JP2006176677A - Composite, prepreg using the same, metallic foil lined laminate, printed wiring substrate and method for manufacturing printed wiring substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite which sufficiently excels in adhesion reliability and sufficiently inhibits formation of a resin powder or fibers having a fear of falling off. <P>SOLUTION: The composite is obtained by impregnating a fibrous sheet with a curable resin composition and has a storage modulus at 25°C of a cured product of the curable resin composition of 100-2,000 MPa. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite, a prepreg using the composite, a metal foil-clad laminate, a printed wiring board, and a method for manufacturing the printed wiring board.

  In recent years, there has been a demand for further reduction in size and weight of electronic devices and digitization and speeding up of electronic circuits. Further, a printed wiring board to be mounted on them is required to have a higher density, and the development of these printed wiring boards themselves is an important factor in the development of new electronic devices.

  A glass epoxy substrate is known as a general high-density mounting substrate. This is a glass woven fabric impregnated with a heat-resistant epoxy resin as an insulating substrate material. The glass epoxy multilayer substrate is basically formed by, for example, bonding a copper foil to a glass woven fabric impregnated with an epoxy resin (hereinafter referred to as “prepreg”) by hot pressing, and patterning by photolithography technology. It is formed by further hot pressing with another prepreg and copper foil. Through holes are formed in the laminate using a drill, and a copper electrode is formed on the inner wall by a plating method to make electrical connection between the respective layers. In general, a copper pattern on the surface is formed by an etching method.

  However, it cannot be said that the glass epoxy multilayer substrate formed in this way is sufficient for the demand for higher density. Since a normal glass epoxy multilayer substrate has through-holes, when performing high-density wiring, the through-holes narrow the wiring space, and it is necessary to form a wiring pattern around the through-holes. Arise. As a result, the wiring length is increased. In addition, since wiring space is small, automatic wiring by CAD becomes difficult. Furthermore, drilling is difficult when forming a small-diameter through hole, and the cost ratio required for drilling is high. Moreover, the copper plating process required for the through hole is a problem from the viewpoint of the global environment. Further, the double-sided board has the same problem. Particularly, when a through-hole part is present in component mounting, a high-density board cannot be obtained because the part cannot be mounted on that part.

  For such a problem, a printed wiring board having a complete inner via hole (IVH) configuration has been proposed. In the IVH structure, it is possible to connect only necessary layers, and there is no through hole in the uppermost layer of the substrate, and the mountability is excellent.

  As a circuit board having this IVH structure, for example, a through hole is formed by laser processing on a sheet substrate material obtained by impregnating a sheet-like organic nonwoven fabric with a thermosetting resin, and this through hole is filled with a conductive paste. And the circuit board which formed the IVH structure by heating-pressing a sheet | seat board | substrate material is proposed (for example, refer patent document 1).

  An example of the multilayer substrate having an IVH structure is an SLC substrate (registered trademark). The SLC substrate (registered trademark) is formed by coating a resin as an insulating material on a double-sided substrate having a normal copper pattern layer, forming a via hole by a photolithographic method, and then adding copper plating to the entire surface to form a lower conductor. And via hole and surface layer. Similarly, a pattern is formed by the photolithography method, and this process is repeated to form a multilayer. This method is attracting attention because it is very inexpensive and can form highly accurate wiring.

Furthermore, the multilayer board | substrate using a thermoplastic resin is mentioned as a multilayer board | substrate which has IVH structure. For multilayer substrates using thermoplastic resin, via holes are formed in a thermoplastic sheet-like base material, pattern printing is performed on the sheet surface with an Ag-based resin conductive paste, and separately manufactured sheets are stacked and hot pressed. This is a multi-layered substrate.
JP-A-6-268345

  However, the printed wiring board having the IVH structure as described above has a sufficient reliability because a dent may be generated on the board during the manufacture or the wiring may be disconnected. There was no one. In particular, when the thickness of each layer is reduced in order to increase the density, the above-described defects tend to occur frequently.

  Therefore, as a result of examining the cause of the defect in detail, the present inventors, as described above, when the sheet substrate material in which the fiber sheet is impregnated with the resin is used as the insulating substrate, the resin powder or fibers that fall off from the insulating substrate Has been found to be a major cause of the above defects. Further, it has been found that a large amount of resin powder or fiber that falls off is generated particularly when an insulating substrate having a via hole is formed.

  Here, even if the material for the insulating substrate is selected only considering the suppression of the dropping of resin powder or fiber, if the insulating substrate used for the printed circuit board does not have sufficient adhesive reliability, As a result, a printed wiring board having sufficient reliability cannot be obtained.

  An object of the present invention is to solve the above-mentioned problems, and to provide a composite that is sufficiently excellent in adhesion reliability and sufficiently suppressed from generating resin powder or fibers that may drop off. . Another object of the present invention is to provide a prepreg, a metal foil-clad laminate, a printed wiring board, and a manufacturing method thereof using such a composite.

  In order to achieve the above object, the composite of the present invention is a composite comprising a fiber sheet impregnated with a curable resin composition, and the cured product of the curable resin composition has a storage elastic modulus at 25 ° C. 100 to 2000 MPa.

