JP2001294815A - Aqueous dispersion for forming low-dielectric constant insulation film, the resultant low-dielectric constant insulation film, and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous dispersion for forming a low dielectric constant insulator film capable of forming organic insulation film by electrodeposition, to provide the low-dielectric constant insulation film obtained from the above aqueous dispersion, and to provide electronic components each having the above low-dielectric constant insulation film. SOLUTION: This aqueous dispersion for forming a low-dielectric constant insulation film is such that film-nonforming microparticles <=1 μm in average size and <=3 in dielectric constant and organic particles consisting of a polymerizable compound and/or a polymer are dispersed in an aqueous medium, and is characterized by being capable of forming insulation film by electrodeposition; wherein the film-nonforming microparticles are preferably fluorine-containing microparticles and/or crosslinked organic microparticles, and the organic particles preferably have electric charge on the surface and consist of a polyimide-based resin. The 2nd objective low-dielectric constant insulation film to be formed the above aqueous dispersion by electrodeposition is characterized by being <=3 in dielectric constant. The other objective electronic components are characterized by being provided respectively with the above low- dielectric constant insulation films.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous dispersion for forming a low dielectric constant insulating film which forms an insulating film by electrodeposition, a low dielectric constant insulating film formed from the aqueous dispersion, and a low dielectric constant insulating film. The present invention relates to an electronic component having a film.

[0002]

2. Description of the Related Art With an increase in the degree of integration of semiconductor integrated circuits and the like in electronic components and an increase in element density, there is an increasing demand for multilayer semiconductor devices. In a multilayer wiring of a semiconductor integrated circuit, a signal propagation speed is determined by a wiring resistance and a parasitic capacitance between wirings. Due to the high integration of devices, wiring widths and wiring intervals are becoming narrower, so that wiring resistance is increasing and parasitic capacitance between wirings is increasing. The capacitance of the insulating film can be reduced by reducing the wiring thickness and cross-sectional area, but
If the wiring thickness is reduced, the wiring resistance is further increased. Therefore, in order to increase the speed, it is necessary to reduce the resistance of the wiring and the dielectric constant of the insulating film, and these are expected to be major factors that govern the performance of the device.

Conventionally, as a low dielectric constant insulating film used for a semiconductor integrated circuit or the like, an inorganic material such as silicon dioxide (SiO ₂ ) or an organic polymer material such as polyimide has been used. In addition to these, SiOF materials and SiO ₂ -based resins containing Si—H have been studied as inorganic materials having a low dielectric constant, and fluorine-containing resin materials and the like have been known as organic materials. A low dielectric constant insulating film made of an organic polymer material has a feature that, unlike a film made of an inorganic material such as SiO ₂ , a wiring material generally does not easily diffuse. However, a sufficiently low dielectric constant may not be achieved with a conventional insulating film made of only an organic polymer material such as polyimide. In addition, since the fluorine-containing resin material has low adhesion to other materials, there is a problem that when an insulating film is formed from this material, voids are generated beside wiring. Furthermore, as a film forming method for obtaining an insulating film from an organic polymer material, a method by applying and drying a solution is mainly used,
With this coating method, it is difficult to increase the film thickness accuracy.
In addition, it is difficult to say that the operability is good when the insulating film is formed only at a specific position on the substrate.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous dispersion for forming an organic insulating film by electrodeposition and a low dielectric constant insulating film obtained from the aqueous dispersion. And an electronic component having the low dielectric constant insulating film.

[0005]

Means for Solving the Problems The present inventors have prepared an aqueous dispersion for forming a low dielectric constant insulating film in which electrodepositable organic particles and low dielectric constant non-film-forming fine particles are dispersed in an aqueous medium. The present inventors have found that the above problems can be solved by using the present invention, and have completed the present invention.

That is, the aqueous dispersion for forming a low dielectric constant insulating film according to the first aspect has a mean particle diameter of 1 μm in an aqueous medium.
Non-film-forming fine particles having a relative dielectric constant of 3 or less and organic particles comprising at least one of a polymerizable compound and a polymer are dispersed, and an insulating film can be formed by electrodeposition. . As the non-film-forming fine particles, at least one selected from fluorine-containing fine particles and crosslinked organic fine particles is preferably used. Further, it is preferable that the organic particles have a charge on the particle surface and are made of a polyimide resin.

A low dielectric constant insulating film according to a fourth aspect is formed by electrodeposition using the aqueous dispersion for forming a low dielectric constant insulating film according to any one of the first to third aspects, and has a specific dielectric constant. 3 or less.

According to a fifth aspect of the present invention, there is provided an electronic component comprising a low dielectric constant insulating film formed by electrodeposition using the aqueous dispersion for forming a low dielectric constant insulating film according to any one of the first to third aspects. It is characterized by the following. Hereinafter, the present invention will be described in more detail.

(1) Non-Film-forming Fine Particles The average particle diameter of the “non-film-forming fine particles” used in the present invention is 1 μm or less, preferably 0.7 μm or less, more preferably 0.5 μm or less. . Average particle size is 1
If it exceeds μm, the dispersibility of the non-film-forming fine particles in the aqueous medium will be insufficient, and sufficient storage stability will not be obtained. The lower limit of the average particle diameter is not particularly limited, but is usually 0.02 μm or more. The relative permittivity of the non-film-forming fine particles is 3 or less, more preferably 2.8 or less,
More preferably, it is 2.6 or less. When non-film-forming fine particles having a relative dielectric constant of more than 3 are used, a large amount of the organic particles is required for the insulating film formed from the aqueous dispersion of the present invention to have a sufficiently low dielectric constant. Since non-film-forming fine particles are used, the strength, adhesion, and the like of the insulating film are reduced, and further, film-forming properties are insufficient. In this specification, “non-film-forming property” means that a continuous film is not formed when the medium is removed at a temperature of 150 ° C. or lower.

