JP2005268518A - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board wherein an interface between metal to be formed with a circuit and substrate resin is smoothed, thereby obtaining excellent micro-circuit formability or high frequency characteristic. <P>SOLUTION: The wiring board contains the metal to be formed with a circuit and the substrate resin, and contains a resin layer which differs from the substrate resin between the metal and the substrate resin. The resin layer contains an amide group of 4 mol% or more. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wiring board including a resin layer different from a base material at an interface between a metal forming a circuit and the base material resin.

  The laminate for a printed wiring board is obtained by stacking a predetermined number of prepregs each having an electrically insulating resin composition as a matrix and then heating and pressing to integrate them. When a printed circuit is formed by a subtractive method, a metal-clad laminate is used. This metal-clad laminate is manufactured by stacking a metal foil on the surface (one side or both sides) of the prepreg and heating and pressing. Copper foil is mainly used as the metal foil, and thermosetting resins such as phenol resin, epoxy resin, polyimide resin, bismaleimide-triazine resin are used as the electrically insulating resin used for the metal-clad laminate. A thermoplastic resin such as a fluororesin or a polyphenylene ether resin is sometimes used.

  With the spread of information terminal devices such as personal computers and mobile phones, printed wiring boards are becoming smaller and higher in density. The mounting form has progressed from a pin insertion type to a surface mounting type and further to an area array type represented by BGA (ball grid array) using a plastic substrate. In a substrate on which a bare chip such as a BGA is directly mounted, the connection between the chip and the substrate is generally performed by wire bonding by thermosonic bonding. For this reason, the substrate on which the bare chip is mounted is exposed to a high temperature of 150 ° C. or higher. Therefore, a certain amount of heat resistance is required for the above-mentioned electrically insulating resin.

  In addition, the conductor circuit is generally formed by a subtractive method in which an unnecessary portion of a metal foil is removed by etching, or a semi-additive method in which a resist is formed on a thin metal layer and a conductor is formed by plating ( For example, Patent Document 1), in any case, there is a process of finally removing unnecessary metal. At that time, the anchor part of the roughened surface tends to remain on the base resin, and it takes time to etch, and the short circuit of the anchor part caused by etching or the circuit width design on the upper and lower surfaces of the circuit Deviation from the value may occur. Therefore, there is a demand for excellent adhesion between the resin and the conductor circuit without relying on the anchor effect.

  Furthermore, magnetic lines of force are generated in the vicinity of the current in the conductor, but since the interference of the lines of magnetic force is greater at the center of the conductor, the current is concentrated at the periphery and corners. This is called the skin effect, and this tendency increases as the frequency increases. It is thought that the smoother the surface of the conductor, the more the increase in resistance due to the skin effect can be suppressed, but the adhesion of the conventional electrically insulating resin is largely due to the anchor effect on the rough surface, which is contrary to the high frequency signal. It has become a thing. For this reason, surface smoothness is required for circuit conductors as signal frequency increases.

From the above, not only is the heat resistance required for the insulating resin used in the prepreg, but an adhesive force higher than conventional is desired for bonding between the metal foil subjected to circuit formation and the electrically insulating resin, In order to produce thinner wiring, smoothness of the surface of the metal foil, that is, refinement of the roughened shape is also required.
Japanese Patent Laid-Open No. 11-186716

  The present invention eliminates the above-mentioned problems of the prior art and includes a resin layer different from a base resin excellent in heat resistance and adhesion to a metal or base material at the interface between the metal forming the circuit and the base resin. Thus, it is possible to provide a wiring board excellent in fine circuit formability and high frequency characteristics.

  The present invention relates to the following.

  (1) A wiring board comprising a resin layer different from a base material at at least one interface between a metal forming a circuit and the base material resin, and the resin layer different from the base material contains 4% by mass or more of amide groups.

  (2) The wiring board according to item (1), wherein the surface roughness of the metal forming the circuit in contact with the resin layer different from the base material is 3 μm or less in terms of 10-point average roughness.

  (3) The wiring board according to item (1), wherein the thickness of the resin layer different from that of the substrate is 10 μm or less.

  (4) The wiring board according to item (1), wherein the glass transition point (Tg) of the resin layer different from the substrate is 200 ° C. or higher.

  According to the wiring board of the present invention, heat resistance is excellent, and the adhesiveness between the resin layer and the metal forming the circuit is improved, which is advantageous for the formation of fine wiring and high-frequency signal transmission.

