JP2012140570A - Epoxy resin material and multilayer substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin material capable of giving a cured product that is small in the dimensional change by heat and good in embedment properties.SOLUTION: The epoxy resin material includes an epoxy resin, a hardener, an inorganic filler, and a phenoxy resin having an imide skeleton. The content of the phenoxy resin having the imide skeleton is from 1 wt.% or more and 15 wt.% or less on the basis of 100 wt.% of the whole solid content of this epoxy resin material excluding the inorganic filler. This multilayer substrate 11 has a circuit board 12 and a cured product layer 13-16 placed on the surface 12a formed with a circuit of the circuit board 12. This cured product layer 13-16 is formed by curing the epoxy resin material.

Description

  The present invention relates to an epoxy resin material that can be used, for example, to form an insulating layer in a multilayer substrate, and more specifically, an epoxy resin material containing an epoxy resin, a curing agent, an inorganic filler, and a phenoxy resin, and the The present invention relates to a multilayer substrate using an epoxy resin material.

  Conventionally, various resin compositions have been used to obtain electronic components such as laminates and printed wiring boards. For example, in a multilayer printed wiring board, a resin composition is used in order to form an insulating layer for insulating inner layers or to form an insulating layer located in a surface layer portion.

  As an example of the resin composition, Patent Document 1 below discloses a resin composition containing a polyfunctional epoxy resin, a curing agent, at least one of a phenoxy resin and a polyvinyl acetal resin, and an inorganic filler. Has been. Here, the inorganic filler is surface-treated with a silazane compound and then further surface-treated with a silane coupling agent.

  Patent Document 2 below discloses a resin composition containing an epoxy resin, an active ester compound, and an alicyclic structure-containing phenoxy resin. Here, it is described that the resin composition may contain an inorganic filler.

JP 2010-168470 A JP 2010-1111859 A

  The insulating layer of the multilayer printed wiring board is strongly required to hardly peel off from other insulating layers or circuits laminated on the insulating layer. For this reason, in the said insulating layer, it is desired that a dimension does not change a lot with heat. That is, it is desirable that the insulating layer has a low coefficient of linear expansion.

  In recent years, as the density of a package increases, a substrate used in the package is easily warped. For this reason, the request | requirement which makes the curvature of a board | substrate small is increasing very much. In order to sufficiently suppress the warpage of the substrate, it is necessary to reduce the linear expansion coefficient of the insulating layer stacked on the substrate.

  However, when the conventional resin composition as described in Patent Documents 1 and 2 is used, the dimensional change due to heat of the cured product of the resin composition may not be sufficiently reduced. The linear expansion coefficient of the layer may be relatively high.

  An object of the present invention is to provide an epoxy resin material capable of obtaining a cured product having a small dimensional change due to heat and good embedding property, and a multilayer substrate using the epoxy resin material.

  According to a wide aspect of the present invention, the epoxy resin, the curing agent, the inorganic filler, and the phenoxy resin having an imide skeleton, the total solid content excluding the inorganic filler contained in the epoxy resin material is 100% by weight. An epoxy resin material is provided wherein the content of the phenoxy resin having the imide skeleton is 1% by weight or more and 15% by weight or less.

  On the specific situation with the epoxy resin material which concerns on this invention, content of the said inorganic filler is 50 to 85 weight% in 100 weight% of total solid content contained in this epoxy resin material.

  In another specific aspect of the epoxy resin material according to the present invention, the epoxy resin and the curing agent each have a weight average molecular weight of 1000 or less.

  In still another specific aspect of the epoxy resin material according to the present invention, a curing accelerator is further included.

  In another specific aspect of the epoxy resin material according to the present invention, the epoxy resin material is a B-stage film formed into a film shape.

  A multilayer board according to the present invention includes a circuit board and a cured product layer disposed on the surface of the circuit board, and the cured product layer cures the epoxy resin material configured according to the present invention. It is formed by.

  The epoxy resin material according to the present invention includes an epoxy resin, a curing agent, an inorganic filler, and a phenoxy resin having an imide skeleton, and is further included in a total solid content of 100% by weight excluding the inorganic filler contained in the epoxy resin material. Since the content of the phenoxy resin having the imide skeleton is 1% by weight or more and 15% by weight or less, a cured product having a small dimensional change due to heat and good embedding property can be obtained.

FIG. 1 is a partially cutaway front sectional view schematically showing a multilayer substrate using an epoxy resin material according to an embodiment of the present invention.

  Details of the present invention will be described below.

(Epoxy resin material)
The epoxy resin material according to the present invention includes an epoxy resin, a curing agent, an inorganic filler, and a phenoxy resin having an imide skeleton. The said epoxy resin material may contain other phenoxy resins which are not the phenoxy resin which has the said imide skeleton with the phenoxy resin which has the said imide skeleton.

