TWI819715B - Adhesive resin sheet, printed wiring board, and electronic equipment - Google Patents

Abstract

The purpose of this disclosure is to provide an adhesive resin sheet that exhibits excellent dielectric loss tangent in high frequency bands (10 GHz, 20 GHz, 40 GHz) and exhibits high migration resistance and excellent of bending. The above problems can be solved by providing an adhesive resin sheet that satisfies the following i to iv when heated at 180° C. for 1 hour. i: At 23°C, the dielectric loss tangent at a frequency of 10 GHz is measured to be 0.005 or less. ii: The dielectric loss tangent at a measured frequency of 20 GHz is 0.007 or less at 23°C. iii: The dielectric loss tangent at a measured frequency of 40 GHz is 0.01 or less at 23°C. iv: The temperature at which the mass reduction rate is 5% measured based on the thermogravimetric measurement stipulated in Japanese Industrial Standard K7120, using the inflow gas: nitrogen, the measurement temperature range: 25°C to 500°C, and the heating rate: 10°C/min. Above 280℃.

Description

Adhesive resin sheets, printed wiring boards and electronic equipment

This disclosure relates to an adhesive resin sheet. Furthermore, the present invention relates to a printed wiring board and electronic equipment including a cured product of the adhesive resin sheet.

In recent years, the field of electronics has developed at an extraordinary pace and requires high-speed processing of large amounts of information. The frequency band of signals used in printed wiring boards used in electronic equipment, communication equipment, etc. has changed from the MHz band to the GHz band. It is expected that in the future, requirements will be Material adaptability over a wide high frequency band.

Generally speaking, the transmission loss of electrical signals includes dielectric loss caused by the dielectric properties of the insulating layer surrounding the wiring, and conductor loss caused by the shape, surface resistance, characteristic impedance, etc. of the conductor. However, in the case of high-frequency circuits, the influence of dielectric loss is large and the dielectric loss becomes larger in proportion to the product of the square root of the relative permittivity of the material and the dielectric loss tangent of the material. Therefore, the relative dielectric loss is required. Materials with low electrical constant and dielectric loss tangent. Among them, the dielectric loss tangent is proportional to the dielectric loss and has a greater impact on the dielectric loss than the relative dielectric constant. Therefore, it is important to reduce the dielectric loss tangent.

For example, the following Patent Document 1 discloses a resin material containing A first compound having a naphthyl ether skeleton and a second compound having a skeleton derived from a dimer diamine or a trimer triamine, and the second compound is a compound different from the polyimide compound. Furthermore, it is disclosed that this resin material can reduce the dielectric loss tangent of the hardened material in a wide frequency band from low frequency band to high frequency band, and can effectively remove smear through the smear removal process.

[Prior art documents]

[Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2020-94212

In recent years, with the space-saving inside of electronic equipment, built-in parts such as printed wiring boards are assembled in a bent state, and therefore high flexibility is required.

Furthermore, along with the miniaturization and high performance of electronic components, the requirements for the thinning of circuits in printed wiring boards and the reliability of lines (wiring width)/space (wiring spacing) have become stricter. Therefore, the cured product of the adhesive resin sheet used between circuits also needs to have high migration resistance.

On the other hand, by switching to lead-free solder in the context of environmental protection, the temperature of the reflow process for packaging electronic components on printed wiring boards has increased. The cured product of the adhesive resin sheet is deteriorated by the heat of the reflow step, and the migration resistance may be significantly reduced.

Since the resin material described in Patent Document 1 has a rigid naphthalene skeleton, its bendability is impaired, and may break during the bending step. In addition, the heat resistance may not be sufficient, and the migration resistance after high-temperature treatment may not meet the requirements. The quality of migration.

The present disclosure is made in view of the above problems, and its purpose is to provide an adhesive resin sheet that has an excellent dielectric loss tangent in a high frequency band and is also durable after a reflow step at a high temperature (for example, 280° C.). It exhibits high migration resistance and good bending properties.

As a result of diligent research, the present inventors found that the subject of the present disclosure is solved in the following aspect, and completed the present disclosure. That is, the problem can be solved by providing an adhesive resin sheet, a printed wiring board having a cured product of the adhesive resin sheet, and an electronic device including the printed wiring board, the adhesive resin sheet being characterized by: When heated at 180°C for 1 hour, the following i, ii, iii and iv are satisfied.

i: at 23°C, the dielectric loss tangent at a frequency of 10GHz is less than 0.005; ii: at 23°C, the dielectric loss tangent at a frequency of 20GHz is less than 0.007; iii: at 23°C, at a frequency of 40GHz The dielectric loss tangent under the condition is less than 0.01; iv: Based on the thermogravimetric measurement specified in Japanese Industrial Standards (JIS) K7120, with inflow gas: nitrogen, measurement temperature range: 25℃~500℃, heating rate : The temperature at which the mass reduction rate measured at 10°C/min is 5% is 280°C or above.

Through the present disclosure, it is possible to provide an adhesive resin sheet that exhibits excellent dielectric loss tangent in each of the high frequency bands of 10 GHz, 20 GHz, and 40 GHz, does not deteriorate even in a high-temperature reflow step, and exhibits high Resistant to migration while having excellent bendability. This makes it possible to provide a printed wiring board and electronic equipment that does not malfunction even in high-frequency equipment and has high long-term reliability.

1:Polyimide membrane

2: Comb-type signal wiring for cathode electrode

2p: Cathode electrode connection point

3: Comb-type signal wiring for anode electrode

3p: Anode electrode connection point

4: Hardened material of adhesive resin sheet (adhesive layer)

5: Copper clad laminate

5a:Copper foil

5b: Insulation layer

ID-ID: line segment

FIG. 1A is a schematic plan view for explaining a method of manufacturing a laminated wiring board for evaluation of migration resistance in the present disclosure.

FIG. 1B is a schematic plan view for explaining a method of manufacturing a laminated wiring board for evaluation of migration resistance in the present disclosure.

FIG. 1C is a schematic plan view for explaining a method of manufacturing a laminated wiring board for migration resistance evaluation in the present disclosure.

1D is a schematic cross-sectional view for explaining a method of manufacturing a laminated wiring board for evaluating migration resistance in the present disclosure.

Hereinafter, an example of an embodiment to which the present disclosure is applied will be described. In addition, the dimensions and ratios of each member in the following figures are for convenience of explanation and are not limited to these. In addition, in this specification, the description of "any number A to any number B" means that the range includes number A as the lower limit and number B as the upper limit. In addition, in this specification, " "piece" includes not only "piece" defined in JIS, but also Also includes "membrane". In addition, numerical values specified in this specification are values obtained by methods disclosed in the embodiments or examples.

<<Adhesive resin sheet>>

The adhesive resin sheet of the present disclosure (hereinafter also referred to as the adhesive resin sheet) exhibits excellent dielectric loss tangent even in various high frequency bands such as 10 GHz, 20 GHz, and 40 GHz when heated at 180° C. for 1 hour. , has high migration resistance and high bendability after the reflow step. Therefore, this adhesive resin sheet is preferably used for adhesive members of printed wiring boards and electronic equipment. The adhesive resin sheet is temporarily adhered by being sandwiched between the members to be adhered, and then undergoes a heating or hot pressing step to harden and adhere the adherends to each other. In the following, the adhesive resin sheet heated at 180° C. for 1 hour will also be referred to as the cured product or adhesive layer of the adhesive resin sheet.

This adhesive resin sheet preferably contains a binder resin (A), a hardener (B), a filler (C) and other optional components.

<Binder resin (A)>

The binder resin (A) in the present disclosure preferably has a function of maintaining the dispersed state of other components in addition to functioning as a base of the adhesive resin sheet.

Examples of the binder resin (A) in the present disclosure include acrylic resin, polyester resin, polyurethane resin, polyurethane polyurea resin, polyamide resin, and polyimide resin. , polycarbonate resin, polyphenylene ether resin, styrene elastomer, fluororesin and styrene maleic anhydride resin, etc. These resins can be appropriately selected, and one type can be used alone or multiple types can be used in combination. Among them, it comes from highly hydrophobic From the viewpoint of high insulation, dielectric properties, and high heat resistance due to few thermal decomposition points, it is preferable to use styrene-based elastomer, polyphenylene ether, polyimide, etc. as the binder resin (A). Polyamide, polyurethane. In addition, from the same viewpoint, as the binder resin (A), it is more preferable to use a styrene-based elastomer, polyimide, polyamide, or polyurethane.

The styrenic elastomer refers to a block copolymer in which a portion including styrene and a portion including butadiene, isoprene, ethylene, or the like form a "block".