  Hereinafter, preferred embodiments of the present invention will be described.

  The conductor circuit is generally formed by a subtractive method in which unnecessary portions of the metal foil on the insulating material are removed by etching, or a semi-additive method in which a resist is formed on a thin metal layer on the insulating material and the conductor is formed by plating. There is a method, but in any event, there is a process of removing the unnecessary portion of the metal. At that time, the anchor portion of the roughened surface tends to remain, and it takes time for etching. In addition, a short circuit may occur due to the etching residue of the anchor portion, or the circuit width may deviate from the design value on the upper and lower surfaces of the circuit. May occur. Further, when the circuit is miniaturized, the contact area between the insulating material and the metal is reduced, so that unnecessary stress is generated in the process, and the metal foil is peeled off. Therefore, in order to bond a metal foil to be subjected to circuit formation and an insulating material, it is necessary to refine the roughened shape on the surface of the metal foil in order to produce a finer wiring as well as an adhesive force higher than that in the past.

  Magnetic field lines are generated in the vicinity of the current in the conductor, but since the interference of the magnetic field lines is greater at the center of the conductor, the current is concentrated at the periphery and corners. This is called the skin effect, and this tendency increases as the frequency increases. It is considered that the smaller the surface roughness of the conductor circuit, the more the resistance increase due to the skin effect can be suppressed, which is advantageous for the transmission of high-frequency signals.

  A copper foil can be used as the “metal forming the circuit”. When using copper foil, it is preferable to use copper foil with small surface roughness. When ten-point average roughness (Rz) is used as the surface roughness, Rz is preferably 3 μm or less, and more preferably 2 μm or less. Rz is the surface roughness calculated according to the definition of JIS B 0601, and is measured using, for example, a stylus type surface roughness measuring instrument.

  Copper foil can be used as either electrolytic copper foil or rolled copper foil, but in order to use an adhesive surface with a small surface roughness, it has not been subjected to a treatment to give fine irregularities to the surface such as a roughening treatment. preferable. Further, the glossy surface of the so-called electrolytic copper foil can be used as it is. When using the glossy surface of the copper foil, there is no particular limitation, and a commercially available copper foil can be used as it is. As commercially available copper foil, GTS, GTS-MP, GTS-FLP, GY, GY-MP, F-WS, TSTO, DT-GL, DT-GLD manufactured by Furukawa Circuit Foil Co., Ltd. There are SLP, YGP, 3EC-VLP manufactured by Mitsui Kinzoku Co., Ltd., but not limited thereto. The glossy surface of these commercially available copper foils is Rz = 1.5-2.0 μm.

  F2-WS (Furukawa Circuit Foil, Rz = 3.0 μm), 3EC-VLP (Mitsui Metals, Rz = 3.0 μm), etc. are available as copper foils with a small surface roughness. Further, as a commercially available copper foil having a very small surface roughness, F0-WS (Furukawa Circuit Foil Co., Ltd., Rz = 1.2 μm) can be used.

  There are various types of commercially available copper foils having thicknesses ranging from 10 to 150 μm, but 18 μm and 35 μm are mainly used as circuit board applications. In order to form a fine wiring pattern, it is more preferable to use a thin copper foil of 12 μm or 9 μm.

  Moreover, as "the metal which forms a circuit", metal foils, such as aluminum foil other than copper foil, can also be used, and it is preferable that thickness is 5-200 micrometers. Also, nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. between a copper foil layer having a thickness of 0.5-15 μm and a copper foil layer having a thickness of 10-300 μm A composite foil having a three-layer structure provided with an intermediate layer made of or a composite foil having a two-layer structure in which aluminum and copper foil are combined can also be used. In any case, the surface roughness of the metal foil is preferably Rz = 3.0 μm or less, and more preferably Rz = 2.0 μm or less.

  Next, the “resin layer different from the base resin”, that is, the resin layer provided at the interface between the metal forming the circuit and the base resin will be described.

  The “resin layer” in the present invention is different from the base resin and preferably has a thickness of 10 μm or less. By setting the thickness to 10 μm or less, the amount of resin required per unit area can be reduced, and the original properties of the base material are less likely to be impaired.

  The resin layer contains 4% by mass or more of amide groups. If the amide group is less than 4% by mass, the adhesive strength with the metal foil may be insufficient. The ratio of the amide group in the resin was calculated with the molecular weight of the amide group being 43.

