阅读说明：本技术 使用双(烷基芳烃)钼前体的钼气相沉积 (Vapor deposition of molybdenum using bis (alkylaromatic) molybdenum precursors ) 是由 R·小赖特 孟双 B·C·亨德里克斯 T·H·鲍姆 P·S·H·陈 于 2019-01-15 设计创作，主要内容包括：本发明描述通过使用双(烷基芳烃)钼作为用于这类沉积的前体将钼材料沉积到衬底上的气相沉积方法,所述双(烷基芳烃)钼在本文中又称为(烷基芳烃)<Sub>2</Sub>Mo,例如双(乙基苯)钼((EtBz)<Sub>2</Sub>Mo)；以及含有所沉积材料的结构。(The present invention describes vapor deposition methods for depositing molybdenum materials onto substrates by using bis (alkylaromatic) molybdenum, also referred to herein as (alkylaromatic), as a precursor for such deposition 2 Mo, e.g. molybdenum bis (ethylbenzene) ((EtBz) 2 Mo); and structures containing the deposited material.)

1. A method of forming a molybdenum-containing material on a substrate, the method comprising contacting the substrate with a bis (alkylaromatic) molybdenum vapor under vapor deposition conditions to deposit a molybdenum-containing material onto the substrate.

2. The process of claim 1, wherein the bis (alkylaromatic) molybdenum is bis (ethylbenzene) molybdenum ((EtBz)₂Mo)。

3. The method of claim 1, wherein the molybdenum-containing material is molybdenum carbide.

4. The method of claim 3, comprising depositing the molybdenum carbide onto the substrate by chemical vapor deposition at a substrate temperature of not greater than 300 degrees Celsius.

5. The method of claim 3, comprising depositing the molybdenum carbide onto the substrate in a deposition chamber having an internal pressure between 10 and 50 torr.

6. The method of claim 3, comprising depositing the molybdenum carbide as a seed layer having a thickness in a range of 6 to 100 angstroms.

7. The method of claim 3, wherein the molybdenum carbide comprises carbon and molybdenum in an atomic ratio of 1:99 to 60:40 (carbon: molybdenum).

8. The method of claim 3, wherein the molybdenum carbide is deposited onto a surface of the substrate comprising titanium nitride.

9. The method of claim 3, wherein the molybdenum carbide is deposited onto a three-dimensional surface of the substrate.

10. The method of claim 9, wherein the three-dimensional surface is a feature of 3DNAND comprising vertical walls separated by slots, the walls comprising horizontally extending ribs and recesses, and the method may comprise depositing a layer of molybdenum over surfaces of ribs and recesses.

11. The method of claim 9, wherein the three-dimensional surface comprises openings having an aspect ratio of longitudinal to lateral dimensions in a range of 2:1 to 200: 1.

12. The method of claim 3, comprising depositing metallic molybdenum onto the molybdenum carbide.

13. The method of claim 12, wherein the metallic molybdenum is derived from a molybdenum halide precursor or a molybdenum oxyhalide precursor.

14. The process of claim 12, wherein the metallic molybdenum is derived from molybdenum pentachloride (MoCl)₅) Molybdenum tetrachloride (MoOCl)₄) And molybdenum hexafluoride (MoF)₆) A precursor of (2).

15. The method of claim 12, comprising depositing the metallic molybdenum onto the substrate by chemical vapor deposition at a substrate temperature of at least 50 degrees celsius that is less than a temperature required to deposit elemental molybdenum onto a substrate that does not include the molybdenum carbide.

16. The method of claim 12, wherein the metallic molybdenum has a thickness of at least 50 angstroms.

17. The method of claim 1, wherein the molybdenum-containing material is metallic molybdenum.

18. The method of claim 17, comprising depositing elemental molybdenum at a thickness of at least 50 angstroms.

19. A substrate, comprising:

a molybdenum carbide seed layer deposited onto the titanium nitride, the molybdenum carbide seed layer derived from a bis (alkylaromatic) molybdenum precursor, and

a metallic molybdenum deposited on the seed layer, the metallic molybdenum derived from a molybdenum halide precursor or a molybdenum oxyhalide precursor.

