JP7396998B2 - Atomic layer deposition of carbon films - Google Patents

Description

INCORPORATION BY REFERENCE A PCT application is filed concurrently with this specification as part of this application. Each application identified in this co-filed PCT application and to which this application claims benefit or priority is incorporated herein by reference in its entirety for all purposes.

TECHNICAL FIELD The present invention relates to a method of semiconductor device manufacturing. Specifically, embodiments of the invention relate to methods of depositing carbon films in semiconductor processing.

In integrated circuit (IC) fabrication, deposition and etching techniques are used to pattern materials, such as forming metal lines embedded in dielectric layers. Some patterning methods require conformal deposition of material, and the deposited layer needs to follow the contours of protrusions and/or recessed features on the substrate surface. Atomic layer deposition (ALD) is often the preferred method of forming conformal films on substrates. This is because ALD relies on the adsorption of one or more reactants onto the substrate surface and the subsequent chemical transformation of the adsorbed layer into the desired material. Because the reactions utilized by ALD occur at the substrate surface and are typically limited by the amount of adsorbed reactants, they can provide thin conformal layers with excellent step coverage.

The background description provided herein is for the purpose of generally presenting the subject matter of the disclosure. Work by the presently named inventors to the extent described in this Background section, as well as aspects of the description that could not otherwise be considered as prior art at the time of filing, are expressly or impliedly excluded. Regardless, it is not admitted as prior art to the present disclosure.

No method has been developed to date to deposit carbon layers by ALD. Therefore, the deposition of carbon layers with highly controlled deposition thickness and good step coverage presents a difficult problem. Provided herein are methods and apparatus for depositing carbon layers with surface control. Conformal carbon films with excellent step coverage can be deposited by the provided method, both in gap fills (e.g. in 3D NAND structures) and during spacer formation in self-aligned double patterning (SADP). It can be used for various purposes such as.

In one aspect, a method of forming a carbon layer on a surface of a semiconductor substrate in a processing chamber is provided. The method includes (a) introducing into a processing chamber an aluminum-containing reactant having at least one aluminum-carbon bond (e.g., an alkyl-substituted aluminum, such as a trialkylaluminium); and (b) at least one carbon-halogen (c) either the aluminum-containing reactant or the carbon-containing reactant; or (d) adsorbing at least one of the aluminum-containing reactant and the carbon-containing reactant to the surface of the semiconductor substrate under conditions where both form an adsorption-limiting layer on the surface of the semiconductor substrate; after the at least one carbon-containing reactant forms an adsorption limiting layer on the surface of the semiconductor substrate, reacting the aluminum-containing reactant with the carbon-containing reactant to form a layer of carbon on the surface of the semiconductor substrate. Operations (a) to (d) can be repeated as many times as necessary to deposit a carbon layer with a predetermined thickness.

Suitable aluminum-containing reactants include trialkylaluminums. In one example, the aluminum-containing reactant is trimethylaluminum. Examples of suitable carbon-containing reactants with carbon-halide bonds include CX ₄ , CHX ₃ , CH ₂ X ₂ , and CH ₃ X, where X is halogen. In some embodiments, the carbon-containing reactant is a carbon tetrahalide. In some embodiments, the carbon-containing reactant includes carbon-fluorine bonds.

In one embodiment, the aluminum-containing reactant is a trialkylaluminum and the carbon-containing reactant is one or more of _CX4 , _CHX3 , _{CH2X2 ,} and _CH3X , where X is halogen. In some embodiments, the halogen is fluorine. In other embodiments, the halogen is chlorine and/or bromine. In specific examples, the aluminum-containing reactant is trialkylaluminum (eg, trimethylaluminum or triethylaluminum) and the carbon-containing reactant is _CF4 , _CCl4 , or _CBr4 .

The reaction between the aluminum-containing reactant and the carbon-containing reactant forms an aluminum-containing byproduct, which can be removed after the reaction is complete. By-products typically include aluminum-halogen bonds. For example, if the carbon-containing reactant contains carbon-fluorine bonds, the by-product will contain aluminum fluoride.

The introduction of reactants into the processing chamber is continuous, 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 aluminum-carbon bonds is first introduced into the processing chamber and an adsorption limiting layer is formed on the surface of the substrate. Unadsorbed aluminum-containing reactants are then removed from the processing chamber (e.g., by purging and/or evacuation), and a carbon-containing reactant is subsequently introduced into the processing chamber and reacted with the adsorbed layer of aluminum-containing reactants. Forms a carbon layer. The aluminum-containing by-product can then be removed. This process can be repeated as many times as necessary to deposit a carbon layer of a given thickness.

In another embodiment, the process begins by first introducing a carbon-containing reactant into the processing chamber and forming an adsorption-limiting layer of the carbon-containing reactant on the substrate. Unadsorbed carbon-containing reactants are removed from the processing chamber by purging and/or evacuation. An aluminum-containing reactant is then introduced into the processing chamber and reacts with the adsorbed layer of carbon-containing reactant to form a carbon layer on the surface of the substrate.

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 a layer of aluminum-containing reactant and a layer of carbon-containing reactant formed thereon. In one embodiment, the carbon deposition method adsorbs both the aluminum-containing reactant and the carbon-containing reactant onto the substrate surface, and includes helium (He), argon (Ar), hydrogen (H ₂ ), and nitrogen (N ₂ ). activating reactions on the substrate between adsorbed reactants by exposing the substrate to a plasma formed with a process gas comprising a gas selected from the group consisting of:

In one exemplary embodiment, a method of forming a carbon layer on a surface of a semiconductor substrate in a processing chamber by plasma activation includes: (a) an aluminum-containing reactant having at least one aluminum-carbon bond in the processing chamber; (b) removing the aluminum-containing reactant from the processing chamber after (a); and (c) at least one carbon-halogen. (d) after (c) introducing a carbon-containing reactant having a bond and different from the aluminum-containing reactant into the processing chamber and forming a layer of the carbon-containing reactant on the surface of the semiconductor substrate; (e) contacting a semiconductor substrate having a layer of carbon-containing reactant and a layer of aluminum-containing reactant with a plasma to combine the aluminum-containing reactant and the carbon-containing reactant; activating a reaction between carbon atoms, thereby forming a layer of carbon on the surface of the semiconductor substrate. Operations (a) to (e) can be repeated as many times as necessary to deposit a carbon layer of the desired thickness. In one example, the aluminum-containing reactant is trialkylaluminium, the carbon-containing reactant is _CF4 , and the reaction between the trialkylaluminum and _CF4 includes helium (He), argon (Ar), hydrogen (H ₂ ) and nitrogen (N ₂ ) by contacting the semiconductor substrate with a plasma formed with a process gas containing a gas selected from the group consisting of nitrogen (N 2 ) and nitrogen (N 2 ).

In some embodiments, the surface of the semiconductor substrate on which the carbon layer is formed has patterned three-dimensional features. In some embodiments, the carbon layer is deposited in a gap-fill operation .

For example, a carbon layer can be deposited in a gap-fill operation on a partially fabricated 3D NAND structure.

In some embodiments, a carbon layer is conformally deposited over a semiconductor substrate having a plurality of convex features. In one embodiment, the method includes completely removing the carbon layer from the horizontal surface of the convex feature without completely removing the carbon layer present on the sidewall of the convex feature; The method further includes removing the raised features without completely removing the existing carbon layer, thereby forming carbon spacers on the semiconductor substrate.

In some embodiments, a method provided includes applying a photoresist to a substrate, exposing the photoresist, patterning the photoresist to transfer the pattern to the substrate, and removing the photoresist from the substrate. and selectively removing.

In another aspect, a partially fabricated semiconductor substrate is provided. The semiconductor substrate includes a plurality of carbon spacers.

