JPH07226584A - Manufacture of multilayer wiring board wherein copper foil with insulation bonding material is used - Google Patents

Abstract

PURPOSE:To realize a thin type of a large number of laminations by forming a circuit pattern of metal whose etching conditions are different from those of copper in a copper foil surface of a copper clad lamination board, by etching and removing the copper foil thereafter, by boring a hole in a specified position of an insulation bonding sheet, by laminating the sheet for lamination integration and by forming a circuit including interlaminar connection. CONSTITUTION:Plating resist 3 is formed in a surface of a copper foil 2 on a base material 1 to expose the copper foil 2. After a circuit pattern is formed by electrolytic nickel plating whose etching conditions are different from those of copper, the copper foil 2 is etched and removed. A hole is bored in a fixed position of an insulating bonding sheet 4, the sheet 4 is laminated and they are made integral by lamination. Thereby, a thin type can be realized even in case of a large number of laminations.

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 using an insulating adhesive material sheet.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and thinner, multilayer wiring boards have also been required to be thinner. Therefore, a method for forming a multilayer wiring board that does not use a glass base material has been studied. Instead of using only a through hole that penetrates the entire wiring board by drilling holes, only adjacent wiring layers are connected. A method of forming a so-called interstitial via hole has been developed. As such an example, an insulating adhesive sheet having a hole for interlayer connection or a hole for a cavity for mounting a semiconductor or an insulating adhesive sheet with a copper foil is laminated on a circuit board, and a method such as plating is used. There is a method of forming a circuit by.

[0003]

The method of using an insulating adhesive sheet or an insulating adhesive sheet with a copper foil can be made thinner than the conventional method of adhering a glass epoxy single-sided board, a multilayer board, or a flexible board. When a certain point or its material is selected, it is excellent in heat resistance. In addition, it is preferable to form a cavity so that the circuit board is partially exposed, because terminals can be formed on the exposed portion and chips can be mounted. However,
In the method of using an insulating adhesive sheet or an insulating adhesive sheet with copper foil, the copper foil is exposed in the holes and cavities. The clogged material must be removed after processing, which is not efficient.

It is an object of the present invention to provide a highly efficient method for producing a wiring board using such an insulating adhesive sheet.

[0005]

According to the method for manufacturing a multilayer wiring board of the present invention, a circuit pattern is formed on a copper foil surface of a copper-clad laminate by a metal having an etching condition different from that of copper and exposed. The copper foil is removed by etching, and on the circuit,
Forming a circuit including interlayer connections by stacking insulating adhesive sheets or insulating adhesive sheets with copper foil that have been punched in place so that the insulating adhesive sheets contact the circuits. Is characterized by.

Further, by repeating these series of steps any number of times, it is possible to form a multilayer wiring having three or more layers.

In the present invention, as a method for forming a pattern in a circuit shape on a copper foil surface of a copper-clad laminate using a metal having an etching condition different from that of copper, a plating resist is formed on a portion which does not form a circuit. , A method of plating a metal having a different etching condition from copper, or a metal having a different etching condition from copper is plated on the entire surface of the copper foil of the copper-clad laminate, and an etching resist is formed on the circuit shape. However, a method of etching away only the metal can be used.

At this time, the plating may be electroless plating, but electrolytic plating is preferable in terms of efficiency.

There are nickel, gold, solder, tin, alloys thereof, etc. as a type of metal resist for forming a pattern in a circuit shape with a metal having an etching condition different from copper. One or two of these are used. You may use it in combination of 2 or more types.

In order to press-heat and integrate the insulating adhesive sheet or the insulating adhesive sheet with copper foil in which the holes for interlayer connection and the holes for cavities have been processed in advance, a press,
A vacuum press, a hot roll laminator, a vacuum laminator, etc. can be used. In this case, it is possible to optimize the circuit filling property, surface smoothness, and the flow rate of the insulating adhesive material from the interlayer connection hole by appropriately selecting the cushioning material and the lamination pressure during lamination. Can be experimentally determined depending on the type of device, the fluidity of the insulating adhesive material, and the type of circuit board to be laminated.

The composition of the insulating material of the insulating adhesive sheet or the insulating adhesive sheet with copper foil used in the present invention may be an epoxy resin type, a polyimide resin type, a phenol resin type or the like. It is preferable to add a flexibility-imparting component to this insulating material, which includes a polymer substance having good electrical insulation properties, such as a high molecular weight epoxy resin, an ultra high molecular weight epoxy resin, an acrylic rubber, NBR,
One or more kinds of epoxy-modified acrylic rubber, epoxidized polybutadiene, phenoxy resin and the like can be used. Moreover, in order to improve the adhesiveness between the copper foil and the insulating adhesive material, a silane coupling agent, which is a commercially available product, is NUC-A.
It is preferable to use 187, A189, A1160 (manufactured by Nippon Unicar Co., Ltd., trade name) in combination.

