JP2006165242A - Printed-wiring board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed-wiring board fitted to a high-density mounting by completely burying a via hole with a metal plating in the multilayer printed-wiring board widely used for various electronic equipment. <P>SOLUTION: A copper foil 4 with a resin is laminated on an internal layer material with a conductor pattern 2, the copper foil is removed, a non-through-hole is formed by a laser machining, and a via 7 is obtained by completely burying the non-through-hole by repeating the metal plating. A land 9 on a conductor pattern 8 for an external layer and the via 7 is formed by using a means such as a screen printing method, a photographing method on a surface, and the multilayer printed-wiring board 10 shown in Fig. (d) is manufactured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a multilayer printed wiring board that is widely used in various electronic devices for industrial use and consumer use.

  In recent years, with the spread of personal computers, word processors, video-integrated cameras, mobile phones, etc., the demand for multilayer printed wiring boards has been increasing. Reasons for making these electronic devices smaller, lighter, multifunctional, etc. Therefore, multilayer printed wiring boards have started to require interstitial via holes (hereinafter referred to as IVH), which is an interlayer electrical connection method using non-through via holes to further improve wiring accommodation and surface mounting density. Yes.

  In addition, in order to form a mounting land directly above the conduction hole in order to increase the component mounting density, a conductive paste is filled in the through hole, and copper foil is pressure-bonded and laminated, and then a conductor circuit and a mounting land are formed. After conducting electroplating on printed wiring boards and through-holes or non-through-holes to form conductive holes, filling with conductive paste or resin paste, then electroplating again, and then forming conductor circuits and mounting lands As a result, it is possible to mount components on the through-holes, thereby increasing the number of multilayer printed wiring boards that can improve the mounting density of components and reduce the size and weight of electronic devices.

  Furthermore, as represented by chip size package (CSP) and ball grid array (BGA), the area of soldering terminals of components has been reduced due to the recent increase in the number of pins and the number of terminals of semiconductor components. Land area has also been reduced.

  In addition, the so-called reflow soldering method, in which solder is melted in a high-temperature heat atmosphere from the conventional solder flow method to solder the component and the printed circuit board mounting land, is increasing year by year, and there is a demand for heat resistance of the printed circuit board. It's getting higher.

As a prior art document related to the invention of this application, for example, Patent Document 1 is known.
JP-A-6-268345

  As described above, in the background of component mounting on a printed wiring board, due to the reduction of the mounting land area, the adhesion and peeling strength with the substrate constituting the printed wiring board is reduced, and further soldering in a high temperature atmosphere is reduced. When the component terminals and printed circuit board mounting lands are joined, thermal stress is generated due to dimensional changes, which may cause a force to peel off the adhesion between the mounting lands and the base material. Depending on the environment, the mounting land may be peeled off from the base material.

  The present invention solves the above-mentioned conventional problems, and enables the mounting of parts and the like on through holes or non-through holes, and is capable of withstanding dimensional changes even after component soldering in a high temperature atmosphere. An object of the present invention is to provide a printed wiring board suitable for high-density mounting including a mounting land having strength and a method for manufacturing the same.

  In order to solve this problem, the present invention provides a printed wiring board comprising a step of forming a processed hole in a copper clad laminate comprising a copper foil and an insulating resin layer, and a step of embedding the processed hole by conductive plating. A through hole or non-through hole is formed in a copper clad laminate made of copper foil and an insulating layer using a manufacturing method, and the processed hole is embedded by conductive plating. The printed wiring board which formed the land of this is provided.

  The invention according to claim 1 of the present invention is a printed wiring board in which processed holes are formed in a copper clad laminate made of copper foil and an insulating layer, and the processed holes are embedded by conductive plating. In addition, it has the effect of improving the strength of the processed hole and the conductor in the vicinity of the processed hole.

  The invention according to claim 2 of the present invention is the printed wiring board according to claim 1 in which the processed hole is a through hole, and improves the strength of the through hole and the conductor in the vicinity thereof, It has the effect of improving connective reliability.

  The invention according to claim 3 of the present invention is the printed wiring board according to claim 1 in which the processed hole is a non-through hole, and improves the strength of the non-through hole and a conductor in the vicinity thereof. , It has the effect of improving the electrical connection reliability of the surface layer and the inner layer.

