JP3694708B2 - Printed wiring board manufacturing method and printed wiring board - Google Patents

Description

  The present invention relates to a method of manufacturing a printed wiring board, and more particularly, a highly reliable printed wiring having a conductor wiring portion for connecting between wiring pattern layers and a through hole for inserting a component pin and capable of high-density wiring and mounting. The present invention relates to a method capable of producing a plate with good yield while reducing the number of steps.

  In order to increase the functionality of a wiring circuit or to make it more compact, wiring patterns are being made multilayer. In this type of multilayer printed wiring board, electrical connection between the inner wiring pattern layers and between the inner wiring pattern layer and the surface wiring pattern layer is inevitably required. It is done. For example, after patterning the copper foil stretched on both sides of the substrate, if necessary, an electrical connection part between both sides called IVH is formed, and then an insulating sheet (for example, prepreg) is formed on the patterning surface. Then, copper foil is laminated and arranged, and integrated by heating and pressing. The electrical connection between both surfaces, called IVH, is performed by drilling a predetermined position on the substrate and depositing a conductive layer on the inner wall surface of the hole by plating. After integration by pressing, as in the case of the double-sided type described above, through-hole processing and plating treatment, electrical through-hole connection between wiring pattern layers and solderable through-holes for component pin insertion are made. By forming and patterning the surface copper foil, a multilayer printed wiring board having a required wiring pattern interlayer connection portion and a through hole for inserting a component pin is obtained. In the case of a multilayer printed wiring board having more wiring pattern layers, it can be manufactured by a method of increasing the number of double-sided mold boards interposed in the middle.

  In the printed wiring board manufacturing method, as a method for performing electrical connection between wiring pattern layers without using a plating method, a hole is formed at a predetermined position of a double-sided copper foil-clad substrate, and a conductive paste is printed in the hole. For example, a method of electrically connecting the wiring layers by curing the resin content of the conductive paste poured into the hole by pouring is used.

  As described above, in the method of manufacturing a printed wiring board using a plating method for electrical connection between wiring pattern layers, drilling (perforating) processing for electrical connection between wiring pattern layers on a substrate, There are disadvantages that a plating process including the inner wall surface of the bored hole is required, the manufacturing process of the printed wiring board is redundant, and the process management is complicated. On the other hand, the method of embedding a conductive paste in the holes for electrical connection between the wiring pattern layers by printing or the like requires a drilling step as in the case of the plating method. In addition, it is difficult to uniformly (uniformly) pour and embed the conductive paste into the drilled holes, and there is a problem in reliability of electrical connection. In any case, considering the tendency to increase the number of connection portions between wiring pattern layers with higher functionality, the need for the drilling step (increases the number of drilled portions) There is a drawback that it cannot reflect the demand for cost reduction, etc., reflecting the yield.

Also, if the electrical connection structure of the wiring pattern layers, the front and back surfaces of the printed wiring board, since the conductor hole for the wiring pattern layers connection is established, the wiring area of the conductor hole It cannot be formed or placed. Further, since electronic components cannot be mounted, there are problems that improvement in wiring density is restricted and improvement in mounting density of electronic components is hindered. In other words, the printed wiring board obtained by the conventional manufacturing method cannot sufficiently meet the demands such as downsizing of the circuit device by high-density wiring and high-density mounting, and consequently downsizing of the electronic equipment, and the cost A practical and more effective method for producing a printed wiring board including a surface is desired.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of producing a highly reliable printed wiring board with a high yield, capable of high-density wiring and mounting by a simple process. .

