JP2000315845A - Circuit board - Google Patents

Abstract

(57) [Problem] To provide a circuit board which has excellent productivity and insulating properties, has a substrate made of an insulating material having a low dielectric constant and a low dielectric loss tangent, and can be used in a high frequency region. SOLUTION: The weight loss temperature by TGA is 14% by weight.
A circuit board having at least one insulating layer made of an insulating material having a temperature in a range of 0 to 300 ° C. and a dielectric constant of 3.5 or less is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board which has excellent productivity and insulating properties, has a substrate made of an organic insulating material having a low dielectric constant and a low dielectric loss tangent, and can be used in a high frequency range.

[0002]

2. Description of the Related Art A predetermined number of prepregs obtained by impregnating and drying a thermosetting resin such as an epoxy resin or a polyimide on a woven glass fiber base material are laminated and heated for use as a substrate of an electronic circuit board. Pressure molded laminates have been manufactured. The dielectric constant of these laminates is between 4.9 and
Since it is high at 5.1, the capacitance of a circuit board using this as a substrate becomes large, and as a result, it is not suitable as a circuit board for handling high frequencies such as occurrence of crosstalk between circuits formed on the board. Was. As a method for obtaining a circuit board laminate having a low dielectric constant, it has been proposed to fill hollow glass particles in a thermosetting resin (JP-A-56-492).
No. 56, JP-A-56-49257, JP-A-5-49257
1387974 and JP-A-8-46309). Gases such as air and nitrogen are present inside the hollow glass particles, and since the gas has a low dielectric constant, the dielectric constant of the entire laminate is reduced.

However, the method of filling hollow glass particles into a thermosetting resin, which is conventionally known, has a poor affinity for the hollow glass particles and makes it difficult to uniformly disperse the same in the resin. In the laminated board, voids are easily generated inside. It is not practical to use a laminate having voids formed therein as a substrate of a circuit board, because the mechanical strength of the substrate is significantly deteriorated.

Further, with the increase in the density of circuit boards, a multilayer circuit board in which boards on which circuits are formed has been recently developed, but also in this case, the dielectric constant of the board can be further reduced without impairing the insulating property. Has been requested. Also, in the case of a multilayer circuit board, an insulating layer is provided between the boards to avoid contact of circuits formed on the surface of each board and to insulate between circuits,
When a semiconductor element is mounted on a single-layer or multi-layer circuit board, a sealing material layer is provided in a gap between the circuit board and the semiconductor element. Similar insulating properties and low dielectric constant are required.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit board having a substrate made of an organic insulating material having excellent productivity and insulating properties, and having a low dielectric constant and a low dielectric loss tangent. It is another object of the present invention to provide a highly reliable circuit board that can be used in a high frequency range.

[0006]

According to the present invention, the following circuit board is provided to achieve the above object of the present invention. (1) A 10% weight loss temperature by TGA is 140 to 30
A circuit board comprising at least one board made of an organic insulating material having a temperature of 0 ° C. and a dielectric constant of 3.5 or less. (2) The circuit board according to the above (1), wherein the organic insulating material contains an organic polymer forming a continuous phase. (3) The circuit board according to (2), wherein the organic polymer is a thermosetting resin. (4) The circuit board as described in (2) or (3) above, wherein the organic insulating material contains crosslinked resin particles dispersed in an organic polymer forming a continuous phase. (5) The circuit board according to (4), wherein the crosslinked resin particles are hollow particles having a hollow structure. (6) The circuit board according to any one of the above (1) to (5), wherein the organic insulating material is composited with the base material. (7) The above (1) to (6), wherein a conductive portion having a circuit formed on one or both surfaces of the substrate is provided.
The circuit board according to any one of the above. (8) The circuit board according to any one of (1) to (7), wherein a plurality of substrates are present, and an insulating layer made of an organic insulating material is provided between the substrates.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The circuit board of the present invention has a 10% weight loss temperature by TGA of 14%.
0 to 300 ° C., preferably 150 to 290 ° C., more preferably 190 to 280 ° C., and at least one substrate made of an organic insulating material having a dielectric constant of 3.5 or less, preferably 3.4 or less. Have. The organic insulating material constituting the substrate of the circuit board of the present invention preferably contains an organic polymer, which forms a continuous phase in the organic insulating material. Further, it is more preferable that the crosslinked resin particles are dispersed in the organic polymer forming the continuous phase. Such an organic insulating material can be obtained by molding and processing a composition for an organic insulating material containing crosslinked resin particles. The “crosslinked resin” in the above crosslinked resin particles means a resin having a crosslinked structure and having a glass transition temperature (Tg) measured by DSC of preferably 10 ° C. or more, more preferably 50 ° C. or more.

