WO2016047682A1

WO2016047682A1 - Resin film and laminated film

Info

Publication number: WO2016047682A1
Application number: PCT/JP2015/076914
Authority: WO
Inventors: 達史林; 貴至西村; 俊章田中; 白波瀬　和孝
Original assignee: 積水化学工業株式会社
Priority date: 2014-09-25
Filing date: 2015-09-24
Publication date: 2016-03-31
Also published as: TW201619282A; JPWO2016047682A1

Abstract

Provided is a resin film which, even when cured in various curing environments, gives a cured film that has a reduced dielectric dissipation factor and that can enhance the adhesion of metal wiring. This resin film includes an epoxy resin and a cyanate ester compound, wherein the ratio of the rate of triazine structure formation to the rate of oxazoline structure formation is 0.15-0.4.

Description

Resin film and laminated film

The present invention relates to a resin film containing an epoxy resin and a cyanate ester compound. Moreover, this invention relates to a laminated film provided with the said resin film.

The cured product of the cyanate ester compound exhibits high heat resistance, low thermal expansion, and low dielectric loss tangent. For this reason, the said cyanate ester compound is used as a hardening | curing agent of an epoxy resin in order to provide said performance to an epoxy resin. A resin composition containing an epoxy resin and a cyanate ester compound is used as a material for a resin film for a printed wiring board including a build-up film.

A resin composition containing an epoxy resin and a cyanate ester compound is disclosed in Patent Document 1 below.

WO2003 / 099952A1

The curing reaction of the epoxy resin by the cyanate ester compound is different from the curing reaction of the epoxy resin by a general phenol resin. It is known that the curing reaction of an epoxy resin with a cyanate ester compound has a very large reaction path and is complicated. Therefore, the properties of the resulting cured product may vary depending on the environment to be cured.

In recent years, build-up films have been used in various processing methods. When a cyanate ester compound is used, stable performance may not be exhibited in terms of dielectric properties and wiring adhesion depending on the curing environment.

As a result of the study by the present inventors, particularly in an environment where the surface of the resin film is sealed, when the resin film is cured, the reaction path changes greatly, and the triazine structure is formed by the self-polymerization of the cyanate ester compound. It was found that many oxazoline structures were easily formed. As a result, the dielectric characteristics are deteriorated or excessive etching occurs in the desmear process, and the adhesion of the wiring is not exhibited. On the other hand, if the formation of the triazine structure is promoted too much, hydrolysis and heat resistance of the cured product tends to be significantly reduced due to hydrolysis of the triazine structure, and wiring adhesion tends to be lowered.

An object of the present invention is to provide a resin film that can lower the dielectric loss tangent and increase the adhesion of metal wiring in the obtained cured product even when cured in various curing environments. Another object of the present invention is to provide a laminated film including the above resin film.

According to a wide aspect of the present invention, a resin film containing an epoxy resin and a cyanate ester compound, a resin film cured at 140 ° C. for 5 minutes, and a resin film cured at 140 ° C. for 10 minutes. And each of the four resin films cured at 140 ° C. for 15 minutes, the surface FT-IR spectrum was measured, and the peak value derived from the triazine structure of each of the four resin films and Obtain the maximum value of the peak derived from the oxazoline structure of each of the four resin films, calculate the slope when linearly approximated by the least square method using the obtained maximum value, and form the calculated slope as the triazine structure The ratio of the triazine structure formation rate to the oxazoline structure formation rate is 0.15 or more. Is 0.4 or less, the resin film is provided.

The resin film preferably contains a compound having an alcoholic hydroxyl group as the epoxy resin or as a compound other than the epoxy resin. The resin film preferably contains a curing accelerator. The resin film is preferably an imidazole compound as the curing accelerator.

According to a wide aspect of the present invention, an epoxy resin, a cyanate ester compound, and an imidazole compound are included, and the epoxy resin or a compound other than the epoxy resin includes a compound having an alcoholic hydroxyl group, The ratio of the number of epoxy groups in the epoxy resin to the number of cyanato groups is from 1 to 3, and the number of epoxy groups in the epoxy resin relative to the number of alcoholic hydroxyl groups in the compound containing the alcoholic hydroxyl group The ratio of the content of the imidazole compound in 100% by weight of the resin film to the content of the cyanate ester compound in 100% by weight of the resin film is 0.03 or more and 0.06. The following resin film is provided. Regarding this resin film, the resin film, a resin film that has been cured at 140 ° C. for 5 minutes, a resin film that has been cured at 140 ° C. for 10 minutes, and a resin film that has been cured at 140 ° C. for 15 minutes For each of the four resin films, the surface FT-IR spectrum was measured, and the maximum value of the peak derived from the triazine structure of each of the four resin films and the maximum value of the peak derived from the oxazoline structure of each of the four resin films And using the obtained maximum value to calculate the slope when linearly approximated by the least squares method, and using the calculated slope as the formation rate of the triazine structure and the formation rate of the oxazoline structure, the oxazoline structure The ratio of the formation rate of the triazine structure to the formation rate of is preferably 0.15 or more and 0.4 or less.

The resin film preferably contains a phenoxy resin as the compound having an alcoholic hydroxyl group. The resin film preferably contains an inorganic filler. The inorganic filler is preferably silica.

In a specific aspect of the resin film according to the present invention, the resin film is a build-up film used for a build-up method.

According to a wide aspect of the present invention, there is provided a laminated film comprising the above-described resin film and a base material or a metal foil, wherein the resin film is laminated on the surface of the base material or the metal foil.

The resin film according to the present invention contains an epoxy resin and a cyanate ester compound, and the ratio (the formation rate of the triazine structure / the formation rate of the oxazoline structure) is 0.15 or more and 0.4 or less. Even when cured in the environment, in the obtained cured product, the dielectric loss tangent can be lowered and the adhesion of the metal wiring can be enhanced.

The resin film according to the present invention includes an epoxy resin, a cyanate ester compound, and an imidazole compound, includes a compound having an alcoholic hydroxyl group as the epoxy resin or a compound other than the epoxy resin, and a ratio (number of epoxy groups). / Number of cyanato groups) is 1 or more and 3 or less, ratio (number of epoxy groups / number of alcoholic hydroxyl groups) is 3 or more and 7 or less, ratio (content of imidazole compound (wt%) / cyanate) Since the content (% by weight) of the ester compound is 0.03 or more and 0.06 or less, even when cured in various curing environments, the resulting cured product has a low dielectric loss tangent and metal wiring. It is possible to improve the adhesion.

Hereinafter, the details of the present invention will be described.

(Resin film)
(Configuration (1)) The resin film according to the present invention preferably contains an epoxy resin and a cyanate ester compound. In the present invention, the ratio of the triazine structure formation rate to the oxazoline structure formation rate (triazine structure formation rate / oxazoline structure formation rate) is preferably 0.15 or more and 0.4 or less.

