Molybdenum precursor compound

Abstract

The present invention provides a specific molybdenum-containing compound that is considered useful for vapor-depositing a molybdenum-containing film on the surface of various microelectronic device substrates. In one aspect, the present invention provides a method for depositing a molybdenum-containing film on a microelectronic device substrate, comprising exposing the substrate to a compound of formula (I) as described herein under vapor deposition conditions in a reaction zone.

Description

Technology Field

[0001] Claim of priority

[0002] The present invention claims priority to U.S. Provisional Patent Application No. 63 / 277,829, filed on November 10, 2021. The priority document is incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a specific molybdenum compound useful as a precursor for vapor deposition of a molybdenum-containing film on a microelectronic device substrate. Background Technology

[0005] Due to their very high melting point, low coefficient of thermal expansion, low resistivity, and high thermal conductivity, Group VI metals such as molybdenum, chromium, and tungsten are increasingly being used in the manufacture of semiconductor devices, including in diffusion barriers, electrodes, photomasks, power electronic substrates, low-resistivity gates, flat-panel displays, and interconnects.

[0006] This utility has motivated efforts to achieve the deposition of molybdenum, chromium, and tungsten films for these applications, characterized by high deposition rates and high conformality of the deposited films, to accommodate efficient high-volume manufacturing operations. This has also enabled efforts to develop improved molybdenum and tungsten source reagents useful for vapor deposition operations, as well as improved process parameters utilizing these reagents.

[0007] In the Atomic Layer Deposition (ALD) method, reactant and precursor molecules are introduced into the reaction zone via alternating pulses to create the desired chemical composition of the layer. These precursors are delivered to the wafer in gaseous form. For precursors that are gaseous at standard temperatures and pressures, the process is well-established. The precursor gas flows directly into the deposition chamber. The trend toward new interconnect materials requires a broader portfolio of precursors, many of which are liquid or solid at room temperature. These ALD precursors must possess sufficient volatility, thermal stability, and reactivity with the substrate and film being deposited. Whether they are liquid or solid, the vapor pressure of the precursor determines the process conditions.

[0008] Most liquid precursors are delivered at room temperature and vaporized by lowering the pressure. Generally, liquids are easier to purify, handle, and deliver than solid precursors. Therefore, many Integrated Device Manufacturers (IDMs) prefer liquid supply systems.

[0009] Solids are more difficult because they require heating the material and the gas lines delivering it. Ideally, the precursor should be non-flammable, non-corrosive, and non-toxic, and production should be simple and inexpensive.

[0010] summation

[0011] In summary, the present invention provides a specific molybdenum-containing compound that is considered useful for vapor-depositing a molybdenum-containing film on the surface of various microelectronic device substrates. In one aspect, the present invention provides a method for depositing a molybdenum-containing film on a microelectronic device substrate, comprising exposing the substrate to a compound of formula (I) under vapor deposition conditions in a reaction zone to form a molybdenum-containing film on the substrate:

[0012]

[0013] Here, each R is independently selected from (i) C1-C4 alkyl or (ii) C1-C4 alkyl substituted with one or more halogen atoms. Brief explanation of the drawing

[0014] Figure 1 is a thermogravimetric analysis of the compound molybdenum (II) acetate dimer showing that 50% of the mass was evaporated by 310°C. Figure 2 is a thermogravimetric analysis of the common precursor HfCl4 showing that 50% of the mass is evaporated by 290°C; thus, molybdenum (II) acetate dimer can be transferred in this way by vapor deposition techniques such as ALD at similar temperatures. Specific details for implementing the invention

[0015] details

[0016] As used in this specification and the appended claims, the singular form includes plural objects unless the content clearly indicates otherwise. As used in this specification and the appended claims, the term “or” is generally used to include “and / or” unless the content clearly indicates otherwise.

[0017] The term "approximately" generally refers to a range of numbers considered equivalent to a quoted value (e.g., having the same function or result). In many cases, the term "approximately" may include numbers rounded to the nearest significant figure.

[0018] A number range expressed using endpoints includes all numbers contained within that range (e.g., 1 through 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0019] In a first aspect, the present invention provides a method for depositing a molybdenum-containing film on a microelectronic device substrate, comprising exposing the substrate to a compound of formula (I) under vapor deposition conditions in a reaction zone to form a molybdenum-containing film on the substrate:

[0020]

[0021] Here, each R is independently selected from (i) C1-C4 alkyl or (ii) C1-C4 alkyl substituted with one or more halogen atoms.