The crosslinked resin particles contained in the composition for an organic insulating material have the following characteristics: (i) a dielectric constant of 4 or less, preferably 3 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. . When the dielectric constant of the crosslinked resin particles satisfies the above range, the organic insulating material formed from the composition for an organic insulating material has a low dielectric constant. Further, the crosslinked resin particles preferably have the following characteristics. (Ii) The average particle size is 0.03 to 10 μm, preferably 0.1 to 2 μm, more preferably 0.2 to 1 μm. (Iii) The average metal ion concentration contained in the particles is 50 pp
m, preferably 40 ppm or less, more preferably 2 ppm or less.
0 ppm or less. (Iv) A 10% weight loss temperature by TGA (thermogravimetric analysis) is preferably 200 ° C. or higher, more preferably 220 to 200 ° C.
400 ° C, particularly preferably 250 to 380 ° C. (V) a dielectric loss tangent (tan δ) of preferably 0.1 or less;
More preferably 0.05 or less, especially 0.01 or less. Having the property (ii) facilitates fine dispersion of the crosslinked resin particles in the composition. Having the characteristic (iii) facilitates satisfying the characteristics (i) and (v). Having the property of (iV) indicates that the crosslinked resin particles have excellent heat resistance, and the crosslinked resin particles are substantially heated even when heat is applied during the forming process of the composition for an organic insulating material of the present invention and when using solder. Can be prevented from causing a significant change. By having the characteristic (v), the organic insulating material has a low dielectric loss tangent, and it is possible to reduce heat generation when a circuit board using the same is used in a high frequency region.

The metal ion in the above (iii) is a metal ion that affects the insulating property, dielectric constant, dielectric loss tangent, etc. of the organic insulating material. For example, Na, K, Li, Fe, Ca,
Cu, Al, Mn, Sn and the like can be mentioned. In order to make the metal ion concentration in the crosslinked resin particles as described in the above (iii), there are the following methods, and these methods can be used alone or in combination of two or more. An emulsifier used for polymerization for producing crosslinked resin particles,
An initiator containing no metal ion is used. As a water used as a polymerization solvent for the polymerization, water having a small amount of metal ions such as ion-exchanged water is used. After the polymerization, purification is performed using ultrafiltration or a centrifuge. After the polymerization, acid and salt are coagulated and washed with washing water having a small amount of metal ions such as ion exchange water. The chlorine ion concentration in the crosslinked resin particles is preferably 50 ppm or less, more preferably 40 ppm or less, particularly preferably 20 ppm or less from the viewpoint of corrosion resistance. In producing the crosslinked resin particles, an ammonium salt type anionic emulsifier, a nonionic emulsifier, and an organic acid salt type cationic emulsifier are suitably used as the emulsifier used for the polymerization. As the initiator, an organic peroxide, an azo compound or an ammonium salt type persulfate is suitably used.

The crosslinked resin particles used in the present invention are preferably hollow particles having a hollow structure (hereinafter also referred to as “hollow crosslinked resin particles”). The hollow crosslinked resin particles contain a gas having a small dielectric constant, such as air or nitrogen, and can easily have a low dielectric constant. In addition, since it has good affinity with polymers and the like, the organic insulating material obtained by molding and processing an organic insulating material composition containing hollow cross-linked resin particles described below does not generate voids and the mechanical properties of the organic insulating material are reduced. There is no loss of target strength. The hollow crosslinked resin particles preferably satisfy the properties (i) to (v) of the crosslinked resin particles, and further satisfy the following properties from the viewpoint of further lowering the dielectric constant. (Vi) The inner diameter is 0.1 to 0.9 times, more preferably 0.2 to 0.9 times, particularly preferably 0.3 to 0.9 times the outer diameter. (Vii) The average specific gravity of the hollow crosslinked resin particles is 0.5 to 1.
2, more preferably 0.6 to 1.1, particularly preferably 0.65 to 1.0.

In the present invention, the dielectric constant and the dielectric loss tangent (tan δ) are set at a frequency of 1 according to JIS C6481.
0 is a value measured at ⁶ Hz.

The polymer of the crosslinked resin particles satisfies the above condition (i), and preferably further satisfies the above conditions (ii) to (iv).
There is no particular limitation as long as it satisfies (iv), and it can be appropriately selected from polymers produced by addition polymerization, polycondensation and the like. Among them, crosslinking monomers 1
100% by weight, preferably 2 to 80% by weight, more preferably 5 to 60% by weight, and non-crosslinkable monomer 0 to 99% by weight, preferably 20 to 98% by weight, more preferably 40% by weight.
To 95 are preferable. Here, the total amount of the crosslinkable monomer and the non-crosslinkable monomer is 100% by weight.

