Multilayer body, multilayer body manufacturing method, printed wiring board, semiconductor device, and printed wiring board manufacturing method

Abstract

To provide a multilayer body capable of achieving reduced transmission loss and skew, as well as a multilayer body, a multilayer body manufacturing method, a printed wiring board, a semiconductor device, and a printed wiring board manufacturing method.SOLUTION: A multilayer body 1 includes a first insulating resin layer 2, a metal wiring 4 provided on the surface of the first insulating resin layer 2, and a second insulating resin layer 3 provided on the surface of the first insulating resin layer 2 and covering the metal wiring 4, and the dielectric loss tangent of the second insulating resin layer 3 at a frequency of 10 GHz measured using a perturbation method cavity resonator is lower than the dielectric loss tangent of the first insulating resin layer 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multilayer body, a method for manufacturing a multilayer body, a printed wiring board, a semiconductor device, and a method for manufacturing a printed wiring board. [Background technology]

[0002] In recent years, various electronic devices, such as smartphones, have become lighter, thinner, and smaller, while data communication volume has increased rapidly. In response to this trend, printed wiring boards used in electronic devices are becoming increasingly compatible with high frequencies. An example of a study on such a printed wiring board is Patent Document 1. Patent Document 1 discloses a prepreg, a metal-clad laminate, and a printed wiring board, which include a first resin layer and second resin layers provided on both sides of the first resin layer, wherein the first resin layer is a semi-cured product of a first resin composition that does not contain hexagonal boron nitride and is impregnated into glass cloth, and the second resin layer is a semi-cured product of a second resin composition that contains hexagonal boron nitride, the glass cloth having a warp and weft weave density of 54 threads or more per 25 mm, the hexagonal boron nitride having an average particle size of 10 to 30 μm, and the hexagonal boron nitride is contained in an amount of 20 to 40 parts by mass per 100 parts by mass of the remaining components of the second resin composition excluding the hexagonal boron nitride. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-170748 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned Patent Document 1 states that the relative dielectric constant can be reduced by using the prepreg etc. described in the above-mentioned Patent Document 1. However, no consideration has been given to transmission loss. Meanwhile, reduction of transmission loss and skew is the most desired performance in response to the trend toward lighter, thinner, shorter, and smaller electronic devices and the rapid increase in data communication volume. The present invention is aimed at overcoming this problem, and aims to provide a multilayer body that can achieve transmission loss and skew, as well as a multilayer body, a method for manufacturing a multilayer body, a printed wiring board, a semiconductor device, and a method for manufacturing a printed wiring board. [Means for solving the problem]

[0005] In light of the above-mentioned problems, the present inventors have conducted research and found that the above-mentioned problems can be solved by using a multilayer body in which metal wiring is provided on the surface of an insulating resin layer, and an insulating resin layer having a lower dielectric tangent than the insulating resin layer is further provided so as to cover the metal wiring. Specifically, the above problems were solved by the following means. <1> A multilayer body comprising: a first insulating resin layer; metal wiring provided on a surface of the first insulating resin layer; and a second insulating resin layer provided on the surface of the first insulating resin layer and covering the metal wiring, wherein the dielectric loss tangent of the second insulating resin layer at a frequency of 10 GHz measured with a perturbation method cavity resonator is lower than the dielectric loss tangent of the first insulating resin layer at a frequency of 10 GHz measured with the perturbation method cavity resonator. <2> The thermal expansion coefficient of the first insulating resin layer measured in accordance with the TMA (Thermo-mechanical analysis) method is 30 ppm / °C or less. <1> The multilayer body according to claim 1. <3> a difference between the dielectric loss tangent of the second insulating resin layer and the dielectric loss tangent of the first insulating resin layer being 0.002 or more; <1> or <2> The multilayer body according to claim 1. <4> the thermal expansion coefficient of the first insulating resin layer measured in accordance with a thermo-mechanical analysis (TMA) method is 30 ppm / °C or less; a difference between the dielectric loss tangent of the second insulating resin layer and the dielectric loss tangent of the first insulating resin layer being 0.002 or more; <1> ~ <3> 10. The multilayer body according to any one of the preceding items. <5> The first insulating resin layer includes a fiber base material. <1> ~ <4> 10. The multilayer body according to any one of the preceding items. <6> The first insulating resin layer is a layer formed from a resin composition (1) containing a thermosetting compound and a fiber base material. <1> ~ <5> 10. The multilayer body according to any one of the preceding items. <7> The second insulating resin layer does not contain a fiber base material. <1> ~ <6> 10. The multilayer body according to any one of the preceding items. <8> The second insulating resin layer is a layer formed from a resin composition (2), The resin composition (2) contains a thermosetting compound, and the content of the filler is 0 to 40 mass% of the mass of the resin solid content contained in the resin composition (2). <7> The multilayer body according to claim 1. <9> The second insulating resin layer is disposed so as to be in contact with both surfaces of the first insulating resin layer. <1> ~ <8> 10. The multilayer body according to any one of the preceding items. <10> a metal foil is further disposed so as to be in contact with the surface of the second insulating resin layer opposite to the first insulating resin layer; <9> The multilayer body according to claim 1. <11> the thermal expansion coefficient of the first insulating resin layer measured in accordance with a thermo-mechanical analysis (TMA) method is 30 ppm / °C or less; a difference between the dielectric loss tangent of the second insulating resin layer and the dielectric loss tangent of the first insulating resin layer is 0.002 or more; the first insulating resin layer is a layer formed from a resin composition (1) containing a thermosetting compound and a fiber base material, the second insulating resin layer does not contain a fiber base material, The second insulating resin layer is a layer formed from a resin composition (2), the resin composition (2) contains a thermosetting compound, and the content of the filler is 0 to 40 mass% of the mass of the resin solid content contained in the resin composition (2); the second insulating resin layer is disposed on both surfaces of the first insulating resin layer so as to be in contact with the first insulating resin layer; a metal foil is further disposed so as to be in contact with the surface of the second insulating resin layer opposite to the first insulating resin layer; <1> ~ <11> 10. The multilayer body according to any one of the preceding items. <12> the first insulating resin layer is a layer formed from a resin composition (1) and a fiber base material, and the resin composition (1) is in a cured state; the second insulating resin layer is a layer formed from a resin composition (2), and the resin composition (2) is in a cured state; The resin composition (1) contains a thermosetting compound, The resin composition (2) contains a thermosetting compound, and the content of the filler is 0 to 40 mass% of the mass of the resin solid content contained in the resin composition (2). <1> ~ <11> 10. The multilayer body according to any one of the preceding items. <13> providing metal wiring on the surface of the first insulating resin layer; providing a second insulating resin layer on the surface of the first insulating resin layer so as to cover the metal wiring; <1> ~ <12> 10. A method for producing a multilayer body according to any one of the above. <14> When providing metal wiring on the surface of the first insulating resin layer, a metal foil is provided on the surface of the first insulating resin layer opposite to the side on which the metal wiring is provided. <13> A method for producing a multilayer body according to claim 1. <15> After providing metal wiring on the surface of the first insulating resin layer, the metal foil on the surface of the first insulating resin layer opposite to the side on which the metal wiring is provided is removed, and metal wiring is provided on the surface of the first insulating resin layer on the side on which the metal wiring is not provided, or a second insulating resin layer is provided. <14> A method for producing a multilayer body according to claim 1. <16> <1> ~ <12> A printed wiring board comprising the multilayer body according to any one of the above. <17> <16> A semiconductor device comprising the printed wiring board according to claim 1. <18> <13> ~ <15> 10. A method for producing a printed wiring board, comprising the method for producing a multilayer body according to any one of the above items. [Effects of the Invention]

[0006] The present invention makes it possible to provide a multilayer body that can achieve reduced transmission loss and skew, as well as a multilayer body, a method for manufacturing a multilayer body, a printed wiring board, a semiconductor device, and a method for manufacturing a printed wiring board. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an example of a multilayer body (metal foil-clad laminate) according to an embodiment. [Figure 2] FIG. 2 is a schematic view showing another example of the multilayer body of the present embodiment. [Figure 3] FIG. 3 is a schematic diagram showing a method for producing a multilayer body according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the present embodiment is an example for explaining the present invention, and the present invention is not limited to only this embodiment. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the upper and lower limits. Furthermore, any combination of the upper and lower limit values ​​of the numerical values ​​in this specification is an example of this embodiment. In this specification, various physical properties and characteristic values ​​are those at 23°C unless otherwise specified. In the description of groups (atomic groups) in this specification, when a notation does not specify whether they are substituted or unsubstituted, it includes both groups (atomic groups) that have no substituents and groups (atomic groups) that have substituents. For example, the term "alkyl group" includes not only alkyl groups that have no substituents (unsubstituted alkyl groups) but also alkyl groups that have substituents (substituted alkyl groups). In this specification, when a notation does not specify whether they are substituted or unsubstituted, it is preferable that they be unsubstituted. Examples of the substituents herein include, preferably, a halogen atom, a cyano group, a nitro group, a hydroxy group, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic group, a heterocyclic oxy group, an alkenyl group, an alkylsulfanyl group, an arylsulfanyl group, an acyl group, or an amino group; more preferably, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an alkenyl group, or an acyl group; even more preferably, an alkyl group, an aryl group, an aryloxy group, or an alkenyl group; and even more preferably, an alkyl group. The formula weight of these substituents is preferably 15 or more and preferably 200 or less. For example, the formula weight of a methyl group (-CH3) is 15. These substituents may further have a substituent, but it is preferable that they have no substituent.

[0009] In this specification, "(meth)allyl" refers to both or either of allyl and methallyl, and "(meth)acrylic" refers to both or either of acrylic and methacrylic.

[0010] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. If the measurement methods, etc. described in the standards shown in this specification differ from year to year, they will be based on the standards in effect as of January 1, 2023, unless otherwise stated. If the measurement methods, etc. described in the standards shown in this specification are abolished as of January 1, 2023, they shall be based on the standards in effect at the time of abolition. The scale of Figures 1 to 3 may not be consistent with reality.

[0011] The term "semi-cured state" (semi-cured product) refers to a state between the uncured state and the cured state (fully cured state). When a semi-cured product is heated, it melts once and then becomes cured. Examples of the uncured state include a resin composition containing a solvent and a varnish. Examples of semi-cured states include resin solids in a prepreg formed from a resin composition (such as components from which the solvent in the resin composition has been removed), and resin solids in a metal foil-clad laminate containing the prepreg. Examples of the cured state include completely cured resin solids in a metal foil-clad laminate, and resin solids derived from a resin composition present in a printed wiring board. Furthermore, the layer formed from the resin composition may be in an uncured state, a semi-cured state, or a cured state. The resin composition is preferably in an uncured state, and the layer formed from the resin composition is preferably in a semi-cured state and / or a cured state.

[0012] In this specification, the resin solid content refers to components excluding fillers and solvents, and is intended to include thermosetting compounds, resin additives, and the like. In this specification, the terms relative permittivity and dielectric constant are used interchangeably.

[0013] The multilayer body of this embodiment includes a first insulating resin layer, metal wiring provided on the surface of the first insulating resin layer, and a second insulating resin layer provided on the surface of the first insulating resin layer and covering the metal wiring. The dielectric loss tangent of the second insulating resin layer at a frequency of 10 GHz measured using a perturbation cavity resonator is lower than the dielectric loss tangent of the first insulating resin layer at a frequency of 10 GHz measured using a perturbation cavity resonator. This configuration effectively reduces transmission loss in the metal wiring (particularly the metal wiring provided on the surface of the second insulating resin layer). This is presumably because the second insulating resin layer has a lower dielectric loss tangent, enabling efficient signal transmission even at high frequencies.

[0014] In this embodiment, the difference in dielectric tangent between the first insulating resin layer and the second insulating resin layer in contact with the first insulating resin layer is preferably 0.002 or more, more preferably 0.003 or more, even more preferably 0.004 or more, and preferably 0.01 or less. By making the difference equal to or greater than the lower limit, the dielectric tangent of the second insulating resin layer becomes relatively low, and the low transmission loss effect of the multilayer body tends to be further improved. Furthermore, by making the difference equal to or less than the upper limit, the thermal expansion characteristics of the first insulating resin layer become relatively low, and the low thermal expansion effect of the multilayer body tends to be further improved. When there are two second insulating resin layers in contact with the first insulating resin layer, the difference in dielectric tangent is defined as the difference between the values ​​of the second insulating resin layers with the larger difference in dielectric tangent, and it is preferable that both of the second insulating resin layers in contact with the first insulating resin layer satisfy the difference in dielectric tangent.

[0015] In this embodiment, the dielectric loss tangent of the first insulating resin layer is preferably 0.011 or less, more preferably 0.008 or less, and is usually greater than 0.004, and may even be greater than 0.008. In this embodiment, even if the dielectric loss tangent of the first insulating resin layer is somewhat high, the transmission loss of the entire multilayer body can be reduced, and therefore the first insulating resin layer can have a composition that provides even lower low thermal expansion.

[0016] In this embodiment, the dielectric loss tangent of the second insulating resin layer is preferably 0.011 or less, more preferably 0.008 or less, and even more preferably 0.004 or less. The lower limit of the dielectric loss tangent of the second insulating resin layer is the better, but even if it is 0.0001 or more, the required performance is sufficiently satisfied. The dielectric loss tangent is measured according to the method described in the examples below.

[0017] The thickness of the multilayer body of this embodiment is not particularly limited, but the total thickness of the first insulating resin layer, the second insulating resin layer, and the metal foil provided as needed is preferably 3000 μm or less, more preferably 2500 μm or less, even more preferably 2000 μm or less, and is preferably 100 μm or more, more preferably 150 μm or more, and even more preferably 200 μm or more. By setting the thickness to be below the above upper and lower limits, the dielectric loss tangent of the multilayer body tends to be lower.

[0018] In the multilayer body of this embodiment, it is preferable that the thickness of the second insulating resin layer is thinner than the thickness of the first insulating resin layer, because the skin effect is achieved in the second insulating resin layer, making it easier for electrical signals to pass through.

[0019] In the multilayer body of this embodiment, the ratio of the thickness of the first insulating resin layer to the thickness of the second insulating resin layer in contact with the first insulating resin layer is preferably 0.9 or less, more preferably 0.8 or less, even more preferably 0.7 or less, and even more preferably 0.6 or less, relative to the thickness of the first insulating resin layer. It is also preferably 0.0001 or more, more preferably 0.0005 or more, and even more preferably 0.00 or more. By setting the ratio at or below the upper limit, the dielectric loss tangent of the multilayer body tends to be lower. Furthermore, by setting the ratio at or above the lower limit, the dielectric loss tangent of the multilayer body tends to be lower and transmission loss tends to be more effectively suppressed. When two second insulating resin layers are in contact with the first insulating resin layer, the thickness of the thinner second insulating resin layer is defined as the thickness described above.

[0020] In the multilayer body of this embodiment, the thickness of the first insulating resin layer is preferably 5000 μm or less, more preferably 4000 μm or less, and even more preferably 3000 μm or less, and is preferably 100 μm or more, more preferably 150 μm or more, and even more preferably 200 μm or more.

[0021] In the multilayer body of this embodiment, the thickness of the second insulating resin layer is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 150 μm or less, and even more preferably 100 μm or less, and is preferably 1 μm or more, more preferably 3 μm or more, even more preferably 5 μm or more, and even more preferably 10 μm or more. By setting the thickness to the upper limit or less, the thermal expansion coefficient of the multilayer body tends to be lower. Furthermore, by setting the thickness to the lower limit or more, the transmission loss of the multilayer body tends to be lower.

[0022] Next, the layer structure of the multilayer body of this embodiment will be shown with reference to the drawings. FIG. 1 shows an example of a multilayer body (metal foil-clad laminate) of this embodiment, where 1 indicates the multilayer body, 2 indicates a first insulating resin layer, 3 indicates a second insulating resin layer in contact with the first insulating resin layer, 4 indicates metal wiring, and 5 indicates metal foil. In this embodiment, metal wiring 4 is provided on the surface of the first insulating resin layer 2, and further, a second insulating resin layer 3 is provided on the surface of the first insulating resin layer 2 so as to cover the metal wiring 4. In this embodiment, the metal foil 5 is not essential, and the multilayer body may be a multilayer body consisting of two layers, the first insulating resin layer 2 and the second insulating resin layer 3, and the metal wiring 4 therebetween, or a multilayer body consisting of three layers laminated in the order of second insulating resin layer 3 / metal wiring 4 / first insulating resin layer 2 / second insulating resin layer 3, or second insulating resin layer 3 / metal wiring 4 / first insulating resin layer 2 / metal wiring 4 / second insulating resin layer 3. Furthermore, other layers may be included within the scope of the present invention. In FIG. 1, the second insulating resin layers 3·3 are arranged so as to be in contact with both surfaces of the first insulating resin layer 2, and the metal wiring 4 is provided only on the surface of one of the first insulating resin layers 2, but the metal wiring 4 may be provided on both surfaces of the first insulating resin layer 2. In addition, in FIG. 1, metal foils 4 and 4 are disposed so as to contact the surfaces of the second insulating resin layers 3 and 3 opposite to the first insulating resin layer 2 . The configuration of FIG. 1 is suitable as a configuration for transporting materials before processing for printed wiring boards (particularly for circuit boards). The multilayer body of this embodiment does not necessarily have to have a second insulating resin layer 3 and a metal foil 4 provided on both sides of a single first insulating resin layer, as shown in FIG. 1 . For example, a second insulating resin layer may be provided on one side of a single first insulating resin layer, or a second insulating resin layer may be provided on one side of a single first insulating resin layer, with a metal foil further disposed in contact with the surface of the second insulating resin layer opposite the first insulating resin layer. Furthermore, the two second insulating resin layers 3 in FIG. 1 may be the same layer, or may be second insulating resin layers with different thicknesses and / or compositions. The same applies to the metal wiring and metal foil.

[0023] 2 shows another example of the multilayer body of this embodiment, in which metal wiring 4 and a second insulating resin layer 3 are provided on the surface of a first insulating resin layer 2, but no metal foil is provided. This type of configuration can be preferably formed by peeling off the metal foil (not shown) on the surface of the second insulating resin layer 3, and then providing the metal wiring 4. The metal wiring can be formed by a known method such as a subtractive method or a (semi-)additive method. 2, the surface of the second insulating resin layer 3 further has metal wiring 4, and further has a new second insulating resin layer 3. Such a multilayer body is preferably used as a circuit board. The second second insulating resin layer may be a layer having the same composition and thickness as the first second insulating resin layer, or may have a different composition and / or thickness. In either case, the second second insulating resin layer is preferably made of the same material as the material of the second insulating resin layer described below.

[0024] An example of an embodiment of the multilayer body of this embodiment is when the multilayer body is used in an application requiring a low coefficient of thermal expansion. One of the performance requirements for printed wiring boards is a low coefficient of thermal expansion. Furthermore, suppression of warpage during heating is also sometimes required. When the multilayer body of this embodiment is used in applications requiring these performances, the coefficient of thermal expansion of the first insulating resin layer, measured in accordance with the TMA (Thermo-mechanical analysis) method, is preferably 30 ppm / °C or less. Because the first insulating resin layer has such a low coefficient of thermal expansion, even if the second insulating resin layer has a high coefficient of thermal expansion, an increase in the coefficient of thermal expansion of the multilayer body can be suppressed, and warpage of the multilayer body can also be suppressed. As a result, it is possible to impart other functions (further low dielectric properties (Dk and / or Df)) to the second insulating resin layer in addition to low thermal expansion and low warpage. The thermal expansion coefficient referred to here is measured in accordance with the TMA method (Thermo-Mechanical Analysis) specified in JIS C 6481 5.19, and refers to the thermal expansion coefficient in the in-plane direction (CTE(XY)) from 50°C to 280°C when the temperature is increased from 30°C to 320°C at a rate of 10°C per minute, and more specifically, is measured by the method described in the examples.

[0025] Therefore, the thermal expansion coefficient of the first insulating resin layer is preferably 30 ppm / ° C. or less, more preferably 25 ppm / ° C. or less, even more preferably 20 ppm / ° C. or less, even more preferably 15 ppm / ° C. or less, and still more preferably 10 ppm / ° C. or less. The lower limit of the thermal expansion coefficient of the first insulating resin layer is preferably 0 ppm / ° C., but even if it is 1 ppm / ° C. or more, the required performance is sufficiently met.

[0026] The low thermal expansion coefficient of the first insulating resin layer can be achieved, for example, by increasing the proportion of filler in the first insulating resin layer (e.g., greater than the proportion of filler in the second insulating resin layer). That is, by reducing the proportion of resin components that are prone to thermal expansion in the first insulating resin layer, the thermal expansion of the first insulating resin layer can be effectively suppressed. The first insulating resin layer preferably contains a fiber base material. Details of the composition of the first insulating resin layer will be described later.