  In the composite of the present invention, the fiber sheet is impregnated with a curable resin composition in which the storage modulus of the cured product falls within the above range, thereby sufficiently suppressing the occurrence of resin powder or fibers that may fall off. In addition, the adhesive reliability is sufficiently excellent. Therefore, by using the composite of the present invention as a material for an insulating substrate, a printed wiring board having excellent reliability can be manufactured.

  When the storage elastic modulus at 25 ° C. of the cured product of the curable resin composition is less than 100 MPa, handleability and dimensional stability are lowered, and sufficient adhesion reliability cannot be obtained. If it exceeds, the cured resin becomes brittle, and thus generation of resin powder or fibers that may fall off cannot be sufficiently suppressed.

  In the composite of the present invention, the curable resin composition preferably contains a viscoelastic resin. Such a composite is more reliably suppressed from generating resin powder or fibers that may fall off, and has sufficiently excellent adhesion reliability.

  Further, in the composite of the present invention, the curable resin composition contains an acrylic polymer having a weight average molecular weight of 30000 or more, and the acrylic polymer contains 2 to 20% by mass of glycidyl acrylate as a polymerization component, The epoxy value is preferably 2 to 36. In addition, the value calculated | required by the HLC measuring method is employ | adopted for an epoxy value.

  When the weight average molecular weight of the acrylic polymer is less than 30000, the flexibility tends to decrease. Further, if the glycidyl acrylate contained as a polymerization component in the acrylic polymer is less than 2% by mass, the glass transition temperature Tg of the cured product tends to be lowered and the heat resistance tends to be insufficient, whereas 20% by mass. If it exceeds 1, the storage elastic modulus of the cured product tends to increase and the generation of resin powder or fibers cannot be sufficiently suppressed. Further, when the epoxy value of the acrylic polymer is less than 2, the glass transition temperature Tg of the cured product tends to be lowered and the heat resistance tends to be insufficient, whereas when it exceeds 36, the storage elasticity of the cured product is decreased. The rate tends to increase and the generation of resin powder or fibers cannot be sufficiently suppressed.

  Furthermore, in the composite of the present invention, the fiber sheet is preferably a glass cloth having a thickness of 10 to 200 μm. According to such a composite, it is possible to obtain an insulating substrate that has sufficient mechanical strength and can easily increase the density of the printed wiring board.

  In the composite of the present invention, the total thickness of the composite is preferably 100 μm or less. When the total thickness of the composite is 100 μm or less, it is easier to increase the density when used as an insulating substrate constituting the printed wiring board.

  Furthermore, in the composite of the present invention, the composite preferably has a through hole. According to such a composite, the step of forming the through-hole can be omitted by providing the through-hole in advance at a predetermined position. By using such a composite, a printed wiring board having an IVH structure excellent in reliability can be obtained. It can be manufactured with good yield.

  The prepreg of the present invention is characterized in that, in the composite of the present invention, the curable resin composition is semi-cured.

  By using the curable resin composition described above, the prepreg of the present invention is sufficiently suppressed in the generation of resin powder or fibers that may fall off and has sufficiently excellent adhesion reliability. Yes. Therefore, when manufacturing the printed wiring board which has IVH structure using the prepreg of this invention, the printed wiring board excellent in reliability can be obtained.

  Furthermore, the prepreg of the present invention preferably has a through hole. According to such a prepreg, the step of forming the through-hole can be omitted by providing the through-hole in a predetermined position in advance, and by using such a prepreg, a printed wiring board having an excellent IVH structure can be more easily obtained. Can be manufactured.

  Further, the first metal foil-clad laminate of the present invention is a composite of the present invention having a through hole, in which the through hole is filled with a conductor and a metal foil is disposed on at least one surface of the composite, It is obtained by heating and pressing.

  By using the composite of the present invention, such a metal foil-clad laminate is sufficiently suppressed from falling off the resin powder or fibers from the metal foil-clad laminate and has sufficiently excellent adhesion reliability. is doing. Therefore, when manufacturing the printed wiring board which has IVH structure using the metal foil tension laminated board of this invention, the printed wiring board excellent in reliability can be obtained with a sufficient yield.

  Further, the second metal foil-clad laminate of the present invention is a prepreg of the present invention having a through-hole, in which a through-hole is filled with a conductor and a metal foil is disposed on at least one surface of the prepreg. It is obtained by pressing.

  Such a metal foil-clad laminate has a sufficiently excellent adhesion reliability while sufficiently preventing the resin powder or fibers from falling off the metal foil-clad laminate by using the prepreg of the present invention. ing. Therefore, when manufacturing the printed wiring board which has IVH structure using the metal foil tension laminated board of this invention, the printed wiring board excellent in reliability can be obtained with a sufficient yield.

  In addition, the printed wiring board of the present invention includes a first base material composed of the composite of the present invention, a first thermosetting resin layer formed on both surfaces of the first base material, A circuit electrode patterned on a surface layer of the first thermosetting resin layer, and a first through hole penetrating the first base material and the first thermosetting resin layer is formed. And using at least two double-sided printed wiring boards in which the first through hole is filled with a conductive material for electrically connecting the circuit electrodes on both surfaces to each other, and the two double-sided printed wiring boards Between the second base material made of the composite and the second thermosetting resin layer formed on both surfaces of the second base material, and the second base material, A second through hole penetrating the second thermosetting resin layer is formed, and the second through hole is filled with a conductive material. And a third substrate formed on at least one surface of the double-sided printed wiring board and the third substrate made of the composite, and a third substrate formed on both surfaces of the third substrate. And a circuit electrode patterned on the surface of one of the third thermosetting resin layers, the third base material and the third thermosetting resin layer. A single-sided printed wiring board in which a third through-hole penetrating is formed and the third through-hole is filled with a conductive substance is laminated so that the circuit electrode of the single-sided printed wiring board is on the outside. It is characterized by being.