  By adopting the above composition, it becomes possible to obtain a cured product having a small dimensional change due to heat, particularly by using the phenoxy resin having the imide skeleton. When the phenoxy resin having the imide skeleton is used, the phenoxy resin having the imide skeleton is not used, or other phenoxy resins that are not phenoxy resins having the imide skeleton are used. Thus, the dimensional change due to heat of the cured product can be reduced. Addition of phenoxy inherently decreases the crosslink density of the epoxy resin material, resulting in an increase in the coefficient of thermal expansion of the cured product, but the use of a phenoxy resin having an imide skeleton decreases the crosslink density, but the rigid skeleton Therefore, the thermal expansion coefficient of the cured product is lowered, and as a result, the dimensional change due to heat of the cured product can be reduced. Use of the phenoxy resin having the imide skeleton greatly contributes to improvement of the thermal dimensional stability of the cured product.

  Moreover, in an epoxy resin material containing an epoxy resin and a curing agent, by adding a large amount of inorganic filler such as silica, the dimensional change due to heat of the cured product can be further reduced, that is, the linear expansion coefficient is lowered. be able to.

  In a resin composition containing an epoxy resin, a curing agent, and an inorganic filler, if a large amount of solvent is blended, the viscosity of the resin composition becomes low, and appearance defects may easily occur when the resin composition is applied. . Moreover, it is difficult to apply the resin composition to a thickness of 100 μm or more. On the other hand, when the resin composition further contains a phenoxy resin, the viscosity of the resin composition is increased, the film-forming property and coating property of the resin composition are increased, and the resin composition is further applied. Sometimes poor appearance is less likely to occur. Moreover, it becomes easy to apply the resin composition to a thickness of 100 μm or more. In addition, when other phenoxy resin that is not a phenoxy resin having an imide skeleton is used as the phenoxy resin, the crosslink density of the resin composition is lowered by reacting with the curing agent, resulting in a linear expansion coefficient of the cured product. Cause an increase in. On the other hand, the use of a phenoxy resin having an imide skeleton as the phenoxy resin reduces the crosslink density of the resin composition, but the rigid skeleton can suppress an increase in the linear expansion coefficient of the cured product, and the linear expansion A cured product having a low rate can be obtained.

  Moreover, in the B stage film containing an epoxy resin, a curing agent, and an inorganic filler, the melt viscosity of the B stage film is lowered when the weight average molecular weight of one or both of the epoxy resin and the curing agent is 1000 or less. For this reason, when a B-stage film is laminated on a substrate, the inorganic filler tends to exist non-uniformly. Furthermore, if the melt viscosity is low, the B-stage film may spread in an unintended region during the curing process. On the other hand, a B stage film containing an epoxy resin, a curing agent and an inorganic filler, wherein one or both of the epoxy resin and the curing agent has a weight average molecular weight of 1000 or less, is a phenoxy resin. In addition, the melt viscosity of the B-stage film is increased. As a result, the inorganic filler can be uniformly present when the B-stage film is laminated on the substrate. Furthermore, it is possible to suppress the B stage film from spreading unintentionally during the curing process. Here, when the phenoxy resin is a phenoxy resin having an imide skeleton, the crosslink density of the resin composition is lowered, but the rigid skeleton can suppress an increase in the linear expansion coefficient of the cured product, and the linear expansion A cured product having a low rate can be obtained.

  The phenoxy resin plays a role of increasing the melt viscosity of the B stage film and increasing the dispersibility of the inorganic filler in the cured product. Even when the weight average molecular weight of one or both of the epoxy resin and the curing agent is not 1000 or less, the phenoxy resin increases the melt viscosity of the B stage film and increases the dispersibility of the inorganic filler in the cured product. Fulfill.

  When the B stage film containing an epoxy resin, a curing agent, and an inorganic filler does not contain a polymer component such as a phenoxy resin, the B stage film is laminated on the substrate regardless of the melt viscosity. When the film is cured, the appearance of the cured product tends to deteriorate. On the other hand, when the resin composition containing an epoxy resin, a curing agent, and an inorganic filler contains a phenoxy resin, the appearance of the cured product is improved.

  As mentioned above, the use of phenoxy resins has many advantages. In the present invention, among phenoxy resins, by using a phenoxy resin having an imide skeleton, in addition to the above-mentioned many advantages, a cured product having a low coefficient of linear expansion, that is, a small dimensional change due to heat, can be obtained. The present invention has one major feature in this respect.

  The epoxy resin material according to the present invention may be a paste or a film. The epoxy resin material according to the present invention may be a resin composition or a B-stage film molded into the resin composition film.

  Hereinafter, details of each component such as an epoxy resin, a curing agent, an inorganic filler, and a phenoxy resin included in the epoxy resin material according to the present invention will be described.

[Epoxy resin]
The epoxy resin contained in the epoxy resin material 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 novolac type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, and 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 epoxy resin having triazine nucleus in skeleton Etc.

  The epoxy resin preferably contains a bisphenol S type epoxy resin. By using the bisphenol S-type epoxy resin, the dimensional change due to heat of the cured product can be further reduced, and the flatness of the surface of the epoxy resin material embedded in the uneven surface can be further enhanced.

