferably greater than 1.5. The specific type of chemistry used in this step will depend on the type of ESL material. When using silicon-containing compounds (e.g., silicon oxide and silicon oxide-based materials), selective etching can be accomplished by exposing the substrate to a plasma formed in a process gas containing a fluorocarbon. For example, the selective etching can be accomplished by exposing the substrate to a plasma formed in a process gas containing a fluorocarbon. 4 , C 2 F 6 and C 3 F 8 The ESL film is etched by a plasma formed in one or more process gases. When the ESL is a metal oxide layer (e.g., titanium oxide, tungsten oxide, or zirconium oxide), a chlorine-based etching chemistry (e.g., BCl in the plasma) can be used. 3 / Cl 2 ) is selectively etched in the presence of carbon.

[0057] In the next step, the target layer 305 is etched at all locations not protected by the ESL film 303 to expose the underlying layer 307. The carbon spacer layer 309 is also removed in this etching step, thereby providing Figure 3F 305 and the carbon spacer 309. In some embodiments, the etching chemistry used in this step is selected to remove both the target material and the carbon spacer material. In other embodiments, two different etching steps using different chemistries can be used to pattern the target layer 305 and remove the carbon spacer 309, respectively. Depending on the chemical nature of the target layer, a variety of etching chemistries can be used. In one embodiment, the target layer 305 is a metal nitride layer (e.g., TiN). In this embodiment, the substrate can be exposed to a Cl 2 and hydrocarbons (e.g., CH 4 ) to etch the metal nitride layer, and then remove the carbon spacers using an oxygen-based plasma etch chemistry or a hydrogen-based plasma etch chemistry.

[0058] In some embodiments, the provided carbon deposition method is used in gap filling applications. In gap filling, a substrate comprising one or more recessed features is provided to a processing chamber, and carbon is deposited using the provided method to cover the bottom and sidewalls of the recessed features. Deposition cycles are performed multiple times as needed to fill the recessed features with carbon. Due to the highly conformal nature of the deposition, seamless gap filling can be achieved in some embodiments. The provided method is particularly effective for depositing carbon in high aspect ratio features. In some embodiments, the aspect ratio of the recessed features is at least 5:1, for example at least 10:1.

[0059] In one example, carbon is used for gap filling in a 3D NAND manufacturing process. In one implementation, a partially fabricated 3D NAND structure having at least one recessed feature is provided to a processing chamber, and carbon is deposited into the at least one recessed feature to fill the recessed feature using the methods provided herein. Figure 5 and Figure 6 Provides a graphic representation of the application. Figure 5 and Figure 6 A schematic cross-sectional view of a partially fabricated 3D NAND structure is illustrated.

[0060] Figure 5An exemplary substrate 1100 is shown having a plurality of alternating layers 1111 and 1140 deposited in a staircase pattern on substrate 1100. In some embodiments, layer 1111 is a dielectric layer (e.g., silicon oxide) and layer 1140 is a conductive layer (e.g., tungsten layer). Alternatively, layers 1111 and 1140 can be different types of dielectrics, such as silicon oxide layer 1111 and silicon nitride layer 1140. A hard mask layer 1110 resides on top layer 1140, and encapsulation layer 1139 laterally encapsulates the staircase pattern of alternating layers 1111. A plurality of vias 1137 are etched in dielectric 1122 (e.g., in silicon oxide), such that material of layer 1140 is exposed at bottom 1139 of vias 1137. Vias 1137 have different depths because material 1140, such as Figure 5 In the next step, carbon is deposited into the via 1137 in a gap filling operation using the deposition method provided herein. The resulting structure is Figure 6 1 is shown in which a carbon layer 1173 fills all vias (trenches) and where the carbon is in contact with material 1140 at the bottom of the filled vias. The carbon can be used as a sacrificial material in the trenches, and during subsequent manufacturing, the carbon can be removed from the trenches, for example using an oxygen-based plasma etch or a hydrogen-based plasma etch, and the vias can be filled with a conductive material.

