CN112041980A - Low temperature molybdenum film deposition using boron nucleation layers - Google Patents

Low temperature molybdenum film deposition using boron nucleation layers Download PDF

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CN112041980A
CN112041980A CN201980027078.3A CN201980027078A CN112041980A CN 112041980 A CN112041980 A CN 112041980A CN 201980027078 A CN201980027078 A CN 201980027078A CN 112041980 A CN112041980 A CN 112041980A
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molybdenum
boron
nucleation layer
substrate
layer
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孟双
R·U·阿西翁
B·C·亨德里克斯
T·H·鲍姆
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Entegris Inc
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    • H01L21/70Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76841Barrier, adhesion or liner layers
    • H01L21/76871Layers specifically deposited to enhance or enable the nucleation of further layers, i.e. seed layers
    • H01L21/76876Layers specifically deposited to enhance or enable the nucleation of further layers, i.e. seed layers for deposition from the gas phase, e.g. CVD
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    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
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    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/06Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of metallic material
    • C23C16/08Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of metallic material from metal halides
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    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
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    • C23C16/405Oxides of refractory metals or yttrium
    • CCHEMISTRY; METALLURGY
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    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/455Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
    • C23C16/45523Pulsed gas flow or change of composition over time
    • C23C16/45525Atomic layer deposition [ALD]
    • C23C16/45527Atomic layer deposition [ALD] characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
    • HELECTRICITY
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    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H01L21/28008Making conductor-insulator-semiconductor electrodes
    • H01L21/28017Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon
    • H01L21/28026Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon characterised by the conductor
    • H01L21/28035Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon characterised by the conductor the final conductor layer next to the insulator being silicon, e.g. polysilicon, with or without impurities
    • H01L21/28044Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon characterised by the conductor the final conductor layer next to the insulator being silicon, e.g. polysilicon, with or without impurities the conductor comprising at least another non-silicon conductive layer
    • H01L21/28061Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon characterised by the conductor the final conductor layer next to the insulator being silicon, e.g. polysilicon, with or without impurities the conductor comprising at least another non-silicon conductive layer the conductor comprising a metal or metal silicide formed by deposition, e.g. sputter deposition, i.e. without a silicidation reaction
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/70Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
    • H01L21/71Manufacture of specific parts of devices defined in group H01L21/70
    • H01L21/768Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics
    • H01L21/76838Applying interconnections to be used for carrying current between separate components within a device comprising conductors and dielectrics characterised by the formation and the after-treatment of the conductors
    • H01L21/76841Barrier, adhesion or liner layers
    • H01L21/76853Barrier, adhesion or liner layers characterized by particular after-treatment steps

Abstract

The present disclosure relates to a method of manufacturing a molybdenum film using a boron nucleation layer and a molybdenum nucleation layer. The resulting molybdenum films have low resistivity, are substantially free of boron, and can be fabricated at reduced temperatures compared to conventional chemical vapor deposition processes that do not use boron or molybdenum nucleation layers. The molybdenum nucleation layer formed by this process can protect the substrate from MoCl5Or MoOCl4In favour of the subsequent CVD Mo growth on top of the molybdenum nucleation layerNuclei and enables Mo CVD deposition to be carried out at lower temperatures. The nucleation layer may also be used to control the grain size of subsequent CVD Mo growth and thus control the resistivity of the Mo film.

Description

Low temperature molybdenum film deposition using boron nucleation layers
Cross Reference to Related Applications
This application is a continuation of U.S. patent application No. 15/820,640 filed on 22.11/2017, which claims benefit of U.S. provisional application No. 62/425,704 filed on 23.11/2016, the disclosure of which is incorporated herein by reference in its entirety for all purposes.
Technical Field
The present disclosure relates to vapor deposited molybdenum films or layers that can be manufactured at lower process temperatures, but at deposition rates similar to those achieved using conventional high temperature vapor deposition conditions for molybdenum. The resulting molybdenum films or layers formed by low temperature deposition also have low resistivity and are useful in a variety of articles, such as semiconductor devices and display devices.
Background
Molybdenum is a low resistivity refractory metal that may potentially replace tungsten as a material for memory, logic chips, and other devices that use poly-metal gate electrode structures. The molybdenum-containing thin films can also be used in some organic light emitting diodes, liquid crystal displays, and also in thin film solar cells and photovoltaic devices. A thin molybdenum film may be used as the barrier film.
Various precursor and vapor deposition techniques have been used to deposit thin molybdenum films. Precursors include inorganic and organometallic reagents, and vapor deposition techniques can include Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) as well as various modifications, such as ultraviolet laser photolytic CVD, plasma-assisted CVD, and plasma-assisted ALD. CVD and ALD processes are increasingly being used because they can give excellent conformal step coverage over highly non-planar microelectronic device geometries, however the cost and complexity of plasma-assisted deposition systems and high temperature deposition systems can increase production costs and tool costs. High temperature processes may also damage previously deposited or underlying structures.
In a typical CVD process, precursors are passed over an optionally heated substrate (e.g., wafer) in a low or ambient pressure reaction chamber. The precursors react and/or decompose on the substrate surface to produce a thin film of the deposited material, such as molybdenum. Volatile by-products are removed by the gas flow through the reaction chamber. Some metal films are formed in CVD processes by providing two or more gases to a reaction chamber, where the reaction of the gases results in the deposition of a metal on a substrate. The deposited film thickness and uniformity depend on a coordination of various parameters such as: temperature, pressure, gas flow rate and mixing uniformity, chemical depletion effect and time.
Having deposited a refractory metal film on a substrate in a CVD process comprises: heating a substrate, such as silicon dioxide, to a temperature of about 500 ℃ to 800 ℃ in a closed chamber; treating the heated surface with a vaporized substance, such as molybdenum hexafluoride, for a short period of time to increase adhesion of the surface to a subsequently deposited molybdenum layer; purging any unreacted molybdenum hexafluoride from the chamber; and then depositing a molybdenum film by mixing hydrogen with some of the freshly vaporized molybdenum hexafluoride, thereby reducing the molybdenum hexafluoride, producing hf (g), and depositing some of the molybdenum on the heated surface. The high temperature of such deposition complicates the processing equipment and consumes the thermal budget of the temperature sensitive devices. Moreover, the toxicity of hf (g) and the associated elimination and safety equipment to handle hf (g) make this process expensive and complex.