  Moreover, in the resin composition containing the conventional epoxy resin, in order to reduce the dimensional change due to heat of the cured product, that is, in order to reduce the linear expansion coefficient, it is necessary to add a large amount of an inorganic filler such as silica. . In addition, in multilayer boards such as multilayer printed wiring boards, the surface of the cured product is required to be flat, while the surface of the cured product is used to improve the adhesion of the conductive layer and remove smear in the vias. May be roughened or desmeared. When a large amount of inorganic filler is blended in order to lower the linear expansion coefficient of the cured product, the surface roughness of the surface increases when the surface of the cured product of the epoxy resin material is roughened or desmeared.

  On the other hand, the use of bisphenol S type epoxy resin can further reduce the dimensional change due to heat of the cured product, and the surface roughness of the surface of the cured product subjected to the roughening treatment or desmear treatment can be further reduced. Can be small. By using the bisphenol S-type epoxy resin, the linear expansion coefficient of the cured product is sufficiently low even if the content of the inorganic filler is not large.

  Examples of commercially available products of the bisphenol S type epoxy resin include “EXA-1514” and “EXA-1517” manufactured by DIC, “YL7487” and “YL7459” manufactured by Mitsubishi Chemical Corporation.

  From the viewpoint of further reducing the dimensional change due to heat of the cured product and further reducing the surface roughness of the roughened or desmeared cured product, the bisphenol S-type epoxy resin is bifunctional or higher. The bisphenol S type epoxy resin is preferable.

  From the viewpoint of further reducing the surface roughness of the roughened or desmeared cured product, the epoxy equivalent of the epoxy resin is preferably 90 or more, more preferably 100 or more, preferably 1000 or less, more Preferably it is 800 or less.

  The epoxy resin preferably has a weight average molecular weight of 1000 or less. In this case, the content of the inorganic filler in the epoxy resin material can be increased. Furthermore, even if there is much content of an inorganic filler, the resin composition which is an epoxy resin material with high fluidity | liquidity can be obtained. On the other hand, the combined use of an epoxy resin having a weight average molecular weight of 1000 or less and a phenoxy resin can suppress a decrease in melt viscosity of the B stage film that is an epoxy resin material. For this reason, when a B stage film is laminated on a board | substrate, an inorganic filler can be made to exist uniformly.

[Curing agent]
The curing agent contained in the epoxy resin material is not particularly limited. A conventionally known curing agent can be used as the curing agent. As for a hardening | curing agent, only 1 type may be used and 2 or more types may be used together.

  Examples of the curing agent include cyanate ester resin (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. Especially, from a viewpoint of obtaining the hardened | cured material in which the dimensional change by a heat | fever is still smaller, it is preferable that the said hardening | curing agent is cyanate ester resin or a phenol compound. The curing agent is preferably a cyanate ester resin, and is preferably a phenol compound. The curing agent preferably has a functional group capable of reacting with the epoxy group of the epoxy resin.

  From the viewpoint of further reducing the surface roughness of the roughened or desmeared cured product and forming finer wiring on the surface of the cured product, the curing agent may be a cyanate ester resin, a phenol compound, or an activity. An ester compound is preferred. Furthermore, from the viewpoint of imparting good insulation reliability to the cured product, the curing agent is more preferably a cyanate ester resin.

  By using the cyanate resin, the handling property of the B stage film having a large content of the inorganic filler can be improved, and the glass transition temperature of the cured product can be further increased. The cyanate ester resin is not particularly limited. A conventionally known cyanate ester resin can be used as the cyanate ester resin. As for the said cyanate ester resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the cyanate ester resin include novolac type cyanate resin and bisphenol type cyanate resin. Examples of the bisphenol type cyanate resin include bisphenol A type cyanate resin, bisphenol E type cyanate resin, and tetramethylbisphenol F type cyanate resin.

  Commercially available products of the above-mentioned cyanate ester resins include phenol novolak cyanate resins (“PT-30” and “PT-60” manufactured by Lonza Japan), and prepolymers obtained by triazation of bisphenol A dicyanate into trimers. (Lonza Japan "BA230", "BA200" and "BA3000").

  By using the phenol compound, the adhesion between the cured product and the metal layer can be further enhanced. Moreover, by using the said phenol compound, the adhesiveness of hardened | cured material and copper is further improved by carrying out the blackening process or Cz process of the copper surface provided, for example on the surface of the hardened | cured material of a resin composition. be able to.

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

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

  Commercially available products of the above-mentioned 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 the like.

  From the viewpoint of further reducing the surface roughness of the surface of the cured product subjected to the roughening treatment or desmear treatment and forming finer wiring on the surface of the cured product, the phenol compound is a biphenyl novolac type phenol, or An aralkyl type phenol compound is preferred.

  The active ester compound is not particularly limited. As a commercial item of the said active ester compound, "HPC-8000" by DIC, etc. are mentioned.

  From the viewpoint of further reducing the surface roughness of the cured product subjected to the roughening treatment or desmear treatment, forming finer wiring on the surface of the cured product, and imparting good insulation reliability with the curing agent, It is preferable that the said hardening | curing agent contains the hardening | curing agent whose equivalent is 250 or less. For example, when the curing agent is a cyanate ester resin, the equivalent of the curing agent indicates a cyanate ester group equivalent, and when the curing agent is a phenol compound, it indicates a phenolic hydroxyl group equivalent, and the curing agent is an active ester compound. Is the active ester group equivalent.