  The configuration of the conventional printed wiring board as described above has the following problems. 1stly, in the structure of the conventional glass epoxy multilayer board | substrate, it is mentioned that the process of the through-hole after multilayer board lamination is not easy. This is because finer hole processing is required to cope with future high-density wiring, and it is difficult to accurately drill holes in the inner layer wiring. For fine hole drilling, drill diameters that are increasingly smaller will be required in the future, and the drilling cost due to this will not be negligible. Moreover, with a fine drill, accurate drilling is expected to be more difficult in the thickness direction. In addition, while the positioning accuracy of the inner layer wiring and the outer layer wiring is increasingly increased, it is becoming difficult to drill a hole at an accurate position due to dimensional deviation of the substrate material and variation in elongation. This makes it difficult to align the inner layers as the number of layers increases. Due to the above-mentioned problems, the number of through-hole connections that can be formed per unit area and circuit pattern density are limited in conventional circuit forming substrates, and high-density mounting will continue to increase in demand in the future. It is difficult to realize a multilayer board for industrial use.

  On the other hand, an important point in achieving high density is to obtain a substrate that can be connected to each inner layer in the case of a multilayer substrate, and in the case of a double-sided substrate, a connection method that does not have through holes is required. It is said. However, even the inner via multilayer substrate as described above has many problems such as a step on the substrate surface, heat resistance, and electrode adhesion strength in the case of the multilayer substrate in the conventional method. Further, in the case of a double-sided substrate, since a hole is drilled after copper foil bonding, connection by plating is required to flatten the substrate surface.

  That is, by forming a via filling with a conductive paste and further combining the printed circuit board with a double-sided printed circuit board that is then bonded to a copper foil, an IVH connection that connects only the respective layers is made possible, and high reliability and It is required to realize a high-quality printed circuit board.

  According to the printed wiring board of the present invention, the first thermosetting resin layer exists on both surfaces of the first base material, and the circuit electrode is patterned on the surface layer of the first thermosetting resin layer. And a first through hole penetrating the first base material and the first thermosetting resin layer is formed, and the circuit electrodes on both surfaces are electrically connected to the first through hole. By filling the conductive material for connection to the via, filling the vias with conductive paste, and then combining the printed circuit board with the double-sided printed circuit board that is then bonded to the copper foil, only between each layer By making IVH connection possible, it is possible to realize a high-reliability and high-quality double-sided printed circuit board. Further, according to the configuration of the printed wiring board of the present invention, it is possible to achieve IVH connection, and it is possible to realize a multilayer wiring printed board having high reliability and high quality.

  Here, in the printed wiring board of the present invention, the conductive substance is preferably a conductive resin paste, and the conductive material in the conductive resin paste is at least one selected from silver, copper, and alloys thereof. It is preferable to include a powder made of metal. Furthermore, the main component of the first to third thermosetting resin layers is preferably an epoxy resin.

  In addition, the method for producing a printed wiring board of the present invention includes a release film in which a thermosetting resin coating layer is formed by applying a thermosetting resin on one side in advance on both surfaces of a base material made of the composite of the present invention. Is placed so that the thermosetting resin coating layer is on the substrate side, and is bonded by applying pressure at a temperature lower than the curing temperature of the thermosetting resin to form the thermosetting resin layer. A through hole is formed at a desired position of the substrate to which the mold film is bonded, and the conductive resin paste is filled up to the release film surface in the through hole, leaving the thermosetting resin on the substrate surface. Then, only the release films on both sides are peeled off, a copper foil is disposed on the surface of the substrate after peeling, and the thermosetting resin is cured by heating and pressing to adhere the copper foil, and the substrate Fewer steps to pattern the surface copper foil Characterized in that it has also.

  According to this manufacturing method, a release film having a fixed thickness of a thermosetting resin coated on one side in advance is prepared on both sides of the base material comprising the composite of the present invention. The mold film is bonded so that the thermosetting resin coating layer is on the inside. At this time, a pressure is applied at a temperature equal to or lower than the curing temperature of the thermosetting resin applied on the release film, and the films are bonded. Next, a through hole is formed at a desired position of the substrate to which the release film coated with the thermosetting resin is bonded, and the through hole is filled to the release film surface using a conductive resin paste. . At this time, the outer release film functions as a protective film for preventing the conductive paste from adhering to portions other than the through holes. Next, only the release films on both sides are peeled while leaving the thermosetting resin on the substrate surface. Thereby, an adhesive layer for obtaining adhesion between the via conductor for obtaining electrical connection on both sides and the copper foil on the surface of the substrate can be formed. Thereafter, a copper foil is disposed on the surface of the peeled substrate, and the thermosetting resin layer can be cured and bonded to the copper foil by heating and pressing. Furthermore, by patterning the copper foil on the surface of the base material by an etching method, a double-sided printed wiring board can be obtained efficiently and rationally.