At a high temperature of about 700 ℃, MoOCl is used4Or MoCl5As molybdenum precursor and H2As a reducing gas, a smooth, low resistivity molybdenum film with good step coverage can be deposited on the substrate by Chemical Vapor Deposition (CVD). These high temperature molybdenum films are useful, but a lower deposition temperature would be even more advantageous because it consumes less thermal budget for materials used to fabricate, for example, DRAM or photovoltaic devices, and because less expensive and complex equipment can be used to fabricate the films. MoOCl was observed when the temperature of the substrate was reduced to below 700 ℃ during the deposition process described above4And MoCl5The reaction temperature cut-off values of (A) were all about 550 ℃. At around this temperature, the film is coarseRoughness increases, film resistivity increases, and the film deposition rate decreases and eventually stops below the cut-off temperature. This cut-off temperature also limits the step coverage properties of the molybdenum film. Smooth, low resistivity molybdenum films with good step coverage are a highly beneficial quality of thin films used in semiconductor device fabrication.
There is a continuing need to produce molybdenum metal films and coatings on a variety of substrates at lower deposition temperatures and without the need for complex and expensive heating and vapor abatement equipment.
Disclosure of Invention
To overcome the problems of high temperature molybdenum processing, including forming a rough and high resistivity film between 550 ℃ and 700 ℃, a boron decomposition layer or boron nucleation layer is deposited on a substrate, followed by replacement of the boron decomposition layer or boron nucleation layer with a high quality molybdenum nucleation layer on the substrate at temperatures below 550 ℃. It was found that a molybdenum nucleation layer prepared in this manner protects the underlying substrate from, for example, MoCl5To facilitate nucleation of subsequent smooth CVD Mo growth on top and to enable CVD Mo deposition at lower temperatures. The molybdenum nucleation layer may also be used to control the grain size of the subsequent CVD growth of bulk molybdenum and thus control the resistivity of the final molybdenum film. In some cases, it can be seen by SEM that a high content of boron is found below the molybdenum layer, which increases the film resistivity. This is particularly problematic in cases where multiple alternating layers of boron and molybdenum are deposited. A solution to the problem of high temperature molybdenum film formation and the presence of large amounts of boron in the deposited molybdenum nucleation layer is through the interaction with molecules containing molybdenum and chlorine (e.g., MoOCl)4Or MoCl5) To consume or replace substantially all of the deposited solid boron nucleation layer on the substrate. This reaction forms a molybdenum nucleation layer, may occur in the presence or absence of a reducing gas such as hydrogen, and simultaneously replaces the boron nucleation layer. The resulting molybdenum nucleation layer lowers the cut-off temperature of the subsequent bulk Mo CVD film formation process, using, for example, a material containing MoOCl in the presence of a reducing gas such as hydrogen4Or MoCl5Vapor composition of (4), MoOCl4Has a cut-off temperature of 400 ℃ to 575 ℃ and MoCl5The cut-off temperature of (A) is from 450 ℃ to 550 ℃. Andusing MoOCl4Or MoCl5As molybdenum precursor and H2Molybdenum CVD films formed in this manner have low film resistivity, are smooth, and have better step coverage than molybdenum films deposited on a substrate by Chemical Vapor Deposition (CVD) of molybdenum as a reducing gas at high temperatures of about 700 ℃.
The present disclosure relates to compositions and a method of fabricating a molybdenum nucleation layer on a substrate. Optionally, the substrate itself may be a molybdenum nucleation layer. Alternatively, the substrate may be substantially free of molybdenum.
The method may include the act or step of reacting a pre-existing solid boron-containing nucleation layer on a substrate with a vapor composition comprising molecules containing molybdenum atoms and chlorine atoms. In some variations, the vapor composition is substantially free of reducing gases. The substrate is maintained at a temperature between 450 ℃ and 550 ℃ and reaction with the vapor consumes at least a portion of the boron nucleation layer while forming a molybdenum nucleation layer atop the substrate. In some variations, a molybdenum nucleation layer may be formed on a substrate maintained at a temperature between 450 ℃ and 480 ℃. In some variations, the deposited molybdenum nucleation layer may have a thickness of about 5 angstroms
Figure BDA0002733066330000031
To about 100 angstroms
Figure BDA0002733066330000032
A thickness within the range of (1). Suitably, the thickness of the deposited molybdenum nucleation layer may be in the range of about 5 angstroms to about 50 angstroms, optionally in the range of 5 angstroms to about 30 angstroms, for example in the range of about 5 angstroms to about 20 angstroms. A vapor composition comprising molecules of molybdenum and chlorine may be present in a reaction chamber having a heated substrate at a pressure of 10 torr to 60 torr (and in some variations, at a pressure of 20 torr to 40 torr).
One aspect of the present invention provides a method of manufacturing a molybdenum layer, the method comprising: reacting a boron-containing nucleation layer on a substrate with a vapor composition comprising a molecule containing molybdenum atoms and chlorine atoms, the substrate having a temperature between 450 ℃ and 550 ℃; the reaction consumes at least a portion of the boron nucleation layer and forms a molybdenum nucleation layer atop the substrate.
The thickness of the substantially consumed boron-containing nucleation layer may be about
Figure BDA0002733066330000033
To about
Figure BDA0002733066330000034
In the meantime. Suitably, the boron-containing nucleation layer may have a thickness in the range of about 5 angstroms to about 50 angstroms, optionally in the range of about 5 angstroms to about 30 angstroms, for example in the range of about 5 angstroms to about 20 angstroms.
Advantageously, the boron-containing nucleation layer is substantially consumed by the reaction such that the molybdenum layer comprises less than 5 wt% boron, optionally less than 1 wt% boron, as determined by elemental analysis.
Can be applied by heating B on the substrate2H6To form a boron nucleation layer as appropriate. In some variations, the substrate is heated to 300 ℃ to 450 ℃ during deposition of the boron nucleation layer. Other boron-containing precursors and conditions may be used to deposit the boron nucleation layer. For example, the same or substantially the same temperature (450 ℃ to 550 ℃) used for molybdenum deposition may be used for the deposition of the boron nucleation layer.
