Laminate, metal-clad laminated sheet, and printed wiring board

Abstract

Disclosed is a laminate that can be improved in terms of low thermal expansion, low relative permittivity, and low dielectric loss tangent while maintaining drillability. A laminate (S1) according to the present disclosure has an insulating layer comprising: a first insulating layer (1) containing a first glass cloth and a cured product of a resin composition; and a second insulating layer (2) containing a second glass cloth and a cured product of a resin composition. The insulating layer comprises two or more of the first insulating layers (1). The first glass cloth contains 80 mass% or more of SiO2 with respect to the total amount of the first glass cloth. The second glass cloth contains 40 mass% to 70 mass% of SiO2 with respect to the total amount of the second glass cloth.

Description

Laminates, metal-clad laminates, and printed circuit boards

[0001] This disclosure generally relates to laminates, metal-clad laminates and printed circuit boards, and more particularly to laminates, metal-clad laminates and printed circuit boards containing glass cloth.

[0002] Patent Document 1 discloses a laminate. This laminate contains two or more composite layers, each containing a fibrous substrate and a cured product of a thermosetting resin composition. The two or more composite layers include one or more composite layers (X) and one or more composite layers (Y). Composite layer (X) is a layer containing a first fibrous substrate composed of first glass fibers, and composite layer (Y) is a layer containing a second fibrous substrate composed of second glass fibers. The second glass fibers have a higher tensile modulus at 25°C than the first glass fibers.

[0003] The laminate described in Patent Document 1 has the effect of having excellent drillability while possessing elastic modulus and low thermal expansion properties.

[0004] Japanese Patent Publication No. 2022-171669

[0005] The purpose of this disclosure is to provide laminates, metal-clad laminates, and printed circuit boards that can improve low thermal expansion, low dielectric constant, and low dielectric loss tangent while maintaining drillability.

[0006] A laminate according to one aspect of the present disclosure has an insulating layer comprising a first insulating layer containing a first glass cloth and a cured resin composition, and a second insulating layer containing a second glass cloth and a cured resin composition. The insulating layer comprises two or more layers of the first insulating layer. The first glass cloth contains SiO2 relative to the total amount of the first glass cloth. ２ It contains 80% by mass or more of the second glass cloth. The second glass cloth contains SiO in proportion to the total amount of the second glass cloth. ２ It contains 40% to 70% by mass of [the substance].

[0007] A metal-clad laminate according to one aspect of the present disclosure comprises the laminate and a metal layer.

[0008] A printed circuit board according to one aspect of the present disclosure comprises the laminate and conductive wiring.

[0009] Fig. 1 is a schematic cross-sectional view showing an example of the laminate according to the present disclosure. Fig. 2 is a schematic cross-sectional view showing another example of the laminate according to the present disclosure. Fig. 3 is a schematic cross-sectional view showing another example of the laminate according to the present disclosure.

[0010] 1. Overview The laminate according to the present embodiment has an insulating layer including: a first insulating layer containing a first glass cloth and a cured product of a resin composition; and a second insulating layer containing a second glass cloth and a cured product of a resin composition. The insulating layer includes two or more first insulating layers. Based on the total amount of the first glass cloth, the first glass cloth contains SiO ２ in an amount of 80% by mass or more. Based on the total amount of the second glass cloth, the second glass cloth contains SiO ２ in an amount of 40% by mass or more and 70% by mass or less.

[0011] In the laminate of the present embodiment, the glass cloth contained in the first insulating layer and the second insulating layer are different. The first glass cloth of the first insulating layer is made of glass containing SiO ２ in an amount of 80% by mass or more based on the total amount of the first glass cloth, while the second glass cloth of the second insulating layer contains SiO ２ in an amount of 40% by mass or more and 70% by mass or less based on the total amount of the second glass cloth.

[0012] SiO ２ A substrate-containing insulating layer containing only the first glass cloth containing 80% by mass or more of [[end]] as a substrate has lower thermal expansion, lower relative dielectric constant and lower dielectric loss tangent than a substrate-containing insulating layer containing only glass cloth containing less than 80% by mass of SiO ２ as a base material. On the other hand, a substrate-containing insulating layer using only the first glass cloth containing 80% by mass or more of SiO ２ as a base material has lower drill processability than a substrate-containing insulating layer containing only glass cloth containing less than 80% by mass of SiO ２ as a base material.

[0013] Accordingly, the laminate of the present embodiment includes a first insulating layer containing a first glass cloth containing 80% by mass or more of SiO ２ and a first insulating layer containing SiO ２by combining with a second insulating layer containing a second glass cloth containing less than 80% by mass of the above, it is possible to improve low thermal expansion properties, low relative dielectric constant and low dielectric loss tangent in the first insulating layer while maintaining drill processability in the second insulating layer.

