JPH05251867A - Manufacture of multi-layered circuit board - Google Patents

Abstract

PURPOSE:To shorten the manufacturing time as a whole, improve productivity, and lower the manufacturing cost by laminating a insulated resin sheet to which the metal foil is fixed with a hole provided in advance in order to reduce the time for boring process. CONSTITUTION:On the surface of an inner layer circuit board 3, there is laminated an insulated resin sheet 6 to which a metal foil is fixed with a hole 9 provided in advance. Then, a plating layer 13 is formed in the hole 9 by a plating process. Further, an outer layer circuit 15 is formed to manufacture a multi- layered circuit board.

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 A multilayer wiring board is manufactured, for example, as follows. That is, a double-sided copper-clad laminate having an inner layer circuit formed on the central substrate is used. Then, a prepreg made of a glass cloth resin-impregnated cloth is laminated on both sides of this laminated plate. Next, a circuit-formed copper-clad laminate, a prepreg, and a copper foil are sequentially laminated on the surface of the prepreg. After the lamination, pins are set up in the reference holes provided on the left and right of the laminated plate, prepreg, etc., and aligned, pressed, and heated and pressed. After pressing, the board is applied to the multilayer board. Then, fix the end with tape or the like so that this plate does not move. In this state, a non-through hole is formed from the copper foil on the surface to the circuit one layer below using a drill or a laser. Then, a through hole is formed using a drill or the like. After forming the through holes, the contact plate is removed, and electroless copper plating treatment and electrolytic copper plating treatment are performed to form a plating layer in each hole. Next, the copper foil on the surface is etched by tenting to form a circuit.

[0003]

In order to reduce the manufacturing time, it is sufficient to stack a plurality of multi-layer boards in the punching step. However, in this state, although the through hole can be formed, the non-through hole cannot be formed. Therefore, there is a drawback that the holes have to be formed one by one, the work takes time, the productivity is low, and the manufacturing cost is hindered.

An object of the present invention is to provide a method for manufacturing a multilayer wiring board, which is capable of improving the above drawbacks, shortening the manufacturing time and improving the productivity, and reducing the manufacturing cost.

[0005]

In order to achieve the above object, the present invention provides a step of laminating an insulating resin sheet with a metal foil provided with holes on the surface of an inner layer circuit board, and plating after this step. It is intended to provide a method for manufacturing a multilayer wiring board, which comprises a step of performing a treatment to form a plating layer in the hole and a step of forming an outer layer circuit after this step.

The insulating resin sheet is mainly composed of a thermosetting resin such as an epoxy resin, an epoxidized polybutadiene resin, a phenol resin, a modified polyamideimide resin or a modified polyimide resin, and is made of polybutadiene, styrene butadiene rubber, acrylonitrile rubber or phenoxy resin. For example, a compound containing a flexible polymer compound and an inorganic filler is used. Then, after laminating a copper foil on this insulating resin sheet, holes are made in advance using a hole making machine.

The plating layer in the hole is formed by sequentially performing electroless plating treatment and electrolytic plating treatment.

[0008]

Since the insulating sheet with the one-sided metal foil in which the holes are provided in advance is laminated on the surface of the inner layer circuit board, the step of forming the non-through holes can be omitted. Therefore, in the punching step, only the through holes need to be formed, a plurality of sheets can be processed at one time, and the productivity is increased.

[0009]

EXAMPLES The present invention will be described below based on examples. Example 1: As shown in FIG. 1 (a), a central substrate is provided with a two-layer circuit 1 on an inner layer, and copper foils 2 are attached to both outer surfaces of the inner layer. To use. This laminated plate 3 is provided with a reference hole 4 at its end in advance.
Then, the surface of the copper foil 2 is etched to form a circuit 5 as shown in FIG. After forming the circuit 5, this circuit 5
The surface is subjected to redox treatment.

An insulating resin sheet 6 with a metal foil on one side is also provided.
As shown in FIG. 1C, a copper foil 8 having a surface in contact with the sheet 7 is laminated on one surface of an insulating resin sheet 7 having a thickness of 200 μm, and the temperature is 160 ° C. and the pressure is 2 to 5 kg / cm. Press for ² minutes for 60 minutes, heat and pressurize, 500mm × 1000mm
It shall be formed in the corner. Then, a hole 9 of 0.2φ is made in this sheet 6 by a horizontal small-diameter punching machine. After the hole 9 is formed, it is cut into a 200 mm × 500 mm square, and the reference holes 10 are formed at both ends.

Next, as shown in FIG. 1D, the sheet 6 is laminated on the double-sided copper-clad laminate 3. At this time, sheet 6
The hole 9 provided in the circuit board 5 is arranged on the circuit 5 provided in the laminated plate 3. Since the surface of the circuit 5 is subjected to the redox treatment, the adhesion is good. After stacking, the pins 11 are set up in the reference holes 4 and 10 provided in the laminate 3 and the sheet 6 and positioned. Then, the sheet 6 is pressed and heated and pressed to bring the sheet 6 into close contact with the laminated plate 3.

After the pressing, as shown in FIG. 1 (e), holes 12 penetrating the sheet 6 and the laminated plate 3 are formed by a drill or the like. After the through hole 12 is formed, smearing is performed to remove the smear.

After smearing, electroless copper plating and electrolytic copper plating are performed to form copper plating layers 13 and 14 in the non-through holes 9 and the through holes 12, respectively, as shown in FIG. ..

After forming the copper plating layers 13 and 14, FIG.
As shown in (g), the outer layer circuit 15 is formed by treating the copper foil 8 on the surface of the sheet 7 by the tenting method.

After the outer layer circuit 15 is formed, solder resist printing is performed to form the solder resist layer 1 as shown in FIG.
6 is formed.