[0027] On the other hand, insulating resin layers containing fillers, particularly fibrous substrates, tend to have uneven surfaces, resulting in variations in electronic signals. Therefore, when the first insulating resin layer contains a filler, particularly a fibrous substrate, it is preferable that the second insulating resin layer does not contain a filler (particularly a fibrous substrate). This configuration results in a smooth surface, making it possible to more effectively reduce the transmission loss of the resulting multilayer body. Details of the composition of the second insulating resin layer will be described later. In this case, the second insulating resin layer tends to have a smaller amount of filler than the first insulating resin layer, and therefore preferably does not contain a fiber substrate. Therefore, the thermal expansion coefficient of the second insulating resin layer usually tends to be higher than that of the first insulating resin layer. The thermal expansion coefficient of the second insulating resin layer may be, for example, greater than 10 ppm / °C, or even greater than 15 ppm / °C, and is preferably 30 ppm / °C or less.

[0028] <First insulating resin layer> The dielectric loss tangent of the first insulating resin layer in this embodiment is not particularly specified as long as it is equal to or greater than that of the second insulating resin layer at a frequency of 10 GHz measured using a perturbation method cavity resonator (preferably greater than that of the second insulating resin layer). The first insulating resin layer is usually a layer formed from a resin composition (1) containing a thermosetting compound and a fiber substrate, or a layer formed from a resin composition (1) containing a thermosetting compound, and is preferably a layer formed from a resin composition (1) containing a thermosetting compound and a fiber substrate. In the layer formed from the resin composition (1), the resin solid content contained in the resin composition (1) may be in an uncured state, a semi-cured state, or a cured state. Preferably, the resin solid content contained in the resin composition (1) is in a semi-cured state or a cured state.

[0029] The thermosetting compound contained in the resin composition (1) is preferably a thermosetting compound containing at least one group selected from the group consisting of (meth)allyl compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, phenolic compounds, oxetane compounds, benzoxazine compounds, compounds having a polymerizable unsaturated group other than the above compounds, silicone-modified thermosetting compounds, and BT resins. BT resin is a polymer made from a cyanate ester compound and a maleimide compound. The thermosetting compounds may include, for example, epoxy compounds containing a (meth)allyl group. For such compounds, compounds specified in any of the items described below, such as "(meth)allyl compounds," are classified into the specified item (e.g., (meth)allyl compounds). Compounds not specified in any of the items are classified into the compounds described in the preceding paragraphs of this specification.

[0030] The total amount of the thermosetting compounds in the resin composition (1) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, still more preferably 50 parts by mass or more, even more preferably 70 parts by mass or more, and is preferably 99 parts by mass or less, more preferably 95 parts by mass or less, even more preferably 90 parts by mass or less, relative to 100 parts by mass of the resin solid content. The resin composition (1) may contain only one type of thermosetting compound or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0031] A first example of a blend form of the thermosetting compound in the resin composition (1) is a form containing at least one compound selected from (meth)allyl compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, phenol compounds, benzoxazine compounds, and compounds having a polymerizable unsaturated group other than the above compounds, and at least one silicone-modified thermosetting compound. A first example of a blend form of the thermosetting compound in the resin composition (1) more preferably contains at least one selected from a (meth)allyl compound, a maleimide compound, an epoxy compound, and a cyanate ester compound, and at least one silicone-modified thermosetting compound.

[0032] In the first example of the blend form of the thermosetting compound in the resin composition (1), the content of the silicone-modified thermosetting compound is preferably 1 part by mass or more, and is preferably 50 parts by mass or less, and more preferably 10 parts by mass or less, per 100 parts by mass of the resin solid content. In a first example of the blend form of thermosetting compounds in the resin composition (1), the content of the thermosetting compound other than the silicone-modified thermosetting compound is preferably 10 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 70 parts by mass or more, and is preferably 99 parts by mass or less, more preferably 95 parts by mass or less, relative to 100 parts by mass of the resin solid content. Here, the thermosetting compound other than the silicone-modified thermosetting compound is preferably at least one selected from (meth)allyl compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, phenol compounds, benzoxazine compounds, and compounds having a polymerizable unsaturated group other than the above compounds.

[0033] A second example of the blend form of the thermosetting compound in resin composition (1) is a form containing one or more selected from the group consisting of (meth)allyl compounds, maleimide compounds, epoxy compounds, cyanate ester compounds, phenolic compounds, benzoxazine compounds, compounds having a polymerizable unsaturated group other than the above compounds, and BT resins. The second example preferably contains one or more selected from the group consisting of maleimide compounds, epoxy compounds, cyanate ester compounds, phenolic compounds, and BT resins in a total amount of 90 parts by mass or more per 100 parts by mass of the resin solid content. In the second example of the blend form of the thermosetting compounds in the resin composition (1), it is preferable that the maleimide compound is contained in an amount of 3 to 50 parts by mass relative to 100 parts by mass of the total amount of the thermosetting compounds. In the second example of the blend form of the thermosetting compounds in the resin composition (1), it is preferable that the epoxy compound is contained in an amount of 10 to 80 parts by mass relative to 100 parts by mass of the total amount of the thermosetting compounds. In the second example of the blend form of the thermosetting compounds in the resin composition (1), it is preferable that the cyanate ester compound is contained in an amount of 10 to 60 parts by mass relative to 100 parts by mass of the total amount of the thermosetting compounds. In the second example of the blend form of the thermosetting compounds in the resin composition (1), it is preferable that the phenol compound is contained in an amount of 10 to 60 parts by mass relative to 100 parts by mass of the total amount of the thermosetting compounds. In the second example of the blend form of the thermosetting compounds in the resin composition (1), it is preferable that the BT resin is contained in an amount of 20 to 80 parts by mass relative to 100 parts by mass of the total amount of the thermosetting compounds. In the second example of the blend form of the thermosetting compound in the resin composition (1), it is preferable that the resin composition (1) is substantially free of a silicone-modified thermosetting compound. "Substantially free" means that the content of the silicone-modified thermosetting compound in the resin composition (1) is less than 3 parts by mass, preferably less than 1 part by mass, and may be less than 0.1 parts by mass, per 100 parts by mass of the resin solid content. These thermosetting compounds will be described in detail below.

[0034] <<(Meth)allyl compounds>> The (meth)allyl compound is not particularly limited as long as it is a compound having one or more (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, even more preferably 2 or 3, and still more preferably 2) (meth)allyl groups in one molecule, and a wide range of (meth)allyl compounds commonly used in the field of printed wiring boards can be used. In this embodiment, the (meth)allyl compound is preferably an allyl compound.

[0035] An example of a (meth)allyl compound is a (meth)allyl phenol compound. The (meth)allyl phenol compound preferably has one or more structures in which one or more (meth)allyl groups are directly bonded to a phenolic aromatic ring. The (meth)allyl phenol compound preferably has one or two structures in which one or more (meth)allyl groups are directly bonded to a phenolic aromatic ring, and more preferably has two structures.

[0036] The (meth)allylphenol compound may be, for example, a compound represented by formula (1A) or formula (1B). [ka] (In formula (1A), each Rxa independently represents a (meth)allyl group, each Rxb independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom, each Rxc independently represents an aromatic ring having 4 to 12 carbon atoms, Rxc may form a condensed structure with a benzene ring, Rxc may or may not be present, A represents an alkylene group having 1 to 6 carbon atoms, an aralkylene group having 7 to 16 carbon atoms, an arylene group having 6 to 10 carbon atoms, a fluorenylidene group, a sulfonyl group, an oxygen atom, a sulfur atom, or a direct bond (single bond), and when Rxc is not present, one benzene ring may have two or more Rxa and / or Rxb groups.) [ka] (In formula (1B), each Rxd independently represents a (meth)allyl group, each Rxe independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom, and Rxf represents an aromatic ring having 4 to 12 carbon atoms, which may form a condensed structure with a benzene ring, and which may or may not be present, and when Rxf is not present, one benzene ring may have two or more Rxd and / or Rxe groups.)

[0037] In the formulas (1A) and (1B), when the groups represented by Rxc and Rxf form a condensed structure with a benzene ring, for example, a compound containing a naphthol ring as a phenolic aromatic ring can be mentioned. In addition, in the formulas (1A) and (1B), when the groups represented by Rxc and Rxf do not exist, for example, a compound containing a phenol ring as a phenolic aromatic ring can be mentioned.

[0038] In formula (1A) and formula (1B), the alkyl group having 1 to 10 carbon atoms represented by Rxb and Rxe is not particularly limited, and examples thereof include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, and branched alkyl groups such as an isopropyl group, an isobutyl group, and a tert-butyl group.

[0039] In formula (1A), the alkylene group having 1 to 6 carbon atoms represented by A is not particularly limited, and examples thereof include a methylene group, an ethylene group, a trimethylene group, and a propylene group. The aralkylene group having 7 to 16 carbon atoms represented by A is not particularly limited, and examples thereof include groups represented by the formula: -CH2-Ar-CH2-, -CH2-CH2-Ar-CH2-CH2-, or -CH2-Ar-CH2-CH2- (wherein Ar represents a phenylene group, a naphthylene group, or a biphenylene group). The arylene group having 6 to 10 carbon atoms represented by A is not particularly limited, and examples thereof include a phenylene ring.

[0040] In the compound represented by formula (1B), Rxf is preferably a benzene ring (a compound containing a dihydroxynaphthalene skeleton).

[0041] From the viewpoint of further improving compatibility, the (meth)allyl phenol compound is preferably (meth)allyl bisphenol in which one (meth)allyl group is bonded to each of two phenolic aromatic rings of a bisphenol. From the same viewpoint, the (meth)allyl bisphenol is preferably diallyl bisphenol in which one (meth)allyl group is bonded to each of two phenolic aromatic rings of a bisphenol, and / or dipropenyl bisphenol in which one propenyl group is bonded to each of two phenolic aromatic rings of a bisphenol.

[0042] The diallyl bisphenol is not particularly limited, but examples thereof include o,o'-diallyl bisphenol A ("DABPA" manufactured by Daiwa Chemical Industry Co., Ltd.), o,o'-diallyl bisphenol F, o,o'-diallyl bisphenol S, and o,o'-diallyl bisphenol fluorene. The dipropenyl bisphenol is not particularly limited, but examples thereof include o,o'-dipropenyl bisphenol A ("PBA01" manufactured by Gunei Chemical Industry Co., Ltd.), o,o'-diallyl bisphenol F, o,o'-dipropenyl bisphenol S, and o,o'-dipropenyl bisphenol fluorene.

[0043] The average number of phenol groups per molecule of the (meth)allylphenol compound is preferably 1 or more and less than 3, and more preferably 1.5 or more and 2.5 or less. The average number of phenol groups is calculated by the following formula.

number

[0044] In the formula, Ai represents the number of phenol groups in an alkenylphenol having i phenol groups in the molecule, Xi represents the proportion of alkenylphenols having i phenol groups in the molecule to all alkenylphenols, and X1 + X2 + ... Xn = 1.

[0045] Another example of the (meth)allyl compound is a (meth)allyl-substituted nadimide compound. The (meth)allyl-substituted nadimide compound is not particularly limited as long as it is a compound having one or more (meth)allyl-substituted nadimide groups in one molecule, and examples thereof include compounds represented by formula (2d).

[0046] [ka]

[0047] In formula (2d), R1's each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (e.g., a methyl group or an ethyl group), and R2's each independently represent an alkylene group having 1 to 6 carbon atoms, a phenylene group, a biphenylene group, a naphthylene group, or a group represented by the following formula (7) or (8):

[0048] [ka]

[0049] In formula (7), R3 represents a methylene group, an isopropylidene group, -C(=O)-, -O-, -S- or -SO2-.

[0050] [ka] In formula (8), each R4 independently represents an alkylene group having 1 to 4 carbon atoms or a cycloalkylene group having 5 to 8 carbon atoms.

[0051] The (meth)allyl-substituted nadimide compound represented by formula (2d) may be a commercially available product, or a product produced in accordance with formula m. Examples of commercially available products include "BANI-M" and "BANI-X" manufactured by Maruzen Petrochemical Co., Ltd.

[0052] In addition to the above, for details of the (meth)allyl compound, please refer to the descriptions in paragraphs 0016 to 0030 of WO 2020 / 022084 and paragraphs 0141 to 0160 of WO 2023 / 013709, the contents of which are incorporated herein by reference.

[0053] When the resin composition (1) contains a (meth)allyl compound, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the resin solid content, and is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. The resin composition (1) may contain only one (meth)allyl compound, or may contain two or more (meth)allyl compounds. When two or more (meth)allyl compounds are contained, the total amount is preferably within the above range.

[0054] <<Maleimide compounds>> The maleimide compound is not particularly limited as long as it is a compound having one or more (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and even more preferably 2) maleimide groups in one molecule, and a wide range of maleimide compounds commonly used in the field of printed wiring boards can be used.

[0055] Examples of the maleimide compound include maleimide compounds that may be incorporated into resin composition (2) described later, and preferably include one or more selected from the group consisting of compounds represented by formula (M0), compounds represented by formula (M1), compounds represented by formula (M2), compounds represented by formula (M3), compounds represented by formula (M4), compounds represented by formula (M5), maleimide compounds (M6), maleimide compounds (M7), and maleimide compounds (M8), which are described in resin composition (2) described later. More preferably, the maleimide compound includes one or more selected from the group consisting of compounds represented by formula (M0), compounds represented by formula (M2), compounds represented by formula (M3), compounds represented by formula (M4), and compounds represented by formula (M5). More preferably, the maleimide compound includes a compound represented by formula (M2) and / or a compound represented by formula (M3).

[0056] In addition to the above, for details of the maleimide compound, see paragraphs 0092 to 0095 of International Publication No. 2020 / 022084, paragraphs 0103 to 0110 of International Publication No. 2023 / 013709, and paragraphs 0044 to 0045 of Japanese Patent No. 6414799. The contents of these references are incorporated herein by reference.

[0057] When the resin composition (1) contains a maleimide compound, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content, and is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. The resin composition (1) may contain only one maleimide compound or may contain two or more maleimide compounds. When two or more maleimide compounds are contained, the total amount is preferably within the above range.

[0058] <<Epoxy compounds>> The epoxy compound is not particularly limited as long as it is a compound having one or more (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and even more preferably 2) epoxy groups in one molecule, and a wide range of epoxy compounds commonly used in the field of printed wiring boards can be used.

[0059] It should be noted that epoxy-modified silicones, which will be described separately below, are not included in the epoxy compounds in this section.

[0060] Examples of epoxy compounds include bisphenol-type epoxy resins (e.g., bisphenol A-type epoxy resins, bisphenol E-type epoxy resins, bisphenol F-type epoxy resins, and bisphenol S-type epoxy resins), diallyl bisphenol-type epoxy resins (e.g., diallyl bisphenol A-type epoxy resins, diallyl bisphenol E-type epoxy resins, diallyl bisphenol F-type epoxy resins, and diallyl bisphenol S-type epoxy resins), phenol novolac-type epoxy resins (e.g., phenol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, and cresol novolac-type epoxy resins), aralkyl-type epoxy resins, biphenyl-type epoxy resins containing a biphenyl skeleton, naphthalene-type epoxy resins containing a naphthalene skeleton, anthracene-type epoxy resins containing a dihydroanthracene skeleton, glycidyl esters, polyol-type epoxy resins, isocyanurate ring-containing epoxy resins, dicyclopentadiene-type epoxy resins, epoxy resins consisting of bisphenol A-type structural units and hydrocarbon-based structural units, and halogen compounds thereof. These epoxy compounds may be used alone or in combination of two or more.

[0061] Among these, from the viewpoint of further improving chemical resistance, copper foil adhesion, and insulation reliability, the epoxy compound is preferably at least one selected from the group consisting of aralkyl epoxy resins, naphthalene epoxy resins, dicyclopentadiene epoxy resins, and epoxy resins comprising bisphenol A structural units and hydrocarbon-based structural units, and more preferably contains a naphthalene epoxy resin.

[0062] <<<Aralkyl type epoxy resin>>> The aralkyl epoxy resin is not particularly limited, but examples thereof include compounds represented by formula (3a). [ka] (In formula (3a), Ar 3 each independently represents a benzene ring or a naphthalene ring; Ar 4 represents a benzene ring, a naphthalene ring, or a biphenyl ring, and R 3a each independently represents a hydrogen atom or a methyl group, k represents an integer of 1 to 50, and each ring may have a substituent other than a glycidyloxy group (for example, an alkyl group having 1 to 5 carbon atoms or a phenyl group).

[0063] The compound represented by formula (3a) is Ar 3 is a naphthalene ring, and Ar 4 is a benzene ring (also called "naphthalene aralkyl type epoxy resin"), and Ar 3 is a benzene ring, and Ar 4 is a biphenyl ring (also referred to as a "biphenyl aralkyl type epoxy resin"), and a biphenyl aralkyl type epoxy resin is more preferred.

[0064] The biphenylaralkyl epoxy resin is preferably a compound represented by formula (3b). [ka] (In formula (3b), ka represents an integer of 1 or more, preferably 1 to 20, and more preferably 1 to 6.)

[0065] The aralkyl epoxy resin may also be a compound represented by formula (3c). [ka] (In formula (3c), ky represents an integer of 1 to 10.)

[0066] The aralkyl epoxy resin may be a commercially available product, or a preparation prepared by a known method may be used. Commercially available naphthalene aralkyl epoxy resins include Nippon Steel & Sumikin Chemical Co., Ltd.'s "Epotohto (registered trademark) ESN-155," "Epotohto (registered trademark) ESN-355," "Epotohto (registered trademark) ESN-375," "Epotohto (registered trademark) ESN-475V," "Epotohto (registered trademark) ESN-485," and "Epotohto (registered trademark) ESN-175," Nippon Kayaku Co., Ltd.'s "NC-7000," "NC-7300," and "NC-7300L," and DIC Corporation's "HP-5000" and "HP-9900." Commercially available biphenyl aralkyl epoxy resins include Nippon Kayaku Co., Ltd.'s "NC-3000," "NC-3000L," and "NC-3000FH."

[0067] <<<Naphthalene-type epoxy resin>>> The naphthalene-type epoxy resin is not particularly limited, but examples thereof include naphthalene-skeleton-containing polyfunctional epoxy resins having a naphthalene skeleton represented by the following formula (3-1), and epoxy resins having a naphthalene skeleton, excluding the above-mentioned naphthalene aralkyl-type epoxy resins. Specific examples of naphthalene-type epoxy resins include naphthylene ether-type epoxy resins, and naphthylene ether-type epoxy resins are preferred from the viewpoint of further improving chemical resistance, copper foil adhesion, and insulation reliability. [ka] (In formula (3-1), Ar 31 each independently represents a benzene ring or a naphthalene ring; Ar 41 represents a benzene ring, a naphthalene ring, or a biphenyl ring, and R 31a each independently represents a hydrogen atom or a methyl group; p represents an integer of 0 to 2, preferably 0 or 1; kz represents an integer of 1 to 50; each ring may have a substituent other than a glycidyloxy group (for example, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or a phenyl group); Ar 31 and Ar 41 At least one of the groups represents a naphthalene ring. The compound represented by formula (3-1) includes a compound represented by formula (3-2). [ka] (In formula (3-1), R represents a methyl group, and kz has the same meaning as kz in the above formula (3-1).)

[0068] The naphthalene skeleton-containing polyfunctional epoxy resin may be a commercially available product or a product prepared by a known method. Examples of commercially available naphthalene skeleton-containing polyfunctional epoxy resins include "HP-9540" and "HP-9500" manufactured by DIC Corporation.

[0069] From the viewpoint of further improving chemical resistance, copper foil adhesion, and insulation reliability, the naphthylene ether type epoxy resin is preferably a compound represented by formula (3-3) or a compound represented by formula (3-4). [ka] (In the formula, R 13 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group or an ethyl group), or an alkenyl group having 2 to 3 carbon atoms (e.g., a vinyl group, an allyl group, or a propenyl group). [ka] (In formula (3-3), R 14 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms (e.g., a methyl group or an ethyl group), or an alkenyl group having 2 to 3 carbon atoms (e.g., a vinyl group, an allyl group, or a propenyl group).

[0070] The naphthylene ether type epoxy resin may be a commercially available product or a product prepared by a known method. Examples of commercially available naphthylene ether type epoxy resins include "HP-6000", "EXA-7300", "EXA-7310", "EXA-7311", "EXA-7311L", "EXA7311-G3", "EXA7311-G4", "EXA-7311G4S", and "EXA-7311G5" manufactured by DIC Corporation.

[0071] <<<Dicyclopentadiene type epoxy resin>>> The dicyclopentadiene type epoxy resin is not particularly limited, but examples thereof include compounds represented by formula (3-5). [ka] (In the formula, R 3c each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and k2 represents an integer of 0 to 10.

[0072] The dicyclopentadiene-type epoxy resin may be a commercially available product or a preparation prepared by a known method. Commercially available dicyclopentadiene-type epoxy resins include "EPICRON HP-7200L," "EPICRON HP-7200," "EPICRON HP-7200H," and "EPICRON HP-7000HH" manufactured by Dainippon Ink and Chemicals, Inc.