[0061] Device

[0062] The carbon deposition methods described herein can be performed in a variety of apparatuses. One suitable apparatus includes: a process chamber having one or more inlets for introducing reactants; a substrate holder in the process chamber configured to hold the substrate in place during deposition; and optionally, a plasma generating mechanism configured to generate plasma in the process gas. The apparatus may include a controller having program instructions for causing any of the method steps described herein to be performed. An example of a suitable apparatus is the LAMBDA®, available from Lam Research Corporation. Deposition device.

[0063] For example, in some embodiments, the apparatus includes a controller having program instructions, the program instructions including instructions for: (i) causing an aluminum-containing reactant to be introduced into the processing chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond; (ii) causing a carbon-containing reactant to be introduced into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and wherein the carbon-containing reactant is different from the aluminum-containing reactant; (iii) causing at least one of the aluminum-containing reactant and the carbon-containing reactant to be adsorbed onto the surface of the semiconductor substrate under conditions such that one or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limited layer on the surface of the semiconductor substrate; and (iv) causing the aluminum-containing reactant to react with the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate after at least one of the aluminum-containing reactant and the carbon-containing reactant has formed an adsorption-limited layer on the surface of the semiconductor substrate.

[0064] Figure 7 An example of a deposition apparatus suitable for depositing carbon using the provided methods is shown. Figure 7 Schematically illustrates an embodiment of a process station 700 that can be used to deposit materials using atomic layer deposition (ALD) and / or chemical vapor deposition (CVD), either of which can be plasma enhanced. For simplicity, the process station 700 is depicted as a stand-alone process station having a process chamber body 702 for maintaining a low pressure environment. However, it should be understood that multiple process stations 700 can be included in a common process tool environment. In addition, it should be understood that in some embodiments, one or more hardware parameters of the process station 700, including those discussed in detail below, can be programmatically adjusted by one or more computer controllers.

[0065] The processing station 700 is in fluid communication with a reactant delivery system 701 to deliver process gases to a distribution showerhead 706. The reactant delivery system 701 includes a mixing vessel 704 for blending and / or conditioning process gases for delivery to the showerhead 706. One or more mixing vessel inlet valves 720 can control the introduction of process gases into the mixing vessel 704. Similarly, a showerhead inlet valve 705 can control the introduction of process gases into the showerhead 706.

[0066] Some reactants (e.g., trimethylaluminum) may be stored in liquid form prior to vaporization at a processing station and subsequent transport to a processing station. Figure 7Embodiments include vaporization point 703, which is used to vaporize liquid reactants to be supplied to mixing container 704. In some embodiments, vaporization point 703 can be a heated evaporator. Reactant vapors produced from such evaporators will condense in downstream delivery pipelines. Incompatible gases exposed to condensed reactants will produce small particles. These small particles may block pipelines, hinder valve operation, contaminate substrates, etc. Some methods for dealing with these problems involve cleaning and / or evacuating delivery pipelines to remove residual reactants. However, cleaning delivery pipelines will increase the processing station cycle time and reduce the processing station throughput. Therefore, in some embodiments, the delivery pipeline downstream of vaporization point 703 can be heat traced. In some examples, mixing container 704 can also be heat traced. In a non-limiting example, the pipeline downstream of vaporization point 703 has a temperature distribution of an increase from about 100°C to about 150°C at mixing container 704.

[0067] In some embodiments, the reactant liquid can be vaporized at the liquid injector. For example, the liquid injector can inject a pulse of the liquid reactant into the carrier gas flow upstream of the mixing vessel. In one case, the liquid injector can vaporize the reactant by flashing the liquid from a higher pressure to a lower pressure. In another case, the liquid injector can atomize the liquid into dispersed droplets that are then vaporized in a heated delivery pipe. It should be understood that smaller droplets can vaporize faster than larger droplets, thereby reducing the delay between liquid injection and completion of vaporization. Faster vaporization can reduce the length of the pipeline downstream of the vaporization point 703. In one case, the liquid injector can be directly loaded into the mixing vessel 704. In another case, the liquid injector can be directly loaded into the spray head 706.

