JP2021017461A - Prepreg, insulation base material, conductor substrate, and wiring board - Google Patents

Abstract

To provide a prepreg that can reduce the stress developed between a wiring board and an electronic component, and an insulation substrate obtained from the same.SOLUTION: Disclosed is a prepreg 10 containing glass cloth 3, and an elastic resin 1 with which the glass cloth 3 is impregnated. The elastic resin 1 is a curable resin composition that contains a rubber component, an epoxy resin, and an epoxy resin curing agent.SELECTED DRAWING: Figure 2

Description

The present invention relates to prepregs, insulating substrates, conductor substrates, and wiring substrates.

As the insulating resin constituting the wiring substrate, a polymer material such as a polymer acrylic polymer which is a copolymer of a (meth) acrylic acid alkyl ester and a monomer having a crosslinkable functional group may be used (Patent Documents). 1).

Japanese Unexamined Patent Publication No. 2016-79367

One aspect of the present invention provides a prepreg and an insulating substrate obtained from the prepreg, which can relieve the stress generated between the wiring board and the electronic component.

One aspect of the present invention relates to a prepreg containing a glass cloth and an elastic resin impregnated in the glass cloth. The stretchable resin is a curable resin composition containing a rubber component, an epoxy resin, and a curing agent for the epoxy resin.

Another aspect of the present invention relates to an insulating base material containing a glass cloth and an elastic resin impregnated in the glass cloth. The stretchable resin is a cured product of a curable resin composition containing a rubber component, an epoxy resin, and a curing agent for the epoxy resin.

Yet another aspect of the present invention relates to a conductor substrate comprising the insulating substrate and a conductor layer provided on the insulating substrate.

Yet another aspect of the present invention relates to a wiring board including a laminate having two or more insulating substrates and wiring layers provided on one or both sides of the laminate. The insulating base material arranged on the outermost layer of the laminated body is the insulating base material containing a stretchable resin.

One aspect of the present invention provides a prepreg and an insulating substrate obtained from the prepreg, which can relieve the stress generated between the wiring board and the electronic component.

It is a stress-strain curve which shows the measurement example of the recovery rate. It is a schematic diagram which shows one Embodiment of the method of manufacturing a prepreg. It is a schematic diagram which shows one Embodiment of the method of manufacturing a wiring board. It is a schematic diagram which shows one Embodiment of the method of manufacturing a wiring board.

Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

The prepreg according to the embodiment includes a glass cloth and an elastic resin impregnated in the glass cloth. The stretchable resin is a curable resin composition containing a rubber component, an epoxy resin, and a curing agent for the epoxy resin. By curing the curable resin composition, an insulating base material containing a stretchable resin which is a cured product of the curable resin composition is formed.

The elastic resin is a resin that exhibits rubber elasticity. For example, the recovery rate after tensile deformation of a sheet-shaped elastic resin to a strain of 20% is 80% or more. This recovery rate is determined by a tensile test using a test piece of elastic resin molded into a sheet shape. The strain (displacement amount) applied to the test piece in the first tensile test is X, and the difference between the position and X at the time when the test piece starts to be loaded when the test piece is returned to the initial position and the tensile test is performed again. When Y, the recovery rate is calculated by the formula: R (%) = (Y / X) × 100. The recovery rate can be measured with X as 20%. FIG. 1 is a stress-strain curve showing a measurement example of the recovery rate. The recovery rate may be 85% or more, or 90% or more. The upper limit of the recovery rate is 100%.

The tensile elastic modulus of the stretchable resin may be 0.1 MPa or more and 1000 MPa or less, 0.3 MPa or more and 100 MPa or less, or 0.5 MPa or more and 50 MPa or less. The elongation at break of the stretchable resin may be 100% or more. When the elongation at break is 100% or more, the stress between the wiring board and the electronic component is likely to be relaxed more effectively. From the same viewpoint, the elongation at break may be 150% or more, 200% or more, 300% or more, or 500% or more. The upper limit of the elongation at break is not particularly limited, but is usually about 1000% or less. The tensile elastic modulus and the elongation at break of the stretchable resin are measured by a tensile test using a test piece cut out from the stretchable resin formed into a sheet.