The method of producing the hollow crosslinked resin particles preferably used is not particularly limited, and examples thereof include the following methods (I) to (VIII) (see Japanese Patent Publication No. 4-68324). (I) A method in which a foaming agent is contained in polymer particles, and after the foaming agent is foamed, a crosslinking monomer is absorbed and polymerized. (II) A method in which a volatile substance such as butane is sealed in a polymer, the volatile substance is gasified and hollowed out, and then a crosslinking monomer is absorbed and polymerized. (III) A method in which a polymer is melted, a gas jet such as air is blown into the polymer, air bubbles are enclosed, and then a crosslinking monomer is absorbed and polymerized. (IV) A method in which an alkali-swellable substance is permeated into polymer particles to swell the alkali-swellable substance, and then absorbs and polymerizes a crosslinking monomer. (V) A method in which an oil-in-water type crosslinkable monomer emulsion is prepared and polymerized. (VI) A two-stage polymerization method in which a polymer particle is used as a seed to absorb and then polymerize and crosslink a monomer having a specific composition including a crosslinkable monomer. (VII) A method of producing by crosslinking polymerization of a crosslinkable monomer. (VIII) A method of spray-drying the crosslinkable polymer particles.

Among the above methods, the two-stage polymerization method (VI) is preferred. The two-stage polymerization method (VI) is preferably performed in the following manner. That is, (a) 1 to 50% by weight of a crosslinkable monomer (hereinafter also referred to as “polymerizable monomer (a)”),
A hydrophilic monomer comprising 1 to 40% by weight of a non-crosslinkable unsaturated carboxylic acid and / or 5 to 99% by weight of another hydrophilic monomer (hereinafter, also referred to as "polymerizable monomer (b)") ) 1
To 99% by weight, and (c) other non-crosslinkable copolymerizable monomer (hereinafter referred to as "polymerizable monomer (c)").
Polymerizable monomer component 1 comprising 0 to 85% by weight
00 parts by weight of these polymerizable monomer components [(a),
(B), a polymer seed different from the polymer obtained by polymerizing (c)] (hereinafter also referred to as “heterogeneous polymer”)
It is preferable to disperse in water in the presence of 1 to 100 parts by weight, and then polymerize the polymerizable monomer component (see JP-A-62-227336).

[0015] The hollow crosslinked resin particles obtained in the above embodiment are used as a seed polymer, and the above polymerizable monomer (a),
By subjecting at least one selected from (b) and (c) to seed polymerization, hollow crosslinked resin particles having at least two polymer layers used in the present invention can also be produced (Japanese Unexamined Patent Publication No. 140271 and 2
-140272).

The polymerizable monomer (a) is not particularly restricted but includes, for example, divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate and allyl methacrylate. Monomer,
Alternatively, a trivinyl monomer can be used. Among them, divinylbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate are preferred. The polymerizable monomer (b) is not particularly limited. For example, vinyl pyridine, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, N-methylol acrylamide, N-methylol methacrylamide, acrylic Examples include vinyl monomers such as acid, methacrylic acid, itaconic acid, fumaric acid, sodium styrenesulfonate, vinyl acetate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. it can. Of these, methacrylic acid, itaconic acid and acrylic acid are preferred. The 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; ethylenically unsaturated carboxylic acid alkyl esters such as ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, and lauryl methacrylate; phenylmaleimide, cyclohexylmaleimide Maleimide compounds; conjugated diolefins such as butadiene and isoprene. Of these, styrene is preferred.

The different polymer is different from a polymer obtained by polymerizing at least the polymerizable monomers (a) to (c). Here, "different" means
This is a broad concept that includes different types of polymerization monomers, different molecular weights even when the copolymerization monomers are the same, and different copolymerization ratios even when the same copolymerization monomers are used. .

The heterogeneous polymer is not particularly limited. For example, polystyrene, carboxy-modified polystyrene, carboxy-modified styrene-butadiene copolymer, styrene-butadiene copolymer, styrene-acrylester copolymer, styrene-methacrylester copolymer, styrene- Acrylic ester copolymers, methacrylic ester copolymers, carboxy-modified (styrene-acrylic ester) copolymers, carboxy-modified (styrene-methacrylic ester) copolymers and the like can be mentioned. Among them, a preferred heteropolymer is a polystyrene and a styrene copolymer containing 50% by weight or more of a styrene component.

The degree of crosslinking of the hollow crosslinked resin particles is determined by heating,
When pressurizing to form the insulating plate, it is preferable that the hollow crosslinked resin particles are crosslinked so as to maintain the shape of the particles.

According to such a method, particularly according to the method (VI) described in detail above, the average particle diameter is -20% to + 20%.
Particles having a particle size of 70% by weight or more and having a uniform particle size are obtained. The use of these particles achieves the object of the present invention more excellently and is preferred.

The composition for an organic insulating material may be combined with the above-mentioned crosslinked resin particles together with the above-mentioned crosslinked resin particles by any method, for example, heat curing, curing with a crosslinking agent, radiation or light (hereinafter, also referred to simply as “light”). Contains an organic compound that can be formed into a desired shape by a method such as melt extrusion. Examples of such an organic compound include a thermosetting resin, a thermoplastic resin, an unvulcanized rubber, and a photocurable compound. Hereinafter, such an organic compound is referred to as “resin” for convenience.