  Examples of the resin containing an amide group include polyamide, polyamideimide, and nylon. Polyamideimide is preferably used from the viewpoint of heat resistance, and polyamide modified by siloxane from the viewpoint of reducing residual volatile content in the resin. More preferably, an imide is used. These resins may be used alone or in combination of several kinds.

  The resin containing an amide group is more preferably a thermosetting resin by mixing a compound containing an amide group and an amide reactive compound having a functional group that reacts with the amide group. Examples of the amide-reactive compound include polyfunctional epoxy resins, polyimide resins, unsaturated polyester resins, polyurethane resins, bismaleimide resins, triazine-bismaleimide resins, and phenol resins, and polyfunctional epoxy compounds are preferably used. By using a polyfunctional epoxy compound as the amide-reactive compound, not only the heat resistance of the resin layer but also the mechanical characteristics and electrical characteristics can be improved. Polyfunctional epoxy compounds include bisphenol A type epoxy resin, tetrabromobisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, Examples thereof include biphenyl novolac type epoxy resins and alicyclic epoxy resins. These resins may be used alone or in combination of several kinds. The compounding amount of the amide-reactive compound can be determined in such a range that the amount of amide groups in the resin layer is not less than 4% by mass.

  When a polyfunctional epoxy compound is used as the amide-reactive compound, it is preferable to further add a polyfunctional epoxy compound and an amide group reaction accelerator. Examples of the reaction accelerator include amines such as dicyandiamide, diaminodiphenylmethane, and guanylurea, alkyl group-substituted imidazoles such as 2-ethyl-4-methylimidazole, and imidazoles such as benzimidazole.

  The compounding amount of the reaction accelerator can be determined according to the epoxy equivalent in the polyfunctional epoxy compound. For example, when an amine compound is used as the reaction accelerator, the equivalent of the active hydrogen of the amine and the polyfunctional epoxy compound It is preferable to blend so that the epoxy equivalents are equal. Moreover, when using imidazole as a reaction accelerator, it is preferable that the compounding quantity of a reaction accelerator is 0.1-2.0 weight part with respect to 100 weight part of polyfunctional epoxy compounds. When the blending amount of these reaction accelerators is less than the above range, the polyfunctional epoxy compound is insufficiently cured, and the glass transition temperature after curing of the curable resin tends to decrease. There is a tendency that the electrical characteristics after curing of the curable resin are lowered by the agent. The resin layer preferably has a glass transition point (Tg) of 200 ° C. or higher. In a substrate on which a bare chip such as a BGA is directly mounted, the connection between the chip and the substrate is performed by wire bonding using thermosonic bonding, so that the substrate on which the bare chip is mounted is exposed to a high temperature. Therefore, the resin layer present at the interface between the metal foil and the base resin must be excellent in heat resistance, and the Tg is preferably 200 ° C. or higher. In addition, Tg of the said resin layer is measured using a dynamic viscoelasticity measuring apparatus (DVE).

  In the resin layer, a filler, a coupling agent, a flame retardant, and the like can be added as other components as long as the curing is not inhibited.

  Next, the prepreg used as a base material in the present invention will be described.

  The prepreg used in the present invention may be a prepreg made of a curable resin in a B stage state that does not contain reinforcing fibers, or a prepreg made of a curable resin in a B stage state in which reinforcing fibers are arranged. A prepreg made of a curable resin in a B-stage state in which reinforcing fibers are arranged is preferable.

  A prepreg made of a curable resin in a B-stage state in which no reinforcing fiber is arranged can be obtained by making the curable resin into a semi-cured state (B-stage) with a film shape, and B in which a reinforcing fiber is arranged A prepreg made of a curable resin in a stage state can be obtained by impregnating a curable resin into a reinforcing fiber and then making the impregnated resin into a semi-cured state (B stage). As the curable resin, it is preferable to use a thermosetting resin such as an epoxy resin, a polyimide resin, or a phenol resin. Examples of reinforcing fibers include glass fibers made of E glass, D glass, S glass, Q glass, and the like, organic fibers made of polyimide, polyester, tetrafluoroethylene, and the like, and fibers obtained by mixing these. These fibers can be used as reinforcing fibers in the form of, for example, woven fabric, non-woven fabric, roving, chopped strand mat, and surfacing mat.