Technical Field

The present invention relates to vapor deposition methods for depositing molybdenum-containing materials onto a substrate by using bis (alkylaromatic) molybdenum, also referred to herein as (alkylaromatic)₂Mo, e.g. molybdenum bis (ethylbenzene) ((EtBz)₂Mo) as a precursor for such deposition.

Background

Semiconductor and microelectronic devices and methods of making these devices are related to metals and metal-containing materials used in device structures such as electrodes, vias, barrier layers, interconnects, seed layers, and various other structures. During manufacturing, the metal or metal-containing material is placed onto the device by deposition, meaning, for example, by atomic layer deposition, chemical vapor deposition, or modifications or derivatives thereof. The deposition material is provided to the deposition process in the form of a "precursor," which may be an inorganic or organometallic agent that, when evaporated and exposed to a substrate under the appropriate conditions, will deposit onto the substrate, either alone or in combination with another material.

One metal commonly used for conductive structures is tungsten. Tungsten hexafluoride (WF) is introduced according to the usual method for depositing tungsten₆) Used as a precursor for the derivatization of deposited tungsten. Tungsten deposited by using tungsten hexafluoride has disadvantages in that fluorine and hydrogen (H)₂) React to form Hydrogen Fluoride (HF), which can be detrimental to the substrate, for example, by causing etching of the silicon wafer.

Molybdenum is a low resistivity refractory metal that has been used in microelectronic devices, for example, as a replacement for tungsten. Molybdenum has a high melting point, high thermal conductivity, low coefficient of thermal expansion, and low electrical resistivity. Molybdenum has been used or proposed for use as a diffusion barrier, electrode, light shield, interconnect, or as a low resistivity gate structure. Molybdenum is a candidate for replacing tungsten used in memory chips, logic chips, and other devices that include poly-metal gate electrode structures. Molybdenum containing thin films are also useful in organic light emitting diodes, liquid crystal displays, and thin film solar cells and photovoltaic devices.

Various precursor materials and vapor deposition techniques have been used to deposit metallic materials onto microelectronic device substrates. The deposition techniques may include Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) as well as various modifications of these processes, such as UV laser photo-dissociation CVD, plasma-assisted CVD, and plasma-assisted ALD. CVD and ALD processes are increasingly being used in the microelectronics industry because these methods can allow excellent conformal step coverage over highly non-planar microelectronic device geometries.

Researchers in the semiconductor and microelectronic industries are continually seeking improved materials and methods for depositing metals onto substrates to provide suitable metal or metal-containing layers and structures. Researchers are currently interested in methods and materials that circumvent tungsten hexafluoride, including the use of metals other than tungsten, such as molybdenum. Some materials and techniques have been described that are suitable for chemical vapor deposition of molybdenum. See, e.g., International patent publication No. WO2017/143246(PCT/US 2017/018455). The research work continues towards the following: other suitable materials and techniques are identified for use in vapor deposition processes for depositing molybdenum onto microelectronic device substrates.

Disclosure of Invention

Applicants have determined, in light of the following description, that molybdenum materials can be deposited onto microelectronic substrate surfaces by using bis (alkylaromatic) molybdenum compounds, also referred to herein as (alkylaromatics), as molybdenum precursors in deposition processes₂Mo, e.g. molybdenum bis (ethylbenzene) ((EtBz)₂Mo). Molybdenum may be deposited in any form or structure suitable for use as part of a microelectronic device substrate, for example, as a seed layer containing molybdenum in combination with another material (e.g., carbon to form molybdenum carbide), or as a conductive bulk molybdenum structure (i.e., elemental molybdenum).

Other potential molybdenum precursors under development, such as molybdenum halide and molybdenum oxyhalide precursors, have been shown to be effective in depositing very high purity metallic molybdenum films with very low resistivity. However, it has been found that the use of these precursors to nucleate metallic molybdenum films on titanium nitride or other desired substrate surfaces can be limited. Seed or nucleation layers from molybdenum halide and molybdenum oxyhalide precursors that will improve the nucleation of metallic molybdenum on a substrate would be expected to facilitate the use of these precursors for the deposition of extremely high purity metallic molybdenum films with extremely low resistivity.