  In the present invention, after producing a printed wiring board by the method for producing a printed wiring board of the present invention, the release film is peeled off on both surfaces of the printed wiring board in the method for producing a printed wiring board of the present invention. An uncured substrate having a thermosetting resin coating layer in an uncured state is placed, the printed wiring board is sandwiched, a copper foil is disposed on the surface of the uncured board, and heated and pressed, and the printed wiring Provided is a printed wiring board manufacturing method in which a multilayer wiring is formed by performing a process of forming a circuit by laminating and curing a substrate and the uncured substrate and patterning the copper foil on the surface at least once.

  According to this manufacturing method, the printed wiring board produced by the same method as described above is sandwiched between the base material having the uncured resin layer from which the release film prepared separately is peeled, and copper is further provided on the surface. At least once a process of laminating and curing the printed wiring board and the uncured substrate having the uncured thermosetting resin coating layer and forming a circuit by patterning the copper foil on the surface is performed by placing the foil and heating and pressing. By performing the above, a multilayer wiring can be obtained efficiently and rationally.

  The present invention further includes a printed wiring board produced by the method for producing a printed wiring board of the present invention, and an uncured thermosetting obtained after the release film is peeled in the method for producing a printed wiring board of the present invention. An uncured substrate having a mold resin coating layer is alternately disposed in a desired number so that the printed wiring board is always the outermost layer, and heated and pressed to laminate and cure the printed wiring board and the uncured substrate. Accordingly, a method of manufacturing a printed wiring board is provided which forms a multilayer wiring.

  Similarly to this manufacturing method, the cured printed wiring board is always the first to the uncured substrate having the uncured thermosetting resin coating layer from which the release film has been peeled off by the above-described method and the double-sided substrate. Even if the desired number of layers are alternately arranged so as to form an outer layer, and heated and pressed to laminate and cure the printed wiring board and the uncured board, a multilayer wiring can be obtained efficiently and rationally.

  By using a base material sandwiched between release films having a thermosetting resin layer in this way, and using a base material having a structure in which a conductive paste is embedded in the through holes up to the release film surface, A double-sided printed board having an IVH structure having excellent surface smoothness can be obtained. In addition, a double-layer printed board having an IVH structure excellent in surface smoothness can be used to easily make a high-layer board. According to this method, since the copper foil can be bonded after filling the via conductor, it is not necessary to form the copper electrode layer by plating, which is advantageous for the global environment.

  Further, since a hardened base material is used, there is no unnecessary reaction between the via conductor and the laminated base material, and a stable interlayer connection resistance and its reliability can be obtained. Further, the thermosetting resin layer on the surface of the base material contributes to the adhesion between the copper foil and the base material, and a strong adhesion strength is obtained.

  In the method for producing a printed wiring board of the present invention, the conductive material in the conductive resin paste preferably includes a powder made of at least one metal selected from silver, copper, and alloys thereof. The through hole is preferably formed by a drilling method or a laser processing method. Furthermore, the main component of the thermosetting resin coating layer is preferably an epoxy resin.

  ADVANTAGE OF THE INVENTION According to this invention, the composite_body | complex which is excellent in adhesion reliability and generation | occurrence | production of the resin powder or fiber which may drop | omit is fully suppressed can be provided. Moreover, according to this invention, the prepreg using this composite_body | complex and a sheet | seat with metal foil can be provided. Further, according to the present invention, it is possible to form an IVH connection that connects only the respective layers by combining the double-sided printed board that forms the via filling with the conductive paste and then adheres to the copper foil and the printed board. It is possible to realize a high-reliability and high-quality printed wiring board. Furthermore, according to this invention, the manufacturing method of the printed wiring board which can obtain the printed wiring board of the said invention efficiently and rationally can be provided.

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

  First, an embodiment of the composite of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing one embodiment of the composite of the present invention. A composite 100 in FIG. 1 is formed by impregnating a curable resin composition 102 into a fiber sheet 101. The composite 100 includes a through hole 103.

  Examples of the fiber sheet 101 include heat resistant synthetic fibers such as paper, glass cloth such as glass fiber woven fabric and glass fiber nonwoven fabric, and aramid nonwoven fabric. Among these, a glass fiber woven fabric and a glass fiber nonwoven fabric are preferable, and a glass fiber woven fabric is particularly preferable. Examples of the glass material include E glass, S glass, and D glass. Moreover, about the weaving method of the fiber when using a woven fabric as a fiber sheet, a plain weave, satin weave, twill weave, etc. are mentioned, for example.

  About the thickness of a fiber sheet, if the fiber sheet has sufficient intensity | strength, the thinner one is preferable. Specifically, for example, the thickness is preferably 10 to 200 μm, and more preferably 15 to 80 μm. The fiber sheet is preferably one having a smaller linear expansion coefficient.

  The curable resin composition 102 only needs to have a storage elastic modulus at 25 ° C. of 100 to 2000 MPa of the cured product, and includes, for example, a curable resin and a curing agent that cures the curable resin. Things. As the resin component of the curable resin, it is preferable to use a viscoelastic resin, and examples thereof include epoxy resins, rubber-modified epoxy resins, SBR, NBR, CTBN, acrylic resins, polyamides, polyamideimides, and silicone-modified polyamideimides. . Examples of the curing agent include dicyandiamide, phenol resin, imidazole, amine compound, acid anhydride and the like.