Thus. In some variations, the method includes depositing a boron-containing nucleation layer atop a substrate, the substrate having a temperature between 300 ℃ and 550 ℃.
The method may optionally comprise: depositing another boron-containing nucleation layer atop the molybdenum nucleation layer atop the substrate, the substrate having a temperature between 300 ℃ and 550 ℃; optionally between 300 ℃ and 450 ℃, and reacting the further boron-containing nucleation layer with a vapor composition comprising molecules containing molybdenum atoms and chlorine atoms, the temperature of the substrate being between 450 ℃ and 550 ℃; the reaction consumes at least a portion of the another boron nucleation layer and forms another molybdenum nucleation layer.
The thickness of the further boron-containing nucleation layer may suitably be at
Figure BDA0002733066330000041
To
Figure BDA0002733066330000042
In the meantime. Suitably, the thickness of the further boron-containing nucleation layer may be in the range of about 5 angstroms to about 50 angstroms, optionally in the range of about 5 angstroms to about 30 angstroms, for example in the range of about 5 angstroms to about 20 angstroms. The deposition thickness of the other boron-containing nucleation layer may be less than the deposition thickness of the boron-containing nucleation layer atop the substrate.
The method may include vapor depositing a boron-containing nucleation layer atop the substrate for a first period of time and vapor depositing another boron-containing nucleation layer for a second period of time, the second period of time being shorter than the first period of time.
The further boron-containing nucleation layer may be substantially consumed by the reaction such that the further molybdenum layer comprises less than 5 wt% boron, optionally less than 1 wt% boron, as determined by elemental analysis.
Advantageously, the steps of depositing and reacting may be repeated, thereby forming a plurality of further molybdenum nucleation layers.
Optionally, a molybdenum nucleation layer may be formed on the substrate maintained at a temperature between 450 ℃ and 480 ℃. Advantageously, the pressure of the vapor composition may be between 10 torr and 60 torr. The vapor composition may be substantially free of reducing gases.
It should be appreciated that the method may include fabricating a top molybdenum nucleation layer. The molybdenum nucleation layer or another molybdenum nucleation layer atop the substrate may constitute a top molybdenum nucleation layer.
Indeed, another variation of the method for fabricating the top molybdenum nucleation layer comprises: depositing a boron-containing nucleation layer atop the substrate or atop a molybdenum nucleation layer atop the substrate, wherein the temperature of the substrate or the molybdenum nucleation layer atop the substrate is between 300 ℃ and 550 ℃, optionally between 300 ℃ and 450 ℃; and subsequently reacting the boron-containing nucleation layer with a vapor composition comprising molecules containing molybdenum atoms and chlorine atoms, the temperature of the substrate being between 450 ℃ and 550 ℃.
Vapor composition and boronThe reaction between the layers consumes at least a portion of the boron nucleation layer and forms a top molybdenum nucleation layer. In a variation of the method, the boron-containing nucleation layer may be at a thickness of
Figure BDA0002733066330000043
To
Figure BDA0002733066330000044
In the meantime. Suitably, the boron-containing nucleation layer may have a thickness in the range of about 5 angstroms to about 50 angstroms, optionally in the range of about 5 angstroms to about 30 angstroms, for example in the range of about 5 angstroms to about 20 angstroms.
In some variations of the method of fabricating a top molybdenum layer on a substrate, consuming at least a portion of the boron nucleation layer substantially or completely consumes the boron nucleation layer. Consuming at least a portion of the boron nucleation layer may produce a volatile boron compound.
In various variations of the method of fabricating the top molybdenum nucleation layer, the steps of depositing a boron-containing nucleation layer (also referred to as a boron decomposition layer) and reacting the boron-containing nucleation layer with a vapor composition comprising molecules comprising molybdenum and chlorine may be repeated one or more times. The one or more molybdenum nucleation layers may be substantially free of boron, as determined by SEM analysis, elemental analysis, or resistivity measurements.
A method of fabricating a molybdenum nucleation layer may include vapor depositing a bulk molybdenum layer atop a top molybdenum nucleation layer at a temperature of 450 ℃ to 550 ℃. The molybdenum complexes can be used to vapor deposit bulk molybdenum layers. In certain variations, the molybdenum complex contains molybdenum and chlorine. In still other variations, the molybdenum complex may comprise MoCl5Or it may comprise MoOCl4
Suitably, the film may have a thickness of 200 angstroms or more, and the resistivity of the molybdenum film may be ± 20% of the resistivity of a substantially similar thickness ± 10% of the molybdenum film as measured at room temperature (RT, 20 ℃ -23 ℃), the substantially similar thickness ± 10% of the molybdenum film being deposited from the molybdenum complex at 700 ℃ on a substrate in the absence of a molybdenum nucleation layer.
In a variation of the method of fabricating a molybdenum film, the molybdenum film atop the substrate includes a topmost bulk molybdenum layer and one or more underlying molybdenum nucleation layers. The molybdenum film can have a resistivity of less than 25 μ Ω -cm for a molybdenum film layer thickness of 200 angstroms or greater, and in some variations, the molybdenum film has a resistivity of less than 20 μ Ω -cm for a molybdenum layer thickness of 200 angstroms or greater. The lower resistivity molybdenum film consumes less power and generates less heat than a device having a higher resistivity molybdenum film.
In other variations of the method of fabricating a molybdenum film, the molybdenum film atop the substrate includes a topmost bulk molybdenum layer and one or more underlying molybdenum nucleation layers. The molybdenum film atop the substrate has a resistivity of between 10 and 25 μ Ω -cm measured at room temperature (RT, 20-23 ℃), in some variations may have a resistivity of between 12 and 25 μ Ω -cm, and in some other variations may have a resistivity of between 10 and 20 μ Ω -cm for molybdenum films having a thickness of between 800 and 200 angstroms. In certain variations, the molybdenum film has a thickness of
Figure BDA0002733066330000051
To
Figure BDA0002733066330000052
In still other variations of the method of making a molybdenum film, the resistivity of the molybdenum film may be within ± 20% of the resistivity of a vapor deposited molybdenum film of a similar thickness of ± 10% deposited on a similar substrate at 700 ℃ measured at room temperature (RT, 20 ℃ -23 ℃).