[0014] 2. Details The laminate of the present embodiment includes three or more substrate-containing insulating layers. More specifically, the laminate of the present embodiment includes two or more first insulating layers and one or more second insulating layers.

[0015] (1) First insulating layer The first insulating layer contains a first glass cloth and a cured product of a resin composition.

[0016] (1-1) First glass cloth The first glass cloth, based on the total amount of the first glass cloth, contains SiO ２ in an amount of 80% by mass or more. The first glass cloth is formed by weaving a plurality of glass fibers as warp yarns and weft yarns, and each of the plurality of glass fibers preferably contains SiO ２ in an amount of 80% by mass or more. When the content of SiO ２ in the first glass cloth is 80% by mass or more relative to the total amount, the thermal expansion property of the first glass cloth can be reduced, and the relative dielectric constant and dielectric loss tangent can be suppressed to a low level. It is more preferable that the content of SiO ２ in the first glass cloth is 90% by mass or more. The first glass cloth can contain SiO ２ in an amount of 100% by mass or less based on the total amount of the first glass cloth.

[0017] The first glass cloth preferably has a smaller coefficient of thermal expansion (CTE), relative dielectric constant and dielectric loss tangent than the second glass cloth. This makes it easy to form the first insulating layer having lower thermal expansion, lower relative dielectric constant and lower dielectric loss tangent than the second insulating layer. The first glass cloth preferably has a relative dielectric constant of 4.0 or less at 10 GHz. This makes it easy to form the first insulating layer having a lower relative dielectric constant than the second insulating layer. More preferably, the first glass cloth has a relative dielectric constant of 3.9 at 10 GHz.

[0018] Further, the first glass cloth preferably has a coefficient of thermal expansion (CTE) of 0.5 ppm / °C or more and 1.5 ppm / °C or less. This facilitates the formation of a first insulating layer with low thermal expansion properties, and can reduce the CTE of the entire laminate.

[0019] (1-2) Cured product of resin composition The cured product of the resin composition is a cured product of a composition containing a resin.

[0020] <Resin> The resin preferably contains a thermosetting resin. The thermosetting resin is not particularly limited, but preferably includes one or more compounds selected from the group consisting of epoxy resins, phenol resins, cyanate resins, melamine resins, imide resins, dicyandiamide, maleimide compounds, polyphenylene ether compounds having carbon-carbon unsaturated double bonds, hydrocarbon compounds having carbon-carbon unsaturated double bonds, and oxazine compounds. This allows the prepreg to be imparted with characteristics corresponding to various compounds. Preferably, the thermosetting resin includes an epoxy resin. Epoxy resins are excellent in mechanical strength, heat resistance, electrical properties, chemical resistance, adhesiveness and the like.

[0021] When the thermosetting resin contains an epoxy resin, the content of the epoxy resin is 50% by mass or more, preferably 56% by mass or more, more preferably 58% by mass or more, based on the total mass of the thermosetting resin. When the content of the epoxy resin is 50% by mass or more, the glass transition temperature (Tg) of the cured product of the resin composition can be increased.

[0022] On the other hand, the content of the epoxy resin is 70% by mass or less, preferably 64% by mass or less, more preferably 62% by mass or less, based on the total mass of the thermosetting resin. When the content of the epoxy resin is 70% by mass or less, the moisture absorption rate of the cured product of the resin composition can be reduced.

[0023] Preferably, the thermosetting resin contains an epoxy resin and further contains a phenol resin. The phenol resin can function as a curing agent for the epoxy resin. Phenol resins are excellent in processability, heat resistance, durability and the like.

[0024] When the thermosetting resin contains epoxy resin and phenolic resin, the phenolic resin content is 30% by mass or more, preferably 36% by mass or more, and more preferably 38% by mass or more, based on the total amount of thermosetting resin. A phenolic resin content of 30% by mass or more can increase the glass transition temperature (Tg) of the cured resin composition.

[0025] On the other hand, the phenolic resin content is 50% by mass or less, preferably 44% by mass or less, and more preferably 42% by mass or less, relative to the total amount of thermosetting resin. By having a phenolic resin content of 50% by mass or less, the moisture absorption rate of the cured resin composition can be reduced.

[0026] The epoxy resin is not particularly limited, but examples include biphenyl-type epoxy resin, naphthalene-type epoxy resin, bisphenol-type epoxy resin, novolac-type epoxy resin, xylylene-type epoxy resin, arylalkylene-type epoxy resin, naphthalene skeleton-modified epoxy resin, triphenylmethane-type epoxy resin, anthracene-type epoxy resin, dicyclopentadiene-type epoxy resin, norbornene-type epoxy resin, fluorene-type epoxy resin, and the like.

[0027] The phenolic resin is not particularly limited, but examples include novolac-type phenolic resin, naphthalene-type phenolic resin, biphenyl aralkyl-type phenolic resin, and dicyclopentadiene-type phenolic resin.