[0073] <<<Epoxy resins consisting of bisphenol A structural units and hydrocarbon structural units>>> An epoxy resin composed of bisphenol A structural units and hydrocarbon-based structural units (also referred to as a "specific epoxy resin") has one or more bisphenol A structural units and one or more hydrocarbon-based structural units in the molecule. An example of the specific epoxy resin is a compound represented by the following formula (3e): [ka] (In the formula, R 1x and R 2x each independently represents a hydrogen atom or a methyl group, R 3x ~R 6x each independently represents a hydrogen atom, a methyl group, a chlorine atom, or a bromine atom; X represents an ethyleneoxyethyl group, a di(ethyleneoxy)ethyl group, a tri(ethyleneoxy)ethyl group, a propyleneoxypropyl group, a di(propyleneoxy)propyl group, a tri(propyleneoxy)propyl group, or an alkylene group having 2 to 15 carbon atoms; and k3 represents a natural number.

[0074] k3 represents a natural number, preferably 1 to 100, and more preferably 1 to 10.

[0075] The specific epoxy resin may be a commercially available product or a product prepared by a known method. Examples of commercially available specific epoxy resins include "EPICLON EXA-4850-150" and "EPICLON EXA-4816" manufactured by DIC Corporation.

[0076] In addition to the above, for details of the epoxy compound, see paragraphs 0117 to 0133 of International Publication No. 2020 / 022084, paragraphs 0189 to 0214 of International Publication No. 2023 / 013709, and paragraphs 0047 to 0053 of Japanese Patent No. 6414799. The contents of these references are incorporated herein by reference.

[0077] When the resin composition (1) contains an epoxy compound, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content, and is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. The resin composition (1) may contain only one type of epoxy compound, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0078] <<Cyanate ester compounds>> The cyanate ester compound is not particularly limited as long as it is a compound having two or more cyanato groups (cyanate ester groups) in one molecule, and examples thereof include naphthol aralkyl cyanate ester compounds such as compounds represented by formula (5), novolak cyanate ester compounds such as compounds represented by formula (6) excluding compounds represented by formula (5), biphenyl aralkyl cyanate esters, diallyl bisphenyl cyanate ester compounds, bis(3,3-dimethyl-4-cyanatophenyl)methane, bis(4-cyanatophenyl)methane, 1,3-dicyanato Examples include benzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, and 2,2-bis(4-cyanatophenyl)propane. These cyanate ester compounds may be used alone or in combination of two or more. Among these, from the viewpoint of further improving the low thermal expansion and chemical resistance of the first insulating resin layer, the cyanate ester compound preferably includes a naphthol aralkyl cyanate ester compound and / or a novolac cyanate ester compound, and more preferably includes a compound represented by formula (5).

[0079] [ka] (In formula (5), each R6 independently represents a hydrogen atom or a methyl group, and n2 represents an integer of 1 or greater.) n2 is preferably an integer of 1 to 20, more preferably an integer of 1 to 10, and even more preferably an integer of 1 to 6.

[0080] [ka] (In formula (6), R ya each independently represents a (meth)allyl group having 2 to 8 carbon atoms or a hydrogen atom, and R yb each independently represents an alkyl group having 1 to 10 carbon atoms or a hydrogen atom, and R yc each independently represents an aromatic ring having 4 to 12 carbon atoms; R yc may form a condensed structure with a benzene ring, and R yc may or may not be present, and A 1a each independently represents an alkylene group having 1 to 6 carbon atoms, an aralkylene group having 7 to 16 carbon atoms, an arylene group having 6 to 10 carbon atoms, a fluorenylidene group, a sulfonyl group, an oxygen atom, a sulfur atom, or a single bond (direct bond), and R yc If there is no R in one benzene ring, ya and / or R yb The group may have two or more of the following groups. n represents an integer of 1 to 20.

[0081] In formula (6), R ya Examples of the (meth)allyl group having 2 to 8 carbon atoms represented by the following formula include a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group.

[0082] In formula (6), R ybExamples of the alkyl group having 1 to 10 carbon atoms represented by the formula (I) include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group; and branched alkyl groups such as an isopropyl group, an isobutyl group, and a tert-butyl group.

[0083] In formula (6), A 1a Examples of the alkylene group having 1 to 6 carbon atoms represented by the formula (6) include a methylene group, an ethylene group, a trimethylene group, and a propylene group. 1a Examples of the aralkylene group having 7 to 16 carbon atoms represented by the formula include groups represented by the formula: -CH2-Ar-CH2-, -CH2-CH2-Ar-CH2-CH2-, or -CH2-Ar-CH2-CH2- (wherein Ar represents a phenylene group, a naphthylene group, or a biphenylene group). 1a Examples of the arylene group having 6 to 10 carbon atoms represented by the following formula include a phenylene ring.

[0084] In formula (6), n represents an integer of 1 to 20, preferably an integer of 1 to 15, and more preferably an integer of 1 to 10.

[0085] The compound represented by formula (6) is preferably a phenol novolac cyanate ester compound, and more preferably a compound represented by formula (c1), because it further improves the low thermal expansion and chemical resistance of the first insulating resin layer and has a higher glass transition temperature.

[0086] [ka]

[0087] In formula (c1), each Rx independently represents a hydrogen atom or a methyl group, each R independently represents an alkenyl group having 2 to 8 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a hydrogen atom, and n represents an integer of 1 to 10.

[0088] These cyanate ester compounds may be produced according to known methods, such as those described in JP-A-2017-195334 (particularly paragraphs 0052 to 0057).

[0089] In addition to the above, in this embodiment, the cyanate ester compounds described in WO 2021 / 172317 can be used, the contents of which are incorporated herein by reference.

[0090] The relative dielectric constant at a frequency of 10 GHz of the cured product of the cyanate ester compound used in this embodiment, measured according to the cavity resonance perturbation method, is preferably 3.0 or less, more preferably 2.9 or less, and even more preferably less than 2.9, and a practical lower limit value is 2.4 or more.

[0091] When the resin composition (1) contains a cyanate ester compound, the lower limit of its content is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition (1). A cyanate ester compound content of 0.1 parts by mass or more tends to improve the adhesion of the first insulating resin layer to the metal foil (plating layer and / or wiring pattern), fine wiring formability, heat resistance, flame resistance, chemical resistance, low dielectric properties (dielectric constant and / or dielectric dissipation factor), and insulating properties. The upper limit of the cyanate ester compound content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition (1). It may be 8 parts by mass or less, or 6 parts by mass or less, depending on the intended use. The resin composition (1) in the present embodiment may contain only one type of cyanate ester compound, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0092] <<Phenol compounds>> The phenolic compound is not particularly limited as long as it has two or more phenolic hydroxyl groups per molecule. Examples include phenols having two or more phenolic hydroxyl groups per molecule, bisphenols (e.g., bisphenol A, bisphenol E, bisphenol F, bisphenol S, etc.), diallyl bisphenols (e.g., diallyl bisphenol A, diallyl bisphenol E, diallyl bisphenol F, diallyl bisphenol S, etc.), phenol novolac resins (e.g., phenol novolac resin, naphthol novolac resin, cresol novolac resin, etc.), naphthalene phenolic resins, dihydroanthracene phenolic resins, dicyclopentadiene phenolic resins, biphenyl phenolic resins, and aralkyl phenolic resins. These phenolic compounds may be used alone or in combination. Among these, the phenolic compound preferably contains an aralkyl phenolic resin from the viewpoint of further improving copper foil adhesion.

[0093] <<<Aralkyl phenolic resin>>> An example of the aralkyl phenol resin is a compound represented by formula (c2). [ka] (In formula (c2), Ar 1 each independently represents a benzene ring or a naphthalene ring, and Ar 2 represents a benzene ring, a naphthalene ring, or a biphenyl ring, and R 2a are each independently a hydrogen atom or a methyl group, m is an integer of 1 to 50, and each ring may have a substituent other than a hydroxyl group. The substituent is, for example, an alkyl group having 1 to 5 carbon atoms or a phenyl group.

[0094] The compound represented by formula (c2) is, from the viewpoint of further improving the metal foil adhesion of the first insulating resin layer, 1 is a naphthalene ring, and A2 is a benzene ring (hereinafter also referred to as "naphthol aralkyl phenolic resin"), and 1 is a benzene ring, and Ar 2 is a biphenyl ring (hereinafter also referred to as "biphenylaralkyl type phenol resin").

[0095] The naphthol aralkyl phenol resin is preferably a compound represented by formula (2b).

[0096] [ka] (In formula (2b), R 2a each independently represents a hydrogen atom or a methyl group, and m represents an integer of 1 to 10.

[0097] In formula (2b), R 2a preferably represents a hydrogen atom, and m preferably represents an integer of 1 to 6.

[0098] The biphenylaralkyl phenol resin is preferably a compound represented by formula (2c). [ka] (In formula (2c), R 2b each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a phenyl group; m1 represents an integer of 1 to 20;

[0099] In formula (2c), R 2b preferably represents a hydrogen atom, and m1 preferably represents an integer of 1 to 6.

[0100] The aralkyl phenol resin may be a commercially available product, or a product produced by a known method. Commercially available aralkyl phenol resins include "KAYAHARD GPH-65," "KAYAHARD GPH-78," and "KAYAHARD GPH-103" (biphenyl aralkyl phenol resins) manufactured by Nippon Kayaku Co., Ltd., and "SN-495" (naphthol aralkyl phenol resin) manufactured by Nippon Steel Chemical Co., Ltd.

[0101] When the resin composition (1) contains a phenol compound, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content, and is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. The resin composition (1) may contain only one type of phenol compound, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0102] <<Other thermosetting compounds>> Examples of the polymerizable compound include oxetane compounds, benzoxazine compounds, and compounds having a polymerizable unsaturated group. For details of these resins, please refer to paragraphs 0135 to 0138 of WO 2020 / 022084, paragraphs 0036 to 0039 of WO 2023 / 013709, and paragraphs 0066 to 0069 and 0094 to 0106 of WO 2023 / 171553, the contents of which are incorporated herein by reference.

[0103] <<Silicone-modified thermosetting compounds>> The resin composition (1) may contain a silicone-modified thermosetting compound containing at least one group selected from the group consisting of a maleimide group, an amino group, an epoxy group, a carboxy group, a vinyl group, a hydroxy group, and a (meth)acrylic group, and a polysiloxane structure. The silicone-modified thermosetting compound preferably has a polysiloxane skeleton in which siloxane bonds are repeatedly formed in the molecule, and contains at least one group selected from the group consisting of a maleimide group, an amino group, an epoxy group, a carboxy group, a vinyl group, a hydroxy group, and a (meth)acrylic group.

[0104] <<<Epoxy-modified silicone>>> A first embodiment of the silicone-modified thermosetting compound is a silicone compound having an epoxy group (hereinafter, sometimes referred to as "epoxy-modified silicone"). The epoxy-modified silicone is not particularly limited as long as it is a silicone compound or resin modified with an epoxy group-containing group. By containing the epoxy-modified silicone, the resin composition (1) can exhibit excellent low thermal expansion and chemical resistance for the first insulating resin layer.

[0105] The polysiloxane structure may be a linear silicone structure, a cyclic silicone structure, or a network silicone structure. In this embodiment, a linear silicone structure is preferred.

[0106] The epoxy group-containing group is not particularly limited, but examples thereof include groups represented by the following formula (a1): [ka] (In formula (a1), R 0 represents an alkylene group (for example, an alkylene group having 1 to 5 carbon atoms such as a methylene group, an ethylene group, or a propylene group), and X represents a monovalent group represented by the following formula (a2) or a monovalent group represented by the following formula (a3): [ka] [ka]

[0107] In the formula (a1), the alkylene group is preferably an alkylene group having 1 to 5 carbon atoms, such as a methylene group, an ethylene group, or a propylene group. Preferred examples of the epoxy compound used in the epoxy-modified silicone include the epoxy compounds described above in the section <<Epoxy Compounds>>.

[0108] The epoxy-modified silicone preferably contains an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g / mol. By containing an epoxy-modified silicone having an epoxy equivalent within the above range, the compatibility with thermosetting compounds, low thermal expansion, and chemical resistance tend to be further improved in a well-balanced manner. From the same viewpoint, the epoxy equivalent is more preferably 145 to 245 g / mol, and even more preferably 150 to 240 g / mol.

[0109] The epoxy-modified silicone preferably contains two or more types of epoxy-modified silicones, from the viewpoint of achieving a good balance between compatibility with thermosetting compounds, low thermal expansion, and chemical resistance. In this case, the two or more types of epoxy-modified silicones preferably have different epoxy equivalents, more preferably an epoxy-modified silicone having an epoxy equivalent of 50 to 350 g / mol and an epoxy-modified silicone having an epoxy equivalent of 400 to 4000 g / mol, and even more preferably an epoxy-modified silicone having an epoxy equivalent of 140 to 250 g / mol and an epoxy-modified silicone having an epoxy equivalent of 450 to 3000 g / mol.

[0110] When the epoxy-modified silicone contains two or more types of epoxy-modified silicone, the average epoxy equivalent of the epoxy-modified silicone is preferably 140 to 3000 g / mol, more preferably 250 to 2000 g / mol, and even more preferably 300 to 1000 g / mol. The average epoxy equivalent is calculated using the following formula:

number

[0111] The epoxy-modified silicone preferably contains the epoxy-modified silicone represented by formula (1), from the viewpoint of achieving a good balance between compatibility with thermosetting compounds, low thermal expansion, and chemical resistance. [ka] (In formula (1), R 1 each independently represents an alkylene group, a phenylene group, or an aralkylene group; R 2 each independently represents an alkyl group having 1 to 10 carbon atoms or a phenyl group, and n represents an integer of 1 or more.

[0112] In formula (1), R 1 each independently represents an alkylene group, a phenylene group, or an aralkylene group. 1 The alkylene group represented by the formula (I) may be linear, branched, or cyclic. The number of carbon atoms in the alkylene group is preferably 1 to 12, and more preferably 1 to 4. The alkylene group is not particularly limited, but examples thereof include a methylene group, an ethylene group, and a propylene group.

[0113] In formula (1), R 1 The number of carbon atoms in the aralkylene group represented by formula (XI) is preferably 7 to 30, and more preferably 7 to 13. The aralkylene group is not particularly limited, but examples thereof include groups represented by formula (XI). Formula (XI) [ka] (In formula (XI), * represents a bond.)

[0114] In formula (1), R 1The group represented by the formula (I) may further have a substituent, and examples of the substituent include a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group having 3 to 10 carbon atoms, a cyclic alkyl group having 3 to 10 carbon atoms, a linear alkoxy group having 1 to 10 carbon atoms, a branched alkoxy group having 3 to 10 carbon atoms, and a cyclic alkoxy group having 3 to 10 carbon atoms. Among these, R 1 is particularly preferably a propylene group.

[0115] In formula (1), R 2 each independently represents an alkyl group having 1 to 10 carbon atoms or a phenyl group. The alkyl group and phenyl group may have a substituent. The alkyl group having 1 to 10 carbon atoms may be linear, branched, or cyclic. The alkyl group is not particularly limited, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an isopropyl group, an isobutyl group, and a cyclohexyl group. Among these, R 2 is preferably a methyl group or a phenyl group.

[0116] In formula (1), n ​​represents an integer of 1 or more, for example, 1 to 100. From the viewpoint of further improving compatibility with thermosetting compounds, low thermal expansion properties, and chemical resistance in a well-balanced manner, n is preferably 50 or less, more preferably 30 or less, and even more preferably 20 or less.

[0117] From the viewpoint of further improving compatibility with thermosetting compounds, low thermal expansion, and chemical resistance in a well-balanced manner, the epoxy-modified silicone preferably contains two or more types of epoxy-modified silicones represented by formula (1). In this case, the two or more types of epoxy-modified silicones preferably have different n values, and more preferably contain an epoxy-modified silicone in formula (1) where n is 1 to 2 and an epoxy-modified silicone in formula (1) where n is 5 to 20.

[0118] The average number of epoxy groups per molecule of the epoxy-modified silicone is preferably 1 or more and less than 3, and more preferably 1.5 or more and 2.5 or less. The average number of epoxy groups is calculated by the following formula.

number

[0119] The epoxy-modified silicone may be an epoxy-modified silicone containing a structural unit derived from an alkenylphenol, a structural unit derived from the epoxy-modified silicone, and a structural unit derived from an epoxy compound other than the epoxy-modified silicone (hereinafter, may be referred to as "epoxy-modified silicone (X1)"). The epoxy-modified silicone (X1) may further contain a structural unit derived from a phenolic compound other than alkenylphenol, as necessary.

[0120] Preferred examples of alkenylphenols constituting the alkenylphenol-derived structural units include the (meth)allylphenol compounds described above in the section <<(meth)allyl compounds>>. Preferred examples of phenol compounds that constitute structural units derived from phenol compounds other than structural units derived from alkenylphenols include the phenol compounds described above in the section <<Phenol Compounds>>.

[0121] The content of the alkenylphenol-derived structural unit is preferably 5 to 50 mass%, more preferably 10 to 45 mass%, and even more preferably 10 to 40 mass%, relative to the total mass of the epoxy-modified silicone (X1). When the content of this structural unit is within the above range, even better compatibility with other thermosetting compounds tends to be achieved.

[0122] The content of the structural unit derived from the epoxy-modified silicone is preferably 20 to 60 mass %, more preferably 25 to 55 mass %, and even more preferably 30 to 50 mass %, relative to the total mass of the epoxy-modified silicone (X1). When the content of this structural unit is within the above range, the first insulating resin layer tends to exhibit even better balance between low thermal expansion and chemical resistance.

[0123] The constituent units derived from the epoxy-modified silicone are preferably constituent units derived from an epoxy-modified silicone having an epoxy equivalent of 50 to 350 g / mol (hereinafter also referred to as "low equivalent weight epoxy-modified silicone") and an epoxy-modified silicone having an epoxy equivalent of 400 to 4000 g / mol (hereinafter also referred to as "high equivalent weight epoxy-modified silicone").

[0124] The content of structural units derived from the low equivalent weight epoxy-modified silicone is preferably 5 to 25 mass %, more preferably 7.5 to 20 mass %, and even more preferably 10 to 17 mass %, relative to the total mass of the epoxy-modified silicone (X1).

[0125] The content of structural units derived from the high equivalent weight epoxy-modified silicone is preferably 15 to 55 mass %, more preferably 20 to 52.5 mass %, and even more preferably 25 to 50 mass %, relative to the total mass of the epoxy-modified silicone (X1).

[0126] Regarding epoxy-modified silicones, in addition to the above, the descriptions in paragraphs 0031 to 0044 and 0069 to 0088 of WO 2020 / 022084 and the descriptions in paragraphs 0128 to 0232 of WO 2023 / 013709 can be referred to, the contents of which are incorporated herein by reference.

[0127] <<<Amino-modified silicone>>> A second embodiment of the silicone-modified thermosetting compound is a compound having a structural unit derived from an amino-modified silicone and a structural unit derived from a maleimide compound (hereinafter, sometimes referred to as "amino-modified silicone"). The amino-modified silicone is preferably a polymer obtained by polymerizing an amino-modified silicone, a maleimide compound, and a carboxylic acid and / or a carboxylic acid anhydride. The amino-modified silicone will be described below.

[0128] In this specification, "structural units derived from amino-modified silicone" and "structural units derived from maleimide compounds" refer to structural units obtained by polymerizing the amino-modified silicone and maleimide compound components in the amino-modified silicone, as well as structural units formed by reactions that can give similar structural units. Hereinafter, in this specification, "structural units derived from ..." will be interpreted in the same way.

[0129] The content of structural units derived from amino-modified silicone is preferably 5 to 70 mass %, more preferably 10 to 50 mass %, and even more preferably 15 to 45 mass %, relative to 100 mass % of all structural units in the amino-modified silicone.

[0130] The content of the structural units derived from the maleimide compound is preferably 30 to 95 mass%, more preferably 50 to 90 mass%, and even more preferably 55 to 85 mass%, relative to 100 mass% of all structural units in the amino-modified silicone.

[0131] The amine value of the amino-modified silicone is preferably 2.0 mgKOH / g or less, more preferably 1.0 mgKOH / g or less, and even more preferably 0.5 mgKOH / g or less. The amine value is the total amount of primary amines and secondary amines. When the amine value is 2.0 mgKOH / g or less, an increase in viscosity of the resin composition (1), an increase in molecular weight, gelation of the varnish, and an increase in prepreg viscosity tend to be suppressed. Furthermore, the smaller the amine value, the more likely it is that an increase in viscosity of the resin composition (1), an increase in molecular weight, etc., can be suppressed. The lower limit of the amine value is preferably 0 mgKOH / g. The amine value is measured by a method in accordance with JIS K 7237:1995.

[0132] The weight-average molecular weight (Mw) of the amino-modified silicone is preferably 5,000 to 20,000, and more preferably 10,000 to 15,000. A weight-average molecular weight of 5,000 or more tends to reduce the thermal expansion coefficient of the prepreg, while a weight-average molecular weight of 20,000 or less tends to suppress increases in viscosity and molecular weight of the resin composition (1), varnish gelation, and prepreg viscosity. The weight-average molecular weight of the amino-modified silicone can be adjusted to 5,000 to 20,000 by controlling the reaction conditions, such as temperature and time, during preparation of the amino-modified silicone. In this embodiment, the weight-average molecular weight can be measured by gel permeation chromatography (GPC) and calculated using a standard polystyrene calibration curve.