According to the described vapour deposition method, the substrate can be obtained by reacting a substrate with a source of (alkylaromatic hydrocarbon)₂Mo, e.g. (EtBz)₂The vapor of Mo contacts under vapor deposition conditions to deposit a molybdenum material onto the substrate surface. In a particular embodiment, the deposited molybdenum material is molybdenum carbide deposited as a seed layer onto which a subsequent layer of bulk (elemental) molybdenum is coated. Use (EtBz)₂A Mo precursor deposited molybdenum carbide seed layer may be applied at a relatively low temperature (e.g., less than 300 degrees celsius, or less than 250 degrees celsius or 270 degrees celsius), wherein the molybdenum carbide seed layer has good conformality when applied to a three-dimensional structure. According to example structures and methods, molybdenum carbide may be applied to a titanium nitride surface of a three-dimensional substrate as a seed layer that provides protection to the titanium nitride material in the form of etch resistance during subsequent steps of depositing elemental molybdenum by using halide precursors. Use (EtBz)₂Mo precursor coated molybdenum carbide seed layer in a subsequent (next) step of depositing elemental molybdenumRelatively low or reduced temperatures are also allowed during, which results in improved conformal filling of complex structures, such as high aspect ratio three-dimensional structures or openings, such as vias or interconnects. For example, the substrate temperature during subsequent steps of depositing metallic molybdenum may be at least 50 degrees celsius, lower than the temperature required to deposit metallic molybdenum onto a substrate that does not include a molybdenum carbide seed layer.

According to one example method for producing a conformal molybdenum coating on a three-dimensional substrate, wherein the substrate comprises a titanium nitride surface, by using (EtBz)₂The Mo precursor deposits a molybdenum carbide seed layer onto the titanium nitride surface. In the following steps, by using any desired or suitable precursor (e.g. MoOCl)₄、MoCl₅Or MoF₆) Bulk (elemental) molybdenum is applied to the seed layer. The step of depositing the seed layer may be performed at a deposition temperature (i.e., substrate temperature) of less than 300 degrees celsius, or less than 250 degrees celsius, or 270 degrees celsius. The step of depositing bulk (elemental) molybdenum may be performed at a deposition temperature (i.e., substrate temperature) of less than 500 degrees celsius or less than 450 degrees celsius, although higher temperatures may be used if desired. The seed layer and the bulk (elemental) molybdenum layer exhibit good uniformity and conformality even when applied to highly three-dimensional surfaces, such as high aspect ratio surfaces.

As used herein, a "vapor deposition" process refers to any type of vapor deposition technique, such as CVD or ALD. In various embodiments, CVD may take the form of conventional (i.e., continuous flow) CVD, liquid injection CVD, or light assisted CVD. CVD may also take the form of pulsed techniques, i.e., pulsed CVD. In other embodiments, ALD may take the form of conventional (e.g., pulsed implantation) ALD, dedicated ALD, liquid implantation ALD, photo-assisted ALD, or plasma-assisted ALD.

In one aspect, the present invention relates to a method of forming a molybdenum-containing material on a substrate. The method comprises contacting a substrate with a bis (alkylaromatic) molybdenum (i.e., (alkylaromatic) hydrocarbon) under vapor deposition conditions₂Mo) vapor contact to deposit a molybdenum-containing material on the substrate.

Drawings

FIG. 1 illustrates a sample from MoOCl₄Molybdenum in the toolThere is a comparison of deposition rates on substrates of various surface compositions, including one surface of molybdenum carbide as described.

Figure 2 illustrates the deposition rate of molybdenum (from molybdenum bis (ethylbenzene)) at various temperature and pressure conditions during vapor deposition.