[0028] <Inorganic Filler> The resin composition may contain an inorganic filler in addition to the resin. The inorganic filler is not particularly limited, but preferably it contains one or more compounds selected from the group consisting of molybdenum compounds, silica, aluminum hydroxide, talc, magnesium hydroxide, and boehmite. This allows the prepreg to be given characteristics corresponding to various compounds. In particular, among the compounds listed above, it is preferable that the inorganic filler contains only silica and molybdenum compounds. This further improves the accuracy of hole positioning by drilling.

[0029] The inorganic filler content is 80 parts by mass or more, preferably 90 parts by mass or more, and more preferably 100 parts by mass or more, per 100 parts by mass of thermosetting resin. If the inorganic filler content is less than 80 parts by mass, the thermal expansion coefficient of the laminate of this embodiment may increase. Also, the thickness accuracy of the laminate of this embodiment may decrease.

[0030] On the other hand, the inorganic filler content is 220 parts by mass or less, preferably 210 parts by mass or less, and more preferably 200 parts by mass or less, per 100 parts by mass of thermosetting resin. If the inorganic filler content exceeds 220 parts by mass, moldability may deteriorate.

[0031] When the inorganic filler contains silica, the silica content is 30 parts by mass or more, preferably 35 parts by mass or more, and more preferably 40 parts by mass or more, per 100 parts by mass of the thermosetting resin.

[0032] On the other hand, the silica content is 200 parts by mass or less, preferably 190 parts by mass or less, and more preferably 180 parts by mass or less, per 100 parts by mass of thermosetting resin.

[0033] When the inorganic filler contains a molybdenum compound, the molybdenum compound is preferably a molybdate. A molybdate is a compound containing a molybdenum oxoanion. More preferably, the molybdate is at least one selected from the group consisting of zinc molybdate, calcium molybdate, and magnesium molybdate.

[0034] The molybdenum compound is preferably supported on inorganic particles. That is, it is preferable that the molybdenum compound is attached to all or part of the surface of each inorganic particle. The inorganic particles are not particularly limited, but talc is preferred. The combination of talc inorganic particles and the molybdenum compound can further improve the drillability, flame retardancy, and insulation reliability of the laminate.

[0035] The content of molybdenum compound particles (particles supporting molybdenum compounds) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, based on the total amount of inorganic filler. On the other hand, the content of molybdenum compound particles is 20% by mass or less, preferably 17% by mass or less, and more preferably 15% by mass or less, based on the total amount of inorganic filler.

[0036] <High Molecular Weight Substances> The resin composition may preferably further contain high molecular weight substances. The weight-average molecular weight of the high molecular weight substances is 100,000 or more, preferably 150,000 or more, and more preferably 200,000 or more. On the other hand, the weight-average molecular weight of the high molecular weight substances is preferably 1,000,000 or less, and more preferably 900,000 or less.

[0037] The high molecular weight material is preferably a copolymer, but may also be a homopolymer. The monomers that make up the copolymer and homopolymer are not particularly limited, but examples include acrylic acid esters and methacrylic acid esters.

[0038] By further including high molecular weight materials in the resin composition, the coefficient of thermal expansion can be further reduced. Furthermore, the thickness accuracy of the laminate formed from the prepreg can also be improved.

[0039] Preferably, the high molecular weight material contains an acrylic monomer copolymer. This allows for an even lower coefficient of thermal expansion compared to the case where the high molecular weight material does not contain an acrylic monomer copolymer. Furthermore, it can improve the accuracy of the laminate's thickness.

[0040] When the high molecular weight material contains an acrylic monomer copolymer, the content of the acrylic monomer copolymer is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and even more preferably 9 parts by mass or more, per 100 parts by mass of the thermosetting resin. A content of 5 parts by mass or more of acrylic monomer copolymer can further reduce the coefficient of thermal expansion. Furthermore, the thickness accuracy of the laminate can also be improved.

[0041] On the other hand, the content of the acrylic monomer copolymer is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and even more preferably 30 parts by mass or less, per 100 parts by mass of the thermosetting resin. By having an acrylic monomer copolymer content of 40 parts by mass or less, the accuracy of hole positioning by drilling can be improved. Furthermore, a decrease in the adhesive strength of the cured resin composition to the metal layer can be suppressed.

[0042] <Other> The resin composition may further contain a curing accelerator. Examples of curing accelerators include imidazole compounds. The imidazole compound is not particularly limited, but examples include 2-ethyl-4-methylimidazole.

[0043] The resin composition may further contain a catalyst. The catalyst is not particularly limited, but examples include α,α'-di(t-butylperoxy)diisopropylbenzene.

[0044] The resin composition may further contain a solvent. The solvent is not particularly limited, but examples include methyl ethyl ketone (MEK). By adjusting the amount of solvent, the resin composition can be made into a varnish.

[0045] (2) Second insulating layer The second insulating layer contains the second glass cloth and a cured product of the resin composition.