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 performing any of the methods described herein. a system controller containing program instructions for the system; In one embodiment, program instructions cause (i) an aluminum-containing reactant having at least one aluminum-carbon bond to be introduced into the processing chamber; and (ii) an aluminum-containing reactant having at least one carbon-halogen bond and having an aluminum-containing (iii) introducing a carbon-containing reactant different from the reactant into the processing chamber; after at least one of the aluminum-containing reactant and the carbon-containing reactant is adsorbed onto the surface of the semiconductor substrate, and (iv) the at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limiting layer on the surface of the semiconductor substrate. , includes instructions for reacting an aluminum-containing reactant and a carbon-containing reactant to form a layer of carbon on a surface of a semiconductor substrate.

These and other aspects of implementations of the subject matter described herein are set forth in the accompanying drawings and the description below.

FIG. 1 is a process flow diagram of a carbon deposition method according to one embodiment provided herein.

FIG. 2A is a process flow diagram of a carbon deposition method according to one embodiment provided herein.

FIG. 2B is a process flow diagram of a carbon deposition method according to another embodiment provided herein.

FIG. 3A is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein. FIG. 3B is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein. FIG. 3C is a schematic cross-sectional view of a semiconductor substrate undergoing processing according to one embodiment provided herein. FIG. 3D is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein. FIG. 3E is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein. FIG. 3F is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein.

FIG. 4 is a process flow diagram of a method of forming carbon spacers according to one embodiment provided herein.

FIG. 5 is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein. FIG. 6 is a schematic cross-sectional view of a semiconductor substrate undergoing processing in accordance with one embodiment provided herein.

FIG. 7 is a schematic diagram of an apparatus suitable for depositing carbon films according to one embodiment provided herein.

FIG. 8 is a schematic diagram of a multi-station processing system according to one embodiment provided herein.

FIG. 9 is a schematic diagram of a multi-station processing system according to one embodiment provided herein.

A method of depositing carbon films using ALD is provided. These methods are used, for example, to deposit conformal carbon films on semiconductor substrates with three-dimensional structures on the surface (such as on substrates with one or more recessed features or one or more protrusions). be able to. In some embodiments, these methods involve a reaction between an aluminum-containing reactant having an Al-C bond (e.g., trialkylaluminum) and a carbon-containing reactant having a carbon-halogen bond (e.g., CF ₄ ). Contains reactions.

As used herein, the term "ALD" generally refers to a deposition method that relies on a reaction that is limited by the amount of reactant adsorbed to the substrate surface (an adsorption-limiting reactant layer). The reactant adsorption limiting layer may include an aluminum-containing reactant adsorption limiting layer, a carbon containing reactant adsorption limiting layer, or both reactant adsorption limiting layers. In some embodiments, the ALD method includes continuously introducing reactants into a processing chamber such that the reactants do not mix in a majority of the processing chamber.

In some embodiments, carbon films are deposited in gap fill applications. For example, in one embodiment, a carbon film can be deposited in a gap fill during 3D NAND fabrication. In some implementations, carbon films are used as spacers in self-aligned double patterning (SADP). However, the provided method is not limited to depositing carbon films on surfaces with concave features, but can also be used to deposit blanket carbon films on flat surfaces. This method relies on surface-controlled reactions and can be used to deposit films with a high degree of control over film thickness. Film deposition can be performed in a wide variety of devices that allow reactants to be continuously introduced into the process chamber. For example, carbon film deposition can be performed in a Striker® deposition system available from Lam Research Corporation.

Carbon, as used herein, refers to a material consisting essentially of carbon (C) and optionally containing hydrogen (H). In some embodiments, carbon films used herein may include C--H bonds. Hydrocarbon-containing materials are within the scope of carbon membranes. The carbon film may also have small amounts of other elements as dopants, less than about 10 atomic percent of the total amount of dopants (hydrogen is not included in this calculation).

As used herein, the term "semiconductor substrate" refers to a substrate at any stage of semiconductor device fabrication that includes semiconductor material anywhere within its structure. Note that there is no need to expose the semiconductor material in the semiconductor substrate. A semiconductor wafer having multiple layers of other materials (eg, dielectrics) overlying semiconductor material is an example of a semiconductor substrate. The detailed description below assumes that the disclosed embodiments are implemented on a wafer. However, the disclosed embodiments are not so limited. Workpieces can be of various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that can utilize the disclosed embodiments include various products such as printed circuit boards.

A process for depositing a carbon film is illustrated by the process flow diagram shown in FIG. 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 (eg, n-propyl or iso-propyl), butyl, pentyl, and the like. In some embodiments, the aluminum-containing reactant is a trialkylaluminum. Examples of suitable reactants include trimethylaluminum, triethylaluminum, and the like. In some embodiments, the aluminum-containing reactant is volatile and is introduced into the processing chamber in a gas phase. The reactants can be introduced in a mixture with a carrier gas, which is typically an inert gas such as _N2 , He, Ar, Ne, or Kr. When the aluminum-containing reactant is not volatile, it can be vaporized using a direct liquid injection (DLI) vaporizer, such as the Vapbox DLI vaporizer available from Kemstream.

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 bond, a carbon-chlorine bond, and a carbon-bromine bond. Examples of suitable reactants include _CX4 , _CHX3 , _{CH2X2 ,} and _CH3X , where X is halogen. For example, some embodiments use fluorine-containing reactants such as _CF4 , _CHF3 , _{CH2F2 ,} or _CH3F . In other embodiments, chlorine-containing reactants such as _CCl4 , _CHCl3 , _{CH2Cl2 ,} or _CH3Cl may be used.

The aluminum-containing reactant and the carbon-containing reactant are typically introduced into the processing chamber sequentially and do not mix in the majority of the processing chamber. The order of introduction may vary depending on the embodiment. In some embodiments, the aluminum-containing reactant is introduced first followed by the carbon-containing reactant. In other embodiments, the carbon-containing reactant is introduced first followed by the aluminum-containing reactant. At least one of the reactants (eg, an aluminum-containing reactant, a carbon-containing reactant, or both) forms an adsorption-limiting layer on the substrate. In some embodiments, the first introduced reactant forms an adsorption limiting layer on the substrate, and the second introduced reactant forms an adsorption limiting layer on the substrate after contacting the adsorption limiting layer of the first reactant. Reacts with the adsorption limiting layer. In other embodiments, the first introduced reactant forms an adsorption-limiting layer, the second introduced reactant also forms an adsorption-limiting layer, and then (e.g., after thermal activation or plasma activation) ), both reactants react at the substrate surface. In some embodiments, the reaction involves contacting the substrate with a plasma formed with a gas such as helium (He), argon (Ar), hydrogen ( _H2 ) and nitrogen ( _N2 ), or any mixture thereof. activated by Activation of the reaction by plasma can be used to enable the formation of carbon at relatively low temperatures. In some embodiments, the carbon film is formed using a plasma activated reaction at a temperature of less than 300°C, such as less than 200°C.

Regardless of the order of introduction, in some embodiments, the introduction of the first reactant is followed by the introduction of the second reactant to remove unadsorbed reactants that were introduced first from the processing chamber. purge and/or evacuate the processing chamber beforehand.

In operation 105, the aluminum-containing reactant reacts with the carbon-containing reactant to form a layer of carbon on the substrate surface. In this case, the amount of carbon formed is limited by an adsorption limiting layer of reactants (eg, aluminum-containing reactants and/or carbon-containing reactants). In this reaction, the aluminum-carbon bonds in the aluminum-containing reactant and the carbon-halogen bonds in the carbon-containing reactant are cleaved to form carbon (which may contain C-H bonds) and byproducts containing aluminum-halogen bonds. Form. For example, when the halogen in the carbon-containing reactant is fluorine, byproducts containing aluminum-fluorine bonds are formed. In some embodiments, the reaction occurs spontaneously after contacting the reactants. In other embodiments, the reaction is activated (eg, thermally) after contacting the reactants.