In the first printed wiring board manufacturing method according to the present invention, the first conductive metal layer in which conductor bump groups are formed at predetermined positions is contacted to the first main surface of the first synthetic resin sheet. And laminating, heating, and pressurizing, and the conductive bump group penetrates the first synthetic resin sheet to form a combined body protruding from the second main surface of the synthetic resin sheet ; A second conductive metal layer is laminated in contact with the conductor bump group projecting surface of the combined body, heated and pressurized, and the conductor bump group is brought into contact with the second conductive metal layer and is plastic. Deforming and forming a first double-sided printed wiring board in which the first and second conductive metal layers are connected by the conductive bump group via the first synthetic resin-based sheet; Patterning the first and second conductive metal layers of one double-sided printed wiring board, and And a second double-sided printed wiring element having at least one surface patterned on both sides of the first double-sided printed wiring board on which the second conductive metal layer is patterned via a second synthetic resin sheet. Laminating the patterned surfaces of the boards facing each other and integrating them by heating and pressing to form a multilayer printed wiring board; and forming through holes in the multilayer printed wiring board to form first and first And a step of connecting the conductive metal layers of the double-sided printed wiring board .
In the second printed wiring board manufacturing method according to the present invention, the first conductive metal layer in which conductor bump groups are formed at predetermined positions on the first main surface of the first synthetic resin-based sheet is contacted. And laminating, heating and pressurizing, and forming a plurality of combined bodies in which the conductive bump group penetrates the first synthetic resin sheet and protrudes from the second main surface of the synthetic resin sheet . The both sides of the double-sided printed wiring board on which both sides are patterned are laminated so that the protruding surface of the conductor bump group of the combined body is brought into contact with each other, and heated and pressed to form the double-sided printed wiring. A multilayer printed wiring board is formed by contacting and plastically deforming the conductive metal layer of the base plate to connect the conductive metal layer of the combined body and the conductive metal layer of the double-sided printed wiring base plate. A step of forming a through hole in a predetermined position of the multilayer printed wiring board Comprising conductive metal layer and the step of connecting the conductive metal layer of the double-sided printed wiring material plate, characterized by comprising.

  In the present invention, the conductive metal layer forming the conductor bump group includes, for example, a conductive sheet (foil) such as electrolytic copper foil, and the conductive metal layer may be a single sheet, It may be patterned, its shape is not particularly limited, and the conductor bump group may be formed in a shape formed on both main surfaces as well as on one main surface.

Here, the conductor bump, for example, silver, gold, copper, conductive powder such as solder powder, and these alloy powders or composite (mixed) metal powder, for example a polycarbonate resin, a polysulfone resin, a polyester resin, a phenoxy resin, an E Nord resin, the conductive composition was prepared and a binder component are mixed, such as polyimide resin, or formed like a conductive metal. When forming the bump group with a conductive composition, a bump having a high aspect ratio can be formed by, for example, a printing method using a relatively thick metal mask. Furthermore, the height of the bump group may be suitably mixed with a height that can penetrate one layer of the synthetic resin-based sheet and a height that can penetrate a plurality of layers of the synthetic resin-based sheet. . In the formation of the conductor bumps, if the through-holes (through holes) are to be formed so that a part of the conductor bumps are exposed at a plurality of locations on the inner wall surface of the through-hole to be plated, This makes it easier to form a metal layer. On the other hand, as means for forming a bump group with a conductive metal, (a) a fine metal lump having a certain shape or size is dispersed on the surface of the conductive metal layer on which an adhesive layer has been provided in advance. either to fix (at this time may Tsu line by placing a mask), and print-patterned plating resist (b) electrolytic copper foil surface, selective copper, tin, gold, silver, solder plating to (C) Applying and patterning a solder resist on the surface of the conductive metal layer and then immersing it in a solder bath to selectively form minute metal columns (bumps). Can be mentioned. Here, small metal columns to no small slug corresponding to the bumps, a multilayer structure formed by combining different metal, or a multilayer shell structure. For example, copper may be cored and the surface may be coated with a gold or silver layer to provide oxidation resistance, or copper may be cored and the surface may be coated with a solder layer to provide solder jointability. In the present invention, when the bump group is formed of a conductive composition, the process can be further simplified as compared with the case of using a plating method or the like, which is effective in terms of cost reduction.