[0046] (2-1) Second glass cloth The second glass cloth is made up of SiO2 relative to the total amount of the second glass cloth. ２ It contains 40% to 70% by mass of [unspecified substance]. The second glass cloth is formed by weaving multiple glass fibers as warp and weft threads, and each of the multiple glass fibers is SiO [unspecified substance]. ２ It contains 40% to 70% by mass of the second glass cloth. ２ If the content of this substance is between 40% and 70% by mass relative to the total amount, the drillability can be improved.

[0047] The second glass cloth is preferably a glass cloth made from a glass other than the same type as the first glass cloth. This makes it easy to form a second glass cloth with different properties from the first glass cloth.

[0048] For example, the second glass cloth contains SiO2 relative to the total amount of the second glass cloth. ２ Al ２ O ３ Preferably, the mixture contains 10% to 25% by mass of [the substance] and 20% to 30% by mass of CaO.

[0049] As another example, the second glass cloth contains SiO2 relative to the total amount of the second glass cloth. ２ Al ２ O ３ 10% by mass or more and 25% by mass or less, B ２ O ３ It is preferable that it contains 10% by mass or more and 20% by mass or less.

[0050] As another example, the second glass cloth contains SiO2 relative to the total amount of the second glass cloth. ２ and Al ２ O ３ It is preferable that the total content of these is 88% by mass or more and 95% by mass or less.

[0051] The second glass cloth preferably has a relative permittivity of more than 4.0 and 8.0 or less at 10 GHz. This makes it easier to improve drillability without the relative permittivity of the second insulating layer becoming too high. The second glass cloth is more preferably a relative permittivity of more than 4.0 and 7.0 or less at 10 GHz, and even more preferably a relative permittivity of more than 4.0 and 6.0 or less.

[0052] It is preferable that the difference between the elastic modulus of the first glass cloth at 25°C and the elastic modulus of the second glass cloth at 25°C is within 20 GPa. This reduces the difference in deflection between the first and second insulating layers, improving drillability. It is more preferable that the difference between the elastic modulus of the first glass cloth at 25°C and the elastic modulus of the second glass cloth at 25°C is within 15 GPa, and even more preferable that it is within 10 GPa.

[0053] Furthermore, the second glass cloth preferably has a coefficient of thermal expansion (CTE) of 1.6 ppm / °C or more and 6.0 ppm / °C or less. This prevents the thermal expansion of the second insulating layer from becoming too high, thereby reducing the overall CTE of the laminate.

[0054] (2-2) Cured resin composition The cured resin composition is a cured resin of a resin-containing composition. The cured resin composition in the second insulating layer can be formed in the same way as the cured resin composition in the first insulating layer. In this case, the cured resin composition of the first insulating layer and the second insulating layer are the same, but the glass cloth is different between the first glass cloth and the second glass cloth. When the cured resin composition is the same, the composition of the resin composition used is the same.

[0055] The cured product of the resin composition in the second insulating layer can be formed to be different from the cured product of the resin composition in the first insulating layer. In this case, the resin composition of the first insulating layer and the resin composition of the second insulating layer may use the same raw materials, but with different mixing ratios of each raw material. Alternatively, the resin composition of the first insulating layer and the resin composition of the second insulating layer may be made different by using different types of raw materials.

[0056] (3) Laminate In the laminate of this embodiment, the first insulating layer and the second insulating layer can each be formed from a cured prepreg. That is, the first insulating layer can be formed by curing a prepreg containing a first glass cloth and an uncured resin composition by heating, and the second insulating layer can be formed by curing a prepreg containing a second glass cloth and an uncured resin composition by heating. The uncured resin composition in the prepreg is not in a fully cured state (C stage state), but for example, in a semi-cured state (B stage state). The uncured resin composition in the prepreg hardens by heating and reaches the C stage state.

[0057] Since the laminate of this embodiment comprises three or more substrate-containing insulating layers, it can be formed using at least three prepregs. Since the laminate of this embodiment includes two or more first insulating layers and one or more second insulating layers, it is formed using two or more prepregs for forming the first insulating layers and one or more prepregs for forming the second insulating layer.

[0058] The laminate of this embodiment can be formed by stacking multiple prepregs in the thickness direction and integrating them by heating and pressurizing them. A predetermined number of prepregs can be stacked to form the first insulating layer and the prepregs to form the second insulating layer.

[0059] The laminate S1 shown in Figure 1 comprises a first insulating layer 1 containing a first glass cloth in its two outermost layers (one upper layer and one lower layer), and eight second insulating layers 2 containing a second glass cloth between the two outermost layers.

[0060] The laminate S2 shown in Figure 2 comprises a first insulating layer 1 containing a first glass cloth in its outermost four layers (two upper layers and two lower layers), and six second insulating layers 2 containing a second glass cloth between the four outermost layers.