Detailed Description

The following description relates to vapor deposition methods suitable for depositing molybdenum in various forms onto a substrate by using a bis (alkylaromatic) molybdenum compound as a molybdenum precursor. Bis (alkylaromatic) molybdenum compounds (complexes) also referred to herein as (alkylaromatics)₂A Mo compound. One example of a species of such compounds that find use as precursors is molybdenum bis (ethylbenzene) (i.e., (EtBz)₂Mo). The precursors may be used in a vapor deposition (e.g., chemical vapor deposition) process to deposit molybdenum onto a substrate in any form, for example, as a compound or mixture containing molybdenum, for example, in the form of a molybdenum carbide seed layer; as elemental molybdenum in the form of a conductive structure; or as another deposited material containing molybdenum.

Chemical Vapor Deposition (CVD) is generally a chemical process in which a chemical material (derived from a "precursor") is introduced as a vapor to a substrate, optionally in combination with one or more other materials (e.g., co-reactants), under conditions that cause the vapor component to form a thin film of the material on the substrate surface.

If necessary or desired, a co-reactant, such as a reducing gas (referred to herein as a "reactant gas"), e.g., hydrogen, is introduced into the deposition chamber along with the precursor to facilitate the deposition of molybdenum in the desired form. The amount (i.e., flow rate) of the reactant gas provided to the deposition chamber can be as desired and can be effective to produce the desired form of molybdenum material deposited at the substrate surface, with the flow rate of a particular deposition process being selected in combination with other parameters of the deposition process, such as the flow rate of the precursor, the substrate temperature, and the chamber pressure.

According to the present description, a molybdenum precursor, along with optional reaction gases, may be placed in a deposition chamber containing a substrate to effect vapor deposition of molybdenum on the substrate. The conditions of the deposition chamber will be such that molybdenum from the precursor is deposited in the desired form and amountTo the substrate. For example, hydrogen and a molybdenum precursor as the reactant gases may be combined (e.g., reacted) in a manner such that molybdenum derived from the molybdenum precursor is deposited onto the substrate surface. In certain example methods, the molybdenum precursor may be formed by causing molybdenum carbide (i.e., with Mo)₂Molybdenum and carbon of crystallographic structure of C or MoC) are deposited in combination with a hydrogen reaction gas. In other example methods, the molybdenum precursor may be combined with the hydrogen reactant gas by a reaction that causes the deposition of elemental (metallic) molybdenum (i.e., molybdenum having the crystal structure of Mo).

Typically, the precursor may be carried to the deposition chamber as a vapor by using a carrier gas, which may be an inert gas such as helium, argon, nitrogen, neon, xenon, krypton, or combinations thereof. The carrier gas may be passed through a closed container (e.g., a closed container or "ampoule") containing a quantity of the precursor, e.g., in liquid form. The precursor vapor is carried by the carrier gas as it passes through the vessel, and a combination ("carrier gas-precursor mixture") may be provided to the deposition chamber.

The substrate on which the molybdenum is deposited as described in the process may be any substrate having a three-dimensional or two-dimensional surface, such as a two-dimensional or three-dimensional microelectronic or semiconductor device. According to certain currently applicable methods, the example methods as described may be particularly useful for coating molybdenum onto a three-dimensional substrate surface, including coating the substrate surface, or filling high aspect ratio three-dimensional openings. In an example method, molybdenum may be deposited onto a three-dimensional substrate as an electrically conductive seed layer of molybdenum carbide. Elemental (metallic) molybdenum, which may be derived from any precursor, preferably from a molybdenum halide or molybdenum oxyhalide precursor, may then be deposited onto the seed layer as elemental (metallic) molybdenum in the form of a conductive structure.

The precursor compounds described herein, bis (alkylaromatic) molybdenum compounds (or "complexes") (also referred to herein as (alkylaromatics))₂Mo) is also known as bis (η)⁶Arene) molybdenum complexes containing one group of compounds having an aryl group (e.g., benzene) on the complexExamples of these complexes can be synthesized by known methods, including reacting bis (η)⁶Arene ligand metathesis of benzene) molybdenum and other techniques see synthesis of bis (η) by arene metathesis⁶Molybdenum alkyl benzenes (Synthesis of Bis (η)⁶Alkylbenzzene) molybdenum by Arene metals, Victor s. asirvatham and Michael t. ashby, organometallic (Organometallics), 2001,20(8), page 1687 and 8, DOI:10.1021/om001010b, published: 3/15/2001.

