JP2006160899A - Manufacturing methods of electrically insulating substrate and wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a higher-density wiring board by inhibiting spreading of a through-hole filler such as a conductive paste and miniaturizing via holes/wires, to provide a thin electrically insulating substrate, and to provide a manufacturing method of a thin wiring board excellent in productivity. <P>SOLUTION: The electrically insulating substrate is formed by pasting a thermosetting resin onto a core through lamination, wherein the thermosetting resin is formed on a mold-releasing film. This prevents formation of voids at the interface between the mold-releasing film and the thermosetting resin and spreading of the conductive paste filled in the through-holes and enables formation of high-density via holes and manufacturing of the wiring board using the thin electrically insulating substrate with high productivity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrically insulating base material used for a high-density wiring board in which a plurality of layers of wirings are electrically connected by inner via hole connection, and a method of manufacturing a high-density wiring board using the same.

  In recent years, with the downsizing and high performance of electronic devices, multilayer wiring circuit boards capable of mounting semiconductor chips such as LSIs with high density not only for industrial use but also in the field of consumer equipment are being supplied at low cost. There has been a strong demand. In such a multilayer printed circuit board, it is important that a plurality of wiring patterns formed at a fine wiring pitch can be electrically connected with high connection reliability.

  In addition, in mobile devices represented by mobile phones, in particular, in addition to the trend of integration of functions, the trend of thinning of devices is remarkable in order to improve portability. High density and thinness is required.

  In response to such market demand, instead of the metal plated conductor on the inner wall of the through-hole, which has been the mainstream for interlayer connection of conventional multilayer wiring boards, any electrode of the multilayer printed wiring board can be placed at any wiring pattern position. There is an inner via hole connection method that can be connected, that is, an all-layer IVH structure resin multilayer substrate (see Patent Document 1). This is because it is possible to connect only necessary layers by filling the via holes of the multilayer printed wiring board and connect the necessary layers, and the inner via hole can be provided directly under the component land, so the board size is reduced. And high-density mounting can be realized. Further, since the electrical connection in the inner via hole uses a conductive paste, the stress applied to the via hole can be relieved and a stable electrical connection can be realized against a dimensional change due to a thermal shock or the like. .

  Conventionally proposed is a structure that is manufactured by the steps as shown in FIGS. 10A to 10H as the all-layer IVH structure resin multilayer substrate.

  First, the electrically insulating substrate 1 is shown in FIG. The electrically insulating substrate shown here refers to a so-called prepreg state containing an uncured component of a thermosetting resin.

  Next, as shown in FIG. 10B, release films 2 are attached to both sides of the electrically insulating substrate 1 by lamination. FIG. 8 shows this laminating method. The release film 2 is unwound from the unwinder 7 shown in FIG. 8 and passes through the laminate roll 14. The laminating roll 14 is loaded with the electrically insulating base material 1 cut into a sheet shape, and the thermosetting resin contained in the electrically insulating base material 1 is softened by heating and pressing, and is attached to the release film 2. It is attached. FIG. 8 shows an example in which the laminate rolls 14 are arranged in two stages so that the release film 2 can be attached with good productivity and no wrinkles. With such a laminating roll arrangement, even when the electrically insulating base material 1 is charged at a high speed, the electrically insulating base material is softened to some extent by the front laminating roll, and this pasting is performed by the rear laminating roll. Can be highly productive.

  Thereafter, the sheet can be cut into a sheet by a cutting machine 15, and the electrically insulating substrate 1 to which the release film 2 is attached can be formed.

  Subsequently, as shown in FIG. 10C, a through hole 3 penetrating all of the electrically insulating substrate 1 and the release film 2 is formed by a laser or the like. Next, after filling the through holes 3 with the conductive paste 4 as shown in FIG. 10 (d), the release films 2 on both sides are peeled off as shown in FIG. 10 (e). In this state, a foil-like wiring material 5 is laminated from both sides as shown in FIG. 10 (f), and the wiring material 5 is heated and pressed in the step shown in FIG. 10 (g) to adhere to the electrically insulating substrate 1. Let At this time, the conductive paste 4 is compressed in the thickness direction by the heating and pressing step. By this compression, the conductive particles in the conductive paste are brought into contact with high density, and at the same time, the electrical connection between the wiring material 5 and the conductive paste 4 is realized. Next, the double-sided substrate is completed by patterning the wiring material 5 as shown in FIG.

Moreover, the electrically insulating base material used for the above-mentioned wiring board is usually formed by the method shown in FIG. That is, the core material 6 is continuously unwound by an unwinding machine 7, immersed in an impregnation tank 9 storing a thermosetting resin varnish 8 diluted with an organic solvent, the amount of resin is adjusted by a squeeze roll 10, and a drying furnace The solvent is volatilized at 11 to obtain a semi-cured state, wound up by a winder 12, and then cut into a sheet to produce an electrically insulating substrate. As an improved method for controlling the amount of impregnated resin with high accuracy, a method for producing an electrically insulating substrate by die coating has been proposed in place of the resin amount control method using the impregnation tank 9 and the squeeze roll 10. (See Patent Document 2).
Japanese Patent Laid-Open No. 06-268345 JP 2004-188852 A

  FIGS. 9A to 9D are enlarged views of the three through-holes shown in FIGS. 10B to 10E. When the release film 2 is affixed to the electrically insulating substrate 1, as shown in FIG. 9A, the surface irregularities of the electrically insulating substrate 1, the followability of the release film 2, and the resin Due to the unevenness of impregnation, air biting at the time of lamination, etc., there are fine voids 13 between the release film 2 and the electrically insulating substrate 1.

  When the through hole 3 is processed in this state, the void 13 is exposed on the wall surface of the through hole 3 as shown in FIG. Subsequently, when the conductive paste 4 is filled into the through hole 3, the conductive paste 4 enters the void 13 as shown in FIG. 9C.

  Next, when the release film 2 is peeled off, the conductive paste 4 spreads on the surface of the electrically insulating substrate 1 as shown in FIG. The spread of the conductive paste induces deterioration of electrical insulation between the through holes or between the through holes and the wiring. In addition, since the substantial diameter of the through hole irregularly spreads in the state of interference with the void 13, the wiring formed so as to cover the through hole is designed to be sufficiently large so that the conductive paste is not exposed from the wiring. This is necessary, which hinders the miniaturization of the wiring.