  The invention according to claim 4 of the present invention is the printed wiring board according to claim 1 in which a conductor land for mounting is formed on the processing hole, and includes a processing hole and the vicinity of the processing hole. It has the effect of improving the peel strength, adhesion and heat resistance of the conductor land.

  Invention of Claim 5 of this invention is a printed wiring board of Claim 1 which is a multilayer copper clad laminated board in which a copper clad laminated board has a circuit formation board | substrate in an inner layer, Surface layer and inner layer Or it has the effect | action of improving the intensity | strength of the conduction | electrical_connection hole of both surface layers, and the conductor of the surface layer of the conduction | electrical_connection vicinity, and improving the electrical connection reliability between layers.

  The invention according to claim 6 of the present invention is the printed wiring board according to claim 1 in which a non-through hole for interlayer connection is formed in the multilayer copper-clad laminate described in claim 5. Multi-layer prints that improve the strength of the surface layer and inner layer conduction holes and the surface layer conductors near the conduction holes, improve the electrical connection reliability between the layers, increase the conductor wiring density, and support high-density mounting A wiring board can be provided.

  The invention according to claim 7 of the present invention is the printed wiring board according to claim 5 in which the circuit forming substrate is a multilayer circuit forming substrate, and a conductive hole and a conductive layer between the surface layer and the inner layer or both surface layers. It is possible to provide a high-layer printed wiring board capable of improving the strength of the surface conductor near the hole and improving the electrical connection reliability between the layers.

  The invention according to claim 8 of the present invention is the printed wiring board according to claim 7, wherein the interlayer connection of the multilayer circuit forming substrate is formed by a conduction hole filled with a conductive paste. By connecting the layers with conductive paste, the thickness of the conductor can be reduced, so that the wiring density of the conductor circuit in the inner layer can be improved, and the conductive holes between the surface layer and the inner layer or both surface layers and in the vicinity of the conductive holes It is possible to provide a high-layer printed wiring board capable of improving the strength of the surface conductor and improving the electrical connection reliability between the layers.

  The invention according to claim 9 of the present invention is the printed wiring board according to claim 5, wherein the cross-sectional shape of the non-through hole is an inverted trapezoidal shape, and against thermal expansion in the thickness direction of the laminate. Thus, the strength of the non-through conduction hole is improved, and the heat resistance strength of the conductor land and the mounting reliability at the time of component mounting are improved.

  Invention of Claim 10 of this invention is set as the printed wiring board of Claim 1 formed in the range whose diameter of a process hole is 20-100 micrometers, and embeds a process hole by electroconductive plating. In the case of 20 μm or less, the plating solution hardly penetrates into the processing hole, the plating is poor and the reliability as the conduction hole is poor, and when the processing hole of 100 μm or more is embedded, the conductor thickness of the surface layer is thick, and the conductor It becomes difficult to make the line thinner. Therefore, by setting the diameter of the processed hole in the range of 20 to 100 μm, it is possible to provide a high-density printed wiring board that is highly reliable as a conduction hole and can be thinned.

  Invention of Claim 11 of this invention is set as the printed wiring board of Claim 5 formed in the range whose depth of a non-through-hole is 40-200 micrometers, and a diameter is the range of 20-100 micrometers. By forming the depth in the range of 40 to 200 μm corresponding to the non-through holes, it is possible to maintain a constant aspect ratio (depth / hole diameter) and achieve uniform electrodeposition of plating. And, it has an effect that the reliability of the conduction hole can be stabilized.

  The invention according to claim 12 of the present invention is the printed wiring board according to claim 1 in which the conductive plating is formed of a conductive material different from copper foil, and is a conductive material that forms a conductive hole. It is possible to select according to the required characteristics for mounting the substance, and it is possible to select the etching solution for forming the conductor circuit by etching according to the circuit forming method. .

  The invention according to claim 13 of the present invention is the printed wiring board according to claim 1 in which only the processed hole and the vicinity of the processed hole are formed by gold plating. Soldering property and contact resistance as a contact electrode are minimized, and the other wiring conductors are configured only by copper foil, so that thinning is easy.