[0022] In one embodiment, each R is selected from methyl, tert-butyl, and trifluoromethyl.

[0023] The compound of formula (I) as shown above exists as a dimer of molybdenum-containing alkanoate. In other words, the compound of formula (I) has the following empirical formula:

[0024]

[0025] Here, R is as defined above.

[0026] Many of the compounds of formula (I) are known and can be prepared by treating molybdenum hexacarbonyl (Mo(CO)6) with acetic acid (i.e., when R is methyl). Similarly, other carboxylic acids may be used for the corresponding R group of formula (I). (e.g., literature ( Rhenium and Molybdenum Compounds Containing Quadruple Bonds , Alicia B. Brignole, F. A. Cotton, Z. Dori, Z. Dori, Z. Dori, G. Wilkinson; Book Editor(s):FA Cotton; First published: 01 January 1972; https: / / doi.org / 10.1002 / 9780470132449.ch15)(See also). Also, when R is methyl, the compound molybdenum (II) acetate dimer can be obtained commercially from Sigma Aldrich (CAS No. 14221-06-8).

[0027] Compounds of chemical formula (I) are considered useful for the chemical deposition of molybdenum-containing films. In this regard, the term "molybdenum-containing" film refers to such a film composed of one or more of molybdenum metal, molybdenum oxide, molybdenum carbide, and molybdenum nitride.

[0028] Chemical vapor deposition techniques include methods referred to as chemical vapor deposition (CVD) and atomic layer deposition (ALD) techniques, which also include a number of derivative versions thereof, such as UV laser photo-dissociation CVD, plasma-assisted CVD, pulsed CVD, and plasma-assisted ALD. In depositing high-purity metals on 2- or 3-dimensional microelectronic device substrates, these types of vapor deposition methods may be desirable because they can provide a high level of purity of the deposited metal and good conformal step coverage for often very non-planar microelectronic device geometries.

[0029] In one embodiment, a molybdenum-containing film or layer deposited on a substrate surface can be formed, for example, by chemical vapor deposition, pulsed chemical vapor deposition (CVD) or atomic layer deposition (ALD), and thus can be formed directly from vapor derived from a compound of formula (I).

[0030] In one embodiment, the compound(s) of formula (I) are introduced into a reaction zone containing a microelectronic device substrate along with a reducing gas. The conditions of the reaction zone are selected so that the molybdenum contained in the precursor of formula (I) is deposited on the microelectronic device substrate as molybdenum metal. In one embodiment, the precursor and the reducing gas are introduced into the reaction zone continuously. In another embodiment, an oxidizing gas, such as oxygen, ozone, or a combination of water and hydrogen, may be introduced into the reaction zone to improve the composition of the deposited metal layer. Thus, the oxidizing gas is introduced in an amount and manner such that the oxidizing gas reduces the amount of carbon deposited on the finished molybdenum layer. In one embodiment, such oxidizing gas is introduced intermittently, in pulses. Further details regarding this technique can be found in U.S. Patent Publication No. 2020 / 0115798, incorporated herein by reference.

[0031] Accordingly, in one embodiment, the present invention provides a method for depositing a molybdenum-containing film on a microelectronic device substrate, comprising introducing a precursor of formula (I) into a reaction zone containing the microelectronic device substrate while introducing a reducing gas into the reaction zone. In another embodiment, the method further comprises the step of intermittently introducing pulses of an oxidizing gas into the reaction zone.

[0032] In another embodiment, a molybdenum precursor of formula (I) is introduced into a reaction zone containing a microelectronic device substrate, followed by a pulsed introduction of an oxidizing gas (e.g., H2O vapor), followed by a pulsed introduction of a reducing gas (e.g., H2). In this way, a molybdenum metal film can be deposited on the surface of the microelectronic device substrate. Accordingly, in a further embodiment, the present invention provides a method for depositing a molybdenum-containing film on a microelectronic device substrate, comprising (i) introducing a precursor of formula (I) into a reaction zone containing a microelectronic device substrate, intermittently (ii) exposing the substrate to an oxidizing gas; and intermittently (iii) exposing the substrate to a reducing gas. In certain embodiments, the precursor, the oxidizing gas, and the reducing gas are introduced in pulses in an atomic layer deposition regime.