Next, for the above-mentioned Example 1 and the conventional example, the interlayer adhesion and the peel strength of the copper foil were determined and a thermal shock test was conducted.

The manufacturing method of the conventional example is as follows. Conventional Example 1: As shown in FIG. 2 (a), two double-sided copper-clad laminates 22 each having a circuit 21 formed on both sides thereof are laminated via a prepreg 23 of a glass cloth resin impregnated cloth, and the opposite sides are also laminated with each other. The prepregs 24 and 25 of the same material are piled up. Further, copper foils 26 and 27 are overlaid on the prepregs 24 and 25, respectively. Then, the reference holes 2 provided in the laminated plate 22, the prepregs 23 to 25, and the copper foils 26 and 27, respectively.
Align pins 8 to 33 with each other through pins 34. After alignment, press and heat and press to bring them into close contact with each other. After pressing, as shown in Fig. 2 (b), with a drill, from the circuit of the outermost layer to the layer one layer below, a hole 3 of 0.2φ is formed.
Open 5 Also, a hole 3 that penetrates each layer with a drill
Open 6 After forming the holes 35 and 36, electroless copper plating and electrolytic copper plating are performed in the same manner as in Example 1 to form a plating layer in the holes. Further, the outermost circuit and the solder resist layer are formed by the same method as in the first embodiment.

The interlayer adhesion, copper foil peeling strength, and thermal shock test evaluations and circuit patterns are as follows.

I) Interlayer adhesion The sample is dipped in a solder bath at a temperature of 260 ° C., and the time at which swelling occurs in the poor adhesion area is measured. As the circuit pattern, the JIS-C5012 multilayer printed board composite test pattern 9 is used.

Ii) Copper foil peeling strength A portion of the surface copper foil is peeled off in advance, the peeled portion is fixed with a pin, and peeled off at a speed of 5 mm / min using an autograph. The load was calculated. The circuit pattern is the same as that used for interlayer adhesion.

Iii) Thermal shock test JIS-C5012 temperature and humidity cycle 65 ° C., 93%,
By repeating 4 Hr, 25 ° C., 80%, and 1 Hr, the number of cycles at which the resistance of the plated layer of the through hole increased to 10% of the initial value was determined. The circuit pattern is JIS-
A composite test pattern L for C5012 multilayer printed board is used.

The measurement results are shown in Table 1.

[Table 1]

As is clear from Table 1, according to Example 1, the same result as that of Conventional Example 1 can be obtained. Further, the interlayer adhesion and the peel strength of the copper foil sufficiently satisfy the JIS standard values.

The change in insulation resistance between layers was measured for the present invention and the conventional example. The manufacturing conditions of the example of the present invention and the conventional example are as follows.

Example 2 In Example 1, the composite test pattern M for JIS-C5012 multilayer printed board was used as the circuit pattern, and the thickness of the insulating resin sheet was set to 1
It is manufactured under the same conditions except that the thickness is set to 00 μm.

Example 3: The procedure of Example 2 was repeated except that the insulating resin sheet had a thickness of 200 μm.

Conventional Example 2: In Conventional Example 1, the glass cloth resin-impregnated cloth is manufactured under the same conditions except that the thickness of the prepreg is 100 μm.

Conventional Example 3: Manufactured under the same conditions as in Conventional Example 1, except that the thickness of the prepreg of the glass cloth resin-impregnated cloth is 200 μm.

Then, the test was conducted with the sample at a temperature of 85 ° C. and a humidity of 8
DC100V is applied to the circuit in an atmosphere of 5% RH and left for 1000 hours. Insulation resistance is DC25
0 V was applied and the value was measured for 1 minute.

The measurement results are shown in Table 2.

[Table 2]

As is apparent from Table 2, according to the second and third embodiments, the same insulation resistance as that of the second and third conventional examples can be obtained. In particular, the thinner example 2 obtained better results than the conventional example 2.

[0032]

As described above, according to the manufacturing method of the present invention, since the insulating resin sheet with the metal foil in which the holes are provided in advance is laminated, the processing time in the perforating step can be shortened, and as a whole. Manufacturing time can be shortened, productivity is improved,
A multilayer wiring board that can reduce the manufacturing cost can be obtained. Also,
According to the manufacturing method of the present invention, it is not always necessary to use the glass cloth resin-impregnated cloth. Therefore, when holes are drilled by a laser, the glass thread remains and the shape of the holes does not deteriorate after the plating treatment, or the plating does not adhere, and it is possible to reduce defects and obtain a highly reliable multilayer wiring board. Furthermore, when drilling with a drill, if it is necessary to use a glass cloth resin impregnated cloth that has relatively high cutting resistance, the life of the drill can be extended and less drill replacement work is required. A multilayer wiring board with improved productivity and reduced cost can be obtained.

[Brief description of drawings]

FIG. 1 shows a drawing of a manufacturing process according to an embodiment of the present invention.

FIG. 2 shows a drawing of a manufacturing process of a conventional example.

[Explanation of symbols]

3 ... Inner layer, double-sided copper clad laminate with circuit, 6 ... Insulating resin sheet with one side metal foil, 9 ... Hole, 13 ... Copper plating layer, 15 ... Outer layer circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyoshi Yokoyama 413 Kushimoda, Ninomiya-cho, Haga-gun, Tochigi Prefecture Hitachi AIC Co., Ltd.

Claims (1)

[Claims] 1. A step of laminating an insulating resin sheet with a metal foil provided with holes on the surface of an inner layer circuit board, a step of plating after this step to form a plating layer in the holes, and this step A method of manufacturing a multilayer wiring board, the method further comprising the step of forming an outer layer circuit later.