  The invention according to claim 14 of the present invention is the printed wiring board according to claim 1, wherein the insulating layer is a base material obtained by impregnating a resin into a woven or non-woven fabric of aromatic polyamide. Since it is suitable for the hole processing by, it can provide a high-density printed wiring board.

  The invention according to the fifteenth aspect of the present invention is the printed wiring board according to the first aspect, wherein the insulating layer is a ceramic material, and can be used for punching holes such as unfired green sheets. It is also possible to provide a printed wiring board that requires high heat resistance and has high adhesion to the conductor lands for mounting.

  The invention according to claim 16 of the present invention is the printed wiring board according to claim 5 in which the conduction hole of the inner-layer circuit forming substrate having a through-hole is filled with a thermosetting resin in advance. Before forming the copper-clad laminate, filling the conductive holes in advance with a thermosetting resin has the effect of reducing voids in heating lamination and variations in plate thickness.

  The invention according to claim 17 of the present invention is the printed wiring board according to claim 1, which is a copper clad laminate comprising copper foil, a metal plate having a surface subjected to insulation treatment, and an insulating layer. Therefore, it is possible to provide a printed wiring board excellent in high-density mounting and heat dissipation.

  The invention according to claim 18 of the present invention is the printed wiring board according to claim 1 in which the processing holes are selectively embedded, and the conductive material consumed by embedding only the necessary processing holes. By reducing the thickness of the conductor for wiring and reducing the thickness of the conductor for wiring, the conductor can be easily thinned, and the printed wiring board can be reduced in weight.

  The invention according to claim 19 of the present invention comprises a step of forming a processed hole in a copper clad laminate made of copper foil and an insulating resin layer, and a step of embedding the processed hole by conductive plating. And a printed wiring board capable of improving the strength of the processed hole and the conductor in the vicinity of the processed hole.

  The invention according to claim 20 of the present invention is the method for manufacturing a printed wiring board according to claim 19, wherein the through hole is provided with a through hole and a conductor in the vicinity thereof. The printed wiring board which can improve the intensity | strength of this and can improve electrical connection reliability can be provided.

  The invention according to claim 21 of the present invention is the method for manufacturing a printed wiring board according to claim 19, wherein a non-through hole is provided, and the non-through hole and its vicinity It is possible to provide a printed wiring board capable of improving the strength of the conductor and improving the electrical connection reliability of the surface layer and the inner layer.

  The invention described in claim 22 of the present invention is the method for manufacturing a printed wiring board according to claim 19, wherein the processing hole is formed by a laser, and a small-diameter processing hole can be formed. A printed wiring board suitable for high-density mounting can be provided.

  The invention described in claim 23 of the present invention is the method for producing a printed wiring board according to claim 22, wherein a carbon dioxide laser having a focal beam diameter of 40 to 120 μm is used. 20 to 100 μm can be realized as the finishing range of the processing hole suitable for the embedding of steel.

  The invention according to claim 24 of the present invention is the method for producing a printed wiring board according to claim 19, wherein the processed hole is treated with an alcohol-based solution after the processed hole is formed. By dissolving and removing foreign matters and deposits in the processed holes, conductive plating is reliably formed on the processed holes, and the reliability of electrical connection as a conductive hole between layers is stabilized.

  The invention according to claim 25 of the present invention is the method for producing a printed wiring board according to claim 19, wherein the copper foil is copper foil with an adhesive resin, and the efficiency of lamination and processing holes are increased. In addition, it has the effect of improving the adhesion of the conductor lands and wiring conductors in the vicinity of the processed holes and further stabilizing the thickness of the copper-clad laminate.

  The invention according to claim 26 of the present invention is the production of a printed wiring board according to claim 19, wherein a copper foil and an insulating resin layer having adhesiveness are laminated and thermocompression bonded to form a copper clad laminate. This is a method that improves adhesion of conductor lands and wiring conductors in the vicinity of processed holes and wiring conductors and prevents delamination, improves lamination reliability, and stabilizes the thickness of copper-clad laminates. It has the effect | action of aiming at conversion.