  Moreover, the curable resin composition 102 can contain a predetermined solvent. Solvents include aromatic hydrocarbon solvents such as benzene, toluene, xylene, and trimethylbenzene; ether solvents such as tetrahydrofuran; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; glycol ethers such as methyl cellosolve and diethylene glycol. Solvents; ester solvents such as methyl cellosolve acetate; dialkyl glycol solvents such as ethylene glycol dimethyl ether; amide solvents such as N-methylpyrrolidone, N, N′-dimethylformamide, N, N′-dimethylacetamide; methanol, butanol , Alcohol solvents such as isopropanol; ether alcohol solvents such as 2-methoxyethanol and 2-butoxyethanol can be used, and one or more of these can be used. It is possible.

  In the present embodiment, it is preferable to use a combination of a curable acrylic polymer and a curing agent that cures the acrylic polymer as the curable resin composition. In this case, it is preferable to use the curing agent in a proportion of 60 to 350 parts by mass with respect to 100 parts by mass of the acrylic polymer. When the curing agent is less than 60 parts by mass with respect to 100 parts by mass of the acrylic resin, the storage elastic modulus of the cured product tends to be less than 300 MPa, the handleability is lowered, and the Tg of the cured product is lowered, resulting in a high temperature. There is a tendency that problems such as dimensional shrinkage due to deterioration during standing and a decrease in solder heat resistance are likely to occur. On the other hand, when the ratio of the curing agent exceeds 350 parts by mass, the storage elastic modulus of the cured product tends to exceed 2000 MPa. In this case, the cured product becomes brittle, and thus the resin powder or fibers tend to fall off.

  The acrylic polymer preferably has a weight average molecular weight (Mw) of 30000 or more. Further, the acrylic polymer has 2 to 20% by mass of glycidyl acrylate as a polymerization component in the polymer. The epoxy value is preferably 2 to 36.

  Examples of the method for producing the composite 100 include a method in which a fiber sheet is impregnated with a curable resin composition and dried, and then a through hole is formed at a predetermined position. Examples of the method of impregnating the fiber sheet with the curable resin composition include, for example, a method of immersing the fiber sheet in a resin composition solution such as a wet method and a dry method, and a method of applying the curable resin composition to the fiber sheet. Etc.

  Next, a preferred embodiment of the prepreg of the present invention will be described.

  FIG. 2 is a schematic cross-sectional view showing an embodiment of the prepreg of the present invention. A prepreg 200 shown in FIG. 2 includes a fiber sheet 201 and a semi-cured resin composition layer 202 obtained by semi-curing a curable resin composition impregnated in the fiber sheet 201. Further, the prepreg 200 includes a through hole 203.

  The prepreg 200 can be obtained by semi-curing the curable resin composition 102 in the composite 100 described above. In this case, the fiber sheet 201 is the same as the fiber sheet 101, and the semi-cured resin composition layer 202 is obtained by semi-curing the curable resin composition 102. As another method, the prepreg 200 is prepared by impregnating the above curable resin composition into the above fiber sheet and drying, and then semi-curing the curable resin composition to obtain a semi-cured resin composition. It can also be obtained by forming the through hole 203 at a predetermined position after forming the physical layer 202.

  Examples of the method for semi-curing the curable resin composition include methods such as heating, ultraviolet irradiation, and electron beam irradiation. Examples of the conditions for semi-curing by heating include conditions of 100 to 200 ° C. and 1 to 30 minutes.

  In the prepreg of this embodiment, it is preferable that the curing rate of the curable resin composition be in the range of 10 to 70%. When the curing rate of the curable resin composition is less than 10%, when integrated with the metal foil, the unevenness of the fiber sheet is reflected on the surface of the integrated metal foil, and the surface smoothness tends to be reduced. The control of the thickness of the insulating substrate tends to be difficult. On the other hand, when the curing rate of the curable resin composition exceeds 70%, the resin component is insufficient when it is integrated with the metal foil, and when it is integrated at a high speed, bubbles and blurring are likely to occur, and adhesion with the metal foil. Power tends to be insufficient.

  Next, an embodiment of the metal foil-clad laminate of the present invention will be described.

  FIG. 3 is a schematic cross-sectional view showing an embodiment of the metal foil-clad laminate of the present invention. A metal foil-clad laminate 300 shown in FIG. 3 includes an insulating substrate 301 having a through hole 303, a conductor 304 filled in the through hole 303, and a conductor layer 302 stacked on the insulating substrate 301. Has been.

  Examples of the conductor layer 302 include metal foil such as copper foil, aluminum foil, and nickel foil. In the metal foil-clad laminate of this embodiment, the conductor layer 302 is preferably a copper foil, and the thickness is preferably 1 to 70 μm. Moreover, electrolytic copper foil, rolled copper foil, etc. can be used for copper foil. In the metal foil-clad laminate of this embodiment, the conductor layer 302 may be a film having conductivity, and other than the above metal foil, for example, a metal, an organic substance, and a composite thereof may be used. Good.

  Examples of the conductor 304 include a heat-pressed one of a conductive paste containing a metal such as gold, silver, nickel, copper, platinum, palladium, ruthenium oxide, a metal oxide, an organometallic compound, or the like.

