JPH1051141A - Multilayer printed wiring board and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a multilayer printed wiring board having reliable insulation at a portion where wiring pattern layers overlap with each other and having extremely excellent reliability, and a method of manufacturing the same. To provide. The substrate includes a substrate, and a plurality of wiring pattern layers sequentially transferred onto the substrate. The wiring pattern layer has a conductive layer and an insulating adhesive layer formed thereunder. A multilayer printed wiring board and a method of manufacturing the same, wherein an insulating layer made of a cured resin is formed between upper and lower wiring pattern layers at a portion which crosses or overlaps in a multilayer.

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 wiring board and a method for manufacturing the same, which can manufacture a multilayer printed wiring board having a high-definition pattern at low cost.

[0002]

2. Description of the Related Art Due to the rapid development of semiconductor technology, semiconductor packages have been reduced in size, the number of pins has been increased, the fine pitch has been increased.
The miniaturization of electronic components has rapidly progressed, and the era of so-called high-density mounting has entered. Along with this, printed wiring boards have been 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.

[0004] The subtractive method is a method in which a hole is formed in a copper-clad laminate, and then the inside and the surface of the hole are plated with copper, 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 in a portion other than a circuit pattern forming portion on a laminate containing an electroless plating catalyst, and a circuit is formed on an exposed portion of the laminate 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 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 a glass cloth with an epoxy resin or the like is used. Used. in this case,
The prepreg serves as an adhesive for each layer, and a connection between the layers is made by forming a through-hole and applying an electroless plating or the like to the inside.

Further, with the progress of high-density mounting, a multilayer substrate is required to be thin and light, and on the other hand, a high wiring capacity per unit area is required.
The connection between layers, the mounting method of components, and the like are devised.

However, the production of a multilayer substrate using the double-sided printed wiring board manufactured by the above-described subtractive method requires high precision in drilling for forming holes in the double-sided printed wiring board and the limit of miniaturization. There is a limit in increasing the density, and it has been difficult to reduce the manufacturing cost.

On the other hand, in recent years, a multilayer wiring board manufactured by sequentially laminating a conductor pattern layer and an insulating layer on a base material has been developed to satisfy the above-mentioned requirements. 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 an arbitrary position 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 connection between the layers is made by forming via holes, a complicated photolithography step is required, which hinders a reduction in manufacturing cost.

In order to solve such a problem, the present applicant has already provided a substrate and a plurality of wiring pattern layers sequentially transferred onto the substrate, wherein the wiring pattern layer is a conductive layer and the conductive layer. A multilayer printed wiring board having an insulating resin layer formed below the substrate and being fixed to the substrate or the lower wiring pattern layer by the insulating resin layer, and a method of manufacturing the same. 6-22
0962).

[0013]

However, in this proposal, it cannot be said that sufficient consideration is taken from the viewpoint of ensuring insulation at a portion where the wiring pattern layers overlap, and further improvement is required from the viewpoint of improving reliability. is necessary.
Also, in the proposed multilayer printed wiring board, each wiring pattern layer is not covered with an insulating layer except for the portion where the wiring pattern layer overlaps, and the leakage current from the side of the wiring pattern layer and the multilayer printed wiring board Insulation becomes unstable due to entrapment of air bubbles when coating (sealing) with epoxy resin or the like, or the conductive layer is easily oxidized, and this point needs to be improved. The present invention has been made under such circumstances, the object of the present invention is to
It is an object of the present invention to provide a multilayer printed wiring board in which insulation at a portion where wiring pattern layers overlap with each other and which is extremely excellent in reliability and a method for manufacturing the same.

[0014]

The above object of the present invention is achieved by the following present invention. That is, the present invention includes a substrate, a plurality of wiring pattern layers sequentially transferred on the substrate, the wiring pattern layer has a conductive layer and an insulating adhesive layer formed thereunder, and the wiring pattern layer has A multilayer printed wiring board characterized in that an insulating layer made of a cured resin is formed between upper and lower wiring pattern layers at portions where they cross each other or overlap in multiple layers.

