KR20200127261A - Atomic layer deposition of carbon films - Google Patents

Abstract

Carbon films include an aluminum-containing reactant having an aluminum-carbon bond (e.g., trialkylaluminum) and a carbon-containing reactant having a carbon-halogen bond (e.g., a fluorocarbon such as CF ₄ or CH ₂ F ₂ ) It is deposited on semiconductor substrates by atomic layer deposition using inter-reaction. The method comprises sequentially introducing reactants into a processing chamber, forming an adsorption-limited layer of one or both of the reactants on the surface of the semiconductor substrate, and carbon in an amount limited by the adsorption-limited reaction layer. It involves reacting the carbon-containing reactant and the aluminum-containing reactant to form a layer. Aluminum-containing by-products are removed from the processing chamber. These carbon layers can be used as spacers in gapfill applications, for example self-aligned double patterning processes in 3D NAND manufacturing.

Description

Atomic layer deposition of carbon films

Quoted by reference

A PCT application form was filed concurrently with this specification as part of this application. Each application claiming priority or benefit as identified in the PCT application form to which this application was filed at the same time is incorporated by reference in its entirety for all purposes.

The present invention relates to methods of fabricating semiconductor devices. Specifically, embodiments of the present invention relate to methods of depositing carbon films in semiconductor processing.

In integrated circuit (IC) manufacturing, deposition and etching techniques are used to form patterns of materials, such as to form metal lines embedded in dielectric layers. Some patterning schemes require conformal deposition of materials, and the deposited layer must follow the contours of protrusions and/or recessed features on the surface of the substrate. ALD is often the preferred method of forming conformal films on a substrate because atomic layer deposition (ALD) relies on the adsorption of one or more reactants to the surface of the substrate, and subsequent chemical conversion of the adsorbed layer to the target material. . Since ALD uses reactions that occur on the surface of the substrate and are typically limited by the amount of adsorbed reactant, this method can provide thin conformal layers with good step coverage.

The present background description provided herein is generally intended to provide the context of the present disclosure. The achievements of the inventors currently named to the extent described in this background section, as well as aspects of technology that may not otherwise be certified as prior art at the time of filing, are not explicitly or implicitly admitted as prior art to the present disclosure.

Methods of depositing carbon layers by ALD have not been developed before. Thus, the deposition of carbon layers with a high level of control over the deposited thickness and excellent step coverage presents a difficult problem. Methods and apparatus are provided herein for depositing carbon layers in a surface-controlled manner. Conformal carbon films with good step coverage can be deposited by the methods provided and including gapfilling (e.g., when gapfilling 3D NAND structures), and self-aligning double patterning (self It can be used for various applications during spacer formation in aligned double patterning (SADP).

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 comprising the steps of: (a) introducing an aluminum-containing reactant into the processing chamber, wherein the aluminum-containing reactant is at least one Introducing an aluminum-containing reactant, which has an aluminum-carbon bond of (eg, the reactant is an alkyl-substituted aluminum, such as trialkylaluminum), into the processing chamber; (b) introducing a carbon-containing reactant into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and the carbon-containing reactant is different from the aluminum-containing reactant (e.g. For example, the carbon-containing reactant is carbon tetrahalide), introducing the carbon-containing reactant into the processing chamber; (c) at least one of an aluminum-containing reactant and a carbon-containing reactant under conditions in which 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. Adsorbing to the surface of the semiconductor substrate; And (d) at least one of an aluminum-containing reactant and a carbon-containing reactant to form an adsorption-limited layer on the surface of the semiconductor substrate, and then to form a carbon layer on the surface of the semiconductor substrate. And reacting the material and the carbon-containing reactant. Steps (a) to (d) may be repeated as many times as necessary to deposit a carbon layer having a predetermined thickness.

Suitable aluminum-containing reactants include trialkylaluminiums. In one example, the aluminum-containing reactant is trimethylaluminum. Examples of suitable carbon-containing reactants having a carbon-halide bond include CX ₄ , CHX ₃ , CH ₂ X ₂ , and CH ₃ X, where 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.

In some embodiments, the aluminum-containing reactant is trialkylaluminum, and the carbon-containing reactant is one or more of CX ₄ , CHX ₃ , CH ₂ X ₂ , and CH ₃ X, where 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 trialkylaluminum (eg, trimethylaluminum or triethylaluminum), and the carbon-containing reactant is CF ₄ , CCl ₄ , or CBr ₄ .

The reaction between the aluminum-containing reactant and the carbon-containing reactant results in the formation of aluminum-containing by-products that can be removed after the reaction is complete. By-products typically contain aluminum-halogen bonds. For example, if the carbon-containing reactant contains a carbon-fluorine bond, the by-product will include aluminum fluoride.

The introduction of reactants into the processing chamber is sequential, and the processing chamber is purged and/or evacuated after introduction of the first reactant and before introduction of the second reactant. The reactants can be introduced in any order. In one embodiment, an aluminum-containing reactant with aluminum-carbon bonds is first introduced into the processing chamber and forms an adsorption-limited layer on the surface of the substrate. The non-adsorbed aluminum-containing reactant is then removed from the processing chamber (e.g., by purge and/or evacuation), and the carbon-containing reactant is then introduced into the processing chamber and aluminum-containing reactant to form a carbon layer. It reacts with the adsorbed layer of the containing reactant. Next, the aluminum-containing by-products can be removed, and the process may be repeated as many times as necessary to deposit a carbon layer of a predetermined thickness.

In another embodiment, the process begins by first introducing a carbon-containing reactant into a processing chamber and forming an adsorption-limited layer of the carbon-containing reactant on the substrate. Unadsorbed carbon-containing reactants are removed from the processing chamber by purge and/or evacuation. Next, the aluminum-containing reactant is 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 an aluminum-containing reactant layer and a carbon-containing reactant layer formed thereon. In one embodiment, the carbon deposition method comprises the steps of adsorbing both an aluminum-containing reactant and a carbon-containing reactant on the surface of the substrate, and helium (He), argon (Ar), hydrogen (H ₂ ) and nitrogen ( And activating a reaction between adsorbed reactants on the substrate by exposing the substrate to a plasma formed of a process gas comprising a gas selected from the group consisting of N ₂ ).

In one exemplary embodiment, the plasma-activated method of forming a carbon layer on the surface of a semiconductor substrate in a processing chamber comprises: (a) introducing an aluminum-containing reactant into the processing chamber and an aluminum-containing reaction on the surface of the semiconductor substrate. Forming a layer of material, wherein the aluminum-containing reactant has at least one aluminum-carbon bond, introducing an aluminum-containing reactant into a processing chamber and forming a layer; (b) removing the aluminum-containing reactant from the processing chamber after step (a); (c) introducing a carbon-containing reactant into a processing chamber and forming a layer of a carbon-containing reactant on the surface of the semiconductor substrate, wherein the carbon-containing reactant has at least one carbon-halogen bond, and Introducing a carbon-containing reactant into a processing chamber and forming a layer, wherein the carbon-containing reactant is different from the aluminum-containing reactant; (d) removing the carbon-containing reactant from the processing chamber after step (c); And (e) a semiconductor substrate having an aluminum-containing reactant layer and a carbon-containing reactant layer to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate. And contacting the plasma with the plasma. Steps (a) to (d) can be repeated as many times as necessary to deposit a carbon layer of a desired thickness. In one example, the aluminum-containing reactant is trialkylaluminum, the carbon-containing reactant is CF ₄ , and the reaction between trialkylaluminum and CF ₄ is helium (He), argon (Ar), hydrogen (H ₂ ) And a plasma formed of a process gas including a gas selected from the group consisting of nitrogen (N ₂ ) and a semiconductor substrate.

