JP2009088119A - Low dielectric-constant interlayer insulation film, substrate having the same, and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation film that has a low dielectric constant, and has improved characteristics of stability with time in the dielectric constant, mechanical strength, adhesiveness, and the like. <P>SOLUTION: A composition for forming a film containing an organic compound and a hole-forming agent is applied onto a substrate to form coating on the substrate, and the coating is cured and is treated by a supercritical medium containing a pore-sealing agent, thus obtaining the low dielectric-constant interlayer dielectric. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a low dielectric constant interlayer insulating film having good film characteristics used for electronic devices and the like, a substrate having the same, and a method for manufacturing the same.

  In recent years, in the field of electronic materials, with the progress of higher integration, more functions, and higher performance, circuit resistance and capacitor capacity between wirings have increased, leading to an increase in power consumption and delay time. In particular, an increase in delay time is a major factor in reducing the signal speed of the device and the occurrence of crosstalk. Therefore, in order to reduce the delay time and increase the device speed, it is necessary to reduce parasitic resistance and parasitic capacitance. ing. As a specific measure for reducing the parasitic capacitance, an attempt has been made to cover the periphery of the wiring with a low dielectric interlayer insulating film.

  Such an interlayer insulating film is required to have excellent heat resistance capable of withstanding a subsequent process such as a thin film forming process at the time of manufacturing a mounting substrate, chip connection, and pinning, and chemical resistance capable of withstanding a wet process. Furthermore, in recent years, low resistance Cu wiring is being introduced from Al wiring, and along with this, planarization by CMP (Chemical Mechanical Polishing) is common, and can withstand this process. High mechanical strength is required.

Several resin compositions for forming an interlayer insulating film have already been proposed.
For example, Patent Document 1 describes a high heat resistant resin having polyarylene ether as a basic main chain as a high heat resistant insulating film. For example, Patent Document 2 describes a thermosetting monomer such as a diadamantane monomer substituted with an aryl group and a carbon-carbon triple bond. It is described that a resin incorporating such a monomer becomes a low dielectric constant material.
However, in order to realize a high-speed device, the interlayer dielectric film using these resins is preferably further reduced in dielectric constant. In addition, adhesion to a substrate such as a silicon wafer is low, and problems such as film peeling during wiring processing may occur.

For example, Patent Document 3 describes a film-forming composition comprising a compound having a cage structure such as a diadamantane structure and a pore-forming agent. It is described that such a composition can provide an insulating material having good characteristics such as dielectric constant, mechanical strength, and adhesion.
However, in order to realize a high-speed device, it is desirable to further reduce the dielectric constant. In addition, there is a case in which moisture enters a hole introduced for the purpose of lowering the dielectric constant and the dielectric constant increases with time. It is widely known that this moisture not only increases the dielectric constant but also greatly affects the reliability of the semiconductor device.
JP 2002-534546 A Special table 2004-504455 gazette JP 2006-265513 A

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide an insulating film having a low dielectric constant and good dielectric constant stability over time, mechanical strength, adhesion, heat resistance, and chemical resistance. Moreover, it aims at providing the board | substrate which has such an insulating film, and its manufacturing method.

  The inventor diligently studied, and after forming a film on a substrate using a composition containing an organic compound and a pore-forming agent, a low dielectric constant interlayer insulating film obtained by performing a special treatment is the above problem The present invention has been completed.

The present invention includes the following (1) to (4).
(1) A film-forming composition containing an organic compound and a pore-forming agent is applied onto a substrate to form a film on the substrate, the film is cured, and then the film contains a pore sealant. Low dielectric constant interlayer insulation film obtained by processing with a critical medium.
(2) The low dielectric constant interlayer insulating film according to (1), wherein the pore sealant is a silane compound.
(3) A substrate with an insulating film, comprising the low dielectric constant interlayer insulating film according to (1) or (2) above on the substrate.
(4) A film-forming composition containing an organic compound and a pore-forming agent is applied onto a substrate to form a film on the substrate, the film is cured, and then the film contains a pore sealant. A method for manufacturing a substrate with an insulating film, wherein the substrate having a low dielectric constant interlayer insulating film is obtained by treatment with a critical medium.

  According to the present invention, it is possible to provide an insulating film having a low dielectric constant and good dielectric constant stability, mechanical strength, adhesion, heat resistance, and chemical resistance. In addition, a substrate having such an insulating film and a manufacturing method thereof can be provided.

Hereinafter, the present invention will be described in detail.
The present invention comprises applying a film-forming composition containing an organic compound and a pore-forming agent on a substrate to form a film on the substrate, curing the film, and then including the pore sealant. It is a low dielectric constant interlayer insulating film obtained by processing with a supercritical medium.
Hereinafter, such a low dielectric constant interlayer insulating film is also referred to as “the insulating film of the present invention”.

<Film forming composition>
First, a film forming composition (hereinafter, also referred to as “the composition of the present invention”) used for obtaining the insulating film of the present invention will be described.
The composition of the present invention includes an organic compound and a pore-forming agent.
Here, the organic compound is not particularly limited as long as it is an organic compound serving as a matrix of the insulating film of the present invention.
For example, it is an organic compound such as polybenzoxazole, polyimide, polyarylene (ether), and an organic compound having a cage structure (hereinafter also referred to as “cage structure compound”). Among these, the cage-type structural compound is preferable.

<Cage-type structural compound>
The cage structure compound will be described.
In the cage structure compound, the “cage structure” means that the volume is determined by a plurality of rings formed by covalently bonded atoms, and points located within the volume cannot be separated from the volume without passing through the ring. Refers to such molecules.
For example, the adamantane structure is a cage structure. In contrast, a cyclic structure having a single bridge, such as norbornane (bicyclo [2,2,1] heptane), is not a cage structure because the ring of a single bridged cyclic compound does not define volume.