The material is not particularly limited as long as it is a non-film-forming fine particle satisfying the above average particle diameter and relative dielectric constant. Usually, non-film-forming fine particles made of an organic material are preferably used, and it is more preferable to use at least one kind of fine particles selected from fluorine-containing fine particles and crosslinked organic fine particles. Hereinafter, the fluorine-containing fine particles and the crosslinked organic fine particles will be further described.

[Fluorine-containing organic fine particles] Examples of the fluorine-containing organic fine particles used in the present invention include polytetrafluoroethylene (PTFE) and tetrafluoroethylene-
Fine particles composed of one or more selected from hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA) and the like are exemplified, and PTFE is particularly preferably used. The fluorine-containing organic fine particles may or may not be crosslinked.

[Crosslinked Organic Fine Particles] The crosslinked organic fine particles used in the present invention are not particularly limited. For example, crosslinkable monomers such as benzoguanamine and divinylbenzene (hereinafter, also referred to as “monomer a”) ), And fine particles comprising a copolymer of monomer a and another monomer copolymerizable with monomer a (hereinafter, also referred to as “monomer b”). . The preferred ratio of the monomer a to the monomer b is as follows: monomer a (% by weight) / monomer b (% by weight) = 5 to 100/0 to 95;
To 100/0 to 80, more preferably 40 to 10
0 / 0-60. Preferred examples of the monomer b include aromatic vinyl compounds such as styrene and α-methylstyrene, methyl methacrylate, and 3- (perfluoro-5).
(Meth) acrylic acid esters such as -methylhexyl) -2-hydroxypropyl methacrylate.

Preferred crosslinked organic fine particles comprising a polymer obtained by using monomer a as an essential component include monomer a
A homopolymer of, a monomer a, a copolymer of a monomer b having an aromatic vinyl compound as an essential component, a monomer a,
Monomer b containing (meth) acrylate as an essential component
And a copolymer of a monomer a with a monomer b containing an aromatic vinyl compound and a (meth) acrylate ester as essential components.

The crosslinked organic fine particles are hollow crosslinked organic fine particles (hereinafter referred to as "hollow polymer fine particles").
May be used. The average particle diameter of the hollow polymer fine particles is preferably from 0.05 to 1 μm, more preferably from 0.1 to 0.5 μm. The inner diameter of the hollow polymer particles is preferably 0.1 to 0.9 times the outer diameter, more preferably 0.2 to 0.9 times, particularly preferably 0.3 to 0.9 times.
0.9 times. The average specific gravity of the hollow polymer fine particles is preferably 0.5 to 1.2, and more preferably 0.5 to 1.2.
6 to 1.1. Average particle diameter of hollow polymer fine particles,
When the ratio between the inner diameter and the outer diameter and the average specific gravity are within the above ranges, an insulating film having a low dielectric constant can be formed from the dispersion of the present invention containing the hollow polymer fine particles. In addition,
As the non-film-forming fine particles of the present invention, non-crosslinked hollow organic fine particles can also be used.

The hollow polymer fine particles may be, for example, (I)
A method in which a foaming agent is contained in the crosslinked polymer particles and then the foaming agent is foamed; (II) a method in which a volatile substance such as butane is encapsulated in the crosslinked polymer, and a method in which the volatile substance is gasified later; (III) A method in which a crosslinked polymer is melted, and a gas jet such as air is blown into the polymer to enclose air bubbles, (IV)
A method in which an alkali-swellable substance is permeated into crosslinked polymer particles or non-crosslinked particles to swell the alkali-swellable substance, (V) a method of preparing an oil-in-water type monomer emulsion and performing polymerization, (VI) A method of suspending a pigment in an unsaturated polyester solution and polymerizing a monomer in the solution, (VII) using a crosslinkable polymer particle as a seed,
A two-step cross-linking method in which a polymer incompatible with the cross-linkable polymer is polymerized and cross-linked on the seed, and (VIII) a method of producing the polymer by polymerizing shrinkage. (IX) It can be produced by various methods such as a method of spray-drying the crosslinkable polymer particles (see Japanese Patent Publication No. 4-68324).

Of the above methods, the method (VII) is preferred. In carrying out the method (VII), it is extremely preferred to carry out the method in the following manner. That is, (a) 1 to 50% by weight of a crosslinkable monomer, and (b) 1 to 40% of an unsaturated carboxylic acid.
% By weight and / or other hydrophilic monomers 5 to 99
1 to 99% by weight of a hydrophilic monomer (hereinafter referred to as "(b) hydrophilic monomer") composed of 1% by weight, and (c)
Other polymerizable monomers that can be copolymerized (hereinafter referred to as “(c)
Other polymerizable monomers ". ) 0-85% by weight of a polymerizable monomer component consisting of 100 parts by weight of a polymer different from the polymerized polymer of the polymerizable monomer component (hereinafter, referred to as a polymer
It is called "heterogeneous polymer". ) Is the seed polymer 1
This is a method of dispersing in water in the presence of 100 parts by weight and then polymerizing the polymerizable monomer component (see JP-A-62-227336).

