Method for manufacturing semiconductor substrate, method for manufacturing boron-containing film, boron-containing film forming material, and boron-containing compound

Abstract

Provided are: a method for manufacturing a semiconductor substrate, with which it is possible to form a boron-containing film that has a low dielectric constant; a method for manufacturing a boron-containing film; a boron-containing film forming material; and a boron-containing compound. This method for manufacturing a semiconductor substrate includes a step for bringing a substrate into contact with a boron-containing compound. The boron-containing compound includes at least one compound that is selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2).　(In formulae (1) and (2), X is a monovalent group having a nitrogen-containing heterocyclic ring having 1 to 20 carbon atoms, or a monovalent group represented by formula (a); R1 to R3 are each a monovalent organic group having 1 to 40 carbon atoms, or a hydrogen atom; and n is an integer of 1 to 4.) (In formula (a), R4 to R5 are each a monovalent organic group having 1 to 40 carbon atoms, or R4 to R5 are combined with each other to constitute a nitrogen-containing heterocyclic ring having 3 to 10 ring atoms together with a nitrogen atom to which these moieties are bonded; and R6 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

Description

Method for manufacturing semiconductor substrates, method for manufacturing boron-containing films, boron-containing film-forming materials, and boron-containing compounds

[0001] This invention relates to a method for manufacturing a semiconductor substrate, a method for manufacturing a boron-containing film, a boron-containing film-forming material, and a boron-containing compound.

[0002] As semiconductor devices such as ICs and LSIs become more sophisticated, miniaturization of the components used in them is required. Regarding materials used in interlayer insulating films, the development of low-dielectric materials such as boron nitride is desired in order to suppress signal delay and enable high-speed transmission in devices. As a method for forming boron nitride films, for example, a technique has been proposed in which a boron-containing gas and a nitrogen-containing gas are brought into contact on a substrate to form a boron nitride film (see Japanese Patent Publication No. 7136453).

[0003] Patent No. 7136453

[0004] The interlayer insulating film requires low dielectric properties, which can suppress signal delay in semiconductor devices and contribute to even faster transmission.

[0005] The object of the present invention is to provide a method for manufacturing a semiconductor substrate capable of forming a low dielectric constant boron-containing film, a method for manufacturing a boron-containing film, a boron-containing film forming material, and a boron-containing compound.

[0006] In one embodiment, the present invention relates to a method for manufacturing a semiconductor substrate, comprising the step of bringing a substrate into contact with a boron-containing compound (hereinafter also referred to as "[A] compound"), wherein the boron-containing compound comprises at least one selected from the group consisting of a compound represented by the following formula (1) (hereinafter also referred to as "[A1] compound") and a compound represented by the following formula (2) (hereinafter also referred to as "[A2] compound"). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４~R ５ is each independently a monovalent organic group having 1 to 40 carbon atoms or R ４ ~R ５ are combined with each other to form a nitrogen-containing heterocyclic ring having 3 to 10 ring members together with the nitrogen atom to which they are attached. R ６ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. * is a bond to the boron atom in the above formulas (1) to (2).)

[0007] In another embodiment, the present invention includes a step of bringing a substrate into contact with a boron-containing compound, and the boron-containing compound includes at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2), and relates to a method for producing a boron-containing film. (In the above formulas (1) to (2), X is each independently a monovalent group having a nitrogen-containing heterocyclic ring having 1 to 20 carbon atoms or a monovalent group represented by the following formula (a). R １ ~R ３ are each independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer of 1 to 4.) (In the above formula (a), R ４ ~R ５ are each independently a monovalent organic group having 1 to 40 carbon atoms or R ４ ~R ５ are combined with each other to form a nitrogen-containing heterocyclic ring having 3 to 10 ring members together with the nitrogen atom to which they are attached. R ６ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. * is a bond to the boron atom in the above formulas (1) to (2).)

[0008] In yet another embodiment, the present invention relates to a boron-containing film-forming material including at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2). (In the above formulas (1) to (2), X is each independently a monovalent group having a nitrogen-containing heterocyclic ring having 1 to 20 carbon atoms or a monovalent group represented by the following formula (a). R １ ~R ３Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

[0009] In yet another embodiment, the present invention relates to a boron-containing compound comprising at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing aliphatic heterocycle with 1 to 20 carbon atoms. １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4.

[0010] In this specification, "organic group" means a group containing at least one carbon atom. "Fused ring" or "fused ring structure" means a structure in which two adjacent rings share one edge (two adjacent atoms).