The dielectric loss tangent (Df) of the stretchable resin may be 0.004 or less. When the dielectric loss tangent is 0.004 or less, the transmission loss of the wiring pattern provided on the insulating base material tends to be sufficiently reduced. From the same viewpoint, the dielectric loss tangent of the stretchable resin may be 0.0035 or less, 0.003 or less, or 0.0025 or less. The lower limit of the dielectric loss tangent is not particularly limited, but is usually about 0.0005 or more.

The relative permittivity (Dk) of the stretchable resin may be 4.0 or less. When the relative permittivity is 4.0 or less, the transmission loss of the wiring pattern provided on the insulating base material tends to be sufficiently reduced. From this point of view, the relative permittivity may be 3.5 or less, 3.0 or less, or 2.5 or less.

The curable resin composition constituting the stretchable resin and the cured product thereof contain a rubber component. This rubber component mainly imparts elasticity to the elastic resin.

The rubber component may include rubber having a cross-linking group. By using a rubber having a cross-linking group, the heat resistance of the stretchable resin tends to be easily improved. The cross-linking group is a reactive group capable of cross-linking the molecular chain of the rubber component by the reaction between the cross-linking groups and / or the reaction between the cross-linking group and the epoxy resin. Examples thereof include acid anhydride groups, carboxyl groups, amino groups, hydroxyl groups, and epoxy groups.

The rubber component may contain a rubber having at least one cross-linking group of an acid anhydride group or a carboxyl group. Examples of rubbers having an acid anhydride group include maleic anhydride-modified elastomer, which is a polymer containing a monomer unit derived from maleic anhydride. The maleic anhydride-modified elastomer may be a maleic anhydride-modified styrene-based elastomer or a maleic anhydride-modified hydrogenated styrene-based elastomer. As a commercially available product of the maleic anhydride-modified styrene-based elastomer, for example, there is a styrene-based elastomer "Toughprene 912" manufactured by Asahi Kasei Corporation. The maleic anhydride-modified hydrogenated styrene-based elastomer can contribute to the improvement of the weather resistance of the stretchable resin. The hydrogenated styrene-based elastomer is an elastomer obtained by adding hydrogen to an unsaturated double bond of a styrene-based elastomer having a soft segment containing an unsaturated double bond. Examples of hydrogenated styrene-based elastomers include maleic anhydride-modified styrene / ethylene / butylene / styrene block copolymers. Examples of commercially available maleic anhydride-modified hydrogenated styrene elastomers include Kraton Polymer Japan Co., Ltd.'s "FG1901", "FG1924", "FG1924GT", Asahi Kasei Co., Ltd.'s "Tough Tech M1911", "Tough Tech M1913", There is "Tough Tech M1943".

Other examples of rubber components include acrylic rubber, isoprene rubber, butyl rubber, styrene butadiene rubber, butadiene rubber, acrylonitrile butadiene rubber, silicone rubber, urethane rubber, chloroprene rubber, ethylene propylene rubber, fluororubber, rubber sulfide, epichlorohydrin rubber, And chlorinated butyl rubber. From the viewpoint of protecting the wiring from damage due to moisture absorption or the like, the rubber component may contain at least one selected from styrene-butadiene rubber, butadiene rubber, and butyl rubber.

The weight average molecular weight of the rubber component may be 20000 to 20000, 30000 to 150,000, or 50000 to 125000 from the viewpoint of coating film property. The weight average molecular weight (Mw) here means a standard polystyrene-equivalent value determined by gel permeation chromatography (GPC).

The content of the rubber component in the curable resin composition or the stretchable resin may be 60 to 95% by mass based on the total amount of the rubber component, the epoxy resin and the curing agent. When the content of the rubber component is 60% by mass or more, the stretchable resin tends to have a larger stretchability. When the content of the rubber component is 95% by mass or less, the stretchable resin tends to have particularly excellent properties in terms of adhesion, insulation reliability, and heat resistance. From the same viewpoint, the content of the rubber component may be 65 to 90% by mass, or 70 to 85% by mass.