  In addition, in the case of forming a thinner electrically insulating substrate by the method for manufacturing an electrically insulating substrate shown in FIG. When a thin electrically insulating base material is conveyed alone, problems such as dents and bends are likely to occur. Further, when impregnating a thin core material with a resin, there is a problem that the volume of the impregnated resin is reduced and it is difficult to control the resin content of the electrically insulating substrate with high accuracy.

  The present invention provides a higher-density wiring board by suppressing the spread of through-hole fillers such as conductive paste and miniaturizing vias / wirings, and also provides a thin electrically insulating substrate for productivity. An object of the present invention is to provide an excellent method for manufacturing a thin wiring board.

  In order to achieve the above object, the present invention has the following configuration.

  According to the first aspect of the present invention, there is provided a step of applying a thermosetting resin on one side of a release film, and at least one side of a core material, the release film is a core of the thermosetting resin. A step of laminating in a direction in contact with the material, and a step of attaching the release film to the core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate. In the impregnation step of the thermosetting resin, the uncured component of the thermosetting resin is left, and the method for producing an electrically insulating substrate is characterized in that the uncured component of the thermosetting resin remains. Therefore, it can be attached to other materials by further heating, can realize the function as an intermediate of the wiring board, and after applying the thermosetting resin on the release film in advance, the core material Release mold for pasting And voids at the interface of the thermosetting resin can be suppressed, as a result, it is possible to reduce the spread of conductive paste filled in the through-hole.

  Invention of Claim 2 of this invention is a manufacturing method of the electrically insulating base material of Claim 1 with which the heating in the impregnation process of the said thermosetting resin is performed with the temperature increase rate of 20 degree-C / min or more. By performing the thermosetting resin at a temperature rising rate of 20 ° C./min or more, the melt viscosity of the thermosetting resin can be further lowered, and the resin impregnation into the core material can be enhanced. .

  Invention of Claim 3 of this invention is a manufacturing method of the electrically insulating base material of Claim 1 in which the impregnation process of the said thermosetting resin is performed by the laminating method, Comprising: According to the laminating method, Since the core material can be impregnated with the thermosetting resin by heating to the minimum melt viscosity of the thermosetting resin in a short time, it becomes easy to leave the uncured component of the thermosetting resin.

  Invention of Claim 4 of this invention is a manufacturing method of the electrically insulating base material of Claim 1 which provides tension | tensile_strength tension to a core material in the said impregnation process of the said thermosetting resin, Comprising: By applying tensile tension to the film, it becomes possible to control the stress balance when the release film and the core material are attached, and to reduce the dimensional change when the release film is peeled off in a later step. .

  The invention according to claim 5 of the present invention is the method for manufacturing an electrically insulating substrate according to claim 1, wherein the core material is a sheet material in which fibers are intertwined with each other. Can be produced.

  Invention of Claim 6 of this invention is a manufacturing method of the electrically insulating base material of Claim 5 in which the said core material consists of a multi-layer sheet material, Comprising: A multi-layer sheet material is used as a core material. By using this, it is possible to adjust the thickness of the electrically insulating substrate by a simple method and to provide an electrically insulating substrate having different functions in the thickness direction by combining sheet materials of different materials. Is possible.

  The invention according to claim 7 of the present invention is the electrically insulating substrate according to claim 1, wherein the core material has a thickness of 40 microns or less. According to the manufacturing method of the present invention, the thickness is 40 microns. Since the following ultrathin core material is impregnated with a thermosetting resin, the thin core material is excellent in resin impregnation properties, and the generation of voids during impregnation can be reduced. Moreover, since the release film covers the surface, it is possible to increase the rigidity of the thin electrically insulating substrate and reduce problems due to handling in the manufacturing process.

  The invention according to claim 8 of the present invention is the electrically insulating substrate according to claim 1, wherein a plurality of thermosetting resins are formed on the release film, wherein a plurality of the thermosetting resins are formed on the release film. By forming the thermosetting resin of the layer, the electrically insulating substrate can be impregnated with a plurality of resins, and the function of the electrically insulating substrate can be made different in the thickness direction.

  The invention according to claim 9 of the present invention further includes a step of cutting the electrically insulating substrate into a sheet shape, and a step of applying pressure in a plane in the thickness direction of the electrically insulating substrate after cutting. It is a manufacturing method of the electrically insulating base material of Claim 1, Comprising: The curvature of the electrically insulating base material which generate | occur | produced during the manufacturing process can be corrected.

  The invention according to claim 10 of the present invention includes a step of applying a thermosetting resin on one surface of a release film, and a direction in which the release film is in contact with the core material on both surfaces of the core material. And laminating the release film on a core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate, and the electrically insulating group Forming a through hole in the material, filling the through hole with a conductive paste, peeling the release film, and laminating a wiring material on at least one side of the electrically insulating substrate; A method of manufacturing a wiring board, comprising: a step of curing the thermosetting resin by heating and pressing, and affixing the wiring material; and a step of patterning the wiring material, the method comprising: Generated at the film interface It is possible to suppress the voids can be reduced spread from the through holes of the conductive paste.

  In the invention described in claim 11 of the present invention, in the through-hole forming step, the roll-shaped electrically insulating base material is unwound to process the through-hole, and then wound into a roll shape. The method of manufacturing a wiring board according to claim 1, wherein the through-holes are formed in the roll-shaped electrically insulating base material, thereby improving the efficiency of conveyance and improving the productivity, as well as the electrically insulating substrate during through-hole processing. Variation in the dimensional change of the material due to the material holding can be suppressed.

  According to a twelfth aspect of the present invention, in the conductive paste filling step, the roll-shaped electrically insulating base material is unwound and the conductive paste is filled, and then the separator is sandwiched and wound. The method for manufacturing a wiring board according to claim 1, wherein the conductive paste is filled into a roll-shaped electrically insulating base material, so that the productivity is excellent, and the conductive paste filled by winding the separator in between The resin content inside can be discharged, and a via with excellent connectivity can be realized.

  The invention according to claim 13 of the present invention is the wiring according to claim 10, wherein in the release film peeling step, the roll-shaped electrically insulating substrate is unwound to be peeled off and cut through a drying step. It is a manufacturing method of a board | substrate, Comprising: The productivity outstanding compared with batch processing is realizable by drying in-line with respect to a roll-shaped electrically insulating base material.