The hollow polymer fine particles obtained in the above embodiment are used as a seed polymer, and at least one selected from (a) a crosslinkable monomer, (b) a hydrophilic monomer and (c) another polymerizable monomer is used as a seed polymer. By polymerizing, the hollow polymer fine particles used in the present invention can be produced (see JP-A-2-140271 and JP-A-2-140272).

As the crosslinkable monomer (a), divinylbenzene, ethylene glycol dimethacrylate,
Examples thereof include divinyl monomers such as 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate, and trivinyl monomers. Particularly, divinylbenzene, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate are exemplified. preferable. Examples of the hydrophilic monomer (b) include vinylpyridine, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, N-methylol acrylamide, N-methylol methacrylamide, acrylic acid, methacrylic acid, itaconic acid, and fumaric acid. Acid, sodium styrene sulfonate, vinyl acetate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2
Vinyl monomers such as -hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate. Of these, methacrylic acid, itaconic acid and acrylic acid are preferred. The other polymerizable monomer (c) is not particularly limited as long as it has radical polymerizability, and aromatic vinyl monomers such as styrene, α-methylstyrene, p-methylstyrene, and halogenated styrene;
Vinyl esters such as vinyl propionate; ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, 3- (perfluoro-5-methylhexyl) -2-hydroxypropyl Examples thereof include ethylenically unsaturated carboxylic acid alkyl esters such as methacrylate; maleimide compounds such as phenylmaleimide and cyclohexylmaleimide; conjugated diolefins such as butadiene and isoprene; and styrene is particularly preferred.

The different polymer is a polymer different from a polymer obtained by polymerizing at least the polymerizable monomers (a) to (c). Here, "different" means
This is a broad concept including a case where the type of the polymerization monomer is different, a case where the molecular weight is different even when the copolymerization monomer is the same, and a case where the copolymerization ratio is different even when the copolymerization monomer is the same. Specific examples of such heteropolymers include polystyrene, carboxy-modified polystyrene, carboxy-modified styrene-butadiene copolymer, styrene-butadiene copolymer, styrene-acrylester copolymer, styrene-methacrylester copolymer, styrene-acrylester copolymer, and methacrylester. Copolymers, carboxy-modified (styrene-acrylic ester) copolymers, carboxy-modified (styrene-methacrylic ester) copolymers and the like are exemplified. Particularly preferred heterogeneous polymers are polystyrene and styrene copolymers containing at least 50% by weight of a styrene component.

(2) Organic Particles (2-1) Composition of Organic Particles The organic particles used in the present invention are composed of "at least one of a polymerizable compound and a polymer". Here, the "polymerizable compound" refers to a compound having a polymerizable group, and is meant to include a precursor polymer, a polymerizable oligomer, a monomer, and the like before complete curing. On the other hand, “polymer” refers to a compound in which the polymerization reaction has been substantially completed. However, it is also possible to crosslink this polymer after electrodeposition by heating, moisture or the like. The surface of the organic particles preferably has a charge to enable electrodeposition, and the surface charge may be an anion type or a cation type, but should be of a cation type to prevent electrode oxidation during electrodeposition. Is preferred.

The organic particles are preferably made of one or more selected from a polyimide resin, an epoxy resin, an acrylic resin, a polyester resin, a fluorine resin and a silicon resin. Further, other components may be further contained in addition to these resins. Further, these resins may be chemically bonded to each other or other components.

In the present invention, it is particularly preferable to use organic particles containing a polyimide resin as a main component, since a low dielectric constant insulating film having excellent mechanical, chemical and electrical properties can be formed by electrodeposition. preferable. here,
"Polyimide resin" refers to a polyimide resin or a precursor polymer (for example, polyamic acid or the like) curable by heating or the like after electrodeposition, a monomer used for forming the polyimide resin, and another monomer. Of the copolymer resin or a precursor polymer thereof, a polyimide resin or a reaction product of the precursor polymer and another compound, and further includes a monomer and an oligomer used for forming a polyimide resin. The same applies to other resins.

(2-2) Aqueous Emulsion of Organic Particles The aqueous dispersion of the present invention is usually prepared using an aqueous emulsion in which the organic particles are dispersed in an aqueous medium. Here, the “aqueous medium” means a medium containing water as a main component, and the content of water in the aqueous medium is usually 40% by weight or more,
It is preferably at least 50% by weight. Other media optionally used with water include the aprotic polar solvents, esters, ketones, phenols, alcohols and the like used in the production of the polyamic acid or polyimide.

Hereinafter, an aqueous emulsion of organic particles mainly composed of a polyimide resin (hereinafter referred to as "polyimide resin emulsion"), and an aqueous emulsion of particles mainly composed of epoxy resin (hereinafter referred to as "epoxy resin emulsion"). ), An aqueous emulsion of particles mainly composed of an acrylic resin (hereinafter, referred to as “acrylic resin emulsion”), and an aqueous emulsion of particles mainly composed of a polyester resin (hereinafter, referred to as “acrylic resin emulsion”).
It is called “polyester resin emulsion”. ), An aqueous emulsion of particles mainly composed of a fluororesin (hereinafter referred to as “fluorine resin emulsion”) and an aqueous emulsion of particles mainly composed of a silicon resin (hereinafter referred to as “silicone resin emulsion”). Will be described.