One variation of a method of fabricating a molybdenum film on a substrate may include the acts or steps of: exposing the substrate to B at a temperature in a range of 250 ℃ to 550 ℃ and a pressure in a range of 10 Torr to 60 Torr2H6A gas; forming a solid boron nucleation layer on a surface of a substrate; exposing the boron nucleation layer to a vapor comprising molybdenum atoms and chlorine atoms at a temperature above 450 ℃ and converting the boron layer to a molybdenum nucleation layer and generating a boron compound, such as BCl3(g) Or BOCl (g); optionally repeating the first four steps one or more times to form additional molybdenum nucleation layers; and by H2Reduction ofA molybdenum complex comprising molybdenum atoms and chlorine atoms, CVD-depositing molybdenum atop the top molybdenum nucleation layer at a temperature of 550 ℃ or less.
Another variation of fabricating a molybdenum film on a substrate may include the acts or steps of: first, the substrate is exposed to B at a temperature ranging from 300 ℃ to 550 ℃ and a pressure ranging from 10 Torr to 60 Torr2H6In the gas. Forming a boron decomposition layer or a boron nucleation layer on the surface of the substrate, and the thickness of the layer can pass through B2H6Flow rate and dose time. The boron layer is then exposed to MoCl at a temperature greater than 450 deg.C5. The reaction converts the boron layer to a molybdenum nucleation layer, wherein the volatile gas contains BCl as a byproduct3(g) Or BOCl (g). The thickness of the resulting molybdenum nucleation layer depends on the starting thickness of the boron decomposition layer. The process of fabricating and converting the boron nucleation layer to a molybdenum nucleation layer may be repeated multiple times until the desired top molybdenum nucleation layer is obtained. Conventional CVD molybdenum deposition may then be performed on the top molybdenum nucleation layer. The molybdenum nucleation layer may help to lower the deposition cutoff temperature of CVD molybdenum from 550 ℃ to 450 ℃. CVD molybdenum films deposited on the top nucleation layer have low roughness and good step coverage over the deep via structure.
Variations of the method of manufacturing a molybdenum film may be performed in a fabrication process of forming a semiconductor device on a substrate. The molybdenum films of the present disclosure can also be deposited during the fabrication of various electronic, display, or photovoltaic devices. Examples of electronic devices include dynamic random access Devices (DRAMs) for digital storage devices and 3-D NAND logic gates for flash memory devices.
Detailed Description
The present disclosure relates to methods of fabricating molybdenum films on substrates using boron nucleation layers and molybdenum nucleation layers. The resulting molybdenum film may have low resistivity, may be substantially free of boron, and may be fabricated at reduced temperatures compared to conventional chemical vapor deposition processes that do not use a boron nucleation layer or a molybdenum nucleation layer. The molybdenum nucleation layer formed by this process can protect the substrate from chlorine-containing precursors (e.g., MoCl)5Or MoOCl4) Etching of, and may facilitate subsequent CVD Mo growth on molybdenumNucleation on top of the nucleation layer and molybdenum CVD deposition can be performed at lower temperatures. The molybdenum nucleation layer may also be used to control the grain size of the subsequent CVD molybdenum growth and thus control the resistivity of the final molybdenum film.
The substrate (which may include a thin superstrate film) may be formed by first exposing the substrate to B in a temperature range of 300 ℃ to 550 ℃ and a pressure range of 10 torr to 60 torr2H6The gas forms a boron nucleation layer. A solid nucleation or decomposition layer containing boron is formed on the substrate surface (or overlying film), and the thickness of the boron-containing nucleation or decomposition layer can pass through B2H6Flow rate and dose time. The boron-containing nucleation layer may have a thickness of
Figure BDA0002733066330000061
To
Figure BDA0002733066330000062
In the meantime. Suitably, the boron-containing nucleation layer may have a thickness in the range of about 5 angstroms to about 50 angstroms, optionally in the range of 5 angstroms to about 30 angstroms, for example in the range of about 5 angstroms to about 20 angstroms.
The molybdenum nucleation layer may be formed by exposing and reacting the boron nucleation layer to a vapor composition comprising molybdenum, chlorine, and optionally oxygen at an elevated temperature. This reaction with the vapor composition consumes the boron nucleation layer and replaces it with a molybdenum nucleation layer. The vapor composition may include MoCl5、MoOCl4Or other materials. For example, a substrate having a boron nucleation layer may be maintained at a temperature of 450 ℃ to 550 ℃ on a stage in a reactor, and may be exposed to a solution comprising MoCl5Or MoCl alone5Composition of, or exposure to, a composition that may include MoCl5A mixture with an inert gas, such as argon (Ar), or exposure may be to a composition including MoCl5With a reducing gas (e.g. hydrogen (H))2) A composition of a mixture of (a) and (b). In another example, a substrate on a heated stage having a boron nucleation layer may be maintained at a temperature of 450 ℃ to 550 ℃ and exposed to a solution comprising MoOCl4Or from MoOCl4The composition, or exposure, may be to a composition comprising MoOCl4A mixture with an inert gas, such as argon (Ar), or exposure may be to a composition including MoOCl4With a reducing gas (e.g. hydrogen (H))2) A composition of a mixture of (a) and (b). Exposing the boron nucleation layer to one or more of these compositions at temperatures of 450 ℃ to 550 ℃ may convert the boron nucleation layer to a molybdenum-containing nucleation layer.
BCl3Or other boron-containing volatile species may be generated as a byproduct of the conversion of the boron nucleation layer to the molybdenum nucleation layer. The cut-off temperature of the reaction was about 450 ℃.
In the presence of H2In the case of (3), the reaction by-products may include HCl, BCl3And OCl2(containing MoOCl in the vapor composition)4In the case of (1). The reaction may or may not be with H on the boron nucleation layer2In the case of co-reactants.
The thickness of the resulting molybdenum nucleation layer depends on the starting thickness of the boron nucleation layer. In some variations, a vapor composition including molybdenum, chlorine, and optionally oxygen, but not including a reducing gas, may be used to convert the boron nucleation layer to a molybdenum nucleation layer. The thickness of the resulting molybdenum nucleation layer is proportional to the thickness of the boron nucleation layer.