In the present invention, examples of the synthetic resin sheet in which the conductor bump group is inserted to form a penetrating conductor wiring portion include a thermoplastic resin film (sheet), and the thickness thereof is about 50 to 800 μm. Is preferred. Here, examples of the thermoplastic resin sheet include sheets such as polycarbonate resin, polysulfone resin, thermoplastic polyimide resin, tetrafluoropolyethylene resin, hexafluoropolypropylene resin, and polyetheretherketone resin. In addition, the thermosetting resin sheet held in the pre-curing state includes epoxy resin, bismaleimide triazine resin, polyimide resin, phenol resin, polyester resin, melamine resin, or butadiene rubber, butyl rubber, natural rubber, neoprene rubber, silicone. Examples thereof include raw rubber sheets such as rubber. These synthetic resins may be used alone or may contain insulating inorganic or organic fillers, and sheets made of glass cloth or mat, organic synthetic fiber cloth or mat, or a sheet combined with a reinforcing material such as paper. There may be.

  Furthermore, in the present invention, a laminated body in which a plurality of layers having a configuration in which the main surface of the synthetic resin sheet is brought into contact with the main surface of the conductive metal layer in which the bump group is formed is heated and pressurized. In some cases, the base (plate) on which the synthetic resin-based sheet is placed is a metal plate or heat-resistant resin plate with little size and deformation, such as a stainless steel plate, a brass plate, a polyimide resin plate (sheet), polytetrafluoroethylene. A resin plate (sheet) or the like is used.

The through-hole drilling may be a conventional means in the production of printed wiring boards such as drills, and the plating process on the inner wall surface of the drilled through-hole is chemical plating (electroless plating) or chemical plating. And electroplating. Since the drilling process and the plating process are much smaller than the number of electrical connection portions between the wiring pattern layers, such as the so-called through-hole connection in the prior art, the process complexity is hardly a problem.

  According to the method for manufacturing a printed wiring board according to the present invention, the conductor wiring portion between the layers that electrically connect the wiring pattern layers is composed of an interlayer insulating layer by heating and pressing in a so-called stacking and integrating process. A highly reliable electrical connection between the wiring pattern layers is reliably achieved by plasticizing the resin-based sheet or a state similar thereto and press-fitting the conductor bump group on the surface of the conductive metal layer. That is, it is possible to form a highly accurate and highly reliable electrical connection at an arbitrary position (location) between fine wiring pattern layers while simplifying the process. In other words, a printed wiring board having a high wiring density can be manufactured at a low cost, and it is not necessary to form a connection hole for electrical connection between the wiring pattern layers. It is possible to obtain a printed wiring board capable of high-density mounting and capable of reliably and reliably mounting pin insertion type components.

  According to the present invention, the process of forming conductive bumps connecting the pattern layers, the process of arranging and heat-synthesizing the synthetic resin sheets, the process of patterning the outer layer, in other words, the simplification of the process, that is, the manufacturing process It is possible to easily manufacture a double-sided printed wiring board or a multilayer type printed wiring board while reducing the number of processes to a significantly smaller number of steps than the conventional manufacturing method. In particular, in the production of a multilayer printed wiring board with many repeated processes, the number of processes is greatly reduced, which is effective in improving productivity or mass productivity. In addition, since the drilling process and plating process that are indispensable in the manufacturing process of the conventional multilayer printed wiring board and the like are not required, defects generated in the manufacturing process are greatly suppressed, and the yield is improved. In addition, a highly reliable printed wiring board can be obtained. In addition, since the printed wiring board to be manufactured does not have holes for interlayer connection on the surface, the wiring density can be remarkably improved, and the mounting area for electronic components can be set regardless of the position of the holes. As a result, the mounting density is also greatly improved and the distance between the mounted electronic components can be shortened, so that the circuit performance can be improved. That is, it can be said that the present invention not only contributes to the cost reduction of the printed wiring board but also greatly contributes to the compactness and high performance of the mounted circuit device.