[0033] In a specific embodiment of the present invention, the oxidizing gas consists of a gas selected from H2O vapor, H2O2, O3, and N2O. In a specific embodiment of the present invention, the reducing gas consists of a gas selected from H2, hydrazine (N2H4), methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, and NH3. Given the oxidation potentials of H2O2 and O3, it will be understood that these gases should not be used with hydrazine (N2H4), methylhydrazine, t-butylhydrazine, 1,1-dimethylhydrazine, or 1,2-dimethylhydrazine, or if used sequentially, any of these gases remaining from these steps must be purged from the reactor before exposing the substrate to other reactants. Further details regarding this technique can be found in U.S. Patent Publication No. 2021 / 062331, incorporated herein by reference.

[0034] In certain cases, nitrogen-containing reducing gases such as ammonia (NH3) and hydrazine (N2H4); C1-C4 alkyl hydrazines, such as methyl hydrazine, t-butyl hydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine, may be useful, but under some conditions, a molybdenum-containing nitride film will be formed instead of a pure metal film. Likewise, in certain embodiments, carbon-containing reducing gases such as carbon monoxide, alkanes, alkenes, and alkynes may be useful, but under some conditions, a molybdenum carbide film will be formed instead of a pure metal film. In one embodiment, the reducing gas is hydrogen.

[0035] The method disclosed herein may involve one or more purge gases, as well as carrier gases, as an optional step between the introduction of the metal precursor and the reducing gas and / or oxidizing gas. The purge or carrier gas, used to remove unconsumed reactants and / or reaction by-products, or to act as a diluent and carrier for the metal precursor and the reducing or oxidizing gas, is an inert gas that does not react with the precursor. Exemplary gases include, but are not limited to, argon, nitrogen, helium, neon, and mixtures thereof. In certain embodiments, a purge gas such as Ar is supplied to the reactor at a flow rate ranging from about 10 to about 10,000 sccm for about 0.1 to 1,000 seconds to purge any unreacted material and any by-products that may remain in the reactor. Alternatively, such an inert gas may be utilized as a carrier gas to vary the concentration of the molybdenum precursor and / or oxidizing and / or reducing gas injected into the reaction zone as used herein. The use of the carrier gas and its flow rate will ultimately depend on the composition of the deposition tool, its operational scale, and the specific precursor utilized.

[0036] In one embodiment, a reducing gas may be utilized with a precursor of formula (I) to carry out the formation of an elemental molybdenum-containing film. Alternatively, when using a precursor as described herein as a means of depositing a metal oxide thin film, e.g., MoO2, an oxidizing gas (i.e., a co-reactant) such as oxygen may be added to the process.

[0037] In various embodiments, vapor deposition conditions include an inert atmosphere except for the optional presence of such reducing and / or oxidizing gases. In certain embodiments, the precursor vapor may be deposited in the substantial absence of other metal vapors.

[0038] In certain embodiments, the molybdenum-containing layer deposited on the substrate surface may be formed without the prior formation of a nucleation layer, for example, by chemical vapor deposition (CVD), pulsed chemical vapor deposition, atomic layer deposition (ALD), or other (thermal) vapor deposition techniques. Each precursor vapor contact step may be performed alternately and repeatedly for a desired number of cycles to form the desired thickness of the molybdenum-containing film. In various embodiments, contact between the substrate layer (e.g., titanium nitride) and the vapor of the compound of formula (I) is performed at a temperature in the range of 200°C to 750°C and at a pressure of about 0.5 to about 500 Torr for such vapor deposition. The pulsed introduction of the compound(s) of formula (I), the reducing gas, and the oxidizing gas may be in a duration range of about 0.2 seconds to about 60 seconds in certain embodiments.

[0039] As mentioned above, the molybdenum metal-containing material can be deposited directly onto a substrate to form bulk deposits of molybdenum metal, oxide, carbide, or nitride. When depositing an elemental molybdenum film and using H2 as a reducing gas, the concentration of H2 is important for the formation of the molybdenum metal versus oxide, because H2 greater than 4 molar equivalents or in excess is required for metal formation. (4) H2 less than molar equivalents will cause varying amounts of molybdenum metal oxides to form, and thus will require additional exposure to H2 to reduce the molybdenum oxides thus formed.