Advantageously, the steps of depositing a boron nucleation layer and reacting the boron nucleation layer to form a molybdenum nucleation layer may be repeated to form one or more further boron nucleation layers.
Where multiple boron nucleation layers are formed, these layers may be made in substantially the same manner. Alternatively, different layers may employ different conditions, e.g., as described elsewhere herein.
The method may include fabricating a top molybdenum nucleation layer. The molybdenum nucleation layer or another molybdenum nucleation layer atop the substrate may constitute a top molybdenum nucleation layer.
Variations of the molybdenum film formation process may further include the act or step of vapor depositing a molybdenum complex on the top molybdenum nucleation layer on the substrate to form a bulk molybdenum layer. The bulk molybdenum layer and one or more underlying molybdenum nucleation layers form a molybdenum film having
Figure BDA0002733066330000071
To
Figure BDA0002733066330000072
A thickness within the range of (1); in some variations, the thickness of the molybdenum film may be within
Figure BDA0002733066330000073
To
Figure BDA0002733066330000074
In the meantime. The temperature of the substrate during this bulk vapor deposition action or step may be between 450 ℃ and 550 ℃. In some variations, the molybdenum complex may be a vapor composition comprising a molybdenum atom and a chlorine atom, and in other cases, the molybdenum complex may be a vapor composition comprising a molybdenum atom, a chlorine atom, and an oxygen atom. Examples of molybdenum complexes that can be used in variations of the method include MoCl5And MoOCl4
A composition comprising a molecule containing a molybdenum atom and a chlorine atom or a molybdenum complex containing a molybdenum atom and a chlorine atom may be vaporized to produce a vapor composition containing a molybdenum atom and a chlorine atom for use in a molybdenum film formation method. The composition or complex may each comprise MoCl5(in some variations, 99% or greater molecular purity) or MoOCl4(in some variations 99% or greater molecular purity). In some variations, the molybdenum complex may be an organometallic molybdenum compound containing a cyclopentadienyl group and other ligands. The molybdenum complex can be purified by sublimation to a molecular purity of greater than 99.99%. For example, MoCl5Can be purified by sublimation to remove traces of higher vapor pressure MoOCl4. Variations of the present disclosure may include an ampoule suitable for use in a vapor deposition process, the ampoule containing MoCl having a molecular purity greater than 99.99%5. Another variation of the disclosure may include an ampoule suitable for use in a vapor deposition process, the ampoule containing MoOCl having a molecular purity greater than 99.99%4. Sublimation can be used to purify MoCl5Or MoOCl4And removing unwanted metal halides and metal oxyhalides.
In a variation of the method of fabricating a molybdenum film, reference to the boron nucleation layer being substantially consumed may mean that no boron is visible by SEM analysis of a cross-section of a sample in which the one or more boron nucleation layers are replaced by the one or more molybdenum nucleation layers. Substantially consumed may additionally or alternatively refer to the presence of less than 5 wt%, and in some cases less than 1 wt%, boron in the molybdenum film and any underlying molybdenum nucleation layer. The boron content can be determined by dissolving the film from the substrate acid and measured by elemental analysis. Substantially consumed may also refer to a molybdenum film having a resistivity in the range of 20% or less of a molybdenum layer of similar thickness (+ -10%) as measured at room temperature (RT, 20 ℃ -23 ℃), said molybdenum layer of similar thickness (+ -10%) being formed from MoCl at 700 ℃5Vapor deposited on similar substrates.
Thermal budget refers to the cumulative thermal energy imparted to a semiconductor microelectronic transistor, logic gate, or photovoltaic device by all thermal processing steps during fabrication. Controlling the thermal budget of the process helps prevent dopant redistribution in the joints and diffusion of metal through the barrier layer. If high temperatures are required during fabrication, a reasonable thermal budget can be achieved by limiting the duration of the process. Similarly, if the process takes a long time to complete, the temperature may be lowered to avoid excessive thermal budget. In a variation of the method, the molybdenum nucleation layer and the bulk molybdenum layer may be deposited at a temperature below 500 ℃ and with similar deposition times as compared to a 700 ℃ molybdenum process without the Mo nucleation layer. The lower deposition temperature of the new methods disclosed herein can be used to reduce the thermal budget requirements for processes in which molybdenum films are used in semiconductor device fabrication. In addition, the lower process temperatures achieved by the current processes can reduce costs by allowing the use of less expensive process equipment and designs.
In a variation of the method of manufacturing a molybdenum film, the decomposition or nucleation layer comprising boron is substantially free of borides. Similarly, the molybdenum nucleation layer and the molybdenum film are substantially free of borides. Borides are materials formed between boron and a more electronegative element, such as silicon. The boride layer has been coatedAre suggested as barrier layers in the fabrication of integrated circuits to inhibit the diffusion of metals and other impurities into the regions underlying the barrier layers. Borides are typically formed using Chemical Vapor Deposition (CVD) techniques. For example, CVD may be used to react tetrachloroated metal with diborane to form diboride metal. However, when chlorine-based chemicals are used to form boride barrier layers, reliability issues can arise. In particular, boride layers formed using CVD chlorine-based chemistries typically have high chlorine content (e.g., chlorine content greater than about 3%). High chlorine content is undesirable because chlorine may migrate from the boride barrier layer into adjacent interconnect layers, which may increase the contact resistance of such interconnect layers and potentially alter the characteristics of the integrated circuits fabricated therefrom. It has been found that the molybdenum films prepared by the methods disclosed herein protect the substrate from MoCl5、MoOCl4The etching effect of (1).
In various variations of forming a molybdenum film atop a substrate, bulk molybdenum, a molybdenum nucleation layer, and a boron nucleation layer may be deposited by vapor deposition. Vapor deposition includes any of Chemical Vapor Deposition (CVD), Atomic Layer Deposition (ALD), high and low pressure variations of these depositions, and variations of the assist variations of these depositions including, for example, but not limited to, plasma enhanced CVD, laser assist, and microwave assist.