[0068] In some embodiments, a liquid flow controller can be set upstream of the vaporization point 703 to control the mass flow of the liquid for vaporization and delivery to the processing station 700. For example, a liquid flow controller (LFC) can include a thermal mass flow meter (MFM) located downstream of the LFC. The plunger valve of the LFC can then be adjusted in response to a feedback control signal provided by a proportional integral differential (PID) controller that is electrically communicated with the MFM. However, it can take one second or longer to use feedback control to stabilize the liquid flow. This can extend the time of dosing liquid reactants. Therefore, in some embodiments, the LFC can be dynamically switched between a feedback control mode and a direct control mode. In some embodiments, the LFC can be dynamically switched to a direct control mode from a feedback control mode by disabling the sensing pipeline and PID controller of the LFC.

[0069] The showerhead 706 distributes process gases toward the substrate 712. Figure 7In the illustrated embodiment, substrate 712 is positioned below showerhead 706 and is shown resting on pedestal 708. It will be appreciated that showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports to distribute process gases to substrate 712.

[0070] In some embodiments, microvolume 707 is located below showerhead 706. Performing ALD and / or CVD processes in a microvolume rather than in the entire volume of a processing station can reduce reactant exposure and purge time, can reduce the time to change process conditions (e.g., pressure, temperature, etc.), can limit the exposure of the processing station robot to process gases, etc. Exemplary microvolume sizes include, but are not limited to, volumes between 0.1 liters and 2 liters. This microvolume also affects productivity throughput. When the deposition rate per cycle decreases, the cycle time is also reduced. In some cases, for a given target film thickness, the effect of the cycle time reduction is significant enough to increase the overall yield of the module.

[0071] In some embodiments, the pedestal 708 can be raised or lowered to expose the substrate 712 to the microvolume 707 and / or to change the volume of the microvolume 707. For example, during a substrate transfer phase, the pedestal 708 can be lowered so that the substrate 712 can be loaded on the pedestal 708. During a deposition process phase, the pedestal 708 can be raised to position the substrate 712 within the microvolume 707. In some embodiments, the microvolume 707 can completely surround the substrate 712 and a portion of the pedestal 708 to form an area of ​​high flow impedance during the deposition process.

[0072] Optionally, the pedestal 708 can be lowered and / or raised during portions of the deposition process to adjust process pressure, reactant concentrations, etc. within the microvolume 707. In one case where the process chamber body 702 is maintained at a base pressure during the deposition process, lowering the pedestal 708 can allow the microvolume 707 to be evacuated. Exemplary ratios of microvolume to process chamber volume include, but are not limited to, volume ratios between 1:700 and 1:10. It should be understood that in some embodiments, the pedestal height can be programmatically adjusted by a suitable computer controller.

[0073] Although the exemplary microvolume variations described herein relate to a height-adjustable pedestal, it should be understood that in some embodiments, the position of the showerhead 706 can be adjusted relative to the pedestal 708 to change the volume of the microvolume 707. In addition, it should be understood that the vertical position of the pedestal 708 and / or showerhead 706 can be changed by any suitable mechanism within the scope of the present disclosure. In some embodiments, the pedestal 708 may include a rotation axis for rotating the orientation of the substrate 712. It should be understood that in some embodiments, one or more of these exemplary adjustments can be performed programmatically by one or more appropriate computer controllers.

[0074] Back to Figure 7 In the embodiment shown, the showerhead 706 and the base 708 are electrically communicated with the RF power source 714 and the matching network 716 for powering the plasma. In other embodiments, a device without a plasma generator is used to deposit carbon using the provided method. In some embodiments, the energy of the plasma can be controlled by controlling one or more of the pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing of the processing station. For example, the RF power source 714 and the matching network 716 can be operated at any suitable power to form a plasma with a component of a desired free radical substance. The embodiment of suitable power is included above. Similarly, the RF power source 714 can provide RF power of any appropriate frequency. In some embodiments, the RF power source 714 can be configured to control a high-frequency RF power source and a low-frequency RF power source that are independent of each other. Exemplary low-frequency RF frequencies may include, but are not limited to, frequencies between 50kHz and 700kHz. Exemplary high-frequency RF frequencies may include, but are not limited to, frequencies between 1.8MHz and 2.45GHz. It should be understood that any suitable parameters may be discretely or continuously adjusted to provide plasma energy for surface reactions. In one non-limiting example, the plasma power may be intermittently pulsed to reduce ion bombardment of the substrate surface relative to a continuously powered plasma.