The total number of carbon atoms forming such a cage structure is preferably 10-30, more preferably 10-18, and even more preferably 10-14.
Here, the carbon atom does not include a linking group substituted with a cage structure or a carbon atom of the substituent. For example, 1-methyladamantane is composed of 10 carbon atoms and 1-ethyldiadamantane is composed of 14 carbon atoms.

Further, the ratio of carbon atoms forming the cage structure in the total number of carbon atoms constituting the composition of the present invention is preferably 30% or more, more preferably 50 to 95%, and still more preferably 60% to 90%. This ratio means a value calculated from the chemical structure of the organic compound contained in the composition of the present invention to be used.
This ratio can be adjusted by the ratio of the cage structure compound in the organic compound contained in the composition of the present invention.

  The cage structure is preferably a saturated hydrocarbon, and preferable examples include diamond-like structures such as adamantane, diadamantane, triadamantane, tetraadamantane, dodecahedran, etc. in terms of having high heat resistance, In terms of obtaining a lower dielectric constant, examples include diadamantane, triadamantane, and tetraadamantane structures, and in terms of easy synthesis, examples include adamantane and diadamantane structures. In view of the above conditions, adamantane and diadamantane structures are more preferred, with a diadamantane structure being even more preferred.

The cage structure may have one or more substituents. Examples of the substituent include a halogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and an alkenyl group having 2 to 10 carbon atoms. Group, an alkynyl group having 2 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an acyl group having 2 to 10 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, and a silyl group.
Among these, preferred substituents are a fluorine atom, a bromine atom, a linear, branched or cyclic alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, and a silyl group. It is.
These substituents may be further substituted with another substituent.

  The cage structure is preferably 1 to 4 valent, more preferably 2 to 3 valent, and still more preferably 2 valent. At this time, the group bonded to the “cage structure” may be a monovalent or higher substituent or a divalent or higher linking group. Here, “valence” means the number of bonds.

The cage structure compound may be a low molecular compound or a high molecular compound (for example, a polymer), and a polymer is preferable.
When the cage structure compound is a low molecular weight compound, the low molecular weight compound is polymerized by heating after forming a film on the substrate and cured to form a film. The mass average molecular weight is preferably 150 to 3,000, more preferably 200 to 2,000, and still more preferably 220 to 1,000.
When the cage structure compound is a polymer, the mass average molecular weight is preferably 1,000 to 500,000, more preferably 5,000 to 300,000, and still more preferably 1,000 to 200,000. . The polymer having a cage structure may be a resin having a molecular weight distribution.

  The cage structure may be incorporated into the polymer main chain as a monovalent pendant group. Preferable polymer main chain to which the cage structure is bonded includes, for example, polyarylene, polyarylene ether, polyether, polyacetylene, polyethylene, etc. Among them, polyarylene ether and polyacetylene are more preferable from the viewpoint of good heat resistance. .

When the cage structure compound is a polymer, the cage structure is preferably a part of the polymer main chain, and in this form, the cage structure is directly single-bonded or a suitable divalent linking group. Connected by Examples of the linking group include, for example, —C (R ₁₁ ) (R ₁₂ ) —, —CH═CH—, —C≡C—, an arylene group, —O—, —Si (R ₁₃ ) (R ₁₄ ). -Or a group in which these are combined, and among them, -CH = CH-, -C≡C-, -O-, -Si (R ₁₃ ) (R ₁₄ )-or a combination thereof is preferable.
Here, R < ₁₁ > -R < ₁₄ > represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and an alkoxy group each independently. These linking groups may be substituted with a substituent.

  The cage structure-based compound may have one kind of cage structure in its molecule, or may contain two or more kinds.

The cage structure compound is preferably thermosetting.
Preferred examples of the thermosetting cage structure compound include a cage structure compound having a reactive group that forms a covalent bond with another molecule by heat. Such a reactive group is not particularly limited, but a substituent that causes a cycloaddition reaction or a radical polymerization reaction is preferably exemplified. Among these, there are combinations of a group having a double bond (vinyl group, allyl group, etc.), a group having a triple bond (ethynyl group, phenylethynyl group, etc.), and a diene group and a dienophile group for causing a Diels-Alder reaction. A combination of an ethynyl group and a phenylethynyl group is more preferable.

  For example, the compound represented by the general formula (I) described later, which is a cage-type structural compound, is heated and then applied to a substrate, whereby the remaining ethynyl group is cured by polymerization reaction and becomes an organic solvent. On the other hand, it becomes insoluble and forms a film.

  Although the specific example ((A-1)-(A-26)) of the cage structure type compound is shown below, it is not limited to these. n represents a positive number.

  The cage structure compounds represented by the specific examples shown here can be synthesized by known methods, but commercially available products may be used.

<Compound represented by formula (I)>
The cage structure compound is preferably a compound represented by the following formula (I).

In the formula (I), R represents a hydrogen atom, an alkyl group (preferably 1 to 10 carbon atoms), an alkenyl group (preferably 2 to 10 carbon atoms), an alkynyl group (preferably 2 to 10 carbon atoms), an aryl group ( Preferably it represents C6-C20) or a silyl group (preferably C0-20).
R is preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a silyl group having 0 to 20 carbon atoms, and is a hydrogen atom or a silyl group having 0 to 10 carbon atoms. More preferably.

  When R is other than a hydrogen atom, R may further have a substituent. Examples of the substituent include a halogen atom (a fluorine atom, a crawl atom, a bromine atom, or an iodine atom), an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an acyl group, an aryloxy group, an arylsulfonyl group, a nitro group, A cyano group, a silyl group, etc. are mentioned.

  In Formula (I), m represents an integer of 1 to 14, preferably an integer of 1 to 4, more preferably an integer of 1 to 3, and further preferably 2 or 3.

In the formula (I), X is a halogen atom, an alkyl group (preferably 1 to 10 carbon atoms), an alkenyl group (preferably 2 to 10 carbon atoms), an aryl group (preferably 6 to 20 carbon atoms), a silyl group. (Preferably having 0 to 20 carbon atoms).
X is preferably a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or a silyl group having 0 to 20 carbon atoms. It is more preferable that they are -4 alkenyl groups and C0-10 silyl groups.