Further, according to the present invention, a plurality of transfer masters having a wiring pattern layer having a conductive layer and an adhesive or adhesive insulating resin layer laminated thereon on a conductive substrate are prepared. Then, the operation of transferring the wiring pattern layer by sequentially pressing the transfer master on one surface of a substrate for a multilayer printed wiring board and peeling the transfer master is repeated on the substrate for the wiring board. A method for manufacturing a multilayer printed wiring board, comprising laminating a plurality of said wiring pattern layers, wherein before the wiring pattern layers are laminated, the cured resin is placed on the transferred wiring pattern layer where the wiring pattern layers are expected to overlap. A method for manufacturing a multilayer printed wiring board, comprising: forming an insulating layer made of the following; and performing the transfer operation thereafter.

[0016]

In particular, since an insulating layer made of a cured resin is separately formed on the conductive layer of the wiring pattern layer where the wiring pattern layers overlap, insulation at the place where the wiring pattern layers overlap is assured. Insulation instability is also eliminated by forming the insulating layer such that the wiring pattern layer at the location is covered with the insulating layer,
A multilayer printed wiring board with excellent reliability can be provided. Further, by using the multilayer printed wiring board of the present invention, a device that can withstand high voltage can be manufactured.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described in more detail by way of preferred embodiments. Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view of a three-layer printed wiring board showing an example of a multilayer printed wiring board obtained by the method of the present invention. In FIG. 1, a multilayer printed wiring board 1
A substrate 2, a first wiring pattern layer 3 provided on the substrate 2, a second wiring pattern layer 4 laminated on the wiring pattern layer 3, and a wiring pattern layer 4 3 having a third wiring pattern layer 5 laminated thereon
It is a multilayer printed wiring board having a layer configuration.

As shown in FIG. 1, when the first wiring pattern layer 3 and the second wiring pattern layer 4 laminated on the first wiring pattern layer 3 overlap, Is formed. Further, the second wiring pattern layer 4 and the third
The insulating layer 6 'is formed in a portion where the wiring pattern layer 5 of the layer overlaps. Each of these insulating layers is formed so as to cover the wiring pattern layer at the location.

It should be noted that a case where the first wiring pattern layer 3 and the third wiring pattern layer 5 may overlap with each other can be naturally assumed. It is formed.

Each of the wiring pattern layers 3, 4 and 5 constituting the multilayer printed wiring board 1 has conductive layers 3a and 4 respectively.
a, 5a and insulating adhesive layers 3b, 4b, 5b formed below the conductive layer. The multilayer printed wiring board 1 has an overprinted structure in which the wiring pattern layers 3, 4, and 5 are sequentially transferred and laminated on the substrate 2 or the lower wiring pattern layer. As described above, the insulating layers 6, 6
6 'is formed, and insulation between the upper and lower wiring pattern layers can be achieved by the insulating adhesive layer constituting the upper wiring pattern layer. However, in the present invention, a new cured resin is separately provided. Insulating layers 6 and 6 'made of, and as shown, the insulating layer is formed at a portion where the wiring pattern layer overlaps and is formed to cover the layer, so that the reliability of the multilayer printed wiring board is improved. It is improving. FIG. 5 is a perspective view showing a state in which the insulating layer 6 is formed at a position where the first wiring pattern layer 3 and the second wiring pattern layer 4 overlap with each other.

As described above, the multilayer printed wiring board 1 of the present invention has a structure in which the insulating layer is positively provided at places (intersections) where the respective wiring pattern layers overlap with each other. In FIG. 2, the conductive layers 3a, 4a, and 5a of the wiring pattern layers 3, 4, and 5 are partially exposed, and each wiring is formed at an intersection of the wiring pattern layers or at a portion where each wiring pattern layer is close to each other (proximal portion). The connection between the pattern layers can be easily performed.

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. The thickness of the substrate 2 is 5 to 1
It is preferably in the range of 000 μm. When a conductive substrate is used, an insulating layer is formed on one surface before use. At this time, as shown in FIG. 4D, by forming the wiring pattern layer larger than the size of the wiring pattern layer formed on the substrate, the alignment at the time of transfer can be given a margin (accurately). In addition, the insulation property can be further ensured.

The thickness of each of the wiring pattern layers 3, 4, and 5 is set to 100 μm or less, preferably 10 to 60 μm, so that the lower wiring pattern layer can be passed over without any defect in the lamination transfer described later. The thickness of the conductive layers 3a, 4a, 5a constituting each of the wiring pattern layers 3, 4, 5 is 1 μm in order to keep the electric resistance of the wiring pattern layers low.
As described above, the thickness is preferably in the range of 5 to 40 μm. further,
The thickness of the insulating adhesive layers 3b, 4b, 5b is 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, although it depends on the insulating adhesive or adhesive resin used. 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 a thin film can be formed by plating, as described later. For example, copper, silver, gold, nickel, chromium, zinc, tin, and tin , Platinum or the like can be used.

