KR20050099601A - Substrate having a wiring layer and method of manufacturing the same - Google Patents

Abstract

After the wiring layers 12a to 12d are formed on both sides of the insulating substrate 11, the through holes 14a and 14b penetrating the double wiring layers 12a and 12c and 12b and 12d are formed by punching presses. A method of manufacturing a wiring board is disclosed in which through-holes 14a and 14b are filled with conductors 16a and 16b by punching presses to electrically connect the two wiring layers. In this method, through-hole formation and conductor filling into the through-holes can be performed by punching presses, eliminating the need for smearing and ensuring electrical connection. In addition, an insulating sheet 21 having a wiring pattern 23 formed on both surfaces or one side thereof, and a conductor 28 filled in the wiring pattern 23 and the through hole 26 passing through the insulating sheet 21 are formed. At least one end surface of the conductor 28 protrudes from the mating surface with the insulating sheet 21 and / or the wiring pattern 23 to start a printed circuit board. Several printed circuit boards are laminated | stacked through the insulating adhesive layer, and collectively lamination | stacking is attained only by crimping | bonding them.

Description

Substrate having a wiring layer and a manufacturing method thereof {SUBSTRATE HAVING A WIRING LAYER AND METHOD OF MANUFACTURING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate having a wiring layer such as a printed circuit board or a flexible tape, and a method for manufacturing the same, and more particularly, to a single layer or multilayer printed wiring board that can be manufactured using a punching press and a method for manufacturing the same.

Various things are used as a circuit board which has a conductor layer in front and back. Specifically, in addition to fixed tape such as TAB (Tape Automated Bonding) tape, CSP (Chip Size Package), BGA (Ball Grid Array), FPC (Flexible Printed Circuit) using flexible polyimide resin, etc. And multilayer wiring boards using substrates.

As a manufacturing method of the board | substrate which has a conductor layer in such front and back, there is the following method. Holes, such as through holes or blind via holes, are made in advance in the desired location of the substrate by punching press, drill, or laser light. In addition, when using a laser beam, it is necessary to remove what is called smear (desmear) generate | occur | produced by the heat of a laser beam.

Then, in the method of filling this hole with a conductive paste or the like using a screen printing machine to electrically connect the conductor layers on the front and back surfaces, in the case of through holes (through holes), in order to avoid the paste from entering the back surface side, After a process, it is necessary to adhere | attach a back adhesive sheet, etc., and after that, it is necessary to go through a long process of printing and hardening | curing a conductive paste and peeling a back adhesive sheet. In addition, in the case of blind bead holes, since the aperture diameter of the mask must be strictly set in order to fill the paste into the holes, an accurate positional accuracy such as an image recognition device is required for the printing press, and the printing press becomes expensive. Furthermore, there are drawbacks that lead to higher product costs.

In the case of the plating method, electrolytic copper plating is carried out after electroless copper plating or carbon is attached to the holes, but there is a problem of waste liquid treatment because it is a wet method.

Apart from the reliability of the electrical connection, there is a demand for the development of new methods that are cost-effectively improved over these methods. For example, Japanese Patent Application Laid-Open No. 59-61992 and Japanese Patent Laid-Open No. 62-81789 propose a method of solving such a problem.

In Japanese Patent Laid-Open No. 59-61992, a wiring pattern (wiring layer) having a conductive part made of copper foil covering the through hole is formed on both sides of an insulating substrate, and a hole smaller than the diameter of the through hole is drilled again in the center of the conductive part. The manufacturing method of the through-hole printed wiring board which makes a conductive member contact with both surfaces, and then fixes an electrically conductive part with a conductive member, and conducts copper foil of both surfaces is disclosed.

However, this method has a problem in that a process of forming a through hole, punching a small hole, fixing by a conductive member, and the like becomes complicated. In addition, a part of the conductive portion may be melted to come into contact with the conductive portion on the other surface side, and the smoothness of the surface may deteriorate, resulting in a decrease in reliability of the electrical connection.

In Japanese Patent Application Laid-Open No. 62-81789, a through hole is formed in a unbaked ceramic (green sheet) by a punching press, a through pin is inserted into the through hole, and then the screen is printed on the surface of the substrate. A method of producing a wiring board by printing a layer and firing the green sheet again is described.

This method uses a green sheet as a substrate and does not use an insulating substrate such as polyimide.

In Fig. 1, a circuit board having such a conventional wiring pattern, for example, a 2 metal TAB tape (an IC mounting tape having a sprocket hole with or without a device hole and having a copper layer wiring pattern on both sides is referred to as 2 metal TAB). The flowchart of the typical manufacturing process is shown.

As shown in Fig. 1, a sprocket hole, in some cases a through hole and the like, is formed in a double-sided copper-clad polyimide tape by pressing, and through hole plating is performed. Thereafter, the surface is removed, a photoresist is applied, a wiring layer is formed on the surface by exposure, development, and etching, and then the wiring layer is also formed on the back surface in the same manner. Finally, a solder resist is applied by screen printing, and finish plating such as gold plating is performed to improve the conduction reliability.