The curable resin composition constituting the stretchable resin contains an epoxy resin and a curing agent thereof. A crosslinked polymer is formed by the reaction of the epoxy resin and the curing agent, whereby the curable resin composition is cured.

Epoxy resin is a compound having an epoxy group. The epoxy resin may be monofunctional, bifunctional or polyfunctional, but in order to obtain sufficient curability, a bifunctional or higher functional epoxy resin may be used.

Examples of epoxy resins include bisphenol A type, bisphenol F type, phenol novolac type, naphthalene type, dicyclopentadiene type, and cresol novolac type epoxy resins. The epoxy resin may have a fat chain. The epoxy resin having a fat chain can impart flexibility to the stretchable resin. Examples of commercially available epoxy resins having a fat chain include EXA-4816 manufactured by DIC Corporation. From the viewpoint of curability, low tack property, and heat resistance, a phenol novolac type, a cresol novolac type, a naphthalene type, or a dicyclopentadiene type epoxy resin may be selected. These epoxy resins can be used alone or in combination of two or more.

By combining a rubber having at least one cross-linking group of an acid anhydride group or a carboxyl group with an epoxy resin, the heat resistance of the stretchable resin, low moisture permeability, adhesion to the conductive layer, and tack reduction are achieved. Therefore, a particularly excellent effect can be obtained. When the heat resistance of the stretchable resin is improved, deterioration of the stretchable resin in a heating step such as nitrogen reflow can be suppressed. When the stretchable resin has a low tack, it is possible to handle an insulating substrate, a conductor substrate, or a wiring substrate with good workability.

The curable resin composition may contain a crosslinkable component other than the epoxy resin as long as the gist of the present invention is not deviated. The content of the cross-linking component other than the epoxy resin may be less than 10 parts by mass with respect to 100 parts by mass of the epoxy-based resin from the viewpoint of more sufficiently reducing the dielectric loss tangent of the elastic resin.

The curing agent may contain an ester-based curing agent having an active ester group. The ester-based curing agent can reduce the dielectric loss tangent while improving the heat resistance of the stretchable resin.

式中、Ｒ^１、Ｒ^２及びＲ^３はそれぞれ独立に、１価の有機基を示し、芳香環を有する１価の有機基であってもよい。 The ester-based curing agent reacts with the epoxy resin, for example, as represented by (I) below. According to this reaction, no hydroxyl group is generated by ring opening of the epoxy group. Therefore, the curable resin composition containing the epoxy resin and the ester-based curing agent can form a cured product in which the absorption peak attributed to the expansion and contraction vibration of the hydroxyl group is not observed in the infrared absorption spectrum.

In the formula, R ¹ , R ² and R ³ each independently represent a monovalent organic group and may be a monovalent organic group having an aromatic ring.

As the ester-based curing agent, the activity formed from the carboxylic acid and the phenol, thiophenol, N-hydroxyamine, or heterocyclic hydroxy compound from the viewpoint of more sufficiently obtaining the effect of improving the heat resistance and the effect of reducing the dielectric tangent. Examples include compounds having an ester group. Examples of commercially available ester-based curing agents include "EPICLON HPC8000-65T", "EPICLON HPC8000-L-65MT", and "EPICLON HPC8150-60T" (all trade names manufactured by DIC Corporation). These can be used alone or in combination of two or more.

The equivalent ratio of the epoxy group in the epoxy resin to the ester bond in the ester-based curing agent may be in the range of 4: 5 to 5: 4. When the equivalent ratio is within this range, the stretchable resin tends to have particularly excellent properties in terms of adhesion, insulation reliability, and heat resistance.

The total content of the epoxy resin and the curing agent may be 5 to 40% by mass, 10 to 35% by mass, or 15 to 30% by mass based on the total amount of the rubber component, the epoxy resin and the curing agent. .. When the total content of the epoxy resin and the curing agent is 5% by mass or more, it is easy to obtain sufficient curing, and the stretchable resin has particularly excellent properties in terms of adhesion, insulation reliability, and heat resistance. Tends to have. When the total content of the epoxy resin and the curing agent is 40% by mass or less, more sufficient elasticity tends to be obtained, and the rubber component and the epoxy resin tend to be mixed well.