The above ratio (triazine structure formation rate / triazine structure formation rate and oxazoline structure formation rate) is as follows: resin film (0 minutes at 140 ° C., no cure at 140 ° C.) and 5 minutes at 140 ° C. FT-IR spectrum of each of four resin films: a resin film that has been cured for 10 minutes at 140 ° C., and a resin film that has been cured for 15 minutes at 140 ° C. The maximum value of the peak derived from the triazine structure of each of the four resin films and the maximum value of the peak derived from the oxazoline structure of each of the four resin films were obtained, and by the least square method using the maximum values obtained. The slope at the time of linear approximation is calculated, and the calculated slope is obtained as the formation rate of the triazine structure and the formation rate of the oxazoline structure. In measurement of the above ratio (formation rate of triazine structure / formation rate of oxazoline structure), a resin film cured at 140 ° C. for 5 minutes, a resin film cured at 140 ° C. for 10 minutes, and at 140 ° C. The resin film which has been cured for 15 minutes can be obtained by curing the resin film on which the FT-IR spectrum is measured in a state where it is in contact with the atmosphere.

By adopting the above-described configuration (1) in the resin film according to the present invention, it is possible to lower the dielectric loss tangent and improve the adhesion of the metal wiring in the obtained cured product even when cured in various curing environments. it can. In the present invention, the above effects are effectively exhibited by controlling the generation rate of the triazine structure and the oxazoline structure generated by the reaction between the epoxy resin and the cyanate ester compound within a certain range.

(Configuration (2)) The resin film according to the present invention includes an epoxy resin, a cyanate ester compound, and an imidazole compound, and a compound having an alcoholic hydroxyl group as the epoxy resin or a compound other than the epoxy resin. It is preferable to include. The ratio of the number of epoxy groups in the epoxy resin to the number of cyanato groups in the cyanate ester compound (the number of epoxy groups / the number of cyanato groups) is preferably 1 or more and 3 or less. The ratio of the number of epoxy groups in the epoxy resin to the number of alcoholic hydroxyl groups in the compound containing an alcoholic hydroxyl group (number of epoxy groups / number of alcoholic hydroxyl groups) is preferably 3 or more and 7 or less. Ratio of content of imidazole compound in 100% by weight of resin film to content of cyanate ester compound in 100% by weight of resin film (content of imidazole compound (% by weight) / content of cyanate ester compound (weight) %)) Is preferably 0.03 or more and 0.06 or less.

In the cured film obtained by adopting the above-described configuration (2) in the resin film according to the present invention or being cured in various curing environments, the dielectric loss tangent is lowered and the adhesion of the metal wiring is increased. Can do. In this invention, since the production | generation speed | rate of the triazine structure and oxazoline structure which are produced | generated by reaction with an epoxy resin and a cyanate ester compound can be controlled to a fixed range, said effect is exhibited effectively.

A resin film satisfying the above configuration (1) can be easily obtained by a resin film satisfying the above configuration (2).

Regardless of the curing environment, the resin film that satisfies the above configuration (2) satisfies the above configuration (1) from the viewpoint of effectively lowering the dielectric tangent and effectively improving the adhesion of the metal wiring. It is preferable to do. In the resin film satisfying the configuration (2), it is preferable that the ratio (the formation rate of the triazine structure / the formation rate of the oxazoline structure) is 0.15 or more and 0.4 or less.

In addition, from the viewpoint of effectively lowering the dielectric loss tangent and effectively improving the adhesion of the metal wiring, regardless of the curing environment, in the configuration (1), the resin film has an alcoholic hydroxyl group. Preferably, the resin film contains a curing accelerator, and the resin film is preferably an imidazole compound as the curing accelerator.

In the present invention, for example, even if the surface of the resin film is exposed, covered, or even if the surface of the resin film is in contact with the atmosphere or in contact with a gas having a low oxygen concentration, The tangent can be lowered and the adhesion of the metal wiring can be increased. Even if the surface of the resin film is covered, the surface roughness of the surface is reduced, and the adhesion between the cured product and the metal wiring is increased. Even if the surface of the resin film is covered, the ratio (the formation rate of the triazine structure / the formation rate of the oxazoline structure) is not less than the lower limit as long as the configuration (1) or the configuration (2) is satisfied. If so, the dielectric loss tangent is effectively reduced. Even if the surface of the resin film is covered, the ratio (the formation rate of the triazine structure / the formation rate of the oxazoline structure) is not less than the lower limit as long as the configuration (1) or the configuration (2) is satisfied. If it exists, after moisture absorption arises in the state in which the metal wiring was formed on the hardened | cured material, adhesiveness does not fall easily. In this invention, the adhesiveness of the hardened | cured material and metal wiring after moisture absorption can be improved.

Regardless of the curing environment, from the viewpoint of effectively reducing the dielectric loss tangent and effectively improving the adhesion of the metal wiring, the above ratio (the formation rate of the triazine structure / the formation rate of the oxazoline structure) is preferably 0. .20 or more, preferably 0.35 or less.

Specifically, the surface FT-IR spectrum is measured under the following conditions. The surface FT-IR spectrum is measured in the ATR measurement mode of a Fourier transform infrared spectrophotometer “NICOLET 380” (FT-IR). The resulting ^peaks, after normalization by the maximum peak value between 1490cm ^-1 ~ 1520cm -1 (allyl-derived ^peak), the maximum peak value between 1550cm ^-1 ~ 1580cm -1 (derived from triazine structure Peak) and a maximum peak value between 1660 cm ⁻¹ and 1690 cm ⁻¹ (peak derived from the oxazoline structure).

Regardless of the curing environment, from the viewpoint of effectively lowering the dielectric loss tangent and effectively improving the adhesion of the metal wiring, the epoxy group in the epoxy resin relative to the number of cyanate groups in the cyanate ester compound. The number ratio (number of epoxy groups / number of cyanato groups) is preferably 1 or more, more preferably 1.5 or more, preferably 3 or less, more preferably 2.5 or less. When the ratio (number of epoxy groups / number of cyanato groups) is not less than the above lower limit, the generation rate of the triazine structure does not become too fast, the decrease in wet heat resistance of the resulting cured product is suppressed, and the wiring adhesion is There is a tendency to improve. If the ratio (number of epoxy groups / number of cyanato groups) is less than or equal to the above upper limit, the generation rate of the oxazoline structure does not become too fast, the deterioration of dielectric properties is prevented, and excessive etching occurs in the desmear process. It becomes difficult to improve the adhesion of the wiring.

Regardless of the curing environment, from the viewpoint of effectively lowering the dielectric loss tangent and effectively improving the adhesion of the metal wiring, the epoxy resin in the epoxy resin relative to the number of alcoholic hydroxyl groups in the compound containing the alcoholic hydroxyl group. The ratio of the number of epoxy groups (number of epoxy groups / number of alcoholic hydroxyl groups) is preferably 3 or more, more preferably 5 or more, and preferably 7 or less.