And it is preferable to laminate | stack several sheets for the circuit board which has a wiring layer on both surfaces manufactured by such a method, or the circuit board which has a wiring layer on one side, and the mainstream of this conventional method is, for example, Unexamined-Japanese-Patent No. 8-125344. The build-up method disclosed in the call. This method is demonstrated based on FIG.2 (a)-FIG.2 (d).

First, the surface of the insulating substrate 1 coated with the first copper plating layer on one side is masked and etched to form a desired first wiring pattern 2 on the surface, and the cone-shaped material is formed on the wiring pattern 2. 1 Print the conductive bumps (3). Above the insulating substrate 1, the first insulating adhesive layer 4 having the second copper plating layer 2a coated on the upper surface in the same shape as the insulating substrate 1 is placed ((a) of FIG. 2), and When the insulating adhesive layer 4 is moved downward and pressed to the insulating substrate 1, the conical tip portion of the first conductive bump 3 is penetrated and planarized, and at the same time, the second copper passes through the insulating adhesive layer 4 In contact with the plating layer 2a (FIG. 2 (b)), the 1st laminated body 5 is comprised.

Subsequently, the surface of the 2nd copper plating layer 2a of the 1st laminated body 5 of FIG. 2 (b) is masked and etched, and the desired 2nd wiring pattern 2b is formed on this surface, and this wiring pattern 2b The second conductive bumps 3a having the same shape as the first conductive bumps are printed on the? Next, the 2nd insulating adhesive layer 4a which has the 3rd copper plating layer 2c on the upper surface is located above the 1st laminated body 5 (FIG.2 (c)).

When the second insulating adhesive layer 4a is moved downward and compressed to the first insulating adhesive layer 4, the cone tip of the second conductive bump 3a is penetrated and planarized, and at the same time, the second insulating adhesive layer ( The second laminate 5a is formed by penetrating through 4a to contact the third copper plating layer 2c, masking and etching the third copper plating layer 2c, and converting it into a desired third wiring pattern 2d. (FIG. 2 (d)).

As described above, in the conventional build-up method illustrated in FIG. 2, when the plurality of wiring patterns 2, 2b and 2d are formed on the insulating substrate 1 through the insulating adhesive layers 4 and 4a, Printing the conductive bumps in the same number of layers and pressing the insulating adhesive layer, that is, forming the wiring pattern and printing the conductive bumps for each layer is necessary.

In addition, the wiring pattern to be formed is subjected to miniaturization in accordance with recent miniaturization requirements, and it is not easy to perform bump formation corresponding to such a fine wiring pattern by a printing method. And it is very burdensome to carry out this printing method as many times as the number of layers of the wiring pattern, and the time and economic loss cannot be ignored when a large number of products have to be manufactured.

In order to meet such a request for fine wiring pattern printing, there is a need for a printer equipped with an image recognition device capable of securing not only high printing performance but also excellent image recognition performance and high position accuracy. However, such an apparatus is generally expensive, and the capital investment is enormous.

In the prior art shown in Fig. 2, the wiring pattern layer can be formed on the lower side of the insulating substrate 1 in the same manner, but in this case, the wiring pattern on the upper side and the wiring pattern on the lower side of the insulating substrate 1 are electrically connected. In order to make a connection, a through hole penetrating through the insulating substrate 1 must be formed, and not only the effort and time required for forming the through hole, but also the plating of the through hole is required, which greatly complicates the manufacturing process.

Accordingly, a first object of the present invention is to provide a circuit board, for example, a two-metal TAB tape, and a method of manufacturing the same, wherein a highly reliable electrical connection is formed between the conductor layers on both sides of the front and back.

The 2nd object of this invention is to provide the printed circuit board which can laminate | stack a plurality in a simple process, and the method of multilayering this several printed circuit board.

In the first embodiment of the present invention, the two wiring layers are electrically connected to each other by a conductor filled with an insulating substrate and wiring layers coated on both surfaces thereof and filled with a through hole formed by a punching press in the insulating substrate. There is a wiring board.

In the wiring board of the present embodiment, since the through hole for conductor charging connecting the wiring layers on both sides of the insulating board is formed and the filling of the conductor itself is performed by punching press, the conductor and the wiring layer are firmly in contact with each other to ensure the electrical connection between the wiring layers. Increased reliability

According to a second embodiment of the present invention, after forming wiring layers on both sides of an insulating substrate, a through hole penetrating the double wiring layer is formed by a punching press, and a conductor is filled in the through hole by the punching press to form the double wiring layer. A method of manufacturing a wiring board, characterized in that the connection is electrically made.

According to the method of this embodiment, since a conductor is filled in the wiring layer in which the through hole was formed, the wiring layer of the peripheral part of a through hole and the conductor filled in a through hole reliably contact, and the reliability of the electrical connection of both wiring layers becomes high.