[0133] From the viewpoint of improving the reactivity between the components constituting the amino-modified silicone and the compatibility with other thermosetting compounds, the amino-modified silicone is preferably a polymer (hereinafter sometimes referred to as "polymer (B1)") obtained by polymerizing at least an amino-modified silicone, a maleimide compound, and a carboxylic acid and / or a carboxylic acid anhydride. The polymer (B1) contains at least a constituent unit derived from the amino-modified silicone and a constituent unit derived from the maleimide compound. For the maleimide compound, the matters described in "Maleimide compound" which may be contained in the resin composition (1) can be taken into consideration, and the preferred ranges are also the same.

[0134] The amino-modified silicone is not particularly limited as long as it is a silicone having one or more amino groups in the molecule, but it is preferably a silicone having two or more amino groups in the molecule, and more preferably contains an amino-modified silicone represented by formula (1). By containing a structural unit derived from the amino-modified silicone, the amino-modified silicone or polymer (B1) can exhibit excellent compatibility with other thermosetting compounds. The amino-modified silicones can be used alone or in appropriate combination of two or more.

[0135] [ka]

[0136] In formula (1), R a R each independently represents a hydrogen atom, an alkyl group, or a phenyl group. b each independently represents a single bond, an alkylene group, or an arylene group, and n represents an integer of 1 to 100.

[0137] Examples of the alkyl group include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl groups; and branched alkyl groups such as isopropyl, isobutyl, and tert-butyl groups. Among these, a methyl group is preferred.

[0138] R b is preferably an alkylene group. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, and a tetramethylene group. The alkylene group preferably has 1 to 4 carbon atoms in the main chain, and is more preferably a trimethylene group.

[0139] Examples of arylene groups include phenyl, naphthyl, indenyl, biphenyl, and anthryl groups.

[0140] The amino group equivalent of the amino-modified silicone is preferably 130 to 6000 g / mol, more preferably 500 to 3000 g / mol, and even more preferably 600 to 2500 g / mol. The amino group equivalent is measured by a method in accordance with JIS K 7237:1995.

[0141] The amino-modified silicone may be a commercially available product, or a product produced by a known method. Commercially available amino-modified silicones include "X-22-161A" (amino group equivalent: 800 g / mol), "X-22-161B" (amino group equivalent: 1500 g / mol), and "KF-8010" (amino group equivalent: 430 g / mol), all manufactured by Shin-Etsu Chemical Co., Ltd.

[0142] The carboxylic acid used in the production of the polymer (B1) is not particularly limited, but is preferably at least one selected from the group consisting of maleic acid, phthalic acid, succinic acid, acetic acid, and propionic acid, more preferably at least one selected from the group consisting of maleic acid, phthalic acid, succinic acid, and acetic acid, and even more preferably at least one selected from the group consisting of maleic acid, phthalic acid, and succinic acid. The carboxylic acid anhydride is not particularly limited, but is preferably at least one selected from the group consisting of maleic anhydride, phthalic anhydride, succinic anhydride, acetic anhydride, and propionic anhydride, more preferably at least one selected from the group consisting of maleic anhydride, phthalic anhydride, succinic anhydride, and acetic anhydride, and even more preferably at least one selected from the group consisting of maleic anhydride, phthalic anhydride, and succinic anhydride.

[0143] Among these, a monocarboxylic acid and / or a monocarboxylic anhydride, or a dicarboxylic acid and / or a dicarboxylic anhydride is preferred, and a dicarboxylic acid and / or a dicarboxylic anhydride is more preferred. When the carboxylic acid and / or the carboxylic anhydride is a dicarboxylic acid and / or a dicarboxylic anhydride, respectively, the effects of the present embodiment tend to be more effectively improved compared to when a monocarboxylic acid and / or a monocarboxylic anhydride is used.

[0144] The carboxylic acids and carboxylic anhydrides may be used singly or in appropriate combination of two or more. The carboxylic acids and carboxylic anhydrides may be used singly or in combination.

[0145] In this embodiment, using only a carboxylic acid anhydride is preferable compared to using only a carboxylic acid. Because carboxylic acid anhydrides have superior reactivity, they tend to be able to favorably suppress the reactivity of the polymer (B1) by reacting with the amino groups in the polymer (B1). As a result, the storage stability of the resin composition (1) and prepreg containing the polymer (B1) is excellent (for example, suppression of an increase in the viscosity of the resin composition (1), an increase in molecular weight, gelation of the varnish, and an increase in the viscosity of the prepreg, etc.), and they also tend to have excellent moldability when mixed with other thermosetting compounds.

[0146] The content of structural units derived from amino-modified silicone in polymer (B1) is preferably 15 to 60 mass%, more preferably 20 to 55 mass%, and even more preferably 30 to 50 mass%, relative to 100 mass% of all structural units in polymer (B1).

[0147] The content of the structural units derived from the maleimide compound in the polymer (B1) is preferably 35 to 75 mass%, more preferably 40 to 70 mass%, and even more preferably 44 to 65 mass%, relative to 100 mass% of all structural units in the polymer (B1).

[0148] In the polymer (B1), the content (total content) of the structural units derived from carboxylic acids and / or carboxylic anhydrides is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and still more preferably 1 to 6% by mass with respect to 100% by mass of all the structural units in the polymer (B1).

[0149] Regarding the epoxy-modified silicone, in addition to the above, the descriptions in paragraphs 0075 to 0127 of International Publication No. 2023 / 013709 can be taken into consideration, and this content is incorporated herein.

[0150] <<BT resin>> The BT resin is obtained by polymerizing a cyanate ester compound and a maleimide compound. When polymerizing, it may be carried out without a solvent, or it may be dissolved in a solvent (such as methyl ethyl ketone, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, toluene, and xylene) and heated and mixed.

[0151] The cyanate ester compound used for synthesizing the BT resin is not particularly limited, and the cyanate ester compounds described in the section of <<cyanate ester compound>> above are preferred.

[0152] The maleimide compound used for synthesizing the BT resin is not particularly limited, and the maleimide compounds described in the section of <<maleimide compound>> above are preferred.

[0153] The ratio of the cyanate ester compound in the BT resin is not particularly limited, but a range of 25 to 95% by mass is preferred, and a range of 30 to 90% by mass is more preferred with respect to the total amount of the BT resin. The ratio of the maleimide compound in the BT resin is not particularly limited, but from the viewpoints of the glass transition temperature, flame retardancy, and curability of the first insulating resin layer, a range of 5 to 75% by mass is preferred, and a range of 10 to 70% by mass is more preferred with respect to the total amount of the BT resin. Also, the BT resin is usually a prepolymer, and its number average molecular weight is preferably in the range of 100 to 100,000.

[0154] In addition to the above, the description of BT resins can be found in paragraphs 0055 to 0057 of Japanese Patent No. 6414799, the contents of which are incorporated herein by reference.

[0155] When the resin composition (1) contains a BT resin, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content, and is preferably 90 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. The resin composition (1) may contain only one type of BT resin, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0156] <<Filling material>> The resin composition (1) preferably contains a filler, which can further improve the physical properties of the resin composition (1) and its cured product, such as dielectric properties (low dielectric constant, low dielectric loss tangent, etc.), flame resistance, and low thermal expansion. Furthermore, the filler used in this embodiment preferably has excellent low dielectric properties. For example, the filler used in this embodiment preferably has a relative dielectric constant (Dk) of 8.0 or less, more preferably 6.0 or less, and even more preferably 4.0 or less, at a frequency of 10 GHz, measured according to the cavity resonator perturbation method. Furthermore, a practical lower limit for the relative dielectric constant is, for example, 2.0 or more. Furthermore, the filler used in this embodiment preferably has a dielectric loss tangent (Df) of 0.05 or less, more preferably 0.01 or less, at a frequency of 10 GHz, measured according to the cavity resonator perturbation method. Furthermore, a practical lower limit for the dielectric loss tangent is, for example, 0.0001 or more.

[0157] The filler used in this embodiment is not particularly limited in type, and can be suitably used by those skilled in the art.Specifically, natural silica, fused silica, synthetic silica, amorphous silica, aerosil, hollow silica, etc. silica, alumina, white carbon, titanium white, titanium oxide, zinc oxide, magnesium oxide, zirconium oxide, etc. metal oxide, zinc borate, zinc stannate, forsterite, barium titanate, strontium titanate, calcium titanate, etc. composite oxide, boron nitride, aggregated boron nitride, silicon nitride, aluminum nitride, etc. nitride, aluminum hydroxide, aluminum hydroxide heat treatment product (aluminum hydroxide is heat treated, and part of crystal water is reduced), boehmite, magnesium hydroxide, etc. metal hydroxide (including hydrate), molybdenum oxide, Examples of fillers include inorganic fillers such as molybdenum compounds such as zinc molybdate, barium sulfate, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, NER-glass, C-glass, L-glass, D-glass, S-glass, M-glass G20, short glass fibers (including fine glass powders such as E-glass, T-glass, D-glass, S-glass, and Q-glass), hollow glass, and spherical glass, as well as organic fillers such as styrene-type, butadiene-type, and acrylic-type rubber powders, core-shell-type rubber powders, silicone resin powders, silicone rubber powders, and silicone composite powders. In this embodiment, the filler preferably contains an inorganic filler, more preferably one or more selected from the group consisting of silica, aluminum hydroxide, aluminum nitride, boron nitride, forsterite, titanium oxide, barium titanate, strontium titanate, and calcium titanate, and from the viewpoint of low dielectric properties, more preferably one or more selected from the group consisting of silica and aluminum hydroxide, and even more preferably silica. By containing these inorganic fillers, the properties of the cured product of the first insulating resin layer, such as heat resistance, dielectric properties, thermal expansion properties, dimensional stability, and flame retardancy, are further improved.

[0158] The content of the filler in the resin composition (1) can be appropriately set depending on the desired properties and is not particularly limited. However, it is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition (1). By setting the content of the filler to the above-mentioned lower limit or more, the heat resistance, low thermal expansion, and dielectric loss tangent of the first insulating resin layer tend to be further improved. Furthermore, the upper limit of the content of the filler is preferably 1,000 parts by mass or less, more preferably 500 parts by mass or less, even more preferably 300 parts by mass or less, even more preferably 250 parts by mass or less, and may be 200 parts by mass or less, or 120 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition (1). By setting the content of the filler to the above-mentioned upper limit or less, the moldability of the first insulating resin layer tends to be further improved. In the resin composition (1), one preferred embodiment is one in which the content of the filler is 30% by mass to 90% by mass of the components excluding the solvent. The resin composition (1) may contain only one type of filler or may contain two or more types of fillers. When two or more types are contained, the total amount is preferably in the above range.

[0159] When a filler, particularly an inorganic filler, is used in the resin composition (1), the resin composition may further contain a silane coupling agent, which tends to improve the dispersibility of the filler and the adhesive strength between the resin component and the filler and the substrate described below. The silane coupling agent is not particularly limited, and examples thereof include silane coupling agents generally used for the surface treatment of inorganic materials, such as aminosilane compounds (e.g., γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, etc.), epoxysilane compounds (e.g., γ-glycidoxypropyltrimethoxysilane, etc.), vinylsilane compounds (e.g., vinyltrimethoxysilane, etc.), styrylsilane compounds (e.g., p-styryltrimethoxysilane, etc.), acrylicsilane compounds (e.g., γ-acryloxypropyltrimethoxysilane, etc.), cationic silane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), phenylsilane compounds (e.g., phenyltrimethoxysilane, etc.). Silane coupling agents can be used alone or in combination of two or more. The content of the silane coupling agent is not particularly limited, but is preferably 0.1 to 10 parts by mass per 100 parts by mass of the resin solid content in the resin composition (1).

[0160] <<Flame retardants>> The resin composition (1) may contain a flame retardant. Examples of the flame retardant include phosphorus-based flame retardants, halogen-based flame retardants, inorganic flame retardants, and silicone-based flame retardants, and phosphorus-based flame retardants are preferred. As the flame retardant, known ones can be used, for example, halogen-based flame retardants such as brominated epoxy resin, brominated polycarbonate, brominated polystyrene, brominated styrene, brominated phthalimide, tetrabromobisphenol A, pentabromobenzyl (meth)acrylate, pentabromotoluene, tribromophenol, hexabromobenzene, decabromodiphenyl ether, bis-1,2-pentabromophenylethane, chlorinated polystyrene, and chlorinated paraffin, red phosphorus, tricresyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate, trixylenyl phosphate, and the like. Examples of flame retardants include phosphorus-based flame retardants such as phosphate, trialkyl phosphate, dialkyl phosphate, tris(chloroethyl)phosphate, phosphazene, 1,3-phenylenebis(phenyl phosphate), 1,3-phenylenebis(2,6-dixylenyl phosphate), and 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide; inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, partial boehmite, boehmite, zinc borate, and antimony trioxide; and silicone-based flame retardants such as silicone rubber and silicone resin. In this embodiment, among these, 1,3-phenylenebis(2,6-dixylenyl phosphate) is preferred because it does not impair the low dielectric properties (Dk and / or Df).

[0161] When the resin composition (1) contains a flame retardant, the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition (1), and may be 12 parts by mass or more depending on the intended use, etc. The lower limit of the content of the flame retardant is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition, and may be 20 parts by mass or less, or 15 parts by mass or less, depending on the intended use, etc. The flame retardants can be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0162] <<Activated ester compounds>> The resin composition (1) may contain an active ester compound. The active ester compound is not particularly limited, and for example, the description in paragraphs 0064 to 0066 of WO 2021 / 172317 can be referred to, the contents of which are incorporated herein by reference.

[0163] When the resin composition (1) contains an active ester compound, the amount thereof is preferably 1 part by mass or more and 50 parts by mass or less per 100 parts by mass of the resin solid content in the resin composition (1). The resin composition (1) in the present embodiment may contain only one type of active ester compound, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range. The resin composition (1) in this embodiment may be configured to be substantially free of an active ester compound. "Substantially free" means that the content of the active ester compound is less than 1 part by mass, preferably less than 0.1 part by mass, and more preferably less than 0.01 part by mass, per 100 parts by mass of the resin solid content in the resin composition (1).

[0164] <<Dispersant>> The resin composition (1) may contain a dispersant. Dispersants commonly used in paints can be used, and the type is not particularly limited. The dispersant is preferably a copolymer-based wetting dispersant, and specific examples include DISPERBYK (registered trademark)-110, 111, 161, 180, 2009, 2152, 2155, BYK (registered trademark)-W996, W9010, W903, and W940, all manufactured by BYK Japan Co., Ltd.

[0165] When the resin composition (1) contains a dispersant, the lower limit of the content thereof is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and may be 0.3 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition (1). The upper limit of the content of the dispersant is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition (1). The dispersant may be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0166] <<Curing accelerator>> The resin composition (1) may further contain a curing accelerator. The curing accelerator is not particularly limited, and examples thereof include imidazoles such as 2-ethyl-4-methylimidazole and triphenylimidazole; organic peroxides such as benzoyl peroxide, bis(1-methyl-1-phenylethyl)peroxide, di-t-butyl peroxide, lauroyl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, di-tert-butyl-di-perphthalate, α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3; azo compounds such as azobisnitriles (e.g., azobisisobutyronitrile); N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2-N-ethylanilinoethanol, and thiazolinone. tertiary amines such as tri-n-butylamine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine, tetramethylbutanediamine, and N-methylpiperidine; phenols such as phenol, xylenol, cresol, resorcinol, and catechol; high-temperature decomposition type radical generators such as 2,3-dimethyl-2,3-diphenylbutane; organic metal salts such as lead naphthenate, lead stearate, zinc naphthenate, zinc octylate, manganese octylate, tin oleate, dibutyltin maleate, manganese naphthenate, cobalt naphthenate, and iron acetylacetonate; compounds obtained by dissolving these organic metal salts in hydroxyl group-containing compounds such as phenol and bisphenol; inorganic metal salts such as tin chloride, zinc chloride, and aluminum chloride; and organic tin compounds such as dioctyltin oxide, other alkyltins, and alkyltin oxides. The curing accelerator is preferably one or more selected from the group consisting of imidazoles, organic peroxides, and organic metal salts, and more preferably a combination of both an imidazole and an organic metal salt, or an imidazole and an organic peroxide.

[0167] When the resin composition (1) contains a curing accelerator, the lower limit of the content thereof is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition (1). The upper limit of the content of the curing accelerator is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, even more preferably 2 parts by mass or less, even more preferably 1.5 parts by mass or less, and may be 1.0 parts by mass or less, 0.8 parts by mass or less, or 0.7 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition (1). The curing accelerators can be used alone or in combination of two or more. When two or more types are used, the total amount falls within the above range.

[0168] <<Solvent>> The resin composition (1) may contain a solvent, preferably an organic solvent. When a solvent is contained, the resin composition (1) is in a form (solution or varnish) in which at least a portion, preferably all, of the various resin solid components described above are dissolved or compatible in the solvent. The solvent is not particularly limited as long as it is a polar or non-polar organic solvent that can dissolve or compatible at least a portion, preferably all, of the various resin solid components described above. Examples of polar organic solvents include ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), cellosolves (e.g., propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, etc.), esters (e.g., ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, isoamyl acetate, ethyl lactate, methyl methoxypropionate, methyl hydroxyisobutyrate, etc.), and amides (e.g., dimethoxyacetamide, dimethylformamide, etc.). Examples of non-polar organic solvents include aromatic hydrocarbons (e.g., toluene, xylene, etc.). The solvents can be used alone or in combination of two or more.

[0169] <<Other resin additive ingredients>> In addition to the above components, the resin composition (1) may contain various polymeric compounds such as elastomers, styrene oligomers, and thermoplastic resin oligomers, as well as various additives. Examples of additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, colorants (dyes and pigments), thickeners, flow control agents, lubricants, antifoaming agents, leveling agents, gloss agents, and polymerization inhibitors such as quinones, phenols, nitrosoamines, and hydroxyamines. These additives may be used alone or in combination of two or more.

[0170] <Fiber base material> The first insulating resin layer preferably further contains a fibrous base material. The fiber base material is a base material formed from fibers, and is preferably a material that serves as the base material (prepreg base material) of the first insulating resin layer, and is preferably glass cloth. The glass cloth is preferably a substrate formed from glass fibers (for example, E-glass, D-glass, L-glass, S-glass, T-glass, Q-glass, UN-glass, NE-glass, NER-glass). The form of the fiber substrate is not particularly limited, and examples thereof include woven fabric, nonwoven fabric, roving, chopped strand mat, surfacing mat, etc. These fiber substrates may be used alone or in combination of two or more. Among these fiber substrates, from the viewpoint of dimensional stability, woven fabrics that have been subjected to an ultra-opening treatment and a clogging treatment are preferred. From the viewpoint of strength and low water absorbency, the fiber substrate should have a thickness of 200 μm or less and a mass of 250 g / m 2 The following glass woven fabrics are preferred, and from the viewpoint of moisture absorption and heat resistance, glass woven fabrics that have been surface-treated with epoxy silane, amino silane, etc. are preferred. From the viewpoint of electrical properties, low-dielectric glass cloths made of glass fibers that exhibit a low relative dielectric constant and a low dielectric loss tangent, such as L-glass, NE-glass, NER-glass, and Q-glass, are more preferred. An example of a fiber substrate with a low relative dielectric constant is one with a relative dielectric constant of 5.0 or less (preferably 3.0 to 4.9). An example of a fiber substrate with a low dielectric loss tangent is one with a dielectric loss tangent of 0.006 or less (preferably 0.001 to 0.005). The relative dielectric constant and dielectric loss tangent are values ​​measured at a frequency of 10 GHz using a perturbation method cavity resonator. In addition, in this embodiment, fiber substrates such as inorganic fibers other than glass (e.g., quartz, etc.) and organic fibers (e.g., polyimide, polyamide, polyester, liquid crystal polyester, polytetrafluoroethylene, etc.) can also be used depending on the application.

[0171] <Metal wiring> In this embodiment, the first insulating resin layer has metal wiring on its surface, which allows the substrate to be used as an internal wiring circuit board. The metal wiring is preferably copper wiring. The metal wiring can be formed by a known method such as a subtractive method or a (semi)additive method.

[0172] <Second insulating resin layer> In this embodiment, the second insulating resin layer is provided on the surface of the first insulating resin layer and covers the metal wiring provided on the surface of the first insulating resin layer. The second insulating resin layer is not particularly specified as long as the dielectric loss tangent of the second insulating resin layer at a frequency of 10 GHz measured by a perturbation method cavity resonator is lower than the dielectric loss tangent of the second insulating resin layer. The second insulating resin layer is usually a layer formed from a resin composition (2) containing a thermosetting compound. In addition, it is usually preferable that the second insulating resin layer does not contain a fibrous base material. The layer formed from the resin composition (2) may be in an uncured, semi-cured, or cured state of the resin solid content contained in the resin composition (2), preferably in a semi-cured or cured state of the resin solid content contained in the resin composition (2).