Regardless of the curing environment, the resin film relative to the content of the cyanate ester compound in 100% by weight of the resin film from the viewpoint of effectively reducing the dielectric loss tangent and effectively improving the adhesion of the metal wiring. The ratio of the content of the imidazole compound in 100% by weight (content of imidazole compound (% by weight) / content of cyanate ester compound (% by weight)) is preferably 0.03 or more, more preferably 0.035 or more. , Preferably 0.06 or less, more preferably 0.055 or less. Further, when the ratio (content of imidazole compound (% by weight) / cyanate ester compound (% by weight)) is not less than the above lower limit and not more than the above upper limit, the rate of formation of the triazine structure relative to the rate of formation of the oxazoline structure It becomes easy to keep the ratio within the preferred range described above. As a result, the dielectric characteristics are improved and the adhesion of the wiring is increased.

Hereinafter, details of each component used for the resin film according to the present invention will be described.

[Epoxy resin]
The epoxy resin (epoxy compound) contained in the resin film is not particularly limited. A conventionally well-known epoxy resin can be used as this epoxy resin. The epoxy resin refers to an organic compound having at least one epoxy group. As for an epoxy resin, only 1 type may be used and 2 or more types may be used together.

Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, biphenol type epoxy resin, and naphthalene type epoxy resin. Fluorene type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, epoxy resin having adamantane skeleton, epoxy resin having tricyclodecane skeleton, and triazine nucleus Examples thereof include an epoxy resin having a skeleton. The epoxy resin may not have a triazine structure.

The epoxy resin preferably has a biphenyl skeleton, and is preferably a biphenyl type epoxy resin. When the epoxy resin has a biphenyl skeleton, the adhesion between the cured product and the metal wiring is further enhanced.

From the viewpoint of further reducing the surface roughness of the cured product and further improving the adhesion between the cured product and the metal wiring, the epoxy equivalent of the epoxy resin is preferably 90 or more, more preferably 100 or more. , Preferably 1000 or less, more preferably 800 or less.

From the viewpoint of obtaining a resin film that is more excellent in storage stability, the molecular weight of the epoxy resin is preferably 200 or more, more preferably 350 or more, preferably 3000 or less, more preferably 1000 or less.

The molecular weight of the epoxy resin is more preferably 1000 or less. In this case, even if the content of the inorganic filler in the resin film is 50% by weight or more, a resin film that flows appropriately can be obtained. When the resin film is laminated on the substrate, the inorganic filler can be uniformly present.

The resin film may contain a compound having an alcoholic hydroxyl group (an epoxy resin having an alcoholic hydroxyl group) as the epoxy resin. The resin film may contain a compound having an alcoholic hydroxyl group that is an epoxy resin and a compound having an alcoholic hydroxyl group that is not an epoxy resin. Examples of the epoxy resin having an alcoholic hydroxyl group include epoxy resins (multimers of bisphenol type epoxy compounds) obtained by reacting two or more monomers of a bisphenol type epoxy compound. Since the epoxy resin having an alcoholic hydroxyl group inhibits the formation of the triazine structure by the self-polymerization of the cyanate ester compound, it is easy to keep the ratio of the formation rate of the triazine structure to the formation rate of the oxazoline structure below the above-mentioned preferable upper limit. To do. For this reason, an epoxy resin having an alcoholic hydroxyl group is preferably used.

Examples of commercially available epoxy resins having an alcoholic hydroxyl group include “1004” and “1007” manufactured by Mitsubishi Chemical Corporation.

The molecular weight of the epoxy resin and the molecular weight of the cyanate ester compound described below can be obtained from the structural formula when the epoxy resin or cyanate ester compound is not a polymer and when the structural formula of the epoxy resin or cyanate ester compound can be specified. It means the molecular weight that can be calculated. Moreover, when the said epoxy resin or cyanate ester compound is a polymer, a weight average molecular weight is meant.

[Cyanate ester compounds]
The resin film contains a curing agent in order to cure the epoxy resin.

As the curing agent, cyanate ester compound (cyanate ester curing agent), phenol compound (phenol curing agent), amine compound (amine curing agent), thiol compound (thiol curing agent), imidazole compound, phosphine compound, acid anhydride, Examples include active ester compounds and dicyandiamide.

In the present invention, a cyanate ester compound is used as the curing agent. When a cyanate ester compound is used as the curing agent, a cured product in which the dimensional change due to heat is further smaller than when other curing agents are used is obtained. Further, when a cyanate ester compound is used as the curing agent, the surface roughness of the surface of the cured product is further reduced as compared with the case of using another curing agent, and the adhesion between the cured product and the metal wiring is improved. The wiring becomes higher and finer wiring is formed on the surface of the cured product. Moreover, by using the cyanate ester compound, the handling property of the resin film containing a large amount of the inorganic filler is improved, and the glass transition temperature of the cured product is further increased.

The cyanate ester compound is not particularly limited. A conventionally known cyanate ester compound can be used as the cyanate ester compound. As for the said cyanate ester compound, only 1 type may be used and 2 or more types may be used together.

Examples of the cyanate ester compound include novolak-type cyanate ester compounds, bisphenol-type cyanate ester compounds, and prepolymers in which these are partially trimerized. As said novolak-type cyanate ester compound, a phenol novolak-type cyanate ester compound, an alkylphenol-type cyanate ester compound, etc. are mentioned. Examples of the bisphenol type cyanate ester compound include bisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, and tetramethylbisphenol F type cyanate ester compounds.

Commercially available products of the above cyanate ester compounds include phenol novolac-type cyanate ester compounds (“Lonza Japan” “PT-30” and “PT-60”) and prepolymers (Lonza Japan) in which bisphenol-type cyanate ester compounds are trimerized. "BA-230S", "BA-3000S", "BTP-1000S" and "BTP-6020S") manufactured by the company.

The molecular weight of the cyanate ester compound is preferably 3000 or less. In this case, the content of the inorganic filler in the resin film can be increased, and even if the content of the inorganic filler is large, a resin film that flows appropriately can be obtained.

The molecular weight of the cyanate ester compound is preferably 1000 or less. In this case, even if the content of the inorganic filler in the resin film is 50% by weight or more, a resin film that flows appropriately can be obtained.

The surface roughness of the cured product is further reduced, the adhesiveness between the cured product and the metal wiring is further increased, finer wiring is formed on the surface of the cured product, and the cyanate ester compound is excellent. From the viewpoint of imparting insulation reliability, the cyanate ester group equivalent of the cyanate ester compound is preferably 250 or less.

The content of the cyanate ester compound with respect to 100 parts by weight of the epoxy resin is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, preferably 100 parts by weight or less, more preferably 60 parts by weight or less. . When the content of the cyanate ester compound is not less than the above lower limit and not more than the above upper limit, a resin film more excellent in storage stability can be obtained.