The curable resin composition may contain an ester-based curing agent and a curing agent other than the ester-based curing agent. In that case, the content of the other curing agent may be less than 10 parts by mass with respect to 100 parts by mass of the ester-based curing agent from the viewpoint of more sufficiently reducing the dielectric loss tangent of the stretchable resin.

The curable resin composition may further contain a curing accelerator. The curing accelerator is a compound that functions as a catalyst for the curing reaction. The curing accelerator may be at least one selected from tertiary amines, imidazoles, organic acid metal salts, phosphorus compounds, Lewis acids, amine complex salts and phosphine. Among these, imidazole may be used from the viewpoint of storage stability and curability of the curable resin composition. When the rubber component contains a maleic anhydride-modified elastomer, imidazole compatible with the maleic anhydride-modified elastomer may be selected.

The content of the curing accelerator may be 0.1 to 10 parts by mass with respect to 100 parts by mass of the total amount of the rubber component, the epoxy resin and the curing agent. When the content of the curing accelerator is 0.1 parts by mass or more, more sufficient curing tends to be obtained. When the content of the curing accelerator is 10 parts by mass or less, more sufficient heat resistance tends to be obtained. From the same viewpoint, the content of the curing accelerator may be 0.3 to 7 parts by mass or 0.5 to 5 parts by mass.

In addition to the above components, the curable resin composition contains, if necessary, an antioxidant, an antioxidant, an ultraviolet absorber, a visible light absorber, a colorant, a plasticizer, a stabilizer, a filler, and a flame retardant. , Leveling agent and the like may be further contained as long as the effects of the present invention are not significantly impaired.

FIG. 2 is a schematic diagram showing an embodiment of a method for producing a prepreg. In the method shown in FIG. 2, the glass cloth 3 is sandwiched between the elastic resins 1A and 1B in the form of films from both sides, and the laminate composed of the elastic resin 1A, the glass cloth 3 and the elastic resin 1B is heated and pressurized. This includes obtaining the glass cloth 3 and the prepreg 10 containing the stretchable resin 1 impregnated in the glass cloth 3. For example, the laminate may be heated to about 90 ° C. while pressurizing under vacuum. By curing the elastic resins 1A and 1B by heating and pressurizing, an insulating base material containing a glass cloth and a cured product of the curable resin composition can also be obtained. The proportion of the stretchable resin 1 in the prepreg or the insulating base material may be 30 to 80% by mass based on the mass of the prepreg or the insulating base material. The thickness of the glass cloth 3 may be 100 μm or less, or 50 μm or less.

The prepreg 10 can also be obtained by impregnating a glass cloth with a resin varnish containing a rubber component, an epoxy resin and a curing agent, and an organic solvent in which these are dissolved or dispersed, and then removing the solvent from the varnish. In this case, the proportion of the organic solvent remaining in the stretchable resin in the prepreg 10 may be less than 80% by mass. The drying temperature for removing the organic solvent may be 80 to 180 ° C.

The film-shaped elastic resins 1A and 1B can be used to obtain a resin varnish by dissolving or dispersing, for example, a rubber component, an epoxy resin, a curing agent, and if necessary, other components in an organic solvent, and forming a film of the resin varnish. It can be produced by a method including forming on a carrier film and removing an organic solvent from a resin varnish.

Examples of organic solvents constituting the resin varnish include aromatic hydrocarbons such as toluene, xylene, mesityrene, cumene and p-simene; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; acetone, methyl ethyl ketone and methyl isobutyl ketone, Ketones such as cyclohexanone and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; N , N-Dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and other amides. Toluene or N, N-dimethylacetamide may be used from the viewpoint of solubility and boiling point. These organic solvents can be used alone or in combination of two or more. The concentration of the solid content (components other than the organic solvent) in the resin varnish may be 20 to 80% by mass based on the mass of the resin varnish.

Examples of carrier films include polyester (eg polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate), polyolefin (eg polyethylene, polypropylene), polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, polyethersulfide, Examples include films of polyethersulfone, polyetherketone, polyphenylene ether, polyphenylene sulfide, polyarylate, polysulfone, or liquid crystal polymers. Among these, from the viewpoint of flexibility and toughness, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, polyallylate, or polysulfone film is used. It may be used as a carrier film.