As the thermosetting resin, an imide resin,
Examples include, but are not limited to, phenolic resins, cyanate resins, cyanate ester resins, epoxy resins, unsaturated polyester resins, polycarbodiimide resins, bismaleimide triazine resins (BT resins).

Examples of the thermoplastic resin include polyolefin resins such as polyethylene resin, polypropylene resin, poly-1-butene resin and poly-4-methyl-1-pentene resin; polyester resins such as polyethylene terephthalate resin and polyethylene naphthalate resin; nylon 6, polyamide resin such as nylon 66; fluororesin such as polytetrafluoroethylene resin and polytrifuckerethylene resin; other polystyrene resin, polyvinyl chloride resin, polymethyl resin
Examples include (meth) acrylate resins, polycarbonate resins, polyethersulfone resins, and the like, but are not limited thereto.

Examples of the unvulcanized rubber include polybutadiene rubber, natural rubber, polyisoprene rubber, butyl rubber, chloroprene rubber, butadiene / styrene rubber, butadiene / acrylonitrile rubber, acrylic rubber, fluorine rubber, silicone rubber, and mixtures thereof. Although a composite etc. can be mentioned, it is not limited to these.

Examples of the photocurable compound include (meth) acrylate monomers, aromatic vinyl monomers and the like. Preferred specific examples thereof include ethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Trimethylolpropane tri (meth) acrylate, divinylbenzene and the like.

Among them, a preferred resin is a thermosetting resin, and the use of an epoxy resin is particularly preferred. Specific examples of the epoxy resin include known biphenyl-type epoxy resins, cresol novolak-type epoxy resins,
Phenol novolak epoxy resins, bisphenol A epoxy resins, and combinations thereof.

The unvulcanized rubber may be added to a thermosetting resin or a thermoplastic resin. By adding the unvulcanized rubber, flexibility can be imparted to the organic insulating material formed from the composition for an organic insulating material using a thermosetting resin or a thermoplastic resin.

In the composition for an organic insulating material of the present invention, the amount of the crosslinked resin particles mixed with the resin is such that the organic insulating material obtained from the composition for an organic insulating material of the present invention has a sufficient low dielectric constant and insulating properties. Considering that a jig is less worn when machining a circuit board having a substrate made of an organic insulating material with a drill or the like, preferably 1 to 200 parts by weight with respect to 100 parts by weight of the resin. , More preferably 5
-150 parts by weight, more preferably 10-100 parts by weight.

The composition for an organic insulating material of the present invention can contain other components as required in addition to the resin and the crosslinked resin particles. When the resin is a thermosetting resin, a known curing agent and a curing aid according to the type of the thermosetting resin are blended. Those skilled in the art can easily select the types of these curing agents and curing assistants. When the resin is an unvulcanized rubber, a vulcanizing agent known per se according to the type of the unvulcanized rubber,
A vulcanization aid, a crosslinking agent, and a crosslinking aid are blended. Those skilled in the art can easily select the type of the vulcanizing agent, vulcanizing aid or crosslinking agent, and crosslinking aid. When the resin is a photocurable compound, a photopolymerization initiator, a photosensitizer and the like are blended. In addition, the composition for an organic insulating material of the present invention includes an antioxidant, a flame retardant, a flame retardant auxiliary, a release agent, a coupling agent, a pigment, a dye, etc. as long as the object of the present invention is not impaired. Can be blended.

The preparation of the composition for an organic insulating material is appropriately performed depending on the type of the resin used. When the resin is a thermosetting resin, it is preferably prepared as a varnish using an inert solvent that dissolves the thermosetting resin. Which solvent is appropriate depends on the type of thermosetting resin,
The same solvent as used in preparing a conventionally known thermosetting resin varnish can be used. The crosslinked resin particles may be an aqueous dispersion or a dry powder, but it is preferable to blend the hollow crosslinked resin particles of the dry powder into a thermosetting resin varnish. You may. To form a sheet, the solvent of the varnish is evaporated or
Each component is melt-kneaded at a temperature at which a curing reaction does not substantially occur using a roll, and then roll-rolled into a sheet.

When the resin is a thermoplastic resin or an unvulcanized rubber, the unvulcanized rubber and the crosslinked resin particles, as well as necessary components and additives to be added as required, are mixed by a method known per se. , Melted and kneaded. As a device used for melting and kneading, a kneading device known per se such as a kneader, a single-screw extruder, a twin-screw extruder, and a Banbury mixer can be used.

When the resin is a photocurable compound, it is prepared as a varnish in which each component is dissolved, with or without using an inert solvent.