According to the third embodiment of the present invention, a wiring layer is formed so that a through hole is formed in an insulating substrate by a punching press, a conductor is filled in the through hole by a punching press, and the wiring layer is brought into contact with open end faces of both surfaces of the insulating substrate. A method of manufacturing a wiring board, wherein the wiring board is formed to electrically connect both wiring layers.

According to the method of this embodiment, a conductor is filled in the through-hole opening toward both surfaces of the insulating substrate so that both ends thereof match with both sides of the insulating substrate, and wiring layers are formed on both sides of the insulating substrate so as to contact both ends of the conductor. Therefore, the reliability of the electrical connection of both wiring layers becomes high.

A fourth embodiment of the present invention includes an insulating sheet having a wiring pattern formed on both surfaces or one side thereof, a conductor filled in the wiring pattern and a through hole passing through the insulating sheet, and at least one end surface of the conductor It is a printed circuit board which protrudes from the mating surface with the said insulating sheet and / or a wiring pattern.

A fifth embodiment of the present invention includes an insulating sheet having a wiring pattern formed on both surfaces or one side thereof, a conductor filled in the wiring pattern and a through hole passing through the insulating sheet, and at least one end surface of the conductor A multilayer printed wiring board comprising a plurality of printed circuit boards having protruding portions from mating surfaces of the insulating sheet and / or wiring patterns stacked through a dielectric adhesive layer, and the plurality of printed circuit boards compressed and stacked together. .

The printed circuit board of 4th Embodiment is especially useful as an intermediate body which laminated | stacks and manufactures a multilayer printed wiring board.

When the printed circuit board of this 4th Embodiment is laminated | stacked through several sheets and an insulation adhesive layer, and these are crimped | bonded, the multilayer printed wiring board of 5th Embodiment which was collectively laminated | stacked is obtained.

At this time, the protruding portion of the conductive material penetrates the insulating adhesive layer and electrically contacts the wiring pattern of the adjacent unit board or the conductive material, so that the adjacent unit boards, that is, all the printed circuit boards of the multilayer stack are connected in a desired electrical relationship. In addition, if necessary, connection between the upper and lower wiring patterns of each unit substrate can be ensured at the same time.

By properly setting the number and positions of the conductive materials to be filled in the through holes of each unit substrate, the multilayer printed wiring board having the desired wiring pattern and electrical connection can be collectively laminated in a single crimping operation.

In a sixth embodiment of the present invention, a through hole in which an electric conductor is filled in an insulating sheet having wiring patterns formed on both surfaces or one side thereof is formed such that at least one of both ends of the conductor protrudes from the surface of the wiring pattern and / or the insulating sheet. To form a printed circuit board, and a plurality of these printed circuit boards are laminated through an insulating adhesive layer, and the plurality of stacked printed circuit boards are crimped so that the protruding portions of the conductors penetrate the adhesive layer to adjoin the wiring pattern of the printed circuit board. And / or contacting a conductive material to form electrical connections between adjacent wiring patterns.

The method of this embodiment can laminate | stack a multilayer printed wiring board collectively as a single crimping operation as mentioned above, and compared with the conventional buildup method, a process is very simple and cost reduction is attained. Moreover, since it can be manufactured dry, waste liquid does not generate | occur | produce, it is possible to recycle the used material, and it is an excellent method from an environmental conservation viewpoint.

Through-hole formation and conductive material filling in the method of the present invention are preferably carried out by punching, and the punching method can be positioned with higher accuracy than the printing method, and thus is suitable for achieving the miniaturization required in recent years of printed wiring boards.

The present invention includes a printed circuit board, a TAB tape using flexible polyimide, and the like, a multilayer wiring board using a fixed substrate such as glass epoxy, in addition to CSP, BGA, and FPC.

Embodiment related to electrical connection formation by punching press

In the embodiment of the present invention in which the through hole is formed and the conductor filling into the through hole is performed by punching press, the through hole is formed in the insulating substrate or in the insulating substrate having the wiring layer formed by the punching press. A punching press is also used to fill the formed through hole with the conductor. By using a punching press, through-hole formation and conductor filling to the through-holes can be reliably performed. Therefore, the reliability of the electrical connection between the wiring layers on both sides of the previously formed insulating substrate and the wiring layers formed on both sides of the insulating substrate after conductor charging are improved.

Thus, in this embodiment, the formation of the wiring layer on both surfaces of the insulating substrate may be either before or after through hole formation, and if the wiring layer is formed before the through hole formation, it is necessary to form the through hole so as to pass through the insulating substrate and both wiring layers. When the through-holes are filled with a punching press, the conductors in the vicinity of both ends of the through-holes contact the wiring layers at the periphery of the through-holes, so that the wiring layers on the front and back surfaces are reliably electrically connected through the conductors.

An example in which the wiring layer is formed before the through hole formation will be described based on FIGS. 3A to 3D.

As shown in Fig. 3A, the wiring layers 12a and 12b are formed on the surface of the insulating substrate 11 and the wiring layers 12c and 12d are formed on the rear surface thereof, and the wiring layers 12a and 12a are electrically connected to each other. The positions corresponding to 12c and the wiring layers 12b and 12d are punched out by the punches 13a and 13b to form two through holes 14a and 14b as shown in Fig. 3B. At this time, since it is through-hole formation by punching press, it hardly comes out as a smear, and operation of a desmear becomes unnecessary.