  The weight average molecular weight of the curing agent is preferably 1000 or less. In this case, the content of the inorganic filler in the epoxy resin material can be increased, and even if the content of the inorganic filler is large, a resin composition that is an epoxy resin material having high fluidity can be obtained. On the other hand, the combined use of a curing agent having a weight average molecular weight of 1000 or less and a phenoxy resin can suppress a decrease in melt viscosity of the B stage film that is an epoxy resin material. For this reason, when a B stage film is laminated on a board | substrate, an inorganic filler can be made to exist uniformly.

  The total content of the epoxy resin and the curing agent in 100% by weight of the total solid content excluding the inorganic filler contained in the epoxy resin material (hereinafter sometimes abbreviated as the total solid content B). Is preferably 75% by weight or more, more preferably 80% by weight or more, preferably 99% by weight or less, more preferably 97% by weight or less.

  When the total content of the epoxy resin and the curing agent is not less than the above lower limit and not more than the above upper limit, an even better cured product can be obtained and the melt viscosity can be adjusted, so that the dispersibility of the inorganic filler And the B stage film can be prevented from spreading in an unintended area during the curing process. Furthermore, the dimensional change due to heat of the cured product can be further suppressed. Further, if the total content of the epoxy resin and the curing agent is less than the lower limit, it becomes difficult to embed the resin composition or B-stage film in the holes or irregularities of the circuit board, and the inorganic filler is not uniform. Tend to exist. When the total content of the epoxy resin and the curing agent exceeds the upper limit, the melt viscosity becomes too low and the B stage film tends to wet and spread in an unintended region during the curing process. “Total solid content B” refers to the total of the epoxy resin, the curing agent, and other solid content blended as necessary. The total solid content B does not contain an inorganic filler. “Solid content” refers to a non-volatile component that does not volatilize during molding or heating.

  The compounding ratio of the epoxy resin and the curing agent is not particularly limited. The compounding ratio of the epoxy resin and the curing agent is appropriately determined depending on the types of the epoxy resin and the curing agent.

[Inorganic filler]
The inorganic filler contained in the epoxy resin material is not particularly limited. Conventional inorganic fillers can be used as the inorganic filler. As for the said inorganic filler, only 1 type may be used and 2 or more types may be used together.

  Examples of the inorganic filler include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride. From the viewpoint of reducing the surface roughness of the cured product subjected to the roughening treatment or desmear treatment, forming finer wiring on the surface of the cured product, and imparting good insulation reliability to the cured product, the above inorganic The filler is preferably silica or alumina, more preferably silica, and still more preferably fused silica. By using silica, the linear expansion coefficient of the cured product can be further lowered, and the surface roughness of the surface of the cured product subjected to the roughening treatment or desmear treatment can be effectively reduced. The shape of silica is preferably substantially spherical.

  The average particle diameter of the inorganic filler is preferably 0.1 μm or more, preferably 20 μm or less, more preferably 1 μm or less. A 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 surface-treated, and more preferably surface-treated with a coupling agent. As a result, the surface roughness of the cured product subjected to the roughening treatment or the desmear treatment can be further reduced, and a finer wiring can be formed on the surface of the cured product, and the cured product has a better wiring. Interlayer insulation reliability and interlayer insulation reliability can be imparted.

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

  The content of the inorganic filler is not particularly limited. The content of the inorganic filler is preferably 50% by weight or more, preferably 85% by weight in 100% by weight of the total solid content (hereinafter sometimes abbreviated as total solid content A) contained in the epoxy resin material. Hereinafter, it is more preferably 80% by weight or less. When the 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 that has been roughened or desmeared can be further reduced, and the surface of the cured product can be further reduced. Fine wiring can be formed, and at the same time, if the amount of the inorganic filler, it is possible to reduce the thermal expansion coefficient of the cured product as well as metal copper. “Total solid content A” refers to the total of the epoxy resin, the curing agent, the inorganic filler, and the solid content blended as necessary. “Solid content” refers to a non-volatile component that does not volatilize during molding or heating.

  When the content of the inorganic filler in the total solid content A is 50% by weight or more, the dimensional change due to heat of the cured product is further reduced, and further, the cured product obtained by using the phenoxy resin having the imide skeleton is used. The effect of improving the thermal dimensional stability is particularly great.

[Phenoxy resin]
The epoxy resin material according to the present invention includes a phenoxy resin. By using the phenoxy resin, the melt viscosity can be adjusted, so that the dispersibility of the inorganic filler can be improved, and the B stage film can be prevented from spreading in an unintended region during the curing process. Moreover, by making the addition amount of the phenoxy resin within a predetermined range, it is possible to make it difficult for the resin composition or the B-stage film to have poor embeddability in the holes or irregularities of the circuit board and to make the inorganic filler non-uniform. .