The composition for an organic insulating material of the present invention can be prepared as containing a base material. As a substrate,
Glass fibers and their woven fabrics, polyamide fibers and their woven fabrics or their nonwoven fabrics, polyester fibers and their woven fabrics or their nonwoven fabrics, Teflon fibers and their nonwoven fabrics, etc., as well as mixed nonwoven fabrics and mixed woven fabrics of these fibers, etc. . The woven fabric and the nonwoven fabric are in a sheet shape. An appropriate base material is selected depending on the use of the organic insulating material, but when used for a circuit board such as a printed wiring board, a glass fiber woven fabric is preferably used. When the resin is a thermosetting resin, after impregnating the base material, preferably woven fabric with varnish, it is possible to prepare a composition for an organic insulating material including the base material as a prepreg dried and B-staged. it can. Further, when the resin is a thermoplastic resin or unvulcanized rubber, when melt-kneading the crosslinked resin particles and other components, the base material, preferably by adding a non-sheet-like fiber, containing the base material A composition for an organic insulating material can be prepared.

The thus prepared composition for an organic insulating material of the present invention is molded and processed according to the intended use to obtain an organic insulating material. When the resin contained in the composition is a thermosetting resin, the organic insulating material can be obtained by heating according to the type and curing the resin into a desired shape. When the resin is a thermoplastic resin, an insulating material having a desired shape can be obtained by a method such as extrusion molding or injection molding. Further, for example, after forming into a sheet or film shape by extrusion molding, it can be subjected to thermoforming such as vacuum forming, pressure forming or the like to obtain a desired shape, and when the thermoplastic resin is radiation-crosslinkable, the sheet or Radiation may be applied for the purpose of increasing the strength of the film. When the resin is an unvulcanized rubber, when vulcanizing with a vulcanizing agent or a crosslinking agent, an organic insulating material can be obtained by heating. When the resin is a photocurable compound, an organic insulating material is formed by light irradiation.

The organic insulating material constituting the substrate according to the present invention contains the organic polymer forming the continuous phase as described above. The organic polymer forming the continuous phase is derived from the resin contained in the composition for an organic insulating material described above. Preferably, the crosslinked resin particles are finely dispersed in the organic polymer forming the continuous phase.

The dielectric constant of the organic insulating material is 3.5 or less,
Preferably it is 3.4 or less. The dielectric loss tangent is 0.0
5 or less, more preferably 0.01 or less.
Or less, particularly preferably 0.005 or less. The temperature at which the organic insulating material is reduced by 10% by weight by TGA is 140%.
-300 ° C, preferably 150-290 ° C, particularly preferably 190-280 ° C. It is preferable to be within this temperature range, particularly when the resin is a thermosetting resin, because the productivity of the organic insulating material is further excellent.

Thus, the organic insulating material according to the present invention has excellent insulating properties, a low dielectric constant and a low dielectric loss tangent.
It is suitable as a board that constitutes a circuit board for mounting a semiconductor element such as I. The circuit board of the present invention has one or more substrates made of the above-mentioned organic insulating material. Usually, a conductive portion made of a metal foil on which a circuit is formed, preferably a copper foil or a gold-plated copper foil is provided on one or both surfaces of the substrate.

When a plurality of substrates are present on the circuit substrate of the present invention, it is preferable that an insulating layer between the substrates provided on the substrate for insulation between circuits is made of the above-mentioned organic insulating material.
Further, it is preferable that a sealing material layer provided in a gap between the semiconductor element and the circuit board when the semiconductor element is mounted on the circuit board of the present invention (for example, flip mounting) is made of the organic insulating material. The circuit board of the present invention is a board constituting the circuit board,
It is preferable that all of the insulating layer between the substrates and the sealing material layer provided in the gap between the semiconductor element and the circuit board when the semiconductor element is mounted are made of the organic insulating material.

As described above, in the circuit board of the present invention, the substrate constituting the circuit board is made of the organic insulating material, and preferably, at least one of the insulating layer and the sealing material layer is made of the organic insulating material. The dielectric loss tangent of the circuit board of the present invention is preferably 0.05 or less, more preferably 0.01 or less, and particularly preferably 0.005 or less.

In the circuit board of the present invention, when the organic insulating material is used as an insulating layer between the substrates when there are a plurality of substrates constituting the circuit board, the thickness thereof is the same as that of the conventional circuit board. It is usually from 20 to 100 μm, preferably from 40 to 90 μm, more preferably from 50 to 70 μm. When the insulating material is used as a sealing material layer provided in a gap between the semiconductor element and the circuit board when the semiconductor element is mounted on the circuit board, the thickness is the same as that of the conventional circuit board. It is preferable to match with. As a resin used for the insulating layer or the sealing material layer between these substrates, a thermosetting resin, particularly an epoxy resin, is preferable. As a method for forming the insulating layer and the sealing material layer, a conventionally used method can be adopted. For example, a method described in JP-A-10-289969 can be adopted.