  Hereinafter, FIGS. 1A to 1C, FIGS. 2A and 2B, FIGS. 3A and 3B, FIGS. 4A to 4D, and FIGS. 5A to 5C. Embodiments of the present invention will be described with reference to the respective drawings.

[Example 1]
FIGS. 1A to 1C, FIGS. 2A and 2B, and FIGS. 3A and 3B schematically show embodiments of the present embodiment. First, an electrolytic copper foil having a thickness of 35 μm is used as the conductive metal layer 1, a polymer type silver-based conductive paste (trade name, thermosetting conductive paste MS-7, Toshiba Chemical KK), A metal mask in which a hole having a diameter of 0.35 mm was formed at a predetermined position of a 300 μm stainless steel plate was prepared. Then, the the electrolytic copper foil 1 side, the printed conductive paste is positioned and arranged a metal mask, after the printed conductive paste is dried, 3 in a way that re-printed in the same position with the same mask Repeated printing was repeated to form (form) a mountain-shaped conductor bump 2 having a height of 20 to 300 μm.

On the other hand, a glass epoxy prepreg (synthetic resin sheet) 3 having a thickness of 160 μm and an electrolytic copper foil 1 ′ having a thickness of 35 μm are prepared, and a conductor bump 2 forming surface side of the electrolytic copper foil 1 in which the conductor bump 2 is formed. Next, the synthetic resin sheet 3, aluminum foil and rubber sheet are laminated and arranged, and hot pressing is performed to create a sheet in which the tip of the conductor bump 2 penetrates the synthetic resin sheet 3, and is taken out after cooling. The aluminum foil and the rubber sheet are peeled off, and the electrolytic copper foil 1 ′ is laminated and arranged on the surface of the synthetic resin sheet 3 with the end of the conductor bump 2 inserted, and then, for example, between the hot press hot plates kept at 170 ° C. When it is placed and the synthetic resin sheet 3 is in a thermoplastic state, it can also be produced by pressing the resin pressure at 1 MPa for about 1 hour.

  A normal etching resist ink (trade name, PSR-4000H, solar ink KK) is screen-printed on the electrolytic copper foils 1, 1 'on both sides of the surface copper-clad laminate, masking the conductor pattern portion, After the etching process using 2 copper as an etchant, the resist mask was peeled off to obtain a double-sided printed wiring board 4 shown in cross section in FIG.

Next, on both sides of the double-sided printed wiring board, a copper-clad laminate (2 sheets) 5 and a glass epoxy prepreg (synthetic resin sheet) 3 having a wiring pattern on one side are prepared, and FIG. As shown in cross section in a), each was positioned and arranged to form a laminate. Thereafter, obtained was placed between the hot plate of hot press maintained at 170 ° C., a state where the synthetic resin sheet 3 is thermally plasticized at 1MPa as resin pressure pressurized extraction as it cooled, the multilayer laminate It was. A through hole 6 is drilled at a predetermined position of the multilayer laminate, and chemical copper plating is selectively applied to the inner wall surface of the through hole 6 for about 3 hours. the copper layer 7 of 7 microns m was deposited and formed. Thereafter, an ordinary etching resist ink (trade name, PSR-4000H, solar ink KK) is screen-printed on the electrolytic copper foil 1 ′ on both sides of the multilayer laminate, and the conductor pattern portion is masked, and then the second chloride. After etching using copper as an etching solution, the resist mask was peeled off to obtain a multilayer printed wiring board 8.

Wherein the multi-layered printed wiring board 8 prepared was subjected to electrical check is usually carried out, problems such as all bad stone reliability connection was observed. In order to evaluate the reliability of connection between wiring patterns, a hot oil test was conducted 500 times (a cycle of 10 seconds immersion in 260 ° C. oil and 20 seconds immersion in 20 ° C. oil). However, no defects were observed, and there was no problem in connection reliability between the conductive (wiring) pattern layers even when compared with the conventional copper plating method.