[0173] The type and other aspects of the thermosetting compound contained in the resin composition (2) are not particularly limited, but it is preferable that the thermosetting compound contains at least one selected from the group consisting of maleimide compounds, cyanate ester compounds, polyphenylene ether compounds having a terminal carbon-carbon unsaturated double bond, polymers having a structural unit represented by formula (V), (meth)allyl compounds, (meth)acrylate compounds, compounds having an indane skeleton having a terminal carbon-carbon unsaturated double bond, epoxy compounds, phenol compounds, oxetane resins, benzoxazine compounds, arylcyclobutene compounds, perfluorovinyl ether resins, polyamide compounds, polyimide compounds, and compounds having a vinylene group. [ka] (In formula (V), Ar represents an aromatic hydrocarbon linking group. * represents a bonding position.)

[0174] <<Maleimide compounds>> The resin composition (2) may contain a maleimide compound. The resin composition (2) is not particularly limited as long as it is a compound having one or more (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and still more preferably 2) maleimide groups in one molecule, and a wide variety of compounds commonly used in the field of printed wiring boards can be used. In this embodiment, the maleimide compound preferably includes one or more selected from the group consisting of a compound represented by formula (M0), a compound represented by formula (M1), a compound represented by formula (M2), a compound represented by formula (M3), a compound represented by formula (M4), a compound represented by formula (M5), a maleimide compound (M6), a maleimide compound (M7), and a maleimide compound (M8), and the compound represented by formula (M0), a compound represented by formula (M1), a compound represented by formula (M2), a compound represented by formula (M3), a compound represented by formula (M4), and a compound represented by formula (M5) The maleimide compound preferably contains one or more compounds selected from the group consisting of compounds represented by formula (M0), compounds represented by formula (M1), compounds represented by formula (M3), compounds represented by formula (M4), and compounds represented by formula (M5), more preferably contains one or more compounds selected from the group consisting of compounds represented by formula (M1), compounds represented by formula (M3), and compounds represented by formula (M5), and even more preferably contains a compound represented by formula (M1) and / or a compound represented by formula (M3). When these maleimide compounds are used in materials for printed wiring boards (e.g., metal foil-clad laminates), they can impart excellent heat resistance.

[0175] [ka] (In formula (M0), R 51 each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R 52 each independently represents a hydrogen atom or a methyl group, and n1 represents an integer of 1 or greater. R 51 are each independently preferably one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. R 52 is preferably a methyl group. n1 is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and even more preferably 1. Specifically, the following compounds are preferred examples of the formula (M0): [ka] In the above formula, R 8 each independently represents a hydrogen atom, a methyl group, or an ethyl group, and is preferably a methyl group.

[0176] The compound represented by formula (M0) may be a single compound or a mixture of two or more compounds. Examples of the mixture include a mixture of compounds with different n1, 51 and / or R 52 Examples of such a mixture include a mixture of compounds having different types of substituents, a mixture of compounds having different bonding positions (meta, para, or ortho positions) of the maleimide group and oxygen atom relative to the benzene ring, and a mixture of compounds having a combination of two or more of the above differences. The same applies to the formulae (M1) to (M7) below.

[0177] [ka] (In formula (M1), R M1 , R M2 , R M3 , and R M4 R each independently represents a hydrogen atom or an organic group. M5 and R M6 Each of Ar independently represents a hydrogen atom or an alkyl group. M represents a divalent aromatic group. A is a 4- to 6-membered alicyclic group. R M7 and R M8 are each independently an alkyl group. mx is 1 or 2, and lx is 0 or 1. R M9 and R M10 R each independently represents a hydrogen atom or an alkyl group. M11 , R M12 , R M13 , and RM14 R each independently represents a hydrogen atom or an organic group. M15 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. px represents an integer of 0 to 3. nx represents an integer of 1 to 20.

[0178] R in the formula M1 , R M2 , R M3 , and R M4 R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. M1 and R M3 are each independently preferably an alkyl group, and R M2 and R M4 is preferably a hydrogen atom. R M5 and R M6 are each independently a hydrogen atom or an alkyl group, preferably an alkyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Ar M represents a divalent aromatic group, preferably a phenylene group, a naphthalenediyl group, a phenanthrenediyl group, or an anthracenediyl group, more preferably a phenylene group, and even more preferably an m-phenylene group. M may have a substituent, and the substituent is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. Mis preferably unsubstituted. A is a 4- to 6-membered alicyclic group, and more preferably a 5-membered alicyclic group (preferably a group that forms an indane ring when combined with a benzene ring). M7 and R M8 are each independently an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group. mx is 1 or 2, and is preferably 2. lx is 0 or 1, and is preferably 1. R M9 and R M10 are each independently a hydrogen atom or an alkyl group, more preferably an alkyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R M11 , R M12 , R M13 , and R M14 R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, with a methyl group being particularly preferred. M12 and R M13 are each independently preferably an alkyl group, and R M11 and R M14 is preferably a hydrogen atom. R M15 each independently represents an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group, and is preferably an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. px represents an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and even more preferably 0. nx represents an integer of 1 to 20. nx may be an integer of 10 or less. The resin composition (2) may contain only one or more compounds represented by formula (M1) having different values ​​of nx. When two or more compounds are contained, the average value of nx (average number of repeating units) n in the compounds represented by formula (M1) in the resin composition (2) is preferably 0.92 or more, more preferably 0.95 or more, even more preferably 1.0 or more, and even more preferably 1.1 or more, to provide a low melting point (low softening point), low melt viscosity, and excellent handleability. Furthermore, n is preferably 10.0 or less, more preferably 8.0 or less, even more preferably 7.0 or less, even more preferably 6.0 or less, and may be 5.0 or less. The same applies to formula (M1-1) described below.

[0179] The compound represented by formula (M1) is preferably a compound represented by the following formula (M1-1). [ka] (In formula (M1-1), R M21 , R M22 , R M23 , and R M24 R each independently represents a hydrogen atom or an organic group. M25 and R M26 R each independently represents a hydrogen atom or an alkyl group. M27 , R M28 , R M29 , and R M30 R each independently represents a hydrogen atom or an organic group. M31 and R M32 R each independently represents a hydrogen atom or an alkyl group. M33 , R M34 , R M35 , and R M36 R each independently represents a hydrogen atom or an organic group.M37 , R M38 , and R M39 each independently represents a hydrogen atom or an alkyl group, and nx represents an integer of 1 or more and 20 or less.

[0180] R in the formula M21 , R M22 , R M23 , and R M24 R each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. M21 and R M23 is preferably an alkyl group, and R M22 and R M24 is preferably a hydrogen atom. R M25 and R M26 are each independently a hydrogen atom or an alkyl group, preferably an alkyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R M27 , R M28 , R M29 , and R M30 each independently represents a hydrogen atom or an organic group, preferably a hydrogen atom. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R M31 and R M32 are each independently a hydrogen atom or an alkyl group, preferably an alkyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R M33, R M34 , R M35 , and R M36 each independently represents a hydrogen atom or an organic group. The organic group here is preferably an alkyl group, more preferably an alkyl group having 1 to 12 carbon atoms, even more preferably an alkyl group having 1 to 6 carbon atoms, still more preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. R M33 and R M36 is preferably a hydrogen atom, and R M34 and R M35 is preferably an alkyl group. R M37 , R M38 , and R M39 are each independently a hydrogen atom or an alkyl group, preferably an alkyl group. The alkyl group here is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, further preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and particularly preferably a methyl group. nx represents an integer of 1 or more and 20 or less. nx may be an integer of 10 or less.

[0181] The compound represented by formula (M1-1) is preferably a compound represented by the following formula (M1-2). [ka] (In formula (M1-2), R M21 , R M22 , R M23 , and R M24 R each independently represents a hydrogen atom or an organic group. M25 and R M26 R each independently represents a hydrogen atom or an alkyl group. M27 , R M28 , R M29 , and R M30 R each independently represents a hydrogen atom or an organic group. M31 and R M32 R each independently represents a hydrogen atom or an alkyl group. M33 , R M34 , RM35 , and R M36 R each independently represents a hydrogen atom or an organic group. M37 , R M38 , and R M39 each independently represents a hydrogen atom or an alkyl group, and nx represents an integer of 1 or more and 20 or less.

[0182] In formula (M1-2), R M21 , R M22 , R M23 , R M24 , R M25 , R M26 , R M27 , R M28 , R M29 , R M30 , R M31 , R M32 , R M33 , R M34 , R M35 , R M36 , R M37 , R M38 , R M39 , and nx are R in formula (M1-1), respectively. M21 , R M22 , R M23 , R M24 , R M25 , R M26 , R M27 , R M28 , R M29 , R M30 , R M31 , R M32 , R M33 , R M34 , R M35 , R M36 , R M37 , R M38 , R M39 , and nx, and the preferred ranges are also the same.

[0183] The compound represented by formula (M1-1) is preferably a compound represented by the following formula (M1-3), and more preferably a compound represented by the following formula (M1-4). [ka] (In formula (M1-3), nx represents an integer of 1 or more and 20 or less.) nx may be an integer of 10 or less. [ka] (In formula (M1-4), nx represents an integer of 1 or more and 20 or less.) nx may be an integer of 10 or less.

[0184] The molecular weight of the compound represented by formula (M1) is preferably 500 or more, more preferably 600 or more, and even more preferably 700 or more. By making the molecular weight equal to or greater than the lower limit, the low dielectric properties and low water absorption of the resulting cured product (insulating resin layer) tend to be further improved. Furthermore, the molecular weight of the compound represented by formula (M1) is preferably 10,000 or less, more preferably 9,000 or less, even more preferably 7,000 or less, even more preferably 5,000 or less, and even more preferably 4,000 or less. By making the molecular weight equal to or less than the upper limit, the heat resistance and handleability of the resulting cured product (insulating resin layer) tend to be further improved.

[0185] The compound represented by formula (M1) preferably has a maleimide group equivalent of 50 g / eq. or more, more preferably 100 g / eq. or more, and even more preferably 200 g / eq. or more. The upper limit of the maleimide group equivalent is preferably 2000 g / eq. or less, more preferably 1000 g / eq. or less, and even more preferably 800 g / eq. or less. Here, the maleimide group equivalent represents the mass of the maleimide compound per equivalent of maleimide group. When the maleimide group equivalent of the compound represented by formula (M1) is within the above range, the resulting cured product (insulating resin layer) tends to have further improved low dielectric properties, low water absorption, heat resistance, and handleability.

[0186] The compound represented by formula (M1) preferably has a molecular weight distribution Mw / Mn calculated by gel permeation chromatography (GPC) measurement of 1.0 to 4.0, more preferably 1.1 to 3.8, even more preferably 1.2 to 3.6, and still more preferably 1.3 to 3.4. When the Mw / Mn of the compound represented by formula (M1) is within the above range, the resulting cured product (insulating resin layer) tends to have further improved low dielectric properties, low water absorption, heat resistance, and handleability.

[0187] For other details of the compound represented by formula (M1), please refer to the descriptions in International Publication No. 2020-217679, the contents of which are incorporated herein by reference.

[0188] [ka] (In formula (M2), R 54 each independently represents a hydrogen atom or a methyl group, and n4 represents an integer of 1 or greater. n4 is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and may be 1. The compound represented by formula (M2) may be, and preferably is, a mixture of compounds in which n4 is different, or may be a mixture of compounds in which other moieties are different, as described for the compound represented by formula (M0).

[0189] [ka] (In formula (M3), R 55 each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group, and n5 represents an integer of 1 or more and 10 or less. R 55are each independently preferably one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. n5 is preferably an integer of 1 or more and 5 or less, more preferably an integer of 1 to 3, and even more preferably 1 or 2. The compound represented by formula (M3) may be, and preferably is, a mixture of compounds in which n5 is different, or may be a mixture of compounds in which other moieties are different, as described for the compound represented by formula (M0).

[0190] [ka] (In formula (M4), R 56 each independently represents a hydrogen atom, a methyl group, or an ethyl group; R 57 each independently represents a hydrogen atom or a methyl group. R 56 are preferably each independently a methyl group or an ethyl group, and more preferably a methyl group and an ethyl group on each of the two benzene rings, and R 57 is preferably a methyl group.

[0191] [ka] (In formula (M5), R 58 each independently represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a phenyl group; R 59 each independently represents a hydrogen atom or a methyl group, and n6 represents an integer of 1 or greater. R 58are each independently preferably one selected from the group consisting of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, and a phenyl group, more preferably a hydrogen atom and / or a methyl group, and even more preferably a hydrogen atom. R 59 is preferably a methyl group. n6 is preferably an integer of 1 to 10, more preferably an integer of 1 to 5, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and may be 1. The compound represented by formula (M5) may be, and preferably is, a mixture of compounds in which n6 is different, or may be a mixture of compounds in which other moieties are different, as described for the compound represented by formula (M0).

[0192] The maleimide compound (M6) is a compound having a structural unit represented by formula (M6) and maleimide groups at both ends of the molecular chain. [ka] (In formula (M6), R 61 represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. 62 represents a linear or branched alkylene group having 1 to 16 carbon atoms, or a linear or branched alkenylene group having 2 to 16 carbon atoms. 63 each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms, or a linear or branched alkenyl group having 2 to 16 carbon atoms. Each n independently represents an integer of 0 to 10. For details of the maleimide compound (M6) and its production method, please refer to paragraphs 0061 to 0066 of WO 2020 / 262577, the contents of which are incorporated herein by reference.

[0193] The maleimide compound (M7) is a maleimide compound obtained by reacting, as reaction raw materials (1), an aromatic amine compound (a1) having 1 to 3 alkyl groups on the aromatic ring, an aromatic divinyl compound (a2) having two ethenyl groups, and maleic anhydride. The maleimide compound (M7) is preferably a compound represented by the formula (M7). [ka] (In the above formula (M7), R 1 each independently represents an alkyl group having 1 to 10 carbon atoms, and R 2 each independently represents an alkyl group, alkoxy group, or alkylthio group having 1 to 10 carbon atoms; an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms; a cycloalkyl group having 3 to 10 carbon atoms; a halogen atom; a hydroxyl group; or a mercapto group, R 3 , R 4 , R 5 and R 6 each independently represents a hydrogen atom or a methyl group, and R 3 and R 4 One of the groups is a hydrogen atom and the other is a methyl group, and R 5 and R 6 one of which is a hydrogen atom and the other is a methyl group, X 1 are each independently represented by the following formula (x): [ka] (In formula (x), R 7 and R 8 each independently represents a hydrogen atom or a methyl group, and R 7 and R 8 One of the groups is a hydrogen atom and the other is a methyl group, and R 9 each independently represents an alkyl group, alkoxy group, or alkylthio group having 1 to 10 carbon atoms; an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms; a cycloalkyl group having 3 to 10 carbon atoms; a halogen atom; a hydroxyl group; or a mercapto group, and t represents an integer of 0 to 4. and r represents a substituent represented by X 1 X per benzene ring to which 1 is the average number of substitutions, and represents a number from 0 to 4, p represents an integer from 1 to 3, q ​​represents an integer from 0 to 4, and k represents an integer from 1 to 100.

[0194] For details of the maleimide compound (M7) used in this embodiment, refer to the description in Japanese Patent No. 7160151, the contents of which are incorporated herein by reference.

[0195] The maleimide compound (M8) is a maleimide compound having a hydrocarbon group in which eight or more atoms are linearly linked, and is preferably a compound represented by formula (M8): Such bismaleimide compounds (M8) tend to have higher stress relaxation ability, and as a result, the thermal expansion coefficient of the resulting cured product tends to be lower, and the electrical properties such as the dielectric constant and dielectric loss tangent tend to be more excellent. [ka] (In formula (M8), R 1 and R 3 each independently represents a hydrocarbon group having 8 or more atoms linked in a linear chain, and R 2 each independently represents a substituted or unsubstituted cyclic hydrocarbon group having 4 to 10 atoms constituting the ring, which may contain a heteroatom, and n represents a number from 0 to 10.

[0196] In formula (M8), R 1 and R 3 is an octylene group, and R 2 is preferably a cycloalkylene group having an alkyl group having 6 to 8 carbon atoms as a substituent.

[0197] For the maleimide compound (M8), the descriptions in paragraphs 0013 to 0022 of JP 2018-083893 A and paragraphs 0011 to 0022 of JP 2018-090728 A can be referred to, the contents of which are incorporated herein by reference.

[0198] The maleimide compound may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include "BMI-80" manufactured by K.I. Chemical Industry Co., Ltd. as the compound represented by formula (M0), "NE-X-9470S" and "NE-X-9480S" manufactured by DIC Corporation as the compound represented by formula (M1), "BMI-2300" manufactured by Daiwa Chemical Industry Co., Ltd. as the compound represented by formula (M2), "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd. as the compound represented by formula (M3), and "MIR-3000-70MT" manufactured by Nippon Kayaku Co., Ltd. as the compound represented by formula (M4). Examples of compounds that can be used include "BMI-70" manufactured by K.I. Chemical Industry Co., Ltd. and "BMI-5100" manufactured by Daiwa Chemical Industry Co., Ltd.; "MIR-5000" manufactured by Nippon Kayaku Co., Ltd. as a compound represented by formula (M5); "MIZ-001" manufactured by Nippon Kayaku Co., Ltd. as a maleimide compound (M6); "NE-X-9500" manufactured by DIC Corporation as a maleimide compound (M7); and "SFR" manufactured by Resonac Corporation, and "BMI-689," "BMI-3000," and "BMI-5000" manufactured by DESIGNER MOLECULES INC. as a maleimide compound (M8).

[0199] Furthermore, examples of maleimide compounds other than those mentioned above include N-phenylmaleimide, N-cyclohexylmaleimide, phenylmethanemaleimide oligomers, m-phenylenebismaleimide, 4-methyl-1,3-phenylenebismaleimide, 1,6-bismaleimide-(2,2,4-trimethyl)hexane, 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 1,3-bis(3-maleimidophenoxy)benzene, 1,3-bis(4-maleimidophenoxy)benzene, prepolymers thereof, and prepolymers of these maleimides and amines. In addition to the above, the compounds described in paragraphs 0051 to 0068 of International Publication No. 2020 / 262577 can be referred to, the contents of which are incorporated herein by reference.

[0200] When the resin composition (2) contains a maleimide compound, the lower limit of its content is preferably 1 part by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and may even be 20 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, or 60 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition (2). When the content of the maleimide compound is equal to or greater than the above-mentioned lower limit, the heat resistance of the second insulating resin layer tends to be improved. Furthermore, the upper limit of the content of the maleimide compound is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and may even be 70 parts by mass or less, 60 parts by mass or less, or 50 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition (2). When the content of the maleimide compound is equal to or less than the above-mentioned upper limit, the metal foil peel strength and low water absorption of the second insulating resin layer tend to be improved. The resin composition (2) in the present embodiment may contain only one maleimide compound or may contain two or more maleimide compounds. When two or more maleimide compounds are contained, the total amount is preferably in the above range.

[0201] <<Cyanate ester compounds>> The resin composition (2) preferably contains a cyanate ester compound, which further improves the adhesion between the insulating resin layer and the metal foil (plating layer and / or wiring pattern) and the ability to form fine wiring. The cyanate ester compound is not particularly limited as long as it contains one or more (preferably 2 to 12, more preferably 2 to 6, even more preferably 2 to 4, still more preferably 2 or 3, and still more preferably 2) cyanate groups (cyanato groups) in one molecule, and a wide range of compounds commonly used in the field of printed wiring boards can be used. In addition, the cyanate ester compound is preferably a compound in which the cyanate group is directly bonded to an aromatic skeleton (aromatic ring). As the cyanate ester compound, those described in the resin composition (1) can be preferably used, naphthol aralkyl cyanate ester compounds are more preferred, and cyanate ester compounds represented by formula (5) are more preferred.

[0202] When the resin composition (2) contains a cyanate ester compound, the lower limit of its content is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition (2). A cyanate ester compound content of 0.1 parts by mass or more tends to improve the adhesion of the second insulating resin layer to the metal foil (plating layer and / or wiring pattern), fine wiring formability, heat resistance, flame resistance, chemical resistance, low dielectric properties (dielectric constant and / or dielectric dissipation factor), and insulating properties. The upper limit of the cyanate ester compound content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition (2). It may be 8 parts by mass or less, or 6 parts by mass or less, depending on the intended use. The resin composition (2) in the present embodiment may contain only one type of cyanate ester compound, or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0203] <<Polyphenylene ether compound with terminal carbon-carbon unsaturated double bonds>> The resin composition (2) preferably contains a polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond. By containing the polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond in the resin composition (2), the adhesion between the insulating resin layer and the metal foil (plating layer and / or wiring pattern) and the ability to form fine wiring are further improved. The polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond is preferably a polyphenylene ether compound having two or more terminal carbon-carbon unsaturated double bonds, more preferably a polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acryloyl groups, (meth)allyl groups, and vinylbenzyl groups, and even more preferably a polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acryloyl groups and vinylbenzyl groups. The use of these polyphenylene ether compounds tends to further improve the adhesion between the insulating resin layer and the metal foil (plating layer and / or wiring pattern) and the ability to form fine wiring, as well as more effectively improve the low dielectric properties, low water absorption, etc. of printed wiring boards, etc. These will be explained in detail below.

[0204] The polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond is exemplified by a compound having a phenylene ether skeleton represented by the following formula (X1).

[0205] [ka] (In formula (X1), R 24 , R 25 , R 26 , and ,R 27 may be the same or different and represent an alkyl group having 6 or less carbon atoms, an aryl group, a halogen atom, or a hydrogen atom.

[0206] The polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond is represented by the formula (X2): [ka] (In formula (X2), R 28 , R 29 , R 30 , R 34 , and ,R 35 may be the same or different and represent an alkyl group having 6 or less carbon atoms or a phenyl group. 31, R 32 , and ,R 33 may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. and / or a structural unit represented by the formula (X3): [ka] (In formula (X3), R 36 , R 37 , R 38 , R 39 , R 40 , R 41 , R 42 , and ,R 43 may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. -A- is a straight-chain, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0207] The polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond is preferably a modified polyphenylene ether compound in which some or all of the terminals are functionalized with ethylenically unsaturated groups (hereinafter sometimes referred to as "modified polyphenylene ether compound (g)"). A modified polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acryloyl groups, (meth)allyl groups, and vinylbenzyl groups is more preferred, and a modified polyphenylene ether compound having two or more terminal groups selected from the group consisting of (meth)acryloyl groups and vinylbenzyl groups is even more preferred. The use of such modified polyphenylene ether compound (g) not only improves the adhesion between the insulating resin layer and the metal foil (plated layer and / or wiring pattern) and the ability to form fine wiring, but also reduces the dielectric loss tangent (Df) of the cured product of the resin composition (2) and enhances its low water absorption. Modified polyphenylene ether compounds (g) may be used singly or in combination of two or more.

[0208] The modified polyphenylene ether compound (g) includes a polyphenylene ether compound represented by formula (OP). [ka] (In formula (OP), X represents an aromatic group, -(YO) n1 - represents a polyphenylene ether structure, n1 represents an integer of 1 to 100, and n2 represents an integer of 1 to 4. Rx is a group represented by formula (Rx-1) or formula (Rx-2). [ka] (In formula (Rx-1) and formula (Rx-2), R 1 , R 2 , and ,R 3 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. * is a bonding site with an oxygen atom. Each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms. z represents an integer of 0 to 4. r represents an integer of 1 to 6.

[0209] When n1 and / or n2 are integers of 2 or greater, the n1 structural units (YO) and / or n2 structural units may be the same or different. n2 is preferably 2 or greater, and more preferably 2.

[0210] In formula (Rx-1) and formula (Rx-2), R 1 , R 2 , and ,R 3 each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group. R 1 is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. R 2 and R 3 are each independently preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. R 1 , R 2 , and ,R3 The number of carbon atoms in each of the alkyl group, alkenyl group, and alkynyl group is preferably 5 or less, and more preferably 3 or less.

[0211] In formula (Rx-1), r represents an integer of 1 to 6, preferably an integer of 1 to 5, more preferably an integer of 1 to 4, even more preferably an integer of 1 to 3, still more preferably 1 or 2, and even more preferably 1.

[0212] In formula (Rx-1), each Mc independently represents a hydrocarbon group having 1 to 12 carbon atoms, preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 10 carbon atoms, still more preferably a methyl group, ethyl group, isopropyl group, isobutyl group, t-butyl group, pentyl group, octyl group, or nonyl group, and still more preferably a methyl group, ethyl group, isopropyl group, isobutyl group, or t-butyl group. In formula (Rx-1), z represents an integer of 0 to 4, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, still more preferably 0 or 1, and still more preferably 0.

[0213] A specific example of the group represented by formula (Rx-1) is a vinylbenzyl group, and a specific example of the group represented by formula (Rx-2) is a (meth)acryloyl group.

[0214] The modified polyphenylene ether compound (g) is preferably a compound represented by formula (OP-1). [ka] (In formula (OP-1), X represents an aromatic group, -(YO)n2- represents a polyphenylene ether structure, and R 1 , R 2 , and ,R 3each independently represents a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group, n1 represents an integer of 1 to 6, n2 represents an integer of 1 to 100, and n3 represents an integer of 1 to 4. When n2 and / or n3 are integers of 2 or greater, the n2 structural units (YO) and / or n3 structural units may be the same or different. n3 is preferably 2 or greater, and more preferably 2.

[0215] The modified polyphenylene ether compound (g) in this embodiment is preferably a compound represented by formula (OP-2). [ka] where -(OXO)- is a compound of formula (OP-3): [ka] (In formula (OP-3), R 4 , R 5 , R 6 , R 10 , and ,R 11 R may be the same or different and is an alkyl group or a phenyl group having 6 or less carbon atoms. 7 , R 8 , and ,R 9 may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. and / or formula (OP-4): [ka] (In formula (OP-4), R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , and ,R 19 may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms, or a phenyl group. -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.

[0216] Also, -(Y-O)- is represented by formula (OP-5): [Chemical formula] (In formula (OP-5), R 20 and R 21 may be the same or different and are an alkyl group having 6 or less carbon atoms or a phenyl group. R 22 and R 23 may be the same or different and are a hydrogen atom, an alkyl group having 6 or less carbon atoms or a phenyl group.) It is preferably represented by. In particular, R 20 and R 21 are each independently a group having one or more methyl groups and / or cyclohexyl groups, so that the rigidity of the resulting resin molecules increases. Since molecules with high rigidity have lower mobility than molecules with low rigidity, the relaxation time during dielectric relaxation becomes longer, which is preferable because of excellent low dielectric properties (Dk and / or Df). An example of formula (OP-5) is the following structure. [Chemical formula] Regarding the polyphenylene compound having the above structure, the description in JP-A-2019-194312 can be referred to, and this content is incorporated herein.

[0217] In formula (OP-2), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100. It is preferable that a and b are each independently an integer of 0 to 50, more preferably an integer of 1 to 30, and preferably an integer of 1 to 10. When a and / or b is an integer of 2 or more, two or more -(Y-O)- may each independently be an arrangement of one kind of structure, or two or more kinds of structures may be arranged in blocks or randomly. Also, when a plurality of compounds represented by formula (OP-2) are included, the average value of a is preferably 1 < a < 10, and the average value of b is preferably 1 < b < 10.

[0218] Examples of -A- in formula (OP-4) include divalent organic groups such as a methylene group, an ethylidene group, a 1-methylethylidene group, a 1,1-propylidene group, a 1,4-phenylenebis(1-methylethylidene) group, a 1,3-phenylenebis(1-methylethylidene) group, a cyclohexylidene group, a phenylmethylene group, a naphthylmethylene group, and a 1-phenylethylidene group, but are not limited to these.

[0219] Among the compounds represented by the above formula (OP-2), R 4 , R 5 , R 6 , R 10 , R 11 , R 20 , and ,R 21 is an alkyl group having 3 or less carbon atoms, and R 7 , R 8 , R 9 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 22 , and ,R 23 is a hydrogen atom or an alkyl group having 3 or less carbon atoms, and it is particularly preferred that -(OXO)- represented by formula (OP-3) or formula (OP-4) is formula (OP-9), formula (OP-10), and / or formula (OP-11), and -(YO)- represented by formula (OP-5) is formula (OP-12) or formula (OP-13). When a and / or b are integers of 2 or more, the two or more -(YO)- may each independently be a structure in which two or more of formula (OP-12) and / or formula (OP-13) are arranged, or a structure in which formula (OP-12) and formula (OP-13) are arranged in blocks or randomly.

[0220] [ka] [ka] (In formula (OP-10), R 44 , R 45 , R 46 , and ,R 47 may be the same or different and are a hydrogen atom or a methyl group. -B- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms. Specific examples of -B- include the same as the specific examples of -A- in formula (OP-4). [ka] (In formula (OP-11), -B- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or less carbon atoms.) Specific examples of -B- include the same as the specific examples of -A- in formula (OP-4). [ka] [ka]

[0221] The polyphenylene ether compound used in this embodiment is more preferably a compound represented by formula (OP-14) and / or a compound represented by formula (OP-15), and even more preferably a compound represented by formula (OP-15). [ka] (In formula (OP-14), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.) In formula (OP-14), a and b each independently have the same meaning as a and b in formula (OP-2), and the preferred ranges are also the same. [ka] (In formula (OP-15), a and b each independently represent an integer of 0 to 100, and at least one of a and b is an integer of 1 to 100.) In formula (OP-15), a and b each independently have the same meaning as a and b in formula (OP-2), and the preferred ranges are also the same.

[0222] Furthermore, the polyphenylene ether compound used in this embodiment may also be a compound represented by formula (OP-16). [ka] (In formula (OP-16), each x independently represents an integer of 0 to 100, and at least one of the two x's is an integer of 1 to 100.)

[0223] The polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond may be produced by a known method, or a commercially available product may be used. Examples of commercially available products include "SA9000" manufactured by SABIC Innovative Plastics, which is a modified polyphenylene ether compound having a terminal methacryloyl group. Examples of modified polyphenylene ether compounds having a terminal vinylbenzyl group include "OPE-2St1200" and "OPE-2st2200" manufactured by Mitsubishi Gas Chemical Company. Examples of modified polyphenylene ether compounds having a terminal hydroxyl group, such as "SA90" manufactured by SABIC Innovative Plastics, which are modified to a vinylbenzyl group using vinylbenzyl chloride or the like, may also be used as modified polyphenylene ether compounds having a terminal hydroxyl group.

[0224] For details of polyphenylene ether compounds having terminal carbon-carbon unsaturated double bonds, see JP 2006-028111 A, JP 2018-131519 A, WO 2019-138992 A, and WO 2022-054303 A. The contents of these publications are incorporated herein by reference.

[0225] The polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond (preferably a modified polyphenylene ether compound (g)) preferably has a polystyrene-equivalent number average molecular weight (details follow the method described in the Examples below) as measured by GPC (gel permeation chromatography) of 500 or more and 3,000 or less. When the number average molecular weight is 500 or more, stickiness tends to be further suppressed when the resin composition (2) is formed into a coating film. When the number average molecular weight is 3,000 or less, solubility in solvents tends to be further improved. Furthermore, the polystyrene-equivalent weight average molecular weight (GPC) of the polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond (preferably a modified polyphenylene ether compound (g)) (details follow the method described in the Examples below) is preferably 800 to 10,000, more preferably 800 to 5,000. By setting it to be equal to or greater than the lower limit, the relative dielectric constant (Dk) and / or dielectric loss tangent (Df) of the cured product of the resin composition (2) tends to be lower, while by setting it to be equal to or less than the upper limit, the solubility, low viscosity, and moldability of the resin composition (2) in a solvent when preparing a varnish or the like, which will be described later, tend to be further improved. Furthermore, in the case of the modified polyphenylene ether compound (g), the terminal carbon-carbon unsaturated double bond equivalent is preferably 400 to 5000 g, more preferably 400 to 2500 g, per carbon-carbon unsaturated double bond. By setting the equivalent at or above the lower limit, the relative permittivity (Dk) and / or dielectric loss tangent (Df) of the cured product of the resin composition (2) tend to be lower. By setting the equivalent at or below the upper limit, the solubility, low viscosity, and moldability of the resin composition (2) in solvents tend to be improved.

[0226] When the resin composition (2) contains a polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond, the lower limit of its content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, and even more preferably 13 parts by mass or more, per 100 parts by mass of the resin solids in the resin composition (2). By ensuring that the content is equal to or greater than the lower limit, the adhesion between the second insulating resin layer and the metal foil (plating layer and / or wiring pattern) and the ability to form fine wiring are further improved, and low dielectric properties (Dk and / or Df) and moisture absorption heat resistance tend to be more excellent. The upper limit of the content of the polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, still more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and still more preferably 25 parts by mass or less, per 100 parts by mass of the resin solids in resin composition (2). By keeping the content at or below the upper limit, the adhesion, heat resistance, and chemical resistance of the second insulating resin layer and the metal layer (plating layer and / or wiring pattern) tend to be better. The resin composition (2) in this embodiment may contain only one polyphenylene ether compound having a terminal carbon-carbon unsaturated double bond, or may contain two or more polyphenylene ether compounds. When two or more polyphenylene ether compounds are contained, the total amount is preferably within the above range.

[0227] <<Compounds with an indane skeleton containing a terminal carbon-carbon unsaturated double bond>> The resin composition (2) may contain a compound having an indane skeleton with a terminal carbon-carbon unsaturated double bond. An example of a compound having an indane skeleton with a terminal carbon-carbon unsaturated double bond is a resin represented by formula (T). [ka] (In formula (T), R is a group containing a structural unit represented by formula (Tx). R xis a group containing a carbon-carbon unsaturated double bond. y represents a hydrogen atom, a group containing an -O-carbon-carbon unsaturated double bond, or another group. y1 represents an integer of 1 to 4. Mb's each independently represent a hydroxyl group, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may be substituted with a hydroxyl group or a halogen atom. y represents an integer of 0 to 4. [ka] (In formula (Tx), n, o, and p represent the average number of structural units, n is a number greater than 0 and equal to or less than 20, o and p each independently represent a number from 0 to 20, and 1.0≦n+o+p≦20.0. Each Ma independently represents a hydrocarbon group of 1 to 12 carbon atoms which may be substituted with a halogen atom. Each x independently represents an integer from 0 to 4. The structural units (a), (b), and (c) are each bonded to other structural units (a) to (c) via *, and the structural units may be bonded randomly.)

[0228] The compound having an indane skeleton with a terminal carbon-carbon unsaturated double bond may also be a resin whose main component is a structural unit derived from the compound represented by formula (DIP) and has a structure represented by formula (In-1) and / or formula (In-2). [ka] (In formula (DIP), each Ma independently represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom, and x represents an integer of 0 to 4.) [ka] (In formula (In-1), Mb's each independently represent a hydroxyl group, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may be substituted with a hydroxyl group or a halogen atom. y represents an integer of 0 to 3. R x is a group containing a carbon-carbon unsaturated double bond. * is the bonding site to other moieties. [ka] (In formula (In-2), each Ma independently represents a hydrocarbon group having 1 to 12 carbon atoms which may be substituted with a halogen atom; x represents an integer of 0 to 3; each Mb independently represents a hydroxyl group, a halogen atom, or a hydrocarbon group having 1 to 20 carbon atoms which may be substituted with a hydroxyl group or a halogen atom; y represents an integer of 0 to 4; R x is a group containing a carbon-carbon unsaturated double bond. xp is the number of bonds coming out of the benzene ring and is an integer of 1 or 2. * is the bonding site to another moiety.

[0229] For compounds having an indane skeleton having a terminal carbon-carbon unsaturated double bond, see paragraphs 0011 to 0025 of WO 2023 / 176766, paragraphs 0012 to 0033 of WO 2023 / 176764, paragraphs 0012 to 0033 of WO 2023 / 176763, and paragraphs 0026 to 0043 of WO 2023 / 176765, the contents of which are incorporated herein by reference.

[0230] <<Compounds containing vinylene groups>> The resin composition (2) may contain a compound having a vinylene group. Examples of compounds having a vinylene group include compounds containing one or more -CH=CH- in the molecule, and compounds containing one -CH=CH- in the molecule are preferred. Furthermore, compounds having a vinylene group that also fall under the category of maleimide compounds are considered maleimide compounds. Specific examples of the compound having a vinylene group are preferably acenaphthylene and pyracylene, and more preferably acenaphthylene. In this specification, compounds that also correspond to compounds having a vinylene group, such as imidazole compounds described later, but that are explicitly stated as components other than compounds having a vinylene group (for example, curing accelerators) are not considered to be compounds having a vinylene group.

[0231] For details of the polymer having a structural unit represented by formula (V), (meth)allyl compound, (meth)acrylate compound, epoxy compound, phenol compound, oxetane resin, benzoxazine compound, arylcyclobutene compound, perfluorovinyl ether resin, polyamide compound, and polyimide compound, see paragraphs 0075 to 0105 of WO 2023 / 171554 and paragraphs 0198 to 0200 of WO 2023 / 176765, the contents of which are incorporated herein by reference.

[0232] The content of the polymer having a structural unit represented by formula (V) in resin composition (2) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the resin solid content in resin composition (2). Depending on the intended use, it may be 15 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, or 30 parts by mass or more. By setting the content of the polymer having a structural unit represented by formula (V) to the above-mentioned lower limit or more, the low dielectric properties and low water absorption of the second insulating resin layer tend to be further improved. Furthermore, the upper limit of the content of the polymer having a structural unit represented by formula (V) is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of the resin solid content in resin composition (2). Depending on the intended use, it may be 30 parts by mass or less, or 20 parts by mass or less. By setting the content of the thermosetting compound to the above-mentioned upper limit or less, the heat resistance, plating adhesion, low thermal expansion, etc. of the insulating resin layer of the second insulating resin layer tend to be further improved. The resin composition (2) may contain only one polymer having a structural unit represented by formula (V), or may contain two or more polymers. When two or more polymers are contained, the total amount is preferably within the above range.

[0233] The total amount of the thermosetting compounds in the resin composition (2) is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 55 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition (2). By setting the content of the thermosetting compounds at or above the lower limit, the heat resistance and plating adhesion of the second insulating resin layer tend to be further improved. Furthermore, the upper limit of the content of the thermosetting compounds is preferably 99 parts by mass or less, more preferably 90 parts by mass or less, and even more preferably 85 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition (2). Depending on the application, it may be 80 parts by mass or less or 70 parts by mass or less. By setting the content of the thermosetting compounds at or below the upper limit, the low dielectric properties and low water absorption of the second insulating resin layer tend to be further improved. The resin composition (2) may contain only one type of thermosetting compound or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0234] <<Elastomer>> The resin composition (2) may contain an elastomer. In this embodiment, the elastomer is preferably a thermoplastic elastomer. The thermoplastic elastomer in this embodiment is not particularly limited, and examples thereof include at least one selected from the group consisting of polyisoprene, polybutadiene, styrene butadiene, butyl rubber, ethylene propylene rubber, styrene butadiene ethylene, styrene butadiene styrene, styrene isoprene styrene, styrene ethylene butylene styrene, styrene propylene styrene, styrene ethylene propylene styrene, fluororubber, silicone rubber, hydrogenated compounds thereof, alkyl compounds thereof, and copolymers thereof. Further, examples of elastomers include oligomers or polymers having a curable vinyl functional group, and polybutadiene resins described in paragraphs 0044 and 0045 of JP 2019-194312 A, the contents of which are incorporated herein by reference.

[0235] The number-average molecular weight of the elastomer (preferably a thermoplastic elastomer) in this embodiment is preferably 1,000 or more. By setting the number-average molecular weight to 1,000 or more, the low dielectric properties (Dk and / or Df, particularly low dielectric loss tangent) of the resulting cured product (insulating resin layer) tend to be more excellent. The number-average molecular weight is preferably 1,500 or more, more preferably 2,000 or more, and may be 60,000 or more, 70,000 or more, or 80,000 or more depending on the application, etc. The upper limit of the number-average molecular weight of the elastomer (preferably a thermoplastic elastomer) is preferably 400,000 or less, more preferably 350,000 or less, and even more preferably 300,000 or less. Setting the number-average molecular weight below the upper limit tends to improve the solubility of the elastomer component in the resin composition (2). When the resin composition (2) contains two or more elastomers, it is preferable that the number average molecular weight of the mixture thereof falls within the above range.

[0236] The elastomer used in this embodiment may be a resin containing a polybutadiene structure. The polybutadiene structure may be partially or completely hydrogenated. Specific examples include B-1000, B-2000, B-3000, BI-2000, and BI-3000 manufactured by Nippon Soda Co., Ltd., and Ricon 100, Ricon 130, Ricon 131, Ricon 142, Ricon 150, Ricon 181, and Ricon 184 manufactured by Cray Valley.

[0237] The elastomer used in this embodiment may be a resin containing a poly(meth)acrylate structure, such as Teisan Resin manufactured by Nagase ChemteX Corporation, and ME-2000, W-197C, KG-15, and KG-3000 manufactured by Negami Chemical Industrial Co., Ltd.

[0238] The elastomer used in this embodiment may be a resin containing a polycarbonate structure. Resins containing a polycarbonate structure are sometimes referred to as "polycarbonate resins." Examples of such resins include carbonate resins without reactive groups, hydroxyl group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxyl group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, urethane group-containing carbonate resins, and epoxy group-containing carbonate resins. Here, the term "reactive group" refers to a functional group capable of reacting with other components, such as a hydroxy group, a phenolic hydroxyl group, a carboxy group, an acid anhydride group, an isocyanate group, a urethane group, or an epoxy group. Specific examples of polycarbonate resins include FPC0220 and FPC2136 manufactured by Mitsubishi Gas Chemical Company, Inc., and T6002 and T6001 (polycarbonate diol) manufactured by Asahi Kasei Corporation.

[0239] The elastomer used in this embodiment is a resin containing a polysiloxane structure, such as SMP-2006, SMP-2003PGMEA, SMP-5005PGMEA, KR-510, and SMP-7014-3S manufactured by Shin-Etsu Silicones Co., Ltd.