In some embodiments, aluminum halide byproducts are removed from the substrate surface simultaneously with carbon formation. In other embodiments, the aluminum-containing byproduct is removed from the substrate in a separate step, as illustrated by operation 107. For example, the substrate can be heated to remove volatile aluminum halides (eg, aluminum fluoride) byproducts.

The deposition cycle including operations 101-105, in some embodiments, deposits an average of 0.5-3A of carbon film per cycle. This cycle can be repeated as many times as necessary to deposit a carbon film of the desired thickness. For example, in some embodiments, a carbon film between 5 and 1,000 Å thick is deposited.

One embodiment of a carbon deposition method is illustrated by the process flow diagram shown in FIG. 2A. The process begins at 201 with adsorption of an aluminum-containing reactant onto a semiconductor substrate. An aluminum-containing precursor, such as trialkyl aluminum, can be flowed into the process chamber with a carrier gas and adsorbed to the substrate surface. The process conditions for this step are selected such that an adsorption limiting layer of the aluminum-containing reactant is formed. Next, in operation 203, unadsorbed aluminum-containing reactants are removed from the processing chamber by purging and/or evacuating the processing chamber. For example, the processing chamber can be purged with an inert gas such as N ₂ , He, Ar, Ne, and the like. After this step, the majority of the processing chamber is free of aluminum-containing precursors and all subsequent reactions are limited by the amount of adsorbed aluminum-containing reactants on the substrate. Next, in operation 205, a carbon-containing reactant is introduced into the processing chamber and reacts with the adsorbed aluminum-containing reactant to form a layer of carbon on the surface of the semiconductor substrate. In some embodiments, this reaction occurs spontaneously after the carbon-containing reactant is introduced.

Next, in operation 207, the aluminum-containing byproduct is removed from the processing chamber. This step is optional because in some embodiments byproducts are removed at the same time as carbon formation. If the by-products are not removed simultaneously with the carbon-forming reaction, they can be removed in a separate step (eg, by heating).

Next, in operation 209, carbon deposition (steps 201 to 207) is repeated as many times as necessary to form a carbon layer of a predetermined thickness. For example, in some embodiments, a cycle including performing acts 201-205 is repeated at least 5 times or at least 10 times. Temperature and pressure during processing are controlled to allow formation of an adsorption limiting layer of one or both reactants on the substrate. In some embodiments, the temperature is maintained below about 400° C. and the pressure is maintained at a sub-atmospheric level throughout the series of deposition operations. Deposition of carbon films using the described reactants can be carried out in the absence of a plasma. In some embodiments, plasma treatment may be utilized, for example, to improve the quality of the deposited carbon layer after deposition and/or to activate one or more reactants at the substrate surface. good.

FIG. 2B shows a process flow diagram of a method of forming a carbon layer using a plasma activated reaction. Referring to FIG. 2B, the process begins at 211 with forming a layer of aluminum-containing reactant on a substrate. For example, an adsorption limiting layer of an aluminum-containing reactant can be formed on the substrate. Next, in operation 213, the processing chamber is purged and/or evacuated to remove aluminum-containing reactants from the processing chamber. For example, an inert gas can be used as a purge gas to remove unadsorbed aluminum-containing reactants. Next, in operation 215, a layer of carbon-containing material is formed on the substrate. For example, a carbon-containing material can be introduced into the processing chamber to form an adsorption limiting layer on the substrate. In operation 217, the processing chamber is purged and/or evacuated to remove carbon-containing material from the processing chamber. After this operation, there is a layer of aluminum-containing material and a layer of carbon-containing material on the substrate surface. Next, in operation 219, the substrate is treated with a plasma to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant on the substrate to form a carbon layer. In some embodiments, the plasma is formed of helium (He), argon (Ar), hydrogen ( _H2 ), nitrogen ( _N2 ), or any mixture of these gases. Reaction byproducts can be removed simultaneously with the plasma treatment or in a subsequent step. After plasma processing, the processing chamber may be purged and/or evacuated, and the sequence of steps 211-219 may be repeated as many times as necessary in operation 221 until a carbon layer having a predetermined thickness is deposited. I can do it. In one exemplary embodiment, the aluminum-containing reactant is trialkylaluminum (eg, trimethylaluminum or triethylaluminum) and the carbon-containing reactant is _CF4 .

Carbon films deposited by the methods provided herein can be used in a variety of applications in semiconductor device fabrication. This carbon film is particularly useful when conformal deposition of the film onto a substrate having three-dimensional features (eg, convex or concave features) is desired. In some embodiments, carbon films are used as spacers in patterning applications. An example of carbon spacer formation is shown in FIGS. 3A-3F. These are schematic cross-sectional views of a semiconductor substrate at various processing stages. FIG. 4 shows an exemplary process flow diagram of a semiconductor processing method involving the formation of a carbon mandrel.

Referring to FIG. 4, the illustrated process begins at 401 with providing a substrate having a plurality of convex features, also referred to as a mandrel. FIG. 3A, which depicts an exemplary substrate, shows two mandrels 301 overlying an etch stop layer (ESL) 303. The distance d1 between adjacent mandrels is about 10-100 nm in some embodiments. In some embodiments, relatively large distances of about 40-100 nm are used. In other applications, the distance between the closest mandrels is about 10-30 nm. The distance d2 between the centers of the nearest mandrels, also referred to as pitch, is approximately 30-130 nm in some embodiments. In some embodiments, the pitch is about 80-130 nm. In other embodiments, the pitch is about 30-40 nm. The height d3 of the mandrel is typically about 20-200 nm, for example about 50-100 nm.

The mandrel and ESL materials are then selected such 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. Accordingly, the ratio of the ESL material etch rate to the carbon etch rate is greater than 1, more preferably greater than about 1.5, such as greater than about 2 for the first chemical etch. In some embodiments, the ESL material is a silicon-containing material (e.g., a silicon-containing compound such as silicon nitride) and the first chemical etch is a fluorine-based plasma etch (e.g., formed with a fluorocarbon-containing gas). plasma). In some embodiments, the ESL material is a metal oxide or metal nitride, and the first chemical etch is a halogen-based plasma etch (eg, a plasma formed with a process gas that includes a halogen). Similarly, the ratio of the mandrel material etch rate to the carbon etch rate is greater than 1, more preferably greater than about 1.5, such as greater than about 2 for the second chemical etch. In some embodiments, the mandrel material is a silicon-containing material (e.g., a silicon-containing compound) and the first chemical etch is a fluorine-based plasma etch (e.g., a plasma formed with a fluorocarbon-containing gas). be. In some embodiments, the mandrel material is a metal oxide or metal nitride, and the first chemical etch is a halogen-based plasma etch (eg, a plasma formed with a process gas that includes a halogen).

In some embodiments, the ESL material is a silicon-containing compound (eg, SiO ₂ ) or a metal oxide (eg, titanium oxide, zirconium oxide, tungsten oxide). The mandrel material may include silicon-containing compounds (eg, 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 may be different than the mandrel core. For example, in some embodiments, the mandrel is made of amorphous silicon covered with silicon oxide (eg, with a spontaneously formed thermal oxide layer). The ESL layer and mandrel are formed by one or more of physical vapor deposition (PVD), chemical vapor deposition (CVD), ALD (without plasma or with PEALD), or plasma enhanced chemical vapor deposition (PECVD). The pattern of the mandrel can be defined using photolithographic techniques. Examples of suitable ESL/mandrel combinations include (i) a silicon oxide ESL and a silicon oxide covered silicon mandrel, (ii) a silicon oxide ESL and a metal oxide mandrel, and (iii) a metal oxide ESL. and a silicon mandrel covered with silicon oxide.