These precursor compounds can be represented as having a structure comprising: a first substituted aryl group (e.g., an alkylbenzene) bonded to the molybdenum atom on a first side of the molybdenum atom and a second substituted aryl group (e.g., an alkylbenzene) bonded to the molybdenum atom on a second side of the same molybdenum atom. The compound or complex comprises a single molybdenum atom surrounding two alkyl-substituted aromatic hydrocarbon compounds on opposite sides. Compounds having one molybdenum atom located between two substituted aromatic hydrocarbon compounds are sometimes referred to as "sandwich" structures:

aromatic hydrocarbons (R) -Mo-aromatic hydrocarbons (R)

Each of the aromatic hydrocarbon compounds may be substituted with the same or different alkyl groups R. For example, each alkyl (R) may independently be methyl, ethyl, propyl, butyl, and the like, and may be branched or straight-chain. An example precursor is molybdenum bis (ethylbenzene) (i.e., (EtBz)₂Mo)：

Such compounds are commercially available in amounts and in forms (i.e., with purity) suitable for use as precursors as described.

In certain presently preferred example methods, the precursor may be deposited onto a substrate to form a seed layer of molybdenum carbide. The seed layer is a layer that contains molybdenum (e.g., molybdenum carbide) and is effective to facilitate the subsequent deposition of a bulk metallic conductive molybdenum layer on the substrate. The seed layer should be continuous over the entire surface of the substrate onto which the bulk molybdenum material (e.g., elemental (metallic) molybdenum) is to be deposited, and should allow subsequent steps of bulk molybdenum deposition to cover or fill the entire surface of the substrate, preferably allowing nucleation and coverage at lower deposition temperatures or at a more preferred quality as compared to the deposition of bulk molybdenum on an underlying substrate in the absence of a seed layer.

Preferably, the seed layer may have a thickness of 5 to 100 angstroms, such as 5 or 6 angstroms to 30, 40, or 50 angstroms.

Preferred molybdenum carbide seed layers may comprise, consist of, or consist essentially of: molybdenum and carbon in atomic ratios ranging from 1:99 to 60:40, such as 4:96 to 40:60 (carbon: molybdenum). A seed layer consisting essentially of carbon and molybdenum refers to a seed layer that contains no more than 1 percent (atomic), such as no more than 0.5, 0.1, or 0.01 percent (atomic), of any material other than carbon and molybdenum. In contrast to metallic molybdenum, the molybdenum carbide seed layer will contain a substantial amount of Mo₂C. Molybdenum and carbon in the form of MoC or both.

The substrate on which the molybdenum carbide seed layer is deposited may be any substrate, such as, for example, as described herein, including a three-dimensional substrate having a titanium nitride surface, as one particular example.

The method as described may be performed in the following deposition chambers: substantially only containing gaseous precursors, optional carrier gases, additional inert gases and one or more reactive gases during use, for example, the deposition chamber interior may be supplied with and contain an atmosphere comprising, consisting of or consisting essentially of: a gaseous precursor, optionally a carrier gas and a reaction gas. For purposes of the present invention, a deposition chamber or associated gas stream or combination of gas streams consisting essentially of a specified combination of gaseous materials (e.g., precursor vapors, optional carrier gases, and reactant gases) is considered to contain the specified combination of gaseous materials and no more than an insignificant amount of any other gaseous materials, such as no more than 5, 2, 1, 0.5, 0.1, 0.05 percent (by mass) of any other gaseous materials.