Subsequently, the rectangular parallelepiped raw material conductors 15a and 15b are disposed to cover each of the formed through holes 14a and 14b (see Fig. 3 (c)), and the same punches 13a and 13b as in the through hole formation. When the punching press is carried out using, the raw material conductors 15a and 15b are pressed downward to fill the through holes 14a and 14b as connection conductors 16a and 16b (see Fig. 3 (d)). In the through hole filling by this punching press, it is preferable that the through holes 14a and 14b are reliably filled with a conductor, and the conductors protruding from the through holes are removed by polishing or the like so that the surfaces of the conductor and the wiring layer are matched.

Next, the example which forms a wiring layer after through-hole formation is demonstrated based on FIG.4 (a)-(e). In this example, the example of FIG. 3 is improved, and the same members are denoted by the same reference numerals, and description thereof is omitted.

As shown in Fig. 4A, punching presses are formed by punches 13a and 13b at the positions where the wiring layer is formed behind the surface of the insulating substrate 11, and two through-holes as shown in Fig. 4B. The holes 14a and 14b are formed. At this time, since the hole is formed by the punching press, smear does not come out.

Subsequently, the rectangular parallelepiped raw material conductors 15a and 15b are disposed so as to cover each of the formed through holes 14a and 14b (see Fig. 4C), and the same punches 13a and 13b as in the through hole formation. When the punching press is carried out using, the raw material conductors 15a and 15b are pressed downward to fill the through holes 14a and 14b as connection conductors 16a and 16b (see Fig. 4 (d)). In the through hole filling by this punching press, it is preferable that the through holes 14a and 14b are reliably filled with a conductor, and the conductors protruding from the through holes are removed by polishing or the like so that the surfaces of the conductor and the wiring layer are matched.

  Thereafter, the wiring layers 12a and 12b are positioned at the positions corresponding to the through holes 14a and 14b on the front side of the insulating substrate 11, and the wiring layers 12c are positioned at the positions corresponding to the through holes 14a and 14b on the back side. And 12d), as shown in Fig. 4E, the inner surfaces of the wiring layers 12a and 12c are connected to each other by the connecting conductor 16a and the wiring layers 12b and 12d of the insulating substrate 11, respectively. Circuit boards, for example, two metal TAB tapes, in which respective inner surfaces are connected to each other by the connecting conductor 16b, can be produced.

5 (a) and 5 (b) show another example of circuit board fabrication, and the same reference numerals are used for the same members as in FIGS. 3 (a) to 3d and 4 (a) to 4 (e). The description is omitted.

In this example, as shown in Fig. 5 (a), of the wiring layers 12a, 12b, 12c, and 12d formed on the front and back surfaces of the insulating substrate 11, a rectangular parallelepiped shape is formed on the wiring layers 12a and 12b on the surface side. When the raw material conductors 15a and 15b are disposed and punched presses are performed using the punches 13a and 13b, through holes are formed and the through holes are filled with the raw material conductors so that the corresponding double wiring layers 12a, 12b, 12c and 12d) The connection conductors 16a and 16b are filled, and the corresponding double wiring layers 12a, 12b, 12c, and 12d are electrically connected.

In this example, operation of the punching press is completed once and the operability is improved.

FIG. 6: is a longitudinal cross-sectional view which illustrates the circuit board 11a produced by the process of FIG. 3 (a)-(d), FIG. 7 is a circuit board 11b produced by the process of FIG. 5 (a) and (b). Is a longitudinal sectional view illustrating the

In the circuit board of FIG. 6 showing the case of a through-hole having a diameter of 200 μm manufactured by a two-stage punching press, the wiring layer 12f on the back side of the insulating substrate 11a is reliably in contact with the through hole by the first punching press. Since the connection conductor 16c is formed by filling the raw material conductor in the through hole by the second punching press, the connection conductor 16c contacts the wiring layer 12f on the back side, and this back side The wiring layer 12f is electrically connected to the wiring layer 12e on the surface side by this connecting conductor 16c.

In contrast, in the circuit board of FIG. 7 produced by a single punching press, the connecting conductor 16d is pressed by pressing the raw material conductor downward with a punching press and pressing the conductor into a position corresponding to the through hole of the insulating substrate 11b. Since the portion of the insulating substrate 11b removed by the punching press is deformed by pressing the wiring layer 12f in the downward and transverse directions, the connection conductor 16d and the wiring layer 12f on the back side do not come into contact with each other. Therefore, the electrical connection may not be secured. Therefore, in the manufacture of the circuit board, it is preferable to employ the two-stage punching press of FIGS. 3A to 3D and 4A to 4E. However, even in the case of the single punch punching press of FIG. By selecting conditions such as the thickness of the substrate, it is possible to secure the electrical connection.