Referring again to the substrate shown in FIG. 3A, ESL layer 303 overlies and is in contact with target layer 305. Target layer 305 is a layer that requires patterning. 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 ( _SiO2 ), silicon nitride (SiN), or titanium nitride (TiN). I can do it. In some embodiments, the target layer is referred to as a hardmask layer and includes a metal nitride, such as titanium nitride. Target layer 305 may be deposited by ALD (plasma-less or PEALD), CVD, or other suitable deposition technique.

A target layer 305 overlies and is in contact with a layer 307 in which a plurality of metal lines are embedded in a layer of dielectric material. In some embodiments, layer 307 is a BEOL layer.

Referring to FIG. 4, processing of the substrate continues at 403 with depositing a carbon layer on both the horizontal surfaces and sidewalls of the raised features. The carbon layer is preferably conformally deposited using the ALD method provided herein. Referring to the structure shown in FIG. 3B, a carbon layer 309 is deposited over the ESL 303 and over the mandrel 301 (including the sidewalls). In the illustrated embodiment, the carbon layer is deposited by the ALD method developed herein. In some embodiments, the carbon layer is conformally deposited to a thickness of about 5-30 nm, such as about 10-20 nm.

After the carbon layer is conformally deposited, the process continues at 405 with completely removing the carbon layer from the horizontal surfaces without completely removing the carbon layer from the sidewalls of the convex features. This etching can be performed using an oxygen-based plasma etch (eg, using a plasma formed with an oxygen-containing gas). In other embodiments, a hydrogen-based etch may be used (eg, using a plasma formed with a process gas that includes hydrogen). If the mandrel has a silicon-containing compound or metal oxide in the outer layer, a hydrogen-based etch or an oxygen-based etch can be used. The chemical etch utilized in this step should preferably be selective to both the ESL material and the outer mandrel material (i.e., the carbon etch rate for this chemical etch should be selective to both the ESL material and the outer mandrel material). (must be greater than the etch rate of the material and greater than the etch rate of the ESL material). Removal of the carbon layer from the horizontal plane is illustrated in FIG. 3C. The carbon layer 309 is etched from the horizontal plane on the ESL 303 and the mandrel 301 without being completely etched from the position where it adheres to the sidewall of the mandrel 301. This etch exposes layer 303 everywhere except near the sidewalls of mandrel 301. Additionally, this etch exposes the top of the mandrel. The resulting structure is shown in Figure 3C. After this etching, the sidewall carbon layer preferably has at least 50% (eg, at least 80% or at least 90%) of its initial height remaining. As an example, when selectively etching carbon from a mandrel covered with silicon oxide, the carbon is removed by a hydrogen-based etch (e.g., _H2 plasma etch) such that the outer material of the mandrel ( _SiO2 ) is exposed. selectively etched. Hydrogen-based etching is selective to _SiO2 . As another example, when selectively etching carbon from a metal oxide (e.g., titanium oxide) mandrel, the carbon can be etched using a hydrogen-based etch (e.g., _H2 plasma etch) or an oxygen-based etch (e.g., The _mandrel material (metal oxide) is selectively etched to expose the mandrel material (metal oxide). These chemical etches are selective to oxides of metals (such as titanium oxide) that do not form volatile hydrides.

The next step 407 includes completely removing the raised features without completely removing the carbon layer present on the sidewalls of the raised features, thereby forming carbon spacers. As shown in FIG. 3D, mandrel 301 is removed from the substrate, leaving exposed carbon spacers 309 and exposed layer ESL 303. Mandrel removal is performed by exposing the substrate to a chemical etch that selectively etches the mandrel material. Therefore, the ratio of the mandrel material etch rate to the carbon etch rate in this step is greater than 1, and more preferably greater than 1.5. Furthermore, the chemical etching used in this step, in some embodiments, is required to selectively etch the mandrel material compared to the ESL material. Various etching methods can be used, and the specific choice of chemistry will depend on the mandrel material and the ESL layer material. When the mandrel is made of amorphous silicon covered with silicon oxide, a fluorine-based chemistry (e.g., _NF3 ) is used to remove the _SiO2 layer covering the silicon mandrel 301 and the silicon mandrel 301 together. be able to. This chemical reaction is selective to carbon.

When the mandrel is a metal oxide (e.g., titanium oxide, tungsten oxide, zirconium oxide, hafnium oxide, tantalum oxide), substrate treatment may include a chlorine-based treatment to selectively remove the mandrel compared to carbon. Chemical etching (eg, BCl ₃ /Cl ₂ in a plasma) can be used. This chemistry can be used in the presence of an ESL containing silicon-containing compounds (eg, SiO ₂ , SiN, SiC).

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

In the next step, the target layer 305 is etched in all locations not protected by the ESL film 303 to expose the underlying layer 307. This etching step also removes carbon spacers 309, providing the patterned structure shown in Figure 3F. In some embodiments, the chemical etch used in this step is selected to remove both target material and carbon spacer material. In other embodiments, two different etch steps may be used to pattern target layer 305 and remove carbon spacer 309, each utilizing a different chemical reaction. Several chemical etches can be used depending on the chemistry of the target layer. In one embodiment, target layer 305 is a metal nitride layer (eg, a TiN layer) . In this embodiment, the metal nitride layer can be etched by exposing the substrate to a plasma formed with a process gas containing _Cl2 and hydrocarbons (e.g., _CH4 ), followed by an oxygen-based plasma chemistry. Remove the carbon spacer using etching or hydrogen-based plasma chemical etching.

In some embodiments, provided carbon deposition methods are used in gap fill applications. In gap fill, a substrate containing one or more recessed features is provided to a processing chamber and carbon is deposited by the provided method to cover both the bottom and sidewalls of the recessed features. Deposition cycles are performed as many times as necessary to fill the recessed features with carbon. Due to the highly conformal nature of this deposition, in some embodiments a seamless gap fill can be achieved. The methods provided are particularly useful for depositing carbon on high aspect ratio features. In some embodiments, the aspect ratio of the concave features is at least 5:1 (eg, at least 10:1).

In one example, carbon is used for gap fill in a 3D NAND fabrication process. In one implementation, a partially fabricated 3D NAND structure having at least one concave feature is provided to a process chamber, and the at least one concave feature is injected with carbon using the methods provided herein. Deposit to fill concave features. This application is illustrated in FIGS. 5 and 6. 5 and 6 are diagrams illustrating schematic cross-sectional views of partially fabricated 3D NAND structures.

FIG. 5 is a diagram illustrating an exemplary substrate 1100 with multiple layers 1111 and 1140 alternately deposited on the substrate 1100 in a stepped pattern. In some embodiments, layer 1111 is a dielectric layer (eg, silicon oxide) and layer 1140 is a conductive layer (eg, tungsten layer). Alternatively, layers 1111 and 1140 may be different types of dielectrics, such as silicon oxide layer 1111 and silicon nitride layer 1140. Above the top layer 1140 is a hardmask layer 1110, and a sealing layer 1139 laterally seals the step pattern of alternating layers 1111 and 1140. A plurality of vias 1137 are etched into dielectric 1122 (eg, silicon oxide), with material of layer 1140 exposed at the bottoms 1139 of vias 1137, for example. Depending on the material 1140, the vias 1137 have different depths as shown in FIG. The next step is to deposit carbon into the vias 1137 in a gap fill operation using the deposition method provided herein. The resulting structure is shown in FIG. In this figure, carbon layer 1173 fills all the vias (channels), and the carbon contacts material 1140 at the bottom of the filled vias. Carbon can be used as a sacrificial material within the channels. Then, during subsequent fabrication, the carbon can be removed from the channel by, for example, an oxygen-based plasma etch or a hydrogen-based plasma etch, and the via can be filled with a conductive material.

(Device)
The carbon deposition methods described herein can be performed in a variety of equipment. A preferred apparatus includes a processing chamber, the processing chamber having one or more inlets for introducing reactants and configured to hold the substrate in place during deposition. and optionally a plasma generation mechanism configured to generate a plasma with a process gas. The apparatus may include a controller having program instructions for causing any of the method steps described herein. An example of a suitable device is the Striker® deposition device available from Lam Research Corporation.

