JP2003168868A - Method for manufacturing printed circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a printed circuit board capable of obtaining a minute pattern in a high density by reducing a thickness of a surface conductor layer. <P>SOLUTION: The method for manufacturing the printed circuit board comprises the step of laminating the sides of copper foils 22 of a copper foil 24 with a carrier on both surfaces of an inner layer circuit board 20, thereby obtaining a laminate 25. The method further comprises the steps of perforating a hole 26 for an IVH at a predetermined position of the laminate 25, and forming a copper plating layer 27 on the entire surface of the laminate 25 including the hole 26. The method also comprises the steps of filling a conductive paste 29 in the IVH 28, removing the carriers 23 on the front and rear of the laminate 25, and polishing the surfaces of the foils 22, thereby obtaining the smooth surfaces. The method also comprises the steps of thereafter electrolytic copper plating the entire surface of the laminate 25 thinner than the plating layer 27 to form a copper plating layer 41, forming a required conductor pattern 42, thereby obtaining the printed circuit board 40. <P>COPYRIGHT: (C)2003,JPO

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 wiring board, and more particularly to a method for manufacturing a printed wiring board that requires a high-definition pattern.

[0002]

2. Description of the Related Art In general, the densification of a multilayer printed wiring board is performed by increasing the number of wiring layers.
If the number of wiring layers is simply increased, the number of through holes (through holes) for connecting the wirings of the respective layers increases, the area occupied by the through holes increases, and the amount of wiring accommodated decreases. Therefore, a method is used in which a connection hole is provided only in a portion where connection is required and a non-through hole IVH (interstitial via hole) is formed.

FIG. 3 shows a conventional method for providing a via hole SVH on the surface layer of a multilayer printed wiring board. Figure 3
As shown in (a), prepregs 2 are provided on both sides of the inner circuit board 1.
The copper foil 3 is laminated via the above to obtain a primary laminate 4. Next, as shown in FIG. 3B, a hole 5 penetrating the primary laminate 4 is formed at a predetermined position of the primary laminate 4, and the through hole 5 is formed.
By plating the entire surface of the primary laminate 4 including the inner surface thereof to form the plating layer 6, the front and back of the primary laminate 4 are electrically connected (FIG. 3C). Further, a circuit 7 is formed on the surface to be laminated of the primary laminate 4 to obtain an SVH layer 8 (FIG. 3).
(D)).

The SVH layer 8 thus formed has the circuit 7 forming surface and the other circuit 11 forming surface of the circuit board 10 having the copper foil 9 laminated on one surface thereof, with the prepreg 12 interposed therebetween. Then, the secondary laminated body 13 is obtained (FIG. 3E). Then, a hole 14 penetrating the secondary laminate 13 is formed at a predetermined position (FIG. 3 (f)), and the entire surface of the secondary laminate 13 including the inner surface of the through hole 14 is plated to form a plating layer 15. By forming it, the front and back of the secondary laminate 13 are electrically connected (FIG. 3 (g)). After that, the circuit 1 is formed on both surfaces of the secondary laminated body 13.
6 and 17 are formed to obtain a multilayer printed wiring board having SHV.

[0005]

In the multilayer printed wiring board having SVH thus formed, the SVH plating layer 6 and the through-hole plating layer 15 are formed on the copper foil 3.
However, the conductor thickness is increased in forming the circuits 16 and 17, and it is difficult to form a high-definition pattern with a narrow pitch. The half-etching technique is generally used as a method for reducing the thickness of the surface conductor to facilitate circuit formation, but there is a problem that it is difficult to control the etching amount due to variations in the plating thickness of the surface conductor. there were.

The present invention has been made to solve the above problems, and in a multilayer printed wiring board having IVH including SVH, the surface conductor layer is thinned to obtain a high density and fine pattern. It is an object to provide a method for manufacturing a plate.

[0007]

A method for manufacturing a printed wiring board according to the first invention comprises a. A step of stacking the copper foil surfaces of the carrier-attached copper foil on both surfaces of the inner layer circuit board via a prepreg to obtain a laminate, b. IVH penetrating the laminate
A step of forming a working hole at a predetermined position, plating the entire surface of the laminated body including the inside of the through hole, and electrically connecting the front and back of the laminated body by IVH; c. Removing the carriers on both sides of the laminate together with the plating layers on the carrier, d. Plating the entire surface of the laminate from which the carrier has been removed, e. And a step of forming circuits on both surfaces of the laminate. In this case, the IVH can be filled with a conductive paste to secure the connection reliability of the IVH, and a circuit can be formed on the IVH.