  As the prepreg, a commercially available prepreg can be used, or a prepreg having a plurality of layers of prepreg may be used. Applicable commercially available prepregs include prepregs (GEA-67, GEA-679, GEA-679F, Hitachi Chemical Co., Ltd.) in which a glass cloth, which is a glass fiber woven fabric, is impregnated with a thermosetting resin mainly composed of an epoxy resin. Co., Ltd.), high frequency prepreg impregnated with low dielectric constant resin (GXA-67, manufactured by Hitachi Chemical Co., Ltd.), prepreg impregnated with glass cloth with resin composition in which thermosetting component is blended in polyimide (GEA) -I-671, manufactured by Hitachi Chemical Co., Ltd.).

  The blending ratio of the curable resin and the reinforcing fiber in the prepreg provided with the reinforcing fibers is preferably curable resin / reinforced fiber = 20/80 to 80/20, and 40/60 to 60/40 in weight ratio. It is more preferable.

  Formation of a resin layer different from the base resin in the present invention is a method in which a solution obtained by dissolving a resin in an organic solvent is directly applied to a metal foil to form a metal foil with resin, and a resin formed into a film by applying on a support. There are a method of forming a layer and a method of applying a solution in which a resin is dissolved in an organic solvent to a base material, but the method is not limited thereto.

  The method for forming a metal foil with a resin can be prepared by applying the resin solution to a predetermined surface of a copper foil using a coating machine and then drying by heating. As a coating method, a comma casting machine, a dip coating machine, a kiss coating machine, and a natural casting application can be used. Next, in order to obtain a laminated board with double-sided metal foil, several prepregs for forming a laminate are stacked so that the adhesive layer of the two metal foils with resin and the prepreg are combined, and the temperature is 0 at 160 ° C. to 250 ° C. It can be obtained by applying pressure of 0.1 to 8.0 MPa and heating and pressurizing for 10 minutes or more, preferably 30 minutes or more, more preferably 60 minutes or more. This step is more preferably performed under vacuum.

  A method of forming a resin layer into a film, that is, a method of forming a resin film can be produced by applying the resin solution onto a support using a coating machine and then drying by heating. As a coating method, a comma casting machine, a dip coating machine, a kiss coating machine, and a natural casting application can be used. Next, in order to obtain a laminated board with a double-sided metal foil, the produced resin film can be inserted between the metal foil and the base resin. As a method of inserting the prepared resin film between the metal foil and the base resin, after temporarily bonding together the above support so that the resin layer is in contact with the base material, the support is peeled off, and the metal is placed thereon. There are a method of laminating a foil and a method of peeling a support first and stacking it on a base material, and stacking a metal foil on the substrate and press laminating. In any method, the resin film and the metal foil are sequentially laminated on both surfaces of several prepregs for forming a laminate, and a pressure of 0.1 to 8.0 MPa is applied at 160 to 250 ° C. for 10 minutes or more, preferably A laminate with a double-sided metal foil can be obtained by heating and pressing for 30 minutes or more, more preferably 60 minutes or more. This step is more preferably performed under vacuum.

  The method of applying to the substrate is to laminate several prepregs for forming a laminate to form a substrate, and after applying the resin solution to the outermost prepreg surface, heat drying to form a resin layer. Also good. Thereafter, in order to obtain a laminated board with double-sided metal foil, the metal foil is overlaid on the applied resin layer, and a pressure of 0.1 to 8.0 MPa is applied at 160 to 250 ° C. for 10 minutes or more, preferably You may heat-press for 30 minutes or more, More preferably, 60 minutes or more. This step is more preferably performed under vacuum.

  The obtained metal-clad laminate has three layers of laminate-formed prepreg cured product, which is a cured product of the laminate-forming prepreg, as a central layer, and metal foils are laminated in this order via a resin layer on the upper and lower surfaces. It has the structure which was made.

  Furthermore, a predetermined wiring pattern can be formed on the metal foil to obtain a wiring board. In this metal-clad laminate, the metal foil is adhered to the prepreg cured product via the resin layer, and the metal foil is firmly adhered to the laminate in the metal-clad laminate, and the interface between the metal foil and the adhesive layer Therefore, it is possible to form a fine wiring pattern on the metal-clad laminate and reduce the transmission loss of high-frequency signals. Even in that case, peeling of the conductor layer made of the metal foil is extremely reduced.

  Hereinafter, the present invention will be specifically described with specific examples, but the present invention is not limited thereto.