The structure of the circuit board of the present invention is as follows. Is substantially the same as a conventionally known circuit board. For example, when the circuit board of the present invention is a multilayer rigid printed wiring board, the board is preferably made of a thermosetting resin, particularly an epoxy resin, and furthermore, a base material, especially a glass woven fabric is used for reinforcement. It is preferable to use an organic insulating material. Such a multilayer rigid printed wiring board often has four or more layers, and sometimes has ten or more layers, and is used in the field of communications such as a computer field and a mobile phone. The thickness of each substrate of the multilayer rigid printed wiring board is usually 20 to 100
μm, preferably 40 to 90 μm, more preferably 50 μm
７０70 μm. The total thickness of the entire multilayer printed wiring board is usually 1 to 10 mm, preferably 1.5 to 8 mm, more preferably 2 to 6 mm. Further, those using paper as the base material and phenol resin as the resin can be used as a single-layered single-sided or double-sided rigid printed wiring board. Further, when the circuit board of the present invention is a flexible printed wiring board, an imide resin or a polyester resin is preferably used as the resin of the substrate (film). The thickness of the film is usually 25 to 50 μm.

The above-mentioned rigid printed wiring board and flexible printed wiring board can be manufactured by a known method.

[0043]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The percentages and parts in the examples are on a weight basis unless otherwise specified. Various measurements in the examples and comparative examples were performed by the following methods. (1) Metal ion concentration: The amount of metal ions of sodium and potassium was measured by an atomic absorption method. The amounts of metal ions other than sodium and potassium were below the detection limit. (2) Average particle size: The particle size of 100 particles was measured with an electron microscope, and the average value was determined. (3) Thermal weight loss temperature: A 10% weight loss temperature was measured by TGA under a nitrogen atmosphere at 10 ° C./min. (4) Dielectric constant and dielectric loss tangent: Measured at a frequency of 10 ⁶ Hz in accordance with JIS C6481. (5) Solder heat resistance: Floating on a 260 ° C. solder bath and the time until blistering was measured. (6) Insulation resistance: Pressure cooker (121 ° C) 6
After the time treatment, the measurement was performed according to JIS C6481.

Production Example 1 Distilled water (200 parts) was added to 70 parts of styrene, 27 parts of butadiene, 3 parts of itaconic acid and 12 parts of t-dodecyl mercaptan.
The resulting mixture was polymerized at 75 ° C. for 8 hours while stirring an aqueous solution in which 0.5 part of a reactive emulsifier SE10N (manufactured by Adeka) and 1.0 part of ammonium persulfate were dissolved to obtain polymer particles. The polymer particles have an average particle size of 0.24 μm, a toluene-insoluble content of 6%, a number average molecular weight by GPC of 5,000, and a ratio of weight average molecular weight to number average molecular weight (Mw
/ Mn) was 2.6. Next, the following polymerization was carried out using the polymer particles as a seed polymer. That is,
10 parts of the polymer particles, 0.1 part of polyoxyethylene nonyl phenyl ether, 0.4 part of ammonium lauryl sulfate and 0.5 part of ammonium persulfate were mixed with 9 parts of distilled water.
Dispersed in 00 parts. Methyl methacrylate 50
Parts, divinylbenzene 40 parts, α-methylstyrene 10
And a mixture of 20 parts of toluene at 75 ° C. for 5 hours.
After polymerization for a period of time, a dispersion of capsule particles containing toluene inside the particles was obtained with a polymerization yield of 98%. After this dispersion was subjected to a steam strip treatment, the polymer particles were observed with a transmission electron microscope. The polymer particles were transparent at the center and were perfectly spherical hollow fine particles. The average outer diameter of the particles was 0.44 μm, the average inner diameter was 0.3 μm, and the specific gravity was 0.72. The average metal ion concentration of the obtained polymer fine particles was 5 pp.
m, the weight loss temperature at 10% by weight was 320 ° C. The obtained crosslinked resin fine particles were spray-dried to obtain crosslinked resin particle powder A. The obtained crosslinked resin particle powder A was coated with the resin varnish (3) prepared in Example 1 described later.
(03.2 parts by weight), embedded in 100 parts by weight, the dielectric constant was measured, and the dielectric constant of the crosslinked resin particle A was calculated by Maxwell Model. As a result, the dielectric constant was 1.9.