A method of manufacturing a printed wiring board according to the second invention is a method for manufacturing a printed wiring board comprising: a. A step of stacking the copper foil surfaces of the carrier-added copper foil on both surfaces of the inner layer circuit board via prepregs to obtain a primary laminate, b. A step of forming an IVH hole penetrating the primary laminate at a predetermined position, plating the entire surface of the primary laminate including the inside of the through hole, and electrically connecting the front and back of the primary laminate with IVH; c. Forming a circuit on the carrier removal surface side of the primary laminate to obtain an IVH layer, d. A step of laminating a circuit forming surface of the iVH layer and the other surface of a circuit board having a copper foil with a carrier laminated on one surface via a prepreg to obtain a secondary laminate, e. Forming a hole penetrating the secondary laminate at a predetermined position, f. Removing the carrier on both sides of the secondary laminate together with the plating layer on the carrier,
g. Plating the entire surface of the secondary laminate to electrically connect the front and back of the secondary laminate, h. And a step of forming circuits on both surfaces of the secondary laminated body.
In this case, the IVH can be filled with a conductive paste to secure the connection reliability of the IVH, and a circuit can be formed on the IVH.

According to the method for producing a printed wiring board according to the present invention, a plating for electrically connecting the front and back of the laminate is applied on the copper foil with a carrier, and then the carrier is removed together with the plating on the carrier. Since the circuit is formed by plating on the remaining copper foil, the thickness of the surface conductor (circuit) of the printed wiring board can be reduced, and a high-density and fine pattern can be obtained.

[0010]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an embodiment of a process for manufacturing a printed wiring board according to the first invention.

First, as shown in FIG. 1 (a), an inner layer circuit board formed by forming a conductor pattern at a required position on a glass cloth base material epoxy resin copper clad laminate such as FR-4 by a known subtractive method or the like. A copper foil 22 is attached to a carrier 23 via a prepreg 21 on both sides of the carrier 20 and the copper foil 22 side surface of a copper foil with a carrier 24 is laminated and laminated.
Get 5. Various types of the copper foil with carrier 24 are commercially available, but in the present embodiment, a carrier (carrier) 23 made of copper foil with a thickness of 70 μm is coated with electrolytic copper foil with a thickness of 9 μm, and manufactured by Furukawa Circuit Foil Co. A peelable electrolytic copper foil (trade name) was used. As the prepreg 21, it is possible to use one having an appropriate thickness in a B stage state in which a glass cloth base material epoxy resin is semi-cured.

Next, as shown in FIG. 1B, an IVH hole 26 penetrating the laminated body 25 is drilled at a predetermined position of the laminated body 25, and the laminated body including the inner surface of the through hole 26 is drilled. 25 is formed by electroless copper plating and electrolytic copper plating on the entire surface of 25 to form a copper plating layer 27.
An IVH 28 that electrically connects the front and back of No. 5 is obtained (Fig. 1
(C)).

These IVHs 28 are filled with a conductive paste 29 such as a silver paste by a squeegee method or the like (see FIG. 1).
(D)). Next, the carrier 23 including the copper plating layers 27 on the front and back sides of the laminated body 25 is mechanically peeled off and removed, and the conductive paste 29 that rises from the surface of the copper foil 22 and remains.
Is polished by buffing or the like to obtain a smooth surface (FIG. 1 (e)). In this case, when the carrier 23 is peeled off, I
Since the plating of the VH28 portion is also cut off, the connection reliability of the IVH28 may be impaired. Therefore, in this embodiment,
After the plating, the conductive paste 29 is filled in to ensure the connection reliability. However, if the carrier 23 can be peeled off without impairing the reliability, this filling may be omitted.

Thereafter, the laminated body 2 from which the carrier 23 has been removed
The entire surface of 5 is electrolytically copper-plated thinner than the copper-plated layer 27 to form a copper-plated layer 41 (FIG. 1 (f)), and a circuit (conductor pattern) 42 is formed on a required portion including the IVH 29 by a subtractive method or the like. Forming a printed wiring board 40
(FIG. 1 (g)). Although the circuit 42 is formed by performing panel plating on the copper foil 22 in FIG. 1, the circuit 42 may be formed by pattern plating.

According to this embodiment, after the plating for electrically connecting the front and back of the laminated body is applied on the copper foil with the carrier, the carrier is removed together with the plating on the carrier,
Since the circuit is formed by plating on the remaining copper foil, the thickness of the surface conductor (circuit) of the printed wiring board can be reduced, and a high-density and fine pattern can be obtained.

FIG. 2 shows the IVH (SVH) according to the second invention.
FIG. 7 is a schematic cross-sectional view showing one embodiment of a manufacturing process of a multilayer printed wiring board having a structure. 2, parts that are the same as or equivalent to those in FIG. 1 are assigned the same reference numerals and detailed explanations thereof are omitted.

First, as shown in FIG. 2A, the copper foil 22 side surface of the copper foil with carrier 24 is placed on both sides of the inner layer circuit board 20 having conductor patterns formed at required positions via the prepreg 21. The first laminate 25 is obtained by stacking and stacking. Then, as shown in FIG. 1B, a hole 26 penetrating the primary laminated body 25 is drilled at a predetermined position of the primary laminated body 25, and then the carrier 23 on one surface (the lower surface side in the drawing) is attached. It is removed by mechanical peeling, and the entire surface of the primary laminated body 25 including the inner surface of the through hole 26 is electrolessly copper-plated and electrolytic copper-plated to form a copper-plated layer 27. An IVH 28 that electrically connects the front and back is obtained (FIG. 1 (c)).

These IVHs 28 are filled with a conductive paste 29 such as a silver paste (FIG. 1 (d)), a conductor pattern 30 is formed at a required portion on the carrier removal surface side of the primary laminate 25, and an IVH layer 31 is formed. Is obtained (FIG. 1 (e)). The IVH layer 31 thus formed has the circuit 30 forming surface and the circuit 33 forming surface of the other surface of the circuit board 32 having the carrier-attached copper foil 24 laminated on one surface thereof via the prepreg 21. A secondary laminated body 34 is obtained by laminating (see FIG. 1).
(F)).

After forming a hole (through hole) 35 penetrating the secondary laminated body 34 at a predetermined position (see FIG. 1).
(G)), the carrier 23 on the circuit board 32 side of the secondary laminate 34 and the carrier 23 including the copper plating layer 27 on the IVH layer 31 side are mechanically peeled and removed (FIG. 1 (h)), Conductive paste 29 rising from the surface of the foil 22 and remaining
Is polished by buffing or the like to obtain a smooth surface. Also in this embodiment, if the connection reliability of the IVH 28 can be secured, the filling of the IVH 28 can be omitted.

Thereafter, the entire surface of the secondary laminated body 34 including the inner surface of the through hole 35 is electrolessly copper-plated and electrolytic copper-plated to form a copper plating layer 36, whereby the secondary laminated body 34 is formed.
A through hole 37 for electrically connecting the front and back sides of is obtained (FIG. 1 (i)). Next, the circuits 38 and 39 are formed on both surfaces of the secondary laminate 34 by a subtractive method or the like at required locations including on the IVH 28 to obtain a printed wiring board 50 having IHV (FIG. 1 (j)).

According to this embodiment, since the carrier on the surface of the IVH layer is plated with the through-hole, the carrier is removed together with the plating on the carrier, and the remaining copper foil is plated to form a circuit. The thickness of the surface conductor (circuit) of the board can be reduced, and a printed wiring board having an IVH structure having a high-density and fine pattern can be obtained.

[0022]

EFFECTS OF THE INVENTION According to the present invention, after the plating for electrically connecting the front and back of the laminate such as IVH and through holes is applied to the carrier, the carrier is removed together with this plating, and the remaining copper foil is removed. Since the circuit is formed by plating on the copper foil, the plating layer at the time of forming the IVH or the through hole is not accumulated and deposited on the copper foil, and the conductor thickness does not become thick in forming the circuit. The thickness of the surface conductor (circuit) of the printed wiring board can be reduced, and a printed wiring board having a high density and fine pattern can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a manufacturing process of a printed wiring board which is an embodiment of the present invention.

FIG. 2 is a schematic view showing a manufacturing process of a printed wiring board which is another embodiment of the present invention.

FIG. 3 is a schematic view showing a manufacturing process of a conventional multilayer printed wiring board.

[Explanation of symbols]

20 inner layer circuit board 22 Copper foil 23 career 24 Carrier with copper foil 25 (Primary) laminate 26, 35 holes 27, 36 Plating layer 28 IVH 29 Conductive paste 30, 38, 39, 42 circuits 31 IVH layer 34 Secondary stack 37 Through hole

Claims (3)

[Claims] 1. A. Step of obtaining a laminate by stacking and laminating the copper foil surfaces of the carrier-added copper foil on both surfaces of the inner layer circuit board via prepregs b. IVH hole penetrating the laminate is formed at a predetermined position, the entire surface of the laminate including the inside of the through hole is plated, and the front and back of the laminate are electrically connected by IVH. C. Removing the carriers on both sides of the laminate together with the plating layers on the carrier d. A step of plating the entire surface of the laminate from which the carrier has been removed e. A method of manufacturing a printed wiring board, comprising a step of forming circuits on both surfaces of the laminate. 2. A. A step of stacking the copper foil surfaces of the carrier-added copper foil on both surfaces of the inner layer circuit board via prepregs to obtain a primary laminate b. Step of forming an IVH hole penetrating the primary laminate at a predetermined position, plating the entire surface of the primary laminate including the inside of the through hole, and electrically connecting the front and back sides by IVH. C. Step of forming a circuit on the carrier removal surface side of the primary laminate to obtain an IVH layer d. A step of laminating a circuit forming surface of the IVH layer and the other surface of a circuit board having a copper foil with a carrier laminated on one surface via a prepreg to obtain a secondary laminate e. Step of forming a hole penetrating the secondary laminated body at a predetermined position f. Removing the carriers on both sides of the secondary laminate together with the plating layers on the carrier g. Step of plating the entire surface of the secondary laminate to electrically connect the front and back sides h. A method of manufacturing a printed wiring board, comprising a step of forming a circuit on both surfaces of the secondary laminate. 3. The method for manufacturing a printed wiring board according to claim 1, wherein the IVH is filled with a conductive paste.