(I) Method for Producing Polyimide Resin Emulsion When the organic particles in the present invention are made of a polyimide resin, a polyimide-based low dielectric constant insulating film having excellent mechanical, chemical and electrical properties. This is particularly preferred because it can form The following two types are preferred as methods for producing such a polyimide-based insulating film by electrodeposition. A method in which a polyimide resin emulsion composed of composite particles of (A) an organic solvent-soluble polyimide and (B) a hydrophilic polymer is used as an electrodeposition liquid, and the composite particles are electrodeposited. A method in which a polyimide resin emulsion composed of particles containing composite particles of (C) a polyamic acid and (D) a hydrophobic compound is used as an electrodeposition liquid and the particles are electrodeposited, and the electrodeposited polyamic acid is dehydrated and closed by heating. . As a method for producing a polyimide resin emulsion used in these methods, the method described in JP-A-11-49951 is used for the above method, and the method described in JP-A-11-60947 is used for the above method. Is exemplified.

The method for producing the polyimide resin emulsion used in the above method will be described in more detail. The synthesis method of “(A) polyimide soluble in an organic solvent” is not particularly limited. For example, in an organic polar solvent,
Polyimide is synthesized by mixing and polycondensing a tetracarboxylic dianhydride and a diamine compound to obtain a polyamic acid, and then subjecting the polyamic acid to a dehydration ring-closing reaction by a heat imidation method or a chemical imidization method. can do. In addition, a polyimide having a block structure can be synthesized by performing polycondensation of a tetracarboxylic dianhydride and a diamine compound in multiple stages. The organic solvent-soluble polyimide includes, for example, a reactive group (a) such as a carboxyl group, an amino group, a hydroxyl group, a sulfonic acid group, an amide group, an epoxy group, and an isocyanate group.
It is preferable to have one or more of these. As a method for synthesizing a polyimide having a reactive group (a), for example, a reactive raw material such as a carboxylic dianhydride, a diamine compound, a carboxylic monoanhydride, or a monoamine compound used for the synthesis of polyamic acid may be used. Examples of the method include using a compound having the group (a) and leaving the reactive group (a) after the dehydration ring closure reaction.

The “(B) hydrophilic polymer” has, for example, at least one kind of hydrophilic group such as an amino group, a carboxyl group, a hydroxyl group, a sulfonic acid group and an amide group.
It is composed of a hydrophilic polymer having a solubility at 0 ° C. of usually 0.01 g / 100 g or more, preferably 0.05 g / 100 g or more. In addition to the hydrophilic group, it is preferable to have at least one reactive group (b) capable of reacting with the reactive group (a) in the component (A). Examples of such a reactive group (b) include, in addition to an epoxy group, an isocyanate group, and a carboxyl group, groups similar to the aforementioned hydrophilic groups. Such a hydrophilic polymer is obtained by homopolymerizing or copolymerizing a monovinyl monomer having a hydrophilic group and / or a reactive group (b), or combining these monovinyl monomers with other monomers. It can be obtained by copolymerization.

This (A) organic solvent-soluble polyimide and (B) a hydrophilic polymer are combined with a combination in which the reactive group (a) and the reactive group (b) in the hydrophilic polymer have appropriate reactivity. The polyimide and the hydrophilic polymer are mixed in a solution state in, for example, an organic solvent, and heated and reacted as necessary, and then the reaction solution and the aqueous medium are mixed. By mixing and optionally removing at least a part of the organic solvent, the polyimide and the hydrophilic polymer can be mutually bonded to obtain a polyimide resin emulsion composed of composite particles contained in the same particle.

Next, the method for producing the polyimide resin emulsion used in the above method will be described in more detail. The method for synthesizing “(C) polyamic acid”, which is a precursor of polyimide, is not particularly limited. For example, a polyamic acid is obtained by a polycondensation reaction between a tetracarboxylic dianhydride and a diamine compound in an organic polar solvent. An acid can be obtained. In addition, a polyamic acid having a block structure can be synthesized by performing a polycondensation reaction between a tetracarboxylic dianhydride and a diamine compound in multiple stages. Note that a polyamic acid partially imidized by dehydrating and cyclizing the polyamic acid can also be used.

On the other hand, the "(D) hydrophobic compound" is a compound having a group capable of reacting with at least an amic acid group in the polyamic acid (hereinafter referred to as "reactive group"). Examples of the reactive group include an epoxy group, an isocyanato group, a carbodiimide group, a hydroxyl group, a mercapto group, a halogen group, an alkylsulfonyl group, an arylsulfonyl group, a diazo group, and a carbonyl group. One or more of these reactive groups can be present in the hydrophobic compound. The term “hydrophobic” means that the solubility in water at 20 ° C. is generally less than 0.05 g / 100 g, preferably less than 0.01 / 100 g, and more preferably less than 0.005 g / 100 g. .

Examples of such a hydrophobic compound include epoxidized polybutadiene, bisphenol A type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, biphenyl type epoxy resin, glycidyl ester type epoxy resin, allyl glycidyl ether,
Glycidyl (meth) acrylate, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N,
N ', N',-tetraglycidyl-m-xylenediamine, tolylenediisocyanate, dicyclohexylcarbodiimide, polycarbodiimide, cholesterol, benzyl alcohol p-toluenesulfonic acid ester, ethyl chloroacetate, triazinetrithiol, diazomethane, diacetone (meth) One or more selected from acrylamide and the like can be used.

The polyamic acid (C) and the hydrophobic compound (D) are mixed and reacted in an organic solvent, for example, and then the reaction solution is mixed with an aqueous medium.
In some cases, by removing at least a part of the organic solvent, a polyimide resin emulsion composed of composite particles containing a polyamic acid and a hydrophobic compound in the same particle can be obtained.