(Production of varnish)
(Examples 1-2)
PAI-37 (trade name, manufactured by Hitachi Chemical Co., Ltd., polyamideimide resin, resin solid content 30 wt%, amide group 8.05 mass%) 63.3 g and epoxy resin DER-331L (trade name, manufactured by Dow Chemical Co., Ltd.) Bisphenol A type epoxy resin) 2.0 g (dimethylacetamide solution having a resin solid content of 50% by mass) and 0.02 g of 2-ethyl-4-methylimidazole were blended and stirred for about 1 hour until the resin became uniform. It left still at room temperature for 2 hours for defoaming, and it was set as the varnish of Example 1 (7.63 mass% of amide groups). Moreover, the case where an epoxy resin and imidazole were not added was made into the varnish of Example 2.

(Examples 3 to 4)
PAI-55 (trade name, manufactured by Hitachi Chemical Co., Ltd., polyamide imide resin, resin solid content 30% by weight, amide group 7.38% by mass) 63.3 g and epoxy resin DER-331L (trade name, manufactured by Dow Chemical Co., Ltd.) Bisphenol A type epoxy resin) 2.0 g (dimethylacetamide solution having a resin solid content of 50% by mass) and 0.02 g of 2-ethyl-4-methylimidazole were blended and stirred for about 1 hour until the resin became uniform. It left still at room temperature for 2 hours for defoaming, and it was set as the varnish (amide group 7.00 mass%). Moreover, the case where an epoxy resin and imidazole were not added was made into the varnish of Example 4.

(Comparative Example 1)
PAI-37 (trade name, manufactured by Hitachi Chemical Co., Ltd., polyamideimide resin, resin solid content 30% by weight, amide group 8.05% by mass) 26.7 g and epoxy resin DER-331L (trade name, manufactured by Dow Chemical Company, (Bisphenol A type epoxy resin) 24.0 g (dimethylacetamide solution having a resin solid content of 50% by mass) and 0.24 g of 2-ethyl-4-methylimidazole were mixed and stirred for about 1 hour until the resin became uniform. It left still at room temperature for 2 hours for defoaming, and it was set as the varnish (amide group 3.18 mass%).

(Comparative Example 2)
PAI-55 (trade name, manufactured by Hitachi Chemical Co., Ltd., polyamideimide resin, resin solid content 30 wt%, amide group 7.38 mass%) 26.7 g and epoxy resin DER-331L (trade name, manufactured by Dow Chemical Co., Ltd.) (Bisphenol A type epoxy resin) 24.0 g (dimethylacetamide solution having a resin solid content of 50% by mass) and 0.24 g of 2-ethyl-4-methylimidazole were mixed and stirred for about 1 hour until the resin became uniform. It left still at room temperature for 2 hours for defoaming, and it was set as the varnish (amide group 2.95 mass%).

(Formation of resin layer 1)
The varnishes produced in Examples 1 to 4 and Comparative Examples 1 to 2 were adjusted to a solid content of 7% by mass by adding dimethylacetamide, and then naturally cast on the glossy surface (Rz = 2 μm) of the electrolytic copper foil. The resin-coated copper foil was produced by drying at 160 ° C. for 10 minutes in a hot air circulation dryer. The thickness of the resin after drying was 2 to 3 μm. Let the copper clad laminated board produced using these be Examples 5-8 and Comparative Examples 4-5, respectively.

(Formation of resin layer 2)
The varnishes produced in Examples 1 to 4 and Comparative Examples 1 to 2 were applied onto a PET film, and dried in a warm air circulating drier at 160 ° C. for 10 minutes to form a film. The resin thickness after drying was 8 μm. Let the copper clad laminated board produced using these be Examples 9-12 and Comparative Examples 6-7, respectively.

(Formation of resin layer 3)
After adjusting the solid content to 7 mass% by adding dimethylacetamide to the varnishes produced in Examples 1-4 and Comparative Examples 1-2, one side of a low dielectric constant prepreg GXA-67N (manufactured by Hitachi Chemical Co., Ltd.) The film was naturally cast and then dried at 160 ° C. for 10 minutes in a hot air circulating dryer. The thickness of the resin after drying was 1 to 2 μm. Let the copper clad laminated board produced using these be Examples 13-16 and Comparative Examples 8-9, respectively.