  The invention according to claim 14 of the present invention is the step of applying a thermosetting resin on one side of the release film, and the direction in which the release resin is in contact with the core material on both sides of the core material. And laminating the release film on the core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate; Peeling the mold film, attaching the electrically insulating base material on the wiring substrate, forming a through hole in the electrically insulating base material, filling the through hole with a conductive paste, The step of peeling the release film on the other surface, the step of laminating the wiring material, the step of curing the thermosetting resin by heating and pressing, and the step of attaching the wiring material, and the patterning of the wiring material Wiring board with process The voids generated at the interface between the electrically insulating substrate and the release film can be suppressed, and as a result, the spread of the conductive paste from the through-holes can be reduced, and the electrically insulating group By attaching the material to the wiring board and then processing the through hole, the alignment accuracy of the through hole can be improved.

  The invention according to claim 15 of the present invention is the step of applying a thermosetting resin on one side of a release film, the step of applying a thermosetting resin on one side of a wiring material, and the thermosetting resin Laminating the release film on one surface of the core material in a direction in contact with the core material, laminating the wiring material on the other surface, and heating and pressurizing the release film and the wiring material into the core material A step of impregnating the core material with the thermosetting resin to form an electrically insulating substrate, a step of patterning the wiring material, and the wiring material exposed to the hole bottom of the electrically insulating substrate. A step of forming a through-hole, a step of filling the through-hole with a conductive paste, a step of peeling the release film, a step of laminating a plurality of the electrically insulating substrates, and heating and pressing The thermosetting resin is cured by A method of manufacturing a wiring board comprising a step of integrating an electrically insulating base material, wherein voids generated at the interface between the electrically insulating base material and the release film can be suppressed, and the conductive paste penetrates The spread from the holes can be reduced, and a multilayer wiring board can be formed at a time, thereby realizing excellent productivity.

  The invention according to claim 16 of the present invention includes the step of stacking a plurality of wiring substrates and a plurality of the electrically insulating base materials in place of the plurality of electrically insulating base materials. In this manufacturing method, a high-density wiring layer can be formed on the surface layer of the wiring board by a simple method.

  The invention according to claim 17 of the present invention includes a step of applying a thermosetting resin on one side of a release film, a step of applying a thermosetting resin on one side of a wiring material, and the thermosetting resin. Laminating the release film on one surface of the core material in a direction in contact with the core material, laminating the wiring material on the other surface, and heating and pressurizing the release film and the wiring material into the core material A step of impregnating the core material with the thermosetting resin to form an electrically insulating substrate, a step of peeling the release film, and heating and pressurizing the electrically insulating group on the wiring board. Attaching the material and curing the thermosetting resin; forming a through hole penetrating the electrically insulating substrate and the wiring material; filling the through hole with a conductor; and A process for forming a wiring pattern on the surface of a conductive substrate A method for manufacturing a wiring board, in which a thin electrically insulating base material can be laminated with good transportability, so that a thin high-density wiring layer is formed on the surface layer of the wiring board by a method with excellent productivity. Can do.

  According to the present invention, since a thermosetting resin is applied on the release film in advance and then bonded to the core material, no void is generated at the interface between the release film and the thermosetting resin, and the through hole is formed. The spread of the conductive paste to be filled can be suppressed, and as a result, a high-density wiring board can be provided.

  Further, according to the present invention, since the core material is impregnated by transfer with the thermosetting resin formed on the release film, the thin core material with low rigidity can be impregnated with the resin. Thus, it is possible to provide a method for manufacturing a thin wiring board excellent in productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 and FIG. 2 show the main manufacturing process of the electrically insulating substrate according to the present invention. As shown in FIG. 1, the release film 2 is unwound from the unwinder 7. As the release film 2, a material obtained by performing a silicone release treatment on the surface of a PET, PEN, or PPS film can be used. This release film 2 needs to withstand the heat and pressure of the subsequent laminating process, and when the laminating temperature is 150 ° C. or higher, polyimide film or fluorine resin film having excellent heat resistance can be used. Fluorine-based resin films such as Asahi Glass's Aflex (trade name), DuPont's Teflon (registered trademark), and Toray's Toyoflon (trade name) have good mold release properties, and the film surface is subjected to release treatment. There is no need to apply.

  In addition, it is sufficient for the release treatment to be able to secure the release property with the resin formed on the surface of the release film 2 regardless of silicone, and for example, an epoxy resin obtained by curing a thermosetting epoxy resin. And releasability from polyimide resin can be secured.

  Next, the resin varnish 8 is applied onto the release film 2 with a die 16. This resin varnish 8 will later constitute an electrically insulating substrate of the wiring board, and a thermosetting resin material such as an epoxy resin, a polyimide resin, a BT resin, a PPE resin, or a PPO resin can be used. Moreover, you may add inorganic fillers, such as an alumina, a silica, and aluminum hydroxide, from the point of a thermal expansion coefficient, hardness, thermal conductivity, and a flame retardance.

  Moreover, this resin varnish 8 is diluted with a solvent, and the viscosity is adjusted. As a diluting solvent, it is common to use THF (Tetrahydrofuran), DMF (N, N dimethylformamide) and a mixed solvent thereof.

  The resin varnish 8 is supplied to the die 16 using a pump, and can be applied to the resin varnish 8 with a uniform thickness by controlling the distance between the die 16 and the release film 2. The coating thickness here is set in consideration of the amount that the solvent for dilution dries in the subsequent drying step and the thickness decreases, and the adjustment of the conditions is performed while measuring the resin thickness after drying. It is to include.

  Further, in the figure, the example of the die coater using the die 16 is described, but the coating method is not limited to this, and is generally used for reverse coater, comma coater, gravure printing and the like. Can be selected according to the viscosity of the resin material and the coating thickness.

  Next, the resin varnish 8 is dried in the drying furnace 11. In this drying step, the diluted solvent contained in the resin varnish is removed and the cured state of the resin is controlled. As parameters at this time, temperature, air volume, and feed speed are adjusted. The cured state of the resin is adjusted to such an extent that the resin flows in the subsequent laminating process. If the resin is a thermosetting resin, a sufficiently uncured component remains.

  Subsequently, the release film 2 on which the resin has been applied is wound up by the winder 12. Here, the figure shows an example in which the resin does not have tackiness and can be wound as it is. However, if the resin has tackiness, it may of course be wound with a separator interposed therebetween.