  X may further have a substituent. Examples of such substituents include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, or iodine atoms), alkyl groups, alkenyl groups, alkynyl groups, aryl groups, acyl groups, aryloxy groups, arylsulfonyl groups, nitro groups, Group, cyano group, silyl group and the like.

  In formula (I), n represents an integer of 0 to 13, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and still more preferably 0 or 1.

  A compound represented by the formula (I) in which R is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, m = 1 to 3, and n = 0 is preferable as the cage structure compound. .

  As the compound represented by the formula (I), a compound in which the compound represented by the formula (I) is bonded by a plurality of single bonds or linking groups can also be used. Examples include those in which the cage structure portion of the formula (I) is linked by a C—C single bond, such as a biadamantane skeleton and a bidiamantane skeleton, and a polymer of the formula (I).

  Specific examples ((D-1) to (D-16)) of the compound represented by the formula (I) are shown below, but are not limited thereto.

  The compound represented by the formula (I) is 1-ethynyldiadamantane, 4-ethynyldiadamantane, 4,9-diethynyldiadamantane, 1,6-diethynyldiadamantane, 1,4-diethynyldiadamantane, 1,4,9-triethynyldiadamantane is preferable, and 4,9-diethynyldiadamantane and 1,6-diethynyldiadamantane are more preferable.

The compound represented by the formula (I) is obtained by reacting with bromine in the presence or absence of an aluminum bromide catalyst using a commercially available diadamantane as a raw material to introduce a bromine atom at a desired position, followed by aluminum bromide, A 2,2-dibromoethyl group is introduced by reacting with vinyl bromide and Friedel-Crafts in the presence of a Lewis acid such as aluminum chloride or iron chloride, followed by de-HBr conversion with a strong base to convert to an ethynyl group. Specifically, Macromolecules., 1991, 24, 5266-5268, Macromolecules., 1995, 28, 5554-5560, Journalof Organic Chemistry., 39, 2995-3003 (1974), etc. It can be synthesized according to the method described in 1.
In addition, an alkyl group or a silyl group can be introduced by anionizing a hydrogen atom of a terminal acetylene group with butyllithium or the like and reacting this with an alkyl halide or a silyl halide.

  The synthesis of the compound represented by formula (I) is preferably carried out in an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the raw material monomer and does not adversely affect the characteristics of the insulating film of the present invention. For example, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and acetophenone, ester solvents such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, γ-butyrolactone and methyl benzoate, ether solvents such as dibutyl ether and anisole Solvent, aromatic hydrocarbon solvents such as toluene, xylene, mesitylene, 1,3,5-triisopropylbenzene, amide solvents such as N-methylpyrrolidinone, dimethylacetamide, carbon tetrachloride, dichloromethane, chloroform, 1,2 -Halogen solvents such as dichloroethane, chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, and aliphatic hydrocarbons such as hexane, heptane, octane, and cyclohexane Such as solvent, and the like.

  The preferable range of the mass average molecular weight of the compound represented by the formula (I) is 1,000 to 500,000, more preferably 5,000 to 300,000, and particularly preferably 10,000 to 200,000.

<Void forming agent>
Next, the pore forming agent contained in the composition of the present invention will be described.
The pore forming agent contained in the composition of the present invention is a substance having a function of forming pores in a film formed by the composition of the present invention. For example, a film formed by the composition of the present invention containing a pore-forming agent can be easily detached by applying energy such as heating, electron beam irradiation, UV irradiation, etc., and pores can be formed in the film. It is a possible pore forming agent.

  Examples of the pore forming agent include various polymers having a thermal decomposition temperature lower than that of the organic compound.

Examples of such polymers include polyvinyl aromatic compounds (polystyrene, polyvinyl pyridine, halogenated polyvinyl aromatic compounds, etc.), polyacrylonitrile, polyalkylene oxide (polyethylene oxide, polypropylene oxide, etc.), polyethylene, polylactic acid, polysiloxane, Polycaprolactone, polycaprolactam, polyurethane, polymethacrylate (such as polymethyl methacrylate) or polymethacrylic acid, polyacrylate (such as polymethyl acrylate) and polyacrylic acid, polydiene (such as polybutadiene and polyisoprene), polyvinyl chloride, polyacetal, and amine Capped alkylene oxide (from Huntsman Corp. Jeffamine ™ polyether Commercially available as ruamine).
In addition, polyphenylene oxide, poly (dimethylsiloxane), polytetrahydrofuran, polycyclohexylethylene, polyethyloxazoline, polyvinylpyridine, and the like may be used.

Among these, polystyrene can be suitably used as a pore forming agent. Examples of polystyrene include anionic polymerized polystyrene, syndiotactic polystyrene, unsubstituted and substituted polystyrene (for example, poly (α-methylstyrene)), and unsubstituted polystyrene is preferred.
Polystyrene is mainly used at about 420 ° C. to 450 ° C. when a thermosetting mixture of polycyclopentadienone and polyacetylene is used as the organic compound as described in, for example, WO 98/11149. Since it decomposes into a monomer, heating to this temperature is preferable because the monomer diffuses out of the film made of the thermosetting mixture and forms pores.

The pore-forming agent may react with the organic compound in the composition of the present invention or in the film before the curing treatment. For example, when the organic compound is a polymer, the pore-forming agent may form a polymer chain block or pendant (suspended) substitution in the organic compound.
Reactivity such as vinyl, acrylate, methacrylate, allyl, vinyl ether, maleimide, styryl, acetylene, nitrile, furan, cyclopentadienone, perfluoroethylene, benzocyclobutene (BCB), pyrone, propiolate or ortho-diacetylene groups The thermoplastic polymer containing groups can form chemical bonds with the organic compound. Since such a thermoplastic polymer is removed from the film by heating the film, pores can be left in the film.