The adhesive resin (A) in the present disclosure preferably has functional groups such as epoxy group, maleimide group, isocyanate group, carbodiimide group or metal chelate that the hardener (B) can have. Reactive functional groups for compound reactions.

Examples of the reactive functional group include carboxyl group, acid anhydride group, hydroxyl group (alcoholic hydroxyl group, phenolic hydroxyl group), amine group, cyanate ester group, isocyanate group, cyanate group, isocyanate group, and imidazole group , pyrrolyl group, acetal group, acrylyl group, methacrylyl group, vinyl group, aldehyde group, hydrazine group, hydrazone group, phosphate group, etc. Wherein, the reactive functional group is preferably selected from the group consisting of carboxyl group, acid anhydride group, hydroxyl group (alcoholic hydroxyl group, phenolic hydroxyl group) and amine group. The binder resin (A) may contain two or more reactive functional groups in the molecular structure.

The binder resin (A) preferably has nitrogen atoms, phosphorus atoms, and sulfur atoms. By using a binder resin (A-i) containing elements containing non-shared electron pairs such as nitrogen, phosphorus, and sulfur, and by utilizing the interaction between the binder resin (A-i) of these non-shared electron pairs, it is possible to improve Adhere to the cohesiveness of the agent layer and inhibit the movement of ions, Therefore, migration resistance is further improved. In addition, the mechanism of the effect exerted by this disclosure is not limited to the content mentioned above.

When a binder resin (A-i) having a nitrogen atom, a phosphorus atom, and a sulfur atom and a binder resin (A-ii) not containing these atoms are used together as the binder resin (A), it is preferably as follows described.

That is, from the viewpoint of improving migration resistance, the mass ratio of the binder resin (A-i) in the entire binder resin (A) is preferably 30 mass % or more, more preferably 40 mass %. % or more, and more preferably 50 mass% or more. In addition, from the viewpoint of improving the surface adhesion force on the adherend without excessively increasing the cohesive force, it is preferable to set the mass ratio of the binder resin (A-i) to the entire binder resin (A) to 90 mass % or less, more preferably 80 mass % or less, still more preferably 70 mass % or less.

In addition, from the viewpoint of improving migration resistance, the mass ratio of the binder resin (A-ii) in the entire binder resin (A) is preferably 70 mass % or less, and more preferably 70 mass % or less. 60 mass % or less, more preferably 50 mass % or less. Furthermore, from the viewpoint of reducing the concentration of highly polar functional groups and suppressing water absorption of the adhesive resin sheet, it is preferable that the mass of the binder resin (A-ii) in the entire binder resin (A) is The ratio is set to 30% by mass or more.

The acid value of the binder resin (A) is preferably 0.5 mgKOH/g~30 mgKOH/g, more preferably 1.0 mgKOH/g~20 mgKOH/g. By setting the acid value to 0.5mgKOH/g~30mgKOH/g, the value of the dielectric loss tangent can be further reduced. By further improving the heat resistance, the migration resistance after the reflow step is further improved. good. In addition, these effects can be further obtained by setting the acid value to 1.0 mgKOH/g to 20 mgKOH/g.

From the viewpoint of reducing the dielectric loss tangent of the adhesive layer in the high-frequency band, the dielectric loss tangent of the adhesive resin (A) at 10 GHz, 20 GHz, and 40 GHz at 23°C is preferably 0.005 or less, and more preferably It is 0.004 or less, more preferably, it is 0.003 or less. Furthermore, the smaller the dielectric loss tangent of the binder resin (A) in each high frequency band, the better. Here, the dielectric loss tangent of the binder resin (A) is a value obtained by heating and curing only the binder resin (A) and measuring the dielectric loss tangent using the method described below.

Furthermore, from the viewpoint of reducing the dielectric loss tangent of the adhesive layer in a high-frequency band, the water absorption rate of the adhesive resin (A) according to the measurement method of JIS K7209 is preferably 0.5% or less. In addition, the lower the water absorption rate of the binder resin (A), the better.

From the viewpoint of improving the flexibility of the adhesive layer, the glass transition temperature (Tg) of the adhesive resin (A) is preferably 0°C to 140°C, more preferably 0°C to 120°C, and even more preferably 0°C to 120°C. 100℃.

The weight average molecular weight of the binder resin (A) is preferably 5,000 or more. When the weight average molecular weight of the binder resin (A) is 5,000 or more, sufficient film-forming properties can be easily demonstrated, and the decomposition temperature by weight can be increased by 5%, making the migration resistance after the reflow step even better. From the same viewpoint, the weight average molecular weight of the binder resin (A) is more preferably 20,000 or more. In addition, from the viewpoint of viscosity during coating or handling, the weight average molecular weight of the binder resin (A) is preferably 200,000 or less, more preferably 150,000 or less, and still more preferably 100,000 or less.

<Hardening agent (B)>

The hardening agent (B) preferably has a functional group capable of reacting with a reactive functional group that the binder resin (A) may have, and more preferably has a plurality of functional groups capable of reacting.

The hardener (B) is preferably selected from the group consisting of an epoxy group-containing compound (B-1), a maleimide group-containing compound (B-2), an isocyanate group-containing compound (B-3), and a metal chelate. At least one of the group consisting of the compound compound (B-4) and the carbodiimide group-containing compound (B-5). By using these hardeners, the heat resistance of the adhesive layer can be further improved, and the migration resistance after the reflow step can be further improved. The hardener can be used alone or in combination of two or more types.

[Epoxy group-containing compound (B-1)]

The epoxy group-containing compound (B-1) is not particularly limited as long as it has an epoxy group in the molecule. It can be preferably used if it has an average of two or more epoxy groups in one molecule. compound of. As the epoxy group-containing compound (B-1), for example, a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, and a cyclic aliphatic (alicyclic) ring type can be used. Oxygen resin and other epoxy resins.

Examples of the glycidyl ether type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD type epoxy resin, and cresol novolak type. Epoxy resin, phenol novolak type epoxy resin, α-naphthol novolak type epoxy resin, bisphenol A type novolak type epoxy resin, dicyclopentadiene type epoxy resin, tetrabromobisphenol A type Epoxy resin, brominated phenol novolak type epoxy resin, tris(glycidoxyphenyl)methane and tetrakis(glycidyloxyphenyl) Ethane etc.

Examples of the glycidylamine type epoxy resin include tetraglycidyldiaminodiphenylmethane, triglycidylp-aminophenol, triglycidylm-aminophenol, and tetraglycidylresorcinol. Methylamine etc.

Examples of the glycidyl ester type epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl tetrahydrophthalate, and the like.

Examples of the cyclic aliphatic (alicyclic) epoxy resin include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate.

As the epoxy group-containing compound (B-1), one type of the above-mentioned compounds may be used alone or two or more types may be used in combination.

As the epoxy group-containing compound (B-1), from the viewpoint of high adhesion, it is preferable to use bisphenol A-type epoxy resin, cresol novolak-type epoxy resin, or phenol novolak-type epoxy resin. , tris(glycidoxyphenyl)methane, tetrakis(glycidoxyphenyl)ethane or tetraglycidyl metaxylylenediamine. Moreover, from the viewpoint of heat resistance, the epoxy group-containing compound (B-1) is more preferably a compound containing a trifunctional or higher epoxy group.

[Maleimide group-containing compound (B-2)]

The maleimide group-containing compound (B-2) is not particularly limited as long as it is a compound having a maleimide group in the molecule, and a compound having an average of two maleimide groups in one molecule can be preferably used. More than one maleimide-based compound.