The punching press used for the punching press only needs to use a general machine and can fill the through hole only by the punching press, so that the electrical connection between the front and back surfaces of the circuit board can be reliably achieved at low cost.

Although the process itself of the above embodiment is simple, the selection and setting of post-processing such as (1) the thickness of the substrate and the thickness of the conductor to be filled, (2) the material and hardness of the conductor, (3) the punching stroke, (4) the caulking, etc. are important.

The optimum area exists in the thickness t1 of the conductor and the thickness t2 of the insulating substrate, preferably 1.4 x t2? T1? 0.7 x t2, more preferably 1.3 x t2? T1? 0.8 x t2. For example, 1.2 × t2 ≧ t1 ≧ 0.9 × t2. This is because, depending on the caulking conditions described later, if the conductor is too thick, irregularities will occur on the surface of the substrate, causing problems in dimensional accuracy, and if too thin, electrical connection with the wiring layer will be insufficient.

As for the material of the conductor, if the hardness is too high, unevenness occurs in the substrate itself, which is not preferable. Although the solder is flexible and can be used as it is, in the case of copper foil, it is preferable to conduct a study of softening by annealing or the like. It is also advantageous to be able to recycle the solder at cost.

Since the optimum stroke varies depending on the quality and thickness of the substrate or conductor, it is desirable to actually punch and set an empirically desirable range, so that the conductor is stuck to a so-called skewer in the substrate. Set the appropriate punching stroke.

The caulking treatment after conductor charging is a process that determines the reliability of conduction, and is required to smoothly carry out the subsequent steps and conveyance after the conductor is embedded. For example, a tape-shaped substrate is often wound on a reel or the like in a subsequent step, but a caulking treatment is also preferable for improving durability against such bending.

In the case of using a low melting point metal or an alloy such as solder as the conductor, the number of steps is increased, but the electrical connection is more secured once the charged conductor is reflowed.

Embodiment of a multilayer laminated printed circuit board

Next, an embodiment of the present invention in which a plurality of printed circuit boards are laminated is described.

In the present embodiment, instead of the printing method of conducting the conductive bumps in the conventional build-up method, a through hole is formed by punching or the like in a portion of the insulating sheet on which a conductive material corresponding to the conventional conductive bumps is formed. A printed circuit board (unit board) is used in which a hole is filled with the conductive material and at least one of both ends of the conductive material in the through hole protrudes from a wiring pattern or an insulating sheet surface.

In the present progress of miniaturization of wiring patterns, it is easier and more accurate to form through holes by punching or the like than to form conductive bumps by printing.

When a plurality of unit substrates having the protruding portions are laminated through the insulating adhesive layer and each unit substrate is pressed, the protruding portions penetrate the insulating adhesive layer to electrically connect wiring patterns or conductive materials between adjacent unit substrates. Therefore, regardless of the number of unit boards, it is possible to easily manufacture a multilayer printed wiring board by electrically connecting the unit boards together in a single operation for crimping each unit board.

The conductive material filled in the through hole of the unit board not only connects the wiring patterns of the adjacent unit boards but also electrically connects the wiring patterns above and below the charged unit boards. As the conductive material, lead, tin, copper, nickel, or an alloy containing these as a main component, for example, solder or lead-free solder, is suitable. In addition, precious metals such as indium, gold, and silver can also be used.

The unit substrate used in the present invention can be used without limitation the material of the material used as a substrate in a conventional printed circuit board, for example, the use of polyimide resin is preferred. In addition, the material and the formation method of a wiring pattern are not specifically limited, What is necessary is just to form a copper plating layer, and to create a desired wiring pattern by masking, exposure, image development, and etching by application | coating of a photoresist. If necessary, a wiring pattern may be formed on the other surface of the unit substrate in the same manner to form a unit substrate having wiring patterns on both surfaces.

The number of through holes to be generated depends on the number and positional relationship of wiring patterns requiring electrical connection, and the diameter is preferably as small as possible in a range where sufficient electrical connection is secured.

Through-hole formation to the unit substrate and the filling of the conductive material into the through-holes are preferably carried out by filling the through-holes with a die or the like, and then filling the through-holes with the conductive material. At the same time as the through hole is opened, a conductive metal sheet (the same material as the conductive material) placed between the mold and the unit substrate may be entered into and filled by the punching press. However, when the through hole formation and the conductive material filling are performed in a single operation, the tip of the formed protrusion tends to be rounded, and thus, the conduction reliability is easily degraded. It is preferable.

The punching which is preferably used for forming the through-hole and filling the conductive material can be performed in the same manner as in the above-described embodiment, but the operation itself is simple, but the thickness of the conductive material (t1) excluding the thickness of the protrusion and the insulating sheet of the unit substrate It is necessary to pay attention to the relationship between the thickness t2 and the selection and setting of post-processing such as caulking and the like in the above-described embodiment.

Although the protrusion length of the protrusion formed in at least one of the upper and lower sides of a conductive material depends on the thickness of the insulating adhesive layer to be used, about 10-500 micrometers is suitable normally. Depending on the electrical connection required, the protruding portion may be formed above or below the conductive material, and in the case of forming a plurality of conductive materials, the protruding portion may not be formed on some of them.

