JPH08195560A - Method for manufacturing printed circuit board - Google Patents

Abstract

PURPOSE: To achieve contact and contact bonding to an opposing conductor circuit layer by allowing a protrusion to break through an insulator resin layer with the pressure obtained by pressing a lamination body using a press tool plate. CONSTITUTION: A protrusion 112 for connecting first and second conductor layers, a protrusion 122 for connecting second and third conductor layers, and a protrusion 132 for connecting third and fourth conductor layers break through an insulator 120 between the first and second conductor layers, an insulator 130 between the second and third conductor layers, and an insulator 140 between the third and fourth conductor layers, thus achieving contact to a second conductor layer 121, a third conductor layer 131, and a fourth conductor layer 141, respectively, for improved contact bonding. The insulator layer between conductor layers is a sheet made of insulation resin and the protrusion for connecting conductor layers is formed by electrolytic plating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed circuit board, and more particularly to a method for manufacturing a printed circuit board called a multilayer printed circuit board having a large number of conductor wiring layers in the thickness direction of one board. It is a thing.

[0002]

2. Description of the Related Art Regarding a printed circuit board of this type,
For example, literature; printed circuit board technology and its quality assurance: published by Applied Technology Publishing Co., Ltd., Information Technology Center, (Showa 55
(Published August 27, 2013).

[0003] Conventionally, in the manufacture of printed circuit boards, a copper clad laminate in which a sheet-like plate made by weaving glass fibers into a cloth shape is impregnated with an insulating resin and a copper foil is attached to one or both sides of the sheet. Alternatively, use a copper foil prepreg made by pasting a copper foil on a sheet-shaped insulating material that is a sheet-shaped plate woven of glass fiber in a cloth shape and impregnated with an insulating resin. A method of forming a necessary circuit by a technique such as the above has been adopted.

Further, in the case of manufacturing the above-mentioned multi-layer board having a large number of copper layers in addition to the above-mentioned single-layer board,
Electrical circuit connections between copper circuit layers are required. For such connection between layers, a through hole penetrating in the thickness direction is formed, the inner wall of the through hole is coated with a conductive film by a method such as plating, and the layer is electrically connected to a layer requiring connection. It has a structure. Therefore, it is necessary to make a hole in the substrate with a drill or the like in order to provide a through hole at a required place. Then, a method in which materials for which circuit formation is completed by these methods are stacked and pressed by heat and pressure to manufacture a multilayer substrate has been mainstream.

[0005]

In the conventional method of manufacturing a printed circuit board as described above, the size of the board is made smaller and thinner, the thickness of the interlayer is made thinner, and the through-hole is further required, as required by the latest technology. When the hole diameter was also very small, there were some problems as listed below. (1) The glass fiber forming the copper clad laminate or the prepreg becomes an obstacle to the drilling process for drilling through holes. (2) Since glass fiber damages the blade of the drill, the life of the blade of the drill is significantly shortened, and especially when the hole diameter is small, the cost of the blade edge of the drill is increased due to breakage of the drill. (3) With methods such as drilling and laser processing, there is a limit to the hole diameter that can be processed. (4) If the diameter of the through hole is reduced in the plating in the small diameter through hole and its pretreatment process, the plating solution or the processing solution does not enter the hole, so that the plating is not formed, resulting in poor conduction. Due to these problems, it is difficult to manufacture the printed circuit board, the probability of occurrence of defects increases, and further progresses, there is a problem that the manufacturing method becomes difficult.

[0006]

A method for manufacturing a printed circuit board according to the present invention comprises stacking a predetermined number of insulator layers having conductor circuit layers on both sides or one side and insulator layers having no conductor circuit layers. The laminated body is pressed and molded from both end faces using a press jig plate having a conductor circuit layer, and at the same time, at least two conductor circuit layers at a predetermined level are electrically connected to form a multilayer printed circuit board. In the method for manufacturing a printed circuit board, the insulating layer is formed of a sheet-shaped insulating resin layer that does not contain any glass fiber, and for electrical connection between the conductive circuit layers on a predetermined place of the conductive circuit layer. A protrusion made of a conductor is provided, and the protrusion breaks through the insulating resin layer due to the pressure generated by pressing the laminated body using a pressing jig plate, and the conductor resin layer is brought into contact with and pressure-bonded to the opposing conductor circuit layer. is there.