(Method for producing copper-clad laminate)
Four sheets of low dielectric constant prepreg GXA-67N (manufactured by Hitachi Chemical Co., Ltd.) are used as a base material, and a resin layer and an electrolytic copper foil are stacked on both sides in that order at 230 ° C., 90 minutes, under a 3.0 MPa press condition. A double-sided copper clad laminate was produced. At this time, the glossy surface (Rz = 2 μm) of the electrolytic copper foil was in contact with the resin layer. Further, as Comparative Example 10, four low dielectric constant prepregs GXA-67N (manufactured by Hitachi Chemical Co., Ltd.) are stacked, and the glossy surface of the electrolytic copper foil (Rz = 2 μm) and the prepreg are stacked on both sides thereof, and 230 A double-sided copper-clad laminate was produced under the press conditions of 3.0 MPa at 90 ° C. for 90 minutes.

(Adhesion and moisture absorption heat resistance evaluation)
The copper foil peeling strength was measured by peeling the copper foil of the above copper-clad laminate at a rate of 5 mm width and 5 cm / min (90 ° peel test, conforming to JIS C 6481). Moreover, the copper foil peeling strength after leaving still for 2 hours (PCT process) at 121 degreeC and 100% RH constant temperature was measured similarly.

  In addition, the moisture absorption and heat resistance between the copper foil and the substrate was evaluated by cutting the copper-clad laminate into 5 mm squares, and etching the copper foil having a half area on both sides at 121 ° C. and 100% RH. After being allowed to stand in a constant temperature and humidity chamber for 2 hours, the presence or absence of blistering between the copper foil and the base material was evaluated when submerged in a solder bath at 260 ° C. for 20 seconds.

(Measurement of Tg of resin)
In Examples 1 to 4 and Comparative Examples 1 to 2, a varnish before solid content preparation or a resin solid content of 30% was applied onto a PET film, and dried in a hot air circulating dryer at 160 ° C. for 10 minutes. A resin film was prepared. The film was then further heated at 250 ° C. for 1 hour. This film was cut into a width of 5 mm, and Tg was measured using a dynamic viscoelasticity measuring apparatus (DVE) under the conditions of 20 mm between chucks, a temperature rising rate of 5 ° C./min, and a measurement range of 30 to 300 ° C.

(Evaluation results of adhesion and moisture absorption heat resistance)
The evaluation results are summarized in Table 1.

  Even if the adhesive surface of the copper foil was a glossy surface (Rz = 2 μm) level, in Examples 5 to 16, the adhesion to the substrate and the moisture absorption heat resistance were good. On the other hand, in Comparative Examples 4 to 9 in which the amount of amide groups was 4% by mass or less and Comparative Example 10 in which no resin layer was formed, the adhesion to the substrate and the moisture absorption heat resistance were insufficient.

(High-frequency signal transmission characteristics and fine circuit pattern formability)
A straight line was formed on the copper clad laminate of Example 7 by etching, and the loss when a signal in the frequency range of 0.1 to 10 GHz was transmitted was measured. Further, in the production of a copper-clad laminate, Comparative Example 11 was used when a copper foil having an adhesive surface Rz of 5.0 μm was used as the copper foil. The relationship between signal frequency and transmission loss is shown in FIG. The transmission loss was smaller in Example 7 where the Rz of the copper foil was 3 μm or less. The solid line shows Example 7 (Rz = 2.0 μm at the conductor / resin interface), and the broken line shows Comparative Example 11 (Rz = 5.0 μm at the conductor / resin interface).

  In addition, as a result of evaluating the fine circuit pattern formability of the copper-clad laminates of Examples 5 to 16 and Comparative Examples 4 to 11, in Examples 5 to 16, pattern formation of line / space = 20/20 μm is possible. However, in Comparative Examples 4 to 11, circuit peeling occurred. In Comparative Example 11, the circuit shape was trapezoidal, and a large deviation occurred in the design value.

5 is a graph showing the relationship between signal frequency and transmission loss.

Claims (4)

  A wiring board including a metal forming a circuit and a base resin, wherein the resin layer includes a resin layer different from the base resin between the metal and the base resin, and the resin layer has an amide group of 4% by mass or more. Including wiring board.   The wiring board according to claim 1, wherein the surface roughness of the metal in contact with the resin layer is 3 μm or less in terms of 10-point average roughness (Rz).   The wiring board according to claim 1, wherein the resin layer has a thickness of 10 μm or less.   The wiring board according to claim 1, wherein the resin layer has a glass transition point (Tg) of 200 ° C. or higher.

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