[0075] In some embodiments, the plasma can be monitored in situ by one or more plasma monitors. In one case, the plasma power can be monitored by one or more voltage and current sensors (e.g., VI probes). In another case, the plasma density and / or the concentration of the process gas can be measured by one or more optical emission spectrometer sensors (OES). In some embodiments, one or more plasma parameters can be adjusted programmatically based on the measurement results from such an in-situ plasma monitor. For example, an OES sensor can be used in a feedback loop to provide programmatic control of the plasma power. It should be understood that in some embodiments, other monitors can be used to monitor plasma and other process characteristics. Such monitors may include, but are not limited to, infrared (IR) monitors, acoustic monitors, and pressure sensors.

[0076] In some embodiments, plasma can be controlled via input / output control (IOC) sequencing instructions. In one example, instructions for setting plasma conditions for a plasma treatment phase may be included in a corresponding plasma activation recipe phase of a deposition process recipe. In some cases, the process recipe phases may be arranged in sequence so that all instructions for a deposition process phase are executed simultaneously with the process phase. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe phase before the plasma treatment phase. For example, a first recipe phase may include instructions for setting the flow rate of an inert gas and / or a reactant gas, instructions for setting a plasma generator to a power set point, and time delay instructions for a first recipe phase. A second subsequent recipe phase may include instructions for enabling a plasma generator and time delay instructions for a second recipe phase. A third recipe phase may include instructions for disabling a plasma generator and time delay instructions for a third recipe phase. It should be understood that these recipe phases may be further subdivided and / or iterated in any suitable manner within the scope of the present disclosure.

[0077] In some embodiments, the susceptor 708 can be temperature controlled by a heater 710. Additionally, in some embodiments, pressure control of the deposition processing station 700 can be provided by a butterfly valve 718. Figure 7 In the embodiment shown in FIG. 7 , butterfly valve 718 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, the pressure control of the process station 700 can also be adjusted by changing the flow rate of one or more gases introduced into the process station 700.

[0078] Figure 8A schematic diagram of an embodiment of a multi-station processing tool 800 is shown, which has an inbound load lock 802 and an outbound load lock 804, one or both of which may include a remote plasma source. Such a tool can be used to process substrates using the methods provided herein. At atmospheric pressure, a robot 806 is configured to move a wafer from a box loaded by a wafer boat 808 into the inbound load lock 802 via an atmospheric port 810. The wafer is placed on a pedestal 812 in the inbound load lock 802 by the robot 806, the atmospheric port 810 is closed, and the load lock is evacuated. When the inbound load lock 802 includes a remote plasma source, the wafer can be exposed to a remote plasma treatment in the load lock before being introduced into the processing chamber 814. In addition, the wafer can also be heated in the inbound load lock 802, for example to remove moisture and adsorbed gases. Next, a chamber transfer port 816 leading to the processing chamber 814 is opened, and another robot (not shown) places the wafer into the reactor on a pedestal at the first station shown in the reactor for processing. Although Figure 8 The illustrated embodiment includes a load lock, but it will be appreciated that in some embodiments, wafers may be allowed to enter the processing station directly.

[0079] The depicted processing chamber 814 contains four processing stations, Figure 8 In the embodiment shown, the stations are numbered 1 to 4. Each station has a heated susceptor (shown as 818 for station 1) and a gas line inlet. It should be understood that in some embodiments, each processing station can have different or multiple uses. Although the processing chamber 814 depicted includes 4 stations, it should be understood that the processing chamber according to the present disclosure can have any suitable number of stations. For example, in some embodiments, the processing chamber can have 5 or more stations, while in other embodiments, the processing chamber can have 3 or less stations.