The tetracarboxylic dianhydride used in the above and the above methods is not particularly limited, and examples thereof include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetraanhydride. Carboxylic dianhydride, 3,3 ′, 4,4′-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,3,3a, 4,5
Aliphatic tetracarboxylic dianhydrides such as 9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione or alicyclic Tetracarboxylic dianhydride; pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfonetetracarboxylic dianhydride Aromatic tetracarboxylic dianhydride; and the like. These tetracarboxylic dianhydrides can be used alone or in combination of two or more.

The diamine compound used in the above method and the above method is not particularly limited.
Examples include p-phenylenediamine, 4,4'-
Diaminodiphenylmethane, 2,2-bis [4- (4-
Aromatic diamines such as [aminophenoxy) phenyl] propane; 1,1-methaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, 4,4′-
Aliphatic diamines such as methylenebis (cyclohexylamine) or alicyclic diamines; 2,3-diaminopyridine, 2,4-diamino-6-dimethylamino-1,
Two primary amino groups and a nitrogen atom other than the primary amino groups in the molecule, such as 3,5-triazine, 2,4-diamino-5-phenylthiazole, bis (4-aminophenyl) phenylamine Diamines having: monosubstituted phenylenediamines; diaminoorganosiloxane;
And the like. These diamine compounds are:
They can be used alone or in combination of two or more.

(Ii) Method for producing epoxy resin emulsion The method for producing the epoxy resin emulsion is not particularly limited, and a conventionally known method, for example, JP-A-9-2
The methods described in JP-A-35495 and JP-A-9-208865 may be used.

(Iii) Method for Producing Acrylic Resin Emulsion A method for producing an acrylic resin emulsion is not particularly limited, but it can be produced, for example, by a usual emulsion polymerization method. As the monomer, one or more kinds selected from general acrylic and / or methacrylic monomers may be used. At this time, a monomer having a cationic group such as an amino group, an amide group or a phosphono group, or a monomer having an anionic group such as a carboxyl group or a sulfonic acid group in order to make the particles electrodepositable. Is preferably copolymerized, and the copolymerization amount is from 5 to 80% by weight (more preferably from 10 to 80% by weight) based on the whole monomers used.
50% by weight). As specific examples of the monomer having an amino group, dimethylaminoethyl acrylate, dimethylaminopropyl acrylamide and the like are preferably used.

(Iv) Method for Producing Polyester Resin Emulsion The method for producing polyester resin emulsion is not particularly limited.
The method described in JP-A-7-10663, JP-A-57-70153, and JP-A-58-174421 may be used.

(V) Method for producing a fluorine-based resin emulsion The method for producing a fluorine-based resin emulsion is not particularly limited, and a conventionally known method, for example, JP-A-7-26
The method described in JP-A-8163 may be used.

(Vi) Production Method of Silicone Resin Emulsion The production method of the silicone resin emulsion is not particularly limited.
The method described in Japanese Patent No. 60280 may be used.

(3) Aqueous Dispersion The aqueous dispersion of the present invention is obtained by dispersing the organic particles and the non-film-forming fine particles in an aqueous medium. The meaning of the aqueous medium is as described above. The weight ratio between the non-film-forming fine particles and the organic particles contained in the aqueous dispersion is 5/95.
~ 98/2, preferably 10/90 ~
80/20, more preferably 20 / 80-6.
More preferably, it is 0/40. If the proportion of the non-film-forming fine particles is less than 5% by weight, it is difficult to obtain a low dielectric constant insulating film. On the other hand, when the proportion of the non-film-forming fine particles exceeds 98% by weight, the film-forming properties become insufficient, which is not preferable. The preferred pH of the aqueous dispersion is 2 to 10 (more preferably 3 to 9), and the preferred solid concentration is 1 to 50% by weight.
(More preferably 5 to 20% by weight), and a preferable viscosity at 20 ° C is 1 to 100 mPa · s. If the pH, the solid content concentration or the viscosity is out of the above-mentioned range, the dispersibility of the particles and the like may be reduced, and the storage stability may be insufficient, or the workability during handling and use may be reduced.

This aqueous dispersion can be prepared by a method such as mixing the non-film-forming fine particle dispersion and the organic particle dispersion, or adding and mixing the non-film-forming fine particles into the organic particle dispersion. . It is preferable to use one of these methods. Further, the pH of the non-film-forming fine particle dispersion before mixing with the organic particle dispersion is adjusted to a pH of 2 to 3 using nitric acid, sulfuric acid, acetic acid, ammonia, potassium hydroxide, or the like in order to improve the stability during mixing. Preferably, it is adjusted to 10. When the non-film-forming fine particles are hydrophobic, the non-film-forming fine particles may be dispersed in an amphipathic solvent such as alcohol, and then mixed with the organic particle dispersion. The aqueous dispersion of the present invention has a storable period at 20 ° C. of 5 days or more (more preferably 7 days or more, further preferably 10 days or more, particularly preferably 10 days or more) without causing two-layer separation or significant change in viscosity. 14 days or more).

The aqueous dispersion of the present invention contains, in addition to the non-film-forming fine particles and the organic particles, an organosilane represented by the following formula (1), and a part of the hydrolyzable group of the organosilane. Alternatively, the hydrolyzate may contain at least one selected from a hydrolyzate that is completely hydrolyzed and a partial condensate obtained by partially dehydrating and condensing this hydrolyzate (hereinafter, referred to as “organosilane condensate”). . The insulating film formed from such an aqueous dispersion, particularly when heat-cured after electrodeposition, by crosslinking organosilane condensate and the like in the insulating film, mechanical properties, chemical properties hardness and It has excellent electrical characteristics.