Further, in the above-mentioned means for the protrusion to break through the insulating resin layer, a manufacturing method for heating the insulating resin layer to the melting temperature of the insulating resin layer to facilitate the breaking of the protrusion may be applied. Separately, instead of a means for the protrusion to break through the insulating resin layer, a hole large enough for the protrusion to pass is formed in advance at the position where the protrusion penetrates, and the conductor circuit layer facing the conductor circuit layer through the hole during pressing. You may make it contact | abut and crimp. Furthermore, a solder layer having a melting temperature higher than the resin curing temperature of the insulating resin layer is provided at the tip of the protrusion, and the insulating resin layer is pierced by the protrusion by heat and pressure and the solder layer is pressed against the conductor circuit layer. Then, after curing the insulating resin layer, the temperature is raised to the melting temperature of the solder in this state to melt the solder layer and connect the protrusion to the conductor circuit layer, and then cooled to solidify the solder layer. A manufacturing method may be used. In addition, the protrusions formed on the conductor circuit layer that constitutes the connecting portion are provided at the same positions of the upper and lower insulating resin layers so that the tips of the protrusions face each other, and the connecting portions contact the tips of the protrusions during pressing. You may use the thing of a protrusion part structure provided with the surface which slides, and the surface which meshes mutually and is caught and contacted.

[0008]

According to the present invention, a laminate in which a predetermined number of insulator layers having conductor circuit layers on both sides or one side and insulator layers having no conductor circuit layers are stacked is pressed and molded at the same time. In the method for manufacturing a printed circuit board in which at least two upper and lower conductor circuit layers are electrically connected, the insulator layer is formed of a sheet-shaped insulator resin layer containing neither glass fiber, A protrusion (metal block) made of a conductor for electrical connection between conductor circuit layers is provided on a predetermined place, and the laminated body is pressed using a pressing jig plate. Therefore, compared to the conventional sheet-shaped insulating resin material (prepreg) containing fibers, the insulating resin layer can be pierced by the projection of the insulating resin layer due to the pressing pressure. Since the protrusion is brought into contact with and pressure-bonded to the conductor circuit layer, the connecting portion can be formed thinner and with a smaller diameter (small area) than the conventional forming of the connecting portion by the through hole.

[0009]

Embodiments (First Embodiment) FIG. 1 is a substrate configuration explanatory view showing a first embodiment of the present invention. A left side view (a) is a state before press molding, and a right side view (b) is a press. The state after molding is shown.
110 is a first conductor layer 11 that constitutes a circuit pattern.
1 is a plate-shaped lower stainless steel table for forming 1 and has a conductive metal such as stainless steel (hereinafter referred to as stainless steel) whose surface is mirror-finished so that the resin and the copper material are easily separated in the final step. Is made of. The lower stainless steel table 110 not only serves as a table for forming the first conductor layer 111, but also serves as a pressing plate of a lower pressing jig during hot pressing, and has a thickness of at least 1 mm. It is necessary, and it is necessary that the surface without warpage is smooth. Then, the first conductor layer 111 to be a circuit pattern is formed on the smooth surface of the lower stainless steel table 110. The formation may be performed by electrolytic plating using a plating resist. For example, a screen plate using a paste or the like may be used. It is also possible to use a printing method such as printing.

Protrusions 112 for connecting the first and second conductor layers are formed on predetermined locations of the formed first conductor layer 111. The formation of the first and second conductor interlayer connection protrusions 112 is
Although it may be performed after forming the first conductor layer 111, it may be performed at the same time when the first conductor layer 111 is formed. The method for forming the first and second conductor interlayer connecting protrusions 112 is as follows.
Similar to the method of forming the first conductor layer 111, the first conductor layer 111 may be formed by an electrolytic plating method using a plating resist, a screen printing method using a conductive paste or the like, or a dispenser method. The height of the first and second conductor interlayer connection protrusions 112 is required to be the thickness of the insulating layer determined by the design specifications of the substrate to be manufactured.