In some embodiments, the surface of the semiconductor substrate on which the carbon layer is formed has patterned 3D features. In some implementations, the carbon layer is deposited in a gapfill operation. For example, a layer of carbon may be deposited in a gapfill operation of a partially fabricated 3D NAND structure.

In some implementations the carbon layer is conformally deposited over a semiconductor substrate having a plurality of protruding features. In one embodiment, a method includes completely removing the carbon layer from the horizontal surfaces of the protruding features without completely removing the carbon layer from the sidewalls of the protruding features; And then removing the protruding features without completely removing the carbon layer overlying the sidewalls of the protruding features, thereby forming carbon spacers on the semiconductor substrate.

In some embodiments, provided methods include applying a photoresist to a substrate; Exposing the photoresist to light; Patterning the photoresist and transferring the pattern to the substrate; And selectively removing the photoresist from the substrate.

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

In yet another aspect, a system for processing a semiconductor substrate is provided. The system includes a processing chamber, comprising: a processing chamber having a substrate holder and one or more inlets for introduction of reactants into the processing chamber; And a system controller including program instructions for performing any of the methods described herein. In one embodiment, the program instructions are (i) program instructions for causing the introduction of an aluminum-containing reactant into the processing chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond. Program instructions to trigger the introduction of; (ii) Program instructions for triggering the introduction of a carbon-containing reactant into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and the carbon-containing reactant has an aluminum-containing reactant and Program instructions to cause the introduction of a different, carbon-containing reactant into the processing chamber; (iii) an aluminum-containing reactant and a carbon-containing reaction to the surface of the semiconductor substrate under conditions in which 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. Program instructions for causing adsorption of at least one of the substances; And (iv) at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limited layer on the surface of the semiconductor substrate, and then forms a carbon layer on the surface of the semiconductor substrate. Contains program instructions to trigger a reaction between a substance and a carbon-containing reactant.

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

1 is a process flow diagram for a method of depositing carbon, according to an embodiment provided herein.
2A is a process flow diagram for a method of depositing carbon, according to an embodiment provided herein.
2B is a process flow diagram for a method of depositing carbon, according to another embodiment provided herein.
3A-3F show schematic cross-sectional views of a semiconductor substrate undergoing processing, in accordance with an embodiment provided herein.
4 is a process flow diagram for a method of forming carbon spacers, according to an embodiment provided herein.
5 and 6 show schematic cross-sectional views of a semiconductor substrate undergoing processing, according to an embodiment provided herein.
7 is a schematic representation of an apparatus suitable for depositing carbon films, according to an embodiment provided herein.
8 shows a schematic diagram of a multi-station processing system, according to an embodiment provided herein.
9 shows a schematic diagram of a multi-station processing system, according to an embodiment provided herein.

Methods of depositing carbon films using ALD are provided. These methods may be used to deposit conformal carbon films on semiconductor substrates with 3D structures on a surface, such as substrates with one or more recessed features or one or more protrusions. I can. In some embodiments, the methods include between an aluminum-containing reactant having an Al-C bond (eg, trialkylaluminum) and a carbon-containing reactant having a carbon-halogen bond (eg, CF ₄ ). It involves a reaction.

The term “ALD” as used herein generally refers to deposition methods that rely on reactions (adsorption-limited reactive layer) limited by the amount of reactant adsorbed on the surface of the substrate. The adsorption-limited layers of reactants may comprise an adsorption-limited layer of an aluminum-containing reactant, an adsorption-limited layer of a carbon-containing reactant, or an adsorption-limited layer of both reactants. In some embodiments ALD methods involve sequential introduction of reactants into the processing chamber such that the reactants are not allowed to mix throughout the processing chamber.

In some embodiments, carbon films are deposited in gapfill applications. For example, in one implementation, carbon films may be deposited during gapfill during 3D NAND fabrication. In some implementations the carbon films are used as spacers in self aligned double patterning (SADP). However, the provided methods are not limited to the deposition of carbon films on surfaces with recessed features, but can also be used to deposit blanket carbon films on planar surfaces. Methods rely on surface-controlled reactions and can be used to deposit films with a high degree of control over the film thickness. Films can be deposited in a wide variety of devices that allow sequential introduction of reactants into the process chamber. For example, the carbon film can be deposited in a vapor deposition system available Striker ^® from Lam Research Corporation.

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

The term “semiconductor substrate” as used herein refers to a substrate at any stage of semiconductor device manufacturing that contains semiconductor material anywhere within the structure. It is understood that the semiconductor material of the semiconductor substrate need not be exposed. Semiconductor wafers having a plurality of layers of different materials (eg, dielectrics) covering the semiconductor material are examples of semiconductor substrates. The detailed description below assumes disclosed implementations implemented on a wafer. However, the disclosed implementations are not so limited. The workpiece may be of various shapes, sizes, and materials. In addition to semiconductor wafers, other workpieces that may take advantage of the disclosed implementations include various articles such as printed circuit boards and the like.

The process for depositing carbon films is illustrated by the process flow diagram shown in FIG. 1. In operation 101, an aluminum-containing reactant is introduced into the processing chamber housing the 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 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 as a gas. The reactant may be introduced in a mixture with a carrier gas, and the carrier gas is typically an inert gas such as N ₂ , 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 a Vapbox DLI vaporizer available from Kemstream.

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

The aluminum-containing reactant and carbon-containing reactant are typically introduced sequentially into the processing chamber without mixing in most of the processing chamber. The order of introduction may vary according to embodiments. 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, aluminum-containing reactant, carbon-containing reactant, or both) forms an adsorption-limited layer on the substrate. In some embodiments, the first-introduced reactant forms an adsorption-limited layer on the substrate, and the second-introduced reactant is in contact with the second-introduced reactant and the adsorption-limited layer. Then react with the adsorption-limited layer of the first reactant. In other embodiments, the first-introduced reactant forms an adsorption-limited layer, the second-introduced reactant also forms an adsorption-limited layer, and the two reactants are then, for example, thermally activated. Or after plasma activation, it reacts on the surface of the substrate. In some embodiments, the reaction is activated by contacting the substrate with a plasma formed of a gas such as helium (He), argon (Ar), hydrogen (H ₂ ) and nitrogen (N ₂ ), or any mixture thereof. Activation of the reaction using plasma may also be used to allow the formation of carbon at relatively low temperatures. In some embodiments carbon films are 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 processing chamber is purged after introduction of the first reactant and prior to introduction of the second reactant to remove unadsorbed first-introduced reactant from the processing chamber. /Or exhausted.