In some variations of the present disclosure, there is a layer of material overlying the substrate. This layer may be, for example, but not limited to, titanium nitride, molybdenum, or other material underlying a bulk molybdenum layer in a semiconductor device. For example, when using a refractory element metal such as molybdenum in a polysilicon-to-metal gate electrode structure, a thin conductive diffusion barrier layer may be provided between the polysilicon and the element metal to prevent silicidation of the element metal during high temperature processing. The diffusion barrier layer is typically composed of a conductive metal nitride, such as tungsten nitride (WN), titanium nitride (TiN), tantalum nitride (TaN), and/or corresponding silicon-containing ternary compounds, such as WSiN, TiSiN, and TaSiN.
In some variations, the substrate includes a molybdenum nucleation layer, such as a pre-formed molybdenum nucleation layer in accordance with the present invention.
Substrates that may be used in variations of the method include silicon, silicon oxide, gallium arsenide, aluminum oxide, and other ceramics and metals having suitable chemical and temperature characteristics.
The boron nucleation layer or boron decomposition layer may have a thickness of about 5 angstroms
Figure BDA0002733066330000091
To about 100 angstroms
Figure BDA0002733066330000092
A thickness within the range of (1). The molybdenum nucleation layer may have a thickness of about 5 angstroms
Figure BDA0002733066330000093
To about 100 angstroms
Figure BDA0002733066330000094
A thickness within the range of (1). The boron nucleation layer may be deposited on the substrate or on a layer on top of the substrate that is heated to a temperature above 250 ℃ to a temperature including between 550 ℃. In some variations, the boron nucleation layer may be deposited on the substrate or on a layer on top of the substrate that is heated to a temperature above 300 ℃ to a temperature including between 450 ℃. The boron nucleation layer fabricated between above 300 ℃ and up to and including 450 ℃ provides a smooth bulk molybdenum layer with low resistivity. The one or more B2H6The nucleation layer may be formed by exposing the substrate to B at a temperature in a range of 300 ℃ to 550 ℃ and a pressure in a range of 10 Torr to 60 Torr2H6Gas deposition.
Bulk molybdenum vapor deposition from a molybdenum complex onto the top nucleation layer may occur in the presence of a reducing gas such as hydrogen. For example, by selecting from a group having N2Or sublimation of Ar-bearing gas stream in a vessel or ampoule5The complex is delivered to the reaction chamber. For example, an ampoule containing molybdenum pentachloride as a complex may be heated to a temperature between 70 ℃ and 100 ℃. The vaporization temperature will vary depending on the molybdenum complex used. Lower ampoule temperatures favor the generation of all vapors because it can reduce the decomposition of the molybdenum complex and thereby provide moreResulting in a molybdenum deposition rate.
Example 1
This example shows on a substrate
Figure BDA0002733066330000095
Molybdenum is deposited on top of the thick titanium nitride layer. The thickness of the titanium nitride layer after deposition of the molybdenum nucleation layer and bulk molybdenum was within 20% of the thickness of the TiN layer initially measured, suggesting that the molybdenum nucleation layer provides etch resistance to the underlying TiN generated by chlorine-containing precursors and by-products.
The molybdenum film on top of the substrate was deposited by a multi-step process at different temperatures and pressures, as detailed in table 1 below. The first step comprises the following substeps: in SiO2Depositing a solid boron nucleation layer on the titanium nitride layer on top of the substrate; and exposing the solid boron nucleation layer (or boron decomposition layer) to a solution comprising MoCl5And hydrogen, thereby causing the boron nucleation layer to be substantially replaced by the molybdenum nucleation layer.
The next step is to deposit a new boron nucleation layer atop the molybdenum nucleation layer within a shorter soak time than the first boron layer nucleation, and then a bulk molybdenum deposition, which is initiated by: substantially consuming new boron nucleation to form molybdenum; followed by MoCl5And H2Seamlessly bulk depositing molybdenum to form a molybdenum film on the substrate.
The resistivity of the film was measured at room temperature (RT, 20 ℃ to 23 ℃).
TABLE 1
Figure BDA0002733066330000101
As detailed in table 1, the deposition temperature of the molybdenum nucleation layer is carried out at a temperature of 480 ℃ to 450 ℃, and in particular at a temperature of 480 ℃, 460 ℃ or 450 ℃. The pressure of the nucleated molybdenum or bulk molybdenum deposition step was varied between 10 torr and 40 torr. MoCl5The ampoule temperature (Amp temperature ℃ C.) was 90 ℃.
The results of this example show that at a process pressure of 10 torr, little or no Mo deposition is obtained at 480 ℃. However, it is not limited toMo film deposition rate of about 40 Torr
Figure BDA0002733066330000102
Or thicker films, and the deposition rate decreases with decreasing deposition temperature. The molybdenum deposition rate was about 480 ℃ and 40 torr pressure
Figure BDA0002733066330000103
The molybdenum deposition rate was about 460 ℃ and 40 torr pressure
Figure BDA0002733066330000104
And a molybdenum deposition rate of about 460 ℃ and 40 torr pressure
Figure BDA0002733066330000105
The results of this example also show that the molybdenum films produced comprised a bulk molybdenum layer and one or more molybdenum nucleation layers, and that the four-point resistivity of the bulk molybdenum layer and the one or more molybdenum nucleation layers, measured at room temperature (RT, 20 ℃ -23 ℃), was between 12 μ Ω · cm and 20 μ Ω · cm for molybdenum films having a thickness of 700 angstroms to 300 angstroms, respectively. All films showed low resistivity below 20 μ Ω · cm when measured at room temperature (RT, 20 ℃ -23 ℃).
Example 2
This comparative example shows the deposition of molybdenum on a substrate without a molybdenum nucleation layer. Deposition was tested at stage temperatures of 550 ℃ to 700 ℃ and deposition times varied from 30 seconds to 600 seconds. In SiO2On top of the substrate
Figure BDA0002733066330000106
On the TiN layer of (2) is subjected to MoCl5To form Mo. Adding MoCl5The ampoule is heated to 70 ℃ and the pressure in the chamber is 60 torr H2The flow rate was 2000sccm and the argon carrier gas flow was 50 sccm.