As the insulating adhesive layer, it is preferable to use a thermosetting resin, so-called prepreg, which is not completely cured. In addition, a hot melt type, that is, a thermoplastic resin, may also be used.

Since the conductive material and the wiring pattern in the through hole are not necessarily electrically connected to each other, a plating layer is formed so as to span the conductive material and the wiring pattern, or both or one side of the contact interface is alloyed by reflowing them. The electrical connection may be made more reliable. In order to make the contact interface more certain, plating of gold or the like on the protruding portion and tin plating on the circuit portion serving as the connection pad may be considered to make contact with the low-melting eutectic alloy, if necessary. Moreover, it is also possible to use together ultrasonic welding etc. apparatus.

The multilayer printed wiring board manufactured by this embodiment is applicable to various printed circuit boards using fixed circuit boards, such as TAB tape, CSP, BGA, FPC, and glass epoxy, similarly to the above-mentioned embodiment.

Next, although embodiment of manufacture of the printed circuit board which concerns on this embodiment is described based on an accompanying drawing, this embodiment does not limit this invention.

8A to 8E are longitudinal cross-sectional views illustrating a series of manufacturing steps of a single printed circuit board (unit board).

A laminate (CCL, Cupper Crad Laminate) called a two-layer type in which the copper plating layer 22 is coated on the upper and lower surfaces of the insulating sheet 21 made of polyimide or the like is used (Fig. 8 (a)). Instead of the two-layer type, a three-layer type in which an adhesive layer is placed between the insulating sheet 21 and the copper plating layer 22 may be used. However, the adhesive may be attached to the punch to be used, thereby degrading operability. .

The copper plating layer 22 is masked and etched with a suitable reagent to form a wiring pattern 23 (Fig. 8 (b)). After this operation, a through hole is formed by any of two separate methods (Fig. 8 (c) or Fig. 8 (d)), and the through hole is filled with a conductor.

In the method shown in FIG. 8C, the conductive metal sheet 24 made of a metal of the same material as that of the conductor is positioned apart from the insulating sheet 21 on which the wiring pattern 23 is formed. The punching mold 25 having the same diameter as that of the through hole is opened for opening thereon, and the conductive metal sheet 24, the wiring pattern 23, and the insulating sheet 21 are punched by the mold 25 with a press. By opening the through hole 26 in the wiring pattern 23 and the insulating sheet 21, the conductive metal sheet 24 enters the through hole 26, thereby allowing the through hole 26 to be electrically conductive. A part of the metal sheet is filled with a conductive material 27, and a tip portion of the conductive material 27 forms a projection 28 protruding from the wiring pattern 23 below to constitute the unit substrate 29 ( 8 (e)).

On the other hand, in the method shown in (d) of FIG. 8, through-hole 26 is used for the insulating sheet 21 with wiring pattern 23 of FIG. 8 (b) using the same mold as that of FIG. After the opening is made, the conductive metal sheet 24 is positioned above the insulating sheet 21, the mold 25 used to form the through hole 26 is positioned, and the conductive metal sheet is formed into the mold 25 by a press. The sheet 24 is punched to fill the through hole 26 with a portion of the conductive metal sheet 24, and the protruding portion 28 in which the distal end portion of the conductive material 27 protrudes from the lower wiring pattern 23 is formed. To form the unit substrate 29 (Fig. 8 (e)).

9 (a) and 9 (b) are longitudinal cross-sectional views illustrating a method of manufacturing a multilayer laminated printed wiring board by collectively stacking the unit substrates manufactured in FIGS. 8 (a) to 8 (e) and FIG. 9 (a). (B) before lamination, (b) shows each state after lamination | stacking.

In Fig. 9A, four unit substrates are separated from each other, and the uppermost unit substrate 29 is the same as the unit substrate 29 in Fig. 8E. The other three unit boards 29a, 29b, 29c are the same as the top unit board except that the wiring patterns and the opening positions of the through holes are different. Each member of the unit substrates 29a, 29b, 29c other than the topmost one has a subscript (a, b, c) attached to each code of the member attached to the topmost unit substrate 29, and description thereof is omitted. In addition, although the figure shows that the wiring pattern 23 was already formed as the uppermost unit board | substrate 29, only the uppermost unit board | substrate 29 does not form the wiring pattern 23, and laminates collectively after that. The wiring pattern 23 may be formed on the unit substrate 29.

Three insulating adhesive layers 30, 30a, and 30b are positioned between the four unit substrates 29, 29a, 29b, and 29c which are stacked in this order in order, and the through hole on the left side of the uppermost unit substrate 29 ( 26 and the through hole 26a on the left side of the second unit substrate 29a are at the same position, and the other through hole 26a of the second unit substrate 29a is formed on the third unit substrate 29b. At the same position as the through hole 26b on the left side, another through hole 26b of the third unit substrate 29b is at the same position as the through hole 26c on the right side of the lowermost unit substrate 29c.