Production Example 2 Reactive emulsifier S was added to 97 parts of styrene, 3 parts of acrylic acid and 12 parts of t-dodecyl mercaptan, and 200 parts of distilled water.
While stirring an aqueous solution in which 1.0 part of E10N (manufactured by Adeka) and 1.0 part of ammonium persulfate were dissolved, polymerization was carried out at 75 ° C. for 8 hours to obtain polymer particles. The average particle size of the polymer particles is 0.18 μm, and the
%, The number average molecular weight by GPC was 6,000, and the ratio (Mw / Mn) between the weight average molecular weight and the number average molecular weight was 4.0. Next, the following polymerization was carried out using the polymer particles as a seed polymer. That is, the polymer particles 10
Parts, polyoxyethylene nonyl phenyl ether 0.3
Part, ammonium lauryl sulfate 0.2 part and α, α ′
1 part of azobisisobutyronitrile was dispersed in 900 parts of distilled water. 80 parts of styrene and 2 parts of divinylbenzene
0 parts, and the mixture was polymerized at 75 ° C. for 5 hours. As a result, a dispersion of crosslinked particles was obtained with a polymerization yield of 98%. After performing a steam strip process on this dispersion,
Observation of the polymer particles with a transmission electron microscope revealed complete spherical hollow fine particles. The average particle size of the particles was 0.40 μm. The obtained crosslinked resin particles had an average metal ion concentration of 3 ppm, a 10% by weight heat loss temperature of 350 ° C, and a glass transition temperature of 200 ° C or more. The obtained crosslinked resin particles were spray-dried to obtain crosslinked resin particle powder B. 100 parts by weight of the obtained crosslinked resin particle powder B was blended and embedded in the resin varnish (303.2 parts by weight) prepared in Example 1 described below, the dielectric constant was measured, and the crosslinked resin was measured using Maxwell Model. When the dielectric constant of the particle B was calculated, the dielectric constant was 2.1.

Production Example 3 Reactive emulsifier S was added to 96 parts of styrene, 4 parts of methacrylic acid and 5 parts of t-dodecyl mercaptan, and 200 parts of distilled water.
While stirring an aqueous solution in which 0.3 part of E10N (manufactured by Adeka) and 1.0 part of ammonium persulfate were dissolved, polymerization was carried out at 75 ° C. for 8 hours to obtain polymer particles. The average particle size of the polymer particles is 0.3 μm, the toluene-insoluble content is 6%,
The number average molecular weight by GPC was 8,000, and the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight was 3.2. Next, the following polymerization was carried out using the polymer particles as a seed polymer. That is, the polymer particles 10
Parts, polyoxyethylene nonyl phenyl ether 0.3
Part, ammonium lauryl sulfate 0.2 part and α, α ′
1 part of azobisisobutyronitrile was dispersed in 900 parts of distilled water. To this, a mixture of 90 parts of styrene and 10 parts of trimethylolpropane trimethacrylate was added, and
After polymerization at 5 ° C. for 5 hours, a dispersion of crosslinked resin particles was obtained with a polymerization yield of 98%. After this dispersion was subjected to a steam strip treatment, the crosslinked resin particles were observed with a transmission electron microscope to find that the particles were completely spherical hollow fine particles. The average particle size of the particles was 0.67 μm. Moreover, the average metal ion concentration of the obtained polymer fine particles was 2 ppm, and the 10% by weight heat loss temperature was 330 ° C. The obtained crosslinked resin particles were spray-dried to obtain crosslinked resin particle powder C. The obtained crosslinked resin particle powder C was blended with 100 parts by weight of the resin varnish (303.2 parts by weight) prepared in Example 1 described below and embedded, the dielectric constant was measured, and the crosslinked resin was measured with Maxwell Model. When the dielectric constant of the particle C was calculated, the dielectric constant was 2.1.

Production Example 4 In Production 1, 0.4 parts of sodium lauryl sulfate was used instead of ammonium lauryl sulfate as an emulsifier, 0.5 parts of sodium persulfate was used instead of ammonium persulfate, and 50 parts of methyl methacrylate and 40 parts of divinylbenzene were used.
And non-crosslinked resin particles were obtained in the same manner except that 100 parts of methyl methacrylate was used instead of 10 parts of α-methylstyrene. The average particle size of the non-crosslinked resin particles is 0.
50 μm, average metal ion concentration is 500 ppm, 10% by weight heat loss temperature is 180 ° C., glass transition temperature is 103 ° C.
Met. The obtained non-crosslinked resin particles were spray-dried to obtain non-crosslinked resin particle powder D. 100 parts by weight of the obtained non-crosslinked resin particle powder D was blended and embedded in the resin varnish (303.2 parts by weight) prepared in Example 1 described later, the dielectric constant was measured, and Maxwell Mo was measured.
When the dielectric constant of the non-crosslinked resin particles D was calculated by del, the dielectric constant was 4.3.

Table 1 shows the composition and physical properties of the polymer fine particles A to D produced as described above.