For example, in some embodiments, the apparatus includes a controller having program instructions that include instructions for (i)-(iv): (i) an aluminum-containing reactant having at least one aluminum-carbon bond; (ii) a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant; (iii) an aluminum-containing reactant and carbon; adsorbing at least one of the aluminum-containing reactant and the carbon-containing reactant to the surface of the semiconductor substrate under conditions such that either or both of the containing reactants forms an adsorption-limiting layer on the surface of the semiconductor substrate; and (iv) After at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limiting layer on the surface of the semiconductor substrate, the aluminum-containing reactant and the carbon-containing reactant are reacted to form a layer of carbon on the surface of the semiconductor substrate. .

An example of a deposition apparatus suitable for depositing carbon according to the provided method is shown in FIG. FIG. 7 schematically depicts one embodiment of a process station 700 that may be used to deposit materials using atomic layer deposition (ALD) and/or chemical vapor deposition (CVD). Any of the CVD methods may use plasma. For simplicity, process station 700 is illustrated as a standalone process station having a process chamber body 702 for maintaining a low pressure environment. However, it will be appreciated that multiple process stations 700 may be included in a common process tool environment. Further, it will be appreciated that in some embodiments, one or more hardware parameters of process station 700 (including those described in detail below) may be adjusted programmatically by one or more computer controllers. will be done.

Process station 700 is in fluid communication with a reactant supply system 701 for supplying process gases to distribution showerhead 706 . Reactant supply system 701 includes a mixing vessel 704 for blending and/or conditioning process gases supplied to showerhead 706 . One or more mixing vessel inlet valves 720 can control the introduction of process gas into the mixing vessel 704. Similarly, showerhead inlet valve 705 can control the introduction of process gas to showerhead 706.

Some reactants, such as trimethylaluminum, can be stored in liquid form before being vaporized and delivered to the process station. For example, the embodiment of FIG. 7 includes a vaporization point 703 for vaporizing liquid reactants provided to a mixing vessel 704. In some embodiments, vaporization point 703 may be a heated vaporizer. Reactant vapors produced from such vaporizers can condense in downstream supply piping. When incompatible gases are exposed to condensed reactants, small particles may form. These small particles can clog pipes, interfere with valve operation, and contaminate substrates. Some approaches to addressing these problems involve sweeping and/or venting the supply piping to remove residual reactants. However, sweeping the supply piping can increase process station cycle time and reduce process station throughput. Accordingly, in some embodiments, the supply piping downstream of vaporization point 703 may be heat traced. In some examples, mixing vessel 704 may also be heat traced. In one non-limiting example, the piping downstream of vaporization point 703 has a temperature increase profile ranging from approximately 100° C. to approximately 150° C. in mixing vessel 704.

In some embodiments, the liquid reactant may be vaporized with a liquid injector. For example, a liquid injector can inject pulses of liquid reactant into a carrier gas stream upstream of a mixing vessel. In one scenario, a liquid injector can vaporize the reactants by flashing the liquid from a high pressure to a low pressure. In another scenario, the liquid injector may atomize the liquid into dispersed microdroplets and subsequently vaporize the microdroplets within a heated supply pipe. It will be appreciated that small droplets can vaporize faster than large droplets, reducing the delay between liquid injection and complete vaporization. The faster the vaporization, the shorter the length of piping downstream from the vaporization point 703. In one scenario, a liquid injector may be attached directly to mixing container 704. In another scenario, the liquid injector may be attached directly to the showerhead 706.

In some embodiments, a liquid flow controller can be provided upstream of vaporization point 703 to control the mass flow rate of liquid that is vaporized and delivered to process station 700. For example, a liquid flow controller (LFC) may include a thermal mass flow meter (MFM) located downstream of the LFC. The plunger valve of the LFC may then be adjusted in response to a feedback control signal provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, stabilizing the liquid flow using feedback control may take more than a second. This may extend the administration time of the liquid reactant. Thus, in some embodiments, the LFC may be dynamically switched between feedback control mode and direct control mode. In some embodiments, the LFC can be dynamically switched from feedback control mode to direct control mode by disabling the LFC's sense tube and PID controller.

Showerhead 706 distributes process gas toward substrate 712 . In the embodiment shown in FIG. 7, substrate 712 is shown positioned below showerhead 706 and resting on pedestal 708. In the embodiment shown in FIG. It will be appreciated that the showerhead 706 can have any suitable shape and have any suitable number and arrangement of ports for distributing process gases to the substrate 712.

In some embodiments, microvolume 707 is located below showerhead 706. By conducting ALD and/or CVD processes in microvolumes rather than the entire volume of a process station, reducing exposure and sweep times to reactants and time to change process conditions (e.g., pressure, temperature, etc.) It is possible to shorten the process time and limit the exposure of process station robots to process gases. Exemplary microvolume sizes include, but are not limited to, volumes of 0.1 liters to 2 liters. This small volume also affects productivity throughput. While the deposition rate per cycle is reduced, the cycle time is simultaneously reduced. In certain cases, the latter effect is significant enough to improve the overall throughput of the module for a given target thickness of membrane.

In some embodiments, pedestal 708 can be raised or lowered to expose substrate 712 to microvolume 707 and/or to change the volume of microvolume 707. For example, during the substrate transfer stage, the pedestal 708 may be lowered so that the substrate 712 can be placed on the pedestal 708. During the deposition process stage, pedestal 708 may be raised and substrate 712 may be positioned within microvolume 707. In some embodiments, microvolume 707 can completely surround substrate 712 and a portion of pedestal 708, creating a region of high flow impedance during the deposition process.

Optionally, pedestal 708 can be lowered and/or raised during portions of the deposition process to adjust process pressure, reactant concentration, etc. within microvolume 707. In one scenario where the process chamber body 702 maintains a base pressure during the deposition process, the microvolume 707 can be evacuated by lowering the pedestal 708. Exemplary ratios of microvolume to process chamber volume include, but are not limited to, a volume ratio of 1:700 to 1:10. It will be appreciated that in some embodiments, the height of the pedestal can be adjusted programmatically by a suitable computer controller.

While the exemplary microvolume modifications described herein refer to a height-adjustable pedestal, in some embodiments the position of the showerhead 706 may be adjusted relative to the pedestal 708; It will be appreciated that the volume of microvolume 707 can be varied. Additionally, it will be appreciated that the vertical position of pedestal 708 and/or showerhead 706 may be changed by any suitable mechanism within the scope of this disclosure. In some embodiments, pedestal 708 may include a rotation axis for rotating the orientation of substrate 712. It will be appreciated that in some embodiments, one or more of these example adjustments may be implemented programmatically by one or more suitable computer controllers.

Returning to the embodiment shown in FIG. 7, the showerhead 706 and pedestal 708 are in electrical communication with an RF power source 714 and matching network 716 for powering the plasma. In other embodiments, an apparatus without a plasma generator is used to deposit carbon using the provided methods. In some embodiments, plasma energy may be controlled by controlling one or more of process station pressure, gas concentration, RF source power, RF source frequency, and plasma power pulse timing. For example, RF power source 714 and matching network 716 may be operated with any suitable power to form a plasma with a desired composition of radical species. Examples of suitable power are included above. Similarly, RF power source 714 may provide RF power at any suitable frequency. In some embodiments, RF power source 714 may be configured to control the high frequency RF power source and the low frequency RF power source independently of each other. Exemplary low frequency RF frequencies may include, but are not limited to, frequencies from 50 kHz to 700 kHz. Exemplary high frequency RF frequencies may include, but are not limited to, frequencies from 1.8 MHz to 2.45 GHz. It will be appreciated that any suitable parameters may be adjusted discretely or continuously to provide plasma energy for surface reactions. In one non-limiting example, plasma power may be pulsed intermittently to reduce ion bombardment with the substrate surface compared to a continuously powered plasma.