[0011] The semiconductor substrate manufacturing method allows for the formation of a low dielectric constant boron-containing film, enabling the efficient production of high-quality semiconductor substrates. The boron-containing film manufacturing method, the boron-containing film forming material, and the boron-containing compound enable the efficient production of a low dielectric constant boron-containing film. Therefore, these can be suitably used in the manufacture of semiconductor devices, where further miniaturization is expected in the future.

[0012] The following describes in detail the semiconductor substrate manufacturing method, boron-containing film manufacturing method, boron-containing film forming material, and boron-containing compound according to each embodiment of the present invention. Preferred combinations of embodiments are also preferred.

[0013] 《Method for Manufacturing a Semiconductor Substrate》 The method for manufacturing the semiconductor substrate includes a step of bringing the substrate into contact with compound [A]. Preferably, the method for manufacturing the semiconductor substrate includes a vaporization step of vaporizing compound [A] before the contact step. The method for manufacturing the semiconductor substrate may also include a cleaning step of cleaning the substrate after the contact step.

[0014] First, after explaining compound [A], each step of the manufacturing method for the semiconductor substrate will be explained, including the preferred step of vaporization and the optional step of cleaning.

[0015] ([A] compound) The [A] compound includes at least one selected from the group consisting of the [A1] compound and the [A2] compound. The [A1] compound and the [A2] compound are the compound represented by the following formula (1) and the compound represented by the following formula (2), respectively.

[0016] (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

[0017] A monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms represented by X is a group obtained by removing one hydrogen atom from a nitrogen-containing heterocycle with 1 to 20 carbon atoms. The above nitrogen-containing heterocycle has a ring structure in which a nitrogen atom is included as an atom constituting the ring. The number of nitrogen atoms in the above nitrogen-containing heterocycle is not particularly limited, but can be 1 to 4, preferably 1 to 3, and more preferably 1 or 2. In the above nitrogen-containing heterocycle, in addition to the nitrogen atom, heteroatoms such as oxygen atoms and sulfur atoms may be included as ring constituent atoms, or in place of these, -CO-, -CS-, -NR'-, -SO ２ -Or it may include a divalent heteroatom-containing linking group that combines these. Preferably, the nitrogen-containing heterocycle does not contain heteroatoms other than nitrogen atoms as ring constituent atoms (it contains only nitrogen atoms).

[0018] The nitrogen-containing heterocycle may be a monocyclic or polycyclic nitrogen-containing aliphatic heterocycle, a monocyclic or polycyclic nitrogen-containing aromatic heterocycle, or a combination thereof. A structure in which a nitrogen-containing aliphatic heterocycle and an aromatic ring that does not contain a nitrogen atom (for example, a fused ring structure of the two) is treated as a nitrogen-containing aromatic heterocycle. It is preferable that both the nitrogen-containing aliphatic heterocycle and the nitrogen-containing aromatic heterocycle have a monocyclic structure. The nitrogen-containing aliphatic heterocycle preferably has a 3- to 10-membered ring structure, more preferably a 4- to 8-membered ring structure, and even more preferably a 4- to 6-membered ring structure. The ring containing the nitrogen atom in the nitrogen-containing aromatic heterocycle preferably has a 5-membered ring structure or a 6-membered ring structure.

[0019] Examples of nitrogen-containing aliphatic heterocycles include structures represented by the following formula (including both monocyclic and polycyclic structures).

[0020]

[0021] Examples of the nitrogen-containing aromatic heterocycles mentioned above include structures represented by the following formula (including both monocyclic and polycyclic structures).

[0022]

[0023] The nitrogen-containing heterocycle described above may have substituents. Examples of substituents include halogen atoms such as fluorine, chlorine, bromine, and iodine; hydroxyl groups; carboxyl groups; cyano groups; nitro groups; alkyl groups, alkoxy groups, alkoxycarbonyl groups, alkoxycarbonyloxy groups, acyl groups, acyloxy groups, aryl groups, or combinations thereof; or groups in which the hydrogen atoms of these groups are substituted with halogen atoms, hydroxyl groups, carboxyl groups, cyano groups, or nitro groups; and oxo groups (=O).

[0024] In the monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, it is preferable that the nitrogen atom constituting the nitrogen-containing heterocycle is bonded to the boron atom in formulas (1) to (2). That is, in the formulas shown as specific examples of the nitrogen-containing aliphatic heterocycle and the nitrogen-containing aromatic heterocycle, it is preferable that the nitrogen atom of the group excluding the hydrogen atom bonded to the nitrogen atom is bonded to the boron atom in formulas (1) to (2).

[0025] When X is a monovalent group represented by the above formula (a), R ４ ~R ５ Examples of monovalent organic groups having 1 to 40 carbon atoms represented by this formula include monovalent hydrocarbon groups having 1 to 40 carbon atoms, groups having a divalent heteroatom-containing linking group between the carbon atoms of the hydrocarbon group, groups in which some or all of the hydrogen atoms of the hydrocarbon group are replaced with monovalent heteroatom-containing substituents, or combinations thereof.

