JPH0974285A - Multilayer printed wiring board and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer printed wiring board possessed of fine and accurate wiring pattern layers which are easily connected together and high in adhesion to a board, wherein the multilayer printed wiring board can be easily manufactured through a transfer lamination method that wiring pattern layers are transferred onto a board as laminated without employing a photolithography process. SOLUTION: A process, wherein wiring pattern layers 3, 4, and 5 are transferred onto a board 2 by the use of a wiring pattern layer transfer plate equipped with wiring pattern layers 3, 4, and 5 possessed of electron-beam curing insulating resin layers 3b, 4b, and 5b on conductive layers, is successively carried out for each of wiring pattern layer transfer plates, and the insulating resin layers 3b, 4b, and 5b are cured by irradiation with art electron beam at the transfer of the wiring pattern layers 3, 4, and 5, whereby the wiring pattern layers 3, 4, and 5 possessed of the insulating resin layers 3b, 4b, and 5b fixed to the board 2 high in adhesive power and conductive layers are formed on the board 2 for the formation of a multilayer printed wiring board 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board and a method for manufacturing the same, and more particularly to a multilayer printed wiring board having a high-definition pattern and having excellent insulation performance between wiring pattern layers, and The present invention relates to a manufacturing method capable of manufacturing such a multilayer printed wiring board easily and at low cost.

[0002]

2. Description of the Related Art Due to the rapid development of semiconductor technology, downsizing of semiconductor packages, increase in pin count, fine pitch,
The miniaturization of electronic components has rapidly progressed, and the era of so-called high-density mounting has entered. Along with that, printed wiring boards are being further multilayered and thinned from single-sided wiring to double-sided wiring.

At present, a subtractive method and an additive method are mainly used for forming a copper pattern on a printed wiring board.

The subtractive method is a method in which a hole is formed in a copper-clad laminate, copper is plated on the inside and the surface of the hole, and a pattern is formed by photoetching. Although this subtractive method is technically highly complete and inexpensive, it is difficult to form a fine pattern due to restrictions such as the thickness of the copper foil.

On the other hand, in the additive method, a resist is formed on a portion other than a circuit pattern forming portion on a laminated plate containing a catalyst for electroless plating, and a circuit is formed on the exposed portion of the laminated plate by electroless copper plating or the like. This is a method of forming a pattern. Although the additive method can form a fine pattern, it is difficult in terms of cost and reliability.

In the case of a multi-layer substrate, a method of pressure laminating a single-sided or double-sided printed wiring board produced by the above method or the like together with a semi-cured prepreg obtained by impregnating glass cloth with an epoxy resin or the like is preferred. It is used. In this case, the prepreg plays a role of an adhesive for each layer, and the connection between layers is made by forming a through hole and applying electroless plating or the like inside.

Further, due to the progress of high-density mounting, thin and lightweight multi-layer boards are required, and on the other hand, high wiring capability per unit area is required.
Ingenuity has been made in the connection between layers and the mounting method of parts.

[0008]

However, the production of a multilayer substrate using the double-sided printed wiring board produced by the subtractive method described above requires the precision of drilling for forming holes in the double-sided printed wiring board and the There is a limit to the densification from the viewpoint of the limit of materialization, and it was difficult to reduce the manufacturing cost.

On the other hand, in recent years, in order to satisfy the above requirements, a multilayer wiring board manufactured by sequentially laminating a conductor pattern layer and an insulating resin layer on a base material has been developed.
Since this multilayer wiring board is manufactured by alternately performing photoetching of the copper plating layer and patterning of the photosensitive resin, high-definition wiring and interlayer connection at arbitrary positions are possible.

However, in this method, copper plating and photo-etching are performed alternately a plurality of times, which complicates the process. In addition, if a trouble occurs in an intermediate process due to a series process of stacking one layer on a substrate, Reproduction becomes difficult, which hinders reduction in manufacturing cost.

Further, in the conventional multilayer wiring board, since the interlayer connection is made by forming via holes, a complicated photolithography process is required, which is an obstacle to the reduction of manufacturing cost.

The present invention has been made in view of such circumstances, has a high-definition pattern, has high adhesion between a wiring pattern layer and a substrate, and facilitates connection between wiring pattern layers. It is an object of the present invention to provide a multilayer printed wiring board having the above, and a manufacturing method capable of easily manufacturing such a multilayer printed wiring board by a transfer laminating method onto a substrate without including a photolithography step.

[0013]

In order to achieve such an object, a multilayer printed wiring board according to the present invention comprises a substrate and a plurality of wiring pattern layers sequentially transferred onto the substrate. Has a conductive layer and an insulating resin layer formed under the conductive layer, and the insulating resin layer is configured by curing an electron beam curing type insulating resin.

Further, the multilayer printed wiring board of the present invention has a portion where the wiring pattern layers intersect with each other and / or a portion where the wiring pattern layers are adjacent to each other, and at the intersection, insulation between upper and lower wiring pattern layers is an upper wiring pattern. A structure such that it is retained by an insulating resin layer that constitutes a layer, the intersection and /
Alternatively, a configuration is adopted in which a bonding portion is provided so as to straddle between the conductive layers that form the wiring pattern layer in the necessary portion of the proximity portion.

In the method for manufacturing a multilayer printed wiring board according to the present invention, a pattern made of an insulating material is formed on a transfer substrate having at least a conductive surface, and a wiring pattern portion on the transfer substrate where the pattern is not formed is formed. A plurality of wiring pattern layer transfer plates are prepared by forming a conductive layer so that it can be peeled off by a plating method and forming an electron beam curing type insulating resin layer on the conductive layer, and then, for a multilayer printed wiring board. Crimp the wiring pattern layer transfer plate to one surface of the substrate,
The operation of irradiating an electron beam from the back surface side of the substrate to cure the insulating resin layer, and then repeating the operation of transferring the wiring pattern layer onto the substrate by peeling off the transfer substrate is repeated on the substrate. The structure is such that a plurality of the wiring pattern layers are formed.

Further, in the method for manufacturing a multilayer printed wiring board according to the present invention, between the conductive layers forming each wiring pattern layer at necessary portions of the portion where the wiring pattern layers intersect and / or the portions where the wiring pattern layers are close to each other. The wiring pattern layers are connected to each other by forming the bonding portion so as to extend over the wiring pattern layers.

In the present invention, the wiring pattern layer transfer plate having the wiring pattern layer having the electron beam curing type insulating resin layer on the conductive layer is used to transfer a plurality of wiring pattern layers onto the substrate. Since this multilayer printed wiring board is formed, it has a so-called overprint type structure. When the wiring pattern layer is transferred, the insulating resin layer is cured (aggregated) by being irradiated with an electron beam. Adhesion to the substrate is extremely high, and the conductive layer of each wiring pattern layer is always exposed partially, and at the portion where each wiring pattern layer intersects or overlaps, the upper insulating resin layer is used. The wiring pattern layers are surely insulated from each other, and the plating and photoetching steps on the substrate are not necessary, and the manufacturing method of the multilayer wiring board can be simplified.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of the multilayer printed wiring board of the present invention. In FIG. 1, a multilayer printed wiring board 1 includes a substrate 2, a first-layer wiring pattern layer 3 provided on the substrate 2, and a second-layer wiring pattern formed on the wiring pattern layer 3. The layer 4 and the third wiring pattern layer 5 formed on the wiring pattern layer 4
It is a multi-layer printed wiring board having a three-layer structure including.

The wiring pattern layers 3, 4 and 5 constituting the multilayer printed wiring board 1 are made of conductive layers 3a and 4 respectively.
a, 5a and insulating resin layers 3b, 4b, 5b formed under the conductive layer.

The above-mentioned multilayer printed wiring board 1 has an overprint type structure in which the wiring pattern layers 3, 4, and 5 are sequentially transferred onto the substrate 2 or onto the lower wiring pattern layer. At the portions where the layers intersect or overlap with each other (hereinafter referred to as intersections), the wiring pattern layers are reliably insulated by the insulating resin layers 4b and 5b forming the upper wiring pattern layer. In the multilayer printed wiring board 1 of the present invention, the insulating resin layers 3b, 4b, 5b are
It is formed by curing an electron beam curing type insulating resin in a transfer step of a wiring pattern layer described later. For this reason,
The adhesion between the substrate 2 and the insulating resin layers 3b, 4b, 5b becomes extremely high, and the multilayer printed wiring board 1 becomes excellent in durability.

Further, the multilayer printed wiring board 1 of the present invention is
Since the wiring pattern is not covered with the insulating resin layer as seen in the conventional multilayer printed wiring board, the conductive layers 3a, 4a, 5a of the wiring pattern layers 3, 4, 5 are always partially exposed. Therefore, as will be described later, it is possible to easily connect the wiring pattern layers to each other at the intersections of the wiring pattern layers or the portions (proximity portions) where the wiring pattern layers are close to each other.

The substrate 2 constituting the multilayer printed wiring board 1 of the present invention may be a substrate known as a substrate for a multilayer printed wiring board, such as a glass epoxy substrate, a polyimide substrate, an alumina ceramic substrate, a composite substrate of glass epoxy and polyimide. Can be used. Alternatively, as the substrate 2, a semi-cured prepreg substrate obtained by impregnating glass cloth with epoxy resin may be used. In order to cure the insulating resin layer by electron beam irradiation from the back surface of the substrate 2 at the time of transferring a wiring pattern layer, which will be described later, the thickness of the substrate 2 needs to be a thickness through which the electron beam can pass. Yes 1
˜1000 μm, preferably 5 to 100 μm.

The thickness of each of the wiring pattern layers 3, 4, and 5 is 100 μm or less, preferably 10 μm or less, so that the wiring pattern layer underlying the wiring pattern layer can be overcome without defects during transfer as described later.
To 60 μm. In addition, each wiring pattern layer 3,
The thickness of the conductive layers 3a, 4a, 5a forming the layers 4, 5 is
In order to keep the electric resistance of the wiring pattern layer low, the thickness is made 1 μm or more, preferably 5 to 40 μm. Further, the thickness of the insulating resin layers 3b, 4b, 5b depends on the electron beam curing type insulating resin to be used, but at least 1 μm or more, preferably 5 μm or more in order to maintain insulation between the upper and lower wiring pattern layers at the intersection. The range is up to 30 μm. The line width of such wiring pattern layers 3, 4, 5 can be arbitrarily set up to a minimum width of about 10 μm.

The material of the conductive layers 3a, 4a and 5a is not particularly limited as long as it can form a thin film by a plating method as described later, and for example, copper, silver, gold, nickel, chromium, zinc, Tin, platinum or the like can be used.

Further, the insulating resin for forming the insulating resin layers 3b, 4b, 5b exhibits adhesiveness or adhesiveness at room temperature or heating, and is electrodeposition method, coating filling method using squeegee, dispensing coating method. There is no particular limitation as long as it is an electron beam curable insulating resin capable of forming a film by a known means such as a screen printing method.

As such an electron beam curing type insulating resin, a resin or an oligomer having a polymerizable unsaturated bond, or a synthetic polymer such as a phenol resin, an epoxy resin or a polyimide is provided with a polymerizable unsaturated bond. The thing which added the oligomer which has it, etc. can be used. For example, when using an electrodepositable adhesive material that exhibits tackiness or adhesiveness at room temperature or heating, a polymerizable unsaturated bond (for example, anionic or cationic insulating synthetic polymer resin having tackiness) , Acrylic group, vinyl group,
The thing which added the oligomer which has an allyl group etc. can be used.

Specifically, as the anionic synthetic polymer resin, acrylic resin, polyester resin, maleated oil resin, polybutadiene resin, epoxy resin or the like may be used alone.
Alternatively, they can be used as a mixture of any combination of these resins. Further, the above-mentioned anionic synthetic polymer resin may be used in combination with a crosslinkable resin such as melamine resin, phenol resin and urethane resin.

Further, as the cationic synthetic polymer resin,
Acrylic resin, epoxy resin, urethane resin, polybutadiene resin, polyamide resin, polyimide resin and the like can be used alone or as a mixture of any combination thereof. Further, the above-mentioned cationic synthetic polymer resin may be used in combination with a crosslinkable resin such as polyester resin and urethane resin.

If desired, a tackifying resin such as a rosin-based resin, a terpene-based resin, or a petroleum resin-based resin may be added to impart tackiness to the polymer resin.

The above-mentioned polymer resin is subjected to the electrodeposition method in a state where it is solubilized in water by being neutralized with an alkaline or acidic substance or in a water-dispersed state in the production method of the present invention described later. That is, the anionic synthetic polymer resin is neutralized with amines such as trimethylamine, diethylamine, dimethylethanolamine and diisopropanolamine, and inorganic alkali such as ammonia and caustic potash. Also,
The cationic synthetic polymer resin is neutralized with an acid such as acetic acid, formic acid, propionic acid and lactic acid. Then, the polymer resin neutralized and solubilized in water is used in a state of being diluted with water as an aqueous dispersion type or a solution type.

Further, in order to cure such an electron beam curing type insulating resin to form the insulating resin layers 3b, 4b, 5b, at the time of transferring a wiring pattern layer described later, a Cockloft-Walton type, Bandegraph 1 to 500 keV, preferably 100 to 250 k, emitted from various electron beam accelerators such as type, resonance transformer type, insulating core transformer type, linear type, electro curtain type, dynamitron type, high frequency type, etc.
An electron beam having an energy of eV can be used.

Next, the manufacturing method of the multilayer printed wiring board according to the present invention will be described with reference to FIGS. 2 to 5 by taking the above-mentioned multilayer printed wiring board 1 as an example.

First, a photoresist is applied on a conductive substrate 11 as a transfer substrate to form a photoresist layer 12 (FIG. 2 (A)), and the photoresist layer 12 is exposed by contact using a predetermined photomask. Then, develop and conductive substrate 11
The wiring pattern portion 11a is exposed (see FIG. 2).
(B)). Next, the wiring pattern portion 1 of the conductive substrate 11
A conductive layer 14 is formed on 1a by a plating method (FIG. 2).
(C)). After that, the conductive layer 14 is formed by, for example, an electrodeposition method.
An electron beam curing type insulating resin layer 15 is formed on the upper surface (FIG.
(D)). Thus, the wiring pattern layer transfer plate 10 provided with the wiring pattern layer 13 for the first layer, which is a laminate of the conductive layer 14 and the electron beam curing type insulating resin layer 15, is obtained.

Similarly, as shown in FIGS. 3 and 4, conductive layers 24 and 34 are formed on the conductive substrates 21 and 31, respectively.
The wiring pattern layer transfer plate 20 for the second layer and the wiring pattern layer transfer plate 30 for the third layer provided with the wiring pattern layers 23, 33 having the electron beam curing type insulating resin layers 25, 35 are produced.

Next, the wiring pattern layer transfer plate 10 is pressure-bonded onto the substrate 2 so that the insulating resin layer 15 contacts the substrate 2. This pressure bonding may be performed by any method such as roller pressure bonding, plate pressure bonding, and vacuum pressure bonding. Further, when the insulating resin layer 15 exhibits tackiness or adhesiveness by heating, thermocompression bonding can be performed. In this state, the back surface of the substrate 2 (the surface on which the wiring pattern layer transfer plate 10 is not pressure bonded) is irradiated with an electron beam to insulate the insulating resin layer 15.
Is cured (aggregated) (FIG. 5 (A)). As a result, the adhesion between the substrate 2 and the insulating resin layer 15 becomes extremely high. Then, the conductive substrate 11 is peeled off and the wiring pattern layer 13 is transferred onto the substrate 2, whereby the first wiring pattern layer 3 which is a laminate of the conductive layer 3a and the insulating resin layer 3b is formed on the substrate 2. It is formed on top (FIG. 5 (B)).

Then, the wiring pattern layer transfer plate 20 for the second layer is used to align the first wiring pattern layer 3 on the substrate 2 on which the first wiring pattern layer 3 has been transferred. Then, the wiring pattern layer 23 is transferred in the same manner as the formation of the wiring pattern layer 3 of the first layer.
A second wiring pattern layer 4 which is a laminate of a and the insulating resin layer 4b is formed (FIG. 5C).

Further, on the substrate 2 on which the first wiring pattern layer 3 and the second wiring pattern layer 4 are formed, the wiring pattern layer transfer plate 30 for the third layer is used to be similarly positioned. Then, the wiring pattern layer 33 is transferred in the same manner as the formation of the first wiring pattern layer 3. As a result, the third wiring pattern layer 5 which is a laminated body of the conductive layer 5a and the insulating resin layer 5b is formed (FIG. 5).
(D)).

As described above, each wiring pattern layer 3, 4,
5 is performed by sequentially transferring the wiring pattern layers 13, 23 and 33 of the wiring pattern layer transfer plates 10, 20 and 30 onto the substrate, so that the multilayer printed wiring board 1 has the wiring pattern layers 3 and 4 respectively. , 5 is a so-called overprint type structure. Then, as shown in FIG. 6 which is a perspective view showing an intersection of the wiring pattern layer 3 and the wiring pattern layer 4 which form the multilayer printed wiring board 1, the conductive layers of the respective wiring pattern layers are partially always Will be bare,
At the intersections with the wiring pattern layers 3 and 4, the upper insulating resin layer 4b is used to form the conductive layers 3a and 4a of the wiring pattern layer.
The space is reliably insulated. In addition, each wiring pattern layer 3,
At the time of transferring 4,5, electron beams are irradiated to cure (aggregate) the electron beam curing type insulating resin, and the insulating resin layers 3b, 4b,
5b is formed, the substrate 2 and the insulating resin layers 3b, 4b,
5b adhesion, and therefore substrate 2 and wiring pattern layer 3,
The adhesiveness with 4, 5 is extremely high.

In the above-described method for manufacturing a multilayer printed wiring board, the insulating resin layer is cured (aggregated) by irradiating it with an electron beam from the back surface side of the substrate 2 (the surface on which the wiring pattern layer transfer plate is not pressure bonded). However, the present invention is not limited to this. That is, in the method for manufacturing a multilayer printed wiring board according to the present invention, the conductive substrate 11 forming the wiring pattern layer transfer plate is used.
When the total thickness of (21, 31) and the conductive layer 14 (24, 34) formed on the conductive substrate by plating is 1 mm or less, preferably 500 μm or less, the electron beam conducts. Since the electron beam curing type insulating resin layer can reach through the conductive substrate and the conductive layer, the insulating resin layer is cured (aggregated) by irradiating the electron beam from the conductive substrate surface side of the wiring pattern layer transfer plate. May be.

The multilayer printed wiring board 1 of the present invention is
An intersection or an overlapping portion as shown in FIG. 6, or a portion where each wiring pattern layer is close to each other as shown in FIG. 7 (a neighboring portion, in the illustrated example, the wiring pattern layer 3 and the wiring pattern layer 4 are (Close to each other), the wiring pattern layers can be easily connected to each other.

Next, the connection at the intersection or the proximity of each wiring pattern layer will be described by taking the multilayer printed wiring board 1 as an example.

8 to 12 show a multilayer printed wiring board 1
FIG. 6 is a perspective view showing a connection state of intersections of the wiring pattern layers of FIG. In FIG. 8, a joint portion 61 is formed and connected to the through hole formed in the upper wiring pattern layer 4. Further, in FIG. 9, a joint 62 is formed at a part of the intersection to connect the conductive layer 3a of the wiring pattern layer 3 and the conductive layer 4a of the wiring pattern layer 4. Further, in FIG. 10, a joint portion 63 is formed so as to cover the intersection of the wiring pattern layer 3 and the wiring pattern layer 4. Further, FIG. 11 shows the wiring pattern layer 3 and the wiring pattern layer 4 connected to each other by forming the bonding portion 64 so as to extend over a part of the proximity portion, and FIG. 12 shows the wiring pattern layer 3 and the wiring pattern. The joint portion 65 is formed and connected so as to cover the portion close to the layer 4.

As a connection by forming a junction at the intersection or the proximity of each wiring pattern layer,
(1) printing method, (2) dispensing method, (3) ultra fine particle spraying method, (4) laser drawing method, (5) selective electroless plating method,
(6) Selective vapor deposition method, (7) Welding joining method and the like.

The connection of the crossing portions or the proximity portions of the wiring pattern layers of the multilayer printed wiring board 1 by the printing method of the above (1) is so made as to extend between the conductive layers constituting each wiring pattern layer by printing. This is performed by fixing a conductive paste or solder to form a joint. The printing method used is not particularly limited, but screen printing, which is generally suitable for thick film printing and widely used in the electronic industry, is preferable. When performing screen printing, create a screen printing plate that has openings in the areas corresponding to the connections between wires in advance, place it in position on the multilayer wiring board, and place a conductive paste such as silver paste. Just print the ink.

Further, the connection at the intersection or the proximity of the wiring pattern layers of the multilayer printed wiring board 1 by the dispensing method of the above (2) is similar to the above-mentioned printing method, but the conductive ink is finely divided. This is performed by ejecting from a nozzle and directly drawing and forming a joint between wirings. Specifically, a dispenser having a needle-shaped ejection port, which is generally used for attaching a small amount of an adhesive or the like to a required place, can be used. Further, depending on the viscosity of the conductive ink used, an inkjet method used in an output device such as a computer can also be used.

In the ultrafine particle spraying method of the above (3), the ultrafine particles are carried by being carried on a high-speed air flow, and sprayed onto the multilayer printed wiring board from a fine nozzle provided close to the multilayer printed wiring board. A method of forming a film by sintering the ultrafine particles and the multilayer printed wiring board with each other by collision energy, and a method called a gas deposition method can be used. The apparatus used in this method is basically composed of two vacuum tanks of high vacuum and low vacuum, and a connecting pipe connecting each vacuum tank. The ultrafine particles are formed by a vacuum evaporation method in a low vacuum tank into which argon gas or the like is introduced, and the substrate is placed in a high vacuum tank. The connection pipe has an opening in the vicinity of the ultra-fine particles generated in the low vacuum tank and in the vicinity of the multilayer printed wiring board in the high vacuum tank and in a direction orthogonal to the wiring board. There is. Since each vacuum tank is kept at a constant pressure by the vacuum exhaust system, a high-speed air flow (gas flow) from the low vacuum tank to the high vacuum tank in the connecting pipe due to the pressure difference between the vacuum tanks. The ultrafine particles generated and generated in the low vacuum tank are carried on this air stream and conveyed to the high vacuum tank side, and collide with the wiring pattern layer of the multilayer printed wiring board to be sintered to form a film. By using this method with a metal such as gold, silver, copper or nickel as a base material, it is possible to selectively form a conductor (joint portion) at a place where a connection between wirings is required.

In the laser drawing method of the above (4), a solution in which conductive fine particles are dispersed is applied to a multilayer printed wiring board, and a desired portion of this coating film is heated by a laser to decompose or decompose the resin binder. It is vaporized and removed, and conductive fine particles are deposited and aggregated at the heated portions to selectively form a conductor. As the solution, a conductive resin fine particle such as gold or silver dispersed in a polyester resin, an acrylic resin, or the like is used, and a fine line of about several tens of μm can be drawn by irradiating with squeezing an argon laser or the like.

As the selective electroless plating method (5), a selective electroless plating technique generally known as a photoforming method can be used. This technique is capable of reducing and forming a photosensitizer layer containing a metal in an oxidized state serving as a catalyst for electroless plating on a multilayer printed wiring board, and selectively exposing the photosensitizer layer, In the electroless plating, metal particles serving as a catalyst are deposited and then immersed in an electroless plating solution to selectively plate only the exposed portion.

The selective vapor deposition method (6) uses a selective film deposition technique which is one of thin film forming techniques. That is, a metal, an organometallic gas containing a conductive element such as carbon, or an organic substance vapor containing a conductive element is introduced into the vacuum chamber, and the above gas or the above gas is applied to the surface of the multilayer printed wiring board installed in the vacuum chamber. The vapor is adsorbed, and then the laser or ion beam is condensed or converged to irradiate the substrate, and the gas or vapor adsorbed on the portion is decomposed by heat or collision energy to generate metal,
A conductive material such as carbon is deposited on the multilayer printed wiring board. Such a selective vapor deposition method has been put to practical use as a wiring correction technique for LSI. Specifically, with a focused argon laser, chromium, cobalt, platinum,
A technique for decomposing an organometallic gas containing tungsten and depositing these metals at a desired correction position, or a technique for decomposing a vapor of an organic material such as pyrene by an ion beam of gallium to deposit a carbon film is proposed. Can be used.

Further, in the welding joining method of the above (7), the crossing portion of the wiring pattern layers is selectively heated by a laser, and an insulating resin layer (upper layer is formed between the conductive layers of the upper and lower wiring pattern layers is formed. Insulating resin layer) is melted and evaporated, and
By heating the conductive layer itself to a high temperature, the conductive layers forming the respective wiring pattern layers are fused to each other to form a joint portion and connect them.

Further, the wiring pattern layers constituting the multilayer printed wiring board of the present invention are connected to each other by (8) wire bonding method and (9) wire bonding apparatus.
Shot method, (10) laser plating method, (11) batch transfer method of laminated body of conductor and solder plating, (12) metal lump insertion method, (13) electroless plating method and the like can be performed.
The wire bonding method of (8) above is performed, for example, by using the method shown in FIG.
As shown in (4), the adjacent portions where the wiring pattern layers 3 and 4 are not electrically connected (the same can be dealt with at intersections).
Is wire-bonded using a wire-bonding device, and the conductive layers 3a and 4a are connected by a wire bridge 66.

The one-shot method using the wire bonding apparatus of the above (9) is, for example, as shown in FIG. 14, a non-conducting proximity portion of the wiring pattern layers 3 and 4 (a crossing portion can be similarly dealt with. Is bonded for one shot (one time) using a wire bonding device, and the conductive layers 3a and 4a are formed without a bridge.
And a bonding block (pad) 67 is used to connect them.

In the laser plating method of the above (10), for example, a predetermined spot diameter, power on the irradiation surface, etc. were adjusted in a state where the multilayer printed wiring board before the connecting operation was immersed in a palladium plating solution. This is a method of irradiating a laser (for example, an argon laser) at a proximity portion or a crossing portion to be conducted for a predetermined time, and depositing a Pd film at a predetermined thickness on the irradiation portion and connecting the same. It is preferable to irradiate the laser while circulating the palladium plating solution. Further, the plating liquid is removed by washing with water, and the plating liquid shown in FIG.
The conductive film 3a and 4a are connected by the plated film 68 deposited as shown in FIG.

The collective transfer method of the laminated body of the conductor and the solder plating of the above (11) is performed as shown in FIGS. 16 (A) and 16 (B). First, as shown in FIG. 16B, a laminated body 70 of a conductor layer 71 and a solder plating layer 72 is manufactured in the following procedure. That is, on the conductive substrate 75,
A conductive layer 71 is formed, for example, by electroplating on a transfer substrate that has been developed using a resist method to form a desired pattern (conductive pattern), and a predetermined solder plating bath composition is formed on the conductive layer. Solder plating is performed using an object to form the solder plating layer 72. The solder plating layer 72 can be similarly formed by solder printing, screen printing of solder paste, or dipping. The laminated body 70 laminated in this manner is collectively thermally transferred to the non-conducting proximity portions (which can also be dealt with at the intersection portion) of the wiring pattern layers 3 and 4 as shown in FIG. 16 (A). , The conductive layers 3a and 4a are connected. At this time, the thermal transfer temperature is a temperature at which the solder plating layer 72 can be melted and deformed from 200 to
It is performed in a temperature range of about 300 ° C.

The method (12) for inserting a metal lump is shown in FIG.
As shown in (A), for example, a diameter of 30 to 1 is set in the wiring gap in the non-conducting proximity portion of the wiring pattern layers 3 and 4.
A method of arranging a metal ball 81 of about 00 μm, and thereafter, as shown in FIG. 17B, pressure-bonding a sheet 82 coated with a pressure-sensitive adhesive to connect the conductive layers 3a and 4a. Is. Although the use of metal balls is a preferred mode of use, they are not spherical, so-called metal pieces (lumps).
It is also possible to use something like. Further, such a metal ball (lump) can also be used to further improve the reliability of the connection portion in the printing method and the dispensing method. That is, the above-mentioned printing or dispensing is performed after the metal balls are installed.

FIG. 18 shows the electroless plating method of (13) above.
A description will be given based on (A) to (F). First of all,
An electroless plating catalyst is applied to the entire surface of a multilayer printed wiring board having wiring pattern layers 3 and 4 as shown in FIG. 8A to form a catalyst layer 91 (FIG. 18B). Then, a photoresist is applied on this to form a resist layer 93.
After forming, the resist layer 93 is exposed to light and developed using a predetermined photomask to expose the portion H corresponding to the position of the wiring pattern to be connected (FIG. 18C).
Then, after activating the exposed portion H, electroless plating is performed to form a connecting portion 95 to connect the conductive layers 3a and 4a (FIG. 18D). Then, the remaining unnecessary resist and the catalyst layer are sequentially removed to leave only the connecting portion 95 (catalyst layer 91a) (FIGS. 18E and 18F).

The multilayer printed wiring board of the present invention has been described above.
By using the connection method such as (2) to (13), it is possible to connect between the wiring pattern layers at any place without being restricted by the place where the through hole is formed. The degree of freedom in changing the circuit design is greater than that of the conventional multilayer printed wiring board.

In the above example, the multilayer printed wiring board 1 has a three-layer structure, but in the method for manufacturing a multilayer printed wiring board of the present invention, a desired number of wiring pattern layers can be obtained by repeating the same layer transfer. It is possible to manufacture a multilayer printed wiring board provided with.

The multi-layer printed wiring board of the present invention having a two-layer structure has a problem in the conventional double-sided printed wiring board, that is, high density due to the precision of the drilling process for forming holes in the double-sided printed wiring board. Can solve the problem. As described above, this is because the conductive layer is exposed, and it is possible to easily connect the wiring pattern layers to each other at the intersections of the wiring pattern layers or the adjacent portions without forming a through hole. Because.

[0061]

Next, the present invention will be described in more detail with reference to examples. Example 1 (1) Formation of Conductive Layer in Wiring Pattern Layer Transfer Plate (Corresponding to FIG. 2C) As a conductive transfer substrate, the surface was polished to a thickness of 0.2 m.
m stainless steel plate is prepared, and commercially available photoresist (PMER P-AR9 manufactured by Tokyo Ohka Kogyo Co., Ltd.) is mounted on the stainless steel plate.
00) to a thickness of 8 μm and dried, contact exposure is performed using a photomask on which a wiring pattern is formed, followed by development, washing with water, drying, and thermal curing to provide a transfer substrate having an insulating pattern. (3 types) were produced.

Next, each of the above-mentioned three kinds of transfer substrates and the platinum electrode are made to face each other and immersed in a copper pyrophosphate plating bath (pH = 8, liquid temperature = 55 ° C.) having the following composition, and a DC power source is used. Platinum electrode is connected to the anode of the above, the above-mentioned transfer substrate is connected to the cathode, and current is supplied at a current density of 10 A / dm ² for 5 minutes, and the exposed portion (wiring pattern portion) of the transfer substrate not covered with the insulating pattern ), A copper plating film having a thickness of 10 μm was formed as a conductive layer. This conductive layer formation was performed on three types of transfer substrates.

(Composition of copper pyrophosphate plating bath) Copper pyrophosphate: 94 g / l Copper potassium pyrophosphate: 340 g / l Ammonia water: 3 g / l (2) Formation of insulating resin layer in wiring pattern layer transfer plate (Corresponding to FIG. 2 (D)) Each transfer substrate on which the conductive layer was formed in (1) above was placed in an electron beam curing type insulating adhesive electrodeposition solution (Elecoat UC (cation electrodeposition type) manufactured by Shimizu Co., Ltd.) Immerse in, connect the transfer substrate to the cathode of the DC power supply, connect the platinum electrode to the anode, and
Electrodeposition was carried out for 1 minute at a voltage of, and this was dried at 80 ° C. for 10 minutes to form an electron beam curing type insulating resin layer (thickness: about 10 μm) on the conductive layer. As a result, wiring pattern layer transfer plates A1, A2, A3 provided with a wiring pattern layer composed of a conductive layer and an electron beam curing type insulating resin layer were obtained. (3) Production of multilayer printed wiring board (corresponding to FIG. 5) The wiring pattern layer transfer plate A1 produced in the above (2) was pressure-bonded onto a polyimide film substrate having a thickness of 25 μm under the following conditions.

(Pressure bonding conditions) Pressure: 10 kgf / cm ² Temperature: 100 ° C. In this state, electron beam is irradiated from the back surface of the film substrate under the following conditions to form the wiring pattern layer transfer plate A1. The curable insulating resin layer was cured, then the transfer substrate of the wiring pattern layer transfer plate A1 was peeled off, and the wiring pattern layer, which was a laminate of the conductive layer and the insulating resin layer, was transferred to the film substrate.

(Electron beam irradiation conditions) Equipment: Curetron (E manufactured by Nisshin High Voltage Co., Ltd.)
BC-200-AA2) Irradiation dose: 5 Mrad Next, the wiring pattern layer transfer plate A2 prepared in (2) above was transferred onto the film substrate on which the first wiring pattern layer was formed. Pressure bonding under the same conditions as above so that the adhesive layer contacts the first wiring pattern layer,
The electron beam curing type insulating resin layer was cured by electron beam irradiation, and the second wiring pattern layer was transferred.

Similarly, the wiring pattern layer transfer plate A3 produced in the above (2) is applied to the first wiring pattern layer and the second wiring pattern layer on the film substrate on which the second wiring pattern layer is formed. The third wiring pattern layer is transferred by pressure-bonding under the same conditions as above so that the adhesive layer comes into contact with the wiring pattern layer of the third layer, and curing the insulating resin layer of the electron beam curing type by electron beam irradiation. did.

As a result, a multilayer printed wiring board of the present invention having three wiring pattern layers as shown in FIG. 1 was produced. (Example 2) As an electron beam curing type insulating adhesive electrodeposition liquid,
Anion electrodeposition type electrodeposition solution (Elecoat UA manufactured by Shimizu Co., Ltd.) was used, and the transfer substrate was connected to the anode of the DC power source.
A multilayer of the present invention provided with three wiring pattern layers as shown in FIG. 1 in the same manner as in Example 1 except that a platinum electrode was connected to the cathode and electrodeposition was performed at a voltage of 50 V for 1 minute. A printed wiring board was produced.

[0068]

As described in detail above, according to the present invention, a wiring pattern layer transfer plate having a wiring pattern layer having an electron beam curing type insulating resin layer on a conductive layer is used to form a wiring pattern layer. Since the insulating resin layer is transferred (transferred) onto the substrate and the insulating resin layer is cured (aggregated) by electron beam irradiation during this transfer, the adhesion between the substrate and the insulating resin layer becomes extremely high. It is possible to form multiple layers of wiring pattern layers including a layer and an insulating resin layer. In this multi-layer formation, a plurality of wiring pattern layer transfer plates are produced in parallel, and these transfer pattern layer transfer plates are used to transfer sequentially. Since it is a parallel serial process, defective products can be eliminated by inspection before transfer, the manufacturing yield is improved, the throughput is high, and the wiring layer formation that was performed on the conventional substrate is performed. Plating for patterning, and photolithography process is unnecessary, thereby simplifying the manufacturing process.

The multilayer printed wiring board of the present invention also comprises
Since the wiring pattern is not covered by the insulating resin layer as seen in conventional multilayer printed wiring boards, the conductive layers that make up each wiring pattern layer are always partially exposed, and the wiring pattern layers intersect each other. It is a multi-layer printed wiring board with extremely high versatility that can easily connect the wiring pattern layers to each other in the overlapping portion, the overlapping portion, or the adjacent portion. The insulating resin layer ensures reliable insulation between the wiring pattern layers.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a multilayer printed wiring board according to the present invention.

FIG. 2 is a drawing for explaining the production of a wiring pattern layer transfer plate used in the method for producing a multilayer printed wiring board according to the present invention.

FIG. 3 is a schematic cross-sectional view showing an example of a wiring pattern layer transfer plate used in the method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of a wiring pattern layer transfer plate used in the method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 5 is a diagram illustrating a method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 6 is a perspective view showing an intersection of wiring pattern layers of the multilayer printed wiring board according to the present invention.

FIG. 7 is a perspective view showing the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

FIG. 8 is a perspective view showing a connection state at an intersection of wiring pattern layers of the multilayer printed wiring board according to the present invention.

FIG. 9 is a perspective view showing a connection state at an intersection of wiring pattern layers of the multilayer printed wiring board according to the present invention.

FIG. 10 is a perspective view showing a connection state at an intersection of wiring pattern layers of the multilayer printed wiring board according to the present invention.

FIG. 11 is a perspective view showing a connection state in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

FIG. 12 is a perspective view showing a connection state in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

FIG. 13 is a perspective view showing a connection state in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

FIG. 14 is a perspective view showing a connection state in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

FIG. 15 is a perspective view showing a connection state in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

FIG. 16 is a perspective view showing a state in which a joint portion in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention is sequentially formed.

FIG. 17 is a perspective view showing a state in which a joint portion in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention is sequentially formed.

FIG. 18 is a diagram for explaining formation of a joint portion in the vicinity of the wiring pattern layer of the multilayer printed wiring board according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Multilayer printed wiring board 2 ... Substrate 3,4,5 5 ... Wiring pattern layer 3a, 4a, 5a ... Conductive layer 3b, 4b, 5b ... Insulating resin layer 10, 20, 30 ... Wiring pattern layer transfer plate 11, 21 , 31 ... Transfer substrate 14, 24, 34 ... Conductive layer 15, 25, 35 ... Insulating resin layer 61, 62, 63, 64, 65, 66, 67, 68, 7
0, 81, 91 ... Joint

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H05K 3/20 6921-4E H05K 3/20 B 3/40 6921-4E 3/40 A

Claims (5)

[Claims] 1. A substrate, a plurality of wiring pattern layers sequentially transferred onto the substrate, the wiring pattern layer having a conductive layer and an insulating resin layer formed under the conductive layer, The insulating resin layer is a cured product of an electron beam curing type insulating resin, which is a multilayer printed wiring board. 2. The wiring pattern layer has a portion where the wiring pattern layers intersect and / or a portion where the wiring pattern layers are close to each other, and the insulation between the upper and lower wiring pattern layers is maintained by an insulating resin layer which constitutes an upper wiring pattern layer at the intersecting portions. The multilayer printed wiring board according to claim 1, wherein the multilayer printed wiring board is dripping. 3. The bonding portion according to claim 2, wherein a bonding portion is provided so as to straddle between the conductive layers forming the wiring pattern layer at necessary portions of the intersecting portion and / or the adjacent portion. Multilayer printed wiring board. 4. A pattern made of an insulating material is formed on a transfer substrate having at least a conductive surface, and a conductive layer can be peeled off by a plating method on a wiring pattern portion on the transfer substrate where the pattern is not formed. A plurality of wiring pattern layer transfer plates are produced by forming an electron beam curing type insulating resin layer on the conductive layer, and then the wiring pattern is formed on one surface of a substrate for a multilayer printed wiring board. An operation of pressing the layer transfer plate, irradiating an electron beam from the back side of the substrate to cure the insulating resin layer, and then peeling the transfer substrate to transfer the wiring pattern layer onto the substrate. A method for manufacturing a multilayer printed wiring board, characterized in that a plurality of the wiring pattern layers are formed on the substrate by repeating the sequence. 5. Forming a bonding portion so as to extend between the conductive layers forming each wiring pattern layer at a necessary portion of a portion where the wiring pattern layers intersect with each other and / or a portion where the wiring pattern layers are close to each other. The method for manufacturing a multilayer printed wiring board according to claim 4, wherein the wiring pattern layers are connected to each other by.