[Example 2]
In this embodiment, in the case of the above-described embodiment 1, the conductive bump 2 forms the conductive connection portion 2a on each of the two wiring pattern layers on both sides (outside), and both the electrolytic copper foil 1 and the wiring pattern are provided. Using a double-sided wiring base plate 5 having a connected configuration and a double-sided wiring base plate 4 'having no through-hole connection as an inner layer, as shown in cross section in FIG. When the synthetic resin-based sheet 3 is in a thermoplastic state, it is placed at a pressure of 1 MPa as the resin pressure, and is taken out after cooling to obtain a multilayer laminate. A through hole 6 is drilled at a predetermined position of the multilayer laminate, and chemical copper plating is selectively applied to the inner wall surface of the through hole 6 for about 3 hours. A 7 μm copper layer 7 was deposited. Thereafter, an ordinary etching resist ink (trade name, PSR-4000H, solar ink KK) is screen-printed on the electrolytic copper foil 1 ′ on both sides of the multilayer laminate, and the conductor pattern portion is masked. After etching using copper as an etching solution, the resist mask was peeled off to obtain a multilayer printed wiring board 8.

  When the manufactured multilayer printed wiring board 8 was subjected to a normal electrical check, no problems such as defects or reliability were found in all connections. In order to evaluate the reliability of connection between wiring patterns, a hot oil test was performed 500 times (a cycle of 20 seconds immersion in oil of 20 ° C. and 20 seconds immersion in oil of 260 ° C. as one cycle). No defects were observed, and there was no problem in connection reliability between the conductive (wiring) pattern layers even when compared with the conventional copper plating method.

[Example 3]
As in the case of Example 1, a 35 μm-thick electrolytic copper foil, which is usually used in the manufacture of printed wiring boards, is used as a conductive metal layer, and a polymer-type silver conductive paste (trade name, heat A curable conductive paste MS-7, Toshiba Chemical KK) was used as a conductive paste, and metal masks each having a 0.35 mm diameter hole in a predetermined position of a 300 μm thick stainless steel plate were prepared. Then, the metal mask is positioned and arranged on the electrolytic copper foil, and a conductive paste is printed. After the printed conductive paste is dried, the same mask is used and printed again at the same position twice. A mountain-shaped conductor bump having a height of 200 to 300 μm was formed (formed).

Next, as shown in cross section in FIG. 4 (a), the predetermined position on the conductor bumps group 2 formed by printing and electrolytic copper foil 1 on the thickness of about 160μm of synthetic resin sheet 3, aluminum foil, rubber the sheets were stacked (not shown), positioned and arranged to heat plates holding the heat up less in 100 ° C., a glass transition point or higher, is preferably a resin component of the synthetic resin sheet 3 becomes plastic state When the aluminum foil and the rubber sheet were peeled off after being pressurized at a high temperature, the aluminum foil and the rubber sheet were peeled off. Next, the electrolytic copper foil 1 ′ is laminated on the side where the tip of the conductor bump 2 of the laminate of the electrolytic copper foil 1 and the synthetic resin sheet 3 is inserted and exposed, and pressurized at 170 ° C. for 1 hour and 1 MPa. As a result, both ends of the conductor bump 2 are joined to the electrolytic copper foil 1 ′, the synthetic resin sheet 3 is cured, and the conductive wiring portion 2 a is connected between the double-sided electrolytic copper foils 1, 1 ′ in a penetrating manner. A copper-clad plate was obtained (FIG. 4B).

A normal etching resist is attached to both sides of this double-sided copper-clad plate with a laminator, the negative film is aligned, exposed and developed, and then the copper foils 1 and 1 'are etched . Finally, the etching resist is stripped with an alkaline aqueous solution. Then, a conductor pattern was formed, and a double-sided wiring base plate 4 was created (see FIG. 4C). About the said double-sided wiring base plate 4, when each conductor wiring part 2a was continually tested from the front and back with a tester, the total number was 2 mΩ or less.