  The invention according to claim 27 of the present invention is a printed wiring board according to claim 19, wherein the copper foil with adhesive resin and the circuit forming substrate are laminated and heat-pressed to form a multilayer copper-clad laminate. This is a board manufacturing method that improves efficiency in the multi-layer stacking process, improves the adhesion of processed holes and conductor lands in the vicinity of processed holes and wiring conductors, stabilizes the thickness after stacking, and implements high-density mounting. A multilayer printed wiring board suitable for the above is provided.

  The invention according to claim 28 of the present invention includes a step of forming a through hole in an insulating resin base material having adhesiveness, a step of filling the through hole with a conductive paste, and laminating copper foil on both surfaces. 28. The method for producing a printed wiring board according to claim 27, wherein the step of thermocompression bonding and the copper foil on both sides are selectively etched to form a conductor circuit to form a circuit-formed substrate. Easier design by improving efficiency and improving adhesion of conductor lands and wiring conductors in the vicinity of the processing holes and wiring conductors, stabilizing the plate thickness after lamination, and increasing the degree of freedom of arrangement of the conductive holes A multilayer printed wiring board suitable for high-density mounting is also provided.

  The invention according to claim 29 of the present invention is the method for producing a printed wiring board according to claim 28, wherein an aromatic polyamide nonwoven fabric epoxy resin base material is used as the insulating resin base material. In addition, the present invention provides a multilayer printed wiring board suitable for high-density mounting by facilitating laser processability of through holes.

  The invention according to claim 30 of the present invention is the print according to claim 19, wherein the conductive plating layer formed on both sides of the copper clad laminate is polished or etched after embedding the processed hole by conductive plating. This is a method for manufacturing a wiring board. By providing a process for thinning the conductive plating layers on both surfaces of a copper clad laminate, it is possible to easily realize high density and thinning in the formation of conductor circuits. Have.

  The invention according to claim 31 of the present invention is the method for producing a printed wiring board according to claim 30, wherein the conductive plating layer is polished or etched to a thickness in the range of 10 to 30 μm. It has the effect of facilitating the thinning of the conductor circuit while maintaining the connection reliability of the conductor.

  According to the thirty-second aspect of the present invention, after forming the processing hole, the processing hole (and the copper foil surface) is selectively covered with a detachable plating resist, and after the electroplating, the plating is performed. 20. The printed wiring board manufacturing method according to claim 19, wherein the resist is peeled and removed, and the conductive material consumed is reduced by embedding only the necessary processed holes (and the copper foil surface). By reducing the thickness of the conductor, the conductor can be easily thinned, and the printed wiring board can be reduced in weight.

  A thirty-third aspect of the present invention is the method for manufacturing a printed wiring board according to the thirty-second aspect, wherein the conductive plating is performed with a metal different from copper foil, and a conductive substance forming a conductive hole. It is possible to select according to the required characteristics for mounting, and it is possible to select the etching solution for forming the conductor circuit by etching according to the circuit formation method, particularly the etching resist. Is.

  The present invention includes a mounting land that can mount a component or the like on a through-hole or a non-through-hole and has a peel strength that can withstand dimensional changes even after component soldering in a high-temperature atmosphere. A printed wiring board suitable for high-density mounting can be provided by an easy method.

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

(Embodiment 1)
1A to 1E are cross-sectional views showing a method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention. In FIG. 1, 1 is an inner layer material, 2 is a conductor pattern for an inner layer, 3 is an insulating substrate for an inner layer, 4 is copper foil with resin, and 5 is an IVH (metal plated non-through hole formed by laser processing) (Hereinafter referred to as “laser via”), 6 is a through hole for electrically connecting the inner layers, 10 is a multilayer printed wiring board having a conductor pattern inside and outside, 7 is a laser via buried by metal plating, and 8 is a conductor pattern for the outer layer. , 9 are lands provided on the vias.

  A method for manufacturing the multilayer printed wiring board configured as described above will be described below.

  First, as shown in FIG. 1 (a), a copper clad laminate having copper foil laminated on both sides of an insulating substrate 3 is coated with an inner layer conductor by means of screen printing or photographic methods. A pattern 2 is formed to obtain an inner layer material 1 for a multilayer printed wiring board.