[0049]

[Table 1]

The abbreviations in Table 1 are as follows. ST: Styrene, BD: Butadiene, TA: Itaconic acid, AA: Acrylic acid, MA: Methacrylic acid, DVB: Divinylbenzene, TMPMA: Trimethylolpropane trimethacrylate MMA: Methyl methacrylic acid, AMS: α-methylstyrene

Examples 1 to 3 100 parts by weight of epoxy resin Ep-1001 (trade name, manufactured by Yuka Shell Epoxy Co., epoxy equivalent: 480)
3 parts by weight of dicyandiamide, 2-ethyl-4 as a catalyst
-Methyl imidazole 0.2 part by weight and ethyl carbitol 200 parts by weight as a solvent were added to prepare a resin varnish. 100 parts by weight of the dry powders A to C of the crosslinked resin particles obtained in Production Examples 1 to 3 were mixed with the resin varnish, and the varnish was impregnated and dried in a glass fiber woven fabric (basis weight: 215 g) to dry the resin. One layer of prepreg (a) of 50% by weight was obtained. Furthermore, copper foil (thickness 18μ)
m) at a temperature of 170 ° C. and a pressure of 40 kg / cm ² .
The molded body was heated and pressed for one minute to obtain a copper-clad insulating plate having a thickness of 0.2 mm. Table 2 shows the properties of the obtained copper-clad insulating plate (circuit board). Further, a measurement sample was cut out from the produced insulating plate so that the copper foil did not adhere, and the 10% by weight temperature was measured. Table 2 shows the measurement results.

Example 4 Eight prepregs (a) of Example 4 were stacked, and copper foil (thickness: 18 μm) was further stacked on both outer sides thereof. A 1.6 mm insulating plate was obtained.
Table 2 shows the characteristics. Further, a measurement sample was cut out from the produced insulating plate so that the copper foil did not adhere, and the 10% by weight temperature was measured. Table 2 shows the measurement results.

Comparative Examples 1 and 2 In the same manner as in Example 1, except that hollow spherical glass powder (average particle diameter: 10 μm) and non-crosslinked resin particle powder D were used instead of crosslinked resin particle powder A, respectively. Thus, a copper-clad insulating plate was obtained. Table 2 shows the characteristics of the obtained insulating plate.
Shown in Table 2 shows the 10% weight loss temperature measured in the same manner as in Example 1.

Comparative Example 3 A copper-clad insulating plate was obtained in the same manner as in Example 4, except that the non-crosslinked resin fine particle powder D was used instead of the polymer particle powder A. Table 2 shows the properties of the obtained insulating plate. In addition, 10 measured in the same manner as in Example 1.
Table 2 shows the weight percent weight loss temperature.

[0055]

[Table 2]

From the results shown in Table 2, the copper-clad insulating plates (circuit boards) of Examples 1 to 4 have excellent solder heat resistance, high insulation resistance, low dielectric constant and dielectric loss tangent, and excellent electrical characteristics. It is clear that this is suitable as a board constituting a circuit board. In addition, during the production of the insulating plate, the formability and workability were good. On the other hand, the copper-clad insulating plates of Comparative Examples 1 to 3 have a large dielectric constant, a low insulation resistance, a large dielectric loss tangent, and are inferior in electrical characteristics as a substrate.

[0057]

The circuit board of the present invention can be used for a high-frequency region because the board constituting the circuit board is made of an organic insulating material having excellent insulating properties and a low dielectric constant and a low dielectric loss tangent. Excellent reliability such as low crosstalk and low heat generation when used after mounting. Further, since the organic insulating material is excellent in moldability and workability, it is excellent in productivity.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F072 AA02 AA04 AA07 AA08 AB05 AB06 AB09 AB28 AB29 AD05 AD09 AD13 AD23 AD38 AD45 AG03 AH02 AH21 AJ01 AJ04 AK05 AK14 AL13 AL14 4J002 AA001 AA012 AC011 AC021 BC012 BG012 BG012 BG012 BG012 BG012 CD061 CF211 CM021 CM041 5E346 AA12 AA15 AA26 BB01 CC04 CC08 CC09 DD02 EE09 HH05 HH08

Claims (8)

[Claims] 1. The temperature at which a 10% weight loss by TGA is 14
A circuit board comprising at least one substrate made of an organic insulating material having a temperature in a range of 0 to 300 ° C. and a dielectric constant of 3.5 or less. 2. The circuit board according to claim 1, wherein the organic insulating material contains an organic polymer forming a continuous phase. 3. The circuit board according to claim 2, wherein the organic polymer is a thermosetting resin. 4. The circuit board according to claim 2, wherein the organic insulating material contains crosslinked resin particles dispersed in an organic polymer forming a continuous phase. 5. The circuit board according to claim 4, wherein the crosslinked resin particles are hollow particles having a hollow structure. 6. The circuit board according to claim 1, wherein the organic insulating material is composited with the base material. 7. The substrate according to claim 1, wherein a conductive portion having a circuit formed on one or both surfaces of the substrate is provided.
7. The circuit board according to any one of 6. 8. The circuit board according to claim 1, wherein there are a plurality of boards, and an insulating layer made of an organic insulating material is provided between the boards.