JP5625635B2 - MULTILAYER PRINTED WIRING BOARD AND METHOD FOR MANUFACTURING THE SAME, PREPREG, METAL FILMS WITH RESIN, RESIN FILM - Google Patents

Description

  The present invention relates to a multilayer printed wiring board and a method for producing the same, a prepreg, a metal foil with resin, a resin film, and a metal foil-clad laminate.

  With the rapid spread of information terminal electronic devices, electronic devices are becoming smaller and thinner. In addition, the demand for higher density and thinner printed wiring boards is increasing. Furthermore, with the enhancement of functionality of electronic devices such as mobile phones, it has become necessary to connect various high-performance modules such as cameras and high-density printed wiring boards.

Furthermore, the number of electronic component mounting points has also increased rapidly, and a large number of electronic components are mounted in a limited space on the printed wiring board. Therefore, not only conventional rigid printed wiring boards but also flexible boards that can be bent freely. Is required.
Conventional rigid printed wiring boards can be bent somewhat, but glass cloth and glass nonwoven fabric are used, and it is impossible to bend them.

  On the other hand, a thermoplastic resin film centered on polyimide is mainly used as a bendable printed wiring board material. However, a thermoplastic resin such as polyimide may have a low adhesiveness with a metal foil constituting a circuit or the like, and a printed wiring board material may be formed by laminating a plurality of resin layers having different physical property values as an adhesive layer. Many.

  In addition, for the purpose of circuit protection and improvement of bending characteristics, a method of bonding another resin film having excellent flexibility on a resin film formed with a circuit is used. In general, the resin film for bonding uses a resin composition different from the resin film on which the circuit is formed. Further, in order to improve the adhesion between the resin films, the side in contact with the resin film surface on which the circuit is formed is used. In many cases, another resin layer is formed. In multilayer printed wiring boards using such film substrates, bonding using different materials becomes prominent, and with a resin having a rigid skeleton such as polyimide, the bendability when multilayered tends to decrease significantly. Show. For these reasons, all of the conventional bendable printed wiring boards are configured such that only the wiring portion or the connection terminal portion can be bent.

  For example, a multilayer rigid flexible wiring board is known in which a flexible substrate is used as a core material and a rigid substrate is laminated on the core material via a flexible insulating material having an adhesive function (see, for example, Patent Document 1).

  Further, in a printed wiring board having a plurality of resin layers, the substrate may be warped or twisted when the metal foil is etched or bonded. Furthermore, since a plurality of resin layers made of different resin materials are bonded together, there is a problem that the process at the time of circuit processing becomes complicated compared to a single resin system. In some cases, this complexity increases the tact time for commercialization and directly affects the price increase.

JP 2006-93647 A

In such a situation, in order to incorporate printed wiring boards that will become increasingly dense in the future, in addition to bending conventional wiring parts, non-through vias and through-holes connecting the layers were provided. A multilayer printed wiring board that can be bent at any place including an area is very effective in designing the wiring board.
The present invention solves the above-mentioned problems of the prior art, and even when a bent portion is provided in a region having a through hole, a multilayer printed wiring board in which an increase in the resistance value of interlayer connection is suppressed, and a manufacturing method thereof, and It is an object to provide a prepreg, a metal foil with resin, a resin film, and a metal foil-clad laminate used for forming the multilayer printed wiring board.

Specific means for solving the above problems are as follows.
<1> A metal foil having a thickness of 3 μm to 18 μm disposed on both surfaces of a first insulating layer containing a cured resin derived from the first thermosetting resin composition and the first insulating layer. A circuit board made of the metal foil and a circuit board in which a through hole penetrating the first insulating layer is formed, and provided on at least one surface of the circuit board, a glycidyl acrylate resin and a polyamideimide resin A second insulating layer having a thickness of 7 μm to 60 μm including a cured resin derived from a second thermosetting resin composition containing at least one thermosetting resin selected from: A multilayer printed wiring board comprising a bent portion in which at least one of a through hole and a non-through via is provided in a region where the circuit board and the second insulating layer are laminated.

<2> At least one of the first thermosetting resin composition and the second thermosetting resin composition includes at least one thermosetting resin having a weight average molecular weight of 10,000 to 1500,000. 1>. The multilayer printed wiring board according to 1>.

<3> The multilayer printed wiring board according to <1> or <2>, wherein the first thermosetting resin composition and the second thermosetting resin composition have the same resin composition.
<4> The multilayer printed wiring board according to any one of <1> to <3>, wherein the second insulating layer has a metal foil on a surface opposite to a surface facing the circuit board. is there.
<5> The multilayer printed wiring board according to any one of <1> to <4>, having four or more circuit layers and at least one of a through hole and a non-through via.
<6> The multilayer printed wiring board according to any one of <1> to <5>, having a through hole penetrating all layers.

<7> A metal foil having a thickness of 3 μm to 18 μm disposed on both surfaces of a first insulating layer containing a cured resin derived from the first thermosetting resin composition and the first insulating layer. Forming a through hole penetrating the first insulating layer and a circuit layer made of the metal foil on a metal foil-clad laminate having a circuit board, and a circuit board on which the through hole and the circuit layer are formed A cured resin derived from a second thermosetting resin composition containing at least one thermosetting resin selected from a glycidyl acrylate resin and a polyamide-imide resin on at least one surface of There providing a second insulating layer is 7Myuemu～60myuemu, the circuit board and the second region where the insulating layer are stacked, at least one Tsuo備of through-holes and non-through vias extending through the full thickness A step of bending portions provided that a method for manufacturing a multilayer printed wiring board comprising a.

<8> A prepreg obtained by impregnating the first thermosetting resin composition into a glass woven fabric or glass nonwoven fabric having a thickness of 30 μm or less, or a prepreg laminate in which a predetermined number of the prepregs are laminated, <7> further including a step of heating and pressing a metal foil having a thickness of 3 μm to 18 μm disposed on both surfaces of the prepreg or prepreg laminate to obtain a metal foil-clad laminate. It is a manufacturing method of the multilayer printed wiring board of description.

<9> The step of providing the second insulating layer includes providing a layer made of the second thermosetting resin composition on at least one surface of the circuit board on which the through hole and the circuit layer are formed. Further, a step of arranging a metal foil on the layer made of the second thermosetting resin composition, and a layer and the metal foil made of the second thermosetting resin composition are heated and pressed to form a metal on the surface. Forming a second insulating layer having a foil. The method for manufacturing a multilayer printed wiring board according to claim 7 or 8.

<10> The step of providing the second insulating layer is a resin obtained by using the second thermosetting resin composition on at least one surface of the circuit board on which the through hole and the circuit layer are formed. Placing the attached metal foil such that the resin surface is in contact with the circuit board; and heating and pressing the resin-attached metal foil to form a second insulating layer having the metal foil on the surface. It is a manufacturing method of the multilayer printed wiring board of Claim 7 or Claim 8 containing.