[0043]

(R ¹ ) _n Si (OR ² ) _4-n (1) (wherein, R ¹ represents a hydrogen atom or a monovalent organic group having 1 to 8 carbon atoms, and R ² represents 1 carbon atom. Represents an alkyl group of 5 to 5, an acyl group of 1 to 6 carbon atoms or a phenyl group, and n is an integer of 1 or 2. R ¹ and R ² may be the same or different. )

In the above formula (1), R ¹ has 1 to ¹ carbon atoms.
Examples of the organic group 8 include a linear or branched alkyl group, a halogen-substituted alkyl group, a vinyl group, a phenyl group, and a 3,4-epoxycyclohexylethyl group. Note that R ¹ may have a carbonyl group. R ¹ is preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group. Examples of the alkyl group having 1 to 5 carbon atoms or the acyl group having 1 to 6 carbon atoms of R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, Examples thereof include a tert-butyl group, an n-pentyl group, an acetyl group, a propionyl group, and a butyryl group. R ² is preferably an alkyl group having 1 to 4 carbon atoms.

Examples of preferably used organosilanes include dimethyldimethoxysilane, dimethyldiethoxysilane, isobutyltrimethoxysilane and phenyltriethoxysilane. One of these organosilanes may be used alone, or two or more thereof may be used in combination.

The “organosilane condensate and the like” preferably forms composite particles with the organic particles in the aqueous dispersion of the present invention. This `` composite particle '' refers to a compound in which the compound constituting the organic particles is chemically bonded to an organosilane condensate or the like, or a compound in which an organosilane condensate or the like is adsorbed on the surface or inside of the organic particles. Point. The amount of the organosilane condensate to be used is preferably 0.1 to 500 parts by weight, more preferably 0.5 to 250 parts by weight, based on 100 parts by weight of the organic particles. If the amount of the organosilane condensate or the like is less than 0.1 part by weight, the desired effect may not be obtained. On the other hand, if it exceeds 500 parts by weight, the adhesiveness of the insulating film tends to decrease.

Such composite particles can be produced by the following method [1] or [2]. Note that these methods may be combined. [1] After the organosilane is added to the emulsion of the organic particles and at least a part of the organosilane is absorbed by the organic particles, a hydrolysis reaction and a condensation reaction of the organosilane are allowed to proceed. [2] A reaction for generating the organic particles is performed in the presence of the organosilane condensate or the like dispersed in an aqueous medium.

In the method [1], the organosilane can be absorbed by the organic particles by a method such as adding the organosilane to the emulsion and sufficiently stirring the emulsion. At this time, 10% by weight of the added organosilane was used.
It is preferable that the particles absorb more than the above (more preferably 30% by weight). In order to prevent the hydrolysis / condensation reaction of the organosilane from proceeding at the stage where the absorption is insufficient, the pH of the reaction system is usually 4 to 10, preferably 5 to 1.
0, more preferably 6 to 8.
The treatment temperature for absorbing the organosilane into the organic particles is preferably 70 ° C. or lower, more preferably 5 ° C.
The temperature is 0 ° C or lower, more preferably 0 to 30 ° C. The processing time is usually 5 to 180 minutes, and preferably about 20 to 60 minutes. The temperature at which the absorbed organosilane is hydrolyzed and condensed is usually 30 ° C or higher, preferably 50 to 100 ° C, more preferably 70 to 90 ° C,
The preferred polymerization time is 0.3 to 15 hours, more preferably 1 to 8 hours.

In the above method [2], the organosilane is mixed in an aqueous solution of a strongly acidic emulsifier such as alkylbenzenesulfonic acid using a homomixer or an ultrasonic mixer, and the mixture is subjected to hydrolysis and condensation. By doing so, an organosilane condensate or the like dispersed in an aqueous medium is obtained. In the presence of the organosilane condensate or the like, the organic particles may be formed preferably by emulsion polymerization.

(4) Low Dielectric Constant Insulating Film The aqueous dispersion of the present invention may be used as it is or by diluting or concentrating the same, and optionally blending conventionally known additives as necessary. It is used for an electrodeposition liquid for forming an insulating film. By a normal electrodeposition method using this electrodeposition liquid, the non-film-forming fine particles and the organic particles in the aqueous dispersion can be electrodeposited on the electrode surface or the like to produce a low dielectric constant insulating film. In producing the low dielectric constant insulating film of the present invention, it is preferable that the electrodeposited organic particles be further cured by heating. The conditions of the heat curing are not particularly limited, but a preferable heating temperature is 100 ° C to 400 ° C,
More preferably, it is 150 to 300 ° C. Further, the preferable heating time is 5 minutes or more, and more preferably 10 minutes or more.

According to the aqueous dispersion of the present invention, the relative dielectric constant is 3
A low dielectric constant insulating film having the following dielectric constant (more preferably 1.8 to 3, more preferably 1.9 to 2.9) can be obtained. The volume resistivity is 10 ¹² Ω · cm or more (more preferably 10 ¹³ Ω · cm or more, more preferably 10 ¹⁵ Ω · cm or more), and the surface resistivity is 10 ¹² Ω or more (more preferably 10 ¹³ Ω or more). , More preferably 10
¹⁵ Ω or more). The thickness of the low dielectric constant insulating film is 50 μm or less (more preferably, 30 μm or less).
μm or less). The lower limit of the thickness of the insulating film is not particularly limited, but is usually 1 μm or more.

(5) Electronic Components The low dielectric constant insulating film formed from the aqueous dispersion of the present invention is:
Printed circuit boards, semiconductor packages, chip coils,
It can be used for electronic components such as high frequency antennas.
The electronic component or the like provided with the low dielectric constant insulating film can be small in size and high in density.