Examples of such thermoplastic polymers are polystyrene, polyacrylate, polymethacrylate, polybutadiene, polyisoprene, polyphenylene oxide, polypropylene oxide, polyethylene oxide, poly (dimethylsiloxane), polytetrahydrofuran, polyethylene, polycyclohexylethylene, polyethyl. Examples include oxazoline, polycaprolactone, polylactic acid, and polyvinylpyridine.
The polymer designed to react with the organic compound may be a homopolymer, a copolymer or a mixture thereof.

  Such thermoplastic polymers may also have one or more reactive groups. Depending on the number and type of reactive groups, whether the thermoplastic polymer binds to the organic compound in a pendant manner or as a block varies. Such thermoplastic polymers can be structurally linear, branched, hyperbranched, dendritic or star-like.

  Suitable molecular weights of various polymers as pore forming agents are various such as compatibility between the organic compound and a film obtained by polymerization and curing, and pore size in the insulating film of the present invention. It can be appropriately selected depending on various factors. However, generally, the number average molecular weight (Mn) of various polymers as the pore forming agent is preferably 2,000 to 100,000. More preferably, the number average molecular weight is in the range of 5,000 to 50,000, and more preferably 5,000 to 35,000. A polymer having a narrow molecular weight distribution (Mw / Mn: 1.01 to 1.5) is preferable.

  In the composition of the present invention, the pore forming agent may be a granular material having a size corresponding to the size of the pores of the insulating film of the present invention. For example, the average particle size is preferably 0.5 to 50 nm, and more preferably 0.5 to 20 nm.

Examples of the thermoplastic polymer having such an average particle size include hyperbranched polymer systems such as dendrimers and latex particles, particularly crosslinked polystyrene-containing latexes.
More specifically, Dendritech, Inc. Also available through Polymer J. (Tokyo), Vol. 17, 117 (1985), described by Tomalia et al., Polyamidoamine (PAMAM) dendrimer, polypropyleneimine polyamine (DAB-Am) dendrimer available from DSM Corporation, Flechette type polyether dendrimer (J. Am. Chem. Soc. , Vol. 112, 7638 (1990), Vol. 113, 4252 (1991)), a parsec type liquid crystal monodendron, a dendronized polymer, and their self-assembled polymers (Nature, Vol. 391). 161 (1998), J. Am. Chem. Soc., Vol. 119, 1539 (1997) by Percec et al.), Boltlon H series dendritic polyester. (Commercially available from Perstorp AB).

  Further, the pore forming agent may be an organic solution. The organic solution useful as a pore-forming agent is preferably one that diffuses at a temperature lower than the thermal decomposition temperature of the organic compound. When the organic solution functions as a pore forming agent, for example, pores are formed by the following mechanism. The organic compound (for example, cage structure compound, its prepolymer or partially crosslinked polymer) in the composition of the present invention is swollen with an organic solution in a liquid or gaseous state, and then the swollen organic compound is subjected to structural integrity. Cross-linking to increase, then the organic solution is removed by vacuum or heating to form vacancies.

  Examples of organic solutions that can be used as a pore-forming agent include mesitylene, pyridine, triethylamine, N-methylpyrrolidinone (NMP), methylbenzoate, ethylbenzoate, butylbenzoate, cyclopentanone, cyclohexanone, cycloheptanone, cyclohexane. Like octanone, cyclohexyl pyrrolidinone, dibenzyl ether, diglyme, triglyme, diethylene glycol ethyl ether, diethylene glycol methyl ether, dipropylene glycol methyl ether, dipropylene glycol dimethyl ether, propylene glycol phenyl ether, propylene glycol methyl ether, tripropylene glycol methyl ether Ether or hydroxy ether, toluene, xylene, benzene , Dipropylene glycol monomethyl ether acetate, dichlorobenzene, propylene carbonate, naphthalene, diphenyl ether, butyrolactone, dimethylacetamide, dimethylformamide. These may be used alone or in combination.

The organic compound (eg, cage structure-based compound) and the pore-forming agent are cured before the pore-forming agent is diffused or decomposed during the curing process (heating, etc.) after film formation. Preferably, the pore-forming agent is preferably selected so that it completely or substantially completely diffuses or decomposes before the film is diffused or decomposed.
When the curing treatment is heating, it is preferable that the difference between the temperature at which the organic compound is crosslinked and the temperature at which the pore forming agent is diffused or decomposed is large in terms of wide selection of the pore forming agent.

The composition of the present invention contains the organic compound and the pore-forming agent. And the organic solvent which melt | dissolves these at least one part may be included.
Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and acetophenone, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, γ-butyrolactone, ester solvents such as methyl benzoate, dibutyl ether, Ether solvents such as anisole, aromatic hydrocarbon solvents such as toluene, xylene, mesitylene, 1,3,5-triisopropylbenzene, amide solvents such as N-methylpyrrolidinone and dimethylacetamide, carbon tetrachloride, dichloromethane, Halogen solvents such as chloroform, 1,2-dichloroethane, chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, hexane, heptane, octane, cyclohexane Like aliphatic hydrocarbon solvents.

<Additives>
In addition, the composition of the present invention may further contain an additive as long as various properties of the insulating film are not impaired. Examples of the additive include a radical generator, a nonionic surfactant, a fluorine-based nonionic surfactant, and an adhesion promoter such as a silane coupling agent.

Representative examples of adhesion promoters here are silanes, preferably alkoxy silanes (eg trimethoxyvinylsilane, triethoxyvinylsilane, tetraethoxysilane, phenyltrimethoxylane, allyltrimethoxysilane, divinyldiethoxysilane), etc. Organosilane, acetoxysilane (for example, vinyltriacetoxysilane, 3-aminopropyltrimethoxysilane), and hydrolyzate or dehydrated condensate thereof, hexamethyldisilazane [(CH ₃ ) ₃ —Si—NH—Si (CH ₃ ) ₃ ], or aminosilane couplers, such as γ-aminopropyltriethoxysilane, or chelates (for example, aluminum monoethyl acetoacetate diisopropylate [((isoC ₃ H ₇ O ₂ Al (OCOC ₂ H ₅ CHCOCH ₃ ))], aluminum alkoxide) and the like. You may mix and use these materials. Moreover, you may use what is marketed as an adhesion promoter.

  The additive may be used by dissolving in a solvent. Examples of the solvent include acetone, propanol, cyclohexanone, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, γ-butyrolactone, anisole, mesitylene, and 1,2-dichlorobenzene. This solvent can also be used as the organic solvent.

<Composition of the present invention>
The composition of the present invention contains the organic compound and the pore-forming agent. And it may contain the said organic solvent and the said additive as needed.
Moreover, it is preferable that the composition of this invention contains the catalyst which accelerates | stimulates the polymerization reaction of the said organic compound. For example, it is preferable to include a metal catalyst that promotes the polymerization of a carbon-carbon triple bond in the polymerization reaction of the compound represented by the above formula (I). This is because the reaction time of the organic compound can be shortened and the reaction temperature can be lowered.

The concentration of the total solid content contained in the composition of the present invention is preferably 3 to 50% by mass, more preferably 5 to 35% by mass, and further preferably 7 to 20% by mass.
Content of the said organic compound in the composition of this invention is 10-95 mass% generally with respect to the total solid contained in the composition of this invention, Preferably it is 30-90 mass%.

  Further, the ratio of the total carbon number of the cage structure to the total carbon number in the total solid content contained in the composition of the present invention is preferably 30% or more, more preferably 30 to 100%, more preferably It is 50 to 95%, more preferably 60% to 90%.

  Further, the content of the pore forming agent in the composition of the present invention is adjusted so as to produce a desired porosity (volume% of pores in the insulating film of the present invention). Usually, the ratio of the pore-forming agent to the total mass of the organic compound and the pore-forming agent in the composition of the present invention is preferably 2 to 70% by mass, more preferably 5 to 60% by mass. -50 mass% is more preferable.

  In addition, the content of the additive in the composition of the present invention has an appropriate range depending on the use of the additive or the solid content concentration in the composition of the present invention. Preferably they are 0.001 mass%-10 mass% with respect to the whole quantity, More preferably, they are 0.01 mass%-5 mass%, More preferably, they are 0.05 mass%-2 mass%.

  The organic compound and the pore forming agent may be simply mixed or partially reacted in the composition of the present invention.

  The composition of the present invention is such a composition.

  The insulating film of the present invention is an insulating film obtained by a production method including a process of applying the composition of the present invention as described above on a substrate to form a film on the substrate and curing the film.

  Here, the substrate is not particularly limited. For example, a substrate that is usually used when manufacturing a semiconductor can be used. For example, a silicon wafer can be preferably used.

  Moreover, the method of apply | coating the composition of this invention on the said board | substrate is not limited, For example, a conventionally well-known method is applicable. For example, methods such as a spin coating method, a roller coating method, a dip coating method, and a scanning method can be applied.

Moreover, the method of hardening after apply | coating to the said board | substrate is not specifically limited. For example, the method of giving energy, such as a heating, electron beam irradiation, UV irradiation, wet processing, plasma irradiation, is mentioned. In the case of heating, for example, a conventionally known method can be applied. For example, generally used hot plate heating, a method using a furnace, light irradiation heating using a xenon lamp by RTP (Rapid Thermal Processor) or the like can be applied. A conventionally known method can also be applied when applying electron beam irradiation, UV irradiation, wet processing, plasma irradiation, or the like.
The method for curing is preferably heating.

  In the heating, after applying the composition of the present invention to the substrate, if the composition of the present invention contains the organic solvent, the organic solvent is removed (dried) to form a film of the organic compound or the like. Preferably, it is carried out under conditions sufficient to cause further polymerization (curing) of the organic compound. The temperature for heating can be appropriately selected depending on the physical properties of the organic compound and the like.

  For example, when the compound represented by the above general formula (I) is used as the organic compound, the composition of the present invention is applied on the substrate by the method as described above, and then 100 to 450 ° C. (preferably 200 The heat treatment is performed at ˜420 ° C., more preferably at 350 ° C. to 400 ° C. for 1 minute to 2 hours (preferably 10 minutes to 1.5 hours, more preferably 30 minutes to 1 hour). By heating under such conditions, the ethynyl group remaining in the composition of the present invention undergoes a polymerization reaction to form a film.

  Such heating may be performed in two or more times. Moreover, it is preferable to heat in a nitrogen atmosphere in order to prevent thermal oxidation by oxygen.

By performing such a curing treatment, a film is usually formed, and at the same time, a pore-forming agent in the film is detached, and a hole is formed in the film. Depending on the type of pore forming agent used and the curing conditions, pores are formed in at least a part of the film.
On the other hand, pores may not be formed depending on the curing conditions. Further, depending on the type of pore forming agent, it may not be detached by the curing process. In such a case, the pore forming agent may be removed from the film by further heating under different conditions or applying energy such as electron beam irradiation or UV irradiation to the film. However, since the void forming agent remaining in the film can be removed by performing a treatment with a supercritical medium later, not all the pore forming agents have been removed from the film by the curing treatment. Also good.

The process of applying the composition of the present invention on a substrate to form a film on the substrate, curing the film, and simultaneously forming pores in the film will be specifically exemplified.
For example, when the pore-forming agent is a thermoplastic polymer or a particulate material, and the composition of the present invention contains the organic solvent, the organic solvent is heated to a medium temperature (for example, after application of the composition of the present invention to the substrate) 40 to 250 ° C.) and removed (dried). Subsequently, the organic compound is crosslinked by rapidly heating to a sufficient temperature. Thereafter, the pore-forming agent is heated to a temperature sufficient to diffuse or decompose.
Drying (removing the organic solvent), curing, and air-hole formation agent diffusion or decomposition may be performed by separate heating steps (multi-stage heating), or may be performed by a single heating step. When a multi-stage heating stage is used, any one or more of drying (solvent removal), curing, and air-hole formation agent decomposition or decomposition is performed in any heating step.

  Also, for example, a substrate coated with the composition of the present invention is heated to a temperature sufficient to cause rapid curing, but below the decomposition temperature or transpiration temperature of the pore former. Suitable methods for performing this rapid heating step include, for example, baking on a hot plate and rapid thermal annealing under an infrared lamp. In this embodiment, the composition of the present invention is first subjected to an initial curing step at a rate of at least 20 ° C./second, more preferably at least 50 ° C./second, preferably to a temperature above 300 ° C., more preferably above 350 ° C. The temperature is raised. The holding time at the final temperature of the initial curing step is preferably 10 to 400 minutes. In this initial curing step, it is sufficient that the matrix (film) is sufficiently cured to fix the pore forming agent and the organic compound, and it is not necessary to completely cure. At least one additional heating step is then performed to completely complete the cure and optionally to dissipate or decompose the pore former. The temperature of this additional heating step is preferably above 370 ° C, more preferably above 390 ° C. The holding time in the additional heating step is preferably 10 to 400 minutes.

  Also, for example, at a rate of at least 20 ° C./second, preferably at least 50 ° C./second, a temperature sufficient to cause both curing and evacuation or decomposition of the pore former (eg, 300-450 ° C., A single rapid heating step to a holding time of 10 to 400 minutes) is performed. This single rapid heating step can be performed after drying or without providing a separate drying step.

  By such treatment, a film in which pores are formed and a substrate having the film can be obtained.

Here, each process of formation of said film | membrane, hardening (heating etc.), and formation of a void | hole may each be performed in multiple times. As a result, the coating on the substrate may be two or more layers.
Also, after obtaining a film with pores formed at least in part or a film without holes formed, the film is a groove as desired in the manufacture of integrated circuit articles and other microelectronic devices, In order to form vias and holes, etching or imaging may be performed by a known method.
Moreover, you may perform the process which dries the said film | membrane before hardening.
The film may be subjected to chemical mechanical polishing (CMP). Thereby, the film can be smoothed.

The film thickness of the film is not particularly limited by such treatment, but is preferably 0.001 to 100 μm, more preferably 0.01 to 10 μm, and particularly preferably 0.1 to 1 μm. preferable.
Here, the film thickness is arbitrary, such as a reflection interference type film thickness meter generally used in this field, an optical film thickness measuring method such as a spectroscopic ellipsometry method, or a physical measurement such as a stylus step meter. It can be measured by the method. The film thickness of the film also means a value obtained by measurement by the same method.

In the film obtained by such treatment, it is preferable that at least 80 percent, more preferably at least 90 percent, and further preferably at least 95 percent of the pore-forming agent is removed. The degree to which the pore-forming agent is removed can be confirmed by techniques such as infrared spectroscopy, transmission electron microscopy, and the like. For example, if the pore former is a thermoplastic polymer, removal of the pore former may occur when the pore former decomposes into low molecular weight species that can diffuse out of the coating. For example, in the case of thermoplastic polymer pore formers, it is preferred that at least 80 percent, more preferably at least 90 percent, and even more preferably at least 95 percent decompose into its monomeric units or smaller units.
The concentration of pores in the film is preferably 5 to 60% by volume, more preferably 10 to 50% by volume, and still more preferably 15 to 40% by volume based on the total volume of the film.
The average diameter of the pores in the film is preferably 20 nm or less, more preferably 10 nm or less, more preferably 5 nm or less, more preferably 2 nm or less, and particularly preferably 1 nm or less.
The average diameter of the holes is a value measured with an X-ray scattering measurement device.

<Supercritical medium processing>
The insulating film of the present invention is a low dielectric constant interlayer insulating film obtained by performing the above-described treatment to obtain the film and then treating it with a supercritical medium containing a pore sealant.
By using a supercritical medium, the pore-forming agent remaining in the film is removed, and at the same time, a pore seal additive that is difficult to gasify at an extremely low temperature of 300 ° C. or lower is uniformly diffused and reacted in the film. be able to.

  Examples of supercritical media include carbon dioxide, oxygen, argon, krypton, xenon, ammonia, methane, ethane, methanol, ethanol, isopropanol, dimethyl ketone, sulfur hexafluoride, carbon monoxide, dinitrogen monoxide, forming gas, Hydrogen and mixtures of two or more thereof can be used. Among these, carbon dioxide is preferable.

For example, when the supercritical medium is carbon dioxide, the critical point (the point at which it becomes a supercritical state) is a temperature of 31.0 ° C. and a pressure of 7.38 MPa, and it becomes a supercritical state at a temperature and pressure above this critical point.
As an apparatus used in this case, for example, an apparatus as shown in FIG. 1 can be used.

The apparatus shown in FIG. 1 will be described.
The apparatus used for the supercritical medium processing of FIG. 1 has a holding table 12 in which a heater 12A is embedded, which holds a substrate W to be processed (a substrate having a film obtained by the above-described processing). A processing container 11 is provided. A medium supply unit 13 for supplying a processing medium is connected to the processing container 11 via a medium supply path 15. The medium supply unit 13 is filled with a medium in which a pore sealant is dissolved in a fluid in a supercritical state (hereinafter, this fluid is referred to as a processing medium), and the processing medium is supplied by temperature control means 14 provided in the medium supply unit. Temperature controlled. The temperature control means 14 has a metallic casing having high thermal conductivity, and a heat exchange channel 14a is formed inside the casing and is connected to the circulation device 23 via the introduction path 14A and the discharge path 14B. Has been. The circulation device 23 has a cooling mechanism and a heating mechanism installed therein, and controls the temperature of the medium by heating or cooling the medium inside the medium supply unit 13 via a heat exchange fluid as necessary. . A line 18 with a valve 18 </ b> A is connected to the medium supply unit 13, and a fluid in which a pore sealant is dissolved is introduced from the line 18. When introducing the pore sealant into the medium supply unit 13, for example, the process medium is introduced by opening the valve 18A from the introduction path 18 in a state (process medium) in which the pore sealant is dissolved in the supercritical medium. To do. The line 18 is connected to a CO ₂ supply source, a compression (pressure increase) means, and a mixing means of a pore sealant and CO ₂ , and a processing medium is supplied from the line 18 to the medium supply unit 13 and filled. In order to set CO ₂ inside the medium supply unit 13 in a supercritical state in advance, for example, before supplying the processing medium from the line 18 to the medium supply unit 13, the medium supply unit 13 is supplied with CO supplied from the line 19. _The method of pressurizing with ₂ may be taken. Further, the inside of the medium supply unit 13 can be purged using CO ₂ supplied from the line 18. The processing medium filled in the medium supply unit 13 is introduced into the processing container 11 from the medium supply path 15 through the supply port 11A of the processing container 11 by opening the valve 15A.

A holding table 12 that holds the substrate to be processed W is installed in the processing container 11, and the wafer held on the holding table 12 is heated by the heater 12 </ b> A. The processing medium supplied to the processing container 11 is discharged from the discharge port 11B, and is returned to the medium supply unit 13 through the medium reflux path 16 connected to the discharge port 11B.
The medium reflux path 16 is provided with a valve 16A, and the processing medium supplied to the processing container 11 is refluxed to the medium supply unit 13 by opening the valve 16A. In the medium supply unit 13, the refluxed processing medium is cooled by the temperature control unit 14 and supplied again from the medium supply path 15 to the processing container 11.

  In order to control the temperature of the inner wall of the processing container 11, a circulation device 21 is connected as temperature control means. The circulation device 21 is connected to a heat exchange flow path formed inside the processing container 11 via an introduction path 21A and a discharge path 11B.

Further, a line 17 with a valve 17A is connected to the processing container 11, and a CO ₂ supply source and a compression means are connected to the line 17, for example, before introducing a processing medium into the processing container 11. In addition, by opening the valve 17A and introducing CO ₂ into the processing container 11, the pressure in the processing container 11 can be increased. Further, for example, after the processing with the supercritical medium is completed, the inside of the processing container 11 can be purged using CO ₂ in a supercritical state. A medium discharge path 20 with a back pressure valve (holding pressure valve) 20A is connected to the medium reflux path 16, and the back pressure valve 20A is opened so that after the film formation process is completed, the processing container 11 and the medium supply are completed. It is possible to discharge the processing medium and by-products remaining in the section 11. As for the opening degree of the back pressure valve 20A, the pressure measured by the pressure gauge 16C installed in the medium reflux path 16 is fed back to the control means 16D, and the control means 16D adjusts the opening degree of the back pressure valve 20A. If necessary, the pressure in the reflux path 16, the processing vessel 11, or the medium supply unit 13 is adjusted to exhaust the processing medium, or the processing medium is in a supercritical state. When purging with a medium, the pressure is adjusted so that the medium to be purged or the processing medium is in a supercritical state.

  Processing using a supercritical medium can be performed using such an apparatus.

  The conditions for treating the film in which the pores are formed in the supercritical medium are a temperature of 0 to 200 ° C., more preferably 20 to 150 ° C., a pressure of 10 to 200 atm, and more preferably 20 to 180 atm. . The treatment time in the supercritical medium is 10 seconds to 2 hours, more preferably 1 minute to 1 hour.

  In obtaining the insulating film of the present invention, a compound (pore sealant) capable of pore-sealing with respect to pores extracted and formed by the supercritical medium is added to the supercritical medium. The pore sealant has the effect of preventing moisture from entering by adsorbing and reacting with the active sites such as the pores and the radicals and hydroxyl groups of the pores formed when the pore-forming agent is discharged out of the film. It is a substance that you have.

The pore sealant is preferably a silane compound. This is because the effect of preventing the entry of moisture as described above is high.
The pore sealants that are silane compounds are tetramethylcyclotetrasiloxane (TMCTS), hexamethyldisilazane (HMDS), tetramethyldisilazane (TMDS), trimethylsilyidimethylamine (TMSDMA), trimethylsilyldiethylamine (TMSDEA), N-trimethylsilyl-imidazole (TMSI), methyltrimethoxysilane (MTMOS), and vinyltrimethoxysilane (MTMOS), MOS ), trimethylchlorosilane (TMCS), dimethylsilyidimethylamine (DMSDMA), dimethylsilyldiethylamine (DMSDEA), bis (dimethylamino) methyl silane (B [DMA] MS), bis (dimethylamino) dimethyl silane (B [DMA] DS), dimethylaminopentamethyldisilane (DMAPMDS), dimethylaminodimethyldisilane (DMADMDS), disila-aza-cyclopentane (TDACP), disila-oza-cyclopentane (TDOCP), triethylchlorosilane (TECS), tetramethoxysilane (TMOS), dimethyldimethoxysilane (DMDMOS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTEOS), dimethyldiethoxysilane ( DMDEOS), vinyltriethoxysilane (VTEOS), trimethylmethoxysilane (TMMS), trimethylethoxysilane (TMES), trimethylsilanol (TMS-OH), bis (trimethoxysilyl) hexane , bis (trimethoxysilyl) octane, bis (trimethylsilylmethyl) dimethoxysilane, bistrimethoxysilylethane, cyclohexylmethyldimethoxysilane, cyclohexyltrimethoxysilane, dicyclopentyldimethoxysilane, diisobutyldimethoxysilane, diisopropyldimethoxysilane, dimethyldimethoxysilane, hexadecyltrimethoxysilane, octyldimethylmethoxysilane, trimethoxysilane, trimethylmethoxysilane, trisilane Of these, TMCTS is preferable.