<11> The multilayer printing according to any one of <7> to <10>, wherein the first thermosetting resin composition and the second thermosetting resin composition have the same resin composition. It is a manufacturing method of a wiring board.

  According to the present invention, even when a bent portion is provided in a region having a through hole, a multilayer printed wiring board in which an increase in resistance value of interlayer connection is suppressed, a manufacturing method thereof, and formation of the multilayer printed wiring board are provided. The prepreg used, the metal foil with resin, the resin film, and the metal foil-clad laminate can be provided.

It is sectional drawing which shows typically an example of the bending part in the multilayer printed wiring board of this invention. It is a schematic plan view of the multilayer printed wiring board used for evaluation of this invention. (A) is a schematic cross section in line AB of the multilayer printed wiring board used for evaluation, (B) is a schematic cross section in line CD.

In the present invention, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes.
In the present specification, numerical ranges indicated using “to” indicate ranges including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.

<Multilayer printed wiring board>
As schematically shown in FIG. 1, the multilayer printed wiring board of the present invention includes a first insulating layer 100 containing a cured resin derived from the first thermosetting resin composition, and the first insulating layer. A circuit board having a metal foil having a thickness of 1 to 35 μm disposed on both sides of the circuit board, and having a circuit layer 26 made of the metal foil and a through hole 20 penetrating the first insulating layer; A resin cured product derived from a second thermosetting resin composition that is provided on at least one surface of the circuit board and includes at least one thermosetting resin selected from a glycidyl acrylate resin and a polyamideimide resin; A second insulating layer 200 having a thickness of 80 μm or less, and in a region where the circuit board and the second insulating layer are laminated, through-holes 22 and non-through vias 24 penetrating all layers are provided. At least one Is provided with a bent portion.
By laminating a circuit board provided with a metal foil having a specific thickness and a second insulating layer having a specific thickness, including a cured resin derived from a specific thermosetting resin, When the stacked region is bent, the conductivity of the stacked region, particularly the through hole and the non-through via provided in the bent portion is suppressed.

The bent portion in the present invention is formed by bending a region where the circuit board and the second insulating layer are laminated by 180 ° so that the same surface of the region is opposed, and the curvature radius is 0 to 25 mm. Means a range. Note that a curvature radius of 0 mm means a so-called “goat folded” state.
Further, from the viewpoint of practical use, the bent portion needs to be bendable not only once but also at least 10 times.
Furthermore, in the present invention, being bendable means that even if the bent portion as described above is formed in a region including through holes that electrically connect the metal foils disposed on both sides of the circuit board, the conduction is not caused. This means that it is not hindered, that is, the increase in electrical resistance between the metal foils is suppressed.
Specifically, the bending property is evaluated by repeating a predetermined number of times after performing bending of 180 degrees with a bending radius of 0.5 mm using a mandrel tester and recovery thereof after measuring the resistance value between the metal foils. .

The circuit board in the present invention includes a first insulating layer and a circuit layer made of a metal foil having a thickness of 1 to 35 μm and disposed on both surfaces of the first insulating layer.
The first insulating layer is obtained by heating and pressure-molding a prepreg containing a base material and a first thermosetting resin composition, or a prepreg laminate obtained by laminating a predetermined number of the prepregs. It is preferable that the resin cured product is included.
There is no restriction | limiting in particular in the number of prepregs which comprises a prepreg laminated body, For example, it can select suitably so that the layer thickness of a 1st insulating layer may become desired thickness.

The prepreg in the present invention has a base material and a first thermosetting resin composition, and is obtained by impregnating the base material with the first thermosetting resin composition and drying it as necessary. It is preferable that
Although it will not restrict | limit especially if it is a glass cloth and a glass nonwoven fabric as a said base material, From a foldable viewpoint, it is preferable that it is a glass nonwoven fabric. The thickness of the substrate is not particularly limited, and can be, for example, 100 μm or less. Preferably it is 30 micrometers or less, More preferably, they are 13 micrometers or more and 30 micrometers or less. Bending characteristics are further improved by the thickness of the base material.

The first thermosetting resin composition includes at least one thermosetting resin and at least one curing agent, and further includes a curing accelerator and an organic solvent as necessary. .
The thermosetting resin is not particularly limited. Specifically, for example, epoxy resins, polyimide resins, polyamideimide resins, triazine resins, phenol resins, melamine resins, polyester resins, cyanate ester resins, acrylic resins, and modified products of these resins (for example, acrylic glycidyl resins, etc.) Can be mentioned.

  The first thermosetting resin composition in the present invention is a thermosetting resin selected from acrylic glycidyl resin and polyamideimide resin (hereinafter referred to as “first specific thermosetting resin”) from the viewpoint of bendability and heat resistance. It is preferable to include at least one of thermosetting resins selected from acrylic glycidyl resins and polyamideimide resins.

The acrylic glycidyl resin is not particularly limited as long as it is an acrylic resin containing a structural unit derived from glycidyl (meth) acrylate. Especially, it is preferable that the content rate of the structural unit derived from glycidyl (meth) acrylate is 1-30 mass%. Moreover, it does not restrict | limit especially about structural monomers other than glycidyl (meth) acrylate.
Specific examples include HTR-860P3 (manufactured by Nagase ChemteX Corporation).

  Any polyamideimide resin may be used as long as it has an amideimide skeleton. Among them, a modified polyamideimide resin is preferable, and a siloxane modified polyamideimide resin is more preferable.

The first thermosetting resin composition in the present invention preferably further includes another thermosetting resin in addition to the first specific thermosetting resin. Examples of the other thermosetting resin include an epoxy resin, a polyimide resin, a phenol resin, and a silicone resin. From the viewpoint of heat resistance and adhesiveness, an epoxy resin and a phenol resin are preferable.
Moreover, these other thermosetting resins may be used alone or in combination of two or more.

There is no restriction | limiting in particular in the weight average molecular weight of the said thermosetting resin, For example, it can be set as 10000-15500. At least one of the thermosetting resins contained in the first thermosetting resin composition preferably has a weight average molecular weight of 10,000 to 1,500,000, and preferably 30,000 to 1,000,000. More preferably, it is 000.
Bendability improves more because a weight average molecular weight is 10,000 or more. Moreover, it is suppressed that the impregnation property to a base material falls by a weight average molecular weight being 1500,000 or less, and it is suppressed that heat resistance and a bendability fall.

Although there is no restriction | limiting in particular as content rate of the 1st specific thermosetting resin which may be contained in a said 1st thermosetting resin composition, From a bendable viewpoint, the 1st thermosetting resin composition. It is preferable that it is 10-100 mass% with respect to solid content of, and it is more preferable that it is 10-80 mass%.
In addition, solid content of a thermosetting resin composition means components other than a volatile component from a thermosetting resin composition.