[Phenoxy resin]
The resin film does not contain or contains a phenoxy resin. By using the phenoxy resin, which preferably contains a phenoxy resin, the resin film can suppress deterioration in embedding property of the resin film with respect to holes or irregularities in the circuit board and unevenness of the inorganic filler. In addition, since the melt viscosity can be adjusted by using a phenoxy resin, the dispersibility of the inorganic filler is improved, and the resin film is difficult to wet and spread in an unintended region during the curing process. The phenoxy resin is not particularly limited. A conventionally known phenoxy resin can be used as the phenoxy resin. As for the said phenoxy resin, only 1 type may be used and 2 or more types may be used together.

Since the phenoxy resin contains an alcoholic hydroxyl group, the use of the phenoxy resin makes it easy to keep the ratio of the formation rate of the triazine structure to the formation rate of the oxazoline structure below the above-described preferable upper limit. For this reason, the said phenoxy resin is used suitably.

Examples of the phenoxy resin include phenoxy resins having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolak skeleton, a naphthalene skeleton, and an imide skeleton.

Examples of commercially available phenoxy resins include “YP50”, “YP55” and “YP70” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and “1256B40”, “4250”, “4256H40” manufactured by Mitsubishi Chemical Corporation, “ 4275 "," YX6954BH30 "," YX8100BH30 ", and the like.

From the viewpoint of obtaining a resin film having better storage stability, the weight average molecular weight of the phenoxy resin is preferably 5000 or more, more preferably 10,000 or more, preferably 100,000 or less, more preferably 50000 or less.

The weight average molecular weight of the phenoxy resin indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

The content of the phenoxy resin is not particularly limited. In 100% by weight of the resin film, the content of the phenoxy resin is preferably 2% by weight or more, more preferably 4% by weight or more, preferably 15% by weight or less, more preferably 10% by weight or less. When the content of the phenoxy resin is not less than the above lower limit and not more than the above upper limit, the embedding property of the resin film with respect to the holes or irregularities of the circuit board becomes good. When the content of the phenoxy resin is not less than the above lower limit, the resin composition can be more easily formed into a film, and a better insulating layer can be obtained. When the content of the phenoxy resin is not more than the above upper limit, the thermal expansion coefficient of the cured product is further reduced. The surface roughness of the surface of the cured product is further reduced, and the adhesion between the cured product and the metal wiring is further enhanced.

[Inorganic filler]
The resin film does not contain or contains an inorganic filler. The resin film preferably contains an inorganic filler. Use of the inorganic filler further reduces the dimensional change due to heat of the cured product. Furthermore, the surface roughness of the surface of the cured product is further reduced, and the adhesion between the cured product and the metal wiring is further enhanced.

Examples of the inorganic filler include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

The surface roughness of the cured product is reduced, the adhesion between the cured product and the metal wiring is further increased, finer wiring is formed on the surface of the cured product, and better insulation reliability is achieved by the cured product. From the viewpoint of imparting the above, the inorganic filler is preferably silica or alumina, more preferably silica, and still more preferably fused silica. By using silica, the coefficient of thermal expansion of the cured product is further reduced, the surface roughness of the surface of the cured product is effectively reduced, and the adhesion between the cured product and the metal wiring is effectively increased. The shape of silica is preferably substantially spherical.

The average particle size of the inorganic filler is preferably 10 nm or more, more preferably 50 nm or more, further preferably 150 nm or more, preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, and particularly preferably 1 μm or less. is there. When the average particle size of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the size of the holes formed by the roughening treatment or the like becomes fine, and the number of holes increases. As a result, the adhesion between the cured product and the metal wiring is further enhanced.

The median diameter (d50) value of 50% is adopted as the average particle diameter of the inorganic filler. The average particle size can be measured using a laser diffraction / scattering particle size distribution measuring apparatus.

The inorganic filler is preferably spherical and more preferably spherical silica. In this case, the surface roughness of the surface of the cured product is effectively reduced, and the adhesion between the cured product and the metal wiring is effectively increased. When each of the inorganic fillers is spherical, the aspect ratio of each of the inorganic fillers is preferably 2 or less, more preferably 1.5 or less.

The inorganic filler is preferably surface-treated, and more preferably surface-treated with a silane coupling agent. Thereby, the surface roughness of the surface of the roughened cured product is further reduced, the adhesion between the cured product and the metal wiring is further increased, and finer wiring is formed on the surface of the cured product, and more Better inter-wiring insulation reliability and interlayer insulation reliability can be imparted to the cured product.

Examples of the coupling agent include silane coupling agents, titanate coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include methacryl silane, acrylic silane, amino silane, imidazole silane, vinyl silane, and epoxy silane.

In 100% by weight of the resin film, the content of the inorganic filler is preferably 25% by weight or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, particularly preferably 50% by weight or more, preferably 99%. % By weight or less, more preferably 85% by weight or less, still more preferably 80% by weight or less, and particularly preferably 75% by weight or less. When the total content of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the surface roughness of the surface of the cured product is further reduced, and the adhesion between the cured product and the metal wiring is further enhanced. In addition, finer wiring is formed on the surface of the cured product, and at the same time, with this amount of inorganic filler, it is possible to lower the thermal expansion coefficient of the cured product as well as metal copper.

[Curing accelerator]
The resin film does not contain or contains a curing accelerator. The resin film preferably contains a curing accelerator. By using the curing accelerator, the curing rate is further increased. By rapidly curing the resin film, the crosslinked structure in the cured product becomes uniform, the number of unreacted functional groups decreases, and as a result, the crosslinking density increases. The said hardening accelerator is not specifically limited, A conventionally well-known hardening accelerator can be used. As for the said hardening accelerator, only 1 type may be used and 2 or more types may be used together.

Examples of the curing accelerator include imidazole compounds, phenol compounds, compounds having secondary hydroxyl groups, phosphorus compounds, amine compounds, and organometallic compounds.

Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-un Decylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2 ' -Mechi Imidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-Ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-dihydroxymethylimidazole, etc. Can be mentioned.

Examples of the phenol compound include novolak type phenol, biphenol type phenol, naphthalene type phenol, dicyclopentadiene type phenol, aralkyl type phenol, and dicyclopentadiene type phenol.

Examples of commercially available phenol compounds include novolak-type phenols (“TD-2091” manufactured by DIC), biphenyl novolac-type phenols (“MEH-7851” manufactured by Meiwa Kasei Co., Ltd.), and aralkyl-type phenol compounds (“MEH manufactured by Meiwa Kasei Co., Ltd.). -7800 "), and phenols having an aminotriazine skeleton (" LA1356 "and" LA3018-50P "manufactured by DIC).

Moreover, the phenolic compound contains a phenolic hydroxyl group. The phenolic hydroxyl group is not an alcoholic hydroxyl group. Since the phenolic hydroxyl group contained in the phenol compound promotes the formation of the triazine structure, the ratio of the formation rate of the triazine structure to the formation rate of the oxazoline structure is kept above the preferable lower limit by using the phenol compound. It becomes easy. For this reason, the said phenol compound is used suitably. The resin film preferably contains the phenol compound as the curing accelerator.