In operation 105, the aluminum-containing reactant reacts with the carbon-containing reactant to form a carbon layer on the surface of the substrate, and the amount of carbon formed is determined by the amount of the reactant (e.g., the aluminum-containing reactant and/or Is limited by the adsorption-limited layer of the carbon-containing reactant. In the reaction, the aluminum-carbon bonds of the aluminum-containing reactant and the carbon-halogen bonds of the carbon-containing reactant are broken to form carbon (which may include CH bonds) and by-products containing aluminum-halogen bonds broken). For example, when the halogen of the carbon-containing reactant is fluorine, an aluminum-fluorine bond containing by-product will be formed. In some embodiments, the reaction occurs spontaneously after the reactants come into contact. In other embodiments, the reaction is activated (eg, thermally) after the reactants are brought into contact.

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

One cycle of deposition, including operations 101-105, deposits an average of 0.5 to 3 Å of carbon film in some embodiments. The cycles can be repeated as many times as necessary to deposit a carbon film of the desired thickness. For example, carbon films having thicknesses of 5 to 1,000 Å are deposited in some embodiments.

One embodiment of a carbon deposition method is illustrated by the process flow diagram shown in FIG. 2A. The process begins at 201 by adsorbing an aluminum-containing reactant on a semiconductor substrate. An aluminum-containing precursor, such as trialkylaluminum, may flow into the process chamber along with the carrier gas and may be allowed to adsorb to the surface of the substrate. The process conditions for this step are selected so that an adsorption-limited layer of the aluminum-containing reactant is formed. Next, in operation 203, the unadsorbed aluminum-containing reactant is removed from the processing chamber by purging and/or evacuating the processing chamber. For example, the processing chamber may be purged using an inert gas such as N ₂ , He, Ar, Ne, or the like. After this step, there is no aluminum-containing precursor in most of the processing chamber and all subsequent reactions are limited by the amount of aluminum-containing reactant adsorbed on the substrate. Next, in operation 205, the carbon-containing reactant is introduced into the processing chamber and reacts 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 carbon-containing reactant is introduced.

Next, in operation 207, the aluminum-containing by-product is removed from the processing chamber. This step is optional because in some embodiments the by-product is removed simultaneously with carbon formation. When the by-product is not removed simultaneously with the carbon formation reaction, it can be removed by a separate step, for example heating.

Next, in operation 209, the deposition of carbon (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, at least 5 or at least 10 cycles are performed, each of which includes operations 201 through 205. During processing the temperature and pressure are controlled to allow the formation of adsorption-limited layers of one or two reactants on the substrate. In some embodiments the temperature is maintained below about 400° C. during the entire deposition sequence, and the pressure is maintained at subatmospheric levels. The deposition of carbon films using the described reactants can be carried out in the absence of plasma. In some embodiments, plasma treatment may 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 surface of the substrate.

2B provides a process flow diagram for a method of forming a carbon layer using a plasma-activated reaction. Referring to FIG. 2B, the process begins at 211 by forming a layer of aluminum-containing reactant on the substrate. For example, an adsorption-limited layer of aluminum-containing reactants can be formed on the substrate. Next, in operation 213, the processing chamber is purged and/or evacuated to remove the aluminum-containing reactant from the processing chamber. For example, an inert gas can be used as a purge gas for removing 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 may be introduced into the processing chamber and may be allowed to form an adsorption restricted layer on the substrate. In operation 217, the processing chamber is purged and/or evacuated to remove the carbon-containing material from the processing chamber. After this operation, there are a layer of an aluminum-containing material and a layer of a carbon-containing material on the surface of the substrate. Next, in operation 219, the substrate is treated with plasma to activate the 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 formed of helium (He), argon (Ar), hydrogen (H ₂ ), nitrogen (N ₂ ), or any mixture of these gases. The reaction by-products may be removed simultaneously with the plasma treatment or in a subsequent step. After plasma treatment, the processing chamber may be purged and/or evacuated, and the processing sequence of steps 211 to 219 may be repeated as many times as necessary until a carbon layer having a predetermined thickness is deposited in operation 221. In an exemplary embodiment, the aluminum-containing reactant is trialkylaluminum (eg, trimethylaluminum or triethylaluminum) and the carbon-containing reactant is CF ₄ .

Carbon films deposited by the methods provided herein can be used in various applications in semiconductor device manufacturing. These are particularly advantageous if conformal deposition of films on substrates with 3D features (eg, protruding features or recessed features) is desired. In some embodiments carbon films are used as spacers in patterning applications. An example of carbon spacer formation is provided in FIGS. 3A-3F, in which schematic cross-sectional views of a semiconductor substrate are illustrated during different stages of processing. 4 provides an exemplary process flow diagram for a semiconductor processing method involving the formation of carbon mandrels.

Referring to Figure 4, the illustrated process begins at 401 by providing a substrate with a plurality of protruding features, also referred to as mandrels. An exemplary substrate is shown in FIG. 3A, showing two mandrels 301 residing on an etch stop layer (ESL) 303. The distance d1 between neighboring mandrels is about 10-100 nm in some embodiments. Relatively larger distances of about 40-100 nm are used in some embodiments. In other applications, the distance between the closest mandrels is about 10 to 30 nm. The distance d2 between the closest mandrels, also referred to as the pitch, is in some embodiments about 30-130 nm. 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 mandrels is typically about 20 to 200 nm, such as about 50 to 100 nm.

The materials of the mandrel and the materials of the ESL are selected to allow for the subsequent selective etching of the mandrel material in the presence of exposed carbon, and the selective etching of the ESL material in the presence of exposed carbon. Thus, the ratio of the etch rate of the ESL material to the etch rate of carbon is greater than 1, more preferably greater than about 1.5, such as greater than about 2 for the first etch chemistry. 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 etching (e.g., fluorocarbon). It is a plasma formed of a gas containing). In some embodiments, the ESL material is a metal oxide or metal nitride, and the first etch chemistry is a halogen-based plasma etch (eg, a plasma formed from a process gas comprising halogen). Similarly, the ratio of the etch rate of the mandrel material to the etch rate of carbon is greater than 1, more preferably greater than about 1.5, such as greater than about 2 for the second etch chemistry. In some embodiments, the mandrel material is a silicon-containing material (e.g., a silicon-containing compound), and the first etch chemistry is a fluorine-based plasma etching (e.g., with a gas comprising fluorocarbon). Formed plasma). In some embodiments, the mandrel material is a metal oxide or metal nitride, and the first etch chemistry is a halogen-based plasma etch (eg, a plasma formed with a process gas comprising 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 a silicon-containing compound (e.g., SiO ₂ , SiN, or SiC), amorphous silicon (doped or undoped) or a metal oxide (TaO, TiO, WO, ZrO, HfO). . In some embodiments, the outer material of the mandrel may be different from the mandrel core. For example, in some embodiments the mandrel is made of amorphous silicon and covered with silicon oxide (eg, with a spontaneously formed thermal oxide layer). The ESL layer and mandrel may be formed by one or more of physical vapor deposition (PVD), chemical vapor deposition (CVD), ALD (without using plasma or by PEALD), or plasma enhanced chemical vapor deposition (PECVD), and , The pattern of mandrels can be defined using photolithographic techniques. 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; And (iii) a metal oxide ESL and a silicon oxide covered silicon mandrel.