The thickness of the carrier film is not particularly limited, but may be 3 to 250 μm. When the thickness of the carrier film is 3 μm or more, the film strength is sufficient, and when the thickness of the carrier film is 250 μm or less, sufficient flexibility can be obtained. From the above viewpoint, the thickness may be 5 to 200 μm or 7 to 150 μm. From the viewpoint of improving the peelability from the stretchable resin layer, a film obtained by releasing the base film with a silicone-based compound, a fluorine-containing compound, or the like may be used, if necessary.

A protective film may be further provided on the elastic resins 1A and 1B formed on the carrier film. The protective film may be, for example, a film of polyester (for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate) or polyolefin (polyethylene, polypropylene). The surface of the protective film may be surface-treated with a mold release agent of a silicone compound or a fluorine-containing compound. The thickness of the protective film is not particularly limited, but may be 10 to 250 μm.

The conductor substrate according to the embodiment includes an insulating base material and a conductor layer provided on the insulating base material. The insulating base material includes a stretchable resin which is a cured product of the curable resin composition and a glass cloth. The conductor layer is provided on one or both sides of the insulating base material. The conductor substrate can be used, for example, to manufacture a wiring board described later.

The conductor layer can be a conductor foil or a conductor plating film. The thickness of the conductor layer may be, for example, 1 to 50 μm.

The conductor foil may be a metal foil, and examples thereof include copper foil, titanium foil, stainless steel foil, nickel foil, permalloy foil, 42 alloy foil, coval foil, nichrome foil, beryllium copper foil, and phosphorus brass foil. Brass foil, white foil, aluminum foil, tin foil, lead foil, zinc foil, solder foil, iron foil, tantalum foil, niobium foil, molybdenum foil, zirconium foil, gold leaf, silver foil, palladium foil, monel foil, inconel foil, Hastelloy Examples include foil. From the viewpoint of appropriate elastic modulus and the like, the conductor foil may be copper foil, gold leaf, nickel foil, or iron foil. From the viewpoint of wiring formability, the conductor foil may be a copper foil.

The metal foil may have a roughened surface formed by the roughening treatment. In this case, the metal foil is usually provided on the insulating base material with the roughened surface in contact with the insulating base material. From the viewpoint of adhesion between the insulating base material (particularly the elastic resin) and the metal foil, the surface roughness Ra of the roughened surface may be 0.1 to 3 μm or 0.2 to 2.0 μm. The surface roughness Ra of the roughened surface may be 0.3 to 1.5 μm in order to easily form fine wiring.

The surface roughness Ra can be measured under the following conditions using, for example, a surface shape measuring device Wyko NT9100 (manufactured by Veeco).
Measurement conditions Internal lens: 1x External lens: 50x Measurement range: 0.120 x 0.095mm
Measurement depth: 10 μm
Measurement method: Vertical scanning interference method (VSI method)

A conductor substrate having an insulating base material and a conductor foil can be obtained, for example, by a method of heating and pressurizing a laminate formed by laminating a conductor foil on a prepreg.

The conductor plating film can be formed by a usual plating method used in an additive method or a semi-additive method. For example, after performing a plating catalyst application treatment to attach palladium, the insulating base material is immersed in an electroless plating solution to form an electroless plating layer (conductor layer) having a thickness of 0.3 to 1.5 μm on the entire surface of the primer. Precipitate. If necessary, electrolytic plating (electroplating) can be further performed to adjust the thickness to the required value. As the electroless plating solution used for electroless plating, any electroless plating solution can be used, and there is no particular limitation. The usual method can be adopted for electrolytic plating, and there is no particular limitation. The conductor plating film (electroless plating film, electrolytic plating film) may be a copper plating film from the viewpoint of cost and resistance.

The wiring board according to one embodiment includes an insulating base material laminate having two or more insulating base materials, and a wiring layer provided on one side or both sides of the insulating base material laminate. Among the insulating base material laminates, the insulating base material arranged at least in the outermost layer is an insulating base material containing a glass cloth and an elastic resin.