When the four unit substrates and the three insulating adhesive layers are placed in a press having a heating, pressurizing and cooling mechanism, heated and pressurized, pressed, stacked together, cooled in a pressurized state, and then taken out from the press The multilayer printed wiring board 31 can be obtained as shown in Fig. 9B.

In the obtained multilayer printed wiring board 31, the following electrical connections are formed. In other words, the lower end protruding portion 28 of the conductive material 27 in the left through hole 26 in the drawing of the uppermost unit substrate 29 in FIG. 9A shows the uppermost insulating adhesive layer 30. The new conductive material 27 + 27a is formed by integrating with the conductive material 27a in the through hole 26a on the left side of the second unit substrate 29a through the through hole to form the wiring pattern 23 of the uppermost unit substrate 29. ) Is electrically connected to the wiring patterns 23a and 23b of the second and third unit substrates 29a and 29b. In the same manner, the projection 28a of the conductive material 27a in the through hole 26a on the right side of the second unit substrate 29a in Fig. 9A is the left side of the third unit substrate 29b. The new conductive material 27a + 27b is integrated with the conductive material 27b of the through hole 26b of the second through hole 26b, so that the wiring pattern 23a of the second unit board 29a is the third and lowest unit boards 29b, It is electrically connected with the wiring patterns 23b and 23c of 29c. In the same way, a new conductive material 27b + 27c is formed between the third and lowest unit substrates 23b, 23c.

Further, for example, even if not integrated with another conductive material, such as the conductive material 27 in the through hole 26 on the right side of the uppermost unit substrate 29 in FIG. By contacting the wiring pattern 23a of the second unit substrate 29a through the adhesive layer 30, an electrical connection is formed between the uppermost and second unit substrates 29, 29a.

By adjusting the position of the through hole formed in each unit substrate in this manner, arbitrary portions of the wiring patterns having various shapes of the plurality of unit substrates can be electrically connected, and each layer (each Effort and time can be dramatically improved because a plurality of unit boards can be stacked together without effort and time such as printing conductive bumps for each unit board).

On the formation of electrical connection by punching press Example

Example 1

The 2-metal TAB tape was manufactured by the operation shown next.

According to the process shown in FIG. 1 using the 36-mm-width double-sided copper adhesive polyimide film (50 micrometers in thickness of a polyimide layer, each 18 micrometers of copper foil thickness; Shin Nippon Kagaku Co., Ltd. make, brand name Espanex), FIG. A two metal TAB tape as shown in 10 and FIG. 11 was produced. FIG. 10 is a plan view of the produced 2-metal TAB tape, and FIG. 11 is a rear view of the 2-metal TAB tape. 12 is an enlarged view of the surface side land of the two-metal TAB tape of FIG. 10, and FIG. 13 is an enlarged view of the back side land of the two metal TAB tape of FIG. 11. In addition, a land means the place where a through hole is formed and a conductor is filled. 10 to 13, reference numeral 41 denotes a two-metal TAB tape, 42 denotes a sprocket hole, 43 denotes a land, and 44 denotes a wiring layer.

Through holes were formed by punching presses at positions corresponding to the lands 43 of the two-metal TAB tapes 41 on which the wiring layers were formed by etching shown in FIGS. 10 and 11. Subsequently, a solder plate having a thickness of 95 µm was superimposed on the tape 41 to form a punching press again, whereby the solder was filled in the through hole, and then the wiring layer between front and rear surfaces was electrically connected by caulking by the same press. As shown in FIG. 6, the wiring layer and the conductor contacted the 2 metal TAB tape obtained by such a method reliably, and sufficient conduction (<10 mPa / hole) was obtained as a 2 metal TAB tape in any through hole.

Example 2

A two-metal TAB tape was produced in the same manner as in Example 1 except that the filling of the conductor into the through hole was not performed after the wiring layer was formed, but the conductor was filled at the same time as the sprocket hole was formed after the through hole was formed in advance. Also in this example, the wiring layer and the conductor reliably contacted each other, and sufficient conduction (<10 mPa / hole) was obtained as a two-metal TAB tape in any through hole.

Comparative Example 1

A 2-metal TAB tape was produced in the same manner as in Example 1 except that through-hole formation and solder filling were simultaneously performed by punching press without forming a through-hole in advance. As a result, as shown in FIG. 7, the disconnection of the wiring layer and the conductor was observed, and sufficient conduction was not obtained as a 2 metal TAB tape.

Comparative Example 2

A 2-metal TAB tape was produced in the same manner as in Example 2, except that through-hole formation and solder filling were simultaneously performed by punching press without forming a through-hole in advance. As a result, in the same manner as in Comparative Example 1, disconnection between the wiring layer and the conductor was observed, and sufficient conduction was not obtained as the two-metal TAB tape.

Multilayer Laminated printing  Circuit board Example

Example 3

Although the embodiment which manufactures a multilayer printed wiring board by the method shown in FIG. 8 and FIG. 9 is described, this embodiment does not limit this invention.

400 through holes of a diameter of 0.1 mm were formed through a CCL of a two-layer type by forming a wiring pattern by patterning a copper adhesive layer on both surfaces of a polyimide resin having a thickness of 25 µm. The CCL is placed on a conductive metal sheet made of a high temperature solder, and the sheet is punched using the die, so that the upper surface of the CCL is matched with the CCL so that the bottom surface protrudes from the CCL by about 100 μm. It embedded in the hole and used as the unit board | substrate.

Four such unit substrates were laminated through a thermosetting adhesive layer (prepreg) containing no three glass fibers having a thickness of about 40 µm, and placed in a press having a heating, pressing, and cooling mechanism, and the temperature was set to 150 ° C and 2 degrees. The mixture was heated and pressurized at atmospheric pressure for 10 minutes, and laminated at once, and cooled to room temperature over 10 minutes while maintaining pressurization.

The electrical resistance between the wiring patterns on the upper and lower surfaces of the unit substrate of the obtained multilayered multilayer printed wiring board and the electrical resistance between the wiring patterns between the adjacent unit substrates through the adhesive layer were both low resistance of an average of 2 mΩ.

In order to test the reliability of the electrical connection, the obtained multilayer printed wiring board was immersed in 260 ° C. for 10 seconds in oil and then immersed in 20 ° C. in oil for 20 seconds for 100 cycles. Even after the test was completed, no defect occurred in the multilayer printed circuit board, and reliability was confirmed.

As described above, according to the present invention, it is possible to achieve high reliability electrical connection between circuit boards formed between the conductor layers on both sides of the front and back. Moreover, according to this invention, a plurality of printed circuit boards can be laminated by a simple process.

1 is a flowchart showing a process for producing a 2-metal TAB tape.

(A)-(b) is a longitudinal cross-sectional view which shows the series process which manufactures a multilayer laminated printed wiring board by the conventional buildup method.

3A to 3D are longitudinal cross-sectional views showing a series of steps for forming a wiring layer before through hole formation in an embodiment relating to electrical connection formation by punching presses.

Fig.4 (a)-(e) is a longitudinal cross-sectional view which shows a series of process of similarly forming a wiring layer after through-hole formation.

5A and 5B are longitudinal cross-sectional views illustrating a process of forming an electrical connection with a single punching press;

FIG. 6 is a longitudinal cross-sectional view illustrating an insulating substrate produced by the process of FIGS. 3A to 3D.

FIG. 7 is a longitudinal cross-sectional view illustrating an insulating substrate produced by the process of FIGS. 4A to 4E.

8A to 8E are longitudinal cross-sectional views illustrating a series of manufacturing steps for a single printed circuit board.

9 (a) and 9 (b) are longitudinal cross-sectional views illustrating a method of manufacturing a multilayer laminated printed wiring board by collectively stacking the unit substrates manufactured in FIGS. 8 (a) to 8 (e) and FIG. 9 (a). (B) before lamination, (b) shows each state after lamination | stacking.

10 is a plan view illustrating a two-metal TAB tape produced in the Example.

FIG. 11 is a rear view illustrating the two metal TAB tape produced in the Example. FIG.

12 is an enlarged view of the surface side land of the 2 metal TAB tape of FIG. 10;

FIG. 13 is an enlarged view of the back side land of the 2 metal TAB tape of FIG. 11; FIG.

* Brief description of the main parts of the drawing *

11: board 12a, 12b, 12c, 12d: wiring layer

13a, 13b: Punch 14a, 14b: Through Hole

15a, 15b: raw material conductors 16a, 16b: connection conductors

Claims (5)

An insulating sheet having wiring patterns formed on both surfaces thereof, and a conductor filled in the wiring pattern and a through hole passing through the insulating sheet, and at least one end surface of the conductor protrudes from a mating surface with the wiring pattern. And the through-hole formation and the conductor filling are performed by punching. An insulating sheet having wiring patterns formed on both surfaces thereof, and a conductor filled in the wiring pattern and a through hole penetrating through the insulating sheet, wherein at least one end surface of the conductor is projected from the mating surface with the wiring pattern. A plurality of printed circuit boards having a plurality of printed circuit boards having a plurality of printed circuit boards; and a plurality of printed circuit boards compressed and stacked together, and the through hole formation and the conductor filling are performed by punching. . A through hole filled with a conductor is formed in an insulating sheet having wiring patterns formed on both surfaces thereof, so that at least one of both ends of the conductor protrudes from the surface of the wiring pattern to form a printed circuit board, and the plurality of printed circuit boards are formed of an insulating adhesive layer. Laminated through the plurality of printed circuit boards, and the protrusions of the conductors penetrate through the adhesive layer to contact the wiring patterns of the adjacent printed circuit boards and / or And forming the through hole and filling the conductor by punching. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein said through hole formation and said conductor filling fill said conductor in said through hole after forming said through hole. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein the through hole formation and the conductor filling fill the conductor into the through hole simultaneously with the through hole formation.