The amount of gaseous precursor (also referred to as precursor vapor) and the amount of reactant gas supplied to the deposition chamber can be amounts that would each be suitable for depositing a desired amount of molybdenum and a molybdenum composition, such as in the form of molybdenum carbide, onto a substrate surface. For respective flow rates of the two gases, the amounts and relative amounts of the two gases may be selected based on factors including: the desired form and composition of the deposited seed layer, the substrate properties (e.g., shape), the desired deposition rate, the substrate temperature, the size (volume) of the deposition chamber, and the internal pressure of the deposition chamber.

According to non-limiting examples of certain methods that have been identified as being useful, the flow rate of the molybdenum precursor may be in the range of 2 to 20 micromoles per minute, based on a deposition chamber having a volume in the range of 2,000 to 20,000 cubic centimeters, and operating at an internal pressure in the range of 10 to 50 torr. Consistent with these values and other parameters, precursor vapors may be included in the carrier gas as described at any suitable or desired concentration, such as in the range of 80 to 25,000 parts per million (ppm).

According to non-limiting examples of certain methods that have been identified as being suitable, the flow rate of the reactant gas, such as hydrogen, may be in the range of 8,000 to 25,000 micromoles per minute, based on a deposition chamber having a volume in the range of 2,000 to 20,000 cubic centimeters, and operating at an internal pressure in the range of 10 to 50 torr.

The internal pressure of the deposition chamber may be an internal pressure effective for molybdenum deposition as a seed layer. Typically, deposition chambers used for chemical vapor deposition operate at pressures below ambient, e.g., below or well below 760 torr. Suitable or preferred methods of the present description for depositing a molybdenum carbide seed layer may be carried out at a deposition chamber pressure substantially below atmospheric pressure, for example below about 200 torr, for example not exceeding 50, 80 or 100 torr, for example at a pressure in the range of 5, 10 or 15 up to 20, 30, 40 or 50 torr.

During deposition, the substrate may be maintained at any temperature effective to deposit molybdenum carbide as a seed layer onto the substrate. According to a particular example method, molybdenum may be deposited onto a substrate as a molybdenum carbide seed layer by using a desired or advantageous low deposition temperature. Examples of suitable or preferred substrate temperatures during the step of depositing the molybdenum carbide seed layer may be in the range 150 ℃ to 400 ℃, or in the range 200 ℃ to 300 ℃, preferably not exceeding a temperature of 250 ℃ or 270 ℃.

Applicants have determined that the presence of a molybdenum carbide seed layer deposited using a bis (alkylaromatic) molybdenum precursor, such as bis (ethylbenzene) molybdenum, allows for effective or advantageous further processing of the substrate during the step of depositing elemental molybdenum onto the seed layer. In particular methods, the step of depositing elemental molybdenum onto a seed layer deposited using a bis (alkylaromatic) molybdenum precursor, such as bis (ethylbenzene) molybdenum, may be performed at a low temperature that is desirable or advantageous. Thus, the deposited layer of elemental molybdenum may have a desired or advantageous conformality when deposited onto a three-dimensional substrate surface, as well as other desired functional characteristics of the elemental molybdenum structure, including low resistivity and good uniformity.

Thus, according to the use as described, containing molybdenum bis (ethylbenzene) (e.g., (EtBz)₂Mo) may be deposited onto a substrate after a seed layer is deposited onto the substrate, elemental molybdenum may be deposited onto the seed layer. The term elemental molybdenum refers to molybdenum having a metallic structure; elemental (metallic) molybdenum is, for example, electrically conductive at no more than 5, 3, 2, or 1 atomic percent but may contain non-molybdenum, such as carbon.

Can be prepared by using any molybdenum precursor, such as a bis (ethylaromatic) molybdenum precursor (e.g., (EtBz)₂Mo), or another molybdenum precursor found suitable for depositing molybdenum. Examples of other precursors include molybdenum halides and molybdenum oxyhalides precursors, such as molybdenum pentachloride (MoCl)₅) Molybdenum tetrachloride (MoOCl)₄) And molybdenum hexafluoride (MoF)₆). Halide and oxyhalide precursors have been shown to be particularly useful for depositing very high purity metallic molybdenum films with very low resistivity. However, nucleation of Mo metal films on TiN or other desired substrate surfaces may be limited. Thus, the seed layer as described may serve as an effective means to allow improved deposition of elemental molybdenum by using molybdenum halide or molybdenum oxyhalide precursors.