[0053]

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following, “parts” and “%” are based on weight unless otherwise specified.

(1) Preparation of Organic Particle Emulsion (Synthesis Example 1: Polyimide Resin Emulsion) As a tetracarboxylic dianhydride, 32.29 g of 3,3 ', 4,4'-diphenylsulfonetetracarboxylic dianhydride ( 9
0 mmol) and 1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-
Furanyl) -naphtho [1,2-c] -furan-1,3-
3.00 g (10 mmol) of dione, 36.95 g (90 mmol) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane as a diamine compound and an organosiloxane (trade name “KF801” manufactured by Shin-Etsu Chemical Co., Ltd.)
0 ") 9.00 g (10 mmol) was added to N-methyl-2
-Dissolved in 450 g of pyrrolidone and reacted at room temperature for 12 hours. Thereafter, 32 g of pyridine and 71 g of acetic anhydride were added to this reaction solution, and a dehydration ring closure reaction was performed at 100 ° C. for 3 hours. Next, the reaction solution was purified by distillation under reduced pressure to obtain a polyimide solution having a solid content of 10%. A reaction vessel containing 100 parts of diethylene glycol monoethyl ether was kept at 85 ° C. under a nitrogen gas atmosphere, and 65 parts of n-butyl acrylate, 30 parts of dimethylaminoethyl acrylate, 5 parts of glycidyl methacrylate and 5 parts of azo Solution polymerization was carried out with stirring while continuously adding a mixed solution consisting of 1 part of bisisobutyronitrile over 5 hours. After completion of the dropwise addition, stirring was further continued at 85 ° C. for 2 hours to complete the solution polymerization, and an acrylic polymer solution having a solid content of 50% was obtained. After mixing 50 parts (solid content) of a polyimide solution, 30 parts (solid content) of an acrylic polymer solution, and 20 parts of “Epicoat YL980” (trade name, manufactured by Yuka Shell Epoxy), and reacting at 70 ° C. for 3 hours, ,
Acetic acid (3 parts) was gradually added and mixed to adjust the pH.
Next, 1000 parts of distilled water was gradually added and the mixture was stirred vigorously to obtain a cationic polyimide resin emulsion.

(Synthesis Example 2: Polyamic acid resin emulsion) 2,2.4 g of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride
(100 mmol) and 2,2-bis [4- (4-aminophenoxy)] sulfone 43.3 as a diamine compound
g (100 mmol) was dissolved in 450 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. The mixture was concentrated under reduced pressure to obtain a polyamic acid solution having a solid content of 15%. To 70 parts (solid content) of the polyamic acid solution, 30 parts of “Epicoat YX4000H” (trade name, manufactured by Yuka Shell Epoxy Co.) was added, mixed well, and allowed to react at 80 ° C. for 60 minutes. The mixture was stirred vigorously while gradually adding to 1000 parts of distilled water to which 10 parts of triethanolamine had been added, to obtain an anionic polyamic acid resin emulsion (an example of a polyimide resin emulsion).

(2) Preparation of Non-Film-Forming Fine Particle Dispersion (Synthesis Example 3: Aqueous Dispersion of Hollow Polymer Fine Particles) Step 1: 600 parts of ion-exchanged water, 27% solution of dodecyltrimethylammonium chloride (manufactured by Kao Corporation) 5 parts of brand name “Coatamine 24P”, 2,2′-azobis (2
-Methylpropionamidine) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., trade name "V-50"), 1 part, styrene 75
, 10 parts of acrylonitrile, 10 parts of 2-ethylhexyl acrylate, 5 parts of a quaternary methylene chloride salt of dimethylaminopropylacrylamide, and 15 parts of t-dodecylmercaptan were charged all at once and reacted at 70 ° C for 3 hours. After cooling, the reaction solution was filtered through a nylon 300 mesh to obtain seed particles A as swellable polymer particles. Step 2: 430 parts of ion-exchanged water, 10 parts of the seed particles A obtained in Step 1 (solid content), 2,2′-azobis (2-
1 part of methylpropionamidine) dihydrochloride (trade name “V-50” manufactured by Wako Pure Chemical Industries, Ltd.), 59 parts of methyl methacrylate, 12 parts of styrene, 28 divinylbenzene
The reaction mixture was charged at 70 ° C. for 3 hours, cooled, filtered through a nylon 300 mesh to remove coarse particles, and an aqueous dispersion containing styrene-based hollow polymer particles was obtained. The hollow polymer particles had an average particle diameter of 0.3 μm, a volume hollow ratio of 30%, a specific gravity of 0.7, and a relative dielectric constant of 1.9.

(Synthesis Example 4: Aqueous dispersion of styrene resin fine particles) The monomer composition used in Step 2 of Synthesis Example 3 was changed to 20 parts of styrene and 80 parts of divinylbenzene. Otherwise in the same manner as in Synthesis Example 3, an aqueous dispersion containing styrene-based resin fine particles was obtained. The styrene resin fine particles had an average particle diameter of 0.3 μm and a relative dielectric constant of 1.8.

(3) Preparation of Aqueous Dispersion for Forming Low Dielectric Insulating Film (Example 1) Non-film-forming fine particle dispersion was added to 80 parts (solid content) of the polyimide resin emulsion obtained in Synthesis Example 1. Of PTFE dispersion (manufactured by Daikin, trade name: “Polyflon”) as a sample was added and mixed well to obtain an aqueous dispersion. This aqueous dispersion was filled in a 2 L glass container, and a titanium-platinum electrode was used as the anode and a copper plate was used as the cathode, and an electrodeposition film was obtained on the copper plate by a constant voltage method. After that, 80 ° C x 1
Preliminary drying for 0 minutes and heat treatment at 250 ° C. for 30 minutes were performed to obtain a cured film (insulating film) having a thickness of 20 μm. The average particle diameter of the PTFE particles contained in the PTFE dispersion is 0.3 μm, and the relative dielectric constant is 2.0.