[0080] Figure 8 Also depicted is an embodiment of a wafer handling system 890 for transferring wafers within the processing chamber 814. In some embodiments, the wafer handling system 890 can transfer wafers between various processing stations and / or between a processing station and a load lock. It should be understood that any suitable wafer handling system can be used. Non-limiting examples include a wafer turntable and a robot for handling wafers. Figure 8 Also depicted is an embodiment of a system controller 850 for controlling process conditions and hardware states of the processing tool 800. The system controller 850 may include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. The processor 852 may include a CPU or computer, analog and / or digital input / output connections, a stepper motor controller board, etc.

[0081] In some embodiments, the system controller 850 controls all activities of the processing tool 800. The system controller 850 executes system control software 858 stored in the mass storage device 854, loaded into the memory device 856, and executed on the processor 852. The system control software 858 can include instructions for controlling timing, mixing of gases, chamber and / or station pressures, chamber and / or station temperatures, purge conditions and timing, wafer temperature, RF power level, RF frequency, substrate, pedestal, chuck and / or pedestal position, and other parameters of the specific processing performed by the processing tool 800. The system control software 858 can be configured in any suitable manner. For example, various processing tool component subroutines or control objects can be written to control the operation of the processing tool components necessary to perform various processing tool processes according to the disclosed methods. The system control software 858 can be encoded in any suitable computer-readable programming language.

[0082] In some embodiments, the system control software 858 may include input / output control (IOC) sequencing instructions for controlling the various parameters described above. For example, each stage of the ALD process may include one or more instructions for execution by the system controller 850. Instructions for setting process conditions for the ALD process stage may be included in the corresponding ALD recipe stage. In some embodiments, the ALD recipe stages may be arranged sequentially so that all instructions for the ALD process stage are executed simultaneously with the process stage.

[0083] In some embodiments, other computer software and / or programs stored on the mass storage device 854 and / or the memory device 856 associated with the system controller 850 may be employed. Examples of programs or program segments used for this purpose include substrate positioning programs, process gas control programs, pressure control programs, heater control programs, and plasma control programs.

[0084] The substrate positioning program may contain program code for processing tool components used to load a substrate into the pedestal 818 and control the spacing between the substrate and other parts of the processing tool 800.

[0085] The process gas control program may include code for controlling gas composition and flow rate and optionally for flowing gas into one or more process stations prior to deposition to stabilize the pressure in the process station. The process gas control program may include code for controlling gas composition and flow rate within any disclosed range. The pressure control program may include code for controlling the pressure within the process station by adjusting, for example, a throttle valve in the exhaust system of the process station, gas flow into the process station, etc. The pressure control program may include code for maintaining the pressure in the process station within any disclosed pressure range.

[0086] The heater control program may include code for controlling the flow of current to a heating unit that is used to heat the substrate. Alternatively, the heater control program may control the delivery of a heat transfer gas (e.g., helium) to the substrate. The heater control program may include instructions for maintaining the temperature of the substrate within any disclosed range.

[0087] The plasma control program may include code for setting the RF power level and frequency applied to the processing electrodes in one or more processing stations, for example using any RF power level disclosed herein. The plasma control program may also include code for controlling the duration of each plasma exposure.

[0088] In some embodiments, there may be a user interface associated with the system controller 850. The user interface may include a display screen, a graphical software display of apparatus and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, and the like.

[0089] In some embodiments, the parameters adjusted by the system controller 850 may relate to process conditions. Non-limiting examples include process gas composition and flow rate, temperature, pressure, plasma conditions (e.g., RF power level, frequency, and exposure time), etc. These parameters may be provided to the user in the form of a recipe, which may be entered using the user interface.

[0090] Signals for monitoring the process may be provided from various process tool sensors by analog and / or digital input connections of the system controller 850. Signals for controlling the process may be output through analog and / or digital output connections of the process tool 800. Non-limiting examples of process tool sensors that may be monitored include mass flow controllers, pressure sensors (e.g., manometers), thermocouples, etc. Appropriately programmed feedback and control algorithms may be used with the data from these sensors to maintain process conditions.

[0091] Any suitable chamber may be used to implement the disclosed embodiments. Exemplary deposition equipment includes, but is not limited to, product series, or any of a variety of other commercially available processing systems, wherein The product family is available from Lam Research Corp. of Fremont, California. Two or more stations may perform the same function. Similarly, two or more stations may perform different functions. Each station may be designed / configured as needed to perform a specific function / method.