Referring back to the substrate shown in FIG. 3A, the ESL layer 303 is overlying in contact with the target layer 305. The target layer 305 is a layer to be patterned. The target layer 305 may be a semiconductor, dielectric 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 hardmask layer and includes a metal nitride, such as titanium nitride. The target layer 305 may be deposited by ALD (without using plasma or by PEALD), CVD, or other suitable deposition technique.

Target layer 305 is in contact with and overlies layer 307, which in some embodiments is a BEOL layer, comprising a plurality of metal lines embedded within a layer of dielectric material.

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

After the carbon layer has been conformally deposited, the process continues to 405 by completely removing the carbon layer from the horizontal surfaces without completely removing the carbon layer from the sidewalls of the protruding features. This etching can be performed using oxygen-based plasma etching (eg, using a plasma formed from a gas comprising oxygen). In other embodiments, a hydrogen-based etching (eg, using a plasma formed with a process gas comprising hydrogen) may be used. If the mandrels have silicon-containing compounds or metal oxides as the outer layer, then hydrogen-based or oxygen-based etching can be used. The etch chemistry utilized in this step should preferably be selective for both ESL materials and for the material of the outer layer of the mandrel, i.e. the etch rate of carbon for this etch chemistry is greater than the etch rate of the outer mandrel material. Should be greater than the etch rate of the ESL material. The removal of the carbon layer from horizontal surfaces is illustrated by FIG. 3C. The carbon layer 309 is not completely etched from the locations adhering to the sidewalls of the mandrels 301, but from horizontal surfaces over the ESL 303 and over the mandrels 301. This etch exposes layer 303 anywhere except locations near the sidewalls of mandrels 301. Also, this etch exposes the upper portions of the mandrels. The resulting structure is shown in Fig. 3C. Preferably at least 50%, such as at least 80% or at least 90% of the initial height of the carbon layer in the sidewall is preserved after this etching. In one example carbon is selectively etched from the silicon oxide covered mandrel by hydrogen-based etching (eg, H ₂ plasma etching) such that the outer material of the mandrel (SiO ₂ ) is exposed. Hydrogen-based etching is selective for SiO ₂ . In another example carbon is a metal oxide by hydrogen-based etching (e.g., H ₂ plasma etching) or oxygen-based etching (e.g., O ₂ plasma etching) so that the mandrel material (metal oxide) is exposed. It is selectively etched from the mandrel (eg titanium oxide). These etch chemistries are selective for oxides of metals that do not form volatile hydrides, such as titanium oxide.

A next step 407 entails completely removing the protruding features without completely removing the carbon layer overlying the sidewalls of the protruding features, thereby forming carbon spacers. As shown in FIG. 3D, mandrels 301 are removed from the substrate leaving exposed carbon spacers 301 and exposed layer ESL 303. Removal of mandrels is accomplished by exposing the substrate to an etching chemical that selectively etchs the mandrel material. Therefore, the ratio of the etching rate of the mandrel material to the etching rate of carbon in this step is greater than 1, and more preferably greater than 1.5. Also, the etch chemistry used in this step must, in some embodiments, selectively etch the mandrel material relative to the ESL material. Various etching methods can be used, and the particular choice of chemistry depends on the material of the mandrel and the material of the ESL layer. If the mandrel is made of amorphous silicon covered with silicon oxide, a fluorine-based chemical (eg, NF ₃ ) may be used to remove the silicon mandrels 301 along with the SiO ₂ layer covering it. This chemical is selective for carbon.

When the mandrel is a metal oxide (e.g., titanium oxide, tungsten oxide, zirconium oxide, hafnium oxide, tantalum oxide), the substrate is chlorine-based etching chemicals (e.g. For example, the plasma may be treated with BCl ₃ /Cl ₂ ). This chemical can be used in the presence of an ESL containing silicon-containing compounds (eg SiO ₂ , SiN, SiC).

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. The resulting structure is shown in Fig. 3E. The etching chemistry used in this step selectively etch 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 carbon is greater than 1, and more preferably greater than 1.5. The specific type of chemical used in this step will depend on the type of ESL material. When silicon-containing compounds (eg, 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 comprising fluorocarbon. For example, the ESL film may be etched by a plasma formed from a process gas containing at least one 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), a chlorine-based etching chemistry (e.g., BCl ₃ /Cl _{2 in} plasma) is used to selectively in the presence of carbon. Can be etched.

In the next step, The target layer 305 is etched at all locations not protected by the ESL film 303 to expose the lower layer 307. Carbon spacers 309 are also removed in this etch step to provide the patterned structure shown in FIG. 3F. In some embodiments, the etch 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 may be used to pattern the target layer 305 and remove the carbon spacers 309 respectively. Depending on the chemistry of the target layer, multiple etch chemistries can be used. In one embodiment the target layer 305 is a metal nitride layer (eg, TiN) layer. In this embodiment, the metal nitride layer may be etched by exposing the substrate to a plasma formed with a process gas comprising Cl ₂ and hydrocarbon (e.g., CH ₄ ), or by oxygen-based plasma etching chemicals or hydrogen- Carbon spacer removal is followed by using a plasma-based etch chemistry.

The carbon deposition methods provided in some embodiments are used in gapfill applications. Upon gapfilling, a substrate including one or more recessed features is provided to the processing chamber, and carbon is deposited using methods provided to cover both the bottom portions and sidewalls of the recessed features. Deposition cycles are performed as many times as necessary to fill the recessed feature with carbon. Due to the very conformal nature of the deposition, seamless gap fill may be achieved in some embodiments. The provided methods are particularly useful for depositing carbon on high aspect ratio features. In some embodiments the aspect ratio of the recessed features is at least 5:1, such as at least 10:1.

In one example, carbon is used for gap filling in 3D NAND manufacturing processes. In one embodiment, a partially fabricated 3D NAND structure with at least one recessed feature is provided to the process chamber and carbon is at least one recessed to fill the recessed feature using the methods provided herein. It is deposited into the recessed feature. An example of this application is provided in FIGS. 5 and 6, illustrating schematic cross-sectional views of a partially fabricated 3D NAND structure.