  Furthermore, the phenoxy resin contained in the epoxy resin material according to the present invention essentially contains a phenoxy resin having an imide skeleton. The phenoxy resin contained in the epoxy resin material according to the present invention may contain another phenoxy resin that is not a phenoxy resin having an imide skeleton.

  Common phenoxy resins may react with curing agents. For this reason, the crosslinking density of the hardened | cured material of an epoxy resin material may fall, and the linear expansion coefficient of hardened | cured material may become high. On the other hand, by using the phenoxy resin having the imide skeleton, it is possible to suppress a decrease in the crosslink density of the cured product of the epoxy resin material, to reduce a dimensional change due to heat of the cured product, and to linearly expand the cured product. The rate can be lowered. By using the phenoxy resin having the imide skeleton, the thermal dimensional stability of the cured product is considerably improved.

  Specific examples of the phenoxy resin having an imide skeleton include “YL7600DMAcH25” manufactured by Mitsubishi Chemical Corporation.

  Examples of the other phenoxy resins include phenoxy resins having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolac skeleton, and a naphthalene skeleton.

  When the surface of the cured product of the resin composition is roughened and then plated to form a metal layer, the adhesive strength between the cured product and the metal layer can be increased, so the other phenoxy resin is It preferably has a biphenyl skeleton, and more preferably has a biphenol skeleton.

  The weight average molecular weight of the phenoxy resin is preferably 5000 or more, and preferably 100,000 or less.

  The content of the phenoxy resin having the imide skeleton is not particularly limited. The content of the phenoxy resin having the imide skeleton is 1% by weight or more and 15% by weight or less in 100% by weight of the total solid content B excluding the inorganic filler contained in the epoxy resin material. The content of the phenoxy resin having the imide skeleton in the total solid content of 100% by weight is preferably 10% by weight or less. When the content of the phenoxy resin having the imide skeleton is not less than the above lower limit and not more than the above upper limit, dimensional change due to heat of the cured product can be further suppressed. Moreover, the embedding property with respect to the hole or the unevenness | corrugation of the circuit board of a resin composition or a B stage film becomes favorable.

  The phenoxy resin may not contain the other phenoxy resin. When the phenoxy resin contains the other phenoxy resin, the content of the other phenoxy resin is preferably 10% in 100% by weight of the total solid content B excluding the inorganic filler contained in the epoxy resin material. % By weight or less, more preferably 5% by weight or less, still more preferably 1% by weight or less.

  The epoxy resin material according to the present invention does not include or includes other phenoxy resins that are not phenoxy resins having the imide skeleton, and when the phenoxy resin includes the other phenoxy resin, the epoxy resin material includes It is particularly preferable that the content of the other phenoxy resin is 1% by weight or less in 100% by weight of the total solid content excluding the inorganic filler.

[Details of other components and epoxy resin materials]
The said epoxy resin material may contain the hardening accelerator as needed. By using a curing accelerator, the curing rate can be further increased. By rapidly curing the epoxy resin material, the crosslinked structure of the cured product can be made uniform, the number of unreacted functional groups can be reduced, and as a result, the crosslinking density can be increased. The curing accelerator is not particularly limited, and a conventionally known curing 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, 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 ′ -Methyl Midazolyl- (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 and 2-phenyl-4-methyl-5-dihydroxymethylimidazole Can be mentioned.

  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).

  From the viewpoint of increasing the insulation reliability of the cured product, the curing accelerator is particularly preferably an imidazole compound.

  The content of the curing accelerator is not particularly limited. From the viewpoint of efficiently curing the epoxy resin material, the content of the curing accelerator in the total solid content B of 100% by weight is preferably 0.01% by weight or more, and preferably 3% by weight or less.

  For the purpose of improving impact resistance, heat resistance, resin compatibility and workability, epoxy resin materials include coupling agents, colorants, antioxidants, UV degradation inhibitors, antifoaming agents, and thickeners. A thixotropic agent and other resins other than those mentioned above 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.

  The content of the coupling agent is not particularly limited. In the total solid content B of 100% by weight, the content of the coupling agent is preferably 0.01% by weight or more and 5% by weight or less.

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

(B-stage film epoxy resin material)
As a method of forming the resin composition into a film, for example, an extrusion molding method in which the resin composition is melt-kneaded using an extruder, extruded, and then formed into a film with a T die or a circular die. Examples thereof include a casting molding method in which the resin composition is dissolved or dispersed in a solvent such as an organic solvent and then cast into a film, and other conventionally known film molding methods. Of these, the extrusion molding method or the casting molding method is preferable because the thickness can be reduced. The film includes a sheet.

  A B-stage film can be obtained by forming the resin composition into a film and drying it by heating at 90 to 200 ° C. for 10 to 180 minutes, for example, 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 said resin composition can be used suitably in order to form a laminated film provided with a base material and the B stage film laminated | stacked on one surface of this base material. A B-stage film of a laminated film is formed from the resin composition.

  Examples of the base material 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, polyimide resin film, metal foil such as copper foil and aluminum foil, and the like. Can be mentioned. The surface of the base material may be subjected to a release treatment as necessary.