[0026] Examples of the above-mentioned monovalent hydrocarbon groups having 1 to 40 carbon atoms include monovalent chain hydrocarbon groups having 1 to 40 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 40 carbon atoms, monovalent aromatic hydrocarbon groups having 6 to 40 carbon atoms, or combinations thereof.

[0027] Examples of monovalent chain hydrocarbon groups having 1 to 40 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl groups; alkenyl groups such as ethenyl, propenyl, and butenyl groups; and alkynyl groups such as ethynyl, propynyl, and butynyl groups.

[0028] Examples of monovalent alicyclic hydrocarbon groups having 3 to 40 carbon atoms include cycloalkyl groups such as cyclopentyl and cyclohexyl groups; cycloalkenyl groups such as cyclopropenyl, cyclopentenyl, and cyclohexenyl groups; bridged ring saturated hydrocarbon groups such as norbornyl, adamantyl, and tricyclodecyl groups; and bridged ring unsaturated hydrocarbon groups such as norbornyl and tricyclodecenyl groups.

[0029] Examples of monovalent aromatic hydrocarbon groups having 6 to 40 carbon atoms include phenyl, tolyl, naphthyl, anthracenyl, and pyrenyl groups.

[0030] Examples of heteroatoms that constitute a divalent heteroatom-containing linking group or a monovalent heteroatom-containing substituent include oxygen, nitrogen, sulfur, phosphorus, and halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0031] Examples of divalent heteroatom-containing linking groups include -CO-, -CS-, -NR'-, -O-, -S-, and -SO ２ -Or groups that combine these. R' is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.

[0032] Examples of monovalent heteroatom-containing substituents include hydroxyl groups, sulfanyl groups, cyano groups, nitro groups, and halogen atoms. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0033] R ４ ~R ５ As a nitrogen-containing heterocycle with 3 to 10 members, formed by combining these with each other and bonding them together with nitrogen atoms, the nitrogen-containing heterocycle in a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms represented by X in formulas (1) to (2) above can be suitably adopted.

[0034] In the above formula (a), R ４ ~R ５Preferably, each of these is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, a substituted or unsubstituted monovalent chain hydrocarbon group having 1 to 10 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0035] R ４ ~R ５ As a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms represented by the above formulas (1) to (2), a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms represented by X can be preferably adopted.

[0036] R ４ ~R ５ The monovalent linear hydrocarbon group having 1 to 10 carbon atoms represented by is preferably a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, more preferably a monovalent linear saturated hydrocarbon group having 1 to 5 carbon atoms, and even more preferably a methyl group or an ethyl group.

[0037] R ４ ~R ５ The monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by is preferably a monovalent aromatic hydrocarbon group having 6 to 14 carbon atoms, preferably a phenyl group, a naphthyl group, or an anthracenyl group, and more preferably a phenyl group.

[0038] R ４ ~R ５ If the molecule has substituents, the substituents that the nitrogen-containing heterocycle can have, as shown in X in formulas (1) to (2) above, can be suitably adopted.

[0039] R ６ Examples of C1-C3 alkyl groups represented by include methyl, ethyl, n-propyl, and isopropyl groups. ６ The preferred group is a hydrogen atom, a methyl group, or an ethyl group; a hydrogen atom or a methyl group is more preferred; and a hydrogen atom is even more preferred.

[0040] R １ ~R ３ As a monovalent organic group having 1 to 40 carbon atoms, R ４ ~R ５A monovalent organic group having 1 to 40 carbon atoms, represented by [the formula shown], can be suitably used.

[0041] In the above formula (1), R １ Each of these is preferably independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, a monovalent linear hydrocarbon group having 1 to 10 carbon atoms, or a hydrogen atom, and more preferably a monovalent linear hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom.

[0042] In the above formula (2), R １ Preferably, each of these is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent linear hydrocarbon group having 1 to 10 carbon atoms, and more preferably a monovalent linear hydrocarbon group having 1 to 10 carbon atoms.

[0043] R in the above formulas (1) to (2) １ As a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms represented by the above formulas (1) to (2), a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms represented by X can be preferably adopted.

[0044] R in the above formulas (1) to (2) １ The monovalent linear hydrocarbon group having 1 to 10 carbon atoms represented by is preferably a monovalent linear saturated hydrocarbon group having 1 to 10 carbon atoms, more preferably a monovalent linear saturated hydrocarbon group having 1 to 5 carbon atoms, with methyl and ethyl groups being even more preferred, and methyl groups being particularly preferred.