  The insulating substrate 301 having the through hole 303 is formed using the composite 100 or the prepreg 200 described above.

  For example, when the metal foil-clad laminate 300 is obtained using the prepreg 200, first, the conductive paste is filled into the through holes 203 of the prepreg 200. Next, a metal foil as a conductor layer is arranged on the surface of the prepreg 200, and the metal foil and the prepreg can be integrated to manufacture the metal foil-clad laminate 300. Further, even if the composite 100 is used instead of the prepreg 200, the metal foil-clad laminate 300 can be similarly manufactured.

  Examples of the method for integrating the metal foil with the prepreg or the composite include metallization, press lamination method, and hot roll continuous lamination method. In the present embodiment, it is preferable to use a press lamination method from the viewpoint of efficiently forming the conductor layer 302. Examples of the heating and pressing conditions for integrating the metal foil and the prepreg or the composite by the press lamination method include a temperature of 120 to 230 ° C., a pressure of 1.0 to 6.0 MPa, and a heating time of 30 to 120 minutes. The conditions of the range are mentioned.

  Further, before continuously laminating the metal foil and the prepreg or the composite, the same photosensitive resin composition as that contained in the prepreg or the composite is applied to the surface of the metal foil, and the resin composition It is preferable to form a layer. Thereby, it can further reduce that the unevenness | corrugation of the surface of the fiber sheet contained in a prepreg or a composite_body | complex is reflected in the surface of a conductor layer.

  Next, preferred embodiments of the printed wiring board and the manufacturing method thereof according to the present invention will be described.

  4A to 4F are a series of process diagrams showing a first embodiment of a method for manufacturing a printed wiring board according to the present invention. First, as shown in FIG. 4 (a), a thermosetting resin is applied to a release film 1 such as a polyester film and dried to remove the solvent, thereby thermosetting the release film 1. A mold resin coating layer 2 is formed.

  Here, the thickness of the releasable film 1 is preferably 3 to 50 μm.

  Further, as the thermosetting resin, not only the thermosetting resin of the present invention but also a resin having heat resistance equivalent to FR-5 whose main component is an epoxy resin can be selected. In addition, a doctor blade method or a method using a coater is effective as a thermosetting resin coating method, but a doctor blade method is preferable. Furthermore, the thickness of the thermosetting resin coating layer 2 after drying is preferably 10 to 60 μm.

  Next, as shown in FIG. 4B, the thermosetting resin coating layer 2 and the release film 1 are arranged on both surfaces of the base material 3.

  Here, the base material 3 consists of the composite_body | complex of this invention mentioned above, for example, can be obtained by pinching | interposing a composite body with a heat-resistant release film, thermosetting, and peeling a heat-resistant release film. . In addition, the base material 3 may consist of a prepreg mentioned above. Moreover, it is preferable that the thickness of the base material 3 is 10-700 micrometers.

  The release film 1 on which the thermosetting resin coating layer 2 is formed is attached to both surfaces of the base material 3 thus produced. The pasting is performed by applying pressure at a temperature equal to or lower than the curing temperature of the thermosetting resin applied on the release film 1. For example, when the curing start temperature of the thermosetting resin is about 130 ° C., pressurization can be performed at a temperature of about 105 ° C. and a pressure of about 2 MPa. Thereby, the thermosetting resin coating layer 2 is slightly softened and contributes to the adhesion between the substrate 3 and the release film 1. At this time, if the adhesive strength between the release film 1 and the substrate 3 is too weak, there is a risk of peeling in the subsequent hole processing, and if it is too strong, the release film cannot be peeled off. It is necessary to adjust to.

  Next, as shown in FIG.4 (c), the through-hole 4 is formed in the predetermined location of the base material 3 after the release film 1 adhesion | attachment using a laser processing method, a drill processing method, etc., and the through-hole 4 is filled with the conductive paste 5.

  As a method of filling the conductive paste 5, for example, the base material 3 having the through holes 4 is placed on a table of a printing machine (not shown), and the conductive paste 5 is directly applied from the release film 1. The method of printing is mentioned. At this time, the release film 1 on the upper surface plays a role of a printing mask and a prevention of contamination of the surface of the substrate 3.

  In addition, as the conductive paste to be used, metal powder such as silver powder, copper powder and alloy powder thereof is used as the conductive filler, and this is dispersed in the above-described curable resin composition such as epoxy resin and its curing agent. The thing which becomes.

  Next, as shown in FIG. 4 (d), only the release film 1 is peeled off from the base material 3 after filling the conductive paste 5 so that the thermosetting resin layer 2 remains on the surface of the base material 3. .

  Next, a single-side roughened metal foil (circuit electrode) 6 whose one side has been roughened is laminated and pressure-bonded as shown in FIG.

  As this metal foil, copper foil etc. are used, for example, and it is preferable that the thickness is 1-35 micrometers.

  The pressure bonding is performed by applying a predetermined pressure at a temperature at which the thermosetting resin in the thermosetting resin coating layer 2 is cured (for example, at 170 ° C. for 1 hour in a vacuum), whereby the thermosetting type is applied. The resin is cured and the metal foil is adhered.