There is no restriction | limiting in particular as content rate of the thermosetting resin in a 1st thermosetting resin composition, For example, it can be set to 20-90 mass%, and it is preferable that it is 50-90 mass%. Bending property improves more by including 20 mass% or more of thermosetting resins with respect to solid content of the 1st thermosetting resin composition. Moreover, the fall of the impregnation property to the base material of a resin composition can be suppressed because it is 90 mass% or less.
In addition, the content rate of a thermosetting resin here is the thermosetting in a 1st thermosetting resin composition, when the 1st thermosetting resin composition contains 2 or more types of thermosetting resins. It is determined using the total amount of the functional resin.

  The first thermosetting resin composition in the present invention has a weight average molecular weight of 10,000 to 1,500,000, and is selected from an acrylic glycidyl resin and a polyamide-imide resin from the viewpoint of bendability and adhesiveness. It contains at least one kind of thermosetting resin, its content is preferably 10 to 80% by mass with respect to the solid content of the first thermosetting resin composition, and the weight average molecular weight is 10,000 to 15 At least one thermosetting resin selected from an acrylic glycidyl resin and a polyamideimide resin and at least one epoxy resin, and at least one selected from an acrylic glycidyl resin and a polyamideimide resin The content of the thermosetting resin is 10 to 50% by mass with respect to the solid content of the first thermosetting resin composition. More preferable.

Various conventionally known curing agents can be used as the curing agent. For example, when an epoxy resin is used as the thermosetting resin, polyfunctional phenols such as dicyandiamide, diaminodiphenylmethane, diaminodiphenylsulfone, phthalic anhydride, pyromellitic anhydride, bisphenol A, phenol novolac and cresol novolac, and bromine thereof And the like.
Although it does not restrict | limit especially as content rate of the hardening | curing agent in a said 1st thermosetting resin composition, It is preferable that it is 3-50 mass% with respect to a thermosetting resin, and it is 10-40 mass%. Is more preferable.

The first thermosetting resin composition may contain at least one accelerator for the purpose of promoting the reaction between the thermosetting resin and the curing agent. There are no particular limitations on the type and amount of the accelerator. Specific examples of the accelerator include, for example, imidazole compounds, organic phosphorus compounds, tertiary amines, quaternary ammonium salts, and the like. These may be used alone or in combination of two or more. Good.
Although it does not restrict | limit especially as content rate of the accelerator in a said 1st thermosetting resin composition, It is preferable that it is 0.0001-10 mass% with respect to a thermosetting resin, 0.001-1. More preferably, it is 00 mass%.

The first thermosetting resin composition may contain an organic solvent as necessary. Examples of the organic solvent include alcohol-based, ether-based, ketone-based, amide-based, aromatic hydrocarbon-based, ester-based, and nitrile-based solvents. It may be used as
The content of the organic solvent in the first thermosetting resin composition is not particularly limited, and can be appropriately selected according to the viscosity, impregnation property, and the like of the first thermosetting resin composition.

  Furthermore, the 1st thermosetting resin composition in this invention may further contain additives, such as a flame retardant, a flow control agent, a coupling material, and antioxidant, as needed. As these additives, commonly used components can be used without particular limitation.

  Although there is no restriction | limiting in particular in the impregnation amount of the 1st thermosetting resin composition in the said prepreg, From a viewpoint of bendability, heat resistance, and adhesiveness, the thermosetting resin with respect to the total mass of a base material and a thermosetting resin. It is preferable that it is 30-90 mass%, and it is more preferable that it is 35-65 mass%.

There is no restriction | limiting in particular as the layer thickness of a said 1st insulating layer, According to the objective, it can select suitably. For example, the thickness may be 3 μm to 200 μm, and is preferably 5 μm to 100 μm from the viewpoint of bendability.
In the first insulating layer, for example, by heating / pressing the prepreg or the prepreg laminate, the components in the first thermosetting composition contained in the prepreg react to form a resin cured product. Can be obtained. Details of this manufacturing method will be described later.

The metal foil disposed on both sides of the first insulating layer is not particularly limited, such as a gold foil, a copper foil, and an aluminum foil, but a copper foil is generally used.
The thickness of the metal foil is not particularly limited as long as it is 1 μm to 35 μm, but the bendability is further improved by using a metal foil of 3 to 18 μm.
Here, it is assumed that the thickness of the metal foil does not include the thickness of the plating layer formed when the plating process is performed at the time of forming a through hole to be described later.
Further, as a metal foil, a composite foil having a three-layer structure in which nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. are used as an intermediate layer, and copper layers are provided on both sides thereof, or A two-layer composite foil in which aluminum and copper foil are combined can also be used.

The metal foil in the present invention constitutes a circuit layer. A method for forming the circuit layer from the metal foil will be described later. The shape of the circuit is appropriately selected as necessary.
In addition, although a circuit layer consists of metal foil, the plating layer formed when a plating process is performed in the case of through-hole formation mentioned later shall also comprise a part of circuit layer.

The circuit board according to the present invention is provided with a through hole penetrating the first insulating layer. The through hole may be a through hole that electrically connects circuit layers made of metal foil provided on both sides of the circuit board to each other, or may be a through hole provided in a region not having the metal foil. Good.
The through hole can be formed, for example, by forming the through hole on the metal foil-clad laminate by a commonly used method such as drilling or laser processing and then plating the through hole.

There is no restriction | limiting in particular about the diameter of a through hole, It can select suitably as needed, for example, can be 25 micrometers-10 mm, and it is preferable that they are 25 micrometers or more and 1000 micrometers or less. The number of through holes is not particularly limited, and can be appropriately selected as necessary. Furthermore, it is preferable that the wall distance between the two through holes is 50 μm or more.
Further, the thickness of the plating layer formed by the plating treatment is not particularly limited, but may be, for example, 1 μm to 20 μm, and preferably 5 μm to 15 μm. The thickness of the circuit layer in the present invention includes the thickness of the plating layer in addition to the thickness of the metal foil. The thickness of the circuit layer can be, for example, 2 to 55 μm, and preferably 4 to 38 μm.

In the present invention, on the at least one surface of the circuit board, the second heat containing a thermosetting resin having a thickness of 80 μm or less and selected from an acrylic glycidyl resin and a polyamideimide resin. A second insulating layer containing a cured resin derived from the curable resin composition is provided. In the present invention, the thickness of the second insulating layer is 80 μm or less, but is preferably 5 to 80 μm and more preferably 7 to 60 μm from the viewpoint of bendability and heat resistance.
By providing the second insulating layer containing a specific thermosetting resin and having a specific thickness, the bendability of the multilayer printed wiring board is improved.