[0092] Fig. 9900 is a block diagram of a processing system suitable for performing a thin film deposition process according to certain embodiments. System 900 includes a transfer module 903. The transfer module 903 provides a clean, pressurized environment to minimize the risk of contamination when the substrate being processed moves between the various reactor modules. According to certain embodiments, mounted on the transfer module 903 are two multi-station reactors 909 and 910, each reactor capable of performing atomic layer deposition (ALD) and / or chemical vapor deposition (CVD). Reactors 909 and 910 may include multiple stations 911, 913, 915, and 917, which may perform operations sequentially or non-sequentially according to the disclosed embodiments. These stations may include a heated pedestal or substrate support, one or more gas inlets or nozzles, or a dispersion plate.

[0093] Mounted on the transfer module 903 may also be one or more single or multi-station modules 907 that are capable of performing plasma or chemical (non-plasma) pre-cleaning, or any other process associated with the disclosed method. In some cases, the module 907 may be used for various processes, such as preparing a substrate for a deposition process. The module 907 may also be designed / configured to perform various other processes, such as etching or polishing. The system 900 also includes one or more wafer source modules 901, in which wafers are stored before and after processing. An atmospheric manipulator (not shown) in the atmospheric transfer chamber 919 may first move the wafer from the source module 901 to the load lock 921. The wafer transfer device (typically a robot unit) in the transfer module 903 moves the wafer from the load lock 921 to the module mounted on the transfer module 903 and to the module mounted on the transfer module 903.

[0094] In various embodiments, the system controller 929 is used to control process conditions during the deposition process. The controller 929 will typically include one or more memory devices and one or more processors. The processor may include a CPU or calculator, analog and / or digital input / output connections, a stepper motor controller board, and the like.

[0095] The controller 929 can control all of the activities of the deposition apparatus. The system controller 929 executes system control software, which includes a set of instructions for controlling timing, mixtures of gases, chamber pressure, room temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Other computer programs stored in a memory device associated with the controller 929 may be employed in some embodiments.

[0096] There will typically be a user interface associated with the controller 929. The user interface may include a display screen, a graphical software display of the apparatus and / or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, and the like.

[0097] The system control logic can be configured in any suitable manner. In general, the logic can be designed or configured in hardware and / or software. The instructions for controlling the drive circuit can be hard-coded or provided as software. The instructions can be provided by "programming". Such programming is understood to include any form of logic, including hard-coded logic 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 that can be executed on a general-purpose processor. The system control software can be encoded in any suitable computer-readable programming language.

[0098] The computer program code for controlling the germanium-containing reducing agent pulses, hydrogen gas flow, and tungsten-containing precursor pulses, as well as other processes in the process sequence, can be written in any commonly used computer-readable programming language: for example, assembly language, C, C++, Pascal, Fortran, or others. The compiled object code or script is executed by the processor to perform the tasks identified in the program. Also as indicated, the program code can be hard-coded.

[0099] Controller parameters are related to process conditions such as, for example, process gas composition and flow rate, temperature, pressure, cooling gas pressure, substrate temperature, and chamber wall temperature. These parameters are provided to the user in the form of recipes and can be input using the user interface. Signals for monitoring the process can be provided through analog and / or digital input connections of the system controller 929. Signals for controlling the process are output through analog and digital output connections of the deposition apparatus 900.

[0100] The system software may 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 chamber components necessary to perform deposition processes (and in some cases other processes) in accordance with the disclosed embodiments. Examples of programs or program segments for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

[0101] In some implementations, the controller 929 is part of a system that can be part of the above-described embodiments. Such a system can include a semiconductor processing device that includes one or more processing tools, one or more processing chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems can be integrated with electronic devices for controlling their operations before, during, and after processing semiconductor wafers or substrates. The electronic device can be referred to as a "controller," which can control various components or subcomponents of one or more systems. Depending on the processing requirements and / or the type of system, the controller 929 can be programmed to control any process disclosed herein, including controlling process gas delivery, 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 delivery settings, position and operation settings, wafer transfer in and out of tools and other transfer tools and / or load locks connected to or connected to a specific system through an interface.

