JPH08316631A - Manufacture of multilayer wiring board - Google Patents

Abstract

PURPOSE: To manufacture a multilayer wiring board with a high wiring density and improved working efficiency by laminating a film-shaped material which is drilled on an inner-layer circuit substrate in one piece, eliminating carriers, and performing plating via a hole, and forming a circuit. CONSTITUTION: An adhesive containing macromolecular epoxy polymer is applied to one surface of an extremely thin copper foil with carrier (a) for semi-curing (b). Then, a part which becomes a via hole is drilled (c). Then, a copper-clad lamination plate is prepared and an inner-layer circuit substrate is prepared by the normal etched wheel method (d). Then, a drilled copper foil coated with adhesive is attached to the inner-layer circuit substrate to form a laminate (e). Then, a through hole is drilled (f), aluminum which is a carrier is peeled off (g), smear treatment is performed by a solution containing permanganate and alkali, and plating is made for depositing plated metal, thus creating a wiring board (h).

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 wiring board.

[0002]

2. Description of the Related Art Generally, the density of a multilayer wiring board is increased by increasing the number of wiring layers. However, if the number of wiring layers is simply increased, a through hole (hereinafter referred to as a through hole) for connecting the wiring of each layer will be used. The number of holes) increases, the area occupied by the through holes increases, and the amount of wiring accommodated decreases. Therefore,
There has been proposed a method in which a connection hole is provided only at a place where connection is required and a non-through hole (hereinafter referred to as a via hole) is formed.

For example, as disclosed in Japanese Patent Application Laid-Open No. 2-62095, a reinforcing material such as a protective metal foil is provided on one surface and an adhesive sheet is attached to the other surface to form a via hole. In advance, a hole is made in advance, the inner layer circuit board is laminated and adhered, and the inner wall of the via hole is metalized,
Methods of making connections are known.

[0004]

By the way, a reinforcing material such as a metal foil for protection is provided on one surface, an adhesive sheet is attached to the other surface, and a hole is preliminarily formed at a position to be a via hole. In addition, the method of laminating and adhering to the inner layer circuit board, metalizing the inner wall of the via hole, and making the connection requires the steps of forming an adhesive sheet and bonding with a copper foil, which complicates the manufacturing process. However, in order to handle the adhesive sheet as a single body, there is a problem that the adhesive layer must be provided with flexibility by using a rubber component having low heat resistance.

As a result of earnest studies, the inventors of the present invention have proposed a method of applying an adhesive to a copper foil to reduce the number of steps and not using a rubber component having low heat resistance, as disclosed in Japanese Patent Application No. 6-140028. Have proposed by. However, even in this method, when the copper foil is 12 μm or less, the problem of curling occurs as shown in FIG. Further, the curled material not only significantly lowers the work efficiency in the perforation and the multi-layer lamination adhesion step, but also when the curl is corrected to be flat, the thin copper foil may be broken.

An object of the present invention is to provide a method for manufacturing a multilayer wiring board having a high wiring density and excellent work efficiency.

[0007]

The method for manufacturing a multilayer wiring board according to the present invention comprises: a. A step of forming a hole in a predetermined position of a film material having an A-stage or B-stage insulating adhesive layer formed on one surface of an ultra-thin copper foil with a carrier. B. A step of stacking the perforated film-shaped material on the inner layer circuit board so that the circuit board and the insulating adhesive layer are in contact with each other, and heating and pressurizing to laminate them together c. Step of removing carrier d. A step of electrically connecting a circuit on the inner layer circuit board and a copper foil of the film-like material by plating through a hole provided in the film-like material from which the carry has been removed; e. The method is characterized by having a step of processing a copper foil of a film material to form a circuit.

For this carrier, a metal foil or an organic material sheet having a high elastic modulus at high temperature can be used. As the metal foil, a metal foil such as copper or aluminum, and an adhesive or the like coated on these metal foils. Examples thereof include those produced by plating a copper foil with a dissimilar metal, and the like. For example, 7
Peelable electrolytic copper foil (trade name of Furukawa Circuit Foil Co., Ltd.) consisting of 0 μm thick aluminum foil and 5 μm thick copper foil, 40E5 with copper foil thickness of 5 μm
(Mitsui Metal Industry Co., Ltd., trade name), the thickness of the copper foil is 9
There is 40 μm (trade name) manufactured by Mitsui Kinzoku Kogyo Co., Ltd., etc. Further, as the organic material sheet, polyimide,
Organic material sheets such as polyethylene terephthalate, polypropylene, polyvinylidene chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, polyacrylonitrile, polyamide, and cellophane can be used.