  The second insulating layer may be provided on only one surface of the circuit board or may be provided on both surfaces. Further, the second insulating layer may be provided on the entire surface of the circuit board or may be provided only in a part of the region.

The second insulating layer contains a second thermosetting resin selected from acrylic glycidyl resin and polyamide-imide resin (hereinafter sometimes referred to as “second specific thermosetting resin”). It contains at least one resin cured product derived from the thermosetting resin composition.
Although it does not restrict | limit especially as a weight average molecular weight of a said 2nd specific thermosetting resin, It is preferable that it is 10,000-1,500,000 from a viewpoint of bendability, 30,000-1,000,000. It is more preferable that

The second thermosetting resin composition preferably further includes a thermosetting resin other than the acrylic glycidyl resin and the polyamideimide resin. Examples of other thermosetting resins include, for example, epoxy resins, polyimide resins, phenol resins, silicone resins, etc. From the viewpoint of heat resistance, epoxy resins, phenol resins, etc. It is preferable that
Moreover, these other thermosetting resins may be used alone or in combination of two or more.

  Although there is no restriction | limiting in particular as content rate of the 2nd specific thermosetting resin contained in a said 2nd thermosetting resin composition, From a bendable viewpoint, solid content of the 2nd thermosetting resin composition It is preferable that it is 33.0-99.0 mass% with respect to it, and it is more preferable that it is 40.0-70.0 mass%.

  Further, the second thermosetting resin composition may further contain additives such as a curing agent, an accelerator, an organic solvent, a flame retardant, a flow regulator, a coupling material, and an antioxidant as necessary. Good. These details are the same as those of the first thermosetting resin composition described above, and the preferred embodiments are also the same.

  In the present invention, the second thermosetting resin composition and the first thermosetting resin composition may have the same resin composition or different resin compositions. . It is preferable that the 1st thermosetting resin composition and 2nd thermosetting resin composition in this invention have the same resin composition from a viewpoint of deformation | transformation suppression, such as bendability and curvature.

  The 2nd insulating layer in this invention can be formed by forming the layer which consists of a 2nd thermosetting resin composition on the said circuit board, and heating and pressurizing this, for example. Details of the method for forming the second insulating layer will be described later.

The second insulating layer in the present invention preferably has a metal foil on the surface opposite to the surface facing the circuit board. The metal foil provided on the second insulating layer is not particularly limited, such as a gold foil, a copper foil, and an aluminum foil, but a copper foil is generally used.
There is no restriction | limiting in particular in the thickness of the said metal foil, For example, it is preferable that it is 3-18 micrometers which can be 1 micrometer-35 micrometers from a bendability viewpoint.
Further, as a metal foil, a composite foil having a three-layer structure in which nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. are used as an intermediate layer, and copper layers are provided on both sides thereof, or A two-layer composite foil in which aluminum and copper foil are combined can also be used.

  In the multilayer printed wiring board of the present invention, the metal foil provided on the second insulating layer may form a circuit layer. Further, an insulating layer, an insulating layer and a metal foil (preferably a circuit layer) may be further provided on the metal foil provided on the second insulating layer, and provided on the second insulating layer. Two or more insulating layers and metal foils provided on the metal foil may be further laminated.

The multilayer printed wiring board of the present invention includes a bent portion in which at least one of a through hole and a non-penetrating via penetrating all layers is provided in a region where the circuit board and the second insulating layer are laminated.
The through hole penetrating all the layers may be any hole that penetrates all the layers and electrically connects at least two circuit layers to each other. The through hole penetrating all layers can be formed in the same manner as the through hole in the circuit board described above.
Further, the diameter and quantity of the through holes and the wall interval of the through holes are the same as those of the through holes in the circuit board described above, and the preferred embodiments are also the same.

The non-penetrating via penetrates at least one of the first insulating layer or the second insulating layer and conducts and connects at least two circuit layers, and must penetrate all the layers. There are no particular restrictions.
For example, even if the circuit layers provided on both sides of the circuit board are conductively connected, the circuit layer on one side of the circuit board and the circuit layer on the second insulating layer provided thereon are connected. Conductive connection may be used.

  The non-through hole is formed by, for example, plating the non-through hole after forming the non-through hole in the first insulating layer or the second insulating layer by a commonly used method such as drilling or laser processing. Can be formed.

The diameter of the non-through via is not particularly limited and may be appropriately selected as necessary. From the viewpoint of bendability, it is preferably 25 μm or more and 200 μm or less, and more preferably 25 μm or more and 100 μm or less. . Further, from the viewpoint of bendability, the ratio of the diameter of the non-through via to the depth of the non-through via is preferably 0.025 or more and 15.0 or less, more preferably 0.1 or more and 5.0 or less. preferable.
The number of non-through vias is not particularly limited, and can be appropriately selected as necessary. Further, it is preferable that the wall interval between the two non-through vias is 50 μm or more.

The multilayer printed wiring board of the present invention preferably has four or more circuit layers, and more preferably has a through hole penetrating all layers.
In the multilayer printed wiring board of the present invention, the multilayer printed wiring board having four or more circuit layers is formed by providing two or more second insulating layers having metal foil on one surface of the circuit board. In addition, one or more second insulating layers each having a metal foil may be provided on both sides of the circuit board. In the present invention, from the viewpoint of production efficiency, it is preferable that one or more second insulating layers each having a metal foil on the surface are provided on both surfaces of the circuit board.

  In the present invention, since the circuit board and the second insulating layer are in the above-described manner, even if a bent portion is formed in a region where four or more circuit layers, a through-hole penetrating all the layers, etc. are provided, It is suppressed that the conductivity between the circuit layers connected by through holes or the like is impaired.

<Manufacturing method of multilayer printed wiring board>
The manufacturing method of the multilayer printed wiring board of this invention has the thickness arrange | positioned on both surfaces of the 1st insulating layer containing the resin cured material derived from the 1st thermosetting resin composition, and the said 1st insulating layer. Forming a through hole penetrating the first insulating layer and a circuit layer made of the metal foil on a metal foil-clad laminate having a metal foil of 1 to 35 μm to obtain a circuit board; Derived from the second thermosetting resin composition containing at least one thermosetting resin selected from glycidyl acrylate resin and polyamideimide resin on at least one surface of the circuit board on which the circuit layer is formed. A step of providing a second insulating layer containing a cured resin and having a thickness of 80 μm or less; a step of processing a metal foil on the second insulating layer; and the circuit board and the second insulating layer, Stacked territory And a step of providing a bent portion providing a through hole and a non-penetrating via penetrating the entire layer in the region.
A multilayer printed wiring board manufactured by such a manufacturing method has excellent bendability even in a region provided with a through hole or a non-through via, and a resistance value between circuit layers connected through the through hole or the non-through via. Rise is suppressed.