  Next, as shown in FIG.1 (b), the copper foil 4 with a resin was laminated to the inner layer material 1 which has the conductor pattern 2 for inner layers formed on the insulating substrate 3, and the copper foil was removed. Then, non-through holes with a hole diameter of 50 μm are formed by laser processing (processing conditions: pulse width 6 μs × 1 time + pulse width 3 μs × 1 time + pulse width 2 μs × 1 time), and further, through holes are formed by drilling or the like. Then, metal plating is performed to obtain a laser via 5 that electrically connects the inner and outer layers and a through hole 6 that electrically connects the inner and outer layers.

  In this embodiment, copper foil with adhesive resin is used. This is because it is possible to improve the efficiency of the lamination, improve the adhesion between the processed holes and the conductor lands in the vicinity of the processed holes and the wiring conductor, and stabilize the thickness of the copper-clad laminate.

  It is also possible to laminate or apply an adhesive insulating resin layer on the inner layer material 1, laminate a copper foil alone or a resin-coated copper foil, and perform thermocompression bonding. It is possible to improve adhesion of conductor lands and wiring conductors in the vicinity of processed holes and wiring holes and prevent delamination, improve lamination reliability, and stabilize the thickness of copper-clad laminates It is.

  In the present embodiment, since a small-diameter processing hole suitable for high-density mounting can be formed, a laser processing method is employed.

  In addition, it is desirable to form the diameter of a non-through-hole in the range of 20-100 micrometers. When embedding a processed hole by conductive plating, if the thickness is 20 μm or less, the plating solution is difficult to penetrate into the processed hole, the plating is poor, and the reliability as a conductive hole is poor, and a processed hole of 100 μm or more is embedded. The surface conductor is thick, making it difficult to thin the conductor. Therefore, by setting the diameter of the processed hole in the range of 20 to 100 μm, the reliability as the conduction hole is high, and the conductor can be thinned. In laser processing, it is desirable to use a carbon dioxide laser having a focal beam diameter of 40 to 120 μm. This is because 20 to 100 μm can be realized as a finishing range of the processing hole suitable for embedding conductive plating in the processing hole.

  The depth of the non-through hole is preferably in the range of 40 to 200 μm. Corresponding to non-through holes with a diameter in the range of 20-100 μm, by forming the depth in the range of 40-200 μm, maintaining a constant aspect ratio (depth / hole diameter) and uniform electrodeposition of plating This is because the reliability of the conduction hole can be stabilized.

  Furthermore, after forming the processing hole, the processing hole is treated with an alcohol-based solution, so that foreign matters and deposits in the processing hole after processing can be dissolved and removed. Plating can be reliably formed, and the reliability of electrical connection as a conduction hole between layers can be stabilized.

  Next, as shown in FIG. 1C, the via 7 is obtained by further filling the laser via 5 with metal plating by repeating metal plating. Thereafter, the outer layer conductor pattern 8 and the land 9 on the via 7 are formed on the surface using means such as a screen printing method or a photographic method to obtain a multilayer printed wiring board 10 as shown in FIG. ing.

  With this configuration, it is possible to improve the peeling strength, adhesion and heat resistance of the processing hole, the conductor in the vicinity of the processing hole, and the conductor land for mounting, and the conduction hole between the surface layer and the inner layer or both surface layers and in the vicinity of the conduction hole. The strength of the surface conductor can be improved, and the electrical connection reliability between the layers can be improved.

  In the above description, the inner layer material has been described as an example of a rigid substrate. However, other synthetic resin substrates, ceramic substrates, metal substrates with surface insulation treatment, and aramid nonwoven fabrics are impregnated with thermosetting resin. Semi-cured to provide through holes, impregnating the through holes with a conductive paste to form an adhesive sheet for interlayer conduction, and conductive foil on both sides of the insulating substrate having holes filled with the conductive paste. It can be similarly applied to an inner layer material as shown in FIG. 1 (e) in which conductive films on both surfaces are formed after laminating and thermocompression bonding and a conductive pattern is formed on both surfaces.