5 shows an exemplary substrate 1100 having a plurality of alternating layers 1111 and 1140 deposited in a stepped pattern over the substrate 1100. In some embodiments layers 1111 are dielectric layers (eg, silicon oxide) and layers 1140 are conductive layers (eg, tungsten layers). Alternatively, layers 1111 and 1140 may be different types of dielectrics, such as silicon oxide layers 1111 and silicon nitride layers 1140. A hardmask layer 1110 is placed on top layer 1140, and an encapsulation layer 1139 laterally encapsulates a stepped pattern of alternating layers 1111 and 1140. A plurality of vias 1137 are etched in the dielectric 1122 (eg, in silicon oxide), for example the material of the layer 1140 is exposed at the lower ends 1139 of the vias 1137. Vias 1137 have different depths since material 1140 is shown in FIG. 5. In the next step, carbon is deposited into vias 1137 in a gapfill operation using the deposition methods provided herein. The resulting structure is shown in FIG. 6, the carbon layer 1173 fills all vias (channels), and the carbon filled vias contact the material 1140 at the lower ends. Carbon can be used as the sacrificial material of the channels, and during subsequent fabrication, the carbon can be removed from the channels using, for example, oxygen-based plasma etching or hydrogen-based plasma etching and vias will be filled with a conductive material. I can.

Device

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

For example, in some embodiments, the apparatus includes (i) program instructions for causing the introduction of an aluminum-containing reactant into the processing chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond. -Program instructions to trigger the introduction of the containing reactant; (ii) Program instructions for triggering the introduction of a carbon-containing reactant into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and the carbon-containing reactant has an aluminum-containing reactant and Program instructions to cause the introduction of a different, carbon-containing reactant into the processing chamber; (iii) an aluminum-containing reactant and a carbon-containing reaction to the surface of the semiconductor substrate under conditions in which 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. Program instructions for causing adsorption of at least one of the substances; And (iv) at least one of the aluminum-containing reactant and the carbon-containing reactant forms an adsorption-limited layer on the surface of the semiconductor substrate, and then forms a carbon layer on the surface of the semiconductor substrate. And a controller, including program instructions for causing a reaction between the substance and the carbon-containing reactant.

An example of a deposition apparatus suitable for depositing carbon using the methods provided is shown in FIG. 7. 7 schematically depicts one embodiment of a process station 700, which may be used to deposit material using atomic layer deposition (ALD) and/or chemical vapor deposition (CVD), each of which may be plasma enhanced. . For the sake of brevity, the process station 700 is shown as a standalone process station with a process chamber body 702 to maintain a low pressure atmosphere. 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 discussed in detail below, may be adjusted programmatically by one or more computer controllers.

Process station 700 is in fluid communication with reactant delivery system 701 to deliver process gases to dispensing 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 may control the introduction of process gases to mixing vessel 704. Similarly, showerhead inlet valve 705 may control the introduction of process gases to showerhead 706.

Some reactants, such as trimethylaluminum, may also be stored in liquid form prior to vaporization at the process station and subsequent delivery to the process station. For example, the embodiment of FIG. 7 includes a vaporization point 703 for vaporizing a liquid reactant to be fed to the mixing vessel 704. In some embodiments, vaporization point 703 may be a heated vaporizer. The reactant vapors produced from these vaporizers may be condensed in the downstream delivery pipe. Exposure of incompatible gases to the condensed reactant may produce small particles. These small particles can clog pipes, interfere with valve operation, contaminate substrates, and so on. Some approaches to addressing these problems involve sweeping and/or evacuating the delivery pipe to remove residual reactants. However, sweeping the transfer pipe may increase the process station cycle time, deteriorating the process station throughput. Thus, in some embodiments, the transfer pipe downstream of the vaporization point 703 may be heat traced. In some examples, mixing vessel 704 may also be heat traced. In one non-limiting example, the pipe downstream of vaporization point 703 has a rising temperature profile extending from approximately 100° C. to approximately 150° C. in mixing vessel 704.

In some embodiments, the reactant liquid may be vaporized in a liquid injector. For example, pulses of liquid reactant may be injected into the carrier gas stream upstream of the mixing vessel. In one scenario, the liquid injector may vaporize the reactants by flashing the liquid from a higher pressure to a lower pressure. In another scenario, the liquid injector may atomize the liquid into dispersed microdroplets that later vaporize in a heated delivery pipe. It will be appreciated that smaller droplets may vaporize faster than larger droplets, reducing the delay between liquid injection and complete vaporization. Faster vaporization may reduce the pipe length downstream from vaporization point 703. In one scenario, the liquid injector may be mounted directly to the mixing vessel 704. In another scenario, the liquid injector may be mounted directly to the showerhead 706.

In some embodiments, a liquid flow controller (LFC) upstream of the vaporization point 703 may be provided to control the bulk flow of liquid for vaporization and delivery to the process station 700. For example, the LFC may include a thermal mass flow meter (MFM) located downstream of the LFC. The LFC's plunger valve may then be adjusted in response to feedback control signals provided by a proportional-integral-derivative (PID) controller in electrical communication with the MFM. However, it may take more than 1 second to stabilize the liquid flow using the feedback control. This may extend the time for dosing the liquid reactant. Thus, in some embodiments, the LFC may be dynamically switched between the feedback control mode and the direct control mode. In some embodiments, the LFC may be dynamically switched from the feedback control mode to the direct control mode by disabling the sense tube of the LFC and PID controller.

The showerhead 706 distributes process gases towards the substrate 712. In the embodiment shown in FIG. 7, the substrate 712 is shown positioned below the showerhead 706 and overlying the pedestal 708. It will be appreciated that the showerhead 706 may have any suitable shape and may have any suitable number and arrangement of ports for distributing process gases to the substrate 712.

In some embodiments, a microvolume 707 is located under the showerhead 706. Performing the ALD and/or CVD process in a microvolume rather than the entire volume of the process station may reduce reactant exposure and sweeping times and change process conditions (e.g., pressure, temperature, etc.) May reduce the times for, limit the exposure of process station robotics to process gases, etc. Exemplary microvolume sizes include, but are not limited to, volumes of 0.1 L to 2 L. This microvolume also affects productivity throughput. While the deposition rate per cycle drops, the cycle time also decreases simultaneously. In certain cases, the latter effect is dramatic enough to improve the overall throughput of the module for a predetermined target thickness of the film.

In some embodiments, pedestal 708 may be raised or lowered to expose substrate 712 to microvolume 707 and/or to vary the volume of microvolume 707. For example, in the substrate transfer phase, the pedestal 708 may be lowered to cause the substrate 712 to be loaded onto the pedestal 708. During the deposition process phase, the pedestal 708 may be raised to position the substrate 712 within the microvolume 707. In some embodiments, the microvolume 707 may completely encapsulate a portion of the pedestal 708 as well as the substrate 712 to create a high flow impedance region during the deposition process.

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

Although the exemplary microvolume fluctuations 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 to vary the volume of microvolumes therebetween. It will be understood that there is. Further, it will be appreciated that the vertical position of pedestal 708 and/or showerhead 706 may be varied by any suitable mechanism within the scope of this disclosure. In some embodiments, pedestal 708 may include an axis of rotation to rotate the orientation of substrate 712. It will be appreciated that in some embodiments, one or more of these exemplary adjustments may be performed programmatically by one or more suitable computer controllers.