  Next, FIG. 2 shows a process of impregnating the core material 6 with resin. The release film 2 formed in the step of FIG. 1 is unwound by the unwinding machine 17, and the core material 6 is unwound by the unwinding machine 7.

  Here, as a material of the core material 6, rigidity is imparted to the insulating base material of the wiring board, and a sheet material in which fibers are intertwined is preferable. As the core material 6, a woven fabric or nonwoven fabric formed from glass fibers, a woven fabric or nonwoven fabric of organic fibers, or a porous sheet of organic material can be used. Examples of organic fiber core materials include aramid nonwoven fabrics, LCP nonwoven fabrics, and organic material porous sheets include aramid and polyimide porous sheets.

  Further, the sheet thickness is more preferably 40 microns or less, and since the thickness is thin, it is easy to impregnate the resin in a later step, and generation of voids mixed in the electrically insulating substrate can be suppressed. In addition, in order to improve the impregnation property of the thermosetting resin to the core material 6, the core material 6 may be subjected to plasma treatment or the like in advance, or a silane coupling agent or the like is performed to improve the wettability with the resin. It is more preferable to keep it.

  Here, although FIG. 2 shows an example in which one type is used as the core material 6, a plurality of rolls of the core material 6 may be laminated. As an example, in order to increase the rigidity of the electrically insulating substrate, two aramid nonwoven fabrics having a thickness of 40 microns can be stacked and used as a core material.

  Moreover, the function of an electrically insulating base material can be improved by laminating | stacking several types of materials as the core material 6. FIG. As an example, LCP nonwoven fabric is a material with low epsilon, low Tanδ and excellent high-frequency characteristics, but has a low elastic modulus and low rigidity. Therefore, an electrically insulating base material having a balance between rigidity and electrical characteristics can be formed by overlapping with an aramid nonwoven fabric.

  Next, the release film 2 is affixed to the core material 6 with the laminate roll 14, and at the same time, the thermosetting resin formed on the release film 2 is impregnated into the core material 6. Here, like the conventional example, an example is shown in which the laminate rolls 14 are arranged in two stages so that the release film 2 can be attached without wrinkling. With such a laminating roll arrangement, even when the core material 6 is introduced at a high speed, the thermosetting resin on the release film is softened to some extent by the front laminating roll, and this pasting is performed by the rear laminating roll. It can be performed and has excellent productivity.

  As the lamination conditions, the temperature, pressure, and speed are controlled so that the thermosetting resin formed on the release film 2 can be softened and liquefied so that the core material can be impregnated.

  Generally, when the temperature is increased with respect to an uncured thermosetting resin, the resin begins to soften first. Thereafter, as the temperature rise continues, it becomes softer and in some cases becomes liquid. When the temperature reaches the curing temperature, curing of the resin starts and the resin changes hard. As described above, the viscosity of the resin depends on the temperature, and there exists a temperature at which the viscosity is minimum, and the viscosity at that time is defined as the minimum melt viscosity. Further, this minimum melt viscosity shows a lower value because the heat energy given to the view-curing resin decreases as the heating rate increases.

  Based on the properties of such a thermosetting resin, by setting the rate of temperature increase applied to the thermosetting resin at the time of lamination as 20 ° C./min or more, the melt viscosity can be suppressed to 1000 Pa · s or less, Good impregnation properties could be secured.

  Here, it is important to leave the uncured component of the thermosetting resin during the laminating process when the electrically insulating base material of the present invention is used as an intermediate material (so-called prepreg) of the wiring board. That is, it is necessary to exhibit adhesiveness with other materials in the subsequent manufacturing process of the wiring board, and the uncured component remains in the present laminating process. Therefore, it is necessary to control the time above the curing temperature of the resin as much as possible, and it is more preferable to provide a cooling laminate roll behind the laminating roll.

  In addition, pressure is applied in order to improve the impregnation property during lamination. As an example, by laminating a thermosetting epoxy resin at a laminating temperature of 150 ° C., a laminating pressure of 4 kgf, and a laminating speed of 1 m / min, a 30-micron thick aramid nonwoven fabric core material could be impregnated with the epoxy resin.

  In addition, the release film 2 sent to the laminate roll 14 is tensioned in the pulling direction so as to be stuck without wrinkles. That is, the release film 2 is stuck to the core material 6 in a state where it is stretched by the tensile stress.

  According to the above-described conventional manufacturing method, since the cut sheet-shaped electrically insulating base material is laminated, stress is generated in the direction in which the stretched release film contracts after lamination. The material was changing in the direction of large shrinkage. On the other hand, when the release film 2 was peeled off in a later step, the shrinkage stress was released, so that the electrical insulating base material 1 was changed in the extending direction.

  Therefore, the core material 6 is handled in the form of a roll and is continuously supplied to the laminate roll 14, and tension is also applied to the core material 6 in the tension direction. This tension can alleviate the stress difference caused by tension with the release film, and can reduce the above-mentioned dimensional change. The tension is preferably adjusted so as to be substantially the same as the tension applied to the release film 2.

  Furthermore, as shown in the prior art, when laminating a cut sheet-like electrically insulating substrate, the strain applied to the sheet during lamination is affected by the edges of the four sides, and the sheet is complicatedly distorted. This is a factor that complicates dimensional changes due to stress release when the release film is peeled off. However, by supplying the core material 6 in a roll shape, the end sides become two places, the strained state is made uniform, and variation in dimensional change due to peeling of the release film can be reduced.

  Thereafter, the sheet can be cut into a sheet by a cutting machine 15, and the electrically insulating substrate 1 to which the release film 2 is attached can be formed. Here, when the release film 2 to which the thermosetting resin is applied is laminated with the same material structure from both sides of the core material 6, the material structure is symmetric in the thickness direction, and the occurrence of warpage is suppressed. be able to.

On the other hand, those having different release film thicknesses and those having different thicknesses, materials and the like of the applied thermosetting resin can be laminated. In the case of such an asymmetric configuration in the thickness direction, warpage occurs in the electrically insulating substrate after cutting. Therefore, the warp can be corrected by pressing the electrically insulating substrate after cutting with a flat surface using a flat plate such as a metal plate in the thickness direction. Further, the warp can be corrected more effectively by applying more temperature. About this temperature, a temperature sufficiently lower than the curing temperature of the electrically insulating substrate is necessary, and as an example, warp correction was performed at 60 ° C. and 0.5 kg / cm ² . Of course, this condition can be adjusted according to the state of warpage. Here, an example of warping due to the material configuration is shown, but warping occurs due to mechanical stress due to winding, for example, when winding after winding and then cutting. According to the present invention, it is possible to reduce warpage due to such mechanical stress.