[0045] R １ ~R ３ If the molecule has substituents, the substituents that the nitrogen-containing heterocycle can have, as shown in X in formulas (1) to (2) above, can be suitably adopted.

[0046] In the above formula (2), R ２ ~R ３ It is preferable that it be a hydrogen atom.

[0047] In the above formula (2), n is preferably 2 or 3.

[0048] [A1] Specific examples of compounds include, for example, compounds represented by the following formula.

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] [A2] Specific examples of compounds include, for example, compounds represented by the following formula.

[0056]

[0057]

[0058]

[0059] (Method for synthesizing compound [A1]) Compound [A1] can be synthesized by known methods. Typically, it can be synthesized according to the scheme below.

[0060] (In the scheme, R １ This is equivalent to equations (1) and (2) above. Q is a halogen atom. The dashed lines represent bonds with other structures.

[0061] Borazine derivatives are produced by reacting ammonia derivatives (including hydrochloride salts) with boron halides. The target [A1] compound can be synthesized by reacting the borazine derivative with an amine having the structure corresponding to X in formula (1) above. Other structures can also be synthesized by appropriately changing the starting materials and amine structures.

[0062] (Method of synthesis of compound [A2]) Compound [A2] can be synthesized by known methods. Typically, it can be synthesized according to the scheme below. In formula (2) above, R ２ and R ３ Let's explain the case where all of them are hydrogen atoms.

[0063] (In the scheme, R １ And n are equivalent to those in formulas (1) and (2) above. Y is an amino group. The dashed lines indicate bonds with other structures.

[0064] A borazin derivative is produced by reacting tris(amino)borane with a diamine. The target [A1] compound can be synthesized by a salt exchange reaction between the borazin derivative and an amine having the structure corresponding to X in formula (1) above. Other structures can also be synthesized by appropriately changing the starting materials and amine structures.

[0065] (Vaporization step) In this step, compound [A] is vaporized before the contact step described above. Compound [A] may be a liquid or a solid at room temperature and atmospheric pressure.

[0066] The method for vaporizing compound [A] is not particularly limited and includes, for example, heating the raw material container containing compound [A], reducing the pressure inside the raw material container containing compound [A], or a combination thereof. The vaporization of compound [A] may be carried out using a vaporization chamber instead of the raw material container. The size, material, and structure of the raw material container and vaporization chamber are not particularly limited and may be determined appropriately considering the heating temperature and the degree of reduced pressure.

[0067] The heating temperature is not particularly limited. The lower limit of the heating temperature is preferably 30°C, more preferably 35°C, and even more preferably 40°C. The upper limit of the heating temperature is preferably 150°C, more preferably 100°C, and even more preferably 70°C.

[0068] The pressure used for decompression is not particularly limited.

[0069] When vaporizing compound [A], either the compound [A] itself may be vaporized, or a solution of compound [A] dissolved in an organic solvent may be vaporized. The organic solvent is not particularly limited and examples include ester solvents, ether solvents, hydrocarbon solvents, etc.

[0070] Examples of ester solvents include carbonate solvents such as diethyl carbonate, acetic acid monoester solvents such as methyl acetate and ethyl acetate, lactone solvents such as γ-butyrolactone, polyhydric alcohol partial ether carboxylate solvents such as diethylene glycol acetate monomethyl ether and propylene glycol acetate monomethyl ether, and lactate ester solvents such as methyl lactate and ethyl lactate.

[0071] Examples of ether-based solvents include linear ether solvents such as n-butyl ether, polyhydric alcohol ether solvents such as cyclic ether solvents such as tetrahydrofuran, and polyhydric alcohol partial ether solvents such as diethylene glycol monomethyl ether and propylene glycol monomethyl ether.

[0072] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-pentane, n-hexane, and cyclohexane, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene.

[0073] The vaporized [A] compound is introduced into a film deposition chamber, for example, for use in the contact process. The method of introducing the vaporized [A] compound into the film deposition chamber is not particularly limited, and examples include directly circulating the vaporized [A] compound into the film deposition chamber, or circulating the [A] compound into the film deposition chamber together with a carrier gas such as argon, nitrogen, ammonia, or helium.

[0074] (Contact Process) In this process, the substrate and the [A] compound are brought into contact. This process is preferably carried out by chemical vapor deposition (CVD) using the [A] compound alone or in combination as raw materials. The CVD method also includes atomic layer deposition (ALD) method.

[0075] (Substrate) The substrate is not particularly limited as long as it is an object on which a thin film having groups derived from a boron-containing compound can be formed on its surface. Examples of substrates include metal or metallometallic substrates such as silicon substrates, aluminum substrates, nickel substrates, chromium substrates, molybdenum substrates, tungsten substrates, copper substrates, tantalum substrates, and titanium substrates, and among these, silicon substrates are preferred. An inorganic film or an organic film may be formed on the above substrate. Examples of inorganic films include silicon nitride films, alumina films, and SiO formed by CVD. ２ Examples of films include films, TiON films, SiON films, SiOC films, carbon hard masks (amorphous carbon films), tantalum nitride films, titanium nitride films, and spin-on-glass (SOG) films. Examples of organic films include anti-reflective coatings.

[0076] The surface of the substrate may be flat, or it may have a three-dimensional structure such as a trench structure.

[0077] It is preferable that the substrate has been surface-treated beforehand. Examples of surface treatments include cleaning with organic solvents and treatment with UV ozone. UV ozone treatment is preferred as the surface treatment.

[0078] The substrate is placed, for example, in a deposition chamber. By contact between the [A] compound flowing into the deposition chamber and the substrate, a thin film of the [A] compound can be formed on the surface of the substrate.

[0079] When the vaporized [A] compound is brought into contact with the substrate surface, it is preferable that the inside of the deposition chamber be heated in order to promote the formation of a thin film. The lower limit of the temperature inside the deposition chamber is preferably 100°C, more preferably 200°C, and even more preferably 300°C. The upper limit of the above temperature is preferably 800°C, more preferably 600°C, and even more preferably 500°C.

[0080] When the pressure inside the film deposition chamber is reduced during the contact process, the lower limit of the pressure is preferably 10.0 Pa, more preferably 15.0 Pa, and even more preferably 20.0 Pa. The lower limit of the above pressure is preferably 50.0 Pa, more preferably 40.0 Pa, and even more preferably 35.0 Pa.

[0081] [A] The flow rate of the compound can be set appropriately considering the film formation efficiency. [A] The lower limit of the flow rate of the compound is preferably 20 sccm, more preferably 40 sccm, and still more preferably 60 sccm. [A] The upper limit of the flow rate of the compound is preferably 300 sccm, more preferably 200 sccm, and still more preferably 150 sccm. When using an inert gas (e.g., nitrogen gas) and an amine gas (e.g., ammonia gas) as a carrier gas, the lower limit of the flow rate of the inert gas is preferably 5 sccm, more preferably 10 sccm, and still more preferably 15 sccm. The upper limit of the flow rate of the inert gas is preferably 50 sccm, more preferably 40 sccm, and still more preferably 30 sccm. The lower limit of the flow rate of the amine gas is preferably 40 sccm, more preferably 60 sccm, and still more preferably 80 sccm. The upper limit of the flow rate of the amine gas is preferably 200 sccm, more preferably 150 sccm, and even more preferably 120 sccm.

[0082] It is preferable to perform the above contact process in a plasma atmosphere. When using plasma, the substrate is placed in a parallel-plate type plasma generator, and the [A] compound and, if necessary, a carrier gas are introduced into it. The RF frequency used at this time is 13.56 MHz or 400 kHz, and the power can be arbitrarily set within the range of 100 W to 800 W. It is also possible to mix and use RF of these different frequencies.

[0083] The contact time between the substrate and compound [A] can be set appropriately considering the desired film thickness. The lower limit of the contact time is preferably 10 seconds, more preferably 20 seconds, and even more preferably 30 seconds. The upper limit of the above contact time is preferably 1000 seconds, more preferably 600 seconds, and even more preferably 300 seconds.

[0084] The contact process may be repeated multiple times until the boron-containing film reaches a predetermined thickness. The [A] compound can be purged from the film formation chamber, and the [A] compound and, if necessary, a carrier gas can be reintroduced to perform the contact process again.

[0085] (Cleaning process) In this process, the substrate is cleaned after the contact process described above. The cleaning method is not particularly limited, but cleaning with a solvent is preferred. Examples of cleaning methods include casting a solvent onto a substrate with a thin film, or immersing a substrate with a thin film in a solvent.

[0086] As the solvent, the above organic solvents that can be used when vaporizing compound [A] can be suitably used. Among these, ester solvents, ether solvents, or mixtures thereof are preferred, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, or mixtures thereof are more preferred, and a mixture of propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether is even more preferred.

[0087] After the cleaning process, a drying process can be added as needed to manufacture the semiconductor manufacturing substrate.

[0088] (Boron-containing film) The boron-containing film obtained through the above process contains boron atoms, nitrogen atoms, and carbon atoms. As a result, the boron-containing film can exhibit low dielectric constant, high strength, and ion diffusion suppression properties.

[0089] The lower limit of the ratio of the amount of boron atoms to the amount of nitrogen atoms is preferably 0.90, more preferably 0.92, and even more preferably 0.94. The upper limit of the ratio is preferably 1.10, more preferably 1.08, and even more preferably 1.06.

[0090] The lower limit of the amount of carbon atoms is preferably 1 atm%, and more preferably 5 atm%. The upper limit of the amount of carbon atoms is preferably 40 atm%, and more preferably 30 atm%.

[0091] The thickness of the boron-containing film is not particularly limited and can be set appropriately considering the size of the semiconductor device and the required insulation properties. The lower limit of the film thickness is preferably 5 nm, more preferably 10 nm, and still more preferably 15 nm. The upper limit of the film thickness is preferably 80 nm, more preferably 50 nm, and still more preferably 30 nm.

[0092] The upper limit of the dielectric constant of the boron-containing film is preferably 3.0, more preferably 2.5, and even more preferably 2.0. A lower lower limit of the dielectric constant is preferable.

[0093] The lower limit of the elastic modulus of the boron-containing film is preferably 10 GPa, and more preferably 20 GPa. The upper limit of the elastic modulus is preferably 50 GPa, and more preferably 40 GPa.

[0094] (Other processes) A ​​semiconductor substrate can be manufactured by forming wiring, transistors, resistors, capacitors, etc., on a substrate on which a boron-containing film has been formed, using known methods.

[0095] 《Method for Manufacturing a Boron-Containing Film》 The method for manufacturing a boron-containing film according to this embodiment includes a step of bringing a substrate into contact with a boron-containing compound, wherein the boron-containing compound includes at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

[0096] In this embodiment, the boron-containing compound and contact step can preferably be the compound [A] and contact step in the semiconductor substrate manufacturing method described above. The method for manufacturing the boron-containing film may also include the vaporization step and the cleaning step in the semiconductor substrate manufacturing method described above.

[0097] Boron-containing film-forming material According to this embodiment, the boron-containing film-forming material comprises at least one selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

[0098] As the boron-containing film-forming material according to this embodiment, compound [A] in the above-mentioned semiconductor substrate manufacturing method can be suitably used.

[0099] Boron-containing compound: The boron-containing compound according to this embodiment includes at least one selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing aliphatic heterocycle with 1 to 20 carbon atoms. １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4.

[0100] As the boron-containing compound in this embodiment, a compound corresponding to the embodiment of the [A] compound in the above semiconductor substrate manufacturing method in which the nitrogen-containing heterocycle having 1 to 20 carbon atoms in X is a nitrogen-containing aliphatic heterocycle having 1 to 20 carbon atoms can be suitably adopted.

[0101] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0102] [Average film thickness] The average film thickness was determined by measuring the film thickness at nine arbitrary points spaced 5 cm apart, including the center of the thin film formed on a silicon wafer, using a spectroscopic ellipsometer (J.A. WOOLLAM's "M2000D"). The average of these film thicknesses was then calculated.

[0103] <Preparation of film-coated substrates> The following compounds (A-1) to (A-46) (hereinafter also referred to as [A] compounds) were used as raw materials for forming boron-containing films.

[0104]

[0105]

[0106]

[0107]

[0108]

[0109] [Example A-1] (Synthesis of compound (A-1)) Under a nitrogen atmosphere, methylamine hydrochloride (12.8 g) and chlorobenzene (200 ml) are suspended in a container, and BCl ３ A p-xylene solution (approximately 13%, approximately 1.0 mol / l, 200 ml) was slowly added dropwise over 30 minutes under an ice bath. After the addition was complete, the temperature was raised to room temperature and stirred for another 30 minutes. Then, the temperature was raised to 135°C and the reaction was carried out for 20 hours. After the reaction was complete, the insoluble matter was filtered out and the solvent was removed by evaporation. The resulting solid was dried under vacuum to obtain a 2,4,6-trichloro-trimethylborazine precursor as a white solid (10.1 g). １ HNMR (toluene-d ８ ) (2.83,9H).

[0110] A toluene solution (100 ml) of 2,4,6-trichloro-trimethylborazine (5.0 g) was slowly added dropwise with pyrrolidine (11.0 g) under an ice bath. After reacting at room temperature for 5 hours, the generated amine salt was filtered. The filtrate was concentrated by an evaporator to obtain compound (A-1) (5.7 g). １ 1H NMR (toluene-d ８ ) (1.52, 12H), (2.78, 9H), (3.19, 12H)

[0111] [Examples A-2 to A-12] (Synthesis of compounds (A-2) to compounds (A-12)) Compounds (A-2) to compounds (A-12) were obtained in the same manner as in Example A-1, except that the corresponding amine was used instead of pyrrolidine.

[0112] [Example A-13] (Synthesis of compound (A-13)) Under a nitrogen atmosphere, a p-xylene solution (about 13%, about 1.0 mol / l, 200 ml) of BCl ３ was slowly added dropwise to a suspension vessel of ammonium chloride (10.1 g) and chlorobenzene (200 ml) over 30 minutes under an ice bath. After completion of the dropwise addition, the temperature was raised to room temperature and further stirred for 30 minutes. Then, the temperature was raised to 135 °C and reacted for 20 hours. After completion of the reaction, the generated insoluble matter was filtered, and the solvent was distilled off by an evaporator. The obtained solid was dried by vacuum heating to obtain a 2,4,6-trichloroborazine precursor as a white solid (8.2 g). １ 1H NMR (toluene-d8) (4.70, 3H, -NH).

[0113] A toluene solution (100 ml) of 2,4,6-trichloro-trimethylborazine (5.0 g) was slowly added dropwise with pyrrolidine (13.6 g) under an ice bath. After reacting at room temperature for 5 hours, the generated amine salt was filtered. The filtrate was concentrated by an evaporator to obtain compound (A-13) (5.1 g). １ 1H NMR (toluene-d ８ ) (1.54, 12H), (3.16, 12H), (4.41, 3H, -NH)

[0114] [Examples A-14 to A-24] (Synthesis of compounds (A-14) to (A-24)) Compounds (A-14) to (A-24) were obtained in the same manner as in Example A-13, except that the corresponding amine was used instead of pyrrolidine.

[0115] [Example A-25] (Synthesis of compound (A-25)) Under a nitrogen atmosphere, tris(dimethylamino)borane (32.9 g) and N,N-dimethylethylenediamine (20.3 g) were mixed and stirred at a reaction temperature of 80°C for 10 hours. The resulting reaction solution was purified by distillation at 80°C and 5 Torr (666.6 Pa) to obtain N,N-1,3-tetramethyl-1,3,2-diazaboloridine-2-amine (22.9 g). １ 1H NMR (toluene-d ８ ): (2.63, 6H), (2.67, 6H), (3.05, 4H)

[0116] The above-mentioned N,N-1,3-tetramethyl-1,3,2-diazaboloridine-2-amine (5.0 g) and pyrrolidine (2.6 g) were mixed and reacted at 100°C for 3 hours to exchange ligands with dimethylamine, thereby obtaining compound (A-25) (5.0 g). １ 1H NMR (toluene-d ８ ) (1.54, 4H), (2.68, 6H), (3.10, 4H), (3.15, 4H)

[0117] [Examples A-26 to A-36] (Synthesis of Compounds (A-26) to (A-36)) Compounds (A-26) to (A-36) were obtained in the same manner as in Example A-25, except that the corresponding amine was used instead of pyrrolidine.

[0118] [Example A-37] (Synthesis of compound (A-37)) Under a nitrogen atmosphere, tris(dimethylamino)borane (32.9 g) and N,N-dimethyl-1,3-propanediamine (23.4 g) were mixed and stirred at a reaction temperature of 80°C for 10 hours. The resulting reaction solution was purified by distillation at 100°C and 5 Torr (666.6 Pa) to obtain N,N-1,3-tetramethyl-1,3,2-diazaborolinan-2-amine (20.2 g). １ 1H NMR (toluene-d８ ): (1.56, 2H), (2.70, 12H), (2.75, 4H)

[0119] N,N-1,3-Tetramethyl-1,3,2-diazaborolinane-2-amine (5.0 g) and pyrrolidine (2.3 g) were mixed and reacted at 100 °C for 3 hours to perform ligand exchange with dimethylamine to obtain compound (A-37) (4.9 g). １ H NMR (toluene-d ８ ): (1.52 - 1.56, 6H), (2.70, 6H), (2.75, 4H), (3.15, 4H)

[0120] [Examples A-38 to A-46] (Synthesis of compound (A-38) to compound (A-46)) Compounds (A-38) to compounds (A-46) were obtained in the same manner as in Example A-37, except that the corresponding amine was used instead of pyrrolidine.

[0121] [Example 1-1] A boron-containing film was formed using an Oxford ALD film-forming apparatus [FlexAL ALD]. A 2 cm square coupon substrate cut from a silicon wafer was placed in the chamber, the pressure in the chamber was reduced to 0.2 Torr (26.7 Pa), and then the temperature in the chamber was heated to 400 °C. The temperature of the container containing compound (A-1) was heated to 50 °C, and the vaporized compound (A-1) was introduced into the chamber. N ２ gas 25 sccm, NH ３ gas 100 sccm was used as the reaction gas, and the vaporized compound on the silicon wafer was contacted at 500 W of RF plasma to prepare a film-coated substrate (S1-1). The film thickness of the thin film was 20 nm.