The elemental molybdenum deposited may be in metallic form and may have a high or very high purity, for example at least 95, 98, 99, 99.5, 99.9, or 99.99 percent (atomic) molybdenum or higher. A certain amount of non-molybdenum material (i.e., typical impurities in the deposited elemental molybdenum layer) may be preferably less than 5, 2, 1, a,0.5, 0.1 or 0.01 percent (atom.) specific impurities such as hydrogen, chlorine, oxygen, nitrogen carbon and fluorine may preferably be present at less than l × 10²⁰Deposited molybdenum per cubic centimeter (for hydrogen and chlorine), e.g. less than l × 10²¹The content of deposited molybdenum (for oxygen and carbon) per cubic centimeter is present.

Example methods may be achieved by using molybdenum halide or molybdenum oxyhalide precursors, such as molybdenum pentachloride (MoCl)₅) Molybdenum tetrachloride (MoOCl)₄) And molybdenum hexafluoride (MoF)₆) Elemental (metallic) molybdenum is deposited onto a molybdenum carbide seed layer coated with a bis (alkylaromatic) molybdenum precursor as described. Elemental (metallic) molybdenum may be coated by using a molybdenum halide or molybdenum oxyhalide precursor at a deposition temperature (i.e., substrate temperature) of less than 800 degrees celsius, 700 degrees celsius, or 500 degrees celsius, such as less than 450 degrees celsius, or less than 400 degrees celsius.

The deposited elemental molybdenum layer may have a low resistivity, for example a resistivity of no more than 20 μ Ω -cm or no more than 15 μ Ω -cm, wherein the thickness of the molybdenum film is 40 nanometers.

The deposited elemental molybdenum layer may have any desired thickness, such as a thickness in the range of 30 to 500 angstroms or 40 to 400 angstroms.

In various example embodiments of the described methods, molybdenum is deposited as a seed layer onto a three-dimensional (e.g., high aspect ratio) surface of a titanium nitride-containing substrate by contacting the substrate surface with bis (ethylbenzene) molybdenum in the presence of a carrier gas and hydrogen as a reaction gas under conditions such that the molybdenum is deposited as a molybdenum carbide barrier layer. The deposition temperature during seed layer deposition (i.e., the substrate temperature during deposition) may be less than about 300 degrees celsius, 270 degrees celsius, or 250 degrees celsius.

In the following step, by using, for example, MoOCl₄、MoOCl₅Or MoF₆The deposition process of (a) deposits molybdenum onto the substrate surface over the seed layer. Advantageously, the step of depositing elemental molybdenum onto a seed layer derived from bis (ethylbenzene) molybdenum may be performed at advantageously low process (substrate) temperatures and effective deposition rates, with desirable or advantageous results (e.g., conformality of the elemental molybdenum).

For example, fig. 1 shows a comparison of deposition rates for steps of elemental molybdenum deposition onto three substrates, one substrate with a TiN surface without a nucleation layer, one substrate with a TiN surface using B₂H₆The precursor was deposited onto the titanium nitride as the boron (B) surface of the nucleation layer, and one substrate had a molybdenum carbide surface as the seed layer deposited over the titanium nitride by using bis (ethylbenzene) molybdenum as the precursor. Substrates comprising a molybdenum carbide seed layer deposited by using a bis (ethylbenzene) molybdenum precursor allow for an effective deposition rate of elemental molybdenum at relatively lower temperatures compared to substrates having TiN surfaces, and compared to substrates having boron surfaces as the nucleation layer.