In some embodiments, the plasma may be monitored in situ by one or more plasma monitors. In one scenario, plasma power may be monitored by one or more voltage, current sensors (eg, VI probes). In another scenario, one or more optical emission spectroscopic sensors (OES) may measure plasma density and/or process gas concentration. In some embodiments, one or more plasma parameters can be adjusted programmatically based on measurements from such in situ plasma monitors. For example, OES sensors may be used in a feedback loop to provide programmable control of plasma power. It will be appreciated that in some embodiments other monitors may 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 transducers.

In some embodiments, the plasma may be controlled via input/output control (IOC) sequence instructions. In one example, instructions for setting plasma conditions for a plasma process step can be included in a corresponding plasma activation recipe step of a deposition process recipe. In some cases, process recipe steps may be arranged in sequence such that all instructions for a deposition process step are executed simultaneously with that process step. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe step that precedes a plasma processing step. For example, the first recipe step may include instructions to set the inert gas and/or reactant gas flow rates, instructions to set the plasma generator to the power set point, and a time delay for the first recipe step. May contain instructions. A subsequent second recipe step may include instructions to enable the plasma generator and a second recipe step time delay instruction. The third recipe step may include an instruction to disable the plasma generator and a third recipe step time delay instruction. It will be appreciated that these recipe steps may be further subdivided and/or repeated in any suitable manner within the scope of this disclosure.

In some embodiments, pedestal 708 may be temperature controlled via heater 710. Additionally, in some embodiments, pressure control of the deposition process station 700 may be provided by a butterfly valve 718. As shown in the embodiment of FIG. 7, butterfly valve 718 throttles the vacuum provided by a downstream vacuum pump (not shown). However, in some embodiments, pressure control of process station 700 may also be adjusted by varying the flow rate of one or more gases introduced into process station 700.

FIG. 8 shows a schematic diagram of one embodiment of a multi-station processing tool 800 that includes an inbound loadlock 802 and an outbound loadlock 804, either or both of which may include a remote plasma source. Such tools can be used to process substrates using the methods provided herein. Robot 806 is configured to transfer wafers from cassettes loaded through pod 808 to inbound load lock 802 via atmospheric port 810 at atmospheric pressure. The wafer is placed on the pedestal 812 of the inbound loadlock 802 by the robot 806, the atmospheric pressure port 810 is closed, and the loadlock is pumped down. If the inbound loadlock 802 includes a remote plasma source, the wafer may undergo remote plasma processing at the loadlock before being introduced into the processing chamber 814. Additionally, the wafer may also be heated in the inbound load lock 802 to remove moisture and adsorbed gases, for example. The chamber transfer port 816 to the processing chamber 814 is then opened and another robot (not shown) moves the wafer into the reactor and onto the pedestal of the first station shown within the reactor for processing. Place it. It should be noted that while the embodiment illustrated in FIG. 8 includes a load lock, it will be appreciated that in some embodiments the wafer may be entered directly into the process station.

The illustrated processing chamber 814 includes four process stations, numbered 1 through 4 in the embodiment shown in FIG. Each station has a heating pedestal (designated 818 for station 1) and a gas line inlet. It will be appreciated that in some embodiments, each process station may have a different purpose or multiple purposes. Although the illustrated processing chamber 814 includes four stations, it will be appreciated that processing chambers according to the present disclosure may have any suitable number of stations. For example, in some embodiments, the processing chamber may have five or more stations, and in other embodiments, the processing chamber may have three or fewer stations.

FIG. 8 also illustrates one embodiment of a wafer handling system 890 for transporting wafers within processing chamber 814. In some embodiments, wafer handling system 890 can transport wafers between various process stations and/or between process stations and load locks. It will be appreciated that any suitable wafer handling system may be used. Non-limiting examples include wafer carousels and wafer handling robots. FIG. 8 also illustrates one embodiment of a system controller 850 used to control process conditions and hardware status of process tool 800. System controller 850 may include one or more memory devices 856, one or more mass storage devices 854, and one or more processors 852. Processor 852 may include a CPU or computer, analog and/or digital input/output connections, a stepper motor controller board, and the like.

In some embodiments, system controller 850 controls all of the activities of process tool 800. System controller 850 executes system control software 858 stored in mass storage device 854 , loaded into memory device 856 , and implemented on processor 852 . System control software 858 includes timing, gas mixing, chamber and/or station pressures, chamber and/or station temperatures, purge conditions and purge timing, wafer temperature, RF power levels, RF frequency, substrate, pedestal, chuck position. and/or instructions for controlling susceptor position and other parameters of a particular process performed by process tool 800. System control software 858 may be configured in any suitable manner. For example, various process tool component subroutines or control objects may be written to control the operation of process tool components necessary to perform various process tool processes in accordance with the disclosed methods. System control software 858 may be coded in any suitable computer readable programming language.

In some embodiments, system control software 858 may include input/output control (IOC) sequence instructions to control the various parameters described above. For example, each stage of the ALD process may include one or more instructions for execution by system controller 850. Instructions for setting process conditions for an ALD process step may be included in a corresponding ALD recipe step. In some embodiments, ALD recipe steps may be arranged in sequence such that all instructions for an ALD process step are executed simultaneously with that process step.

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

The substrate positioning program may include program code for the process tool components used to load the substrate onto the pedestal 818 and control the spacing of the substrate to other portions of the process tool 800.

The process gas control program includes code for controlling gas composition and flow rates, and optionally for flowing gas to one or more process stations prior to deposition, in order to stabilize the pressure at the process station. be able to. The process gas control program can include code for controlling gas composition and flow rates within any of the disclosed ranges. The pressure control program may include code for controlling the pressure of the process station by, for example, adjusting a throttle valve of the process station's exhaust system, gas flow to the process station, and the like. The pressure control program may include code for maintaining the process station pressure within any of the disclosed pressure ranges.

The heater control program may include code for controlling the current to the heating unit used to heat the substrate. Alternatively, the heater control program can control the supply of heat transfer gas (such as helium) to the substrate. The heater control program can include instructions for maintaining the temperature of the substrate within any of the disclosed ranges.

The plasma control program includes code for setting the RF power level and frequency provided to the process electrodes of one or more process stations, e.g., using any of the RF power levels disclosed herein. can be included. The plasma control program may also include code for controlling each plasma exposure period.

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

In some embodiments, the parameters adjusted by system controller 850 may be related to process conditions. Non-limiting examples include process gas composition and flow rates, temperature, pressure, plasma conditions (such as RF power level, frequency, and exposure time), and the like. These parameters may be provided to the user in the form of a recipe and can be entered using a user interface.

Signals for monitoring the process may be provided by analog and/or digital input connections of system controller 850 from various process tool sensors. Signals for controlling the process can be output on analog and digital output connections of process tool 800. Non-limiting examples of process tool sensors that can be monitored include mass flow controllers, pressure sensors (such as pressure gauges), thermocouples, and the like. Appropriately programmed feedback and control algorithms can be used with data from these sensors to maintain process conditions.

Any suitable chamber may be used to implement the disclosed embodiments. Exemplary deposition equipment includes, but is not limited to, the Striker® product family of equipment available from Lam Research Corporation of Fremont, California, or any of a variety of other commercially available processing systems. Not done. Two or more stations may perform the same function. Similarly, two or more stations may perform different functions. Each station can be designed/configured to perform specific functions/methods as desired.

FIG. 9 is a block diagram of a processing system suitable for performing thin film deposition processes in accordance with certain embodiments. System 900 includes a transfer module 903. Transfer module 903 provides a clean pressurized environment to minimize the risk of contamination of substrates during processing as they are moved between various reactor modules. Attached to the transfer module 903 are two multi-station reactors 909 and 910, each capable of performing atomic layer deposition (ALD) and/or chemical vapor deposition (CVD) according to particular embodiments. be. Reactors 909 and 910 may include a plurality of stations 911, 913, 915, and 917 that may perform operations in accordance with disclosed embodiments in a continuous or discontinuous manner. The station may include a heated pedestal or substrate support, one or more gas inlets or showerheads or a distribution plate.