The content of the phenoxy resin is 10 parts by weight or less with respect to 100 parts by weight of the cyanate ester compound. If the content of the phenoxy resin is not more than the above upper limit, it is possible to control the reaction rate ratio while maintaining good storage stability.

Examples of the compound having a secondary hydroxyl group include an epoxy resin obtained by reacting two or more monomers of a bisphenol type epoxy resin, a phenoxy resin, and the like.

Examples of the phosphorus compound include triphenylphosphine.

Examples of the amine compound include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine and 4,4-dimethylaminopyridine.

Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III). Since the organometallic compound adversely affects the insulation reliability, it may not be substantially contained.

The content of the curing accelerator is not particularly limited. In 100% by weight of the resin film, the content of the curing accelerator and the content of the imidazole compound are each preferably 0.01% by weight or more, more preferably 0.9% by weight or more, preferably 3.0% by weight. Below, more preferably 1.8% by weight or less. A resin film cure | hardens efficiently that content of the said hardening accelerator and the said imidazole compound is more than the said minimum and below the said upper limit. If content of the said hardening accelerator and the said imidazole compound is a more preferable range, the storage stability of a resin composition will become still higher and a much better hardened | cured material will be obtained.

[solvent]
The resin film does not contain or contains a solvent. The solvent may be used to obtain a slurry containing the inorganic filler. As for the said solvent, only 1 type may be used and 2 or more types may be used together.

Examples of the solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, Examples thereof include N, N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone and naphtha which is a mixture.

Most of the above solvent is preferably removed when the resin composition is formed into a film. Therefore, the boiling point of the solvent is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. The content of the solvent in the resin composition is not particularly limited. The content of the solvent can be appropriately changed in consideration of the coating property of the resin composition.

[Other ingredients]
For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, etc., the resin composition includes a leveling agent, a flame retardant, a coupling agent, a colorant, an antioxidant, an ultraviolet degradation inhibitor, An antifoaming agent, a thickener, a thixotropic agent, a thermosetting resin other than the above-described epoxy resin, a thermoplastic resin other than the phenoxy resin, and the like may be added.

Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include vinyl silane, amino silane, imidazole silane, and epoxy silane.

Examples of the other thermosetting resins include polyphenylene ether resins, divinyl benzyl ether resins, polyarylate resins, diallyl phthalate resins, polyimide resins, benzoxazine resins, benzoxazole resins, bismaleimide resins, and acrylate resins.

Examples of the other thermoplastic resins include polyvinyl acetal resins, rubber components, and organic fillers.

(Resin film and laminated film)
The resin film can be obtained by molding the resin composition into a film.

From the viewpoint of more uniformly controlling the degree of cure of the resin film, the thickness of the resin film is preferably 5 μm or more, and preferably 200 μm or less.

As a method for forming the resin composition into a film, for example, an extrusion molding method is used in which the resin composition is melt-kneaded using an extruder, extruded, and then formed into a film using a T-die or a circular die. And a casting molding method in which a resin composition containing a solvent is cast to form a film, and other conventionally known film molding methods. Especially, since it can respond to thickness reduction, the extrusion molding method or the casting molding method is preferable. The film includes a sheet.

A resin film that is a B-stage film can be obtained by forming the resin composition into a film and drying it by heating, for example, at 90 to 200 ° C. for 1 to 180 minutes so that curing by heat does not proceed excessively. .

The film-like resin composition that can be obtained by the drying process as described above is referred to as a B-stage film. The B-stage film is a semi-cured product in a semi-cured state. The semi-cured product is not completely cured and curing can proceed further.

The resin film may not be a prepreg. When the resin film is not a prepreg, migration does not occur along a glass cloth or the like. Further, when laminating or precuring the resin film, the surface is not uneven due to the glass cloth. Moreover, by setting it as the resin film which does not contain a prepreg, the dimensional change by the heat | fever of hardened | cured material becomes small and shape retainability becomes high.

The resin film can be suitably used for forming a laminated film including a base material and a resin film laminated on one surface of the base material.

Examples of the substrate of the laminated film include polyester resin films such as polyethylene terephthalate film and polybutylene terephthalate film, olefin resin films such as polyethylene film and polypropylene film, and polyimide resin film. The surface of the base material may be subjected to a release treatment as necessary.

The resin film can also be suitably used to form a laminated film including a metal foil and a resin film laminated on one surface of the metal foil. Therefore, the resin film includes a resin film and a base material or a metal foil, and is preferably used for forming a laminated film in which the resin film is laminated on the surface of the base material or the metal foil. it can. The metal foil is preferably a copper foil.

The resin film is preferably a build-up film used in the build-up method.

(Roughening treatment and swelling treatment)
The resin film is preferably used to obtain a cured product that is roughened or desmeared. The cured product includes a precured product that can be further cured.

In order to form fine irregularities on the surface of the cured product obtained by pre-curing the resin film, the cured product is preferably roughened. Prior to the roughening treatment, the cured product is preferably subjected to a swelling treatment. The cured product is preferably subjected to a swelling treatment after preliminary curing and before the roughening treatment, and is further cured after the roughening treatment. However, the cured product is not necessarily subjected to the swelling treatment.

As the swelling treatment method, for example, a method of treating a cured product with an aqueous solution or an organic solvent dispersion solution of a compound mainly composed of ethylene glycol or the like is used. The swelling liquid used for the swelling treatment generally contains an alkali as a pH adjuster or the like. The swelling liquid preferably contains sodium hydroxide. Specifically, for example, the swelling treatment is performed by treating the cured product with a 40 wt% ethylene glycol aqueous solution at a treatment temperature of 30 to 85 ° C. for 1 to 30 minutes. The swelling treatment temperature is preferably in the range of 50 to 85 ° C. When the temperature of the swelling treatment is too low, it takes a long time for the swelling treatment, and the adhesion between the cured product and the metal wiring tends to be low.

For the roughening treatment, for example, a chemical oxidant such as a manganese compound, a chromium compound, or a persulfate compound is used. These chemical oxidizers are used as an aqueous solution or an organic solvent dispersion after water or an organic solvent is added. The roughening liquid used for the roughening treatment generally contains an alkali as a pH adjuster or the like. The roughening solution preferably contains sodium hydroxide.

Examples of the manganese compound include potassium permanganate and sodium permanganate. Examples of the chromium compound include potassium dichromate and anhydrous potassium chromate. Examples of the persulfate compound include sodium persulfate, potassium persulfate, and ammonium persulfate.

The method for the roughening treatment is not particularly limited. As the roughening treatment method, for example, 30 to 90 g / L permanganic acid or permanganate solution and 30 to 90 g / L sodium hydroxide solution are used, and the treatment temperature is 30 to 85 ° C. and 1 to 30 minutes. A method of treating a cured product under conditions is preferable. The temperature of the roughening treatment is preferably in the range of 50 to 85 ° C. The number of times of the roughening treatment is preferably once or twice.