  In addition, in the above-mentioned example, although demonstrated using the structure which forms a single layer of thermosetting resin in the release film 2, you may form several layers on a release film as a thermosetting resin. . As a result, the electrically insulating base material can be impregnated with a plurality of resins, and the functions can be made different in the thickness direction. As an example, when imparting electrical characteristics and adhesion to an electrically insulating substrate, an epoxy resin layer and a PPO resin layer may be laminated as the resin layer. That is, the electrically insulating base material has a configuration in which the central portion of the core material 6 is impregnated with PPO resin and the surface portion has epoxy resin. As a result, it is possible to reduce the dielectric constant with the PPO resin in the central portion while securing the adhesion to the wiring material such as copper foil with the epoxy resin.

  Further, two epoxy resin layers may be formed on the release film 2. When the first epoxy layer to be formed on the release film 2 is cured by drying and an uncured epoxy resin layer is formed thereon, the peelability between the first and second layers is improved. It can be secured. That is, an epoxy resin can be used as a mold release process. That is, it is possible to suppress a slight transfer of the silicone treatment to the resin side that occurs when the release treatment is imparted by the silicone treatment on the release film 2, and the adhesion and insulation characteristics of the electrically insulating substrate 1. Can be reduced.

  The release film 2 to be attached to the core material 6 is not limited to the above example, and the thickness and material of the thermosetting resin can be set separately on the front and back surfaces according to the desired function. Not too long. According to the present invention, different thermosetting resins can be impregnated from the front and back surfaces of the core material 6 by a simple method with good controllability.

  In addition, although demonstrated using the example which laminates the roll-shaped core material 6 in FIG. 2, of course, you may laminate the core material of a cut sheet.

(Embodiment 2)
Next, the manufacturing method of the wiring board concerning Embodiment 2 of this invention is demonstrated using figures. FIG. 3 shows a cross-sectional view of main steps of the method for manufacturing a wiring board according to the present invention. In FIG. 3, a wiring board is formed using the electrically insulating base material already described in the first embodiment, and portions overlapping with the above example will be described in a simplified manner.

  First, FIG. 3A shows a state in which an uncured thermosetting resin 18 is formed on the release film 2. For the thermosetting resin 18, the material such as the epoxy resin already described in the first embodiment is used, and the coating process can be performed using a die coater or the like.

  Next, as shown in FIG. 3B, the release film 2 on which the thermosetting resin 18 is formed is laminated on both sides of the core material 6, and the core material 6 is impregnated with the thermosetting resin 18 by lamination or the like. If it does, it will be in the state of the electrically insulating base material 1 shown in FIG.3 (c). This is the same as that already described in the first embodiment, and since the uncured component of the thermosetting resin remains, it can be attached to another material by further heating. In addition to being able to realize the function as an intermediate of the product, since a thermosetting resin is applied on the release film in advance and then bonded to the core material, voids may occur at the interface between the release film and the thermosetting resin. In addition, it is possible to suppress the spread of the conductive paste filled in the through-holes described later.

  Next, the through hole 3 is formed as shown in FIG. For the processing of the through-hole 3, punching, laser processing, or the like can be used, but it is more preferable to use laser processing because it is excellent in productivity. As the laser, a carbon dioxide gas laser or a YAG laser can be used, and a through hole having a diameter of 100 to 50 microns can be formed. In this through-hole forming step, through-holes are formed at coordinates corrected for dimensional changes when the subsequent release film 2 is peeled off. That is, the processing coordinates of the through hole are set in anticipation of the amount by which the dimension of the electrically insulating substrate 1 changes when the release film 2 is peeled off.

  In addition, securing the flatness of the electrically insulating substrate 1 in the through hole forming step is important for processing the through holes with high positional accuracy and stabilizing the processed shape. The through-hole is processed in a state where is pulled in the plane direction.

  Here, it is more preferable that the electrically insulating substrate 1 is formed in a roll shape and the through hole is formed in that state. That is, the electrically insulating substrate is unwound in the form of a roll, and after the through hole is processed, it is wound up. When the through-hole is processed while holding the electrically insulating base material 1 in a roll shape, it becomes easy to apply a tensile tension for ensuring the flatness of the electrically insulating base material 1 over the entire side. It is possible to make the strain state of the insulating base material uniform. Thereby, the positional variation of the through holes can be reduced.

  Moreover, when the electrically insulating base material 1 becomes thin, it becomes easy to generate | occur | produce bending and a wrinkle in conveyance and handling, and it becomes difficult to process an electrically insulating base material with a sufficient yield. Therefore, by handling the electrically insulating substrate 1 in a roll shape, this problem can be solved and productivity can be improved.

  Subsequently, as shown in FIG. 3 (e), the conductive paste 4 is filled in the through holes 3. As the conductive paste, a composite material of metal particles such as copper, silver, gold, platinum, and solder and a resin can be used. At this time, the release film 2 plays the role of protecting the conductive paste 4 from adhering to the surface of the electrically insulating substrate and the role of securing the filling amount of the conductive paste. Since the conductive paste can be filled by printing, it has an advantage of excellent productivity. In this conductive paste filling step, as shown in the conventional example, when a void exists between the release film 2 and the electrically insulating substrate 1, the conductive paste 4 also flows out along the void. However, in the present invention, since voids at the interface are suppressed, the flow of the conductive paste 4 can be reduced.

  Also in this conductive paste filling step, it is more preferable to handle the electrically insulating substrate 1 in a roll shape, as in the through hole forming step. By handling in the form of a roll, not only the transport and handling properties of the thin electrically insulating substrate 1 are improved, but also the resin component can be sucked in by a capillary phenomenon such as thin paper when wound into a roll. A porous material can be sandwiched as a separator. Since the electrically insulating base material 1 is wound through the separator, the separator and the electrically insulating base material 1 are in close contact with each other without any gaps, thereby effectively discharging the resin component in the conductive paste. Can do. That is, it is possible to increase the conductive particle density of the conductive paste and improve the contact property between the conductive particles in the subsequent pressing step.