The material of the insulating adhesive layers 3b, 4b, 5b may be an electrodepositable insulating material exhibiting tackiness or adhesiveness at room temperature or by heating, as long as it forms a thin film by electrodeposition. Examples of such an electrodepositable insulating material include, for example, an anionic or cationic synthetic polymer resin which exhibits tackiness or adhesiveness at normal temperature or when heated.

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

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 cationic synthetic polymer resin may be used in combination with a crosslinkable resin such as a polyester resin and a urethane resin. It is also possible to add a rosin-based, terpene-based, petroleum resin-based tackifier resin or the like as needed to impart tackiness to the ionic polymer resin.

The ionic polymer resin is neutralized with an alkaline or acidic substance and solubilized in water in order to form an insulating film by electrodeposition as described below.
Alternatively, it is contained in the electrodeposition liquid in a water-dispersed state. That is,
The anionic synthetic polymer resin is neutralized with amines such as trimethylamine, diethylamine, dimethylethanolamine and diisopropanolamine, and with inorganic alkalis such as ammonia and potassium hydroxide. Further, the cationic synthetic polymer resin is neutralized with an acid such as acetic acid, formic acid, propionic acid, lactic acid and the like. 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.

In order to enhance the reliability of the ionic polymer resin exhibiting tackiness or adhesiveness, such as insulation and heat resistance, the polymer resin may be heat-polymerizable unsaturated such as blocked isocyanate. A known thermosetting resin having a bond may be added, and all the layers of the multilayer printed wiring board may be transferred and formed, and then all the insulating adhesive layers may be cured by heat treatment. Of course, if a resin having a polymerizable unsaturated bond (for example, an acrylic group, a vinyl group, an allyl group, etc.) is added to the ionic polymer resin in addition to the thermosetting resin, the entirety of the multilayer printed wiring board can be improved. After the transfer of the layers, all the insulating adhesive layers can be cured by electron beam irradiation.

Other materials for forming the insulating adhesive layers 3b, 4b, 5b include not only thermoplastic resins but also thermosetting resins as long as they exhibit tackiness at room temperature or by heating. An adhesive resin that loses adhesiveness may be used. Further, those containing an organic or inorganic filler for increasing the strength of the coating film may be used. Also, the insulating resin layer 3
The materials b, 4b and 5b may be electrodepositable adhesives which exhibit fluidity at room temperature or when heated.

As shown in FIG. 1, the insulating layers 6, 6 'made of a cured resin provided at the portions where the wiring pattern layers overlap each other completely cover the entire upper surface and side surfaces of the wiring pattern layers at the overlapping portions. Such a form is desirable in order to completely secure insulation. The material and forming method of such an insulating layer will be described later.

Next, referring to FIGS. 2 and 3, a three-layer multilayer printed wiring board, which is an example of the multilayer printed wiring board of the present invention shown in FIG. 1, will be described. The manufacturing method will be described. First, in order to prepare a transfer master used in the present invention, a photoresist is applied on a conductive substrate 11 as a transfer substrate to form a photoresist layer 12 (FIG. 2A). Then, the photoresist layer 12 is contact-exposed and developed using a predetermined photomask and developed to form an insulating layer 12 '(necessary when forming a wiring pattern layer on a transfer master, which is not itself transferred). Then, the wiring pattern portion 11a is exposed on the conductive substrate 11 (FIG. 2 (2)).

Next, a conductive layer 3a is formed on the wiring pattern portion 11a of the conductive substrate 11 by plating (FIG. 2 (3)). Thereafter, an adhesive or adhesive insulating adhesive layer 3b is formed on the conductive layer 3a by an electrodeposition method (FIG. 2 (4)). As a result, a transfer master 10 for forming a wiring pattern layer provided with the first wiring pattern layer 3 having the conductive layer 3a and the insulating adhesive layer 3b is obtained.
The transfer original plate provided with the second and subsequent wiring pattern layers is manufactured in the same manner as described above.

Next, the transfer original plate 10 for forming a wiring pattern layer is pressed on the substrate 2 so that the insulating adhesive layer 3b contacts the substrate 2 (FIG. 2 (5)). This crimp is
Any method such as roller pressing, plate pressing, and vacuum pressing may be used. When the insulating adhesive layer is made of an insulating resin that exhibits tackiness or adhesiveness when heated, thermocompression bonding can be performed. Thereafter, the conductive substrate 11 is peeled off and the wiring pattern layer 3 is transferred onto the substrate 2 to thereby form the conductive layer 3 as shown in FIG.
a and a first wiring pattern layer 3 having an insulating adhesive layer 3b are formed on the substrate 2.

The portion on the first wiring pattern layer 3 thus formed, which is to be overlapped with the second wiring pattern layer 4 to be laminated in the next transfer, will be described by a method described below. The insulating layer 6 made of the cured resin shown in FIG. 3 (C) is formed so as to be larger than the wiring pattern layer in the portion and to cover the layer. The portion to be overlapped means a portion that inevitably overlaps when the wiring pattern layer to be laminated in the next step is transferred.

The insulating layer made of a cured resin is made of a photosensitive and patternable insulating resin (photosensitive insulating resin) or an etching and patternable curable insulating resin (etchable insulating resin). Resin). When the multilayer printed wiring board is a conductive board, an insulating layer provided between the board and the wiring pattern layer is similarly formed using the above resin. As the photosensitive insulating resin, for example, any of known positive and negative photoresists having insulating properties can be used. In addition, examples of the etching insulating resin include a polyimide resin and an epoxy resin.

When the insulating layer is formed using, for example, a photoresist as a photosensitive insulating resin, a layer made of a photoresist is formed on the conductive substrate so as to cover the transferred wiring pattern layer. A mask that has been patterned so that the insulating layer is formed on a portion of the wiring pattern layer that has been transferred onto the wiring pattern layer that is to be overlapped in the next transfer operation is formed, and normal exposure on photoresist is performed.
A developing operation is performed to remove the photoresist layer in other portions so that the photoresist layer is formed in portions where the overlap on the wiring pattern layer is expected. Thereafter, by curing the photoresist layer, an insulating layer made of a cured resin is formed (FIGS. 3B and 3C). Example 1 described below is this example.

After the insulating layer 6 made of the cured resin is formed by the above method (FIG. 3C), the second layer of the second layer is transferred onto the substrate 2 on which the first layer of the wiring pattern 3 has been transferred. Using the transfer master for the wiring pattern layer, the wiring pattern layer is transferred to the first wiring pattern layer in the same manner as above, and has a conductive layer 4a and an insulating adhesive layer 4b. A second wiring pattern layer 4 is formed (FIG. 3
(D)). In this manner, the insulating layer 6 is formed at the overlapping portion between the first wiring pattern layer 3 and the second wiring pattern layer 4.
Is formed.

Next, before transferring the third wiring pattern layer 5 onto the second wiring pattern layer 4, the second wiring pattern layer 4 and the third wiring pattern The insulating layer 6 'is formed in a portion where the layer 5 is to be overlapped by the above-mentioned method (FIG. 3E). In the embodiment shown in FIG. 1, it is assumed that only the second wiring pattern layer 4 overlaps with the first wiring pattern layer 3 for easy understanding (actually, Often overlaps with the third wiring pattern layer 5). In FIG. 1, it is assumed that only the third wiring pattern layer 5 overlaps with the second wiring pattern layer 4.

Lastly, the wiring pattern layer is transferred by performing positioning using the transfer master for forming the third wiring pattern layer on the stacked second wiring pattern layer 4 to transfer the wiring pattern layer. A third wiring pattern layer 5 having a conductive layer 5a and an insulating resin layer 5b is formed (FIG. 3F). In this case, the insulating layer 6 'is formed at the portion where the second wiring pattern layer 4 and the third wiring pattern layer 5 overlap. The example shown in FIG. This is an example in which the number of overlapping portions of the wiring pattern layers is reduced as much as possible in order to facilitate the above, and it goes without saying that the number is not limited to this number.

In the above-described example, the transfer master 10 for the wiring pattern layer and the like have a conductive layer directly on the substrate 11 and an adhesive or adhesive insulating adhesive layer formed thereon. However, with respect to the transfer original plate 10 for the first wiring pattern layer, an insulating resin layer made of a photoresist may be formed in advance. If the insulating resin layer is not formed beforehand, the first wiring pattern layer is transferred onto the substrate 2 by providing an insulating pressure-sensitive adhesive layer or an adhesive layer on the substrate 2 in advance. be able to.

Another method of forming an insulating layer made of a cured resin is as shown in FIGS. 4A to 4F (in this example, the substrate 2 of the multilayer printed wiring board is electrically conductive, and In this method, an insulating layer 7 made of a cured photosensitive resin is also formed (FIG. 4C). In this method, similarly to the case where a photosensitive resin is used, a film 6 is formed on a substrate so as to cover the transferred wiring pattern layer 3 (FIG. 4D), and the above-mentioned photoresist is formed thereon. The layer 8 is formed (FIG. 4E), a mask pattern is formed on the etchable insulating resin layer using a predetermined mask, and then a layer on which the insulating layer is to be formed is formed by etching (FIG. 4E). (F), the mask pattern is removed (see FIG. 3 (C)), and the remaining etchable insulating resin layer 6 is cured. Next, the second and subsequent wiring pattern layers are formed in the same manner as described above. This method has the advantages that the material cost is lower than the method using a photosensitive resin, and there is no need to select a positive type or a negative type. Example 2 described below is this example.

As described above, the insulating layer made of the cured resin is formed at the portion where the wiring patterns overlap each other,
Also, when the multilayer printed wiring board substrate is conductive,
Similarly, by providing the insulating layer between the substrate and the wiring pattern layer, the multilayer printed wiring board of the present invention in which the insulating property is ensured is manufactured.

[0045]

Next, the present invention will be described more specifically with reference to examples. In the following, parts and percentages are by weight unless otherwise specified. Example 1

(1) Formation of conductive layer on transfer master A stainless steel plate having a polished surface and a thickness of 0.2 mm was prepared as a conductive substrate, and a commercially available plating photoresist (Tokyo Ohka Chemical Co., Ltd.) was placed on the stainless steel plate. Industrial PMER P-AR9
00) is applied to a thickness of 10 μm and dried, and is subjected to contact exposure using a photomask on which a predetermined wiring pattern is formed, followed by development, washing and drying to form a photoresist layer having a predetermined wiring pattern. Thus, a transfer master for forming a first wiring pattern layer was obtained. Similarly, a transfer master for forming the second and third wiring pattern layers was prepared.

Each of the transfer masters and the oxygen-free copper electrode were opposed to each other, and a copper pyrophosphate plating bath having the following composition (pH = 8,
Solution temperature = 55 ° C.), a platinum electrode was connected to the anode of the DC power supply, and the above-mentioned transfer master was connected to the cathode, and the current density was 10 A /
A current of dm ² was applied for 5 minutes, and a 10 μm-thick copper plating film was formed on the bare portion of the conductive substrate that was not covered with the photoresist, thereby forming a conductive layer.

Composition of copper pyrophosphate plating bath Copper pyrophosphate 94 g / liter Potassium pyrophosphate 340 g / liter ammonia water 3 g / liter

(2) Formation of Insulating Adhesive Layer on Transfer Master The transfer master on which the conductive layer was formed and the platinum electrode were opposed to each other and immersed in the following electrodeposition solution for forming an insulating adhesive layer. The transfer master was connected to the cathode of the power supply, and the platinum electrode was connected to the cathode. Electrodeposition was performed at a voltage of 50 V for 1 minute, drying and heat treatment were performed at 150 ° C. for 30 minutes, and a thickness of 20 μm was formed on the conductive layer.
Was formed. Thus, three types of transfer masters A1, A2 and A3 were obtained.

Preparation of electrodeposition solution for forming insulating adhesive layer: 13.2 parts of butyl acrylate, 1.6 parts of methyl methacrylate,
0.2 parts of divinylbenzene and 85 parts of a 1% aqueous solution of potassium persulfate were mixed, and emulsion polymerization of an emulsifier was performed at 80 ° C. for 5 hours to prepare an emulsion of a butyl acrylate / poly (methyl methacrylate) copolymer. . Next, 65 parts of this emulsion, 2 parts of an acrylic copolymer resin having a carboxyl group as an electrodeposition carrier, 0.85 parts of hexamethoxymelanin, and 0.1% of trimethylamine as a neutralizing agent.
35 parts of ethanol, 3 parts of ethanol, 3 parts of butyl cellosolve and 18.8 parts of ion-exchanged water were mixed and stirred to prepare an electrodeposition solution for forming an anionic insulating adhesive layer.

(3) Fabrication of Multilayer Printed Wiring Board (Formation of Insulating Resin Layer on Conductive Substrate) Photosensitive insulating resin (RN-902, manufactured by Nissan Chemical Co., Ltd.) on a SUS304 thin plate having a thickness of 25 μm. The solution was spin-coated to 10
After applying to a thickness of μm and performing exposure and development, 170 ° C
Curing was performed for 60 minutes at 350 ° C. for 30 minutes to form an insulating thin film.

(Transfer of the First Wiring Pattern Layer) The conductive substrate and the transfer master A1 for the wiring pattern layer prepared in the above (2) are pressure-bonded at a pressure of 10 kgf / cm ² and 80 ° C. The first wiring pattern layer having a conductive layer and an insulating adhesive layer thereunder is transferred, and then the adhesive layer is cured at 180 ° C. for 30 minutes to form the first wiring pattern layer. Was completed.

(Formation of Insulating Layer Made of Cured Resin) Next, the above photosensitive insulating resin was applied to a thickness of 10 μm on the substrate on which the first wiring pattern layer was formed by spin coating. After performing exposure and development under the following conditions using a desired mask, curing was performed at 170 ° C. for 60 minutes and at 350 ° C. for 30 minutes to form an insulating layer made of a cured resin.

Contact exposure machine: manufactured by Dainippon Screen Mfg. Co., Ltd.
P-202-G Vacuum evacuation: 60 seconds Exposure time: 400 counts

(Transfer of Second Wiring Pattern Layer) Thereafter, the transfer master A2 for forming a wiring pattern layer prepared in the above (2) was applied onto the substrate on which the insulating layer was formed at a pressure of 10 kgf / cm ^{2 at} a temperature of 80 ° C.
The second wiring pattern layer was transferred, and then the adhesive layer was cured at 180 ° C. for 3 minutes to complete the formation of the second wiring pattern layer.

(Formation of Insulating Layer Made of Cured Resin and Third
Transfer of the wiring pattern layer of the layer)
After a thin film of the same photosensitive insulating resin as described above is formed and cured on the substrate on which the wiring pattern layer of the layer is formed under the same conditions, a transfer master for forming a wiring pattern layer prepared in (2) above A3 is pressed under the same conditions as the transfer master A2 to transfer the third wiring pattern layer including the conductive layer and the insulating adhesive layer, and then the adhesive layer is cured at 180 ° C. for 30 minutes. The formation of the third wiring pattern layer was completed.
By the above operation, a multilayer printed wiring board of the present invention in which three types of wiring pattern layers were laminated was obtained. This embodiment corresponds to the manufacturing process shown in FIG. 3, but is different from this embodiment in that the insulating resin layer is not formed in advance on the substrate for the multilayer printed wiring board in FIG.

Example 2 Using the transfer masters A1, A2 and A3 prepared in Example 1, a multilayer printed wiring board having three wiring pattern layers laminated was prepared by the following method. FIG. 4 shows a part of the manufacturing process.

Preparation of Multilayer Printed Wiring Board (Formation of Insulating Resin Layer on Conductive Substrate) A 25 μm-thick SUS304 thin plate is spin-coated with an etching-type insulating resin (SP-341 manufactured by Toray Industries, Inc.) solution. And dried at 95 ° C. for 1.5 minutes and then at 120 ° C. for 1.5 minutes on a hot plate to form an insulating resin thin film having a thickness of about 11 μm. Thereafter, a solution of a positive resist (OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied by the same spin coating method and dried (on a hot plate at 105 ° C. for 25 minutes) (FIG. 4A) under the following conditions. Exposure and development were performed using a desired mask to simultaneously pattern the positive resist layer and the insulating resin layer (FIG. 4B). Thereafter, the positive resist was peeled off with n-butyl acetate (FIG. 4C), and only the patterned insulating resin layer was cured (140 ° C. for 5 minutes in an oven, then 350 ° C. for 20 minutes). conditions).

Exposure conditions for positive resist: Contact filter: P-202- manufactured by Dainippon Screen Mfg. Co., Ltd.
G Vacuum: 60 seconds Exposure time: 30 counts

(Transfer of First Layer Wiring Pattern Layer) The transfer original plate A1 for forming a wiring pattern layer is pressure-bonded to the above-mentioned substrate under the conditions of a pressure of 10 kgf / cm ² and a temperature of 80 ° C. The first wiring pattern layer composed of the insulating adhesive layer was transferred, and then the adhesive was cured at 180 ° C. for 30 minutes to complete the formation of the first wiring pattern layer (FIG. 4D )).

(Formation of Insulating Layer Made of Cured Resin)
The above-mentioned insulating resin solution is applied to a thickness of 11 μm on the substrate on which the first wiring pattern layer is formed by spin coating, and a positive resist (OFPR- manufactured by Tokyo Ohka Kogyo Co., Ltd.) is further applied thereon. 800) Similarly, the solution is applied by a spin coating method, dried (on a hot plate at 105 ° C. for 2.5 minutes) (FIG. 4E), exposed and developed using a desired mask under the same conditions as described above, and subjected to positive The pattern resist and the insulating resin were simultaneously patterned (FIG. 4F). After that, the positive resist was peeled off with n-butyl acetate,
Only the insulating resin was cured (140 ° C, 5
Minutes, 200 ° C. for 30 minutes, and then 350 ° C. for 20 minutes) (see FIG. 3C).

(Transfer of the Second Layer Wiring Pattern Layer) The transfer original plate A2 for the wiring pattern layer is pressed on the above substrate under the following conditions to form a conductive layer of the second layer consisting of an adhesive layer. Was transferred, and then the adhesive layer was cured at 180 ° C. for 30 minutes to complete the formation of the second wiring pattern layer (see FIG. 3D).

(Formation of Insulating Layer Made of Cured Resin and Third
Similarly, the insulating layer is formed on the substrate on which the second-layer wiring pattern is formed in the same manner as described above, and the transfer master A3 for forming the wiring pattern layer is transferred. The third wiring pattern layer including the conductive layer and the adhesive layer was transferred by pressing under the same conditions as the pressing of the original A2, and then the adhesive layer was cured at 180 ° C. for 30 minutes. The formation of the third wiring pattern layer is completed (FIG.
(F)). As described above, a multilayer printed wiring board of the present invention including three wiring pattern layers was manufactured.

[0064]

As described above in detail, according to the present invention, the wiring pattern layer comprising the conductive layer and the insulating adhesive layer provided on the transfer master is transferred onto the substrate, whereby the conductive A wiring pattern layer having an insulating adhesive layer beneath a conductive layer can be laminated in multiple layers on a substrate. In this multilayer lamination, a plurality of transfer masters on which a predetermined wiring pattern layer is formed are produced in parallel. Because of the parallel-serial process in which these transfer originals are sequentially transferred, defective products can be eliminated by inspection before transfer, the production yield is improved, the throughput is high, and the conventional substrate The plating and photo-etching steps for forming and patterning the wiring layer, which were performed in the previous step, are no longer necessary, which simplifies the manufacturing process and reduces costs by reusing the transfer master substrate. It is. Also, in the multilayer printed wiring board, the conductive layer constituting each wiring pattern layer is always exposed at a portion necessary for connection between the wiring pattern layers, and the intersection of each wiring pattern layer is made of a cured resin. Insulation is ensured by the insulating layer. Further, it is possible to easily connect the respective wiring pattern layers to each other at a portion where the respective wiring pattern layers are close to each other, and it is possible to manufacture a multilayer printed wiring board having extremely high versatility. Further, by covering the wiring pattern layer in the above-mentioned portion of the wiring pattern layer with an insulating layer, the insulation is further ensured.

[Brief description of the drawings]

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

FIG. 2 is a drawing for explaining a method of manufacturing a transfer master according to the present invention.

FIG. 3 is a schematic diagram for explaining a method of manufacturing the multilayer printed wiring board shown in FIG.

FIG. 4 is a schematic diagram for explaining a method of manufacturing the multilayer printed wiring board shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer printed wiring board 2 ... Substrate 3,4,5 ... Wiring pattern layer 3a, 4a, 5a ... Conducting layer 3b, 4b, 5b ... Insulating adhesive layer 10 ... Transfer original plate 11 ... Conducting substrate 6,6 '... an insulating layer made of a curable resin 7 ... an etching insulating resin layer 8 ... a photosensitive insulating resin layer

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[Procedure amendment]

[Submission date] September 13, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

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

FIG. 2 is a drawing for explaining a method for producing a transfer master according to the present invention.

FIG. 3 is a schematic diagram for explaining a method of manufacturing the multilayer printed wiring board shown in FIG.

FIG. 4 is a schematic diagram for explaining a method of manufacturing the multilayer printed wiring board shown in FIG.

FIG. 5 is a schematic perspective view showing a state of formation of an insulating layer at a portion where wiring pattern layers of the multilayer printed wiring board shown in FIG. 1 overlap.

DESCRIPTION OF SYMBOLS 1 ... Multilayer printed wiring board 2 ... Substrate 3,4,5 ... Wiring pattern layer 3a, 4a, 5a ... Conductive layer 3b, 4b, 5b ... Insulating adhesive layer 10 ... Transfer original plate 11 ... Conductivity Substrates 6, 6 '... Insulating layer made of curable resin 7 ... Etching insulating resin layer 8 ... Photosensitive insulating resin layer

Claims (11)

[Claims] A substrate, a plurality of wiring pattern layers sequentially transferred onto the substrate, the wiring pattern layer having a conductive layer and an insulating adhesive layer formed thereunder; A multilayer printed wiring board, wherein an insulating layer made of a cured resin is formed between upper and lower wiring pattern layers at portions where they cross each other or overlap in multiple layers. 2. The multilayer printed wiring board according to claim 1, wherein the substrate is a conductive substrate, and the insulating layer is formed between the substrate and the wiring pattern layer. 3. The multilayer printed wiring board according to claim 1, wherein the insulating layer is larger than the wiring pattern layer. 4. The multilayer according to claim 1, wherein the insulating layer is formed by curing a layer made of an insulating resin having photosensitivity and capable of forming a pattern. Printed wiring board. 5. The multilayer printed wiring board according to claim 1, wherein the insulating layer is formed by curing an insulating resin having an etching property and capable of forming a pattern. 6. The wiring pattern layers are connected to each other at a necessary portion of a portion where the wiring pattern layers cross each other and / or a portion where the wiring pattern layers are close to each other. The multilayer printed wiring board according to any one of claims 1 to 5. 7. A plurality of transfer masters provided with a wiring pattern layer having a conductive layer and an insulating adhesive layer laminated thereon on a conductive substrate are produced, and then a transfer master for a multilayer printed wiring board is prepared. The operation of transferring the wiring pattern layer onto a substrate for a multilayer printed wiring board by sequentially pressing the transfer master on one surface of the substrate and peeling the transfer master is repeated to obtain a substrate for the multilayer printed wiring board. A method for manufacturing a multilayer printed wiring board, comprising laminating a plurality of said wiring pattern layers on the wiring pattern layers, wherein the wiring pattern layers are cured before being stacked on the transferred wiring pattern layers. A method for manufacturing a multilayer printed wiring board, comprising forming an insulating layer made of a resin, and thereafter performing the transfer operation. 8. The multilayer printed circuit according to claim 7, wherein the substrate of the multilayer printed wiring board is a conductive substrate, and the insulating layer is formed between the substrate and the wiring pattern layer to be larger than the size of the wiring pattern layer. Manufacturing method of wiring board. 9. The method for manufacturing a multilayer printed wiring board according to claim 7, wherein the insulating layer made of the cured resin is formed of a photosensitive insulating resin or an insulating resin having an etching property. 10. An insulating layer made of a cured resin is formed by forming a layer made of a photosensitive insulating resin on the substrate so as to cover the transferred wiring pattern layer, and exposing and developing the layer with a predetermined mask. 10. The composition is formed by curing after forming.
3. The method for producing a multilayer printed wiring board according to item 1. 11. An insulating layer made of a cured resin, a layer made of an insulating resin having an etching property is formed on the substrate so as to cover the transferred wiring pattern layer, and then a layer of a photosensitive resin is formed thereon. 10. The method according to claim 9, wherein after forming a predetermined mask pattern, the layer made of the insulating resin is etched, and after removing the mask pattern, the etched layer made of the insulating resin is cured and formed. Of manufacturing a multilayer printed wiring board.