Specific properties of the maleimide group-containing compound (B-2) in the present disclosure Examples include: o-phenylene bismaleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, 4-methyl-1,3-phenylene Bismaleimide, N,N'-(toluene-2,6-diyl)bismaleimide, 4,4'-diphenylmethane bismaleimide, bisphenol A diphenyl Ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4,4'-diphenyl Ether bismaleimide, 4,4'-diphenylbismaleimide, 1,3-bis(3-maleimidephenoxy)benzene, 1,3-bis( 4-Maleimide phenoxy)benzene, polyphenylmethane maleimide (Chinese Academy of Sciences (CAS) number (NO): 67784-74-1, polymerization containing formaldehyde and aniline reaction product with maleic anhydride), N,N'-ethylidene bismaleimide, N,N'-trimethylene bismaleimide, N,N'-propylene bismaleimide Leimide, N,N'-tetramethylene bismaleimide, N,N'-pentamethylene bismaleimide, N,N'-(1,3-pentane di base) bis(maleimide), N,N'-hexamethylene bismaleimide, N,N'-(1,7-pentanediyl)bismaleimide, N ,N'-(1,8-octanediyl)bismaleimide, N,N'-(1,9-nonanediyl)bismaleimide, N,N'-(1 ,10-Decanediyl)bismaleimide, N,N'-(1,11-Undecanediyl)bismaleimide, N,N'-(1,12-12- Alkyldiyl)bismaleimide, N,N'-[(1,4-phenylene)bismethylene]bismaleimide, N,N'-[(1,2-phenylene) Phenyl)bismethylene]bismaleimide, N,N'-[(1,3-phenyl)bismethylene]bismaleimide, 1,6'-bismaleimide Imide-(2,2,4-trimethyl)hexane, N,N'-[(methylimino)bis(4,1-phenylene)]bismaleimide, N ,N'-(2-Hydroxypropane-1,3-diylbisiminobiscarbonylbisethyl)bismaleimide, N,N'-(dithiobisethyl)bismaleimide Leimide, N,N'-[hexamethylenebis(iminocarbonylmethylene)]bismaleimide, N,N'-carbonylbis(1,4-phenylene)bis malaysia Amine, N,N',N"-[nitrotris(ethylene)]trimaleimide, N,N',N"-[nitrotris(4,1-phenyl)]tris Maleimide, N,N'-[p-phenylenebis(oxy-p-phenylene)]bismaleimide, N,N'-[methylenebis(oxy)bis( 2-Methyl-1,4-phenylene)]bis(maleimide), N,N'-[methylenebis(oxy-p-phenylene)]bis(maleimide), N,N'-[Dimethylsilylbis[(4,1-phenylene)(1,3,4,-oxadiazole-5,2-diyl)(4,1-phenylene )]]Bismaleimide, N,N'-[(1,3-phenylene)dioxybis(3,1-phenylene)]bismaleimide, 1,1' -[3'-Oxospiro[9H-xanthene-9,1'(3'H)-isobenzofuran]-3,6-diyl]bis(1H-pyrrole-2,5-dione ), N,N'-(3,3'-dichlorobiphenyl-4,4'-diyl) bismaleimide, N,N'-(3,3'-dimethylbiphenyl- 4,4'-diyl)bismaleimide, N,N'-(3,3'-dimethoxybiphenyl-4,4'-diyl)bismaleimide, N, N'-[Methylenebis(2-ethyl-4,1-phenyl)]bismaleimide, N,N'-[Methylenebis(2,6-diethyl-4 ,1-phenyl)]bismaleimide, N,N'-[methylenebis(2-bromo-6-ethyl-4,1-phenyl)]bismaleimide , N,N'-[methylenebis(2-methyl-4,1-phenylene)]bismaleimide, N,N'-[ethylenebis(oxyethylene)] Bismaleimide, N,N'-[Sulfonylbis(4,1-phenylene)bis(oxy)bis(4,1-phenylene)]bismaleimide, N ,N'-[naphthalene-2,7-diylbis(oxy)bis(4,1-phenylene)]bismaleimide, N,N'-[p-phenylenebis(oxy) -p-phenylene)]bismaleimide, N,N'-[(1,3-phenylene)dioxybis(3,1-phenylene)]bismaleimide, N,N'-(3,6,9-trioxundecane-1,11-diyl)bismaleimide, N,N'-[isopropylidenebis[p-phenyleneoxy Carbonyl(p-phenyloxycarbonyl(p-phenyl)]]bismaleimide, N,N'-[isopropylidenebis[p-phenyloxycarbonyl(p-phenyl)]]bismaleimide , N,N'-[isopropylidenebis[(2,6-dichlorobenzene-4,1-diyl)oxycarbonyl (p-phenylene)]]bismaleimide, N,N '-[(phenylimino)bis(4,1-phenylene)]bismaleamide Amine, N,N'-[Azobis(4,1-phenylene)]bismaleimide, N,N'-[1,3,4-oxadiazole-2,5-diyl Bis(4,1-phenylene)]bismaleimide, 2,6-bis[4-(maleimide-N-yl)phenoxy]benzonitrile, N,N'-[ 1,3,4-oxadiazole-2,5-diylbis(3,1-phenylene)]bismaleimide, N,N'-[bis[9-oxo-9H-9 -Phospha(V)-10-oxaphenanthrene-9-yl]methylenebis(p-phenylene)]bismaleimide, N,N'-[hexafluoroisopropylidenebis[p- Phenyleneoxycarbonyl(m-phenylene)]]bismaleimide, N,N'-[carbonylbis[(4,1-phenylene)thio(4,1-phenylene) ]]Bismaleimide, N,N'-carbonylbis(p-phenyleneoxy p-phenylene)bismaleimide, N,N'-[5-tert-butyl-1, 3-phenylenebis[(1,3,4-oxadiazole-5,2-diyl)(4,1-phenylene)]]bismaleimide, N,N'-[phenyleneimide Cyclohexylbis(4,1-phenylene)]bismaleimide, N,N'-[methylenebis(oxy)bis(2-methyl-1,4-phenylene)] Bismaleimide, N,N'-[5-[2-[5-(dimethylamino)-1-naphthylsulfonamide]ethylaminemethyl]-1,3 -phenylene]bismaleimide, N,N'-(oxybisethylene)bismaleimide, N,N'-[dithiobis(m-phenylene)]bis Maleimide, N,N'-(3,6,9-trioxanodecane-1,11-diyl)bismaleimide, N,N'-(ethylidenebis- p-phenylene) bismaleimide; trade names manufactured by Designer Molecules: BMI-689, BMI-1500, BMI-1700, BMI-3000, BMI-5000, BMI-9000; JFE Chemicals Trade names manufactured by (JFE CHEMICAL): ODA-BMI, BAF-BMI and other polyfunctional maleimides.

Examples of the maleimide group-containing compound (B-2) include a polyfunctional maleimide obtained by reacting a polyfunctional amine with maleic anhydride. Examples of the polyfunctional amine include: isophorone diamine; dicyclohexylmethane-4,4'-diamine; terminally aminated polypropylene diamine manufactured by Huntsman Corporation. Trade names of alcohol skeleton: Jeffamine D-230, HK-511, D-400, XTJ-582, D-2000, XTJ-578, XTJ-509, XTJ-510, T-403, T-5000 ;Trade names with terminally aminated ethylene glycol backbone: XTJ-500, XTJ-501, XTJ-502, XTJ-504, XTJ-511, XTJ-512, Trade names of methyl glycol skeleton: XTJ-542, XTJ-533, XTJ-536, XTJ-548, XTJ-559, etc.

[Isocyanate group-containing compound (B-3)]

The isocyanate group-containing compound (B-3) is not particularly limited as long as it is a compound having an isocyanate group in the molecule.

Specific examples of the isocyanate group-containing compound (B-3) having one isocyanate group per molecule include n-butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, benzyl isocyanate, and (methyl) Acryloxyethyl isocyanate, 1,1-bis[(meth)acryloxymethyl]ethyl isocyanate, vinyl isocyanate, allyl isocyanate, (meth)acrylyl isocyanate, isopropenyl -α,α-dimethylbenzyl isocyanate, etc.

In addition, as the isocyanate group-containing compound (B-3), 1,6-diisocyanatohexane, isophorone diisocyanate, and 4,4'-diphenyl can also be used. Methane diisocyanate, polymeric diphenylmethane diisocyanate, xylylene diisocyanate, 2,4-tolylene diisocyanate (2,4-Tolylene Diisocyanate), toluene diisocyanate, 2,4-toluene diisocyanate (2,4-Toluene Diisocyanate), hexamethylene diisocyanate, 4-methyl-m-phenylene diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, tetramethyl-xylylene diisocyanate Isocyanate, cyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, cyclohexyl diisocyanate, benzidine diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethyl Diisocyanate compounds such as hexamethylene diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, and dimer diisocyanate are combined with vinyl monomers containing hydroxyl, carboxyl, and amide groups. Compounds obtained by equimolar reactions.

Specific examples of the isocyanate group-containing compound (B-3) having two isocyanate groups in one molecule include: 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-methylphenylene diisocyanate, 2,6-methylphenylene diisocyanate, 4,4'-methylphenylene diisocyanate Aniline diisocyanate, 2,4,6-toluene triisocyanate, 1,3,5-benzene triisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4',4" -Aromatic diisocyanates such as triphenylmethane triisocyanate; trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, Aliphatic diisocyanates such as 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecylethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate; ω ,ω'-diisocyanate-1,3-dimethylbenzene,ω,ω'-diisocyanate-1,4-dimethylbenzene,ω,ω'-diisocyanate-1,4-diethylbenzene, Aromatic aliphatic diisocyanates such as 1,4-tetramethylxylylene diisocyanate and 1,3-tetramethylxylylene diisocyanate; 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl Isocyanate [alias: isocyanate ketone diisocyanate], 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, -2,6-cyclohexane diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl) Alicyclic diisocyanates such as methyl)cyclohexane.