[0102] In a broad sense, a controller can be defined as an electronic device with various integrated circuits, logic, memory and / or software that receives instructions, issues instructions, controls operations, enables cleaning operations, enables endpoint measurements, etc. The integrated circuit can include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors or microcontrollers that execute program instructions (e.g., software). The program instructions can be instructions transmitted to the controller in the form of various separate settings (or program files), which define operating parameters for performing specific processing on or for a semiconductor wafer or system. In some embodiments, the operating parameters can be part of a recipe defined by a process engineer for completing one or more processing steps during the preparation of one or more (kinds) of layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0103] In some implementations, the controller may be part of or coupled to a computer that is integrated with, coupled to, or connected to the system or a combination thereof via a network. For example, the controller may be in the "cloud" or all or part of a wafer fab host system, thereby allowing remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of a manufacturing operation, check the history of past manufacturing operations, check trends or performance criteria for multiple manufacturing operations, change parameters of a current process, set processing steps to follow the current process, or start a new process. In some embodiments, a remote computer (e.g., a server) may provide a process recipe to the system via a network, which may include a local network or the Internet. The remote computer may include a user interface that allows input or programming of parameters and / or settings, which are then transmitted from the remote computer to the system. In some embodiments, the controller receives instructions in the form of data that specify parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be for the type of process to be performed and the type of tool to which the controller is configured to connect or control the tool type. Thus, as described above, the controller may be distributed, for example, by including one or more discrete controllers that are networked together and work toward a common goal (e.g., the processes and controls described herein). An embodiment of a distributed controller for these purposes may be one or more integrated circuits on the chamber that communicate with one or more remote integrated circuits (e.g., at a platform level or as part of a remote computer) that are combined to control the processes within the chamber.

[0104] Example systems may include, but are not limited to, plasma etch chambers or modules, deposition chambers or modules, spin cleaning chambers or modules, metal plating chambers or modules, cleaning chambers or modules, chamfer edge etch chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etch (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing system that may be associated with or used in the preparation and / or manufacture of semiconductor wafers.

[0105] As described above, depending on the process step or steps to be performed by the tool, the controller may communicate with one or more of: other tool circuits or modules, other tool components, combination tools, other tool interfaces, adjacent tools, adjacent tools, tools located throughout the factory, a host computer, another controller, or a material handling tool used in moving containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing facility.

[0106] Further implementation plans

[0107] The apparatus and processes described herein can be used in conjunction with photolithographic patterning tools or processes, for example, for preparing or manufacturing semiconductor devices, displays, LEDs, photovoltaic panels, etc. Typically, although not necessarily, these apparatus and processes will be used or operated together in a common manufacturing facility. The photolithographic patterning of a film typically includes some or all of the following steps, each of which enables multiple available tools: (1) applying a photoresist to a workpiece, i.e., a substrate, using a spin coating or spray coating tool; (2) curing the photoresist using a hot plate or heating furnace or a UV curing tool; (3) exposing the photoresist to visible light or ultraviolet light or x-rays using a tool such as a wafer stepper; (4) developing the resist to selectively remove the resist and thereby pattern it using a tool such as a wet bench; (5) transferring the resist pattern to an underlying film or workpiece by using a dry or plasma assisted etching tool; and (6) removing the resist using a tool such as an RF or microwave plasma resist stripper.

Claims

1. A method for forming a carbon layer on a surface of a semiconductor substrate in a processing chamber, the method comprising: (a) introducing an aluminum-containing reactant into the process chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond; (b) introducing a carbon-containing reactant into the process chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and wherein the carbon-containing reactant is different from the aluminum-containing reactant; (c) adsorbing at least one of the aluminum-containing reactant and the carbon-containing reactant onto the surface of the semiconductor substrate under conditions such that one or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-restricted layer on the surface of the semiconductor substrate; as well as (d) reacting the aluminum-containing reactant with the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate after at least one of the aluminum-containing reactant and the carbon-containing reactant has formed an adsorption-limited layer on the surface of the semiconductor substrate.