The method of providing a through hole in the circuit board may include a step of drilling and a step of plating. Drilling is not particularly limited, and ordinary mechanical drills and laser machining are mainly used. The plating treatment may be either electroless plating or electroplating.
The preferred embodiment of the through hole is as described above.

  The method for forming the circuit layer is not particularly limited, and a commonly used circuit forming method can be appropriately selected and used. For example, a circuit layer made of a metal foil can be formed by using a normal photolithography method.

In the method for producing a multilayer printed wiring board of the present invention, the metal foil-clad laminate is a prepreg obtained by impregnating a glass woven fabric or glass nonwoven fabric with a first thermosetting resin composition, or the prepreg is predetermined. It can be obtained by a production method including a step of heating and pressurizing a prepreg laminate in which a plurality of layers are laminated and a metal foil disposed on both surfaces of the prepreg or the prepreg laminate to obtain a metal foil-clad laminate. preferable.
By heating and pressurizing the prepreg or prepreg laminate containing the first thermosetting composition, the components in the first thermosetting composition react to form a resin cured product, and the first insulation A layer is formed.

The heating temperature and pressure are not particularly limited, but the heating temperature can usually be 80 ° C to 250 ° C, preferably 130 ° C to 230 ° C. The pressure can be usually 0.5 MPa to 8.0 MPa, and preferably 1.5 MPa to 5.0 MPa.
For heating and pressurization, for example, a vacuum press is suitably used.

  In addition, the prepreg is a process comprising a step of impregnating a glass woven fabric or a glass nonwoven fabric (hereinafter sometimes simply referred to as “base material”) with the first thermosetting resin composition, and a drying step as necessary. It is preferable to obtain by a method. The details of the glass woven fabric and glass nonwoven fabric as the base material constituting the prepreg and the first thermosetting resin composition are as described above, and the preferred embodiments are also the same.

  As a method of impregnating the substrate with the first thermosetting resin composition, a commonly used impregnation method can be used without particular limitation, and examples thereof include a method of applying with a coating machine.

  The first thermosetting resin composition can be impregnated into the base material as a resin varnish. In the present invention, when the second thermosetting resin composition contains an organic solvent, the prepreg obtained may contain an organic solvent, but the organic solvent contained in the second thermosetting resin composition It is preferable that 80% or more is removed. The removal of the organic solvent can be performed by heating, for example, and is preferably heated at 80 to 180 ° C. The drying time by heating is not particularly limited and can be appropriately selected according to the purpose.

Although there is no restriction | limiting in particular in the thickness of the prepreg in this invention, It is preferable that it is 15 micrometers-200 micrometers from a viewpoint of bendability, and it is more preferable that it is 15 micrometers-100 micrometers.
Moreover, there is no restriction | limiting in particular in the number of prepregs which comprises a prepreg laminated body, Although it can select suitably so that it may become desired thickness, it is preferable that it is 1-5 sheets.

  The details of the metal foil disposed on both surfaces of the prepreg or prepreg laminate are the same as the metal foil in the circuit board, and the preferred embodiments are also the same.

In the method for producing a multilayer printed wiring board according to the present invention, at least one of thermosetting resins selected from a glycidyl acrylate resin and a polyamideimide resin is provided on at least one surface of a circuit board on which the through holes and the circuit layer are formed. Including a step of providing a second insulating layer having a thickness of 80 μm or less, including a cured resin derived from the second thermosetting resin composition containing seeds.
The step of providing the second insulating layer in the present invention preferably further includes the step of providing a metal foil on the surface of the second insulating layer opposite to the surface facing the circuit board. That is, the step of providing the second insulating layer in the present invention is preferably a step of providing a second insulating layer having a metal foil on the surface thereof on the circuit board.
The details of the metal foil are as described above.

  As a method of providing the second insulating layer having a metal foil on the surface on at least one surface of the circuit board, a layer made of the second thermosetting resin composition (hereinafter, “ A second thermosetting resin composition layer ”, a step of disposing a metal foil on the second thermosetting resin composition layer, and the circuit board and the metal foil. A first method including a step of heating and pressurizing the provided second thermosetting resin composition layer, and a resin-coated metal foil obtained from the second resin composition on a circuit board on a resin surface There may be mentioned a second method including a step of placing the circuit board in contact with the circuit board and a step of heating and pressurizing the circuit board on which the metal foil with resin is placed.

  In the first method, as a method of forming the second thermosetting resin composition layer on the circuit board, for example, the second thermosetting resin composition is applied onto the circuit board by a coating method or the like. And a method of forming a second thermosetting resin composition layer, a method of attaching a resin film containing the second thermosetting resin composition on a circuit board, and the like.

The second thermosetting resin composition used here is as described above.
As a method for applying the second thermosetting resin composition, any known application method can be used without particular limitation as long as the thickness of the formed second insulating layer can be 80 μm or less. be able to. Specific examples include methods such as comma coating, die coating, lip coating, and gravure coating. As a coating method for forming a resin layer with a predetermined thickness, a comma coating method in which an object to be coated is passed between gaps, a die coating method in which a resin varnish whose flow rate is adjusted from a nozzle, or the like can be applied. .

  In the second thermosetting resin composition layer formed on the circuit board, 80% by mass or more of the organic solvent contained in the second thermosetting resin composition used for coating is removed. preferable. As drying conditions for removing the organic solvent, for example, the drying temperature can be about 80 to 180 ° C. The drying time is not particularly limited.

  Moreover, the resin film containing a 2nd thermosetting resin composition apply | coats the said 2nd thermosetting resin composition on a mold release base material, for example, removes a mold release base material after drying. Can be manufactured. The release substrate is not particularly limited as long as it can withstand the temperature during drying, and a polyethylene terephthalate film with a release agent, a polyimide film, an aramid film, and an aluminum foil with a release agent that are generally used. A metal foil such as can be used.

The method similar to the coating method mentioned above can be used for application | coating to the mold release base material of a 2nd thermosetting resin composition. The drying temperature is about 80 ° C. to 180 ° C., and the drying time can be determined in consideration of the gelation time of the second thermosetting resin composition, and is not particularly limited. The coating amount of the second thermosetting resin composition is preferably applied such that the thickness of the resulting resin film is 80 μm or less, and more preferably 30 μm to 80 μm.
The details of the metal foil in the first method are the same as those described above, and the preferred embodiments are also the same.

While heating and pressurizing the circuit board provided with the second thermosetting resin composition layer and the metal foil, the components in the second thermosetting composition react to form a resin cured product, A second insulating layer having a metal foil on the surface is formed.
The heating temperature and pressure are not particularly limited, but the heating temperature can usually be 80 ° C to 250 ° C, preferably 130 ° C to 230 ° C. Moreover, a pressure can be normally 0.5 MPa-8.0 MPa, and it is preferable that it is 1.5 MPa-5.0 MPa.
For heating and pressurization, for example, a vacuum press is suitably used.