In addition, specific examples of the isocyanate group-containing compound (B-3) having three isocyanate groups in one molecule include aromatic polyisocyanates, aliphatic polyisocyanates such as lysate triisocyanate; aromatic aliphatic Polyisocyanate, alicyclic polyisocyanate, etc. Furthermore, specific examples include the trimethylolpropane adduct of diisocyanate described above, the biuret obtained by reacting with water, and the trimer having an isocyanurate ring.

As the isocyanate group-containing compound (B-3), the isocyanate group among the various isocyanate group-containing compounds exemplified can also be used through ε-caprolactam or methyl ethyl ketone (MEK) oxime, etc. Protected blocked isocyanate group-containing compounds.

Specifically, isocyanates of the isocyanate group-containing compound using ε-caprolactam, methyl ethyl ketone (hereinafter also referred to as MEK) oxime, cyclohexanone oxime, pyrazole, phenol, etc. Compounds obtained by blocking groups, etc. In particular, in the present disclosure, when a hexamethylene diisocyanate trimer having an isocyanurate ring and blocked with MEK oxime or pyrazole is used, it is very preferable since it has excellent heat resistance. Moreover, from the viewpoint of heat resistance, the isocyanate group-containing compound (B-3) preferably has a trifunctional or higher isocyanate group.

[Metal chelate compound (B-4)]

The metal chelate compound (B-4) is an organic metal compound containing a metal and an organic substance, and reacts with the reactive functional group of the binder resin (A) to form a crosslink. The type of organic metal compound is not particularly limited, and examples thereof include organic aluminum compounds, organic titanium compounds, organic zirconium compounds, and the like. In addition, the bond between the metal and the organic substance may be a metal-oxygen bond, and is not limited to a metal-carbon bond. In addition, the bonding method between metal and organic matter can be any of chemical bonding, coordination bonding, and ionic bonding. Furthermore, from the viewpoint of heat resistance, the organometallic compound is preferably trifunctional or higher.

The organoaluminum compound is preferably an aluminum metal chelate compound. Examples of aluminum metal chelate compounds include aluminum diisopropyl ethyl acetate acetate, aluminum tris(ethyl acetyl acetate), aluminum diisopropyl alkyl acetyl acetate, and bis(monoacetyl acetate acetate). Aluminum ethyl acetate acetate, aluminum tris(acetyl acetate), aluminum bis(ethyl acetate acetate) monoacetate, aluminum di-n-butanol monomethyl acetyl acetate, diisobutanol monomethyl ethyl acetate Aluminum acetyl acetate, aluminum di-butoxide monomethyl acetyl acetate, aluminum isopropoxide, aluminum diisopropyl mono-butoxide, aluminum ethoxide, aluminum ethoxide, etc.

The organic titanium compound is preferably a titanium metal chelate compound. Examples of the titanium metal chelate compound include titanium acetylpyruvate, titanium tetraacetylpyruvate, titanium ethyl acetyl acetate, titanium octanedioxide, titanium ethyl acetyl acetate, and 1,3-propanedioxy. Titanium bis(ethyl acetyl acetate), polyacetyl titanium acetyl acetate, tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetraoctyl titanate Ester, tert-pentyl titanate, tetra-tert-butyl titanate, tetrastearyl titanate, titanium isostearate, tri-n-butoxy titanium monostearate, di-isopropyl titanate Oxytitanium distearate, titanium stearate, di- Titanium isopropoxide diisostearate, (2-n-butoxycarbonylbenzoyloxy)titanium tributoxide, etc.

The organic zirconium compound is preferably a zirconium metal chelate compound. Examples of zirconium metal chelate compounds include zirconium tetraacetylpyruvate, zirconium tributoxyacetylpyruvate, zirconium monobutoxyacetylpyruvate bis(ethylacetylacetate), and dibutoxyzirconium acetylpyruvate. Bis(ethyl acetyl acetate) zirconium, tetraacetyl zirconium acetate, n-propyl zirconate, n-butyl zirconate, zirconium stearate, zirconium octanoate, etc.

Among these, the metal chelate compound (B-4) is preferably an organic titanium compound or an organic zirconium compound in terms of thermosetting reactivity.

[Carbodiamide group-containing compound (B-5)]

The carbodiimide group-containing compound (B-5) is not particularly limited as long as it is a compound having a carbodiimide group in the molecule. Examples of the carbodiimide group-containing compound (B-5) include Carbodilite V-01, V-03, V-05, V-07, and V-09 (trade name, Nisshinbo Chemical Co., Ltd.), cyclic carbodiimide (Teijin Co., Ltd.), etc. From the viewpoint of heat resistance, the carbodiimide group-containing compound (B-5) preferably has an average of three or more carbodiimide groups in one molecule.

In this adhesive resin sheet, the content of the hardener (B) is preferably 1 to 30 parts by mass in total based on 100 parts of the binder resin (A). By setting the added amount of the hardener (B) in the adhesive resin sheet to 1 to 30 parts by mass, the polar group content derived from the hardener (B) contained in the adhesive resin sheet can be reduced. , it is easy to suppress the dielectric loss tangent lower. In addition, as mentioned above By controlling the amount of hardener (B) added, it is easy to control the glass transition temperature (Tg) of the adhesive layer within a preferable range, and it is easy to achieve the coexistence of high flexibility and low dielectric loss tangent. . From the same point of view, the content of the hardener (B) in the adhesive resin sheet is more preferably 1 to 20 parts by mass based on 100 parts of the adhesive resin (A), and further preferably 1 to 10 parts by mass. parts by mass.

The functional group equivalent of the hardener (B) is preferably 50g/eq~1,000g/eq, more preferably 50g/eq~500g/eq, further preferably 50g/eq~300g/eq. By setting the functional group equivalent within these ranges, sufficient crosslinking density can be easily obtained, and high heat resistance can be easily expressed. In addition, by setting the functional group equivalent within the above range, the polar group content derived from the hardener (B) contained in the adhesive resin sheet can be easily controlled, and the dielectric loss tangent can be easily reduced.

In addition, from the viewpoint of improving heat resistance, the curing agent (B) preferably has an aromatic structure in its structure.

<Filling (C)>

Next, the filler (C) used in the present disclosure will be described in detail. From the viewpoint of increasing the decomposition temperature by 5% and improving the migration resistance after the reflow step, the adhesive resin sheet preferably contains a filler (C).

The filler (C) is not particularly limited, and examples of the shape include spherical, powdery, fibrous, needle-like, scaly, and the like.

Examples of the filler (C) include polytetrafluoroethylene powder or modified products thereof, tetrafluoroethylene-perfluoroalkyl vinyl ether powder, tetrafluoroethylene-ethylene powder, tetrafluoroethylene-hexafluoropropylene powder, tetrafluoroethylene-hexafluoropropylene powder, tetrafluoroethylene-perfluoroalkyl vinyl ether powder, Vinyl fluoride-vinylidene fluoride powder, tetrafluoroethylene-hexafluoropropylene- Perfluoroalkyl vinyl ether powder, polychlorotrifluoroethylene powder, chlorotrifluoroethylene-ethylene powder, chlorotrifluoroethylene-vinylidene fluoride powder, polyvinylidene fluoride powder, polyvinylidene fluoride powder and other fluorine fillers ;Polyethylene powder, polyacrylate powder, epoxy resin powder, polyamide powder, polyimide powder, polyurethane powder, liquid crystal polymer, polysiloxane powder, etc., and the use of silicone , acrylic, styrene butadiene rubber, butadiene rubber and other multi-layered core-shell polymer fillers; melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, amide phosphate Ammonium, ammonium polyphosphate, phosphate urethane, polyphosphate urethane and other (poly)phosphate compounds, organic phosphate compounds, phosphazene compounds, phosphonic acid compounds, diethylphosphine Aluminum phosphate, aluminum methylethylphosphinate, aluminum diphenylphosphinate, aluminum ethylbutylphosphinate, aluminum methylbutylphosphinate, aluminum polyethylenephosphinate and other phosphinic acid compounds, Phosphorus fillers such as phosphine oxide compounds, phosphorane compounds, and phosphatidamide compounds; benzoguanamine, melamine, melam, melem, melon, and melamine cyanide Nitrogen fillers such as urea ester, cyanuric acid compound, isocycyanuric acid compound, triazole compound, tetrazole compound, diazo compound, urea, etc.; silica or hollow silica or porous silica , mica, talc, kaolin, clay, hydrotalcite, wollastonite, anhydrite, silicon nitride, boron nitride, aluminum nitride, calcium hydrogen phosphate, calcium phosphate, glass flakes, hydrated glass, titanium Calcium acid, sepiolite, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, hydrogen Barium oxide, calcium hydroxide, titanium oxide, tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, antimony oxide, nickel oxide, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, boric acid Aluminum and other inorganic fillers, etc.