The results in Table 2 show that MoCl was used at stage temperatures above 550 deg.C5/H2CVD deposition of Mo films was achieved on TiN coated substrates. At lower temperatures (e.g.<550 ℃ objective tableTemperature) due to MoCl5The substrate etching effect and nucleation of Mo are insufficient and Mo stops depositing.
TABLE 2
Figure BDA0002733066330000111
The results of this example show that at the same deposition time of about 180 seconds, the deposited molybdenum film thickness is from 700 ℃ C
Figure BDA0002733066330000112
(deposition rate of
Figure BDA0002733066330000113
) Reduced to 600 deg.C
Figure BDA0002733066330000114
(deposition rate of
Figure BDA0002733066330000115
) And as low as 550 ℃ C
Figure BDA0002733066330000116
(deposition rate of
Figure BDA0002733066330000117
). For films of similar thickness prepared at different temperatures, the resistivity of the molybdenum films measured at room temperature (RT, 20 ℃ -23 ℃) increases with decreasing deposition temperature. For example, deposited at 550 ℃
Figure BDA0002733066330000118
The resistivity of the thick Mo film is 60 mu omega cm; deposited at 600 DEG C
Figure BDA0002733066330000119
Thick Mo film resistivity of 30.3. mu. omega. cm, deposited at 700 deg.C
Figure BDA00027330663300001110
The resistivity of the thick film was 21.8. mu. omega. cm.
Example 3
This example shows fabrication of a semiconductor device including one or more molybdenum nucleation layers and a semiconductor layer made of MoCl5A molybdenum film of a bulk molybdenum layer deposited by vapor deposition.
The resulting molybdenum films were prepared and characterized as detailed in table 3. The substrate used is in SiO2Is provided with on the top
Figure BDA00027330663300001111
The titanium nitride layer of (2). At a stage temperature of 300 deg.C, a chamber pressure of 40 Torr, B of 35sccm2H6Performing formation of a solid boron nucleation layer on the TiN layer at a flow rate and an argon flow rate of 250 sccm; the time varies between 60 seconds and 30 seconds depending on whether the boron nucleation layer is formed on the TiN or the initial molybdenum nucleation layer. The estimated thickness of the boron nucleation layer is 5 to 30 angstroms.
MoCl5The ampoule temperature is 90 deg.C, the chamber pressure is 20 Torr, the argon carrier gas flow is 100sccm, H22000sccm and stage temperatures varied from 480 ℃ to 500 ℃. The reaction time varies between 30 and 600 seconds depending on whether the molybdenum nucleation layer is formed by consuming the initial boron nucleation layer or the second molybdenum nucleation layer is formed after bulk Mo CVD.
TABLE 3
Figure BDA0002733066330000121
These molybdenum films have a resistivity measured at room temperature of between 12 μ Ω -cm and 25 μ Ω -cm for molybdenum layers having a thickness of 800 to 200 angstroms, respectively.
The results of this example further show that low resistivity molybdenum films can be produced at substrate temperatures of 480 ℃ to 500 ℃ by consuming the boron nucleation layer by reaction of the boron-containing nucleation layer on the substrate with a vapor composition comprising molecules containing molybdenum atoms and chlorine atoms. The resistivity of the bulk molybdenum film in this example is 20% of the resistivity of a substantially similar thickness (+ -10%) bulk molybdenum layer measured at room temperatureBulk molybdenum layers of similar thickness (+ -10%) were deposited from the same molybdenum complex at 700 ℃ on similar substrates without the molybdenum nucleation layer. For example, molybdenum was deposited on a similar substrate using the molybdenum complex of sample 322-237-12 in example 2 for
Figure BDA0002733066330000122
The film was thick, and a resistivity of about 16.1. mu. omega. cm was obtained.
Example 4
This example illustrates the deleterious effect of excess residual boron on the resistivity of molybdenum films deposited with boron nucleation layers and the cut-off temperature for molybdenum deposition using boron nucleation layers.
The thickness of molybdenum after deposition at substrate temperatures of 450 ℃, 500 ℃ and 550 ℃ was measured after 1, 2, 3, 4, 5 cycles. The thickness of the molybdenum film at a deposition temperature of 450 ℃ after 5 nucleation cycles is less than
Figure BDA0002733066330000123
After 5 nucleation cycles, the molybdenum film thickness at a deposition temperature of 500 ℃ was about
Figure BDA0002733066330000124
After 5 nucleation cycles, the molybdenum film thickness at a deposition temperature of 550 ℃ was about
Figure BDA0002733066330000125
Based on these results, MoCl was determined5The cut-off temperature for the reaction with boron will be between 450 ℃ and 500 ℃.
The molybdenum film resistivity measured at room temperature after deposition at substrate temperatures of 500 ℃ and 550 ℃ was measured after 1, 2, 3, 4, 5 cycles. The resistivity after 1 nucleation cycle at 500 ℃ was too high to be measured, while the resistivity of the molybdenum film after 1 nucleation cycle at 550 ℃ was about 310 μ Ω · cm. The resistivity of the molybdenum film after 2 nucleation cycles at 500 ℃ was about 250 μ Ω -cm, while the resistivity of the molybdenum film after 2 nucleation cycles at 550 ℃ was about 275 μ Ω -cm. The resistivity of the molybdenum film after 5 nucleation cycles at 500 ℃ was about 250 μ Ω -cm, while the resistivity of the molybdenum film after 5 nucleation cycles at 550 ℃ was about 340 μ Ω -cm. In this example, the resistivity after 2 nucleation cycles was much higher than a similar film made after 2 nucleation cycles in example 1, and without wishing to be bound by theory, this is believed to be due to the presence of boron in the film.
Example 5
This example shows the deposition of molybdenum on a substrate without a boron nucleation layer with a TiN layer. Heating the substrate to 700 ℃ on a stage in the reactor and using a reactor containing MoCl5The combination of the vapor and varying amounts of hydrogen gas treats the substrate. The process conditions included an inert argon flow of 50sccm, a chamber pressure of 60 torr, a low hydrogen flow rate of 2000sccm, and a high hydrogen flow rate of 4000 sccm.