In a predetermined position formed according to the above, an electrolytic copper foil 1 printed with a group of conductor bumps 2, a synthetic resin sheet 3 having a thickness of about 160 μm, an aluminum foil and a rubber sheet are laminated (not shown), 100 After holding at 7 ° C. for 7 minutes, pressurization was performed at 1 MPa for 3 minutes, and then the aluminum foil and the rubber sheet were peeled off to obtain a member formed by inserting the synthetic resin sheet 3 with which the tip of the conductor bump 2 contacts. This member and the double-sided wiring base plate 4 are positioned, stacked, and arranged as shown in a cross-sectional view in FIG. 4C, and held at 170 ° C. for 30 minutes under a pressure of 1 MPa. joined to the wiring pattern surface of the double-sided wiring element board 4, as shown in cross section in FIG. 4 (d), to create a double-sided copper clad laminate.

  In the configuration of the double-sided copper-clad plate, for example, when a through hole 6 for pin insertion is formed around a position where a discrete component pin is to be inserted / mounted, one of the conductor bumps 2 is formed on the inner wall surface of the through hole 6. Four through-type conductor wiring portions 2b are formed so that the portions are exposed. That is, in the region where the through hole 6 for inserting the component pin is formed, as shown in FIG. 5B, the four through-type conductor wiring portions 2b (see FIG. 4D) are particularly formed. It is set up.

Next, a through hole 6 for inserting a discrete component pin is formed by drilling at substantially the center of the through-type conductor wiring portion 2b of the double-sided copper-clad plate, and then the inner wall surface of the through hole 6 is subjected to chemical copper plating. Was applied for 3 hours to deposit a copper layer 7 having a thickness of about 7 μm. Then, the both surfaces copper 1,1 surface of double-sided copper-clad plate, affixed to conventional etching resist laminator, aligning the negative film, the same as in the case of the, and etching treatment, 5 As shown in a sectional view in FIG. 5C and in a plan view in FIG. 5D, a component mounting through-hole 6 made of a high-quality copper layer 7 connected to the through-type conductor wiring portion 2b and a pad are provided. A four-layer thin multilayer wiring board 8 having a thickness of about 550 μm was prepared.

When a discrete circuit pin was inserted into the through-hole 6 of the four-layer thin multilayer wiring board 8 and soldered to form a mounting circuit device, a highly reliable connection mounting of the discrete circuit was achieved.

[Example 4]
In Example 3, a four-layer thin multilayer wiring board 8 was prepared under the same conditions except that a copper paste was used instead of forming the conductor bumps 2 with a silver paste. In the case of this embodiment, when a through hole 6 for a discrete component pin is drilled at the center of the four through-type conductor wiring portions 2b, a conductor containing copper is exposed on the inner wall surface of the through hole. I was able to insert the discrete component pins and solder them.

  In the multilayer wiring board, when discrete components are mounted, chemical copper plating on the inner wall surface of the through hole (through hole) is indispensable. However, when the configuration of Example 4 is adopted, soldering is performed. There is no need for chemical copper plating, and the reliability of electrical connection between the surface wiring pattern layer and the inner wiring pattern is ensured by a plurality of through-type conductor wiring portions 2b. Can be established.