From the viewpoint of reducing the dielectric loss tangent in addition to the migration resistance after the reflow step, the filler (C) is preferably selected from the group consisting of fluorine-based fillers, boron nitride, liquid crystal polymers, and silicon dioxide. and at least one of phosphorus fillers. In addition, from the same viewpoint, as the filler (C), it is more preferable to use at least one selected from the group consisting of fluorine-based fillers, boron nitride, phosphorus-based fillers, and silica. Since these fillers have a solid crystal structure, their molecular vibrations are small at high frequencies and their dielectric loss tangent is excellent. In the present disclosure, the filler (C) can be used alone or in combination. Furthermore, in this disclosure, the so-called liquid crystal polymer refers to a granular substance.

Relative to the total mass of the adhesive resin sheet, the content of the filler (C) in the adhesive resin sheet is preferably 3% to 50% by mass, more preferably 4% to 30% by mass, and particularly preferably 8% by mass. %~25% by mass. By containing 3% by mass or more of filler (C) in this adhesive resin sheet, the thermal stability of the adhesive layer is increased, and voids caused by decomposition of the adhesive layer due to the heat of the reflow step can be reduced. , whereby migration resistance can be easily improved. Furthermore, by setting the content of the filler (C) to 3% by mass or more, the effect of reducing the dielectric loss tangent is also achieved. In addition, from these viewpoints, the content of the filler (C) is more preferably 4% by mass or more, and particularly preferably 8% by mass or more. By setting the content of the filler (C) to 50 mass % or less, the flexibility of the adhesive layer can be further improved. In addition, from the same viewpoint, the content of the filler (C) is more preferably 30 mass% or less, and particularly preferably 25 mass% or less.

From the viewpoint of the dielectric loss tangent, the dielectric loss tangent of the filler (C) at 10 GHz at 23° C. is preferably 0.005 or less, more preferably 0.004 or less, and still more preferably 0.003 or less. The smaller the dielectric loss tangent of the filler (C), the better.

The average particle diameter D ₅₀ of the filler (C) is preferably 0.1 μm to 25 μm. When the average particle diameter D ₅₀ of the filler (C) is 0.1 μm to 25 μm, improvement in coating properties can be expected. In addition, from the same viewpoint, the average particle diameter D ₅₀ of the filler (C) is more preferably 1.0 μm to 10 μm.

The method of adding the filler (C) is not particularly limited, and any conventionally known method can be used. Specific examples of this addition method include: a method of adding the filler (C) to the polymerization reaction liquid before or during polymerization of the binder resin (A); adding the filler (C) to the binder resin using a three-roller mill, etc. A method of kneading the filler (C) in (A); a method of preparing a dispersion containing the filler (C) and mixing the dispersion into the binder resin (A), etc. In addition, in order to disperse the filler (C) well and stabilize the dispersion state, a dispersant, a tackifier, etc. may be used within a range that does not affect the physical properties of the adhesive resin sheet.

<Other additives>

In addition, energy ray absorbers, dyes, pigments, antioxidants, polymerization inhibitors, defoaming agents, leveling agents, and ion traps may be added to the adhesive resin sheet within the scope that does not impair the purpose. agents, moisturizers, viscosity adjusters, preservatives, antibacterial agents, antistatic agents, anti-adhesive agents, infrared absorbers, electromagnetic wave shielding agents, etc. as optional ingredients. In addition, from the viewpoint of improving laser processability, it is preferable to blend an energy ray absorber into the adhesive resin sheet.

<Dielectric loss tangent of adhesive resin sheet>

The cured product of the adhesive resin sheet in the present disclosure has (i) a dielectric loss tangent of 0.005 or less at a measured frequency of 10 GHz at 23°C, (ii) a dielectric loss tangent of 0.007 or less at a measured frequency of 20 GHz, and (iii) ) The dielectric loss tangent at a measured frequency of 40GHz is 0.01 or less.

By setting the dielectric loss tangent within the numerical range, the transmission loss of electrical signals in electronic components is improved.

In particular, in recent years, the transition to information communication and transmission using signals in the sub6G band (3.6GHz ~ 6GHz) and millimeter wave bands (28GHz ~ 300GHz) has been promoted in electronic equipment. Accordingly, the cured product (adhesive layer) of the adhesive resin sheet of the present disclosure used in the electronic device satisfies the above-mentioned (i), (ii), and (iii) for improving adjacent circuits. The transmission loss of electrical signals has a significant effect.

As mentioned above, from the viewpoint of the transmission loss of electrical signals, the dielectric loss tangent of the adhesive layer is 0.005 or less at 23° C. and a measurement frequency of 10 GHz, preferably 0.004 or less, and more preferably 0.003 or less, especially The best value is less than 0.002.

In addition, from the viewpoint of transmission loss of electrical signals, the dielectric loss tangent of the adhesive layer is 0.007 or less at 23° C. and a measurement frequency of 20 GHz, preferably 0.006 or less, more preferably 0.005 or less, and particularly preferably Below 0.004.

Furthermore, from the viewpoint of transmission loss of electric signals, the dielectric loss tangent of the adhesive layer is 0.010 or less at 23° C. and a measurement frequency of 40 GHz, preferably 0.008 or less, still more preferably 0.007 or less, and particularly preferably Below 0.006.

Furthermore, the smaller the dielectric loss tangent of the adhesive layer at each measurement frequency, the better good.

The dielectric loss tangent of the adhesive layer in this disclosure (hereinafter also referred to as this adhesive layer) can be controlled by the type of adhesive resin (A). From the viewpoint of easily achieving the dielectric loss tangent within the above range, the binder resin (A) is preferably a styrene elastomer, polyimide, polyamide or polyurethane.

In the adhesive layer that satisfies the specific dielectric loss tangent in the present disclosure, in addition to using the specific adhesive resin mentioned above, the content of the hardener (B) or the functional group equivalent, the filler (C) This is achieved by controlling the content and dielectric loss tangent of filler (C).

<5% weight decomposition temperature of adhesive resin sheet>

The thermal stability of this adhesive layer can be determined by a measurement method based on the thermogravimetric measurement method specified in JIS K7120. The adhesive layer obtained by heating the adhesive resin sheet at 180° C. for 1 hour satisfies the following condition (iv). That is, (iv) the temperature at which the mass reduction rate is 5% measured based on the thermogravimetric measurement specified in JIS K7120 with inflow gas: nitrogen, measurement temperature range: 25°C to 500°C, and heating rate: 10°C/min. (hereinafter also referred to as the 5% weight decomposition temperature) is 280°C or above. The 5% weight decomposition temperature in this specification is defined as the temperature at which the weight decreases by 5% due to temperature rise when the weight of the adhesive layer before measurement is 100%. Since the 5% weight decomposition temperature of this adhesive layer is 280°C or higher, it is possible to reduce the reflow step, which is one of the electronic component packaging steps of the printed wiring board that is an application example of this adhesive resin sheet and other aspects of this disclosure. volatile components (emitted gases). In addition, delamination and bubbling (bubbling) caused by thermal expansion of outgassed gas can be suppressed. and improve the migration resistance after the reflow step. From the same viewpoint, the 5% weight decomposition temperature of this adhesive layer is preferably 290°C or higher, more preferably 300°C or higher. In addition, from the viewpoint of increasing the efficiency of incineration in the disposal of printed wiring boards, the 5% weight decomposition temperature of the adhesive layer is preferably 500°C or lower, more preferably 450°C or lower.

The 5% weight decomposition temperature of this adhesive layer can be controlled by controlling the amount of filler (C) added or changing the type of binder resin (A), using a binder resin (A) with a specific molecular weight, or using a specific structure (aromatic). Family structure) hardener (B), adjust the functional group equivalent of the hardener (B), etc. to control.

<Glass transition temperature (Tg) of the cured product of the adhesive resin sheet>

The glass transition temperature (Tg) of the cured product (adhesive layer) of this adhesive resin sheet is preferably 0°C to 150°C. If the Tg of this adhesive layer is 0° C. or higher, the dielectric loss tangent of the adhesive layer can be further reduced. In addition, from the same viewpoint, the Tg of this adhesive layer is more preferably 40°C or higher, and further preferably 70°C or higher. If the Tg of this adhesive layer is 150°C or less, the flexibility of the adhesive layer can be further improved. In addition, from the same viewpoint, the Tg of this adhesive layer is more preferably 120°C or lower, and further preferably 100°C or lower.