2. The method of claim 1, wherein the aluminum-containing reactant having at least one aluminum-carbon bond is a trialkylaluminum.

3. The method of claim 1, wherein the aluminum-containing reactant having at least one aluminum-carbon bond is trimethylaluminum.

4. The method of claim 1, wherein the carbon-containing reactant having at least one carbon-halogen bond is a carbon tetrahalide. The method of claim 1 , wherein the at least one carbon-halogen bond is a carbon-fluorine bond.

6. The method according to claim 1, wherein: The aluminum-containing reactant is a trialkylaluminum, and the carbon-containing reactant is selected from the group consisting of CX4, CHX3, CH2X2 and CH3X, wherein X is a halogen.

7. The method of claim 6, wherein X is fluorine.

8. The process according to claim 6, wherein X is chlorine and / or bromine.

9. The method of claim 1, wherein reacting the aluminum-containing reactant with the carbon-containing reactant comprises forming an aluminum-containing byproduct, wherein the method further comprises removing the aluminum-containing byproduct after (d).

10. The method of claim 9, wherein the aluminum-containing byproduct comprises an aluminum-halogen bond.

11. The method according to claim 1, wherein: The surface of the semiconductor substrate on which the carbon layer is formed has patterned three-dimensional features.

12. The method according to claim 1, wherein: The aluminum-containing reactant forms an adsorption limiting layer prior to the introduction of the carbon-containing reactant.

13. The method according to claim 1, wherein: The carbon-containing reactant forms an adsorption limiting layer prior to the introduction of the aluminum-containing reactant.

14. The method of claim 1, further comprising, between steps (a) and (b), purging and / or pumping the process chamber to remove the aluminum-containing reactant or the carbon-containing reactant from the process chamber.

15. The method according to claim 1, further comprising repeating operations (a)-(d) to deposit the carbon layer to a predetermined thickness.

16. The method according to claim 1, wherein: The carbon layer is deposited in a gap-fill operation.

17. The method of claim 1, wherein the carbon layer is deposited in a partially fabricated 3D NAND structure in a gap fabrication operation.

18. A method of forming a carbon layer on a surface of a semiconductor substrate in a processing chamber, the method comprising: (a) introducing an aluminum-containing reactant into the process chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond and forms a layer of the aluminum-containing reactant on the surface of the semiconductor substrate; (b) removing the aluminum-containing reactant from the process chamber after (a); (c) introducing a carbon-containing reactant into the process chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and wherein the carbon-containing reactant is different from the aluminum-containing reactant, and forming the carbon-containing reactant in a layer on the surface of the semiconductor substrate; (d) removing the carbon-containing reactant from the process chamber after (c); as well as (e) contacting the semiconductor substrate having the layered carbon-containing reactant and the layered aluminum-containing reactant with plasma to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant, thereby forming a carbon layer on a surface of the semiconductor substrate.

19. The method according to claim 18, wherein: The aluminum-containing reactant is a trialkylaluminum, the carbon-containing reactant is CF4, and the reaction between the trialkylaluminum and CF4 is activated by contacting the semiconductor substrate with a plasma formed in a process gas comprising a gas selected from the group consisting of helium (He), argon (Ar), hydrogen (H2) and nitrogen (N2).

20. A partially fabricated semiconductor substrate, wherein the semiconductor substrate comprises a plurality of carbon spacers.

21. A system for processing a semiconductor substrate, the system comprising: (a) a process chamber having a substrate holder and one or more inlets for introducing reactants into the process chamber; and (b) a system controller including program instructions for: (i) causing an aluminum-containing reactant to be introduced into the process chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond; (ii) causing a carbon-containing reactant to be introduced into the process chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and wherein the carbon-containing reactant is different from the aluminum-containing reactant; (iii) adsorbing at least one of the aluminum-containing reactant and the carbon-containing reactant onto the surface of the semiconductor substrate under conditions such that one or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limited layer on the surface of the semiconductor substrate; as well as (iv) causing the aluminum-containing reactant to react with the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate after at least one of the aluminum-containing reactant and the carbon-containing reactant has formed an adsorption limited layer on the surface of the semiconductor substrate.

Images