  When the epoxy resin material is used as an insulating layer of a circuit, the thickness of the layer formed of the epoxy resin material is preferably equal to or greater than the thickness of the conductor layer that forms the circuit. The thickness of the layer formed of the epoxy resin material is preferably 5 μm or more, and preferably 200 μm or less.

(Printed wiring board)
The said epoxy resin material is used suitably in order to form an insulating layer in a printed wiring board.

  The printed wiring board can be obtained, for example, by heat-pressing the B stage film using a B stage film formed of the resin composition.

  A metal foil can be laminated on one side or both sides of the B-stage film. The method for laminating the B-stage film and the metal foil is not particularly limited, and a known method can be used. For example, the B-stage film can be laminated on the metal foil using an apparatus such as a parallel plate press or a roll laminator while applying pressure while heating or without heating.

(Copper-clad laminate and multilayer board)
The said epoxy resin material is used suitably in order to obtain a copper clad laminated board. An example of the copper-clad laminate is a copper-clad laminate comprising a copper foil and a B stage film laminated on one surface of the copper foil. The copper-clad laminate B-stage film is formed of the epoxy resin material according to the present invention.

  The thickness of the copper foil of the copper-clad laminate is not particularly limited. The thickness of the copper foil is preferably in the range of 1 to 50 μm. Moreover, in order to raise the adhesive strength of the hardened | cured material layer which hardened the epoxy resin material, and copper foil, it is preferable that the said copper foil has a fine unevenness | corrugation on the surface. The method for forming the unevenness is not particularly limited. Examples of the method for forming the unevenness include a formation method by treatment using a known chemical solution.

  Moreover, the epoxy resin material according to the present invention is suitably used for obtaining a multilayer substrate. As an example of the multilayer substrate, there is a circuit substrate including a circuit substrate and a cured product layer laminated on the surface of the circuit substrate. The cured product layer of the multilayer substrate is formed by curing the epoxy resin material. It is preferable that the said hardened | cured material layer is laminated | stacked on the surface in which the circuit of the circuit board was provided. Part of the cured product layer is preferably embedded between the circuits.

  In the multilayer substrate, the surface of the cured product layer opposite to the surface on which the circuit substrate is laminated is preferably roughened or desmeared, and more preferably roughened.

  The roughening method can be any conventionally known roughening method and is not particularly limited. The surface of the cured product layer may be swelled before the roughening treatment.

  Moreover, it is preferable that the said multilayer substrate is further equipped with the copper plating layer laminated | stacked on the surface by which the roughening process of the said hardened | cured material layer was carried out.

  Further, as another example of the multilayer board, a circuit board, a cured product layer laminated on the surface of the circuit board, and a surface of the cured product layer opposite to the surface on which the circuit board is laminated are provided. A circuit board provided with the laminated copper foil is mentioned. The cured product layer and the copper foil are formed by curing the B-stage film using a copper-clad laminate comprising a copper foil and a B-stage film laminated on one surface of the copper foil. Preferably it is. Furthermore, it is preferable that the copper foil is etched and is a copper circuit.

  Another example of the multilayer board is a circuit board including a circuit board and a plurality of cured product layers stacked on the surface of the circuit board. At least one of the plurality of cured product layers is formed by curing the epoxy resin material. It is preferable that the multilayer substrate further includes a circuit laminated on at least one surface of the cured product layer formed by curing the epoxy resin material.

  FIG. 1 is a partially cutaway front sectional view schematically showing a multilayer substrate using an epoxy resin material according to an embodiment of the present invention.

  In the multilayer substrate 11 shown in FIG. 1, a plurality of cured product layers 13 to 16 are laminated on the upper surface 12 a of the circuit substrate 12. The cured product layers 13 to 16 are insulating layers. A metal layer 17 is formed in a partial region of the upper surface 12 a of the circuit board 12. Among the plurality of cured product layers 13 to 16, the cured product layers 13 to 15 other than the cured product layer 16 located on the outer surface opposite to the circuit board 12 side include a metal layer in a partial region of the upper surface. 17 is formed. The metal layer 17 is a circuit. Metal layers 17 are respectively arranged between the circuit board 12 and the cured product layer 13 and between the laminated cured product layers 13 to 16. The lower metal layer 17 and the upper metal layer 17 are connected to each other by at least one of via hole connection and through hole connection (not shown).

  In the multilayer substrate 11, the cured product layers 13 to 16 are formed by curing the epoxy resin material according to the present invention. In this embodiment, since the surfaces of the cured product layers 13 to 16 are roughened or desmeared, fine holes (not shown) are formed on the surfaces of the cured product layers 13 to 16. Further, the metal layer 17 reaches the inside of the fine hole. Moreover, in the multilayer substrate 11, the width direction dimension (L) of the metal layer 17 and the width direction dimension (S) of the part in which the metal layer 17 is not formed can be made small. In the multilayer substrate 11, good insulation reliability is imparted between an upper metal layer and a lower metal layer that are not connected by via-hole connection and through-hole connection (not shown).