  With this configuration, the thickness of the conductor can be reduced, so that the wiring density of the inner layer conductor circuit can be improved, and the strength of the surface layer and the inner layer or between the surface layers and the surface layer conductor near the conduction hole can be improved. In addition, it is possible to provide a high-layer printed wiring board capable of improving the electrical connection reliability between layers.

  Moreover, since the insulating layer is a base material obtained by impregnating a resin in a woven or non-woven fabric of an aromatic polyamide, it is suitable for drilling with a laser, so that a high-density printed wiring board can be realized.

  In addition, by using a ceramic material for the insulating layer, it is possible to cope with punching holes such as unfired green sheets, it is possible to improve productivity, and the adhesion of the conductor lands for mounting is high, It is possible to provide a printed wiring board that requires high heat resistance.

  Furthermore, although the laser via 5 is a non-through hole in the present embodiment, it is processed by a drill or the like to form a through hole, which is filled with metal plating, so that the through hole and the conductor in the vicinity thereof are filled. Strength can be improved and reliability of electrical connection can be improved.

  Moreover, it can replace with the copper foil 4 with a resin used in this Embodiment, and can laminate | stack copper foil on the photosensitive resin layer. In this case, when the non-through hole is formed in the photosensitive resin layer, the cross-sectional shape of the non-through hole can be changed to an inverted trapezoidal shape depending on exposure / development conditions. By adopting this configuration, the strength of the through holes that are not penetrating against thermal expansion in the thickness direction of the laminate is improved, and the heat resistance strength of the conductor lands and the reliability of mounting are improved when mounting components. Can do.

  It is also possible to adopt a configuration in which a circuit is formed of a copper-clad laminate in which an insulating layer and copper foil are laminated on a metal plate whose surface has been subjected to insulation treatment, and build-up is performed thereon. Thereby, the printed wiring board excellent in high-density mounting and heat dissipation can be provided.

  Furthermore, after embedding the processed hole by conductive plating, the conductive plating layer formed on both sides of the copper-clad laminate is polished or etched to a thickness in the range of 10 to 30 μm to make the conductive plating layer thin. By providing additional steps, it is possible to easily realize high density and thinning in the formation of the conductor circuit.

(Embodiment 2)
2A to 2D are cross-sectional views illustrating a method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention. The reference numerals in FIG. 2 are the same as those in FIG.

  A method for manufacturing the multilayer printed wiring board configured as described above will be described below.

  First, as shown in FIG. 2 (a), a copper clad laminate having copper foil laminated on both sides of the insulating substrate 3 is coated with an inner layer conductor using means such as a screen printing method or a photographic method. A pattern 2 is formed to obtain an inner layer material 1 for a multilayer printed wiring board.

  Next, as shown in FIG. 2 (b), the copper foil 4 with resin was laminated on the inner layer material 1 having the inner layer conductor pattern 2 formed on the insulating substrate 3, and the copper foil was removed. Then, non-through holes with a hole diameter of 50 μm are formed by laser processing (processing conditions: pulse width 6 μs × 1 time + pulse width 3 μs × 1 time + pulse width 2 μs × 1 time), and further, through holes are formed by drilling or the like. Then, metal plating is performed to obtain a laser via 5 that electrically connects the inner and outer layers and a through hole 6 that electrically connects the inner and outer layers.

  Next, as shown in FIG. 2C, a mask 11 is applied to a via hole that does not need to be filled with metal plating, and further, metal plating is repeated to fill the laser via 5 with metal plating, thereby obtaining a via 7. Thereafter, the mask 11 is removed, and a conductor pattern 8 for the outer layer and a land 9 on the via 7 are formed on the surface using means such as a screen printing method or a photographic method, and a multilayer as shown in FIG. A printed wiring board 10 is obtained.

  By selectively burying only necessary processing holes in this way, the conductive material consumed is reduced, and the thickness of the conductor for wiring is reduced, making it easier to make the conductor thinner and further reducing the weight of the printed wiring board. Can be achieved.

  Further, in the step of FIG. 2C, the via 7 can be obtained by filling the laser via 5 with metal plating by repeating metal plating different from copper metal plating on the surface. As a result, it is possible to select according to the required characteristics for mounting the conductive material that forms the conduction hole, and the etching solution for forming the conductor circuit by etching is selected according to the circuit formation method can do.