Example 2 The polyamic acid resin emulsion obtained in Synthesis Example 2 was used in place of the polyimide resin emulsion, and the heat treatment was performed at 250 ° C. for 30 minutes.
A cured film having a thickness of 20 μm was obtained in the same manner as in Example 1 except that the temperature was changed to 50 ° C. × 60 minutes.

Example 3 The same procedure as in Example 1 was repeated except that 50 parts (solid content) of a polyimide resin emulsion and 50 parts (solid content) of a PTFE dispersion were used.
m was obtained.

Example 4 The same procedure as in Example 1 was carried out except that the styrene resin fine particle dispersion obtained in Synthesis Example 4 was used in place of the PTFE dispersion as the non-film-forming fine particle dispersion. A cured film having a thickness of 20 μm was obtained.

Example 5 The thickness of the non-film-forming fine particle dispersion was the same as in Example 1 except that the hollow polymer fine particle dispersion obtained in Synthesis Example 3 was used instead of the PTFE dispersion. A cured film of 20 μm was obtained.

Comparative Example 1 A cured film having a thickness of 20 μm was obtained in the same manner as in Example 1 except that the non-film-forming fine particles were not used.

(4) Performance Evaluation The cured films obtained in Examples 1 to 5 and Comparative Example 1 were evaluated as follows. The results are shown in Tables 1 and 2. [Pencil hardness] Measured according to JIS K 5400. [Relative permittivity, dielectric loss tangent, volume resistivity and surface resistivity]
It was measured in accordance with JIS C6481. [Adhesive strength] A measuring pin was fixed to the film surface with an epoxy adhesive, and the adhesive strength was measured. [HAST test (moisture and heat resistance)]
A HAST test (moist heat resistance test) was performed for 72 hours under conditions of 121 ° C., 100% humidity, and 2 atm, and infrared spectroscopy was performed before and after the test. evaluated. ○ ・ ・ ・ No change and resistance is observed × ・ ・ ・ Change is large and resistance is not observed

[0065]

[Table 1]

[0066]

[Table 2]

As can be seen from a comparison between Example 1 and Comparative Example 1 which does not contain non-film-forming fine particles having a low dielectric constant, the aqueous dispersion of the present invention containing the non-film-forming fine particles having a low dielectric constant can be used as an electrode. According to the cured film formed by the deposition, the relative dielectric constant could be significantly reduced from 3.2 to 2.7 without lowering other physical properties. Also, the cured coatings of Examples 2 to 5,
In each case, the relative dielectric constant at 1 MHz was as low as 3 or less, the hardness, the surface and the resistivity were high, and the adhesiveness to the substrate and the wet heat resistance were excellent.

[0068]

According to the aqueous dispersion for forming a low dielectric constant insulating film of the present invention, this dispersion is used for electrodeposition by electrodeposition.
An insulating film having a low dielectric constant and good adhesion can be formed. Since the low dielectric constant insulating film of the present invention is produced by electrodeposition using the above-mentioned aqueous dispersion, it is excellent in the controllability of the film thickness and the controllability of the film formation position as compared with the case where it is produced by coating. That is, since a thin and uniform low-dielectric-constant insulating film can be easily formed at an arbitrary position, it is suitably used in electronic parts such as a printed circuit board, a semiconductor package, a chip coil, and a high-frequency antenna. Since the electronic component of the present invention includes the low dielectric constant film, the electronic component can be reduced in size and thickness.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H01L 21/312 H01L 21/312 BA 21/768 21/90 PS F Term (Reference) 4F070 AA55 AB01 AC79 AD03 AE30 CA01 CB03 CB12 4J038 CC012 CC022 CC082 CD091 CD122 CG141 CG142 CH032 CH122 CH201 CH261 CJ052 DB001 DJ021 DJ031 DL031 DL032 KA03 KA21 MA08 MA10 NA17 NA21 PA19 PB09 PB11 PC02 PC03 PC08 5F033 RR21 AC24 RR22 AC24 RR22 AC24 RR22 RR22 AC24 RR22 RR23 AG01

Claims (5)

[Claims] 1. A non-film-forming fine particle having an average particle diameter of 1 μm or less and a relative dielectric constant of 3 or less, and organic particles comprising at least one of a polymerizable compound and a polymer are dispersed in an aqueous medium. An aqueous dispersion for forming a low dielectric constant insulating film, wherein the insulating film can be formed by deposition. 2. The aqueous dispersion for forming a low dielectric constant insulating film according to claim 1, wherein the non-film-forming fine particles are at least one selected from fluorine-containing fine particles and crosslinked organic fine particles. 3. The organic particles have a charge on the particle surface,
3. The aqueous dispersion for forming a low dielectric constant insulating film according to claim 1, comprising a polyimide resin. 4. A low dielectric constant film formed by electrodeposition using the aqueous dispersion liquid for forming a low dielectric constant insulating film according to claim 1 and having a relative dielectric constant of 3 or less. Dielectric insulating film. 5. An electronic component comprising a low dielectric constant insulating film formed by electrodeposition using the aqueous dispersion for forming a low dielectric constant insulating film according to any one of claims 1 to 3. .