The first and second conductor interlayer insulator layers 120 are
It is a sheet made of an insulating resin and is a substrate member used for achieving electrical insulation between the first conductor layer 111 and the second conductor layer 121. The thickness is required to be the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured. The second conductor layer 121, the second conductor layer 121, and the second conductor layer insulator 120 are formed on the predetermined locations of the first and second conductor interlayer insulator layers 120 by the same method as the method of forming the first and second conductor interlayer connecting protrusions 112. Protrusions 122 for connecting three-conductor layers are formed. 2nd, 3rd
The height of the conductor-to-conductor connection 122 is required to be equal to the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured.

The second and third conductor interlayer insulator layers 130 are
It is a sheet made of an insulating resin and is a substrate member used for achieving electrical insulation between the second conductor layer 121 and the third conductor layer 131. The thickness is required to be the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured. The third conductor layer 131 and the third and third conductor layers 131 and 131 are formed by the same method as the method of forming the first and second conductor interlayer connecting protrusions 112 on the predetermined locations of the second and third conductor interlayer insulator layers 130. A protrusion 132 for 4-conductor interlayer connection is formed. 3rd and 4th
The height of the conductor interlayer connection protrusion 132 is required to be the thickness of the insulating layer determined by the design specifications of the substrate to be manufactured.

The third and fourth conductor interlayer insulator layers 140 are
It is a sheet made of an insulating resin, and is a substrate member used for achieving electrical insulation between the third conductor layer 131 and the fourth conductor layer 141. The thickness is required to be the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured. The upper stainless steel table 150 is a table for forming the fourth conductor layer 141 of the circuit pattern, and is made of a conductive material such as a stainless steel plate whose surface is mirror-finished so that the resin and copper are easily separated in the last step. It is desirable that it be made of a certain metal. In addition, this stainless steel upper stainless steel table 1
Reference numeral 50 not only serves as a base for forming the fourth conductor layer 141, but also serves as a press plate during hot pressing, and the thickness is required to be at least 1 mm or more, and there is no warp, and the surface. Is required to be smooth. Therefore,
The upper stainless steel table 150 is the lower stainless steel table 11
It has the same function as 0. Then, the fourth conductor layer 14 serving as a circuit pattern is formed on the smooth surface of the upper stainless steel table 150.
1 may be formed by electrolytic plating using a plating resist, but may also be formed by printing using a screen plate or the like using a paste or the like. Note that FIG. 1 shows a state after the fourth conductor layer 141 is formed, but is shown upside down for convenience of explanation of the structure of the substrate layer and the manufacturing method.

After the members of the part numbers 110 to 150 shown in FIG. 1 prepared as described above are stacked with high positional accuracy, they are pressed by a hot press to form a single multilayer substrate. The temperature applied during pressing is the insulation used for the first and second conductor interlayer insulator layers 120, the second and third conductor interlayer insulator layers 130, and the third and fourth conductor interlayer insulator layers 140. Although it depends on the type of body material, the optimum glass transition temperature of the resin used is generally about 20 to 30 ° C. For example, in the case of an epoxy resin, about 170
It is about 180 ° C. The pressing time is such that the first and second conductor interlayer insulator layers 120, the second and third conductor interlayer insulator layers 130 and the third and fourth conductor interlayer insulator layers 140 are melted, and the conductor circuit pattern It takes about 100 minutes to flow into the gap without any gap. And
The pressing force of the press needs to be about 25 kg / cm ² .

By the pressing operation as described above, the first and second conductor interlayer connecting protrusions 112, the second and third conductor interlayer connecting protrusions 122, and the third and fourth conductor interlayer connecting protrusions 132 are formed. , The first and second conductor interlayer insulator layers 12, respectively
1B through the 0th, 2nd, and 3rd conductor interlayer insulating layers 130 and the 3rd and 4th conductor interlayer insulating layers 140.
, The second conductor layer 121 and the third conductor layer 121, respectively.
The conductor layer 131 and the fourth conductor layer 141 are firmly pressed. Then, it becomes possible to make sufficient electrical connection with each. In this case, in order to further enhance the reliability of the connection, as shown in FIG.
Alternatively, it may be covered with a noble metal such as platinum (403). When each protrusion breaks through the insulating layer, the resin itself of the insulating layer is softened by the heat supplied from the hot press, so it is possible to break through each insulating layer resin very smoothly. . Even after the piercing is completed, since the insulating layer resin itself is melted, the periphery of the protrusion is filled with the resin without any voids, so that the quality of the multilayer substrate is also good.