  In particular, by forming only the processing hole and the vicinity of the processing hole by metal plating, the solderability between the component terminal and the conductor land in component mounting and the contact resistance as a contact electrode are minimized, and other wiring conductors are also used. Thinning is easy because it is composed only of copper foil.

(Embodiment 3)
3A to 3D are cross-sectional views showing a method for manufacturing a multilayer printed wiring board according to an embodiment of the present invention. In FIG. 3, 12 is a through-hole which makes the front and back of the inner layer material conductive, and the other symbols are the same as in FIG.

  A method for manufacturing the multilayer printed wiring board configured as described above will be described below.

  First, as shown in FIG. 3 (a), a hole for forming a through hole is formed on a copper-clad laminate obtained by laminating copper foil on both sides of an insulating substrate 3 using an NC drilling machine, and both sides are formed by copper plating. A through hole 12 to be electrically connected is formed. Further, the inner layer conductor pattern 2 is formed by using the copper foil of the copper-clad laminate using a screen printing method or a photographic method to obtain the inner layer material 1 for the multilayer printed wiring board.

  Next, as shown in FIG.3 (b), the copper foil 4 with a resin was laminated to the inner layer material 1 which has the conductor pattern 2 for inner layers formed on the insulating substrate 3, and the copper foil was removed. Then, non-through holes with a hole diameter of 50 μm are formed by laser processing (processing conditions: pulse width 6 μs × 1 time + pulse width 3 μs × 1 time + pulse width 2 μs × 1 time), and further, through holes are formed by drilling or the like. Then, metal plating is performed to obtain a laser via 5 that electrically connects the inner and outer layers and a through hole 6 that electrically connects the inner and outer layers.

  Next, as shown in FIG. 3C, the via 7 is obtained by further filling the laser via 5 with metal plating by repeating metal plating. Thereafter, the outer layer conductor pattern 8 and the land 9 on the via 7 are formed on the surface by using a screen printing method, a photographic method or the like to obtain a multilayer printed wiring board 10 as shown in FIG. ing.

  In the above description, the example has been described in which the through hole that makes the front and back of the inner layer material conductive is embedded with a resin-coated copper foil resin. However, the thermosetting resin and the conductive paste are provided in the other conductive holes. It is also possible to embed in advance. With this configuration, voids in heating lamination and variations in plate thickness can be reduced.

  In the above explanation, the example in which the via is filled with the metal plating by repeating the same metal plating as the surface metal plating has been described, but by repeating the metal plating different from the surface metal plating, A configuration in which a mask is formed on a via that does not need to be filled by metal plating, a via is buried by repeating metal plating, and then the mask is removed can be similarly implemented.

  When the multilayer printed wiring board according to the present embodiment is compared with the case of IVH by conventional build-up, a land can be formed on the via, so that the wiring capacity and the mounting density can be greatly improved.

  As described above, according to the present embodiment, it is possible to provide a multilayer printed wiring board capable of dramatically improving the mounting density.

  As described above, the present invention makes it possible to mount a component or the like on a through hole or a non-through hole, and has a peeling strength that can withstand dimensional changes even after component soldering in a high temperature atmosphere. A printed wiring board suitable for high-density mounting having lands can be provided by an easy method.

(A)-(e) is process sectional drawing which shows the manufacturing method of the multilayer printed wiring board of Embodiment 1 of this invention. (A)-(d) is process sectional drawing which shows the manufacturing method of the multilayer printed wiring board of Embodiment 2 of this invention. (A)-(d) is process sectional drawing which shows the manufacturing method of the multilayer printed wiring board of Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner layer material 2 Inner layer conductor pattern 3 Inner layer insulating substrate 4 Resin copper foil 5 Laser via 6 Through hole 7 Via filled with metal plating 8 Outer layer conductor pattern 9 Land on via 10 Multilayer printed wiring board 11 Mask 12 Through hole for electrical connection between inner layers

Claims (33)