  Next, as shown in FIG.3 (f), the release film 2 is peeled. Here, as shown in the figure, the conductive paste 4 has a shape protruding from the surface of the electrically insulating substrate 1 by the thickness of the release film 2. A large amount of the conductive paste can be secured by this protrusion. Setting the thickness of the release film 2 to about 5 to 25% of the via diameter is more preferable because the amount of the conductive paste taken to the release film side when the release film 2 is peeled can be suppressed. As in the conventional example, the conductive paste spread between the release film 2 and the electrically insulating base material 1 is likely to scatter when the release film 2 is peeled off, and is reattached to the electrically insulating base material for insulation. It causes a defect. According to the present invention, such scattering of the conductive paste can be suppressed and insulation failure can be reduced.

  Next, as shown in FIG. 3G, the wiring material 5 such as copper foil is laminated from both sides, and the electrically insulating base material is cured and bonded to the wiring material 5 by heat and pressure such as hot press. And the state shown in FIG.

  In addition, it is more preferable to dry the electrically insulating base material 1 on the conditions which the thermosetting resin contained in the electrically insulating base material 1 does not harden | cure before this lamination process. When the electrical insulating substrate 1 absorbs moisture, if the moisture absorption amount is large, moisture may not be sufficiently removed in the hot pressing step, and delamination after the hot pressing is induced. Therefore, in the release film peeling step, the roll-shaped electrically insulating base material is unwound and peeled off, a roll-like drying step is performed, and then the electrically insulating base material is cut. Thus, by releasing the release film in a roll shape, it is not necessary to perform chucking for releasing the release film for each cut sheet, and the productivity is excellent. Moreover, by drying in roll form, an in-line drying furnace can be used and it is excellent in productivity.

  Further, in the step shown in FIG. 3 (h), the conductive paste protruding from the above-described electrically insulating base material is compressed in the thickness direction, and as a result, the conductive particles in the conductive paste are high. By contacting the density, electrical connection between the conductive paste and the wiring material can be ensured in the conductive paste. This high-density contact of the conductive particles is realized by discharging the resin component in the conductive paste to the outside of the through-hole by compression. This was done actively before the wiring material was laminated. In addition, the electrically insulating substrate of the present invention does not hinder the adhesion to the wiring material because the uncured component remains when the core material of the thermosetting resin is impregnated.

  Subsequently, when the wiring material 5 is patterned by etching, the state shown in FIG. 3I is obtained, and a double-sided substrate can be formed.

  In addition, on both sides of the double-sided substrate, an electrically insulating base material having a through-hole having the same configuration as in FIG. 3F and a wiring material are laminated and bonded by hot pressing, and the outer wiring material is patterned by etching. Thus, a multilayer substrate can be manufactured by a simple method.

(Embodiment 3)
The wiring board according to the present embodiment can also be formed by the manufacturing method shown in FIGS. Here, the description overlapping with the example described above will be described in a simplified manner.

  As shown in FIG. 4A, a thermosetting resin 18 is formed on the release film 2. This thermosetting resin is in a state where uncured components remain, as in the example shown in the second embodiment. Next, as shown in FIG. 4 (b), the release film 2 to which the thermosetting resin 18 is applied is laminated from both sides of the core material 6 and attached by lamination or the like, and the thermosetting resin 18 is attached to the core material. 6 is impregnated, an electrically insulating substrate 1 having a release film 2 shown in FIG.

  Next, as shown in FIG. 4D, when the release film 2 on one side of the electrically insulating base material 1 is peeled off and laminated with the double-sided substrate 19, the state shown in FIG. Become. This affixing process needs to be performed under conditions where the thermosetting resin 18 is not cured, and is preferably affixed in a short time by lamination or the like. Alternatively, the release film 2 on which the double-sided substrate 1, the core material 6, and the thermosetting resin 18 are directly formed may be attached by lamination.

  In the figure, a substrate having an IVH structure is shown as a double-sided substrate. However, the same effect can be obtained with another structure substrate such as a through-hole substrate, and the number of layers and the structure are not limited thereto.

  Next, as shown in FIG.4 (f), the through-hole 3 is formed by the laser processing from the mold release film 2 side. In this laser processing, the wiring pattern is exposed at the bottom of the through hole.

  Next, when the through-hole 3 is filled with the conductive paste 4, the state shown in FIG. 4G is obtained. In this filling process, in order to fill the through-hole with the hole bottom blocked with the conductive paste, printing in vacuum, vacuum defoaming or centrifugal filling is performed, and repeated printing and filling reduces the filling amount of the conductive paste. It is preferable in terms of ensuring stability. For through holes with a high aspect ratio, it is desirable to incline the wall surface of the through holes from the viewpoint of filling with conductive paste.

  Next, when the release film 2 is peeled and a copper foil is laminated as the wiring material 5, the state shown in FIG. 4 (h) is obtained. Next, as shown in FIG. 4 (i), the wiring material 5 is bonded to the electrically insulating substrate 1 in the heating and pressing step. At this time, compression is applied to the conductive paste 4 inside the through-hole 3, and the wiring material 5 and the conductive paste come into contact with each other at a high density.

  Next, when the wiring material 5 is patterned by etching, a wiring substrate shown in FIG. 4J is formed.

  According to the above-described method for manufacturing a wiring board, voids generated at the interface between the electrically insulating base and the release film can be suppressed, and the conductive paste can be prevented from spreading from the through hole. Moreover, after attaching an electrically insulating base material to a wiring board, a through-hole can be processed according to the position of wiring by processing a through-hole, As a result, alignment accuracy can be improved.

  Moreover, since a thin material of 40 microns or less can be formed as the electrically insulating base material 1, a thin multilayer wiring board can be formed.

(Embodiment 4)
Next, another embodiment of the method for manufacturing a wiring board according to the present invention will be described in detail with reference to FIGS. Note that portions that overlap with the above-described embodiment are simplified.

  As shown in FIG. 5A, the thermosetting resin 18 is formed on the release film 2. The formation of the thermosetting resin is the same as the example already described. Further, a thermosetting resin 18 is formed on the wiring material 5 as shown in FIG. This is obtained by replacing the release film of the example described in FIG. 5A with a wiring material, and the other parts are the same.

  Next, the release film 2 on which the thermosetting resin 18 shown in FIGS. 5A and 5B is formed on both sides of the core material 6 and the wiring material 5 on which the thermosetting resin 18 is formed are heated. When the curable resin 18 is laminated in a direction in contact with the core material 6, the state shown in FIG.