3 and 4 are schematic views showing an embodiment of a method for manufacturing a wiring board and an electronic component device. The method shown in FIGS. 3 and 4 was obtained by laminating the copper foil 30, the prepreg 10, the core base material 20, the prepreg 10, and the copper foil 30 in this order ((a) in FIG. 3). By heating and pressurizing the laminate, the curable resin composition which is a stretchable resin in the prepreg 10 is cured to form the laminate 40 with a copper foil ((b) in FIG. 3), and the copper foil. Part of 30 is removed to form the outer wiring layer 31, thereby obtaining the wiring board 41 ((c) in FIG. 4), and connecting the chip 50 to the wiring layer 31 via the solder 55. To obtain the electronic component device 100 ((d) in FIG. 4).

The core base material 20 has a core insulating base material 5 and an internal wiring layer 7 provided on both surfaces of the core insulating base material 5. The internal wiring layer 7 can be a conductor foil or a conductor plating film similar to the conductor layer described above. The core insulating base material 5 contains a glass cloth and an insulating resin impregnated therein. The insulating resin constituting the core insulating base material 5 can be a non-stretchable resin. The recovery rate of the non-stretchable resin measured by the above method may be 50% or less, 40% or less, 30% or less, or 0% or more. The insulating resin of the core insulating base material 5 may be an elastic resin.

The heating and pressurizing conditions for forming the copper foil-attached laminate 40 are set so that the layers are in close contact with each other and the curable resin composition (stretchable resin) in the prepreg 10 is sufficiently cured. For example, a laminate 40 with a copper foil can be obtained by press molding at 180 ° C.

The outer wiring layer 31 is formed by patterning the copper foil 30 of the laminated body 40 with the copper foil. As a method for patterning the copper foil 30, ordinary photolithography can be applied.

The wiring board 41 is provided on both sides of the core insulating base material 5 and the insulating base material laminate 15 composed of the insulating base material 10A laminated on both sides of the core insulating base material 5, and the inside provided on both sides of the core insulating base material 5. It is composed of a wiring layer 7 and an outer wiring layer 31 provided on both sides of the insulating base material laminate 15. The insulating base material 10A arranged on the outermost layers on both sides of the insulating base material laminate 15 contains a glass cloth and a stretchable resin. Since the insulating base material 10A arranged in the outermost layer of the insulating base material laminate 15 contains an elastic resin, the stress between the wiring board 41 and the electronic component (here, the chip 50) mounted on the wiring board 41 is effective. Can be relaxed.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

1. 1. Production Example 1 of Resin Varnish
80 parts by mass of a toluene solution (concentration 25% by mass) of maleic anhydride-modified styrene ethylene butadiene rubber (manufactured by KRATON Co., Ltd., trade name "FG1924GT") and a dicyclopentadiene type epoxy resin (manufactured by DIC Co., Ltd., trade name "EPICLIN") 11.1 parts by mass of a toluene solution (concentration 25% by mass) of "HP7200H") and a toluene solution (manufactured by DIC Co., Ltd., trade name "HPC8000-65T", dicyclopentadiene type diphenol compound) Concentration 25% by mass) 8.9 parts by mass and 1-benzyl-2-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., trade name "1B2MZ") are mixed with 3 parts by mass, and the mixture is stirred to obtain a resin varnish. It was.

2. 2. Preparation of film-shaped stretchable resin A polyethylene terephthalate (PET) film (manufactured by Teijin DuPont Film Co., Ltd., trade name "Purex A31", thickness 25 μm) having a release surface was prepared as a carrier film. The resin varnish was applied onto the release surface of this PET film using a knife coater (manufactured by Yasui Seiki Co., Ltd., trade name "SNC-350"). The coating film was dried in a dryer (manufactured by Futaba Kagaku Co., Ltd., trade name "MSO-80TPS") at 100 ° C. for 20 minutes to form a film-like elastic resin having a thickness of 15 μm. A PET film having the same release surface as the carrier film was attached to the formed elastic resin as a protective film with the release surface facing the resin layer side to obtain a laminated film.