Referring back to the embodiment shown in FIG. 7, the showerhead 706 and the pedestal 708 electrically communicate with the radio frequency (RF) power supply 714 and the matching network 716 to supply power to the plasma. do. In other embodiments devices that do not use a plasma generator are used to deposit carbon using the methods provided. 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 supply 714 and matching network 716 may be operated at any suitable power to form a plasma having a desired composition of radical species. Examples of suitable power have been included above. Similarly, the RF power supply 714 may provide RF power of any suitable frequency. In some embodiments, the RF power supply 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 of 50 kHz to 700 kHz. Exemplary high frequency RF frequencies may include, but are not limited to, frequencies of 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 for continuously powered plasmas.

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 of a voltage sensor, a current sensor (eg, VI probes). In another scenario, plasma density and/or process gas concentration may be measured by one or more optical emission spectroscopy (OES) sensors. In some embodiments, one or more plasma parameters may be adjusted programmatically based on measurements from such in-situ plasma monitors. For example, an OES sensor may be used in a feedback loop for programmatic 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 through input/output control (IOC) sequencing instructions. In one example, instructions for setting plasma conditions for a plasma process phase may be included in a corresponding plasma activation recipe phase of the deposition process recipe. In some cases, the process recipe phases may be arranged sequentially such that all instructions for the deposition process phase are executed concurrently with the process phase. In some embodiments, instructions for setting one or more plasma parameters may be included in a recipe phase preceding the plasma process phase. For example, the first recipe phase includes instructions for setting the flow rate of the inert gas and/or reactant gas, instructions for setting the plasma generator as a power set point, and a time delay instruction for the first recipe phase. Can also include. The second, subsequent recipe phase may include instructions to enable the plasma generator and time delay instructions for the second recipe phase. The third recipe phase may include instructions for disabling the plasma generator, and time delay instructions for the third recipe phase. It will be appreciated that these recipe phases 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 through heater 710. Further, in some embodiments, pressure control for the deposition process station 700 may be provided by the butterfly valve 718. As shown in the embodiment of Figure 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 may also be adjusted by varying the flow rate of one or more gases introduced into the process station 700.

8 shows a schematic diagram of an embodiment of a multi-station processing tool 800 with an inbound loadlock 802 and an outbound loadlock 804, among the inbound loadlock 802 and outbound loadlock 804 One or all may comprise a remote plasma source. Such a tool may be used to process substrates using the methods provided herein. At atmospheric pressure, the robot 806 is configured to move wafers loaded from the cassette through the pod 808 to the inbound loadlock 802 through the standby port 810. The wafer is placed by the robot 806 on the pedestal 812 in the inbound loadlock 802, the standby port 810 is closed, and the loadlock is pumped down. If the inbound loadlock 802 includes a remote plasma source, the wafer may be exposed to remote plasma processing within the loadlock before being introduced into the processing chamber 814. In addition, the wafer may also be heated in the inbound loadlock 802 to remove moisture and adsorbed gases, for example. Next, the chamber transfer port 816 to the processing chamber 814 is opened, and another robot (not shown) places the wafer into the reactor on the pedestal of the first station shown in the reactor for processing. Although the embodiment shown in FIG. 8 includes loadlocks, it will be appreciated that in some embodiments, direct entry of the wafer into the process station may be provided.

The illustrated processing chamber 814 includes four process stations, numbered 1 to 4 in the embodiment shown in FIG. 8. Each of the stations has a heated pedestal (shown as 818 for station 1), and gas line inlets. It will be appreciated that in some embodiments, each of the process stations may have a different purpose or multiple purposes. Although the illustrated processing chamber 814 includes four stations, it will be appreciated that the processing chamber according to the present disclosure may have any suitable number of stations. For example, in some embodiments, the processing chamber may have 5 or more stations, while in other embodiments the processing chamber may have 3 or fewer stations.

FIG. 8 also shows an embodiment of a wafer handling system 890 for transferring wafers within the processing chamber 814. In some embodiments, the wafer handling system 890 may transfer wafers between various process stations and/or between a process station and a load lock. It will be appreciated that any suitable wafer handling system may be employed. Non-limiting examples include wafer carousels and wafer handling robots. 8 also shows an embodiment of a system controller 850 employed to control the process conditions and hardware states of the process 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 input/output connections and/or digital input/output connections, stepper motor control boards, and the like.

In some embodiments, system controller 850 controls all the activities of process tool 800. System controller 850 executes system control software 858 stored in mass storage device 854 and loaded into memory device 856 and executed on processor 852. System control software 858 includes timing, mixture of gases, chamber and/or station pressure, chamber and/or station temperature, purge conditions and timing, wafer temperature, RF power levels, RF frequencies, substrate, pedestal, chuck. And/or susceptor location, 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 created to control the operation of process tool components required to execute various process tool processes according to 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) sequencing instructions to control the various parameters described above. For example, each phase of an ALD process may include one or more instructions for execution by system controller 850. Instructions for setting process conditions for an ALD process phase may be included in the corresponding ALD recipe phase. In some embodiments, the ALD recipe phases may be arranged sequentially, such that all instructions for an ALD process phase are executed concurrently with the process phase.

Other computer software and/or programs stored in the mass storage device 854 and/or memory device 856 associated with the system controller 850 may be employed in some embodiments. Examples of programs or sections of programs for this purpose include a substrate positioning program, a process gas control program, a pressure control program, a heater control program, and a plasma control program.

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

The process gas control program may include code for controlling gas composition and flow rates and optionally code for flowing gas into one or more process stations prior to deposition to stabilize pressure in the process station. The process gas control program may include code for controlling the gas composition and flow rates within any disclosed ranges. The pressure control program may include code for controlling the pressure in the process station, gas flow into the process station, etc., for example by regulating the throttle valve of the exhaust system of the process station. The pressure control program may include code to maintain the pressure of the process station within any 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 may control the delivery of a heat transfer gas (such as helium) to the substrate. The heater control program may include instructions for maintaining the temperature of the substrate within any disclosed ranges.

The plasma control program may, for example, include code for setting RF power levels and frequencies applied to the process electrodes of one or more process stations using any of the RF power levels disclosed herein. The plasma control program may also include code for controlling the duration of each plasma exposure.

In some embodiments, there may be a user interface associated with the system controller 850. The user interface may include user input devices such as a display screen, graphical software displays of apparatus and/or process conditions, pointing devices, keyboards, touch screens, microphones, and the like.

In some embodiments, 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 levels, frequency, and exposure time), and the like. These parameters may be provided to the user in the form of a recipe, which may be input using a user interface.

Signals for monitoring the process may be provided by analog input connections and/or digital input connections of the system controller 850 from various process tool sensors. Signals for controlling the process may be output to analog output connections and 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 (such as manometers), thermocouples, and the like. Appropriately programmed feedback and control algorithms may be used with data from these sensors to maintain process conditions.