The arithmetic average roughness Ra of the surface of the cured product is preferably 50 nm or more, preferably 350 nm or less, more preferably less than 200 nm, still more preferably less than 100 nm. In this case, the adhesiveness between the cured product and the metal wiring is increased, and further finer wiring is formed on the surface of the insulating layer.

(Desmear treatment)
A through-hole may be formed in the hardened | cured material obtained by precuring the said resin film. In the multilayer substrate or the like, a via or a through hole is formed as a through hole. For example, the via can be formed by irradiation with a laser such as a CO ₂ laser. The diameter of the via is not particularly limited, but is about 60 to 80 μm. Due to the formation of the through hole, a smear, which is a resin residue derived from the resin component contained in the cured product, is often formed at the bottom of the via.

In order to remove the smear, the surface of the cured product is preferably desmeared. The desmear process may also serve as a roughening process.

In the desmear treatment, for example, a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfate compound is used in the same manner as the roughening treatment. These chemical oxidizers are used as an aqueous solution or an organic solvent dispersion after water or an organic solvent is added. The desmear treatment liquid used for the desmear treatment generally contains an alkali. The desmear treatment liquid preferably contains sodium hydroxide.

The above desmear treatment method is not particularly limited. As the desmear treatment method, for example, using a 30 to 90 g / L permanganate or permanganate solution and a 30 to 90 g / L sodium hydroxide solution, a treatment temperature of 30 to 85 ° C. and a condition of 1 to 30 minutes And the method of processing hardened | cured material once or twice is suitable. The temperature of the desmear treatment is preferably in the range of 50 to 85 ° C.

The surface roughness of the surface of the desmeared cured product is sufficiently reduced by using the resin film.

Hereinafter, the present invention will be specifically described by giving examples and comparative examples. The present invention is not limited to the following examples.

(Example 1)
7 parts by weight of cyanate ester curing agent-containing liquid (“BA-3000S” manufactured by Lonza Japan Co., Ltd.) (5.25 parts by weight in solid content) and bisphenol A type epoxy resin (“850-S” manufactured by DIC) 7 .2 parts by weight, 7.2 parts by weight of a biphenyl type epoxy resin (“NC-3000-H” manufactured by Nippon Kayaku Co., Ltd.), 0.2 parts by weight of an imidazole compound (“2P4MZ” manufactured by Shikoku Kasei Engineering Co., Ltd.) As a liquid containing a compound having an alcoholic hydroxyl group, 10.3 parts by weight (3.09 parts by weight in solid content) of a phenoxy resin-containing liquid (“YX6954BH30” manufactured by Mitsubishi Chemical Corporation) and a phenol compound (“MEH7851− manufactured by Meiwa Kasei Co., Ltd.) H ") 0.5 parts by weight and a surface treated with a silane coupling agent having an N-phenyl-3-aminopropyl group (" KBM-573 "manufactured by Shin-Etsu Chemical Co., Ltd.) 46.3 parts by weight (34.725 parts by weight in solid content) of a slurry containing spherical silica (admatex “SC4050-HOA”) and a silane coupling agent having a 3-glycidoxypropyl group (Shin-Etsu Chemical) 21.3 parts by weight (solid content 14.91 parts by weight) of a slurry containing spherical silica surface-treated with “KBM-403” manufactured by Kogyo Co., Ltd. (“Advertex” SC4050-HND ”) was mixed uniformly. The resin composition varnish was obtained by stirring at room temperature until a simple solution was obtained.

After applying the resin composition varnish obtained on the release treated surface of a non-silicone release treated PET film ("25X" manufactured by Lintec, thickness 25 µm) using an applicator, a gear oven at 100 ° C And dried for 2 minutes to evaporate the solvent. In this manner, a resin film having a thickness of 40 μm and a solvent remaining amount of 1.0 wt% or more and 4.0 wt% or less was obtained on the PET film.

(Examples 2 to 7 and Comparative Examples 1 to 3)
A resin composition varnish and a resin film were produced in the same manner as in Example 1 except that the types and amounts (parts by weight) of the components were changed as shown in Table 1 below.

(1) Evaluation of surface roughness Copper surface roughening agent (“MEC etch bond CZ-8100” manufactured by MEC) on both surfaces of a glass epoxy substrate (“CS-3665” manufactured by Risho Kogyo Co., Ltd.) on which an inner layer circuit was formed by etching The copper surface was roughened by immersion in The obtained laminate of PET film and resin film was set on both sides of the glass epoxy substrate from the resin film side, and a diaphragm type vacuum laminator (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.) was used. Lamination was performed on both sides of the glass epoxy substrate to obtain an uncured laminated sample A. Lamination was performed by reducing the pressure for 20 seconds to a pressure of 13 hPa or less, and then pressing for 20 seconds at 100 ° C. and a pressure of 0.8 MPa.

In the uncured laminated sample A, the PET film was peeled from the resin film, and the resin film was cured under curing conditions of 140 ° C. and 90 minutes to obtain a cured laminated sample.

The cured laminated sample is put in a swelling solution at 60 ° C. (an aqueous solution prepared from “Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd.) and “Sodium hydroxide” manufactured by Wako Pure Chemical Industries, Ltd. Rock at 20 ° C. for 20 minutes. Thereafter, it was washed with pure water.

Put the above laminated sample swollen into 80 ° C sodium permanganate roughening aqueous solution ("Concentrate Compact CP" manufactured by Atotech Japan, "Sodium hydroxide" manufactured by Wako Pure Chemical Industries, Ltd.), and roughening temperature Rocked at 80 ° C. for 20 minutes. Then, after washing | cleaning for 10 minutes with a 40 degreeC washing | cleaning liquid ("Reduction securigant P" by the Atotech Japan company, "Sulfuric acid" by Wako Pure Chemical Industries Ltd.), it wash | cleaned further with the pure water. In this way, a roughened cured product was formed on the glass epoxy substrate on which the inner layer circuit was formed by etching.

The arithmetic average roughness Ra of the surface of the roughened cured product was measured using a non-contact type surface roughness meter (“WYKO” manufactured by Beiko). The arithmetic average roughness Ra was in accordance with JIS B0601-1994.

[Criteria for surface roughness of cured product]
○: Ra is less than 100 nm Δ: Ra is 100 nm or more and less than 200 nm ΔΔ: Ra is 200 nm or more and less than 300 nm ×: Ra is 300 nm or more

(2) Evaluation of adhesive strength (peel strength) A cured product subjected to the roughening treatment obtained in the above (1) evaluation of surface roughness was prepared.