[0061] The laminate S3 shown in Figure 3 comprises a first insulating layer 1 containing a first glass cloth in the two outermost layers (one upper layer and one lower layer), a first insulating layer 1 containing a first glass cloth in the two middle layers of the laminate S3 (the fifth and sixth layers from the top), and three layers of a second insulating layer 2 containing a second glass cloth between each of the outermost layer and the two middle layers.

[0062] In this embodiment, the laminate preferably has a relative permittivity of 4.8 or less at 10 GHz, and more preferably 4.5 or less. This allows for a faster propagation speed of electrical signals.

[0063] The laminate of this embodiment may contain a total of four or more layers of the first insulating layer and the second insulating layer. This allows the laminate to have a thickness greater than or equal to a predetermined thickness, thereby increasing the rigidity of the laminate. Alternatively, the laminate of this embodiment may contain a total of 25 or fewer layers of the first insulating layer and the second insulating layer. This allows the laminate to have a thickness less than or equal to a predetermined thickness, thereby reducing the thickness of the laminate.

[0064] In this embodiment, when the laminate contains a total of four or more layers of the first insulating layer and the second insulating layer, it is preferable that the second insulating layer contains two or more layers. This improves the drillability compared to a laminate containing fewer than two layers of the second insulating layer (a laminate composed only of the first insulating layer or a laminate containing one layer of the second insulating layer).

[0065] In this embodiment, it is preferable that the number of first insulating layers in the laminate is the same as or less than the number of second insulating layers. This results in the number of second insulating layers, which have excellent drillability, being equal to or greater than the number of first insulating layers, thereby improving the drillability of the laminate.

[0066] In the laminate of this embodiment, the first insulating layer is preferably located on the outermost surface of the laminate. This places the first insulating layer, which has a low CTE, on the outermost surface of the laminate, thereby reducing the overall CTE of the laminate. In other words, even if the second insulating layer expands inside the laminate, the first insulating layer can suppress that expansion.

[0067] In the laminate of this embodiment, it is preferable that the first insulating layer is located on the outermost surface of both sides of the laminate. This allows the expansion of the second insulating layer inside the laminate to be suppressed by both first insulating layers, thereby further reducing the CTE of the entire laminate.

[0068] (4) Metal-clad laminate The metal-clad laminate of this embodiment comprises the above-mentioned laminate and a metal layer. If the solid metal layer is provided on only one side of the plate-shaped laminate, it becomes a single-sided metal-clad laminate, and if the solid metal layer is provided on both sides of the plate-shaped laminate, it becomes a double-sided metal-clad laminate. Examples of metals included in the metal layer include copper and aluminum.

[0069] The metal-clad laminate of this embodiment can be formed by layering metal foil together with the prepreg that constitutes the laminate, and then heating and pressing it. The metal foil is bonded to the surface of the laminate by the hardening of the prepreg.

[0070] In this embodiment, the metal-clad laminate has the above-mentioned laminate formed as an insulating layer. Therefore, the metal-clad laminate of this embodiment has low thermal expansion, low dielectric constant, and low dielectric loss tangent. Furthermore, because the metal-clad laminate of this embodiment has a second insulating layer, drillability can be improved.

[0071] The heating temperature used when manufacturing the metal-clad laminate is, for example, between 200 and 250°C. The pressure used when manufacturing the metal-clad laminate is, for example, between 1 MPa and 5 MPa. Furthermore, the heating and pressurizing time used when manufacturing the metal-clad laminate is, for example, between 30 minutes and 120 minutes.

[0072] (5) Printed wiring board The printed wiring board of this embodiment comprises the laminate and conductor wiring described above. The conductor wiring has an appropriate pattern shape. The conductor wiring is, for example, wiring used to transmit signals and wiring used to supply power. The material of the conductor wiring is the same as the material of the metal layer. The conductor wiring may be provided on the surface of the laminate or inside the laminate.

[0073] Printed circuit boards are obtained by applying a subtractive method to the above-mentioned metal-clad laminate. That is, unnecessary portions of the metal layer in the metal-clad laminate are removed by etching to form conductor wiring with a desired pattern shape. Alternatively, printed circuit boards may be obtained by forming conductor wiring on the above-mentioned laminate using an additive method.

[0074] In this embodiment, the laminated structure is formed as an insulating layer. Therefore, the printed circuit board of this embodiment has low thermal expansion, low dielectric constant, and low dielectric loss tangent. Furthermore, because the printed circuit board of this embodiment has a second insulating layer, drillability can be improved, and through-holes and the like can be formed with high precision.

[0075] (6) Modified Examples In the above embodiments, a laminate containing two types of substrate-containing insulating layers, a first insulating layer 1 and a second insulating layer 2, has been described, but the invention is not limited thereto. The present disclosure may further include a laminate containing a substrate-containing insulating layer of a different type from the first insulating layer 1 and the second insulating layer 2. In this case, the laminate may contain one or more different types of substrate-containing insulating layers. The different types of substrate-containing insulating layers include cases where the type of glass cloth is different and the type (composition) of the resin composition is the same as the first insulating layer 1 and the second insulating layer 2, cases where the type of glass cloth is the same and the type of resin composition is different, and cases where the type of glass cloth is different and the type of resin composition is different.