  Thereafter, as shown in FIG. 4 (f), the copper foil is patterned by a photolithography method (dry film resist laminate DFR, ultraviolet curing, DFR development, etching, DFR peeling) which is a well-known technique. Thereafter, solder resist formation, character formation, substrate processing, and the like are performed as necessary to obtain a double-sided printed wiring board.

  The double-sided printed wiring board manufactured in this way has an IVH structure, and can obtain high reliability and high quality.

  Next, a second embodiment of the method for manufacturing a printed wiring board of the present invention will be described. FIGS. 5A to 5B are a series of process diagrams showing a second embodiment of the method for manufacturing a printed wiring board of the present invention. In the method for manufacturing a printed wiring board according to the second embodiment, a multilayer printed wiring board is produced using the double-sided printed wiring board shown in the first embodiment.

  First, a method for producing a double-sided board for an inner layer is similar to the first embodiment, in which a thermosetting resin is applied to a polyethylene terephthalate releasable film 1 and dried to remove a solvent, and then a thermosetting resin coating layer is formed. 2 is formed.

  Next, the release film 1 and the thermosetting resin coating layer 2 are arranged on both surfaces of the base material 3 in the same manner as in the first embodiment, and are adhered. As the base material 3, a material obtained by curing the composite or prepreg of the present invention described above is used. In addition, as the base material 3, you may use what laminated | stacked and hardened the some composite_body | complex or prepreg.

  Thus, the produced base material 3 and the release film 1 which apply | coated the said thermosetting resin are bonded together. The bonding condition is performed by pressurizing at a temperature equal to or lower than the curing temperature of the thermosetting resin applied to the release film 1 as described above.

  Next, the through-hole 4 is formed in the predetermined location of the base material 3 after the release film 1 is bonded using a drilling method. The through-hole 4 is filled with the conductive paste 5. As a method of filling the conductive paste 5, the base material 3 having the through holes 4 is set on a table of a printing machine (not shown), and the conductive paste 5 is directly printed from the release film 1. . At this time, the printed lower surface is vacuum-sucked through the sintered metal, and paper is placed between the base material 3 and the sintered metal so that the paste is sucked and not taken into the sintered metal. Moreover, the release film 1 on the upper surface plays a role of a printing mask and a prevention of contamination of the surface of the substrate 3.

  Only the release film 1 is peeled off from the base material 3 filled with the conductive paste 5 as in the first embodiment. The product thus produced is sandwiched between the two-sided roughened metal foils 6 whose surfaces have been roughened and laminated and pressure-bonded. Thereby, the thermosetting resin coating layer 2 on the surface of the base material 3 is cured and bonded, and the metal foil 6 and the base material 3 are joined. A circuit pattern is formed by a photolithography method on the metal foil-clad laminated base material thus produced in order to form wiring.

  Using the double-sided printed wiring board produced as described above as an intermediate material for inner layer wiring, a multilayer wiring board is produced. First, apart from the above-mentioned double-sided printed wiring board, the state shown in FIG. 4 (d) in which the through-hole 4 of the base material 3 is filled with the conductive paste 5 in the same manner as described above and the release film 1 is peeled off. Prepare an intermediate plate.

  And as shown to Fig.5 (a), an intermediate board is arrange | positioned on both surfaces of a double-sided printed wiring board, and also the single-side roughening metal foil (circuit electrode) 7 is arrange | positioned on the outer side of an intermediate board. These are heated and pressed in the directions of arrows A and B to be laminated and integrated. The conditions of heating and pressing at the time of lamination are the same as the conditions at the time of laminating the single-side roughened metal foil (circuit electrode) 6 at the time of producing the double-sided printed wiring board.

  Thereafter, in order to form wiring, a circuit pattern is formed by photolithography, and a four-layer printed wiring board is produced as shown in FIG.

  The four-layer printed wiring board manufactured in this way has an IVH structure, and can obtain high reliability and high quality.

  Although a method for manufacturing a four-layer printed wiring board has been described here, a six-layer printed wiring board or a higher multi-layered wiring board can be obtained by further combining and stacking intermediate plates and performing patterning. . At this time, the metal foil other than the outermost layer is preferably a double-side roughened copper metal foil.

  Next, a third embodiment of the method for manufacturing a printed wiring board of the present invention will be described. 6A to 6B are a series of process diagrams showing a third embodiment of the method for manufacturing a printed wiring board of the present invention. In the method for manufacturing a printed wiring board according to the third embodiment, a multilayer printed wiring board is manufactured using the double-sided printed wiring board and the intermediate plate shown in the second embodiment.

  That is, as shown in FIG. 6A, two double-sided printed wiring boards and three intermediate plates are alternately arranged, and one-side roughened metal foil (circuit electrode) 7 is further arranged as the outermost layer. Then, lamination and patterning are performed. In the lamination, the metal foil is bonded by heating and pressurizing in the directions of arrows A and B by hot pressing (for example, in a vacuum at 170 ° C. and 4 MPa for 1 hour). For patterning after adhesion of the metal foil, a wiring pattern is formed by photolithography. Thereby, a 6-layer printed wiring board having the structure shown in FIG. 6B can be obtained.

  The six-layer printed wiring board manufactured in this way has an IVH structure, and can obtain high reliability and high quality.

  The printed wiring board of the present invention is manufactured by the method for manufacturing a printed wiring board of the present invention described above, and has, for example, a configuration as shown in FIG.