The surface of the roughened cured product was treated with an alkali cleaner (“Cleaner Securigant 902” manufactured by Atotech Japan) for 5 minutes and degreased and washed. After washing, the cured product was treated with a 25 ° C. pre-dip solution (“Pre-Dip Neogant B” manufactured by Atotech Japan) for 2 minutes. Thereafter, the cured product was treated with an activator solution at 40 ° C. (“Activator Neo Gantt 834” manufactured by Atotech Japan) for 5 minutes to attach a palladium catalyst. Next, the cured product was treated with a reducing solution at 30 ° C. (“Reducer Neogant WA” manufactured by Atotech Japan) for 5 minutes.

Next, the cured product is placed in a chemical copper solution (all manufactured by Atotech Japan “Basic Print Gantt MSK-DK”, “Copper Print Gantt MSK”, “Stabilizer Print Gantt MSK”, “Reducer Cu”). Was carried out until the plating thickness reached about 0.5 μm. After the electroless plating, annealing was performed at a temperature of 120 ° C. for 30 minutes in order to remove the remaining hydrogen gas. All the steps up to the electroless plating step were performed with a treatment liquid of 2 L on a beaker scale and while the cured product was swung.

Next, electrolytic plating was performed on the cured product that had been subjected to electroless plating until the plating thickness reached 25 μm. As an electrolytic copper plating, a copper sulfate solution (“copper sulfate pentahydrate” manufactured by Wako Pure Chemical Industries, Ltd., “sulfuric acid” manufactured by Wako Pure Chemical Industries, Ltd., “basic leveler capaside HL” manufactured by Atotech Japan Co., Ltd., “ using the correction agent Cupracid GS "), plating thickness passing a current of 0.6 a / cm ² was carried out electrolytic plating until approximately 25 [mu] m. After the copper plating treatment, the cured product was heated at 190 ° C. for 2 hours to further cure the cured product. Thus, the hardened | cured material with which the copper plating layer was laminated | stacked on the upper surface was obtained.

In the cured product obtained by laminating the obtained copper plating layer, a 10 mm wide cutout was made on the surface of the copper plating layer. Thereafter, the adhesive strength (peel strength) between the cured product and the copper plating layer was measured using a tensile tester (“AG-5000B” manufactured by Shimadzu Corporation) under the condition of a crosshead speed of 5 mm / min.

[Criteria for adhesive strength]
○: 5.9 N / cm or more Δ: 4.9 N / cm or more and less than 5.9 N / cm ΔΔ: 3.9 N / cm or more and less than 4.9 N / cm ×: less than 3.9 N / cm

(3) Evaluation of degree of adhesion reduction due to moisture absorption A cured product in which the copper plating layer obtained in (2) above was laminated was prepared. The cured product was subjected to a moisture absorption treatment at 130 ° C. and a humidity of 85% for 100 hours using a constant temperature and humidity chamber. Using a tensile tester (“AG-5000B” manufactured by Shimadzu Corporation) for the sample after moisture absorption treatment, the adhesive strength (peel strength) between the cured product and the copper foil is measured at a crosshead speed of 5 mm / min. did. From the value of the adhesive strength before and after moisture absorption (peel strength), the degree of adhesion reduction due to moisture absorption (formula: (value of adhesive strength after moisture absorption / value of adhesive strength after moisture absorption) x 100 (%)) was evaluated. .

[Evaluation Criteria for Degree of Adhesion]
○: Adhesion decrease due to moisture absorption is less than 50% Δ: Adhesion decrease due to moisture absorption is 50% or more and less than 60% ×: Adhesion decrease due to moisture absorption is 60% or more

(4) Method for producing a cured product by normal curing, and method for producing a cured product with a changed curing environment Condition 0: Peeling of PET film and curing under normal environment Above (1) Obtained by evaluation of surface roughness Under the curing conditions in the uncured laminated sample A, the PET film was peeled off, and the resin film was cured in the atmosphere at 140 ° C. for 90 minutes, and then the PET film was peeled off to obtain a laminated sample.
Condition 1: Non-silicone-treated PET is cured in a normal environment without being peeled (1) The PET film is peeled from the resin film under the curing conditions in the uncured laminated sample A obtained by the evaluation of the surface roughness. First, the resin film was cured under curing conditions of 140 ° C. and 90 minutes, and then the PET film was peeled off to obtain a laminated sample.

Condition 2: Silicone-treated PET does not peel off and is cured in a normal environment. Instead of the non-silicone-treated PET film used for the resin film, a silicone-treated PET film (“5011” manufactured by Lintec Corporation) Using a thickness of 25 μm, the PET film was not peeled off, the resin film was cured under curing conditions at 140 ° C. and 90 minutes, and then the PET film was peeled off to obtain a laminated sample.

Condition 3: Cured in a normal environment without peeling off the copper foil Instead of the resin film formed on the PET film, a resin film having a resin film formed on the shiny surface of the copper foil was prepared and used. . Without peeling off the copper foil, the resin film was cured under the curing conditions of 140 ° C. and 90 minutes, and then the copper foil was peeled off by etching with an acid to obtain a laminated sample.

Condition 4: PET film was peeled and cured in a nitrogen environment. The PET film was peeled from the resin film, and the resin film was cured under a nitrogen environment at 140 ° C. for 90 minutes to obtain a laminated sample.

(5) Evaluation of dielectric loss tangent Condition 0: PET obtained by dipping in a copper surface roughening agent (“MEC Etch Bond CZ-8100” manufactured by MEC) and roughening the copper surface. A laminate of a film and a resin film is set on one side of the copper foil from the resin film side, and a diaphragm type vacuum laminator (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.) is used on one side of the copper foil. Lamination was performed to obtain an uncured laminated sample. Lamination was performed by reducing the pressure for 20 seconds to a pressure of 13 hPa or less, and then pressing for 20 seconds at 100 ° C. and a pressure of 0.8 MPa. In the uncured laminated sample, the PET film was peeled from the resin film. Next, it was heated at 140 ° C. for 90 minutes, and then further heated at 180 ° C. for 90 minutes to obtain a cured product. Thereafter, the copper foil was peeled off by etching with an acid to obtain a cured product. The obtained cured product was cut into a size of 2 mm in width and 80 mm in length, and 10 sheets were overlapped to obtain a laminate having a thickness of 400 μm. Using the obtained laminate, and using the “cavity resonance perturbation method dielectric constant measuring device CP521” manufactured by Kanto Electronics Application Development Co., Ltd. and the “network analyzer E8362B” manufactured by Agilent Technologies Inc., at room temperature (23 ° C. The dielectric loss tangent was measured at a measurement frequency of 1 GHz. The dielectric loss tangent was determined according to the following criteria.

Condition 1: In place of the non-silicone-treated PET film used for the resin film, a silicone-treated PET film (“5011” manufactured by Lintec Corporation, thickness 25 μm) was used, and the PET film was not peeled off at 140 ° C. The resin film was cured under curing conditions of 90 minutes, and then the PET film was peeled off to obtain a laminated sample.