[0040] According to the present disclosure, the process chemistry for depositing such molybdenum-containing materials may include the deposition of elemental molybdenum, Mo(O), by the reaction Mo2(O2CCH3)4+2H2→2Mo+4HOCCH3. Intermediate reactions may exist and are well known in the relevant art.

[0041] A molybdenum-containing material deposited according to the method of the present invention may be characterized by any suitable evaluation metrics and parameters, such as the deposition rate of the molybdenum-containing material, the film resistivity of the deposited molybdenum-containing material, the film morphology of the deposited molybdenum-containing material, the film stress of the deposited molybdenum-containing material, the step coverage of the material, the film composition and purity, and a process window or process envelope of suitable process conditions. Any suitable evaluation metrics and parameters may be used to characterize the deposited material and associate it with specific process conditions to enable mass production of corresponding semiconductor products and flat panel displays. Advantageously, the method of the present invention is believed to be capable of depositing a film of high-purity molybdenum metal on a microelectronic device substrate.

[0042] The substrate used in the deposition method of the present invention may be of any suitable type and may include, for example, a microelectronic device substrate, for example, a silicon substrate, a silicon dioxide substrate, or other silicon-based substrate. In various embodiments, the substrate may include one or more metallic or dielectric substrates, for example, Co, Cu, Al, W, WN, WC, TiN, Mo, MoC, SiO2, W, SiN, WCN, Al2O3, AlN, ZrO2, HfO2, SiO2, lanthanum oxide (La2O3), tantalum nitride (TaN), niobium nitride, ruthenium oxide (RuO2), iridium oxide (IrO2), niobium oxide (Nb2O3), and yttrium oxide (Y2O3).

[0043] In certain embodiments, for an oxide substrate such as silicon dioxide, or alternatively a silicon or polysilicon substrate, the substrate may be treated or manufactured to include a barrier layer, for example titanium nitride, thereon for a material subsequently deposited.

[0044] It will be understood that the method of the present invention can be performed in a number of alternative ways and under a wide variety of process conditions. Microelectronic or semiconductor devices may be of any suitable type and may include, for example, DRAM devices, 3-D NAND devices, or other devices or device-integrated structures. In various embodiments, the substrate may include vias into which a molybdenum-containing material is deposited. The device may have an aspect ratio of depth to side dimensions, for example, in the range of 10:1 to 40:1. In other embodiments, the method may be performed in the manufacture of microelectronic device products such as mobile devices, logic devices, flat-panel displays, or IC packaging components.

[0045] In the method of the present invention, the precursor compound can react with a desired microelectronic device surface or substrate in any suitable manner, for example, in a single wafer chamber, a multi-wafer chamber, or in a furnace containing multiple wafers.

[0046] As used herein, the term “microelectronic device” corresponds to a semiconductor substrate including 3D NAND structures, logic devices, DRAMs, power devices, flat panel displays, and microelectromechanical systems (MEMS) manufactured for use in microelectronic, integrated circuit, or computer chip applications. The term “microelectronic device” is not intended to be limited in any way and should be understood to include any substrate that includes n-type channel metal oxide semiconductor (nMOS) and / or p-type channel metal oxide semiconductor (pMOS) transistors and will eventually become a microelectronic device or microelectronic assembly. Additionally, the underlying substrate does not necessarily have to be silicon, but may be an insulator such as glass or sapphire, a high bandgap semiconductor such as SiC or GaN, or other materials useful for manufacturing electrical circuits. The microelectronic device comprises at least one substrate, which may be selected from, for example, silicon, SiO2, Si3N4, OSG, FSG, silicon carbide, hydrogenated silicon carbide, silicon nitride, hydrogenated silicon nitride, silicon carbonitride, hydrogenated silicon carbonitride, boronitride, anti-reflective coating, photoresist, germanium, germanium-containing, boron-containing, Ga / As, flexible substrate, porous inorganic material, metals such as copper and aluminum, and diffusion barrier layers such as but not limited to TiN, Ti(C)N, TaN, Ta(C)N, Ta, W, or WN. The film is compatible with various subsequent processing steps, such as, for example, chemical mechanical planarization (CMP) and anisotropic etching processes.