[0076] (7) Aspects As is clear from the above embodiments, this disclosure includes the following aspects. Hereafter, reference numerals are enclosed in parentheses solely to indicate the correspondence with the embodiments.

[0077] The laminate (S1, S2, S3) according to the first embodiment has an insulating layer comprising: a first insulating layer (1) containing a first glass cloth and a cured resin composition; and a second insulating layer (2) containing a second glass cloth and a cured resin composition. The insulating layer comprises two or more layers of the first insulating layer (1). The first glass cloth contains SiO2 relative to the total amount of the first glass cloth. ２ It contains 80% by mass or more of the second glass cloth. The second glass cloth contains SiO in proportion to the total amount of the second glass cloth. ２ It contains 40% to 70% by mass of [the substance].

[0078] According to this embodiment, the laminate (S1, S2, S3) can improve low thermal expansion, low relative permittivity, and low dielectric loss tangent while maintaining drillability.

[0079] The second embodiment is a laminate (S1, S2, S3) based on the first embodiment. In the second embodiment, the first insulating layer (1) and the second insulating layer (2) are provided in a total of 4 to 25 layers.

[0080] The third embodiment is a laminate based on the first or second embodiment. In the third embodiment, the second insulating layer (2) is included in two or more layers.

[0081] The fourth embodiment is a laminate (S1, S2, S3) based on any one of the first to third embodiments. In the fourth embodiment, the number of first insulating layers (1) is the same as or less than the number of second insulating layers (2).

[0082] The fifth embodiment is a laminate (S1, S2, S3) based on any one of the first to fourth embodiments. In the fifth embodiment, the first insulating layer (1) is located on the outermost surface of the laminate (S1, S2, S3).

[0083] The sixth embodiment is a laminate (S1, S2, S3) based on any one of the first to fifth embodiments. In the sixth embodiment, the second glass cloth is composed of SiO2 in relation to the total amount of the second glass cloth. ２ Al ２ O ３ It contains 10% to 25% by mass of [unspecified substance] and 20% to 30% by mass of CaO.

[0084] The seventh embodiment is a laminate (S1, S2, S3) based on any one of the first to fifth embodiments. In the seventh embodiment, the second glass cloth is composed of SiO2 relative to the total amount of the second glass cloth. ２ Al ２ O ３ 10% by mass or more and 25% by mass or less, B ２ O ３ It contains 10% to 20% by mass.

[0085] The eighth aspect is a laminate (S1, S2, S3) based on any one of the first to fifth aspects. In the eighth aspect, the second glass cloth is composed of SiO2 in relation to the total amount of the second glass cloth. ２ and Al ２ O ３ The total content of these substances is between 88% by mass and 95% by mass.

[0086] The ninth embodiment is a laminate (S1, S2, S3) based on any one of the first to eighth embodiments. In the ninth embodiment, the relative permittivity of the first glass cloth at 10 GHz is 4.0 or less. The relative permittivity of the second glass cloth at 10 GHz is greater than 4.0 and 8.0 or less.

[0087] The tenth embodiment is a laminate (S1, S2, S3) based on any one of the first to ninth embodiments. In the tenth embodiment, the relative permittivity of the laminate (S1, S2, S3) at 10 GHz is 4.8 or less.

[0088] The eleventh embodiment is a laminate (S1, S2, S3) based on any one of the first to tenth embodiments. In the eleventh embodiment, the difference between the elastic modulus of the first glass cloth at 25°C and the elastic modulus of the second glass cloth at 25°C is within 20 GPa.

[0089] The twelfth embodiment is a laminate (S1, S2, S3) based on any one of the first to eleventh embodiments. In the twelfth embodiment, the resin composition includes a thermosetting resin and an inorganic filler. The amount of the inorganic filler is 80 parts by mass or more and 220 parts by mass or less per 100 mass of the thermosetting resin.

[0090] The thirteenth embodiment is a laminate (S1, S2, S3) based on the twelfth embodiment. In the thirteenth embodiment, the inorganic filler contains molybdenum compound particles. The content of the molybdenum compound particles is 1% by mass or more and 20% by mass or less of the total amount of the inorganic filler.

[0091] A metal-clad laminate according to the 14th embodiment comprises a laminate (S1, S2, S3) described in any one of the 1 to 13, and a metal layer.

[0092] A printed circuit board according to the 15th embodiment comprises a laminate (S1, S2, S3) described in any one of the 1 to 13, and a conductor wiring.

[0093] The present disclosure will be described in detail below with reference to examples. However, the present disclosure is not limited to the following examples.