As another method, as shown in FIG. 5, solder is applied to the tips of the connection portion projections 502 formed on the respective conductor circuit patterns 501 by an appropriate method to form the solder attachment portions 503. Once formed, each layer may be pressed. In this case, the following two methods (a) and (b) are suitable as the solder application method. (A) As shown in the left diagram of FIG. 6, only the tips of the connection portion projections 602 formed on the conductor circuit pattern 601 are immersed in the solder bath 603 in which the solder is heated and melted. As shown in the right diagram of FIG. (B) As shown in the left diagram of FIG. 7, the conductor circuit pattern 7
In the case where the connection portion projection 703 is formed on the 01 by using the connection portion forming plating resist 702,
Further, as shown on the right side of FIG. 7, the plating resist 702
Electrolytic solder plating is performed using
A solder attachment portion 704 may be formed at the tip of the. Although the reason will be described later, the solder to be used is preferably a solder having a composition having a melting point higher by about 10 ° C. or more than the curing temperature of the resin used for the inter-conductor-tank insulating layers 120, 130. .

8A to 8D are schematic diagrams showing the states of the main parts of each member at the time of pressing when solder is applied to the tips of the connection projections as shown in FIGS. Explained by. In this case, for simplification of description, solder is attached to the upper insulator layer 820 having the upper circuit pattern 821 formed thereon, the insulating resin sheet 810, and the tips of the connection protrusions 802 formed on the lower circuit pattern 801. A case of hot pressing the lower insulator layer 800 having the portion 803 will be described. In a), the drawing shows the arrangement state before pressing, but the solder attachment portion 803 is in a solid state. In b), the heat pressing proceeds, and the temperature of the supplied heat gradually rises from the room temperature, and when the temperature of the insulating resin exceeds the glass transition temperature, the resin softens. c) Eventually, the resin portion becomes in a fluidized state, gels when the temperature further rises, and finally becomes solid when the curing temperature is reached. During this process, the solder-attached portion 803 is
It has sufficient hardness to break through the insulating resin sheet 810 until the melting temperature of the curing temperature + 10 ° C. is reached. Then, the solder-attached portion 803 is the insulator resin sheet 810.
The upper circuit pattern 82 of the conductor layer on the other side
Pressed to 1. In addition, 811 is a resin part solidified after melting. d) When the temperature of the solder is melted by the heat supplied further, the solder is melted and becomes the melted solder portion 804. Then, when the pressing steps shown in a) to d) above are completed and the whole is cooled, the tips of the connection protrusions 802 and the upper circuit patterns 821 are firmly connected by the solidified solder.

In the case of the embodiment shown in FIG. 1, similarly to the above, the second and third conductor interlayer connection protrusions 122 and the third conductor layer 131, and the third and fourth conductor interlayer connection protrusions 132 are formed. And the fourth conductor layer 141 are pressure bonded. FIG. 1B shows a cross section of the substrate after the pressing is completed. Note that 160
Is a solidified resin layer after the entire insulating layer is melted and pressed. Thereafter, the unnecessary lower stainless steel table 110 and upper unnecessary stainless steel table 150 are peeled off to complete the multilayer substrate as shown in FIG. Since the surfaces of the lower stainless steel table 110 and the upper stainless steel table 150 are mirror-finished, they can be easily peeled off even after pressing. If necessary, a solder resist, solder, or the like is applied to the exposed portions of the first conductor layer 111, the fourth conductor layer 141, and the like to finish the finish.