The transfer module 903 also includes one or more plasma precleans or chemical (non-plasma) precleans capable of performing a plasma preclean or a chemical (non-plasma) preclean, or any other process described in connection with the disclosed method. Multiple single or multi-station modules 907 may be installed. Module 907 may optionally be used for various processing, for example, to prepare a substrate for a deposition process. Module 907 may also be designed/configured to perform various other processes such as etching or polishing. System 900 also includes one or more wafer source modules 901 that store wafers before and after processing. An atmospheric robot (not shown) within the atmospheric transfer chamber 919 may initially remove the wafer from the source module 901 and transfer it to the load lock 921 . A wafer transfer device (typically a robotic arm unit) within transfer module 903 moves wafers from load lock 921 to and between modules attached to transfer module 903 .

In various embodiments, a system controller 929 is used to control process conditions during deposition. Controller 929 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, a stepper motor controller board, and the like.

Controller 929 can control all of the activities of the deposition device. System controller 929 provides a series of controls for controlling timing, gas mixing, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power level, wafer chuck position or pedestal position, and other parameters of a particular process. Implement system control software containing instructions. In some embodiments, other computer programs stored in a memory device associated with controller 929 may be used.

There is typically a user interface associated with controller 929. The user interface may include a display screen, a graphical software display of equipment and/or process conditions, and user input devices such as a pointing device, keyboard, touch screen, microphone, etc.

System control logic may be configured in any suitable manner. Generally, logic can be designed or constructed 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, including the hard-coded logic of 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 may be implemented on a general purpose processor. System control software may be coded in any suitable computer readable programming language.

The computer program code for controlling the germanium-containing reductant pulse, the hydrogen flow, and the tungsten-containing precursor pulse, as well as other processes in the process sequence, can be written in any conventional computer-readable programming language (e.g., assembly language, C, C++ , Pascal, Fortran, etc.). The compiled object code or script is executed by the processor to perform the tasks identified in the program. Also, as shown, the program code may be hard-coded.

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 a recipe and can be input using a user interface. Signals for monitoring the process may be provided by analog and/or digital input connections of system controller 929. Signals for controlling the process are output on analog and digital output connections of deposition apparatus 900.

System software can be designed or configured in many different ways. For example, various chamber component subroutines or control objects are written to control the operation of chamber components necessary to perform the deposition process (and possibly other processes) in accordance with the disclosed embodiments. Good too. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, and heater control code.

In some implementations, controller 929 is part of a system, and such a system may be part of the examples described above. Such systems include one or more processing tools, one or more chambers, one or more processing platforms, and/or certain processing components (wafer pedestals, gas flow systems, etc.). A processing device may be included. These systems may be integrated with electronics to control system operation before, during, and after processing of semiconductor wafers or substrates. Such electronic equipment is sometimes referred to as a "controller" and may control various components or subcomponents of one or more systems. Controller 929 may be programmed to control any of the processes disclosed herein, depending on processing requirements and/or type of system. Such processes include process gas supply, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings in some systems, and RF matching circuits. configuration, frequency settings, flow settings, fluid supply settings, position and motion settings, loading and unloading wafers into and out of tools, and into and out of other transport tools and/or load locks connected to or associated with a particular system. is included.

Broadly defined, a controller includes various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. It may be defined as an electronic device having An integrated circuit may be 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, i.e., a chip that stores program instructions. may include a microcontroller executing (e.g., software). Program instructions are instructions communicated to a controller in the form of various individual settings (or program files) to perform a particular process on or for a semiconductor wafer or to a system. operating parameters may be defined. The operating parameters, in some embodiments, implement one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or one or more processing steps in the fabrication of the wafer die. It may be part of a recipe defined by a process engineer to

The controller, in some implementations, may be part of or coupled to a computer that is integrated or coupled with or otherwise networked to the system. , or a combination thereof. For example, the controller may be in the "cloud" or may be all or part of a fab host computer system. This allows remote access to wafer processing. The computer allows remote access to the system to monitor the current progress of a fabrication operation, review the history of past fabrication operations, review trends or performance criteria from multiple fabrication operations, and monitor current processing may change the parameters of the process, set processing steps that follow the current process, or start a new process. In some examples, a remote computer (eg, a server) can provide process recipes to the system over a network. Such networks may include local networks or the Internet. The remote computer may include a user interface that allows entry or programming of parameters and/or settings that are then communicated from the remote computer to the system. In some examples, the controller receives instructions in the form of data. Such data identifies parameters for each processing step performed during one or more operations. It should be appreciated that the parameters may be specific to the type of process being performed and the type of tool that the controller is configured to interface with or control. Thus, as discussed above, a controller may be defined, for example, by comprising one or more individual controllers that are networked together and work together toward a common purpose (such as the processes and control described herein). May be distributed. An example of a distributed controller for such purposes is one or more integrated circuits on the chamber that are remotely located (e.g., at the platform level or as part of a remote computer) and that One may include one that communicates with one or more integrated circuits that are combined to control the process.

Exemplary systems include plasma etch chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, bevel 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, tracking chambers or modules, and semiconductor wafer fabrication and and/or any other semiconductor processing system that may be associated with or used in manufacturing.

As described above, depending on one or more process steps performed by the tool, the controller may be connected to one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, Used for material transport to move containers of wafers into and out of adjacent tools, adjacent tools, tools located throughout the factory, the main computer, another controller, or tool locations and/or load ports within a semiconductor manufacturing facility. may communicate with tools that are used.