  Subsequently, as shown in FIG. 5D, the core material 6 is impregnated with the thermosetting resin 18 by lamination or the like. Here, the electrically insulating substrate 1 in which the wiring material 5 and the release film 2 are bonded is obtained. Here, in the thermosetting resin 18, the uncured component remains as in the above-described embodiment.

  Next, when the wiring material 5 is etched to form a desired wiring pattern, the state shown in FIG. 5E is obtained.

  Thereafter, as shown in FIG. 5 (f), the through hole 3 is formed in the electrically insulating substrate 1 so that the wiring pattern is exposed at the bottom of the hole. This through-hole formation is generally performed by laser processing. Depending on the state of laser processing, the resin of the electrically insulating substrate may remain at the bottom of the through hole, and it is more preferable to carry out desmearing with plasma or a chemical solution after laser processing. For this laser processing, since the wiring pattern has already been formed, the position of this wiring pattern is recognized, the deviation from the design dimension of the wiring pattern is measured in advance, and the via processing data is corrected, so that the through-hole is corrected. The through hole can be formed with high accuracy on the land to be disposed.

  Next, when the conductive paste 4 is filled in the through hole 3, the state shown in FIG. Further, an organic solvent may be added as a binder of the conductive paste, whereby the viscosity of the conductive paste is lowered and the filling property to the through holes can be improved. In particular, as in the example shown in FIG. 5, it is difficult to fill the bottomed through-hole with the conductive paste to the bottom of the hole with high density, and it is difficult to defoam in vacuum or print in vacuum. By introducing such a printing method, more stable conductive paste filling can be realized.

  Next, when an organic solvent is added to the conductive paste, drying is preferably performed. This drying step may be performed near the boiling point of the organic solvent in terms of shortening the drying time.

  Next, when the release film 2 is peeled from the state shown in FIG. 5G and positioned and laminated on both sides of the double-sided substrate 19, the state shown in FIG. 5H is obtained. When the electrically insulating base material 1 is subsequently adhered to the double-sided substrate 19 by heating and pressing, electrical connection can be ensured between the conductive paste 4 and the wiring pattern on the double-sided substrate, and FIG. The multilayer wiring board shown in FIG. Here, the double-sided substrate 19 is not limited to the illustrated structure, as in the example described in the third embodiment.

  Further, the positioning lamination shown in FIG. 5H is not limited to the illustrated example, and only a plurality of structures obtained by peeling the release film from the electrically insulating substrate shown in FIG. Layers may be laminated to form a multilayer wiring board.

  According to the present invention, voids generated at the interface between the electrically insulating base material and the release film can be suppressed, the conductive paste can be prevented from spreading from the through holes, and a multilayer wiring board can be formed at once. And can achieve excellent productivity.

(Embodiment 5)
Next, another embodiment of the method for manufacturing a wiring board according to the present invention will be described in detail with reference to FIGS. Note that portions that overlap with the above-described embodiment are simplified.

  The state shown in FIGS. 6A and 6B is the same as the state shown in FIGS. 5A and 5B, and in FIG. 6A, the thermosetting resin 18 is formed on the release film 2. Is formed. Further, a thermosetting resin 18 is formed on the wiring material 5 as shown in FIG.

  Next, the release film 2 in which the thermosetting resin 18 shown in FIGS. 6A and 6B is formed on both sides of the core material 6 and the wiring material 5 in which the thermosetting resin 18 is formed are heated. When the curable resin 18 is laminated in a direction in contact with the core material 6, the state shown in FIG. Subsequently, as shown in FIG. 6D, the core material 6 is impregnated with the thermosetting resin 18 by lamination or the like, and the electrically insulating base material 1 in which the wiring material and the release film 2 are bonded is obtained. Here, in the thermosetting resin 18, the uncured component remains as in the above-described embodiment. This electrically insulating substrate is in the same state as shown in FIG.

  Next, as shown in FIG. 6 (e), the release film 2 on the surface is peeled and laminated on both sides of the wiring board 20. Here, although shown as an example of a four-layer board provided with through-holes as the wiring board 20, the structure of the wiring board is not limited to this, and the number of layers of the board such as an IVH structure board, a double-sided board, etc. Can be replaced regardless of structure.

  Next, as shown in FIG. 6 (f), the thermosetting resin 18 is cured by heating and pressing with a hot press, and the electrically insulating base material 1 is bonded to the wiring board 20.

  Next, as shown in FIG. 6G, a through hole 3 is formed that penetrates the wiring material 5 on the surface and the electrically insulating base material 1 and exposes the wiring pattern of the wiring board 20 at the bottom of the hole. The formation of the through hole 3 is preferably performed by laser processing as in the fourth embodiment. Here, since the wiring material 5 and the electrically insulating substrate 1 are simultaneously processed by laser processing, the wiring material 5 is preferably thin, or a thin wiring material having a thickness of 5 microns is used or the wiring material is uniformly etched. The thickness is about 5 microns.

  Next, as shown in FIG. 6H, a plating conductor is formed as a conductor that electrically connects the wiring material 5 and the wiring pattern of the wiring board 20. About plating, it carried out combining electroless copper plating and electrolytic copper plating. Although the figure shows an example in which plating is formed on the wall surface of the through hole, plating may be performed so as to close the through hole 3. Subsequently, when the surface wiring material 5 is patterned by etching, the wiring substrate shown in FIG. 6I can be formed. Although an example in which plating is performed as the conductor is shown here, a conductive paste may be printed as the conductor, or a thin film may be formed by vapor deposition or sputtering.

  In the above example, laser processing is performed in which the wiring material 5 and the electrically insulating substrate 1 are simultaneously penetrated. However, as a method of forming the through hole 3, the position of the through hole of the wiring material 5 is previously etched. Alternatively, the through hole may be formed using the wiring material as a mask for laser processing, or the laser processing may be performed after the neighboring region including the through hole position or the entire surface of the wiring material is removed by etching.

  According to the present invention, since a thin electrically insulating substrate can be laminated with excellent handling properties, it is easy to form fine through holes, and a small diameter of 50 microns or less can be realized as the through holes. As a result, a thin high-density wiring layer can be formed on the surface layer of the wiring board by a method with excellent productivity.