3. 3. Preparation of Insulating Base Material Two laminated films were prepared, and the protective film was peeled off from each laminated film. The two exposed film-like elastic resins were laminated on the upper surface and the lower surface of an IC cloth for a printed circuit board (glass cloth, thickness 27 μm, manufactured by Unitika Ltd., model number “# 1037”), respectively. Next, using a vacuum pressurizing laminator (manufactured by Nikko Materials Co., Ltd., trade name "V130"), a film-like elastic resin under the conditions of a pressure of 0.5 MPa, a temperature of 90 ° C., and a pressurization time of 60 seconds. Was laminated on both sides of the IC cloth. Then, the stretchable resin was cured by heating at 180 ° C. for 60 minutes in a dryer (manufactured by Futaba Kagaku Co., Ltd., trade name “MSO-80TPS”). As a result, an insulating base material (thickness of about 50 μm) having a stretchable resin and a glass cloth, which are cured products of the curable resin composition, was obtained.

4. Evaluation 4-1. Tensile test A strip-shaped test piece having a length of 40 mm and a width of 10 mm was cut out from the insulating base material. A tensile test of this test piece was carried out using an autograph (manufactured by Shimadzu Corporation, trade name "EZ-S") to obtain a stress-strain curve. From the obtained stress-strain curve, the tensile elastic modulus and the elongation at break were determined. The tensile test was performed under the conditions of a distance between chucks of 20 mm and a tensile speed of 50 mm / min. The tensile modulus was determined from the slope of the stress-strain curve in the stress range of 0.5 to 1.0 N. The strain at the time when the test piece broke was recorded as the elongation at break. The results are shown in Table 1.

4-2. Relative permittivity (Dk) and dielectric loss tangent (Df)
A test piece having a size of 80 mm × 80 mm was prepared from the insulating base material. Using this test piece, Dk and Df were calculated by the cavity resonator method. Vector network analyzer E8364B (manufactured by Keysight Technology Co., Ltd.), CP531 (manufactured by Kanto Denshi Applied Development Co., Ltd.) and CPMA-V2 (program) are used as measuring instruments, respectively, and the comparison is performed under the conditions of ambient temperature 25 ° C. and frequency 10 kHz. The permittivity (Dk) and the dielectric loss tangent (Df) were measured. The results are shown in Table 1.

4-3. Coefficient of linear expansion (CTE)
A test piece having a size of 50 mm × 3 mm was prepared from the insulating base material. Using this test piece, the coefficient of linear expansion (CTE) was measured using a thermomechanical analyzer TMA / SS6000 (manufactured by Seiko Instruments, Inc.). The measurement mode was a tension mode, the measurement load was 60.0 mN, the measurement atmosphere was a nitrogen atmosphere, the temperature rise rate was 5 ° C./min, and the analysis temperature range was 0-120 ° C. The results are shown in Table 1.

1,1A, 1B ... Elastic resin, 3 ... Glass cloth, 5 ... Core insulating base material, 7 ... Internal wiring layer, 15 ... Insulating base material laminate, 20 ... Core base material, 10 ... Prepreg, 10A ... Insulating group Material, 31 ... outer wiring layer, 40 ... laminate with copper foil, 41 ... wiring board, 50 ... chip, 55 ... solder, 100 ... electronic component device.

Claims (6)

With a glass cloth
The elastic resin impregnated in the glass cloth and
Including
The stretchable resin is a curable resin composition containing a rubber component, an epoxy resin, and a curing agent for the epoxy resin.
Prepreg. The prepreg according to claim 1, wherein the curing agent contains an ester-based curing agent having an active ester group. With a glass cloth
The elastic resin impregnated in the glass cloth and
Including
The stretchable resin is a cured product of a curable resin composition containing a rubber component, an epoxy resin, and a curing agent for the epoxy resin.
Insulating base material. The insulating base material according to claim 3, wherein the curing agent contains an ester-based curing agent having an active ester group. A conductor substrate comprising the insulating base material according to claim 3 or 4 and a conductor layer provided on the insulating base material. An insulating base material laminate having two or more insulating base materials and
A wiring layer provided on one side or both sides of the insulating base material laminate,
With
A wiring board in which the insulating base material arranged on the outermost layer of the insulating base material laminate is the insulating base material according to claim 3 or 4.

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