[Criteria for dielectric loss tangent]
○: Dielectric tangent is less than 0.007 Δ: Dielectric tangent is 0.007 or more and less than 0.008 ΔΔ: Dielectric tangent is 0.008 or more and less than 0.010 ×: Dielectric tangent is 0.010 or more

(6) Evaluation Method of Resin Reaction Rate Ratio (Triazine Structure Formation Rate / Oxazoline Structure Formation Rate) Condition 0: PET film peeled and cured under normal environment Evaluation of reaction rate ratio of resin film containing cyanate ester resin In order to do this, a varnish was prepared by removing only the spherical silica in the resin films of the examples and comparative examples. After applying the resin composition varnish obtained on the release treated surface of a non-silicone release treated PET film ("25X" manufactured by Lintec, thickness 25 µm) using an applicator, a gear oven at 100 ° C And dried for 3 minutes to evaporate the solvent. In this manner, a resin film having a thickness of 40 μm and a solvent remaining amount of 1.0 wt% or more and 4.0 wt% or less was obtained on the PET film. Next, both sides of a glass epoxy substrate (“CS-3665” manufactured by Risho Kogyo Co., Ltd.) on which an inner layer circuit has been formed by etching are immersed in a copper surface roughening agent (“MEC Etch Bond CZ-8100” manufactured by MEC). The surface was roughened. The obtained laminate of PET film and resin film was set on both sides of the glass epoxy substrate from the resin film side, and a diaphragm type vacuum laminator (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.) was used. Lamination was performed on both surfaces of the glass epoxy substrate to obtain an uncured laminated sample B. Lamination was performed by reducing the pressure for 20 seconds to a pressure of 13 hPa or less, and then pressing for 20 seconds at 100 ° C. and a pressure of 0.8 MPa. In the uncured laminated sample B, the PET film was peeled from the resin film. Next, a resin film, a resin film cured for 5 minutes at 140 ° C. in the air, a resin film cured for 10 minutes at 140 ° C. in the air, and cured at 140 ° C. for 15 minutes in the air The FT-IR spectrum of the surface of each of the four resin films and the resin film that has been processed in the ATR measurement mode of the Fourier transform infrared spectrophotometer “NICOLET 380” (FT-IR) manufactured by Thermo ELECTRON The maximum value of the peak derived from the triazine structure of each of the four resin films and the maximum value of the peak derived from the oxazoline structure of each of the four resin films were obtained, and linearity was obtained by the least square method using the obtained maximum values. The slope when approximated was calculated. The calculated slope was defined as the triazine structure formation rate and the oxazoline structure formation rate.

Evaluation of resin reaction rate ratio when the curing environment is changed:
Condition 1: Non-silicone-treated PET is not peeled and cured in a normal environment In the uncured laminated sample B obtained in (6) above, the PET film is not peeled and the laminated sample is subjected to the same curing conditions. Got. The PET film was peeled from the obtained sample, and the same evaluation was performed using FT-IR.

Condition 2: Silicone-treated PET is not peeled off and cured in a normal environment Instead of a PET film, a silicone-treated PET film (“2511” manufactured by Lintec Corporation, thickness 25 μm) is used to peel off the PET film. First, a laminated sample was obtained under the same curing conditions. The PET film was peeled from the obtained sample, and the same evaluation was performed using FT-IR.

Condition 3: Hardening under normal environment without peeling copper foil Instead of the resin film formed on the PET film, a resin film having a resin film formed on the shiny surface of the copper foil was prepared and used. A laminated sample was obtained under the same curing conditions without peeling off the copper foil. After the copper foil was peeled off by etching with acid, the same evaluation was performed using FT-IR.

Condition 4: PET film was peeled and cured in a nitrogen environment. The uncured laminated sample B obtained in (6) above was cured in a nitrogen environment to obtain a laminated sample. The PET film was peeled from the obtained sample, and the same evaluation was performed using FT-IR.

The results are shown in Table 2 below.

Claims

Including an epoxy resin and a cyanate ester compound,
Four resin films: a resin film, a resin film cured for 5 minutes at 140 ° C., a resin film cured for 10 minutes at 140 ° C., and a resin film cured for 15 minutes at 140 ° C. The surface FT-IR spectrum was measured to obtain the maximum value of the peak derived from the triazine structure of each of the four resin films and the maximum value of the peak derived from the oxazoline structure of each of the four resin films. The triazine structure with respect to the formation rate of the oxazoline structure is calculated by calculating the slope of the linear approximation by the least square method using the obtained maximum value and taking the calculated slope as the formation rate of the triazine structure and the formation rate of the oxazoline structure. The resin film whose formation rate ratio is 0.15 or more and 0.4 or less.
The resin film according to claim 1, comprising a compound having an alcoholic hydroxyl group as the epoxy resin or a compound other than the epoxy resin.
The resin film of Claim 1 or 2 containing a hardening accelerator.
The resin film according to claim 3, comprising an imidazole compound as the curing accelerator.
Including an epoxy resin, a cyanate ester compound, and an imidazole compound,
As a compound other than the epoxy resin or the epoxy resin, including a compound having an alcoholic hydroxyl group,
The ratio of the number of epoxy groups in the epoxy resin to the number of cyanate groups in the cyanate ester compound is 1 or more and 3 or less,
The ratio of the number of epoxy groups in the epoxy resin to the number of alcoholic hydroxyl groups in the compound containing the alcoholic hydroxyl group is 3 or more and 7 or less,
The resin film whose ratio of content of the said imidazole compound in 100 weight% of resin films with respect to content of the said cyanate ester compound in 100 weight% of resin films is 0.03 or more and 0.06 or less.
Four resin films: a resin film, a resin film cured for 5 minutes at 140 ° C., a resin film cured for 10 minutes at 140 ° C., and a resin film cured for 15 minutes at 140 ° C. The surface FT-IR spectrum was measured to obtain the maximum value of the peak derived from the triazine structure of each of the four resin films and the maximum value of the peak derived from the oxazoline structure of each of the four resin films. The triazine structure with respect to the formation rate of the oxazoline structure is calculated by calculating the slope of the linear approximation by the least square method using the obtained maximum value and taking the calculated slope as the formation rate of the triazine structure and the formation rate of the oxazoline structure. The resin film according to claim 5, wherein the ratio of the formation rate is 0.15 or more and 0.4 or less.
As a compound other than the epoxy resin or the epoxy resin, including a compound having an alcoholic hydroxyl group,
The resin film according to any one of claims 2 to 6, comprising a phenoxy resin as the compound having an alcoholic hydroxyl group.
The resin film according to any one of claims 1 to 7, comprising an inorganic filler.
The resin film according to claim 8, wherein the inorganic filler is silica.
The resin film according to any one of claims 1 to 9, which is a build-up film used in a build-up method.
A resin film according to any one of claims 1 to 10;
Comprising a substrate or metal foil,
A laminated film in which the resin film is laminated on the surface of the substrate or metal foil.