  According to the method for manufacturing an electrically insulating substrate and a wiring board according to the present invention, a thermosetting resin is applied on a release film in advance, and then bonded to a core material. No void is generated at the interface, and the spread of the conductive paste filled in the through hole can be suppressed. As a result, a high-density wiring board can be provided. Moreover, since the core material is impregnated into the core material by transfer with the thermosetting resin formed on the release film, the thin core material with low rigidity can be impregnated with the resin. As a result, the thin electrically insulating substrate Can provide. That is, the present invention is useful for high-density and thin wiring boards.

Main manufacturing process diagram of electrically insulating base material in Embodiment 1 of the present invention Main manufacturing process diagram of electrically insulating base material in Embodiment 1 of the present invention (A)-(i) Process sectional drawing which showed the manufacturing method of the wiring board in Embodiment 2 of this invention for every main process (A)-(j) Process sectional drawing which showed the manufacturing method of the wiring board in Embodiment 3 of this invention for every main process. (A)-(i) Process sectional drawing which showed the manufacturing method of the wiring board in Embodiment 4 of this invention for every main process. (A)-(i) Process sectional drawing which showed the manufacturing method of the wiring board in Embodiment 5 of this invention for every main process Main manufacturing process diagram of conventional electrically insulating substrate Main manufacturing process diagram of conventional electrically insulating substrate Process cross-sectional view showing the enlarged main manufacturing process of a conventional wiring board Process cross-sectional view showing a conventional wiring board manufacturing method for each main process

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrical insulating base material 2 Release film 3 Through-hole 4 Conductive paste 5 Wiring material 6 Core material 7 Unwinding machine 8 Resin varnish 9 Impregnation tank 10 Squeeze roll 11 Drying furnace 12 Winding machine 13 Void 14 Laminating roll 15 Cutting Machine 16 Die 17 Unwinding machine 18 Thermosetting resin 19 Double-sided board 20 Wiring board

Claims (17)

Applying a thermosetting resin on one side of the release film;
Laminating the release film on at least one surface of the core material in a direction in which the thermosetting resin is in contact with the core material;
A step of attaching the release film to the core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate;
In the impregnation step of the thermosetting resin, an uncured component of the thermosetting resin is left. The manufacturing method of the electrically insulating base material of Claim 1 with which the heating in the impregnation process of the said thermosetting resin is performed with the temperature increase rate of 20 degree-C / min or more. The method for manufacturing an electrically insulating substrate according to claim 1, wherein the impregnation step of the thermosetting resin is performed by a laminating method. The method for producing an electrically insulating base material according to claim 1, wherein a tensile tension is applied to the core material in the impregnation step of the thermosetting resin. The method for producing an electrically insulating substrate according to claim 1, wherein the core material is a sheet material in which fibers are intertwined. The method for manufacturing an electrically insulating substrate according to claim 5, wherein the core material is made of a plurality of layers of sheet material. The electrically insulating substrate according to claim 1, wherein the core material has a thickness of 40 microns or less. The electrically insulating substrate according to claim 1, wherein a plurality of thermosetting resins are formed on the release film. The electrical insulating base material according to claim 1, further comprising a step of cutting the electrical insulating base material into a sheet shape and a step of applying pressure in a plane in the thickness direction of the electrical insulating base material after cutting. Production method. Applying a thermosetting resin on one side of the release film;
Laminating the release film on both sides of the core material in a direction in which the thermosetting resin is in contact with the core material;
Attaching the release film to a core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate;
Forming a through hole in the electrically insulating substrate;
Filling the through hole with a conductive paste;
Peeling the release film;
Laminating a wiring material on at least one side of the electrically insulating substrate;
Curing the thermosetting resin by heating and pressing, and affixing the wiring material;
A method of manufacturing a wiring board, comprising a step of patterning the wiring material. The said through-hole formation process is a manufacturing method of the wiring board of Claim 10 which winds up in roll shape, after unwinding a roll-shaped electrically insulating base material and processing the said through-hole. The method of manufacturing a wiring board according to claim 10, wherein the conductive paste filling step unwinds and winds a separator after unwinding a roll-shaped electrically insulating base material and filling the conductive paste. The method for manufacturing a wiring board according to claim 10, wherein in the release film peeling step, the roll-shaped electrically insulating base material is unwound and peeled off, and cut through a drying step. Applying a thermosetting resin on one side of the release film;
Laminating the release film on both sides of the core material in a direction in which the thermosetting resin is in contact with the core material;
Attaching the release film to a core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate;
A step of peeling the release film on one side and affixing the electrically insulating substrate on a wiring board;
Forming a through hole in the electrically insulating substrate;
Filling the through hole with a conductive paste;
Peeling the release film on the other side;
A step of laminating wiring materials;
Curing the thermosetting resin by heating and pressing, and affixing the wiring material;
A method of manufacturing a wiring board, comprising a step of patterning the wiring material. Applying a thermosetting resin on one side of the release film;
Applying a thermosetting resin to one side of the wiring material;
In the direction where the thermosetting resin is in contact with the core material, the release film is laminated on one surface of the core material,
Laminating a wiring material on the other surface;
Attaching the release film and the wiring material to a core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate;
Patterning the wiring material;
Forming a through hole so that the wiring material is exposed at the bottom of the hole in the electrically insulating substrate;
Filling the through hole with a conductive paste;
Peeling the release film;
A step of laminating a plurality of the electrically insulating substrates;
A method for manufacturing a wiring board, comprising: a step of curing the thermosetting resin by heating and pressing to integrate the plurality of electrically insulating substrates. The method for manufacturing a wiring board according to claim 15, further comprising a step of stacking a plurality of wiring boards and the plurality of electrically insulating base materials in place of the plurality of electrically insulating base materials. Applying a thermosetting resin on one side of the release film;
Applying a thermosetting resin to one side of the wiring material;
In the direction where the thermosetting resin is in contact with the core material, the release film is laminated on one surface of the core material,
Laminating a wiring material on the other surface;
Attaching the release film and the wiring material to a core material by heating and pressing, and impregnating the core material with the thermosetting resin to form an electrically insulating substrate;
Peeling the release film;
Pasting the electrical insulating base material on the wiring substrate by heating and pressing, and curing the thermosetting resin;
Forming a through hole penetrating the electrically insulating substrate and the wiring material;
Filling the through hole with a conductor;
A method for manufacturing a wiring board, comprising a step of forming a wiring pattern on a surface of the electrically insulating substrate.

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