[0240] The elastomer used in this embodiment may be a resin containing a polyalkylene structure and / or a polyalkyleneoxy structure. The polyalkyleneoxy structure is preferably a polyalkyleneoxy structure having 2 to 15 carbon atoms, more preferably a polyalkyleneoxy structure having 3 to 10 carbon atoms, and particularly preferably a polyalkyleneoxy structure having 5 to 6 carbon atoms. Specific examples of resins containing a polyalkylene structure and / or a polyalkyleneoxy structure include PTXG-1000 and PTXG-1800 manufactured by Asahi Kasei Fibers Corporation.

[0241] The elastomer used in this embodiment is a resin containing a polyisoprene structure, and specific examples include KL-610 and KL613 manufactured by Kuraray Co., Ltd.

[0242] The elastomer used in this embodiment is a resin containing a polyisobutylene structure, such as SIBSTAR-073T (styrene-isobutylene-styrene triblock copolymer) and SIBSTAR-042D (styrene-isobutylene diblock copolymer), both manufactured by Kaneka Corporation.

[0243] In this embodiment, the thermoplastic elastomer is preferably a thermoplastic elastomer containing styrene monomer units and conjugated diene monomer units (hereinafter referred to as "thermoplastic elastomer (E)"). By using such a thermoplastic elastomer (E), the low dielectric properties (Dk and / or Df, particularly low dielectric loss tangent) of the resulting cured product (insulating resin layer) are further improved.

[0244] The thermoplastic elastomer (E) in this embodiment contains a styrene monomer unit. By containing a styrene monomer unit, the solubility of the thermoplastic elastomer (E) in the resin composition (2) is improved. Examples of styrene monomers include styrene, α-methylstyrene, p-methylstyrene, divinylbenzene (vinylstyrene), N,N-dimethyl-p-aminoethylstyrene, and N,N-diethyl-p-aminoethylstyrene. Among these, styrene, α-methylstyrene, and p-methylstyrene are preferred from the viewpoints of availability and productivity. Among these, styrene is particularly preferred. The content of styrene monomer units in the thermoplastic elastomer (E) is preferably in the range of 10 to 50% by mass of all monomer units, more preferably in the range of 13 to 45% by mass, and even more preferably in the range of 15 to 40% by mass. If the content of styrene monomer units is 50% by mass or less, the adhesion and tackiness to fiber substrates and the like will be better. Furthermore, if the content is 10% by mass or more, the adhesion can be suppressed, adhesive residue and stop marks are less likely to occur, and the adhesive surfaces tend to be easily peeled from each other, which is preferable. The thermoplastic elastomer (E) may contain only one type of styrene monomer unit, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range. The method for measuring the content of styrene monomer units in the thermoplastic elastomer (E) of this embodiment can be found in International Publication No. 2017 / 126469, the contents of which are incorporated herein by reference. The same applies to the content of conjugated diene monomer units, etc., described below.

[0245] The thermoplastic elastomer (E) contains a conjugated diene monomer unit. The inclusion of the conjugated diene monomer unit improves the solubility of the thermoplastic elastomer (E) in the resin composition (2). The conjugated diene monomer is not particularly limited as long as it is a diolefin having one pair of conjugated double bonds. Examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and farnesene. 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. The thermoplastic elastomer (E) may contain only one type of conjugated diene monomer unit, or may contain two or more types.

[0246] In the thermoplastic elastomer (E), the mass ratio of the styrene monomer units to the conjugated diene monomer units is preferably in the range of 5 / 95 to 80 / 20, more preferably 7 / 93 to 77 / 23, and even more preferably 10 / 90 to 70 / 30. When the mass ratio of the styrene polymer units to the conjugated diene monomer units is in the range of 5 / 95 to 80 / 20, adhesion can be suppressed, high adhesion strength can be maintained, and easy peeling of the adhesive surfaces can be improved.

[0247] The thermoplastic elastomer (E) may have all of its conjugated diene bonds hydrogenated, some of them hydrogenated, or none of them hydrogenated.

[0248] The thermoplastic elastomer (E) may or may not contain other monomer units in addition to the styrene monomer units and the conjugated diene monomer units. Examples of other monomer units include aromatic vinyl compound units other than the styrene monomer units. In the thermoplastic elastomer (E), the sum of styrene monomer units and conjugated diene monomer units preferably accounts for 90% by mass or more of all monomer units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more. As described above, the thermoplastic elastomer (E) may contain only one type of styrene monomer unit and one type of conjugated diene monomer unit, or may contain two or more types. When two or more types are contained, it is preferable that the total amount is within the above range.

[0249] The thermoplastic elastomer (E) used in this embodiment may be a block polymer or a random polymer. It may also be a hydrogenated elastomer in which the conjugated diene monomer units are hydrogenated, an unhydrogenated elastomer in which the conjugated diene monomer units are not hydrogenated, or a partially hydrogenated elastomer in which the conjugated diene monomer units are partially hydrogenated, and is preferably an unhydrogenated elastomer or a partially hydrogenated elastomer. In one embodiment of this embodiment, the thermoplastic elastomer (E) is a hydrogenated elastomer. Here, the hydrogenated elastomer means, for example, a thermoplastic elastomer in which double bonds based on conjugated diene monomer units in the thermoplastic elastomer have been hydrogenated, and includes elastomers with a hydrogenation rate (hydrogenation rate) of 100% or more as well as elastomers with a hydrogenation rate of 80% or more. The hydrogenation rate in the hydrogenated elastomer is preferably 85% or more, more preferably 90% or more, and even more preferably 95% or more. In this embodiment, the hydrogenation rate is 1 It is calculated from the results of H-NMR spectroscopy. In one embodiment of this embodiment, the thermoplastic elastomer (E) is an unhydrogenated elastomer. Here, the unhydrogenated elastomer refers to an elastomer in which the proportion of hydrogenated double bonds based on conjugated diene monomer units in the elastomer, i.e., the hydrogenation rate (hydrogenation rate), is 20% or less. The hydrogenation rate is preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less. On the other hand, a partially hydrogenated elastomer means a thermoplastic elastomer in which some of the double bonds based on the conjugated diene monomer units are hydrogenated, and usually refers to a hydrogenation rate (hydrogenation rate) of less than 80% but more than 20%.

[0250] Examples of commercially available thermoplastic elastomers (E) used in the present embodiment include SEPTON (registered trademark) 2104, V9461, and S8104 manufactured by Kuraray Co., Ltd., SOE (registered trademark) S1606, S1613, S1609, and S1605 manufactured by Asahi Kasei Corporation, Tuftec (registered trademark) H1041, H1043, P2000, and MP10 manufactured by Asahi Kasei Corporation, and DYNARON (registered trademark) 9901P and TR2250 manufactured by JSR Corporation.

[0251] The elastomer used in this embodiment may also be a liquid diene. Liquid diene refers to a liquid elastomer containing a conjugated diene monomer unit. Examples of conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and farnesene. 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. Examples of the liquid diene used in this embodiment include liquid polybutadiene, liquid polyisoprene, modified liquid polybutadiene, modified liquid polyisoprene, liquid acrylonitrile-butadiene copolymer, and liquid styrene-butadiene copolymer. The number average molecular weight of the liquid diene is not particularly limited as long as it is liquid at 20°C, but is preferably 500 or more and 10,000 or less.

[0252] When the resin composition (2) contains a thermoplastic elastomer (preferably, thermoplastic elastomer (E)), the content thereof is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and may be 12 parts by mass or more, per 100 parts by mass of the resin solid content in the resin composition (2). By setting the content at or above the lower limit, the dielectric properties (low dielectric tangent) of the second insulating resin layer tend to be further improved. Furthermore, the upper limit of the content of the thermoplastic elastomer is preferably 45 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, per 100 parts by mass of the resin solid content in the resin composition (2). By setting the content at or below the upper limit, the heat resistance of the second insulating resin layer tends to be further improved. The resin composition (2) may contain only one type of thermoplastic elastomer or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0253] <<Styrene-based oligomer>> In order to improve the low dielectric constant and the low dielectric loss tangent, the resin composition (2) may contain a styrene oligomer. However, a component that corresponds to the other components specified in this specification and also corresponds to the styrene oligomer is classified as the other component. The styrene-based oligomer according to this embodiment is a compound obtained by polymerizing at least one selected from the group consisting of styrene and styrene derivatives (α-methylstyrene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexylstyrene, etc.), and vinyltoluene, and has a number average molecular weight of 178 to 1600, an average number of aromatic rings of 2 to 14, the total amount of the aromatic rings of 2 to 14 being 50 mass% or more, and a boiling point of 300°C or more, and preferably has no branched structure. Styrenic oligomers are generally thermoplastic. Styrenic oligomers do not have polymerizable carbon-carbon unsaturated double bonds. However, compounds that fall under the category of styrenic oligomers and also fall under the category of thermosetting compounds are considered to be thermosetting compounds.

[0254] For details of the styrene-based oligomer, please refer to paragraphs 0065 to 0067 of WO 2019 / 230945 and paragraphs 0253 to 0245 of WO 2023 / 176765, the contents of which are incorporated herein by reference.

[0255] When the resin composition (2) contains a styrene-based oligomer, the content thereof is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and even optionally 5 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition (2). By ensuring that the content is equal to or greater than the lower limit, the low dielectric properties (Dk and / or Df) of the resulting cured product (insulating resin layer) tend to be further improved. Furthermore, the upper limit for the content of the styrene-based oligomer is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition (2). By ensuring that the content is equal to or less than the upper limit, the heat resistance tends to be further improved. Furthermore, the low dielectric properties (Dk and / or Df) and chemical resistance of the resulting cured product (insulating resin layer) tend to be further improved. The resin composition (2) may contain only one type of styrene-based oligomer, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0256] <<Filling material>> The resin composition (2) may contain a filler, which can further improve the physical properties of the resin composition (2) and its cured product, such as dielectric properties (low dielectric constant, low dielectric loss tangent, etc.), flame resistance, and low thermal expansion. The filler that may be contained in the resin composition (2) has the same meaning as the filler that may be contained in the resin composition (1), and the preferred range is also the same.

[0257] The content of the filler in the resin composition (2) can be appropriately set depending on the desired properties and is not particularly limited. It is preferably 0 parts by mass or more, more preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 40 parts by mass or more, even more preferably 60 parts by mass or more, and even more preferably 80 parts by mass or more, relative to 100 parts by mass of the resin solid content in the resin composition (1). By setting the filler content at or above the lower limit, the heat resistance, low thermal expansion, and dielectric loss tangent of the first insulating resin layer tend to be further improved. The upper limit of the filler content is preferably 300 parts by mass or less, more preferably 200 parts by mass or less, even more preferably 150 parts by mass or less, even more preferably 120 parts by mass or less, and may be 50 parts by mass or less, or 20 parts by mass or less, relative to 100 parts by mass of the resin solid content in the resin composition (1). Setting the filler content at or below the upper limit tends to further improve the moldability of the first insulating resin layer. In the resin composition (2), one preferred embodiment is one in which the content of the filler is 30% by mass to 90% by mass of the components excluding the solvent. In the resin composition (2), another preferred embodiment is one in which the content of the filler is 0 to 50 mass % (preferably 0 to 45 mass %, more preferably 0 to 40 mass %) of the mass of the resin solid content. The resin composition (2) may contain only one type of filler or may contain two or more types. When two or more types are contained, the total amount is preferably in the above range.

[0258] <<Flame retardants>> The resin composition (2) may contain a flame retardant. Examples of the flame retardant include phosphorus-based flame retardants, halogen-based flame retardants, inorganic flame retardants, and silicone-based flame retardants, and phosphorus-based flame retardants are preferred. The flame retardant that may be contained in the resin composition (2) has the same meaning as the flame retardant that may be contained in the resin composition (1), and the preferred range (including the preferred content) is also the same.

[0259] <<Activated ester compounds>> The resin composition (2) may contain an active ester compound. The active ester compound that may be contained in the resin composition (2) has the same meaning as the active ester compound that may be contained in the resin composition (1), and the preferred range (including the preferred content) is also the same.

[0260] <<Dispersant>> The resin composition (2) may contain a dispersant. The dispersant that may be contained in the resin composition (2) has the same meaning as the dispersant that may be contained in the resin composition (1), and the preferred range (including the preferred content) is also the same.

[0261] <<Curing accelerator>> The resin composition (2) may further contain a curing accelerator. The curing accelerator that may be contained in the resin composition (2) has the same meaning as the curing accelerator that may be contained in the resin composition (1), and the preferred range (including the preferred content) is also the same.

[0262] <<Solvent>> The resin composition (2) may contain a solvent, and preferably contains an organic solvent. The solvent that may be contained in the resin composition (2) has the same meaning as the solvent that may be contained in the resin composition (1), and the preferred range (including the preferred content) is also the same.

[0263] <<Other resin additive ingredients>> In addition to the above components, the resin composition (2) may contain various polymeric compounds such as oligomers of thermoplastic resins, and various additives. Examples of additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, photosensitizers, colorants (dyes and pigments), thickeners, flow control agents, lubricants, antifoaming agents, leveling agents, gloss agents, and polymerization inhibitors such as quinones, phenols, nitrosoamines, and hydroxyamines. These additives may be used alone or in combination of two or more.

[0264] <Metal foil> The multilayer body of the present embodiment may have a metal foil, that is, the multilayer body of the present embodiment may be a metal foil-clad laminate (sometimes called a metal foil-clad laminate). The metal foil is preferably one used as a material for printed wiring boards, such as rolled copper foil or electrolytic copper foil. The thickness of the metal foil (preferably copper foil) is not particularly limited and may be approximately 1.5 to 70 μm. When copper foil is used as the metal foil, the copper foil preferably has a surface roughness Rz of 0.2 to 4.0 μm, as measured in accordance with JIS B0601:2013. By setting the surface roughness Rz to 0.2 μm or more, the copper foil surface roughness becomes appropriate, and the copper foil peel strength tends to be further improved. On the other hand, by setting the surface roughness Rz to 4.0 μm or less, the copper foil surface roughness becomes appropriate, and the dielectric loss tangent characteristics of the resulting cured product tend to be further improved. From the viewpoint of the dielectric loss tangent characteristics and copper foil peel strength of the resulting cured product, the roughness Rz of the copper foil surface is more preferably 0.5 μm or more, even more preferably 0.6 μm or more, and particularly preferably 0.7 μm or more, and is more preferably 3.5 μm or less, even more preferably 3.0 μm or less, and particularly preferably 2.0 μm or less.

[0265] The multilayer body of this embodiment can be suitably used as a low dielectric constant material and / or a low dielectric loss tangent material, as an insulating resin layer for printed wiring boards, a semiconductor package material, etc., and as a resin composition for electronic materials. The multilayer body of this embodiment can be suitably used as a material for metal foil-clad laminates, resin composite sheets, and printed wiring boards. Therefore, this embodiment discloses a printed wiring board including the multilayer body of this embodiment, and also a semiconductor device including the printed wiring board of this embodiment.

[0266] <Method of manufacturing a multilayer body> Next, a method for producing the multilayer body of this embodiment will be described. The method for producing a multilayer body of this embodiment includes providing metal wiring on the surface of a first insulating resin layer and providing a second insulating resin layer on the surface of the first insulating resin layer so as to cover the metal wiring. Furthermore, in the method for producing a multilayer body of this embodiment, when providing the metal wiring on the surface of the first insulating resin layer, it is preferable that a metal foil is provided on the surface of the first insulating resin layer opposite to the side on which the metal wiring is provided. Furthermore, when providing the second insulating resin layer so as to cover the metal wiring, it is preferable that a metal foil is provided on the surface of the second insulating resin layer opposite to the side on which the metal wiring is covered. Furthermore, when providing the second insulating resin layer so as to cover the metal wiring, it is also preferable that a protective film is provided on the surface of the second insulating resin layer opposite to the side on which the metal wiring is covered. The protective film is preferably a thermoplastic resin film, more preferably a polyethylene terephthalate resin film.

[0267] A method for manufacturing the multilayer body of this embodiment will be described below with reference to Fig. 3. It goes without saying that the multilayer body of this embodiment is not limited to the form shown in Fig. 3. In Fig. 3, the same components as in Figs. 1 and 2 are designated by the same reference numerals. In Fig. 3, for convenience, the metal foil of the metal foil-clad insulating resin layer that is peeled off during the manufacturing process of the multilayer body is designated by reference numeral 51. However, it goes without saying that the metal foil designated by reference numeral 5 may also be peeled off depending on the application of the multilayer body, etc.

[0268] In forming the multilayer body of this embodiment, typically, one of the metal foils 51 on both surfaces of the metal foil-equipped first insulating resin layer 7, which has metal foils 51 on both surfaces of the first insulating resin layer 2, is removed, and then the metal wiring 4 is provided. Preferably, after providing the metal wiring 4, the remaining metal foil 51 on the metal foil-equipped first insulating resin layer 7 is also removed (FIG. 3(a)). By providing the metal wiring 4 and then removing the remaining metal foil 51 on the other metal foil-equipped first insulating resin layer 7, multilayering becomes possible. Alternatively, the metal wiring 4 may also be provided on the other surface of the first insulating resin layer 2 (not shown). Typically, one of the metal foils 51 of the metal foil-clad second insulating resin layer 3, which has metal foils 5 and 51 on both surfaces of the second insulating resin layer 3, is removed (not shown). Next, the second insulating resin layer side of the second insulating resin layer 3, which has the metal foil 5 on one surface, is bonded to the first insulating resin layer 2 from which the metal foil 51 has been removed (FIG. 5(b)). At this time, if the first insulating resin layer 2 has metal wiring 4 on its surface, the second insulating resin layer 3 is bonded so as to cover the metal wiring 4. In this manner, it is preferable to manufacture the first insulating resin layer 2 and the second insulating resin layer 3 as semi-cured metal foil-clad laminates, remove the metal foils 51 and 51 from both layers, and then bond the second insulating resin layer 3 and the first insulating resin layer 2 together. This configuration allows the materials of the second insulating resin layer 3 and the first insulating resin layer 2 to be bonded in a semi-cured state, preventing the two materials from intermixing, thereby more effectively reducing transmission loss.

[0269] 3(b), the second insulating resin layer 3 is bonded to each of both surfaces of the first insulating resin layer 2, but the second insulating resin layer 3 may be bonded to only one surface of the first insulating resin layer 2. When the second insulating resin layer 3 is bonded to only one surface of the first insulating resin layer 2, the metal foil 51 on only one surface of the first insulating resin layer 2 may be removed. In the multilayer body of this embodiment, the process of removing the metal foils 51·51 of the metal foil-fitted first insulating resin layer 7, which has metal foils 51·51 on both surfaces of the first insulating resin layer 2, and the process of removing the metal foil of the metal foil-fitted second insulating resin layer (not shown), which has metal foils 5·51 on both surfaces of the second insulating resin layer 3, may be carried out simultaneously, or either may be carried out first. The metal foil is preferably removed by etching.

[0270] In addition, instead of the second insulating resin layer having metal foil on both surfaces thereof, a second insulating resin layer having metal foil on one surface thereof and a protective film on the other surface thereof may be used. In this case, it is preferable to peel off the protective film and bond it to the first insulating resin layer.

[0271] Furthermore, in the step of bonding the first insulating resin layer 2 and the second insulating resin layer 3, it is preferable to bond them so that they are in face-to-face contact and so that the metal wiring 4 is covered by the second insulating resin layer 3. Examples of bonding methods include lamination molding using a multi-stage press, multi-stage vacuum press, continuous molding machine, autoclave molding machine, or the like at a temperature of about 180 to 350°C, a heating time of about 100 to 300 minutes, and a surface pressure of about 1 to 10 MPa.

[0272] In the method for producing the multilayer body of this embodiment, it is also preferable to further form metal wiring 4 on the surface of the second insulating resin layer 3, as shown in FIG. 2 above. By forming metal wiring 4 on the surface of the second insulating resin layer 3 in this way, it is preferably used as a printed wiring board. In this case, it is preferable to further provide a new second insulating resin layer 3 on the surface of the metal wiring 4. The second and subsequent second insulating resin layers 3 are similar to the matters described in the section on the second insulating resin layer, and the preferred ranges are also similar. These multiple second insulating resin layers 3 may be the same as or different from each other. More specifically, an inner layer circuit is formed on the surface of the multilayer body of this embodiment, and this circuit is blackened to form an inner layer circuit. Then, the inner layer circuit and the multilayer body of this embodiment are alternately arranged one by one, and copper foil is further arranged as the outermost layer, and laminate molding is performed under the above conditions, preferably in vacuum, to produce a multilayer body. The method for producing a multilayer body of this embodiment can be suitably used as a method for producing a printed wiring board.