FIG. 1 schematically shows the basics of the first embodiment of the present invention, in which (a) shows a state in which a conductive metal layer having a conductive bump formed thereon, a synthetic resin-based sheet, and a conductive metal layer are positioned and laminated. (B) is a cross-sectional view of a state in which the laminate is press-integrated by hot pressing, and (c) is a cross-sectional view of a double-sided wiring element board obtained by patterning both conductive metal layers. BRIEF DESCRIPTION OF THE DRAWINGS It shows typically the 1st embodiment example of this invention, (a) is sectional drawing of the lamination | stacking and arrangement | positioning state of the synthetic resin type sheet | seat on both sides of a double-sided type | mold wiring base plate, and the copper-clad laminated base plate patterned on one side (B) is sectional drawing which shows the structural state of the multilayer wiring board finally formed. FIG. 2 schematically shows a second embodiment of the present invention, wherein (a) shows a board with a through-conductive connection portion that is patterned on one side on both sides of a double-sided wiring board that does not have a through-conductive connection portion. Sectional drawing of the lamination | stacking and arrangement | positioning state of a copper clad laminated base plate, (b) is sectional drawing which shows the structural state of the multilayer wiring board finally formed. The 2nd example of an embodiment of the present invention is shown typically, and (a) is a section of a state where a conductive metal layer, a synthetic resin system sheet, and a conductive metal layer which are provided with conductive bumps are positioned and laminated. (B) is a cross-sectional view of a double-sided wiring element board obtained by patterning both conductive metal layers after pressure-integrating the laminate by hot pressing, and (c) is a double-sided wiring element board, conductive Sectional drawing of the state which positioned and laminated | stacked what the conductor bump formed in the conductive metal layer penetrated the synthetic resin type | system | group sheet, (d) is the double-sided copper clad laminated board which pressurized and integrated the laminated body with the hot press FIG. The 2nd example of an embodiment of the present invention is shown more typically, (a) is a double-sided copper-clad laminate (a sectional view in which both sides of FIG. 4 (d) are patterned, (b) shows the both sides. A plan view of the patterned state, (c) is a sectional view of a state in which a component pin insertion hole is drilled and a copper plating layer is formed on the inner wall, and (d) is a state in which the copper plating layer is formed on the inner wall surface FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1 '... Conductive metal layer, 2 ... Conductor bump, 2a ... Conductor connection part, 2b ... Penetration type conductor connection part, 3 ... Synthetic resin type | system | group sheet, 4 ... Double-sided type | mold wiring board, 4' ... Conductor connection part No double-sided wiring board, 5 ... One-side patterned copper-clad laminated board, 6 ... Through hole, 7 ... Copper plating layer, 8 ... Multilayer printed wiring board, 9 ... Pad

Claims (2)

On the first main surface of the first synthetic resin-based sheet, a first conductive metal layer having conductor bump groups formed in predetermined positions is laminated so as to be in contact with each other, and heated and pressed to form the conductor bump groups. Forming a combined body projecting from the second main surface of the synthetic resin sheet through the first synthetic resin sheet ,
A second conductive metal layer is laminated in contact with the conductor bump group projecting surface of the combined body, heated and pressurized, and the conductor bump group is brought into contact with the second conductive metal layer and is plastic. Deforming and forming a first double-sided printed wiring base plate in which the first and second conductive metal layers are connected by the conductor bump group via the first synthetic resin-based sheet;
Patterning the first and second conductive metal layers of the first double-sided printed wiring board;
A second double-sided type in which at least one side is patterned on both sides of the first double-sided printed wiring board on which the first and second conductive metal layers are patterned via a second synthetic resin sheet. Laminating the patterned surfaces of the printed wiring board facing each other and integrating them by heating and pressing to form a multilayer printed wiring board; and
Forming a through-hole in the multilayer printed wiring board and connecting the conductive metal layers of the first and second double-sided printed wiring boards to each other. Production method. On the first main surface of the first synthetic resin-based sheet, a first conductive metal layer having conductor bump groups formed in predetermined positions is laminated so as to be in contact with each other, and heated and pressed to form the conductor bump groups. Forming a plurality of combined bodies protruding from the second main surface of the synthetic resin sheet through the first synthetic resin sheet ,
On both sides of a double-sided printed wiring board that is patterned on both sides, the conductor bump group projecting surfaces of the combined body are laminated in contact with each other, and heated and pressed to form the conductive bump group on the double-sided printed wiring board. A process of forming a multilayer printed wiring board by contacting and plastically deforming the conductive metal layer of the board to connect the conductive metal layer of the combined body and the conductive metal layer of the double-sided printed wiring board. When,
Forming a through hole at a predetermined position of the multilayer printed wiring board and connecting the conductive metal layer of the combined body and the conductive metal layer of the double-sided printed wiring board. A method of manufacturing a printed wiring board characterized by the above.

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