Any suitable chamber may be used to implement the disclosed embodiments. An exemplary deposition apparatus are, but are not limited to, but include equipment or any of a variety of commercially available processing systems other commercially from California, Fremont Striker ^® family, available from Lam Research Corp. of material. Two or more stations may perform the same functions. Similarly, two or more stations may perform different functions. Each of the stations can be designed/configured to perform a specific function/method as desired.

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. The transfer module 903 provides a clean, pressurized atmosphere to minimize the risk of contamination of the substrates to be processed when moved between the various reactor modules. Two multi-station reactors 909 and 910 are mounted on the transfer module 903, each capable of performing atomic layer deposition (ALD) and/or chemical vapor deposition (CVD) according to specific embodiments. . Reactors 909 and 910 may include a plurality of stations 911, 913, 915, and 917 that may sequentially or out of sequence perform operations according to the disclosed embodiments. The stations may include a heated pedestal or substrate support, one or more gas inlets or a showerhead or dispersion plate.

In addition, one or more single station or multi-station modules 907 capable of performing plasma or chemical (non-plasma) pre-cleans or any other processes described in connection with the disclosed methods include transfer module 903. It can also be mounted on top. Module 907 may be used in various processes in some cases, eg, 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 in which wafers are stored before and after processing. An atmospheric robot (not shown) in the atmospheric transfer chamber 919 may first remove wafers from the source modules 901 to the loadlocks 921. A wafer transfer device (generally a robot arm unit) of the transfer module 903 moves wafers from the loadlocks 921 to the modules mounted on the transfer module 903 and between modules.

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

Controller 929 may control all activities of the deposition apparatus. System controller 929 provides sets of instructions for controlling timing, mixture of gases, chamber pressure, chamber temperature, wafer temperature, radio frequency (RF) power levels, wafer chuck or pedestal position, and other parameters of a particular process. Run the included system control software. Other computer programs stored in memory devices associated with controller 929 may be employed in some embodiments.

Typically there will be a user interface associated with the controller 929. The user interface may include a display screen, graphical software displays of apparatus and/or process conditions, and user input devices such as pointing devices, keyboards, touch screens, microphones, and the like.

System control logic may be configured in any suitable manner. In general, this logic can be designed or configured in hardware and/or software. Instructions for controlling the driving circuit may be hardcoded or may be provided in software. Instructions may be provided by "programming". Such programming includes any type of logic, including digital signal processors (DSPs), application-specific integrated circuits (ASICs), and logic hardcoded in other devices with specific algorithms implemented as hardware. I understand. Programming is also understood to include software or firmware instructions that may be executed on a general purpose processor. The system control software may be coded in any suitable computer readable programming language.

Computer programs for controlling germanium-containing reducing agent pulses, hydrogen flow, and tungsten-containing precursor pulses, and other processes of a process sequence are available 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. As also indicated, the program code may be hardcoded.

The controller parameters relate to process conditions such as, for example, process gas composition and flow rates, 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 may be input using a user interface. Signals for monitoring the process may be provided by analog input connections and/or digital input connections of system controller 929. Signals for controlling the process are output on the analog output connections and digital output connections of the deposition apparatus 900.

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 the chamber components necessary to perform the deposition processes (and in some cases, other processes) in accordance with the disclosed embodiments. . 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, which may be part of the examples described above. Such systems may include semiconductor processing equipment, including processing tool or tools, chamber or chambers, platform or platforms for processing, and/or specific processing components (wafer pedestal, gas flow system, etc.) . These systems may be integrated into electronics for controlling their operation prior to, during and after processing of a semiconductor wafer or substrate. Electronics may be referred to as a “controller” that may control the system or various components or sub-parts of the systems. The controller can, depending on the processing requirements and/or the type of system, the delivery of processing gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings. , Radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and motion settings, tools and other transport in some systems. It may be programmed to control any of the processes disclosed herein, including wafer transfers into and out of loadlocks connected or interfaced with tools and/or a particular system.

Generally speaking, the controller receives instructions, issues instructions, controls operation, enables cleaning operations, enables endpoint measurements, etc. Various integrated circuits, logic, memory, and/or It may be defined as an electronic device with software. Integrated circuits are chips in the form of firmware that store program instructions, digital signal processors (DSP), chips defined as application specific integrated circuits (ASICs), and/or one that executes program instructions (e.g., software). It may include the above microprocessors or microcontrollers. Program instructions may be instructions that are passed to a controller or to a system in the form of various individual settings (or program files) that specify operating parameters for executing a specific process on or on a semiconductor wafer. In some embodiments, the operating parameters are processed to achieve one or more processing steps during fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of the wafer. It may be part of a recipe prescribed by the engineers.

The controller may be coupled to, or be part of, a computer, which in some implementations may be integrated into the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or part of a fab host computer system that may enable remote access of wafer processing. The computer monitors the current progress of manufacturing operations, examines the history of past manufacturing operations, examines trends or performance metrics from a plurality of manufacturing operations, changes parameters of current processing, and performs processing steps following the current processing. You can configure, or enable remote access to the system to start a new process. In some examples, a remote computer (eg, a server) can provide process recipes to the system over a local network or a network that may include the Internet. The remote computer may include a user interface that enables programming or input of parameters and/or settings to be subsequently passed from the remote computer to the system. In some examples, the controller receives instructions in the form of data, specifying parameters for each of the process steps to be performed during one or more operations. It should be understood that these parameters may be specific to the type of tool the controller is configured to control or interface with and the type of process to be performed. Thus, as noted above, the controller may be distributed, for example, by including one or more individual controllers that are networked with each other and cooperate together for a common purpose, eg, for the processes and controls described herein. An example of a decentralized controller for this purpose is one or more integrated circuits on a chamber that communicate with one or more remotely located integrated circuits (e.g., at the platform level or as part of a remote computer) that are combined to control a process on the chamber. It can be circuits.

Without limitation, exemplary systems include plasma etch chamber or module, deposition chamber or module, spin-rinse chamber or module, metal plating chamber or module, cleaning chamber or module, bevel edge etch chamber or module, physical vapor deposition (PVD). Chamber or module, chemical vapor deposition (CVD) chamber or module, atomic layer deposition (ALD) chamber or module, atomic layer etch (ALE) chamber or module, ion implantation chamber or module, track chamber or module, and semiconductor It may include any other semiconductor processing systems that may be used or associated with the fabrication and/or fabrication of wafers.

As described above, depending on the process step or steps to be performed by the tool, the controller is used in material transfer to move containers of wafers to/from tool locations and/or load ports within a semiconductor fabrication plant. May communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, main computer, another controller or tools .