The resin-attached metal foil in the second method includes a metal foil and a resin layer formed on the metal foil using a second thermosetting resin composition.
The details of the metal foil and the second thermosetting resin composition are as described above.
The metal foil with resin can be produced by forming a resin layer by applying and drying the second thermosetting resin composition on the metal foil. Application and drying can be carried out in the same manner as the above-described application method and drying method.

By heating and pressurizing the circuit board on which the resin-attached metal foil is provided, the second insulating layer having the metal foil on the surface is formed.
About the temperature and pressure to heat, it is the same as that of the said 1st method.

In the production method of the present invention, the first thermosetting resin composition forming the first insulating layer and the second thermosetting resin composition forming the second insulating layer have the same resin composition. Even if it has, it may have a different resin composition. The first thermosetting resin composition and the second thermosetting resin composition preferably have the same resin composition from the viewpoint of suppressing deformation such as bendability and warpage.
In the present invention, when forming the second insulating layer, the through hole provided in the circuit board is filled with the second thermosetting resin composition forming the second insulating layer. preferable. Thereby, bendability improves more.

In the manufacturing method of the multilayer printed wiring board of this invention, it is preferable to include the process of carrying out circuit processing of the metal foil provided on the 2nd insulating layer.
The method for processing the metal foil is not particularly limited, and a commonly used circuit forming method can be appropriately selected and used. For example, a circuit layer made of a metal foil can be formed by using a normal photolithography method.

The present invention may further include a step of providing a through hole or a non-through via that electrically connects the circuit layer on the second insulating layer and the circuit layer on the first insulating layer.
The step of providing a through hole includes a step of providing a through hole and a step of plating the through hole. The step of providing the non-through hole includes a step of providing a non-through hole in the second insulating layer and a step of plating the non-through hole.
The through hole and the non-through hole can be provided by a commonly used method such as mechanical drilling or laser processing. The plating process may be an electroless plating process or an electrolytic plating process.

The method for manufacturing a multilayer printed wiring board according to the present invention includes a step of providing a bent portion in a region where the circuit board and the second insulating layer are laminated.
Details of the bent portion in the present invention are as described above. Moreover, as a method of providing the bent portion, a method that is usually used can be applied without particular limitation.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass. Of the following examples, Examples 6 and 8 are reference examples.

<Example 1>
Each component of the thermosetting resin composition shown below was mixed and diluted to 30% resin solids using methyl ethyl ketone to prepare a thermosetting resin varnish.
Acrylic resin composition: 80 parts (Glycidyl acrylate resin; HTR-860P3 (manufactured by Nagase ChemteX Corporation)
・ Epoxy resin: 40 parts (DER-331L (manufactured by Dow Chemical Co., Ltd.))
・ Novolak phenol resin: 40 parts (VP 6371 (manufactured by Hitachi Chemical Co., Ltd.))
・ Imidazole: 0.4 parts (2PZ-CN (Shikoku Chemicals Co., Ltd.))

The thermosetting resin varnish obtained above was impregnated into a glass cloth having a thickness of about 20 μm, and then heated and dried at 140 ° C. for 5 to 10 minutes to obtain a prepreg having a resin content of 75%.
Double-sided copper-clad laminates with a thickness of 50 μm are obtained by superimposing copper foils with a thickness of 12 μm on both sides of the prepreg and heating and pressing them at 170 ° C. for 90 minutes and 4.0 MPa press conditions. Was made.
The obtained double-sided copper-clad laminate was formed with through holes in a matrix (lattice) pattern with a pitch of 1.2 mm using a drill of Φ = 0.2 mm, and then subjected to through-hole plating by electroless plating. The plating thickness was 15 μm. A pad serving as a reference point and a daisy chain pattern circuit were formed in rows at the ends of the double-sided copper-clad laminate by etching to obtain a circuit board with through holes serving as an inner layer board.

The thermosetting resin varnish obtained above was cast into a copper foil having a thickness of 18 μm, and then heated and dried at 140 ° C. for 5 to 10 minutes to prepare a semi-cured copper foil with resin having a resin layer thickness of 40 μm.
3. Adhere the resin layer side of the semi-cured resin-coated copper foil toward the inner printed wiring side with through-holes on both sides of the circuit board with through-holes produced above, 170 ° C., 90 minutes, A simulated substrate having a thickness of 134 μm was produced by heating and pressing under press conditions of 0 MPa.
Using a drill with a diameter of 0.2 mm on the simulated substrate obtained, through holes were formed in a matrix (lattice) pattern with a pitch of 1.2 mm between the through holes of the circuit board with through holes, and then through the electroless plating process. Hole plating was performed. The plating thickness was 15 μm. A daisy chain pattern circuit is formed in a row by etching in the direction parallel to the direction of the daisy chain circuit of the circuit board with a pad and a through hole serving as a reference point at the end of this double-sided copper-clad laminate, and a multi-layer printing of 164 μm thickness A wiring board was obtained.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 36 μm.

(Evaluation)
A schematic plan view of the multilayer printed wiring board 300 obtained above is shown in FIG. 2, and a schematic cross-sectional view thereof is shown in FIG. On the multilayer printed wiring board, daisy chain pattern circuit rows of non-through vias 34 and daisy chain pattern circuit rows of through holes 32 penetrating all layers are alternately arranged. A pad portion 36 for resistance measurement of the daisy chain pattern circuit is provided at the end of the multilayer printed wiring board. When forming the multilayer printed wiring board, the pad portion 38 of the daisy chain pattern circuit of the non-penetrating via is once covered with the second insulating resin composition. The second insulating resin composition covering the pad portion 38 of the daisy chain pattern circuit of the via was removed with sandpaper. The multi-layer printed wiring board thus obtained was evaluated for bendability of 180 degrees with a bend radius of 0.5 mm using a mandrel tester.
The test piece had a strip shape with a width of 10 mm, and a part having through holes in one horizontal row was used as a bent part. The number of times until the resistance value of one of the through-holes of the inner layer circuit or the through-holes of all layers was increased by 10% or more of the initial resistance value or disconnected was measured by repeating the bending of 180 degrees. The evaluation results are shown in Table 1.

<Example 2>
In Example 1, a multilayer printed wiring board having a thickness of 168 μm was produced in the same manner as in Example 1 except that the thermosetting resin composition was changed to the following resin composition, and evaluation was performed using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 38 μm.
The evaluation results are shown in Table 1.
(Resin composition)
-Acrylic resin composition: 250 parts (Glycidyl acrylate resin; HTR-860P3 (manufactured by Nagase ChemteX Corporation)
・ Epoxy resin: 40 parts (DER-331L (manufactured by Dow Chemical Co., Ltd.))
・ Novolak phenol resin: 40 parts (VP 6371 (manufactured by Hitachi Chemical Co., Ltd.))
・ Imidazole: 0.4 parts (2PZ-CN (Shikoku Chemicals Co., Ltd.))