(Roughening treatment and swelling treatment)
The epoxy resin material according to the present invention is preferably used in order 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 precured material obtained by precuring the epoxy resin material according to the present invention, the precured material is preferably subjected to a roughening treatment. Prior to the roughening treatment, the precured 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 pre-cured product may not necessarily be subjected to the swelling treatment.

  As a method for the swelling treatment, for example, a method of treating a precured 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 a precured 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 roughened adhesive strength between the cured product and the metal layer tends to be low.

  For the roughening treatment, for example, a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfuric acid 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 a method of the said roughening process, 30-90 g / L permanganic acid or a permanganate solution and 30-90 g / L sodium hydroxide solution are used, for example, process temperature 30-85 degreeC and 1-30 minutes. A method of treating a precured product once or twice under conditions is preferable. It is preferable that the temperature of the said roughening process exists in the range of 50-85 degreeC.

  When the swelling treatment is performed using the swelling liquid and then the roughening treatment is performed using the roughening liquid, the arithmetic average roughness Ra of the surface of the roughened cured product may be 50 nm or more and 350 nm or less. preferable. In this case, the adhesive strength between the cured product and the metal layer or wiring can be increased, and further finer wiring can be formed on the surface of the cured product layer.

(Desmear treatment)
Moreover, a through-hole may be formed in the precured material or hardened | cured material obtained by precuring the epoxy resin material which concerns on this invention. 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 that is a resin residue derived from the resin component contained in the cured product layer is often formed at the bottom of the via.

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

  In the desmear treatment, for example, a chemical oxidant 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 method for the desmear treatment is not particularly limited. As a method for the desmear treatment, 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 A method of treating a precured product or a cured product once or twice is preferable. It is preferable that the temperature of the said desmear process exists in the range of 50-85 degreeC.

  By using the epoxy resin material according to the present invention, the surface roughness of the surface of the cured product subjected to the desmear treatment can be sufficiently reduced.

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

(Epoxy resin)
Bisphenol S type epoxy resin (DIC Corporation "EXA-1517", weight average molecular weight 1000 or less)
Dicyclopentadiene skeleton-containing epoxy resin (“XD-1000” manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight 1000 or less)
Bisphenol F type epoxy resin (“830S” manufactured by DIC, epoxy equivalent 168, weight average molecular weight 500 or less)

(Curing agent)
Aminotriazine skeleton cresol novolac hardener-containing liquid ("LA3018-50P" manufactured by DIC, including a weight average molecular weight of 1000 or less, a solid content of 25% by weight, and a propylene glycol monomethyl ether-containing solvent of 50% by weight)

(Curing accelerator)
Imidazole compound (2-phenyl-4-methylimidazole, “2P4MZ” manufactured by Shikoku Kasei Kogyo Co., Ltd.)

(Phenoxy resin)
Imide skeleton-containing phenoxy resin-containing liquid ("YL7600DMAcH25" manufactured by Mitsubishi Chemical Corporation, containing 25 wt% solids, 37.5 wt% dimethylacetamide, and 37.5 wt% cyclohexanone)
Bisphenol A type phenoxy resin (“YP55” manufactured by Tohto Kasei Co., Ltd.)

(Inorganic filler)
Silica-containing slurry (admatechs “SC2050HNF”, containing fused silica with an average particle size of 0.5 μm, solid content 70 wt% and cyclohexanone 30 wt%)

Example 1
79.1 parts by weight of the above silica-containing slurry (55.4 parts by weight in solids) and 4.9 parts by weight (in solids of 2 LA3018-50P) containing an aminotriazine skeleton cresol novolac curing agent (2 parts by solids) 0.5 parts by weight), 9.0 parts by weight of a bisphenol S type epoxy resin (“EXA-1517” manufactured by DIC) and a dicyclopentadiene skeleton-containing epoxy resin (“XD-1000” manufactured by Nippon Kayaku Co., Ltd.) 8 parts by weight, 0.04 parts by weight of an imidazole compound (“2P4MZ” manufactured by Shikoku Kasei Kogyo Co., Ltd.), and 3.2 parts by weight of the imide skeleton-containing phenoxy resin-containing liquid (“YL7600DMAcH25” manufactured by Mitsubishi Chemical Co., Ltd.) .8 parts by weight) was mixed and stirred at room temperature until a uniform liquid was obtained, to obtain a resin composition varnish.

  A release-treated transparent polyethylene terephthalate (PET) film (“PET5011 550” manufactured by Lintec Corporation, thickness 50 μm) was prepared. The obtained resin composition varnish was applied onto the PET film using an applicator so that the thickness after drying was 50 μm. Next, it was dried in a gear oven at 100 ° C. for 2 minutes to prepare a laminated film of an uncured resin sheet (B stage film) having a length of 200 mm × width of 200 mm × thickness of 50 μm and a polyethylene terephthalate film. Next, the polyethylene terephthalate film was peeled off from the laminated film, and the uncured product of the resin sheet was heated in a gear oven at 180 ° C. for 80 minutes to produce a primary cured product of the resin sheet.