In this embodiment, the upper and lower layer electrical connection projections penetrate the resin layer of the insulator, but the method is not limited to this. For example, the projections pass at the breakthrough positions. Holes of a certain size may be preliminarily opened with a drill, a laser, or the like, and protrusions may be fitted into the holes so that the holes are stacked according to the above-described embodiment. The procedure in the case of such a system will be described with reference to the schematic diagram of FIG. 311 is a lower conductor circuit pattern, and 312
Is a connection protrusion for electrically connecting the lower conductor circuit pattern 311 and the upper conductor circuit pattern (not shown). Further, 313 is a connection projection 312 is a hole for fitting, and 320 is an insulator layer resin sheet having a hole 313. Although detailed description is omitted, this method enables electrical connection between the conductor circuit patterns in the press without difficulty.

(Second Embodiment) FIGS. 2A and 2B are explanatory views of a substrate structure showing a second embodiment of the present invention. The left side view (a) is a state before press molding and the right side view (b) is press molding. The latter state is shown. This embodiment shows one application of the first embodiment,
It is characterized in that a conductor layer and a connecting portion projection are provided on both surfaces of one insulating resin. In the figure, 210
Is a plate-shaped lower stainless steel table for forming the first conductor layer 211 forming the circuit pattern, and is a stainless steel whose surface is mirror-finished so that the resin and the copper material are easily peeled off in the final step. It is made of conductive metal such as. The lower stainless steel table 210 serves not only as a table for forming the first conductor layer 211 but also as a pressing plate of the lower pressing jig during hot pressing, and has a thickness of at least 1 mm. It is necessary, and it is necessary that the surface without warpage is smooth. Then, the first conductor layer 2 to be a circuit pattern is formed on the smooth surface of the lower stainless steel table 210.
11 is formed by electrolytic plating using a plating resist, but may be printed by a screen plate using a paste or the like.

The first and second conductor interlayer insulator layers 220 are
It is a sheet made of an insulating resin, and is a substrate sheet used for achieving electrical insulation between the first conductor layer 211 and the second conductor layer 221. The thickness is required to be the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured.

The second and third conductor interlayer insulator layers 230 are
A sheet made of an insulating resin, which is a sheet for a substrate used for achieving electrical insulation between the second conductor layer 221 and the third conductor layer 231. The thickness is required to be the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured. On both surfaces of the second and third conductor interlayer insulator layers 230,
The second conductor layer 221 and the third conductor layer 231 and the first and second conductor interlayer connection protrusions 222 are formed by the same method as the method of forming the first and second conductor interlayer connection protrusions 112 of FIG.
And third and fourth conductor interlayer connecting protrusions 232.
The heights of the connection protrusions 222 and 232 are required to be the thickness of the insulating layer determined by the design specifications of the substrate to be manufactured.

The third and fourth conductor interlayer insulator layers 240 are
It is a sheet made of an insulating resin, and is a substrate member used for achieving electrical insulation between the third conductor layer 231 and the fourth conductor layer 241. The thickness is required to be the thickness of the insulating layer defined in the design specifications of the substrate to be manufactured. The upper stainless steel table 250 is a table for forming the fourth conductor layer 241 having a circuit pattern, and is made of a conductive material such as a stainless steel plate whose surface is mirror-finished so that the resin and copper are easily separated in the last step. It is desirable that it be made of a certain metal. In addition, this stainless steel upper stainless steel table 2
Reference numeral 50 not only serves as a base for forming the fourth conductor layer 241, but also serves as a pressing plate during hot pressing, and the thickness is required to be at least 1 mm or more, and there is no warpage, Is required to be smooth. The upper stainless steel table 250 has the same function as the lower stainless steel table 210. Then, the fourth conductor layer 241 which becomes a circuit pattern is formed on the smooth surface of the upper stainless steel table 250. The formation may be performed by electrolytic plating using a plating resist, for example, a screen plate using a paste or the like. Alternatively, the method of printing may be used.

Also in this case, hot pressing is carried out in the same manner as in the case of the first embodiment, and as shown in FIG. 2 (b), an integrated multi-layer substrate having the resin portion 260 which is solidified after melting is obtained. To be Then, the lower stainless steel table 210 and the upper stainless steel table 250 are peeled off and removed to complete the multilayer substrate of the mold of this embodiment. In the above description of the embodiments, the substrate having four conductor layers has been described as an example. However, the number of conductor layers is not limited to four, and any number of integer layers can be used. The manufacturing method of the invention is applicable.

(Third Embodiment) In this embodiment, other aspects of the structure of the connecting portion projection, particularly the tip portion will be described with reference to some embodiment examples of forming methods. First, as shown in FIG. 9, there is a method in which, after arranging the connection portion projections facing each other, they are pressed to crimp these projections. For example, as one example of electrical connection, a lower conductor layer 902 and a lower-side connection protrusion 903 are formed in this order on the lower insulator layer 901, and another upper conductor layer is formed below the upper insulator layer 906. 905 and an upper connecting portion protrusion 904 are formed in this order, and a lower connecting portion protrusion 903 and an upper connecting portion protrusion 904 are formed.
It is a method of pressing and facing each other and connecting them. In this case, the lower-side connecting portion projection 100 shown in FIG.
1 and the upper connecting portion projection 1002, by making the tip end into a hook shape, it is possible to significantly improve the substrate connectivity after pressing.

FIG. 11 is an explanatory view schematically showing the mechanism in which the upper and lower protrusions shown in FIG. 10 are connected during pressing. In the figure, a) of FIG. 11 shows the arrangement state before pressing, and the tip end of the lower-side connecting portion projection 1101 has a sliding surface 1
106 and a connection surface 1104 are formed. A sliding surface 1105 and a connecting surface 1103 are formed at the tip of the upper-side connecting portion projection 1102 so that the upper and lower tip portions face each other. The arrows indicate the respective press directions. The upper and lower protrusions due to the pressure at the time of pressing are shown in Fig. 11 b).
As shown in Fig. 2, the slip surface 110
5, 1106 come into contact with each other. Then, the slide surfaces further come into contact with each other on the slip surfaces, and finally, as shown in FIG. 11C, the connection is completed by engaging the connection surfaces 1103 and 1104 with each other. Since the insulating resin around the protrusions is in a molten state due to the heat during pressing during contact from the contact between the press and the protrusions as described above, there is no hindrance to the contact of the protrusions and the sliding meshing operation. It is like this. And with such a structure,
A strong connection is possible even for expansion and compression. Note that a noble metal film of gold, platinum, or the like may be provided on the connection surface in order to further increase the reliability of connection.

Here, a method of forming the above-mentioned protrusion will be described. The outline is shown in (a) and (b) of FIG.
First, as shown in FIG. 12A, electrolytic plating is performed using a plating resist 1201 on an insulator layer or a conductor layer 1202 formed on a stainless steel table, and first, there is no slip surface or connection surface. A connection protrusion 1203 is formed. Next, as shown in FIG. 12B, a plating resist 1204 for forming a shape having a slip surface having a shape as shown in FIG. 10 is formed. In this case, the plating resist 1204 used is for the reason described in detail later.
A dimerization reaction type curing reaction at the time of exposure is used. Next, plating is performed to form connection protrusions having hook-shaped protrusions as shown in FIG.

The reason why the dimerization reaction type resist is used as the plating resist will be described with reference to FIG. The dimerization reaction type resist does not cure the entire resist layer as in the radical reaction type, but only cures several μm from the resist surface to form a resist cured portion 1304, and the resist uncured portion 1305 is developed by development. The resist cut-away portion 130 in which the resist side wall is cut
A structure with 3 formed is obtained. As shown in FIG. 13, the lower squeezed portion 1302 is formed on the lower side of the side wall.
This is because the lower dent portion 1302 has strong adhesion to the base 1301. Therefore, as shown in FIG. 14, a surface treatment for reducing this adhesive force is previously performed on the underlayer to form a treatment film 1404 for reducing the resist adhesiveness, and a slipping / meshing surface forming surface is formed on the treatment film 1404. Resist 140
By forming No. 5, it is possible to form the hook-shaped projection by applying the method shown in FIG. 13 and plating the space formed on the projection 1403 and having a trapezoidal cross section. In the figure, reference numeral 1402 denotes a conductor layer formed on the base, on which a protrusion 1403 is formed. 1401 is a resist for forming a protrusion.
In order to form the above-mentioned treatment film 1404 for reducing the resist adhesiveness, a method of polishing the surface of the resist 1401 for forming the protrusion to a mirror surface may be used, or a substance having a low adhesiveness with other substances such as Teflon resin may be used. A method such as coating may be used. According to the forming method shown in FIG. 14, the projection tip structure for sliding engagement is formed in all directions without the need for sliding and engaging, but it can be used without any trouble.

In the above description of the third embodiment, only the shape and characteristics of the connecting portion have been described.
It goes without saying that the method shown in the first or second embodiment can be directly applied to the manufacture of the circuit board by using this connecting portion.

As described above in detail with reference to the first to third embodiments, the connecting portions between the upper and lower conductor layers are formed by protrusions like metal lumps, and the protrusions are made of an insulating material when press-forming a multilayer substrate. By breaking through the layer, the tip of the protrusion and the conductor layer can be easily brought into contact with each other, and pressure bonding and welding can be facilitated, so that a thin multilayer substrate can be manufactured easily and with high quality as compared with the conventional method. became. Moreover, unlike the conventional method for manufacturing a printed circuit board, it is not necessary to make holes for forming through holes by using an NC drill or the like, and the connection portion is formed by a protrusion, so that the connection can be performed with an area smaller than the diameter of the drill. Became possible. As a result, in combination with the above-mentioned effects, further miniaturization of the substrate circuit is achieved.

[0031]

As described above in detail, according to the present invention, the conductor inter-layer insulator layer forming the multilayer substrate is formed of a sheet-shaped insulator resin layer containing no glass fiber, and the conductor circuit layer is formed. A protrusion made of a conductor for electrical connection between conductor circuit layers is provided on a predetermined location of the insulator circuit layer, and the laminate resin is pressed by using a press jig plate so that the insulator resin layer is not protruded. It becomes easy to pierce or penetrate the insulating layer through a hole at a predetermined position provided in the insulating body, and contact the opposing conductor circuit layer.
Since the connection portion is formed by crimping, there is an effect that a thinner multilayer printed circuit board can be easily manufactured with high quality as compared with the conventional manufacturing method. Further, unlike the conventional multilayer board manufacturing, a fine drilling step for forming a through hole by an NC drill or the like is not necessary, and moreover, since the connecting portion is composed of small protrusions, the diameter is smaller than the diameter of the drill. Connection is possible with a small area. As a result, in combination with the above-mentioned effects, the contribution to achieving the miniaturization of the substrate circuit is great.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a substrate structure showing a first embodiment of the present invention, in which a left side view (a) shows a state before press molding and a right side view (b) shows a state after press molding.

2A and 2B are explanatory views of a substrate configuration showing a second embodiment of the present invention, in which a left side view (a) shows a state before press molding and a right side view (b) shows a state after press molding.

FIG. 3 is an explanatory diagram showing another mode of forming the connection portion according to the first embodiment of the present invention.

FIG. 4 is an explanatory view showing a mode of a tip end portion of a protrusion in the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing another aspect of the tip end portion of the protrusion in the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a method of forming the solder attachment portion of FIG.

FIG. 7 is an explanatory diagram showing another method for forming the solder-attached portion of FIG.

FIG. 8 is an explanatory diagram showing a state at the time of press molding by the protrusion of FIG.

FIG. 9 is an explanatory view of a tip end portion of a protrusion of a connection portion showing a third embodiment of the present invention.

FIG. 10 is a perspective view showing hook-shaped tip portions of the opposed protrusions of FIG. 9;

FIG. 11 is an explanatory diagram showing a connection state of the tip portion of FIG.

12 is a cross-sectional explanatory view showing one method of forming the hook-shaped tip portion of the protrusion of FIG.

FIG. 13 is an explanatory diagram showing the principle of another method of forming a hook-shaped tip portion using a dimerized resist.

FIG. 14 is an explanatory diagram showing the principle of another method of forming a hook-shaped tip portion using a dimerized resist.