<Example 3>
A multilayer printed wiring board having a thickness of 162 μm was prepared in the same manner as in Example 1 except that the thermosetting resin composition was changed to the following resin composition in Example 1, and evaluation was performed using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 35 μm.
The evaluation results are shown in Table 1.
(Resin composition)
Acrylic resin composition: 20 parts (Glycidyl acrylate resin; HTR-860P3 (manufactured by Nagase ChemteX Corporation)
・ Epoxy resin: 40 parts (DER-331L (manufactured by Dow Chemical Co., Ltd.))
・ Novolak phenol resin: 40 parts (VP 6371 (manufactured by Hitachi Chemical Co., Ltd.))
・ Imidazole: 0.4 parts (2PZ-CN (Shikoku Chemicals Co., Ltd.))

<Example 4>
In Example 1, a 166 μm thick multilayer printed wiring board was prepared in the same manner as in Example 1 except that the thermosetting resin composition was changed to the thermosetting resin composition prepared as follows. The evaluation was performed using.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 37 μm.
The evaluation results are shown in Table 1.
225 g of N-methylpyrrolidone (NMP) solution of a siloxane-modified polyamideimide resin having a weight average molecular weight of 28000 and 52 amide groups in one molecule (resin solid content 40%), and YDCN-500 (Toto Kasei Co., Ltd.) as an epoxy resin (Product name: Cresol novolac type epoxy resin, dimethylacetamide solution with 50% resin solid content) 20 g and 1.0 g of 2-ethyl-4-methylimidazole are mixed and stirred for about 1 hour until the resin is uniform. Then, it was allowed to stand at room temperature for 24 hours for defoaming to prepare a thermosetting resin composition varnish.

<Example 5>
In Example 1, a multilayer printed wiring board having a thickness of 168 μm was prepared in the same manner as in Example 1 except that the thermosetting resin composition was changed to the thermosetting resin composition prepared as follows. The evaluation was performed using.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 38 μm.
The evaluation results are shown in Table 1.
225 g of NMP solution of siloxane-modified polyamideimide resin having a weight average molecular weight of 30000 and 38 amide groups in one molecule (resin solid content: 40%) and DER331L (Dow Chemical Co., Ltd., bisphenol A type epoxy resin as epoxy resin) 20 g of a dimethylacetamide solution having a resin solid content of 50%) and 1.0 g of 2-ethyl-4-methylimidazole, and the mixture was stirred for about 1 hour until the resin became uniform, and then defoamed for 24 hours. The thermosetting resin composition varnish was prepared by standing at room temperature.

<Example 6>
The copper foil-side surfaces of the copper foil with carrier (copper foil thickness: 1 μm, carrier layer thickness: 18 μm) were superimposed on the surfaces on both sides of the prepreg produced in Example 1, respectively, at 170 ° C. After heating and pressurizing for 90 minutes under a 4.0 MPa press condition, the carrier layer was peeled off to prepare a double-sided copper clad laminate having a thickness of 28 μm.
The obtained double-sided copper-clad laminate was processed in the same manner as in Example 1 to obtain a circuit board with through holes.
Next, the thermosetting resin varnish produced in Example 1 was cast on the surface of the copper foil with carrier (copper foil thickness: 1 μm, carrier layer thickness: 18 μm) on the copper foil side, and then heated at 140 ° C. for 5 hours. It was dried by heating for 10 minutes to prepare a semi-cured resin-coated copper foil having a resin layer thickness of 25 μm.
Next, the resin layer side of the resin-coated copper foil is pasted on both sides of the circuit board with through-holes produced above, facing the circuit board side with through-holes, 170 ° C., 90 minutes, 4. The carrier layer was peeled off by heating and pressurizing under press conditions of 0 MPa, and then the same treatment as in Example 1 was performed to produce a simulated substrate having a thickness of 74 μm. Subsequent steps were carried out in the same manner as in Example 1 to obtain a 104 μm thick multilayer printed wiring board. Evaluation was performed using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 1 μm, and the thickness of the second insulating layer was 23 μm.
The evaluation results are shown in Table 1.

<Example 7>
A simulated substrate having a thickness of 186 μm was prepared in the same manner as in Example 1 except that a copper foil having a thickness of 18 μm was used and a copper foil with a resin having a thickness of 45 μm was used. A multilayer printed wiring board having a thickness of 174 μm was obtained in the same manner as in Example 1 except that the simulated substrate thus obtained was used. Evaluation was performed using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 18 μm, and the thickness of the second insulating layer was 41 μm.
The evaluation results are shown in Table 1.

<Example 8>
Example 1 except that a semi-cured resin-coated copper foil with a resin layer thickness of 75 μm (copper foil thickness; 18 μm) was used instead of the semi-cured resin-coated copper foil with a resin layer thickness of 40 μm. In the same manner, a simulated substrate having a thickness of 198 μm was produced. A multilayer printed wiring board having a thickness of 228 μm was obtained in the same manner as in Example 1 except that the simulated substrate thus obtained was used.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 68 μm.
The evaluation results are shown in Table 1.

<Comparative Example 1>
In Example 1, a multilayer printed wiring board having a thickness of 168 μm was prepared in the same manner as in Example 1 except that the thermosetting resin composition was changed to the thermosetting resin composition prepared as follows. The evaluation was performed using.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 12 μm, and the thickness of the second insulating layer was 38 μm.
The evaluation results are shown in Table 1.

A thermosetting resin varnish was prepared by diluting a thermosetting resin composition having a resin composition below with methyl ethyl ketone and propylene glycol monomethyl ether to a resin solid content of 70%.
(Resin composition)
Brominated bisphenol A type epoxy resin: 100 parts (epoxy equivalent: 530)
・ Dicyandiamide: 4 parts ・ Imidazole (2E4MZ, manufactured by Shikoku Kasei Co., Ltd.): 0.5 parts

<Comparative example 2>
Using a polyimide film (AX182518, polyimide thickness 25 μm, manufactured by Nippon Steel Chemical Co., Ltd.) having a 18 μm thick copper foil on both sides as a metal foil-clad laminate, through holes are formed in the same manner as in Example 1. Thus, a circuit board with a through hole was obtained. Next, a simulated substrate was prepared in the same manner as in Example 1 except that a 38 μm thick resin film formed from the composition prepared as follows was used as a resin film, and evaluation was performed using this. It was.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 18 μm, and the thickness of the second insulating layer was 25 μm.
The evaluation results are shown in Table 1.