[0094] (1) Resin Composition The resin composition was prepared using the components and proportions shown in Table 1. Details of each component used are as follows. - Epoxy resin: Manufactured by DIC Corporation, product name "EPICLON HP7241", triphenylmethane type epoxy resin - Phenolic resin: Manufactured by DIC Corporation, product name "TD-2090", novolac type phenolic resin - Acrylic rubber elastomer: Manufactured by Nagase ChemteX Corporation, product name "PASR", weight-average molecular weight: 500,000 - Imidazole: Shikoku Chemicals, Inc., product name "2E4MZ", 2-ethyl-4-methylimidazole - Silica: Manufactured by Admatex Co., Ltd., product name "SC2050-MTX", silica, D50: 0.5 μm - Molybdenum compound: Manufactured by Huber, product name "KG1100", D50: 2 μm, particles of zinc molybdate supported on talc - First glass cloth #1 (Q glass): SiO ２ : 99% by mass, other components: 1% by mass, cloth style 2118, dielectric constant 3.8 - Second glass cloth #1 (T glass): SiO ２ :66% by mass, Al ２ O ３ : 25% by mass, MgO: 7.3% by mass, Other components: 1.7% by mass, Cloth style 2118, Dielectric constant 5.3 - Second glass cloth #2 (NE glass): SiO ２ :58% by mass, Al ２ O ３ : 16% by mass, B ２ O ３ : 16% by mass, CaO: 5.3% by mass, TiO ２ : 2.5 mass%, MgO: 1.4 mass%, Cloth style 2118, Dielectric constant 4.7 - Second glass cloth #3 (E glass): SiO ２ :55% by mass, Al ２ O ３ : 15% by mass, CaO: 26% by mass, TiO ２: 1% by mass, MgO: 1.7% by mass, other components: 1.3% by mass, cloth style 2118, dielectric constant 6.6 (2) Prepreg The first glass cloth and the second glass cloth were each impregnated with a varnish-state resin composition so that the thickness of the cured prepreg was 100 μm. The resin composition impregnated into the first glass cloth and the second glass cloth was heated and dried at 130°C using a non-contact heating unit until it became a semi-cured product. This removed the solvent from the resin composition and gave a prepreg comprising a glass cloth and a semi-cured product of the resin composition impregnated into the glass cloth. The content of the resin composition in the prepreg was 46% by mass, with the total prepreg being 100% by mass.

[0095] (3) Metal-clad laminate Ten sheets of the prepreg obtained as described above were stacked to obtain a laminate, and copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm, 3EC-VLP-12) was applied as a metal layer to both sides of the obtained laminate to obtain a copper foil-clad laminate. By heating and pressing this copper foil-clad laminate, a metal-clad laminate having metal layers on both sides was obtained. The heating and pressing conditions were 220°C, 2 MPa, and 90 minutes.

[0096] Examples 1 to 3 have the layer configuration of the laminate S1 shown in Figure 1. Specifically, the outermost two layers of the laminate S1 (one upper layer and one lower layer) are provided with a first insulating layer 1 containing a first glass cloth, and between the two outermost layers are eight layers of a second insulating layer 2 containing a second glass cloth.

[0097] Example 4 has the layer configuration of the laminate S2 shown in Figure 2. Specifically, the outermost four layers of the laminate S2 (two upper layers and two lower layers) are provided with a first insulating layer 1 containing a first glass cloth, and six second insulating layers 2 containing a second glass cloth are provided between the four outermost layers.

[0098] The laminates of Comparative Examples 1 to 3 are formed by laminating 10 layers of one type of first insulating layer 1 or second insulating layer 2.

[0099] The same resin composition was used in both the examples and the comparative examples. Furthermore, the same resin composition was used for both the first and second insulating layers.

[0100] (4) Evaluation <CTE50-260> A copper-clad laminate was immersed in an etching solution to remove the copper foil and obtain an insulating substrate (unclad substrate). The insulating substrate was dried at 80°C for 1 hour to remove moisture. This insulating substrate was cut into small pieces measuring 10 mm (Y-axis direction) × 3.5 mm (X-axis direction) × 1.0 mm (Z-axis direction), and the edges were polished. These small pieces were baked at 230°C for 20 minutes to remove residual stress. After that, the small pieces were placed in a desiccator and cooled to room temperature.

[0101] The thermal expansion coefficient (α) was measured using the small pieces obtained as described above. The measurement conditions were as follows:

[0102] • Load: 10 mN • Starting temperature for measurement: Room temperature (but 30°C or lower) • Heating rate: 10°C / min • Measurement mode: Compression method The coefficient of thermal expansion (α) was calculated using the following formula.