The composition of the insulating adhesive layer which can be used in the present invention is an epoxy resin adhesive, an acrylic modified resin system,
Alternatively, a polyimide resin adhesive or the like can be used. The insulating adhesive layer needs to be semi-cured, and it is possible to experimentally determine a drying condition after coating on the copper foil, which is not enough to completely cure. In the present invention,
At 40 ° C. or lower, it means a state in which it has no tackiness and gives an adhesive strength of 0.6 kgf / cm or more by multilayer adhesion.
As such an insulating adhesive, for example, AS-3000 (manufactured by Hitachi Chemical Co., Ltd., trade name) is commercially available, and as an adhesive coated on a copper foil, MCF-
There is 3000 (trade name, manufactured by Hitachi Chemical Co., Ltd.).

[0010]

【Example】

Example On a copper foil surface of a peelable electrolytic copper foil (trade name, manufactured by Furukawa Circuit Foil Co., Ltd.) as shown in FIG. 3 (a), as shown in FIG. 3 (b), a high molecular weight of 100,000 or more was obtained. The adhesive containing the molecular epoxy polymer has a thickness of 50 μm after drying.
So that it is semi-cured. No curl occurred at this time. As shown in FIG. 3 (c), a hole having a diameter of 0.3 mm is drilled at a place to be a via hole. As shown in FIG. 3 (d), a copper-clad laminate having a thickness of 0.3 mm is prepared, and by a usual etched foil method,
Create the inner layer circuit board. As shown in FIG. 3 (e), a copper foil coated with an adhesive having holes is placed on the inner layer circuit board, and a temperature of 170 ° C. and a pressure of 25 kgf / cm ² are applied for 60 minutes to perform multi-layer adhesion. Unify. As shown in FIG. 3 (f), through holes are opened, and as shown in FIG. 3 (g),
The carrier aluminum is peeled off mechanically,
As shown in FIG. 3 (h), smear treatment is performed with a solution containing permanganate and an alkali, plating is performed to deposit a plating metal having a thickness of 20 μm, an etching resist is formed, and unnecessary copper is removed. By removing by etching, a wiring board having circuit conductors having a width and a spacing of 60 μm is formed.

Comparative Example 1 Wiring was performed in the same manner as in Example 1 except that a copper foil having a thickness of 12 μm was used in place of the peelable electrolytic copper foil (trade name, manufactured by Furukawa Circuit Foil Co., Ltd.) of Example 1. I tried to make a plate, but curling occurred and I could not punch or stack.

Comparative Example 2 As a result of using a copper foil of 18 μm in place of the copper foil of Comparative Example 1, curling does not occur, and a wiring board similar to that of Example 1 can be prepared.

[0013]

As described above, according to the present invention, it is possible to provide a method for manufacturing a multilayer wiring board having a high wiring density and excellent work efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a problem of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

3 (a) to 3 (h) are cross-sectional views in each step for explaining one embodiment of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Atsushi Takahashi 1500 Ogawa, Shimodate, Ibaraki Shimodate Research Laboratory, Hitachi Chemical Co., Ltd. (72) Inventor ▲ Tsuru ▼ Yoshino, 1500 Ogawa, Shimodate, Ibaraki Shimodate Research Institute Co., Ltd. (72) Inventor Shigeharu Ariya 1500 Ogawa, Shimodate, Ibaraki Hitachi Chemical Co., Ltd. Shimodate Research Institute (72) Inventor Kazuhisa Otsuka 1500 Ogawa, Shimodate City, Ibaraki Hitachi Chemical Co., Ltd. Shimodate In the laboratory

Claims (5)

[Claims] 1. A. On one side of the ultra-thin copper foil with carrier,
A step of forming a hole in a predetermined position of the film-shaped material on which an A-stage or B-stage insulating adhesive layer is formed. B. A step of stacking the perforated film-shaped material on the inner layer circuit board so that the circuit board and the insulating adhesive layer are in contact with each other, and heating and pressurizing to laminate them together c. Step of removing carrier d. A step of electrically connecting a circuit on the inner layer circuit board and a copper foil of the film-like material by plating through a hole provided in the film-like material from which the carry has been removed; e. A method for manufacturing a multilayer wiring board, which comprises a step of processing a copper foil of a film material to form a circuit. 2. The thickness of the copper foil of the ultra-thin copper foil with a carrier is 1
The method for manufacturing a multilayer wiring board according to claim 1, wherein the thickness is 2 μm or less. 3. The method for producing a multilayer wiring board according to claim 1, wherein the carrier is any one of copper foil, aluminum and resin film. 4. The method for manufacturing a multilayer wiring board according to claim 1, wherein the carrier is removed by peeling it off. 5. The method for manufacturing a multilayer wiring board according to claim 1, wherein the carrier is removed by a chemical etching solution.