[0122] [Examples 1-2 to 1-46] Film-coated substrates (S1-2) to (S1-46) were prepared in the same manner as in Example 1-1, except that the [A] compounds of the types shown in Table 1 below were used.

[0123] [Comparative Example 1-1] A film-coated substrate (s-1) was prepared in the same manner as in Example 1-1, except that BCl ３ gas (S-!) was used instead of the [A] compound.

[0124] <Evaluation> The dielectric constant of the thin film was evaluated using the above-mentioned film-coated substrate by the following method. The evaluation results are shown in Table 1 below.

[0125] <Evaluation of Dielectric Constant> A sample for dielectric constant measurement was prepared by depositing aluminum onto the above-mentioned film-coated substrate to form an electrode pattern. The dielectric constant (k) was measured using the CV method with an LCR meter at a frequency of 100 kHz. A dielectric constant of less than 2.5 was evaluated as "A" (good), and a dielectric constant of 2.5 or more was evaluated as "B" (poor).

[0126]

[0127] As is clear from Table 1, the film-coated substrates obtained in the examples all had lower dielectric constants compared to the comparative examples.

[0128] The semiconductor substrate manufacturing method of the present invention enables the efficient production of high-quality semiconductor substrates having a low dielectric constant boron-containing film. The boron-containing film manufacturing method, boron-containing film forming material, and boron-containing compound of the present invention enable the efficient production of a low dielectric constant boron-containing film. Therefore, these can be suitably used in the manufacture of semiconductor devices, where further miniaturization is expected in the future.

Claims

1. A method for manufacturing a semiconductor substrate, comprising the step of bringing a substrate into contact with a boron-containing compound, wherein the boron-containing compound comprises at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) 2. The method for manufacturing a semiconductor substrate according to claim 1, wherein the monovalent group having a nitrogen-containing heterocycle having 1 to 20 carbon atoms has a nitrogen atom in which the nitrogen atom constituting the nitrogen-containing heterocycle is bonded to the boron atom in formulas (1) to (2).

3. In the above formula (a), R ４ ~ R ５ each independently represents a monovalent group having a nitrogen-containing heterocyclic ring with 1 to 20 carbon atoms, a substituted or unsubstituted monovalent linear hydrocarbon group with 1 to 10 carbon atoms, or a substituted or unsubstituted monovalent aromatic hydrocarbon group with 6 to 20 carbon atoms. The method for manufacturing a semiconductor substrate according to claim 1.

4. In the above formula (a), R ６ The method for manufacturing a semiconductor substrate according to claim 1, wherein is a hydrogen atom or a methyl group.

5. In the above formula (1), R １ The method for manufacturing a semiconductor substrate according to claim 1, wherein each of them is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, a monovalent linear hydrocarbon group having 1 to 10 carbon atoms, or a hydrogen atom.

6. In the above formula (2), R １ The method for manufacturing a semiconductor substrate according to claim 1, wherein each of them is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms and a monovalent chain-like hydrocarbon group having 1 to 10 carbon atoms.

7. In the above formula (2), R ２ ~R ３ The method for manufacturing a semiconductor substrate according to claim 1, wherein is a hydrogen atom.

8. The method for manufacturing a semiconductor substrate according to claim 1, wherein in formula (2) above, n is 2 or 3.

9. A method for manufacturing a semiconductor substrate according to any one of claims 1 to 8, wherein the temperature of the substrate is 100°C or higher and 400°C or lower.

10. A method for manufacturing a semiconductor substrate according to any one of claims 1 to 8, wherein the above contact step is performed in a plasma atmosphere.

11. A method for producing a boron-containing film, comprising the step of bringing a substrate into contact with a boron-containing compound, wherein the boron-containing compound comprises at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) 12. A boron-containing film-forming material comprising at least one compound selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing heterocycle with 1 to 20 carbon atoms, or a monovalent group represented by the following formula (a). R １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4. (In the above formula (a), R ４ ~R ５ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms, or R ４ ~R ５ These can be combined with each other to form a nitrogen-containing heterocycle with 3 to 10 member atoms, along with the nitrogen atoms to which they are bonded. ６ (where * is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) 13. A boron-containing compound comprising at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2). (In the above formulas (1) and (2), X is independently a monovalent group having a nitrogen-containing aliphatic heterocycle with 1 to 20 carbon atoms. １ ~R ３ Each of these is independently a monovalent organic group having 1 to 40 carbon atoms or a hydrogen atom. n is an integer from 1 to 4.

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