[0103]

[0104] L: Length of the small piece at 50°C (Y-axis direction) ΔL: Difference between the length of the small piece at 260°C and the length of the small piece at 50°C ΔT: 210°C (= 260°C - 50°C) <Drillability> Drillability was evaluated by hole position accuracy. For two stacked copper-clad laminates, the amount of hole misalignment on the lower side of the second layer (drill exit side) was measured using a hole position accuracy measuring machine [manufactured by Hitachi Via Mechanics Co., Ltd.], and the average of the hole misalignment at the 10,000th hit + 3σ (σ: standard deviation) was calculated as the hole position accuracy.

[0105] The drilling process was performed by placing a 0.1 mm thick aluminum foil on top of two stacked copper-clad laminates, with a 1.5 mm thick paper phenolic board underneath. The drill diameter was 0.2 mm, and a drilling machine [Hitachi Via Mechanics Co., Ltd., ND-1V212] was used. The drill rotation speed was 160 krpm, the feed rate was 2 m / min, and the chip load was 12.5 μm / rev.

[0106] <Relative permittivity Dk and dielectric loss tangent Df> The relative permittivity Dk and dielectric loss tangent Df at 10 GHz were measured using the cavity resonator perturbation method. A network analyzer (N5230A, manufactured by Keysight Technologies, Inc.) was used as the measurement device.

[0107]

[0108]

[0109] (5) Comparison of Examples and Comparative Examples In terms of drill machinability, Examples 1 to 4 are superior to Comparative Example 1, which was broken.

[0110] In terms of relative permittivity, Examples 1, 2, and 4 are smaller than Comparative Example 2, indicating a low permittivity.

[0111] In terms of relative dielectric loss tangent, Examples 1 to 4 are smaller than Comparative Examples 2 and 3, indicating low dielectric loss tangent.

[0112] In terms of thermal expansion coefficient, Examples 1 to 4 have small values ​​and exhibit low expansion properties.

[0113] Overall, Examples 1 to 4 can improve upon Comparative Examples 1 to 3 in terms of low thermal expansion, low relative permittivity, and low dielectric loss tangent while maintaining drillability.

[0114] S1, S2, S3 Laminate 1 First insulating layer 2 Second insulating layer

Claims

1. The insulating layer comprises a first insulating layer containing a first glass cloth and a cured resin composition, and a second insulating layer containing a second glass cloth and a cured resin composition, wherein the insulating layer comprises two or more layers of the first insulating layer, and the first glass cloth contains SiO2 relative to the total amount of the first glass cloth. ２ It contains 80% by mass or more of the above, and the second glass cloth is made up of SiO in proportion to the total amount of the second glass cloth. ２ A laminate containing 40% to 70% by mass of [the substance].

2. The laminate according to claim 1, comprising a total of 4 to 25 layers of the first insulating layer and the second insulating layer.

3. The laminate according to claim 1, comprising two or more of the second insulating layers.

4. The laminate according to claim 1, wherein the number of first insulating layers is the same as or less than the number of second insulating layers.

5. The laminate according to claim 1, wherein the first insulating layer is located on the outermost surface of the laminate.

6. The second glass cloth contains SiO2 in relation to the total amount of the second glass cloth. ２ Al ２ O ３ The laminate according to claim 1, comprising 10% by mass or more and 25% by mass or less of the above, and 20% by mass or more and 30% by mass or less of CaO.

7. The second glass cloth comprises, based on the total mass of the second glass cloth, SiO ２ in an amount of 55 mass% or more and 60 mass% or less, Al ２ O ３ in an amount of 10 mass% or more and 25 mass% or less, B ２ O ３ in an amount of 10 mass% or more and 20 mass% or less, the laminate according to claim 1.

8. The second glass cloth contains SiO in relation to the total amount of the second glass cloth. ２ and Al ２ O ３ The laminate according to claim 1, wherein the total content of is 88% by mass or more and 95% by mass or less.

9. The laminate according to claim 1, wherein the relative permittivity of the first glass cloth at 10 GHz is 4.0 or less, and the relative permittivity of the second glass cloth at 10 GHz is greater than 4.0 and 8.0 or less.

10. The laminate according to claim 1, wherein the relative permittivity of the laminate at 10 GHz is 4.8 or less.

11. The laminate according to claim 1, wherein the difference between the elastic modulus of the first glass cloth at 25°C and the elastic modulus of the second glass cloth at 25°C is within 20 GPa.

12. The laminate according to claim 1, wherein the resin composition comprises a thermosetting resin and an inorganic filler, and the content of the inorganic filler is 80 parts by mass or more and 220 parts by mass or less per 100 parts by mass of the thermosetting resin.

13. The laminate according to claim 12, wherein the inorganic filler contains molybdenum compound particles, and the content of the molybdenum compound particles is 1% by mass or more and 20% by mass or less with respect to the total amount of the inorganic filler.

14. A metal-clad laminate comprising a laminate according to any one of claims 1 to 13 and a metal layer.

15. A printed circuit board comprising a laminate according to any one of claims 1 to 13 and conductive wiring.

Images