(Resin composition)
Ethoxylated bisphenol A dimethacrylate: 30 parts TMCH: 50 parts (molar ratio of 2,2,4-trimethylhexamethylene-1,6-diisocyanate to 2-hydroxyethyl acrylate 1: 2 adduct, Hitachi Chemical (Manufactured by Kogyo Co., Ltd.)
・ Dicyandiamide: 1 part ・ N, N-dimethylformamide: 3 parts

<Comparative Example 3>
According to Japanese Patent Laid-Open No. 2006-93647, a methyl ethyl ketone dispersion (concentration 20%) of fine particle crosslinked rubber was prepared.
In the resin composition of Comparative Example 1, a resin film A was produced in the same manner as described above using a thermosetting resin varnish obtained by adding 100 parts by mass of a methyl ethyl ketone dispersion of fine particle crosslinked rubber.
In Comparative Example 2, a simulated substrate was prepared in the same manner except that the 38 μm thick resin film A obtained above was used as the resin film, and evaluation was performed using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 18 μm, and the thickness of the second insulating layer was 24 μm.
The evaluation results are shown in Table 1.

<Comparative example 4>
Copper foil-side surface of carrier-attached copper foil (copper foil thickness: 0.5 μm, carrier layer thickness: 18 μm) on both sides of the prepreg produced using the thermosetting resin varnish produced in Comparative Example 1 Except that the carrier layer was peeled off to produce a double-sided copper-clad laminate with a thickness of 27 μm after being heated and pressed under the pressing conditions of 170 ° C., 90 minutes and 4.0 MPa. A simulated substrate having a thickness of 119 μm was prepared by performing the same process as in Example 1, and in the subsequent steps, a multilayer printed wiring board having a thickness of 164 μm was obtained in the same manner as in Example 1. Evaluation was performed using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 0.5 μm, and the thickness of the second insulating layer was 36 μm.
The evaluation results are shown in Table 1.

<Comparative Example 5>
A copper foil having a thickness of 70 μm is laminated on both sides of the prepreg produced using the thermosetting resin varnish produced in Comparative Example 1 to produce a double-sided copper-clad laminate, and a circuit board with a through hole is produced. After the production, a multilayer printed wiring board having a thickness of 282 μm was obtained by performing the same treatment as in Example 1 except that a semi-cured resin-coated copper foil having a resin layer thickness of 100 μm (copper foil thickness; 18 μm) was used. Was made and evaluated using this.
In the obtained multilayer printed wiring board, the thickness of the metal foil provided on the first insulating layer was 70 μm, and the thickness of the second insulating layer was 95 μm.
The evaluation results are shown in Table 1.

  It can be seen from Table 1 that the multilayer printed wiring board of the present invention is excellent in bendability in a region having a through hole.

20 Through-hole 22 penetrating through metal foil-clad laminate Through-hole 24 penetrating through all layers Non-through via 26 Circuit layer 32 Through-hole 34 penetrating through all layers Non-through vias 36, 38 Pad portion 100 First insulating layer 200 Second insulating layer 300 Simulated substrate for evaluation

Claims (11)

A metal foil having a thickness of 3 μm to 18 μm disposed on both surfaces of the first insulating layer containing the resin cured product derived from the first thermosetting resin composition and the first insulating layer;
A circuit board formed with a through-hole penetrating the circuit layer made of the metal foil and the first insulating layer;
A resin cured product derived from a second thermosetting resin composition that is provided on at least one surface of the circuit board and includes at least one thermosetting resin selected from a glycidyl acrylate resin and a polyamideimide resin. And a second insulating layer having a thickness of 7 μm to 60 μm,
A multilayer printed wiring board comprising a bent portion in which at least one of a through hole and a non-penetrating via penetrating all layers is provided in a region where the circuit board and the second insulating layer are laminated.   2. The at least one of the first thermosetting resin composition and the second thermosetting resin composition includes at least one thermosetting resin having a weight average molecular weight of 10,000 to 1,000,000. Multilayer printed wiring board.   The multilayer printed wiring board according to claim 1 or 2, wherein the first thermosetting resin composition and the second thermosetting resin composition have the same resin composition.   The multilayer printed wiring board of any one of Claims 1-3 which has a metal foil on the surface on the opposite side to the surface facing the said circuit board of a said 2nd insulating layer.   The multilayer printed wiring board of any one of Claims 1-4 which has a 4 or more circuit layer.   The multilayer printed wiring board of any one of Claims 1-5 which has a through hole which penetrates all the layers. A metal foil tension having a first insulating layer containing a cured resin derived from the first thermosetting resin composition and a metal foil having a thickness of 3 μm to 18 μm disposed on both surfaces of the first insulating layer Forming a circuit layer comprising a through-hole penetrating the first insulating layer and the metal foil on the laminated plate to obtain a circuit board;
Second thermosetting resin composition containing at least one thermosetting resin selected from glycidyl acrylate resin and polyamideimide resin on at least one surface of the circuit board on which the through hole and the circuit layer are formed. A step of providing a second insulating layer including a cured resin derived from a product and having a thickness of 7 μm to 60 μm;
Providing a bent portion including at least one of a through hole and a non-through via penetrating all layers in a region where the circuit board and the second insulating layer are laminated;
A method for producing a multilayer printed wiring board comprising: A prepreg obtained by impregnating the first thermosetting resin composition into a glass woven fabric or glass nonwoven fabric having a thickness of 30 μm or less, or a prepreg laminate in which a predetermined number of the prepregs are laminated,
A metal foil having a thickness of 3 μm to 18 μm disposed on both sides of the prepreg or prepreg laminate;
The manufacturing method of the multilayer printed wiring board of Claim 7 which further includes the process of heating and pressurizing and obtaining a metal foil clad laminated board. The step of providing the second insulating layer includes providing a layer made of the second thermosetting resin composition on at least one surface of the circuit board on which the through hole and the circuit layer are formed. Placing a metal foil on the layer of the thermosetting resin composition of 2,
Forming a second insulating layer having a metal foil on the surface by heating and pressurizing the layer made of the second thermosetting resin composition and the metal foil; and
The manufacturing method of the multilayer printed wiring board of Claim 7 or Claim 8 containing this. The step of providing the second insulating layer includes a resin-coated metal foil obtained by using the second thermosetting resin composition on at least one surface of the circuit board on which the through hole and the circuit layer are formed. Placing the resin surface in contact with the circuit board;
Forming a second insulating layer having the metal foil on the surface by heating and pressurizing the metal foil with resin; and
The manufacturing method of the multilayer printed wiring board of Claim 7 or Claim 8 containing this. The manufacturing method of the multilayer printed wiring board of any one of Claims 7-10 whose said 1st thermosetting resin composition and 2nd thermosetting resin composition are the same resin compositions. Way .

Images