Next, a method for determining Tg of this adhesive layer will be described. The Tg of this adhesive layer can be measured using a dynamic viscoelasticity analysis method (DVA method) measuring device or the like. From the viscoelastic curve related to the adhesive layer obtained by this device, the ratio of storage elastic modulus/loss elastic modulus (tan δ) at each temperature can be determined, and the maximum point of the tan δ curve can be determined. The point is taken as the Tg of this adhesive layer. In addition, when there are a plurality of maximum points in the tan δ curve, the highest maximum point is set as the Tg of this adhesive layer. The Tg of this adhesive layer can be controlled by the glass transition temperature of the adhesive resin (A) and the amount of the hardener (B).

<Manufacturing method of adhesive resin sheet>

The manufacturing method of this adhesive resin sheet is not specifically limited, For example, the following method can be used. First, a coating solution containing a binder resin (A), a hardener (B), a filler (C), other optional components, and a solvent is applied to one side of the release film. Next, a liquid medium such as an organic solvent contained in the coating solution is usually removed and dried at 40°C to 150°C to form an adhesive resin sheet. Furthermore, an adhesive resin sheet with release films on both sides can also be produced by laminating another release film on the surface of the obtained adhesive resin sheet. By laminating the adhesive resin sheet with release films on both sides, surface contamination of the adhesive resin sheet can be prevented. Furthermore, the adhesive resin sheet can be separated by peeling off the release film.

The two peeling films can be of the same type or of different types. In addition, by using release films with different releasability on both sides of the adhesive resin sheet, the release force can be enhanced, making it easier to peel off the sheets in sequence during use.

As the coating method of the coating solution, for example, notch wheel coating, knife coating, die coating, lip coating, roller coating, curtain coating, rod coating, gravure printing, and flexographic printing can be selected. , screen printing, dip coating, spray coating, spin coating and other well-known methods.

From the perspective of exerting sufficient adhesiveness and ease of handling, the thickness of the adhesive resin sheet after drying is preferably 5 μm to 500 μm, more preferably 10μm~100μm.

<Use of adhesive resin sheets and adhesive resin sheets with release films>

This adhesive resin sheet etc. can be used to obtain a copper-clad laminated board or a printed wiring board. In other words, this adhesive resin sheet can be used for copper-clad laminate applications or printed wiring board applications. In addition, they are explained in detail below.

<Copper Clad Laminated Board>

The copper-clad laminated board is a laminate in which a copper foil and an insulating film are laminated via an adhesive that is a cured product of the adhesive resin sheet.

Such a copper-clad laminated board can be obtained by the following method, for example. That is, the release film can be peeled off in sequence from the adhesive resin sheet with the release film, and the copper foil and the insulating film can be stacked on each side of the adhesive resin sheet (this step is also called temporary adhesion). Then, the obtained laminated body is subjected to a heating or hot pressing step to thermally harden the adhesive resin sheet between the copper foil and the insulating film, thereby obtaining the copper-clad laminated board.

Alternatively, a copper-clad laminate can also be obtained by the following method. It is also possible to apply a coating solution for forming an adhesive resin sheet on an insulating film and dry it. Then, a copper foil is stacked on the formed adhesive resin sheet, and the copper foil is heated or hot-pressed to insulate the copper foil. The adhesive resin sheets between the films are thermally cured to obtain a copper-clad laminate.

A copper-clad laminated board can have both outermost layers made of copper foil like copper foil/adhesive layer/insulating film/adhesive layer/copper foil, or it can also have an inner layer of copper foil. When a copper foil or an insulating film is laminated using a plurality of adhesive resin sheets, the plurality of adhesive resin sheets may be heated and cured once after temporary adhesion several times.

<Printed wiring board>

The printed wiring board in this disclosure (hereinafter also referred to as this printed wiring board) contains a cured product of this adhesive resin sheet.

For example, the copper foil in the copper-clad laminate described above can be processed by etching to form a signal circuit or a ground circuit, thereby obtaining a printed wiring board. In addition, the release film can also be peeled off from the adhesive resin sheet with the release film, and the adhesive resin sheet can be bonded to the circuit surface and heated and cured to protect the signal circuit or be used as a base for further multilayering.

As a method of setting up a signal circuit or a ground circuit, for example, the following method can be used. First, a photosensitive etching resist layer is formed on the copper foil of the copper-clad laminate, exposed through a mask film having a circuit pattern, and only the exposed portion is cured. Next, the unexposed portions of the copper foil are removed by etching, and then the remaining resist layer is peeled off, thereby forming a conductive circuit from the copper foil.

In addition, this printed wiring board can also be produced without using the copper-clad laminated board mentioned above.

For example, printing technology can also be used to form a conductor pattern on a flexible, insulating plastic film such as polyester, polyimide, liquid crystal polymer, or polytetrafluoroethylene (PTFE) film. Thereafter, a protective layer is laminated with the adhesive resin sheet interposed so as to cover the conductor pattern, and the adhesive resin sheet is heated and pressurized to harden the adhesive resin sheet, thereby obtaining a flexible printed wiring provided with the protective layer. plate.

Alternatively, sputtering or plating can also be used on a flexible, insulating plastic film. Only necessary circuits are provided by applying or other methods, and a flexible printed wiring board provided with a protective layer via the cured product of the adhesive resin sheet is obtained in the same manner.

Furthermore, the adhesive resin sheet can be sandwiched between a plurality of flexible printed wiring boards and heated and pressed to harden the adhesive resin sheet, thereby using the adhesive resin sheet for interlayer bonding. Resin sheet. In this way, a multilayer flexible printed wiring board and the like can also be obtained.

This printed wiring board may be provided with through-hole openings such as blind holes or through holes in order to provide conduction between an adhesive layer obtained by curing the adhesive resin sheet or a plurality of copper foils arranged with a protective layer sandwiched between them. The via opening is usually formed by laser processing using laser light or drilling processing using a drill. Among these, from the viewpoint of improving the shape accuracy of the through-hole opening, it is preferable to form the through-hole opening by laser processing.

This printed wiring board can be used to manufacture various electronic devices such as smartphones, tablet terminals, and cameras. That is, the electronic device in this disclosure includes this printed wiring board.

[Example]

Hereinafter, the present disclosure will be explained in more detail through examples, but the present disclosure is not limited to the following examples. In addition, unless otherwise specified, "part" in the examples means "mass part", and "%" means "mass %".

In addition, the acid value of the resin was measured using the following method.

"Acid value of binder resin (A)"

The acid value of the binder resin (A) is measured based on JIS K0070. Specifically, about 1 g of the sample was accurately measured in a co-plugged Erlenmeyer flask, and 100 ml of a tetrahydrofuran/ethanol (volume ratio: tetrahydrofuran/ethanol=2/1) mixed solution was added and dissolved. to it Add phenolphthalein test solution as an indicator, titrate with 0.1N alcoholic potassium hydroxide solution, and set the end point when the indicator remains light red for 30 seconds. The acid value is calculated by the following formula (unit: mgKOH/g).

Formula (1) acid value (mgKOH/g)=(5.611×a×F)/S

S: Sample collection amount (g)

a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)

F: titer of 0.1N alcoholic potassium hydroxide solution

"Measurement of weight average molecular weight (Mw) of binder resin (A)"

For the measurement of the weight average molecular weight (Mw), a gel permeation chromatograph (GPC) brand name: "HPC-8020" manufactured by Tosoh Co., Ltd. was used. GPC is a liquid chromatography device that separates and quantifies substances dissolved in a solvent (THF; tetrahydrofuran) based on differences in their molecular sizes. In this measurement, two product names: "LF-604" (manufactured by Showa Denko Co., Ltd.: GPC column for rapid analysis: 6mmID The column temperature is 40°C, and the weight average molecular weight (Mw) is determined based on polystyrene conversion.

"Measurement of the average particle size D ₅₀ of filler (C)"

The average particle diameter D ₅₀ of the filler (C) was determined using a laser diffraction-scattering particle size distribution measuring device, trade name: LS13320 (manufactured by Beckman Coulter), and using a cyclone to dry the powder sample mold. The value is measured using a Tornado dry powder sample module, and is the particle size at which the cumulative value in the cumulative particle size distribution is 50%. Furthermore, the refractive index is set to 1.6.