[0273] This embodiment also relates to a semiconductor device including the printed wiring board. For details of the semiconductor device, please refer to paragraphs 0200 to 0202 of Japanese Patent Laid-Open No. 2021-021027, the contents of which are incorporated herein by reference. [Example]

[0274] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0275] <Synthesis Example 1: Synthesis of α-naphthol aralkyl cyanate ester compound (SNCN)> 0.47 mol (OH group equivalent) of α-naphthol aralkyl resin (SN495V, OH group equivalent: 236 g / eq., manufactured by Nippon Steel Chemical Co., Ltd.; the number of naphthol aralkyl repeating units ranges from 1 to 5) was dissolved in 500 mL of chloroform, and 0.7 mol of triethylamine was added to this solution to prepare Solution 1. While maintaining the temperature at -10°C, Solution 1 was added dropwise over 1.5 hours to 300 g of a chloroform solution of 0.93 mol of cyanogen chloride placed in a reactor. After the addition was complete, the mixture was stirred for 30 minutes. A mixed solution of 0.1 mol of triethylamine and 30 g of chloroform was then added dropwise to the reactor, and the mixture was stirred for 30 minutes to complete the reaction. The by-product triethylamine hydrochloride was filtered off from the reaction solution, and the resulting filtrate was washed with 500 mL of 0.1 N hydrochloric acid and then with 500 mL of water four times. This was dried over sodium sulfate, evaporated at 75°C, and further degassed under reduced pressure at 90°C to obtain a brown solid α-naphthol aralkyl cyanate ester compound represented by formula (S1) (R C1 ~R C4 are all hydrogen atoms, and n c The compound was a mixture of 1 to 5 (cyanate equivalent: 261 g / eq.). The obtained α-naphthol aralkyl cyanate ester compound was analyzed by infrared absorption spectroscopy, revealing a peak at 2264 cm -1 Absorption of cyanate ester groups was confirmed in the vicinity. [ka]

[0276] <Synthesis Example 2: Synthesis of polymer (va) having a structural unit represented by formula (V)> 2.25 moles (292.9 g) of divinylbenzene, 1.32 moles (172.0 g) of ethylvinylbenzene, 11.43 moles (1190.3 g) of styrene, and 15.0 moles (1532.0 g) of n-propyl acetate were charged into a reactor, and 600 mmol of boron trifluoride diethyl ether complex was added at 70 °C. The reaction was allowed to proceed for 4 hours. After the polymerization reaction was terminated with aqueous sodium bicarbonate, the oil layer was washed three times with pure water and devolatilized under reduced pressure at 60 °C to recover polymer (va) having structural units represented by formula (V). The resulting polymer (va) having structural units represented by formula (V) was weighed, confirming that 860.8 g of polymer (va) having structural units represented by formula (V) was obtained.

[0277] The resulting polymer (va) having a structural unit represented by formula (V) had a number average molecular weight Mn of 2,060, a weight average molecular weight Mw of 30,700, and a monodispersity index Mw / Mn of 14.9. 13 C-NMR and 1 By performing H-NMR analysis, resonance lines derived from each monomer unit used as a raw material were observed in the polymer (va) having a structural unit represented by formula (V). Based on the NMR measurement results and GC analysis results, the proportion of each monomer unit (structural unit derived from each raw material) in the polymer (va) having a structural unit represented by formula (V) was calculated as follows: Divinylbenzene-derived structural units: 20.9 mol% (24.3 mass%) Structural units derived from ethylvinylbenzene: 9.1 mol% (10.7 mass%) Structural units derived from styrene: 70.0 mol% (65.0 mass%) Furthermore, the content of structural units having residual vinyl groups derived from divinylbenzene was 16.7 mol % (18.5 mass %).

[0278] <Measurement of weight average molecular weight and number average molecular weight> The weight-average molecular weight and number-average molecular weight were measured by gel permeation chromatography (GPC) using a pump (Shimadzu Corporation, LC-20AD), a refractive index detector (Shimadzu Corporation, RID-10A), and GPC columns (Showa Denko K.K., GPC KF-801, 802, 803, 804) with tetrahydrofuran as the solvent, a flow rate of 1.0 mL / min, a column temperature of 40°C, and a calibration curve based on monodisperse polystyrene.

[0279] Example 1 <Manufacture of copper foil clad laminate (1-1)> According to Example 1 of WO 2020 / 022084, a prepreg formed from an S-glass woven fabric (thickness 100 μm) and a resin composition (1-1) was produced. Specifically, it was produced as follows. First, 5.3 parts by mass of diallyl bisphenol A (DABPA, Daiwa Chemical Industry Co., Ltd.), 5.8 parts by mass of biscresol fluorene (BCF, Osaka Gas Chemical Co., Ltd.), 4.4 parts by mass of epoxy-modified silicone 1 (X-22-163, Shin-Etsu Chemical Co., Ltd., functional group equivalent: 200 g / mol), 8.7 parts by mass of epoxy-modified silicone 2 (KF-105, Shin-Etsu Chemical Co., Ltd., functional group equivalent: 490 g / mol), 5.8 parts by mass of biphenyl-type epoxy compound (YL-6121H, Mitsubishi Chemical Corporation), and 30 parts by mass of propylene glycol monomethyl ether acetate (DOWANOLPMA, Dow Chemical Japan Co., Ltd.) as a solvent were placed in a three-neck flask equipped with a thermometer and a Dimroth trap, and the mixture was heated to 120 °C in an oil bath with stirring. After confirming that the raw materials had dissolved in the solvent, 0.3 parts by mass of imidazole catalyst g1 (TBZ, Shikoku Chemical Industry Co., Ltd.) was added and the temperature was raised to 140°C, followed by stirring for 5 hours. After cooling, a phenoxy polymer solution (solid content 50% by mass) was obtained (polymer production process).

[0280] 30 parts by mass (solids equivalent) of this phenoxy polymer solution was mixed with 26 parts by mass of the α-naphthol aralkyl cyanate ester compound (SNCN) (cyanate equivalent: 261 g / eq.) obtained in Synthesis Example 1, 17 parts by mass of a novolak maleimide compound (BMI-2300, Daiwa Chemical Industry Co., Ltd.), 27 parts by mass of a naphthylene ether epoxy compound (HP-6000, DIC Corporation), 100 parts by mass of spherical silica (SFP-130MC, Denka Co., Ltd.), 40 parts by mass of spherical silica (SC-4500SQ, Admatechs Co., Ltd.), 1 part by mass of a wetting and dispersing agent (DISPERBYK-161, BYK Japan Co., Ltd.), and 5 parts by mass of a silane coupling agent (KMB-403, Shin-Etsu Chemical Co., Ltd.) to obtain a varnish (resin composition (1-1)) (varnish production step). This varnish was applied to a glass cloth (S-glass woven fabric, thickness 100 μm) by impregnation, and then heated and dried at 150°C for 3 minutes to obtain a prepreg of insulating resin layer (1-1) (solid content (including filler) 46% by mass) (prepreg production step).

[0281] Eight sheets of the prepreg obtained above were stacked, and electrolytic copper foil (3EC-M2S-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) with a thickness of 12 μm was placed on top and bottom of the stack. The pressure was 30 kgf / cm. 2 Lamination molding was carried out at a temperature of 220° C. for 120 minutes to obtain a copper foil-clad laminate (1-1) having an insulating resin layer (1-1) with a thickness of 0.8 mm formed from the resin composition (1-1).

[0282] <Measurement of dielectric loss tangent (Df)> The copper foils on both sides of the copper foil-clad laminate (1-1) were removed by etching, and the laminate was dried at 120°C for 60 minutes. The dielectric loss tangent (Df) of the dried laminate was measured at 10 GHz using a perturbation cavity resonator. The measurement temperature was 23°C. The perturbation method cavity resonator used was Agilent8722ES manufactured by Agilent Technologies. The relative dielectric constant (Dk) can also be measured in a similar manner. The evaluation was made in the following categories: <<Dielectric loss tangent (Df)>> A: 0.005 or less B: More than 0.005 and less than 0.008 C: More than 0.008 and less than 0.011 D: over 0.011

[0283] <Thermal expansion coefficient> The coefficient of linear thermal expansion (CTE) was determined by the TMA method (Thermo-Mechanical Analysis) specified in JIS C 6481 5.19 as follows. Specifically, the copper foil on both sides of the copper foil-clad laminate (1-1) obtained above was removed by etching, and the resulting sample was cut (downsized) to 5.0 mm × 5.0 mm × 0.8 mm for evaluation. The temperature was raised from 30°C to 320°C at a rate of 10°C per minute using a thermomechanical analyzer (TA Instruments, TMA Q-400), and the coefficient of thermal expansion in the thickness direction (CTE(Z)) (unit: ppm / °C) from 50°C to 280°C was measured. ppm is a volume ratio. Other details are in accordance with JIS C 6481 5.19. Evaluation was performed as follows. ppm is a volume ratio. Other details comply with JIS C 6481 5.19. The evaluation was carried out as follows. The evaluation results are shown in Table 1. A: 10ppm / ℃ or less B: More than 10ppm / ℃ and less than 15ppm / ℃ C: More than 15pm / ℃ and less than 20ppm / ℃ D: More than 20ppm / ℃

[0284] <Production of copper foil (2) with insulating resin layer (2)> 5 parts by mass of a maleimide compound (MIR-3000, manufactured by Nippon Kayaku Co., Ltd., corresponding to the compound represented by formula (M3)), 29 parts by mass of a maleimide compound (ma) shown in the structure below (NE-X-9470S, manufactured by DIC Corporation, corresponding to the compound represented by formula (M1)), 30 parts by mass of the polymer (va) having a structural unit represented by formula (V) obtained in Synthesis Example 2, 15 parts by mass of a hydrogenated styrene-based thermoplastic elastomer (SEBS, block copolymer, SEPTON 2104, Mn 83000, manufactured by Kuraray Co., Ltd.), and the α-naphthol aralkyl cyanate ester compound (SNCN) obtained in Synthesis Example 1 (cyanate equivalent: 261 g / eq.). 5 parts by mass of a phosphorus-based flame retardant (PX-200, Daihachi Chemical Industry Co., Ltd.), 15 parts by mass of N-phenylmaleimide (Tokyo Chemical Industry Co., Ltd., product number: P0900), 0.3 parts by mass of a wetting and dispersing agent (BYK Corporation, BYK-2009), 0.5 parts by mass of a wetting and dispersing agent (DISPERBYK-161, BYK Japan Co., Ltd.), and 100 parts by mass of a methyl ethyl ketone (MEK) slurry of vinylsilane-treated silica (SC2050MNU (trade name), median diameter 0.5 μm, nonvolatile content 70% by mass, Admatechs Co., Ltd.) were dissolved and dispersed in methyl ethyl ketone and mixed to obtain a varnish (resin composition (2)). Note that the amounts added above indicate the solid content.

[0285] Maleimide compounds (MA) [ka] n is an integer of 1 to 20. The obtained varnish was applied by bar coater coating onto the ultrathin copper foil surface of an ultrathin copper foil with a carrier copper foil (ultrathin copper foil thickness 1.5 μm, surface roughness Rz 1.3 μm, carrier copper foil thickness 18 μm, MT-FL, manufactured by Mitsui Mining & Smelting Co., Ltd.), and dried at 130° C. for 3 minutes to obtain a copper foil (2) with an insulating resin layer (2) having a thickness of 20 μm. In the same manner as above, the dielectric loss tangent (Df) and the thermal expansion coefficient of the cured insulating resin layer (2) were measured. The evaluation categories were as follows:

[0286] <<Dielectric loss tangent (Df)>> A: 0.005 or less B: More than 0.005 and less than 0.008 C: More than 0.008 and less than 0.011 D: over 0.011 <<Thermal expansion coefficient>> A: 10ppm / ℃ or less B: More than 10ppm / ℃ and less than 15ppm / ℃ C: More than 15pm / ℃ and less than 20ppm / ℃ D: More than 20ppm / ℃

[0287] <Manufacturing of multilayer bodies> The copper foils on both sides of the copper foil-clad laminate (1-1) and one of the copper foils (2) with the insulating resin layer (2) were removed by etching, and the copper foils (2) with the insulating resin layer (2) were placed so that the insulating resin layer (2) of each of the copper foils (2) with the insulating resin layer (2) faced both sides of the insulating resin layer (1-1) of the copper foil-clad laminate (1-1), respectively, and a pressure of 30 kgf / cm was applied. 2 The laminate was then heat-pressed at 220° C. for 120 minutes to obtain a multilayer structure consisting of copper foil / insulating resin layer (2) / insulating resin layer (1-1) / insulating resin layer (2) / copper foil.

[0288] <Dielectric loss tangent (Df)> The linear expansion coefficient of the obtained multilayer body was measured by the same method as in <Measurement of dielectric loss tangent (Df)> above. The evaluation was carried out as follows. The evaluation results are shown in Table 1.

[0289] <<Dielectric loss tangent (Df)>> A: 0.005 or less B: More than 0.005 and less than 0.008 C: More than 0.008 and less than 0.011 D: over 0.011 <Thermal expansion coefficient> The linear expansion coefficient of the obtained multilayer body was measured by the same method as in the above <Coefficient of thermal expansion>. The evaluation was carried out as follows. The evaluation results are shown in Table 1. A: 10ppm / ℃ or less B: More than 10ppm / ℃ and less than 15ppm / ℃ C: More than 15pm / ℃ and less than 20ppm / ℃ D: More than 20ppm / ℃

[0290] <Skew measurement> Only one side of the copper foil of the multilayer structure consisting of copper foil / insulating resin layer (2) / insulating resin layer (1-1) / insulating resin layer (2) / copper foil obtained above was etched to form 15 microstrip lines with a circuit length of 10 cm. The transmission speed of the 15 conductor wirings (impedance 50 Ω) was measured from 10 GHz to 40 GHz, and the difference between the maximum and minimum values ​​was calculated as the skew (SKEW). A: The difference between the maximum and minimum values ​​is 5.0x10 ー12 s or less B: The difference between the maximum and minimum values ​​is 5.0x10 ー12 s super 10.0x10 ー12 s or less C: The difference between the maximum and minimum values ​​is 10.0x10 ー12 s super

[0291] <Transmission loss measurement> A wiring board was fabricated by etching only one side of the copper foil of the multilayer structure consisting of copper foil / insulating resin layer (2) / insulating resin layer (1-1) / insulating resin layer (2) / copper foil obtained above to form a microstrip line with a circuit length of 10 cm, and the transmission characteristics were evaluated. A high-frequency signal was transmitted using a network analyzer N5227B manufactured by Keysight Technology, and the transmission loss at 40 GHz was measured. A: 0.7dB / cm or less B: More than 0.7dB / cm and less than 1.0dB / cm C: More than 1.0dB / cm

[0292] Example 2 The same procedure as in Example 1 was carried out except that the prepreg used for the insulating resin layer (1-1) was changed to the prepreg shown below to form the insulating resin layer (1-2). A mixture of 1 part by mass of alumina nanoparticles surface-treated with a polysiloxane-based modifier (product name "NANOBYK-3610", average particle size: 20 nm, manufactured by BYK Japan K.K.), 300 parts by mass of spherical fused silica (product name "FB-3SDC", average particle size: 3.0 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.), 100 parts by mass of spherical fused silica (SFP-120MC, average particle size: 0.3 μm, manufactured by Denki Kagaku Kogyo Co., Ltd.), 36 parts by mass of the α-naphthol aralkyl cyanate ester compound (SNCN) (cyanate equivalent: 261 g / eq.) obtained in Synthesis Example 1, and a maleimide compound (product name "BMI-2300") was used. 26 parts by mass of ), 38 parts by mass of polyoxynaphthylene epoxy resin (product name "HP-6000", epoxy equivalent: 250 g / eq., manufactured by DIC Corporation), 1 part by mass of wetting and dispersing agent 1 (product name "disperbyk-161", manufactured by BYK Japan Co., Ltd.), 2 parts by mass of wetting and dispersing agent 2 (product name "disperbyk-111", manufactured by BYK Japan Co., Ltd.), 5 parts by mass of silane coupling agent (product name "Z6040", manufactured by Toray Dow Coating Co., Ltd.), and 1 part by mass of 2,4,5-triphenylimidazole (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed to obtain a varnish (resin composition (1-2)). This varnish was diluted with methyl ethyl ketone, impregnated into a 0.1 mm thick E-glass woven fabric, and dried by heating at 140°C for 3 minutes to obtain a prepreg of insulating resin layer (1-2) (solid content (including filler) 63% by mass).

[0293] Comparative Example 1 In Example 1, the copper foil clad laminate (1-1) was used instead of the copper foil clad laminate (2) (both copper foil clad laminates (1-1) were used as copper foil clad laminates), and the dielectric loss tangent (Df), thermal expansion coefficient, skew, and transmission loss were measured in the same manner as in Example 1.

[0294] [Table 1]

[0295] In Table 1 above, ΔDf represents Df of the first insulating resin layer - Df of the second insulating resin layer,

[0296] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. [Explanation of symbols]

[0297] 1 Multilayer body 2. First insulating resin layer 3 Second insulating resin layer 4 Metal wiring 5 Metal foil 51 Metal foil 5 Metal wiring 7. First insulating resin layer with metal foil

Claims

1. A multilayer body comprising: a first insulating resin layer; metal wiring provided on a surface of the first insulating resin layer; and a second insulating resin layer provided on the surface of the first insulating resin layer and covering the metal wiring, wherein the dielectric loss tangent of the second insulating resin layer at a frequency of 10 GHz measured with a perturbation method cavity resonator is lower than the dielectric loss tangent of the first insulating resin layer at a frequency of 10 GHz measured with the perturbation method cavity resonator.

2. 2. The multilayer body according to claim 1, wherein the first insulating resin layer has a thermal expansion coefficient of 30 ppm / ° C. or less as measured according to a thermo-mechanical analysis (TMA) method.

3. The multilayer body according to claim 1 , wherein the difference between the dielectric loss tangent of the second insulating resin layer and the dielectric loss tangent of the first insulating resin layer is 0.002 or more.

4. the thermal expansion coefficient of the first insulating resin layer measured in accordance with a thermo-mechanical analysis (TMA) method is 30 ppm / °C or less; The multilayer body according to claim 1 , wherein the difference between the dielectric loss tangent of the second insulating resin layer and the dielectric loss tangent of the first insulating resin layer is 0.002 or more.

5. The multilayer body according to any one of claims 1 to 4, wherein the first insulating resin layer includes a fiber base material.

6. The multilayer body according to any one of claims 1 to 4, wherein the first insulating resin layer is a layer formed from a resin composition (1) containing a thermosetting compound and a fiber substrate.

7. The multilayer body according to any one of claims 1 to 4, wherein the second insulating resin layer does not contain a fiber base material.

8. The second insulating resin layer is a layer formed from a resin composition (2), The resin composition (2) contains a thermosetting compound, and the content of the filler is 0 to 40 mass% of the mass of the resin solid content contained in the resin composition (2).

9. 5. The multilayer body according to claim 1, wherein the second insulating resin layer is disposed so as to be in contact with both surfaces of the first insulating resin layer.

10. The multilayer body according to claim 9 , further comprising a metal foil disposed in contact with the surface of the second insulating resin layer opposite to the first insulating resin layer.

11. the thermal expansion coefficient of the first insulating resin layer measured in accordance with a thermo-mechanical analysis (TMA) method is 30 ppm / °C or less; a difference between the dielectric loss tangent of the second insulating resin layer and the dielectric loss tangent of the first insulating resin layer is 0.002 or more; the first insulating resin layer is a layer formed from a resin composition (1) containing a thermosetting compound and a fiber base material, the second insulating resin layer does not contain a fiber base material, The second insulating resin layer is a layer formed from a resin composition (2), the resin composition (2) contains a thermosetting compound, and the content of the filler is 0 to 40 mass% of the mass of the resin solid content contained in the resin composition (2); the second insulating resin layer is disposed on both surfaces of the first insulating resin layer so as to be in contact with the first insulating resin layer; a metal foil is further disposed so as to be in contact with the surface of the second insulating resin layer opposite to the first insulating resin layer; The multilayer body according to claim 1 .

12. the first insulating resin layer is a layer formed from a resin composition (1) and a fiber base material, and the resin composition (1) is in a cured state; the second insulating resin layer is a layer formed from a resin composition (2), and the resin composition (2) is in a cured state; The resin composition (1) contains a thermosetting compound, The multilayer body according to any one of claims 1 to 4 and 11, wherein the resin composition (2) contains a thermosetting compound, and the content of the filler is 0 to 40 mass% of the mass of the resin solid content contained in the resin composition (2).

13. providing metal wiring on the surface of the first insulating resin layer; The method for producing a multilayer body according to any one of claims 1 to 4 and 11, further comprising providing a second insulating resin layer on the surface of the first insulating resin layer so as to cover the metal wiring.

14. The method for producing a multilayer body according to claim 13, wherein when providing metal wiring on the surface of the first insulating resin layer, a metal foil is provided on the surface of the first insulating resin layer opposite to the side on which the metal wiring is provided.

15. 15. The method for producing a multilayer body according to claim 14, comprising the steps of: providing metal wiring on a surface of the first insulating resin layer; removing the metal foil on a surface of the first insulating resin layer opposite to the side on which the metal wiring is provided; and providing metal wiring on a surface of the first insulating resin layer on which the metal wiring is not provided; or providing a second insulating resin layer.

16. A printed wiring board comprising the multilayer body according to any one of claims 1 to 4 and 11.

17. A semiconductor device comprising the printed wiring board according to claim 16.

18. A method for producing a printed wiring board, comprising the method for producing the multilayer body according to claim 14.

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