  The content of the pore sealant in the supercritical medium is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass, and still more preferably 0.5 to 1.5% by mass.

  When a compound capable of pore sealing is added to the supercritical medium, carbon dioxide or the like as a supercritical medium may be introduced after introducing a desired amount of additive into the processing vessel, and pressurization may be started. You may inject | pour into the medium of a critical state.

The low dielectric constant interlayer insulating film obtained by the method described above is the insulating film of the present invention. In addition, a substrate with an insulating film, which is a substrate having the insulating film of the present invention, can be obtained by such a method.
The insulating film of the present invention is suitable as an insulating film in electronic parts such as semiconductor devices and multichip module multilayer wiring boards. In addition to an interlayer insulating film for semiconductors, a surface protective film, and a buffer coat film, a passivation film in LSI, α It can be used as a line blocking film, a flexographic printing plate cover lay film, an overcoat film, a flexible copper clad cover coat, a solder resist film, a liquid crystal alignment film, and the like.
As another application, the insulating film of the present invention can be used as a conductive film by imparting conductivity by doping with an electron donor or acceptor.

Moreover, this invention is a manufacturing method of the board | substrate (board | substrate with an insulating film) which has an insulating film of this invention. That is, the present invention applies a film-forming composition containing an organic compound and a pore-forming agent on a substrate to form a film on the substrate, cures the film, and then coats the film with a pore sealant. Is a method for manufacturing a substrate with an insulating film, wherein a substrate having a low dielectric constant interlayer insulating film is obtained.
That is, the process for obtaining the insulating film of the present invention described above is the method for manufacturing a substrate with an insulating film of the present invention.

  The following examples illustrate the invention and are not intended to limit its scope.

[Example A: Film-forming composition containing a cage structure type compound and a pore-forming agent]

<Synthesis Example 1>
4,9-dibromodiadamantane was synthesized by the method described in Macromolecules., 24, 5266 (1991). Next, 1.30 g of commercially available p-divinylbenzene, 3.46 g of 4,9-dibromodiadamantane, 200 ml of dichloroethane, and 2.66 g of aluminum chloride were charged into a 500 ml flask and stirred at an internal temperature of 70 ° C. for 24 hours. Thereafter, 200 ml of water was added to separate the organic layer. After adding anhydrous sodium sulfate, the solid content was removed by filtration, and dichloroethane was concentrated under reduced pressure until the volume was reduced to half, 300 ml of methanol was added to this solution, and the deposited precipitate was filtered. In this way, 2.8 g of the polymer shown as (A-4) above having a weight average molecular weight of 10,000 was obtained.

<Example 1>
1.0 g of the above polymer and 0.2 g of anionically polymerized polystyrene (Mn: 8200) were dissolved by heating in a mixed solvent of 5.0 ml of cyclohexanone and 5.0 ml of anisole to prepare a coating solution. The solution was filtered through a 0.1 micron tetrafluoroethylene filter, spin-coated on a silicon wafer, and the film was heated on a hot plate at 150 ° C. for 60 seconds under a nitrogen stream. The film thickness of the obtained film was measured with a reflection interference type film thickness meter and found to be 0.5 microns. The average pore diameter based on visual inspection of the film by TEM observation was 4 nm.

(Supercritical medium processing)
The obtained film-coated substrate was placed in a sealed chamber made of zirconium shown in FIG. 1 and treated with a supercritical medium under the following conditions.
TMCTS was dropped into the chamber so as to be 1% by volume in a standard state with respect to the volume in the sealed chamber. Thereafter, carbon dioxide was introduced into the chamber and heated to 140 atm. Thereafter, the temperature was gradually increased at 5 ° C./min, and the chamber was heated to 100 ° C. This state was maintained for 5 minutes. After allowing the chamber to cool to room temperature, the chamber was returned to atmospheric pressure and the substrate was taken out. When the relative dielectric constant of the film on the obtained substrate was measured with a mercury probe, it was 2.15, and it was again measured after being left in an environment of temperature 23 ° C. and humidity 45% RH for 2 weeks. The dielectric constant was 2.19.

<Comparative Example 1>
The dielectric constant was 2.16 when evaluated in the same manner as in Example 1 except that the treatment with the supercritical medium was not performed. The re-measurement after 2 weeks was 2.7.

<Comparative example 2>
The dielectric constant was 2.14 when evaluated in the same manner as in Example 1 except that TMCTS was not added to the medium. The remeasurement after 2 weeks was 2.65.

FIG. 1 is a schematic explanatory diagram of a supercritical medium processing apparatus that can be suitably used for obtaining an insulating film of the present invention.

Explanation of symbols

11 Processing container 12 Holding table 12A Heating means (heater)
13 Medium supply section 14 Temperature control means 14a Heat exchange flow path 15 Medium supply path 16 Medium return path 17, 18, 19 line (introduction path)
21, 23 Circulator 15A, 16A, 17A, 18A Valve 20A Back pressure valve 11A, 14A, 21A Supply path (introduction path)
11B, 14B, 21B Discharge path 16C Pressure gauge 16D Control mechanism

Claims (4)

  A film-forming composition containing an organic compound and a pore-forming agent is applied onto a substrate to form a film on the substrate, the film is cured, and then the film is coated with a supercritical medium containing a pore sealant. Low dielectric constant interlayer insulating film obtained by processing.   The low dielectric constant interlayer insulating film according to claim 1, wherein the pore sealant is a silane compound.   The board | substrate with an insulating film which has the low dielectric constant interlayer insulation film of Claim 1 or 2 on the said board | substrate.   A film-forming composition containing an organic compound and a pore-forming agent is applied onto a substrate to form a film on the substrate, the film is cured, and then the film is coated with a supercritical medium containing a pore sealant. A method of manufacturing a substrate with an insulating film, which is processed to obtain a substrate having a low dielectric constant interlayer insulating film.

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