The results of this example show that the resistivity of a molybdenum film deposited on a substrate without a nucleation layer was measured at 4 points without a boron nucleation layer deposited
Figure BDA0002733066330000131
From 15 to 23 mu omega cm of thick molybdenum films to films without a boron nucleation layer deposited
Figure BDA0002733066330000132
The thick molybdenum film is in a range of about 10 to 16 μ Ω -cm. All membranes prepared using higher hydrogen flow rates had lower resistivity than the membranes prepared at the lower hydrogen flow rates, and for about
Figure BDA0002733066330000133
Thick molybdenum films, the resistivity of the films produced at higher hydrogen flow rates was about 5 μ Ω cm lower than the samples produced at lower hydrogen flow rates. The molybdenum film resistivity decreases with increasing film thickness.
While various compositions and methods are described, it is to be understood that this invention is not limited to the particular molecules, compositions, designs, methods or protocols described, as these may vary. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims.
It must also be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a nucleation layer" is a reference to one or more nucleation layers and equivalents thereof known to those skilled in the art, and so forth. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention. All publications mentioned herein are incorporated by reference in their entirety. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention. "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. All numerical values herein may be modified by the term "about", whether or not explicitly indicated. The term "about" generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In some embodiments, the term "about" refers to the value ± 10%, and in other embodiments, the term "about" refers to the value ± 2%. While compositions and methods are described in terms of "comprising" (interpreted as meaning "including, but not limited to") various components or steps, the compositions and methods can also "consist essentially of" or "consist of" the various components and steps, and such terms should be interpreted as defining essentially closed or closed groups of elements.
Although the invention has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The present invention includes all such modifications and alterations and is limited only by the scope of the following claims. In addition, while a particular feature or aspect of the invention may have been disclosed with respect to only one of several implementations, such feature or aspect may be combined with one or more other features or aspects of the other implementations as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the terms "includes," has, "" with, "or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term" comprising. Additionally, the term "exemplary" is merely meant as an example, and not the best. It will also be appreciated that for simplicity and ease of understanding, the features, layers, and/or elements depicted herein are shown in particular sizes and/or orientations with respect to one another, and that the actual sizes and/or orientations may differ substantially from those shown herein.

Claims (20)

1. A method of fabricating a molybdenum layer, the method comprising:
reacting a boron-containing nucleation layer on a substrate with a vapor composition comprising a molecule containing molybdenum atoms and chlorine atoms, the substrate having a temperature between 450 ℃ and 550 ℃; the reaction consumes at least a portion of the boron nucleation layer and forms a molybdenum nucleation layer atop the substrate.
2. The method of claim 1, wherein the boron-containing nucleation layer has a thickness of about
Figure FDA0002733066320000011
To about
Figure FDA0002733066320000012
In the meantime.
3. The method of claim 1, wherein the boron-containing nucleation layer is substantially consumed by the reaction such that, by elemental analysis, the molybdenum layer comprises less than 5 wt% boron, optionally less than 1 wt% boron.
4. The method of claim 1, comprising depositing the boron-containing nucleation layer atop the substrate, the substrate having a temperature between 300 ℃ and 550 ℃.
5. The method of claim 1, further comprising:
depositing another boron-containing nucleation layer atop the molybdenum nucleation layer atop the substrate, the substrate having a temperature between 300 ℃ and 550 ℃; and
reacting the further boron-containing nucleation layer with a vapor composition comprising molecules containing molybdenum atoms and chlorine atoms, the temperature of the substrate being between 450 ℃ and 550 ℃; the reaction consumes at least a portion of the another boron nucleation layer and forms another molybdenum nucleation layer.
6. The method of claim 5, wherein the thickness of the other boron-containing nucleation layer is about
Figure FDA0002733066320000013
To about
Figure FDA0002733066320000014
In the meantime.
7. The method of claim 5, wherein the further boron-containing nucleation layer is deposited to a thickness less than the thickness of the boron-containing nucleation layer atop the substrate.
8. The method of claim 5, comprising vapor depositing the boron-containing nucleation layer atop the substrate for a first period of time, and vapor depositing the other boron-containing nucleation layer for a second period of time, the second period of time being shorter than the first period of time.
9. The method of claim 5, wherein the further boron-containing nucleation layer is substantially consumed by the reaction such that, by elemental analysis, the further molybdenum layer comprises less than 5 wt% boron, optionally less than 1 wt% boron.
10. The method of claim 5, wherein the steps of depositing and reacting are repeated to form a plurality of additional molybdenum nucleation layers.
11. The method of claim 1 wherein the temperature of the substrate during the reaction of the boron-containing nucleation layer is between 450 ℃ and 480 ℃.
12. The method of claim 1, wherein the vapor composition has a pressure between 10 torr and 60 torr.
13. The method of claim 1, wherein the vapor composition is substantially free of reducing gases.
14. The method of claim 1, wherein the or another molybdenum nucleation layer atop the substrate constitutes a top molybdenum nucleation layer.
15. The method of claim 14, comprising vapor depositing a molybdenum complex at a temperature of 450 ℃ to 550 ℃ to form a bulk molybdenum layer atop the top molybdenum nucleation layer.
16. The method of claim 15, wherein the molybdenum complex comprises MoCl5Or MoOCl4
17. The method of claim 15, wherein the thickness of the molybdenum film is 200 angstroms or greater and the resistivity of the bulk molybdenum layer is ± 20% of the resistivity of a bulk molybdenum layer of substantially similar thickness ± 20%, the substantially similar thickness ± 20% bulk molybdenum layer being deposited from the molybdenum complex at 700 ℃ on a substrate in the absence of the molybdenum nucleation layer.
18. The method of claim 15, comprising fabricating a molybdenum film comprising the bulk molybdenum layer and one or more molybdenum nucleation layers, the film having a resistivity measured at room temperature of less than 20 μ Ω -cm for a molybdenum film thickness of 200 angstroms or greater.
19. The method of claim 1, wherein the substrate includes one or more molybdenum nucleation layers.
20. The method of claim 1, wherein the substrate comprises a semiconductor substrate.
CN201980027078.3A 2018-04-20 2019-04-17 Low temperature molybdenum film deposition using boron nucleation layers Pending CN112041980A (en)

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