A printed wiring board in which a processing hole is formed in a copper clad laminate made of copper foil and an insulating layer, and the processing hole is embedded by conductive plating. The printed wiring board according to claim 1, wherein the processed hole is a through hole. The printed wiring board according to claim 1, wherein the processed hole is a non-through hole. The printed wiring board according to claim 1, wherein a conductor land for mounting is formed on the processed hole. The printed wiring board according to claim 1, wherein the copper-clad laminate is a multilayer copper-clad laminate having a circuit forming substrate as an inner layer. The printed wiring board according to claim 1, wherein non-through holes for interlayer connection are formed in the multilayer copper-clad laminate according to claim 5. The printed wiring board according to claim 5, wherein the circuit forming substrate is a multilayer circuit forming substrate. The printed wiring board according to claim 7, wherein the interlayer connection of the multilayer circuit forming substrate is formed by a conduction hole filled with a conductive paste. The printed wiring board according to claim 5, wherein the cross-sectional shape of the non-through hole is an inverted trapezoidal shape. The printed wiring board according to claim 1, wherein the diameter of the processed hole is in a range of 20 to 100 μm. The printed wiring board according to claim 5, wherein the non-through hole has a depth of 40 to 200 μm. The printed wiring board according to claim 1, wherein the conductive plating is formed of a conductive material different from copper foil. The printed wiring board according to claim 1, wherein only the processed hole and the vicinity of the processed hole are formed by gold plating. 2. The printed wiring board according to claim 1, wherein the insulating layer is a base material obtained by impregnating a woven or non-woven fabric of aromatic polyamide with a resin. The printed wiring board according to claim 1, wherein the insulating layer is a ceramic material. The printed wiring board according to claim 5, wherein a thermosetting resin is filled in advance in the conduction hole of the inner-layer circuit forming substrate having a conduction hole penetrating therethrough. The printed wiring board according to claim 1, wherein the printed wiring board is a copper-clad laminate comprising a copper plate, a metal plate having a surface subjected to insulation treatment, and an insulating layer. The printed wiring board according to claim 1, wherein processing holes are selectively embedded. A method for producing a printed wiring board, comprising: forming a processed hole in a copper clad laminate comprising a copper foil and an insulating resin layer; and embedding the processed hole by conductive plating. The method for producing a printed wiring board according to claim 19, wherein a through hole is provided. The method for manufacturing a printed wiring board according to claim 19, wherein a non-through hole is provided. The method for manufacturing a printed wiring board according to claim 19, wherein the machining hole is formed by a laser. The method for producing a printed wiring board according to claim 22, wherein a carbon dioxide laser having a focal beam diameter of 40 to 120 μm is used. The method for manufacturing a printed wiring board according to claim 19, wherein the processed hole is treated with an alcohol-based solution after forming the processed hole. The method for manufacturing a printed wiring board according to claim 19, wherein the copper foil is a copper foil with an adhesive resin. The method for manufacturing a printed wiring board according to claim 19, wherein the copper foil and the insulating resin layer having adhesiveness are laminated and heat-pressed to form a copper-clad laminate. The method for producing a printed wiring board according to claim 19, wherein the copper foil with adhesive resin and the circuit forming substrate are laminated and heat-pressed to form a multilayer copper-clad laminate. A step of forming a through-hole in an insulating resin base material having adhesiveness, a step of filling the through-hole with a conductive paste, a step of laminating copper foil on both sides and thermocompression bonding, and a copper foil on both sides 28. The method of manufacturing a printed wiring board according to claim 27, wherein the circuit forming substrate is formed by selectively etching to form a conductor circuit. The method for producing a printed wiring board according to claim 28, wherein an aromatic polyamide nonwoven fabric epoxy resin substrate is used as the insulating resin substrate. The method for manufacturing a printed wiring board according to claim 19, wherein the conductive plating layer formed on both sides of the copper-clad laminate is polished or etched after embedding the processed hole by conductive plating. The manufacturing method of the printed wiring board of Claim 30 which grind | polishes or etches a conductive plating layer to the thickness of the range of 10-30 micrometers. The print according to claim 19, wherein after forming the processed hole, the processed hole (and the copper foil surface) is selectively covered with a peelable plating resist, and the plating resist is peeled and removed after conductive plating. A method for manufacturing a wiring board. The method for producing a printed wiring board according to claim 32, wherein the conductive plating is performed with a metal different from copper foil.

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