(Examples 2-3 and Comparative Examples 1-3)
A primary cured product of a laminated film and a resin sheet was produced in the same manner as in Example 1 except that the type and amount (parts by weight) of the materials used were changed as shown in Table 1 below. The phenoxy resin used in Comparative Example 2 is a bisphenol A type phenoxy resin (“YP55” manufactured by Tohto Kasei Co., Ltd.). The epoxy resin used in Example 3 is a bisphenol F-type epoxy resin (“830S” manufactured by DIC).

(Evaluation)
(1) Average linear expansion coefficient The primary cured product of the obtained resin sheet was heated at 190 ° C. for 3 hours and further cured to obtain a cured product A. The obtained cured product A was cut into a size of 3 mm × 25 mm. Using a linear expansion coefficient meter (“TMA / SS120C” manufactured by Seiko Instruments Inc.), 0 to 0 of the cured product A cut under the conditions of a tensile load of 3.3 × 10 ⁻² N and a heating rate of 5 ° C./min. The average coefficient of linear expansion at 50 ° C. was measured.

(2) Minimum melt viscosity of epoxy resin material Uncured resin sheet obtained using a Rheometer device ("AR-2000" manufactured by TA Instruments) under the conditions of 21.6% strain and 1 Hz frequency The viscosity of the (B stage film) in the temperature range of 50 to 150 ° C. was measured, and the value at which the viscosity was the lowest was taken as the minimum melt viscosity.

(3) Laminating properties (embedding properties)
A copper-clad laminate (a laminate of a 150 μm thick glass epoxy substrate and a 25 μm thick copper foil) was prepared. The copper foil was etched to produce 26 copper patterns having an L / S of 50 μm / 50 μm and a length of 1 cm to obtain an uneven substrate.

  The uncured product (thickness 50 μm) of the resin sheet obtained in the examples and comparative examples was stacked on the concavo-convex surface of the concavo-convex substrate, and laminate pressure was applied using a vacuum pressurizing laminator machine (model number MVLP-500) manufactured by Meiki Seisakusho. Lamination and pressing were performed at 0.4 MPa and a laminating temperature of 90 ° C. for 20 seconds, and further at a pressing pressure of 0.8 MPa and a pressing temperature of 90 ° C. for 20 seconds. Thus, the laminated body by which the uncured material of the resin sheet was laminated | stacked on the uneven substrate was obtained.

  In the obtained laminate, an uncured product of the resin sheet was heated in a gear oven at 180 ° C. for 80 minutes to obtain a cured product C.

[Lamination evaluation]
The cured product C was cut in a direction orthogonal to the longitudinal direction of each copper pattern to expose the cross section of the cured product C.

  Next, the state of the hardened | cured material C part corresponding to the part (recessed part) in which the copper pattern between each copper pattern is not formed was observed using the optical microscope. Of the 25 portions of the cured product C corresponding to the portion (concave portion) where the copper pattern is not formed, the number T1 of the portions that cannot be embedded is measured, and the adhesion (embedding property) of the cured product C to the uneven surface is evaluated. did.

  Furthermore, each thickness of 26 places of the hardened | cured material C part corresponding to a copper pattern (convex part) was measured using the optical microscope.

  The laminate property was judged according to the following judgment criteria.

[Judgment criteria for laminating properties]
◯: The number T1 of the unembedded portions is 0 and the minimum thickness is 42 μm or more in all the patterns of 26 portions of each pattern. Minimum thickness of 35 μm or more and less than 42 μm ×: The number T1 of the unembedded portions is 1 or more, or the minimum thickness is less than 35 μm in all 26 patterns

  The embedding property and thickness of the cured product C have a correlation with the embedding property and thickness of the epoxy resin material after lamination.

  The results are shown in Table 1 below. In Table 1 below, “total solid content A” indicates the total solid content contained in the epoxy resin material, and “total solid content B” excludes the inorganic filler contained in the epoxy resin material. Total solids are shown.

DESCRIPTION OF SYMBOLS 11 ... Multilayer substrate 12 ... Circuit board 12a ... Upper surface 13-16 ... Hardened | cured material layer 17 ... Metal layer (wiring)

Claims (6)

Including an epoxy resin, a curing agent, an inorganic filler, and a phenoxy resin having an imide skeleton,
The epoxy resin material whose content of the phenoxy resin which has the said imide skeleton is 1 to 15 weight% in 100 weight% of total solid content except the said inorganic filler contained in the epoxy resin material.   The epoxy resin material according to claim 1, wherein the content of the inorganic filler is 50% by weight or more and 85% by weight or less in 100% by weight of the total solid content contained in the epoxy resin material.   The epoxy resin material of Claim 1 or 2 whose weight average molecular weights of the said epoxy resin and the said hardening | curing agent are each 1000 or less.   The epoxy resin material according to any one of claims 1 to 3, further comprising a curing accelerator.   The epoxy resin material according to claim 1, wherein the epoxy resin material is a B-stage film formed into a film shape. A circuit board;
A cured product layer disposed on the surface of the circuit board,
The multilayer substrate in which the said hardened | cured material layer is formed by hardening the epoxy resin material of any one of Claims 1-5.

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