Additional implementations

The apparatus/processes described herein may be used in conjunction with lithographic patterning tools or processes for manufacturing or fabricating, for example, semiconductor devices, displays, LEDs, photovoltaic panels, and the like. Typically, but not necessarily, these devices and processes will be performed and used together in a common manufacturing facility. Lithographic patterning of the film typically involves the following steps, each of which is enabled using a number of possible tools: (1) a workpiece using a spin-on tool or a spray-on tool. That is, applying a photoresist on the substrate; (2) curing the photoresist using a hot plate or furnace or UV curing tool; (3) exposing the photoresist to visible or UV or x-ray light using a tool such as a wafer stepper; (4) developing the resist to pattern the resist by selectively removing the resist using a tool such as a wet bench; (5) transferring the resist pattern into the underlying film or workpiece by using a dry or plasma assisted etching tool; And (6) some or all of the steps of removing the resist using a tool such as an RF or microwave plasma resist stripper.

Claims (21)

A method of forming a carbon layer on a surface of a semiconductor substrate in a processing chamber, comprising:
(a) introducing an aluminum-containing reactant into a processing chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond, introducing the aluminum-containing reactant into a processing chamber;
(b) introducing a carbon-containing reactant into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and the carbon-containing reactant comprises the aluminum-containing reactant and Introducing a different, carbon-containing reactant into the processing chamber;
(c) the aluminum-containing reactant and the carbon-containing reactant under conditions in which one or both of the aluminum-containing reactant and the carbon-containing reactant form an adsorption-limited layer on the surface of a semiconductor substrate Adsorbing at least one of them on the surface of the semiconductor substrate; And
(d) at least one of the aluminum-containing reactant and the carbon-containing reactant to form an adsorption-limited layer on the surface of the semiconductor substrate, and then to form a carbon layer on the surface of the semiconductor substrate. And reacting the aluminum-containing reactant with the carbon-containing reactant. A method of forming a carbon layer on the surface of a semiconductor substrate. The method of claim 1,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the aluminum-containing reactant having at least one aluminum-carbon bond is trialkylaluminum. The method of claim 1,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the aluminum-containing reactant having at least one aluminum-carbon bond is trimethylaluminum. The method of claim 1,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the carbon-containing reactant having at least one carbon-halogen bond is carbon tetrahalide. The method of claim 1,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the at least one carbon-halogen bond is a carbon-fluorine bond. The method of claim 1,
The aluminum-containing reactant is trialkylaluminum, and the carbon-containing reactant is selected from the group consisting of CX ₄ , CHX ₃ , CH ₂ X ₂ , and CH ₃ X, wherein X is halogen. How to form a carbon layer on the surface of the. The method of claim 6,
X is fluorine, the method of forming a carbon layer on the surface of a semiconductor substrate. The method of claim 6,
X is chlorine and/or bromine. A method of forming a carbon layer on the surface of a semiconductor substrate. The method of claim 1,
The step of reacting the aluminum-containing reactant with the carbon-containing reactant includes forming an aluminum-containing by-product, and the method further comprises removing the aluminum-containing by-product after step (d) A method of forming a carbon layer on the surface of a semiconductor substrate. The method of claim 7,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the aluminum-containing by-product comprises an aluminum-halogen bond. The method of claim 1,
The method of forming a carbon layer on the surface of a semiconductor substrate, wherein the surface of the semiconductor substrate on which the carbon layer is formed has patterned 3D features. The method of claim 1,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the aluminum-containing reactant forms an adsorption-limited layer prior to introducing the carbon-containing reactant. The method of claim 1,
The method of forming a carbon layer on a surface of a semiconductor substrate, wherein the carbon-containing reactant forms an adsorption-limited layer prior to introducing the aluminum-containing reactant. The method of claim 1,
Further comprising purging and/or evacuating the processing chamber to remove the aluminum-containing reactant or the carbon-containing reactant from the processing chamber between steps (a) and (b), A method of forming a carbon layer on the surface of a semiconductor substrate. The method of claim 1,
A method of forming a carbon layer on a surface of a semiconductor substrate, further comprising repeating the steps (a) to (d) to deposit the carbon layer to a predetermined thickness. The method of claim 1,
The method of forming a carbon layer on the surface of a semiconductor substrate, wherein the carbon layer is deposited in a gap filling operation. The method of claim 1,
The carbon layer is deposited in a gap filling operation in a partially fabricated 3D NAND structure. A method of forming a carbon layer on a surface of a semiconductor substrate in a processing chamber, comprising:
(a) introducing an aluminum-containing reactant into a processing chamber and forming a layer of the aluminum-containing reactant on the surface of a semiconductor substrate, wherein the aluminum-containing reactant has at least one aluminum-carbon bond. , Introducing the aluminum-containing reactant into a processing chamber and forming a layer;
(b) removing the aluminum-containing reactant from the processing chamber after step (a);
(c) introducing a carbon-containing reactant into the processing chamber and forming a layer of the carbon-containing reactant on the surface of the semiconductor substrate, wherein the carbon-containing reactant is at least one carbon-halogen Introducing the carbon-containing reactant into the processing chamber and forming a layer, having a bond, and wherein the carbon-containing reactant is different from the aluminum-containing reactant;
(d) removing the carbon-containing reactant from the processing chamber after step (c); And
(e) the aluminum-containing reactant layer and the carbon-containing reactant to activate a reaction between the aluminum-containing reactant and the carbon-containing reactant to form a carbon layer on the surface of the semiconductor substrate. A method of forming a carbon layer on a surface of a semiconductor substrate comprising the step of contacting said semiconductor substrate having a layer with a plasma. The method of claim 18,
The aluminum-containing reactant is trialkyl aluminum, the carbon-containing reactant is CF ₄ , and the reaction between the trialkyl aluminum and CF _{4 changes} the semiconductor substrate to helium (He), argon (Ar), and hydrogen. A method of forming a carbon layer on a surface of a semiconductor substrate, activated by contacting a plasma formed of a process gas containing a gas selected from the group consisting of (H ₂ ) and nitrogen (N ₂ ). A partially fabricated semiconductor substrate comprising a plurality of carbon spacers. A system for processing a semiconductor substrate, comprising:
(a) a processing chamber, the processing chamber having a substrate holder and one or more inlets for introduction of reactants into the processing chamber; And
(b) as a system controller,
(i) program instructions for inducing the introduction of an aluminum-containing reactant into the processing chamber, wherein the aluminum-containing reactant has at least one aluminum-carbon bond. Program instructions for;
(ii) program instructions for causing the introduction of a carbon-containing reactant into the processing chamber, wherein the carbon-containing reactant has at least one carbon-halogen bond, and the carbon-containing reactant is the aluminum- Program instructions for causing the introduction of the carbon-containing reactant into the processing chamber, different from the containing reactant;
(iii) the aluminum-containing reactant to the surface of the semiconductor substrate under conditions in which 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 program instructions for inducing adsorption of at least one of the carbon-containing reactants. And
(iv) at least one of the aluminum-containing reactant and the carbon-containing reactant to form an adsorption-limited layer on the surface of the semiconductor substrate, and then to form a carbon layer on the surface of the semiconductor substrate. And the system controller comprising program instructions for causing a reaction between the aluminum-containing reactant and the carbon-containing reactant.

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