When an epoxy resin is used, it is desirable that the curing agent has a long varnish life and a high potential. For example, one or more of a tertiary amine, an acid anhydride, an imidazole compound, a polyphenol resin, a masked isocyanate and the like can be used. Can be used.

Further, this insulating adhesive sheet can be made to have a function shared by each layer by having a layer structure of two or more layers. For example, for the outermost layer, a low molecular weight epoxy resin can be used as a main component in order to improve the circuit filling property, and the layers other than the outermost layer are selected according to the characteristics required depending on the application of the multilayer wiring board. can do.
As an example, when heat resistance is required, a polyimide resin having good heat resistance of copper foil is used as the first layer, and an epoxy resin system having good circuit filling property is used as at least the outermost layer to improve heat resistance. And the circuit filling property can both be achieved. Further, by using a phenolic insulating adhesive material having good anti-tracking properties as the first layer and using an epoxy resin system having good circuit-filling properties as at least the outermost layer, it is possible to improve anti-tracking properties and circuit-filling properties. You can Incidentally, as a method of applying an insulating material to a copper foil or a supporting film, there are a bar coater, a lip coater, a roll coater and the like, but there are few defects such as craters and voids, and if the coating film thickness can be made substantially uniform, Any method will do.

For the interlayer connection, a method using conductive paste, plating, wire bonding, etc. can be used.

[0015]

【Example】

Example 1 (1) Varnish A (composition is shown in Table 1) on a copper foil having a thickness of 35 μm so that the thickness of the dried first layer would be 35 μm.
After coating, it is dried at 150 ° C. for 10 minutes, and a second layer having a thickness of 70 μm is formed on the first layer and the second layer after drying.
The varnish A was applied so that the thickness became m, and then dried at 110 ° C. for 10 minutes to produce an insulating adhesive material sheet with a copper foil. (2) The insulating adhesive sheet with a copper foil was punched at a portion for interlayer connection and a portion for forming a cavity. (3) A plating resist is formed on the shape of the circuit of the copper-clad laminate so as to expose the copper foil, electrolytic nickel plating is performed, the plating resist is peeled off, and then nickel plating is used as an etching resist. The glass-epoxy circuit board created by etching away unnecessary copper foil with an alkaline etchant and the copper foil-attached insulating adhesive sheet created in step (2) are laminated and integrated under heat and pressure. (4) An unnecessary portion of the copper foil is removed by etching to form a circuit. (5) A silver paste is used for interlayer connection. A multilayer board having interstitial via holes and cavities could be manufactured by the above method.

[0016]

According to the present invention, the formation of interstitial via holes and cavities can be efficiently manufactured. Moreover, since an insulating adhesive sheet or an insulating adhesive sheet with a copper foil is used, it is possible to reduce the thickness even when the number of layers to be laminated is large. Furthermore, since punching can be performed in advance on the insulating adhesive sheet or the insulating adhesive sheet with copper foil by a punch, a drill, etc., it is possible to obtain a multilayer wiring board with low cost and high reliability of the interlayer connection portion. .

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

Claims (6)

[Claims] 1. A pattern of a circuit shape is formed on a copper foil surface of a copper-clad laminate with a metal having an etching condition different from that of copper, the exposed copper foil is removed by etching, and an insulating adhesive is applied on the circuit. A sheet or an insulating adhesive sheet with a copper foil, which has been punched at a predetermined position, is laminated and integrated so that the insulating adhesive sheet contacts the circuit to form a circuit including interlayer connection. Method for manufacturing multilayer wiring board. 2. A circuit pattern is formed on a copper foil surface of a copper-clad laminate with a metal having an etching condition different from that of copper, the exposed copper foil is removed by etching, and an insulating adhesive is applied onto the circuit. A series of steps in which a sheet or an insulating adhesive sheet with copper foil, which has been punched at a predetermined position, is laminated and integrated so that the insulating adhesive sheet contacts the circuit to form a circuit including interlayer connection. A method for manufacturing a multilayer wiring board, characterized in that the above steps are repeated an arbitrary number of times. 3. As a method of forming a pattern in a circuit shape on a copper foil surface of a copper-clad laminate by using a metal having an etching condition different from that of copper, a plating resist is formed at a portion which does not become a circuit, and copper is formed. 3. The method for manufacturing a multilayer wiring board according to claim 1, wherein the metal is plated with different etching conditions. 4. A method for forming a pattern in a circuit shape on a surface of a copper foil of a copper-clad laminate by using a metal having an etching condition different from that of copper. The method for producing a multilayer wiring board according to claim 1 or 2, wherein different metals are plated on the entire surface, an etching resist is formed in a circuit shape, and only the metal is removed by etching. 5. The method for manufacturing a multilayer wiring board according to claim 3, wherein the plating is electrolytic plating. 6. A metal resist for forming a pattern in a circuit shape with a metal having a different etching condition from copper is used, and at least one member selected from the group consisting of nickel, gold, solder, tin and alloys thereof is used. The method for manufacturing a multilayer wiring board according to any one of claims 1 to 5, wherein: