JPH0818228A - Manufacture of multi-layer printed board - Google Patents

Abstract

PURPOSE:To provide a highly precise, light weight and downsized multi-layer printed board by a simple method corresponding to a high-density conductor pattern. CONSTITUTION:A double-sided board 3 is provided by forming a conductor pattern 5 and a land 6 by photo-etching a copper foil. On one side of a thick copper foil 7, only thermosetting resin 8 which does not have a glass cloth core 4 is applied to provide basic material 9. The basic material 9 is adhered on the double-sided board 3; a via hole 10 is etched on the copper foil layer using photoresist to expose the surface of the resin layer; and a via hole 11 is etched on the exposed resin layer by laser using the copper foil layer as a mask. Thus, the amount of the conductor wiring pattern is remarkably improved allowing other characteristics such as heat resistance and electric characteristic to be the same as those of multi-layer boards manufactured by other methods, and interconnection between layers is can freely be formed. Reduction of material allows weight reduction, and since the number of processes is reduced and manufacture is simplified, cost is reduced.

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 multilayer printed wiring board, and more particularly to a method for manufacturing a multilayer printed wiring board excellent in wiring efficiency and capacity of a conductor pattern.

[0002]

2. Description of the Related Art In recent years, electronic devices are becoming smaller, faster, and more multifunctional, and the volume occupied by printed wiring boards in devices is becoming a problem. There is a demand for a method for manufacturing a multilayer printed wiring board in which holes are obtained by a laser method.
(See, for example, Japanese Patent Publication No. 4-3676.) In this method of manufacturing a multilayer printed wiring board, double-sided or single-sided, and mechanically forming via-hole holes in the multi-layered board and plating the both sides or single-sided IV of the method of forming a conductor pattern and stacking two or more sheets
H (interstitial via hole) and SVH (surface via hole) methods are available. This method, which is currently the mainstream, has the drawback that it is difficult to form minute holes because it is mechanically drilled, and it is difficult to form a high-density pattern because it is plated several times. is there.

[0003]

In order to solve these problems, there is a method in which after laminating, a hole is drilled from the outermost layer to the lower layer or two or three layers after lamination, but usually the insulation of the laminated plate is used. There is a glass cloth between the layers that should be formed, and there is a problem that the glass cloth breaks the drill even if the smallest diameter drill of 0.15 mm is used. There is also a method of forming a high-density pattern by stacking the photoresist using a method similar to the additive method, but forming a via hole with the photoresist and plating the resist on the conductor pattern. Therefore, the diameter is 60 μm to 80 μm, which is about the same as the resist thickness, and it is not a perfect circle or a cylinder with less mechanical and thermal stress. Also, the conductor pattern is not adhered well and is not generally used. .

An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board, which is capable of accommodating a high density of a conductor pattern and which can achieve high precision, light weight and size reduction by an easy method. Is to provide.

[0005]

In order to achieve the above object, the present invention provides a double-sided plate or a single-sided plate having a conductor pattern and a land formed by photoetching a copper foil attached to both sides or one side of a substrate. On the above, in the method for manufacturing a multilayer printed wiring board in which a base material made of a copper foil and a resin is laminated, the base material is a thermosetting resin having no glass cloth on one side of the rolled copper foil. Is used.

Further, in the method for manufacturing a multilayer printed wiring board, a double-sided plate or a single-sided plate on which the conductor pattern and lands are formed is coated with a base material obtained by applying only a thermosetting resin to one surface of a thick-rolled copper foil. Pasting without interposing a cloth, etching the holes for via holes using a photoresist in the rolled copper foil layer to expose the surface of the resin layer, and the resin layer exposed using the rolled copper foil layer as a mask A laser is used to etch the holes for the via holes.

In the method of manufacturing a multilayer printed wiring board, a step of preparing a substrate on which a copper foil is stuck,
Photoetching the copper foil, forming a conductor pattern and a land, and a step of preparing a base material in which only a thermosetting resin is applied to one surface of the thick rolled copper foil,
A step of sticking the resin layer side of the base material on the substrate on which the conductor pattern and the land are formed, and etching the holes for via holes using a photoresist in the copper foil layer of the base material to form the resin A step of exposing the surface of the layer; a step of etching a hole for a via hole in the exposed resin layer by using a laser with the copper foil layer as a mask; and a hole for a via hole of the resin layer In a place other than the step of forming a through hole for a through hole in the central portion of the land formed on the substrate,
The method comprises forming a conductor pattern and a via hole in the copper foil layer of the base material by forming a circuit by the subtractive method, and at the same time forming a through hole.

Further, a step of pasting the resin layer side of the base material on the substrate on which the conductor pattern and the land are formed, and a hole for a via hole are formed in the copper foil layer of the base material by using a photoresist. Instead of the step of etching to expose the surface of the resin layer, and using the copper foil layer as a mask, the step of etching holes for via holes using a laser in the exposed resin layer, In the copper foil layer and the resin layer of the base material, a step of previously forming a through hole for a via hole using a drill, and the base material having the through hole formed on the substrate on which the conductor pattern and the land are formed. A step of sticking can be added, and these steps may be appropriately repeated a predetermined number of times to manufacture a multilayer printed wiring board.

[0009]

According to the above construction, since the glass cloth provided in the conventional multilayer printed wiring board is not interposed between the board and the substrate, it is easy to form via holes, through holes, etc., and the material is reduced, so that the size and weight are reduced. Can be realized. In addition, since the conventional lamination technology can be used, for example, a thin copper foil having a thickness of 9 μ to 5 μ can be used, it is possible to adhere to the conductor pattern and increase the density, and a via hole having a diameter of 10 μ is formed by the laser method. It is possible to Therefore, the capacity for accommodating the conductor pattern is sufficient, and a high-density and small-sized multilayer printed wiring board can be manufactured.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a process drawing of a first embodiment of the present invention, which is a sectional view of a substrate in each process of manufacturing a four-layer printed wiring board. This example includes the following steps.

First, as a first step, as shown in step A of FIG. 1, a double-sided plate 3 in which copper foils 2 are attached to both surfaces of a substrate 1 is prepared. The substrate 1 is provided with a glass cloth core 4 for insulating between the copper foils 2 on both sides. In addition, although the double-sided plate 3 is used in this embodiment, the manufacturing process is the same as that of the single-sided plate in which the copper foil is adhered only on one side instead.

Next, as a second step, as shown in step B of FIG. 1, the copper foils 2 on both sides of the double-sided plate 3 are photo-etched to form conductor patterns 5 and lands 6.

As a third step, as shown in step C of FIG. 1, a base material 9 is prepared by coating only one side of a thick rolled copper foil 7 with a thermosetting epoxy resin 8. The base material 9 is not provided with an insulating glass cloth core. In this embodiment, an epoxy resin is used, but a polyimide resin can be used as well.

Next, as a fourth step, as shown in step D of FIG. 1, the resin 8 layer side of the base material 9 is attached from both surfaces of the substrate 1 on which the conductor patterns 5 and the lands 6 are formed. In this embodiment, no glass cloth core is interposed in this resin 8 layer.

Next, as a fifth step, as shown in step E of FIG. 2, the holes 10 for the via holes are etched by using a photoresist on the layer of the copper foil 7 of the base material 9 to remove the resin 8. Expose the surface of the layer.

As a sixth step, as shown in step F of FIG. 2, the hole 11 for the via hole is etched using a layer of the copper foil 7 as a mask and using a laser on the exposed layer of the resin 8. Then, the conductor pattern 5 is exposed. At this time, the holes 11 are washed with a chemical such as permanganate, if necessary.

Next, as a seventh step, as shown in step G of FIG. 3, a through hole 12 for a through hole is formed in the central portion of the land 6 formed on the substrate 1 except the hole 11. Form.

Next, as an eighth step, a circuit pattern is formed by a subtractive method to form a conductor pattern and a via hole in the copper foil layer of the base material and simultaneously form a through hole. That is, as shown in step H of FIG.
Then, copper plating 13 having a thickness of 20 μ is electrolytically formed. Further, as shown in step I of FIG. 3, the conductor pattern 1 is reversely formed using a photoresist and solder plating is performed to a thickness of 8 μ
After 10 μm, the photoresist is peeled off and the conductor pattern 14 is formed by etching.

According to the present embodiment, since the glass cloth core is omitted, the holes for via holes can be processed and formed with high precision and easily.

(Embodiment 2) Next, a second embodiment of the present invention will be described. The difference of this embodiment from the first embodiment is that instead of steps E and F shown in FIG. 2, a copper foil layer and a resin layer of the base material 9 are formed as step J as shown in FIG. ,
Pre-drilled through hole 15 for via hole
(Corresponding to the hole 11 in FIG. 2) is formed, and this is attached to both surfaces of the substrate 1 to be the same as the step F in FIG.
In the present embodiment, the through hole 12 shown in step G of FIG.
Although the hole corresponding to is not formed, it may be drilled in advance. This embodiment also has the same effect as that of the first embodiment.

(Embodiment 3) Next, as a third embodiment of the present invention, a method for producing a multi-layer board having five or more layers will be described. In this embodiment, at the stage where the process F of FIG.
A predetermined multilayer board can be manufactured by attaching the base material shown in step C of FIG. 1 to both sides or one side of the layer board and repeating steps E and F of FIG.

Further, as explained in the second embodiment shown in FIG. 4, a base material having through holes for via holes formed in advance by using a drill is attached to both sides or one side of a four-layer plate to form a multilayer structure. It can also be a plate.

In this case, the formation of the through hole for the through hole at the center of the land by the drill at a place other than the hole for the via hole may be performed in the final step or may be appropriately performed in the intermediate step. Of course.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described. In this embodiment, as shown in FIG.
It is one Example of the manufacturing method of the 6-layer board which laminates the copper foil 20 of the 6th layer. Two base materials 22 in which a thermosetting epoxy resin 21 is applied to one surface of the copper foil 20 to be the first layer and the sixth layer, the second layer and the third layer, and the fourth layer and the fifth layer. Two double-sided plates having layers on both sides and a prepreg between the third layer and the fourth layer, a total of five layers, were laminated to form a via-layer on the copper foil 20 on both surfaces of the six-layered plate. The holes are etched using photoresist so that the epoxy resin is exposed.

Next, the land of the second and fifth layers below is sublimated by a laser method, and the inside of the via hole is cleaned with a chemical such as permanganate for resin etching. Next, a through hole for penetration is opened, electroless and electrolytic copper plating with a thickness of 20μ is performed, a conductor pattern is reversely formed using photoresist, and solder plating is performed with a thickness of 8μ to 10μ, and the photoresist is peeled off. Then, a conductor pattern was formed by etching to manufacture a 6-layer board similar to the 4-layer board shown in step I of FIG.

Also in this embodiment, the first layer and the sixth layer
Since the two base materials 22 in which the thermosetting epoxy resin 21 is applied to one surface of the layered copper foil 20 are made of a new material without a glass cloth core, a high density is obtained as in the first embodiment. It was possible to manufacture a small multilayer wiring board.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. The present embodiment is an example of a method for manufacturing an 8-layer board, and the method is shown in FIG.
The base material coated only with the thermosetting epoxy resin is laminated on one surface of the copper foil shown in step C of 1., and the holes for via holes are formed in the copper foil on both surfaces of the single 8-layer board. Etching is performed using a resist so that the epoxy resin is exposed.

Next, as described in the fourth embodiment, the land of the lower layer is sublimated by the laser method,
Clean the inside of the via hole with a chemical for resin etching. Next, through holes for penetration were formed, electroless and electrolytic copper plating was performed, a conductor pattern was formed and solder plating was performed, and a conductor pattern was formed by etching to manufacture a high-density small board. Further, by repeating this method, it is possible to manufacture a high-density small-sized multilayer board capable of any wiring method.

[0029]

As described above, according to the present invention,
The various properties such as heat resistance and electrical properties are no different from those of the multilayer board manufactured by other manufacturing methods, and the accommodating capacity of the conductor wiring pattern is significantly improved, and the wiring between layers can be freely performed. Further, by omitting the material, the weight can be reduced, the number of working steps can be reduced, and the manufacturing method can be simplified, so that the cost can be reduced. Therefore, it is widely applied and extremely industrially useful in the field of high-density and miniaturized electronic devices.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view for explaining a manufacturing process of a four-layer printed wiring board that is a first embodiment of the present invention,
Step A is a copper-clad substrate, step B is a copper-clad substrate is photo-etched to form a conductor pattern, step C is a base material of the present invention in which only a copper foil is coated with resin, and step D is a substrate of the present invention. It is a figure which shows the place which stuck the base material.

FIG. 2 is a cross-sectional explanatory view for explaining a manufacturing process after FIG. 1, in which a hole for a via hole is etched and opened in a step E, and a hole is formed in a resin layer by a laser in a step F. It is a figure which shows the place which opened.

FIG. 3 is a cross-sectional explanatory view for explaining a manufacturing process after FIG. 2, in which a through hole is drilled in step G, and plating is performed in step H for conduction,
Step I is a diagram showing that the conductor pattern of the outer layer is etched.

FIG. 4 is a cross-sectional explanatory view for explaining a manufacturing process of the second embodiment of the present invention, wherein step J is a via hole previously drilled on the base material of the present invention in which only the resin is applied to the copper foil. It is a figure which shows the place which opened the hole for holes.

FIG. 5 is an explanatory diagram of a method for manufacturing a 6-layer board that is the fourth embodiment of the present invention.

[Explanation of symbols]

 1 Base Material 2 Copper Foil 3 Double-Sided Plate 4 Glass Cross Core 5 Conductor Pattern 6 Land 7 Copper Foil 8 Epoxy Resin 9 Base Material 10 Hole 11 Hole 12 Through Hole 13 Plating 14 Conductor Pattern 15 Through Hole 20 Copper Foil 21 Resin 22 Base Material

─────────────────────────────────────────────────── ───Continued from the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H05K 3/40 Z 7511-4E

Claims (9)

[Claims] 1. A base material made of a copper foil and a resin is laminated on a double-sided plate or a single-sided plate having a conductor pattern and lands formed by photo-etching a copper foil attached to both sides or one side of a substrate. In the method for manufacturing a multilayer printed wiring board, the base material is a rolled copper foil coated on one side with a thermosetting resin having no glass cloth. Manufacturing method. 2. A base material made of a copper foil and a resin is laminated on a double-sided plate or a single-sided plate having a conductor pattern and lands formed by photo-etching a copper foil attached to both sides or one side of a substrate. In the method for manufacturing a multilayer printed wiring board, a double-sided plate or a single-sided plate on which the conductor pattern and lands are formed, one side of a thick-rolled copper foil, a base material coated only with a thermosetting resin, and a glass cloth interposed Without applying, to expose the surface of the resin layer by etching holes for via holes using a photoresist in the rolled copper foil layer, a laser to the resin layer exposed using the rolled copper foil layer as a mask A method for manufacturing a multilayer printed wiring board, which comprises using the holes for etching via holes. 3. A method for manufacturing a multilayer printed wiring board, the step of preparing a substrate on which a copper foil is stuck, the step of photo-etching the copper foil to form a conductor pattern and a land, and one side of a thick copper foil. A step of preparing a base material to which only the thermosetting resin is applied, a step of pasting the resin layer side of the base material on the substrate on which the conductor pattern and the land are formed, and copper of the base material Etching holes for via holes using a photoresist in the foil layer to expose the surface of the resin layer; and using the copper foil layer as a mask, the exposed resin layer is exposed to vias using a laser. A step of etching a hole for a hole; a step of forming a through hole for a through hole at a central portion of a land formed on the substrate at a position other than the hole for a via hole of the resin layer; The circuit formed by law, method for manufacturing a multilayer printed wiring board, wherein when forming the conductive pattern and via holes in the copper foil layer of the substrate and forming at the same time through holes, in that it consists of. 4. A method for manufacturing a multilayer printed wiring board, the step of preparing a substrate with a copper foil attached thereto, the step of photo-etching the copper foil to form a conductor pattern and a land, and one side of a thick rolled copper foil. A step of preparing a base material coated only with a thermosetting resin, a step of previously forming a through hole for a via hole using a drill in the copper foil layer and the resin layer of the base material, A step of pasting the base material in which the holes are formed on the substrate on which the conductor pattern and the lands are formed, and at a place other than the holes for the via holes of the resin layer, in the central portion of the land formed on the substrate. A step of forming a through hole for a through hole, and a step of forming a through hole at the same time as forming a conductor pattern and a via hole in the copper foil layer of the base material by forming a circuit by a subtractive method, Method for manufacturing a multilayer printed wiring board, characterized in that Ranaru. 5. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein a through hole is provided at a central portion of a land formed on the substrate, other than a hole for the via hole of the resin layer. Before the step of forming the through-hole, the resin layer side of the base material is pasted on the substrate on which the conductor pattern and the land are formed, and a via hole is formed on the copper foil layer of the base material using a photoresist. Etching the holes for exposing the surface of the resin layer, using the copper foil layer as a mask, and etching the holes for via holes using a laser in the exposed resin layer, or A step of previously forming a through hole for a via hole in a copper foil layer and a resin layer of a base material by using a drill, and pasting the base material having the through hole formed on the substrate on which the conductor pattern and the land are formed. Method for manufacturing a multilayer printed wiring board and performing predetermined times either or both steps of. 6. The method for manufacturing a multilayer printed wiring board according to claim 5, wherein a via of the resin layer is provided a predetermined number of times before the step of forming a through hole for a through hole in the central portion of the land. A method for manufacturing a multilayer printed wiring board, comprising the step of forming a through hole for a through hole with a drill in a central portion of a land formed on the substrate at a place other than the hole for the hole. 7. The method for manufacturing a multilayer printed wiring board according to claim 5, wherein the resin layer is formed on the substrate only in a final step of the steps other than the holes for the via holes of the resin layer. A method for manufacturing a multilayer printed wiring board, characterized in that a through hole for a through hole is formed by a drill in the central portion of the land. 8. The method for manufacturing a multilayer printed wiring board according to claim 3, wherein the substrate is a double-sided plate or a single-sided plate in which copper foil is attached on both sides or one side, and the copper foil is A method for producing a multilayer printed wiring board, comprising laminating the base material on a surface on which the material is pasted. 9. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the resin layer of the base material is made of epoxy or polyimide. Production method.