(Further embodiments)
The apparatus and processes described herein may be used in conjunction with lithographic patterning tools or processes, for example, for the fabrication or manufacturing of semiconductor devices, displays, LEDs, solar panels, and the like. Typically, although not required, such equipment and processes are used or performed together in a common fabrication facility. Lithographic patterning of films generally includes some or all of the following steps, each of which is enabled using a number of available tools: (1) using spin-on or spray-on tools; (2) curing the photoresist using a hot plate or oven or a UV curing tool; (3) using a tool such as a wafer stepper. (4) developing the resist to selectively remove the resist using a tool such as a wet bench, thereby patterning the resist; (5) transferring the resist pattern to the underlying film or workpiece by using a dry etching tool or a plasma-assisted etching tool; and (6) using a tool such as an RF or microwave plasma resist stripper. step to remove the resist.
The present invention can also be realized, for example, in the following manner.
Application example 1:
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 having at least one aluminum-carbon bond into the processing chamber;
(b) introducing into the processing chamber a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant;
(c) at least one of the aluminum-containing reactant and the carbon-containing reactant under conditions such that either or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limiting layer on the surface of the semiconductor substrate; adsorbing one to the surface of the semiconductor substrate;
(d) after at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limiting layer on the surface of the semiconductor substrate, reacting the aluminum-containing reactant with the carbon-containing reactant to absorb carbon. forming a layer on the surface of the semiconductor substrate;
including methods.
Application example 2:
The method of application example 1,
The method wherein the aluminum-containing reactant having at least one aluminum-carbon bond is a trialkylaluminum.
Application example 3:
The method of application example 1,
The method wherein the aluminum-containing reactant having at least one aluminum-carbon bond is trimethylaluminum.
Application example 3:
The method of application example 1,
The method wherein the carbon-containing reactant having at least one carbon-halogen bond is a carbon tetrahalide.
Application example 4:
The method of application example 1,
The method, wherein the at least one carbon-halogen bond is a carbon-fluorine bond.
Application example 5:
The method of application example 1,
The method wherein the aluminum-containing reactant is a trialkylaluminium, and the carbon-containing reactant is selected from the group consisting of CX4 _, CHX3 _, CH2X2 _, and _CH3X , where _X is halogen.
Application example 6:
The method of application example 5,
X is fluorine, method.
Application example 7:
The method of application example 5,
A method in which X is chlorine and/or bromine.
Application example 8:
The method of application example 1,
The method wherein reacting the aluminum-containing reactant with the carbon-containing reactant includes forming an aluminum-containing by-product, the method further comprising removing the aluminum-containing by-product after (d).
Application example 9:
The method of Application Example 8,
The method wherein the aluminum-containing by-product comprises an aluminum-halogen bond.
Application example 10:
The method of application example 1,
The surface of the semiconductor substrate on which the carbon layer is formed has patterned three-dimensional features.
Application example 11:
The method of application example 1,
The method wherein the aluminum-containing reactant forms an adsorption-limiting layer prior to introducing the carbon-containing reactant.
Application example 12:
The method of application example 1,
The method wherein the carbon-containing reactant forms an adsorption-limiting layer prior to introducing the aluminum-containing reactant.
Application example 13:
The method of application example 1,
The method further comprising purging and/or evacuating the processing chamber between steps (a) and (b) to remove the aluminum-containing reactant or the carbon-containing reactant from the processing chamber.
Application example 14:
The method of application example 1,
The method further comprising repeating operations (a) to (d) to deposit the carbon layer to a predetermined thickness.
Application example 15:
The method of application example 1,
The method, wherein the carbon layer is deposited in a gap-fill operation.
Application example 16:
The method of application example 1,
The method wherein the carbon layer is deposited in a gap fill operation on a partially fabricated 3D NAND structure.
Application example 17:
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 having at least one aluminum-carbon bond into the processing chamber and forming a layer of the aluminum-containing reactant on the surface of the semiconductor substrate;
(b) removing the aluminum-containing reactant from the processing chamber after (a);
(c) introducing a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant into the processing chamber, and applying a layer of the carbon-containing reactant to the surface of the semiconductor substrate. forming a
(d) removing the carbon-containing reactant from the processing chamber after (c);
(e) contacting the semiconductor substrate having the layer of the carbon-containing reactant and the layer of the aluminum-containing reactant with a plasma to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant; , thereby forming a layer of carbon on the surface of the semiconductor substrate;
including methods.
Application example 18:
The method of Application Example 17,
The aluminum-containing reactant is trialkylaluminum, the carbon-containing reactant is CF4 _, and the reaction between the trialkylaluminum and CF4 _is performed using helium (He), argon (Ar), hydrogen (H ₂ ) and nitrogen (N2 ₎ .
Application example 19:
A partially fabricated semiconductor substrate with a plurality of carbon spacers.
Application example 20:
A system for processing a semiconductor substrate, the system comprising:
(a) a processing chamber having a substrate holder and one or more inlets for introducing reactants into the processing chamber;
(b) a system controller,
(i) introducing an aluminum-containing reactant having at least one aluminum-carbon bond into the processing chamber;
(ii) introducing into the processing chamber a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant;
(iii) at least one of the aluminum-containing reactant and the carbon-containing reactant under conditions such that either or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limiting layer on the surface of the semiconductor substrate; adsorbed on the surface of the semiconductor substrate, and
(iv) after at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limiting layer on the surface of the semiconductor substrate, the aluminum-containing reactant and the carbon-containing reactant are allowed to react; forming a layer on the surface of the semiconductor substrate;
System controller containing program instructions for
A system equipped with.

Claims (20)

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 having at least one aluminum-carbon bond into the processing chamber;
(b) introducing into the processing chamber a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant;
(c) at least one of the aluminum-containing reactant and the carbon-containing reactant under conditions such that either or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limiting layer on the surface of the semiconductor substrate; adsorbing one to the surface of the semiconductor substrate;
(d) after at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limiting layer on the surface of the semiconductor substrate, reacting the aluminum-containing reactant with the carbon-containing reactant to absorb carbon. forming a layer on the surface of the semiconductor substrate. The method according to claim 1, comprising:
The method wherein the aluminum-containing reactant having at least one aluminum-carbon bond is a trialkylaluminum. The method according to claim 1, comprising:
The method wherein the aluminum-containing reactant having at least one aluminum-carbon bond is trimethylaluminum. The method according to claim 1, comprising:
The method wherein the carbon-containing reactant having at least one carbon-halogen bond is a carbon tetrahalide. The method according to claim 1, comprising:
The method, wherein the at least one carbon-halogen bond is a carbon-fluorine bond. The method according to claim 1, comprising:
The method wherein the aluminum-containing reactant is a trialkylaluminium, and the carbon-containing reactant is selected from the group consisting of _CX4 , _CHX3 , _{CH2X2 ,} and _CH3X , where X is halogen. 7. The method according to claim 6,
X is fluorine, method. 7. The method according to claim 6,
A method in which X is chlorine and/or bromine. The method according to claim 1, comprising:
The method wherein reacting the aluminum-containing reactant with the carbon-containing reactant includes forming an aluminum-containing by-product, the method further comprising removing the aluminum-containing by-product after (d). 10. The method according to claim 9,
The method wherein the aluminum-containing by-product comprises an aluminum-halogen bond. The method according to claim 1, comprising:
The surface of the semiconductor substrate on which the carbon layer is formed has patterned three-dimensional features. The method according to claim 1, comprising:
The method wherein the aluminum-containing reactant forms an adsorption-limiting layer prior to introducing the carbon-containing reactant. The method according to claim 1, comprising:
The method wherein the carbon-containing reactant forms an adsorption-limiting layer prior to introducing the aluminum-containing reactant. The method according to claim 1, comprising:
The method further comprising purging and/or evacuating the processing chamber between steps (a) and (b) to remove the aluminum-containing reactant or the carbon-containing reactant from the processing chamber. The method according to claim 1, comprising:
The method further comprising repeating operations (a) to (d) to deposit the carbon layer to a predetermined thickness. The method according to claim 1, comprising:
The method, wherein the carbon layer is deposited in a gap-fill operation. The method according to claim 1, comprising:
The method wherein the carbon layer is deposited in a gap fill operation on a partially fabricated 3D NAND structure. 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 having at least one aluminum-carbon bond into the processing chamber and forming a layer of the aluminum-containing reactant on the surface of the semiconductor substrate;
(b) removing the aluminum-containing reactant from the processing chamber after (a);
(c) introducing a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant into the processing chamber, and applying a layer of the carbon-containing reactant to the surface of the semiconductor substrate. forming a
(d) removing the carbon-containing reactant from the processing chamber after (c);
(e) contacting the semiconductor substrate having the layer of the carbon-containing reactant and the layer of the aluminum-containing reactant with a plasma to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant; , thereby forming a layer of carbon on a surface of the semiconductor substrate. 19. The method according to claim 18,
The aluminum-containing reactant is trialkylaluminum, the carbon-containing reactant is _CF4 , and the reaction between the trialkylaluminum and _CF4 is performed using helium (He), argon (Ar), hydrogen (H ₂ ) and nitrogen ( _N2 ). A system for processing a semiconductor substrate, the system comprising:
(a) a processing chamber having a substrate holder and one or more inlets for introducing reactants into the processing chamber;
(b) a system controller,
(i) introducing an aluminum-containing reactant having at least one aluminum-carbon bond into the processing chamber;
(ii) introducing into the processing chamber a carbon-containing reactant having at least one carbon-halogen bond and different from the aluminum-containing reactant;
(iii) at least one of the aluminum-containing reactant and the carbon-containing reactant under conditions such that either or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limiting layer on the surface of the semiconductor substrate; (iv) after at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limiting layer on the surface of the semiconductor substrate, the aluminum-containing reactant a system controller comprising program instructions for reacting the carbon-containing reactant with a carbon-containing reactant to form a layer of carbon on the surface of the semiconductor substrate.

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