  The printed wiring board of the present invention having such a configuration has an IVH structure and can obtain high reliability and high quality.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the composite of the present invention. FIG. 2 is a schematic cross-sectional view showing an embodiment of the prepreg of the present invention. FIG. 3 is a schematic cross-sectional view showing an embodiment of the metal foil-clad laminate of the present invention. (A)-(f) is a series of process drawings which show 1st Embodiment of the manufacturing method of the printed wiring board of this invention. (A)-(b) is a series of process drawings which show 2nd Embodiment of the manufacturing method of the printed wiring board of this invention. (A)-(b) is a series of process drawings which shows 3rd Embodiment of the manufacturing method of the printed wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Composite, 101 ... Fiber sheet, 102 ... Curable resin composition, 103, 203, 303 ... Through-hole, 200 ... Pre-preg, 201 ... Fiber sheet, 202 ... Semi-cured resin composition layer, 300 ... Metal foil tension Laminated plate, 301 ... insulating substrate, 302 ... conductor layer, 304 ... conductive portion.

Claims (14)

A composite comprising a fiber sheet impregnated with a curable resin composition,
The composite whose storage elastic modulus in 25 degreeC of the hardened | cured material of the said curable resin composition is 100-2000 Mpa.   The composite according to claim 1, wherein the curable resin composition contains a viscoelastic resin.   The curable resin composition contains an acrylic polymer having a weight average molecular weight of 30000 or more, and the acrylic polymer contains 2 to 20% by mass of glycidyl acrylate as a polymerization component and has an epoxy value of 2 to 36. The complex according to claim 1 or 2.   The composite according to any one of claims 1 to 3, wherein the fiber sheet is a glass cloth having a thickness of 10 to 200 µm.   The composite according to any one of claims 1 to 4, wherein the total thickness of the composite is 100 µm or less.   The composite according to any one of claims 1 to 5, which has a through-hole.   The composite according to any one of claims 1 to 5, wherein the curable resin composition is semi-cured.   The prepreg of Claim 7 which has a through-hole.   The metal foil-clad laminate obtained by heating and pressurizing the composite according to claim 6, wherein the through-hole is filled with a conductor and a metal foil is disposed on at least one surface of the composite.   The prepreg according to claim 8, wherein the metal foil-clad laminate is obtained by heating and pressing a through-hole filled with a conductor and a metal foil disposed on at least one surface of the prepreg. A first base material comprising the composite according to any one of claims 1 to 5, a first thermosetting resin layer formed on both surfaces of the first base material, A circuit electrode patterned on a surface layer of one thermosetting resin layer, and a first through hole penetrating the first base material and the first thermosetting resin layer is formed. , Using at least two double-sided printed wiring boards in which the first through hole is filled with a conductive substance for electrically connecting the circuit electrodes on both surfaces,
Between the two double-sided printed wiring boards, a second base material made of the composite, and a second thermosetting resin layer formed on both surfaces of the second base material A second through-hole penetrating the second base material and the second thermosetting resin layer is formed, and an intermediate plate is formed by filling the second through-hole with a conductive substance. While being pinched,
On at least one surface of the double-sided printed wiring board, a third base material made of the composite, a third thermosetting resin layer formed on both surfaces of the third base material, and the first base material And a circuit electrode patterned on the surface layer of the thermosetting resin layer 3, and a third through hole penetrating the third base material and the third thermosetting resin layer is formed. A printed wiring board in which a single-sided printed wiring board in which the third through-hole is filled with a conductive substance is laminated so that the circuit electrode of the single-sided printed wiring board is on the outside.   A release film in which a thermosetting resin coating layer is formed on one side in advance by applying a thermosetting resin coating on both sides of the base material composed of the composite according to any one of claims 1 to 5, Place the curable resin coating layer on the substrate side, apply pressure at a temperature not higher than the curing temperature of the thermosetting resin, and attach the release film on which the thermosetting resin layer is formed. A through hole is formed at a desired position of the combined base material, and the through hole is filled with a conductive resin paste up to the surface of the release film, and the thermosetting resin is left on the base material surface, and the both sides Only the release film is peeled off, a copper foil is disposed on the surface of the substrate after peeling, and the thermosetting resin is cured by heating and pressing to adhere the copper foil, and the copper foil on the surface of the substrate At least a patterning step Method of manufacturing a substrate.   After producing a printed wiring board by the manufacturing method of Claim 12, it is the thermosetting of an unhardened state obtained after peeling a release film in the manufacturing method of Claim 12 on both surfaces of the said printed wiring board. An uncured substrate having a mold resin coating layer is arranged, the printed wiring board is sandwiched, a copper foil is disposed on the surface of the uncured substrate, and heated and pressed to laminate the printed wiring board and the uncured substrate. A method for producing a printed wiring board, wherein a multilayer wiring is formed by performing a step of curing and patterning the copper foil on the surface to form a circuit at least once. A printed wiring board produced by the manufacturing method according to claim 12 and an uncured substrate having an uncured thermosetting resin coating layer obtained after peeling the release film in the manufacturing method according to claim 12. And alternately arranging a desired number so that the printed wiring board is always the outermost layer, and forming the multilayer wiring by stacking and curing the printed wiring board and the uncured board by heating and pressurization, A method for manufacturing a printed wiring board.

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