[0047] side

[0048] In a first aspect, the present invention provides a method for depositing a molybdenum-containing film on a microelectronic device substrate, comprising exposing the substrate to a compound of formula (I) under vapor deposition conditions in a reaction zone to form a molybdenum-containing film on the substrate:

[0049]

[0050] Here, each R is independently selected from (i) C1-C4 alkyl or (ii) C1-C4 alkyl substituted with one or more halogen atoms.

[0051] In a second aspect, the present invention provides a method of the first aspect in which each R is a C1-C4 alkyl.

[0052] In a third aspect, the present invention provides a method of the first aspect in which each R is methyl.

[0053] In a fourth aspect, the present invention provides a method of the first or second aspect in which each R is tert-butyl.

[0054] In a fifth aspect, the present invention provides a method of the first aspect in which each R is trifluoromethyl.

[0055] In a sixth aspect, the present invention provides a method of any one of the first to fifth aspects, wherein the vapor deposition conditions include a temperature of about 200°C to about 750°C and a pressure of about 0.5 to about 500 Torr.

[0056] In a seventh aspect, the present invention provides a method of any one of the first to sixth aspects, wherein the vapor deposition conditions include introducing a compound of formula (I) into a reaction zone containing a microelectronic device substrate while introducing a reducing gas into the reaction zone.

[0057] In an eighth aspect, the present invention provides a method of a seventh aspect in which the vapor deposition condition further comprises the step of intermittently introducing pulses of oxidizing gas into the reaction zone.

[0058] In a ninth aspect, the present invention provides a method of any one of the first to sixth aspects, wherein the vapor deposition conditions comprise (i) introducing a precursor of formula (I) into a reaction zone containing a microelectronic device substrate, intermittently (ii) exposing the substrate to an oxidizing gas; and intermittently (iii) exposing the substrate to a reducing gas.

[0059] In the 10th aspect, the present invention provides a method of the 7th or 9th aspect in which the reducing gas is composed of a gas selected from H2, hydrazine, methylhydrazine, t-butylhydrazine, 1,2-dimethylhydrazine, 1,2-dimethylhydrazine, and NH3.

[0060] In the eleventh aspect, the present invention provides a method of the eighth or ninth aspect in which the oxidizing gas is selected from H2O vapor, H2O2, O3, and N2O.

[0061] In the 12th aspect, the present invention provides a method of any one of the 1st to 11th aspects in which the substrate is selected from titanium nitride, tantalum nitride, aluminum nitride, aluminum oxide, zirconium oxide, hafnium oxide, silicon dioxide, silicon nitride, lanthanum oxide, ruthenium oxide, iridium oxide, niobium oxide, and yttrium oxide.

[0062] In a 13th aspect, the present invention provides a method of any one of the 1st to 12th aspects in which the molybdenum-containing film is molybdenum metal.

[0063] Since various exemplary embodiments of the present disclosure have been described in this manner, those skilled in the art will readily understand that other embodiments may be made and used within the scope of the appended claims. Many advantages of the disclosure covered by this document have been presented in the foregoing description. However, it will be understood that the present disclosure is, in many respects, merely illustrative. Of course, the scope of the present disclosure is defined in the language in which the appended claims are expressed.

Claims

Claim 1 A method for depositing a molybdenum-containing film on a microelectronic device substrate under atomic layer deposition (ALD) or chemical vapor deposition (CVD) conditions, comprising exposing the substrate to a compound of formula (I) under vapor deposition conditions in a reaction zone to form a molybdenum-containing film on the substrate: Here, each R is independently selected from (i) C1-C4 alkyl or (ii) C1-C4 alkyl substituted with one or more halogen atoms. Claim 2 A method according to claim 1, wherein each R is methyl. Claim 3 The method of claim 1, wherein each R is tert-butyl. Claim 4 A method according to claim 1, wherein the vapor deposition conditions include a temperature of 200°C to 750°C and a pressure of 0.5 to 500 Torr. Claim 5 A method according to claim 1, wherein the vapor deposition condition further comprises the step of pulse-introducing an oxidizing gas into the reaction zone for a duration range of 0.2 seconds to 60 seconds. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete Claim 13 delete

Images