Figure 2 shows an example of a process for depositing molybdenum carbide as a seed layer onto a substrate having a titanium nitride surface under various pressure and temperature conditions resulting in a range of deposition rates. Pressures between 10-30 torr and temperatures between 200 and 300 degrees celsius have been shown to be effective, with the combination of 30 torr and 200 degrees celsius being particularly useful for conformal molybdenum carbide seed layer deposition. Films deposited at lower temperatures have particularly good conformality. Films deposited at higher temperatures do not exhibit the same favorable conformality but can still be used as seed layers on less complex structures that do not cover the entire surface with difficulty.

In general, as described herein, bis (alkylaromatic) molybdenum compounds (e.g., (EtBz) are used₂Mo) may be deposited onto any desired substrate surface, such as the surface of a semiconductor or microelectronic device substrate, and may be adapted to perform any useful function as part of or facilitate handling of the device. Examples of functions of molybdenum deposited using the precursors as described include: as a seed or "seed" layer, as a barrier layer, or as a conductive layer (e.g., as an interconnect or "via"), among others. The deposited molybdenum may have characteristics such as composition and thickness effective to perform the desired function.

Examples of substrates and surfaces onto which molybdenum in various forms is deposited using precursors as described include any two-dimensional or three-dimensional structure, with specific examples including microelectronic device substrates such as DRAM devices, 3D NAND devices, or tri-devicesAnother apparatus having a dimensional surface with a high aspect ratio. In a particular example, molybdenum may be deposited on a three-dimensional surface (e.g., coated with titanium nitride) by using a precursor as described herein as a seed layer, followed by deposition of elemental molybdenum on the seed layer using any precursor. The substrate may comprise a high aspect ratio opening, such as a via, wherein a molybdenum carbide seed layer is first applied, followed by filling the opening with elemental molybdenum. For example, the opening may have an aspect ratio of longitudinal to lateral dimensions in a range of 2:1 to 200:1, such as 5:1 to 100:1 or 20:1 to 30: 1. Alternatively, the surface of the 3D NAND device substrate may comprise vertical walls coated with titanium nitride separated by slots, the walls comprising horizontally extending ribs and recesses, and the method may comprise forming a uniform and conformal layer (or "film") of a molybdenum carbide seed layer over the titanium nitride surface of the ribs and recesses, followed by deposition of elemental molybdenum over the seed layer. By way of specific example methods, for example, MoOCl may be used₄、MoOCl₅Or MoF₆The precursor of (a) deposits elemental molybdenum to provide an elemental molybdenum layer with good, useful, or favorable conformality.

According to certain applicable or presently preferred embodiments of the method as described, for depositing molybdenum carbide as a seed layer of a bis (alkylaromatic) molybdenum precursor onto a substrate surface, applicable (non-limiting) process parameters include the following (depending on overall process characteristics, the specified values are referred to as non-limiting since the method as generally described herein can be used when operating at these parameter values outside of the specified range):

temperature of molybdenum precursor vapor delivered into the deposition chamber: 100 to 140 degrees centigrade;

substrate temperature: below 300 degrees celsius, such as 200 degrees celsius to 250 degrees celsius or 270 degrees celsius;

deposition chamber pressure during deposition step: 10 to 50 torr, e.g., 10 to 20 torr;

flow rate of precursor-carrier gas mixture: 20 to 100sccm (standard cubic centimeters per minute);

flow rate of reaction gas (e.g., hydrogen gas): 100 to 1,000 sccm.

In these casesIn an exemplary method, after depositing the seed layer, for example, MoOCl may be used₄、MoOCl₅Or MoF₆The precursor of (a) deposits elemental molybdenum onto the seed layer. Examples of applicable (non-limiting) process parameters include the following (specified values are referred to as non-limiting since the methods as generally described herein can be used when operating with these parameter values outside of the specified ranges, depending on the overall process characteristics):

temperature of molybdenum precursor delivered into deposition chamber: 30 to 100 ℃;

platform (substrate) temperature: 300 to 800 ℃;

deposition chamber pressure during deposition step: 10 to 100 torr, e.g., 20 to 80 torr;

flow rate of precursor-carrier gas mixture: 20 to 1000 sccm;

flow rate of reaction gas (e.g., hydrogen gas): 500 to 5,000 sccm.