"Material: Binder resin (A)"

(A-1): Styrenic elastomer, trade name: FG1901GT (maleic acid-modified styrenic elastomer), acid value 10 mgKOH/g, weight average molecular weight 95,000, Tg 80°C (Clayton ( Made by Clayton Company).

(A-2): Polyimide resin, acid value 9 mgKOH/g, weight average molecular weight 45,000, Tg 50°C (manufactured by TOYOCHEM Co., Ltd.)

(A-3): Polyamide resin, acid value 10.6 mgKOH/g, weight average molecular weight 21,000, Tg 55°C (manufactured by TOYOCHEM Co., Ltd.)

(A-4): Polyurethane resin, acid value 10 mgKOH/g, weight average molecular weight 120,000, Tg 25°C (manufactured by TOYOCHEM Co., Ltd.)

(A-5): Polyester resin, brand name: Vylon 637, acid value 5 mgKOH/g, weight average molecular weight 30,000, Tg 21°C (manufactured by Toyobo Co., Ltd.)

"Material: Hardener (B)"

(B-1): Trade name: YX-8800 (glycidyl ether type epoxy resin, functional group equivalent 180 g/eq, bifunctional), manufactured by Mitsubishi Chemical Corporation

(B-2): Trade name: MIR-3000 (biphenyl aralkyl maleimide resin, functional group equivalent 275g/eq), manufactured by Nippon Chemical Co., Ltd.

(B-3): Trade name: TKA-100 (isocyanurate type isocyanate compound, Functional group equivalent: 180g/eq, trifunctional), manufactured by Asahi Kasei Co., Ltd.

(B-4): Trade name: Orgatix ZC-150 (organic zirconium oxide compound, functional group equivalent 122 g/eq, tetrafunctional), manufactured by Matsumoto Fine Chemical Co., Ltd.

(B-5): Trade name: Carbodilite V-05 (carbodiamide group-containing compound, functional group equivalent: 262 g/eq, multifunctional), manufactured by Nisshinbo Chemical Co., Ltd.

(B-6): Trade name: BAPP (polyamine group-containing compound, functional group equivalent 205 g/eq, bifunctional), manufactured by SEIKA

"Raw materials: filler (C)"

(C-1): Trade name: SC2050-MB (silica, average particle diameter D ₅₀ : 0.5 μm), manufactured by Admatechs

(C-2): Trade name: SP-2 (boron nitride, average particle diameter D ₅₀ : 4.0 μm), manufactured by Denka Corporation

(C-3): Trade name: KT-300 (fluorine-based filler, average particle diameter D ₅₀ : 10.0 μm), manufactured by Kitamura Co., Ltd.

(C-4): Trade name: E101-S (liquid crystal polymer, average particle diameter D ₅₀ : 17.5 μm), manufactured by Sumitomo Chemical Co., Ltd.

(C-5): Trade name: EXOLIT OP935 (aluminum phosphinate salt, average particle diameter D ₅₀ : 2.5 μm), manufactured by Clariant Corporation

(C-6): Trade name: HT grade (alumina, average particle size D ₅₀ : 1.2 μm), manufactured by Tokuyama Corporation

[Example 1]

<<Manufacturing of coating liquid>>

In terms of solid content, put 100 parts of binder resin (A-1), 5 parts of hardener (B-1), and 10 parts of filler (C-1) into a container so that the non-volatile content concentration becomes 30%. Add the mixed solvent (toluene: MEK=9:1 (mass ratio)) and stir for 10 minutes using a disperser to obtain a coating liquid.

<<Manufacturing of adhesive resin sheets>>

The obtained coating liquid was evenly applied to a 50 μm thick heavy release film (polyethylene terephthalate (PET) coated with a heavy release agent) using a doctor blade so that the thickness after drying would be 25 μm. film) and dried at 100°C for 2 minutes. Thereafter, the adhesive resin sheet is cooled to room temperature (for example, 25° C.) to obtain an adhesive resin sheet with a release film on one side. Next, the adhesive resin sheet surface of the obtained adhesive resin sheet with a release film on one side was overlapped with a light release film (polyethylene terephthalate (PET) film coated with a light release agent) with a thickness of 50 μm. )superior. Then, an adhesive resin sheet with release films on both sides including a heavy release film/adhesive resin sheet/light release film was obtained.

According to the method described below, the dielectric loss tangent at 10 GHz, 20 GHz, and 40 GHz, the 5% weight decomposition temperature in a nitrogen atmosphere, and the glass transition temperature (Tg) were measured for the cured product of the adhesive resin sheet. In addition, the migration resistance and bendability of the laminated wiring board A using the adhesive resin sheet were evaluated according to the method described below. The evaluation results are shown in Tables 1 to 3.

<Dielectric loss tangent at 10GHz, 20GHz, and 40GHz>

Prepare 4 adhesive resin sheets with release films on both sides produced by the above method, peel off the release films one by one, overlap the exposed adhesive resin sheets with each other, and laminate 4 sheets in total using a vacuum laminator (Nikki Lamination is performed using a small pressurized vacuum laminator V-130 (trade name) manufactured by Nichigo-Morton. At this time, the outermost release films on both sides are not peeled off and remain as they are. As a result, an adhesive resin sheet with a release film on both sides including four adhesive resin sheets and a 100 μm-thick adhesive resin sheet sandwiched between a heavy release film and a light release film was obtained. In addition, the vacuum lamination conditions were performed at a heating temperature of 90° C., a vacuum time of 60 seconds, a vacuum reaching pressure of 2 hPa, a pressure of 0.4 MPa, and a pressurization time of 60 seconds.

Next, the adhesive resin sheet with release films on both sides was pressed at 180° C. and 2 MPa for 1 hour, the release film was peeled off, and the cured product of the adhesive resin sheet was used as a test piece for measurement. The test piece for measurement is stored in an environment of 23°C and a relative humidity of 50% for more than 24 hours, and then the dielectric constant is determined by the cavity resonator method using a dielectric constant measuring device manufactured by AET Corporation in this temperature and humidity environment. Measure the dielectric loss tangent at a frequency of 10GHz. At the measurement frequencies of 20 GHz and 40 GHz, the same test piece was measured using resonators with corresponding frequencies.

<Glass transition temperature (Tg)>

(Preparation of adhesive layer for measurement)

The coating liquid used in each Example and each Comparative Example was evenly applied to a heavy release film (polyethylene terephthalate coated with a heavy release agent) with a thickness of 50 μm using a doctor blade so that the thickness after drying would be 200 μm. diester (PET) film) and dried at 100°C for 2 minutes. Thereafter, it is cooled to room temperature (for example, 25°C) to form a single-sided tape with peeling Film adhesive resin sheet.

Next, the adhesive resin sheet surface of the obtained adhesive resin sheet with a release film on one side was overlapped with a light release film (polyethylene terephthalate (PET) film coated with a light release agent) with a thickness of 50 μm. ), an adhesive resin sheet with release films on both sides including a heavy release film/adhesive resin sheet/light release film was obtained.

The obtained adhesive resin sheet with release films on both sides was thermally cured at 180° C., 1 hour, and 2 MPa, and the heavy release film and the light release film were peeled off to obtain an adhesive layer of 200 μm.

(Measurement of glass transition temperature (Tg))

A test piece for measurement cut out from the obtained adhesive layer in a size of 5 mm × 30 mm was cooled to 0°C using a dynamic viscoelasticity measuring device, trade name: "DVA200" (manufactured by IT Measurement Control Co., Ltd.). , heated to 300°C at a heating rate of 10°C/min, and measured viscoelasticity at a vibration frequency of 10Hz.

The storage elastic modulus is obtained from the obtained viscoelastic curve, and the loss tangent (tan δ) is calculated at each temperature based on the loss elastic modulus, and the point at which the tan δ curve becomes a maximum is calculated and set to Tg. . In addition, when there are a plurality of maximum points, the value with the highest temperature is set as the tan δ peak value (Tg) of the hardened material.

<Migration resistance>

The evaluation method of migration resistance will be described with reference to FIGS. 1A to 1D .

First, a laminated body of a copper foil with a thickness of 12 μm and a polyimide film with a thickness of 25 μm was etched. Then, as shown in the schematic plan view of Figure 1A, lines/spaces of 0.05mm/0.05mm including cathode electrodes are formed on the polyimide film 1. The cathode electrode comb-shaped signal wiring 2 at the pole connection point 2p and the anode electrode comb-shaped signal wiring 3 including the anode electrode connection point 3p.