[Explanation of symbols]

 110, 210 Lower stainless steel table 111, 211 First conductor layer 112 First and second conductor interlayer connection protrusions 120, 220 First and second conductor interlayer insulator layers 121, 221 Second conductor layer 122 Second and third conductor interlayer connection protrusions 222 First and second conductor interlayer connection protrusions 130 and 230 Second and third conductor interlayer insulator layers 131 and 231 Third conductor layer 132 and 232 Third , Fourth conductor interlayer connection protrusion 140,240 third, fourth conductor interlayer insulating layer 141,241 fourth conductor layer 150,250 upper stainless steel table 160 solidified resin layer 260 solidified resin portion after melting 311 Lower conductor circuit pattern 312 Connection protrusion 313 Hole 320 Insulator layer resin sheet 401 Conductor circuit pattern 402 Connection protrusion 403 Gold (or platinum) 501, 01,701 Conductor circuit pattern 502,602,703 Connection part protrusion 503 Solder adhesion part 603 Solder bath 702 Plating resist 604,704,803 Solder adhesion part 800 Lower insulator layer 801 Lower circuit pattern 802 Connection part protrusion 804 Melted Solder portion 810 Insulator resin sheet 811 Resin portion solidified after melting 820 Upper insulator layer 821 Upper circuit pattern 901 Lower insulator layer 902 Lower conductor layer 903 Lower side connection protrusion 904 Upper side connection protrusion 905 Upper conductor Layer 906 Upper insulating layer 1001 Lower side connecting portion protrusion 1002 Upper side connecting portion protrusion 1101 Lower side connecting portion protrusion 1102 Upper side connecting portion protrusion 1103, 1104 Connecting surface 1105, 1106 Sliding surface 1201, 1204 Plating resist 1202 Conductor layer 203 connection protruding 1301 base 1302 lower deflated portions 1303 resist gouging portions 1304 resist cured portions 1305 resist uncured portion 1401 protruding forming resist 1402 conductive layer 1403 projections 1404 treated film 1405 slip-engaging surface forming resist

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Susumu Ozawa 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (5)

[Claims] 1. A pressing jig having a conductor circuit layer, which is a laminate obtained by stacking a predetermined number of an insulator layer having a conductor circuit layer on both sides or one side and the insulator layer having no conductor circuit layer. A method for manufacturing a printed circuit board, comprising pressurizing and molding from both end faces using a plate, and at the same time electrically connecting at least two upper and lower conductor circuit layers to each other to form a multilayer printed circuit board. Both are formed of a sheet-shaped insulator resin layer containing no glass fiber, and a protrusion made of a conductor for electrical connection between the conductor circuit layers is provided on a predetermined place of the conductor circuit layer. A printing method characterized in that the protrusion is pierced through the insulating resin layer by pressure applied by pressing the laminated body using the pressing jig plate, and the insulating resin layer is brought into contact with and pressure-bonded to the opposing conductor circuit layer. Road substrate manufacturing method. 2. The means for causing the protrusion to pierce the insulating resin layer, in addition to the pressure, heats up to the melting temperature of the insulating resin layer to facilitate the piercing of the protrusion. Item 2. A method for manufacturing a printed circuit board according to item 1. 3. In place of the means for the protrusion to break through the insulating resin layer, a hole having a size through which the protrusion passes is formed in advance at a position where the protrusion penetrates, and the protrusion passes through the hole during pressing. The method for manufacturing a printed circuit board according to claim 1, wherein the conductor circuit layers facing each other are brought into contact with and pressed against each other. 4. A solder layer having a melting temperature higher than the resin curing temperature of the insulator resin layer is provided at the tip of the protrusion, and the insulator resin layer is pierced by the protrusion by the heat and pressure. The solder layer is brought into pressure contact with the conductor circuit layer,
After the insulating resin layer is cured, the temperature is raised to the melting temperature of the solder in this state to melt the solder layer and connect the protrusion to the conductor circuit layer, and then cool the solder. The method for manufacturing a printed circuit board according to claim 2, wherein the layer is solidified. 5. The protrusion provided on the conductor circuit layer forming the connection portion is provided at the same position of the upper and lower insulating resin layers so that the tip portions thereof face each other, and the connection is made at the tip portion of the protrusion. 3. The method of manufacturing a printed circuit board according to claim 2, wherein the parts are provided with a surface that is in contact with each other and slides during pressing, and a surface that is in mesh with each other and is in contact with each other.