Next, as shown in the schematic plan view of FIG. 1B , the comb-type signal wiring 2 for the cathode electrode and the comb-type signal wiring 3 for the anode electrode shown in FIG. 1A are covered, with the vicinity of the cathode electrode connection point 2p and the anode electrode connection point 3p Attach an adhesive resin sheet with release films on both sides so that the surrounding area is exposed. Specifically, the surface of an adhesive resin sheet with a release film on both sides, from which the light release film has been peeled off, is attached to the above-mentioned portion and temporarily adhered using a vacuum laminator. Thereafter, the releasable film of the adhesive resin sheet is peeled off, and the copper-clad laminate 5 (CCL) including the copper foil 5a and the insulating layer 5b is attached thereon. Specifically, the insulating layer 5b of the copper-clad laminated board 5 is temporarily bonded with the adhesive resin sheet before curing by using a vacuum laminator, and then hot pressed at 180° C., 1 hour, 2 MPa. Thermal curing was performed to obtain a laminated wiring board A for evaluation in which single-sided CCL was arranged on the adhesive layer (cured product 4 of the adhesive resin sheet). A schematic plan view of the produced laminated wiring board for evaluation is shown in FIG. 1C , and a schematic cross-sectional view when the laminated wiring board for evaluation in FIG. 1C is cut along line ID-ID is shown in FIG. 1D .

Next, the obtained laminated wiring board A for evaluation was subjected to solder float processing. The polyimide film 1 of the laminated wiring board A for evaluation was floated face down in molten solder at 288° C. for 10 seconds, and the sample (laminated wiring board A for evaluation) was taken out.

Thereafter, the anode electrode was connected to the anode electrode connection point 3p and the cathode electrode was connected to the cathode electrode connection point 2p in an environment with a temperature of 85°C and a relative humidity of 85% RH (relative humidity). Voltage 50V, and lasts for 1000 hours. Then, the change in resistance value until 1000 hours has passed was continuously measured. Furthermore, the so-called "leak touch" means that there is insulation damage caused by a short circuit, and the resistance is instantly reduced and current flows. In the absence of leakage contact, insulation will not be degraded. The evaluation criteria regarding migration resistance are as follows.

A: The resistance value after 1000 hours is 1.0×10 ¹⁰ Ω or more and the number of leakage contacts is 0 times.

B: The resistance value after 1000 hours is 1.0×10 ⁸ Ω or more and the number of leakage contacts is 1, or the resistance value after 1000 hours is 1.0×10 ⁸ Ω or more and less than 1.0×10 ¹⁰ Ω and the leakage current contact is The number of stream contacts is 0.

C: The resistance value after 1000 hours is 1.0×10 ⁷ Ω or more and the number of leakage contacts is 2, or the resistance value after 1000 hours is 1.0×10 ⁷ Ω or more but less than 1.0×10 ⁸ Ω and the leakage current contact is The number of stream contacts is less than 1.

D: The resistance value after 1000 hours is less than 1.0×10 ⁷ Ω, or the number of leakage contacts is more than 3 times.

<Flexibility>

The produced adhesive resin sheet with release films on both sides was peeled off the light release film and vacuum laminated to a circuit board with line/space = 0.05mm/0.05mm. Thereafter, the laminated wiring board A for evaluation was produced according to the same procedure as the evaluation of migration resistance.

For this laminated wiring board A, perform the following operations: bend the copper-clad laminated board 5 at 180 degrees on the outside, place a weight of 500g on the bent part for 5 seconds, and then return the bent part to its original position. In the flat state, place the 500g weight again for 5 seconds, and set this operation to the number of bends once. Then, for the adhesive layer 4 The bending portion to which a load of 500 g was applied was counted and the number of times it was bent until cracks occurred was evaluated based on the following criteria.

In addition, whether cracks have occurred is confirmed by cutting the laminated wiring board A with a razor and observing its cross section using a microscope manufactured by KEYENCE Co., Ltd. (trade name: "VHX-900"). .

A: More than 5 times.

B: More than 3 times but less than 5 times.

C: More than 2 times but less than 3 times.

D: Less than 2 times.

<5% weight decomposition temperature in nitrogen atmosphere (heat resistance evaluation)>

The 5% weight decomposition temperature of the hardened material (adhesive layer) of the adhesive resin sheet produced in the same manner as the dielectric loss tangent measurement was measured using trade name: TGDTA220 (manufactured by Seiko Instruments). In addition, the measurement is based on the thermogravimetric measurement method specified in JIS K7120. Specifically, an aluminum open sample pan was used, and the measurement was carried out under the conditions of 5 mg of sample (adhesive layer), nitrogen flow rate of 200 mL of air per minute, starting temperature of 25°C, and heating rate of 10°C per minute, until 500 to ℃.

Then, based on the obtained results, the following formula (2) is used to calculate the weight change of the sample. The temperature is plotted on the horizontal axis and the weight change is plotted on the vertical axis. The temperature that causes a 5% weight change is set to 5%. Gravimetric decomposition temperature.

Formula (2) Weight change (%) = weight at each temperature (g)/weight of hardened material before measurement (g) × 100

The obtained 5% weight decomposition temperature was evaluated based on the following evaluation criteria, and the heat resistance of the adhesive layer was evaluated.

A: Above 300℃.

B: Above 290℃, less than 300℃.

C: Above 280℃ and below 290℃.

D: Less than 280℃.

[Example 2 to Example 24, Comparative Example 1 to Comparative Example 3]

As shown in Tables 1 to 3, an adhesive resin sheet was obtained in the same manner as in Example 1, except that the types or amounts of the binder resin (A), hardener (B), and filler (C) were changed. to evaluate.

This application claims priority based on Japanese Patent Application No. 2021-121487 filed on July 26, 2021, and the entire contents of the disclosure are incorporated into this application.

[Industrial availability]

The cured product of this adhesive resin sheet can achieve a lower dielectric loss tangent in high frequency bands (10GHz, 20GHz, 40GHz), and furthermore, can exhibit high migration resistance and excellent bending properties after the reflow step. Therefore, this adhesive resin sheet can be suitably used for manufacturing printed wiring boards, electronic equipment, etc. which require high reliability or flexibility.

1:Polyimide membrane

2: Comb-type signal wiring for cathode electrode

3: Comb-type signal wiring for anode electrode

4: Hardened material of adhesive resin sheet (adhesive layer)

5: Copper clad laminate

5a:Copper foil

5b: Insulation layer

Claims (10)

An adhesive resin sheet, which satisfies the following i, ii, iii, and iv when heated at 180° C. for 1 hour, and contains an adhesive resin sheet selected from the group consisting of acrylic resin, polyurethane resin, and polyurethane resin. Binder resins in acid ester polyurea resin, polyamide resin, polyimide resin, polycarbonate resin, polyphenylene ether resin, styrene elastomer, fluororesin and styrene maleic anhydride resin, and Hardener, which does not contain a modified elastomer with an acid anhydride group and a solvent-soluble polyimide resin at the same time; i: at 23°C, the dielectric loss tangent at a frequency of 10GHz is less than 0.005; ii: at 23°C , the dielectric loss tangent at the measured frequency of 20GHz is less than 0.007; iii: at 23°C, the dielectric loss tangent at the measured frequency of 40GHz is less than 0.01; iv: based on the thermogravimetric measurement specified in Japanese Industrial Standard K7120, The temperature when the mass reduction rate is 5% measured with inflow gas: nitrogen, measurement temperature range: 25°C~500°C, and heating rate: 10°C/min is 280°C or above. The adhesive resin sheet according to claim 1, wherein the glass transition temperature when heated at 180°C for 1 hour is 0°C to 150°C. The adhesive resin sheet according to claim 1 further contains a filler, and the content of the filler is 50% by mass or less based on the total mass of the adhesive resin sheet. The adhesive resin sheet as described in claim 2 further contains a filler, relatively The content of the filler is 50% by mass or less based on the total mass of the adhesive resin sheet. The adhesive resin sheet according to claim 3, wherein the filler includes at least one selected from the group consisting of fluorine-based fillers, boron nitride, liquid crystal polymers, silicon dioxide, and phosphorus-based fillers. The adhesive resin sheet according to claim 1, wherein the adhesive resin has an element selected from the group consisting of nitrogen atoms, phosphorus atoms, and sulfur atoms. The adhesive resin sheet according to claim 1, wherein the hardener comprises an epoxy group-containing compound, a maleimide group-containing compound, an isocyanate group-containing compound, a metal chelate compound, and a carbon-containing compound. Compounds of diimide-based compounds. The adhesive resin sheet according to any one of claims 1 to 7 is used for printed wiring boards. A printed wiring board having a cured product of the adhesive resin sheet according to claim 8. An electronic device including the printed wiring board according to claim 9.

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